1. Excessive vascular sprouting underlies cerebral hemorrhage in mice lacking αVβ8-TGFβ signaling in the brain
- Author
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Arnold, Thomas D, Niaudet, Colin, Pang, Mei-Fong, Siegenthaler, Julie, Gaengel, Konstantin, Jung, Bongnam, Ferrero, Gina M, Mukouyama, Yoh-suke, Fuxe, Jonas, Akhurst, Rosemary, Betsholtz, Christer, Sheppard, Dean, and Reichardt, Louis F
- Subjects
Integrins ,Mouse ,1.1 Normal biological development and functioning ,Cell Count ,Hemorrhage ,Cardiovascular ,Medical and Health Sciences ,Mice ,TGFβ ,Integrin αVβ8 ,Underpinning research ,Transforming Growth Factor beta ,TGF beta ,Animals ,2.1 Biological and endogenous factors ,Aetiology ,Neovascularization ,Cerebral Hemorrhage ,Pathologic ,Microscopy ,Analysis of Variance ,Neurosciences ,Brain ,Endothelial Cells ,Biological Sciences ,Stem Cell Research ,Immunohistochemistry ,Brain Disorders ,Stroke ,Blood-Brain Barrier ,Confocal ,Integrin alpha V beta 8 ,cardiovascular system ,Stem Cell Research - Nonembryonic - Non-Human ,Angiogenesis ,CNS ,Sprouting ,Signal Transduction - Abstract
© 2014. Published by The Company of Biologists Ltd. Vascular development of the central nervous system and blood-brain barrier (BBB) induction are closely linked processes. The role of factors that promote endothelial sprouting and vascular leak, such as vascular endothelial growth factor A, are well described, but the factors that suppress angiogenic sprouting and their impact on the BBB are poorly understood. Here, we show that integrin αVβ8 activates angiosuppressive TGFβ gradients in the brain, which inhibit endothelial cell sprouting. Loss of αVβ8 in the brain or downstream TGFβ1-TGFBR2-ALK5-Smad3 signaling in endothelial cells increases vascular sprouting, branching and proliferation, leading to vascular dysplasia and hemorrhage. Importantly, BBB function in Itgb8 mutants is intact during early stages of vascular dysgenesis before hemorrhage. By contrast, Pdgfbret/ret mice, which exhibit severe BBB disruption and vascular leak due to pericyte deficiency, have comparatively normal vascular morphogenesis and do not exhibit brain hemorrhage. Our data therefore suggest that abnormal vascular sprouting and patterning, not BBB dysfunction, underlie developmental cerebral hemorrhage.
- Published
- 2014