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Freese J, Al-Rawi R, Choat H, Martin A, Lunsford A, Tse H, Mick G, McCormick K. Proinsulin to C-Peptide Ratio in the First Year After Diagnosis of Type 1 Diabetes. J Clin Endocrinol Metab 2021; 106:e4318-e4326. [PMID: 34228132 DOI: 10.1210/clinem/dgab463] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Indexed: 11/19/2022]
Abstract
OBJECTIVE The proinsulin to C-peptide (PI:C) ratio is reputedly a biomarker of β-cell endoplasmic reticulum (ER) stress. OBJECTIVE This study examined the natural history of the PI:C ratio and its correlation with residual β-cell function in childhood new-onset type 1 diabetes (T1D). Over the first year of T1D, the temporal trend in fasting and nutrient-stimulated PI data is limited. METHODS PI was a secondary pre-planned analysis of our 1-year, randomized, double-blind, placebo-controlled gamma aminobutyric acid (GABA) trial in new-onset T1D. Of the 99 participants in the primary study, aged 4 to 18 years, 30 were placebo. This study only involved the 30 placebo patients; all were enrolled within 5 weeks of T1D diagnosis. A liquid mixed meal tolerance test was administered at baseline and 5 and 12 months for determination of C-peptide, PI, glucose, and hemoglobin A1C. RESULTS Both the fasting (P = 0.0003) and stimulated (P = 0.00008) PI:C ratios increased from baseline to 12 months, indicating escalating β-cell ER stress. The baseline fasting PI correlated with the fasting change in C-peptide at 12 months (P = 0.004) with a higher PI correlating with greater decline in C-peptide. Patients with an insulin-adjusted A1C >9% (hence, not in remission) had higher fasting PI:C ratios. Younger age at diagnosis correlated with a higher PI:C ratio (P = 0.04). CONCLUSION Children with new-onset T1D undergo progressive β-cell ER stress and aberrant proinsulin processing, as evidenced by increasing PI:C ratios. Moreover, the PI:C ratio reflects more aggressive β-cell onslaught with younger age, as well as diminished glycemic control.
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Affiliation(s)
- Jurhee Freese
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Rawan Al-Rawi
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Heather Choat
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Alexandra Martin
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Alison Lunsford
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Hubert Tse
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Gail Mick
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Kenneth McCormick
- Department of Pediatrics, Division of Pediatric Endocrinology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
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A point mutation in the Pdia6 gene results in loss of pancreatic β-cell identity causing overt diabetes. Mol Metab 2021; 54:101334. [PMID: 34487921 PMCID: PMC8515296 DOI: 10.1016/j.molmet.2021.101334] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/06/2021] [Accepted: 08/31/2021] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Protein disulfide isomerases (PDIs) are oxidoreductases that are involved in catalyzing the formation and rearrangement of disulfide bonds during protein folding. One of the PDI members is the PDI-associated 6 (PDIA6) protein, which has been shown to play a vital role in β-cell dysfunction and diabetes. However, very little is known about the function of this protein in β-cells in vivo. This study aimed to describe the consequences of a point mutation in Pdia6 on β-cell development and function. METHODS We generated an ENU mouse model carrying a missense mutation (Phe175Ser) in the second thioredoxin domain of the Pdia6 gene. Using biochemical and molecular tools, we determined the effects of the mutation on the β-cell development at embryonic day (E)18.5 and β-cell identity as well as function at postnatal stages. RESULTS Mice homozygous for the Phe175Ser (F175S) mutation were mildly hyperglycemic at weaning and subsequently became hypoinsulinemic and overtly diabetic at the adult stage. Although no developmental phenotype was detected during embryogenesis, mutant mice displayed reduced insulin-expressing β-cells at P14 and P21 without any changes in the rate of cell death and proliferation. Further analysis revealed an increase in BiP and the PDI family member PDIA4, but without any concomitant apoptosis and cell death. Instead, the expression of prominent markers of β-cell maturation and function, such as Ins2, Mafa, and Slc2a2, along with increased expression of α-cell markers, Mafb, and glucagon was observed in adult mice, suggesting loss of β-cell identity. CONCLUSIONS The results demonstrate that a global Pdia6 mutation renders mice hypoinsulinemic and hyperglycemic. This occurs due to the loss of pancreatic β-cell function and identity, suggesting a critical role of PDIA6 specifically for β-cells.
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Azarova I, Klyosova E, Polonikov A. The Link between Type 2 Diabetes Mellitus and the Polymorphisms of Glutathione-Metabolizing Genes Suggests a New Hypothesis Explaining Disease Initiation and Progression. Life (Basel) 2021; 11:life11090886. [PMID: 34575035 PMCID: PMC8466482 DOI: 10.3390/life11090886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 08/25/2021] [Accepted: 08/27/2021] [Indexed: 01/11/2023] Open
Abstract
The present study investigated whether type 2 diabetes (T2D) is associated with polymorphisms of genes encoding glutathione-metabolizing enzymes such as glutathione synthetase (GSS) and gamma-glutamyl transferase 7 (GGT7). A total of 3198 unrelated Russian subjects including 1572 T2D patients and 1626 healthy subjects were enrolled. Single nucleotide polymorphisms (SNPs) of the GSS and GGT7 genes were genotyped using the MassArray-4 system. We found that the GSS and GGT7 gene polymorphisms alone and in combinations are associated with T2D risk regardless of sex, age, and body mass index, as well as correlated with plasma glutathione, hydrogen peroxide, and fasting blood glucose levels. Polymorphisms of GSS (rs13041792) and GGT7 (rs6119534 and rs11546155) genes were associated with the tissue-specific expression of genes involved in unfolded protein response and the regulation of proteostasis. Transcriptome-wide association analysis has shown that the pancreatic expression of some of these genes such as EDEM2, MYH7B, MAP1LC3A, and CPNE1 is linked to the genetic risk of T2D. A comprehensive analysis of the data allowed proposing a new hypothesis for the etiology of type 2 diabetes that endogenous glutathione deficiency might be a key condition responsible for the impaired folding of proinsulin which triggered an unfolded protein response, ultimately leading to beta-cell apoptosis and disease development.
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Affiliation(s)
- Iuliia Azarova
- Department of Biological Chemistry, Kursk State Medical University, 3 Karl Marx Street, 305041 Kursk, Russia;
- Laboratory of Biochemical Genetics and Metabolomics, Research Institute for Genetic and Molecular Epidemiology, Kursk State Medical University, 18 Yamskaya St., 305041 Kursk, Russia;
| | - Elena Klyosova
- Laboratory of Biochemical Genetics and Metabolomics, Research Institute for Genetic and Molecular Epidemiology, Kursk State Medical University, 18 Yamskaya St., 305041 Kursk, Russia;
| | - Alexey Polonikov
- Laboratory of Statistical Genetics and Bioinformatics, Research Institute for Genetic and Molecular Epidemiology, Kursk State Medical University, 18 Yamskaya St., 305041 Kursk, Russia
- Department of Biology, Medical Genetics and Ecology, Kursk State Medical University, 3 Karl Marx Street, 305041 Kursk, Russia
- Correspondence: ; Tel.: +7-471-258-8147
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Chen YS, Gleaton J, Yang Y, Dhayalan B, Phillips NB, Liu Y, Broadwater L, Jarosinski MA, Chatterjee D, Lawrence MC, Hattier T, Michael MD, Weiss MA. Insertion of a synthetic switch into insulin provides metabolite-dependent regulation of hormone-receptor activation. Proc Natl Acad Sci U S A 2021; 118:e2103518118. [PMID: 34290145 PMCID: PMC8325334 DOI: 10.1073/pnas.2103518118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Insulin-signaling requires conformational change: whereas the free hormone and its receptor each adopt autoinhibited conformations, their binding leads to structural reorganization. To test the functional coupling between insulin's "hinge opening" and receptor activation, we inserted an artificial ligand-dependent switch into the insulin molecule. Ligand-binding disrupts an internal tether designed to stabilize the hormone's native closed and inactive conformation, thereby enabling productive receptor engagement. This scheme exploited a diol sensor (meta-fluoro-phenylboronic acid at GlyA1) and internal diol (3,4-dihydroxybenzoate at LysB28). The sensor recognizes monosaccharides (fructose > glucose). Studies of insulin-signaling in human hepatoma-derived cells (HepG2) demonstrated fructose-dependent receptor autophosphorylation leading to appropriate downstream signaling events, including a specific kinase cascade and metabolic gene regulation (gluconeogenesis and lipogenesis). Addition of glucose (an isomeric ligand with negligible sensor affinity) did not activate the hormone. Similarly, metabolite-regulated signaling was not observed in control studies of 1) an unmodified insulin analog or 2) an analog containing a diol sensor without internal tethering. Although secondary structure (as probed by circular dichroism) was unaffected by ligand-binding, heteronuclear NMR studies revealed subtle local and nonlocal monosaccharide-dependent changes in structure. Insertion of a synthetic switch into insulin has thus demonstrated coupling between hinge-opening and allosteric holoreceptor signaling. In addition to this foundational finding, our results provide proof of principle for design of a mechanism-based metabolite-responsive insulin. In particular, replacement of the present fructose sensor by an analogous glucose sensor may enable translational development of a "smart" insulin analog to mitigate hypoglycemic risk in diabetes therapy.
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Affiliation(s)
- Yen-Shan Chen
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | | | - Yanwu Yang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Balamurugan Dhayalan
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Nelson B Phillips
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
| | - Yule Liu
- Thermalin Inc., Cleveland, OH 44106
| | | | - Mark A Jarosinski
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Deepak Chatterjee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Michael C Lawrence
- Structural Biology Division, WEHI, Parkville, VIC 3052, Australia
- Department of Medical Biology, University of Melbourne, Royal Parade, Parkville, VIC 3050, Australia
| | | | | | - Michael A Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202;
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Mustapha S, Mohammed M, Azemi AK, Jatau AI, Shehu A, Mustapha L, Aliyu IM, Danraka RN, Amin A, Bala AA, Ahmad WANW, Rasool AHG, Mustafa MR, Mokhtar SS. Current Status of Endoplasmic Reticulum Stress in Type II Diabetes. Molecules 2021; 26:4362. [PMID: 34299638 PMCID: PMC8307902 DOI: 10.3390/molecules26144362] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/10/2021] [Accepted: 07/17/2021] [Indexed: 12/12/2022] Open
Abstract
The endoplasmic reticulum (ER) plays a multifunctional role in lipid biosynthesis, calcium storage, protein folding, and processing. Thus, maintaining ER homeostasis is essential for cellular functions. Several pathophysiological conditions and pharmacological agents are known to disrupt ER homeostasis, thereby, causing ER stress. The cells react to ER stress by initiating an adaptive signaling process called the unfolded protein response (UPR). However, the ER initiates death signaling pathways when ER stress persists. ER stress is linked to several diseases, such as cancer, obesity, and diabetes. Thus, its regulation can provide possible therapeutic targets for these. Current evidence suggests that chronic hyperglycemia and hyperlipidemia linked to type II diabetes disrupt ER homeostasis, thereby, resulting in irreversible UPR activation and cell death. Despite progress in understanding the pathophysiology of the UPR and ER stress, to date, the mechanisms of ER stress in relation to type II diabetes remain unclear. This review provides up-to-date information regarding the UPR, ER stress mechanisms, insulin dysfunction, oxidative stress, and the therapeutic potential of targeting specific ER stress pathways.
