Latent toxoplasmosis, Cytomegalovirus, and Herpes Simplex Virus infections and risk of motorcycle accidents: A case-control study in a county with a high rate of motorcycle injuries in Iran.

BACKGROUND: Road traffic injuries (RTIs) are among the most important issues worldwide. Several studies reported that infection with the neurotropic parasite Toxoplasma gondii (T. gondii) increased the risk of car accidents. In this study, our objective was to investigate the possible associations among latent T. gondii, Cytomegalovirus (CMV), and Herpes Simplex Virus (HSV) infections with the risk of motorcycle accidents in Jahrom (Fars Province), which is a county with a high rate of motorcycle accidents in Iran. METHODS: In the setting of a case-control study; 176 motorcyclist men, including 88 survivors of motorcycle accidents and 88 motorcyclist without accidents, were considered as case and control groups, respectively. Rates of latent infections with T. gondii, CMV, and HSV were assessed by an enzyme-linked immunosorbent assay (ELISA). RESULTS: Eleven of 88 (12.5%) in the case group and 22 of 88 (25.0%) in controls were positive for anti-T. gondii IgG antibodies, this difference was statistically significant (OR = 0.42; CI: 0.19-0.95, p = 0.03). The general seroprevalence of CMV (94.3% in the case group vs. 87.5% in the control group, OR = 2.37; CI: 0.78-7.13, p = 0.12) and HSV (63.6% in the case group vs. 62.5% in the control group, OR = 1.05; CI: 0.57-1.94, p = 0.87) were not significantly different between the case and control groups. CONCLUSIONS: Although latent toxoplasmosis has been associated with traffic accidents in recent reports, we found a negative association between latent toxoplasmosis and motorcycle accidents among survivors of these accidents. As such, latent CMV and HSV infections did not differ significantly between the cases compared to the control groups.

Exploring the interplay of chronic toxoplasmosis and NMDAR dysfunction: Insights into schizophrenia-like behaviors and therapeutic potential.

Background: Chronic toxoplasmosis has been strongly implicated in the development of psychosis and schizophrenia. Additionally, the understanding of schizophrenia has been significantly reshaped by insights into N-methyl-D-aspartate receptor (NMDAR) hypofunction. Aim: This study aimed to compare the behavioral, antioxidant, and NMDAR changes in mice subjected to Toxoplasma gondii infection and those treated with ketamine to induce schizophrenia-like symptoms. Methods: Sixty male BALB/c mice were divided into six groups: toxoplasmosis (TOXO) (infected), ketamine-induced schizophrenia (KET), TOXO+KET, TOXO+sulfadiazine-trimethoprim treatment (SDT), TOXO+KET+SDT, and control (CON) (uninfected). After 10 weeks post-infection, behavioral tests were conducted, brain antioxidant status and lipid peroxidation were analyzed, and NMDA-NR1/NR2A expressions were assessed. TOXO and KET induced distinct behaviors: hyperlocomotion, anxiety, and memory impairment. Results: Antioxidant enzyme levels decreased, and lipid peroxidation increased in TOXO and schizophrenic mice brains. NMDAR downregulation, especially NR-1 and NR2A, was evident due to T. gondii and ketamine. Sulfadiazine-trimethoprim ameliorated NMDAR downregulation, but not all of the behavioral alterations. Conclusion: Further studies are needed to elucidate specific NMDAR subunit roles in toxoplasmosis-induced pathophysiology, offering potential therapeutic insights. This investigation highlights the intricate relationship between chronic toxoplasmosis, NMDAR dysfunction, and schizophrenia-like behaviors. Insights gained could pave the way for innovative interventions targeting both cognitive and neurological impairments associated with these conditions.

Toxoplasma gondii and Toxocara spp. contamination in university area.

Toxoplasma gondii and Toxocara spp. zoonotic infections may cause severe systemic and ocular illness in infected individuals. Cats play a significant role in environmental contamination and the transmission of parasites. The goal of the present study was to investigate the prevalence of Toxoplasma gondii (T. gondii) and Toxocara spp. infection among stray cats at Ahvaz Jundishapur University of Medical Sciences campus. The current descriptive study began with the collection of 170 fresh cat faecal samples from various sites in the Ahvaz Jundishapur University of Medical Sciences area. Sheather's sugar flotation method was applied to all specimens, and parasites were identified and examined microscopically. Next, a nested-PCR assay, sequencing, and real-time PCR with high-resolution melting curve (HRM) analysis were performed. In this study, out of 170 cat faecal samples microscopically evaluated, 8 (4.70%) and 37 (21.76%) were infected with T. gondii oocysts and Toxocara eggs, respectively. Using nested PCR, 8 out of 170 samples (4.70%) were found to be infected with T. gondii. HRM analysis showed that all isolates could be classified into three genetic lineages. Considerable prevalence, exceeding 50% for Toxocara and surpassing 25% for Toxoplasma in certain instances, along with genetic diversity, was observed in the present study. Hence, it is suggested that all individuals, including kindergarten children, students, employees, workers, and pregnant women who are in contact with their surroundings, take the necessary precautions.

