Ke Jiang-Tao, Zhang Heng, Bu Yan-Hong, Gan Pei-Rong, Chen Fang-Yuan, Dong Xin-Tong, Wang Yan, Wu Hong
Key Laboratory of Xin'an Medicine, Ministry of Education, Hefei, China.
College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China.
Front Pharmacol. 2022 Jul 22;13:969408. doi: 10.3389/fphar.2022.969408. eCollection 2022.
Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by a joint hypoxia microenvironment. Our previous untargeted metabolomics study found that sphingolipid (SPL) metabolism was abnormal in the joint synovial fluid samples from adjuvant arthritis (AA) rats. Geniposide (GE), an iridoid glycoside component of the dried fruit of Ellis, is commonly used for RA treatment in many Asian countries. At present, the mechanism of GE in the treatment of RA, especially in the joint hypoxia microenvironment, is not entirely clear from the perspective of SPL metabolism. The purpose of this research was to explore the potential mechanism of abnormal SPL metabolism in RA joint hypoxia microenvironment and the intervention effect of GE, through the untargeted metabolic analysis based on the ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS). Arthritis index, foot swelling and histopathology were used to assess whether the AA rat model was successfully established. The SPLs extracts collected from AA rats' synovial tissue, serum and rheumatoid arthritis synovial fibroblasts (RASFs, MH7A cells, hypoxia/normoxia culture) were analyzed by metabolomics and lipdomics approach based on UPLC-Q-TOF/MS, to identify potential biomarkers associated with disorders of GE regulated RA sphingolipid metabolism. As a result, 11 sphingolipid metabolites related to RA were screened and identified. Except for galactosylceramide (d18:1/20:0), GE could recover the change levels of the above 10 sphingolipid biomarkers in varying degrees. Western blotting results showed that the changes in ceramide (Cer) level regulated by GE were related to the down-regulation of acid-sphingomyelinase (A-SMase) expression in synovial tissue of AA rats. To sum up, this research examined the mechanism of GE in the treatment of RA from the perspective of SPL metabolism and provided a new strategy for the screening of biomarkers for clinical diagnosis of RA.
类风湿关节炎（RA）是一种以关节缺氧微环境为特征的慢性炎症性疾病。我们之前的非靶向代谢组学研究发现，佐剂性关节炎（AA）大鼠关节滑液样本中的鞘脂（SPL）代谢异常。栀子苷（GE）是栀子干燥果实中的一种环烯醚萜苷成分，在许多亚洲国家常用于治疗RA。目前，从SPL代谢的角度来看，GE治疗RA的机制，尤其是在关节缺氧微环境中的机制尚不完全清楚。本研究的目的是通过基于超高效液相色谱-四极杆飞行时间质谱（UPLC-Q-TOF/MS）的非靶向代谢分析，探讨RA关节缺氧微环境中SPL代谢异常的潜在机制以及GE的干预作用。采用关节炎指数、足肿胀和组织病理学评估AA大鼠模型是否成功建立。通过基于UPLC-Q-TOF/MS的代谢组学和脂质组学方法，分析从AA大鼠滑膜组织、血清和类风湿关节炎滑膜成纤维细胞（RASFs，MH7A细胞，缺氧/常氧培养）中收集的SPL提取物，以鉴定与GE调节的RA鞘脂代谢紊乱相关的潜在生物标志物。结果，筛选并鉴定出1种与RA相关的鞘脂代谢物。除半乳糖神经酰胺（d18:1/20:0）外，GE可不同程度地恢复上述10种鞘脂生物标志物的变化水平。蛋白质印迹结果表明，GE调节的神经酰胺（Cer）水平变化与AA大鼠滑膜组织中酸性鞘磷脂酶（A-SMase）表达下调有关。综上所述，本研究从SPL代谢的角度探讨了GE治疗RA的机制，为RA临床诊断生物标志物的筛选提供了新策略。
