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Chagas disease is an infection caused by the protozoan Trypanosoma cruzi, affecting 6-8 million people worldwide. Only two drugs are available for its treatment, having a limited efficacy and adverse side-effects. Estafietin is a sesquiterpene lactone isolated from Stevia alpina with in vitro activity against T. cruzi and low cytotoxicity against mammalian cells. The aim of this work was to predict the toxicologic profile of estafietin by in silico methods and assess its in vivo activity on a murine model of Chagas disease. Estafietin showed low toxicity according to pkCSM web tool and passed the PAINS filter from PAINS-remover web server. The treatment of infected mice with 1 mg/Kg/day of estafietin for five consecutive days administrated by intraperitoneal route significatively decreased parasitemia levels and reduced inflammatory infiltrates and myocyte damage on muscle tissue. These results suggest that estafietin had effect both on acute and chronic stages of the infection. [ABSTRACT FROM AUTHOR] more...

Toxic shock syndrome toxin-1 (TSST-1), produced by Staphylococcus aureus, is one of the most potent superantigens involved in causing life-threatening TSS and contributes to the onset of some autoimmune diseases. To this end, we have previously identified a fully human single-chain variable fragment antibody (scFv), MS473, exhibiting high binding affinity and specificity for TSST-1 and demonstrating in vitro neutralization activity. In the present study, the therapeutic activity of MS473 was assessed in a D-galactosamine-sensitized mouse model of lethal shock. D-galactosamine-sensitized mice were injected with TSST-1 and then received a single dose of MS473 intraperitoneally (15 mg per kg of mouse body weight) after five minutes or intravenously (3 mg per kg of mouse body weight) after 10 min. The survival rate was examined for seven days. Furthermore, blood samples from different groups of mice were subjected to biochemical assessment, and their kidneys and livers were analyzed histopathologically 24 h after the toxin injection. The findings demonstrated a 100% survival rate with no significant damage to kidney and liver function in the treated groups, receiving MS473 through two different administration routes compared to the control groups, including the toxin-injected mice receiving normal saline or an unrelated scFv. Targeting disseminated TSST-1 with the scFv, which has appropriate permeability and distribution throughout the body, may be an effective way to alleviate the malfunctioning of the immune system caused by TSST-1. [ABSTRACT FROM AUTHOR] more...

Trichinella spiralis (T. spiralis) has been reported to induce inflammation, which can cause immune system dysregulation. Myeloid differentiation primary response gene 88 (MyD88) is implicated in inflammation signalling pathways. TJ-M2010-5 is a novel MyD88 inhibitor with remarkable protective effects against several diseases. However, the precise mechanism of TJ-M2010-5's involvement in spleen impairment and inflammation in the early infection of T. spiralis has yet to be fully elucidated. This study analysed histological, inflammation, and macrophage polarisation of the early T. spiralis-infected mice treated with TJ-M2010-5. MyD88 promoter methylation results showed that the methylation levels in the 5 d group were lower compared to the control group (P < 0.05). Furthermore, the methylation led to an imbalance in anti-inflammatory regulation in the infected mice. After TJ-M2010-5 treatment, spleen impairment was reduced. Sequencing analysis showed that TJ-M2010-5 significantly up-regulated 9 and down-regulated 10 miRNAs compared with the 5 d group. A dual-luciferase reporter assay further revealed that miR-136-5p is involved in the TJ-M2010-5 treatment by targeting AKT3. In RAW264.7 cells, TJ-M2010-5 pre-treatment significantly reversed the M1 polarisation and inhibited nitric oxide (NO) production. LC–MS/MS results showed TJ-M2010-5 was hepatosplenic-targeted. In conclusion, the study demonstrates that TJ-M2010-5 could effectively alleviate spleen impairment and reduce inflammation in mice infected with T. spiralis in its early stages by blocking the activation of PI3K/miR-136-5p/AKT3. [ABSTRACT FROM AUTHOR] more...

Leishmaniasis, a neglected tropical disease caused by Leishmania parasites, continues to pose global health challenges. Current treatments face issues like resistance, safety, efficacy, and cost. This review covers the discovery, mechanisms of action, clinical applications, and limitations of key antileishmanial agents: pentavalent antimonials, amphotericin B, miltefosine, paromomycin, and pentamidine. Despite toxicity and resistance (antimonials), hospitalization needs and side effects (amphotericin B), regional efficacy variability (miltefosine), inconsistent outcomes (paromomycin), and severe side effects (pentamidine), these drugs are vital. Novel strategies to overcome the deficiencies of current therapies are highlighted, including combination regimens, advanced drug delivery systems, and immunomodulatory approaches. Comprehensive and cooperative efforts are crucial to fully realize the potential of advancements in antileishmanial pharmacotherapy and to reduce the unacceptable worldwide burden imposed by this neglected disease. [ABSTRACT FROM AUTHOR] more...

Gold miners working illegally in mines live in poor health conditions related to their strenuous work and precarious housing. Therefore, they are at higher risk for infectious diseases. American tegumentary leishmaniasis (ATL) appears to be of great concern to the population living in the Guiana Shield region. Our aim was to describe their demographic characteristics, the clinical features of cutaneous leishmaniasis (CL), and the frequency of Leishmania infection in people working in illegal gold mines in French Guiana. A cross-sectional study was carried out from October to December 2019 in Oiapoque city, Amapá, Brazil. Indeed, many gold miners working in French Guiana are originally from Brazil, and from Oiapoque in particular. A total of 105 participants from 31 different mining sites in French Guiana were recruited. Suspected Leishmania infection was confirmed by the following: detection of kDNA in blood or the lesion site; detection of specific antibodies; or detection of IFN-γ release after blood incubation with leishmanial antigens (IGRA-Leish). Nine active CL cases, 38 healed ATL (hATL) and 58 cases with no history of ATL (noATL), were identified. Only half of the treated hATL (50.0%; n = 14) reported having been assisted by a health care unit and the others treated themselves. PCR-kDNA for Leishmania was positive in the blood of 100% of CL cases. Curiously, blood PCR-kDNA was positive in 13% of hATL patients and in 15.5% of noATL patients. The IGRA-Leish was positive in 60.5% of hATL and in 37.9% of noATL. In addition to scars suggestive of CL, 71% of hATL had laboratory evidence of Leishmania infection. Restriction fragment polymorphism (RFLP) of the hsp70 gene identified a sympatric circulation of L. (V.) guyanensis (n = 4), L. (V.) braziliensis (n = 1), L. (L.) amazonensis (n = 2), L. (V.) shawi (n = 1) and L. (V.) naiffi/shawi (n = 1). Taking the laboratory techniques and the clinical evaluations together, 76% (n = 80) of the 105 participants had evidence of Leishmania infection. These results suggests that illegal gold miners working in French Guiana are at high risk for infection with different species of Leishmania, but their illegal condition and remoteness make it difficult for them to access health services. Author summary: American tegumentary leishmaniasis (ATL), a tropical disease, appears to be of great concern to the gold miners working in the Guiana Shield region. Indeed, many gold miners working in French Guiana are originally from Brazil. The frequency of Leishmania infection, the clinical features of lesions and scars of ATL, and the demographic characteristics were described among this population. A cross-sectional study was carried out from October to December 2019 in Oiapoque city, Amapá, Brazil. A total of 105 participants were recruited. Suspected Leishmania infection was confirmed by the detection of Leishmania kDNA or detection of specific immune response to leishmanial antigens. Nine active ATL, 38 healed ATL (hATL) and 58 cases with no history of ATL (noATL), were identified. Only half of the treated hATL (50.0%; n = 14) reported having been assisted by a health care unit and the others treated themselves. Taking the laboratory techniques and the clinical evaluations together, 76% (n = 80) of participants had evidence of Leishmania infection. These results suggests that illegal gold miners working in French Guiana are at high risk for infection with different species of Leishmania, but their illegal condition and remoteness make it difficult for them to access health services. [ABSTRACT FROM AUTHOR] more...

