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     

异质水分环境下野牛草相连分株间光合同化物的生理整合及其调控

异质环境下,克隆植物通过生理整合机制使资源在分株间实现共享,提高了其对异质性环境的适应能力,具有重要的生态进化意义,研究生理整合机制及其调控机理可为进一步发掘克隆植物应用潜力提供理论依据。以野牛草3个相连分株为材料,对其中一个分株用30%聚乙二醇6000(PEG-6000)模拟水分胁迫,通过Hoagland营养液培养试验,研究了异质水分环境下光合同化物在野牛草相连分株间的生理整合及分株叶片与根系内源激素ABA与IAA含量的变化规律。结果表明,14C-光合同化物在克隆片断内存在双向运输,但以向顶运输为主,异质水分环境下,受胁迫分株光合同化物的输出率明显降低,而与其相邻分株合成的光合同化物向受胁迫分株方向运输率明显增加;异质水分环境下,各分株ABA含量均明显增加,但以受胁迫的分株叶片及根系ABA的含量增加幅度最大,各分株IAA含量较对照均显著下降(P0.05),且以受胁迫分株IAA含量下降幅度最大;各分株叶片与根系ABA/IAA均显著提高(P0.05),相邻分株ABA/IAA增加幅度低于受胁迫分株。异质水分环境影响野牛草克隆分株间光合同化物的生理整合,且ABA与IAA在分株间光合同化物运输与分配过程中具有重要的调节作用。     

植物光信号途径重要新调控因子TZP的研究进展

TZP(TANDEM ZINC-FINGER/PLUS3)是近年来鉴定到的一个光信号转导途径新组分,在光介导的植物生长发育过程中发挥重要调控作用。TZP不仅负调控蓝光信号途径,参与光敏色素B(phyB)介导的开花调控过程,还参与调控phyA在体内的蛋白质磷酸化。对TZP生化活性和作用机制的深入研究,不仅有助于进一步完善光信号调控网络,也可为设计和培育具有耐密理想株型及高光效作物新品种提供理论依据。该文系统总结了TZP在植物光信号途径中发挥的重要调控作用,并提出未来TZP功能研究的重要问题。     

Caveolin-1 identified as a key mediator of acute lung injury using bioinformatics and functional research

Acute lung injury (ALI) is a potentially life-threatening, devastating disease with an extremely high rate of mortality. The underlying mechanism of ALI is currently unclear. In this study, we aimed to confirm the hub genes associated with ALI and explore their functions and molecular mechanisms using bioinformatics methods. Five microarray datasets available in GEO were used to perform Robust Rank Aggregation (RRA) to identify differentially expressed genes (DEGs) and the key genes were identified via the protein-protein interaction (PPI) network. Lipopolysaccharide intraperitoneal injection was administered to establish an ALI model. Overall, 40 robust DEGs, which are mainly involved in the inflammatory response, protein catabolic process, and NF-κB signaling pathway were identified. Among these DEGs, we identified two genes associated with ALI, of which the CAV-1/NF-κB axis was significantly upregulated in ALI, and was identified as one of the most effective targets for ALI prevention. Subsequently, the expression of CAV-1 was knocked down using AAV-shCAV-1 or CAV-1-siRNA to study its effect on the pathogenesis of ALI in vivo and in vitro. The results of this study indicated that CAV-1/NF-κB axis levels were elevated in vivo and in vitro, accompanied by an increase in lung inflammation and autophagy. The knockdown of CAV-1 may improve ALI. Mechanistically, inflammation was reduced mainly by decreasing the expression levels of CD3 and F4/80, and activating autophagy by inhibiting AKT/mTOR and promoting the AMPK signaling pathway. Taken together, this study provides crucial evidence that CAV-1 knockdown inhibits the occurrence of ALI, suggesting that the CAV-1/NF-κB axis may be a promising therapeutic target for ALI treatment.Subject terms: Cell signalling, Respiratory tract diseases     

Development and Validation of a DNA Methylation-related Classifier of Circulating Tumour Cells to Predict Prognosis and to provide a therapeutic strategy in Lung Adenocarcinoma

