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 3

NGBR deficiency decreases CCM1/2 expression, increases endothelial permeability, and promotes RhoA/phos-MLC signaling.

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NGBR deficiency decreases CCM1/2 expression, increases endothelial perm...
(A–C) CCM1 and CCM2 mRNA levels decreased in both MBMVECs and HBMVECs due to NGBR deficiency. (A and B) ECs extracted from postnatal and adult-stage mouse brains (MBMVECs) after tamoxifen injection. (C) NGBR in HBMVECs was knocked down with siRNA. mRNA levels were determined by RT-qPCR. siCtrl, control siRNA–treated group; siNGBR, NGBR siRNA–treated group. (D and E) Western blot and quantification results showing that CCM1 and CCM2 protein levels decrease in NGBR-deficient HBMVECs. (F) NGBR deficiency results in an increase in endothelial permeability as determined by EC-monolayer permeability assay. (G) Immunofluorescent staining showing increased phos-MLC in NGBR-deficient HBMVECs. Scale bars: 10 μm. (H and I) Western blot and quantification results showing RhoA and phos-MLC increases in NGBR-knockdown HBMVECs. (J) Immunofluorescent staining showing the impaired AJs (VE-cadherin) and TJs (ZO-1) in NGBR-deficient HBMVECs. Scale bars: 10 μm. Data are presented as mean ± SD, n = 6 mice per group (A and B) and n = 3 samples per group (C, E, F, and I). **P < 0.01, ***P < 0.001. Significance was tested by 2-tailed, unpaired Student’s t test (A–C, E, F, and I).