Rallying the Troops: A prepared immune system is better armed for a pathogen attack

Photo of Truc Losier in the Ryan Russell lab.

Research led by PhD student Truc Losier has critical implications for the study of immune diseases such as Crohn’s.

Research led by a graduate student at the uOttawa Faculty of Medicine, and recently published in Cell Reports and selected for research highlight in Autophagy, has uncovered evidence that the immune system is warned of pathogens before they invade—a discovery with critical implications for the study of immune diseases such as Crohn’s.

Canada is burdened with the highest rate of Crohn’s disease in the world, and the work of promising young researchers like Truc Losier of the Department of Cellular and Molecular Medicine (CMM) brings hope to those suffering. In fact, Losier’s new paper, out of CMM assistant professor Ryan Russell’s lab, has opened novel avenues of research for scientists seeking answers about such immune-related diseases.

In their paper, Losier et al. reveal their discovery of a new cellular defense pathway activated when a pathogen invades the body. Until now, scientists believed that the cellular defense known as autophagy was only triggered when bacteria invaded a cell. However, the team’s newly discovered pathway is able to sense a pathogen in advance of its invasion.

This pathway is triggered when it senses nanometer-sized spheres of bacterial membranes and proteins of an incoming pathogen; once triggered, the pathway sends a heads-up to the autophagy pathway even before the bacteria invades—allowing cells to ready themselves for attack.

An early response to a pathogen allows the cells to capture and target bacteria for degradation before they have a chance to replicate and harm the hosts. Understanding this cellular defense mechanism and the drug targets that can manipulate it is of significant interest for future applications. Notably, the repurposing of Health Canada-approved drugs may be of interest in a subset of Crohn’s patients.

A master’s student at the time of the paper’s publishing, Losier is now a PhD student in Dr. Russell’s lab under an Ontario Graduate Scholarship, awarded for her excellence in graduate studies. EMBO Reports has recently accepted her second paper, featuring new insights into signaling in Crohn’s disease.


Main photo credit: Chonglu Huang

Photo of Truc Losier and Dr. Ryan Russell in their lab.

PhD student Truc Losier (left) and Dr. Ryan Russell discuss Losier’s results. Photo credit: Chonglu Huang


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