Dll3 is expressed in developing hair cells in the mammalian cochlea.

Notch mediates the process of lateral inhibition that controls the production of hair cells in the inner ear. Hair cells are known to express Notch ligands Dll1 and Jag2, which signal through Notch1 in adjacent supporting cells. However, recent genetic and pharmacological studies indicate that the level of Notch-mediated lateral inhibition is greater than can be accounted for by Dll1 and Jag2. Here, we report that another Notch ligand, Dll3, is expressed in developing hair cells, in a pattern that overlaps that of Dll1 and Jag2. We analyzed the cochleae of Dll3(pu) mutant mice, but did not detect any abnormalities. However, earlier studies have demonstrated that there is functional redundancy among Notch ligands in cochlear development and loss of one ligand can be at least partially compensated for by another. Thus Dll3 may play a role in lateral inhibition similar to that of Dll1 and Jag2.     

Notch1 expression on T cells is not required for CD4+ T helper differentiation

Notch1 proteins are involved in binary cell fate decisions. To determine the role of Notch1 in the differentiation of CD4(+) Th1 versus Th2 cells, we have compared T helper polarization in vitro in naive CD4(+) T cells isolated from mice in which the N1 gene is specifically inactivated in all mature T cells. Following activation, Notch1-deficient CD4(+) T cells transcribed and secreted IFN-gamma under Th1 conditions and IL-4 under Th2 conditions at levels similar to that of control CD4(+) T cells. These results show that Notch1 is dispensable for the development of Th1 and Th2 phenotypes in vitro. The requirement for Notch1 in Th1 differentiation in vivo was analyzed following inoculation of Leishmania major in mice with a T cell-specific inactivation of the Notch1 gene. Following infection, these mice controlled parasite growth at the site of infection and healed their lesions. The mice developed a protective Th1 immune response characterized by high levels of IFN-gamma mRNA and protein and low levels of IL-4 mRNA with no IL-4 protein in their lymph node cells. Taken together, these results indicate that Notch1 is not critically involved in CD4(+) T helper 1 differentiation and in resolution of lesions following infection with L. major.     

川芎赤芍对脑缺血再灌注大鼠模型GFAP、VEGF及Notch1表达的影响

目的：本研究主要观察川芎赤芍对大鼠脑梗死再灌注后外周血胶质纤维酸性蛋白（GFAP）、血管内皮生长因子（VEGF）和脑内Notch1表达的影响。方法：采用线栓法制备大鼠脑缺血再灌注模型,将健康SD大鼠按随机数字表法随机分为空白组、模型组、川芎赤芍低剂量组、川芎赤芍高剂量组、银杏叶片组。采用ELISA法测定大鼠外周血GFAP、VEGF含量,采用real-time PCR法检测缺血脑组织Notch1 mRNA表达。结果：与模型组相比,川芎赤芍能够提高外周血GFAP、VEGF水平,上调脑组织Notch1 mRNA 的表达。结论：川芎赤芍可升高缺血再灌注大鼠外周血GFAP、VEGF的水平及缺血脑组织Notch1 mRNA的表达。     

Notch信号通路与肿瘤的发生及其靶向抗肿瘤疗法

综述Notch信号通路的组成、生理作用和转导途径,探讨Notch信号通路紊乱与肿瘤发生的关系及诱导肿瘤形成的机制,并概述Notch信号通路靶向肿瘤疗法的研究,包括对γ-分泌酶抑制剂、Notch受体拮抗剂和Notch-l小分子干扰RNA的研发。Notch信号通路在决定细胞命运中发挥着重要作用,它参与调控许多与肿瘤发生有关的细胞功能和微环境,包括细胞增殖、凋亡、黏附、上皮一间质转化以及血管发生等生物学过程,有望成为肿瘤治疗的新靶点。     

Notch信号通路相关基因与乳腺癌发生发展的研究新进展

Notch信号通路是一条进化上十分保守的信号转导途径,广泛存在于生物进化过程中,相邻细胞间通过Notch受体与配体的相互作用转导细胞信号,调节细胞的增殖、分化和凋亡,影响器官形成和形态的发生。近年大量研究表明Notch信号分子的异常表达在乳腺癌发生过程中起着重要的调控作用,但该基因表达异常的内在机制还不清楚,本文就Notch基因表达及其表达机制与乳腺癌的发生关系进行综述。     

Notch信号在白血病中的作用机制与靶向治疗

Notch信号在细胞增殖、分化、生存、凋亡、抗肿瘤血管生成和自我更新中起重要作用。许多肿瘤均与Notch信号异常有关,在不同的肿瘤、同一肿瘤的不同发展阶段,甚至同一肿瘤的不同细胞系中Notch途径的作用都是不同的。最近研究发现,Notch信号异常与白血病的发病、细胞周期阻滞和治疗预后有关。在Notch途径的相关靶点设计药物阻断或活化Notch信号进行白血病的治疗有更广阔的前景。现就Notch信号的组成、活化与Notch信号在白血病中的作用机制和靶向治疗进行综述。     

橙皮素对舌癌细胞的生长抑制作用及其机制

目的:检测橙皮素对舌癌细胞生长及Notch1活化的影响,探讨橙皮素抑癌作用机制。方法:将培养的Tca8113细胞分为DMSO对照组和25、50、75、100和125 μmol·L^-1橙皮素处理组。MTT法检测不同浓度橙皮素作用后Tca8113细胞增殖抑制率,流式细胞术检测各组细胞凋亡率和细胞周期分布,定量PCR和免疫印迹分别用于分析橙皮素作用前后Tca8113细胞中Notch1和Hes-1 mRNA及蛋白表达。结果:与DMSO对照组比较,125 μmol·L^-1橙皮素处理组24、48和72 h Tca8113细胞增殖抑制率明显升高(7.88%±1.90%、26.28%±2.2%和47.05%±1.90%)(P<0.05);在橙皮素处理72 h后,25、50、75、100 和125 μmol·L^-1橙皮素处理组细胞增殖抑制率分别为(6.14±1.20)%、(28.69±2.10)%、(28.33±2.60)%、(45.26±3.00)%和(47.05±1.90)%,橙皮素对Tca8113细胞的增殖抑制作用呈现时间剂量依赖性。流式细胞术,橙皮素作用72 h后, 0、50和100 μmol·L^-1橙皮素处理组细胞凋亡百分率从 2.9%±0.5%升高至23.4%±1.7%和 35.1%± 1.9%(P<0.05);G₀/G₁期细胞由(18.6±1.3)%升高至(33.4±1.5)%和(40.5±1.9)%(P<0.05), S期细胞百分率由(70.3±2.5)%下降至(56.8±2.0)%和(48.7±1.8)%(P<0.05)。定量PCR和免疫印迹分析,与DMSO对照组比较,橙皮素作用后Tca8113细胞中Notch1和Hes-1 mRNA及蛋白表达水平明显升高(P<0.05)。结论:橙皮素能够抑制Tca8113细胞增殖并诱导其发生细胞凋亡和细胞周期G₀/G₁期阻滞,其机制可能与活化Notch1有关联。