ETS1 suppresses hepatic stellate cell activation and liver fibrosis
Wonseok Lee, Xiao Liu, Sara Brin Rosenthal, Charlene Miciano, Sadatsugu Sakane, Kanani Hokutan, Debanjan Dhar, Hyun Young Kim, David A. Brenner, Tatiana Kisseleva
Wonseok Lee, Xiao Liu, Sara Brin Rosenthal, Charlene Miciano, Sadatsugu Sakane, Kanani Hokutan, Debanjan Dhar, Hyun Young Kim, David A. Brenner, Tatiana Kisseleva
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Research Article Cell biology Gastroenterology Hepatology

ETS1 suppresses hepatic stellate cell activation and liver fibrosis

Abstract

Chronic liver injury results in activation of quiescent hepatic stellate cells (HSCs) into collagen type I–producing activated HSCs that make the liver fibrotic. We identified ETS1 and ETS2 (ETS1/2) as lineage-specific transcription factors regulating HSC phenotypes. Here, we investigated the role of ETS1/2 in HSCs in liver fibrosis using toxic liver injury models and 3D human liver spheroids. Liver fibrosis was induced in WT and HSC-specific Ets1-KO (Ets1ΔHSC) and Ets2-KO (Ets2ΔHSC) mice by administration of CCl4 for 6 weeks, followed by cessation of liver injury for 2 weeks. Liver fibrosis was more severe in Ets1ΔHSC and to a lesser extent Ets2ΔHSC mice compared with WT mice. Regression of liver fibrosis was suppressed only in Ets1ΔHSC mice, indicating Ets1 is the predominant isoform maintaining a quiescent-like phenotype in HSCs. Similar results were obtained in a metabolic dysfunction–associated steatohepatitis (MASH) model using 3D human liver spheroids. Knockdown of ETS1 in human HSCs caused upregulation of fibrogenic genes in MASH human liver spheroids and prevented fibrosis regression. ETS1 regulated the quiescent HSC phenotype via the CREB-regulated transcription coactivator 2 (CRTC2)/PGC1α/PPARγ pathway. Knockdown of CRTC2 abrogated PPARγ responses and facilitated HSC activation. These findings suggest that ETS1 may represent a therapeutic target for antifibrotic therapy.

Authors

Wonseok Lee, Xiao Liu, Sara Brin Rosenthal, Charlene Miciano, Sadatsugu Sakane, Kanani Hokutan, Debanjan Dhar, Hyun Young Kim, David A. Brenner, Tatiana Kisseleva

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Figure 7

ETS1 regulates PPARγ via the CRTC2 pathway in human HSCs.

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ETS1 regulates PPARγ via the CRTC2 pathway in human HSCs. (A) Schematic ...
(A) Schematic illustration of dsiRNA transfection and rosiglitazone treatment. Human HSCs were transfected with dsiRNA for 48 hours and treated with recombinant human TGF-β1 protein (5 ng/mL) with or without rosiglitazone (20 μM or vehicle) for 24 hours. (B) The expression of fibrogenic genes was measured in ETS1-targeting dsiRNA-transfected HSCs after rosiglitazone treatment by qRT-PCR. (C) ETS1 direct target genes were overlapping with the genes downregulated in ETS1 knockdown HSCs (vs. HSCs infected with nontargeting shRNA) in our RNA-Seq dataset. ETS1 target genes were identified from the ENCODE and ChEA databases. (D) ETS1 locus-specific ChIP-qPCR analysis was performed using human HSCs. (E and F) Human HSCs were transfected with ETS1-targeting dsiRNA or dsiNC (dsi-negative control). (E) CRTC2 and (F) CRTC2 downstream genes were measured using Western blot analysis or qRT-PCR. (G) Human HSCs were transfected with 3 different CRTC2-targeting dsiRNA or dsiNC (dsi-negative control) for 48 hours, and the efficiency of gene knockdown was measured by qRT-PCR. (H) mRNA expression of PPARGC1A and PPARG in CRTC2-targeting dsiRNA-transfected HSCs. (I) mRNA expression of fibrogenic markers was measured in dsiCRTC2-transfected HSCs. (J) Schematic illustration of the underlying mechanism by which ETS1 regulates the HSC phenotype through CRTC2. Data are expressed as the mean ± SD; *P < 0.05, **P < 0.01, and ***P < 0.001, 1-way ANOVA followed by Tukey’s test.