Effects of Acute and Chronic Trypanosoma cruzi Infection on Pregnancy Outcomes in Mice: Parasite Transmission, Mortality, Delayed Growth, and Organ Damage in Pups.

Chagas disease is caused by Trypanosoma cruzi. This study aimed to determine the effects of T. cruzi infection on fertility rate and health of the newborn pups in pregnant mice. Female mice were challenged with T. cruzi and mated at 21 days (acute parasitemic phase) or 90 days (chronic parasite persistence phase) after infection. Pups were examined for growth up to 20 days after birth; and parasite burden in brain, heart, skeletal muscle, and intestine was measured by real-time quantitative PCR. The inflammatory infiltrate, necrosis, and fibrosis in pups' heart and brain tissues were evaluated by histology. T. cruzi infection in dams delayed the onset of pregnancy, decreased the fertility rate, and led to vertical transmission of parasite to the pups. Furthermore, infected dams delivered pups that exhibited decreased survival rate, decreased birth weight, and decreased growth rate. Significantly increased inflammation, necrosis, and fibrosis of cardiac and brain tissues were noted in pups born to infected dams. Initial challenge with higher parasite dose had more detrimental effects on fertility rate and pups' health in both acutely and chronically infected dams. In conclusion, mice offer a promising model to evaluate the efficacy of new vaccines and therapeutic drugs in controlling the acute and chronic maternal T. cruzi infection and congenital transmission to newborns, and in improving the fertility rate and pups' health outcomes.

Poly(ADP-ribose) polymerase 1 regulates mitochondrial DNA repair in an NAD-dependent manner.

Mitochondrial DNA is located in organelle that house essential metabolic reactions and contains high reactive oxygen species. Therefore, mitochondrial DNA suffers more oxidative damage than its nuclear counterpart. Formation of a repair enzyme complex is beneficial to DNA repair. Recent studies have shown that mitochondrial DNA polymerase (Pol γ) and poly(ADP-ribose) polymerase 1 (PARP1) were found in the same complex along with other mitochondrial DNA repair enzymes, and mitochondrial PARP1 level is correlated with mtDNA integrity. However, the molecular basis for the functional connection between Pol γ and PARP1 has not yet been elucidated because cellular functions of PARP1 in DNA repair are intertwined with metabolism via NAD+ (nicotinamide adenosine dinucleotide), the substrate of PARP1, and a metabolic cofactor. To dissect the direct effect of PARP1 on mtDNA from the secondary perturbation of metabolism, we report here biochemical studies that recapitulated Pol γ PARylation observed in cells and showed that PARP1 regulates Pol γ activity during DNA repair in a metabolic cofactor NAD+ (nicotinamide adenosine dinucleotide)-dependent manner. In the absence of NAD+, PARP1 completely inhibits Pol γ, while increasing NAD+ levels to a physiological concentration that enables Pol γ to resume maximum repair activity. Because cellular NAD+ levels are linked to metabolism and to ATP production via oxidative phosphorylation, our results suggest that mtDNA damage repair is coupled to cellular metabolic state and the integrity of the respiratory chain.

Proinflammatory Effects of Respiratory Syncytial Virus-Induced Epithelial HMGB1 on Human Innate Immune Cell Activation.

High mobility group box 1 (HMGB1) is a multifunctional nuclear protein that translocates to the cytoplasm and is subsequently released to the extracellular space during infection and injury. Once released, it acts as a damage-associated molecular pattern and regulates immune and inflammatory responses. Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory tract infections in infants and elderly, for which no effective treatment or vaccine is currently available. This study investigated the effects of HMGB1 on cytokine secretion, as well as the involvement of NF-κB and TLR4 pathways in RSV-induced HMGB1 release in human airway epithelial cells (AECs) and its proinflammatory effects on several human primary immune cells. Purified HMGB1 was incubated with AECs (A549 and small alveolar epithelial cells) and various immune cells and measured the release of proinflammatory mediators and the activation of NF-κB and P38 MAPK. HMGB1 treatment significantly increased the phosphorylation of NF-κB and P38 MAPK but did not induce the release of cytokines/chemokines from AECs. However, addition of HMGB1 to immune cells did significantly induce the release of cytokines/chemokines and activated the NF-κB and P38 MAPK pathways. We found that activation of NF-κB accounted for RSV-induced HMGB1 secretion in AECs in a TLR4-dependent manner. These results indicated that HMGB1 secreted from AECs can facilitate the secretion of proinflammatory mediators from immune cells in a paracrine mechanism, thus promoting the inflammatory response that contributes to RSV pathogenesis. Therefore, blocking the proinflammatory function of HMGB1 may be an effective approach for developing novel therapeutics.

