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Toledo PL, Torkko JM, Müller A, Wegbrod C, Sönmez A, Solimena M, Ermácora MR. ICA512 RESP18 homology domain is a protein-condensing factor and insulin fibrillation inhibitor. J Biol Chem 2019; 294:8564-8576. [PMID: 30979722 DOI: 10.1074/jbc.ra119.007607] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/09/2019] [Indexed: 12/19/2022] Open
Abstract
Type 1 diabetes islet cell autoantigen 512 (ICA512/IA-2) is a tyrosine phosphatase-like intrinsic membrane protein involved in the biogenesis and turnover of insulin secretory granules (SGs) in pancreatic islet β-cells. Whereas its membrane-proximal and cytoplasmic domains have been functionally and structurally characterized, the role of the ICA512 N-terminal segment named "regulated endocrine-specific protein 18 homology domain" (RESP18HD), which encompasses residues 35-131, remains largely unknown. Here, we show that ICA512 RESP18HD residues 91-131 encode for an intrinsically disordered region (IDR), which in vitro acts as a condensing factor for the reversible aggregation of insulin and other β-cell proteins in a pH and Zn2+-regulated fashion. At variance with what has been shown for other granule cargoes with aggregating properties, the condensing activity of ICA512 RESP18HD is displayed at a pH close to neutral, i.e. in the pH range found in the early secretory pathway, whereas it is resolved at acidic pH and Zn2+ concentrations resembling those present in mature SGs. Moreover, we show that ICA512 RESP18HD residues 35-90, preceding the IDR, inhibit insulin fibrillation in vitro Finally, we found that glucose-stimulated secretion of RESP18HD upon exocytosis of SGs from insulinoma INS-1 cells is associated with cleavage of its IDR, conceivably to prevent its aggregation upon exposure to neutral pH in the extracellular milieu. Taken together, these findings point to ICA512 RESP18HD being a condensing factor for protein sorting and granulogenesis early in the secretory pathway and for prevention of amyloidogenesis.
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Affiliation(s)
- Pamela L Toledo
- Grupo de Biología Estructural y Biotecnología, Universidad Nacional de Quilmes, 1876 Bernal, Buenos Aires, Argentina; IMBICE, CONICET-CIC-Universidad Nacional de La Plata, B1906APO La Plata, Buenos Aires, Argentina
| | - Juha M Torkko
- Grupo de Biología Estructural y Biotecnología, Universidad Nacional de Quilmes, 1876 Bernal, Buenos Aires, Argentina; IMBICE, CONICET-CIC-Universidad Nacional de La Plata, B1906APO La Plata, Buenos Aires, Argentina; Department of Molecular Diabetology, University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85764 Neuherberg, Germany
| | - Andreas Müller
- Department of Molecular Diabetology, University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85764 Neuherberg, Germany
| | - Carolin Wegbrod
- Department of Molecular Diabetology, University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85764 Neuherberg, Germany
| | - Anke Sönmez
- Department of Molecular Diabetology, University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85764 Neuherberg, Germany
| | - Michele Solimena
- Department of Molecular Diabetology, University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; Paul Langerhans Institute Dresden of the Helmholtz Center Munich at the University Hospital and Faculty of Medicine, TU Dresden, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), 85764 Neuherberg, Germany; Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany.
| | - Mario R Ermácora
- Grupo de Biología Estructural y Biotecnología, Universidad Nacional de Quilmes, 1876 Bernal, Buenos Aires, Argentina; IMBICE, CONICET-CIC-Universidad Nacional de La Plata, B1906APO La Plata, Buenos Aires, Argentina.
