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Somatic KRAS mutations are the most common oncogenic variants in lung cancer and are associated with poor prognosis. Using a Kras-induced lung cancer mouse model, CC-LR, we previously showed a role for inflammation in lung tumorigenesis through activation of the NF-κB pathway, along with induction of interleukin 6 (IL6) and an IL17-producing CD4+ T-helper cell response. IL22 is an effector molecule secreted by CD4+ and γδ T cells that we previously found to be expressed in CC-LR mice. IL22 mostly signals through the STAT3 pathway and is thought to act exclusively on nonhematopoietic cells with basal IL22 receptor (IL22R) expression on epithelial cells. Here, we found that higher expression of IL22R1 in patients with KRAS-mutant lung adenocarcinoma was an independent indicator of poor recurrence-free survival. We then showed that genetic ablation of Il22 in CC-LR mice (CC-LR/IL22KO mice) caused a significant reduction in tumor number and size. This was accompanied by significantly lower tumor cell proliferation, angiogenesis, and STAT3 activation. Il22 ablation was also associated with significant reduction in lung-infiltrating inflammatory cells and expression of protumor inflammatory cytokines. Conversely, this was accompanied with increased antitumor Th1 and cytotoxic CD8+ T-cell responses, while suppressing the protumor immunosuppressive T regulatory cell response. In CC-LR/IL22KO mice, we found significantly reduced expression of core stemness genes and the number of prototypical SPC+CCSP+ stem cells. Thus, we conclude that IL22 promotes Kras-mutant lung tumorigenesis by driving a protumor inflammatory microenvironment with proliferative, angiogenic, and stemness contextual cues in epithelial/tumor cells. Cancer Immunol Res; 6(7); 788–97. ©2018 AACR.

This file Includes 2 figures and one table as follow: 1: Supplementary figure S1 showing relative IL-22 mRNA expression (S1A), mutant K-ras protein expression (S1B), representative T regulatory cell flow cytometry plot (S1C), and total CD4 and CD8 flow cytometry plots (S1D) 2: Supplementary figure S2 showing pSTAT3 immunohistochemistry (S2A) and T cell related transcription factor mRNA expression (S2B) 3: Supplementary Table S1: List of Q-PCR primers and sequences

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has resulted in a global pandemic with severe socioeconomic effects. Immunopathogenesis of COVID-19 leads to acute respiratory distress syndrome (ARDS) and organ failure. Binding of SARS-CoV-2 spike protein to human angiotensin-converting enzyme 2 (hACE2) on bronchiolar and alveolar epithelial cells triggers host inflammatory pathways that lead to pathophysiological changes. Proinflammatory cytokines and type I interferon (IFN) signaling in alveolar epithelial cells counter barrier disruption, modulate host innate immune response to induce chemotaxis, and initiate the resolution of inflammation. Here, we discuss experimental models to study SARS-CoV-2 infection, molecular pathways involved in SARS-CoV-2-induced inflammation, and viral hijacking of anti-inflammatory pathways, such as delayed type-I IFN response. Mechanisms of alveolar adaptation to hypoxia, adenosinergic signaling, and regulatory microRNAs are discussed as potential therapeutic targets for COVID-19.

Pneumonia is a worldwide threat, making discovery of novel means to combat lower respiratory tract infections an urgent need. We have previously shown that manipulating the lungs’ intrinsic host defenses by therapeutic delivery of a unique dyad of pathogen-associated molecular patterns protects mice against pneumonia in a reactive oxygen species (ROS)-dependent manner. Here we show that antimicrobial ROS are induced from lung epithelial cells by interactions of CpG oligodeoxynucleotides (ODNs) with mitochondrial voltage-dependent anion channel 1 (VDAC1) without dependence on Toll-like receptor 9 (TLR9). The ODN-VDAC1 interaction alters cellular ATP/ADP/AMP localization, increases delivery of electrons to the electron transport chain (ETC), enhances mitochondrial membrane potential (ΔΨm), and differentially modulates ETC complex activities. These combined effects promote leak of electrons from ETC complex III, resulting in superoxide formation. The ODN-induced mitochondrial ROS yield protective antibacterial effects. Together, these studies identify a therapeutic metabolic manipulation strategy that has the potential to broadly protect patients against pneumonia during periods of peak vulnerability without reliance on currently available antibiotics.Author SummaryPneumonia is a major cause of death worldwide. Increasing antibiotic resistance and expanding immunocompromised populations continue to enhance the clinical urgency to find new strategies to prevent and treat pneumonia. We have identified a novel inhaled therapeutic that stimulates lung epithelial defenses to protect mice against pneumonia in a manner that depends on production of reactive oxygen species (ROS). Here, we report that the induction of protective ROS from lung epithelial mitochondria occurs following the interaction of one component of the treatment, an oligodeoxynucleotide, with the mitochondrial voltage-dependent anion channel 1. This interaction alters energy transfer between the mitochondria and the cytosol, resulting in metabolic reprogramming that drives more electrons into the electron transport chain, then causes electrons to leak from the electron transport chain to form protective ROS. While antioxidant therapies are endorsed in many other disease states, we present here an example of therapeutic induction of ROS that is associated with broad protection against pneumonia without reliance on administration of antibiotics.

