Mm9_circ_009056 enhances osteogenesis by targeting BMP7 via CGRP-mediated miR-22-3p.

Circular RNAs (circRNAs) are noncoding RNAs that can function as miRNA sponges, post-transcriptionally regulating the expression of genes. Here, we report a novel positive function of mm9_circ_009056 during osteogenesis in regulating bone morphogenetic protein 7 (BMP7) through miR-22-3p. First, we found that calcitonin gene-related peptide (CGRP) had great osteogenesis function on MC3T3 cells. Then aberrant expression of mm9_circ_009056 were confirmed in CGRP-induced cells. Furthermore, the expression of mm9_circ_009056 was up-regulated in the CGRP-induced cells, whereas miR-22-3p was obviously decreased. Silencing of mm9_circ_009056 increased the expression of miR-22-3p and decreased the gene and protein levels of BMP7, RUNX2. Cells proliferation and growth were also inhibited following silengcing. The protein levels of BMP7 and RUNX2 decreased after mimics transfection and increased after inhibitors transfection. In summary, mm9_circ_009056 may function as a sponge for miR-22-3p to regulate osteogenesis in CGRP-induced cells.