Liver sinusoidal endothelial cells contribute to portal hypertension through collagen type IV–driven sinusoidal remodeling
Can Gan, Usman Yaqoob, Jianwen Lu, Man Xie, Abid Anwar, Nidhi Jalan-Sakrikar, Sofia Jerez, Tejasav S. Sehrawat, Amaia Navarro-Corcuera, Enis Kostallari, Nawras W. Habash, Sheng Cao, Vijay H. Shah
Can Gan, Usman Yaqoob, Jianwen Lu, Man Xie, Abid Anwar, Nidhi Jalan-Sakrikar, Sofia Jerez, Tejasav S. Sehrawat, Amaia Navarro-Corcuera, Enis Kostallari, Nawras W. Habash, Sheng Cao, Vijay H. Shah
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Research Article Cell biology Hepatology

Liver sinusoidal endothelial cells contribute to portal hypertension through collagen type IV–driven sinusoidal remodeling

Abstract

Portal hypertension (PHTN) is a severe complication of liver cirrhosis and is associated with intrahepatic sinusoidal remodeling induced by sinusoidal resistance and angiogenesis. Collagen type IV (COL4), a major component of basement membrane, forms in liver sinusoids upon chronic liver injury. However, the role, cellular source, and expression regulation of COL4 in liver diseases are unknown. Here, we examined how COL4 is produced and how it regulates sinusoidal remodeling in fibrosis and PHTN. Human cirrhotic liver sample RNA sequencing showed increased COL4 expression, which was further verified via immunofluorescence staining. Single-cell RNA sequencing identified liver sinusoidal endothelial cells (LSECs) as the predominant source of COL4 upregulation in mouse fibrotic liver. In addition, COL4 was upregulated in a TNF-α/NF-κB–dependent manner through an epigenetic mechanism in LSECs in vitro. Indeed, by utilizing a CRISPRi-dCas9-KRAB epigenome-editing approach, epigenetic repression of the enhancer-promoter interaction showed silencing of COL4 gene expression. LSEC-specific COL4 gene mutation or repression in vivo abrogated sinusoidal resistance and angiogenesis, which thereby alleviated sinusoidal remodeling and PHTN. Our findings reveal that LSECs promote sinusoidal remodeling and PHTN during liver fibrosis through COL4 deposition.

Authors

Can Gan, Usman Yaqoob, Jianwen Lu, Man Xie, Abid Anwar, Nidhi Jalan-Sakrikar, Sofia Jerez, Tejasav S. Sehrawat, Amaia Navarro-Corcuera, Enis Kostallari, Nawras W. Habash, Sheng Cao, Vijay H. Shah

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Figure 6

LSEC-specific COL4 promotes sinusoidal resistance.

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LSEC-specific COL4 promotes sinusoidal resistance. (A) After PHTN model ...
(A) After PHTN model establishment, LSECs were isolated for qPCR analysis. Results showed increased expression of Cd34 (capillarization marker) and decreased expression of Lyve1 and Stab1 (LSEC markers) in CCl4-induced LSECs. In contrast, Col4a1 mutation in LSECs maintained the LSEC phenotype, as shown by a decrease in Cd34 and an increase in Lyve1 and Stab1 levels (n = 3/group). Graphs represent mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, 1-way ANOVA followed by Bonferroni’s posttest. (B and C) Healthy LSECs had characteristic fenestrae (red arrows) on transmission electron microscopy (TEM) (B) and a sieve plate (red stars) on scanning electron microscopy (SEM) (C). Bottom images in B are magnifications of red boxes on top images. Scale bars: 500 nm (B top), 200 nm (B bottom), 1 μm (C). In contrast, CCl4 induced the defenestration of LSECs, indicated by the loss of fenestrae and formation of basement membrane (black arrows), as well as other collagens’ deposition in perisinusoidal space (black star). Col4a1 mutation in LSECs restored the LSEC phenotype by maintaining the fenestrae and sieve plate. (n = 2/group for TEM and SEM.)