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ludc web

Anna Wendt

Assistant researcher

ludc web

Bone morphogenetic protein 4 inhibits insulin secretion from rodent beta cells through regulation of calbindin1 expression and reduced voltage-dependent calcium currents

Author

  • Gitte L. Christensen
  • Maria L. B. Jacobsen
  • Anna Wendt
  • Ines Mollet
  • Josefine Friberg
  • Klaus S. Frederiksen
  • Michael Meyer
  • Christine Bruun
  • Lena Eliasson
  • Nils Billestrup

Summary, in English

Aims/hypothesis Type 2 diabetes is characterised by progressive loss of pancreatic beta cell mass and function. Therefore, it is of therapeutic interest to identify factors with the potential to improve beta cell proliferation and insulin secretion. Bone morphogenetic protein 4 (BMP4) expression is increased in diabetic animals and BMP4 reduces glucose-stimulated insulin secretion (GSIS). Here, we investigate the molecular mechanism behind this inhibition. Methods BMP4-mediated inhibition of GSIS was investigated in detail using single cell electrophysiological measurements and live cell Ca2+ imaging. BMP4-mediated gene expression changes were investigated by microarray profiling, quantitative PCR and western blotting. Results Prolonged exposure to BMP4 reduced GSIS from rodent pancreatic islets. This inhibition was associated with decreased exocytosis due to a reduced Ca2+ current through voltage-dependent Ca2+ channels. To identify proteins involved in the inhibition of GSIS, we investigated global gene expression changes induced by BMP4 in neonatal rat pancreatic islets. Expression of the Ca2+-binding protein calbindin1 was significantly induced by BMP4. Overexpression of calbindin1 in primary islet cells reduced GSIS, and the effect of BMP4 on GSIS was lost in islets from calbindin1 (Calb1) knockout mice. Conclusions/interpretation We found BMP4 treatment to markedly inhibit GSIS from rodent pancreatic islets in a calbindin1-dependent manner. Calbindin1 is suggested to mediate the effect of BMP4 by buffering Ca2+ and decreasing Ca2+ channel activity, resulting in diminished insulin exocytosis. Both BMP4 and calbindin1 are potential pharmacological targets for the treatment of beta cell dysfunction.

Department/s

  • Diabetes - Islet Cell Exocytosis
  • EXODIAB: Excellence of Diabetes Research in Sweden

Publishing year

2015

Language

English

Pages

1282-1290

Publication/Series

Diabetologia

Volume

58

Issue

6

Document type

Journal article

Publisher

Springer

Topic

  • Endocrinology and Diabetes

Keywords

  • Beta cells
  • BMP4
  • Calb1
  • Calbindin1
  • Diabetes
  • Exocytosis
  • Insulin
  • secretion

Status

Published

Research group

  • Diabetes - Islet Cell Exocytosis

ISBN/ISSN/Other

  • ISSN: 1432-0428