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Affiliation(s)
- Sagir Mustapha
- Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu 16150, Kelantan, Malaysia
- Department of Pharmacology and Therapeutics, Ahmadu Bello University, Zaria 810107, Kaduna, Nigeria
| | - Mustapha Mohammed
- School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang 11800, Pulau Pinang, Malaysia
- Department of Clinical Pharmacy and Pharmacy Practice, Ahmadu Bello University, Zaria 810107, Kaduna, Nigeria
| | - Ahmad Khusairi Azemi
- Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu 16150, Kelantan, Malaysia
| | - Abubakar Ibrahim Jatau
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, TAS 7005, Australia
| | - Aishatu Shehu
- Department of Pharmacology and Therapeutics, Ahmadu Bello University, Zaria 810107, Kaduna, Nigeria
| | - Lukman Mustapha
- Department of Pharmaceutical and Medicinal Chemistry, Kaduna State University, Kaduna 800241, Kaduna, Nigeria
| | - Ibrahim Muazzamu Aliyu
- Department of Pharmacology and Therapeutics, Ahmadu Bello University, Zaria 810107, Kaduna, Nigeria
| | - Rabi'u Nuhu Danraka
- Department of Pharmacology and Therapeutics, Ahmadu Bello University, Zaria 810107, Kaduna, Nigeria
| | - Abdulbasit Amin
- Department of Physiology, Faculty of Basic Medical Sciences, University of Ilorin, Ilorin 240103, Kwara, Nigeria
- Membrane Traffic Group, Instituto Gulbenkian de Ciencia, 2784-156 Lisbon, Portugal
| | - Auwal Adam Bala
- Department of Pharmacology, College of Medicine and Health Sciences, Federal University Dutse, Dutse 720281, Jigawa, Nigeria
- Department of Pharmacology and Therapeutics, Faculty of Pharmaceutical Sciences, Bayero University Kano, Kano 700241, Kano, Nigeria
| | - Wan Amir Nizam Wan Ahmad
- Biomedicine Programme, School of Health Sciences, Universiti Sains Malaysia, Kota Bharu 16150, Kelantan, Malaysia
| | - Aida Hanum Ghulam Rasool
- Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu 16150, Kelantan, Malaysia
| | - Mohd Rais Mustafa
- Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur 50603, Malaysia
| | - Siti Safiah Mokhtar
- Department of Pharmacology, School of Medical Sciences, Universiti Sains Malaysia, Kota Bharu 16150, Kelantan, Malaysia
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Ramzy A, Kieffer TJ. Altered islet prohormone processing: A cause or consequence of diabetes? Physiol Rev 2021; 102:155-208. [PMID: 34280055 DOI: 10.1152/physrev.00008.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peptide hormones are first produced as larger precursor prohormones that require endoproteolytic cleavage to liberate the mature hormones. A structurally conserved but functionally distinct family of nine prohormone convertase enzymes (PCs) are responsible for cleavage of protein precursors of which PC1/3 and PC2 are known to be exclusive to neuroendocrine cells and responsible for prohormone cleavage. Differential expression of PCs within tissues define prohormone processing; whereas glucagon is the major product liberated from proglucagon via PC2 in pancreatic α-cells, proglucagon is preferentially processed by PC1/3 in intestinal L cells to produce glucagon-like peptides 1 and 2 (GLP-1, GLP-2). Beyond our understanding of processing of islet prohormones in healthy islets, there is convincing evidence that proinsulin, proIAPP, and proglucagon processing is altered during prediabetes and diabetes. There is predictive value of elevated circulating proinsulin or proinsulin : C-peptide ratio for progression to type 2 diabetes and elevated proinsulin or proinsulin : C-peptide is predictive for development of type 1 diabetes in at risk groups. After onset of diabetes, patients have elevated circulating proinsulin and proIAPP and proinsulin may be an autoantigen in type 1 diabetes. Further, preclinical studies reveal that α-cells have altered proglucagon processing during diabetes leading to increased GLP-1 production. We conclude that despite strong associative data, current evidence is inconclusive on the potential causal role of impaired prohormone processing in diabetes, and suggest that future work should focus on resolving the question of whether altered prohormone processing is a causal driver or merely a consequence of diabetes pathology.
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Affiliation(s)
- Adam Ramzy
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Timothy J Kieffer
- Laboratory of Molecular and Cellular Medicine, Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada.,Department of Surgery, University of British Columbia, Vancouver, BC, Canada.,School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada
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Li Y, Sun F, Yue TT, Wang FX, Yang CL, Luo JH, Rong SJ, Xiong F, Zhang S, Wang CY. Revisiting the Antigen-Presenting Function of β Cells in T1D Pathogenesis. Front Immunol 2021; 12:690783. [PMID: 34335595 PMCID: PMC8318689 DOI: 10.3389/fimmu.2021.690783] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 06/30/2021] [Indexed: 12/17/2022] Open
Abstract
Type 1 diabetes (T1D) is characterized by the unresolved autoimmune inflammation and islet β cell destruction. The islet resident antigen-presenting cells (APCs) including dendritic cells and macrophages uptake and process the β cell-derived antigens to prime the autoreactive diabetogenic T cells. Upon activation, those autoreactive T cells produce copious amount of IFN-γ, TNF-α and IL-1β to induce β cell stress and death. Autoimmune attack and β cell damage intertwine together to push forward this self-destructive program, leading to T1D onset. However, β cells are far beyond a passive participant during the course of T1D development. Herein in this review, we summarized how β cells are actively involved in the initiation of autoimmune responses in T1D setting. Specifically, β cells produce modified neoantigens under stressed condition, which is coupled with upregulated expression of MHC I/II and co-stimulatory molecules as well as other immune modules, that are essential properties normally exhibited by the professional APCs. At the cellular level, this subset of APC-like β cells dynamically interacts with plasmacytoid dendritic cells (pDCs) and manifests potency to activate autoreactive CD4 and CD8 T cells, by which β cells initiate early autoimmune responses predisposing to T1D development. Overall, the antigen-presenting function of β cells helps to explain the tissue specificity of T1D and highlights the active roles of structural cells played in the pathogenesis of various immune related disorders.
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Affiliation(s)
- Yang Li
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Sun
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tian-Tian Yue
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fa-Xi Wang
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chun-Liang Yang
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jia-Hui Luo
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shan-Jie Rong
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Xiong
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shu Zhang
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Cong-Yi Wang
- The Center for Biomedical Research, Department of Respiratory and Critical Care Medicine, NHC Key Laboratory of Pulmonary Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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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: 14] [Impact Index Per Article: 4.7] [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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Saadati M, Jamali Y. The effects of beta-cell mass and function, intercellular coupling, and islet synchrony on [Formula: see text] dynamics. Sci Rep 2021; 11:10268. [PMID: 33986325 PMCID: PMC8119479 DOI: 10.1038/s41598-021-89333-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 04/26/2021] [Indexed: 11/30/2022] Open
Abstract
Type 2 diabetes (T2D) is a challenging metabolic disorder characterized by a substantial loss of [Formula: see text]-cell mass and alteration of [Formula: see text]-cell function in the islets of Langerhans, disrupting insulin secretion and glucose homeostasis. The mechanisms for deficiency in [Formula: see text]-cell mass and function during the hyperglycemia development and T2D pathogenesis are complex. To study the relative contribution of [Formula: see text]-cell mass to [Formula: see text]-cell function in T2D, we make use of a comprehensive electrophysiological model of human [Formula: see text]-cell clusters. We find that defect in [Formula: see text]-cell mass causes a functional decline in single [Formula: see text]-cell, impairment in intra-islet synchrony, and changes in the form of oscillatory patterns of membrane potential and intracellular [Formula: see text] concentration, which can lead to changes in insulin secretion dynamics and in insulin levels. The model demonstrates a good correspondence between suppression of synchronizing electrical activity and published experimental measurements. We then compare the role of gap junction-mediated electrical coupling with both [Formula: see text]-cell synchronization and metabolic coupling in the behavior of [Formula: see text] concentration dynamics within human islets. Our results indicate that inter-[Formula: see text]-cellular electrical coupling depicts a more important factor in shaping the physiological regulation of islet function and in human T2D. We further predict that varying the whole-cell conductance of delayed rectifier [Formula: see text] channels modifies oscillatory activity patterns of [Formula: see text]-cell population lacking intercellular coupling, which significantly affect [Formula: see text] concentration and insulin secretion.
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Affiliation(s)
- Maryam Saadati
- Biomathematics Laboratory, Department of Applied Mathematics, School of Mathematical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Yousef Jamali
- Biomathematics Laboratory, Department of Applied Mathematics, School of Mathematical Sciences, Tarbiat Modares University, Tehran, Iran
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60
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Isolation and Proteomics of the Insulin Secretory Granule. Metabolites 2021; 11:metabo11050288. [PMID: 33946444 PMCID: PMC8147143 DOI: 10.3390/metabo11050288] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 04/28/2021] [Accepted: 04/28/2021] [Indexed: 12/21/2022] Open
Abstract
Insulin, a vital hormone for glucose homeostasis is produced by pancreatic beta-cells and when secreted, stimulates the uptake and storage of glucose from the blood. In the pancreas, insulin is stored in vesicles termed insulin secretory granules (ISGs). In Type 2 diabetes (T2D), defects in insulin action results in peripheral insulin resistance and beta-cell compensation, ultimately leading to dysfunctional ISG production and secretion. ISGs are functionally dynamic and many proteins present either on the membrane or in the lumen of the ISG may modulate and affect different stages of ISG trafficking and secretion. Previously, studies have identified few ISG proteins and more recently, proteomics analyses of purified ISGs have uncovered potential novel ISG proteins. This review summarizes the proteins identified in the current ISG proteomes from rat insulinoma INS-1 and INS-1E cell lines. Here, we also discuss techniques of ISG isolation and purification, its challenges and potential future directions.
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Carré A, Mallone R. Making Insulin and Staying Out of Autoimmune Trouble: The Beta-Cell Conundrum. Front Immunol 2021; 12:639682. [PMID: 33854508 PMCID: PMC8039383 DOI: 10.3389/fimmu.2021.639682] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/12/2021] [Indexed: 12/28/2022] Open
Abstract
Autoimmune type 1 diabetes (T1D) results from the intricate crosstalk of various immune cell types. CD8+ T cells dominate the pro-inflammatory milieu of islet infiltration (insulitis), and are considered as key effectors of beta-cell destruction, through the recognition of MHC Class I-peptide complexes. The pathways generating MHC Class I-restricted antigens in beta cells are poorly documented. Given their specialized insulin secretory function, the associated granule processing and degradation pathways, basal endoplasmic reticulum stress and susceptibility to additional stressors, alternative antigen processing and presentation (APP) pathways are likely to play a significant role in the generation of the beta-cell immunopeptidome. As direct evidence is missing, we here intersect the specificities of beta-cell function and the literature about APP in other cellular models to generate some hypotheses on APPs relevant to beta cells. We further elaborate on the potential role of these pathways in T1D pathogenesis, based on the current knowledge of antigens presented by beta cells. A better understanding of these pathways may pinpoint novel mechanisms amenable to therapeutic targeting to modulate the immunogenicity of beta cells.
