对于包括铜绿假单胞菌在内的众多微生物而言,群体感应系统是细菌表达毒力因子的重要调节子.Las和Rhl是群体感应两个主要组成部分.Las和Rhl分别受自诱导剂N-3-氧化十二烷酰基-L-高丝氨酸内酯(3-oxo-C12-HSL)和N-丁酰-L-高丝氨酸内酯(C4-HSL)的影响.最近的研究进展显示群体感应分子尤其是3-oxo-C12-HSL具有调节宿主免疫系统的能力.本实验展示了3-oxo-C12-HSL可以诱导鼠源巨噬细胞(RAW264.7)的凋亡和吞噬作用.把合成的3-oxo-C12-HSL加入RAW264.7细胞培养基中,发现细胞生活力以一种依赖于3-oxo-C12-HSL的浓度(6.25 to 100μmol/L)和培养时间(2 to 24 h)的方式逐渐丢失.同样,我们观察到3-oxo-C12-HSL的细胞毒活性,用3-oxo-C12-HSL处理的细胞出现细胞形态上的改变,这一改变表明3-oxo-C12-HSL处理的细胞加速凋亡,这一点同时也被其他多个标准(caspases3、8和9,线粒体膜电位,磷脂酰丝氨酸的表达)所证实.中性红吞饮实验证明,3-oxo-C12-HSL会显著地减小RAW264.7细胞的吞噬能力(P<0.05).同时,高浓度的3-oxo-C12-HSL会降低RAW264.7细胞对铜绿假单胞菌的吞噬作用(P<0.001).这些数据表明3-oxo-C12-HSL能特异性地促进细胞凋亡的诱导和RAW264.7细胞吞噬能力的减小.这可能和3-oxo-C12-HSL诱导的细胞毒性有关.最终我们的实验数据证明,群体感应信号分子3-oxo-C12-HSL在铜绿假单胞菌感染的致病机理中扮演着重要的角色.
Objective To observe the activating effect of ciliary neurotrophic factor （CNTF） on astrocyte in vitro. Methods Astrocytes cultured purely from newborn rats. Cerebral cortex was raised in normal and serum deprivatio...
详细信息
Objective To observe the activating effect of ciliary neurotrophic factor （CNTF） on astrocyte in vitro. Methods Astrocytes cultured purely from newborn rats. Cerebral cortex was raised in normal and serum deprivation condition with different concentrations （in ng/ml： 0, 2, 20, or 200） of CNTF. After cultured for 24 h, the shape and the cell cycle of astrocytes were examined by immunocytochemistry and flow cytometer, respectively. Results The immunoactivity of glial fibrillary acidic protein （GFAP） and the nuclear size of astrocytes were increased when CNTF was applied, whether cells were cultured in medium with or without serum. CNTF promoted astrocytes to enter the cell cycle in medium with serum, but had no this effect in medium without serum. Conclusion In medium without serum, astrocytes could differentiate into activated state ceils with CNTF application, but could not proliferate; in medium with serum, astrocytes could proliferate with aid of CNTF.
目的探讨人卵巢癌顺铂耐药细胞株A2780/DDP、COC1/DDP中抗凋亡基因bcl-XL、细胞色素c的表达和半胱天冬氨酸蛋白酶-3 (caspase-3) 活性对人卵巢癌顺铂耐药的影响.方法采用逆转录聚合酶链反应(RT-PCR)和Western blot 检测人卵巢癌顺铂敏...
详细信息
目的探讨人卵巢癌顺铂耐药细胞株A2780/DDP、COC1/DDP中抗凋亡基因bcl-XL、细胞色素c的表达和半胱天冬氨酸蛋白酶-3 (caspase-3) 活性对人卵巢癌顺铂耐药的影响.方法采用逆转录聚合酶链反应(RT-PCR)和Western blot 检测人卵巢癌顺铂敏感细胞株A2780、COC1和顺铂耐药株A2780/DDP、COC1/DDP中bcl-XL的表达,以及顺铂作用后细胞色素c的含量和caspase-3活性的变化,并应用流式细胞仪测定顺铂作用后A2780、COC1、A2780/DDP、COC1/DDP细胞的凋亡率.结果bcl-XL在A2780/DDP、COC1/DDP细胞中的表达明显高于A2780、COC1细胞;顺铂作用后,细胞色素c在A2780/DDP、COC1/DDP细胞中的表达明显减少,caspase-3活性和凋亡率也较A2780和COC1细胞明显降低(P<0.05).结论人卵巢癌细胞对顺铂产生耐药可能与细胞内bcl-XL过度表达、细胞色素c释放受抑制和caspase-3活性下降有关.
暂无评论