Alpha-synuclein dynamics bridge Type-I Interferon response and SARS-CoV-2 replication in peripheral cells

BACKGROUND: Increasing evidence suggests a double-faceted role of alpha-synuclein (α-syn) following infection by a variety of viruses, including SARS-CoV-2. Although α-syn accumulation is known to contribute to cell toxicity and the development and/or exacerbation of neuropathological manifestations, it is also a key to sustaining anti-viral innate immunity. Consistently with α-syn aggregation as a hallmark of Parkinson's disease, most studies investigating the biological function of α-syn focused on neural cells, while reports on the role of α-syn in periphery are limited, especially in SARS-CoV-2 infection. RESULTS: Results herein obtained by real time qPCR, immunofluorescence and western blot indicate that α-syn upregulation in peripheral cells occurs as a Type-I Interferon (IFN)-related response against SARS-CoV-2 infection. Noteworthy, this effect mostly involves α-syn multimers, and the dynamic α-syn multimer:monomer ratio. Administration of excess α-syn monomers promoted SARS-CoV-2 replication along with downregulation of IFN-Stimulated Genes (ISGs) in epithelial lung cells, which was associated with reduced α-syn multimers and α-syn multimer:monomer ratio. These effects were prevented by combined administration of IFN-ß, which hindered virus replication and upregulated ISGs, meanwhile increasing both α-syn multimers and α-syn multimer:monomer ratio in the absence of cell toxicity. Finally, in endothelial cells displaying abortive SARS-CoV-2 replication, α-syn multimers, and multimer:monomer ratio were not reduced following exposure to the virus and exogenous α-syn, suggesting that only productive viral infection impairs α-syn multimerization and multimer:monomer equilibrium. CONCLUSIONS: Our study provides novel insights into the biology of α-syn, showing that its dynamic conformations are implicated in the innate immune response against SARS-CoV-2 infection in peripheral cells. In particular, our results suggest that promotion of non-toxic α-syn multimers likely occurs as a Type-I IFN-related biological response which partakes in the suppression of viral replication. Further studies are needed to replicate our findings in neuronal cells as well as animal models, and to ascertain the nature of such α-syn conformations.

Análisis de 23 pacientes con infección por VIH y Covid-19. Estudio descriptivo / Analysis of 23 patients with HIV infection and Covid-19. Descriptive study

Las características clínicas, el diagnóstico, el pronóstico, el tratamiento y la profilaxis de la infección por el coronavirus SARS-CoV-2 en los pacientes infectados por el VIH, son muy similares a los de la población general cuando estos se encuentran con supresión de la replicación viral con el tratamiento antirretroviral y tienen una cifra de linfocitos T CD4 + > de 200 células/uL. El tiempo medio de incubación es de 5 días (entre 2 y 14 días). En sujetos VIH positivos, cuánto mayor es la carga viral plasmática para VIH y el recuento de CD4 + es < 200 cél/uL, el tiempo que transcurre entre la infección por el coronavirus y la aparición de las manifestaciones clínicas es menor. En la población general, el 70-80% de individuos tienen una infección por SARS-CoV-2 leve/moderada, un 20-25% grave y un 5% muy grave que requiere internación en UTI. En los pacientes infectados por el VIH se desconoce esta proporción, aunque estudios preliminares consideran que las proporciones serían del 66%, 22% y 12%, respectivamente25. Se presenta una serie de 23 pacientes con coinfección SARS-CoV-2/VIH y se analizan las características epidemiológicas, clínicas y la evolución en relación con ambas infecciones

The clinical characteristics, diagnosis methods, medical prognosis, treatment alternatives and prophylaxis of coronavirus SARS-CoV-2 infection in HIV infected individuals are very similar in patients under HAART with undetectable viral load and CD4+ > than 200 cell/uL. The mean incubation time is of 5 days (range 2 to 14 days). In HIV-seropositive patients, with high viral load and CD4 < 200 cell/ uL, the time between infection for coronavirus and the onset of symptoms is minor. In the general population, 70% to 80% of individuals infected by SARS-CoV-2 develops a mild to moderate disease; 20% to 25% severe forms and 5% develops very severe clinical compromise that requieres intensive therapy unit income. In HIV-positive patients these percentages would be 66%, 22% y 12%, respectively25. Here we present a series of 23 HIV-seropositive patients coinfected by coronavirus SARS-CoV-2; we analyzed the epidemiology, clinical manifestations and the evolution related with both infections

