TRAP-seq identifies cystine/glutamate antiporter as a driver of recovery from liver injury

Understanding the molecular basis of the regenerative response following hepatic injury holds promise for improved treatment of liver diseases. Here, we report an innovative method to profile gene expression specifically in the hepatocytes that regenerate the liver following toxic injury. We used the Fah(-/-) mouse, a model of hereditary tyrosinemia, which conditionally undergoes severe liver injury unless fumarylacetoacetate hydrolase (FAH) expression is reconstituted ectopically. We used translating ribosome affinity purification followed by high-throughput RNA sequencing (TRAP-seq) to isolate mRNAs specific to repopulating hepatocytes. We uncovered upstream regulators and important signaling pathways that are highly enriched in genes changed in regenerating hepatocytes. Specifically, we found that glutathione metabolism, particularly the gene Slc7 alpha 11 encoding the cystine/glutamate antiporter (xCT), is massively upregulated during liver regeneration. Furthermore, we show that Slc7 alpha 11 overexpression in hepatocytes enhances, and its suppression inhibits, repopulation following toxic injury. TRAP-seq allows cell type-specific expression profiling in repopulating hepatocytes and identified xCT, a factor that supports antioxidant responses during liver regeneration. xCT has potential as a therapeutic target for enhancing liver regeneration in response to liver injury.