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Punicalagin (PUN) is a polyphenol derived from the pomegranate peel. It has been reported to have many beneficial effects, including anti-inflammatory, anti-oxidant, and anti-proliferation. However, the role of PUN in macrophage phagocytosis is currently unknown. In this study, we found that pre-treatment with PUN significantly enhanced phagocytosis by macrophages in a time- and dose-dependent manner in vitro. Moreover, KEGG enrichment analysis by RNA-sequencing showed that differentially expressed genes following PUN treatment were significantly enriched in phagocyte-related receptors, such as the C-type lectin receptor signaling pathway. Among the C-type lectin receptor family, Mincle (Clec4e) significantly increased at the mRNA and protein level after PUN treatment, as shown by qRT-PCR and western blotting. Small interfering RNA (siRNA) mediated knockdown of Mincle in macrophages resulted in down regulation of phagocytosis. Furthermore, western blotting showed that PUN treatment enhanced the phosphorylation of nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) in macrophages at the early stage. Mincle-mediated phagocytosis by PUN was inhibited by PDTC (a NF-κB inhibitor) and SB203580 (a p38 MAPK inhibitor). In addition, PUN pre-treatment enhanced phagocytosis by peritoneal and alveolar macrophages in vivo. After intraperitoneal injection of Escherichia coli (E. coli) , the bacterial load of peritoneal lavage fluid and peripheral blood in PUN pre-treated mice decreased significantly. Similarly, the number of bacteria in the lung tissue significantly reduced after intranasal administration of Pseudomonas aeruginosa (PAO1). Taken together, our results reveal that PUN enhances bacterial clearance in mice by activating the NF-κB and MAPK pathways and upregulating C-type lectin receptor expression to enhance phagocytosis by macrophages. [ABSTRACT FROM AUTHOR]

Multi-drug-resistant bacterial infections, which have become a global threat, lack effective treatments. The discoveries of non-antibiotics with different modes of antibacterial action, such as methylsulfonylmethane (MSM), are a promising new treatment for multi-drug-resistant pathogens. We constructed a mouse peritonitis infection model to evaluate the effects of MSM against methicillin-resistant Staphylococcus aureus (MRSA) infection. The time-kill kinetics of MSM against MRSA and the effect of MSM on the integrity of bacterial cell membrane were measured. Viability effects of MSM on THP1 cells were performed by CCK-8 cytotoxicity assay. Systematic inflammatory factor levels of mice were detected using ELISA. The immune response of peritoneal macrophages during MRSA-infection was evaluated using RNA sequencing. Gene Ontology function, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, and correlation analyses were applied to analysis RNA sequencing data. RT-qPCR, western blotting and flow cytometry were performed to analysis the gene and protein expression levels of macrophages. In in vitro experiments, MSM did not show significant killing effects on the growth of MRSA directly and did not destroy bacterial membrane integrity. MSM also displayed no significant effects on the proliferative capacity of THP1 cells. However, MSM treatment protected mice against a lethal dose MRSA-infection and decreased systemic inflammation. MSM upregulated metabolic pathway in peritoneal macrophages, especial glycolysis, during MRSA infection. MSM increased the expression of M2 markers (such as Arg1), promoted phosphorylation of STAT3 (which regulates M2 polarization), and decreased the expression of M1 markers in peritoneal macrophages. Additionally, MSM treatment increased the expression of H3K18 lactylation specific target genes, including Arg1. GNE-140, the LDHA-specific inhibitor of glycolysis, blocked the MSM-induced Arg1 expression in this disease model. MSM protects against MRSA infection through immunomodulation. MSM promotes the expression of Arg1 by lactate-H3K18la pathway to control macrophage to M2 polarization; it firstly provides therapeutic potential for drug-resistant infections and sepsis. • MSM relieves inflammation and improves mice survival rate after MRSA infection. • MSM promotes M2 polarization of peritoneal macrophages via H3K18la-Arg1 pathway. • MSM could be a potential therapeutic agent against lethal MRSA-induced sepsis. [ABSTRACT FROM AUTHOR]