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2
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Sanchez-Parra C, Jacovetti C, Dumortier O, Lee K, Peyot ML, Guay C, Prentki M, Laybutt DR, Van Obberghen E, Regazzi R. Contribution of the Long Noncoding RNA H19 to β-Cell Mass Expansion in Neonatal and Adult Rodents. Diabetes 2018; 67:2254-2267. [PMID: 30115652 DOI: 10.2337/db18-0201] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 08/03/2018] [Indexed: 11/13/2022]
Abstract
Pancreatic β-cell expansion throughout the neonatal period is essential to generate the appropriate mass of insulin-secreting cells required to maintain blood glucose homeostasis later in life. Hence, defects in this process can predispose to diabetes development during adulthood. Global profiling of transcripts in pancreatic islets of newborn and adult rats revealed that the transcription factor E2F1 controls expression of the long noncoding RNA H19, which is profoundly downregulated during the postnatal period. H19 silencing decreased β-cell expansion in newborns, whereas its re-expression promoted proliferation of β-cells in adults via a mechanism involving the microRNA let-7 and the activation of Akt. The offspring of rats fed a low-protein diet during gestation and lactation display a small β-cell mass and an increased risk of developing diabetes during adulthood. We found that the islets of newborn rats born to dams fed a low-protein diet express lower levels of H19 than those born to dams that did not eat a low-protein diet. Moreover, we observed that H19 expression increases in islets of obese mice under conditions of increased insulin demand. Our data suggest that the long noncoding RNA H19 plays an important role in postnatal β-cell mass expansion in rats and contributes to the mechanisms compensating for insulin resistance in obesity.
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Affiliation(s)
- Clara Sanchez-Parra
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Cécile Jacovetti
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Olivier Dumortier
- University Côte d'Azur, INSERM, CNRS, Institute for Research on Cancer and Aging, Nice, France
| | - Kailun Lee
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Marie-Line Peyot
- Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier Universitaire de Montréal, Montréal, Québec, Canada
| | - Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Marc Prentki
- Montreal Diabetes Research Center and Centre de Recherche du Centre Hospitalier Universitaire de Montréal, Montréal, Québec, Canada
| | - D Ross Laybutt
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Sydney, New South Wales, Australia
| | - Emmanuel Van Obberghen
- University Côte d'Azur, Centre Hospitalier Universitaire, INSERM, CNRS, Institute for Research on Cancer and Aging, Nice, France
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
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3
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Different developmental histories of beta-cells generate functional and proliferative heterogeneity during islet growth. Nat Commun 2017; 8:664. [PMID: 28939870 PMCID: PMC5610262 DOI: 10.1038/s41467-017-00461-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 06/30/2017] [Indexed: 12/11/2022] Open
Abstract
The proliferative and functional heterogeneity among seemingly uniform cells is a universal phenomenon. Identifying the underlying factors requires single-cell analysis of function and proliferation. Here we show that the pancreatic beta-cells in zebrafish exhibit different growth-promoting and functional properties, which in part reflect differences in the time elapsed since birth of the cells. Calcium imaging shows that the beta-cells in the embryonic islet become functional during early zebrafish development. At later stages, younger beta-cells join the islet following differentiation from post-embryonic progenitors. Notably, the older and younger beta-cells occupy different regions within the islet, which generates topological asymmetries in glucose responsiveness and proliferation. Specifically, the older beta-cells exhibit robust glucose responsiveness, whereas younger beta-cells are more proliferative but less functional. As the islet approaches its mature state, heterogeneity diminishes and beta-cells synchronize function and proliferation. Our work illustrates a dynamic model of heterogeneity based on evolving proliferative and functional beta-cell states. Βeta-cells have recently been shown to be heterogeneous with regard to morphology and function. Here, the authors show that β-cells in zebrafish switch from proliferative to functional states with increasing time since β-cell birth, leading to functional and proliferative heterogeneity.
