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Endothelial cell-restricted disruption of FoxM1 impairs endothelial repair following LPS-induced vascular injury.

ABSTRACT: Recovery of endothelial integrity after vascular injury is vital for endothelial barrier function and vascular homeostasis. However, little is known about the molecular mechanisms of endothelial barrier repair following injury. To investigate the functional role of forkhead box M1 (FoxM1) in the mechanism of endothelial repair, we generated endothelial cell-restricted FoxM1-deficient mice (FoxM1 CKO mice). These mutant mice were viable and exhibited no overt phenotype. However, in response to the inflammatory mediator LPS, FoxM1 CKO mice displayed significantly protracted increase in lung vascular permeability and markedly increased mortality. Following LPS-induced vascular injury, FoxM1 CKO lungs demonstrated impaired cell proliferation in association with sustained expression of p27(Kip1) and decreased expression of cyclin B1 and Cdc25C. Endothelial cells isolated from FoxM1 CKO lungs failed to proliferate, and siRNA-mediated suppression of FoxM1 expression in human endothelial cells resulted in defective cell cycle progression. Deletion of FoxM1 in endothelial cells induced decreased expression of cyclins, Cdc2, and Cdc25C, increased p27(Kip1) expression, and decreased Cdk activities. Thus, FoxM1 plays a critical role in the mechanism of the restoration of endothelial barrier function following vascular injury. These data suggest that impairment in FoxM1 activation may be an important determinant of the persistent vascular barrier leakiness and edema formation associated with inflammatory diseases.

SUBMITTER: Zhao YY

PROVIDER: S-EPMC1555637 | biostudies-literature | 2006 Sep

REPOSITORIES: biostudies-literature

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Endothelial cell-restricted disruption of FoxM1 impairs endothelial repair following LPS-induced vascular injury.

Zhao You-Yang YY Gao Xiao-Pei XP Zhao Yidan D YD Mirza Muhammad K MK Frey Randall S RS Kalinichenko Vladimir V VV Wang I-Ching IC Costa Robert H RH Malik Asrar B AB

The Journal of clinical investigation 20060901 9

Recovery of endothelial integrity after vascular injury is vital for endothelial barrier function and vascular homeostasis. However, little is known about the molecular mechanisms of endothelial barrier repair following injury. To investigate the functional role of forkhead box M1 (FoxM1) in the mechanism of endothelial repair, we generated endothelial cell-restricted FoxM1-deficient mice (FoxM1 CKO mice). These mutant mice were viable and exhibited no overt phenotype. However, in response to th ...[more]

PMID: 16955137

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Project description:Objective: This investigation examined the effect of velvet antler (VA) on endothelial progenitor cells (EPCs) and the associated effects to promote angiogenesis and repair vascular endothelial injury in rats with myocardial infarction (MI). Methods: VA was analyzed by liquid chromatography-mass spectrometry. Male Sprague Dawley rats were randomly divided into four groups: sham, MI, VA, and VA + DAPT (gamma-secretase inhibitor IX, a specific blocker of the Notch signaling pathway) group. The rats underwent ligation of the left anterior descending coronary artery for the establishment of MI. Sham-operated rats were used as controls. Blood was taken from the orbital plexus on the first and third days after the operation, and all rats were euthanized on the 7th day after surgery. The blood samples were used to detect the contents of circulating endothelial progenitor cells (CEPCs) and vascular endothelial growth factor (VEGF). Echocardiography was used to test the cardiac function. Cardiac tissue was used for immunohistochemistry and electron microscope, and the marginal zone of the MI tissue was used for western blot and reverse transcription-quantitative polymerase chain reaction. Results: The number of basically qualitative metabolites is 445. Among them, there are 74 substances with relative content greater than 0.05%. VA increased the concentration of CEPCs and VEGF in serum, CD133 content and microvessel density (MVD), and protected the morphology of microvascular endothelial cells in the marginal area of MI at 7 days post-MI surgery. CEPCs and MVD in the VA +DAPT group were lower than those of VA group. VA increased the protein expressions of Jagged-1, Notch1, NICD and HES1, and the mRNA expressions of Hes1 and Hey2, while some of the effects could be suppressed by DAPT. Conclusion: These results suggest that VA promotes the mobilization of EPCs to promote angiogenesis and repair vascular endothelial cell damage in post-MI rats, and these effects may be due to activation of the Notch signal pathway.

Project description:BackgroundTraumatic Brain Injury (TBI) is a major cause of disability and mortality, to which there is currently no comprehensive treatment. Blood Brain Barrier (BBB) dysfunction is well documented in human TBI patients, yet the molecular mechanisms that underlie this neurovascular unit (NVU) pathology remains unclear. The apolipoprotein-E (apoE) protein has been implicated in controlling BBB integrity in an isoform dependent manner, via suppression of Cyclophilin A (CypA)-Matrix metallopeptidase-9 (MMP-9) signaling cascades, however the contribution of this pathway in TBI-induced BBB permeability is not fully investigated.MethodsWe exposed C57Bl/6 mice to controlled cortical impact and assessed NVU and BBB permeability responses up to 21 days post-injury. We pharmacologically probed the role of the CypA-MMP-9 pathway in BBB permeability after TBI using Cyclosporin A (CsA, 20 mg/kg). Finally, as the apoE4 protein is known to be functionally deficient compared to the apoE3 protein, we used humanized APOE mice as a clinically relevant model to study the role of apoE on BBB injury and repair after TBI.ResultsIn C57Bl/6 mice there was an inverse relationship between soluble apoE and BBB permeability, such that damaged BBB stabilizes as apoE levels increase in the days following TBI. TBI mice displayed acute pericyte loss, increased MMP-9 production and activity, and reduced tight-junction expression. Treatment with the CypA antagonist CsA in C57Bl/6 mice attenuates MMP-9 responses and enhances BBB repair after injury, demonstrating that MMP-9 plays an important role in the timing of spontaneous BBB repair after TBI. We also show that apoe mRNA is present in both astrocytes and pericytes after TBI. We report that APOE3 and APOE4 mice have similar acute BBB responses to TBI, but APOE3 mice display faster spontaneous BBB repair than APOE4 mice. Isolated microvessel analysis reveals delayed pericyte repopulation, augmented and sustained MMP-9 expression at the NVU, and impaired stabilization of Zonula Occludens-1, Occludin and Claudin-5 expression at tight junctions in APOE4 mice after TBI compared to APOE3 mice.ConclusionsThese data confirm apoE as an important modulator of spontaneous BBB stabilization following TBI, and highlights the APOE4 allele as a risk factor for poor outcome after TBI.

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Endothelial cell-restricted disruption of FoxM1 impairs endothelial repair following LPS-induced vascular injury.

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Endothelial cell-restricted disruption of FoxM1 impairs endothelial repair following LPS-induced vascular injury.

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