Open AccessCilostazol enhances apoptosis of synovial cells from rheumatoid arthritis patients with inhibition of cytokine formation via Nrf2‐linked heme oxygenase 1 induction
Author(s) -
Park So Youn,
Lee Sung Won,
Shin Hwa Kyoung,
Chung Won Tae,
Lee Won Suk,
Rhim Byung Yong,
Hong Ki Whan,
Kim Chi Dae
Publication year - 2010
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.27291
Subject(s) - heme oxygenase , copp , cilostazol , zinc protoporphyrin , chemistry , apoptosis , microbiology and biotechnology , small interfering rna , tumor necrosis factor alpha , synovial membrane , pharmacology , cancer research , transfection , medicine , arthritis , biology , heme , biochemistry , enzyme , aspirin , gene
Objective To assess the effects of cilostazol in inhibiting proliferation and enhancing apoptosis in synovial cells from patients with rheumatoid arthritis (RA). Methods Synovial cell proliferation was measured by MTT assay. The expression of NF‐κB, IκBα, Bcl‐2, Bax, heme oxygenase 1 (HO‐1), and Nrf2 was determined by Western blotting. Results Cilostazol suppressed synovial cell proliferation by arresting the G 2 /M phases of the cell cycle, and this was reversed by KT5720, an inhibitor of protein kinase A. Cilostazol increased the number of TUNEL‐positive cells, with increased cytochrome c release and apoptosis‐inducing factor translocation as well as increased caspase 3 activation. Cilostazol (10 μ M ) and cobalt protoporphyrin IX (CoPP) increased HO‐1 messenger RNA and protein expression. These effects were suppressed by zinc protoporphyrin IX (ZnPP), an HO‐1 inhibitor. Cilostazol and CoPP significantly increased IκBα in the cytosol and decreased NF‐κB p65 expression in the nucleus. Increased expression of tumor necrosis factor α (TNFα), interleukin‐1β (IL‐1β), and IL‐6 induced by lipopolysaccharide was attenuated by cilostazol and CoPP, and this was reversed by ZnPP. In mice with collagen‐induced arthritis treated with cilostazol (10 and 30 mg/kg/day), paw thickness was decreased with increased apoptotic cells in the joints. In synovial cells transfected with small interfering RNA (siRNA) targeting HO‐1, cilostazol did not suppress expression of TNFα, IL‐1β, and IL‐6, in contrast to findings with negative control cells. Cilostazol‐ and CoPP‐induced HO‐1 expression was diminished in cells transfected with Nrf2 siRNA. Conclusion Cilostazol suppressed proliferation of synovial cells from RA patients by enhancing apoptosis, and also inhibited cytokine production via mediation of cAMP‐dependent protein kinase activation–coupled Nrf2‐linked HO‐1 expression.