The Oxidative Stress and Chronic Inflammatory Process in Chagas Disease: Role of Exosomes and Contributing Genetic Factors

Microencapsulation of Theobroma cacao L polyphenols: A high-value approach with in vitro anti-Trypanosoma cruzi, immunomodulatory and antioxidant activities

Chagas disease (CHD) is the highest economic burden parasitosis worldwide and the most important cardiac infection, without therapeutic alternatives to halt or reverse its progression. In CHD-experimental models, antioxidant and anti-inflammatory compounds have demonstrated therapeutic potential in cardiac dysfunction. Theobroma cacao polyphenols are potent natural antioxidants with cardioprotective and anti-inflammatory action, which are susceptible to degradation, requiring technological approaches to guarantee their protection, stability, and controlled release. Here, 21 cocoa polyphenol-rich microencapsulates were produced by spray-drying and freeze-drying techniques using two wall materials (maltodextrin and gum arabic). Chemical (total and individual phenolic content and antioxidant activity), structural (morphology), and biological parameters (cytotoxicity, trypanocidal, antioxidant, and immunomodulatory activities) were assessed to determine the most efficient microencapsulation conditions on Trypanosoma cruzi-infected myocardioblast and macrophage cells. Significant antiproliferative properties against infected cells (superior to benznidazole) were found in two microencapsulates which also exhibited cardioprotective properties against oxidative stress, inflammation, and cell death.

Helicobacter pylori infection selectively attenuates endothelial function in male mice via exosomes-mediated ROS production

Background

Substantial sex differences exist in atherosclerosis. Excessive reactive oxygen species (ROS) formation could lead to endothelial dysfunction which is critical to atherosclerosis development and progression. Helicobacter pylori (H. pylori) infection has been shown to attenuate endothelial function via exosomes-mediated ROS formation. We have demonstrated that H. pylori infection selectively increases atherosclerosis risk in males with unknown mechanism(s). The present study was to test the hypothesis that H. pylori infection impaired endothelial function selectively in male mice through exosome-mediated ROS formation.

Methods and results

Age-matched male and female C57BL/6 mice were infected with CagA+ H. pylori to investigate sex differences in H. pylori infection-induced endothelial dysfunction. H. pylori infection attenuated acetylcholine (ACh)-induced endothelium-dependent aortic relaxation without changing nitroglycerine-induced endothelium-independent relaxation in male but not female mice, associated with increased ROS formation in aorta compared with controls, which could be reversed by N-acetylcysteine treatment. Treatment of cultured mouse brain microvascular endothelial cells with exosomes from H. pylori infected male, not female, mice significantly increased intracellular ROS production and impaired endothelial function with decreased migration, tube formation, and proliferation, which could be prevented with N-acetylcysteine treatment.

Conclusions

H. pylori infection selectively impairs endothelial function in male mice due to exosome-mediated ROS formation.

Extracellular vesicles: an emerging player in retinal homeostasis

Extracellular vesicles (EVs) encompass secreted membrane vesicles of varied sizes, including exosomes (-30-200 nm) and microvesicles (MVs) that are ∼100-1,000 nm in size. EVs play an important role in autocrine, paracrine, and endocrine signaling and are implicated in myriad human disorders including prominent retinal degenerative diseases, like age related macular degeneration (AMD) and diabetic retinopathy (DR). Studies of EVs in vitro using transformed cell lines, primary cultures, and more recently, induced pluripotent stem cell derived retinal cell type(s) (e.g., retinal pigment epithelium) have provided insights into the composition and function of EVs in the retina. Furthermore, consistent with a causal role of EVs in retinal degenerative diseases, altering EV composition has promoted pro-retinopathy cellular and molecular events in both in vitro and in vivo models. In this review, we summarize the current understanding of the role of EVs in retinal (patho)physiology. Specifically, we will focus on disease-associated EV alterations in specific retinal diseases. Furthermore, we discuss the potential utility of EVs in diagnostic and therapeutic strategies for targeting retinal diseases.

