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Life Science Alliance Jun 2024Increasing numbers of antimalarial compounds are being identified that converge mechanistically at inhibition of cytoplasmic translation, regardless of the molecular...
Increasing numbers of antimalarial compounds are being identified that converge mechanistically at inhibition of cytoplasmic translation, regardless of the molecular target or mechanism. A deeper understanding of how their effectiveness as liver stage translation inhibitors relates to their chemoprotective potential could prove useful. Here, we probed that relationship using the -HepG2 liver stage infection model. After determining translation inhibition ECs for five compounds, we tested them at equivalent effective concentrations to compare the parasite response to, and recovery from, a brief period of translation inhibition in early schizogony, followed by parasites to 120 h post-infection to assess antiplasmodial effects of the treatment. We show compound-specific heterogeneity in single parasite and population responses to translation inhibitor treatment, with no single metric strongly correlated to the release of hepatic merozoites for all compounds. We also demonstrate that DDD107498 is capable of exerting antiplasmodial effects on translationally arrested liver stage parasites and uncover unexpected growth dynamics during the liver stage. Our results demonstrate that translation inhibition efficacy does not determine antiplasmodial efficacy for these compounds.
Topics: Animals; Plasmodium berghei; Parasites; Antimalarials; Liver; Merozoites
PubMed: 38575357
DOI: 10.26508/lsa.202302540 -
Brain : a Journal of Neurology Feb 2024Cerebral malaria is the deadliest complication that can arise from Plasmodium infection. CD8 T-cell engagement of brain vasculature is a putative mechanism of...
Cerebral malaria is the deadliest complication that can arise from Plasmodium infection. CD8 T-cell engagement of brain vasculature is a putative mechanism of neuropathology in cerebral malaria. To define contributions of brain endothelial cell major histocompatibility complex (MHC) class I antigen-presentation to CD8 T cells in establishing cerebral malaria pathology, we developed novel H-2Kb LoxP and H-2Db LoxP mice crossed with Cdh5-Cre mice to achieve targeted deletion of discrete class I molecules, specifically from brain endothelium. This strategy allowed us to avoid off-target effects on iron homeostasis and class I-like molecules, which are known to perturb Plasmodium infection. This is the first endothelial-specific ablation of individual class-I molecules enabling us to interrogate these molecular interactions. In these studies, we interrogated human and mouse transcriptomics data to compare antigen presentation capacity during cerebral malaria. Using the Plasmodium berghei ANKA model of experimental cerebral malaria (ECM), we observed that H-2Kb and H-2Db class I molecules regulate distinct patterns of disease onset, CD8 T-cell infiltration, targeted cell death and regional blood-brain barrier disruption. Strikingly, ablation of either molecule from brain endothelial cells resulted in reduced CD8 T-cell activation, attenuated T-cell interaction with brain vasculature, lessened targeted cell death, preserved blood-brain barrier integrity and prevention of ECM and the death of the animal. We were able to show that these events were brain-specific through the use of parabiosis and created the novel technique of dual small animal MRI to simultaneously scan conjoined parabionts during infection. These data demonstrate that interactions of CD8 T cells with discrete MHC class I molecules on brain endothelium differentially regulate development of ECM neuropathology. Therefore, targeting MHC class I interactions therapeutically may hold potential for treatment of cases of severe malaria.
Topics: Mice; Humans; Animals; Malaria, Cerebral; Endothelial Cells; Brain; Blood-Brain Barrier; CD8-Positive T-Lymphocytes; Endothelium; Mice, Inbred C57BL; Disease Models, Animal
PubMed: 37776513
DOI: 10.1093/brain/awad319 -
Journal of Parasitology Research 2024Comorbidities that involve infectious and noninfectious diseases, such as malaria and cancer, have been described. Cancer and malaria induce changes in the nociceptive...
