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Specific control of pancreatic endocrine β- and δ-cell mass by class IIa histone deacetylases HDAC4, HDAC5, and HDAC9.

Lenoir O, Flosseau K, Ma FX, Blondeau B, Mai A, Bassel-Duby R, Ravassard P, Olson EN, Haumaitre C, Scharfmann R - Diabetes (2011)

Bottom Line: Conversely, HDAC4 and HDAC5 overexpression showed a decreased pool of insulin-producing β-cells and somatostatin-producing δ-cells.We conclude that HDAC4, -5, and -9 are key regulators to control the pancreatic β/δ-cell lineage.These results highlight the epigenetic mechanisms underlying the regulation of endocrine cell development and suggest new strategies for β-cell differentiation-based therapies.

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Santé et de la Recherche Médicale, U845, Research Center Growth and Signalling, Paris Descartes University, Sorbonne Paris Cité, Necker Hospital, Paris, France.

ABSTRACT

Objective: Class IIa histone deacetylases (HDACs) belong to a large family of enzymes involved in protein deacetylation and play a role in regulating gene expression and cell differentiation. Previously, we showed that HDAC inhibitors modify the timing and determination of pancreatic cell fate. The aim of this study was to determine the role of class IIa HDACs in pancreas development.

Research design and methods: We took a genetic approach and analyzed the pancreatic phenotype of mice lacking HDAC4, -5, and -9. We also developed a novel method of lentiviral infection of pancreatic explants and performed gain-of-function experiments.

Results: We show that class IIa HDAC4, -5, and -9 have an unexpected restricted expression in the endocrine β- and δ-cells of the pancreas. Analyses of the pancreas of class IIa HDAC mutant mice revealed an increased pool of insulin-producing β-cells in Hdac5(-/-) and Hdac9(-/-) mice and an increased pool of somatostatin-producing δ-cells in Hdac4(-/-) and Hdac5(-/-) mice. Conversely, HDAC4 and HDAC5 overexpression showed a decreased pool of insulin-producing β-cells and somatostatin-producing δ-cells. Finally, treatment of pancreatic explants with the selective class IIa HDAC inhibitor MC1568 enhances expression of Pax4, a key factor required for proper β-and δ-cell differentiation and amplifies endocrine β- and δ-cells.

Conclusions: We conclude that HDAC4, -5, and -9 are key regulators to control the pancreatic β/δ-cell lineage. These results highlight the epigenetic mechanisms underlying the regulation of endocrine cell development and suggest new strategies for β-cell differentiation-based therapies.

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HDAC9 loss-of-function enhances β-cell mass. A: Immunohistological analyses of wild-type and Hdac9−/− pancreas at E18.5 and P7. β-Cells were detected with insulin (INS) staining (brown). B: Morphometric analysis of the β-cell surface by quantification of areas occupied by insulin-positive cells. β-Cell surfaces were normalized to wild-type (WT) values (100%). Data are shown as means ± SEM. At E18.5, we analyzed five WT and four Hdac9−/− pancreata. At P7, we analyzed four WT and three Hdac9−/− pancreata. *P < 0.05; ***P < 0.001. Scale bar, 100 μm. (A high-quality digital representation of this figure is available in the online issue.)
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Figure 7: HDAC9 loss-of-function enhances β-cell mass. A: Immunohistological analyses of wild-type and Hdac9−/− pancreas at E18.5 and P7. β-Cells were detected with insulin (INS) staining (brown). B: Morphometric analysis of the β-cell surface by quantification of areas occupied by insulin-positive cells. β-Cell surfaces were normalized to wild-type (WT) values (100%). Data are shown as means ± SEM. At E18.5, we analyzed five WT and four Hdac9−/− pancreata. At P7, we analyzed four WT and three Hdac9−/− pancreata. *P < 0.05; ***P < 0.001. Scale bar, 100 μm. (A high-quality digital representation of this figure is available in the online issue.)

Mentions: HDAC9 is expressed in skeletal muscle, heart, brain, lymphocytes, and erythrocytes (25,29–31), and mice lacking Hdac9 are hypersensitive to cardiac stress (9). There was no difference detected in the body weight or pancreatic weight between Hdac9−/− and wild-type mice (data not shown). We examined insulin-positive cells in Hdac9−/− mice, since we detected HDAC9 only in β-cells. We observed that at E18.5 and P7, β-cell mass was 1.38 ± 0.08 higher in Hdac9−/− mice than in wild-type mice (Fig. 7A and B). At E18.5, β-cell proliferation measured by Ki67 immunostaining did not differ between Hdac9−/− and wild-type pancreata (Supplementary Fig. 6C). No change in α-cell mass was observed (Supplementary Fig. 6A and B). Thus, deletion of HDAC9 in the pancreas enhances β-cell mass.


