[HTML][HTML] DNA methylation regulates sclerostin (SOST) expression in osteoarthritic chondrocytes by bone morphogenetic protein 2 (BMP-2) induced changes in Smads …
I Papathanasiou, F Kostopoulou, KN Malizos… - Arthritis research & …, 2015 - Springer
I Papathanasiou, F Kostopoulou, KN Malizos, A Tsezou
Arthritis research & therapy, 2015•SpringerIntroduction Sclerostin (SOST), a soluble antagonist of Wnt signaling, is expressed in
chondrocytes and contributes to chondrocytes' hypertrophic differentiation; however its role
in osteoarthritis (OA) pathogenesis is not well known. Based on our previous findings on the
interaction between Wnt/β-catenin pathway and BMP-2 in OA, we aimed to investigate the
role of DNA methylation and BMP-2 on SOST's expression in OA chondrocytes. Methods
SOST mRNA and protein expression levels were investigated using real-time polymerase …
chondrocytes and contributes to chondrocytes' hypertrophic differentiation; however its role
in osteoarthritis (OA) pathogenesis is not well known. Based on our previous findings on the
interaction between Wnt/β-catenin pathway and BMP-2 in OA, we aimed to investigate the
role of DNA methylation and BMP-2 on SOST's expression in OA chondrocytes. Methods
SOST mRNA and protein expression levels were investigated using real-time polymerase …
Introduction
Sclerostin (SOST), a soluble antagonist of Wnt signaling, is expressed in chondrocytes and contributes to chondrocytes’ hypertrophic differentiation; however its role in osteoarthritis (OA) pathogenesis is not well known. Based on our previous findings on the interaction between Wnt/β-catenin pathway and BMP-2 in OA, we aimed to investigate the role of DNA methylation and BMP-2 on SOST’s expression in OA chondrocytes.
Methods
SOST mRNA and protein expression levels were investigated using real-time polymerase chain reaction (PCR) and Western blot, respectively. The methylation status of SOST promoter was analysed using methylation-specific PCR (MSP), quantitative methylation-specific PCR (qMSP) and bisulfite sequencing analysis. The effect of BMP-2 and 5’-Aza-2-deoxycytidine (5-AzadC) on SOST’s expression levels were investigated and Smad1/5/8 binding to SOST promoter was assessed by Chromatin Immunoprecipitation (ChΙP).
Results
We observed that SOST’s expression was upregulated in OA chondrocytes compared to normal. Moreover, we found that the CpG region of SOST promoter was hypomethylated in OA chondrocytes and 5-AzadC treatment in normal chondrocytes resulted in decreased SOST methylation, whereas its expression was upregulated. BMP-2 treatment in 5-AzadC-treated normal chondrocytes resulted in SOST upregulation, which was mediated through Smad 1/5/8 binding on the CpG region of SOST promoter.
Conclusions
We report novel findings that DNA methylation regulates SOST’s expression in OA, by changing Smad 1/5/8 binding affinity to SOST promoter, providing evidence that changes in DNA methylation pattern could underlie changes in genes’ expression observed in OA.
Springer