The purpose of this proposal is to exploit the potential for gene-specific activities of synthetic oligonucleotides (ODNs) in an animal model involving drug metabolism. The mechanistic actions of nuclease resistant ODNs include sequence-specific interactions with nucleic acids as antigene or antisense molecules or with transcriptional regulatory proteins in a manner that mimics the genomic cis-elements resulting in the modulation of gene expression. The investigators intend to test the hypothesis that optimal oligonucleotide structures can be identified that modulate the expression of cytochrome P450 isoforms in vivo. Further, that gene expression modulation will provide insights into the regulation of these genes' expression and their reliance on endogenous substrates and extrahepatic expression. In vivo studies are proposed because ODN entry into and distribution within the cell is not equivalent between studies conducted in cultured cells and that observed in intact animals.
The specific aims of these studies are to: 1) identify optimal oligonucleotide structures for antisense, antigene, ribozyme and transcriptional regulation of gene expression in vivo, 2) evaluate the mechanism of action of these modulators of gene expression, 3) identify in in vivo modulators a broad spectrum of phase I drug metabolizing enzymes including rat CYP1A1, CYP2B1, CYP2B2, CYP2C11, CYP2E1, CYP3A2 and CYP4A1 and 4) evaluate these gene expression modulators in context dependent expression created by sex hormones, circadian rhythm, xenobiotic exposure and extrahepatic organs. The advantages of this model system are that 1) constitutive gene expression is monitored in the absence of disease, 2) the in vivo efficacy is confirmed by in vitro analysis of enzyme activities and protein levels directly link the target mRNA with observed phenotype, 3) toxicity can be evaluated concomitantly with efficacy, 4) the approach is cost effective, 5) this approach avoids discrepancies that are in cell culture and 6) direct comparison of potency, efficacy and toxicity can be made with linear phosphorothioate ODNs. Future studies will involve a more detailed investigation of the role of cytochrome P450 expression in the regulation of radical oxygen sensitive genes in vivo.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM054871-03
Application #
2865274
Study Section
Pharmacology A Study Section (PHRA)
Project Start
1997-06-01
Project End
2001-05-31
Budget Start
1999-06-01
Budget End
2000-05-31
Support Year
3
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Oregon State University
Department
Type
Schools of Veterinary Medicine
DUNS #
053599908
City
Corvallis
State
OR
Country
United States
Zip Code
97339