Role of miR-326 in neonatal hypoxic-ischemic brain damage pathogenesis through targeting of the \u03b4-opioid receptor

Xuan Wang,Jie Qiu,Xiaoguang Zhou,Rui Cheng,Xuewen Hou,Jun Chen,Han Zhou

doi:10.1186/s13041-020-00579-4

Abstract

Hypoxic-ischemic brain damage (HIBD) is a relatively common malignant complication that occurs in newborn infants, but promising therapies remain limited. In this study, we focused on the role of miR-326 and its target gene δ-opioid receptor (DOR) in the pathogenesis of neonatal HIBD. The expression levels of miR-326 and DOR after hypoxic-ischemic injury were examined both in vivo and in vitro. The direct relationship between miR-326 and DOR was confirmed by a dual-luciferase reporter assay. Further, effects of miR-326 on cell viability and apoptosis levels under oxygen glucose deprivation (OGD) were analyzed. The expression levels of miR-326 were significantly lower and DOR levels were significantly higher in the HIBD group than the control group both in vivo and in vitro. Overexpression of miR-326 downregulated the expression of DOR, while suppression of miR-326 upregulated the expression of DOR. The dual-luciferase reporter assay further confirmed that DOR could be directly targeted and regulated by miR-326. MiR-326 knockdown improved cell survival and decreased cell apoptosis by decreasing the expression levels of Caspase-3 and Bax and increasing Bcl-2 expression in PC12 cells after exposure to OGD. Moreover, DOR knockdown rescued the effect of the improved cell survival and suppressed cell apoptosis induced by silencing miR-326. Our findings indicated that inhibition of miR-326 may improve cell survival and decrease cell apoptosis in neonatal HIBD through the target gene DOR.

Highlights

Hypoxic-ischemic brain damage (HIBD), a relatively common malignant complication, occurs in 1 to 6 of every 1000 live term births and up to 40,000 to 50,000 infants each year in China and is a major cause of neonatal death and neurological dysfunction in infants and children [1, 2]
Our results showed that the expression of miR-326 in both the serum and cerebrospinal fluids (CSF) of HIBD infants was significantly lower than that in controls
There is no evidence that it has functions in neonatal HIBD [26, 27]

Summary

Introduction

Hypoxic-ischemic brain damage (HIBD), a relatively common malignant complication, occurs in 1 to 6 of every 1000 live term births and up to 40,000 to 50,000 infants each year in China and is a major cause of neonatal death and neurological dysfunction in infants and children [1, 2]. Approximately 40% of affected infants die in the neonatal period, and approximately 30% of surviving infants have long-term neurological deficits, such as epilepsy, cerebral palsy and MicroRNAs (miRNAs) are small, noncoding RNAs that negatively regulate gene expression at the posttranscriptional level. MiRNAs, including miR-128 [6], miR-210 [7,8,9,10], and miR-378 [11], participate in hypoxic-ischemic (HI) injury. MiRNAs may be novel therapeutic targets for the treatment of HIBD.

Methods

Results

Conclusion