Characteristics of microsomal phase II metabolic enzymes in mouse embryonic stem cell-derived liver tissue / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the characteristics of phase II metabolic enzymes in mouse embryonic stem (ES) cell-derived liver tissue.</p><p><b>METHODS</b>Mature hepatocytes were differentiated from embryonic stem cells in cultured mouse embryoid bodies (EB) at d18. Western blot was used to detect the expression of uridine 5'-diphosphate glucronosyl transferase (UGT1a1,UGT1a6) and microsomal glutathione S-transferases 1(mGST1) during the differentiation course.The derived liver tissue was incubated with UDPGA and 7-HFC,the formation of 7-HFC glucuronide was detected by HPLC to examine the total activities of UGT1a1 and UGT1a6. Furthermore, the microsomes were incubated with CDNB and GSH,and the mGST1 activity was measured by spectrometry.</p><p><b>RESULTS</b>An increase tendency of UGT1a1 expression was noticed during the differentiation course. UGT1a6 and mGST1 were not detected in the earlier stage until d18 of differentiation. The metabolic activity of mGST1 in the derived hepatocytes was 7.65 nmol/min/mg on d18.</p><p><b>CONCLUSION</b>The ES cell-derived liver tissue possesses partial metabolic function of phase II enzymes on d18 of differentiation,which might be used as a model for in vitro research on hepatic pathophysiology and phase II drug metabolism.</p>

Gene expressions of phase II enzymes in mouse embryonic stem cell-derived hepatocytes / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To elucidate gene expressions of phase II enzymes in the mouse embryonic stem (ES) cell-derived hepatocytes.</p><p><b>METHODS</b>Embryoid body (EB) formation cultures were applied in directed differentiation of ES to hepatic-like cells. The expressions of hepatic-specific genes, including AFP, ALB, Cyp7a1, were detected by RT-PCR during the differentiation course. Albumin was detected by immunocyto- chemistry. The gene expressions of mGST1 and UGTs family, including UGT1a1, UGT1a6, UGT1a9 and UGT2b5, were investigated using RT-PCR.</p><p><b>RESULTS</b>A notable gene expression of AFP and ALB was observed on d 8. On d 18, AFP gene failed to express, while ALB and Cyp7a1 genes were detected.Albumin-positive staining was detected in hepatic-like cells. Phase II enzyme genes expressed in variance during the differentiation course, UGT1a1 and UGT1a9 were expressed stably, UGT1a6 expression increased gradually, and UGT2b5 failed to express. Little mGST1 gene expression could been detected in the early course until d 18. In addition, all the enzymes gene expressions in the derived hepatocytes on d 18 were similar to those from mature mouse hepatocytes.</p><p><b>CONCLUSIONS</b>Mouse ES cell-derived mature hepatocytes express phase II enzyme UGTs and mGST1 genes similar to those in mature hepatocytes. The system may offer an alternative animal testing model related to phase enzymes in further research.</p>