Chagas disease—caused by the parasite Trypanosoma cruzi—is a neglected tropical disease for which available drugs are not fully effective in the chronic stage and a vaccine is not available yet. Microalgae represent a promising platform for the production and oral delivery of low-cost vaccines. Herein, we report a vaccine prototype against T. cruzi produced in a microalgae platform, based on the candidate antigen Tc24 with a C terminus fusion with the Co1 peptide (Tc24:Co1 vaccine prototype). After modeling the tertiary structure, in silico studies suggested that the chimeric protein is antigenic, not allergenic, and molecular docking indicated binding with Toll-like receptors 2 and 4. Thus, Tc24:Co1 was expressed in the marine microalga Schizochytrium sp., and Western blot confirmed the expression at 48 h after induction, with a yield of 632 µg/L of algal culture (300 μg/g of lyophilized algal cells) as measured by the enzyme-linked immunosorbent assay (ELISA). Upon oral administration of whole-cell Schizochytrium sp. expressing Tc24:Co1 (7.5 µg or 15 µg of Tc24:Co1 doses) in mice, specific serum IgG and intestinal mucosa IgA responses were detected in addition to an increase in serum Th1/Th2 cytokines. In conclusion, Schizochytrium sp.-expressing Tc24:Co1 is a promising oral vaccine prototype to be evaluated in an animal model of Trypanosoma cruzi infection. [ABSTRACT FROM AUTHOR] more...

Introduction: There is currently no vaccine against Chagas disease (ChD), and the medications available confer multiple side effects. Mycobacterium bovis Bacillus Calmette-Guerin (BCG) produces balanced Th1, Th2, and Th17 modulatory immune responses and has improved efficacy in controlling chronic infections through nonspecific immunity. We aimed to improve the response to infection by inducing a stronger immune response and greater protection against the parasite by trained immunity. Methods: BALB/c mice were immunized with BCG subcutaneously, and 60 days later, they were infected with Trypanosoma cruzi intraperitoneally. An evaluation of the progression of the disease from the acute to the chronic stage, analyzing various aspects such as parasitemia, survival, clinical status, and humoral and cellular immune response, as well as the appearance of visceral megas and the histopathological description of target organs, was performed. Results: Vaccination reduced parasitemia by 70%, and 100% survival was achieved in the acute stage; although the presentation of clinical signs was reduced, there was no increase in the antibody titer or in the differential production of the isotypes. Conclusion: Serum cytokine production indicated a proinflammatory response in infected animals, while in those who received BCG, the response was balanced by inducing Th1/Th2-type cytokines, with a better prognosis of the disease in the chronic stage. [ABSTRACT FROM AUTHOR] more...

Aplastic anemia (AA) and hypoplastic myelodysplastic syndrome are paradigms of autoimmune hematopoietic failure (AHF). Myelodysplastic syndrome and acute myeloid leukemia are unequivocal myeloid neoplasms (MNs). Currently, AA is also known to be a clonal hematological disease. Genetic aberrations typically observed in MNs are detected in approximately one-third of AA patients. In AA patients harboring MN-related genetic aberrations, a poor response to immunosuppressive therapy (IST) and an increased risk of transformation to MNs occurring either naturally or after IST are predicted. Approximately 10%-15% of patients with severe AA transform the disease phenotype to MNs following IST, and in some patients, leukemic transformation emerges during or shortly after IST. Phenotypic transformations between AHF and MNs can occur reciprocally. A fraction of advanced MN patients experience an aplastic crisis during which leukemic blasts are repressed. The switch that shapes the disease phenotype is a change in the strength of extramedullary inflammation. Both AHF andMNs have an immune-active bone marrow (BM) environment (BME). In AHF patients, an inflamed BME can be evoked by infiltrated immune cells targeting neoplastic molecules, which contributes to the BM-specific autoimmune impairment. Autoimmune responses in AHF may represent an antileukemic mechanism, and inflammatory stressors strengthen antileukemic immunity, at least in a significant proportion of patients who have MN-related genetic aberrations. During active inflammatory episodes, normal and leukemic hematopoieses are suppressed, which leads to the occurrence of aplastic cytopenia and leukemic cell regression. The successful treatment of underlying infections mitigates inflammatory stress-related antileukemic activities and promotes the penetration of leukemic hematopoiesis. The effect of IST is similar to that of treating underlying infections. Investigating inflammatory stress-powered antileukemic immunity is highly important in theoretical studies and clinical practice, especially given the wide application of immune-activating agents and immune checkpoint inhibitors in the treatment of hematological neoplasms. [ABSTRACT FROM AUTHOR] more...

The tumor microenvironment is a highly complex and dynamic mixture of cell types, including tumor, immune and endothelial cells (ECs), soluble factors (cytokines, chemokines, and growth factors), blood vessels and extracellular matrix. Within this complex network, ECs are not only relevant for controlling blood fluidity and permeability, and orchestrating tumor angiogenesis but also for regulating the antitumor immune response. Lining the luminal side of vessels, ECs check the passage of molecules into the tumor compartment, regulate cellular transmigration, and interact with both circulating pathogens and innate and adaptive immune cells. Thus, they represent a first-line defense system that participates in immune responses. Tumor-associated ECs are involved in T cell priming, activation, and proliferation by acting as semi-professional antigen presenting cells. Thus, targeting ECs may assist in improving antitumor immune cell functions. Moreover, tumor-associated ECs contribute to the development at the tumor site of tertiary lymphoid structures, which have recently been associated with enhanced response to immune checkpoint inhibitors (ICI). When compared to normal ECs, tumor-associated ECs are abnormal in terms of phenotype, genetic expression profile, and functions. They are characterized by high proliferative potential and the ability to activate immunosuppressive mechanisms that support tumor progression and metastatic dissemination. A complete phenotypic and functional characterization of tumor-associated ECs could be helpful to clarify their complex role within the tumor microenvironment and to identify EC specific drug targets to improve cancer therapy. The emerging therapeutic strategies based on the combination of anti-angiogenic treatments with immunotherapy strategies, including ICI, CAR T cells and bispecific antibodies aim to impact both ECs and immune cells to block angiogenesis and at the same time to increase recruitment and activation of effector cells within the tumor. [ABSTRACT FROM AUTHOR] more...

Rhinosinusitis (RS) is an acute (ARS) or chronic (CRS) inflammatory disease of the nasal and paranasal sinus mucosa. CRS is a heterogeneous condition characterized by distinct inflammatory patterns (endotypes) and phenotypes associated with the presence (CRSwNP) or absence (CRSsNP) of nasal polyps. Mucosal barrier and mucociliary clearance dysfunction, inflammatory cell infiltration, mucus hypersecretion, and tissue remodeling are the hallmarks of CRS. However, the underlying factors, their priority, and the mechanisms of inflammatory responses remain unclear. Several hypotheses have been proposed that link CRS etiology and pathogenesis with host (eg, "immune barrier") and exogenous factors (eg, bacterial/fungal pathogens, dysbiotic microbiota/biofilms, or staphylococcal superantigens). The abnormal interplay between these factors is likely central to the pathophysiology of CRS by triggering compensatory immune responses. Here, we discuss the role of the sinonasal microbiota in CRS and its biofilms in the context of mucosal zinc (Zn) deficiency, serving as a possible unifying link between five host and "bacterial" hypotheses of CRS that lead to sinus mucosa remodeling. To date, no clear correlation between sinonasal microbiota and CRS has been established. However, the predominance of Corynebacteria and Staphylococci and their interspecies relationships likely play a vital role in the formation of the CRS-associated microbiota. Zn-mediated "nutritional immunity", exerted via calprotectin, alongside the dysregulation of Zn-dependent cellular processes, could be a crucial microbiota-shaping factor in CRS. Similar to cystic fibrosis (CF), the role of SPLUNC1-mediated regulation of mucus volume and pH in CRS has been considered. We complement the biofilms' "mechanistic" and "mucin" hypotheses behind CRS pathogenesis with the "structural" one – associated with bacterial "corncob" structures. Finally, microbiota restoration approaches for CRS prevention and treatment are reviewed, including pre- and probiotics, as well as Nasal Microbiota Transplantation (NMT). [ABSTRACT FROM AUTHOR] more...

