NOGOB receptor deficiency increases cerebrovascular permeability and hemorrhage via impairing histone acetylation–mediated CCM1/2 expression
Zhi Fang, … , Wenquan Hu, Qing Robert Miao
Zhi Fang, … , Wenquan Hu, Qing Robert Miao
Published March 22, 2022
Citation Information: J Clin Invest. 2022;132(9):e151382. https://doi.org/10.1172/JCI151382.
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Research Article Angiogenesis Vascular biology

NOGOB receptor deficiency increases cerebrovascular permeability and hemorrhage via impairing histone acetylation–mediated CCM1/2 expression

Abstract

The loss function of cerebral cavernous malformation (CCM) genes leads to most CCM lesions characterized by enlarged leaking vascular lesions in the brain. Although we previously showed that NOGOB receptor (NGBR) knockout in endothelial cells (ECs) results in cerebrovascular lesions in the mouse embryo, the molecular mechanism by which NGBR regulates CCM1/2 expression has not been elucidated. Here, we show that genetic depletion of Ngbr in ECs at both postnatal and adult stages results in CCM1/2 expression deficiency and cerebrovascular lesions such as enlarged vessels, blood-brain-barrier hyperpermeability, and cerebral hemorrhage. To reveal the molecular mechanism, we used RNA-sequencing analysis to examine changes in the transcriptome. Surprisingly, we found that the acetyltransferase HBO1 and histone acetylation were downregulated in NGBR-deficient ECs. The mechanistic studies elucidated that NGBR is required for maintaining the expression of CCM1/2 in ECs via HBO1-mediated histone acetylation. ChIP-qPCR data further demonstrated that loss of NGBR impairs the binding of HBO1 and acetylated histone H4K5 and H4K12 on the promotor of the CCM1 and CCM2 genes. Our findings on epigenetic regulation of CCM1 and CCM2 that is modulated by NGBR and HBO1-mediated histone H4 acetylation provide a perspective on the pathogenesis of sporadic CCMs.

Authors

Zhi Fang, Xiaoran Sun, Xiang Wang, Ji Ma, Thomas Palaia, Ujala Rana, Benjamin Miao, Louis Ragolia, Wenquan Hu, Qing Robert Miao

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Figure 8

HBO1 overexpression in vivo ameliorates Ngbr deficiency–promoted cerebral hemorrhage and BBB leakage.

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HBO1 overexpression in vivo ameliorates Ngbr deficiency–promoted cerebra...
HBO1 overexpression in brain ECs of NgbrECKO mice was achieved by the intravenous administration of AAV-BR1-GFP-HBO1 (AAV-HBO1). AAV-BR1-GFP was used as a control. (A) Tamoxifen was injected 1 week after AAV injection, and mice were euthanized 3 weeks after tamoxifen injection as shown in the protocol schematic. (B) Efficacy and localization of AAV-BR1 were determined by immunofluorescent staining of GFP. The images of GFP staining in brain sections showed HBO1-GFP expression in brain ECs (labeled by CD31, red) after tail vein injection of AAV-HBO1. Scale bars: 25 μm. (C) Representative whole-brain images and H&E staining showing hemorrhage sites in AAV-ctrl–injected NgbrECKO mice, while no obvious hemorrhage sites were observed in AAV-HBO1–injected NgbrECKO mice. Scale bars: 100 μm. (D and E) HBO1 overexpression significantly diminished the hyperpermeability in the brains of NgbrECKO mice. Permeability was determined by the quantification of Evans blue extravasation and brain water content. (F) The results of IgG staining showing that AAV-HBO1 injection reduced the IgG-positive staining in the brains of NgbrECKO mice compared with AAV-ctrl–injected NgbrECKO mice. Scale bars: 200 μm. (G) Ccm1/2 mRNA expression was determined in MBMVECs extracted from mice. HBO1 overexpression in vivo rescued Ccm1 and Ccm2 transcription in NgbrECKO MBMVECs. Data are presented as mean ± SD, n = 3 mice per group. Significance was tested by 1-way ANOVA with Dunnett’s post hoc test (D, E, and G). *P < 0.05, **P < 0.01, ***P < 0.001 versus Ngbrfl/fl mice treated with AAV-ctrl; #P < 0.05, ##P < 0.01, ###P < 0.001 versus NgbrECKO mice treated with AAV-ctrl.