Research to Address the Heterogeneity in Autism Spectrum Disorders (ASD) Project title: An ex-vivo placental perfusion system to study materno-fetal biology. This grant will focus on developing and validating a model system to examine the effects of alterations in materno-fetal interactions on fetal brain development. We propose that the impact of maternal immune challenges and stressors on fetal brain development is a direct consequence of altered materno-fetal interactions taking place in the placenta. Circulating maternal tryptophan metabolism in the placenta is known to be required for protecting the fetus from maternal immunity. Our preliminary results suggest that, during an early critical period of gestation, an alternative pathway of tryptophan placental metabolism also provides serotonin to the fetal circulation and therefore may be critical for normal fetal brain wiring. Advancing a new ex vivo dual perfusion model system proposed here will enable us to test the possibility that maternal immune challenges directly impact multiple placental metabolic pathways for Trp disrupting fetal supply of 5-HT and ultimately brain wiring in utero. Since placental metabolic functions change during pregnancy, we hypothesize that the degree to which maternal factors impact fetal brain development will depend on a combination of timing, nature of the challenges and also genetic susceptibility of the mother and offspring. Our ex vivo model system will provide a unique way to dissect the effect of each factor on tryptophan placental metabolism and subsequently its contribution to impacting neurobiological functions relevant to ASD such as fetal brain circuits formation. The use of mouse placentas will enable us to test the impact of altered placental metabolism in a wide array of genetic models relevant to ASD and at different stages of gestation. This is a critical advance, as it provides unique opportunities to determine how maternally derived neurotransmitters, cytokines, hormones and drugs impact the development of 5HT-relevant and other circuits that have been implicated in ASD.
Maternal-fetal interactions during the prenatal period are essential for brain development in the child. Maternal illness which increases the risk for neuropsychiatric disorders, including ASD, may impair these interactions. We propose to design and implement a new technology that will provide unique opportunities to determine how maternally derived molecules such as neurotransmitters, cytokines, hormones and drugs reach the fetal brain and impact the development of circuits that have been implicated in ASD.
