Autophagy and Intracellular Trafficking in Placental Biology

National Institute Of Environmental Health Sciences

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Abstract

Inactivation of autophagy genes in mouse models causes increased embryonic or fetal death, supporting an essential role of autophagy in embryonic development. Central to the embryo's survival is the formation of the placenta. This organ gains access to the maternal blood supply and facilitates the physiological exchange between the fetus and the maternal tissues. The placenta relies on a variety of specialized cells, called trophoblasts, and pathways that are essential for creating a sensing and physical barrier between the fetus and the mother. Accordingly, autophagy is believed to play a critical role in placental development, monitoring all the challenges the embryo faces while adapting to the new maternal environment. The main goal of our research plan is to identify specific autophagy machinery required for placental development and maintenance during pregnancy. When the placenta does not work properly, both mother and fetus display a variety of complex systemic disorders. An example is preeclampsia, where affected pregnant women develop hypertension and proteinuria along with systemic endothelial dysfunction during the second half of pregnancy and sometimes beyond delivery. Additionally, preeclampsia is sometimes associated with fetal growth restriction and stillbirth, conditions that critically impact the proper intra-uterine fetal development and have long-term adverse consequences later in the life of the child. The mechanisms that contribute to cardiovascular and renal disease following preeclampsia, unfortunately, are unclear. This year, our group generated several floxed and null murine alleles to study placental-specific functions of autophagy, and we established a protocol to obtain de-identified human placentas from a local hospital at UNC-Chapel Hill to isolate trophoblast and culture them in vitro as a central tool for our efforts. We will use these models to further our understanding of placenta development and function using different microscopy (cryo-electron and fluorescence) techniques and advanced biochemical approaches. Additionally, we set up a protocol to isolate extracellular vesicles (EVs) and characterize them in autophagy-knock-out trophoblast cell lines. These studies will allow us to fully characterize the role of autophagy in secretion and find novel regulators of such activity in the placenta. Finally, we synthesized and tested several functionalized PFAS in order to study their cellular localization and toxic effects on the cell. These experiments will allow us to finally decipher and interpret the cytotoxicity of PFAS at the cellular and molecular levels.