The gut microbiota-aromatic hydrocarbon receptor (AhR) axis mediates the anticolitic effect of polyphenol-rich extracts from Sanghuangporus.

Inflammatory bowel disease (IBD) is a significant global health concern. The gut microbiota plays an essential role in the onset and development of IBD. Sanghuangporus (SH), a traditional Chinese medicinal mushroom, has excellent anti-inflammatory effects and is effective at modulating the gut microbiota. Despite these attributes, the specific anticolitic effects of SH and the mechanisms through which the gut microbiota mediates its benefits remain unclear. Herein, we demonstrated that polyphenol-rich extract from SH effectively alleviated the pathological symptoms of dextran sodium sulfate (DSS)-induced colitis in mice by modulating the gut microbiota. Treatment with SH distinctly enriched Alistipes, especially Alistipes onderdonkii, and its metabolite 5-hydroxyindole-3-acetic acid (5HIAA). Oral gavage of live A. onderdonkii or 5HIAA potently mitigated DSS-induced colitis in mice. Moreover, both 5HIAA and SH significantly activated the aromatic hydrocarbon receptor (AhR), and the administration of an AhR antagonist abrogated their protective effects against colitis. These results underscore the potent efficacy of SH in diminishing DSS-induced colitis through the promotion of A. onderdonkii and 5HIAA, ultimately activating AhR signaling. This study unveils potential avenues for developing therapeutic strategies for colitis based on the interplay between SH and the gut microbiota.

Protocatechualdehyde Induces S-Phase Arrest and Apoptosis by Stimulating the p27(KIP1)-Cyclin A/D1-CDK2 and Mitochondrial Apoptotic Pathways in HT-29 Cells.

Protocatechualdehyde (PCA) extracted from Phellinus gilvus exhibits anti-cancer activity in human colorectal carcinoma cells (HT-29). However, the underlying mechanisms remain poorly understood. We performed an in vitro study involving MTT, flow cytometry, RT-PCR, and western blot analyses to investigate the effects of PCA treatment on cell proliferation, cell cycle distribution, apoptosis, and expression of several cell cycle-related genes in HT-29 cells. The treatment enhanced S-phase cell cycle and apoptosis in HT-29 cells in a dose-dependent manner. Western blot results showed that PCA treatment decreased the expression levels of cyclin A, cyclin D1, and p27(KIP1) but increased those of cyclin-dependent kinase 2 (CDK2) in HT-29 cells. Furthermore, the expression levels of B-cell lymphoma/leukemia-2 (Bcl-2) and B-cell lymphoma/leukemia-xL (Bcl-xL) were down-regulated, whereas the levels of BH3-interacting domain death agonist (Bid), Bcl-2 homologous antagonist/killer (Bak), and cytosolic cytochrome c were significantly upregulated. Thus, the enzymes caspases-9, -3, -8, and -6 were found to be activated in HT-29 cells with PCA treatment. These results indicate that PCA-induced S-phase cell cycle arrest and apoptosis involve p27(KIP1)-mediated activation of the cyclin-A/D1-Cdk2 signaling pathway and the mitochondrial apoptotic pathway.

Polysaccharide from Phellinus linteus induces S-phase arrest in HepG2 cells by decreasing calreticulin expression and activating the P27kip1-cyclin A/D1/E-CDK2 pathway.

