1
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Tharp KM, Higuchi-Sanabria R, Timblin GA, Ford B, Garzon-Coral C, Schneider C, Muncie JM, Stashko C, Daniele JR, Moore AS, Frankino PA, Homentcovschi S, Manoli SS, Shao H, Richards AL, Chen KH, Hoeve JT, Ku GM, Hellerstein M, Nomura DK, Saijo K, Gestwicki J, Dunn AR, Krogan NJ, Swaney DL, Dillin A, Weaver VM. Adhesion-mediated mechanosignaling forces mitohormesis. Cell Metab 2021; 33:1322-1341.e13. [PMID: 34019840 PMCID: PMC8266765 DOI: 10.1016/j.cmet.2021.04.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/09/2021] [Accepted: 04/26/2021] [Indexed: 12/11/2022]
Abstract
Mitochondria control eukaryotic cell fate by producing the energy needed to support life and the signals required to execute programed cell death. The biochemical milieu is known to affect mitochondrial function and contribute to the dysfunctional mitochondrial phenotypes implicated in cancer and the morbidities of aging. However, the physical characteristics of the extracellular matrix are also altered in cancerous and aging tissues. Here, we demonstrate that cells sense the physical properties of the extracellular matrix and activate a mitochondrial stress response that adaptively tunes mitochondrial function via solute carrier family 9 member A1-dependent ion exchange and heat shock factor 1-dependent transcription. Overall, our data indicate that adhesion-mediated mechanosignaling may play an unappreciated role in the altered mitochondrial functions observed in aging and cancer.
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Affiliation(s)
- Kevin M Tharp
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ryo Higuchi-Sanabria
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Greg A Timblin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Breanna Ford
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA 94720, USA; Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Carlos Garzon-Coral
- Chemical Engineering Department, Stanford University, Stanford, CA 94305, USA
| | - Catherine Schneider
- Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jonathon M Muncie
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Connor Stashko
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joseph R Daniele
- MD Anderson Cancer Center, South Campus Research, Houston, CA 77054, USA
| | - Andrew S Moore
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Phillip A Frankino
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Stefan Homentcovschi
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Sagar S Manoli
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Hao Shao
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alicia L Richards
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kuei-Ho Chen
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Johanna Ten Hoeve
- UCLA Metabolomics Center, Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Gregory M Ku
- Diabetes Center, Division of Endocrinology and Metabolism, Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Marc Hellerstein
- Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Daniel K Nomura
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA 94720, USA; Novartis, Berkeley Center for Proteomics and Chemistry Technologies and Department of Chemistry, University of California Berkeley, Berkeley, CA 94720, USA
| | - Karou Saijo
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jason Gestwicki
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alexander R Dunn
- Department of Nutritional Sciences and Toxicology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Nevan J Krogan
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Danielle L Swaney
- Quantitative Biosciences Institute (QBI), J. David Gladstone Institutes, Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Andrew Dillin
- Department of Molecular & Cellular Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, CA 94597, USA
| | - Valerie M Weaver
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, University of California, San Francisco, San Francisco, CA 94143, USA; Department of Bioengineering and Therapeutic Sciences and Department of Radiation Oncology, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, and The Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
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2
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Abstract
Gpr27 is a highly conserved, orphan G protein coupled receptor (GPCR) previously implicated in pancreatic beta cell insulin transcription and glucose-stimulated insulin secretion in vitro. Here, we characterize a whole-body mouse knockout of Gpr27. Gpr27 knockout mice were born at expected Mendelian ratios and exhibited no gross abnormalities. Insulin and Pdx1 mRNA in Gpr27 knockout islets were reduced by 30%, but this did not translate to a reduction in islet insulin content or beta cell mass. Gpr27 knockout mice exhibited slightly worsened glucose tolerance with lower plasma insulin levels while maintaining similar insulin tolerance. Unexpectedly, Gpr27 deletion reduced expression of Eif4e3, a neighboring gene, likely by deleting transcription start sites on the anti-sense strand of the Gpr27 coding exon. Our data confirm that loss of Gpr27 reduces insulin mRNA in vivo but has only minor effects on glucose tolerance.
