Validation of downregulated microRNAs during osteoclast formation and osteoporosis progression

Abstract

Enhanced osteoclast formation and function have essential roles during post‑menopausal osteoporosis. A number of cytokines have been reported to regulate osteoclastogenesis and to be involved during the pathogenesis of osteoporosis. However, the regulation of osteolysis by microRNAs (miRNAs) has remained to be fully elucidated. The present study used a microarray analysis to identify a variety of miRNAs that are differentially expressed during osteoclast formation. Six down‑regulated miRNAs, miR‑21a‑5p, miR‑27a‑3p, let‑7i‑5p, miR‑22‑3p, miR‑340‑5p and miR‑23a‑5p, whose molecular mechanisms during osteoclast differentiation have not been reported previously, were further assessed. Using an osteoclast formation assay and a mouse model of progressive osteoporosis, the downregulation of these miRNAs was validated in vitro and in vivo. Of note, the expression patterns of these six miRNAs were associated with the progression of osteoporosis. Therefore, these miRNAs are of potential diagnostic and therapeutic value for osteolytic diseases.

miRNA-340 inhibits osteoclast differentiation via repression of MITF

“…Despite increasing researches for miRNAs in regulating bone remodeling, the precise role of miR-340 in osteoclastogenesis remains further investigation. Ma et al [13] has reported that miR-340 could regulate RAS/RAF/mitogen-activated protein kinase (MAPK) signaling, the activation of which is crucial in osteoclastogenesis, thereby is likely to exhibit potential roles in osteoclasts [32]. Our present study demonstrated that miR-340 can be significantly decreased during osteoclast differentiation under the stimulation of M-CSF and RANKL.…”

“…qRT-PCR was performed to amplify the cDNA templates by SYBR Premix Ex TaqTM II Kit (TaKaRa). The specific primer sequences for miR-340, MITF, TRAP, calcitonin receptor, V-ATPase d2, and cathepsin K were introduced as previously published [13,19–21]. The relative mRNA expression levels were calculated by the 2 −ΔΔ C t method and normalized to GAPDH.…”

“…MiRNA-340 (miR-340), a specific miRNA, is implicated in diverse cancers including gastric [9], ovarian [10], breast [11], colorectal cancer [12], and others. Besides, Ma et al [13] has presented evidence that miR-340 was down-regulated during osteoclast differentiation using microarray analysis, which was associated with the progression of osteoporosis. However, little literature concerning the precise role of miR-340 implicated in osteoclastogenesis has been published.…”

MicroRNA‑148a inhibition protects against ovariectomy‑induced osteoporosis through PI3K/AKT signaling by estrogen receptor α

“…It has been estimated that ~50% human genes are regulated by miRNAs. This is currently verified by using bioinformatics and experiments where one miRNA may specifically bind to multiple genes (18). Additionally, one gene may also be regulated by multiple miRNAs, thus exerting the regulatory function (19).…”

“…Thousands of miRNAs have been previously discovered in various organisms with increasingly intensive research on miRNA (12). miRNAs regulate various activities in organisms, such as growth, development and aging (18). It has been estimated that ~50% human genes are regulated by miRNAs.…”