79. Arteriovenous Malformation MAP2K1-mutant Endothelial Cells Exhibit Dysregulated Vasculogenesis In-vitro And In-vivo
Year: 2024
Type: conference-abstract
Abstract: Purpose: Arteriovenous malformation (AVM) is a fast-flow vascular anomaly characterized by abnormal arterial to venous shunts causing ischemia, ulceration, pain, and bleeding. Extracranial AVMs contain a somatic mutation in the MAP2K1 gene. The purpose of this study was to: (1) create a stable MAP2K1 mutant endothelial cell (EC) line, (2) determine how the MAP2K1 mutation affects EC behavior, and (3) create in-vitro and in-vivo models to test pharmacotherapy. Methods: Utilizing CRISPR-Cas9 the MAP2K1 p.K57N mutation was introduced into immortalized arterial endothelial cells (teloHAECs). Expression of mutant transcript and elevated phosphorylated ERK (P-ERK) was tested using digital droplet PCR (ddPCR) and Western Blot. Bulk-RNAseq and differential gene expression analysis was conducted comparing mutant and control cells. Gene-edited lines were injected into immunodeficient mice and implant phenotype was characterized. In-vitro and in-vivo models were treated with a MEK inhibitor and assessed. Results: Protein analysis showed increased P-ERK in mutant cells, confirming the activating effects of the MAP2K1 mutation. Bulk-RNAseq showed increased vasculogenic gene expression between mutant and control cell lines, including a key regulator of vessel formation angiopoietin-2. Murine implants with mutant ECs displayed malformed and dilated vasculature. MEK inhibition prevented the transcriptomic and histologic effects of the MAP2K1 mutation, including reduction in angiopoietin-2 production. Conclusion: The MAP2K1 mutation in immortalized ECs activates RAS/MEK signaling, stimulates vasculogenic gene expression, and forms abnormal vascularized lesions in-vivo. These models provide insight into the pathophysiology of human AVM, enable preclinical testing of novel drug therapies, and support the efficacy of MEK inhibitors for the treatment of AVM.
Institution: Boston Children's Hospital
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,195
OpenAlex ID: W4394964937