[Ginsenoside Rg_1 ameliorates OGD/R-induced PC12 cell injury by inhibiting autography via IRE1-JNK-CHOP pathway].

This study investigated the protective effect of ginsenoside Rg_1(GRg_1) on oxygen and glucose deprivation/reoxygenation(OGD/R)-injured rat adrenal pheochromocytoma(PC12) cells and whether the underlying mechanism was related to the regulation of inositol-requiring enzyme 1(IRE1)-c-Jun N-terminal kinase(JNK)-C/EBP homologous protein(CHOP) signaling pathway. An OGD/R model was established in PC12 cells, and PC12 cells were randomly classified into control, model, OGD/R+GRg_1(0.1, 1, 10 µmol·L~(-1)), OGD/R+GRg_1+rapamycin(autophagy agonist), OGD/R+GRg_1+3-methyladenine(3-MA,autophagy inhibitor), OGD/R+GRg_1+tunicamycin(endoplasmic reticulum stress agonist), OGD/R+GRg_1+4-phenylbutyric acid(4-PBA, endoplasmic reticulum stress inhibitor), and OGD/R+GRg_1+3,5-dibromosalicylaldehyde(DBSA, IRE1 inhibitor) groups. Except the control group, the other groups were subjected to OGD/R treatment, i.e., oxygen and glucose deprivation for 6 h followed by reoxygenation for 6 h. Cell viability was detected by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide(MTT) assay. Apoptosis was detected by Hoechst 33342 staining, and the fluorescence intensity of autophagosomes by the monodansylcadaverine(MDC) assay. Western blot was employed to determine the expression of autophagy-related proteins(Beclin1, LC3-Ⅱ, and p62) and the pathway-related proteins [IRE1, p-IRE1, JNK, p-JNK, glucose-regulated protein 78(GRP78), and CHOP]. The results showed that GRg_1 dose-dependently increased the viability of PC12 cells and down-regulated the expression of Beclin1, LC3-Ⅱ, p-IRE1, p-JNK, GRP78, and CHOP, compared with the model group. Furthermore, GRg_1 decreased the apoptosis rate and MDC fluorescence intensity and up-regulated the expression of p62 protein. Compared with the OGD/R+GRg_1(10 µmol·L~(-1)) group, OGD/R+GRg_1+rapamycin and OGD/R+GRg_1+tunicamycin groups showed increased apoptosis rate and MDC fluorescence intensity, up-regulated protein levels of Beclin1, LC3-Ⅱ, p-IRE1, p-JNK, GRP78, and CHOP, decreased relative cell survival rate, and down-regulated protein level of p62. The 3-MA, 4-PBA, and DBSA groups exerted the opposite effects. Taken together, GRg_1 may ameliorate OGD/R-induced PC12 cell injury by inhibiting autophagy via the IRE1-JNK-CHOP pathway.

Sodium Sulfite as a Novel Hypoxia Revulsant Involved in Hypoxic Regulation in Escherichia coli.

As a reducing salt, sodium sulfite could deprive oxygen in solution, which could mimic hypoxic stress in Caenorhabditis elegans. In this study, the wild-type Escherichia coli strain MG1655 was used to examine the inhibition of sodium sulfite-induced hypoxia by observing the bacterial growth curves. We also analyzed the growth curves of mutant strains (for arcA/B, soxR/S, fnr, and oxyR) related to E. coli hypoxic pathways to reveal roles of the related genes during hypoxia. The ultrastructure of hypoxia-inhibited bacteria were also observed using transmission electron microscopy. Sodium sulfite could maintain hypoxic condition of bacterial culture for 8 h with concentrations over 40 mmol/L. Complete ultrastructure of the bacteria indicated sodium sulfite did inhibit bacterial growth and division. Among the hypoxia genes, fnr and arcB played key roles in sodium sulfite-induced hypoxia. This study showed that sodium sulfite could be used as a novel hypoxia revulsant for bacterial cultures.

[Protective effect of Tongqiao Huoxue Decoction containing cerebrospinal fluid on OGD/R-damaged HT22 cells via regulation of ASK1/MKK4/JNK signaling pathway].

