Comprehensive Overview of Toxoplasma gondii-Induced and Associated Diseases

Designing a multi-epitope vaccine using Toxoplasma ROP5, ROP7, and SAG1 epitopes and immunogenicity evaluation against acute and chronic toxoplasmosis in BABL/c mice

This study designed and evaluated a multi-epitope DNA vaccine targeting Toxoplasma gondii immunodominant antigens-ROP5, ROP7, and SAG1-to assess its protective efficacy against acute and chronic toxoplasmosis in BALB/c mice. A bioengineered multi-epitope vaccine construct (MEVC) was synthesized by integrating computationally predicted B- and T-cell epitopes using SAPGTP linkers to ensure conformational stability and epitope accessibility. In silico analyses confirmed the MEVC's antigenicity (VaxiJen score: 0.96), non-allergenicity, solubility (GRAVY index: 0.45), and physicochemical stability (instability index: 32.14; aliphatic index: 78.3), supporting its suitability for immunization. The codon-optimized sequence (753 bp; 253 amino acids) was cloned into the pcDNA3.1(+) plasmid and amplified in Escherichia coli TOP10 cells. Thirty-six female BALB/c mice (6-8 weeks) were divided into three groups (n = 12/group) and immunized intramuscularly with 100 μg MEVC, empty vector, or phosphate-buffered saline (PBS) at weeks 0, 2, and 4. Post-immunization, mice were challenged with acute (2 × 103 RH strain tachyzoites, intraperitoneal) or chronic (10 PRU strain cysts, oral) infection. Molecular docking simulations demonstrated high-affinity binding of the MEVC to murine toll-like receptor 4 via hydrogen bonds and hydrophobic interactions, suggesting adjuvant-like immunogenicity. In vitro expression in HEK-293 cells confirmed protein synthesis, with Western blot detecting a 26 kDa immunoreactive band. MEVC-immunized mice exhibited significantly elevated anti-Toxoplasma IgG titers (1:12,800), dominated by IgG2a isotypes (P < 0.05), and robust IFN-γ production, indicative of Th1-polarized immunity. IL-4 levels remained low, confirming minimal Th2 skewing. Vaccination reduced cerebral cyst burden by 76 % (P < 0.01) in chronic infection, yet survival post-acute challenge extended only two days compared to controls. These results demonstrate partial protection against toxoplasmosis, with the MEVC eliciting cellular and humoral responses effective against chronic infection but limited efficacy in acute settings.

Assessing the therapeutic potential of silicon dioxide nanoparticles in acute and chronic toxoplasmosis in BALB/c mice

Toxoplasmosis, an infection caused by the obligate intracellular parasite Toxoplasma gondii, represents a significant global health concern, particularly for immunocompromised individuals. This study aimed to evaluate the therapeutic effects of silicon dioxide nanoparticles (SiO2-NPs) against both acute (T. gondii RH strain) and chronic (T. gondii PRU strain) infections in BALB/c mice. In the acute infection model, mice (n = 40) were infected with 104 T. gondii tachyzoites, while the chronic infection model (n = 40) involved the injection of 50 active cysts. Mice were treated with SiO2-NPs or pyrimethamine. Evaluations of parasite load and histopathological changes were conducted. The results showed that SiO2-NPs significantly reduced the number of cysts in the brain, indicating their effectiveness in controlling T. gondii proliferation. In cases of acute infection, there was a statistically significant decrease in parasite load (p < 0.01). Although there was no significant difference between the pyrimethamine and SiO2-NPs groups (p > 0.05), nanoparticles exhibited greater efficacy than pyrimethamine in acute infection. Furthermore, histopathological analysis revealed that mice were treated with SiO2-NPs displayed less severe lesions compared to the positive control group. The findings suggest that SiO2-NPs may offer a dual therapeutic advantage by reducing parasite load while also mitigating tissue damage. Further research is needed to explore the mechanisms behind the effectiveness of SiO2-NPs and to assess their long-term effects on T. gondii infections.

Toxoplasma gondii PROP1 is critical for autophagy and parasite viability during chronic infection

Macroautophagy is an important cellular process involving lysosomal degradation of cytoplasmic components, facilitated by autophagy-related proteins. In the protozoan parasite Toxoplasma gondii, autophagy has been demonstrated to play a key role in adapting to stress and the persistence of chronic infection. Despite limited knowledge about the core autophagy machinery in T. gondii, two PROPPIN family proteins (TgPROP1 and TgPROP2) have been identified with homology to Atg18/WIPI. Prior research in acute-stage tachyzoites suggests that TgPROP2 is predominantly involved in a non-autophagic function, specifically apicoplast biogenesis, while TgPROP1 may be involved in canonical autophagy. Here, we investigated the distinct roles of TgPROP1 and TgPROP2 in chronic stage T. gondii bradyzoites, revealing a critical role for TgPROP1, but not TgPROP2, in bradyzoite autophagy. Conditional knockdown of TgPROP2 did not impair bradyzoite autophagy. In contrast, TgPROP1 KO parasites had impaired autolysosome formation, reduced cyst burdens in chronically infected mice, and decreased viability. Together, our findings clarify the indispensable role of TgPROP1 to T. gondii autophagy and chronic infection.

IMPORTANCE

It is estimated that up to a third of the human population is chronically infected with Toxoplasma gondii; however, little is known about how this parasite persists long term within its hosts. Autophagy is a self-eating pathway that has recently been shown to play a key role in parasite persistence, yet few proteins that carry out this process during T. gondii chronic infection are known. Here, we provide evidence for a non-redundant role of TgPROP1, a protein important in the early steps of the autophagy pathway. Genetic disruption of TgPROP1 resulted in impaired autophagy and chronic infection of mice. Our results reveal a critical role for TgPROP1 in autophagy and underscore the importance of this pathway in parasite persistence.

Exploring glycolytic enzymes in disease: potential biomarkers and therapeutic targets in neurodegeneration, cancer and parasitic infections

Glycolysis, present in most organisms, is evolutionarily one of the oldest metabolic pathways. It has great relevance at a physiological level because it is responsible for generating ATP in the cell through the conversion of glucose into pyruvate and reducing nicotinamide adenine dinucleotide (NADH) (that may be fed into the electron chain in the mitochondria to produce additional ATP by oxidative phosphorylation), as well as for producing intermediates that can serve as substrates for other metabolic processes. Glycolysis takes place through 10 consecutive chemical reactions, each of which is catalysed by a specific enzyme. Although energy transduction by glucose metabolism is the main function of this pathway, involvement in virulence, growth, pathogen-host interactions, immunomodulation and adaptation to environmental conditions are other functions attributed to this metabolic pathway. In humans, where glycolysis occurs mainly in the cytosol, the mislocalization of some glycolytic enzymes in various other subcellular locations, as well as alterations in their expression and regulation, has been associated with the development and progression of various diseases. In this review, we describe the role of glycolytic enzymes in the pathogenesis of diseases of clinical interest. In addition, the potential role of these enzymes as targets for drug development and their potential for use as diagnostic and prognostic markers of some pathologies are also discussed.

The Potential Role of Toxoplasma gondii Infection in Multiple Sclerosis Development: A Seroepidemiological Study in North Khorasan Province, Iran

POURPOSE

This study aimed to investigate the seroepidemiological status of Toxoplasma gondii (T. gondii) infection in Multiple Sclerosis (MS) patients compared to controls.

METHODS

The present study included 98 MS patients and 100 controls. Demographic and clinical information collected through interviews, electronic medical records, and clinical examinations. Serum samples analyzed for anti-T. gondii IgG and IgM antibodies using ELISA.

RESULTS

A significant difference observed in the seroprevalence of anti-T. gondii IgG between 49 MS patients (50%) and 33 controls (33%). MS patients with seropositive anti-T. gondii IgG had significantly different age, Expanded Disability Status Scale (EDSS) scores, MS phenotypes, age of diagnosis, and age of onset compared to seronegative patients. Serum levels of anti-T. gondii IgG significantly elevated in the case group compared to the control group (277.8 ± 28.61 vs. 137.1 ± 9.52, P < 0.0001). In controls, all subjects were seronegative for anti-T. gondii IgM; three MS cases were positive, showing no significant difference in anti-T. gondii IgM seroprevalence between groups.

CONCLUSION

The study suggests a potential association between T. gondii infection and MS, indicating that anti-T. gondii IgG positivity may correlate with MS phenotypes and influence disease progression. This suggests that chronic toxoplasmosis may be risk factor for MS.

