OXIDANT INDUCED CELL SIGNALING IN WOUND HEALING

University Of California San Francisco, San Francisco CA

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Abstract

Wound healing is a complex process beginning with an inflammatory response leading to tissue formation and remodeling. Angiogenesis is the process by which new blood capillaries are formed at the wound site by migration, proliferation and organization of vascular endothelial cells. In wound healing, angiogenesis plays a central role. As yet the primary cellular signals initiating angiogenesis are not well known. In a variety of cell types, reactive oxygen and nitrogen species (ROS/RNS) are known to markedly increase expression and release of vascular endothelial growth factor (VEGF). It has been established that VEGF is a major long-term angiogenic stimulus at the wound site. As leukocytes that accumulate in the wound region produce ROS/RNS, it can be hypothesized that these oxidants play a role in the induction of angiogenesis. Thus, the major objective of this proposal is to investigate whether oxidants present in a wound environment regulate angiogenesis via the modulation of VEGF activity. The proposed study will focus on VEGF expression and release by different cells (e.g., keratinocyte, macrophages and fibroblasts) associated with wound. Studies will be carried out using both primary as well as transformed human cells. The research design is based on a four- step approach. In the first step, we will investigate the efficacy and mechanisms through which ROS/RNS induce VEGF in cells that are local to the wound site. Specifically, cultured keratinocytes and macrophages will be exposed to a series of oxidant to, and assay for VEGF expression and release. In the second step, we will determine the potential modulation of the oxidant induced-VEGF production by cytokines/metabolites and copper ions that might potentially accumulate or present concomitantly at the wound site. In the third step, we will investigate how intracellular antioxidants influence oxidant-induced VEGF production. In the fourth and final step, we will determine the signaling cascade that is recruited upon oxidant exposure leading to VEGF expression and release. The results from this study can be expected to yield better understanding of the molecular mechanisms regulating angiogenesis and therefore, should contribute towards the development of new principles in the control of wound healing.