Hiromichi Yoshimatsu1, Fumiyasu Okazaki, Ichiro Ieiri, Hideto To. 1. Clinical Pharmacokinetics, Division of Clinical Pharmacy, Department of Medico-Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences, Kyushu University , Fukuoka , Japan and.
Abstract
OBJECTIVE: Morning stiffness and plasma cytokine levels in rheumatoid arthritis (RA) patients exhibit 24-hour variations. Tumor necrosis factor-α (TNF-α) plays a central role in RA clinical conditions, including the invasion of inflammatory cells, destruction of cartilage, systemic inflammatory response and its levels show a 24-hour rhythm after the onset of RA. In this study, we investigated what cytokines and/or transcriptional factors are involved in the formation of 24-hour variations in TNF-α levels after the onset of RA using MRL/Mpj-Tnfrsf6(lpr) (MRL/lpr) mice. METHOD: Blood was drawn at six different times from MRL/lpr mice to measure cytokines, serum amyloid A (SAA), IgG rheumatoid factor (IgG-RF) and corticosterone levels. Cytokine and transcriptional factor levels at the different times were measured in 10- and/or 15-week-old MRL/lpr mice. The promoter activity of TNF-α by lymphotoxins (LTs) was investigated using a dual-luciferase assay. RESULTS: SAA and TNF-α concentrations clearly exhibited 24-hour rhythms with higher levels at the light phase and lower levels at the dark phase after RA crisis. The expression of LT-α and LT-β showed significant 24-hour rhythms in 15-week-old MRL/lpr mice and the phases of LT-α and LT-β levels were antiphase compared with that of TNF-α. AP-1 binding sites were found in LT-α and LT-β promoter regions, and jun mRNA expression corresponded to LT-α and LT-β levels. TNF-α promoter activity was decreased due to the co-transfection of LT-α and LT-β. CONCLUSION: LT-α and LT-β controls the 24-hour rhythm in TNF-α levels after the onset of RA in order to suppress TNF-α promoter activity.
OBJECTIVE: Morning stiffness and plasma cytokine levels in rheumatoid arthritis (RA) patients exhibit 24-hour variations. Tumor necrosis factor-α (TNF-α) plays a central role in RA clinical conditions, including the invasion of inflammatory cells, destruction of cartilage, systemic inflammatory response and its levels show a 24-hour rhythm after the onset of RA. In this study, we investigated what cytokines and/or transcriptional factors are involved in the formation of 24-hour variations in TNF-α levels after the onset of RA using MRL/Mpj-Tnfrsf6(lpr) (MRL/lpr) mice. METHOD: Blood was drawn at six different times from MRL/lprmice to measure cytokines, serum amyloid A (SAA), IgG rheumatoid factor (IgG-RF) and corticosterone levels. Cytokine and transcriptional factor levels at the different times were measured in 10- and/or 15-week-old MRL/lprmice. The promoter activity of TNF-α by lymphotoxins (LTs) was investigated using a dual-luciferase assay. RESULTS:SAA and TNF-α concentrations clearly exhibited 24-hour rhythms with higher levels at the light phase and lower levels at the dark phase after RA crisis. The expression of LT-α and LT-β showed significant 24-hour rhythms in 15-week-old MRL/lprmice and the phases of LT-α and LT-β levels were antiphase compared with that of TNF-α. AP-1 binding sites were found in LT-α and LT-β promoter regions, and jun mRNA expression corresponded to LT-α and LT-β levels. TNF-α promoter activity was decreased due to the co-transfection of LT-α and LT-β. CONCLUSION: LT-α and LT-β controls the 24-hour rhythm in TNF-α levels after the onset of RA in order to suppress TNF-α promoter activity.
Authors: Xiang Zeng; Jing-Yan Shan; Yang Liu; Yan-Hua Ning; Xue-Jian Xie; Yu-Yan Shen; Jie Song; Yun Li Journal: Nan Fang Yi Ke Da Xue Xue Bao Date: 2016-02-20