In vivo modulation of the rat cytochrome P450 1A1 by double-stranded phosphorothioate oligodeoxynucleotides.
CYP1A1 gene expression is regulated by known cis- and transacting elements controlling inhibition and induction of CYP1A1 transcription. The influence of a double-stranded phosphorothioate oligonucleotide (dsODN) with sequence identical to the CYP1A1 negative regulatory element (NRE) was examined in Sprague-Dawley rats. Two strategies were employed: (i) two single-stranded complementary 25-mer ODNs that form a double-stranded ODN (ODN1) and (ii) a 54-base, self-complementary ODN which forms a dsODN hairpin (ODN2). A dsODN hairpin with scrambled NRE sequence was evaluated as a control (ODN3). Zoxazolamine paralysis times, an in vivo marker of CYP1A1 activity, were reduced from 184 +/- 18 min in saline-treated rats to 103 +/- 12.5 min 24 hr after a single 1.7-mg ODN1 iv injection. Liver microsomal EROD, an in vitro marker of CYP1A1/2 activity, was increased from 210 +/- 10 pmol in saline-treated animals to 703 +/- 73 and 623 +/- 89 pmol resorufin/mg protein/min after iv ODN1 and iv ODN2, respectively. ODN1's activity did not change PNP hydroxylation and PROD, markers of CYPs 2E1 and 2B1/2. ODN2 did not significantly change PNP but did significantly alter PROD. The ODN3 did not cause any significant changes in any assay measured. The ODN1-induced responses in ZX paralysis and EROD were observed post-iv injection, but not following ip injection of ODN1. Western blot analysis of ODN1- and HPO-treated rat liver microsomes also revealed increased in CYP1A1 protein. These data indicate double-stranded ODNs mimic the cis-acting NRE in vivo inducing CYP1A1 in the absence of other xenobiotics.
Tracewell
W
W
Department of Pharmacology, University of Nebraska Medical Center, Omaha 68198-6260, USA.
Desjardins
J
J
Iversen
P
P
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D010088:Oxidoreductases / Q000378:metabolism; D010243:Paralysis / Q000139:chemically induced; D051381:Rats; D017207:Rats, Sprague-Dawley; D013873:Thionucleotides / Q000494:pharmacology*; D015049:Zoxazolamine / Q000494:pharmacology
D009838:Oligodeoxyribonucleotides; D013873:Thionucleotides; D003577:Cytochrome P-450 Enzyme System; D015049:Zoxazolamine; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1; D019362:Cytochrome P-450 CYP2B1