The Clemente Lab

I am a new recruit to the Department of Medical Microbiology and Immunology at the University of Alberta. My lab works in the broad field of Cardiac Immunopathology, trying to study the complex relationship between the heart and the immune system.

Upon sterile or non-sterile injury (infection) of the heart a series of processes, both molecular and cellular, occur that lead to the recruitment into the myocardium and/or activation of cells specialized on defense and repair. This is referred as inflammation and, when it occurs within the myocardium, myocarditis. The evolutionary purpose of inflammation is to defend our tissues against pathogens in order to prevent further damage and to promote, more or less beneficial, reparative programs. However, inflammation is a double-edged sword that can both limit or enhance the tissue damage depending on the circumstances. The defensive mechanisms (i.e: cytotoxic cell death, complement activation or antibody production) and changes in the environment (i.e: pro-inflammatory or pro-fibrotic milieu) can break the homeostasis of highly specialized tissues, like the heart, and affect its function in the short and long run, leading in some cases into heart failure (HF).

We are looking for talented graduate students and postdoc fellows! Interested applicants please send a cover letter, CV, and academic transcript to jclement@ualberta.ca. Some available projects, as well as other FoMD graduate opportunities can be found here.

Cardiac Immune Cell Components

Through the combination of digestion, flow cytometry, and transcriptomics, we have characterized the major populations of macrophages and dendritic cells residing in the heart. The most abundant population of cardiac immune cells during steady state are CD64+MerTK+ macrophages, which can be further divided based on their expression of CCR2 or CD11c. CCR2+macrophages originate from adult bone marrow hematopoiesis, whereas the majority of CCR2- macrophages, which can express high or low levels of MHC-II, are mainly of prenatal origin. Macrophages perform key functions such as repair and removal of debris during injury or supporting electrical connectivity in steady state. A significantly smaller, but important, population of cells residing in the myocardium of healthy individuals is composed of dendritic cells. The two major subsets of cardiac conventional DCs (cDCs) have been recently characterized: cDC1 (CD103+ DCs) and cDC2 (CD11b+ DCs). DCs play important roles in defense against infection but can also promote self-injury during inflammation, particularly during myocardial infarction.