Phospholipase Cγ1 is required for pre‐TCR signal transduction and pre‐T cell development

Pre‐T cell receptor (TCR) signaling is required for pre‐T cell survival, proliferation, and differentiation from the CD4 and CD8 double negative (DN) to the double positive (DP) stage. However, the pre‐TCR signal transduction pathway is not fully understood and the signaling molecules involved have not been completely identified. Phospholipase Cγ (PLCγ) 1 is an important signaling molecule that generates two second messengers, diacylglycerol and inositol 1,4,5‐trisphosphate, that are important to mediate PKC activation and intracellular Ca²⁺ flux in many signaling pathways. Previously, we have shown that PLCγ1 is important for TCR‐mediated signaling, development and T‐cell activation, but the role of PLCγ1 in pre‐TCR signal transduction and pre‐T cell development is not known. In this study, we demonstrated that PLCγ1 expression level in pre‐T cells was comparable to that in mature T cells. Deletion of PLCγ1 prior to the pre‐TCR signaling stage partially blocked the DN3 to DN4 transition and reduced thymic cellularity. We also demonstrated that deletion of PLCγ1 impaired pre‐T cell proliferation without affecting cell survival. Further study showed that deficiency of PLCγ1 impaired pre‐TCR mediated Ca²⁺ flux and Erk activation. Thus our studies demonstrate that PLCγ1 is important for pre‐TCR mediated signal transduction and pre‐T cell development.     

Notch1在非小细胞肺癌中的研究

Notch1信号通路是许多细胞信号转导通路的交汇点,不仅在正常组织、细胞的分化、发育过程中起重要作用,而且与一些肿瘤的发生、发展相关,如食管癌、胃癌、宫颈癌、结肠癌、肺癌等.Notch1在非小细胞肺癌中的作用多样.了解Notch1和非小细胞肺癌的关系有利于进一步阐明非小细胞肺癌的发生机制,为非小细胞肺癌的治疗提供一个新的有希望的治疗靶点.     

BCG-CpG-DNA对支气管哮喘小鼠肺组织STAT4、STAT6表达的影响

目的 观察BCG-CpG-DNA干预对支气管哮喘(简称哮喘)小鼠信号转导和转录激活因子4(STAT4)、STAT6的影响,探讨其对小鼠哮喘的作用机制.方法 将30只BALB/c小鼠随机分为3组:正常对照组(A组)、哮喘模型组(B组)、BCG-CpG-DNA治疗组(C组).其中B、C组小鼠于第0天、第13天分别给予卵清白蛋白(OVA)和佐剂液态铝混悬液致敏,于第25天至第30天每天给予雾化OVA建立哮喘模型,C组于致敏后以BCG-CpG-DNA腹腔注射,A组以生理盐水代替OVA致敏和激发.所有动物于第31天处死,采用Western blot技术检测小鼠肺组织中STAT4、STAT6的蛋白表达水平.结果 与A组比较,B组STAT4、pSTAT4表达降低(P值均＜0.01),STAT6、pSTAT6的表达升高(P值均＜0.01);与B组比较,BCG-CpG-DNA治疗后小鼠哮喘症状和肺组织的炎症病理变化减轻,STAT4、pSTAT4表达增加,STAT6、pSTAT6表达降低,差异具有统计学意义(P值均＜0.01).结论 BCG-CpG-DNA可能通过抑制STAT6、促进STAT4的表达,调节Th1/Th2细胞因子平衡,从而起到抑制气道炎症的作用.     

脂肪因子补体C1q/肿瘤坏死因子相关蛋白3对胰岛素抵抗的3T3-L1脂肪细胞胰岛素信号通路影响的研究

目的 观察脂肪因子补体C1q/肿瘤坏死因子相关蛋白3(CTRP3)对IR的3T3-L1脂肪细胞胰岛素信号通路的影响. 方法 以软脂酸培养构建IR的3T3-L1脂肪细胞模型,分为对照组、CTRP3(10、50、250 ng/ml)干预组及CTRP3(250 ng/ml)+渥曼青霉素(Wortmannin)[磷脂酰肌醇3激酶(PI3K)抑制剂]干预组.以葡萄糖氧化酶法检测葡萄糖消耗量,以Western blot检测PI3K及蛋白激酶B[PKB(ser437)]蛋白相对表达量. 结果 与对照组相比,CTRP3干预组(10、50、250 ng/ml)葡萄糖消耗量分别增加了22.1％、42.9％及76.6％(P均＜0.01),PI3K蛋白相对表达量分别增加了62.5％、100.0％及137.5％(P均＜0.01),PKB(ser437)蛋白相对表达量分别增加了46.4％、160.7％及192.9％(P均＜0.01);与CTRP3(250 ng/ml)干预组相比,CTRP3 (250 ng/ml) +Wortmannin干预组葡萄糖消耗量下降53.2％ (P＜0.01),PI3K及PKB(ser437)蛋白相对表达量分别下降了43.4％及56.1％(P均＜0.01). 结论 脂肪因子CTRP3可能通过改善胰岛素信号转导增加IR的3T3-L1脂肪细胞IS.     

