RESUMO
Introduction: Toxoplasma gondii, responsible for causing toxoplasmosis, is a prevalent food and waterborne pathogen worldwide. It commonly infects warm-blooded animals and affects more than a third of the global human population. Once ingested, the parasite enters the host's small intestine and rapidly disseminates throughout the body via the bloodstream, infiltrating various tissues. Leukocyte-driven responses are vital against T. gondii, with neutrophils playing a dual role: swiftly recruited to infection sites, releasing inflammatory mediators, and serving as a replication hub and Trojan horses, aiding parasite spread. Neutrophils from various hosts release extracellular traps (NETs) against the protozoan. However, gaps persist regarding the mechanisms of NETs production to parasite and their significance in infection control. This study investigates the interplay between human neutrophils and T. gondii, exploring dynamics, key molecules, and signaling pathways involved in NETs production upon protozoan challenge. Methods and Results: Using confocal and electron microscopy, live cell imaging, pharmacological inhibitors, and DNA quantification assays, we find that human neutrophils promptly release both classical and rapid NETs upon pathogen stimulation. The NETs structure exhibits diverse phenotypes over time and is consistently associated with microorganisms. Mechanisms involve neutrophil elastase and peptidylarginine deiminase, along with intracellular calcium signaling and the PI3K pathway. Unexpectedly, human traps do not diminish viability or infectivity, but potentially aid in capturing parasites for subsequent neutrophil phagocytosis and elimination. Discussion: By revealing NETs formation mechanisms and their nuanced impact on T. gondii infection dynamics, our findings contribute to broader insights into host-pathogen relationships.
Assuntos
Armadilhas Extracelulares , Toxoplasma , Toxoplasmose , Animais , Humanos , Armadilhas Extracelulares/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Toxoplasmose/metabolismo , Neutrófilos/metabolismo , Toxoplasma/fisiologiaRESUMO
The interaction of Toxoplasma gondii with the gastrointestinal tract of its host is highly regulated. Once ingested, the parasite crosses the epithelium without altering the permeability of the intestinal barrier. Nevertheless, many studies report alterations ranging from structural to functional damage in cells and tissues that make up the wall of the small and large intestine. Although the immune response to the parasite has been extensively studied, the role of serotonin (5-HT) in toxoplasmosis is poorly understood. Here we investigate the distribution of cells expressing 5-HT and its effects on cells and tissues of the jejunal wall of rats after 2, 3, or 7 days of T. gondii infection. KEY RESULTS: Our results show that transposition of the jejunal epithelium by T. gondii leads to ruptures in the basement membrane and activation of the immune system, as confirmed by the decrease in laminin immunostaining and the increase in the number of mast cells, respectively. CONCLUSIONS AND INFERENCES: We showed an increase in the number of enterochromaffin cells and mast cells expressing 5-HT in the jejunal wall. We also observed that the percentage of serotonergic mast cells increased in the total population. Thus, we can suggest that oral infection by T. gondii oocysts preferentially activates non-neuronal cells expressing 5-HT. Together, these results may explain both the changes in the extracellular matrix and the morphology of the enteric ganglia.
Assuntos
Células Enterocromafins , Jejuno , Oocistos/metabolismo , Serotonina/biossíntese , Toxoplasma/metabolismo , Toxoplasmose/metabolismo , Doença Aguda , Animais , Células Enterocromafins/metabolismo , Células Enterocromafins/parasitologia , Jejuno/metabolismo , Jejuno/parasitologia , Masculino , Ratos , Ratos WistarRESUMO
Leydig cells play pivotal roles in eliciting male characteristics by producing testosterone and any damage to these cells can compromise male fertility Toxoplasma gondii (T. gondii) is an intracellular parasite capable to invade any nucleated cell, including cells from male reproductive system. Herein, we evaluated the capacity of RH strain of T. gondii to infect TM3 Leydig cells and the impact of this infection on testosterone and inflammatory mediators production. We first, by performing adherence, infection, and intracellular proliferation assays, we found a significant increase in the number of infected Leydig cells, peaking 48 h after the infection with T. gondii. Supernatants of TM3 infected cells exhibited, in a time-dependent manner, increased levels of testosterone as well as monocyte chemoattractant protein-1 (MCP-1) and interferon-γ (IFN-γ), which is correlated with the robust T. gondii infection. In conclusion, our study provides new insights regarding the harmful effects of T. gondii infection on male reproductive system.
