Host-microbe interaction & Vascular Dysfunction
Using human samples and novel genetically modified mice, we have been showing how the absence of the protein Caveolin-1 (Cav-1) modulates the inflammatory response and changes the normal function of lung endothelial cells (EC) during PAH. In particular, our work uncovered how Cav-1 deficiency leads to dysfunction of a major EC enzyme, eNOS, and depletion of the antiproliferative receptor BMPR2, contributing to lung vascular disease (Oliveira et al., 2017; Oliveira & Minshall, 2018). Our work has been critical to show the relationship between Cav-1 and eNOS and how it impacts BMPR2/TGF-β signaling (Chen, Oliveira, et al., 2018; Oliveira et al., 2017; Potje et al., 2017) and also how pathogen-induced EC injury play a key role in the onset of PAH (Oliveira, 2022).
Representative confocal micrography showing a remodeled pulmonary artery during pulmonary arterial hypertension (PAH). Immunohistochemistry was used to investigate the expression of Caveolin-1 (red) in CD31+ endothelial cells (green). Nuclei were stained using DAPI (blue).
Adult Schistosoma mansoni attached to a primary culture of mesenteric endothelial cells.
Sepsis & Innate Immunity
We also are interested in collaborative research on the role of pharmaceutical compounds in sepsis. Sepsis is a severe illness that leads to more than 200,000 deaths/year. One key characteristic of sepsis is the systemic hypotension caused by the presence of bacteria and its toxins in the blood vessels. In this sense, we observed that the volatile anesthetic sevoflurane potentiates macrophage bactericidal and anti-inflammatory response in endotoxemia, which lays the foundation of new knowledge to possibly improve the survival of septic patients (Gerber et al., 2019). We also showed how the key purinergic enzyme CD39 modulates the function of the P2X7R in macrophages and thus, attenuates sepsis-induced liver injury (Savio et al., 2017). Moreover, we contributed to test the effect of pharmaceutical compounds (Esparza et al., 2022 – in prep.) and a novel probe (Colucci-Guyon et al., 2019; Batista, Oliveira, et al., 2022) on sepsis and as a novel research tool for leishmaniosis and neutrophil-related research, respectively.
Illustrative photo of anesthetics (left side). P2X7 receptor expression in lipopolysaccharide (LPS)-activated peritoneal macrophages (right side).
Endothelial-immune cell crosstalk via EVs
Our recent work found that depletion of lung EC-Cav-1 is traceable in the plasma from human PAH patients as a component of extracellular vesicles (EVs). EVs are cell membrane-derived structures released under physiological and pathological conditions. EV shedding and its specific cell-derived cargo have been implicated in several inflammatory diseases, including pulmonary diseases. In line with those observations, our exciting data shows that EC-derived Cav-1+ EVs contribute to pro-fibrotic macrophage activation and vascular remodeling (Oliveira et al., 2019; 2022 – in prep). Thus, identifying how EC-EC and EC-immune cell communication via EVs leads to pulmonary vascular remodeling is an important step for research on reducing mortality and morbidity during PAH.
Representative confocal micrography showing endothelial cells (green) using a novel genetically modified animal model to investigate endothelial phenotypes and extracellular vesicle shedding. Nuclei were stained using DAPI (blue). Other lung cell types are observed in red (mTomato).
Plasma extracellular Vesicles loaded into a Nanoparticle Analyzer (NanoSight).
Purinergic Signaling & Inflammation
During my graduate research, for the first time, I identified the expression and function of the damage-associated molecular pattern receptors called P2X7 (massive ATP-activated receptors) on mesentery ECs and how losing the expression of these receptors critically impairs the purinergic signaling and NO production by ECs (Oliveira et al., 2013, 2016). We also observed that in the chronic stage of schistosomiasis, a defect in the function of P2X7 receptors on macrophages was associated with TGF-β production, a regulatory and pro-fibrotic cytokine (Oliveira et al., 2014). I recently also helped to identify that defective P2X7R signaling is regulated via a Cav-1-dependent mechanism (Savio et al., 2020), which may be a key step for schistosomiasis-induced inflammation. Although some anti-parasitic treatments are available against schistosomiasis, they are ineffective in fully recovering the inflammatory damage associated with the disease. Moreover, no targeted therapy exists for S. mansoni-associated lung disease.
Fluorescent micrograph showing the murine mesentery (left side). Intracellular Calcium measurement in peritoneal macrophages (right side).
“At the University we teach because we research”
By Carlos Chagas Filho, a Brazilian physician, biologist, and scientist.