Journal: bioRxiv
Article Title: Sphingosine-1-phosphate cross-talks to Notch via a S1PR1-Dll4-MPDZ complex to regulate endothelial barrier function
doi: 10.64898/2026.05.20.726610
Figure Lengend Snippet: a , Immunoblots showing cleaved Notch1 (c-Notch1) and total Notch1 in MVECs treated with S1P for 1-hour ± γ-secretase inhibitor DAPT; quantification below (mean ± SEM). b , Fluorescent micrographs of YFP-Notch1 reporter intensity after S1P treatment; quantification below. Scale bar, 50 μm. c-d , Fold change in HES1 and HEY1 gene expression levels in (c) MVECs after S1P ± DAPT treatment, and in (d) mouse tissues after intravenous injection of S1P ± DAPT. e , Evans blue dye leakage in mouse dermis 1-hour post-injection with DMSO, S1P, or S1P + DAPT. Scale bar, 5 mm. f-i , Quantified dye leakage in (f) dermis, (g) lung, (h) liver, and (i) kidney, measured via absorbance. j , Heat maps of dextran dye diffusion in engineered microvessels ± S1P. Scale bar, 50 μm. k-l , Diffusive permeability in microvessels lined with (k) DAPT-vs. DMSO-treated or (l) NOTCH1 KO vs. SCR KO MVECs (mean ± SD). m , Micrographs of VE-cadherin (magenta), actin (green), and nuclei (blue) staining in microvessels. Scale bar, 50 μm. n-o , Mean corrected intensities of junctional (n) VE-cadherin and (o) actin from (m). p , Rac1 activity (PBD pull-down). Active/total Rac1 quantification below. q , Schematic of canonical Notch signaling. r , HES1 / HEY1 gene expression levels in dominant negative-MAML-GFP (DN-MAML-GFP) normalized to GFP expressing cells. s , Permeability in DN-MAML-GFP vs GFP-lined microvessels ± S1P. t , Schematic of Notch cortical pathway mediated by its transmembrane domain (TMD). u , Permeability in TMD-RFP vs RFP-lined microvessels ± S1P. v , Permeability in TMD-RFP vs RFP-lined microvessels ± clinical S1P receptor degrader fingolimod.
Article Snippet: PAK-PBD beads to bind active Rac1 (PAK-02) were purchased from Cytoskeleton and reconstituted according to the manufacturer’s instructions.
Techniques: Western Blot, Gene Expression, Injection, Diffusion-based Assay, Permeability, Staining, Activity Assay, Dominant Negative Mutation, Expressing