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4
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Paul PK, Rabaglia ME, Wang CY, Stapleton DS, Leng N, Kendziorski C, Lewis PW, Keller MP, Attie AD. Histone chaperone ASF1B promotes human β-cell proliferation via recruitment of histone H3.3. Cell Cycle 2016; 15:3191-3202. [PMID: 27753532 DOI: 10.1080/15384101.2016.1241914] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Anti-silencing function 1 (ASF1) is a histone H3-H4 chaperone involved in DNA replication and repair, and transcriptional regulation. Here, we identify ASF1B, the mammalian paralog to ASF1, as a proliferation-inducing histone chaperone in human β-cells. Overexpression of ASF1B led to distinct transcriptional signatures consistent with increased cellular proliferation and reduced cellular death. Using multiple methods of monitoring proliferation and mitotic progression, we show that overexpression of ASF1B is sufficient to induce human β-cell proliferation. Co-expression of histone H3.3 further augmented β-cell proliferation, whereas suppression of endogenous H3.3 attenuated the stimulatory effect of ASF1B. Using the histone binding-deficient mutant of ASF1B (V94R), we show that histone binding to ASF1B is required for the induction of β-cell proliferation. In contrast to H3.3, overexpression of histone H3 variants H3.1 and H3.2 did not have an impact on ASF1B-mediated induction of proliferation. Our findings reveal a novel role of ASF1B in human β-cell replication and show that ASF1B and histone H3.3A synergistically stimulate human β-cell proliferation.
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Affiliation(s)
- Pradyut K Paul
- a Department of Biochemistry , University of Wisconsin , Madison , WI , USA
| | - Mary E Rabaglia
- a Department of Biochemistry , University of Wisconsin , Madison , WI , USA
| | - Chen-Yu Wang
- a Department of Biochemistry , University of Wisconsin , Madison , WI , USA
| | - Donald S Stapleton
- a Department of Biochemistry , University of Wisconsin , Madison , WI , USA
| | - Ning Leng
- b Department of Statistics , University of Wisconsin , Madison , WI , USA
| | - Christina Kendziorski
- c Department of Biostatistics and Medical Informatics , University of Wisconsin , Madison , WI , USA
| | - Peter W Lewis
- d Department of Biomolecular Chemistry , University of Wisconsin , Madison , WI , USA
| | - Mark P Keller
- a Department of Biochemistry , University of Wisconsin , Madison , WI , USA
| | - Alan D Attie
- a Department of Biochemistry , University of Wisconsin , Madison , WI , USA
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5
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Golson ML, Dunn JC, Maulis MF, Dadi PK, Osipovich AB, Magnuson MA, Jacobson DA, Gannon M. Activation of FoxM1 Revitalizes the Replicative Potential of Aged β-Cells in Male Mice and Enhances Insulin Secretion. Diabetes 2015; 64:3829-38. [PMID: 26251404 PMCID: PMC4613976 DOI: 10.2337/db15-0465] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 07/26/2015] [Indexed: 12/11/2022]
Abstract
Type 2 diabetes incidence increases with age, while β-cell replication declines. The transcription factor FoxM1 is required for β-cell replication in various situations, and its expression declines with age. We hypothesized that increased FoxM1 activity in aged β-cells would rejuvenate proliferation. Induction of an activated form of FoxM1 was sufficient to increase β-cell mass and proliferation in 12-month-old male mice after just 2 weeks. Unexpectedly, at 2 months of age, induction of activated FoxM1 in male mice improved glucose homeostasis with unchanged β-cell mass. Cells expressing activated FoxM1 demonstrated enhanced glucose-stimulated Ca2+ influx, which resulted in improved glucose tolerance through enhanced β-cell function. Conversely, our laboratory has previously demonstrated that mice lacking FoxM1 in the pancreas display glucose intolerance or diabetes with only a 60% reduction in β-cell mass, suggesting that the loss of FoxM1 is detrimental to β-cell function. Ex vivo insulin secretion was therefore examined in size-matched islets from young mice lacking FoxM1 in β-cells. Foxm1-deficient islets indeed displayed reduced insulin secretion. Our studies reveal that activated FoxM1 increases β-cell replication while simultaneously enhancing insulin secretion and improving glucose homeostasis, making FoxM1 an attractive therapeutic target for diabetes.
