Can An Infection Alter Your Epigenome? | What is Epigenetics?

Working in a cell-based culture system, researchers have been able to confirm that cells infected with the Toxoplasma parasite exhibit dramatic changes in gene expression. The parasite appears to modulate host gene expression through the activities of secreted proteins that it injects into the host cell. Toxoplasma can bewitch its host cell to arrest the cell cycle, block apoptosis, or, in the case of certain immune cells, cause them to become motile, thereby helping the parasite disseminate throughout the body.

So how might Toxoplasma hijack the host cell to do the parasite’s bidding? It has been shown that some of these parasite-secreted proteins alter signal transduction cascades that ultimately change gene expression, presumably through an epigenetic component. Recent studies lend support to this idea by showing how Toxoplasma infection has the potential to alter both DNA methylation and histone acetylation, modifications that repress or activate genes, respectively.

In a 2014 study, Hari Dass and Vyas noted diminished DNA methylation of the arginine vasopressin promoter in the medial amygdala of infected male rats, which may contribute to the loss of fear in response to cat odors. Interestingly, the aversion to cat odors in infected rats can be reversed with systemic hypermethylation.

No comments: