GM-CSF诱导调节性树突样细胞在MSC抑制ARDS失控炎症反应中作用的机制研究

Acute respiratory distress syndrome (ARDS) is a common respiratory failure in critically ill patients, which still a lack of effective treatment. Our previous studies found that mesenchymal stem cells (MSCs) can effectively inhibit inflammatory response in ARDS; MSCs can induce dendritic cell (DC) differentiation to regulatory DC (DCreg); DC plays an important role in the regulation of inflammatory response in ARDS. Therefore, the induction of DCreg by MSC may be an important pathway for MSC inhibiting the excessive inflammatory response in ARDS. However, the exact mechanism is still unclear. MSC can secrete GM-CSF, an important cytokine that induces DCreg production. MAPK3 pathway is indispensable in GM-CSF-induced DCreg. Therefore, we hypothesized that GM-CSF production by MSCs paracrine could induce DCreg differentiation from DC by regulating the MAPK3 pathway, thus inhibiting the excessive inflammatory response in ARDS. The aims of this study are the following: ①To investigate the role of GM-CSF production by MSC paracrine in the generation of DCreg in vitro by application of gene silencing technology; ②To investigate the role of MAPK3 signaling pathway in DCreg differentiation by GM-CSF in vitro by application of gene knockout technology (3) To explore the role of DCreg in the anti-inflammatory effect of MSCs in ARDS by adoptive immunization of DCreg in LPS-induced ARDS mice. This study may provide a new theoretical basis and new idea for the treatment of ARDS by MSC.

ARDS是重症患者常见呼吸衰竭，目前缺乏有效治疗措施。课题组前期研究发现MSC能有效抑制ARDS炎症反应；MSC诱导DC向调节性DC（DCreg）转化；DC在调控ARDS炎症反应中具有重要作用。因此，MSC诱导DCreg生成可能是MSC抑制ARDS炎症反应重要途径，但是具体机制尚不明确。MSC可分泌诱导DCreg生成的重要细胞因子GM-CSF，MAPK3通路在GM-CSF诱导DCreg分化过程中不可或缺。由此，本研究的科研假设为MSC旁分泌GM-CSF通过调控MAPK3通路诱导DCreg的生成，进而抑制ARDS失控的炎症反应。本研究拟采用①基因沉默技术调控MSC对GM-CSF分泌，体外证实MSC旁分泌GM-CSF在诱导DCreg生成中作用；②基因敲除技术探讨MAPK3信号在GM-CSF诱导DCreg生成中作用；③构建ARDS小鼠模型阐明MSC诱导生成DCreg在调控ARDS炎症反应意义。

急性呼吸窘迫综合征是重症患者常见的呼吸衰竭，但是目前缺乏有效治疗措施。调控炎症反应是治疗急性呼吸窘迫综合征的必由之路。本研究基于间充质干细胞能有效抑制急性呼吸窘迫综合征的肺组织失控炎症反应；以及树突样细胞在调控炎症反应中具有的重要作用，探讨了间充质干细胞通过诱导调节性树突样细胞调控急性呼吸窘迫综合征肺组织炎症反应的机制。.本研究初步表明了间充质干细胞通过旁分泌方式诱导调节性树突样细胞的形成，从而降低CD4+T细胞的活化功能以及诱导调节性T细胞的形成。通过构建GM-CSF的SiRNA序列，获得低表达GM-CSF的间充质干细胞，以及应用GM-CSF拮抗剂，实验结果初步显示间充质干细胞可能是通过低表达GM-CSF诱导调节性树突样细胞。研究初步探讨了间充质干细胞诱导调节性树突样细胞的形成机制，为急性呼吸窘迫综合征的炎症调控治疗提供了新的思路。