Affiliation:
1. Department of Biochemistry, Showa University School of Dentistry, Tokyo 142-8555, Japan
2. Department of Microbiology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto 860-8556, Japan
3. Department of Oral Anatomy and Developmental Biology, Showa University School of Dentistry, Tokyo 142-8555, Japan
Abstract
IL-1 (interleukin-1) acts as a key mediator of the degeneration of articular cartilage in RA (rheumatoid arthritis) and OA (osteoarthritis), where chondrocyte death is observed. It is still controversial, however, whether IL-1 induces chondrocyte death. In the present study, the viability of mouse chondrocyte-like ATDC5 cells was reduced by the treatment with IL-1β for 48 h or longer. IL-1β augmented the expression of the catalytic gp91 subunit of NADPH oxidase, gp91phox, as well as inducible NO synthase in ATDC5 cells. Generation of nitrated guanosine and tyrosine suggested the formation of reactive nitrogen species including ONOO− (peroxynitrite), a reaction product of NO and O2−, in ATDC5 cells and rat primary chondrocytes treated with IL-1β. Death of ATDC5 cells after IL-1β treatment was prevented by an NADPH-oxidase inhibitor, AEBSF [4-(2-aminoethyl)benzenesulphonyl fluoride], an NO synthase inhibitor, L-NAME (NG-nitro-L-arginine methyl ester), and a ONOO− scavenger, uric acid. The viability of ATDC5 cells was reduced by the ONOO−-generator 3-(4-morpholinyl)sydnonimine hydrochloride, but not by either the NO-donor 1-hydroxy-2-oxo-3-(N-methyl-2-aminopropyl)-3-methyl-1-triazene or S-nitrosoglutathione. Disruption of mitochondrial membrane potential and ATP deprivation were observed in IL-1β-treated ATDC5 cells, both of which were restored by L-NAME, AEBSF or uric acid. On the other hand, no morphological or biochemical signs indicating apoptosis were observed in these cells. These results suggest that the death of chondrocyte-like ATDC5 cells was mediated at least in part by mitochondrial dysfunction and energy depletion through ONOO− formation after IL-1β treatment.
Subject
Cell Biology,Molecular Biology,Biochemistry
Cited by
90 articles.
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