miR-302a-3p mitigates intervertebral disc degeneration progression through regulating EPHA2.

Abstract

Intervertebral disc degeneration (IDD) underlying molecular mechanisms remain incompletely understood. To explore the role of miR-302a-3p in IDD and elucidate its targeted regulatory mechanism. 130 IDD patients and 130 healthy controls were collected. The miR-302a-3p and EPHA2 expressions were measured using reverse transcription quantitative polymerase chain reaction (RT-qPCR). A lipopolysaccharide (LPS)-induced cell injury model was established using human nucleus pulposus (NP) cells. Proliferation was assessed using the cell counting kit-8 (CCK-8) assay, apoptosis was determined by flow cytometry, and the concentrations of inflammatory factors were measured by enzyme-linked immunosorbent assay (ELISA). A dual-luciferase reporter gene assay was conducted to confirm the targeted regulatory interaction. miR-302a-3p expression was significantly decreased in IDD patients (P < 0.001), and receiver operating characteristic (ROC) curve analysis indicated that it possessed certain diagnostic potential (P < 0.001, AUC = 0.8808, 95% confidence interval (CI) = 0.8400-0.9216). In the LPS-induced NP cell injury model, miR-302a-3p expression was down-regulated, which was accompanied by reduced cell proliferation, increased apoptosis, and elevated tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) secretion (P < 0.001). However, overexpression of miR-302a-3p could effectively alleviate these injury-related effects. Furthermore, miR-302a-3p directly targeted EPHA2, whose expression was up-regulated in IDD (P < 0.001). Overexpression of EPHA2 partially reversed the protective effects of miR-302a-3p on cell proliferation, apoptosis, and inflammatory responses (P < 0.001). miR-302a-3p significantly mitigated inflammatory responses and suppressed cell apoptosis by directly targeting and downregulating EPHA2 expression, thereby delaying the progression of IDD.