Synthesis and Biological Evaluation of Novel Chlorogenic Acid-Apigenin Conjugates as Anti-acute Gout Agents.

Gout is the second largest metabolic disease worldwide after diabetes, with acute gouty arthritis as most common symptom. Xanthine oxidase (XOD) and the NOD like receptor-3 (NLRP3) inflammasome are the key targets for acute gout treatment. Chlorogenic acid has been reported with a good anti-inflammatory activity, and Apigenin showed an excellent potential in XOD inhibition. Therefore, a series of chlorogenic acid-apigenin (CA) conjugates with varying linkers were designed and synthesized as dual XOD/NLRP3 inhibitors, and their activities both in XOD and NLRP3 inhibition were evaluated. An in vitro study of XOD inhibitory activity revealed that the majority of CA conjugates exhibited favorable XOD inhibitory activity. Particularly, the effects of compounds 10c and 10d, with an alkyl linker on the apigenin moiety, were stronger than that of allopurinol. The selected CA conjugates also demonstrated a favorable anti-inflammatory activity in RAW264.7 cells. Furthermore, compound 10d, which showed the optimal activity both in XOD inhibition and anti-inflammatory, was chosen and its inhibitory ability on NLRP3 and related proinflammatory cytokines was further tested. Compound 10d effectively reduced NLRP3 expression and the secretion of interluekin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) with an activity stronger than the positive control isoliquiritigenin (ISL). Based on these findings, compound 10d exhibits dual XOD/NLRP3 inhibitory activity and, therefore, the therapeutic effects on acute gout is worthy of further study.

The Alleviating Effect of Taxifolin on Deoxynivalenol-Induced Damage in Porcine Intestinal Epithelial Cells.

Deoxynivalenol (DON) contamination in feed is a global concern that severely threatens the health of animals and humans. Taxifolin (TA) is a natural flavonoid, a member of the polyphenols, that possesses robust antioxidant properties. This study aimed to investigate the effect of TA on DON-induced damage in porcine intestinal epithelial cells (IPEC-J2). The cells were pre-incubated with a series of concentrations of TA for 24 h and exposed to DON (0.5 µg/mL) for another 24 h. The results showed that pretreatment with TA (150 µM) significantly inhibited the DON-induced decline in cell viability (p < 0.05) and cell proliferation (p < 0.01). Additionally, 150 µM TA also alleviated DON-induced apoptosis (p < 0.01). Moreover, TA decreased the production of reactive oxygen species (ROS) induced by DON (p < 0.01). In addition, TA attenuated DON-induced cell junction damage (p < 0.05). Further experiments showed that TA reversed the DON-induced reduction in antioxidant capacity in the IPEC-J2 cells, probably via activating the Nrf2 signaling pathway (p < 0.05). Collectively, these findings suggest that 150 µM TA can protect against 0.5 µg/mL DON-induced damage to IPEC-J2 cells, potentially via the activation of the Nrf2 signaling pathway. This study provides insight into TA's potential to act as a green feed additive in the pig farming industry and its efficacy in counteracting DON-induced intestinal damage.

In vitro antibacterial effects of Broussonetia papyrifera leaf extract and its anti-colitis in DSS-treated mice.

Recently, the hybrid Broussonetia papyrifera (BP) has been extensively cultivated and predominantly utilized in ruminants because of its high protein and bioactive compound content. In the present study, the effects of an ethanolic extract of BP leaves (BPE, 200 mg/kg) on mitigating 2% dextran sodium sulfate (DSS)-induced intestinal inflammation in mice were evaluated. BPE is rich in flavonoids, polyphenols, and polysaccharides, and displays potent antioxidant and antibacterial activities against pathogenic strains such as Clostridium perfringens, Salmonella Typhimurium, and Salmonella enterica subsp. enterica in vitro. In a mouse study, oral administration of DSS resulted in weight loss, incidence of diarrhea, enlargement of the liver and spleen, impaired colonic morphology, downregulation of both gene and protein expression related to intestinal antioxidant (Nrf2) and barrier function (ZO-1), decreased diversity of colonic microbiota, and 218 differentially altered colonic metabolites; however, co-treatment with BPE did not restore these modified aspects except for the liver index and colonic bacterial diversity. The singular treatment with BPE did not manifest evident side effects in normal mice but induced a mild occurrence of diarrhea and a notable alteration in the colonic metabolite profile. Moreover, a single BPE administration augmented the abundance of the commensal beneficial bacteria Faecalibaculum and Akkermansia genera. Overall, the extract of BP leaves did not demonstrate the anticipated effectiveness in alleviating DSS-induced intestinal inflammation.

