Effects of HDAC6 regulation of HSC70 acetylation level on bone loss in osteoporosis after oophorectomy / 中华内分泌外科杂志

ABSTRACT

Objective:To investigate the effects of histone deacetylase 6 (histone deacetylase 6, HDAC6) on oopherectomy (OOX) induced osteoporosis (OP) bone loss by binding to the promoter region of heat-shock protein 70 (HSC70) and regulating it’s acetylation.Methods:OP mouse model was established by using OOX methods. Then the mice were divided into sham operation group, OOX group, OOX+shHDAC6 group, OOX+shNC group and OOX+shHDAC6+shHSC70 group. The micro-CT system and Western blot experiment were used to detect the bone microscopic parameters of the mouse right femur and the protein expression levels of osteoblast-specific transcription factors. In vitro experiments, Westwen blot, alkaline phosphatase (ALP) staining and Alizarin Red S (ARS) staining were used to determine the effects of HDAC6 and HSC70 on the osteogenic differentiation of MC3T3-E1 cells. QRT-PCR was used to detect the expression levels of HDAC6 and HSC70 in tissue or cells. The relationship between HDAC6 and HSC70 was analyzed by ChIP experiment.Results:Compared with sham group, the expression of bone mineral density (BMD) , trabecular bone number (Tb. N) , trabecular thickness (Tb.th) and bone volume fraction (BV/TV) in the right femur of OOX group mice were decreased, the expression of TB. Sp was increased, protein expression of OSX and RUNX2 was increased. At the same time, compared with sham group (1±0.11) , the expression of HDAC6 was increased in OOX group (2.33±0.19) ( t=10.56, P<0.001) . Compared with pcDNA3.1-NC group, the protein level of Osterix (OSX) and runt-related transcription factor 2 (RUNX2) , ALP activity and mineralized area in pcDNA3.1-HDAC6 group were decreased (all P<0.05) . ChIP analysis showed that compared with the pcDNA3.1-NC group (5.26±0.47) , the acetylation level of the HSC70 promoter region in the pcDNA3.1-HDAC6 group (2.37±0.21) was significantly reduced ( t=9.72, P<0.001) . Compared with pcDNA3.1-HDAC6 group, the expression of OSX and RUNX2, ALP activity and mineralization were increased in pcDNA3.1-HDAC6+ pcDNA3.1-HSC70 group (all P<0.05) . Compared with OOX+shHDAC6 group, the expression of OSX and RUNX2 protein, BMD, Tb.N, Tb.th and BV/TV were decreased but the expression of Tb. Sp was increased in OOX+ shHDAC6+ shHSC70 group. Conclusions:HDAC6 regulates the acetylation level of HSC70 and then affects OOX-induced OP bone loss. Inhibition of HDAC6 can significantly improve OP bone loss.