Methyl gallate nanomicelles impairs neutrophil accumulated in zymosan-induced arthritis.

Arthritis is a chronic disease that affects, approximately, 1 % of the total global population. It is characterized by chronic inflammation, accompanied in most of the cases of motor disability and sever pain. The main therapies available have high risk of failure and advanced treatments are scarce and highly cost. In this scenario, search for effective, safe and low-cost treatments is quite desirable. Methyl gallate (MG) is a plant-derived phenolic compound described to present remarkable anti-inflammatory effect in experimental models of arthritis. Thus, in this study we formulated nanomicelles of MG using Pluronic (F-127) as matrix and evaluated in vivo the pharmacokinetic, biodistribution and its effect in the mice model of zymosan-induced arthritis. The nanomicelles were formed with a size 126 nm. The biodistribution showed a ubiquitous tissue deposition with a renal excretion. The pharmacokinetics showed elimination half-life of 1.72 h and a clearance of 0.006 L/h. The oral pretreatment with nanomicelles containing MG (3.5 or 7 mg/kg) demonstrated a reduction in total leukocytes, neutrophils, and mononuclear cells from the inflammation site. The data supports the use of methyl gallate nanomicelles as an alternative drug for arthritis. DATA AVAILABILITY: All the data of this study are transparent.

Nanoparticle conjugated with aptamer anti-MUC1/Y for inflammatory arthritis.

Aptamers may form well-defined three-dimensional structures binding with high affinity and stability to a specific receptor. The aptamer anti-MUC1 isoform Y is one the most used due the affinity to MUC1, which is overexpressed in several types of cancer and inflammation process. In this study we have developed, characterized, in vitro as in vivo evaluated a nanoaptamer (anti-MUC1/Y) as a nanoagent for rheumatoid arthritis treatment. The results showed that a nanoaptamer with a size range of 241 nm was produced. The entrapment efficacy was 90% with a biodistribution showing a high hepatic uptake (>98%). The results in vivo showed a potent effect in arthritis experimental model, especially in low doses. The results corroborate the applicability of this nanosystem for RA treatment.

Anti-Inflammatory Activity and Chemical Analysis of Different Fractions from Solidago chilensis Inflorescence.

Solidago chilensis Meyen (Compositae) is a species native to South America (Brazil) popularly known as arnica. In Brazilian popular medicine, inflorescences and rhizomes of this plant have been used since the end of the 19th century to replace the exogenous and hepatotoxic Arnica montana L. in the treatment of edema and inflammatory pathologies. Although the anti-inflammatory activity of S. chilensis is evidenced in the literature, there is a lack of studies with enriched fractions or compounds isolated from it. The objective of the current study was to characterize phytochemically and to evaluate the pharmacological action in vivo and in vitro of the crude extract and the different fractions (hexane, dichloromethane, acetal, butanolic, and aqueous) isolated from the inflorescence of S. chilensis. The inflorescence crude extract (ScIE) and fractions were administered by intraperitoneal route to mice at different doses. In an LPS-induced pleurisy model, inhibition of leukocyte influx was observed for the ScIE and all fractions tested, as compared to controls. Dichloromethane (ScDicF), butanolic (ScButF), and aqueous (ScAquF) were selected for further analysis as they showed the best inhibitory effects in leukocyte migration and inflammatory cytokine and chemokine production: TNF-α, CXCL1/KC, CXCL2/MIP-2, and CCL11/eotaxin-1. In LPS-stimulated J774A.1 cell line, ScIE and the ScDicF exhibited an inhibitory effect on nitric oxide (NO) production and downmodulated the COX-2 expression; ScAquF failed to modulate NO production and COX-2 expression. In phytochemical analysis, HPLC-UV-DAD chromatograms of ScDicF and ScAquF showed the main peaks with UV spectrum characteristics of flavonoids; chlorogenic acid and isoquercetin were the most present phytochemicals identified in the ScAquF, and a high number of n-alkanes was found in ScHexF. Our study was the first to address biological effects and correlate them to phytochemically characterized fractions from inflorescences of S. chilensis.

Intra-articular use of radium dichloride ([223Ra] RaCl2) showed relevant anti-inflammatory response on experimental arthritis model.