The impact of dopamine on synaptic plasticity and cognitive function following seizure is not well understood. Here, using optogenetics in the freely behaving animal, we examined exploratory behavior and short-term memory in control and kindled male mice during tonic stimulation of dopaminergic neurons within the ventral tegmental area (VTA). Furthermore, using field potential recording, we compared the effect of dopamine on synaptic plasticity in stratum radiatum and stratum oriens layers of both ventral and dorsal hippocampal CA1 regions, and again in both control and kindled male mice. Our results demonstrate that tonic stimulation of VTA dopaminergic neurons enhances novelty-driven exploration and short-term spatial memory in kindled mice, essentially rescuing the seizure-induced cognitive impairment. In addition, we found that dopamine has a dual effect on LTP in control versus kindled mice, such that application of dopamine prevented LTP induction in slices from control mice, but rescued LTP in slices taken from the kindled animal. Taken together, our results highlight the potential for dopaminergic modulation in improving synaptic plasticity and cognitive function following seizure. [ABSTRACT FROM AUTHOR] more...

The misuse and overuse of antibiotics have contributed to a rapid emergence of antibiotic-resistant bacterial pathogens. This global health threat underlines the urgent need for innovative and novel antimicrobials. Endolysins derived from bacteriophages or prophages constitute promising new antimicrobials (so-called enzybiotics), exhibiting the ability to break down bacterial peptidoglycan (PG). In the present work, metagenomic analysis of soil samples, collected from thermal springs, allowed the identification of a prophage-derived endolysin that belongs to the N-acetylmuramoyl-L-alanine amidase type 2 (NALAA-2) family and possesses a LysM (lysin motif) region as a cell wall binding domain (CWBD). The enzyme (Ami1) was cloned and expressed in Escherichia coli, and its bactericidal and lytic activity was characterized. The results indicate that Ami1 exhibits strong bactericidal and antimicrobial activity against a broad range of bacterial pathogens, as well as against isolated peptidoglycan (PG). Among the examined bacterial pathogens, Ami1 showed highest bactericidal activity against Staphylococcus aureus sand Staphylococcus epidermidis cells. Thermostability analysis revealed a melting temperature of 64.2 ± 0.6 °C. Overall, these findings support the potential that Ami1, as a broad spectrum antimicrobial agent, could be further assessed as enzybiotic for the effective treatment of bacterial infections. Key points: • Metagenomic analysis allowed the identification of a novel prophage endolysin • The endolysin belongs to type 2 amidase family with lysin motif region • The endolysin displays high thermostability and broad bactericidal spectrum [ABSTRACT FROM AUTHOR] more...

Staphylococcus aureus is a major human pathogen associated with high mortality rates. The extensive use of antibiotics is associated with the rise of drug resistance, and exotoxins are not targeted by antibiotics. Therefore, monoclonal antibody (mAb) therapy has emerged as a promising solution to solve the clinical problems caused by refractory S aureus. Recent research suggests that the synergistic effects of several cytotoxins, including bicomponent toxins, are critical to the pathogenesis of S aureus. By comparing the amino acid sequences, researchers found that α-toxin and bicomponent toxins have high homology. Therefore, we aimed to screen an antibody, designated an all-in-one mAb, that could neutralize α-toxin and bicomponent toxins through hybridoma fusion. We found that this mAb has a significant pharmacodynamic effect within in vivo mouse models and in vitro experiments. [ABSTRACT FROM AUTHOR] more...

Trypanosoma cruzi is the causative agent of American trypanosomiasis, which mainly affects populations in Latin America. Benznidazole is used to control the disease, with severe effects in patients receiving this chemotherapy. Previous studies have demonstrated the inhibition of triosephosphate isomerase from T. cruzi, but cellular enzyme inhibition has yet to be established. This study demonstrates that rabeprazole inhibits both cell viability and triosephosphate isomerase activity in T. cruzi epimastigotes. Our results show that rabeprazole has an IC50 of 0.4 µM, which is 14.5 times more effective than benznidazole. Additionally, we observed increased levels of methyl-glyoxal and advanced glycation end products after the inhibition of cellular triosephosphate isomerase by rabeprazole. Finally, we demonstrate that the inactivation mechanisms of rabeprazole on triosephosphate isomerase of T. cruzi can be achieved through the derivatization of three of its four cysteine residues. These results indicate that rabeprazole is a promising candidate against American trypanosomiasis. [ABSTRACT FROM AUTHOR] more...

Previous studies showed that Trichinella spiralis galectin (Tsgal) facilitates larval invasion of intestinal epithelium cells (IECs). However, IEC proteins binding with Tsgal were not identified, and the mechanism by which Tsgal promotes larval invasion is not clear. Toll-like receptors (TLRs) are protein receptors responsible for recognition of pathogens. The aim of this study was to investigate whether recombinant Tsgal (rTsgal) binds to TLR-4, activates inflammatory pathway in gut epithelium and mediates T. spiralis invasion. Indirect immunofluorescence (IIF), GST pull-down and co-immunoprecipitation (Co-IP) assays confirmed specific binding between rTsgal and TLR-4 in Caco-2 cells. qPCR and Western blotting showed that binding of rTsgal with TLR-4 up-regulated the TLR-4 transcription and expression in Caco-2 cells, and activated p-NF-κB p65 and p-ERK1/2. Activation of inflammatory pathway TLR-4/MAPK-NF-κB by rTsgal up-regulated pro-inflammatory cytokines (IL-1β and IL-6) and down-regulated anti-inflammatory cytokine TGF-β in Caco-2 cells, and induced intestinal inflammation. TAK-242 (TLR-4 inhibitor) and PDTC (NF-κB inhibitor) significantly inhibited the activation of TLR-4 and MAPK-NF-κB pathway. Moreover, the two inhibitors also inhibited IL-1β and IL-6 expression, and increased TGF-β expression in Caco-2 cells. In T. spiralis infected mice, the two inhibitors also inhibited the activation of TLR-4/MAPK-NF-κB pathway, ameliorated intestinal inflammation, impeded larval invasion of gut mucosa and reduced intestinal adult burdens. The results showed that rTsgal binding to TLR-4 in gut epithelium activated MAPK-NF-κB signaling pathway, induced the expression of TLR-4 and pro-inflammatory cytokines, and mediated larval invasion. Tsgal might be regarded as a candidate molecular target of vaccine against T. spiralis enteral invasive stage. [ABSTRACT FROM AUTHOR] more...

The interest in Smallanthus sonchifolius (yacon) has strongly resurfaced due to its multiple beneficial effects on human health. This study aimed at determining the toxicity and the chemical profile of an ethanol extract (EE) and a crude lactone mixture (CLM) of yacon leaves. Cytotoxicity and genotoxicity tests were performed by the MTT assay and the alkaline version of the comet assay respectively. The phytochemical analysis, performed by chromatographic and spectroscopy techniques, revealed the presence of nine sesquiterpene lactones (STLs) and two acyclic diterpene acids. In all cases, cell viability was inversely proportional to the extract concentration employed. The effects obtained with the highest dose of EE were significantly different from those obtained with the negative and solvent controls. Conversely, no significant differences were observed between the lowest doses of EE and controls. As for CLM, all tested doses showed statistically significant increases, as compared to negative and solvent controls. [ABSTRACT FROM AUTHOR] more...

Background: Coronavirus disease 2019 (COVID-19) is a serious pandemic infectious disease that spread all over the world with a wide variety of complications. The need for easily available markers that can assess the severity and prognosis of the disease nowadays is a great demand. Aim: Study the dynamic changes in NLR and PLR during treatment of confirmed COVID-19 patient in the ICU regarding prognosis and mortality. Method: A retrospective cross-sectional study included 67 patients, with a confirmed COVID-19 by Real time PCR and meet the criteria of hospitalization. Patients were followed up daily for denoting their outcome. NLR and PLR were calculated and compared with other proven biomarkers for COVID-19 to predict prognosis, mortality, and assess their sensitivity and specificity. Result: A total of 67 ICU patients with COVID-19 were enrolled in the current study, 40 were improved and 27 died. Died patients had older age compared with improved patients. Neutrophils were significantly higher among dead patients compared to improved ones (p-value= 0.035). It was found that the NLR & PLR were significantly higher in dead compared to improved patients as follow (p= 0.007) and (p= 0.041), that, may help in the early detection of Covid-19 patients who need more aggressive clinical management. The data showed that there was a high significance of NLR and PLR (p<0.001) in the mortality prediction state. Conclusion: Both NLR and PLR are good predictors biomarkers for severity and mortality in ICU COVID-19 patients. [ABSTRACT FROM AUTHOR] more...