Assuntos
Células Intersticiais do Testículo/parasitologia , Testosterona/biossíntese , Toxoplasmose/metabolismo , Animais , Quimiocina CCL2/biossíntese , Interferon gama/biossíntese , Masculino , Camundongos Endogâmicos BALB C , Fatores de Tempo , ToxoplasmaRESUMO
The protozoan parasite Toxoplasma gondii modulates host cell responses to favor its success in the early stage of infections by secreting proteins from its apical organelles. Some of these proteins, including microneme proteins (MICs) 1 and 4, trigger pro-inflammatory host cell responses. The lectins MIC1 and MIC4 interact with N-linked glycans on TLR2 and TLR4, activating NF-κB and producing IL-12, TNF-α, and IL-6. Interestingly, MIC1 and MIC4 also trigger secretion of the anti-inflammatory cytokine IL-10 through mechanisms as yet unknown. Herein, we show that the ability of these MICs to induce macrophages to produce IL-10 depends on TLR4 internalization from the cell surface. Macrophages subjected to blockade of endocytosis by Dynasore continued to release TNF-α, but failed to produce IL-10, in response to MIC1 or MIC4 exposure. Similarly, IL-10 was not produced by Dynasore-conditioned T. gondii-infected macrophages. Furthermore, MIC1- or MIC4-stimulated macrophages gained transient tolerance to LPS. We report a previously undiscovered mechanism by which well-defined T. gondii components inhibit a host inflammatory response.
Assuntos
Moléculas de Adesão Celular/imunologia , Interleucina-10/biossíntese , Macrófagos/imunologia , Macrófagos/metabolismo , Proteínas de Protozoários/imunologia , Receptor 4 Toll-Like/metabolismo , Toxoplasma/imunologia , Toxoplasmose/imunologia , Toxoplasmose/metabolismo , Animais , Modelos Animais de Doenças , Endocitose , Endossomos/metabolismo , Humanos , Fator Regulador 3 de Interferon/metabolismo , Camundongos , Modelos Biológicos , Fosforilação , Ligação Proteica , Toxoplasmose/parasitologiaRESUMO
BACKGROUND: Behavioral and neurochemical alterations associated with toxoplasmosis may be influenced by the persistence of tissue cysts and activation of an immune response in the brain of Toxoplasma gondii-infected hosts. The cerebral extracellular matrix is organised as perineuronal nets (PNNs) that are both released and ensheath by some neurons and glial cells. There is evidences to suggest that PNNs impairment is a pathophysiological mechanism associated with neuropsychiatric conditions. However, there is a lack of information regarding the impact of parasitic infections on the PNNs integrity and how this could affect the host's behavior. OBJECTIVES: In this context, we aimed to analyse the impact of T. gondii infection on cyst burden, PNNs integrity, and possible effects in the locomotor activity of chronically infected mice. METHODS: We infected mice with T. gondii ME-49 strain. After thirty days, we assessed locomotor performance of animals using the open field test, followed by evaluation of cysts burden and PNNs integrity in four brain regions (primary and secondary motor cortices, prefrontal and somesthetic cortex) to assess the PNNs integrity using Wisteria floribunda agglutinin (WFA) labeling by immunohistochemical analyses. FINDINGS AND MAIN CONCLUSIONS: Our findings revealed a random distribution of cysts in the brain, the disruption of PNNs surrounding neurons in four areas of the cerebral cortex and hyperlocomotor behavior in T. gondii-infected mice. These results can contribute to elucidate the link toxoplasmosis with the establishment of neuroinflammatory response in neuropsychiatric disorders and to raise a discussion about the mechanisms related to changes in brain connectivity, with possible behavioral repercussions during chronic T. gondii infection.
