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Background: Many genetic mutations affect aortic structure and function in mice, but little is known about the influence of background strain. We compared the biomechanical, structural, and gene expression responses of C57BL/6J and 129SvEv aortas to angiotensin II (AngII)-induced hypertension. Methods: After AngII infusion (14-day, 1000 ng/kg/min) and euthanasia, excised thoracic aortas were characterized functionally using isobaric vasoactive and cyclic passive stiffness tests. Immunohistochemistry quantified medial/adventitial composition and infiltration of pan-inflammatory CD45+ cells. RNA sequencing-based gene ontology, wall stress analyses, and growth and remodeling (G&R) simulations were performed to complement our mechanical findings. Results: Baseline aortic geometry, composition, and biomechanical properties, as well as AngII-induced blood pressure increases (+34% vs. +32%, systolic), were similar across strains. Yet, AngII-induced aortic remodeling differed dramatically, with gross maladaptive, fibrotic remodeling (exuberant medial/adventitial thickening) in C57BL/6J but not in 129SvEv mice (+89% vs. +12% thickness increase, p = 0.022). CD45+ cell density was markedly higher in hypertensive C57BL/6J than 129SvEv aortas (p = 0.001), while vasoconstrictive responses to AngII (causing a wall stress decrease Δσ) were greater in 129SvEv than C57BL/6J mice, both before (Δσ = −8 vs. −24%, p = 0.023) and after (Δσ = -24 vs. −46%, p < 0.001) hypertension. Gene expression, stress analyses, and G&R simulations reinforced the emergent hypothesis that mechanical stress-mediated immune processes promote maladaptive remodeling while smooth muscle contractile processes reduce wall stress and thereby protect against fibrosis (Figure). Conclusions: Differentially expressed mechano-sensitive genes play key roles in the distinct hypertensive aortic remodeling in C57BL/6J and 129SvEv mice and must be considered when comparing studies in different background strains. [ABSTRACT FROM AUTHOR]

Ovarian clear cell carcinomas (OCCCs) account for about 5-13% of all epithelial ovarian carcinomas in Western populations. It is characterised by resistance to conventional platinum-based chemotherapy, and new therapeutic strategies are urgently required. This article will focus on how recent discoveries have enhanced our understanding of the molecular pathogenesis of OCCCs, leading to new therapeutic opportunities. These include mutations in ARID1A, which provides a link to endometriosis, upregulation of the phosphatidylinositol 3-kinase/AKT pathway, particularly through mutations of PIK3CA and inactivation of PTEN, and increased activity of pathways involved in angiogenesis. Targeting HER2, apoptotic escape mechanisms and mismatch repair defects offer additional opportunities for treating this enigmatic tumour subtype. [ABSTRACT FROM AUTHOR]

Mutants with a defective non-homologous-end-joining (NHEJ) pathway have boosted functional genomics in filamentous fungi as they are very efficient recipient strains for gene-targeting approaches, achieving homologous recombination frequencies up to 100%. For example, deletion of the ku70 homologous gene kusA in Aspergillus niger resulted in a recipient strain in which deletions of essential or non-essential genes can efficiently be obtained. To verify that the mutant phenotype observed is the result of a gene deletion, a complementation approach has to be performed. Here, an intact copy of the gene is transformed back to the mutant, where it should integrate ectopically into the genome. However, ectopic complementation is difficult in NHEJ-deficient strains, and the gene will preferably integrate via homologous recombination at its endogenous locus. To circumvent that problem, we have constructed autonomously replicating vectors useful for many filamentous fungi which contain either the pyrG allele or a hygromycin resistance gene as selectable markers. Under selective conditions, the plasmids are maintained, allowing complementation analyses; once the selective pressure is removed, the plasmid becomes lost and the mutant phenotype prevails. Another disadvantage of NHEJ-defective strains is their increased sensitivity towards DNA damaging conditions such as radiation. Thus, mutant analyses in these genetic backgrounds are limited and can even be obscured by pleiotropic effects. The use of sexual crossings for the restoration of the NHEJ pathway is, however, impossible in imperfect filamentous fungi such as A. niger. We have therefore established a transiently disrupted kusA strain as recipient strain for gene-targeting approaches. [ABSTRACT FROM AUTHOR]

Increased activity of CYP2E1 has been associated with increased risk of chemically-mediated cancers, through enhanced activation of a variety of procarcinogens. In this context, inhibition of CYP2E1 is potentially of significance in xenobiotic toxicity. The aim of the present study was to test the hypothesis that quinacrine inhibits hepatic CYP2E1. For this purpose, disulfiram (75 mg/kg i.p) as an inhibitor and isoniazid (100 mg/kg i.p) as an inducer of CYP2E1, as well as quinacrine (50 mg/kg i.p) were administered to Wistar rats and the hepatic activity of CYP2E1 was measured. The expression of CYP2E1 was further assessed by Western blot analysis. As expected, disulfiram inhibited, while isoniazid induced the activity and expression of the enzyme. Interestingly, treatment with quinacrine resulted in a significant decrease of CYP2E1 activity and expression. To investigate any similarities in the inhibition of CYP2E1 by quinacrine and disulfiram, molecular modeling techniques were adopted and revealed that quinacrine molecule anchors inside the same binding pocket of the protein where disulfiram is also attached. Finally, as assessed by the sister chromatid exchanges (SCE) assay, quinacrine was demonstrated to reduce the mutagenic effects of the tobacco-specific N-nitrosamine 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), which is known to be converted to active mutagen in the liver principally through CYP2E1. We suggest that these antimutagenic effects of quinacrine could be possibly attributed, at least in part, to its ability to block the bioactivation of NNK, mainly by the inhibition of CYP2E1. Our results, even preliminary, indicate that quinacrine as an inhibitor of CYP2E1 might be protective against chemically-induced toxicities such as NNK-induced mutagenicity. [ABSTRACT FROM AUTHOR]