A new role for HERPUD1 and ERAD activation in osteoblast differentiation and mineralization
A new role for HERPUD1 and ERAD activation in osteoblast differentiation and mineralization
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DOI：
10.1096/fj.201701229rr
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发表时间：
2018-09-01
期刊：
影响因子：
4.8
通讯作者：
Quiroga, Clara
中科院分区：
文献类型：
--
作者：
Americo-Da-Silva, Luan;Diaz, Jheimmy;Quiroga, Clara
骨完整性依赖于成骨细胞合成骨和破骨细胞吸收骨之间的精细平衡。成熟成骨细胞的分泌能力需要严格的蛋白酶抑制控制。内质网相关降解（ERAD）通过位错进入细胞质和蛋白酶体降解阻止未折叠内质网蛋白的积累。ER膜蛋白是具有泛素样结构域1的同型半胱氨酸诱导内质网蛋白（HERPUD1），是ERAD多蛋白复合物的关键组成部分，有助于稳定复合物并促进未折叠蛋白的有效降解。未折叠蛋白反应和细胞应激强烈上调HERPUD1的表达。本研究的目的是确定HERPUD1和ERAD是否在成骨细胞分化和成熟中发挥作用。我们通过测量钙沉积水平、碱性磷酸酶活性、矮子相关转录因子2和成骨细胞表达来评估成骨前MC3T3-E1细胞和原代大鼠成骨细胞的分化。我们发现ERAD和蛋白酶体降解被激活，HERPUD1的表达随着成骨细胞分化的进展而增加。HERPUD1缺失阻断体外成骨细胞矿化，并显著降低碱性磷酸酶活性。相反，HERPUD1过表达激活成骨细胞分化程序。我们的研究结果表明HERPUD1和ERAD对成骨细胞成熟程序的激活很重要，可能是阐明骨生理学的有用新靶点。Americo-Da-Silva， L., Diaz， J., Bustamante， M., Mancilla， G., Oyarzun， I., Verdejo, h.e, Quiroga， C. HERPUD1和ERAD激活在成骨细胞分化和矿化中的新作用。
Bone integrity depends on a finely tuned balance between bone synthesis by osteoblasts and resorption by osteoclasts. The secretion capacity of mature osteoblasts requires strict control of proteostasis. Endoplasmic reticulum-associated degradation (ERAD) prevents the accumulation of unfolded ER proteins via dislocation to the cytosol and degradation by the proteasome. The ER membrane protein, homocysteine-inducible endoplasmic reticulum protein with ubiquitin-like domain 1 (HERPUD1), is a key component of the ERAD multiprotein complex which helps to stabilize the complex and facilitate the efficient degradation of unfolded proteins. HERPUD1 expression is strongly up-regulated by the unfolded protein response and cellular stress. The aim of the current study was to establish whether HERPUD1 and ERAD play roles in osteoblast differentiation and maturation. We evaluated preosteoblastic MC3T3-E1 cell and primary rat osteoblast differentiation by measuring calcium deposit levels, alkaline phosphatase activity, and runt-related transcription factor 2 and osterix expression. We found that ERAD and proteasomal degradation were activated and that HERPUD1 expression was increased as osteoblast differentiation progressed. The absence of HERPUD1 blocked osteoblast mineralization in vitro and significantly reduced alkaline phosphatase activity. In contrast, HERPUD1 overexpression activated the osteoblast differentiation program. Our results demonstrate that HERPUD1 and ERAD are important for the activation of the osteoblast maturation program and may be useful new targets for elucidating bone physiology.Americo-Da-Silva, L., Diaz, J., Bustamante, M., Mancilla, G., Oyarzun, I., Verdejo, H. E., Quiroga, C. A new role for HERPUD1 and ERAD activation in osteoblast differentiation and mineralization.