CASZ1b is a novel transcriptional corepressor of mineralocorticoid receptor
CASZ1b is a novel transcriptional corepressor of mineralocorticoid receptor
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DOI：
10.1038/s41440-020-00562-5
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发表时间：
2020-10
影响因子：
5.4
通讯作者：
K. Yokota;H. Shibata;I. Kurihara;Sakiko Kobayashi;Ayano Murai-Takeda;H. Itoh
中科院分区：
文献类型：
--
作者：
K. Yokota;H. Shibata;I. Kurihara;Sakiko Kobayashi;Ayano Murai-Takeda;H. Itoh
醛固酮是盐皮质激素受体（MR）的生物配体，其通过促进肾脏中的钠重吸收来升高血压。然而，醛固酮-MR介导的转录的分子机制和这种转录在高血压中的作用仍然在很大程度上未知。在这项研究中，我们的目的是确定新的MR协同调节剂和阐明高血压的分子机制之一。我们通过生化方法从稳定表达FLAG-MR的HEK 293 F细胞中纯化MR相互作用因子，并通过液相色谱-串联质谱分析鉴定了蓖麻锌指蛋白同源物1亚型B（CASZ 1 B）作为候选的新型MR协同调节因子。在全基因组单核苷酸多态性研究中，CASZ 1基因与高血压有关，但其在高血压发展中的作用仍不清楚。我们发现CASZ 1b与MR在肾脏中共定位，并以醛固酮依赖性方式与MR相互作用。在使用HEK 293 F细胞的荧光素酶测定中，CASZ 1b的过表达使醛固酮依赖性MR转录活性降低约50%。相比之下，通过RNA干扰敲低CASZ 1b使醛固酮诱导的MR靶基因上皮Na+通道-α（ENaCα）和血清/糖皮质激素调节激酶1（SGK 1）的表达水平分别增加约2倍和2.3倍。在醛固酮-MR结合后，CASZ 1b与MR相互作用并与核小体重塑脱乙酰酶（Mi-2/NuRD）形成蛋白复合物，该蛋白复合物具有染色质重塑和组蛋白脱乙酰化活性的辅阻遏物复合物，其抑制ENaCα和SGK 1。这些发现揭示了CASZ 1b在调节MR介导的转录活性方面的关键作用，并为高血压的病理生理学提供了新的见解。
Aldosterone is a biological ligand for mineralocorticoid receptor (MR) that elevates blood pressure by promoting sodium reabsorption in the kidneys. However, the molecular mechanisms of aldosterone-MR-mediated transcription and the role of this transcription in hypertension remain largely unknown. In this study, we aimed to identify novel MR coregulators and elucidate one of the molecular mechanisms of hypertension. We purified MR-interacting factors from HEK293F cells stably expressing FLAG-MR through a biochemical approach and identified the zinc finger protein castor homolog 1 isoform b (CASZ1b) as a candidate novel MR coregulator via liquid chromatography—tandem mass spectrometry analysis. The CASZ1 gene has been implicated in hypertension in genome-wide single-nucleotide polymorphism studies, but its role in the development of hypertension remains unclear. We found that CASZ1b colocalized with MR in the kidneys and interacted with MR in an aldosterone-dependent manner. In luciferase assays using HEK293F cells, overexpression of CASZ1b reduced aldosterone-dependent MR transcriptional activity by ~50%. In contrast, knockdown of CASZ1b via RNA interference increased the expression levels of the aldosterone-induced MR target genes epithelial Na+channel-α (ENaCα) and serum/glucocorticoid regulated kinase 1 (SGK1) by approximately twofold and 2.3-fold, respectively. Upon aldosterone-MR binding, CASZ1b interacted with MR and formed a protein complex with nucleosome remodeling deacetylase (Mi-2/NuRD), a corepressor complex with chromatin remodeling and histone deacetylation activity, which suppressed ENaCα and SGK1. These findings reveal a critical role of CASZ1b in regulating MR-mediated transcriptional activity and provide new insights into the pathophysiology of hypertension.