Direct and Indirect Inhibition Effects of Resveratrol against Toxoplasma gondii Tachyzoites In Vitro

Overexpression of the potato VQ31 enhances salt tolerance in Arabidopsis

Plant-specific VQ proteins have crucial functions in the regulation of plant growth and development, as well as in plant abiotic stress responses. Their roles have been well established in the model plant Arabidopsis thaliana; however, the functions of the potato VQ proteins have not been adequately investigated. The VQ protein core region contains a short FxxhVQxhTG amino acid motif sequence. In this study, the VQ31 protein from potato was cloned and functionally characterized. The complete open reading frame (ORF) size of StVQ31 is 672 bp, encoding 223 amino acids. Subcellular localization analysis revealed that StVQ31 is located in the nucleus. Transgenic Arabidopsis plants overexpressing StVQ31 exhibited enhanced salt tolerance compared to wild-type (WT) plants, as evidenced by increased root length, germination rate, and chlorophyll content under salinity stress. The increased tolerance of transgenic plants was associated with increased osmotic potential (proline and soluble sugars), decreased MDA accumulation, decreased total protein content, and improved membrane integrity. These results implied that StVQ31 overexpression enhanced the osmotic potential of the plants to maintain normal cell growth. Compared to the WT, the transgenic plants exhibited a notable increase in antioxidant enzyme activities, reducing cell membrane damage. Furthermore, the real-time fluorescence quantitative PCR analysis demonstrated that StVQ31 regulated the expression of genes associated with the response to salt stress, including ERD, LEA4-5, At2g38905, and AtNCED3. These findings suggest that StVQ31 significantly impacts osmotic and antioxidant cellular homeostasis, thereby enhancing salt tolerance.

Impact of resveratrol and zinc on biomarkers of oxidative stress induced by Trichinella spiralis infection

Trichinellosis is a re-emerging worldwide foodborne zoonosis. Oxidative stress is one of the most common detrimental effects caused by trichinellosis. In addition, Trichinella infection poses an infinite and major challenge to the host's immune system. Resistance and side effects limit the efficiency of the existing anti-trichinella medication. Given that concern, this work aimed to investigate the anti-helminthic, antioxidant, anti-inflammatory and immunomodulatory effects of resveratrol and zinc during both phases of Trichinella spiralis infection. Sixty-four Swiss albino mice were divided into four equal groups: non-infected control, infected control, infected and treated with resveratrol, and infected and treated with zinc. Animals were sacrificed on the 7th and 35th days post-infection for intestinal and muscular phase assessments. Drug efficacy was assessed by biochemical, parasitological, histopathological, immunological, and immunohistochemical assays. Resveratrol and zinc can be promising antiparasitic, antioxidant, anti-inflammatory, and immunomodulatory agents, as evidenced by the significant decrease in parasite burden, the significant improvement of liver and kidney function parameters, the increase in total antioxidant capacity (TAC), the reduction of malondialdehyde (MDA) level, the increase in nuclear factor (erythroid-derived 2)-like-2 factor expression, and the improvement in histopathological findings. Moreover, both drugs enhanced the immune system and restored the disturbed immune balance by increasing the interleukin 12 (IL-12) level. In conclusion, resveratrol and zinc provide protection for the host against oxidative harm and the detrimental effects produced by the host's defense response during Trichinella spiralis infection, making them promising natural alternatives for the treatment of trichinellosis.

Polyalthic Acid from Copaifera lucens Demonstrates Anticariogenic and Antiparasitic Properties for Safe Use

This study aimed at evaluating the potential of Copaifera lucens, specifically its oleoresin (CLO), extract (CECL), and the compound ent-polyalthic acid (PA), in combating caries and toxoplasmosis, while also assessing its toxicity. The study involved multiple assessments, including determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against cariogenic bacteria. CLO and PA exhibited MIC and MBC values ranging from 25 to 50 μg/mL, whereas CECL showed values equal to or exceeding 400 μg/mL. PA also displayed antibiofilm activity with minimum inhibitory concentration of biofilm (MICB50) values spanning from 62.5 to 1000 μg/mL. Moreover, PA effectively hindered the intracellular proliferation of Toxoplasma gondii at 64 μg/mL, even after 24 h without treatment. Toxicological evaluations included in vitro tests on V79 cells, where concentrations ranged from 78.1 to 1250 μg/mL of PA reduced colony formation. Additionally, using the Caenorhabditis elegans model, the lethal concentration (LC50) of PA was determined as 1000 μg/mL after 48 h of incubation. Notably, no significant differences in micronucleus induction and the NDI were observed in cultures treated with 10, 20, or 40 μg/mL of CLO. These findings underscore the safety profile of CLO and PA, highlighting their potential as alternative treatments for caries and toxoplasmosis.

