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Sarah Dahlberg,1 Ellen T Chang,1 Sheila R Weiss,1 Pamela Dopart,1 Errol Gould,2 Mary E Ritchey3 1Exponent, Inc, Menlo Park, CA, 94025, USA; 2Currax Pharmaceuticals LLC., Brentwood, TN, 37027, USA; 3Med Tech Epi, LLC., Philadelphia, PA, 19147, USACorrespondence: Errol Gould, Currax Pharmaceuticals LLC, 155 Franklin Road, Suite 450, Brentwood, TN, 37027, USA, Email egould@curraxpharma.comAbstract: Naltrexone/Bupropion extended release (ER; Contrave) is an extended-release, fixed-dose combination medication of naltrexone (8 mg) and bupropion (90 mg) for patients with obesity or overweight with at least one weight-related comorbidity. Obese and overweight patients with or without comorbidities are at increased cardiovascular (CV) risk. Due to the increased CV risk profile in this patient population, this systematic literature review was conducted to assess human studies reporting major adverse CV events (MACE) and other CV events. A priori eligibility criteria included clinical studies (randomized and observational) published from January 1, 2012, to September 30, 2021, with data comparing users of naltrexone/bupropion ER, naltrexone with bupropion, bupropion without naltrexone, or naltrexone without bupropion versus comparator groups (placebo or other treatments), and with sufficient information to determine the frequency of MACE or other CV adverse events by treatment group. Among 2539 English-language articles identified, 70 articles met the eligibility criteria: seven studies of naltrexone/bupropion ER or naltrexone with bupropion, 32 studies of bupropion, and 31 studies of naltrexone. No studies reported an increased risk of MACE among users of naltrexone/bupropion ER, naltrexone with bupropion, or bupropion or naltrexone individually compared with nonusers. One-half of the available studies (n = 35) reported no (zero) CV events and the other half (n = 35) reported that a non-zero frequency of CV events occurred. Four studies reported data on MACE, including three studies of bupropion and one study of naltrexone/bupropion ER. For composite MACE and its components, the difference in proportions between naltrexone/bupropion ER-, bupropion-, or naltrexone-treated patients compared with active comparators or placebo-treated patients did not exceed 2.5%. In conclusion, the available human evidence does not indicate an increased risk of CV events or MACE following use of naltrexone/bupropion ER, naltrexone with bupropion, or the individual components.Keywords: MACE, obese, overweight, cardiovascular risk

The spike (S) glycoprotein of mouse hepatitis virus (MHV) is a major determinant of neurovirulence. Using targeted recombination we previously demonstrated that the S gene of the highly neurovirulent MHV-4 conferred a dramatic increase in neurovirulence to the mildly neurovirulent MHV-A59. To identify the genetic determinants of neurovirulence within the MHV-4 spike, we generated isogenic recombinant viruses containing various MHV-4/MHV-A59 chimeric spike genes, and studied their phenotypes in vivo. The MHV-4/MHV-A59 chimeric spike genes consisted of either reciprocal exchanges between the S1 and S2 spike subunits, or smaller exchanges specifically in the hypervariable region (HVR) of S1. The chimeric spike gene containing recombinants all exhibited efficient replication in vitro, yet many were severely attenuated for virulence in vivo. Furthermore, these attenuated recombinants exhibited decreased titers of infectious virus in the brain relative to the parental recombinant viruses containing the full-length MHV-4 or MHV-A59 spike genes. This is the first report that compares the neurovirulence and pathogenesis of isogenic viruses with defined alterations in the MHV spike protein. From these studies, it appears that the interactions of multiple regions of the MHV spike, including the HVR, act in concert to allow for efficient infection of and virulence in the murine central nervous system.

Background: Combination therapy with alendronate and estrogen for 2 years increases bone mineral density at the spine and hip more than does therapy with either agent alone. Changes in bone mineral density after discontinuation of therapy have not been compared directly.Objective: To determine the rate of bone loss when therapy with alendronate, estrogen, or both agents is discontinued.Design: Double-blind, placebo-controlled discontinuation trial.Setting: 18 U.S. centers.Patients: 244 postmenopausal, hysterectomized women 44 to 77 years of age.Intervention: 2 years of therapy with alendronate, 10 mg/d (n = 92); conjugated estrogen, 0.625 mg/d (n = 143); alendronate and conjugated estrogen (n = 140); or placebo (n = 50). At year 3, women were allocated into five groups: Twenty-eight women continued to take placebo and 44 women continued to take combination therapy, but 50 women taking alendronate, 81 taking conjugated estrogen, and 41 taking combination therapy were switched to placebo.Measurements: Bone mineral density and biochemical markers of bone turnover.Results: Women taking alendronate or combination therapy who were switched to placebo for year 3 of the study maintained bone mass. Bone mineral density in these women was 4.1% (CI, 2.6% to 5.7%) and 6.6% (CI, 5.0% to 8.2%) higher, respectively, at the spine (P < 0.001 for both treatment comparisons) and 3.5% (CI, 2.3% to 4.6%) and 3.0% (CI, 1.8% to 4.2%) higher, respectively, at the trochanter (P < 0.001 for both treatment comparisons) than that in women previously taking estrogen who were switched to placebo. In contrast, women who were taking estrogen and were switched to placebo during year 3 experienced a 4.5% decrease at the spine (95% CI, -5.0% to -4.0%) and a 2.4% decrease at the trochanter (CI, -2.7% to -2.1%) (P < 0.001 for both changes). Compared with women who took placebo for 3 years, women who took estrogen for 2 years and were then switched to placebo had a bone mineral density that was 2.9% higher (CI, 1.2% to 4.6%) at the spine (P < 0.05) and 2.9% higher (CI, 1.6% to 4.2%) at the trochanter (P < 0.001). Changes in biochemical markers during year 3 did not differ among the groups that discontinued active treatment.Conclusions: Accelerated bone loss is seen after withdrawal of estrogen therapy but not after withdrawal of alendronate or combination therapy. The differential effects after withdrawal of therapy should be considered in the management of postmenopausal osteoporosis. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To characterize risks to infants and young children from drugs and biological products that were identified in spontaneous adverse event reports submitted to the US Food and Drug Administration. METHODS: Of >500 000 MedWatch adverse event reports received by the Food and Drug Administration from November 1997 through December 2000, we identified 7111 reports about infants and children younger than age 2. The reports were analyzed for health outcome (eg, death, hospitalization, congenital anomaly), principal suspect drug, and whether the route of drug exposure was direct administration or through the mother in the perinatal period. RESULTS: Drug therapy was associated with an average of 243 reported deaths annually over the 38-month study period, with 100 (41%) occurring during the first month of life and 204 (84%) during the first year. In 1432 (24%) reported adverse event cases of all levels of severity, exposure to the drug was from the mother during pregnancy, delivery, or lactation. Although 1902 different drugs, biological products, and other chemicals were identified in the reports, only 17 drugs or biological products were a suspect in 54% of all serious and fatal adverse events in drugs administered directly. CONCLUSION: Adverse reactions to drug therapy are a significant cause of death and injury in infants and children under 2 years of age. Drugs administered to the mother in the perinatal period constituted a major route of exposure to adverse drug advents. These results underscore the need for additional drug testing in the youngest pediatric patients and for carefully weighing the risks versus benefits of medication. [Abstract for this article also available on page 997 of printed version. Full article available at http://www.pediatrics.org/cgi/content/full/110/5/e53] [ABSTRACT FROM AUTHOR]

