RHEUMATOID ARTHRITIS SYNOVIAL MICROENVIRONMENT INDUCES METABOLIC AND FUNCTIONAL ADAPTATIONS IN DENDRITIC CELLS. RHEUMATOID ARTHRITIS SYNOVIAL MICROENVIRONMENT INDUCES METABOLIC AND FUNCTIONAL ADAPTATIONS IN DENDRITIC CELLS

Rheumatoid Arthritis (RA) is a chronic autoimmune disease which causes degradation of cartilage and bone. It is well appreciated that the pathogenic hallmark of RA is the mass influx of inflammatory cells into the joint. However, the role dendritic cells (DC) may play in this inflammatory milieu is still relatively unexplored. Moreover, the contribution this unique synovial microenvironment has on DC function and maturation is still unknown. Using monocyte-derived DC (MoDC), we established an in vitro model to recapitulate the synovial microenvironment to explore DC maturation. MoDC treated with conditioned media from ex vivo synovial tissue biopsy cultures (ECM) have increased expression of proinflammatory cytokines, chemokines and adhesion molecules. ECM treated DC have increased expression of CD83 and CCR7 and decreased expression of CCR5 and phagocytic capacity, suggestive of heightened DC maturation. ECM induced maturation is concomitant with altered cellular bioenergetics, whereby increased expression of glycolytic genes and increased glucose uptake are observed in ECM treated DC. Collectively, this results in a metabolic shift in DC metabolism in favor of glycolysis. These adaptations are in-part mediated via STAT3 as demonstrated by decreased expression of proinflammatory cytokines and glycolytic genes in ECM treated DC in response to STAT3 inhibition. Finally, to translate this data to a more in vivo clinically relevant setting, we interrogated a previously published synovial DC dataset and identified enhanced expression of glycolytic genes in synovial DC compared to DC in circulation. Collectively, our data suggests that the synovial microenvironment in RA contributes to DC maturation and metabolic reprogramming. Overall design: 9 samples

类风湿关节炎（Rheumatoid Arthritis, RA）是一种可导致软骨与骨骼退变的慢性自身免疫性疾病。学界普遍认为，RA的致病特征为炎症细胞大量浸润关节组织。然而，树突状细胞（dendritic cells, DC）在该炎症微环境中可能发挥的作用仍尚未得到充分探索。此外，独特的滑膜微环境对DC功能与成熟度的调控贡献目前仍不明晰。本研究采用单核细胞衍生树突状细胞（monocyte-derived DC, MoDC）构建了可重现滑膜微环境的体外模型，以探究DC的成熟过程。经外植体滑膜组织活检培养条件培养基（ECM）处理的MoDC，其促炎细胞因子、趋化因子与黏附分子的表达水平显著升高。经ECM处理的DC中，CD83与CCR7的表达量上调，而CCR5的表达及吞噬能力则出现下调，提示DC成熟度升高。ECM诱导的DC成熟伴随细胞生物能学的改变，具体表现为ECM处理后的DC中糖酵解相关基因表达上调、葡萄糖摄取增加，最终导致DC代谢向糖酵解方向发生代谢转换。上述适应性变化部分由信号转导与转录激活因子3（STAT3）介导：抑制STAT3后，ECM处理的DC中促炎细胞因子与糖酵解相关基因的表达量均出现下降。为将该研究结果转化至更贴近临床的体内场景，本研究分析了已发表的滑膜DC数据集，发现相较于循环中的DC，滑膜DC的糖酵解相关基因表达显著上调。综上，本研究数据表明，RA患者的滑膜微环境可促进DC成熟与代谢重编程。实验设计概况：9份样本