Glycyrol Relieves Ulcerative Colitis by Promoting the Fusion of ZO-1 with the Cell Membrane through the Enteric Glial Cells GDNF/RET Pathway.

The damage to the mechanical barrier of the intestinal mucosa is the initiating factor and the core link of the progression of ulcerative colitis (UC). Protecting the mechanical barrier of the intestinal mucosa is of great significance for improving the health status of UC patients. ZO-1 is a key scaffold protein of the mechanical barrier of the intestinal mucosa, and its fusion with the membrane of the intestinal epithelium is a necessary condition to maintain the integrity of the mechanical barrier of the intestinal mucosa. Enteric glial cells (EGCs) play an important role in the maintenance of intestinal homeostasis and have become a new target for regulating intestinal health in recent years. In this study, we found that glycyrol (GC), a representative coumarin compound isolated from Licorice (Glycyrrhiza uralensis Fisch, used for medicine and food), can alleviate UC by promoting the production of neurotrophic factor GDNF in mice EGCs. Specifically, we demonstrated that GC promotes the production of GDNF, then activates its receptor RET, promotes ZO-1 fusion with cell membranes, and protects the intestinal mucosal mechanical barrier. The results of this study can provide new ideas for the prevention and treatment of UC.

Lycopene attenuates D-galactose-induced cognitive decline by enhancing mitochondrial function and improving insulin signaling in the brains of female CD-1 mice.

The incidence of neurodegenerative diseases is severely increasing with ageing. Lycopene (LYC), a carotenoid pigment, has been reported to have antioxidant, anti-inflammatory and neuroprotective properties. In the present study, we aimed to investigate the ameliorative effect of LYC on D-galactose (D-gal) induced cognitive defects and the underlying mechanisms. Forty-five female CD-1 mice (2 months old) were separated into three groups to be fed with either a normal diet or a LYC diet (0.03%, w/w, mixed into normal diet). Meanwhile, the mice were treated by intraperitoneal injection of normal saline or D-gal 150 mg/kg/day for 8 weeks. The behavioral test results indicated that LYC alleviated D-gal induced cognitive impairments. LYC ameliorated brain ageing by decreasing the number of SA-ß-gal- stained neurons, downregulating the protein expression of the cellular senescence associated genes P19/P21/P53, increasing the activities of the antioxidant enzymes GSH and SOD, downregulating the level of ROS, inhibiting the activation of MAPKs signaling and downregulating the levels of the inflammatory cytokines IL-1ß and TNFɑ in mouse brains. LYC ameliorated synaptic dysfunction by increasing the expression of the neurotrophic factor BDNF and synaptic proteins. Moreover, LYC attenuated D-gal-induced mitochondrial morphological damage, and promoted the expression of mitochondrial functional proteins. LYC also promoted insulin signal transduction in mouse brains through the regulation of IRS-1/AKT/GSK3ß signaling.

Trimethylamine N-oxide exacerbates acetaminophen-induced liver injury by interfering with macrophage-mediated liver regeneration.

Acetaminophen (APAP)-induced acute liver injury (AILI) is the most frequent cause of acute liver failure in developed countries. Trimethylamine N-oxide (TMAO) is a metabolite derived from the gut microbiota and is relatively high in the circulation of the elderly, individuals with diabetes, and heart disease. Herein, we showed that TMAO exacerbates APAP hepatotoxicity. It is possible that delayed liver repair and regeneration that resulted from reduced macrophage accumulation was responsible for this combined hepatotoxicity. Moreover, matrix metalloproteinase 12 (Mmp12), expressed predominantly by macrophages, were reduced by TMAO in vitro and in vivo. This led to the inhibition of macrophage migration and a subsequent decrease in the recruitment of proresolving macrophages to the necrosis area. Furthermore, the administration of recombinant Mmp12 mitigated the enhanced hepatotoxicity in mice cotreated with TMAO and APAP. Overall, this study indicates that TMAO exacerbates APAP-induced hepatotoxicity by hindering macrophage-mediated liver repair, which might stem from the inhibition of Mmp12. These findings imply that liver damage in patients with high levels of circulating TMAO may be more severe in AILI and should exercise caution when treating with NAC.

PD-L1 positively regulates MET phosphorylation through inhibiting PTP1B.

