Abstract：
BACKGROUND: Epithelial stromal interaction 1 (EPSTI1) plays an important role in M1 macrophages, which induce osteoclastogenesis. One recent genome-wide association study (GWAS) involving 426,824 individuals has shown that EPSTI1 is strongly associated with osteoporosis (P < 5E-8). Therefore, we speculate that EPSTI1 participates in the modulation of osteoporosis through osteoclastogenesis. The roles of EPSTI1 in osteoclastogenesis and bone resorption remain unclear.
METHODS: Femur specimens were collected from osteoporotic patients and control patients. Immunofluorescence staining was used to detect the expression of EPSTI1 and signaling pathways. The osteoclastic potential of RAW264.7 cells with Sh-EPSTI1 lentivirus infection was tested using tartrate-resistant acid phosphatase (TRAP) staining, western blotting, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Western blotting was also used to examine signaling pathways.
RESULTS: In this study, EPSTI1 was found to be significantly increased in tartrate-resistant acid phosphatase positive (ACP5+) osteoclasts of bone sections from osteoporotic patients. Next, we identified EPSTI1 as a positive regulator of osteoclastogenesis and osteoclast differentiation capability. Diminished EPSTI1 expression resulted in reduced osteoclastic resorption. Mechanistically, EPSTI1-driven osteoclastogenesis was regulated by NF-κB pathway, which was mediated by the phosphorylation of protein kinase R (p-PKR). Furthermore, EPSTI1 participating in the modulation of osteoporosis via PKR/NF-κB pathway was also verified in the bone samples of osteoporotic patients.
CONCLUSIONS: Collectively, our findings suggest that EPSTI1 may regulate osteoclast differentiation and bone resorption through PKR/NF-κB pathway and in vivo experiments are needed to further verify EPSTI1 as the therapy target for osteoporosis.
METHODS: Femur specimens were collected from osteoporotic patients and control patients. Immunofluorescence staining was used to detect the expression of EPSTI1 and signaling pathways. The osteoclastic potential of RAW264.7 cells with Sh-EPSTI1 lentivirus infection was tested using tartrate-resistant acid phosphatase (TRAP) staining, western blotting, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Western blotting was also used to examine signaling pathways.
RESULTS: In this study, EPSTI1 was found to be significantly increased in tartrate-resistant acid phosphatase positive (ACP5+) osteoclasts of bone sections from osteoporotic patients. Next, we identified EPSTI1 as a positive regulator of osteoclastogenesis and osteoclast differentiation capability. Diminished EPSTI1 expression resulted in reduced osteoclastic resorption. Mechanistically, EPSTI1-driven osteoclastogenesis was regulated by NF-κB pathway, which was mediated by the phosphorylation of protein kinase R (p-PKR). Furthermore, EPSTI1 participating in the modulation of osteoporosis via PKR/NF-κB pathway was also verified in the bone samples of osteoporotic patients.
CONCLUSIONS: Collectively, our findings suggest that EPSTI1 may regulate osteoclast differentiation and bone resorption through PKR/NF-κB pathway and in vivo experiments are needed to further verify EPSTI1 as the therapy target for osteoporosis.
摘要：
背景：上皮基质相互作用1（EPSTI1）在M1巨噬细胞中起重要作用，诱导破骨细胞生成。最近一项涉及426,824名个体的全基因组关联研究（GWAS）表明，EPSTI1与骨质疏松症密切相关（P<5E-8）。因此,我们推测EPSTI1通过破骨细胞的形成参与了骨质疏松的调节。EPSTI1在破骨细胞生成和骨吸收中的作用尚不清楚。
方法：收集骨质疏松患者和对照组患者的股骨标本。免疫荧光染色用于检测EPSTI1和信号通路的表达。使用抗酒石酸酸性磷酸酶（TRAP）染色测试了Sh-EPSTI1慢病毒感染的RAW264.7细胞的破骨细胞潜能，西方印迹,和定量逆转录聚合酶链反应(qRT-PCR)。蛋白质印迹也用于检查信号传导途径。
结果：在这项研究中，发现EPSTI1在骨质疏松患者骨切片的抗酒石酸酸性磷酸酶阳性（ACP5）破骨细胞中显着增加。接下来,我们确定EPSTI1是破骨细胞生成和破骨细胞分化能力的正调节因子。EPSTI1表达减少导致破骨细胞吸收减少。机械上,EPSTI1驱动的破骨细胞生成受NF-κB通路调控,它是由蛋白激酶R(p-PKR)的磷酸化介导的。此外，EPSTI1通过PKR/NF-κB途径参与骨质疏松的调节也在骨质疏松患者的骨样本中得到证实。
结论：总的来说，我们的研究结果表明,EPSTI1可能通过PKR/NF-κB通路调节破骨细胞分化和骨吸收,需要体内实验进一步验证EPSTI1作为骨质疏松症的治疗靶点.
方法：收集骨质疏松患者和对照组患者的股骨标本。免疫荧光染色用于检测EPSTI1和信号通路的表达。使用抗酒石酸酸性磷酸酶（TRAP）染色测试了Sh-EPSTI1慢病毒感染的RAW264.7细胞的破骨细胞潜能，西方印迹,和定量逆转录聚合酶链反应(qRT-PCR)。蛋白质印迹也用于检查信号传导途径。
结果：在这项研究中，发现EPSTI1在骨质疏松患者骨切片的抗酒石酸酸性磷酸酶阳性（ACP5）破骨细胞中显着增加。接下来,我们确定EPSTI1是破骨细胞生成和破骨细胞分化能力的正调节因子。EPSTI1表达减少导致破骨细胞吸收减少。机械上,EPSTI1驱动的破骨细胞生成受NF-κB通路调控,它是由蛋白激酶R(p-PKR)的磷酸化介导的。此外，EPSTI1通过PKR/NF-κB途径参与骨质疏松的调节也在骨质疏松患者的骨样本中得到证实。
结论：总的来说，我们的研究结果表明,EPSTI1可能通过PKR/NF-κB通路调节破骨细胞分化和骨吸收,需要体内实验进一步验证EPSTI1作为骨质疏松症的治疗靶点.