ETHNOPHARMACOLOGY RELEVANCE: Our previous study showed that the proteoglycan P1 from Phellinus linteus (Mesima) exhibits significant anti-tumor activity against human hepatocellular carcinoma cells (HepG2); however, its molecular mechanism remains unknown. This study aims to provide insights into the mechanism of the anti-tumor activity of P1 against HepG2 cells. METHODS: We examined the effects of P1 on HepG2 cell proliferation in vitro and in vivo. Flow cytometry was used to analyze the cell cycle distribution and apoptosis. Proteomic analysis, real-time (RT)-PCR, and Western blot were carried out to observe the expression of several cell cycle control proteins in HepG2 cells. RESULTS: Both the volume and the weight of solid tumors were significantly decreased in P1-treated mice (200mg/kg) compared with the control. The HepG2 cells in the P1-treated tumors were significantly decreased, irregularly shaped, and smaller. P1 slightly increased the body weight of the tumor-bearing mice, which indicates that P1 is nontoxic to mammals at 200mg/kg. P1 also caused a significant dose-dependent increase in S phase arrest, but no apoptosis was observed in HepG2 cells. The results of the proteomic analysis, RT-PCR, and Western blot analysis showed that significantly downregulated expression of calreticulin, cyclin D1, cyclin E, and CDK2 and upregulated expression of P27 kip1 and cyclin A in the P1-treated HepG2 cells (200 µg/ml). CONCLUSION: These results suggest that calreticulin expression and the P27 kip1-cyclin A/D1/E-CDK2 pathway were involved in P1-induced S-phase cell cycle arrest in HepG2 cells.

Activation of P27kip1-cyclin D1/E-CDK2 pathway by polysaccharide from Phellinus linteus leads to S-phase arrest in HT-29 cells.

Our previous study showed that polysaccharide (P1) from Phellinus linteus exhibits a significant inhibitive activity on human colorectal carcinoma cells (HT-29). However its novel molecular mechanism remains unknown. To obtain insights into P1's mechanism of action, we examined its effects on cell proliferation in vitro and in vivo, cell cycle distribution, apoptosis, autophagy, and expression of several cell cycle interrelated proteins in HT-29 cells. Interestingly, we found that volume and weight of the solid tumor significantly decreased in P1 (200mg/kg)-treated mice compared with the control. However, slightly increased the body weight of the P1 treated tumor-bearing mice, with no significant increased ALT, AST levels in serum and LPO concentration in liver and kidney indicated that P1 has no toxicity to mammals at a dose of 200mg/kg. Furthermore, P1 caused a significantly dose-dependent increase in the S-phase cell cycle, but no apoptosis and autophagy in HT-29 cells. RT-PCR and Western blot results showed significantly down-regulated expressions of cyclin D1, cyclin E, and CDK2, as well as increased expressions of P27kip1 in P1 (100 µg/mL)-treated HT-29 cells. These results suggested that the activation of P27kip1-cyclin D1/E-CDK2 pathway is involved in P1-induced S-phase cell cycle arrest in HT-29 cells.

1-deoxynojirimycin inhibits glucose absorption and accelerates glucose metabolism in streptozotocin-induced diabetic mice.

We investigated the role of 1-deoxynojirimycin (DNJ) on glucose absorption and metabolism in normal and diabetic mice. Oral and intravenous glucose tolerance tests and labeled (13)C6-glucose uptake assays suggested that DNJ inhibited intestinal glucose absorption in intestine. We also showed that DNJ down-regulated intestinal SGLT1, Na(+)/K(+)-ATP and GLUT2 mRNA and protein expression. Pretreatment with DNJ (50 mg/kg) increased the activity, mRNA and protein levels of hepatic glycolysis enzymes (GK, PFK, PK, PDE1) and decreased the expression of gluconeogenesis enzymes (PEPCK, G-6-Pase). Assays of protein expression in hepatic cells and in vitro tests with purified enzymes indicated that the increased activity of glucose glycolysis enzymes was resulted from the relative increase in protein expression, rather than from direct enzyme activation. These results suggest that DNJ inhibits intestinal glucose absorption and accelerates hepatic glucose metabolism by directly regulating the expression of proteins involved in glucose transport systems, glycolysis and gluconeogenesis enzymes.

Anti-tumor effects of proteoglycan from Phellinus linteus by immunomodulating and inhibiting Reg IV/EGFR/Akt signaling pathway in colorectal carcinoma.