Rheumatoid arthritis (RA) is an inflammatory chronic autoimmune disease. The treatment of RA is difficult and, in many cases, ineffective, and the arsenal of drugs is limited. Due the longevity of the disease, RA may cause extreme musculoskeletal disorders with a high impact on quality of life. Also, RA is related with severe comorbidities decreasing the life expectancy. Finally, RA has been reported to impact in economy and healthy public. In this direction, the necessity to discover new strategies to efficiently treat RA is immediate. In this direction, we have reported the use of low doses of [223Ra] RaCl2 (radium dichloride) as intra-articular injection to treat RA. Mice were post-treated with [223Ra] RaCl2 (1.48 µCi; i.a.) 24 h after zymosan stimulus. Zymosan-induced arthrithis is responsible for leucocyte recruitment (total leukocytes, neutrophils, and mononuclear cells), which were inhibited by intra-articular injection of [223Ra] RaCl2 (69%, 77%, and 66%, respectively).

Rheumatoid arthritis treatment using hydroxychloroquine and methotrexate co-loaded nanomicelles: In vivo results.

Rheumatoid arthritis (RA) is the most common inflammatory rheumatic disease, affecting almost 1% of the world population. It is a long-lasting autoimmune disease, which mainly affects the joints causing inflammation and swelling of the synovial joint. RA has a significant impact on the ability to perform daily activities including simple work and household chores. Nonetheless, due to the long periods of pain and the continuous use of anti-inflammatory drugs, RA can debilitate the quality of life and increases mortality. Current therapeutic approaches to treat RA aim to achieve prolonged activity and early and persistent remission of the disease, with the gradual adoption of different drugs available. In this study, we developed a novel hydroxychloroquine and methotrexate co-loaded Pluronic® F-127 nanomicelle and evaluated its therapeutic effects against RA. Our results showed that drug-loaded nanomicelles were capable of modulating the inflammatory process of RA and reducing osteoclastogenesis, edema, and cell migration to the joint. Overall, compared to the free drugs, the drug-loaded nanomicelles showed a 2-fold higher therapeutic effect.

IL-4 Receptor α Chain Protects the Kidney Against Tubule-Interstitial Injury Induced by Albumin Overload.

Increasing evidence has highlighted the role of tubule-interstitial injury (TII) as a vital step in the pathogenesis of acute kidney injury (AKI). Incomplete repair of TII during AKI could lead to the development of chronic kidney disease. Changes in albumin endocytosis in proximal tubule epithelial cells (PTECs) is linked to the development of TII. In this context, interleukin (IL)-4 has been shown to be an important factor in modulating recovery of TII. We have studied the possible role of IL-4 in TII induced by albumin overload. A subclinical AKI model characterized by albumin overload in the proximal tubule was used, without changing glomerular function. Four groups were generated: (1) CONT, wild-type mice treated with saline; (2) BSA, wild-type mice treated with 10 g/kg/day bovine serum albumin (BSA); (3) KO, IL4Rα-/- mice treated with saline; and (4) KO + BSA, IL4Rα-/- mice treated with BSA. As reported previously, mice in the BSA group developed TII without changes in glomerular function. The following parameters were increased in the KO + BSA group compared with the BSA group: (1) tubular injury score; (2) urinary γ-glutamyltransferase; (3) CD4+ T cells, dendritic cells, macrophages, and neutrophils are associated with increases in renal IL-6, IL-17, and transforming growth factor ß. A decrease in M2-subtype macrophages associated with a decrease in collagen deposition was observed. Using LLC-PK1 cells, a model of PTECs, we observed that (1) these cells express IL-4 receptor α chain associated with activation of the JAK3/STAT6 pathway; (2) IL-4 alone did not change albumin endocytosis but did reverse the inhibitory effect of higher albumin concentration. This effect was abolished by JAK3 inhibitor. A further increase in urinary protein and creatinine levels was observed in the KO + BSA group compared with the BSA group, but not compared with the CONT group. These observations indicate that IL-4 has a protective role in the development of TII induced by albumin overload that is correlated with modulation of the pro-inflammatory response. We propose that megalin-mediated albumin endocytosis in PTECs could work as a sensor, transducer, and target during the genesis of TII.

Immunogenicity of synthetic peptide constructs based on PvMSP9E795-A808, a linear B-cell epitope of the P. vivax Merozoite Surface Protein-9.

