Hrd1 participates in the regulation of collagen I synthesis in renal fibrosis
Hrd1 participates in the regulation of collagen I synthesis in renal fibrosis
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Hrd1参与肾纤维化中I型胶原合成的调节
DOI：
10.1007/s11010-013-1843-z
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发表时间：
2014-01-01
影响因子：
4.3
通讯作者：
Liang, Xiubin
中科院分区：
文献类型：
--
作者：
Li, Lei;Shen, Yachen;Liang, Xiubin
富胶原细胞外基质的产生和积累是肾纤维化过程中的共同特征。然而，肾纤维化中胶原合成的调控机制尚不清楚。Hrd1是E3泛素连接酶，在内质网蛋白折叠和转运到高尔基体中起重要作用。在这里，我们检验了Hrd1翻译后调节肾间质纤维化中胶原合成的假设。单侧输尿管梗阻诱导Hrd1表达，主要表达于纤维化肾间质和肾小管上皮。转化生长因子β1作为肾纤维化的关键介质，在肾小管上皮细胞中Hrd1、α-平滑肌肌动蛋白、纤维连接蛋白以及I型前胶原和成熟胶原的表达呈剂量依赖性增加，提示I型胶原成熟可能在肾纤维化过程中受到调节。在培养的肾成纤维细胞中，Hrd1敲低可使NRK-49F细胞上清液中分泌的I型胶原减少60%。相反，Hrd1过表达可使分泌的I型胶原增加1.5倍。Hrd1过表达显著增加了I型前胶原和I型成熟胶原的表达，分别增加了~2.2倍和~1.8倍。然而，Hrd1的下调使成熟I型胶原的表达显著降低~ 80%，而前I型胶原的表达仅降低~ 21%。此外，短干扰rna诱导的Sec23A敲低抑制了Hrd1过表达导致的I型胶原（未成熟型和成熟型）表达的增加，并使I型胶原表达恢复到控制水平。这些结果表明，Hrd1在肾纤维化中I型胶原的成熟中起重要作用，而Sec23A通路是ER-to-Golgi前胶原转运促进胶原合成所必需的。
The production and accumulation of collagen-rich extracellular matrix are common hallmarks during the process of renal fibrogenesis. However, the mechanisms of the regulation of collagen synthesis in renal fibrosis are still unclear. Hrd1, an E3 ubiquitin ligase, plays important roles for protein folding in ER and transport to Golgi. Here, we examined the hypothesis that Hrd1 posttranslationally regulates collagen synthesis in renal interstitial fibrogenesis. Unilateral ureteral obstruction induced Hrd1 expression, predominantly in the renal interstitium and tubular epithelium of fibrotic kidneys. Transforming growth factor β1, as a key mediator in kidney fibrosis, significantly increased the expressions of Hrd1, α-smooth muscle actin, fibronectin as well as procollagen I and mature collagen I in dose-dependent manner in tubular epithelial cells, suggesting that collagen I maturation might be modulated during renal fibrosis. In cultured renal fibroblasts, Hrd1 knockdown decreased secreted collagen I ~60 % in the supernatant of NRK-49F cells. Conversely, Hrd1 overexpression increased secreted collagen I ~1.5-fold. Hrd1 overexpression significantly increased the expressions of both procollagen I and mature collagen I, ~2.2-fold and ~1.8-fold, respectively. However, Hrd1 knockdown markedly decreased the expression of mature collagen I ~80 %, while procollagen I expression only was decreased ~21 %. Moreover, short interfering RNA-induced knockdown of Sec23A blunted the increase in collagen I expression (both immature and mature form) by Hrd1 overexpression and returned collagen I expression toward control levels. These results indicate that Hrd1 plays an important role in the maturation of collagen I in renal fibrosis, and that Sec23A pathway is required for ER-to-Golgi procollagen trafficking to promote collagen synthesis.