RESUMEN
Placental abnormalities can cause Pregnancy-Associated Disorders, including preeclampsia, intrauterine growth restriction, and placental insufficiency, resulting in complications for both the mother and fetus. Trophoblast cells within the labyrinthine layer of the placenta facilitate the exchange of nutrients, gases, and waste between mother and fetus; therefore, the development of this cell layer is critical for fetal development. As trophoblast cells differentiate, it is assumed their metabolism changes with their energy requirements. We hypothesize that proper regulation of trophoblast metabolism is a key component of normal placental development; therefore, we examined the role of AMP-activated kinase (AMPK, PRKAA1/2), a sensor of cellular energy status. Our previous studies have shown that AMPK knockdown alters both trophoblast differentiation and nutrient transport. In this study, AMPKα1/2 shRNA was used to investigate the metabolic effects of AMPK knockdown on SM10 placental labyrinthine progenitor cells before and after differentiation. Extracellular flux analysis confirmed that AMPK knockdown was sufficient to reduce trophoblast glycolysis, mitochondrial respiration, and ATP coupling efficiency. A reduction in AMPK in differentiated trophoblasts also resulted in increased mitochondrial volume. These data indicate that a reduction in AMPK disrupts cellular metabolism in both progenitors and differentiated placental trophoblasts. This disruption correlates to abortive trophoblast differentiation that may contribute to the development of Pregnancy-Associated Disorders.
Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Diferenciación Celular , Vellosidades Coriónicas/metabolismo , Metabolismo Energético , Técnicas de Silenciamiento del Gen , Células Madre/citología , Células Madre/enzimología , Adenosina Trifosfato/metabolismo , Animales , Línea Celular , Respiración de la Célula , Forma de la Célula , Tamaño de la Célula , Femenino , Glucólisis , Ratones , Mitocondrias/metabolismo , Tamaño de los Orgánulos , Embarazo , ProtonesRESUMEN
The placenta is a transient organ that develops upon the initiation of pregnancy and is essential for embryonic development and fetal survival. The rodent placenta consists of distinct lineages and includes cell types that are analogous to those that make up the human placenta. Trophoblast cells within the labyrinth layer, which lies closest to the fetus, fuse and come in contact with maternal blood, thus facilitating nutrient and waste exchange between the mother and the baby. Abnormalities of the placenta may occur as a result of cellular stress and have been associated with pregnancy-associated disorders: such as preeclampsia, intrauterine growth restriction, and placental insufficiency. Cellular stress has also been shown to alter proliferation and differentiation rates of trophoblast cells. This stress response is important for cell survival and ensures continued placental functionality. AMP-activated protein kinase is an important sensor of cellular metabolism and stress. To study the role of AMPK in the trophoblast cells, we used RNA interference to simultaneously knockdown levels of both the AMPK alpha isoforms, AMPKα1 and AMPKα2. SM10 trophoblast progenitor cells were transduced with AMPKα1/2 shRNA and stable clones were established to analyze the effects of AMPK knockdown on important cellular functions. Our results indicate that a reduction in AMPK levels causes alterations in cell morphology, growth rate, and nutrient transport, thus identifying an important role for AMPK in the regulation of placental trophoblast differentiation.