GAS6 and Hepatic fibrosis: In addition, Gas6, whose function in fibrotic diseases such as lung and liver fibrosis had been well characterized, was enriched in Mesen I cluster (Figure 2D).30,31 The enriched GO term ECM organization and collagen fibril organization further suggested the role of Mesen I cells in structural organization of adventitia (Figure V in the online-only Data Supplement).