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Affiliation(s)
- Maria L Golson
- VA Tennessee Valley Healthcare System, Nashville, TN Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN
| | - Jennifer C Dunn
- VA Tennessee Valley Healthcare System, Nashville, TN Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN
| | - Matthew F Maulis
- VA Tennessee Valley Healthcare System, Nashville, TN Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Anna B Osipovich
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN Vanderbilt Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, TN
| | - Mark A Magnuson
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN Vanderbilt Center for Stem Cell Biology, Vanderbilt University Medical Center, Nashville, TN
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
| | - Maureen Gannon
- VA Tennessee Valley Healthcare System, Nashville, TN Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN
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6
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Leibiger B, Moede T, Paschen M, Yunn NO, Lim JH, Ryu SH, Pereira T, Berggren PO, Leibiger IB. PI3K-C2α Knockdown Results in Rerouting of Insulin Signaling and Pancreatic Beta Cell Proliferation. Cell Rep 2015; 13:15-22. [PMID: 26387957 DOI: 10.1016/j.celrep.2015.08.058] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 07/20/2015] [Accepted: 08/20/2015] [Indexed: 11/26/2022] Open
Abstract
Insulin resistance is a syndrome that affects multiple insulin target tissues, each having different biological functions regulated by insulin. A remaining question is to mechanistically explain how an insulin target cell/tissue can be insulin resistant in one biological function and insulin sensitive in another at the same time. Here, we provide evidence that in pancreatic β cells, knockdown of PI3K-C2α expression results in rerouting of the insulin signal from insulin receptor (IR)-B/PI3K-C2α/PKB-mediated metabolic signaling to IR-B/Shc/ERK-mediated mitogenic signaling, which allows the β cell to switch from a highly glucose-responsive, differentiated state to a proliferative state. Our data suggest the existence of IR-cascade-selective insulin resistance, which allows rerouting of the insulin signal within the same target cell. Hence, factors involved in the rerouting of the insulin signal represent tentative therapeutic targets in the treatment of insulin resistance.
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Affiliation(s)
- Barbara Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Tilo Moede
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Meike Paschen
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Na-Oh Yunn
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Jong Hoon Lim
- Aptamer Initiative Program, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Sung Ho Ryu
- School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea; Aptamer Initiative Program, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea; Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea
| | - Teresa Pereira
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden; Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 637 553, Singapore.
| | - Ingo B Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, 171 76 Stockholm, Sweden.
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7
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Assefa Z, Lavens A, Steyaert C, Stangé G, Martens GA, Ling Z, Hellemans K, Pipeleers D. Glucose regulates rat beta cell number through age-dependent effects on beta cell survival and proliferation. PLoS One 2014; 9:e85174. [PMID: 24416358 PMCID: PMC3887027 DOI: 10.1371/journal.pone.0085174] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Accepted: 11/24/2013] [Indexed: 11/22/2022] Open
Abstract
Background Glucose effects on beta cell survival and DNA-synthesis suggest a role as regulator of beta cell mass but data on beta cell numbers are lacking. We examined outcome of these influences on the number of beta cells isolated at different growth stages in their population. Methods Beta cells from neonatal, young-adult and old rats were cultured serum-free for 15 days. Their number was counted by automated whole-well imaging distinguishing influences on cell survival and on proliferative activity. Results Elevated glucose (10–20 versus 5 mmol/l) increased the number of living beta cells from 8-week rats to 30%, following a time- and concentration-dependent recruitment of quiescent cells into DNA-synthesis; a glucokinase-activator lowered the threshold but did not raise total numbers of glucose-recruitable cells. No glucose-induced increase occurred in beta cells from 40-week rats. Neonatal beta cells doubled in number at 5 mmol/l involving a larger activated fraction that did not increase at higher concentrations; however, their higher susceptibility to glucose toxicity at 20 mmol/l resulted in 20% lower living cell numbers than at start. None of the age groups exhibited a repetitively proliferating subpopulation. Conclusions Chronically elevated glucose levels increased the number of beta cells from young-adult but not from old rats; they interfered with expansion of neonatal beta cells and reduced their number. These effects are attributed to age-dependent differences in basal and glucose-induced proliferative activity and in cellular susceptibility to glucose toxicity. They also reflect age-dependent variations in the functional heterogeneity of the rat beta cell population.
