Effect of brazilian propolis on exacerbation of respiratory syncytial virus infection in mice exposed to tetrabromobisphenol a, a brominated flame retardant

Modulation of innate immunity related genes resulting in prophylactic antimicrobial and antiviral properties

BACKGROUND

The innate immunity acts during the early phases of infection and its failure in response to a multilayer network of co-infections is cause of immune system dysregulation. Epidemiological SARS-CoV-2 infections data, show that Influenza Virus (FLU-A-B-C) and Respiratory Syncytial Virus (RSV) are co-habiting those respiratory traits. These viruses, especially in children (mostly affected by 'multi-system inflammatory syndrome in children' [MIS-C] and the winter pandemic FLU), in the aged population, and in 'fragile' patients are causing alteration in immune response. Then, bacterial and fungal pathogens are also co-habiting the upper respiratory traits (e.g., Staphylococcus aureus and Candida albicans), thus contributing to morbidity in those COVID-19 affected patients.

METHODS

Liquid chromatography coupled with high-resolution mass spectrometry using the quadrupole orbital ion trap analyser (i.e., UHPLC-Q-Orbitrap HRMS) was adopted to measure the polyphenols content of a new nutraceutical formula (Solution-3). Viral infections with SARS-CoV-2 (EG.5), FLU-A and RSV-A viruses (as performed in BLS3 authorised laboratory) and real time RT-PCR (qPCR) assay were used to test the antiviral action of the nutraceutical formula. Dilution susceptibility tests have been used to estimate the minimum inhibitory and bactericidal concentration (MIC and MBC, respectively) of Solution-3 on a variety of microorganisms belonging to Gram positive/ negative bacteria and fungi. Transcriptomic data analyses and functional genomics (i.e., RNAseq and data mining), coupled to qPCR and ELISA assays have been used to investigate the mechanisms of action of the nutraceutical formula on those processes involved in innate immune response.

RESULTS

Here, we have tested the combination of natural products containing higher amounts of polyphenols (i.e., propolis, Verbascum thapsus L., and Thymus vulgaris L.), together with the inorganic long chain polyphosphates 'polyPs' with antiviral, antibacterial, and antifungal behaviours, against SARS-CoV-2, FLU-A, RSV-A, Gram positive/ negative bacteria and fungi (i.e., Candida albicans). These components synergistically exert an immunomodulatory action by enhancing those processes involved in innate immune response (e.g., cytokines: IFNγ, TNFα, IL-10, IL-6/12; chemokines: CXCL1; antimicrobial peptides: HBD-2, LL-37; complement system: C3).

CONCLUSION

The prophylactic antimicrobial success of this nutraceutical formula against SARS-CoV-2, FLU-A and RSV-A viruses, together with the common bacteria and fungi co-infections as present in human oral cavity, is expected to be valuable.

Hive Products: Composition, Pharmacological Properties, and Therapeutic Applications

Beekeeping provides products with nutraceutical and pharmaceutical characteristics. These products are characterized by abundance of bioactive compounds. For different reasons, honey, royal jelly, propolis, venom, and pollen are beneficial to humans and animals and could be used as therapeutics. The pharmacological action of these products is related to many of their constituents. The main bioactive components of honey include oligosaccharides, methylglyoxal, royal jelly proteins (MRJPs), and phenolics compounds. Royal jelly contains jelleins, royalisin peptides, MRJPs, and derivatives of hydroxy-decenoic acid, particularly 10-hydroxy-2-decenoic acid (10-HDA), which possess antibacterial, anti-inflammatory, immunomodulatory, neuromodulatory, metabolic syndrome-preventing, and anti-aging properties. Propolis has a plethora of activities that are referable to compounds such as caffeic acid phenethyl ester. Peptides found in bee venom include phospholipase A2, apamin, and melittin. In addition to being vitamin-rich, bee pollen also includes unsaturated fatty acids, sterols, and phenolics compounds that express antiatherosclerotic, antidiabetic, and anti-inflammatory properties. Therefore, the constituents of hive products are particular and different. All of these constituents have been investigated for their properties in numerous research studies. This review aims to provide a thorough screening of the bioactive chemicals found in honeybee products and their beneficial biological effects. The manuscript may provide impetus to the branch of unconventional medicine that goes by the name of apitherapy.

