Glucose stimulates microRNA-199 expression in murine pancreatic β-cells

Joao Pedro Werneck-De-Castro, X. Manuel Blandino-Rosano, Denise Hilfiker-Kleiner, Ernesto Bernal-Mizrachi

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

MicroRNA 199 (miR-199) negatively impacts pancreatic β-cell function and its expression is highly increased in islets from diabetic mice as well as in plasma of diabetic patients. Here we investigatedhowmiR- 199 expression is regulated inβ-cells by assessing expression of miR-199 precursors (primiR-199a1, primiR-199a2, and primiR-199b) and mature miR-199 (miR-199-3p and miR- 199-5p) and promoter transcriptional activity assays in mouse islets and mouse insulinoma cells (MIN6) under different stimuli. We found that mouse islets equally express miR-199-3p and miR- 199-5p. However, the primiRNA expression levels differed; although primiR-199a1 expression was about 30% greater than that of primiR-199a2, primiR-199b is barely detected in islets. We observed a 2-fold increase in primiR-199a1 and primiR-199a2 mRNA levels in mouse islets cultured in 10mM glucose compared with 5.5mMglucose. Similar responses to glucose were observed in MIN6 cells. Exposure to 30mM KCl to induce membrane depolarization and calcium influx increased expression of primiR-199a2 but not of primiR-199a1 in MIN6 cells, indicating that calcium influx was involved. Transcriptional activity studies in MIN6 cells also revealed that primiR-199a2 promoter activity was enhanced by glucose and reduced by 2-deoxy-D-glucose-induced starvation. KCl and the potassium channel blocker tolbutamide also stimulated primiR-199a2 promoter activity. Calcium channel blockade by nifedipine reduced primiR-199a2 promoter activity in MIN6 cells, and diazoxide-mediated calcium influx inhibition blunted glucose up-regulation of miR-199-3p in islets. In conclusion, we uncover that glucose acutely up-regulates miR-199 family expression in β-cells. Glucose metabolism and calcium influx are involved in primiR-199a2 expression but not primiR-199a1 expression.

Original languageEnglish (US)
Pages (from-to)1261-1270
Number of pages10
JournalJournal of Biological Chemistry
Volume295
Issue number5
DOIs
StatePublished - 2020

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Glucose stimulates microRNA-199 expression in murine pancreatic β-cells'. Together they form a unique fingerprint.

Cite this