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Affiliation(s)
- Alexia Carré
- Université de Paris, Institut Cochin, CNRS, INSERM, Paris, France
| | - Roberto Mallone
- Université de Paris, Institut Cochin, CNRS, INSERM, Paris, France.,Assistance Publique Hôpitaux de Paris, Service de Diabétologie et Immunologie Clinique, Cochin Hospital, Paris, France
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Fernandes-da-Silva A, Miranda CS, Santana-Oliveira DA, Oliveira-Cordeiro B, Rangel-Azevedo C, Silva-Veiga FM, Martins FF, Souza-Mello V. Endoplasmic reticulum stress as the basis of obesity and metabolic diseases: focus on adipose tissue, liver, and pancreas. Eur J Nutr 2021; 60:2949-2960. [PMID: 33742254 DOI: 10.1007/s00394-021-02542-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Accepted: 03/11/2021] [Indexed: 12/11/2022]
Abstract
Obesity challenges lipid and carbohydrate metabolism. The resulting glucolipotoxicity causes endoplasmic reticulum (ER) dysfunction, provoking the accumulation of immature proteins, which triggers the unfolded protein reaction (UPR) as an attempt to reestablish ER homeostasis. When the three branches of UPR fail to correct the unfolded/misfolded proteins, ER stress happens. Excessive dietary saturated fatty acids or fructose exhibit the same impact on the ER stress, induced by excessive ectopic fat accumulation or rising blood glucose levels, and meta-inflammation. These metabolic abnormalities can alleviate through dietary interventions. Many pathways are disrupted in adipose tissue, liver, and pancreas during ER stress, compromising browning and thermogenesis, favoring hepatic lipogenesis, and impairing glucose-stimulated insulin secretion within pancreatic beta cells. As a result, ER stress takes part in obesity, hepatic steatosis, and diabetes pathogenesis, arising as a potential target to treat or even prevent metabolic diseases. The scientific community seeks strategies to alleviate ER stress by avoiding inflammation, apoptosis, lipogenesis suppression, and insulin sensitivity augmentation through pharmacological and non-pharmacological interventions. This comprehensive review aimed to describe the contribution of excessive dietary fat or sugar to ER stress and the impact of this adverse cellular environment on adipose tissue, liver, and pancreas function.
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Affiliation(s)
- Aline Fernandes-da-Silva
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Carolline Santos Miranda
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Daiana Araujo Santana-Oliveira
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Brenda Oliveira-Cordeiro
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Camilla Rangel-Azevedo
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Flávia Maria Silva-Veiga
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Fabiane Ferreira Martins
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil
| | - Vanessa Souza-Mello
- Laboratory of Morphometry, Metabolism, and Cardiovascular Diseases, Biomedical Center, Institute of Biology, State University of Rio de Janeiro, Av 28 de Setembro 87 fds, Rio de Janeiro, RJ, 20551-030, Brazil.
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Eguchi N, Vaziri ND, Dafoe DC, Ichii H. The Role of Oxidative Stress in Pancreatic β Cell Dysfunction in Diabetes. Int J Mol Sci 2021; 22:ijms22041509. [PMID: 33546200 PMCID: PMC7913369 DOI: 10.3390/ijms22041509] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/29/2021] [Accepted: 01/30/2021] [Indexed: 02/07/2023] Open
Abstract
Diabetes is a chronic metabolic disorder characterized by inappropriately elevated glucose levels as a result of impaired pancreatic β cell function and insulin resistance. Extensive studies have been conducted to elucidate the mechanism involved in the development of β cell failure and death under diabetic conditions such as hyperglycemia, hyperlipidemia, and inflammation. Of the plethora of proposed mechanisms, endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and oxidative stress have been shown to play a central role in promoting β cell dysfunction. It has become more evident in recent years that these 3 factors are closely interrelated and importantly aggravate each other. Oxidative stress in particular is of great interest to β cell health and survival as it has been shown that β cells exhibit lower antioxidative capacity. Therefore, this review will focus on discussing factors that contribute to the development of oxidative stress in pancreatic β cells and explore the downstream effects of oxidative stress on β cell function and health. Furthermore, antioxidative capacity of β cells to counteract these effects will be discussed along with new approaches focused on preserving β cells under oxidative conditions.
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Affiliation(s)
- Natsuki Eguchi
- Department of Surgery, University of California, Irvine, CA 92697, USA; (N.E.); (D.C.D.)
| | | | - Donald C. Dafoe
- Department of Surgery, University of California, Irvine, CA 92697, USA; (N.E.); (D.C.D.)
| | - Hirohito Ichii
- Department of Surgery, University of California, Irvine, CA 92697, USA; (N.E.); (D.C.D.)
- Correspondence: ; Tel.: +1-714-456-8590
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Thomas MK, Nikooienejad A, Bray R, Cui X, Wilson J, Duffin K, Milicevic Z, Haupt A, Robins DA. Dual GIP and GLP-1 Receptor Agonist Tirzepatide Improves Beta-cell Function and Insulin Sensitivity in Type 2 Diabetes. J Clin Endocrinol Metab 2021; 106:388-396. [PMID: 33236115 PMCID: PMC7823251 DOI: 10.1210/clinem/dgaa863] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Indexed: 12/11/2022]
Abstract
CONTEXT Novel dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist (RA) tirzepatide demonstrated substantially greater glucose control and weight loss (WL) compared with selective GLP-1RA dulaglutide. OBJECTIVE Explore mechanisms of glucose control by tirzepatide. DESIGN Post hoc analyses of fasting biomarkers and multiple linear regression analysis. SETTING Forty-seven sites in 4 countries. PATIENTS OR OTHER PARTICIPANTS Three hundred and sixteen subjects with type 2 diabetes. INTERVENTIONS Tirzepatide (1, 5, 10, 15 mg), dulaglutide (1.5 mg), placebo. MAIN OUTCOME MEASURES Analyze biomarkers of beta-cell function and insulin resistance (IR) and evaluate WL contributions to IR improvements at 26 weeks. RESULTS Homeostatic model assessment (HOMA) 2-B significantly increased with dulaglutide and tirzepatide 5, 10, and 15 mg compared with placebo (P ≤ .02). Proinsulin/insulin and proinsulin/C-peptide ratios significantly decreased with tirzepatide 10 and 15 mg compared with placebo and dulaglutide (P ≤ .007). Tirzepatide 10 and 15 mg significantly decreased fasting insulin (P ≤ .033) and tirzepatide 10 mg significantly decreased HOMA2-IR (P = .004) compared with placebo and dulaglutide. Markers of improved insulin sensitivity (IS) adiponectin, IGFBP-1, and IGFBP-2 significantly increased by 1 or more doses of tirzepatide (P < .05). To determine whether improvements in IR were directly attributable to WL, multiple linear regression analysis with potential confounding variables age, sex, metformin, triglycerides, and glycated hemoglobin A1c was conducted. WL significantly (P ≤ .028) explained only 13% and 21% of improvement in HOMA2-IR with tirzepatide 10 and 15 mg, respectively. CONCLUSIONS Tirzepatide improved markers of IS and beta-cell function to a greater extent than dulaglutide. IS effects of tirzepatide were only partly attributable to WL, suggesting dual receptor agonism confers distinct mechanisms of glycemic control.
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Affiliation(s)
- Melissa K Thomas
- Eli Lilly and Company, Indianapolis, IN, USA
- Correspondence: Melissa K. Thomas, MD, PhD, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA. E-mail:
| | | | - Ross Bray
- Eli Lilly and Company, Indianapolis, IN, USA
| | - Xuewei Cui
- Eli Lilly and Company, Indianapolis, IN, USA
| | | | | | | | - Axel Haupt
- Eli Lilly and Company, Indianapolis, IN, USA
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Grover A, Sharma K, Gautam S, Gautam S, Gulati M, Singh SK. Diabetes and Its Complications: Therapies Available, Anticipated and Aspired. Curr Diabetes Rev 2021; 17:397-420. [PMID: 33143627 DOI: 10.2174/1573399816666201103144231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/26/2020] [Accepted: 09/12/2020] [Indexed: 11/22/2022]
Abstract
Worldwide, diabetes ranks among the ten leading causes of mortality. Prevalence of diabetes is growing rapidly in low and middle income countries. It is a progressive disease leading to serious co-morbidities, which results in increased cost of treatment and over-all health system of the country. Pathophysiological alterations in Type 2 Diabetes (T2D) progressed from a simple disturbance in the functioning of the pancreas to triumvirate to ominous octet to egregious eleven to dirty dozen model. Due to complex interplay of multiple hormones in T2D, there may be multifaceted approach in its management. The 'long-term secondary complications' in uncontrolled diabetes may affect almost every organ of the body, and finally may lead to multi-organ dysfunction. Available therapies are inconsistent in maintaining long term glycemic control and their long term use may be associated with adverse effects. There is need for newer drugs, not only for glycemic control but also for prevention or mitigation of secondary microvascular and macrovascular complications. Increased knowledge of the pathophysiology of diabetes has contributed to the development of novel treatments. Several new agents like Glucagon Like Peptide - 1 (GLP-1) agonists, Dipeptidyl Peptidase IV (DPP-4) inhibitors, amylin analogues, Sodium-Glucose transport -2 (SGLT- 2) inhibitors and dual Peroxisome Proliferator-Activated Receptor (PPAR) agonists are available or will be available soon, thus extending the range of therapy for T2D, thereby preventing its long term complications. The article discusses the pathophysiology of diabetes along with its comorbidities, with a focus on existing and novel upcoming antidiabetic drugs which are under investigation. It also dives deep to deliberate upon the novel therapies that are in various stages of development. Adding new options with new mechanisms of action to the treatment armamentarium of diabetes may eventually help improve outcomes and reduce its economic burden.
