Saccharomyces cerevisiae ß-glucan improves the response of trained macrophages to severe P. aeruginosa infections.

OBJECTIVE P. AERUGINOSA: (PA), the major pathogen of lung cystic fibrosis (CF), polarizes macrophages into hyperinflammatory tissue damaging phenotype. The main aim of this study was to verify whether training of macrophages with ß-glucan might improve their response to P. aeruginosa infections. METHODS: To perform this task C57BL/6 mice sensitive to infections with P. aeruginosa were used. Peritoneal macrophages were trained with Saccharomyces cerevisiae ß-glucan and exposed to PA57, the strong biofilm-forming bacterial strain isolated from the patient with severe lung CF. The release of cytokines and the expression of macrophage phenotypic markers were measured. A quantitative proteomic approach was used for the characterization of proteome-wide changes in macrophages. The effect of in vivo ß-glucan-trained macrophages in the air pouch model of PA57 infection was investigated. In all experiments the effect of trained and naïve macrophages was compared. RESULTS: Trained macrophages acquired a specific phenotype with mixed pro-inflammatory and pro-resolution characteristics, however they retained anti-bacterial properties. Most importantly, transfer of trained macrophages into infected air pouches markedly ameliorated the course of infection. PA57 bacterial growth and formation of biofilm were significantly suppressed. The level of serum amyloid A (SAA), a systemic inflammation biomarker, was reduced. CONCLUSIONS: Training of murine macrophages with S. cerevisiae ß-glucan improved macrophage defense properties along with inhibition of secretion of some detrimental inflammatory agents. We suggest that training of macrophages with such ß-glucans might be a new therapeutic strategy in P. aeruginosa biofilm infections, including CF, to promote eradication of pathogens and resolution of inflammation.

Biofilm-forming strains of P. aeruginosa and S. aureus isolated from cystic fibrosis patients differently affect inflammatory phenotype of macrophages.

OBJECTIVE: Lung cystic fibrosis (CF) is characterized by chronic infections and hyperinflammatory response of neutrophils and macrophages. P. aeruginosa (PA) and S. aureus (MSSA, MRSA) are major pathogens of advanced CF. The main goal of this study was to compare the inflammatory phenotype of murine C57BL/6 macrophages exposed to PA57 with that exposed to MSSA60, both strains isolated from the same patient with severe CF. In the present study, we used C57BL/6 mice sensitive to lung infection with P. aeruginosa. METHODS: We measured the release of cytokines and the expression of phenotypic markers of murine neutrophils and macrophages exposed to bacterial cells and biofilm components (i.e., EPS) of the selected bacteria. In addition, a quantitative proteomic approach was used for the characterization of proteome-wide changes in macrophages. RESULTS: Neutrophils stimulated with PA57 and MSSA60 strains produced hyperinflammatory pattern of cytokines. The pro-inflammatory impact of PA57 was significantly higher than that of MSSA60 (IL-6/IL-10 ratio: PA57 = 9.3 vs. MSSA60 = 1.7). Macrophages produced significantly lower amount of cytokines, but showed classical pattern of M1 markers (iNOS-High; arginase-1 and mannose receptor MRC1-Low). Importantly, as evidenced by proteomic analysis, PA57 and PA57-EPS were stronger inducers of M1 macrophage polarization than the MSSA60 counterparts. CONCLUSIONS: Our study demonstrated that strong biofilm P. aeruginosa strains, CF isolates, are dominant inducers of M1 macrophages, termed biofilm-associated macrophages (BAMs). We suggest that repolarization of detrimental BAMs might be a new therapeutic strategy to ameliorate the airway damage in CF.

Current Opinion on the Therapeutic Capacity of Taurine-Containing Halogen Derivatives in Infectious and Inflammatory Diseases.

Taurine haloamines, N-chlorotaurine (NCT, TauCl), and N-bromotaurine (NBT, TauBr) are formed by a reaction between taurine and hypohalous acids, HOCl and HOBr, respectively. The major source of endogenous taurine haloamines is neutrophils. Both NCT and NBT share strong anti-inflammatory and microbicidal activities supported by an absence of microbial resistance. In the light of these properties, a number of clinical studies have been performed to document their effectiveness in treatment of bacterial, fungal, and viral infections. The administration of NCT and NBT has been limited to topical application, as they are decomposed upon systemic delivery. This review summarizes current knowledge concerning the therapeutic use of NCT and NBT mainly in various skin disorders such as non-healing wounds, acne vulgaris, herpes zoster, and psoriasis. Moreover, the beneficial effect of NCT inhalation in early stages of COVID-19 and other viral respiratory infections is discussed. And finally, we would like to suggest that NCT might be used to inhibit the development of the cytokine storm through its capacity to suppress the production of IL-6.

