56 research outputs found

    IL-17 Produced during Trypanosoma cruzi Infection Plays a Central Role in Regulating Parasite-Induced Myocarditis

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    Chagas disease is caused by the intracellular parasite Trypanosoma cruzi. This infection has been considered one of the most neglected diseases and affects several million people in the Central and South America. Around 30% of the infected patients develop digestive and cardiac forms of the disease. Most patients are diagnosed during the chronic phase, when the treatment is not effective. Here, we showed by the first time that IL-17 is produced during experimental T. cruzi infection and that it plays a significant role in host defense, modulating parasite-induced myocarditis. Applying this analysis to humans could be of great value in unraveling the elements involved in the pathogenesis of chagasic cardiopathy and could be used in the development of alternative therapies to reduce morbidity during the chronic phase of the disease, as well as clinical markers of disease progression. The understanding of these aspects of disease may be helpful in reducing the disability-adjusted life years (DALYs) and costs to the public health service in developing countries

    Regulated Nuclear Trafficking of rpL10A Mediated by NIK1 Represents a Defense Strategy of Plant Cells against Virus

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    The NSP-interacting kinase (NIK) receptor-mediated defense pathway has been identified recently as a virulence target of the geminivirus nuclear shuttle protein (NSP). However, the NIK1–NSP interaction does not fit into the elicitor–receptor model of resistance, and hence the molecular mechanism that links this antiviral response to receptor activation remains obscure. Here, we identified a ribosomal protein, rpL10A, as a specific partner and substrate of NIK1 that functions as an immediate downstream effector of NIK1-mediated response. Phosphorylation of cytosolic rpL10A by NIK1 redirects the protein to the nucleus where it may act to modulate viral infection. While ectopic expression of normal NIK1 or a hyperactive NIK1 mutant promotes the accumulation of phosphorylated rpL10A within the nuclei, an inactive NIK1 mutant fails to redirect the protein to the nuclei of co-transfected cells. Likewise, a mutant rpL10A defective for NIK1 phosphorylation is not redirected to the nucleus. Furthermore, loss of rpL10A function enhances susceptibility to geminivirus infection, resembling the phenotype of nik1 null alleles. We also provide evidence that geminivirus infection directly interferes with NIK1-mediated nuclear relocalization of rpL10A as a counterdefensive measure. However, the NIK1-mediated defense signaling neither activates RNA silencing nor promotes a hypersensitive response but inhibits plant growth and development. Although the virulence function of the particular geminivirus NSP studied here overcomes this layer of defense in Arabidopsis, the NIK1-mediated signaling response may be involved in restricting the host range of other viruses

    Differential Regional Immune Response in Chagas Disease

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    Following infection, lymphocytes expand exponentially and differentiate into effector cells to control infection and coordinate the multiple effector arms of the immune response. Soon after this expansion, the majority of antigen-specific lymphocytes die, thus keeping homeostasis, and a small pool of memory cells develops, providing long-term immunity to subsequent reinfection. The extent of infection and rate of pathogen clearance are thought to determine both the magnitude of cell expansion and the homeostatic contraction to a stable number of memory cells. This straight correlation between the kinetics of T cell response and the dynamics of lymphoid tissue cell numbers is a constant feature in acute infections yielded by pathogens that are cleared during the course of response. However, the regional dynamics of the immune response mounted against pathogens that are able to establish a persistent infection remain poorly understood. Herein we discuss the differential lymphocyte dynamics in distinct central and peripheral lymphoid organs following acute infection by Trypanosoma cruzi, the causative agent of Chagas disease. While the thymus and mesenteric lymph nodes undergo a severe atrophy with massive lymphocyte depletion, the spleen and subcutaneous lymph nodes expand due to T and B cell activation/proliferation. These events are regulated by cytokines, as well as parasite-derived moieties. In this regard, identifying the molecular mechanisms underlying regional lymphocyte dynamics secondary to T. cruzi infection may hopefully contribute to the design of novel immune intervention strategies to control pathology in this infection

    The effects of nitric oxide on the immune system during Trypanosoma cruzi infection

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    Back to the future in Chagas disease: from animal models to patient cohort studies, progress in immunopathogenesis research

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    International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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    Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

    Adhesion and invasion of Candida albicans from periodontal pockets of patients with chronic periodontitis and diabetes to gingival human fibroblasts

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    The objectives of this study were to evaluate clinical isolates of Candida albicans, particularly their adhesion to and invasion of gingival human fibroblasts in culture and to measure nitric oxide concentration (NO) produced by fibroblasts in the presence of these yeasts. Sixteen strains of C. albicans isolated from patients with chronic periodontitis and diabetes mellitus type II were divided on the basis of phenotypic tests into two groups, i.e., highly or weakly hydrophobic. Primary cultures of human fibroblasts were isolated from gingival biopsies and after subsequent subcultures, the cells were seeded into culture plates and incubated for 24 h. C. albicans strains were inoculated into these plates and maintained for 2 and 4 h to assess their adhesion and invasion, respectively. The number of adherent or invasive yeasts was evaluated by assessing colony-forming units (CFU). The production of NO by fibroblasts was also quantified. The results showed that strains with high hydrophobicity had a greater ability to adhere and invade fibroblasts (p < 0.05, ANOVA and Tukey). The production of NO was higher for the most hydrophobic strains, but did not reach statistical difference with the weakly hydrophobic isolates. These data indicated that the hydrophobicity may play a role in the adhesion and invasion of C. albicans in fibroblast cultures.501434

    Levels of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, inflammatory cytokines and species-specific immunoglobulin G in generalized aggressive and chronic periodontitis

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Background and Objective: Aggressive periodontitis pathogenesis still is not completely understood in the literature regarding the relationship between microbial and inflammatory aspects. So this study aimed to compare microbial and inflammatory patterns in the gingival crevicular fluid of generalized aggressive and chronic periodontitis patients. Material and Methods: Forty aggressive and 28 chronic periodontitis patients were selected. Biofilm and gingival crevicular fluid were collected from a deep pocket (periodontal probing depth > 7 mm) and a moderate pocket (periodontal probing depth = 5 mm) of each patient, and microbiological and immunoenzymatic assays were performed. Real-time PCR was used to determine quantities of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Enzyme-linked immunosorbent assay (ELISA) was employed to determine gingival crevicular fluid levels of interleukin-1 beta, interferon-gamma, prostaglandin E(2) and interleukin-10. In addition, immunoglobulin G (IgG) levels against A. actinomycetemcomitans and P. gingivalis lipopolysaccharide were also determined by ELISA. Analysis of variance/Tukey test, Mann-Whitney U-test and the Pearson correlation test were used to determine differences and correlations between variables analysed (alpha = 5%). Results: Patients suffering from generalized aggressive periodontitis had their mouth colonized by higher amounts of A. actinomycetemcomitans and P. gingivalis than chronic periodontitis patients. Conversely, the gingival crevicular fluid levels of IgG against both pathogens were statistically inferior in aggressive periodontitis patients (p < 0.05). With regard to gingival crevicular fluid levels of cytokines, aggressive periodontitis patients presented reduced levels of interleukin-10 (p < 0.05). Conclusion: In comparison to chronic periodontitis, generalized aggressive periodontitis patients have an imbalance in the host response, with reduced levels of interleukin-10 and IgG, and increased periodontal pathogens.455635642Fond Emile-Beaulieu [93129]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fond Emile-Beaulieu [93129]FAPESP [06/60314-5
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