Epithelial splicing regulatory protein 2–mediated alternative splicing reprograms hepatocytes in severe alcoholic hepatitis
Jeongeun Hyun, … , Auinash Kalsotra, Anna Mae Diehl
Jeongeun Hyun, … , Auinash Kalsotra, Anna Mae Diehl
Published January 16, 2020
Citation Information: J Clin Invest. 2020;130(4):2129-2145. https://doi.org/10.1172/JCI132691.
View: Text | PDF
Research Article Cell biology Hepatology

Epithelial splicing regulatory protein 2–mediated alternative splicing reprograms hepatocytes in severe alcoholic hepatitis

Abstract

Severe alcoholic hepatitis (SAH) is a deadly liver disease without an effective medical therapy. Although SAH mortality is known to correlate with hepatic accumulation of immature liver cells, why this occurs and how it causes death are unclear. Here, we demonstrate that expression of epithelial splicing regulatory protein 2 (ESRP2), an RNA-splicing factor that maintains the nonproliferative, mature phenotype of adult hepatocytes, was suppressed in both human SAH and various mouse models of SAH in parallel with the severity of alcohol consumption and liver damage. Inflammatory cytokines released by excessive alcohol ingestion reprogrammed adult hepatocytes into proliferative, fetal-like cells by suppressing ESRP2. Sustained loss of ESRP2 permitted reemergence of a fetal RNA-splicing program that attenuates the Hippo signaling pathway and thus allows fetal transcriptional regulators to accumulate in adult liver. We further showed that depleting ESRP2 in mice exacerbated alcohol-induced steatohepatitis, enabling surviving hepatocytes to shed adult hepatocyte functions and become more regenerative, but threatening overall survival by populating the liver with functionally immature hepatocytes. Our findings revealed a mechanism that explains why liver failure develops in patients with the clinical syndrome of SAH, suggesting that recovery from SAH might be improved by limiting adult-to-fetal reprogramming in hepatocytes.

Authors

Jeongeun Hyun, Zhaoli Sun, Ali Reza Ahmadi, Sushant Bangru, Ullas V. Chembazhi, Kuo Du, Tianyi Chen, Hidekazu Tsukamoto, Ivan Rusyn, Auinash Kalsotra, Anna Mae Diehl

×

Figure 2

ESRP2 expression and ESRP2-mediated adult RNA-splicing program are downregulated in livers of patients with SAH.

Options: View larger image (or click on image) Download as PowerPoint
ESRP2 expression and ESRP2-mediated adult RNA-splicing program are downr...
(A) The log2 fold changes of ESRP2 and direct YAP/TAZ target genes (CYR61, CTGF, PTGS2) assessed by RNA-Seq in liver explants from SAH patients relative to healthy controls (n = 5 each). (B) Quantitative reverse transcription PCR (qRT-PCR) analysis for ESRP2 and YAP/TAZ target genes (AREG, CYR61, CTGF, PTGS2) in human SAH livers and healthy controls. (C) Immunoblots for ESRP2 normalized to GAPDH as a loading control in lysates of liver tissues from SAH patients and healthy controls. (D) IHC for ESRP2 in explanted liver tissues of SAH patients and healthy human liver. (E) Alternative splicing of ESRP2 target mRNAs including CSNK1D, NF2, SLK, and FLNB between liver tissues of SAH patients and healthy controls. Upper bands include the exon (red part), while the lower bands skip the exon. Exon lengths are shown beside the gene name, and the differences in PSI values are shown as mean ± SEM below each image. (F–H) qRT-PCR analysis (F), immunoblot (G), and IHC (H) for IGF2BP3 in the livers of SAH patients and healthy controls. qRT-PCR results are graphed as dot plots (SAH, black squares; healthy controls, white circles) showing mean ± SEM (red bars) (n = 5 individuals/group). See full, unedited blots for C and G and full, unedited gels for E in the supplemental material. Statistical analysis was performed by using 2-tailed Student’s t test between 2 groups (n = 5 individuals/group, P values are specified otherwise, **P < 0.001). Representative images are shown for IHC. Scale bars: 100 μm (original magnification, ×100), 20 μm (original magnification, ×400).