Neutrophils as Sentinel Cells of the Immune System: A Role of the MPO-halide-system in Innate and Adaptive Immunity.

For decades, neutrophils were generally regarded as the cells of innate immunity with proinflammatory and phagocytic properties involved in a dual activity, beneficial (antimicrobial) and detrimental (tissue damage). Importantly, until the discovery of toll-like receptors (TLRs), a role of neutrophils in adaptive immunity was limited to the effector stage of humoral response and phagocytosis of opsonized antigens. Moreover, in common opinion, neutrophils, as well as the entire innate immune system, were not functionally associated with adaptive immunity. At the time we demonstrated protein chlorination by HOCl, the major product of neutrophil MPO-halide system enhances protein immunogenicity. Based on this discovery, we proposed, as the first, a new role for neutrophils as APC-accessory cells involved in the induction stage of adaptive immunity. Thereafter, we developed our theory concerning the role of neutrophils as the cells which link innate and adaptive immunity. We proposed that protein modification by HOCl may act as a neutrophildependent molecular tagging system, by which sentinel dendritic cells can faster recognise pathogen- derived antigens. Contemporaneously, it was demonstrated that taurine, the most abundant free amino acid in neutrophil cytosol and the major scavenger of HOCl, is a part of the oxidantantioxidant network and is responsible for the regulation and termination of acute inflammation. Moreover, it has been described, that taurine chloramine (TauCl), the physiological products of the reaction of HOCl with taurine, show anti-microbial and anti-inflammatory properties. In this review, the role of HOCl, taurine and TauCl in innate and adaptive immunity will be discussed.

Combined Biological Effects of N-Bromotaurine Analogs and Ibuprofen. Part I: Influence on Inflammatory Properties of Macrophages.

Taurine haloamines (N-chlorotaurine, N-bromotaurine) due to their strong antiseptic and anti-inflammatory properties are good candidates for topical application in treatment of skin inflammatory/infectious disorders. Recently, we have demonstrated that more stable N-bromotaurine analogs (N-dibromo-dimethyl taurine, N-monobromo-dimethyl taurine) and bromamine T show strong microbicidal and anti-inflammatory properties at concentrations well tolerated by human cells and tissue. Non-steroidal anti-inflammatory drugs (NSAIDs) with cyclooxygenase (COX) inhibitory activity are commonly used in various inflammatory diseases. However, systemic administration of NSAIDs may result in adverse side effects. For example, the use of ibuprofen in children with varicella is associated with enhanced serum levels of TNF-α and with increased risk of necrotizing soft tissue infections and secondary skin infections caused by invasive streptococci. The aim of this study was to examine combined immunomodulatory effects of bromamines and ibuprofen on J774.A1 macrophages. We have shown that the primary activity of ibuprofen, the inhibition of PGE2 production by activated macrophages was intensified in the presence of bromamines. Most importantly, the stimulatory effect of ibuprofen on production of inflammatory cytokines (TNF-α, IL-6) was inhibited by all tested bromamines. These observations indicate that bromamines may neutralize massive production of TNF-α at sites of inflammation, a side effect of ibuprofen. Therefore, we suggest that systemic administration of ibuprofen (NSAIDs) in treatment of inflammatory/infectious skin diseases should be supported by topical application of bromamines as an adjunctive therapy.

Combined Biological Effects of N-Bromotaurine Analogs and Ibuprofen. Part II: Influence on a Local Defense System.

The stable N-bromotaurine analogs (N-dibromo-dimethyl taurine, N-monobromo-dimethyl taurine), and bromamine T (BAT) show anti-inflammatory and microbicidal properties. These bromamines are good candidates for a treatment of skin infectious/inflammatory diseases as local antiseptics. Ibuprofen, a non-steroidal anti-inflammatory drug (NSAID), is commonly used in various infectious/inflammatory diseases due to its analgesic and antipyretic therapeutic effects. However, systemic administration of ibuprofen may also result in adverse side effects. It has been reported that ibuprofen enhances serum levels of TNF-α and worsens secondary skin infections caused by invasive streptococci (S. pyogenes). Recently we have demonstrated that bromamines inhibit the stimulatory effect of ibuprofen on the production of inflammatory cytokines (TNF-α, IL-6). The aim of this study was to examine the combined antibacterial actions of ibuprofen and bromamines against S. pyogenes and their joint effect on the generation of reactive oxygen species (ROS) by activated neutrophils and macrophages. We have shown that the microbicidal activity of bromamines against S. pyogenes was not altered by ibuprofen. On the other hand, co-administration of ibuprofen and bromamines markedly decreased the generation of ROS by activated neutrophils and macrophages. Finally, we discuss how the antioxidant combined effect of bromamines and ibuprofen may affect a local defense system.

