Effect and Potential Mechanism of Lactobacillus plantarum Q7 on Hyperuricemia in vitro and in vivo

A comprehensive review on recent xanthine oxidase inhibitors of dietary based bioactive substances for the treatment of hyperuricemia and gout: Molecular mechanisms and perspective

Hyperuricemia (HUA) has attained a considerable global health concern, related to the development of other metabolic syndromes. Xanthine oxidase (XO), the main enzyme that catalyzes xanthine and hypoxanthine into uric acid (UA), is a key target for drug development against HUA and gout. Available XO inhibitors are effective, but they come with side effects. Recent, research has identified new XO inhibitors from dietary sources such as flavonoids, phenolic acids, stilbenes, alkaloids, polysaccharides, and polypeptides, effectively reducing UA levels. Structural activity studies revealed that -OH groups and their substitutions on the benzene ring of flavonoids, polyphenols, and stilbenes, cyclic rings in alkaloids, and the helical structure of polysaccharides are crucial for XO inhibition. Polypeptide molecular weight, amino acid sequence, hydrophobicity, and binding mode, also play a significant role in XO inhibition. Molecular docking studies show these bioactive components prevent UA formation by interacting with XO substrates via hydrophobic, hydrogen bonds, and π-π interactions. This review explores the potential bioactive substances from dietary resources with XO inhibitory, and UA lowering potentials detailing the molecular mechanisms involved. It also discusses strategies for designing XO inhibitors and assisting pharmaceutical companies in developing safe and effective treatments for HUA and gout.

Isolation and identification of uric acid-dependent Aciduricibacillus chroicocephali gen. nov., sp. nov. from seagull feces and implications for hyperuricemia treatment

Hyperuricemia has become the second most prevalent metabolic disease after diabetes, but the limitations of urate-lowering treatment (ULT) drugs and patient nonadherence make ULT far less successful. Thus, more ULT approaches urgently need to be explored. Uric acid-degrading bacteria have potential application value in ULT. In this study, we isolated 44XBT, a uric acid-degrading bacterium, from black-headed gull (Chroicocephalus ridibundus) feces. Using a polyphasic taxonomic approach, strain 44XBT was identified as a novel genus within the family Bacillaceae; subsequently, the name Aciduricibacillus chroicocephali was proposed. Strain 44XBT had a unique uric acid-dependent phenotype and utilized uric acid and allantoin as the sole carbon and nitrogen sources, but not common carbon sources or complex media. In the genome, multiple copies of genes involved in uric acid metabolic pathway (pucL, pucM, uraD, and allB) were found. Six copies of pucL (encoding urate oxidase) were detected. Of these, five pucL copies were in a tandem arrangement and shared 70.42%-99.70% amino acid identity. In vivo experiments revealed that 44XBT reduced serum uric acid levels and attenuated kidney damage in hyperuricemic mice through uric acid catalysis in the gut and gut microbiota remodeling. In conclusion, our findings discover a strain for studying bacterial uric acid metabolism and may provide valuable insights into ULT.

IMPORTANCE

The increasing disease burden of hyperuricemia highlights the need for new therapeutic drugs and treatment strategies. Our study describes the developmental and application values of natural uric acid-degrading bacteria found in the gut of birds and broadened the source of bacteria with potential therapeutic value. Furthermore, the special physiology characteristics and genomic features of strain 44XBT are valuable for further study.

Understanding Hyperuricemia: Pathogenesis, Potential Therapeutic Role of Bioactive Peptides, and Assessing Bioactive Peptide Advantages and Challenges

Hyperuricemia is a medical condition characterized by an elevated level of serum uric acid, closely associated with other metabolic disorders, and its global incidence rate is increasing. Increased synthesis or decreased excretion of uric acid can lead to hyperuricemia. Protein peptides from various food sources have demonstrated potential in treating hyperuricemia, including marine organisms, ovalbumin, milk, nuts, rice, legumes, mushrooms, and protein-rich processing by-products. Through in vitro experiments and the establishment of cell or animal models, it has been proven that these peptides exhibit anti-hyperuricemia biological activities by inhibiting xanthine oxidase activity, downregulating key enzymes in purine metabolism, regulating the expression level of uric acid transporters, and restoring the composition of the intestinal flora. Protein peptides derived from food offer advantages such as a wide range of sources, significant therapeutic benefits, and minimal adverse effects. However, they also face challenges in terms of commercialization. The findings of this review contribute to a better understanding of hyperuricemia and peptides with hyperuricemia-alleviating activity. Furthermore, they provide a theoretical reference for developing new functional foods suitable for individuals with hyperuricemia.

