IntroductionBlood pressure (BP) is a highly heritable trait with over two thousand underlying genomic loci identified to date. While the kidney plays a key role, little is known about specific cell types involved in the genetic regulation of BP. MethodsHere, we applied stratified linkage disequilibrium score (LDSC) regression to connect blood pressure GWAS results to specific cell types of the mature human kidney. We used the largest single-stage BP genome-wide analysis to date, including up to 1,028,980 adults of European ancestry, and single-cell transcriptomic data from 14 mature human kidneys, 41 years mean of age. ResultsOur analyses prioritized myofibroblasts and endothelial cells, among the total of 33 annotated cell type, as specifically involved in BP regulation (p-value < 0.05/33 i.e., 0.001515). Enrichment of heritability for systolic BP was observed in myofibroblast cells in mature human kidney cortex, and enrichment of heritability for diastolic BP was observed in descending vasa recta and peritubular capillary endothelial cells as well as stromal myofibroblast cells. The new finding of myofibroblast, the significant cell type for both BP traits, was consistent in eight replication efforts using seven sets of independent data, including in human fetal kidney, in East Asian ancestry, using mouse scRNA-seq data, and when using another prioritization method. ConclusionsOur findings provide a solid basis for follow up studies to further identify genes and mechanisms in myofibroblast cells that underlie the regulation of BP.