Copper transporter ATP7A protects against endothelial dysfunction in type 1 diabetic mice by regulating extracellular superoxide dismutase

Varadarajan Sudhahar, Norifumi Urao, Jin Oshikawa, Ronald D. McKinney, Roxana M. Llanos, Julian F.B. Mercer, Masuko Ushio-Fukai, Tohru Fukai

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Vasculopathy is a major complication of diabetes; however, molecular mechanisms mediating the development of vasculopathy and potential strategies for prevention have not been identified. We have previously reported that C-peptide prevents diabetic vasculopathy by inhibiting reactive oxygen species (ROS)-mediated endothelial apoptosis. To gain further insight into ROS-dependent mechanism of diabetic vasculopathy and its prevention, we studied high glucose-induced cytosolic and mitochondrial ROS production and its effect on altered mitochondrial dynamics and apoptosis. For the therapeutic strategy, we investigated the vasoprotective mechanism of C-peptide against hyperglycemia-induced endothelial damage through the AMP-activated protein kinase a (AMPKα) pathway using human umbilical vein endothelial cells and aorta of diabetic mice. High glucose (33 mmol/L) increased intracellular ROS through a mechanism involving interregulation between cytosolic and mitochondrial ROS generation. C-peptide (1 nmol/L) activation of AMPKα inhibited high glucose-induced ROS generation, mitochondrial fission, mitochondrial membrane potential collapse, and endothelial cell apoptosis. Additionally, the AMPK activator 5-aminoimidazole-4-carboxamide 1-b-D-ribofuranoside and the antihyperglycemic drug metformin mimicked protective effects of C-peptide. C-peptide replacement therapy normalized hyperglycemiainduced AMPKα dephosphorylation, ROS generation, and mitochondrial disorganization in aorta of diabetic mice. These findings highlight a novel mechanism by which C-peptide activates AMPKα and protects against hyperglycemia-induced vasculopathy.

Original languageEnglish (US)
Pages (from-to)3839-3850
Number of pages12
JournalDiabetes
Volume62
Issue number11
DOIs
StatePublished - Nov 1 2013
Externally publishedYes

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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