Surface expression and function of Cav3.2 T-type calcium channels are controlled by asparagine-linked glycosylation

Low-voltage-activated T-type calcium channels play important roles in neuronal physiology where they control cellular excitability and synaptic transmission. Alteration in T-type channel expression has been linked to various pathophysiological conditions such as pain arising from diabetic neuropathy. In the present study, we looked at the role of asparagine (N)-linked glycosylation on human Ca_v3.2 T-type channel expression and function. Manipulation of N-glycans on cells expressing a recombinant Ca_v3.2 channel revealed that N-linked glycosylation is critical for proper functional expression of the channel. Using site-directed mutagenesis to disrupt the canonical N-linked glycosylation sites of Ca_v3.2 channel, we show that glycosylation at asparagine N192 is critical for channel expression at the surface, whereas glycosylation at asparagine N1466 controls channel activity. Moreover, we demonstrate that N-linked glycosylation of Ca_v3.2 not only controls surface expression and activity of the channel but also underlies glucose-dependent potentiation of T-type Ca²⁺ current. Our data suggest that N-linked glycosylation of T-type channels may play an important role in aberrant upregulation of T-type channel activity in response to glucose elevations.     

Predicting Colonoscopy Screening Behavior and Future Screening Intentions for African Americans Older than 50 Years

Abstract

African Americans experience a disproportionate burden of morbidity and mortality from colorectal cancer, which may be due to low adherence to screening recommendations. Previous studies have found relationships between decision-making factors and screening behavior, but few have looked at both cognitive and affective factors or within a specifically African American sample. To better understand determinants that drive screening behavior, this study examines affective, cognitive, and social variables as predictors of colonoscopy in an age-eligible African American population. Participants completed surveys assessing affective associations with colonoscopy, perceived benefits and barriers, self-efficacy, knowledge, fear of colonoscopy, perceived risk, and colorectal cancer worry and fear. Regression analysis was used to model decision-making constructs as predictors of screening behavior/intentions. Affective, cognitive, and health care experience variables predicted colonoscopy completion and intentions. Provider-level factors and previous cancer screenings predicted prior screening only, but not intentions. Affective and cognitive components of perceived risk were associated with decreased likelihood of colonoscopy behavior, but increased likelihood of colonoscopy intentions. These findings suggest that colonoscopy decision making involves a complex array of both cognitive and affective determinants. This work extends our knowledge of colorectal cancer screening decision making by evaluating the effects of these multiple determinants on screening behavior in an African American sample. Future work exploring the interplay of affect and cognitions as influences on colonoscopy decision making and how health care experiences may moderate this effect is needed to develop effective intervention approaches and reduce screening disparities.     

STYK1基因在前列腺癌中的表达及意义

目的 研究STYK1基因在前列腺癌中的表达水平,探索STYK1在前列腺癌发病中的作用.方法 利用"UALCAN"等数据库分析STYK1基因在前列腺癌中的表达及生物学功能;收集67例前列腺癌组织样本,实时定量PCR法检测STYK1基因的表达水平,统计分析STYK1基因表达与临床病理特征的关系;慢病毒转染法构建STYK1低表达的LNCaP细胞系,CCK8法绘制细胞生长曲线,流式细胞仪检测细胞周期.结果 生物信息学分析显示STYK1基因在前列腺癌中特异性高表达,与AR、PSA、PSMA、PCA3基因具有显著的表达相关性,功能富集分析提示其参与了多种细胞代谢过程.实时定量PCR检测显示前列腺癌组织中STYK1基因的表达水平较癌旁组织显著升高,与患者的TNM分期、术前PSA水平显著相关(P<0.05).以STYK1表达水平诊断前列腺癌的ROC曲线下面积为0.925(P<0.05).生长曲线和流式细胞周期检测证实下调STYK1基因表达后能够抑制LNCaP细胞的增殖能力.结论 STYK1基因的表达水平在前列腺癌组织中特异性升高,具有潜在的诊断价值,并影响前列腺癌细胞的增殖过程.     

Baicalein reduces lipopolysaccharide-induced inflammation via suppressing JAK/STATs activation and ROS production

Objective

To investigate the precise molecular mechanisms by which baicalein exerts beneficial biochemical activities in RAW264.7 macrophages treated with LPS.

Materials and methods

RAW264.7 cells were cultured in the absence or presence of baicalein together with or without LPS. iNOS and COX-2 expression were measured by western blot and RT-PCR analyses. TNF-α, IL-1β, and IL-6 were determined by using double-antibody sandwich ELISA. Phosphorylations of JAK1 and JAK2, and of STAT1 and STAT3 were detected by western blotting. Nuclear translocation of STAT1 and STAT3 was visualized by confocal microscopy. ROS production was detected by ROS assay.

Results

Baicalein significantly reduced the phosphorylation of STAT1 and STAT3 and the phosphorylation of JAK1 and JAK2, but without affecting MAPKs phosphorylation in LPS-stimulated RAW264.7 cells. Baicalein suppressed the nuclear translocation of STAT1 and STAT3 and inhibited production of iNOS upon LPS-stimulation, resulting in the inhibition of releases of NO and pro-inflammatory cytokines such as IL-1β, IL-6, and TNF-α, in a dose-dependent manner. In addition, we found that baicalein reduced the LPS-induced accumulation of ROS, confirming that baicalein serves as an antioxidant.

Conclusions

Our results suggested that suppressing JAK/STATs activation and interfering with ROS production might contribute to the anti-inflammatory action of baicalein in macrophages.     

Role of anti-allergic agents on attenuating transfusion reactions in adults: A systematic review and meta-analysis

BackgroundAnti-allergic agents (e.g. dexamethasone, chlorpheniramine or promethazine) are commonly administered to patients prior to blood product transfusions. However, the use of these agents is largely experience-based instead of evidence-based. This meta-analysis aimed to explore the evidence behind using anti-allergic agents to attenuate transfusion reactions.Materials and MethodsThe Pubmed, EMBASE, Cochrane Library, Wanfang, Chinese National Knowledge Infrastructure (CNKI), and Chinese Biomedical literature (CMB) databases were all queried for related articles. Data from groups treated with and without anti-allergic agents were collected for meta-analysis using RevMan 5.3. Baseline characteristics and univariate statistics between groups were compared using SPSS 19.0.ResultsEight eligible articles (six case control studies and two randomized controlled trials, all with high risks of bias) were identified (22060 total cases). Administered anti-allergic agents in these studies only included dexamethasone, chlorpheniramine or promethazine. Baseline characteristics showed no significant age or gender differences between treatment or control groups. There were no significant differences between the pooled experimental or control groups (for each of the three medications) in terms of fever, pruritis, rash, airway spasm or overall transfusion reaction rates.ConclusionThere is no evidence that dexamethasone, chlorpheniramine or promethazine can prevent transfusion reactions. Avoiding the arbitrary use of such anti-allergic agents before blood transfusions may potentially avoid needless adverse drug reactions.