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Lactobacillus rhamnosus GG (LGG) is increasingly applied in functional food products and acts as a probiotic model in nutritious and clinical studies. Increasing evidences have revealed the immune modulation of LGG on macrophages. The aim of this study is to investigate the effect of LGG on macrophage polarization of murine bone marrow-derived macrophages (BMDMs). BMDMs were treated with 10 8 colony-forming units (CFU)/ml LGG for 1.5, 3, and 6 hr. Results showed that LGG obviously upregulated the mRNA expression of M1-associated cytokines (p < .05), including interleukin-1 beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α), and inducible nitric oxide synthase (iNOS), whereas had no effect on the expression of M2-associated markers (p > .05), including arginase 1 (Arg1), mannose receptor, and chitinase-like protein 3 (YM1). Furthermore, LGG markedly increased the expression of pro-inflammatory cytokines (IL-12p40, cyclooxygenase-2 [COX-2], and interferon-γ [IFN-γ]) (p < .05) and anti-inflammatory cytokines (IL-10, IL-4, and transforming growth factor-β [TGF-β]) (p < .05). In addition, we also found that TLR2/MyD88/MAPK signaling pathway was required for LGG-induced M1 macrophage polarization and M1-related cytokines expression. Together, these findings demonstrate that probiotic LGG facilitates M1 polarization of BMDMs, suggesting that LGG may have an immunotherapeutic potential in regulating the host defense against pathogen invasion., (© 2020 Japanese Society of Animal Science.)

Bacillus amyloliquefaciens SC06 (BaSC06), a potential probiotic, plays a positive role in animal growth performance and immune function. The aim of the present study was to investigate the protective effect of BaSC06 against Salmonella infection and its association with macrophage polarization. C57BL/6 mice were fed with or without a BaSC06-containing diet before Salmonella enterica Typhimurium (ST) challenge. Results showed that BaSC06 had a protective effect against ST inoculation and induced both M1 and M2 macrophage polarization in the cecum. An in vitro co-culture model demonstrated that BaSC06 promoted M1 polarization directly, and thus increased the phagocytosis and bactericidal activity against ST. In addition, adoptive transfer of bone marrow-derived macrophages (BMDMs) stimulated by BaSC06 significantly decreased the counts of ST in the spleen. Furthermore, 16S rRNA-based analysis of cecal content showed that BaSC06 significantly increased the proportion of Verrucomicrobia and decreased Bacterodetes. Transplantation of the fecal microbiota from BaSC06-treated animals promoted M2 macrophage polarization in the cecum and significantly relieved inflammation caused by ST. In conclusion, BaSC06 polarized macrophages to the M1 type directly resulting in excellent bactericidal activity. Meanwhile, the microbiota modified by BaSC06 can induce M2 polarization which ameliorates the inflammation caused by ST.

Echinacea purpurea is an indigenous North American purple cone flower used by North Americans for treatment of various infectious diseases and wounds. This study investigated the effect of polysaccharide enriched extract of Echinacea purpurea (EE) on the polarization of macrophages. The results showed that 100 µg/mL of EE could markedly activate the macrophage by increasing the expression of CD80, CD86, and MHCII molecules. Meanwhile, EE upregulated the markers of classically activated macrophages (M1) such as CCR7 and the production of IL-1β, IL-6, IL-12p70, TNF-αand NO. The functional tests showed that EE enhanced the phagocytic and intracellular bactericidal activity of macrophage against ST. Furthermore, we demonstrated that JNK are required for EE-induced NO and M1-related cytokines production. Together, these results demonstrated that EE can polarize macrophages towards M1 phenotype, which is dependent on the JNK signaling pathways. J. Cell. Biochem. 118: 2664-2671, 2017. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

The roots and rhizomes of Glycyrrhiza species (licorice) have been widely used as natural sweeteners and herbal medicines. The aim of this study is to investigate the effect of glycyrrhizic acid (GA) from licorice on macrophage polarization. Both phenotypic and functional activities of murine bone marrow-derived macrophages (BMDMs) treated by GA were assessed. Our results showed that GA obviously increased the cell surface expression of CD80, CD86, and MHCII molecules. Meanwhile, GA upregulated the expression of CCR7 and the production of TNF-α, IL-12, IL-6, and NO (the markers of classically activated (M1) macrophages), whereas it downregulated the expression of MR, Ym1, and Arg1 (the markers of alternatively activated (M2) macrophage). The functional tests showed that GA dramatically enhanced the uptake of FITC-dextran and E. coli K88 by BMDMs and decreased the intracellular survival of E. coli K88 and S. typhimurium. Moreover, we demonstrated that JNK and NF-κB activation are required for GA-induced NO and M1-related cytokines production, while ERK1/2 pathway exhibits a regulatory effect via induction of IL-10. Together, these findings indicated that GA promoted polarization of M1 macrophages and enhanced its phagocytosis and bactericidal capacity. The results expanded our knowledge about the role of GA in macrophage polarization.

