GP-14 protects against severe hypoxia-induced neuronal injury through the AKT and ERK pathways and its induced transcriptome profiling alteration.

Gypenosides are major bioactive ingredients of G. pentaphyllum. In our previous study, we found that gypenosides had neuroprotective effects against hypoxia-induced injury. In the current study, we focused on the protective effects of gypenoside-14 (GP-14), which is one of the newly identified bioactive components, on neuronal injury caused by severe hypoxia (0.3% O2). The results showed that GP-14 pretreatment alleviated the cell viability damage and apoptosis induced by hypoxia in PC12 cells. Moreover, GP-14 pretreatment also attenuated primary neuron injuries under hypoxic conditions. Additionally, GP-14 pretreatment significantly ameliorated neuronal damage in the hippocampal region induced by high-altitude cerebral edema (HACE). At the molecular level, GP-14 pretreatment reversed the decreased activities of the AKT and ERK signaling pathways caused by hypoxia in PC12 cells and primary neurons. To comprehensively explore the possible mechanisms, transcriptome sequencing was conducted, and these results indicated that GP-14 could alter the transcriptional profiles of primary neuron. Taken together, our results suggest that GP-14 acts as a neuroprotective agent to protect against neuronal damage induced by severe hypoxia and it is a promising compound for the development of neuroprotective drugs.

[Effects of blocking lactate production by 2-DG on hypoxic injury of HT22 neurons and its mechanisms].

OBJECTIVE: To investigate the effects of blocking lactate synthesis on the HT22 cell injuries caused by hypoxia. METHODS: 2-deoxy-D-glucose (2-DG) is a non-metabolized glucose analogue that can inhibit lactate synthesis by blocking glycolysis. HT22 cells were divided into 4 groups: Control group, 2-DG group, Hypoxia group and 2-DG+Hypoxia group. The cells in control group and 2-DG treatment group were cultured in a 37℃, 5% CO2 incubator, and thecells in hypoxia group and 2-DG + Hypoxia group were cultured in a hypoxia incubator. The concentrations of 2-DG were 2.5 and 5 mmol/L, the concentration of oxygen was 0.3%, and the treatment time was 24 h. Cell activity was detected by CCK-8 assay, the levels of lactate in cell culture medium were detected by spectrophotometry, cell morphology was observed by fluorescence staining, the level of reactive oxygen species (ROS) was detected by flow cytometry, and the activities of superoxide dismutase (SOD) and catalase (CAT) were determined by enzyme activity kits. The protein expression levels of p-p38, t-p38 and ß-actin were detected by Western blot. RESULTS: Compared with that in control group, the lactate level in culture medium and cell activity were decreased significantly (P＜0.01), the number of adherent cells was decreased, the level of ROS was increased (P＜0.01), and the enzyme activity of CAT was decreased (P＜0.05) in the 2-DG group. In the hypoxia group, the level of lactate in the culture medium was increased significantly (P＜0.01), the cell activity was decreased (P＜0.01), the number of adherent cells was decreased, the ROS levels were increased (P＜0.01), and the enzyme activities of CAT and SOD were decreased (P＜0.01 or P＜0.05). In 2-DG+Hypoxia group, the level of lactate was decreased significantly (P＜0.05), the cell viability was decreased significantly (P＜0.01), the number of cells was decreased significantly, and the ability of adhere to the wall was weakened significantly. The level of ROS was increased significantly (P＜0.01), the enzyme activities of CAT and SOD were decreased significantly (P＜0.01), the protein expression level of p-p38 was increased significantly (P＜0.05), and there was no change in t-p38. Compared with hypoxia groups, in 2-DG combined with hypoxia group, the level of lactate induced by hypoxia, the cell activity, and the enzyme activity level of CAT were decreased significantly (all P＜0.01), while the level of ROS was increased significantly (P＜ 0.01). CONCLUSION: Blocking lactate can reduce the cell activity level under hypoxia and aggravate the oxidative stress injury of HT22 cells. The mechanisms may be related to increasing ROS level and activating p38 signal pathway.

[Association of FGF23 gene polymorphism with Kawasaki disease and coronary artery lesions].

OBJECTIVE: To study the distribution of polymorphism of c.212-37insC (rs3832879) in intron 1 of fibroblast growth factor 23 (FGF23) gene and its association with Kawasaki disease (KD) and coronary artery lesions (CAL). METHODS: Forty children with KD were enrolled in this study, among whom 16 children had concurrent CAL. Twenty-six age-matched healthy children were enrolled as controls. PCR and gene sequencing were applied to explore the distribution of polymorphism of c.212-37insC (rs3832879) in FGF23 gene in KD patients and controls. RESULTS: Among 40 children with KD, 14 (35%) carried the polymorphism of c.212-37insC (rs3832879) in FGF23 gene; among 26 controls, 6 (23%) carried such polymorphism. There was no significant difference in genotype distribution at this locus between the two groups (P=0.30). Among 16 children with CAL, 9 (56%) carried the polymorphism at this locus; among 24 children without CAL, 5 (21%) carried such polymorphism. As for the comparison of two subgroups with and without CAL, the difference in genotype distribution at this locus had statistical significance (P=0.02, OR=4.89, 95% CI: 1.21-19.71). CONCLUSIONS: The polymorphism of c.212-37insC (rs3832879) in FGF23 gene may not be associated with the pathogenesis of childhood KD, but it may be associated with the development of CAL in children with KD.