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Affiliation(s)
- Zerihun Assefa
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
| | - Astrid Lavens
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
| | - Christophe Steyaert
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
| | - Geert Stangé
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
| | - Geert A Martens
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
| | - Zhidong Ling
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
| | - Karine Hellemans
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
| | - Daniel Pipeleers
- Diabetes Pathology and Therapy Unit, Diabetes Research Center and Center for Beta Cell Therapy, Brussels Free University-VUB, Brussels, Belgium
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8
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Hamze Z, Vercherat C, Bernigaud-Lacheretz A, Bazzi W, Bonnavion R, Lu J, Calender A, Pouponnot C, Bertolino P, Roche C, Stein R, Scoazec JY, Zhang CX, Cordier-Bussat M. Altered MENIN expression disrupts the MAFA differentiation pathway in insulinoma. Endocr Relat Cancer 2013; 20:833-48. [PMID: 24157940 PMCID: PMC3841063 DOI: 10.1530/erc-13-0164] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The protein MENIN is the product of the multiple endocrine neoplasia type I (MEN1) gene. Altered MENIN expression is one of the few events that are clearly associated with foregut neuroendocrine tumours (NETs), classical oncogenes or tumour suppressors being not involved. One of the current challenges is to understand how alteration of MENIN expression contributes to the development of these tumours. We hypothesised that MENIN might regulate factors maintaining endocrine-differentiated functions. We chose the insulinoma model, a paradigmatic example of well-differentiated pancreatic NETs, to study whether MENIN interferes with the expression of v-MAF musculoaponeurotic fibrosarcoma oncogene homologue A (MAFA), a master glucose-dependent transcription factor in differentiated β-cells. Immunohistochemical analysis of a series of human insulinomas revealed a correlated decrease in both MENIN and MAFA. Decreased MAFA expression resulting from targeted Men1 ablation was also consistently observed in mouse insulinomas. In vitro analyses using insulinoma cell lines showed that MENIN regulated MAFA protein and mRNA levels, and bound to Mafa promoter sequences. MENIN knockdown concomitantly decreased mRNA expression of both Mafa and β-cell differentiation markers (Ins1/2, Gck, Slc2a2 and Pdx1) and, in parallel, increased the proliferation rate of tumours as measured by bromodeoxyuridine incorporation. Interestingly, MAFA knockdown alone also increased proliferation rate but did not affect the expression of candidate proliferation genes regulated by MENIN. Finally, MENIN variants with missense mutations detected in patients with MEN1 lost the WT MENIN properties to regulate MAFA. Together, our findings unveil a previously unsuspected MENIN/MAFA connection regarding control of the β-cell differentiation/proliferation balance, which could contribute to tumorigenesis.
