1
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Kettel P, Marosits L, Spinetti E, Rechberger M, Giannini C, Radler P, Niedermoser I, Fischer I, Versteeg GA, Loose M, Covino R, Karagöz GE. Disordered regions in the IRE1α ER lumenal domain mediate its stress-induced clustering. EMBO J 2024:10.1038/s44318-024-00207-0. [PMID: 39232130 DOI: 10.1038/s44318-024-00207-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/02/2024] [Accepted: 07/23/2024] [Indexed: 09/06/2024] Open
Abstract
Conserved signaling cascades monitor protein-folding homeostasis to ensure proper cellular function. One of the evolutionary conserved key players is IRE1, which maintains endoplasmic reticulum (ER) homeostasis through the unfolded protein response (UPR). Upon accumulation of misfolded proteins in the ER, IRE1 forms clusters on the ER membrane to initiate UPR signaling. What regulates IRE1 cluster formation is not fully understood. Here, we show that the ER lumenal domain (LD) of human IRE1α forms biomolecular condensates in vitro. IRE1α LD condensates were stabilized both by binding to unfolded polypeptides as well as by tethering to model membranes, suggesting their role in assembling IRE1α into signaling-competent stable clusters. Molecular dynamics simulations indicated that weak multivalent interactions drive IRE1α LD clustering. Mutagenesis experiments identified disordered regions in IRE1α LD to control its clustering in vitro and in cells. Importantly, dysregulated clustering of IRE1α mutants led to defects in IRE1α signaling. Our results revealed that disordered regions in IRE1α LD control its clustering and suggest their role as a common strategy in regulating protein assembly on membranes.
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Affiliation(s)
- Paulina Kettel
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Laura Marosits
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
| | - Elena Spinetti
- Frankfurt Institute for Advanced Studies, Frankfurt, Germany
- Institute of Biophysics, Goethe University, Frankfurt, Germany
| | | | - Caterina Giannini
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Philipp Radler
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Isabell Niedermoser
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
| | - Irmgard Fischer
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
| | - Gijs A Versteeg
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria
- Department of Microbiology, Immunobiology and Genetics, University of Vienna, Vienna, Austria
| | - Martin Loose
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Roberto Covino
- Frankfurt Institute for Advanced Studies, Frankfurt, Germany
- IMPRS on Cellular Biophysics, Frankfurt, Germany
| | - G Elif Karagöz
- Max Perutz Laboratories Vienna, Vienna BioCenter, Vienna, Austria.
- Medical University of Vienna, Vienna, Austria.
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2
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Moghadam RK, Daraei A, Haddadi M, Mardi A, Karamali N, Rezaiemanesh A. Casting Light on the Janus-Faced HMG-CoA Reductase Degradation Protein 1: A Comprehensive Review of Its Dualistic Impact on Apoptosis in Various Diseases. Mol Neurobiol 2024; 61:6842-6863. [PMID: 38356096 DOI: 10.1007/s12035-024-03994-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024]
Abstract
Nowadays, it is well recognized that apoptosis, as a highly regulated cellular process, plays a crucial role in various biological processes, such as cell differentiation. Dysregulation of apoptosis is strongly implicated in the pathophysiology of numerous disorders, making it essential to comprehend its underlying mechanisms. One key factor that has garnered significant attention in the regulation of apoptotic pathways is HMG-CoA reductase degradation protein 1, also known as HRD1. HRD1 is an E3 ubiquitin ligase located in the endoplasmic reticulum (ER) membrane. Its primary role involves maintaining the quality control of ER proteins by facilitating the ER-associated degradation (ERAD) pathway. During ER stress, HRD1 aids in the elimination of misfolded proteins that accumulate within the ER. Therefore, HRD1 plays a pivotal role in the regulation of apoptotic pathways and maintenance of ER protein quality control. By targeting specific protein substrates and affecting apoptosis-related pathways, HRD1 could be an exclusive therapeutic target in different disorders. Dysregulation of HRD1-mediated processes contributes significantly to the pathophysiology of various diseases. The purpose of this review is to assess the effect of HRD1 on the pathways related to apoptosis in various diseases from a therapeutic perspective.
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Affiliation(s)
- Reihaneh Khaleghi Moghadam
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran
| | - Arshia Daraei
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran
| | - Maryam Haddadi
- Student Research Committee, School of Medicine, Kermanshah University of Medical Sciences, Kermanshah, Iran
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran
| | - Amirhossein Mardi
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Negin Karamali
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
- Department of Immunology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Alireza Rezaiemanesh
- Department of Immunology, School of Medicine, Kermanshah University of Medical Sciences, Daneshgah Street, Shahid Shiroudi Boulevard, PO-Box: 6714869914, Kermanshah, Iran.
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3
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Rohli KE, Stubbe NJ, Walker EM, Pearson GL, Soleimanpour SA, Stephens SB. A metabolic redox relay supports ER proinsulin export in pancreatic islet β cells. JCI Insight 2024; 9:e178725. [PMID: 38935435 PMCID: PMC11383593 DOI: 10.1172/jci.insight.178725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 06/18/2024] [Indexed: 06/29/2024] Open
Abstract
ER stress and proinsulin misfolding are heralded as contributing factors to β cell dysfunction in type 2 diabetes, yet how ER function becomes compromised is not well understood. Recent data identify altered ER redox homeostasis as a critical mechanism that contributes to insulin granule loss in diabetes. Hyperoxidation of the ER delays proinsulin export and limits the proinsulin supply available for insulin granule formation. In this report, we identified glucose metabolism as a critical determinant in the redox homeostasis of the ER. Using multiple β cell models, we showed that loss of mitochondrial function or inhibition of cellular metabolism elicited ER hyperoxidation and delayed ER proinsulin export. Our data further demonstrated that β cell ER redox homeostasis was supported by the metabolic supply of reductive redox donors. We showed that limiting NADPH and thioredoxin flux delayed ER proinsulin export, whereas thioredoxin-interacting protein suppression restored ER redox and proinsulin trafficking. Taken together, we propose that β cell ER redox homeostasis is buffered by cellular redox donor cycles, which are maintained through active glucose metabolism.
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Affiliation(s)
- Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Emily M Walker
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Gemma L Pearson
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Scott A Soleimanpour
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- VA Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
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4
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Zhang Y, Sui L, Du Q, Haataja L, Yin Y, Viola R, Xu S, Nielsson CU, Leibel RL, Barbetti F, Arvan P, Egli D. Permanent neonatal diabetes-causing insulin mutations have dominant negative effects on beta cell identity. Mol Metab 2024; 80:101879. [PMID: 38237895 PMCID: PMC10839447 DOI: 10.1016/j.molmet.2024.101879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/08/2024] [Accepted: 01/09/2024] [Indexed: 01/25/2024] Open
Abstract
OBJECTIVE Heterozygous coding sequence mutations of the INS gene are a cause of permanent neonatal diabetes (PNDM), requiring insulin therapy similar to T1D. While the negative effects on insulin processing and secretion are known, how dominant insulin mutations result in a continued decline of beta cell function after birth is not well understood. METHODS We explored the causes of beta cell failure in two PNDM patients with two distinct INS mutations using patient-derived iPSCs and mutated hESCs. RESULTS we detected accumulation of misfolded proinsulin and impaired proinsulin processing in vitro, and a dominant-negative effect of these mutations on beta-cell mass and function after transplantation into mice. In addition to anticipated ER stress, we found evidence of beta-cell dedifferentiation, characterized by an increase of cells expressing both Nkx6.1 and ALDH1A3, but negative for insulin and glucagon. CONCLUSIONS These results highlight a novel mechanism, the loss of beta cell identity, contributing to the loss and functional failure of human beta cells with specific insulin gene mutations.
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Affiliation(s)
- Yuwei Zhang
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Lina Sui
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Qian Du
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Leena Haataja
- Metabolism Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI 48105, United States
| | - Yishu Yin
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Ryan Viola
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Shuangyi Xu
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Christian Ulrik Nielsson
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Rudolph L Leibel
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States
| | - Fabrizio Barbetti
- Department of Experimental Medicine, University of Rome Tor Vergata, Rome 00133, Italy; Monogenic Diabetes Clinic, Endocrinology and Diabetes Unit, Bambino Gesù Children's Hospital, Rome 00164, Italy
| | - Peter Arvan
- Metabolism Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI 48105, United States
| | - Dieter Egli
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, United States.
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5
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(Flintoaca) Alexandru PR, Chiritoiu GN, Lixandru D, Zurac S, Ionescu-Targoviste C, Petrescu SM. EDEM1 regulates the insulin mRNA level by inhibiting the endoplasmic reticulum stress-induced IRE1/JNK/c-Jun pathway. iScience 2023; 26:107956. [PMID: 37822496 PMCID: PMC10562789 DOI: 10.1016/j.isci.2023.107956] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 07/22/2023] [Accepted: 09/14/2023] [Indexed: 10/13/2023] Open
Abstract
Pancreatic beta cells produce and secrete insulin as a response to rises in blood glucose. Despite the advances in understanding glucose-regulated insulin transcription and translation the mechanisms triggering the synthesis of new insulin molecules are still incompletely described. In this report, we identify EDEM1 as a new modulator of insulin synthesis and secretion. In the presence of EDEM1, INS-1E cells secrete significantly more insulin upon glucose stimulation compared to control cells. We found that overexpression of EDEM1 inhibited the IRE1/JNK/c-Jun pathway, leading to an increase in the insulin mRNA level. Similarly, EDEM1 transduced human islets secreted significantly more insulin upon stimulation. Furthermore, EDEM1 improved insulin secretion restoring normoglycemia and glucose tolerance in diabetic rats. We propose EDEM1 as a regulator of the UPR via IRE1/XBP1s and IRE1/JNK/c-Jun signaling cascades and insulin transcription in pancreatic β-cells, supporting EDEM1 as a potential target for the treatment of diabetes.
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Affiliation(s)
| | - Gabriela N. Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry, Romanian Academy, 060031 Bucharest, Romania
| | - Daniela Lixandru
- Department of Biochemistry, “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Sabina Zurac
- Department of Physiology, “Carol Davila” University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | | | - Stefana M. Petrescu
- Department of Molecular Cell Biology, Institute of Biochemistry, Romanian Academy, 060031 Bucharest, Romania
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6
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Zhang Y, Sui L, Du Q, Haataja L, Yin Y, Viola R, Xu S, Nielsson CU, Leibel RL, Barbetti F, Arvan P, Egli D. Permanent Neonatal diabetes-causing Insulin mutations have dominant negative effects on beta cell identity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.01.555839. [PMID: 37745320 PMCID: PMC10515756 DOI: 10.1101/2023.09.01.555839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Heterozygous coding sequence mutations of the INS gene are a cause of permanent neonatal diabetes (PNDM) that results from beta cell failure. We explored the causes of beta cell failure in two PNDM patients with two distinct INS mutations. Using b and mutated hESCs, we detected accumulation of misfolded proinsulin and impaired proinsulin processing in vitro, and a dominant-negative effect of these mutations on the in vivo performance of patient-derived SC-beta cells after transplantation into NSG mice. These insulin mutations derange endoplasmic reticulum (ER) homeostasis, and result in the loss of beta-cell mass and function. In addition to anticipated apoptosis, we found evidence of beta-cell dedifferentiation, characterized by an increase of cells expressing both Nkx6.1 and ALDH1A3, but negative for insulin and glucagon. These results highlight both known and novel mechanisms contributing to the loss and functional failure of human beta cells with specific insulin gene mutations.
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Affiliation(s)
- Yuwei Zhang
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
- These authors contributed equally
| | - Lina Sui
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
- These authors contributed equally
| | - Qian Du
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
| | - Leena Haataja
- Metabolism Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI 48105, United States
| | - Yishu Yin
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
| | - Ryan Viola
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
| | - Shuangyi Xu
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
| | - Christian Ulrik Nielsson
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
| | - Rudolph L. Leibel
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
| | - Fabrizio Barbetti
- Department of Experimental Medicine, University of Rome Tor Vergata, Rome 00133, Italy
- Monogenic Diabetes Clinic, Endocrinology and Diabetes Unit, Bambino Gesù Children’s Hospital, Rome 00164, Italy
| | - Peter Arvan
- Metabolism Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI 48105, United States
| | - Dieter Egli
- Naomi Berrie Diabetes Center & Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York, 10032, United States
- Lead Contact
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7
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Mohammadi-Motlagh HR, Sadeghalvad M, Yavari N, Primavera R, Soltani S, Chetty S, Ganguly A, Regmi S, Fløyel T, Kaur S, Mirza AH, Thakor AS, Pociot F, Yarani R. β Cell and Autophagy: What Do We Know? Biomolecules 2023; 13:biom13040649. [PMID: 37189396 DOI: 10.3390/biom13040649] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 05/17/2023] Open
Abstract
Pancreatic β cells are central to glycemic regulation through insulin production. Studies show autophagy as an essential process in β cell function and fate. Autophagy is a catabolic cellular process that regulates cell homeostasis by recycling surplus or damaged cell components. Impaired autophagy results in β cell loss of function and apoptosis and, as a result, diabetes initiation and progress. It has been shown that in response to endoplasmic reticulum stress, inflammation, and high metabolic demands, autophagy affects β cell function, insulin synthesis, and secretion. This review highlights recent evidence regarding how autophagy can affect β cells' fate in the pathogenesis of diabetes. Furthermore, we discuss the role of important intrinsic and extrinsic autophagy modulators, which can lead to β cell failure.
