title: Microbiota/host crosstalk biomarkers: regulatory response of human intestinal dendritic cells exposed to Lactobacillus extracellular encrypted peptide.
abstract: The human gastrointestinal tract is exposed to a huge variety of microorganisms, either commensal or pathogenic; at this site, a balance between immunity and immune tolerance is required. Intestinal dendritic cells (DCs) control the mechanisms of immune response/tolerance in the gut. In this paper we have identified a peptide (STp) secreted by Lactobacillus plantarum, characterized by the abundance of serine and threonine residues within its sequence. STp is encoded in one of the main extracellular proteins produced by such species, which includes some probiotic strains, and lacks cleavage sites for the major intestinal proteases. When studied in vitro, STp expanded the ongoing production of regulatory IL-10 in human intestinal DCs from healthy controls. STp-primed DC induced an immunoregulatory cytokine profile and skin-homing profile on stimulated T-cells. Our data suggest that some of the molecular dialogue between intestinal bacteria and DCs may be mediated by immunomodulatory peptides, encoded in larger extracellular proteins, secreted by commensal bacteria. These peptides may be used for the development of nutraceutical products for patients with IBD. In addition, this kind of peptides seem to be absent in the gut of inflammatory bowel disease patients, suggesting a potential role as biomarker of gut homeostasis.
authors.affiliation: Antigen Presentation Research Group, Imperial College London, Harrow, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Bernardo
authors.forename: Borja
authors.initials: B
authors.lastname: Sánchez
authors.forename: Hafid O
authors.initials: HO
authors.lastname: Al-Hassi
authors.forename: Elizabeth R
authors.initials: ER
authors.lastname: Mann
authors.forename: María C
authors.initials: MC
authors.lastname: Urdaci
authors.forename: Stella C
authors.initials: SC
authors.lastname: Knight
authors.forename: Abelardo
authors.initials: A
authors.lastname: Margolles
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D015415:Biomarkers; D004269:DNA, Bacterial / Q000235:genetics; D003713:Dendritic Cells / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance; D066298:In Vitro Techniques; D015212:Inflammatory Bowel Diseases / Q000276:immunology / Q000382:microbiology; D007422:Intestines / Q000166:cytology / Q000276:immunology*; D048191:Lactiplantibacillus plantarum / Q000235:genetics / Q000276:immunology*; D054892:Metagenome / Q000276:immunology; D008969:Molecular Sequence Data; D019936:Probiotics
chemical_list: D001426:Bacterial Proteins; D015415:Biomarkers; D004269:DNA, Bacterial