Insights into the molecular basis of host behaviour manipulation by Toxoplasma gondii infection

2017 ◽  
Vol 1 (6) ◽  
pp. 563-572 ◽  
Author(s):  
Pierre-Mehdi Hammoudi ◽  
Dominique Soldati-Favre
Keyword(s):  
Toxoplasma Gondii ◽  
Stress Responses ◽  
Molecular Mechanisms ◽  
Brain Regions ◽  
Intermediate Hosts ◽  
Toxoplasma Gondii Infection ◽  
Host Parasite ◽  
Host Behaviour ◽  
The Brain ◽  
Brain Homeostasis

Typically illustrating the ‘manipulation hypothesis’, Toxoplasma gondii is widely known to trigger sustainable behavioural changes during chronic infection of intermediate hosts to enhance transmission to its feline definitive hosts, ensuring survival and dissemination. During the chronic stage of infection in rodents, a variety of neurological dysfunctions have been unravelled and correlated with the loss of cat fear, among other phenotypic impacts. However, the underlying neurological alteration(s) driving these behavioural modifications is only partially understood, which makes it difficult to draw more than a correlation between T. gondii infection and changes in brain homeostasis. Moreover, it is barely known which among the brain regions governing fear and stress responses are preferentially affected during T. gondii infection. Studies aiming at an in-depth dissection of underlying molecular mechanisms occurring at the host and parasite levels will be discussed in this review. Addressing this reminiscent topic in the light of recent technical progress and new discoveries regarding fear response, olfaction and neuromodulator mechanisms could contribute to a better understanding of this complex host–parasite interaction.

scholarly journals Behavioral biology of Toxoplasma gondii infection

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Wen Han Tong ◽  
Chris Pavey ◽  
Ryan O’Handley ◽  
Ajai Vyas
Keyword(s):  
Life Cycle ◽  
Toxoplasma Gondii ◽  
Protozoan Parasite ◽  
Research Area ◽  
Complex Life Cycle ◽  
Future Research ◽  
Intermediate Hosts ◽  
Laboratory Rodents ◽  
Toxoplasma Gondii Infection ◽  
Host Parasite

AbstractToxoplasma gondii is a protozoan parasite with a complex life cycle and a cosmopolitan host range. The asexual part of its life cycle can be perpetually sustained in a variety of intermediate hosts through a combination of carnivory and vertical transmission. However, T. gondii produces gametes only in felids after the predation of infected intermediate hosts. The parasite changes the behavior of its intermediate hosts by reducing their innate fear to cat odors and thereby plausibly increasing the probability that the definitive host will devour the infected host. Here, we provide a short description of such parasitic behavioral manipulation in laboratory rodents infected with T. gondii, along with a bird’s eye view of underpinning biological changes in the host. We also summarize critical gaps and opportunities for future research in this exciting research area with broad implications in the transdisciplinary study of host–parasite relationships.

scholarly journals Developmental cannabidiol exposure increases anxiety and modifies genome-wide brain DNA methylation in adult female mice

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Nicole M. Wanner ◽  
Mathia Colwell ◽  
Chelsea Drown ◽  
Christopher Faulk
Keyword(s):  
Dna Methylation ◽  
Molecular Mechanisms ◽  
Coat Color ◽  
Brain Regions ◽  
Functional Enrichment ◽  
Positive Effects ◽  
Genome Wide ◽  
Nulliparous Female ◽  
The Impact ◽  
The Brain

