Upregulation of early growth response factor-1 by bile acids requires mitogen-activated protein kinase signaling

Journal Article · Mon Feb 15 00:00:00 EST 2010 · Toxicology and Applied Pharmacology

DOI:https://doi.org/10.1016/j.taap.2009.11.013· OSTI ID:21344866

Allen, Katryn ^[1]; Kim, Nam Deuk; Moon, Jeon-OK ^[1]

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1. Department of Pharmacology, Toxicology, and Experimental Therapeutics, University of Kansas Medical Center, 4063 KLSIC, 3901 Rainbow Boulevard, Kansas City, KS 66160 (United States)

Cholestasis results when excretion of bile acids from the liver is interrupted. Liver injury occurs during cholestasis, and recent studies showed that inflammation is required for injury. Our previous studies demonstrated that early growth response factor-1 (Egr-1) is required for development of inflammation in liver during cholestasis, and that bile acids upregulate Egr-1 in hepatocytes. What remains unclear is the mechanism by which bile acids upregulate Egr-1. Bile acids modulate gene expression in hepatocytes by activating the farnesoid X receptor (FXR) and through activation of mitogen-activated protein kinase (MAPK) signaling. Accordingly, the hypothesis was tested that bile acids upregulate Egr-1 in hepatocytes by FXR and/or MAPK-dependent mechanisms. Deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) stimulated upregulation of Egr-1 to the same extent in hepatocytes isolated from wild-type mice and FXR knockout mice. Similarly, upregulation of Egr-1 in the livers of bile duct-ligated (BDL) wild-type and FXR knockout mice was not different. Upregulation of Egr-1 in hepatocytes by DCA and CDCA was prevented by the MEK inhibitors U0126 and SL-327. Furthermore, pretreatment of mice with U0126 prevented upregulation of Egr-1 in the liver after BDL. Results from these studies demonstrate that activation of MAPK signaling is required for upregulation of Egr-1 by bile acids in hepatocytes and for upregulation of Egr-1 in the liver during cholestasis. These studies suggest that inhibition of MAPK signaling may be a novel therapy to prevent upregulation of Egr-1 in liver during cholestasis.

• OSTI ID: 21344866
• Journal Information: Toxicology and Applied Pharmacology, Vol. 243, Issue 1; Other Information: DOI: 10.1016/j.taap.2009.11.013; PII: S0041-008X(09)00479-7; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0041-008X
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
BILE ACIDS
BILIARY TRACT
ENZYME INHIBITORS
GENES
INFLAMMATION
LIVER
LIVER CELLS
MICE
PHOSPHOTRANSFERASES
RECEPTORS
THERAPY
ANIMAL CELLS
ANIMALS
BODY
CARBOXYLIC ACIDS
DIGESTIVE SYSTEM
ENZYMES
GLANDS
HYDROXY COMPOUNDS
MAMMALS
MEDICINE
MEMBRANE PROTEINS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PATHOLOGICAL CHANGES
PHOSPHORUS-GROUP TRANSFERASES
PROTEINS
RODENTS
SOMATIC CELLS
STEROIDS
STEROLS
SYMPTOMS
TRANSFERASES
VERTEBRATES