title: Negative pressure accelerated monolayer keratinocyte healing involves Cdc42 mediated cell podia formation.
abstract: BACKGROUND
  Negative-pressure wound therapy (NPWT) is developed to facilitate wound healing at controlled subatmospheric pressures in modern medicine. Molecular mechanism for this therapy is still undefined.
  
  
  OBJECTIVE
  This study highlights the localization and time-course of the cell division control protein 42 (Cdc42) in the cell membrane at ambient pressure (AP) and negative pressures of 75mmHg (NP75), 125mmHg (NP125) and 175mmHg (NP175).
  
  
  METHODS
  The prepared cells were cultured in a negative pressure incubator with the same O2 and CO2 tensions at the four different pressures. The effective time, complete wound closure time, cell volume, cell viability, and the fluorescence of proliferating cell nuclear antigens (PCNA) and actins were evaluated in cells at different pressures. Wound-healing process and Cdc42 fluorescence were examined in cells with the knockdown of Cdc42. Cdc42 pathway proteins in cell membranes were analyzed after incubation at different pressures for 6 and 12h.
  
  
  RESULTS
  The cells at NP125 had less wound closure time and obvious cell podia. Similar PCNA fluorescent intensity was observed in cells at different pressures. The Cdc42, neural Wiskott-Aldrich syndrome protein, and actin expression increased significantly (p<0.05) in plasma membranes of cells at NP125 for 12h. The knockdown of active Cdc42 resulted in the absence of Cdc42 expression at the cell leading edge.
  
  
  CONCLUSIONS
  The activation and localization of Cdc42 pathway proteins in the cell membrane are involved in the cell podia formation in keratinocytes at NP125. NPWT may facilitate cell migration to accelerate wound healing.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, No. 222 Maijin Road, Keelung, Taiwan. steele0618@gmail.com
authors.forename: Chih-Chin
authors.initials: CC
authors.lastname: Hsu
authors.forename: Shu-Er
authors.initials: SE
authors.lastname: Chow
authors.forename: Carl Pai-Chu
authors.initials: CP
authors.lastname: Chen
authors.forename: Wen-Chung
authors.initials: WC
authors.lastname: Tsai
authors.forename: Jong-Shyan
authors.initials: JS
authors.lastname: Wang
authors.forename: Shin-Ying
authors.initials: SY
authors.lastname: Yu
authors.forename: Sheng-Chi
authors.initials: SC
authors.lastname: Lee
mesh_terms: D000199:Actins / Q000378:metabolism; D018929:Cell Culture Techniques / Q000295:instrumentation; D002460:Cell Line; D002465:Cell Movement; D022081:Cell Surface Extensions / Q000201:enzymology* / Q000473:pathology; D002470:Cell Survival; D006801:Humans; D007185:Incubators; D015603:Keratinocytes / Q000201:enzymology* / Q000473:pathology; D054843:Negative-Pressure Wound Therapy; D058105:Polymerization; D011312:Pressure; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D034622:RNA Interference; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D014945:Wound Healing; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D000199:Actins; D018809:Proliferating Cell Nuclear Antigen; D020764:cdc42 GTP-Binding Protein