BIFIDOBACTERIUM ANIMALIS SUBSP. LACTIS INL1 CELL-FREE SUPERNATANT ATTENUATES THE INFLAMMATORY RESPONSE OF LPS-STIMULATED MACROPHAGES

CARRIERE PEDRO; NOVOA DÍAZ MARÍA BELEN; SICA GABRIELA; VINDEROLA GABRIEL; CALVO NATALIA; GENTILI CLAUDIA

Congreso; Reunión conjunta SAIC-SAB-AAFE-AACYTAL; 2023

SAIC-SAB-AAFE-AACYTAL

The inflammatory response protects the body against pathogens; however its persistence can lead to inflammatory diseases. This work aimed to explore the effect of cell-free supernatant (CFS) of the human milk-derived strain Bifidobacterium animalis subsp. lactis INL1 (B. lactis INL1) (transfer agreement UNS-UNL No REC-1092496-2) in an in vitro model of inflammation, specifically lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. To evaluate the mitochondrial integrity of these macrophages, they were pretreated with CFS for 3 hours and then exposed to LPS for 24 hours. By JC-1 assay we observed that LPS maintains mitochondrial health but it increases due CFS pretreatment followed LPS treatment (p˂0,05), suggesting that CFS from B. lactis INL1 has beneficial properties for cell physiology. Next, an in silico analysis was performed to identify the signaling pathways associated with the documented effect of the B. lactis bacteria on macrophages. Using Cytoscape software, the gene interaction network was obtained. JUN, which encodes the c-jun transcription factor involved in the inflammatory response, was found to be the core gene of the network by betweenness and closeness. Functional enrichment showed that the genes obtained are associated with the inflammatory response, the LPS response, and inflammatory bowel diseases. In addition, we analyzed gene expression data from RAW264.7 macrophage microarrays exposed or not to LPS (GSE21548-GEO). Differentially expressed genes (Log2FC≥1 or ≤-1) showed that the JUN gene was overexpressed in LPS-exposed macrophages (Log2FC=1,435; padj˂0,05). Based on these data, we study c-jun protein levels status by Western blot in our experimental model. The expression of c-jun increases by LPS action but this effect is attenuated by CFS pretreatment of B. lactis INL1 in these cells (p˂0.05), suggesting that c-jun pathway could be a potential mediator of the effects of B. lactis INL1 in the inflammatory context.