Specific control of pancreatic endocrine β- and δ-cell mass by class IIa histone deacetylases HDAC4, HDAC5, and HDAC9.

Lenoir O, Flosseau K, Ma FX, Blondeau B, Mai A, Bassel-Duby R, Ravassard P, Olson EN, Haumaitre C, Scharfmann R - Diabetes (2011)

HDAC9 loss-of-function enhances β-cell mass. A: Immunohistological analyses of wild-type and Hdac9−/− pancreas at E18.5 and P7. β-Cells were detected with insulin (INS) staining (brown). B: Morphometric analysis of the β-cell surface by quantification of areas occupied by insulin-positive cells. β-Cell surfaces were normalized to wild-type (WT) values (100%). Data are shown as means ± SEM. At E18.5, we analyzed five WT and four Hdac9−/− pancreata. At P7, we analyzed four WT and three Hdac9−/− pancreata. *P < 0.05; ***P < 0.001. Scale bar, 100 μm. (A high-quality digital representation of this figure is available in the online issue.)
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3198089&req=5

Figure 7: HDAC9 loss-of-function enhances β-cell mass. A: Immunohistological analyses of wild-type and Hdac9−/− pancreas at E18.5 and P7. β-Cells were detected with insulin (INS) staining (brown). B: Morphometric analysis of the β-cell surface by quantification of areas occupied by insulin-positive cells. β-Cell surfaces were normalized to wild-type (WT) values (100%). Data are shown as means ± SEM. At E18.5, we analyzed five WT and four Hdac9−/− pancreata. At P7, we analyzed four WT and three Hdac9−/− pancreata. *P < 0.05; ***P < 0.001. Scale bar, 100 μm. (A high-quality digital representation of this figure is available in the online issue.)
Mentions: HDAC9 is expressed in skeletal muscle, heart, brain, lymphocytes, and erythrocytes (25,29–31), and mice lacking Hdac9 are hypersensitive to cardiac stress (9). There was no difference detected in the body weight or pancreatic weight between Hdac9−/− and wild-type mice (data not shown). We examined insulin-positive cells in Hdac9−/− mice, since we detected HDAC9 only in β-cells. We observed that at E18.5 and P7, β-cell mass was 1.38 ± 0.08 higher in Hdac9−/− mice than in wild-type mice (Fig. 7A and B). At E18.5, β-cell proliferation measured by Ki67 immunostaining did not differ between Hdac9−/− and wild-type pancreata (Supplementary Fig. 6C). No change in α-cell mass was observed (Supplementary Fig. 6A and B). Thus, deletion of HDAC9 in the pancreas enhances β-cell mass.

Bottom Line: Conversely, HDAC4 and HDAC5 overexpression showed a decreased pool of insulin-producing β-cells and somatostatin-producing δ-cells.We conclude that HDAC4, -5, and -9 are key regulators to control the pancreatic β/δ-cell lineage.These results highlight the epigenetic mechanisms underlying the regulation of endocrine cell development and suggest new strategies for β-cell differentiation-based therapies.

View Article: PubMed Central - PubMed

Affiliation: Institut National de la Santé et de la Recherche Médicale, U845, Research Center Growth and Signalling, Paris Descartes University, Sorbonne Paris Cité, Necker Hospital, Paris, France.

ABSTRACT

Objective: Class IIa histone deacetylases (HDACs) belong to a large family of enzymes involved in protein deacetylation and play a role in regulating gene expression and cell differentiation. Previously, we showed that HDAC inhibitors modify the timing and determination of pancreatic cell fate. The aim of this study was to determine the role of class IIa HDACs in pancreas development.

Research design and methods: We took a genetic approach and analyzed the pancreatic phenotype of mice lacking HDAC4, -5, and -9. We also developed a novel method of lentiviral infection of pancreatic explants and performed gain-of-function experiments.

Results: We show that class IIa HDAC4, -5, and -9 have an unexpected restricted expression in the endocrine β- and δ-cells of the pancreas. Analyses of the pancreas of class IIa HDAC mutant mice revealed an increased pool of insulin-producing β-cells in Hdac5(-/-) and Hdac9(-/-) mice and an increased pool of somatostatin-producing δ-cells in Hdac4(-/-) and Hdac5(-/-) mice. Conversely, HDAC4 and HDAC5 overexpression showed a decreased pool of insulin-producing β-cells and somatostatin-producing δ-cells. Finally, treatment of pancreatic explants with the selective class IIa HDAC inhibitor MC1568 enhances expression of Pax4, a key factor required for proper β-and δ-cell differentiation and amplifies endocrine β- and δ-cells.

Conclusions: We conclude that HDAC4, -5, and -9 are key regulators to control the pancreatic β/δ-cell lineage. These results highlight the epigenetic mechanisms underlying the regulation of endocrine cell development and suggest new strategies for β-cell differentiation-based therapies.

Show MeSH
Related in: MedlinePlus