小鼠骨髓间充质干细胞自噬与衰老的关系

Correlation between autophagy of bone marrow mesenchymal stem cells and aging in mice

摘要:

目的 探讨小鼠骨髓间充质干细胞（BM-MSCs）自噬与衰老的关系。方法 通过体外分离培 养年轻组小鼠（8 周龄）和老年组小鼠（18 个月龄）BM-MSCs，流式细胞术检测细胞表型，TUNEL 染色检 测细胞凋亡，ELISA 试剂盒检测BM-MSCs 分泌蛋白VEGF、bFGF、IGF-1、HGF 的表达，Western blot 检 测自噬相关蛋白LC3- Ⅰ、LC3- Ⅱ、Beclin 1、ATG12-5、p62 及信号通路蛋白p-Akt、Akt、p-mTOR、 mTOR 的表达。结果 与年轻组比较，老年组BM-MSCs 凋亡增加（P <0.05），分泌功能下降（P <0.05），自 噬相关蛋白LC3- Ⅰ、LC3- Ⅱ、Beclin 1、ATG12-5 表达水平下降（P <0.05），相反p62 蛋白表达水平升高 （P <0.05），自噬信号通路相关蛋白p-Akt、Akt、p-mTOR、mTOR 表达升高。结论 老年小鼠BM-MSCs 凋亡增加，自噬活性及旁分泌功能下降。

Abstract:

Objective To investigate the effect of autophagy of bone marrow mesenchymal stem cells (BMMSCs) on the aging process in mice. Methods BM-MSCs were isolated from the bone marrow of young (8 w) and elderly (18 m) mice respectively. BM-MSCs were cultivated in vitro , and characterized using flow cytometry. Apoptosis was detected by TUNEL staining. Meanwhile, the expressions of VEGF, bFGF, IGF-1 and HGF in the BM-MSCs were detected by ELISA kits. The expressions of autophagy-related proteins (such as LC3-I, LC3-II, Beclin 1, ATG12-5 and p62) and signal pathway proteins (such as p-Akt, Akt, p-mTOR and mTOR) were evaluated by Western blot. Results Compared with the young group, the apoptosis in the aged group was significantly increased (P < 0.05), while the secretory function was decreased (P < 0.05). Furthermore, the expressions of LC3-I, LC3-II, Beclin 1 and ATG12-5 were decreased (P < 0.05), whereas p62 was increased (P < 0.05) in the aged group. The expressions of p-Akt, Akt, p-mTOR and mTOR were increased in the aged group. Conclusions In aged mice, apoptosis of BM-MSCs increases, paracrine function and autophagy activity decrease.