Cortisol’s Effect on Iron Transport Proteins and Extracellular Vesicles in Placental Cells

Abstract:

The importance of the placenta is often underrepresented, although it facilitates the transfer of oxygen and nutrients to the fetal bloodstream. Iron is a prominent nutrient responsible for general development, and inadequate levels have been shown to induce pregnancy complications and fetal developmental impairments. Cortisol is a stress-induced hormone found to correlate with iron levels of the blood and placenta however there are limited studies involving the effects of prolonged and excessive cortisol expressions on iron transport proteins and extracellular vesicles (EVs). EVs are intercellular communicators utilized by all cell types that function to contain bioactive cargo released during both normal and pathological cellular activities. Based on the current gaps in knowledge, the first aim of our experiment is to determine the effects of cortisol exposure in placental cell (trophoblast) derived iron transport proteins, Transferrin Receptor 1 (TFR-1), and Ferroportin 1 (FPN-1). The second aim is to effectively isolate EVs from control and cortisol exposed trophoblasts to examine whether the iron transport proteins are associated with EVs. The experiments were conducted by culturing the BeWo placental trophoblast cell line. We first conducted a dose-response study to assess cell viability and death after cortisol exposure, using the CCK8 and LDH assays, respectively. Size exclusion chromatography was then used to isolate EVs from the conditioned cell culture media of control and cortisol exposed BeWo cells, and Western blotting was used to identify the proteins of interest. Our preliminary data suggest that TFR-1 expression is upregulated and FPN-1 expression is downregulated in cells exposed to cortisol. EV associated TFR-1 is present in both the control and cortisol exposed samples, although FPN-1 is only present in control samples. Because TFR-1 is an iron importer and FPN-1 is an iron exporter, these findings may indicate an iron accumulation within the trophoblast layer of the placenta. Iron accumulations can cause oxidative stress or hypoxia among varying cell types, so prolonged excessive cortisol exposure may adversely affect the placenta.