Increasing bodies of evidence support the involvement of tumor-intrinsic action in PD-L1-mediated cancer progression. However, the mechanisms underlying the tumor-intrinsic function of PD-L1 are less well understood. In the present study, we found a positive correlation between PD-L1 expression and MET phosphorylation in lung cancer and melanoma cell lines. PD-L1 inhibition led to a decrease in MET phosphorylation, while PD-L1 induction by IFN-γ resulted in a PD-L1-dependent increase of MET phosphorylation both in vitro and in vivo. The results indicated that MET phosphorylation can be positively regulated by PD-L1. Furthermore, we identified PTP1B as a mediator contributing to the regulation of MET phosphorylation by PD-L1. In agreement with the induction of MET phosphorylation by PD-L1, inhibition of PD-L1 caused reduced phosphorylation of ERKs, a known downstream kinase of MET, and inhibited cell proliferation. Collectively, the present study demonstrated for the first time that the MET pathway, as a downstream of PD-L1, contributed to its tumor-intrinsic effect, and provided a novel mechanistic explanation for the tumor-intrinsic function of PD-L1 and a rationale for the combination of immunotherapy and MET-targeted therapy in cancer treatment.

Synergistic anti-colon cancer effect of glycyrol and butyrate is associated with the enhanced activation of caspase-3 and structural features of glycyrol.

Coumarin-based anti-cancer agents have attracted considerable attention recently. Butyrate, a major short-chain fatty acid produced in colon by gut microbiota, has been shown to exert anticancer activity both in vitro and in vivo. In this study, we evaluated the anti-cancer effect of combining glycyrol (GC), a representative of coumarin compounds in licorice, or its analogues Glycycoumarin/Demethylsuberosin/Coumestrol (GCM/De/Coum) with butyrate in HT29 and HCT116 cells, and explored the relationship between the combined anti-cancer effect and structural features of coumarin compounds. Results showed the strongest inhibitory effect on cancer cells was induced by GC/butyrate combination via enhanced activation of caspase-3. Our data indicated the benzofuranyl, isopentenyl and methoxy groups presented in GC played critical role in its anti-cancer activity, while the furan group led to the further enhancement. The findings of the present study will be beneficial for developing coumarin-based compounds and coumarin compound-based regimen to fight against colon cancer.

Targeting the COX2/MET/TOPK signaling axis induces apoptosis in gefitinib-resistant NSCLC cells.

MET overactivation is one of the crucial reasons for tyrosine kinase inhibitor (TKI) resistance, but the mechanisms are not wholly clear. Here, COX2, TOPK, and MET expression were examined in EGFR-activating mutated NSCLC by immunohistochemical (IHC) analysis. The relationship between COX2, TOPK, and MET was explored in vitro and ex vivo. In addition, the inhibition of HCC827GR cell growth by combining COX2 inhibitor (celecoxib), TOPK inhibitor (pantoprazole), and gefitinib was verified ex vivo and in vivo. We found that COX2 and TOPK were highly expressed in EGFR-activating mutated NSCLC and the progression-free survival (PFS) of triple-positive (COX2, MET, and TOPK) patients was shorter than that of triple-negative patients. Then, we observed that the COX2-TXA2 signaling pathway modulated MET through AP-1, resulting in an inhibition of apoptosis in gefitinib-resistant cells. Moreover, we demonstrated that MET could phosphorylate TOPK at Tyr74 and then prevent apoptosis in gefitinib-resistant cells. In line with these findings, the combination of celecoxib, pantoprazole, and gefitinib could induce apoptosis in gefitinib-resistant cells and inhibit tumor growth ex vivo and in vivo. Our work reveals a novel COX2/MET/TOPK signaling axis that can prevent apoptosis in gefitinib-resistant cells and suggests that a triple combination of FDA-approved drugs would provide a low-cost and practical strategy to overcome gefitinib resistance.

Combination of Patulin and Chlorpyrifos Synergistically Induces Hepatotoxicity via Inhibition of Catalase Activity and Generation of Reactive Oxygen Species.

