Production of oxygen-derived free radicals in phagocytes is important in preventing bacterial and fungal infections. Among free radicals, superoxide anions are a typical reactive oxygen species secreted by macrophages and neutrophils. NADPH oxidase (NOX) is a key producer of superoxide anions in these cells. β-glucans from mushrooms modulate the immune system by binding with the dectin-1 receptor on macrophages. Dectin-1 functions as a pattern recognition receptor that recognizes the pathogen-associated molecular pattern of β-glucans. During dectin-1 signaling, NOX functions in the activated macrophages to produce ROS, which are critical in antimicrobial host defense. In this study, NOX activation was measured using a lucigenin chemiluminescence assay in RAW 264.7 murine macrophages treated for 1 hour with a β-glucan fraction from Phellinus baumii (BGF; 10, 100, 500, and 1000 μg/mL) in the absence or presence of phorbol 12-myristate 13-acetate (PMA) or lipopolysaccharide (LPS). NOX was activated at BGF concentrations exceeding 10 μg/mL. BGF in the presence of PMA or LPS activated the enzyme more than treatment with PMA or LPS alone. In the presence of the NOX inhibitor diphenyleneiodonium, BGF still activated NOX. When macrophages were treated with BGF and Staphylococcus aureus, bacterial viability was reduced in a concentration-dependent manner, possibly as a result of increased phagocytosis and oxygen radical production by the activated NOX. These results demonstrate that BGF is a potent stimulator of NOX in macrophages and augments macrophage-mediated phagocytosis and NOX activity.
Matrix metalloproteinase-9 (MMP-9) has diverse roles associated with cell growth, migration, invasion, and angiogenesis. Tissue inhibitor of metalloproteinase-1 (TIMP-1) is known to inhibit MMP-9 by complexing with it at a 1:1 ratio. Suppressing MMP-9 activity through the overexpression of TIMP-1 allows for regulation of tumor growth and metastasis by blocking invasion and angiogenesis in the tumor microenvironment. We found that TIMP-1 and interleukin (IL)-23 are induced in RAW264.7 macrophage cells, a cell line established by Abelson leukemia virus transformation from the BALB/c mouse strain, in a dose-dependent pattern, at the transcriptional level by treatment with a crude polysaccharide fraction of Phellinus linteus (CPP) at a range of 10 to 1000 μg/mL. We purified CPP into 2 polysaccharide fractions, Fr-I and Fr-II, and one protein fraction, Fr-III. Among the 3 fractions, Fr-II increased TIMP-1 expression 6.8-fold compared with the control, according to quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis in the RAW264.7 culture system. On the other hand, all 3 fractions increased IL-23 expression, with the highest increase brought about by Fr-II. qRT-PCR analysis showed that Fr-I and Fr-II increased IL-17 expression in RAW264.7 cells by 13.3-fold and 19.6-fold, respectively. IL-17 expression in lung tissue was increased 2.1-fold compared with the control group, whereas that in liver tissue was unaltered by oral administration of CPP for 7 days. In a mouse model, qRT-PCR analysis showed that CPP induced liver TIMP-1 and lung IL-17 expressions 8.9-fold and 2.1-fold, respectively, without affecting MMP-9 expression. Our in vitro and in vivo data suggest that inducing TIMP-1 without altering MMP-9 expression by administering the polysaccharide fraction of Ph. linteus could be a novel antitumor or antimetastasis mechanism of polysaccharide from the medicinal mushroom Ph. linteus.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.