Toxoplasma gondii protects from IgE sensitization and induces Th1/Th2 immune profile

Unveiling of brain transcriptome of masked palm civet (Paguma larvata) with chronic infection of Toxoplasma gondii

BACKGROUND

The aim of this study was to gain an understanding of the transcriptomic changes that occur in a wild species when infected with Toxoplasma gondii. The masked palm civet, an artifically domesticated animal, was used as the model of a wild species. Transcriptome analysis was used to study alterations in gene expression in the domesticated masked palm civet after chronic infection with T. gondii.

METHODS

Masked palm civets were infected with 10⁵ T. gondii cysts and their brain tissue collected after 4 months of infection. RNA sequencing (RNA-Seq) was used to gain insight into the spectrum of genes that were differentially expressed due to infection. Quantitative reverse-transcription PCR (qRT-PCR) was also used to validate the level of expression of a set of differentially expressed genes (DEGs) obtained by sequencing.

RESULTS

DEGs were screened from the sequencing results and analyzed. A total of 2808 DEGs were detected, of which 860 were upregulated and 1948 were downregulated. RNA-Seq results were confirmed by qRT-PCR. DEGs were mainly enriched in cellular process and metabolic process based on gene ontology enrichment analysis. Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that transcriptional changes in the brain of infected masked palm civets evolved over the course of infection and that DEGs were mainly enriched in the signal transduction, immune system processes, transport and catabolic pathways. Finally, 10 essential driving genes were identified from the immune signaling pathway.

CONCLUSIONS

This study revealed novel host genes which may provide target genes for the development of new therapeutics and detection methods for T. gondii infection in wild animals.

Pediatric hypereosinophilia and toxoplasma: Peregrination beyond facileness

Evaluation of pediatric hypereosinophilia (HE) is challenging, especially in the tropical developing countries, as appropriate diagnostic facilities may be lacking, parasitic/helminthic infections are common, and existing data on the etiology of severe eosinophilia are sparse. Second, data on long-term follow-up of these children including the temporal course of eosinophilia are also scarce. Besides, questions regarding the coexistence of multiple etiologies and their association with the severity of HE are largely unexplored. These challenges and questions often lead to diagnostic and therapeutic dilemmas. We highlight these difficulties utilizing a real-life clinical description. We emphasize the need for long-term follow-up of such children as HE may be the combinatorial effect of multiple etiologies, rather than a single cause. We also describe an unusual association of severe eosinophilia in a child with toxoplasmosis that was treated successfully with 8-week combination therapy with azithromycin and cotrimoxazole (sulfadiazine and pyrimethamine were not available).

Understanding Asthma and Allergies by the Lens of Biodiversity and Epigenetic Changes

Exposure to different organisms (bacteria, mold, virus, protozoan, helminths, among others) can induce epigenetic changes affecting the modulation of immune responses and consequently increasing the susceptibility to inflammatory diseases. Epigenomic regulatory features are highly affected during embryonic development and are responsible for the expression or repression of different genes associated with cell development and targeting/conducting immune responses. The well-known, "window of opportunity" that includes maternal and post-natal environmental exposures, which include maternal infections, microbiota, diet, drugs, and pollutant exposures are of fundamental importance to immune modulation and these events are almost always accompanied by epigenetic changes. Recently, it has been shown that these alterations could be involved in both risk and protection of allergic diseases through mechanisms, such as DNA methylation and histone modifications, which can enhance Th2 responses and maintain memory Th2 cells or decrease Treg cells differentiation. In addition, epigenetic changes may differ according to the microbial agent involved and may even influence different asthma or allergy phenotypes. In this review, we discuss how exposure to different organisms, including bacteria, viruses, and helminths can lead to epigenetic modulations and how this correlates with allergic diseases considering different genetic backgrounds of several ancestral populations.