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Affiliation(s)
- Hamid-Reza Mohammadi-Motlagh
- Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah 67155-1616, Iran
| | - Mona Sadeghalvad
- Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran 1416634793, Iran
| | - Niloofar Yavari
- Department of Cellular and Molecular Medicine, The Panum Institute, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Rosita Primavera
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Setareh Soltani
- Clinical Research Development Center, Taleghani and Imam Ali Hospital, Kermanshah University of Medical Sciences, Kermanshah 67145-1673, Iran
| | - Shashank Chetty
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Abantika Ganguly
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Shobha Regmi
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Tina Fløyel
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
| | - Simranjeet Kaur
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
| | - Aashiq H Mirza
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
- Department of Pharmacology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Avnesh S Thakor
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Flemming Pociot
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
- Institute for Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Reza Yarani
- Interventional Regenerative Innovation at Stanford (IRIS), Department of Radiology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
- Translational Type 1 Diabetes Research, Department of Clinical Research, Steno Diabetes Center Copenhagen, 2730 Herlev, Denmark
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8
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Maloshenok LG, Abushinova GA, Ryazanova AY, Bruskin SA, Zherdeva VV. Visualizing the Nucleome Using the CRISPR–Cas9 System: From in vitro to in vivo. BIOCHEMISTRY (MOSCOW) 2023; 88:S123-S149. [PMID: 37069118 PMCID: PMC9940691 DOI: 10.1134/s0006297923140080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
One of the latest methods in modern molecular biology is labeling genomic loci in living cells using fluorescently labeled Cas protein. The NIH Foundation has made the mapping of the 4D nucleome (the three-dimensional nucleome on a timescale) a priority in the studies aimed to improve our understanding of chromatin organization. Fluorescent methods based on CRISPR-Cas are a significant step forward in visualization of genomic loci in living cells. This approach can be used for studying epigenetics, cell cycle, cellular response to external stimuli, rearrangements during malignant cell transformation, such as chromosomal translocations or damage, as well as for genome editing. In this review, we focused on the application of CRISPR-Cas fluorescence technologies as components of multimodal imaging methods for in vivo mapping of chromosomal loci, in particular, attribution of fluorescence signal to morphological and anatomical structures in a living organism. The review discusses the approaches to the highly sensitive, high-precision labeling of CRISPR-Cas components, delivery of genetically engineered constructs into cells and tissues, and promising methods for molecular imaging.
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Affiliation(s)
- Liliya G Maloshenok
- Bach Institute of Biochemistry, Federal Research Center for Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Gerel A Abushinova
- Bach Institute of Biochemistry, Federal Research Center for Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Alexandra Yu Ryazanova
- Bach Institute of Biochemistry, Federal Research Center for Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia
| | - Sergey A Bruskin
- Bach Institute of Biochemistry, Federal Research Center for Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia
- Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Victoria V Zherdeva
- Bach Institute of Biochemistry, Federal Research Center for Biotechnology of the Russian Academy of Sciences, Moscow, 119071, Russia.
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9
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Ching C, Iich E, Teo AKK. Harnessing Human Pluripotent Stem Cell-Derived Pancreatic In Vitro Models for High-Throughput Toxicity Testing and Diabetes Drug Discovery. Handb Exp Pharmacol 2023; 281:301-332. [PMID: 37306817 DOI: 10.1007/164_2023_655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The long-standing goals in diabetes research are to improve β-cell survival, functionality and increase β-cell mass. Current strategies to manage diabetes progression are still not ideal for sustained maintenance of normoglycemia, thereby increasing demand for the development of novel drugs. Available pancreatic cell lines, cadaveric islets, and their culture methods and formats, either 2D or 3D, allow for multiple avenues of experimental design to address diverse aims in the research setting. More specifically, these pancreatic cells have been employed in toxicity testing, diabetes drug screens, and with careful curation, can be optimized for use in efficient high-throughput screenings (HTS). This has since spearheaded the understanding of disease progression and related mechanisms, as well as the discovery of potential drug candidates which could be the cornerstone for diabetes treatment. This book chapter will touch on the pros and cons of the most widely used pancreatic cells, including the more recent human pluripotent stem cell-derived pancreatic cells, and HTS strategies (cell models, design, readouts) that can be used for the purpose of toxicity testing and diabetes drug discovery.
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Affiliation(s)
- Carmen Ching
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Precision Medicine Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Elhadi Iich
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Adrian Kee Keong Teo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Precision Medicine Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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10
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Yang J, Zhen J, Feng W, Fan Z, Ding L, Yang X, Huang Y, Shu H, Xie J, Li X, Qiao J, Fan Y, Sun J, Li N, Liu T, Wang S, Zhang X, Arvan P, Liu M. IER3IP1 is critical for maintaining glucose homeostasis through regulating the endoplasmic reticulum function and survival of β cells. Proc Natl Acad Sci U S A 2022; 119:e2204443119. [PMID: 36322741 PMCID: PMC9659391 DOI: 10.1073/pnas.2204443119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Accepted: 10/06/2022] [Indexed: 05/04/2023] Open
Abstract
Recessive mutations in IER3IP1 (immediate early response 3 interacting protein 1) cause a syndrome of microcephaly, epilepsy, and permanent neonatal diabetes (MEDS). IER3IP1 encodes an endoplasmic reticulum (ER) membrane protein, which is crucial for brain development; however, the role of IER3IP1 in β cells remains unknown. We have generated two mouse models with either constitutive or inducible IER3IP1 deletion in β cells, named IER3IP1-βKO and IER3IP1-iβKO, respectively. We found that IER3IP1-βKO causes severe early-onset, insulin-deficient diabetes. Functional studies revealed a markedly dilated β-cell ER along with increased proinsulin misfolding and elevated expression of the ER chaperones, including PDI, ERO1, BiP, and P58IPK. Islet transcriptome analysis confirmed by qRT-PCR revealed decreased expression of genes associated with β-cell maturation, cell cycle, and antiapoptotic genes, accompanied by increased expression of antiproliferation genes. Indeed, multiple independent approaches further demonstrated that IER3IP1-βKO impaired β-cell maturation and proliferation, along with increased condensation of β-cell nuclear chromatin. Inducible β-cell IER3IP1 deletion in adult (8-wk-old) mice induced a similar diabetic phenotype, suggesting that IER3IP1 is also critical for function and survival even after β-cell early development. Importantly, IER3IP1 was decreased in β cells of patients with type 2 diabetes (T2D), suggesting an association of IER3IP1 deficiency with β-cell dysfunction in the more-common form of diabetes. These data not only uncover a critical role of IER3IP1 in β cells but also provide insight into molecular basis of diabetes caused by IER3IP1 mutations.
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Affiliation(s)
- Jing Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jinyang Zhen
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Zhenqian Fan
- Department of Endocrinology, The Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xiaoyun Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Hua Shu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jing Xie
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jingting Qiao
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Yuxin Fan
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Na Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Tengli Liu
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, China
- NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, China
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Nankai University, Tianjin 300192, China
- NHC Key Laboratory for Critical Care Medicine, Tianjin First Central Hospital, Tianjin 300384, China
- Human Islet Resource Center, Tianjin First Central Hospital, Tianjin 300384, China
| | - Xiaona Zhang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
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11
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Stefanov BA, Mansouri M, Charpin-El Hamri G, Fussenegger M. Sunlight-Controllable Biopharmaceutical Production for Remote Emergency Supply of Directly Injectable Therapeutic Proteins. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2202566. [PMID: 36084222 DOI: 10.1002/smll.202202566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 08/12/2022] [Indexed: 06/15/2023]
Abstract
Biopharmaceutical manufacturing requires specialized facilities and a long-range cold supply chain for the delivery of the therapeutics to patients. In order to produce biopharmaceuticals in locations lacking such infrastructure, a production process is designed that utilizes the trigger-inducible release of large quantities of a stored therapeutic protein from engineered endocrine cells within minutes to generate a directly injectable saline solution of the protein. To illustrate the versatility of this approach, it is shown that not only insulin, but also glucagon-like peptide 1 (GLP-1), nanoluciferase (NLuc), and the model biopharmaceutical erythropoietin (EPO) can be trigger-inducibly released, even when using biologically inactive insulin as a carrier. The facilitating beta cells are engineered with a controllable TRPV1-mediated Ca2+ influx that induces the fusion of cytoplasmic storage vesicles with the membrane, leading to the release of the stored protein. When required, the growth medium is exchanged for saline solution, and the system is stimulated with the small molecule capsaicin, with a hand-warming pack, or simply by using sunlight. Injection of insulin saline solution obtained in this way into a type-1 diabetes mouse model results in the regulation of blood glucose levels. It is believed that this system will be readily adaptable to deliver various biopharmaceutical proteins at remote locations.
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Affiliation(s)
- Bozhidar-Adrian Stefanov
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Maysam Mansouri
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
| | - Ghislaine Charpin-El Hamri
- Département Génie Biologique, Institut Universitaire de Technologie, Villeurbanne, Cedex F-69622, France
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zürich, Mattenstrasse 26, Basel, 4058, Switzerland
- Faculty of Life Science, University of Basel, Basel, 4058, Switzerland
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12
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Rohli KE, Boyer CK, Bearrows SC, Moyer MR, Elison WS, Bauchle CJ, Blom SE, Zhang J, Wang Y, Stephens SB. ER Redox Homeostasis Regulates Proinsulin Trafficking and Insulin Granule Formation in the Pancreatic Islet β-Cell. FUNCTION 2022; 3:zqac051. [PMID: 36325514 PMCID: PMC9614934 DOI: 10.1093/function/zqac051] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/11/2022] [Accepted: 09/21/2022] [Indexed: 01/07/2023] Open
Abstract
Defects in the pancreatic β-cell's secretion system are well-described in type 2 diabetes (T2D) and include impaired proinsulin processing and a deficit in mature insulin-containing secretory granules; however, the cellular mechanisms underlying these defects remain poorly understood. To address this, we used an in situ fluorescent pulse-chase strategy to study proinsulin trafficking. We show that insulin granule formation and the appearance of nascent granules at the plasma membrane are decreased in rodent and cell culture models of prediabetes and hyperglycemia. Moreover, we link the defect in insulin granule formation to an early trafficking delay in endoplasmic reticulum (ER) export of proinsulin, which is independent of overt ER stress. Using a ratiometric redox sensor, we show that the ER becomes hyperoxidized in β-cells from a dietary model of rodent prediabetes and that addition of reducing equivalents restores ER export of proinsulin and insulin granule formation and partially restores β-cell function. Together, these data identify a critical role for the regulation of ER redox homeostasis in proinsulin trafficking and suggest that alterations in ER redox poise directly contribute to the decline in insulin granule production in T2D. This model highlights a critical link between alterations in ER redox and ER function with defects in proinsulin trafficking in T2D. Hyperoxidation of the ER lumen, shown as hydrogen peroxide, impairs proinsulin folding and disulfide bond formation that prevents efficient exit of proinsulin from the ER to the Golgi. This trafficking defect limits available proinsulin for the formation of insulin secretory granules during the development of T2D.
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Affiliation(s)
- Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Cierra K Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Shelby C Bearrows
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Marshall R Moyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Weston S Elison
- Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, UT 84602, USA
| | - Casey J Bauchle
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Sandra E Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
| | - Jianchao Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48103, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48103, USA
- Department of Neurology, School of Medicine, University of Michigan, Ann Arbor, MI 48103, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa, Iowa City, IA 52242, USA
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13
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Yang ML, Connolly SE, Gee RJ, Lam TT, Kanyo J, Peng J, Guyer P, Syed F, Tse HM, Clarke SG, Clarke CF, James EA, Speake C, Evans-Molina C, Arvan P, Herold KC, Wen L, Mamula MJ. Carbonyl Posttranslational Modification Associated With Early-Onset Type 1 Diabetes Autoimmunity. Diabetes 2022; 71:1979-1993. [PMID: 35730902 PMCID: PMC9450849 DOI: 10.2337/db21-0989] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 06/15/2022] [Indexed: 11/13/2022]
Abstract
Inflammation and oxidative stress in pancreatic islets amplify the appearance of various posttranslational modifications to self-proteins. In this study, we identified a select group of carbonylated islet proteins arising before the onset of hyperglycemia in NOD mice. Of interest, we identified carbonyl modification of the prolyl-4-hydroxylase β subunit (P4Hb) that is responsible for proinsulin folding and trafficking as an autoantigen in both human and murine type 1 diabetes. We found that carbonylated P4Hb is amplified in stressed islets coincident with decreased glucose-stimulated insulin secretion and altered proinsulin-to-insulin ratios. Autoantibodies against P4Hb were detected in prediabetic NOD mice and in early human type 1 diabetes prior to the onset of anti-insulin autoimmunity. Moreover, we identify autoreactive CD4+ T-cell responses toward carbonyl-P4Hb epitopes in the circulation of patients with type 1 diabetes. Our studies provide mechanistic insight into the pathways of proinsulin metabolism and in creating autoantigenic forms of insulin in type 1 diabetes.