Cellular and physiological mechanisms of halogenated and organophosphorus flame retardant toxicity

Flame retardants (FRs) are chemical substances used to inhibit the spread of fire in numerous industrial applications, and their abundance in modern manufactured products in the indoor and outdoor environment leads to extensive direct and food chain exposure of humans. Although once considered relatively non-toxic, FRs are demonstrated by recent literature to have disruptive effects on many biological processes, including signaling pathways, genome stability, reproduction, and immune system function. This review provides a summary of research investigating the impact of major groups of FRs, including halogenated and organophosphorus FRs, on animals and humans in vitro and/or in vivo. We put in focus those studies that explained or referenced the modes of FR action at the level of cells, tissues and organs. Since FRs are highly hydrophobic chemicals, their biophysical and biochemical modes of action usually involve lipophilic interactions, e.g. with biological membranes or elements of signaling pathways. We present selected toxicological information about these molecular actions to show how they can lead to damaging membrane integrity, damaging DNA and compromising its repair, changing gene expression, and cell cycle as well as accelerating cell death. Moreover, we indicate how this translates to deleterious bioactivity of FRs at the physiological level, with disruption of hormonal action, dysregulation of metabolism, adverse effects on male and female reproduction as well as alteration of normal pattern of immunity. Concentrating on these subjects, we make clear both the advances in knowledge in recent years and the remaining gaps in our understanding, especially at the mechanistic level.

The Potential Use of Propolis as a Primary or an Adjunctive Therapy in Respiratory Tract-Related Diseases and Disorders: A Systematic Scoping Review

Propolis is a resinous beehive product that is collected by the bees from plant resin and exudates, to protect and maintain hive homeostasis. Propolis has been used by humans therapeutically to treat many ailments including respiratory tract-related diseases and disorders. The aim of the present systematic scoping review is to evaluate the experimental evidence to support the use of propolis as a primary or an adjunctive therapy in respiratory tract-related diseases and disorders. After applying the exclusion criteria, 158 research publications were retrieved and identified from Scopus, Web of Science, Pubmed, and Google Scholar. The key themes of the included studies were pathogenic infection-related diseases and disorders, inflammation-related disorders, lung cancers, and adverse effects. Furthermore, the potential molecular and biochemical mechanisms of action of propolis in alleviating respiratory tract-related diseases and disorders are discussed. In conclusion, the therapeutic benefits of propolis have been demonstrated by various in vitro studies, in silico studies, animal models, and human clinical trials. Based on the weight and robustness of the available experimental and clinical evidence, propolis is effective, either as a primary or an adjunctive therapy, in treating respiratory tract-related diseases.

The antiviral and immunomodulatory activities of propolis: An update and future perspectives for respiratory diseases

Propolis is a complex natural product that possesses antioxidant, anti‐inflammatory, immunomodulatory, antibacterial, and antiviral properties mainly attributed to the high content in flavonoids, phenolic acids, and their derivatives. The chemical composition of propolis is multifarious, as it depends on the botanical sources from which honeybees collect resins and exudates. Nevertheless, despite this variability propolis may have a general pharmacological value, and this review systematically compiles, for the first time, the existing preclinical and clinical evidence of propolis activities as an antiviral and immunomodulatory agent, focusing on the possible application in respiratory diseases. In vitro and in vivo assays have demonstrated propolis broad‐spectrum effects on viral infectivity and replication, as well as the modulatory actions on cytokine production and immune cell activation as part of both innate and adaptive immune responses. Clinical trials confirmed propolis undeniable potential as an effective therapeutic agent; however, the lack of rigorous randomized clinical trials in the context of respiratory diseases is tangible. Since propolis is available as a dietary supplement, possible use for the prevention of respiratory diseases and their deleterious inflammatory drawbacks on the respiratory tract in humans is considered and discussed. This review opens up new perspectives on the clinical investigation of neglected propolis biological properties which, now more than ever, are particularly relevant with respect to the recent outbreaks of pandemic respiratory infections.

Pharmaceutical Prospects of Bee Products: Special Focus on Anticancer, Antibacterial, Antiviral, and Antiparasitic Properties

Bee products have long been used in traditional healing practices to treat many types of disorders, including cancer and microbial-related diseases. Indeed, several chemical compounds found in bee products have been demonstrated to display anticancer, antibacterial, antiviral, and antiparasitic properties. With the improvement of research tools and in view of recent advances related to bee products, this review aims to provide broad yet detailed insight into the pharmaceutical prospects of bee products such as honey, propolis, bee pollen, royal jelly, bee bread, beeswax, and bee venom, in the domain of cancer and infectious disease management. Available literature confirms the efficacy of these bee products in the alleviation of cancer progression, inhibition of bacterial and viral proliferation, and mitigation of parasitic-related symptoms. With such potentials, bioactive components isolated from the bee products can be used as an alternative approach in the long-run effort to improve humans’ health at a personal and community level.

