1. MiR-132 controls pancreatic beta cell proliferation and survival through Pten/Akt/Foxo3 signaling
- Author
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Johanna McChord, Katharina Ganss, Christian Krautz, Sebastian Hempel, Klaus-Peter Knoch, Michele Solimena, Robert Grützmann, Philippe Ravassard, Kamal Chowdhury, Jürgen Weitz, Stephan Kersting, Christian Pilarsky, Hassan Mziaut, Steffen Wolk, Georg Henniger, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Technische Universität Dresden = Dresden University of Technology (TU Dresden), Max-Planck-Institut für Biophysikalische Chemie - Max Planck Institute for Biophysical Chemistry [Göttingen], Max-Planck-Gesellschaft, Institut du Cerveau et de la Moëlle Epinière = Brain and Spine Institute (ICM), Institut National de la Santé et de la Recherche Médicale (INSERM)-CHU Pitié-Salpêtrière [AP-HP], Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), and Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG)
- Subjects
Male ,0301 basic medicine ,Pten, phosphatase and tensin homolog ,Pi3k, phosphatidylinositol-4,5-bisphosphate 3-kinase ,Apoptosis ,[SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,miR-132, microRNA 132 ,miR-132 ,Creb, cAMP response element-binding protein ,BrdU, bromodeoxyuridine ,Mice ,0302 clinical medicine ,Insulin-Secreting Cells ,miRNA, microRNA ,Raf, rapidly accelerated fibrosarcoma ,Cells, Cultured ,Mice, Knockout ,Gene knockdown ,Forkhead Box Protein O3 ,FOXO3 ,Original Article ,β cell regeneration ,Beta cell ,Signal Transduction ,lcsh:Internal medicine ,Cell Survival ,T2D, type 2 diabetes ,030209 endocrinology & metabolism ,Biology ,Fgfr3, fibroblast growth factor receptor 3 ,GSIS, glucose-stimulated insulin secretion ,03 medical and health sciences ,RT-PCR, reverse transcription polymerase chain reaction ,Pancreatectomy ,Nras, neuroblastoma RAS viral oncogene homolog ,Downregulation and upregulation ,Pten/Akt/Foxo3a ,[SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Genomics [q-bio.GN] ,microRNA ,Animals ,Humans ,PTEN ,Gnb, G protein subunit beta ,lcsh:RC31-1245 ,Molecular Biology ,Protein kinase B ,Gnb1, G protein subunit beta 1 ,IPA, Ingenuity Pathway Analysis ,Cell Proliferation ,Mir-132 ,Beta Cell Regeneration ,Pten/akt/foxo3a ,pHH3, phosphohistone H3 ,Mapk1, mitogen-activated protein kinase 1 ,PTEN Phosphohydrolase ,Cell Biology ,LCM, laser capture microscopy ,Mice, Inbred C57BL ,MicroRNAs ,HEK293 Cells ,030104 developmental biology ,Ras, rat sarcoma ,Pik3r1, phosphoinositide-3 kinase regulatory subunit 1 ,Akt, protein kinase B ,Cancer research ,biology.protein ,Foxo3a, Forkhead box O3a ,Sos1, Son of Sevenless homolog 1 ,Proto-Oncogene Proteins c-akt - Abstract
Objective MicroRNAs (miRNAs) play an integral role in maintaining beta cell function and identity. Deciphering their targets and precise role, however, remains challenging. In this study, we aimed to identify miRNAs and their downstream targets involved in the regeneration of islet beta cells following partial pancreatectomy in mice. Methods RNA from laser capture microdissected (LCM) islets of partially pancreatectomized and sham-operated mice were profiled with microarrays to identify putative miRNAs implicated in beta cell regeneration. Altered expression of the selected miRNAs, including miR-132, was verified by RT-PCR. Potential targets of miR-132 were selected through bioinformatic data mining. Predicted miR-132 targets were validated for their changed RNA, protein expression levels, and signaling upon miR-132 knockdown and/or overexpression in mouse MIN6 and human EndoC-βH1 insulinoma cells. The ability of miR-132 to foster beta cell proliferation in vivo was further assessed in pancreatectomized miR-132−/− and control mice. Results Partial pancreatectomy significantly increased the number of BrdU+/insulin+ islet cells. Microarray profiling revealed that 14 miRNAs, including miR-132 and -141, were significantly upregulated in the LCM islets of the partially pancreatectomized mice compared to the LCM islets of the control mice. In the same comparison, miR-760 was the only downregulated miRNA. The changed expression of these miRNAs in the islets of the partially pancreatectomized mice was confirmed by RT-PCR only in the case of miR-132 and -141. Based on previous knowledge of its function, we focused our attention on miR-132. Downregulation of miR-132 reduced the proliferation of MIN6 cells while enhancing the levels of pro-apoptotic cleaved caspase-9. The opposite was observed in miR-132 overexpressing MIN6 cells. Microarray profiling, RT-PCR, and immunoblotting of the latter cells demonstrated their downregulated expression of Pten with concomitant increased levels of pro-proliferative factors phospho-Akt and phospho-Creb and inactivation of pro-apoptotic Foxo3a via its phosphorylation. Downregulation of Pten was further confirmed in the LCM islets of pancreatectomized mice compared to the sham-operated mice. Moreover, overexpression of miR-132 correlated with increased proliferation of EndoC-βH1 cells. The regeneration of beta cells following partial pancreatectomy was lower in the miR-132/212−/− mice than the control littermates. Conclusions This study provides compelling evidence about the critical role of miR-132 for the regeneration of mouse islet beta cells through the downregulation of its target Pten. Hence, the miR-132/Pten/Akt/Foxo3 signaling pathway may represent a suitable target to enhance beta cell mass., Highlights • miR-132 is induced in mouse islets upon partial pancreatectomy. • miR-132 promotes regeneration of β-cells in vivo following partial pancreatectomy. • miR-132 fosters in vitro proliferation/survival through Pten/Akt/Foxo3 signaling. • Downstream targets of miR-132 were identified in pancreatic β-cells. • miR-132−/− mice have impaired β-cell proliferation.
- Published
- 2020
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