Author Response: Sphingosine 1-Phosphate-Regulated Transcriptomes in Heterogeneous Arterial and Lymphatic Endothelium of the Aorta

This study explored the role of sphingosine 1-phosphate receptor (S1PR1) signaling in aortic endothelial cells, using mouse models to analyze transcriptome profiles and signaling pathways. It found that S1PR signals through both ligand-dependent and independent pathways, with non-canonical signaling occurring in specific cell subsets at aortic branchpoints. The research emphasized the significance of endothelial cell heterogeneity and S1PR signaling, revealing that the unique transcriptome of arterial endothelial cells (aEC1) was likely due to cell lineage rather than flow signaling. The study also detailed the fluorescence-activated cell sorting strategy used to differentiate cell types and noted age-related increases in GFP expression in non-branch point endothelial cells. Additionally, differences in marker expression between embryonic and adult aortae were observed.