Mutations in the SLC2A9 Gene Cause Hyperuricosuria and Hyperuricemia in the Dog

Allantoin is the end product of purine catabolism in all mammals except humans, great apes, and one breed of dog, the Dalmatian. Humans and Dalmatian dogs produce uric acid during purine degradation, which leads to elevated levels of uric acid in blood and urine and can result in significant diseases in both species. The defect in Dalmatians results from inefficient transport of uric acid in both the liver and renal proximal tubules. Hyperuricosuria and hyperuricemia (huu) is a simple autosomal recessive trait for which all Dalmatian dogs are homozygous. Therefore, in order to map the locus, an interbreed backcross was used. Linkage mapping localized the huu trait to CFA03, which excluded the obvious urate transporter 1 gene, SLC22A12. Positional cloning placed the locus in a minimal interval of 2.5 Mb with a LOD score of 17.45. A critical interval of 333 kb containing only four genes was homozygous in all Dalmatians. Sequence and expression analyses of the SLC2A9 gene indicated three possible mutations, a missense mutation (G616T;C188F) and two promoter mutations that together appear to reduce the expression levels of one of the isoforms. The missense mutation is associated with hyperuricosuria in the Dalmatian, while the promoter SNPs occur in other unaffected breeds of dog. Verification of the causative nature of these changes was obtained when hyperuricosuric dogs from several other breeds were found to possess the same combination of mutations as found in the Dalmatian. The Dalmatian dog model of hyperuricosuria and hyperuricemia underscores the importance of SLC2A9 for uric acid transport in mammals

Transforming growth factor-β-inducible early response gene 1 is a novel substrate for atypical protein kinase Cs

The protein kinase C (PKC) family of serine/threonine kinases consists of ten different isoforms grouped into three subfamilies, denoted classical, novel and atypical PKCs (aPKCs). The aPKCs, PKCι/λ and PKCζ serve important roles during development and in processes subverted in cancer such as cell and tissue polarity, cell proliferation, differentiation and apoptosis. In an effort to identify novel interaction partners for aPKCs, we performed a yeast two-hybrid screen with the regulatory domain of PKCι/λ as bait and identified the Krüppel-like factors family protein TIEG1 as a putative interaction partner for PKCι/λ. We confirmed the interaction of both aPKCs with TIEG1 in vitro and in cells, and found that both aPKCs phosphorylate the DNA-binding domain of TIEG1 on two critical residues. Interestingly, the aPKC-mediated phosphorylation of TIEG1 affected its DNA-binding activity, subnuclear localization and transactivation potential

Quercetin and Allopurinol Ameliorate Kidney Injury in STZ-Treated Rats with Regulation of Renal NLRP3 Inflammasome Activation and Lipid Accumulation

Hyperuricemia, hyperlipidemia and inflammation are associated with diabetic nephropathy. The NLRP3 inflammasome-mediated inflammation is recently recognized in the development of kidney injury. Urate and lipid are considered as danger signals in the NLRP3 inflammasome activation. Although dietary flavonoid quercetin and allopurinol alleviate hyperuricemia, dyslipidmia and inflammation, their nephroprotective effects are currently unknown. In this study, we used streptozotocin (STZ)-induced diabetic nephropathy model with hyperuricemia and dyslipidemia in rats, and found over-expression of renal inflammasome components NLRP3, apoptosis-associated speck-like protein and Caspase-1, resulting in elevation of IL-1β and IL-18, with subsequently deteriorated renal injury. These findings demonstrated the possible association between renal NLRP3 inflammasome activation and lipid accumulation to superimpose causes of nephrotoxicity in STZ-treated rats. The treatment of quercetin and allopurinol regulated renal urate transport-related proteins to reduce hyperuricemia, and lipid metabolism-related genes to alleviate kidney lipid accumulation in STZ-treated rats. Furthermore, quercetin and allopurinol were found to suppress renal NLRP3 inflammasome activation, at least partly, via their anti-hyperuricemic and anti-dyslipidemic effects, resulting in the amelioration of STZ-induced the superimposed nephrotoxicity in rats. These results may provide a basis for the prevention of diabetes-associated nephrotoxicity with urate-lowering agents such as quercetin and allopurinol

Gene and protein expression of O-GlcNAc-cycling enzymes in human laryngeal cancer

