Endothelial cell (EC) dysfunction is a common pathogenic framework of many of the diabetes-related micro- and macro- vascular complications. Reduced bioavailability of EC-released nitric oxide (NO) is a primary marker generally used for EC dysfunction. However, the molecular mechanisms of hyperglycemia induced reduced NO bioavailability remain poorly understood. [We hypothesize that the diabetic endothelial cell dysfunction/reduced NO bioavailability is mediated by reactive oxygen species (ROS) and is a results of increased interaction of NO and superoxide (O2-) at the endothelial cell level. The increased interactions results in higher peroxynitrite (ONOO-) formation, shifting nitric oxide synthase (eNOS) activity from NO production to O2? production, and EC damage. The deleterious effects can be prevented by reducing ROS formation and concentration.
Specific aims are designed to test these hypotheses.
Aim1. Determine the EC release of NO and O2- and cell damage in hyperglycemic conditions. Hypotheses are: i) the high glucose causes endothelial dysfunction over long periods by increasing ONOO- and O2- formation and ii) reduction in O2- formation is key to reducing endothelial dysfunction. We will perform the following experiments: i) determining the effect of high glucose on eNOS and NA(D)PH expressions, NO and superoxide releases, endothelial cell lipid peroxidation (an indicator of peroxynitrite formation) and apoptosis in human umbilical vein endothelial cells (HUVECs) over short and long time-periods, and ii) determining whether increasing NO or decreasing O2- formation will be effective in preventing effects of high glucose.
Aim2. Develop a reaction kinetic-transport computational model to simulate experiments of Aim1 and predict levels of NO, O2- and ONOO- at EC level. Hypotheses are: i) the NO concentration is reduced and ONOO- is increased due to high interaction between NO and O2- even though the NO release from endothelial cell increases in high glucose over short periods and ii) the NO concentration increases and ONOO- concentration decreases when O2- formation or concentration is reduced in high glucose.
Aim3. Develop a multi-scale computational model for NO, ROS (O2-), and reactive nitrogen species (RNS;ONOO-) transport in the microcirculation underlying the process of oxidative stress. Hypotheses are: i) endothelial cell dysfunction is a results of higher superoxide formation, ii) a reduction in ROS formation enhances NO bioavailability and iii) increased superoxide dismutase levels not only reduces the O2- levels but also increases the NO levels, and reduces NO formation through feedback mechanism. At EC level, we will model the regulation of eNOS and the release of NO and O2-. At tissue level, we will model a volume of tissue containing an arteriolar blood vessel and simulate transport of NO, ROS and RNS.] This combined experimental &computational approach is critical in our understanding of molecular mechanism of EC dysfunction and examine the potential therapies to treat EC dysfunction related vascular complications. Project Narrative Endothelial cell (EC) dysfunction is a common pathogenic framework of many of the diabetes-related micro- and macro- vascular complications. The molecular mechanisms of hyperglycemia induced endothelial cell dysfunction remain poorly understood. The proposed research will use integrated computational and experimental approaches to assess endothelial cell dysfunction caused by oxidative stress due to high glucose at the molecular, cellular and tissue levels. The integrated experimental measurements and computational modeling of oxidative stress will provide an optimum set of parameters that will not only improve endothelial cell dysfunction/NO bioavailability but also will guide us in the development of therapies for diabetes related vascular complications.
|Deonikar, Prabhakar; Abu-Soud, Husam M; Kavdia, Mahendra (2014) Computational analysis of nitric oxide biotransport to red blood cell in the presence of free hemoglobin and NO donor. Microvasc Res 95:15-25|
|Deonikar, Prabhakar; Kavdia, Mahendra (2013) Contribution of membrane permeability and unstirred layer diffusion to nitric oxide-red blood cell interaction. J Theor Biol 317:321-30|
|Patel, Hemang; Chen, Juan; Das, Kumuda C et al. (2013) Hyperglycemia induces differential change in oxidative stress at gene expression and functional levels in HUVEC and HMVEC. Cardiovasc Diabetol 12:142|
|Presnell, Caitlin E; Bhatti, Gaurav; Numan, Lidya S et al. (2013) Computational insights into the role of glutathione in oxidative stress. Curr Neurovasc Res 10:185-94|
|Chen, Juan; Rogers, Steven C; Kavdia, Mahendra (2013) Analysis of kinetics of dihydroethidium fluorescence with superoxide using xanthine oxidase and hypoxanthine assay. Ann Biomed Eng 41:327-37|
|Kar, Saptarshi; Kavdia, Mahendra (2013) Endothelial NO and Oýýýýýýýý production rates differentially regulate oxidative, nitroxidative, and nitrosative stress in the microcirculation. Free Radic Biol Med 63:161-74|
|Deonikar, Prabhakar; Kavdia, Mahendra (2012) Low micromolar intravascular cell-free hemoglobin concentration affects vascular NO bioavailability in sickle cell disease: a computational analysis. J Appl Physiol 112:1383-92|
|Kar, Saptarshi; Kavdia, Mahendra (2011) Modeling of biopterin-dependent pathways of eNOS for nitric oxide and superoxide production. Free Radic Biol Med 51:1411-27|
|Deonikar, Prabhakar; Kavdia, Mahendra (2010) A computational model for nitric oxide, nitrite and nitrate biotransport in the microcirculation: effect of reduced nitric oxide consumption by red blood cells and blood velocity. Microvasc Res 80:464-76|
|Deonikar, Prabhakar; Kavdia, Mahendra (2010) An integrated computational and experimental model of nitric oxide-red blood cell interactions. Ann Biomed Eng 38:357-70|
Showing the most recent 10 out of 12 publications