Comorbidities that involve infectious and noninfectious diseases, such as malaria and cancer, have been described. Cancer and malaria induce changes in the nociceptive and inflammatory responses through similar pathophysiological mechanisms. However, it is unclear whether malaria and antimalarial treatment can change the inflammatory and nociceptive responses induced by solid cancer. Therefore, the present study experimentally evaluated the effect of infection by strain ANKA and chloroquine treatment on the nociceptive and inflammatory responses induced by the solid Ehrlich tumor in male BALB/c mice. On the 1 experimental day, mice were infected with and injected with tumor cells in the left hind paw. From the 7 to the 9 experimental day, mice were treated daily with chloroquine. The parasitemia was evaluated on the 7 and 10 days after infection. On the 11 experimental day, mice were evaluated on the von Frey filament test, the hot plate test, and the paw volume test. At the end of the experimental tests on the 11th day, the peripheral blood of all mice was collected for dosing of IL-1 and TNF-. The blood parasitemia significantly increased from the 7 to the 10 day. The chloroquine treatment significantly decreased the parasitemia on the 10 day. The presence of the tumor did not significantly change the parasitemia on the 7 and 10 days in mice treated and nontreated with chloroquine. On the 11 day, the mechanical and thermal nociceptive responses significantly increased in mice with tumors. The treatment with antimalarial significantly reduced the mechanical nociceptive response induced by tumors. The hyperalgesia induced by tumors did not change with malaria. The mechanical and thermal hyperalgesia induced by the tumor was significantly reduced in mice treated and healed from malaria. On the 11 day, the volume of the paw injected by the tumor was significantly increased. The mice treated with chloroquine, infected with malaria, or healed of malaria showed reduced paw edema induced by the tumor. Mice with tumors did not show a change in IL- and TNF- serum levels. Mice with tumors showed a significant increase in serum levels of IL-1 but not TNF- when treated with chloroquine, infected with malaria, or healed of malaria. In conclusion, the results show that malaria infection and chloroquine treatment can influence, in synergic form, the nociceptive and inflammatory responses induced by the solid tumor. Moreover, the mechanical antinociception, the thermal hyperalgesia, and the antiedema effect observed in mice treated with chloroquine and healed from malaria can be related to the increase in the serum level of IL-1.
PubMed: 38774541
DOI: 10.1155/2024/3771926 -
One Health (Amsterdam, Netherlands) Dec 2023Ingestion of an additional blood meal(s) by a hematophagic insect can accelerate development of several vector-borne parasites and pathogens. Most studies, however,...
Ingestion of an additional blood meal(s) by a hematophagic insect can accelerate development of several vector-borne parasites and pathogens. Most studies, however, offer blood from the same vertebrate host species as the original challenge (for e.g., human for primary and additional blood meals). Here, we show a second blood meal from bovine and canine hosts can also enhance sporozoite migration in mosquitoes infected with the human- and rodent-restricted and respectively. The extrinsic incubation period (time to sporozoite appearance in salivary glands) showed more consistent reductions with blood from human and bovine donors than canine blood, although the latter's effect may be confounded by the toxicity, albeit non-specific, associated with the anticoagulant used to collect whole blood from donors. The complex patterns of enhancement highlight the limitations of a laboratory system but are nonetheless reminiscent of parasite host-specificity and mosquito adaptations, and the genetic predisposition of for bovine blood. We suggest that in natural settings, a blood meal from any vertebrate host could accentuate the risk of human infections by : targeting vectors that also feed on animals, via endectocides for instance, may reduce the number of malaria-infected mosquitoes and thus directly lower residual transmission. Since endectocides also benefit animal health, our results underscore the utility of the One Health framework, which postulates that human health and well-being is interconnected with that of animals. We posit this framework will be further validated if our observations also apply to other vector-borne diseases which together are responsible for some of the highest rates of morbidity and mortality in socio-economically disadvantaged populations.
PubMed: 38024285
DOI: 10.1016/j.onehlt.2023.100582 -
BioRxiv : the Preprint Server For... Aug 2023A novel cellular response of midgut progenitors (stem cells and enteroblasts) to infection was investigated in The presence of developing oocysts triggers...