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MESH Headings
- Adult
- Aged
- Animals
- Apoptosis
- Blotting, Western
- Carcinoma, Neuroendocrine/genetics
- Carcinoma, Neuroendocrine/metabolism
- Carcinoma, Neuroendocrine/pathology
- Cell Differentiation
- Cell Proliferation
- Chromatin Immunoprecipitation
- Female
- Glucose/pharmacology
- Humans
- Immunoenzyme Techniques
- Insulin-Secreting Cells/metabolism
- Insulin-Secreting Cells/pathology
- Insulinoma/genetics
- Insulinoma/metabolism
- Insulinoma/pathology
- Maf Transcription Factors, Large/antagonists & inhibitors
- Maf Transcription Factors, Large/genetics
- Maf Transcription Factors, Large/metabolism
- Male
- Mice
- Mice, Knockout
- Middle Aged
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/metabolism
- Pancreatic Neoplasms/pathology
- Proto-Oncogene Proteins/antagonists & inhibitors
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins/physiology
- RNA, Messenger/genetics
- RNA, Small Interfering/genetics
- Rats
- Real-Time Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Tumor Cells, Cultured
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Affiliation(s)
- Z Hamze
- INSERM U1052/CNRS UMR5286/Université de Lyon, Lyon1 UMR-S1052, Cancer Research Center of Lyon, Lyon F-69008, France Service de Génétique Moléculaire et Clinique, Hospices Civils de Lyon, Hôpital Edouard Herriot, Lyon F-69437, France UMR 3347/CNRS, U1021/INSERM, Institut Curie, Orsay F-91405, France Service Central d'Anatomie et Cytologie Pathologiques, Hospices Civils de Lyon, Hôpital Edouard Herriot, Lyon F-69437, France Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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9
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Aly H, Rohatgi N, Marshall CA, Grossenheider TC, Miyoshi H, Stappenbeck TS, Matkovich SJ, McDaniel ML. A novel strategy to increase the proliferative potential of adult human β-cells while maintaining their differentiated phenotype. PLoS One 2013; 8:e66131. [PMID: 23776620 PMCID: PMC3680388 DOI: 10.1371/journal.pone.0066131] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 05/01/2013] [Indexed: 12/13/2022] Open
Abstract
Our previous studies demonstrated that Wnt/GSK-3/β-catenin and mTOR signaling are necessary to stimulate proliferative processes in adult human β-cells. Direct inhibition of GSK-3, that engages Wnt signaling downstream of the Wnt receptor, increases β-catenin nuclear translocation and β-cell proliferation but results in lower insulin content. Our current goal was to engage canonical and non-canonical Wnt signaling at the receptor level to significantly increase human β-cell proliferation while maintaining a β-cell phenotype in intact islets. We adopted a system that utilized conditioned medium from L cells that expressed Wnt3a, R-spondin-3 and Noggin (L-WRN conditioned medium). In addition we used a ROCK inhibitor (Y-27632) and SB-431542 (that results in RhoA inhibition) in these cultures. Treatment of intact human islets with L-WRN conditioned medium plus inhibitors significantly increased DNA synthesis ∼6 fold in a rapamycin-sensitive manner. Moreover, this treatment strikingly increased human β-cell proliferation ∼20 fold above glucose alone. Only the combination of L-WRN conditioned medium with RhoA/ROCK inhibitors resulted in substantial proliferation. Transcriptome-wide gene expression profiling demonstrated that L-WRN medium provoked robust changes in several signaling families, including enhanced β-catenin-mediated and β-cell-specific gene expression. This treatment also increased expression of Nr4a2 and Irs2 and resulted in phosphorylation of Akt. Importantly, glucose-stimulated insulin secretion and content were not downregulated by L-WRN medium treatment. Our data demonstrate that engaging Wnt signaling at the receptor level by this method leads to necessary crosstalk between multiple signaling pathways including activation of Akt, mTOR, Wnt/β-catenin, PKA/CREB, and inhibition of RhoA/ROCK that substantially increase human β-cell proliferation while maintaining the β-cell phenotype.