Effects of host proteins interacting with non-structural protein nsp9 of porcine epidemic diarrhea virus on viral replication / 生物工程学报

Porcine epidemic diarrhea virus (PEDV) is a highly pathogenic virus that can cause acute intestinal infectious diseases in both piglets and fattening pigs. The virus encodes at least 16 non-structural proteins, including nsp9, which has been shown to bind to single-stranded RNA. However, its function and mechanism remain unclear. In this study, we aimed to identify potential host proteins that interact with PEDV nsp9 using immunoprecipitation combined with mass spectrometry. The interactions were then confirmed by co-immunoprecipitation (Co-IP) and confocal laser scanning fluorescence techniques. The results showed that nsp9 interacts with HSPA8, Tollip, HSPA9 and TOMM70. Among them, overexpression of HSPA8 resulted in caused first upregulated and then down-regulated expression of nsp9, and promoted the proliferation of PEDV. Overexpression of Tollip significantly upregulated the expression of nsp9 and inhibited the proliferation of PEDV. Overexpression of TOMM70 significantly reduced the expression of nsp9, but did not show significant effect on the proliferation of PEDV. Overexpression of HSPA9 did not show significant effect on the expression of nsp9 and the proliferation of PEDV. These findings may facilitate further investigating the role of nsp9-interacting proteins in PEDV infection.

Virus hijacking ESCRT system to promote self-replication: a review / 生物工程学报

Endosomal sorting complex required for transport (ESCRT) system drives various cellular processes, including endosome sorting, organelle biogenesis, vesicle transport, maintenance of plasma membrane integrity, membrane fission during cytokinesis, nuclear membrane reformation after mitosis, closure of autophagic vacuoles, and enveloped virus budding. Increasing evidence suggests that the ESCRT system can be hijacked by different family viruses for their proliferation. At different stages of the virus life cycle, viruses can interfere with or exploit ESCRT-mediated physiological processes in various ways to maximize their chance of infecting the host. In addition, many retroviral and RNA viral proteins possess "late domain" motifs, which can recruit host ESCRT subunit proteins to assist in virus endocytosis, transport, replicate, budding and efflux. Therefore, the "late domain" motifs of viruses and ESCRT subunit proteins could serve as promising drug targets in antiviral therapy. This review focuses on the composition and functions of the ESCRT system, the effects of ESCRT subunits and virus "late domain" motifs on viral replication, and the antiviral effects mediated by the ESCRT system, aiming to provide a reference for the development and utilization of antiviral drugs.

An atlas of immune cell transcriptomes in human immunodeficiency virus-infected immunological non-responders identified marker genes that control viral replication / 中华医学杂志(英文版)

BACKGROUND@#Previous studies have examined the bulk transcriptome of peripheral blood immune cells in acquired immunodeficiency syndrome patients experiencing immunological non-responsiveness. This study aimed to investigate the characteristics of specific immune cell subtypes in acquired immunodeficiency syndrome patients who exhibit immunological non-responsiveness.@*METHODS@#A single-cell transcriptome sequencing of peripheral blood mononuclear cells obtained from both immunological responders (IRs) (CD4 + T-cell count >500) and immunological non-responders (INRs) (CD4 + T-cell count <300) was conducted. The transcriptomic profiles were used to identify distinct cell subpopulations, marker genes, and differentially expressed genes aiming to uncover potential genetic factors associated with immunological non-responsiveness.@*RESULTS@#Among the cellular subpopulations analyzed, the ratios of monocytes, CD16 + monocytes, and exhausted B cells demonstrated the most substantial differences between INRs and IRs, with fold changes of 39.79, 11.08, and 2.71, respectively. In contrast, the CD4 + T cell ratio was significantly decreased (0.39-fold change) in INRs compared with that in IRs. Similarly, the ratios of natural killer cells and terminal effector CD8 + T cells were also lower (0.37-fold and 0.27-fold, respectively) in the INRs group. In addition to several well-characterized immune cell-specific markers, we identified a set of 181 marker genes that were enriched in biological pathways associated with human immunodeficiency virus (HIV) replication. Notably, ISG15 , IFITM3 , PLSCR1 , HLA-DQB1 , CCL3L1 , and DDX5 , which have been demonstrated to influence HIV replication through their interaction with viral proteins, emerged as significant monocyte marker genes. Furthermore, the differentially expressed genes in natural killer cells were also enriched in biological pathways associated with HIV replication.@*CONCLUSIONS@#We generated an atlas of immune cell transcriptomes in HIV-infected IRs and INRs. Host genes associated with HIV replication were identified as markers of, and were found to be differentially expressed in, different types of immune cells.

