The anticancer human mTOR inhibitor sapanisertib potently inhibits multiple Plasmodium kinases and life cycle stages.

Compounds acting on multiple targets are critical to combating antimalarial drug resistance. Here, we report that the human "mammalian target of rapamycin" (mTOR) inhibitor sapanisertib has potent prophylactic liver stage activity, in vitro and in vivo asexual blood stage (ABS) activity, and transmission-blocking activity against the protozoan parasite Plasmodium spp. Chemoproteomics studies revealed multiple potential Plasmodium kinase targets, and potent inhibition of Plasmodium phosphatidylinositol 4-kinase type III beta (PI4Kß) and cyclic guanosine monophosphate-dependent protein kinase (PKG) was confirmed in vitro. Conditional knockdown of PI4Kß in ABS cultures modulated parasite sensitivity to sapanisertib, and laboratory-generated P. falciparum sapanisertib resistance was mediated by mutations in PI4Kß. Parasite metabolomic perturbation profiles associated with sapanisertib and other known PI4Kß and/or PKG inhibitors revealed similarities and differences between chemotypes, potentially caused by sapanisertib targeting multiple parasite kinases. The multistage activity of sapanisertib and its in vivo antimalarial efficacy, coupled with potent inhibition of at least two promising drug targets, provides an opportunity to reposition this pyrazolopyrimidine for malaria.

Reaction hijacking of tyrosine tRNA synthetase as a new whole-of-life-cycle antimalarial strategy.

Aminoacyl transfer RNA (tRNA) synthetases (aaRSs) are attractive drug targets, and we present class I and II aaRSs as previously unrecognized targets for adenosine 5'-monophosphate-mimicking nucleoside sulfamates. The target enzyme catalyzes the formation of an inhibitory amino acid-sulfamate conjugate through a reaction-hijacking mechanism. We identified adenosine 5'-sulfamate as a broad-specificity compound that hijacks a range of aaRSs and ML901 as a specific reagent a specific reagent that hijacks a single aaRS in the malaria parasite Plasmodium falciparum, namely tyrosine RS (PfYRS). ML901 exerts whole-life-cycle-killing activity with low nanomolar potency and single-dose efficacy in a mouse model of malaria. X-ray crystallographic studies of plasmodium and human YRSs reveal differential flexibility of a loop over the catalytic site that underpins differential susceptibility to reaction hijacking by ML901.

Targeted Covalent Inhibition of Plasmodium FK506 Binding Protein 35.

FK506-binding protein 35, FKBP35, has been implicated as an essential malarial enzyme. Rapamycin and FK506 exhibit antiplasmodium activity in cultured parasites. However, due to the highly conserved nature of the binding pockets of FKBPs and the immunosuppressive properties of these drugs, there is a need for compounds that selectively inhibit FKBP35 and lack the undesired side effects. In contrast to human FKBPs, FKBP35 contains a cysteine, C106, adjacent to the rapamycin binding pocket, providing an opportunity to develop targeted covalent inhibitors of Plasmodium FKBP35. Here, we synthesize inhibitors of FKBP35, show that they directly bind FKBP35 in a model cellular setting, selectively covalently modify C106, and exhibit antiplasmodium activity in blood-stage cultured parasites.

Phosphatidylinositol 3-phosphate and Hsp70 protect Plasmodium falciparum from heat-induced cell death.

Phosphatidylinositol 3-phosphate (PI(3)P) levels in Plasmodium falciparum correlate with tolerance to cellular stresses caused by artemisinin and environmental factors. However, PI(3)P function during the Plasmodium stress response was unknown. Here, we used PI3K inhibitors and antimalarial agents to examine the importance of PI(3)P under thermal conditions recapitulating malarial fever. Live cell microscopy using chemical and genetic reporters revealed that PI(3)P stabilizes the digestive vacuole (DV) under heat stress. We demonstrate that heat-induced DV destabilization in PI(3)P-deficient P. falciparum precedes cell death and is reversible after withdrawal of the stress condition and the PI3K inhibitor. A chemoproteomic approach identified PfHsp70-1 as a PI(3)P-binding protein. An Hsp70 inhibitor and knockdown of PfHsp70-1 phenocopy PI(3)P-deficient parasites under heat shock. Furthermore, PfHsp70-1 downregulation hypersensitizes parasites to heat shock and PI3K inhibitors. Our findings underscore a mechanistic link between PI(3)P and PfHsp70-1 and present a novel PI(3)P function in DV stabilization during heat stress.

