Significance of Single-Nucleotide Variants in Long Intergenic Non-protein Coding RNAs

Single-nucleotide variants (SNVs) are the most common genetic variants and universally present in the human genome. Genome-wide association studies (GWASs) have identified a great number of disease or trait-associated variants, many of which are located in non-coding regions. Long intergenic non-protein coding RNAs (lincRNAs) are the major subtype of long non-coding RNAs; lincRNAs play crucial roles in various disorders and cellular models via multiple mechanisms. With rapid growth in the number of the identified lincRNAs and genetic variants, there is great demand for an investigation of SNVs in lincRNAs. Hence, in this article, we mainly summarize the significant role of SNVs within human lincRNA regions. Some pivotal variants may serve as risk factors for the development of various disorders, especially cancer. They may also act as important regulatory signatures involved in the modulation of lincRNAs in a tissue- or disorder-specific manner. An increasing number of researches indicate that lincRNA variants would potentially provide additional options for genetic testing and disease risk assessment in the personalized medicine era.

MicroRNA-26a-2 maintains stress resiliency and antidepressant efficacy by targeting the serotonergic autoreceptor HTR1A

The association between dysregulated serotonergic activity and major depressive disorder (MDD) is well known. However, the various mechanisms underlying serotonergic dysregulation in MDD remain unclear. Previous research on serotonergic (5-HT) neurons identified microRNA-26a (miR-26a) targeting of the serotonin autoreceptor, 5-HT receptor 1A (HTR1A). Reporter assays with the Htr1a 5'UTR sequence were performed in vitro. Adult transgenic mouse models altering miR-26a-2 and Htr1a expression were used for chronic social defeat, antidepressant treatment, and in vivo lentiviral experiments. Mice were tested for anxiety-like behavior using the elevated plus-maze, dark-light transfer, and open-field tests, and for depression-like behavior using the forced-swim test. We confirmed that miR-26a-2 downregulates Htr1a expression in 5-HT neurons in vitro. miR-26a-2 levels were significantly upregulated in the mouse dorsal raphe nucleus (DRN) following antidepressant therapy. The transgenic murine model overexpressing miR-26a-2 in serotonergic neurons displayed improved behavioral resiliency to social defeat. These effects were abrogated by the addition of Htr1a overexpression. In contrast, the transgenic murine model with miR-26a-2 knockdown in serotonergic neurons displayed increased anxious behavior and weakened antidepressant response. These effects were rescued by silencing Htr1a expression. Our findings suggest that miR-26a-2 functions as an endogenous antidepressant by targeting HTR1A in serotonergic neurons.

[Analysis of the factors affecting the efficacy of (131)I remnant ablation in patients after thyroidectomy for papillary thyroid microcarcinoma]

Objective: To investigate the influential factors of efficacy of the first (131)I ablation therapy for thyroid remnant in papillary thyroid microcarcinoma (PTMC) patients after thyroidectomy. Methods: Eighty-nine PTMC patients who underwent twice (131)I ablation therapy and (131)I whole body follow-up scan ((131)I-WBS) within 5 to 8 months in our department from September 2007 to October 2016 were identified and enrolled in present study. Patients were divided into complete-ablation group and uncomplete-ablation group according to whether or not radioactivity was detected at the thyroid bed in (131)I-WBS. The χ(2) test and multi-variance Binary logistic regression were performed for the factors which might affect the therapeutic efficacy. Results: The first (131)I ablation therapy was successful in 41 of 89 patients (46.07%). Residual thyroid weight was found to be associated with therapeutic efficacy (P<0.05), while gender, age, surgical method, lesions'maximum diameter, with or without LN metastasis, with or without distant metastasis, time of operation from first (131)I treatment, lesions'number, thyroid stimulating hormone (TSH), thyroglobulin (Tg), the consistency of (131)I-WBS and (99)Tc(m)-pertechnatate, TNM stage, ATA risk, Tg/TSH ratio were not significant associated with therapeutic efficacy. Binary logistic regression analysis was performed in these respects and it indicated that residual thyroid weight and ATA risk were not statistically significant independent variable (P>0.05). Conclusions: Residual thyroid weight might affect efficacy of the first (131)I ablation therapy on thyroid remnant in PTMC patients after thyroidectomy, but it is not an independent factor. Multiple interrelated factors should be considered when predicting the efficacy of the first (131)I ablation therapy.

