Publications by authors named "Kevin S Harrod"

58 Publications

Water-soluble tocopherol derivatives inhibit SARS-CoV-2 RNA-dependent RNA polymerase.

bioRxiv 2021 Jul 14. Epub 2021 Jul 14.

The recent emergence of a novel coronavirus, SARS-CoV-2, has led to the global pandemic of the severe disease COVID-19 in humans. While efforts to quickly identify effective antiviral therapies have focused largely on repurposing existing drugs , the current standard of care, remdesivir, remains the only authorized antiviral intervention of COVID-19 and provides only modest clinical benefits . Here we show that water-soluble derivatives of α-tocopherol have potent antiviral activity and synergize with remdesivir as inhibitors of the SARS-CoV-2 RNA-dependent RNA polymerase (RdRp). Through an artificial-intelligence-driven screen and viral inhibition assay, we identified D-α-tocopherol polyethylene glycol succinate (TPGS) as an effective antiviral against SARS-CoV-2 and β-coronaviruses more broadly that also displays strong synergy with remdesivir. We subsequently determined that TPGS and other water-soluble derivatives of α-tocopherol inhibit the transcriptional activity of purified SARS-CoV-2 RdRp and identified affinity binding sites for these compounds within a conserved, hydrophobic interface between SARS-CoV-2 nonstructural protein 7 and nonstructural protein 8 that is functionally implicated in the assembly of the SARS-CoV-2 RdRp . In summary, we conclude that solubilizing modifications to α-tocopherol allow it to interact with the SARS-CoV-2 RdRp, making it an effective antiviral molecule alone and even more so in combination with remdesivir. These findings are significant given that many tocopherol derivatives, including TPGS, are considered safe for humans, orally bioavailable, and dramatically enhance the activity of the only approved antiviral for SARS-CoV-2 infection .
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http://dx.doi.org/10.1101/2021.07.13.449251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8288149PMC
July 2021

A metabolomic endotype of bioenergetic dysfunction predicts mortality in critically ill patients with acute respiratory failure.

Sci Rep 2021 May 18;11(1):10515. Epub 2021 May 18.

Wake Forest Baptist Medical Center, Winston-Salem, NC, USA.

Acute respiratory failure (ARF) requiring mechanical ventilation, a complicating factor in sepsis and other disorders, is associated with high morbidity and mortality. Despite its severity and prevalence, treatment options are limited. In light of accumulating evidence that mitochondrial abnormalities are common in ARF, here we applied broad spectrum quantitative and semiquantitative metabolomic analyses of serum from ARF patients to detect bioenergetic dysfunction and determine its association with survival. Plasma samples from surviving and non-surviving patients (N = 15/group) were taken at day 1 and day 3 after admission to the medical intensive care unit and, in survivors, at hospital discharge. Significant differences between survivors and non-survivors (ANOVA, 5% FDR) include bioenergetically relevant intermediates of redox cofactors nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP), increased acyl-carnitines, bile acids, and decreased acyl-glycerophosphocholines. Many metabolites associated with poor outcomes are substrates of NAD(P)-dependent enzymatic processes, while alterations in NAD cofactors rely on bioavailability of dietary B-vitamins thiamine, riboflavin and pyridoxine. Changes in the efficiency of the nicotinamide-derived cofactors' biosynthetic pathways also associate with alterations in glutathione-dependent drug metabolism characterized by substantial differences observed in the acetaminophen metabolome. Based on these findings, a four-feature model developed with semi-quantitative and quantitative metabolomic results predicted patient outcomes with high accuracy (AUROC = 0.91). Collectively, this metabolomic endotype points to a close association between mitochondrial and bioenergetic dysfunction and mortality in human ARF, thus pointing to new pharmacologic targets to reduce mortality in this condition.
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http://dx.doi.org/10.1038/s41598-021-89716-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8131588PMC
May 2021

Influenza Antiviral Subversion: Now the Host Is in on the Act.

Am J Respir Cell Mol Biol 2021 Jul;65(1):1-3

Department of Anesthesiology and Perioperative Medicine University of Alabama at Birmingham Birmingham, Alabama.

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http://dx.doi.org/10.1165/rcmb.2021-0094EDDOI Listing
July 2021

Single-dose intranasal administration of AdCOVID elicits systemic and mucosal immunity against SARS-CoV-2 in mice.

bioRxiv 2020 Oct 11. Epub 2020 Oct 11.

The coronavirus disease 2019 (COVID-19) pandemic has highlighted the urgent need for effective preventive vaccination to reduce burden and spread of severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) in humans. Intranasal vaccination is an attractive strategy to prevent COVID-19 as the nasal mucosa represents the first-line barrier to SARS-CoV-2 entry before viral spread to the lung. Although SARS-CoV-2 vaccine development is rapidly progressing, the current intramuscular vaccines are designed to elicit systemic immunity without conferring mucosal immunity. Here, we show that AdCOVID, an intranasal adenovirus type 5 (Ad5)-vectored vaccine encoding the receptor binding domain (RBD) of the SARS-CoV-2 spike protein, elicits a strong and focused immune response against RBD through the induction of mucosal IgA, serum neutralizing antibodies and CD4+ and CD8+ T cells with a Th1-like cytokine expression profile. Therefore, AdCOVID, which promotes concomitant systemic and local mucosal immunity, represents a promising COVID-19 vaccine candidate.
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http://dx.doi.org/10.1101/2020.10.10.331348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7553185PMC
October 2020

Influenza-Induced Oxidative Stress Sensitizes Lung Cells to Bacterial-Toxin-Mediated Necroptosis.

Cell Rep 2020 08;32(8):108062

Department of Microbiology, The University of Alabama at Birmingham, Birmingham, AL 35294-2170, USA.

Pneumonias caused by influenza A virus (IAV) co- and secondary bacterial infections are characterized by their severity and high mortality rate. Previously, we have shown that bacterial pore-forming toxin (PFT)-mediated necroptosis is a key driver of acute lung injury during bacterial pneumonia. Here, we evaluate the impact of IAV on PFT-induced acute lung injury during co- and secondary Streptococcus pneumoniae (Spn) infection. We observe that IAV synergistically sensitizes lung epithelial cells for PFT-mediated necroptosis in vitro and in murine models of Spn co-infection and secondary infection. Pharmacoelogical induction of oxidative stress without virus sensitizes cells for PFT-mediated necroptosis. Antioxidant treatment or inhibition of necroptosis reduces disease severity during secondary bacterial infection. Our results advance our understanding on the molecular basis of co- and secondary bacterial infection to influenza and identify necroptosis inhibition and antioxidant therapy as potential intervention strategies.
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http://dx.doi.org/10.1016/j.celrep.2020.108062DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7570217PMC
August 2020

SARS-CoV-2 may regulate cellular responses through depletion of specific host miRNAs.

