Oxidative stress induces loss of pericyte coverage and vascular instability in PGC-1α-deficient mice

Peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) is a regulator of mitochondrial oxidative metabolism and reactive oxygen species (ROS) homeostasis that is known to be inactivated in diabetic subjects. This study aimed to investigate the contribution of PGC-1α inactivation to the development of oxygen-induced retinopathy. We analyzed retinal vascular development in PGC-1α mice. Retinal vasculature of PGC-1α mice showed reduced pericyte coverage, a de-structured vascular plexus, and low perfusion. Exposure of PGC-1α mice to hyperoxia during retinal vascular development exacerbated these vascular abnormalities, with extensive retinal hemorrhaging and highly unstructured areas as compared with wild-type mice. Structural analysis demonstrated a reduction in membrane-bound VE-cadherin, which was suggestive of defective intercellular junctions. Interestingly, PGC-1α retinas showed a constitutive activation of the VEGF-A signaling pathway. This phenotype could be partially reversed by antioxidant administration, indicating that elevated production of ROS in the absence of PGC-1α could be a relevant factor in the alteration of the VEGF-A signaling pathway. Collectively, our findings suggest that PGC-1α control of ROS homeostasis plays an important role in the regulation of de novo angiogenesis and is required for vascular stability.This work was supported by grants from the Spanish ‘‘Ministerio de Economía y Competitividad’’ (Grant number SAF2009-07599 & SAF2012-37693 to M.M and CSD 2007-00020 to M.M.) and the ‘‘Comunidad de Madrid’’ (Grant Number S2010/BMD-2361 to M.M.).Peer Reviewe