1
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Sviben S, Polino AJ, Melena IL, Hughes JW. Immuno-scanning electron microscopy of islet primary cilia. J Cell Sci 2024; 137:jcs262038. [PMID: 38804679 PMCID: PMC11166453 DOI: 10.1242/jcs.262038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 04/19/2024] [Indexed: 05/29/2024] Open
Abstract
The definitive demonstration of protein localization on primary cilia has been a challenge for cilia biologists. Primary cilia are solitary thread-like projections that have a specialized protein composition, but as the ciliary structure overlays the cell membrane and other cell parts, the identity of ciliary proteins are difficult to ascertain by conventional imaging approaches like immunofluorescence microscopy. Surface scanning electron microscopy combined with immunolabeling (immuno-SEM) bypasses some of these indeterminacies by unambiguously showing protein expression in the context of the three-dimensional ultrastructure of the cilium. Here, we apply immuno-SEM to specifically identify proteins on the primary cilia of mouse and human pancreatic islets, including post-translationally modified tubulin, intraflagellar transport (IFT)88, the small GTPase Arl13b, as well as subunits of axonemal dynein. Key parameters in sample preparation, immunolabeling and imaging acquisition are discussed to facilitate similar studies by others in the cilia research community.
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Affiliation(s)
- Sanja Sviben
- Washington University Center for Cellular Imaging, Washington University School of Medicine, 660 South Euclid Ave, Saint Louis, MO 63110, USA
| | - Alexander J. Polino
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Ave, Saint Louis, MO 63110, USA
| | - Isabella L. Melena
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, Saint Louis, MO 63110, USA
| | - Jing W. Hughes
- Department of Cell Biology and Physiology, Washington University School of Medicine, 660 South Euclid Ave, Saint Louis, MO 63110, USA
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, Saint Louis, MO 63110, USA
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2
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Hilgendorf KI, Myers BR, Reiter JF. Emerging mechanistic understanding of cilia function in cellular signalling. Nat Rev Mol Cell Biol 2024; 25:555-573. [PMID: 38366037 PMCID: PMC11199107 DOI: 10.1038/s41580-023-00698-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2023] [Indexed: 02/18/2024]
Abstract
Primary cilia are solitary, immotile sensory organelles present on most cells in the body that participate broadly in human health, physiology and disease. Cilia generate a unique environment for signal transduction with tight control of protein, lipid and second messenger concentrations within a relatively small compartment, enabling reception, transmission and integration of biological information. In this Review, we discuss how cilia function as signalling hubs in cell-cell communication using three signalling pathways as examples: ciliary G-protein-coupled receptors (GPCRs), the Hedgehog (Hh) pathway and polycystin ion channels. We review how defects in these ciliary signalling pathways lead to a heterogeneous group of conditions known as 'ciliopathies', including metabolic syndromes, birth defects and polycystic kidney disease. Emerging understanding of these pathways' transduction mechanisms reveals common themes between these cilia-based signalling pathways that may apply to other pathways as well. These mechanistic insights reveal how cilia orchestrate normal and pathophysiological signalling outputs broadly throughout human biology.
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Affiliation(s)
- Keren I Hilgendorf
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.
| | - Benjamin R Myers
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT, USA.
- Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA.
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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3
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Aziz-Zanjani MO, Turn RE, Xu LA, Jackson PK. Synchronized Temporal-spatial Analysis via Microscopy and Phoshoproteomics (STAMP) of Quiescence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.24.600542. [PMID: 38979361 PMCID: PMC11230294 DOI: 10.1101/2024.06.24.600542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Tightly coordinated cell cycle regulation is essential for homeostasis. G 0 , or quiescence, is especially crucial for cells to respond to extracellular stimuli. Little is known about the mechanisms that establish the G 0 program, though the primary cilium (a key signaling hub formed only in G 0 ) is the most widely recognized marker. The study of ciliogenesis is challenging due to its small size, relative to the cell body. To address this gap in our understanding, we developed STAMP (Spatio-Temporal Analysis via Microscopy and Proteomics) to temporally map the changes in cellular landscape occurring in G 0 and ciliogenesis. Using synchronized RPE cells, we used fixed and live cell imaging combined with phosphoproteomics to uncover new signals and order them in these processes, which also allows further, more targeted, analyses (e.g., using genetic and pharmacological perturbations). We propose that STAMP is broadly applicable for studying temporal-spatial signaling processes and the underlying mechanisms in various biological contexts and cell types.
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4
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Zhou P, Hu M, Li Q, Yang G. Both intrinsic and microenvironmental factors contribute to the regulation of stem cell quiescence. J Cell Physiol 2024. [PMID: 38860372 DOI: 10.1002/jcp.31325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 05/06/2024] [Accepted: 05/13/2024] [Indexed: 06/12/2024]
Abstract
Precise regulation of stem cell quiescence is essential for tissue development and homeostasis. Therefore, its aberrant regulation is intimately correlated with various human diseases. However, the detailed mechanisms of stem cell quiescence and its specific role in the pathogenesis of various diseases remain to be determined. Recent studies have revealed that the intrinsic and microenvironmental factors are the potential candidates responsible for the orderly switch between the dormant and activated states of stem cells. In addition, defects in signaling pathways related to internal and external factors of stem cells might contribute to the initiation and development of diseases by altering the dormancy of stem cells. In this review, we focus on the mechanisms underlying stem cell quiescence, especially the involvement of intrinsic and microenvironmental factors. In addition, we discuss the relationship between the anomalies of stem cell quiescence and related diseases, hopefully providing therapeutic insights for developing novel treatments.
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Affiliation(s)
- Ping Zhou
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Mingzheng Hu
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Qingchao Li
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Guiwen Yang
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan, China
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5
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Adamson SE, Hughes JW. Paracrine Signaling by Pancreatic Islet Cilia. CURRENT OPINION IN ENDOCRINE AND METABOLIC RESEARCH 2024; 35:100505. [PMID: 38524256 PMCID: PMC10956557 DOI: 10.1016/j.coemr.2024.100505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
The primary cilium is a sensory and signaling organelle present on most pancreatic islet endocrine cells, where it receives and interprets a wide range of intra-islet chemical cues including hormones, peptides, and neurotransmitters. The ciliary membrane possesses a molecular composition distinct from the plasma membrane, with enrichment of signaling mediators including G protein-coupled receptors (GPCRs), tyrosine kinase family receptors, membrane transporters and others. When activated, these membrane proteins interact with ion channels and adenylyl cyclases to trigger local Ca2+ and cAMP activity and transmit signals to the cell body. Here we review evidence supporting the emerging model in which primary cilia on pancreatic islet cells play a central role in the intra-islet communication network and discuss how changes in cilia-mediated paracrine function in islet cells might lead to diabetes.
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Affiliation(s)
- Samantha E Adamson
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, St. Louis, MO, USA
| | - Jing W Hughes
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, St. Louis, MO, USA
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Jevon D, Cottle L, Hallahan N, Harwood R, Samra JS, Gill AJ, Loudovaris T, Thomas HE, Thorn P. Capillary contact points determine beta cell polarity, control secretion and are disrupted in the db/db mouse model of diabetes. Diabetologia 2024:10.1007/s00125-024-06180-x. [PMID: 38814445 DOI: 10.1007/s00125-024-06180-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 03/26/2024] [Indexed: 05/31/2024]
Abstract
AIMS/HYPOTHESIS Almost all beta cells contact one capillary and insulin granule fusion is targeted to this region. However, there are reports of beta cells contacting more than one capillary. We therefore set out to determine the proportion of beta cells with multiple contacts and the impact of this on cell structure and function. METHODS We used pancreatic slices in mice and humans to better maintain cell and islet structure than in isolated islets. Cell structure was assayed using immunofluorescence and 3D confocal microscopy. Live-cell two-photon microscopy was used to map granule fusion events in response to glucose stimulation. RESULTS We found that 36% and 22% of beta cells in islets from mice and humans, respectively, have separate contact with two capillaries. These contacts establish a distinct form of cell polarity with multiple basal regions. Both capillary contact points are enriched in presynaptic scaffold proteins, and both are a target for insulin granule fusion. Cells with two capillary contact points have a greater capillary contact area and secrete more, with analysis showing that, independent of the number of contact points, increased contact area is correlated with increased granule fusion. Using db/db mice as a model for type 2 diabetes, we observed changes in islet capillary organisation that significantly reduced total islet capillary surface area, and reduced area of capillary contact in single beta cells. CONCLUSIONS/INTERPRETATION Beta cells that contact two capillaries are a significant subpopulation of beta cells within the islet. They have a distinct form of cell polarity and both contact points are specialised for secretion. The larger capillary contact area of cells with two contact points is correlated with increased secretion. In the db/db mouse, changes in capillary structure impact beta cell capillary contact, implying that this is a new factor contributing to disease progression.
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Affiliation(s)
- Dillon Jevon
- Charles Perkins Centre, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Louise Cottle
- Charles Perkins Centre, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Nicole Hallahan
- Charles Perkins Centre, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia
| | - Richard Harwood
- Charles Perkins Centre, Sydney Microscopy and Microanalysis, University of Sydney, Camperdown, NSW, Australia
| | - Jaswinder S Samra
- The University of Sydney Northern Clinical School, Sydney, NSW, Australia
- Upper Gastrointestinal Surgical Unit, Royal North Shore Hospital, St Leonards, NSW, Australia
| | - Anthony J Gill
- The University of Sydney Northern Clinical School, Sydney, NSW, Australia
- Department of Anatomical Pathology, Royal North Shore Hospital, St Leonards, NSW, Australia
- Cancer Diagnosis and Pathology Research Group, Kolling Institute of Medical Research, St Leonards, NSW, Australia
| | | | - Helen E Thomas
- St Vincent's Institute, Fitzroy, VIC, Australia
- Department of Medicine, St Vincent's Hospital, University of Melbourne, Fitzroy, VIC, Australia
| | - Peter Thorn
- Charles Perkins Centre, School of Medical Sciences, University of Sydney, Camperdown, NSW, Australia.
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7
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Idevall-Hagren O, Incedal Nilsson C, Sanchez G. Keeping pace: the primary cilium as the conducting baton of the islet. Diabetologia 2024; 67:773-782. [PMID: 38353726 PMCID: PMC10955035 DOI: 10.1007/s00125-024-06096-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/03/2024] [Indexed: 03/21/2024]
Abstract
Primary cilia are rod-like sensory organelles that protrude from the surface of most mammalian cells, including the cells of the islet, and mounting evidence supports important roles of these structures in the regulation of beta cell function and insulin secretion. The sensory abilities of the cilium arise from local receptor activation that is coupled to intrinsic signal transduction, and ciliary signals can propagate into the cell and influence cell function. Here, we review recent advances and studies that provide insights into intra-islet cues that trigger primary cilia signalling; how second messenger signals are generated and propagated within cilia; and how ciliary signalling affects beta cell function. We also discuss the potential involvement of primary cilia and ciliary signalling in the development and progression of type 2 diabetes, identify gaps in our current understanding of islet cell cilia function and provide suggestions on how to further our understanding of this intriguing structure.
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Affiliation(s)
| | | | - Gonzalo Sanchez
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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8
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Sviben S, Polino AJ, Melena I, Hughes JW. Immuno-Scanning Electron Microscopy of Islet Primary Cilia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.16.580695. [PMID: 38405740 PMCID: PMC10888824 DOI: 10.1101/2024.02.16.580695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The definitive demonstration of protein localization on primary cilia has been a challenge for cilia biologists. Primary cilia are solitary thread-like projections that contain specialized protein composition, but as the ciliary structure overlays the cell membrane and other cell parts, the identity of ciliary proteins are difficult to ascertain by conventional imaging approaches like immunofluorescence microscopy. Surface scanning electron microscopy combined with immuno-labeling (immuno-SEM) bypasses some of these indeterminacies by unambiguously showing protein expression in the context of the 3D ultrastructure of the cilium. Here we apply immuno-SEM to specifically identify proteins on the primary cilia of mouse and human pancreatic islets, including post-translationally modified tubulin, intraflagellar transport (IFT) 88, the small GTPase Arl13b, as well as subunits of axonemal dynein. Key parameters in sample preparation, immuno-labeling, and imaging acquisition are discussed to facilitate similar studies by others in the cilia research community.