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Affiliation(s)
| | - Nicholas Yiv
- Diabetes Center, UCSF, San Francisco, CA, 94143, USA
| | - Thomas G Hennings
- Diabetes Center, UCSF, San Francisco, CA, 94143, USA
- Biomedical Sciences Graduate Program, UCSF, San Francisco, CA, 94143, USA
| | - Yaohuan Zhang
- Metabolic Biology Graduate Program, UCB, Berkeley, CA, 94720, USA
| | - Gregory M Ku
- Diabetes Center, UCSF, San Francisco, CA, 94143, USA.
- Division of Endocrinology and Metabolism, Department of Medicine, UCSF, San Francisco, CA, 94143, USA.
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3
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Hennings TG, Chopra DG, DeLeon ER, VanDeusen HR, Sesaki H, Merrins MJ, Ku GM. In Vivo Deletion of β-Cell Drp1 Impairs Insulin Secretion Without Affecting Islet Oxygen Consumption. Endocrinology 2018; 159:3245-3256. [PMID: 30052866 PMCID: PMC6107751 DOI: 10.1210/en.2018-00445] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/16/2018] [Indexed: 01/17/2023]
Abstract
Mitochondria are dynamic organelles that undergo frequent fission and fusion events. Mitochondrial fission is required for ATP production, the tricarboxylic acid cycle, and processes beyond metabolism in a cell-type specific manner. Ex vivo and cell line studies have demonstrated that Drp1, a central regulator of mitochondrial fission, is required for glucose-stimulated insulin secretion (GSIS) in pancreatic β cells. Herein, we set out to interrogate the role of Drp1 in β-cell insulin secretion in vivo. We generated β-cell-specific Drp1 knockout (KO) mice (Drp1β-KO) by crossing a conditional allele of Drp1 to Ins1cre mice, in which Cre recombinase replaces the coding region of the Ins1 gene. Drp1β-KO mice were glucose intolerant due to impaired GSIS but did not progress to fasting hyperglycemia as adults. Despite markedly abnormal mitochondrial morphology, Drp1β-KO islets exhibited normal oxygen consumption rates and an unchanged glucose threshold for intracellular calcium mobilization. Instead, the most profound consequences of β-cell Drp1 deletion were impaired second-phase insulin secretion and impaired glucose-stimulated amplification of insulin secretion. Our data establish Drp1 as an important regulator of insulin secretion in vivo and demonstrate a role for Drp1 in metabolic amplification and calcium handling without affecting oxygen consumption.
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Affiliation(s)
- Thomas G Hennings
- Diabetes Center, University of California, San Francisco, San Francisco, California
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, California
| | - Deeksha G Chopra
- Diabetes Center, University of California, San Francisco, San Francisco, California
| | - Elizabeth R DeLeon
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Wisconsin-Madison, Madison, Wisconsin
| | - Halena R VanDeusen
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Wisconsin-Madison, Madison, Wisconsin
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Wisconsin-Madison, Madison, Wisconsin
- William S. Middleton Memorial Veterans Hospital, Madison, Wisconsin
| | - Gregory M Ku
- Diabetes Center, University of California, San Francisco, San Francisco, California
- Department of Medicine, Division of Endocrinology and Metabolism, University of California, San Francisco, San Francisco, California
- Correspondence: Gregory M. Ku, MD, PhD, 513 Parnassus Avenue, HSW 1027, San Francisco, California 94143. E-mail:
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4
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Lee J, Pappalardo Z, Chopra DG, Hennings TG, Vaughn I, Lan C, Choe JJ, Ang K, Chen S, Arkin M, McManus MT, German MS, Ku GM. A Genetic Interaction Map of Insulin Production Identifies Mfi as an Inhibitor of Mitochondrial Fission. Endocrinology 2018; 159:3321-3330. [PMID: 30059978 PMCID: PMC6112596 DOI: 10.1210/en.2018-00426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 07/23/2018] [Indexed: 11/19/2022]
Abstract
Insulin production by the pancreatic β cell is critical for the glucose homeostasis of the whole organism. Although the transcription factors required for insulin production are known, the upstream pathways that control insulin production are less clear. To further elucidate this regulatory network, we created a genetic interaction map of insulin production by performing ∼20,000 pairwise RNA interference knockdowns of insulin promoter regulators. Our map correctly predicted known physical complexes in the electron transport chain and a role for Spry2 in the unfolded protein response. To further validate our map, we used it to predict the function of an unannotated gene encoding a 37-kDa protein with no identifiable domains we have termed mitochondrial fission factor interactor (Mfi). We have shown that Mfi is a binding partner of the mitochondrial fission factor and that Mfi inhibits dynamin-like protein 1 recruitment to mitochondria. Our data provide a resource to understand the regulatory network of insulin promoter activity.
