Autophagy Maintains the Function of Bone Marrow Mesenchymal Stem Cells to Prevent Estrogen Deficiency-Induced Osteoporosis.
Autophagy Maintains the Function of Bone Marrow Mesenchymal Stem Cells to Prevent Estrogen Deficiency-Induced Osteoporosis.
复制标题
自噬维持骨髓间充质干细胞的功能，预防雌激素缺乏引起的骨质疏松症
作者：
Qi M;Zhang L;Ma Y;Shuai Y;Li L;Luo K;Liu W;Jin Y
理论基础：内源性骨髓间充质干细胞(BMMSCs)功能受损是骨质疏松症(OP)发生的决定性因素。最近的研究证明，自噬在维持骨骼表型方面起着重要作用。然而，自噬是否通过调节BMMSCs的功能来影响OP的发生仍不清楚。方法：用8周龄C57小鼠建立卵巢切除(OVX)诱导的OP模型和假手术模型。通过体外成骨/成脂诱导和葡聚糖硫酸钠(DSS)诱导的小鼠结肠炎模型的体内治疗，检测两种模型的BMMSCs的分化和免疫调节特性。采用实时定量聚合酶链式反应(qRT-PCR)、Western blotting、激光共聚焦显微镜和透射电子显微镜等方法检测假手术组和去卵巢组BMMSCs的自噬活性。最后，为了验证雷帕霉素、短发夹状RNA(ShRNA)-BECN1(ShBECN1)和shRNA-ATG5(ShATG5)对骨髓间充质干细胞分化的影响，我们用茜素红和油红O染色检测骨髓间充质干细胞的分化，并用Micro-CT、钙黄绿素染色和油红O染色评价骨表型。结果：OVX诱导的OP模型小鼠骨髓间充质干细胞成骨分化减少，成脂分化增强，免疫调节能力减弱。此外，骨质疏松症小鼠的骨髓和骨髓间充质干细胞中的自噬都减少了。重要的是，自噬的调节直接影响骨髓间充质干细胞的功能，包括分化和免疫调节能力。此外，雷帕霉素治疗挽救了内源性BMMSCs的功能，并减轻了OVX小鼠的骨质疏松表型。结论：自噬调节BMMSCs的再生功能，控制OP的发生发展。雷帕霉素对自噬的恢复可能为骨质疏松症的治疗提供一种有效的方法。
Rationale: The impaired function of endogenous bone marrow mesenchymal stem cells (BMMSCs) is a determinant in the development of osteoporosis (OP). Recent researches have proved that autophagy plays an important role in maintenance of skeletal phenotype. However, whether autophagy affects the development of OP through regulating the function of BMMSCs remains elusive. Methods: Ovariectomy (OVX)-induced OP model and sham model were established in 8-week-old C57 mice. The differentiation and immunoregulation properties of BMMSCs from two models were examined by osteogenic/adipogenic induction in vitro and treatment of a dextran sulfate sodium (DSS)-induced mice colitis model in vivo. We evaluated autophagy activity in sham and OVX BMMSCs by quantitative real time-polymerase chain reaction (qRT-PCR), western blotting, laser confocal microscopy and transmission electron microscopy (TEM). Finally, to testify the effects of rapamycin, short hairpin RNA (shRNA) -BECN1 (shBECN1) and shRNA-ATG5 (shATG5), we performed Alizarin Red staining and Oil Red O staining to detect lineage differentiations of BMMSCs, and carried out micro-CT, calcein staining and Oil Red O staining to assess the skeletal phenotype. Results: BMMSCs from OVX-induced OP model mice exhibited decreased osteogenic differentiation, increased adipogenic differentiation and impaired immunoregulatory capacity. Furthermore, autophagy decreased both in bone marrow and BMMSCs of osteoporotic mice. Importantly, regulation of autophagy directly affects the functions of BMMSCs, including differentiation and immunoregulatory capacities. Moreover, treatment with rapamycin rescued the function of endogenous BMMSCs and attenuated the osteoporotic phenotype in OVX mice. Conclusion: Our findings suggest that autophagy regulates the regenerative function of BMMSCs and controls the development of OP. The restoration of autophagy by rapamycin may provide an effective therapeutic method for osteoporosis.