Pseudomonas aeruginosa biofilm is a potent inducer of phagocyte hyperinflammation.

OBJECTIVE: Pseudomonas aeruginosa effectively facilitate resistance to phagocyte killing by biofilm formation. However, the cross talk between biofilm components and phagocytes is still unclear. We hypothesize that a biofilm provides a concentrated extracellular source of LPS, DNA and exopolysaccharides (EPS), which polarize neighbouring phagocytes into an adverse hyperinflammatory state of activation. METHODS: We measured the release of a panel of mediators produced in vitro by murine neutrophils and macrophages exposed to various biofilm components of P. aeruginosa cultures. RESULTS: We found that conditioned media from a high biofilm-producing strain of P. aeruginosa, PAR5, accumulated high concentrations of extracellular bacterial LPS, DNA and EPS by 72 h. These conditioned media induced phagocytes to release a hyperinflammatory pattern of mediators, with enhanced levels of TNF-α, IL-6, IL12p40, PGE2 and NO. Moreover, the phagocytes also upregulated COX-2 and iNOS with no influence on the expression of arginase-1. CONCLUSIONS: Phagocytes exposed to biofilm microenvironment, called by us biofilm-associated neutrophils/macrophages (BANs/BAMs), display secretory properties similar to that of N1/M1-type phagocytes. These results suggest that in vivo high concentrations of LPS and DNA, trapped in biofilm by EPS, might convert infiltrating phagocytes into cells responsible for tissue injury without direct contact with bacteria and phagocytosis.

Air particulate matter SRM 1648a primes macrophages to hyperinflammatory response after LPS stimulation.

OBJECTIVE: Exposure to air particulate matter (PM) is associated with chronic inflammatory and autoimmune diseases. Macrophages are responsible for the regulation of chronic inflammation. However, whether PM affects macrophage polarization remains unclear. The aim of this study was to evaluate whether nontoxic concentrations of urban PM are able to prime macrophages to altered inflammatory response upon LPS challenge. METHODS: We used two forms of the urban particulate matter SRM 1648a, intact PM and PM deprived of organic compounds (PM∆C). Peritoneal murine macrophages were exposed to different concentrations of PM for 24 h and then challenged with LPS. Production of inflammatory mediators by macrophages was measured to test immunostimulatory/priming capacity of PM. RESULTS: Particulate matter used at non-cytotoxic concentrations induced a dose-dependent production of proinflammatory cytokines (TNF-α, IL-6, IL-12p40). By contrast, PM∆C were not able to stimulate macrophages. However, macrophages primed with both forms of PM show proinflammatory response upon LPS challenge. CONCLUSIONS: Our data indicate that exposure of macrophages to low concentrations of PM may prime the cells to hyperinflammatory response upon contact with LPS. Further studies are necessary to explain whether the exposure of patients suffering from chronic inflammatory diseases to particulate matter is responsible for the exacerbation of clinical symptoms during bacterial infections.

[Mechanism and risk factors of oral biofilm formation]. / Mechanizm i czynniki ryzyka powstawania biofilmu bakteryjnego jamy ustnej.

Recent microbiological investigations completely changed our understanding of the role of biofilm in the formation of the mucosal immune barrier and in pathogenesis of chronic inflammation of bacterial etiology. It is now clear that formation of bacterial biofilm on dental surfaces is characteristic for existence of oral microbial communities. It has also been proved that uncontrolled biofilms on dental tissues, as well as on different biomaterials (e.g. orthodontic appliances), are the main cause of dental diseases such as dental caries and periodontitis. The aim of this paper is to explain mechanisms and consequences of orthodontic biofilm formation. We will discuss current opinions on the influence of different biomaterials employed for orthodontic treatment in biofilm formation and new strategies employed in prevention and elimination of oral biofilm ("dental plaque").

Influence of taurine haloamines (TauCl and TauBr) on the development of Pseudomonas aeruginosa biofilm: a preliminary study.

