ABSTRACT This proposal describes a five-year training program and research proposal for the career development of Dr. Augusto Schmidt as a physician-scientist in Neonatology with expertise in neonatal brain injury. Dr. Schmidt completed his Pediatrics residency and Neonatology fellowship at Cincinnati Children?s Hospital and is currently Assistant Professor of Pediatrics in the Division of Neonatology at the University of Miami (UM). Dr. Schmidt is interested in determining the mechanistic relationship between mechanical ventilation and brain injury in preterm newborns, and is particularly interested in how mechanical ventilation causes the lung to release exosomes, which may induce brain cellular death and injury in preterm newborns. Dr. Schmidt will be mentored by Dr. Dalton Dietrich and Dr. Shu Wu with the support of a scientific advisory committee. Dr. Dietrich, a world-renowned expert in brain injury, will mentor Dr. Schmidt?s scientific progress and career development. Dr. Dietrich is the Director of the Miami Project to Cure Paralysis and Distinguished Chair of Neurosurgery at UM and has been committed to training scientists throughout his career having served as the principal investigator of a T32 Training Program, thesis advisor of 9 PhD students, and mentored over 30 postdoctoral fellows. Dr. Wu is a neonatologist and expert in neonatal lung injury and will complement Dr. Dietrich as a co-mentor. Dr. Wu has successfully mentored more than 20 clinical and postdoctoral fellows and medical students. The advisory committee will support Dr. Dietrich and Dr. Wu in mentoring Dr. Schmidt and will consist of Dr. Roberta Brambilla, an expert in neuroinflammation, Dr. Eduardo Bancalari, a neonatologist and expert in neonatal chronic lung disease and Dr. Alan Jobe, a neonatologist and accomplished physician-scientist, who has previously mentored Dr. Schmidt. In this proposal, Dr. Schmidt will test the hypothesis that mechanical ventilation causes the lung to release exosomes containing caspase-1 and that these exosomes cross the blood-brain barrier to activate Gasdermin D (GSDMD) in the brain, inducing cellular death and brain injury. Dr. Schmidt will use a survival model of neonatal rodent ventilation to test the following aims: (1) to determine the mechanistic function of GSDMD in inducing neuronal cell death in ventilation-associated brain injury (VABI); (2) to determine the mechanistic function of pulmonary-derived exosomal caspase-1 in activating neuronal GSDMD in VABI. Dr. Schmidt will use a combination of pharmacological and genetic loss-of function mice models for GSDMD and caspase-1 to address these aims. Brain injury and cellular death will be determined by a combination of techniques including immunohistochemistry, western blotting, ELISA, and real time-PCR. Long-term outcomes will be assessed by neurobehavioral testing. These pharmacological and genetic approaches will delineate the role of the exosomal caspase-1 / neuronal GSDMD pathway in the development of VABI. This research will provide insight into new pathways for therapeutic intervention to prevent or treat brain injury in ventilated preterm newborns and provide the foundation for Dr. Schmidt?s research career focused on neonatal brain injury.