Project description:Approximately 15% of US adults have circulating levels of uric acid above its solubility limit, which is causally linked to the inflammatory disease gout. In most mammals, uric acid elimination is facilitated by the enzyme uricase. However, human uricase is a pseudogene, having been inactivated early in hominid evolution. Though it has long been known that a substantial amount of uric acid is eliminated in the gut, the role of the gut microbiota in hyperuricemia has not been studied. Here we identify a gene cluster, widely distributed in the gut microbiome, that encodes a pathway for uric acid degradation. Stable isotope tracing demonstrates that gut bacteria metabolize uric acid to xanthine or short chain fatty acids such as acetate, lactate and butyrate. Ablation of the microbiota in uricase-deficient mice causes profound hyperuricemia, and anaerobe-targeted antibiotics increase the risk of gout in humans. These data reveal a role for the gut microbiota in uric acid excretion and highlight the potential for microbiome-targeted therapeutics in hyperuricemia.
Project description:Natural flavonoid pectolinarigenin (PEC) was reported to alleviate tubulointerstitial fibrosis of unilateral ureteral obstruction (UUO) mice in our previous study. To further investigate nephroprotective effects of PEC in hyperuricemic nephropathy (HN), adenine and potassium oxonate induced HN mice and uric acid-treated mouse kidney epithelial (TCMK-1) cells were employed in the study. As a result, PEC significantly lowered serum uric acid level and restored hyperuricemia-related kidney injury in HN mice. Meanwhile, PEC alleviated inflammation, fibrosis and reduced adipokine FABP4 content in the kidneys of HN mice and uric acid-treated TCMK-1 cells. Mechanistically, PEC inhibited the TGF-β1 expression as well as the phosphorylation of transcription factor SMAD3 and STAT3 to regulate the corresponding inflammatory and fibrotic gene expression in kidney tissues. In conclusion, our results suggested that PEC could inhibit the activation of SMAD3 and STAT3 signaling to suppress inflammation and fibrosis, thereby alleviate HN in mice.
2022-02-18 | GSE190205 | GEO
Project description:Ferulic acid supplementation alleviates hyperuricemia in high-fructose/fat diet-fed rats via promoting uric acid excretion and mediating gut microbiota
Project description:Hyperuricemia is an essential risk factor in chronic kidney disease (CKD), while urate-lowering therapy to prevent or delay CKD is controversial. Alternatively activated macrophages in response to local microenvironment play diverse roles in kidney diseases. Here, we aim to investigate whether and how macrophage integrin αM (ITGAM) contributes to hyperuricemia-related CKD. In vivo, we explored dynamic characteristics of renal tissue in C57BL/6J mice with hyperuricemia-related CKD. By incorporating transcriptomics and phosphoproteomics data, we analyzed gene expression profile, hub genes and potential pathways. In vitro, we validated bioinformatic findings under different conditions with interventions corresponding to core nodes. We found that hyperuricemia-related CKD was characterized by elevated serum uric acid levels, impaired renal function, activation of macrophage alternative (M2) polarization, and kidney fibrosis. Integrated bioinformatic analyses revealed Itgam as the potential core gene and was associated with focal adhesion signaling. Notably, we confirmed the upregulated expression of macrophage ITGAM, activated pathway, and macrophage M2 polarization in injured kidneys. In vitro, through silencing Itgam, inhibiting p-FAK or p-AKT1 phosphorylation, and concurrent inhibiting of p-FAK while activating p-AKT1 all contributed to the modulation of macrophage M2 polarization. Our results indicated targeting macrophage ITGAM might be a promising therapeutic approach for preventing CKD.
