Regulatory effect of nicotine on collagen-induced arthritis and on the induction and function of in vitro-cultured Th17 cells

Abstract

Objectives. To determine the effect of nicotine stimulation on collagen-induced arthritis (CIA), especially on Th17 cells, and the influence of activated acetylcholine receptor signaling on the induction and function of in vitro-cultured Th17 cells.

Methods. Mice were divided into control and experimental (nicotine) group, and PBS or nicotine-PBS was orally administered from Day 21 to Day 28. Phenotypic changes in spleen CD4⁺ cells were measured by flow cytometry. α7nAChR expression in Th17 cells was detected using flow cytometry, western blotting and real-time PCR. Purified Th17 cells were further stimulated with nicotine. The cytometric bead array (CBA) assay was employed to measure TNF-α levels in mice serum and IL-17A levels in the supernatants of nicotine-treated cell cultures.

Results. Compared with their counterparts, mice receiving oral nicotine showed a delayed progress of arthritis and more attenuated signs of histological changes. Moreover, serum TNFα levels were lower in the nicotine-treated group. Spleen IL-17 level of nicotine-treated mice was lower than that of the control group, and the mRNA expression of pro-inflammatory cytokines (IL-17A and IL-6) in splenocytes were also lower than that of the control group. α7nAChR expression was detected on in vitro-cultured IL-17A⁺ cells. Cells treated with 10 ^{− 6} M nicotine expressed lower IL-17A levels. Similarly, supernatants from nicotine-treated cell cultures also showed lower IL-17A levels.

Conclusions. Nicotine stimulation attenuated signs and severity of arthritis in mice. Activation of nicotine acetylcholine receptors on in vitro-cultured Th17 cells decreased their pro-inflammatory function, which may play a potential role in alleviating arthritis in mice.

Keywords:

• Acetylcholine receptors
• CD4⁺IL-17A⁺Th17 cells
• Collagen-induced arthritis

Acknowledgements

We thank the Department of Animal Science at Shanghai Jiaotong University School of Medicine for laboratory animal husbandry.

Conflict of interest

None.

This work was supported by The Shanghai Committee of Science and Technology Project, China (Grant No. 12GWZX0201, 11140902900).