BME PhD Proposal Presentation: Daniel Roy

Development of Novel Fibronectin Matrix Mimetics to Promote Healing of Chronic, Cutaneous Wounds

Supervised by Prof. Denise Hocking

Abstract

Cutaneous wound healing is a cell-dependent process in which complete wound closure is achieved in as little as two weeks. Chronic, non-healing wounds affect more than 6.5 million people in the United States annually. Chronic wounds cause pain and discomfort to the patient and may require drastic medical intervention such as amputation. Developing treatments that promote healing of chronic wounds is a challenge that has been met with little success by the medical community. Fibronectin (FN) is a large adhesive glycoprotein that is rapidly up-regulated in response to tissue injury. Decreased FN levels are associated with non-healing wounds. The insoluble, extracellular matrix (ECM) form of FN stimulates cell activities critical to timely wound healing including cell growth, migration, and contractility. The biological activity of EM FN is due, in part, to an exposed heparin-binding site in the III1 module of EM FN. I hypothesize that providing a non-healing wound with an EM FN mimetic will accelerate wound closure by stimulating the cell activities essential for efficient wound repair.

Our lab has engineered a recombinant, EM FN mimetic (GST/III-1H,8-10) that couples the heparin-binding fragment of FNIII1 (FNIII-1H) to the integrin-binding domain of FN (FNIII8-10). GST/III-1H,8-10 supports cell adhesion, migration, and contractility and increases the rate of cell proliferation to a greater extent than full-length FN. To produce smaller, equally bioactive EM FN mimetics, a series of deletion mutants of GST/III-1H,8-10 were constructed. Protein constructs containing the integrin-binding Arg-Gly-Asp (RGD) sequence, FNIII-1H and FNIII8 stimulated cell growth to a similar extent as GST/III-1H,8-10. In Aim 1 of this proposal, I will develop an FN matrix mimetic that stimulates dermal fibroblast growth and myofibroblast contractility. In Aim 2, the effects of FN matrix mimetics on fibroblast and keratinocyte migration will be determined. From these studies, a therapeutic protein regimen will be developed in Aim 3 in which the FN matrix mimetics that best stimulate cell growth, migration and contractility will be topically added to full-thickness skin wounds in diabetic mice in an effort to accelerate the closure of chronic wounds.