Abstract Background Use of cannabidiol (CBD), the primary non-psychoactive compound found in cannabis, has recently risen dramatically, while relatively little is known about the underlying molecular mechanisms of its effects. Previous work indicates that direct CBD exposure strongly impacts the brain, with anxiolytic, antidepressant, antipsychotic, and other effects being observed in animal and human studies. The epigenome, particularly DNA methylation, is responsive to environmental input and can direct persistent patterns of gene regulation impacting phenotype. Epigenetic perturbation is particularly impactful during embryogenesis, when exogenous exposures can disrupt critical resetting of epigenetic marks and impart phenotypic effects lasting into adulthood. The impact of prenatal CBD exposure has not been evaluated; however, studies using the psychomimetic cannabinoid Δ9-tetrahydrocannabinol (THC) have identified detrimental effects on psychological outcomes in developmentally exposed adult offspring. We hypothesized that developmental CBD exposure would have similar negative effects on behavior mediated in part by the epigenome. Nulliparous female wild-type Agouti viable yellow (Avy) mice were exposed to 20 mg/kg CBD or vehicle daily from two weeks prior to mating through gestation and lactation. Coat color shifts, a readout of DNA methylation at the Agouti locus in this strain, were measured in F1 Avy/a offspring. Young adult F1 a/a offspring were then subjected to tests of working spatial memory and anxiety/compulsive behavior. Reduced-representation bisulfite sequencing was performed on both F0 and F1 cerebral cortex and F1 hippocampus to identify genome-wide changes in DNA methylation for direct and developmental exposure, respectively. Results F1 offspring exposed to CBD during development exhibited increased anxiety and improved memory behavior in a sex-specific manner. Further, while no significant coat color shift was observed in Avy/a offspring, thousands of differentially methylated loci (DMLs) were identified in both brain regions with functional enrichment for neurogenesis, substance use phenotypes, and other psychologically relevant terms. Conclusions These findings demonstrate for the first time that despite positive effects of direct exposure, developmental CBD is associated with mixed behavioral outcomes and perturbation of the brain epigenome.

scholarly journals Transcriptomic analysis of frontotemporal lobar degeneration with TDP-43 pathology reveals cellular alterations across multiple brain regions

2021 ◽  
Author(s):  
Rahat Hasan ◽  
Jack Humphrey ◽  
Conceicao Bettencourt ◽  
Tammaryn Lashley ◽  
Pietro Fratta ◽  
...  
Keyword(s):  
Gene Expression ◽  
Frontotemporal Lobar Degeneration ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Temporal Cortex ◽  
Neuronal Loss ◽  
Underlying Disease ◽  
Brain Regions ◽  
Neuronal Markers ◽  
The Brain

Frontotemporal lobar degeneration (FTLD) is a group of heterogeneous neurodegenerative disorders affecting the frontal and temporal lobes of the brain. Nuclear loss and cytoplasmic aggregation of the RNA-binding protein TDP-43 represents the major FTLD pathology, known as FTLD-TDP. To date, there is no effective treatment for FTLD-TDP due to an incomplete understanding of the molecular mechanisms underlying disease development. Here we compared post-mortem tissue RNA-seq transcriptomes from the frontal cortex, temporal cortex and cerebellum between 28 controls and 30 FTLD-TDP patients to profile changes in cell-type composition, gene expression and transcript usage. We observed downregulation of neuronal markers in all three regions of the brain, accompanied by upregulation of microglia, astrocytes, and oligodendrocytes, as well as endothelial cells and pericytes, suggesting shifts in both immune activation and within the vasculature. We validate our estimates of neuronal loss using neuropathological atrophy scores and show that neuronal loss in the cortex can be mainly attributed to excitatory neurons, and that increases in microglial and endothelial cell expression are highly correlated with neuronal loss. All our analyses identified a strong involvement of the cerebellum in the neurodegenerative process of FTLD-TDP. Altogether, our data provides a detailed landscape of gene expression alterations to help unravel relevant disease mechanisms in FTLD.

Tissue cyst tropism in Toxoplasma gondii: a comparison of tissue cyst formation in organs of cats, and rodents fed oocysts

Parasitology ◽  
1997 ◽  
Vol 115 (1) ◽  
pp. 15-20 ◽  
Author(s):  
J. P. DUBEY
Keyword(s):  
Toxoplasma Gondii ◽  
Cyst Formation ◽  
Tissue Cyst ◽  
Intermediate Hosts ◽  
Mesenteric Lymph Nodes ◽  
Marked Contrast ◽  
Mesenteric Lymph ◽  
Time Period ◽  
Rats And Mice ◽  
The Brain

