DESCRIPTION (provided by applicant): Promoting vascular remodeling has emerged as a potential therapeutic approach for neurorestorative therapy. Cerebral vascular trauma leads to inadequate cerebral blood flow which potentiates neuronal cell loss resulting in motor and cognitive deficits in models of brain injury. Endothelial cells (ECs) lining the blood vessels actively respond to tissue trauma. Our novel findings demonstrate, cell-to-cell contact proteins called Eph receptor tyrosine kinases (EphR), and their ephrin ligand(s), are present on cerebral arteriole ECs and play a central role in limiting arteriogenesis in the murine brain following injury. The research objectives in this application focus on the novel growth suppressive mechanism(s) of EphR signaling on arteriole remodeling and neural recovery. Endothelial-specific deletion of EphR resulted in significant neuroprotection and restoration of blood flow which reflects a monumental change in arteriogenic growth and production of pro-arteriogenic factors. We hypothesize that activation of EphR signaling mediates neural tissue damage and dysfunction by suppressing the EC response during arteriole vascular remodeling. To test this, we will employ novel cell-specific and inducible knockout mice, double reporter labeling and adoptive transfer. We will also investigate the relevance and mechanisms of injury-induced arteriogenesis in neural recovery using gain- and reverse-of-function infusion approaches. These studies will reveal a novel therapeutic strategy to enhance this important adaptive process which will greatly impact treatment and management of acute and chronic head injuries.