Publisher Correction: Toxoplasma Modulates Signature Pathways of Human Epilepsy, Neurodegeneration & Cancer.

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Toxoplasma Modulates Signature Pathways of Human Epilepsy, Neurodegeneration & Cancer.

One third of humans are infected lifelong with the brain-dwelling, protozoan parasite, Toxoplasma gondii. Approximately fifteen million of these have congenital toxoplasmosis. Although neurobehavioral disease is associated with seropositivity, causality is unproven. To better understand what this parasite does to human brains, we performed a comprehensive systems analysis of the infected brain: We identified susceptibility genes for congenital toxoplasmosis in our cohort of infected humans and found these genes are expressed in human brain. Transcriptomic and quantitative proteomic analyses of infected human, primary, neuronal stem and monocytic cells revealed effects on neurodevelopment and plasticity in neural, immune, and endocrine networks. These findings were supported by identification of protein and miRNA biomarkers in sera of ill children reflecting brain damage and T. gondii infection. These data were deconvoluted using three systems biology approaches: "Orbital-deconvolution" elucidated upstream, regulatory pathways interconnecting human susceptibility genes, biomarkers, proteomes, and transcriptomes. "Cluster-deconvolution" revealed visual protein-protein interaction clusters involved in processes affecting brain functions and circuitry, including lipid metabolism, leukocyte migration and olfaction. Finally, "disease-deconvolution" identified associations between the parasite-brain interactions and epilepsy, movement disorders, Alzheimer's disease, and cancer. This "reconstruction-deconvolution" logic provides templates of progenitor cells' potentiating effects, and components affecting human brain parasitism and diseases.

ALOX12 in human toxoplasmosis.

ALOX12 is a gene encoding arachidonate 12-lipoxygenase (12-LOX), a member of a nonheme lipoxygenase family of dioxygenases. ALOX12 catalyzes the addition of oxygen to arachidonic acid, producing 12-hydroperoxyeicosatetraenoic acid (12-HPETE), which can be reduced to the eicosanoid 12-HETE (12-hydroxyeicosatetraenoic acid). 12-HETE acts in diverse cellular processes, including catecholamine synthesis, vasoconstriction, neuronal function, and inflammation. Consistent with effects on these fundamental mechanisms, allelic variants of ALOX12 are associated with diseases including schizophrenia, atherosclerosis, and cancers, but the mechanisms have not been defined. Toxoplasma gondii is an apicomplexan parasite that causes morbidity and mortality and stimulates an innate and adaptive immune inflammatory reaction. Recently, it has been shown that a gene region known as Toxo1 is critical for susceptibility or resistance to T. gondii infection in rats. An orthologous gene region with ALOX12 centromeric is also present in humans. Here we report that the human ALOX12 gene has susceptibility alleles for human congenital toxoplasmosis (rs6502997 [P, <0.000309], rs312462 [P, <0.028499], rs6502998 [P, <0.029794], and rs434473 [P, <0.038516]). A human monocytic cell line was genetically engineered using lentivirus RNA interference to knock down ALOX12. In ALOX12 knockdown cells, ALOX12 RNA expression decreased and levels of the ALOX12 substrate, arachidonic acid, increased. ALOX12 knockdown attenuated the progression of T. gondii infection and resulted in greater parasite burdens but decreased consequent late cell death of the human monocytic cell line. These findings suggest that ALOX12 influences host responses to T. gondii infection in human cells. ALOX12 has been shown in other studies to be important in numerous diseases. Here we demonstrate the critical role ALOX12 plays in T. gondii infection in humans.

Spinal Cord Lesions in Congenital Toxoplasmosis Demonstrated with Neuroimaging, Including Their Successful Treatment in an Adult.

Neuroimaging studies for persons in the National Collaborative Chicago-Based Congenital Toxoplasmosis Study (NCCCTS) with symptoms and signs referable to the spinal cord were reviewed. Three infants had symptomatic spinal cord lesions, another infant a Chiari malformation, and another infant a symptomatic peri-spinal cord lipoma. One patient had an unusual history of prolonged spinal cord symptoms presenting in middle age. Neuroimaging was used to establish her diagnosis and response to treatment. This 43 year-old woman with congenital toxoplasmosis developed progressive leg spasticity, weakness, numbness, difficulty walking, and decreased visual acuity and color vision without documented re-activation of her chorioretinal disease. At 52 years of age, spinal cord lesions in locations correlating with her symptoms and optic atrophy were diagnosed with 3 Tesla MRI scan. Treatment with pyrimethamine and sulfadiazine decreased her neurologic symptoms, improved her neurologic examination, and resolved her enhancing spinal cord lesions seen on MRI.

Lesões coriorretinianas em mães de crianças com toxoplasmose congênita no national collaborative Chicago-based, toxoplasmosis study / Chorioretinal lesions in mothers of children with congenital toxoplasmosis in the national collaborative Chicago-based, congenital toxoplasmosis study

Aims: To determine whether mothers of children with congenital toxoplasmosis have chorioretinal lesions consistent with toxoplasmosis. Methods: Prospective cohort study. Ophthalmologists in our study have examined 173 children with congenital toxoplasmosis in a hospital outpatient setting. These children were referred to us by their primary care physicians. One hundred and thirty mothers of these children had retina examinations of both eyes at least once. Main outcome measure was lesion(s) consistent with ocular toxoplasmosis. Results: Of 130 mothers examined between 1991-2005, 10 (7.7%, 95% Confidence Interval 3.8%, 13.7%) had chorioretinal lesions which likely represent resolved toxoplasmic chorioretinitis. Most of these were small peripheral chorioretinal lesions. None reactivated between 1991-2005. Conclusions: Chorioretinal lesions consistent with quiescent ocular toxoplasmosis occur in mothers of children with congenital toxoplasmosis in the United States.

Cataracts in congenital toxoplasmosis.

PURPOSE: To determine the incidence and natural history of cataracts in children with congenital toxoplasmosis. METHODS: Children referred to the National Collaborative Chicago-based Congenital Toxoplasmosis Study (NCCCTS) between 1981 and 2005 were examined by ophthalmologists at predetermined times according to a specific protocol. The clinical course and treatment of patients who developed cataracts were reviewed. RESULTS: In the first year of life, 134 of 173 children examined were treated with pyrimethamine, sulfadiazine, and leukovorin, while the remaining 39 were not treated. Cataracts occurred in 27 eyes of 20 patients (11.6%, 95% confidence interval [7.2%, 17.3%]). Fourteen cataracts were present at birth and 13 developed postnatally. Locations of the cataracts included anterior polar (three eyes), anterior subcapsular (six eyes), nuclear (five eyes), posterior subcapsular (seven eyes), and unknown (six eyes). Thirteen cataracts were partial, nine total, and five with unknown complexity. Twelve cataracts remained stable, 12 progressed, and progression was not known for 3. Five of 27 eyes had cataract surgery, with 2 of these developing glaucoma. Sixteen eyes of 11 patients had retinal detachment and cataract. All eyes with cataracts had additional ocular lesions. CONCLUSIONS: In the NCCCTS cohort, 11.6% of patients were diagnosed with cataracts. There was considerable variability in the presentation, morphology, and progression of the cataracts. Associated intraocular pathology was an important cause of morbidity.