Ezetimibe is a lipid-lowering drug that inhibits the intestinal absorption of dietary and biliary cholesterol by blocking passage across the intestinal wall. The efficacy and safety of adding ezetimibe to ongoing statin therapy in patients with primary hypercholesterolemia was evaluated in a randomized, double-blind, placebo-controlled study. The study group included 769 adults (aged > or =18 years) with primary hypercholesterolemia who had not achieved National Cholesterol Education Program (NCEP) Adult Treatment Panel II goals with dietary alteration and statin monotherapy. Patients receiving a stable dose of a statin for > or =6 weeks were randomized to receive concurrent treatment with placebo (n = 390) or ezetimibe (n = 379), 10 mg/day, in addition to continuing their open-label statin for 8 weeks. The primary efficacy variable was the percent change in low-density lipoprotein (LDL) cholesterol from baseline with statin monotherapy to end point after intervention (secondary variables: high-density lipoprotein [HDL] cholesterol and triglycerides). Ongoing statin therapy plus ezetimibe led to changes of -25.1% for LDL cholesterol (HDL cholesterol +2.7%; triglycerides -14.0%) compared with LDL cholesterol -3.7% (p <0.001), HDL cholesterol +1.0% (p <0.05), and triglycerides -2.9% (p <0.001) for placebo added to ongoing statin therapy. Among patients not at LDL cholesterol goal at on-statin baseline, 71.5% receiving statin plus ezetimibe versus 18.9% receiving statin plus placebo reached goal at end point (odds ratio 23.7; p <0.001). The co-administration of statin and ezetimibe was generally well tolerated. Adding ezetimibe to ongoing statin therapy led to substantial additional reduction in LDL cholesterol levels, facilitating attainment of NCEP goals. Ezetimibe offers a new therapeutic option for patients receiving statins who require further reduction in LDL cholesterol. [ABSTRACT FROM AUTHOR]

This randomized, multicenter, double-blind parallel-group study was performed to evaluate the lipid-altering efficacy and safety of simvastatin 80 mg/day, a dose twice the current maximum recommended dose. At 20 centers in the United States, 521 male and female hypercholesterolemic patients were randomly assigned in a ratio of 2:3 to receive simvastatin 40 or 80 mg once daily, respectively, for 24 weeks in conjunction with a lipid-lowering diet. Patients met National Cholesterol Education Program (NCEP) low-density lipoprotein (LDL) cholesterol criteria for pharmacologic treatment. The mean percentage reductions (95% confidence intervals) from baseline in LDL cholesterol averaged at weeks 18 and 24 were 38% (-40 to -36) and 46% (-47 to -45) for the 40- and 80-mg groups, respectively (p <0.001 between groups). One third of patients on the 40- and 80-mg doses achieved an LDL cholesterol reduction of 46% and > or = 53%, respectively. Decreases in apolipoprotein B, total cholesterol, and triglycerides were also significantly greater among patients receiving 80 mg/day. Simvastatin was well tolerated in both groups. Two patients (0.6%) in the 80-mg group developed myopathy. Consecutive, clinically significant hepatic transaminase elevations occurred in 3 (1.0%) and 6 (1.9%) patients in the 40- and 80-mg groups, respectively (p= 0.486). In conclusion, simvastatin 80 mg/day provided substantial reductions in LDL cholesterol, allowing most patients to reach their NCEP target levels; it also had an excellent safety and tolerability profile. [ABSTRACT FROM AUTHOR]

