Modulation of the inflammation-coagulation interaction during pneumococcal pneumonia by immunobiotic Lactobacillus rhamnosus CRL1505: role of Toll-like receptor 2

Abstract

This study evaluated the effect of nasally administered Lactobacillus rhamnosus CRL1505 on the immuno-coagulative response during pneumococcal infection in immunocompetent mice. In addition, we aimed to gain insight in the knowledge of the mechanism involved in the immunomodulatory effect of the L. rhamnosus CRL1505 strain by evaluating the role of Toll-like receptor (TLR)-2. Results showed that nasally administered L. rhamnosus CRL1505 effectively regulate inflammation and hemostatic alterations during the pneumococcal infection. Immunobiotic treatment significantly reduced permeability of the bronchoalveolar?capillarity barrier, and general cytotoxicity, decreasing lung tissue damage. The CRL1505 strain improved the production of TNF-α, IFN-γ, and IL-10 after pneumococcal challenge. In addition, increased thrombomodulin (TM) and reduced tissue factor (TF) expressions were found in lungs of L. rhamnosus CRL1505-treated mice. Moreover, we demonstrated for the first time that TLR2 signaling pathway has a role in the induction of IFN-γ and IL-10 and the reduction of TF. Results also allow us to speculate that a pattern recognition receptor (PRR), other than TLR2, may mediate the immunobiotic activity of L. rhamnosus CRL1505 and could explain changes in TNF-α and TM.