leukotoxin and Inflammation

Linoleic acid (LA) is the most abundant polyunsaturated fatty acid found in the Western diet. Cytochrome P450-derived LA metabolites 9,10-epoxyoctadecenoic acid (9,10-EpOME), 12,13-epoxyoctadecenoic acid (12,13-EpOME), 9,10-dihydroxy-12Z-octadecenoic acid (9,10-DiHOME) and 12,13-dihydroxy-9Z-octadecenoic acid (12,13-DiHOME) have been studied for their association with various disease states and biological functions. Previous studies of the EpOMEs and DiHOMEs have focused on their roles in cytotoxic processes, primarily in the inhibition of the neutrophil respiratory burst. More recent research has suggested the DiHOMEs may be important lipid mediators in pain perception, altered immune response and brown adipose tissue activation by cold and exercise. The purpose of this review is to summarize the current understanding of the physiological and pathophysiological roles and modes of action of the EpOMEs and DiHOMEs in health and disease.

Topics: Adipose Tissue, Brown; Analgesics; Animals; Cytochrome P-450 Enzyme System; Endocrine System; Epoxide Hydrolases; Exotoxins; Humans; Immune System; Inflammation; Linoleic Acid; Lipids; Lung; Mice; Neutrophils; Oleic Acids; Oxidation-Reduction; Pain Management; Respiratory Burst; Stearic Acids

Pistachio nut ingestion (3 oz./d, two weeks) was tested for effects on exercise performance and 21-h post-exercise recovery from inflammation, oxidative stress, immune dysfunction, and metabolite shifts.. Using a randomized, crossover approach, cyclists (N = 19) engaged in two 75-km time trials after 2-weeks pistachio or no pistachio supplementation, with a 2-week washout period. Subjects came to the lab in an overnight fasted state, and ingested water only or 3 oz. pistachios with water before and during exercise. Blood samples were collected 45 min pre-exercise, and immediately post-, 1.5-h post-, and 21-h post-exercise, and analyzed for plasma cytokines, C-reactive protein (CRP), F2-isoprostanes (F2-IsoP), granulocyte phagocytosis (GPHAG) and oxidative burst activity (GOBA), and shifts in metabolites.. Performance time for the 75-km time trial was 4.8% slower under pistachio conditions (2.84 ± 0.11 and 2.71 ± 0.07 h, respectively, P = 0.034). Significant time effects were shown for plasma cytokines, CRP, F2-IsoP, GPHAG, and GOBA, with few group differences. Metabolomics analysis revealed 423 detectable compounds of known identity, with significant interaction effects for 19 metabolites, especially raffinose, (12Z)-9,10-Dihydroxyoctadec-12-enoate (9,10-DiHOME), and sucrose. Dietary intake of raffinose was 2.19 ± 0.15 and 0.35 ± 0.08 mg/d during the pistachio and no pistachio periods, and metabolomics revealed that colon raffinose and sucrose translocated to the circulation during exercise due to increased gut permeability. The post-exercise increase in plasma raffinose correlated significantly with 9,10-DiHOME and other oxidative stress metabolites.. In summary, 2-weeks pistachio nut ingestion was associated with reduced 75-km cycling time trial performance and increased post-exercise plasma levels of raffinose, sucrose, and metabolites related to leukotoxic effects and oxidative stress.. ClinicalTrials.gov NCT01821820.

Topics: Adult; Athletes; Bicycling; C-Reactive Protein; Cross-Over Studies; Cytokines; Dietary Supplements; Exotoxins; F2-Isoprostanes; Granulocytes; Humans; Inflammation; Intestinal Mucosa; Male; Metabolomics; Middle Aged; Mitochondria; Oxidative Stress; Permeability; Phagocytosis; Physical Exertion; Pistacia; Raffinose; Sucrose

A relationship between rheumatoid arthritis (RA) and periodontitis has been suggested from findings that individuals with RA are prone to have advanced periodontitis and vice versa. In search of possible common pathogenetic features of these two diseases, we investigated the presence of citrullinated proteins and expression of endogenous peptidylarginine deiminases (PAD2 and PAD4), in periodontal tissue of individuals with periodontitis and healthy controls, in relation to the periodontal pathogens Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans), producing leukotoxin as virulence factor. These two oral bacteria have been suggested to be linked to anti-citrullinated protein antibodies in patients with RA.. Gingival tissue biopsies were obtained from 15 patients with periodontitis and 15 individuals without periodontal disease. Presence of CD3-positive lymphocytes, citrullinated proteins, PAD2, PAD4, P. gingivalis as well as A. actinomycetemcomitans and Mannheimia haemolytica produced leukotoxins were analysed by immunohistochemistry, followed by triple-blind semi-quantitative analysis. Mann-Whitney and Fisher's exact tests were used to analyse differences between groups. PADI2 and PADI4 mRNA levels were assessed by RT-qPCR and analysed using Wilcoxon signed rank test.. Increased staining of citrullinated proteins was observed in gingival connective tissue from subjects with periodontitis (80%, 12/15) compared to healthy gingival tissue (27%, 4/15), whereas no differences were observed in gingival epithelium. There was also an increased staining of the citrullinating enzymes PAD2 and PAD4 in gingival connective tissue of patients with periodontitis whereas similar levels of PAD2 and PAD4 were observed in the gingival epithelium of the two groups. Similarly, the mRNA levels of PADI2 and PADI4 were also increased in the gingival tissue of patients with periodontitis compared to healthy controls. Furthermore, presence of P. gingivalis and leukotoxins was comparable in both epithelium and connective tissue, from the different investigated individuals with and without periodontitis, and there were no correlations between the presence of periodontal pathogens and the expression of citrullinated proteins or PAD enzymes.. Chronic gingival inflammation is associated with increased local citrullination and PAD2 and PAD4 expression in periodontitis. The increased citrullination and PAD2 and PAD4 expression in periodontitis were, however, independent of the presence of periodontal pathogen P. gingivalis and A. actinomycetemcomitans leukotoxin.