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Affiliation(s)
- Anu Grover
- Ipca Laboratories, Mumbai - 400063, India
| | - Komal Sharma
- Bhupal Nobles' Institute of Pharmaceutical Sciences, Udaipur, India
| | - Suresh Gautam
- Department of Biochemistry, Pacific Institute of Medical Sciences, Udaipur, India
| | - Srishti Gautam
- Ravinder Nath Tagore Medical College and Maharana Bhupal Govt. Hospital, Udaipur, India
| | - Monica Gulati
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab- 144411, India
| | - Sachin Kumar Singh
- School of Pharmaceutical Sciences, Lovely Professional University, Phagwara, Punjab- 144411, India
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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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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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Developmental Programming and Glucolipotoxicity: Insights on Beta Cell Inflammation and Diabetes. Metabolites 2020; 10:metabo10110444. [PMID: 33158303 PMCID: PMC7694373 DOI: 10.3390/metabo10110444] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/23/2020] [Accepted: 10/09/2020] [Indexed: 12/12/2022] Open
Abstract
Stimuli or insults during critical developmental transitions induce alterations in progeny anatomy, physiology, and metabolism that may be transient, sometimes reversible, but often durable, which defines programming. Glucolipotoxicity is the combined, synergistic, deleterious effect of simultaneously elevated glucose (chronic hyperglycemia) and saturated fatty acids (derived from high-fat diet overconsumption and subsequent metabolism) that are harmful to organs, micro-organs, and cells. Glucolipotoxicity induces beta cell death, dysfunction, and failure through endoplasmic reticulum and oxidative stress and inflammation. In beta cells, the misfolding of pro/insulin proteins beyond the cellular threshold triggers the unfolded protein response and endoplasmic reticulum stress. Consequentially there is incomplete and inadequate pro/insulin biosynthesis and impaired insulin secretion. Cellular stress triggers cellular inflammation, where immune cells migrate to, infiltrate, and amplify in beta cells, leading to beta cell inflammation. Endoplasmic reticulum stress reciprocally induces beta cell inflammation, whereas beta cell inflammation can self-activate and further exacerbate its inflammation. These metabolic sequelae reflect the vicious cycle of beta cell stress and inflammation in the pathophysiology of diabetes.
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Zhang R, Shi J, Wang T, Qiu X, Liu R, Li Y, Gao Q, Wang N. Apigetrin ameliorates streptozotocin-induced pancreatic β-cell damages via attenuating endoplasmic reticulum stress. In Vitro Cell Dev Biol Anim 2020; 56:622-634. [PMID: 32901429 DOI: 10.1007/s11626-020-00478-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/29/2020] [Indexed: 02/06/2023]
Abstract
The pathogenesis of diabetes is associated with dysfunction of pancreatic β-cells. To ameliorate the β-cell dysfunction, it has propelled great interest to search pharmacological agents from natural plants. This study explored the protective effect of apigetrin, a flavonoid present in natural plants, against streptozotocin (STZ)-induced cell damages in RINm5F cells and the potential mechanisms. Apigetrin was found to inhibit the elevation of intracellular reactive oxygen species levels, restore the impairment of antioxidant enzymes, and recover the disruption of redox homeostasis in the STZ-treated pancreatic β-cells. Moreover, treatment of apigetrin significantly suppressed the STZ-induced apoptosis in the analysis of apoptotic sub-G1 population and the protein expressions of cleaved poly(ADP-ribose) polymerase and caspase-3. Furthermore, apigetrin attenuated STZ-induced endoplasmic reticulum (ER) stress, indicated by the reduction of ER stress biomarkers, including overloading of mitochondrial calcium, increase in glucose-regulated protein 78, phosphorylation of protein kinase RNA-like ER kinase and its downstream eukaryotic initiation factor 2α, cleavage of activating transcription factor 6 and caspase-12, up-regulation of CCAAT/enhancer binding protein homologous protein, and induction of spliced X-box binding protein 1. Additionally, pretreatment with 4-phenylbutyric acid, a classic ER stress inhibitor, augmented these beneficial effects of apigetrin. In conclusion, these results demonstrated that apigetrin could improve the STZ-induced pancreatic β-cell damages via mitigation of oxidative stress and ER stress and supported the application of apigetrin to developing the novel therapeutics of diabetes.
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Affiliation(s)
- Rui Zhang
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China.
| | - Jie Shi
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China
| | - Tingting Wang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China
| | - Xiaonan Qiu
- Department of Biochemistry, School of Medicine, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China
| | - Ruixia Liu
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China
| | - Yitian Li
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China
| | - Qing Gao
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China
| | - Ning Wang
- School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, Jiangsu, People's Republic of China
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70
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Shrestha N, Reinert RB, Qi L. Endoplasmic Reticulum Protein Quality Control in β Cells. Semin Cell Dev Biol 2020; 103:59-67. [PMID: 32402517 PMCID: PMC7321887 DOI: 10.1016/j.semcdb.2020.04.006] [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] [Received: 12/04/2019] [Revised: 03/17/2020] [Accepted: 04/10/2020] [Indexed: 12/12/2022]
Abstract
Type 1 and type 2 diabetes are associated with loss of β cell function. Optimal β cell function is linked to protein homeostasis in the endoplasmic reticulum (ER). Here, we review the roles of ER protein quality-control mechanisms, including the unfolded protein response (UPR), autophagy (specifically ER-phagy) and ER-associated degradation (ERAD), in β cells. We propose that different quality control mechanisms may control different aspects of β cell biology (i.e. function, survival, and identity), thereby contributing to disease pathogenesis.
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Affiliation(s)
- Neha Shrestha
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Rachel B Reinert
- Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48105, USA; Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48105, USA.
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Khilji MS, Bresson SE, Verstappen D, Pihl C, Andersen PAK, Agergaard JB, Dahlby T, Bryde TH, Klindt K, Nielsen CK, Walentinsson A, Zivkovic D, Bousquet MP, Tyrberg B, Richardson SJ, Morgan NG, Mandrup-Poulsen T, Marzec MT. The inducible β5i proteasome subunit contributes to proinsulin degradation in GRP94-deficient β-cells and is overexpressed in type 2 diabetes pancreatic islets. Am J Physiol Endocrinol Metab 2020; 318:E892-E900. [PMID: 32255680 DOI: 10.1152/ajpendo.00372.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Proinsulin is a misfolding-prone protein, and its efficient breakdown is critical when β-cells are confronted with high-insulin biosynthetic demands, to prevent endoplasmic reticulum stress, a key trigger of secretory dysfunction and, if uncompensated, apoptosis. Proinsulin degradation is thought to be performed by the constitutively expressed standard proteasome, while the roles of other proteasomes are unknown. We recently demonstrated that deficiency of the proinsulin chaperone glucose-regulated protein 94 (GRP94) causes impaired proinsulin handling and defective insulin secretion associated with a compensated endoplasmic reticulum stress response. Taking advantage of this model of restricted folding capacity, we investigated the role of different proteasomes in proinsulin degradation, reasoning that insulin secretory dynamics require an inducible protein degradation system. We show that the expression of only one enzymatically active proteasome subunit, namely, the inducible β5i-subunit, was increased in GRP94 CRISPR/Cas9 knockout (KO) cells. Additionally, the level of β5i-containing intermediate proteasomes was significantly increased in these cells, as was β5i-related chymotrypsin-like activity. Moreover, proinsulin levels were restored in GRP94 KO upon β5i small interfering RNA-mediated knockdown. Finally, the fraction of β-cells expressing the β5i-subunit is increased in human islets from type 2 diabetes patients. We conclude that β5i is an inducible proteasome subunit dedicated to the degradation of mishandled proinsulin.
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Affiliation(s)
- Muhammad Saad Khilji
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sophie Emilie Bresson
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Danielle Verstappen
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Radboud Universiteit, Nijmegen, The Netherlands
| | - Celina Pihl
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Phillip Alexander Keller Andersen
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jette Bach Agergaard
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tina Dahlby
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tenna Holgersen Bryde
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Klindt
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian Kronborg Nielsen
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna Walentinsson
- Translational Science and Experimental Medicine, Early Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Dusan Zivkovic
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, Université de Toulouse, Toulouse, France
| | - Marie-Pierre Bousquet
- Institut de Pharmacologie et de Biologie Structurale, Centre National de la Recherche Scientifique, Université de Toulouse, Toulouse, France
| | - Björn Tyrberg
- Department of Physiology, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Sarah J Richardson
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, United Kingdom
| | - Noel G Morgan
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Exeter, United Kingdom
| | - Thomas Mandrup-Poulsen
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michal Tomasz Marzec
- Laboratory of Immuno-endocrinology, Inflammation, Metabolism, and Oxidation Section, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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Tans R, van Rijswijck DMH, Davidson A, Hannam R, Ricketts B, Tack CJ, Wessels HJCT, Gloerich J, van Gool AJ. Affimers as an alternative to antibodies for protein biomarker enrichment. Protein Expr Purif 2020; 174:105677. [PMID: 32461183 DOI: 10.1016/j.pep.2020.105677] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/15/2020] [Accepted: 05/17/2020] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Assessing the specificity of protein binders is an essential first step in protein biomarker assay development. Affimers are novel protein binders and can potentially replace antibodies in multiple protein capture-based assays. Affimers are selected for their high specificity against the target protein and have benefits over antibodies like batch-to-batch reproducibility and are stable across a wide range of chemical conditions. Here we mimicked a typical initial screening of affimers and commercially available monoclonal antibodies against two non-related proteins, IL-37b and proinsulin, to assess the potential of affimers as alternative to antibodies. METHODS Binding specificity of anti-IL-37b and anti-proinsulin affimers and antibodies was investigated via magnetic bead-based capture of their recombinant protein targets in human plasma. Captured proteins were analyzed using SDS-PAGE, Coomassie blue staining, Western blotting and LC-MS/MS-based proteomics. RESULTS All affimers and antibodies were able to bind their target protein in human plasma. Gel and LC-MS/MS analysis showed that both affimer and antibody-based captures resulted in co-purified background proteins. However, affimer-based captures showed the highest relative enrichment of IL-37b and proinsulin. CONCLUSIONS For both proteins tested, affimers show higher specificity in purifying their target proteins from human plasma compared to monoclonal antibodies. These results indicate that affimers are promising antibody-replacement tools for protein biomarker assay development.
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Affiliation(s)
- Roel Tans
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Danique M H van Rijswijck
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Alex Davidson
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Ryan Hannam
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Bryon Ricketts
- Avacta Life Sciences, Unit 20, Ash Way, Thorp Arch Estate & Retail Park, Wetherby, LS23 7FA, United Kingdom
| | - Cees J Tack
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Hans J C T Wessels
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Jolein Gloerich
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands
| | - Alain J van Gool
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, the Netherlands.
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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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74
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Hu R, Walker E, Huang C, Xu Y, Weng C, Erickson GE, Coldren A, Yang X, Brissova M, Kaverina I, Balamurugan AN, Wright CVE, Li Y, Stein R, Gu G. Myt Transcription Factors Prevent Stress-Response Gene Overactivation to Enable Postnatal Pancreatic β Cell Proliferation, Function, and Survival. Dev Cell 2020; 53:390-405.e10. [PMID: 32359405 PMCID: PMC7278035 DOI: 10.1016/j.devcel.2020.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 03/06/2020] [Accepted: 04/03/2020] [Indexed: 02/06/2023]
Abstract
Although cellular stress response is important for maintaining function and survival, overactivation of late-stage stress effectors cause dysfunction and death. We show that the myelin transcription factors (TFs) Myt1 (Nzf2), Myt2 (Myt1l, Nztf1, and Png-1), and Myt3 (St18 and Nzf3) prevent such overactivation in islet β cells. Thus, we found that co-inactivating the Myt TFs in mouse pancreatic progenitors compromised postnatal β cell function, proliferation, and survival, preceded by upregulation of late-stage stress-response genes activating transcription factors (e.g., Atf4) and heat-shock proteins (Hsps). Myt1 binds putative enhancers of Atf4 and Hsps, whose overexpression largely recapitulated the Myt-mutant phenotypes. Moreover, Myt(MYT)-TF levels were upregulated in mouse and human β cells during metabolic stress-induced compensation but downregulated in dysfunctional type 2 diabetic (T2D) human β cells. Lastly, MYT knockdown caused stress-gene overactivation and death in human EndoC-βH1 cells. These findings suggest that Myt TFs are essential restrictors of stress-response overactivity.