Immune dynamics throughout life in relation to sex hormones and perspectives gained from gender-affirming hormone therapy

Biological sex is closely associated with the properties and extent of the immune response, with males and females showing different susceptibilities to diseases and variations in immunity. Androgens, predominantly in males, generally suppress immune responses, while estrogens, more abundant in females, tend to enhance immunity. It is also established that sex hormones at least partially explain sex biases in different diseases, particularly autoimmune diseases in females. These differences are influenced by hormonal, genetic, and environmental factors, and vary throughout life stages. The advent of gender-affirming hormone therapy offers a novel opportunity to study the immunological effects of sex hormones. Despite the limited studies on this topic, available research has revealed that testosterone therapy in transgender men may suppress certain immune functions, such as type I interferon responses, while increasing inflammation markers like TNF-α. Transgender women on estrogen therapy also experience alterations in coagulation-related and inflammatory characteristics. Furthermore, other possible alterations in immune regulation can be inferred from the assessment of inflammatory and autoimmune markers in transgender individuals receiving hormone therapy. Understanding the complex interactions between sex hormones and the immune system, particularly through the unique perspective offered by gender-affirming hormone therapies, may facilitate the development of targeted therapies for infections and autoimmune diseases while also improving healthcare outcomes for transgender individuals. Here we review immune dynamics throughout life in both sexes and provide a summary of novel findings drawn from studies exploring gender-affirming hormone therapy.

Serological Profile of Anti-Toxoplasma gondii Antibodies in Liver Transplant Recipients

Toxoplasma gondii (T. gondii), a globally distributed obligatory intracellular opportunistic parasite that has infected one third of the world population, has different transmission routes including via organ transplantation. The liver has emerged as a frequent transplanted organ in which the transmission of T. gondii can occur between seropositive donors and seronegative recipients. Allied with immunosuppressive therapy, the presence of latent infection in recipients elevates the risk of severe toxoplasmosis. The goal of this study was to evaluate the demographic, clinical, epidemiological, and anti-T. gondii antibody profiles in liver transplant recipients. All demographic, clinical, epidemiological, and serological data were obtained from the electronic medical records of liver transplant recipients from the Liver Transplantation Service of the Hospital de Base in São José do Rio Preto, Brazil, from 2008 to 2018. Data from 48 eligible recipients (females: n = 17; males: n = 31) were evaluated. The recipients were grouped according to their T. gondii serological profiles (G1: IgM-/IgG-; G2: IgM-/IgG+; G3: IgM+/IgG+; G4: IgM+/IgG-). The overall mean age was 55.3 (±15.3) years; the age difference between women (42.7 ± 17 years) and men (62.2 ± 10.9 years) was statistically significant (p-value > 0.0001). The percentages of the serological profiles were 20 (n = 41.7%), 26 (n = 54.1%), and 2 (n = 4.2%) for G1, G2, and G3, respectively. No recipient had a serological profile for G4. Hepatosplenomegaly (47.9%), fever (35.4%), encephalopathy (20.8%), and headache (16.7%) were commonly observed symptoms. No statistically significant differences were observed between the serological group and clinical data (p-value = 0.953). The percentages of coinfection by T. gondii with hepatitis A, B, and C were 47.9%, 20.8%, and 12.5%, respectively. About 41.7% of the recipients later died. The data demonstrate that infection by T. gondii is common in liver transplant recipients, and it is not associated with the analyzed demographic, clinical, and epidemiological data.

A framework for exclusion of alternative diagnoses in sarcoidosis

Sarcoidosis is a multisystem granulomatous syndrome that arises from a persistent immune response to a triggering antigen(s). There is no "gold standard" test or algorithm for the diagnosis of sarcoidosis, making the diagnosis one of exclusion. The presentation of the disease varies substantially between individuals, in both the number of organs involved, and the manifestations seen in individual organs. These qualities dictate that health care providers diagnosing sarcoidosis must consider a wide range of possible alternative diagnoses, from across a range of presentations and medical specialties (infectious, inflammatory, cardiac, neurologic). Current guideline-based diagnosis of sarcoidosis recommends fulfillment of three criteria: 1) compatible clinical presentation and/or imaging 2) demonstration of granulomatous inflammation by biopsy (when possible) and, 3) exclusion of alternative causes, but do not provide guidance on standardized strategies for exclusion of alternative diagnoses. In this review, we provide a summary of the most common differential diagnoses for sarcoidosis involvement of lung, eye, skin, central nervous system, heart, liver, and kidney. We then propose a framework for testing to exclude alternative diagnoses based on pretest probability of sarcoidosis, defined as high (typical findings with sarcoidosis involvement confirmed in another organ), moderate (typical findings in a single organ), or low (atypical/findings suggesting of an alternative diagnosis). This work highlights the need for informed and careful exclusion of alternative diagnoses in sarcoidosis.

Efficacy of amniotic fluid, blood and urine samples for the diagnosis of toxoplasmosis in pregnant women candidates for amniocentesis using serological and molecular techniques

BACKGROUNDS

Toxoplasmosis, a prevalent parasitic infection, is primarily caused by Toxoplasma gondii (T. gondii). This infection poses a significant threat to neonates during pregnancy and individuals with compromised immune systems. Consequently, it is imperative to develop a novel diagnostic approach that combines high sensitivity with low-risk sampling to effectively manage patients. The aim of this study is to utilize serological and molecular techniques for the diagnosis of T. gondii infection in 100 pregnant women who were under the care of a gynecologist and were candidates for amniocentesis.

METHODS

During the 15-19th weeks of pregnancy, a total of 100 samples each of amniotic fluid, buffy coat, plasma, and urine simultaneously were collected from pregnant women candidates for amniocentesis in Mazandaran province, northern Iran. This study involved various assessments: (1) detecting anti-T. gondii IgM and IgG in plasma through chemiluminescence assay (2) determining IgG avidity in plasma using the Enzyme-linked immunosorbent assay technique (3) identifying of T. gondii DNA in amniotic fluid, buffy coat and urine by nested PCR (nPCR) and quantitative real-time PCR (qPCR) methods targeting the REP-529 gene, as well as genotyping using GRA6 target genes, and (4) assessing the sensitivity and specificity of the nPCR and qPCR tests.

RESULTS

Out of 100 pregnant women screened, 70 were between the ages of 31 to 40 years old. Among them, 23 and 44 had one and two previous pregnancies. Additionally, 13 and 8 women had one and two history of abortions, respectively. Following serologic testing, 52% of the individuals were positive for T. gondii antibodies. Of these, 52 samples were positive for IgG antibodies, and one sample was positive for both IgG and IgM antibodies. Notably, all 52 cases with IgG positivity exhibited a high level of IgG avidity. Regarding the molecular testing of amniotic fluid samples, two pregnant women tested positive in the nPCR assay, while three tested positive in the qPCR assay. Furthermore, genotyping revealed that all positive samples belonged to type I of the T. gondii genotype. Moreover, none of the 100 buffy coat and urine samples tested positive for T. gondii using the nPCR and qPCR techniques.

CONCLUSION

The findings of the current study suggest that serological methods alone may not be reliable in diagnosing congenital toxoplasmosis and cannot rule out the diagnosis of toxoplasmosis and must be approved by molecular tests.

Toxoplasma gondii macrophage migration inhibitory factor shows anti-Mycobacterium tuberculosis potential via AZIN1/STAT1 interaction

Mycobacterium tuberculosis (MTB) is a pathogenic bacterium, belonging to the family Mycobacteriaceae, that causes tuberculosis (TB). Toxoplasma gondii macrophage migration inhibitory factor (TgMIF), a protein homolog of macrophage migration inhibitory factor, has been explored for its potential to modulate immune responses during MTB infections. We observed that TgMIF that interacts with CD74, antizyme inhibitor 1 (AZIN1), and signal transducer and activator of transcription 1 (STAT1) modulates endocytosis, restoration of mitochondrial function, and macrophage polarization, respectively. These interactions promote therapeutic efficacy in mice infected with MTB, thereby presenting a potential route to host-directed therapy development. Furthermore, TgMIF, in combination with first-line TB drugs, significantly inhibited drug-resistant MTB strains, including multidrug-resistant TB. These results demonstrate that TgMIF is potentially a multifaceted therapeutic agent against TB, acting through immune modulation, enhancement of mitochondrial function, and dependent on STAT1 and AZIN1 pathways.

