Viral Resistance Analyses From the Remdesivir Phase 3 Adaptive COVID-19 Treatment Trial-1 (ACTT-1).

Background: Remdesivir is approved for treatment of coronavirus disease 2019 (COVID-19) in nonhospitalized and hospitalized adult and pediatric patients. Here we present severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) resistance analyses from the phase 3 ACTT-1 randomized placebo-controlled trial conducted in adult participants hospitalized with COVID-19.

Methods: Swab samples were collected at baseline and longitudinally through day 29.

A Small Molecule RIG-I Agonist Serves as an Adjuvant to Induce Broad Multifaceted Influenza Virus Vaccine Immunity.

Retinoic acid-inducible gene I (RIG-I) is essential for activating host cell innate immunity to regulate the immune response against many RNA viruses. We previously identified that a small molecule compound, KIN1148, led to the activation of IFN regulatory factor 3 (IRF3) and served to enhance protection against influenza A virus (IAV) A/California/04/2009 infection. We have now determined direct binding of KIN1148 to RIG-I to drive expression of IFN regulatory factor 3 and NF-κB target genes, including specific immunomodulatory cytokines and chemokines.

Duration of viral infectiousness and correlation with symptoms and diagnostic testing in non-hospitalized adults during acute SARS-CoV-2 infection: A longitudinal cohort study.

Background: Guidelines for SARS-CoV-2 have relied on limited data on duration of viral infectiousness and correlation with COVID-19 symptoms and diagnostic testing.

Methods: We enrolled ambulatory adults with acute SARS-CoV-2 infection and performed serial measurements of COVID-19 symptoms, nasal swab viral RNA, nucleocapsid (N) and spike (S) antigens, and replication-competent SARS-CoV-2 by viral growth in culture. We determined average time from symptom onset to a first negative test result and estimated risk of infectiousness, as defined by positive viral growth in culture.

Immune Correlates of Protection From West Nile Virus Neuroinvasion and Disease.

Background: A challenge to the design of improved therapeutic agents and prevention strategies for neuroinvasive infection and associated disease is the lack of known natural immune correlates of protection. A relevant model to study such correlates is offered by the Collaborative Cross (CC), a panel of recombinant inbred mouse strains that exhibit a range of disease manifestations upon infection.

Methods: We performed an extensive screen of CC-F1 lines infected with West Nile virus (WNV), including comprehensive immunophenotyping, to identify groups of lines that exhibited viral neuroinvasion or neuroinvasion with disease and lines that remained free of WNV neuroinvasion and disease.

Interferon-stimulated genes: new platforms and computational approaches.

Interferon-stimulated genes (ISGs) are the effectors of interferon (IFN) actions and play major roles in innate immune defense against microbial infection. During virus infection, ISGs impart antiviral actions to control virus replication and spread but can also contribute to disease pathology if their expression is unchecked. Antiviral ISGs have been identified by a variety of biochemical, genetic, and virologic methods.

RNA PAMPs as Molecular Tools for Evaluating RIG-I Function in Innate Immunity.

Pathogen recognition receptors (PRR)s and their cognate pathogen-associated molecular pattern (PAMP) represent the basis of innate immune activation and immune response induction driven by the host-pathogen interaction that occurs during microbial infection in humans and other animals. For RNA virus infection such as hepatitis C virus (HCV) and others, specific motifs within viral RNA mark it as nonself and visible to the host as a PAMP through interaction with RIG-I-like receptors including retinoic inducible gene-I (RIG-I). Here, we present methods for producing and using HCV PAMP RNA as a molecular tool to study RIG-I and its signaling pathway, both in vitro and in vivo, in innate immune regulation.

Oas1b-dependent Immune Transcriptional Profiles of West Nile Virus Infection in the Collaborative Cross.

The oligoadenylate-synthetase () gene locus provides innate immune resistance to virus infection. In mouse models, variation in the gene influences host susceptibility to flavivirus infection. However, the impact of variation on overall innate immune programming and global gene expression among tissues and in different genetic backgrounds has not been defined.