Am J Physiol Lung Cell Mol Physiol 2020 09 5;319(3):L444-L455. Epub 2020 Aug 5.

Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama.

Cold viruses have generally been considered fairly innocuous until the appearance of the severe acute respiratory coronavirus 2 (SARS-CoV-2) in 2019, which caused the coronavirus disease 2019 (COVID-19) global pandemic. Two previous viruses foreshadowed that a coronavirus could potentially have devastating consequences in 2002 [severe acute respiratory coronavirus (SARS-CoV)] and in 2012 [Middle East respiratory syndrome coronavirus (MERS-CoV)]. The question that arises is why these viruses are so different from the relatively harmless cold viruses. On the basis of an analysis of the current literature and using bioinformatic approaches, we examined the potential human miRNA interactions with the SARS-CoV-2's genome and compared the miRNA target sites in seven coronavirus genomes that include SARS-CoV-2, MERS-CoV, SARS-CoV, and four nonpathogenic coronaviruses. Here, we discuss the possibility that pathogenic human coronaviruses, including SARS-CoV-2, could modulate host miRNA levels by acting as miRNA sponges to facilitate viral replication and/or to avoid immune responses.
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http://dx.doi.org/10.1152/ajplung.00252.2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7473886PMC
September 2020

Pulmonary surfactant lipids inhibit infections with the pandemic H1N1 influenza virus in several animal models.

J Biol Chem 2020 02 27;295(6):1704-1715. Epub 2019 Dec 27.

Department of Medicine, Program in Cell Biology, National Jewish Health, Denver, Colorado 80206. Electronic address:

The influenza A (H1N1)pdm09 outbreak in 2009 exemplified the problems accompanying the emergence of novel influenza A virus (IAV) strains and their unanticipated virulence in populations with no pre-existing immunity. Neuraminidase inhibitors (NAIs) are currently the drugs of choice for intervention against IAV outbreaks, but there are concerns that NAI-resistant viruses can transmit to high-risk populations. These issues highlight the need for new approaches that address the annual influenza burden. In this study, we examined whether palmitoyl-oleoyl-phosphatidylglycerol (POPG) and phosphatidylinositol (PI) effectively antagonize (H1N1)pdm09 infection. POPG and PI markedly suppressed cytopathic effects and attenuated viral gene expression in (H1N1)pdm09-infected Madin-Darby canine kidney cells. POPG and PI bound to (H1N1)pdm09 with high affinity and disrupted viral spread from infected to noninfected cells in tissue culture and also reduced (H1N1)pdm09 propagation by a factor of 10 after viral infection was established In a mouse infection model of (H1N1)pdm09, POPG and PI significantly reduced lung inflammation and viral burden. Of note, when mice were challenged with a typically lethal dose of 1000 plaque-forming units of (H1N1)pdm09, survival after 10 days was 100% (14 of 14 mice) with the POPG treatment compared with 0% (0 of 14 mice) without this treatment. POPG also significantly reduced inflammatory infiltrates and the viral burden induced by (H1N1)pdm09 infection in a ferret model. These findings indicate that anionic phospholipids potently and efficiently disrupt influenza infections in animal models.
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http://dx.doi.org/10.1074/jbc.RA119.012053DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7008372PMC
February 2020

The influenza NS1 protein modulates RIG-I activation via a strain-specific direct interaction with the second CARD of RIG-I.

J Biol Chem 2020 01 16;295(4):1153-1164. Epub 2019 Dec 16.

Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama 35294

A critical role of influenza A virus nonstructural protein 1 (NS1) is to antagonize the host cellular antiviral response. NS1 accomplishes this role through numerous interactions with host proteins, including the cytoplasmic pathogen recognition receptor, retinoic acid-inducible gene I (RIG-I). Although the consequences of this interaction have been studied, the complete mechanism by which NS1 antagonizes RIG-I signaling remains unclear. We demonstrated previously that the NS1 RNA-binding domain (NS1) interacts directly with the second caspase activation and recruitment domain (CARD) of RIG-I. We also identified that a single strain-specific polymorphism in the NS1 (R21Q) completely abrogates this interaction. Here we investigate the functional consequences of an R21Q mutation on NS1's ability to antagonize RIG-I signaling. We observed that an influenza virus harboring the R21Q mutation in NS1 results in significant up-regulation of RIG-I signaling. In support of this, we determined that an R21Q mutation in NS1 results in a marked deficit in NS1's ability to antagonize TRIM25-mediated ubiquitination of the RIG-I CARDs, a critical step in RIG-I activation. We also observed that WT NS1 is capable of binding directly to the tandem RIG-I CARDs, whereas the R21Q mutation in NS1 significantly inhibits this interaction. Furthermore, we determined that the R21Q mutation does not impede the interaction between NS1 and TRIM25 or NS1's ability to bind RNA. The data presented here offer significant insights into NS1 antagonism of RIG-I and illustrate the importance of understanding the role of strain-specific polymorphisms in the context of this specific NS1 function.
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http://dx.doi.org/10.1074/jbc.RA119.011410DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6983837PMC
January 2020

Matrix metalloproteinase-9 deficiency protects mice from severe influenza A viral infection.

JCI Insight 2018 12 20;3(24). Epub 2018 Dec 20.

Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA.

Matrix metalloproteinase-9 (MMP-9) cleaves various proteins to regulate inflammatory and injury responses. However, MMP-9's activities during influenza A viral (IAV) infections are incompletely understood. Herein, plasma MMP-9 levels were increased in patients with pandemic H1N1 and seasonal IAV infections. MMP-9 lung levels were increased and localized to airway epithelial cells and leukocytes in H1N1-infected WT murine lungs. H1N1-infected Mmp-9-/- mice had lower mortality rates, reduced weight loss, lower lung viral titers, and reduced lung injury, along with lower E-cadherin shedding in bronchoalveolar lavage fluid (BALF) samples than WT mice. H1N1-infected Mmp-9-/- mice had an altered immune response to IAV with lower BALF PMN and macrophage counts, higher Th1-like CD4+ and CD8+ T cell subsets, lower T regulatory cell counts, reduced lung type I interferon levels, and higher lung interferon-γ levels. Mmp-9 bone marrow-chimera studies revealed that Mmp-9 deficiency in lung parenchymal cells protected mice from IAV-induced mortality. H1N1-infected Mmp-9-/- lung epithelial cells had lower viral titers than H1N1-infected WT cells in vitro. Thus, H1N1-infected Mmp-9-/- mice are protected from IAV-induced lung disease due to a more effective adaptive immune response to IAV and reduced epithelial barrier injury due partly to reduced E-cadherin shedding. Thus, we believe that MMP-9 is a novel therapeutic target for IAV infections.
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http://dx.doi.org/10.1172/jci.insight.99022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6338318PMC
December 2018

Influenza-mediated reduction of lung epithelial ion channel activity leads to dysregulated pulmonary fluid homeostasis.