Background: Viral infections have long been implicated in the development of chronic rhinosinusitis with nasal polyps (CRSwNP). Given widespread exposure to the common cold coronavirus 229E (HCoV229E), we sought to investigate how HCoV-229E is cleared and stimulates interferon pathways in air-liquid interface (ALI) cultures from patients with CRSwNP., Objective: The objective of this study was to identify whether viral clearance and ISG expression is different in ALI cultures from donors with CRSwNP compared with controls., Methods: Plaque assays were used to quantify infectious virus released by infected air-liquid interface (ALI) cultures derived from patients with CRSwNP compared to patients without CRS (controls). Additionally, mock and induced levels of Interferon Stimulated Genes (ISGs) mRNA following HCoV-229E infection were quantified by RT-qPCR., Results: Quantification of infectious virus by plaque assay reveals that CRSwNP ALI cultures were equally susceptible to HCoV-229E infection, and surprisingly viral titers dropped significantly faster than in the control ALI cultures. We further demonstrate that this accelerated viral clearance correlates with increased mRNA expression of at least 4 ISGs following viral infection in the CRSwNP ALIs compared to the control ALIs., Conclusion: This study paradoxically demonstrates that ALI cultures from patients with CRSwNP are more efficient at clearing the common cold HCoV-229E virus compared to controls. We also demonstrate significantly increased ISG mRNA expression following HCoV-229E infection in CRSwNP. These findings call for further investigation into the effect of unimpaired interferon signaling on the type 2 inflammatory environment in patients with CRSwNP., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The betacoronavirus genus contains five of the seven human viruses, making it a particularly critical area of research to prepare for future viral emergence. We utilized three human betacoronaviruses, one from each subgenus- HCoV-OC43 (embecovirus), SARS-CoV-2 (sarbecovirus) and MERS-CoV (merbecovirus)- to study betacoronavirus interaction with the PKR-like ER kinase (PERK) pathway of the integrated stress response (ISR)/unfolded protein response (UPR). The PERK pathway becomes activated by an abundance of unfolded proteins within the endoplasmic reticulum (ER), leading to phosphorylation of eIF2α and translational attenuation in lung derived cell lines. We demonstrate that MERS-CoV, HCoV-OC43, and SARS-CoV-2 all activate PERK and induce responses downstream of p-eIF2α, while only SARS-CoV-2 induces detectable p-eIF2α during infection. Using a small molecule inhibitor of eIF2α dephosphorylation, we provide evidence that MERS-CoV and HCoV-OC43 maximize replication through p-eIF2α dephosphorylation. Interestingly, genetic ablation of GADD34 expression, an inducible phosphatase 1 (PP1)-interacting partner targeting eIF2α for dephosphorylation, did not significantly alter HCoV-OC43 or SARS-CoV-2 replication, while siRNA knockdown of the constitutive PP1 partner, CReP, dramatically reduced HCoV-OC43 replication. Combining growth arrest and DNA damage-inducible protein (GADD34) knockout with peripheral ER membrane-targeted protein (CReP) knockdown had the maximum impact on HCoV-OC43 replication, while SARS-CoV-2 replication was unaffected. Overall, we conclude that eIF2α dephosphorylation is critical for efficient protein production and replication during MERS-CoV and HCoV-OC43 infection. SARS-CoV-2, however, appears to be insensitive to p-eIF2α and, during infection, may even downregulate dephosphorylation to limit host translation., Importance: Lethal human betacoronaviruses have emerged three times in the last two decades, causing two epidemics and a pandemic. Here, we demonstrate differences in how these viruses interact with cellular translational control mechanisms. Utilizing inhibitory compounds and genetic ablation, we demonstrate that MERS-CoV and HCoV-OC43 benefit from keeping p-eIF2α levels low to maintain high rates of virus translation while SARS-CoV-2 tolerates high levels of p-eIF2α. We utilized a PP1:GADD34/CReP inhibitor, GADD34 KO cells, and CReP-targeting siRNA to investigate the therapeutic potential of these pathways. While ineffective for SARS-CoV-2, we found that HCoV-OC43 seems to primarily utilize CReP to limit p-eIF2a accumulation. This work highlights the need to consider differences amongst these viruses, which may inform the development of host-directed pan-coronavirus therapeutics.

COVID-19 syndrome is characterized by acute lung injury, hypoxemic respiratory failure, and high mortality. Alveolar type 2 (AT2) cells are essential for gas exchange, repair, and regeneration of distal lung epithelium. We have shown that the causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and other members of the β-coronavirus genus induce an endoplasmic reticulum (ER) stress response in vitro; however, the consequences for host AT2 cell function in vivo are less understood. To study this, two murine models of coronavirus infection were used-mouse hepatitis virus-1 (MHV-1) in A/J mice and a mouse-adapted SARS-CoV-2 strain. MHV-1-infected mice exhibited dose-dependent weight loss with histological evidence of distal lung injury accompanied by elevated bronchoalveolar lavage fluid (BALF) cell counts and total protein. AT2 cells showed evidence of both viral infection and increased BIP/GRP78 expression, consistent with activation of the unfolded protein response (UPR). The AT2 UPR included increased inositol-requiring enzyme 1α (IRE1α) signaling and a biphasic response in PKR-like ER kinase (PERK) signaling accompanied by marked reductions in AT2 and BALF surfactant protein (SP-B and SP-C) content, increases in surfactant surface tension, and emergence of a reprogrammed epithelial cell population ( Krt8 + and Cldn4 + ). The loss of a homeostatic AT2 cell state was attenuated by treatment with the IRE1α inhibitor OPK-711. As a proof-of-concept, C57BL6 mice infected with mouse-adapted SARS-CoV-2 demonstrated similar lung injury and evidence of disrupted surfactant homeostasis. We conclude that lung injury from β-coronavirus infection results from an aberrant host response, activating multiple AT2 UPR stress pathways, altering surfactant metabolism/function, and changing AT2 cell state, offering a mechanistic link between SARS-CoV-2 infection, AT2 cell biology, and acute respiratory failure. NEW & NOTEWORTHY COVID-19 syndrome is characterized by hypoxemic respiratory failure and high mortality. In this report, we use two murine models to show that β-coronavirus infection produces acute lung injury, which results from an aberrant host response, activating multiple epithelial endoplasmic reticular stress pathways, disrupting pulmonary surfactant metabolism and function, and forcing emergence of an aberrant epithelial transition state. Our results offer a mechanistic link between SARS-CoV-2 infection, AT2 cell biology, and respiratory failure.

