Research of heat shock protein 47 in lung fibtotic process

热休克蛋白（HSP）47作为胶原特异性分子伴侣参与多种胶原的合成/组装。HSP 47在肝硬化和其他纤维化疾病中表达上调。本实验研究了中性粒细胞嗜天青颗粒中具有抗菌和细胞毒活性的阳离子蛋白α-防御素（α-defensin）对肺成纤维细胞产生HSP 47和胶原的影响，以及HSP 47表达与肺纤维化过程的关系。首先，我们研究了α-防御素（人中性粒细胞肽（HNP）-1）对人肺成纤维细胞中HSP 47和胶原-1表达的直接影响。HNP-1 5 μg/ml诱导成纤维细胞增殖，>50 μg/ml的HNP-1浓度降低细胞活力。10 ~ 25 μg/ml的HNP-1可显著增加HSP 47和胶原-1mRNA的表达，而其蛋白释放量呈剂量依赖性增加。TGF-β还增强了这些mRNA和蛋白质的表达，吡非尼酮抑制了这些发现。在博莱霉素诱导的小鼠肺纤维化中，肺纤维化程度与HSP 47 mRNA和蛋白表达之间也观察到良好的相关性，并且吡非尼酮降低Ashcroft评分和羟脯氨酸含量。免疫组化检测肺组织细胞HSP 47、α-SMA和F4/80的表达。结果提示，α-防御素可能通过上调人肺成纤维细胞HSP 47和胶原-1直接促进肺纤维化的发生，在肺纤维化的发病机制中起重要作用，HSP 47阳性细胞可能具有促进胶原合成和释放的能力。吡非尼酮可抑制这些导致肺纤维化中细胞外基质积聚和沉积的阳性细胞。提示HSP 47和α-防御素可能成为治疗IPF的新靶点。

Heat shock protein(HSP) 47 is involved in the synthesis/assembly of various collagens as a collagen-specific molecular chaperone. HSP 47 expression has been shown upregulated in liver cirrhosis and other fibrotic diseases. We have studied the effect of α-defensin, cationic proteins with antimicrobial and cytotoxic activity in the azurophil granule of neutrophils, on the production of HSP 47 and collagen using lung fibroblasts, and the relationship between HSP47 expression and fibrotic process in murine bleomycin-induced pulmonary fibrosis. At first, we investigated the direct effect of a-defensin (human neutrophil peptide(HNP)-1) on expression of HSP47 and collagen-1 in human lung fibroblasts. HNP-1 5 μg/ml induced fibroblast proliferation and concentrations >50 μg/ml of HNP-1 reduced the cell-viability. Expression of HSP 47 and collagen-1 mRNA was significantly increased by 10 to 25 μg/ml of HNP-1, whereas their protein release increased in dose-dependent manner. TGF-β also enhanced the expression of these mRNA and proteins, and pirfenidone inhibited these findings. In murine bleomycin-induced pulmonary fibrosis, a good correlation was also observed between the degree og pulmonary fibrosis and expression of HSP47 mRNA and proteins and pirfenidone reduced the ashcroft score and hydroxyproline content. It also attenuated expression of HSP 47, a-SMA and F4/80 in lung cells by immunohistochemical study. Our results suggest that α-defensin may promote directly fibrotic process through upregulation of HSP 47 and collagen-1 in human lung fibroblasts and play an important role in the pathogenesis of pulmonary fibrosis and HSP47 positive cells may have an ability of enhanced collagen synthesis and release. Pirfenidone inhibited these positive cells responsible for the accumulation and deposition of extracellular matrix seen in pulmonary fibrosis. These findings suggest that HSP47 and α-defensin might be a new promising target for the treatment of IPF.