Proteoglycan (P1) purified from Phellinus linteus has been reported to have anti-disease activities. The objectives of our research were to determine the anti-tumor effect and possible mechanisms of P1 on human cancer cells. Cell inhibition assay showed that P1 has an antiproliferative effect on HepG2, HT-29, NCI-H 460 and MCF-7 human colon cancer cells, especially it was very effective in inhibiting HT-29 cells. When HT-29-bearing mice were treated with P1(100mg/kg), there was relative increase in spleen and thymus weights, the plasmatic pIgR and IgA levels were significantly increased, also there was a notable decrease in plasmatic PGE2, Reg IV, EGFR and Akt concentrations measured by ELISA. RT-PCR analysis suggested that P1-induced HT-29 apoptosis appeared to be associated with a decrease in the levels of expression of Reg IV and EGFR. These results suggest that P1 might have two potential roles in treating cancer; it acts as an immunopotentiator partly through protecting T cells from escaping PGE2 attack and enhancing the mucosal IgA response, and as a direct inhibitor by disrupting the Reg IV/EGFR/Akt signaling pathway.

Protective effect of sericin peptide against alcohol-induced gastric injury in mice.

BACKGROUND: Sericin peptide (SP) has shown a powerful anti-oxidant property in a host of studies. The present study was designed to investigate the possible protective effects of SP against alcohol-induced gastric lesions in mice and to explore the potential mechanisms. METHODS: Animals were randomly divided into 5 groups: control, alcohol (56%, 14.2 ml/kg), SP-treated mice (0.2, 0.4, 0.8 g/kg). Mice were pretreated with SP before administering alcohol, the concentration of ethanol in serum and urine, the contents of malondialdehyde (MDA), glutathione (GSH) and the glutathione peroxidase (GSH-PX), catalase (CAT) and superoxide dismutase (SOD) activities in the gastric mucosa were measured, subsequently, the pathological evaluation of stomach was also observed. RESULTS: Of the animals pre-treated with SP (0.4, 0.8 g/kg), the concentration of ethanol in serum was significantly decreased, while increased in urine as compared to the alcohol-administered alone animals. Alcohol administration caused severe gastric damage as indicated by markedly increased MDA levels and decreased antioxidants, such as reduced GSH, GSH-PX and SOD in the gastric tissue while the CAT activity was not altered. On SP administration there was a reversal in these values towards normal. Histopathological studies confirmed the beneficial role of SP, which was in accordance with the biochemical parameters. CONCLUSIONS: SP could protect gastric mucosa from alcohol-induced mucosal injury. These gastroprotective effects might be due to increasing 'first-pass metabolism' in the stomach and hastening ethanol elimination directly through the urine. SP might also play an important role in the protection of the structure and function of gastric mitochondria, at least partly based on their anti-oxidant effect.

[Protective effect of panax japonics on ethanol-induced mice gastric lesion].

OBJECTIVE: To study the protective effects of Panax japonics (PJ) on alcohol-induced gastric lesion in mice and the possible mechanisms. METHOD: Male ICR mice were randomized into six groups: normal, control, PJ (1.5, 3.0, 6.0 g x kg(-1)) and Yinduoan (1.5 g x kg(-1)). The mice were pretreated with PJ before administering ethanol to observe the effect on the concentration of ethanol in serum and urine. The contents of MDA, GSH and GSH-PX, CAT and SOD activities were measured in serum and gastric mucosa, and subsequently, the pathological evaluation of stomach was also observed. RESULT: The concentration of ethanol in serum was evidently decreased after PJ (1.5, 3.0 g x kg(-1)) was administrated because the ethanol was eliminated fleetly through urine. Synchronously the PJ reduced the content of MDA and increased the GSH increased in serum and gastric, besides, it increased the enzymatic activities of GSHPX, CAT and SOD, and the ethanol-induced gastric mitochondria structure injury were ameliorated so as to make the function to normal. CONCLUSION: Based on these observations, one could conclude that the PJ is a potent protective agent against ethanol-induced gastric damages. One mechanism may be related with inhibiting the absorbability of ethanol at gastrointestinal tract, decreasing the concentration of ethanol in serum, and accelerating the ethanol elimination through urine so as to alleviate the ethanol-induced damage to gastrointestinal mucosal, enhancing the first-pass metabolism in stomach, and particularly increasing the antioxidant levels in serum and gastric. These gastroprotective effects might be, at least partly, through ameliorating the gastric mitochondria structure.