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Affiliation(s)
- Haytham Aly
- Department of Pathology and Immunology Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Nidhi Rohatgi
- Department of Pathology and Immunology Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Connie A. Marshall
- Department of Pathology and Immunology Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Tiffani C. Grossenheider
- Center for Pharmacogenomics, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Hiroyuki Miyoshi
- Department of Pathology and Immunology Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Thaddeus S. Stappenbeck
- Department of Pathology and Immunology Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Scot J. Matkovich
- Center for Pharmacogenomics, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Michael L. McDaniel
- Department of Pathology and Immunology Washington University in St. Louis, St. Louis, Missouri, United States of America
- * E-mail:
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Rohatgi N, Aly H, Marshall CA, McDonald WG, Kletzien RF, Colca JR, McDaniel ML. Novel insulin sensitizer modulates nutrient sensing pathways and maintains β-cell phenotype in human islets. PLoS One 2013; 8:e62012. [PMID: 23650507 PMCID: PMC3641131 DOI: 10.1371/journal.pone.0062012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 03/17/2013] [Indexed: 02/04/2023] Open
Abstract
Major bottlenecks in the expansion of human β-cell mass are limited proliferation, loss of β-cell phenotype, and increased apoptosis. In our previous studies, activation of Wnt and mTOR signaling significantly enhanced human β-cell proliferation. However, isolated human islets displayed insulin signaling pathway resistance, due in part to chronic activation of mTOR/S6K1 signaling that results in negative feedback of the insulin signaling pathway and a loss of Akt phosphorylation and insulin content. We evaluated the effects of a new generation insulin sensitizer, MSDC-0160, on restoring insulin/IGF-1 sensitivity and insulin content in human β-cells. This novel TZD has low affinity for binding and activation of PPARγ and has insulin-sensitizing effects in mouse models of diabetes and ability to lower glucose in Phase 2 clinical trials. MSDC-0160 treatment of human islets increased AMPK activity and reduced mTOR activity. This was associated with the restoration of IGF-1-induced phosphorylation of Akt, GSK-3, and increased protein expression of Pdx1. Furthermore, MSDC-0160 in combination with IGF-1 and 8 mM glucose increased β-cell specific gene expression of insulin, pdx1, nkx6.1, and nkx2.2, and maintained insulin content without altering glucose-stimulated insulin secretion. Human islets were unable to simultaneously promote DNA synthesis and maintain the β-cell phenotype. Lithium-induced GSK-3 inhibition that promotes DNA synthesis blocked the ability of MSDC-0160 to maintain the β-cell phenotype. Conversely, MSDC-0160 prevented an increase in DNA synthesis by blocking β-catenin nuclear translocation. Due to the counteracting pathways involved in these processes, we employed a sequential ex vivo strategy to first induce human islet DNA synthesis, followed by MSDC-0160 to promote the β-cell phenotype and insulin content. This new generation PPARγ sparing insulin sensitizer may provide an initial tool for relieving inherent human islet insulin signaling pathway resistance that is necessary to preserve the β-cell phenotype during β-cell expansion for the treatment of diabetes.
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Affiliation(s)
- Nidhi Rohatgi
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Haytham Aly
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Connie A. Marshall
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - William G. McDonald
- Metabolic Solutions Development Company, Kalamazoo, Michigan, United States of America
| | - Rolf F. Kletzien
- Metabolic Solutions Development Company, Kalamazoo, Michigan, United States of America
| | - Jerry R. Colca
- Metabolic Solutions Development Company, Kalamazoo, Michigan, United States of America
| | - Michael L. McDaniel
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, Missouri, United States of America
- * E-mail:
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Abstract
Peptide hormones are powerful regulators of various biological processes. To guarantee continuous availability and function, peptide hormone secretion must be tightly coupled to its biosynthesis. A simple but efficient way to provide such regulation is through an autocrine feedback mechanism in which the secreted hormone is "sensed" by its respective receptor and initiates synthesis at the level of transcription and/or translation. Such a secretion-biosynthesis coupling has been demonstrated for insulin; however, because of insulin's unique role as the sole blood glucose-decreasing peptide hormone, this coupling is considered an exception rather than a more generally used mechanism. Here we provide evidence of a secretion-biosynthesis coupling for glucagon, one of several peptide hormones that increase blood glucose levels. We show that glucagon, secreted by the pancreatic α cell, up-regulates the expression of its own gene by signaling through the glucagon receptor, PKC, and PKA, supporting the more general applicability of an autocrine feedback mechanism in regulation of peptide hormone synthesis.