All respiratory viruses establish primary infections in the nasal epithelium, where efficient innate immune induction may prevent dissemination to the lower airway and thus minimize pathogenesis. Human coronaviruses (HCoVs) cause a range of pathologies, but the host and viral determinants of disease during common cold versus lethal HCoV infections are poorly understood. We model the initial site of infection using primary nasal epithelial cells cultured at an air-liquid interface (ALI). HCoV-229E, HCoV-NL63, and human rhinovirus-16 are common cold-associated viruses that exhibit unique features in this model: early induction of antiviral interferon (IFN) signaling, IFN-mediated viral clearance, and preferential replication at nasal airway temperature (33 °C) which confers muted host IFN responses. In contrast, lethal SARS-CoV-2 and MERS-CoV encode antagonist proteins that prevent IFN-mediated clearance in nasal cultures. Our study identifies features shared among common cold-associated viruses, highlighting nasal innate immune responses as predictive of infection outcomes and nasally directed IFNs as potential therapeutics., Competing Interests: Competing interests statement:S.R.W. consults for Powell Gilbert LLP. N.A.C. consults for GSK, AstraZeneca, Novartis, and Sanofi/Regeneron; and has a licensing agreement with GeneOne Life Sciences. N.A.C. has US Patent “Therapy and Diagnostics for Respiratory Infection” (10,881,698 B2, WO20913112865). S.R.W. has had an editorial/comment co-publication with the reviewers A.P. and J.U.J., within the last 4 y.

The SARS-CoV-2 pandemic was marked with emerging viral variants, some of which were designated as variants of concern (VOCs) due to selection and rapid circulation in the human population. Here, we elucidate functional features of each VOC linked to variations in replication rate. Patient-derived primary nasal cultures grown at air-liquid interface were used to model upper respiratory infection and compared to cell lines derived from human lung epithelia. All VOCs replicated to higher titers than the ancestral virus, suggesting a selection for replication efficiency. In primary nasal cultures, Omicron replicated to the highest titers at early time points, followed by Delta, paralleling comparative studies of population sampling. All SARS-CoV-2 viruses entered the cell primarily via a transmembrane serine protease 2 (TMPRSS2)-dependent pathway, and Omicron was more likely to use an endosomal route of entry. All VOCs activated and overcame dsRNA-induced cellular responses, including interferon (IFN) signaling, oligoadenylate ribonuclease L degradation, and protein kinase R activation. Among the VOCs, Omicron infection induced expression of the most IFN and IFN-stimulated genes. Infections in nasal cultures resulted in cellular damage, including a compromise of cell barrier integrity and loss of nasal cilia and ciliary beating function, especially during Delta infection. Overall, Omicron was optimized for replication in the upper respiratory tract and least favorable in the lower respiratory cell line, and Delta was the most cytopathic for both upper and lower respiratory cells. Our findings highlight the functional differences among VOCs at the cellular level and imply distinct mechanisms of pathogenesis in infected individuals., Importance: Comparative analysis of infections by SARS-CoV-2 ancestral virus and variants of concern, including Alpha, Beta, Delta, and Omicron, indicated that variants were selected for efficiency in replication. In infections of patient-derived primary nasal cultures grown at air-liquid interface to model upper respiratory infection, Omicron reached the highest titers at early time points, a finding that was confirmed by parallel population sampling studies. While all infections overcame dsRNA-mediated host responses, infections with Omicron induced the strongest interferon and interferon-stimulated gene response. In both primary nasal cultures and lower respiratory cell line, infections by Delta were most damaging to the cells as indicated by syncytia formation, loss of cell barrier integrity, and nasal ciliary function., Competing Interests: The authors declare no conflict of interest.

Severe acute respiratory syndrome coronavirus (SARS-CoV)-2 has caused millions of deaths since its emergence in 2019. Innate immune antagonism by lethal CoVs such as SARS-CoV-2 is crucial for optimal replication and pathogenesis. The conserved nonstructural protein 15 (nsp15) endoribonuclease (EndoU) limits activation of double-stranded (ds)RNA-induced pathways, including interferon (IFN) signaling, protein kinase R (PKR), and oligoadenylate synthetase/ribonuclease L (OAS/RNase L) during diverse CoV infections including murine coronavirus and Middle East respiratory syndrome (MERS)-CoV. To determine how nsp15 functions during SARS-CoV-2 infection, we constructed a recombinant SARS-CoV-2 (nsp15 mut ) expressing catalytically inactivated nsp15, which we show promoted increased dsRNA accumulation. Infection with SARS-CoV-2 nsp15 mut led to increased activation of the IFN signaling and PKR pathways in lung-derived epithelial cell lines and primary nasal epithelial air-liquid interface (ALI) cultures as well as significant attenuation of replication in ALI cultures compared to wild-type virus. This replication defect was rescued when IFN signaling was inhibited with the Janus activated kinase (JAK) inhibitor ruxolitinib. Finally, to assess nsp15 function in the context of minimal (MERS-CoV) or moderate (SARS-CoV-2) innate immune induction, we compared infections with SARS-CoV-2 nsp15 mut and previously described MERS-CoV nsp15 mutants. Inactivation of nsp15 had a more dramatic impact on MERS-CoV replication than SARS-CoV-2 in both Calu3 cells and nasal ALI cultures suggesting that SARS-CoV-2 can better tolerate innate immune responses. Taken together, SARS-CoV-2 nsp15 is a potent inhibitor of dsRNA-induced innate immune response and its antagonism of IFN signaling is necessary for optimal viral replication in primary nasal ALI cultures., Competing Interests: Competing interests statement:S.R.W. consults for Powell Gilbert LLP. N.A.C. consults for GSK, AstraZeneca, Novartis, Sanofi/Regeneron. N.A.C. has US Patent “Therapy and Diagnostics for Respiratory Infection” (10,881,698 B2, WO20913112865) and a licensing agreement with GeneOne Life Sciences.

