Aspirin, with its active compound acetylsalicylic acid (ASA), shows antiviral activity against rhino- and influenza viruses at high concentrations. We sought to investigate whether ASA and its metabolite salicylic acid (SA) inhibit SARS-CoV-2 since it might use similar pathways to influenza viruses. The compound-treated cells were infected with SARS-CoV-2. Viral replication was analysed by RTqPCR. The compounds suppressed SARS-CoV-2 replication in cell culture cells and a patient-near replication system using human precision-cut lung slices by two orders of magnitude. While the compounds did not interfere with viral entry, it led to lower viral RNA expression after 24 h, indicating that post-entry pathways were inhibited by the compounds.

Human rhinovirus (RV) is a major risk factor for chronic obstructive pulmonary disease (COPD) and asthma exacerbations. The exploration of RV pathogenesis has been hampered by a lack of disease-relevant model systems. We performed a detailed characterization of host responses to RV infection in human lung tissue ex vivo and investigated whether these responses are disease relevant for patients with COPD and asthma. In addition, impact of the viral replication inhibitor rupintrivir was evaluated. Human precision-cut lung slices (PCLS) were infected with RV1B with or without rupintrivir. At Days 1 and 3 after infection, RV tissue localization, tissue viability, and viral load were determined. To characterize host responses to infection, mediator and whole genome analyses were performed. RV successfully replicated in PCLS airway epithelial cells and induced both antiviral and proinflammatory cytokines such as IFNα2a, CXCL10, CXCL11, IFN-γ, TNFα, and CCL5. Genomic analyses revealed that RV not only induced antiviral immune responses but also triggered changes in epithelial cell–associated pathways. Strikingly, the RV response in PCLS was reflective of gene expression changes described in patients with COPD and asthma. Although RV-induced host immune responses were abrogated by rupintrivir, RV-triggered epithelial processes were largely refractory to antiviral treatment. Detailed analysis of RV-infected human PCLS and comparison with gene signatures of patients with COPD and asthma revealed that the human RV PCLS model represents disease-relevant biological mechanisms that can be partially inhibited by a well-known antiviral compound and provide an outstanding opportunity to evaluate novel therapeutics.

Rhinovirus (RV) is the predominant virus causing respiratory tract infections. Bronchobini^® is a low dose multi component, multi target preparation used to treat inflammatory respiratory diseases such as the common cold, described to ease severity of symptoms such as cough and viscous mucus production. The aim of the study was to assess the efficacy of Bronchobini^® in RV infection and to elucidate its mode of action. Therefore, Bronchobini^®’s ingredients (BRO) were assessed in an ex vivo model of RV infection using mouse precision-cut lung slices, an organotypic tissue capable to reflect the host immune response to RV infection. Cytokine profiles were assessed using enzyme-linked immunosorbent assay (ELISA) and mesoscale discovery (MSD). Gene expression analysis was performed using Affymetrix microarrays and ingenuity pathway analysis. BRO treatment resulted in the significant suppression of RV-induced antiviral and pro-inflammatory cytokine release. Transcriptome analysis revealed a multifactorial mode of action of BRO, with a strong inhibition of the RV-induced pro-inflammatory and antiviral host response mediated by nuclear factor kappa B (NFkB) and interferon signaling pathways. Interestingly, this was due to priming of these pathways in the absence of virus. Overall, BRO exerted its beneficial anti-inflammatory effect by priming the antiviral host response resulting in a reduced inflammatory response to RV infection, thereby balancing an otherwise excessive inflammatory response.

Respiratory viruses such as respiratory syncytial virus (RSV) or rhinovirus are one of the major causes for respiratory tract infections causing common cold disease. Respiratory viral infections range from mild symptoms in adults to serious illness especially in the very young or elderly as well as patients suffering from lung diseases or being immunocompromised due to other reasons. Engystol (EGY-2) is a multicomponent, multitarget preparation consisting of Vincetoxicum hirundinaria and Sulfur in various dilutions. The study objective was to test the effect of EGY-2 on the innate immune response during the early onset of respiratory viral infection in vivo as exemplified in a mouse model of RSV-induced respiratory inflammation. Naïve BALB/c mice were infected with 1x10⁶ infectious units RSV A2 intranasally to cause a mild respiratory infection. EGY-2 was administered daily per oral gavage starting seven days prior to RSV infection at doses of 0.4 to 5.1 tablets/kg. Control groups received placebo treatment. Animals were sacrificed 1 to 3 days post infection (p.i.) to analyse the infection and induced immune response in the lung. Viral load in bronchoalveolar lavage fluid (BALF) and lung homogenate was determined by TCID₅₀ assay as well as immunofluorescence staining of BALF cells using anti-RSV antibody and microscopic analysis. The RSV induced immune response was assessed by evaluation of BALF differential cell count, BALF cytokine secretion and analysis of the phagocytic capacity of alveolar macrophages. EGY-2 significantly reduced the RSV induced neutrophil and early lymphocyte influx on day 1 p.i. in BALF. EGY-2 treatment significantly diminished the RSV induced secretion of pro-inflammatory cytokines such as IFN-γ, IL-1β, IL-6, KC and TNF-α at day 1. EGY-2 treatment was not protective for RSV infection per se, as no alteration in the viral load in lung and BALF was detected. Enhanced numbers of phagocytic-active macrophages were observed in EGY-2 treated animals on day 1 and this macrophage population showed strongly enhanced phagocytic activity on day 1 and day 3. The data suggest a beneficial immunomodulatory effect of EGY-2 during early onset of respiratory viral infection in vivo, mediated by stimulation of macrophage phagocytosis, resulting in a reduced innate inflammatory response in terms of neutrophil and early lymphocyte infiltration as well as reduced inflammatory cytokine secretion.

Antibiotic resistance is a significant healthcare concern. Therefore, identifying target molecules that can serve as antibiotic substitutes is crucial. Among the promising candidates are antimicrobial peptides (AMPs). AMPs are defense mechanisms of the innate immune system which exist in almost all living organisms. Research on the AMPs of some amphibians has shown that, in addition to their antimicrobial effectiveness, AMPs also exhibit anti-inflammatory and anti-carcinogenic properties. In this study, we identify and characterize AMPs deriving from the skin mucus of the axolotl (Ambystoma mexicanum). Upon activity spectrum evaluation of the AMPs, we synthesized and ranked 22 AMPs according to antimicrobial efficacy by means of a prediction tool. To assess the AMPs’ potential as antibacterial and anticarcinogenic compounds, we performed a minimum inhibitory concentration (MIC) assay for efficacy against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA), and an apoptosis assay on T-47D mammary carcinoma cells. We identified four AMPs that showed significant inhibition of MRSA, of which three also demonstrated anticarcinogenic activity. Gene expression analysis was performed on AMP-stimulated carcinoma cells using a breast cancer-specific RT-PCR array. In cells stimulated with the AMPs, gene expression analysis showed upregulation of tumor suppressor genes and downregulation of oncogenes. Overall, our work demonstrates the antimicrobial and anticarcinogenic activity of axolotl-derived AMPs. The results of this work serve as a basis to further investigate the mode of action and potential use of axolotl AMPs as therapeutic anticancer or antibiotic agents.