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9
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Bevacqua RJ, Zhao W, Merheb E, Kim SH, Marson A, Gloyn AL, Kim SK. Multiplexed CRISPR gene editing in primary human islet cells with Cas9 ribonucleoprotein. iScience 2024; 27:108693. [PMID: 38205242 PMCID: PMC10777115 DOI: 10.1016/j.isci.2023.108693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 10/27/2023] [Accepted: 12/05/2023] [Indexed: 01/12/2024] Open
Abstract
Successful genome editing in primary human islets could reveal features of the genetic regulatory landscape underlying β cell function and diabetes risk. Here, we describe a CRISPR-based strategy to interrogate functions of predicted regulatory DNA elements using electroporation of a complex of Cas9 ribonucleoprotein (Cas9 RNP) and guide RNAs into primary human islet cells. We successfully targeted coding regions including the PDX1 exon 1, and non-coding DNA linked to diabetes susceptibility. CRISPR-Cas9 RNP approaches revealed genetic targets of regulation by DNA elements containing candidate diabetes risk SNPs, including an in vivo enhancer of the MPHOSPH9 gene. CRISPR-Cas9 RNP multiplexed targeting of two cis-regulatory elements linked to diabetes risk in PCSK1, which encodes an endoprotease crucial for Insulin processing, also demonstrated efficient simultaneous editing of PCSK1 regulatory elements, resulting in impaired β cell PCSK1 regulation and Insulin secretion. Multiplex CRISPR-Cas9 RNP provides powerful approaches to investigate and elucidate human islet cell gene regulation in health and diabetes.
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Affiliation(s)
- Romina J Bevacqua
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Diabetes, Obesity and Metabolism Institute (DOMI), Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Weichen Zhao
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Emilio Merheb
- Diabetes, Obesity and Metabolism Institute (DOMI), Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Seung Hyun Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alexander Marson
- Gladstone-UCSF Institute of Genomic Immunology and Northern California JDRF Center of Excellence, University of California at San Francisco, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Anna L Gloyn
- Department of Pediatrics (Endocrinology) and of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Seung K Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
- Departments of Medicine and of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA 94305, USA
- Northern California JDRF Center of Excellence, Stanford University School of Medicine, Stanford, CA 94305, USA
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10
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Adamson SE, Li ZA, Hughes JW. Beta cell primary cilia mediate somatostatin responsiveness via SSTR3. Islets 2023; 15:2252855. [PMID: 37660302 PMCID: PMC10478741 DOI: 10.1080/19382014.2023.2252855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 08/23/2023] [Accepted: 08/24/2023] [Indexed: 09/05/2023] Open
Abstract
Somatostatin is a paracrine modulator of insulin secretion and beta cell function with pleotropic effects on glucose homeostasis. The mechanism of somatostatin-mediated communication between delta and beta cells is not well-understood, which we address in this study via the ciliary somatostatin receptor 3 (SSTR3). Primary cilia are membrane organelles that act as signaling hubs in islets by virtue of their subcellular location and enrichment in signaling proteins such as G-protein coupled receptors (GPCRs). We show that SSTR3, a ciliary GPCR, mediates somatostatin suppression of insulin secretion in mouse islets. Quantitative analysis of calcium flux using a mouse model of genetically encoded beta cell-specific GCaMP6f calcium reporter shows that somatostatin signaling alters beta cell calcium flux after physiologic glucose stimulation, an effect that depends on endogenous SSTR3 expression and the presence of intact primary cilia on beta cells. Comparative in vitro studies using SSTR isoform antagonists demonstrate a role for SSTR3 in mediating somatostatin regulation of insulin secretion in mouse islets. Our findings support a model in which ciliary SSTR3 mediates a distinct pathway of delta-to-beta cell regulatory crosstalk and may serve as a target for paracrine modulation.
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Affiliation(s)
- Samantha E. Adamson
- Department of Medicine, Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, St. Louis, USA
| | - Zipeng A. Li
- Department of Medicine, Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, St. Louis, USA
| | - Jing W. Hughes
- Department of Medicine, Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine, St. Louis, USA
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11
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Bevacqua RJ, Zhao W, Merheb E, Kim SH, Marson A, Gloyn AL, Kim SK. Multiplexed CRISPR gene editing in primary human islet cells with Cas9 ribonucleoprotein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.16.558090. [PMID: 37745551 PMCID: PMC10516051 DOI: 10.1101/2023.09.16.558090] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Successful genome editing in primary human islets could reveal features of the genetic regulatory landscape underlying β cell function and diabetes risk. Here, we describe a CRISPR-based strategy to interrogate functions of predicted regulatory DNA elements using electroporation of a complex of Cas9 ribonucleoprotein (Cas9 RNP) and guide RNAs into primary human islet cells. We successfully targeted coding regions including the PDX1 exon 1, and non-coding DNA linked to diabetes susceptibility. CRISPR/Cas9 RNP approaches revealed genetic targets of regulation by DNA elements containing candidate diabetes risk SNPs, including an in vivo enhancer of the MPHOSPH9 gene. CRISPR/Cas9 RNP multiplexed targeting of two cis-regulatory elements linked to diabetes risk in PCSK1, which encodes an endoprotease crucial for insulin processing, also demonstrated efficient simultaneous editing of PCSK1 regulatory elements, resulting in impaired β cell PCSK1 regulation and insulin secretion. Multiplex CRISPR/Cas9 RNP provides powerful approaches to investigate and elucidate human islet cell gene regulation in health and diabetes.
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Affiliation(s)
- Romina J. Bevacqua
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Diabetes, Obesity and Metabolism Institute (DOMI), Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
- Mount Sinai Regenerative Biology and Stem Cell Institute, New York, NY, United States
| | - Weichen Zhao
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Emilio Merheb
- Diabetes, Obesity and Metabolism Institute (DOMI), Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Seung Hyun Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Alexander Marson
- Gladstone-UCSF Institute of Genomic Immunology and Northern California JDRF Center of Excellence, University of California at San Francisco, CA, 94158, USA
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
- Diabetes Center, University of California, San Francisco, San Francisco, CA 94143, USA
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Anna L. Gloyn
- Department of Pediatrics (Endocrinology) and of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Departments of Medicine and of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Seung K. Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Departments of Medicine and of Pediatrics, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA, 94305, USA
- Northern California JDRF Center of Excellence, Stanford University School of Medicine, Stanford, CA, 94305, USA
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12
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Terry TT, Gigante ED, Alexandre CM, Brewer KM, Engle SE, Yue X, Berbari NF, Vaisse C, Caspary T. Ciliary ARL13B prevents obesity in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.02.551695. [PMID: 37577625 PMCID: PMC10418222 DOI: 10.1101/2023.08.02.551695] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Cilia are near ubiquitous small, cellular appendages critical for cell-to-cell communication. As such, they are involved in diverse developmental and homeostatic processes, including energy homeostasis. ARL13B is a regulatory GTPase highly enriched in cilia. Mice expressing an engineered ARL13B variant, ARL13BV358A which retains normal biochemical activity, display no detectable ciliary ARL13B. Surprisingly, these mice become obese. Here, we measured body weight, food intake, and blood glucose levels to reveal these mice display hyperphagia and metabolic defects. We showed that ARL13B normally localizes to cilia of neurons in specific brain regions and pancreatic cells but is excluded from these cilia in the Arl13bV358A/V358A model. In addition to its GTPase function, ARL13B acts as a guanine nucleotide exchange factor (GEF) for ARL3. To test whether ARL13B's GEF activity is required to regulate body weight, we analyzed the body weight of mice expressing ARL13BR79Q, a variant that lacks ARL13B GEF activity for ARL3. We found no difference in body weight. Taken together, our results show that ARL13B functions within cilia to control body weight and that this function does not depend on its role as a GEF for ARL3. Controlling the subcellular localization of ARL13B in the engineered mouse model, ARL13BV358A, enables us to define the cilia-specific role of ARL13B in regulating energy homeostasis.
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Affiliation(s)
- Tiffany T. Terry
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Suite 301, Atlanta, GA 30322, USA
| | - Eduardo D. Gigante
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Suite 301, Atlanta, GA 30322, USA
- Graduate Program in Neuroscience, Laney Graduate School, Emory University, 201 Dowman Dr., Atlanta, GA 30307, USA
- Present address: Department of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Coralie M. Alexandre
- Diabetes Center and Department of Medicine, University of California San Francisco, San Francisco, California 94143
| | - Kathryn M. Brewer
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202
| | - Staci E. Engle
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202
| | - Xinyu Yue
- Diabetes Center and Department of Medicine, University of California San Francisco, San Francisco, California 94143
| | - Nicolas F. Berbari
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Indiana 46202
| | - Christian Vaisse
- Diabetes Center and Department of Medicine, University of California San Francisco, San Francisco, California 94143
| | - Tamara Caspary
- Department of Human Genetics, Emory University School of Medicine, 615 Michael Street, Suite 301, Atlanta, GA 30322, USA
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13
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Zhang Y, Tawiah GK, Wu X, Zhang Y, Wang X, Wei X, Qiao X, Zhang Q. Primary cilium-mediated mechanotransduction in cartilage chondrocytes. Exp Biol Med (Maywood) 2023; 248:1279-1287. [PMID: 37897221 PMCID: PMC10625344 DOI: 10.1177/15353702231199079] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2023] Open
Abstract
Osteoarthritis (OA) is one of the most prevalent joint disorders associated with the degradation of articular cartilage and an abnormal mechanical microenvironment. Mechanical stimuli, including compression, shear stress, stretching strain, osmotic challenge, and the physical properties of the matrix microenvironment, play pivotal roles in the tissue homeostasis of articular cartilage. The primary cilium, as a mechanosensory and chemosensory organelle, is important for detecting and transmitting both mechanical and biochemical signals in chondrocytes within the matrix microenvironment. Growing evidence indicates that primary cilia are critical for chondrocytes signaling transduction and the matrix homeostasis of articular cartilage. Furthermore, the ability of primary cilium to regulate cellular signaling is dynamic and dependent on the cellular matrix microenvironment. In the current review, we aim to elucidate the key mechanisms by which primary cilia mediate chondrocytes sensing and responding to the matrix mechanical microenvironment. This might have potential therapeutic applications in injuries and OA-associated degeneration of articular cartilage.
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Affiliation(s)
- Yang Zhang
- Department of Histology and Embryology, Shanxi Medical University, Jinzhong 030604, Shanxi, China
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
| | - Godfred K Tawiah
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
| | - Xiaoan Wu
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Yanjun Zhang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
| | - Xiaohu Wang
- Department of Orthopaedics, The Second Hospital of Shanxi Medical University, Shanxi Key Laboratory of Bone and Soft Tissue Injury Repair, Shanxi Medical University, Taiyuan 030001, Shanxi, China
| | - Xiaochun Wei
- Department of Orthopaedics, The Second Hospital of Shanxi Medical University, Shanxi Key Laboratory of Bone and Soft Tissue Injury Repair, Shanxi Medical University, Taiyuan 030001, Shanxi, China
| | - Xiaohong Qiao
- Department of Histology and Embryology, Shanxi Medical University, Jinzhong 030604, Shanxi, China
- Department of Orthopaedics, Lvliang Hospital Affiliated to Shanxi Medical University, Lvliang 033099, Shanxi, China
| | - Quanyou Zhang
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China
- Department of Orthopaedics, The Second Hospital of Shanxi Medical University, Shanxi Key Laboratory of Bone and Soft Tissue Injury Repair, Shanxi Medical University, Taiyuan 030001, Shanxi, China
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14
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Monfared RV, Abdelkarim S, Derdeyn P, Chen K, Wu H, Leong K, Chang T, Lee J, Versales S, Nauli S, Beier K, Baldi P, Alachkar A. Spatiotemporal Mapping of Brain Cilia Reveals Region-Specific Oscillation of Length and Orientation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.28.546950. [PMID: 37425809 PMCID: PMC10326993 DOI: 10.1101/2023.06.28.546950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
In this study, we conducted high-throughput spatiotemporal analysis of primary cilia length and orientation across 22 mouse brain regions. We developed automated image analysis algorithms, which enabled us to examine over 10 million individual cilia, generating the largest spatiotemporal atlas of cilia. We found that cilia length and orientation display substantial variations across different brain regions and exhibit fluctuations over a 24-hour period, with region-specific peaks during light-dark phases. Our analysis revealed unique orientation patterns of cilia at 45 degree intervals, suggesting that cilia orientation within the brain is not random but follows specific patterns. Using BioCycle, we identified circadian rhythms of cilia length in five brain regions: nucleus accumbens core, somatosensory cortex, and three hypothalamic nuclei. Our findings present novel insights into the complex relationship between cilia dynamics, circadian rhythms, and brain function, highlighting cilia crucial role in the brain's response to environmental changes and regulation of time-dependent physiological processes.
