After DAPM repeated administration ~20% of the bile ducts turned DPPIV-positive indicating that they are derived from DPPIV positive hepatocytes (Figure 2C). Figure 2 Appearance of DPPIV in bile ducts cells

after repeated DAPM administration (DAPM × 3).(A) Schematic representation of repeated DAPM administration protocol. DAPM (50 mg/kg) administered at day 0, 2, and 4 to the DPPIV chimeric rats. Rats sacrificed at day 30 after the last DAPM injection. DPPIV staining before #BI 2536 ic50 randurls[1|1|,|CHEM1|]# (B) and after (C) repeated DAPM administration to the DPPIV chimeric rats. Arrowheads point to the DPPIV positive bile ducts. Arrows indicate DPPIV negative bile ducts. The number of DPPIV positive bile ducts was determined after counting DPPIV positive bile ductules in liver sections obtained from different lobes EX 527 of liver from 3 individual rats separately. None of the bile duct cells of the DPPIV chimeric rats were positive before DAPM treatment. ~20% bile ducts were noted to be

DPPIV positive after DAPM × 3 protocol. Scale bar = 100 μm. Periportal hepatocyte expression of CK19 CK19 was expressed only in BEC in the normal liver (Figure 3A). However, after DAPM treatment protocol, selective periportal hepatocytes were also strongly positive for CK19 in addition to the BEC (Figure 3B and 3C). Periportal hepatocytic CK19 staining was not uniform across the liver lobule. These findings indicate that the periportal hepatocytes only in the proximity of the affected biliary cells offer a pool of facultative stem cells capable of transdifferentiation to biliary cells. Figure 3 Localization of CK19 following DAPM + BDL or repeated DAPM treatment (DAPM × 3). (A) Normal rat liver (NRL), (B) liver from DAPM + BDL treated rat, (C) liver from repeated DAPM treatment (DAPM x3). Brown color indicates CK19 positive staining. Arrows indicate bile duct staining. Arrowheads indicate hepatocytic staining. PV, portal vein; BD, bile duct. Scale bar = 100 μm. Hepatocyte-associated transcription factor HNF4 α expression in newly formed biliary ductules Figure 4 depicts the HNF4α (Figure 4A, B, and 4C) and CK19 (Figure 4D, E, and 4F) stainings

on the serial Interleukin-2 receptor liver sections. In the normal rat liver, nuclear HNF4α expression is observed only in the hepatocytes (Figure 4A). However, the biliary ductules undergoing repair after repeated DAPM administration or DAPM + BDL show incorporation of cells resembling hepatocyte morphology that also had HNF4α positive staining (Figure 4B and 4C, respectively). In Figure 4C and 4F there is a panel of ductules in which only some of the cells in a duct are HNF4α positive and only some of the cells are CK19 positive (with overlap between some of the cells). Figure 4 HNF4α and CK19 immunohistochemistry. Liver sections obtained from normal control rats (NRL, normal rat liver) (A and D), rats that underwent DAPM + BDL treatment (B and E), or repeated DAPM treatment (DAPM × 3) (C and F). B, E and C, F are serial sections.