Indiana University-Purdue University Indianapolis (IUPUI) / Developmental changes in the liver significantly impact drug disposition. Due to the
emergence of microRNAs as important regulators of drug disposition, we hypothesize that
age-dependent change in microRNA expression and genetic variants in microRNA target
sites contribute to variability in drug disposition. In human liver tissues, expression of 533
microRNAs and over 14,000 genes were measured. In all, 114 microRNAs were
upregulated and 72 downregulated from fetal to pediatric, and 2 and 3, respectively, from
pediatric to adult. Among these microRNAs, 99 microRNA-mRNA interactions were
predicted or have previously been validated to target drug disposition genes and over
1,000 significant negative correlations were observed between miRNA-mRNA pairs. We
validated these interactions using various cell culture models. Genetic variants in the
promoter and coding regions of drug disposition genes have also been shown to alter
enzyme expression and/or activity. However, these variants do not account for all
variability in enzyme activity. Emerging evidence has shown that variants in the 3’UTR
may explain variable drug response by altering microRNA regulation. Five 3’UTR variants
were associated with significantly altered CYP2B6 activity in healthy human volunteers.
The rs70950385 (AG>CA) variant was associated with decreased CYP2B6 activity among
normal metabolizers. In vitro luciferase assays confirmed that the CA allele altered miR
1275 targeting of CYP2B6 mRNA. Due to the large number of 3’UTR variants predicted
to alter microRNA regulation, a high-throughput method, PASSPORT-seq, was developed
to test over 100 3’UTR variants simultaneously in different cell lines. Thirty-eight variants resulted in FDR-significant altered expression between wild-type and variant sequences.
Our data suggest a mechanism for the marked changes in hepatic gene expression
between the fetal and pediatric developmental periods, support a role for these age
dependent microRNAs in regulating drug disposition, and provide strong evidence that
3’UTR variants are also an important source of variability in drug disposition.
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/14971 |
| Date | 31 August 2017 |
| Creators | Burgess, Kimberly Sherrelle |
| Contributors | Skaar, Todd C., Arrizabalaga, Gustavo, Cummins, Theodore, Desta, Zeruesenay, Nass, Richard, Zhang, Jian-Tian |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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