Genetic association analysis of CIITA variations with nasal polyp pathogenesis in asthmatic patients.

Nasal polyps are abnormal lesions arising mainly from the nasal mucosa and paranasal sinuses. Since the human class II, major histocompatibility complex, transactivator (CIITA) is a positive regulator of class II, major histocompatibility complex gene transcription, the CIITA gene is thought to be involved in the presence of nasal polyps in asthma and aspirin hypersensitive patients. To investigate the association between CIITA and nasal polyposis, 18 single nucleotide polymorphisms (SNPs) were genotyped in 467 asthmatics who were classified into 158 aspirin-exacerbated respiratory disease (AERD) and 309 aspirin-tolerant asthma (ATA) subgroups. Differences in the frequency distribution of CIITA variations between polyp-positive cases and polyp-negative controls were determined using logistic analyses. Initially, a total of 9 CIITA variants were significantly associated with the presence of nasal polyps in the overall asthma, AERD and ATA groups [P=0.001-0.05, odds ratio (OR)=0.53-2.35 in the overall asthma group; P=0.01-0.02, OR=2.45-2.66 in the AERD group; P=0.001­0.05, OR=0.45-2.61 in the ATA group using various modes of genetic inheritance]. One the variations (rs12932187) retained this association after multiple testing corrections (Pcorr=0.01) in the overall asthma group. In addition, two variations (rs12932187 and rs11074938) were associated with the presence of nasal polyps following multiple testing corrections (Pcorr=0.02 and 0.04, respectively) in the ATA group. These novel findings suggest that rs12932187 and rs11074938 may constitute susceptibility markers of inflammation of the nasal passages in asthma patients.

Potential association between ANXA4 polymorphisms and aspirin-exacerbated respiratory disease.

Aspirin-exacerbated respiratory disease (AERD) is a clinical syndrome characterized by bronchoconstriction after ingestion of nonsteroidal anti-inflammatory drugs including aspirin. The Ca concentration in bronchial epithelial cells is an important factor for bronchoconstriction. Human annexin A4 (ANXA4) is predominantly expressed in the secretory epithelia in the lung, stomach, intestine, and kidney. Furthermore, translocation and induction of ANXA4 have been observed in human Ca-depleted neutrophils. To investigate the association between annexin A4 polymorphisms and the risk of AERD, we have genotyped 21 variants from 102 AERD subjects and 429 aspirin-tolerant asthma (ATA) controls. Logistic analyses controlling for sex, smoking status, and atopy as covariates were performed to estimate the association between the annexin A4 polymorphisms and AERD. Among these variants, 8 polymorphisms (rs2168116, rs4853017, rs6546547, rs13428251, rs7577864, rs7559354, rs7588022, and rs3816491) and 2 haplotypes (ANXA4-ht3 and ANXA4-ht5) were significantly associated with the risk of AERD. One common polymorphism in intron 11, rs3816491, showed the strongest association signal with susceptibility to aspirin-AERD even after multiple testing corrections (OR=0.57; 95% confidence interval 0.40-0.83; P=0.003; P=0.045 in the codominant model). Although further functional evaluations of replication studies in larger cohorts are required, our findings suggest that the annexin A4 could have susceptibility for AERD.

Association study of genetic variations in microRNAs with the risk of hepatitis B-related liver diseases.