Many viruses, including mammarenaviruses, have evolved mechanisms to counteract different components of the host cell innate immunity, which is required to facilitate robust virus multiplication. The double-stranded RNA (dsRNA) sensor protein kinase receptor (PKR) pathway plays a critical role in the cell anti-viral response. Whether PKR can restrict the multiplication of the Old World mammarenavirus lymphocytic choriomeningitis virus (LCMV) and the mechanisms by which LCMV may counteract the anti-viral functions of PKR have not yet been investigated. Here we present evidence that LCMV infection results in very limited levels of PKR activation, but LCMV multiplication is enhanced in the absence of PKR. In contrast, infection with a recombinant LCMV with a mutation affecting the 3'-5' exonuclease (ExoN) activity of the viral nucleoprotein resulted in robust PKR activation in the absence of detectable levels of dsRNA, which was associated with severely restricted virus multiplication that was alleviated in the absence of PKR. However, pharmacological inhibition of PKR activation resulted in reduced levels of LCMV multiplication. These findings uncovered a complex role of the PKR pathway in LCMV-infected cells involving both pro- and anti-viral activities.IMPORTANCEAs with many other viruses, the prototypic Old World mammarenavirus LCMV can interfere with the host cell innate immune response to infection, which includes the dsRNA sensor PKR pathway. A detailed understanding of LCMV-PKR interactions can provide novel insights about mammarenavirus-host cell interactions and facilitate the development of effective anti-viral strategies against human pathogenic mammarenaviruses. In the present work, we present evidence that LCMV multiplication is enhanced in PKR-deficient cells, but pharmacological inhibition of PKR activation unexpectedly resulted in severely restricted propagation of LCMV. Likewise, we document a robust PKR activation in LCMV-infected cells in the absence of detectable levels of dsRNA. Our findings have revealed a complex role of the PKR pathway during LCMV infection and uncovered the activation of PKR as a druggable target for the development of anti-viral drugs against human pathogenic mammarenaviruses., Competing Interests: The authors declare no conflict of interest.

In the United States (US), biosafety and biosecurity oversight of research on viruses is being reappraised. Safety in virology research is paramount and oversight frameworks should be reviewed periodically. Changes should be made with care, however, to avoid impeding science that is essential for rapidly reducing and responding to pandemic threats as well as addressing more common challenges caused by infectious diseases. Decades of research uniquely positioned the US to be able to respond to the COVID-19 crisis with astounding speed, delivering life-saving vaccines within a year of identifying the virus. We should embolden and empower this strength, which is a vital part of protecting the health, economy, and security of US citizens. Herein, we offer our perspectives on priorities for revised rules governing virology research in the US.

Insectivorous Old World horseshoe bats (Rhinolophus spp.) are the likely source of the ancestral SARS-CoV-2 prior to its spillover into humans and causing the COVID-19 pandemic. Natural coronavirus infections of bats appear to be principally confined to the intestines, suggesting fecal-oral transmission; however, little is known about the biology of SARS-related coronaviruses in bats. Previous experimental challenges of Egyptian fruit bats (Rousettus aegyptiacus) resulted in limited infection restricted to the respiratory tract, whereas insectivorous North American big brown bats (Eptesicus fuscus) showed no evidence of infection. In the present study, we challenged Jamaican fruit bats (Artibeus jamaicensis) with SARS-CoV-2 to determine their susceptibility. Infection was confined to the intestine for only a few days with prominent viral nucleocapsid antigen in epithelial cells, and mononuclear cells of the lamina propria and Peyer's patches, but with no evidence of infection of other tissues; none of the bats showed visible signs of disease or seroconverted. Expression levels of ACE2 were low in the lungs, which may account for the lack of pulmonary infection. Bats were then intranasally inoculated with a replication-defective adenovirus encoding human ACE2 and 5 days later challenged with SARS-CoV-2. Viral antigen was prominent in lungs for up to 14 days, with loss of pulmonary cellularity during this time; however, the bats did not exhibit weight loss or visible signs of disease. From day 7, bats had low to moderate IgG antibody titers to spike protein by ELISA, and one bat on day 10 had low-titer neutralizing antibodies. CD4+ helper T cells became activated upon ex vivo recall stimulation with SARS-CoV-2 nucleocapsid peptide library and exhibited elevated mRNA expression of the regulatory T cell cytokines interleukin-10 and transforming growth factor-β, which may have limited inflammatory pathology. Collectively, these data show that Jamaican fruit bats are poorly susceptible to SARS-CoV-2 but that expression of human ACE2 in their lungs leads to robust infection and an adaptive immune response with low-titer antibodies and a regulatory T cell-like response that may explain the lack of prominent inflammation in the lungs. This model will allow for insight of how SARS-CoV-2 infects bats and how bat innate and adaptive immune responses engage the virus without overt clinical disease., Competing Interests: The JAR laboratory received support from Tonix Pharmaceuticals, Xing Technologies and Zoetis, outside of the reported work. JAR is inventor of patents and patent applications on the use of antivirals and vaccines for the treatment and prevention of virus infections, owned by Kansas State University, KS., (Copyright: © 2023 Burke et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

HCoV-OC43, HCoV-229E, HCoV-NL63, and HCoV-HKU1 are four of the seven known human coronaviruses (HCoVs) and, unlike the highly pathogenic SARS-CoV, MERS-CoV, and SARS-CoV-2, these four so-called seasonal HCoVs generally cause mild upper-respiratory-tract illness. As Biosafety Level 2 (BSL-2) pathogens, the seasonal HCoVs are more accessible and can be used as surrogates for studying the highly pathogenic HCoVs. However, scientists have for many years found these difficult to study because of the lack of a universal culture system and the inability of typical culture methods to yield high-titer infectious stocks. We have developed assays to grow and quantify infectious virus and viral RNA for HCoV-OC43, -229E, and -NL63. We identified which immortalized cell lines should be used to optimize the replication of HCoV-OC43, -229E, and -NL63 in order to generate high titers (Vero E6, Huh-7, and LLC-MK2 cells, respectively). Here we present protocols for improved propagation and quantification of each seasonal HCoV. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Growth of HCoVs Basic Protocol 2: Quantification of HCoV by plaque assay Basic Protocol 3: Quantification of HCoV RNA products of replication Basic Protocol 4: Concentrating HCoVs via ultracentrifugation., (© 2023 Wiley Periodicals LLC.)

