Advances in methylation analysis of liquid biopsy in early cancer detection of colorectal and lung cancer.

Methylation patterns in cell-free DNA (cfDNA) have emerged as a promising genomic feature for detecting the presence of cancer and determining its origin. The purpose of this study was to evaluate the diagnostic performance of methylation-sensitive restriction enzyme digestion followed by sequencing (MRE-Seq) using cfDNA, and to investigate the cancer signal origin (CSO) of the cancer using a deep neural network (DNN) analyses for liquid biopsy of colorectal and lung cancer. We developed a selective MRE-Seq method with DNN learning-based prediction model using demethylated-sequence-depth patterns from 63,266 CpG sites using SacII enzyme digestion. A total of 191 patients with stage I-IV cancers (95 lung cancers and 96 colorectal cancers) and 126 noncancer participants were enrolled in this study. Our study showed an area under the receiver operating characteristic curve (AUC) of 0.978 with a sensitivity of 78.1% for colorectal cancer, and an AUC of 0.956 with a sensitivity of 66.3% for lung cancer, both at a specificity of 99.2%. For colorectal cancer, sensitivities for stages I-IV ranged from 76.2 to 83.3% while for lung cancer, sensitivities for stages I-IV ranged from 44.4 to 78.9%, both again at a specificity of 99.2%. The CSO model's true-positive rates were 94.4% and 89.9% for colorectal and lung cancers, respectively. The MRE-Seq was found to be a useful method for detecting global hypomethylation patterns in liquid biopsy samples and accurately diagnosing colorectal and lung cancers, as well as determining CSO of the cancer using DNN analysis.Trial registration: This trial was registered at ClinicalTrials.gov (registration number: NCT04253509) for lung cancer on 5 February 2020, https://clinicaltrials.gov/ct2/show/NCT04253509 . Colorectal cancer samples were retrospectively registered at CRIS (Clinical Research Information Service, registration number: KCT0008037) on 23 December 2022, https://cris.nih.go.kr , https://who.init/ictrp . Healthy control samples were retrospectively registered.

Transferability of Alzheimer Disease Polygenic Risk Score Across Populations and Its Association With Alzheimer Disease-Related Phenotypes.

Importance: Polygenic risk scores (PRSs), which aggregate the genetic effects of single-nucleotide variants identified in genome-wide association studies (GWASs), can help distinguish individuals at a high genetic risk for Alzheimer disease (AD). However, genetic studies have predominantly focused on populations of European ancestry. Objective: To evaluate the transferability of a PRS for AD in the Korean population using summary statistics from a prior GWAS of European populations. Design, Setting, and Participants: This cohort study developed a PRS based on the summary statistics of a large-scale GWAS of a European population (the International Genomics of Alzheimer Project; 21 982 AD cases and 41 944 controls). This PRS was tested for an association with AD dementia and its related phenotypes in 1634 Korean individuals, who were recruited from 2013 to 2019. The association of a PRS based on a GWAS of a Japanese population (the National Center for Geriatrics and Gerontology; 3962 AD cases and 4074 controls) and a transancestry meta-analysis of European and Japanese GWASs was also evaluated. Data were analyzed from December 2020 to June 2021. Main Outcomes and Measures: Risk of AD dementia, amnestic mild cognitive impairment (aMCI), earlier symptom onset, and amyloid ß deposition (Aß). Results: A total of 1634 Korean patients (969 women [59.3%]), including 716 individuals (43.6%) with AD dementia, 222 (13.6%) with aMCI, and 699 (42.8%) cognitively unimpaired controls, were analyzed in this study. The mean (SD) age of the participants was 71.6 (9.0) years. Higher PRS was associated with a higher risk of AD dementia independent of APOE ɛ4 status in the Korean population (OR, 1.95; 95% CI, 1.40-2.72; P < .001). Furthermore, PRS was associated with aMCI, earlier symptom onset, and Aß deposition independent of APOE ɛ4 status. The PRS based on a transancestry meta-analysis of data sets comprising 2 distinct ancestries showed a slightly improved accuracy. Conclusions and Relevance: In this cohort study, a PRS derived from a European GWAS identified individuals at a high risk for AD dementia in the Korean population. These findings emphasize the transancestry transferability and clinical value of PRSs and suggest the importance of enriching diversity in genetic studies of AD.

