Genome-wide analyses of the prognosis-related mRNA alternative splicing landscape and novel splicing factors based on large-scale low grade glioma cohort.

Alternative splicing (AS) changes are considered to be critical in predicting treatment response. Our study aimed to investigate differential splicing patterns and to elucidate the role of splicing factor (SF) as prognostic markers of low-grade glioma (LGG). We downloaded RNA-seq data from a cohort of 516 LGG tumors in The Cancer Genome Atlas and analyzed independent prognostic factors using LASSO regression and Cox proportional regression to build a network based on the correlation between SF-related survival AS events. We collected 100 patients from our center for immunohistochemistry and analyzed survival using χ2 test and Cox and Kaplan-Meier analyses. A total of 9,616 AS events related to LGG were screened and identified as well as established related models. Through analyzing specific splicing patterns in LGG, we screened 16 genes to construct a prognostic model to stratify the risk of LGG patients. Validation revealed that the expression level of the prognostic model in LGG tissue was increased, and patients with high expression showed worse prognosis. In summary, we demonstrated the role of SFs and AS events in the progression of LGG, which may provide insights into the clinical significance and aid the future exploration of LGG-associated AS.

[Small interfering RNA-mediated α-enolase knockdown suppresses glycolysis and proliferation of human glioma U251 cells in vitro].

OBJECTIVE: To investigate the role of α-enolase (ENO1) in regulating glucose metabolism and cell growth in human glioma cells. METHODS: Glucose uptake and lactate generation were assessed to evaluate the changes in glucose metabolism in human glioma U251 cells with small interfering RNA (siRNA)-mediated ENO1 knockdown. MTT assay and 5-ethynyl-2'-deoxyuridine (EdU) staining were used to examine the cell growth and cell cycle changes following siRNA transfection of the cells. RESULTS: Transfection of U251 cells with siRNA-ENO1 markedly reduced glucose uptake (P=0.023) and lactate generation (P=0.007) in the cells and resulted in significant suppression of cell proliferation (*P<0.05) since the second day following the transfection. Transfection with siRNA-ENO1 also obviously suppressed cell cycle G1/S transition in the cells (P=0.0425). The expressions of HK2 and LDHA, the marker genes for glucose metabolism, were significantly down-regulated in the cells with siRNA-mediated ENO1 knockdown. CONCLUSION: ENO1 as a potential oncogene promotes glioma cell growth by positively modulating glucose metabolism.

The effect of hippocampal NMDA receptor blockade by MK-801 on cued fear extinction.

Extinction of conditioned fear has been suggested to be a new form of learning instead of erasure of what was originally learned, and the process is NMDA (N-methyl d-aspartate) receptor (NMDAR) dependent. Most of studies have so far revealed the important roles of NMDARs in the amygdala and medial prefrontal cortex (mPFC) in cued fear extinction. Although the ventral hippocampus has intimately reciprocal connections with the amygdala and mPFC, the role of its NMDARs in cued fear extinction remains unclear. The present experiment explored the issue by bilateral pre-extinction microinjection of the noncompetitive NMDAR antagonist MK-801 into the ventral hippocampus. Four groups of rats were given habituation, tone cued fear conditioning, fear extinction training and extinction test. Prior to extinction training, rats received bilateral infusions of either MK-801 (1.5, 3, or 6µg/0.5µl) or saline. Our results showed that MK-801 reduced freezing on the first trial of extinction training with no impact on within-session acquisition of extinction, and that the lower doses of MK-801 resulted in increased freezing on the extinction retrieval test. These findings suggest that ventral hippocampal NMDARs are necessary for the consolidation of tone cued fear extinction.

Acclimatization to middle altitude hypoxia protects against developmental and cognitive deficits caused by acute fetal hypoxia in mice.

