Monosodium glutamate (MSG) perturbs trophoblast differentiation and invasion program through a ROS-mediated pathway

Monosodium glutamate (MSG) is a flavor-enhancing food additive widely used in Asian cuisine. It is one of the common ingredients used in curry and other tinned food that is believed to bring out the "umami" meat flavor and enhance the savory taste of the food. It is the sodium salt of the naturally occurring amino acid Glutamate. Due to its massive consumption as part of fast-food culture along with concerns about its possible effect on health in general and pregnancy in particular, we undertook this study to address its impact on placental trophoblast cells. We investigated the effect of MSG on placental trophoblast cells. Our studies confirmed that short and long-term exposure to MSG has a profound influence on trophoblast invasion and differentiation, two of the most critical and dispensable functions during placentation. Our results showed an acute short-term MSG-treatment enhanced trophoblast invasion and cell motility along with an increased expression in trophoblast cell differentiation markers. However, a long-term chronic MSG stimulation in these cell types showed an opposite effect with both reduced invasion and differentiation. Further, MSG-treated placental explants displayed signs of an elevated oxidative stress. These effect of MSG on trophoblast cells along with an increased ROS production indicates that short and long-term usage of MSG as part of food additive might have adverse health consequences on the fetus by compromising the trophoblast and placental function.