Lactobacillus paracasei treatment modulates mRNA expression in macrophages

Macrophage metabolic pathways show changes in response to various external stimuli. Especially, increased lipopolysaccharide, an important bacterial component and Toll-like receptor 4 agonist, can induce activity in various macrophage metabolic pathways, including energy production and biosynthesis, as well as high immune responses due to increase in differentiated M1 macrophages. In this study, we confirmed that Lactobacillus paracasei (L. paracasei) KBL382, KBL384 and KBL385, isolated from the feces of healthy Koreans, can modulate various enzymes and membrane transporters related to glycolysis or macrophage polarization including hypoxia-inducible factor 1-alpha (HIF1A), inducible nitric oxide synthase (iNOS) and arginase in stimulated macrophages at the mRNA level, using the in vitro rodent bone‐marrow‐derived macrophage (BMDM) model. All L. paracasei exhibited significant down-regulatory effects on mRNAs for glycolysis-related enzymes, including lactate dehydrogenase A, solute carrier family 2 member 1, and triosephosphate isomerase. Moreover, L. paracasei treatment could lead to significant reductions in HIF1A or iNOS mRNA, and induced arginase mRNA in the BMDM model. Therefore, further extensive studies should be performed to support the application of L. paracasei, such as in probiotics or therapeutics, in controlling abnormal immune responses related to macrophage.