Association between Ca/Mg/P status and suppurative tonsillitis in children

Suppurative tonsillitis (ST) is a common respiratory disease in children. This study aims to investigate the association between calcium (Ca)/magnesium (Mg)/phosphorus (P) and the risk of onset of suppuration in tonsillitis in children. Seventy children with ST and 61 age- and sex-matched children with non-ST were enrolled in this study. The association between Ca/Mg/P and suppuration risk in tonsillitis was investigated. The relationship between Ca/Mg/P and the potential risk factors for ST were also studied. White blood cell (WBC), platelet (PLT), c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels were significantly higher in the ST group than those in the non-ST group (p less than 0.05). Mg and P levels were significantly lower in the ST group than those in the non-ST group (p less than 0.05). There was no obvious difference in Ca level between the ST group and the non-ST group (p=0.762). A significantly negative association between P and PCT was noted (r=-0.236, p=0.035). The results indicated that Mg/P disorder may be associated with the susceptibility to suppuration in children with tonsillitis, inflammatory indexes may reflect this risk.

lncRNAs PVT1 and HAR1A are prognosis biomarkers and indicate therapy outcome for diffuse glioma patients

Diffuse gliomas are well known malignant brain tumors. Long non-coding RNAs (lncRNAs), a type of RNA transcript with more than 200 nucleotides, involve in tumorigenesis and development of various cancers. This study focused on identifying differentially expressed lncRNAs in gliomas based on gene expression profiling, and chose certain lncRNAs PVT1, CYTOR, HAR1A and MIAT, which changed with significant differences. Further analysis of TCGA and GEO data revealed that the expressions of PVT1 and CYTOR were up-regulated, while HAR1A and MIAT expressions were down-regulated in gliomas. Their expression patterns were validated in an independent cohort containing 98 glioma specimens and 12 non-tumor tissue controls. High expression of PVT1 and CYTOR as well as low HAR1A and MIAT expression were associated with high Ki-67 level and more TP53 mutation. Kaplan-Meier survival curve and Cox regression analyses showed that glioma patients with high PVT1 expression or low HAR1A expression had poor survival outcome, aberrantly expressed PVT1 and HAR1A could be the independent prognosis biomarkers for glioma patients. Moreover, down-regulation of PVT1 and up-regulation of HAR1A contributed to improve the survival of patients who received chemotherapy and radiotherapy. These results implied that these four lncRNAs might play important role in diffuse gliomas progression, particularly, PVT1 and HAR1A could be explored as promising biomarkers for diagnosis, prognosis and target therapy of diffuse gliomas.

Combined Influence of Genetic Polymorphism and DNA Methylation on ABCB1 Expression and Function in Healthy Chinese Males

BACKGROUND AND OBJECTIVES

It is well known that the expression and function of ATP-binding cassette transporter B1 (ABCB1) show high interindividual variability, but the reasons have not yet been fully elucidated. In this study, combined influence of genetic polymorphism and DNA methylation on ABCB1 mRNA expression and digoxin pharmacokinetics in healthy Chinese males was analyzed.

METHODS

A total of 93 subjects who were homozygous for the ABCB1 1236-2677-3435 TTT or CGC haplotype were enrolled in this study. DNA methylation status of the ABCB1 promoter and ABCB1 mRNA expression level in exfoliated intestinal epithelial cells were analyzed using bisulfite sequencing PCR and real-time PCR. The pharmacokinetics of digoxin in subjects were investigated after administration of a single oral dose of digoxin 0.5 mg.

RESULTS

The DNA methylation levels of ABCB1 promoter showed no significant difference between TTT/TTT and CGC/CGC carriers (P = 0.54). Subjects with TTT/TTT haplotype pair and high methylation status (TTT/TTT-HM) showed a significantly lower ABCB1 mRNA level compared to other subjects. Compared with TTT/TTT-HM subgroup, the area under the plasma concentration-time curve from time zero to 72 h (AUC_0-72) of digoxin was decreased by 26.9 %, the maximum plasma concentration (C _max) was decreased by 25 % and the apparent oral clearance (CL/F) was increased by 21.2 % in CGC/CGC-LM subgroup. The values of time to maximum concentration (t _max) and terminal elimination half-life (t _1/2) showed no significant difference.