Topics: Adult; Aggregatibacter actinomycetemcomitans; Arthritis, Rheumatoid; Citrullination; Exotoxins; Gingiva; Humans; Inflammation; Lymphocytes; Middle Aged; Periodontitis; Porphyromonas gingivalis; Protein-Arginine Deiminases; RNA, Messenger

Staphylococcus aureus produces numerous molecules that facilitate survival in the host. We recently identified a novel S. aureus leukotoxin (leukotoxin GH [LukGH]) using proteomics, but its role in virulence remains unclear. Here we investigated the role of LukGH in vivo.. We tested cytotoxicity of LukGH toward polymorphonuclear leukocytes (PMNs) from mice, rabbits, monkeys, and humans. LukGH was administered to mice, rabbits, and a cynomolgus monkey by subcutaneous or intradermal injection to assess cytotoxicity or host response in vivo. The effects of LukGH in vivo were compared with those of Panton-Valentine leukocidin (PVL), a well-characterized S. aureus leukotoxin. The contribution of LukGH to S. aureus infection was tested using mouse and rabbit infection models.. Susceptibility of PMNs to LukGH was similar between humans and cynomolgus monkeys, and was greater than that of rabbits, which in turn was greater than that of mice. LukGH or PVL caused skin inflammation in rabbits and a monkey, but deletion of neither lukGH nor lukGH and lukS/F-PV reduced severity of USA300 infections in rabbits or mice. Rather, some disease parameters (eg, rabbit abscess size) were increased following infection with a lukGH and lukS/F-PV deletion strain.. Our findings indicate that S. aureus leukotoxins enhance the host inflammatory response and influence the outcome of infection.

Topics: Animals; Disease Models, Animal; Exotoxins; Humans; Inflammation; Injections, Intradermal; Injections, Subcutaneous; Macaca fascicularis; Male; Mice; Neutrophils; Rabbits; Staphylococcal Infections; Staphylococcus aureus; Virulence Factors

Psoriasis is a very common chronic skin disease, affecting 2-3% of the world's population or more than 125 million individuals worldwide. The characteristic lesion of psoriasis is due to rapid proliferation and shortened transition of keratinocytes through the epidermis. Proinflammatory white blood cells (WBCs) migrate into the psoriatic plaques, and the pathogenic cytokine environment causes the changes in keratinocyte proliferation and differentiation. Enhanced migration of WBCs is due to the upregulation and activation of adhesion molecules such as leukocyte function antigen-1 (LFA-1), which binds intercellular adhesion molecule-1 (ICAM-1) on endothelial cells. Targeting LFA-1 and preventing interaction with ICAM-1 has proven an effective strategy for treating psoriasis. We show here that a natural leukocyte-targeting bacterial protein (leukotoxin (LtxA)) that binds LFA-1 can inhibit proliferation of activated WBCs from psoriasis patients and demonstrates significant therapeutic efficacy in a psoriasis xenograft transplantation model. In ex vivo studies, LtxA preferentially targeted proinflammatory WBC subtypes, including activated CD25(+) T cells and CD14(+)CD16(+) monocytes. LFA-1 has been shown to have a significant role in the pathogenesis of numerous autoimmune and inflammatory diseases, and we propose that LtxA may be a highly effective agent for treating these diseases.