Three highly pathogenic human coronaviruses (HCoVs) - SARS-CoV (2002), MERS-CoV (2012), and SARS-CoV-2 (2019) - have emerged and caused significant public health crises in the past 20 years. Four additional HCoVs cause a significant portion of common cold cases each year (HCoV-NL63, -229E, -OC43, and -HKU1), highlighting the importance of studying these viruses in physiologically relevant systems. HCoVs enter the respiratory tract and establish infection in the nasal epithelium, the primary site encountered by all respiratory pathogens. We use a primary nasal epithelial culture system in which patient-derived nasal samples are grown at an air-liquid interface (ALI) to study host-pathogen interactions at this important sentinel site. These cultures recapitulate many features of the in vivo airway, including the cell types present, ciliary function, and mucus production. We describe methods to characterize viral replication, host cell tropism, virus-induced cytotoxicity, and innate immune induction in nasal ALI cultures following HCoV infection, using recent work comparing lethal and seasonal HCoVs as an example 1 . An increased understanding of host-pathogen interactions in the nose has the potential to provide novel targets for antiviral therapeutics against HCoVs and other respiratory viruses that will likely emerge in the future.

The COVID-19 pandemic has escalated the risk of SARS-CoV-2 transmission in the dental practice, especially as droplet-aerosol particles are generated by high-speed instruments. This has heightened awareness of other orally transmitted viruses, including influenza and herpes simplex virus 1 (HSV1), which are capable of threatening life and impairing health. While current disinfection procedures commonly use surface wipe-downs to reduce viral transmission, they are not fully effective. Consequently, this provides the opportunity for a spectrum of emitted viruses to reside airborne for hours and upon surfaces for days. The objective of this study was to develop an experimental platform to identify a safe and effective virucide with the ability to rapidly destroy oral viruses transported within droplets and aerosols. Our test method employed mixing viruses and virucides in a fine-mist bottle atomizer to mimic the generation of oral droplet-aerosols. The results revealed that human betacoronavirus OC43 (related to SARS-CoV-2), human influenza virus (H1N1), and HSV1 from atomizer-produced droplet-aerosols were each fully destroyed by only 100 ppm of hypochlorous acid (HOCl) within 30 s, which was the shortest time point of exposure to the virucide. Importantly, 100 ppm HOCl introduced into the oral cavity is known to be safe for humans. In conclusion, this frontline approach establishes the potential of using 100 ppm HOCl in waterlines to continuously irrigate the oral cavity during dental procedures to expeditiously destroy harmful viruses transmitted within aerosols and droplets to protect practitioners, staff, and other patients.

The nasal epithelium is the initial entry portal and primary barrier to infection by all human coronaviruses (HCoVs). We utilize primary human nasal epithelial cells grown at air-liquid interface, which recapitulate the heterogeneous cellular population as well as mucociliary clearance functions of the in vivo nasal epithelium, to compare lethal [Severe acute respiratory syndrome (SARS)-CoV-2 and Middle East respiratory syndrome-CoV (MERS-CoV)] and seasonal (HCoV-NL63 and HCoV-229E) HCoVs. All four HCoVs replicate productively in nasal cultures, though replication is differentially modulated by temperature. Infections conducted at 33 °C vs. 37 °C (reflective of temperatures in the upper and lower airway, respectively) revealed that replication of both seasonal HCoVs (HCoV-NL63 and -229E) is significantly attenuated at 37 °C. In contrast, SARS-CoV-2 and MERS-CoV replicate at both temperatures, though SARS-CoV-2 replication is enhanced at 33 °C late in infection. These HCoVs also diverge significantly in terms of cytotoxicity induced following infection, as the seasonal HCoVs as well as SARS-CoV-2 cause cellular cytotoxicity as well as epithelial barrier disruption, while MERS-CoV does not. Treatment of nasal cultures with type 2 cytokine IL-13 to mimic asthmatic airways differentially impacts HCoV receptor availability as well as replication. MERS-CoV receptor DPP4 expression increases with IL-13 treatment, whereas ACE2, the receptor used by SARS-CoV-2 and HCoV-NL63, is down-regulated. IL-13 treatment enhances MERS-CoV and HCoV-229E replication but reduces that of SARS-CoV-2 and HCoV-NL63, reflecting the impact of IL-13 on HCoV receptor availability. This study highlights diversity among HCoVs during infection of the nasal epithelium, which is likely to influence downstream infection outcomes such as disease severity and transmissibility.