Integrated Functional Analysis of the Nuclear Proteome of Classically and Alternatively Activated Macrophages.

Macrophages (Mφ) play a central role in coordinating host response to pathogens, cellular injury, and environmental stimuli. Herein, we report multidimensional, nuclear proteomic analyses of protein expression and posttranslational modifications (PTMs) that control biological processes during Mφ activation. For this, Mφ were incubated with IFN-γ/LPS and IL-4, and their differentiation to proinflammatory (M1) and anti-inflammatory (M2a, referred as M2 for simplicity throughtout the manuscript) phenotypes was confirmed by detection of CD64 and CD206 surface markers and TNF-α, arginase I, and iNOS-dependent nitrite levels. We used a sequential method of organellar enrichment and labeling of nuclear fractions with BODIPY FL-maleimide fluorescence dye followed by two-dimensional electrophoresis (2DE) to capture quantitative changes in abundance and S-nitrosylated (SNO) proteome signatures. Exact same gels were then labeled with Pro-Q Diamond to detect protein phosphorylation. MALDI-TOF/TOF MS analysis of the protein spots with fold change of ≥|1.5| in any of the groups yielded 229 identifications. We found that 145, 78, and 173 protein spots in M1 Mφ and 105, 81, and 164 protein spots in M2 Mφ were changed in abundance, S-nitrosylation, and phosphorylation, respectively, with respect to M0 controls (fold change: ≥|1.5|, p ≤ 0.05). Targeted analysis by immunoprecipitation and Western blotting was performed to verify the differential abundance and phosphorylation levels of two of the proteins in M1 and M2 (vs. M0) Mφ. Ingenuity Pathway Analysis of the nuclear proteome datasets showed that the abundance and posttranslational (SNO and Phosphor) modifications of the proteins predicted to be involved in cytoskeletal organization/cell movement, phagocytosis/endocytosis, and cell proliferation/cell death were differentially regulated with proinflammatory and anti-inflammatory activation of Mφ.

A Two-Component DNA-Prime/Protein-Boost Vaccination Strategy for Eliciting Long-Term, Protective T Cell Immunity against Trypanosoma cruzi.

In this study, we evaluated the long-term efficacy of a two-component subunit vaccine against Trypanosoma cruzi infection. C57BL/6 mice were immunized with TcG2/TcG4 vaccine delivered by a DNA-prime/Protein-boost (D/P) approach and challenged with T. cruzi at 120 or 180 days post-vaccination (dpv). We examined whether vaccine-primed T cell immunity was capable of rapid expansion and intercepting the infecting T. cruzi. Our data showed that D/P vaccine elicited CD4+ (30-38%) and CD8+ (22-42%) T cells maintained an effector phenotype up to 180 dpv, and were capable of responding to antigenic stimulus or challenge infection by a rapid expansion (CD8>CD4) with type 1 cytokine (IFNγ+ and TFNα+) production and cytolytic T lymphocyte (CTL) activity. Subsequently, challenge infection at 120 or 180 dpv, resulted in 2-3-fold lower parasite burden in vaccinated mice than was noted in unvaccinated/infected mice. Co-delivery of IL-12- and GMCSF-encoding expression plasmids provided no significant benefits in enhancing the anti-parasite efficacy of the vaccine-induced T cell immunity. Booster immunization (bi) with recombinant TcG2/TcG4 proteins 3-months after primary vaccine enhanced the protective efficacy, evidenced by an enhanced expansion (1.2-2.8-fold increase) of parasite-specific, type 1 CD4+ and CD8+ T cells and a potent CTL response capable of providing significantly improved (3-4.5-fold) control of infecting T. cruzi. Further, CD8+T cells in vaccinated/bi mice were predominantly of central memory phenotype, and capable of responding to challenge infection 4-6-months post bi by a rapid expansion to a poly-functional effector phenotype, and providing a 1.5-2.3-fold reduction in tissue parasite replication. We conclude that the TcG2/TcG4 D/P vaccine provided long-term anti-T. cruzi T cell immunity, and bi would be an effective strategy to maintain or enhance the vaccine-induced protective immunity against T. cruzi infection and Chagas disease.

