Abstract
Endothelial cell-cell junctions regulate vascular permeability, vasculogenesis, and angiogenesis. Familial cerebral cavernous malformations (CCMs) in humans result from mutations of CCM2 (malcavernin, OSM, MGC4607), PDCD10 (CCM3), or KRIT1 (CCM1), a Rap1 effector which stabilizes endothelial cell-cell junctions. Homozygous loss of KRIT1 or CCM2 produces lethal vascular phenotypes in mice and zebrafish. We report that the physical interaction of KRIT1 and CCM2 proteins is required for endothelial cell-cell junctional localization, and lack of either protein destabilizes barrier function by sustaining activity of RhoA and its effector Rho kinase (ROCK). Protein haploinsufficient Krit1(+/-) or Ccm2(+/-) mouse endothelial cells manifested increased monolayer permeability in vitro, and both Krit1(+/-) and Ccm2(+/-) mice exhibited increased vascular leak in vivo, reversible by fasudil, a ROCK inhibitor. Furthermore, we show that ROCK hyperactivity occurs in sporadic and familial human CCM endothelium as judged by increased phosphorylation of myosin light chain. These data establish that KRIT1-CCM2 interaction regulates vascular barrier function by suppressing Rho/ROCK signaling and that this pathway is dysregulated in human CCM endothelium, and they suggest that fasudil could ameliorate both CCM disease and vascular leak.
Publication types
-
Research Support, N.I.H., Extramural
MeSH terms
-
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / analogs & derivatives
-
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / pharmacology
-
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / therapeutic use
-
Animal Structures / blood supply
-
Animal Structures / metabolism
-
Animals
-
Brain Edema / drug therapy
-
Brain Edema / genetics
-
Brain Edema / pathology
-
Capillary Permeability / drug effects
-
Capillary Permeability / physiology*
-
Carrier Proteins / genetics
-
Carrier Proteins / metabolism*
-
Edema, Cardiac / drug therapy
-
Edema, Cardiac / genetics
-
Edema, Cardiac / pathology
-
Endothelial Cells / drug effects
-
Endothelial Cells / metabolism
-
Endothelium, Vascular / drug effects
-
Endothelium, Vascular / metabolism
-
Endothelium, Vascular / pathology
-
Hemangioma, Cavernous, Central Nervous System / drug therapy
-
Hemangioma, Cavernous, Central Nervous System / metabolism
-
Hemangioma, Cavernous, Central Nervous System / pathology
-
Humans
-
KRIT1 Protein
-
Mice
-
Mice, Inbred C57BL
-
Mice, Mutant Strains
-
Microfilament Proteins / genetics
-
Microfilament Proteins / metabolism*
-
Microtubule-Associated Proteins / genetics
-
Microtubule-Associated Proteins / metabolism
-
Mutation / physiology
-
Myosin Light Chains / metabolism
-
Phosphorylation / drug effects
-
Phosphorylation / genetics
-
Protein Binding / physiology
-
Protein Kinase Inhibitors / pharmacology
-
Protein Kinase Inhibitors / therapeutic use
-
Proto-Oncogene Proteins / genetics
-
Proto-Oncogene Proteins / metabolism
-
Pulmonary Edema / genetics
-
Pulmonary Edema / pathology
-
RNA, Small Interfering / genetics
-
Signal Transduction / drug effects
-
Signal Transduction / physiology*
-
rho-Associated Kinases / antagonists & inhibitors
-
rho-Associated Kinases / metabolism
-
rhoA GTP-Binding Protein / metabolism*
Substances
-
2-methyl-1-((4-methyl-5-isoquinolinyl)sulfonyl)homopiperazine
-
CCM2 protein, human
-
Carrier Proteins
-
KRIT1 Protein
-
KRIT1 protein, human
-
Krit1 protein, mouse
-
Microfilament Proteins
-
Microtubule-Associated Proteins
-
Myosin Light Chains
-
Protein Kinase Inhibitors
-
Proto-Oncogene Proteins
-
RNA, Small Interfering
-
osmosensing scaffold for MEKK3 protein, mouse
-
RHOA protein, human
-
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine
-
rho-Associated Kinases
-
rhoA GTP-Binding Protein
-
fasudil