Resveratrol against Echinococcus sp.: Discrepancies between In Vitro and In Vivo Responses

In an attempt to find new anti-echinococcal drugs, resveratrol (Rsv) effectiveness against the larval stages of Echinococcus granulosus and E. multilocularis was evaluated. The in vitro effect of Rsv on parasites was assessed via optical and electron microscopy, RT-qPCR and immunohistochemistry. In vivo efficacy was evaluated in murine models of cystic (CE) and alveolar echinococcosis (AE). The impact of infection and drug treatment on the mouse bone marrow hematopoietic stem cell (HSC) population and its differentiation into dendritic cells (BMDCs) was investigated via flow cytometry and RT-qPCR. In vitro treatment with Rsv reduced E. granulosus metacestode and protoscolex viability in a concentration-dependent manner, caused ultrastructural damage, increased autophagy gene transcription, and raised Eg-Atg8 expression while suppressing Eg-TOR. However, the intraperitoneal administration of Rsv was not only ineffective, but also promoted parasite development in mice with CE and AE. In the early infection model of AE treated with Rsv, an expansion of HSCs was observed followed by their differentiation towards BMCDs. The latter showed an anti-inflammatory phenotype and reduced LPS-stimulated activation compared to control BMDCs. We suggest that Rsv ineffectiveness could have been caused by the low intracystic concentration achieved in vivo and the drug's hormetic effect, with opposite anti-parasitic and immunomodulatory responses in different doses.

Evaluating the inhibitory effect of resveratrol on the multiplication of several Babesia species and Theileria equi on in vitro cultures, and Babesia microti in mice

Introduction: Histone post-translational modification is one of the most studied factors influencing epigenetic regulation of protozoan parasite gene expression, which is mediated by histone deacetylases (KDACs) and acetyltransferases (KATs). Objective and methods: The present study investigated the role of resveratrol (RVT) as an activator of histone deacetylases in the control of various pathogenic Babesia sp. and Theileria equi in vitro, as well as B. microti infected mice in vivo using fluorescence assay. Its role in mitigating the side effects associated with the widely used antibabesial drugs diminazene aceturate (DA) and azithromycin (AZM) has also been investigated. Results: The in vitro growth of B. bovis, B. bigemina, B. divergens, B. caballi and Theileria equi (T. equi) was significantly inhibited (P < 0.05) by RVT treatments. The estimated IC50 values revealed that RVT has the greatest inhibitory effects on B. bovis growth in vitro, with an IC50 value of 29.51 ± 2.46 µM. Reverse transcription PCR assay showed that such inhibitory activity might be attributed to resveratrol's stimulatory effect on B. bovis KDAC3 (BbKADC3) as well as its inhibitory effect on BbKATS. RVT causes a significant decrease (P < 0.05) in cardiac troponin T (cTnT) levels in heart tissue of B. microti- infected mice, thereby indicating that RVT may play a part in reducing the cardiotoxic effects of AZM. Resveratrol showed an additive effect with imidocarb dipropionate in vivo. Treatment of B. microti-infected mice with a combined 5 mg/kg RVT and 8.5 mg/kg ID resulted in an 81.55% inhibition at day 10 postinoculation (peak of parasitemia). Conclusion: Our data show that RVT is a promising antibabesial pharmacological candidate with therapeutic activities that could overcome the side effects of the currently used anti-Babesia medications.