Pidotimod is a synthetic dipeptide with biological and immunological activity in innate immune responses. It has been reported that pidotimod could promote functional maturation of dendritic cells, but little is known about the regulation of macrophages. Recent studies have demonstrated that M1 or M2 polarized macrophages are of great importance for responses to microorganism infection or host mediators. The aim of this study was to determine the effectiveness of pidotimod on mouse bone marrow-derived macrophage polarization and its function. The results showed that pidotimod had no influence on M1-polarized macrophage. While interestingly, a significant increase of M2 marker gene expression (Arg1, Fizz1, Ym1, MR) was observed (p < 0.01) in IL-4-induced M2 macrophage treated with pidotimod. In addition, cell surface expression of mannose receptor was dramatically enhanced using fluorescence activated cell sorter (FACS) analysis. Furthermore, the function of M2 macrophage was also determinated. The results showed that the supernatant of pidotimod-treated M2 macrophage could increase the migration (p < 0.05) and enhance the wound closure rate (p < 0.05) of MLE-12 cells. Collectively, it could be concluded that pidotimod significantly facilitated IL-4-induced M2 macrophage polarization and improves its function.

To investigate the immunomodulatory effects of Bacillus subtilis (B. subtilis) (natto) B4 spores on murine macrophage, RAW 264.7 cells were cultured alone or with B subtilis (natto) B4 spores at 37°C for 12 hrs, then both cells and culture supernatants were collected for analyses. Exposure of RAW 264.7 cells to B. subtilis (natto) B4 spores had no significant effects on macrophage viability and amounts of extracellular lactate dehydrogenase (LDH). However, it remarkably increased the activities of acid phosphatase (ACP), lactate dehydrogenase (LDH) and inducible nitric oxide synthase (iNOS) in cells and the amounts of nitric oxide (NO) and cytokines (tumor necrosis factor-alpha, interferon-gamma, interleukin [IL]-1 beta, IL-6, IL-12, IL-10 and macrophage inflammatory protein-2) in culture supernatants. These results demonstrate that B. subtilis (natto) B4 spores are harmless to murine macrophages and can stimulate their activation through up-regulation of ACP and LDH activities and enhance their immune function by increasing iNOS activity and stimulating NO and cytokine production. The above findings suggest that B. subtilis (natto) B4 spores have immunomodulatory effects on macrophages., (© 2012 The Societies and Wiley Publishing Asia Pty Ltd.)

Reuterin is well-known for its broad-spectrum antimicrobial ability, while the other potential bioactivity is not yet clear. The present study aims to investigate the immunomodulatory activity of reuterin on chicken macrophage HD11 cells for the first time and evaluate whether reuterin is able to regulate the lipopolysaccharide-stimulated inflammatory response. The results showed that the safe medication range of reuterin was less than 250 μM. Reuterin treatment for 6 h decreased the transcriptional of CD86, IL-1β and iNOS and increased the expression of CD206 in a dose-dependent way, but reuterin treatment for 12 h contrary increased the expression of IL-1β, IL-6 and IL-10. However, it was noticed that reuterin treatment for 12 h significantly decreased the production of reactive oxygen species (ROS) and suppressed the phagocytosis activity of HD11 macrophages against bacteria. Further, the results showed that preincubation or coincubation with reuterin significantly attenuated the promotive effects of lipopolysaccharide (LPS) on transcription of proinflammatory cytokines (including IL-1β, IL-6 and TNF-α) and obviously inhibited nitric oxide (NO) production as well as the protein expression of inducible nitric oxide synthase (iNOS). Meanwhile, Mechanism studies implied that reuterin might exert an anti-inflammatory effect on LPS-stimulated cells by downregulating the expression of TLR4/MyD88/TRAF6 and blocking the activation of NF-κB as well as MAPKs signaling pathways. Additionally, it was found that both pretreatment and cotreatment with reuterin remarkably inhibited the oxidative stress induced by LPS stimulation by activating the Nrf2/HO-1 signaling pathway and enhancing the activities of antioxidative enzymes. These findings suggested the immunoregulatory function of reuterin and indicated this bacterial metabolite was able to inhibit the inflammation and oxidative stress of HD11 macrophages once exposed to LPS stimulation. [ABSTRACT FROM AUTHOR]

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Probiotic is a preparation containing microorganisms that confers beneficial effect to the host. This work assessed whether oral administration of Bacillus amyloliquefaciens SC06 (Ba) could decrease bacterial translocation in weaned mice. Weaned C57BL/6 were randomly allocated into three groups: group I as the control group, group II were treated with 0.85 % NaCl. Group III was administered with probiotic Ba 1 × 10 CFU/day dissolved in 100 μl of 0.85 % NaCl for 30 days. Mice were then sacrificed, and tissue were cultured to determine bacterial translocation. Meanwhile, splenic CD4T cells, CD8T cells, B cells, and macrophages were analysised by FACS. Our results showed that probiotic Ba significantly reduced bacteria translocation compared with the control group and 0.85 % NaCl group ( P < 0.05), lower levels of bacteria were detected in the MLN, liver, spleen, and kidney of mice. Moreover, significant increase in percentage and number of macrophages were observed in the spleen of Ba-treated mice compared with the control and 0.85 % NaCl groups. Together, these data indicated that Ba could decrease bacterial translocation in weaned mice. This effect seems to be correlated with the changes of macrophage numbers. [ABSTRACT FROM AUTHOR]