The persistence of Toxoplasma gondii tissue cysts in organs of cats (definitive host) and rodents (intermediate hosts) was studied. Nine cats, 12 rats, and 12 mice were fed T. gondii oocysts and their organs were digested in pepsin and then bioassayed for bradyzoites in mice. Of 9 cats killed 37 or 51 days after feeding 102 (2 cats), 103 (3 cats) or 104 (4 cats) oocysts of the VEG strain, tissue cysts were found in each cat; in the tongue of 9, in the heart of 5, in the brain of 4, and in the eyes of 1 cat. The dose had no effect on the distribution of tissue cysts in cats. Twelve rats were each fed 105 oocysts of the VEG strain of T. gondii and killed 21, 29, 64 or 237 days later. At each time-period, 11 tissues of 3 rats were pooled and bioassayed in mice. Tissue cysts were found in the brain, skeletal muscle, heart and kidneys of rats at each killing time; in the lungs, intestines, and mesenteric lymph nodes in 3 of 4 instances; in the tongue, liver, and eyes in 2 instances and in the spleen in 1 instance. Also, using the same procedures and sampling the same 11 tissues as used for rats, tissue cysts were seen in all organs except in the tongue and liver of 3 mice killed on day 82 after feeding the VEG strain. In 9 mice (3 with each strain) fed oocysts of the ME-49, GT-1, or P89 T. gondii strain and killed 62–130 days later, tissue cysts were found consistently only in the brain. Thus, in rats and mice, most tissue cysts were found in the brain and rarely in the tongue. This was in marked contrast to the distribution of tissue cysts in cats.

scholarly journals Imaging the dynamic recruitment of monocytes to the blood–brain barrier and specific brain regions during Toxoplasma gondii infection

2019 ◽  
Vol 116 (49) ◽  
pp. 24796-24807 ◽  
Author(s):  
Christine A. Schneider ◽  
Dario X. Figueroa Velez ◽  
Ricardo Azevedo ◽  
Evelyn M. Hoover ◽  
Cuong J. Tran ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Blood Brain Barrier ◽  
Light Sheet ◽  
Brain Regions ◽  
Brain Barrier ◽  
Cell Segmentation ◽  
Cns Infection ◽  
Light Sheet Microscopy ◽  
Blood Brain ◽  
The Brain

Brain infection by the parasite Toxoplasma gondii in mice is thought to generate vulnerability to predation by mechanisms that remain elusive. Monocytes play a key role in host defense and inflammation and are critical for controlling T. gondii. However, the dynamic and regional relationship between brain-infiltrating monocytes and parasites is unknown. We report the mobilization of inflammatory (CCR2+Ly6Chi) and patrolling (CX3CR1+Ly6Clo) monocytes into the blood and brain during T. gondii infection of C57BL/6J and CCR2RFP/+CX3CR1GFP/+ mice. Longitudinal analysis of mice using 2-photon intravital imaging of the brain through cranial windows revealed that CCR2-RFP monocytes were recruited to the blood–brain barrier (BBB) within 2 wk of T. gondii infection, exhibited distinct rolling and crawling behavior, and accumulated within the vessel lumen before entering the parenchyma. Optical clearing of intact T. gondii-infected brains using iDISCO+ and light-sheet microscopy enabled global 3D detection of monocytes. Clusters of T. gondii and individual monocytes across the brain were identified using an automated cell segmentation pipeline, and monocytes were found to be significantly correlated with sites of T. gondii clusters. Computational alignment of brains to the Allen annotated reference atlas [E. S. Lein et al., Nature 445:168–176 (2007)] indicated a consistent pattern of monocyte infiltration during T. gondii infection to the olfactory tubercle, in contrast to LPS treatment of mice, which resulted in a diffuse distribution of monocytes across multiple brain regions. These data provide insights into the dynamics of monocyte recruitment to the BBB and the highly regionalized localization of monocytes in the brain during T. gondii CNS infection.

Stimuli and consequences of dendritic release of oxytocin within the brain

2007 ◽  
Vol 35 (5) ◽  
pp. 1252-1257 ◽  
Author(s):  
I.D. Neumann
Keyword(s):  
Paraventricular Nucleus ◽  
Stress Responses ◽  
Supraoptic Nucleus ◽  
Brain Regions ◽  
Model System ◽  
Intracerebral Microdialysis ◽  
Psychotherapeutic Intervention ◽  
Psychiatric Illnesses ◽  
Oxytocin Release ◽  
The Brain

