Reactive oxygen species and nitric oxide imbalances lead to in vivo and in vitro arrhythmogenic phenotype in acute phase of experimental Chagas disease

Author(s)

Santos-Miranda, Artur ^{[1, 2]} ; Joviano-Santos, Julliane Vasconcelos ^[1] ; Ribeiro, Grazielle Alves ^[2] ; Botelho, Ana Flavia M. ^[3] ; Rocha, Peter ^[2] ; Vieira, Leda Quercia ^[2] ; Cruz, Jader Santos ^[2] ; Roman-Campos, Danilo ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Dept Biophys, Sao Paulo - Brazil

^[2] Univ Fed Minas Gerais, Inst Ciencias Biol, Dept Biochem & Immunol, Belo Horizonte, MG - Brazil

^[3] Univ Fed Goias, Dept Vet Med, Escola Vet & Zootecnia, Goiania, Go - Brazil

• Document type: Journal article
• Source: PLOS PATHOGENS; v. 16, n. 3 MAR 2020.
• Web of Science Citations: 6

Abstract

Chagas Disease (CD) is one of the leading causes of heart failure and sudden death in Latin America. Treatments with antioxidants have provided promising alternatives to ameliorate CD. However, the specific roles of major reactive oxygen species (ROS) sources, including NADPH-oxidase 2 (NOX2), mitochondrial-derived ROS and nitric oxide (NO) in the progression or resolution of CD are yet to be elucidated. We used C57BL/6 (WT) and a gp91(PHOX) knockout mice (PHOX-/-), lacking functional NOX2, to investigate the effects of ablation of NOX2-derived ROS production on the outcome of acute chagasic cardiomyopathy. Infected PHOX-/- cardiomyocytes displayed an overall pro-arrhythmic phenotype, notably with higher arrhythmia incidence on ECG that was followed by higher number of early afterdepolarizations (EAD) and 2.5-fold increase in action potential (AP) duration alternans, compared to AP from infected WT mice. Furthermore, infected PHOX-/- cardiomyocytes display increased diastolic {[}Ca2+], aberrant Ca2+ transient and reduced Ca2+ transient amplitude. Cardiomyocyte contraction is reduced in infected WT and PHOX-/- mice, to a similar extent. Nevertheless, only infected PHOX-/- isolated cardiomyocytes displayed significant increase in non-triggered extra contractions (appearing in 75% of cells). Electro-mechanical remodeling of infected PHOX(-/-)cardiomyocytes is associated with increase in NO and mitochondria-derived ROS production. Notably, EADs, AP duration alternans and in vivo arrhythmias were reverted by pre-incubation with nitric oxide synthase inhibitor L-NAME. Overall our data show for the first time that lack of NOX2-derived ROS promoted a pro-arrhythmic phenotype in the heart, in which the crosstalk between ROS and NO could play an important role in regulating cardiomyocyte electro-mechanical function during acute CD. Future studies designed to evaluate the potential role of NOX2-derived ROS in the chronic phase of CD could open new and more specific therapeutic strategies to treat CD and prevent deaths due to heart complications. Author summary Chagas disease (CD) is an important neglected disease mainly found in developing countries. However, due to migration flow, it became a health problem worldwide. Infection by Trypanosoma cruzi typically occurs after an infected Triatominae vector takes a blood meal and leaves parasites in its feces nearby the bite wound. Two distinct symptomatic stages of CD are typical, an acute phase that lasts few weeks and a chronic stage, that can last for 10-30 years after infection, and may lead to severe cardiac arrhythmias and death. Here, we used an experimental model of acute CD to study the involvement of reactive oxygen species (ROS) and nitric oxide (NO) with structural and functional remodeling of cardiomyocytes and the heart. We found that an unbalanced production of two sources of reactive species may worsen cellular electromechanical dysfunction, leading to more severe arrhythmias despite additional structural changes in heart tissue. Interestingly, it was possible to attenuate the unbalanced relationship between ROS and NO by inhibition of NO production, leading to recovery of electrical function of heart cells and ameliorating in vivo heart arrhythmia. Thus, in the long term, our study may contribute to the development of new therapies to individuals with the cardiac form of CD. (AU)

• FAPESP's process: 18/20777-3 - Genetic variants of the Nav 1.5 sodium channel and its therapeutic implications.
• Grantee: Julliane Vasconcelos Joviano dos Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 14/09861-1 - The role of late sodium current in the inherited and acquired cardiac arrhythmias: from the biophysics properties to new therapeutic targets
• Grantee: Danilo Roman Campos
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 18/22830-9 - Involvement of the Ca2+/ Calmodulin/CAMKII signaling axis in the electrical and contractile dysfunctions of the heart in the chronic phase of Chagas Disease
• Grantee: Artur Santos Miranda
• Support Opportunities: Scholarships in Brazil - Post-Doctoral