JCI Insight 2018 10 18;3(20). Epub 2018 Oct 18.

Department of Anesthesiology and Perioperative Medicine, Division of Molecular and Translational Biomedicine.

Severe influenza (IAV) infection can develop into bronchopneumonia and edema, leading to acquired respiratory distress syndrome (ARDS) and pathophysiology. Underlying causes for pulmonary edema and aberrant fluid regulation largely remain unknown, particularly regarding the role of viral-mediated mechanisms. Herein, we show that distinct IAV strains reduced the functions of the epithelial sodium channel (ENaC) and the cystic fibrosis transmembrane regulator (CFTR) in murine respiratory and alveolar epithelia in vivo, as assessed by measurements of nasal potential differences and single-cell electrophysiology. Reduced ion channel activity was distinctly limited to virally infected cells in vivo and not bystander uninfected lung epithelium. Multiple lines of evidence indicated ENaC and CFTR dysfunction during the acute infection period; however, only CFTR dysfunction persisted beyond the infection period. ENaC, CFTR, and Na,K-ATPase activities and protein levels were also reduced in virally infected human airway epithelial cells. Reduced ENaC and CFTR led to changes in airway surface liquid morphology of human tracheobronchial cultures and airways of IAV-infected mice. Pharmacologic correction of CFTR function ameliorated IAV-induced physiologic changes. These changes are consistent with mucous stasis and pulmonary edema; furthermore, they indicate that repurposing therapeutic interventions correcting CFTR dysfunction may be efficacious for treatment of IAV lung pathophysiology.
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http://dx.doi.org/10.1172/jci.insight.123467DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6237450PMC
October 2018

ERS/ATS workshop report on respiratory health effects of household air pollution.

Eur Respir J 2018 01 4;51(1). Epub 2018 Jan 4.

University of California School of Public Health, Berkeley, CA, USA.

Exposure to household air pollution (HAP) from solid fuel combustion affects almost half of the world population. Adverse respiratory outcomes such as respiratory infections, impaired lung growth and chronic obstructive pulmonary disease have been linked to HAP exposure. Solid fuel smoke is a heterogeneous mixture of various gases and particulates. Cell culture and animal studies with controlled exposure conditions and genetic homogeneity provide important insights into HAP mechanisms. Impaired bacterial phagocytosis in exposed human alveolar macrophages possibly mediates several HAP-related health effects. Lung pathological findings in HAP-exposed individuals demonstrate greater small airways fibrosis and less emphysema compared with cigarette smokers. Field studies using questionnaires, air pollution monitoring and/or biomarkers are needed to better establish human risks. Some, but not all, studies suggest that improving cookstove efficiency or venting emissions may be associated with reduced respiratory symptoms, lung function decline in women and severe pneumonia in children. Current studies focus on fuel switching, stove technology replacements or upgrades and air filter devices. Several governments have initiated major programmes to accelerate the upgrade from solid fuels to clean fuels, particularly liquid petroleum gas, which provides research opportunities for the respiratory health community.
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http://dx.doi.org/10.1183/13993003.00698-2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7418845PMC
January 2018

Use of ferrets for electrophysiologic monitoring of ion transport.

PLoS One 2017 27;12(10):e0186984. Epub 2017 Oct 27.

Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America.

Limited success achieved in translating basic science discoveries into clinical applications for chronic airway diseases is attributed to differences in respiratory anatomy and physiology, poor approximation of pathologic processes, and lack of correlative clinical endpoints between humans and laboratory animal models. Here, we discuss advantages of using ferrets (Mustela putorus furo) as a model for improved understanding of human airway physiology and demonstrate assays for quantifying airway epithelial ion transport in vivo and ex vivo, and establish air-liquid interface cultures of ferret airway epithelial cells as a complementary in vitro model for mechanistic studies. We present data here that establishes the feasibility of measuring these human disease endpoints in ferrets. Briefly, potential difference across the nasal and the lower airway epithelium in ferrets could be consistently assessed, were highly reproducible, and responsive to experimental interventions. Additionally, ferret airway epithelial cells were amenable to primary cell culture methods for in vitro experiments as was the use of ferret tracheal explants as an ex vivo system for assessing ion transport. The feasibility of conducting multiple assessments of disease outcomes supports the adoption of ferrets as a highly relevant model for research in obstructive airway diseases.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0186984PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5659650PMC
November 2017

Influenza virus infection alters ion channel function of airway and alveolar cells: mechanisms and physiological sequelae.

Am J Physiol Lung Cell Mol Physiol 2017 Nov 3;313(5):L845-L858. Epub 2017 Aug 3.

Department of Anesthesiology and Perioperative Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and

The cystic fibrosis transmembrane conductance regulator (CFTR) and the amiloride-sensitive epithelial sodium channels (ENaC) are located in the apical membranes of airway and alveolar epithelial cells. These transporters play an important role in the regulation of lung fluid balance across airway and alveolar epithelia by being the conduits for chloride (Cl) and bicarbonate ([Formula: see text]) secretion and sodium (Na) ion absorption, respectively. The functional role of these channels in the respiratory tract is to maintain the optimum volume and ionic composition of the bronchial periciliary fluid (PCL) and alveolar lining fluid (ALF) layers. The PCL is required for proper mucociliary clearance of pathogens and debris, and the ALF is necessary for surfactant homeostasis and optimum gas exchange. Dysregulation of ion transport may lead to mucus accumulation, bacterial infections, inflammation, pulmonary edema, and compromised respiratory function. Influenza (or flu) in mammals is caused by influenza A and B viruses. Symptoms include dry cough, sore throat, and is often followed by secondary bacterial infections, accumulation of fluid in the alveolar spaces and acute lung injury. The underlying mechanisms of flu symptoms are not fully understood. This review summarizes our present knowledge of how influenza virus infections alter airway and alveolar epithelial cell CFTR and ENaC function in vivo and in vitro and the role of these changes in influenza pathogenesis.
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http://dx.doi.org/10.1152/ajplung.00244.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5792181PMC
November 2017

ATF4 regulates arsenic trioxide-mediated NADPH oxidase, ER-mitochondrial crosstalk and apoptosis.