Mefloquine loaded niosomes as a promising approach for the treatment of acute and chronic toxoplasmosis

Toxoplasmosis is a disease with a worldwide distribution and significant morbidity and mortality. In search of effective treatment, mefloquine (MQ) was repurposed and loaded with niosomes to treat acute and chronic phases of toxoplasmosis in experimental mice. Mice were orally inoculated with 20 cysts of Toxoplasma gondii (ME 49 strain) for the acute model of infection and 10 cysts for the chronic model of infection. Infected mice were dosed with MQ solution or MQ-niosomes at 50 mg/kg/day, starting from the second day post-infection (PI) (acute model) or the fifth week PI (chronic model), and this was continued for six consecutive days. The effects of MQ solution and MQ-niosomes were compared with a pyrimethamine/sulfadiazine (PYR/SDZ) dosing combination as mortality rates, brain cyst number, inflammatory score, and immunohistochemical studies that included an estimation of apoptotic cells (TUNEL assays). In the acute infection model, MQ solution and MQ-niosomes significantly reduced the mortality rate from 45% to 25 and 10%, respectively, compared with infected untreated controls, and decreased the number of brain cysts by 51.5% and 66.9%, respectively. In the chronic infection model, cyst reduction reached 80.9% and 12.3% for MQ solution and MQ-niosomes treatments, respectively. MQ-niosomes significantly decreased inflammation induced by acute or chronic T. gondii infection. Additionally, immunohistochemical analysis revealed that MQ solution and MQ-niosomes significantly increased the number of TUNEL-positive cells in brain tissue, indicative of induction of apoptosis. Collectively, these results indicate that MQ-niosomes may provide a useful delivery strategy to treat both acute and chronic toxoplasmosis.

The role of SIRT1 in the process of Toxoplasma gondii infection of RAW 264.7 macrophages

Toxoplasma gondii is an opportunistic pathogenic protozoan that can infect almost all kinds of warm-blooded animals, including humans. T. gondii can evade the host's immune response, a process known as immune evasion. Our main objective was to evaluate the role played by Sirtuin1 (SIRT1) [one of the sirtuins (SIRTs) that are a family of nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases (HDACs)] in the T. gondii infection of RAW264.7 macrophages. In this study, we evaluated and observed alterations in the activity, expression, and localization of SIRT1 and assessed its involvement in the CD154/IFN-γ (CD40 ligand/interferon gamma) killing pathway and in autophagy during T. gondii infection. The inhibition of SIRT1 in host cells effectively reduced the number of intracellular tachyzoites, and the mechanism behind this effect might be the upregulation of IRGM1 [murine ortholog of IRGM (immunity-related GTPase family M)] and the initiation of autophagy. To the best of our knowledge, our study is the first to prove that T. gondii infection upregulates SIRT1 in RAW264.7 cells and that the inhibition of SIRT1 reduces the number of intracellular tachyzoites. Moreover, the upregulation of IRGM1 and the activation of autophagy may contribute to the intracellular inhibition of T. gondii caused by SIRT1 inhibition.

Modulation of autophagy as a therapeutic strategy for Toxoplasma gondii infection

Toxoplasma gondii infection is a severe health threat that endangers billions of people worldwide. T. gondii utilizes the host cell membrane to form a parasitophorous vacuole (PV), thereby fully isolating itself from the host cell cytoplasm and making intracellular clearance difficult. PV can be targeted and destroyed by autophagy. Autophagic targeting results in T. gondii killing via the fusion of autophagosomes and lysosomes. However, T. gondii has developed many strategies to suppress autophagic targeting. Accordingly, the interplay between host cell autophagy and T. gondii is an emerging area with important practical implications. By promoting the canonical autophagy pathway or attenuating the suppression of autophagic targeting, autophagy can be effectively utilized in the development of novel therapeutic strategies against T gondii. Here, we have illustrated the complex interplay between host cell mediated autophagy and T. gondii. Different strategies to promote autophagy in order to target the parasite have been elucidated. Besides, we have analyzed some potential new drug molecules from the DrugBank database using bioinformatics tools, which can modulate autophagy. Various challenges and opportunities focusing autophagy mediated T. gondii clearance have been discussed, which will provide new insights for the development of novel drugs against the parasite.

