RESUMO
The pattern of collagen cross-linking is tissue specific primarily determined by the extent of hydroxylation and oxidation of specific lysine residues in the molecule. In this study, murine pre-myoblast cell line, C2C12 cells, were transdifferentiated into osteoblastic cells by bone morphogenetic protein (BMP)-2 treatment, and the gene expression of lysyl hydroxylases (LH1, 2a/b, and 3) and lysyl oxidase (LOX)/lysyl oxidase-like proteins (LOXL1-4), and the extent of hydroxylysine were analyzed. After 24h of treatment, the expression of most isoforms were upregulated up to 96h whereas LH2a and LOXL2 decreased with time. In the treated cells, both hydroxyproline and hydroxylysine were detected at day 7 and increased at day 14. The ratio of hydroxylysine to hydroxyproline was significantly increased at day 14. The results indicate that LHs and LOX/LOXLs are differentially responsive to BMP-induced osteoblast differentiation that may eventually lead to the specific collagen cross-linking pattern seen in bone.
Assuntos
Proteínas Morfogenéticas Ósseas/metabolismo , Diferenciação Celular , Colágeno Tipo I/metabolismo , Osteoblastos/citologia , Osteoblastos/metabolismo , Processamento de Proteína Pós-Traducional , Fator de Crescimento Transformador beta/metabolismo , Animais , Proteína Morfogenética Óssea 2 , Proteínas Morfogenéticas Ósseas/genética , Linhagem Celular , Humanos , Hidroxilisina/análise , Hidroxilisina/metabolismo , Hidroxiprolina/análise , Hidroxiprolina/metabolismo , Isoenzimas/genética , Isoenzimas/metabolismo , Camundongos , Mioblastos/citologia , Mioblastos/metabolismo , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/classificação , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/genética , Pró-Colágeno-Lisina 2-Oxoglutarato 5-Dioxigenase/metabolismo , Proteína-Lisina 6-Oxidase/classificação , Proteína-Lisina 6-Oxidase/genética , Proteína-Lisina 6-Oxidase/metabolismo , Splicing de RNA/genética , RNA Mensageiro/genética , Fator de Crescimento Transformador beta/genéticaRESUMO
We report on the isolation and characterization of cDNA clones for mouse lysyl hydroxylases 1, 2 and 3 (LH1, LH2, LH3). Phylogenetic analysis using nine lysyl hydroxylase sequences from five species indicates that the isoforms are derived from an ancestral gene by two duplication events, isoforms 1 and 2 being more closely related and having resulted from a more recent duplication than isoform 3. Expression of the isoforms is highly regulated in adult mouse tissues. LH1 is strongly expressed in the liver, heart, lung, skeletal muscle and kidney tissue, LH2 expression is high in the heart, lung, kidney, eye, ovary and placenta, whereas LH3 expression is high in the heart, lung, liver and testis tissue.