The Toll-like receptor (TLR) adaptor protein MyD88 is integral to airway inflammatory response to microbial-enriched organic dust extract (ODE) exposures. ODE-induced airway neutrophil influx and release of pro-inflammatory cytokines was essentially abrogated in global MyD88-deficient mice, yet these mice demonstrate an increase in airway epithelial cell mucin expression. To further elucidate the role of MyD88-dependent responses specific to lung airway epithelial cells in response to ODE in vivo, the surfactant protein C protein (SPC) Cre+ embryologic expressing airway epithelial cells floxed for MyD88 to disrupt MyD88 signaling were utilized. The inducible club cell secretory protein (CCSP) Cre+, MyD88 floxed, were also developed. Using an established protocol, mice were intranasally instilled with ODE or saline once or daily up to 3 weeks. Mice with MyD88-deficient SPC+ lung epithelial cells exhibited decreased neutrophil influx following ODE exposure once and repetitively for 1 week without modulation of classic pro-inflammatory mediators including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and neutrophil chemoattractants. This protective response was lost after 3 weeks of repetitive exposure. ODE-induced Muc5ac mucin expression at 1 week was also reduced in MyD88-deficient SPC+ cells. Acute ODE-induced IL-33 was reduced in MyD88-deficient SPC+ cells whereas serum IgE levels were increased at one week. In contrast, mice with inducible MyD88-deficient CCSP+ airway epithelial cells demonstrated no significant difference in experimental indices following ODE exposure. Collectively, these findings suggest that MyD88-dependent signaling targeted to all airway epithelial cells plays an important role in mediating neutrophil influx and mucin production in response to acute organic dust exposures.

Background Signifying the 2-compartments/1-disease paradigm, allergic rhinoconjunctivitis (ARC) and asthma (AA) are prevalent, comorbid conditions triggered by environmental factors (eg, house dust mites [HDMs]). However, despite the ubiquity of triggers, progression to severe ARC/AA is infrequent, suggesting either resilience or adaptation. Objective We sought to determine whether ARC/AA severity relates to maladaptive responses to disease triggers. Methods Adults with HDM-associated ARC were challenged repetitively with HDMs in an aeroallergen challenge chamber. Mechanistic traits associated with disease severity were identified. Results HDM challenges evoked maladaptive (persistently higher ARC symptoms), adaptive (progressive symptom reduction), and resilient (resistance to symptom induction) phenotypes. Symptom severity in the natural environment was an imprecise correlate of the phenotypes. Nasal airway traits, defined by low inflammation-effectual epithelial integrity, moderate inflammation-effectual epithelial integrity, and higher inflammation-ineffectual epithelial integrity, were hallmarks of the resilient, adaptive, and maladaptive evoked phenotypes, respectively. Highlighting a crosstalk mechanism, peripheral blood inflammatory tone calibrated these traits: ineffectual epithelial integrity associated with CD8+ T cells, whereas airway inflammation associated with both CD8+ T cells and eosinophils. Hallmark peripheral blood maladaptive traits were increased natural killer and CD8+ T cells, lower CD4+ mucosal-associated invariant T cells, and deficiencies along the TLR-IRF-IFN antiviral pathway. Maladaptive traits tracking HDM-associated ARC also contributed to AA risk and severity models. Conclusions Repetitive challenges with HDMs revealed that maladaptation to disease triggers may underpin ARC/AA disease severity. A combinatorial therapeutic approach may involve reversal of loss-of-beneficial-function traits (ineffectual epithelial integrity, TLR-IRF-IFN deficiencies), mitigation of gain-of-adverse-function traits (inflammation), and blocking of a detrimental crosstalk between the peripheral blood and airway compartments.

Pneumonia causes a significant burden of disease worldwide. Although all populations are at risk of pneumonia, those at extremes of age and those with immunosuppressive disorders, underlying respiratory disease, and critical illness are particularly vulnerable. Although clinical practice guidelines addressing the management and treatment of pneumonia exist, few of the supporting studies focus on the crucial contributions of the host in pneumonia pathogenesis and recovery. Such essential considerations include the host risk factors that lead to susceptibility to lung infections; biomarkers reflecting the host response and the means to pursue host-directed pneumonia therapy; systemic effects of pneumonia on the host; and long-term health outcomes after pneumonia. To address these gaps, the Pneumonia Working Group of the Assembly on Pulmonary Infection and Tuberculosis led a workshop held at the American Thoracic Society meeting in May 2018 with overarching objectives to foster attention, stimulate research, and promote funding for short-term and long-term investigations into the host contributions to pneumonia. The workshop involved participants from various disciplines with expertise in lung infection, pneumonia, sepsis, immunocompromised patients, translational biology, data science, genomics, systems biology, and clinical trials. This workshop report summarizes the presentations and discussions and important recommendations for future clinical pneumonia studies. These recommendations include establishing consensus disease and outcome definitions, improved phenotyping, development of clinical study networks, standardized data and biospecimen collection and protocols, and development of innovative trial designs.

We have shown that membrane-associated guanylate kinase with inverted domain structure-1 (MAGI1), a scaffold protein with six PSD95/DiscLarge/ZO-1 (PDZ) domains, is involved in the regulation of endothelial cell (EC) activation and atherogenesis in mice. In addition to causing acute respiratory disease, influenza A virus (IAV) infection plays an important role in atherogenesis and triggers acute coronary syndromes and fatal myocardial infarction. Therefore, the aim of this study is to investigate the function and regulation of MAGI1 in IAV-induced EC activation. Whereas, EC infection by IAV increases MAGI1 expression, MAGI1 depletion suppresses IAV infection, suggesting that the induction of MAGI1 may promote IAV infection. Treatment of ECs with oxidized low-density lipoprotein (OxLDL) increases MAGI1 expression and IAV infection, suggesting that MAGI1 is part of the mechanistic link between serum lipid levels and patient prognosis following IAV infection. Our microarray studies suggest that MAGI1-depleted ECs increase protein expression and signaling networks involve in interferon (IFN) production. Specifically, infection of MAGI1-null ECs with IAV upregulates expression of signal transducer and activator of transcription 1 (STAT1), interferon b1 (IFNb1), myxovirus resistance protein 1 (MX1) and 2′-5′-oligoadenylate synthetase 2 (OAS2), and activate STAT5. By contrast, MAGI1 overexpression inhibits Ifnb1 mRNA and MX1 expression, again supporting the pro-viral response mediated by MAGI1. MAGI1 depletion induces the expression of MX1 and virus suppression. The data suggests that IAV suppression by MAGI1 depletion may, in part, be due to MX1 induction. Lastly, interferon regulatory factor 3 (IRF3) translocates to the nucleus in the absence of IRF3 phosphorylation, and IRF3 SUMOylation is abolished in MAGI1-depleted ECs. The data suggests that MAGI1 inhibits IRF3 activation by maintaining IRF3 SUMOylation. In summary, IAV infection occurs in ECs in a MAGI1 expression-dependent manner by inhibiting anti-viral responses including STATs and IRF3 activation and subsequent MX1 induction, and MAGI1 plays a role in EC activation, and in upregulating a pro-viral response. Therefore, the inhibition of MAGI1 is a potential therapeutic target for IAV-induced cardiovascular disease.