A small-molecule IRF3 agonist functions as an influenza vaccine adjuvant by modulating the antiviral immune response.

Vaccine adjuvants are essential to drive a protective immune response in cases where vaccine antigens are weakly immunogenic, where vaccine antigen is limited, or where an increase in potency is needed for a specific population, such as the elderly. To discover novel vaccine adjuvants, we used a high-throughput screen (HTS) designed to identify small-molecule agonists of the RIG-I-like receptor (RLR) pathway leading to interferon regulatory factor 3 (IRF3) activation. RLRs are a group of cytosolic pattern-recognition receptors that are essential for the recognition of viral nucleic acids during infection.

Transcriptional profiles of WNV neurovirulence in a genetically diverse Collaborative Cross population.

West Nile Virus (WNV) is a mosquito-transmitted virus from the Flaviviridae family that causes fever in 1 in 5 infected people. WNV can also become neuro-invasive and cross the blood-brain barrier leading to severe neurological symptoms in a subset of WNV infected individuals [1]. WNV neuro-invasion is believed to be influenced by a number of factors including host genetics.

Identifying protective host gene expression signatures within the spleen during West Nile virus infection in the collaborative cross model.

Flaviviruses are hematophagous arthropod-viruses that pose global challenges to human health. Like Zika virus, West Nile Virus (WNV) is a flavivirus for which no approved vaccine exists [1]. The role host genetics play in early detection and response to WNV still remains largely unexplained.

A Mouse Model of Chronic West Nile Virus Disease.

Infection with West Nile virus (WNV) leads to a range of disease outcomes, including chronic infection, though lack of a robust mouse model of chronic WNV infection has precluded identification of the immune events contributing to persistent infection. Using the Collaborative Cross, a population of recombinant inbred mouse strains with high levels of standing genetic variation, we have identified a mouse model of persistent WNV disease, with persistence of viral loads within the brain. Compared to lines exhibiting no disease or marked disease, the F1 cross CC(032x013)F1 displays a strong immunoregulatory signature upon infection that correlates with restraint of the WNV-directed cytolytic response.

Targeting Innate Immunity for Antiviral Therapy through Small Molecule Agonists of the RLR Pathway.

Unlabelled: The cellular response to virus infection is initiated when pathogen recognition receptors (PRR) engage viral pathogen-associated molecular patterns (PAMPs). This process results in induction of downstream signaling pathways that activate the transcription factor interferon regulatory factor 3 (IRF3). IRF3 plays a critical role in antiviral immunity to drive the expression of innate immune response genes, including those encoding antiviral factors, type 1 interferon, and immune modulatory cytokines, that act in concert to restrict virus replication.

Pushing to a cure by harnessing innate immunity against hepatitis C virus.

Hepatitis C virus (HCV) causes 350,000 deaths and infects at least 3million people worldwide every year. Currently no vaccine has been developed. Direct-acting antiviral (DAA) drugs with high efficacy for suppressing HCV infection have recently been introduced into the clinic.

Systems biology analyses to define host responses to HCV infection and therapy.

While 170 million people worldwide are chronically infected with HCV, the response rate to the current treatment regimens of pegylated IFN-α (IFN) in combination with ribavirin is only approximately 55 % of all HCV patients undergoing therapy. This IFN-based therapy is now slated to serve as the backbone for future combination therapeutics involving direct-acting antiviral compounds, including HCV protease inhibitors, viral polymerase inhibitors, and other small molecules. It is essential that the application of IFN be improved for overall enhancement of therapy outcome to effectively cure HCV infection.

RIG-I like receptors in antiviral immunity and therapeutic applications.

