Alcohol Liver Disease Traps Cells in

Alcohol-related liver disease may trap damaged liver cells in a regenerative limbo, preventing the organ from rebuilding itself even after drinking stops. Researchers at the University of Illinois Urbana-Champaign, Duke University, and the Chan Zuckerberg Biohub Chicago linked the problem to inflammation-driven RNA errors and identified a pathway that could potentially be targeted to restore liver repair.

Alcohol-associated liver disease is the leading cause of liver-related mortality worldwide, linked to roughly 3 million deaths each year. The liver's unique ability to regenerate fails in this condition, and the only life-saving treatment once a patient reaches liver failure is transplantation.

Why the Liver Stops Repairing Itself

The liver can regenerate after significant damage. Surviving cells temporarily change identity, multiply, and then mature again to restore lost tissue. This ability breaks down in alcohol-associated liver disease.

Professor Auinash Kalsotra of the University of Illinois, who co-led the study with Duke University's Professor Anna Mae Diehl, explained the core mystery. Their previous work showed regenerating liver cells temporarily reprogram which genes they use, reverting to a fetal-like progenitor state before maturing again.

Liver Cells Become Trapped in Limbo

The research team compared healthy liver samples with tissue from people with alcohol-associated hepatitis or cirrhosis. A striking pattern emerged. Cells in the diseased livers had started moving toward the regenerative state but were unable to finish the transition. They remained trapped between a mature state and a progenitor state.

U. of I. graduate students Ullas Chembazhi and Sushant Bangru, the study's co-first authors, described the consequence. This creates a damaging cycle where remaining healthy cells face greater demands and attempt to regenerate, only to risk becoming trapped themselves.

RNA Splicing Emerges as a Key Problem

To understand what was preventing cells from completing regeneration, the team examined proteins and RNA molecules inside liver cells. They used deep RNA sequencing and computational analysis to examine RNA splicing, a process where RNA pieces are cut and joined together to produce functional proteins.

In comparing the samples, the researchers saw RNA was getting misspliced broadly in alcohol-related liver disease, across thousands of genes, and it was affecting major functions of proteins. The mis-splicing was substantial, potentially altering how important proteins function throughout damaged liver cells.

A Missing Protein and a Potential Target

The researchers identified low levels of a protein called ESRP2 as a possible driver of these widespread errors. ESRP2 binds to RNA and helps ensure it is spliced correctly. In alcohol-damaged liver cells, ESRP2 was deficient. This deficiency often altered instructions that tell proteins where inside the cell they need to go, causing key proteins for regeneration to get stuck in the cytoplasm instead of reaching the nucleus.

Mouse experiments strengthened the link. Mice lacking the gene for ESRP2 developed patterns of liver injury and failed regeneration resembling advanced alcohol-related hepatitis in humans. The team traced the reduction of ESRP2 back to inflammation. When alcohol damages the liver, immune and support cells release inflammatory factors that suppress both the production and activity of ESRP2.

In laboratory cultures, the researchers used a molecule to block the receptor for one inflammation-promoting factor. After treatment, ESRP2 levels recovered, and RNA splicing became more normal. This result suggests the inflammatory pathway could become a potential treatment target. Future therapies might try to interrupt these signals to allow cells to complete regeneration. The researchers also see potential diagnostic uses, where abnormally spliced RNA molecules could serve as biological markers for the disease.