细胞外基质
组织谷氨酰胺转胺酶
成纤维细胞
赖氨酰氧化酶
特发性肺纤维化
纤维化
细胞生物学
化学
肺纤维化
生物
病理
生物化学
体外
肺
内科学
医学
酶
作者
Christopher J Philp,Ivonne Siebeke,Debbie Clements,Suzanne Miller,Anthony Habgood,Alison E. John,Vidya Navaratnam,Richard Hubbard,Gisli Jenkins,Simon R. Johnson
标识
DOI:10.1165/rcmb.2016-0379oc
摘要
Idiopathic pulmonary fibrosis (IPF) is characterized by accumulation of extracellular matrix (ECM) proteins and fibroblast proliferation. ECM cross-linking enzymes have been implicated in fibrotic diseases, and we hypothesized that the ECM in IPF is abnormally cross-linked, which enhances fibroblast growth and resistance to normal ECM turnover. We used a combination of in vitro ECM preparations and in vivo assays to examine the expression of cross-linking enzymes and the effect of their inhibitors on fibroblast growth and ECM turnover. Lysyl oxidase-like 1 (LOXL1), LOXL2, LOXL3, and LOXL4 were expressed equally in control and IPF-derived fibroblasts. Transglutaminase 2 was more strongly expressed in IPF fibroblasts. LOXL2-, transglutaminase 2–, and transglutaminase-generated cross-links were strongly expressed in IPF lung tissue. Fibroblasts grown on IPF ECM had higher LOXL3 protein expression and transglutaminase activity than those grown on control ECM. IPF-derived ECM also enhanced fibroblast adhesion and proliferation compared with control ECM. Inhibition of lysyl oxidase and transglutaminase activity during ECM formation affected ECM structure as visualized by electron microscopy, and it reduced the enhanced fibroblast adhesion and proliferation of IPF ECM to control levels. Inhibition of transglutaminase, but not of lysyl oxidase, activity enhanced the turnover of ECM in vitro. In bleomycin-treated mice, during the postinflammatory fibrotic phase, inhibition of transglutaminases was associated with a reduction in whole-lung collagen. Our findings suggest that the ECM in IPF may enhance pathological cross-linking, which contributes to increased fibroblast growth and resistance to normal ECM turnover to drive lung fibrosis.
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