A Genome-Wide Association Study and Machine-Learning Algorithm Analysis on the Prediction of Facial Phenotypes by Genotypes in Korean Women.

Purpose: Changes in facial appearance are affected by various intrinsic and extrinsic factors, which vary from person to person. Therefore, each person needs to determine their skin condition accurately to care for their skin accordingly. Recently, genetic identification by skin-related phenotypes has become possible using genome-wide association studies (GWAS) and machine-learning algorithms. However, because most GWAS have focused on populations with American or European skin pigmentation, large-scale GWAS are needed for Asian populations. This study aimed to evaluate the correlation of facial phenotypes with candidate single-nucleotide polymorphisms (SNPs) to predict phenotype from genotype using machine learning. Materials and Methods: A total of 749 Korean women aged 30-50 years were enrolled in this study and evaluated for five facial phenotypes (melanin, gloss, hydration, wrinkle, and elasticity). To find highly related SNPs with each phenotype, GWAS analysis was used. In addition, phenotype prediction was performed using three machine-learning algorithms (linear, ridge, and linear support vector regressions) using five-fold cross-validation. Results: Using GWAS analysis, we found 46 novel highly associated SNPs (p < 1×10-05): 3, 20, 12, 6, and 5 SNPs for melanin, gloss, hydration, wrinkle, and elasticity, respectively. On comparing the performance of each model based on phenotypes using five-fold cross-validation, the ridge regression model showed the highest accuracy (r2 = 0.6422-0.7266) in all skin traits. Therefore, the optimal solution for personal skin diagnosis using GWAS was with the ridge regression model. Conclusion: The proposed facial phenotype prediction model in this study provided the optimal solution for accurately predicting the skin condition of an individual by identifying genotype information of target characteristics and machine-learning methods. This model has potential utility for the development of customized cosmetics.

Clinical Utility of Combined Circulating Tumor Cell and Circulating Tumor DNA Assays for Diagnosis of Primary Lung Cancer.

BACKGROUND/AIM: Although it has been suggested that circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA) might be used in a complementary manner in lung cancer diagnosis, limited confirmatory data are available. In this prospective study, we evaluated the diagnostic performance of each assay separately and in combination. PATIENTS AND METHODS: From March 2018 to January 2019, patients with suspected primary lung cancer, who underwent routine lung cancer work-up and peripheral blood sampling, were prospectively enrolled in the study. Epithelial cell adhesion molecule and cytokeratin served as markers of CTCs. In terms of ctDNA analysis, single-nucleotide variants were evaluated via next-generation sequencing. RESULTS: We analyzed 111 patients, including 99 with primary lung cancer and 12 with benign pulmonary disease. The median number of CTCs in 10 ml of blood was 3. The most frequently detected single nucleotide variants of ctDNA were TP53, CDKN2A, and EGFR. The diagnostic sensitivity of conventional tumor marker (combination of carcinoembryonic antigen/CYFRA 21-1/neuron-specific enolase) was 66.7%, while those of the ctDNA and CTC assays were 72.7% and 65.7%, respectively. The sensitivity of the CTC/ctDNA combination (95.0%) was significantly greater than those of the CTC (p<0.001), ctDNA (p<0.001), or conventional tumor marker (p<0.001) alone. Subgroup analysis revealed that the sensitivity of the combination assay was greater than those of the CTC or ctDNA assays alone, regardless of tumor stage or histopathology type. CONCLUSION: The CTC/ctDNA combination assay enhanced the sensitivity of primary lung cancer diagnosis. The combination assay strategy may be clinically useful and could enhance the early detection of lung cancer (ClinicalTrials.gov number: NCT03479099).

Erratum: Prevalence of germline BRCA mutations among women with carcinoma of the peritoneum or fallopian tube.

This corrects the article on p. e43 in vol. 29, PMID: 29770616.

Prevalence of germline BRCA mutations among women with carcinoma of the peritoneum or fallopian tube.