Assuntos
Cerebelo/metabolismo , Matriz Extracelular/metabolismo , Neurônios Motores/citologia , Neurônios/patologia , Toxoplasmose Animal , Toxoplasmose/patologia , Animais , Cerebelo/citologia , Modelos Animais de Doenças , Camundongos , Neurônios Motores/metabolismo , Neurônios/metabolismo , Toxoplasma , Toxoplasmose/metabolismoRESUMO
Congenital abnormalities cause serious fetal consequences. The term TORCH is used to designate the most common perinatal infections, where: (T) refers to toxoplasmosis, (O) means "others" and includes syphilis, varicella-zoster, parvovirus B19, zika virus (ZIKV), and malaria among others, (R) refers to rubella, (C) relates to cytomegalovirus infection, and (H) to herpes simplex virus infections. Among the main abnormalities identified in neonates exposed to congenital infections are central nervous system (CNS) damage, microcephaly, hearing loss, and ophthalmological impairment, all requiring regular follow-up to monitor its progression. Protein changes such as mutations, post-translational modifications, abundance, structure, and function may indicate a pathological condition before the onset of the first symptoms, allowing early diagnosis and understanding of a particular disease or infection. The term "proteomics" is defined as the science that studies the proteome, which consists of the total protein content of a cell, tissue or organism in a given space and time, including post-translational modifications (PTMs) and interactions between proteins. Currently, quantitative bottom-up proteomic strategies allow rapid and high throughput characterization of complex biological mixtures. Investigating proteome modulation during host-pathogen interaction helps in elucidating the mechanisms of infection and in predicting disease progression. This "molecular battle" between host and pathogen is a key to identify drug targets and diagnostic markers. Here, we conducted a survey on proteomic techniques applied to congenital diseases classified in the terminology "TORCH", including toxoplasmosis, ZIKV, malaria, syphilis, human immunodeficiency virus (HIV), herpes simplex virus (HSV) and human cytomegalovirus (HCVM). We have highlighted proteins and/or protein complexes actively involved in the infection. Most of the proteomic studies reported have been performed in cell line models, and the evaluation of tissues (brain, muscle, and placenta) and biofluids (plasma, serum and urine) in animal models is still underexplored. Moreover, there are a plethora of studies focusing on the pathogen or the host without considering the triad mother-fetus-pathogen as a dynamic and interconnected system.
Assuntos
Transmissão Vertical de Doenças Infecciosas , Complicações Infecciosas na Gravidez/metabolismo , Proteômica/métodos , Feminino , Humanos , Gravidez , Sífilis/metabolismo , Sífilis/transmissão , Toxoplasmose/metabolismo , Toxoplasmose/transmissão , Viroses/metabolismo , Viroses/transmissãoRESUMO
INTRODUCTION: The intestinal microbiota plays an important role in modulating host immune responses. Oral Toxoplasma gondii infection can promote intestinal inflammation in certain mice strains. The IDO-AhR axis may control tryptophan (Trp) metabolism constituting an important immune regulatory mechanism in inflammatory settings. AIMS: In the present study, we investigated the role of the intestinal microbiota on Trp metabolism during oral infection with T gondii. METHODS AND RESULTS: Mice were treated with antibiotics for four weeks and then infected with T gondii by gavage. Histopathology and immune responses were evaluated 8 days after infection. We found that depletion of intestinal microbiota by antibiotics contributed to resistance against T gondii infection and led to reduced expression of AhR on dendritic and Treg cells. Mice depleted of Gram-negative bacteria presented higher levels of systemic Trp, downregulation of AhR expression and increased resistance to infection whereas depletion of Gram-positive bacteria did not affect susceptibility or expression of AhR on immune cells. CONCLUSION: Our findings indicate that the intestinal microbiota can control Trp availability and provide a link between the AhR pathway and host-microbiota interaction in acute infection with T gondii.
Assuntos
Microbioma Gastrointestinal/fisiologia , Toxoplasmose/metabolismo , Triptofano/metabolismo , Animais , Feminino , Inflamação/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Toxoplasma/imunologia , Toxoplasmose/imunologiaRESUMO
Recent advances in chronic toxoplasmosis understanding became the focus of discussion about behavioral abnormalities, which could be explained by cyst location and neuronal impairment in specific brain areas. Perineuronal nets (PNNs) are specialized extracellular matrices that surround the neuronal body and proximal dendrites and play key roles in neuronal circuitry maintenance and stabilization. Its impairment can lead to abnormal synaptic functioning with behavioral repercussions. In this context, we analyzed the impact of Toxoplasma gondii infection on neuronal integrity in the Corpus striatum of chronically infected mice. C57BL/6 and Balb/c female mice were infected with T. gondii ME49 cysts. Brain sections were submitted to immunohistochemistry with Wisteria floribunda agglutinin (WFA) for PNN labeling followed by quantification of tissue cyst and labeled neuronal cells 30 days after infection. Our results revealed that C57BL/6 exhibited a significant decrease in PNN-positive (WFA+) labeled neurons and an expressively higher number of tissue cysts than Balb/c mice. It was also possible to observe that the number of T. gondii tissue cysts and the number of WFA+ neurons were inversely correlated for C57BL/6-infected mice. However, no correlation was observed for Balb/c mice. These data suggest how the impact of parasite dissemination in the brain and host characteristics can influence neuronal integrity impairment during infection by decreasing WFA+ neurons. This might be a plausible pathway in which the presence of T. gondii contributes to behavioral changes in the infected host.