Trans‐sialidase (TS) superfamily of proteins comprises eight subgroups, being the proteins of Group‐I (TS‐GI) promising immunogens in vaccine approaches against Trypanosoma cruzi. Strikingly, TS‐GI antigenic variability among parasite lineages and their influence on vaccine development has not been previously analyzed. Here, a search in GenBank detects 49 TS‐GI indexed sequences, whereas the main infecting human different parasite discrete typing units (DTU) are represented. In silico comparison among these sequences indicate that they share an identity above 92%. Moreover, the antigenic regions (T‐cell and B‐cell epitopes) are conserved in most sequences or present amino acid substitutions that scarcely may alter the antigenicity. Additionally, since the generic term TS is usually used to refer to different immunogens of this broad family, a further in silico analysis of the TS‐GI‐derived fragments tested in preclinical vaccines was done to determine the coverage and identity among them, showing that overall amino acid identity of vaccine immunogens is high, but the segment coverage varies widely. Accordingly, strong H‐2K, H‐2I, and B‐cell epitopes are dissimilarly represented among vaccine TS‐derived fragments depending on the extension of the TG‐GI sequence used. Moreover, bioinformatic analysis detected a set of 150 T‐cell strong epitopes among the DTU‐indexed sequences that strongly bind human HLA‐I supertypes. In all currently reported experimental vaccines based on TS‐GI fragments, mapping these 150 epitopes showed that they are moderately represented. However, despite vaccine epitopes do not present all the substitutions observed in the DTUs, these regions of the proteins are equally recognized by the same HLAs. Interestingly, the predictions regarding global and South American population coverage estimated in these 150 epitopes are similar to the estimations in experimental vaccines when the complete sequence of TS‐GI is used as an antigen. In silico prediction also shows that a number of these MHC‐I restricted T‐cell strong epitopes could be also cross‐recognized by HLA‐I supertypes and H‐2Kb or H‐2Kd backgrounds, indicating that these mice may be used to improve and facilitate the development of new TS‐based vaccines and suggesting an immunogenic and protective potential in humans. Further molecular docking analyses were performed to strengthen these results. Taken together, different strategies that would cover more or eventually fully of these T‐cell and also B‐cell epitopes to reach a high level of coverage are considered. [ABSTRACT FROM AUTHOR] more...

Chagas disease is the most important protozoan infection in the Americas, and constitutes a significant public health concern throughout the world. Development of new medications against its etiologic agent, Trypanosoma cruzi, has been traditionally slow and difficult, lagging in comparison with diseases caused by other kinetoplastid parasites. Among the factors that explain this are the incompletely understood mechanisms of pathogenesis of T. cruzi infection and its complex set of interactions with the host in the chronic stage of the disease. These demand the performance of a variety of in vitro and in vivo assays as part of any drug development effort. In this review, we discuss recent breakthroughs in the understanding of the parasite's life cycle and their implications in the search for new chemotherapeutics. For this, we present a framework to guide drug discovery efforts against Chagas disease, considering state-of-the-art preclinical models and recently developed tools for the identification and validation of molecular targets. [ABSTRACT FROM AUTHOR] more...

The aim of this work was to evaluate the antifungal and antiparasitic activity of roots of Wunderlichia azulensis (Asteraceae). A CH2Cl2 partition of W. azulensis was tested against Candida tropicalis, C. buinensis and Trypanosoma cruzi parasites. A chemical study of the CH2Cl2 partition resulted in the isolation and identification of dehydrobrachylaenolide (1), lasiodiplodin (2), a taraxerane-type triterpene (3) and a mixture of sitosterol and stigmasterol (4–5). Of the 13 fractions tested, fractions 5 and 7 were the most bioactive ones. No live epimastigotes were observed even after the shortest time of exposure to fraction 7 (25 μg.mL−1/24 h). Fractions 5 and 7 inhibited yeast growth in proportions between 63.9–80.7% at 50 μg.mL−1, and 70.3–96.7% at 100 μg.mL−1. Fractions 5 and 7 (100 μg.mL−1) induced loss of viability of C. buinensis by 97.61 and 92.63%, respectively, whereas C. tropicalis was less susceptible. The SYTOX Green marker used on Candida yeasts suggested membrane permeabilization and consequently plasma membrane damage. We concluded that W. azulensis offers new sources of biologically-active components. However, complementary studies on other variables, such as synergy, toxicology, and mechanism of action, must be carried out. [ABSTRACT FROM AUTHOR] more...

Immunization with the Amastigote Surface Protein-2 (ASP-2) and Trans-sialidase (TS) antigens either in the form of recombinant protein, encoded in plasmids or human adenovirus 5 (hAd5) confers robust protection against various lineages of Trypanosoma cruzi. Herein we generated a chimeric protein containing the most immunogenic regions for T and B cells from TS and ASP-2 (TRASP) and evaluated its immunogenicity in comparison with our standard protocol of heterologous prime-boost using plasmids and hAd5. Mice immunized with TRASP protein associated to Poly-ICLC (Hiltonol) were highly resistant to challenge with T. cruzi, showing a large decrease in tissue parasitism, parasitemia and no lethality. This protection lasted for at least 3 months after the last boost of immunization, being equivalent to the protection induced by DNA/hAd5 protocol. TRASP induced high levels of T. cruzi-specific antibodies and IFNγ-producing T cells and protection was primarily mediated by CD8+ T cells and IFN-γ. We also evaluated the toxicity, immunogenicity, and efficacy of TRASP and DNA/hAd5 formulations in dogs. Mild collateral effects were detected at the site of vaccine inoculation. While the chimeric protein associated with Poly-ICLC induced high levels of antibodies and CD4+ T cell responses, the DNA/hAd5 induced no antibodies, but a strong CD8+ T cell response. Immunization with either vaccine protected dogs against challenge with T. cruzi. Despite the similar efficacy, we conclude that moving ahead with TRASP together with Hiltonol is advantageous over the DNA/hAd5 vaccine due to pre-existing immunity to the adenovirus vector, as well as the cost-benefit for development and large-scale production. [ABSTRACT FROM AUTHOR] more...

ContextChagas’ disease and leishmaniasis produce significant disability and mortality with great social and economic impact. The genusStevia(Asteraceae) is a potential source of antiprotozoal compounds. ObjectiveAerial parts of fourSteviaspecies were screened onTrypanosoma cruzi.Stevia satureiifolia(Lam.) Sch. Bip. var.satureiifolia(Asteraceae) dichloromethane extract was selected for a bioassay-guided fractionation in order to isolate its active compounds. Additionally, the antileishmanial activity and the cytotoxicity of these compounds on mammalian cells were assessed. Materials and methodsThe dichloromethane extract was fractionated by column chromatography. The isolated compounds were evaluated using concentrations of 0–100 μg/mL onT. cruziepimastigotes and onLeishmania braziliensispromastigotes for 72 h, on trypomastigotes and amastigotes ofT. cruzifor 24 h and 120 h, respectively. The compounds’ cytotoxicity (12.5–500 μg/mL) was assessed on Vero cells by the MTT assay. The structure elucidation of each compound was performed by spectroscopic methods and HPLC analysis. ResultsThe dichloromethane extracts ofSteviaspecies showed significant activity onT. cruziepimastigotes. The flavonoids eupatorin (1.3%), cirsimaritin (1.9%) and 5-desmethylsinensetin (1.5%) were isolated fromS. satureiifoliavar.satureiifoliaextract. Eupatorin and 5-desmethylsinensetin showed IC50values of 0.2 and 0.4 μg/mL onT. cruziepimastigotes and 61.8 and 75.1 μg/mL on trypomastigotes, respectively. The flavonoid 5-desmethylsinensetin showed moderate activity againstT. cruziamastigotes (IC50 value = 78.7 μg/mL) and was the most active compound onL. braziliensispromastigotes (IC50 value = 37.0 μg/mL). Neither of the flavonoids showed cytotoxicity on Vero cells, up to a concentration of 500 μg/mL. [ABSTRACT FROM PUBLISHER] more...

