H19 Is Expressed in Hybrid Hepatocyte Nuclear Factor 4α(+) Periportal Hepatocytes but Not Cytokeratin 19(+) Cholangiocytes in Cholestatic Livers

Long noncoding RNA (lncRNA) H19 is abundantly expressed in fetal liver. Its expression is significantly diminished in adult healthy liver but is re‐induced in chronic liver diseases, including cholestasis. In this study, we developed a new method with combined in situ hybridization (ISH) and immunofluorescence (IF) colabeling to establish an H19 expression profile with both parenchymal and nonparenchymal cell‐specific markers in the livers of cholestatic mouse models and patients with cholestasis. H19RNA(+) cells showed no colocalization with biliary epithelial cell marker cytokeratin 19 (CK19)(+) cholangiocytes but were immediately adjacent to biliary structures in bile duct ligation (BDL), 3,5‐diethoxycarbony1‐1,4‐dihydrocollidine (DDC), and multidrug‐resistant gene 2 knockout (Mdr2(–/–)) mouse models and in human primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) liver specimens. In contrast, double‐positive H19RNA(+)/sex‐determining region Y (SRY)‐box 9 (SOX9)(+) ductal progenitor cells, H19RNA(+)/hepatocyte nuclear factor 4α (HNF4α)(+) hepatocytes, H19RNA(+)/F4/80(+) Kupffer cells, HNF4α(+)/SOX9(+) hybrid hepatocytes, as well as triple‐positive H19RNA(+)/HNF4α(+)/SOX9(+) periportal hepatocytes were identified. In addition, H19RNA could not be detected in mesenchymal cell marker desmin(+) cells. Furthermore, H19RNA was predominately detected in cytoplasm with a small amount at the interspace with neighboring cells. Conclusion: H19RNA is localized in HNF4α(+) periportal hepatocytes, SOX9(+) ductal progenitor cells, and F4/80(+) Kupffer cells but not in CK19(+) cholangiocytes and desmin(+) stellate cells in cholestatic livers.