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Affiliation(s)
- Mei-Ling Yang
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Sean E. Connolly
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Renelle J. Gee
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
| | - TuKiet T. Lam
- Mass Spectrometry & Proteomics Resource, W.M. Keck Foundation Biotechnology Resource Laboratory, New Haven
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Jean Kanyo
- Mass Spectrometry & Proteomics Resource, W.M. Keck Foundation Biotechnology Resource Laboratory, New Haven
| | - Jian Peng
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Perrin Guyer
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA
| | - Farooq Syed
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
| | - Hubert M. Tse
- Department of Microbiology, Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL
| | - Steven G. Clarke
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA
| | - Catherine F. Clarke
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA
| | - Eddie A. James
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA
| | - Cate Speake
- Center for Interventional Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA
| | - Carmella Evans-Molina
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
| | - Peter Arvan
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Kevan C. Herold
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT
- Department of Immunobiology, Yale University, New Haven, CT
| | - Li Wen
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Mark J. Mamula
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
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14
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Gubas A, Dikic I. ER remodeling via ER-phagy. Mol Cell 2022; 82:1492-1500. [PMID: 35452617 PMCID: PMC9098120 DOI: 10.1016/j.molcel.2022.02.018] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/24/2022] [Accepted: 02/09/2022] [Indexed: 01/01/2023]
Abstract
The endoplasmic reticulum (ER) is a hotspot for many essential cellular functions. The ER membrane is highly dynamic, which affects many cellular processes that take place within the ER. One such process is ER-phagy, a selective degradation of ER fragments (including membranes and luminal content), which serves to preserve the size of ER while adapting its morphology under basal and stress conditions. In order to be degraded, the ER undergoes selective fragmentation facilitated by specialized ER-shaping proteins that also act as ER-phagy receptors. Their ability to sense and induce membrane curvature, as well as to bridge the ER with autophagy machinery, allows for a successful ER fragmentation and delivery of these fragments to the lysosome for degradation and recycling. In this review, we provide insights into ER-phagy from the perspective of membrane remodeling. We highlight the importance of ER membrane dynamics during ER-phagy and emphasize how its dysregulation reflects on human physiology and pathology.
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Affiliation(s)
- Andrea Gubas
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, Frankfurt, Germany.
| | - Ivan Dikic
- Institute of Biochemistry II, Faculty of Medicine, Goethe University Frankfurt, Frankfurt, Germany; Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany; Max Planck Institute of Biophysics, Frankfurt, Germany.
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15
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Dhayalan B, Glidden MD, Zaykov AN, Chen YS, Yang Y, Phillips NB, Ismail-Beigi F, Jarosinski MA, DiMarchi RD, Weiss MA. Peptide Model of the Mutant Proinsulin Syndrome. I. Design and Clinical Correlation. Front Endocrinol (Lausanne) 2022; 13:821069. [PMID: 35299972 PMCID: PMC8922534 DOI: 10.3389/fendo.2022.821069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/17/2022] [Indexed: 12/16/2022] Open
Abstract
The mutant proinsulin syndrome is a monogenic cause of diabetes mellitus due to toxic misfolding of insulin's biosynthetic precursor. Also designated mutant INS-gene induced diabetes of the young (MIDY), this syndrome defines molecular determinants of foldability in the endoplasmic reticulum (ER) of β-cells. Here, we describe a peptide model of a key proinsulin folding intermediate and variants containing representative clinical mutations; the latter perturb invariant core sites in native proinsulin (LeuB15→Pro, LeuA16→Pro, and PheB24→Ser). The studies exploited a 49-residue single-chain synthetic precursor (designated DesDi), previously shown to optimize in vitro efficiency of disulfide pairing. Parent and variant peptides contain a single disulfide bridge (cystine B19-A20) to provide a model of proinsulin's first oxidative folding intermediate. The peptides were characterized by circular dichroism and redox stability in relation to effects of the mutations on (a) in vitro foldability of the corresponding insulin analogs and (b) ER stress induced in cell culture on expression of the corresponding variant proinsulins. Striking correlations were observed between peptide biophysical properties, degree of ER stress and age of diabetes onset (neonatal or adolescent). Our findings suggest that age of onset reflects the extent to which nascent structure is destabilized in proinsulin's putative folding nucleus. We envisage that such peptide models will enable high-resolution structural studies of key folding determinants and in turn permit molecular dissection of phenotype-genotype relationships in this monogenic diabetes syndrome. Our companion study (next article in this issue) employs two-dimensional heteronuclear NMR spectroscopy to define site-specific perturbations in the variant peptides.
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Affiliation(s)
- Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Michael D. Glidden
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | | | - Yen-Shan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Yanwu Yang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Nelson B. Phillips
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Faramarz Ismail-Beigi
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Mark A. Jarosinski
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
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16
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Yang Y, Glidden MD, Dhayalan B, Zaykov AN, Chen YS, Wickramasinghe NP, DiMarchi RD, Weiss MA. Peptide Model of the Mutant Proinsulin Syndrome. II. Nascent Structure and Biological Implications. Front Endocrinol (Lausanne) 2022; 13:821091. [PMID: 35299958 PMCID: PMC8922542 DOI: 10.3389/fendo.2022.821091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022] Open
Abstract
Toxic misfolding of proinsulin variants in β-cells defines a monogenic diabetes syndrome, designated mutant INS-gene induced diabetes of the young (MIDY). In our first study (previous article in this issue), we described a one-disulfide peptide model of a proinsulin folding intermediate and its use to study such variants. The mutations (LeuB15→Pro, LeuA16→Pro, and PheB24→Ser) probe residues conserved among vertebrate insulins. In this companion study, we describe 1H and 1H-13C NMR studies of the peptides; key NMR resonance assignments were verified by synthetic 13C-labeling. Parent spectra retain nativelike features in the neighborhood of the single disulfide bridge (cystine B19-A20), including secondary NMR chemical shifts and nonlocal nuclear Overhauser effects. This partial fold engages wild-type side chains LeuB15, LeuA16 and PheB24 at the nexus of nativelike α-helices α1 and α3 (as defined in native proinsulin) and flanking β-strand (residues B24-B26). The variant peptides exhibit successive structural perturbations in order: parent (most organized) > SerB24 >> ProA16 > ProB15 (least organized). The same order pertains to (a) overall α-helix content as probed by circular dichroism, (b) synthetic yields of corresponding three-disulfide insulin analogs, and (c) ER stress induced in cell culture by corresponding mutant proinsulins. These findings suggest that this and related peptide models will provide a general platform for classification of MIDY mutations based on molecular mechanisms by which nascent disulfide pairing is impaired. We propose that the syndrome's variable phenotypic spectrum-onsets ranging from the neonatal period to later in childhood or adolescence-reflects structural features of respective folding intermediates.
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Affiliation(s)
- Yanwu Yang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Michael D. Glidden
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | | | - Yen-Shan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Nalinda P. Wickramasinghe
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | | | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
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17
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Dhayalan B, Weiss MA. Diabetes-Associated Mutations in Proinsulin Provide a "Molecular Rheostat" of Nascent Foldability. Curr Diab Rep 2022; 22:85-94. [PMID: 35119630 DOI: 10.1007/s11892-022-01447-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/04/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE OF REVIEW Diabetes mellitus (DM) due to toxic misfolding of proinsulin variants provides a monogenic model of endoplasmic reticulum (ER) stress. The mutant proinsulin syndrome (also designated MIDY; Mutant INS-gene-induced Diabetes of Youth or Maturity-onset diabetes of the young 10 (MODY10)) ordinarily presents as permanent neonatal-onset DM, but specific amino-acid substitutions may also present later in childhood or adolescence. This review highlights structural mechanisms of proinsulin folding as inferred from phenotype-genotype relationships. RECENT FINDINGS MIDY mutations most commonly add or remove a cysteine, leading to a variant polypeptide containing an odd number of thiol groups. Such variants are associated with aberrant intermolecular disulfide pairing, ER stress, and neonatal β-cell dysfunction. Non-cysteine-related (NCR) mutations (occurring in both the B and A domains of proinsulin) define distinct determinants of foldability and vary in severity. The range of ages of onset, therefore, reflects a "molecular rheostat" connecting protein biophysics to quality-control ER checkpoints. Because in most mammalian cell lines even wild-type proinsulin exhibits limited folding efficiency, molecular barriers to folding uncovered by NCR MIDY mutations may pertain to β-cell dysfunction in non-syndromic type 2 DM due to INS-gene overexpression in the face of peripheral insulin resistance. Recent studies of MIDY mutations and related NCR variants, combining molecular and cell-based approaches, suggest that proinsulin has evolved at the edge of non-foldability. Chemical protein synthesis promises to enable comparative studies of "non-foldable" proinsulin variants to define key steps in wild-type biosynthesis. Such studies may create opportunities for novel therapeutic approaches to non-syndromic type 2 DM.
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Affiliation(s)
- Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Department of Chemistry, Indiana University, Bloomington, IN, 47405, USA.
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
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18
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Amirruddin NS, Tan WX, Tan YS, Gardner DSL, Bee YM, Verma CS, Hoon S, Lee KO, Teo AKK. Progressive endoplasmic reticulum stress over time due to human insulin gene mutation contributes to pancreatic beta cell dysfunction. Diabetologia 2021; 64:2534-2549. [PMID: 34448879 DOI: 10.1007/s00125-021-05530-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 05/14/2021] [Indexed: 10/20/2022]
Abstract
AIMS/HYPOTHESIS We studied the effects of heterozygous human INS gene mutations on insulin secretion, endoplasmic reticulum (ER) stress and other mechanisms in both MIN6 and human induced pluripotent stem cells (hiPSC)-derived beta-like cells, as well as the effects of prolonged overexpression of mutant human INS in MIN6 cells. METHODS We modelled the structure of mutant C109Y and G32V proinsulin computationally to examine the in silico effects. We then overexpressed either wild-type (WT), mutant (C109Y or G32V), or both WT and mutant human preproinsulin in MIN6 cells, both transiently and stably over several weeks. We measured the levels of human and rodent insulin secreted, and examined the transcript and protein levels of several ER stress and apoptotic markers. We also reprogrammed human donor fibroblasts heterozygous for the C109Y mutation into hiPSCs and differentiated these into pancreatic beta-like cells, which were subjected to single-cell RNA-sequencing and transcript and protein analyses for ER stress and apoptotic markers. RESULTS The computational modelling studies, and short-term and long-term expression studies in beta cells, revealed the presence of ER stress, organelle changes and insulin processing defects, resulting in a decreased amount of insulin secreted but not the ability to secrete insulin. By 9 weeks of expression of mutant human INS, dominant-negative effects of mutant INS were evident and beta cell insulin secretory capacity declined. INS+/C109Y patient-derived beta-like cells and single-cell RNA-sequencing analyses then revealed compensatory upregulation in genes involved in insulin secretion, processing and inflammatory response. CONCLUSIONS/INTERPRETATION The results provide deeper insights into the mechanisms of beta cell failure during INS mutation-mediated diabetes disease progression. Decreasing spliced X-box binding protein 1 (sXBP1) or inflammatory response could be avenues to restore the function of the remaining WT INS allele.
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Affiliation(s)
- Nur Shabrina Amirruddin
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Wei Xuan Tan
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Yaw Sing Tan
- Bioinformatics Institute, A*STAR, Singapore, Republic of Singapore
| | - Daphne Su-Lyn Gardner
- Department of Endocrinology, Singapore General Hospital, Singapore, Republic of Singapore
| | - Yong Mong Bee
- Department of Endocrinology, Singapore General Hospital, Singapore, Republic of Singapore
| | - Chandra Shekhar Verma
- Bioinformatics Institute, A*STAR, Singapore, Republic of Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Republic of Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Republic of Singapore
| | - Shawn Hoon
- Molecular Engineering Laboratory, IMCB, A*STAR, Singapore, Republic of Singapore
| | - Kok Onn Lee
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore
| | - Adrian Kee Keong Teo
- Stem Cells and Diabetes Laboratory, Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), Singapore, Republic of Singapore.
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore.
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Republic of Singapore.
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19
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PGRMC1 acts as a size-selective cargo receptor to drive ER-phagic clearance of mutant prohormones. Nat Commun 2021; 12:5991. [PMID: 34645803 PMCID: PMC8514460 DOI: 10.1038/s41467-021-26225-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 09/20/2021] [Indexed: 02/06/2023] Open
Abstract
The reticulon-3 (RTN3)-driven targeting complex promotes clearance of misfolded prohormones from the endoplasmic reticulum (ER) for lysosomal destruction by ER-phagy. Because RTN3 resides in the cytosolic leaflet of the ER bilayer, the mechanism of selecting misfolded prohormones as ER-phagy cargo on the luminal side of the ER membrane remains unknown. Here we identify the ER transmembrane protein PGRMC1 as an RTN3-binding partner. Via its luminal domain, PGRMC1 captures misfolded prohormones, targeting them for RTN3-dependent ER-phagy. PGRMC1 selects cargos that are smaller than the large size of other reported ER-phagy substrates. Cargos for PGRMC1 include mutant proinsulins that block secretion of wildtype proinsulin through dominant-negative interactions within the ER, causing insulin-deficiency. Chemical perturbation of PGRMC1 partially restores WT insulin storage by preventing ER-phagic degradation of WT and mutant proinsulin. Thus, PGRMC1 acts as a size-selective cargo receptor during RTN3-dependent ER-phagy, and is a potential therapeutic target for diabetes.