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Affiliation(s)
- Jessica Lee
- Diabetes Center, University of California, San Francisco, San Francisco, California
| | - Zachary Pappalardo
- Diabetes Center, University of California, San Francisco, San Francisco, California
| | | | - Thomas G Hennings
- Diabetes Center, University of California, San Francisco, San Francisco, California
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, California
| | - Ian Vaughn
- Diabetes Center, University of California, San Francisco, San Francisco, California
| | - Christopher Lan
- Diabetes Center, University of California, San Francisco, San Francisco, California
| | - Justin J Choe
- Diabetes Center, University of California, San Francisco, San Francisco, California
| | - Kenny Ang
- Small Molecules Discovery Center, University of California, San Francisco, San Francisco, California
| | - Steven Chen
- Small Molecules Discovery Center, University of California, San Francisco, San Francisco, California
| | - Michelle Arkin
- Small Molecules Discovery Center, University of California, San Francisco, San Francisco, California
| | - Michael T McManus
- Diabetes Center, University of California, San Francisco, San Francisco, California
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California
| | - Michael S German
- Diabetes Center, University of California, San Francisco, San Francisco, California
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Francisco, San Francisco, California
| | - Gregory M Ku
- Diabetes Center, University of California, San Francisco, San Francisco, California
- Division of Endocrinology and Metabolism, Department of Medicine, University of California San Francisco, San Francisco, California
- Correspondence: Gregory M. Ku, MD, PhD, Diabetes Center, University of California, San Francisco, 513 Parnassus Avenue, HSW 1002A, Box 0534, San Francisco, California 94143. E-mail:
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5
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Pappalardo Z, Gambhir Chopra D, Hennings TG, Richards H, Choe J, Yang K, Baeyens L, Ang K, Chen S, Arkin M, German MS, McManus MT, Ku GM. A Whole-Genome RNA Interference Screen Reveals a Role for Spry2 in Insulin Transcription and the Unfolded Protein Response. Diabetes 2017; 66:1703-1712. [PMID: 28246293 PMCID: PMC5440024 DOI: 10.2337/db16-0962] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 02/16/2017] [Indexed: 12/18/2022]
Abstract
Insulin production by the pancreatic β-cell is required for normal glucose homeostasis. While key transcription factors that bind to the insulin promoter are known, relatively little is known about the upstream regulators of insulin transcription. Using a whole-genome RNA interference screen, we uncovered 26 novel regulators of insulin transcription that regulate diverse processes including oxidative phosphorylation, vesicle traffic, and the unfolded protein response (UPR). We focused on Spry2-a gene implicated in human type 2 diabetes by genome-wide association studies but without a clear connection to glucose homeostasis. We showed that Spry2 is a novel UPR target and its upregulation is dependent on PERK. Knockdown of Spry2 resulted in reduced expression of Serca2, reduced endoplasmic reticulum calcium levels, and induction of the UPR. Spry2 deletion in the adult mouse β-cell caused hyperglycemia and hypoinsulinemia. Our study greatly expands the compendium of insulin promoter regulators and demonstrates a novel β-cell link between Spry2 and human diabetes.
