Genome-wide association study implicates the role of TBXAS1 in the pathogenesis of depressive symptoms among the Korean population.

Although depression is an emerging disorder affecting many people worldwide, most genetic studies have been performed in European descent populations. Herein, a genome-wide association study (GWAS) was conducted in Korean population to elucidate the genomic loci associated with depressive symptoms. Two independent cohorts were used as discovery datasets, which consisted of 6474 (1484 cases and 4990 controls) and 1654 (557 cases and 1097 controls) Korean participants, respectively. The participants were divided into case and control groups based on the Beck Depression Inventory (BDI). Meta-analysis using the two cohorts revealed that rs6945590 was significantly associated with the risk of depressive symptoms [P = 2.83 × 10-8; odds ratio (OR) = 1.23; 95% confidence interval (CI): 1.15-1.33]. This association was validated in other independent cohorts which were another Korean cohort (258 cases and 1757 controls) and the East Asian study of the Psychiatric Genomics Consortium (PGC) (12,455 cases and 85,548 controls). The predicted expression levels of thromboxane A synthase 1 gene (TBXAS1), which encodes the enzyme thromboxane A synthase 1 and participates in the arachidonic acid (AA) cascade, was significantly decreased in the whole blood tissues of the participants with depressive symptoms. Furthermore, Mendelian randomization (MR) analysis showed a causal association between TBXAS1 expression and the risk of depressive symptoms. In conclusion, as the number of risk alleles (A) of rs6945590 increased, TBXAS1 expression decreased, which subsequently caused an increase in the risk of depressive symptoms.

The Role and Regulation of Thromboxane A2 Signaling in Cancer-Trojan Horses and Misdirection.

Over the last two decades, there has been an increasing awareness of the role of eicosanoids in the development and progression of several types of cancer, including breast, prostate, lung, and colorectal cancers. Several processes involved in cancer development, such as cell growth, migration, and angiogenesis, are regulated by the arachidonic acid derivative thromboxane A2 (TXA2). Higher levels of circulating TXA2 are observed in patients with multiple cancers, and this is accompanied by overexpression of TXA2 synthase (TBXAS1, TXA2S) and/or TXA2 receptors (TBXA2R, TP). Overexpression of TXA2S or TP in tumor cells is generally associated with poor prognosis, reduced survival, and metastatic disease. However, the role of TXA2 signaling in the stroma during oncogenesis has been underappreciated. TXA2 signaling regulates the tumor microenvironment by modulating angiogenic potential, tumor ECM stiffness, and host immune response. Moreover, the by-products of TXA2S are highly mutagenic and oncogenic, adding to the overall phenotype where TXA2 synthesis promotes tumor formation at various levels. The stability of synthetic enzymes and receptors in this pathway in most cancers (with few mutations reported) suggests that TXA2 signaling is a viable target for adjunct therapy in various tumors to reduce immune evasion, primary tumor growth, and metastasis.

TBXAS1 Gene Polymorphism Is Associated with the Risk of Ischemic Stroke of Metabolic Syndrome in a Chinese Han Population.

Objective: To investigate the association between thromboxane A synthase 1 (TBXAS1) gene polymorphism and metabolic syndrome (MS) and explore whether gene polymorphism could act as biomarkers in MS and its components or whether it could play a role in MS-related damage. Methods: A total of 3072 eligible subjects were obtained, of which 1079 cases were controls and 1993 cases were MS patients. Subjects were followed up for 5 years, and the endpoint were recorded. The gene polymorphism of TBXAS1 was detected by using the Sequenom MassArray method. Results: Significant differences were observed in ischemic stroke and NC_000007.14: g.139985896C>T (P < 0.05). The incidence of ischemic stroke was significantly higher in T allele carriers than in C (P < 0.05). C allele was the protective factor of the onset of ischemic stroke. There were negative interactions between C allele and waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and fasting plasma glucose (FPG). Conclusion: These findings suggest that NC_000007.14: g.139985896C>T was related to the incidence of ischemic stroke in the whole and MS population, and individuals who carry the C allele have a reduced risk of ischemic stroke, which may be used as a promising biomarker of disease risk in patients with MS.