Sero-prevalence of Toxoplasma gondii before and during the COVID-19 pandemic in Northwestern Iran.

BACKGROUND: Toxoplasma gondii (T. gondii) is a ubiquitous protozoan parasite on our planet that causes toxoplasmosis. This study evaluated the seroprevalence and related risk factors for T. gondii infection in a population referred to healthcare centers in Meshkin-Shahr, Northwest Iran. METHODS: A total of 400 blood samples were randomly collected from the general population and assessed using the anti-Toxoplasma antibodies, Immunoglobulin G and M (IgG and IgM) Enzyme-linked immunosorbent assay (ELISA) Kits in two steps before and during the coronavirus disease 2019 (COVID-19) pandemic, 2019-2020. The results were analyzed through logistic regression via SPSS 26 software. RESULTS: Before the COVID-19 pandemic, anti-toxoplasma antibodies were detected in 39% of individuals (IgG: 38%, IgM: 0.5%, and IgG-IgM: 0.5%). Among the eleven risk factors evaluated, contact with soil and people awareness were significantly associated with T. gondii infection (p < 0.05). However, factors such as females, 20-39 age groups, junior high schools, housewives, rural areas, raw meat or vegetable consumption, vegetable or fruits washed by water, not detergent, and cat owners did not show a significant relationship with seropositivity (p > 0.05). After the outbreak of the COVID-19 pandemic, the overall seroprevalence for anti-T. gondii antibody increased to 49.7% (IgG: 47.7%, IgM: 0.5%, and IgG and IgM: 1.5%). Among these patients, 26% were positive for COVID-19. Additionally, before the COVID-19 pandemic, 40 samples were negative for anti-T. gondii antibodies but later became positive. The crude and adjusted models suggested that toxoplasmosis may be a possible risk factor for increased susceptibility to COVID-19, with an odds ratio (OR) of 1.28 (95% confidence interval (CI), 0.82-1.99; P < 0.05). Conversely, a non-significant protective effect against latent toxoplasmosis was observed in COVID-19-positive individuals (OR = 0.99; 95% CI, 0.51-1.92; P > 0.05), and COVID-19 positivity did not increase the levels of anti-T. gondii IgG antibodies. CONCLUSIONS: The general population in this region had a moderate seroprevalence of T. gondii. The increased number of COVID-19-positive patients with latent toxoplasmosis highlights the need to pay attention to the early diagnosis and proper treatment of toxoplasmosis in these patients and implement preventive programs in these areas for future possible viral infections.

Toxoplasma infection induces an aged neutrophil population in the CNS that is associated with neuronal protection.

BACKGROUND: Infection with the protozoan parasite Toxoplasma gondii leads to the formation of lifelong cysts in neurons that can have devastating consequences in the immunocompromised. In the immunocompetent individual, anti-parasitic effector mechanisms and a balanced immune response characterized by pro- and anti-inflammatory cytokine production establishes an asymptomatic infection that rarely leads to neurological symptoms. Several mechanisms are known to play a role in this successful immune response in the brain including T cell production of IFNγ and IL-10 and the involvement of CNS resident cells. This limitation of clinical neuropathology during chronic infection suggests a balance between immune response and neuroprotective mechanisms that collectively prevent clinical manifestations of disease. However, how these two vital mechanisms of protection interact during chronic Toxoplasma infection remains poorly understood. MAIN TEXT: This study demonstrates a previously undescribed connection between innate neutrophils found chronically in the brain, termed "chronic brain neutrophils" (CBNeuts), and neuroprotective mechanisms during Toxoplasma infection. Lack of CBNeuts during chronic infection, accomplished via systemic neutrophil depletion, led to enhanced infection and deleterious effects on neuronal regeneration and repair mechanisms in the brain. Phenotypic and transcriptomic analysis of CBNeuts identified them as distinct from peripheral neutrophils and revealed two main subsets of CBNeuts that display heterogeneity towards both classical effector and neuroprotective functions in an age-dependent manner. Further phenotypic profiling defined expression of the neuroprotective molecules NRG-1 andErbB4 by these cells, and the importance of this signaling pathway during chronic infection was demonstrated via NRG-1 treatment studies. CONCLUSIONS: In conclusion, this work identifies CBNeuts as a heterogenous population geared towards both classical immune responses and neuroprotection during chronic Toxoplasma infection and provides the foundation for future mechanistic studies of these cells.