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20
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Herlea-Pana O, Eeda V, Undi RB, Lim HY, Wang W. Pharmacological Inhibition of Inositol-Requiring Enzyme 1α RNase Activity Protects Pancreatic Beta Cell and Improves Diabetic Condition in Insulin Mutation-Induced Diabetes. Front Endocrinol (Lausanne) 2021; 12:749879. [PMID: 34675883 PMCID: PMC8524045 DOI: 10.3389/fendo.2021.749879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 12/25/2022] Open
Abstract
β-cell ER stress plays an important role in β-cell dysfunction and death during the pathogenesis of diabetes. Proinsulin misfolding is regarded as one of the primary initiating factors of ER stress and unfolded protein response (UPR) activation in β-cells. Here, we found that the ER stress sensor inositol-requiring enzyme 1α (IRE1α) was activated in the Akita mice, a mouse model of mutant insulin gene-induced diabetes of youth (MIDY), a monogenic diabetes. Normalization of IRE1α RNase hyperactivity by pharmacological inhibitors significantly ameliorated the hyperglycemic conditions and increased serum insulin levels in Akita mice. These benefits were accompanied by a concomitant protection of functional β-cell mass, as shown by the suppression of β-cell apoptosis, increase in mature insulin production and reduction of proinsulin level. At the molecular level, we observed that the expression of genes associated with β-cell identity and function was significantly up-regulated and ER stress and its associated inflammation and oxidative stress were suppressed in islets from Akita mice treated with IRE1α RNase inhibitors. This study provides the evidence of the in vivo efficacy of IRE1α RNase inhibitors in Akita mice, pointing to the possibility of targeting IRE1α RNase as a therapeutic direction for the treatment of diabetes.
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Affiliation(s)
- Oana Herlea-Pana
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
| | - Venkateswararao Eeda
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
| | - Ram Babu Undi
- Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Hui-Ying Lim
- Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Weidong Wang
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
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21
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Dhayalan B, Chatterjee D, Chen YS, Weiss MA. Structural Lessons From the Mutant Proinsulin Syndrome. Front Endocrinol (Lausanne) 2021; 12:754693. [PMID: 34659132 PMCID: PMC8514764 DOI: 10.3389/fendo.2021.754693] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/13/2021] [Indexed: 12/30/2022] Open
Abstract
Insight into folding mechanisms of proinsulin has been provided by analysis of dominant diabetes-associated mutations in the human insulin gene (INS). Such mutations cause pancreatic β-cell dysfunction due to toxic misfolding of a mutant proinsulin and impairment in trans of wild-type insulin secretion. Anticipated by the "Akita" mouse (a classical model of monogenic diabetes mellitus; DM), this syndrome illustrates the paradigm endoreticulum (ER) stress leading to intracellular proteotoxicity. Diverse clinical mutations directly or indirectly perturb native disulfide pairing leading to protein misfolding and aberrant aggregation. Although most introduce or remove a cysteine (Cys; leading in either case to an unpaired thiol group), non-Cys-related mutations identify key determinants of folding efficiency. Studies of such mutations suggest that the hormone's evolution has been constrained not only by structure-function relationships, but also by the susceptibility of its single-chain precursor to impaired foldability. An intriguing hypothesis posits that INS overexpression in response to peripheral insulin resistance likewise leads to chronic ER stress and β-cell dysfunction in the natural history of non-syndromic Type 2 DM. Cryptic contributions of conserved residues to folding efficiency, as uncovered by rare genetic variants, define molecular links between biophysical principles and the emerging paradigm of Darwinian medicine: Biosynthesis of proinsulin at the edge of non-foldability provides a key determinant of "diabesity" as a pandemic disease of civilization.
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Affiliation(s)
| | | | | | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
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22
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Parashar S, Chidambaram R, Chen S, Liem CR, Griffis E, Lambert GG, Shaner NC, Wortham M, Hay JC, Ferro-Novick S. Endoplasmic reticulum tubules limit the size of misfolded protein condensates. eLife 2021; 10:e71642. [PMID: 34467852 PMCID: PMC8486381 DOI: 10.7554/elife.71642] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/31/2021] [Indexed: 12/19/2022] Open
Abstract
The endoplasmic reticulum (ER) is composed of sheets and tubules. Here we report that the COPII coat subunit, SEC24C, works with the long form of the tubular ER-phagy receptor, RTN3, to target dominant-interfering mutant proinsulin Akita puncta to lysosomes. When the delivery of Akita puncta to lysosomes was disrupted, large puncta accumulated in the ER. Unexpectedly, photobleach analysis indicated that Akita puncta behaved as condensates and not aggregates, as previously suggested. Akita puncta enlarged when either RTN3 or SEC24C were depleted, or when ER sheets were proliferated by either knocking out Lunapark or overexpressing CLIMP63. Other ER-phagy substrates that are segregated into tubules behaved like Akita, while a substrate (type I procollagen) that is degraded by the ER-phagy sheets receptor, FAM134B, did not. Conversely, when ER tubules were augmented in Lunapark knock-out cells by overexpressing reticulons, ER-phagy increased and the number of large Akita puncta was reduced. Our findings imply that segregating cargoes into tubules has two beneficial roles. First, it localizes mutant misfolded proteins, the receptor, and SEC24C to the same ER domain. Second, physically restraining condensates within tubules, before they undergo ER-phagy, prevents them from enlarging and impacting cell health.
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Affiliation(s)
- Smriti Parashar
- Department of Cellular and Molecular Medicine, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Ravi Chidambaram
- Department of Cellular and Molecular Medicine, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Shuliang Chen
- Department of Cellular and Molecular Medicine, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Christina R Liem
- Division of Biological Sciences, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Eric Griffis
- Nikon Imaging Center, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Gerard G Lambert
- Department of Neurosciences, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Nathan C Shaner
- Department of Neurosciences, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Matthew Wortham
- Department of Pediatrics, Pediatric Diabetes Research Center, University of California at San DiegoLa Jolla, CaliforniaUnited States
| | - Jesse C Hay
- Division of Biological Sciences and Center for Structural & Functional Neuroscience, University of MontanaMissoulaUnited States
| | - Susan Ferro-Novick
- Department of Cellular and Molecular Medicine, University of California at San DiegoLa Jolla, CaliforniaUnited States
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23
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Huang Y, Xu X, Arvan P, Liu M. Deficient endoplasmic reticulum translocon-associated protein complex limits the biosynthesis of proinsulin and insulin. FASEB J 2021; 35:e21515. [PMID: 33811688 DOI: 10.1096/fj.202002774r] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/14/2021] [Accepted: 02/24/2021] [Indexed: 01/22/2023]
Abstract
The conserved endoplasmic reticulum (ER) membrane protein TRAPα (translocon-associated protein, also known as signal sequence receptor 1, SSR1) has been reported to play a critical but unclear role in insulin biosynthesis. TRAPα/SSR1 is one component of a four-protein complex including TRAPβ/SSR2, TRAPγ/SSR3, and TRAPδ/SSR4. The TRAP complex topologically has a small exposure on the cytosolic side of the ER via its TRAPγ/SSR3 subunit, whereas TRAPβ/SSR2 and TRAPδ/SSR4 function along with TRAPα/SSR1 largely on the luminal side of the ER membrane. Here, we have examined pancreatic β-cells with deficient expression of either TRAPβ/SSR2 or TRAPδ/SSR4, which does not perturb mRNA expression levels of other TRAP subunits, or insulin mRNA. However, deficient protein expression of TRAPβ/SSR2 and, to a lesser degree, TRAPδ/SSR4, diminishes the protein levels of other TRAP subunits, concomitant with deficient steady-state levels of proinsulin and insulin. Deficient TRAPβ/SSR2 or TRAPδ/SSR4 is not associated with any apparent defect of exocytotic mechanism but rather by a decreased abundance of the proinsulin and insulin that accompanies glucose-stimulated secretion. Amino acid pulse labeling directly establishes that much of the steady-state deficiency of intracellular proinsulin can be accounted for by diminished proinsulin biosynthesis, observed in a pulse-labeling as short as 5 minutes. The proinsulin and insulin levels in TRAPβ/SSR2 or TRAPδ/SSR4 null mutant β-cells are notably recovered upon re-expression of the missing TRAP subunit, accompanying a rebound of proinsulin biosynthesis. Remarkably, overexpression of TRAPα/SSR1 can also suppress defects in β-cells with diminished expression of TRAPβ/SSR2, strongly suggesting that TRAPβ/SSR2 is needed to support TRAPα/SSR1 function.
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Affiliation(s)
- Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.,Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.,Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.,Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, USA
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24
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Haataja L, Arunagiri A, Hassan A, Regan K, Tsai B, Dhayalan B, Weiss MA, Liu M, Arvan P. Distinct states of proinsulin misfolding in MIDY. Cell Mol Life Sci 2021; 78:6017-6031. [PMID: 34245311 PMCID: PMC8316239 DOI: 10.1007/s00018-021-03871-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/17/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022]
Abstract
A precondition for efficient proinsulin export from the endoplasmic reticulum (ER) is that proinsulin meets ER quality control folding requirements, including formation of the Cys(B19)–Cys(A20) “interchain” disulfide bond, facilitating formation of the Cys(B7)–Cys(A7) bridge. The third proinsulin disulfide, Cys(A6)–Cys(A11), is not required for anterograde trafficking, i.e., a “lose-A6/A11” mutant [Cys(A6), Cys(A11) both converted to Ser] is well secreted. Nevertheless, an unpaired Cys(A11) can participate in disulfide mispairings, causing ER retention of proinsulin. Among the many missense mutations causing the syndrome of Mutant INS gene-induced Diabetes of Youth (MIDY), all seem to exhibit perturbed proinsulin disulfide bond formation. Here, we have examined a series of seven MIDY mutants [including G(B8)V, Y(B26)C, L(A16)P, H(B5)D, V(B18)A, R(Cpep + 2)C, E(A4)K], six of which are essentially completely blocked in export from the ER in pancreatic β-cells. Three of these mutants, however, must disrupt the Cys(A6)–Cys(A11) pairing to expose a critical unpaired cysteine thiol perturbation of proinsulin folding and ER export, because when introduced into the proinsulin lose-A6/A11 background, these mutants exhibit native-like disulfide bonding and improved trafficking. This maneuver also ameliorates dominant-negative blockade of export of co-expressed wild-type proinsulin. A growing molecular understanding of proinsulin misfolding may permit allele-specific pharmacological targeting for some MIDY mutants.
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Affiliation(s)
- Leena Haataja
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Anoop Arunagiri
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Anis Hassan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Kaitlin Regan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University, Indianapolis, IN, 46202, USA
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University, Indianapolis, IN, 46202, USA
| | - Ming Liu
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, 300052, China
| | - Peter Arvan
- The Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, MI, 48105, USA.
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25
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Morishita Y, Kellogg AP, Larkin D, Chen W, Vadrevu S, Satin L, Liu M, Arvan P. Cell death-associated lipid droplet protein CIDE-A is a noncanonical marker of endoplasmic reticulum stress. JCI Insight 2021; 6:143980. [PMID: 33661766 PMCID: PMC8119190 DOI: 10.1172/jci.insight.143980] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 03/02/2021] [Indexed: 01/05/2023] Open
Abstract
Secretory protein misfolding has been linked to ER stress and cell death. We expressed a TGrdw transgene encoding TG-G(2298)R, a misfolded mutant thyroglobulin reported to be linked to thyroid cell death. When the TGrdw transgene was expressed at low level in thyrocytes of TGcog/cog mice that experienced severe ER stress, we observed increased thyrocyte cell death and increased expression of CIDE-A (cell death-inducing DFFA-like effector-A, a protein of lipid droplets) in whole thyroid gland. Here we demonstrate that acute ER stress in cultured PCCL3 thyrocytes increases Cidea mRNA levels, maintained at least in part by increased mRNA stability, while being negatively regulated by activating transcription factor 6 - with similar observations that ER stress increases Cidea mRNA levels in other cell types. CIDE-A protein is sensitive to proteasomal degradation yet is stabilized by ER stress, and elevated expression levels accompany increased cell death. Unlike acute ER stress, PCCL3 cells adapted and surviving chronic ER stress maintained a disproportionately lower relative mRNA level of Cidea compared with that of other, classical ER stress markers, as well as a blunted Cidea mRNA response to a new, unrelated acute ER stress challenge. We suggest that CIDE-A is a novel marker linked to a noncanonical ER stress response program, with implications for cell death and survival.