The proteasome as a drug target for treatment of parasitic diseases

The proteasome is a proteolytically active molecular machine comprising many different protein subunits. It is essential for growth and survival in eukaryotic cells and has long been considered a drug target. Here, we summarize the biology of the proteasome, the early research relating to the development of specific proteasome inhibitors (PIs) for treatment of various cancers, and their translation and eventual evolution as exciting therapies for parasitic diseases. We also highlight the development and adaptation of technologies that have allowed for a deep understanding of the idiosyncrasies of individual parasite proteasomes, as well as the preclinical and clinical advancement of PIs with remarkable therapeutic indices.

Brain -cyst-driven genes expression in Toxoplasma Gondii Tehran strain: a parasitic-immunogenicity assessment by dint of RNA-Seq

Toxoplasma gondii (T. gondii) is an obligate intracellular parasite of warm-blooded vertebrates. At present, High-throughput RNA sequencing analysis have made it possible to determine the role of effective genes in host immune response. The aim of the present study is to global transcriptome analysis of the brain of mice infected with T. gondii Tehran strain for the first time and also to evaluate the expression of effective genes in the chronic form of infection. RNA was extracted from the samples and the library was prepared and sequenced using the IlluminaNovaSeq 6000 system. After analyzing gene expression changes, the results were confirmed by real-time method. We found 125 genes that were significantly differentially expressed between infected and non-infected samples (p < 0.0005). Gene ontology analysis revealed that the expression of many genes is critical for pathways such as T cell receptor signaling pathway, Natural Killer cell mediated cytotoxicity, Lysosome and Apoptosis of the host. As infection with Tehran strain leads to chronic infection in mice, therefore, we investigated the genes effective in creating the chronic form of Toxoplasma infection. The comparative analysis of genes showed increases in the expression of genes ctla4, ccl4, cd3e, c3, lcn2, gbp5, usp18, cyba, tap1 and samhd1 in the in the infected sample, which highlights their role in causing chronic infection. RNA-seq provides a valuable tool for analyzing host transcriptomes, better understanding the parasite-host interaction, and developing future drug and vaccine targets.

Human Ocular Toxoplasmosis in Romania: History, Epidemiology, and Public Health: A Narrative Review

Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii (T. gondii), presents a significant global health concern, particularly for immunocompromised individuals and congenitally infected newborns. Despite its widespread prevalence, there are limited data on T. gondii seroprevalence and ocular toxoplasmosis in Romania. This review aims to summarize the research accomplished on the prevalence and epidemiology of human ocular toxoplasmosis in Romania. Ocular toxoplasmosis, a leading cause of infectious posterior uveitis worldwide, involves complex interactions between host immune responses and parasite factors. Clinically, it presents as focal necrotizing retinitis, characterized by active focal retinal lesions with adjacent chorioretinal scarring, often accompanied by vitreous inflammation and anterior chamber reactions. Diagnosis relies on clinical examination supported by fundus photography, optical coherence tomography (OCT), and serological assays. The authors followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards, conducting a literature review on PubMed, Google Scholar, and Scopus. Our focus was on ocular toxoplasmosis in Romania, and we used keywords and specific MeSH terms. Finally, 17 articles met all the criteria, as summarized in the PRISMA diagram. This study underscores the need for improved diagnostic methods, increased research efforts, and comprehensive public health education to mitigate the burden of toxoplasmosis and ocular toxoplasmosis in Romania.

Outcomes of Kidney Transplants From Toxoplasma-Positive Donors: An Organ Procurement and Transplant Network Database Analysis

There is a need to reconsider the acceptance of organs from donors considered suboptimal, in the absence of data. Toxoplasma antibody-positive donors (TPD) constitute one such group. The objective of our study was to compare graft survival in deceased donor renal transplant (Tx) recipients, stratified by Toxoplasma IgG status, using the Organ Procurement and Transplantation Network (OPTN) database. A log-linear event history regression model for graft failure categorized by Toxoplasma IgG status, adjusting for confounders was applied to first kidney-only Tx recipients from 2018 to 2022. Of the 51,422 Tx, 4,317 (8.4%) were from TPD. Acute rejection and graft failure (5% each) were similar between groups. Crude graft failure was 7.3 failures per 100 person-years for TPD recipients compared to 6.5 failures per 100 person-years for the Toxoplasma-negative group (p 0.008). The crude failure rate ratio was 1.14 with an adjusted hazard rate ratio of 1.04 (95% CI: 0.94, 1.15, p 0.39). In renal Tx recipients, TPD graft recipients have comparable survival to Tx from Toxoplasma-negative recipients. While caution and close monitoring of recipients post-Tx for surveillance of disseminated toxoplasmosis are still warranted, our study suggests that patients can be successfully managed using TPD organs.

RPA-CRISPR/Cas12a-LFA combined with a digital visualization instrument to detect Toxoplasma gondii in stray dogs and cats in Zhejiang province, China

Toxoplasma gondii, which causes toxoplasmosis, is prevalent in warm-blooded animals, such as cats, dogs, and humans. T. gondii causes economic losses to livestock production and represents a potential risk to public health. Dogs and cats are common hosts in the epidemiology of toxoplasmosis. The current molecular diagnostic tools for T. gondii infection require high technical skills, a laboratory environment, and complex instruments. Herein, we developed a recombinase polymerase amplification (RPA)-clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 12a (Cas12a) assay to detect T. gondii. The lowest limit of detection of the assay was 31 copies/μL for the T. gondii B1 gene. In addition, we established a visual RPA-CRISPR/Cas12a lateral flow band assay (RPA-CRISPR/Cas12a-LFA) combined with a digital visualization instrument, which minimized the problem of false-negative results for weakly positive samples and avoided misinterpretation of the results by the naked eye, making the LFA assay results more accurate. The assay established in this study could identify T. gondii within 55 min with high accuracy and sensitivity, without cross-reaction with other tested parasites. The developed assay was validated by establishing a mouse model of toxoplasmosis. Finally, the developed assay was used to investigate the prevalence of T. gondii in stray cats and dogs in Zhejiang province, Eastern China. The positive rates of T. gondii infection in stray cats and dogs were 8.0% and 4.0%, respectively. In conclusion, the RPA-CRISPR/Cas12a-LFA is rapid, sensitive, and accurate for the early diagnosis of T. gondii, showing promise for on-site surveillance.

IMPORTANCE

Toxoplasma gondii is a virulent pathogen that puts millions of infected people at risk of chronic disease reactivation. Hosts of T. gondii are distributed worldwide, and cats and dogs are common hosts of T. gondii. Therefore, rapid diagnosis of early T. gondii infection and investigation of its prevalence in stray dogs and cats are essential. Here, we established a visual recombinase polymerase amplification-clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 12a-assay combined with a lateral flow band assay and a digital visualization instrument. Detailed analyses found that the assay could be used for the early diagnosis of T. gondii without false-negative results. Moreover, we detected the prevalence of T. gondii in stray cats and dogs in Zhejiang province, China. Our developed assay provides technical support for the early diagnosis of T. gondii and could be applied in prevalence surveys of T. gondii in stray dogs and cats.

Toxoplasma gondii infection positively associated with schizophrenia: Evidences from UK Biobank cohort and case-controlled studies

Toxoplasma gondii (T. gondii) is an opportunistic pathogen affecting about 1/3 of world population. While often asymptomatic in immunocompetent individuals, it can lead to severe toxoplasmosis in immunocompromised patients. Recent research has unveiled a potential link between T. gondii infection and neuropsychiatric diseases. We implemented both a cohort study and a case control study to further identify this association. In the cohort study, we analyzed data from the UK Biobank database, which included 8814 individuals tested for T. gondii SAG1 antibodies and free of neuropsychiatric disorders at baseline. Among them, 22.52% (n = 1985) tested positive for SAG1 antibody. Over an average follow-up period of 12.26 years, Cox proportional hazards models and logistic regression analysis revealed a significant association between the SAG1 seropositivity at baseline and the incidence of schizophrenia (HR: 5.89; 95% CI: 1.69-20.53). In our case-control study, 239 patients diagnosed with schizophrenia and 455 healthy individuals were involved. Using the modified agglutination test (MAT) to detect T. gondii antibodies, logistic regression analysis showed a higher prevalence of T. gondii infection among schizophrenia patients (10.04%) compared to healthy controls (3.74%). T. gondii infection emerged as a significant risk factor for schizophrenia (OR: 3.33; 95% CI: 1.68-6.61). However, our investigations did not reveal a robust association between T. gondii infection and other neuropsychiatric conditions, including Alzheimer's disease, dementia, anxiety, depression, neurodegenerative disorders, and peripheral neurological disorders such as neurological and plexus disorders.

