H5N6 A型流感病毒(influenza A virus, IAV)是严重危害公共卫生安全的新发人兽共患病病原,其复制和致病的科学问题需进一步深入研究.细丝蛋白A(filamin A, FLNA)是一种多功能的肌动蛋白结合蛋白,其可作为细胞信号转导中的支架蛋白,广泛...H5N6 A型流感病毒(influenza A virus, IAV)是严重危害公共卫生安全的新发人兽共患病病原,其复制和致病的科学问题需进一步深入研究.细丝蛋白A(filamin A, FLNA)是一种多功能的肌动蛋白结合蛋白,其可作为细胞信号转导中的支架蛋白,广泛参与细胞内的多种重要生物学过程,但其在流感病毒感染与免疫过程中的作用尚未见报道.前期深度测序分析发现H5N6流感病毒感染细胞后可显著下调FLNA的表达水平,而FLNA过表达能够显著抑制流感病毒在细胞中的复制,并且可以活化Ⅰ型干扰素信号通路.通过siRNA或抑制剂阻断Ⅰ型干扰素下游信号通路之后, FLNA对流感病毒复制的抑制作用消失.以上结果表明, FLNA可以通过活化Ⅰ型干扰素信号通路来抑制H5N6流感病毒在细胞中的复制.本文阐明了FLNA蛋白在流感病毒复制过程中的作用,发现了FLNA参与细胞天然免疫反应的新功能,同时为抗流感病毒药物研发提供了理论依据和研究思路.展开更多
On March 31, 2013, the National Health and Family Planning Commission announced that human infections with a previously undescribed influenza A (H7N9) virus had occurred in Shanghai and Anhui Province, China. To inves...On March 31, 2013, the National Health and Family Planning Commission announced that human infections with a previously undescribed influenza A (H7N9) virus had occurred in Shanghai and Anhui Province, China. To investigate the possible origins of the H7N9 viruses causing these human infections, we collected 970 samples, including drinking water, soil, and cloacal and tracheal swabs of poultry from live poultry markets and poultry farms in Shanghai and Anhui Province. Twenty samples were positive for the H7N9 influenza virus. Notably, all 20 viruses were isolated from samples collected from live poultry markets in Shanghai. Phylogenetic analyses showed that the six internal genes of these novel human H7N9 viruses were derived from avian H9N2 viruses, but the ancestor of their HA and NA genes is uncertain. When we examined the phylogenetic relationship between the H7N9 isolates from live poultry markets and the viruses that caused the human infections, we found that they shared high homology across all eight gene segments. We thus identified the direct avian origin of the H7N9 influenza viruses that caused the human infections. Importantly, we observed that the H7N9 viruses isolated from humans had acquired critical mutations that made them more "human-like". It is therefore imperative to take strong measures to control the spread of H7N9 viruses in birds and humans to prevent further threats to human health.展开更多
文摘【目的】流感病毒是一种人兽共患病原,常引起大流行,给人类健康造成巨大威胁,且流感病毒易发生变异,能不断逃逸宿主细胞的免疫反应,对现有抗流感药物产生耐药性,因此寻找抵抗流感的新方法迫在眉睫。研究通过探索NMRAL1(NmrA-like family domain-containing protein 1)对流感病毒复制的影响,并揭示其发挥作用的分子机制,为抗流感药物研发提供潜在靶点。【方法】采用siRNA干扰技术在A549细胞中下调表达NMRAL1,并通过Western Blot检测siRNA干扰后NMRAL1的表达水平;在下调表达NMRAL1的细胞中,分别感染A/Anhui/2/2005(AH05)(H5N1)和A/WSN/33(H1N1)两株不同亚型流感病毒,利用蚀斑试验检测感染病毒后24和48 h细胞上清中的病毒滴度。为确定NMRAL1影响流感病毒复制的具体阶段,在HEK293T细胞中瞬时转染NMRAL1-Myc-pCAGGS质粒过表达NMRAL1,通过双荧光素酶报告系统检测过表达NMRAL1对流感病毒聚合酶活性的影响;使用免疫荧光技术对流感病毒NP蛋白进行染色,通过激光共聚焦试验观察下调表达NMRAL1对感染病毒后3、4、5、6和8 h NP蛋白在被感染细胞中的定位情况的影响,判断下调表达NMRAL1是否影响流感病毒的入核和出核过程;利用Western Blot检测下调表达NMRAL1对流感病毒各病毒蛋白表达的影响和对流感病毒激活I型干扰素通路下游IFN刺激基因(ISGs)表达的影响,利用间接免疫荧光试验进一步研究NMRAL1对流感病毒复制的影响。