This career development program is an essential element in my plan to overcome previous career interruptions and become a productive independent investigator in the area of oxidative stress-induced disorders of insulin signaling. I will capitalize on my existing strengths (cellular signaling, oxidative stress), the scientific excellence of my mentors, Drs. Ralph DeFronzo and Robert Clark, in the fields of diabetes and inflammation, respectively, and the superb institutional environment in these research areas. Together with my mentors, I have designed a career plan that includes: 1) an advisory committee of accomplished researchers to provide both scientific input and career guidance;2) strategically selected conferences, seminars, and didactic courses;3) training in specific research technologies;and 4) a schedule of targets for grant and manuscript submissions. Peripheral insulin resistance and high blood glucose levels due to impaired glucose uptake and utilization in skeletal muscle are hallmarks of metabolic syndrome/type 2 diabetes. Inflammation and oxidative stress, through the production of reactive oxygen species (ROS), are consistently associated with the disease, however the primary source of these ROS and the mechanisms by which oxidative stress contributes to insulin resistance remain poorly understood. NADPH oxidases (NOX) are important sources of ROS and are identified as pathogenic factors in a number of disease states, including diabetes. While the role of NOX2 expressed in neutrophils is well described in host defense and inflammation, little is known about the potential roles of NOX2 expressed in skeletal muscle. Our central hypothesis is that NOX2-mediated ROS production by inflammatory neutrophils and/or skeletal muscle cells is a key factor in the development of insulin resistance. Our preliminary data show that oxidative stress and insulin resistance induced by a high fat diet is mitigated in NOX2 knockout mice. My research plan uses in vitro (primary myotube cultures) and in vivo (high fat diet fed mouse) models of insulin resistance and capitalizes on loss-of-function strategies (NOX2-null mice and primary cells) to implicate specifically NOX2. The experiments are designed to define the mechanisms by which NOX2-generated ROS induce inflammation and insulin resistance in skeletal muscle tissue.
The metabolic syndrome and type 2 diabetes are highly prevalent disorders that account for enormous morbidity and mortality in the United States and worldwide. The proposed work will fill in gaps in our understanding of the mechanisms involved in the pathogenesis of insulin resistance, a central feature of metabolic syndrome and type 2 diabetes, focusing on the roles of inflammation and oxidative stress. The new knowledge will lead to the identification and development of novel therapeutic targets that will aid for the prevention and treatment of metabolic syndrome/type 2 diabetes and its complications.
|Souto Padron de Figueiredo, Alvaro; Salmon, Adam B; Bruno, Francesca et al. (2015) Nox2 mediates skeletal muscle insulin resistance induced by a high fat diet. J Biol Chem 290:13427-39|
|Musset, Boris; Clark, Robert A; DeCoursey, Thomas E et al. (2012) NOX5 in human spermatozoa: expression, function, and regulation. J Biol Chem 287:9376-88|
|Halade, Ganesh V; El Jamali, Amina; Williams, Paul J et al. (2011) Obesity-mediated inflammatory microenvironment stimulates osteoclastogenesis and bone loss in mice. Exp Gerontol 46:43-52|