Macrophages Promote Oxidative Metabolism To Drive Nitric Oxide Generation in Response to Trypanosoma cruzi.

Trypanosoma cruzi is the causative agent of chronic chagasic cardiomyopathy. Why macrophages (mφs), the early responders to infection, fail to achieve parasite clearance is not known. Mouse (RAW 264.7) and human (THP-1 and primary) mφs were infected for 3 h and 18 h with T. cruzi TcI isolates, SylvioX10/4 (SYL, virulent) and TCC (nonpathogenic), which represent mφ stimulation and infection states, respectively. Mφs incubated with lipopolysaccharide and gamma interferon (LPS/IFN-γ) and with interleukin-4 (IL-4) were used as controls. We monitored the cytokine profile (using enzyme-linked immunosorbent assay [ELISA]), reactive oxygen species (ROS; fluorescent probes), nitric oxide (·NO; Griess assay), and metabolic state using a custom-designed mitoxosome array and Seahorse XF24 Analyzer. LPS/IFN-γ treatment of mφs elicited a potent increase in production of tumor necrosis alpha (TNF-α) at 3 h and of ROS and ·NO by 18 h. Upon SYL infection, murine mφs elicited an inflammatory cytokine profile (TNF-α ≫ TGF-ß + IL-10) and low levels of ·NO and ROS production. LPS/IFN-γ treatment resulted in the inhibition of oxidative metabolism at the gene expression and functional levels and a switch to the glycolytic pathway in mφs, while IL-4-treated mφs utilized oxidative metabolism to meet energy demands. SYL infection resulted in an intermediate functional metabolic state with increased mitoxosome gene expression and glycolysis, and IFN-γ addition shut down the oxidative metabolism in SYL-infected mφs. Further, TCC- and SYL-stimulated mφs exhibited similar levels of cell proliferation and production of TNF-α and ROS, while TCC-stimulated mφs exhibited up to 2-fold-higher levels of oxidative metabolism and ·NO production than SYL-infected mφs. Inhibiting ATP-coupled O2 consumption suppressed the ·NO generation in SYL-infected mφs. Mitochondrial oxygen consumption constitutes a mechanism for stimulating ·NO production in mφs during T. cruzi infection. Enhancing the oxidative metabolism provides an opportunity for increased ·NO production and pathogen clearance by mφs to limit disease progression.

TcI Isolates of Trypanosoma cruzi Exploit the Antioxidant Network for Enhanced Intracellular Survival in Macrophages and Virulence in Mice.

Trypanosoma cruzi species is categorized into six discrete typing units (TcI to TcVI) of which TcI is most abundantly noted in the sylvatic transmission cycle and considered the major cause of human disease. In our study, the TcI strains Colombiana (COL), SylvioX10/4 (SYL), and a cultured clone (TCC) exhibited different biological behavior in a murine model, ranging from high parasitemia and symptomatic cardiomyopathy (SYL), mild parasitemia and high tissue tropism (COL), to no pathogenicity (TCC). Proteomic profiling of the insect (epimastigote) and infective (trypomastigote) forms by two-dimensional gel electrophoresis/matrix-assisted laser desorption ionization-time of flight mass spectrometry, followed by functional annotation of the differential proteome data sets (≥2-fold change, P < 0.05), showed that several proteins involved in (i) cytoskeletal assembly and remodeling, essential for flagellar wave frequency and amplitude and forward motility of the parasite, and (ii) the parasite-specific antioxidant network were enhanced in COL and SYL (versus TCC) trypomastigotes. Western blotting confirmed the enhanced protein levels of cytosolic and mitochondrial tryparedoxin peroxidases and their substrate (tryparedoxin) and iron superoxide dismutase in COL and SYL (versus TCC) trypomastigotes. Further, COL and SYL (but not TCC) were resistant to exogenous treatment with stable oxidants (H2O2 and peroxynitrite [ONOO(-)]) and dampened the intracellular superoxide and nitric oxide response in macrophages, and thus these isolates escaped from macrophages. Our findings suggest that protein expression conducive to increase in motility and control of macrophage-derived free radicals provides survival and persistence benefits to TcI isolates of T. cruzi.

