Phosphoserine phosphatase as a prognostic biomarker in patients with gastric cancer and its potential association with immune cells.

BACKGROUND: Because of dismal prognosis in gastric cancer, identifying relevant prognostic factors is necessary. Phosphoserine phosphatase (PSPH) exhibits different expression patterns in many cancers and has been reported to affect the prognosis of patients with cancer. In this study, we examined the prognostic role of metabolic gene PSPH in gastric cancer based on the TCGA dataset and our hospital-based cohort cases. METHODS: We collected and analysed RNA-seq data of Pan-cancer and gastric cancer in the TCGA dataset and PSPH expression data obtained from immunohistochemical analysis of 243 patients with gastric cancer from Sun Yat-sen University cancer center. Further, Kaplan-Meier survival analysis and Cox analysis were used to assess the effect of PSPH on prognosis. The ESTIMATE and Cibersort algorithms were used to elucidate the relationship between PSPH and the abundance of immune cells using the TCGA dataset. RESULTS: We observed that PSPH expression displayed considerably high in gastric cancer and it was significantly associated with inferior prognosis (P = 0.043). Surprisingly, there was a significant relationship between lower immune scores and high expression of PSPH (P < 0.05). Furthermore, patients with a low amount of immune cells exhibited poor prognosis (P = 0.046). The expression of PSPH significantly increased in activated memory CD4 T cells, resting NK cells and M0 macrophages (P = 0.037, < 0.001, and 0.005, respectively). CONCLUSIONS: This study highlighted that PSPH influences the prognosis of patients with gastric cancer, and this is associated with the infiltration of tumour immune cells, indicating that PSPH may be a new immune-related target for treating gastric cancer.

NRSF deficiency leads to abnormal postnatal development of dentate gyrus and impairment of progenitors in subgranular zone of hippocampus.

Neuron-restrictive silencing factor (NRSF) is a zinc-finger transcription factor that regulates expression of a diverse set of genes. However, NRSF function in brain development still remains elusive. In the present study, we generated NRSF-conditional knockout (NRSF-cKO) mice by hGFAP-Cre/loxp system to study the effect of NRSF deficiency on brain development. Results showed that NRSF conditional knockout caused a smaller hippocampus and a thinner granule cell layer (GCL) in mice. Moreover, the reduction and disarrangement of GFAP+ cells in subgranular zone (SGZ) of NRSF-cKO mice was accompanied with the decreased number of premature neurons, neural stem cells (NSCs) and neural progenitor cells (NPCs), as well as compromising the majority of mitotically active cells. The analysis of postnatal development of hippocampus indicated the existence of an abnormality at postnatal day (P) 8, rather than at P1, in NRSF-cKO mice, although the densities of Ki67+ cells with mitotic ability in dentate gyrus were relatively unaffected at P1 and P8. Meanwhile, NRSF deficiency led to abnormal organization of SGZ at P8 during postnatal development. RNA-Seq analysis revealed 79 deregulated genes in hippocampus of NRSF-cKO mice at P8, which were involved in p53 signal transduction, neuron migration and negative regulation of cell proliferation, etc. The deregulation of p53 pathway in NRSF-cKO mice at P1 and P8 was evidenced, of which p21/Cdkn1a was accumulated in a portion of NSCs and NPCs in hippocampus during postnatal development. Together, these results, for the first time, revealed that NRSF could significantly influence the postnatal development of hippocampus, especially the formation of SGZ.

Plasma SGIP1 methylation in diagnosis and prognosis prediction in hepatocellular carcinoma.

Aberrant methylation of some genes can serve as promising biomarkers in hepatocellular carcinoma (HCC). This study aimed to investigate the diagnostic and prognostic value of plasma SGIP1 methylation in HCC. The study included a total of 269 subjects, of which 129 were with HCC, 45 with liver cirrhosis (LC), 45 with chronic hepatitis B (CHB), and 50 were healthy controls (HCs). The aberrant methylation was detected by quantitative methylation-specific polymerase chain reaction (qMSP). The area under the curve (AUC) was 0.872 in distinguishing HCC from HCs, with a sensitivity of 85.3% and a specificity of 88%. The AUC was 0.728, when it distinguished HCC from CHB, with a sensitivity of 43.4% and a specificity of 97.8%. The AUC was 0.728 in distinguishing HCC from LC, with a sensitivity of 43.4% and a specificity of 97.8%. Elevated levels of SGIP1 methylation in HCC patients showed poorer overall survival (OS), progression-free survival (PFS), and metastasis-free survival (MFS) than those with low levels (Kaplan-Meier method and the log-rank test, p<0.05). SGIP1 methylation in different study groups demonstrated different sensitivities. SGIP1 methylation detection in the plasma may serve as a non-invasive diagnostic and prognostic biomarker for HCC.