To investigate the protective effect of Tongqiao Huoxue Decoction containing cerebrospinal fluid(TQHXD-CSF) on HT22 cells damaged by oxygen-glucose deprivation/reoxygenation(OGD/R) and whether the mechanism is related to the regulation of ASK1/MKK4/JNK signaling pathway. HT22 cells were subjected to OGD/R to simulate cerebral ischemia-reperfusion injury(CIRI). Then the cells were randomly divided into five groups: blank cerebrospinal fluid(control group), OGD/R group, TQHXD-CSF group, Z-VAD-FMK group(20 µmol·L~(-1)) and TQHXD-CSF+Z-VAD-FMK group. Except the control group, cells in the other groups were reoxygenated for 12 h after 6 h of oxygen and glucose deprivation for modeling OGD/R, and group administration was performed. Cell viability and cytotoxicity were detected by CCK8 and LDH assay kit, respectively and the morphology of HT22 cells was observed by inverted microscope. Western blot and qRT-PCR were employed to detect the protein and mRNA expression levels of Bax, Bcl-2 and caspase-3, respectively. Then HT22 cells were assigned into the control group, OGD/R group, si-NC group, si-ASK1 group, TQHXD-CSF group and TQHXD-CSF+si-ASK1 group. Cell viability, proliferation and apoptosis were determined by CCK8, electric cell-substrate impedance sensing(ECIS), and Hoechst staining and flow cytometry, respectively. The protein expression of MKK4, p-MKK4, JNK, p-JNK, c-Jun, p-c-Jun, Cyt C, Bax, Bcl-2 and caspase-3 was tested by Western blot. The results showed that compared with OGD/R group, TQHXD-CSF significantly enhanced cell viability, improved cell morphology and reduced the protein and mRNA expression levels of Bax, Bcl-2 and caspase-3. In addition, when ASK1 was silenced, compared with OGD/R group, TQHXD-CSF remarkably improved cell viability, and decreased apoptosis rate and the protein expression levels of p-MKK4, p-JNK, p-c-Jun, Cyt C, Bax/Bcl-2 and caspase-3, but the effect was not as good as that of TQHXD-CSF+si-ASK1 group. In conclusion, TQHXD-CSF can inhibit apoptosis mediated by ASK1/MKK4/JNK signaling pathway in OGD/R-damaged HT22 cells, and has protective effect on ischemia-reperfusion injury.

NMMHC IIA Inhibition Ameliorates Cerebral Ischemic/Reperfusion-Induced Neuronal Apoptosis Through Caspase-3/ROCK1/MLC Pathway.

PURPOSE: Our previous studies have indicated that non-muscle myosin heavy chain IIA (NMMHC IIA) is involved in H2O2-induced neuronal apoptosis, which is associated with the positive feedback loop of caspase-3/ROCK1/MLC pathway. However, the neuroprotective effect of NMMHC IIA inhibition with an adeno-associated virus (AAV) vector after transient middle cerebral artery occlusion (MCAO) and its role in caspases-3/ROCK1/MLC pathway remain blurred. METHODS: Green fluorescent protein (GFP) and a small hairpin RNA targeting Myh9 (encoding NMMHC IIA) were cloned and packaged into the AAV9 vector. AAV-shMyh9 or control vector were injected into C57BL/6J mice four weeks prior to 60 min MCAO. Twenty-four hours after reperfusion, functional and histological analyses of the mice were performed. RESULTS: In this study, AAV-shMyh9 was used to down-regulate NMMHC IIA expression in mice. We found that down-regulation of NMMHC IIA could improve neurological scores and histological injury in ischemic mice. Ischemic attack also activated neuronal apoptosis, and this effect was partially attenuated when NMMHC IIA was inhibited by AAV-shMyh9. In addition, AAV-shMyh9 significantly reduced cerebral ischemic/reperfusion (I/R)-induced NMMHC IIA-actin interaction, caspase-3 cleavage, Rho-associated kinase1 (ROCK1) activation and myosin light-chains (MLC) phosphorylation. CONCLUSION: Consequently, we showed that AAV-shMyh9 inhibits I/R-induced neuronal apoptosis linked with caspase-3/ROCK1/MLC/NMMHC IIA-actin cascade, which has also been confirmed to be a positive feedback loop. These findings put some insights into the neuroprotective effect of AAV-shMyh9 associated with the regulation of NMMHC IIA-related pathway under ischemic attack and provide a therapeutic strategy for ischemic stroke.