Anti-parasitic effects of resveratrol on protoscolices and hydatid cyst layers

The main goal of the current study was to evaluate the effectiveness of resveratrol (RESV) on protoscolices and hydatid cysts of Echinococcus granolosus. Echinococcus granolosus protoscolices and hydatid cyst were exposed to RPMI, DMSO, formalin, mebendazole, and different concentrations of RESV in vitro. Then, viability, GGT, and caspase-3 activity of protoscolices were evaluated using light microscopy, colorimetric, and enzymatic assay, respectively. Tissue changes and expression of caspase-3 apoptosis were analyzed on the hydatid cyst wall by histologic and immunohistochemistry methods. The cell toxicity effect of RESV was evaluated on mouse PBMCs by Annexin V-FITC assay. The RESV-treated protoscolices showed loss of viability, increased gamma-glutamyl transpeptidase, and caspase-3 activity with significant differences compared to all control groups (P < 0.05). Dose and time dependence of mortality, GGT, and caspase-3 enzymatic activity was confirmed in the protoscolices of Echinococcus granulosus treated by RESV. Also, the tissue changes and apoptosis were prominent in RESV-treated hydatid cyst layers; however, tissue changes were only time-dependent, and RESV concentration had no apparent effect on tissue. In cell toxicity evaluation, RESV is safe without any significant apoptosis induction from 31.5 to 250 μg/ml; however, it was significant at 350 and 500 μg/ml in PBMCs.

The anti-Toxoplasma activity of the plant natural phenolic compound piceatannol

Toxoplasma gondii is an obligate intracellular protozoan that infects the nucleated cells of warm-blooded animals and causes life-threatening disease in immunocompromised patients. Due to the limited effectiveness and prominent side effects of existing drugs, there is an urgent need to develop new therapeutic options against T. gondii. Piceatannol is a natural plant compound with multiple functions such as antibacterial, antileukemic and antiparasitic activities. In the present study, the anti-T. gondii activity of piceatannol was evaluated. Piceatannol potently inhibited Toxoplasma with a half-maximal effective concentration (EC₅₀) of 28.10 μM. Piceatannol showed a significant inhibitory effect on intracellular proliferation, inhibiting intracellular parasites at a rate of 98.9% when treatment with 100 μM piceatannol. However, the invasion ability of tachyzoites was not affected by piceatannol. By immunofluorescence assay, we noted that the parasite showed abnormalities in cell division after exposure to piceatannol. To determine the in vivo effect of piceatannol on acute infection, a model was established by infecting BALB/c mice with the virulent RH strain of T. gondii. Mice infected with 500 tachyzoites showed a significant therapeutic effect when treated with 15 mg/kg of piceatannol. These results suggest that piceatannol is a promising drug for the treatment of T. gondii.

Resveratrol modulates Toxoplasma gondii infection induced liver injury by intervening in the HMGB1/TLR4/NF-κB signaling pathway

Toxoplasma gondii (T. gondii) is an obligate intracellular parasite that can cause liver diseases in the host, including hepatitis and hepatomegaly. High mobility group box 1 (HMGB1) is the main inflammatory mediator causing cell injury or necrosis. HMGB1 binds to toll like receptor 4 (TLR4), then activates the nuclear factor-κB (NF-κB) signaling pathway, which promotes the release of inflammatory factors. Our previous studies showed that HMGB1 mediated TLR4/NF-κB signaling pathway plays an important role in liver injury induced by T. gondii infection. Resveratrol (RSV) is a small polyphenol, which has anti-inflammatory, anti-cancer, anti-T. gondii effect. However, the effect of RSV on liver injury caused by T. gondii infection is unclear. This study used the RH strain tachyzoites of T. gondii to infect murine liver line, NCTC-1469 cells to establish an in vitro model and acute infection of mice for the in vivo model to explore the protective effect of RSV on liver injury induced by T. gondii infection. The results showed that RSV inhibited the proliferation of T. gondii in the liver, reduced the alanine aminotransferase/aspartate aminotransferase levels and pathological liver damage. Additionally, RSV inhibited the production of tumor necrosis factor-α, inducible nitric oxide synthase and HMGB1 by interfering with the TLR4/NF-κB signaling pathway. These results indicate that RSV can protect liver injury caused by T. gondii infection by intervening in the HMGB1/TLR4/NF-κB signaling pathway. This study will provide a theoretical basis for RSV treatment of T. gondii infection induced liver injury.

