3-D Imaging and Analysis of Neurons Infected &lt;em&gt;In Vivo&lt;/em&gt; with &lt;em&gt;Toxoplasma gondii&lt;/em&gt;

Koshy, Anita A.; Cabral, Carla M.

doi:10.3791/52237

Cited by 19 publications

(19 citation statements)

References 19 publications

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“…We have not observed a predilection of T gondii infection for any particular cell type, concurring with in vitro studies using rodent and human cells that show cyst formation in both neurons and astrocytes (57,58). It is known that cysts in neuronal processes usually result in neurite and synapse loss (52,59). This is in agreement with our data showing that T. gondii infection reduced the synaptophysin mRNA levels compared to non-infected BrainSpheres, which can be interpreted as a reduction in synapse density.…”

Section: Discussionsupporting

confidence: 88%

Morphological and biochemical repercussions ofToxoplasma gondiiinfection in a 3D human brain neurospheres model

Leite

Portes

Pereira

et al. 2020

Preprint

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BackgroundToxoplasmosis is caused by the parasite Toxoplasma gondii that can infect the central nervous system (CNS), promoting neuroinflammation, neuronal loss, neurotransmitter imbalance and behavioral alterations. T. gondii infection is also related to neuropsychiatric disorders such as schizophrenia. The pathogenicity and inflammatory response in rodents are different to the case of humans, compromising the correlation between the behavioral alterations and physiological modifications observed in the disease. In the present work we used BrainSpheres, a 3D CNS model derived from human pluripotent stem cells (iPSC), to investigate the morphological and biochemical repercussions of T. gondii infection in human neural cells.MethodsWe evaluated T. gondii ME49 strain proliferation and cyst formation in both 2D cultured human neural cells and BrainSpheres. Aspects of cell morphology, ultrastructure, viability, gene expression of neural phenotype markers, as well as secretion of inflammatory mediators were evaluated for 2 and 4 weeks post infection in BrainSpheres.ResultsT. gondii can infect BrainSpheres, proliferating and inducing cysts formation, neural cell death, alteration in neural gene expression and triggering the release of several inflammatory mediator.ConclusionsBrainSpheres reproduce many aspects of T. gondii infection in human CNS, constituting a useful model to study the neurotoxicity and neuroinflammation mediated by the parasite. In addition, BrainSpheres can be an important tool for better understanding the possible correlation between psychiatric disorders and human CNS infection with T. gondii

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Section: Discussionsupporting

confidence: 88%

Morphological and biochemical repercussions ofToxoplasma gondiiinfection in a 3D human brain neurospheres model

Leite

Portes

Pereira

et al. 2020

Preprint

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“…Protozoan parasites possess survival strategies to maintain viability inside and outside the host(s) by forming cyst structures (38,39). Neurons are the primary target cells for Toxoplasma cyst formation within distal neuronal processes (40,41). Bradyzoite differentiation is triggered by changes in nutrition or cellular conditions (42)(43)(44), which drives the transcriptional program that leads to the production of bradyzoite-stage proteins (45,46) and the formation of the cyst wall and cyst structure (32).…”

Section: Discussionmentioning

confidence: 99%

Succinylated Wheat Germ Agglutinin Colocalizes with the Toxoplasma gondii Cyst Wall Glycoprotein CST1