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Affiliation(s)
- Zachary Pappalardo
- Diabetes Center, University of California, San Francisco, San Francisco, CA
| | | | - Thomas G Hennings
- Diabetes Center, University of California, San Francisco, San Francisco, CA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA
| | - Hunter Richards
- Diabetes Center, University of California, San Francisco, San Francisco, CA
| | - Justin Choe
- Diabetes Center, University of California, San Francisco, San Francisco, CA
| | - Katherine Yang
- Diabetes Center, University of California, San Francisco, San Francisco, CA
| | - Luc Baeyens
- Diabetes Center, University of California, San Francisco, San Francisco, CA
| | - Kenny Ang
- Small Molecule Discovery Center, University of California, San Francisco, San Francisco, CA
| | - Steven Chen
- Small Molecule Discovery Center, University of California, San Francisco, San Francisco, CA
| | - Michelle Arkin
- Small Molecule Discovery Center, University of California, San Francisco, San Francisco, CA
| | - Michael S German
- Diabetes Center, University of California, San Francisco, San Francisco, CA
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, San Francisco, CA
| | - Michael T McManus
- Diabetes Center, University of California, San Francisco, San Francisco, CA
- Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA
| | - Gregory M Ku
- Diabetes Center, University of California, San Francisco, San Francisco, CA
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Francisco, San Francisco, CA
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6
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Chamberlain CE, Scheel DW, McGlynn K, Kim H, Miyatsuka T, Wang J, Nguyen V, Zhao S, Mavropoulos A, Abraham AG, O’Neill E, Ku GM, Cobb MH, Martin GR, German MS. Menin determines K-RAS proliferative outputs in endocrine cells. J Clin Invest 2014; 124:4093-101. [PMID: 25133424 PMCID: PMC4153699 DOI: 10.1172/jci69004] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 06/26/2014] [Indexed: 12/19/2022] Open
Abstract
Endocrine cell proliferation fluctuates dramatically in response to signals that communicate hormone demand. The genetic alterations that override these controls in endocrine tumors often are not associated with oncogenes common to other tumor types, suggesting that unique pathways govern endocrine proliferation. Within the pancreas, for example, activating mutations of the prototypical oncogene KRAS drive proliferation in all pancreatic ductal adenocarcimomas but are never found in pancreatic endocrine tumors. Therefore, we asked how cellular context impacts K-RAS signaling. We found that K-RAS paradoxically suppressed, rather than promoted, growth in pancreatic endocrine cells. Inhibition of proliferation by K-RAS depended on antiproliferative RAS effector RASSF1A and blockade of the RAS-activated proproliferative RAF/MAPK pathway by tumor suppressor menin. Consistent with this model, a glucagon-like peptide 1 (GLP1) agonist, which stimulates ERK1/2 phosphorylation, did not affect endocrine cell proliferation by itself, but synergistically enhanced proliferation when combined with a menin inhibitor. In contrast, inhibition of MAPK signaling created a synthetic lethal interaction in the setting of menin loss. These insights suggest potential strategies both for regenerating pancreatic β cells for people with diabetes and for targeting menin-sensitive endocrine tumors.
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Affiliation(s)
- Chester E. Chamberlain
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - David W. Scheel
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Kathleen McGlynn
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Hail Kim
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Takeshi Miyatsuka
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Juehu Wang
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Vinh Nguyen
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Shuhong Zhao
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Anastasia Mavropoulos
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Aswin G. Abraham
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Eric O’Neill
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Gregory M. Ku
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Melanie H. Cobb
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Gail R. Martin
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
| | - Michael S. German
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, Diabetes Center, and Department of Anatomy, UCSF, San Francisco, California, USA. CRUK/MRC Oxford Institute, Department of Oncology, University of Oxford, Oxford, United Kingdom. Department of Surgery and Department of Medicine, UCSF, San Francisco, California, USA
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7
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Ku GM, Kim H, Vaughn IW, Hangauer MJ, Myung Oh C, German MS, McManus MT. Research resource: RNA-Seq reveals unique features of the pancreatic β-cell transcriptome. Mol Endocrinol 2012; 26:1783-92. [PMID: 22915829 DOI: 10.1210/me.2012-1176] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The pancreatic β-cell is critical for the maintenance of glycemic control. Knowing the compendium of genes expressed in β-cells will further our understanding of this critical cell type and may allow the identification of future antidiabetes drug targets. Here, we report the use of next-generation sequencing to obtain nearly 1 billion reads from the polyadenylated RNA of islets and purified β-cells from mice. These data reveal novel examples of β-cell-specific splicing events, promoter usage, and over 1000 long intergenic noncoding RNA expressed in mouse β-cells. Many of these long intergenic noncoding RNA are β-cell specific, and we hypothesize that this large set of novel RNA may play important roles in β-cell function. Our data demonstrate unique features of the β-cell transcriptome.
