Contribution of oxidative stress and NADPH oxidase (NOXes) diabetes-associated vascular injury: study in knockout mice

Abstract

Diabetes Mellitus stands out as one of the most important non-transmissible chronic diseases worldwide. Epidemiological, clinical and experimental data indicate a causal association between hyperglycemia and diabetic complications. Exact mechanisms for this remain elusive but hyperglycaemia-induced oxidative stress appears to play an important role in the increased risk of diabetic complications, including diabetic nephropathy, cardiovascular disease and retinopathy. This proposal aims to determine the role of NOX1/NOX4-derived ROS in the pathogenesis of diabetic vasculopathy due to type 2 diabetes and, therefore, to elucidate redox-sensitive molecular mechanisms of the disease. Our hypothesis is that diabetes is associated with tissue-specific activation of different NOX isoforms: hyperactivation of vascular NOX1 causing vascular injury and upregulation of renal NOX4 leading to nephropathy. This NOX isoform effect is related to differential expression of p47phox and its isoform NOXO1. We will focus on two specific aims: 1) db/db mice (C57BLKS/JLepr), considered a diabetic nephropathy model, will be crossed with knockout mice NOX1 (NOX1-/-), NOX 4 (NOX4-/-) e p47phox-/-, and the vascular alterations will be characterized. To elucidate the role of NOXes1/4 and p47phox in diabetes-associated renal and vascular complications, db/db (C57BLKS/JLepr) mice will be crossed with NOX1-/-, NOX4-/- and p47phox-/- mice. This set of experiments will be performed at the University of Ottawa. 2) mesenteric artery will be isolated of diabetic and control mice. Vascular cultured cells (smooth muscle) from these animals will be used to determine the molecular pathways that are involved on ROS generation mediated by NOXes 1 and 4, as well as, the pathway NOX-dependent for proliferation and inflammation. (AU)