Moringa oleifera extract promotes apoptosis-like death in Toxoplasma gondii tachyzoites in vitro

Toxoplasma gondii is the causative agent of toxoplasmosis, and an important problem of public health. The current treatment for toxoplasmosis is the combination of pyrimethamine and sulphadiazine, which do not act in the chronic phase of toxoplasmosis and have several side-effects. This study evaluated the anti-T. gondii activity and potential mechanism of Moringa oleifera seeds’ aqueous extract in vitro. The concentration of M. oleifera extract in HeLa cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability assays. The presence of T. gondii was assessed by quantitative polymerase chain reaction and toluidine blue staining. Pyrimethamine and sulphadiazine were used as drug controls. Modifications in T. gondii morphology and ultrastructure were observed by electron microscopy. In vitro, the M. oleifera extract had no toxic effect on HeLa cells at concentrations below 50 μg mL−1. Moringa oleifera extract inhibits T. gondii invasion and intracellular proliferation with similar results for sulphadiazine + pyrimethamine, and also shows cellular nitric oxide production at a concentration of 30 μg mL−1. Electron microscopy analyses indicated structural and ultrastructural modifications in tachyzoites after treatment. We also observed an increase in reactive oxygen species production and a loss of mitochondrial membrane integrity. Nile Red staining assays demonstrated a lipid accumulation. Annexin V–fluorescein isothiocyanate and propidium iodide staining demonstrated that the main action of M. oleifera extract in T. gondii tachyzoites was compatible with late apoptosis. In conclusion, M. oleifera extract has anti-T. gondii activity in vitro and might be a promising substance for the development of a new anti-T. gondii drug.

Myrislignan Induces Redox Imbalance and Activates Autophagy in Toxoplasma gondii

Toxoplasma gondii (T. gondii) is an important health problem in human and animals, and the highlighting side effects of launched therapeutic chemicals cannot be ignored. Thus, it is urgent to develop new drugs to against the infection. Myrislignan originated from nutmeg exhibited excellent anti-T. gondii activity in vitro and in vivo, and was able to destroy mitochondrial function. However, the exact mechanism of action is still unknown. In this study, combining RNAs deep-sequencing analysis and surface plasmon resonance (SPR) analysis, the differentially expressed genes (DEGs) and high affinity proteins suggested that myrislignan may affect the oxidation-reduction process of T. gondii. Furthermore, the upregulating ROS activity after myrislignan incubation verified that myrislignan destroyed the oxidant-antioxidant homeostasis of tachyzoites. Transmission electron microscopy (TEM) indicated that myrislignan induced the formation of autophagosome-like double-membrane structure. Moreover, monodansyl cadaverine (MDC) staining and western blot further illustrated autophagosome formation. Myrislignan treatment induced a significant reduction in T. gondii by flow cytometry analysis. Together, these findings demonstrated that myrislignan can induce the oxidation-reduction in T. gondii, lead to the autophagy, and cause the death of T. gondii.

Licarin-B Exhibits Activity Against the Toxoplasma gondii RH Strain by Damaging Mitochondria and Activating Autophagy

Toxoplasma gondii is an obligate intracellular pathogen that infects warm-blooded animals and humans. However, side effects limit toxoplasmosis treatment, and new drugs with high efficiency and low toxicity need to be developed. Natural products found in plants have become a useful source of drugs for toxoplasmosis. In this study, twenty natural compounds were screened for anti-T. gondii activity by Giemsa staining or real-time fluorescence quantitative polymerase chain reaction (qPCR) in vitro. Among these, licarin-B from nutmeg exhibited excellent anti-T. gondii activity, inhibiting T. gondii invasion and proliferation in a dose-dependent manner, with an EC₅₀ of 14.05 ± 3.96 μg/mL. In the in vivo, licarin-B treatment significantly reduced the parasite burden in tissues compared to no treatment, protected the 90% infected mice from to death at 50 mg/kg.bw. Flow cytometry analysis suggested a significant reduction in T. gondii survival after licarin-B treatment. Ultrastructural changes in T. gondii were observed by transmission electron microscopy (TEM), as licarin-B induced mitochondrial swelling and formation of cytoplasmic vacuoles, an autophagosome-like double-membrane structure and extensive clefts around the T. gondii nucleus. Furthermore, MitoTracker Red CMXRos, MDC, and DAPI staining showed that licarin-B promoted mitochondrial damage, autophagosome formation, and nuclear disintegration, which were consistent with the TEM observations. Together, these findings indicate that licarin-B is a promising anti-T. gondii agent that potentially functions by damaging mitochondria and activating autophagy, leading to T. gondii death.