Brazilian propolis (AF-08) inhibits collagen-induced platelet aggregation without affecting blood coagulation

Brazilian propolis (AF-08) is a dietary supplement containing a variety of flavonoids. It is used worldwide as a folk medicine. Flavonoids and a diet of fruits and vegetables containing them have been shown to reduce the risk of cardiovascular diseases (CVDs). Most of CVDs are caused by arterial thrombus formation. A thrombus is formed by the interaction between adhesion and aggregation of platelets to damaged blood vessels and blood coagulation consisting of extrisic and intrinsic pathways. Platelet aggregation and blood coagulation are closely linked to thrombosis. Therefore, we evaluated the effectiveness of AF-08 or its component flavonoids against thrombosis by examining their inhibition of platelet aggregation and blood coagulation. Human platelet-rich plasma was incubated with serial dilutions of AF-08 for 10 min to assess its inhibitory effect on platelet aggregation caused by collagen. The inhibitory effect of AF-08 on blood coagulation was evaluated by the prothrombin time (PT) and activated partial thromboplastin time (APTT), which reflect the coagulation function of extrinsic and intrinsic pathways, respectively. AF-08 significantly inhibited collagen-induced platelet aggregation but not PT and APTT, indicating that AF-08 inhibited platelet aggregation but not blood coagulation. Among three flavonoids contained in AF-08, apigenin and chrysin obviously inhibited platelet aggregation but the inhibitory effect of kaempferol was less effective. The three flavonoids did not affect PT and APTT. The inhibitory activity of AF-08 on human platelet aggregation without affecting blood coagulation was suggested to be partially due to apigenin and chrysin. AF-08 may be effective in suppressing platelet-based arterial thrombus formation and reducing the risk of CVDs.

Propolis antiviral and immunomodulatory activity: a review and perspectives for COVID-19 treatment

OBJECTIVES

Viral outbreaks are a frequent concern for humans. A great variety of drugs has been used to treat viral diseases, which are not always safe and effective and may induce adverse effects, indicating the need for new antiviral drugs extracted from natural sources. Propolis is a bee-made product exhibiting many biological properties. An overview of viruses, antiviral immunity, propolis safety and its immunomodulatory and antiviral action is reported, as well as perspectives for coronavirus disease 2019 (COVID-19) treatment. PubMed platform was used for data collection, searching for the keywords "propolis", "virus", "antiviral", "antimicrobial" and "coronavirus".

KEY FINDINGS

Propolis is safe and exerts antiviral and immunomodulatory activity; however, clinical trials should investigate its effects on individuals with viral diseases, in combination or not with antiviral drugs or vaccines.

SUMMARY

Regarding COVID-19, the effects of propolis should be investigated directly on the virus in vitro or on infected individuals alone or in combination with antiviral drugs, due to its immunomodulatory and anti-inflammatory action. Propolis administration simultaneously with vaccines should be analyzed, due to its adjuvant properties, to enhance the individuals' immune response. The search for therapeutic targets may be useful to find out how propolis can help to control COVID-19.

Bee products as a source of promising therapeutic and chemoprophylaxis strategies against COVID-19 (SARS-CoV-2)

The emergence of novel coronavirus (SARS‐CoV‐2) in 2019 in China marked the third outbreak of a highly pathogenic coronavirus infecting humans. The novel coronavirus disease (COVID‐19) spread worldwide, becoming an emergency of major international concern. However, even after a decade of coronavirus research, there are still no licensed vaccines or therapeutic agents to treat the coronavirus infection. In this context, apitherapy presents as a promising source of pharmacological and nutraceutical agents for the treatment and/or prophylaxis of COVID‐19. For instance, several honeybee products, such as honey, pollen, propolis, royal jelly, beeswax, and bee venom, have shown potent antiviral activity against pathogens that cause severe respiratory syndromes, including those caused by human coronaviruses. In addition, the benefits of these natural products to the immune system are remarkable, and many of them are involved in the induction of antibody production, maturation of immune cells, and stimulation of the innate and adaptive immune responses. Thus, in the absence of specific antivirals against SARS‐CoV‐2, apitherapy could offer one hope toward mitigating some of the risks associated with COVID‐19.

