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Proc Natl Acad Sci U S A. 2015 Aug 11;112(32):9914-9. doi: 10.1073/pnas.1509047112. Epub 2015 Jul 28.

Endothelial depletion of murine SRF/MRTF provokes intracerebral hemorrhagic stroke.

Author information

1
Department of Molecular Biology, Interfaculty Institute of Cell Biology, University of Tuebingen, 72076 Tuebingen, Germany; alfred.nordheim@uni-tuebingen.de christine.weinl@uni-tuebingen.de Eric.Olson@utsouthwestern.edu.
2
Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University Hospital Tuebingen, 72076 Tuebingen, Germany;
3
Department of Molecular Biology, Interfaculty Institute of Cell Biology, University of Tuebingen, 72076 Tuebingen, Germany;
4
Department of Pathology and Neuropathology, University of Tuebingen, 72076 Tuebingen, Germany;
5
Institute for Animal Pathology, Department of Veterinary Pathology, Free University Berlin, 14163 Berlin, Germany;
6
Institut de Génétique et de Biologie Moléculaire et Cellulaire, 67400 Illkirch, France; Centre National de la Recherche Scientifique, UMR 7104, 67404 Illkirch, France; Institut National de la Santé et de la Recherche Médicale, U964, 67400 Illkirch, France; Université de Strasbourg, 67400 Illkirch, France;
7
Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390; alfred.nordheim@uni-tuebingen.de christine.weinl@uni-tuebingen.de Eric.Olson@utsouthwestern.edu.
8
Department of Tissue Morphogenesis, Max-Planck-Institute for Molecular Biomedicine and Faculty of Medicine, University of Muenster, 48149 Muenster, Germany.

Abstract

Intracerebral hemorrhagic stroke and vascular dementia are age- and hypertension-associated manifestations of human cerebral small vessel disease (SVD). Cerebral microvessels are formed by endothelial cells (ECs), which are connected through tight junctions, adherens junctions, and stabilizing basement membrane structures. These endothelial connections ensure both vessel stability and blood-brain barrier (BBB) functions, the latter enabling selective exchange of ions, bioactive molecules, and cells between the bloodstream and brain tissue. Srf(iECKO) mice, permitting conditional EC-specific depletion of the transcription factor Serum Response Factor (SRF), suffer from loss of BBB integrity and intracerebral hemorrhaging. Cerebral microbleeds and larger hemorrhages developed upon postnatal and adult depletion of either SRF or its cofactors Myocardin Related Transcription Factor (MRTF-A/-B), revealing essential requirements of ongoing SRF/MRTF activity for maintenance of cerebral small vessel integrity. In vivo magnetic resonance imaging allowed detection, localization, and time-resolved quantification of BBB permeability and hemorrhage formation in Srf(iECKO) brains. At the molecular level, direct and indirect SRF/MRTF target genes, encoding structural components of tight junctions (Claudins and ZO proteins), adherens junctions (VE-cadherin, α-Actinin), and the basement membrane (Collagen IV), were down-regulated upon SRF depletion. These results identify SRF and its MRTF cofactors as major transcriptional regulators of EC junctional stability, guaranteeing physiological functions of the cerebral microvasculature. We hypothesize that impairments in SRF/MRTF activity contribute to human SVD pathology.

KEYWORDS:

blood–brain barrier; cerebral microbleeds; conditional gene knockout; stroke mouse model; transcription

PMID:
26221020
PMCID:
PMC4538672
DOI:
10.1073/pnas.1509047112
[Indexed for MEDLINE]
Free PMC Article

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