[Preliminary observation on the development and dynamic changes of chronic toxoplasmosis in mice].

OBJECTIVE: To investigate the development and dynamic changes of cysts in the brain of mice following infection with different forms of Toxoplasma gondii, so as to provide insights into for toxoplasmosis prevention and control. METHODS: ICR mice at ages of 6 to 8 weeks, each weighing 20 to 25 g, were intraperitoneally injected with tachyzoites of the T. gondii PRU strain at a dose of 1 × 105 tachyzoites per mouse, orally administered with cysts at a dose of 20 oocysts per mouse or oocysts at a dose of 200 oocysts per mouse for modeling chronic T. gondii infection in mice, and the clinical symptoms and survival of mice were observed post-infection. Mice were orally infected with T. gondii cysts at doses of 10 (low-dose group), 20 (medium-dose group), 40 cysts per mouse (high-dose group), and the effect of different doses of T. gondii infections on the number of cysts was examined in the mouse brain. Mice were orally administered with T. gondii cysts at a dose of 20 cysts per mouse, and grouped according to gender (female and male) and time points of infections (20, 30, 60, 90, 120, 150, 180 days post-infection), and the effects of gender and time points of infections on the number of cysts was examined in the mouse brain. In addition, mice were divided into the tachyzoite group (Group T), the first-generation cyst group (Group C1), the second-generation cyst group (Group C2), the third-generation cyst (Group C3) and the fourth-generation cyst group (Group C4). Mice in the Group T were intraperitoneally injected with T. gondii tachyzoites at a dose of 1 × 105 tachyzoites per mouse, and the cysts were collected from the mouse brain tissues 30 days post-infection, while mice in the Group C1 were orally infected with the collected cysts at a dose of 30 cysts per mouse. Continuous passage was performed by oral administration with cysts produced by the previous generation in mice, and the effect of continuous passage on the number of cysts was examined in the mouse brain. RESULTS: Following infection with T. gondii tachyzoites, cysts and oocysts in mice, obvious clinical symptoms were observed on days 6 to 13 and mice frequently died on days 7 to 12. The survival rates of mice were 67.0%, 87.0% and 53.0%, and the mean numbers of cysts were (516.0 ± 257.2), (1 203.0 ± 502.0) and (581.0 ± 183.1) in the mouse brain (F = 11.94, P < 0.01) on day 30 post-infection with T. gondii tachyzoites, cysts and oocysts, respectively, and the numbers of cysts in the brain tissues were significantly lower in mice infected with T. gondii tachyzoites and oocysts than in those infected with cysts (all P values < 0.01). The survival rates of mice were 87.0%, 87.0% and 60.0%, and the mean numbers of cysts were (953.0 ± 355.5), (1 084.0 ± 474.3) and (1 113.0 ± 546.0) in the mouse brain in the low-, medium- and high-dose groups on day 30 post-infection, respectively (F = 0.42, P > 0.05). The survival rates of male and female mice were 73.0% and 80.0%, and the mean numbers of cysts were (946.4 ± 411.4) and (932.1 ± 322.4) in the brain tissues of male and female mice, respectively (F = 1.63, P > 0.05). Following continuous passage, the mean numbers of cysts were (516.0 ± 257.2), (1 203.0 ± 502.0), (896.8 ± 332.3), (782.5 ± 423.9) and (829.2 ± 306.0) in the brain tissues of mice in the T, C1, C2, C3 and C4 groups, respectively (F = 4.82, P < 0.01), and the number of cysts was higher in the mouse brain in Group 1 than in Group T (P < 0.01). Following oral administration of 20 T. gondii cysts in mice, cysts were found in the moues brain for the first time on day 20 post-infection, and the number of cysts gradually increased over time, peaked on days 30 and 90 post-infection and then gradually decreased; however, the cysts were still found in the mouse brain on day 180 post-infection. CONCLUSIONS: There is a higher possibility of developing chronic T. gondii infection in mice following infection with cysts than with oocysts or tachyzoites and the most severe chronic infection is seen following infection with cysts. The number of cysts does not correlate with the severity of chronic T. gondii infection, and the number of cysts peaks in the mouse brain on days 30 and 90 post-infection.

