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ludc web

Anna Wendt

Assistant researcher

ludc web

Osteopontin affects insulin vesicle localization and Ca2+ homeostasis in pancreatic beta cells from female mice

Author

  • Anna Wendt
  • Ines Mollet
  • Anki Knutsson
  • Victor S. Bolmgren
  • Anna Hultgårdh
  • Maria F. Gomez
  • Lena Eliasson

Summary, in English

Type 2 diabetic patients suffer from insulin resistance and reduced insulin secretion. Osteopontin (OPN), a versatile protein expressed in several tissues throughout the body including the islets of Langerhans, has previously been implicated in the development of insulin resistance. Here we have investigated the role of OPN in insulin secretion using an OPN knock out mouse model (OPN-/-). Ultra-structural analyzes of islets from OPN-/- and WT mice indicated weaker cell-cell connections between the islet cells in the OPN-/- mouse compared to WT. Analysis of the insulin granule distribution in the beta cells showed that although OPN-/- and WT beta cells have the same number of insulin granules OPN-/- beta cells have significantly fewer docked granules. Both OPN-/- and WT islets displayed synchronized Ca2+ oscillations indicative of an intact beta cell communication. OPN-/- islets displayed higher intracellular Ca2+ concentrations when stimulated with 16.7 mM glucose than WT islets and the initial dip upon elevated glucose concentrations (which is associated with Ca2+ uptake into ER) was significantly lower in these islets. Glucose-induced insulin secretion was similar in OPN-/- and WT islets. Likewise, non-fasted blood glucose levels were the same in both groups. In summary, deletion of OPN results in several minor beta-cell defects that can be compensated for in a healthy system.

Department/s

  • Diabetes - Islet Cell Exocytosis
  • Vessel Wall Biology
  • Diabetic Complications
  • EXODIAB: Excellence of Diabetes Research in Sweden

Publishing year

2017-01-01

Language

English

Publication/Series

PLoS ONE

Volume

12

Issue

1

Document type

Journal article

Publisher

Public Library of Science

Topic

  • Endocrinology and Diabetes

Keywords

  • Type 2 diabetesmellitus
  • Osteopontin
  • mice
  • Ca homeostasis

Status

Published

Research group

  • Diabetes - Islet Cell Exocytosis
  • Vessel Wall Biology
  • Diabetic Complications

ISBN/ISSN/Other

  • ISSN: 1932-6203