title: Pulmonary microvascular endothelial cells from bleomycin-induced rats promote the transformation and collagen synthesis of fibroblasts.
abstract: Accumulation and activation of myofibroblasts are the hallmark of progressive pulmonary fibrosis, and the resident fibroblasts are the major source of myofibroblasts. However, the key factors involved in the transformation of fibroblasts are unknown. Pulmonary microvascular endothelial cells (PMVECs), major effector cells against pathogenesis in early stages of the disease, can secrete cytokines to induce the differentiation of mesenchymal cells. We speculated that PMVECs could secrete pro-fibrotic cytokines and promote the transformation of fibroblasts into myofibroblasts. Accordingly, we established a co-culture system with PMVECs and fibroblasts to examine the specific transformation and collagen synthesis of the co-cultured fibroblasts by FACS and Western blot, prior to and after treatment with neutralizing antibodies against transforming growth factor-beta1 (TGF-β1) and connective tissue growth factor (CTGF). We also analyzed expression of TGF-β1 and CTGF in PMVECs. The synthesis and secretion of TGF-β1 and CTGF protein were up-regulated in PMVECs isolated from bleomycin (BLM)-treated rats, most prominently at 7 days post-instillation. We showed that the PMVECs isolated from BLM-induced rats could induce the transformation of normal fibroblasts and their secretion of collagen I, which was inhibited by both neutralizing anti-TGF-β1 and anti-CTGF antibodies. Therefore, up-regulation of TGF-β1 and CTGF in PMVECs plays an important role in activation, transformation, and collagen synthesis of fibroblasts; in particular, these effects in PMVECs are likely to be the key factors for activation and stimulation of static fibroblasts in lung interstitium in early stages of pulmonary fibrosis disease.
authors.affiliation: Department of Radiology, Tangdu Hospital, The Fourth Military Medical University, Xinshi Road, Xi'an, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yin
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Nan
authors.forename: Wen-Hu
authors.initials: WH
authors.lastname: Zhang
authors.forename: Lin-Feng
authors.initials: LF
authors.lastname: Yan
authors.forename: Guang-Bin
authors.initials: GB
authors.lastname: Cui
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Huang
authors.forename: Jing-Guo
authors.initials: JG
authors.lastname: Wei
mesh_terms: D000818:Animals; D001761:Bleomycin / Q000494:pharmacology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003094:Collagen / Q000096:biosynthesis*; D055513:Connective Tissue Growth Factor / Q000096:biosynthesis; D004730:Endothelium, Vascular / Q000166:cytology*; D005347:Fibroblasts / Q000187:drug effects*; D008168:Lung / Q000098:blood supply* / Q000187:drug effects; D008297:Male; D055806:Microvessels / Q000166:cytology; D058628:Myofibroblasts / Q000187:drug effects; D011658:Pulmonary Fibrosis / Q000139:chemically induced / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D053773:Transforming Growth Factor beta1 / Q000096:biosynthesis; D015854:Up-Regulation
chemical_list: D053773:Transforming Growth Factor beta1; D001761:Bleomycin; D055513:Connective Tissue Growth Factor; D003094:Collagen