Long non-coding RNA MALAT1 sponges microRNA-429 to regulate apoptosis of hippocampal neurons in hypoxic-ischemic brain damage by regulating WNT1.

Hypoxic-ischemic brain damage (HIBD) is a common neurological disorder. Emerging reports reveal that long non-coding RNAs and microRNAs (miRs) are implicated in the progress of HIBD. In this study we tried to ascertain whether lncRNA MALAT1, with the involvement of miR-429 and WNT1, affects HIBD. Initially, a HIBD mouse model was established. Then, we treated HIBD mice with dexmedetomidine (DEX) and then up- or down-regulated the expression of MALAT1, miR-429 and WNT1 in HIBD mice and neurons. Meanwhile, brain injury and hippocampal neuronal apoptosis were evaluated. Moreover, the interaction among MALAT1, miR-429 and WNT1 in HIBD was investigated. MALAT1 and WNT1 were high-expressed in brain tissues of HIBD mice while miR-429 was low-expressed in brain tissues from HIBD mice. Interestingly, MALAT1 silencing was observed to enhance the cerebral protection of DEX against HIBD. In addition, it was confirmed that MALAT1 sponged miR-429 downregulating expression of miR-429, thereby promoting apoptosis of hippocampal neurons. This effect was achieved through up-regulating the level of WNT1. Taken together, this study demonstrates that silencing of MALAT1 enhances the cerebral protection of DEX against HIBD by suppressing WNT1 expression through miR-429.