Single-nucleotide polymorphisms and haplotype of CYP2E1 gene associated with systemic lupus erythematosus in Chinese population

Hepatic, Extrahepatic and Extracellular Vesicle Cytochrome P450 2E1 in Alcohol and Acetaminophen-Mediated Adverse Interactions and Potential Treatment Options

Alcohol and several therapeutic drugs, including acetaminophen, are metabolized by cytochrome P450 2E1 (CYP2E1) into toxic compounds. At low levels, these compounds are not detrimental, but higher sustained levels of these compounds can lead to life-long problems such as cytotoxicity, organ damage, and cancer. Furthermore, CYP2E1 can facilitate or enhance the effects of alcohol-drug and drug-drug interactions. In this review, we discuss the role of CYP2E1 in the metabolism of alcohol and drugs (with emphasis on acetaminophen), mediating injury/toxicities, and drug-drug/alcohol-drug interactions. Next, we discuss various compounds and various nutraceuticals that can reduce or prevent alcohol/drug-induced toxicity. Additionally, we highlight experimental outcomes of alcohol/drug-induced toxicity and potential treatment strategies. Finally, we cover the role and implications of extracellular vesicles (EVs) containing CYP2E1 in hepatic and extrahepatic cells and provide perspectives on the clinical relevance of EVs containing CYP2E1 in intracellular and intercellular communications leading to drug-drug and alcohol-drug interactions. Furthermore, we provide our perspectives on CYP2E1 as a druggable target using nutraceuticals and the use of EVs for targeted drug delivery in extrahepatic and hepatic cells, especially to treat cellular toxicity.

Genetic variation of pharmacogenomic VIP variants in Zhuang nationality of southern China

Drug gene polymorphisms are strongly associated with disease. Previous studies have shown that the frequency of drug genes varies in different populations. At present, there are no reports about the polymorphism of the drug genome in the Zhuang population in southern China. This study conducted a pharmacogenomics study on the Zhuang population in southern China. Therefore, we conducted genotyping on 105 Zhuang samples, and compared the genotyping results with those of other 11 ethnic groups after statistical analysis. Our results show that, compared with the 11 populations in the HapMap data set, the differences between the CYP2E1 rs2070676 and CYP2D6 rs1065852 of the Zhuang nationality are the largest. This study fills in the blank of the drug genome information of the Zhuang nationality in southern China. The two sites of Rs2070676 (CYP2E1) and rs1065852 (CYP2D6) provide a reliable basis for the prediction of the efficacy of certain drugs. Its main purpose is to provide theoretical basis for safe drug use in the Zhuang region of southern China.

Acarbose Use and Liver Injury in Diabetic Patients With Severe Renal Insufficiency and Hepatic Diseases: A Propensity Score-Matched Cohort Study

Background: Acarbose has been deemed contraindicated in diabetic patients with chronic kidney disease (CKD) or end-stage renal disease (ESRD), but such use is not uncommon. We tested whether this concept hold true in this population with different background hepatic diseases.

Methods: All incident diabetic patients (n = 2,036,531) with stage 5 CKD/ESRD were enrolled from Taiwan between 2017 and 2013 and divided into those without chronic liver disease (CLD), with CLD but without cirrhosis, and those with cirrhosis. Among each group, acarbose users, defined as cumulative use >30 days within the preceding year, were propensity-score matched 1:2 to non-users. Our main outcome was the development of liver injury events during follow-up.

Results: Acarbose users did not exhibit an increased incidence of liver injury during follow-up compared to non-users (hazard ratio and 95% confidence interval, 1.04 [0.88–1.25], 0.97 [0.61–1.56], and 0.71 [0.33–1.54] among those without CLD, with CLD but without cirrhosis, and those with cirrhosis, respectively), after adjusting for demographic profiles, comorbidities, potentially hepatotoxic medication use, and diabetic severity.