TRIM25 inhibits HBV replication by promoting HBx degradation and the RIG-I-mediated pgRNA recognition / 中华医学杂志(英文版)

BACKGROUND@#The hepatitis B virus (HBV) vaccine has been efficiently used for decades. However, hepatocellular carcinoma caused by HBV is still prevalent globally. We previously reported that interferon (IFN)-induced tripartite motif-containing 25 (TRIM25) inhibited HBV replication by increasing the IFN expression, and this study aimed to further clarify the anti-HBV mechanism of TRIM25.@*METHODS@#The TRIM25-mediated degradation of hepatitis B virus X (HBx) protein was determined by detecting the expression of HBx in TRIM25-overexpressed or knocked-out HepG2 or HepG2-NTCP cells via Western blotting. Co-immunoprecipitation was performed to confirm the interaction between TRIM25 and HBx, and colocalization of TRIM25 and HBx was identified via immunofluorescence; HBV e-antigen and HBV surface antigen were qualified by using an enzyme-linked immunosorbent assay (ELISA) kit from Kehua Biotech. TRIM25 mRNA, pregenomic RNA (pgRNA), and HBV DNA were detected by quantitative real-time polymerase chain reaction. The retinoic acid-inducible gene I (RIG-I) and pgRNA interaction was verified by RNA-binding protein immunoprecipitation assay.@*RESULTS@#We found that TRIM25 promoted HBx degradation, and confirmed that TRIM25 could enhance the K90-site ubiquitination of HBx as well as promote HBx degradation by the proteasome pathway. Interestingly, apart from the Really Interesting New Gene (RING) domain, the SPRY domain of TRIM25 was also indispensable for HBx degradation. In addition, we found that the expression of TRIM25 increased the recognition of HBV pgRNA by interacting with RIG-I, which further increased the IFN production, and SPRY, but not the RING domain is critical in this process.@*CONCLUSIONS@#The study found that TRIM25 interacted with HBx and promoted HBx-K90-site ubiquitination, which led to HBx degradation. On the other hand, TRIM25 may function as an adaptor, which enhanced the recognition of pgRNA by RIG-I, thereby further promoting IFN production. Our study can contribute to a better understanding of host-virus interaction.

A conceptual framework for dynamics of cccDNA in hepatitis B virus / 中华肝脏病杂志

The resolution of the hepatitis C issue has raised expectations for a chronic hepatitis B cure, driving the industry to expand investment in research and development efforts to strengthen functional cure strategies. These strategies have a wide variety of types, and the published research findings are heterogeneous. The theoretical analysis of these strategies is of great significance for determining prioritized research orientations as well as sensibly allocating research and development resources. However, due to a paucity of necessary conceptual models, current theoretical analysis has not been able to unify various therapeutic strategies into a proper theoretical framework. In view of the fact that the decrease in the quantity of cccDNA is an inevitable core event accompanied by the process of functional cure, this paper intends to analyze several chronic hepatitis B cure strategies using cccDNA dynamics as a framework. Furthermore, there are currently few studies on the dynamics of the cccDNA field, hoping that this article can promote recognition and research in this field.