A novel cellular response of midgut progenitors (stem cells and enteroblasts) to infection was investigated in The presence of developing oocysts triggers proliferation of midgut progenitors that is modulated by the Jak/STAT pathway, and proportional to the number of oocysts on individual midguts. The percentage of parasites in direct contact with enteroblasts increases over time, as progenitors proliferate. Enhancing proliferation of progenitors significantly decreases oocyst numbers, while limiting proliferation increases oocyst survival. Live imaging revealed that enteroblasts interact directly with oocysts and eliminate them. Midgut progenitors sense the presence of oocysts and mount a cellular defense response that involves extensive proliferation and tissue remodeling, followed by oocysts lysis and phagocytosis of parasite remnants by enteroblasts.
PubMed: 37577486
DOI: 10.1101/2023.08.02.551669 -
PLoS Pathogens Nov 2023Neuropilin-1 (Nrp-1) expression on CD8+ T cells has been identified in tumor-infiltrating lymphocytes and in persistent murine gamma-herpes virus infections, where it...
Neuropilin-1 (Nrp-1) expression on CD8+ T cells has been identified in tumor-infiltrating lymphocytes and in persistent murine gamma-herpes virus infections, where it interferes with the development of long-lived memory T cell responses. In parasitic and acute viral infections, the role of Nrp-1 expression on CD8+ T cells remains unclear. Here, we demonstrate a strong induction of Nrp-1 expression on CD8+ T cells in Plasmodium berghei ANKA (PbA)-infected mice that correlated with neurological deficits of experimental cerebral malaria (ECM). Likewise, the frequency of Nrp-1+CD8+ T cells was significantly elevated and correlated with liver damage in the acute phase of lymphocytic choriomeningitis virus (LCMV) infection. Transcriptomic and flow cytometric analyses revealed a highly activated phenotype of Nrp-1+CD8+ T cells from infected mice. Correspondingly, in vitro experiments showed rapid induction of Nrp-1 expression on CD8+ T cells after stimulation in conjunction with increased expression of activation-associated molecules. Strikingly, T cell-specific Nrp-1 ablation resulted in reduced numbers of activated T cells in the brain of PbA-infected mice as well as in spleen and liver of LCMV-infected mice and alleviated the severity of ECM and LCMV-induced liver pathology. Mechanistically, we identified reduced blood-brain barrier leakage associated with reduced parasite sequestration in the brain of PbA-infected mice with T cell-specific Nrp-1 deficiency. In conclusion, Nrp-1 expression on CD8+ T cells represents a very early activation marker that exacerbates deleterious CD8+ T cell responses during both, parasitic PbA and acute LCMV infections.
Topics: Mice; Animals; Neuropilin-1; Parasites; Malaria, Cerebral; Lymphocytic Choriomeningitis; Lymphocytic choriomeningitis virus; CD8-Positive T-Lymphocytes; Mice, Inbred C57BL
PubMed: 38019895
DOI: 10.1371/journal.ppat.1011837 -
Journal of Neuroinflammation May 2024Cerebral malaria (CM) is the most lethal complication of malaria, and survivors usually endure neurological sequelae. Notably, the cytotoxic effect of infiltrating...
BACKGROUND
Cerebral malaria (CM) is the most lethal complication of malaria, and survivors usually endure neurological sequelae. Notably, the cytotoxic effect of infiltrating Plasmodium-activated CD8 T cells on cerebral microvasculature endothelial cells is a prominent feature of the experimental CM (ECM) model with blood-brain barrier disruption. However, the damage effect of CD8 T cells infiltrating the brain parenchyma on neurons remains unclear. Based on the immunosuppressive effect of the PD-1/PD-L1 pathway on T cells, our previous study demonstrated that the systemic upregulation of PD-L1 to inhibit CD8 T cell function could effectively alleviate the symptoms of ECM mice. However, it has not been reported whether neurons can suppress the pathogenic effect of CD8 T cells through the PD-1/PD-L1 negative immunomodulatory pathway. As the important inflammatory factor of CM, interferons can induce the expression of PD-L1 via different molecular mechanisms according to the neuro-immune microenvironment. Therefore, this study aimed to investigate the direct interaction between CD8 T cells and neurons, as well as the mechanism of neurons to alleviate the pathogenic effect of CD8 T cells through up-regulating PD-L1 induced by IFNs.