Patulin (PAT) is the most common food-borne mycotoxin found in fruits and fruit-derived products, while chlorpyrifos (CPF) is a widely used pesticide on fruit and other crops. On the basis of the residue data, certain types of fruits can be contaminated simultaneously by patulin and chlorpyrifos. However, there are no available data about the combined toxicity. Since liver is a possible toxic target of both patulin and chlorpyrifos, we tested whether the combination exposure can cause enhanced hepatotoxicity using both cell culture and animal models. Results showed that the combination resulted in synergistic cytotoxicity in vitro and significantly enhanced liver toxicity in vivo. Mechanistically, PAT inhibited catalase activity via PIG3 induction, while CPF decreased catalase expression. These two mechanisms were converged in response to the combination, leading to enhanced inactivating catalase and boosted reactive oxygen species generation. The finding implicated that it is necessary to consider the combined toxicity in safety assessment of these food-borne contaminants.

Inorganic Selenium Induces Nonapoptotic Programmed Cell Death in PC-3 Prostate Cancer Cells Associated with Inhibition of Glycolysis.

Previous studies have shown that selenite, a representative of inorganic form selenium, exerts its anticancer effect by inducing apoptosis in androgen-dependent LNCaP prostate cancer cells, but few studies have determined the nature of cell death induced by selenite in metastatic androgen-refractory PC-3 cells. Our study showed that necrosis-like cell death rather than apoptosis, pyroptosis, or autophagic cell death was caused by selenite in PC-3 cells. Mechanistically, this type of cell death was caused by ATP depletion (26.28 ± 3.39 nmol/mg of control versus 9.12 ± 2.44 nmol/mg of 10 µM selenite treatment) that resulted from phosphofructokinase activity reduction (100.17 ± 0.17% of control versus 21.74 ± 6.65% of 10 µM selenite treatment). Our study also showed that ROS production is necessary for the decrease in cellular ATP levels and in phosphofructokinase activity. To our knowledge, this is the first study showing that selenite can induce necrosis-like cell death in PC-3 cells. Our findings support selenite as an effective compound for the therapy of apoptosis-resistant prostate cancer.

Glycyrol exerts potent therapeutic effect on lung cancer via directly inactivating T-LAK cell-originated protein kinase.

Molecular targeted therapy for non-small cell lung cancer (NSCLC) has demonstrated promising outcomes. T-lymphokine-activated killer cell-originated protein kinase (TOPK) is found overexpressed in many cancer types such as NSCLC, and is considered to be an effective target for lung cancer treatment. In the present study, we found that glycyrol (GC), a representative coumarin compound isolated from licorice, was highly effective against several human NSCLC cell lines in vitro, and significantly suppressed tumor growth in vivo. Mechanistically, we demonstrated that GC can strongly bind to the TOPK protein and inhibited its kinase activity, leading to the activation of apoptotic signaling pathways. The findings of the present study suggest that GC is a novel promising TOPK inhibitor and this compound deserves to be further investigated for its potential anti-NSCLC activity.

The functional role of Bax/Bak in palmitate-induced lipoapoptosis.

Induction of programmed cell death, mainly apoptosis (lipoapoptosis) is a major cellular consequence of the lipotoxicity, a harmful effect resulting from the overload of lipids. Both Endoplasmic reticulum (ER) stress and autophagy have been suggested to play important role in the regulation of lipoapoptosis. However, the exact mechanisms underlying lipoapoptosis remain unclear. In the present study, we aimed to investigate the functional role of Bax/Bak in lipoapoptosis using mouse embryonic fibroblasts (MEFs) cell culture model. Results showed that palmitate induced caspase-dependent apoptosis in wild-type Bax/Bak MEF cells, whereas a caspase-independent cell death was induced by palmitate in Bax/Bak knockout MEF cells, suggesting requirement of Bax/Bak in palmitate-induced caspase activation. More importantly, we found that the status of Bax/Bak is a determinant that governs the decision between the pro-survival or pro-death function of autophagy in response to palmitate exposure, and Bax/Bak is required for palmitate-induced activation of endoplasmic reticulum (ER) stress and subsequently ER stress-mediated apoptosis. The findings of the present study provided novel insights into understanding the mechanisms involved in the regulation of palmitate-induced lipoapoptosis.

Glycycoumarin protects mice against acetaminophen-induced liver injury predominantly via activating sustained autophagy.