Arch Biochem Biophys 2016 Nov 13;609:39-50. Epub 2016 Sep 13.

Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL, USA. Electronic address:

Arsenic is a mitochondrial toxin, and its derivatives, such as arsenic trioxide (ATO), can trigger endoplasmic reticulum (ER) and the associated unfolded protein response (UPR). Here, we show that arsenic induction of the UPR triggers ATF4, which is involved in regulating this ER-mitochondrial crosstalk that is important for the molecular pathogenesis of arsenic toxicity. Employing ATF4 and ATF4 MEFs, we show that ATO induces UPR and impairs mitochondrial integrity in ATF4 MEF cells which is largely ablated upon loss of ATF4. Following ATO treatment, ATF4 activates NADPH oxidase by promoting assembly of the enzyme components Rac-1/P47/P67, which generates ROS/superoxides. Furthermore, ATF4 is required for triggering Ca/calpain/caspase-12-mediated apoptosis following ATO treatment. The IP3R inhibitor attenuates Ca/calpain-dependent apoptosis, as well as reduces m-ROS and MMP disruption, suggesting that ER-mitochondria crosstalk involves IP3R-regulated Ca signaling. Blockade of m-Ca entry by inhibiting m-VDAC reduces ATO-mediated UPR in ATF4 cells. Additionally, ATO treatment leads to p53-regulated mitochondrial apoptosis, where p53 phosphorylation plays a key role. Together, these findings indicate that ATO-mediated apoptosis is regulated by both ER and mitochondria events that are facilitated by ATF4 and the UPR. Thus, we describe novel mechanisms by which ATO orchestrates cytotoxic responses involving interplay of ER and mitochondria.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5077172PMC
http://dx.doi.org/10.1016/j.abb.2016.09.003DOI Listing
November 2016

Activating transcription factor 4 underlies the pathogenesis of arsenic trioxide-mediated impairment of macrophage innate immune functions.

Toxicol Appl Pharmacol 2016 10 25;308:46-58. Epub 2016 Jul 25.

Department of Dermatology and Skin Diseases Research Center, University of Alabama at Birmingham, Birmingham, AL, USA. Electronic address:

Chronic arsenic exposure to humans is considered immunosuppressive with augmented susceptibility to several infectious diseases. The exact molecular mechanisms, however, remain unknown. Earlier, we showed the involvement of unfolded protein response (UPR) signaling in arsenic-mediated impairment of macrophage functions. Here, we show that activating transcription factor 4 (ATF4), a UPR transcription factor, regulates arsenic trioxide (ATO)-mediated dysregulation of macrophage functions. In ATO-treated ATF4(+/+) wild-type mice, a significant down-regulation of CD11b expression was associated with the reduced phagocytic functions of peritoneal and lung macrophages. This severe immuno-toxicity phenotype was not observed in ATO-treated ATF4(+/-) heterozygous mice. To confirm these observations, we demonstrated in Raw 264.7 cells that ATF4 knock-down rescues ATO-mediated impairment of macrophage functions including cytokine production, bacterial engulfment and clearance of engulfed bacteria. Sustained activation of ATF4 by ATO in macrophages induces apoptosis, while diminution of ATF4 expression protects against ATO-induced apoptotic cell death. Raw 264.7 cells treated with ATO also manifest dysregulated Ca(++) homeostasis. ATO induces Ca(++)-dependent calpain-1 and caspase-12 expression which together regulated macrophage apoptosis. Additionally, apoptosis was also induced by mitochondria-regulated pathway. Restoring ATO-impaired Ca(++) homeostasis in ER/mitochondria by treatments with the inhibitors of inositol 1,4,5-trisphosphate receptor (IP3R) and voltage-dependent anion channel (VDAC) attenuate innate immune functions of macrophages. These studies identify a novel role for ATF4 in underlying pathogenesis of macrophage dysregulation and immuno-toxicity of arsenic.
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http://dx.doi.org/10.1016/j.taap.2016.07.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5978774PMC
October 2016

Changes in HPBMC markers of immmune function following controlled short-term inhalation exposures of humans to hardwood smoke.

Inhal Toxicol 2016 ;28(2):61-70

b Lovelace Respiratory Research Institute , Albuquerque , NM , USA , and.

Previous studies have shown that complex mixtures containing particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) produce systemic immunotoxicity in animal models following inhalation exposures. While we and others have shown that emissions associated with hardwood smoke (HWS), cigarette smoke and diesel exhaust can suppress the immune systems of animals in vitro and in vivo, there have been few immune function studies on human peripheral blood mononuclear cells (HPBMC) following exposure of humans to HWS. Our work shows that T cells are an important targets of PM and PAH immunotoxicity. These studies were conducted on HPBMC from 14 human volunteers receiving four 2 h nightly exposures to clean air or HWS at a concentration of 500 ug/m(3). We measured anti-CD3/anti-CD28 stimulated T-cell proliferation and HPBMC cytokine production in cell supernatants, including interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), interleukin 8 (IL-8), TH1 cytokines γIFN and IL-2, TH2 cytokine IL-4, Th17 cytokine interleukin 17A (IL-17A) and interleukin 10 (IL-10). We analyzed results using analysis of variance (ANOVA), t-tests and Pearson correlation. Results showed that there was significant variation in the amount of T-cell proliferation observed following polyclonal activation with anti-CD3/anti-CD28 antibodies in both the air and HWS-exposed groups. There was not a significant effect of HWS on T-cell proliferation. However, we did find a strong relationship between the presence of proinflammatory cytokines (IL-1β, TNF-α, IL-6, but not IL-8) and the amount of T-cell proliferation seen in individual donors, demonstrating that brief exposures of humans to HWS can produce changes in systemic immunity that is associated with proinflammatory cytokines.
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http://dx.doi.org/10.3109/08958378.2015.1136714DOI Listing
December 2016

Depressed Hypoxic and Hypercapnic Ventilatory Responses at Early Stage of Lethal Avian Influenza A Virus Infection in Mice.

PLoS One 2016 25;11(1):e0147522. Epub 2016 Jan 25.