Study of the interactions of di- and tri-terpenes from Stillingia loranthacea with the enzyme NSP16-NSP10 of SARS-CoV-2 / Estudo das interações de di- e tri-terpenos de Stillingia loranthacea com a enzima NSP16-NSP10 de SARS-CoV-2

Objective: This study aimed to evaluate the interactions of di- and tri-terpenes from Stillingia loranthacea with the enzyme NSP16-NSP10 of SARS-CoV-2, important for viral replication. Methods: The molecular docking technique was used to evaluate this interaction. Results: The analysis showed that the evaluated compounds obtained RMSD values of 0.888 to 1.944 Å and free energy of -6.1 to -9.4 kcal/mol, with the observation of hydrogen bonds, salt bridges, and pi-sulfur, pi-alkyl, and hydrophobic interactions. Conclusion: Thus, the results obtained show the potential of the compounds analyzed against the selected target. Since computer simulations are only an initial step in projects for the development of antiviral drugs, this study provides important data for future research.

Objetivo: avaliar as interações de di- e tri-terpenos de Stillingia loranthacea com a enzima NSP16-NSP10 de SARS-CoV-2, importante para a replicação viral. Métodos: A técnica de docking molecular foi utilizada para avaliar essa interação. Resultados: A análise mostrou que os compostos avaliados obtiveram valores de RMSD de 0,888 a 1,944 Å e energia livre de -6,1 a -9,4 kcal/mol, observando-se ligações de hidrogênio, pontes salinas e pi-enxofre, pi-alquil, e interações hidrofóbicas. Conclusão: Assim, os resultados obtidos mostram o potencial dos compostos analisados frente ao alvo selecionado. Como as simulações computacionais são apenas um passo inicial nos projetos de desenvolvimento de medicamentos antivirais, este estudo fornece dados importantes para pesquisas futuras.

Expresión de los componentes del inflamasoma y su relación con los marcadores de riesgo cardiovascular en personas con infección por HIV-1 / Expression of the inflammasome components and its relationship with cardiovascular risk markers in people living with HIV-1

Introducción. La infección por el HIV-1 induce un estado de inflamación crónico en el que participan los inflamasomas. El incremento de los parámetros inflamatorios es mayor en individuos con replicación viral activa que en aquellos con control de la replicación viral. Este proceso desencadena alteraciones metabólicas relacionadas con cambios en el perfil lipídico, lo cual podría incrementar el riesgo de eventos cardiovasculares, incluso en pacientes con terapia antirretroviral. Objetivo. Establecer si existe correlación entre la expresión de los componentes de los inflamasomas y los marcadores de riesgo cardiovascular en individuos con control de la replicación viral y en aquellos con replicación viral activa con terapia antirretroviral o sin ella. Materiales y métodos. Se estudiaron 13 individuos con control de la replicación viral y 40 con replicación viral activa (19 sin terapia antirretroviral y 31 con terapia). Se evaluaron los marcadores clásicos de riesgo cardiovascular y se cuantificó mediante RT-PCR la expresión de los componentes de los inflamasomas (NLRP1, NLRP3, NLRC4, AIM2, ASC, IL-1ß, IL-18 y caspasa-1), TLR2, TLR4, TGF-ß e IL-10. Resultados. Se observó que los pacientes con replicación viral activa y con terapia antirretroviral presentaron un incremento en la expresión de TLR2, TLR4 e IL-18, comparados con los controladores del HIV-1. Además, mostraron grandes valores de triglicéridos y lipoproteína de muy baja densidad (Very Low Density Lipopretein, VLDL), lo que se correlaciona positivamente con la expresión de los componentes de los inflamasomas NLRP1, NLRP3, NLRC4, AIM2, ASC y caspasa-1. Conclusión. El aumento en la expresión de los componentes de los inflamasomas en los individuos con replicación viral activa y con terapia antirretroviral se correlacionó con las concentraciones de triglicéridos y VLDL, lo que sugiere el papel de la activación inmunitaria y la terapia antirretroviral en el riesgo cardiovascular.