BACKGROUND AND AIMS: MicroRNAs have been recently identified as important regulators that influence human carcinogenesis, cancer progression, and the interaction between the host and virus. This study investigates an association between microRNAs (miR-101-1, miR-101-2, and miR-338) and the risk of liver diseases through clearance of hepatitis B virus infection, development of liver cirrhosis, and hepatocellular carcinoma occurrence. METHODS: Genetic variations were genotyped using the TaqMan assay in 1439 Korean hepatitis B virus patients. To investigate the relationship between four polymorphisms in three microRNAs and the disease phenotypes, differences in frequency distribution of variations were analysed using logistic and multiple regression analyses after adjusting for age and gender as covariates. RESULTS: We find that the rs7536540 polymorphism in miR-101-1 is significantly associated with development of liver cirrhosis and hepatocellular carcinoma occurrence. In addition, rs12375841 and its unique haplotype (ht2) in miR-101-2 show significant association with clearance of hepatitis B virus infection. CONCLUSIONS: To our knowledge, this is the first study to examine a relationship between the three microRNA genes and the risk of hepatitis B-related liver diseases. We expect that the findings in this study will be helpful to further genetic studies in the pathophysiology of hepatitis B virus-related liver diseases.

Genetic association analysis of ERBB4 polymorphisms with the risk of schizophrenia and SPEM abnormality in a Korean population.

The human receptor tyrosine-protein kinase erbB-4 (ERBB4) gene mediates neuregulin 1 (NRG1) signaling, and is involved in neuronal migration and differentiation. Despite the potential significance of ERBB4 in the development of schizophrenia, relatively few genetic studies for the association of ERBB4 with schizophrenia were performed in the populations including Ashkenazi Jews, Americans including Caucasians and African Americans, and Han Chinese. In this study, differences in ERBB4 variations were investigated to determine association with schizophrenia and smooth pursuit eye movement (SPEM) abnormality in a Korean population. Seven polymorphisms in ERBB4 gene were genotyped in 435 schizophrenia cases and 390 unrelated healthy controls. In order to investigate the relationship between ERBB4 and the risk of schizophrenia and SPEM abnormality, differences in SNP and haplotype distribution were analyzed using logistic and multiple regression analyses. However, we failed to replicate the associations reported by previous studies in other populations. Although statistically not significant, the tendency towards associations between ERBB4 polymorphisms and the risk of schizophrenia and SPEM abnormality in this study from a Korean population would be helpful for further genetic etiology studies in schizophrenia.

Potential association of DDR1 genetic variant with FEV1 decline by aspirin provocation in asthmatics.

BACKGROUND: The discoidin domain receptor tyrosine kinase 1 (DDR1) is positioned within the major histocompatibility complex (MHC) region which plays an important role in the immune system. In addition, DDR1 has been elucidated to be downregulated during the epithelial-mesenchymal transition of bronchial epithelium. OBJECTIVE: To investigate the potential genetic associations between DDR1 and aspirin-exacerbated respiratory disease (AERD), this study conducted association studies of DDR1 single nucleotide polymorphisms (SNPs) with AERD and the obstructive symptom of forced expiratory volume in 1 s (FEV(1)) decline after aspirin provocation. METHODS: Nine common SNPs were genotyped in 93 AERD patients and 96 aspirin-tolerant asthma (ATA) controls. The genotype distributions of all loci were in Hardy-Weinberg equilibrium (HWE; p > .05). Results. In the results of logistic analyses using age, sex, smoking status, and atopy as covariates, DDR1 rs1264320 in the intronic region showed a potent association signal with FEV(1) decline by aspirin provocation in asthmatics of this study even after corrections for multiple testing (p = .003 and corrected p = .01). However, the variants of DDR1 were not significantly associated with the AERD development (corrected p > .05). On further comparison of FEV(1) decline by aspirin provocation between AERD and ATA, the variant rs1264320 was found to be associated with the FEV(1) decline of ATA rather than AERD. CONCLUSION: Despite the need for further functional evaluations and replications, we conclude that DDR1 polymorphisms are not likely to contribute to predispositions of AERD, but may be potentially associated with FEV(1) decline by aspirin provocation in asthmatics.

HLA-DRA polymorphisms associated with risk of nasal polyposis in asthmatic patients.