Sweroside ameliorates α-naphthylisothiocyanate-induced cholestatic liver injury in mice by regulating bile acids and suppressing pro-inflammatory responses.

AIM: Sweroside is an iridoid glycoside with diverse biological activities. In the present study we investigated the effects of sweroside on α-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury in mice. METHODS: Mice received sweroside (120 mg·kg(-1)·d(-1), ig) or a positive control INT-747 (12 mg·kg(-1)·d(-1), ig) for 5 d, and ANIT (75 mg/kg, ig) was administered on d 3. The mice were euthanized on d 5, and serum biochemical markers, hepatic bile acids and histological changes were analyzed. Hepatic expression of genes related to pro-inflammatory mediators and bile acid metabolism was also assessed. Primary mouse hepatocytes were exposed to a reconstituted mixture of hepatic bile acids, which were markedly elevated in the ANIT-treated mice, and the cell viability and expression of genes related to pro-inflammatory mediators were examined. RESULTS: Administration of sweroside or INT-747 effectively ameliorated ANIT-induced cholestatic liver injury in mice, as evidenced by significantly reduced serum biochemical markers and attenuated pathological changes in liver tissues. Furthermore, administration of sweroside or INT-747 significantly decreased ANIT-induced elevation of individual hepatic bile acids, such as ß-MCA, CA, and TCA, which were related to its effects on the expression of genes responsible for bile acid synthesis and transport as well as pro-inflammatory responses. Treatment of mouse hepatocytes with the reconstituted bile acid mixture induced significant pro-inflammatory responses without affecting the cell viability. CONCLUSION: Sweroside attenuates ANIT-induced cholestatic liver injury in mice by restoring bile acid synthesis and transport to their normal levels, as well as suppressing pro-inflammatory responses.

Effects of Muscone on the Expression of P-gp, MMP-9 on Blood-Brain Barrier Model In Vitro.

Muscone is the main chemical ingredient in Musk which is main crude drug in Tongqiaohuoxue decoction (TQHXD), and TQHXD has a protective effect on damaged neurons, so we hypothesize that muscone can alter blood-brain barrier (BBB) permeability via the modulation of P-glycoprotein (P-gp) and matrix metalloproteinase-9 (MMP-9) expression. In this study, astrocytes (AC) and human umbilical vein endothelial cells (ECV304) were co-cultured to simulate the BBB model in vitro. Leak testing, transmembrane resistance experiments, and BBB-specific enzyme testing were used to test whether the model was successful. Different concentrations of muscone permeating the BBB were detected by gas chromatography (GC). The change of the transendothelial electrical resistance (TEER) on the BBB in vitro after treating with muscone was detected by Millicell-ERS. The protein expression of P-gp, MMP-9 in normal, and oxygen/glucose deprivation (OGD) BBB model was determined by western blotting to inquire that the mechanism of muscone penetrates the BBB model in vitro. The results show that muscone was detected in the lower medium of the BBB model by GC; the values of TEER were no significant difference before and after muscone (8 µM) was added to the BBB model; the expression of P-gp significantly decreased after the BBB model treatment with muscone (4, 8, and 16 µM) for 24 h; the expression of P-gp and MMP-9 in different concentrations of muscone groups had different degrees of reduction compared with the BBB in the state of OGD. In conclusion, muscone could permeate the BBB model, and it was associated with the inhibition of P-gp and MMP-9 expression. An understanding of the mechanisms of muscone across the BBB is crucial to the development of therapeutic modalities for cerebral vascular diseases.

[Protective effect of ligustilide against glutamate-induced apoptosis in PC12 cells].

