Research Projects
Combining laboratory and field studies to identify the mechanisms of chemical toxicity at the cellular, tissue, organismal, and population levels utilizing comparative and translational study designs within the One Health framework.
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Research Area 1:
Novel Mechanisms and Exposure Windows of Reproductive Susceptibility to EDCs
Chemicals with the ability to disrupt hormone signaling, known as Endocrine Disrupting Chemicals (EDCs), are of particular concern for reproductive health given that the molecular events that drive reproductive functions rely on the endocrine system.
Project 1: Effects of Preconception Phthalate Exposure on Implantation and Placentation
Phthalates are known EDCs that have been shown to disrupt estrogen (E2) and progesterone (P4).
These EDCs are of particular concern for women’s reproductive health due to their prevalence in personal care, beauty, and feminine hygiene products.
While phthalate reproductive toxicity has been well established, we know very little about how these chemicals can impact the process of implantation and development of the placenta.
Using the CD-1 mouse as our in vivo model, we are currently investigating how exposure to phthalates between puberty and pregnancy (i.e., preconception) impacts implantation, placentation, and offspring health outcomes.
Project Lead: Maryam Afghah
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Building off of this main project we are also investigating maternal health outcomes associated with preconception exposure.
Many adaptations in maternal physiology occur during pregnancy in response to hormonal changes, putting strain on the maternal endocrine system.
Concurrent endocrine challenges, such as pregnancy and exposure to EDCs may have long-term adverse health outcomes for mom.
Using CD-1 mice and HepG2 cells we are investigating the impact of reproductive hormones and phthalates on maternal liver function and the liver-ovarian axis.
Project Lead: Ansley Elkins
Project 2: Probing the Direct Effects of Endocrine Disrupting Chemicals on Vaginal Cells
Exposure to some phthalates disproportionally burdens women of reproductive age and people of color due to their presence in personal care and feminine hygiene products.
The use of these items, particularly menstrual products, may lead to intravaginal exposure to phthalates.
However, almost nothing is known about intravaginal phthalate exposure or its impacts on vaginal health.
We are working to evaluate the effects of phthalate exposure on the function of female reproductive tract cells in vitro including vaginal epithelial cells (VK2), endocervical cells (End1), and ectocervical cells (Ect1).
Project Lead: Paige Powell
Collaborator: Hannah Zierden, Ph.D. (UM College Park)
Project 3: Unraveling the Impact of Fetal Sex on Expression and Activity of Xenobiotic Transporters at the Blood- Placenta Barrier
Project Leaders: Maryam Afghah & Sasha Suggs
Majority of people who are pregnant are exposed to complex mixtures of environmental contaminants and pharmaceuticals.
However, we lack sufficient information about maternal-fetal pharmacokinetics to truly understand the potential risk these xenobiotics (i.e., chemicals and drugs) pose to the developing fetus.
On major factor that dictates fetal exposure is the blood-placenta barrier (BPB).
Made up of cells that are fetal in origin, meaning they express fetal genetic sex (XX or XY), the BPB expresses a variety of xenobiotic transporters.
We are currently using in vivo and in situ approaches to understand whether and how placental transporter activity and abundance is altered by (1) fetal sex and (2) EDCs.
Collaborator: Amy Crockett, M.D., M.S.P.H (Prisma Health)
Funding
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Research Area 2:
Influence of Coastal Urbanization & Feeding Ecology on Bioaccumulation
Among the top three drivers of biodiversity loss in marine ecosystems is pollution, the pressure of which will continue to increase concurrently with global urbanization. This is a multifactorial issue that requires identifying key sources of pollution and factors that leave organisms vulnerable to exposure.
Project 1: Does Anthropogenic Contamination of Estuaries Impact Bioaccumulation in Seasonally Resident Versus Transient Elasmobranchs?
Many shark populations are in decline contributing to the precipitous loss of biodiversity that has been observed across the globe.
Elasmobranchs utilize coastal waters for feeding, breeding, pupping, and nursery grounds bringing them near our urbanized and polluted coastlines.
As marine predators, sharks are especially vulnerable to the negative impacts of chemical pollutants, which can accumulate to high concentrations in their tissues, threatening their health and survival.
Therefore, it is critical to understand how occupancy of coastal marine ecosystems contributes to contaminant exposure.
We are collecting environmental (air, water, sediment) and biological (elasmobranch blood, muscle) samples from San Francisco Bay, a heavily polluted urbanized estuary, and Willapa Bay, a comparatively pristine estuarine ecosystem to measure metals (e.g., mercury (Hg)) and persistent organic pollutants (e.g., Per- and polyfluoroalkyl substances (PFAS)).
Project Lead: Mel Walker
Collaborators: Meghan Holst, Ph.D. (UC Davis),
Taylor Chapple, Ph.D., & Jess Schulte (Oregon State)
Project 2: Evaluating Bioaccumulation and Biomagnification of Pollutants in Dietary Generalist Versus Specialist Elasmobranch Species
Coastal South Carolina is home to a variety of shark species, many of which are being routinely monitored as a part of population surveys being conducted by the South Carolina Department of Natural Resources (SCDNR).
Through these surveys, SCDNR scientists have identified local Finetooth (Carcharhinus isodon) sharks as specialist feeders, with >95% of their diet comprised of Atlantic menhaden (Brevoortia tyrannus).
In contrast, Sandbar (Carcharhinus plumbeus) sharks, which occupy the same habitats, are generalist feeders, consuming a large variety of fish and invertebrates.
Trophic level plays a role in body burden of pollutants but does not address their vulnerability based on differences in feeding ecology.
We are currently collecting samples to measure (1) Hg and PFAS in these two sharks and their prey and (2) perform stable isotope analysis.
Project Lead: Mel Walker
Collaborator: Bryan Frazier (SCDNR)
Research Area 3:
Interactions Between Marine Microbes and Pollutants
Organisms, including bacteria, that reside in estuaries, at the interface of marine, brackish, and freshwater habitats, are especially sensitive and adaptive to changes in environmental conditions and are expected to be useful in the early identification of habitat perturbations.
Project 1: Monitoring Seasonal Differences in Pollutants and Marine Microbial Communities in Estuaries
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Benthic fauna, which are mostly sedentary, can serve as reliable local indicators of environmental changes.
This includes benthic microfauna, such as bacteria, whose composition is dynamic and influenced by a host of environmental factors, including temperature, pH, salinity, and chemical pollutants.
Microbes play essential roles in estuaries, maintaining many biogeochemical processes such as nutrient cycling and even degradation of pollutants.
We are currently collecting sediment and water samples from estuaries in South Carolina to characterize seasonal changes in (1) microbial communities and (2) PFAS concentrations to better understand PFAS-microbial dynamics in estuaries
Project Lead: Zach Padgett
Collaborator: Andrew Tweel, Ph.D. (SCDNR)
Project 2: Bacterial Culture to Evaluate how PFAS and Climate Change-related Conditions Impact Microbial Dynamics & Functions
Using sediment collected for project 1, we plan to setup controlled culture experiments whereby we expose microbes to different PFAS concentrations and compounds and evaluate
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Changes in microbial composition and abundance, helping to identify microbes that are susceptible to PFAS toxicity and enrich for potential PFAS degraders
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Changes in PFAS concentration and composition, comparing pre and post exposure media concentrations of PFAS and their metabolites