Resveratrol impacts in oxidative stress in liver during Trypanosoma cruzi infection

Trypanosoma cruzi is the causative agent of Chagas disease, infecting the heart, intestines and liver tissues. There is growing evidence that oxidative stress, defined as a persistent imbalance between highly oxidative compounds and antioxidant defenses, is a marker of tissue inflammation; it is related to immune responses such as damage, as well as to strand breaks in DNA contributing to disease progression. Antioxidant agents help mitigate the damage caused by inflammation, preventing or slowing damage to cells caused by free radicals. In this sense, resveratrol (RSV) is an important polyphenol that demonstrates antioxidant effects. It reverses damage caused by several infectious diseases. The aim of the present study was to determine whether treatment with RSV would prevent or minimize oxidative damage caused by T. cruzi. The animals were divided into four groups (n = 5): A) control; B) control + RSV; C) infected and D) infected + RSV. The infected groups received 1 x 10⁴ Y strain trypomastigotes via intraperitoneal injection; after confirmation of infection, the mice received RSV 100 mg/kg for seven days orally. On the 8th day post-infection, we collected liver tissue for analysis of oxidant/antioxidant status: superoxide dismutase (SOD), catalase (CAT), and glutathione s-transferase (GST) activities, as well as reactive oxygen species (ROS), non-protein thiols (NPSH), thiols, carbonyl protein, thiobarbituric acid reactive substance (TBARS), and finally, the nitrite/nitrate ratio (NOx) levels were determined. The administration of RSV did not exert direct effect on parasitemia. The infection produced high levels of TBARS, NOx, and ROS levels in liver tissue, suggesting cellular injury with production of free radicals in animals infected by T. cruzi. RSV positively modulated SOD and aumenting GST activities enzymes in infected animals. Protein thiols levels in infected animals were lower than those of control. Taken together, the data suggest T. cruzi causes hepatic oxidative stress, and RSV 100 mg/kg for seven days it's dosen't seem minimized these negative effects in the acute phase of disease.

Resveratrol induces H3 and H4K16 deacetylation and H2A.X phosphorylation in Toxoplasma gondii

Objective

Resveratrol (RSV) is a multitarget drug that has demonstrated activity against Toxoplasma gondii in macrophage and human foreskin fibroblast (HFF) cell line infection models. However, the mechanism of action of RSV has not yet been determined. Thus, with the aim of identifying a possible mechanism of the anti-T. gondii activity of this compound, we analyzed the effects of RSV on histones H3 and H4 lysine 16 acetylation (H4K16). We also analyzed RSV-induced DNA damage to intracellular tachyzoites by using the DNA damage marker phosphorylated histone H2A.X (γH2AX).

Results

RSV inhibited intracellular T. gondii tachyzoite growth at concentrations below the toxic threshold for host cells. The IC₅₀ value after 24 h of treatment was 53 μM. RSV induced a reduction in H4K16 acetylation (H4K16ac), a marker associated with transcription, DNA replication and homologous recombination repair. A similar deacetylation effect was observed on histone H3. RSV also increased T. gondii H2A.X phosphorylation at the SQE motif (termed γH2A.X), which is a DNA damage-associated posttranslational modification. Our findings suggest a possible link between RSV and DNA damage or repair processes that is possibly associated with DNA replication stress.

Evaluating the Antiparasitic Activity of Novel BPZ Derivatives Against Toxoplasma gondii

Prevalence studies revealed that one-third of the human population is chronically infected with Toxoplasma gondii. Presently, such infections are without medical treatment that effectively eradicates the parasite once it is in its latent form. Moreover, the therapeutics used to treat acute infections are poorly tolerated by patients and also cause the parasite to convert into long-lasting tissue cysts. Hence, there is a dire need for compounds with antiparasitic activity against all forms of T. gondii. This study examines the antiparasitic capacity of nine novel bisphenol Z (BPZ) derivatives to determine whether they possessed any activity that prevented T. gondii replication. To begin assessing the efficacy of the novel derivatives, parasites were treated with increasing concentrations of the compounds, then doubling assays and MitoTracker staining were performed. Three of the nine compounds demonstrated strong inhibitory activity, i.e., parasite replication significantly decreased with higher concentrations. Additionally, many of the treated parasites exhibited decreases in fluorescent signaling and disruption of mitochondrial morphology. These findings suggest that bisphenol Z compounds disrupt mitochondrial function to inhibit parasite replication and may provide a foundation for the development of new and effective treatment modalities against T. gondii.