Serum-mediated activation of macrophages reflects TcVac2 vaccine efficacy against Chagas disease.

Chagas disease is endemic in Latin America and an emerging infectious disease in the United States. No effective treatments are available. The TcG1, TcG2, and TcG4 antigens are highly conserved in clinically relevant Trypanosoma cruzi isolates and are recognized by B and T cells in infected hosts. Delivery of these antigens as a DNA prime/protein boost vaccine (TcVac2) elicited lytic antibodies and type 1 CD8(+) T cells that expanded upon challenge infection and provided >90% control of parasite burden and myocarditis in chagasic mice. Here we determined if peripheral blood can be utilized to capture the TcVac2-induced protection from Chagas disease. We evaluated the serum levels of T. cruzi kinetoplast DNA (TckDNA), T. cruzi 18S ribosomal DNA (Tc18SrDNA), and murine mitochondrial DNA (mtDNA) as indicators of parasite persistence and tissue damage and monitored the effect of sera on macrophage phenotype. Circulating TckDNA/Tc18SrDNA and mtDNA were decreased by >3- to 5-fold and 2-fold, respectively, in vaccinated infected mice compared to nonvaccinated infected mice. Macrophages incubated with sera from vaccinated infected mice exhibited M2 surface markers (CD16, CD32, CD200, and CD206), moderate proliferation, a low oxidative/nitrosative burst, and a regulatory/anti-inflammatory cytokine response (interleukin-4 [IL-4] plus IL-10 > tumor necrosis factor alpha [TNF-α]). In comparison, macrophages incubated with sera from nonvaccinated infected mice exhibited M1 surface markers, vigorous proliferation, a substantial oxidative/nitrosative burst, and a proinflammatory cytokine response (TNF-α ≫ IL-4 plus IL-10). Cardiac infiltration of macrophages and TNF-α and oxidant levels were significantly reduced in TcVac2-immunized chagasic mice. We conclude that circulating TcDNA and mtDNA levels and macrophage phenotype mediated by serum constituents reflect in vivo levels of parasite persistence, tissue damage, and inflammatory/anti-inflammatory state and have potential utility in evaluating disease severity and efficacy of vaccines and drug therapies.

Mechanisms of Trypanosoma cruzi persistence in Chagas disease.

Trypanosoma cruzi infection leads to development of chronic Chagas disease. In this article, we provide an update on the current knowledge of the mechanisms employed by the parasite to gain entry into the host cells and establish persistent infection despite activation of a potent immune response by the host. Recent studies point to a number of T. cruzi molecules that interact with host cell receptors to promote parasite invasion of the diverse host cells. T. cruzi expresses an antioxidant system and thromboxane A(2) to evade phagosomal oxidative assault and suppress the host's ability to clear parasites. Additional studies suggest that besides cardiac and smooth muscle cells that are the major target of T. cruzi infection, adipocytes and adipose tissue serve as reservoirs from where T. cruzi can recrudesce and cause disease decades later. Further, T. cruzi employs at least four strategies to maintain a symbiotic-like relationship with the host, and ensure consistent supply of nutrients for its own survival and long-term persistence. Ongoing and future research will continue to help refining the models of T. cruzi invasion and persistence in diverse tissues and organs in the host.

Acute muscle mass loss was alleviated with HMGB1 neutralizing antibody treatment in severe burned rats.