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Affiliation(s)
- Ruiying Hu
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Emily Walker
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Chen Huang
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yanwen Xu
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Chen Weng
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Gillian E Erickson
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Anastasia Coldren
- Department of Medicine, Vanderbilt Medical Center, Nashville, TN 27232, USA
| | - Xiaodun Yang
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Marcela Brissova
- Department of Medicine, Vanderbilt Medical Center, Nashville, TN 27232, USA
| | - Irina Kaverina
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Appakalai N Balamurugan
- Department of Surgery, Clinical Islet Transplantation Laboratory, Cardiovascular Innovation Institute, University of Louisville, Louisville, KY 40202, USA
| | - Christopher V E Wright
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Yan Li
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Guoqiang Gu
- Vanderbilt Program in Developmental Biology, Department of Cell and Developmental Biology, and Center for Stem Cell Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Shergalis AG, Hu S, Bankhead A, Neamati N. Role of the ERO1-PDI interaction in oxidative protein folding and disease. Pharmacol Ther 2020; 210:107525. [PMID: 32201313 DOI: 10.1016/j.pharmthera.2020.107525] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/04/2020] [Accepted: 02/19/2020] [Indexed: 02/06/2023]
Abstract
Protein folding in the endoplasmic reticulum is an oxidative process that relies on protein disulfide isomerase (PDI) and endoplasmic reticulum oxidase 1 (ERO1). Over 30% of proteins require the chaperone PDI to promote disulfide bond formation. PDI oxidizes cysteines in nascent polypeptides to form disulfide bonds and can also reduce and isomerize disulfide bonds. ERO1 recycles reduced PDI family member PDIA1 using a FAD cofactor to transfer electrons to oxygen. ERO1 dysfunction critically affects several diseases states. Both ERO1 and PDIA1 are overexpressed in cancers and implicated in diabetes and neurodegenerative diseases. Cancer-associated ERO1 promotes cell migration and invasion. Furthermore, the ERO1-PDIA1 interaction is critical for epithelial-to-mesenchymal transition. Co-expression analysis of ERO1A gene expression in cancer patients demonstrated that ERO1A is significantly upregulated in lung adenocarcinoma (LUAD), glioblastoma and low-grade glioma (GBMLGG), pancreatic ductal adenocarcinoma (PAAD), and kidney renal papillary cell carcinoma (KIRP) cancers. ERO1Α knockdown gene signature correlates with knockdown of cancer signaling proteins including IGF1R, supporting the search for novel, selective ERO1 inhibitors for the treatment of cancer. In this review, we explore the functions of ERO1 and PDI to support inhibition of this interaction in cancer and other diseases.
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Affiliation(s)
- Andrea G Shergalis
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Rogel Cancer Center, Ann Arbor, MI 48109, United States
| | - Shuai Hu
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Rogel Cancer Center, Ann Arbor, MI 48109, United States; Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Armand Bankhead
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, United States; Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, MI 48109, United States
| | - Nouri Neamati
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Rogel Cancer Center, Ann Arbor, MI 48109, United States.
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76
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Yi X, Cai X, Wang S, Xiao Y. Mechanisms of impaired pancreatic β‑cell function in high‑fat diet‑induced obese mice: The role of endoplasmic reticulum stress. Mol Med Rep 2020; 21:2041-2050. [PMID: 32323766 PMCID: PMC7115219 DOI: 10.3892/mmr.2020.11013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 11/11/2019] [Indexed: 12/29/2022] Open
Abstract
The aim of the study was to examine whether there was excessive endoplasmic reticulum stress (ERs) in the islets of high-fat diet (HFD)-induced obese mice, as well as the effects of ERs on β-cell function. Male C57BL/6J mice were fed a HFD for 16 weeks. Pancreatic β-cell function was evaluated using intraperitoneal glucose tolerance and insulin release tests, and via electron microscopy. The expression of activating transcription factor 6 (ATF6) and phosphorylated (p)-eukaryotic initiation factor 2α (eIF2α) were detected via immunofluorescence staining to determine whether exposure to a HFD induced ERs in pancreatic islets. In vitro, ERs was induced by palmitate (PA) in INS-1 cells, and the protein expression of ATF6, and mRNA expression of ATF6 and insulin were examined via western blot and quantitative PCR (qPCR) analyses, respectively. The nuclear localization of ATF6 was examined by immunofluorescence. Finally, small interfering (si)RNA was used to downregulate ATF6 expression in INS-1 cells to further determine whether ATF6 mediated the ERs-induced impairment of insulin gene transcription. After 16 weeks of induction, the obese mice showed impaired glucose tolerance, insulin resistance and hyperinsulinemia. Immunohistochemistry staining showed increased p-eIF2α and ATF6 expression in pancreatic islets in the obesity group compared with the normal group. Electron microscopy indicated that the microstructures and secretory functions of β-cells were impaired. After 24 h of incubation, ATF mRNA and protein expression in the PA group was significantly higher compared with the control group. However, the insulin mRNA expression in the PA group was significantly decreased. Furthermore, qPCR showed that the insulin mRNA expression was significantly increased 24 h after PA treatment in cells transfected with ATF6-siRNA compared with the negative control group. The present suggested shows that ERs-induced activation of ATF6 may play an important role in the development of β-cell dysfunction in obese mice.
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Affiliation(s)
- Xiaoqing Yi
- Department of Pediatrics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Xuan Cai
- Department of Pediatrics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Sisi Wang
- Department of Pediatrics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
| | - Yanfeng Xiao
- Department of Pediatrics, Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, P.R. China
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77
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Zhang IX, Raghavan M, Satin LS. The Endoplasmic Reticulum and Calcium Homeostasis in Pancreatic Beta Cells. Endocrinology 2020; 161:bqz028. [PMID: 31796960 PMCID: PMC7028010 DOI: 10.1210/endocr/bqz028] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 12/01/2019] [Indexed: 12/14/2022]
Abstract
The endoplasmic reticulum (ER) mediates the first steps of protein assembly within the secretory pathway and is the site where protein folding and quality control are initiated. The storage and release of Ca2+ are critical physiological functions of the ER. Disrupted ER homeostasis activates the unfolded protein response (UPR), a pathway which attempts to restore cellular equilibrium in the face of ER stress. Unremitting ER stress, and insufficient compensation for it results in beta-cell apoptosis, a process that has been linked to both type 1 diabetes (T1D) and type 2 diabetes (T2D). Both types are characterized by progressive beta-cell failure and a loss of beta-cell mass, although the underlying causes are different. The reduction of mass occurs secondary to apoptosis in the case of T2D, while beta cells undergo autoimmune destruction in T1D. In this review, we examine recent findings that link the UPR pathway and ER Ca2+ to beta cell dysfunction. We also discuss how UPR activation in beta cells favors cell survival versus apoptosis and death, and how ER protein chaperones are involved in regulating ER Ca2+ levels. Abbreviations: BiP, Binding immunoglobulin Protein ER; endoplasmic reticulum; ERAD, ER-associated protein degradation; IFN, interferon; IL, interleukin; JNK, c-Jun N-terminal kinase; KHE, proton-K+ exchanger; MODY, maturity-onset diabetes of young; PERK, PRKR-like ER kinase; SERCA, Sarco/Endoplasmic Reticulum Ca2+-ATPases; T1D, type 1 diabetes; T2D, type 2 diabetes; TNF, tumor necrosis factor; UPR, unfolded protein response; WRS, Wolcott-Rallison syndrome.
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Affiliation(s)
- Irina X Zhang
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan, Ann Arbor, MI
| | - Malini Raghavan
- Department of Microbiology and Immunology Michigan Medicine, University of Michigan, Ann Arbor, MI
| | - Leslie S Satin
- Department of Pharmacology and Brehm Diabetes Research Center, University of Michigan, Ann Arbor, MI
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78
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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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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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80
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Aivazidis S, Jain A, Rauniyar AK, Anderson CC, Marentette JO, Orlicky DJ, Fritz KS, Harris PS, Siegel D, Maclean KN, Roede JR. SNARE proteins rescue impaired autophagic flux in Down syndrome. PLoS One 2019; 14:e0223254. [PMID: 31714914 PMCID: PMC6850524 DOI: 10.1371/journal.pone.0223254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/17/2019] [Indexed: 01/20/2023] Open
Abstract
Down syndrome (DS) is a chromosomal disorder caused by trisomy of chromosome 21 (Ts21). Unbalanced karyotypes can lead to dysfunction of the proteostasis network (PN) and disrupted proteostasis is mechanistically associated with multiple DS comorbidities. Autophagy is a critical component of the PN that has not previously been investigated in DS. Based on our previous observations of PN disruption in DS, we investigated possible dysfunction of the autophagic machinery in human DS fibroblasts and other DS cell models. Following induction of autophagy by serum starvation, DS fibroblasts displayed impaired autophagic flux indicated by autophagolysosome accumulation and elevated p62, NBR1, and LC3-II abundance, compared to age- and sex-matched, euploid (CTL) fibroblasts. While lysosomal physiology was unaffected in both groups after serum starvation, we observed decreased basal abundance of the Soluble N-ethylmaleimide-sensitive-factor Attachment protein Receptor (SNARE) family members syntaxin 17 (STX17) and Vesicle Associated Membrane Protein 8 (VAMP8) indicating that decreased autophagic flux in DS is due at least in part to a possible impairment of autophagosome-lysosome fusion. This conclusion was further supported by the observation that over-expression of either STX17 or VAMP8 in DS fibroblasts restored autophagic degradation and reversed p62 accumulation. Collectively, our results indicate that impaired autophagic clearance is a characteristic of DS cells that can be reversed by enhancement of SNARE protein expression and provides further evidence that PN disruption represents a candidate mechanism for multiple aspects of pathogenesis in DS and a possible future target for therapeutic intervention.
