MiR-132 controls pancreatic beta cell proliferation and survival through Pten/Akt/Foxo3 signaling

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Hassan Mziaut - , Molecular Diabetology, TUD Dresden University of Technology, German Center for Diabetes Research (DZD e.V.) (Author)
  • Georg Henniger - , TUD Dresden University of Technology (Author)
  • Katharina Ganss - , TUD Dresden University of Technology, German Center for Diabetes Research (DZD e.V.) (Author)
  • Sebastian Hempel - , Department of Visceral, Thoracic and Vascular Surgery, TUD Dresden University of Technology (Author)
  • Steffen Wolk - , Department of Visceral, Thoracic and Vascular Surgery, TUD Dresden University of Technology (Author)
  • Johanna McChord - , TUD Dresden University of Technology (Author)
  • Kamal Chowdhury - , Max Planck Institute for Biophysical Chemistry (Karl Friedrich Bonhoeffer Institute) (Author)
  • Philippe Ravassard - , Sorbonne Université (Author)
  • Klaus Peter Knoch - , Molecular Diabetology, TUD Dresden University of Technology, German Center for Diabetes Research (DZD e.V.) (Author)
  • Christian Krautz - , Friedrich-Alexander University Erlangen-Nürnberg (Author)
  • Jürgen Weitz - , Department of Visceral, Thoracic and Vascular Surgery, National Center for Tumor Diseases (Partners: UKD, MFD, HZDR, DKFZ), TUD Dresden University of Technology (Author)
  • Robert Grützmann - , Friedrich-Alexander University Erlangen-Nürnberg (Author)
  • Christian Pilarsky - , Friedrich-Alexander University Erlangen-Nürnberg (Author)
  • Michele Solimena - , Molecular Diabetology, TUD Dresden University of Technology, German Center for Diabetes Research (DZD e.V.), Max Planck Institute of Molecular Cell Biology and Genetics (Author)
  • Stephan Kersting - , Friedrich-Alexander University Erlangen-Nürnberg (Author)

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.

Details

Original languageEnglish
Pages (from-to)150-162
Number of pages13
JournalMolecular metabolism
Volume31
Publication statusPublished - Jan 2020
Peer-reviewedYes

External IDs

PubMed 31918917

Keywords

ASJC Scopus subject areas

Keywords

  • Apoptosis, miR-132, Pancreatectomy, Pten/Akt/Foxo3a, β cell regeneration