Caffeic acid phenethyl ester alleviated hypouricemia in hyperuricemic mice through inhibiting XOD and up-regulating OAT3.

BACKGROUND: Hyperuricemia is characterized with high serum uric acids (SUAs) and directly causes suffering gout. Caffeic acid phenethyl ester (CAPE) is widely included in dietary plants and especially propolis of honey hives. HYPOTHESIS/PURPOSE: Since CAPE exerts a property resembling a redox shuttle, the hypothesis is that it may suppress xanthine oxidase (XOD) and alleviate hyperuricemia. The aim is to unveil the hypouricemic effect of CAPE and the underlying mechanisms. METHODS: By establishing a hyperuricemic model with potassium oxonate (PO) and hypoxanthine (HX) together, we investigated the hypouricecmic effect of CAPE. On this model, the expressions of key mRNAs and proteins, including glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1), and the activity of XOD were assayed in vivo. Also, the inhibitory effect of CAPE against XOD was assayed in vitro through enzymatic activity tests and by molecular docking. RESULTS: CAPE demonstrated a remarkable hypouricemic effect, which reduced the SUAs of hyperuricemic mice (401 ± 111 µmol/l) to 209 ± 56, 204 ± 65 and 154 ± 40 µmol/l (p < 0.01) at the doses of 15, 30 and 60 mg/kg respectively, depicting efficacies between 48 and 62% and approaching allopurinol's efficacy (52%). Serum parameters, body weights, inner organ coefficients, and H&E staining suggested that CAPE displayed no general toxicity and it alleviated the liver and kidney injuries caused by hyperuricemia. Mechanistically, CAPE decreased XOD activities significantly in vivo, presented an IC50 at 214.57 µM in vitro and depicted a favorable binding to XOD in molecular simulation, indicating that inhibiting XOD may be an underlying mechanism of CAPE against hyperuricemia. CAPE did decreased GLUT9 protein and down-regulated URAT1 mRNA and protein. In addition, CAPE up-regulated ATP binding cassette subfamily G member 2 (ABCG2) and organic anion transporter 3 (OAT3) mRNA and proteins in comparison with that of the hyperuricemic control. All above, CAPE may alleviate hyperuricmia through inhibiting XOD, decreasing GLUT9 and URAT1 and increasing ABCG2 and OAT3. CONCLUSION: CAPE presented potent hypouricemic effect in hyperuricemic mice through inhibiting XOD activity and up-regulating OAT3. CAPE may be a promising treatment against hyperuricemia.

Polysaccharide from Pycnoporus sanguineus ameliorates dextran sulfate sodium-induced colitis via helper T cells repertoire modulation and autophagy suppression.

Inflammatory bowel disease (IBD) is a chronic autoimmune disease associated with various risk factors. Pycnoporus sanguineus (L.) Murrill is a saprotrophic fungus used worldwide for its industrial and medical purposes. Here, polysaccharide from P. sanguineus (PPS) was explored for its antiinflammatory potential in a murine colitis model of IBD induced by dextran sulfate sodium (DSS). PPS ameliorated the colitis as manifested by the lowered disease activity index (DAI), prolonged colon, and reduced serum lipopolysaccharide (LPS). PPS recovered the histological lesion by upregulating the expressions of Zonula occludens-1 (ZO-1), E-cadherin, and proliferating cell nuclear antigen (PCNA). PPS inhibited the helper T cells (Th)-mediated immune response by decreasing the proportions of Th cells (including Th2 cells, Th17 cells, and regulatory T cells), which was accompanied with reductions on myeloperoxidase (MPO) activity and releases of several interleukins and chemokines within the colon. Moreover, PPS exhibited an evident inhibition on autophagy, in which the ratio of light chain 3 (LC3) II/I was declined, while the expression of p62 and Beclin-1 was increased. The present study highlighted important clinical implications for the treatment application of PPS against IBD, which relies on the regulation of Th cells repertoire and autophagy suppression to restore epithelium barrier.