Extracellular vesicles in the context of Chagas Disease - A systematic review

Extracellular vesicle (EVs) traffic is considered an important cellular communication process between cells that can be part of a single organism or belong to different living beings. The relevance of EV-mediated cellular communication is increasingly studied and appreciated, especially in relation to pathological conditions, including parasitic disorders, in which the EV release and uptake processes have been documented. In the context of Chagas Disease (CD), EVs have been explored, however, current data have not been systematically revised in order to provide an overview of the published literature and the main results obtained thus far. In this systematic review, 25 studies involving the investigation of EVs in CD were identified. The studies involved Trypanosoma cruzi (Tc)-derived EVs (Tc-EVs), as well as EVs derived from T. cruzi-infected mammalian cells-derived EVs, mainly isolated by ultracentrifugation and poorly characterized. The objectives of the identified studies included the characterization of the protein and RNA cargo of Tc-EVs, as well as investigation of EVs in parasitic infections and immune-related processes. Overall, our systematic review reveals that EVs play critical roles in several mechanisms related to the interaction between T. cruzi and mammalian hosts, their contribution to immune system evasion by the parasite, and to chronic inflammation in the host. Future studies will benefit from the consolidation of isolation and characterization methods, as well as the elucidation of the role of EVs in CD.

The roles of COX-2 in protozoan infection

Protozoan diseases cause great harm in animal husbandry and require human-provided medical treatment. Protozoan infection can induce changes in cyclooxygenase-2 (COX-2) expression. The role played by COX-2 in the response to protozoan infection is complex. COX-2 induces and regulates inflammation by promoting the synthesis of different prostaglandins (PGs), which exhibit a variety of biological activities and participate in pathophysiological processes in the body in a variety of ways. This review explains the roles played by COX-2 in protozoan infection and analyzes the effects of COX-2-related drugs in protozoan diseases.

Genome-wide association study for Chagas Cardiomyopathy identify a new risk locus on chromosome 18 associated with an immune-related protein and transcriptional signature

BACKGROUND

Chronic Chagas Cardiomyopathy (CCC) usually develops between 10 and 20 years after the first parasitic infection and is one of the leading causes of end-stage heart failure in Latin America. Despite the great inter-individual variability in CCC susceptibility (only 30% of infected individuals ever present CCC), there are no known predictors for disease development in those chronically infected.

METHODOLOGY/PRINCIPAL FINDINGS

We describe a new susceptibility locus for CCC through a GWAS analysis in the SaMi-Trop cohort, a population-based study conducted in a Chagas endemic region from Brazil. This locus was also associated with CCC in the REDS II Study. The newly identified locus (rs34238187, OR 0.73, p-value 2.03 x 10-9) spans a haplotype of approximately 30Kb on chromosome 18 (chr18: 5028302-5057621) and is also associated with 80 different traits, most of them blood protein traits significantly enriched for immune-related biological pathways. Hi-C data show that the newly associated locus is able to interact with chromatin sites as far as 10Mb on chromosome 18 in a number of different cell types and tissues. Finally, we were able to confirm, at the tissue transcriptional level, the immune-associated blood protein signature using a multi-tissue differential gene expression and enrichment analysis.

CONCLUSIONS/SIGNIFICANCE

We suggest that the newly identified locus impacts CCC risk among T cruzi infected individuals through the modulation of a downstream transcriptional and protein signature associated with host-parasite immune response. Functional characterization of the novel risk locus is warranted.

Platelets, Macrophages, and Thromboinflammation in Chagas Disease

Chagas disease (CD) is a major health problem in the Americas and an emerging health problem in Europe and other nonendemic countries. Several studies have documented persistence of the protozoan parasite Trypanosoma cruzi, and oxidative and inflammatory stress are major pathogenic factor. Mural and cardiac thrombi, cardiac arrhythmias, and cardiomyopathy are major clinical features of CD. During T. cruzi infection, parasite-released factors induce endothelial dysfunction along with platelet (PLT) and immune-cell activation. PLTs have a fundamental role in maintaining hemostasis and preventing bleeding after vascular injury. Excessive activation of PLTs and coagulation cascade can result in thrombosis and thromboembolic events, which are recognized to occur in seropositive individuals in early stages of CD when clinically symptomatic heart disease is not apparent. Several host and parasite factors have been identified to signal hypercoagulability and increase the risk of ischemic stroke in early phases of CD. Further, PLT interaction with immune cells and their role in host defense against pathogens and inflammatory processes have only recently been recognized and evolving. In the context of parasitic diseases, PLTs function in directly responding to T. cruzi infection, and PLT interactions with immune cells in shaping the proinflammatory or immunoregulatory function of monocytes, macrophages, and neutrophils remains elusive. How T. cruzi infection alters systemic microenvironment conditions to influence PLT and immune-cell interactions is not understood. In this review, we discuss the current literature, and extrapolate the mechanistic situations to explain how PLT and innate immune cell (especially monocytes and macrophages) interactions might be sustaining hypercoagulability and thromboinflammation in chronic CD.

