He Juan, Cao Yanan, Su Tingwei, Jiang Yiran, Jiang Lei, Zhou Weiwei, Zhang Cui, Wang Weiqing, Ning Guang
Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai Key Laboratory for Endocrine Tumors, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Laboratory of Endocrinology and Metabolism, Institute of Health Sciences, Shanghai Institutes for Biological Science (SIBS), Chinese Academy of Science (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), Shanghai, China.
Clin Endocrinol (Oxf). 2015 Oct;83(4):581-9. doi: 10.1111/cen.12814. Epub 2015 Jun 11.
Previous studies have investigated the genetic and molecular basis of primary aldosteronism (PA), a common cause of human hypertension, but the effects of microRNAs (miRNAs) on the adrenocortical cell proliferation and aldosterone production are largely obscure. Here, we characterized miRNA expression patterns in the subtypes of PA to gain a better understanding of its pathogenesis.
miRNA expression was assessed by microarray profiling analysis in aldosterone-producing adenoma (APA), unilateral adrenal hyperplasia (UAH) and normal adrenal cortex tissues. Selected differentially expressed miRNAs were further validated in a validation cohort by qRT-PCR. A gain-of-function approach was used to explore the functional role of the specific miRNA in vitro.
Of 31 miRNAs including miR-375, miR-7 and miR-29b were found to be significantly differentially expressed among these three groups. miR-375 was the most downregulated one in adrenal cortex tissues from PA patients, and its expression level was inversely correlated with the tumour size in APA. Overexpression of miR-375 in a human adrenocortical cell line (H295R) reduced cell proliferation and suppressed the expression of MTDH (metadherin, also known as astrocyte elevated gene-1). Moreover, MTDH was verified as a direct target of miR-375 through luciferase reporter assays. Knock-down of MTDH in H295R cells attenuated Akt-Ser473 phosphorylation and inhibited cell viability.
Our findings suggest that miR-375 exerts its tumour-suppressive function via targeting MTDH/Akt pathway and implicate a potential therapeutic target in PA.
既往研究已对原发性醛固酮增多症（PA）这一人类高血压常见病因的遗传和分子基础进行了探究，但微小RNA（miRNA）对肾上腺皮质细胞增殖及醛固酮生成的影响在很大程度上仍不清楚。在此，我们对PA各亚型中的miRNA表达模式进行了特征分析，以更好地了解其发病机制。
通过微阵列分析评估醛固酮瘤（APA）、单侧肾上腺增生（UAH）及正常肾上腺皮质组织中的miRNA表达情况。通过qRT-PCR在验证队列中进一步验证选定的差异表达miRNA。采用功能获得性方法在体外探究特定miRNA的功能作用。
在这31种miRNA中，发现miR-375、miR-7和miR-29b在这三组中存在显著差异表达。miR-375是PA患者肾上腺皮质组织中下调最明显的一种，其表达水平与APA中的肿瘤大小呈负相关。在人肾上腺皮质细胞系（H295R）中过表达miR-375可减少细胞增殖并抑制MTDH（黏附素，也称为星形胶质细胞上调基因-1）的表达。此外，通过荧光素酶报告基因实验证实MTDH是miR-375的直接靶点。在H295R细胞中敲低MTDH可减弱Akt-Ser473磷酸化并抑制细胞活力。
我们的研究结果表明，miR-375通过靶向MTDH/Akt途径发挥其肿瘤抑制功能，并提示PA中有一个潜在的治疗靶点。