Major Histocompatibility Complex class I (MHC-I) molecules display self, viral or aberrant epitopic peptides to T cell receptors (TCRs), which employ interactions between complementarity-determining regions with both peptide and MHC-I heavy chain ‘framework’ residues to recognize specific Human Leucocyte Antigens (HLAs). The highly polymorphic nature of the HLA peptide-binding groove suggests a malleability of interactions within a common structural scaffold. Here, using structural data from peptide:MHC-I and pMHC:TCR structures, we first identify residues important for peptide and/or TCR binding. We then outline a fixed-backbone computational design approach for engineering synthetic molecules that combine peptide binding and TCR recognition surfaces from existing HLA allotypes. X-ray crystallography demonstrates that chimeric molecules bridging divergent HLA alleles can bind selected peptide antigens in a specified backbone conformation. Finally, in vitro tetramer staining and biophysical binding experiments using chimeric pMHC-I molecules presenting established antigens further demonstrate the requirement of TCR recognition on interactions with HLA framework residues, as opposed to interactions with peptide-centric Chimeric Antigen Receptors (CARs). Our results underscore a novel, structureguided platform for developing synthetic HLA molecules with desired properties as screening probes for peptide-centric interactions with TCRs and other therapeutic modalities. [ABSTRACT FROM AUTHOR] more...

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Background: Chagas disease (CD) is caused by Trypanosoma cruzi. The chronic phase of CD is characterized by the presence of IgG anti-T. cruzi antibodies; and diagnosis is performed by serological methods. Because there is no realible test that can be used as a reference test, WHO recommends the parallel use of two different tests for CD serodiagnosis. If results are inconclusive, samples should be subjected to a confirmatory test, e.g., Western blot (WB) or PCR. PCR offers low sensitivity in the chronic phase, whereas few confirmatory tests based on the WB method are commercially available worldwide. Therefore, new diagnostic tools should be evaluated to fill the gap in confirmatory tests CD. In recent years, four chimeric recombinant antigens (IBMP-8.1, IBMP-8.2, IBMP-8.3 and IBMP-8.4) have been evaluated in phase I, II and III studies using ELISA, liquid microarray and immunochromatography with 95–100% accuracy. Given the high diagnostic performance of these antigens, the present study investigated the ability of these molecules to diagnose chronic CD using a WB testing platform. Methodology/Principal findings: In this study, we analyzed the diagnostic potential of four chimeric antigens using 40 T. cruzi-positive, 24-negative, and three additional samples positive for visceral leishmaniasis (i.e., potentially cross-reactive) using WB as the diagnostic platform. Checkerboard titration with different dilutions of antigens, conjugated antigens, and serum samples was performed to standardize all assays. All IBMP antigens achieved 100% sensitivity, specificity, and accuracy, with the exception of IBMP-8.3, which had 100% specificity despite lack of significance, but lower sensitivity (95%) and accuracy (96.9%). No cross-reactivity was observed in samples positive for leishmaniasis. Conclusions/Significance: The present phase I (proof-of-concept) study demonstrated the high diagnostic potential of these four IBMP antigens to discriminate between T. cruzi-positive and -negative samples, making them candidates for phase II and confirmatory testing with WB. Author summary: Chagas disease is a neglected infection that occurs mainly in Latin American countries. Infection occurs in several ways, the most common being vector infection by kissing bugs (family Triatominae). The disease progresses in two phases: acute and chronic. Since there is no reliable test that could serve as a gold standard, WHO recommends the parallel use of two tests. Conflicting results lead to an inconclusive diagnosis. In these cases, a confirmatory test is required, such as a Western blot (WB). However, few confirmatory tests based on the WB method are commercially available worldwide. Therefore, the aim of this study was to evaluate the use of four chimeric T. cruzi proteins developed by our group (IBMP-8.1, IBMP-8.2, IBMP-8.3, and IBMP-8.4) to distinguish T. cruzi positive and negative samples. Forty T. cruzi-positive samples, 24-negative, and three additional positive samples for visceral leishmaniasis were evaluated. All IBMP antigens achieved 100% sensitivity, specificity, and accuracy, with the exception of IBMP-8.3, which had 100% specificity despite lack of significance, but lower sensitivity (95%) and accuracy (96.9%). No cross-reactivity was observed in samples positive for leishmaniasis. The present phase I (proof-of-concept) study demonstrated the high diagnostic potential of these four IBMP antigens to discriminate between T. cruzi-positive and -negative samples, making them candidates for phase II and confirmatory testing with WB. [ABSTRACT FROM AUTHOR] more...

While the majority of children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) display mild or no symptoms, rare individuals develop severe disease presenting with multisystem inflammatory syndrome (MIS-C). The reason for variable clinical manifestations is not understood. Here, we carried out TCR sequencing and conducted comparative analyses of TCR repertoires between children with MIS-C (n = 12) and mild (n = 8) COVID-19. We compared these repertoires with unexposed individuals (samples collected pre-COVID-19 pandemic: n = 8) and with the Adaptive Biotechnologies MIRA dataset, which includes over 135,000 high-confidence SARS-CoV-2-specific TCRs. We show that the repertoires of children with MIS-C are characterised by the expansion of TRBV11-2 chains with high junctional and CDR3 diversity. Moreover, the CDR3 sequences of TRBV11-2 clones shift away from SARS-CoV-2 specific T cell clones, resulting in distorted TCR repertoires. In conclusion, our study reports that CDR3-independent expansion of TRBV11-2+ cells, lacking SARS-CoV-2 specificity, defines MIS-C in children. [ABSTRACT FROM AUTHOR] more...

Trypanosoma cruzi is the causative protozoan of Chagas' Disease, a neglected tropical disease that affects 6-7 million people worldwide. Interaction of the parasite with the host immune system is a key factor in disease progression and chronic symptoms. Although the human immune system is capable of controlling the disease, the parasite has numerous evasion mechanisms that aim to maintain intracellular persistence and survival. Due to the pronounced genetic variability of T. cruzi, co-infections or mixed infections with more than one parasite strain have been reported in the literature. The intermodulation in such cases is unclear. This study aimed to evaluate the co-infection of T. cruzi strains G and CL compared to their individual infections in human macrophages derived from THP-1 cells activated by classical or alternative pathways. Flow cytometry analysis demonstrated that trypomastigotes were more infective than extracellular amastigotes (EAs) and that strain G could infect more macrophages than strain CL. Classically activated macrophages showed lower number of infected cells and IL-4-stimulated cells displayed increased CL-infected macrophages. However, co-infection was a rare event. CL EAs decreased the production of reactive oxygen species (ROS), whereas G trypomastigotes displayed increased ROS detection in classically activated cells. Co-infection did not affect ROS production. Monoinfection by strain G or CL mainly induced an anti-inflammatory cytokine profile by decreasing inflammatory cytokines (IFN-g, TNF-a, IL-1b) and/or increasing IL-4, IL-10, and TGF-b. Co-infection led to a predominant inflammatory milieu, with reduced IL-10 and TGF-b, and/or promotion of IFN-g and IL-1b release. Infection by strain G reduced activation of intracellular signal transducer and activator of transcription (STAT) factors. In EAs, monoinfections impaired STAT-1 activity and promoted phosphorylation of STAT-3, both changes may prolong cell survival. Coinfected macrophages displayed pronounced activation of all STATs examined. These activations likely promoted parasite persistence and survival of infected cells. The collective results demonstrate that although macrophages respond to both strains, T. cruzi can modulate the intracellular environment, inducing different responses depending on the strain, parasite infective form, and co-infection or monoinfection. The modulation influences parasite persistence and survival of infected cells. [ABSTRACT FROM AUTHOR] more...

