The capacity for tissue repair is a fundamental property of multicellular organisms that is often critical for survival. Despite its biological and clinical importance, the signals that initiate and terminate epidermal wound closure remain obscure, as do the genes required to execute this process. This is partly due to the complexity of wound repair responses in vertebrate model organisms and the fact that tissue repair has not been studied extensively in simpler model genetic organisms where rapid gene discovery and precise analysis of gene function are greatly facilitated. This research project focuses on the molecular genetic control of postembryonic wound healing. Our guiding hypothesis is that there is a conserved molecular genetic program of cell-cell signaling events that initiates, regulates, executes, and terminates the repair process. To test this hypothesis in a genetically tractable model system we have established epidermal wound healing assays using Drosophila larvae and demonstrated that wound closure requires the Drosophila Jun N-terminal kinase (JNK) and eight other genes we identified in a pilot conditional genetic screen for wound closure mutants. For this pilot screen we developed transgenic reporter larvae that allow live visualization of wound closure as well as epidermal-specific expression of exogenous RNAi transgenes that could interfere with or enhance this process. Our long term objective is to use our unique assays and tools to identify the complement of genes required for efficient wound closure and determine the function of these genes during wound closure. Our shorter term goals are enumerated in the following specific aims: 1. to test the hypothesis that wound- induced JNK signaling is activated by the Drosophila homolog of the PDGF/VEGF receptor, PVR, a receptor tyrosine kinase identified in our pilot screen. 2. To test the hypothesis that JNK signaling pathway activation initiates cell migration in wound-responsive cells. 3. To identify and characterize novel genes required for wound closure by expanding our conditional genetic screening strategy. This project represents the first systematic study of postembryonic wound closure in a model genetic organism and has great potential for uncovering the elusive signals that control wound closure. Given the conservation of genes required for most fundamental processes we expect that this project will inform our understanding of wound closure in vertebrates and in pathophysiological states, such as cancer, where the wound healing response is thought to be improperly activated or regulated. This research project employs a model genetic organism, the fruit fly, to uncover the genetic control of postembryonic wound healing, a process of immediate relevance to human health. Wound healing is critical for recovery from trauma and surgery, both of which are common occurrences. Given the conservation of genes required for most fundamental biological processes we expect that this project will inform our understanding of wound closure in vertebrates and in pathophysiological states, such as cancer and a variety of skin diseases, where the wound healing response is thought to be improperly activated or regulated.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM083031-05
Application #
8228091
Study Section
Development - 2 Study Section (DEV2)
Program Officer
Somers, Scott D
Project Start
2008-05-15
Project End
2013-02-28
Budget Start
2012-03-01
Budget End
2013-02-28
Support Year
5
Fiscal Year
2012
Total Cost
$286,777
Indirect Cost
$100,558
Name
University of Texas MD Anderson Cancer Center
Department
Biochemistry
Type
Other Domestic Higher Education
DUNS #
800772139
City
Houston
State
TX
Country
United States
Zip Code
77030
Anderson, Aimee E; Galko, Michael J (2014) Rapid clearance of epigenetic protein reporters from wound edge cells in Drosophila larvae does not depend on the JNK or PDGFR/VEGFR signaling pathways. Regeneration (Oxf) 1:11-25
Scherfer, Christoph; Han, Violet C; Wang, Yan et al. (2013) Autophagy drives epidermal deterioration in a Drosophila model of tissue aging. Aging (Albany NY) 5:276-87
Lesch, Christine; Jo, Juyeon; Wu, Yujane et al. (2010) A targeted UAS-RNAi screen in Drosophila larvae identifies wound closure genes regulating distinct cellular processes. Genetics 186:943-57
Wu, Yujane; Brock, Amanda R; Wang, Yan et al. (2009) A blood-borne PDGF/VEGF-like ligand initiates wound-induced epidermal cell migration in Drosophila larvae. Curr Biol 19:1473-7