Long non-coding RNA Snhg3 protects against hypoxia/ischemia-induced neonatal brain injury.

Hypoxic-ischemic brain damage (HIBD) is a major cause of morbidity and mortality in the preterm and term infant. However, the precise mechanism of HIBD remains largely elusive. As a newly discovered long non-coding RNA, small nucleolar RNA host gene 3 (Snhg3) has shown its important roles in cell apoptosis, proliferation, and disease development. In this study, we determined the role of Snhg3 in the pathogenesis of HIBD. Snhg3 expression was significantly down-regulated in the neonatal brain and primary hippocampal cells response to hypoxic/ischemic stress. Snhg3 overexpression protected against hypoxic/ischemic-induced brain injury in vivo and hippocampal cell injury in vitro. Snhg3 acted as the sponge of miR-196 in the hippocampal cells by regulating the expression of miR-196 target genes, XIAP and CAAP1. Moreover, Snhg3 overexpression decreased brain infarct size and ameliorated hypoxic-ischemic neonatal brain damage. This study suggests that Snhg3 is a potential target for the treatment of HIBD.

GAS5 silencing protects against hypoxia/ischemia-induced neonatal brain injury.

Hypoxic/ischemic brain damage (HIBD) leads to high neonatal mortality and severe neurologic morbidity. However, the molecular mechanism of HIBD in the neonatal infant is still elusive. Long non-coding RNAs are shown as important regulators of brain development and many neurological diseases. Here, we determined the role of long noncoding RNA-GAS5 in HIBD. GAS5 expression was significantly up-regulated in hypoxic/ischemic-injured neonatal brain and hippocampal neurons. GAS5 silencing protected against hypoxic/ischemic-induced brain injury in vivo and primary hippocampal neuron injury in vitro. Mechanistically, GAS5 regulated hippocampal neuron function by sponging miR-23a. Intracerebroventricular injection of GAS5 shRNA significantly decreased brain GAS5 expression, reduced brain infarct size, and improved neurological function recovery. Collectively, this study suggests a promising therapeutic approach of GAS5 inhibition in the treatment of neonatal HIBD.

Silencing of long non­coding antisense RNA brain­derived neurotrophic factor attenuates hypoxia/ischemia­induced neonatal brain injury.

Hypoxic/ischemic (HI) brain damage (HIBD) is a major cause of acute neonatal brain injury, leading to high mortality and serious neurological deficits. The antisense RNA of brain­derived neurotrophic factor (BDNF­AS) is transcribed from the opposite strand of the BDNF gene. The aim of the present study was to investigate the role of BDNF­AS in HI­induced neuronal cell injury in vivo and in vitro. Reverse transcription­quantitative PCR (RT­qPCR) assays indicated that BDNF­AS expression was significantly upregulated in HI­injured neonatal brains and hippocampal neurons. However, BDNF expression was downregulated in HI­injured neonatal brains and hippocampal neurons. Cell Counting Kit­8 assays, Hoechst staining, calcein­AM/PI staining, immunostaining, water maze tests and rotarod tests demonstrated that BDNF­AS silencing protected against hypoxia­induced primary hippocampal neuron injury in vitro and HI­induced brain injury in vivo. Mechanistically, RT­qPCR assays and western blotting indicated that BDNF­AS silencing led to increased expression of BDNF and activated the BDNF­mediated signaling pathway, as demonstrated by increased expression levels of BDNF, phosphorylated­Akt and phosphorylated­tropomyosin receptor kinase B. Collectively, the present study provides important insights into the pathogenesis of HIBD, and it was indicated that BDNF­AS silencing may be a promising approach for the treatment of neonatal HIBD.

High-throughput sequencing analysis of lncRNAs in hippocampus tissues with hypoxic-ischemic brain damage.

LncRNAs abundantly expressed in the brain have vital and wide-ranging functions in different biological processes. However, little is currently known regarding the influence of lncRNAs in developing brains after hypoxic-ischemic brain damage (HIBD). In this study, to investigate the lncRNAs expression signatures and the co-expression network of lncRNAs and mRNAs in the brain after HIBD, we established a neonatal rat HIBD model and detected the expression profiles of lncRNAs in the HIBD brain and a sham control using high-throughput sequencing. Further, highly differentially expressed lncRNAs were selected and validated by qRT-PCR. Finally, the biological functions of the selected lncRNAs were investigated by over-expressing or silencing the target genes through lentivirus transfection in hippocampal neuron cells. Our results revealed that the expression profile of lncRNAs was dramatically different between the HIBD brains and the sham control, showing as the aberrant expression of 617 lncRNA transcripts and 441 mRNA transcripts at 24 hours after HIBD. GO and KEGG analyses indicated that the differentially expressed mRNAs were mostly involved in the apoptosis signaling pathway. After validating the expression of 8 randomly selected lncRNA transcripts by qRT-PCR, we found that the TNFRSF17 gene (ID: ENSRNOG00000021987) was down-regulated in HI brains. After stable over-expression and silencing of TNFRSF17, the apoptosis rate of hippocampal neuron cells exhibited obvious changes under hypoxia or normaxia. The over-expression of TNFRSF17 could significantly up-regulate Bcl-2 but down-regulate Bax, caspase-3, and caspase-9 at the mRNA and protein levels, while the silencing of TNFRSF17 led to just the opposite phenomenon. Notably, the regulation effects of TNFRSF17 on apoptotic related genes and proteins under hypoxia were more obvious than those under normaxia. Moreover, the over-expression of TNFRSF17 reduced the apoptotic rate, but the loss of TNFRSF17 led to a high rate of apoptosis under hypoxia. Taken together, the silencing of TNFRSF17 exacerbated, while over-expression attenuated, neuron apoptosis induced by HI injury, suggesting that TNFRSF17 may be a target for the prognosis, diagnosis, and treatment of HIBD.