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Affiliation(s)
- Stefanos Aivazidis
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Abhilasha Jain
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Abhishek K. Rauniyar
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Colin C. Anderson
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - John O. Marentette
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - David J. Orlicky
- Department of Pathology, University of Colorado School of Medicine, Aurora, CO, United States of America
| | - Kristofer S. Fritz
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Peter S. Harris
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - David Siegel
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
| | - Kenneth N. Maclean
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States of America
- The Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO, United States of America
| | - James R. Roede
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, United States of America
- The Linda Crnic Institute for Down Syndrome, University of Colorado, Aurora, CO, United States of America
- * E-mail:
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Yang Y, Wang M, Tong J, Dong Z, Deng M, Ren X, Li H, Yang J, Meng Z, Sun J, He Q, Liu M. Impaired Glucose-Stimulated Proinsulin Secretion Is an Early Marker of β-Cell Impairment Before Prediabetes Stage. J Clin Endocrinol Metab 2019; 104:4341-4346. [PMID: 31074785 DOI: 10.1210/jc.2019-00549] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/06/2019] [Indexed: 01/09/2023]
Abstract
CONTEXT Evidence indicates that there is substantial impairment/loss of β-cell function/mass even before prediabetes. Elevated plasma proinsulin is a sign of β-cell dysfunction in patients with diabetes/prediabetes. However, the dynamic changes of glucose stimulated proinsulin secretion (GSPS) among nondiabetic individuals remain obscure. OBJECTIVE To examine GSPS and glucose-stimulated insulin secretion (GSIS) among individuals with normal glucose tolerance (NGT) and impaired glucose tolerance (IGT) and to evaluate whether impaired GSPS is an early biomarker of β-cell impairment in individuals with NGT who have subthreshold postprandial plasma glucose (PPG). DESIGN AND PARTICIPANTS We evaluated GSPS and GSIS in 116 Chinese adults without diabetes (mean age ± SD, 33.31 ± 9.10 years; mean BMI, 25.24 ± 4.20 kg/m2) with fasting plasma glucose (FPG) < 5.6 mmol/L. Based on 2hPPG, the participants were divided into three groups: NGT1 (2hPPG < 6.67 mmol/L), NGT2 (6.67 ≤ 2hPPG < 7.78 mmol/L), and IGT (7.78 ≤ 2hPPG<11.1 mmol/L). We analyzed the association of GSIS and GSPS with commonly used indexes of β-cell function, insulin resistance and family history of diabetes. RESULTS Although not diagnosed with prediabetes, the individuals with NGT2 have clinical characteristics and high diabetes risk factors similar to those of the IGT group. However, unlike individuals with IGT, NGT2 participants did not exhibit a delayed GSIS. Instead, GSPS was impaired in NGT2 groups but not in NGT1 group. CONCLUSIONS This study suggests that impaired GSPS, but not impaired GSIS, may serve as an early biomarker to identify a subpopulation of NGT with a high risk of diabetes.
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Affiliation(s)
- Ying Yang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Min Wang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Jingzhi Tong
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Zuoliang Dong
- Department of Medical Laboratory, Tianjin Medical University General Hospital, Tianjin, China
| | - Min Deng
- Department of Physical Examination, Tianjin Electric Power Hospital, Tianjin, China
| | - Xiaojun Ren
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Hui 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
| | - Zhaowei Meng
- Department of Nuclear Medicine, Tianjin Medical University General Hospital, Tianjin, China
| | - Jinhong Sun
- Department of Health Management, Tianjin Medical University General Hospital, Tianjin, China
| | - Qing He
- 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
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Relationship Between Oxidative Stress, ER Stress, and Inflammation in Type 2 Diabetes: The Battle Continues. J Clin Med 2019; 8:jcm8091385. [PMID: 31487953 PMCID: PMC6780404 DOI: 10.3390/jcm8091385] [Citation(s) in RCA: 292] [Impact Index Per Article: 58.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/29/2019] [Accepted: 09/02/2019] [Indexed: 12/15/2022] Open
Abstract
Type 2 diabetes (T2D) is a metabolic disorder characterized by hyperglycemia and insulin resistance in which oxidative stress is thought to be a primary cause. Considering that mitochondria are the main source of ROS, we have set out to provide a general overview on how oxidative stress is generated and related to T2D. Enhanced generation of reactive oxygen species (ROS) and oxidative stress occurs in mitochondria as a consequence of an overload of glucose and oxidative phosphorylation. Endoplasmic reticulum (ER) stress plays an important role in oxidative stress, as it is also a source of ROS. The tight interconnection between both organelles through mitochondrial-associated membranes (MAMs) means that the ROS generated in mitochondria promote ER stress. Therefore, a state of stress and mitochondrial dysfunction are consequences of this vicious cycle. The implication of mitochondria in insulin release and the exposure of pancreatic β-cells to hyperglycemia make them especially susceptible to oxidative stress and mitochondrial dysfunction. In fact, crosstalk between both mechanisms is related with alterations in glucose homeostasis and can lead to the diabetes-associated insulin-resistance status. In the present review, we discuss the current knowledge of the relationship between oxidative stress, mitochondria, ER stress, inflammation, and lipotoxicity in T2D.
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83
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Sankrityayan H, Oza MJ, Kulkarni YA, Mulay SR, Gaikwad AB. ER stress response mediates diabetic microvascular complications. Drug Discov Today 2019; 24:2247-2257. [PMID: 31430543 DOI: 10.1016/j.drudis.2019.08.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 07/19/2019] [Accepted: 08/01/2019] [Indexed: 12/16/2022]
Abstract
Endoplasmic reticulum (ER) homeostasis orchestrates the folding, modification, and trafficking of secretory and membrane proteins to the Golgi compartment, thus governing cellular functions. Alterations in ER homeostasis result in the activation of signaling pathways, such as the unfolded protein response (UPR), to regain ER homeostasis. Nevertheless, failure of UPR leads to activation of autophagy-mediated cell death. Several recent studies emphasized the association of the ER stress (ERS) response with the initiation and progression of diabetes. In this review, we highlight the contribution of the ERS response, such as UPR and autophagy, in the initiation and progression of diabetes and associated microvascular complications, including diabetic nephropathy (DN), retinopathy, and neuropathy, in various experimental models, as well as in humans. We highlight the ERS as a putative therapeutic target for the treatment of diabetic microvascular complications and, thus, the urgent need for the development of improved synthetic and natural inhibitors of ERS.
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Affiliation(s)
- Himanshu Sankrityayan
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India
| | - Manisha J Oza
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS, V.L. Mehta Road, Vile Parle (W), Mumbai 400056, India; SVKM's Dr Bhanuben Nanavati College of Pharmacy, Vile Parle (W), Mumbai 400056, India
| | - Yogesh A Kulkarni
- Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS, V.L. Mehta Road, Vile Parle (W), Mumbai 400056, India
| | - Shrikant R Mulay
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Anil Bhanudas Gaikwad
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science Pilani, Pilani Campus, Rajasthan 333031, India.
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84
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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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85
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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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86
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Lysosomal degradation of newly formed insulin granules contributes to β cell failure in diabetes. Nat Commun 2019; 10:3312. [PMID: 31346174 PMCID: PMC6658524 DOI: 10.1038/s41467-019-11170-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 06/27/2019] [Indexed: 02/06/2023] Open
Abstract
Compromised function of insulin-secreting pancreatic β cells is central to the development and progression of Type 2 Diabetes (T2D). However, the mechanisms underlying β cell failure remain incompletely understood. Here, we report that metabolic stress markedly enhances macroautophagy-independent lysosomal degradation of nascent insulin granules. In different model systems of diabetes including of human origin, stress-induced nascent granule degradation (SINGD) contributes to loss of insulin along with mammalian/mechanistic Target of Rapamycin (mTOR)-dependent suppression of macroautophagy. Expression of Protein Kinase D (PKD), a negative regulator of SINGD, is reduced in diabetic β cells. Pharmacological activation of PKD counters SINGD and delays the onset of T2D. Conversely, inhibition of PKD exacerbates SINGD, mitigates insulin secretion and accelerates diabetes. Finally, reduced levels of lysosomal tetraspanin CD63 prevent SINGD, leading to increased insulin secretion. Overall, our findings implicate aberrant SINGD in the pathogenesis of diabetes and suggest new therapeutic strategies to prevent β cell failure. Impaired beta-cell insulin secretion is a key pathological feature of type 2 diabetes. Here, the authors describe metabolic stress induced lysosomal degradation of newly formed insulin granules, independent of macroautophagy, as a potential mechanism for beta-cell dysfunction.
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87
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Vakilian M, Tahamtani Y, Ghaedi K. A review on insulin trafficking and exocytosis. Gene 2019; 706:52-61. [DOI: 10.1016/j.gene.2019.04.063] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/22/2019] [Accepted: 04/23/2019] [Indexed: 12/21/2022]
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88
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Dunne JL, Richardson SJ, Atkinson MA, Craig ME, Dahl-Jørgensen K, Flodström-Tullberg M, Hyöty H, Lloyd RE, Morgan NG, Pugliese A. Large enteroviral vaccination studies to prevent type 1 diabetes should be well founded and rely on scientific evidence. Reply to Skog O, Klingel K, Roivainen M et al [letter]. Diabetologia 2019; 62:1100-1103. [PMID: 31016358 DOI: 10.1007/s00125-019-4873-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 03/20/2019] [Indexed: 12/15/2022]
Affiliation(s)
| | - Sarah J Richardson
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, RILD Building, Barrack Road, Exeter, EX2 5DW, UK.
| | - Mark A Atkinson
- Departments of Pathology and Pediatrics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Maria E Craig
- School of Women's and Children's Health, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Knut Dahl-Jørgensen
- Department of Pediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Malin Flodström-Tullberg
- Center for Infectious Medicine, Department of Medicine Huddinge, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
| | - Heikki Hyöty
- Faculty of Medicine and Life Sciences, University of Tampere, Tampere, Finland
- Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland
| | - Richard E Lloyd
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Noel G Morgan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, RILD Building, Barrack Road, Exeter, EX2 5DW, UK
| | - Alberto Pugliese
- Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Microbiology and Immunology, Miller School of Medicine, University of Miami, Miami, FL, USA
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89
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Hu Y, Gao Y, Zhang M, Deng KY, Singh R, Tian Q, Gong Y, Pan Z, Liu Q, Boisclair YR, Long Q. Endoplasmic Reticulum-Associated Degradation (ERAD) Has a Critical Role in Supporting Glucose-Stimulated Insulin Secretion in Pancreatic β-Cells. Diabetes 2019; 68:733-746. [PMID: 30626610 DOI: 10.2337/db18-0624] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 12/19/2018] [Indexed: 11/13/2022]
Abstract
The molecular underpinnings of β-cell dysfunction and death leading to diabetes are not fully elucidated. The objective of the current study was to investigate the role of endoplasmic reticulum-associated degradation (ERAD) in pancreatic β-cells. Chemically induced ERAD deficiency in the rat insulinoma cell line INS-1 markedly reduced glucose-stimulated insulin secretion (GSIS). The mechanistic basis for this effect was studied in cells and mice lacking ERAD as a consequence of genetic ablation of the core ERAD protein SEL1L. Targeted disruption of SEL1L in INS-1 cells and in mouse pancreatic β-cells impaired ERAD and led to blunted GSIS. Additionally, mice with SEL1L deletion in β-cells were chronically hyperglycemic after birth and increasingly glucose intolerant over time. SEL1L absence caused an entrapment of proinsulin in the endoplasmic reticulum compartment in both INS-1 cells and mouse pancreatic β-cells. Both folding-competent and folding-deficient proinsulin can physiologically interact with and be efficiently degraded by HRD1, the E3 ubiquitin ligase subunit of the ERAD complex. GSIS impairment in insulinoma cells was accompanied by a reduced intracellular Ca2+ ion level, overproduction of reactive oxygen species, and lowered mitochondrial membrane potential. Together, these findings suggest that ERAD plays a pivotal role in supporting pancreatic β-cell function by targeting wild-type and folding-deficient proinsulin for proteosomal degradation. ERAD deficiency may contribute to the development of diabetes by affecting proinsulin processing in the ER, intracellular Ca2+ concentration, and mitochondrial function.