Intestinal microbiota imbalance resulted by anti-Toxoplasma gondii immune responses aggravate gut and brain injury.

BACKGROUND: Toxoplasma gondii infection affects a significant portion of the global population, leading to severe toxoplasmosis and, in immunocompromised patients, even death. During T. gondii infection, disruption of gut microbiota further exacerbates the damage to intestinal and brain barriers. Therefore, identifying imbalanced probiotics during infection and restoring their equilibrium can regulate the balance of gut microbiota metabolites, thereby alleviating tissue damage. METHODS: Vimentin gene knockout (vim-/-) mice were employed as an immunocompromised model to evaluate the influence of host immune responses on gut microbiota balance during T. gondii infection. Behavioral experiments were performed to assess changes in cognitive levels and depressive tendencies between chronically infected vim-/- and wild-type (WT) mice. Fecal samples were subjected to 16S ribosomal RNA (rRNA) sequencing, and serum metabolites were analyzed to identify potential gut probiotics and their metabolites for the treatment of T. gondii infection. RESULTS: Compared to the immunocompetent WT sv129 mice, the immunocompromised mice exhibited lower levels of neuronal apoptosis and fewer neurobehavioral abnormalities during chronic infection. 16S rRNA sequencing revealed a significant decrease in the abundance of probiotics, including several species of Lactobacillus, in WT mice. Restoring this balance through the administration of Lactobacillus murinus and Lactobacillus gasseri significantly suppressed the T. gondii burden in the intestine, liver, and brain. Moreover, transplantation of these two Lactobacillus spp. significantly improved intestinal barrier damage and alleviated inflammation and neuronal apoptosis in the central nervous system. Metabolite detection studies revealed that the levels of various Lactobacillus-related metabolites, including indole-3-lactic acid (ILA) in serum, decreased significantly after T. gondii infection. We confirmed that L. gasseri secreted much more ILA than L. murinus. Notably, ILA can activate the aromatic hydrocarbon receptor signaling pathway in intestinal epithelial cells, promoting the activation of CD8+ T cells and the secretion of interferon-gamma. CONCLUSION: Our study revealed that host immune responses against T. gondii infection severely disrupted the balance of gut microbiota, resulting in intestinal and brain damage. Lactobacillus spp. play a crucial role in immune regulation, and the metabolite ILA is a promising therapeutic compound for efficient and safe treatment of T. gondii infection.

Evaluation of T. gondii, rubella, and cytomegalovirus seroprevalences among female Syrian refugees in Sanliurfa, Turkiye.

INTRODUCTION: Since the Syrian Civil War began in 2011, the official number of refugees under temporary protection in Turkiye is reported to be 3,522,036 in 2023. Most of the Syrians living outside the refugee camps have worse conditions in terms of access to healthcare centers and social opportunities, compared to those living in camps. The Sanliurfa province hosts the third highest number of Syrians (370,291) in Turkiye. There are no data about the seroprevalence of Toxoplasma gondii (T. gondii), rubella (rub), or cytomegalovirus (CMV) among Syrian refugees in Sanliurfa. We aimed to investigate the seroprevalence of T. gondii, rub, and CMV infections among female Syrian refugees of reproductive age (15-49 years) living in Sanliurfa province. METHODOLOGY: A cross-sectional study was conducted in different districts of Sanliurfa. A total of 460 households were selected using the probability sampling method. One married female Syrian refugee aged between 15 and 49 years, was chosen in each household, leading to a sample size of 410 female Syrian refugees. The seropositivity of T. gondii, CMV, and rub IgM and IgG in blood samples were analyzed using enzyme immunoassays (Abbott Architect, Illinois, USA). RESULTS: The seropositivity rates of T. gondii, CMV, and rubella IgM and IgG were 4.4% and 59.8%; 3.9%; and 99%; and 1.9%, and 99.5%, respectively. CONCLUSIONS: A screening program should be implemented for T. gondii, CMV, and rub infections for Syrian refugees. Seronegative women should be vaccinated against rub and educated about the transmission and preventive routes of toxoplasmosis and CMV infection.

