Interaction-based screening, Monte Carlo Bayesian inference-based de novo design and in vitro verification of adenine-binding peptide.

One of the main reasons for hyperuricemia is high purine intake. The primary strategy for treating hyperuricemia is blocking the purine metabolism enzyme. However, by binding the purine bases directly, we suggested a unique therapeutic strategy that might interfere with purine metabolism. There have been numerous reports of extensive interactions between proteins and purine bases. Adenine, constituting numerous protein co-factors, can interact with the adenine-binding motif. Using Bayesian Inference and Markov chain Monte Carlo sampling, we created a novel adenine-binding peptide Ile-Tyr-Val-Thr based on the structure of the adenine-binding motifs. Ile-Tyr-Val-Thr generates a semi-pocket that can clip the adenine within, as demonstrated by docking. Then, using thermodynamic techniques, the interaction between Ile-Tyr-Val-Thr and adenine was confirmed. The KD value is 1.50e-5 (ΔH = -20.2 kJ/mol and ΔG = -27.6 kJ/mol), indicating the high affinity. In brief, the adenine-binding peptide Ile-Tyr-Val-Thr may help lower uric acid level by blocking the absorption of food-derived adenine.

Comparison of 3 hyperuricemia mouse models and evaluation of food-derived anti-hyperuricemia compound with spontaneous hyperuricemia mouse model.

Hyperuricemia animal models have long been used for evaluating food-derived anti-hyperuricemia compounds. Fructose and potassium oxonate are commonly used for developing hyperuricemia mouse model. Recent research also developed spontaneous hyperuricemia model by uricase knockout (Uox-/-). In this work, we evaluated 3 kinds of models with the same gene background to illustrate the differences between the treatments. Unlike the uric acid levels in potassium oxonate (224.79 ± 33.62 µmol/L) and Uox-/- groups (458.39 ± 38.29 µmol/L), fructose treatment did not lead to higher serum uric acid level (174.93 ± 30.46 µmol/L) comparing to the control group (153.53 ± 40.96 µmol/L). However, abnormal glycometabolism only developed in the fructose and the Uox-/- group. In addition, anemia, inflammasome and severe renal injury occurred in the Uox-/- group. The Uox-/- mice were then treated with puerarin and allopurinol, and found that puerarin could reduce serum uric acid and alleviated the serious renal damage associated with high uric acid. Thus, the Uox-/- mice could be a suitable model for screening and evaluating anti-hyperuricemia compounds.

Effect on purine releasement of Lentinus edodes by different food processing techniques.

Lentinus edodes (LE) is very popular in the world and also considered as high purine food. However, few focuses on purine types and its change during food processing. Here, we first compared 3 drying techniques, including roast-drying, freeze-drying, sun-drying on purine contents of LE by using acidolysis and HPLC. It showed that adenine decreased significantly after roast-drying (120 °C), which may be caused by thermal damage of DNA. Total purine decreased significantly after freeze-drying, while roast-dried and sun-dried LE remained unchanged. The effect of moist heat (boiling) on LE purine were also evaluated. Total purine increased due to xanthine increasement (331.72 ± 50.07%). And purine contents transferred into boiled liquid was higher than that in boiled solid. Compared with sun-dry and roast-dry processing, freeze-drying could notably affect the purine release from LE and decrease purine contents. Therefore, freeze-drying is recommended for process techniques for hyperuricemia and gouts populations.

Culture and establishment of self-renewing human liver 3D organoids with high uric acid for screening antihyperuricemic functional compounds.

Hyperuricemia (HUA) is a metabolic disease caused by disorders of purine metabolism, the prevalence of which has increased worldwide. At present, most drugs aimed at lowering uric acid have toxic side effects, and in vitro screening of uric acid-lowering active substances are inefficient. Here, a long-term 3D human liver organoid culture system with high uric acid for screening and evaluating the efficacy of uric acid-lowering functional compounds. This liver organoids can be established from single hepatocytes and grown for multiple months, while retaining key morphological and functional features. Furthermore, establishment of HUA organoids model was verified by antihyperuricemic drugs allopurinol, as well as reported bioactive peptides, which significantly reduced uric acid production in the liver organoids (p < 0.05). The results demonstrated that it has the potential to be used as a rapid and valid in vitro model to screen antihyperuricemic compounds that mimics in vivo cell growth patterns.

Establishment of a 3D hyperuricemia model based on cultured human liver organoids.

Hyperuricemia (HUA) is a metabolic disorder caused by abnormal purine metabolism, the prevalence of which has increased worldwide. Here, a 3D organoid culture system for mimicking HUA in vitro was established using cultured human liver organoids. Liver organoids can be generated from single hepatocytes and passaged for several months, retaining key morphological features, functional purine metabolism and global gene expression profile. Furthermore, organoids can be differentiated into hepatocytes with high expression of maturation markers including the hepatocyte nuclear factor-4-alpha (HNF4α), E-cadherin (E-Ca), and albumin (ALB). Importantly, organoids can produce high level of uric acid after xanthine induction which is the substrate of xanthine oxidase. Furthermore, the preclinical application potential of this organoid model was verified by measuring the antihyperuricemic effect of the widely used allopurinol, as well as the reported bioactive substance puerarin. The results demonstrate that this novel organoid model could be used for high-throughput screening of both chemical and food-derived compounds with antihyperuricemic bioactivity.

Purification, Characterization, and Bioactivities of Polyphenols from Platycladus orientalis (L.) Franco.

The polyphenols (PF) from Platycladus Orientalis (L.) Franco leaves were purified by using 10 different macroporous adsorption resins. HPD-722 resin showed the best adsorption and desorption capacities. The static and dynamic adsorption and desorption of PF on HPD-722 resin were studied and the total polyphenols were separated into two fractions, PF-A and PF-B. PF-A and PF-B demonstrated similar scavenging activity of free radical (DPPH, ABTS, hydroxyl radical, superoxide anion). The scavenging activity of PF-A and PF-B on hydroxyl radical and superoxide anion radical reached the equal levels of vitamin C and gallic acid. The IC50 value of PF-A for hydroxyl radical scavenging activity and superoxide anion radical scavenging activity were 0.50 and 0.56 mg/mL, while those of PF-B were 0.61 and 0.64 mg/mL. PF-A and PF-B could reduce the overproduction of inflammatory cytokines (TNF-α, Pro-IL-1ß, and IL-6) induced by lipopolysaccharide and their protein expression in THP-1 cells. PF-B exhibited better anti-inflammatory effect than PF-A in the dosage range of 1.0-4.0 µg/mL. Structural identification of PF-A and PF-B were conducted by HPLC-MS/MS. Ten polyphenol compounds were identified in PF-A and PF-B, respectively, by HPLC-MS/MS, including quercetin, apigenin, myricetin, and so on. Molecular docking studies indicated that apigenin, myricetin, luteolin, kaempferol, and quercetin effectively inhibit xanthine oxidase by forming hydrogen bonds with the amino acid residues and binding to the active site of the enzyme. The results might supply useful information for better understanding the chemical structure, antioxidant, and anti-inflammatory activities of Platycladuso (L.) Franco leaves polyphenols. PRACTICAL APPLICATION: This study demonstrated that polyphenols from P. orientalis (L.) Franco leaves have the potential applications as functional food ingredient for the prevention and treatment of gout and inflammation, hyperuricemia and gout.