Claudia Lucia Martins Silva

Schistosomiasis, a complex chronic intravascular parasitic disease caused by Schistosoma mansoni , triggers a multifaceted host immune response and drives endothelial cells toward a sustained proinflammatory phenotype. The dysfunctional endothelial cells are a hallmark event that contributes to intestinal and liver damage mainly due to an increased monocyte adhesion, but the elevated morbidity unveils the lack of knowledge about disease pathogenesis. Purinergic P2Y ₆ receptor (P2Y ₆ R) expression is induced in some inflammatory models; therefore, we hypothesized that endothelial P2Y ₆ R contributes to monocyte adhesion and mesenteric inflammation in S. mansoni -infected mice. Our results show that, unlike control mice, P2Y ₆ R stimulation failed to enhance monocyte adhesion to endothelial cells from infected animals. Molecular analyses using RT-qPCR and immunocytochemistry revealed significant downregulation of P2Y ₆ R expression in endothelial cells from the infected group at both transcript and protein levels. Importantly, pretreatment with a proteasome inhibitor restored both P2Y ₆ R expression and function, implicating proteasomal degradation as a key mechanism underlying receptor loss during infection. Elevated lipid peroxidation in endothelial cells from the infected group further supported a role for reactive oxygen species (ROS)-dependent proteasome activation and receptor degradation. Collectively, these findings suggest that infection selectively modulates P2Y ₆ R signaling by promoting proteasome-dependent downregulation of P2Y ₆ R in endothelial cells, which could be an adaptive mechanism to reduce mesenteric inflammation and limit host tissue damage and morbidity during chronic infection. Graphical Abstract

Portosystemic and mesocaval shunts are aberrant vascular connections that bypass hepatic detoxification process, directly linking the portal to the systemic circulation. These shunts, whether congenital or acquired, might play a pivotal role in the pathogenesis of systemic inflammatory diseases, such as schistosomiasis-associated pulmonary hypertension (Sch-PH) by facilitating the dissemination of pathogen-derived eggs and antigens from the gut and mesentery into the lungs. Beyond the translocation of Schistosoma mansoni eggs, emerging evidence implicates that gut-lung microbiome dysbiosis contributes to the development of pulmonary hypertension (PH) in the preclinical animal model of Sch-PH. Sch-PH emerges as a chronic complication of schistosomiasis and evolves silently, progressively increasing the mean pulmonary arterial pressure and vascular resistance, leading to right heart hypertrophy, failure, and significant morbidity and mortality. Chronic schistosomiasis is often linked to the development of portal hypertension, which significantly contributes to the formation of the porto/mesocaval shunt as a compensatory response that can have far-reaching implications on pulmonary vascular physiology. In addition, portal hypertension compromises the integrity of the intestinal barrier, exacerbating peritoneal and mesenteric inflammation, potentially facilitating microbial and metabolite entrance into the systemic circulation. This article briefly discusses the mechanisms by which porto/mesocaval shunts contribute to PH, especially Group I PH, focusing on the interplay between portosystemic shunting, microbial translocation, and systemic dissemination of proinflammatory metabolites.

Este estudo de caso analisou relatos de cinco professores universitários, da área das ciências biomédicas, sobre suas experiências pedagógicas durante o ensino remoto, devido à pandemia de COVID-19 e discutiu a perspectiva do ensino híbrido na formação em saúde. Duas questões principais nortearam o estudo: Como estes docentes se adaptaram e ressignificaram suas práticas educativas a partir da realidade imposta pelo ensino remoto? Como as reflexões dos docentes podem servir de base para mudanças nas práticas educativas destes professores na perspectiva do ensino híbrido no período pós-pandêmico? Três principais categorias emergiram da análise de conteúdo das falas destes professores: 1- relações pedagógicas - levaram em conta as diversas condições de acesso e estudo e foram pautadas em comunicação construtiva e acolhedora; 2- metodologias e estratégias pedagógicas - centraram-se na participação dos estudantes, na contextualização dos conteúdos e na criação de atividades práticas alternativas e 3- avaliação pedagógica - foi compreendida como inerente ao processo de aprendizagem, adotou-se estratégias diversificadas e o acompanhamento dos alunos foi realizado ao longo de toda a disciplina. As tecnologias digitais atuaram como elo articulador e transversal entre relações pedagógicas, estratégias de ensino e avaliação. Os resultados apontam que, apesar de dificuldades, o grupo de docentes foi capaz de construir um novo repertório e vislumbrar possibilidades de integração das estratégias em suas práticas futuras. Desse modo, os resultados contribuem para ampliar a discussão sobre o hibridismo como perspectiva educacional para a formação superior na área da saúde. Neste momento pós-pandêmico é relevante que se continue a discutir os impactos, desafios e aprendizados vivenciados, identificando e analisando a contribuição das experiências da comunidade universitária para projetar mudanças construtivas e sustentáveis nos processos de ensino-aprendizagem.