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15
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Lee EY, Hughes JW. Rediscovering Primary Cilia in Pancreatic Islets. Diabetes Metab J 2023; 47:454-469. [PMID: 37105527 PMCID: PMC10404530 DOI: 10.4093/dmj.2022.0442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/15/2023] [Indexed: 04/29/2023] Open
Abstract
Primary cilia are microtubule-based sensory and signaling organelles on the surfaces of most eukaryotic cells. Despite their early description by microscopy studies, islet cilia had not been examined in the functional context until recent decades. In pancreatic islets as in other tissues, primary cilia facilitate crucial developmental and signaling pathways in response to extracellular stimuli. Many human developmental and genetic disorders are associated with ciliary dysfunction, some manifesting as obesity and diabetes. Understanding the basis for metabolic diseases in human ciliopathies has been aided by close examination of cilia action in pancreatic islets at cellular and molecular levels. In this article, we review the evidence for ciliary expression on islet cells, known roles of cilia in pancreas development and islet hormone secretion, and summarize metabolic manifestations of human ciliopathy syndromes. We discuss emerging data on primary cilia regulation of islet cell signaling and the structural basis of cilia-mediated cell crosstalk, and offer our interpretation on the role of cilia in glucose homeostasis and human diseases.
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Affiliation(s)
- Eun Young Lee
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Jing W. Hughes
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
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16
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Polino AJ, Sviben S, Melena I, Piston DW, Hughes JW. Scanning electron microscopy of human islet cilia. Proc Natl Acad Sci U S A 2023; 120:e2302624120. [PMID: 37205712 PMCID: PMC10235940 DOI: 10.1073/pnas.2302624120] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 04/12/2023] [Indexed: 05/21/2023] Open
Abstract
Human islet primary cilia are vital glucose-regulating organelles whose structure remains uncharacterized. Scanning electron microscopy (SEM) is a useful technique for studying the surface morphology of membrane projections like cilia, but conventional sample preparation does not reveal the submembrane axonemal structure, which holds key implications for ciliary function. To overcome this challenge, we combined SEM with membrane-extraction techniques to examine primary cilia in native human islets. Our data show well-preserved cilia subdomains which demonstrate both expected and unexpected ultrastructural motifs. Morphometric features were quantified when possible, including axonemal length and diameter, microtubule conformations, and chirality. We further describe a ciliary ring, a structure that may be a specialization in human islets. Key findings are correlated with fluorescence microscopy and interpreted in the context of cilia function as a cellular sensor and communications locus in pancreatic islets.
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Affiliation(s)
- Alexander J. Polino
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO63110
| | - Sanja Sviben
- Washington University Center for Cellular Imaging, Washington University School of Medicine, Saint Louis, MO63110
| | - Isabella Melena
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO63110
| | - David W. Piston
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO63110
| | - Jing W. Hughes
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO63110
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO63110
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17
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Fadl SM, Kafaji M, Abdalla H, Dabbour MA, Al-Shamrani A. Primary Ciliary Dyskinesia and Type 1 Diabetes: True Association or Circumstantial? Cureus 2023; 15:e39344. [PMID: 37351244 PMCID: PMC10284442 DOI: 10.7759/cureus.39344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2023] [Indexed: 06/24/2023] Open
Abstract
Primary ciliary dyskinesia (PCD) is a rare autosomal recessive inherited heterogeneous respiratory disorder. The diagnosis of PCD is challenging and necessitates a multi-test diagnostic approach because there are no gold standard diagnostic tests available to confirm PCD. However, rapid advancement in understanding the molecular genetic basis of PCD has greatly improved PCD diagnosis. Studies have reported that PCD may increase the risk of rheumatoid arthritis, congenital heart disease, severe esophageal diseases, and others. Therefore, the present study aimed to assess the risk of type 1 diabetes mellitus (T1DM) in a genetically confirmed PCD patient. In this case study, an 11-year-old girl with autosinopulmonary infections and her younger brother were diagnosed with PCD. The patient's DNA was extracted for next-generation exome sequencing. Our analysis of the exome sequencing data revealed the PCD-causing genetic variant p.Glu286del in the RSPH9 gene on chromosome 6p21.1. In addition, the biochemical findings at the time of patient's admission showed elevated glutamic acid decarboxylase antibodies, HbA1c, and ketone levels, with impaired glucose tolerance, which indicated the presence of T1DM. In conclusion, the clinical features, biochemical reports, and genetic testing confirmed PCD in this patient and the possible association between PCD and T1DM.
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Affiliation(s)
- Sarrah M Fadl
- Pediatric Pulmonology, Prince Sultan Military Medical City, Riyadh, SAU
| | - Mustafa Kafaji
- General Surgery, College of Medicine, Alfaisal University, Riyadh, SAU
| | - Hesham Abdalla
- General Surgery, College of Medicine, Alfaisal University, Riyadh, SAU
| | - Maryam A Dabbour
- Pediatric Pulmonology, Prince Sultan Military Medical City, Riyadh, SAU
| | - Abdullah Al-Shamrani
- Pediatric Pulmonology, Prince Sultan Military Medical City, Riyadh, SAU
- Medicine, Alfaisal University, Riyadh, SAU
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18
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Chabosseau P, Yong F, Delgadillo-Silva LF, Lee EY, Melhem R, Li S, Gandhi N, Wastin J, Noriega LL, Leclerc I, Ali Y, Hughes JW, Sladek R, Martinez-Sanchez A, Rutter GA. Molecular phenotyping of single pancreatic islet leader beta cells by "Flash-Seq". Life Sci 2023; 316:121436. [PMID: 36706832 DOI: 10.1016/j.lfs.2023.121436] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 01/11/2023] [Accepted: 01/20/2023] [Indexed: 01/26/2023]
Abstract
AIMS Spatially-organized increases in cytosolic Ca2+ within pancreatic beta cells in the pancreatic islet underlie the stimulation of insulin secretion by high glucose. Recent data have revealed the existence of subpopulations of beta cells including "leaders" which initiate Ca2+ waves. Whether leader cells possess unique molecular features, or localisation, is unknown. MAIN METHODS High speed confocal Ca2+ imaging was used to identify leader cells and connectivity analysis, running under MATLAB and Python, to identify highly connected "hub" cells. To explore transcriptomic differences between beta cell sub-groups, individual leaders or followers were labelled by photo-activation of the cryptic fluorescent protein PA-mCherry and subjected to single cell RNA sequencing ("Flash-Seq"). KEY FINDINGS Distinct Ca2+ wave types were identified in individual islets, with leader cells present in 73 % (28 of 38 islets imaged). Scale-free, power law-adherent behaviour was also observed in 29 % of islets, though "hub" cells in these islets did not overlap with leaders. Transcripts differentially expressed (295; padj < 0.05) between leader and follower cells included genes involved in cilium biogenesis and transcriptional regulation. Providing some support for these findings, ADCY6 immunoreactivity tended to be higher in leader than follower cells, whereas cilia number and length tended to be lower in the former. Finally, leader cells were located significantly closer to delta, but not alpha, cells in Euclidian space than were follower cells. SIGNIFICANCE The existence of both a discrete transcriptome and unique localisation implies a role for these features in defining the specialized function of leaders. These data also raise the possibility that localised signalling between delta and leader cells contributes to the initiation and propagation of islet Ca2+ waves.
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Affiliation(s)
- Pauline Chabosseau
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Fiona Yong
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom; Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore
| | - Luis F Delgadillo-Silva
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Eun Young Lee
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States; Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, South Korea
| | - Rana Melhem
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Shiying Li
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Nidhi Gandhi
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Jules Wastin
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Livia Lopez Noriega
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Isabelle Leclerc
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada
| | - Yusuf Ali
- Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore
| | - Jing W Hughes
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
| | - Robert Sladek
- Departments of Medicine and Human Genetics, McGill University and Genome Quebec Innovation Centre, Montreal, QC, Canada
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Guy A Rutter
- Centre de Recherche du CHUM, Faculté de Médicine, Université de Montréal, Montréal, QC, Canada; Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom; Lee Kong Chian Imperial Medical School, Nanyang Technological University, Singapore.
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19
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Polino AJ, Sviben S, Melena I, Piston DW, Hughes J. Scanning electron microscopy of human islet cilia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528685. [PMID: 36824775 PMCID: PMC9949088 DOI: 10.1101/2023.02.15.528685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Human islet primary cilia are vital glucose-regulating organelles whose structure remains uncharacterized. Scanning electron microscopy (SEM) is a useful technique for studying the surface morphology of membrane projections like primary cilia, but conventional sample preparation does not reveal the sub-membrane axonemal structure which holds key implications for cilia function. To overcome this challenge, we combined SEM with membrane-extraction techniques to examine cilia in native human islets. Our data show well-preserved cilia subdomains which demonstrate both expected and unexpected ultrastructural motifs. Morphometric features were quantified when possible, including axonemal length and diameter, microtubule conformations and chirality. We further describe a novel ciliary ring, a structure that may be a specialization in human islets. Key findings are correlated with fluorescence microscopy and interpreted in the context of cilia function as a cellular sensor and communications locus in pancreatic islets.
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20
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Sanchez GM, Incedal TC, Prada J, O'Callaghan P, Dyachok O, Echeverry S, Dumral Ö, Nguyen PM, Xie B, Barg S, Kreuger J, Dandekar T, Idevall-Hagren O. The β-cell primary cilium is an autonomous Ca2+ compartment for paracrine GABA signaling. J Cell Biol 2023; 222:213674. [PMID: 36350286 DOI: 10.1083/jcb.202108101] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 04/11/2022] [Accepted: 10/12/2022] [Indexed: 11/11/2022] Open
Abstract
The primary cilium is an organelle present in most adult mammalian cells that is considered as an antenna for sensing the local microenvironment. Here, we use intact mouse pancreatic islets of Langerhans to investigate signaling properties of the primary cilium in insulin-secreting β-cells. We find that GABAB1 receptors are strongly enriched at the base of the cilium, but are mobilized to more distal locations upon agonist binding. Using cilia-targeted Ca2+ indicators, we find that activation of GABAB1 receptors induces selective Ca2+ influx into primary cilia through a mechanism that requires voltage-dependent Ca2+ channel activation. Islet β-cells utilize cytosolic Ca2+ increases as the main trigger for insulin secretion, yet we find that increases in cytosolic Ca2+ fail to propagate into the cilium, and that this isolation is largely due to enhanced Ca2+ extrusion in the cilium. Our work reveals local GABA action on primary cilia that involves Ca2+ influx and depends on restricted Ca2+ diffusion between the cilium and cytosol.