Novel compound heterozygous variants of TBXAS1 presenting with Ghosal hematodiaphyseal dysplasia treated with steroids.

BACKGROUND: Homozygous or compound heterozygous pathogenic variants in the thromboxane A synthase 1 (TBXAS1) gene are associated with Ghosal hematodiaphyseal dysplasia (GHDD) which is characterized by defective hematopoiesis and increased bone density of long bones. METHODS: Patients 1 and 2 are identical twins, who presented with red blood cell transfusion-dependent normocytic anemia and thrombocytopenia with bone marrow fibrosis and cortical bone thickening of long bones on plain radiograph. To clarify the etiology of their anemia and thrombocytopenia, whole blood was used for the DNA extraction and analyzed using next-generation sequencing (NGS) on an in-house bone marrow failure syndrome panel. RESULTS: The NGS results indicated that these two patients carried two heterozygous variants in TBXAS1, exon7, c.583_584del, p.Ala195Leufs*12, and exon12, c.1420G>T, p.Gly474Trp, which were inherited from their mother and father, respectively. Patients 1 and 2 have been on chronic oral steroids with normalization of hemoglobin and platelet count after steroid initiation. Patient 3 is their sister who has normal blood counts but also has the same variants in TBXAS1 as her brothers. Radiographs showed cortical bone thickening and she has not required any treatment or transfusion. CONCLUSION: We report three Caucasian siblings from non-consanguineous parents with novel compound heterozygous variants of TBXAS1 presenting with the phenotypes of GHDD. These three cases illustrate the variable clinical expressivity of the GHDD from two-compound heterozygous pathogenic variants of TBXAS1.

Thromboxane A2 Synthase and Thromboxane Receptor Deletion Reduces Ischaemia/Reperfusion-Evoked Inflammation, Apoptosis, Autophagy and Pyroptosis.

AIM: Enhancement of thromboxane A2 (TXA2) synthase (TXAS) activity, TXA2 release, and thromboxane prostanoid (TP) receptor activation leads to vasoconstriction and oxidative injury. We explored whether genetic deletion of TXAS/TXA2/TP signalling may reduce renal ischaemia/reperfusion (I/R) injury in mice. MATERIALS AND METHODS: Renal haemodynamics and function were evaluated in TXAS+/+TP+/+ (wild-type, WT), TXAS-/- (TXS-/-), TP-/- and TXAS-/-TP-/- (double knockout, dKO) mice in response to intravenous TXA2 mimetic-U46619 and 45-minute renal ischaemia and 4-hour reperfusion injury. We examined renal TXAS and TP expression, blood urea nitrogen (BUN) and creatinine, reactive oxygen species (ROS) amount, pro-inflammatory cytokines and pathophysiologic mechanisms, including apoptosis, autophagy and pyroptosis under I/R injury. RESULTS: Renal I/R enhanced the levels of TXAS, TP, nuclear factor-κB, nicotinamide adenine dinucleotide phosphate oxidase gp91, Bax/Bcl-2/caspase-3/apoptosis, Beclin-1/LC3-II/autophagy, caspase-1/gasdermin D/interleukin-1ß/pyroptosis, renal thromboxane B2 (TXB2) concentration, ROS amount, plasma BUN, creatinine and TXB2 and decreased renal endothelial nitric oxide synthase expression in WT mice. All these enhanced parameters were significantly decreased in three KO mice. Intravenous U46619 significantly decreased renal microcirculation and enhanced gp91 and Bax/Bcl-2 in WT and TXS-/- but not TP-/- in dKO mice. I/R significantly decreased renal microcirculation in all mice; however, the time for recovery to baseline renal blood flow level was significantly shortened in TXS-/-, TP-/-and dKO mice versus WT mice. Blockade of TXAS/TP signalling attenuated I/R-enhanced pro-inflammatory cytokine profile. CONCLUSION: Blockade of TXAS/TXA2/TP signalling confers renal protection against I/R injury through the actions of anti-oxidation, anti-inflammation, anti-apoptosis, anti-autophagy and anti-pyroptosis.

