Effect of High Glucose on MUC5B expression in Human Airway Epithelial Cells

Objectives Excessive production of mucus results in plugging of the airway tract, which can increase morbidity and mortality in affected patients. In patients with diabetes, inflammatory airway disease appears with more frequent relapse and longer duration of symptoms. However, the effects of high glucose (HG) on the secretion of mucin in inflammatory respiratory diseases are not clear. Therefore, this study was conducted in order to investigate the effect and the brief signaling pathway of HG on MUC5B expression in human airway epithelial cells. Methods The effect and signaling pathway of HG on MUC5B expression were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with specific inhibitors and small interfering RNA. Results HG increased MUC5B expression and epidermal growth factor receptor (EGFR) expression, and activated the phosphorylation of EGFR and p38 mitogen-activated protein kinase (MAPK). Pretreatment with EGFR inhibitor significantly attenuated the HG-induced phosphorylation of p38 MAPK, and pretreatments with p38 inhibitor or EGFR inhibitor significantly attenuated HG-induced MUC5B expression. In addition, knockdown of p38 MAPK by p38 MAPK siRNA significantly blocked HG-induced MUC5B expression. Conclusion These findings suggest that HG induces MUC5B expression via the sequential activations of the EGFR/p38 MAPK signaling pathway in human airway epithelial cells

Options and Obstacles for Designing a Universal Influenza Vaccine

Since the discovery of antibodies specific to a highly conserved stalk region of the influenza virus hemagglutinin (HA), eliciting such antibodies has been considered the key to developing a universal influenza vaccine that confers broad-spectrum protection against various influenza subtypes. To achieve this goal, a prime/boost immunization strategy has been heralded to redirect host immune responses from the variable globular head domain to the conserved stalk domain of HA. While this approach has been successful in eliciting cross-reactive antibodies against the HA stalk domain, protective efficacy remains relatively poor due to the low immunogenicity of the domain, and the cross-reactivity was only within the same group, rather than among different groups. Additionally, concerns are raised on the possibility of vaccine-associated enhancement of viral infection and whether multiple boost immunization protocols would be considered practical from a clinical standpoint. Live attenuated vaccine hitherto remains unexplored, but is expected to serve as an alternative approach, considering its superior cross-reactivity. This review summarizes recent advancements in the HA stalk-based universal influenza vaccines, discusses the pros and cons of these approaches with respect to the potentially beneficial and harmful effects of neutralizing and non-neutralizing antibodies, and suggests future guidelines towards the design of a truly protective universal influenza vaccine

Evaluation of green tea extract as a safe personal hygiene against viral infections

Abstract Background Viral infections often pose tremendous public health concerns as well as economic burdens. Despite the availability of vaccines or antiviral drugs, personal hygiene is considered as effective means as the first-hand measure against viral infections. The green tea catechins, in particular, epigallocatechin-3-gallate (EGCG), are known to exert potent antiviral activity. In this study, we evaluated the green tea extract as a safe personal hygiene against viral infections. Results Using the influenza virus A/Puerto Rico/8/34 (H1N1) as a model, we examined the duration of the viral inactivating activity of green tea extract (GTE) under prolonged storage at various temperature conditions. Even after the storage for 56 days at different temperatures, 0.1% GTE completely inactivated 106 PFU of the virus (6 log10 reduction), and 0.01% and 0.05% GTE resulted in 2 log10 reduction of the viral titers. When supplemented with 2% citric acid, 0.1% sodium benzoate, and 0.2% ascorbic acid as anti-oxidant, the inactivating activity of GTE was temporarily compromised during earlier times of storage. However, the antiviral activity of the GTE was steadily recovered up to similar levels with those of the same concentrations of GTE without the supplements, effectively prolonging the duration of the virucidal function over extended period. Cryo-EM and DLS analyses showed a slight increase in the overall size of virus particles by GTE treatment. The results suggest that the virucidal activity of GTE is mediated by oxidative crosslinking of catechins to the viral proteins and the change of physical properties of viral membranes. Conclusions The durability of antiviral effects of GTE was examined as solution type and powder types over extended periods at various temperature conditions using human influenza A/H1N1 virus. GTE with supplements demonstrated potent viral inactivating activity, resulting in greater than 4 log10 reduction of viral titers even after storage for up to two months at a wide range of temperatures. These data suggest that GTE-based antiviral agents could be formulated as a safe and environmentally friendly personal hygiene against viral infections

