microRNA-126 inhibits tube formation of HUVECs by interacting with EGFL7 and down-regulating PI3K/AKT signaling pathway.

It's critical for tube formation and angiogenesis to repair ischemic myocardium or stroke. This study aimed to investigate role of microRNA-126 (miR-126) in tube formation in human umbilical vein endothelial cells (HUVECs) and associated mechanisms. Primary neural stem cells (NSCs) and HUVECs were cultured and transfected with microRNA-126 mimics and miR-126 inhibitor. Cell counting kit-8 (CCK-8) and cell cycle assay were conducted for evaluating NSCs viability. Transwell assay was conducted to observe invasive ability of HUVECs. Quantitative real-time PCR (qRT-PCR) assay was used to examine epidermal growth factor like domain 7 (EGFL7) and miR-126 mRNA both in vitro and animal models. Tube forming capability was evaluated in HUVECs. Dual luciferase assay was performed to evaluate interaction between miR-126 and EGFL7 gene. Western blot assay was used to determine phosphoinositide-3-kinase/protein kinase-B (PI3K/AKT) signaling molecules and EGFL7. The results indicated that miR-126 significantly decreased cell viability, inhibited invasive ability and modulated cell cycle of NSCs compared to miR-NC group (p < 0.05). miR-126 significantly inhibited tube formation of HUVECs compared to miR-NC group (p < 0.05). miR-126 significantly down-regulated EGFL7 mRNA and protein expression compared to miR-NC (p < 0.05). Atorvastatin significantly increased CD34 and enhanced EGFL7 expression in traumatic brain injury (TBI) rats brain tissues compared to Model group (p < 0.05). miR-126 significantly down-regulated and atorvastatin up-regulated PI3K/AKT signaling pathway (p < 0.05). Atorvastatin significantly increased EGFL7 and down-regulated miR-126 expression in TBI rats brain tissues compared to Model group (p < 0.05). miR-126 interacted with and negatively correlated with EGFL7 gene both in vitro and in TBI models. In conclusion, microRNA-126 inhibited tube formation of HUVECs by interacting with EGFL7 and down-regulating PI3K/AKT signaling pathway.

Suppression of STIM1 in the early stage after global ischemia attenuates the injury of delayed neuronal death by inhibiting store-operated calcium entry-induced apoptosis in rats.

Ca²âº overload is considered to be the most important ion imbalance in the neuronal injury. Store-operated Ca²âº entry has been suggested to be a significant mechanism of excessive Ca²âº influx in many cells. The role of store-operated Ca²âº entry in neuronal ischemic injury has yet to be elucidated. The aim of this study was to assess the role of store-operated calcium channel (SOCC) proteins involved with calcium overload in the induction of delayed neuronal death after global ischemia in rats. A transient RNA interference model of global ischemia in rats was established to determine the role of SOCC-induced Ca²âº overload in delayed neuronal death. We found that STIM1 and ORAI1 expression in the hippocampus increased continuously after global ischemia and peaked on day 4. These data were consistent with an increase in the intracellular calcium concentration. Using Stim1 siRNA to suppress SOCC activity in the early stage of ischemia significantly inhibited STIM1 and ORAI1 expression and decreased the intracellular calcium concentration in neurons. In addition, the neurological function of rats improved after the Stim1 siRNA injection. High expression of STIM1 and ORAI may be the source of excessive calcium influx after ischemic damage. Blocking of this SOCC-induced calcium influx could lead to an improved neuronal survival. These data suggest that calcium influx through SOCC is another nonexcitotoxicity mechanism of ischemic neuronal death.