Associations of rs4244285 in the CYP2C19 gene with multifactorial diseases

Xenobiotic metabolism system in the current populations is involved in the biotransformation of a wide range of endogenous substrates and various xenobiotics, which can contribute to developing the diseases of various organ systems, and, in some cases, comorbid conditions where increased biotransformation system activity is observed. In this regard, it is of great interest to study the involvement of polymorphism in xenobiotic metabolism genes in the development of both isolated pathology and various comorbid conditions.Aim. The goal of study was to investigate the involvement of rs4244285 in the CYP2C19 gene in the development of isolated pathology and comorbidities.Material and Methods. The frequencies of alleles and genotypes were studied in groups of patients with comorbid conditions including groups of coronary artery disease (CAD) with hypertension (HTN) (CAD_HTN, n = 133) and bronchial asthma (BA) with HTN (BA_HTN, n = 178), in group of isolated BA (n = 135), and in the population sample of the city of Tomsk (n = 377). Association analysis covered three initial groups of patients (CAD, BA, and BA_HTN) and subgroups assigned based on the presence of absence of HTN diagnosis taking into account comorbid conditions both in patient samples and in population control.Results and Discussion. The study demonstrated the predisposing eff ect of GA genotype on the development of comorbid BA and HTN (OR = 1.94, p = 0.038) and comorbid CAD and HTN (OR = 2.26, p = 0.009) compared to isolated BA. The AA genotype was observed 3.98 times less often in HTN patients than in normotensive individuals. However, the diff erences did not reach the level of statistical signifi cance due to the low occurrence of this genotype.Conclusion. The obtained results may be explained by the involvement of CYP2C19-metabolites of arachidonic acid in the regulation of vascular tone, which requires further study.

The Epidermis: Redox Governor of Health and Diseases

A functional epithelial barrier necessitates protection against dehydration, and ichthyoses are caused by defects in maintaining the permeability barrier in the stratum corneum (SC), the uppermost protective layer composed of dead cells and secretory materials from the living layer stratum granulosum (SG). We have found that loricrin (LOR) is an essential effector of cornification that occurs in the uppermost layer of SG (SG1). LOR promotes the maturation of corneocytes and extracellular adhesion structure through organizing disulfide cross-linkages, albeit being dispensable for the SC permeability barrier. This review takes psoriasis and AD as the prototype of impaired cornification. Despite exhibiting immunological traits that oppose each other, both conditions share the epidermal differentiation complex as a susceptible locus. We also review recent mechanistic insights on skin diseases, focusing on the Kelch-like erythroid cell-derived protein with the cap “n” collar homology-associated protein 1/NFE2-related factor 2 signaling pathway, as they coordinate the epidermis-intrinsic xenobiotic metabolism. Finally, we refine the theoretical framework of thiol-mediated crosstalk between keratinocytes and leukocytes in the epidermis that was put forward earlier.

4-O-Glucosylation of Trichothecenes by Fusarium Species: A Phase II Xenobiotic Metabolism for t-Type Trichothecene Producers

The t-type trichothecene producers Fusarium sporotrichioides and Fusarium graminearum protect themselves against their own mycotoxins by acetylating the C-3 hydroxy group with Tri101p acetylase. To understand the mechanism by which they deal with exogenously added d-type trichothecenes, the Δtri5 mutants expressing all but the first trichothecene pathway enzymes were fed with trichodermol (TDmol), trichothecolone (TCC), 8-deoxytrichothecin, and trichothecin. LC-MS/MS and NMR analyses showed that these C-3 unoxygenated trichothecenes were conjugated with glucose at C-4 by α-glucosidic linkage. As t-type trichothecenes are readily incorporated into the biosynthetic pathway following the C-3 acetylation, the mycotoxins were fed to the ΔFgtri5ΔFgtri101 mutant to examine their fate. LC-MS/MS and NMR analyses demonstrated that the mutant conjugated glucose at C-4 of HT-2 toxin (HT-2) by α-glucosidic linkage, while the ΔFgtri5 mutant metabolized HT-2 to 3-acetyl HT-2 toxin and T-2 toxin. The 4-O-glucosylation of exogenously added t-type trichothecenes appears to be a general response of the ΔFgtri5ΔFgtri101 mutant, as nivalenol and its acetylated derivatives appeared to be conjugated with hexose to some extent. The toxicities of 4-O-glucosides of TDmol, TCC, and HT-2 were much weaker than their corresponding aglycons, suggesting that 4-O-glucosylation serves as a phase II xenobiotic metabolism for t-type trichothecene producers.