[Localization and expression pattern of MDM2 in axon initial segments of neuron in rodent brain].

To investigate the murine double minute 2 (MDM2) localization and expression pattern in brain, immunohistochemistry, immunofluorescent staining and immunoblotting methods were used to analyze it in brains of Kunming mice during postnatal development, in brains of adult SD rats and in primarily cultured neurons. The distribution of MDM2 and markers of axon initial segment (AIS) was analyzed by double immunolabeling. In addition, Nutlin-3, a MDM2 antagonist, was injected into hippocampus to analyze the effect on the distribution of MDM2 and AIS protein Nav1.6 in AIS. The results showed that the dynamic expression patterns of MDM2 protein in cerebral cortex and hippocampus of Kunming mice after birth were different. However, it was similar that MDM2 was gradually enriched to AIS during postnatal development, especially after postnatal day 7. The MDM2 in AIS was also observed in different brain regions of adult SD rat brain and in primarily cultured neurons, where MDM2 was colocalized with AIS markers such as AnkG and Nav1.6. In addition, hippocampal injection of Nutlin-3 could induce the loss of the characteristic distribution of MDM2 in AIS. Moreover, Nutlin-3 not only caused a decrease of Nav1.6 distributing in AIS, but also disrupted the polarized distribution of MAP2 in neurons. These results indicate that MDM2 can be enriched at the AIS of adult rodent brain, which might play a role in regulation of the maintenance of AIS function and neuronal polarity.

Changes in inflammatory markers and efficacy analysis of continuous subcutaneous insulin infusion in senior patients with type 2 diabetes mellitus hospitalized with community-acquired pneumonia: a randomized controlled trial.

OBJECTIVE: The purpose of this study is to analyze the changes in inflammatory markers and efficacy in the treatment of senior patients with type 2 diabetes mellitus (T2DM) and community-acquired pneumonia with continuous subcutaneous insulin infusion (CSII). METHODS: A total of 105 senior patients with T2DM and community-acquired pneumonia, were randomly divided into two groups, viz., treatment group and control group-52 patients in the treatment group were treated with CSII, and 53 patients in the control group with multiple daily insulin injections (MDI). The changes in fasting blood glucose, postprandial blood glucose, total number of white blood cells, neutrophils, percentage of neutrophils, lymphocytes, percentage of lymphocytes, C-reactive protein, serum amyloid A, procalcitonin, interleukin-6 indexes, and the improvement in clinical outcome between the two groups were compared on the 5th and the 10th day of treatment. RESULTS: In the treatment group, there were 52 patients with an average age of (73.7 ± 8.5) years, which included 28 males and 24 females. In the control group, there were 53 patients, with 27 males and 26 females, with an average age of (74.8 ± 8.8) years. On the 5th and the 10th day of the treatment, the fasting blood glucose, postprandial blood glucose, total number of white blood cells, neutrophils, percentage of neutrophils, lymphocytes, percentage of lymphocytes, C-reactive protein, serum amyloid A, procalcitonin and interleukin-6 of the treatment group were better than that of the control group (P < 0.05). The use of CSII was associated with a higher probability of a prompt recovery (P < 0.05). CONCLUSION: The administration of CSII in the treatment of senior patients with T2DM and community-acquired pneumonia can effectively control fasting and postprandial blood glucose, significantly reduce the levels of inflammatory markers, and improve infection treatment efficacy.

Methylated ctDNA predicts early recurrence risk in patients undergoing resection of initially unresectable colorectal cancer liver metastases.