Pathophysiology Program, Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM, 87108, United States of America.

H5N1 virus infection results in ~60% mortality in patients primarily due to respiratory failure, but the underlying causes of mortality are unclear. The goal of this study is to reveal respiratory disorders occurring at the early stage of infection that may be responsible for subsequent respiratory failure and death. BALB/c mice were intranasally infected with one of two H5N1 virus strains: HK483 (lethal) or HK486 (non-lethal) virus. Pulmonary ventilation and the responses to hypoxia (HVR; 7% O2 for 3 min) and hypercapnia (HCVR; 7% CO2 for 5 min) were measured daily at 2 days prior and 1, 2, and 3 days postinfection (dpi) and compared to mortality typically by 8 dpi. At 1, 2, and 3 dpi, immunoreactivities (IR) of substance P (SP-IR) in the nodose ganglion or tyrosine hydroxylase (TH-IR) in the carotid body coupled with the nucleoprotein of influenza A (NP-IR) was examined in some mice, while arterial blood was collected in others. Our results showed that at 2 and 3 dpi: 1) both viral infections failed to alter body temperature and weight, [Formula: see text], or induce viremia while producing similarly high lung viral titers; 2) HK483, but not HK486, virus induced tachypnea and depressed HVR and HCVR without changes in arterial blood pH and gases; and 3) only HK483 virus led to NP-IR in vagal SP-IR neurons, but not in the carotid body, and increased density of vagal SP-IR neurons. In addition, all HK483, rather than HK486, mice died at 6 to 8 dpi and the earlier death was correlated with more severe depression of HVR and HCVR. Our data suggest that tachypnea and depressed HVR/HCVR occur at the early stage of lethal H5N1 viral infection associated with viral replication and increased SP-IR density in vagal neurons, which may contribute to the respiratory failure and death.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0147522PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4725683PMC
July 2016

Bik Mediates Caspase-Dependent Cleavage of Viral Proteins to Promote Influenza A Virus Infection.

Am J Respir Cell Mol Biol 2016 05;54(5):664-73

1 Chronic Obstructive Pulmonary Disease Program, Lovelace Respiratory Research Institute, Albuquerque, New Mexico.

Influenza virus induces apoptosis in infected cells to promote viral replication by manipulating the host cell death signaling pathway. Although some Bcl-2 family proteins play a role in the replication of influenza A virus (IAV), the role of cell death pathways in the viral replication cycle is unclear. We investigated whether deficiency of the proapoptotic Bcl-2 family protein, Bik, plays a role in IAV replication. IAV replication was attenuated in mouse airway epithelial cells (MAECs) from bik(-/-) compared with bik(+/+) mice, as indicated by reduced viral titers. Bik(-/-) MAECs showed more stable transepithelial resistance after infection than did bik(+/+) MAECs, were less sensitive to infection-induced cell death, and released fewer copies of viral RNA. Similar results were obtained when Bik expression was suppressed in human airway epithelial cells (HAECs). Bik(+/+) mice lost weight drastically and died within 8 days of infection, whereas 75% of bik(-/-) mice survived infection for 14 days and were 10-fold less likely to die from infection compared with bik(+/+) mice. IAV infection activated caspase 3 in bik(+/+) but not in bik(-/-) MAECs. Cleavage of viral nucleoprotein and M2 proteins were inhibited in bik(-/-) MAECs and when caspase activation was inhibited in HAECs. Furthermore, Bik deficiency impaired cytoplasmic export of viral ribonucleoprotein. These studies suggest a link between Bik-mediated caspase activation and cleavage of viral proteins. Thus, inhibition of proapoptotic host factors such as Bik and downstream mediators of cell death may represent a novel approach to influenza treatment.
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http://dx.doi.org/10.1165/rcmb.2015-0133OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4942193PMC
May 2016

Renal systems biology of patients with systemic inflammatory response syndrome.

Kidney Int 2015 Oct 20;88(4):804-14. Epub 2015 May 20.

National Center for Genome Resources, Santa Fe, New Mexico, USA.

A systems biology approach was used to comprehensively examine the impact of renal disease and hemodialysis (HD) on patient response during critical illness. To achieve this, we examined the metabolome, proteome, and transcriptome of 150 patients with critical illness, stratified by renal function. Quantification of plasma metabolites indicated greater change as renal function declined, with the greatest derangements in patients receiving chronic HD. Specifically, 6 uremic retention molecules, 17 other protein catabolites, 7 modified nucleosides, and 7 pentose phosphate sugars increased as renal function declined, consistent with decreased excretion or increased catabolism of amino acids and ribonucleotides. Similarly, the proteome showed increased levels of low-molecular-weight proteins and acute-phase reactants. The transcriptome revealed a broad-based decrease in mRNA levels among patients on HD. Systems integration revealed an unrecognized association between plasma RNASE1 and several RNA catabolites and modified nucleosides. Further, allantoin, N1-methyl-4-pyridone-3-carboxamide, and N-acetylaspartate were inversely correlated with the majority of significantly downregulated genes. Thus, renal function broadly affected the plasma metabolome, proteome, and peripheral blood transcriptome during critical illness; changes were not effectively mitigated by hemodialysis. These studies allude to several novel mechanisms whereby renal dysfunction contributes to critical illness.
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http://dx.doi.org/10.1038/ki.2015.150DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4591107PMC
October 2015

Ebola: history, treatment, and lessons from a new emerging pathogen.

Authors:
Kevin S Harrod

Am J Physiol Lung Cell Mol Physiol 2015 Feb 12;308(4):L307-13. Epub 2014 Dec 12.

Department of Anesthesiology, School of Medicine, University of Alabama-Birmingham, Birmingham, Alabama

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http://dx.doi.org/10.1152/ajplung.00354.2014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4329468PMC
February 2015

Integrative "omic" analysis of experimental bacteremia identifies a metabolic signature that distinguishes human sepsis from systemic inflammatory response syndromes.

Am J Respir Crit Care Med 2014 Aug;190(4):445-55

1 Respiratory Immunology Program.

Rationale: Sepsis is a leading cause of morbidity and mortality. Currently, early diagnosis and the progression of the disease are difficult to make. The integration of metabolomic and transcriptomic data in a primate model of sepsis may provide a novel molecular signature of clinical sepsis.

Objectives: To develop a biomarker panel to characterize sepsis in primates and ascertain its relevance to early diagnosis and progression of human sepsis.