A novel single-chain enzyme complex with chain reaction properties rapidly producing thromboxane A2 and exhibiting powerful anti-bleeding functions.

Uncontrollable bleeding is still a worldwide killer. In this study, we aimed to investigate a novel approach to exhibit effective haemostatic properties, which could possibly save lives in various bleeding emergencies. According to the structure-based enzymatic design, we have engineered a novel single-chain hybrid enzyme complex (SCHEC), COX-1-10aa-TXAS. We linked the C-terminus of cyclooxygenase-1 (COX-1) to the N-terminus of the thromboxane A2 (TXA2 ) synthase (TXAS), through a 10-amino acid residue linker. This recombinant COX-1-10aa-TXAS can effectively pass COX-1-derived intermediate prostaglandin (PG) H2 (PGH2 ) to the active site of TXAS, resulting in an effective chain reaction property to produce the haemostatic prostanoid, TXA2 , rapidly. Advantageously, COX-1-10aa-TXAS constrains the production of other pro-bleeding prostanoids, such as prostacyclin (PGI2 ) and prostaglandin E2 (PGE2 ), through reducing the common substrate, PGH2 being passed to synthases which produce aforementioned prostanoids. Therefore, based on these multiple properties, this novel COX-1-10aa-TXAS indicated a powerful anti-bleeding ability, which could be used to treat a variety of bleeding situations and could even be useful for bleeding prone situations, including nonsteroidal anti-inflammatory drugs (NSAIDs)-resulted TXA2 -deficient and PGI2 -mediated bleeding disorders. This novel SCHEC has a great potential to be developed into a biological haemostatic agent to treat severe haemorrhage emergencies, which will prevent the complications of blood loss and save lives.

miR-34b-3p May Promote Antiplatelet Efficiency of Aspirin by Inhibiting Thromboxane Synthase Expression.

Aspirin has been widely used for the prevention of cardiovascular diseases, but its antiplatelet efficiency varies between individuals. The present study aimed to evaluate response to aspirin based on gene profiles as well as potential regulating pathways using human blood samples and cell lines. Platelet function in patients 50 years or older with coronary artery disease on 100 mg/day aspirin was measured by light transmission aggregometry (LTA) of arachidonic acid (AA)-induced platelet aggregation. The expression of eight candidate genes-PTGS1/COX1, PLA2G4A, PLA2G6, PLA2G7, TBXAS1, TBXA2R, PTGIR, and ITGA2B-and the ingredients involved in AA metabolism were analyzed. Our data showed that the expressions of thromboxane A synthase 1 (TBXAS1), thromboxane synthase (TXS), and thromboxane B2 (TXB2) were increased in the upper quartile of platelet aggregation (LTA-AA_Q4) group compared with the lower quartile of platelet aggregation (LTA-AA_Q1) group. Our bioinformatics analysis suggested that TBXAS1 was targeted by miR-34b-3p via binding to its 3'-UTR, which was subsequently verified experimentally. Although overexpression of miR-34b-3p exhibited no apparent effect on cell proliferation, inhibition of miR-34b-3p promoted megakaryocyte viability. Our data demonstrated that the expression of TBXAS1 was higher in the aspirin hyporesponsiveness group than that in the hyperresponsiveness group, suggesting that high expression of TBXAS1 may be associated with aspirin hyporesponsiveness. miR-34b-3p may regulate the platelet and aspirin response by suppressing TBXAS1 expression and megakaryocyte proliferation.

Thromboxane A synthase 1 gene expression and promotor haplotypes are associated with risk of large artery-atherosclerosis stroke in Iranian population.

