S49 The role of platelet-derived TGFß in pulmonary fibrosis
S49 The role of platelet-derived TGFß in pulmonary fibrosis
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S49 血小板衍生的 TGFα 在肺纤维化中的作用
DOI：
10.1136/thoraxjnl-2016-209333.55
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发表时间：
2016
期刊：
影响因子：
10
通讯作者：
Chong D
中科院分区：
文献类型：
--
作者：
Chong D
肺纤维化(PF)的特征是创面愈合异常，包括成纤维细胞增殖、肌成纤维细胞分化和细胞外基质沉积增加。转化生长因子β是纤维化疾病的重要驱动力，但该细胞因子在肺间质纤维化中的来源尚不明确。血小板可以释放大量转化生长因子β，我们等人已发现特发性肺纤维化患者肺内有血小板沉积，但这些细胞在肺纤维化中的作用尚不清楚。假设我们认为，血小板聚集和释放转化生长因子β有助于纤维增殖性肺疾病创面的异常愈合。基因敲除(KO)小鼠和野生型(WT)仔鼠采用口咽部注射博莱霉素诱导肺纤维化的实验模型。分别于给药后第6、21、28天取肺组织和支气管肺泡灌洗液(BALF)。结果：体外实验表明，血小板源性转化生长因子β对中性粒细胞有较强的趋化作用，在1 ng/ml时作用最强。体内：博莱霉素治疗6天后，WT和KO动物肺和肺泡灌洗液中的中性粒细胞和巨噬细胞均显著增加。WT和KO小鼠之间的细胞百分比或细胞总数没有显著差异。在博莱霉素治疗后的第21天，通过显微CT检查，肺部出现了大的纤维性病变。博莱霉素治疗的KO小鼠表现出比WT动物(26.9%比19.6%)更弱的纤维化反应，尽管没有达到统计学意义。在治疗后28天的创面愈合阶段，通过显微CT分析，WT和KO动物的纤维化程度非常相似(9.56%比9.84%)。结论我们的数据表明，尽管在体外具有强大的中性粒细胞趋化作用，但在我们的PF动物模型的炎症或消退阶段，血小板衍生的转化生长因子β在活体内不是主要的驱动力，但可能有助于纤维化疾病的发展。这将是进一步研究的主题。
BackgroundPulmonary Fibrosis (PF) is characterised by abnormal wound healing involving fibroblast proliferation, myofibroblast differentiation and increased extracellular matrix deposition. TGFβ is an important driving force in fibrotic disease, however the source of this cytokine in PF is ill-defined. Platelets can release large amounts of TGFβ, and we, and others, have shown platelet deposition in the lungs of patients with idiopathic pulmonary fibrosis (IPF), although the role of these cells in PF is unknown.HypothesisWe propose that platelet aggregation and release of platelet-derived TGFβ contributes to the aberrant wound healing in fibroproliferative lung disease.MethodsWe used a double-transgenic mouse with megakaryocytic-specific deletion of TGFβ (PF4-Cre+/Tgfb1fl) and hence platelets lacking TGFβ. Knockout (KO) mice and wildtype (WT) littermate controls were subjected to the experimental model of lung fibrosis induced by oropharyngeal bleomycin administration. Lung tissue and broncho-alveolar lavage fluid (BALF) were investigated at 6, 21 or 28 days post-bleomycin. Complementaryin vitrostudies were performed on isolated neutrophils to investigate the effects of platelet-derived TGFβ in chemotaxis assays.ResultsIn vitro: Platelet-derived TGFβ was shown to be a potent neutrophil chemoattractant with maximal effect at 1ng/ml.In vivo: At 6 days after bleomycin treatment, neutrophils and macrophages were significantly elevated in the lung and BALF in both WT and KO animals as measured by flow cytometric analysis. No significant difference in the percentage or total cell numbers was found between WT or KO mice. At 21 days post-bleomycin, the lungs developed large fibrotic lesions when examined by micro-CT. Bleomycin-treated KO mice exhibited an attenuated fibrotic response compared with WT animals (26.9 vs. 19.6%), although not reaching statistical significance. During the wound resolution phase at 28 days post treatment, the degree of fibrosis between WT and KO animals was very similar (9.56 vs. 9.84%) as determined by micro-CT analysis.ConclusionOur data suggest that despite being a potent neutrophil chemoattractantin vitro, platelet-derived TGFβin vivois not a major driving force during the inflammatory or resolution phases of our PF animal model, but may contribute to the development of fibrotic disease. This will be the subject of further study.