Impact of fermented Broussonetia papyrifera on laying performance, egg quality, lipid metabolism, and follicular development of laying hens.

Hybrid Broussonetia papyrifera (BP) has been widely planted and commonly used as ruminant forage source after fermentation in China. Very less information is available to know the impact of fermented BP on laying hens, thus, we have investigated effects of dietary supplementation of Lactobacillus plantarum-fermented B. papyrifera (LfBP) on laying performance, egg quality, serum biochemical parameters, lipid metabolism, and follicular development of laying hens. A total of 288 HY-Line Brown hens (age, 23 wk) were randomly assigned into 3 treatment groups: control group (Con, a basal diet), LfBP1 and LfBP5 group (a basal diet supplemented with 1% or 5% LfBP). Each group has 8 replicates of twelve birds each. The results demonstrated that dietary supplementation of LfBP increased average daily feed intake (linear, P < 0.05), feed conversion ratio (linear, P < 0.05), and average egg weight (linear, P < 0.05) during the entire experimental period. In addition, dietary inclusion of LfBP enhanced the egg yolk color (linear, P < 0.01) but decreased the eggshell weight (quadratic, P < 0.05) and eggshell thickness (linear, P < 0.01). In serum, the LfBP supplementation linearly decreased the content of total triglyceride (linear, P < 0.01) but increased the content of high density lipoprotein-cholesterol (linear, P < 0.05). The gene expression related to hepatic lipid metabolism including acetyl-CoA carboxylase, fatty acid synthase, and peroxisome proliferator-activated receptor (PPARα) was down-regulated whereas liver X receptor was up-regulated in LfBP1 group. Moreover, LfBP1 supplementation remarkably reduced the F1 follicle number and ovarian gene expression of reproductive hormone receptors including estrogen receptor, follicle stimulating hormone receptor, luteinizing hormone receptor, progesterone receptor, prolactin receptor, and B cell lymphoma-2. In conclusion, dietary inclusion of LfBP could improve feed intake, egg yolk color, and lipid metabolism, but may cause a decline in eggshell quality with higher inclusion level, herein, 1% is suggested.

Nicotinamide mononucleotide supplementation protects the intestinal function in aging mice and D-galactose induced senescent cells.

The nicotinamide adenine dinucleotide (NAD+) level shows a temporal decrease during the aging process, which has been deemed as an aging hallmark. Nicotinamide mononucleotide (NMN), a key NAD+ precursor, shows the potential to retard the age-associated functional decline in organs. In the current study, to explore whether NMN has an impact on the intestine during the aging process, the effects of NMN supplementation on the intestinal morphology, microbiota, and NAD+ content, as well as its anti-inflammatory, anti-oxidative and barrier functions were investigated in aging mice and D-galactose (D-gal) induced senescent IPEC-J2 cells. The results showed that 4 months of NMN administration had little impact on the colonic microbiota and NAD+ content in aging mice, while it significantly increased the jejunal NAD+ content and improved the jejunal structure including increasing the villus length and shortening the crypt. Moreover, NMN supplementation significantly up-regulated the mRNA expression of SIRT3, SIRT6, nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), the catalytic subunit of glutamate-cysteine ligase (GCLC), superoxide dismutase 2 (SOD2), occludin, and claudin-1, but down-regulated the mRNA expression of tumor necrosis factor alpha (TNF-α). Specifically, in the D-gal induced senescent IPEC-J2 cells, 500 µM NMN restored the increased mRNA expression of interleukin 6 (IL6ST), IL-1A, nuclear factor (NF-κB1), and claudin-1 to normal levels to some extent. Furthermore, NMN treatment significantly affected the mRNA expression of antioxidant enzymes including NQO1, GCLC, SOD 2 and 3, and GSH-PX1, 3 and 4. In addition, 200 µM NMN enhanced the cell viability and total antioxidant capacity and lowered the reactive oxygen species level of senescent IPEC-J2 cells. Notably, NMN restored the down-regulated protein expression of occludin and claudin-1 induced by D-gal. The above data demonstrated the potential of NMN in ameliorating the structural and functional decline in the intestine during aging.

Policosanol alleviates hepatic lipid accumulation by regulating bile acids metabolism in C57BL6/mice through AMPK-FXR-TGR5 cross-talk.