Introduction: HIV-1 infection induces a chronic inflammatory state in which inflammasomes participate. The increase in inflammatory parameters is higher in individuals with active viral replication (progressors) than in those with viral control (HIV-1 controllers). This process triggers metabolic alterations related to changes in the lipid profile, which could increase the risk of cardiovascular events, even in patients with antiretroviral therapy. Objective: To establish whether there was a correlation between the expression of inflammasome components and cardiovascular risk markers in HIV-1 controllers and progressors with or without antiretroviral therapy. Materials and methods: We studied 13 HIV-1 controllers and 40 progressors (19 without antiretroviral therapy and 31 with therapy) and evaluated in them classic markers of cardiovascular risk. Using RT-PCR we quantified the expression of inflammasome components (NLRP1, NLRP3, NLRC4, AIM2, ASC, IL-1ß, IL-18, and caspase-1), TLR2, TLR4, TGF-ß, and IL-10. Results: Progressors with antiretroviral therapy had an increased expression of TLR2, TLR4, and IL-18 compared to HIV-1 controllers. They also showed high levels of triglycerides and VLDL, which positively correlated with the expression of the inflammasome components NLRP1, NLRP3, NLRC4, AIM2, ASC, and caspase-1. Conclusion: Progressors receiving antiretroviral therapy exhibited an increased expression of the inflammasome components, which correlated with the levels of triglycerides and VLDL. This supports the role of inflammation in cardiovascular risk during HIV-1 infection.

A short half-life of cccDNA offer or ignite hope for hepatitis B cure under nucleos(t)ide analogues treatment / 中华肝脏病杂志

Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is the template for HBV replication. Currently, there is a lack of therapeutic drugs that directly target cccDNA. Therefore, blocking cccDNA supplements as fast as possible and reducing the existing cccDNA is the key to achieving a complete cure of chronic hepatitis B. Previous studies have suggested that cccDNA had a long half-life, but a recent study showed that it only took a few months to update cycle of cccDNA pool, and its number was much less than previously predicted. In the future, with the advent of new antiviral drugs that can completely inhibit HBV replication, it is expected that the cccDNA pool will be completely cleared due to its supplement complete blockade, so as to achieve virological cure of chronic hepatitis B.

Rational selection of virologic and immunological biomarkers and therapeutic endpoints in the clinical trials of new drugs treating chronic hepatitis B / 中华肝脏病杂志

Hepatitis B virus (HBV) infection remains to be the major cause of chronic liver diseases in China. Since the nucleos(t)ide analogues and pegylated interferon-alpha do not directly target the covalently closed circular DNA (cccDNA) in the nuclei of HBV-infected hepatocytes, those standard-of-care medications cannot efficiently cure the infected hepatocytes and rarely achieve the functional cure of chronic hepatitis B (CHB). Therefore, new antiviral drugs targeting distinct steps of HBV replication and immunotherapeutics reinvigorating antiviral immune responses are urgently needed for the functional cure of CHB. Based on the extensive discussion of the biological and clinical significance of new virologic biomarkers and distinct mechanism of drug candidates currently in clinical development, we propose that the selection of virologic and immunological biomarkers for evaluation of therapeutic efficacy as well as setting the therapeutic endpoints in the clinical trials should be based on the mode of action of investigational drugs. In addition, due to the complexity of CHB pathogenesis, selection of specific subpopulation of CHB patients for the clinical trials of drugs with a specific mode of action should also be considered.

Correlations between genetic polymorphism of IFN-λ family gene and HBV infection, virus replication and clearance / 生物工程学报

Hepatitis B virus (HBV) infection is one of the most serious public health problems. HBV infection could lead to hepatitis B, and even further develop into hepatic cirrhosis and hepatocellular carcinoma. Interferon lambda (IFN-λ) is a member of the interferon (IFN) family and an important cytokine for antiviral defense. There are four members in IFN-λ family, including IFN-λ1, IFN-λ2, IFN-λ3, and IFN-λ4. The genetic polymorphisms in the IFN-λ genes are associated with HBV replication and treatment response of HBV patients. In this review, we summarized the roles of genetic polymorphisms of the IFN-λ genes played in HBV infection, disease progression and treatment, with the aim to better understand their function. This review could serve as a reference for the HBV prevention and treatment of HBV patients, as well as for future clinical usage.