Background: Forest musk deer is an endangered species globally. The death of captive forest musk deer can be caused by certain respiratory system diseases. Acute respiratory distress syndrome (ARDS) is a huge threat to the life of forest muck deer that breed in our department. Methods: Lung histopathologic analysis was conducted by hematoxylin and eosin (HE) staining. The lung gene changes triggered by ARDS were examined by RNA sequencing and related bioinformatics analysis in forest musk deer. The potential functions of unigenes were investigated by NR, SwissProt KOG, GO, and KEGG annotation analyses. Vital biological processes or pathways in ARDS were examined by GO and KEGG enrichment analyses. Results: A total of 3265 unigenes were differentially expressed (|log2fold-change|> 2 and adjusted P value < 0.01) in lung tissues of 3 forest musk deer with ARDS compared with normal lung tissues of the non-ARDS group. These differentially expressed unigenes (DEGs) played crucial roles in immunity and defense responses to pathogens. Moreover, we identified the DEGs related to one or more of the following biological processes: lung development, immunity, and bacterial/viral/fungal infection. And six DEGs that might be involved in lung injury caused by immune dysregulation or viral/fungal infection were identified. Conclusion: ARDS-mediated lung gene alterations were identified in forest musk deer. Moreover, multiple genes involved in lung development and lung defense responses to bacteria/viruses/fungi in ARDS were filtered out in forest musk deer. [ABSTRACT FROM AUTHOR] more...

Purpose: To determine whether mitochondrial DNA copy number (mtDNA-CN) is associated with allergic rhinitis (AR), and further establish a nomogram model for the early diagnosis of AR. Methods: We carried out a case-control study involving a total of 134 subjects, including 66 healthy controls and 68 AR patients. The mtDNA-CN in peripheral blood of all subjects was detected by real-time fluorescence quantitative polymerase chain reaction, and general information of patients was recorded. And, least absolute shrinkage selection operator (LASSO) regression was used to screen clinically significant variables, which were substituted into a logistic regression analysis to determine independent risk factors. Next, a nomogram model was developed for the risk prediction of AR. Then, internal validation was performed with the bootstrap resampling. Ultimately, the clinical benefit and validity of the nomogram were assessed by receiver operating characteristic (ROC) curve, bias-corrected curve, and decision curve analysis (DCA). Results: MtDNA-CN and total IgE were determined as independent risk factors of AR. The final model achieved an area under the ROC curve (AUC) of 0.869, and the DCA curve demonstrated that the nomogram was clinically beneficial for practical application. Conclusion: An increase of the mtDNA-CN was linked to the occurrence risk of AR. The nomogram prediction model based on mtDNA-CN showed the potential clinical utility in improving risk prediction and providing new insights for exploring the pathogenesis of AR. [ABSTRACT FROM AUTHOR] more...

Loading of MHC-I molecules with peptide by the catalytic chaperone tapasin in the peptide loading complex plays a critical role in antigen presentation and immune recognition. Mechanistic insight has been hampered by the lack of detailed structural information concerning tapasin–MHC-I. We present here crystal structures of human tapasin complexed with the MHC-I molecule HLA-B*44:05, and with each of two anti-tapasin antibodies. The tapasin-stabilized peptide-receptive state of HLA-B*44:05 is characterized by distortion of the peptide binding groove and destabilization of the β2-microglobulin interaction, leading to release of peptide. Movements of the membrane proximal Ig-like domains of tapasin, HLA-B*44:05, and β2-microglobulin accompany the transition to a peptide-receptive state. Together this ensemble of crystal structures provides insights into a distinct mechanism of tapasin-mediated peptide exchange. The catalytic chaperone tapasin assists peptide loading onto MHC-I molecules for antigen presentation and immune recognition. Here, the authors present crystal structures that provide insights into the molecular mechanism of tapasin-mediated peptide exchange. [ABSTRACT FROM AUTHOR] more...

Objective: Our previous work found COX4I2 was associated with angiogenesis in pheochromocytoma. The purpose of this study was to explore the role of COX4I2 in regulating angiogenesis in pheochromocytoma. Methods: Distribution of COX4I2 was evaluated by scRNA-seq in one case of pheochromocytoma and the findings were verified by immunostaining. COX4I2 was further knocked down in target cells. Changes of angiogenesisrelated genes were evaluated by qPCR in target cells. Results: The scRNA-seq revealed high mRNA expression of COX4I2 in fibroblasts rather than tumor cells. Immunostaining of COX4I2 confirmed its distribution in fibroblasts. Knocking down COX4I2 in NIH3T3 cell line led to significant reduction of angiogenesis-related genes, especially ANG1 and HGF. Conclusions: Fibroblasts mediate the angiogenesis of pheochromocytoma by increasing COX4I2 expression, possibly by affecting ANG1 and HGF. [ABSTRACT FROM AUTHOR] more...

Background: Chagas disease (CD) is caused by Trypanosoma cruzi and affects 6–7 million people worldwide. Approximately 30% of chronic patients develop chronic chagasic cardiomyopathy (CCC) after decades. Benznidazole (BNZ), one of the first-line chemotherapy used for CD, induces toxicity and fails to halt the progression of CCC in chronic patients. The recombinant parasite-derived antigens, including Tc24, Tc24-C4, TSA-1, and TSA-1-C4 with Toll-like receptor 4 (TLR-4) agonist-adjuvants reduce cardiac parasite burdens, heart inflammation, and fibrosis, leading us to envision their use as immunotherapy together with BNZ. Given genetic immunization (DNA vaccines) encoding Tc24 and TSA-1 induce protective immunity in mice and dogs, we propose that immunization with the corresponding recombinant proteins offers an alternative and feasible strategy to develop these antigens as a bivalent human vaccine. We hypothesized that a low dose of BNZ in combination with a therapeutic vaccine (TSA-1-C4 and Tc24-C4 antigens formulated with a synthetic TLR-4 agonist-adjuvant, E6020-SE) given during early chronic infection, could prevent cardiac disease progression and provide antigen-specific T cell immunity. Methodology/ Principal findings: We evaluated the therapeutic vaccine candidate plus BNZ (25 mg/kg/day/7 days) given on days 72 and 79 post-infection (p.i) (early chronic phase). Fibrosis, inflammation, and parasite burden were quantified in heart tissue at day 200 p.i. (late chronic phase). Further, spleen cells were collected to evaluate antigen-specific CD4+ and CD8+ T cell immune response, using flow cytometry. We found that vaccine-linked BNZ treated mice had lower cardiac fibrosis compared to the infected untreated control group. Moreover, cells from mice that received the immunotherapy had higher stimulation index of antigen-specific CD8+Perforin+ T cells as well as antigen-specific central memory T cells compared to the infected untreated control. Conclusions: Our results suggest that the bivalent immunotherapy together with BNZ treatment given during early chronic infection protects BALB/c mice against cardiac fibrosis progression and activates a strong CD8+ T cell response by in vitro restimulation, evidencing the induction of a long-lasting T. cruzi-immunity. Author summary: Chagas disease (CD) is a neglected tropical disease caused by the parasite Trypanosoma cruzi, transmitted through contact with infected feces of vectors bugs. CD can induce cardiac abnormalities including the development of fibrosis and eventually death. Benznidazole (BNZ) is the first-line drug approved against CD, however, its toxicity and lack of efficacy in the chronic phase have limited its use. Previous studies have demonstrated the feasibility of reducing doses of BNZ given in combination with therapeutic vaccines during the acute phase of CD, which increases its tolerability and reduces adverse side effects. Considering that patients are often diagnosed until more advanced stages of the disease, its necessary to evaluate therapies given in the chronic phase of CD. In this study, we evaluated a vaccine formulated with the recombinant T. cruzi-antigens TSA-1-C4 and Tc24-C4 and the adjuvant E6020-SE in combination with a low dose of BNZ given during the chronic phase of T. cruzi-infection using a murine model. The authors found that the combination therapy protects mice against cardiac fibrosis progression, allows the activation of a CD8+ T cell response, and induces a prolonged memory response against T. cruzi. This study supports the development of the vaccine-linked chemotherapy approach to prevent T. cruzi chronic infection. [ABSTRACT FROM AUTHOR] more...

