Background: The epithelia of the intestine perform various functions,
playing a crucial role in providing a physical barrier and an innate immune
defense against infections. By generating a “three-dimensional” (3D) model of
cell co-cultures using the IPEC-J2 cell line and porcine blood monocyte-derived
macrophages (MDMs), we are getting closer to mimicking the porcine intestine
ex vivo.Methods: The effect of Limosilactobacillus
reuteri B1/1 and Limosilactobacillus fermentum CCM 7158 (indicator
strain) on the relative gene expression of interleukins (IL-1, IL-6,
IL-8, IL-18 and IL-10), genes encoding receptors for TLR4 and TLR2, tight
junction proteins such as claudin-1 (CLDN1), occludin (OCLN) and important
antimicrobial proteins such as lumican (LUM) and olfactomedin-4 (OLMF-4) was
monitored in this model. Results: The results obtained from this pilot
study point to the immunomodulatory potential of newly isolated L.
reuteri B1/1, as it was able to suppress the enhanced pro-inflammatory response
to lipopolysaccharide (LPS) challenge in both cell types. L. reuteri
B1/1 was even able to up-regulate the mRNA levels of genes encoding antimicrobial
proteins LUM and OLFM-4 and to increase tight junction (TJ)-related genes CLDN1 and
OCLN, which were significantly down-regulated in LPS-induced IPEC-J2
cells. Conversely, L. fermentum CCM 7158, chosen as an indicator lactic
acid bacteria (LAB) strain, increased the mRNA levels of the investigated
pro-inflammatory cytokines (IL-18, IL-6, and IL-1) in MDMs when LPS was
simultaneously applied to basally deposited macrophages. Although L.
fermentum CCM 7158 induced the production of pro-inflammatory cytokines,
synchronous up-regulation of the anti-inflammatory cytokine IL-10 was detected in
both LAB strains used in both cell cultures. Conclusions: The obtained
results suggest that the recently isolated LAB strain L. reuteri B1/1
has the potential to alleviate epithelial disruption caused by LPS and to
influence the production of antimicrobial molecules by enterocytes.