Role of Gasdermin-D in neonatal hyperoxia-induced systemic vascular remodeling and cardiac dysfunction - PROJECT SUMMARY The population of preterm survivors has significantly increased due to advancements in neonatal care. However, these individuals are later at risk for cardiovascular morbidities such as hypertension, ischemic heart disease, and heart failure, which poses a global public health concern. Preterm infants often receive supraphysiological levels of oxygen or hyperoxia to ensure adequate oxygen saturation, which can lead to neonatal inflammation- a strong predictor of vascular injury. This neonatal hyperoxia negatively impacts the immature vascular system, causing inflammation and vascular dysfunction later in life; however, the underlying mechanisms are essentially unknown. Currently, there are no therapies to prevent vascular consequences of preterm birth. Gasdermin D (GSDMD) is a cytosolic protein that plays a key role in the vascular inflammatory response and mediates pyroptosis, a form of programmed inflammatory cell death, forming pores in the cell membrane to release pro- inflammatory cytokines. Our preliminary data using a neonatal hyperoxia mouse model that mimics preterm- related neonatal morbidities indicate that neonatal hyperoxia increases vascular inflammation by upregulating pro-inflammatory GSDMD. In contrast, downregulating GSDMD decreases vascular inflammation and improves cardiovascular outcomes such as vascular stiffness, remodeling and elevated blood pressure in adult mice exposed to neonatal hyperoxia, suggesting an important mechanistic link. Based on our preliminary data, we hypothesize that the downregulation of GSDMD protects against neonatal hyperoxia-induced vascular remodeling and cardiac dysfunction. The primary goal of this proposal is to target GSDMD in neonatal hyperoxia-induced vascular dysfunction and identify how endothelial GSDMD downregulation improves neonatal hyperoxia-induced vascular outcomes. We test our hypothesis in two specific aims (SA): SA1: Test the hypothesis that GSDMD deficiency improves neonatal hyperoxia-induced short-term and long-term systemic vascular remodeling and cardiac function. Here, we will investigate whether genetic deletion and pharmacological inhibition of GSDMD in room air or hyperoxia-exposed neonatal mice will improve vascular remodeling and cardiac function in neonatal and adult mice. We will assess vascular stiffness, remodeling, blood pressure, cardiac function, angiogenesis, and perform molecular studies. SA2: Test the hypothesis that loss of GSDMD, specifically in endothelial cells, ameliorates neonatal hyperoxia-induced vascular outcomes. Here, we assess whether endothelial-specific deletion of GSDMD will ameliorate hyperoxia-induced vascular inflammation, pyroptosis, vascular remodeling, fibrosis and cardiac function in neonatal and adult mice. This study will bring new insight into the role of GSDMD in neonatal hyperoxia-induced vascular dysfunction and translate these findings into a new therapeutic approach to treat vascular consequences of preterm birth.