Jiao Mei Gu (JMG), Cayratia albifolia C.L.Li, is a type of Dong plant widely growing in Dong autonomous counties, Hunan province, China. As a type of traditional herbal medicine, the root of JMG plant has been used to treat inflammatory-related diseases such as arthritis because of its prominent anti-inflammatory effects in Dong medicine. This work investigated the anti-inflammatory effects and mechanisms of the water extract from the root of JMG on lipopolysaccharide (LPS)-induced inflammatory models. Endotoxemia was induced in C57BL/6 mice by intraperitoneal injection of LPS (20 mg/kg), meanwhile intraperitoneal administration of safe doses of JMG. The survival curve of mice was determined. Serum inflammatory cytokines were detected by the Bio-Plex Mouse Cytokine 23-Plex Panel Kit and enzyme-linked immunosorbent assay (ELISA) at 6 h after drug treatment. Hematoxylin-eosin (HE) staining of important organs was completed at 24 h after treatment. The mechanism of inflammatory action was investigated in vitro on LPS-stimulated macrophages. Macrophage inflammation was then induced using 10 μg/mL LPS. The anti-inflammatory effect of JMG was investigated by the quantitative polymerase chain reaction (qPCR) and ELISA. The anti-inflammatory mechanism was determined using western blotting, the electrophoretic mobility shift assay, and immunocytochemistry. Finally, the antimicrobial activity of JMG was verified by survival experiments in vivo and by bacterial culture experiments in vitro. A 200 mg/kg water extract of JMG was safe for mice and had a significant protective effect on LPS-induced sepsis. Organ damage of heart, liver, lung and kidney was also significantly reduced at 24 h in the JMG group, when compared with the LPS group. The serum MIP-1α (CCL-3), MIP-1β (CCL-4), IL-1β, and TNFα cytokines were significantly decreased at 6 h in the JMG group, when compared with the LPS group. In a similar manner, 0.2μg/ml JMG significantly reduced mRNA and protein levels of MIP-1α (CCL-3), MIP-1β (CCL-4), IL-1β, and TNFα in LPS-stimulated macrophage. JMG treatment inhibited the phosphorylation of NF-κB p65 and reduced nuclear transduction, thus reducing transcriptional activity. At the same time, we showed that JMG had no protective effect on Escherichia coli -induced sepsis, as well as no antimicrobial activity. Our results showed that a water-soluble extract of JMG inhibited LPS-induced inflammation via attenuating the NF-κB signaling pathway, which provides an important rationale for the treatment of inflammation-related diseases. Image 1 [ABSTRACT FROM AUTHOR]

• FC-99 inhibits the expression of tenascin-C in macrophages in arthritis mice. • FC-99 reduces tenascin-C expression by upregulating miR-494. • FC-99 relieves macrophage inflammation via the miR-494/TN-C/NF-κB pathway. • FC-99 may be a potential therapeutic candidate for treatment of rheumatoid arthritis. The excessive production of inflammatory mediators by inflammatory cells contributes to the pathogenesis of rheumatoid arthritis. Tenascin-C (TN-C) is expressed in rheumatoid joint, and is associated with levels of inflammatory mediators. FC-99 (N1-[(4-methoxy)methyl]-4-methyl-1,2-Benzenediamine), a novel 1,2-benzenediamine derivative, was previously reported to block the prolonged expression of key rheumatoid arthritis inflammatory cytokines and relieve zymosan-induced joint inflammation. However, the specific mechanism is unknown. This study aimed to examine the effects of FC-99 on TN-C expression and inflammation and investigate its possible molecular mechanism. The results showed that FC-99 treatment reduced the high expression of TN-C in ankle joints of arthritis mice. Besides, FC-99 reduced the increased number of macrophages in arthritis mice, while did not change the number of synovioblasts. Concomitantly, expression of TN-C in synovial fibroblasts exhibited no difference between control and ZIA groups, and was not apparently altered following FC-99 treatment, while FC-99 decreased TN-C expression in macrophages both in vivo and in vitro. Meanwhile, TargetScan and luciferase assays indicated that TN-C was negatively regulated by miR-494. Transfection assay further demonstrated that FC-99 inhibited TN-C by targeting miR-494. Furthermore, the reduction of miR-494 mimic on expression of TN-C was associated with NF-κB pathway. Similarly, the down-regulation of FC-99 on TN-C was considerably decreased when NF-κB pathway was inhibited. These results indicated that FC-99 relieved macrophages inflammation via the miR-494/TN-C/NF-κB pathway, finally leading to the relief of inflammation in arthritis. The findings suggested that FC-99 might be a potential therapeutic candidate for the treatment of rheumatoid arthritis. [ABSTRACT FROM AUTHOR]