Toxoplasmosis, a disease caused by the parasite Toxoplasma gondii, is one of the most common parasitic infections in the world. In the U.S. it is estimated that more than 22 percent of the population older than age 11 have been infected with toxoplasma, according to the Centers for Disease Control and Prevention.
Now, thanks in part to a five-year, $1.8-million grant from the National Institutes of Health, UGA researcher Silvia Moreno has identified a potential target for new therapies against toxoplasma infection, which may help to protect people with compromised immune systems, developing fetuses and other sensitive populations from serious harm.
Toxoplasma works by invading healthy cells within the body. Once it has taken over, the cell’s membranes protect the parasite from the immune system. However, as it replicates and fills the cell, some parasites must venture out to find new cells to attack. It is during this process, when toxoplasma is outside the protective walls of the host cell, that Moreno sees an opportunity to combat the parasite.
“We are interested in knowing how the parasite is able to survive long enough to find another host cell,” said Moreno, professor of cellular biology in the UGA Center for Tropical and Emerging Global Diseases and the Franklin College of Arts and Sciences.
Moreno’s lab found that while toxoplasma is outside the protective host cell, it develops a large internal organelle called a vacuole that they think may protect the parasite and help it prepare to invade the next cell. Moreno and her collaborators call the organelle a “plant-like vacuole” because it bears resemblance to similar organelles in plants.
For this vacuole to become a target, scientists must first understand the parasite’s basic behaviors and biological functions. They can then start to create new therapies.
“We don’t want to know how the parasite behaves just for the fun of it; we want to know where we can hit it,” Moreno said. “That’s the reason we study its biology because we want to know exactly where to hit toxoplasma with drugs.”
Disrupting the function of the plant-like vacuole may render the parasite incapable of movement. If toxoplasma cannot safely leave the confines of a host cell, it cannot replicate and it cannot create a widespread infection.