title: Light-Emitting Diode Irradiation (640 nm) Regulates Keratinocyte Migration and Cytoskeletal Reorganization Via Hypoxia-Inducible Factor-1α.
abstract: OBJECTIVE
  The objective of this study was to determine the effect of light-emitting diode (LED) irradiation on the migration and proliferation of keratinocytes.
  
  
  BACKGROUND
  Keratinocytes play a key role in re-epithelialization during wound healing; it is speculated that low-level LED therapy might improve keratinocyte migration and proliferation.
  
  
  METHODS
  Human keratinocyte cells (HKCs) were isolated from child or adult foreskins and irradiated with LED light with a wavelength of 640 nm and a dosage of 12 or 24 J/cm(2). Cell motility, migration, and proliferation were examined using live cell imaging, scratch assay, and a colorimetric cell counting assay, respectively. Hypoxia-inducible factor-1α (HIF-1α) protein levels were analyzed by using Western blotting. Filamentous actin (F-actin) was stained by phalloidin. YC-1 [3-(5-hydroxymethyl-2-furyl)-1-benzylindazole] was used as an HIF-1 inhibitor, and CoCl2 (cobalt chloride) and DMOG (dimethyloxaloyl glycine) are HIF-1α activators.
  
  
  RESULTS
  LED irradiation significantly promoted cell motility and migration, but did not significantly influence cell proliferation in HKCs. Furthermore, LED irradiation resulted in a reorganization of cellular F-actin and a dramatic upregulation of HIF-1α expression. Suppression of HIF-1α using the compound YC-1 prevented reorganization of the actin cytoskeleton following LED irradiation, suggesting that the effect of LED irradiation on the cytoskeleton is mediated through HIF-1α. Conversely, chemical activation of HIF-1α via DMOG or CoCl2 resulted in a reorganization of F-actin.
  
  
  CONCLUSIONS
  LED irradiation may increase keratinocyte migration via HIF-1α-dependent cytoskeletal reorganization.
authors.affiliation: 1 The Second Military Medical University of People's Liberation Army , Shang Hai, P.R. China .|2 Department of Plastic Surgery, General Hospital of Guangzhou Military Command , PLA, Guangzhou, P.R. China .
authors.forename: Chong
authors.initials: C
authors.lastname: Huang
authors.affiliation: 2 Department of Plastic Surgery, General Hospital of Guangzhou Military Command , PLA, Guangzhou, P.R. China .
authors.forename: Sheng Lin
authors.initials: SL
authors.lastname: Qian
authors.affiliation: 3 Department of Oncology, General Hospital of Guangzhou Military Command , PLA, Guangzhou, P.R. China .
authors.forename: Li Yue
authors.initials: LY
authors.lastname: Sun
authors.affiliation: 2 Department of Plastic Surgery, General Hospital of Guangzhou Military Command , PLA, Guangzhou, P.R. China .
authors.forename: Biao
authors.initials: B
authors.lastname: Cheng
mesh_terms: D000328:Adult; D015153:Blotting, Western; D002465:Cell Movement / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002648:Child; D003035:Cobalt / Q000494:pharmacology; D003599:Cytoskeleton / Q000528:radiation effects; D052816:Foreskin / Q000166:cytology; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D007191:Indazoles / Q000494:pharmacology; D015603:Keratinocytes / Q000378:metabolism* / Q000528:radiation effects*; D028022:Low-Level Light Therapy; D008297:Male; D015854:Up-Regulation
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D007191:Indazoles; C000613347:dimethyloxallyl glycine; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D003035:Cobalt; C018021:cobaltous chloride; D005998:Glycine