Related Experiment Video

Updated: Aug 19, 2026

Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists

Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists

Published on: November 16, 2013

Inhibition of PPAR alpha/RXR alpha-mediated direct hyperplasia pathways during griseofulvin-induced

Y Nagao¹, B A French, Y Cai

¹Department of Pathology, Harbor-UCLA Medical Center, Torrance, California 90509, USA.

Journal of Cellular Biochemistry

|April 21, 1998

Abstract:

Chronic griseofulvin (GF) feeding induces preneoplastic foci followed by hepatocellular carcinoma in the mouse liver. Our previous study suggested that GF-induced hepatocellular proliferation had a different mechanism from that of peroxisome proliferator (PP)-induced direct hyperplasia. The GF-induced hepatocellular proliferation was mediated through activation of immediate early genes such as Fos, Jun, Myc, and NFKB. In contrast, PP-induced direct hyperplasia does not involve activation of any of these immediate early genes. It has been shown that nuclear hormone receptors including peroxisome proliferator activated receptors (PPARs) and retinoid x receptors (RXRs) play important roles in mediating the pleiotropic effects of PPs. To examine the possible roles of PPARs and RXRs during non-PP-induced hepatocellular proliferation and the interaction between PP and non-PP-induced proliferation, we have studied the expression of the PPAR and RXR genes in the GF model using northern blot hybridizations and gel retardation assays. The data showed that the expression of PPARalpha and RXRalpha genes was down-regulated in the livers containing preneoplastic nodules and in the liver tumors induced by GF. The mRNA down-regulation was accompanied by a decrease in the amount of nuclear protein-bound to peroxisome proliferator and retinoic acid responsive elements. Down-regulation was also associated with the suppressed expression of the PPARalpha/RXRalpha target genes (i.e., acyl-Co oxidase and cytochrome P450 4A1) and the catalase gene. The RXR-gamma gene was also down-regulated, but the RARalpha, beta, and gamma and PPARbeta and gamma genes were up-regulated. These results indicated that the hepatocarcinogenesis induced by GF is accompanied by suppression of the PPARalpha/RXRalpha-mediated direct hyperplasia pathway. The differential expression of these nuclear hormone receptors reveals a new aspect for understanding the individual roles and intercommunication of PPAR, RXR, and RAR isoforms in the liver.

More Related Videos

Network Pharmacology Prediction and Experimental Validation of Trichosanthes-Fritillaria thunbergii Action Mechanism Against Lung Adenocarcinoma

Network Pharmacology Prediction and Experimental Validation of Trichosanthes-Fritillaria thunbergii Action Mechanism Against Lung Adenocarcinoma

Published on: March 3, 2023

Mechanism of Kemeng Fang's Inhibition of Podocyte Apoptosis in Rats with Membranous Nephropathy through the PI3K/AKT Signaling Pathway

Mechanism of Kemeng Fang's Inhibition of Podocyte Apoptosis in Rats with Membranous Nephropathy through the PI3K/AKT Signaling Pathway

Published on: August 23, 2024

Related Concept Videos

Interactions Between Signaling Pathways

Interactions Between Signaling Pathways

Signaling cascades usually lack linearity. Multiple pathways interact and regulate one another, allowing cells to integrate and respond to diverse environmental stimuli.
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...

GPCR Desensitization

GPCR Desensitization

G protein-coupled receptor (GPCR) signaling plays a crucial role in cell functioning. GPCR desensitization is an equally essential process. It allows cells to respond to changing environments and regain sensitivity to new stimuli while preventing unnecessary stimulation when no longer needed. Prolonged exposure to stimuli leads to GPCR desensitization. It involves blocking the receptors from binding and activating additional G proteins. This inhibits activation of downstream effectors, thereby...

Teratogenicity

Teratogenicity

The ability of a drug to produce structural deformations and functional abnormalities in the developing embryo or the fetus is called teratogenicity, and the drug producing this effect is known as a teratogen. Teratogenic effects include stillbirth, miscarriage, intrauterine growth restriction, and neurocognitive delay. A teratogen may affect the embryo at different stages of development, which is important in determining the type and extent of the damage. During blastocyst formation, the early...

Mutagenicity and Carcinogenicity

Mutagenicity and Carcinogenicity

Mutagenicity and carcinogenicity refer to the ability of drugs to cause genetic defects and induce cancer, respectively. The International Agency for Research on Cancer (IARC) classifies agents into four groups based on their carcinogenic potential. Group 1 agents are known human carcinogens; group 2A agents are probably carcinogenic to humans; group 3 agents lack data to support their role in carcinogenesis; and group 4 includes agents for which data support that they are not likely to be...

Transducer Mechanism: Nuclear Receptors

Transducer Mechanism: Nuclear Receptors

Nuclear receptors, or NRs, are unique transcription factors that regulate gene transcription and affect the cellular pathways involved in reproduction, development, or metabolism. Their ability to be stimulated by small lipophilic ligands and control vital cellular processes makes them ideal drug targets. Nearly 10-15% of currently prescribed drugs target these receptors.
About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes:

Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

Genetic polymorphisms in drug targets have emerged as critical determinants of interindividual variability in drug response and toxicity. Pharmacogenomic investigations increasingly focus on identifying these variations to personalize and optimize therapeutic interventions. A drug target may be a receptor, enzyme, or signaling protein involved in pharmacologic responses or disease-related pathways. While early pharmacogenetic studies focused primarily on drug metabolism, current research...

Articles linked to this work by shared authors, journal, and citation graph.

The role of Tec kinase signaling pathways in the development of Mallory Denk Bodies in balloon cells in alcoholic hepatitis.

Experimental and molecular pathology·2017

The role of the IL-8 signaling pathway in the infiltration of granulocytes into the livers of patients with alcoholic hepatitis.

Experimental and molecular pathology·2017

Over expression of proteins that alter the intracellular signaling pathways in the cytoplasm of the liver cells forming Mallory-Denk bodies.

Experimental and molecular pathology·2017

Upregulation of autophagy components in alcoholic hepatitis and nonalcoholic steatohepatitis.

Experimental and molecular pathology·2016

The mechanisms of Mallory-Denk body formation are similar to the formation of aggresomes in Alzheimer's disease and other neurodegenerative disorders.

Experimental and molecular pathology·2016

Systemic injection of AAV9 carrying a periostin promoter targets gene expression to a myofibroblast-like lineage in mouse hearts after reperfused myocardial infarction.

Gene therapy·2016

See all related articles