BACKGROUND: Nasal polyps, part of the aspirin triad symptoms, are edematous protrusions arising from the mucosa of the nasal sinuses. Although the causative factors and pathogenesis of the polyps are unknown, the significant effect of human leukocyte antigen-DR (HLA-DR) expression in nasal polyps and genetic associations of the major histocompatibility complex class II, DR alpha (HLA-DRA) with immune-mediated diseases have been revealed. METHODS: To investigate the associations of HLA-DRA polymorphisms with nasal polyposis in asthmatic patients and in aspirin-hypersensitive subgroups, 22 single nucleotide polymorphisms (SNPs) were genotyped in a total of 467 asthmatic patients including 158 nasal polyp-positive and 309 polyp-negative subjects. RESULTS: Statistical analysis showed that four SNPs (p = 0.0005-0.02; Pcorr = 0.009-0.033) and one haplotype (p = 0.002; Pcorr = 0.029) were significantly associated with the presence of nasal polyposis in asthmatic patients. In further analysis, although significant signals disappeared after corrections for multiple testing, two HLA-DRA polymorphisms (rs9268644C>A, rs3129878A>C) were found to be potential markers for nasal polyp development in aspirin-tolerant asthma (p = 0.005 and 0.007, respectively) compared with the aspirin-exacerbated respiratory disease (p > 0.05) subgroup. In silico analysis predicted major "C" allele of rs14004C>A in 5'-untranslated region as a potential binding site for regulatory glucocorticoid receptor. In addition, sequence nearby rs1051336G>A is suspected to be a pyrimidine-rich element that affects mRNA stability. CONCLUSION: Despite the need for replication in larger cohorts and/or functional evaluations, our findings suggest that HLA-DRA polymorphisms might contribute to nasal polyposis susceptibility in patients with asthma.

Association study between TRIM26 polymorphisms and risk of aspirin-exacerbated respiratory disease.

Aspirin-exacerbated respiratory disease (AERD) is a clinical syndrome that is characterized by nasal polyposis, general symptoms of asthma and sensitive response to non-steroidal anti-inflammatory drugs (NSAIDs). Although the exact function of tripartite motif-containing 26 (TRIM26) still remains unknown, the gene functions in the immune response. Thus, we hypothesized that TRIM26 polymorphisms may affect aspirin-induced bronchospasm and explored whether the gene can be a marker for diagnosis of AERD. To investigate our hypothesis that TRIM26 may serve as a genetic marker for diagnosis of AERD, this study focused on demonstrating the associations between single nucleotide polymorphisms (SNPs) of the TRIM26 gene and AERD. We genotyped 18 polymorphisms of TRIM26 in a total of 189 asthmatics and examined their associations with the risk of AERD. We performed logistic analysis for obtaining P-values and regression analysis for demonstrating an association between the phenotype with FEV1 and the genotype. We observed no associations between polymorphisms in TRIM26 and the risk of AERD in both logistic and regression analyses. Although our results reveal a lack of association, the suggested functional role of TRIM26 makes it a putative candidate gene for AERD. Thus, replications in other populations using larger samples may provide valuable information for AERD etiology.

DCBLD2 gene variations correlate with nasal polyposis in Korean asthma patients.

BACKGROUND: Nasal polyps are abnormal lesions that cause airway obstruction and can occur along with other respiratory diseases. On account of its association with aspirin exacerbated respiratory disease (AERD), the human discoidin, CUB and LCCL domain containing 2 (DCBLD2) is hypothesized to be a candidate gene for the development of nasal polyps in asthma patients. METHODS: A total of 12 single-nucleotide polymorphisms (SNPs) were genotyped in 467 Korean asthma patients who were stratified further into 108 AERD and 353 aspirin-tolerant asthma (ATA) subgroups. Five major haplotypes were inferred from pairwise comparison of the polymorphisms. The patients were matched to control for confounds, and differences in the frequency distribution of DCBLD2 SNPs and haplotypes were analyzed using logistic models via various modes of genetic inheritance. RESULTS: Results reveal significant association of rs828618 and DCBLD2_ht1 with nasal polyposis in the overall asthma patients group (P = 0.006, P(corr) = 0.05). Interestingly, the strength of association were maintained in the ATA subgroup (P = 0.007, P(corr) = 0.06), and moderate correlation was detected in the AERD subgroup (P = 0.04-0.05, P(corr) > 0.05). CONCLUSIONS: Although further replication and validation are needed, these findings suggest that DCBLD2 could be a potential marker and drug target for treatment of nasal polyposis in Korean asthma patients.