During hypoxia or inflammation, extracellular adenosine levels are elevated. Studies using pharmacologic approaches or genetic animal models pertinent to extracellular adenosine signaling implicate this pathway in attenuating hypoxia-associated inflammation. There are four distinct adenosine receptors. Of these, it is not surprising that the Adora2b adenosine receptor functions as an endogenous feedback loop to control hypoxia-associated inflammation. First, Adora2b activation requires higher adenosine concentrations compared to other adenosine receptors, similar to those achieved during hypoxic inflammation. Second, Adora2b is transcriptionally induced during hypoxia or inflammation by hypoxia-inducible transcription factor HIF1A. Studies seeking an alternative adenosine receptor activation mechanism have linked netrin-1 with Adora2b. Netrin-1 was originally discovered as a neuronal guidance molecule but also functions as an immune-modulatory signaling molecule. Similar to Adora2b, netrin-1 is induced by HIF1A, and has been shown to enhance Adora2b signaling. Studies of acute respiratory distress syndrome (ARDS), intestinal inflammation, myocardial or hepatic ischemia and reperfusion implicate the netrin-Adora2b link in tissue protection. In this review, we will discuss the potential molecular linkage between netrin-1 and Adora2b, and explore studies demonstrating interactions between netrin-1 and Adora2b in attenuating tissue inflammation.

When influenza virus infects cells, it changes cellular metabolism in such a way that allows virus particles to replicate efficiently. This metabolic engineering takes place soon after virus infects cells, for which the PSD95/DiscLarge/ZO-1 (PDZ) domain of certain proteins is known to play a role. Membrane-associated guanylate kinase with inverted domain structure-1 (MAGI1) is a scaffold protein with 6 PDZ domains, and we have shown that it is involved in the regulation of endothelial cell (EC) activation and atherosclerosis in mice. Since recent studies indicate that the vascular endothelium can be infected by influenza A virus (IAV) and plays a role in the influenza-induced pathogenesis and cardiovascular disease (CVD), we investigated the role of MAGI1 in IAV infection using cultured human umbilical vein endothelial cells (HUVECs) as well as human lung microvascular endothelial cells (HULECs). We found increased MAGI1 mRNA expression in IAV-infected cells. Conversely, when MAGI1 depleted ECs were infected with IAV, virus infection and replication was greatly suppressed. Our microarray studies revealed that depletion of MAGI1 in HUVECs increased the protein expression and signaling networks involved in interferon production. Specifically, we found that the MAGI1 null condition induced expression of anti-viral response genes including interferon-induced GTP-binding protein MX1, an antiviral protein, interferon beta1, a cytokine promotor STAT1 (signal transducer and activator of transcription 1), and also increased protein expression levels of STAT1, phosphorylated STAT5 and MX1. Co-transfection of HUVECs with siMX1 and siMAGI1 impaired MAGI1 depletion-induced suppression of IAV infection. Furthermore, we found nuclear localization of interferon regulatory factor 3 (IRF3) in MAGI1 depleted cells, indicating that MAGI1 depletion elicits the interferon production and signaling. Taken together, we conclude that IAV infection and replication occurs in ECs in a MAGI1 expression dependent manner. Thus, MGAI1 depletion in ECs suppresses IAV replication, and this suppression is due to increased MX1 expression, which induces IRF3 activation and interferon production. MAGI1 can be a potential therapeutic target for influenza-induced CVD.

Bioactive molecule library screening may empirically identify effective combination therapies, but molecular mechanisms underlying favorable drug–drug interactions often remain unclear, precluding further rational design. In the absence of an accepted systems theory to interrogate synergistic responses, we introduce Omics-Based Interaction Framework (OBIF) to reveal molecular drivers of synergy through integration of statistical and biological interactions in synergistic biological responses. OBIF performs full factorial analysis of feature expression data from single versus dual exposures to identify molecular clusters that reveal synergy-mediating pathways, functions and regulators. As a practical demonstration, OBIF analyzed transcriptomic and proteomic data of a dyad of immunostimulatory molecules that induces synergistic protection against influenza A and revealed unanticipated NF-κB/AP-1 cooperation that is required for antiviral protection. To demonstrate generalizability, OBIF analyzed data from a diverse array of Omics platforms and experimental conditions, successfully identifying the molecular clusters driving their synergistic responses. Hence, unlike existing synergy quantification and prediction methods, OBIF is a phenotype-driven systems model that supports multiplatform interrogation of synergy mechanisms.

Background Community-acquired pneumonia (CAP) guidelines have improved the treatment and outcomes of patients with CAP, primarily by standardization of initial empirical therapy. But current society-published guidelines exclude immunocompromised patients. Research Question There is no consensus regarding the initial treatment of immunocompromised patients with suspected CAP. Study Design and Methods This consensus document was created by a multidisciplinary panel of 45 physicians with experience in the treatment of CAP in immunocompromised patients. The Delphi survey methodology was used to reach consensus. Results The panel focused on 21 questions addressing initial management strategies. The panel achieved consensus in defining the population, site of care, likely pathogens, microbiologic workup, general principles of empirical therapy, and empirical therapy for specific pathogens. Interpretation This document offers general suggestions for the initial treatment of the immunocompromised patient who arrives at the hospital with pneumonia.

