My name is Rosanna Jiang, and I am a rising junior studying Environmental Science and Chemistry at the University of Pennsylvania. At Penn, I am heavily involved in the performing arts community on two dance groups and entrepreneurial competitions. I am passionate about environmental conservation and addressing health inequities due to environmental exposures. This summer, I had the wonderful honor and opportunity to intern in Dr. Aalim Weljie and Dr. Rebecca Simmons’ labs, studying the metabolic and reproductive health effects of exposure to perfluorooctanoic acid (PFOA).
What is your summer research project?
PFOA is widespread, highly resistant to degradation, and accumulates in humans due to constant exposure. In preliminary research of the effects of PFOA, it is known that PFOA targets certain organs, including the liver, kidney, and placenta. As a result, it can be harmful to metabolic and reproductive health. Our hypothesis for this summer is to study PFOA under the lens of a possible endocrine-disrupting chemical (EDC) that can alter the biological circadian clock and increase the risk of developing diabetes, obesity, and non-alcoholic fatty liver disease.
Collaborating with Nikita Bharati, I worked with two experimental models to explore the effects of PFOA exposure at varying dosages. In Dr. Weljie’s lab under the guidance of Dr. Lisa Bottalico, we have conducting qPCR and circadian clock recording experiments on mouse hepatocytes. We also have been analyzing past metabolomic data in a similar recording experiment on hepatocytes — exposed to BPA, DEHP, and PFOA — and linking it to metabolic diseases. In Dr. Simmons’s lab, we run western blots on liver samples, testing lipoproteins that increased in a preliminary qPCR run, from Dr. Sara Pinney’s PFOA-exposed gestational female mice and their fetuses.
What are the implications of your research?
PFOA is a per-/polyfluoroalkyl substances or PFAS, a class consisting of over 5000 chemicals and unique for its thermally and chemically stable backbone of carbon-fluorine bonds. PFAS is used for nonstick coatings and fire-fighting foams. As a result, there has been widespread contamination of this emerging and legacy contaminant in drinking water in the nation. Currently, there is no national regulation of PFAS levels in drinking water; states that have regulation over PFAS have drastic levels of tolerance, ranging from 5.1 (California, PFOA only) to 400,000 (Michigan, PFHxA) ppt.
Prevalence of PFAS found in drinking water or ground water in the USA (Source: EWG)
While PFAS does not sorb into fat tissue, it accumulates in blood, liver, lungs, kidney, and placenta with a very high human half-life. PFAS is particularly dangerous to people during windows-of-susceptibility, key developmental periods that are highly vulnerable to environmental exposures. Our specific research in Dr. Simmons’s lab focuses on the gestational period where exposures occurring at this time may result in fetal programming and cause a later onset of obesity or diabetes later in the child’s life. Consistent exposure and accumulation of PFAS may dysregulate the biological circadian clock and hormonal levels, increasing risk of developing metabolic syndrome, unbalanced energy homeostasis, and disrupted hormonal function.
What new skills have you gained through your research?
Beyond strengthening my skills in cell culture and western blot technique, I learned to analyze lipidomics data, measured using liquid chromatography mass spectroscopy. I have also learned more about how to plan experiments and troubleshoot common lab procedures. Primarily, we were challenged to set up our own western blots, optimizing the western blot procedures, antibody dilution, and protein concentration amounts.