Cell Biology and Toxicology ( IF 5.3 ) Pub Date : 2022-09-19 , DOI: 10.1007/s10565-022-09769-3 Yumeng Miao 1 , Xiaoqian Wu 1 , Xinru Xue 1 , Xingyu Ma 1 , Ling Yang 1 , Xi Zeng 1 , Yuxiao Hu 1 , Yue Dai 1 , Zhifeng Wei 1
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T helper (Th) 17 cells highly contribute to the immunopathology of rheumatoid arthritis. Morin, a natural flavonoid, owns well anti-arthritic action but unclear effect on Th17 differentiation. This study tried to solve this issue and explore the mechanisms in view of cellular metabolism. Naïve CD4+ T cells were treated with anti-CD3/CD28 along with Th17-inducing cytokines. Morin was shown to block Th17 differentiation without affecting cell viability even when Foxp3 was dampened. The mechanisms were ascribed to the limited fatty acid synthesis by restricting FASN transcription, as indicated by metabolomics analysis, nile red staining, detection of triglycerides, FASN overexpression, and addition of palmitic acid. Moreover, morin had slight effect on cell apoptosis and protein palmitoylation during Th17 differentiation, but blocked the binding of RORγt to promoter and CNS2 region of Il17a gene. Oleic acid rescued the inhibition of morin on RORγt function, and Th17-inducing cytokines could not induce RORγt function in SCD1-defficient cells, suggesting that oleic acid but not palmitic acid was the direct effector in the action of morin. Then, PPARγ was identified as the target of morin, and GW9662 or PPARγ CRISPR/Cas9 KO plasmid weakened its above-mentioned effects. The transrepression of FASN by morin was owing to physical interaction between PPARγ and Sp1, and the importance of Sp1 in Th17 differentiation was confirmed by siSp1. Finally, the effects and mechanisms for morin-dampened Th17 responses were confirmed in collagen-induced arthritis (CIA) mice. Collectively, morin inhibited Th17 differentiation and alleviated CIA by limiting fatty acid synthesis subsequent to PPARγ activation.
Graphical abstract
中文翻译：
Morin 是 PPARγ 激动剂，在胶原诱导的关节炎中通过限制脂肪酸合成来抑制 Th17 分化
辅助 T (Th) 17 细胞对类风湿性关节炎的免疫病理学有很大影响。桑色素是一种天然黄酮类化合物，具有良好的抗关节炎作用，但对 Th17 分化的影响尚不清楚。本研究试图解决这一问题，并从细胞代谢的角度探讨其机制。用抗 CD3/CD28 和 Th17 诱导细胞因子处理初始 CD4 + T 细胞。即使 Foxp3 受到抑制，桑色素也能阻止 Th17 分化而不影响细胞活力。代谢组学分析、尼罗红染色、甘油三酯检测、FASN 过表达和棕榈酸添加表明，该机制归因于通过限制 FASN 转录来限制脂肪酸合成。此外，桑色素对Th17分化过程中的细胞凋亡和蛋白质棕榈酰化有轻微影响，但阻断RORγt与Il17a基因启动子和CNS2区域的结合。油酸挽救了桑色素对RORγt功能的抑制作用，而Th17诱导细胞因子不能在SCD1缺陷细胞中诱导RORγt功能，这表明油酸而不是棕榈酸是桑色素作用的直接效应物。随后，PPARγ被确定为桑色素的靶点，GW9662或PPARγ CRISPR/Cas9 KO质粒削弱了其上述作用。桑色素对 FASN 的反式抑制是由于 PPARγ 和 Sp1 之间的物理相互作用，并且 siSp1 证实了 Sp1 在 Th17 分化中的重要性。最后，桑色素抑制 Th17 反应的作用和机制在胶原诱导关节炎 (CIA) 小鼠中得到证实。总的来说，桑色素通过限制 PPARγ 激活后的脂肪酸合成来抑制 Th17 分化并减轻 CIA。
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