Department of Orthopedics, Zhong Da Hospital, School of Medicine, Southeast University, 210009 Nanjing, Jiangsu, China.
Research Center for Bone and Stem Cells; Key Laboratory for Aging & Disease; Nanjing Medical University, 211166 Nanjing, Jiangsu, China.
Front Biosci (Landmark Ed). 2024 Mar 20;29(3):115. doi: 10.31083/j.fbl2903115.
Postmenopausal osteoporosis (PMOP) is a prevalent disease, which features decreased bone mass, bone weakness and deteriorated bone microstructure in postmenopausal women. Although many factors have been revealed to contribute to the occurrence of PMOP, its mechanism remains undefined. This work aimed to identify significant changes in gene expression during PMOP formation and to examine the most valuable differential genes in postmenopausal osteoporosis versus the control group.
The GSE68303 dataset that contains 12 ovariectomize (OVX) experimental and 11 sham groups was downloaded and analyzed. The results indicated that interferon regulatory factor 4 () might be a hub gene in the development of postmenopausal osteoporosis. Western blot and immunohistochemistry were carried out to evaluate IRF4 levels in thoracic vertebra extracts from OVX and Sham mice. To assess IRF4's impact on osteogenic differentiation in postmenopausal bone marrow mesenchymal stem cells (BM-MSCs), IRF4 overexpression (OV-IRF4) and knockdown (Sh-IRF4) plasmids were constructed.
The results showed that comparing with the sham group, bone samples from the OVX group showed higher IRF4 expression. Alkaline phosphatase (ALP) staining revealed that IRF4 overexpression significantly inhibited ALP activity, while IRF4 knockdown promoted ALP activity in BM-MSCs. Simvastatin-treated OVX mice showed increased total bone volume/total tissue volume (BV/TV) and elevated Runx2 expression by immunohistochemical staining compared with the OVX group.
This study demonstrated that IRF4 is associated with OVX induced osteoporosis, it can regulate bone stability by inhibiting the osteogenic differentiation BM-MSCs. This study may help enhance our understanding of the molecular mechanism of PMOP formation, providing new insights into estrogen defiance induced osteoporosis.
绝经后骨质疏松症（PMOP）是一种常见疾病，其特征在于绝经后妇女的骨量减少、骨强度降低和骨微观结构恶化。虽然已经发现许多因素与 PMOP 的发生有关，但其机制仍不清楚。本研究旨在鉴定 PMOP 形成过程中基因表达的显著变化，并研究绝经后骨质疏松症与对照组之间最有价值的差异基因。
下载并分析了包含 12 个去卵巢（OVX）实验组和 11 个假手术组的 GSE68303 数据集。结果表明，干扰素调节因子 4（IRF4）可能是绝经后骨质疏松症发展的一个枢纽基因。通过 Western blot 和免疫组织化学检测 OVX 和 Sham 小鼠胸腰椎提取物中的 IRF4 水平。为了评估 IRF4 对绝经后骨髓间充质干细胞（BM-MSCs）成骨分化的影响，构建了 IRF4 过表达（OV-IRF4）和敲低（Sh-IRF4）质粒。
结果显示，与假手术组相比，OVX 组骨样本中 IRF4 表达升高。碱性磷酸酶（ALP）染色显示，IRF4 过表达显著抑制了 BM-MSCs 中的 ALP 活性，而 IRF4 敲低则促进了 ALP 活性。与 OVX 组相比，辛伐他汀处理的 OVX 小鼠的总骨体积/总组织体积（BV/TV）增加，Runx2 表达通过免疫组织化学染色升高。
本研究表明，IRF4 与 OVX 诱导的骨质疏松症有关，它可以通过抑制 BM-MSCs 的成骨分化来调节骨稳定性。本研究可能有助于增强我们对 PMOP 形成分子机制的理解，为雌激素抵抗诱导的骨质疏松症提供新的见解。