Background: Patients with initially unresectable colorectal cancer liver metastases (IU-CRLM) might benefit from using an effective systemic treatment followed by resection of liver metastases but the curative success rate is quite low. Indeed, nearly one-third of patients exhibit early recurrence within the first 6 months after surgery, and these individuals often have poor overall survival. Objectives: This study aims to clarify the application value of serial circulating tumor DNA (ctDNA) analysis in predicting the clinical outcome of IU-CRLM patients following liver metastasectomy. Design: A retrospective study was conducted on a cohort of patients with IU-CRLM between February 2018 and April 2021. Methods: Plasma samples at different time points during CRLM treatment [baseline (BL), preoperation (PRE), postoperation (POST), end-of-treatment (EOT), and progressive disease (PD)] were retrospectively collected from patients with initially unresectable CRLM enrolled at the Sun Yat-sen University Cancer Center. Dynamic changes of SEPTIN 9 (SEPT9) and Neuropeptide Y (NPY) methylated circulating tumor DNA (MetctDNA) levels in serial plasma samples were detected using droplet-digital PCR (ddPCR). Results: SEPT9 and NPY genes were hypermethylated in colon cancer cell lines and tissues while no difference was observed between primary and metastatic tumors. Patients with MetctDNA positive at POST or EOT had significantly lower recurrence-free survival (RFS) compared to patients with MetctDNA negative at these time points [POST: Hazard ratio (HR) 9.44, 95% confidence interval (CI) 5.15-17.30, p < 0.001; EOT: HR 11.48, 95% CI 3.27-40.31, p < 0.001]. Multivariate analysis demonstrated that POST (OR 33.96, 95% CI 4.03-286.10, p = 0.001) and EOT (OR 18.36, 95% CI 1.14-295.71, p = 0.04) MetctDNA was an independent risk factor for early recurrence. Time-dependent receiver operating characteristic curve (T-ROC) analysis revealed that area under the curve (AUC) value was greatest at the relapse time point of 6 months post-intervention, with POST-AUC and EOT-AUC values of 0.74 (95% CI 0.66-0.81) and 0.73 (95% CI 0.53-0.94), respectively. Serial MetctDNA analysis showed that RFS was significantly lower in patients with no MetctDNA clearance compared with those with MetctDNA clearance (HR 26.05, 95% CI 4.92-137.81, p < 0.001). Conclusion: Our study confirmed that serial ctDNA analysis of NPY and SEPT9 gene methylation could effectively predict early recurrence in IU-CRLM patients, especially at POST and EOT.

Adipose-derived mesenchymal stem cell exosomes ameliorate spinal cord injury in rats by activating the Nrf2/HO-1 pathway and regulating microglial polarization.

As of now, there are no satisfactory treatments for spinal cord injury (SCI), so new therapeutic approaches are necessary to be explored. Adipose-derived mesenchymal stem cell exosomes (ADMSC-Exo), delightfully, show remarkable therapeutic effects. Therefore, we try to investigate the effects and mechanisms of ADMSC-Exo on SCI, as well as to provide novel approaches for the treatment of SCI. Adipose-derived mesenchymal stem cells (ADMSC) were isolated from rats and then exosomes (Exo) were extracted from the cells. The extracted Exo were identified by flow cytometry, transmission electron microscopy and nanoparticle tracking analysis (NTA). Then, the SCI rat model was established by the spinal cord impactor and injected with 200 µl PBS or Exo into their tail veins at 30 min, 24 h, and 48 h after surgery. The rats in the Control group and Exo group only exposed the spine. Motor function recovery was assessed on days 0, 7, 14, 21, and 28; histopathological changes and apoptosis levels in spinal cord tissues were observed by HE staining and TUNEL staining; the levels of inflammatory cytokines TNF-a, IL-6, and MCP-1 in spinal cord tissues were measured by ELISA; the expression levels of iNOS, IL-12, Arg1, and Mrc1 in spinal cord tissues were detected by qRT-PCR; and Nrf2, HO-1, and NQO1 protein expression in spinal cord tissues were detected by Western blot. ADMSC-Exo were successfully isolated and identified. ADMSC-Exo significantly relieved SCI and promoted motor function recovery in SCI rats. Moreover, ADMSC-Exo inhibited the expression of both inflammatory factors in the spinal cord tissues and M1 microglia, promoted the expression of M2 microglia, and activated the Nrf2/HO-1 pathway. Altogether, ADMSC-Exo can not only ameliorate SCI, but also promote the motor function recovery of rats. And the mechanism of ADMSC-Exo improving SCI may be achieved by activating Nrf2/HO-1 pathway and microglial polarization.

Response to programmed cell death protein 1 antibody in patients with Epstein-Barr virus-associated intrahepatic cholangiocarcinoma.

