The fibroblast of radicular cyst facilitate osteoclastogenesis via the autocrine of Fibronectin containing extra domain A

Objective To investigate the alternative spliced isoforms of Fibronectin (FN) in the stroma of radicular cysts and analyze the associations between these isoforms and the osteoclastogenic effects of fibroblasts. Methods and materials The specimens of radicular cysts were stained with immunohistochemistry, and the associations between each FN isoform and clinical parameters were assessed. The fibroblasts isolated from cysts or jaw bone were cultured to induce the Trap + MNCs. In the conditioned medium, the Fibronectin containing extra domain A (EDA + FN) was neutralized by antibody IST‐9, and the EDA exon of fibroblasts was knockout by CRISPR/Cas system, for assessing the osteoclastogenic effects. The mRNA level of FN isoforms and the osteoclastogenesis‐related genes were analyzed by quantitive PCR. Results EDA + FN staining was positively associated with the size of the lesions (p