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Affiliation(s)
- Gregory M Ku
- 513 Parnassus Avenue, Box 0534, San Francisco, California 94143-0534, USA
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8
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Ku GM, Pappalardo Z, Luo CC, German MS, McManus MT. An siRNA screen in pancreatic beta cells reveals a role for Gpr27 in insulin production. PLoS Genet 2012; 8:e1002449. [PMID: 22253604 PMCID: PMC3257298 DOI: 10.1371/journal.pgen.1002449] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 11/18/2011] [Indexed: 11/18/2022] Open
Abstract
The prevalence of type 2 diabetes in the United States is projected to double or triple by 2050. We reasoned that the genes that modulate insulin production might be new targets for diabetes therapeutics. Therefore, we developed an siRNA screening system to identify genes important for the activity of the insulin promoter in beta cells. We created a subclone of the MIN6 mouse pancreatic beta cell line that expresses destabilized GFP under the control of a 362 base pair fragment of the human insulin promoter and the mCherry red fluorescent protein under the control of the constitutively active rous sarcoma virus promoter. The ratio of the GFP to mCherry fluorescence of a cell indicates its insulin promoter activity. As G protein coupled receptors (GPCRs) have emerged as novel targets for diabetes therapies, we used this cell line to screen an siRNA library targeting all known mouse GPCRs. We identified several known GPCR regulators of insulin secretion as regulators of the insulin promoter. One of the top positive regulators was Gpr27, an orphan GPCR with no known role in beta cell function. We show that knockdown of Gpr27 reduces endogenous mouse insulin promoter activity and glucose stimulated insulin secretion. Furthermore, we show that Pdx1 is important for Gpr27's effect on the insulin promoter and insulin secretion. Finally, the over-expression of Gpr27 in 293T cells increases inositol phosphate levels, while knockdown of Gpr27 in MIN6 cells reduces inositol phosphate levels, suggesting this orphan GPCR might couple to Gq/11. In summary, we demonstrate a MIN6-based siRNA screening system that allows rapid identification of novel positive and negative regulators of the insulin promoter. Using this system, we identify Gpr27 as a positive regulator of insulin production. Pancreatic beta cells are the only physiologic source of insulin. When these cells are destroyed in type 1 diabetics, there is uncontrolled hyperglycemia from complete insulin deficiency. In type 2 diabetes, these same cells fail to increase insulin secretion to compensate for peripheral insulin resistance leading to relative insulin deficiency. We constructed a novel screening system to find new regulators of insulin production in this critical cell type. Here, we describe a screen of the G protein coupled receptors (GPCRs) and show a role for orphan GPCR, Gpr27, in insulin promoter activity and insulin secretion. We propose that Gpr27 is a novel target for diabetes therapeutics.
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Affiliation(s)
- Gregory M. Ku
- Diabetes Center, University of California San Francisco, San Francisco, California, United States of America
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Zachary Pappalardo
- Diabetes Center, University of California San Francisco, San Francisco, California, United States of America
| | - Chun Chieh Luo
- Diabetes Center, University of California San Francisco, San Francisco, California, United States of America
| | - Michael S. German
- Diabetes Center, University of California San Francisco, San Francisco, California, United States of America
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Michael T. McManus
- Diabetes Center, University of California San Francisco, San Francisco, California, United States of America
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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9
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Abstract
Given the importance of the Rho GTPase family member Rac1 and the Rac1/Cdc42 effector PAK1 in T-cell activation, we investigated the requirements for their activation by the T-cell receptor (TCR). Rac1 and PAK1 activation required the tyrosine kinases ZAP-70 and Syk, but not the cytoplasmic adaptor Slp-76. Surprisingly, PAK1 was activated in the absence of the transmembrane adaptor LAT while Rac1 was not. However, efficient PAK1 activation required its binding sites for Rho GTPases and for PIX, a guanine nucleotide exchange factor for Rho GTPases. The overexpression of ssPIX that either cannot bind PAK1 or lacks GEF function blocked PAK1 activation. These data suggest that a PAK1-PIX complex is recruited to appropriate sites for activation and that PIX is required for Rho family GTPase activation upstream of PAK1. Furthermore, we detected a stable trimolecular complex of PAK1, PIX and the paxillin kinase linker p95PKL. Taken together, these data show that PAK1 contained in this trimolecular complex is activated by a novel LAT- and Slp-76-independent pathway following TCR stimulation.