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Affiliation(s)
| | | | - Juan Prada
- Department of Bioinformatics, University of Würzburg, Würzburg, Germany
| | - Paul O'Callaghan
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Oleg Dyachok
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | | | - Özge Dumral
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Phuoc My Nguyen
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Beichen Xie
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Sebastian Barg
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Johan Kreuger
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Thomas Dandekar
- Department of Bioinformatics, University of Würzburg, Würzburg, Germany
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21
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Icariin Treatment Rescues Diabetes Induced Bone Loss via Scavenging ROS and Activating Primary Cilia/Gli2/Osteocalcin Signaling Pathway. Cells 2022; 11:cells11244091. [PMID: 36552853 PMCID: PMC9777100 DOI: 10.3390/cells11244091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 12/10/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Diabetes-associated bone complications lead to fragile bone mechanical strength and osteoporosis, aggravating the disease burden of patients. Advanced evidence shows that chronic hyperglycemia and metabolic intermediates, such as inflammatory factor, reactive oxygen species (ROS), and advanced glycation end products (AGEs), are regarded as dominant hazardous factors of bone complications, whereas the pathophysiological mechanisms are complex and controversial. By establishing a diabetic Sprague-Dawley (SD) rat model and diabetic bone loss cell model in vitro, we confirmed that diabetes impaired primary cilia and led to bone loss, while adding Icariin (ICA) could relieve the inhibitions. Mechanistically, ICA could scavenge ROS to maintain the mitochondrial and primary cilia homeostasis of osteoblasts. Intact primary cilia acted as anchoring and modifying sites of Gli2, thereby activating the primary cilia/Gli2/osteocalcin signaling pathway to promote osteoblast differentiation. All results suggest that ICA has potential as a therapeutic drug targeting bone loss induced by diabetes.
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22
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Melena I, Hughes JW. Islet cilia and glucose homeostasis. Front Cell Dev Biol 2022; 10:1082193. [PMID: 36531945 PMCID: PMC9751591 DOI: 10.3389/fcell.2022.1082193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 11/22/2022] [Indexed: 09/05/2023] Open
Abstract
Diabetes is a growing pandemic affecting over ten percent of the U.S. population. Individuals with all types of diabetes exhibit glucose dysregulation due to altered function and coordination of pancreatic islets. Within the critical intercellular space in pancreatic islets, the primary cilium emerges as an important physical structure mediating cell-cell crosstalk and signal transduction. Many events leading to hormone secretion, including GPCR and second-messenger signaling, are spatiotemporally regulated at the level of the cilium. In this review, we summarize current knowledge of cilia action in islet hormone regulation and glucose homeostasis, focusing on newly implicated ciliary pathways that regulate insulin exocytosis and intercellular communication. We present evidence of key signaling proteins on islet cilia and discuss ways in which cilia might functionally connect islet endocrine cells with the non-endocrine compartments. These discussions aim to stimulate conversations regarding the extent of cilia-controlled glucose homeostasis in health and in metabolic diseases.
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Affiliation(s)
| | - Jing W. Hughes
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
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23
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Finetti F, Onnis A, Baldari CT. IFT20: An Eclectic Regulator of Cellular Processes beyond Intraflagellar Transport. Int J Mol Sci 2022; 23:ijms232012147. [PMID: 36292997 PMCID: PMC9603483 DOI: 10.3390/ijms232012147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/06/2022] [Accepted: 10/10/2022] [Indexed: 11/16/2022] Open
Abstract
Initially discovered as the smallest component of the intraflagellar transport (IFT) system, the IFT20 protein has been found to be implicated in several unconventional mechanisms beyond its essential role in the assembly and maintenance of the primary cilium. IFT20 is now considered a key player not only in ciliogenesis but also in vesicular trafficking of membrane receptors and signaling proteins. Moreover, its ability to associate with a wide array of interacting partners in a cell-type specific manner has expanded the function of IFT20 to the regulation of intracellular degradative and secretory pathways. In this review, we will present an overview of the multifaceted role of IFT20 in both ciliated and non-ciliated cells.
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24
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Ming Z, Vining B, Bagheri-Fam S, Harley V. SOX9 in organogenesis: shared and unique transcriptional functions. Cell Mol Life Sci 2022; 79:522. [PMID: 36114905 PMCID: PMC9482574 DOI: 10.1007/s00018-022-04543-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/13/2022] [Accepted: 08/31/2022] [Indexed: 11/28/2022]
Abstract
The transcription factor SOX9 is essential for the development of multiple organs including bone, testis, heart, lung, pancreas, intestine and nervous system. Mutations in the human SOX9 gene led to campomelic dysplasia, a haploinsufficiency disorder with several skeletal malformations frequently accompanied by 46, XY sex reversal. The mechanisms underlying the diverse SOX9 functions during organ development including its post-translational modifications, the availability of binding partners, and tissue-specific accessibility to target gene chromatin. Here we summarize the expression, activities, and downstream target genes of SOX9 in molecular genetic pathways essential for organ development, maintenance, and function. We also provide an insight into understanding the mechanisms that regulate the versatile roles of SOX9 in different organs.
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Affiliation(s)
- Zhenhua Ming
- Sex Development Laboratory, Hudson Institute of Medical Research, PO Box 5152, Melbourne, VIC, 3168, Australia
- Department of Molecular and Translational Science, Monash University, Melbourne, VIC, 3800, Australia
| | - Brittany Vining
- Sex Development Laboratory, Hudson Institute of Medical Research, PO Box 5152, Melbourne, VIC, 3168, Australia
- Department of Molecular and Translational Science, Monash University, Melbourne, VIC, 3800, Australia
| | - Stefan Bagheri-Fam
- Sex Development Laboratory, Hudson Institute of Medical Research, PO Box 5152, Melbourne, VIC, 3168, Australia
- Department of Molecular and Translational Science, Monash University, Melbourne, VIC, 3800, Australia
| | - Vincent Harley
- Sex Development Laboratory, Hudson Institute of Medical Research, PO Box 5152, Melbourne, VIC, 3168, Australia.
- Department of Molecular and Translational Science, Monash University, Melbourne, VIC, 3800, Australia.
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25
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Li ZA, Cho JH, Woodhams LG, Hughes JW. Fluorescence imaging of beta cell primary cilia. Front Endocrinol (Lausanne) 2022; 13:1004136. [PMID: 36213262 PMCID: PMC9540379 DOI: 10.3389/fendo.2022.1004136] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 09/01/2022] [Indexed: 11/25/2022] Open
Abstract
Primary cilia are slender cell-surface organelles that project into the intercellular space. In pancreatic beta cells, primary cilia coordinate a variety of cell responses including GPCR signaling, calcium influx, and insulin secretion, along with likely many underappreciated roles in islet development and differentiation. To study cilia function in islet biology, direct visualization of primary cilia by microscopic methods is often a necessary first step. Ciliary abundance, distribution, and morphology are heterogeneous among islet cells and are best visualized by fluorescence microscopy, the tools for which are readily accessible to most researchers. Here we present a collection of fluorescence imaging methods that we have adopted and optimized for the observation of primary cilia in mouse and human islets. These include conventional confocal microscopy using fixed islets and pancreas sections, live-cell imaging with cilia-targeted biosensors and probes, cilia motion recordings, and quantitative analysis of primary cilia waveform in the ex vivo environment. We discuss practical considerations and limitations of our approaches as well as new tools on the horizon to facilitate the observation of primary cilia in pancreatic islets.
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Affiliation(s)
- Zipeng A. Li
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
| | - Jung Hoon Cho
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
| | - Louis G. Woodhams
- Department of Mechanical Engineering and Materials Science, Washington University McKelvey School of Engineering, Saint Louis, MO, United States
| | - Jing W. Hughes
- Department of Medicine, Washington University School of Medicine, Saint Louis, MO, United States
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26
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Sui H. Sugar, sugar: Glucose activates motion in pancreatic cilia. SCIENCE ADVANCES 2022; 8:eade4450. [PMID: 36149947 PMCID: PMC9506711 DOI: 10.1126/sciadv.ade4450] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
Pancreatic primary cilia are active and dynamic, not static antenna-like sensors as previously thought. This movement may be an important mechanism to glucose regulation.
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Affiliation(s)
- Haixin Sui
- Wadsworth Center, New York State Department of Health, Albany, NY 12237, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY 12208, USA.
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27
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Cho JH, Li ZA, Zhu L, Muegge BD, Roseman HF, Lee EY, Utterback T, Woodhams LG, Bayly PV, Hughes JW. Islet primary cilia motility controls insulin secretion. SCIENCE ADVANCES 2022; 8:eabq8486. [PMID: 36149960 PMCID: PMC9506710 DOI: 10.1126/sciadv.abq8486] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 07/13/2022] [Indexed: 06/16/2023]
Abstract
Primary cilia are specialized cell-surface organelles that mediate sensory perception and, in contrast to motile cilia and flagella, are thought to lack motility function. Here, we show that primary cilia in human and mouse pancreatic islets exhibit movement that is required for glucose-dependent insulin secretion. Islet primary cilia contain motor proteins conserved from those found in classic motile cilia, and their three-dimensional motion is dynein-driven and dependent on adenosine 5'-triphosphate and glucose metabolism. Inhibition of cilia motion blocks beta cell calcium influx and insulin secretion. Human beta cells have enriched ciliary gene expression, and motile cilia genes are altered in type 2 diabetes. Our findings redefine primary cilia as dynamic structures having both sensory and motile function and establish that pancreatic islet cilia movement plays a regulatory role in insulin secretion.
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Affiliation(s)
- Jung Hoon Cho
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, St. Louis, MO, USA
| | - Zipeng A. Li
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, St. Louis, MO, USA
| | - Lifei Zhu
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, St. Louis, MO, USA
| | - Brian D. Muegge
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, St. Louis, MO, USA
- Department of Medicine, VA Medical Center, 915 North Grand Blvd, St. Louis, MO, USA
| | - Henry F. Roseman
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, St. Louis, MO, USA
| | - Eun Young Lee
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, St. Louis, MO, USA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, South Korea
| | - Toby Utterback
- Department of Mechanical Engineering and Materials Science, Washington University McKelvey School of Engineering, 1 Brookings Drive, St. Louis, MO, USA
| | - Louis G. Woodhams
- Department of Mechanical Engineering and Materials Science, Washington University McKelvey School of Engineering, 1 Brookings Drive, St. Louis, MO, USA
| | - Philip V. Bayly
- Department of Mechanical Engineering and Materials Science, Washington University McKelvey School of Engineering, 1 Brookings Drive, St. Louis, MO, USA
| | - Jing W. Hughes
- Department of Medicine, Washington University School of Medicine, 660 South Euclid Ave, St. Louis, MO, USA
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Luxmi R, King SM. Cilia-derived vesicles: An ancient route for intercellular communication. Semin Cell Dev Biol 2022; 129:82-92. [PMID: 35346578 PMCID: PMC9378432 DOI: 10.1016/j.semcdb.2022.03.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/10/2022] [Accepted: 03/10/2022] [Indexed: 12/11/2022]
Abstract
Extracellular vesicles (EVs) provide a mechanism for intercellular communication that transports complex signals in membrane delimited structures between cells, tissues and organisms. Cells secrete EVs of various subtypes defined by the pathway leading to release and by the pathological condition of the cell. Cilia are evolutionarily conserved organelles that can act as sensory structures surveilling the extracellular environment. Here we discuss the secretory functions of cilia and their biological implications. Studies in multiple species - from the nematode Caenorhabditis elegans and the chlorophyte alga Chlamydomonas reinhardtii to mammals - have revealed that cilia shed bioactive EVs (ciliary EVs or ectosomes) by outward budding of the ciliary membrane. The content of ciliary EVs is distinct from that of other vesicles released by cells. Peptides regulate numerous aspects of metazoan physiology and development through evolutionarily conserved mechanisms. Intriguingly, cilia-derived vesicles have recently been found to mediate peptidergic signaling. C. reinhardtii releases the peptide α-amidating enzyme (PAM), bioactive amidated products and components of the peptidergic signaling machinery in ciliary EVs in a developmentally regulated manner. Considering the origin of cilia in early eukaryotes, it is likely that release of peptidergic signals in ciliary EVs represents an alternative and ancient mode of regulated secretion that cells can utilize in the absence of dedicated secretory granules.