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Affiliation(s)
- Yoshiaki Morishita
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University, Aichi, Japan
| | - Aaron P. Kellogg
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Dennis Larkin
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Wei Chen
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Suryakiran Vadrevu
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Leslie Satin
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pharmacology, University of Michigan Medical Center, Ann Arbor, Michigan, USA
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Endocrinology & Diabetes, Tianjin Medical University, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
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26
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Dhayalan B, Chatterjee D, Chen YS, Weiss MA. Diabetes mellitus due to toxic misfolding of proinsulin variants. Mol Metab 2021:101229. [PMID: 33823319 DOI: 10.1016/j.molmet.2021.101229] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/10/2021] [Accepted: 03/29/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Dominant mutations in the human insulin gene (INS) lead to pancreatic β-cell dysfunction and diabetes mellitus (DM) due to toxic misfolding of a mutant proinsulin. Analogous to a classical mouse model of monogenic DM ("Akita"), this syndrome highlights the susceptibility of β-cells to endoreticulum (ER) stress due to protein misfolding and aberrant aggregation. SCOPE OF REVIEW Diverse clinical mutations directly or indirectly perturb native disulfide pairing. Whereas most introduce or remove a cysteine (Cys; leading in either case to an unpaired thiol group), non-Cys-related mutations identify key determinants of folding efficiency. Studies of such mutations suggest that the hormone's evolution has been constrained not only by structure-function relationships but also by the susceptibility of its single-chain precursor to impaired foldability. An intriguing hypothesis posits that INS overexpression in response to peripheral insulin resistance likewise leads to chronic ER stress and β-cell dysfunction in the natural history of nonsyndromic Type 2 DM. MAJOR CONCLUSIONS Cryptic contributions of conserved residues to folding efficiency, as uncovered by rare genetic variants, define molecular links between biophysical principles and the emerging paradigm of Darwinian medicine: Biosynthesis of proinsulin at the edge of nonfoldability provides a key determinant of "diabesity" as a pandemic disease of civilization.
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Affiliation(s)
- Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Deepak Chatterjee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Yen-Shan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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27
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Kambe T, Taylor KM, Fu D. Zinc transporters and their functional integration in mammalian cells. J Biol Chem 2021; 296:100320. [PMID: 33485965 PMCID: PMC7949119 DOI: 10.1016/j.jbc.2021.100320] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 01/15/2021] [Accepted: 01/20/2021] [Indexed: 12/14/2022] Open
Abstract
Zinc is a ubiquitous biological metal in all living organisms. The spatiotemporal zinc dynamics in cells provide crucial cellular signaling opportunities, but also challenges for intracellular zinc homeostasis with broad disease implications. Zinc transporters play a central role in regulating cellular zinc balance and subcellular zinc distributions. The discoveries of two complementary families of mammalian zinc transporters (ZnTs and ZIPs) in the mid-1990s spurred much speculation on their metal selectivity and cellular functions. After two decades of research, we have arrived at a biochemical description of zinc transport. However, in vitro functions are fundamentally different from those in living cells, where mammalian zinc transporters are directed to specific subcellular locations, engaged in dedicated macromolecular machineries, and connected with diverse cellular processes. Hence, the molecular functions of individual zinc transporters are reshaped and deeply integrated in cells to promote the utilization of zinc chemistry to perform enzymatic reactions, tune cellular responsiveness to pathophysiologic signals, and safeguard cellular homeostasis. At present, the underlying mechanisms driving the functional integration of mammalian zinc transporters are largely unknown. This knowledge gap has motivated a shift of the research focus from in vitro studies of purified zinc transporters to in cell studies of mammalian zinc transporters in the context of their subcellular locations and protein interactions. In this review, we will outline how knowledge of zinc transporters has been accumulated from in-test-tube to in-cell studies, highlighting new insights and paradigm shifts in our understanding of the molecular and cellular basis of mammalian zinc transporter functions.
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Affiliation(s)
- Taiho Kambe
- Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Kathryn M Taylor
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Dax Fu
- Department of Physiology, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.
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28
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Liu M, Huang Y, Xu X, Li X, Alam M, Arunagiri A, Haataja L, Ding L, Wang S, Itkin-Ansari P, Kaufman RJ, Tsai B, Qi L, Arvan P. Normal and defective pathways in biogenesis and maintenance of the insulin storage pool. J Clin Invest 2021; 131:142240. [PMID: 33463547 PMCID: PMC7810482 DOI: 10.1172/jci142240] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Both basal and glucose-stimulated insulin release occur primarily by insulin secretory granule exocytosis from pancreatic β cells, and both are needed to maintain normoglycemia. Loss of insulin-secreting β cells, accompanied by abnormal glucose tolerance, may involve simple exhaustion of insulin reserves (which, by immunostaining, appears as a loss of β cell identity), or β cell dedifferentiation, or β cell death. While various sensing and signaling defects can result in diminished insulin secretion, somewhat less attention has been paid to diabetes risk caused by insufficiency in the biosynthetic generation and maintenance of the total insulin granule storage pool. This Review offers an overview of insulin biosynthesis, beginning with the preproinsulin mRNA (translation and translocation into the ER), proinsulin folding and export from the ER, and delivery via the Golgi complex to secretory granules for conversion to insulin and ultimate hormone storage. All of these steps are needed for generation and maintenance of the total insulin granule pool, and defects in any of these steps may, weakly or strongly, perturb glycemic control. The foregoing considerations have obvious potential relevance to the pathogenesis of type 2 diabetes and some forms of monogenic diabetes; conceivably, several of these concepts might also have implications for β cell failure in type 1 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Maroof Alam
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Tianjin, China
| | | | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, and
| | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
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29
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Yang Y, Shu H, Hu J, Li L, Wang J, Chen T, Zhen J, Sun J, Feng W, Xiong Y, Huang Y, Li X, Zhang K, Fan Z, Guo H, Liu M. A Novel Nonsense INS Mutation Causes Inefficient Preproinsulin Translocation Into the Endoplasmic Reticulum. Front Endocrinol (Lausanne) 2021; 12:774634. [PMID: 35069438 PMCID: PMC8769375 DOI: 10.3389/fendo.2021.774634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Preproinsulin (PPI) translocation across the membrane of the endoplasmic reticulum (ER) is the first and critical step of insulin biosynthesis. Inefficient PPI translocation caused by signal peptide (SP) mutations can lead to β-cell failure and diabetes. However, the effect of proinsulin domain on the efficiency of PPI translocation remains unknown. With whole exome sequencing, we identified a novel INS nonsense mutation resulting in an early termination at the 46th residue of PPI (PPI-R46X) in two unrelated patients with early-onset diabetes. We examined biological behaviors of the mutant and compared them to that of an established neonatal diabetes causing mutant PPI-C96Y. Although both mutants were retained in the cells, unlike C96Y, R46X did not induce ER stress or form abnormal disulfide-linked proinsulin complexes. More importantly, R46X did not interact with co-expressed wild-type (WT) proinsulin in the ER, and did not impair proinsulin-WT folding, trafficking, and insulin production. Metabolic labeling experiments established that, despite with an intact SP, R46X failed to be efficiently translocated into the ER, suggesting that proinsulin domain downstream of SP plays an important unrecognized role in PPI translocation across the ER membrane. The study not only expends the list of INS mutations associated with diabetes, but also provides genetic and biological evidence underlying the regulation mechanism of PPI translocation.
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Affiliation(s)
- Ying Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Hua Shu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingxin Hu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Lei Li
- Department of Endocrinology, The Second Part of Jilin University First Hospital, Jilin, China
| | - Jianyu Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Tingting Chen
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinyang Zhen
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yi Xiong
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Kai Zhang
- Department of Technology Services, RSR Tianjin Biotech Co., Tianjin, China
| | - Zhenqian Fan
- Department of Endocrinology and Metabolism, The Second Hospital of Tianjin Medical University, Tianjin, China
- *Correspondence: Ming Liu, ; Zhenqian Fan, ; Hui Guo,
| | - Hui Guo
- Department of Endocrinology, The Second Part of Jilin University First Hospital, Jilin, China
- *Correspondence: Ming Liu, ; Zhenqian Fan, ; Hui Guo,
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- *Correspondence: Ming Liu, ; Zhenqian Fan, ; Hui Guo,
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Wang H, Saint-Martin C, Xu J, Ding L, Wang R, Feng W, Liu M, Shu H, Fan Z, Haataja L, Arvan P, Bellanné-Chantelot C, Cui J, Huang Y. Biological behaviors of mutant proinsulin contribute to the phenotypic spectrum of diabetes associated with insulin gene mutations. Mol Cell Endocrinol 2020; 518:111025. [PMID: 32916194 PMCID: PMC7734662 DOI: 10.1016/j.mce.2020.111025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 02/06/2023]
Abstract
Insulin gene mutation is the second most common cause of neonatal diabetes (NDM). It is also one of the genes involved in maturity-onset diabetes of the young (MODY). We aim to investigate molecular behaviors of different INS gene variants that may correlate with the clinical spectrum of diabetes phenotypes. In this study, we concentrated on two previously uncharacterized MODY-causing mutants, proinsulin-p.Gly44Arg [G(B20)R] and p.Pro52Leu [P(B28)L] (a novel mutant identified in one French family), and an NDM causing proinsulin-p.(Cys96Tyr) [C(A7)Y]. We find that these proinsulin mutants exhibit impaired oxidative folding in the endoplasmic reticulum (ER) with blocked ER export, ER stress, and apoptosis. Importantly, the proinsulin mutants formed abnormal intermolecular disulfide bonds that not only involved the mutant proinsulin, but also the co-expressed WT-proinsulin, forming misfolded disulfide-linked proinsulin complexes. This impaired the intracellular trafficking of WT-proinsulin and limited the production of bioactive mature insulin. Notably, although all three mutants presented with similar defects in folding, trafficking, and dominant negative behavior, the degrees of these defects appeared to be different. Specifically, compared to MODY mutants G(B20)R and P(B28)L that partially affected folding and trafficking of co-expressed WT-proinsulin, the NDM mutant C(A7)Y resulted in an almost complete blockade of the ER export of WT-proinsulin, decreasing insulin production, inducing more severe ER stress and apoptosis. We thus demonstrate that differences in cell biological behaviors among different proinsulin mutants correlate with the spectrum of diabetes phenotypes caused by the different INS gene mutations.
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Affiliation(s)
- Heting Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Cécile Saint-Martin
- Department of Genetics, Sorbonne University, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Jialu Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ruodan Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China; Tianjin Institute of Endocrinology, Tianjin, China
| | - Hua Shu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Zhenqian Fan
- Department of Endocrinology and Metabolism, The Second Hospital of Tianjin Medical University, Tianjin, China
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Christine Bellanné-Chantelot
- Department of Genetics, Sorbonne University, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
| | - Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China.
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Austin ALF, Daniels Gatward LF, Cnop M, Santos G, Andersson D, Sharp S, Gentry C, Bevan S, Jones PM, King AJF. The KINGS Ins2 +/G32S Mouse: A Novel Model of β-Cell Endoplasmic Reticulum Stress and Human Diabetes. Diabetes 2020; 69:2667-2677. [PMID: 32994272 PMCID: PMC7679781 DOI: 10.2337/db20-0570] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 09/21/2020] [Indexed: 02/06/2023]
Abstract
Animal models are important tools in diabetes research because ethical and logistical constraints limit access to human tissue. β-Cell dysfunction is a common contributor to the pathogenesis of most types of diabetes. Spontaneous hyperglycemia was developed in a colony of C57BL/6J mice at King's College London (KCL). Sequencing identified a mutation in the Ins2 gene, causing a glycine-to-serine substitution at position 32 on the B chain of the preproinsulin 2 molecule. Mice with the Ins2 +/G32S mutation were named KCL Ins2 G32S (KINGS) mice. The same mutation in humans (rs80356664) causes dominantly inherited neonatal diabetes. Mice were characterized, and β-cell function was investigated. Male mice became overtly diabetic at ∼5 weeks of age, whereas female mice had only slightly elevated nonfasting glycemia. Islets showed decreased insulin content and impaired glucose-induced insulin secretion, which was more severe in males. Transmission electron microscopy and studies of gene and protein expression showed β-cell endoplasmic reticulum (ER) stress in both sexes. Despite this, β-cell numbers were only slightly reduced in older animals. In conclusion, the KINGS mouse is a novel model of a human form of diabetes that may be useful to study β-cell responses to ER stress.
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Affiliation(s)
- Amazon L F Austin
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | | | - Miriam Cnop
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
- Division of Endocrinology, ULB Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Gabriel Santos
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | - David Andersson
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Sally Sharp
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Clive Gentry
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Stuart Bevan
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, U.K
| | - Peter M Jones
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | - Aileen J F King
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K.
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Rege NK, Liu M, Yang Y, Dhayalan B, Wickramasinghe NP, Chen YS, Rahimi L, Guo H, Haataja L, Sun J, Ismail-Beigi F, Phillips NB, Arvan P, Weiss MA. Evolution of insulin at the edge of foldability and its medical implications. Proc Natl Acad Sci U S A 2020; 117:29618-29628. [PMID: 33154160 PMCID: PMC7703552 DOI: 10.1073/pnas.2010908117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Proteins have evolved to be foldable, and yet determinants of foldability may be inapparent once the native state is reached. Insight has emerged from studies of diseases of protein misfolding, exemplified by monogenic diabetes mellitus due to mutations in proinsulin leading to endoplasmic reticulum stress and β-cell death. Cellular foldability of human proinsulin requires an invariant Phe within a conserved crevice at the receptor-binding surface (position B24). Any substitution, even related aromatic residue TyrB24, impairs insulin biosynthesis and secretion. As a seeming paradox, a monomeric TyrB24 insulin analog exhibits a native-like structure in solution with only a modest decrement in stability. Packing of TyrB24 is similar to that of PheB24, adjoining core cystine B19-A20 to seal the core; the analog also exhibits native self-assembly. Although affinity for the insulin receptor is decreased ∼20-fold, biological activities in cells and rats were within the range of natural variation. Together, our findings suggest that the invariance of PheB24 among vertebrate insulins and insulin-like growth factors reflects an essential role in enabling efficient protein folding, trafficking, and secretion, a function that is inapparent in native structures. In particular, we envision that the para-hydroxyl group of TyrB24 hinders pairing of cystine B19-A20 in an obligatory on-pathway folding intermediate. The absence of genetic variation at B24 and other conserved sites near this disulfide bridge-excluded due to β-cell dysfunction-suggests that insulin has evolved to the edge of foldability. Nonrobustness of a protein's fitness landscape underlies both a rare monogenic syndrome and "diabesity" as a pandemic disease of civilization.
