INTRODUCTION Postmenopausal osteoporosis (PMOP) is mainly caused by multiple factors. Recent studies have suggested that iron accumulation was closely related to PMOP. However, the detailed molecular mechanisms have not been well demonstrated. Experimental Procedures We constructed the iron accumulation (IA) mouse model by intraperitoneal injections of ferric ammonium citrate (FAC) and cell model by culturing with the medium containing FAC. Osteoporosis was confirmed in mouse bone tissues using H&E staining and the level of serum ferritin, alkaline phosphatase (ALP), procollagen-1 N-terminal peptide (P1NP), and osteocalcin in mice were examined by ELISA. The expressions of XIST and miR-758-3p were deteced by qRT-PCR. Cell proliferation and apoptosis were measured by CCK-8, TUNEL, and flow cytometry. The expression levels of apoptotic-related proteins were evaluated by western blot. Dual luciferase reporter assay was used to examine the molecular interaction. The expressions of ALP, P1NP, and osteocalcin, and the H&E staining of bone tissues in mice were analyzed to comfirm the biological function of XIST and miR-758-3p in vivo. RESULTS XIST was up-regulated while miR-758-3p was down-regulated in IA mouse and cells models. XIST knockdown significantly reduced FAC-induced osteoblast apoptosis, which was mimicked by transfection with miR-758-3p mimics. XIST acted as a sponge of miR-758-3p, which targeted caspase 3. Iron accumulation led to the high expression of XIST and promoted osteoblast apoptosis through miR-758-3p/caspase 3. Transfection with shXIST or miR-758-3p mimics alleviated IA-induced mouse osteoporosis. CONCLUSION Iron accumulation regulated osteoblast apoptosis through XIST/miR-758-3p/caspase 3 axis, which might provide alternative targets for the treatment of osteoporosis. This article is protected by copyright. All rights reserved.

中文翻译：

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铁积累通过 lncRNA XIST / miR-758-3p/caspase 3 轴调节成骨细胞凋亡，导致骨质疏松

引言 绝经后骨质疏松症（PMOP）主要由多种因素引起。最近的研究表明，铁的积累与 PMOP 密切相关。然而，详细的分子机制尚未得到很好的证明。实验步骤我们通过腹腔注射柠檬酸铁铵(FAC)构建了铁积累(IA)小鼠模型，并通过用含有FAC的培养基培养构建了细胞模型。使用 H&E 染色在小鼠骨组织中确认骨质疏松症，并通过 ELISA 检测小鼠中血清铁蛋白、碱性磷酸酶 (ALP)、前胶原-1 N-末端肽 (P1NP) 和骨钙素的水平。qRT-PCR检测XIST和miR-758-3p的表达。通过CCK-8、TUNEL和流式细胞术测量细胞增殖和凋亡。通过蛋白质印迹评估凋亡相关蛋白的表达水平。双荧光素酶报告基因测定用于检查分子相互作用。分析小鼠ALP、P1NP、骨钙素的表达及骨组织的H&E染色，证实XIST和miR-758-3p在体内的生物学功能。结果 XIST 在 IA 小鼠和细胞模型中上调，而 miR-758-3p 下调。XIST 敲低显着降低了 FAC 诱导的成骨细胞凋亡，这是通过转染 miR-758-3p 模拟物来模拟的。XIST 充当 miR-758-3p 的海绵，靶向 caspase 3。铁积累导致 XIST 的高表达并通过 miR-758-3p/caspase 3 促进成骨细胞凋亡。用 shXIST 或 miR-758-3p 模拟物转染减轻IA诱导的小鼠骨质疏松症。结论 铁积累通过XIST/miR-758-3p/caspase 3轴调节成骨细胞凋亡，这可能为骨质疏松症的治疗提供替代靶点。本文受版权保护。版权所有。