An ISG15-Based High-Throughput Screening Assay for Identification and Characterization of SARS-CoV-2 Inhibitors Targeting Papain-like Protease.

Emergence of newer variants of SARS-CoV-2 underscores the need for effective antivirals to complement the vaccination program in managing COVID-19. The multi-functional papain-like protease (PLpro) of SARS-CoV-2 is an essential viral protein that not only regulates the viral replication but also modulates the host immune system, making it a promising therapeutic target. To this end, we developed an in vitro interferon stimulating gene 15 (ISG15)-based Förster resonance energy transfer (FRET) assay and screened the National Cancer Institute (NCI) Diversity Set VI compound library, which comprises 1584 small molecules.

Broad-Spectrum Small-Molecule Inhibitors Targeting the SAM-Binding Site of Flavivirus NS5 Methyltransferase.

Flavivirus infections, such as those caused by dengue virus (DENV), West Nile virus (WNV), yellow fever virus (YFV), and Zika virus (ZIKV), pose a rising threat to global health. There are no FDA-approved drugs for flaviviruses, although a small number of flaviviruses have vaccines. For flaviviruses or unknown viruses that may appear in the future, it is particularly desirable to identify broad-spectrum inhibitors.

A universal fluorescence polarization high throughput screening assay to target the SAM-binding sites of SARS-CoV-2 and other viral methyltransferases.

SARS-CoV-2 has caused a global pandemic with significant humanity and economic loss since 2020. Currently, only limited options are available to treat SARS-CoV-2 infections for vulnerable populations. In this study, we report a universal fluorescence polarization (FP)-based high throughput screening (HTS) assay for SAM-dependent viral methyltransferases (MTases), using a fluorescent SAM-analogue, FL-NAH.

Allosteric inhibitors of the main protease of SARS-CoV-2.

SARS-CoV-2 has raised the alarm to search for effective therapy for this virus. To date several vaccines have been approved but few available drugs reported recently still need approval from FDA. Remdesivir was approved for emergency use only.

Antiviral Agents against Flavivirus Protease: Prospect and Future Direction.

Flaviviruses cause a significant amount of mortality and morbidity, especially in regions where they are endemic. A recent example is the outbreak of Zika virus throughout the world. Development of antiviral drugs against different viral targets is as important as the development of vaccines.

Targeting Crucial Host Factors of SARS-CoV-2.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide since its first incidence in Wuhan, China, in December 2019. Although the case fatality rate of COVID-19 appears to be lower than that of SARS and Middle East respiratory syndrome (MERS), the higher transmissibility of SARS-CoV-2 has caused the total fatality to surpass other viral diseases, reaching more than 1 million globally as of October 6, 2020. The rate at which the disease is spreading calls for a therapy that is useful for treating a large population.

Methylene blue is a potent and broad-spectrum inhibitor against Zika virus and .

Many flaviviruses including the Dengue virus (DENV), Zika virus (ZIKV), West Nile virus, Yellow Fever virus, and Japanese encephalitis virus are significant human pathogens, unfortunately without any specific therapy. Here, we demonstrate that methylene blue, an FDA-approved drug, is a broad-spectrum and potent antiviral against Zika virus and Dengue virus both and . We found that methylene blue can considerably inhibit the interactions between viral protease NS3 and its NS2B co-factor, inhibit viral protease activity, inhibit viral growth, protect 3D mini-brain organoids from ZIKV infection, and reduce viremia in a mouse model.

Prospect of SARS-CoV-2 spike protein: Potential role in vaccine and therapeutic development.

The recent outbreak of the betacoronavirus SARS-CoV-2 has become a significant concern to public health care worldwide. As of August 19, 2020, more than 22,140,472 people are infected, and over 781,135 people have died due to this deadly virus. In the USA alone, over 5,482,602 people are currently infected, and more than 171,823 people have died.

Effect of SUMO-SIM Interaction on the ICP0-Mediated Degradation of PML Isoform II and Its Associated Proteins in Herpes Simplex Virus 1 Infection.

ND10 nuclear bodies, as part of the intrinsic defenses, impose repression on incoming DNA. Infected cell protein 0 (ICP0), an E3 ubiquitin ligase of herpes simplex virus 1 (HSV-1), can derepress viral genes by degrading ND10 organizers to disrupt ND10. These events are part of the initial tug of war between HSV-1 and host, which determines the ultimate outcome of infection.

Temporal Analysis of the Nuclear-to-cytoplasmic Translocation of a Herpes Simplex Virus 1 Protein by Immunofluorescent Confocal Microscopy.

Infected cell protein 0 (ICP0) of herpes simplex virus 1 (HSV-1) is an immediate early protein containing a RING-type E3 ubiquitin ligase. It is responsible for the proteasomal degradation of host restrictive factors and the subsequent viral gene activation. ICP0 contains a canonical nuclear localization sequence (NLS).

Characterization of Elements Regulating the Nuclear-to-Cytoplasmic Translocation of ICP0 in Late Herpes Simplex Virus 1 Infection.

