Background: Gouty arthritis is characterized by the accumulation of monosodium urate crystals (MSU) in the synovial joints and surrounding tissues. Mastoparan M (Mast-M) is a biologically active ...peptide composed of 14 amino acids, extracted from wasp venom. This study aims to assess the impact of Mast-M on in vitro and in vivo gouty arthritis induced by lipolyaccharide (LPS) plus MSU crystal stimulation. Methods: PMA-differentiated THP-1 macrophages were pre-treated with Mast-M or left untreated, followed by stimulation with LPS and MSU crystals. Cell lysates were collected to assess the expression of the NLRP3 inflammasome, inflammatory signaling pathways, and oxidative stress. Furthermore, to evaluate the in vivo anti-inflammatory effect of Mast-M, an experimental acute gouty arthritis mouse model was established through intra-articular injection of MSU crystals. Results: Mast-M treatment demonstrated significant inhibition of the phosphorylation of MAPKS/NF-kappaB signaling pathways and reduction in oxidative stress expression in LPS and MSU-induced THP-1 macrophages. This resulted in the suppression of downstream NLRP3 inflammasome activation and IL-1beta release. In vivo, Mast-M effectively attenuated the inflammation induced by MSU in mice with gouty arthritis. Specifically, Mast-M reduced swelling in the paws, inhibited the infiltration of neutrophils and macrophages into periarticular tissue, and decreased the activation of the NLRP3 inflammasome and IL-1beta production. Conclusion: Mast-M significantly improves gouty arthritis, and its potential mechanism may be achieved by inhibiting the MAPK/NF-kappaB pathway and alleviating oxidative stress, thus suppressing the activation of NLRP3 inflammasomes. Keywords: Mastoparan M, NLRP3, MAPKs, NF-kappaB, oxidative stress, gout
Keywords High uric acid; Pancreatic beta-cell; Insulin resistance; Oxidative stress; Glycolysis Highlights * Insulin secretion disorder was found in mice with acute hyperuricemia. * High uric acid ...(HUA) impairs glycolytic pathway, and causes early apoptosis in pancreatic beta cells. * Pre-treatment with antioxidant (NAC) and insulin-like growth factor 1 (IGF-1) could recover HUA-decreased insulin secretion and glucose uptake by pancreatic beta cells. * HUA blocks IRS2/AKT signalling. Hyperuricaemia is a disorder of purine metabolism. Elevated serum uric acid is strongly associated with many diseases, including gout, abdominal obesity, insulin resistance, and cardiovascular and kidney disease. Our previous studies showed that high uric acid (HUA) induced insulin resistance in several peripheral organs, including the liver, myocardium and adipose tissue. However, whether HUA directly induces insulin resistance of pancreatic beta cells, the only source of insulin in the body and also a sensitive insulin target, is unknown. In this study, pancreatic beta cells pretreated with HUA showed impaired insulin expression/secretion, glucose uptake and the glycolytic pathway. RNA-seq revealed that HUA affected the biological processes of INS-1 cells broadly, including oxidoreduction coenzyme metabolic process, pyruvate metabolic process, and glycolytic process. In addition, HUA reduced mitochondrial membrane potential and increased the production of reactive oxygen species(ROS) in INS-1 cells. INS-1 cells pretreated with probenecid, an organic anion transporter inhibitor, protected INS-1 cells against HUA-induced insulin secretion decrease, Pretreatment with N-acetyl-L-cysteine(NAC), a globally used antioxidant, recovered HUA-decreased insulin secretion and glucose uptake by pancreatic beta cells. Insulin-like growth factor 1 (IGF-1), the phosphatidylinositol 3-kinase (PI3K) activator, rescues HUA-decreased insulin secretion by re-activating AKT phosphorylation. Thus, HUA induce insulin resistance, impaired insulin secretion and glycolytic pathway of pancreatic emicro cell through IRS2/AKT pathway. Author Affiliation: (a) Department of Endocrinology, Xiang'an Hospital of Xiamen University, Xiamen, Fujian, China (b) Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China (c) Division of Regenerative Medicine and Therapeutics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, Yonago, Japan (d) Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan * Corresponding authors. Article History: Received 12 May 2020; Revised 24 October 2020; Accepted 26 October 2020 (footnote)white star The authors have nothing to disclose. (footnote)1 Yaqiu Hu and Hairong Zhao contributed equally to this work. Byline: Yaqiu Hu (b,1), Hairong Zhao (a,1), Jiaming Lu (a), De Xie (a), Qiang Wang (a), Tianliang Huang (b), Hancheng Xin (b), Ichiro Hisatome (c), Tetsuya Yamamoto (d), Wei Wang wwei19742007@hotmail.com (a,**), Jidong Cheng jidongcheng36@hotmail.com (a,*)
A 43-year-old xanthinuric female was referred to our department because of hypouricemia. Routine laboratory data showed hypouricemia, a high level of plasma oxypurines, decreased urinary uric acid ...excretion, and increased urinary oxypurine excretion, with xanthine dehydrogenase activity in the duodenal mucosa below the limits of detection. In addition, allopurinol was not metabolized. From these findings, the patient was diagnosed with xanthinuria type II. To investigate the properties of xanthine dehydrogenase/xanthine oxidase (XDH/XO) deficiency, a cDNA sequence encoding XDH/XO, aldehyde oxidase (AO), and molybdenum cofactor sulferase (MCS), as well as immunoblotting analysis for XDH/XO protein, obtained from duodenal mucosa samples were performed. The XDH/XO cDNA and AO cDNA sequences of the xanthinuric patient were consistent with previously reported ones, whereas the MCS cDNA sequence revealed a point mutation of G to C in nucleotide 466, which changed codon 156 from GCC (Ala) to CCC (Pro). In addition, the MCS genomic DNA sequence including the site of the mutation revealed the same, suggesting that the xanthinuric patient was homozygous for this mutation. Such findings have not been previously reported for patients with xanthinuria type II.
