PROJECT SUMMARY: Neurodevelopmental impairment remains the most vexing issue facing the clinical management of premature infants. Intrauterine infection and inflammation are significant causes of preterm birth potentially resulting in lifelong neurodevelopmental impairment, such as cerebral palsy, sensory and cognitive deficits and behavioral difficulties. Ureaplasma is a bacterial species that is a common cause of preterm labor and non-human primates (NHP) are the most clinically relevant animal model in which to study human preterm labor and fetal brain injury. Our unique chronically catheterized rhesus monkey model allows constant physiological monitoring and longitudinal sampling of amniotic, maternal and fetal compartments and evaluation of treatments longitudinally across gestation. In our previous NHP studies, antibiotic treatment (Azithromycin) of intrauterine infection with Ureaplasma has been shown to delay preterm labor and improve fetal lung and hemodynamic outcomes. Novel immunomodulatory drugs proposed for the treatment of preterm labor would need to be combined with antimicrobials such as Azithromycin in the setting of intrauterine infection. However, mechanisms of perinatal brain injury and the action of antibiotics on the fetal brain in relation to intrauterine infection remain poorly understood. Therefore, the objective of this proposal is to determine how Azithromycin treatment may modulate fetal neuroinflammation caused by intrauterine Ureaplasma infection, to improve fetal neurodevelopmental outcomes. Data from our previous NHP studies of intrauterine Ureaplasma infection added to this resubmission includes evidence of: i) placental membrane inflammation and inflammasome activation; ii) maternal Azithromycin treatment normalization of fetal blood flow; and iii) preliminary data that fetal brain microglial activation is fully reversed by azithromycin treatment. We also provide NHP data for detection of fetal neural extracellular vesicle markers of perinatal brain injury. In Aim 1 we will assess physiological aspects of preterm labor and immune responses to intrauterine infection and antibiotic treatment. Aim 2 will determine fetal brain molecular, histological and spatial transcriptomic changes with Ureaplasma infection and Azithromycin treatment. In addition, we will characterize the expression of microglia/astrocyte activation phenotypes and myelin development associated with neuroinflammation. Aim 3 will investigate how fetal brain extracellular vesicles extracted from maternal blood may be used as a novel, non-invasive diagnostic tool for perinatal brain injury and for the monitoring of Azithromycin efficacy and safety. Development of novel diagnostic technologies is essential for the in vivo monitoring of fetal status in response to treatment. Using a combination of novel techniques and our clinically relevant NHP model, this proposal utilizes our team's extensive experience in studying pregnancy physiology, fetal neurode...