Direct Transcriptomic Comparison of Xenobiotic Metabolism and Toxicity Pathway Induction of Airway Epithelium Models at an Air Liquid Interface Generated from Induced Pluripotent Stem Cells and Primary Bronchial Epithelial Cells

The airway epithelium represents the main barrier between inhaled air and the tissues of the respiratory tract and is therefore an important point of contact with xenobiotic substances into the human body. Several studies have recently shown that in vitro models of the airway grown at an air liquid interface (ALI) can be particularly useful to obtain mechanistic information about the toxicity of chemical compounds. However, such methods are not very amenable to high throughput since the primary cells cannot be expanded indefinitely in culture to obtain a sustainable number of cells. Induced pluripotent stem cells (iPSCs) have become a popular option in the recent years for modelling the airways of the lung, but despite progress in the field, such models have so far not been assessed for their ability to metabolise xenobiotic compounds and how they compare to the primary bronchial airway model (pBAE). Here we report a comparative analysis by TempoSeq (oligo directed sequencing) of an iPSC derived airway model (iBAE) with a primary bronchial airway model (pBAE). The iBAE and pBAE were differentiated at an ALI and then evaluated in a 5-compound screen with exposure to a sub lethal concentration of each compound for 24 hours. We found that despite lower expression of xenobiotic metabolism genes, that the iBAE similarly predicted the toxic pathways when compared to the pBAE model. Our results show that iPSC airway models at ALI show promise for inhalation toxicity assessments with further development.

Development, scrutiny, and modulation of transient reporter gene assays of the xenobiotic metabolism pathway in zebrafish hepatocytes

The “toxicology in the twenty-first century” paradigm shift demands the development of alternative in vitro test systems. Especially in the field of ecotoxicology, coverage of aquatic species-specific assays is relatively scarce. Transient reporter gene assays could be a quick, economical, and reliable bridging technology. However, the user should be aware of potential pitfalls that are influenced by reporter vector geometry. Here, we report the development of an AhR-responsive transient reporter-gene assay in the permanent zebrafish hepatocytes cell line (ZFL). Additionally, we disclose how viral, constitutive promoters within reporter-gene assay cassettes induce squelching of the primary signal. To counter this, we designed a novel normalization vector, bearing an endogenous zebrafish-derived genomic promoter (zfEF1aPro), which rescues the squelching-delimited system, thus, giving new insights into the modulation of transient reporter systems under xenobiotic stress. Finally, we uncovered how the ubiquitously used ligand BNF promiscuously activates multiple toxicity pathways of the xenobiotic metabolism and cellular stress response in an orchestral manner, presumably leading to a concentration-related inhibition of the AhR/ARNT/XRE-toxicity pathway and non-monotonous concentration–response curves. We named such a multi-level inhibitory mechanism that might mask effects as “maisonette squelching.” Graphical abstract A transient reporter gene assay in zebrafish cell lines utilizing endogenous regulatory gene elements shows increased in vitro toxicity testing performance. Synthetic and constitutive promotors interfere with signal transduction (“squelching”) and might increase cellular stress (cytotoxicity). The squelching phenomenon might occur on multiple levels (toxicity pathway crosstalk and normalization vector), leading to a complete silencing of the reporter signal.