Mitochondrial-related effects of pentabromophenol, tetrabromobisphenol A, and triphenyl phosphate on murine BV-2 microglia cells

The predominant reliance on bromated flame retardants (BFRs) is diminishing with expanded use of alternative organophosphate flame retardants. However, exposure related issues for susceptible populations, the developing, infirmed, or aged, remain given environmental persistence and home-environment detection. In this regard, reports of flame retardant (FR)-related effects on the innate immune system suggest process by which a spectrum of adverse health effects could manifest across the life-span. As representative of the nervous system innate immune system, the current study examined changes in microglia following exposure to representative FRs, pentabromophenol (PBP), tetrabromobisphenol A (2,2',6,6',-tetrabromo-4,4'-isopropylidine diphenol; TBBPA) and triphenyl phosphate (TPP). Following 18hr exposure of murine BV-2 cells, at dose levels resulting in ≥80% viability (10 and 40 μM), limited alterations in pro-inflammatory responses were observed however, changes were observed in mitochondrial respiration. Basal respiration was altered by PBP; ATP-linked respiration by PBP and TBBPA, and maximum respiration by all three FRs. Basal glycolytic rate was altered by PBP and TBBPA and compensatory glycolysis by all three. Phagocytosis was decreased for PBP and TBBPA. NLRP3 inflammasome activation was assessed using BV-2-ASC (apoptosis-associated speck-like protein containing a CARD) reporter cells to visualize aggregate formation. PBP, showed a direct stimulation of aggregate formation and properties as a NLRP3 inflammasome secondary trigger. TBBPA showed indications of possible secondary triggering activity while no changes were seen with TPP. Thus, the data suggests an effect of all three FRs on mitochondria metabolism yet, different functional outcomes including, phagocytic capability and NLRP3 inflammasome activation.

Effect of inactivated Streptococcus pneumoniae as non-pathogenic particles on the severity of pneumonia caused by respiratory syncytial virus infection in mice

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We made inactivated Streptococcus pneumoniae (ISP) as non-pathogenic particles.

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We evaluated effects of ISP on development of pneumonia by RSV infection in mice.

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ISP didn’t show histopathological effects on lungs of RSV-infected mice.

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ISP reduced virus titer and infiltration of lymphocyte in the lungs.

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The inherent activity of ISP as particles in RSV infection is discussed.

The severity of pneumonia in respiratory syncytial virus (RSV) infection is strongly related to host immune response and external factors such as bacteria and environmental chemicals. We investigated the effect of inactivated Streptococcus pneumoniae (ISP) as non-pathogenic particles on the severity of pneumonia in RSV-infected mice. Mice were intranasally exposed to ISP before RSV infection. On day 5 post-infection, we examined tissues, virus titer, and infiltrated cells in the lungs. The ISP did not cause significant histopathological effects in the lungs of RSV infected mice, but reduced virus titer. It also reduced the ratio of lymphocyte infiltration into the lungs and consequently the ratio of macrophage increased. In addition, we found that ISP increased RANTES level in bronchoalveolar lavage fluid from RSV-infected mice on day 1 post-infection, but reduced type I interferon levels. Thus, ISP did not exacerbate pneumonia in RSV infection, rather, it might mildly reduce the severity. We characterize and discuss the inherent activity of ISP as non-pathogenic particles inducing the role of RANTES on the pneumonia in RSV infection.

Effect of Green and Brown Propolis Extracts on the Expression Levels of microRNAs, mRNAs and Proteins, Related to Oxidative Stress and Inflammation

