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Arthur Mortha

Associate Professor

Temerty Faculty of Medicine, Department of Immunology

Orcid identifier0000-0003-2673-0485
  • Associate Professor
    Temerty Faculty of Medicine, Department of Immunology
  • (416) 978-6245 (Work)
  • University of Toronto, St. George Campus, Medical Sciences Building, 1 King's College Circle, Room 7326, Toronto, Ontario, M5S 1A8, Canada

BIO

Dr. Arthur Mortha studied Biology and Chemistry at the Friedrich Alexander University in Erlangen, Germany, where he obtained a Master’s in Biology working on the regulation of B cell antigen-receptor selection at the pre-B cell receptor level.

He then conducted his Ph.D. thesis in the laboratory of Professor Andreas DIefenbach at the Albert-Ludwigs University in Freiburg Germany in 2011, where he contributed to the identification, developmental and functional characterization of a new lymphocyte subset now known as natural cytotoxicity receptor-expressing innate lymphoid cells or ILC3s. His investigations revealed a critical role for the transcription factor “ROR gamma t” in controlling the development of these cells. ROR gamma t positive ILC3 supported intestinal epithelial homeostasis through their production of IL-22. His work also demonstrated that the transcriptional program driven by ROR gamma t was not stable and could generate inflammatory ILCs that promoted inflammatory bowel disease. These findings were published in Nature Immunology and Immunity.

Dr. Mortha then proceed to join the laboratory of Professor Miriam Merad at the Mount Sinai Hospital in New York, an expert in the field of myeloid cells to understand how the crosstalk between ILCs and myeloid cells could synergize to maintain a healthy intestine.

He was able to demonstrate that gut macrophages are critical in sensing intestinal commensals and this recognition promoted ILC3s to produce a myeloid growth and differentiation factor call GM-CSF. ILC3-derived GM-CSF in turn was sufficient to promote the functional reprogramming of dendritic cells that generated regulatory T cells specific to orally ingested antigens. These findings were among the first to demonstrate how the gut microbiome instructs tolerance to food antigens.

Following his interest in the gut microbiome, Dr. Mortha identified a previously unknown commensal microbe called Tritrichomonas musculis with superior abilities to reshapes the intestinal immune landscape following colonization. The underlying immune changes exacerbated autoimmune-mediated intestinal inflammation while suppressing pathogen driven pathology suggesting a possible role for protozoan commensals to serve as “natural antibiotic”.

MEDIA

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DEGREES

  • Ph.D., Immunology
    University of Freiburg, Freiburg, Germany2007 - 2011

POSTGRADUATE TRAINING

  • Post-Doctoral Fellow
    Icahn School of Medicine at Mount Sinai, Immunology, New York, United States2011 - 2016
    The interaction of innate lymphoid cells and myeloid cellsSupervised by Merad M

INSTITUTIONAL STRATEGIC INITIATIVES

  • EPIC (Emerging and Pandemic Infections Consortium)
  • PRiME (Precision Medicine Initiative)