Significance There is a pressing need for new antiinfluenza therapeutic agents. We show that a molecularly engineered banana lectin (carbohydrate-binding protein) has broad-spectrum activity against all influenza strains tested, including drug-resistant and currently circulating strains; is safe upon repeated administration in mice; and, moreover, is efficacious at treating lethal influenza infection via clinically pertinent routes of administration. We demonstrate that the lectin binds to the viral hemagglutinin glycoprotein and exerts its primary antiviral effect via inhibition of an early stage of the viral life cycle, viral membrane fusion to the host endosomal membrane. Our findings indicate that this engineered lectin, which has a mechanism of action quite distinct from the presently available agents, has potential as an antiinfluenza agent., There is a strong need for a new broad-spectrum antiinfluenza therapeutic, as vaccination and existing treatments are only moderately effective. We previously engineered a lectin, H84T banana lectin (H84T), to retain broad-spectrum activity against multiple influenza strains, including pandemic and avian, while largely eliminating the potentially harmful mitogenicity of the parent compound. The amino acid mutation at position 84 from histidine to threonine minimizes the mitogenicity of the wild-type lectin while maintaining antiinfluenza activity in vitro. We now report that in a lethal mouse model H84T is indeed nonmitogenic, and both early and delayed therapeutic administration of H84T intraperitoneally are highly protective, as is H84T administered subcutaneously. Mechanistically, attachment, which we anticipated to be inhibited by H84T, was only somewhat decreased by the lectin. Instead, H84T is internalized into the late endosomal/lysosomal compartment and inhibits virus–endosome fusion. These studies reveal that H84T is efficacious against influenza virus in vivo, and that the loss of mitogenicity seen previously in tissue culture is also seen in vivo, underscoring the potential utility of H84T as a broad-spectrum antiinfluenza agent.

Allergic asthma is a chronic inflammatory respiratory disease associated with eosinophilic infiltration, increased mucus production, airway hyperresponsiveness, and airway remodeling. Epidemiologic data reveal that the prevalence of allergic sensitization and associated diseases has increased in the twentieth century. This has been hypothesized to be partly due to reduced contact with microbial organisms (the hygiene hypothesis) in industrialized society. Airway epithelial cells, once considered a static physical barrier between the body and the external world, are now widely recognized as immunologically active cells that can initiate, maintain, and restrain inflammatory responses, such as those that mediate allergic disease. Airway epithelial cells can sense allergens via expression of myriad Toll-like receptors (TLRs) and other pattern-recognition receptors. We sought to determine whether the innate immune response stimulated by a combination of Pam2CSK4 (“Pam2”, TLR2/6 ligand) and a class C oligodeoxynucleotide ODN362 (“ODN”, TLR9 ligand), when delivered together by aerosol (“Pam2ODN”), can modulate the allergic immune response to allergens. Treatment with Pam2ODN 7 days before sensitization to House Dust Mite (HDM) extract resulted in a strong reduction in eosinophilic and lymphocytic inflammation. This Pam2ODN immunomodulatory effect was also seen using Ovalbumin (OVA) and A. oryzae (Ao) mouse models. The immunomodulatory effect was observed as much as 30 days before sensitization to HDM, but ineffective just 2 days after sensitization, suggesting that Pam2ODN immunomodulation lowers the allergic responsiveness of the lung, and reduces the likelihood of inappropriate sensitization to aeroallergens. Furthermore, Pam2 and ODN cooperated synergistically suggesting that this treatment is superior to any single agonist in the setting of allergen immunotherapy.

Besides providing an essential protective barrier, airway epithelial cells directly sense pathogens and respond defensively. This is a frontline component of the innate immune system with specificity for different pathogen classes. It occurs in the context of numerous interactions with leukocytes, but here we focus on intrinsic epithelial mechanisms. Type 1 immune responses are directed primarily at intracellular pathogens, particularly viruses. Prominent stimuli include microbial nucleic acids and interferons released from neighboring epithelial cells. Epithelial responses revolve around changes in the expression of interferon-sensitive genes (ISGs) that interfere with viral replication, as well as the further induction of interferons that signal in autocrine and paracrine manners. Type 2 immune responses are directed primarily at helminths and fungi. Prominent pathogen stimuli include proteases and chitin, and important responses include mucin hypersecretion and chitinase release. Type 3 immune responses are directed primarily at extracellular microbial pathogens, including bacteria and fungi, as well as viruses during their extracellular phase of infection. Prominent microbial stimuli include bacterial wall components, such as lipopeptides and endotoxin, as well as microbial nucleic acids. Key responses are the release of reactive oxygen species (ROS) and antimicrobial peptides (AMPs). For all three types of response, paracrine signaling to neighboring epithelial cells induces resistance to infection over a wide field. Often, the epithelial effector molecules themselves also have signaling properties, in addition to the release of inflammatory cytokines that boost local innate immunity. Together, these epithelial mechanisms provide a powerful first line of pathogen defense, recruit leukocytes, and instruct adaptive immune responses.

