Down‐regulation of myeloid cell leukemia 1 by epigallocatechin‐3‐gallate sensitizes rheumatoid arthritis synovial fibroblasts to tumor necrosis factor α–induced apoptosis

Wiley - Tập 60 Số 5 - Trang 1282-1293 - 2009
Salahuddin Ahmed1, Matthew D. Silverman1, Hubert Marotte1, K.H. Kwan1, Natalie Matuszczak1, Alisa E. Koch2
1University of Michigan Medical School, Ann Arbor
2University of Michigan Medical School, Ann Arbor, and Veterans Affairs Medical Center, Ann Arbor, Michigan

Tóm tắt

AbstractObjectiveOverexpression of the antiapoptotic protein myeloid cell leukemia 1 (Mcl‐1) in rheumatoid arthritis (RA) synovial fibroblasts is a major cause of their resistance to tumor necrosis factor α (TNFα)–induced apoptosis. This study was undertaken to evaluate the efficacy of epigallocatechin‐3‐gallate (EGCG) in down‐regulating Mcl‐1 expression and its mechanism of RA synovial fibroblast sensitization to TNFα‐induced apoptosis.MethodsEGCG effects on cultured RA synovial fibroblast cell morphology, proliferation, and viability over 72 hours were determined by microscopy and a fluorescent cell enumeration assay. Caspase 3 activity was determined by a colorimetric assay. Western blotting was used to evaluate the apoptosis mediators poly(ADP‐ribose) polymerase (PARP), Mcl‐1, Bcl‐2, Akt, and nuclear translocation of NF‐κB.ResultsIn RA synovial fibroblasts, EGCG (5–50 μM) inhibited constitutive and TNFα‐induced Mcl‐1 protein expression in a concentration‐ and time‐dependent manner (P < 0.05). Importantly, EGCG specifically abrogated Mcl‐1 expression in RA synovial fibroblasts and affected Mcl‐1 expression to a lesser extent in osteoarthritis and normal synovial fibroblasts or endothelial cells. Inhibition of Mcl‐1 by EGCG triggered caspase 3 activity in RA synovial fibroblasts, which was mediated via down‐regulation of the TNFα‐induced Akt and NF‐κB pathways. Caspase 3 activation by EGCG also suppressed RA synovial fibroblast growth, and this effect was mimicked by Akt and NF‐κB inhibitors. Interestingly, Mcl‐1 degradation by EGCG sensitized RA synovial fibroblasts to TNFα‐induced PARP cleavage and apoptotic cell death.ConclusionOur findings indicate that EGCG itself induces apoptosis and further sensitizes RA synovial fibroblasts to TNFα‐induced apoptosis by specifically blocking Mcl‐1 expression and, hence, may be of promising adjunct therapeutic value in regulating the invasive growth of synovial fibroblasts in RA.

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Tài liệu tham khảo

10.1126/science.7878464

10.1158/0008-5472.CAN-07-0082

10.1016/j.ccr.2006.03.027

10.1093/rheumatology/kel065

10.2174/1381612053381945

10.1016/j.rdc.2004.04.010

10.4049/jimmunol.175.12.8337

10.1016/S1471-4892(03)00037-7

10.1002/1529-0131(200005)43:5<1094::AID-ANR20>3.0.CO;2-V

10.1002/1529-0131(200107)44:7<1555::AID-ART279>3.0.CO;2-M

10.1038/nri846

10.1158/0008-5472.CAN-05-3636

10.1016/j.taap.2006.03.013

10.1038/sj.onc.1210840

10.1158/0008-5472.CAN-07-1691

10.1002/art.22023

10.1002/art.1780310302

10.1074/jbc.M414469200

10.1002/art.20680

10.1126/science.281.5381.1322

10.4049/jimmunol.164.10.5227

10.1074/jbc.M412819200

10.1101/gad.1093903

10.1016/j.biocel.2004.04.007

10.1038/sj.leu.2403667

10.1016/j.ccr.2006.08.027

10.1172/JCI9053

10.1023/A:1016119328968

10.1074/jbc.273.16.9357

10.1038/sj.cdd.4400476

10.1016/j.mrfmmm.2005.04.010

10.1016/S0002-9440(10)64272-1

10.2174/1381612053381918

10.1002/art.20468

10.1186/ar564

10.1002/1529-0131(200011)43:11<2391::AID-ANR3>3.0.CO;2-F

10.1124/jpet.103.059220

10.1073/pnas.0802675105

10.1177/147323000303100205

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Wiley

Tập 60 Số 5

1282-1293

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