Platelet-derived transforming growth factor-β1 promotes keratinocyte proliferation in cutaneous wound healing.

Deborah L.W Chong,Sarah Trinder,Myriam Labelle,Joanna C Porter,Manuel Rodriguez‐Justo,Sian Hughes,Chris J Scotton,Alan M Holmes

doi:10.1002/term.3022

Abstract

Platelets are a recognised potent source of transforming growth factor‐β1 (TGFβ1), a cytokine known to promote wound healing and regeneration by stimulating dermal fibroblast proliferation and extracellular matrix deposition. Platelet lysate has been advocated as a novel personalised therapeutic to treat persistent wounds, although the precise platelet‐derived growth factors responsible for these beneficial effects have not been fully elucidated. The aim of this study was to investigate the specific role of platelet‐derived TGFβ1 in cutaneous wound healing. Using a transgenic mouse with a targeted deletion of TGFβ1 in megakaryocytes and platelets (TGFβ1fl/fl.PF4‐Cre), we show for the first time that platelet‐derived TGFβ1 contributes to epidermal and dermal thickening and cellular turnover after excisional skin wounding. In vitro studies demonstrate that human dermal fibroblasts stimulated with platelet lysate containing high levels of platelet‐derived TGFβ1 did not exhibit enhanced collagen deposition or proliferation, suggesting that platelet‐derived TGFβ1 is not a key promoter of these wound healing processes. Interestingly, human keratinocytes displayed enhanced TGFβ1‐driven proliferation in response to platelet lysate, reminiscent of our in vivo findings. In summary, our novel findings define and emphasise an important role of platelet‐derived TGFβ1 in epidermal remodelling and regeneration processes during cutaneous wound healing.

Highlights

As transforming growth factor-β1 (TGFβ1) has previously been demonstrated to increase over time in wounded skin (Ishida, Kondo, Takayasu, Iwakura, & Mukaida, 2004) and along with our observations of increased in vivo Ki-67 expression as a marker of cell proliferation, we investigated whether platelet-derived TGFβ1 can induce functional changes in specific dermal cells
TGFβ1- or Platelet lysate (PL)-induced proliferative effects were significantly decreased when keratinocytes were pretreated with an ALK5 inhibitor to block downstream TGFβ1 receptor signalling prior to stimulation with PL (Figure 2e). This suggests that platelet-derived TGFβ1 significantly contributes to primary human keratinocyte proliferation
In contrast to other in vitro studies (Ranzato et al, 2009), we did not observe any differences in proliferation or collagen deposition when human dermal fibroblasts were stimulated with PL, even at varying dilutions of PL and time points (Figure S4)

Summary

Introduction

H&E histological analysis of the wound after 14 days revealed significantly thinner epidermis and dermis in TGFβ1fl/fl.PF4-Cre animals compared with controls (Figure 1c,d). Dermal and epidermal layers in unwounded skin surrounding the wound area were similar between control and TGFβ1fl/fl.PF4-Cre mice (Figure 1e).

Objectives

Results

Conclusion