Involvement of transient receptor potential melastatin-8 (TRPM8) in menthol-induced calcium entry, reactive oxygen species production and cell death in rheumatoid arthritis rat synovial fibroblasts.
Rheumatoid arthritis is most prominently characterized by synoviocyte hyperplasia which therefore serves as an important target for clinical therapy. In the present study, it was observed that menthol, the specific agonist of transient receptor potential melastatin subtype 8 (TRPM8), could induce sustained increases of cytosolic calcium concentration ([Ca(2+)]c) in synoviocytes isolated from collagen-induced arthritis rats in dose-dependent manner, which was evidently blocked by applying an extracellular Ca(2+)-free buffer. Menthol-induced [Ca(2+)]c increase was also significantly inhibited by potent TRPM8 antagonist capsazepine (CZP), indicating that this [Ca(2+)]c elevation was mostly attributed to TRPM8-mediated Ca(2+) entry. Besides, RT-PCR indeed demonstrated presence of TRPM8 in the synoviocytes. Meanwhile, it was found that menthol evoked production of intracellular reactive oxygen species, which could be abolished by Ca(2+) free solutions or CZP. Further experiments showed that menthol reduced the cell numbers and survival of synoviocytes. This reduction was associated with apoptosis as suggested by mitochondrial membrane depolarization, nuclear condensation and a caspase 3/7 apoptotic assay. Menthol-induced death and apoptosis of synoviocytes both were obviously inhibited by CZP, intracellular calcium chelator BAPTA-AM, and reactive oxygen species inhibitor diphenylene iodonium, respectively. Taken together, our data indicated that menthol resulted in synoviocyte death associated with apoptosis via calcium entry and reactive oxygen species production depending on TRPM8 activation.
School of Physics and TEDA Applied Physics Institute, Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin, China.
Shuyan
S
Zhu
School of Physics and TEDA Applied Physics Institute, Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin, China.
Yuxiang
Y
Wang
School of Physics and TEDA Applied Physics Institute, Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin, China. Electronic address: plt@nankai.edu.cn.
Leiting
L
Pan
School of Physics and TEDA Applied Physics Institute, Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin, China.
Shuang
S
Yang
School of Physics and TEDA Applied Physics Institute, Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin, China.
Yonglin
Y
Sun
School of Physics and TEDA Applied Physics Institute, Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin, China.
Xinyu
X
Wang
School of Physics and TEDA Applied Physics Institute, Key Laboratory of Bioactive Materials of Education Ministry, Nankai University, Tianjin, China. Electronic address: hufen@nankai.edu.cn.
Fen
F
Hu
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation / Q000187:drug effects; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008610:Menthol / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013583:Synovial Membrane / Q000473:pathology*; D050053:TRPM Cation Channels / Q000819:agonists / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D050053:TRPM Cation Channels; C498947:Trpm8 protein, rat; D008610:Menthol; D053148:Caspase 3; D053179:Caspase 7; D002118:Calcium
Apoptosis; Calcium; Menthol; Reactive oxygen species; Synoviocytes; TRPM8