To investigate the neuroprotective of ligustilide (LIG) against glutamate-induced apoptosis of PC12 cells, cell viability were examined by MTT assay. Flow cytometry was applied to assay cell apoptosis rate. Intracellular calcium concentration was measured by using fluorescent dye Fluo-3/AM. Cytochrome C (Cyt C), Caspase-3, Bax and Bcl-2 protein expression were assayed by western blot. The results showed that glutamate is cytotoxic with an inhibitory concentration 50 (ID50) of 15 mmol · L(-1). Pretreatment with LIG (1, 5, 15 µmol · L(-1)) significantly improved cell viability. The apoptosis rate in glutamate-induced PC12 cells was 13.39%, and decreased in the presence of LIG (1, 5, 15 µmol · L(-1)) by 9.06%, 6.48%, 3.82%, separately. Extracellular accumulation of Ca2+ induced by glutamate were significantly reduced by LIG. The results of western blot manifested that pretreatment LIG could decrease the release of Cyt C from mitochondria, down-regulate Caspase-3 protein expression and up-regulate Bcl-2/Bax ratio, thereby protects PC12 cells from apoptosis. In summary, LIG had protective effect on glutamate-induced apoptosis in PC12 cells through attenuating the increase in intracellular Ca2+ concentration, and inhibiting the release of Cyt C from mitochondria to cytoplasm.

In vitro model of the blood-brain barrier established by co-culture of primary cerebral microvascular endothelial and astrocyte cells.

Drugs for the treatment and prevention of nervous system diseases must permeate the blood-brain barrier to take effect. In vitro models of the blood-brain barrier are therefore important in the investigation of drug permeation mechanisms. However, to date, no unified method has been described for establishing a blood-brain barrier model. Here, we modified an in vitro model of the blood-brain barrier by seeding brain microvascular endothelial cells and astrocytes from newborn rats on a polyester Transwell cell culture membrane with 0.4-µm pores, and conducted transepithelial electrical resistance measurements, leakage tests and assays for specific blood-brain barrier enzymes. We show that the permeability of our model is as low as that of the blood-brain barrier in vivo. Our model will be a valuable tool in the study of the mechanisms of action of neuroprotective drugs.

[The correlation of human serum Lp-PLA2 and hs-CRP and stability of coronary atherosclerotic plaques].

OBJECTIVE: To explore the relationship of serum lipoprotein-associated phospholipase A2 and high sensitive C-reactive protein in vulnerable coronary atherosclerotic plaques. METHODS: Patients undergoing coronary angiography (CAG) were examined for CAD with intravascular ultrasound (IVUS). According to the findings of CAG and IVUS, all the patients were divided into three groups: a control group without plaque, stable plaque group and vulnerable plaque group. The total serum Lp-PLA2 and hs-CRP were measured before angiography and they were valued with T test and Pearson's correlation analysis. RESULTS: (1) Lp-PLA2 level in stable plaque group and vulnerable plaque group was higher than that in control group (P < 0.05). (2) Lp-PLA2 level in the vulnerable plaque group was higher than that in stable plaque group (P < 0.05). (3) hs-CRP level in the vulnerable plaque group is higher than that in the stable plaque group and control group (P < 0.05) and there was significant difference between them. (4) To discriminate vulnerable plaque, the specificity of serum Lp-PLA2 was stronger than that of hs-CRP. CONCLUSIONS: Serum Lp-PLA2 level has higher sensitivity in predicting the vulnerability of the coronary atherosclerotic plaque than hs-CRP. In combination with hs-CRP, we can use Lp-PLA2 as a new biomarker to predict the presence of vulnerable plaque.

Effect of the quality of the interaction data on predicting protein function from protein-protein interactions.

Protein function prediction is an important issue in the post-genomic era. When protein function is deduced from protein interaction data, the traditional methods treat each interaction sample equally, where the qualities of the interaction samples are seldom taken into account. In this paper, we investigate the effect of the quality of protein-protein interaction data on predicting protein function. Moreover, two improved methods, weight neighbour counting method (WNC) and weight chi-square method (WCHI), are proposed by considering the quality of interaction samples with the neighbour counting method (NC) and chi-square method (CHI). Experimental results have shown that the qualities of interaction samples affect the performances of protein function prediction methods seriously. It is also demonstrated that WNC and WCHI methods outperform NC and CHI methods in protein function prediction when example weights are chosen properly.