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Affiliation(s)
- Raj Luxmi
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
| | - Stephen M King
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3305, USA.
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29
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Regulated processing and secretion of a peptide precursor in cilia. Proc Natl Acad Sci U S A 2022; 119:e2206098119. [PMID: 35878031 PMCID: PMC9351486 DOI: 10.1073/pnas.2206098119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Cilia are sensory and secretory organelles that both receive information from the environment and transmit signals. Cilia-derived vesicles (ectosomes), formed by outward budding of the ciliary membrane, carry enzymes and other bioactive products; this process represents an ancient mode of regulated secretion. Peptidergic intercellular communication controls a wide range of physiological and behavioral responses and occurs throughout eukaryotes. The Chlamydomonas reinhardtii genome encodes what appear to be numerous prepropeptides and enzymes homologous to those used to convert metazoan prepropeptides into bioactive peptide products. Since C. reinhardtii, a green alga, lack the dense core vesicles in which metazoan peptides are processed and stored, we explored the hypothesis that propeptide processing and secretion occur through the regulated release of ciliary ectosomes. A synthetic peptide (GATI-amide) that could be generated from a 91-kDa peptide precursor (proGATI) serves as a chemotactic modulator, attracting minus gametes while repelling plus gametes. Here we dissect the processing pathway that leads to formation of an amidated peptidergic sexual signal specifically on the ciliary ectosomes of plus gametes. Unlike metazoan propeptides, modeling studies identified stable domains in proGATI. Mass spectrometric analysis of a potential prohormone convertase and the amidated proGATI-derived products found in cilia and mating ectosomes link endoproteolytic cleavage to ectosome entry. Extensive posttranslational modification of proGATI confers stability to its amidated product. Analysis of this pathway affords insight into the evolution of peptidergic signaling; this will facilitate studies of the secretory functions of metazoan cilia.
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30
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Merino B, Casanueva-Álvarez E, Quesada I, González-Casimiro CM, Fernández-Díaz CM, Postigo-Casado T, Leissring MA, Kaestner KH, Perdomo G, Cózar-Castellano I. Insulin-degrading enzyme ablation in mouse pancreatic alpha cells triggers cell proliferation, hyperplasia and glucagon secretion dysregulation. Diabetologia 2022; 65:1375-1389. [PMID: 35652923 PMCID: PMC9283140 DOI: 10.1007/s00125-022-05729-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 03/11/2022] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS Type 2 diabetes is characterised by hyperglucagonaemia and perturbed function of pancreatic glucagon-secreting alpha cells but the molecular mechanisms contributing to these phenotypes are poorly understood. Insulin-degrading enzyme (IDE) is present within all islet cells, mostly in alpha cells, in both mice and humans. Furthermore, IDE can degrade glucagon as well as insulin, suggesting that IDE may play an important role in alpha cell function in vivo. METHODS We have generated and characterised a novel mouse model with alpha cell-specific deletion of Ide, the A-IDE-KO mouse line. Glucose metabolism and glucagon secretion in vivo was characterised; isolated islets were tested for glucagon and insulin secretion; alpha cell mass, alpha cell proliferation and α-synuclein levels were determined in pancreas sections by immunostaining. RESULTS Targeted deletion of Ide exclusively in alpha cells triggers hyperglucagonaemia and alpha cell hyperplasia, resulting in elevated constitutive glucagon secretion. The hyperglucagonaemia is attributable in part to dysregulation of glucagon secretion, specifically an impaired ability of IDE-deficient alpha cells to suppress glucagon release in the presence of high glucose or insulin. IDE deficiency also leads to α-synuclein aggregation in alpha cells, which may contribute to impaired glucagon secretion via cytoskeletal dysfunction. We showed further that IDE deficiency triggers impairments in cilia formation, inducing alpha cell hyperplasia and possibly also contributing to dysregulated glucagon secretion and hyperglucagonaemia. CONCLUSIONS/INTERPRETATION We propose that loss of IDE function in alpha cells contributes to hyperglucagonaemia in type 2 diabetes.
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Affiliation(s)
- Beatriz Merino
- Unidad de Excelencia Instituto de Biología y Genética Molecular (University of Valladolid-CSIC), Valladolid, Spain
| | - Elena Casanueva-Álvarez
- Unidad de Excelencia Instituto de Biología y Genética Molecular (University of Valladolid-CSIC), Valladolid, Spain
| | - Iván Quesada
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández de Elche, Elche, Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
| | - Carlos M González-Casimiro
- Unidad de Excelencia Instituto de Biología y Genética Molecular (University of Valladolid-CSIC), Valladolid, Spain
| | | | - Tamara Postigo-Casado
- Unidad de Excelencia Instituto de Biología y Genética Molecular (University of Valladolid-CSIC), Valladolid, Spain
| | - Malcolm A Leissring
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine (UCI MIND), Irvine, CA, USA
| | - Klaus H Kaestner
- Department of Genetics and Institute for Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - Germán Perdomo
- Unidad de Excelencia Instituto de Biología y Genética Molecular (University of Valladolid-CSIC), Valladolid, Spain
| | - Irene Cózar-Castellano
- Unidad de Excelencia Instituto de Biología y Genética Molecular (University of Valladolid-CSIC), Valladolid, Spain.
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain.
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31
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Li Y, Yang S, Liu Y, Qin L, Yang S. IFT20 governs mesenchymal stem cell fate through positively regulating TGF-β-Smad2/3-Glut1 signaling mediated glucose metabolism. Redox Biol 2022; 54:102373. [PMID: 35751983 PMCID: PMC9243161 DOI: 10.1016/j.redox.2022.102373] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 06/13/2022] [Indexed: 12/18/2022] Open
Abstract
Aberrant lineage allocation of mesenchymal stem cells (MSCs) could cause bone marrow osteoblast-adipocyte imbalance, and glucose as an important nutrient is required for the maintenance of the MSCs' fate and function. Intraflagellar transport 20 (IFT20) is one of the IFT complex B protein which regulates osteoblast differentiation, and bone formation, but how IFT20 regulates MSCs' fate remains undefined. Here, we demonstrated that IFT20 controls MSC lineage allocation through regulating glucose metabolism during skeletal development. IFT20 deficiency in the early stage of MSCs caused significantly shortened limbs, decreased bone mass and significant increase in marrow fat. However, deletion of IFT20 in the later stage of MSCs and osteocytes just slightly decreased bone mass and bone growth and increased marrow fat. Additionally, we found that loss of IFT20 in MSCs promotes adipocyte formation, which enhances RANKL expression and bone resorption. Conversely, ablation of IFT20 in adipocytes reversed these phenotypes. Mechanistically, loss of IFT20 in MSCs significantly decreased glucose tolerance and suppressed glucose uptake and lactate and ATP production. Moreover, loss of IFT20 significantly decreased the activity of TGF-β-Smad2/3 signaling and reduced the binding activity of Smad2/3 to Glut1 promoter to downregulate Glut1 expression. These findings indicate that IFT20 plays essential roles for preventing MSC lineage allocation into adipocytes through TGF-β-Smad2/3-Glut1 axis.
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Affiliation(s)
- Yang Li
- Department of Basic & Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Shuting Yang
- Department of Basic & Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Yang Liu
- College of Fisheries and Life Science, Dalian Ocean University, Dalian, 116023, China
| | - Ling Qin
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Shuying Yang
- Department of Basic & Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA; The Penn Center for Musculoskeletal Disorders, School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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32
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Chatenoud L, Marquet C, Valette F, Scott L, Quan J, Bu CH, Hildebrand S, Moresco EMY, Bach JF, Beutler B. Modulation of autoimmune diabetes by N-ethyl-N-nitrosourea- induced mutations in non-obese diabetic mice. Dis Model Mech 2022; 15:275575. [PMID: 35502705 PMCID: PMC9178510 DOI: 10.1242/dmm.049484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/21/2022] [Indexed: 11/20/2022] Open
Abstract
Genetic association studies of type 1 diabetes (T1D) in humans, and in congenic non-obese diabetic (NOD) mice harboring DNA segments from T1D-resistant mice, face the challenge of assigning causation to specific gene variants among many within loci that affect disease risk. Here, we created random germline mutations in NOD/NckH mice and used automated meiotic mapping to identify mutations modifying T1D incidence and age of onset. In contrast with association studies in humans or congenic NOD mice, we analyzed a relatively small number of genetic changes in each pedigree, permitting implication of specific mutations as causative. Among 844 mice from 14 pedigrees bearing 594 coding/splicing changes, we identified seven mutations that accelerated T1D development, and five that delayed or suppressed T1D. Eleven mutations affected genes not previously known to influence T1D (Xpnpep1, Herc1, Srrm2, Rapgef1, Ppl, Zfp583, Aldh1l1, Col6a1, Ccdc13, Cd200r1, Atrnl1). A suppressor mutation in Coro1a validated the screen. Mutagenesis coupled with automated meiotic mapping can detect genes in which allelic variation influences T1D susceptibility in NOD mice. Variation of some of the orthologous/paralogous genes may influence T1D susceptibility in humans.
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Affiliation(s)
- Lucienne Chatenoud
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Cindy Marquet
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Fabrice Valette
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Lindsay Scott
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jiexia Quan
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Chun Hui Bu
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Sara Hildebrand
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Eva Marie Y Moresco
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jean-François Bach
- Université Paris Cité, Institut Necker Enfants Malades, F-75015 Paris, France.,INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker Enfants Malades, F-75015 Paris, France
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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33
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Collares-Buzato CB, Carvalho CP. Is type 2 diabetes mellitus another intercellular junction-related disorder? Exp Biol Med (Maywood) 2022; 247:743-755. [PMID: 35466731 DOI: 10.1177/15353702221090464] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Type 2 diabetes mellitus (T2D) is nowadays a worldwide epidemic and has become a major challenge for health systems around the world. It is a multifactorial disorder, characterized by a chronic state of hyperglycemia caused by defects in the production as well as in the peripheral action of insulin. This minireview highlights the experimental and clinical evidence that supports the novel idea that intercellular junctions (IJs)-mediated cell-cell contacts play a role in the pathogenesis of T2D. It focuses on IJs repercussion for endocrine pancreas, intestinal barrier, and kidney dysfunctions that contribute to the onset and evolution of this metabolic disorder.
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Affiliation(s)
- Carla B Collares-Buzato
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, CEP 13083-970, Brazil
| | - Carolina Pf Carvalho
- Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, CEP 11015-020, Brazil
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34
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Pablos M, Casanueva-Álvarez E, González-Casimiro CM, Merino B, Perdomo G, Cózar-Castellano I. Primary Cilia in Pancreatic β- and α-Cells: Time to Revisit the Role of Insulin-Degrading Enzyme. Front Endocrinol (Lausanne) 2022; 13:922825. [PMID: 35832432 PMCID: PMC9271624 DOI: 10.3389/fendo.2022.922825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/24/2022] [Indexed: 12/25/2022] Open
Abstract
The primary cilium is a narrow organelle located at the surface of the cell in contact with the extracellular environment. Once underappreciated, now is thought to efficiently sense external environmental cues and mediate cell-to-cell communication, because many receptors, ion channels, and signaling molecules are highly or differentially expressed in primary cilium. Rare genetic disorders that affect cilia integrity and function, such as Bardet-Biedl syndrome and Alström syndrome, have awoken interest in studying the biology of cilium. In this review, we discuss recent evidence suggesting emerging roles of primary cilium and cilia-mediated signaling pathways in the regulation of pancreatic β- and α-cell functions, and its implications in regulating glucose homeostasis.
