Tissue Inhibitor of Metalloproteinase-1 (TIMP-1) and IL-23 Induced by Polysaccharide of the Black Hoof Medicinal Mushroom, Phellinus linteus (Agaricomycetes).

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.