METHODS
Using the ECM model of C57BL/6J mice infected with Plasmodium berghei ANKA (PbA), morphological observations were conducted in vivo by electron microscope and IF staining. The interaction between the ECM CD8 T cells (immune magnetic bead sorting from spleen of ECM mice) and primary cultured cortical neurons in vitro was observed by IF staining and time-lapse photography. RNA-seq was performed to analyze the signaling pathway of PD-L1 upregulation in neurons induced by IFNβ or IFNγ, and verified through q-PCR, WB, IF staining, and flow cytometry both in vitro and in vivo using IFNAR or IFNGR gene knockout mice. The protective effect of adenovirus-mediated PD-L1 IgGFc fusion protein expression was verified in ECM mice with brain stereotaxic injection in vivo and in primary cultured neurons via viral infection in vitro.
RESULTS
In vivo, ECM mice showed infiltration of activated CD8 T cells and neuronal injury in the brain parenchyma. In vitro, ECM CD8 T cells were in direct contact with neurons and induced axonal damage, as an active behavior. The PD-L1 protein level was elevated in neurons of ECM mice and in primary cultured neurons induced by IFNβ, IFNγ, or ECM CD8 T cells in vitro. Furthermore, the IFNβ or IFNγ induced neuronal expression of PD-L1 was mediated by increasing STAT1/IRF1 pathway via IFN receptors. The increase of PD-L1 expression in neurons during PbA infection was weakened after deleting the IFNAR or IFNGR. Increased PD-L1 expression by adenovirus partially protected neurons from CD8 T cell-mediated damage both in vitro and in vivo.
CONCLUSION
Our study demonstrates that both type I and type II IFNs can induce neurons to upregulate PD-L1 via the STAT1/IRF1 pathway mediated by IFN receptors to protect against activated CD8 T cell-mediated damage, providing a targeted pathway to alleviate neuroinflammation during ECM.
Topics: Animals; Mice; B7-H1 Antigen; CD8-Positive T-Lymphocytes; Interferon Regulatory Factor-1; Interferon-gamma; Malaria, Cerebral; Mice, Inbred C57BL; Mice, Knockout; Neurons; Plasmodium berghei; Signal Transduction; STAT1 Transcription Factor; Up-Regulation
PubMed: 38715061
DOI: 10.1186/s12974-024-03114-7 -
Molecules (Basel, Switzerland) Jul 2023From , naphthoquinones, isoeleutherine, and eleutherol were isolated, and previous studies have reported the antioxidant activity of these metabolites. The present work...
From , naphthoquinones, isoeleutherine, and eleutherol were isolated, and previous studies have reported the antioxidant activity of these metabolites. The present work evaluated the role of oxidative changes in mice infected with Plasmodium berghei and treated with extract, fraction, and isolated compounds, as well as to verify possible oxidative changes induced by these treatments. extracts were prepared from powder from the bulbs, which were submitted to maceration with ethanol, yielding the extract (EEEp), which was fractionated under reflux, and the dichloromethane fraction (FDMEp) was submitted for further fractionation, leading to the isolation of isoeleutherine, eleutherine, and eleutherol. The antimalarial activity was examined using the suppressive test, evaluating the following parameters of oxidative stress: trolox equivalent antioxidant capacity (TEAC), thiobarbituric acid reactive substances (TBARS), and reduced glutathione (GSH). Furthermore, the molecular docking of naphthoquinones, eleutherol, eleutherine, and isoeleutherine interactions with antioxidant defense enzymes was investigated, which was favorable for the formation of the receptor-ligand complex, according to the re-rank score values. Eleutherine and isoeleutherine are the ones with the lowest binding energy for catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx1), showing themselves as possible targets of these molecules in the involvement of redox balance. Data from the present study showed that treatments with stimulated an increase in antioxidant capacity and a reduction in oxidative stress in mice infected with , with naphthoquinones being responsible for reducing oxidative changes and disease severity.