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Affiliation(s)
| | - Deborah Yablonski
- Howard Hughes Medical Institute, Department of Medicine, Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143-0414, USA,
Department of Pharmacology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, POB 9649 Bat Galim, Haifa 31096, Israel, Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609 and Institute of Neurology, University College London, London WC1N 1PJ, UK Corresponding author e-mail:
| | - Edward Manser
- Howard Hughes Medical Institute, Department of Medicine, Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143-0414, USA,
Department of Pharmacology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, POB 9649 Bat Galim, Haifa 31096, Israel, Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609 and Institute of Neurology, University College London, London WC1N 1PJ, UK Corresponding author e-mail:
| | - Louis Lim
- Howard Hughes Medical Institute, Department of Medicine, Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143-0414, USA,
Department of Pharmacology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, POB 9649 Bat Galim, Haifa 31096, Israel, Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609 and Institute of Neurology, University College London, London WC1N 1PJ, UK Corresponding author e-mail:
| | - Arthur Weiss
- Howard Hughes Medical Institute, Department of Medicine, Biomedical Sciences Graduate Program, University of California, San Francisco, CA 94143-0414, USA,
Department of Pharmacology, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, POB 9649 Bat Galim, Haifa 31096, Israel, Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609 and Institute of Neurology, University College London, London WC1N 1PJ, UK Corresponding author e-mail:
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McGinnis K, Ku GM, Fu J, Stern AM, Friedman PA. The five cysteine residues located in the active site region of bovine aspartyl (asparaginyl) beta-hydroxylase are not essential for catalysis. Biochim Biophys Acta 1998; 1387:454-6. [PMID: 9748662 DOI: 10.1016/s0167-4838(98)00130-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In previous chemical modification studies on bovine aspartyl (asparaginyl) beta-hydroxylase, cysteines were implicated as critical catalytic residues. Using site-directed mutagenesis, the five cysteine residues located in a highly conserved region of the enzyme identified as the active site were individually mutated to alanine. Substitutions at cysteine 637, 644, 656, 681, and 696 resulted in active mutant enzymes indicating that these residues are not required for catalysis.
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Affiliation(s)
- K McGinnis
- Merck Research Laboratories, West Point, PA 19486, USA
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McGinnis K, Ku GM, VanDusen WJ, Fu J, Garsky V, Stern AM, Friedman PA. Site-directed mutagenesis of residues in a conserved region of bovine aspartyl (asparaginyl) beta-hydroxylase: evidence that histidine 675 has a role in binding Fe2+. Biochemistry 1996; 35:3957-62. [PMID: 8672427 DOI: 10.1021/bi951520n] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The roles in catalysis of several residues in bovine aspartyl (asparaginyl) beta-hydroxylase that are located in a region of homology among alpha-ketoglutarate-dependent dioxygenases were investigated using site-directed mutagenesis. Previous studies have shown that when histidine 675, an invariant residue located in this highly conserved region, was mutated to an alanine residue, no enzymatic activity was detected. A more extensive site-directed mutagenesis study at position 675 has been undertaken to define the catalytic role of this essential residue. The partial hydroxylase activity observed with some amino acid replacements for histidine 675 correlates with the potential to coordinate metals and not with size, charge, or hydrophobic character. Furthermore, the increase in Km for Fe2+ observed with the H675D and H675E mutant enzymes can account for their partial activities relative to wild type. No significant changes in the Km for alpha-ketoglutarate (at saturating Fe2+) or Vmax were observed for these mutants. These results support the conclusion that histidine 675 is specifically involved in Fe2+ coordination. Further site-directed mutagenesis of other highly conserved residues in the vicinity of position 675 demonstrates the importance of this region of homology in catalysis for Asp (Asn) beta-hydroxylase and, by analogy, other alpha-ketoglutarate-dependent dioxygenases.
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Affiliation(s)
- K McGinnis
- Merck Research Laboratories, West Point, Pennsylvania 19486, USA
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