Aberrant protein O-GlcNAcylation may contribute to the development and malignant behavior of many cancers. This modification is controlled by O-linked β-N-acetylglucosamine transferase (OGT) and O-GlcNAcase (OGA). The aim of this study was to determine the expression of O-GlcNAc cycling enzymes mRNA/protein and to investigate their relationship with clinicopathological parameters in laryngeal cancer. The mRNA levels of OGT and MGEA5 genes were determined in 106 squamous cell laryngeal cancer (SCLC) cases and 73 non-cancerous adjacent laryngeal mucosa (NCLM) controls using quantitative real-time PCR. The level of OGT and OGA proteins was analyzed by Western blot. A positive expression of OGT and MGEA5 transcripts and OGT and OGA proteins was confirmed in 75.5 and 68.9 % and in 43.7 and 59.4 % samples of SCLC, respectively. Higher levels of mRNA/protein for both OGT and OGA as well as significant increases of 60 % in total protein O-GlcNAcylation levels were noted in SCLC compared with NCLM (p < 0.05). As a result, an increased level of OGT and MGEA5 mRNA was related to larger tumor size, nodal metastases, higher grade and tumor behavior according to TFG scale, as well as incidence of disease recurrence (p < 0.05). An inverse association between OGT and MGEA5 transcripts was determined with regard to prognosis (p < 0.05). In addition, the highest OGT and OGA protein levels were observed in poorly differentiated tumors (p < 0.05). No correlations with other parameters were noted, but the results showed a trend of more advanced tumors to be more frequently OGT and OGA positive. The results suggest that increased O-GlcNAcylation may have an effect on tumor aggressiveness and prognosis in laryngeal cancer.This work was supported, in part, by a grant from the National Science Council, Poland (N403 043 32/2326), by the statutory fund of the Department of Cytobiochemistry, University of Łódź, Poland (506/811

Níveis de teonina em rações para tilápias-do-nilo Threonine levels in diets for Nile tilapia

Este estudo foi realizado para determinar a exigência de treonina para tilápia-do-nilo. Os peixes (37,61 &plusmn; 1,16 g de peso inicial) foram distribuídos em um delineamento inteiramente casualizado, com quatro tratamentos, três repetições e 25 peixes por unidade experimental. Foi utilizada uma ração-referência (27% de PB e 3.000 kcal de ED/kg) suplementada com L-treonina, resultando em rações com 0,92; 1,06; 1,21 e 1,35% de treonina total. Os aminoácidos sintéticos foram adicionados para manutenção do perfil de aminoácidos, de acordo com o conceito de proteína ideal. Os peixes foram alimentados até saciedade aparente durante 110 dias. Não foram observados efeitos dos níveis de treonina nas rações sobre o consumo de ração, o peso do fígado, o índice hepato-somático, os rendimentos de carcaça e de filé e a composição do filé em água (PB e EE). Constatou-se aumento linear sobre o ganho de peso, a conversão alimentar, a taxa de eficiência protéica, a retenção de nitrogênio, os pesos da carcaça e do filé e o teor de cinzas no filé. Considerando os resultados de desempenho, de custo/kg de ganho de peso e de custo/kg de peso em filés, pode-se inferir que tilápias-do-nilo de 38 a 351 g criadas em tanques-rede necessitam de 1,35% de treonina na ração - 5,51% da proteína digestível ou 74% de lisina (com base no conceito de proteína ideal).<br>This experiment was conducted to determine the dietary threonine requirements for Nile tilapia. The fishes (37.61 &plusmn; 1.16 of initial weight) were allotted to a completely randomized design with four treatments, three replicates and 25 fishes per experimental unit. It was used a reference diet with 27% of CP and 3,000 kcal of DE/kg, supplemented with L-threonine, resulting in diets with 0.92, 1.06, 1.21, and 1.35% of total threonine. Synthetic amino acids were added to mantain their profile according to the ideal protein concept. Fishes were fed ad libitum during 110 days. No effects of dietary threonine levels on feed intake, liver weight, hepatic somatic index, carcass yield, fillet yield and fillet water composition (CP and EE) were observed. It was observed linear increase on weight gain, feed:gain ratio, protein efficiency rate, nitrogen retention, carcass weight, fillet weight and ash content in fillet. Considering data of performance, cost/kg of weight gain and cost/kg of fillet weight, the dietary total threonine requirement is of 1.35% [5.51% of digestible protein or 74% of lysine (based on the ideal protein concept)] for Nile tilapia from 38 to 351 g, reared in net pens

SLC2A9 influences uric acid concentrations with pronounced sex-specific effects

Serum uric acid concentrations are correlated with gout and clinical entities such as cardiovascular disease and diabetes. In the genome-wide association study KORA (Kooperative Gesundheitsforschung in der Region Augsburg) F3 500K (n = 1,644), the most significant SNPs associated with uric acid concentrations mapped within introns 4 and 6 of SLC2A9, a gene encoding a putative hexose transporter (effects: -0.23 to -0.36 mg/dl per copy of the minor allele). We replicated these findings in three independent samples from Germany (KORA S4 and SHIP (Study of Health in Pomerania)) and Austria (SAPHIR; Salzburg Atherosclerosis Prevention Program in Subjects at High Individual Risk), with P values ranging from 1.2 × 10-8 to 1.0 × 10 -32. Analysis of whole blood RNA expression profiles from a KORA F3 500K subgroup (n = 117) showed a significant association between the SLC2A9 isoform 2 and urate concentrations. The SLC2A9 genotypes also showed significant association with self-reported gout. The proportion of the variance of serum uric acid concentrations explained by genotypes was about 1.2% in men and 6% in women, and the percentage accounted for by expression levels was 3.5% in men and 15% in women