Policosanol exhibits a lipid accumulation alleviating effect, but the underlying mechanisms remains unclear. Bile acids are a significant factor in regulating cholesterol and lipid metabolism homeostasis in mammals. This study was aimed to elucidate the alleviating effect and underlying mechanisms of policosanol on hepatic lipid accumulation through bile acid (BA) metabolism. Policosanol supplementation significantly reduced hepatic triglycerides (19.29%), cholesterol (30.38%) in high fat diet (HFD) induced obese mice (P < 0.05). Furthermore, compared with the control group, HFD decreased the levels of total BAs (TBAs, 37.67%) and cholic acid (CA, 62.74%) in the serum of mice (P < 0.05). Meanwhile, compared to HFD group, policosanol also increased the level of secondary BAs (SBAs) and muricholic acids (MCAs, P < 0.05). qRT-PCR combined with protein level analysis revealed that policosanol significantly decreased sterol regulatory element-binding protein (SREBP-1c) and CD36, and increased the expression level of cytochrome P450 family 7 subfamily A member 1 (CYP7A1) and cytochrome P450 Family 27 Subfamily A Member 1 (CYP27A1, P < 0.05). Additionally, in the liver, policosanol was found downregulated the expression of farnesoid X receptor (FXR)-small heterodimer partner (SHP), and activate the Takeda G-coupled protein receptor 5 (TGR5)-adenosine-monophosphate-activated protein kinase (APMK) signaling pathway (P < 0.05). Peroxisome proliferator activated receptor (PPAR)-α, hormone sensitive lipase (HSL), and carnitine palmitoyltransferase (CPT)-1α also significantly increased in HP group (P < 0.05). The aforementioned results reveal that the potential mechanism of policosanol in alleviating liver lipid accumulation is to promote BA synthesis and lipolysis through regulating the cross-talk of the AMPK-FXR-TGR5. New insight for the application of policosanol as an anti-fatty liver functional food ingredient or supplement is also provided. PRACTICAL APPLICATION: Policosanol is an important active component of cereals and insect waxes (15-80%). However, almost no policosanol in refined foods such as clear corn germ oil and wheat flour. This study showed that oral administration of policosanol can significantly reduce triglyceride and cholesterol levels in the liver through affecting AMPK-TGR5-FXR cross-talk, whereas no significant toxicological effect is reported in human and mouse models. This study may provide theoretical support for the theory of dietary structure and the development of dietary supplements to improve lipid metabolism targeting the "bile acid-AMPK-TGR5" pathway.

The cytoprotective effects of dihydromyricetin and associated metabolic pathway changes on deoxynivalenol treated IPEC-J2 cells.

In this study, we investigated the cytoprotective effects of dihydromyricetin (DHM) against deoxynivalenol (DON)-induced toxicity and accompanied metabolic pathway changes in porcine jejunum epithelial cells (IPEC-J2). The cells were incubated in 250 ng/ml DON cotreated with 40 µM DHM, followed by toxicity analysis, oxidative stress reaction analysis, inflammatory response analysis and metabolomic analysis. The results showed that DHM significantly increased the cell viability (P < 0.01), the intracellular GSH level (P < 0.01) and decreased the intracellular ROS level (P < 0.01), the secretion of TNF-α, IL-8 (P < 0.01) and the apoptotic cell percentages (P < 0.01) in IPEC-J2 cells compared to that in the DON group. Metabolomic analysis revealed that DHM recovered the disorder of metabolic pathways such as glutamate metabolism, arachidonic metabolism and histidine metabolism caused by DON. In summary, DHM alleviated cell injury induced by DON and it is possibly through its antioxidant activity, anti-inflammatory activity or ability to regulate metabolic pathways.

Metabolic Profiling by UPLC-Orbitrap-MS/MS of Liver from C57BL/6 Mice with DSS-Induced Inflammatory Bowel Disease.

Liver disorder often occurs in patients with inflammatory bowel disease (IBD); however, the changes in IBD-induced liver disorder at the intrinsic molecular level (chiefly metabolites) and therapeutic targets are still poorly characterized. First, a refined and translationally relevant model of DSS chronic colitis in C57BL/6 mice was established, and cecropin A and antibiotics were used as interventions. We found that the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 in the liver tissues of mice were highly increased in the context of DSS treatment but were lowered by cecropin A and antibiotics. Subsequently, an untargeted metabolomics analysis was performed by UPLC-Orbitrap-MS/MS to reveal the metabolic profile and attempt to find the potential therapeutic targets of the liver disorders that occur in IBD. Notably, 133 metabolites were identified by an integrated database. Metabolism network and pathway analyses demonstrated that the metabolic disturbance of the liver in IBD mice was mainly enriched in bile acid metabolism, arachidonic acid metabolism, amino acid metabolism, and steroid hormone biosynthesis, while those disturbances were regulated or reversed through cecropin A and antibiotic treatment. Furthermore, the top 20 metabolites, such as glutathione, maltose, arachidonic acid, and thiamine, were screened as biomarkers via one-way analysis of variance (one-way ANOVA, p < 0.05) coupled with variable importance for project values (VIP >1) of orthogonal partial least-squares discriminant analysis (OPLS-DA), which could be upregulated or downregulated with the cecropin A and antibiotics treatment. Spearman correlation analysis showed that the majority of the biomarkers have a significant correlation with cytokines (TNF-α, IL-1ß, IL-6, and IL-10), indicating that those biomarkers may act as potential targets to interact directly or indirectly with cecropin A and antibiotics to affect liver inflammation. Collectively, our results extend the understanding of the molecular alteration of liver disorders occurring in IBD and offer an opportunity for discovering potential therapeutic targets in the IBD process.