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Affiliation(s)
- Marta Pablos
- Department of Biochemistry, Molecular Biology and Physiology, School of Medicine, University of Valladolid, Valladolid, Spain
- *Correspondence: Marta Pablos,
| | - Elena Casanueva-Álvarez
- Unidad de Excelencia Instituto de Biología y Genética Molecular, University of Valladolid Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Carlos M. González-Casimiro
- Unidad de Excelencia Instituto de Biología y Genética Molecular, University of Valladolid Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Beatriz Merino
- Unidad de Excelencia Instituto de Biología y Genética Molecular, University of Valladolid Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Germán Perdomo
- Unidad de Excelencia Instituto de Biología y Genética Molecular, University of Valladolid Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Irene Cózar-Castellano
- Department of Biochemistry, Molecular Biology and Physiology, School of Medicine, University of Valladolid, Valladolid, Spain
- Unidad de Excelencia Instituto de Biología y Genética Molecular, University of Valladolid Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
- Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain
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35
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Waters BJ, Blum B. Axon Guidance Molecules in the Islets of Langerhans. Front Endocrinol (Lausanne) 2022; 13:869780. [PMID: 35498433 PMCID: PMC9048200 DOI: 10.3389/fendo.2022.869780] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 03/18/2022] [Indexed: 11/30/2022] Open
Abstract
The islets of Langerhans, responsible for regulating blood glucose in vertebrates, are clusters of endocrine cells distributed throughout the exocrine pancreas. The spatial architecture of the different cell types within the islets controls cell-cell communication and impacts their ability to collectively regulate glucose. Islets rely on a range of chemotactic and adhesive cues to establish and manage intercellular relationships. Growing evidence indicates that axon guidance molecules such as Slit-Robo, Semaphorin-Neuropilin, Ephrin-Eph, and Netrins, influence endocrine progenitors' cell migration to establish correct architecture during islet morphogenesis, as well as directly regulating physical cell-cell communication in the mature islet to coordinate hormone secretion. In this mini-review, we discuss what is known and not yet known about how axon guidance molecules contribute to islet morphogenesis and function.
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Affiliation(s)
| | - Barak Blum
- *Correspondence: Bayley J. Waters, ; Barak Blum,
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36
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Cho JH, Hughes JW. Cilia Action in Islets: Lessons From Mouse Models. Front Endocrinol (Lausanne) 2022; 13:922983. [PMID: 35813631 PMCID: PMC9260721 DOI: 10.3389/fendo.2022.922983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/23/2022] [Indexed: 11/30/2022] Open
Abstract
Primary cilia as a signaling organelle have garnered recent attention as a regulator of pancreatic islet function. These rod-like sensors exist on all major islet endocrine cell types and transduce a variety of external cues, while dysregulation of cilia function contributes to the development of diabetes. The complex role of islet primary cilia has been examined using genetic deletion targeting various components of cilia. In this review, we summarize experimental models for the study of islet cilia and current understanding of mechanisms of cilia regulation of islet hormone secretion. Consensus from these studies shows that pancreatic cilia perturbation can cause both endocrine and exocrine defects that are relevant to human disease. We discuss future research directions that would further elucidate cilia action in distinct groups of islet cells, including paracrine and juxtacrine regulation, GPCR signaling, and endocrine-exocrine crosstalk.
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37
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Benninger RKP, Kravets V. The physiological role of β-cell heterogeneity in pancreatic islet function. Nat Rev Endocrinol 2022; 18:9-22. [PMID: 34667280 PMCID: PMC8915749 DOI: 10.1038/s41574-021-00568-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 01/03/2023]
Abstract
Endocrine cells within the pancreatic islets of Langerhans are heterogeneous in terms of transcriptional profile, protein expression and the regulation of hormone release. Even though this heterogeneity has long been appreciated, only within the past 5 years have detailed molecular analyses led to an improved understanding of its basis. Although we are beginning to recognize why some subpopulations of endocrine cells are phenotypically different to others, arguably the most important consideration is how this heterogeneity affects the regulation of hormone release to control the homeostasis of glucose and other energy-rich nutrients. The focus of this Review is the description of how endocrine cell heterogeneity (and principally that of insulin-secreting β-cells) affects the regulation of hormone secretion within the islets of Langerhans. This discussion includes an overview of the functional characteristics of the different islet cell subpopulations and describes how they can communicate to influence islet function under basal and glucose-stimulated conditions. We further discuss how changes to the specific islet cell subpopulations or their numbers might underlie islet dysfunction in type 2 diabetes mellitus. We conclude with a discussion of several key open questions regarding the physiological role of islet cell heterogeneity.
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Affiliation(s)
- Richard K P Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Vira Kravets
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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38
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Chinipardaz Z, Liu M, Graves D, Yang S. Diabetes impairs fracture healing through disruption of cilia formation in osteoblasts. Bone 2021; 153:116176. [PMID: 34508881 PMCID: PMC9160738 DOI: 10.1016/j.bone.2021.116176] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/22/2021] [Accepted: 09/05/2021] [Indexed: 02/06/2023]
Abstract
Diabetes-associated fracture risk and impaired fracture healing represents a serious health threat. It is well known that type 1 diabetes mellitus (T1DM) impairs fracture healing due to its effect on osteoblasts and their progenitor cells. Previous studies have showed that primary cilia and intraflagellar transport protein 80 (IFT80) are critical for bone formation. However, whether TIDM impairs fracture healing due to influencing ciliary gene expression and cilia formation is unknown. Here, we investigated the effect of T1DM on primary cilia in a streptozotocin induced diabetes mouse model and examined the impact of cilia on fracture healing in osteoblasts by deletion of IFT80 in osteoblast linage using osterix (OSX)-cre (OSXcretTAIFT80f/f). The results showed that diabetes inhibited ciliary gene expression and primary cilia formation to an extent that was similar to normoglycemic mice with IFT80 deletion. Moreover, diabetic mice and normoglycemic mice with cilia loss in osteoblasts (OSXcretTAIFT80f/f) both exhibited delayed fracture healing with significantly reduced bone density and mechanical strength as well as with reduced expression of osteoblast markers, decreased angiogenesis and proliferation of bone lining cells at the fracture sites. In vitro studies showed that advanced glycation end products (AGEs) downregulated IFT80 expression in osteoblast progenitors. Moreover, AGEs and IFT80 deletion significantly reduced cilia number and length which inhibited differentiation of primary osteoblast precursors. Thus, this study for the first time report that primary cilia are essential for bone regeneration during fracture healing and loss of cilia caused by diabetes in osteoblasts resulted in defective diabetic fracture healing.
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Affiliation(s)
- Zahra Chinipardaz
- Department of Basic and Translation Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Min Liu
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dana Graves
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Shuying Yang
- Department of Basic and Translation Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA; Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Sciences, University of Pennsylvania, PA 19104, USA; The Penn Center for Musculoskeletal Disorders, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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39
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Hilgendorf KI. Primary Cilia Are Critical Regulators of White Adipose Tissue Expansion. Front Physiol 2021; 12:769367. [PMID: 34759842 PMCID: PMC8573240 DOI: 10.3389/fphys.2021.769367] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 10/04/2021] [Indexed: 12/14/2022] Open
Abstract
The primary cilium is a microtubule-based cellular protrusion found on most mammalian cell types in diverse tissues. It functions as a cellular antenna to sense and transduce a broad range of signals, including odorants, light, mechanical stimuli, and chemical ligands. This diversity in signals requires cilia to display a context and cell type-specific repertoire of receptors. Recently, primary cilia have emerged as critical regulators of metabolism. The importance of primary cilia in metabolic disease is highlighted by the clinical features of human genetic disorders with dysfunctional ciliary signaling, which include obesity and diabetes. This review summarizes the current literature on the role of primary cilia in metabolic disease, focusing on the importance of primary cilia in directing white adipose tissue expansion during obesity.
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Affiliation(s)
- Keren I Hilgendorf
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, United States
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40
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Simonett SP, Shin S, Herring JA, Bacher R, Smith LA, Dong C, Rabaglia ME, Stapleton DS, Schueler KL, Choi J, Bernstein MN, Turkewitz DR, Perez-Cervantes C, Spaeth J, Stein R, Tessem JS, Kendziorski C, Keleş S, Moskowitz IP, Keller MP, Attie AD. Identification of direct transcriptional targets of NFATC2 that promote β cell proliferation. J Clin Invest 2021; 131:e144833. [PMID: 34491912 PMCID: PMC8553569 DOI: 10.1172/jci144833] [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] [Received: 10/02/2020] [Accepted: 09/02/2021] [Indexed: 12/13/2022] Open
Abstract
The transcription factor NFATC2 induces β cell proliferation in mouse and human islets. However, the genomic targets that mediate these effects have not been identified. We expressed active forms of Nfatc2 and Nfatc1 in human islets. By integrating changes in gene expression with genomic binding sites for NFATC2, we identified approximately 2200 transcriptional targets of NFATC2. Genes induced by NFATC2 were enriched for transcripts that regulate the cell cycle and for DNA motifs associated with the transcription factor FOXP. Islets from an endocrine-specific Foxp1, Foxp2, and Foxp4 triple-knockout mouse were less responsive to NFATC2-induced β cell proliferation, suggesting the FOXP family works to regulate β cell proliferation in concert with NFATC2. NFATC2 induced β cell proliferation in both mouse and human islets, whereas NFATC1 did so only in human islets. Exploiting this species difference, we identified approximately 250 direct transcriptional targets of NFAT in human islets. This gene set enriches for cell cycle-associated transcripts and includes Nr4a1. Deletion of Nr4a1 reduced the capacity of NFATC2 to induce β cell proliferation, suggesting that much of the effect of NFATC2 occurs through its induction of Nr4a1. Integration of noncoding RNA expression, chromatin accessibility, and NFATC2 binding sites enabled us to identify NFATC2-dependent enhancer loci that mediate β cell proliferation.
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Affiliation(s)
- Shane P. Simonett
- Biochemistry Department, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Sunyoung Shin
- Department of Mathematical Sciences, University of Texas at Dallas, Richardson, Texas, USA
| | - Jacob A. Herring
- Nutrition, Dietetics and Food Science Department, Brigham Young University, Provo, Utah, USA
| | - Rhonda Bacher
- Department of Biostatistics, University of Florida, Gainesville, Florida, USA
| | - Linsin A. Smith
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, Illinois, USA
| | - Chenyang Dong
- Department of Biostatistics and Medical Informatics, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Mary E. Rabaglia
- Biochemistry Department, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Donnie S. Stapleton
- Biochemistry Department, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Kathryn L. Schueler
- Biochemistry Department, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Jeea Choi
- Department of Biostatistics and Medical Informatics, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | | | - Daniel R. Turkewitz
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Carlos Perez-Cervantes
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, Illinois, USA
| | - Jason Spaeth
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
| | - Jeffery S. Tessem
- Nutrition, Dietetics and Food Science Department, Brigham Young University, Provo, Utah, USA
| | - Christina Kendziorski
- Department of Biostatistics and Medical Informatics, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Sündüz Keleş
- Department of Biostatistics and Medical Informatics, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Ivan P. Moskowitz
- Departments of Pediatrics, Pathology, and Human Genetics, University of Chicago, Chicago, Illinois, USA
| | - Mark P. Keller
- Biochemistry Department, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Alan D. Attie
- Biochemistry Department, University of Wisconsin–Madison, Madison, Wisconsin, USA
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41
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Ishii T, Warabi E, Mann GE. Mechanisms underlying unidirectional laminar shear stress-mediated Nrf2 activation in endothelial cells: Amplification of low shear stress signaling by primary cilia. Redox Biol 2021; 46:102103. [PMID: 34425388 PMCID: PMC8379703 DOI: 10.1016/j.redox.2021.102103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 08/07/2021] [Accepted: 08/12/2021] [Indexed: 12/14/2022] Open
Abstract
Endothelial cells are sensitive to mechanical stress and respond differently to oscillatory flow versus unidirectional flow. This review highlights the mechanisms by which a wide range of unidirectional laminar shear stress induces activation of the redox sensitive antioxidant transcription factor nuclear factor-E2-related factor 2 (Nrf2) in cultured endothelial cells. We propose that fibroblast growth factor-2 (FGF-2), brain-derived neurotrophic factor (BDNF) and 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) are potential Nrf2 activators induced by laminar shear stress. Shear stress-dependent secretion of FGF-2 and its receptor-mediated signaling is tightly controlled, requiring neutrophil elastase released by shear stress, αvβ3 integrin and the cell surface glycocalyx. We speculate that primary cilia respond to low laminar shear stress (<10 dyn/cm2), resulting in secretion of insulin-like growth factor 1 (IGF-1), which facilitates αvβ3 integrin-dependent FGF-2 secretion. Shear stress induces generation of heparan-binding epidermal growth factor-like growth factor (HB-EGF), which contributes to FGF-2 secretion and gene expression. Furthermore, HB-EGF signaling modulates FGF-2-mediated NADPH oxidase 1 activation that favors casein kinase 2 (CK2)-mediated phosphorylation/activation of Nrf2 associated with caveolin 1 in caveolae. Higher shear stress (>15 dyn/cm2) induces vesicular exocytosis of BDNF from endothelial cells, and we propose that BDNF via the p75NTR receptor could induce CK2-mediated Nrf2 activation. Unidirectional laminar shear stress upregulates gene expression of FGF-2 and BDNF and generation of 15d-PGJ2, which cooperate in sustaining Nrf2 activation to protect endothelial cells against oxidative damage.
