HIF-1α is a key molecule for the progression of EMT-mediated renal fibrosis

HIF-1α是EMT介导的肾纤维化进展的关键分子

• 批准号: 15590854
• 负责人: IWANO Masayuki
• 金额: $ 1.98万
• 依托单位: Nara Medical University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15590854/
• 关键词: interstitial fibrosis; HIF-1α; VHL; FSP1; hypoxia

Epithelial-mesenchymal transition(EMT) plays a central role in mediating tubulointerstitial fibrosis. In human biopsy samples, tubular epithelial cells(TECs) surrounding the fibrotic area expressed fibroblast specific protein 1(FSP1), although TECs positive for α smooth muscle actin were very rare. Therefore, it is essential to examine FSP1 expression in TECs for the detection of EMT in renal fibrosis. Previous studies have implicated that chronic hypoxia is the main contributor to the development and progression of tubulointerstitial fibrosis. In this study, we examined whether hypoxia could be a factor mediating EMT in vitro and in vivo. We established the method to detect EMT in vitro, using primary culture of TECs genetically marked by Cre-loxP system. TECs started to elongate after hypoxic exposure and became fibroblast-like cells morphologically at 5 days after hypoxia. Immunocytochemistry revealed that more than 40% of TECs expressed FSP1 at 5 days after hypoxia. The chief mediator of hypoxic response is hypoxia-inducible factor 1(HIF-1), and its oxygen-sensitive component HIF-1α which is promptly degraded by a kind of ubiquitin ligase, the von Hippel-Lindau tumor suppressor (VHL) in normoxia. To study more directly whether HIF-1α functions in renal fibrosis in vivo, we generated a mouse line with epithelium-targeted expression of VHL gene (constitutively active HIF-1), using Cre-loxP-mediated recombination. Tubulointerstitial fibrosis was induced by unilateral ureteral obstruction(UUO). Both obstructed and unobstructed kidneys were harvested for immunohistochemistry 8 days after UUO. FSP1 positive cell numbers increased significantly in unobstructed kidneys of VHL mutant mice compared with wild type mice. These results strongly suggest that HIF-1α activates tissue fibroblasts in renal fibrosis via the induction of epithelial-mesenchymal transition(EMT).

上皮-间质转化（EMT）在介导肾小管间质纤维化中起重要作用。在人类活检样本中，纤维化区域周围的肾小管上皮细胞（TEC）表达成纤维细胞特异性蛋白1（FSP 1），尽管α平滑肌肌动蛋白阳性的TEC非常罕见。因此，检测TEC中FSP 1的表达对于检测肾纤维化中的EMT是必要的。以往的研究表明慢性缺氧是肾小管间质纤维化发生和发展的主要因素。在这项研究中，我们研究是否缺氧可能是一个因素介导的EMT在体外和体内。本研究利用Cre-loxP系统标记的TECs原代培养，建立了体外检测EMT的方法。TECs在缺氧暴露后开始伸长，并在缺氧后5天成为成纤维细胞样细胞。免疫细胞化学显示，缺氧后5天，超过40%的TECs表达FSP 1。缺氧反应的主要介质是缺氧诱导因子1（hypoxia-inducible factor 1，HIF-1）及其氧敏感组分HIF-1α，HIF-1α在常氧条件下可被一种泛素连接酶--von Hippel-Lindau肿瘤抑制因子（von Hippel-Lindau tumor suppressor，VHL）迅速降解。为了更直接地研究HIF-1α是否在体内肾纤维化中起作用，我们使用Cre-loxP介导的重组产生了上皮靶向表达VHL基因（组成型活性HIF-1）的小鼠系。单侧输尿管梗阻（UUO）诱导肾小管间质纤维化。梗阻和通畅的肾脏均在UUO后8天收获用于免疫组织化学。与野生型小鼠相比，VHL突变小鼠通畅肾脏中FSP 1阳性细胞数显著增加。这些结果有力地表明，HIF-1α通过诱导上皮-间质转化（EMT）激活肾纤维化中的组织成纤维细胞。

项目成果

Fibroblast-specific protein 1 is a specific prognostic marker for renal survival in patients with IgA nephropathy

成纤维细胞特异性蛋白 1 是 IgA 肾病患者肾脏存活的特异性预后标志物

• 发表时间: 2005
• 期刊: Kidney Int (In press)
• 作者: Nishitani Y;Iwano M et al.
• 通讯作者: Iwano M et al.

線維芽細胞を中心とした間質線維化の発症機構について

以成纤维细胞为中心的间质纤维化的发生机制

• 发表时间: 2004
• 期刊: 関西実験動物研究会会報 25
• 作者: Yamazato M;Ohya Y;Nakamoto M;et al.;岩野正之
• 通讯作者: 岩野正之

Iwano M, Neilson EG: "Mechanisms of tubulointerstitial fibrosis"Current Opinion in Nephrology and Hypertension. in press.

Iwano M，Neilson EG：“肾小管间质纤维化的机制”肾脏病学和高血压的当前观点。

組織の線維化と筋線維芽細胞:起源とその運命

组织纤维化和肌成纤维细胞：起源和命运

• 发表时间: 2004
• 期刊: 炎症と免疫 12(6)
• 作者: Sato Y;Shomura H;Maeda Y;Mine T;Une Y;Akasaka Y;Kondo M;Takahashi S;Shinohara T;Katagiri K;Sato M;Okada S;Matsui K;Yamada A;Yamana H;Itoh K;Todo S.;Imanishi K;岩野正之
• 通讯作者: 岩野正之

MECHANISMS OF TUBULOINTERSTITIAL FIBROSIS

• DOI: 10.1038/ki.1991.63
• 发表时间: 1991-03-01
• 期刊: KIDNEY INTERNATIONAL
• 影响因子: 19.6
• 作者: KUNCIO, GS;NEILSON, EG;HAVERTY, T
• 通讯作者: HAVERTY, T