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Affiliation(s)
- Yabing Hu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Yuanyuan Gao
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Manman Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Ke-Yu Deng
- Institute of Translational Medicine, Nanchang University, Nanchang, People's Republic of China
| | - Rajni Singh
- Department of Animal Science, Cornell University, Ithaca, NY
| | - Qiongge Tian
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Yi Gong
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Zhixiong Pan
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | - Qingqing Liu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
| | | | - Qiaoming Long
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Cam-Su Genomic Resource Center, Medical College of Soochow University, Suzhou, People's Republic of China
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90
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Aivazidis S, Anderson CC, Roede JR. Toxicant-mediated redox control of proteostasis in neurodegeneration. CURRENT OPINION IN TOXICOLOGY 2019; 13:22-34. [PMID: 31602419 PMCID: PMC6785977 DOI: 10.1016/j.cotox.2018.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Disruption in redox signaling and control of cellular processes has emerged as a key player in many pathologies including neurodegeneration. As protein aggregations are a common hallmark of several neuronal pathologies, a firm understanding of the interplay between redox signaling, oxidative and free radical stress, and proteinopathies is required to sort out the complex mechanisms in these diseases. Fortunately, models of toxicant-induced neurodegeneration can be utilized to evaluate and report mechanistic alterations in the proteostasis network (PN). The epidemiological links between environmental toxicants and neurological disease gives further credence into characterizing the toxicant-mediated PN disruptions observed in these conditions. Reviewed here are examples of mechanistic interaction between oxidative or free radical stress and PN alterations. Additionally, investigations into toxicant-mediated PN disruptions, specifically focusing on environmental metals and pesticides, are discussed. Finally, we emphasize the need to distinguish whether the presence of protein aggregations are contributory to phenotypes related to neurodegeneration, or if they are a byproduct of PN deficiencies.
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Affiliation(s)
- Stefanos Aivazidis
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Colin C Anderson
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - James R Roede
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
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91
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Bioluminescent reporter assay for monitoring ER stress in human beta cells. Sci Rep 2018; 8:17738. [PMID: 30532033 PMCID: PMC6288136 DOI: 10.1038/s41598-018-36142-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 11/13/2018] [Indexed: 12/17/2022] Open
Abstract
During type 1 diabetes development, cells in the islets of Langerhans engage adaptive mechanisms in response to inflammatory signals to cope with stress, to restore cellular homeostasis, and to preserve cell function. Disruption of these mechanisms may induce the formation of a repertoire of stress-induced neoantigens, which are critical in the loss of tolerance to beta cells and the development of autoimmunity. While multiple lines of evidence argue for a critical role of the endoplasmic reticulum in these processes, the lack of tools to specifically monitor beta cell stress hampers the development of therapeutic interventions focusing on maintaining endoplasmic reticulum homeostasis. Here we designed and evaluated a stress-induced reporter in which induction of stress correlates with increased light emission. This Gaussia luciferase-based reporter system employs the unconventional cytoplasmic splicing of XBP1 to report ER stress in cells exposed to known ER-stress inducers. Linking this reporter to a human beta cell-specific promotor allows tracing ER-stress in isolated human beta cells as well as in the EndoC-βH1 cell line. This reporter system represents a valuable tool to assess ER stress in human beta cells and may aid the identification of novel therapeutics that can prevent beta cell stress in human pancreatic islets.
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92
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Arasi FP, Shahrestanaki MK, Aghaei M. A2a adenosine receptor agonist improves endoplasmic reticulum stress in MIN6 cell line through protein kinase A/ protein kinase B/ Cyclic adenosine monophosphate response element-binding protein/ and Growth Arrest And DNA-Damage-Inducible 34/ eukaryotic Initiation Factor 2α pathways. J Cell Physiol 2018; 234:10500-10511. [PMID: 30417358 DOI: 10.1002/jcp.27719] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 10/16/2018] [Indexed: 02/06/2023]
Abstract
Endoplasmic reticulum (ER) stress is one of the main molecular events underlying pancreatic beta cell (PBC) failure, apoptosis, and a decrease in insulin secretion. Recent studies have highlighted the fundamental role of A2a adenosine receptor (A2aR) in potentiation of insulin secretion and proliferation of PBCs. However, possible protective effects of A2aR signaling against ER stress have not been elucidated yet. Thus, in the present study, we aimed to investigate the effects of A2aR activation in MIN6 beta cells undergoing tunicamycin (TM)-mediated ER stress. A2aR expression and activity were evaluated using real-time polymerase chain reaction and measurement of the cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), phospho-protein kinase B or Akt (p-Akt)/Akt, and phospho-Cyclic adenosine monophosphate response element-binding protein/CREB levels in response to a specific agonist (CGS 21680). Survival and proliferation in TM and CGS 21680 cotreated cells were evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), annexin V-fluorescein isothiocyanate (FITC)/propidium iodide staining, colony formation, and 5-bromo-2'-deoxyuridine (Brdu) assays. In addition, the effects of A2aR stimulation on insulin secretion were evaluated using the enzyme-linked immunosorbent assay. B-cell lymphoma 2 (Bcl-2), phospho-eukaryotic Initiation Factor 2α (p-eIF2α)/eIF2α, growth arrest and DNA-damage-inducible 34 (GADD34), X-box binding protein 1 (XBP-1), spliced X-box binding protein 1 (XBP-1s), immunoglobulin heavy-chain-binding protein (BIP), and CCAAT-enhancer-binding protein homologous protein (CHOP) levels were evaluated using western blotting. Our results showed a decrease in A2aR expression and p-Akt/Akt and p-CREB/CREB levels in TM-pretreated cells. We also mentioned that CGS 21680 effectively increased cell survival, proliferation, and insulin secretion in TM-treated cells. The antiapoptotic effects were possibly mediated through Bcl-2 upregulation. Our western blotting results indicated that A2aR effectively downregulated p-eIF2α/eIF2α, XBP-1, XBP-1s, BIP, and CHOP levels, whereas GADD34 was upregulated. Altogether, the present study revealed that A2aR signaling through PKA/Akt/CREB mediators alleviated TM cytotoxicity effects in MIN6 beta cells. Thus, the stimulation of this receptor was seen as a new approach to control ER stress in the PBC cells.
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Affiliation(s)
- Fatemeh P Arasi
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mohammad K Shahrestanaki
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahmoud Aghaei
- Department of Clinical Biochemistry, School of Pharmacy & Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, Iran
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93
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Ostrovskaya RU, Ivanov SV, Voronin MV, Ozerova IV, Zolotov NN, Seredenin SB. Antidiabetic Activity of Afobazole in Wistar Rats. Bull Exp Biol Med 2018; 165:649-652. [DOI: 10.1007/s10517-018-4233-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Indexed: 12/15/2022]
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94
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Liu M, Weiss MA, Arunagiri A, Yong J, Rege N, Sun J, Haataja L, Kaufman RJ, Arvan P. Biosynthesis, structure, and folding of the insulin precursor protein. Diabetes Obes Metab 2018; 20 Suppl 2:28-50. [PMID: 30230185 PMCID: PMC6463291 DOI: 10.1111/dom.13378] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/04/2018] [Accepted: 05/23/2018] [Indexed: 02/06/2023]
Abstract
Insulin synthesis in pancreatic β-cells is initiated as preproinsulin. Prevailing glucose concentrations, which oscillate pre- and postprandially, exert major dynamic variation in preproinsulin biosynthesis. Accompanying upregulated translation of the insulin precursor includes elements of the endoplasmic reticulum (ER) translocation apparatus linked to successful orientation of the signal peptide, translocation and signal peptide cleavage of preproinsulin-all of which are necessary to initiate the pathway of proper proinsulin folding. Evolutionary pressures on the primary structure of proinsulin itself have preserved the efficiency of folding ("foldability"), and remarkably, these evolutionary pressures are distinct from those protecting the ultimate biological activity of insulin. Proinsulin foldability is manifest in the ER, in which the local environment is designed to assist in the overall load of proinsulin folding and to favour its disulphide bond formation (while limiting misfolding), all of which is closely tuned to ER stress response pathways that have complex (beneficial, as well as potentially damaging) effects on pancreatic β-cells. Proinsulin misfolding may occur as a consequence of exuberant proinsulin biosynthetic load in the ER, proinsulin coding sequence mutations, or genetic predispositions that lead to an altered ER folding environment. Proinsulin misfolding is a phenotype that is very much linked to deficient insulin production and diabetes, as is seen in a variety of contexts: rodent models bearing proinsulin-misfolding mutants, human patients with Mutant INS-gene-induced Diabetes of Youth (MIDY), animal models and human patients bearing mutations in critical ER resident proteins, and, quite possibly, in more common variety type 2 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Michael A. Weiss
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202 IN USA
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Jing Yong
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Nischay Rege
- Department of Biochemistry, Case-Western Reserve University, Cleveland 44016 OH USA
| | - Jinhong Sun
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China 300052
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
| | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92307 USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan Medical School, Ann Arbor 48105 MI USA
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95
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Weiss MA, Lawrence MC. A thing of beauty: Structure and function of insulin's "aromatic triplet". Diabetes Obes Metab 2018; 20 Suppl 2:51-63. [PMID: 30230175 PMCID: PMC6159917 DOI: 10.1111/dom.13402] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 05/25/2018] [Accepted: 05/31/2018] [Indexed: 12/30/2022]
Abstract
The classical crystal structure of insulin was determined in 1969 by D.C. Hodgkin et al. following a 35-year program of research. This structure depicted a hexamer remarkable for its self-assembly as a zinc-coordinated trimer of dimer. Prominent at the dimer interface was an "aromatic triplet" of conserved residues at consecutive positions in the B chain: PheB24 , PheB25 and TyrB26 . The elegance of this interface inspired the Oxford team to poetry: "A thing of beauty is a joy forever" (John Keats as quoted by Blundell, T.L., et al. Advances in Protein Chemistry 26:279-286 [1972]). Here, we revisit this aromatic triplet in light of recent advances in the structural biology of insulin bound as a monomer to fragments of the insulin receptor. Such co-crystal structures have defined how these side chains pack at the primary hormone-binding surface of the receptor ectodomain. On receptor binding, the B-chain β-strand (residues B24-B28) containing the aromatic triplet detaches from the α-helical core of the hormone. Whereas TyrB26 lies at the periphery of the receptor interface and may functionally be replaced by a diverse set of substitutions, PheB24 and PheB25 engage invariant elements of receptor domains L1 and αCT. These critical contacts were anticipated by the discovery of diabetes-associated mutations at these positions by Donald Steiner et al. at the University of Chicago. Conservation of PheB24 , PheB25 and TyrB26 among vertebrate insulins reflects the striking confluence of structure-based evolutionary constraints: foldability, protective self-assembly and hormonal activity.