Cecropin A Alleviates Inflammation Through Modulating the Gut Microbiota of C57BL/6 Mice With DSS-Induced IBD.

The present study is undertaken to assess the alleviating effects of antimicrobial peptide cecropin A on inflammatory bowel disease (IBD) in C57BL/6 mice and changes in the gut microbiota, compared to an antibiotic gentamicin. Different doses of cecropin A were intraperitoneally injected into C57BL/6 mice for 5 days to determine the safe doses. The injection doses at ≤ 15 mg/kg showed no negative impact on the liver, heart, spleen, and kidney. The severe and moderate IBD mice model was successfully established via supplementation of 4 or 2.5% dextran sulfate sodium (DSS) in drinking water for 5 days. The severe IBD model was used to ensure the optimal therapeutic dose of cecropin A. Survival rate, body weight and disease activity index (DAI) scores were measured. Administration of 15 mg/kg, not 5 mg/kg cecropin A, for 5 days increased survival rate and decreased body weight loss of mice. The moderate IBD model was applied to investigate the mechanisms for cecropin A to alleviate inflammation in comparison to gentamicin. The mice were treated with 15 mg/kg cecropin A or 5 mg/kg gentamicin for 3 days. The levels of cytokines and related proteins in the colon were detected by ELISA and Western blotting. The microbiota in cecum contents were analyzed using 16S rRNA gene sequencing. The results showed that cecropin A and gentamicin relieved body weight loss, DAI, and gut mucosa disruption, while decreasing tumor necrosis factor-α (TNF-α), interlukin-1ß (IL-1ß), and interlukin-6 (IL-6) induced by DSS. In addition, cecropin A and gentamicin showed different effects on the gut microbiota structure. Both cecropin A and gentamicin decreased DSS-induced enrichment of Bacteroidaceae and Enterobacteriaceae. However, cecropin A showed a selective enrichment of Lactobacillus in contrast to gentamicin, which demonstrated a selective effect on Desulfovibrionaceae and Ruminococcaceae. Cecropin A alleviates IBD through decreasing harmful gut microflora and specifically enhancing beneficial gut microflora. The mechanism of this effect is different from gentamicin.

Acute exposure to deoxynivalenol inhibits porcine enteroid activity via suppression of the Wnt/ß-catenin pathway.

The intake of food containing deoxynivalenol frequently causes damage to the intestine, the renewal of which is driven by intestinal stem cells (ISCs). Nevertheless, the toxicity of deoxynivalenol on ISCs and its underlying mechanisms remain to be elucidated. As pigs are the most sensitive animals to deoxynivalenol, we used piglets for investigation in this study. Here, we show that intestinal epithelial cell activity, B cell-specific Moloney murine leukemia virus insertion site 1 (Bmi1) protein level, and Wnt/ß-catenin pathway activity were suppressed with acute expose to deoxynivalenol. We further established a novel system for porcine crypt isolation and ex vivo cultivation. Crypts and crypt cells expanded and budded with typical enteroid morphologies under this system. Our results show that both acute in vivo and in vitro administration of deoxynivalenol significantly decreased enteroid activity. Simultaneously, protein levels of ß-catenin and leucine-rich-repeat-containing G-protein-coupled receptor 5 (Lgr5) in enteroids were reduced by deoxynivalenol exposure. In conclusion, we established a reliable culture system for porcine enteroids and demonstrated for the first time that the activity of ISCs and the Wnt/ß-catenin pathway is sensitively suppressed by acute deoxynivalenol exposure.

Cecropin A Modulates Tight Junction-Related Protein Expression and Enhances the Barrier Function of Porcine Intestinal Epithelial Cells by Suppressing the MEK/ERK Pathway.

