Asthma is one of the most common immune-mediated diseases affecting children and adults worldwide. Asthma is a complex condition that develops by a combination of both environmental and genetic factors. Amongst the many environmental factors that influence asthma incidence, early-life alterations to the gut microbiome are strongly associated with asthma susceptibility in children. Data from diverse population-based studies repeatedly show that factors such as birth via Caesarian (C-section), exclusive formula feeding, urban (vs. farm) living, prenatal and neonatal use of antibiotics, among others also known to directly influence the composition and function of the gut microbiome, increase the risk of children for being diagnosed with asthma by school age. The Arrieta lab aims to characterize how various environmental factors impact the microbiome and the specific microbial signatures that may predispose infants to asthma.

The gut microbiome and the brain communicate bi-directionally via several host- and microbially-derived signaling mechanisms, forming the microbiome-gut-brain axis. The hypothalamic-pituitary-adrenal (HPA) axis is the principal regulator of the stress response in the body through the release of glucocorticoids such as cortisol. The microbiome has been causally implicated in HPA axis programming in early life in rodents, however, understandings in humans remain limited. Given the gut microbiome and the brain undergo periods of significant development in parallel in early life, and the microbiome-gut-brain axis is increasingly recognized as a key mechanism by which the microbiome influences host development and health outcomes, our lab seeks to better understand this relationship through both translational and clinical studies. 

It has been previously established that the microbiome plays a crucial role in host metabolism and metabolic development. Additionally, the immune system, which has also been found to be regulated by the microbiome, has been implicated in the metabolic inflammation that accompanies obesity. While the role of bacterial commensals has been extensively investigated, the fungal population (mycobiome) remains understudied in this context. For this reason, the Arrieta lab aims to take a multi-kingdom approach to explore how commensal microbes modulate host metabolism as well as the immunological consequences of this relationship. We also plan to determine how the microbiome can be harnessed for therapeutic benefit in a metabolic context.

The Arrieta lab’s interest in the microbiome also extends past early life to the microbiome’s role in metabolism, immune function and colonization resistance. It is known that certain microbiome metabolites, such as SCFAs, can limit some pathogen’s ability to infect their hosts, and the Arrieta lab, along with some fantastic collaborators, is investigating the role of some novel microbiome-produced small aromatic molecules (MPSAMs).  The effect of these molecules on colonization resistance against and virulence factors of Salmonella and EPEC infection, as well as their role in regulating host immune and metabolic functions is currently being investigated.

A central goal of the Arrieta lab is to advance our ecological understandings of the early life gut microbiome, as this is fundamental to generating meaningful progress in health outcome-related microbiome research. The microbiome is a complex, multi-kingdom ecosystem, however, most research to date has focused only on characterizing the composition and functional role of bacteria. This provides an incomplete portrayal of the complex ecological dynamics occurring both within the gut and in relation to host physiological processes. Research from our lab has shown that bacteria and fungi are engaged in several symbiotic relationships, including in relation to immune responses, although much remains to be elucidated in understanding these interactions. The Arrieta lab continuously seeks to better characterize interkingdom dynamics occurring within the gut microbiome and understand their varied influences on the development and function of host physiological systems. 

Alberta BLOOM is an important research initiative at the University of Calgary aiming to discover how the maternal and infant microbiome impact infant and child health. The Arrieta lab leads a clinical cohort study of premature infants born in Calgary called the Alberta BLOOM Study. This study follows premature infants from birth to three years of age, collecting comprehensive biological and clinical data that enables us to examine microbiome development during this period through a number of lenses. Given colonization patterns of the premature infant gut microbiome are known to differ from term-born infants, our goal is to better understand how these early alterations may impact infant development and long-term health outcomes, and to determine whether microbiome-based therapeutics may be employed to improve health outcomes in this population.

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