Methods: Intravenous inoculation of Macaca fascicularis with Escherichia coli produced mild to severe sepsis, lung injury, and death. Plasma samples were obtained before and after 1, 3, and 5 days of E. coli challenge and at the time of killing. At necropsy, blood, lung, kidney, and spleen samples were collected. An integrative analysis of the metabolomic and transcriptomic datasets was performed to identify a panel of sepsis biomarkers.

Measurements And Main Results: The extent of E. coli invasion, respiratory distress, lethargy, and mortality was dependent on the bacterial dose. Metabolomic and transcriptomic changes characterized severe infections and death, and indicated impaired mitochondrial, peroxisomal, and liver functions. Analysis of the pulmonary transcriptome and plasma metabolome suggested impaired fatty acid catabolism regulated by peroxisome-proliferator activated receptor signaling. A representative four-metabolite model effectively diagnosed sepsis in primates (area under the curve, 0.966) and in two human sepsis cohorts (area under the curve, 0.78 and 0.82).

Conclusions: A model of sepsis based on reciprocal metabolomic and transcriptomic data was developed in primates and validated in two human patient cohorts. It is anticipated that the identified parameters will facilitate early diagnosis and management of sepsis.
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http://dx.doi.org/10.1164/rccm.201404-0624OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4214130PMC
August 2014

The rapid and sustained responses of dendritic cells to influenza virus infection in a non-human primate model.

Braz J Infect Dis 2014 Jul-Aug;18(4):406-13. Epub 2014 Apr 26.

Infectious Disease Program, Lovelace Respiratory Research Institute, Albuquerque, NM, USA. Electronic address:

Dendritic cells (DCs) are readily infected by influenza viruses and play a crucial role in regulating host innate and adaptive immune responses to viral infection. The aims of this study are to characterize the dynamic changes in the numbers and maturation status of dendritic cells present in the lung and lung-associated lymph nodes (LALNs) in the model of a non-human primate (NHP) infected by influenza A virus (IAV). Cynomolgus macaques were infected with influenza A virus (H3N2) via bronchoscopy. Flow cytometry was used to analyze the DC numbers, maturation status and subsets during the time of acute infection (days 1, 2, 3, 4, 7) and the resolution phase (day 30). A dramatic increase in the numbers of influenza A virus-infected CD11c+CD14- myeloid dendritic cells (mDCs) and CD11c-CD123+ plasmacytoid dendritic cells (pDCs) were observed from day 1 to day 4 and peak up from day 7 post-infection. In lung and lung-associated lymph nodes, the numbers and maturation status of myeloid dendritic cells and plasmacytoid dendritic cells increased more slowly than those in the lung tissues. On day 30 post-infection, influenza A virus challenge increased the number of myeloid dendritic cells, but not plasmacytoid dendritic cells, compared with baseline. These findings indicate that dendritic cells are susceptible to influenza A virus infection, with the likely purpose of increasing mature myeloid dendritic cells numbers in the lung and lung and lung-associated lymph nodes, which provides important new insights into the regulation of dendritic cells in a non-human primate model.
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http://dx.doi.org/10.1016/j.bjid.2013.12.008DOI Listing
October 2014

Enhanced viral replication and modulated innate immune responses in infant airway epithelium following H1N1 infection.

J Virol 2014 Jul 16;88(13):7412-25. Epub 2014 Apr 16.

California National Primate Research Center, University of California, Davis, California, USA Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, California, USA

Unlabelled: Influenza is the cause of significant morbidity and mortality in pediatric populations. The contribution of pulmonary host defense mechanisms to viral respiratory infection susceptibility in very young children is poorly understood. As a surrogate to compare mucosal immune responses of infant and adult lungs, rhesus monkey primary airway epithelial cell cultures were infected with pandemic influenza A/H1N1 virus in vitro. Virus replication, cytokine secretion, cell viability, and type I interferon (IFN) pathway PCR array profiles were evaluated for both infant and adult cultures. In comparison with adult cultures, infant cultures showed significantly increased levels of H1N1 replication, reduced alpha interferon (IFN-α) protein synthesis, and no difference in cell death following infection. Age-dependent differences in expression levels of multiple genes associated with the type I IFN pathway were observed in H1N1-infected cultures. To investigate the pulmonary and systemic responses to H1N1 infection in early life, infant monkeys were inoculated with H1N1 by upper airway administration. Animals were monitored for virus and parameters of inflammation over a 14-day period. High H1N1 titers were recovered from airways at day 1, with viral RNA remaining detectable until day 9 postinfection. Despite viral clearance, bronchiolitis and alveolitis persisted at day 14 postinfection; histopathological analysis revealed alveolar septal thickening and intermittent type II pneumocyte hyperplasia. Our overall findings are consistent with the known susceptibility of pediatric populations to respiratory virus infection and suggest that intrinsic developmental differences in airway epithelial cell immune function may contribute to the limited efficacy of host defense during early childhood.

Importance: To the best of our knowledge, this study represents the first report of intrinsic developmental differences in infant airway epithelial cells that may contribute to the increased susceptibility of the host to respiratory virus infections. Despite the global burden of influenza, there are currently no vaccine formulations approved for children <6 months of age. Given the challenges of conducting experimental studies involving pediatric patients, rhesus monkeys are an ideal laboratory animal model to investigate the maturation of pulmonary mucosal immune mechanisms during early life because they are most similar to those of humans with regard to postnatal maturation of the lung structure and the immune system. Thus, our findings are highly relevant to translational medicine, and these data may ultimately lead to novel approaches that enhance airway immunity in very young children.
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http://dx.doi.org/10.1128/JVI.00188-14DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4054429PMC
July 2014

Severe acute respiratory syndrome-coronavirus infection in aged nonhuman primates is associated with modulated pulmonary and systemic immune responses.

Immun Ageing 2014 Mar 19;11(1). Epub 2014 Mar 19.

Work performed at Lovelace Respiratory Research Institute (LRRI), Infectious Disease Program, Albuquerque, NM, Mexico.

Background: Many respiratory viruses disproportionately impact the elderly. Likewise, advanced age correlated with more adverse disease outcomes following severe acute respiratory syndrome coronavirus (SARS-CoV) infection in humans. We used an aged African green monkey SARS-CoV infection model to better understand age-related mechanisms of increased susceptibility to viral respiratory infections. Nonhuman primates are critical translational models for such research given their similarities to humans in immune-ageing as well as lung structure.