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Affiliation(s)
- Tetsuro Ishii
- School of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Eiji Warabi
- School of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8577, Japan.
| | - Giovanni E Mann
- King's British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine & Sciences, King's College London, 150 Stamford Street, London, SE1 9NH, UK.
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42
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Wu CT, Hilgendorf KI, Bevacqua RJ, Hang Y, Demeter J, Kim SK, Jackson PK. Discovery of ciliary G protein-coupled receptors regulating pancreatic islet insulin and glucagon secretion. Genes Dev 2021; 35:1243-1255. [PMID: 34385262 PMCID: PMC8415323 DOI: 10.1101/gad.348261.121] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 07/02/2021] [Indexed: 01/17/2023]
Abstract
Multiple G protein-coupled receptors (GPCRs) are expressed in pancreatic islet cells, but the majority have unknown functions. We observed specific GPCRs localized to primary cilia, a prominent signaling organelle, in pancreatic α and β cells. Loss of cilia disrupts β-cell endocrine function, but the molecular drivers are unknown. Using functional expression, we identified multiple GPCRs localized to cilia in mouse and human islet α and β cells, including FFAR4, PTGER4, ADRB2, KISS1R, and P2RY14. Free fatty acid receptor 4 (FFAR4) and prostaglandin E receptor 4 (PTGER4) agonists stimulate ciliary cAMP signaling and promote glucagon and insulin secretion by α- and β-cell lines and by mouse and human islets. Transport of GPCRs to primary cilia requires TULP3, whose knockdown in primary human and mouse islets relocalized ciliary FFAR4 and PTGER4 and impaired regulated glucagon or insulin secretion, without affecting ciliary structure. Our findings provide index evidence that regulated hormone secretion by islet α and β cells is controlled by ciliary GPCRs providing new targets for diabetes.
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Affiliation(s)
- Chien-Ting Wu
- Baxter Laboratory, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Keren I Hilgendorf
- Baxter Laboratory, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Romina J Bevacqua
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Yan Hang
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Janos Demeter
- Baxter Laboratory, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA
| | - Seung K Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California 94305, USA
- Department of Medicine, Stanford University, Stanford, California 94305, USA
| | - Peter K Jackson
- Baxter Laboratory, Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, California 94305, USA
- Department of Medicine, Stanford University, Stanford, California 94305, USA
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43
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Olajide OJ, Chapman CA. Amyloid-β (1-42) peptide induces rapid NMDA receptor-dependent alterations at glutamatergic synapses in the entorhinal cortex. Neurobiol Aging 2021; 105:296-309. [PMID: 34144329 DOI: 10.1016/j.neurobiolaging.2021.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 04/26/2021] [Accepted: 05/11/2021] [Indexed: 12/29/2022]
Abstract
The hippocampus and entorhinal cortex (EC) accumulate amyloid beta peptides (Aβ) that promote neuropathology in Alzheimer's disease, but the early effects of Aβ on excitatory synaptic transmission in the EC have not been well characterized. To assess the acute effects of Aβ1-42 on glutamatergic synapses, acute brain slices from wildtype rats were exposed to Aβ1-42 or control solution for 3 hours, and tissue was analyzed using protein immunoblotting and quantitative PCR. Presynaptically, Aβ1-42 induced marked reductions in synaptophysin, synapsin-2a mRNA, and mGluR3 mRNA, and increased both VGluT2 protein and Ca2+-activated channel KCa2.2 mRNA levels. Postsynaptically, Aβ1-42 reduced PSD95 and GluN2B protein, and also downregulated GluN2B and GluN2A mRNA, without affecting scaffolding elements SAP97 and PICK1. mGluR5 mRNA was strongly increased, while mGluR1 mRNA was unaffected. Blocking either GluN2A- or GluN2B-containing NMDA receptors did not significantly prevent synaptic changes induced by Aβ1-42, but combined blockade did prevent synaptic alterations. These findings demonstrate that Aβ1-42 rapidly disrupts glutamatergic transmission in the EC through mechanisms involving concurrent activation of GluN2A- and GluN2B-containing NMDA receptors.
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Affiliation(s)
- Olayemi Joseph Olajide
- Division of Neurobiology, Department of Anatomy, University of Ilorin, Ilorin, Nigeria; Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada
| | - Clifton Andrew Chapman
- Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, Québec, Canada.
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44
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Mustafa R, Rawas C, Mannal N, Kreiner G, Spittau B, Kamińska K, Yilmaz R, Pötschke C, Kirsch J, Liss B, Tucker KL, Parlato R. Targeted Ablation of Primary Cilia in Differentiated Dopaminergic Neurons Reduces Striatal Dopamine and Responsiveness to Metabolic Stress. Antioxidants (Basel) 2021; 10:antiox10081284. [PMID: 34439532 PMCID: PMC8389284 DOI: 10.3390/antiox10081284] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/01/2021] [Accepted: 08/09/2021] [Indexed: 12/17/2022] Open
Abstract
Primary cilia (PC) are microtubule-based protrusions of the cell membrane transducing molecular signals during brain development. Here, we report that PC are required for maintenance of Substantia nigra (SN) dopaminergic (DA) neurons highly vulnerable in Parkinson's disease (PD). Targeted blockage of ciliogenesis in differentiated DA neurons impaired striato-nigral integrity in adult mice. The relative number of SN DA neurons displaying a typical auto-inhibition of spontaneous activity in response to dopamine was elevated under control metabolic conditions, but not under metabolic stress. Strikingly, in the absence of PC, the remaining SN DA neurons were less vulnerable to the PD neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP). Our data indicate conserved PC-dependent neuroadaptive responses to DA lesions in the striatum. Moreover, PC control the integrity and dopamine response of a subtype of SN DA neurons. These results reinforce the critical role of PC as sensors of metabolic stress in PD and other disorders of the dopamine system.
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Affiliation(s)
- Rasem Mustafa
- Institute of Anatomy and Cell Biology, Heidelberg Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany; (R.M.); (J.K.); (K.L.T.)
- Institute of Applied Physiology, Ulm Medical Faculty, University of Ulm, 89081 Ulm, Germany; (C.R.); (N.M.); (C.P.); (B.L.)
| | - Chahinaz Rawas
- Institute of Applied Physiology, Ulm Medical Faculty, University of Ulm, 89081 Ulm, Germany; (C.R.); (N.M.); (C.P.); (B.L.)
| | - Nadja Mannal
- Institute of Applied Physiology, Ulm Medical Faculty, University of Ulm, 89081 Ulm, Germany; (C.R.); (N.M.); (C.P.); (B.L.)
| | - Grzegorz Kreiner
- Department of Brain Biochemistry, Maj Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Kraków, Poland;
| | - Björn Spittau
- Institute of Anatomy and Cell Biology, Department of Molecular Embryology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany;
- Anatomy and Cell Biology, Medical School OWL, Bielefeld University, 33615 Bielefeld, Germany
| | - Katarzyna Kamińska
- Department of Pharmacology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Kraków, Poland;
- Jagiellonian Center for Experimental Therapeutics, Jagiellonian University, Bobrzynskiego 14, 30-348 Kraków, Poland
| | - Rüstem Yilmaz
- Mannheim Center for Translational Neuroscience, Division of Neurodegenerative Disorders, Department of Neurology, Mannheim Medical Faculty, University of Heidelberg, 68167 Mannheim, Germany;
| | - Christina Pötschke
- Institute of Applied Physiology, Ulm Medical Faculty, University of Ulm, 89081 Ulm, Germany; (C.R.); (N.M.); (C.P.); (B.L.)
| | - Joachim Kirsch
- Institute of Anatomy and Cell Biology, Heidelberg Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany; (R.M.); (J.K.); (K.L.T.)
| | - Birgit Liss
- Institute of Applied Physiology, Ulm Medical Faculty, University of Ulm, 89081 Ulm, Germany; (C.R.); (N.M.); (C.P.); (B.L.)
- Linacre College and New College, University of Oxford, Oxford OX1 2JD, UK
| | - Kerry L. Tucker
- Institute of Anatomy and Cell Biology, Heidelberg Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany; (R.M.); (J.K.); (K.L.T.)
- Department of Biomedical Sciences, College of Osteopathic Medicine, Biddeford, ME 04005, USA
- Center for Excellence in the Neurosciences, University of New England, Biddeford, ME 04005, USA
| | - Rosanna Parlato
- Institute of Anatomy and Cell Biology, Heidelberg Medical Faculty, University of Heidelberg, 69120 Heidelberg, Germany; (R.M.); (J.K.); (K.L.T.)
- Institute of Applied Physiology, Ulm Medical Faculty, University of Ulm, 89081 Ulm, Germany; (C.R.); (N.M.); (C.P.); (B.L.)
- Mannheim Center for Translational Neuroscience, Division of Neurodegenerative Disorders, Department of Neurology, Mannheim Medical Faculty, University of Heidelberg, 68167 Mannheim, Germany;
- Correspondence: ; Tel.: +49-621-3835-611
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45
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Baldi P, Alhassen W, Chen S, Nguyen H, Khoudari M, Alachkar A. Large-scale analysis reveals spatiotemporal circadian patterns of cilia transcriptomes in the primate brain. J Neurosci Res 2021; 99:2610-2624. [PMID: 34310750 DOI: 10.1002/jnr.24919] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 06/08/2021] [Accepted: 06/24/2021] [Indexed: 01/13/2023]
Abstract
Cilia are dynamic subcellular systems, with core structural and functional components operating in a highly coordinated manner. Since many environmental stimuli sensed by cilia are circadian in nature, it is reasonable to speculate that genes encoding cilia structural and functional components follow rhythmic circadian patterns of expression. Using computational methods and the largest spatiotemporal gene expression atlas of primates, we identified and analyzed the circadian rhythmic expression of cilia genes across 22 primate brain areas. We found that around 73% of cilia transcripts exhibited circadian rhythmicity across at least one of 22 brain regions. In 12 brain regions, cilia transcriptomes were significantly enriched with circadian oscillating transcripts, as compared to the rest of the transcriptome. The phase of the cilia circadian transcripts deviated from the phase of the majority of the background circadian transcripts, and transcripts coding for cilia basal body components accounted for the majority of cilia circadian transcripts. In addition, adjacent or functionally connected brain nuclei had large overlapping complements of circadian cilia genes. Most remarkably, cilia circadian transcripts shared across the basal ganglia nuclei and the prefrontal cortex peaked in these structures in sequential fashion that is similar to the sequential order of activation of the basal ganglia-cortical circuitry in connection with movement coordination, albeit on completely different timescales. These findings support a role for the circadian spatiotemporal orchestration of cilia gene expression in the normal physiology of the basal ganglia-cortical circuit and motor control. Studying orchestrated cilia rhythmicity in the basal ganglia-cortical circuits and other brain circuits may help develop better functional models, and shed light on the causal effects cilia functions have on these circuits and on the regulation of movement and other behaviors.
