Molecular Mechanism of miR-146a in Regulating the Progression of Spinal Tuberculosis via the TGF-β1/SMAD Pathway
Objective To explore the regulatory mechanism of miR-146a/transforming growth factor-β1(TGF-β1)/small mother against decapentaplegic(SMAD)signaling pathway in the progression of spinal tuberculosis.Methods The spinal tuberculosis nucleus pulposus tissues were collected and the expression of miR-146a/TGF-β1/SMAD signaling pathway in tuberculosis nucleus pulposus tissues was examined.The nucleus pulposus cells were isolated from tuberculosis nucleus pulposus tissues.Then miR-146a mimics and inhibitors were used to overexpress or knock down miR-146a.The effect of miR-146a on TGF-β1/SMAD signaling pathway was examined using qPCR and Western blotting assays.The effect of miR-146a on the proliferation and migration ability of nucleus pulposus cells were tested using CCK-8 and scratch assays.Results The proliferation and migration ability of nucleus pulposus cells in patients with lumbar tuberculosis was significantly reduced,and the expression level of miR-146a in the nucleus pulposus tissue of patients with lumbar tuberculosis patients was also significantly reduced.We also found that the expression of SMAD homologue 2(SMAD2),SMAD3,SMAD4,and TGF-β significantly increased,and the expression of SMAD7 was reduced,indicating that the expression of miR-146a was negatively correlated to the activity of TGF-β/SMAD pathway.Furthermore,overexpression of miR-146a significantly suppressed the expression of SMAD2,SMAD3,SMAD4,TGF-β1,but suppressed the expression of SMAD7.On the contrary,knocking down miR-146a significantly promoted the expression of SMAD2,SMAD3,SMAD4,TGF-β1,but inhibited the expression of SMAD7.We also found that overexpression of miR-146a could promote the proliferation and migration ability of tuberculosis nucleus pulposus cells,but knocking down miR-146a could significantly suppress the proliferation and migration ability of tuberculosis nucleus pulposus cells.Conclusion miR-146a is one of the key regulators of spinal tuberculosis progression,which regulates the proliferation and migration activity of nucleus pulposus cells by inhibiting the TGF-β1/SMAD pathway activity.
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