Allergic asthma is a chronic inflammatory respiratory disease associated with eosinophilic infiltration, increased mucus production, airway hyperresponsiveness (AHR), and airway remodeling. Epidemiologic data has revealed that the prevalence of allergic sensitization and associated diseases has increased in the twentieth century. This has been hypothesized to be partly due to reduced contact with microbial organisms (the hygiene hypothesis) in industrialized society. Airway epithelial cells, once considered a static physical barrier between the body and the external world, are now widely recognized as immunologically active cells that can initiate, maintain, and restrain inflammatory responses, such as those that mediate allergic disease. Airway epithelial cells can sense allergens via myriad expression of Toll-like receptors (TLRs) and other pattern-recognition receptors (PRRs). We sought to determine whether the innate immune response stimulated by a combination of Pam2CSK4 (“Pam2”, TLR2/6 ligand) and a class C oligodeoxynucleotide ODN362 (“ODN”, TLR9 ligand) when delivered together by aerosol (“Pam2ODN”), can modulate the allergic immune response to allergens. Treatment with Pam2ODN 7 days before sensitization to House Dust Mite (HDM) extract resulted in a strong reduction in eosinophilic and lymphocytic inflammation. This Pam2ODN immunomodulatory effect was also seen using Ovalbumin (OVA) and A. oryzae (Ao) mouse models. The immunomodulatory effect was observed as much as 30 days before sensitization to HDM, but ineffective just 2 days after sensitization, suggesting that Pam2ODN immunomodulation lowers the allergic responsiveness of airway epithelial cells. Furthermore, Pam2 and ODN cooperated synergistically suggesting that this treatment is superior to any single agonist in the setting of allergen immunotherapy.One Sentence SummaryA synergistic combination of Toll-like Receptor agonists, delivered directly into the lung mucosa, can attenuate allergic responsiveness of airway epithelial cells and prevent host sensitization to aeroallergens.What is already knownAllergic sensitization has increased in the 20th century due to reduced contact with microbial organisms in industrialized society (ie. hygiene hypothesis)We have previously identified a pharmacological means to stimulate innate immunity of lung epithelial cells.What this study addsActivation of innate immunity in lung epithelial cells attenuates the allergic responsiveness of mice.Synergistic cooperation of pattern recognition receptors induces stronger immunomodulatory responsesWhat is the clinical significanceAerosolized Toll-like Receptor agonists have been demonstrated as safe in human clinical trialsThis study provides proof-of-principle that aerosolized toll-like receptor agonists could have clinical efficacy in the setting of the allergen immunotherapy

Rationale: Prompt diagnosis of invasive fungal infections is important because of the associated morbidity and mortality; however, diagnosis is challenging because of the nonspecific symptoms and radiographic findings.Objectives: To conduct a systematic review and meta-analysis of studies that evaluated the diagnostic accuracy of serum and bronchoalveolar lavage (BAL) galactomannan (GM) and serum or BAL polymerase chain reaction (PCR) in patients with suspected invasive aspergillosis (IA), β-d-glucan in critically ill patients at risk for candidiasis or candidemia, and serology testing and antigen detection in patients with endemic mycoses (histoplasmosis, blastomycosis, and coccidioidomycosis).Methods: Studies were selected and appraised by pairs of reviewers. Bivariate random effects meta-analysis was used to generate pooled sensitivity, specificity, and diagnostic likelihood ratios.Results: Serum GM in patients with impaired immunity suspected of having IA had sensitivity of 0.71 (95% confidence interval [CI], 0.64-0.78) and specificity of 0.89 (95% CI, 0.84-0.92). A cutoff of 1 optical density index yielded optimal sensitivity and specificity. BAL GM in patients with impaired immunity suspected of having IA had sensitivity of 0.84 (95% CI, 0.73-0.91) and specificity of 0.88 (95% CI, 0.81-0.91). Serum or whole-blood PCR in immunocompromised patients with suspected IA had sensitivity of 0.81 (95% CI, 0.73-0.86) and specificity of 0.79 (95% CI, 0.68-0.86). BAL PCR in patients at high risk for IA had high sensitivity of 0.90 (95% CI, 0.77-0.96) and specificity of 0.96 (95% CI, 0.93-0.98) for diagnosing IA. β-d-glucan assay in patients in the intensive care unit at risk for invasive candidiasis or candidemia had sensitivity of 0.81 (95% CI, 0.74-0.86) and specificity of 0.60 (95% CI, 0.49-0.71). Data on diagnostic accuracy of antigen detection and serology testing for endemic mycoses were limited and heterogeneous (varied according to test, patient immunity, and suspected endemic disease).Conclusions: The diagnosis of invasive fungal infections remains a challenge. Various serum and BAL markers can aid in diagnosis. This evidence supports the development of clinical practice recommendations by the American Thoracic Society.

RATIONALE: While the relationship between inflammation and depression is well-established, the molecular mechanisms mediating this relationship remain unclear. RNA-sequencing analysis comparing brains of vehicle- and lipopolysaccharide-treated mice revealed LCN2 among the most dysregulated genes. As LCN2 is known to be an important regulator of the immune response to bacterial infection, we investigated its role in the behavioral response to lipopolysaccharide. OBJECTIVE: To explore the role of LCN2 in modulating behavior following lipopolysaccharide administration using wild type (WT) and lcn2(−/−) mice. METHODS: Using a within-subjects design, mice were treated with 0.33 mg/kg liposaccharide (LPS) and vehicle. Primary outcome measures included: body weight, food consumption, voluntary wheel running, sucrose preference, and the tail suspension test. To evaluate the inflammatory response, one week later mice were re-administered either vehicle or LPS and terminated at 6 h. RESULTS: While lcn2(−/−) mice had increased baseline food consumption and body weight, they showed a pattern of reduced food consumption and weight loss following LPS treatment similar to WT mice. WT and lcn2(−/−) mice both recovered voluntary activity on the fourth day following LPS. LPS induced equivalent reductions in sucrose preference and TST immobility in the WT and lcn2(−/−) mice. Finally, there were no significant effects of genotype on inflammatory markers. CONCLUSIONS: Our data demonstrate that lcn2 is dispensable for sterile inflammation-induced sickness and depression-like behavior. Specifically, lcn2(−/−) mice displayed sickness and immobility in the tail suspension test comparable to that of WT mice both in terms of intensity and duration.