Research Progress on the Association between Schizophrenia and Toxoplasma gondii Infection.

Toxoplasma gondii( T. gondii or Tg), is an obligatory intracellular parasite with humans as its intermediate hosts. In recent years, significant correlations between T. gondii infection and schizophrenia have been reported, including the possible mediating mechanisms. Currently, mechanisms and hypotheses focus on central neurotransmitters, immunity, neuroinflammation, and epigenetics; however, the exact underlying mechanisms remain unclear. In this article, we review the studies related to T. gondii infection and schizophrenia, particularly the latest research progress. Research on dopamine (DA) and other neurotransmitters, the blood-brain barrier, inflammatory factors, disease heterogeneity, and other confounders is also discussed. In addition, we also summarized the results of some new epidemiological investigations.

Seropositivity of toxoplasmosis in pregnant women living with HIV/AIDS worldwide: A systematic review and meta-analysis.

BACKGROUND: Toxoplasmosis is caused by the protozoan parasite Toxoplasma gondii, a food- and water-borne zoonotic protozoan parasite that is able to infect almost all warm-blooded vertebrates. It has a major effect on public health, particularly in underdeveloped nations. Immune-competent individuals typically exhibit no symptoms or experience a mild influenza-like sickness, while there is a possibility of severe manifestation and fatal or high-risk for life-threatening diseases in immunocompromised people like pregnant women and HIV/AIDS patients and lead to severe pathological effects on the fetus. METHOD: We conducted a systematic search of databases (PubMed, Google Scholar, Science Direct, EMBASE, and Scopus) using the PRISMA criteria. We used specific keywords such as Toxoplasma gondii, Toxoplasmosis, pregnant women, prevalence, HIV/AIDS, and worldwide studies published from 2018 to 2022. We use Stata (version 14) software to estimate the pooled prevalence and heterogeneity of toxoplasmosis in pregnant women and HIV-infected people using a random-effects model and the Cochran's Q-test, respectively. The Joanna Briggs Institute Critical Appraisal Instrument and Egger's regression asymmetry test were used to assess study quality and publication bias, respectively, while the single study omission analysis was used to test the robustness of a pooled estimate. RESULTS: We included and analyzed a total of 12,887 individuals in this review. The pooled prevalence of T. gondii in this review was 40% (95% CI = 0.31-0.50). The sub-group analysis revealed that the evaluation included 11,967 pregnant women. In pregnant women, the pooled sero-prevalence was 40% (95% CI = 0.31-0.50). In pregnant women and HIV/AIDS patients, 920 individuals were evaluated, and the pooled sero-prevalence was 41% (95% CI = 0.20-0.61). CONCLUSION: This review identified an overall sero-prevalence of Toxoplasma infection of 40% among pregnant women and HIV/AIDS. The expansion of prevention and control strategies, with a primary focus on enhancing educational initiatives, is necessary to avoid reactivation and stop the spread of infection, so investigative sero-prevalence is important work among pregnant women and HIV patients. In order to achieve a comprehensive explanation of the disease condition and reach this goal, we conducted a systematic review and meta-analysis in Worldwide for future use.

Functional Characterization of Six Eukaryotic Translation Initiation Factors of Toxoplasma gondii Using the CRISPR-Cas9 System.

Eukaryotic translation initiation factors (eIFs) are crucial for initiating protein translation and ensuring the correct assembly of mRNA-ribosomal subunit complexes. In this study, we investigated the effects of deleting six eIFs in the apicomplexan parasite Toxoplasma gondii using the CRISPR-Cas9 system. We determined the subcellular localization of these eIFs using C-terminal endogenous tagging and immunofluorescence analysis. Four eIFs (RH::315150-6HA, RH::286090-6HA, RH::249370-6HA, and RH::211410-6HA) were localized in the cytoplasm, while RH::224235-6HA was localized in the apicoplast. Additionally, RH::272640-6HA was found in both the basal complex and the cytoplasm of T. gondii. Functional characterization of the six RHΔeIFs strains was conducted using plaque assay, cell invasion assay, intracellular growth assay and egress assay in vitro, and virulence assay in mice. Disruption of five eIF genes (RHΔ315150, RHΔ272640, RHΔ249370, RHΔ211410, and RHΔ224235) did not affect the ability of the T. gondii RH strain to invade, replicate, form plaques and egress in vitro, or virulence in Kunming mice (p > 0.05). However, the RHΔ286090 strain showed slightly reduced invasion efficiency and virulence (p < 0.01) compared to the other five RHΔeIFs strains and the wild-type strain. The disruption of the TGGT1_286090 gene significantly impaired the ability of tachyzoites to differentiate into bradyzoites in both type I RH and type II Pru strains. These findings reveal that the eukaryotic translation initiation factor TGGT1_286090 is crucial for T. gondii bradyzoite differentiation and may serve as a potential target for drug development and an attenuated vaccine against T. gondii.

