Traditionally, hyperthyroid-associated osteoporosis has been considered to be the result of increased thyroid hormone levels. The pathogenesis of hyperthyroid-associated osteoporosis remains unclear. Thyroid stimulating hormone receptor (TSHR) is closely associated with osteoporosis. Our study aimed to explore the role of TSHR and its upstream microRNA (miRNA) in hyperthyroid-associated osteoporosis. Bioinformatics analysis (starBase and Targetscan) and a wide range of experiments including reverse-transcription quantitative polymerase chain reaction, luciferase reporter, western blot analysis of osteogenic differentiation markers including OSX, OCN, ALP, OPN, and COL1, hematoxylin and eosin staining, Alizarin Red staining assays were used to explore the function and mechanism of TSHR in hyperthyroid-associated osteoporosis. First, we observed that TSHR was downregulated in bone marrow mesenchymal stem cells (BMSCs) isolated from rats after culture in osteogenic medium for 7 days. Functionally, overexpression of TSHR accelerates BMSC osteogenic differentiation. Mechanistically, we predicted four potential miRNAs for TSHR. MiR-577 was validated to bind with TSHR. Rescue assays showed that miR-577 overexpression inhibited BMSC osteogenic differentiation via targeting TSHR. In vivo experiments showed that miR-577 aggravated bone loss and bone remodeling and our data showed that it is achieved by targeting TSHR in hyperthyroid-associated osteoporosis. This finding may deep our understanding of the pathogenesis of hyperthyroid-associated osteoporosis.

中文翻译：

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MicroRNA-577通过靶向促甲状腺激素受体在甲亢相关骨质疏松症中加重骨质流失和骨重塑

传统上，甲亢相关的骨质疏松症被认为是甲状腺激素水平升高的结果。甲亢相关骨质疏松症的发病机制尚不清楚。促甲状腺激素受体（TSHR）与骨质疏松症密切相关。我们的研究旨在探讨 TSHR 及其上游 microRNA (miRNA) 在甲亢相关骨质疏松症中的作用。生物信息学分析（starBase 和 Targetscan）和广泛的实验，包括逆转录定量聚合酶链反应、荧光素酶报告基因、成骨分化标志物（包括 OSX、OCN、ALP、OPN 和 COL1）的蛋白质印迹分析、苏木精和伊红染色、茜素采用红染色法探讨TSHR在甲亢相关骨质疏松症中的作用及机制。第一的，我们观察到在成骨培养基中培养 7 天后，从大鼠分离的骨髓间充质干细胞 (BMSCs) 中 TSHR 下调。在功能上，TSHR 的过表达加速了 BMSC 成骨分化。从机制上讲，我们预测了 TSHR 的四种潜在 miRNA。MiR-577 经验证可与 TSHR 结合。救援分析表明，miR-577 过表达通过靶向 TSHR 抑制 BMSC 成骨分化。体内实验表明，miR-577 会加重骨丢失和骨重塑，我们的数据表明，它是通过在甲状腺功能亢进相关的骨质疏松症中靶向 TSHR 来实现的。这一发现可能加深我们对甲亢相关骨质疏松症发病机制的认识。