A large body of evidence highlights that propolis exerts many biological functions that can be ascribed to its antioxidant and anti-inflammatory components, including different polyphenol classes. Nevertheless, the molecular mechanisms are yet unknown. The aim of this study is to investigate the mechanisms at the basis of propolis anti-inflammatory and antioxidant activities. The effects of two brown and green propolis extracts-chemically characterized by RP-HPLC-PDA-ESI-MSn-on the expression levels of miRNAs associated with inflammatory responses (miR-19a-3p and miR-203a-3p) and oxidative stress (miR-27a-3p and miR-17-3p), were determined in human keratinocyte HaCat cell lines, treated with non-cytotoxic concentrations. The results showed that brown propolis, whose major polyphenolic components are flavonoids, induced changes in the expression levels of all miRNAs, and was more active than green propolis (whose main polyphenolic components are hydroxycinnamic acid derivatives) which caused changes only in the expression levels of miR-19a-3p and miR-27a-3p. In addition, only brown propolis was able to modify (1) the expression levels of mRNAs, the target of the reported miRNAs, which code for Tumor Necrosis Factor-α (TNF-α), Nuclear Factor, Erythroid 2 Like 2 (NFE2L2) and Glutathione Peroxidase 2 (GPX2), and (2) the protein levels of TNF-α and NFE2L2. In conclusion, brown and green propolis, which showed different metabolite profiles, exert their biological functions through different mechanisms of action.

Activation of Cellular Immunity in Herpes Simplex Virus Type 1-Infected Mice by the Oral Administration of Aqueous Extract of Moringa oleifera Lam. Leaves

Moringa oleifera Lam. is used as a nutritive vegetable and spice. Its ethanol extract has been previously shown to be significantly effective in alleviating herpetic skin lesions in mice. In this study, we evaluated the alleviation by the aqueous extract (AqMOL) and assessed the mode of its anti-herpetic action in a murine cutaneous herpes simplex virus type 1 (HSV-1) infection model. AqMOL (300 mg/kg) was administered orally to HSV-1-infected mice three times daily on days 0 to 5 after infection. AqMOL significantly limited the development of herpetic skin lesions and reduced virus titers in the brain on day 4 without toxicity. Delayed-type hypersensitivity (DTH) reaction to inactivated HSV-1 antigen was significantly stronger in infected mice administered AqMOL and AqMOL augmented interferon (IFN)-γ production by HSV-1 antigen from splenocytes of HSV-1-infected mice at 4 days post-infection. AqMOL administration was effective in elevating the ratio of CD11b(+) and CD49b(+) subpopulations of splenocytes in infected mice. As DTH is a major host defense mechanism for intradermal HSV infection, augmentation of the DTH response by AqMOL may contribute to their efficacies against HSV-1 infection. These results provided an important insights into the mechanism by which AqMOL activates cellular immunity. Copyright © 2016 John Wiley & Sons, Ltd.

Titanium dioxide nanoparticles exacerbate pneumonia in respiratory syncytial virus (RSV)-infected mice

To reveal the effects of TiO2 nanoparticles, used in cosmetics and building materials, on the immune response, a respiratory syncytial virus (RSV) infection mouse model was used. BALB/c mice were exposed once intranasally to TiO2 at 0.5mg/kg and infected intranasally with RSV five days later. The levels of IFN-γ and chemokine CCL5, representative markers of pneumonia, in the bronchoalveolar lavage fluids of RSV-infected mice had increased significantly in TiO2-exposed mice compared with the control on day 5 post-infection, but not in uninfected mice. While pulmonary viral titers were not affected by TiO2 exposure, an increase in the infiltration of lymphocytes into the alveolar septa in lung tissues was observed. Immunohistochemical analysis revealed aggregation of TiO2 nanoparticles near inflammatory cells in the severely affected region. Thus, a single exposure to TiO2 nanoparticles affected the immune system and exacerbated pneumonia in RSV-infected mice.

Mucosal delivery of a double-stapled RSV peptide prevents nasopulmonary infection

Respiratory syncytial virus (RSV) infection accounts for approximately 64 million cases of respiratory disease and 200,000 deaths worldwide each year, yet no broadly effective prophylactic or treatment regimen is available. RSV deploys paired, self-associating, heptad repeat domains of its fusion protein, RSV-F, to form a fusogenic 6-helix bundle that enables the virus to penetrate the host cell membrane. Here, we developed hydrocarbon double-stapled RSV fusion peptides that exhibit stabilized α-helical structure and striking proteolytic resistance. Pretreatment with double-stapled RSV peptides that specifically bound to the RSV fusion bundle inhibited infection by both laboratory and clinical RSV isolates in cells and murine infection models. Intranasal delivery of a lead double-stapled RSV peptide effectively prevented viral infection of the nares. A chitosan-based nanoparticle preparation markedly enhanced pulmonary delivery, further preventing progression of RSV infection to the lung. Thus, our results provide a strategy for inhibiting RSV infection by mucosal and endotracheal delivery of double-stapled RSV fusion peptides.