Aims: Acute rupture or erosion of unstable atherosclerotic plaques is a major cause of adverse consequences of atherosclerotic cardiovascular disease, often leading to myocardial infarction or ...stroke. High uric acid (HUA) is associated with the increasing risk of cardiovascular events and death. However, the mechanism by which HUA promotes atherosclerosis and whether HUA affects plaque stability are still unclear. Methods: We constructed an atherosclerotic Apoe−/− mouse model with HUA. The progression of atherosclerosis and plaques was determined by Oil Red O staining, hematoxylin and eosin (H&E) staining, and Masson staining. TdT-mediated dUTP nick-end labeling assay and immunohistochemistry were used to observe the changes of apoptosis and autophagy in plaques, respectively. Then, we validated the in vivo results with RAW 264.7 cell line. Results: HUA promoted atherosclerosis and exacerbated plaque vulnerability, including significantly increased macrophage infiltration, lipid accumulation, enlarged necrotic cores, and decreased collagen fibers. HUA increased cell apoptosis and inhibited autophagy in plaques. In vitro results showed that HUA decreased cell viability and increased cell apoptosis in foam cells macrophages treated with oxidized low-density lipoprotein. An activator of autophagy, rapamycin, can partially reverse the increasing apoptosis. Conclusion: HUA promoted atherosclerosis and exacerbated plaque vulnerability, and HUA facilitates foam cell apoptosis by inhibiting autophagy.
Background: Mutations in human butyrylcholinesterase (BChE) are linked to low BChE activity and abnormal response to muscle relaxants.
Methods: Twenty Chinese patients with hepatic disease and low ...cholinesterase activity, and one Japanese patient and her mother were tested for BChE activity and BChE phenotype. The butyrylcholinesterase (BCHE gene) was amplified by polymerase chain reaction (PCR) and sequenced. Mutant BChE was expressed in 293 cells.
Results: A novel mutation was found in one Chinese patient at nucleotide 943, where A was changed to T (943 A→T), causing substitution of threonine 315 by serine (T315S). The T315S mutant had half of the normal BChE activity. One Japanese patient with low BChE activity had three nucleotide substitutions, 355 C→T, 988 T→A, and 1615 G→A. The amino acid substitutions were Q119stop, L330I, and A539T, respectively. The single mutant L330I had low BChE activity, but the double mutant L330I/A539T had normal activity.
Conclusions: The L330I and the novel T315S mutation caused a decreased BChE activity. The T315S mutation is one of the first BChE mutations reported in the Chinese population. Multiple mutations in BChE may interact with each other in an intramolecular manner.
To determine whether sauna bathing alone or in combination with beer ingestion increases the plasma concentration of uric acid, 5 healthy subjects were tested. Urine and plasma measurements were ...performed before and after each took a sauna bath, ingested beer, and ingested beer just after taking a sauna bath, with a 2-week interval between each activity. Sauna bathing alone increased the plasma concentrations of uric acid and oxypurines (hypoxanthine and xanthine), and decreased the urinary and fractional excretion of uric acid, while beer ingestion alone increased the plasma concentrations and urinary excretion of uric acid and oxypurines. A combination of both increased the plasma concentration of uric acid and oxypurines, and decreased the urinary and fractional excretion of uric acid, with an increase in the urinary excretion of oxypurines. The increase in plasma concentration of uric acid with the combination protocol was not synergistic as compared to the sum of the increases by each alone. Body weight, urine volume, and the urinary excretion of sodium and chloride via dehydration were decreased following sauna bathing alone. These results suggest that sauna bathing had a relationship with enhanced purine degradation and a decrease in the urinary excretion of uric acid, leading to an increase in the plasma concentration of uric acid. Further, we concluded that extracellular volume loss may affect the common renal transport pathway of uric acid and xanthine. Therefore, it is recommended that patients with gout refrain from drinking alcoholic beverages, including beer, after taking a sauna bath, since the increase in plasma concentration of uric acid following the combination of sauna bathing and beer ingestion was additive.
