Green Jenna, Endale Mehari, Auer Herbert, Perl Anne-Karina T
1 Perinatal Institute, Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; and.
2 Functional GenOmics Consulting, Palleja, Spain.
Am J Respir Cell Mol Biol. 2016 Apr;54(4):532-45. doi: 10.1165/rcmb.2015-0095OC.
Epithelial-mesenchymal cell interactions and factors that control normal lung development are key players in lung injury, repair, and fibrosis. A number of studies have investigated the roles and sources of epithelial progenitors during lung regeneration; such information, however, is limited in lung fibroblasts. Thus, understanding the origin, phenotype, and roles of fibroblast progenitors in lung development, repair, and regeneration helps address these limitations. Using a combination of platelet-derived growth factor receptor α-green fluorescent protein (PDGFRα-GFP) reporter mice, microarray, real-time polymerase chain reaction, flow cytometry, and immunofluorescence, we characterized two distinct interstitial resident fibroblasts, myo- and matrix fibroblasts, and identified a role for PDGFRα kinase activity in regulating their activation during lung regeneration. Transcriptional profiling of the two populations revealed a myo- and matrix fibroblast gene signature. Differences in proliferation, smooth muscle actin induction, and lipid content in the two subpopulations of PDGFRα-expressing fibroblasts during alveolar regeneration were observed. Although CD140α(+)CD29(+) cells behaved as myofibroblasts, CD140α(+)CD34(+) appeared as matrix and/or lipofibroblasts. Gain or loss of PDGFRα kinase activity using the inhibitor nilotinib and a dominant-active PDGFRα-D842V mutation revealed that PDGFRα was important for matrix fibroblast differentiation. We demonstrated that PDGFRα signaling promotes alveolar septation by regulating fibroblast activation and matrix fibroblast differentiation, whereas myofibroblast differentiation was largely PDGFRα independent. These studies provide evidence for the phenotypic and functional diversity as well as the extent of specificity of interstitial resident fibroblasts differentiation during regeneration after partial pneumonectomy.
上皮-间充质细胞相互作用以及控制正常肺发育的因子是肺损伤、修复和纤维化的关键因素。许多研究调查了肺再生过程中上皮祖细胞的作用和来源；然而，关于肺成纤维细胞的此类信息有限。因此，了解成纤维细胞祖细胞在肺发育、修复和再生中的起源、表型及作用有助于克服这些局限性。我们结合使用血小板衍生生长因子受体α-绿色荧光蛋白（PDGFRα-GFP）报告基因小鼠、微阵列、实时聚合酶链反应、流式细胞术和免疫荧光，对两种不同的间质驻留成纤维细胞，即肌成纤维细胞和基质成纤维细胞进行了表征，并确定了PDGFRα激酶活性在肺再生过程中调节其激活的作用。对这两个群体的转录谱分析揭示了肌成纤维细胞和基质成纤维细胞的基因特征。观察到在肺泡再生过程中，表达PDGFRα的成纤维细胞的两个亚群在增殖、平滑肌肌动蛋白诱导和脂质含量方面存在差异。尽管CD140α(+)CD29(+)细胞表现为肌成纤维细胞，但CD140α(+)CD34(+)细胞表现为基质成纤维细胞和/或脂成纤维细胞。使用抑制剂尼洛替尼和显性激活的PDGFRα-D842V突变来增加或降低PDGFRα激酶活性，结果表明PDGFRα对基质成纤维细胞的分化很重要。我们证明，PDGFRα信号通过调节成纤维细胞激活和基质成纤维细胞分化来促进肺泡间隔形成，而肌成纤维细胞的分化在很大程度上不依赖于PDGFRα。这些研究为部分肺切除术后再生过程中间质驻留成纤维细胞分化的表型和功能多样性以及特异性程度提供了证据。