Burn injury is associated with muscle wasting, though the involved signaling mechanisms are not well understood. In this study, we aimed to examine the role of high mobility group box 1 (HMGB1) in signaling hyper-inflammation and consequent skeletal muscle impairment after burn. Sprague Dawley rats were randomly assigned into three groups: (1) sham burn, (2) burn, (3) burn/treatment. Animals in group 2 and group 3 received scald burn on 30% of total body surface area (TBSA) and immediately treated with chicken IgY and anti-HMGB1 antibody, respectively. Muscle tissues and other samples were collected at 3-days after burn. Body mass and wet/dry weights of the hind limb muscles (total and individually) were substantially decreased in burn rats. Acute burn provoked the mitochondrial stress and cell death and enhanced the protein ubiquitination and LC3A/B levels that are involved in protein degradation in muscle tissues. Further, an increase in muscle inflammatory infiltrate associated with increased differentiation, maturation and proinflammatory activation of bone marrow myeloid cells and αß CD4+ T and γδ T lymphocytes was noted in in circulation and spleen of burn rats. Treatment with one dose of HMGB1 neutralizing antibody reduced the burn wound size and preserved the wet/dry weights of the hind limb muscles associated with a control in the markers of cell death and autophagy pathways in burn rats. Further, anti-HMGB1 antibody inhibited the myeloid and T cells inflammatory activation and subsequent dysregulated inflammatory infiltrate in the muscle tissues of burn rats. We conclude that neutralization of HMGB1-dependent proteolytic and inflammatory responses has potential beneficial effects in preventing the muscle loss after severe burn injury.

Congenital Transmission of Trypanosoma cruzi in Naturally Infected Dogs.

Background: Congenital transmission (CT) of Trypanosoma cruzi in dogs has not been clearly demonstrated, even though dogs are important reservoirs of this agent. Materials and Methods: Seventeen late pregnant dogs seropositive for T. cruzi were selected, and a total of 84 fetuses were obtained. Blood and heart tissues from the fetuses and dams, and placental tissue from dam were collected. All tissues were analyzed by quantitative polymerase chain reaction (qPCR) for T. cruzi DNA (TcDNA) and inflammatory infiltrate and pathology by histological examination. CT was determined when physical, histological, or molecular evidence of T. cruzi was detected in blood or tissues of the fetuses. Results: A general transmission frequency of 59% was found, and 0.20 ± 0.24 of fetuses per litter were infected. Dams that were qPCR positive for TcDNA in cardiac tissue or blood displayed a transmission frequency of 100% and 67%, respectively. The highest parasite burden was noted in dams that were positive for TcDNA in both blood (82E-01 ± 1.54E-01) and cardiac (5.28E+03 ± 8.85E+03) tissues. In fetuses, higher parasitic burden in blood and cardiac tissue was found in those carried by dams that were seropositive and qPCR positive for TcDNA in cardiac tissue and blood. No amastigote nests were recorded in the cardiac tissue of fetuses in the histopathological studies, but typical lesions of T. cruzi infection were identified in all fetuses where CT occurred. Conclusions: CT of T. cruzi occurred at a high frequency in naturally infected pregnant dogs from the endemic areas.

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.

Animal Models of Trypanosoma cruzi Congenital Transmission.

Chagas disease, initiated by the etiological agent Trypanosoma cruzi, is an endemic infection in the American continent. Although vectorial transmission of T. cruzi is recognized as the main mode of infection, other routes such as congenital and blood transfusion are also documented as important methods of transmission. T. cruzi maternal-fetal transmission has been recorded in humans and examined by some investigators in naturally and experimentally infected mammals. Dogs are recognized as the major reservoir host in maintaining the domestic transmission of T. cruzi; however, the importance of congenital transmission in preserving the infection cycle in dogs has not been studied in detail. In this article, we reviewed the current knowledge of congenital transmission of T. cruzi in humans and compared the placental architecture of humans and different animals with particular attention to rodents, dogs, and non-human primates that have been used as experimental models of T. cruzi infection, congenital transmission, and Chagas disease pathogenesis. The placentas of humans and animals have some similar and dissimilar characteristics that should inform the study design and interpretation of results when evaluating the efficacy of new anti-parasite drugs and therapies against congenital infection.

