Interleukin-10 modulates pro-apoptotic effects of TNF-alpha in human articular chondrocytes in vitro.
The aim of this study is to determine if there is an antagonistic effect between tumour necrosis factor (TNF)-alpha and the immunoregulatory interleukin (IL)-10 on chondrocytes survival. Serum-starved primary human articular chondrocytes were stimulated with either 10 ng/ml recombinant TNF-alpha, IL-10 or a combination of both (at 10 ng/ml each). Chondrocyte apoptosis was determined by measuring caspase-3/7, -8 and -9 activities using caspase assays. Mitochondrial apoptotic inducer bax, and the suppressor bcl-2 were evaluated using western blotting at 48 h. Results indicated that TNF-alpha increased caspase activities and resulted in a significant (p = 0.001) increase in bax/bcl-2 ratio. Stimulation with IL-10 did not alter caspase activities, while co-treatment with IL-10 and TNF-alpha inhibited TNF-alpha induced caspase activities and significantly (p > 0.004) impaired bax/bcl-2 ratio. At 24 h, mRNA levels for collagen type II, TNF-alpha and IL-10 were determined using real-time RT-PCR. Stimulation with TNF-alpha or TNF-alpha and IL-10 significantly inhibited collagen type II and increased IL-10 and TNF-alpha mRNA expression. IL-10 modulated the pro-apoptotic capacity of TNF-alpha in chondrocytes as shown by the decrease in caspase activities and bax/bcl-2 ratio compared to TNF-alpha stimulated chondrocytes, suggesting a mostly antagonistic interplay of IL-10 and TNF-alpha on mitochondrial apoptotic pathways.
John
T
T
Department for Trauma and Reconstructive Surgery, Charité-University of Medicine, Campus Benjamin Franklin, FEM, Krahmerstrasse 6-10, 12207 Berlin, Germany.
Müller
R D
RD
Oberholzer
A
A
Zreiqat
H
H
Kohl
B
B
Ertel
W
W
Hostmann
A
A
Tschoeke
S K
SK
Schulze-Tanzil
G
G
D000368:Aged; D017209:Apoptosis / Q000187:drug effects* / Q000276:immunology; D002358:Cartilage, Articular / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D020169:Caspases / Q000276:immunology / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D024043:Collagen Type II / Q000096:biosynthesis / Q000276:immunology; D004336:Drug Antagonism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology; D006801:Humans; D016753:Interleukin-10 / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000276:immunology / Q000494:pharmacology*; D051028:bcl-2-Associated X Protein / Q000276:immunology / Q000378:metabolism
C494826:BAX protein, human; D024043:Collagen Type II; C508609:IL10 protein, human; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D051028:bcl-2-Associated X Protein; D016753:Interleukin-10; D020169:Caspases