SARS-CoV-2 envelope protein causes acute respiratory distress syndrome (ARDS)-like pathological damages and constitutes an antiviral target

Cytokine storm and multi-organ failure are the main causes of SARS-CoV-2-related death. However, the origin of excessive damages caused by SARS-CoV-2 remains largely unknown. Here we show that the SARS-CoV-2 envelope (2-E) protein alone is able to cause acute respiratory distress syndrome (ARDS)-like damages in vitro and in vivo. 2-E proteins were found to form a type of pH-sensitive cation channels in bilayer lipid membranes. As observed in SARS-CoV-2-infected cells, heterologous expression of 2-E channels induced rapid cell death in various susceptible cell types and robust secretion of cytokines and chemokines in macrophages. Intravenous administration of purified 2-E protein into mice caused ARDS-like pathological damages in lung and spleen. A dominant negative mutation lowering 2-E channel activity attenuated cell death and SARS-CoV-2 production. Newly identified channel inhibitors exhibited potent anti-SARS-CoV-2 activity and excellent cell protective activity in vitro and these activities were positively correlated with inhibition of 2-E channel. Importantly, prophylactic and therapeutic administration of the channel inhibitor effectively reduced both the viral load and secretion of inflammation cytokines in lungs of SARS-CoV-2-infected transgenic mice expressing human angiotensin-converting enzyme 2 (hACE-2). Our study supports that 2-E is a promising drug target against SARS-CoV-2.Subject terms: Cell death, Molecular biology     

水稻对褐飞虱抗性相关蛋白的双向电泳分析

以药用野生稻 (Oryzaofficinalis)的转育后代B5 (高抗褐飞虱 (NilaparvatalugensSt l) )与感虫品种明恢 6 3(OryzasativaL .)为亲本 ,构建了一个重组自交系群体。通过抗褐飞虱鉴定 ,筛选出极端抗虫株系和极端感虫株系 ,运用分群分析法 (bulkedsegregantanalysis ,BSA)分别建成了极端抗虫集团 (resistantbulk)和极端感虫集团 (susceptiblebulk)的蛋白质池。利用双向电泳技术 ,分别分析了极端抗虫集团和极端感虫集团受虫害与未受虫害的秧苗蛋白质的变化。结果发现 ,虫害 48h后 ,感虫集团的一个分子量为 40kD的蛋白质P40 (pI=6 .3)的表达明显减弱甚至消失 ,而在抗虫集团中 ,P40的表达未受影响。与褐飞虱为害后抗虫株系和感虫株系不同的生理反应相联系 ,推测P40与水稻受褐飞虱虫害后引起的应答反应相关     

Inhibition of Filamin-A Reduces Cancer Metastatic Potential

Filamin-A cross-links actin filaments into dynamic orthogonal networks, and interacts with an array of proteins of diverse cellular functions. Because several filamin-A interaction partners are implicated in signaling of cell mobility regulation, we tested the hypothesis that filamin-A plays a role in cancer metastasis. Using four pairs of filamin-A proficient and deficient isogenic cell lines, we found that filamin-A deficiency in cancer cells significantly reduces their migration and invasion. Using a xenograft tumor model with subcutaneous and intracardiac injections of tumor cells, we found that the filamin-A deficiency causes significant reduction of lung, splenic and systemic metastasis in nude mice. We evaluated the expression of filamin-A in breast cancer tissues by immunohistochemical staining, and found that low levels of filamin-A expression in cancer cells of the tumor tissues are associated with a better distant metastasis-free survival than those with normal levels of filamin-A. These data not only validate filamin-A as a prognostic marker for cancer metastasis, but also suggest that inhibition of filamin-A in cancer cells may reduce metastasis and that filamin-A can be used as a therapeutic target for filamin-A positive cancer.     

草甘膦对空心莲子草叶甲Agasicles hygrophila成虫3种代谢酶活性的影响

采用不同浓度的草甘膦0.41 g/L、0.82 g/L、1.23 g/L、1.64g/L、2.05 g/L分别以胃毒和触杀法处理空心莲子草叶甲Agasicles hygrophila成虫,测定其乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)和谷胱甘肽S-转移酶(GSTs)比活力.试验结果表明:两种处理,草甘膦对AChE活力均有不同程度的抑制作用;对CarE活力影响较为显著,在2.05 g/L浓度下,胃毒处理CarE对α-乙酸萘酯(α-NA)和β-乙酸萘酯(β-NA)水解能力分别是对照组的50%和57%,触杀处理CarE对α-乙酸萘酯(α-NA)和β-乙酸荼酯(β-NA)水解能力分别是对照组的53%和59%;胃毒处理埘酶活力影响大于触杀处理,草甘膦对GSTs的活力影响不明显.     

MicroRNA-30a sensitizes tumor cells to cis-platinum via suppressing beclin 1-mediated autophagy

Autophagy is activated in cancer cells during chemotherapy and often contributes to tumor chemotherapy resistance. In this study, we characterized the role of microRNA-30a (miR-30a) in the coordination of cancer cell apoptosis and autophagy, which determines the sensitivity of cancer cells to chemotherapy. First, the autophagy activity in cancer cells increased after cis-dichloro-diamine platinum (cis-DDP) or Taxol treatment, as indicated by the enhanced expression of beclin 1, a key regulator of autophagy, and increased number of LC3-positive autophagosomes. Second, miRNA screening using a TaqMan probe-based quantitative RT-PCR assay identified that miR-30a, a miRNA that targets beclin 1, was significantly reduced in tumor cells by cis-DDP treatment. Forced expression of miR-30a significantly reduced beclin 1 and the autophagy activity of tumor cells induced by cis-DDP. Third, the blockade of tumor cell autophagy activity by miR-30a expression or 3-methyladenine significantly increased tumor cell apoptosis induced by cis-DDP treatment. Finally, an in vivo tumor implantation mouse model clearly showed that elevation of miR-30a in implanted tumor cells by administration of the recombinant lentivirus expressing miR-30a strongly enhanced cis-DDP-induced apoptosis of tumor cells. In conclusion, our results demonstrate for the first time that miR-30a can sensitize tumor cells to cis-DDP via reducing beclin 1-mediated autophagy and that increasing miR-30a level in tumor cells represents a novel approach to enhance the efficacy of chemotherapy during cancer treatment.