Large artery atherosclerosis (LAA) is known as an important cause of ischemic stroke (IS), which is a multifactorial disorder. Many candidate genes have been proposed for IS like (TBXAS1) that plays a significant role in LAA stroke pathogenesis. This is the first study on the evaluation of the association of the five single-nucleotide polymorphisms (SNPs) in TBXAS1 promoter region and the level of TBXAS1 transcript with large-artery atherosclerosis stroke. Five SNPs in TBXAS1 genes were investigated in 248 patients with large-artery atherosclerosis stroke and 199 healthy controls in Iranian population in this case-control study through using the high-resolution melting assay. In addition, the relationships between the selected SNPs with alteration of TBXAS1 gene expressions were investigated in terms of blood platelets through the reverse transcription-quantitative polymerase chain reaction. Multivariate logistic analysis with adjustments indicated that rs10256282CC, rs10237429CC, and rs4590360GG genotypes were associated with large-artery atherosclerosis stroke (adjusted odds ratio = 2.804, 2.872, and 2.432, respectively; P < 0.05, q < 0.05). Furthermore, the frequency of CACCG haplotype in the patients was greatly higher than that in the controls (OR = 1.424, 95% CI: 1.071-1.893, P = 0.014738). In addition, TBXAS1 expression was higher in patients compared to the controls (P = 0.021), and individuals with the homozygous mutated genotypes of these SNPs showed a higher expression level compared to other genotype (P < 0.05). In total, our findings indicate a significant association of TBXAS1 gene rs10256282CC, rs10237429CC, and rs4590360GG polymorphisms with large-artery atherosclerosis stroke susceptibility and the level of TBXAS1 expression, which was not previously reported in any population.

Genetic Depletion of Thromboxane A2/Thromboxane-Prostanoid Receptor Signalling Prevents Microvascular Dysfunction in Ischaemia/Reperfusion Injury.

OBJECTIVE: Activation of thromboxane A2 synthase (TXAS)/thromboxane A2 (TXA2)/thromboxane prostanoid (TP) receptor leads to arterial constriction, platelet aggregation and vascular injury. We attempted to characterize the microvascular dysfunction in ischaemia/reperfusion injury using genetically modified TXAS-/-, TP-/- and TXAS-/-TP-/- mice. APPROACH AND RESULTS: The cardiac micro-circulation and electrocardiograms were evaluated from B6, TXAS-/-, TP-/- and TXAS-/-TP-/- mice in response to intravenous saline, endothelin-1, U46619 (a TXA2 agonist) and myocardial ischaemia/reperfusion injury. Cardiac function was investigated with myocardial permeability, the troponin I concentration and the infarct size. Myocardial TXAS, TP, endothelial nitric oxide (NO) synthase (eNOS), nicotinamide adenine dinucleotide phosphate oxidase 4 (NOx4), 4-hydroxynonenal, interleukin (IL)-1ß, cell apoptosis, coronary effluent thromboxane B2 (TXB2) and superoxide anions (O2 -) and NO concentrations were measured. Mice mesenteric reactivity in response to various drugs was assessed by wire myography. In vivo fluorescent platelet adhesiveness to the mesenteric arterial endothelium after FeCl3 stimulation was examined. In B6 mice, ischaemia/reperfusion significantly increased levels of ST-segment elevation, myocardial TXAS, TP, NOx4, IL-1ß, apoptosis, coronary endothelin-1, TXB2, O2 - release and the infarct size, with concomitant decreases in eNOS, NO concentrations and cardiac micro-circulation. These effects were remarkably depressed in TXAS-/-, TP-/- and TXAS-/-TP-/- mice. Aspirin treatment or depletion of the TXAS, TP or TXAS/TP gene significantly attenuated the exaggerated vascular reactivity by vasoconstrictors and vasodilators and efficiently reduced platelet adhesion to the mesenteric endothelium under FeCl3 stimulation. CONCLUSION: Inhibiting TXAS/TXA2/TP signalling confers microvascular protection against oxidative injury in both cardiac and mesenteric arteries.

Prostaglandin E1-Mediated Collateral Recruitment Is Delayed in a Neonatal Rat Stroke Model.