The role of Nrf2 signaling in parasitic diseases and its therapeutic potential

In response to invading parasites, one of the principal arms of innate immunity is oxidative stress, caused by reactive oxygen species (ROS). However, oxidative stresses play dual functions in the disease, whereby free radicals promote pathogen removal, but they can also trigger inflammation, resulting in tissue injuries. A growing body of evidence has strongly supported the notion that nuclear factor erythroid 2-related factor 2 (NRF) signaling is one of the main antioxidant pathways to combat this oxidative burst against parasites. Given the important role of NRF2 in oxidative stress, in this review, we investigate the activation mechanism of the NRF2 antioxidant pathway in different parasitic diseases, such as malaria, leishmaniasis, trypanosomiasis, toxoplasmosis, schistosomiasis, entamoebiasis, and trichinosis.

Imiquimod Reverses Chronic Toxoplasmosis-Associated Behavioral and Neurocognitive Anomalies in a Rat Model

Toxoplasma gondii is the etiologic agent of toxoplasmosis, a highly prevalent parasitosis. Toxoplasma gondii (T. gondii) transits in the brain from acute (AT) to chronic toxoplasmosis (CT), under host immune control. In immunocompromised patients, reactivation of CT is potentially life-threatening. Behavioral and neurological complications have been associated with CT. Furthermore, an effective treatment targeting CT is still lacking. We previously reported the efficacy of imiquimod against CT. Here, we demonstrate the molecular effects of imiquimod or imiquimod followed by the clinically used combination of sulfadiazine and pyrimethamine (SDZ + PYR) on CT-associated behavior in a rat model. Imiquimod decreased the number of cysts in the brains of chronically infected rats due to an induced reactivation of bradyzoites into tachyzoites. Importantly, this decrease was more pronounced in rats treated with imiquimod followed by SDZ + PYR. Rats chronically infected with T. gondii exhibited an anxiety-like behavior. Notably, treatment with imiquimod reversed this behavior aberrancy, with even a more pronounced effect with imiquimod followed by SDZ/PYR. Similarly, rats chronically infected with T. gondii exhibited learning deficits, and imiquimod alone or followed by SDZ/PYR reversed this behavior. Our results enhance our knowledge of the implications of CT on behavioral aberrancies and highlight the potency of imiquimod followed by SDZ + PYR on these CT-associated complications.

Specific Cell Targeting by Toxoplasma gondii Displaying Functional Single-Chain Variable Fragment as a Novel Strategy; A Proof of Principle

Toxoplasma gondii holds significant therapeutic potential; however, its nonspecific invasiveness results in off-target effects. The purpose of this study is to evaluate whether T. gondii specificity can be improved by surface display of scFv directed against dendritic cells' endocytic receptor, DEC205, and immune checkpoint PD-L1. Anti-DEC205 scFv was anchored to the T. gondii surface either directly via glycosylphosphatidylinositol (GPI) or by fusion with the SAG1 protein. Both constructs were successfully expressed, but the binding results suggested that the anti-DEC-SAG1 scFv had more reliable functionality towards recombinant DEC protein and DEC205-expressing MutuDC cells. Two anti-PD-L1 scFv constructs were developed that differed in the localization of the HA tag. Both constructs were adequately expressed, but the localization of the HA tag determined the functionality by binding to PD-L1 protein. Co-incubation of T. gondii displaying anti-PD-L1 scFv with tumor cells expressing/displaying different levels of PD-L1 showed strong binding depending on the level of available biomarker. Neutralization assays confirmed that binding was due to the specific interaction between anti-PD-L1 scFv and its ligand. A mixed-cell assay showed that T. gondii expressing anti-PD-L1 scFv predominately targets the PD-L1-positive cells, with negligible off-target binding. The recombinant RH-PD-L1-C strain showed increased killing ability on PD-L1+ tumor cell lines compared to the parental strain. Moreover, a co-culture assay of target tumor cells and effector CD8+ T cells showed that our model could inhibit PD1/PD-L1 interaction and potentiate T-cell immune response. These findings highlight surface display of antibody fragments as a promising strategy of targeting replicative T. gondii strains while minimizing nonspecific binding.

Comparative evaluation of silver nanoparticles and human platelet rich-plasma versus traditional therapy in the treatment of murine chronic toxoplasmosis

Toxoplasmosis is a worldwide parasitic disease infecting about one-third of the human population. At present, licensed medications are incapable of curing human chronic infection. The present work aimed to evaluate for the first time the combination between (spiramycin and human platelet rich plasma), in addition to (spiramycin and silver-nanoparticles) in treating murine experimental toxoplasmosis using parasitological, biochemical, histopathological and immunohistochemical studies. Seventy-seven Swiss albino male mice divided into seven groups according to the treatment used as follows: (GI): control negative; (GII): control infected; (GIII): spiramycin; (GIV): Silver nanoparticles (AgNPs); (GV): Human platelet-rich plasma (HPRP); (GVI): combined spiramycin and AgNPs; (GVII): combined spiramycin and HPRP. Obtained results demonstrated that (spiramycin and AgNPs) treated group showed significant reduction of T. gondii tissue cysts number, the lowest level of serum malondialdehyde, remarkable improvement in pathological changes in different tissues of mice e.g. brain and liver and weak expression of EGFR in brain tissues of mice compared to control infected group. Moreover, AgNPs administered alone produced minimal anti-Toxoplasma results, whereas their combination with spiramycin exhibited significant therapeutic efficacy. In conclusion, combination therapy of spiramycin and AgNPs may represent a unique possible adjuvant therapy for reducing the pathogenic, toxic, and inflammatory consequences of toxoplasmosis on the brain and liver tissues in immunocompetent mice, and the expression of EGFR in brain tissues of mice is a good tool for evaluating the therapeutic improvement of murine toxoplasmosis.

Adding value to banana farming: Antibody production in post-harvest leaves

Banana, a globally popular fruit, is widely cultivated in tropical and sub-tropical regions. After fruit harvest, remaining banana plant materials are low-value byproducts, mostly composted or used as fibre or for food packaging. As an aim to potentially increase farmer income, this study explored underutilised banana biomass as a novel plant tissue for production of a high-value product. Protein scFvTG130 used in this study, is an anti-toxoplasma single chain variable fragment antibody that can be used in diagnostics and neutralising the Toxoplasma gondii pathogen. Using detached banana leaves, we investigated the factors influencing the efficacy of a transient expression system using reporter genes and recombinant protein, scFvTG130. Transient expression was optimal at 2 days after detached banana leaves were vacuum infiltrated at 0.08 MPa vacuum pressure for a duration of 3 min with 0.01% (v/v) Tween20 using Agrobacterium strain GV3101 harbouring disarmed virus-based vector pIR-GFPscFvTG130. The highest concentration of anti-toxoplasma scFvTG130 antibody obtained using detached banana leaves was 22.8 µg/g fresh leaf tissue. This first study using detached banana leaf tissue for the transient expression of a recombinant protein, successfully demonstrated anti-toxoplasma scFvTG130 antibody expression, supporting the potential application for other related proteins using an underutilised detached banana leaf tissue.

Seroprevalence and Associated Risk Factors of Toxoplasma gondii in Patients Diagnosed with Schizophrenia: A Case-Control Cross Sectional Study

The protozoan parasite, Toxoplasma gondii, has been linked to several psychiatric disorders, including schizophrenia. The aim of this study was to assess the prevalence of T. gondii IgG antibodies and risk factors associated with seroprevalence in patients diagnosed with schizophrenia. This seroepidemiological study assessed 196 participants, divided into two groups. The study group consisted of 98 schizophrenic patients and was matched with 98 healthy blood donors. A questionnaire was used to gather information regarding potential risk factors associated with T. gondii seroprevalence. Results revealed a higher seroprevalence of T. gondii IgG antibodies in schizophrenic patients (69.39%, 68/98) when compared to healthy controls (51.02%, 50/98) (OR: 2.18; 95% CI: 1.21-3.9; p = 0.01). Patients with schizophrenia who consumed raw or undercooked meat (80.65%, 25/31) (OR: 3.75; 95% CI: 1.25-11.21, p = 0.02) and those with a lower educational level (77.59%, 45/58) (OR: 3.5; 95% CI: 1.59-7.54, p = 0.002) presented increased T. gondii seropositivity rates versus their control counterparts. Our findings indicate a high T. gondii IgG seroprevalence in patients diagnosed with schizophrenia compared to healthy blood donors. Factors associated with T. gondii seroprevalence were consumption of raw or uncooked meat and a lower educational attainment. This study provided the first data regarding the potential risk factors for toxoplasmosis in Romanian patients diagnosed with schizophrenia and may serve as a foundation for future research and the development of preventive strategies.