OBJECTIVE: The aim of the present study was to assess the frequency of germline mutations in patients with peritoneal carcinoma (PC) or the fallopian tube carcinoma (FTC), using a multi-gene panel. METHODS: Twenty-six patients diagnosed with either PC or FTC between January 2013 and December 2016 were recruited consecutively. Germline DNA was sequenced using a 6-gene next generation sequencing (NGS) panel following genetic counseling. Surgico-medical information was obtained from hospital records. Genetic variations were detected using the panel and were cross-validated by Sanger direct sequencing. RESULTS: Germline BRCA1/2 mutations were identified in 6 patients (23.1%). Four were detected in patients with PC and 2 were in FTC patients. No mutations were detected in TP53, PTEN, CDH1, or PALB2. We identified 11 variant of uncertain significance (VUS) in 9 patients; 2 in BRCA1, 3 in BRCA2, 2 in TP53, and 4 in CDH1. We also detected a CDH1 c.2164+16->A VUS in 3 patients. CONCLUSION: The prevalence of germline BRCA1/2 mutations in patients with PC or FTC is comparable to that of BRCA1/2 mutations in epithelial ovarian cancer patients.

Emerging Targets to Relieve Fat Stress-Induced Liver Diseases: UDCA, Tocotrienol, ω-3 PUFAs, and IgY Targeted NPC1L1 Cholesterol Transporter.

Fat stress-induced liver disease is a hepatic manifestation of metabolic syndrome initiated by excess fat accumulation and encompasses a wide spectrum of diseases from non-alcoholic fatty liver disease to nonalcoholic steatohepatitis, a precursor lesion progressing to more aggressive liver cirrhosis and hepatocellular carcinoma. Although the incidence of these fat stress-induced liver diseases is rapidly increasing worldwide in parallel with the growing epidemics of obesity and metabolic diseases, its exact pathogenesis is not well defined. Although obesity, sedentary life-style, altered dietary pattern, insulin resistance, altered intestinal barrier function, inflammatory cytokines, and oxidative stress have been acknowledged as contributing factors because of the indefinite pathogenesis of metabolic diseases, the only reliable treatment is lifestyle intervention composed of restrictive diet and exercise. Additionally, some existing medications such as pioglitazone and antioxidants such as vitamin E were reported to be effective; in this review, several novel agents especifically targeting nonalcoholic fatty liver disease pathogenesis under clinical trial will be introduced. These include an NPC1L1 blocker (ezetimibe), which significantly improved histological and symptomatic scores associated with steatohepatitis and fibrosis; clofibrate, phentoxyfylline, ursodeoxycholic acid, and tocopherol, all of which are prescribed to relieve fat stress; and additional IgY targeted NPC1L1, tocotrienol, ursodeoxycholic acid, and ω-3 polyunsaturated fatty acids, which are actively under investigation to confirm the safety of long-term use.

Amelioration of non-alcoholic fatty liver disease with NPC1L1-targeted IgY or n-3 polyunsaturated fatty acids in mice.

Patients with non-alcoholic fatty liver disease (NAFLD) have an increased risk for progression to hepatocellular carcinoma in addition to comorbidities such as cardiovascular and serious metabolic diseases; however, the current therapeutic options are limited. Based on our previous report that omega-3 polyunsaturated fatty acids (n-3 PUFAs) can significantly ameliorate high fat diet (HFD)-induced NAFLD, we explored the therapeutic efficacy of n-3 PUFAs and N-IgY, which is a chicken egg yolk-derived IgY specific for the Niemann-Pick C1-Like 1 (NPC1L1) cholesterol transporter, on NAFLD in mice. We generated N-IgY and confirmed its efficient cholesterol transport-blocking activity in HepG2 and Caco-2 cells, which was comparable to the effect of ezetimibe (EZM). C57BL/6 wild type and fat-1 transgenic mice, capable of producing n-3 PUFAs, were fed a high fat diet (HFD) alone or supplemented with N-IgY. Endogenously synthesized n-3 PUFAs combined with N-IgY led to significant decreases in hepatic steatosis, fibrosis, and inflammation (p<0.01). The combination of N-IgY and n-3 PUFAs resulted in significant upregulation of genes involved in cholesterol uptake (LDLR), reverse cholesterol transport (ABCG5/ABCG8), and bile acid metabolism (CYP7A1). Moreover, fat-1 transgenic mice treated with N-IgY showed significant downregulation of genes involved in cholesterol-induced hepatic stellate cell activation (Tgfb1, Tlr4, Col1a1, Col1a2, and Timp2). Collectively, these data suggest that n-3 PUFAs and N-IgY, alone or in combination, represent a promising treatment strategy to prevent HFD-induced fatty liver through the activation cholesterol catabolism to bile acids and by decreasing cholesterol-induced fibrosis.

