Rhizoma Drynariae-derived EV-like particles alleviate osteoporosis by promoting osteogenic differentiation in BMSCs through the activation of the hsa_circ_0001275/miR-422a pathway.

Abstract

Osteoporosis (OP) is the most prevailing primary bone disease caused by the imbalance between bone resorption and formation. Rhizoma Drynariae-derived EV-like particles (RD-EVLP) perform the anti-osteoporosis effect by promoting the osteogenic differentiation of human bone marrow mesenchymal stem cells (h-BMSCs) which may be regulated by circular RNAs (circRNAs) and microRNAs (miRNAs). This study aimed to reveal the functional roles and mechanisms of the RD-EVLP regulating osteogenic differentiation of osteoporosis through the activation of hsa_circ_0001275 sponging miR-422a. Notably, RD-EVLP isolated from fresh Rhizoma Drynariae via differential ultracentrifugation demonstrated three critical pharmacological attributes: (1) excellent biosafety profile with non-toxic and gastrointestinal stability, (2) bone-targeting specificity evidenced by femoral accumulation, and (3) potent anti-osteoporotic effects through promoting osteogenic differentiation in vivo. Meanwhile, RD-EVLP effectively internalized by h-BMSCs, enhanced proliferation of h-BMSCs, and promoted osteogenic differentiation and bone formation in vitro. For another, hsa_circ_0001275 and insulin like growth factor 1 receptor (IGF1R) expressions were upregulated while miR-422a expression was downregulated during osteogenic differentiation. Knockdown of hsa_circ_0001275 inhibited mineralized nodule formation. Moreover, miR-422a was a target of hsa_circ_0001275 and knockdown of miR-422a promoted mineralized nodule formation and greatly reinforced the expression of runt-related transcription factor 2 (RUNX2), bone morphogenetic protein 2 (BMP2), osteocalcin (OCN). What's more, miR-422a suppressed h-BMSCs osteogenic differentiation by downregulating IGF1R. Finally, RD-EVLP promoted osteogenic differentiation by enhancing hsa_circ_0001275 and IGF1R while reducing miR-422a expression levels of h-BMSCs during osteogenic induction. hsa_circ_0001275 could promote osteogenic differentiation by sponging miR-422a to upregulate IGF1R expression and RD-EVLP performed anti-OP activity through hsa_circ_0001275/miR-422a pathway.