Using genome-wide small interfering RNA (siRNA) screens for poliovirus, influenza A virus and rotavirus, we validated the top 6 gene hits PV, RV or IAV to search for host genes that when knocked-down (KD) enhanced virus permissiveness and replication over wild type Vero cells or HEp-2 cells. The enhanced virus replication was tested for 12 viruses and ranged from 2-fold to >1000-fold. There were variations in virus-specific replication (strain differences) across the cell lines examined. Some host genes (CNTD2, COQ9, GCGR, NDUFA9, NEU2, PYCR1, SEC16G, SVOPL, ZFYVE9, and ZNF205) showed that KD resulted in enhanced virus replication. These findings advance platform-enabling vaccine technology, the creation of diagnostic cells substrates, and are informative about the host mechanisms that affect virus replication in mammalian cells.

Influenza epidemics result in morbidity and mortality each year. Vaccines are the most effective preventive measure but require annual reformulation, since a mismatch of vaccine strains can result in vaccine failure.

Avian influenza (AI) viruses cause infection in birds and humans. Several H5N1 and H7N9 variants are highly pathogenic avian influenza (HPAI) viruses. H5N1 is a highly infectious bird virus infecting primarily poultry, but unlike other AIs, H5N1 also infects mammals and transmits to humans with a case fatality rate above 40%. Similarly, H7N9 can infect humans, with a case fatality rate of over 40%. Since 1996, there have been several HPAI outbreaks affecting humans, emphasizing the need for safe and effective antivirals. We show that probenecid potently inhibits H5N1 and H7N9 replication in prophylactically or therapeutically treated A549 cells and normal human broncho-epithelial (NHBE) cells, and H5N1 replication in VeroE6 cells and mice.

Immunization with COVID-19 vaccines has greatly reduced COVID-19-related deaths and hospitalizations from SARS-CoV-2 infection, but waning immunity and the emergence of variants capable of immune escape indicate the need for annual vaccine updates or development of different SARS-CoV-2 vaccine platforms. Parainfluenza virus 5 (PIV5)-vectored intranasal COVID-19 vaccine with the ancestral spike (S) protein (CVXGA1) has been shown to be a promising next-generation COVID-19 vaccine preclinically and is currently being evaluated in humans. This work investigates the immunogenicity and efficacy of CVXGA1 and other PIV5-vectored vaccine candidates expressing additional SARS-CoV-2 nucleoprotein (N) antigen or SARS-CoV-2 variant S proteins of beta, delta, gamma, and omicron variants against homologous and heterologous challenges in hamsters. A single intranasal dose of CVXGA1 induces neutralizing antibodies (nAbs) against SARS-CoV-2 WA1 (ancestral), delta variant, and omicron variant and protects against both homologous and heterologous virus challenges. Compared to mRNA COVID-19 vaccine, neutralizing antibody titers induced by CVXGA1 were well maintained over time. When administered as a booster following two doses of an mRNA COVID-19 vaccine, PIV5-vectored vaccines expressing the S protein from WA1 (CVXGA1), delta, or omicron variants generate higher levels of cross-reactive nAbs than three doses of mRNA vaccine. Our data indicate that an intranasal PIV5-vectored COVID-19 vaccine can serve as a booster vaccine against emerging variants. IMPORTANCE: With emerging new variants of concern (VOC), SARS-CoV-2 continues to be a major threat to human health. Approved COVID-19 vaccines have been less effective against these emerging VOCs. This work demonstrates the protective efficacy and strong boosting effect of an intranasal viral-vectored vaccine against SARS-CoV-2 variants in hamsters. Our intranasal vaccine can act as an effective booster for individuals already 58 vaccinated against SARS-CoV-2.

Influenza viruses cause respiratory tract infections and substantial health concerns. Infection may result in mild to severe respiratory disease associated with morbidity and some mortality. Several anti-influenza drugs are available, but these agents target viral components and are susceptible to drug resistance. There is a need for new antiviral drug strategies that include repurposing of clinically approved drugs. Drugs that target cellular machinery necessary for influenza virus replication can provide a means for inhibiting influenza virus replication. We used RNA interference screening to identify key host cell genes required for influenza replication, and then FDA-approved drugs that could be repurposed for targeting host genes. We examined the effects of Clopidogrel and Triamterene to inhibit A/WSN/33 (EC₅₀5.84 uM and 31.48 uM, respectively), A/CA/04/09 (EC₅₀6.432 uM and 3.32 uM, respectively), and B/Yamagata/16/1988 (EC₅₀0.28 uM and 0.11 uM, respectively) replication. Clopidogrel and Triamterene provide a druggable approach to influenza treatment across multiple strains and subtypes.

Influenza virus causes seasonal epidemics and sporadic pandemics resulting in morbidity, mortality, and economic losses worldwide. Understanding how to regulate influenza virus replication is important for developing vaccine and therapeutic strategies. Identifying microRNAs (miRs) that affect host genes used by influenza virus for replication can support an antiviral strategy. In this study, G-protein coupled receptor (GPCR) and ion channel (IC) host genes in human alveolar epithelial (A549) cells used by influenza virus for replication (Orr-Burks et al., 2021) were examined as miR target genes following A/CA/04/09- or B/Yamagata/16/1988 replication. Thirty-three miRs were predicted to target GPCR or IC genes and their miR mimics were evaluated for their ability to decrease influenza virus replication. Paired miR inhibitors were used as an ancillary measure to confirm or not the antiviral effects of a miR mimic. Fifteen miRs lowered influenza virus replication and four miRs were found to reduce replication irrespective of virus strain and type differences. These findings provide evidence for novel miR disease intervention strategies for influenza viruses.