AIM: Epstein-Barr virus-associated intrahepatic cholangiocarcinoma (EBVaICC) has a distinct genomic profile and increased CD3+ and CD8+ T cells infiltration. However, the efficacy of immunotherapy in EBVaICC remains largely unknown. This study aimed to assess the efficacy of programmed cell death protein 1 (PD-1) antibody therapy in EBVaICC. METHODS: Patients with metastatic biliary tract cancer (BTC) diagnosed at Sun Yat-sen University Cancer Center from January 2016 to December 2021 were identified. In situ hybridisation was performed to detect EBV. Overall survival (OS) and progression-free survival (PFS) were measured. RESULTS: A total of 698 patients with metastatic BTC were identified, of whom 39 (5.6%) had EBVaICC. Among the 136 patients who were not administered PD-1 antibody, the OS was similar between patients with EBVaICC and EBV-negative ICC (median OS 12.5 versus 9.5 months, respectively; P = 0.692). For the 205 patients who were administered PD-1 antibody, patients with EBVaICC had significantly longer OS than patients with EBV-negative ICC (median OS 24.9 versus 11.9 months, respectively; P = 0.004). Seventeen patients with EBVaICC were administered PD-1 antibody. Eight patients (47%) achieved a partial response, and 17 patients achieved disease control. The median PFS was 17.5 months. CONCLUSIONS: This study identified a clinically actionable subset of patients with EBVaICC with a promising response to the PD-1 antibody.

Targeted demethylation of the CDO1 promoter based on CRISPR system inhibits the malignant potential of breast cancer cells.

BACKGROUND: Cysteine dioxygenase 1 (CDO1) is frequently methylated, and its expression is decreased in many human cancers including breast cancer (BC). However, the functional and mechanistic aspects of CDO1 inactivation in BC are poorly understood, and the diagnostic significance of serum CDO1 methylation remains unclear. METHODS: We performed bioinformatics analysis of publicly available databases and employed MassARRAY EpiTYPER methylation sequencing technology to identify differentially methylated sites in the CDO1 promoter of BC tissues compared to normal adjacent tissues (NATs). Subsequently, we developed a MethyLight assay using specific primers and probes for these CpG sites to detect the percentage of methylated reference (PMR) of the CDO1 promoter. Furthermore, both LentiCRISPR/dCas9-Tet1CD-based CDO1-targeted demethylation system and CDO1 overexpression strategy were utilized to detect the function and underlying mechanism of CDO1 in BC. Finally, the early diagnostic value of CDO1 as a methylation biomarker in BC serum was evaluated. RESULTS: CDO1 promoter was hypermethylated in BC tissues, which was related to poor prognosis (p < .05). The CRISPR/dCas9-based targeted demethylation system significantly reduced the PMR of CDO1 promotor and increased CDO1 expression in BC cells. Consequently, this leads to suppression of cell proliferation, migration and invasion. Additionally, we found that CDO1 exerted a tumour suppressor effect by inhibiting the cell cycle, promoting cell apoptosis and ferroptosis. Furthermore, we employed the MethyLight to detect CDO1 PMR in BC serum, and we discovered that serum CDO1 methylation was an effective non-invasive biomarker for early diagnosis of BC. CONCLUSIONS: CDO1 is hypermethylated and acts as a tumour suppressor gene in BC. Epigenetic editing of abnormal CDO1 methylation could have a crucial role in the clinical treatment and prognosis of BC. Additionally, serum CDO1 methylation holds promise as a valuable biomarker for the early diagnosis and management of BC.

[Levels of serum acylation-stimulating protein and C3 in children with primary nephrotic syndrome].

OBJECTIVE: To study serum acylation-stimulating protein (ASP) and complement 3 (C3) levels and their relationship with blood lipids in children with primary nephrotic syndrome (PNS). METHODS: Blood samples were obtained from 35 PNS children with proteinuria, 25 children with PNS at remission and 35 body mass index-matched healthy children (control group). Fasting serum ASP, C3, albumin and blood lipids were measured. RESULTS: The serum ASP levels in the proteinuria group (101 ± 22 nmol/L) were significantly higher than those in the remission group (32 ± 8 nmol/L) and the control group (33 ± 8 nmol/L) (P<0.01). Serum C3 levels were not significantly different among the three groups. The serum concentrations of total cholesterol, triglyceride, low density lipoprotein and apolipoprotein B increased, in contrast, serum albumin level decreased significantly in the proteinuria group when compared with the remission and the control groups. Serum ASP levels were positively correlated with serum C3 (r=0.661; P<0.05) and triglyceride levels (r=0.354; P<0.05), whereas serum C3 levels were not correlated with serum triglyceride levels (r=0.319, P>0.05). CONCLUSIONS: The increased serum ASP level may be associated with a complemental mechanism against hyperlipidemia in children with PNS.

