Study Explores Toxoplasma gondii’s Host Cell Pathway Regulation

Published January 21, 2014

Ira Jacob Blader, PhD.

Ira Jacob Blader, PhD

Ira Jacob Blader, PhD, associate professor of microbiology and immunology, will build on prior research to identify and explore a host cell pathway essential for the growth of the infection-causing parasite Toxoplasma gondii.

“Understanding how and why T. gondii regulates host cell pathways are key steps toward developing new drugs to treat patients suffering from Toxoplasma infections. ”
Ira Jacob Blader, PhD
Associate professor of microbiology and immunology

The results could aid efforts to develop novel ways of blocking this pathway, or parasite processes dependent on it.

This could pave the way for new therapies to fight devastating infections affecting AIDS and cancer patients as well as fetuses.

Blader has received a $1.18 million, three-year grant from the National Institute of Allergy and Infectious Diseases for the project, “Control of Toxoplasma gondii Growth by the Host Cell Transcription Factor HIF1.”

Revealing Parasite-Host Cell Interactions

Blader and his team will identify and study the role of activin-like kinase (ALK) receptors in Toxoplasma infection.

Parasite signaling via this receptor family drops the host cell’s level of the PHD2 protein.

As the research team demonstrated previously, this occurs when T. gondii activates the transcription factor hypoxia inducible factor-1 (HIF-1) in the host cell — a necessary ingredient for the parasite’s growth.

3 Goals Focus on Intracellular Parasite Processes

The researchers now aim to:

  • establish which ALK receptors function during Toxoplasma infection
  • establish how PHD2 levels are controlled in parasite-infected cells
  • define the parasitic processes dependent on host ALK/HIF-1 signaling

“Understanding how and why T. gondii regulates host cell pathways are key steps toward developing new drugs to treat patients suffering from Toxoplasma infections,” says Blader.

In addition, “these studies are likely to provide important information regarding the interaction between T. gondii and its host cell,” Blader notes.

Widespread Parasite is ‘Ideal’ Study Model

T. gondii causes one of the most widespread infections, affecting half the world’s population.

Although most infected people have no symptoms, those with compromised immune systems face serious, life-threatening illness, Blader notes.

The parasite is commonly found in cat fecal material and can be transmitted by eating undercooked meat. Therefore, it’s important to wash hands after cleaning a litter box, wash vegetables and fully cook meat. 

Studying the pathogen’s mechanisms is particularly valuable because results may reveal information about other diseases, Blader says.

“T. gondii can easily be grown in vitro, its genome has been sequenced and it can be genetically manipulated,” he explains.

“It represents an ideal model system to study disease processes of other, related pathogens, including Plasmodium, which causes malaria, and Cryptosporidium, which causes an important secondary infection in AIDS patients.”