Schistosomiasis is an intravascular infectious disease that impacts over 200 million people globally. In its chronic stage, it leads to mesenteric inflammation with significant involvement of monocytes/macrophages. Endothelial cells lining the vessel lumens play a crucial role, and mount of evidence links this disease to a downregulation of endoprotective cell signaling favoring a primed and proinflammatory endothelial cell phenotype and therefore the loss of immunovascular homeostasis. One hallmark of infectious and inflammatory conditions is the release of nucleotides into the extracellular milieu, which, in turn, act as innate messengers, activating purinergic receptors and triggering cell-to-cell communication. ATP influences the progression of various diseases through P2X and P2Y purinergic receptor subtypes. Among these receptors, P2Y₂ (P2Y₂R) and P2X7 (P2X7R) receptors stand out, known for their roles in inflammation. However, their specific role in schistosomiasis has remained largely unexplored. Therefore, we hypothesized that endothelial P2Y₂R and P2X7R could contribute to monocyte adhesion to mesenteric endothelial cells in schistosomiasis. Using a preclinical murine model of schistosomiasis associated with endothelial dysfunction and age-matched control mice, we showed that endothelial P2Y₂R and P2X7R activation increased monocyte adhesion to cultured primary endothelial cells in both groups. However, a distinct upregulation of endothelial P2Y₂R-driven canonical Ca²⁺ signaling was observed in the infected group, amplifying adhesion. In the control group, the coactivation of endothelial P2Y₂R and P2X7R did not alter the maximal monocyte adhesion induced by each receptor individually. However, in the infected group, this coactivation induced a distinct upregulation of P2Y₂R-P2X7R-driven canonical signaling, IL-1β release, and VCAM-1 expression, with underlying mechanisms involving inflammasome and NF-κB signaling. Therefore, current data suggest that schistosomiasis alters endothelial cell P2Y₂R/P2X7R signaling during inflammation. These discoveries advance our understanding of schistosomiasis. This intricate interplay, driven by PAMP-triggered endothelial P2Y₂R/P2X7R cross-talk, emerges as a potential key player in the mesenteric inflammation during schistosomiasis.

In mice, oral Toxoplasma gondii infection induces severe ileitis. The aim of the present study was to investigate the impact of the P2X7 receptor (P2X7) on the inflammatory response to T. gondii-induced ileitis. Cysts of the ME49 strain of T. gondii were used to induce ileitis. The infected mice were euthanized on day 8 and ileal tissue and peripheral blood were collected for histopathological and immunohistochemical analyses. Ileal contractility, inflammatory mediators, inflammasome activation, quantitative PCR analysis of gene expression, and fecal microbiota were assessed using appropriate techniques, respectively. The infected P2X7−/− mice had greater disease severity, parasitic burden, liver damage, and intestinal contractility than the infected wild-type (WT) mice. Infection increased serum IL-6 and IFN-γ and tissue caspase-1 but not NLRP3 in P2X7−/− mice compared to WT mice. Bacteroidaceae, Rikenellaceae, and Rhodospirillales increased while Muribaculaceae and Lactobacillaceae decreased in the infected WT and P2X7−/− mice. Bacteroidia and Tannerellaceae increased in the P2X7−/− mice with ileitis. By contrast, Clostridiales and Mollicutes were absent in the P2X7−/− mice but increased in the WT mice. P2X7 protects mice against T. gondii infection by activating the inflammasome and regulating the local and systemic immune responses. Specific gut bacterial populations modulated by P2X7 determine disease severity.