[Microscope assisted anterior cervical discectomy and fusion for the treatment of single segment cervical spondylotic myelopathy].

OBJECTIVE: To compare the efficacy of microscope assisted anterior cervical discectomy and fusion with conventional surgical approach in the treatment of single-segment cervical spondylotic myelopathy. METHODS: The clinical data of 89 patients with single-segment cervical spondylotic myelopathy treated from March 2015 to March 2019 were retrospectively analyzed. There were 55 males and 34 females, with an average of (52.00±11.36) years old. Among the patients, 34 cases were treated with conventional anterior cervical discectomy with fusion (conventional group), including C3,4 in 3 cases, C4,5 in 10 cases, C5,6 in 15 cases, C6,7 in 6 cases; 55 cases were treated with microscopeassisted anterior cervical discectomy with fusion (microscope group), including C3,4 in 5 cases, C4,5 in 23 cases, C5,6 in 20 cases, C6,7 in 7 cases. Operative time, intraoperative blood loss, hospital stay and complications were compared between two groups. Clinical efficacy was assessed by visual analogue scale(VAS), Japanese Orthopaedics Association (JOA) scores, Oswestry Disability Index(ODI) during follow-up period (postoperative 1 week, 3 months and 12 months). RESULTS: Intraoperative blood loss and hospital stay in microscope group were less than those in conventional group (P<0.05), and operative time of conventional group was shorter than that of microscope group (P<0.05). Postoperative JOA, VAS and ODI were significantly improved in each groups (P<0.05). VAS scores of microscope group were better than that of conventional group at 1 week and 3 months after operation(P<0.05), but there was no statistically significant difference between two groups at 12 months after operation (P>0.05). JOA scores of microscope group at each postoperative follow-up were better than that of conventional group (P<0.05). ODI scores of microscope group at 3, 12 months after operation were better than that of conventional group (P<0.05). CONCLUSION: Both methods can achieve satisfactory effect in treating single-segment cervical spondylotic myelopathy. However, microscope-assisted anterior cervical discectomy and fusion has advantages of clear vision, less bleeding and fewer intraoperative complications.

Mutational landscape of primary pulmonary salivary gland-type tumors through targeted next-generation sequencing.

OBJECTIVES: Primary pulmonary salivary gland-type tumors (PSGTs) mainly comprise of mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC), which are rare and molecularly poorly understood. This study aimed to profile the molecular alterations of PSGTs via targeted next-generation sequencing (NGS). MATERIAL AND METHODS: Immunohistochemistry was used to screen PSGTs in 32 patients and MAML2 and MYB rearrangements were detected using fluorescence in situ hybridization. 1021-Genepanel of targeted NGS was conducted to profile genomic mutations in all the PSGT patients. RESULTS: Among the 32 patients, 25 had MEC and 7 had ACC. MAML2 and MYB rearrangements were detected in 80.0% (20/25) of the MEC and 71.4% (5/7) of the ACC patients. Among the MEC patients, 10 (40.0%) had ≥1 mutation, and 6 of them had 11 isolated mutations with abundance >5%, namely NFE2L2, MYOD1, INPP4B, CCND2, SNTG1, HSPD1, TGFBR1, RBM10, NOTCH4, ASXL1, and PTPRD mutations. The remaining 4 patients had 9 mutations with abundance <5%, namely KMT2A, PDCD11, FLT1, BRCA2, APC, SLX4, FOXP1, FGFR1, and HRAS mutations. All the ACC patients had mutations, which were enriched in 5 pathways including the PI3K and NOTCH pathways, chromatin and cytoskeleton remodeling, and DNA damage. These results explain PSGTs harbor distinct driver features of MAML2 or MYB rearrangement, accompanied with wide mutational diversity with very low rate of somatic mutation. Several important pathways, including the NOTCH and PI3K pathways, and chromatin remodeling could be targeted to improve the survival in patients with ACC.

Overexpression of F(0)F(1)-ATP synthase alpha suppresses mutant huntingtin aggregation and toxicity in vitro.

