Response of Collagen XII Splice Variants in Human Osteoblast-like Cells to IL-1β

抄録

Collagen XII, a fibril-associated collagen (FACIT), is characterized by a short triple-helical domain with three extended noncollagenous NC3 domains, and may contribute to the stability of collagen I fibrils. Differential splicing within the NC3 domain results in large and small variants of collagen XII. Little is known about the role of this FACIT collagen in bone metabolism. In this study, we demonstrated the gene expression of collagen XII splice variants in human osteoblast-like cells, and their responses to IL-1β as a bone resorptive agent.
Western blot analysis also showed the protein expression of both long- and short-form splice variants, α1(XIIA) and α1(XIIB) respectively, in osteoblast-like cells. When cells were cultured for 48 h with IL-1β, mRNA expression levels of collagen I, osteocalcin and whole collagen XII decreased compared with controls (p<0.01). Interestingly, after IL-1β stimulation, the level of α1(XII) chain decreased with time, although α1(XIIA) increased significantly by 2 h, and then decreased to a lower level compared with non-stimulated controls.
Our results clarify that the collagen XII gene is transcribed in human osteoblast-like cells, and indicate that the transcription of splice variants may be influenced by the bone resorptive agent.