TRAJECTORY ANALYSIS OF HEPATIC STELLATE CELL DIFFERENTIATION REVEALS METABOLIC REGULATION OF CELL COMMITMENT AND FIBROSIS

Defining the trajectory of cells during differentiation and disease is key for uncovering the mechanisms driving cell fate and identity. However, trajectories of human cells remain largely unexplored due to the challenges of studying them with human samples. In this study, we investigated the proteome trajectory of iPSCs differentiation to hepatic stellate cells (diHSCs) and identified RORA as a key transcription factor governing the metabolic reprogramming of HSCs necessary for HSCs’ commitment, identity, and activation. Using RORA deficient iPSCs and pharmacologic interventions, we showed that RORA is required for early differentiation and prevents diHSCs activation by reducing the high energetic state of the cells. While RORA knockout mice had enhanced fibrosis, whereas RORA agonists rescued multi-organ fibrosis in in vivo models. Notably, RORA expression was consistently found to be negatively correlated with liver fibrosis and HSCs activation markers in patients with liver disease. This study reveals that RORA regulates cell metabolic plasticity, crucial for mesoderm differentiation, pericyte quiescence, and fibrosis, influencing cell commitment and disease.