Possible role of EMID2 on nasal polyps pathogenesis in Korean asthma patients.

BACKGROUND: Since subepithelial fibrosis and protruded extracellular matrix are among the histological characteristics of polyps, the emilin/multimerin domain-containing protein 2 (EMID2) gene is speculated to be involved in the presence of nasal polyps in asthma and aspirin-hypersensitive patients. METHODS: To investigate the association between EMID2 and nasal polyposis, 49 single-nucleotide polymorphisms (SNPs) were genotyped in 467 asthmatics of Korean ancestry who were stratified further into 114 aspirin exacerbated respiratory disease (AERD) and 353 aspirin-tolerant asthma (ATA) subgroups. From pairwise comparison of the genotyped polymorphisms, 14 major haplotypes (frequency > 0.05) were inferred and selected for association analysis. Differences in the frequency distribution of EMID2 variations between polyp-positive cases and polyp-negative controls were determined using logistic analyses. RESULTS: Initially, 13 EMID2 variants were significantly associated with the presence of nasal polyps in the overall asthma group (P = 0.0008-0.05, OR = 0.54-1.32 using various modes of genetic inheritance). Although association signals from 12 variants disappeared after multiple testing corrections, the relationship between EMID2_BL1_ht2 and nasal polyposis remained significant via a codominant mechanism (P corr = 0.03). On the other hand, the nominal associations observed between the genetic variants tested for the presence of nasal polyps in AERD (P = 0.003-0.05, OR = 0.25-1.82) and ATA (P = 0.01-0.04, OR = 0.46-10.96) subgroups disappeared after multiple comparisons, suggesting lack of associations. CONCLUSIONS: These preliminary findings suggest that EMID2_BL1_ht2 may be a susceptibility marker of inflammation of the nasal passages among Korean asthma patients.

Association of FANCC polymorphisms with FEV1 decline in aspirin exacerbated respiratory disease.

Aspirin exacerbated respiratory disease (AERD) is a clinical condition characterized by severe decline in forced expiratory volume in one second (FEV1) following the ingestion of non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin. The exacerbated inflammatory response in Fancc-deficient mice has been reported to be associated with hemopoietic responses that are also related to AERD pathogenesis. To investigate associations of FANCC polymorphisms with AERD and related phenotypes, this study genotyped 25 common single nucleotide polymorphisms (SNPs) in a total of 592 Korean asthmatics including 163 AERD and 429 aspirin-tolerant asthma (ATA) subjects. Logistic analysis revealed that genetic polymorphisms of the FANCC gene might not be directly related to AERD development and nasal polyposis (P > 0.05). However, the FEV1 decline by aspirin provocation showed significant associations with FANCC polymorphisms (P = 0.006-0.04) and a haplotype (unique to rs4647416G > A, P = 0.01 under co-dominant, P = 0.006 under recessive model). In silico analysis showed that the "A" allele of rs4647376C > A, which was more prevalent in AERD than in ATA, could act as a potential branch point (BP) site for alternative splicing (BP score = 4.16). Although replications in independent cohorts and further functional evaluations are still needed, our preliminary findings suggest that FANCC polymorphisms might be associated with the obstructive symptoms in allergic diseases.

Lack of association of RAD51 genetic variations with hepatitis B virus clearance and occurrence of hepatocellular carcinoma in a Korean population.

