DNA double-strand breaks in the Toxoplasma gondii-infected cells by the action of reactive oxygen species

Abstract

Background Toxoplasma gondii is an obligate parasite of all warm-blooded animals around the globe. Once infecting a cell, it manipulates the host’s DNA damage response that is yet to be elucidated. The objectives of the present study were three-fold: (i) to assess DNA damages in T. gondii-infected cells in vitro; (ii) to ascertain causes of DNA damage in T. gondii-infected cells; and (iii) to investigate activation of DNA damage responses during T. gondii infection. Methods HeLa, Vero and HEK293 cells were infected with T. gondii at a multiplicity of infection (MOI) of 10:1. Infected cells were analyzed for a biomarker of DNA double-strand breaks (DSBs) γH2AX at 10 h, 20 h or 30 h post-infection using both western blot and immunofluorescence assay. Reactive oxygen species (ROS) levels were measured using 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA), and ROS-induced DNA damage was inhibited by a ROS inhibitor N-acetylcysteine (NAC). Lastly, DNA damage responses were evaluated by detecting the active form of ataxia telangiectasia mutated/checkpoint kinase 2 (ATM/CHK2) by western blot. Results γH2AX levels in the infected HeLa cells were significantly increased over time during T. gondii infection compared to uninfected cells. NAC treatment greatly reduced ROS and concomitantly diminished γH2AX in host cells. The phosphorylated ATM/CHK2 were elevated in T. gondii-infected cells. Conclusions Toxoplasma gondii infection triggered DNA DSBs with ROS as a major player in host cells in vitro. It also activated DNA damage response pathway ATM/CHK2. Toxoplasma gondii manages to keep a balance between survival and apoptosis of its host cells for the benefit of its own survival.

The Immune Response in Adipocytes and Their Susceptibility to Infection: A Possible Relationship with Infectobesity

“…The dysregulation of adipocytes then leads to metabolic syndrome due to an increase in the number of adipocytes and in insulin receptor sensitivity [ 154 , 155 , 156 ]. Additionally, adipocytes produce reactive oxygen species in response to inflammation and infections, including T. gondii infection [ 157 , 158 , 159 , 160 ] ( Figure 2 F). In general, the crosstalk between host immunity and parasites determines the dissemination of parasites and disease severity.…”

Modulation of autophagy as a therapeutic strategy for Toxoplasma gondii infection

“…Oxidative stress in the host cells is toxic to parasites, at the same time, it has deleterious consequences on the host ( Zhuang et al., 2020 ). The immune response evoked by parasite infection induces the production of reactive oxygen species (ROS) which suppresses the activity of T. gondii in monocytes of infected animals.…”

Disruption of Toxoplasma gondii-Induced Host Cell DNA Replication Is Dependent on Contact Inhibition and Host Cell Type

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