Conclusions: The incidence of liver injury did not increase significantly among diabetic acarbose users with severe renal insufficiency than non-users, regardless of the presence or absence of chronic liver disease. Our findings support the renaissance of acarbose as a useful adjunct in diabetic patients with stage 5 and 5D chronic kidney disease.

Epigenetics and MicroRNAs in Pharmacogenetics

Germline pharmacogenetics has so far mainly studied common variants in "pharmacogenes," i.e., genes encoding drug metabolizing enzymes and transporters (DMET genes), certain auxiliary and regulatory genes, and drug target genes. Despite remarkable progress in understanding genetically determined differences in pharmacokinetics and pharmacodynamics of drugs, currently known common variants even in important pharmacogenes explain genetic variability only partially. This suggests "missing heritability" that may in part be due to rare variants in the classical pharmacogenes, but current evidence suggests that largely unexplored resources with potential for pharmacogenetics exist, both within already known pharmacogenes and in entirely new areas. In particular, recent studies suggest that epigenetic processes and noncoding RNAs, including mostly microRNAs (miRNAs), represent important and largely unexplored layers of DMET gene regulation that may fill some of the gaps in understanding interindividual variability and lead to new biomarkers. In this chapter we summarize recent advances in the understanding of genetic variability in epigenetic and miRNA-mediated processes with focus on their significance for DMET regulation and pharmacokinetic or pharmacological endpoints.

CYP2E1 Gene Polymorphisms Related to the Formation of Coronary Artery Lesions in Kawasaki Disease

BACKGROUND

Kawasaki disease (KD) is an acute febrile systemic vasculitis that disturbs coronary arteries. Patients' risks of adverse cardiovascular events and subclinical atherosclerosis have been found to significantly increase with polymorphisms of the human cytochrome P450. This current study aims to research the possible relationship between cytochrome P450, family 2, subfamily E and polypeptide 1 (CYP2E1) polymorphisms with KD.

METHODS

We selected 6 tag single-nucleotide polymorphisms (SNPs) of the CYP2E1 gene for TaqMan allelic discrimination assay in 340 KD patients and performed analysis on the clinical phenotypes and coronary artery lesions (CALs). CAL associations of tag SNPs were adjusted for age and gender in the logistic regression.

RESULTS

The KD patients with a CC genotype of rs915906 demonstrated a greater proportion of CAL formation (P = 0.009). Furthermore, the GG genotype frequencies of rs2070676 showed a significantly greater risk for CAL formation in KD patients (P = 0.007). However, the SNPs of the CYP2E1 gene did not influence CAL formation in the participating KD patients either with or without high-dose acetylsalicylic acid. Using the expression quantitative trait locus analyses, we found that the SNPs associated with CAL formation in KD also affected CYP2E1 expression in certain cell types.

CONCLUSION

This study is the first to find that the risk of CAL formation is related to CYP2E1 gene polymorphisms in KD patients.

Genetic polymorphism analysis of cytochrome P4502E1 (CYP2E1) in a Chinese Tibetan population

Cytochrome P4502E1 (CYP2E1) gene genetic polymorphisms vary markedly in frequency among different ethnic and racial groups.We studied the genotype distributions and allele frequencies of 3 CYP2E1 polymorphisms: CYP2E11A, CYP2E17A, and CYP2E17C by polymerase chain reaction technique in a sample of 100 healthy subjects representing Tibetan population.The frequencies of CYP2E11A, 7A, and 7C alleles were 0.705, 0.125, and 0.170, respectively. Compared with other populations, we found that the allele frequencies of the variants -352A>G (rs2070672) and -333A>T (rs2070673) in this Tibetan population have significant differences compared with European-American, African-American, Japanese, Korean, and other different geographic areas in Chinese Han population. Furthermore, the results of protein prediction revealed that the variant 6397G>A (rs61710826) could influence the protein structure and function.These findings in this study would be valuable for pharmacogenetics for drug therapy and drug discovery. However, further studies in larger samples are warranted to confirm our results.

