Biology subjects

Barnett, J. A.

Publications and source records attributed to Barnett, J. A..

4 recordsLinked to original sources

bioRxiv2024

Bio-engineering a common probiotic to exploit colonic inflammation promotes reliable efficacy in translational models of colitis

The intricate balance between the gut microbiome and host health inspires innovations in drug development. Commensal bacteria provide a multi-targeted approach ideal for treating complex medical conditions, like inflammatory bowel disease (IBD). These bacteria are self-replicating factories with broad targets that promote balanced intestinal inflammation, mucosal barrier function, and eubiosis. Yet, the lack of superiority to gold-standard treatments and their clinical inconsistency makes most probiotics unreliable for disease treatments. Intestinal inflammation, a driving factor in many diseases, often overwhelms commensal bacteria, which lack the stress-resistance mechanisms necessary to withstand host immune defenses. To address this, we introduced a persistence platform BioPersist into E. coli Nissle 1917. We hypothesized that a bio-engineered probiotic, or genetically engineered microbial medicine (GEMM), designed to persist during inflammation would enhance probiotic bioavailability during colitis, leading to sustained therapeutic outcomes. We evaluated BioPersist in multiple translational colitis models such as in mice and pigs. BioPersist delayed the onset and reduced the severity of both chronic and acute colitis, proving more effective than 5-aminosalicylate. BioPersist thrived during inflammation promoting tolerogenic immune responses that limited infiltrating leukocyte activity and decreased TNF- from resident myeloid cells in the mesentery. The persistence feature of BioPersist allowed the probiotic to overcome the damaging inflammatory response, eliciting mucosal healing evident by the increase in microbially-derived butyric acid. Based on these preclinical results, BioPersist may be a novel therapeutic option for both human and veterinary applications that sustains efficacy during colitis. One Sentence SummaryAdding a persistence feature to a probiotic enhances its efficacy for colitis treatment, enhancing future human and veterinary therapeutic applications.

microbiology↗

bioRxiv2024

Prenatal glyphosate exposure disrupts the gut-brain axis across several generations in mice.

Glyphosate, a widely used herbicide in North America, has become prevalent in the food supply, raising concerns about potential health impacts. In this exploratory study, male and female F0 mice were exposed to glyphosate through drinking water during mating and gestation. We investigated whether prenatal exposure at dietary-relevant levels (0.01 mg/kg/day, Average American Diet, [AAD]) or the U.S. EPAs acceptable daily intake (1.75 mg/kg/day, [EPA upper limit]) altered gut, metabolic, and behavioral outcomes across two generations in mice with or without genetic susceptibility to colitis (Muc2+/- and Muc2-/-, respectively). Healthy (Muc2+/-) offspring of glyphosate-exposed mice exhibited colonic goblet cell depletion, reduced mucin-2 expression, and pro-inflammatory cytokine profiles in both F1 and F2 generations. These healthy (Muc2+/-) offspring also developed metabolic dysfunction, including impaired glucose tolerance, insulin resistance, and reduced GLP-1 in serum. Behavioral deficits were also observed in healthy (Muc+/-) mice including reduced locomotion and working memory, and these changes were associated with altered microbiome composition and gut-brain mediators. These findings suggest that prenatal glyphosate exposure, even below regulatory thresholds, may disrupt multiple physiological systems across generations, highlighting the need for further research and regulatory consideration.

pharmacology and toxicology↗

bioRxiv2021

A Mediterranean-like fat blend protects against the development of severe colitis in the mucin-2 deficient murine model

The Mediterranean diet (MD) is a health-promoting, moderate fat diet (~ 40% energy). It is not known if the blend of fats found in the MD contribute to the beneficial protective effects. We compared the MD fat blend (high monounsaturated, 2:1 n-6:n-3 polyunsaturated and moderate saturated fat) to isocaloric diets composed with corn oil (CO, n-6 polyunsaturated-rich), olive oil (high monounsaturated-rich) or milk fat (MF, saturated-rich) on spontaneous colitis development in Muc2-/- mice. The MD resulted in lower clinical and histopathological scores, and induced tolerogenic CD103+CD11b+ dendritic, Th22 and IL-17+IL-22+ cells important for intestinal barrier repair. MD also reduced attendant insulin resistance and a shift to a higher health-promoting gut microbes including Lactobacillus B. animalis and Muribaculaceae, whereas CO showed higher prevalence of mucin-degraders (Akkermansia muciniphila) and colitis promoters (Enterobacteriaceae). Our findings suggest that the MD fat blend could be recommended as a maintenance diet for colitis.

immunology↗

bioRxiv2020

Physical activity shapes the intestinal microbiome and immunity of healthy mice but has no protective effects against colitis in MUC2-/- mice

The interactions among humans, their environment, and the trillions of microbes residing within the human intestinal tract form a tripartite relationship that is fundamental to the overall health of the host. Disruptions in the delicate balance between the intestinal microbiota and their host immunity are implicated in various chronic diseases including inflammatory bowel disease (IBD). There is no known cure for IBD, therefore, novel therapeutics targeting prevention and symptoms management are of great interest. Recently, physical activity in healthy mice was shown to be protective against chemically-induced colitis, however the benefits of physical activity during or following disease onset is not known. In this study, we examine whether voluntary wheel running is protective against primary disease symptoms in a mucin 2 deficient (Muc2-/-) life-long model of murine colitis. We show that 6 weeks of wheel running in healthy C57BL/6 mice leads to distinct changes in fecal bacteriome, increased butyrate production, and modulation in colonic gene expression of various cytokines, suggesting an overall primed anti-inflammatory state. However, these physical activity-derived benefits are not present in Muc2-/- mice harboring a dysfunctional mucosal layer from birth, ultimately showing no improvements in clinical signs. We extrapolate from our findings that while physical activity in healthy individuals may be an important preventative measure against IBD, for those with a compromised intestinal mucosa, a commonality in IBD patients, these benefits are lost.

microbiology↗