title: Mathematical modeling of corticosteroid pharmacogenomics in rat muscle following acute and chronic methylprednisolone dosing.
abstract: The pharmacogenomic effects of a corticosteroid (CS) were assessed in rat skeletal muscle using microarrays. Adrenalectomized (ADX) rats were treated with methylprednisolone (MPL) by either 50 mg/kg intravenous injection or 7-day 0.3 mg/kg/h infusion through subcutaneously implanted pumps. RNAs extracted from individual rat muscles were hybridized to Affymetrix Rat Genome Genechips. Data mining yielded 653 and 2316 CS-responsive probe sets following MPL bolus and infusion treatments. Of these, 196 genes were controlled by MPL under both dosing conditions. Cluster analysis revealed that 124 probe sets exhibited three typical expression dynamic profiles following acute dosing. Cluster A consisted of up-regulated probe sets which were grouped into five subclusters each exhibiting unique temporal patterns during the infusion. Cluster B comprised down-regulated probe sets which were divided into two subclusters with distinct dynamics during the infusion. Cluster C probe sets exhibited delayed down-regulation under both bolus and infusion conditions. Among those, 104 probe sets were further grouped into subclusters based on their profiles following chronic MPL dosing. Several mathematical models were proposed and adequately captured the temporal patterns for each subcluster. Multiple types of dosing regimens are needed to resolve common determinants of gene regulation as chronic exposure results in unexpected differences in gene expression compared to acute dosing. Pharmacokinetic/pharmacodynamic (PK/PD) modeling provides a quantitative tool for elucidating the complexities of CS pharmacogenomics in skeletal muscle.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, New York 14260, USA.
authors.forename: Zhenling
authors.initials: Z
authors.lastname: Yao
authors.forename: Eric P
authors.initials: EP
authors.lastname: Hoffman
authors.forename: Svetlana
authors.initials: S
authors.lastname: Ghimbovschi
authors.forename: Debra C
authors.initials: DC
authors.lastname: Dubois
authors.forename: Richard R
authors.initials: RR
authors.lastname: Almon
authors.forename: William J
authors.initials: WJ
authors.lastname: Jusko
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D008962:Models, Theoretical; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010597:Pharmacogenetics; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008775:Methylprednisolone