Zoledronic acid inhibits osteoclastogenesis and bone resorptive function by suppressing RANKL‑mediated NF‑κB and JNK and their downstream signalling pathways

Abstract

Targeting excessive osteoclast differentiation and activity is considered a valid therapeutic approach for osteoporosis. Zoledronic acid (Zol) plays a pivotal role in regulating bone mineral density. However, the exact molecular mechanisms responsible for the inhibitory effects of Zol on receptor activator of nuclear factor (nF)-κB ligand (ranKl)-induced osteoclast formation are not entirely clear. The present study aimed to investigate the role of Zol in osteoclast differentiation and function, and to determine whether nF-κB and mitogen-activated protein kinase, and their downstream signalling pathways, are involved in this process. raW264.7 cells were cultured with ranKl for differentiation into osteoclasts, in either the presence or absence of Zol. osteoclast formation was observed by tartrate-resistant acid phosphatase staining and bone resorption pit assays using dentine slices. The expression of osteoclast-specific molecules was analysed using reverse transcription-quantitative polymerase chain reaction and western blotting assays to deduce the molecular mechanisms underlying the role of Zol in osteoclastogenesis. The results showed that ZOL significantly attenuated osteoclastogenesis and bone resorptive capacity in vitro. Zol also suppressed the activation of nF-κB and the phosphorylation of c-Jun n-terminal kinase. Furthermore, it inhibited the expression of the downstream factors c-Jun, c-Fos and nuclear factor of activated T cells c1, thereby decreasing the expression of dendritic cell-specific transmembrane protein and other osteoclast-specific markers. in conclusion, Zol may have therapeutic potential for osteoporosis.

How zoledronic acid improves osteoporosis by acting on osteoclasts

“…ZA can inhibit the fusion of osteoclast precursors and bone resorption activity of osteoclasts by suppressing RANKL/RANK-induced osteoclast-related genes ( Cheng et al, 2021 ; Lin et al, 2021 ; Huang et al, 2022 ). It has been demonstrated experimentally that ZA can strongly inhibit the formation of tartrate-resistant acid phosphatase (TRAP)+ multinucleated osteoclasts induced by RANKL/RANK pathway ( Cheng et al, 2021 ).…”

“…It has been demonstrated experimentally that ZA can strongly inhibit the formation of tartrate-resistant acid phosphatase (TRAP)+ multinucleated osteoclasts induced by RANKL/RANK pathway ( Cheng et al, 2021 ). An experimental study treated cells with ZA after 3 days of RANKL stimulation, and found that ZA significantly inhibited the mRNA expression levels of RANK, TRAP and calcitonin receptor in cells ( Huang et al, 2022 ), then the authors further analyzed the effect of ZA on osteoclast-specific markers, the results showed that RANKL stimulation significantly induced the expression of these osteoclast-specific markers, whereas ZA treatment significantly inhibited the expression levels of these markers.…”

“…IκBα and p65 are inhibitors of NF-κB, which can suppress NF-κB signaling pathway. RANKL can induce IκBα phosphorylation, thereby promoting osteoclast differentiation and bone resorption ( Sun et al, 2020 ; Cheng et al, 2021 ; Huang et al, 2022 ). ZA can down-regulate RANKL-induced phosphorylation of IκBα and p65, simultaneously up-regulate the level of non-phosphorylated IκBα, and inhibit the nuclear translocation of p65 ( Cheng et al, 2021 ; Huang et al, 2022 ).…”

“…RANKL can induce IκBα phosphorylation, thereby promoting osteoclast differentiation and bone resorption ( Sun et al, 2020 ; Cheng et al, 2021 ; Huang et al, 2022 ). ZA can down-regulate RANKL-induced phosphorylation of IκBα and p65, simultaneously up-regulate the level of non-phosphorylated IκBα, and inhibit the nuclear translocation of p65 ( Cheng et al, 2021 ; Huang et al, 2022 ). An experimental study showed that rapid phosphorylation of IκBα and p65 was detected in RANKL-treated cells, indicating that the NF-κB pathway was activated, however, after the cells were treated with ZA, the opposite results were obtained, i.e.…”

P2X7 receptor knockdown suppresses osteoclast differentiation by inhibiting autophagy and Ca2+/calcineurin signaling

“…Macrophage colony-stimulating factor (M-CSF) and the receptor activator of NF-κB ligand (RANKL) are important factors that induce the differentiation of osteoclast precursors into mature osteoclasts ( 4 ). A previous study evaluated regulation of various genes during osteoclastogenesis ( 5 ); however, the mechanism underlying osteoclast differentiation has not been clearly elucidated.…”