Huntington's disease (HD) and other polyglutamine (polyQ) neurodegenerative diseases are characterized by neuronal accumulation of the disease protein, suggesting that the cellular ability to handle abnormal proteins is compromised. As a multi-subunit protein localized in the mitochondria of eukaryotic cells, the F(0)F(1)-ATP synthase alpha belongs to the family of stress proteins HSP60. Currently, mounting evidences indicate F(0)F(1)-ATP synthase alpha may play a role in neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Recently, ATP synthase alpha was reported to have protective and therapeutic roles in primary cardiacmyocytes of iron-overloaded rats by lowering ROS production. However, little is understood about the role of ATP synthase alpha in cell death and neurodegeneration. Here, we demonstrate that overexpression of ATP synthase alpha suppresses huntingtin (htt) polyQ aggregation and toxicity in transfected SH-SY5Y cell lines. Overexpression of ATP synthase alpha is able to protect cell death caused by polyglutamine-expanded htt. Transient overexpression of ATP synthase alpha suppresses the aggregate formation by estimation of polyQ aggregation, Western blot analysis, and filter trap assay (FTA) in transfected SH-SY5Y cells. These results indicated that ATP synthase alpha has a strong inhibitory effect on polyglutamine aggregate formation and toxicity in vitro, and suggest a novel neuroprotective role of ATP synthase alpha.

Aging as a Precipitating Factor in Chronic Restraint Stress-Induced Tau Aggregation Pathology, and the Protective Effects of Rosmarinic Acid.

Stress is an important risk factor of Alzheimer's disease (AD). It has been evidenced that stress could induce tau phosphorylation and increase tau insolubility in brain; however, little is known about the interactional effect of stress with aging on tauopathy. Therefore, we explored the effects of aging on stress-induced tauopathy and the potential mechanism in mouse model of chronic restraint stress (CRS). Here we found that in general, the level of phosphorylated tau (P-tau) was higher in brain of middle-aged mice than that in adult mice under physiological conditions. CRS-induced tau phosphorylation and its insolubility were more prominent in middle-aged mice. The increase of AT8-labeled insoluble P-tau was dramatic in middle-aged mice, which was highly ubiquitinated but did not form PHF structures. The levels of chaperones were relatively lower in middle-aged mice brain; CRS further reduced the expression, especially for HDJ2/HSP40. CRS also suppressed the expression of Pin1, the peptidylprolyl cis/trans isomerase, in middle-aged mice but not in adult mice. Downregulation of HSP40 or Pin1 caused an increase of transfected extraneous tau in 293 cells. Rosmarinic acid (RA) could effectively suppress the elevation of P-tau and insoluble P-tau formation induced by CRS, and reversed the abnormal changes of chaperones and Pin1 particularly in middle-aged mice. Taken together, our findings provided evidence that aging could be a promoting factor in stress-induced tauopathy, which was relevant with malregulation of chaperones and Pin1, and RA might be a promising beneficial agent for stress-induced tauopathy.

Inhibitory influence of ginsenoside Rb(3) on activation of strychnine-sensitive glycine receptors in hippocampal neurons of rat.

Whole-cell patch-clamp technique was used to investigate the effect of ginsenoside Rb(3) (Rb(3)), an active constituent of Panax ginseng, on glycine receptor activity in immature hippocampal neurons, which were dissociated acutely from hippocampal CA(1) area in Sprague-Dawley rats aging 10-14 days using the method of enzyme digestion with mechanical dissociation. As a result, glycine elicited an inward current (I(gly)) in a concentration-dependent manner in approximately 86% of those isolated neurons tested. This current was strychnine-sensitive. Rb(3) itself did not elicit any membrane currents. However, coapplication of Rb(3) inhibited peak current of I(gly). This depressant effect of Rb(3) varied with its concentrations. At a concentration of 0.1 micromol/L, ginsenoside Rb(3) had the most significant inhibition, with a net reduction of 31% in average. Moreover, the inhibition of I(gly) by Rb(3) did not depend on the membrane potential. Rb(3) (0.1 micromol/L) presented inhibitory effect on I(gly) mainly at higher glycine concentrations (>100 micromol/L), and decreased maximal glycine efficacy. This effect was the same as that of a non-competitive antagonist of glycine receptors. Finally, we found that Rb(3) prolonged the time constant of activation of I(gly). It is therefore suggested that ginsenoside Rb(3), possibly as a non-competitive antagonist, could inhibit strychnine-sensitive glycine current at a dose-dependent manner in acutely dissociated hippocampal CA(1) neurons of young rats, and decrease of affinity of glycine to receptors and delay of receptor activation may be involved in this inhibition. Inhibitory effect of ginsenoside Rb(3) on I(gly) is possibly one of the bases of many pharmacological actions of Panax ginseng.

Association between XRCC1 polymorphisms and glioma risk among Chinese population.