Gouty arthritis is characterized by the accumulation of monosodium urate crystals (MSU) in the synovial joints and surrounding tissues. Mastoparan M (Mast-M) is a biologically active peptide composed ...of 14 amino acids, extracted from wasp venom. This study aims to assess the impact of Mast-M on in vitro and in vivo gouty arthritis induced by lipolyaccharide (LPS) plus MSU crystal stimulation.
PMA-differentiated THP-1 macrophages were pre-treated with Mast-M or left untreated, followed by stimulation with LPS and MSU crystals. Cell lysates were collected to assess the expression of the NLRP3 inflammasome, inflammatory signaling pathways, and oxidative stress. Furthermore, to evaluate the in vivo anti-inflammatory effect of Mast-M, an experimental acute gouty arthritis mouse model was established through intra-articular injection of MSU crystals.
Mast-M treatment demonstrated significant inhibition of the phosphorylation of MAPKs/NF-κB signaling pathways and reduction in oxidative stress expression in LPS and MSU-induced THP-1 macrophages. This resulted in the suppression of downstream NLRP3 inflammasome activation and IL-1β release. In vivo, Mast-M effectively attenuated the inflammation induced by MSU in mice with gouty arthritis. Specifically, Mast-M reduced swelling in the paws, inhibited the infiltration of neutrophils and macrophages into periarticular tissue, and decreased the activation of the NLRP3 inflammasome and IL-1β production.
Mast-M significantly improves gouty arthritis, and its potential mechanism may be achieved by inhibiting the MAPK/NF-κB pathway and alleviating oxidative stress, thus suppressing the activation of NLRP3 inflammasomes.
AMP deaminase (AMPD) catalyzes AMP to IMP and plays an important role in energy charge and nucleotide metabolism. Human AMPD3 deficiency is a type of erythrocyte‐specific enzyme deficiency found in ...individuals without clinical symptoms, although an increased level of ATP in erythrocytes has been reported. To better understand the physiological and pathological roles of AMPD3 deficiency, we established a line of AMPD3‐deficient A3(−/−) mice. No AMPD activity and a high level of ATP were observed in erythrocytes of these mice, similar to human RBC‐AMPD3 deficiency, while other characteristics were unremarkable. Next, we created AMPD3 and pyruvate kinase (PK) double‐deficient PKA(−/−,−/−) mice by mating A3(−/−) mice with CBA‐Pk‐1slc/Pk‐1slc mice PK(−/−), a spontaneous PK‐deficient strain showing hemolytic anemia. In PKA(−/−,−/−) mice, the level of ATP in red blood cells was increased 1.5 times as compared to PK(−/−) mice, although hemolytic anemia in those animals was not improved. In addition, we observed osmotic fragility of erythrocytes in A3(−/−) mice under fasting conditions. In contrast, the ATP level in erythrocytes was elevated in A3(−/−) mice as compared to the control. In conclusion, AMPD3 deficiency increases the level of ATP in erythrocytes, but does not improve anemia due to PK deficiency and leads to erythrocyte dysfunction.
A 29-year-old woman was referred to our department because of gout. Routine laboratory data showed hyperuricemia, a high level of plasma oxypurines, increased urinary uric acid excretion, and ...increased urinary oxypurine excretion, with decreased hypoxanthine phosphoribosyl transferase (HPRT) activity in the erythrocytes. From these findings, the patient was diagnosed with a partial deficiency of HPRT. To determine its properties, a cDNA sequence encoding HPRT and the androgen receptor AR XIST minimal promoter gene, as well as methylation of the AR gene were investigated. The HPRT cDNA sequence revealed a point mutation of G to A in nucleotide 40, which changed codon 14 from GAA (Glu) to AAA (Lys) in the mutant gene. In addition, the HPRT genomic DNA sequence, including the mutation site, revealed the same point mutation, indicating that the patient was heterozygote. Further analysis of the AR gene on the X chromosome suggested nonrandom X-chromosome inactivation, whereas the AR XIST minimal promoter gene was normal. Such results have not been previously reported in a female with partial HPRT deficiency.
Most patients with hereditary hemochromatosis are homozygous for C282Y in the HFE gene in populations of Celtic origin, but the genetic cause of this disease is unknown in Japan because of its ...rarity. A 48-year-old Japanese patient was recently diagnosed with idiopathic hemochromatosis. Analysis of the entire coding region of the patient's HFE by RT-PCR showed a heterozygous nucleotide substitution at nucleotide 527 from C to T, which resulted in A176V amino acid substitution. Another mutation at nucleotide 942 from T to C was observed, but this was a nonsense mutation. C282Y and another mutation, H63D, were not found in the patient. The mutation may have a possible role on the cause of hemochromatosis in this Japanese case.
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