Discovery of novel drugs for Chagas disease: is carbonic anhydrase a target for antiprotozoal drugs?

INTRODUCTION

Carbonic anhydrase (CA) arose significant interest as a potential new target for Chagas disease since its discovery in Trypanosoma cruzi in 2013. Benznidazole and Nifurtimox have been used for Chagas disease treatment for 60 years despite all efforts done for obtaining more efficient treatments, acting in the acute and chronic phases of illness, with fewer side effects and resistance induction.

AREAS COVERED

We discuss the positive and negative aspects of T. cruzi CA (TcCA) studies as a target for developing new drugs. The current research discoveries and the classes of TcCA inhibitors are reviewed. The sulfonamides and their derivatives are the main inhibitor classes, but hydroxamates and the thiols, were investigated too. These compounds inhibited the growth of the evolutive forms of the parasite. A comparative analysis was done with CAs from other Trypanosomatids and protozoans.

EXPERT OPINION

The search for new targets and drugs is a significant challenge worldwide, and TcCA is a potential candidate for developing new drugs. Several studied inhibitors were active against Trypanosoma cruzi, but their penetration and toxicity problems emerged. New approaches are in progress to obtain inhibitors with desired properties, allowing further steps such as tests using an adequate animal model and subsequent developments for the preclinical testing.

Cellular Stress and Senescence Induction during Trypanosoma cruzi Infection

Chagas disease (CD) is a neglected tropical disease caused by Trypanosoma cruzi infection that, despite being discovered over a century ago, remains a public health problem, mainly in developing countries. Since T. cruzi can infect a wide range of mammalian host cells, parasite–host interactions may be critical to infection outcome. The intense immune stimulation that helps the control of the parasite’s replication and dissemination may also be linked with the pathogenesis and symptomatology worsening. Here, we discuss the findings that support the notion that excessive immune system stimulation driven by parasite persistence might elicit a progressive loss and collapse of immune functions. In this context, cellular stress and inflammatory responses elicited by T. cruzi induce fibroblast and other immune cell senescence phenotypes that may compromise the host’s capacity to control the magnitude of T. cruzi-induced inflammation, contributing to parasite persistence and CD progression. A better understanding of the steps involved in the induction of this chronic inflammatory status, which disables host defense capacity, providing an extra advantage to the parasite and predisposing infected hosts prematurely to immunosenescence, may provide insights to designing and developing novel therapeutic approaches to prevent and treat Chagas disease.

Isoliquiritigenin Ameliorates Ischemia-Induced Myocardial Injury via Modulating the Nrf2/HO-1 Pathway in Mice

Background

Oxidative stress and inflammatory reaction play critical roles in acute myocardial infarction (AMI). Isoliquiritigenin (ISL), a flavonoid monomer extracted from licorice, has been found to have antioxidant and anti-inflammatory effects in cancer studies. Here, we tested the effect and underlying mechanisms of ISL on ischemia-induced myocardial injury in a mouse AMI model.

Methods

Adult C57BL/6 mice were pre-treated by intraperitoneal injection of ISL and/or a specific nuclear factor E2-related factor 2 (Nrf2) inhibitor ML385 for 3 days, respectively. Then, the AMI model was established by ligating the anterior descending branch of the left coronary artery. Myocardial oxidative stress status, inflammatory response, cardiac function and infarction size were assessed after 7th day of surgery.

Results

Compared with sham group, the reactive oxygen species (ROS) and malondialdehyde (MDA) level in AMI group were significantly increased. However, the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) level were dramatically decreased. ISL treatment significantly reduced the myocardial infarction area, improved cardiac function, inhibited the production of ROS and MDA and reduced the consumption of SOD and GSH-Px. Interestingly, ISL could significantly increase nuclear Nrf2 and cytosolic heme oxygenase 1 (HO-1) level in the infarcted myocardium and reduce the oxidative stress after AMI. Also, ISL treatment dramatically inhibited the activation of myocardial NF-κB pathway and reduced the expression of pro-inflammatory factors in the AMI group. However, the administration of ML385 not only suppressed the Nrf2/HO-1 activation, the anti-oxidant and anti-inflammatory effects induced by ISL, but also attenuated the beneficial role of ISL on reducing infarct size and improving cardiac function in the mouse with AMI.

Conclusion

The results suggested that activation of Nrf2/HO-1 pathway has an essential role in ISL-induced cardiac protection by alleviating myocardial oxidative stress and inflammation response in mice with AMI.