Plasmodium vivax Merozoite Surface Protein-9 (PvMSP-9) is a malaria vaccine candidate naturally immunogenic in humans and able to induce high antibody titers in animals when delivered as a recombinant protein. Recently, we identified the sequence EAAPENAEPVHENA (PvMSP9E795-A808) as the main linear B-cell epitope in naturally exposed individuals. However, the potential of PvMSP9E795-A808 as an immunogen in experimental animal models remained unexplored. Here we assess the immunogenicity of PvMSP9E795-A808 using synthetic peptides. The peptides tested in BALB/c mice include two repeats of the sequence EAAPENAEPVHENA tested alone (peptide RII), or linked to an autologous (PvMSP9 peptide pL; pLRII) or heterologous (p2 tetanus toxin universal T cell epitope; TTRII) T cell epitope. Immune responses were evaluated by ELISA, FLUOROSPOT, and indirect immunofluorescence. We show that all of the peptide constructs tested were immunogenic eliciting specific IgG antibodies at different levels, with a prevalence of IgG1 and IgG2. Animals immunized with synthetic peptides containing T cell epitopes (pLRII or TTRII) had more efficient antibody responses that resulted in higher antibody titers able to recognize the native protein by immunofluorescence. Relevantly, the frequency of IFN-γ secreting SFC elicited by immunization with TTRII synthetic peptide was comparable to that reported to the PvMSP9-Nt recombinant protein. Taken together, our study indicates that PvMSP9E795-A808 is highly immunogenic in mice and further studies to evaluate its value as promising vaccine target are warranted. Moreover, our study supports the critical role of CD4 T cell epitopes to enhance humoral responses induced by subunit based vaccines.

Exposure to the UV Filter Octyl Methoxy Cinnamate in the Postnatal Period Induces Thyroid Dysregulation and Perturbs the Immune System of Mice.

Evidence demonstrates the bidirectional communication and regulation between the neuroendocrine and immune systems. Thyroid hormones play key roles in nervous system development and can exert influence on various immune cells contributing to pathophysiological conditions. Octyl methoxycinnamate (OMC) is one of the most commonly used UV filters, and in vitro and in vivo studies have found thyroid disrupting effects. The present study assessed whether OMC administration in mice dams during the lactational period can cause thyroid disruption and generate immunologic alterations in the offspring. Indirect exposure to the OMC (1,000 mg/kg) in the lactational period affected neurodevelopment parameters, such as delayed eye-opening and weight gain in mice of both sexes, and these alterations are corroborated by the decrease in the T4 levels present in the pups' blood. No significant changes were observed in the thymus of these pups, but the number of lymphocytes increased in the spleen of the animals exposed to OMC, similar to the animals treated with propyl-thiouracil (PTU), a well-known thyroid disruptor. OMC modulated the percentage of leukocyte populations in peripheral blood, and the number of circulating polymorphonuclear cells increased two-fold. In vitro, OMC exhibited an inhibitory effect on splenocyte proliferation and IL-2 production induced by anti-CD3 antibody; however, this effect was reversed with the addition of T4 in the cell culture. In summary, the results of the present study demonstrate the influence of OMC on thyroid dysregulation and its impact on the modulation of the immune system in mice pups.

LPS Induces mTORC1 and mTORC2 Activation During Monocyte Adhesion.

Monocyte adhesion is a crucial step in transmigration and can be induced by lipopolysaccharide (LPS). Here, we studied the role of mammalian target of rapamycin (mTOR) complexes, mTORC1 and mTORC2, and PKC in this process. We used THP-1 cells, a human monocytic cell line, to investigate monocyte adhesion under static and flow conditions. We observed that 1.0 µg/mL LPS increased PI3K/mTORC2 pathway and PKC activity after 1 h of incubation. WYE-354 10-6 M (mTORC2/mTORC1 inhibitor) and 10-6 M wortmannin avoided monocyte adhesion in culture plates. In addition, WYE also blocked LPS-induced CD11a expression. Interestingly, rapamycin and WYE-354 blocked both LPS-induced monocyte adhesion in a cell monolayer and actin cytoskeleton rearrangement, confirming mTORC1 involvement in this process. Once activated, PKC activates mTORC1/S6K pathway in a similar effect observed to LPS. Activation of the mTORC1/S6K pathway was attenuated by 10-6 M U0126, an MEK/ERK inhibitor, and 10-6 M calphostin C, a PKC inhibitor, indicating that the MEK/ERK/TSC2 axis acts as a mediator. In agreement, 80 nM PMA (a PKC activator) mimicked the effect of LPS on the activation of the MEK/ERK/TSC2/mTORC1/S6K pathway, monocyte adhesion to ECV cells and actin cytoskeleton rearrangement. Our findings show that LPS induces activation of mTOR complexes. This signaling pathway led to integrin expression and cytoskeleton rearrangement resulting in monocyte adhesion. These results describe a new molecular mechanism involved in monocyte adhesion in immune-based diseases.

