Anti-Leishmania effect of icetexanes from Salvia procurrens.

BACKGROUND AND PURPOSE: Leishmaniasis is a globally prevalent vector-borne disease caused by parasites of the genus Leishmania. The available chemotherapeutic drugs present problems related to efficacy, emergence of parasite resistance, toxicity and high cost, justifying the search for new drugs. Several classes of compounds have demonstrated activity against Leishmania, including icetexane-type diterpenes, previously isolated from Salvia and other Lamiaceae genera. Thus, in this study, compounds of Salvia procurrens were investigated for their leishmanicidal and immunomodulatory activities. METHODS: The exudate of S. procurrens was obtained by rapidly dipping the aerial parts in dichloromethane. The compounds were isolated by column and centrifugal planar chromatography over silica gel. The effects on L. amazonensis growth, survival, membrane integrity, reactive oxygen species (ROS) generation, mitochondrial membrane potential and cytotoxicity of the compounds towards human erythrocytes, peripheral blood mononuclear cells and macrophages were evaluated. The effects on intracellular amastigote forms, nitric oxide (NO) and TNF-α production were also investigated. RESULTS: The exudate from the leaves afforded the novel icetexane 7-hydroxyfruticulin A (1) as well as the known demethylisofruticulin A (2), fruticulin A (3) and demethylfruticulin A (4). The compounds (1-4) were tested against promastigotes of L. amazonensis and showed an effective inhibition of the parasite survival (IC50 = 4.08-16.26 µM). In addition, they also induced mitochondrial ROS production, plasma membrane permeability and mitochondrial dysfunction in treated parasites, and presented low cytotoxicity against macrophages. Furthermore, all diterpenes tested reduced the number of parasites inside macrophages, by mechanisms involving TNF-α, NO and ROS. CONCLUSION: The results suggest the potential of 7-hydroxyfruticulin A (1) as well as the known demethylisofruticulin A (2),fruticulin A (3) and demethylfruticulin A (4) as candidates for use in further studies on the design of anti-leishmanial drugs.

Differential effects of whole blood heat treatment on the ex vivo inflammatory profile of untrained and trained men.

This study evaluated the effects of heat stress on the ex vivo inflammatory profile in untrained and trained men. Whole blood samples from untrained (UT) and trained (TR) individuals were incubated for 2 h at 37 °C or 40 °C. The whole blood of a subsample of the participants (n = 5 in both TR and UT groups) were stimulated with lipopolysaccharide (LPS, 10 ng/mL) concomitant to heat treatment (37 °C versus 40 °C). Flow cytometry was used to assess the intracellular NF-κB activation in CD4+ T cells and CD14+ monocytes, the expression of Toll-Like Receptor-4 (TLR-4), the frequencies of CD4+CD25-CD39+ and CD4+CD25+CD39+ T cells and monocyte subsets (CD14+CD16-; CD14+CD16+; CD14-CD16+), the mitochondrial membrane potential (MMP) and the reactive oxygen species (ROS) production by lymphocytes and monocytes. The production of interleukin (IL)-6, IL-10, and tumor necrosis factor-alpha (TNF-α) by LPS-stimulated whole blood were also evaluated. Heat treatment (40 °C) increased the proportions of CD14+CD16- and CD14+CD16+ monocytes and the lymphocyte MMP in the UT group. The frequencies of CD14-CD16+ monocytes and the activation of NF-κB in CD14+ monocytes decreased in UT and TR groups after heat treatment, while a reduction in CD4+CD25-CD39+ T-cells was observed only in the UT group. Higher TLR-4 and NF-κB activation were found in LPS-stimulated monocytes of UT men concomitant with higher TNF-α production and diminished IL-10 production after heat treatment. TR individuals presented lower NF- κB activation in LPS-stimulated monocytes after heat treatment. Our data suggest that the training status of individuals may impact on the anti-inflammatory response of heat treatment.

