Human Retinal Organoid Model of Ocular Toxoplasmosis

The health burden of ocular toxoplasmosis is substantial, and there is an unmet need for safe and curative anti-microbial drugs. One major barrier to research on new therapeutics is the lack of in vitro human-based models beyond two-dimensional cultured cells and tissue explants. We aimed to address...

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Main Authors: Liam M. Ashander, Grace E. Lidgerwood, Amanda L. Lumsden, João M. Furtado, Alice Pébay, Justine R. Smith
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Pathogens
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Online Access:https://www.mdpi.com/2076-0817/14/3/286
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author Liam M. Ashander
Grace E. Lidgerwood
Amanda L. Lumsden
João M. Furtado
Alice Pébay
Justine R. Smith
author_facet Liam M. Ashander
Grace E. Lidgerwood
Amanda L. Lumsden
João M. Furtado
Alice Pébay
Justine R. Smith
author_sort Liam M. Ashander
collection DOAJ
description The health burden of ocular toxoplasmosis is substantial, and there is an unmet need for safe and curative anti-microbial drugs. One major barrier to research on new therapeutics is the lack of in vitro human-based models beyond two-dimensional cultured cells and tissue explants. We aimed to address this research gap by establishing a human retinal organoid model of ocular toxoplasmosis. Retinal organoids, generated from human induced pluripotent stem cells and grown to two stages of organization, were incubated with a suspension of live or heat-killed GT-1 strain <i>T. gondii</i> tachyzoites, or medium without tachyzoites. Both developing (1 month post-isolation) and matured (6 months post-isolation) organoids were susceptible to infection. Spread of live parasites from the margin to the entire organoid over 1 week was indicated by immunolabelling for <i>T. gondii</i> surface antigen 1. This progression was accompanied by changes in the levels of selected tachyzoite transcripts—<i>SAG1</i>, <i>GRA6</i>, and <i>ROP16</i>—and human cytokine transcripts—<i>CCL2</i>, <i>CXCL8</i>, <i>CXCL10</i>, and <i>IL6</i>—in infected versus control conditions. Our human retinal organoid model of ocular toxoplasmosis offers the opportunity for many future lines of study, including tachyzoite interactions with retinal cell populations and leukocyte subsets, parasite stage progression, and disease processes of different <i>T. gondii</i> strains, as well as drug testing.
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spelling doaj-art-ccb0d444b5294e7cbc3367340ad55faa2025-08-20T02:42:28ZengMDPI AGPathogens2076-08172025-03-0114328610.3390/pathogens14030286Human Retinal Organoid Model of Ocular ToxoplasmosisLiam M. Ashander0Grace E. Lidgerwood1Amanda L. Lumsden2João M. Furtado3Alice Pébay4Justine R. Smith5Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Adelaide, SA 5042, AustraliaDepartment of Anatomy and Physiology, The University of Melbourne, Parkville, VIC 3010, AustraliaFlinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Adelaide, SA 5042, AustraliaDivision of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, São Paulo, BrazilDepartment of Anatomy and Physiology, The University of Melbourne, Parkville, VIC 3010, AustraliaFlinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Adelaide, SA 5042, AustraliaThe health burden of ocular toxoplasmosis is substantial, and there is an unmet need for safe and curative anti-microbial drugs. One major barrier to research on new therapeutics is the lack of in vitro human-based models beyond two-dimensional cultured cells and tissue explants. We aimed to address this research gap by establishing a human retinal organoid model of ocular toxoplasmosis. Retinal organoids, generated from human induced pluripotent stem cells and grown to two stages of organization, were incubated with a suspension of live or heat-killed GT-1 strain <i>T. gondii</i> tachyzoites, or medium without tachyzoites. Both developing (1 month post-isolation) and matured (6 months post-isolation) organoids were susceptible to infection. Spread of live parasites from the margin to the entire organoid over 1 week was indicated by immunolabelling for <i>T. gondii</i> surface antigen 1. This progression was accompanied by changes in the levels of selected tachyzoite transcripts—<i>SAG1</i>, <i>GRA6</i>, and <i>ROP16</i>—and human cytokine transcripts—<i>CCL2</i>, <i>CXCL8</i>, <i>CXCL10</i>, and <i>IL6</i>—in infected versus control conditions. Our human retinal organoid model of ocular toxoplasmosis offers the opportunity for many future lines of study, including tachyzoite interactions with retinal cell populations and leukocyte subsets, parasite stage progression, and disease processes of different <i>T. gondii</i> strains, as well as drug testing.https://www.mdpi.com/2076-0817/14/3/286uveitisretinitisocular toxoplasmosis
spellingShingle Liam M. Ashander
Grace E. Lidgerwood
Amanda L. Lumsden
João M. Furtado
Alice Pébay
Justine R. Smith
Human Retinal Organoid Model of Ocular Toxoplasmosis
Pathogens
uveitis
retinitis
ocular toxoplasmosis
title Human Retinal Organoid Model of Ocular Toxoplasmosis
title_full Human Retinal Organoid Model of Ocular Toxoplasmosis
title_fullStr Human Retinal Organoid Model of Ocular Toxoplasmosis
title_full_unstemmed Human Retinal Organoid Model of Ocular Toxoplasmosis
title_short Human Retinal Organoid Model of Ocular Toxoplasmosis
title_sort human retinal organoid model of ocular toxoplasmosis
topic uveitis
retinitis
ocular toxoplasmosis
url https://www.mdpi.com/2076-0817/14/3/286
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