Neuroprotective role of resveratrol mediated by purinergic signalling in cerebral cortex of mice infected by Toxoplasma gondii

The central nervous system of the intermediate host plays a central role in lifelong persistence of Toxoplasma gondii as well as the pathogenesis of congenital toxoplasmosis and reactivated infection in immunocompromised individuals. The purinergic system has been implicated in a wide range of immunological pathways for controlling intracellular responses to pathogens, including T. gondii. In the present study, we investigated the effect of resveratrol (RSV) on ectonucleotidases, adenosine deaminase (ADA), and purinergic receptors during chronic infection by T. gondii. For this study, Swiss mice were divided into control (CTL), resveratrol (RSV), infected (INF), and INF+RSV groups. The animals were orally infected with the VEG strain and treated with RSV (100 mg/kg, orally). Ectonucleotidase activities, P2X₇, P2Y₁, A1, and A_2A purinergic receptor density, ROS, and thiobarbituric acid reactive substances levels were measured in the cerebral cortex of mice. T. gondii infection increased NTPDase and reduced ADA activities. Treatment with RSV also affected enzymes hydrolysing extracellular nucleotides and nucleosides. Finally, RSV affected P1 and P2 purinergic receptor expression during T. gondii infection. Overall, RSV-mediated beneficial changes in purinergic signalling and oxidative stress, possibly improving cerebral cortex homeostasis in T. gondii infection.

Emerging Therapeutic Targets Against Toxoplasma gondii: Update on DNA Repair Response Inhibitors and Genotoxic Drugs

Toxoplasma gondii is the causative agent of toxoplasmosis in animals and humans. This infection is transmitted to humans through oocysts released in the feces of the felines into the environment or by ingestion of undercooked meat. This implies that toxoplasmosis is a zoonotic disease and T. gondii is a foodborne pathogen. In addition, chronic toxoplasmosis in goats and sheep is the cause of recurrent abortions with economic losses in the sector. It is also a health problem in pets such as cats and dogs. Although there are therapies against this infection in its acute stage, they are not able to permanently eliminate the parasite and sometimes they are not well tolerated. To develop better, safer drugs, we need to elucidate key aspects of the biology of T. gondii. In this review, we will discuss the importance of the homologous recombination repair (HRR) pathway in the parasite's lytic cycle and how components of these processes can be potential molecular targets for new drug development programs. In that sense, the effect of different DNA damage agents or HHR inhibitors on the growth and replication of T. gondii will be described. Multitarget drugs that were either associated with other targets or were part of general screenings are included in the list, providing a thorough revision of the drugs that can be tested in other scenarios.

Transcriptional changes in Toxoplasma gondii in response to treatment with monensin

Background

Infection with the apicomplexan protozoan parasite T. gondii can cause severe and potentially fatal cerebral and ocular disease, especially in immunocompromised individuals. The anticoccidial ionophore drug monensin has been shown to have anti-Toxoplasma gondii properties. However, the comprehensive molecular mechanisms that underlie the effect of monensin on T. gondii are still largely unknown. We hypothesized that analysis of T. gondii transcriptional changes induced by monensin treatment can reveal new aspects of the mechanism of action of monensin against T. gondii.

Methods

Porcine kidney (PK)-15 cells were infected with tachyzoites of T. gondii RH strain. Three hours post-infection, PK-15 cells were treated with 0.1 μM monensin, while control cells were treated with medium only. PK-15 cells containing intracellular tachyzoites were harvested at 6 and 24 h post-treatment, and the transcriptomic profiles of T. gondii-infected PK-15 cells were examined using high-throughput RNA sequencing (RNA-seq). Quantitative real-time PCR was used to verify the expression of 15 differentially expressed genes (DEGs) identified by RNA-seq analysis.

Results

A total of 4868 downregulated genes and three upregulated genes were identified in monensin-treated T. gondii, indicating that most of T. gondii genes were suppressed by monensin. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of T. gondii DEGs showed that T. gondii metabolic and cellular pathways were significantly downregulated. Spliceosome, ribosome, and protein processing in endoplasmic reticulum were the top three most significantly enriched pathways out of the 30 highly enriched pathways detected in T. gondii. This result suggests that monensin, via down-regulation of protein biosynthesis in T. gondii, can limit the parasite growth and proliferation.

Conclusions

Our findings provide a comprehensive insight into T. gondii genes and pathways with altered expression following monensin treatment. These data can be further explored to achieve better understanding of the specific mechanism of action of monensin against T. gondii.