Gedunin Binds to Myeloid Differentiation Protein 2 and Impairs Lipopolysaccharide-Induced Toll-Like Receptor 4 Signaling in Macrophages.

Recognition of bacterial lipopolysaccharide (LPS) by innate immune system is mediated by the cluster of differentiation 14/Toll-like receptor 4/myeloid differentiation protein 2 (MD-2) complex. In this study, we investigated the modulatory effect of gedunin, a limonoid from species of the Meliaceae family described as a heat shock protein Hsp90 inhibitor, on LPS-induced response in immortalized murine macrophages. The pretreatment of wild-type (WT) macrophages with gedunin (0.01-100 µM, noncytotoxic concentrations) inhibited LPS (50 ng/ml)-induced calcium influx, tumor necrosis factor-α, and nitric oxide production in a concentration-dependent manner. The selective effect of gedunin on MyD88-adapter-like/myeloid differentiation primary response 88- and TRIF-related adaptor molecule/TIR domain-containing adapter-inducing interferon-ß-dependent signaling pathways was further investigated. The pretreatment of WT, TIR domain-containing adapter-inducing interferon-ß knockout, and MyD88 adapter-like knockout macrophages with gedunin (10 µM) significantly inhibited LPS (50 ng/ml)-induced tumor necrosis factor-α and interleukin-6 production, at 6 hours and 24 hours, suggesting that gedunin modulates a common event between both signaling pathways. Furthermore, gedunin (10 µM) inhibited LPS-induced prostaglandin E2 production, cyclooxygenase-2 expression, and nuclear factor κB translocation into the nucleus of WT macrophages, demonstrating a wide-range effect of this chemical compound. In addition to the ability to inhibit LPS-induced proinflammatory mediators, gedunin also triggered anti-inflammatory factors interleukin-10, heme oxygenase-1, and Hsp70 in macrophages stimulated or not with LPS. In silico modeling studies revealed that gedunin efficiently docked into the MD-2 LPS binding site, a phenomenon further confirmed by surface plasmon resonance. Our results reveal that, in addition to Hsp90 modulation, gedunin acts as a competitive inhibitor of LPS, blocking the formation of the Toll-like receptor 4/MD-2/LPS complex.

Murine IL-17+ Vγ4 T lymphocytes accumulate in the lungs and play a protective role during severe sepsis.

BACKGROUND: Lung inflammation is a major consequence of the systemic inflammatory response caused by severe sepsis. Increased migration of γδ T lymphocytes into the lungs has been previously demonstrated during experimental sepsis; however, the involvement of the γδ T cell subtype Vγ4 has not been previously described. METHODS: Severe sepsis was induced by cecal ligation and puncture (CLP; 9 punctures, 21G needle) in male C57BL/6 mice. γδ and Vγ4 T lymphocyte depletion was performed by 3A10 and UC3-10A6 mAb i.p. administration, respectively. Lung infiltrating T lymphocytes, IL-17 production and mortality rate were evaluated. RESULTS: Severe sepsis induced by CLP in C57BL/6 mice led to an intense lung inflammatory response, marked by the accumulation of γδ T lymphocytes (comprising the Vγ4 subtype). γδ T lymphocytes present in the lungs of CLP mice were likely to be originated from peripheral lymphoid organs and migrated towards CCL2, CCL3 and CCL5, which were highly produced in response to CLP-induced sepsis. Increased expression of CD25 by Vγ4 T lymphocytes was observed in spleen earlier than that by αß T cells, suggesting the early activation of Vγ4 T cells. The Vγ4 T lymphocyte subset predominated among the IL-17(+) cell populations present in the lungs of CLP mice (unlike Vγ1 and αß T lymphocytes) and was strongly biased toward IL-17 rather than toward IFN-γ production. Accordingly, the in vivo administration of anti-Vγ4 mAb abrogated CLP-induced IL-17 production in mouse lungs. Furthermore, anti-Vγ4 mAb treatment accelerated mortality rate in severe septic mice, demonstrating that Vγ4 T lymphocyte play a beneficial role in host defense. CONCLUSIONS: Overall, our findings provide evidence that early-activated Vγ4 T lymphocytes are the main responsible cells for IL-17 production in inflamed lungs during the course of sepsis and delay mortality of septic mice.