CONCLUSIONS

Both genetic polymorphism and DNA methylation variation should be taken into consideration to explain the interindividual variability in ABCB1 expression and function more clearly.

AKT Axis, miR-21, and RECK Play Pivotal Roles in Dihydroartemisinin Killing Malignant Glioma Cells

Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, is known to play important roles in inhibiting proliferation rate, inducing apoptosis, as well as hindering the metastasis and invasion of glioma cells, but the underlying mechanisms are still unclear so far. In this study, methyl thiazolyl tetrazolium (MTT), colony-forming, wound healing, invasion, and apoptosis assays were performed to investigate the effect of DHA on malignant glioma cells. Results showed that DHA induced apoptosis of malignant glioma cells through Protein Kinase B (AKT) axis, induced death of malignant glioma cells by downregulating miR-21, and inhibited the invasion of malignant glioma cells corresponding with up-regulation of the reversion-inducing-cysteine-rich protein with kazal motifs (RECK). These results revealed that AKT axis, miR-21, and RECK play pivotal roles in DHA killing malignant glioma cells, suggesting that DHA is a potential agent for treating glioma.

Extensible chip of optofluidic variable optical attenuator

A core chip of optofluidic variable optical attenuator (VOA) is reported. The chip, with a simple structure, utilizes microfluid and compressed air to regulate the optical attenuation, and it can be expanded to form a number of VOAs by using different microfluidic driving technologies. Three VOAs based on this chip and different driving technologies are introduced. The theoretical and experimental results show that the proposed chip possesses the advantages of large optical attenuation range (> 50dB) and low insertion loss (0.55 dB). Moreover it is a broadband optical device which can be operated in visible and near infrared wavelengths. The proposed chip provides a new method for seeking miniaturized VOAs with good performances, and it is promising to develop a number of different VOAs.

Significant association between the MTHFR A1298C polymorphism and hepatocellular carcinoma risk: a meta-analysis

The A1298C polymorphism of the methylenetetrahydrofolate reductase (MTHFR) gene has been reported to be associated with hepatocellular carcinoma (HCC), but there are conflicting results from previous studies. The present study aimed to investigate the association between this polymorphism and the risk of HCC using a meta-analysis of the published studies. Published literature from PubMed and Embase databases was systematically searched to identify relevant studies before October 2014. The Begg test was used to measure publication bias. Sensitivity analyses were performed to ensure the authenticity of the outcome. The meta-analysis results showed significant association between the MTHFR A1298C polymorphism and HCC risk (CC vs AA: OR = 0.52, 95%CI = 0.33-0.81; CC vs AC: OR = 0.50, 95%CI = 0.32-0.79; dominant model: OR = 1.94, 95%CI = 1.24-3.02; recessive model: OR = 1.00, 95%CI = 0.84-1.18). In the subgroup analysis, significant associations between the MTHFR A1298C polymorphism and HCC risk were found in Asians (CC vs AA: OR = 0.46, 95%CI = 0.27-0.78; CC vs AC: OR = 0.41, 95%CI = 0.24-0.71; dominant model: OR = 2.27, 95%CI = 1.33-3.86; recessive model: OR = 1.03, 95%CI = 0.86-1.24). Our results suggest that the MTHFR A1298C polymorphism might be related to increased risk of HCC in Asians. Further large and well-designed studies are needed to confirm these conclusions.

Effect of HIF-1a/VEGF signaling pathway on plasma progesterone and ovarian prostaglandin F₂a secretion during luteal development of pseudopregnant rats

The corpus luteum is a temporary endocrine structure in mammals that plays an important role in the female reproductive cycle and is formed from a ruptured and ovulated follicle with rapid angiogenesis. Vascular endothelial growth factor (VEGF) is thought to be vital in normal and abnormal angiogenesis in the ovary, but the molecular regulation of luteal VEGF expression during corpus luteum development in vivo is still poorly understood at present. Therefore, we examined whether hypoxia-inducible factor-1a (HIF-1a) is induced and regulates VEGF expression and luteal function in vivo using a pseudopregnant rat model treated with a small-molecule inhibitor of HIF-1a, echinomycin. Corpus luteum development in the pseudopregnant rat ovary was determined after measuring plasma progesterone concentration and ovarian prostaglandin F2a content to reflect changes in HIF-1a and VEGF on different days of this developmental process. At day 7, the corpus luteum was formed and the expression of HIF- 1a/VEGF reached a maximum, while a significant decrease in HIF-1a/ VEGF expression was observed when luteolysis occurred at day 13. Additionally, echinomycin blocked luteal development by inhibiting VEGF expression mediated by HIF-1a and following luteal function by detecting the progesterone changes at day 7. These results demonstrated that HIF-1a-mediated VEGF expression might be an important mechanism regulating ovarian luteal development in mammals in vivo, which may provide new strategies for fertility control and for treating some types of ovarian dysfunction, such as polycystic ovarian syndrome, ovarian hyperstimulation syndrome, and ovarian neoplasia.

