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TNF-α induces expression of the circadian clock gene Bmal1 via dual calcium-dependent pathways in rheumatoid synovial cells

Authors :
Kenta Kaneshiro
Teppei Hashimoto
Yoshitada Sakai
Kohjin Suzuki
Ayako Nakai
Nao Shibanuma
Kohsuke Yoshida
Koji Tateishi
Natsuko Nakagawa
Koto Uchida
Yoshiko Kawasaki
Akira Hashiramoto
Naonori Hashimoto
Source :
Biochemical and Biophysical Research Communications. 495(2):1675-1680
Publication Year :
2018
Publisher :
Elsevier, 2018.

Abstract

Tumor necrosis factor (TNF)-α is responsible for expressions of several clock genes and affects joint symptoms of rheumatoid arthritis (RA) with diurnal fluctuation. We tried to determine the mechanism involved in over-expression of Bmal1, induced by TNF-α, in primary cultured rheumatoid synovial cells. Cells were incubated with intra-cellular Ca2+ chelator BAPTA-AM, calcineurin inhibitor FK506 and p300/CBP (CREB binding protein) inhibitor C646, respectively, or transfected with p300 and CBP small interfering RNA (siRNA) before stimulation with TNF-α. Oscillation phase and amplitude of Bmal1, transcriptional activator Rorα, transcriptional repressor Rev-erbα, and histone acetyltransferases (p300 and Cbp) were evaluated by quantitative real-time PCR. As results, TNF-α did not influence the oscillation phase of Rev-erbα, while enhanced those of Rorα, resulting in over-expression of Bmal1. When Ca2+ influx was inhibited by BAPTA-AM, TNF-α-mediated up-regulation of Rorα was cancelled, however, that of Bmal1 was still apparent. When we further explored another pathway between TNF-α and Bmal1, TNF-α suppressed the expression of Rev-erbα in the absence of Ca2+ influx, as well as those of p300 and Cbp genes. Finally, actions of TNF-α, in increasing Bmal1/Rorα and decreasing Rev-erbα, were cancelled by C646 treatment or silencing of both p300 and Cbp. In conclusion, we determined a novel role of TNF-α in inducing Bmal1 via dual calcium dependent pathways; Rorα was up-regulated in the presence of Ca2+ influx and Rev-erbα was down-regulated in the absence of that. Results proposed that inhibition of p300/CBP could be new therapeutic targets for RA.

Details

Language :
English
ISSN :
0006291X
Volume :
495
Issue :
2
Database :
OpenAIRE
Journal :
Biochemical and Biophysical Research Communications
Accession number :
edsair.doi.dedup.....38a170b589b666074c2812ca4cef4058