Chronic Toxoplasma gondii Infection Modulates Hearing Ability across the Adult Life Span

While several studies have shown associations between hearing disorders and congenital toxoplasmosis, the present study investigated the impact of chronic, latent Toxoplasma gondii (T. gondii) infection on hearing loss. We used a regression analysis to explore whether latent T. gondii infection modulates changes in hearing thresholds over an age range from 20 to 70 years. We analyzed audiometric data of 162 T. gondii IgG-positive and 430 T. gondii-negative participants, collected in the Dortmund Vital Study (DVS, ClinicalTrials.gov Identifier: NCT05155397), a prospective study on healthy cognitive aging. The regression analysis indicated that latent toxoplasmosis was associated with an accelerated development in hearing loss over the observed age range. Hearing loss was less frequent in IgG-positive than in IgG-negative participants up to the age of about 40 for a low (0.125-1 kHz)-frequency range. For high (2-8 kHz) frequencies, this pattern reversed for ages above 65 years. We discuss these findings on hearing function in the context of a recently proposed model, suggesting that latent toxoplasmosis can differentially affect brain functions across a lifespan.

Single and combination treatment of Toxoplasma gondii infections with a bumped kinase inhibitor and artemisone in vitro and with artemiside in experimentally infected mice

In previous studies, the artemisinin derivatives artemisone, its pro-drug artemiside and the bumped-kinase inhibitor BKI-1748 were effective against T. gondii via different modes of action. This suggests that they may act synergistically resulting in improved efficacies in vitro and in vivo. To test this hypothesis, the compounds were applied alone and in combination to T. gondii infected human fibroblast host cells in order to determine their inhibition constants and effects on cellular ultrastructure. In addition, the efficacy of either single- or combined treatments were assessed in an acute TgShSp1-oocyst infection model based on CD1 outbred mice. Whereas the IC50 of the compounds in combination (42 nM) was close to the IC50 of BKI-1748 alone (46 nM) and half of the IC50 of artemisone alone (92 nM), the IC90 of the combination was half of the values found with the single compounds (138 nM vs. ca. 270 nM). Another indication for synergistic effects in vitro were distinct alterations of the cellular ultrastructure of tachyzoites observed in combination, but not with the single compounds. These promising results could not be reproduced in vivo. There was no decrease in number of T. gondii positive brains by either treatment. However, the levels of infection in these brains, i. e. the number of tachyzoites, was significantly decreased upon BKI-1748 treatment alone, and the combination with artemiside did not produce any further decrease. The treatment with artemiside alone had no significant effects. A vertical transmission model could not be established since artemiside strongly interfered with pregnancy and caused abortion. These results show that is difficult to extrapolate from promising in vitro results to the situation in vivo.

Transcriptomic and metabolomic analyses reveal the essential nature of Rab1B in Toxoplasma gondii

BACKGROUND

The protozoan parasite Toxoplasma gondii encodes a dozen Rab proteins, which are parts of the small GTPase superfamily and regulate intracellular membrane trafficking. Our previous study showed that depletion of Rab1B caused severe defects regarding parasite growth and morphological structure, yet early defects of endocytic trafficking and vesicle sorting to the rhoptry in T. gondii are not expected to have a strong effect. To understand this discrepancy, we performed an integrated analysis at the level of transcriptomics and metabolomics.

METHODS

In the study, tetracycline-inducible TATi/Ty-Rab1B parasite line treated with ATc at three different time points (0, 18 and 24 h) was used. We first observed the morphological changes caused by Rab1B depletion via transmission electron technology. Then, high-throughput transcriptome along with non-targeted metabolomics were performed to analyze the RNA expression and metabolite changes in the Rab1B-depleted parasite. The essential nature of Rab1B in the parasite was revealed by the integrated omics approach.

RESULTS

Transmission electron micrographs showed a strong disorganization of endo-membranes in the Rab1B-depleted parasites. Our deep analysis of transcriptome and metabolome identified 2181 and 2374 differentially expressed genes (DEGs) and 30 and 83 differentially expressed metabolites (DEMs) at 18 and 24 h of induction in the tetracycline-inducible parasite line, respectively. These DEGs included key genes associated with crucial organelles that contain the rhoptry, microneme, endoplasmic reticulum and Golgi apparatus. The analysis of qRT-PCR verified some of the key DEGs identified by RNA-Seq, supporting that the key vesicular regulator Rab1B was involved in biogenesis of multiple parasite organelles. Functional enrichment analyses revealed pathways related to central carbon metabolisms and lipid metabolisms, such as the TCA cycle, glycerophospholipid metabolism and fatty acid biosynthesis and elongation. Further correlation analysis of the major DEMs and DEGs supported the role of Rab1B in biogenesis of fatty acids (e.g. myrisoleic acid and oleic acid) (R > 0.95 and P < 0.05), which was consistent with the scavenging role in biotin via the endocytic process.

CONCLUSIONS

Rab1B played an important role in parasite growth and morphology, which was supported by the replication assay and transmission electron microscopy observation. Our multi-omics analyses provided detailed insights into the overall impact on the parasite upon depletion of the protein. These analyses reinforced the role of Rab1B in the endocytic process, which has an impact on fatty acid biogenesis and the TCA cycle. Taken together, these findings contribute to our understanding of a key vesicular regulator, Rab1B, on parasite metabolism and morphological formation in T. gondii.

The interplay between toxoplasmosis and host miRNAs: Mechanisms and consequences

Toxoplasmosis is one of the highly prevalent zoonotic diseases worldwide caused by the parasite Toxoplasma gondii (T. gondii). The infection with T. gondii could pass unidentified in immunocompetent individuals; however, latent cysts remain dormant in their digestive tract, but they could be shed and excreted with feces infesting the environment. However, active toxoplasmosis can create serious consequences, particularly in newborns and infected persons with compromised immunity. These complications include ocular toxoplasmosis, in which most cases cannot be treated. Additionally, it caused many stillbirths and miscarriages. Circulating miRNAs are important regulatory molecules ensuring that the normal physiological role of various organs is harmonious. Upon infection with T. gondii, the tightly regulated miRNA profile is disrupted to favor the parasite's survival and further participate in the disease pathogenesis. Interestingly, this dysregulated profile could be useful in acute and chronic disease discrimination and in providing insights into the pathomechanisms of the disease. Thus, this review sheds light on the various roles of miRNAs in signaling pathways regulation involved in the pathogenesis of T. gondii and provides insights into the application of miRNAs clinically for its diagnosis and prognosis.

Evaluation of mono and combined nitrofurantoin therapy for toxoplasmosis in vivo using murine model

Toxoplasmosis is a frequent disease with an estimated prevalence of more than one billion human cases worldwide and over one million new infections each year. It is classified as a neglected tropical disease by the CDC since 2019. The disease may pass unnoticed in healthy individuals but could be fatal in the immunocompromised. Moreover, no effective treatment is available against the chronic form of the disease. Available anti-Toxoplasma drugs are associated with many side effects. Therefore, search for new more reliable, more efficient, and less toxic therapeutic agents is a continuous endeavor. This study assesses the potential use of nitrofurantoin, a compound with well-established antimicrobial properties, as a potential anti-Toxoplasma drug in vivo. It compares its efficacy to the commonly used anti-Toxoplasma agent spiramycin by molecular and histopathological methods in acute and chronic infection. The results demonstrate a significant ability to eliminate the parasite (P < 0.001) whether used as mono- or combined therapy with spiramycin in the acute and chronic stages. When compared to the anti-Toxoplasma drug spiramycin, nitrofurantoin achieved similar efficacy in the acute and chronic infection (P = 0.65 and P = 0.096, respectively). However, better results were obtained when using a combination of both drugs (P < 0.001). Additionally, nitrofurantoin showed good inhibitory effects on the inflammatory process in the liver, kidney, and uterus of the experimentally infected animals. In conclusion, nitrofurantoin can be considered as a potential anti-Toxoplasma agent. Nevertheless, further studies are recommended before consideration for clinical trials.