Biofilms are consortia of microorganisms (sessile cells) that form on various surfaces including mucosal membranes or teeth. Bacterial biofilms cause many human infections such as chronic sinusitis, acne vulgaris, periodontal diseases, and chronic wounds. These infections are persistent as they show increased resistance to antibiotics and host defense system. Taurine chloramine (TauCl) and taurine bromamine (TauBr) are the physiological products of activated neutrophils, resulting from the reaction between taurine with hypochlorous acid (HOCl) and hypobromous acid (HOBr), respectively. It has been shown in vitro that taurine haloamines exert antimicrobial properties against various pathogenic bacteria. Moreover, clinical studies have shown that both haloamines are effective in the local treatment of skin and mucose infections, including biofilm-related infections. Nevertheless, it has been not tested yet whether they can kill bacteria hidden in biofilm or disrupt biofilm structure. In this study we have investigated the capacity of TauCl and TauBr to inhibit in vitro the formation of P. aeruginosa biofilm. We have also tested their ability to destroy the mature biofilm. Our results suggest that TauBr is able to inhibit in vitro the formation of P. aeruginosa biofilm but cannot destroy the mature biofilm and effectively killed hidden bacteria. In further studies, the combined effect of TauBr and DNase, one of suggested biofilm inhibitors, was tested. Together, we conclude that TauBr is a better than TauCl candidate for local therapy of biofilm-related infections. However, a combined therapy, an application of TauBr together with other anti-biofilm agents (e.g., DNase), seems to be more promising.

[Taurine chloramine and its potential therapeutical application]. / Chloramina tauryny i jej potencjalne zastosowanie w terapii.

Taurine chloramine (TauCl) is generated at the site of inflammation as a result of reaction of taurine with hypochlorous acid (HOCl), the product of myeloperoxidase-halide system of neutrophils. It has been shown in vitro that TauCl exerts both anti-inflammatory and anti-microbial properties. This review is an attempt to summarize the recent clinical studies in which TauCl was used for local treatment of infectious and inflammatory diseases.

Taurine haloamines and heme oxygenase-1 cooperate in the regulation of inflammation and attenuation of oxidative stress.

Taurine chloramine (TauCl) and Taurine bromamine (TauBr), products of the neutrophil myeloperoxidase halide system, exert anti-inflammatory properties. They inhibit the production of a variety of inflammatory mediators, such as prostaglandin E2 (PGE2), nitric oxide (NO) and proinflammatory cytokines. Heme oxygenase-1 (HO-1), a stress inducible enzyme, degrades heme to biliverdin, free iron and carbon monoxide (CO), which are involved in the anti-inflammatory and antioxidant actions of HO-1. Recently we have demonstrated that taurine haloamines induce the expression of HO-1 in inflammatory cells. In this study we examined whether HO-1 participates in taurine haloamines-mediated suppression of proinflammatory cytokine production. We have shown that TauCl/TauBr and CO inhibit the production of TNF-alpha, IL-12 and IL-6, in a similar dose-dependent manner. However, the suppressor activity of TauCl was not altered in HO-1 deficient mice. Therefore, HO-1 and TauCl may independently regulate the production of proinflammatory cytokines. We suggest that TauCl and TauBr provide a link between the two antioxidant systems: the cysteine pathway and the heme oxygenase system.

Topical taurine bromamine, a new candidate in the treatment of moderate inflammatory acne vulgaris: a pilot study.

Taurine bromamine (TauBr), the product of taurine and hypobromous acid (HOBr), exerts anti-inflammatory and antibacterial properties. Recently we have shown that Propionibacterium acnes, a potential pathogenic agent of acne, is extremely sensitive to TauBr. As topical antibiotics are associated with the emergence of resistant bacteria, TauBr seems to be a good candidate for topical therapy for acne vulgaris. In our double blind investigation, the efficacy and safety of 3.5 mM TauBr cream was evaluated. 1% Clindamycin gel (Clindacin T), one of the most common topical agents in the treatment of acne vulgaris, was used as a control. Forty patients with mild to moderate inflammatory facial acne vulgaris were randomly treated with either TauBr or clindamycin for 6 weeks, twice-a-day. More than 80% of the patients markedly improved with both treatments, without any adverse effects observed. Both TauBr and clindamycin produced a significant reduction in inflammatory skin lesion counts (papules/ pustules). After 6 weeks, comparable reductions of acne lesions, 65% and 68%, were observed in the TauBr and clindamycin groups, respectively. In conclusion, these data support our concept that TauBr can be used as a topical agent in the treatment of acne vulgaris, especially in patients who have already developed antibiotic resistance.