Topics: Adult; Animals; Bacterial Proteins; Cell Differentiation; Cell Movement; Cell Proliferation; Epidermis; Exotoxins; Female; Humans; Inflammation; Intercellular Adhesion Molecule-1; Interleukin-2 Receptor alpha Subunit; Jurkat Cells; Keratinocytes; Leukocytes; Lipopolysaccharide Receptors; Lymphocyte Function-Associated Antigen-1; Male; Mice; Middle Aged; Psoriasis; Receptors, IgG

Aggregatibacter (Actinobacillus) actinomycetemcomitans is a gram-negative oral pathogen that is the etiologic agent of localized aggressive periodontitis and systemic infections. A. actinomycetemcomitans produces leukotoxin (LtxA), which is a member of the RTX (repeats in toxin) family of secreted bacterial toxins and is known to target human leukocytes and erythrocytes. To better understand how LtxA functions as a virulence factor, we sought to detect and study potential A. actinomycetemcomitans proteins that interact with LtxA. We found that Cu,Zn superoxide dismutase (SOD) interacts specifically with LtxA. Cu,Zn SOD was purified from A. actinomycetemcomitans to homogeneity and remained enzymatically active. Purified Cu,Zn SOD allowed us to isolate highly specific anti-Cu,Zn SOD antibody and this antibody was used to further confirm protein interaction. Cu,Zn SOD-deficient mutants displayed decreased survival in the presence of reactive oxygen and nitrogen species and could be complemented with wild-type Cu,Zn SOD in trans. We suggest that A. actinomycetemcomitans Cu,Zn SOD may protect both bacteria and LtxA from reactive species produced by host inflammatory cells during disease. This is the first example of a protein-protein interaction involving a bacterial Cu,Zn SOD.

Topics: Aggregatibacter actinomycetemcomitans; Exotoxins; HL-60 Cells; Humans; Inflammation; Reactive Oxygen Species; Superoxide Dismutase; Virulence Factors

To investigate rheologic properties of bovine neutrophils that may result in adhesion molecule-independent sequestration of neutrophils in inflamed lungs of cattle.. Healthy 2- to 4-week-old male Holstein calves.. Neutrophil deformability, filamentous actin (F-actin) content, and CD11b expression was determined for unstimulated bovine neutrophils and bovine neutrophils incubated with the inflammatory mediators tumor necrosis factor-alpha (TNF), platelet-activating factor (PAF), interleukin-8 (IL-8), zymosan-activated plasma (ZAP), Pasteurella haemolytica-derived lipopolysaccharide (LPS), and P haemolytica leukotoxin. Neutrophils were separated into 3 subpopulations on the basis of size. The Factin content and CD11 b expression were evaluated by use of flow cytometry. Leukocyte deformability was evaluated by filtration of dilute whole blood.. The subpopulation of the smallest-sized neutrophils (>90% of neutrophils) contained little F-actin. A subpopulation of slightly larger neutrophils had a profound increase in F-actin content and CD11 b expression. The subpopulation of the largest neutrophils had increased F-actin content and CD11b expression, compared with those for both subpopulations of smaller neutrophils. Incubation of neutrophils with PAF and ZAP but not TNF, IL-8, LPS, or leukotoxin, resulted in decreased neutrophil deformability and increased F-actin content. Incubation with PAF and TNF induced an increase in size of neutrophils.. Size can be used to identify subpopulations of large and rigid neutrophils in blood samples from healthy calves. Platelet-activating factor and activated complement fragments are potent inducers of F-actin formation and neutrophil rigidity. Physical changes in neutrophils may impede their transit through lung microvasculature and result in leukocyte trapping independent of adhesion molecule interactions with endothelial cells.

Topics: Actins; Animals; Blood; Cattle; Cell Membrane; Exotoxins; Inflammation; Interleukin-8; Lipopolysaccharides; Macrophage-1 Antigen; Male; Mannheimia haemolytica; Neutrophils; Platelet Activating Factor; Tumor Necrosis Factor-alpha; Zymosan

Panton-Valentine leucocidin arises from the combination of one S component (LukS-PV) with one F component (LukF-PV), whereas gamma-haemolysin comprises two S components (HlgA and HlgC) with one F component HlgB. The intravitreal injection of rabbit eye with the six combinations (S + F) of channel-forming leucotoxins produced by Staphylococcus aureus ATCC 49775 induced acute inflammatory reactions depending on time and doses of toxins. These reactions involved posterior chamber as well as anterior chamber and conjunctiva, eyelids and annexes. Histological examination confirmed the involvement of eye tissues and the disruption of the retinal barrier. The lesions began only 4 h after injections and persisted for at least 5 days. Clinical and biological effects of each leucotoxin were modulated by the speed of onset and intensity of inflammation and necrosis, leading to a functional classification according to the severity of the lesions (HlgA + LukF-PV > HlgA + HlgB > or = LukS-PV + HlgB > or = LukS-PV + LukF-PV > HlgC + HlgB > or = HlgC + LukF-PV). Moreover, N-acetyl beta-D glucosaminidase assays on crude extracts of vitreous revealed granules and granule secretions from polymorphonuclear cells with levels according the above classification. These results show that channel-forming leucotoxins have a very significant inflammatory activity. As most S. aureus strains produce two or even six leucotoxins depending on the production of Panton-Valentine leucocidin, these compounds could be considered to be virulence factors.

Topics: Acetylglucosaminidase; Animals; Bacterial Proteins; Bacterial Toxins; Dose-Response Relationship, Drug; Exotoxins; Eye; Hemolysin Proteins; Inflammation; Leukocidins; Rabbits; Staphylococcus aureus; Time Factors