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 is unclear. Here, we demonstrated that expression of epithelial splicing regulatory protein-2 (ESRP2), an RNA splicing factor that maintains the non-proliferative, 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 re-emergence 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 threatens overall survival by populating the liver with functionally-immature hepatocytes. Our findings revealed a novel 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.
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