Research progress of ubiquitin and ubiquitin-like signaling in Toxoplasma gondii.

Toxoplasmosis, a zoonotic parasitic disease caused by Toxoplasma gondii (T. gondii), is prevalent worldwide. The fact should be emphasized that a considerable proportion of individuals infected with T. gondii may remain asymptomatic; nevertheless, the condition can have severe implications for pregnant women or immunocompromised individuals. The current treatment of toxoplasmosis primarily relies on medication; however, traditional anti-toxoplasmosis drugs exhibit significant limitations in terms of efficacy, side effects, and drug resistance. The life cycles of T. gondii are characterized by distinct stages and its body morphology goes through dynamic alterations during the growth cycle that are intricately governed by a wide array of post-translational modifications (PTMs). Ubiquitin (Ub) signaling and ubiquitin-like (Ubl) signaling are two crucial post-translational modification pathways within cells, regulating protein function, localization, stability, or interactions by attaching Ub or ubiquitin-like proteins (Ubls) to target proteins. While these signaling mechanisms share some functional similarities, they have distinct regulatory mechanisms and effects. T. gondii possesses both Ub and Ubls and plays a significant role in regulating the parasite's life cycle and maintaining its morphology through PTMs of substrate proteins. Investigating the role and mechanism of protein ubiquitination in T. gondii will provide valuable insights for preventing and treating toxoplasmosis. This review explores the distinctive characteristics of Ub and Ubl signaling in T. gondii, with the aim of inspiring research ideas for the identification of safer and more effective drug targets against toxoplasmosis.

In vitro and in vivo activity evaluation and mode of action of broxaldine on Toxoplasma gondii.

Toxoplasma gondii (T. gondii) is a highly successful global parasite, infecting about one-third of the world's population and significantly affecting human life and the economy. However, current drugs for toxoplasmosis treatment have considerable side effects, and there is no specific drug to meet current needs. This study aims to evaluate the anti-T. gondii activity of broxaldine (BRO) in vitro and in vivo and explore its mechanism of action. Our results showed that compared to the control group, the invasion rate of tachyzoites in the 4 µg/mL BRO group was only 14.31%, and the proliferation rate of tachyzoites in host cells was only 1.23%. Furthermore, BRO disrupted the lytic cycle of T. gondii and reduced the size and number of cysts in vitro. A mouse model of acute toxoplasmosis reported a 41.5% survival rate after BRO treatment, with reduced parasite load in tissues and blood. The subcellular structure of T. gondii was observed, including disintegration of T. gondii, mitochondrial swelling, increased liposomes, and the presence of autophagic lysosomes. Further investigation revealed enhanced autophagy, increased neutral lipids, and decreased mitochondrial membrane potential in T. gondii treated with BRO. The results also showed a significant decrease in ATP levels. Overall, BRO demonstrates good anti-T. gondii activity in vitro and in vivo; therefore, it has the potential to be used as a lead compound for anti-T. gondii treatment.

The Effects and Mechanism of ATM Kinase Inhibitors in Toxoplasma gondii.

Toxoplasma gondii, an important opportunistic pathogen, underscores the necessity of developing novel therapeutic drugs and identifying new drug targets. Our findings indicate that the half-maximal inhibitory concentrations (IC50) of KU60019 and CP466722 (abbreviated as KU and CP) against T. gondii are 0.522 µM and 0.702 µM, respectively, with selection indices (SI) of 68 and 10. Treatment with KU and CP affects the in vitro growth of T. gondii, inducing aberrant division in the daughter parasites. Transmission electron microscopy reveals that KU and CP prompt the anomalous division of T. gondii, accompanied by cellular enlargement, nuclear shrinkage, and an increased dense granule density, suggesting potential damage to parasite vesicle transport. Subsequent investigations unveil their ability to modulate the expression of certain secreted proteins and FAS II (type II fatty acid synthesis) in T. gondii, as well as including the dot-like aggregation of the autophagy-related protein ATG8 (autophagy-related protein 8), thereby expediting programmed death. Leveraging DARTS (drug affinity responsive target stability) in conjunction with 4D-Label-free quantitative proteomics technology, we identified seven target proteins binding to KU, implicated in pivotal biological processes such as the fatty acid metabolism, mitochondrial ATP transmission, microtubule formation, and Golgi proteins transport in T. gondii. Molecular docking predicts their good binding affinity. Furthermore, KU has a slight protective effect on mice infected with T. gondii. Elucidating the function of those target proteins and their mechanism of action with ATM kinase inhibitors may potentially enhance the treatment paradigm for toxoplasmosis.

