The overall aim of this grant is to elucidate the novel linkage between copper transport protein """"""""Antioxidant1 (Atox1)"""""""" and """"""""NADPH oxidase"""""""" involved in inflammatory angiogenesis. Ischemic disease is a leading cause of morbidity and mortality in worldwide. Neovascularization is an important repair process in response to ischemia, which depends on angiogenesis, inflammation and reactive oxygen species (ROS). Copper (Cu), an essential micronutrient, is involved in physiological repair processes such as wound healing and angiogenesis as well as in various pathophysiologies including tumor growth, atherosclerosis and inflammatory diseases. Since excess Cu is toxic, bioavailability of intracellular Cu is tightly controlled by Cu transport proteins such as Cu chaperone Atox1. Our laboratories provided the first evidence that Atox1 functions as a Cu-dependent transcription factor to regulate Cu-induced cell growth. Furthermore, we are one of the first to demonstrate that ROS derived from NADPH oxidase (Nox) play an important role in angiogenic signaling in endothelial cells (ECs) as well as postnatal angiogenesis in response to ischemic injury. However, the role of Cu transport proteins in inflammatory angiogenesis and its linkage with Nox are entirely unknown. Our preliminary data suggest that Atox1 deficient mice have impaired angiogenesis and inflammatory cell recruitment due to decrease in endothelial ROS production in ischemic tissues. Bone marrow (BM) reconstitution indicates that Atox1 in ECs, but not BM cells, is required for post-ischemic revascularization. Based on new preliminary data, we hypothesize that Atox1 functions as a novel regulator for Nox by transcriptional regulation of p47phox as well as activating Rac1;both are critical cytosolic components of Nox, in a Cu-dependent manner. This in turn promotes ROS-dependent signaling linked to inflammatory and angiogenic responses in ECs, which contributes to neovascularization in response to ischemic injury.
Aim1 will focus on establishing a role of Atox1 in regulating NADPH oxidase and ROS-dependent inflammatory and angiogenic signaling and function in ECs in a Cu-dependent manner.
Aim 2 will focus on identifying molecular mechanisms of how Atox1 is involved in activation of NADPH oxidase through transcriptional regulation of p47phox and activating Rac1 via binding to a Rac1-binding scaffold protein IQGAP1 in ECs in a Cu-dependent manner.
Aim 3 will focus on determining the functional role of Atox1 in neovascularization in vivo by regulating ROS production, angiogenesis and inflammatory cell recruitment in injured tissues in a Cu-dependent manner using hindlimb ischemia model with Atox1-/- mice. Bone marrow transplantation, in vivo intravital microscopy and bioluminescence imaging, highly innovative Cu imaging analysis in vitro and in vivo will be performed. Our study will provide novel insight into Cu transport protein and their regulators as potential therapeutic targets for treatment of angiogenesis- and inflammation-dependent ischemic cardiovascular diseases.
Ischemic disease, the most common cause of morbidity and death in western countries, is increasing worldwide and is due in part to impaired formation of new blood vessels, which depends on angiogenesis, inflammation, and reactive oxygen species. Copper is an essential nutrient and is shown to be involved in regulating inflammation and angiogenesis with unknown mechanism. This proposal will provide novel insights into Cu transport proteins and its regulators as potential therapeutic targets for inflammation- and angiogenesis-dependent ischemic cardiovascular diseases.
|Sudhahar, Varadarajan; Okur, Mustafa Nazir; Bagi, Zsolt et al. (2018) Akt2 (Protein Kinase B Beta) Stabilizes ATP7A, a Copper Transporter for Extracellular Superoxide Dismutase, in Vascular Smooth Muscle: Novel Mechanism to Limit Endothelial Dysfunction in Type 2 Diabetes Mellitus. Arterioscler Thromb Vasc Biol 38:529-541|
|Fang, Milie M; Barman, Pijus K; Thiruppathi, Muthusamy et al. (2018) Oxidant Signaling Mediated by Nox2 in Neutrophils Promotes Regenerative Myelopoiesis and Tissue Recovery following Ischemic Damage. J Immunol 201:2414-2426|
|Robinson, Austin T; Fancher, Ibra S; Sudhahar, Varadarajan et al. (2017) Short-term regular aerobic exercise reduces oxidative stress produced by acute in the adipose microvasculature. Am J Physiol Heart Circ Physiol 312:H896-H906|
|Kim, Young-Mee; Kim, Seok-Jo; Tatsunami, Ryosuke et al. (2017) ROS-induced ROS release orchestrated by Nox4, Nox2, and mitochondria in VEGF signaling and angiogenesis. Am J Physiol Cell Physiol 312:C749-C764|
|Delaney, M Keegan; Kim, Kyungho; Estevez, Brian et al. (2016) Differential Roles of the NADPH-Oxidase 1 and 2 in Platelet Activation and Thrombosis. Arterioscler Thromb Vasc Biol 36:846-54|
|Park, Changwon; Lee, Tae-Jin; Bhang, Suk Ho et al. (2016) Injury-Mediated Vascular Regeneration Requires Endothelial ER71/ETV2. Arterioscler Thromb Vasc Biol 36:86-96|
|Das, Archita; Sudhahar, Varadarajan; Chen, Gin-Fu et al. (2016) Endothelial Antioxidant-1: a Key Mediator of Copper-dependent Wound Healing in vivo. Sci Rep 6:33783|
|Negi, Smita I; Jeong, Euy-Myoung; Shukrullah, Irfan et al. (2015) Renin-Angiotensin Activation and Oxidative Stress in Early Heart Failure with Preserved Ejection Fraction. Biomed Res Int 2015:825027|
|Chen, Gin-Fu; Sudhahar, Varadarajan; Youn, Seock-Won et al. (2015) Copper Transport Protein Antioxidant-1 Promotes Inflammatory Neovascularization via Chaperone and Transcription Factor Function. Sci Rep 5:14780|
|Chatterjee, Shampa; Fujiwara, Keigi; Pérez, Néstor Gustavo et al. (2015) Mechanosignaling in the vasculature: emerging concepts in sensing, transduction and physiological responses. Am J Physiol Heart Circ Physiol 308:H1451-62|
Showing the most recent 10 out of 16 publications