Serum miR-885-5p as a novel diagnostic biomarker and therapeutic target in postmenopausal osteoporosis via CPEB3-mediated osteoblast dysfunction

Postmenopausal osteoporosis (PMOP) involves impaired osteoblast function, but reliable diagnostic biomarkers and therapeutic targets remain limited. This study investigated the clinical significance and functional mechanism of serum miR-885-5p in PMOP. Serum samples were collected from 98 PMOP patients and 86 non-osteoporosis postmenopausal controls (controls). The diagnostic performance of serum miR-885-5p for discriminating PMOP patients from controls was evaluated using receiver operating characteristic (ROC) analysis. Logistic regression assessed the independent contribution of miR-885-5p to PMOP pathogenesis. In vitro experiments utilized MC3T3-E1 cells for osteogenic induction, transfection (miR-885-5p mimic/inhibitor), qRT-PCR, and Transwell migration tests. Bioinformatics prediction, dual-luciferase reporting, and RNA immunoprecipitation (RIP) identified target interactions. Serum miR-885-5p expression was significantly elevated in PMOP patients versus controls. ROC analysis demonstrated high diagnostic accuracy (AUC = 0.888, sensitivity = 80.61%, specificity = 80.23%). Overexpression of miR-885-5p suppressed osteoblast differentiation, proliferation, and migration. Mechanistically, miR-885-5p directly targeted the 3'UTR of CPEB3 mRNA, repressing its expression. RIP assays confirmed enrichment of miR-885-5p and CPEB3 within the RISC complex. Crucially, CPEB3 overexpression rescued miR-885-5p-mediated inhibition of osteoblast function. These findings suggest that serum miR-885-5p may serve as a potential diagnostic biomarker for discriminating PMOP patients from non‑osteoporotic postmenopausal controls. The miR-885-5p/CPEB3 axis contributes to osteoblast dysfunction, representing a potential therapeutic target for future therapeutic exploration, although in vivo validation is required before any clinical translation.