尾加压素Ⅱ促进大鼠心肌胶原蛋白表达及乳鼠心肌成纤维细胞的增殖

目的探讨尾加压素Ⅱ(UⅡ)对大鼠心肌纤维化的影响。方法腹主动脉缩窄术建立慢性压力超负荷大鼠心力衰竭模型,大鼠分为假手术组、造模4、8和12周组。利用Western blot分析心肌组织中UⅡ、G蛋白偶联受体(GPR14)、胶原Ⅰ(col-Ⅰ)、Ⅲ(col-Ⅲ)及蛋白激酶A(PKA)的表达。体外培养乳鼠成纤维细胞,分为对照组、UⅡ处理组、UⅡ+KT5720处理组及UII+SB-611812组。镜下观察及CKK-8法检测细胞增殖。结果模型组大鼠心肌组织中UⅡ、GPR14、col-Ⅰ、col-Ⅲ蛋白及PKA的表达显著增加,且呈时间依赖性。UⅡ促进乳鼠成纤维细胞(CFs)的增殖(P0.05),而KT5720、SB-611812可抑制UⅡ对乳鼠成纤维细胞的促增殖作用。结论 UⅡ及其受体系统促进大鼠心肌纤维化的发生发展。     

Tumor necrosis factor receptor- associated factor 6 (TRAF6) regulation of development,function, and homeostasis of the immune system

Tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6) is an adapter protein that mediates a wide array of protein–protein interactions via its TRAF domain and a RING finger domain that possesses non-conventional E3 ubiquitin ligase activity. First identified nearly two decades ago as a mediator of interleukin-1 receptor (IL-1R)-mediated activation of NFκB, TRAF6 has since been identified as an actor downstream of multiple receptor families with immunoregulatory functions, including members of the TNFR superfamily, the Toll-like receptor (TLR) family, tumor growth factor-β receptors (TGFβR), and T-cell receptor (TCR). In addition to NFκB, TRAF6 may also direct activation of mitogen-activated protein kinase (MAPK), phosphoinositide 3-kinase (PI3K), and interferon regulatory factor pathways. In the context of the immune system, TRAF6-mediated signals have proven critical for the development, homeostasis, and/or activation of B cells, T cells, and myeloid cells, including macrophages, dendritic cells, and osteoclasts, as well as for organogenesis of thymic and secondary lymphoid tissues. In multiple cellular contexts, TRAF6 function is essential not only for proper activation of the immune system but also for maintaining immune tolerance, and more recent work has begun to identify mechanisms of contextual specificity for TRAF6, involving both regulatory protein interactions, and messenger RNA regulation by microRNAs.     

Recruitment of activating NK‐cell receptors 2B4 and NKG2D to membrane microdomains in mammalian cells is dependent on their transmembrane regions

Membrane microdomains play an important role in the regulation of natural killer (NK) cell activities. These cholesterol‐rich membrane domains are enriched at the activating immunological synapse and several activating NK‐cell receptors are known to localize to membrane microdomains upon receptor engagement. In contrast, inhibitory receptors do not localize in these specialized membrane domains. In addition, the functional competence of educated NK cells correlates with a confinement of activating receptors in membrane microdomains. However, the molecular basis for this confinement is unknown. Here, we investigate the structural requirements for the recruitment of the human‐activating NK‐cell receptors NKG2D and 2B4 to detergent‐resistant membrane fractions in the murine BA/F3 cell line and in the human NK‐cell line NKL. This stimulation‐dependent recruitment occurred independently of the intracellular domains of the receptors. However, either interfering with the association between NKG2D and DAP10, or mutating the transmembrane region of 2B4 impacted the recruitment of the receptors to detergent‐resistant membrane fractions and modulated the function of 2B4 in NK cells. Our data suggest a potential interaction between the transmembrane region of NK‐cell receptors and membrane lipids as a molecular mechanism involved in determining the membrane confinement of activating NK‐cell receptors.     

Surmounting limited gene delivery into primary immune cell populations: Efficient cell type‐specific adenoviral transduction by CAR

Ectopic gene expression studies in primary immune cells have been notoriously difficult to perform due to the limitations in conventional transfection and viral transduction methods. Although replication‐defective adenoviruses provide an attractive alternative for gene delivery, their use has been hampered by the limited susceptibility of murine leukocytes to adenoviral infection, due to insufficient expression of the human coxsackie/adenovirus receptor (CAR). In this issue of the European Journal of Immunology, Heger et al. [Eur. J. Immunol. 2015. 45: 1614–1620] report the generation of transgenic mice that enable conditional Cre/loxP‐mediated expression of human CAR. The authors demonstrate that this R26/CAG‐CAR?1^StopF mouse strain facilitates the faithful monitoring of Cre activity in situ as well as the specific and efficient adenoviral transduction of primary immune cell populations in vitro. Further tweaking of the system towards more efficient gene transfer in vivo remains a future challenge.     

Evaluation of cardiac signals using discrete wavelet transform with MATLAB graphical user interface

Aim

To process the electrocardiogram (ECG) signals using MATLAB-based graphical user interface (GUI) and to classify the signals based on heart rate.

Method

The subject condition was identified using R-peak detection based on discrete wavelet transform followed by a Bayes classifier that classifies the ECG signals. The GUI was designed to display the ECG signal plot.

Results

Obtained from MIT database 18 patients had normal heart rate and 9 patients had abnormal heart rate; 14.81% of the patients suffered from tachycardia and 18.52% of the patients have bradycardia.

Conclusion

The proposed GUI display was found useful to analyze the digitized ECG signal by a non-technical user and may help in diagnostics. Further improvement can be done by employing field programmable gate array for the real time processing of cardiac signals.