The effects of intracellular iron availability on the outcome of Toxoplasma gondii infection in mice

Toxoplasma gondii (T. gondii) is a parasite that obtains the iron it needs for its own metabolism from the host-cell iron pool. In this work, we aimed to investigate if iron supplementation or deficiency affected the course of T. gondii infection. Eighty mice were divided into four groups, each with 20 animals: Group (I): Uninfected control group. Group (II): Infected control group: injected with Phosphate buffered saline. Group (III): Infected group: received iron sucrose treatment. Group (IV): Infected group: treated with deferoxamine. Quantitative PCR studies were performed on days 3 and 8 post-infection to detect the expression of iron metabolism genes (hamp and ferroprotin) and immune-histochemical analysis to study the percentage of TNF-α and TGF-β tissue expression. Iron supplementation induced progressions of infection evident by increased tissue expression of pro-inflammatory cytokine TNF-α and downregulation of TGF-β which is mostly linked to suppression of the inflammatory process caused by T. gondii. Increased expression of TGF-β and decreased expression of TNF-α was noticed when iron deprivation occurred. On day 3, we noticed increased expression in the hamp gene with iron supplementation while it decreases when the iron supply is low. On the contrary, iron deficiency increased ferroprotin gene expression whereas supplementing decreased it. On day 8, the level of expression of these genes returned to normal levels. These observations document the potential role of iron in controlling toxoplasmosis infection and indicate that the transcription of hamp and ferroprotin in T. gondii-infected cells appears to be regulated by a sophisticated indirect mechanism.

Synthesis, characterization, and antiparasitic effects of zinc oxide nanoparticles-eugenol nanosuspension against Toxoplasma gondii infection

Background

In this study, zinc oxide nanoparticles-coated with eugenol (ZnO@Eug) were synthesized and evaluated as a nanosuspension (NSus) formulation against Toxoplasma gondii in vitro and in vivo.

Methods

An anti-Toxoplasma activity assay for ZnO@Eug NSus was conducted in vitro, ex vivo, and in vivo. FTIR spectroscopy confirmed the formation of ZnO@Eug NSus by detecting several functional groups involved; EDX and SEM demonstrated the grain of ZnO-NPs embedded with Eug and compositional purity.

Results

Surface charge (ZP) and size distribution (DLS) of ZnO@Eug NSus were determined to be -22.7 mV and 109.6 nm, respectively. According to the release kinetics, approximately 60% of the ZnO-NPs and Eug were released in the first 45 min. In the cytotoxicity assay, ZnO-NPs, Eug, and ZnO@Eug NSus had IC50 values of 71.85, 22.39, and 2.02 mg/mL, respectively. The therapeutic efficacy of ZnO@Eug against T. gondii was 56.3%, which was not significantly different from that of spiramycin (58.9%) (Positive-control). The tissue tachyzoites in the liver, spleen, and peritoneum were less than 50% in groups treated with Eug, spiramycin, and ZnO@Eug NSus compared to the control. ZnO@Eug-treated groups showed a survival rate of up to 13 days.

Conclusions

The ZnO@Eug NSus demonstrated antiparasitic activity against T. gondii with minimal toxic effects and high efficiency in increasing the survival of infected mice. The nanoformulations of ZnO-NPs incorporated with Eug could, in the future, be considered for treating toxoplasmosis in humans and animals if a detailed study was conducted to determine the precise dose and measure side effects.

Toxoplasma gondii Infection in Patients with Cardiovascular Diseases from Western Romania: A Case-Control Study

(1) Background: Toxoplasma gondii infects approximately one third of the world's human population. The seroepidemiology of T. gondii in cardiovascular patients is poorly discussed in the existing literature. We aimed to evaluate, for the first time, the seroprevalence of T. gondii in cardiovascular patients from Western Romania. (2) Methods: Serologic testing to demonstrate the presence of T. gondii antibodies was conducted in 256 patients with cardiovascular diseases and 261 matched blood donors. (3) Results: The overall seroprevalence of T. gondii antibodies was 64.06% in patients with cardiovascular diseases and 52.88% in blood donors and tended to increase with age in both groups. The seroprevalence of T. gondii antibodies was significantly higher in cardiovascular male patients (69.94%) compared to male blood donors (55.69%) (p = 0.006). When compared to the control group, a significantly higher prevalence of T. gondii antibodies was found among patients with hypertension (82.35%; p = 0.01) and unstable angina (67.56%; p = 0.02). (4) Conclusions: This study brings new epidemiological information on the prevalence of T. gondii in Romanian cardiovascular patients. T. gondii seroprevalence was significantly higher in patients with hypertension and unstable angina, suggesting that individuals with these diagnoses may be more frequently infected with T. gondii. This study may be a valuable starting point for further research to better evaluate the impact of T. gondii exposure on patients with cardiovascular diseases.

The effect of chronic experimental toxoplasmosis on some brain neurotransmitters level and behavior changes

Toxoplasma is capable of causing long-lasting brain cysts in its hosts, which can lead to physiological disturbances in brain neurotransmitters and result in changes in the host's behavior. This study aimed to investigate these changes using an experimental model. Twenty-five female Wistar rats, weighing 220-220 g and six weeks old, were selected for the study. The rats were divided into two control and experimental groups. The experimental group was injected with 5 × 105 tachyzoites of Toxoplasma gondii (virulent RH strain) intra-peritoneally. Four months after the injection, the rats were subjected to behavioral tests, including learning, memory, depression, and locomotor activity tests. The rats were then euthanized, and their brain and serum samples were analyzed for dopamine and serotonin levels. To ensure the presence of cysts in the brain tissue, a PCR test and preparation of pathological slides from the brain tissue were performed. The results showed that the amount of dopamine in the brain of the infected group was significantly higher than that of the control group, while the level of serotonin in brain of the infected group was significantly lower than that of the control group (P < 0.05). However, no significant difference was observed in the amount of these neurotransmitters in the blood of the two groups (P > 0.05). Behavioral changes were evaluated, and it was found that the learning and memory levels of the infected rats were significantly lower than those of the control group (P < 0.05), but no difference was observed in locomotor activity between the two groups (P > 0.05). This experimental infection model indicated that changes in neurotransmitter levels lead to behavior changes. CONCLUSION: The presence of parasite cysts in the brain can affect some of the host's behaviors through changes in neurotransmitter levels. Therefore, there is a possibility that there is a relationship between the presence of Toxoplasma cysts in the brain and neurological disorders. The results of this study suggest that chronic toxoplasmosis may play a role in behavior changes in psychotic diseases.

Metallic Nanoparticles and Core-Shell Nanosystems in the Treatment, Diagnosis, and Prevention of Parasitic Diseases

The usage of nanotechnology in the fight against parasitic diseases is in the early stages of development, but it brings hopes that this new field will provide a solution to target the early stages of parasitosis, compensate for the lack of vaccines for most parasitic diseases, and also provide new treatment options for diseases in which parasites show increased resistance to current drugs. The huge physicochemical diversity of nanomaterials developed so far, mainly for antibacterial and anti-cancer therapies, requires additional studies to determine their antiparasitic potential. When designing metallic nanoparticles (MeNPs) and specific nanosystems, such as complexes of MeNPs, with the shell of attached drugs, several physicochemical properties need to be considered. The most important are: size, shape, surface charge, type of surfactants that control their dispersion, and shell molecules that should assure specific molecular interaction with targeted molecules of parasites' cells. Therefore, it can be expected that the development of antiparasitic drugs using strategies provided by nanotechnology and the use of nanomaterials for diagnostic purposes will soon provide new and effective methods of antiparasitic therapy and effective diagnostic tools that will improve the prevention and reduce the morbidity and mortality caused by these diseases.

