Low-Level miR-199 Contribute to Neuropathic Low Back Pain via TRPV1 by Regulating the Production of Pro-Inflammatory Cytokines on Macrophage.

Aim: To explore the post-translational regulation of TRPV1, which plays an important role in neuropathic low back pain (NLBP).

Material and methods: qPCR was used to examine the gene mRNA levels. Western blot was used to examine the protein level. NLBP rat model was established for confirming what we observed in clinical samples. Dual-luciferase assay was used to verify the miR-199 targets on the 3'UTR of TRPV1. Cell coculture was used to explore the interaction between macrophages and nerve cells.

Results: We found the mRNA level of TRVP1 decreased in the sinuvertebral nerve biopsy of NLBP. With bioinformatics prediction, miR199 would involve the post-transcription regulation of TRPV1. As the prediction, the miR199 level decreased in the clinical samples. Correlation regression analysis showed a negative correlation between miR-199 and TRPV1. The same phenomenon was confirmed in the rat NLBP model. With dual-luciferase assay, we confirmed that miR199 directly binds to the 3'UTR of TRPV1. Through co-culture of macrophage (THP1) and sNF96.2, we found that up or down-regulates miR-199 in macrophage and sNF96.2 could relieve or aggravate the injury of nerve cells strain.

Conclusion: These results suggest that the occurrence of NLBP may be caused by the lower expression of miR-199 in macrophages and nerve via TRPV1.