RBFOX2 is critical for maintaining alternative polyadenylation patterns and mitochondrial health in rat myoblasts.

RBFOX2, which has a well-established role in alternative splicing, is linked to heart diseases. However, it is unclear whether RBFOX2 has other roles in RNA processing that can influence gene expression in muscle cells, contributing to heart disease. Here, we employ both 3'-end and nanopore cDNA sequencing to reveal a previously unrecognized role for RBFOX2 in maintaining alternative polyadenylation (APA) signatures in myoblasts. RBFOX2-mediated APA modulates mRNA levels and/or isoform expression of a collection of genes, including contractile and mitochondrial genes. Depletion of RBFOX2 adversely affects mitochondrial health in myoblasts, correlating with disrupted APA of mitochondrial gene Slc25a4. Mechanistically, RBFOX2 regulation of Slc25a4 APA is mediated through consensus RBFOX2 binding motifs near the distal polyadenylation site, enforcing the use of the proximal polyadenylation site. In sum, our results unveil a role for RBFOX2 in fine-tuning expression of mitochondrial and contractile genes via APA in myoblasts relevant to heart diseases.

Genes of the cGMP-PKG-Ca2+ signaling pathway are alternatively spliced in cardiomyopathy: Role of RBFOX2.

Aberrations in the cGMP-PKG-Ca2+ pathway are implicated in cardiovascular complications of diverse etiologies, though involved molecular mechanisms are not understood. We performed RNA-Seq analysis to profile global changes in gene expression and exon splicing in Chagas disease (ChD) murine myocardium. Ingenuity-Pathway-Analysis of transcriptome dataset identified 26 differentially expressed genes associated with increased mobilization and cellular levels of Ca2+ in ChD hearts. Mixture-of-isoforms and Enrichr KEGG pathway analyses of the RNA-Seq datasets from ChD (this study) and diabetic (previous study) murine hearts identified alternative splicing (AS) in eleven genes (Arhgef10, Atp2b1, Atp2a3, Cacna1c, Itpr1, Mef2a, Mef2d, Pde2a, Plcb1, Plcb4, and Ppp1r12a) of the cGMP-PKG-Ca2+ pathway in diseased hearts. AS of these genes was validated by an exon exclusion-inclusion assay. Further, Arhgef10, Atp2b1, Mef2a, Mef2d, Plcb1, and Ppp1r12a genes consisted RBFOX2 (RNA-binding protein) binding-site clusters, determined by analyzing the RBFOX2 CLIP-Seq dataset. H9c2 rat heart cells transfected with Rbfox2 (vs. scrambled) siRNA confirmed that expression of Rbfox2 is essential for proper exon splicing of genes of the cGMP-PKG-Ca2+ pathway. We conclude that changes in gene expression may influence the Ca2+ mobilization pathway in ChD, and AS impacts the genes involved in cGMP/PKG/Ca2+ signaling pathway in ChD and diabetes. Our findings suggest that ChD patients with diabetes may be at increased risk of cardiomyopathy and heart failure and provide novel ways to restore cGMP-PKG regulated signaling networks via correcting splicing patterns of key factors using oligonucleotide-based therapies for the treatment of cardiovascular complications.

Epidemiology and pathogenesis of maternal-fetal transmission of Trypanosoma cruzi and a case for vaccine development against congenital Chagas disease.

Trypanos o ma cruzi (T. cruzi or Tc) is the causative agent of Chagas disease (CD). It is common for patients to suffer from non-specific symptoms or be clinically asymptomatic with acute and chronic conditions acquired through various routes of transmission. The expecting women and their fetuses are vulnerable to congenital transmission of Tc. Pregnant women face formidable health challenges because the frontline antiparasitic drugs, benznidazole and nifurtimox, are contraindicated during pregnancy. However, it is worthwhile to highlight that newborns can be cured if they are diagnosed and given treatment in a timely manner. In this review, we discuss the pathogenesis of maternal-fetal transmission of Tc and provide a justification for the investment in the development of vaccines against congenital CD.

