Molecular and cellular etiology of cerebral cavernous malformations

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DESCRIPTION (provided by applicant): This project aims to elucidate pathogenetic mechanisms in cerebral cavernous malformations (CCMs), a clinical syndrome in the brain and spinal cord marked by venous sinusoids that predispose to intracranial hemorrhage. Three genes have been identified as causes of CCMs; KRIT1 (CCM1), MGC4607 (CCM2), and PDCD10 (CCM3), which when mutated leads to the formation of neurovascular malformations. We propose that CCM genes regulate beta1 integrin-mediated signaling pathways during angiogenesis, remodeling, and/or homeostasis of the microvasculature and that perturbation of this process contributes to the development of CCMs. We have specifically silenced krit1 expression in cultured human vascular endothelial cells and observed dramatic perturbations in cellular proliferation, motility, and survival. We have also demonstrated: 1) interaction of krit1 with icap1alpha, a known mediator of beta1 integrin signaling; 2) interaction of krit1 with MGC4607; 3) perturbation of cultured endothelial cell proliferation, migration, and survival accompanied by reduced signaling through focal adhesion kinase (FAK), Rac1, and integrin-linked kinase (ILK) cascades, respectively, after siRNA-mediated silencing of either krit1 or icap1alpha; 4) enhancement of multiple beta1 integrin signaling cascades through targeting icap1 to the cell membrane; and 5) failed nuclear localization and degradation of icap1alpha and MGC4607 after silencing of krit1; 6) well documented cardiovascular defects of Ccm1 (santa, san) and Ccm2 (valentine, vtn) zebrafish, and 7) perturbation of vasculatures due to increased vascular endothelial cell apoptosis in san zebrafish. In this research project, we will focus on three critical areas: 1). Isolation of the GFP-labeled vascular endothelial cells during pathogenesis of zebrafish Ccms; 2). The elucidation of the role of Ccm genes in the angiogenesis/vasculogenesis with multiple genomic and proteomic analysis of the vascular endothelial cells during pathogenesis of zebrafish CCMs; and 3) identification of other cellular factors interacting of krit1, MGC4607, and PDCD10 during microvascular angiogenesis. This animal research will provide detailed knowledge regarding the cellular role of CCM genes and their complex in vascular endothelial cells during angiogenesis, a critical first step in the development of nonsurgical therapeutic strategies for microvascular malformations. PUBLIC HEALTH RELEVANCE: Cerebral cavernous malformations (CCMs) is a vascular syndrome in the brain that causes stroke. CCMs occur in approximately 0.5% of the population and represent 10% of all vascular malformations. Since CCM is the major cause for seizures among Hispanic ethnic group which contributes to over 85% population in El Paso, our proposed genomic and proteomic study on animal model is not only essential for understanding the molecular pathogenesis of this disease, but also extremely important for regional public health.