The brain oxytocin system has served as a distinguished model system in neuroendocrinology to study detailed mechanisms of intracerebral release, in particular of somatodendritic release, and its behavioural and neuroendocrine consequences. It has been shown that oxytocin is released within various brain regions, but evidence for dendritic release is limited to the main sites of oxytocin synthesis, i.e. the hypothalamic SON (supraoptic nucleus) and PVN (paraventricular nucleus). In the present paper, stimuli of dendritic release of oxytocin and the related neuropeptide vasopressin are discussed, including parturition and suckling, i.e. the period of a highly activated brain oxytocin system. Also, exposure to various pharmacological, psychological or physical stressors triggers dendritic oxytocin release, as monitored by intracerebral microdialysis within the SON and PVN during ongoing behavioural testing. So far, dendritic release of the neuropeptide has only been demonstrated within the hypothalamus, but intracerebral oxytocin release has also been found within the central amygdala and the septum in response to various stimuli including stressor exposure. Such a locally released oxytocin modulates physiological and behavioural reproductive functions, emotionality and hormonal stress responses, as it exerts, for example, pro-social, anxiolytic and antistress actions within restricted brain regions. These discoveries make oxytocin a promising neuromodulator of the brain for psychotherapeutic intervention and treatment of numerous psychiatric illnesses, for example, anxiety-related diseases, social phobia, autism and postpartum depression.

scholarly journals Effects of Toxoplasma gondii Infection on the Brain

2007 ◽  
Vol 33 (3) ◽  
pp. 745-751 ◽  
Author(s):  
V. B. Carruthers ◽  
Y. Suzuki
Keyword(s):  
Toxoplasma Gondii ◽  
Toxoplasma Gondii Infection ◽  
The Brain

scholarly journals Mutant huntingtin reduces vesicular zinc level by inhibiting the binding of Sp1 to ZnT3 promoter

2020 ◽  
Author(s):  
Li Niu ◽  
Shiming Yang ◽  
Weixi Wang ◽  
Cui-fang Ye ◽  
He Li
Keyword(s):  
Molecular Mechanisms ◽  
Early Stage ◽  
Brain Regions ◽  
Zinc Level ◽  
Significant Loss ◽  
Zinc Homeostasis ◽  
Synaptic Dysfunction ◽  
Mutant Huntingtin ◽  
Bhk Cells ◽  
The Brain

Abstract Background Synaptic dysfunction caused by mutant huntingtin greatly contributes to Huntington’s disease (HD) pathogenesis. HD patients show cognitive impairment as well as uncontrolled movements. Vesicular zinc is closely linked to modulating synaptic transmission and maintaining cognitive ability. However, whether does mutant huntingtin affect zinc homeostasis in the brain or not? This will be of great significance for further revealing the pathogenesis of HD. Methods N171-HD82Q transgenic mice and cultured BHK cells expressing N-terminal mutant huntingtin fragment containing 160 glutamines (160Q BHK cells) were used to investigate the effect of mutant huntingtin on zinc homeostasis and its molecular mechanisms. Results Herein, we have demonstrated that the density of synaptic vesicular zinc decreases in the cortex, striatum and hippocampus of N171-82Q mice. Given that vesicular zinc concentration depends on the abundance of zinc transporter 3 (ZnT3) on the membrane of synaptic vesicles, ZnT3 expression is detected in the brain of N171-82Q mice and 160Q BHK cells. Mutant huntingtin leads to a dramatical decrease in ZnT3 mRNA and protein levels in the three brain regions of these mice aged from 14 to 20 weeks. Significantly, Sp1 activates ZnT3 transcription via its binding to the GC boxes in ZnT3 promoter. Nevertheless, mutant huntingtin inhibits the binding of Sp1 to the promoter of ZnT3 gene and down-regulates ZnT3 expression. Furthermore, the overexpression of Sp1 ameliorates inhibition of ZnT3 gene transcription by mutant huntingtin. Conclusions Collectively, this first study to reveal a significant loss of synaptic vesicular zinc and ZnT3 expression caused by mutant huntingtin in the early stage of HD. Our findings have revealed the molecular mechanism underlying this change. Mutant huntingtin inhibits the binding of Sp1 to ZnT3 gene promoter to reduce ZnT3 expression. The imbalance of vesicular zinc homeostasis may be closely associated with synaptic dysfunction and cognitive deficits in HD. This work sheds novel mechanistic insights into the pathogenesis of HD and promises a potential therapeutic strategy for HD.

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