Multisystem inflammatory syndrome in children (MIS-C) is a febrile pediatric inflammatory disease that may develop weeks after initial SARS-CoV-2 infection or exposure. MIS-C involves systemic hyperinflammation and multiorgan involvement, including severe cardiovascular, gastrointestinal (GI) and neurological symptoms. Some clinical attributes of MIS-C--such as persistent fever, rashes, conjunctivitis and oral mucosa changes (red fissured lips and strawberry tongue)--overlap with features of Kawasaki disease (KD). In addition, MIS-C shares striking clinical similarities with toxic shock syndrome (TSS), which is triggered by bacterial superantigens (SAgs). The remarkable similarities between MIS-C and TSS prompted a search for SAg-like structures in the SARS-CoV-2 virus and the discovery of a unique SAg-like motif highly similar to a Staphylococcal enterotoxin B (SEB) fragment in the SARS-CoV-2 spike 1 (S1) glycoprotein. Computational studies suggest that the SAg-like motif has a high affinity for binding T-cell receptors (TCRs) and MHC Class II proteins. Immunosequencing of peripheral blood samples from MIS-C patients revealed a profound expansion of TCR b variable gene 11-2 (TRBV11-2), which correlates withMIS-C severity and serum cytokine levels, consistent with a SAg-triggered immune response. Computational sequence analysis of SARS-CoV-2 spike further identified conserved neurotoxin-like motifs which may alter neuronal cell function and contribute to neurological symptoms in COVID-19 and MIS-C patients. Additionally, autoantibodies are detected during MIS-C, which may indicate development of post-SARS-CoV-2 autoreactive and autoimmune responses. Finally, prolonged persistence of SARS-CoV-2 RNA in the gut, increased gut permeability and elevated levels of circulating S1 have been observed in children with MIS-C. Accordingly, we hypothesize that continuous and prolonged exposure to the viral SAg-like and neurotoxin-like motifs in SARS-CoV-2 spike may promote autoimmunity leading to the development of postacute COVID-19 syndromes, including MIS-C and long COVID, as well as the neurological complications resulting from SARS-CoV-2 infection. [ABSTRACT FROM AUTHOR] more...

BACKGROUND: Transfusion-transmitted leishmaniasis is an increasing problem in areas where visceral and cutaneous leishmaniases are endemic. CASE REPORT: This article reports a case of transfusion-transmitted fatal visceral leishmaniasis (VL) caused by Leishmania (Leishmania) mexicana in a 42-year-old male resident of northwestern Colombia who after developing a terminal renal failure due to lupus nephritis received a renal transplant and multiple transfusions. RESULTS: Multiple intracellular Leishmania amastigotes were demonstrated in both renal biopsy and marrow aspirates. Cultures of the parasite were obtained in NNN medium and the identification of the species was done both by direct immunofluorescence and polymerase chain reaction-restriction fragment length polymorphism. CONCLUSIONS: This is the first report of a VL case produced by L. (L.) mexicana in Colombia, which usually is a dermotropic species. Our report suggests that although leishmaniasis is transmitted by the bite of phlebotomine sand flies, Leishmania parasite may be transmitted by blood transfusion, complicating the clinical course of organ transplant and being fatal. [ABSTRACT FROM AUTHOR] more...

Galectins are a family of proteins with at least one carbohydrate-recognition domain. Galectins are present in various tissues and organs and participate in different physiological and pathological molecular reactions in vivo. Wound healing is the basic process of traumatic disease recovery. Wound healing involves three overlapping stages: inflammation, proliferation, and remodelling. Furthermore, a comparison of wound healing with the tumour microenvironment revealed that galectin plays a key role in the wound healing process. The current review describes the role of galectin in inflammation, angiogenesis, re-epithelialisation, and fibrous scar formation and evaluates its potential as a therapeutic drug for wounds. [ABSTRACT FROM AUTHOR] more...

Galectin-3, a biomarker for heart failure (HF), has been associated with myocardial fibrosis. However, its causal involvement in HF pathogenesis has been questioned in certain models of cardiac injury-induced HF. To address this, we used desmin-deficient mice (des−/−), a model of progressive HF characterized by cardiomyocyte death, spontaneous inflammatory responses sustaining fibrosis, and galectin-3 overexpression. Genetic ablation or pharmacological inhibition of galectin-3 led to improvement of cardiac function and adverse remodeling features including fibrosis. Over the course of development of des−/− cardiomyopathy, monitored for a period of 12 months, galectin-3 deficiency specifically ameliorated the decline in systolic function accompanying the acute inflammatory phase (4-week-old mice), whereas a more pronounced protective effect was observed in older mice, including the preservation of diastolic function. Interestingly, the cardiac repair activities during the early inflammatory phase were restored under galectin-3 deficiency by increasing the proliferation potential and decreasing apoptosis of fibroblasts, while galectin-3 absence modulated macrophage–fibroblast coupled functions and suppressed both pro-fibrotic activation of cardiac fibroblasts and pro-fibrotic gene expression in the des−/− heart. In addition, galectin-3 also affected the emphysema-like comorbid pathology observed in the des−/− mice, as its absence partially normalized lung compliance. Collectively galectin-3 was found to be causally involved in cardiac adverse remodeling, inflammation, and failure by affecting functions of cardiac fibroblasts and macrophages. In concordance with this role, the effectiveness of pharmacological inhibition in ameliorating cardiac pathology features establishes galectin-3 as a valid intervention target for HF, with additive benefits for treatment of associated comorbidities, such as pulmonary defects. Schematic illustrating top to bottom, the detrimental role of galectin-3 (Gal3) in heart failure progression: desmin deficiency-associated spontaneous myocardial inflammation accompanying cardiac cell death (reddish dashed border) is characterized by infiltration of macrophages (round cells) and up-regulation of Lgals3 (encoding secretable galectin-3, green) and detrimental macrophage-related genes (Ccr2 and Arg1). In this galectin-3-enriched milieu, the early up-regulation of profibrotic gene expression (Tgfb1, Acta2, Col1a1), in parallel to the suppression of proliferative activities and a potential of senescence induction by cardiac fibroblasts (spindle-like cells), collectively promote des−/− cardiac fibrosis and dysfunction establishing heart failure (left panel). Additionally, galectin-3+ macrophage-enrichment accompanies the development of emphysema-like lung comorbidities. In the absence of galectin-3 (right panel), the effect of macrophage–fibroblast dipole and associated events are modulated (grey color depicts reduced expression or activities) leading to attenuated cardiac pathology in the des−/−Lgals3−/− mice. Pulmonary comorbidities are also limited. [ABSTRACT FROM AUTHOR] more...

In this study, the nanosized spherical erythromycin capped gold nanoparticles (eryth-Au(0)NPs) were fabricated for the first time. After that, multiple techniques such as UV-Visible, FTIR, HR-TEM, and XRD were used to examine the Au(0)NPs. Finally, these eryth-Au(0)NPs were employed for a wide range of applications, such as catalysis, antibacterial, and anticancer activities. The eryth-Au(0)NPs had shown remarkable catalytic activity as a catalyst in the ∼99% fragmentation of ibuprofen and paracetamol in one minute. They were also easily recovered from the reaction mixture and were reused seven times with increased catalytic potential. The excellent antimicrobial properties of Staphylococcus aureus (S. aureus) and Salmonella typhi (S. typhi) were also revealed using the well diffusion method. In addition, TLR expression levels in SKBR3 cells were measured using qReal-time PCR (qRT-PCR). TLR3 expression was upregulated in the SKBR3 breast cancer cell line, while TLR2, TLR4, TLR5, and TLR9 expression was downregulated. Furthermore, the simultaneous overexpression of p53 and downregulation of NF-kB demonstrated anticancer efficacy in breast cancer cells. The recent advancements can also be used to protect the aquatic environment from drugs toxicity in wastewater and antimicrobial and anticancer activities using a simple, cost-effective, fast, and efficient reduction/degradation technique based on the catalytic potential of eryth-Au(0)NPs. [ABSTRACT FROM AUTHOR] more...

Human roseolovirus U20 and U21 are type I membrane glycoproteins that have been implicated in immune evasion by interfering with recognition of classical and non-classical MHC proteins. U20 and U21 are predicted to be type I glycoproteins with extracytosolic immunoglobulin-like domains, but detailed structural information is lacking. AlphaFold and RoseTTAfold are next generation machine-learning-based prediction engines that recently have revolutionized the field of computational three-dimensional protein structure prediction. Here, we review the structural biology of viral immunoevasins and the current status of computational structure prediction algorithms. We use these computational tools to generate structural models for U20 and U21 proteins, which are predicted to adopt MHC-Ia-like folds with closed MHC platforms and immunoglobulin-like domains. We evaluate these structural models and place them within current understanding of the structural basis for viral immune evasion of T cell and natural killer cell recognition. [ABSTRACT FROM AUTHOR] more...