Potential Role of Antioxidants as Adjunctive Therapy in Chagas Disease.

Chagas disease (CD) is one of the most important neglected tropical diseases in the American continent. Host-derived nitroxidative stress in response to Trypanosoma cruzi infection can induce tissue damage contributing to the progression of Chagas disease. Antioxidant supplementation has been suggested as adjuvant therapy to current treatment. In this article, we synthesize and discuss the current evidence regarding the use of antioxidants as adjunctive compounds to fight harmful reactive oxygen species and lower the tissue oxidative damage during progression of chronic Chagas disease. Several antioxidants evaluated in recent studies have shown potential benefits for the control of oxidative stress in the host's tissues. Melatonin, resveratrol, the combination of vitamin C/vitamin E (vitC/vitE) or curcumin/benznidazole, and mitochondria-targeted antioxidants seem to be beneficial in reducing plasma and cardiac levels of lipid peroxidation products. Nevertheless, further research is needed to validate beneficial effects of antioxidant therapies in Chagas disease.

Metabolic programming of macrophage functions and pathogens control.

Macrophages (Mφ) are central players in mediating proinflammatory and immunomodulatory functions. Unchecked Mφ activities contribute to pathology across many diseases, including those caused by infectious pathogens and metabolic disorders. A fine balance of Mφ responses is crucial, which may be achieved by enforcing appropriate bioenergetics pathways. Metabolism serves as the provider of energy, substrates, and byproducts that support differential Mφ characteristics. The metabolic properties that control the polarization and response of Mφ remain to be fully uncovered for use in managing infectious diseases. Here, we review the various metabolic states in Mφ and how they influence the cell function.

Fluorescence Proteomic Technology to Analyze Peripheral Blood Mononuclear Cells in Chronic Chagas Disease.

The thiol moieties of cysteinyl residues in proteins undergo a number of modifications including nitrosylation, oxidation, persulfidation, sulfenylation, and others. These protein modifications may influence gain as well as loss of function in biological and disease conditions. Herein, we describe a quantitative approach that combines accurate, sensitive fluorescence modification of cysteinyl-S-nitrosyl (SNOFlo) groups that leaves electrophoretic mobility unaffected and offers the measurement of changes in S-nitrosylation (SNO) status relative to protein abundance. This approach has been useful in evaluating the global protein abundance and SNO profile of Chagas seropositive individuals that were categorized in clinically asymptomatic (C/A) and clinically symptomatic (C/S) subgroups and compared to normal healthy (N/H) controls. Through analyzing the proteome datasets with different bioinformatics and statistics tools, potential pathologic mechanisms in disease progression are identified. We also propose a panel of protein biomarkers that have a potential to identify the infected individuals at risk of developing clinical Chagas disease.

Redox Balance Keepers and Possible Cell Functions Managed by Redox Homeostasis in Trypanosoma cruzi.

The toxicity of oxygen and nitrogen reactive species appears to be merely the tip of the iceberg in the world of redox homeostasis. Now, oxidative stress can be seen as a two-sided process; at high concentrations, it causes damage to biomolecules, and thus, trypanosomes have evolved a strong antioxidant defense system to cope with these stressors. At low concentrations, oxidants are essential for cell signaling, and in fact, the oxidants/antioxidants balance may be able to trigger different cell fates. In this comprehensive review, we discuss the current knowledge of the oxidant environment experienced by T. cruzi along the different phases of its life cycle, and the molecular tools exploited by this pathogen to deal with oxidative stress, for better or worse. Further, we discuss the possible redox-regulated processes that could be governed by this oxidative context. Most of the current research has addressed the importance of the trypanosomes' antioxidant network based on its detox activity of harmful species; however, new efforts are necessary to highlight other functions of this network and the mechanisms underlying the fine regulation of the defense machinery, as this represents a master key to hinder crucial pathogen functions. Understanding the relevance of this balance keeper program in parasite biology will give us new perspectives to delineate improved treatment strategies.