Mitochondrial ADP/ATP Carrier 1 Is Important for the Growth of Toxoplasma Tachyzoites

Metabolism associated with energy production is highly compartmentalized in eukaryotic cells. During this process, transporters that move metabolites across organelle membranes play pivotal roles. The highly conserved ADP/ATP carrier (AAC) involved in ATP and ADP exchange between the mitochondria and cytoplasm is key to linking the metabolic activities in these 2 compartments. The ATP produced in mitochondria can be exchanged with cytoplasmic ADP by AAC, thus satisfying the energy needs in the cytoplasm. Toxoplasma gondii is an obligate intracellular parasite with a wide range of hosts. Previous studies have shown that mitochondrial metabolism helps Toxoplasma to parasitize diverse host cells. Here, we identified 2 putative mitochondria ADP/ATP carriers in Toxoplasma with significant sequence similarity to known AACs from other eukaryotes. We examined the ATP transport function of TgAACs by expressing them in Escherichia coli cells and found that only TgAAC1 had ATP transport activity. Moreover, knockdown of TgAAC1 caused severe growth defects of parasites and heterologous expression of mouse ANT2 in the TgAAC1 depletion mutant restored its growth, revealing its importance for parasite growth. These results verified that TgAAC1 functions as the mitochondrial ADP/ATP carrier in T. gondii and the functional studies demonstrated the importance of TgAAC1 for tachyzoites growth. IMPORTANCE T. gondii has an efficient and flexible energy metabolism system to meet different growth needs. ATP is an energy-carrying molecule and needs to be exchanged between organelles with the assistance of transporters. However, the function of TgAACs has yet to be characterized. Here, we identified 2 putative AACs of T. gondii and verified that only TgAAC1 had ATP transport activity with expression in the intact E. coli cells. Detailed analyses found that TgAAC1 is critical for the growth of tachyzoites and TgAAC2 is dispensable. Moreover, complementation with mouse ANT2 restored the growth speed of iTgAAC1, further suggesting TgAAC1 functions as a mitochondrial ADP/ATP carrier. Our research demonstrated the importance of TgAAC1 for tachyzoites growth.

A state-of-the-art methodology for high-throughput in silico vaccine discovery against protozoan parasites and exemplified with discovered candidates for Toxoplasma gondii

Vaccine discovery against eukaryotic parasites is not trivial as highlighted by the limited number of known vaccines compared to the number of protozoal diseases that need one. Only three of 17 priority diseases have commercial vaccines. Live and attenuated vaccines have proved to be more effective than subunit vaccines but adversely pose more unacceptable risks. One promising approach for subunit vaccines is in silico vaccine discovery, which predicts protein vaccine candidates given thousands of target organism protein sequences. This approach, nonetheless, is an overarching concept with no standardised guidebook on implementation. No known subunit vaccines against protozoan parasites exist as a result of this approach, and consequently none to emulate. The study goal was to combine current in silico discovery knowledge specific to protozoan parasites and develop a workflow representing a state-of-the-art approach. This approach reflectively integrates a parasite's biology, a host's immune system defences, and importantly, bioinformatics programs needed to predict vaccine candidates. To demonstrate the workflow effectiveness, every Toxoplasma gondii protein was ranked in its capacity to provide long-term protective immunity. Although testing in animal models is required to validate these predictions, most of the top ranked candidates are supported by publications reinforcing our confidence in the approach.

Stable endocytic structures navigate the complex pellicle of apicomplexan parasites

Apicomplexan parasites have immense impacts on humanity, but their basic cellular processes are often poorly understood. Where endocytosis occurs in these cells, how conserved this process is with other eukaryotes, and what the functions of endocytosis are across this phylum are major unanswered questions. Using the apicomplexan model Toxoplasma, we identified the molecular composition and behavior of unusual, fixed endocytic structures. Here, stable complexes of endocytic proteins differ markedly from the dynamic assembly/disassembly of these machineries in other eukaryotes. We identify that these endocytic structures correspond to the 'micropore' that has been observed throughout the Apicomplexa. Moreover, conserved molecular adaptation of this structure is seen in apicomplexans including the kelch-domain protein K13 that is central to malarial drug-resistance. We determine that a dominant function of endocytosis in Toxoplasma is plasma membrane homeostasis, rather than parasite nutrition, and that these specialized endocytic structures originated early in infrakingdom Alveolata likely in response to the complex cell pellicle that defines this medically and ecologically important ancient eukaryotic lineage.

Phospholipase A and acyltransferase 4/retinoic acid receptor responder 3 at the intersection of tumor suppression and pathogen restriction

Phospholipase A and acyltransferase (PLAAT) 4 is a class II tumor suppressor with phospholipid metabolizing abilities. It was characterized in late 2000s, and has since been referred to as 'tazarotene-induced gene 3' (TIG3) or 'retinoic acid receptor responder 3' (RARRES3) as a key downstream effector of retinoic acid signaling. Two decades of research have revealed the complexity of its function and regulatory roles in suppressing tumorigenesis. However, more recent findings have also identified PLAAT4 as a key anti-microbial effector enzyme acting downstream of interferon regulatory factor 1 (IRF1) and interferons (IFNs), favoring protection from virus and parasite infections. Unveiling the molecular mechanisms underlying its action may thus open new therapeutic avenues for the treatment of both cancer and infectious diseases. Herein, we aim to summarize a brief history of PLAAT4 discovery, its transcriptional regulation, and the potential mechanisms in tumor prevention and anti-pathogen defense, and discuss potential future directions of PLAAT4 research toward the development of therapeutic approaches targeting this enzyme with pleiotropic functions.

A large-scale study on the seroprevalence of Toxoplasma gondii infection in humans in Iran

It is estimated that nearly one-third of the world's human population is infected with Toxoplasma gondii (Nicolle et Manceaux, 1908). Human infection is commonly asymptomatic, multifaceted, and can manifest in severe pathological forms in congenital toxoplasmosis and immunocompromised individuals. This study attempted to recognise the seroprevalence of T. gondii infection in Iranian residents referred to medical laboratories for toxoplasmosis tests throughout the country. This retrospective cross-sectional study was conducted from 2015 to 2019 on individuals referred to diagnostic laboratories in 26 provinces, and these laboratories sent their samples to the referral centres. Accordingly, data associated with serodiagnosis of toxoplasmosis, age, sex, anti-T. gondii IgG, and IgM status in Iranian residents were collected from two referral diagnostic laboratories. All individuals were evaluated using the antibody immunocapture-chemiluminescence assay (CLIA) method with the Immulite^®2000s XPi system. In this study, the first large-scale assay of T. gondii infection in Iran, an overall seroprevalence of 30.4% was among 35,047 patients examined. The highest IgM seropositivity rate was in the 10-20 years old patients. In addition, this study showed a very different prevalence of T. gondii across the country, highest in the humid areas, such as the Caspian Sea basin in the North, and the North West with seroprevalence of 48.6%.

In Vitro Activity of Essential Oils from Piper Species (Piperaceae) against Tachyzoites of Toxoplasma gondii

Toxoplasmosis is a tropical and neglected disease caused by the parasitic protozoa Toxplasma gondii. Conventional treatment with sulfadiazine and pyrimethamine plus folinic acid, has some drawbacks, such as inefficacy in the chronic phase, toxic side effects, and potential cases of resistance have been observed. In this study, the activity of essential oils (EOs) from three Piper species and their main constituents, including α-Pinene (Piper lindbergii and P. cernuum), β-Pinene (P. cernuum), and dillapiole (P. aduncum), were evaluated against tachyzoites of T. gondii. α-Pinene was more active [(IC₅₀ 0.3265 (0.2958 to 0.3604) μg/mL)] against tachyzoites than P. lindbergii EO [0.8387 (0.6492 to 1.084) μg/mL]. Both α-Pinene and P. lindbergii EO exhibited low cytotoxicity against NHDF cells, with CC₅₀ 41.37 (37.64 to 45.09) µg/mL and 83.80 (75.42 to 91.34) µg/mL, respectively, suggesting they could be of potential use against toxoplasmosis.