In critically ill patients with acute respiratory distress syndrome (ARDS) coronavirus disease 2019 (COVID-19), a high incidence of thromboembolic and hemorrhagic events is reported. COVID-19 may lead to impairment of the coagulation cascade, with an imbalance in platelet function and the regulatory mechanisms of coagulation and fibrinolysis. Clinical manifestations vary from a rise in laboratory markers and subclinical microthrombi to thromboembolic events, bleeding, and disseminated intravascular coagulation. After an inflammatory trigger, the mechanism for activation of the coagulation cascade in COVID-19 is the tissue factor pathway, which causes endotoxin and tumor necrosis factor-mediated production of interleukins and platelet activation. The consequent massive infiltration of activated platelets may be responsible for inflammatory infiltrates in the endothelial space, as well as thrombocytopenia. The variety of clinical presentations of the coagulopathy confronts the clinician with the difficult questions of whether and how to provide optimal supportive care. In addition to coagulation tests, advanced laboratory tests such as protein C, protein S, antithrombin, tissue factor pathway inhibitors, D-dimers, activated factor Xa, and quantification of specific coagulation factors can be useful, as can thromboelastography or thromboelastometry. Treatment should be tailored, focusing on the estimated risk of bleeding and thrombosis. The aim of this review is to explore the pathophysiology and clinical evidence of coagulation disorders in severe ARDS-related COVID-19 patients.

Schistosomiasis is a neglected tropical disease. It is related to long-lasting granulomatous fibrosis and inflammation of target organs, and current sub-optimal pharmacological treatment creates global public health concerns. Intravascular worms and eggs release antigens and extracellular vesicles that target host endothelial cells, modulate the immune system, and stimulate the release of damageassociated molecular patterns (DAMPs). ATP, one of the most studied DAMPs, triggers a cascade of autocrine and paracrine actions through purinergic P2X and P2Y receptors, which are shaped by ectonucleotidases (CD39). Both P2 receptor families, and in particular P2Y1, P2Y2, P2Y12, and P2X7 receptors, have been attracting increasing interest in several inflammatory diseases and drug development. Current data obtained from the murine model unveiled a CD39-ADP-P2Y1/P2Y12 receptors signaling pathway linked to the liver and mesenteric exacerbations of schistosomal inflammation. Therefore, we proposed that members of this purinergic signaling could be putative pharmacological targets to reduce schistosomal morbidity.

Leishmaniasis is a neglected tropical disease caused by an intracellular parasite of the genus Leishmania. Damage-associated molecular patterns (DAMPs) such as UTP and ATP are released from infected cells and, once in the extracellular medium, activate P2 purinergic receptors. P2Y₂ and P2X7 receptors cooperate to control Leishmania amazonensis infection. NLRP3 inflammasome activation and IL-1β release resulting from P2X7 activation are important for outcomes of L. amazonensis infection. The cytokine IL-1β is required for the control of intracellular parasites. In the present study, we investigated the involvement of the P2Y₂ receptor in the activation of NLRP3 inflammasome elements (caspase-1 and 11) and IL-1β secretion during L. amazonensis infection in peritoneal macrophages as well as in a murine model of cutaneous leishmaniasis. We found that 2-thio-UTP (a selective P2Y₂ agonist) reduced parasite load in L. amazonensis-infected murine macrophages and in the footpads and lymph nodes of infected mice. The antiparasitic effects triggered by P2Y₂ activation were not observed when cells were pretreated with a caspase-1 inhibitor (Z-YVAD-FMK) or in macrophages from caspase-1/11 knockout mice (CASP-1,11^−/−). We also found that UTP treatment induced IL-1β secretion in wild-type (WT) infected macrophages but not in cells from CASP-1,11^−/− mice, suggesting that caspase-1 activation by UTP triggers IL-1β secretion in L. amazonensis-infected macrophages. Infected cells pretreated with IL-1R antagonist did not show reduced parasitic load after UTP and ATP treatment. Our in vivo experiments also showed that intralesional UTP treatment reduced both parasite load (in the footpads and popliteal lymph nodes) and lesion size in wild-type (WT) and CASP-11^−/− but not in CASP-1,11^−/− mice. Taken together, our findings suggest that P2Y₂R activation induces CASP-1 activation and IL-1β secretion during L. amazonensis infection. IL-1β/IL-1R signaling is crucial for P2Y₂R-mediated protective immune response in an experimental model of cutaneous leishmaniasis.