Lacticaseibacillus rhamnosus postbiotic-induce beneficial on emergency myelopoiesis in mielosuppressed mice

VASILE, BRENDA; GUTIÉRREZ, FLORENCIA; IVIR, MAXIMILIANO; ALVAREZ, SUSANA; SALVA, SUSANA

Mar del Plata

Congreso; Reunión Anual de Sociedades de Biociencias; 2022

Sociedad Argentina de Inmunología

Currently, there has been a great increase in the number of immunocompromised patients for various reasons. Respiratory infections are the most frequent in patients with immunodeficiencies, especially those undergoing chemotherapy. The availability of safe immunopotentiating agents is necessary to improve immunity against respiratory pathogens. In this work we studied the effect of oral administration of Lacticaseibacillus rhamnosus CRL1505 (Lr) and its cell wall (CW) on the emergency myelopoiesis against Streptococcus pneumoniae (Sp). Adult Swiss-mice were orally treated with Lr or CW during 16 consecutive days. On day 6, treated and untreated mice received one intraperitoneal dose of cyclophosphamide (Cy-150mg/kg). On day 9, mice were infected with Sp (107 UFC/mice). Innate and myelopoietic responses were evaluated after the pneumococcal challenge. The Cy group showed a high susceptibility to pneumococcal infection, an impaired innate immune response in lung and a decrease of LSK cells (Lin-Sca1+cKit+), multipotent common myeloid progenitor (CMPs, Lin-Sca1+cKit+CD34+), granulocyte-monocyte progenitors (GMPs, Lin-Sca1+cKit-CD34+), and a low expression of CXCR4 and CD62L Gr1+Ly6G+Ly6C- cells in bone marrow (BM). However, Lr and CW treatments were effective to significantly increase lung neutrophils and macrophages, blood neutrophils and peroxidase+ cells and allow an early myeloid precursor recovery in BM with respect to the Cy group. This, in turn, led to an early Sp lung clearance compared with the Cy group. Besides, the treatment with CW was more effective than Lr to decrease retention signals in the BM cells. In conclusion, the postbiotic obtained from L. rhamnosus CRL1505 induced a more efficient local innate immune response. This could be related to the modulation of chemokines responsible for stimulating an adequate emergency myelopoietic response in BM against pathogens