The RecA homolog, E. coli (S. cerevisiae) (RAD51) may modulate hepatitis B virus (HBV) infection by maintaining genome integrity and mediating homologous DNA repairs. In this study, 16 sequence variations were detected by resequencing all exons, the exon-intron boundary, and promoter regions of the human RAD51 gene in DNA samples of 24 unrelated individuals. To investigate the association of common variations in the RAD51 locus with HBV infection and hepatocellular carcinoma (HCC) occurrence, six common polymorphisms were genotyped in a total of 1,103 Korean HBV cohort, composed of 433 spontaneously recovered patients as controls and 670 chronic carriers of HBV, who were stratified further into 327 cirrhosis/chronic hepatitis patients and 343 patients with HCC infected with HBV. Logistic analyses revealed no significant association of RAD51 polymorphisms and haplotypes with HBV clearance and HCC occurrence (P > 0.05). Furthermore, with age of infection as an important factor in disease progression to HCC, results from the Cox proportional hazards analysis showed no significant associations between any of the tested RAD51 variants and the age of onset of HCC (P > 0.05), suggesting that genetic polymorphisms of RAD51 may not play an important role in clearance of HBV and disease progression to HCC. Although studies in other populations are needed to confirm these findings, this preliminary data may contribute to the current knowledge on the pathogenesis of hepatitis.

UBE3C genetic variations as potent markers of nasal polyps in Korean asthma patients.

The human ubiquitin protein ligase E3C (UBE3C) regulates airway inflammatory responses and is hypothesized to be associated with the presence of nasal polyps in asthma-related diseases. A total of 24 UBE3C single-nucleotide polymorphisms (SNPs) were genotyped in a 467 Korean asthma cohort that was stratified into more homogenous phenotypes of 114 aspirin-exacerbated respiratory disease subgroup and 353 aspirin-tolerant asthma (ATA) subjects. Association analysis revealed that 16 UBE3C SNPs were significantly associated with presence of nasal polyps in the overall asthma group (P=0.0008 and P(corr)=0.01; odds ratio (OR)=0.60). The strength of association from 10 polymorphisms was increased in the ATA subgroup (P=0.0002 and P(corr)=0.003; OR=0.49). In addition, UBE3C_ht1 was found to be consistently associated with nasal polyps in the overall asthmatics group (P=0.006) and the ATA phenotype (P=0.002; P(corr)=0.02) via a codominant mechanism. Our findings provide evidence that variations in UBE3C are potent genetic markers of nasal polyps development in Korean asthmatics and may contribute novel insights into the clinical relevance and potential involvement of UBE3C in respiratory deficiencies.

TGFBR3 polymorphisms and its haplotypes associated with chronic hepatitis B virus infection and age of hepatocellular carcinoma occurrence.

OBJECTIVE: Hepatocellular carcinoma (HCC) is one of the most common cancers and is mainly caused by viral infections including hepatitis B virus (HBV). Recently, the decreased expression level of the transforming growth factor, beta receptor III (TGFBR3) gene, has been implicated in HCC and other human cancers. This study investigated whether TGFBR3 polymorphisms might be associated with HBV clearance and HCC occurrence. METHODS: This study identified 27 single nucleotide polymorphisms (SNPs) in the exon, promoter, and exon-intron boundary regions of TGFBR3 by resequencing in 24 individuals. Then, 9 SNPs in the promoter and exons of the gene were genotyped from 1,065 Koreans composed of 637 chronic carriers (CC) and 428 spontaneously recovered (SR) subjects. RESULTS: Two SNPs, rs1805113 (Phe676Phe) in exon 13 and rs1805117 in 3'-UTR (p = 0.009 and p = 0.008, respectively) were significantly associated with HBV clearance. In addition, Cox relative hazards analyses revealed that haplotype BL2_ht2 showed a significant association with the age of HCC occurrence among chronic HBV patients (relative hazard = 1.38; p = 0.007). CONCLUSION: Our findings suggest that TGFBR3 polymorphisms and its haplotypes might be associated with HBV clearance and age of HCC occurrence.