Multisystem inflammatory syndrome in children (MIS-C) is a rare and severe condition that follows benign COVID-19. We report autosomal recessive deficiencies of OAS1 , OAS2 , or RNASEL in five unrelated children with MIS-C. The cytosolic double-stranded RNA (dsRNA)-sensing OAS1 and OAS2 generate 2'-5'-linked oligoadenylates (2-5A) that activate the single-stranded RNA-degrading ribonuclease L (RNase L). Monocytic cell lines and primary myeloid cells with OAS1, OAS2, or RNase L deficiencies produce excessive amounts of inflammatory cytokines upon dsRNA or severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stimulation. Exogenous 2-5A suppresses cytokine production in OAS1-deficient but not RNase L-deficient cells. Cytokine production in RNase L-deficient cells is impaired by MDA5 or RIG-I deficiency and abolished by mitochondrial antiviral-signaling protein (MAVS) deficiency. Recessive OAS-RNase L deficiencies in these patients unleash the production of SARS-CoV-2-triggered, MAVS-mediated inflammatory cytokines by mononuclear phagocytes, thereby underlying MIS-C.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has killed over 6 million individuals worldwide and continues to spread in countries where vaccines are not yet widely available or its citizens are hesitant to become vaccinated. Therefore, it is critical to unravel the molecular mechanisms that allow SARS-CoV-2 and other coronaviruses to infect and overtake the host machinery of human cells. Coronavirus replication triggers endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR), a key host cell pathway widely believed to be essential for viral replication. We examined the master UPR sensor IRE1α kinase/RNase and its downstream transcription factor effector XBP1s, which is processed through an IRE1α-mediated mRNA splicing event, in human lung-derived cells infected with betacoronaviruses. We found that human respiratory coronavirus OC43 (HCoV-OC43), Middle East respiratory syndrome coronavirus (MERS-CoV), and murine coronavirus (MHV) all induce ER stress and strongly trigger the kinase and RNase activities of IRE1α as well as XBP1 splicing. In contrast, SARS-CoV-2 only partially activates IRE1α through autophosphorylation, but its RNase activity fails to splice XBP1. Moreover, while IRE1α was dispensable for replication in human cells for all coronaviruses tested, it was required for maximal expression of genes associated with several key cellular functions, including the interferon signaling pathway, during SARS-CoV-2 infection. Our data suggest that SARS-CoV-2 actively inhibits the RNase of autophosphorylated IRE1α, perhaps as a strategy to eliminate detection by the host immune system. IMPORTANCE SARS-CoV-2 is the third lethal respiratory coronavirus, after MERS-CoV and SARS-CoV, to emerge this century, causing millions of deaths worldwide. Other common coronaviruses such as HCoV-OC43 cause less severe respiratory disease. Thus, it is imperative to understand the similarities and differences among these viruses in how each interacts with host cells. We focused here on the inositol-requiring enzyme 1α (IRE1α) pathway, part of the host unfolded protein response to virus-induced stress. We found that while MERS-CoV and HCoV-OC43 fully activate the IRE1α kinase and RNase activities, SARS-CoV-2 only partially activates IRE1α, promoting its kinase activity but not RNase activity. Based on IRE1α-dependent gene expression changes during infection, we propose that SARS-CoV-2 prevents IRE1α RNase activation as a strategy to limit detection by the host immune system.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged at the end of 2019 and caused the devastating global pandemic of coronavirus disease 2019 (COVID-19), in part because of its ability to effectively suppress host cell responses 1-3 . In rare cases, viral proteins dampen antiviral responses by mimicking critical regions of human histone proteins 4-8 , particularly those containing post-translational modifications required for transcriptional regulation 9-11 . Recent work has demonstrated that SARS-CoV-2 markedly disrupts host cell epigenetic regulation 12-14 . However, how SARS-CoV-2 controls the host cell epigenome and whether it uses histone mimicry to do so remain unclear. Here we show that the SARS-CoV-2 protein encoded by ORF8 (ORF8) functions as a histone mimic of the ARKS motifs in histone H3 to disrupt host cell epigenetic regulation. ORF8 is associated with chromatin, disrupts regulation of critical histone post-translational modifications and promotes chromatin compaction. Deletion of either the ORF8 gene or the histone mimic site attenuates the ability of SARS-CoV-2 to disrupt host cell chromatin, affects the transcriptional response to infection and attenuates viral genome copy number. These findings demonstrate a new function of ORF8 and a mechanism through which SARS-CoV-2 disrupts host cell epigenetic regulation. Further, this work provides a molecular basis for the finding that SARS-CoV-2 lacking ORF8 is associated with decreased severity of COVID-19., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

La Crosse virus (LACV) is a major cause of pediatric encephalitis and aseptic meningitis in the Midwestern, Mid-Atlantic, and Southern United States, where it is an emerging pathogen. The LACV Gc glycoprotein plays a critical role in the neuropathogenesis of LACV encephalitis as the putative virus attachment protein. Previously, we identified and experimentally confirmed the location of the LACV fusion peptide within Gc and generated a panel of recombinant LACVs (rLACVs) containing mutations in the fusion peptide as well as the wild-type sequence. These rLACVs retained their ability to cause neuronal death in a primary embryonic rat neuronal culture system, despite decreased replication and fusion phenotypes. To test the role of the fusion peptide in vivo, we tested rLACVs in an age-dependent murine model of LACV encephalitis. When inoculated directly into the CNS of young adult mice (P28), the rLACV fusion peptide mutants were as neurovirulent as the rLACV engineered with a wild-type sequence, confirming the results obtained in tissue culture. In contrast, the fusion peptide mutant rLACVs were less neuroinvasive when suckling (P3) or weanling (P21) mice were inoculated peripherally, demonstrating that the LACV fusion peptide is a determinant of neuroinvasion, but not of neurovirulence. In a challenge experiment, we found that peripheral challenge of weanling (P21) mice with fusion peptide mutant rLACVs protected from a subsequent WT-LACV challenge, suggesting that mutations in the fusion peptide are an attractive target for generating live-attenuated virus vaccines. Importantly, the high degree of conservation of the fusion peptide amongst the Bunyavirales and, structurally, other arboviruses suggests that these findings are broadly applicable to viruses that use a class II fusion mechanism and cause neurologic disease.

Middle East respiratory syndrome coronavirus (MERS-CoV) emerged into humans in 2012, causing highly lethal respiratory disease. The severity of disease may be, in part, because MERS-CoV is adept at antagonizing early innate immune pathways—interferon (IFN) production and signaling, protein kinase R (PKR), and oligoadenylate synthetase/ribonuclease L (OAS/RNase L)—activated in response to viral double-stranded RNA (dsRNA) generated during genome replication. This is in contrast to severe acute respiratory syndrome CoV-2 (SARS-CoV-2), which we recently reported to activate PKR and RNase L and, to some extent, IFN signaling. We previously found that MERS-CoV accessory proteins NS4a (dsRNA binding protein) and NS4b (phosphodiesterase) could weakly suppress these pathways, but ablation of each had minimal effect on virus replication. Here we investigated the antagonist effects of the conserved coronavirus endoribonuclease (EndoU), in combination with NS4a or NS4b. Inactivation of EndoU catalytic activity alone in a recombinant MERS-CoV caused little if any effect on activation of the innate immune pathways during infection. However, infection with recombinant viruses containing combined mutations with inactivation of EndoU and deletion of NS4a or inactivation of the NS4b phosphodiesterase promoted robust activation of dsRNA-induced innate immune pathways. This resulted in at least tenfold attenuation of replication in human lung–derived A549 and primary nasal cells. Furthermore, replication of these recombinant viruses could be rescued to the level of wild-type MERS-CoV by knockout of host immune mediators MAVS, PKR, or RNase L. Thus, EndoU and accessory proteins NS4a and NS4b together suppress dsRNA-induced innate immunity during MERS-CoV infection in order to optimize viral replication.

