Diabetic osteopenia by decreased β-catenin signaling is partly induced by epigenetic derepression of sFRP-4 gene.

In diabetics, methylglyoxal (MG), a glucose-derived metabolite, plays a noxious role by inducing oxidative stress, which causes and exacerbates a series of complications including low-turnover osteoporosis. In the present study, while MG treatment of mouse bone marrow stroma-derived ST2 cells rapidl...

Descripción completa

Guardado en:
Detalles Bibliográficos
Autores principales: Kiyoshi Mori, Riko Kitazawa, Takeshi Kondo, Michiko Mori, Yasuhiro Hamada, Michiru Nishida, Yasuhiro Minami, Ryuma Haraguchi, Yutaka Takahashi, Sohei Kitazawa
Formato: article
Lenguaje:EN
Publicado: Public Library of Science (PLoS) 2014
Materias:
R
Q
Acceso en línea:https://doaj.org/article/a9bfbcff677140e7a88001f5703c99f3
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
Descripción
Sumario:In diabetics, methylglyoxal (MG), a glucose-derived metabolite, plays a noxious role by inducing oxidative stress, which causes and exacerbates a series of complications including low-turnover osteoporosis. In the present study, while MG treatment of mouse bone marrow stroma-derived ST2 cells rapidly suppressed the expression of osteotrophic Wnt-targeted genes, including that of osteoprotegerin (OPG, a decoy receptor of the receptor activator of NF-kappaB ligand (RANKL)), it significantly enhanced that of secreted Frizzled-related protein 4 (sFRP-4, a soluble inhibitor of Wnts). On the assumption that upregulated sFRP-4 is a trigger that downregulates Wnt-related genes, we sought out the molecular mechanism whereby oxidative stress enhanced the sFRP-4 gene. Sodium bisulfite sequencing revealed that the sFRP-4 gene was highly methylated around the sFRP-4 gene basic promoter region, but was not altered by MG treatment. Electrophoretic gel motility shift assay showed that two continuous CpG loci located five bases upstream of the TATA-box were, when methylated, a target of methyl CpG binding protein 2 (MeCP2) that was sequestered upon induction of 8-hydroxy-2-deoxyguanosine, a biomarker of oxidative damage to DNA. These in vitro data suggest that MG-derived oxidative stress (not CpG demethylation) epigenetically and rapidly derepress sFRP-4 gene expression. We speculate that under persistent oxidative stress, as in diabetes and during aging, osteopenia and ultimately low-turnover osteoporosis become evident partly due to osteoblastic inactivation by suppressed Wnt signaling of mainly canonical pathways through the derepression of sFRP-4 gene expression.