New Insights about Regulatory T Cells Distribution and Function with Exercise: The Role of Immunometabolism.

A lack of physical activity is linked to the development of many chronic diseases through a chronic low-grade inflammation state. It is now well accepted that the immune system plays a central role in the development of several chronic diseases, including insulin resistance, type 2 diabetes, atherosclerosis, heart failure and certain types of cancer. Exercise elicits a strong anti-inflammatory response independently of weight loss and can be a useful non-pharmacologic strategy to counteract the low-grade inflammation. The CD4+CD25+CD127- FoxP3+ Regulatory T (Treg) cells are a unique subset of helper T-cells, which regulate immune response and establish self-tolerance through the secretion of immunoregulatory cytokines, such as IL-10 and TGF-ß, and the suppression of the function and activity of many immune effector cells (including monocytes/macrophages, dendritic cells, CD4+ and CD8+ T cells, and Natural Killers). The metabolic phenotype of Tregs are regulated by the transcription factor Foxp3, providing flexibility in fuel choice, but a preference for higher fatty acid oxidation. In this review, we focus on the mechanisms by which exercise - both acute and chronic - exerts its antiinflammatory effects through Treg cells mobilization. Furthermore, we discuss the implications of immunometabolic changes during exercise for the modulation of Treg phenotype and its immunosuppressive function. This narrative review focuses on the current knowledge regarding the role of Treg cells in the context of acute and chronic exercise using data from observational and experimental studies. Emerging evidence suggests that the immunomodulatory effects of exercise are mediated by the ability of exercise to adjust and improve Tregs number and function.

Radiation effects on Toxoplasma antigens: different immune responses of irradiated intact tachyzoites or soluble antigens in experimental mice models.

Purpose: Purpose: Protein irradiation causes aggregation, chain breakage, and oxidation, enhancing its uptake by antigen-presenting cells. To evaluate if irradiated proteins participate on the protection, we studied the immune response induced in mice immunized with irradiated soluble extracts of T. gondii tachyzoites (STag) or irradiated intact T. gondii RH tachyzoites (RH0.25 kGy).Material and Methods: Soluble extracts of Toxoplasma gondii tachyzoites (STag) were irradiated at different dose by Cobalt-60 source. By polyacrylamide gel electrophoresis (SDS-Page) we evaluated the effects on primary structures of protein STags induced by irradiation. By Enzyme-linked Immunosorbent Assay (ELISA) we evaluated the difference between humoral immune response induced by irradiated STag or RH tachyzoites in immunized mice from the detection of specific immunoglobulin G (IgG) antibodies in the serum of immunized mice. From challenge with viable RH strain of T. gondii we evaluated the protection induced in the immunized animals. By cytometry we performed the phenotyping of T and B lymphocytes in the peripheral blood of the immunized animals.Results: Irradiation dose of 1.5 kGy induced minimal changes in most proteins, without affecting their antigenicity or immunogenicity. Immunization showed saturation at the dose of 10 µg/mice, with worst response at higher doses. STag irradiated at 1.5 kGy (STag1.5 kGy) induced higher survival and protection similar to T. gondii RH strain irradiated at 0.25 kGy (RH0.25 kGy), with higher serum levels of high affinity IgG compared to STag native. Blood immune memory cells of mice immunized with STag1.5 kGy had higher proportions of CD19+ (cluster of differentiation 19) and CD4+ (cluster of differentiation 14) cells, whereas mice RH0.25 kGy had high proportion of memory CD8+ (cluster of differentiation 8) cells.Conclusions: Our data suggest that major histocompatibility complex type I (MHCI) pathway, appears seem to be used by RH0.25 kGy to generate cytotoxic cells while STag1.5 kGy uses a major histocompatibility complex type II (MHCII) pathway for B-cell memory, but both induce sufficient immune response for protection in mice without any adjuvant. Irradiation of soluble protein extracts enhances their immune response, allowing similar protection against T. gondii in mice as compared to irradiated intact parasites.