Extracellular proteins of Lactobacillus acidophilus DSM 20079 downregulates pro-inflammatory mediators in IBD patients

Trabajo presentado en el IX Workshop de la Sociedad Española de Probióticos y Prebióticos (SEPyP), celebrado en Zaragoza (España) el 15 y 16 de febrero de 2018[Introduction] Bifidobacteria and lactobacilli include both probiotic strains and representative microorganisms of the human gut microbiota, and their presence has been associated to a proper immune development and maturation. In addition, several independent works report the anti-inflammatory properties of several strains of those groups. However, we are far from understanding the molecular interplay behind/supporting these beneficial interactions. [Objective] To study the effect of different fractions of lactobacilli and bifidobacteria in human peripheral blood mononuclear cells (PBMCs) isolated from healthy donors and patients with Inflammatory Bowel Disease (IBD) at the time of diagnosis. [Methods] The fractions were obtained from strains of Bifidobacterium longum NCIMB 8809, Lactobacillus rhamnosus GG and Lactobacillus acidophilus DSM 20079: DNA, surface-associated proteins, whole cell soluble extract and extracellular proteins. Different concentrations of the fractions were incubated with PBMCs, and key T-cell cytokines, T regulatory cell differentiation and RNASeq of CD4+ cells were performed. [Results] Among the extracts, extracellular proteins from L. acidophilus DSM 20079 increased IL-2 production by PBMCs isolated from healthy donors, and were able to increment the proportion of functional T regulatory cells. Data on the signaling mechanisms involved were obtained by RNASeq of CD4+ Th cell subpopulations. Finally, this fraction decreased drastically the production of the pro-inflammatory mediator TNF-alpha and induced increments of IL-12 in PBMCs isolated from IBD patients at the diagnosis. [Conclusions] Extracellular proteins from strain L. acidophilus DSM 20079 had a positive impact on the immunological status of both healthy donors and IBD patients. This fraction will be on the basis of new clinical studies focused in the immunomodulation of the human host targeting pro-inflammatory effectors and the T-cell regulatory response. This fraction may represent a new therapeutic approach for chronic inflammatory illnesses. [Competing interests] Borja Sánchez and Claudio Hidalgo are members of the scientific committee of Microviable Therapeutics SL.Peer reviewe