Natural products have been largely explored as treatments for leishmaniasis, neglected diseases with few toxic therapeutic options, as scaffolds for the development of new drugs. Herein, derivatives from the aerial parts of Baccharis trimera (Less.) DC (extract and its fractions) were evaluated against Leishmania amazonensis and macrophage cells. The ethyl acetate extract was fractionated by solid-phase extraction, resulting in eight fractions (F1-F8). Fractions F3-4 were further separated into 149 subfractions; subfraction 148 (IC50-PRO = 1.56 ± 0.1 μg mL−1) was selected for purification and constituent(s) characterization by high-performance liquid chromatography, as well as 1H and 13C nuclear magnetic resonance spectroscopy. The flavonoid eupatorin (3',5-dihydroxy-4',6,7-trimethoxyflavone) was identified. This compound was 3.7 times more effective against intracellular amastigotes (IC50-AMA = 1.6 ± 0.1 μM) than amphotericin B and presented low cytotoxicity (CC50 > 100 μM), being almost 62 times more selective for the parasite, showing great potential in drug development for cutaneous leishmaniasis treatment. [ABSTRACT FROM AUTHOR] more...

Parasites may significantly affect the functioning of the host organism including immune response and gut-brain-axis ultimately leading to alteration of the host behavior. The impact of intestinal worms on the host central nervous system (CNS) remains unexplored. The aim of this study was to evaluate the effect of intestinal infection by the tapeworm Hymenolepis diminuta on behavior and functions of the CNS in rats. The 3 months old animals were infected, and the effects on anxiety, exploration, sensorimotor skills and learning processes were assessed at 18 months in Open Field (OF), Novel Object Recognition (NOR) and the Water Maze (WM) tests. After completing the behavioral studies, both infected and non-infected rats were sacrificed, and the collected tissues were subjected to biochemical analysis. The levels of neurotransmitters, their metabolites and amino acids in selected structures of the CNS were determined by HPLC. In addition, the gene expression profile of the pro- and anti-inflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-10) was evaluated by Real-Time PCR to determine the immune response within the CNS to the tapeworm infection. The parasites caused significant changes in exploratory behavior, most notably, a reduction of velocity and total distance moved in the OF test; the infected rats exhibited decreased frequency in the central zone, which may indicate a higher level of anxiety. Additionally, parasite infestation improved spatial memory, assessed in the WM test, and recognition of new objects. These changes are related to the identified reduction in noradrenaline level in the CNS structures and less pronounced changes in striatal serotonergic neurotransmission. H. diminuta infestation was also found to cause a significant reduction of hippocampal expression of IL-6. Our results provide new data for further research on brain function during parasitic infections especially in relation to helminths and diseases in which noradrenergic system may play an important role. Author summary: Recent advances in the research on parasitic manipulation and/or control of the nervous system of their host resulted in the development of neuro-parasitology, a new and emerging branch of science. There have been advances in this area in relation to parasite-insect interactions or parasites directly invading central nervous system (CNS). However, the neuro-parasitology of parasitic infections in vertebrate hosts remains unexplored. In our study the effect of intestinal infection by the tapeworm on the behavior, neurotransmission and functions of the CNS in rats was evaluated. This infection positively influenced spatial memory and new object recognition. At the same time, the infected animals developed a greater level of anxiety and move more slowly. Behavioral changes were related to the reduction in noradrenaline level in the CNS structures, and less pronounced changes in striatal serotonergic neurotransmission. The results provide important data for the further progress in neuro-parasitology and our understanding of parasite-host interactions. In our opinion in the near future may turn out that the role of the intestinal host macrobiome in the CNS functioning may be just as significant as that of the microbiome. Presented neuro-immunological data provide a new perspectives for further studies on the CNS under intestinal parasite infection. The data of behavioral changes induced by active parasitic infection may be valid for explanations of the host-parasite relationship at the evolutionary level and their molecular adjustment. [ABSTRACT FROM AUTHOR] more...

Pregnancy can be defined a vascular event upon endocrine control. In the human hemo-chorial placentation the chorionic villi penetrate the wall of the uterine spiral arteries, to provide increasing amounts of nutrients and oxygen for optimal fetal growth. In any physiological pregnancy the natural maternal response is of a Th1 inflammatory type, aimed at avoiding blood loss through the arteriolar wall openings. The control of the vascular function, during gestation as in any other condition, is achieved through the action of two main types of prostanoids: prostaglandin E2 and thromboxane on the one hand (for vasoconstriction and coagulation), prostacyclin on the other (for vasodilation and blood fluidification). The control of the maternal immune response is upon the responsibility of the fetus itself. Indeed, the chorionic villi are able to counteract the natural maternal response, thus changing the inflammatory Th1 type into the anti-inflammatory Th2. Clinical and experimental research in the past half century address to inflammation as the leading cause of abortion, pregnancy loss, premature delivery and related pulmonary, cerebral, intestinal fetal syndromes. Increased level of Interleukin 6, Interleukin 1-beta, Tumor Necrosis Factor-alfa, Interferon-gamma, are some among the well-known markers of gestational inflammation. On the other side, COVID-19 pneumonia is a result of extensive inflammation induced by viral replication within the cells of the respiratory tract. As it may happen in the uterine arteries in the absence of an effective fetal control, viral pneumonia triggers pulmonary vascular coagulation. The cytokines involved in the process are the same as those in gestational inflammation. As the fetus breathes throughout the placenta, fetal death from placental thrombosis is similar to adult death from pulmonary thrombosis. Preventing and counteracting inflammation is mandatory in both conditions. The most relevant literature dealing with the above-mentioned concepts is reviewed in the present article. [ABSTRACT FROM AUTHOR] more...

With the continuous development of immunotherapy, researchers have paid more attention to the specific immune regulatory mechanisms of various immune responses in different diseases. As a novel and vital innate immune signal pathway, the cGAS-STING signal pathway activated by nucleic acid substances, interplays with other immune responses, by which it participates in regulating cancer, autoimmune and inflammatory diseases, microbial and parasitic infectious diseases, and other diseases. With the exception of its role in innate immunity, the growing list of researches demonstrated expanding roles of the cGAS-STING signal pathway in bridging the innate immunity (macrophage polarization) with the adaptive immunity (T lymphocytes differentiation). Macrophages and T lymphocytes are the most representative cells of innate immunity and adaptive immunity, respectively. Their polarization or differentiation are involved in the pathogenesis and progression of various diseases. Here we mainly summarized recent advanced discoveries of how the cGAS-STING signal pathway regulated macrophages polarization and T lymphocytes differentiation in various diseases and vaccine applications, providing a promising direction for the development and clinical application of immunotherapeutic strategies for related diseases. [ABSTRACT FROM AUTHOR] more...

Bacteria sense intracellular and environmental signals using an array of proteins as antennas. The information is transmitted from such sensory modules to other protein domains that act as output effectors. Sensor and effector can be part of the same polypeptide or instead be separate diffusible proteins that interact specifically. The output effector modules regulate physiologic responses, allowing the cells to adapt to the varying conditions. These biological machineries are known as signal transduction systems (STSs). Despite the captivating architectural diversity exhibited by STS proteins, a universal feature is their allosteric regulation: signal binding at one site modifies the activity at a physically distant site. Allostery requires protein plasticity, precisely encoded within their 3D structures, and implicating programmed molecular motions. This review summarizes how STS proteins connect stimuli to specific responses by exploiting allostery and protein plasticity. Illustrative examples spanning a wide variety of protein folds will focus on one- and two-component systems (TCSs). The former encompass the entire transmission route within a single polypeptide, whereas TCSs have evolved as separate diffusible proteins that interact specifically, sometimes including additional intermediary proteins in the pathway. Irrespective of their structural diversity, STS proteins are able to modulate their own molecular motions, which can be relatively slow, rigid-body movements, all the way to fast fluctuations in the form of macromolecular flexibility, thus spanning a continuous protein dynamics spectrum. In sum, STSs rely on allostery to steer information transmission, going from simple two-state switching to rich multi-state conformational order/disorder transitions. [ABSTRACT FROM AUTHOR] more...