Uncovering Genetic Variants That May Protect Amazonian Populations Against Chagas Disease

A new study led by Vanderbilt University professor Amanda Lea has identified genetic variants that may be responsible for protecting Amazonian populations against Chagas disease. By analyzing the genomes of 118 individuals from 19 Indigenous populations in Brazil, the team found a high-frequency variant of the PPP3CA gene in Amazonian populations that could be responsible for this resistance.[0]

In order to ascertain whether PPP3CA is linked to susceptibility to Chagas disease, scientists exposed cultured human heart cells to T. cruzi.[1] Research revealed that, typically, the cells with reduced expression of the gene had 25% fewer parasites infecting them, indicating that the gene does contribute to the parasite's capacity to enter the cell.[1] This is the first experimental evidence that this gene is involved with Chagas disease.[1]

The PPP3CA gene is responsible for producing a vital protein implicated in the triggering of immune cells, the innate immune reaction, and the uptake of the T.cruzi parasite in human cells.[0] This gene variant likely evolved to protect Amazonian populations against Chagas disease.[2]

The research also uncovered genetic variants that positively affect the way Tsimane’s use energy.[3] While deleterious alleles in U.S. or European populations, such as Apolipoprotein-E4, have been linked to an increased risk for Alzheimer’s disease, they may have a muted—or even positive—effect in an environment with many infectious agents and limited energy.[3]

Overall, the findings of this study provide insights into the population's adaptation to the Amazonian rainforest and contribute to the dissection of the molecular mechanisms of pathogen infection and the potential development of therapies for the disease.[2]

0. “Genetic adaptations help Amazonian populations resist Chagas infection” Medical Xpress, 8 Mar. 2023, https://medicalxpress.com/news/2023-03-genetic-amazonian-populations-resist-chagas.html

1. “Indigenous groups in the Amazon evolved resistance to deadly Chagas” Science, 8 Mar. 2023, https://www.science.org/content/article/indigenous-groups-amazon-evolved-resistance-deadly-chagas

2. “Chagas Disease Protective Variant Found in Indigenous Amazon Populations” GenomeWeb, 8 Mar. 2023, https://www.genomeweb.com/sequencing/chagas-disease-protective-variant-found-indigenous-amazon-populations

3. “Study Finds Modes of Natural Selection in Understudied Human Populations” Laboratory Equipment, 2 Mar. 2023, https://www.laboratoryequipment.com/594913-Study-Finds-Modes-of-Natural-Selection-in-Understudied-Human-Populations/

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