Results: Significant age- and infection-dependent differences were observed in both systemic and mucosal immune compartments. Peripheral lymphocytes, specifically CD8 T and B cells were significantly lower in aged monkeys pre- and post- SARS-CoV infection, while neutrophil and monocyte numbers were not impacted by age or infection status. Serum proinflammatory cytokines were similar in both age groups, whereas significantly lower levels of IL-1beta, IL-18, IL-6, IL-12 and IL-15 were detected in the lungs of SARS-CoV-infected aged monkeys at either 5 or 10 days post infection. Total lung leukocyte numbers and relative frequency of CD8 T cells, B cells, macrophages and dendritic cells were greatly reduced in the aged host during SARS-CoV infection, despite high levels of chemoattractants for many of these cells in the aged lung. Dendritic cells and monocytes/macrophages showed age-dependent differences in activation and chemokine receptor profiles, while the CD8 T cell and B cell responses were significantly reduced in the aged host. In examination of viral titers, significantly higher levels of SARS-CoV were detected in the nasal swabs early, at day 1 post infection, in aged as compared to juvenile monkeys, but virus levels were only slightly higher in aged animals by day 3. Although there was a trend of higher titers in respiratory tissues at day 5 post infection, this did not reach statistical significance and virus was cleared from all animals by day 10, regardless of age.

Conclusions: This study provides unique insight into how several parameters of the systemic and mucosal immune response to SARS-CoV infection are significantly modulated by age. These immune differences may contribute to deficient immune function and the observed trend of higher SARS-CoV replication in aged nonhuman primates.
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http://dx.doi.org/10.1186/1742-4933-11-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999990PMC
March 2014

Human metapneumovirus inhibits the IL-6-induced JAK/STAT3 signalling cascade in airway epithelium.

J Gen Virol 2014 Jan 10;95(Pt 1):26-37. Epub 2013 Oct 10.

Infectious Diseases Program, Lovelace Respiratory Research Institute, Albuquerque, NM, USA.

The host cytokine IL-6 plays an important role in host defence and prevention of lung injury from various pathogens, making IL-6 an important mediator in the host's susceptibility to respiratory infections. The cellular response to IL-6 is mediated through a Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) signal transduction pathway. Human metapneumovirus (hMPV) is an important causative agent of viral respiratory infections known to inhibit the IFN-mediated activation of STAT1. However, little is known about the interactions between this virus and other STAT signalling cascades. Herein, we showed that hMPV can attenuate the IL-6-mediated JAK/STAT3 signalling cascade in lung epithelial cells. HMPV inhibited a key event in this pathway by impeding the phosphorylation and nuclear translocation of STAT3 in A549 cells and in primary normal human bronchial epithelial cells. Further studies established that hMPV interrupted the IL-6-induced JAK/STAT pathway early in the signal transduction pathway by blocking the phosphorylation of JAK2. By antagonizing the IL-6-mediated JAK/STAT3 pathway, hMPV perturbed the expression of IL-6-inducible genes important for apoptosis, cell differentiation and growth. Infection with hMPV also differentially regulated the effects of IL-6 on apoptosis. Thus, hMPV regulation of these genes could usurp the protective roles of IL-6, and these data provide insight into an important element of viral pathogenesis.
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http://dx.doi.org/10.1099/vir.0.055632-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5974310PMC
January 2014

Gestational exposure of mice to secondhand cigarette smoke causes bronchopulmonary dysplasia blocked by the nicotinic receptor antagonist mecamylamine.

Environ Health Perspect 2013 Aug 11;121(8):957-64. Epub 2013 Jun 11.

Lovelace Respiratory Research Institute, Albuquerque, New Mexico, USA.

Background: Cigarette smoke (CS) exposure during gestation may increase the risk of bronchopulmonary dysplasia (BPD)-a developmental lung condition primarily seen in neonates that is characterized by hypoalveolarization, decreased angiogenesis, and diminished surfactant protein production and may increase the risk of chronic obstructive pulmonary disease.

Objective: We investigated whether gestational exposure to secondhand CS (SS) induced BPD and sought to ascertain the role of nicotinic acetylcholine receptors (nAChRs) in this response.

Methods: We exposed BALB/c and C57BL/6 mice to filtered air (control) or SS throughout the gestation period or postnatally up to 10 weeks. Lungs were examined at 7 days, 10 weeks, and 8 months after birth.

Results: Gestational but not postnatal exposure to SS caused a typical BPD-like condition: suppressed angiogenesis [decreased vascular endothelial growth factor (VEGF), VEGF receptor, and CD34/CD31 (hematopoietic progenitor cell marker/endothelial cell marker)], irreversible hypoalveolarization, and significantly decreased levels of Clara cells, Clara cell secretory protein, and surfactant proteins B and C, without affecting airway ciliated cells. Importantly, concomitant exposure to SS and the nAChR antagonist mecamylamine during gestation blocked the development of BPD.

Conclusions: Gestational exposure to SS irreversibly disrupts lung development leading to a BPD-like condition with hypoalveolarization, decreased angiogenesis, and diminished lung secretory function. Nicotinic receptors are critical in the induction of gestational SS-induced BPD, and the use of nAChR antagonists during pregnancy may block CS-induced BPD.
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http://dx.doi.org/10.1289/ehp.1306611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3734504PMC
August 2013

Neurovirulence of H5N1 infection in ferrets is mediated by multifocal replication in distinct permissive neuronal cell regions.

PLoS One 2012 8;7(10):e46605. Epub 2012 Oct 8.

Infectious Diseases Program, Lovelace Respiratory Research Institute, Albuquerque, New Mexico, USA.

Highly pathogenic avian influenza A (HPAI), subtype H5N1, remains an emergent threat to the human population. While respiratory disease is a hallmark of influenza infection, H5N1 has a high incidence of neurological sequelae in many animal species and sporadically in humans. We elucidate the temporal/spatial infection of H5N1 in the brain of ferrets following a low dose, intranasal infection of two HPAI strains of varying neurovirulence and lethality. A/Vietnam/1203/2004 (VN1203) induced mortality in 100% of infected ferrets while A/Hong Kong/483/1997 (HK483) induced lethality in only 20% of ferrets, with death occurring significantly later following infection. Neurological signs were prominent in VN1203 infection, but not HK483, with seizures observed three days post challenge and torticollis or paresis at later time points. VN1203 and HK483 replication kinetics were similar in primary differentiated ferret nasal turbinate cells, and similar viral titers were measured in the nasal turbinates of infected ferrets. Pulmonary viral titers were not different between strains and pathological findings in the lungs were similar in severity. VN1203 replicated to high titers in the olfactory bulb, cerebral cortex, and brain stem; whereas HK483 was not recovered in these tissues. VN1203 was identified adjacent to and within the olfactory nerve tract, and multifocal infection was observed throughout the frontal cortex and cerebrum. VN1203 was also detected throughout the cerebellum, specifically in Purkinje cells and regions that coordinate voluntary movements. These findings suggest the increased lethality of VN1203 in ferrets is due to increased replication in brain regions important in higher order function and explains the neurological signs observed during H5N1 neurovirulence.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0046605PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3466300PMC
June 2013

Lack of innate interferon responses during SARS coronavirus infection in a vaccination and reinfection ferret model.