Objective: Viral pneumonias cause significant morbidity and mortality worldwide. The emergence of novel SARSCoV- 2 emphasizes the need for novel antiviral therapies. Dexamethasone (DXM) is one therapy that has recently been reported to confer benefit in severe SARS-CoV-2 infection. Our lab has recently reported that CD8+ T cells were associated with fatal immunopathology causing mortality in a mouse model of severe Sendai paramyxovirus (SeV) pneumonia, and this fatal immunopathology could be prevented either by eliciting a robust, early antiviral response via inhalational treatment with Toll-like receptor agonists (Pam2-ODN) or by depletion of CD8+ T cells during late stage SeV pneumonia. Given the lympholytic effects of DXM, we tested our hypothesis that the reported survival advantage of DXM in severe viral pneumonia derives from CD8+ T cell- mediated immunopathology. Methods: Mice were intrapharyngeally infected with SeV with or without Pam2-ODN pretreatment, then observed for 14 days. Some mice were intraperitoneally injected with DXM (5mg/kg) every day starting day 0 or day 8 after infection. CD8+ T cells were assessed on day 10 after infection by flow cytometry of digested mouse lungs. Results: Treatment with DXM starting on day 8 enhanced mouse survival of SeV pneumonia, whereas mice treated with DXM from day -1 onward demonstrated increased susceptibility to SeV pneumonia. Mice treated with CD8+ T cell depleting antibody on day 8 displayed 100% survival. DXM treated mice displayed reduced CD8+ T cells in comparison to PBS treated SeV challenged mice, supporting our hypothesis. Consistent with our recent report, mice aerosolized with Pam2-ODN displayed 100% survival of SeV pneumonia with reduced CD8+ T cell lung influx on day 10. Conclusion: These data suggest that the survival benefit of DXM in severe viral pneumonia results from reduced CD8+ T cell-mediated immunopathology. Improved outcomes appear likely to be achieved by either use of broad immunosuppressive agents such as DXM or a targeted approach to deplete CD8+ T cells during late-stage pneumonia such as COVID19. These data also provide a preclinical model to test other immunosuppressive agents and optimize timing and dosing of such agents.

Background: This document provides evidence-based clinical practice guidelines on the diagnostic utility of nucleic acid-based testing of respiratory samples for viral pathogens other than influenza in adults with suspected community-acquired pneumonia (CAP).Methods: A multidisciplinary panel developed a Population-Intervention-Comparison-Outcome question, conducted a pragmatic systematic review, and applied Grading of Recommendations, Assessment, Development, and Evaluation methodology for clinical recommendations.Results: The panel evaluated the literature to develop recommendations regarding whether routine diagnostics should include nucleic acid-based testing of respiratory samples for viral pathogens other than influenza in suspected CAP. The evidence addressing this topic was generally adjudicated to be of very low quality because of risk of bias and imprecision. Furthermore, there was little direct evidence supporting a role for routine nucleic acid-based testing of respiratory samples in improving critical outcomes such as overall survival or antibiotic use patterns. However, on the basis of direct and indirect evidence, recommendations were made for both outpatient and hospitalized patients with suspected CAP. Testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was not addressed in the literature at the time of the evidence review.Conclusions: The panel formulated and provided their rationale for recommendations on nucleic acid-based diagnostics for viral pathogens other than influenza for patients with suspected CAP.

Background: Pneumonias exert tremendous worldwide morbidity, especially among immunocompromised populations. Our laboratory has identified an inhaled therapeutic comprised of Toll-like receptor (TLR) 2/6 and TLR9 agonists that protects mice against a broad array of respiratory pathogens. This protection is associated with the generation of an antimicrobial environment in the lungs and requires induction of epithelial reactive oxygen species of both dual oxidase and mitochondrial sources. Objective: To discern how the treatment induces generation of mitochondrial reactive oxygen species (mtROS). Results: Inducible mtROS generation was driven by epithelial exposure to a class C CpG oligodeoxynucleotide (ODN M362), a reported TLR9 ligand. However, ODN M362-induced mtROS generation was not dependent on TLR9 signaling, but required that the oligodeoxynucleotide include phosphorothiorate linkages, rather than the phosphodiester linkages common in the DNA of most species. Phosphorothiorate ODN directly interacted with mitochondrial permeability transition pores, altering the ATP:ADP ratio in both cytosol and mitochondria, activating AMPK and ACC pathways and increasing beta-oxidation. This led to enhancement of electron transport chain complex II activity and reduction of complex III activity, causing increased electron leakage that resulted in superoxide (O2- ·) production. The resultant mtROS both exerted directly microbicidal effects and stabilized Hif1α to support antimicrobial peptide production. Conclusions: These data identify novel means to manipulate mtROS and may provide an opportunity to protect vulnerable patients against pneumonia.

Viral pneumonias remain global health threats, as exemplified in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, requiring novel treatment strategies both early and late in the disease process. We have reported that mice treated before or soon after infection with a combination of inhaled Toll-like receptor (TLR) 2/6 and 9 agonists (Pam2-ODN) are broadly protected against microbial pathogens including respiratory viruses, but the mechanisms remain incompletely understood. The objective of this study was to validate strategies for immune modulation in a preclinical model of viral pneumonia and determine their mechanisms. Mice were challenged with the Sendai paramyxovirus in the presence or absence of Pam2-ODN treatment. Virus burden and host immune responses were assessed to elucidate Pam2-ODN mechanisms of action and to identify additional opportunities for therapeutic intervention. Enhanced survival of Sendai virus pneumonia with Pam2-ODN treatment was associated with reductions in lung virus burden and with virus inactivation before internalization. We noted that mortality in sham-treated mice corresponded with CD8+ T-cell lung inflammation on days 11-12 after virus challenge, after the viral burden had declined. Pam2-ODN blocked this injurious inflammation by minimizing virus burden. As an alternative intervention, depleting CD8+ T cells 8 days after viral challenge also decreased mortality. Stimulation of local innate immunity within the lungs by TLR agonists early in disease or suppression of adaptive immunity by systemic CD8+ T-cell depletion late in disease improves outcomes of viral pneumonia in mice. These data reveal opportunities for targeted immunomodulation to protect susceptible human subjects.