BACKGROUND AND PURPOSE: Acetaminophen-induced acute liver injury (AILI) is the most frequent cause of acute liver failure in developed countries. Given the significant limitations associated with N-acetyl cysteine, the only antidote used to treat AILI, the development of novel therapeutic approaches that can offer a wide range of therapeutic time-windows is clearly needed. Glycycoumarin (GCM), a natural coumarin purified from liquorice, has been previously demonstrated to possess potent hepatoprotective effects. In the present study, we aimed to investigate the therapeutic potential of GCM against AILI. EXPERIMENTAL APPROACH: Acetaminophen (300 mg·kg-1 ) was administered to male C57BL/6 mice, with and without GCM. Serum transaminases, haematoxylin and eosin staining and Western blot were used to assess hepatic damage. KEY RESULTS: GCM (50 mg·kg-1 ) was highly effective against acetaminophen-induced hepatotoxicity. Moreover, GCM was superior to N-acetyl cysteine, in terms of the dosage and the therapeutic time-windows. Further mechanistic investigations revealed that the therapeutic action of GCM was not a result of inhibition of acetaminophen metabolic activation or associated with Nrf2. Instead, the protective effect of GCM appeared to be predominantly dependent on sustained activation of autophagy, which attenuated acetaminophen-induced mitochondrial oxidative stress and JNK activation. CONCLUSIONS AND IMPLICATIONS: Collectively, our results indicate that GCM alleviated acetaminophen-induced oxidative stress through activating autophagy, thereby protecting against AILI. Our findings suggest that GCM has potential as a novel therapeutic agent for treating AILI.

Dietary squid ink polysaccharide could enhance SIgA secretion in chemotherapeutic mice.

Secretory immunoglobulin A (SIgA) is a non-inflammatory antibody that shields internal body surfaces, such as in the intestine to neutralize pathogens in the lumen of the intestine. As chemotherapy seriously damages the mucosal immune system, we herein demonstrated that polysaccharide from the squid ink of Ommastrephes bartrami (OBP) activated intestinal SIgA secretion to prevent chemotherapeutic injury. Using a mouse model of chemotherapy induced intestinal injury by intraperitoneal injection of 50 mg kg(-1) cyclophosphamide, our results showed an enhanced SIgA concentration in intestinal mucosa by OBP administration and the higher production of SIgA relied on the greater expression of IgA, J chain and pIgR. Furthermore, the higher expressions of IL-6, IL-10 and TNF-α increased by OBP treatment contributed to enhanced IgA and J chain synthesis in IgA(+) plasma cells, and pIgR expression in epithelial cells. It also triggered a prompt immunoglobulin secretory pathway confirmed by enhanced UPR (unfolded protein response) effectors XBP-1s and Bip expression. Our results have important implications for the mucosal immunity enhancement effects of OBP as a functional food component for chemotherapeutic patients.

Dietary squid ink polysaccharides ameliorated the intestinal microflora dysfunction in mice undergoing chemotherapy.

Gastrointestinal mucositis and infection by chemotherapy treatment are associated with alteration of intestinal microflora and bacterial translocation due to the potential damage induced by anti-cancer drugs on the intestinal barrier and microbiota homeostasis. This study aimed to investigate the protective effect of dietary polysaccharides on chemotherapy induced intestinal microflora dysfunction. In the current contribution, with a mouse model intraperitoneally injected with 50 mg kg(-1) of cyclophosphamide (Cy) for 2 days, we revealed that polysaccharides from the ink of Ommastrephes bartrami (OBP) altered the intestinal microflora composition. OBP retarded the excessive growth of intestinal bacteria induced by cyclophosphamide, based on 16S rRNA gene (16S rDNA) quantification. The clone libraries of intestinal bacteria 16S rDNA were used to decipher the difference in bacterial community structures in different groups of mice. Followed by RFLP evaluation and OTU abundance analysis, they imply that OBP changed the intestinal microflora composition, in which the quantity of probiotic Bifidobacterium got up-regulated but Bacteroidetes decreased in mice undergoing chemotherapy. Our results may have important implications for OBP as a functional food component or nutrient against chemotherapy induced intestinal injury and potential pathogenic intestinal disorders involving inflammation and infection.