Séminaire John F Cryan

A Gut Feeling About the Brain : Microbiome as a Key Regulator of Neurodevelopment and Behaviour


The brain-gut-microbiota axis is emerging as a research area of increasing interest for those investigating the biological and physiological basis of neurodevelopmental, age-related and neurodegenerative disorders. The routes of communication between the gut and brain include the vagus nerve, the immune system, tryptophan metabolism, via the enteric nervous system or by way of microbial metabolites such as short chain fatty acids.

These mechanisms also impinge on neuroendocrine function at multiple levels. Studies in animal models have been key in delineating that neurodevelopment and the programming of an appropriate stress response is dependent on the microbiota. Developmentally, a variety of factors can impact the microbiota in early life including mode of birth delivery, antibiotic exposure, mode of nutritional provision, infection, stress as well as host genetics.  At the other extreme of life, individuals who age with considerable ill health tend to show narrowing in microbial diversity. Stress can significantly impact the microbiota-gut-brain axis at all stages across the lifespan.

Recently, the gut microbiota has been implicated in a variety of conditions including obesity, autism, schizophrenia and Parkinson’s disease. Moreover, animal models have been key in linking  the regulation of fundamental brain processes ranging from adult hippocampal neurogenesis to myelination to microglia activation by the microbiome. Finally, studies examining the translation of these effects from animals to humans are currently ongoing. Further studies will focus on understanding the mechanisms underlying such brain effects and developing nutritional and microbial-based intervention strategies.

Prof. Cryan’s current research interests include the neurobiological basis of stress-related neuropsychiatric disorders including depression, anxiety and drug dependence. Moreover, his group is also focused on understanding the interaction between brain, gut & microbiome and how it applies to stress and immune-related disorders, including irritable bowel syndrome and obesity and neurodevelopmental disorders such as autism. He is also interested in applying novel approaches to facilitate drug/siRNA delivery to the brain in vivo.

Prof. Cryan’s research group consists of 12 Postdoctoral Fellows, 14 PhD students, 2 MD students, 2 MSc Students, 3 research scientists and various visiting students from Ireland, Spain, The Netherlands, USA & Canada. It is funded by Science Foundation Ireland, the Health Research Board, Enterprise Ireland and the Irish Research Council. Moreover, Prof. Cryan receives funding as a PI on the two different EU Framework 7 Programme grants.

Selected publications

Luczynski P, Tramullas M, Viola M, Shanahan F, Clarke G, O’Mahony S, Dinan TG, Cryan JF. Microbiota regulates visceral pain in the mouse. Elife. 2017 Jun 20;6. pii: e2588

(Book 2014)Microbial Endocrinology: The Microbiota-Gut-Brain Axis in Health and Disease. Mark Lyte John F. Cryan (2014) Microbial Endocr

The microbiome regulates amygdala-dependent fear recall. Hoban AE, Stilling RM, Moloney G, Shanahan F, Dinan TG, Clarke G, Cryan JF. Mol Psychiatry. 2017 May 16.

Targeting the Microbiota-Gut-Brain Axis: Prebiotics Have Anxiolytic and Antidepressant-like Effects and Reverse the Impact of Chronic Stress in Mice. Burokas A, Arboleya S, Moloney RD, Peterson VL, Murphy K, Clarke G, Stanton C, Dinan TG, Cryan JF. Biol Psychiatry. 2017 Feb 24. pii: S0006-3223(17)30042-2.

Gut-brain axis in 2016: Brain-gut-microbiota axis – mood, metabolism and behaviour. Dinan TG, Cryan JF. Nat Rev Gastroenterol Hepatol. 2017 Feb;14(2):69-70.

Adult Hippocampal Neurogenesis Is Regulated by the Microbiome. Ogbonnaya ES, Clarke G, Shanahan F, Dinan TG, Cryan JF, O’Leary OF. Biol Psychiatry. 2015 Aug 15;78(4):e7-9.

Toll-like receptor 4 regulates chronic stress-induced visceral pain in mice. Tramullas M, Finger BC, Moloney RD, Golubeva AV, Moloney G, Dinan TG, Cryan JF. Biol Psychiatry. 2014 Aug 15;76(4):340-8. doi:

Microbiota is essential for social development in the mouse.Mol Psychiatry. 2014 Feb;19(2):146-8. doi: 10.1038/mp.2013.65. Epub 2013 May 21. Desbonnet L1, Clarke G2, Shanahan F3, Dinan TG2, Cryan JF4.