Lactobacillus mucosae DPC 6426 as a Bile-Modifying and Immunomodulatory Microbe

Published: 30 December 2018| Version 1 | DOI: 10.17632/phm6ztsd9t.1
Paul MacDaragh Ryan


DATA Four separate documents are contained herein. The first pertains to bile deconjugation profiling and bile salt hydrolase activity displayed by a number of Lactobacillus mucosae and Lactobacillus reuteri strains. The sheets contained within this file include "Protein Extract BSH Assay", "Bile Deconjugation by Class" and "Bile Deconjugation Complete", with the latter two containing data for both murine and porcine bile exposures. The second document contains cytokine gene expression and media concentrations of same following exposures of RAW264.7 macrophages to varying levels of exopolysaccharide (EPS) and secretome of Lactobacillus mucosae DPC 6426. Data includes IL-10, IL-6, TNF-a, CD206 and iNOS expression, as well as medium concentrations of IL-10 and NO, and cell viability assays. The third contains reactive oxygen species release results from both promyelocyte cell line and human isolated neutrophils following exposures to varying levels of EPS. The final document contains data relating to TLR reporter assays in human embryonic kidney cells following exposures to varying levels of EPS. ABSTRACT Background | Lactobacillus mucosae DPC 6426 has previously demonstrated potentially cardio-protective properties, in the form of dyslipidaemia and hypercholesterolemia correction in an apolipoprotein-E deficient mouse model. This study aims to characterise the manner in which this microbe may modulate host bile pool composition and immune response, in the context of cardiovascular disease. Lactobacillus mucosae DPC 6426 was assessed for bile salt hydrolase activity and specificity. The microbe was compared against several other enteric strains of the same species, as well as a confirmed bile salt hydrolase-active strain, Lactobacillus reuteri APC 2587. Results | Quantitative bile salt hydrolase assays revealed that enzymatic extracts from Lactobacillus reuteri APC 2587 and Lactobacillus mucosae DPC 6426 demonstrate the greatest activity in vitro. Bile acid profiling of porcine and murine bile following incubation with Lactobacillus mucosae DPC 6426 confirmed a preference for hydrolysis of glyco-conjugated bile acids. In addition, the purified exopolysaccharide and secretome of Lactobacillus mucosae DPC 6426 were investigated for immunomodulatory capabilities using RAW264.7 macrophages. Gene expression data revealed that both fractions stimulated increases in interleukin-6 and interleukin-10 gene transcription in the murine macrophages, while the entire secretome was necessary to increase CD206 transcription. Moreover, the EPS elicited a dose-dependent increase in nitric oxide and interleukin-10 production from RAW264.7 macrophages, concurrent with increased tumour necrosis factor- secretion at all doses. Conclusions | This study indicates that Lactobacillus mucosae DPC 6426 modulates both bile pool composition and immune system tone in a manner which may contribute significantly to the previously identified cardio-protective phenotype.



University College Cork BioSciences Institute


Microbiology, Immunomodulation, Bile Acid, Lactobacillus, Bile Salt