SummaryCell therapy is a promising approach to generate an enteric nervous system (ENS) and treat enteric neuropathies. However, for translation to the clinic, it is highly likely that enteric neural progenitors will require manipulation prior to transplantation to enhance their ability to migrate and generate an ENS. In this study, we examine the effects of exposure to several factors on the ability of ENS progenitors, grown as enteric neurospheres, to migrate and generate an ENS. Exposure to glial-cell-line-derived neurotrophic factor (GDNF) resulted in a 14-fold increase in neurosphere volume and a 12-fold increase in cell number. Following co-culture with embryonic gut or transplantation into the colon of postnatal mice in vivo, cells derived from GDNF-treated neurospheres showed a 2-fold increase in the distance migrated compared with controls. Our data show that the ability of enteric neurospheres to generate an ENS can be enhanced by exposure to appropriate factors.

Gastrointestinal (GI) dysfunction is a common comorbidity of Chronic Obstructive Pulmonary Disease (COPD) for which a major cause is cigarette smoking (CS). The underlying mechanisms and precise effects of CS on gut contractility, are not fully characterised. Therefore, this study aimed to investigate whether CS impacts GI function and structure in a mouse model of CS-induced COPD. We also aimed to investigate GI function in the presence of ebselen, an antioxidant that has shown beneficial effects on lung inflammation resulting from CS exposure. Mice were exposed to CS for 2 or 6 months. GI structure was analysed by histology and immunofluorescence. After 2-months of CS exposure, ex vivo gut motility was analysed using video-imaging techniques to examine changes in colonic migrating motor complexes (CMMCs). CS decreased colon length in mice. Mice exposed to CS for 2 months had a higher frequency of CMMCs and a reduced resting colonic diameter but no change in enteric neuron numbers. 10-days cessation after 2 months CS reversed CMMC frequency changes but not the reduced colonic diameter phenotype. Ebselen treatment reversed CS-induced reduction in colonic diameter. After 6 months CS, the number of myenteric nitric-oxide producing neurons was significantly reduced. This is the first evidence of colonic dysmotility in a mouse model of CS-induced COPD. Dysmotility after 2 months CS is not due to altered neuron numbers, however, prolonged CS-exposure significantly reduced enteric neuron numbers in mice. Further research is needed to assess potential therapeutic applications of ebselen in GI dysfunction in COPD.

Maternal influenza A virus (IAV) infection during pregnancy can affect offspring immune programming and development. Offspring born from influenza-infected mothers are of increased risk of neurodevelopmental disorders and have impaired respiratory mucosal immunity against pathogens. The gut-associated lymphoid tissue (GALT) represents a large proportion of the immune system in the body and plays an important role in gastrointestinal homeostasis. This includes immune modulation to antigens derived from food or microbes, gut microbiota composition, and gut-brain axis signalling. Therefore, in this study, we investigated the effect of maternal IAV infection on mucosal immunity of the GI tract in the offspring. There were no major anatomical changes to the gastrointestinal tract of offspring born to influenza-infected dams. In contrast, maternal IAV did affect mucosal immunity of offspring, showing regional differences in immune cell profiles within distinct GALT. Neutrophils, monocytes/macrophages, CD4+ and CD8+ T cells infiltration was increased in the caecal patch offspring from IAV-infected dams. In the Peyer's patches, only activated CD4+ T cells were increased in IAV offspring. IL-6 gene expression was also elevated in the caecal patch but not in the Peyer's patches of IAV offspring. These findings suggest that maternal IAV infection perturbs homeostatic mucosal immunity in the offspring gastrointestinal tract. This could have profound ramifications on the gut-brain axis and mucosal immunity in the lungs leading to increase susceptibility to respiratory infections and neurological disorders in the offspring later in life.

1AbstractEnterotoxigenic Escherichia coli (ETEC) is a leading cause of bacterial diarrhea in travelers, military personnel and children in developing countries. Infection has the potential to cause long-term gastrointestinal dysfunction. Preventative treatments for ETEC-induced diarrhea exist, yet the effects of these treatments on gastrointestinal commensals in healthy individuals is unclear. Whether administration of a prophylactic preventative treatment for ETEC-induced diarrhea causes specific shifts in gut microbial populations in controlled environments is also unknown. Here we studied the effects of a hyperimmune bovine colostrum (IMM-124E) used in the manufacture of Travelan® (AUST L 106709) on gastrointestinal bacteria in healthy C57BL/6 mice. Using next generation sequencing, we aimed to test the onset and magnitude of potential changes to the mouse gut microbiome in response to the anti-diarrheagenic hyperimmune bovine colostrum product, rich in immunoglobulins against select ETEC strains (Travelan®, Immuron Ltd). We engineered changes in mouse fecal and cecal bacterial communities by delivering lipopolysaccharide (LPS) antibodies derived from bovine colostrum via dietary supplementation. Holstein Friesian and Jersey cows between 28- and 35-weeks’ gestation stimulated by subcutaneous delivery of three important pathogenic and antigenic determinants; LPS, flagella, and colonization factor antigen (CFA), produced a hyperimmune colostrum (IMM-124E) with demonstrated beneficial effects on health via modulation of metabolic pathways and immune function. We show that in mice administered colostrum containing LPS antibodies there was an increased abundance of potentially gut-beneficial bacteria, such as Akkermansia and Desulfovibrio, without disrupting the underlying ecology of the gastrointestinal tract. Compared to controls, there was no difference in overall weight gain, body or cecal weights or small intestine length following LPS antibody colostrum supplementation. Overall, dietary supplementation with colostrum containing LPS antibodies produced subtle alterations in gut bacterial composition of mice. Primarily, Travelan® LPS antibody treatment decreased the ratio of Firmicutes/Bacteroidetes in gut microbial populations in unchallenged healthy mice. Further studies are required to examine the effect of Travelan® LPS antibody treatment to engineer the microbiome in a diseased state and during recovery.