Study of the antimalarial properties of hydroxyethylamine derivatives using green fluorescent protein transformed Plasmodium berghei

A rapid decrease in parasitaemia remains the major goal for new antimalarial drugs and thus, in vivo models must provide precise results concerning parasitaemia modulation. Hydroxyethylamine comprise an important group of alkanolamine compounds that exhibit pharmacological properties as proteases inhibitors that has already been proposed as a new class of antimalarial drugs. Herein, it was tested the antimalarial property of new nine different hydroxyethylamine derivatives using the green fluorescent protein (GFP)-expressing Plasmodium berghei strain. By comparing flow cytometry and microscopic analysis to evaluate parasitaemia recrudescence, it was observed that flow cytometry was a more sensitive methodology. The nine hydroxyethylamine derivatives were obtained by inserting one of the following radical in the para position: H, 4Cl, 4-Br, 4-F, 4-CH3, 4-OCH3, 4-NO2, 4-NH2 and 3-Br. The antimalarial test showed that the compound that received the methyl group (4-CH3) inhibited 70% of parasite growth. Our results suggest that GFP-transfected P. berghei is a useful tool to study the recrudescence of novel antimalarial drugs through parasitaemia examination by flow cytometry. Furthermore, it was demonstrated that the insertion of a methyl group at the para position of the sulfonamide ring appears to be critical for the antimalarial activity of this class of compounds.

Study of the antimalarial properties of hydroxyethylamine derivatives using green fluorescent protein transformed Plasmodium berghei.

A rapid decrease in parasitaemia remains the major goal for new antimalarial drugs and thus, in vivo models must provide precise results concerning parasitaemia modulation. Hydroxyethylamine comprise an important group of alkanolamine compounds that exhibit pharmacological properties as proteases inhibitors that has already been proposed as a new class of antimalarial drugs. Herein, it was tested the antimalarial property of new nine different hydroxyethylamine derivatives using the green fluorescent protein (GFP)-expressing Plasmodium berghei strain. By comparing flow cytometry and microscopic analysis to evaluate parasitaemia recrudescence, it was observed that flow cytometry was a more sensitive methodology. The nine hydroxyethylamine derivatives were obtained by inserting one of the following radical in the para position: H, 4Cl, 4-Br, 4-F, 4-CH3, 4-OCH3, 4-NO2, 4-NH2 and 3-Br. The antimalarial test showed that the compound that received the methyl group (4-CH3) inhibited 70% of parasite growth. Our results suggest that GFP-transfected P. berghei is a useful tool to study the recrudescence of novel antimalarial drugs through parasitaemia examination by flow cytometry. Furthermore, it was demonstrated that the insertion of a methyl group at the para position of the sulfonamide ring appears to be critical for the antimalarial activity of this class of compounds.

Anti-inflammatory effects of methyl ursolate obtained from a chemically derived crude extract of apple peels: potential use in rheumatoid arthritis.

Ursolic acid (UA), a pentacyclic triterpene acid found in apple peels (Malus domestica, Borkh, Rosaceae), has a large spectrum of pharmacological effects. However, the vegetal matrix usually produces highly viscous and poorly soluble extracts that hamper the isolation of this compound. To overcome this problem, the crude EtOH-AcOEt extract of commercial apple peels was exhaustively treated with diazomethane, after which methyl ursolate (MU) was purified by column chromatography and characterized spectrometrically. The anti-inflammatory effects of UA and MU (50 mg/kg) were analyzed by zymosan-induced paw edema, pleurisy and in an experimental arthritis model. After 4 h of treatment with UA and MU, paw edema was reduced by 46 and 44 %, respectively. Both UA and MU inhibited protein extravasation into the thoracic cavity; tibio-femoral edema by 40 and 48 %, respectively; and leukocyte influx into the synovial cavity after 6 h by 52 and 73 %, respectively. Additionally, both UA and MU decreased the levels of mediators related to synovial inflammation, such as KC/CXCL-1 levels by 95 and 90 %, TNF-α levels by 76 and 71 %, and IL-1ß levels by 57 and 53 %, respectively. Both the compounds were equally effective when assayed in different inflammatory models, including experimental arthritis. Hence, MU may be considered to be a useful anti-inflammatory derivative to overcome the inherent poor solubility of UA for formulating pharmaceutical products.

