肾小管上皮细胞主动调控巨噬细胞微环境在急性肾损伤-慢性化(AKI-CKD)中的作用和干预策略

Acute kidney injury (AKI) progressing to chronic kidney disease (CKD) was newly recognized as an interconnected syndrome. Macrophages (Mø) are integral in ischemia/reperfusion injury (I/R) incited acute kidney injury (AKI) that leads to fibrosis and chronic renal disease (CKD). However, renal Mø are heterogeneous due to their phenotype plasticity in complex renal microenvironments. Depletion of Mø likes a two-side sword, improving renal fibrosis but delaying tubular repair. Therefore, it needs to be a much greater understanding of the therapeutic targets of renal Mø. Our recent studies have demonstrated that CSF-1, IL-34 and CSF-2 generated by tubular epithelial cells (TEC) creating distinct tissue microenvironments in different disease stages from AKI to CKD, mediate long time Mø survival and proliferation, but also have distinct features in renal repair and destruction by mediating Mø phenotype differentiation in different disease status. We hypothesize that the correction of the aberrant macrophages phenotypes by time point CSF-1, IL-34 and CSF-2 depletion could inhibit Mø mediated early-onset renal fibrosis and kidney destruction. To test this hypothesis, using TEC conditional CSF-1, IL-34 or CSF-2 knockout mice in I/R and adriamycin induced AKI compared to normal mice, we will determine whether: (A) Mø phenotypes are aberrant and skewed towards “destroyers” and defective in shifting towards “healers”, thereby driving the onset of AKI progressing to CKD; (B) protective Mø and aberrant Mø are distinct results of CSF-1, IL-34 and CSF-2 released by TEC in different disease stages of AKI and CKD; (C) Targeting CSF-1, IL-34 and CSF-2 in different TEC status will improve “healers” shifting and inhibit “destroyers” shifting of Mø, and ameliorate Mø mediated abnormal repair during AKI to CKD progression; (D) one specific gene or a small group of genes control the Mø phenotype shifting towards “healers” or “destroyers”, and who is it; (E) By inhibition of the target gene in Mø, Mø can be genetically engineered to anti-inflammatory or tissue repair phenotype as “healers”, and finally inhibit early-onset renal fibrosis and promote renal repair, which will offer novel therapeutic strategies to suppress AKI transitioning to CKD.

急性肾损伤-慢性化（AKI-CKD）是目前肾脏病领域的新挑战，其发病机制被认为与浸润肾间质的主要细胞--巨噬细胞(Mø)密切相关。然而，直接清除Mø是一把双刃剑，抑制纤维化却延缓了肾脏修复，是目前亟待解决的科学问题。我们前期研究证实，肾脏Mø增殖依赖肾小管上皮细胞主动分泌的巨噬细胞生存因子CSF-1，IL-34和CSF-2，它们形成肾脏Mø微环境，在AKI和CKD的不同阶段选择性调节Mø的激活和分化。本项目拟利用可诱导性肾小管上皮细胞基因敲除技术，在AKI向CKD转化的初期或慢性持续期，时间选择性地敲除肾小管上皮细胞CSF-1或IL-34或CSF-2，既保留修复性Mø又抑制促慢性化型Mø的活化，并在此基础上借助基因芯片明确Mø表型迁移的“扳机基因”，进而通过靶向Mø“扳机基因”和巨噬细胞生存因子治疗，阻断或逆转AKI-CKD，为AKI-CKD发病机制提供新的理论依据，探索新的防治途径

急性肾损伤慢性化急性肾损伤-慢性化（AKI-CKD）是目前肾脏病领域的热点及难点，其慢性化进展认为与肾间质浸润的巨噬细胞(Mø)密切相关。肾脏Mø分化高度依赖肾脏肾小管上皮细胞主动分泌的IL-34等组成的肾脏微环境。通过干预肾小管上皮细胞IL34的表达调控巨噬细胞分化有望实现逆转或延缓AKI慢性化的目标。. 通过建立可诱导性肾小管上皮细胞IL34基因敲除及敲入模型，时间选择性地敲入及敲除肾小管上皮细胞IL-34，明确IL-34构成的巨噬细胞微环境刺激巨噬细胞向M2型巨噬细胞表型迁移，及其在急性肾损伤不可逆性进展中的作用；流式分选上述在体肾脏巨噬细胞，结合基因芯片分析，明确肾损伤持续进展中，IL-34对巨噬细胞基因表达谱的影响，寻找其调控M2型巨噬细胞表型的干预靶点；并验证通过干预靶点M2型巨噬细胞对急性肾损伤的慢性化和纤维化的抑制，为抑制急性肾损伤向终末期进展找到新的治疗途径；明确干预靶点M2型巨噬细胞亚型对AKI慢性化早期预测和预防的意义。. 本项目明确IL34对巨噬细胞活化状态的调节效应和信号机制，可通过调控靶点M2型巨噬细胞亚型干预AKI慢性化，为AKI-CKD发病机理提供新理论基础，为防治AKI-CKD转归探索出新途径。