BACKGROUND: Preeclampsia is a hypertensive disorder of pregnancy characterized by systemic endothelial dysfunction. The pathophysiology of preeclampsia remains incompletely understood. This study used human venous endothelial cell (EC) transcriptional profiling to investigate potential novel mechanisms underlying EC dysfunction in preeclampsia. METHODS: Venous ECs were isolated from postpartum patients with severe preeclampsia and those with normotensive pregnancy using a J wire–based technique in the antecubital vein followed by CD144 magnetic bead isolation. Venous EC transcriptomes were compared between preeclamptic and normotensive individuals. Differentially expressed genes were carried forward for genetic validation using expression quantitative trait loci from the Genotype-Tissue Expression project as exposures for vascular-specific Mendelian randomization. Functional validation of the top candidate was performed in human umbilical vein ECs using gain- and loss-of-function genet