The RNA helicase family of RIG-I-like receptors (RLRs) is a key component of host defense mechanisms responsible for detecting viruses and triggering innate immune signaling cascades to control viral replication and dissemination. As cytoplasm-based sensors, RLRs recognize foreign RNA in the cell and activate a cascade of antiviral responses including the induction of type I interferons, inflammasome activation, and expression of proinflammatory cytokines and chemokines. This review provides a brief overview of RLR function, ligand interactions, and downstream signaling events with an expanded discussion on the therapeutic potential of targeting RLRs for immune stimulation and treatment of virus infection.

Integrated proteomic analysis of human cancer cells and plasma from tumor bearing mice for ovarian cancer biomarker discovery.

Background: The complexity of the human plasma proteome represents a substantial challenge for biomarker discovery. Proteomic analysis of genetically engineered mouse models of cancer and isolated cancer cells and cell lines provide alternative methods for identification of potential cancer markers that would be detectable in human blood using sensitive assays. The goal of this work is to evaluate the utility of an integrative strategy using these two approaches for biomarker discovery.

Proteomic analysis of ovarian cancer cells reveals dynamic processes of protein secretion and shedding of extra-cellular domains.

Background: Elucidation of the repertoire of secreted and cell surface proteins of tumor cells is relevant to molecular diagnostics, tumor imaging and targeted therapies. We have characterized the cell surface proteome and the proteins released into the extra-cellular milieu of three ovarian cancer cell lines, CaOV3, OVCAR3 and ES2 and of ovarian tumor cells enriched from ascites fluid.

Methodology And Findings: To differentiate proteins released into the media from protein constituents of media utilized for culture, cells were grown in the presence of [(13)C]-labeled lysine.

A mouse to human search for plasma proteome changes associated with pancreatic tumor development.

Background: The complexity and heterogeneity of the human plasma proteome have presented significant challenges in the identification of protein changes associated with tumor development. Refined genetically engineered mouse (GEM) models of human cancer have been shown to faithfully recapitulate the molecular, biological, and clinical features of human disease. Here, we sought to exploit the merits of a well-characterized GEM model of pancreatic cancer to determine whether proteomics technologies allow identification of protein changes associated with tumor development and whether such changes are relevant to human pancreatic cancer.

Overexpression of EPHA2 receptor destabilizes adherens junctions via a RhoA-dependent mechanism.

EPHA2 receptor tyrosine kinase is overexpressed in several human cancer types and promotes malignancy. However, the mechanisms by which EPHA2 promotes tumor progression are not completely understood. Here we report that overexpression of a wild-type EPHA2, but not a signaling-defective cytoplasmic truncation mutant (DeltaC), in human mammary epithelial cells weakens E-cadherin-mediated cell-cell adhesion.

EphA2 receptor tyrosine kinase as a promising target for cancer therapeutics.

Eph receptors are a unique family of receptor tyrosine kinases (RTK) that play critical roles in embryonic patterning, neuronal targeting, and vascular development during normal embryogenesis. Eph RTKs and their ligands, the ephrins, are also frequently overexpressed in a variety of cancers and tumor cell lines. In particular, one family member, EphA2, is overexpressed in breast, prostate, lung, and colon cancers.

A core function for p120-catenin in cadherin turnover.

p120-catenin stabilizes epithelial cadherin (E-cadherin) in SW48 cells, but the mechanism has not been established. Here, we show that p120 acts at the cell surface to control cadherin turnover, thereby regulating cadherin levels. p120 knockdown by siRNA expression resulted in dose-dependent elimination of epithelial, placental, neuronal, and vascular endothelial cadherins, and complete loss of cell-cell adhesion.

A novel role for p120 catenin in E-cadherin function.

Indirect evidence suggests that p120-catenin (p120) can both positively and negatively affect cadherin adhesiveness. Here we show that the p120 gene is mutated in SW48 cells, and that the cadherin adhesion system is impaired as a direct consequence of p120 insufficiency. Restoring normal levels of p120 caused a striking reversion from poorly differentiated to cobblestone-like epithelial morphology, indicating a crucial role for p120 in reactivation of E-cadherin function.