Hepatic Elovl6 gene expression is regulated by the synergistic action of ChREBP and SREBP-1c.

Elongation of very long chain fatty acids protein 6 (ELOVL6), a rate-limiting enzyme for the elongation of saturated and monounsaturated fatty acids with 12, 14, and 16 carbons, plays a key role in energy metabolism and insulin sensitivity. Hepatic Elovl6 expression is upregulated in the fasting-refeeding response and in leptin-deficient ob/ob mice. Mouse Elovl6 has been shown to be a direct target of sterol regulatory element binding protein-1 (SREBP-1) in response to insulin. In the present study, we demonstrated that mouse and human Elovl6 expression is under the direct transcriptional control of carbohydrate response element binding protein (ChREBP), a mediator of glucose-induced gene expression. Serial deletion and site-directed mutagenesis studies revealed functional carbohydrate response elements (ChoREs) in the mouse and human Elovl6 promoters and gel shift assays and chromatin immunoprecipitation assays confirmed the binding of ChREBP to the Elovl6-ChoRE sites. In addition, the ectopic co-expression of ChREBP and SREBP-1c in HepG2 cells synergistically stimulated Elovl6 promoter activity and this synergistic activation was abolished by mutating the Elovl6 promoter ChoREs. Taken together, these results suggest that the synergistic action of ChREBP and SREBP-1c is necessary for the maximal induction of Elovl6 expression in the liver.

Ursodeoxycholic acid decreases age-related adiposity and inflammation in mice.

Ursodeoxycholic acid (UDCA), a natural, hydrophilic nontoxic bile acid, is clinically effective for treating cholestatic and chronic liver diseases. We investigated the chronic effects of UDCA on age-related lipid homeostasis and underlying molecular mechanisms. Twenty-week-old C57BL/6 male and female mice were fed a diet with or without 0.3% UDCA supplementation for 25 weeks. UDCA significantly reduced weight gain, adiposity, hepatic triglyceride, and hepatic cholesterol without incidental hepatic injury. UDCA-mediated hepatic triglyceride reduction was associated with downregulated hepatic expression of peroxisome proliferator-activated receptor-γ, and of other genes involved in lipogenesis (Chrebp, Acaca, Fasn, Scd1, and Me1) and fatty acid uptake (Ldlr, Cd36). The inflammatory cytokines Tnfa, Ccl2, and Il6 were significantly decreased in liver and/or white adipose tissues of UDCA-fed mice. These data suggest that UDCA exerts beneficial effects on age-related metabolic disorders by lowering the hepatic lipid accumulation, while concurrently reducing hepatocyte and adipocyte susceptibility to inflammatory stimuli. [BMB Reports 2016; 49(2): 105-110].

Regulation of Cholesterol Metabolism in Liver: Link to NAFLD and Impact of n-3 PUFAs.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease that affects one-third of adults in westernized countries. NAFLD represents a wide spectrum of hepatic alterations, ranging from simple triglyceride accumulation in the liver to steatohepatitis. Several pharmaceutical approaches to NAFLD management have been examined, but no particular treatment has been considered both safe and highly effective. Growing evidence reveal that supplemental fish oil, seal oil and purified n-3 fatty acids can reduce hepatic lipid content in NAFLD through extensive regulation by inhibiting lipogenesis, promoting fatty acid oxidation and suppressing inflammatory responses. Recently, the fat-1 transgenic mice capable of converting n-6 to n-3 polyunsaturated fatty acids (PUFAs) have been used to examine the effects of endogenous n-3 PUFAs on NAFLD. The increased n-3 PUFAs in fat-1 transgenic mice reduced diet-induced hyperlipidemia and fatty liver through induction of CYP7A1 expression and activation of cholesterol catabolism to bile acid. This article introduces the n-3 PUFAs, and addresses the evidence and mechanisms by which endogenously synthesized n-3 PUFAs or increased dietary n-3 PUFAs may ameliorate NAFLD.

