Drug Development for Pediatric Capillary Malformation

点击翻译按钮获取中文摘要

Project Summary This grant application is focused on capillary malformation (CM), a sporadic, non-hereditary vascular anomaly affecting 1/300 newborns. CMs are present at birth and may affect any area of skin. They grow darker and thicker over time. The lesions contain excessive, enlarged capillary-like vessels and cause soft-tissue and skeletal overgrowth. Patients suffer severe psychosocial morbidity from the appearance of the lesions and associated overgrowth can cause bleeding and functional disability. Sturge-Weber syndrome (SWS) affects 1 in 20,000 to 50,000 individuals and is characterized by a facial CM with extension to either the brain and/or eyes. Patients with SWS may develop neurological impairment, seizures, glaucoma, and blindness. CM is caused by a somatic activating mutation in GNAQ (p.R183Q) that is enriched in the endothelial cell (EC). GNAQ encodes Gαq, the α- subunit of the heterotrimeric Gq protein that activates phospholipase Cβ. The overactivation of Gαq leads to a strong increase in ANGPT2 expression. Drugs do not exist for CM and management consists of pulse-dye laser to lighten its color and surgical removal. Seizures in SWS are controlled by anti-epileptic drugs. Pharmacotherapy is desperately needed to prevent CM progression and recurrence following traditional treatments. Completion of these studies will be major steps towards this goal. Aim 1 will create a cell-based assay for EC dysfunction in CM/SWS using GFP knocked into the ANGPT2 locus as an easily detectable readout. We will use this cell system for high-throughput screening of FDA- approved drugs and bioactive compounds. This could lead to the identification of druggable pathways. Our understanding of how CM forms and grows, as well as our ability to test potential drug treatments, is hampered by the absence of a mouse model. Aim 2 will focus on creating CMs in mice. We have generated a mouse line in which we can activate expression of Gαq-R183Q in ECs using Cdh5CreER. To turn on Gαq-R183Q expression in a manner that produces CMs resembling the human condition we will use topical tamoxifen. We will test different doses of tamoxifen and time points (new-born to adult). We also will induce CM formation by injection of Adenovirus-Cdh5Cre into the limbs of prenatal and postnatal animals, as well as into the brain of ROSA-GT-GNAQ-R183Q animals to obtain a SWS phenotype. Creation of an animal model will enable future studies to test drug candidates from Aim 1 for their ability to stop the formation and growth of CMs. The most efficacious drugs will be translated to humans and undergo clinical trials.