Over-expression of carbonic anhydrase 1 is involved in bio-mineralization process / 中华风湿病学杂志

ABSTRACT

Objective Carbonic anhydrase 1 (CA1) not only enhances the hydration reaction but also promotes the formation of CaCO3,which is an essential step for new bone formation in vitro.However,there is no direct evidence to demonstrate the involvement of CA1 in bio-mineralization in cells and tissues.This study is aimed to evaluate the important role of CA1 in bio-mineralization and ossification in cultured cells.Methods Calcification in Saos-2 cells was induced using osteogenic medium (OM) and the calcification was determined by Alizarin Red-S staining.The expressions of ossification protein marker Runt-related transcription factor-2 (Runx2),osterix (OSX),alkaline phosphatase (ALP),osteocalcin (OCN) and bone sialoprotein (BSP) were detected in the process of bone formation by real-time PCR.The expression of CA 1 in the calcified cells were measured using real-time PCR and Western blotting.We also detected calcification in Saos-2 cells in the presence of acetazolamide,an anti-carbonic anhydrase drug to CA1,to determine the role of CA1 in biomineralization in culture cells.T test analysis was used to compare the two groups,M-ANOVA of repeated measurs was conducted for different time point.Results Following the stimulation of OM,Saos-2 cells produced a great amount of calcium-rich deposits [0.68±0.03 vs 2.76±0.13,P＜0.01].Increased transcriptions of ossification protein markers were also detected in these stimulated Saos-2 cells,indicating that the OM launched the process of bone formation in the cells.CA1 had a significantly increased expression during this process [0.25±0.03 vs 0.94±0.06,P＜0.01].Following treatment with acetazolamide,the expression of CA1 evidently declined [1.09±0.05 vs 0.55±0.07,P＜0.05],and the mineralized nodule formation was declined [2.76±0.13 vs 2.19±0.07,P＜0.01].Conclusion These findings indicate that CA1 participates in the biomineralization and ossification,and may play an important roles in bone formation.