Interindividual epigenetic variation in ABCB1 promoter and its relationship with ABCB1 expression and function in healthy Chinese subjects

AIM

Interindividual epigenetic variation is likely to be an important mechanism contributing to the interindividual variability in the expression and function of ATP-binding cassette, sub-family B, member 1 (ABCB1). The aim of the present study was to explore the effect of interindividual epigenetic variability in the ABCB1 promoter on ABCB1 expression and function in healthy Chinese subjects.

METHODS

Using bisulfite sequencing polymerase chain reaction (PCR) and chromatin immunoprecipitation assays, the DNA methylation and histone acetylation status of the ABCB1 promoter in stool DNA and exfoliated colonic epithelial cells of 157 healthy Chinese male volunteers was analysed. ABCB1 mRNA levels in colonic epithelial cells were detected by real-time PCR. The digoxin pharmacokinetics in subjects with different epigenetic profiles was investigated after a single oral administration of digoxin (0.5 mg).

RESULTS

The methylation levels of ABCB1 promoter in stool DNA showed a significant interindividual variation, from 0.84% to 18.05%. A high methylation level of the ABCB1 promoter was closely related to the low levels of acetylated histone H3 and ABCB1 mRNA expression. In the high methylation group, the area under the concentration-time curves (AUC(0-4 h) and AUC(0-10 h) ) of digoxin was increased by 19% [95% confidence interval (CI) 10%, 31%; P = 0.024] and 13% (95% CI 8%, 26%; P = 0.026), respectively, and the peak concentration (Cmax ) of digoxin was increased by 30% (95% CI 12%, 41%; P = 0.021) compared with the low methylation group.

CONCLUSIONS

The epigenetic modifications of the ABCB1 promoter show high interindividual variability in healthy Chinese subjects, and are closely related to the interindividual variation in ABCB1 mRNA expression and digoxin 0-4 h plasma concentrations in vivo.

Advances in molecular signaling mechanisms of β-phenethyl isothiocyanate antitumor effects

β-Phenethyl isothiocyanate (PEITC) is an important phytochemical from cruciferous vegetables and is being evaluated for chemotherapeutic activity in early phase clinical trials. Moreover, studies in cell culture and in animals found that the anticarcinogenic activities of PEITC involved all the major stages of tumor growth: initiation, promotion, and progression. A number of mechanisms have been proposed for the chemopreventive activities of this compound. Here, we focus on the major molecular signaling pathways for the anticancer activities of PEITC. These include (1) activation of apoptosis pathways; (2) induction of cell cycle arrest; and (3) inhibition of the survival pathways. Furthermore, we also discussed the regulation of drug-metabolizing enzymes, including cytochrome P450s, metabolizing enzymes, and multidrug resistance.

Genomic screening for targets regulated by berberine in breast cancer cells

Berberine, a common isoquinoline alkaloid, has been shown to possess anti-cancer activities. However, the underlying molecular mechanisms are still not completely understood. In the current study, we investigated the effects of berberine on cell growth, colony formation, cell cycle distribution, and whether it improved the anticancer efficiency of cisplatin and doxorubicin in human breast cancer estrogen receptor positive (ER+) MCF-7 cells and estrogen receptor negative (ER-) MDA-MB-231 cells. Notably, berberine treatment significantly inhibited cell growth and colony formation in the two cell lines, berberine in combination with cisplatin exerting synergistic growth inhibitory effects. Accompanied by decreased growth, berberine induced G1 phase arrest in MCF-7 but not MDA-MB-231 cells. To provide a more detailed understanding of the mechanisms of action of berberine, we performed genome-wide expression profiling of berberine-treated cells using cDNA microarrays. This revealed that there were 3,397 and 2,706 genes regulated by berberine in MCF-7 and MDA-MB-231 cells, respectively. Fene oncology (GO) analysis identified that many of the target genes were involved in regulation of the cell cycle, cell migration, apoptosis, and drug responses. To confirm the microarray data, qPCR analysis was conducted for 10 selected genes based on previously reported associations with breast cancer and GO analysis. In conclusion, berberine exhibits inhibitory effects on breast cancer cells proliferation, which is likely mediated by alteration of gene expression profiles.

