Increased endothelial cell permeability in endoglin‐deficient cells

• Published in: The FASEB journal 2015-09, Vol.29 (9), p.3678-3688
• Main Authors: Jerkic, Mirjana, Letarte, Michelle
• Format: Article
• Language: English
• Subjects: Animals; Capillary Permeability; Cell Line; Embryo, Mammalian - cytology; Embryo, Mammalian - metabolism; Endoglin; Endothelial Cells - cytology; Endothelial Cells - metabolism; Intracellular Signaling Peptides and Proteins - deficiency; Intracellular Signaling Peptides and Proteins - genetics; Mice; Mice, Knockout; rho GTP-Binding Proteins - genetics; rho GTP-Binding Proteins - metabolism; RhoA; TGF‐β1; Thrombospondin 1 - genetics; Thrombospondin 1 - metabolism; Transforming Growth Factor beta1 - genetics; Transforming Growth Factor beta1 - metabolism; TSP‐1; Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; Vascular Endothelial Growth Factor Receptor-2 - genetics; Vascular Endothelial Growth Factor Receptor-2 - metabolism; VEGF
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fj.14-269258

ABSTRACT Endoglin (ENG) is a TGF‐β superfamily coreceptor essential for vascular endothelium integrity. ENG mutations lead to a vascular dysplasia associated with frequent hemorrhages in multiple organs, whereas ENG null mouse embryos die at midgestation with impaired heart development and leaky vasculature. ENG interacts with several proteins involved in cell adhesion, and we postulated that it regulates vascular permeability. The current study assessed the permeability of ENG homozygous null (Eng‐/‐), heterozygous (Eng+/‐), and normal (Eng+/+) mouse embryonic endothelial cell (EC) lines. Permeability, measured by passage of fluorescent dextran through EC monolayers, was increased 2.9‐ and 1.7‐fold for Eng‐/‐ and Eng+/‐ ECs, respectively, compared to control ECs and was not increased by TGF‐p 1 or VEGF. Prolonged starvation increased Eng‐/‐ EC permeability by 3.7‐fold with no effect on control ECs; neutrophils transmigrated faster through Eng‐/‐ than Eng+/+ monolayers. Using a pull‐down assay, we demonstrate that Ras homolog gene family (Rho) Ais constitutively active in Eng‐/‐ and Eng+/‐ECs. We show that the endothelial barrier destabilizing factor thrombospondin‐1 and its receptor‐like protein tyrosine phosphatase are increased, whereas stabilizing factors VEGF receptor 2, vascular endothelial‐cadherin, p21‐activated kinase, and Ras‐related C3 botulinum toxin substrate 2 are decreased in Eng‐/‐ cells. Our findings indicate that ENG deficiency leads to EC hyper‐permeability through constitutive activation of RhoA and destabilization of endothelial barrier function.—Jerkic, M., Letarte, M. Increased endothelial cell permeability in endoglin‐deficient cells. FASEB J. 29, 3678‐3688 (2015). www.fasebj.org