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Affiliation(s)
- Michael A. Weiss
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202 USA
| | - Michael C. Lawrence
- The Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Victoria 3052, AUSTRALIA
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, AUSTRALIA
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96
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Dong Y, Li S, Zhao W, Wang Y, Ge T, Xiao J, Li Y. Changes of MODY signal pathway genes in the endoplasmic reticulum stress in INS-1-3 cells. PLoS One 2018; 13:e0198614. [PMID: 29879176 PMCID: PMC5991669 DOI: 10.1371/journal.pone.0198614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 05/22/2018] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Metabolic disturbances induce endoplasmic reticulum stress (ERS) in pancreatic beta cells. This study aims to investigate whether a common pathway exists in the ERS induced by various chemicals, including high levels of glucose and palmitate in INS-1-3 cells. METHOD ERS in INS-1-3 cells was induced by exposure cells to thapsigargin (TG), tunicamycin (TM) or palmitic acid (PA) +high glucose (HG). Digital gene expression (DGE) profiling technique was used to detect differentially expressed genes. The profile of gene expression was detected by gene oncology (GO) function and pathway enrichment analysis. Nkx6.1 over-expression was established in INS-1-3 cell lines by lentivirus infection to revert the inhibition of Nkx6.1 expression found in the situation of ERS. Real time reverse transcription polymerase chain reaction (RT-PCR) was used to verify the expression changes of key genes. Cell viability was measured by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. The apoptosis was determined by flow cytometry. INS-1-3 cell function was measured by glucose stimulated insulin secretion test(GSIS). RESULTS As compared to control, DGE demonstrated that there were 135, 57 and 74 differentially expressed genes in TM, TG and HG+PA groups, respectively. Those differentially expressed genes were enriched to ERS, antigen processing and presentation, protein export pathways, and interestingly, the maturity onset diabetes of the young (MODY) pathway. Nkx6.1 is one of common down-regulated gene in MODY signaling pathway among TM, TG and HG+PA groups. Over-expression of Nkx6.1 ameliorated glucolipotoxicity induced apoptosis rate by 45.4%, and increased proliferation by 40.9%. At the same time, GSIS increased by 1.82 folds. CONCLUSIONS MODY pathway genes expression was changed in the state of ERS. Over-expression of Nkx6.1 protected the INS-1-3 cells from glucolipotoxicity.
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Affiliation(s)
- Yanan Dong
- Department of Endocrinology, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China
| | - Shirui Li
- Department of Endocrinology, China-Japan Friendship Hospital, Beijing, China
| | - Wenhui Zhao
- Department of Endocrinology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Changping District, Beijing, China
| | - Yanlei Wang
- Department of Endocrinology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Changping District, Beijing, China
| | - Tingting Ge
- Department of Endocrinology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Changping District, Beijing, China
| | - Jianzhong Xiao
- Department of Endocrinology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University, Changping District, Beijing, China
| | - Yukun Li
- Department of Endocrinology, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China
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97
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Junjappa RP, Patil P, Bhattarai KR, Kim HR, Chae HJ. IRE1α Implications in Endoplasmic Reticulum Stress-Mediated Development and Pathogenesis of Autoimmune Diseases. Front Immunol 2018; 9:1289. [PMID: 29928282 PMCID: PMC5997832 DOI: 10.3389/fimmu.2018.01289] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 05/22/2018] [Indexed: 12/15/2022] Open
Abstract
Inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α) is the most prominent and evolutionarily conserved endoplasmic reticulum (ER) membrane protein. This transduces the signal of misfolded protein accumulation in the ER, named as ER stress, to the nucleus as “unfolded protein response (UPR).” The ER stress-mediated IRE1α signaling pathway arbitrates the yin and yang of cell life. IRE1α has been implicated in several physiological as well as pathological conditions, including immune disorders. Autoimmune diseases are caused by abnormal immune responses that develop due to genetic mutations and several environmental factors, including infections and chemicals. These factors dysregulate the cell immune reactions, such as cytokine secretion, antigen presentation, and autoantigen generation. However, the mechanisms involved, in which these factors induce the onset of autoimmune diseases, are remaining unknown. Considering that these environmental factors also induce the UPR, which is expected to have significant role in secretory cells and immune cells. The role of the major UPR molecule, IRE1α, in causing immune responses is well identified, but its role in inducing autoimmunity and the pathogenesis of autoimmune diseases has not been clearly elucidated. Hence, a better understanding of the role of IRE1α and its regulatory mechanisms in causing autoimmune diseases could help to identify and develop the appropriate therapeutic strategies. In this review, we mainly center the discussion on the molecular mechanisms of IRE1α in the pathophysiology of autoimmune diseases.
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Affiliation(s)
- Raghu Patil Junjappa
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Chonbuk National University, Jeonju, South Korea
| | - Prakash Patil
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Chonbuk National University, Jeonju, South Korea
| | - Kashi Raj Bhattarai
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Chonbuk National University, Jeonju, South Korea
| | - Hyung-Ryong Kim
- Graduate School, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, South Korea
| | - Han-Jung Chae
- Department of Pharmacology, School of Medicine, Institute of New Drug Development, Chonbuk National University, Jeonju, South Korea
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98
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Arunagiri A, Haataja L, Cunningham CN, Shrestha N, Tsai B, Qi L, Liu M, Arvan P. Misfolded proinsulin in the endoplasmic reticulum during development of beta cell failure in diabetes. Ann N Y Acad Sci 2018; 1418:5-19. [PMID: 29377149 DOI: 10.1111/nyas.13531] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 09/14/2017] [Accepted: 09/25/2017] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is broadly distributed throughout the cytoplasm of pancreatic beta cells, and this is where all proinsulin is initially made. Healthy beta cells can synthesize 6000 proinsulin molecules per second. Ordinarily, nascent proinsulin entering the ER rapidly folds via the formation of three evolutionarily conserved disulfide bonds (B7-A7, B19-A20, and A6-A11). A modest amount of proinsulin misfolding, including both intramolecular disulfide mispairing and intermolecular disulfide-linked protein complexes, is a natural by-product of proinsulin biosynthesis, as is the case for many proteins. The steady-state level of misfolded proinsulin-a potential ER stressor-is linked to (1) production rate, (2) ER environment, (3) presence or absence of naturally occurring (mutational) defects in proinsulin, and (4) clearance of misfolded proinsulin molecules. Accumulation of misfolded proinsulin beyond a certain threshold begins to interfere with the normal intracellular transport of bystander proinsulin, leading to diminished insulin production and hyperglycemia, as well as exacerbating ER stress. This is most obvious in mutant INS gene-induced Diabetes of Youth (MIDY; an autosomal dominant disease) but also likely to occur in type 2 diabetes owing to dysregulation in proinsulin synthesis, ER folding environment, or clearance.
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Affiliation(s)
- Anoop Arunagiri
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Leena Haataja
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
| | - Corey N Cunningham
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, Michigan
| | - Neha Shrestha
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Billy Tsai
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan
| | - Ling Qi
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Ming Liu
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan.,Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Peter Arvan
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, Michigan
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99
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Berry C, Lal M, Binukumar BK. Crosstalk Between the Unfolded Protein Response, MicroRNAs, and Insulin Signaling Pathways: In Search of Biomarkers for the Diagnosis and Treatment of Type 2 Diabetes. Front Endocrinol (Lausanne) 2018; 9:210. [PMID: 29770126 PMCID: PMC5940743 DOI: 10.3389/fendo.2018.00210] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 04/16/2018] [Indexed: 12/14/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) is a metabolic disorder that is characterized by functional defects in glucose metabolism and insulin secretion. Its complex etiology and multifaceted nature have made it difficult to design effective therapies for early diagnosis and treatment. Several lines of evidence indicate that aberrant activation of the unfolded protein response (UPR) in response to endoplasmic reticulum (ER) stress impairs the β cell's ability to respond to glucose and promotes apoptosis. Elucidating the molecular mechanisms that govern β cell dysfunction and cell death can help investigators design therapies to halt or prevent the development of T2DM. Early diagnosis of T2DM, however, warrants additionally the identification of potential biomarkers. MicroRNAs (miRNAs) are key regulators of transcriptional processes that modulate various features of insulin signaling, such as insulin sensitivity, glucose tolerance, and insulin secretion. A deeper understanding of how changes in patterns of expression of miRNAs correlate with altered glucose metabolism can enable investigators to develop methods for the early diagnosis and treatment of T2DM. The first part of this review examines how altered expression of specific UPR pathway proteins disrupts ER function and causes β cell dysfunction, while the second part discusses the potential role of miRNAs in the diagnostic and treatment of T2DM.
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Affiliation(s)
- Chinar Berry
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Megha Lal
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Delhi, India
| | - B. K. Binukumar
- CSIR-Institute of Genomics and Integrative Biology, Delhi, India
- Academy of Scientific and Innovative Research (AcSIR), Delhi, India
- *Correspondence: B. K. Binukumar, ,
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100
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Arai K, Ueno H, Asano Y, Chakrabarty G, Shimodaira S, Mugesh G, Iwaoka M. Protein Folding in the Presence of Water-Soluble Cyclic Diselenides with Novel Oxidoreductase and Isomerase Activities. Chembiochem 2017; 19:207-211. [PMID: 29197144 DOI: 10.1002/cbic.201700624] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Indexed: 01/29/2023]
Abstract
The protein disulfide isomerase (PDI) family, found in the endoplasmic reticulum (ER) of the eukaryotic cell, catalyzes the formation and cleavage of disulfide bonds and thereby helps in protein folding. A decrease in PDI activity under ER stress conditions leads to protein misfolding, which is responsible for the progression of various human diseases, such as Alzheimer's, Parkinson's, diabetes mellitus, and atherosclerosis. Here we report that water-soluble cyclic diselenides mimic the multifunctional activity of the PDI family by facilitating oxidative folding, disulfide formation/reduction, and repair of the scrambled disulfide bonds in misfolded proteins.
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Affiliation(s)
- Kenta Arai
- Department of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa, 259-1292, Japan
| | - Haruhito Ueno
- Department of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa, 259-1292, Japan
| | - Yuki Asano
- Department of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa, 259-1292, Japan
| | - Gaurango Chakrabarty
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Shingo Shimodaira
- Department of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa, 259-1292, Japan
| | - Govindasamy Mugesh
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Michio Iwaoka
- Department of Chemistry, School of Science, Tokai University, Kitakaname, Hiratsuka-shi, Kanagawa, 259-1292, Japan
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