The nucleocapsid protein of rice stripe virus in cell nuclei of vector insect regulates viral replication

Rice stripe virus (RSV) transmitted by the small brown planthopper causes severe rice yield losses in Asian countries. Although viral nuclear entry promotes viral replication in host cells, whether this phenomenon occurs in vector cells remains unknown. Therefore, in this study, we systematically evaluated the presence and roles of RSV in the nuclei of vector insect cells. We observed that the nucleocapsid protein (NP) and viral genomic RNAs were partially transported into vector cell nuclei by utilizing the importin α nuclear transport system. When blocking NP nuclear localization, cytoplasmic RSV accumulation significantly increased. In the vector cell nuclei, NP bound the transcription factor YY1 and affected its positive regulation to FAIM. Subsequently, decreased FAIM expression triggered an antiviral caspase-dependent apoptotic reaction. Our results reveal that viral nuclear entry induces completely different immune effects in vector and host cells, providing new insights into the balance between viral load and the immunity pressure in vector insects.

Bixinoids Derived from Bixa orellana as a Potential Zika Virus Inhibitor Using Molecular Simulations. Antiviral Effect on the Zika Virus of Bixinoids

Abstract Zika fever is a viral infection of great relevance in public health, especially in tropic regions, in which there is a predominance of mosquitoes of the genus Aedes, vectors of the disease. Microcephaly in neonatal children and Guillain-Barré syndrome in adults can be caused by the action of the Zika virus (ZIKV). Non-structural proteins, such as NS2B, NS3 and NS5, are important pharmacological targets, due to their action in the life cycle. The absence of anti-Zika drugs raises new research, including prospecting for natural products. This work investigated the in silico antiviral activity of bixin and six other derived molecules against the Zika viral proteins NS2B-NS3 and NS5. The optimized structure was subjected to molecular docking to characterize the interaction between bixinoids and ZIKV non-structural proteins, where significant interactions were observed with amino acid residues in the catalytic site in each enzyme. These results suggest that bixin and ethyl bixin has the potential to interfere with the enzymatic activity of NS2B, NS3 and NS5, thus being an indication of being a promising anti-Zika agent.

Las variantes de SARS-CoV-2 y la llamada resistencia a las vacunas / SARS-CoV-2 variants and the so-called resistance to vaccines

Resumen Los virus ARN, excepto los retrovirus, se replican por acción de una ARN polimerasa ARN-dependiente que carece de exonucleasa correctora y, en consecuencia, en cada replicación puede co meter errores. Así se originan mutantes que, según su menor o mayor fitness, se extinguen o bien prosperan y originan variantes que escapan al sistema inmune. Las mutaciones de SARS-CoV-2 más importantes son las que alteran la proteína viral S, porque ella tiene la llave de ingreso del virus a la célula humana. Cuanto más se replican los virus, más mutan, y se hace más probable que aparezcan variantes resistentes dominantes. En esos casos, se requerirá una aplicación más estricta de las medidas de protección de la comunidad. Las vacunas y los anticuerpos policlonales, que inducen una respuesta dirigida hacia toda la proteína S, mantendrían protec ción efectiva contra las variantes del SARS-CoV-2. Además, las vacunas inducirían una mayor respuesta de células T helper y citotóxicas, lo que puede ser un biomarcador de protección. En áreas densamente pobladas con escasas medidas de protección, el virus se difunde libremente y aumenta la probabilidad de mutaciones de escape. India y Manaos ejemplifican esa situación. La evolución natural selecciona las mutantes que se repro ducen con mayor eficiencia sin eliminar al huésped, lo que facilita la propagación. En cambio, la circulación de virus de alta virulencia y letalidad (Ebola, hantavirus), que eliminan al huésped, se circunscribe a determinadas áreas geográficas, sin mayor difusión. Por lo tanto, sería esperable que SARS-CoV-2 evolucione a variantes más infecciosas y menos virulentas.

Abstract RNA viruses (except retroviruses) replicate by the action of an RNA-dependent RNA polymerase, which lacks a proofreading exo nuclease and, consequently, errors may occur in each replication giving place to viral mutants. Depending on their fitness, these mutants either become extinct or thrive, spawning variants that escape the immune system. The most important SARS-CoV-2 mutations are those that alter the amino acid sequence in the viral S protein because this protein holds the key for the virus to enter the human cell. The more viruses replicate, the more they mutate, and the more likely it is that dominant resistant variants will appear. In such cases, more stringent measures for community protection will be required. Vaccines and polyclonal antibodies, which induce a response directed towards several sites along the S protein, would maintain effective protection against SARS-CoV-2 vari ants. Furthermore, vaccines appear to induce an increased helper and cytotoxic T-cell response, which may also be a biomarker of protection. In densely populated areas with insufficient protection measures, the virus spreads freely, thus increasing the likelihood of generating escape mutants. India and Manaus exemplify this situation. Natural evolution selects the mutants that multiply most efficiently without eliminating the host, thus facilitating their spread. Contrastingly, the circulation of viruses of high virulence and lethality (Ebola, hantavirus) that elimi nate the host remain limited to certain geographic areas, without further dissemination. Therefore, it would be expected that SARS-CoV-2 will evolve into more infectious and less virulent variants.

