Regulation of Proliferation, Motility, and Contractility of Human Endometrial Stromal Cells by Platelet-Derived Growth Factor

To evaluate the involvement of platelet-derived growth factor (PDGF) isoforms (PDGF-ΑΑ, PDGF-AB, and PDGF-BB) on endometrial tissue remodeling during the perimenstrual period, we investigated the effects of PDGF on the proliferation, motility, invasiveness, and contractility of cultured human endometrial stromal cells (ESC) using a modified methylthiazoletetrazolium assay, a 5-bromo-2′-deoxyuridine incorporation assay, an in vitro wound repair assay, a chemotactic migration assay, a Transwell invasion assay, and a collagen gel contraction assay. All three isoforms of PDGF significantly enhanced the cell proliferation, DNA synthesis, and in vitro wound repair of ESC. Chemotactic migration assay, Transwell invasion assay, and collagen gel contraction assay demonstrated that the PDGF isoforms significantly stimulated both the motility of ESC and the collagen gel contractility of ESC. PDGF-BB showed the strongest effects on these cellular functions of ESC. The present study suggested that PDGF isoforms may promote endometrial tissue repair by enhancing the proliferation and expansion of ESC, stimulating ESC migration, and stimulating the contraction of the collagen gel matrix by ESC. By regulating ESC function during the perimenstrual period, PDGF may help to protect the endometrium from extensive fibrosis and scarring.

Modulation of PDGF-C and PDGF-D expression during bleomycin-induced lung fibrosis

PDGF isoforms are a family of polypeptides that bind to cell surface receptors and induce fibroblast proliferation and chemotaxis. The PDGF-A and -B chain isoforms have been implicated in fibroproliferative lung injury in animal models and in human disease. Two recently recognized PDGF polypeptides, PDGF-C and -D, differ from the PDGF-A and -B isoforms in that they require proteolytic cleavage before they can bind and activate the PDGF receptors. Our findings demonstrate that administration of bleomycin to murine lungs leads to a significant increase in PDGF-C mRNA expression and a significant decrease in PDGF-D mRNA expression. PDGF-C expression was localized to areas of lung injury by in situ hybridization, and PDGF-C expression was not upregulated in the lungs of BALB/c mice that are resistant to bleomycin-induced lung fibrosis. Moreover, there is in vivo phosphorylation of the PDGF-receptor that binds PDGF-C in response to bleomycin administration. These observations strongly suggest a role for PDGF-C in bleomycin-induced pulmonary fibrosis.