Background: A significant factor influencing the prognosis of lung adenocarcinoma (LUAD) is tumor metastasis. Studies have shown that abnormal DNA methylation in circulating tumor cells (CTCs) is associated with tumour metastasis. Based on the genes expressed in CTCs that play an important role in DNA methylation, we hope to build a risk model to predict prognosis and provide a therapeutic strategy in LUAD.Methods: The CTC sequencing data for LUAD were obtained from {"type":"entrez-geo","attrs":{"text":"GSE74639","term_id":"74639"}}GSE74639, which contains 10 CTC samples and 6 primary tumour samples. To carefully assess the clinical value, functional status, involvement of the tumor microenvironment (TME) based on the risk model, and genetic variants based on based on data from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO), a reliable risk model was successfully built.Results: Three differentially methylated genes (DMGs) of CTCs for LUAD, including mitochondrial ribosomal protein L51 (MRPL51), STE20-like kinase (SLK), and protein regulator of cytokinesis 1(PRC1), were effectively used to construct a risk model. Both the training and validation cohorts'' stability and accuracy of the risk model were evaluated. Each patient in the TCGA-LUAD cohort received a risk score, and based on the median score, they were divided into high- and low-risk groups. The tumors in the high-risk group in this study were classified as "cold" and immunosuppressed, which may be linked to a poor prognosis. The tumors in the low-risk group, however, were deemed "hot" and had immune hyperfunction linked to a positive prognosis. Additionally, patients in the low-risk group showed greater sensitivity to immunotherapy than those in the high-risk group.Conclusions: Based on DMGs of CTCs from LUAD, we successfully developed a predictive risk model and discovered differences in biological function, TME, genetic variation, and clinical outcomes between those at high and low risk group.     

Age‐related memory vulnerability to interfering stimuli is caused by gradual loss of MAPK‐dependent protection in Drosophila

Age‐related memory impairment (AMI) is a common phenomenon across species. Vulnerability to interfering stimuli has been proposed to be an important cause of AMI. However, the molecular mechanisms underlying this vulnerability‐related AMI remain unknown. Here we show that learning‐activated MAPK signals are gradually lost with age, leading to vulnerability‐related AMI in Drosophila. Young flies (2‐ or 3‐day‐old) exhibited a significant increase in phosphorylated MAPK levels within 15 min after learning, whereas aged flies (25‐day‐old) did not. Compared to 3‐day‐old flies, significant 1 h memory impairments were observed in 15‐, 20‐, and 30‐day‐old flies, but not in 10‐day‐old flies. However, with post‐learning interfering stimuli such as cooling or electric stimuli, 10‐day‐old flies had worse memory performance at 1 h than 3‐day‐old flies, showing a premature AMI phenomenon. Increasing learning‐activated MAPK signals through acute transgene expression in mushroom body (MB) neurons restored physiological trace of 1 h memory in a pair of MB output neurons in aged flies. Decreasing such signals in young flies mimicked the impairment of 1 h memory trace in aged flies. Restoring learning‐activated MAPK signals in MB neurons in aged flies significantly suppressed AMI even with interfering stimuli. Thus, our data suggest that age‐related loss of learning‐activated neuronal MAPK signals causes memory vulnerability to interfering stimuli, thereby leading to AMI.     

角毛壳菌几丁质酶基因chi58多点突变及在毕赤酵母中的高效表达

应用重叠延伸PCR技术(gene splicing by overlap extension PCR,gene SOEing),简称SOE-PCR对角毛壳菌(Chaetomium cupreum)的几丁质酶基因chi58进行多点突变.依据毕赤酵母密码子偏爱性,将毕赤酵母中编码Arg使用频率几乎为0的密码子CGC突变为使用频率高的AGA,构建了含有正确突变的酵母表达载体pPIC9K-chi58A,电转化毕赤酵母GS115,获得的重组酵母株在诱导120 h酶活力最高,平均可达101.71 U/mL±3.33 U/mL;其活力比未优化重组酵母株(31.83 U/mL±4.85 U/mL)提高了约3倍,且经10代传代培养后遗传稳定性良好.表达产物的SDS-PAGE分析表明,酶蛋白分子大小为58 kD.     

从宏基因组学切入探讨老年性阴道炎阴道微生态的微观整体性

老年性阴道炎是女性绝经后的常见病、多发病,西医认为该病的病因为绝经后或长期闭经后雌激素水平降低,阴道微生态失衡。宏基因组学是近年出现的菌群整体性检测方法,采用宏基因组学技术检测老年性阴道的微观整体状况,将为本病中医证型及疗效评定提供客观精确的量化标准。     

Determination of cefazedone in human plasma by high performance liquid chromatography–tandem mass spectrometry: Application to a pharmacokinetic study on Chinese volunteers

A rapid, sensitive and simple high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method was developed for determination of cefazedone in human plasma using metronidazole as internal standard (IS). The chromatographic separation was achieved on an Ultimate XB-CN column (2.1 mm × 150 mm, 5 μm) with an isocratic mobile phase of acetonitrile and 20 mM ammonium acetate in 0.1% formic acid in water (15:85, v/v). Detection was performed using electrospray ionization in positive ion multiple reaction-monitoring mode (SRM), monitoring the transitions m/z 548.2 → 344.1 for cefazedone and m/z 172.2 → 128.1 for IS. Calibration curves were linear over a wide range of 0.20–401.12 μg/mL for cefazedone in plasma. The lower limit of quantification (LLOQ) was 0.20 μg/mL. The intra- and inter-day precisions were less than 7.2%. The average recovery of cefazedone was 90.8–91.0%. The validated method was successfully applied to the pharmacokinetic study of cefazedone in Chinese healthy volunteers following intravenous (IV) administration of 500, 1000 and 2000 mg cefazedone injection.