Environmental Concentrations of the Type 2 Diabetes Medication Metformin and Its Transformation Product Guanylurea in Surface Water and Sediment in Ontario and Quebec, Canada.

Metformin, used to treat Type 2 diabetes, is the active ingredient of one of the most prescribed drugs in the world, with over 120 million yearly prescriptions globally. In wastewater-treatment plants (WWTPs), metformin can undergo microbial transformation to form the product guanylurea, which could have toxicological relevance in the environment. Surface water samples from 2018 to 2020 and sediment samples from 2020 were collected from six mixed-use watersheds in Quebec and Ontario, Canada, and analyzed to determine the metformin and guanylurea concentrations at each site.

Long and Short Duration Exposures to the Selective Serotonin Reuptake Inhibitors (SSRIs) Fluoxetine, Paroxetine and Sertraline at Environmentally Relevant Concentrations Lead to Adverse Effects on Zebrafish Behaviour and Reproduction.

Selective serotonin reuptake inhibitors (SSRIs) are currently the most prescribed class of psychotropic medications. Their increased global manufacture and use have become growing concerns for aquatic toxicologists and environmental biologists, who assess both the direct and indirect effects of substances on the environment and on human health. In order to assess the potential impact of environmentally relevant levels of SSRIs on fish development, behaviour and reproduction, we exposed juvenile and adult zebrafish to a select group of SSRIs using two separate exposure paradigms.

P-Glycoprotein (P-gp)/ABCB1 plays a functional role in extravillous trophoblast (EVT) invasion and is decreased in the pre-eclamptic placenta.

Dysregulation of trophoblast differentiation is implicated in the placental pathologies of intrauterine growth restriction and pre-eclampsia. P-glycoprotein (P-gp encoded by ABCB1) is an ATP-binding cassette transporter present in the syncytiotrophoblast layer of the placenta where it acts as a molecular sieve. In this study, we show that P-gp is also expressed in the proliferating cytotrophoblast (CT), the syncytiotrophoblast (ST) and the extravillous trophoblast (EVT), suggesting our hypothesis of a functional role for P-gp in placental development.

Lymphoblastoid cell lines reveal associations of adult DNA methylation with childhood and current adversity that are distinct from whole blood associations.

Background: Some cohort studies bank lymphoblastoid cell lines (LCLs) as a renewable source of participant DNA. However, although LCL DNA has proved valuable for genetic studies, its utility in epigenetic epidemiology research is unknown.

Methods: To assess whether LCL DNA can be used for life-course environmental epigenomics, we carried out a pilot methylomic study (using the Illumina Infinium Human Methylation 450 BeadChip) of nil-passage, Epstein-Barr virus (EBV)-transformed LCLs (n = 42) and 28 matched whole-blood (WB) samples.

The multidrug resistance 1 gene Abcb1 in brain and placenta: comparative analysis in human and guinea pig.

The Multidrug Resistance 1 (MDR1; alternatively ABCB1) gene product P-glycoprotein (P-gp), an ATP binding cassette transporter, extrudes multiple endogenous and exogenous substrates from the cell, playing an important role in normal physiology and xenobiotic distribution and bioavailability. To date, the predominant animal models used to investigate the role of P-gp have been the mouse and rat, which have two distinct genes, Abcb1a and Abcb1b. In contrast, the human has a single gene, ABCB1, for which only a single isoform has been validated.

Human leukocyte telomere length is associated with DNA methylation levels in multiple subtelomeric and imprinted loci.

In humans, leukocyte telomere length (LTL) is positively correlated with lifespan, and shorter LTL is associated with increased risk of age-related disease. In this study we tested for association between telomere length and methylated cytosine levels. Measurements of mean telomere length and DNA methylation at >450,000 CpG sites were obtained for both blood (N = 24) and EBV-transformed cell-line (N = 36) DNA samples from men aged 44-45 years.

Childhood abuse is associated with methylation of multiple loci in adult DNA.

Background: Childhood abuse is associated with increased adult disease risk, suggesting that processes acting over the long-term, such as epigenetic regulation of gene activity, may be involved. DNA methylation is a critical mechanism in epigenetic regulation. We aimed to establish whether childhood abuse was associated with adult DNA methylation profiles.

Knockdown of RARB2 identifies a dual role in cancer.

Two chemoprevention trials have shown that retinoic acid (RA) may be harmful in patients at risk for lung cancer, and RA administration to this high-risk group results in RARB2 reactivation. Although RARB2 is thought to possess tumor suppressive activity, its expression has recently been correlated with poorer prognosis in patients with nonsmall cell lung cancer. We hypothesized that RARB2 expression is necessary for the growth and maintenance of the oncogenic phenotype in lung cancer cells in which RARB2 has not been inactivated.

A modified protocol for bisulfite genomic sequencing of difficult samples.

The bisulfite genomic sequencing protocol is a widely used method for analyzing DNA methylation. It relies on the deamination of unmethylated cytosine residues to uracil; however, its high rates of DNA degradation and incomplete cytosine to uracil conversion often lead to failed experiments, uninformative results, and false positives. Here, we report the addition of a single-step multiple restriction enzyme digestion (MRED) designed to differentially digest polymerase chain reaction products amplified from unconverted DNA while leaving those of converted DNA intact.

Allelic methylation bias of the RARB2 tumor suppressor gene promoter in cancer.

Retinoic acid receptor B2 (RARB2) is frequently inactivated in cancer. Methylation in the 5'-untranslated region and first exon is known to play a role; however, few studies have analyzed the detailed methylation pattern of the promoter region. We show that hypo- and hypermethylated alleles coexist in 5/11 cell lines in which RARB2 is inactivated.