Cell motility is critical for the three major events in the healing of human skin wounds: re-epithelialization, angiogenesis and fibroplasia. What regulates the migration of various types of skin cells into the wound bed remains unknown. In un-wounded skin, skin cells are nourished by a plasma filtrate. When skin is wounded, skin cells at the wound edge experience an acute transition from plasma to serum. As the wound heals, there is a transition back to plasma in the newly healed environment. We found that a physiological function of this """"""""plasma >serum>plasma transition"""""""" is to orchestrate the orderly migration of human epidermal keratinocytes and human dermal fibroblasts (HDFs) (Henry et al. LANCET, 361:574-576, 2003; Bandyopadhay et al. J. Cell Biol. in press, 2006). Under these physiological conditions, we identified PDGF- BB as the major factor in human serum for HDF migration, the critical event in skin wound fibroplasias. This finding was a major advance for us because we have then been concentrating on the PDGF-BB's pro- motility signaling program for HDFs as a surrogate for human serum, which is unmanageably complex. To investigate the signaling events in primary HDFs, in which drug selection for stable cell lines is not an option, we established two lentiviral vector-derived systems that guarantee delivery of single or multiple genes (up-regulation) or siRNAs (down-regulation) into HDFs with unprecedented >90% gene transduction efficiency. With these systematic advances,we went on to identify seven signaling pathways, including FAK, Akt, Pak, PKC-delta, ERK1/2, p38 and JNK, essential for PDGF-BB-stimulated HDF migration (Li et al. Mol. Biol. Cell 15:294-305, 2004a;Fan et al. J. Invest. Derm., 2006, in press). The primary reason fordoing this way was because we found that few of these pathways alone were sufficient to promote HDF migration to the optimal level of PDGF-BB. Hence, our new challenge is how to reconstitute the """"""""multiple parallel signaling networks"""""""" that mediate PDGF-BB-induced HDF migration. To gain insights into this problem, we will focus on the tyrosine autophosphorylation sites in the PDGF receptor-beta (PDGFR-beta), which relay all PDGF-BB signals. We would like to gain insights into which of these phosphotyrosines constitutes the motility signaling network at the PDGFR level. We hypothesize that the parallel signaling networks originate at the PDGFR level.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM067100-08
Application #
7751203
Study Section
Surgery, Anesthesiology and Trauma Study Section (SAT)
Program Officer
Hagan, Ann A
Project Start
2003-01-01
Project End
2011-12-31
Budget Start
2010-01-01
Budget End
2011-12-31
Support Year
8
Fiscal Year
2010
Total Cost
$304,989
Indirect Cost
Name
University of Southern California
Department
Dermatology
Type
Schools of Medicine
DUNS #
072933393
City
Los Angeles
State
CA
Country
United States
Zip Code
90089
Guo, Jiacong; Jayaprakash, Priyamvada; Dan, Jian et al. (2017) PRAS40 Connects Microenvironmental Stress Signaling to Exosome-Mediated Secretion. Mol Cell Biol 37:
Dong, Hangming; Zou, Mengchen; Bhatia, Ayesha et al. (2016) Breast Cancer MDA-MB-231 Cells Use Secreted Heat Shock Protein-90alpha (Hsp90?) to Survive a Hostile Hypoxic Environment. Sci Rep 6:20605
Bhatia, Ayesha; O'Brien, Kathryn; Chen, Mei et al. (2016) Keratinocyte-Secreted Heat Shock Protein-90alpha: Leading Wound Reepithelialization and Closure. Adv Wound Care (New Rochelle) 5:176-184
Bhatia, Ayesha; O'Brien, Kathryn; Chen, Mei et al. (2016) Dual therapeutic functions of F-5 fragment in burn wounds: preventing wound progression and promoting wound healing in pigs. Mol Ther Methods Clin Dev 3:16041
Woodley, David T; Wysong, Ashley; DeClerck, Brittany et al. (2015) Keratinocyte Migration and a Hypothetical New Role for Extracellular Heat Shock Protein 90 Alpha in Orchestrating Skin Wound Healing. Adv Wound Care (New Rochelle) 4:203-212
Jayaprakash, Priyamvada; Dong, Hangming; Zou, Mengchen et al. (2015) Hsp90? and Hsp90? together operate a hypoxia and nutrient paucity stress-response mechanism during wound healing. J Cell Sci 128:1475-80
O'Brien, Kathryn; Bhatia, Ayesha; Tsen, Fred et al. (2014) Identification of the critical therapeutic entity in secreted Hsp90? that promotes wound healing in newly re-standardized healthy and diabetic pig models. PLoS One 9:e113956
Li, Wei; Tsen, Fred; Sahu, Divya et al. (2013) Extracellular Hsp90 (eHsp90) as the actual target in clinical trials: intentionally or unintentionally. Int Rev Cell Mol Biol 303:203-35
Tsen, Fred; Bhatia, Ayesha; O'Brien, Kathryn et al. (2013) Extracellular heat shock protein 90 signals through subdomain II and the NPVY motif of LRP-1 receptor to Akt1 and Akt2: a circuit essential for promoting skin cell migration in vitro and wound healing in vivo. Mol Cell Biol 33:4947-59
Sahu, Divya; Zhao, Zhengwei; Tsen, Fred et al. (2012) A potentially common peptide target in secreted heat shock protein-90ýý for hypoxia-inducible factor-1ýý-positive tumors. Mol Biol Cell 23:602-13

Showing the most recent 10 out of 13 publications