The Effects of Lycopene on the Methylation of the GSTP1 Promoter and Global Methylation in Prostatic Cancer Cell Lines PC3 and LNCaP

DNA (cytosine-5-) methylation silencing of GSTP1 function occurs in prostate adenocarcinoma (PCa). Previous studies have shown that there is an inverse relationship between dietary lycopene intake and the risk of PCa. However, it is unknown whether lycopene reactivates the tumor suppressor gene glutathioneS-transferase-π (GSTP1) by demethylation of the hypermethylated CpGs that act to silence the GSTP1 promoter. Here, we demonstrated that lycopene treatment significantly decreased the methylation levels of the GSTP1 promoter and increased the mRNA and protein levels of GSTP1 in an androgen-independent PC-3 cell line. In contrast, lycopene treatment did not demethylate the GSTP1 promoter or increase GSTP1 expression in the androgen-dependent LNCaP cell line. DNA methyltransferase (DNMT) 3A protein levels were downregulated in PC-3 cells following lycopene treatment; however, DNMT1 and DNMT3B levels were unchanged. Furthermore, the long interspersed element (LINE-1) and short interspersed element ALU were not demethylated when treated by lycopene. In LNCaP cells, lycopene treatment did not affect any detected DNMT protein expression, and the methylation levels of LINE-1 and ALU were decreased. These results indicated that the protective effect of lycopene on the prostate is different between androgen-dependent and androgen-independent derived PCa cells. Further, in vivo studies should be conducted to confirm these promising results and to evaluate the potential role of lycopene in the protection of the prostate.

Different involvement of promoter methylation in the expression of organic cation/carnitine transporter 2 (OCTN2) in cancer cell lines

Organic cation/carnitine transporter 2 (OCTN2) is responsible for the cellular uptake of the antineoplastic agent, oxaliplatin. Epigenetic modification is a possible mechanism of altered drug-transporter expression in cancers, leading to altered efficacy of chemotherapeutic drugs. However, the mechanisms governing OCTN2 regulation are not completely understood. In this study, the low levels of OCTN2 in HepG2 and LS174T cells were elevated by the demethylating reagent, decitabine (DCA). To further reveal the epigenetic mechanism of down-regulation of OCTN2, we found that Region-1 within the OCTN2 promoter (spanning −354 to +85) was a determinant of OCTN2 expression in a luciferase reporter assay. Moreover, methylation-specific PCR (MSP) and bisulfite genomic sequencing showed that the degree of individual methylated CpG sites within this region was inversely correlated with the levels of OCTN2 in different cancer cells. Application of DCA to HepG2 and LS174T cells reversed the hypermethylation status of the OCTN2 promoter and increased OCTN2 expression, enhancing cellular uptake of oxaliplatin. Thus, we identified that promoter methylation is responsible for epigenetic down-regulation of OCTN2 in HepG2 and LS174T cells. Given the essential role of OCTN2 in cancer cell uptake of chemotherapeutics, and thus treatment efficacy, pretreatment with a demethylating reagent is a possible strategy for optimizing pharmacotherapies against cancers.

Polymorphism of ORM1 is associated with the pharmacokinetics of telmisartan

BACKGROUND

The pharmacokinetics (PKs) and pharmacodynamics (PDs) of telmisartan varies among the individuals, and the main causes remain unknown. The aim of this study was to evaluate the impact of ORM1, as well as ABCC2, ABCB1, ABCG2 and SLCO1B3 polymorphisms, on the disposition of the drug and BP change after taking 40 mg telmisartan in 48 healthy Chinese males.

METHOD

A total of 48 healthy males were included in this trial. Every volunteer ingested a single dose of 40 mg telmisartan, and the plasma drug concentration and blood pressure (BP) were measured up to 48 h.

