HMGb1 promotes scratch wound closure of HaCaT keratinocytes via ERK1/2 activation

Abstract

HMGb1 is a DNA-binding protein whose role as an extracellular cytokine in inflammation and tissue regeneration has also been reported. Given the importance of keratinocytes in wound healing, we have studied the mechanism of action of HMGb1 on HaCaT keratinocytes during in vitro scratch wound repair. Western blot and confocal immunofluorescence microscopy showed that these cells express significant amounts of HMGb1, that the protein is prevalently localized in the nucleus, and that its release by cells is negligible. Western blot also showed that these cells express the HMGb1 receptor RAGE. Cell exposure to HMGb1 in the absence of serum resulted in a stimulation of cell proliferation and ERK1/2 activation. HMGb1 also accelerated the wound closure of scratch wounded cells and promoted cell migration, as evaluated by a transwell assay. The HMGb1-induced increases of cell proliferation, cell migration, and wound closure were abolished by the MEK inhibitor PD98059. Taken together, data show that, although HMGb1 is not released by HaCaT, when applied exogenously it can induce a marked increase of the wound repair of these cells. Data also suggest that HMGb1 acts via the RAGE/MEK/ERK pathway. These results bring scientific support to the potential application of HMGb1 in regenerative medicine.

The Roles of Growth Factors in Keratinocyte Migration

“…HMGB1 induces KC proliferation and migration via an unknown receptor. 84,85 HMGB1 activates the ERK1/2 pathway in KCs, and MEK inhibitors block the proliferative effect of HMGB1. 84 HMGB1 treatment increases the rate of wound closure in diabetic mice and retards the rate of wound closure in normal mice.…”

“…84,85 HMGB1 activates the ERK1/2 pathway in KCs, and MEK inhibitors block the proliferative effect of HMGB1. 84 HMGB1 treatment increases the rate of wound closure in diabetic mice and retards the rate of wound closure in normal mice. 85 Therefore, HBGB1 functions as both a mitogenic and motogenic factor for KCs.…”

Messengers without Borders

“…68 It is involved in the healing of injured tissues, such as myocardium and skin wounds. [69][70][71][72] In addition, HMGB1 is reported to possess proangiogenic activity. [73][74][75][76] Its ability to promote proliferation, migration, and differentiation of several cell types, particularly those involved in angiogenesis, prompted us to examine the ability of HMGB1 to mobilize EPCs from the bone marrow.…”

HMGB1 blockade attenuates experimental autoimmune myocarditis and suppresses Th17‐cell expansion

“…HMGB1 binds to the endogenous receptor for advanced glycation endproducts [7], exogenous toll-like receptor 2/4/9 (TLR2/4/9) [8,9], and CD24/Siglec-10 [10], and induces the expression of proinammatory cytokines, chemokines, and adhesion molecules [3,6]. Although, HMGB1 was initially thought to be a late mediator of sepsis, recent data also indicated that HMGB1 is associated with many other pathological conditions, such as autoimmune disease [11], cancer [12][13][14], trauma, ischemia-reperfusion injury [15,16], tissue repair and regeneration [17,18], and cardiovascular diseases [19]. Furthermore, HMGB1 has restorative effects on CD4 1 T-helper cell modulation [20].…”

“…thought to be a late mediator of sepsis, recent data also indicated that HMGB1 is associated with many other pathological conditions, such as autoimmune disease [11], cancer [12][13][14], trauma, ischemia-reperfusion injury [15,16], tissue repair and regeneration [17,18], and cardiovascular diseases [19]. Furthermore, HMGB1 has restorative effects on CD4 1 T-helper cell modulation [20].…”