Hmgb1 Promotes Wound Healing of 3T3 Mouse Fibroblasts via Rage-Dependent ERK1/2 Activation

Abstract

HMGb1 is a nuclear protein playing a role in DNA architecture and transcription. This protein has also been shown to function as a cytokine and to stimulate keratinocyte scratch wound healing. Due to the importance of finding new wound healing molecules, we have studied the effects of HMGb1 on fibroblasts, another major skin cell type, using the NIH 3T3 line. HMGb1 expression in these cells was assessed by Western blot, while its nuclear localization was pointed out by confocal immunofluorescence. HMGb1-induced cell proliferation with a maximum at a concentration of 10 nM, and such a dose also stimulated cell migration and scratch wound healing. Western blot analysis showed that HMGb1 activates ERK1/2, while the use of an anti-RAGE receptor-blocking antibody and of the selective MEK1/2 inhibitor PD98059 blocked ERK1/2 activation and wound healing responses to HMGb1. Taken together data show that HMGb1 promotes 3T3 fibroblast wound healing by inducing cell proliferation and migration, and that this occurs through the activation of the RAGE/MEK/ERK pathway. In conclusion, HMGb1 seems a good candidate for the development of medical treatments to be used on chronic or severe wounds.

HMGB1 in renal ischemic injury

“…Kohno et al (35) supported Limana and colleagues' reports in which blockade of HMGB1 after postmyocardial infarction resulted in impairment of the infarct healing process and marked hypertrophy of the noninfarcted surrounding areas. HMGB1 has also been found to be involved in the healing of other injured tissues, such as skin wounds (54,55,65). Tamai et al (65) demonstrated HMGB1 has the ability to mobilize PDGFR␣-positive (and lineage negative) cells from the bone marrow to regenerate injured skin epithelial cells.…”

“…In a model of IRI, neutralizing antibodies against HMGB1 offered significant protection against renal IRI damage, as was demonstrated with a reduction in tubular apoptosis, serum creatinine, blood urea nitrogen (BUN), TNF-␣ expression, and pathologic injury (37,78). However, not all of HMGB1's downstream effects are detrimental as various injury models have strongly implicated HMGB1 in regeneration and repair after tissue damage (2,10,35,38,43,48,54,55,60,75,83). Once released into the circulation, HMGB1 induces migration, proliferation, and homing of vascular-associated stem cells to sites of injury (10,46) and regeneration of epithelia by mobilization of platelet-derived growth factor receptor ␣-positive (Lin-/PDGFR␣ϩ) bone marrow cells (65).…”

Advanced glycation end products induce a prothrombotic phenotype in mice via interaction with platelet CD36

“…To assess the role of RAGE in platelet-AGE binding, we preincubated wt platelets with 10 g/mL of a well-characterized blocking mAb to RAGE. 22 As shown in Figure 2B, blocking RAGE had no significant effect on biotin-AGE-BSA binding. These results strongly suggest that platelet-AGE binding is mediated primarily by CD36.…”

Necrotic cell-derived high mobility group box 1 attracts antigen-presenting cells but inhibits hepatocyte growth factor-mediated tropism of mesenchymal stem cells for apoptotic cell death

“…On the other hand, RAGE-mediated chemoattractive activity of HMGB1 has been documented for other stem and progenitor cells, including endothelial progenitor cells, 37 as well as for progeny of MSC-like smooth muscle cells 47 and fibroblasts. 48 Whether such differences in the migratory responsiveness of MSC to HMGB1 are possibly due to subpopulations, the presence of certain co-factors or differences in culture conditions needs to be determined.…”