Host metabolism dysregulation and cell tropism identification in human airway and alveolar organoids upon SARS-CoV-2 infection

The coronavirus disease 2019 (COVID-19) pandemic is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is spread primary via respiratory droplets and infects the lungs. Currently widely used cell lines and animals are unable to accurately mimic human physiological conditions because of the abnormal status of cell lines (transformed or cancer cells) and species differences between animals and humans. Organoids are stem cell-derived self-organized three-dimensional culture in vitro and model the physiological conditions of natural organs. Here we showed that SARS-CoV-2 infected and extensively replicated in human embryonic stem cells (hESCs)-derived lung organoids, including airway and alveolar organoids which covered the complete infection and spread route for SARS-CoV-2 within lungs. The infected cells were ciliated, club, and alveolar type 2 (AT2) cells, which were sequentially located from the proximal to the distal airway and terminal alveoli, respectively. Additionally, RNA-seq revealed early cell response to virus infection including an unexpected downregulation of the metabolic processes, especially lipid metabolism, in addition to the well-known upregulation of immune response. Further, Remdesivir and a human neutralizing antibody potently inhibited SARS-CoV-2 replication in lung organoids. Therefore, human lung organoids can serve as a pathophysiological model to investigate the underlying mechanism of SARS-CoV-2 infection and to discover and test therapeutic drugs for COVID-19.

Hepatitis B core-related antigen reflects viral replication and protein production in chronic hepatitis B patients / 中华医学杂志(英文版)

BACKGROUND@#Hepatitis B core-related antigen (HBcrAg) is a promising disease-monitoring marker for chronic hepatitis B (CHB). We investigated correlations between HBcrAg with antiviral efficacy and virological and histological variables.@*METHODS@#One hundred and forty-five CHB patients from the mainland of China between August 2013 and September 2016 who underwent liver biopsy received entecavir therapy and had paired liver biopsy at 78 weeks. We analyzed correlations between HBcrAg and virological and histological variables in hepatitis B e antigen (HBeAg)-positive and HBeAg-negative patients. We also explored the predictors of HBeAg loss after 78 weeks of antiviral therapy. Pearson correlation analysis and logistic forward stepwise regression were the main statistic methods.@*RESULTS@#HBeAg-positive patients (n = 93) had higher baseline HBcrAg (median 7.4 vs. 5.3 log10 U/mL P < 0.001) and greater HBcrAg declines (median 1.6 vs. 0.9 log10 U/mL P = 0.007) than HBeAg-negative patients after 78 weeks of therapy. At baseline, HBcrAg correlated with hepatitis B virus (HBV) DNA in both HBeAg-positive (r = 0.641, P < 0.001) and -negative patients (r = 0.616, P < 0.001), with hepatitis B surface antigen (HBsAg) in HBeAg-positive patients (r = 0.495, P < 0.001), but not with anti-hepatitis B virus core antibody (anti-HBc). Weak correlations existed between HBcrAg, histology activity index (HAI; r = 0.232, P = 0.025), and Ishak fibrosis score (r = -0.292, P = 0.005) in HBeAg-positive patients. At 78 weeks, significant correlations existed only between HBcrAg and anti-HBc in HBeAg-positive (r = -0.263, P = 0.014) and HBeAg-negative patients (r = -0.291, P = 0.045). Decreased HBcrAg significantly correlated with reduced HBV DNA (r = 0.366, P = 0.001; r = 0.626, P < 0.001) and HBsAg (r = 0.526, P = 0.001; r = 0.289, P = 0.044) in HBeAg-positive and -negative patients, respectively, and with reduced HAI in HBeAg-positive patients (r = 0.329, P = 0.001). Patients with HBeAg loss (n = 29) showed a larger reduction in HBcrAg than those without (median 2.3 vs. 1.3 log10 U/mL, P = 0.001). In multivariate analysis, decreased HBcrAg was an independent predictor of HBeAg loss (P = 0.005).@*CONCLUSIONS@#HBcrAg reflects viral replication and protein production. Decreased HBcrAg could predict HBeAg loss after antiviral therapy.@*TRIAL REGISTRATION@#Clinical Trials.gov: NCT01962155; https://www.clinicaltrials.gov/ct2/show/NCT01962155?term=NCT01962155&draw=2&rank=1.

