脂肪干细胞来源外泌体携带miR-27抑制白色脂肪的棕色化

目的 探讨脂肪干细胞（ASC）来源的外泌体在白色脂肪棕色化中的作用。方法 分离培养并鉴定小鼠ASC细胞；慢病毒转染构建过表达 miR-27的 ASC细胞；超高速离心提取正常及过表达 miR-27的 ASC细胞分泌的外泌体，实时荧光定量核酸扩增（qRT-PCR）分析外泌体中 miR-27的表达量；高脂喂食构建肥胖小鼠模型，分别注射过表达 miR-27外泌体（过表达组）、正常 ASC外泌体（正常表达组）及生理盐水（对照组），在寒冷暴露条件下监测体质量变化；剥离小鼠附睾皮下脂肪组织和肩胛骨脂肪组织，比较组织大小，蛋白免疫印迹法（Western blot）检测解偶联蛋白 1（UCP1）、过氧化物酶体增殖剂激活受体 γ（PPARγ）、含 PR结构域的锌指蛋白 16（PRDM16）、过氧化物酶体增殖子激活受体 γ共激活因子 1α（PGC-1α）的表达。结果 成功提取 ASC及其外泌体，并成功转染 miR-27；ASC及其外泌体中的 miR-27显著高于白色脂肪组织（P＜0.05）。与对照组相比，过表达组及正常表达组的小鼠体质量下降幅度小，随时间的增加效果更加明显（P＜0.05）。过表达组及正常表达组的小鼠的附睾皮下脂肪组织较对照组的小鼠要稍大；而肩胛骨脂肪组织的大小无明显变化。正常表达组与过表达组的 UCP1、PPARγ、PRDM16及 PGC-1α的表达水平较对照组下降（P＜0.05）。结论 脂肪干细胞来源外泌体能够抑制白色脂肪细胞的棕色化。

Adipose stem cell-derived exosomes carry miR-27 to inhibit browning of white adipose

Objective To investigate the role of adipose-derived stem cell (ASC) -derived exosomes in white fat browning. Methods The mouse ASC cells were isolated, cultured and identified. Lentivirus transfection was used to construct ASC cells overexpressing miR-27. The exosomes secreted by overexpression ASC cells were extracted by differential gradient ultra-high speed centrifugation. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to analyze the expression of miR-27 in exosomes. High-fat feeding was used to construct obese mouse models. The exosomes overexpressing miR-27 (overexpression group), normal ASC exosomes (normal expression group) and physiological saline(control group) were injected separately. The body weight changes were detected under cold exposure conditions. The epidermal subcutaneous fat tissues and scapular fat tissues of mice were striped and compared between the three groups.Western blot assay was used to detect uncoupling protein1 (UCP1), peroxisome proliferators-activated receptor γ (PPARγ),positive regulatory domain zinc finger protein 16 (PRDM16) and peroxisome proliferators-activated receptor γ coactivator-1α (PGC-1α) expressions. Results ASC and its exosomes were successfully extracted and transfected with miR-27. The expressions of miR-27 were significantly higher in ASC and its exosomes than those in white adipose tissues (P＜0.05).Compared with the control group, the body weights of mice decreased slightly in the overexpression group and the normal expression group, and the effect was more obvious with time (P＜0.05). The epididymal subcutaneous adipose tissues were slightly larger in the overexpression group and the normal expression group than those in the control group, while there were no significant changes in the scapular adipose tissues between three groups. The expression levels of UCP1, PPARγ,PRDM16 and PGC-1α were significantly lower in the normal expression group and the overexpression group than those in the control group (P＜0.05). Conclusion Adipose stem cell-derived exosomes can inhibit the browning of white adipose cells.