The pathogenesis of glioma remains largely unknown now. It has been suggested that the X-ray cross-complementing group 1 (XRCC1) gene may influence the capacity to repair DNA damage leading to an increased gliomas susceptibility. This study aimed to evaluate the relationship between XRCC1 polymorphisms and glioma risk. Genotypes were assessed in 368 Chinese glioma patients and 346 healthy controls. XRCC1 Arg194Trp (rs1799782), Arg280His (rs25489) and Arg399Gln (rs25487) and three additional polymorphisms were directly sequenced. The frequency of Arg280His A allele was significant lower in glioma group than in healthy controls [9.6 vs 16%, OR=0.60 (0.46-0.80), P<0.001]; the frequencies of GA or AA genotypes were different in two groups (16.6 vs 22.8%, 1.3 vs 4.7%). The frequency of Arg399Gln A allele was significant higher in glioma group than in healthy controls [38.7 vs 30.1%, OR=1.29 (1.11-1.49), P=0.001]; the frequencies of GA or AA genotypes were different in two groups (45.4 vs 38.2%, 16 vs 10.9%). This study demonstrates that the rs25489 (Arg280His) and Arg399Gln (rs25487) polymorphisms in XRCC1 gene might influence the risk of developing glioma in Chinese population.

Upregulation of heme oxygenase-1 by acteoside through ERK and PI3 K/Akt pathway confer neuroprotection against beta-amyloid-induced neurotoxicity.

Our previous study has shown that acteoside, an antioxidative phenylethanoid glycoside, protect against beta-amyloid (Aß)-induced cytotoxicity in vitro. However, the precise protective mechanisms remains unclear. Heme oxygenase-1 (HO-1) is a crucial factor in the response to oxidative injury, protecting neurons against Aß-induced injury. In the present study we examined to determine whether acteoside upregulates HO-1 expression, and thereby protects PC12 cells against Aß-induced cell death. It was revealed that acteoside is an activator of Nrf2 and inducer of HO-1 expression. We showed that acteoside increased HO-1 expression in vitro and in vivo. Acteoside treatment resulted in nuclear translocation of the transcription factor NF-E2-related factor 2 (Nrf2). Acteoside activated both ERK and PI3 K/Akt, and treatments with the specific ERK inhibitor PD98059, the PI3 K inhibitor LY294002, and the specific Nrf2 siRNA suppressed the acteoside-induced HO-1 expression. The HO-1 inhibitor ZnPP, PD98059, and LY294002 markedly abolished the neuroprotective effect of acteoside against Aß-induced neurotoxicity. Taken together, these results demonstrate that acteoside is an activator of Nrf2 and inducer of HO-1 expression. We also showed that acteoside increased HO-1 expression through activation of ERK and PI3 K/Akt signal pathways in vitro. Upregulation of HO-1 by acteoside may involve in the neuroprotection against Aß-induced neurotoxicity.

Effect of neuronal excitotoxicity on Munc18-1 distribution in nuclei of rat hippocampal neuron and primary cultured neuron.

OBJECTIVE: Munc18-1 has an important role in neurotransmitter release, and controls every step in the exocytotic pathway in the central nervous system. In the present study, whether epileptic seizure causes a change of Munc18 localization in neuronal nuclei was analyzed. METHODS: Epilepsy models were established by injection of kainic acid (KA) solution into hippocampus of Sprague-Dawley (SD) rats or intraperitoneal injection of KA in Kunming mice. The hippocampal neurons were prepared from embryonic day 18 SD rats, and cultured in neurobasal medium, followed by treatment with glutamate for 3 h. Neuronal and glial nuclei of hippocampus were separated by sucrose density gradient centrifugation. The nucleus-enriched fractions were stained with 0.1% Cresyl Violet for morphological assay. Immunochemistry and immunoelectron microscopy with anti-Munc18-1 antibody were used to determine the nuclear localization of Munc18-1. Immunoblotting was used to detect the protein level of Munc18-1. RESULTS: The localization of Munc18-1 in nucleus of rat hippocampal neuron was confirmed by immunochemistry, immunoelectron microscopy, and immunoblotting detection of neuronal nucleus fraction. In animals receiving intrahippocampal or intraperitoneal injection of KA, immunostaining revealed that the expression of Munc18-1 decreased in pyramidal cell layer of CA regions, as well as in hilus and granular cell layer of dentate gyrus in hippocampus. Moreover, immunoblotting analysis showed that the expression level of Munc18-1 in nucleus fraction of hippocampus significantly decreased in KA-treated animals. The relationship between the change of Munc18-1 expression in neuronal nuclei and neuronal over-activation was also tested in primary cultured neurons. After treatment with 50 µmol/L glutamate acid for 3 h, Munc18-1 level was decreased in nucleus fraction and increased in cytoplasmic fraction of primary cultured neurons. CONCLUSION: These results suggest that excitatory stimulation can induce the distribution change of Munc18-1 in neuron, which may subsequently modulate neuronal functions in brain.

