Dr. Paul Forsythe

Division of Respirology

Paul Forsythe

M.Sc., Ph.D.

Assistant Professor, Division of Respirology, Department of Medicine






Education and Professional Standing Awards and Distinctions

Dr Paul Forsythe obtained his BSc (Hons) in Biochemistry MSc in Laboratory Medicine and PhD in Mast Cell Immunopharmacology from Queen’s University Belfast, Northern Ireland. Following his PhD he undertook a post-doctoral fellowship with the Pulmonary Research Group at the University of Alberta (1999-2003). He continued his post-doctoral training at the Brain-Body Institute, McMaster University before joining the Faculty of Medicine in 2008.

Research Interests

Dr Forsythe’s research explores the neuro-immuno-endocrine super-system in the context of the holobiont, with a particular focus on identifying mechanisms underlying the influence of gut microbes, and their products on the development of diverse pathophysiological responses such as inflammation, allergic disease and mood disorders. A major focus of his work has been on obtaining an understanding of the mechanisms underlying the protective effects of gut microbes and their products in allergy and asthma. His work in this area lead to the first report that oral treatment with probiotic bacteria could attenuate major characteristics of an allergic airway response in adult mice, suggesting that it may be possible to develop microbial based therapeutic or prophylactic strategies for asthma. He further determined that induction of Foxp3+ regulatory T cells is a major determinant of the ability of certain bacteria to protect against allergic inflammation. Dr Forsythe has a strong interest in neural regulation of immunity and particular in exploring the putative microbiota-gut-brain-immune axis. In this regard, he has been investigating the role of the vagus nerve as part of the inflammatory reflex, responding to microbial cues that lead to afferent signaling to the brain with neurochemical and behavioral consequences and efferent signals that regulate immune responses. As a result of this work he was a lead author on the first demonstration that specific gut bacteria can modulate normal behavior in mice. Working with multi-disciplinary collaborators has allowed him to expand his research into the areas of neurophysiology and animal behavior.

Selected Publications

  1. Castillo-Courtade L, Han S, Lee S, Mian FM, Buck R, Forsythe P. Attenuation of food allergy symptoms following treatment with human milk oligosaccharides in a mouse model. Allergy. 2015 [Epub ahead of print]
  2. Forsythe P. Probiotics and lung immune responses. Ann Am Thorac Soc. 2014;11 S1:S33-7
  3. Forsythe P. Gut microbes as modulators of the neuro-immuno-endocrine system. PharmaNutrition, 2013;1:115–122
  4. McClemens J, Kim JJ, Wang H, Mao YK, Collins M, Kunze W, Bienenstock J, Forsythe P, Khan WI. Lactobacillus rhamnosus ingestion promotes innate host defense in an enteric parasitic infection. Clin Vaccine Immunol. 2013;20(6):818-26.
  5. Forsythe P, Kunze WA. Voices from within: gut microbes and the CNS. Cell Mol Life Sci. 2013 Jan;70(1):55-69.
  6. Karimi K, Kandiah N, Chau J, Bienenstock J, Forsythe P. A Lactobacillus rhamnosus strain induces a hemeoxygenase dependent increase in Foxp3+ regulatory T cells. PLoS One. 2012;7(10):e47556.
  7. Forsythe P, Wang B, Khambati I, Kunze WA. Systemic effects of ingested Lactobacillus rhamnosus: inhibition of mast cell membrane potassium (IKCa) current and degranulation. PLoS One. 2012;7(7):e41234.
  8. Bravo JA, Forsythe P, Chew MV, Escaravage E, Savignac HM, Dinan TG, Bienenstock J, Cryan JF. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. ProcNatlAcadSci U S A. 2011 108(38):16050-5.
  9. Forsythe P. Probiotics and lung diseases. Chest 2011; 139(4):901-8.
  10. Karimi K, Bienenstock J, Wang L, Forsythe P. The Vagus Nerve Modulates CD4+ T cell Activity. Brain Behav Immun. 2010;24(2):316-23

See PubMed for full listing

Team members

Graduate students: Lucrecia Castillo, Sehrish Zehra, Aadil Bharwani, Imtiaz Karamat