[Effect of miR-204-5p on the proliferation, migration, and invasion on tongue squamous cell carcinoma SCC25 cells by targeting bromodomain-containing protein 4]

MiR-204-5p Alleviates Neuropathic Pain by Targeting BRD4 in a Rat Chronic Constrictive Injury Model

Purpose

The pathogenesis of neuropathic pain is complex, and previous studies have found that microRNAs are important regulators of neuropathic pain and are associated with the progression of neuropathic pain. This study aims to explore the level and role of miR-204-5p in the chronic constrictive injury (CCI) model of rats.

Patients and Methods

The CCI rat model was constructed to evaluate paw withdrawal threshold (PWT), paw withdrawal latency (PWL), the expressions of miR-204-5p, and the contents of inflammatory factors in the model. Overexpression of miR-204-5p in rat spinal cord was induced by intrathecal injection of miR-204-5p mimics. PWT and PWL were used to estimate mechanical and thermal pain thresholds. IL-6 and TNF-α were determined by ELISA. Luciferase reporter gene was conducted to verify the targeting relationship between miR-204-5p and BRD4.

Results

miR-204-5p was abnormally down-regulated in the CCI group. The thresholds of mechanical and thermal pain stimulation in the CCI group were lower, and the levels of inflammatory factors were higher than those in the sham group. Overexpression of miR-204-5p alleviated PWT, PWL and inflammatory factors. Besides, the luciferase reporter gene showed that BRD4 was a target gene of miR-204-5p.

Conclusion

These results suggested that miR-204-5p may alleviate neuropathic pain and inflammation through targeted regulation of BRD4 expression.

Remote ischemic preconditioning protects against cerebral ischemia injury in rats by upregulating miR-204-5p and activating the PINK1/Parkin signaling pathway

Remote ischemic preconditioning (RiPC) is the process where preconditioning ischemia protects the organs against the subsequent index ischemia. RiPC is a protective method for brain damage. This study is to explore the effect and mechanism of RiPC in cerebral ischemia injury in rats through regulation of miR-204-5p/BRD4 expression. Middle cerebral artery occlusion (MCAO) rat model and glucose deprivation (OGD) neuron model were established. The effect of RiPC on neurological deficits, cerebral infarct size, autophagy marker, inflammatory cytokines and apoptosis was evaluated. miR-204-5p expression was analyzed using RT-qPCR, and then downregulated using miR-204-5p antagomir to estimate its effect on MCAO rats. The downstream mechanism of miR-204-5p was explored. RiPC promoted autophagy, reduced cerebral infarct volume and neurological deficit score, and alleviated apoptosis and cerebral ischemia injury in rats, with no significant effects on healthy rat brains. RiPC up-regulated miR-204-5p expression in MCAO rats. miR-204-5p knockdown partially reversed the effect of RiPC. RiPC promoted autophagy in OGD cells, and attenuated inflammation and apoptosis. miR-204-5p targeted BRD4, which partially reversed the effect of miR-204-5p on OGD cells. RiPC activated the PINK1/Parkin pathway via the miR-204-5p/BRD4 axis. In conclusion, RiPC activated the PINK1/Parkin pathway and prevented cerebral ischemia injury by up-regulating miR-204-5p and inhibiting BRD4.