title: Impaired caveolae function and upregulation of alternative endocytic pathways induced by experimental modulation of intersectin-1s expression in mouse lung endothelium.
abstract: Intersectin-1s (ITSN-1s), a protein containing five SH3 (A-E) domains, regulates via the SH3A the function of dynamin-2 (dyn2) at the endocytic site. ITSN-1s expression was modulated in mouse lung endothelium by liposome delivery of either a plasmid cDNA encoding myc-SH3A or a specific siRNA targeting ITSN-1 gene. The lung vasculature of SH3A-transduced and ITSN-1s- deficient mice was perfused with gold albumin (Au-BSA) to analyze by electron microscopy the morphological intermediates and pathways involved in transendothelial transport or with dinitrophenylated (DNP)-BSA to quantify by ELISA its transport. Acute modulation of ITSN-1s expression decreased the number of caveolae, impaired their transport, and opened the interendothelial junctions, while upregulating compensatory nonconventional endocytic/transcytotic structures. Chronic inhibition of ITSN-1s further increased the occurrence of nonconventional intermediates and partially restored the junctional integrity. These findings indicate that ITSN-1s expression is required for caveolae function and efficient transendothelial transport. Moreover, our results demonstrate that ECs are highly adapted to perform their transport function while maintaining lung homeostasis.
authors.affiliation: Department of Pharmacology, Rush University, 1735 W Harrison, Chicago, IL 60612, USA.
authors.forename: Dan N
authors.initials: DN
authors.lastname: Predescu
authors.forename: Radu
authors.initials: R
authors.lastname: Neamu
authors.forename: Cristina
authors.initials: C
authors.lastname: Bardita
authors.forename: Minhua
authors.initials: M
authors.lastname: Wang
authors.forename: Sanda A
authors.initials: SA
authors.lastname: Predescu