RESULT

In this study, the area under the plasma concentration-time curve (AUC) in the heterozygotes of ORM1 113AG was higher than that in the wild-type homozygotes, AUC(0-48) (113AA vs. 113AG, 1,549.18±859.84 ng·h/ml vs. 2,313.54±1,257.71 ng·h/ml, P = 0.033), AUC(0-∞) (113AA vs. 113AG, 1,753.13±1,060.60 ng·h/ml vs. 2,686.90±1,401.87 ng·h/ml, P = 0.016), and the change(%) of the diastolic blood pressure (DBP) from the baseline BP value also showed a significant difference between the ORM1 113AG and 113AA genotypes at 5 h after taking telmisartan (P = 0.026). This study also showed that the allele of ABCC2 C3972T would affected the disposition of telmsiartan and the DBP change significantly after taking the drug. However, the common SNPs of ABCG2 C421, ABCB1 C3435T, and SLCO1B3 T334G showed no impacts on the PKs of telmisartan or BP change(%) in our trial.

CONCLUSION

The ORM1 A113G polymorphism was associated with the PKs variability after taking telmsiartan, as well as ABCC2 C3972T. The heterozygotes of ORM1 113AG showed a larger AUC and a notable BP change(%) from the baseline compared with the wild-type.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR-TNC-10000898.

Inhibition of the organic anion-transporting polypeptide 1B1 by quercetin: an in vitro and in vivo assessment

AIM

To investigate the effect of quercetin on organic anion transporting polypeptide 1B1 (OATP1B1) activities in vitro and on the pharmacokinetics of pravastatin, a typical substrate for OATP1B1 in healthy Chinese-Han male subjects.

METHODS

Using human embryonic kidney 293 (HEK293) cells stably expressing OATP1B1, we observed the effect of quercetin on OATP1B1-mediated uptake of estrone-3-sulphate (E3S) and pravastatin. The influence of quercetin on the pharmacokinetics of pravastatin was measured in 16 healthy Chinese-Han male volunteers receiving a single dose of pravastatin (40 mg orally) after co-administration of placebo or 500 mg quercetin capsules (once daily orally for 14 days).

RESULTS

Quercetin competitively inhibited OATP1B1-mediated E3S uptake with a K(i) value of 17.9 ± 4.6 µm and also inhibited OATP1B1-mediated pravastatin uptake in a concentration dependent manner (IC(50) , 15.9 ± 1.4 µm). In healthy Chinese-Han male subjects, quercetin increased the pravastatin area under the plasma concentration - time curve (AUC(0,10 h) and the peak plasma drug concentration (C(max)) to 24% (95% CI 15, 32%, P < 0.001) and 31% (95% CI 20, 42%, P < 0.001), respectively. After administration of quercetin, the elimination half-life (t(1/2) ) of pravastatin was prolonged by 14% (95% CI 4, 24%, P = 0.027), with no change in the time to reach C(max) (t(max) ). Moreover, quercetin decreased the apparent clearance (CL/F) of pravastatin by 18% (95% CI 75, 89%, P < 0.001).

CONCLUSIONS

These findings suggest that quercetin inhibits the OATP1B1-mediated transport of E3S and pravastatin in vitro and also has a modest inhibitory influence on the pharmacokinetics of pravastatin in healthy Chinese-Han male volunteers. The effects of quercetin on other OATP1B1 substrate drugs deserve further investigation.

Involvement of the Snk-SPAR pathway in glutamate-induced excitotoxicity in cultured hippocampal neurons

The serum-induced kinase (Snk)-spine-associated Rap GTPase-activating protein (SPAR) signaling pathway is reported as a new molecular mechanism in activity-dependent remodeling of synapses. However, the relationship between Snk-SPAR pathway and glutamate-induced excitotoxicity is not well understood. We report here that in cultured hippocampal neurons, glutamate stimulation induces the activation of Snk-SPAR pathway, and leads to a loss of mature dendritic spines. The time-dependent changes in Snk and SPAR expression after glutamate exposure are also elucidated. Furthermore, the activation of Snk-SPAR pathway induced by glutamate treatment can be blocked by an NMDA receptor antagonist, MK801. These results demonstrate that Snk-SPAR pathway may play a pivotal role in glutamate-induced excitotoxic damage in CNS through regulating the stability of synapse.

