HIV-1 infection in astrocytes raises intracellular ROS improving Trypanosoma cruzi multiplication

OJEDA DIEGO; CEVALLOS CINTIA; QUARLERI JORGE; URQUIZA JAVIER; TURK GABRIELA

Mexico

Conferencia; 10th IAS Conference on HIV Science (IAS 2019); 2019

IAS

Background: Trypanosoma cruzi (Tc) is an intracellular parasite that causes Chagas disease and may compromise seriously the central nervous system (CNS), mainly in immunosuppressed individuals as occurs in the HIV coinfection. Astrocytes play a crucial role in maintaining the environment of healthy neurons; however, they can harbor both, HIV and Tc. HIV infection triggers pronounced reactive oxidative stress (ROS) that if increased to levels which cannot be neutralized by the defense mechanisms, they damage biological molecules, alter their functions, and also act as signaling molecules thus generating a spectrum of pathologies. Paradoxically and supported in recent evidence, it suggests that parasite growth is stimulated in oxidative environments. This type of interaction could worst manifestations of Chagas disease observed in immunocompetent patients.Methods: Cultured normal human astrocytes (NHA, Lonza) were infected with Tc (K98 clone modified to express GFP) and HIV (NL4.3). Tc infection and multiplication were evaluated by flow cytometry analysis at 3 days-post-exposition (dpe) and real time PCR to quantify parasite DNA. Cell death was measured by Annexin V/7-AAD, and propidium iodide detection by FACS. Oxidative stress on astrocytes was induced adding tert-Butylhydroperoxide (tBH; 50 µM), while ROS was quantified by FACS using MitoSOX; MitoTEMPO and ascorbic acid (AA) were used as ROS-scavengers.Results: Trypanosoma cruzi infection was significantly higher in astrocytes previously infected by HIV (Tc 8.2%±0.09 vs. HIV/Tc 20.45%±1.20), as well as its multiplication (Tc 505.5± 7.8 vs. HIV/Tc 706.5±12 measured as median fluorescence intensity). When ROS scavengers were added, a detrimental effect was observed on Tc infectivity (HIV/Tc + MitoSOX or AA 10.08%±0.67 vs. HIV/Tc 40.75%±2.90). In contrast, Tc infection of astrocytes was significantly improved under pro-oxidant condition with tBH (Tc 3.9%±0.27 vs. Tc+tBH 19.35%±0.07). In line, the level of Tc DNA was 5-fold higher when HIV coexists than on its absence. Conclusions: Increased level of intracellular ROS prompted by HIV on astrocytes enhances both Trypanosoma cruzi infection and multiplication. Such exploitation by the parasite may improve cell viability. This interaction between HIV and Trypanosoma cruzi could propitiate a worsened course of the Chagas disease in the CNS.