Endogenously synthesized n-3 polyunsaturated fatty acids in fat-1 mice ameliorate high-fat diet-induced non-alcoholic fatty liver disease.

Dietary n-3 polyunsaturated fatty acids (n-3 PUFAs) have well-documented protective effects against obesity-induced insulin resistance and hepatic steatosis. Here, we investigated the effects of endogenous n-3 PUFAs on diet-induced fatty liver disease using fat-1 transgenic mice (fat-1) capable of converting n-6 to n-3 PUFAs. Wild-type (WT) and fat-1 mice were maintained on a high-fat diet (HFD) for 5months. HFD-induced weight gain and fatty liver were more prominent in WT mice than fat-1 mice. Histological analysis indicated that WT mice fed the HFD developed moderate-to-severe macrovesicular steatosis, whereas fat-1 mice developed very mild steatosis. In addition, HFD-induced hepatocyte ballooning and fibrosis were ameliorated in fat-1 mice. Serum alanine transaminase (ALT) and aspartate transaminase (AST) levels were within the respective normal ranges in HFD-fed fat-1 mice, whereas both were significantly elevated in HFD-fed WT mice. The fat-1 mice showed significantly decreased serum lipid levels, including triglycerides, total cholesterol (TC), HDL-C, and LDL-C, compared to WT mice regardless of diet. Specifically, the increases in very low-density lipoprotein cholesterol (VLDL-C) and chylomicrons detected in HFD-fed WT mice were completely blunted in HFD-fed fat-1 mice. Gene expression analysis showed that hepatic Cyp7a1 mRNA and protein expression levels were markedly increased in HFD-fed fat-1 mice. In addition, genes involved in cholesterol uptake (Ldlr) and bile acid excretion (Abcg5 and Abcg8) were increased in the livers of fat-1 mice. These data suggest that n-3 PUFAs ameliorate diet-induced hyperlipidemia and fatty liver through induction of CYP7A1 expression and activation of cholesterol catabolism to bile acid.

Role of transcription factor modifications in the pathogenesis of insulin resistance.

Non-alcoholic fatty liver disease (NAFLD) is characterized by fat accumulation in the liver not due to alcohol abuse. NAFLD is accompanied by variety of symptoms related to metabolic syndrome. Although the metabolic link between NAFLD and insulin resistance is not fully understood, it is clear that NAFLD is one of the main cause of insulin resistance. NAFLD is shown to affect the functions of other organs, including pancreas, adipose tissue, muscle and inflammatory systems. Currently efforts are being made to understand molecular mechanism of interrelationship between NAFLD and insulin resistance at the transcriptional level with specific focus on post-translational modification (PTM) of transcription factors. PTM of transcription factors plays a key role in controlling numerous biological events, including cellular energy metabolism, cell-cycle progression, and organ development. Cell type- and tissue-specific reversible modifications include lysine acetylation, methylation, ubiquitination, and SUMOylation. Moreover, phosphorylation and O-GlcNAcylation on serine and threonine residues have been shown to affect protein stability, subcellular distribution, DNA-binding affinity, and transcriptional activity. PTMs of transcription factors involved in insulin-sensitive tissues confer specific adaptive mechanisms in response to internal or external stimuli. Our understanding of the interplay between these modifications and their effects on transcriptional regulation is growing. Here, we summarize the diverse roles of PTMs in insulin-sensitive tissues and their involvement in the pathogenesis of insulin resistance.

Peroxisome proliferator-activated receptor {alpha} is responsible for the up-regulation of hepatic glucose-6-phosphatase gene expression in fasting and db/db Mice.