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Affiliation(s)
- Nischay K Rege
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, 300052 Tianjin, China
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Yanwu Yang
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Balamurugan Dhayalan
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | | | - Yen-Shan Chen
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Leili Rahimi
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106
| | - Huan Guo
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Jinhong Sun
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Faramarz Ismail-Beigi
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106
| | - Nelson B Phillips
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105
| | - Michael A Weiss
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106;
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
- Department of Medicine, Case Western Reserve University, Cleveland, OH 44106
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Demiral M, Demirbilek H, Çelik K, Okur N, Hussain K, Ozbek MN. Neonatal diabetes due to homozygous INS gene promoter mutations: Highly variable phenotype, remission and early relapse during the first 3 years of life. Pediatr Diabetes 2020; 21:1169-1175. [PMID: 32656923 DOI: 10.1111/pedi.13079] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 05/03/2020] [Accepted: 06/30/2020] [Indexed: 02/02/2023] Open
Abstract
Neonatal diabetes mellitus (NDM) is a rare form of monogenic diabetes presenting within the first 6 months of life. INS gene promoter mutations have been shown to cause both remitting/relapsing and permanent NDM. We, herein, present three interesting patients with INS gene promoter mutations. Two cousins with an identical homozygous c.-331C > G mutation presented with NDM. The first cousin had nonremitting diabetes and still requires multidose insulin injections at the current age of 6.1 years. However, the other cousin's diabetes remitted at the age of 9 months, and she is still in remission at the age of 3 years with no medication or dietary intervention required (latest HbA1c was 4.9%). The third patient had NDM also due to a homozygous INS promoter c.-331C>A mutation. Her diabetes remitted at the age of 2 months and relapsed at the age of 2.6 years with severe diabetic ketoacidosis (DKA). Distinct clinical phenotype and relapse with severe DKA in one of the three cases suggest that INS promotor mutations can cause a heterogeneous phenotype and even cases exhibiting remission can relapse unpredictably. Therefore, as the age of relapse is unpredictable, close follow-up and family education on diabetes symptoms are essential for cases with remitting/relapsing diabetes due to INS gene mutations.
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Affiliation(s)
- Meliha Demiral
- Gazi Yaşargil Research and Training Hospital, Pediatric Endocrinology, Diyarbakır, Turkey
| | - Huseyin Demirbilek
- Hacettepe University Faculty of Medicine, Department of Pediatric Endocrinology, Ankara, Turkey
| | - Kıymet Çelik
- Gazi Yaşargil Research and Training Hospital, Neonatology, Diyarbakır, Turkey
| | - Nilufer Okur
- Gazi Yaşargil Research and Training Hospital, Neonatology, Diyarbakır, Turkey
| | - Khalid Hussain
- Department of Pediatrics, Division of Endocrinology, Sidra Medicine, Doha, Qatar
| | - Mehmet Nuri Ozbek
- Gazi Yaşargil Research and Training Hospital, Pediatric Endocrinology, Diyarbakır, Turkey
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Glucose-Regulated Protein 94 (GRP94): A Novel Regulator of Insulin-Like Growth Factor Production. Cells 2020; 9:cells9081844. [PMID: 32781621 PMCID: PMC7465916 DOI: 10.3390/cells9081844] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 07/31/2020] [Accepted: 08/04/2020] [Indexed: 01/22/2023] Open
Abstract
Mammals have two insulin-like growth factors (IGF) that are key mediators of somatic growth, tissue differentiation, and cellular responses to stress. Thus, the mechanisms that regulate the bioavailability of IGFs are important in both normal and aberrant development. IGF-I levels are primarily controlled via the growth hormone-IGF axis, in response to nutritional status, and also reflect metabolic diseases and cancer. One mechanism that controls IGF bioavailablity is the binding of circulating IGF to a number of binding proteins that keep IGF in a stable, but receptor non-binding state. However, even before IGF is released from the cells that produce it, it undergoes an obligatory association with a ubiquitous chaperone protein, GRP94. This binding is required for secretion of a properly folded, mature IGF. This chapter reviews the known aspects of the interaction and highlights the specificity issues yet to be determined. The IGF–GRP94 interaction provides a potential novel mechanism of idiopathic short stature, involving the obligatory chaperone and not just IGF gene expression. It also provides a novel target for cancer treatment, as GRP94 activity can be either inhibited or enhanced.
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Tran DT, Pottekat A, Mir SA, Loguercio S, Jang I, Campos AR, Scully KM, Lahmy R, Liu M, Arvan P, Balch WE, Kaufman RJ, Itkin-Ansari P. Unbiased Profiling of the Human Proinsulin Biosynthetic Interaction Network Reveals a Role for Peroxiredoxin 4 in Proinsulin Folding. Diabetes 2020; 69:1723-1734. [PMID: 32457219 PMCID: PMC7372081 DOI: 10.2337/db20-0245] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/15/2020] [Indexed: 12/12/2022]
Abstract
The β-cell protein synthetic machinery is dedicated to the production of mature insulin, which requires the proper folding and trafficking of its precursor, proinsulin. The complete network of proteins that mediate proinsulin folding and advancement through the secretory pathway, however, remains poorly defined. Here we used affinity purification and mass spectrometry to identify, for the first time, the proinsulin biosynthetic interaction network in human islets. Stringent analysis established a central node of proinsulin interactions with endoplasmic reticulum (ER) folding factors, including chaperones and oxidoreductases, that is remarkably conserved in both sexes and across three ethnicities. The ER-localized peroxiredoxin PRDX4 was identified as a prominent proinsulin-interacting protein. In β-cells, gene silencing of PRDX4 rendered proinsulin susceptible to misfolding, particularly in response to oxidative stress, while exogenous PRDX4 improved proinsulin folding. Moreover, proinsulin misfolding induced by oxidative stress or high glucose was accompanied by sulfonylation of PRDX4, a modification known to inactivate peroxiredoxins. Notably, islets from patients with type 2 diabetes (T2D) exhibited significantly higher levels of sulfonylated PRDX4 than islets from healthy individuals. In conclusion, we have generated the first reference map of the human proinsulin interactome to identify critical factors controlling insulin biosynthesis, β-cell function, and T2D.
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Affiliation(s)
- Duc T Tran
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Anita Pottekat
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Saiful A Mir
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | | | - Insook Jang
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | | | - Kathleen M Scully
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Reyhaneh Lahmy
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Ming Liu
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
- Department of Endocrinology and Metabolism, Tianjin Medical University, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - William E Balch
- Department of Molecular Medicine, Scripps Research, La Jolla, CA
- Integrative Structural and Computational Biology, Scripps Research, La Jolla, CA
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Pamela Itkin-Ansari
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
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Sakano D, Inoue A, Enomoto T, Imasaka M, Okada S, Yokota M, Koike M, Araki K, Kume S. Insulin2 Q104del (Kuma) mutant mice develop diabetes with dominant inheritance. Sci Rep 2020; 10:12187. [PMID: 32699230 PMCID: PMC7376009 DOI: 10.1038/s41598-020-68987-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/06/2020] [Indexed: 11/18/2022] Open
Abstract
Insulin gene mutations have been identified to cause monogenic diabetes, and most of which developed permanent neonatal diabetes at young ages before 6 months of age in humans. To establish an animal model of permanent diabetes, we performed genome editing using the CRISPR/Cas9 system. We generated a novel Kuma mutant mice with p.Q104del in the Insulin2 (Ins2) gene in a BRJ background that exhibits a severe immune deficiency. Kuma mutant mice are non-obese and developed hyperglycemia from 3 weeks after birth in both males and females, which are inherited in a dominant mode. Kuma mutant mice displayed reduced insulin protein levels from 3-weeks-old, which seem to be caused by the low stability of the mutant insulin protein. Kuma mutant showed a reduction in islet size and islet mass. Electron microscopic analysis revealed a marked decrease in the number and size of insulin granules in the beta-cells of the mutant mice. Hyperglycemia of the mutant can be rescued by insulin administration. Our results present a novel insulin mutation that causes permanent early-onset diabetes, which provides a model useful for islet transplantation studies.
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Affiliation(s)
- Daisuke Sakano
- School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-25 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Airi Inoue
- School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-25 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Takayuki Enomoto
- School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-25 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan
| | - Mai Imasaka
- Laboratory of Developmental Genetics, Institute of Resource Development and Analysis, Chuo-Ku, Honjo 2-2-1, Kumamoto, 860-0811, Japan.,Department of Genetics, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Seiji Okada
- Division of Hematopoiesis, Joint Research Center for Retroviral Infection, Kumamoto University, Honjo 2-2-1, Kumamoto, 860-0811, Japan
| | - Mutsumi Yokota
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Masato Koike
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Kimi Araki
- Laboratory of Developmental Genetics, Institute of Resource Development and Analysis, Chuo-Ku, Honjo 2-2-1, Kumamoto, 860-0811, Japan.
| | - Shoen Kume
- School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-25 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa, 226-8501, Japan.
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Shariati K, Pappalardo Z, Chopra DG, Yiv N, Sheen R, Ku G. Selective monitoring of insulin secretion after CRISPR interference in intact pancreatic islets despite submaximal infection. Islets 2020; 12:59-69. [PMID: 32579048 PMCID: PMC7527018 DOI: 10.1080/19382014.2020.1752072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Virus-mediated gene knockdown in intact pancreatic islets is technically challenging due to poor infection of the center of the islet. Because the cells that do not have knockdown have normal insulin secretion, measuring changes in insulin secretion after gene knockdown is challenging. We describe a method to monitor insulin secretion from only the beta cells with knockdown of a gene of interest in intact islets using a single lentivirus containing a guide RNA, a luciferase insulin secretion reporter and a dCas9-KRAB cassette. This method allows rapid and inexpensive monitoring of insulin secretion from only those beta cells with knockdown, circumventing the problem of incomplete islet infection.
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Affiliation(s)
| | | | | | | | - Robin Sheen
- Diabetes Center, UCSF, San Francisco, CA, USA
| | - Gregory Ku
- Diabetes Center, UCSF, San Francisco, CA, USA
- Division of Endocrinology and Metabolism, Department of Medicine, UCSF, San Francisco, CA, USA
- CONTACT Gregory Ku 513 Parnassus Ave., San Francisco, CA94143
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38
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Sun J, Xiong Y, Li X, Haataja L, Chen W, Mir SA, Lv L, Madley R, Larkin D, Anjum A, Dhayalan B, Rege N, Wickramasinghe NP, Weiss MA, Itkin-Ansari P, Kaufman RJ, Ostrov DA, Arvan P, Liu M. Role of Proinsulin Self-Association in Mutant INS Gene-Induced Diabetes of Youth. Diabetes 2020; 69:954-964. [PMID: 32139596 PMCID: PMC7171958 DOI: 10.2337/db19-1106] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/22/2020] [Indexed: 02/06/2023]
Abstract
Abnormal interactions between misfolded mutant and wild-type (WT) proinsulin (PI) in the endoplasmic reticulum (ER) drive the molecular pathogenesis of mutant INS gene-induced diabetes of youth (MIDY). How these abnormal interactions are initiated remains unknown. Normally, PI-WT dimerizes in the ER. Here, we suggest that the normal PI-PI contact surface, involving the B-chain, contributes to dominant-negative effects of misfolded MIDY mutants. Specifically, we find that PI B-chain tyrosine-16 (Tyr-B16), which is a key residue in normal PI dimerization, helps confer dominant-negative behavior of MIDY mutant PI-C(A7)Y. Substitutions of Tyr-B16 with either Ala, Asp, or Pro in PI-C(A7)Y decrease the abnormal interactions between the MIDY mutant and PI-WT, rescuing PI-WT export, limiting ER stress, and increasing insulin production in β-cells and human islets. This study reveals the first evidence indicating that noncovalent PI-PI contact initiates dominant-negative behavior of misfolded PI, pointing to a novel therapeutic target to enhance PI-WT export and increase insulin production.
