PPARγ磷酸化修饰参与介导饱和脂肪酸对三种组织来源MSC诱导作用差异并影响糖尿病细胞治疗效果

Mesenchymal stem cells for the treatment of diabetes were derived from a variety of tissues. However, we know little about the differences of the curative effects of these types of MSC. Our previous study shows that the inductive effects of palmitate (PA) were significantly different in hBM-MSCs, hWJ-MSCs, and hAD-MSCs, as variations were found in the levels of PPARγ phosphorylation, the rates of cell mortality, and the expression of inflammatory cytokines. In this project, we will make further improvement and validation on that if PPARγ phosphorylation is the reason of different inductive effects and curative effects of MSC therapy. We will verify the effects of palmitate in three different tissues derived MSCs by sample addition. Our study aims to clarify the regulatory mechanisms of PPARγ phosphorylation, and investigate whether phosphorylation of PPARγ influences inhibitory effect of AMPK agonist and regulates inductive effects of PA. We will also assess therapeutic effects of three different tissues derived MSC therapy on high-fat diet (HFD)-induced type 2 diabetic (T2D) mice, and the possibility of PPARγ mutant expressed MSCs are more suitable for cell therapy. In conclusion, this research will provide theoretical basis and experimental evidence for choice of appropriate type of MSCs to be a better therapeutic strategy of T2D.

糖尿病细胞治疗临床试验研究中的间充质干细胞（MSC)来源于多种组织，治疗效果一致性差。我们的前期研究发现骨髓、脐带和脂肪组织来源MSC经饱和脂肪酸—棕榈酸酯（PA）诱导，PPARγ磷酸化水平发生不同变化，细胞死亡率和炎症因子表达量明显不同。本项目将针对PPARγ磷酸化修饰是否是PA产生不同诱导作用的重要因素及它对MSC细胞治疗的影响等问题，从PA诱导角度明确三种组织来源MSC的异同；通过化学药物处理、基因抑制和突变体表达的方式，阐明上游信号对PPARγ磷酸化水平的调控机制，研究磷酸化修饰参与AMPK激动剂的抑制作用、对下游信号和关键基因调控以及PA诱导作用的影响；观察三种组织来源MSC对血浆脂肪酸浓度升高的2型糖尿病小鼠的治疗效果，探索PPARγ突变体表达对细胞治疗的影响。本研究提出2型糖尿病细胞治疗研究中出现疗效差异的可能原因，为今后MSC组织来源的选择提供理论依据和实验基础。

糖尿病细胞治疗临床试验研究中的间充质干细胞（MSC)来源于多种组织，治疗效果一致性差。研究发现骨髓、脐带和脂肪组织来源MSC虽然细胞表面标志物表达相同，但是细胞生长速度有明显差异、脐带间充质干细胞（hWJ-MSCs）增殖速度最快，同样也表现出最高的棕榈酸酯（PA）敏感性。在PA诱导过程中，hWJ-MSCs细胞死亡率最高、炎症因子分泌量大。与PA敏感性相对应的是hWJ-MSCs细胞中AMPK、MAPK等激酶活性较高，PPARγ磷酸化水平不同。本项目采用AMPK激动剂、MAPK抑制剂和PPARγ激动剂等化学药物预处理细胞，发现这些试剂均能够不同程度的抑制PA的脂毒性，其中以AMPK激动剂的效果最为显著。在2型糖尿病模型小鼠细胞输注治疗中，我们发现骨髓来源间充质干细胞（hBM-MSCs）表现出最好的治疗效果，hWJ-MSCs效果不佳。通过改变PPARγ的磷酸化水平可部分改善hWJ-MSCs的治疗效果。本研究提出2型糖尿病细胞治疗研究中出现疗效差异的可能原因，为今后MSC组织来源的选择提供理论依据和实验基础。