自噬调控脂肪来源间充质干细胞保护急性肺损伤中的作用及机制研究

The therapeutic strategies for acute lung injury (ALI) are still very sparse and the mortality remains high. Previous studies suggest that mesenchymal stem cells (MSC) are proposed as a promising cell therapy for ALI by paracrine action, while the detailed molecular mechanisms underlying this reaction remain incompletely understood. We have recently observed ADSC (adipose-derived mesenchymal stem cells) alleviated inflammatory responses and tissue damage against lipopolysaccharide (LPS)-induced ALI. Following co-culture with alveolar epithelial cells, LC3B-/- ADSC exhibited significantly lower levels of anti-inflammatory mediators, while notably increased the LPS-induced inflammation. These results indicated that autophagy might promote anti-inflammatory effects of ADSC. This project will further explore the effects and molecular mechanisms of autophagy in regulation of anti-inflammatory function of ADSC in models of LPS-induced ALI. We will isolate primary mouse ADSC from LC3B or Becn1 knockout mice or utilize autophagy inhibitors to treat ADSC. We will co-culture them with alveolar epithelial cells to investigate underlying mechanisms of autophagy in modulating the anti-inflammatory effects of ADSC. In vivo we will transfer these ADSC in the LPS-induced ALI models. This project aims to clarify the role and mechanisms of autophagy in regulation of the anti-inflammatory effects of ADSC in ALI, which should provide novel targets and experimental evidence for the treatment of ALI.

急性肺损伤（ALI）死亡率高，目前尚无有效的治疗方法。许多研究表明间充质干细胞能通过旁分泌效应潜在治疗ALI，但干细胞自身调控其抗炎作用的分子机制尚未完全明确。我们新近发现，脂肪来源间充质干细胞（ADSC）能减轻脂多糖诱导的炎性反应和小鼠ALI，而细胞自噬相关基因LC3B敲除小鼠来源的ADSC中抗炎介质表达下降，其与肺泡上皮细胞共培养后脂多糖诱导的炎症反应增加，提示自噬能促进ADSC的抗炎效果。本项目拟在此基础上进一步从体内体外模型明确自噬在促进ADSC保护急性肺损伤中的抗炎作用及分子机制。我们拟提取LC3B或Becn1敲除小鼠ADSC或利用自噬抑制剂干预ADSC，与肺泡上皮细胞共培养并建立体外感染模型，动物模型中我们拟利用ADSC过继等方法研究其对ALI的保护作用。本项目预期阐明细胞自噬调控ADSC抗炎效应的作用和分子机制，为ALI的治疗提供新的靶点和前期实验依据。

在国家自然科学基金项目经费资助下，课题组基本按原课题计划书顺利完成本项目研究。我们成功分离并鉴定脂肪间充质干细胞（ADSC），并通过动物实验证明ADSC可以缓解脂多糖（LPS）诱导的急性肺损伤（ALI）中的炎症反应和组织损伤。机制上，我们发现敲除Becn-1可以降低ADSC对LPS诱导肺损伤的保护作用；抑制自噬可以降低ADSC的抗炎作用，相反促进自噬可以提高ADSC的抗炎作用。综上研究表明，ADSC 对LPS 诱导ALI 起保护作用,且自噬在维持ADSC的治疗效果中起着关键作用。因此，ADSC可能成为治疗急性肺损伤的新策略。目前已经整理成文，并投稿Stem Cell Research & Therapy杂志。