Lack of PCK1 in hepatic stellate cells causes liver fibrosis by fueling tricarboxylic acid cycle and increasing glycolysis

Phosphoenolpyruvate carboxykinase 1 (PCK1) is a key integrator of hepatic energy metabolism, but its role in hepatic stellate cells (HSCs), the main fibrogenic cells in the liver, remains unknown. We found that PCK1 is reduced in HSCs from fibrotic animals and people with fibrosis, correlating negatively with fibrosis severity. Silencing PCK1 activates human HSCs and increases fibrotic markers, whereas ectopic PCK1 expression blunts transforming growth factor β1 (TGF-β1)-induced activation. Activated HSCs show elevated glycolysis and tricarboxylic acid (TCA) cycle activity, but PCK1 overexpression reduces acetyl-coenzyme A (CoA), limiting TCA cycle intermediates and ameliorating HSC activation. In mice, HSC-specific PCK1 loss accelerates diet-induced liver fibrosis. Notably, mice lacking PCK1 in HSCs also develop spontaneous fibrosis on a normal diet. These findings show that disrupted cataplerosis from PCK1 loss enhances glycolysis and activates HSCs, promoting liver fibrosis.