Inflammatory bowel disease (IBD) in humans and animals is associated with bacterial infection and intestinal barrier dysfunction. Cecropin A, an antimicrobial peptide, has antibacterial activity against pathogenic bacteria. However, the effect of cecropin A on intestinal barrier function and its related mechanisms is still unclear. Here, we used porcine jejunum epithelial cells (IPEC-J2) as a model to investigate the effect and mechanism of cecropin A on intestinal barrier function. We found that cecropin A reduced Escherichia coli (E. coli) adherence to IPEC-J2 cells and downregulated mRNA expression of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and interleukin-8 (IL-8). Furthermore, cecropin A elevated the transepithelial electrical resistance (TER) value while reducing the paracellular permeability of the IPEC-J2 cell monolayer barrier. Finally, by using Western blotting, immunofluorescence and pathway-specific antagonists, we demonstrated that cecropin A increased ZO-1, claudin-1 and occludin protein expression and regulated membrane distribution and F-actin polymerization by increasing CDX2 expression. We conclude that cecropin A enhances porcine intestinal epithelial cell barrier function by downregulating the mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway. We suggest that cecropin A has the potential to replace antibiotics in the treatment of IBD due to its antibacterial activity on gram-negative bacteria and its enhancement effect on intestinal barrier function.

CDX2 Stimulates the Proliferation of Porcine Intestinal Epithelial Cells by Activating the mTORC1 and Wnt/ß-Catenin Signaling Pathways.

Caudal type homeobox 2 (CDX2) is expressed in intestinal epithelial cells and plays a role in gut development and homeostasis by regulating cell proliferation. However, whether CDX2 cooperates with the mammalian target of rapamycin complex 1 (mTORC1) and Wnt/ß-catenin signaling pathways to stimulate cell proliferation remains unknown. The objective of this study was to investigate the effect of CDX2 on the proliferation of porcine jejunum epithelial cells (IPEC-J2) and the correlation between CDX2, the mTORC1 and Wnt/ß-catenin signaling pathways. CDX2 overexpression and knockdown cell culture models were established to explore the regulation of CDX2 on both pathways. Pathway-specific antagonists were used to verify the effects. The results showed that CDX2 overexpression increased IPEC-J2 cell proliferation and activated both the mTORC1 and Wnt/ß-catenin pathways, and that CDX2 knockdown decreased cell proliferation and inhibited both pathways. Furthermore, the mTORC1 and Wnt/ß-catenin pathway-specific antagonist rapamycin and XAV939 (3,5,7,8-tetrahydro-2-[4-(trifluoromethyl)]-4H -thiopyrano[4,3-d]pyrimidin-4-one) both suppressed the proliferation of IPEC-J2 cells overexpressing CDX2, and that the combination of rapamycin and XAV939 had an additive effect. Regardless of whether the cells were treated with rapamycin or XAV939 alone or in combination, both mTORC1 and Wnt/ß-catenin pathways were down-regulated, accompanied by a decrease in CDX2 expression. Taken together, our data indicate that CDX2 stimulates porcine intestinal epithelial cell proliferation by activating the mTORC1 and Wnt/ß-catenin signaling pathways.

CDX2 increases SLC7A7 expression and proliferation of pig intestinal epithelial cells.

Nutrient absorption mediated by nutrient transporters expressed in the intestinal epithelium supplies substrates to support intestinal processes, including epithelial cell proliferation. We evaluated the role of Caudal type homeobox 2 (CDX2), an intestine-specific transcription factor, in the proliferation of pig intestinal epithelial cells (IPEC-1) and searched for novel intestinal nutrient transporter genes activated by CDX2. Our cloned pig CDX2 cDNA contains a "homeobox" DNA binding motif, suggesting it is a transcriptional activator. CDX2 overexpression in IPEC-1 cells increased cell proliferation, the percentage of cells in S/G2 phase, and the abundance of transcripts of the cell cycle-related genes Cyclin A2; Cyclin B; Cyclin D2; proliferating cell nuclear antigen; and cell cycle cyclin-dependent kinases 1, 2 and 4, as well as the predicted CDX2 target genes SLC1A1, SLC5A1 and SLC7A7. In addition, luciferase reporter and chromatin immunoprecipitation assays revealed that CDX2 binds directly to the SLC7A7 promoter. This is the first report of CDX2 function in pig intestinal epithelial cells and identifies SLC7A7 as a novel CDX2 target gene. Our findings show that nutrient transporters are activated during CDX2-induced proliferation of normal intestinal epithelial cells.