Frataxin deficiency in pancreatic islets causes diabetes due to loss of beta cell mass

J Clin Invest. 2003 Aug;112(4):527-34. doi: 10.1172/JCI18107.

Abstract

Diabetes is caused by an absolute (type 1) or relative (type 2) deficiency of insulin-producing beta cells. We have disrupted expression of the mitochondrial protein frataxin selectively in pancreatic beta cells. Mice were born healthy but subsequently developed impaired glucose tolerance progressing to overt diabetes mellitus. These observations were explained by impairment of insulin secretion due to a loss of beta cell mass in knockout animals. This phenotype was preceded by elevated levels of reactive oxygen species in knockout islets, an increased frequency of apoptosis, and a decreased number of proliferating beta cells. Hence, disruption of the frataxin gene in pancreatic beta cells causes diabetes following cellular growth arrest and apoptosis, paralleled by an increase in reactive oxygen species in islets. These observations might provide insight into the deterioration of beta cell function observed in different subtypes of diabetes in humans.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Animals
  • Apoptosis
  • Cell Division
  • DNA, Complementary / metabolism
  • Diabetes Mellitus / metabolism*
  • Exons
  • Genotype
  • Glucose Tolerance Test
  • Insulin / metabolism
  • Insulin Secretion
  • Iron-Binding Proteins / genetics*
  • Iron-Binding Proteins / physiology*
  • Islets of Langerhans / metabolism*
  • Magnetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Microscopy, Fluorescence
  • Reactive Oxygen Species
  • Time Factors
  • Tissue Distribution

Substances

  • DNA, Complementary
  • Insulin
  • Iron-Binding Proteins
  • Reactive Oxygen Species
  • frataxin