Toxoplasma gondii suppress human cord blood cell differentiation to the NK cell population.

BACKGROUND: Toxoplasma gondii is an obligate intracellular protozoan parasite that can invade all mammalian cells. It is well established that natural killer (NK) cells have critical protective roles in innate immunity during infections by intracellular pathogens. In the current study, we conducted an in vitro experiment to evaluate NK cell differentiation and activation from human umbilical cord blood mononuclear cells (UCB-MNCs) after infection with T. gondii tachyzoites. METHODS: UCB-MNCs were infected by fresh tachyzoites of type I (RH) or type II (PTG) strains of T. gondii pre-expanded in mesenchymal stem cells for 2 weeks in a medium enriched with stem cell factor, Flt3, IL-2, and IL-15. Flow cytometry analysis and western blot analysis were performed to measure the CD57+, CD56+, and Granzyme A (GZMA). RESULTS: Data revealed that incubation of UCB-MNCs with NK cell differentiation medium increased the CD57+, CD56+, and GZMA. UCB-MNCs cocultured with PTG tachyzoites showed a significant reduction of CD56+ and GZMA, but nonsignificant changes, in the levels of CD56+ compared to the control UCB-MNCs (p > .05). Noteworthy, 2-week culture of UCB-MNCs with type I (RH) tachyzoites significantly suppressed CD57+, CD56+, and GZMA, showing reduction of NK cell differentiation from cord blood cells. CONCLUSION: Our findings suggest that virulent T. gondii tachyzoites with cytopathic effects inhibit NK cell activation and eliminate innate immune responses during infection, and consequently enable the parasite to continue its survival in the host body.

The Toxoplasma secreted effector TgWIP modulates dendritic cell motility by activating host tyrosine phosphatases Shp1 and Shp2.

The obligate intracellular parasite Toxoplasma gondii causes life-threatening toxoplasmosis to immunocompromised individuals. The pathogenesis of Toxoplasma relies on its swift dissemination to the central nervous system through a 'Trojan Horse' mechanism using infected leukocytes as carriers. Previous work found TgWIP, a protein secreted from Toxoplasma, played a role in altering the actin cytoskeleton and promoting cell migration in infected dendritic cells (DCs). However, the mechanism behind these changes was unknown. Here, we report that TgWIP harbors two SH2-binding motifs that interact with tyrosine phosphatases Shp1 and Shp2, leading to phosphatase activation. DCs infected with Toxoplasma exhibited hypermigration, accompanying enhanced F-actin stress fibers and increased membrane protrusions such as filopodia and pseudopodia. By contrast, these phenotypes were abrogated in DCs infected with Toxoplasma expressing a mutant TgWIP lacking the SH2-binding motifs. We further demonstrated that the Rho-associated kinase (Rock) is involved in the induction of these phenotypes, in a TgWIP-Shp1/2 dependent manner. Collectively, the data uncover a molecular mechanism by which TgWIP modulates the migration dynamics of infected DCs in vitro.

Toxoplasma gondii infection supports the infiltration of T cells into brain tumors.

Few T cells infiltrate into primary brain tumors, fundamentally hampering the effectiveness of immunotherapy. We hypothesized that Toxoplasma gondii, a microorganism that naturally elicits a Th1 response in the brain, can promote T cell infiltration into brain tumors despite their immune suppressive microenvironment. Using a mouse genetic model for medulloblastoma, we found that T. gondii infection induced the infiltration of activatable T cells into the tumor mass and led to myeloid cell reprogramming toward a T cell-supportive state, without causing severe health issues in mice. The study provides a concrete foundation for future studies to take advantage of the immune modulatory capacity of T. gondii to facilitate brain tumor immunotherapy.

Cross-sectional study to investigate the seroprevalence and risk factors of Toxoplasma gondii among women attending the antenatal clinic in Namwala, Zambia.

