BioProject

Bacteroides vulgatus is a pathobiont potentially involved with the etiology of ulcerative colitis (UC). UC is characterized by distinct changes to the community structure of the gut microbiota however relatively little is known about how the UC gut milieu might specifically impact B. vulgatus growth and functional activity, and how these changes might affect host health. To address these questions we modelled the adaptive growth response of B. vulgatus PC510 cultured in complex medium supplemented with fecal waters collected from healthy (H) and UC subjects. The specific growth rate of B. vulgatus PC510 was increased by the addition of fecal waters to the growth medium with both H or UC fecal waters resulting in a similar increase in growth rate (p<0.05); however despite this apparent similarity transcriptomic profiling revealed that 832 genes were differentially expressed. The addition of H fecal water increased the expression of genes underpinning carbohydrate metabolism including from host glycans whereas UC fecal water increased the expression of genes underpinning growth rate via anaplerotic reactions and the maximization of ATP production from monosaccharide catabolism, in addition to the detoxification of reactive oxygen species and cell adhesion. We also identified a putative NF-B immunomodulatory regulon and determined that both B. vulgatus PC510 and B. vulgatus ATCC 8482 are capable of modulating NF-B activity in a HT-29/kb-seap-25 cell culture line in a growth phase and strain specific manner. Our results suggest that the growth of B. vulgatus is sustained by distinct metabolic networks expressed in response to changes in the gut milieu between H and UC subjects. The “switch” to a colitogenic state may be part of the growth-related stress responses of the bacterium and this may provide new options to attenuate its immunomodulatory effects.