While arterial reflow after a stroke represents an important challenge for better outcomes, it is also very important that sudden recanalization does not produce local oxidative and nitrogen species, deleterious for the brain and more particularly the immature brain. Our objective was to determine whether a supply in prostaglandin (Pg) E1 (Alprostadil), via its action on arterial pressure, might progressively improve cerebral reperfusion in a neonatal stroke model. Arterial blood flow was measured using ultrasonography. Rate-limiting and Pg terminal synthesizing enzymes were evaluated using reverse-transcriptase polymerase chain reaction. Our data suggests that a supply in PgE1 might delay and improve the ipsilateral reperfusion by decreasing thromboxane A synthase-1 gene, the density of reactive astrocytes and lesion volume.

Thromboxane A Synthase: A New Target for the Treatment of Cardiovascular Diseases.

Atherothrombosis-related diseases are one of the world's leading causes of mortality, and thus the search for new therapeutic approaches in this area remains a very urgent task. Modern pharmacogenomic technologies make it possible to obtain valuable data on disease pathogenesis and optimal therapeutic approaches. One promising research direction is the study of the thromboxane A2 - thromboxane A synthase - thromboxane A2 receptor axis. This review summarizes the recent evidence and suggests that systematic works in this area are creating new and promising opportunities in the treatment of patients with cardiovascular diseases.

Genetic variants of PTGS2, TXA2R and TXAS1 are associated with carotid plaque vulnerability, platelet activation and TXA2 levels in ischemic stroke patients.

Eicosanoids may play a role in ischemic stroke. However, the associations of variants in cyclooxygenase (COX) pathway genes and interaction among these variants with carotid plaque vulnerability are not fully understood. In present study, twelve variants in COX pathway genes were examined using matrix-assisted laser desorption ionization time-of-flight mass spectrometry method in 396 patients with ischemic stroke and 291 controls. Platelet aggregation, platelet-leukocyte aggregates, and urine 11-dehydrothromboxane B2 (11-dTxB2) were also measured. According to the results of carotid high-resolution B-mode ultrasound, the patients were stratified into the following groups [i.e., non-carotid plaque and carotid plaque. The carotid plaque was further classified into subgroups of echolucent plaque (ELP) and echogenic plaque (EGP)]. Additionally, gene-gene interactions were analyzed to assess whether there was any interactive role for assessed variants in affecting carotid plaque vulnerability, platelet activation and 11-dTxB2 levels. There were no significant differences in the frequencies of genotypes of the twelve variants between patients and controls. Among 396 patients, 294 cases (74.2%) had carotid plaques (106 had ELP, 188 had EGP). Frequency of PTGS2 rs20417CC, TXAS1 rs2267679TT, TXAS1 rs41708TT, PTGIS rs5602CC, and TXA2R rs1131882TT genotype was significantly higher in patients with plaque compared with patients without plaque, or in patients with ELP compared with patients with EGP. 11-dTxB2 levels, platelet aggregation and platelet-leukocyte aggregates were significantly higher in patients with ELP compared with patients without plaque or with EGP. Multivariate logistic regression analysis revealed that PTGS2 rs20417CC, TXA2R rs1131882TT, and high-risk interaction among variants in PTGS2 rs20417, TXA2R rs1131882 and TXAS1 rs41708 were independently associated with the risk of ELP after adjusting for confounding variables. The variants in COX pathway genes and the high-risk interactions among variants in PTGS2 rs20417, TXA2R rs1131882 and TXAS1 rs41708 were associated with high 11-dTxB2 and platelet activation, and independently associated with the risk of carotid plaque vulnerability. These variants might be potential markers for plaque instability.

Interactions among Variants in Eicosanoid Genes Increase Risk of Atherothrombotic Stroke in Chinese Populations.