Treatments of Mycobacterium tuberculosis and Toxoplasma gondii with Selenium Nanoparticles

Toxoplasma gondii and Mycobacterium tuberculosis are pathogens that are harmful to humans. When these diseases interact in humans, the result is typically fatal to the public health. Several investigations on the relationship between M. tuberculosis and T. gondii infections have found that there is a strong correlation between them with each infection having a reciprocal effect on the other. TB may contribute to the reactivation of innate toxoplasmosis or enhance susceptibility to a new infection, and toxoplasma co-infection may worsen the severity of pulmonary tuberculosis. As a consequence, there is an earnest and urgent necessity to generate novel therapeutics that can subdue these challenges. Selenium nanostructures' compelling properties have been shown to be a successful treatment for Mycobacterium TB and Toxoplasma gondii. Despite the fact that selenium (Se) offers many health advantages for people, it also has a narrow therapeutic window; therefore, consuming too much of either inorganic or organic compounds based on selenium can be hazardous. Compared to both inorganic and organic Se, Se nanoparticles (SeNPs) are less hazardous. They are biocompatible and excellent in selectively targeting specific cells. As a consequence, this review conducted a summary of the efficacy of biogenic Se NPs in the treatment of tuberculosis (TB) and toxoplasmosis. Mycobacterium tuberculosis, Toxoplasma gondii, and their co-infection were all briefly described.

Molecular characterization and genotyping of Toxoplasma gondii in free-living animals in Iran: Effect of One Health

To understand the transmission of Toxoplasma gondii, this parasite's genetic diversity distribution in free-living hosts is essential. This research's objective is the molecular genotyping of T. gondii isolates from the brain and muscles of Columbidae, Corvidae, Rattus, and Felidae of Mianeh County, East-Azerbaijan Province, Northwest Iran. Three hundred fifty samples were taken. For the genotyping of T. gondii, the GRA6 gene was amplified and digested by the Tru1I (MseI) enzyme. Results of RFLP were confirmed by sequencing and phylogenetic analysis. In total, 52%, 34%, 24%, and 50% of Columbidae, Corvidae, Rattus, and Felidae were positive for T. gondii DNA, respectively. All isolated Columbidae were identified as genotype III (100%). Also, 94.1% and 5.9% of Corvidae isolates, 84.4% and 15.6% of the Rattus isolates, and 51.7% and 48.3% of the Felidae isolates belonged to genotypes III and II, respectively. This study is the first to evaluate genetic similarity and phylogenetic analysis between many definitive and intermediated hosts in northwestern Iran. The finding indicates that the T. gondii cycle is maintained among these hosts. As a result, their presence in the environment can be a risk factor for transmitting the infection to humans. Due to demographic and geographic differences in various regions, further studies are required to determine the genetic population structure.

Study on the antagonistic effects of koumiss on Toxoplasma gondii infection in mice

Toxoplasma gondii is an important food-borne zoonotic parasite, and approximately one-third of people worldwide are positive for T. gondii antibodies. To date, there are no specific drugs or vaccines against T. gondii. Therefore, developing a new safe and effective method has become a new trend in treating toxoplasmosis. Koumiss is rich in probiotics and many components that can alleviate the clinical symptoms of many diseases via the functional characteristics of koumiss and its regulation of intestinal flora. To investigate the antagonistic effect of koumiss on T. gondii infection, the model of acute and chronic T. gondii infection was established in this study. The survival rate, SHIRPA score, serum cytokine levels, brain cyst counts, β-amyloid deposition and intestinal flora changes were measured after koumiss feeding. The results showed that the clinical symptoms of mice were improved at 6 dpi and that the SHIRPA score decreased after koumiss feeding (P &lt; 0.05). At the same time, the levels of IL-4, IFN-γ and TNF-α decreased (P &lt; 0.001, P &lt; 0.001, P &lt; 0.01). There was no significant difference of survival rate between koumiss treatment and the other groups. Surprisingly, the results of chronic infection models showed that koumiss could significantly reduce the number of brain cysts in mice (P &lt; 0.05), improve β-amyloid deposition in the hippocampus (P &lt; 0.01) and decrease the levels of IFN-γ and TNF-α (P &lt; 0.01, P &lt; 0.05). Moreover, koumiss could influence the gut microbiota function in resisting T. gondii infection. In conclusion, koumiss had a significant effect on chronic T. gondii infection in mice and could improve the relevant indicators of acute T. gondii infection in mice. The research provides new evidence for the development of safe and effective anti-T. gondii methods, as well as a theoretical basis and data support for the use of probiotics against T. gondii infection and broadened thoughts for the development and utilization of koumiss.

Toxoplasma gondii in Foods: Prevalence, Control, and Safety

Toxoplasma gondii is an obligate intracellular parasite that causes toxoplasmosis, with approximately one third of the population around the world seropositive. The consumption of contaminated food is the main source of infection. These include meat products with T. gondii tissue cysts, and dairy products with tachyzoites. Recently, contamination has been detected in fresh products with oocysts and marine products. Despite the great health problems that are caused by T. gondii, currently there are no standardized methods for its detection in the food industry. In this review, we analyze the current detection methods, the prevalence of T. gondii in different food products, and the control measures. The main detection methods are bioassays, cell culture, molecular and microscopic techniques, and serological methods, but some of these do not have applicability in the food industry. As a result, emerging techniques are being developed that are aimed at the detection of multiple parasites simultaneously that would make their application more efficient in the industry. Since the prevalence of this parasite is high in many products (meat and milk, marine products, and vegetables), it is necessary to standardize detection methods, as well as implement control measures.

The association between Toxoplasma infection and mortality: the NHANES epidemiologic follow-up study

Background

Toxoplasma gondii has been reported to be associated with higher mortality in patients with schizophrenia. This study aimed to explore the relationship between T. gondii infection and 25-year mortality based on data from the Third National Health and Nutrition Examination Survey (NHANES III) database.

Methods

Cases with serum T. gondii antibody test results were included in this study and the corresponding mortality dataset was obtained from the US National Center for Health Statistics (NCHS). Propensity score matching (PSM) was used to match age and sex between groups. The Cox proportional hazards model was used to evaluate the effect of T. gondii infection on mortality.

Results

A total of 14,181 cases were included in the analysis, of which 3831 (27.0%) were seropositive for T. gondii antibody. The median follow-up time of the whole cohort was 22.5 (interquartile range 16.3, 24.5) years. A total of 5082 deaths were observed in this cohort, a mortality rate of 35.8%. All-cause mortality was significantly higher in the seropositive group than in the seronegative group (50.0% vs 30.6%, P < 0.001). Kaplan–Meier analysis showed a significant difference in the survival time between two groups before and after PSM. Multivariate analysis showed that T. gondii infection was independently associated with higher all-cause mortality after adjusting for potential confounders.

Conclusions

Toxoplasma gondii infection is associated with higher mortality in general population.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05398-1.

Emulating interactions between microorganisms and tumor microenvironment to develop cancer theranostics

The occurrence of microorganisms has been confirmed in the tumor microenvironment (TME) of many different organs. Microorganisms (e.g., phage, virus, bacteria, fungi, and protozoa) present in TME modulate TME to inhibit or promote tumor growth in species-dependent manners due to the special physiological and pathological features of each microorganism. Such microorganism-TME interactions have recently been emulated to turn microorganisms into powerful cancer theranostic agents. To facilitate scientists to explore microorganisms-TME interactions further to develop improved cancer theranostics, here we critically review the characteristics of different microorganisms that can be found in TME, their interactions with TME, and their current applications in cancer diagnosis and therapy. Clinical trials of using microorganisms for cancer theranostics are also summarized and discussed. Moreover, the emerging technology of whole-metagenome sequencing that can be employed to precisely determine microbiota spectra is described. Such technology enables scientists to gain an in-depth understanding of the species and distributions of microorganisms in TME. Therefore, scientists now have new tools to identify microorganisms (either naturally present in or introduced into TME) that can be used as effective probes, monitors, vaccines, or drugs for potentially advancing cancer theranostics to clinical applications.

Impact of Plant-Based Foods and Nutraceuticals on Toxoplasma gondii Cysts: Nutritional Therapy as a Viable Approach for Managing Chronic Brain Toxoplasmosis

Toxoplasma gondii is an obligate intracellular parasite that mainly infects warm-blooded animals including humans. T. gondii can encyst and persist chronically in the brain, leading to a broad spectrum of neurological sequelae. Despite the associated health threats, no clinical drug is currently available to eliminate T. gondii cysts. In a continuous effort to uncover novel therapeutic agents for these cysts, the potential of nutritional products has been explored. Herein, we describe findings from in vitro and in vivo studies that support the efficacy of plant-based foods and nutraceuticals against brain cyst burden and cerebral pathologies associated with chronic toxoplasmosis. Finally, we discuss strategies to increase the translatability of preclinical studies and nutritional products to address whether nutritional therapy can be beneficial for coping with chronic T. gondii infections in humans.