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Turban S, Liu X, Ramage L, Webster SP, Walker BR, Dunbar DR, Mullins JJ, Seckl JR, Morton NM. Optimal elevation of β-cell 11β-hydroxysteroid dehydrogenase type 1 is a compensatory mechanism that prevents high-fat diet-induced β-cell failure. Diabetes 2012; 61:642-52. [PMID: 22315313 PMCID: PMC3282808 DOI: 10.2337/db11-1054] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Type 2 diabetes ultimately results from pancreatic β-cell failure. Abnormally elevated intracellular regeneration of glucocorticoids by the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in fat or liver may underlie pathophysiological aspects of the metabolic syndrome. Elevated 11β-HSD1 is also found in pancreatic islets of obese/diabetic rodents and is hypothesized to suppress insulin secretion and promote diabetes. To define the direct impact of elevated pancreatic β-cell 11β-HSD1 on insulin secretion, we generated β-cell-specific, 11β-HSD1-overexpressing (MIP-HSD1) mice on a strain background prone to β-cell failure. Unexpectedly, MIP-HSD1(tg/+) mice exhibited a reversal of high fat-induced β-cell failure through augmentation of the number and intrinsic function of small islets in association with induction of heat shock, protein kinase A, and extracellular signal-related kinase and p21 signaling pathways. 11β-HSD1(-/-) mice showed mild β-cell impairment that was offset by improved glucose tolerance. The benefit of higher β-cell 11β-HSD1 exhibited a threshold because homozygous MIP-HSD1(tg/tg) mice and diabetic Lep(db/db) mice with markedly elevated β-cell 11β-HSD1 levels had impaired basal β-cell function. Optimal elevation of β-cell 11β-HSD1 represents a novel biological mechanism supporting compensatory insulin hypersecretion rather than exacerbating metabolic disease. These findings have immediate significance for current therapeutic strategies for type 2 diabetes.
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Affiliation(s)
- Sophie Turban
- Molecular Metabolism Group, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - Xiaoxia Liu
- Molecular Metabolism Group, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - Lynne Ramage
- Molecular Metabolism Group, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - Scott P. Webster
- Endocrinology Unit, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - Brian R. Walker
- Endocrinology Unit, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - Donald R. Dunbar
- Bioinformatics Core, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - John J. Mullins
- Molecular Physiology, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - Jonathan R. Seckl
- Endocrinology Unit, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
| | - Nicholas M. Morton
- Molecular Metabolism Group, University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, U.K
- Corresponding author: Nicholas M. Morton,
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Rohatgi N, Remedi MS, Kwon G, Pappan KL, Marshall CA, McDaniel ML. Therapeutic Strategies to Increase Human β-Cell Growth and Proliferation by Regulating mTOR and GSK-3/β-Catenin Pathways. ACTA ACUST UNITED AC 2010; 4. [PMID: 24339841 DOI: 10.2174/1874216501004010040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This perspective delineates approaches to develop therapeutic strategies to stimulate the proliferative potential of adult human β-cells in vitro. Previous findings demonstrated that nutrients, through regulation of mTOR signaling, promote regenerative processes including DNA synthesis, cell cycle progression and β-cell proliferation in rodent islets but rarely in human islets. Recently, we discovered that regulation of the Wnt/GSK-3/β-catenin pathway by directly inhibiting GSK-3 with pharmacologic agents, in combination with nutrient activation of mTOR, was required to increase growth and proliferation in human islets. Studies also revealed that nuclear translocation of β-catenin in response to GSK-3 inhibition regulated these processes and was rapamycin sensitive, indicating a role for mTOR. Human islets displayed a high level of insulin resistance consistent with the inability of exogenous insulin to activate Akt and engage the Wnt pathway by GSK-3 inhibition. This insulin resistance in human islets is not present in rodent islets and may explain the differential requirement in human islets to inhibit GSK-3 to enhance these regenerative processes. Human islets exhibited normal insulin secretion but a loss of insulin content, which was independent of all treatment conditions. The loss of insulin content may be related to insulin resistance, the isolation process or culture conditions. In this perspective, we provide strategies to enhance the proliferative capacity of adult human β-cells and highlight important differences between human and rodent islets: the lack of a nutrient response, requirement for direct GSK-3 inhibition, insulin resistance and loss of insulin content that emphasize the physiological significance of conducting studies in human islets.
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Affiliation(s)
- Nidhi Rohatgi
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, Missouri, USA
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