Guevara

Fox

Bzik

2020

mSphere

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The glycosylated mucin domain of the Toxoplasma gondii cyst wall glycoprotein CST1 is heavily stained by Dolichos biflorus agglutinin, a lectin that binds to N-acetylgalactosamine. The cyst wall is also heavily stained by the chitin binding lectin succinylated wheat germ agglutinin (s-WGA), which selectively binds to N-acetylglucosamine-decorated structures. Here, we tracked the localization of N-acetylglucosamine-decorated structures that bind to s-WGA in immature and mature in vitro cysts. s-WGA localization was observed at the cyst periphery 6 h after the differentiation of the tachyzoite-stage parasitophorous vacuole. By day 1 and at all later times after differentiation, s-WGA was localized in a continuous staining pattern at the cyst wall. Coinciding with the maturation of the cyst matrix by day 3 of cyst development, s-WGA also localized in a continuous matrix pattern inside the cyst. s-WGA localized in both the outer and inner layer regions of the cyst wall and in a continuous matrix pattern inside mature 7-and 10-day-old cysts. In addition, s-WGA colocalized in the cyst wall with CST1, suggesting that N-acetylglucosamineand N-acetylgalactosamine-decorated molecules colocalized in the cyst wall. In contrast to CST1, GRA4, and GRA6, the relative accumulation of the molecules that bind s-WGA in the cyst wall was not dependent on the expression of GRA2. Our results suggest that GRA2-dependent and GRA2-independent mechanisms regulate the trafficking and accumulation of glycosylated molecules that colocalize in the cyst wall. IMPORTANCE Chronic Toxoplasma gondii infection is maintained in the central nervous system by thick-walled cysts. If host immunity wanes, cysts recrudesce and cause severe and often lethal toxoplasmic encephalitis. Currently, there are no therapies to eliminate cysts, and little biological information is available regarding cyst structure(s). Here, we investigated cyst wall molecules recognized by succinylated wheat germ agglutinin (s-WGA), a lectin that specifically binds to N-acetylglucosamine-decorated structures. N-Acetylglucosamine regulates cell signaling and plays structural roles at the cell surface in many organisms. The cyst wall and cyst matrix were heavily stained by s-WGA in mature cysts and were differentially stained during cyst development. The relative accumulation of molecules that bind to s-WGA in the cyst wall was not dependent on the expression of GRA2. Our findings suggest that glycosylated cyst wall molecules gain access to the cyst wall via GRA2-dependent and GRA2-independent mechanisms and colocalize in the cyst wall.

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“…Toxoplasma gondii tachyzoites are capable of invading microglia, astrocytes, and neurons [13]; the parasite thereafter forms cysts within these cells [14, 15]. Parasite strains can differ greatly in their aggressiveness during infection and in their propensity to form cysts for long-term survival [16].…”

Section: Introductionmentioning

confidence: 99%

Latent toxoplasmosis is associated with neurocognitive impairment in young adults with and without chronic HIV infection

Ene

Marcotte

Umlauf

et al. 2016

Journal of Neuroimmunology

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We evaluated the impact of latent toxoplasmosis (LT) on neurocognitive (NC) and neurobehavioural functioning in young adults with and without chronic HIV infection, using a standardised NC test battery, self-reported Beck Depression Inventory, Frontal System Behaviour Scale, MINI-International Neuropsychiatric Interview and risk-assessment battery. 194 young adults (median age 24 years, 48.2% males) with chronic HIV infection (HIV+) since childhood and 51 HIV seronegative (HIV-) participants were included. HIV+ individuals had good current immunological status (median CD4: 479 cells/μL) despite a low CD4 nadir (median: 93 cells/μL). LT (positive anti-Toxoplasma IgG antibodies) was present in one third of participants. The impairment rates in the HIV- with and without Toxo were not significantly different (p=0.17). However, we observed an increasing trend (p<0.001) in impairment rates with HIV and LT status: HIV-/LT- (6.1%); HIV-/LT+ (22%), HIV+/LT- (31%), HIV+/LT+ (49%). In a multivariable analysis using the entire study group there were main effects on cognition for HIV and also for LT. Within the HIV+ group LT was associated with worse performance globally (p=0.006), in memory (p=0.009), speed of information processing (p=0.01), verbal (p=0.02) and learning (p=0.02) domains. LT was not associated with depressive symptoms, frontal systems dysfunction or risk behaviors in any of the groups. HIV participants with lower Toxoplasma antibody concentration had worse NC performance, with higher GDS values (p=0.03) and worse learning (p=0.002), memory (p=0.006), speed of information processing (p=0.01) T scores. Latent Toxoplasmosis may contribute to NC impairment in young adults, including those with and without chronic HIV infection.

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3-D Imaging and Analysis of Neurons Infected <em>In Vivo</em> with <em>Toxoplasma gondii</em>

Cited by 19 publications

References 19 publications

Morphological and biochemical repercussions ofToxoplasma gondiiinfection in a 3D human brain neurospheres model

Morphological and biochemical repercussions ofToxoplasma gondiiinfection in a 3D human brain neurospheres model

Succinylated Wheat Germ Agglutinin Colocalizes with the Toxoplasma gondii Cyst Wall Glycoprotein CST1

Latent toxoplasmosis is associated with neurocognitive impairment in young adults with and without chronic HIV infection

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