【结果】Western Blot检测发现NMRAL1 siRNA能显著下调NMRAL1表达,在下调表达NMRAL1的A549细胞中分别感染H5N1和H1N1病毒,并通过蚀斑试验检测感染病毒后细胞上清中的病毒滴度,结果显示在下调表达NMRAL1的细胞中,感染流感病毒后24和48 h收取的细胞上清中病毒滴度显著下降,表明NMRAL1能促进不同亚型流感病毒的复制;为进一步探索NMRAL1调控流感病毒复制的具体机制,利用双荧光素酶报告系统检测流感病毒聚合酶活性,发现过表达NMRAL1对流感病毒聚合酶活性无明显影响;激光共聚焦试验结果显示下调NMRAL1表达不影响NP蛋白的入核和出核过程,同时Western Blot检测表明下调NMRAL1表达不影响各病毒蛋白的表达;但荧光定量PCR试验结果显示下调NMRAL1表达能够促进流感病毒感染诱导的IFN-βmRNA水平上升,且Western Blot检测发现下调表达NMRAL1促进I型干扰素通路下游的MxA和IFITM3抗病毒蛋白的表达,与此同时,间接免疫荧光试验结果显示下调NMRAL1表达可显著抑制流感病毒复制。【结论】在流感病毒感染过程中,NMRAL1不影响流感病毒的入侵以及转录翻译过程,而是通过抑制I型干扰素通路激活从而抑制MxA、IFITM3等抗病毒因子的表达,最终促进流感病毒复制。研究证实宿主因子NMRAL1正调控流感病毒的复制,丰富了参与流感病毒复制的宿主因子网络。
文摘H5N6 A型流感病毒(influenza A virus, IAV)是严重危害公共卫生安全的新发人兽共患病病原,其复制和致病的科学问题需进一步深入研究.细丝蛋白A(filamin A, FLNA)是一种多功能的肌动蛋白结合蛋白,其可作为细胞信号转导中的支架蛋白,广泛参与细胞内的多种重要生物学过程,但其在流感病毒感染与免疫过程中的作用尚未见报道.前期深度测序分析发现H5N6流感病毒感染细胞后可显著下调FLNA的表达水平,而FLNA过表达能够显著抑制流感病毒在细胞中的复制,并且可以活化Ⅰ型干扰素信号通路.通过siRNA或抑制剂阻断Ⅰ型干扰素下游信号通路之后, FLNA对流感病毒复制的抑制作用消失.以上结果表明, FLNA可以通过活化Ⅰ型干扰素信号通路来抑制H5N6流感病毒在细胞中的复制.本文阐明了FLNA蛋白在流感病毒复制过程中的作用,发现了FLNA参与细胞天然免疫反应的新功能,同时为抗流感病毒药物研发提供了理论依据和研究思路.
基金supported by the National Basic Research Program of China,the China Agricultural Research System (CARS-42-G08)the National Science and Technology Major Project (2012ZX10004214)
文摘On March 31, 2013, the National Health and Family Planning Commission announced that human infections with a previously undescribed influenza A (H7N9) virus had occurred in Shanghai and Anhui Province, China. To investigate the possible origins of the H7N9 viruses causing these human infections, we collected 970 samples, including drinking water, soil, and cloacal and tracheal swabs of poultry from live poultry markets and poultry farms in Shanghai and Anhui Province. Twenty samples were positive for the H7N9 influenza virus. Notably, all 20 viruses were isolated from samples collected from live poultry markets in Shanghai. Phylogenetic analyses showed that the six internal genes of these novel human H7N9 viruses were derived from avian H9N2 viruses, but the ancestor of their HA and NA genes is uncertain. When we examined the phylogenetic relationship between the H7N9 isolates from live poultry markets and the viruses that caused the human infections, we found that they shared high homology across all eight gene segments. We thus identified the direct avian origin of the H7N9 influenza viruses that caused the human infections. Importantly, we observed that the H7N9 viruses isolated from humans had acquired critical mutations that made them more "human-like". It is therefore imperative to take strong measures to control the spread of H7N9 viruses in birds and humans to prevent further threats to human health.