The therapeutic properties of Carapa guianensis.

Carapa guianensis Aublet (Meliaceae), also known as andiroba, is used in popular medicine in Brazil and other countries encompassing the Amazon rainforest. Virtually all parts of the andiroba tree are utilized, including the seed's oil, which is employed to treat inflammation and infections. The medicinal properties of C. guianensis have been attributed to the presence of limonoids, which are tetranortriterpenoids. We have previously demonstrated that the oil obtained from C. guianensis seeds contains different tetranortriterpenoids, including 6α-acetoxygedunin, 7-deacetoxy-7-oxogedunin, andirobin, gedunin and methyl-angolensate. The seeds oil and this fraction of tetranortriterpenoids present marked anti-inflammatory and anti-allergic properties, by inhibiting edema formation in different experimental models in rodents, via the impairment of signaling pathways triggered by histamine, bradykinin and platelet-activating factor. Tetranortriterpenoids also impaired the production of inflammatory mediators that trigger leukocyte infiltration into the inflammatory site, including the eosinophilotactic mediators interleukin (IL)-5 and CCL11/eotaxin, as well as the inflammatory cytokines tumor necrosis factor (TNF)-α and IL-1ß. This phenomenon seems to depend on the inhibition of nuclear factor κB (NFκB) activation. We have further demonstrated that each one of the five tetranortriterpenoids listed above presented inhibitory effects on the activation of different cell populations, including mast cells, eosinophils and T lymphocytes, through which they impaired allergy and inflammation. This review will discuss the therapeutic effects of C. guianensis oil and its compounds, focusing on the scientific evidences that support its traditional use in inflammatory conditions and its anti-allergic properties.

Metabonomics reveals drastic changes in anti-inflammatory/pro-resolving polyunsaturated fatty acids-derived lipid mediators in leprosy disease.

Despite considerable efforts over the last decades, our understanding of leprosy pathogenesis remains limited. The complex interplay between pathogens and hosts has profound effects on host metabolism. To explore the metabolic perturbations associated with leprosy, we analyzed the serum metabolome of leprosy patients. Samples collected from lepromatous and tuberculoid patients before and immediately after the conclusion of multidrug therapy (MDT) were subjected to high-throughput metabolic profiling. Our results show marked metabolic alterations during leprosy that subside at the conclusion of MDT. Pathways showing the highest modulation were related to polyunsaturated fatty acid (PUFA) metabolism, with emphasis on anti-inflammatory, pro-resolving omega-3 fatty acids. These results were confirmed by eicosanoid measurements through enzyme-linked immunoassays. Corroborating the repertoire of metabolites altered in sera, metabonomic analysis of skin specimens revealed alterations in the levels of lipids derived from lipase activity, including PUFAs, suggesting a high lipid turnover in highly-infected lesions. Our data suggest that omega-6 and omega-3, PUFA-derived, pro-resolving lipid mediators contribute to reduced tissue damage irrespectively of pathogen burden during leprosy disease. Our results demonstrate the utility of a comprehensive metabonomic approach for identifying potential contributors to disease pathology that may facilitate the development of more targeted treatments for leprosy and other inflammatory diseases.

Angiotensin II is a new component involved in splenic T lymphocyte responses during Plasmodium berghei ANKA infection.

