Placental profiling of UGT1A enzyme expression and activity and interactions with preeclampsia at term.

Abstract

Placental UDP-glucuronosyltransferase (UGT) enzymes have critical roles in hormone, nutrient, chemical balance and fetal exposure during pregnancy. Placental UGT1A isoforms were profiled and differences between preeclamptic (PE) and non-PE placental UGT expression determined. In third trimester villous placenta, UGT1A1, 1A4, 1A6 and 1A9 were expressed and active in all specimens (n=10), but UGT1A3, 1A5, 1A7, 1A8 and 1A10 were absent. The UGT1A activities were comparable to human liver microsomes per milligram, but placental microsome yields were only 2% of liver (1mg/g of tissue vs. 45mg/g of tissue). For successful PCR, placental collection and processing within60min from delivery, including DNAse and ≥300ng of RNA in reverse transcription were essential and snap freezing in liquid nitrogen immediately was the best preservation method. Although UGT1A6 mRNA was lower in PE (P<0.001), there were no other significant effects on UGT mRNA, protein or activities. A more comprehensive tissue sample set is required for confirmation of PE interactions with UGT. Placental UGT1A enzyme expression patterns are similar to the liver and a detoxicative role for placental UGT1A is inferred.