MicroRNA-25-3p therapy for intervertebral disc degeneration by targeting the IL-1β/ZIP8/MTF1 signaling pathway with a novel thermo-responsive vector

MicroRNAs play important roles in intervertebral disc degeneration (IDD). The therapeutic effects of miRNA-25-3p on IDD and underlying mechanism are unclear.

The thermo-responsive vector delivering miRNA-25-3p could delay the progression of IDD by inhibiting IL-1β-induced effects, and may be potential therapy for IDD in future.

Normal and degenerated nuclear pulposus (NP) tissue were collected. Primary NP cells were isolated and treated with different concentrations of interleukin-1β (IL-1β). IL-1β treated NP cells were interfered with miRNA-25-3p. Associated proteins IL-1β, ZIP8, MTF1, extracellular matrix (ECM) degrading enzymes MMP3, MMP13, ADAMTS5, ECM proteins type II collagen, aggrecan and MiRNA-25-3p were detected by western blotting or qRT-PCR method. Dual luciferase reporter assays were performed to determine potential targets MTF1 of miRNA-25-3p. In vitro miRNA-25-3p transfection efficiency of thermos-responsive vector was observed by fluorescence microscopy. Animal studies were conducted to observe the therapeutic effects of miRNA-25-3p mimic delivered by thermo-responsive vector.

Compared with normal NP tissues, IL-1β, ZIP8 and MTF1 significantly increased and miRNA-25-3p significantly decreased in degenerated tissues. IL-1β promotes the expression of ZIP8 and nuclear translocation of MTF1 in NP cells. Ultimately, it promotes expression of ECM degrading enzymes and inhibits synthesis of ECM protein. MiRNA- 25-3p could inhibit the effects of IL-1β and the expression of ECM degrading enzymes, and recover the expression of ECM protein. Further investigation showed MTF1 was a target protein of miRNA-25-3p. The thermo-responsive vector could effectively deliver miRNA-25-3p into NP cells. Animal studies demonstrated miRNA-25-3p delivered by the thermo-responsive vector can delay progression of IDD. Conclusions: The thermo-responsive vector delivering miRNA-25-3p could delay the progression of IDD by inhibiting IL-1β-induced effects, and may be potential therapy for IDD in future.