In vivo relative quantitative proteomics reveals HMGB 1 as a downstream mediator of oestrogen‐stimulated keratinocyte migration

It is known that oestrogen influences skin wound healing by modulating the inflammatory response, cytokine expression and extracellular matrix deposition; accelerating re‐epithelialization; and stimulating angiogenesis. To identify novel proteins associated with effects of oestrogen on keratinocyte, stable isotope labelling by amino acids in cell culture ( SILAC )‐based mass spectrometry was performed. Using SILAC , quantification of 1085 proteins was achieved. Among these proteins, 60 proteins were upregulated and 32 proteins were downregulated. Among significantly upregulated proteins, high‐mobility group protein B1 ( HMGB 1) has been further evaluated for its role in the effect of oestrogen on keratinocytes. HMGB 1 expression was strongly induced in oestrogen‐treated keratinocytes in dose‐ and time‐dependent manner. Further, HMGB 1 was able to significantly accelerate the rate of HaCaT cell migration. To determine whether HMGB 1 is involved in E2‐induced HaCaT cell migration, cells were transfected with HMGB 1 si RNA . Knockdown of HMGB 1 blocked oestrogen‐induced keratinocyte migration. Collectively, these experiments demonstrate that HMGB 1 is a novel downstream mediator of oestrogen‐stimulated keratinocyte migration.