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Chagas Disease Megaesophagus Patients Carrying Variant MRPS18B P260A Display Nitro-Oxidative Stress and Mitochondrial Dysfunction in Response to IFN-γ Stimulus.

ABSTRACT: Chagas disease (CD), caused by the protozoan parasite Trypanosoma cruzi, affects 8 million people, and around 1/3 develop chronic cardiac (CCC) or digestive disease (megaesophagus/megacolon), while the majority remain asymptomatic, in the indeterminate form of Chagas disease (ASY). Most CCC cases in families with multiple Chagas disease patients carry damaging mutations in mitochondrial genes. We searched for exonic mutations associated to chagasic megaesophagus (CME) in genes essential to mitochondrial processes. We performed whole exome sequencing of 13 CME and 45 ASY patients. We found the damaging variant MRPS18B 688C > G P230A, in five out of the 13 CME patients (one of them being homozygous; 38.4%), while the variant appeared in one out of 45 ASY patients (2.2%). We analyzed the interferon (IFN)-γ-induced nitro-oxidative stress and mitochondrial function of EBV-transformed lymphoblastoid cell lines. We found the CME carriers of the mutation displayed increased levels of nitrite and nitrated proteins; in addition, the homozygous (G/G) CME patient also showed increased mitochondrial superoxide and reduced levels of ATP production. The results suggest that pathogenic mitochondrial mutations may contribute to cytokine-induced nitro-oxidative stress and mitochondrial dysfunction. We hypothesize that, in mutation carriers, IFN-γ produced in the esophageal myenteric plexus might cause nitro-oxidative stress and mitochondrial dysfunction in neurons, contributing to megaesophagus.

SUBMITTER: Silva KDA

PROVIDER: S-EPMC9496350 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature

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Chagas Disease Megaesophagus Patients Carrying Variant <i>MRPS18B</i> P260A Display Nitro-Oxidative Stress and Mitochondrial Dysfunction in Response to IFN-γ Stimulus.

Silva Karla Deysiree Alcântara KDA Nunes João Paulo Silva JPS Andrieux Pauline P Brochet Pauline P Almeida Rafael Ribeiro RR Kuramoto Takara Andréia Cristina Kazue ACK Pereira Natalia Bueno NB Abel Laurent L Cobat Aurelie A Zaniratto Ricardo Costa Fernandes RCF Levy Débora D Bydlowski Sergio Paulo SP Cecconello Ivan I Seguro Francisco Carlos Bernal da Costa FCBDC Kalil Jorge J Chevillard Christophe C Cunha-Neto Edecio E

Biomedicines 20220907 9

Chagas disease (CD), caused by the protozoan parasite Trypanosoma cruzi, affects 8 million people, and around 1/3 develop chronic cardiac (CCC) or digestive disease (megaesophagus/megacolon), while the majority remain asymptomatic, in the indeterminate form of Chagas disease (ASY). Most CCC cases in families with multiple Chagas disease patients carry damaging mutations in mitochondrial genes. We searched for exonic mutations associated to chagasic megaesophagus (CME) in genes essential to mitoc ...[more]

PMID: 36140315

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Project description:Infection by the protozoan Trypanosoma cruzi causes Chagas disease cardiomyopathy (CCC) and can lead to arrhythmia, heart failure and death. Chagas disease affects 8 million people worldwide, and chronic production of the cytokines IFN-γ and TNF-α by T cells together with mitochondrial dysfunction are important players for the poor prognosis of the disease. Mitochondria occupy 40% of the cardiomyocytes volume and produce 95% of cellular ATP that sustain the life-long cycles of heart contraction. As IFN-γ and TNF-α have been described to affect mitochondrial function, we hypothesized that IFN-γ and TNF-α are involved in the myocardial mitochondrial dysfunction observed in CCC patients. In this study, we quantified markers of mitochondrial dysfunction and nitro-oxidative stress in CCC heart tissue and in IFN-γ/TNF-α-stimulated AC-16 human cardiomyocytes. We found that CCC myocardium displayed increased levels of nitro-oxidative stress and reduced mitochondrial DNA as compared with myocardial tissue from patients with dilated cardiomyopathy (DCM). IFN-γ/TNF-α treatment of AC-16 cardiomyocytes induced increased nitro-oxidative stress and decreased the mitochondrial membrane potential (ΔΨm). We found that the STAT1/NF-κB/NOS2 axis is involved in the IFN-γ/TNF-α-induced decrease of ΔΨm in AC-16 cardiomyocytes. Furthermore, treatment with mitochondria-sparing agonists of AMPK, NRF2 and SIRT1 rescues ΔΨm in IFN-γ/TNF-α-stimulated cells. Proteomic and gene expression analyses revealed that IFN-γ/TNF-α-treated cells corroborate mitochondrial dysfunction, transmembrane potential of mitochondria, altered fatty acid metabolism and cardiac necrosis/cell death. Functional assays conducted on Seahorse respirometer showed that cytokine-stimulated cells display decreased glycolytic and mitochondrial ATP production, dependency of fatty acid oxidation as well as increased proton leak and non-mitochondrial oxygen consumption. Together, our results suggest that IFN-γ and TNF-α cause direct damage to cardiomyocytes' mitochondria by promoting oxidative and nitrosative stress and impairing energy production pathways. We hypothesize that treatment with agonists of AMPK, NRF2 and SIRT1 might be an approach to ameliorate the progression of Chagas disease cardiomyopathy.

