title: 3,3',5'-triiodo-L-thyronine reduces efficiency of mRNA knockdown by antisense oligodeoxynucleotides: a study with pyroglutamyl aminopeptidase II in adenohypophysis.
abstract: The impact of hormones on the efficacy of antisense oligodeoxynucleotides (ASOs) is a poorly analyzed subject. We designed, based on the identification of potentially favorable local elements of mRNA secondary structure, eight phosphorothioate ASOs to knock down the expression of an ectopeptidase, pyroglutamyl aminopeptidase II (PPII), in primary cultures of adenohypophysis. Two of the PPII ASOs were very efficient, sequence-specific, and target-specific. Because the expression of PPII is upregulated by 3,3',5'-triiodo-L-thyronine (T3), we studied the impact of varying the protocol of PPII induction on the knockdown efficacy. Hormone removal at transfection increased markedly the ability of (1) PPII ASOs to reduce PPII mRNA levels or PPII activity in adenohypophyseal cells or in C6 rat glioma cells and (2) a thyrotropin-releasing hormone (TRH) receptor-1 (TRH-R1) ASO to reduce TRH-R1 mRNA levels in adenohypophyseal cells. There was no effect of hormone removal on transfection efficacy and no correlation between target mRNA levels and ASO efficacy. These data demonstrated that ASO efficacy could depend on T3 levels; this might be due to regulation of a step generally critical for ASO efficiency.
authors.affiliation: Departamento de Genetica del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mor., México.
authors.forename: Raymundo
authors.initials: R
authors.lastname: Cruz
authors.forename: Lucia
authors.initials: L
authors.lastname: Chávez-Gutiérrez
authors.forename: Patricia
authors.initials: P
authors.lastname: Joseph-Bravo
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Charli
mesh_terms: D000626:Aminopeptidases / Q000235:genetics*; D000818:Animals; D002478:Cells, Cultured; D015536:Down-Regulation; D005260:Female; D016376:Oligonucleotides, Antisense / Q000037:antagonists & inhibitors* / Q000235:genetics; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000201:enzymology; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018025:Receptors, Thyrotropin-Releasing Hormone / Q000235:genetics / Q000378:metabolism; D014285:Triiodothyronine, Reverse / Q000494:pharmacology*
chemical_list: D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D018025:Receptors, Thyrotropin-Releasing Hormone; D014285:Triiodothyronine, Reverse; D000626:Aminopeptidases; C023166:pyroglutamyl-peptidase II; D011761:Pyrrolidonecarboxylic Acid