Cartilage intermediate layer protein-1 alleviates pressure overload-induced cardiac fibrosis via interfering TGF-β1 signaling
Cartilage intermediate layer protein-1 alleviates pressure overload-induced cardiac fibrosis via interfering TGF-β1 signaling
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DOI：
10.1016/j.yjmcc.2018.02.006
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发表时间：
2018-03-01
影响因子：
5
通讯作者：
Li, Li
中科院分区：
文献类型：
--
作者：
Zhang, Cheng-Lin;Zhao, Qian;Li, Li
心脏纤维化的特征是心肌中细胞外基质（ECM）蛋白过度沉积，导致心室顺应性降低和舒张功能障碍。软骨中间层蛋白-1 (CILP-1) 是一种新发现的心脏基质细胞蛋白，在大多数与心脏重塑相关的情况下表达上调，然而，CILP-1 是否参与压力超负荷诱导的纤维化反应尚不清楚。在这里，我们研究了 CILP-1 是否关键参与压力超负荷引起的纤维化重塑。 Western blot 分析和免疫荧光染色表明 CILP-1 主要在心肌细胞中检测到，在间质中检测到的程度较小。在分离的成年小鼠心室肌细胞和非肌细胞中，发现 CILP-1 主要由肌细胞合成。在经历横主动脉缩窄 (TAC) 的 C57BL/6 小鼠中，左心室中的 CILP-1 表达上调。通过超声心动图测试、形态学检查和纤维化分子的基因表达测量，心肌 CILP-1 敲低加剧，而 CILP-1 过表达减弱 TAC 诱导的心室重塑和功能障碍。将心脏成纤维细胞与含有全长、N 末端或 C 末端 CILP-1 的条件培养基一起孵育，可抑制转化生长因子 (TGF)-β 1 诱导的 Smad3 磷酸化和随后的促纤维化事件。我们首先证明C端CILP-1增加Akt磷酸化，促进Akt和Smad3之间的相互作用，并抑制Smad3磷酸化。 PI3K-Akt 通路的阻断减弱了 C-CILP-1 对 TGF-β1 诱导的 Smad3 激活的抑制作用。我们得出结论，CILP-1是一种新型ECM蛋白，在压力过载诱导的纤维化重塑中具有抗纤维化能力。 CILP-1 的这种抗纤维化作用归因于通过其 N 端和 C 端片段干扰 TGF-β 1 信号传导。
Cardiac fibrosis is characterized by excessive deposition of extracellular matrix (ECM) proteins in the myocardium and results in decreased ventricular compliance and diastolic dysfunction. Cartilage intermediate layer protein-1 (CILP-1), a novel identified cardiac matricellular protein, is upregulated in most conditions associated with cardiac remodeling, however, whether CILP-1 is involved in pressure overload-induced fibrotic response is unknown. Here, we investigated whether CILP-1 was critically involved in the fibrotic remodeling induced by pressure overload. Western blot analysis and immunofluorescence staining showed that CILP-1 was predominantly detected in cardiac myocytes and to a less extent in the interstitium. In isolated adult mouse ventricular myocytes and nonmyocytes, CILP-1 was found to be mainly synthesized by myocytes. CILP-1 expression in left ventricles was upregulated in C57BL/6 mice undergoing transverse aortic constriction (TAC). Myocardial CILP-1 knockdown aggravated whereas CILP-1 overexpression attenuated TAC-induced ventricular remodeling and dysfunction, as measured by echocardiography test, morphological examination, and gene expressions of fibrotic molecules. Incubation of cardiac fibroblasts with the conditioned medium containing full-length, N terminal, or C-terminal CILP-1 inhibited transforming growth factor (TGF)-beta 1-induced Smad3 phosphorylation and the subsequent profibrotic events. We first demonstrated that C-terminal CILP-1 increased Akt phosphorylation, promoted the interaction between Akt and Smad3, and suppressed Smad3 phosphorylation. Blockade of PI3K-Akt pathway attenuated the inhibitory effect of C-CILP-1 on TGF-beta 1-induced Smad3 activation. We conclude that CILP-1 is a novel ECM protein possessing anti-fibrotic ability in pressure overload-induced fibrotic remodeling. This anti-fibrotic effect of CILP-1 attributes to interfering TGF-beta 1 signaling through its N- and C terminal fragments.