CHKA基因调控胆碱代谢途径在急性移植物抗宿主病T细胞活化中的机制研究

Recent studies have suggested that plasma-derived metabolites may be potential biomarkers relevant for acute graft-versus-host disease (aGvHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) model. However, no laboratory test can predict the risk of aGvHD after allo-HSCT. Here, we report an integrated metabolomics and transcriptomics study that identified a distinct choline metabolism signature with 38 allo-HSCT recipients with aGvHD and 45 allo-HSCT recipients but without aGvHD. We generated an aGvHD risk score (GRS) based on metabolite markers for each patient using the Least Absolute Shrinkage and Selector Operation (LASSO) logistic regression model. The GRS demonstrated predictive value for aGvHD at +15d after transplantation with positive predictive value of 92.2%A high GRS was able to predict patients with 26.4-fold increased risk for aGvHD. Pathway analysis of 1148 differentially expressed gene surrogates revealed a significantly altered choline metabolism network. Gene expressions of these lipases, especially choline kinase alpha (CHKA) were significantly altered in aGvHD samples as compared with samples from patients without aGvHD, and closely corelated with the module including RUNX, STAT, and GATA, which are vital to alloreactive T cell activation and differentiation. Thus, we propose that CHKA has a role in the pathogenesis of aGvHD by regulating alloreactive T cell activation and differentiation, which prompt the T cell differentiate to Th1 cells. In the present study, we will further identify the correlation between choline metabolism and T cell activation and differentiation. The specific function of CHKA in aGvHD will be investigated through gene, protein, cell, and on the whole. And the aberrant up-stream signal pathway regulate CHKA and T cell differentiation will be investigated through the animal model. The project will specify the function and mechanism of dysregulated choline metabolism and alloreactive T cell activation and differentiation, and provide new insight for aGvHD pathophysiology.

急性移植物抗宿主病（aGvHD）是异基因造血干细胞移植（allo-HSCT）非复发死亡（NRM）的主要原因。在前期工作中，我们对allo-HSCT患者血浆进行了代谢组学分析。结果发现，发生aGvHD的患者在移植后早期出现胆碱代谢异常，胆碱激酶（CHKA）表达显著升高，可以预警aGvHD的发生。WGCNA相关性分析发现CHKA和调控T细胞分化的转录模块密切相关。我们提出假设，CHKA可能通过胆碱代谢调控了移植后同种异基因反应的T细胞活化和分化，参与aGvHD的发生。本项目拟从分子、细胞、动物和临床水平多方面探讨CHKA-同种异基因反应T淋巴细胞活化-胆碱代谢三者之间的关系，以代谢产物为把手，揭示CHKA和同种异基因T细胞分化偏倚之间的联系。本研究将从代谢组学这个新角度揭示aGvHD的发病机制，以及代谢和同种异基因T细胞分化之间的潜在联系，为aGvHD寻找新的生物标记物奠定基础。

异基因造血干细胞移植（allogenic hematopoietic stem cell transplantation, allo-HSCT）是治疗白血病、淋巴瘤等恶性血液病的重要方法，而急性移植物抗宿主病（acute graft-versus-host disease, aGVHD）是allo-HSCT早期非复发死亡的主要原因之一。我们课题组前期对接受HLA相合的亲缘或非亲缘allo-HSCT患者血浆进行代谢组学分析发现，发生aGVHD的患者在移植后+15天胆碱代谢相关产物显著高表达。通过外周血单个核细胞转录组学发现，有8条编码甘油磷脂代谢脂酶的基因改变，其中胆碱激酶α（choline kinase α, CHKA）变化最为显著，移植后+15天外周血单个核细胞CHKA的表达可作为预测aGVHD是否发生的关键指标。为进一步探索CHKA在aGVHD状态下T细胞增殖分化中的作用，本研究通过建立小鼠aGVHD模型，采用药物抑制和基因敲除的方法下调T细胞内CHKA的表达，分析对T细胞增殖分化和aGVHD发生发展的影响，并探索CHKA调控aGVHD状态下T细胞增殖分化的信号通路。结果提示T细胞内CHKA的表达与aGVHD的发生密切相关。 aGVHD发生前和发生后T细胞内CHKA的表达均出现上调。aGVHD发生前血浆内胆碱代谢产物增加可能与T细胞内CHKA的表达上调有关。下调供体T细胞内CHKA的表达可促使CD4+T细胞向Treg细胞分化增加，抑制炎性细胞因子的分泌，促进IL-10的产生，改善aGVHD的严重程度。进一步研究提示，CHKA可能是通过调控 PI3K/AKT通路干预aGVHD状态下T细胞亚群分化。下调供体T细胞内CHKA的表达可为早期预防和治疗aGVHD提供新的思路。