[Heat shock response induces resistance to hydrogen peroxide and increases synthesis of interleukin-6 in rat astrocyte in vitro]

Cell viability and cell membrane disruption of rat astrocyte after heat shock response (HSR) were assessed by the analysis of MTT reduction and lactate dehydrogenase (LDH) release. We studied whether HSR would modulate the susceptibility of astrocyte to H2O2-induced oxidative stress. Cell viability was assessed by reduction of MTT. HSR in 43 degrees C water bath for 30 min decreased H2O2 toxicity (P < 0.01) to astrocyte. HSR induced decrease in H2O2 (50 mumol/L) toxicity was also shown by the reduction in the release of LDH, which was a marker of cell membrane disruption. The result also showed that prior to the incubation in 43 degrees C water bath for 30 min strongly increased IL-6 release 6 h (P < 0.05) after HSR. The above data suggest that the enhanced release of IL-6 from astrocyte may be one of the mechanisms underlying the cell protective effect induced by HSR.

Transient expression of virus-specific promoters in murine resident peritoneal macrophages

Monocyte-macrophages (MO), being non-permissive for most viruses, play an important role in resistance to virus infection. In order to establish the mechanism of abortive infection of murine resident peritoneal MO (ResPMO) by herpes simplex virus type 1 (HSV-1), it is desirable to transfect these cells with viral promoters linked to an assayable gene, for example, the bacterial chloramphenicol acetyl transferase (CAT) gene. This will facilitate studies designed to measure levels of promoter activation or repression in these specialized cells. Transient expression of CAT in ResPMO was achieved with DEAE-dextran, but not using either calcium phosphate precipitate or lipofectin. CAT expression driven by various virus-specific promoters was less efficient in ResPMO compared with Vero cells and approximately 50% of input plasmid DNA remained in Vero cells at 48 h post transfection, but only 9% was detectable in ResPMO. However, approximately 6% of ResPMO and 9% of Vero cells contained CAT-specific DNA at 24 h post transfection. In addition, 2% of cells of either cell type contained CAT-specific polypeptide at 48 h. This is therefore the first report that the non-replicating murine ResPMO can be transfected in vitro and more importantly, that these cells express the transfected gene products.

Impaired interleukin 1 and interleukin 2 production following in vitro abortive infection of murine spleen mononuclear cells by Semliki Forest virus

The effect of Semliki Forest virus (SFV) infection of murine spleen mononuclear cells was investigated in vitro. A small percentage of spleen macrophages expressed viral antigens, but no infectious virus particles were released, indicating an abortive-type infection. Wild-type SFV infected a higher percentage of macrophages than the attenuated, demyelinating mutant A7. The proliferation of spleen mononuclear cells under Con A stimulation was inhibited by the viral infection. The supernatant (SN) harvested from infected and Con A-stimulated spleen adherent cells could not stimulate thymocytes in an interleukin 1 (IL-1) assay and indomethacin treatment of infected cultures had no effect. The stimulatory effect of SN from noninfected cultures in the IL-1 assay was reduced when SN from infected cultures was added, suggesting the presence of an IL-1 inhibitor. Interleukin 2 (IL-2) production by splenocytes also decreased after viral infection, but exogenous IL-2 restored the response to Con A stimulation of infected spleen cells. This study demonstrates that abortive SFV infection of spleen macrophages has an immunosuppressive effect which may lead to an aberrant immune regulation.

Effect of viral infection on experimental allergic encephalomyelitis in mice

BALB/c mice were irradiated with 350 R and injected with mouse spinal cord homogenate (MSCH) in complete Freund's adjuvant. Only 15-30% of these animals developed signs of experimental allergic encephalomyelitis (EAE) at 21-28 days after inoculation. Intraperitoneal infection with the non-lethal A7 strain of Semliki forest virus (SFV) 7 days after sensitization reduced the mean appearance time of the EAE symptoms to 14 days and the number of animals with clinical EAE increased up to 70%. In contrast, virus inoculation 10 days before induction of EAE decreased significantly the incidence of clinical EAE in both BALB/c and SJL mice. Demyelination with increased cellularity, presence of macrophages, stripping of myelin from the axons and sparing of oligodendrocytes was observed in spinal cords of animals at days 13-16 after induction of EAE and subsequent virus infection. No demyelination was seen in specimens taken at the same time from mice inoculated with MSCH or SFV alone. Combined MSCH and virus inoculations induced changes in the general immune response which may be one of the major reasons for the increase or decrease in demyelination in this model.