BACKGROUND: Eicosanoids are lipid mediators that may play a role in ischemic stroke (IS). However, the association of variants in eicosanoid genes and these interactions with IS risk has not been investigated. The aim of the present study was to investigate the association of 11 variants in eicosanoid genes with IS and to determine whether these gene-gene interactions increase the risk of IS. METHODS: Eleven variants in prostaglandin H synthase-1 (PTGS1), PTGS2, thromboxane A2 synthase (TBXAS1), prostacyclin synthase (PTGIS), and prostaglandin E synthase (PTGES) genes were examined using mass spectrometry method in 297 patients with atherothrombotic stroke and 291 controls. Gene-gene interactions were analyzed using generalized multifactor dimensionality reduction (GMDR) method. Platelet aggregation and platelet-leukocyte aggregates were measured on admission. RESULTS: There were no significant differences in the genotype distributions of the 11 variants between patients and controls. However, GMDR analysis showed a significant gene-gene interaction among rs20417, rs5602, and rs41708, which scored 10 for cross-validation consistency and 9 for the sign test (P = .014). Logistic regression analysis showed that high-risk interaction among rs20417, rs5602, and rs41708 was an independent risk factor for atherothrombotic stroke (OR = 2.45, 95% CI: 1.33-3.27, P = .019). The high-risk interactive genotypes were associated with higher platelet aggregation and platelet-leukocyte aggregates. CONCLUSIONS: PTGS2 rs20417, PTGIS rs5602, and TBXAS1 rs41708 three-locus interactions may confer a higher risk for atherothrombotic stroke. The combinatorial analysis used in this study may be helpful to elucidate complex genetic risk for IS.

Extracellular histones disarrange vasoactive mediators release through a COX-NOS interaction in human endothelial cells.

Extracellular histones are mediators of inflammation, tissue injury and organ dysfunction. Interactions between circulating histones and vascular endothelial cells are key events in histone-mediated pathologies. Our aim was to investigate the implication of extracellular histones in the production of the major vasoactive compounds released by human endothelial cells (HUVECs), prostanoids and nitric oxide (NO). HUVEC exposed to increasing concentrations of histones (0.001 to 100 µg/ml) for 4 hrs induced prostacyclin (PGI2) production in a dose-dependent manner and decreased thromboxane A2 (TXA2) release at 100 µg/ml. Extracellular histones raised cyclooxygenase-2 (COX-2) and prostacyclin synthase (PGIS) mRNA and protein expression, decreased COX-1 mRNA levels and did not change thromboxane A2 synthase (TXAS) expression. Moreover, extracellular histones decreased both, eNOS expression and NO production in HUVEC. The impaired NO production was related to COX-2 activity and superoxide production since was reversed after celecoxib (10 µmol/l) and tempol (100 µmol/l) treatments, respectively. In conclusion, our findings suggest that extracellular histones stimulate the release of endothelial-dependent mediators through an up-regulation in COX-2-PGIS-PGI2 pathway which involves a COX-2-dependent superoxide production that decreases the activity of eNOS and the NO production. These effects may contribute to the endothelial cell dysfunction observed in histone-mediated pathologies.

Variants in COX-2, PTGIS, and TBXAS1 Are Associated with Carotid Artery or Intracranial Arterial Stenosis and Neurologic Deterioration in Ischemic Stroke Patients.

BACKGROUND: Eicosanoids may play a role in ischemic stroke (IS). However, the association of variants in eicosanoid genes with symptomatic carotid artery or intracranial arterial stenosis and neurologic deterioration (ND) is not fully understood. The aim of the present study was to investigate the association of 11 variants in eicosanoid genes with symptomatic carotid artery or intracranial arterial stenosis and ND. METHODS: Eleven variants in eicosanoid genes were examined using mass spectrometry method in 297 IS patients. The symptomatic carotid artery or intracranial arterial stenosis was assessed by computed tomographic angiography. Platelet aggregation and platelet-leukocyte aggregates were measured. The primary outcome was ND within 10 days of admission. ND was defined as an increase of 2 or more points in National Institutes of Health Stroke Scale score. RESULTS: Among 297 IS patients, 182 (61.3%) cases had symptomatic carotid artery or intracranial arterial stenosis, and 88 (29.6%) patients experienced ND within 10 days after admission. Symptomatic carotid artery or intracranial arterial stenosis was significantly associated with higher ND (P < .001). Rs20417CC, rs41708TT, and rs5629CC were independent risk factors for symptomatic carotid artery or intracranial arterial stenosis and ND, and associated with higher platelet aggregation and platelet-leukocyte aggregates. CONCLUSIONS: Symptomatic carotid artery or intracranial arterial stenosis was associated with higher ND. Rs20417CC, rs41708TT, and rs5629CC were not only independent risk factors for symptomatic carotid artery or intracranial arterial stenosis, but also independent risk predictors for ND.