PLoS One 2012 24;7(9):e45842. Epub 2012 Sep 24.

Division of Experimental Therapeutics, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.

In terms of its highly pathogenic nature, there remains a significant need to further define the immune pathology of SARS-coronavirus (SARS-CoV) infection, as well as identify correlates of immunity to help develop vaccines for severe coronaviral infections. Here we use a SARS-CoV infection-reinfection ferret model and a functional genomics approach to gain insight into SARS immunopathogenesis and to identify correlates of immune protection during SARS-CoV-challenge in ferrets previously infected with SARS-CoV or immunized with a SARS virus vaccine. We identified gene expression signatures in the lungs of ferrets associated with primary immune responses to SARS-CoV infection and in ferrets that received an identical second inoculum. Acute SARS-CoV infection prompted coordinated innate immune responses that were dominated by antiviral IFN response gene (IRG) expression. Reinfected ferrets, however, lacked the integrated expression of IRGs that was prevalent during acute infection. The expression of specific IRGs was also absent upon challenge in ferrets immunized with an inactivated, Al(OH)(3)-adjuvanted whole virus SARS vaccine candidate that protected them against SARS-CoV infection in the lungs. Lack of IFN-mediated immune enhancement in infected ferrets that were previously inoculated with, or vaccinated against, SARS-CoV revealed 9 IRG correlates of protective immunity. This data provides insight into the molecular pathogenesis of SARS-CoV and SARS-like-CoV infections and is an important resource for the development of CoV antiviral therapeutics and vaccines.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0045842PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3454321PMC
February 2013

Role of nicotinic receptors and acetylcholine in mucous cell metaplasia, hyperplasia, and airway mucus formation in vitro and in vivo.

J Allergy Clin Immunol 2012 Sep 9;130(3):770-780.e11. Epub 2012 May 9.

Lovelace Respiratory Research Institute, Albuquerque, NM 87108, USA.

Background: Airway mucus hypersecretion is a key pathophysiologic feature in a number of lung diseases. Cigarette smoke/nicotine and allergens are strong stimulators of airway mucus; however, the mechanism of mucus modulation is unclear.

Objectives: We sought to characterize the pathway by which cigarette smoke/nicotine regulates airway mucus and identify agents that decrease airway mucus.

Methods: IL-13 and γ-aminobutyric acid type A receptors (GABA(A)Rs) are implicated in airway mucus. We examined the role of IL-13 and GABA(A)Rs in nicotine-induced mucus formation in normal human bronchial epithelial (NHBE) and A549 cells and secondhand cigarette smoke-induced, ovalbumin-induced, or both mucus formation in vivo.

Results: Nicotine promotes mucus formation in NHBE cells; however, the nicotine-induced mucus formation is independent of IL-13 but sensitive to the GABA(A)R antagonist picrotoxin. Airway epithelial cells express α7-, α9-, and α10-nicotinic acetylcholine receptors (nAChRs), and specific inhibition or knockdown of α7- but not α9/α10-nAChRs abrogates mucus formation in response to nicotine and IL-13. Moreover, addition of acetylcholine or inhibition of its degradation increases mucus in NHBE cells. Nicotinic but not muscarinic receptor antagonists block allergen- or nicotine/cigarette smoke-induced airway mucus formation in NHBE cells, murine airways, or both.

Conclusions: Nicotine-induced airway mucus formation is independent of IL-13, and α7-nAChRs are critical in airway mucous cell metaplasia/hyperplasia and mucus production in response to various promucoid agents, including IL-13. In the absence of nicotine, acetylcholine might be the biological ligand for α7-nAChRs to trigger airway mucus formation. α7-nAChRs are downstream of IL-13 but upstream of GABA(A)Rα2 in the MUC5AC pathway. Acetylcholine and α7-nAChRs might serve as therapeutic targets to control airway mucus.
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http://dx.doi.org/10.1016/j.jaci.2012.04.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3419772PMC
September 2012

Primary severe acute respiratory syndrome coronavirus infection limits replication but not lung inflammation upon homologous rechallenge.

J Virol 2012 Apr 15;86(8):4234-44. Epub 2012 Feb 15.

Lovelace Respiratory Research Institute, Infectious Disease Program, Albuquerque, New Mexico, USA.

Our knowledge regarding immune-protective and immunopathogenic events in severe acute respiratory syndrome coronavirus (SARS-CoV) infection is limited, and little is known about the dynamics of the immune response at the primary site of disease. Here, an African green monkey (AGM) model was used to elucidate immune mechanisms that facilitate viral clearance but may also contribute to persistent lung inflammation following SARS-CoV infection. During primary infection, SARS-CoV replicated in the AGM lung for up to 10 days. Interestingly, lung inflammation was more prevalent following viral clearance, as leukocyte numbers peaked at 14 days postinfection (dpi) and remained elevated at 28 dpi compared to those of mock-infected controls. Lung macrophages but not dendritic cells were rapidly activated, and both cell types had high activation marker expression at late infection time points. Lung proinflammatory cytokines were induced at 1 to 14 dpi, but most returned to baseline by 28 dpi except interleukin 12 (IL-12) and gamma interferon. In SARS-CoV homologous rechallenge studies, 11 of the 12 animals were free of replicating virus at day 5 after rechallenge. However, incidence and severity of lung inflammation was not reduced despite the limited viral replication upon rechallenge. Evaluating the role of antibodies in immune protection or potentiation revealed a progressive increase in anti-SARS-CoV antibodies in lung and serum that did not correlate temporally or spatially with enhanced viral replication. This study represents one of the first comprehensive analyses of lung immunity, including changes in leukocyte populations, lung-specific cytokines, and antibody responses following SARS-CoV rechallenge in AGMs.
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http://dx.doi.org/10.1128/JVI.06791-11DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3318632PMC
April 2012