Antoine Dufour, PhD
The goal of my lab is to understand how proteolytic post-translational modifications lead to the activation or inactivation of immune responses in inflammatory diseases. By the irreversible processing of bioactive proteins and signaling molecules, proteases modulate all aspects of biology. We focus on proteases and their substrates on a cell, tissue, biopsy or organism-wide scale.
1- Unraveling how calcium signaling regulates calpain proteolytic networks
Selected proteins have evolved to bind Ca2+ to buffer its levels, and alterations in Ca2+ homeostasis initiate or terminate multiple cellular signaling pathways that govern cell shape, adhesion, migration, and viability. Activation of G protein-coupled receptors (GPCRs) can trigger intracellular Ca2+ release through the downstream generation of 1,4,5-inositol trisphosphate (IP3). When IP3 binds to its cognatereceptor (IP3R) in the endoplasmic reticulum, Ca2+ concentrations rise from ~100 nM to more than 1 mM (>10-fold increase) dictating profound changes on cellular functions. Among the key downstream effectors of Ca2+ signaling are a family of 15 cysteine proteases called calpains, which are directly activated at their catalytic sites by changes in intracellular Ca2+ levels. These proteases regulate diverse cellular processes through targeted proteolysis and precise processing of multiple protein substrates. We are using systems biology approaches to identify novel calpain substrates and understand their effect on cellular functions and immune signaling.
2- Multi-omics analysis of macrophage polarization
Tissues are an interactive, multi-cell and dynamic environment linked to the surrounding stroma by signaling networks that regulate gene and protein expression as well as post-translational modifications. Within inflamed joints, wounds or tumors, immune cells collaborate to this highly dynamic environment by modulating the genetic landscape and web of proteins as they are reacting to the threat. Among the multitude of infiltrating immune cells, mononuclear phagocytes are necessary for the clearance of pathogens and the resolution of inflammation during innate and adaptive immunity. The mononuclear phagocyte system is a highly dynamic and complex system that can be unified based upon progenitor cells but disjointed based upon the stimuli they are responding to. They are responsive and activated by various cell products and cytokines thus giving rise to a panoply of populations with distinct functions. The classically activated macrophages are induced by IFNg and/or LPS (TH1) whereas alternatively activated macrophages (TH2) have several activators including IL4, IL13, IL10, glucocorticoids (GC), immune complexes (IC) and/or transforming growth factor ? (TGF?). To understand the global changes of macrophage reactivity and their substrates within whole tissues or fluids, wide-scale systems biology approaches offer the opportunity to integrate and capture such complexity. Extensive transcriptomics information has been published in the last decade but still little is known about the partitioned macrophage populations’ proteome and their protease substrates.
Techniques used in our laboratory:
mouse models of peritonitis, cancer and arthritis, calcium assay, cell migration/invasion, immunohistochemistry, TAILS (Terminal Amino Isotopic Labeling of Substrates), PICS (Proteomic Identification of protease Cleavage Sites), TopFINDER, PathFINDer
Dr. Antoine Dufour has joined the Department of Physiology and Pharmacology as an Assistant Professor. Dr. Dufour obtained his BA (Hons.) in Chemistry from the State University of New York at Oswego, his MSc and PhD in Chemical Biology from the Stony Brook University (2010). He completed a Postdoctoral Fellowship in Biochemistry at the University of British Columbia in 2017 under the supervision of Dr. Chris Overall. Antoine’s research is focused on the role of proteases in immunity and novel drug target identification in inflammatory musculoskeletal diseases, with a particular interest in quantitative mass spectrometry and systems biology. He owns two patents for the inhibitory methods of protease-mediated cell migration. His research program aims to understand the key mechanisms of inflammatory and immune responses in musculoskeletal diseases. Antoine has already published 20 journal papers, 3 book chapters and has an outstanding track record of academic awards. Dr. Dufour’s lab and office space is located at the Centre for Mobility and Joint Health on the third floor of the HRIC building.