Project description:Increased plasma uric acid (hyperuricemia) has been associated with worse outcomes for chronic kidney disease (CKD). But some attempts to control uric acid (UA) in large-cohort clinical trials did not produce clinically meaningful benefits for CKD. Some studies suggest that only hyperuricemia with crystals, but not asymptomatic hyperuricemia promotes the progression of CKD. Salt-sensitivity (SS) in blood pressure is a prevalent trait that is sexually dimorphic and results in kidney damage. But the connection between hyperuricemia and SS hypertension (HTN) is still unclear. Here we tested the connection between the two using both male and female Dahl SS rats, a well-establish model of SS HTN. We hypothesized that mild asymptomatic hyperuricemia is beneficial in controlling the progression of SS HTN. A uricase inhibitor, oxonic acid (2%) (Oxo) was used to induce hyperuricemia and high-salt (HS) (4% NaCl) diet was used to induce SS HTN. After 3 weeks, in response to oxonic acid supplementation, both sexes showed a significant increase of UA in plasma compared to their respective HS-only controls (Males: 0.63 ±0.07 vs. 2.17 ±0.34; Females: 0.78 ±0.15 vs. 2.04 ±0.35 mg/dl, HS vs. HS/oxo). Interestingly, only male HS/oxo rats showed a significant increase in uricosuria (Males: 0.23 ±0.03 vs. 0.45 ±0.06; Femaels: 0.26 ±0.06 vs. 0.26 ±0.001 UA/Cre, HS vs. HS/oxo). Moreover, the mild hyperuricemia was associated with a significant attenuation of the progression and magnitude of the mean arterial pressure in male but not female rats (Males: 157 ±3 vs. 136 ±3; Females: 155 ±6 vs. 154 ±5 mmHg, HS vs. HS/oxo). Xanthine oxidase (XO) is one of the enzymes that produce UA, and its activity has been shown to affect HTN as well. Therefore, we examined the level of XO activity in the plasma after the treatment. While there was no difference in the activity based on the diet within each sex, females had significantly lower levels of XO activity compared to males in each of the diets. To further investigate the beneficial phenotype seen in male rats, we evaluate changes in the progression of renal pathology. The HS/oxo group compared to the HS group had a lower kidney weight/body weight ratio and lower protein cast accumulation, indicating lower kidney damage. Furthermore, the HS/Oxo treated males had less oxidative damage in their tubules than the HS-only males. Bulk-RNA seq done on the male kidneys revealed that attenuated HTN phenotype was associated with an increased expression in Mas1 (MAS receptor), Klk-1 (Kallikrein-1), and Pcsk6 (PCSK6 enzyme) which can all lead to the activation of different vasodilatory pathways. Our study showed that in male but not female Dahl SS rats, asymptomatic mild hyperuricemia accompanied by hyperuricosuria ameliorates the progression of SS HTN and protects kidneys from further damage. Thus, our findings challenge the notion of hyperuricemia being inherently detrimental to health and highlight that this is an oversimplified view of UA’s role in disease.
2024-07-10 | GSE269511 | GEO
Project description:Therapeutic effects of Noni juice on Acute Gouty Arthritis
Project description:DCs and B cells are main target cells activated by uric acid (MSU, one of DAMP molecules). Ultimately, we would like to figure out signaling pathways significantly affected, and narrow down potential receptor candidates for uric acid (MSU).