Intensive care units (ICUs) are an appropriate focus of antibiotic stewardship program efforts because a large proportion of any hospital's use of parenteral antibiotics, especially broad-spectrum, occurs in the ICU. Given the importance of antibiotic stewardship for critically ill patients and the importance of critical care practitioners as the front line for antibiotic stewardship, a workshop was convened to specifically address barriers to antibiotic stewardship in the ICU and discuss tactics to overcome these. The working definition of antibiotic stewardship is "the right drug at the right time and the right dose for the right bug for the right duration." A major emphasis was that antibiotic stewardship should be a core competency of critical care clinicians. Fear of pathogens that are not covered by empirical antibiotics is a major driver of excessively broad-spectrum therapy in critically ill patients. Better diagnostics and outcome data can address this fear and expand efforts to narrow or shorten therapy. Greater awareness of the substantial adverse effects of antibiotics should be emphasized and is an important counterargument to broad-spectrum therapy in individual low-risk patients. Optimal antibiotic stewardship should not focus solely on reducing antibiotic use or ensuring compliance with guidelines. Instead, it should enhance care both for individual patients (by improving and individualizing their choice of antibiotic) and for the ICU population as a whole. Opportunities for antibiotic stewardship in common ICU infections, including community- and hospital-acquired pneumonia and sepsis, are discussed. Intensivists can partner with antibiotic stewardship programs to address barriers and improve patient care.

Bioactive molecule library screening strategies may empirically identify effective combination therapies. However, without a systems theory to interrogate synergistic responses, the molecular mechanisms underlying favorable drug-drug interactions remain unclear, precluding rational design of combination therapies. Here, we introduce Omics-Based Interaction Framework (OBIF) to reveal molecular drivers of synergy through integration of statistical and biological interactions in supra-additive biological responses. OBIF performs full factorial analysis of feature expression data from single vs. dual factor exposures to identify molecular clusters that reveal synergy-mediating pathways, functions and regulators. As a practical demonstration, OBIF analyzed a therapeutic dyad of immunostimulatory small molecules that induces synergistic protection against influenza A pneumonia. OBIF analysis of transcriptomic and proteomic data identified biologically relevant, unanticipated cooperation between RelA and cJun that we subsequently confirmed to be required for the synergistic antiviral protection. To demonstrate generalizability, OBIF was applied to data from a diverse array of Omics platforms and experimental conditions, successfully identifying the molecular clusters driving their synergistic responses. Hence, OBIF is a phenotype-driven systems model that supports multiplatform exploration of synergy mechanisms.

Viral pneumonia remains a global health threat requiring novel treatment strategies, as strikingly exemplified in the SARS-CoV-2 pandemic of 2019-2020. We have reported that mice treated with a combination of inhaled Toll-like receptor (TLR) 2/6 and TLR 9 agonists (Pam2-ODN) to stimulate innate immunity are broadly protected against respiratory pathogens, but the mechanisms underlying this protection remain incompletely elucidated. Here, we show in a lethal paramyxovirus model that Pam2-ODN-enhanced survival is associated with robust virus inactivation by reactive oxygen species (ROS), which occurs prior to internalization by lung epithelial cells. However, we also found that mortality in sham-treated mice temporally corresponded with CD8+ T cell-enriched lung inflammation that peaks on days 11-12 after viral challenge, when the viral burden has waned to a scarcely detectable level. Pam2-ODN treatment blocked this injurious inflammation by reducing the viral burden, and alternatively, depleting CD8+ T cells 8 days after viral challenge also decreased mortality. These findings reveal opportunities for targeted immunomodulation to protect susceptible individuals against the morbidity and mortality of respiratory viral infections.

Viral pneumonias remain a global health threat necessitating novel strategies to prevent and treat these lower respiratory tract infections. We have reported that mice treated with a combination of inhaled Toll-like receptor (TLR) 2/6 and TLR 9 agonists (Pam2-ODN) are broadly protected against respiratory pathogens. Although a single inhalation of Pam-ODN prevents acute morbidity and chronic complications associated with viral pneumonias, the mechanisms underlying this protection remain incompletely elucidated. Here, we show in a lethal paramyxovirus model that Pam2-ODN-enhanced survival is associated with robust virus inactivation that occurs prior to internalization by lung epithelial cells. However, it was also noted that viral mortality in sham-treated mice temporally corresponded with CD8+ T cell-enriched lung inflammation that peaks after the viral burden wanes. Pam2-ODN treatment also blocked this injurious inflammation, but the attenuation of lymphocytic inflammation and the reduction in virus burden were both lost when inducible reactive oxygen species generation was inhibited. Depleting CD8+ T cells before or after viral challenge underscored the balanced roles of CD8+ T cells in antiviral immunity and fatal immunopathology, but did not obviate the Pam2-ODN antiviral protection. These findings identify multifunctional inducible antiviral mechanisms and may reveal means to protect susceptible individuals against respiratory infections.

