Long non-coding RNA TUG1 knockdown prevents neurons from death to alleviate acute spinal cord injury via the microRNA-338/BIK axis

Taurine up-regulated gene 1 (TUG1) is a cancer-associated long noncoding RNA (lncRNA) and engages in the development of spinal cord injury (SCI), a suffering neuropathological disorder. However, the regulatory role of TUG1 in acute SCI (ASCI) is still underdetermined. RT-qPCR and western blot analysis were applied to measure the expression of TUG1, microRNA-338 (miR-338), Bcl2-interacting killer (BIK), cleaved caspase 3 (c-caspase 3) and hypoxia-inducible factor-1 alpha (HIF-1α) in ASCI rats and hypoxic cells. Cell death was evaluated using flow cytometric analysis. The relationships among miR-338, TUG1 or BIK were confirmed by luciferase reporter assay, RNA immunoprecipitation and RNA pull-down. Accordingly, we monitored higher expression of TUG1 and BIK, but lower expression of miR-338 in ASCI rats and hypoxic cells. In vitro, hypoxia expedited cell death and c-caspase 3 levels. In vivo, ASCI rats were successfully developed as evidenced by diminished Basso-Beattie-Bresnahan (BBB) locomotor score and enhanced c-caspase 3 and HIF-1α expression. Nevertheless, TUG1 knockdown mitigated the cell death in ASCI rats and hypoxic cells. Mechanically, TUG1 interacted with miR-338 to regulate the BIK expression. Together, TUG1 silencing could alleviate the death in neurons and ASCI models via modulating the miR-338/BIK axis.