Diabetic microvascular complications have been considered to be mediated by a glucose-driven increase in mitochondrial superoxide anion production. Here, we report that superoxide production was reduced in the kidneys of a steptozotocin-induced mouse model of type 1 diabetes, as assessed by in vivo real-time transcutaneous fluorescence, confocal microscopy, and electron paramagnetic resonance analysis. Reduction of mitochondrial biogenesis and phosphorylation of pyruvate dehydrogenase (PDH) were observed in kidneys from diabetic mice. These observations were consistent with an overall reduction of mitochondrial glucose oxidation. Activity of AMPK, the major energy-sensing enzyme, was reduced in kidneys from both diabetic mice and humans. Mitochondrial biogenesis, PDH activity, and mitochondrial complex activity were rescued by treatment with the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR). AICAR treatment induced superoxide production and was linked with glomerular matrix and albuminuria reduction in the diabetic kidney. Furthermore, diabetic heterozygous superoxide dismutase 2 (
Laura L. Dugan, Young-Hyun You, Sameh S. Ali, Maggie Diamond-Stanic, Satoshi Miyamoto, Anne-Emilie DeCleves, Aleksander Andreyev, Tammy Quach, San Ly, Grigory Shekhtman, William Nguyen, Andre Chepetan, Thuy P. Le, Lin Wang, Ming Xu, Kacie P. Paik, Agnes Fogo, Benoit Viollet, Anne Murphy, Frank Brosius, Robert K. Naviaux, Kumar Sharma
EPR spectra and ROS release rate in control and diabetic kidney mitochondria.