Assuntos
Corpo Estriado/patologia , Neurônios/patologia , Toxoplasmose/patologia , Animais , Doença Crônica , Matriz Extracelular/patologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Lectinas de Plantas , Receptores de N-Acetilglucosamina , Toxoplasma , Toxoplasmose/metabolismoRESUMO
BACKGROUND Behavioral and neurochemical alterations associated with toxoplasmosis may be influenced by the persistence of tissue cysts and activation of an immune response in the brain of Toxoplasma gondii-infected hosts. The cerebral extracellular matrix is organised as perineuronal nets (PNNs) that are both released and ensheath by some neurons and glial cells. There is evidences to suggest that PNNs impairment is a pathophysiological mechanism associated with neuropsychiatric conditions. However, there is a lack of information regarding the impact of parasitic infections on the PNNs integrity and how this could affect the host's behavior. OBJECTIVES In this context, we aimed to analyse the impact of T. gondii infection on cyst burden, PNNs integrity, and possible effects in the locomotor activity of chronically infected mice. METHODS We infected mice with T. gondii ME-49 strain. After thirty days, we assessed locomotor performance of animals using the open field test, followed by evaluation of cysts burden and PNNs integrity in four brain regions (primary and secondary motor cortices, prefrontal and somesthetic cortex) to assess the PNNs integrity using Wisteria floribunda agglutinin (WFA) labeling by immunohistochemical analyses. FINDINGS AND MAIN CONCLUSIONS Our findings revealed a random distribution of cysts in the brain, the disruption of PNNs surrounding neurons in four areas of the cerebral cortex and hyperlocomotor behavior in T. gondii-infected mice. These results can contribute to elucidate the link toxoplasmosis with the establishment of neuroinflammatory response in neuropsychiatric disorders and to raise a discussion about the mechanisms related to changes in brain connectivity, with possible behavioral repercussions during chronic T. gondii infection.
Assuntos
Animais , Camundongos , Cerebelo/metabolismo , Toxoplasmose/patologia , Toxoplasmose Animal , Matriz Extracelular/metabolismo , Neurônios Motores/citologia , Neurônios/patologia , Toxoplasma , Cerebelo/citologia , Toxoplasmose/metabolismo , Modelos Animais de Doenças , Neurônios Motores/metabolismo , Neurônios/metabolismoRESUMO
Toxoplasma gondii is the causative agent of toxoplasmosis, a parasitic disease with a wide global prevalence. The parasite forms cysts in skeletal muscle cells and neurons, although no evident association with inflammatory infiltrates has been typically found. We studied the impact of T. gondii infection on the myogenic program of mouse skeletal muscle cells (SkMC). The C2C12 murine myoblast cell line was infected with T. gondii tachyzoites (ME49 strain) for 24 h followed by myogenic differentiation induction. T. gondii infection caused a general decrease in myotube differentiation, fusion and maturation, along with decreased expression of myosin heavy chain. The expression of Myogenic Regulatory Factors Myf5, MyoD, Mrf4 and myogenin was modulated by the infection. Infected cultures presented increased proliferation rates, as assessed by Ki67 immunostaining, whereas neither host cell lysis nor apoptosis were significantly augmented in infected dishes. Cytokine Bead Array indicated that IL-6 and MCP-1 were highly increased in the medium from infected cultures, whereas TGF-ß1 was consistently decreased. Inhibition of the IL-6 receptor or supplementation with recombinant TGF-ß failed to reverse the deleterious effects caused by the infection. However, conditioned medium from infected cultures inhibited myogenesis in C2C12 cells. Activation of the Wnt/ß-catenin pathway was impaired in T. gondii-infected cultures. Our data indicate that T. gondii leads SkMCs to a pro-inflammatory phenotype, leaving cells unresponsive to ß-catenin activation, and inhibition of the myogenic differentiation program. Such deregulation may suggest muscle atrophy and molecular mechanisms similar to those involved in myositis observed in human patients.