Project description:The goal of this experiment was to test whether human hepatocytes could give rise to biliary-like progenitor cells in an in vivo context. Here Fah-/- Il2ry-/- Rag2-/-NOD mouse livers were humanized with human hepatocytes. Only hepatocytes engraft in the Fah-/- mouse at detectable levels in this model. Then animals were given chronic liver injury with 0.1% ddc. After injury we measured human-specific transcripts to determine whether the phenotype of the human cells had changed. Specifically, we evaluated the relative levels of human biliary duct markers such as Spp1, Sox9, Krt7, etc. and hepatocyte markers such as Alb, Ttr, Fah, etc. 3 DDC treated chimeras and 6 untreated chimeras are included. Additional controls include a normal human liver biopsy, FACS sorted primary intrahepatic human bile duct cells, mouse hepatocytes, and mouse intrahepatic biliary cells in ddc treated animal.
Project description:The goal of this experiment was to test whether human hepatocytes could give rise to biliary-like progenitor cells in an in vivo context. Here Fah-/- Il2ry-/- Rag2-/-NOD mouse livers were humanized with human hepatocytes. Only hepatocytes engraft in the Fah-/- mouse at detectable levels in this model. Then animals were given chronic liver injury with 0.1% ddc. After injury we measured human-specific transcripts to determine whether the phenotype of the human cells had changed. Specifically, we evaluated the relative levels of human biliary duct markers such as Spp1, Sox9, Krt7, etc. and hepatocyte markers such as Alb, Ttr, Fah, etc.
Project description:The role of PPARα in gene regulation in mouse liver is well characterized. However, less is known about the effect of PPARα activation in human liver. The aim of the present study was to better characterize the impact of PPARα activation on gene regulation in human liver by combining transcriptomics with the use of hepatocyte humanized livers. To that end, chimeric mice containing hepatocyte humanized livers were given an oral dose of 300 mg/kg fenofibrate daily for 4 days. Livers were collected and analysed by hematoxilin and eosin staining, qPCR, and transcriptomics. Transcriptomics data were compared with existing datasets on fenofibrate treatment in normal mice. The human hepatocytes exhibited excessive lipid accumulation. Fenofibrate increased the size of the mouse but not human hepatocytes, and tended to reduce steatosis in the human hepatocytes. Quantitative PCR indicated that induction of PPARα targets by fenofibrate was less pronounced in the human hepatocytes than in the residual mouse hepatocytes. Transcriptomics analysis indicated that, after filtering, a total of 282 genes was significantly different between fenofibrate- and control-treated mice (P<0.01). 123 genes were significantly lower and 159 genes significantly higher in the fenofibrate-treated mice, including many established PPARα targets such as FABP1, HADHB, HADHA, VNN1, PLIN2, ACADVL and HMGCS2. According to gene set enrichment analysis, fenofibrate upregulated interferon/cytokine signaling-related pathways in hepatocyte humanized liver, but downregulated these pathways in normal mouse liver. Also, fenofibrate downregulated pathways related to DNA synthesis in hepatocyte humanized liver but not in normal mouse liver. The results support the major role of PPARα in regulating hepatic lipid metabolism, and underscore the more modest effect of PPARα activation on gene regulation in human liver compared to mouse liver. The data suggest that PPARα may have a suppressive effect on DNA synthesis in human liver, and a stimulatory effect on interferon/cytokine signalling.
Project description:Hepatic drug metabolism plays a key role in determining drug response and safety. Studies of drug metabolism generate valuable information about regulation of genes encoding drug-metabolizing enzymes and enzyme functions that are critical in developing dosing guideline. However, current knowledge is insufficient to support dosing guideline for pregnant women. Specifically, substrates of a major drug-metabolizing enzyme CYP2D6 show increased elimination during pregnancy, but the underlying mechanisms are completely unknown largely due to a lack of experimental models. Here, we introduce CYP2D6-humanized (Tg-CYP2D6) mice as an animal model where hepatic CYP2D6 expression is increased during pregnancy, recapitulating the clinically reported changes in CYP2D6-mediated drug metabolism. In these mice, pregnancy had minimal effects on the expression of hepatocyte nuclear factor (HNF) 4a, the transcription factor controlling basal CYP2D6 expression. Krüppel-like factor (KLF) 9 and small heterodimer partner (SHP) were found up- and down-regulated in Tg-CYP2D6 mouse livers during pregnancy, respectively. KLF9 enhanced HNF4a-mediated transactivation of the CYP2D6 promoter whereas SHP repressed it. Retinoic acid (RA), an endogenous compound that induces SHP, exhibited decreased hepatic levels during pregnancy. These results indicate that interplay among hepatic transcription factors HNF4a, SHP, and KLF9 underlies CYP2D6 induction during pregnancy, and that retinoic acid is a potential trigger. This is the first report on the mechanisms underlying CYP2D6 induction and illustrates the utility of humanized mice as an in vivo model to study altered drug disposition during pregnancy. Livers collected at pre-pregnancy, 21 days of pregnancy, and 7 days postpartum from CYP2D6-humanized mice.
Project description:This study explore the role of the Myc oncogene in liver injury, in particular for the determination of the cellular programme involved in tissue repair and normalization after injury, a process that is blocked by Myc deregulation. The first objective of this study is to define the transcriptional profile of mouse livers 12 days after injury with or without MycER activation. The second objective is to determine the trancriptionl signature at 1,2,3,7 days after MycER was inactivated in pre injured liver to monitor its normalization.