Project description:Aim of the study This study aimed to evaluate the therapeutic efficacy of XZSWD against HUA-induced kidney injury and to elucidate the molecular pathways involved. Methods UPLC-QTOF/MS was used to identify compounds in XZSWD and medicated serum. A HUA mouse model was induced by potassium oxonate (PO) and hypoxanthine (HX) to evaluate the therapeutic effects of XZSWD on renal injury. RNA-Seq and CIBERSORT were applied to analyze gene expression and immune infiltration. Key signaling pathways were validated by qRT-PCR, Western blot, immunofluorescence, and flow cytometry. A THP-1/HK-2 co-culture system combined with SPP1 overexpression and knockdown was used to explore the molecular mechanisms underlying XZSWD’s anti-inflammatory and anti-fibrotic effects. Results 99 compounds were identified in XZSWDS. XZSWD reduced serum uric acid, improved renal function, and suppressed inflammation in HUA mice. RNA-Seq and CIBERSORT revealed downregulation of macrophage-related genes and enhanced mixed M1/M2 polarization. XZSWD inhibited the SPP1–CD44 axis and SRC/FAK/β-Catenin signaling, reducing Epithelial–Mesenchymal Transition (EMT) and Extracellular Matrix (ECM) deposition. In vitro, XZSWD suppressed uric acid-induced EMT and macrophage migration, polarization; these effects were reversed by SPP1 overexpression and enhanced by SPP1 knockdown, indicating SPP1 as a critical therapeutic target. Conclusions The XZSWD alleviates hyperuricemia-induced renal injury by effectively suppressing macrophage-mediated inflammation through coordinated regulation of the SPP1–CD44 axis and the SRC/FAK/β-Catenin signaling network.
Project description:Gouty Arthritis (GA) is caused by urate deposition in the joint capsule, cartilage, bone, and surrounding tissues to trigger recurrent attacks of acute joint inflammation. However, the clearance mechanism of urate deposition is still not clear. We aimed to investigate whether lymphatics vessels can drain monosodium and involve in the immune process of GA. Methods: Inguinal lymph nodes (LNs) in 4 normal volunteers and 4 patients with acute flare of GA were examined by ultrasound. Acute and chronic GA flare mouse models were established by intra-footpad administrations of monosodium urate (MSU) for 1 week or 1 month. Mice were treated with VEGFR-3 inhibitor or undergone popliteal lymph node (PLN) excision or PLN macrophage depletion. The severity of foot inflammation, lymphatic draining function, concentration of uric acid (UA), and macrophage population were examined. Macrophages were co-cultured with MSU-treated lymphatic endothelial cells (LECs) and differential gene expression of LECs was assessed by Agilent gene expression microarray. Results: 1) Draining LNs were enlarged in patients with GA flare and GA mouse models. 2) The lymphatic function and structure were abnormal in GA mouse models. 3) Acute GA mice had elevated UA levels in draining LNs, but not in the serum, while chronic GA mice had elevated UA levels in both LNs and serum. 4) Blockade of VEGFR-3 reduced foot inflammation in chronic GA mice. 5) MSU induces pro-inflammatory polarization of macrophages by inducing LEC inflammation. 6) PLN local depletion of macrophages or removal of PLNs alleviated foot inflammation in GA. Conclusions: Lymphatics drain MSU to the draining LNs to clear deposited urate in the distal extremity and induce LECs to stimulate macrophage pro-inflammatory response during GA. We have identified a novel mechanism about MSU clearance and pro-inflammatory macrophage activation, and provided possible therapeutic approach for GA.
Project description:In recent years, the increasing incidence of goose gout has caused serious economic losses. In this study, we explored the effects of lactulose on intestinal health and uric acid metabolism in geese, and used RNA-seq analysis to reveal its potential mechanism. 180 one-day-old Yangzhou geese were divided into three groups: control group (CG, basal diet), high protein model group (MG, containing 21 % crude protein diet), lactulose group (LS, containing 21 % crude protein diet + 0.3 % lactulose). Results showed that compared with the CG group and MG group, the LS group had significantly lower serum uric acid levels and intact ileal mucosal structure. Through bioinformatics analysis of transcriptome (GO and KEGG enrichment analysis, GSEA and trend analysis), we found key pathways and genes closely related to intestinal health and uric acid metabolism. These key findings include: zinc ion import across plasma membrane biological process, ABC Transporters pathway, Wnt signaling pathway, as well as ABCG2, a key gene for uric acid transport, and genes closely related to intestinal structural integrity (KLF2, LRP6, TJP1, TJP3, PROM1). The results showed that lactulose could effectively reduce the serum uric acid level of geese by improving intestinal morphology.