Biodegradation of Uric Acid by Bacillus paramycoides-YC02

High serum uric acid levels, known as hyperuricemia (HUA), are associated with an increased risk of developing gout, chronic kidney disease, cardiovascular disease, diabetes, and other metabolic syndromes. In this study, a promising bacterial strain capable of biodegrading uric acid (UA) was successfully isolated from Baijiu cellar mud using UA as the sole carbon and energy source. The bacterial strain was identified as Bacillus paramycoides-YC02 through 16S rDNA sequence analysis. Under optimal culture conditions at an initial pH of 7.0 and 38 °C, YC02 completely biodegraded an initial UA concentration of 500 mg/L within 48 h. Furthermore, cell-free extracts of YC02 were found to catalyze and remove UA. These results demonstrate the strong biodegradation ability of YC02 toward UA. To gain further insight into the mechanisms underlying UA biodegradation by YC02, the draft genome of YC02 was sequenced using Illumina HiSeq. Subsequent analysis revealed the presence of gene1779 and gene2008, which encode for riboflavin kinase, flavin mononucleotide adenylyl transferase, and flavin adenine dinucleotide (FAD)-dependent urate hydroxylase. This annotation was based on GO or the KEEG database. These enzymes play a crucial role in the metabolism pathway, converting vitamin B2 to FAD and subsequently converting UA to 5-hydroxyisourate (HIU) with the assistance of FAD. Notably, HIU undergoes a slow non-enzymatic breakdown into 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) and (S)-allantoin. The findings of this study provide valuable insights into the metabolism pathway of UA biodegradation by B. paramycoides-YC02 and offer a potential avenue for the development of bacterioactive drugs against HUA and gout.

Lactobacillus fermentum F40-4 ameliorates hyperuricemia by modulating the gut microbiota and alleviating inflammation in mice

Hyperuricemia (HUA) is a systemic disease characterized by a disorder of purine metabolism and an abnormal increase in the serum level of uric acid (UA). Probiotics can exert potential therapeutic benefits against some metabolic diseases by regulating the intestinal microbiota. Lactobacillus fermentum F40-4 with UA-lowering activity of 87.40% was screened using purine as the target in vitro. The UA-lowering activity of L. fermentum F40-4 was further explored in a mouse model of HUA in vivo. L. fermentum F40-4 could downregulate serum levels of UA, blood urea nitrogen, creatinine, and xanthine oxidase by 40.84%, 11.61%, 57.66%, and 41.79%, respectively. L. fermentum F40-4 restored organ damage, and adjusted enzyme activity and transporter expression to promote the metabolic level of UA. In addition, L. fermentum F40-4 could reshape the gut microbiota and suppress inflammation to ameliorate HUA. An increment in intestinal UA excretion was documented. These findings suggest that L. fermentum F40-4 might serve as a potential probiotic for the prevention and treatment of HUA.

Ameliorative Effect of Mannuronate Oligosaccharides on Hyperuricemic Mice via Promoting Uric Acid Excretion and Modulating Gut Microbiota

Mannuronate oligosaccharide (MOS) is α-D-mannuronic acid polymer with 1,4-glycosidic linkages that possesses beneficial biological properties. The aim of this study was to investigate the hypouricemic effect of MOS in hyperuricemic mice and demonstrate the possible protective mechanisms involved. In this research, 200 mg/kg/day of MOS was orally administered to hyperuricemic mice for four weeks. The results showed that the MOS treatment significantly reduced the serum uric acid (SUA) level from 176.4 ± 7.9 μmol/L to 135.7 ± 10.9 μmol/L (p < 0.05). MOS alleviated the inflammatory response in the kidney. Moreover, MOS promoted uric acid excretion by regulating the protein levels of renal GLUT9, URAT1 and intestinal GLUT9, ABCG2. MOS modulated the gut microbiota in hyperuricemic mice and decreased the levels of Tyzzerella. In addition, research using antibiotic-induced pseudo-sterile mice demonstrated that the gut microbiota played a crucial role in reducing elevated serum uric acid of MOS in mice. In conclusion, MOS may be a potential candidate for alleviating HUA symptoms and regulating gut microbiota.

Probiotics, bioactive compounds and dietary patterns for the effective management of hyperuricemia: a review

Hyperuricemia is closely linked with an increased risk of developing hypertension, diabetes, renal failure and other metabolic syndromes. Probiotics, bioactive compounds and dietary patterns are safe cost-efficient ways to control hyperuricemia, whereas comprehensive reviews of their anti-hyperuricemic mechanisms are limited. This review summarizes the roles of probiotics, bioactive compounds and dietary patterns in treating hyperuricemia and critically reviews the possible mechanisms by which these interventions exert their activities. The dietary patterns are closely related to the occurrence of hyperuricemia through the indirect action of gut microbiota or the direct effects of host purine metabolism. The Mediterranean and Dietary Approaches to Stop Hypertension diets help reduce serum uric acid concentrations and thus prevent hyperuricemia. Meanwhile, probiotics alleviate hyperuricemia by ways of absorbing purine, restoring gut microbiota dysbiosis and inhibiting xanthine oxidase (XO) activity. Bioactive compounds such as polyphenols, peptides and alkaloids exert various anti-hyperuricemic effects, by regulating urate transporters, blocking the active sites of XO and inhibiting the toll-like receptor 4/nuclear factor kappa B signaling pathway and NOD-, LRR- and pyrin domain-containing protein 3 signaling pathway. This review will assist people with hyperuricemia to adopt a healthy diet and contribute to the application of natural products with anti-hyperuricemic activity.