Steroidal saponins from the roots of Solanum sisymbriifolium Lam. (Solanaceae) have inhibitory activity against dengue virus and yellow fever virus

Dengue is the most important arthropod-borne viral disease worldwide. Infection with any of the four dengue virus (DENV) serotypes can be asymptomatic or lead to disease with clinical symptoms ranging from undifferentiated and self-limiting fever to severe dengue disease, which can be fatal in some cases. Currently, no specific antiviral compound is available for treating DENV. The aim of this study was to identify compounds in plants from Paraguayan folk medicine with inhibitory effects against DENV. We found high virucidal activity (50% maximal effective concentration (EC50) value of 24.97 µg/mL) against DENV-2 in the ethanolic extract of the roots of Solanum sisymbriifolium Lam. (Solanaceae) without an evident cytotoxic effect on Vero E6 cells. Three saponins isolated from the root extract showed virucidal effects (EC50 values ranging from 24.9 to 35.1 µg/mL) against DENV-2. Additionally, the saponins showed inhibitory activity against yellow fever virus (EC50 values ranging from 126 to 302.6 µg/mL), the prototype virus of the Flavivirus genus, suggesting that they may also be effective against other members of this genus. Consequently, these saponins may be lead compounds for the development of antiviral agents.

Patogenia de la infección por SARS-CoV-2 / Pathogenesis of SARS-CoV-2 infection

Covid-19 is an infectious disease whose etiological agent called SARS-CoV-2. It has a high contagion rate, high morbidity and mortality, and potential multi-organ compromise. Its main route of infection is by droplets, however, the infection can be acquired by other routes such as aerosols, fecal-oral and contact with fomites. Although the immune response is essential for defense against any infection, in severe Covid-19 infection, a dysregulation of the immune system occurs, which leads to marked increases of cytokines and the consequent systemic inflammatory state. Inflammation, infection, and viral shedding can compromise the lungs, blood vessels, brain, gastrointestinal (GI) tract, kidneys, heart, and liver, ultimately leading to multiple organ dysfunction and failure. (AU)

COVID-19: enfoque básico para entender sus tratamientos / COVID-19: a basic approach to understanding potential treatments

Resumen El virus SARS-CoV-2 ha sido identificado como el agente patológico causante de la pandemia de COVID-19. Aun cuando no se cuenta con un tratamiento estándar, se han probado antivirales como remdesivir y otros fármacos como cloroquina e ivermectina, que interfieren con la replicación del virus. También se han intentado algunas estrategias encaminadas a disminuir los mecanismos inmunitarios, como el uso de tocilizumab y antioxidantes naturales. Los fármacos relacionados con el sistema renina-angiotensina han resultado controversiales. Aún se debe estudiar con detalle los mecanismos de patogenicidad, así como los tratamientos controlados para proponer alguna opción terapéutica viable que evite la entrada y replicación del virus o que aumente los sistemas inmunitarios del huésped.

Abstract SARS-CoV-2 virus has been identified as the causative agent of the COVID-19 pandemic. Even when no standard treatment is available, antivirals such as remdesivir and other drugs such as chloroquine and ivermectin, which interfere with viral replication, have been assayed. Some strategies aimed to reduce immune mechanisms, such as the use of tocilizumab and natural antioxidants, have also been tested. The use of drugs related to the renin-angiotensin system has been controversial. Pathogenicity mechanisms, as well as controlled treatments, still have to be studied in detail in order to propose a viable therapeutic option that prevents the entry and replication of the virus or enhances the host immune system.