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Affiliation(s)
- Jinhong Sun
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Yi Xiong
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Wei Chen
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
- Beijing Institute of Pharmacology and Toxicology, Beijing, China
| | - Saiful A Mir
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - Li Lv
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Rachel Madley
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Dennis Larkin
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Arfah Anjum
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
| | - Nischay Rege
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH
| | | | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
| | - Pamela Itkin-Ansari
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA
| | - David A Ostrov
- Department of Pathology, Immunology and Laboratory Medicine, University of Florida College of Medicine, Gainesville, FL
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
| | - Ming Liu
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
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Ma W, Chang J, Tong J, Ho U, Yau B, Kebede MA, Thorn P. Arp2/3 nucleates F-actin coating of fusing insulin granules in pancreatic β cells to control insulin secretion. J Cell Sci 2020; 133:jcs236794. [PMID: 32079655 DOI: 10.1242/jcs.236794] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 02/05/2020] [Indexed: 01/11/2023] Open
Abstract
F-actin dynamics are known to control insulin secretion, but the point of intersection with the stimulus-secretion cascade is unknown. Here, using multiphoton imaging of β cells isolated from Lifeact-GFP transgenic mice, we show that glucose stimulation does not cause global changes in subcortical F-actin. Instead, we observe spatially discrete and transient F-actin changes around each fusing granule. This F-actin remodelling is dependent on actin nucleation and is observed for granule fusion induced by either glucose or high potassium stimulation. Using GFP-labelled proteins, we identify local enrichment of Arp3, dynamin 2 and clathrin, all occurring after granule fusion, suggesting early recruitment of an endocytic complex to the fusing granules. Block of Arp2/3 activity with drugs or shRNA inhibits F-actin coating, traps granules at the cell membrane and reduces insulin secretion. Block of formin-mediated actin nucleation also blocks F-actin coating, but has no effect on insulin secretion. We conclude that local Arp2/3-dependent actin nucleation at the sites of granule fusion plays an important role in post-fusion granule dynamics and in the regulation of insulin secretion.
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Affiliation(s)
- Wei Ma
- Discipline of Physiology, School of Medical Sciences, Charles Perkins Centre, University of Sydney, Camperdown 2006, Australia
| | - Jenny Chang
- School of Biomedical Sciences, University of Queensland, St Lucia 4072, Australia
| | - Jason Tong
- Discipline of Physiology, School of Medical Sciences, Charles Perkins Centre, University of Sydney, Camperdown 2006, Australia
| | - Uda Ho
- School of Biomedical Sciences, University of Queensland, St Lucia 4072, Australia
| | - Belinda Yau
- Discipline of Physiology, School of Medical Sciences, Charles Perkins Centre, University of Sydney, Camperdown 2006, Australia
| | - Melkam A Kebede
- Discipline of Physiology, School of Medical Sciences, Charles Perkins Centre, University of Sydney, Camperdown 2006, Australia
| | - Peter Thorn
- Discipline of Physiology, School of Medical Sciences, Charles Perkins Centre, University of Sydney, Camperdown 2006, Australia
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40
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Rege NK, Liu M, Dhayalan B, Chen YS, Smith NA, Rahimi L, Sun J, Guo H, Yang Y, Haataja L, Phillips NFB, Whittaker J, Smith BJ, Arvan P, Ismail-Beigi F, Weiss MA. "Register-shift" insulin analogs uncover constraints of proteotoxicity in protein evolution. J Biol Chem 2020; 295:3080-3098. [PMID: 32005662 DOI: 10.1074/jbc.ra119.011389] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 01/27/2020] [Indexed: 12/16/2022] Open
Abstract
Globular protein sequences encode not only functional structures (the native state) but also protein foldability, i.e. a conformational search that is both efficient and robustly minimizes misfolding. Studies of mutations associated with toxic misfolding have yielded insights into molecular determinants of protein foldability. Of particular interest are residues that are conserved yet dispensable in the native state. Here, we exploited the mutant proinsulin syndrome (a major cause of permanent neonatal-onset diabetes mellitus) to investigate whether toxic misfolding poses an evolutionary constraint. Our experiments focused on an invariant aromatic motif (PheB24-PheB25-TyrB26) with complementary roles in native self-assembly and receptor binding. A novel class of mutations provided evidence that insulin can bind to the insulin receptor (IR) in two different modes, distinguished by a "register shift" in this motif, as visualized by molecular dynamics (MD) simulations. Register-shift variants are active but defective in cellular foldability and exquisitely susceptible to fibrillation in vitro Indeed, expression of the corresponding proinsulin variant induced endoplasmic reticulum stress, a general feature of the mutant proinsulin syndrome. Although not present among vertebrate insulin and insulin-like sequences, a prototypical variant ([GlyB24]insulin) was as potent as WT insulin in a rat model of diabetes. Although in MD simulations the shifted register of receptor engagement is compatible with the structure and allosteric reorganization of the IR-signaling complex, our results suggest that this binding mode is associated with toxic misfolding and so is disallowed in evolution. The implicit threat of proteotoxicity limits sequence variation among vertebrate insulins and insulin-like growth factors.
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Affiliation(s)
- Nischay K Rege
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Ming Liu
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan 48105, Australia; Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, Heping District, 300052 China
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Yen-Shan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Nicholas A Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Leili Rahimi
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106; Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Jinhong Sun
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan 48105, Australia
| | - Huan Guo
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan 48105, Australia
| | - Yanwu Yang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan 48105, Australia
| | - Nelson F B Phillips
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Jonathan Whittaker
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Brian J Smith
- La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical Center, Ann Arbor, Michigan 48105, Australia
| | - Faramarz Ismail-Beigi
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106; Department of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202.
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Zhou Y, Liu Z, Zhang S, Zhuang R, Liu H, Liu X, Qiu X, Zhang M, Zheng Y, Li L, Hong W, Wang T. RILP Restricts Insulin Secretion Through Mediating Lysosomal Degradation of Proinsulin. Diabetes 2020; 69:67-82. [PMID: 31624142 DOI: 10.2337/db19-0086] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 10/06/2019] [Indexed: 11/13/2022]
Abstract
Insulin secretion is tightly regulated by membrane trafficking. RILP (Rab7 interacting lysosomal protein) regulates the endocytic trafficking, but its role in insulin secretion has not been investigated. In this study, we found that overexpression of RILP inhibited insulin secretion in both the β-cell lines and freshly isolated islets. Consequently, the expression of RILP in islets suppressed the ability to recover the glucose homeostasis in type 1 diabetes mice upon transplantation. Of physiological relevance is that RILP expression was upregulated in the diabetic mouse islets. Mechanistically, overexpression of RILP induced insulin granule clustering, decreased the number of proinsulin-containing granules in β-cells, and significantly promoted proinsulin degradation. Conversely, RILP depletion sustained proinsulin and increased insulin secretion. The proinsulin degradation induced by RILP expression was inhibited by lysosomal inhibitors and was Rab7-dependent. Finally, we showed that RILP interacts with insulin granule-associated Rab26 to restrict insulin secretion. This study presents a new pathway regulating insulin secretion and mechanically demonstrates a novel function of RILP in modulating insulin secretion through mediating the lysosomal degradation of proinsulin.
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Affiliation(s)
- Yuxia Zhou
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Zhiyu Liu
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Shengmei Zhang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Ruijuan Zhuang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Huiying Liu
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Xiaoqing Liu
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Xi Qiu
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Ming Zhang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Yanpan Zheng
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Liangcheng Li
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
| | - Wanjin Hong
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
- Institute of Molecular and Cell Biology, A STAR (Agency of Science, Technology and Research), Singapore, Singapore
| | - Tuanlao Wang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Fujian, China
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42
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Morishita Y, Arvan P. Lessons from animal models of endocrine disorders caused by defects of protein folding in the secretory pathway. Mol Cell Endocrinol 2020; 499:110613. [PMID: 31605742 PMCID: PMC6886696 DOI: 10.1016/j.mce.2019.110613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/26/2019] [Accepted: 10/04/2019] [Indexed: 02/06/2023]
Abstract
Most peptide hormones originate from secretory protein precursors synthesized within the endoplasmic reticulum (ER). In this specialized organelle, the newly-made prohormones must fold to their native state. Completion of prohormone folding usually occurs prior to migration through the secretory pathway, as unfolded/misfolded prohormones are retained by mechanisms collectively known as ER quality control. Not only do most monomeric prohormones need to fold properly, but many also dimerize or oligomerize within the ER. If oligomerization occurs before completion of monomer folding then when a poorly folded peptide prohormone is retained by quality control mechanisms, it may confer ER retention upon its oligomerization partners. Conversely, oligomerization between well-folded and improperly folded partners might help to override ER quality control, resulting in rescue of misfolded forms. Both scenarios appear to be possible in different animal models of endocrine disorders caused by genetic defects of protein folding in the secretory pathway. In this paper, we briefly review three such conditions, including familial neurohypophyseal diabetes insipidus, insulin-deficient diabetes mellitus, and hypothyroidism with defective thyroglobulin.
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Affiliation(s)
- Yoshiaki Morishita
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan.
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan School of Medicine, Brehm Tower Room 5112, 1000, Wall St., Ann Arbor, MI, USA.
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43
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Li X, Itani OA, Haataja L, Dumas KJ, Yang J, Cha J, Flibotte S, Shih HJ, Delaney CE, Xu J, Qi L, Arvan P, Liu M, Hu PJ. Requirement for translocon-associated protein (TRAP) α in insulin biogenesis. SCIENCE ADVANCES 2019; 5:eaax0292. [PMID: 31840061 PMCID: PMC6892615 DOI: 10.1126/sciadv.aax0292] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 10/07/2019] [Indexed: 05/26/2023]
Abstract
The mechanistic basis for the biogenesis of peptide hormones and growth factors is poorly understood. Here, we show that the conserved endoplasmic reticulum membrane translocon-associated protein α (TRAPα), also known as signal sequence receptor 1, plays a critical role in the biosynthesis of insulin. Genetic analysis in the nematode Caenorhabditis elegans and biochemical studies in pancreatic β cells reveal that TRAPα deletion impairs preproinsulin translocation while unexpectedly disrupting distal steps in insulin biogenesis including proinsulin processing and secretion. The association of common intronic single-nucleotide variants in the human TRAPα gene with susceptibility to type 2 diabetes and pancreatic β cell dysfunction suggests that impairment of preproinsulin translocation and proinsulin trafficking may contribute to the pathogenesis of type 2 diabetes.
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Affiliation(s)
- Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Omar A. Itani
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Leena Haataja
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Kathleen J. Dumas
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jing Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jeeyeon Cha
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Diabetes, Endocrinology and Metabolism, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Stephane Flibotte
- Departments of Zoology and Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hung-Jen Shih
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Colin E. Delaney
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Jialu Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ling Qi
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Peter Arvan
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Patrick J. Hu
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, USA
- Division of Hematology and Oncology, Vanderbilt University Medical Center, Nashville, TN, USA
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44
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Merriman C, Fu D. Down-regulation of the islet-specific zinc transporter-8 (ZnT8) protects human insulinoma cells against inflammatory stress. J Biol Chem 2019; 294:16992-17006. [PMID: 31591269 DOI: 10.1074/jbc.ra119.010937] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/04/2019] [Indexed: 12/31/2022] Open
Abstract
Zinc transporter-8 (ZnT8) primarily functions as a zinc-sequestrating transporter in the insulin-secretory granules (ISGs) of pancreatic β-cells. Loss-of-function mutations in ZnT8 are associated with protection against type-2 diabetes (T2D), but the protective mechanism is unclear. Here, we developed an in-cell ZnT8 assay to track endogenous ZnT8 responses to metabolic and inflammatory stresses applied to human insulinoma EndoC-βH1 cells. Unexpectedly, high glucose and free fatty acids did not alter cellular ZnT8 levels, but proinflammatory cytokines acutely, reversibly, and gradually down-regulated ZnT8. Approximately 50% of the cellular ZnT8 was localized to the endoplasmic reticulum (ER), which was the primary target of the cytokine-mediated ZnT8 down-regulation. Transcriptome profiling of cytokine-exposed β-cells revealed an adaptive unfolded protein response (UPR) including a marked immunoproteasome activation that coordinately degraded ZnT8 and insulin over a 1,000-fold cytokine concentration range. RNAi-mediated ZnT8 knockdown protected cells against cytokine cytotoxicity, whereas inhibiting immunoproteasomes blocked cytokine-induced ZnT8 degradation and triggered a transition of the adaptive UPR to cell apoptosis. Hence, cytokine-induced down-regulation of the ER ZnT8 level promotes adaptive UPR, acting as a protective mechanism that decongests the ER burden of ZnT8 to protect β-cells from proapoptotic UPR during chronic low-grade inflammation.