Project description:BackgroundChagas disease is a neglected tropical disease. About 6 to 8 million people are chronically infected and 10% to 15% develop irreversible gastrointestinal disorders, including megaesophagus. Treatment focuses on improving symptoms, and isosorbide and nifedipine may be used for this purpose.MethodologyWe conducted a systematic review to evaluate the effectiveness of pharmacological treatment for Chagas' megaesophagus. We searched MEDLINE, Embase and LILACS databases up to January 2018. We included both observational studies and RCTs evaluating the effects of isosorbide or nifedipine in adult patients with Chagas' megaesophagus. Two reviewers screened titles and abstracts, selected eligible studies and extracted data. We assessed the risk of bias using NIH 'Quality Assessment Tool for Before-After (Pre-Post) Studies with No Control Group' and RoB 2.0 tool. Overall quality of evidence was assessed using GRADE.Principal findingsWe included eight studies (four crossover RCTs, four before-after studies). Three studies evaluated the effect of isosorbide on lower esophageal sphincter pressure (LESP), showing a significant reduction (mean difference -10.52mmHg, 95%CI -13.57 to-7.47, very low quality of evidence). Three studies reported the effect of isosorbide on esophageal emptying, showing a decrease in esophageal retention rates (mean difference -22.16%, 95%CI -29.94 to -14.38, low quality of evidence). In one study, patients on isosorbide reported improvement in the frequency and severity of dysphagia (moderate quality of evidence). Studies evaluating nifedipine observed a decrease in LESP but no effect on esophageal emptying (very low and low quality of evidence, respectively). Isosorbide had a higher incidence of headache as a side effect than nifedipine.ConclusionsAlthough limited, available evidence shows that both isosorbide and nifedipine are effective in reducing esophageal symptoms. Isosorbide appears to be more effective, and its use is supported by a larger number of studies; nifedipine, however, appears to have a better tolerability profile.Trial registrationPROSPERO CRD42017055143. ClinicalTrials.gov CRD42017055143.

Project description:Microglia (tissue-resident macrophages) represent the main cell type of the innate immune system in the CNS; however, the mechanisms that control the activation of microglia are widely unknown. We systematically explored microglial activation and functional microglia-neuron interactions in organotypic hippocampal slice cultures, i.e., postnatal cortical tissue that lacks adaptive immunity. We applied electrophysiological recordings of local field potential and extracellular K(+) concentration, immunohistochemistry, design-based stereology, morphometry, Sholl analysis, and biochemical analyses. We show that chronic activation with either bacterial lipopolysaccharide through Toll-like receptor 4 (TLR4) or leukocyte cytokine IFN-γ induces reactive phenotypes in microglia associated with morphological changes, population expansion, CD11b and CD68 up-regulation, and proinflammatory cytokine (IL-1β, TNF-α, IL-6) and nitric oxide (NO) release. Notably, these reactive phenotypes only moderately alter intrinsic neuronal excitability and gamma oscillations (30-100 Hz), which emerge from precise synaptic communication of glutamatergic pyramidal cells and fast-spiking, parvalbumin-positive GABAergic interneurons, in local hippocampal networks. Short-term synaptic plasticity and extracellular potassium homeostasis during neural excitation, also reflecting astrocyte function, are unaffected. In contrast, the coactivation of TLR4 and IFN-γ receptors results in neuronal dysfunction and death, caused mainly by enhanced microglial inducible nitric oxide synthase (iNOS) expression and NO release, because iNOS inhibition is neuroprotective. Thus, activation of TLR4 in microglia in situ requires concomitant IFN-γ receptor signaling from peripheral immune cells, such as T helper type 1 and natural killer cells, to unleash neurotoxicity and inflammation-induced neurodegeneration. Our findings provide crucial mechanistic insight into the complex process of microglia activation, with relevance to several neurologic and psychiatric disorders.

Dataset Information

Chagas Disease Megaesophagus Patients Carrying Variant MRPS18B P260A Display Nitro-Oxidative Stress and Mitochondrial Dysfunction in Response to IFN-γ Stimulus.

Publications

Chagas Disease Megaesophagus Patients Carrying Variant <i>MRPS18B</i> P260A Display Nitro-Oxidative Stress and Mitochondrial Dysfunction in Response to IFN-γ Stimulus.

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