The contribution of T cells in severe malaria pathogenesis has been described. Here, we provide evidence for the potential role of angiotensin II (Ang II) in modulating splenic T cell responses in a rodent model of cerebral malaria. T cell activation induced by infection, determined by 3 to 4-fold enhancement in CD69 expression, was reduced to control levels when mice were treated with 20 mg/kg losartan (IC50 = 0.966 mg/kg/d), an AT1 receptor antagonist, or captopril (IC50 = 1.940 mg/kg/d), an inhibitor of angiotensin-converting enzyme (ACE). Moreover, the production of interferon-γ and interleukin-17 by CD4+ T cells diminished 67% and 70%, respectively, by both treatments. Losartan reduced perforin expression in CD8+ T cells by 33% while captopril completely blocked it. The upregulation in chemokine receptor expression (CCR2 and CCR5) observed during infection was abolished and CD11a expression was partially reduced when mice were treated with drugs. T cells activated by Plasmodium berghei ANKA antigens showed 6-fold enhance in AT1 levels in comparison with naive cells. The upregulation of AT1 expression was reduced by losartan (80%) but not by captopril. Our results suggest that the AT1/Ang II axis has a role in the establishment of an efficient T cell response in the spleen and therefore could participate in a misbalanced parasite-induced T cell immune response during P. berghei ANKA infection.

Synthesis and trypanocidal activity of novel 2,4,5-triaryl-N-hydroxylimidazole derivatives.

Herein, we report the design, synthesis and trypanocidal activity of some novel trisubstituted imidazole derivatives. These heterocyclic derivatives were structurally planned by exploring the concept of molecular hybridisation between two arylhydrazones derived from megazol, which has potent trypanocidal activity. The trypanocidal activity of these triarylimidazole derivatives was evaluated against infective trypomastigote forms of T. cruzi and the derivative 2'-(4-bromophenyl)-1-methyl-5'-phenyl-1H,3'H-2,4'-biimidazol-3'-ol showed moderate biological activity (IC50 = 23.9 µM) when compared to benznidazole, a standard trypanocidal drug. These compounds did not present cytotoxic effects at concentrations near the trypanocidal IC50, being considered a good starting point for the development of new anti-Chagas drug candidates.

Early and late acute lung injury and their association with distal organ damage in murine malaria.

Severe malaria is characterised by cerebral oedema, acute lung injury (ALI) and multiple organ dysfunctions, however, the mechanisms of lung and distal organ damage need to be better clarified. Ninety-six C57BL/6 mice were injected intraperitoneally with 5×10(6)Plasmodium berghei ANKA-infected erythrocytes or saline. At day 1, Plasmodium berghei infected mice presented greater number of areas with alveolar collapse, neutrophil infiltration and interstitial oedema associated with lung mechanics impairment, which was more severe at day 1 than day 5. Lung tumour necrosis factor-α and chemokine (C-X-C motif) ligand 1 levels were higher at day 5 compared to day 1. Lung damage occurred in parallel with distal organ injury at day 1; nevertheless, lung inflammation and the presence of malarial pigment in distal organs were more evident at day 5. In conclusion, ALI develops prior to the onset of cerebral malaria symptoms. Later during the course of infection, the established systemic inflammatory response increases distal organ damage.

Artesunate Exerts a Direct Effect on Endothelial Cell Activation and NF-κB Translocation in a Mechanism Independent of Plasmodium Killing.

Artemisinin and its derivates are an important class of antimalarial drug and are described to possess immunomodulatory activities. Few studies have addressed the effect of artesunate in the murine malaria model or its effect on host immune response during malaria infection. Herein, we study the effect of artesunate treatment and describe an auxiliary mechanism of artesunate in modulating the inflammatory response during experimental malaria infection in mice. Treatment with artesunate did not reduce significantly the parasitemia within 12 h, however, reduced BBB breakdown and TNF-α mRNA expression in the brain tissue of artesunate-treated mice. Conversely, mefloquine treatment was not able to alter clinical features. Notably, artesunate pretreatment failed to modulate the expression of LFA-1 in splenocytes stimulated with parasitized red blood cells (pRBCs) in vitro; however, it abrogated the expression of ICAM-1 in pRBC-stimulated endothelial cells. Accordingly, a cytoadherence in vitro assay demonstrated that pRBCs did not adhere to artesunate-treated vascular endothelial cells. In addition, NF-κB nuclear translocation in endothelial cells stimulated with pRBCs was impaired by artesunate treatment. Our results suggest that artesunate is able to exert a protective effect against the P. berghei-induced inflammatory response by inhibiting NF-κB nuclear translocation and the subsequent expression of ICAM-1.