Single-Nucleotide Polymorphisms in Cytochrome P450 2E1 (CYP2E1) 3'-Untranslated Region Affect the Regulation of CYP2E1 by miR-570

Human cytochrome P450 2E1 (CYP2E1) catalyzes the metabolism of numerous xenobiotics, including acetaminophen and ethanol. CYP2E1 expression is known to be extensively regulated by post-transcriptional and post-translational mechanisms. A previous study had reported that a single-nucleotide polymorphism (SNP) 1561A>G in the 3'-untranslated region (3'-UTR) of CYP2E1 leads to a decreased CYP2E1 mRNA level in human peripheral blood mononuclear cells. In this study, we examined the possibility that microRNA(s) (miR) may be involved in the SNP-mediated modulation of CYP2E1 expression. Genotyping and sequencing analyses revealed that another SNP, 1556T>A, in the 3'-UTR was in complete linkage disequilibrium with the SNP 1561A>G. We termed the alleles with 1556T and 1561A or 1556A and 1561G haplotype I or II, respectively. A luciferase assay revealed that miR-570 recognizes the CYP2E1 3'-UTR of haplotype I but not haplotype II. Human embryonic kidney 293 (HEK293) cell lines stably expressing human CYP2E1 that included the 3'-UTR of haplotype I or II (HEK/2E1(I) or HEK/2E1(II) cells, respectively) were established. Overexpression of miR-570 significantly decreased the CYP2E1 protein level in the HEK/2E1(I) cells but not in the HEK/2E1(II) cells. In seven human livers with diplotype I/I, the CYP2E1 protein levels were inversely correlated with the miR-570 levels, but no relationship was observed in 25 human livers with diplotypes I/II and II/II. Collectively, it was demonstrated that human CYP2E1 was regulated by miR-570 in a genotype-dependent manner. This report describes the first proof that SNP in 3'-UTR of human P450 affects binding of miRNA to modulate the expression in the liver.

Impact of the Interaction between 3'-UTR SNPs and microRNA on the Expression of Human Xenobiotic Metabolism Enzyme and Transporter Genes

Genetic variation in the expression of human xenobiotic metabolism enzymes and transporters (XMETs) leads to inter-individual variability in metabolism of therapeutic agents as well as differed susceptibility to various diseases. Recent expression quantitative traits loci (eQTL) mapping in a few human cells/tissues have identified a number of single nucleotide polymorphisms (SNPs) significantly associated with mRNA expression of many XMET genes. These eQTLs are therefore important candidate markers for pharmacogenetic studies. However, questions remain about whether these SNPs are causative and in what mechanism these SNPs may function. Given the important role of microRNAs (miRs) in gene transcription regulation, we hypothesize that those eQTLs or their proxies in strong linkage disequilibrium (LD) altering miR targeting are likely causative SNPs affecting gene expression. The aim of this study is to identify eQTLs potentially regulating major XMETs via interference with miR targeting. To this end, we performed a genome-wide screening for eQTLs for 409 genes encoding major drug metabolism enzymes, transporters and transcription factors, in publically available eQTL datasets generated from the HapMap lymphoblastoid cell lines and human liver and brain tissue. As a result, 308 eQTLs significantly (p < 10⁻⁵) associated with mRNA expression of 101 genes were identified. We further identified 7,869 SNPs in strong LD (r² ≥ 0.8) with these eQTLs using the 1,000 Genome SNP data. Among these 8,177 SNPs, 27 are located in the 3′-UTR of 14 genes. Using two algorithms predicting miR-SNP interaction, we found that almost all these SNPs (26 out of 27) were predicted to create, abolish, or change the target site for miRs in both algorithms. Many of these miRs were also expressed in the same tissue that the eQTL were identified. Our study provides a strong rationale for continued investigation for the functions of these eQTLs in pharmacogenetic settings.