BACKGROUND: Toxoplasmosis is a zoonotic parasitic disease caused by Toxoplasma gondii (T. gondii). It has a wide host range and is capable of vertical transmission in pregnant women, which may lead to undesirable pregnancy outcomes such as congenital malformations, miscarriage, premature birth and stillbirth. This study investigated the seroprevalence of T. gondii infection among pregnant women attending the antenatal clinic at Namwala District Hospital in Southern Zambia. METHODS: This was a cross-sectional study where blood was collected, and the serum was tested for Toxoplasma IgG and IgM. A questionnaire was administered to participants on demographic characteristics and risk factors. Data were entered in Microsoft Excel and exported to STATA version 14 for analysis. RESULTS: A total of 401 women were enrolled in the study from 3 March to 5 August 2021. The seroprevalence of Toxoplasma IgG was 4.2% (n=17), while the seroprevalence of Toxoplasma IgM was 0.7% (n=3). The median age was 27 (IQR: 24-30) years, and a larger proportion had primary-level education (n=223, 55.6%). The majority (81.6%) of the women were married. None of the risk factors investigated in this study were significant for T. gondii infection. CONCLUSION: There was a low seroprevalence of T. gondii infection among pregnant women in the Namwala district of Southern Province, Zambia, and regular screening may not be warranted in this population. Continued research on toxoplasmosis is recommended to understand its epidemiology across Zambia.

The effect of the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy and its relationship with toxoplasmosis.

This study aims to investigate the relationship between toxoplasmosis and this pathway, which may be effective in the formation of epilepsy by acting through the HMGB1/RAGE/TLR4/NF-κB signalling pathway in patients with idiopathic epilepsy. In the study, four different experimental groups were formed by selecting Toxoplasma gondii IgG positive and negative patients with idiopathic epilepsy and healthy controls. Experimental groups were as follows: Group 1: Epilepsy+/Toxo- (E+, T-) (n = 10), Group 2: Epilepsy-/Toxo- (E-, T-) (n = 10), Group 3: Epilepsy-/Toxo+ (E-, T+) (n = 10), Group 4: Epilepsy+/Toxo+ (E+, T+) (n = 10). HMGB1, RAGE, TLR4, TLR1, TLR2, TLR3, IRAK1, IRAK2, IKBKB, IKBKG, BCL3, IL1ß, IL10, 1 L8 and TNFα mRNA expression levels in the HMGB/RAGE/TLR4/NF-κB signalling pathway were determined by quantitative simultaneous PCR (qRT-PCR) after collecting blood samples from all patients in the groups. Statistical analysis was performed by one-way ANOVA followed by LSD post-hoc tests, and p < 0.05 was considered to denote statistical significance. The gene expression levels of HMGB1, TLR4, IL10, IL1B, IL8, and TLR2 were significantly higher in the G1 group than in the other groups (p < 0.05). In the G3 group, RAGE and BCL3 gene expression levels were significantly higher than in the other groups (p < 0.05). In the G4 group, however, IRAK2, IKBKB, and IKBKG gene expression levels were significantly higher than in the other groups (p < 0.05). HMGB1, TLR4, IRAK2, IKBKB, IL10, IL1B, IL1B, and IL8 in this signalling pathway are highly expressed in epilepsy patients in G1 and seizures occur with the stimulation of excitatory mechanisms by acting through this pathway. The signalling pathway in epilepsy may be activated by HMGB1, TLR4, and TLR2, which are considered to increase the level of proinflammatory cytokines. In T. gondii, this pathway is activated by RAGE and BCL3.

Mutual regulations between Toxoplasma gondii and type I interferon.

In the decades since the discovery, Type I interferon (IFN-I) has been intensively studied for their antiviral activity. However, increasing evidences suggest that it may also play an important role in the infection of Toxoplasma gondii, a model organism for intracellular parasites. Recent studies demonstrated that the induction of IFN-I by the parasite depends on cell type, strain genotype, and mouse strain. IFN-I can inhibit the proliferation of T. gondii, but few studies showed that it is beneficial to the growth of the parasite. Meanwhile, T. gondii also can secrete proteins that impact the pathway of IFN-I production and downstream induced interferon-stimulated genes (ISGs) regulation, thereby escaping immune destruction by the host. This article reviews the major findings and progress in the production, function, and regulation of IFN-I during T. gondii infection, to thoroughly understand the innate immune mechanism of T. gondii infection, which provides a new target for subsequent intervention and treatment.