Eukaryotic cells recognize intracellular pathogens through pattern recognition receptors, including sensors of aberrant nucleic acid structures. Sensors of double-stranded RNA (dsRNA) are known to detect replication intermediates of RNA viruses. It has long been suggested that annealing of mRNA from symmetrical transcription of both top and bottom strands of DNA virus genomes can produce dsRNA during infection. Supporting this hypothesis, nearly all DNA viruses encode inhibitors of dsRNA-recognition pathways. However, direct evidence that DNA viruses produce dsRNA is lacking. Contrary to dogma, we show that the nuclear-replicating DNA virus adenovirus (AdV) does not produce detectable levels of dsRNA during infection. In contrast, abundant dsRNA is detected within the nucleus of cells infected with AdV mutants defective for viral RNA processing. In the presence of nuclear dsRNA, the cytoplasmic dsRNA sensor PKR is relocalized and activated within the nucleus. Accumulation of viral dsRNA occurs in the late phase of infection, when unspliced viral transcripts form intron/exon base pairs between top and bottom strand transcripts. We propose that DNA viruses actively limit dsRNA formation by promoting efficient splicing and mRNA processing, thus avoiding detection and restriction by host innate immune sensors of pathogenic nucleic acids., (© The Author(s) 2021. Published by Oxford University Press on behalf of Nucleic Acids Research.)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections have spilled over from humans to companion and wild animals since the inception of the global COVID-19 pandemic. However, whole genome sequencing data of the viral genomes that infect non-human animal species have been scant. Here, we detected and sequenced a SARS-CoV-2 delta variant (AY.3) in fecal samples from an 11-year-old domestic house cat previously exposed to an owner who tested positive for SARS-CoV-2. Molecular testing of two fecal samples collected 7 days apart yielded relatively high levels of viral RNA. Sequencing of the feline-derived viral genomes showed the two to be identical, and differing by between 4 and 14 single nucleotide polymorphisms in pairwise comparisons to human-derived lineage AY.3 sequences collected in the same geographic area and time period. However, several mutations unique to the feline samples reveal their divergence from this cohort on phylogenetic analysis. These results demonstrate continued spillover infections of emerging SARS-CoV-2 variants that threaten human and animal health, as well as highlight the importance of collecting fecal samples when testing for SARS-CoV-2 in animals. To the authors' knowledge, this is the first published case of a SARS-CoV-2 delta variant in a domestic cat in the United States.

Background: High-sensitivity severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen assays are desirable to mitigate false negative results. Limited data are available to quantify and track SARS-CoV-2 antigen burden in respiratory samples from different populations., Methods: We developed the Microbubbling SARS-CoV-2 Antigen Assay (MSAA) with smartphone readout, with a limit of detection of 0.5 pg/mL (10.6 fmol/L) nucleocapsid antigen or 4000 copies/mL inactivated SARS-CoV-2 virus in nasopharyngeal (NP) swabs. We developed a computer vision and machine learning-based automatic microbubble image classifier to accurately identify positives and negatives and quantified and tracked antigen dynamics in intensive care unit coronavirus disease 2019 (COVID-19) inpatients and immunocompromised COVID-19 patients., Results: Compared to qualitative reverse transcription-polymerase chain reaction methods, the MSAA demonstrated a positive percentage agreement of 97% (95% CI 92%-99%) and a negative percentage agreement of 97% (95% CI 94%-100%) in a clinical validation study with 372 residual clinical NP swabs. In immunocompetent individuals, the antigen positivity rate in swabs decreased as days-after-symptom-onset increased, despite persistent nucleic acid positivity. Antigen was detected for longer and variable periods of time in immunocompromised patients with hematologic malignancies. Total microbubble volume, a quantitative marker of antigen burden, correlated inversely with cycle threshold values and days-after-symptom-onset. Viral sequence variations were detected in patients with long duration of high antigen burden., Conclusions: The MSAA enables sensitive and specific detection of acute infections and quantification and tracking of antigen burden and may serve as a screening method in longitudinal studies to identify patients who are likely experiencing active rounds of ongoing replication and warrant close viral sequence monitoring., (© American Association for Clinical Chemistry 2021. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Purpose: To compare risks of interstitial lung disease (ILD) between patients treated with dronedarone versus other antiarrhythmics., Methods: Parallel retrospective cohort studies were conducted in the United States Department of Defense Military Health System database (DoD) and the HealthCore Integrated Research Database (HIRD). Study patients were treated for atrial fibrillation (AF) with dronedarone, amiodarone, sotalol, or flecainide. Propensity score matching was employed to create analysis cohorts balanced on baseline variables considered potential confounders of treatment decisions. The study period of July 20, 2008 through September 30, 2014 included a 1-year baseline and minimum 6 months of follow-up, for patients with drugs dispensed between July 20, 2009 and March 31, 2014. Suspect ILD outcomes were reviewed by independent adjudicators. Cox proportional hazards regression compared risk of confirmed ILD between dronedarone and each comparator cohort. A sensitivity analysis examined the effect of broadening the outcome definition., Results: A total 72 ILD cases (52 DoD; 20 HIRD) were confirmed among 27 892 patients. ILD risk was significantly higher among amiodarone than dronedarone initiators in DoD (HR = 2.5; 95% CI = 1.1-5.3, p = 0.02). No difference was detected in HIRD (HR = 1.0; 95% CI = 0.4-2.4). Corresponding risks in sotalol and flecainide exposure groups did not differ significantly from dronedarone in either database., Conclusions: ILD risk among AF patients initiated on dronedarone therapy was comparable to or lower than that of amiodarone initiators, and similar to that of new sotalol or flecainide users. This finding suggests that elevated ILD risk associated with amiodarone does not necessarily extend to dronedarone or other antiarrhythmic drugs., (© 2021 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.)