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Your Environment. Your Health.

Superfund Research Program (SRP) Trainee Webinar Series: Session 3

August 1, 2012 - 1-2 pm Eastern Time

The NIEHS Superfund Research Program (SRP) is excited to announce the next session of our SRP Trainee Webinar Series! This is a series of webinars throughout the year highlighting the outstanding research/activities conducted by our trainees (graduate students and post-docs). The 3rd Session will be on August 1, 2012 at 1:00 p.m. Eastern Time and will include talks from Lauren Tetz (University of Michigan/Northeastern University) and Fabian Grimm (University of Iowa). Both trainees were poster award winners at the SRP Annual Meeting in Lexington, KY, in October, 2011. This will be an excellent opportunity for you to learn about their award winning research!

To see who has presented at our previous webinar series, please see the following webpage: 2012 Trainee Webinar Series

To register for the webinar, please see the Webinar Registration page, and for more information, please see the announcement below.
A live viewing will also take place in Keystone 2128.

Superfund Research Program Trainee Webinar Series

This webinar series features the outstanding work of graduate students and postdoctoral fellows conducting SRP-funded research. Specifically, this year’s series consists of presentations from Poster Award Winners from the previous SRP Annual Meeting. This is an excellent opportunity for peers, SRP researchers, alumni, and partners to hear the poster winners describe their current research/activities. It also provides an opportunity for others to learn more about the research/activities being conducted by SRP trainees. Most importantly, the intent of this series is to increase collaboration and an exchange of ideas among young, SRP-funded investigators.

Session III Presenters and Abstracts:

Lauren Tetz

Lauren Tetz
University of Michigan – Northeastern University Superfund Research Program Center
Presentation Title: Mono-2-Ethylhexyl Phthalate-Induced Oxidative Stress in Human Placental Cells

Abstract: Exposure to di-2-ethylhexyl phthalate (DEHP), an environmental contaminant used as a plasticizer, increases risk of adverse pregnancy outcomes in humans. Moreover, monoethylhexyl phthalate (MEHP), the active metabolite of DEHP, increases oxidative stress responses in vitro, which is linked to the pathogenesis of preterm birth. The researchers investigated MEHP stimulated oxidative stress in human placental cells as a mechanism by which MEHP exposure may contribute to preterm birth. They treated human placental cells with MEHP and measured reactive oxygen species (ROS) generation. They found that MEHP increased ROS generation, oxidative DNA damage, and apoptosis, and modified redox-sensitive gene expression. Notably, MEHP significantly induced mRNA expression of prostaglandin-endoperoxide synthase 2 (PTGS2), the gene for COX-2, an enzyme important for prostaglandin synthesis and labor initiation. These findings warrant future epidemiological studies of oxidative stress as a mechanism by which MEHP may contribute to preterm birth and other adverse pregnancy outcomes.

Fabian Grimm

Fabian Grimm
University of Iowa Superfund Research Program
Presentation Title: Sulfated Metabolites of Polychlorinated Biphenyls are High-Affinity Ligands for Human Transthyretin

Abstract: Exposure to polychlorinated biphenyls (PCBs), environmentally persistent hazardous chemicals, is related to pathological abnormalities of the thyroid gland and decreased serum levels of thyroid hormones. Certain hydroxylated metabolites of PCBs (OHPCBs) are capable of displacing L-thyroxine from transthyretin (TTR). Some OHPCBs are excellent substrates for cytosolic sulfotransferases that catalyze the formation of sulfate conjugates, but little is known about the fate or toxicities of these sulfate esters. PCB sulfates structurally resemble thyroxine and may represent a second class of high affinity ligands for thyroxine binding sites on TTR. To test this, the sulfate esters of five mono‐hydroxylated PCB congeners and their respective OHPCBs were examined for their ability to bind to human TTR. All five PCB sulfates were able to bind to the high-affinity binding site with Kd values similar to those determined for their respective OHPCB precursors and for L-thyroxine. In addition, the binding interactions of PCB sulfates to TTR were found to be non-covalent and fully reversible. Molecular docking simulations were utilized to calculate the lowest energy binding conformations of these PCB sulfates within the thyroxine binding site of human TTR, thereby providing corroborating evidence for their binding potential. Moreover, the corresponding OHPCBs were found to be substrates for human and rat forms of sulfotransferase 1A1. These results on the binding of PCB‐sulfates to TTR suggest a potential relevance in PCB‐mediated thyroid disruption.

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