LRNA9884调控Mincle维持M1巨噬细胞表型：急性肾损伤后炎症释放的机制研究

Macrophages are key inflammatory cells that play a critical role in renal inflammation and repair after acute kidney injury (AKI). In our previous study, we found 1) Novel lncRNA_9884 (LRNA9884) was highly expressed in cisplatin-induced AKI kidney; 2) The expression of LRNA9884 was largely upregulated by TNF-α stimulation in bone marrow–derived macrophages (BMDMs); 3) Knockdown of LRNA9884 in BMDMs inhibited the expression of Mincle, which is a specific macrophage receptor induced on the cytomembrane and is responsible for maintaining inflammatory phenotypes of M1 macrophages during the progress of AKI. Hereby, we put forward to the hypothesis that LRNA9884 promotes the inflammatory response via enhancing Mincle-dependent M1 macrophage phenotype maintenance after AKI injury. In the proposed study, we would employ two mouse AKI models including cisplatin-induced and ischemia reperfusion-induced models, and fully utilize cultured BMDMs by using multiple molecular biological techniques to 1) Validate the relationship between LRNA9884 expression and macrophage polarization in AKI; 2) Uncover the biological function of LRNA9884 in macrophage polarization and function; 3) Uncover the molecular mechanism by which LRNA9884 regulates Mincle in vivo and in vitro. This study will shed new lights on the understanding of pathological role of novel LRNA9884 in AKI.

炎性巨噬细胞M1持续性聚集、释放炎性介质并诱导炎症反应和组织损伤是急性肾损伤（AKI）进展的重要因素。我们前期数据显示，长链非编码RNA9884（LRNA9884）在小鼠AKI模型的肾脏中表达明显升高；骨髓来源巨噬细胞中LRNA9884的表达可以被炎症刺激诱导；下调LRNA9884能减少巨噬细胞的表面膜蛋白C型凝集素Mincle的表达，从而减少M1巨噬细胞聚集。据此我们认为，LRNA9884是一促进AKI的关键调控因素，它上调巨噬细胞的Mincle蛋白，维持M1巨噬细胞表型持续促进炎症释放。本课题拟用AKI小鼠模型结合体外培养骨髓来源巨噬细胞，1）明确AKI模型中，LRNA9884的表达变化及与巨噬细胞的相关性。2）细胞层面揭示LRNA9884在巨噬细胞中的生物学功能。3）基因层面阐明LRNA9884在巨噬细胞中对与Mincle的调控机制。本研究拟进一步为AKI的治疗提供新的靶点。

项目背景.急性肾损伤（AKI）是临床常见的危重症，我国的流行病学资料显示每年至少有300万例成年AKI患者住院治疗，其中约70万例死亡，存活的患者中约2/3发生慢性肾脏病，探讨AKI发生发展的分子机制并有效进行阻断是预防其进展的关键环节。我们前期数据显示，长链非编码RNA9884（LRNA9884）在小鼠AKI模型的肾脏中表达明显升高；骨髓来源巨噬细胞中LRNA9884的表达可以被炎症刺激诱导；下调LRNA9884能减少巨噬细胞的表面膜蛋白C型凝集素Mincle的表达，从而减少M1巨噬细胞聚集。本研究拟进一步通过细胞及动物实验针对LRNA9884在AKI中的功能及机制进行深入研究，为AKI的治疗提供新的依据。.主要研究内容.1）炎症刺激肾小管上皮细胞及巨噬细胞后LRNA9884表达水平变化；.2）肾小管上皮细胞下调LRNA9884后下游炎症及MIF表达变化；.3）巨噬细胞下调LRNA9884后对于急性肾损伤后巨噬细胞表型的影响；.4）AKI小鼠特异性下调LRNA9884后肾脏转归。.重要结果及数据.1）顺铂诱导急性肾损伤小鼠模型中，肾脏LRNA9884表达增加，主要位于肾小管上皮细胞及巨噬细胞；.2）IL-1β体外刺激肾小管上皮细胞LRNA9884及炎症指标表达上调，下调LRNA9884后炎症指标表达下降；.3）LRNA9884通过巨噬细胞移动抑制因子（MIF）促进炎症释放；.4）LRNA9884在巨噬细胞中通过调节Mincle维持M1巨噬细胞表型；.5）急性肾损伤的小鼠中在巨噬细胞中特异性下调LRNA9884可减少M1巨噬细胞浸润。.科学意义.1）关于LRNA9884在急性肾损伤中的功能及其调控机制为本研究组首次报道。.2）项目发现急性肾损伤后其在肾脏固有细胞及浸润的免疫细胞中均具有促进炎症效应的作用，LRNA9884可调控AKI后的炎症表达，可能成为急性肾损伤潜在的治疗靶点。