Glucose-6-phosphatase (G6Pase) is a key enzyme that is responsible for the production of glucose in the liver during fasting or in type 2 diabetes mellitus (T2DM). During fasting or in T2DM, peroxisome proliferator-activated receptor α (PPARα) is activated, which may contribute to increased hepatic glucose output. However, the mechanism by which PPARα up-regulates hepatic G6Pase gene expression in these states is not well understood. We evaluated the mechanism by which PPARα up-regulates hepatic G6Pase gene expression in fasting and T2DM states. In PPARα-null mice, both hepatic G6Pase and phosphoenolpyruvate carboxykinase levels were not increased in the fasting state. Moreover, treatment of primary cultured hepatocytes with Wy14,643 or fenofibrate increased the G6Pase mRNA level. In addition, we have localized and characterized a PPAR-responsive element in the promoter region of the G6Pase gene. Chromatin immunoprecipitation (ChIP) assay revealed that PPARα binding to the putative PPAR-responsive element of the G6Pase promoter was increased in fasted wild-type mice and db/db mice. These results indicate that PPARα is responsible for glucose production through the up-regulation of hepatic G6Pase gene expression during fasting or T2DM animal models.

Role of resveratrol in FOXO1-mediated gluconeogenic gene expression in the liver.

During a state of fasting, the blood glucose level is maintained by hepatic gluconeogenesis. SIRT1 is an important metabolic regulator during nutrient deprivation and the liver-specific knockdown of SIRT1 resulted in decreased glucose production. We hypothesize that SIRT1 is responsible for the upregulation of insulin-suppressed gluconeogenic genes through the deacetylation of FOXO1. Treatment of primary cultured hepatocytes with resveratrol increased insulin-repressed PEPCK and G6Pase mRNA levels, which depend on SIRT1 activity. We found that the resveratrol treatment resulted in a decrease in the phosphorylation of Akt and FOXO1, which are independent of SIRT1 action. Fluorescence microscopy revealed that resveratrol caused the nuclear localization of FOXO1. In the nucleus, FOXO1 is deacetylated by SIRT1, which might make it more accessible to the IRE of the PEPCK and G6Pase promoter, causing an increase in their gene expression. Our results indicate that resveratrol upregulates the expression of gluconeogenic genes by attenuating insulin signaling and by deacetylating FOXO1, which are SIRT1-independent in the cytosol and SIRT1-dependent in the nucleus, respectively.

Transcriptional regulation of glucose sensors in pancreatic ß-cells and liver: an update.

Pancreatic ß-cells and the liver play a key role in glucose homeostasis. After a meal or in a state of hyperglycemia, glucose is transported into the ß-cells or hepatocytes where it is metabolized. In the ß-cells, glucose is metabolized to increase the ATP:ADP ratio, resulting in the secretion of insulin stored in the vesicle. In the hepatocytes, glucose is metabolized to CO(2), fatty acids or stored as glycogen. In these cells, solute carrier family 2 (SLC2A2) and glucokinase play a key role in sensing and uptaking glucose. Dysfunction of these proteins results in the hyperglycemia which is one of the characteristics of type 2 diabetes mellitus (T2DM). Thus, studies on the molecular mechanisms of their transcriptional regulations are important in understanding pathogenesis and combating T2DM. In this paper, we will review a recent update on the progress of gene regulation of glucose sensors in the liver and ß-cells.

Interrelationship between liver X receptor alpha, sterol regulatory element-binding protein-1c, peroxisome proliferator-activated receptor gamma, and small heterodimer partner in the transcriptional regulation of glucokinase gene expression in liver.

Liver glucokinase (LGK) plays an essential role in controlling blood glucose levels and maintaining cellular metabolic functions. Expression of LGK is induced mainly regulated by insulin through sterol regulatory element-binding protein-1c (SREBP-1c) as a mediator. Since LGK expression is known to be decreased in the liver of liver X receptor (LXR) knockout mice, we have investigated whether LGK might be directly activated by LXRalpha. Furthermore, we have studied interrelationship between transcription factors that control gene expression of LGK. In the current studies, we demonstrated that LXRalpha increased LGK expression in primary hepatocytes and that there is a functional LXR response element in the LGK gene promoter as shown by electrophoretic mobility shift and chromatin precipitation assay. In addition, our studies demonstrate that LXRalpha and insulin activation of the LGK gene promoter occurs through a multifaceted indirect mechanism. LXRalpha increases SREBP-1c expression and then insulin stimulates the processing of the membrane-bound precursor SREBP-1c protein, and it activates LGK expression through SREBP sites in its promoter. LXRalpha also activates the LGK promoter by increasing the transcriptional activity and induction of peroxisome proliferator-activated receptor (PPAR)-gamma, which also stimulates LGK expression through a peroxisome proliferator-responsive element. This activation is tempered through a negative mechanism, where a small heterodimer partner (SHP) decreases LGK gene expression by inhibiting the transcriptional activity of LXRalpha and PPARgamma by directly interacting with their common heterodimer partner RXRalpha. From these data, we propose a mechanism for LXRalpha in controlling the gene expression of LGK that involves activation through SREBP-1c and PPARgamma and inhibition through SHP.