Topics: Mice; Animals; Antioxidants; Molecular Docking Simulation; Oxidative Stress; Naphthoquinones; Catalase; Plant Extracts; Glutathione; Glutathione Peroxidase; Thiobarbituric Acid Reactive Substances; Superoxide Dismutase
PubMed: 37513429
DOI: 10.3390/molecules28145557 -
International Journal of Molecular... Jul 2023Newly emerging data suggest that several neutrophil defense mechanisms may play a role in both aggravating and protecting against malaria. These exciting findings...
Newly emerging data suggest that several neutrophil defense mechanisms may play a role in both aggravating and protecting against malaria. These exciting findings suggest that the balance of these cells in the host body may have an impact on the pathogenesis of malaria. To fully understand the role of neutrophils in severe forms of malaria, such as cerebral malaria (CM), it is critical to gain a comprehensive understanding of their behavior and functions. This study investigated the dynamics of neutrophil and T cell responses in C57BL/6 and BALB/c mice infected with ANKA, murine models of experimental cerebral malaria (ECM) and non-cerebral experimental malaria, respectively. The results demonstrated an increase in neutrophil percentage and neutrophil-T cell ratios in the spleen and blood before the development of clinical signs of ECM, which is a phenomenon not observed in the non-susceptible model of cerebral malaria. Furthermore, despite the development of distinct forms of malaria in the two strains of infected animals, parasitemia levels showed equivalent increases throughout the infection period evaluated. These findings suggest that the neutrophil percentage and neutrophil-T cell ratios may be valuable predictive tools for assessing the dynamics and composition of immune responses involved in the determinism of ECM development, thus contributing to the advancing of our understanding of its pathogenesis.
Topics: Animals; Mice; Malaria, Cerebral; Neutrophils; Mice, Inbred C57BL; Plasmodium berghei; CD8-Positive T-Lymphocytes; Disease Models, Animal
PubMed: 37511092
DOI: 10.3390/ijms241411332 -
Pharmaceutics Oct 2023Malaria is a parasitic infection responsible for high morbidity and mortality rates worldwide. During the disease, phagocytosis of infected red blood cells by the...
Malaria is a parasitic infection responsible for high morbidity and mortality rates worldwide. During the disease, phagocytosis of infected red blood cells by the macrophages induces the production of reactive oxygen (ROS) and nitrogen species (RNS), culminating in parasite death. Curcumin (CUR) is a bioactive compound that has been demonstrated to reduce the production of pro-inflammatory cytokines and chemokines produced by macrophages but to reduce parasitemia in infected mice. Hence, the main purpose of this study is to investigate whether curcumin may interfere with macrophage function and polarization after infection in vitro. In our findings, non-polarized macrophage (M0), classically activated (M1), and alternatively activated (M2) phenotypes showed significantly increased phagocytosis of infected red blood cells (iRBCs) when compared to phagocytosis of uninfected red blood cells (RBCs) 3 h after infection. After 24 h, M1 macrophages exposed to RBCs + CUR showed greater elimination capacity when compared to macrophages exposed to iRBCs + CUR, suggesting the interference of curcumin with the microbicidal activity. Additionally, curcumin increased the phagocytic activity of macrophages when used in non-inflammatory conditions (M0) and reduced the inducible nitric oxide synthase (iNOS) and arginase activities in all macrophage phenotypes infected (M0, M1, and M2), suggesting interference in arginine availability by curcumin and balance promotion in macrophage polarization in neutral phenotype (M0). These results support the view of curcumin treatment in malaria as an adjuvant, promoting a balance between pro- and anti-inflammatory responses for a better clinical outcome.
PubMed: 37896265
DOI: 10.3390/pharmaceutics15102505