Angiogenic Regulators in Ischemic Disorders

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 DESCRIPTION (provided by applicant): Physiological as well as pathological angiogenesis denotes one of the hottest areas of biomedical research today. Therapeutic angiogenesis (increase in vessel density and blood flow) can repair myocardial infarction, limb ischemia and arteriosclerosis whereas inhibition of pathological angiogenesis (inhibition of vessel formation and blood flow) can treat retinopathies and malignant tumor growth. Inspite significant progress in medical, interventional and surgical therapy in the clinics for heart failure and critical limb ischemia models, still the proper answer to addressing these illnesses and their treatment still remains elusive. Therapeutic angiogenesis, which is probably the only treatment available so far for ischemic diseases, has had limited success. Our proposed aims will help elucidate the underlying molecular mechanism of antigenic pathway, reveal new antigenic modulators by using ischemically challenged, pre-clinical models. We will use state-of- the-art genetic techniques to generate novel transgenic animals and use them to perform a rescue-impaired angiogenesis technique in ischemic organs/tissues. Here we are going to examine a previously unknown function of VEGF in an E3 ligase Pellino-1 (Peli1) mediated regulation of Thioredoxin-1 (Trx1) in the activation of angiogenesis. We found that Peli1 serve as a critical positive regulator of neovascularization in Hind limb and myocardial ischemia by regulating and inhibiting thioredoxin interacting protein (TXNIP). Our long-term goal of this project is to understand and explore the cause of impairment of angiogenesis in peripheral arterial disease (PAD) using hind limb ischemia model (HLI) and myocardial infarction (MI). Therefore, our overall hypothesis is that ischemia leads to abnormal or impaired angiogenesis and deteriorated blood perfusion due to the disruption of Peli1-Trx1-VEGF signaling and loss of redox equilibrium in the ischemic tissue. We proposed three specific aims: Specific Aim I- To examine Peli1 mediated neovascularization in ischemically challenged models (HLI, MI). Specific Aim II - To elucidate a downstream molecular mechanism of Peli1- mediated redox signaling in various diseased models. Specific Aim III- To examine and assess the clinical and functional significance of Peli1 using genetic models. Genetically engineered Peli1 and Flk-1 mice will be used to evaluate our hypothesis in relation to angiogenesis in models of ischemic injury as proposed. This study will adapt multidisciplinary approaches using various modern techniques and powerful animal models. Collectively, the proposed study will contribute to our understanding of the molecular mechanism of Peli1 mediated activation of Trx1, which controls the redox state from shifting to an overly reductive or an oxidative environment that generally disrupts various modulators (HO-1, VEGF) related to angiogenic signaling. We believe that Peli1 is a potential candidate for small molecule treatment to manage ischemic disorders associated with angiogenesis.