Significant association of FcepsilonRIalpha promoter polymorphisms with aspirin-intolerant chronic urticaria.

BACKGROUND: Although the mechanism that underlies aspirin hypersensitivity is not completely understood, an IgE-mediated response was reported for a patient with aspirin-intolerant chronic urticaria (AICU). OBJECTIVE: We investigated whether genetic polymorphisms on the alpha-chain of the high-affinity IgE receptor (FcepsilonRIalpha) gene were associated with the AICU phenotype. METHODS: We genotyped 2 promoter polymorphisms (-344C>T and -95T>C) of FcepsilonRIalpha gene in the Korean population, and the functional effect of the -344C>T polymorphism was analyzed by using a luciferase reporter assay and an electrophoretic mobility shift assay. RESULTS: The rare allele frequency of the -344C>T polymorphism was significantly higher in the patients with AICU compared with the other subjects (P= .008 for AICU vs aspirin-tolerant chronic urticaria; P= .03 for AICU vs controls). This polymorphism was also significantly associated with total serum IgE concentrations and a higher rate of atopy in the patients with AICU (P= .01 and .05, respectively). The reporter plasmid that carried the -344T allele exhibited significantly higher promoter activity in a rat mast cell line (RBL-2H3) compared with the promoter activity of the -344C allele (P< .001). We found that transcription factor Myc-associated zinc finger protein preferentially bound the -344C promoter. Moreover, patients with AICU with the heterozygous CT genotype of the -344C>T polymorphism exhibited greater anti-IgE-mediated histamine release compared with those with the homozygous CC genotype. CONCLUSION: These results suggest that the -344C>T polymorphism of the FcepsilonRIalpha promoter may be associated with increased expression of FcepsilonRIalpha on mast cells and enhanced release of histamine. CLINICAL IMPLICATIONS: The FcepsilonRIalpha -344C>T polymorphism may contribute to the development of AICU.

Lack of an association between a newly identified promoter polymorphism (-1702G > A) of the leukotriene C4 synthase gene and aspirin-intolerant asthma in a Korean population.

Aspirin-intolerant asthma (AIA) is a distinct clinical syndrome that refers to the development of bronchoconstriction in asthmatic individuals following the ingestion of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). It is widely recognized that increased cysteinyl leukotriene (cysLT) biosynthesis is associated with the development and progression of AIA. Leukotriene C4 synthase (LTC4S) is the terminal enzyme in cysLT production and is a strong candidate gene in the pathogenesis of aspirin-intolerant asthma (AIA). In this paper, we report a new single nucleotide polymorphism (SNP) of the LTC4S promoter, -1702G>A, in AIA patients and evaluate its genetic role in the association with the LTC4S-444 A>C polymorphism. We enrolled 110 AIA patients, 125 aspirin-tolerant asthma (ATA) patients, and 125 normal controls. SNP genotyping of the LTC4S-1702G>A and -444A>C polymorphisms was performed using SNP-IT assays. Haplotype analyses were performed using Haploview version 2.05, which is based on an estimation-maximization (EM) algorithm. There were no significant differences in the allele or genotype frequencies of the LTC4S-1702G>A and -444A>C polymorphisms among the three groups (p > 0.05), with no significant differences in the observed haplotype frequencies (p > 0.05). Moreover, no significant associations were found between the genotype of each SNP in AIA patients with the clinical characteristics, including a forced expiratory volume in one second (FEV1) %, a provocation concentration of methacholine to induce more than 20% decrease of FEV1 (PC20) to methacholine, and serum total IgE levels (p > 0.05). These results indicate that there is no association between these two promoter polymorphisms of LTC4S and the phenotype of AIA in a Korean population.