Hrd1 and ER-Associated Protein Degradation, ERAD, are Critical Elements of the Adaptive ER Stress Response in Cardiac Myocytes.
Hrd1 and ER-Associated Protein Degradation, ERAD, are Critical Elements of the Adaptive ER Stress Response in Cardiac Myocytes.
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DOI：
10.1161/circresaha.115.306993
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发表时间：
2015-08-28
影响因子：
20.1
通讯作者：
Glembotski CC
中科院分区：
文献类型：
--
作者：
Doroudgar S;Völkers M;Thuerauf DJ;Khan M;Mohsin S;Respress JL;Wang W;Gude N;Müller OJ;Wehrens XH;Sussman MA;Glembotski CC
Hrd1是一种内质网(ER)-跨膜E3泛素连接酶，已在酵母中进行了研究，它通过ER相关降解(ERAD)在ER应激过程中积累的错误折叠蛋白来参与ER蛋白质质量控制。Hrd1和ERAD都没有在心脏或心肌细胞中进行研究，在心肌细胞中，蛋白质质量控制对正常的心脏功能至关重要。本研究的目的是阐明Hrd1在内质网应激、ERAD和活体培养的心肌细胞和小鼠心脏中的作用。在培养的新生大鼠心肌细胞上检测了siRNA介导的Hrd1基因敲除的作用。研究了腺相关病毒(AAV)介导的Hrd1基因敲除和过表达对压力超负荷致小鼠病理性心肌肥厚的影响。在心肌细胞中，内质网应激源thapsigargin(TG)和衣霉素(TM)增加ERAD，以及适应性内质网应激蛋白，并且对细胞死亡的影响最小。然而，当Hrd1被敲除时，TG和TM显著降低ERAD，同时增加不适应内质网应激蛋白和细胞死亡。在体内，Hrd1基因敲除可加重压力超负荷小鼠心脏功能障碍，增加心肌细胞凋亡和心肌肥厚，而过表达Hrd1基因可保护心功能，减少细胞凋亡，减轻心肌肥厚。Hrd1和ERAD是心肌细胞适应性内质网应激反应的重要组成部分。在病理性心肌肥厚的小鼠模型中，Hrd1有助于保护心脏的结构和功能。
Hrd1 is an endoplasmic reticulum (ER)-transmembrane E3 ubiquitin ligase that has been studied in yeast, where it contributes to ER protein quality control by ER-associated degradation (ERAD) of misfolded proteins that accumulate during ER stress. Neither Hrd1 nor ERAD have been studied in the heart, or in cardiac myocytes, where protein quality control is critical for proper heart function. The objectives of this study were to elucidate roles for Hrd1 in ER stress, ERAD, and viability in cultured cardiac myocytes and in the mouse heart, in vivo. The effects of siRNA-mediated Hrd1 knockdown were examined in cultured neonatal rat ventricular myocytes. The effects of adeno-associated virus (AAV)-mediated Hrd1 knockdown and overexpression were examined in the hearts of mice subjected to pressure-overload induced pathological cardiac hypertrophy, which challenges protein-folding capacity. In cardiac myocytes, the ER stressors, thapsigargin (TG) and tunicamycin (TM) increased ERAD, as well as adaptive ER stress proteins, and minimally affected cell death. However, when Hrd1 was knocked down, TG and TM dramatically decreased ERAD, while increasing maladaptive ER stress proteins and cell death. In vivo, Hrd1 knockdown exacerbated cardiac dysfunction, and increased apoptosis and cardiac hypertrophy, while Hrd1 overexpression preserved cardiac function, and decreased apoptosis and attenuated cardiac hypertrophy in the hearts of mice subjected to pressure-overload. Hrd1 and ERAD are essential components of the adaptive ER stress response in cardiac myocytes. Hrd1 contributes to preserving heart structure and function in a mouse model of pathological cardiac hypertrophy.