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Updated: Jul 16, 2026
Human Liver Microphysiological System for Assessing Drug-Induced Liver Toxicity In Vitro
Published on: January 31, 2022
A microarray analysis of the temporal response of liver to methylprednisolone: a comparative analysis of two dosing
Richard R Almon1, Debra C DuBois, William J Jusko
1Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York 14260, USA. almon@eng.buffalo.edu
Abstract:
Microarray analyses were performed on livers from adrenalectomized male Wistar rats chronically infused with methylprednisolone (MPL) (0.3 mg/kg.h) using Alzet mini-osmotic pumps for periods ranging from 6 h to 7 d. Four control and 40 drug-treated animals were killed at 10 different times during drug infusion. Total RNA preparations from the livers of these animals were hybridized to 44 individual Affymetrix REA230A gene chips, generating data for 15,967 different probe sets for each chip. A series of three filters were applied sequentially. These filters were designed to eliminate probe sets that were not expressed in the tissue, were not regulated by the drug, or did not meet defined quality control standards. These filters eliminated 13,978 probe sets (87.5%) leaving a remainder of 1989 probe sets for further consideration. We previously described a similar dataset obtained from animals after administration of a single dose of MPL (50 mg/kg given iv). That study involved 16 time points over a 72-h period. A similar filtering schema applied to the single-bolus-dose dataset identified 1519 probe sets as being regulated by MPL. A comparison of datasets from the two different dosing regimens identified 358 genes that were regulated by MPL in response to both dosing regimens. Regulated genes were grouped into 13 categories, mainly on gene product function. The temporal profiles of these common genes were subjected to detailed scrutiny. Examination of temporal profiles demonstrates that current perspectives on the mechanism of glucocorticoid action cannot entirely explain the temporal profiles of these regulated genes.
Insights
Chronic methylprednisolone (MPL) infusion in rats reveals complex gene regulation patterns. Analysis of temporal gene expression profiles suggests current glucocorticoid action mechanisms are insufficient to explain observed effects.
Area of Science:
- Molecular biology
- Pharmacology
- Endocrinology
Background:
- Glucocorticoids, like methylprednisolone (MPL), are potent anti-inflammatory and immunosuppressive agents.
- Understanding the temporal dynamics of gene expression following MPL administration is crucial for elucidating its mechanisms of action.
Purpose of the Study:
- To investigate the temporal gene expression profiles in rat liver following chronic infusion of methylprednisolone (MPL).
- To compare gene regulation patterns between chronic MPL infusion and a single high-dose MPL administration.
- To identify genes regulated by both dosing regimens and analyze their temporal profiles.
Main Methods:
- Microarray analysis using Affymetrix REA230A gene chips on liver RNA from adrenalectomized Wistar rats.
- Chronic infusion of MPL (0.3 mg/kg/h) via osmotic pumps for up to 7 days.
- Application of stringent filtering criteria to identify regulated probe sets and comparison with a previously generated single-dose dataset.
Main Results:
- Out of 15,967 probe sets, 1989 were identified as regulated by chronic MPL infusion after filtering.
- A previous study identified 1519 probe sets regulated by a single MPL dose.
- A total of 358 genes were found to be regulated by MPL under both chronic and single-dose conditions.
Conclusions:
- The temporal expression profiles of genes commonly regulated by both chronic and single-dose MPL administration present a complex picture.
- Current understanding of glucocorticoid action mechanisms may not fully account for the observed temporal gene expression dynamics.
- Further research is needed to refine models of glucocorticoid signaling and gene regulation.
