Review of recent lung biomarkers of potential harm/effect for tobacco research

Biomarkers of potential harm (BoPH) are indicators of biological perturbations which may contribute to the pathophysiology of disease. In this review, we critically assessed the published data on lung-related BoPH in human lung disease for potential use in evaluating the effects of tobacco and nicotine products. A Scopus literature search was conducted on lung disease biomarkers used in a clinical setting over the last 10 years. We identified 1171 papers which were further screened using commercial software (Sciome SWIFT-Active Screener) giving 68 publications that met our inclusion criteria (data on the association of the biomarker with cigarette smoking, the impact of smoking cessation on the biomarker, and differences between smokers and non-smokers), the majority of which investigated chronic obstructive pulmonary disease. Several physiological and biochemical measures were identified that are potentially relevant for evaluating the impact of tobacco products on lung health. Promising new candidates included blood biomarkers, such as surfactant protein D (SP-D), soluble receptor for advanced glycation end products (sRAGE), skin autofluorescence (SAF), and imaging techniques. These biomarkers may provide insights into lung disease development and progression; however, all require further research and validation to confirm their role in the context of tobacco and nicotine exposure, their time course of development and ability to measure or predict disease progression.

Viral Evasion of Innate Immune Defense: The Case of Resistance of Pandemic H1N1 Influenza A Virus to Human Mannose-Binding Proteins

Mannose-binding lectins effectively inhibit most seasonal strains of influenza A virus and contribute to the innate host defense vs. these viruses. In contrast, pandemic IAV strains are largely resistant to these lectins, likely contributing to increased spread and worse outcomes. In this paper, we evaluated the inhibition of IAV by mannose-binding lectins of human, bacterial, and fungal origin to understand and possibly increase activity vs. the pandemic IAV. A modified version of the human surfactant protein D (SP-D) neck and carbohydrate recognition domain (NCRD) with combinatorial substitutions at the 325 and 343 positions, previously shown to inhibit pandemic H3N2 IAV in vitro and in vivo, and to inhibit pandemic H1N1 in vitro, failed to protect mice from pandemic H1N1 in vivo in the current study. We attempted a variety of maneuvers to improve the activity of the mutant NCRDs vs. the 2009 pandemic H1N1, including the formation of full-length SP-D molecules containing the mutant NCRD, cross-linking of NCRDs through the use of antibodies, combining SP-D or NCRDs with alpha-2-macroglobulin, and introducing an additional mutation to the double mutant NCRD. None of these substantially increased the antiviral activity for the pandemic H1N1. We also tested the activity of bacterial and algal mannose-binding lectins, cyanovirin, and griffithsin, against IAV. These had strong activity against seasonal IAV, which was largely retained against pandemic H1N1. We propose mechanisms to account for differences in activity of SP-D constructs against pandemic H3N2 and H1N1, and for differences in activity of cyanovirin vs. SP-D constructs.

Age-Related Expression of IFN-λ1 Versus IFN-I and Beta-Defensins in the Nasopharynx of SARS-CoV-2-Infected Individuals

SARS-CoV-2 coronavirus infection induces heterogeneous symptoms, ranging from asymptomatic to lethal forms. Severe forms usually occur in the elderly and/or individuals with comorbidities. Children generally remain asymptomatic to primary infection, suggesting that they may have an effective local innate immune response. IFN-I and -III have non-redundant protective roles against SARS-CoV-2, although sometimes damaging the host. The expression and role of anti-viral peptides during SARS-CoV-2 infection have thus far been little studied. We aimed to identify the innate immune molecules present at the SARS-CoV-2 entry point. We analyzed the mRNA levels of type I (IFN-α and -β) and type III (IFN-λ1-3) interferons and selected antiviral peptides (i.e., β-defensins 1-3, α-defensins [HNP1-3, HD5] pentraxin-3, surfactant protein D, the cathelicidin LL-37 and interleukin-26) in nasopharyngeal swabs from 226 individuals of various ages, either infected with SARS-CoV-2 (symptomatic or asymptomatic) or negative for the virus. We observed that infection induced selective upregulation of IFN-λ1 expression in pediatric subjects (≤15 years), whereas IFN-α, IFN-β, IFN-λ2/λ3, and β-defensin 1-3 expression was unaffected. Conversely, infection triggered upregulation of IFN-α, IFN-β, IFN-λ2/λ3, and β-defensin 1-3 mRNA expression in adults (15-65 years) and the elderly (≥ 65 years), but without modulation of IFN-λ1. The expression of these innate molecules was not associated with gender or symptoms. Expression of the interferon-stimulated genes IFITM1 and IFITM3 was upregulated in SARS-CoV-2-positive subjects and reached similar levels in the three age groups. Finally, age-related differences in nasopharyngeal innate immunity were also observed in SARS-CoV-2-negative subjects. This study shows that the expression patterns of IFN-I/-III and certain anti-viral molecules in the nasopharyngeal mucosa of SARS-CoV-2-infected subjects differ with age and suggests that susceptibility to SARS-CoV-2 may be related to intrinsic differences in the nature of mucosal anti-viral innate immunity.

The Role of Surface in the Pathogenesis and Treatment of COVID-19

Recently, an inverse relationship between incidence of COVID-19 and seasonal aerosolization of mold spores was demonstrated. Analyses of that relationship suggested mold spores compete with SARS-CoV-2 virions for a receptor on the pulmonary epithelial surface. By inference, the operative receptor was proposed to be Toll-like receptor 4, with surface-localized virions being responsible for symptomatology. In this report, the pathogenesis of COVID-19 is further developed, with a focus on a role for surfactant protein D in the process. This developed proposal provides both mechanistic understanding and suggested treatments of COVID-19.