Non-specific Effect of Vaccines: Immediate Protection against Respiratory Syncytial Virus Infection by a Live Attenuated Influenza Vaccine

The non-specific effects (NSEs) of vaccines have been discussed for their potential long-term beneficial effects beyond direct protection against a specific pathogen. Cold-adapted, live attenuated influenza vaccine (CAIV) induces local innate immune responses that provide a broad range of antiviral immunity. Herein, we examined whether X-31ca, a donor virus for CAIVs, provides non-specific cross-protection against respiratory syncytial virus (RSV). The degree of RSV replication was significantly reduced when X-31ca was administered before RSV infection without any RSV-specific antibody responses. The vaccination induced an immediate release of cytokines and infiltration of leukocytes into the respiratory tract, moderating the immune perturbation caused by RSV infection. The potency of protection against RSV challenge was significantly reduced in TLR3-/- TLR7-/- mice, confirming that the TLR3/7 signaling pathways are necessary for the observed immediate and short-term protection. The results suggest that CAIVs provide short-term, non-specific protection against genetically unrelated respiratory pathogens. The additional benefits of CAIVs in mitigating acute respiratory infections for which vaccines are not yet available need to be assessed in future studies

Glycosylation of Hemagglutinin and Neuraminidase of Influenza A Virus as Signature for Ecological Spillover and Adaptation among Influenza Reservoirs

Glycosylation of the hemagglutinin (HA) and neuraminidase (NA) of the influenza provides crucial means for immune evasion and viral fitness in a host population. However, the time-dependent dynamics of each glycosylation sites have not been addressed. We monitored the potential N-linked glycosylation (NLG) sites of over 10,000 HA and NA of H1N1 subtype isolated from human, avian, and swine species over the past century. The results show a shift in glycosylation sites as a hallmark of 1918 and 2009 pandemics, and also for the 1976 “abortive pandemic”. Co-segregation of particular glycosylation sites was identified as a characteristic of zoonotic transmission from animal reservoirs, and interestingly, of “reverse zoonosis” of human viruses into swine populations as well. After the 2009 pandemic, recent isolates accrued glycosylation at canonical sites in HA, reflecting gradual seasonal adaptation, and a novel glycosylation in NA as an independent signature for adaptation among humans. Structural predictions indicated a remarkably pleiotropic influence of glycans on multiple HA epitopes for immune evasion, without sacrificing the receptor binding of HA or the activity of NA. The results provided the rationale for establishing the ecological niche of influenza viruses among the reservoir and could be implemented for influenza surveillance and improving pandemic preparedness

Pan-Influenza A Protection by Prime–Boost Vaccination with Cold-Adapted Live-Attenuated Influenza Vaccine in a Mouse Model

Influenza virus infections continually pose a major public health threat with seasonal epidemics and sporadic pandemics worldwide. While currently licensed influenza vaccines provide only strain-specific protection, antigenic drift and shift occasionally render the viruses resistant to the host immune responses, which highlight the need for a vaccine that provides broad protection against multiple subtypes. In this study, we suggest a vaccination strategy using cold-adapted, live attenuated influenza vaccines (CAIVs) to provide a broad, potent, and safe cross-protection covering antigenically distinct hemagglutinin (HA) groups 1 and 2 influenza viruses. Using a mouse model, we tested different prime–boost combinations of CAIVs for their ability to induce humoral and T-cell responses, and protective efficacy against H1 and H5 (HA group 1) as well as H3 and H7 (HA group 2) influenza viruses. Notably, even in the absence of antibody-mediated neutralizing activity or HA inhibitory activity in vitro, CAIVs provided a potent protection against heterologous and heterosubtypic lethal challenges in vivo. Heterologous combination of prime (H1)–boost (H5) vaccine strains showed the most potent cross-protection efficacy. In vivo depletion experiments demonstrated not only that T cells and natural killer cells contributed to the cross-protection, but also the involvement of antibody-dependent mechanisms for the cross-protection. Vaccination-induced antibodies did not enhance the infectivity of heterologous viruses, and prime vaccination did not interfere with neutralizing antibody generation by the boost vaccination, allaying vaccine safety concerns associated with heterogeneity between the vaccines and challenge strains. Our data show that CAIV-based strategy can serve as a simple but powerful option for developing a “truly” universal influenza vaccine providing pan-influenza A protection, which has not been achieved yet by other vaccine strategies. The promising results of potency, breadth, and safety demonstrated in the mouse model support further studies in higher animal models for clinical relevance