Ghosal Type Hematodiaphyseal Dysplasia.

BACKGROUND: Ghosal Type Hematodiaphyseal Dysplasia is an autosomal recessive disorder characterized by refractory anemia and diaphyseal bone dysplasia. CASE CHARACTERISTICS: A 3 y 9 mo-old male child presented with progressive anemia and bowing of thighs. Child was found to have a previously reported homozygous point mutation c.1238G>A, (p.Arg413Glu) in Exon 16 of TBXAS1 gene. OUTCOME: Low dose steroid therapy resulted in normalization of hemoglobin and prevented further progression of bony changes. MESSAGE: Refractory anemia in association with bony deformities should prompt pediatricians to investigate for inherited bony dysplasia.

[Association of single nucleotide polymorphisms of cytochrome P450 gene with susceptibility to gout in ethnic Han males from coastal regions of Shandong province].

OBJECTIVE: To assess the association of cytochrome P450 gene single nucleotide polymorphisms (SNPs) with susceptibility to gout in ethnic Han males from coastal regions of Shandong province. METHODS: Four hundred and eighty male patients with gout and 480 healthy male controls were included. Genotyping was carried out with a custom Illumina GoldenGate Genotyping assay to detect SNP rs2275620 of CYP2C8 gene, SNP rs2070676 of CYP2E1 gene, SNP rs837395 of CYP4B1 gene, and SNP rs194150 of TBXAS1 gene. The association was assessed with chi-square test. RESULTS: No significant difference has been found between the two groups in regard to the genotypic and allelic frequencies of the TT, AT, AA genotypes and A, T alleles of the SNP rs2275620 of the CYP2C8 gene (P=0.88; P=0.97), the CC, CG, GG genotypes and C,G alleles of SNP rs2070676 of the CYP2E1 gene (P=0.24; P=0.09), the TT, AT, AA genotypes and A, T alleles of SNP rs837395 of the CYP4B1 (P=0.88; P=0.97), and TT, AT, AA genotypes and the A,T alleles of SNP rs194150 of TBXAS1 gene (P=0.15; P=0.06). CONCLUSION: This study has identified no association of SNP loci rs2275620(A/T) of CYP2C8, rs2070676(C/G) of CYP2E1, rs837395(A/T) of CYP4B1 and rs194150(A/T) of TBXAS1 with gout in ethnic Han males from coastal regions in Shandong province. However, our result needs to be replicated in larger sets of patients collected from other regions and populations.

Downregulation of TBXAS1 in an iron-induced malignant mesothelioma model.

Malignant mesothelioma is an aggressive and therapy-resistant neoplasm arising from mesothelial cells. Evidence suggests that the major pathology associated with asbestos-induced mesothelioma is local iron overload. In the present study, we induced iron-induced mesothelioma in rats based on previous reports. Ten Wistar rats were given ferric saccharate and nitrilotriacetate i.p. for 5 days a week. Five of the ten rats exhibited widespread mesotheliomas in the peritoneum and tunica vaginalis. The tumor cells showed positive immunostaining for calretinin, wilms tumor-1, podoplanin and the oxidative DNA marker 8-hydroxy-2'-deoxyguanosine. In three of the five rats with mesothelioma, array-based comparative genomic hybridization analysis identified a common chromosomal deletion mapped to the chromosomal 4q31 locus, which encompasses the TBXAS1 gene. Downregulation of the TBXAS1 gene was confirmed using quantitative PCR. TBXAS1 gene expression was also reduced in three of four human malignant pleural mesothelioma cell lines compared with normal bronchial epithelial cells. Immunohistochemistry revealed that TBXAS1 expression was weakly positive and positive in five and three out of eight human malignant mesothelioma samples, respectively. In conclusion, TBXAS1 gene expression was downregulated in rats with iron-induced mesothelioma. The relationship between iron overload and TBXAS1 downregulation should be pursued further.