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Affiliation(s)
- Pierre Baldi
- Department of Computer Science, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA.,Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA
| | - Wedad Alhassen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
| | - Siwei Chen
- Department of Computer Science, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA.,Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA
| | - Henry Nguyen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
| | - Mohammad Khoudari
- Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
| | - Amal Alachkar
- Institute for Genomics and Bioinformatics, School of Information and Computer Sciences, University of California-Irvine, Irvine, CA, USA.,Department of Pharmaceutical Sciences, School of Pharmacy, University of California-Irvine, Irvine, CA, USA
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46
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Ng XW, Chung YH, Piston DW. Intercellular Communication in the Islet of Langerhans in Health and Disease. Compr Physiol 2021; 11:2191-2225. [PMID: 34190340 DOI: 10.1002/cphy.c200026] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Blood glucose homeostasis requires proper function of pancreatic islets, which secrete insulin, glucagon, and somatostatin from the β-, α-, and δ-cells, respectively. Each islet cell type is equipped with intrinsic mechanisms for glucose sensing and secretory actions, but these intrinsic mechanisms alone cannot explain the observed secretory profiles from intact islets. Regulation of secretion involves interconnected mechanisms among and between islet cell types. Islet cells lose their normal functional signatures and secretory behaviors upon dispersal as compared to intact islets and in vivo. In dispersed islet cells, the glucose response of insulin secretion is attenuated from that seen from whole islets, coordinated oscillations in membrane potential and intracellular Ca2+ activity, as well as the two-phase insulin secretion profile, are missing, and glucagon secretion displays higher basal secretion profile and a reverse glucose-dependent response from that of intact islets. These observations highlight the critical roles of intercellular communication within the pancreatic islet, and how these communication pathways are crucial for proper hormonal and nonhormonal secretion and glucose homeostasis. Further, misregulated secretions of islet secretory products that arise from defective intercellular islet communication are implicated in diabetes. Intercellular communication within the islet environment comprises multiple mechanisms, including electrical synapses from gap junctional coupling, paracrine interactions among neighboring cells, and direct cell-to-cell contacts in the form of juxtacrine signaling. In this article, we describe the various mechanisms that contribute to proper islet function for each islet cell type and how intercellular islet communications are coordinated among the same and different islet cell types. © 2021 American Physiological Society. Compr Physiol 11:2191-2225, 2021.
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Affiliation(s)
- Xue W Ng
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - Yong H Chung
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
| | - David W Piston
- Department of Cell Biology and Physiology, Washington University, St Louis, Missouri, USA
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Li X, Yang S, Deepk V, Chinipardaz Z, Yang S. Identification of Cilia in Different Mouse Tissues. Cells 2021; 10:cells10071623. [PMID: 34209603 PMCID: PMC8307782 DOI: 10.3390/cells10071623] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/13/2021] [Accepted: 06/18/2021] [Indexed: 12/16/2022] Open
Abstract
Cilia are microtubule-based hair-like organelles that extend from the cell surface. However, the existence and distribution of cilia in each organ and tissue at the postnatal stage in vivo remain largely unknown. In this study, we defined cilia distribution and arrangement and measured the ciliary lengths and the percentage of ciliated cells in different organs and tissues in vivo by using cilium dual reporter-expressing transgenic mice. Cilia were identified by the presence of ARL13B with an mCherry+ signal, and the cilium basal body was identified by the presence of Centrin2 with a GFP+ signal. Here, we provide in vivo evidence that chondrocytes and cells throughout bones have cilia. Most importantly, we reveal that: 1. primary cilia are present in hepatocytes; 2. no cilia but many centrioles are distributed on the apical cell surface in the gallbladder, intestine, and thyroid epithelia; 3. cilia on the cerebral cortex are well oriented, pointing to the center of the brain; 4. ARL13B+ inclusion is evident in the thyroid and islets of Langerhans; and 5. approximately 2% of cilia show irregular movement in nucleus pulposus extracellular fluid. This study reveals the existence and distribution of cilia and centrioles in different tissues and organs, and provides new insights for further comprehensive study of ciliary function in these organs and tissues.
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Affiliation(s)
- Xinhua Li
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (X.L.); (S.Y.); (V.D.); (Z.C.)
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200080, China
- Department of Spinal Surgery, East Hospital, School of Medicine, Tongji University, Shanghai 200120, China
| | - Shuting Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (X.L.); (S.Y.); (V.D.); (Z.C.)
| | - Vishwa Deepk
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (X.L.); (S.Y.); (V.D.); (Z.C.)
| | - Zahra Chinipardaz
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (X.L.); (S.Y.); (V.D.); (Z.C.)
| | - Shuying Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; (X.L.); (S.Y.); (V.D.); (Z.C.)
- The Penn Center for Musculoskeletal Disorders, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
- Correspondence: ; Tel.: +1-215-898-2685; Fax: +1-215-573-2324
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48
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Bäck N, Mains RE, Eipper BA. PAM: diverse roles in neuroendocrine cells, cardiomyocytes, and green algae. FEBS J 2021; 289:4470-4496. [PMID: 34089560 DOI: 10.1111/febs.16049] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/28/2021] [Accepted: 06/02/2021] [Indexed: 12/13/2022]
Abstract
Our understanding of the ways in which peptides are used for communication in the nervous and endocrine systems began with the identification of oxytocin, vasopressin, and insulin, each of which is stored in electron-dense granules, ready for release in response to an appropriate stimulus. For each of these peptides, entry of its newly synthesized precursor into the ER lumen is followed by transport through the secretory pathway, exposing the precursor to a sequence of environments and enzymes that produce the bioactive products stored in mature granules. A final step in the biosynthesis of many peptides is C-terminal amidation by peptidylglycine α-amidating monooxygenase (PAM), an ascorbate- and copper-dependent membrane enzyme that enters secretory granules along with its soluble substrates. Biochemical and cell biological studies elucidated the highly conserved mechanism for amidated peptide production and raised many questions about PAM trafficking and the effects of PAM on cytoskeletal organization and gene expression. Phylogenetic studies and the discovery of active PAM in the ciliary membranes of Chlamydomonas reinhardtii, a green alga lacking secretory granules, suggested that a PAM-like enzyme was present in the last eukaryotic common ancestor. While the catalytic features of human and C. reinhardtii PAM are strikingly similar, the trafficking of PAM in C. reinhardtii and neuroendocrine cells and secretion of its amidated products differ. A comparison of PAM function in neuroendocrine cells, atrial myocytes, and C. reinhardtii reveals multiple ways in which altered trafficking allows PAM to accomplish different tasks in different species and cell types.
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Affiliation(s)
- Nils Bäck
- Department of Anatomy, University of Helsinki, Finland
| | - Richard E Mains
- Department of Neuroscience, UConn Health, Farmington, CT, USA
| | - Betty A Eipper
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, USA
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49
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Miranda MA, Macias-Velasco JF, Lawson HA. Pancreatic β-cell heterogeneity in health and diabetes: classes, sources, and subtypes. Am J Physiol Endocrinol Metab 2021; 320:E716-E731. [PMID: 33586491 PMCID: PMC8238131 DOI: 10.1152/ajpendo.00649.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Pancreatic β-cells perform glucose-stimulated insulin secretion, a process at the center of type 2 diabetes etiology. Efforts to understand how β-cells behave in healthy and stressful conditions have revealed a wide degree of morphological, functional, and transcriptional heterogeneity. Sources of heterogeneity include β-cell topography, developmental origin, maturation state, and stress response. Advances in sequencing and imaging technologies have led to the identification of β-cell subtypes, which play distinct roles in the islet niche. This review examines β-cell heterogeneity from morphological, functional, and transcriptional perspectives, and considers the relevance of topography, maturation, development, and stress response. It also discusses how these factors have been used to identify β-cell subtypes, and how heterogeneity is impacted by diabetes. We examine open questions in the field and discuss recent technological innovations that could advance understanding of β-cell heterogeneity in health and disease.
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Affiliation(s)
- Mario A Miranda
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri
| | - Juan F Macias-Velasco
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri
| | - Heather A Lawson
- Department of Genetics, Washington University School of Medicine, Saint Louis, Missouri
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Croze ML, Flisher MF, Guillaume A, Tremblay C, Noguchi GM, Granziera S, Vivot K, Castillo VC, Campbell SA, Ghislain J, Huising MO, Poitout V. Free fatty acid receptor 4 inhibitory signaling in delta cells regulates islet hormone secretion in mice. Mol Metab 2021; 45:101166. [PMID: 33484949 PMCID: PMC7873385 DOI: 10.1016/j.molmet.2021.101166] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 01/08/2021] [Accepted: 01/11/2021] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Maintenance of glucose homeostasis requires the precise regulation of hormone secretion from the endocrine pancreas. Free fatty acid receptor 4 (FFAR4/GPR120) is a G protein-coupled receptor whose activation in islets of Langerhans promotes insulin and glucagon secretion and inhibits somatostatin secretion. However, the contribution of individual islet cell types (α, β, and δ cells) to the insulinotropic and glucagonotropic effects of GPR120 remains unclear. As gpr120 mRNA is enriched in somatostatin-secreting δ cells, we hypothesized that GPR120 activation stimulates insulin and glucagon secretion via inhibition of somatostatin release. METHODS Glucose tolerance tests were performed in mice after administration of selective GPR120 agonist Compound A. Insulin, glucagon, and somatostatin secretion were measured in static incubations of isolated mouse islets in response to endogenous (ω-3 polyunsaturated fatty acids) and/or pharmacological (Compound A and AZ-13581837) GPR120 agonists. The effect of Compound A on hormone secretion was tested further in islets isolated from mice with global or somatostatin cell-specific knock-out of gpr120. Gpr120 expression was assessed in pancreatic sections by RNA in situ hybridization. Cyclic AMP (cAMP) and calcium dynamics in response to pharmacological GPR120 agonists were measured specifically in α, β, and δ cells in intact islets using cAMPER and GCaMP6 reporter mice, respectively. RESULTS Acute exposure to Compound A increased glucose tolerance, circulating insulin, and glucagon levels in vivo. Endogenous and/or pharmacological GPR120 agonists reduced somatostatin secretion in isolated islets and concomitantly demonstrated dose-dependent potentiation of glucose-stimulated insulin secretion and arginine-stimulated glucagon secretion. Gpr120 was enriched in δ cells. Pharmacological GPR120 agonists reduced cAMP and calcium levels in δ cells but increased these signals in α and β cells. Compound A-mediated inhibition of somatostatin secretion was insensitive to pertussis toxin. The effect of Compound A on hormone secretion was completely absent in islets from mice with either global or somatostatin cell-specific deletion of gpr120 and partially reduced upon blockade of somatostatin receptor signaling by cyclosomatostatin. CONCLUSIONS Inhibitory GPR120 signaling in δ cells contributes to both insulin and glucagon secretion in part by mitigating somatostatin release.
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Affiliation(s)
- Marine L Croze
- Montreal Diabetes Research Center, CRCHUM, Montréal, QC, Canada
| | - Marcus F Flisher
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California Davis, Davis, CA, USA
| | | | | | - Glyn M Noguchi
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California Davis, Davis, CA, USA
| | | | - Kevin Vivot
- Montreal Diabetes Research Center, CRCHUM, Montréal, QC, Canada
| | - Vincent C Castillo
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California Davis, Davis, CA, USA
| | | | - Julien Ghislain
- Montreal Diabetes Research Center, CRCHUM, Montréal, QC, Canada
| | - Mark O Huising
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California Davis, Davis, CA, USA; Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, CA, USA
| | - Vincent Poitout
- Montreal Diabetes Research Center, CRCHUM, Montréal, QC, Canada; Department of Medicine, Université de Montréal, Montréal, QC, Canada.
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