Lack of association between CD58 genetic variations and aspirin-exacerbated respiratory disease in a Korean population.

BACKGROUND: Exacerbation of asthma symptoms due to aspirin ingestion may lead to life-threatening lung failure. The adhesion molecule CD58 gene may play a crucial role in aspirin-exacerbated respiratory disease (AERD) pathogenesis by mediating the biological functions of asthma-inducing mechanisms including T helper cells, proinflammatory cytokines, and natural killer T cells. OBJECTIVE: This study aimed to investigate the association of CD58 variations with aspirin-induced bronchospasm in Korean asthma patients. METHODS: Seven single-nucleotide polymorphisms were selected for genotyping based on previously reported polymorphisms in the International HapMap database. Genotyping was carried out using TaqMan assay and 2 major haplotypes were obtained in 163 AERD cases and 429 aspirin-tolerant asthma controls. Frequency distributions of CD58 variations were analyzed using logistic and regression models. RESULTS: Results showed that none of the analyzed CD58 single-nucleotide polymorphisms and haplotypes was significantly associated with AERD development and fall rate of FEV(1) by aspirin provocation, an important diagnostic marker of aspirin hypersensitivity. CONCLUSIONS: This preliminary study suggests that CD58 does not affect AERD susceptibility in a Korean population, and may provide a new direction for future disease etiology.

Association analysis of C6 genetic variations and aspirin hypersensitivity in Korean asthmatic patients.

There has been increasing evidence that genetic mechanisms contribute to the development of aspirin-intolerant asthma (AIA), a life-threatening disease. The complement component (C6) is a constituent of a biochemical cascade that has been implicated in airway epithelial damage and nasal polyposis, and therefore, may be a risk factor for AIA. To investigate the association between C6 variations and AIA in a Korean asthma cohort, 27 SNPs were selected for genotyping based on previously reported polymorphisms in the HapMap database. Genotyping was carried out using TaqMan assay, and five major haplotypes were obtained in 163 AIA cases and 429 aspirin-tolerant asthma (ATA) controls subjects. Genotype frequency distributions of C6 polymorphisms and haplotypes were analyzed using logistic and regression models. Subsequent analyses revealed a lack of association between C6 genetic variations and AIA. From the initial analyses, marginal associations of rs10512766 (p = 0.04 in co-dominant model) and rs4957374 (p = 0.05 in dominant model) with AIA did not reach the threshold of significance after multiple testing corrections; thus this study failed to find convincing evidence that variations in C6 gene influence the risk of AIA in a Korean population. However, these preliminary results may contribute to the etiology of aspirin hypersensitivity in Korean asthmatic patients.

Association analysis of DTD1 gene variations with aspirin-intolerance in asthmatics.

Aspirin ingestion is a common precipitating factor of life-threatening asthma attacks, requiring some patients to undergo mechanical ventilation. The gene, D-tyrosyl-tRNA deacylase 1 (DTD1), may be a risk factor for aspirin-intolerant asthma (AIA) by catalyzing the hydrolysis of D-tryptophan and interacting with the tyrosyl-tRNA synthetase (tyrRS) enzyme, which promotes a pro-inflammatory phenotype. In order to investigate the association of DTD1 variants with the risk of AIA in an asthma cohort, 38 single nucleotide polymorphisms (SNPs) were genotyped and 5 major haplotypes were obtained in 163 AIA cases and 429 aspirin-tolerant asthma (ATA) controls. Differences in DTD1 SNP and haplotype distributions were analyzed using logistic and multiple regression models and were adjusted for age, gender, smoking status, atopy and body mass index (BMI) as covariates. Subsequent analyses revealed no association between DTD1 variants and the risk of AIA. Although nominal evidence of an association was detected between several DTD1 variants and the rate of decline of the forced expiratory volume in the first second (FEV1) in AIA patients (rs6136444, rs6136469, rs6081338 and DTD1_ht5; P=0.01-0.02), the signals reached the threshold of multiple testing corrections, suggesting that DTD1 variants do not affect the abnormalities of the upper airways in AIA patients.