We recently reported the identification of a novel family of proteins, termed the LaNts, which are related to the laminin and netrin families of extracellular matrix proteins. Moreover, through a knockdown approach, we identified a role for the LaNts in keratinocyte adhesion and migration, therefore strongly implicating them as important mediators of epidermal integrity and wound healing. In the current proposal we plan to dramatically extend our previous findings to elucidate the precise mechanisms through which LaNts induce their functions. The project has three major components;firstly, due to their similarities with the netrin family of extracellular guidance cues, we will determine the cell surface receptor binding and signaling capabilities of the LaNts, the pathways modulated by them and the response of keratinocytes to LaNt mediated signaling. Secondly, based upon the presence of domains shared with the laminins, which regulate laminin network formation, we will assess biochemically, in 2D and in 3D cell cultures the role of the LaNts in extracellular matrix organization and its impact upon cell adhesion and wound healing. Finally, we will take our experiments into a complex tissue environment and study the impact of ablation of the LaNt proteins in a mouse model. This work will include an in depth analysis of healing of cutaneous wounds in the mutant animals and determination of exogenous addition of LaNt protein is capable of enhancing wound healing in mutant or normal animals. Together this project will dramatically expand, not only our understanding of a new family of proteins but also will have broader and potentially therapeutic implications for the understanding of extracellular matrix function and epidermal wound healing. This proposal takes advantage of the collaborative environment at Northwestern University and includes training in various light and electron microscopy techniques, in 3D cultures and in mouse wound healing. In addition the training environment will provide numerous opportunities for career development through national research presentations, collaborations, mentoring students, and training in the responsible conduct of research.

Public Health Relevance

- Lay summary The outer layer of the skin (the epidermis) is separated from an inner layer (the dermis) by a specialized extracellular matrix structure termed the basement membrane. In unwounded skin the basement membrane provides an attachment point for the cells of the epidermis while, in response to wounding, basement membrane proteins provide the surface over which epidermal cells move to close a wound. We recently identified a new family of protein components of the basement membrane and, based on our recent data, we hypothesize that members of this family regulate basement membrane formation during development and wound healing. In this proposal our goal is to investigate the precise function of these new proteins with the view of opening a new avenue of research toward future wound healing therapies.

National Institute of Health (NIH)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Career Transition Award (K99)
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Arthritis and Musculoskeletal and Skin Diseases Special Grants Review Committee (AMS)
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Tseng, Hung H
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Northwestern University at Chicago
Anatomy/Cell Biology
Schools of Medicine
United States
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Hamill, Kevin J; Hiroyasu, Sho; Colburn, Zachary T et al. (2015) Alpha actinin-1 regulates cell-matrix adhesion organization in keratinocytes: consequences for skin cell motility. J Invest Dermatol 135:1043-1052
Hamill, Kevin J; Hopkinson, Susan B; Skalli, Omar et al. (2013) Actinin-4 in keratinocytes regulates motility via an effect on lamellipodia stability and matrix adhesions. FASEB J 27:546-56
Jeffe, Jill S; Seshadri, Sudarshan; Hamill, Kevin J et al. (2013) A role for anti-BP180 autoantibodies in chronic rhinosinusitis. Laryngoscope 123:2104-11
Hamill, Kevin J; Hopkinson, Susan B; Hoover, Paul et al. (2012) Fibronectin expression determines skin cell motile behavior. J Invest Dermatol 132:448-57