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Affiliation(s)
- Chengfeng Merriman
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205
| | - Dax Fu
- Department of Physiology, Johns Hopkins School of Medicine, Baltimore, Maryland 21205
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45
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Al-Khawaga S, Mohammed I, Saraswathi S, Haris B, Hasnah R, Saeed A, Almabrazi H, Syed N, Jithesh P, El Awwa A, Khalifa A, AlKhalaf F, Petrovski G, Abdelalim EM, Hussain K. The clinical and genetic characteristics of permanent neonatal diabetes (PNDM) in the state of Qatar. Mol Genet Genomic Med 2019; 7:e00753. [PMID: 31441606 PMCID: PMC6785445 DOI: 10.1002/mgg3.753] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/04/2019] [Accepted: 04/27/2019] [Indexed: 02/06/2023] Open
Abstract
Background Neonatal diabetes mellitus (NDM) is a rare condition that occurs within the first six months of life. Permanent NDM (PNDM) is caused by mutations in specific genes that are known for their expression at early and/or late stages of pancreatic beta‐ cell development, and are either involved in beta‐cell survival, insulin processing, regulation, and release. The native population in Qatar continues to practice consanguineous marriages that lead to a high level of homozygosity. To our knowledge, there is no previous report on the genomics of NDM among the Qatari population. The aims of the current study are to identify patients with NDM diagnosed between 2001 and 2016, and examine their clinical and genetic characteristics. Methods To calculate the incidence of PNDM, all patients with PNDM diagnosed between 2001 and 2016 were compared to the total number of live births over the 16‐year‐period. Whole Genome Sequencing (WGS) was used to investigate the genetic etiology in the PNDM cohort. Results PNDM was diagnosed in nine (n = 9) patients with an estimated incidence rate of 1:22,938 live births among the indigenous Qatari. Seven different mutations in six genes (PTF1A, GCK, SLC2A2, EIF2AK3, INS, and HNF1B) were identified. In the majority of cases, the genetic etiology was part of a previously identified autosomal recessive disorder. Two novel de novo mutations were identified in INS and HNF1B. Conclusion Qatar has the second highest reported incidence of PNDM worldwide. A majority of PNDM cases present as rare familial autosomal recessive disorders. Pancreas associated transcription factor 1a (PTF1A) enhancer deletions are the most common cause of PNDM in Qatar, with only a few previous cases reported in the literature.
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Affiliation(s)
- Sara Al-Khawaga
- College of Health & Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar.,Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar.,Diabetes Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Idris Mohammed
- College of Health & Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar.,Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Saras Saraswathi
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Basma Haris
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Reem Hasnah
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Amira Saeed
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | | | - Najeeb Syed
- Biomedical Informatics Division, Sidra Medicine, Doha, Qatar
| | - Puthen Jithesh
- Biomedical Informatics Division, Sidra Medicine, Doha, Qatar
| | - Ahmed El Awwa
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar.,Faculty of medicine, Alexandria University, Alexandria, Egypt
| | - Amal Khalifa
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Fawziya AlKhalaf
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Goran Petrovski
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
| | - Essam M Abdelalim
- College of Health & Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar.,Diabetes Research Center, Qatar Biomedical Research Institute, Hamad Bin Khalifa University, Qatar Foundation, Doha, Qatar
| | - Khalid Hussain
- Division of Endocrinology, Department of Pediatric Medicine, Sidra Medicine, Doha, Qatar
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46
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De Leonibus C, Cinque L, Settembre C. Emerging lysosomal pathways for quality control at the endoplasmic reticulum. FEBS Lett 2019; 593:2319-2329. [PMID: 31388984 DOI: 10.1002/1873-3468.13571] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 01/01/2023]
Abstract
Protein misfolding occurring in the endoplasmic reticulum (ER) might eventually lead to aggregation and cellular distress, and is a primary pathogenic mechanism in multiple human disorders. Mammals have developed evolutionary-conserved quality control mechanisms at the level of the ER. The best characterized is the ER-associated degradation (ERAD) pathway, through which misfolded proteins translocate from the ER to the cytosol and are subsequently proteasomally degraded. However, increasing evidence indicates that additional quality control mechanisms apply for misfolded ER clients that are not eligible for ERAD. This review focuses on the alternative, ERAD-independent, mechanisms of clearance of misfolded polypeptides from the ER. These processes, collectively referred to as ER-to-lysosome-associated degradation, involve ER-phagy, microautophagy or vesicular transport. The identification of the underlying molecular mechanisms is particularly important for developing new therapeutic approaches for human diseases associated with protein aggregate formation.
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Affiliation(s)
| | - Laura Cinque
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Carmine Settembre
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy.,Department of Medical and Translational Science, University of Naples "Federico II", Italy
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Zhu R, Li X, Xu J, Barrabi C, Kekulandara D, Woods J, Chen X, Liu M. Defective endoplasmic reticulum export causes proinsulin misfolding in pancreatic β cells. Mol Cell Endocrinol 2019; 493:110470. [PMID: 31158417 PMCID: PMC6613978 DOI: 10.1016/j.mce.2019.110470] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/30/2019] [Accepted: 05/30/2019] [Indexed: 02/06/2023]
Abstract
Endoplasmic reticulum (ER) homeostasis is essential for cell function. Increasing evidence indicates that, efficient protein ER export is important for ER homeostasis. However, the consequence of impaired ER export remains largely unknown. Herein, we found that defective ER protein transport caused by either Sar1 mutants or brefeldin A impaired proinsulin oxidative folding in the ER of β-cells. Misfolded proinsulin formed aberrant disulfide-linked dimers and high molecular weight proinsulin complexes, and induced ER stress. Limiting proinsulin load to the ER alleviated ER stress, indicating that misfolded proinsulin is a direct cause of ER stress. This study revealed significance of efficient ER export in maintaining ER protein homeostasis and native folding of proinsulin. Given the fact that proinsulin misfolding plays an important role in diabetes, this study suggests that enhancing ER export may be a potential therapeutic target to prevent/delay β-cell failure caused by proinsulin misfolding and ER stress.
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Affiliation(s)
- Ruimin Zhu
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA; Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Jialu Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China
| | - Cesar Barrabi
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Dilini Kekulandara
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - James Woods
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Xuequn Chen
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, USA.
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin 300052, China.
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Liu S, Li X, Yang J, Zhu R, Fan Z, Xu X, Feng W, Cui J, Sun J, Liu M. Misfolded proinsulin impairs processing of precursor of insulin receptor and insulin signaling in β cells. FASEB J 2019; 33:11338-11348. [PMID: 31311313 PMCID: PMC6766638 DOI: 10.1096/fj.201900442r] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Insulin resistance in classic insulin-responsive tissues is a hallmark of type 2 diabetes (T2D). However, the pathologic significance of β-cell insulin resistance and the underlying mechanisms contributing to defective insulin signaling in β cells remain largely unknown. Emerging evidence indicates that proinsulin misfolding is not only the molecular basis of mutant INS-gene–induced diabetes of youth (MIDY) but also an important contributor in the development and progression of T2D. However, the molecular basis of β-cell failure caused by misfolded proinsulin is still incompletely understood. Herein, using Akita mice expressing diabetes-causing mutant proinsulin, we found that misfolded proinsulin abnormally interacted with the precursor of insulin receptor (ProIR) in the endoplasmic reticulum (ER), impaired ProIR maturation to insulin receptor (IR), and decreased insulin signaling in β cells. Importantly, using db/db insulin-resistant mice, we found that oversynthesis of proinsulin led to an increased proinsulin misfolding, which resulted in impairments of ProIR processing and insulin signaling in β cells. These results reveal for the first time that misfolded proinsulin can interact with ProIR in the ER, impairing intracellular processing of ProIR and leading to defective insulin signaling that may contribute to β-cell failure in both MIDY and T2D.—Liu, S., Li, X., Yang, J., Zhu, R., Fan, Z., Xu, X., Feng, W., Cui, J., Sun, J., Liu, M. Misfolded proinsulin impairs processing of precursor of insulin receptor and insulin signaling in β cells.
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Affiliation(s)
- Shiqun Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jing Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Ruimin Zhu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Zhenqian Fan
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Wenli Feng
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingqiu Cui
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinhong Sun
- Department of Health Management, Tianjin Medical University General Hospital, Tianjin, China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
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Arunagiri A, Haataja L, Pottekat A, Pamenan F, Kim S, Zeltser LM, Paton AW, Paton JC, Tsai B, Itkin-Ansari P, Kaufman RJ, Liu M, Arvan P. Proinsulin misfolding is an early event in the progression to type 2 diabetes. eLife 2019; 8:44532. [PMID: 31184302 PMCID: PMC6559786 DOI: 10.7554/elife.44532] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/09/2019] [Indexed: 02/06/2023] Open
Abstract
Biosynthesis of insulin – critical to metabolic homeostasis – begins with folding of the proinsulin precursor, including formation of three evolutionarily conserved intramolecular disulfide bonds. Remarkably, normal pancreatic islets contain a subset of proinsulin molecules bearing at least one free cysteine thiol. In human (or rodent) islets with a perturbed endoplasmic reticulum folding environment, non-native proinsulin enters intermolecular disulfide-linked complexes. In genetically obese mice with otherwise wild-type islets, disulfide-linked complexes of proinsulin are more abundant, and leptin receptor-deficient mice, the further increase of such complexes tracks with the onset of islet insulin deficiency and diabetes. Proinsulin-Cys(B19) and Cys(A20) are necessary and sufficient for the formation of proinsulin disulfide-linked complexes; indeed, proinsulin Cys(B19)-Cys(B19) covalent homodimers resist reductive dissociation, highlighting a structural basis for aberrant proinsulin complex formation. We conclude that increased proinsulin misfolding via disulfide-linked complexes is an early event associated with prediabetes that worsens with ß-cell dysfunction in type two diabetes. Our body fine-tunes the amount of sugar in our blood thanks to specialized ‘beta cells’ in the pancreas, which can release a hormone called insulin. To produce insulin, the beta cells first need to build an early version of the molecule – known as proinsulin – inside a cellular compartment called the endoplasmic reticulum. This process involves the formation of internal staples that keep the molecule of proinsulin folded correctly. Individuals developing type 2 diabetes have spikes of sugar in their blood, and so their bodies often respond by trying to make large amounts of insulin. After a while, the beta cells can fail to keep up, which brings on the full-blown disease. However, scientists have discovered that early in type 2 diabetes, the endoplasmic reticulum of beta cells can already show signs of stress; yet, the exact causes of this early damage are still unknown. To investigate this, Arunagiri et al. looked into whether proinsulin folds correctly during the earliest stages of type 2 diabetes. Biochemical experiments showed that even healthy beta cells contained some misfolded proinsulin molecules, where the molecular staples that should fold proinsulin internally were instead abnormally linking proinsulin molecules together. Further work revealed that the misfolded proinsulin was accumulating inside the endoplasmic reticulum. Finally, obese mice that were in the earliest stages of type 2 diabetes had the highest levels of abnormal proinsulin in their beta cells. Overall, the work by Arunagiri et al. suggests that large amounts of proinsulin molecules stapling themselves to each other in the endoplasmic reticulum of beta cells could be an early hallmark of the disease, and could make it get worse. A separate study by Jang et al. also shows that a protein that limits the misfolding of proinsulin is key to maintain successful insulin production in animals eating a Western-style, high fat diet. Hundreds of millions of people around the world have type 2 diabetes, and this number is rising quickly. Detecting and then fixing early problems associated with the condition may help to stop the disease in its track.
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Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
| | - Anita Pottekat
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States
| | - Fawnnie Pamenan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
| | - Soohyun Kim
- Department of Biomedical Science and Technology, Konkuk University, Gwangjin-gu, Republic of Korea
| | - Lori M Zeltser
- Department of Pathology and Cell Biology, Naomi Berrie Diabetes Center, Columbia University, New York, United States
| | - Adrienne W Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - James C Paton
- Research Centre for Infectious Diseases, Department of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, United States
| | - Pamela Itkin-Ansari
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States
| | - Randal J Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, United States
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States.,Department of Endocrinology and Metabolism, Tianjin Medical University, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor, United States
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Cunningham CN, Williams JM, Knupp J, Arunagiri A, Arvan P, Tsai B. Cells Deploy a Two-Pronged Strategy to Rectify Misfolded Proinsulin Aggregates. Mol Cell 2019; 75:442-456.e4. [PMID: 31176671 DOI: 10.1016/j.molcel.2019.05.011] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 04/17/2019] [Accepted: 05/08/2019] [Indexed: 02/06/2023]
Abstract
Insulin gene coding sequence mutations are known to cause mutant INS-gene-induced diabetes of youth (MIDY), yet the cellular pathways needed to prevent misfolded proinsulin accumulation remain incompletely understood. Here, we report that Akita mutant proinsulin forms detergent-insoluble aggregates that entrap wild-type (WT) proinsulin in the endoplasmic reticulum (ER), thereby blocking insulin production. Two distinct quality-control mechanisms operate together to combat this insult: the ER luminal chaperone Grp170 prevents proinsulin aggregation, while the ER membrane morphogenic protein reticulon-3 (RTN3) disposes of aggregates via ER-coupled autophagy (ER-phagy). We show that enhanced RTN-dependent clearance of aggregated Akita proinsulin helps to restore ER export of WT proinsulin, which can promote WT insulin production, potentially alleviating MIDY. We also find that RTN3 participates in the clearance of other mutant prohormone aggregates. Together, these results identify a series of substrates of RTN3-mediated ER-phagy, highlighting RTN3 in the disposal of pathogenic prohormone aggregates.
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Affiliation(s)
- Corey N Cunningham
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Jeffrey M Williams
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA
| | - Jeffrey Knupp
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Anoop Arunagiri
- Division of Metabolism Endocrinology & Diabetes, Comprehensive Diabetes Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Peter Arvan
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Division of Metabolism Endocrinology & Diabetes, Comprehensive Diabetes Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
| | - Billy Tsai
- Department of Cell & Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, BSRB 3043, Ann Arbor, MI 48109, USA; Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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