Acute fetal hypoxia (AFH) can elicit postnatal motor deficits and cognitive impairments. To test whether lifelong acclimatization to middle altitude (MA) hypoxia has protective effects on the impairments caused by AFH, ICR mice bred at 1 900 m altitude for 6-7 generations were evaluated under AFH. On gestation day 9 (GD 9), 13 (GD 13) or 17 (GD 17), pregnant mice received a single exposure to acute hypoxia (7% O2, 6 h). Physiological and neurodevelopmental behaviors, motor function (open field), spatial learning and memory (Morris water maze), and anxiety level (elevated plus maze) were examined in the offspring from neonate to adulthood. In the neonatal age, among all the physiological and behavioral landmarks, almost no differences were found in the hypoxia groups. In the juvenile period, no obvious impairments of motor function and anxiety level were found in the hypoxia groups. In the adult period, no obvious impairment of motor function was found in hypoxia groups; Interestingly, AFH groups' offspring showed normal or enhanced long-term spatial memory ability after AFH. These data suggest that AFH cause little abnormalities in the offspring of MA-adapted mice. To further investigate the underlying mechanisms, the neuronal numbers in behavior-related brain areas (accumbens nucleus, basal amygdala and hippocampus) were counted, and the physiological parameters of the blood were measured. The morphological data showed that no obvious neuronal necrosis was found in all hypoxia groups. In addition, blood tests showed that red blood corpuscle count, hemoglobin concentration and hematocrit levels in mice raised at MA were markedly higher in both males and females, compared with controls raised at the sea level. These data suggest that lifelong acclimatization to MA hypoxia has protective effects against development delay, motor deficits and spatial learning and memory impairments induced by AFH, and the protective effects may be due to higher hemoglobin concentration and hematocrit levels in the blood. The findings may provide a better understanding of fetal hypoxia and potential intervention treatments.

Interleukin-16 polymorphism is associated with an increased risk of glioma.

OBJECTIVE: Previous studies have shown that interleukin (IL)-16 is overexpressed in human and rat gliomas. Potential links between IL-16 polymorphisms and glioma risk are currently unclear. The aim of this study was to investigate the association between IL-16 polymorphisms and glioma risk. METHODS: We examined IL-16 gene polymorphisms (i.e., rs 4778889, rs 11556218, and rs 4072111) in 216 patients with glioma and 275 controls in a Chinese population. Genotypes were determined using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were used to evaluate the effect of the IL-16 polymorphisms on glioma risk. RESULTS: The rs 11556218TG genotype is associated with an increased risk of glioma compared with the TT genotype (OR=1.76; 95% CI, 1.22-2.54; p=0.002). Similarly, the rs 11556218G allele is associated with an increased risk of glioma compared with the T allele (OR=1.41; 95% CI, 1.06-1.87; p=0.017). However, no significant association was observed between the IL-16 rs 4778889 and rs 4072111 polymorphisms and the risk of glioma. CONCLUSION: These findings suggest that the IL-16 rs 11556218 polymorphism may be used as a susceptibility marker for glioma.

Maze model to study spatial learning and memory in freely moving monkeys.

Many types of mazes have been used in cognitive brain research and data obtained from those experiments, especially those from rodents' studies, support the idea that the hippocampus is related to spatial learning and memory. But the results from non-human primates researches regarding the role of the hippocampus in spatial learning and memory are controversial and inconsistent with those obtained in rodents. This might be due to the differences of the methods used in non-human primates and rodents. Several kinds of maze models including two-dimensional computerized visual maze models and three-dimensional maze models have been developed for non-human primates, but they all have some defects. Therefore, development of a maze model for non-human primates that is comparable with those used in rodents is necessary to solve the controversy. This paper describes a large-scale, three-dimensional outdoor maze model for non-human primates which can be used to study spatial learning and memory. Monkeys learn to use the maze quickly compared with two-dimensional computerized visual mazes. It has many advantages which could make up the limits of the existing three-dimensional mazes in non-human primates, and can be comparable with radial arm mazes used in rodents. Based on the results, we believe that the new maze model will be valuable in many research areas, especially in studies involving spatial learning and memory in freely moving monkeys.