Astaxanthin upregulates heme oxygenase-1 expression through ERK1/2 pathway and its protective effect against beta-amyloid-induced cytotoxicity in SH-SY5Y cells.

Astaxanthin (ATX), the most abundant flavonoids in propolis, has been proven to exert neuroprotective property against glutamate-induced neurotoxicity and ischemia-reperfusion-induced apoptosis. Previous study have revealed that ATX can rescue PC12 cells from Aß(25-35)-induced apoptotic death. However, the mechanisms by which ATX mediates its therapeutic effects in vitro are unclear. In the present study, we explored the underlying mechanisms involved in the protective effects of ATX on the Aß(25-35)-induced cytotoxicity in SH-SY5Y cells. Pre-treatment with ATX for 4h significantly reduced the Aß(25-35)-induced viability loss, apoptotic rate and attenuated Aß-mediated ROS production. In addition, ATX inhibited Aß(25-35)-induced lowered membrane potential, decreased Bcl-2/Bax ratio. We also demonstrated that ATX could prevent the activation of p38MAPK kinase pathways induced by Aß. Moreover, we for the first time have revealed the ATX increased antioxidant enzyme heme oxygenase-1 (HO-1) expression in concentration-dependent and time-dependent manners, which were correlated with its protective effect against Aß(25-35)-induced injury. Because the inhibitor of HO-1 activity, ZnPP reversed the protective effect of ATX against Aß(25-35)-induced cell death. We also demonstrated that the specific ERK inhibitor, PD98059, concentration-dependently blocked on ATX-induced HO-1 expression, and meanwhile PD98059 reversed the protective effect of ATX against Aß25-35-induced cell death. Taken together, these findings suggest that astaxanthin can induce HO-1 expression through activation of ERK signal pathways, thereby protecting the SH-SY5Y cells from Aß(25-35)-induced oxidative cell death.

Glutamate enhances the surface distribution and release of Munc18 in cerebral cortical neurons.

OBJECTIVE: Munc18 is considered as an intracellular protein that plays an important role in exocytosis of neurotransmitters. Previous studies have demonstrated the presence of autoantibodies against Munc18 in a subgroup of Rasmussen's encephalitis patients. However, the machinery of Munc18 autoimmunity is still elusive. The present study was aimed to investigate Munc18 release from primary cultured neurons, Munc18 distribution on the outer plasma membrane of neurons, and the neurotoxicity of Munc18 antibody. METHODS: The cerebral cortical neurons from embryonic day 17 Sprague-Dawley rats were prepared and cultured in neurobasal medium. The proteins in culture medium were precipitated with 10 % trichloroacetic acid, and analyzed by immunoblotting. The proteins on neuronal surface were biotinylated with EZ-Link-sulfo-NHS-LC-Biotin, and collected with avidin-conjugated agarose beads followed by immunoblotting analysis. For cell surface immunofluorescent staining, the living neurons were labeled with anti-Munc18 antibody at 4 degrees C. Neuronal injury was assessed by lactate dehydrogenase(LDH) release. RESULTS: Munc18 was detected in culture medium by immunoblotting analysis. After treatment with 50 micromol/L glutamate for 1 h, Munc18 content in medium was increased. Meanwhile, beta-actin and syntaxin1 were not detected in culture medium, and LDH release was not significantly increased. Moreover, glutamate enhanced Munc18 distribution on outer plasma membrane. Living neuron staining also demonstrated the localization of Munc18 on neuronal surface after glutamate treatment, especially at contacting regions between neurons. Glutamate-induced increase of surface Munc18 distribution was suppressed by NMDA receptor antagonist MK801, but not by AMPA receptor antagonist NBQX. Moreover, compared with c-Fos antibody, Munc18 antibody could induce neuronal injury, when culture medium contained the components of serum. CONCLUSION: A portion of Munc18 can be released from neurons or distributed on neuronal surface, which can be enhanced by glutamate treatment via activation of NMDA receptors. Besides, Munc18 antibody-induced neuronal injury depends on the serum components.