Silencing long noncoding RNA colon cancer-associated transcript-1 upregulates microRNA-34a-5p to promote proliferation and differentiation of osteoblasts in osteoporosis

Long noncoding RNAs (lncRNAs) have been revealed to be related to multiple physiological and pathology processes such as development, carcinogenesis, and osteogenesis. It is reported that lncRNAs might exert function in osteoblast differentiation and bone formation. Here, we determined this study to clarify whether lncRNA CCAT1 could regulate osteoblast proliferation and differentiation in ovariectomized rats with osteoporosis. The osteoporosis models were established by bilateral ovariectomy and treated with CCAT1 siRNAs to discuss the effect of CCAT1 on pathological changes and osteocyte apoptosis in ovariectomized rats with osteoporosis. The osteoblasts from ovariectomized rats were cultured in vitro, which were then treated with CCAT1 siRNAs to explore the role of CCAT1 in osteoblast proliferation and differentiation. Moreover, the relationships among CCAT1, miR-34a-5p, and SMURF2 were confirmed. CCAT1 and SMURF2 were amplified while miR-34a-5p expression was inhibited in bone tissues and osteoblasts of ovariectomized rats with osteoporosis. Inhibited CCAT1 improved pathology and restricted osteocyte apoptosis of bone tissues in ovariectomized rats with osteoporosis in vivo, and also enhanced differentiation, mineralization abilities, and proliferation, and suppressed apoptosis of osteoblasts from ovariectomized rats in vitro through upregulating miR-34a-5p expression. LncRNA CCAT1 could competitively bind with miR-34a-5p to prevent the degradation of its target gene SMURF2. Results of this research suggested that the CCAT1 inhibits the proliferation and differentiation of osteoblasts in rats with osteoporosis by binding to miR-34a-5p, providing novel biomarkers for osteoporosis treatment.