Chronic Wound Fluid Suppresses Proliferation of Dermal Fibroblasts Through a Ras-Mediated Signaling Pathway

Abstract

Wound fluid collected from chronic venous leg ulcers (chronic wound fluid (CWF)) has been shown to inhibit the growth of dermal fibroblasts by interfering with cell-cycle progression from G1 into S phase. Specifically, CWF was shown to downregulate the levels of hyperphosphorylated retinoblastoma tumor-suppressor gene (Rb) and cyclin D1, known to be critical for entering the S phase of the cell cycle. To further elucidate the effects of CWF, a Ras-mediated signaling pathway involving the mitogen-activated protein kinase kinase (MEK), known to modulate the expression of these cell-cycle-regulatory proteins, was examined. Transient transfection of dermal fibroblasts with constitutively active Ras abrogated the growth suppressive effects of CWF on hyperphosphorylated Rb (ppRb) and cyclin D1. In contrast, an MEK inhibitor PD 98059 mimicked the effects of CWF on these cell-cycle-regulatory proteins. Concurrent treatment with PD 98059 and CWF produced additive effects. Taken together, these results suggest that CWF inhibits the growth of dermal fibroblasts at least in part by decreasing the level of active Ras, resulting in decreased levels of ppRb and cyclin D1. Therefore, a Ras-dependent signaling pathway may mediate the growth inhibitory effect of CWF, and reconstitution of Ras activity may overcome this growth inhibitory effect.

Characterization of the acute temporal changes in excisional murine cutaneous wound inflammation by screening of the wound-edge transcriptome

“…Consistently we noted that components of this pathway were upregulated during the intermediary phase (12-96 h) after wounding. Genes upregulated in response to wounding in the late phase (48 -96 h) represented the cell cycle pathway, which is known to be implicated in additional cell supply during the process of tissue repair (14,68). Cutaneous wound repair is associated with changes in purine metabolism (58).…”

A CXCL5- and bFGF-dependent effect of PDGF-B-activated fibroblasts in promoting trafficking and differentiation of bone marrow-derived mesenchymal stem cells

“…However, our herein reported effects on BM-MSCs have not been previously studied. The importance of PDGF-B-activated resident wound fibroblasts is underscored by reports showing that decreased PDGF-B levels [19], incomplete fibroblast activation, dysmotility and early senescence occur in lower extremity chronic non-healing wounds, resulting in growth factor imbalance and non-healing [31][32][33]. Our findings may provide guidance for the development of effective therapeutic protocols in the treatment chronic and diabetic wounds as the effects of PDGF-B and its downstream mediators, CXCL5 and bFGF, identified in this study are highly relevant to the wound-healing cascade.…”

Wound Fluid Diagnostics in Diabetic Foot Ulcers

“…In the past, this particular technique has frequently been modified. Protocols describing the extraction of fluids directly from dressings have been reported multiple times (Fivenson et al 1997;Seah et al 2005). For example, wound exudate trapped in a foam dressing has been obtained by squeezing the dressing material through a syringe (Seah et al 2005).…”