Somatic KRAS mutations are the most common oncogenic variants in lung cancer and are associated with poor prognosis. Using a Kras-induced lung cancer mouse model, CC-LR, we previously showed a role for inflammation in lung tumorigenesis through activation of the NF-κB pathway, along with induction of interleukin 6 (IL6) and an IL17-producing CD4+ T-helper cell response. IL22 is an effector molecule secreted by CD4+ and γδ T cells that we previously found to be expressed in CC-LR mice. IL22 mostly signals through the STAT3 pathway and is thought to act exclusively on nonhematopoietic cells with basal IL22 receptor (IL22R) expression on epithelial cells. Here, we found that higher expression of IL22R1 in patients with KRAS-mutant lung adenocarcinoma was an independent indicator of poor recurrence-free survival. We then showed that genetic ablation of Il22 in CC-LR mice (CC-LR/IL22KO mice) caused a significant reduction in tumor number and size. This was accompanied by significantly lower tumor cell proliferation, angiogenesis, and STAT3 activation. Il22 ablation was also associated with significant reduction in lung-infiltrating inflammatory cells and expression of protumor inflammatory cytokines. Conversely, this was accompanied with increased antitumor Th1 and cytotoxic CD8+ T-cell responses, while suppressing the protumor immunosuppressive T regulatory cell response. In CC-LR/IL22KO mice, we found significantly reduced expression of core stemness genes and the number of prototypical SPC+CCSP+ stem cells. Thus, we conclude that IL22 promotes Kras-mutant lung tumorigenesis by driving a protumor inflammatory microenvironment with proliferative, angiogenic, and stemness contextual cues in epithelial/tumor cells. Cancer Immunol Res; 6(7); 788–97. ©2018 AACR.

Pneumonia is a leading global cause of morbidity and mortality, particularly amongst adults aged >70 years and children. Annual deaths due to pneumonia in these groups was estimated at more than one million and 672 000 worldwide for both groups, respectively, in 2019 [1]. The importance of pneumonia is highlighted by impact of the current coronavirus disease 2019 (COVID-19) pandemic on vulnerable populations. Yet, despite the high impact of pneumonia worldwide, diagnosing pneumonia, especially in children in low- and middle-income countries, remains a big challenge. Frequent clinical signs of pneumonia (cough and difficult or rapid breathing) are non-specific and can overlap with other prevalent diseases in these settings, such as malaria. Equally important, data provided by the World Health Organization (WHO) revealed that 40% of children with pneumonia symptoms in the 40 countries reporting 90% of child pneumonia deaths never receive medical care for their pneumonia [2]. Furthermore, overdiagnosis of bacterial pneumonia and unnecessary administration of antibiotics poses an extra challenge, particularly in countries with limited resources for diagnostic procedures.

Bacterial pneumonias exact unacceptable morbidity on patients with cancer. Although the risk is often most pronounced among patients with treatment-induced cytopenias, the numerous contributors to life-threatening pneumonias in cancer populations range from derangements of lung architecture and swallow function to complex immune defects associated with cytotoxic therapies and graft-versus-host disease. These structural and immunologic abnormalities often make the diagnosis of pneumonia challenging in patients with cancer and impact the composition and duration of therapy. This article addresses host factors that contribute to pneumonia susceptibility, summarizes diagnostic recommendations, and reviews current guidelines for management of bacterial pneumonia in patients with cancer.

Viral pneumonias in patients with hematologic malignancies and recipients of hematopoietic stem cell transplantation cause significant morbidity and mortality. Advances in diagnostic techniques have enabled rapid identification of respiratory viral pathogens from upper and lower respiratory tract samples. Lymphopenia, myeloablative and T-cell depleting chemotherapy, graft-versus-host disease, and other factors increase the risk of developing life-threatening viral pneumonia. Chest imaging is often nonspecific but may aid in diagnoses. Bronchoscopy with bronchoalveolar lavage is recommended in those at high risk for viral pneumonia who have new infiltrates on chest imaging.

Background and purpose Respiratory viral infections play central roles in the initiation, exacerbation and progression of asthma in humans. An acute paramyxoviral infection in mice can cause a chronic lung disease that resembles human asthma. We sought to determine whether reduction of Sendai virus lung burden in mice by stimulating innate immunity with aerosolized Toll-like receptor (TLR) agonists could attenuate the severity of chronic asthma-like lung disease. Experimental approach Mice were treated by aerosol with 1-μM oligodeoxynucleotide (ODN) M362, an agonist of the TLR9 homodimer, and 4-μM Pam2CSK4 (Pam2), an agonist of the TLR2/6 heterodimer, within a few days before or after Sendai virus challenge. Key results Treatment with ODN/Pam2 caused ~75% reduction in lung Sendai virus burden 5 days after challenge. The reduction in acute lung virus burden was associated with marked reductions 49 days after viral challenge in eosinophilic and lymphocytic lung inflammation, airway mucous metaplasia, lumenal mucus occlusion and hyperresponsiveness to methacholine. Mechanistically, ODN/Pam2 treatment attenuated the chronic asthma phenotype by suppressing IL-33 production by type 2 pneumocytes, both by reducing the severity of acute infection and by down-regulating Type 2 (allergic) inflammation. Conclusion and implications These data suggest that treatment of susceptible human hosts with aerosolized ODN and Pam2 at the time of a respiratory viral infection might attenuate the severity of the acute infection and reduce initiation, exacerbation and progression of asthma.

Background: Fungal infections are of increasing incidence and importance in immunocompromised and immunocompetent patients. Timely diagnosis relies on appropriate use of laboratory testing in susceptible patients. Methods: The relevant literature related to diagnosis of invasive pulmonary aspergillosis, invasive candidiasis, and the common endemic mycoses was systematically reviewed. Meta-analysis was performed when appropriate. Recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation approach. Results: This guideline includes specific recommendations on the use of galactomannan testing in serum and BAL and for the diagnosis of invasive pulmonary aspergillosis, the role of PCR in the diagnosis of invasive pulmonary aspergillosis, the role of β-d-glucan assays in the diagnosis of invasive candidiasis, and the application of serology and antigen testing in the diagnosis of the endemic mycoses. Conclusions: Rapid, accurate diagnosis of fungal infections relies on appropriate application of laboratory testing, including antigen testing, serological testing, and PCR-based assays.