title: Extracellular RNA mediates endothelial-cell permeability via vascular endothelial growth factor.
abstract: Cell injury leads to exposure of intracellular material and is associated with increased permeability of vessels in the vicinity of the damage. Here, we demonstrate that natural extracellular RNA as well as artificial RNA (poly-I:C), or single-stranded RNA but not DNA, significantly increased the permeability across brain microvascular endothelial cells in vitro and in vivo. RNA-induced hyperpermeability of tight monolayers of endothelial cells correlated with disintegration of tight junctions and was mediated through vascular endothelial growth factor (VEGF), reminiscent of heparin's activities. Antisense oligonucleotides against VEGF-receptor 2 (VEGF-R2) prevented the permeability-inducing activity of extracellular RNA and heparin completely. Hence, these polyanionic substances can lead to mobilization/stabilization of VEGF with the subsequent activation of VEGF-R2. In accordance with these functional data, strong binding of VEGF as well as other growth factors to RNA was demonstrable. In in vivo rat models of FeCl(3)-induced sinus sagittal is superior thrombosis and stroke/brain edema, pretreatment of animals with RNase (but not DNase) resulted in a significant reduction of vessel occlusion, infarct volume, and prevention of brain edema formation. Together, these results identify extracellular RNA as a novel natural permeability factor, upstream of VEGF, whereas counteracting RNase treatment may serve as new vessel-protective modality.
authors.affiliation: Department of Biochemistry Medical School, Justus-Liebig-University, Giessen, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Fischer
authors.forename: Tibo
authors.initials: T
authors.lastname: Gerriets
authors.forename: Carina
authors.initials: C
authors.lastname: Wessels
authors.forename: Maureen
authors.initials: M
authors.lastname: Walberer
authors.forename: Sawa
authors.initials: S
authors.lastname: Kostin
authors.forename: Erwin
authors.initials: E
authors.lastname: Stolz
authors.forename: Kirila
authors.initials: K
authors.lastname: Zheleva
authors.forename: Andreas
authors.initials: A
authors.lastname: Hocke
authors.forename: Stefan
authors.initials: S
authors.lastname: Hippenstiel
authors.forename: Klaus T
authors.initials: KT
authors.lastname: Preissner
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000201:enzymology / Q000473:pathology; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism*; D004789:Enzyme Activation; D006493:Heparin / Q000494:pharmacology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D012313:RNA / Q000235:genetics*; D051381:Rats; D012260:Ribonucleases / Q000378:metabolism; D013927:Thrombosis / Q000201:enzymology / Q000473:pathology; D019108:Tight Junctions / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
chemical_list: D042461:Vascular Endothelial Growth Factor A; D012313:RNA; D006493:Heparin; D020928:Mitogen-Activated Protein Kinases; D012260:Ribonucleases