Infected cell protein 0 (ICP0) of herpes simplex virus 1 (HSV-1) is an immediate early protein containing a RING-type E3 ubiquitin ligase. It targets several host factors for proteasomal degradation and subsequently activates viral expression. ICP0 has a nuclear localization sequence and functions in the nucleus early during infection.

A Tale of Two PMLs: Elements Regulating a Differential Substrate Recognition by the ICP0 E3 Ubiquitin Ligase of Herpes Simplex Virus 1.

Unlabelled: Infected cell protein 0 (ICP0) of herpes simplex virus 1 (HSV-1) is an α gene product required for viral replication at low multiplicities of infection. Upon entry, nuclear domain 10 (ND10) converges at the incoming DNA and represses viral gene expression. ICP0 contains a RING-type E3 ubiquitin ligase that degrades the ND10 organizer PML and disperses ND10 to alleviate the repression.

Heterologous Immunity between Adenoviruses and Hepatitis C Virus: A New Paradigm in HCV Immunity and Vaccines.

Adenoviruses (Ad) are commonly used as vectors for gene therapy and/or vaccine delivery. Recombinant Ad vectors are being tested as vaccines for many pathogens. We have made a surprising observation that peptides derived from various hepatitis C virus (HCV) antigens contain extensive regions of homology with multiple adenovirus proteins, and conclusively demonstrate that adenovirus vector can induce robust, heterologous cellular and humoral immune responses against multiple HCV antigens.

Immunization with Recombinant Adenoviral Vectors Expressing HCV Core or F Proteins Leads to T Cells with Reduced Effector Molecules Granzyme B and IFN-γ: A Potential New Strategy for Immune Evasion in HCV Infection.

Multispecific, broad, and potent T cell responses have been correlated with viral clearance in hepatitis C virus (HCV) infection. However, the majority of infected patients develop chronic infection, suggesting that natural infection mostly leads to development of inefficient T cell immunity. Multiple mechanisms of immune modulation and evasion have been shown in HCV infection through various investigations.

Co-incubation with core proteins of HBV and HCV leads to modulation of human dendritic cells.

Hepatitis B and C (HBV and HCV) are hepatotropic viruses in humans with approximately 350 and 170 million chronic carriers respectively. Since both viruses have similar modes of transmission, many people are co-infected. Co-infection is common in intravenous drug users, HIV-positive individuals, and transplant recipients.

Recombinant adenoviral vector expressing HCV NS4 induces protective immune responses in a mouse model of Vaccinia-HCV virus infection: a dose and route conundrum.

Hepatitis C virus (HCV) leads to chronic infection in the majority of infected patients presumably due to failure or inefficiency of the immune responses generated. Both antibody and cellular immune responses have been suggested to be important in viral clearance. Non-replicative adenoviral vectors expressing antigens of interest are considered as attractive vaccine vectors for a number of pathogens.

Alternate reading frame protein (F protein) of hepatitis C virus: paradoxical effects of activation and apoptosis on human dendritic cells lead to stimulation of T cells.

Hepatitis C virus (HCV) leads to chronic infection in the majority of infected individuals due to lack, failure, or inefficiency of generated adaptive immune responses. In a minority of patients, acute infection is followed by viral clearance. The immune correlates of viral clearance are not clear yet but have been extensively investigated, suggesting that multispecific and multifunctional cellular immunity is involved.

Genetic and functional analysis of HIV-1 Rev Responsive Element (RRE) sequences from North-India.

HIV-1 Rev protein regulates the expression of HIV-1 transcripts by binding to a highly structured stem loop structure called the Rev Responsive Element (RRE) present in the genomic and partially spliced RNAs. Genetic variation in this structure is likely to affect binding of Rev protein and ultimately overall gene expression and replication. We characterized RRE sequences from 13 HIV-1 infected individuals from North India which also included two mother-child pairs following vertical transmission.

Global HIV-1 molecular epidemiology with special reference to genetic analysis of HIV-1 subtypes circulating in North India: functional and pathogenic implications of genetic variation.

HIV-1 displays extensive genetic diversity globally which poses challenge in designing a suitable antigen/immunogen to provoke desired protective immune response in host. HIV-1 mediated pathogenesis is complex and involves host genes, virus genes and other factors. A number of genetic subtypes have been identified based on sequence variations, largely in envelope region.

Dissecting the functional role of polyketide synthases in Dictyostelium discoideum: biosynthesis of the differentiation regulating factor 4-methyl-5-pentylbenzene-1,3-diol.

Dictyostelium discoideum exhibits the largest repository of polyketide synthase (PKS) proteins of all known genomes. However, the functional relevance of these proteins in the biology of this organism remains largely obscure. On the basis of computational, biochemical, and gene expression studies, we propose that the multifunctional Dictyostelium PKS (DiPKS) protein DiPKS1 could be involved in the biosynthesis of the differentiation regulating factor 4-methyl-5-pentylbenzene-1,3-diol (MPBD).