Hypertonicity-induced expression of monocyte chemoattractant protein-1 through a novel cis-acting element and MAPK signaling pathways.
MCP1 is upregulated by various stimuli, including LPS, high glucose, and hyperosmolality. However, the molecular mechanisms of transcriptional regulation of the MCP1 gene under hyperosmolar conditions are poorly understood. Treatment of NRK52E cells with NaCl or mannitol resulted in significant elevation of MCP1 mRNA and protein in a time- and dose-dependent manner. Treatment with a p38MAPK inhibitor (SB203580), an ERK inhibitor (PD98059), or an MEK inhibitor (U0126), suppressed the increase in MCP1 expression caused by hypertonic NaCl, whereas a JNK inhibitor (SP600125) and an AP1 inhibitor (curcumin) failed to attenuate MCP1 mRNA expression by NaCl. In the 5'-flanking region of the MCP1 gene, there is a sequence motif similar to the consensus TonE/ORE as well as the consensus C/E binding protein (BP), NF-kappaB, and AP1/Sp1 sites. Luciferase activity in cells transfected with reporter constructs containing a putative TonE/ORE element (MCP1-TonE/ORE) enhanced reporter gene expression under hypertonic stress. Results of electrophoretic gel mobility shift assay showed a slow migration of the MCP1-TonE/ORE probe, representing the binding of TonEBP/OREBP/NFAT5 to this enhancer element. These results indicate that the 5'-flanking region of MCP1 contains a hypertonicity-sensitive cis-acting element, MCP1-TonE/ORE, as a novel element in the MCP1 gene. Furthermore, p38MAPK and MEK-ERK pathways appear to be, at least in part, involved in hypertonic stress-mediated regulation of MCP1 expression through the MCP1-TonE/ORE.
Kojima
Ryoji
R
Laboratory of Analytical Pharmacology, Faculty of Pharmacy, Meijo University, Nagoya 468-8503, Japan. kojima@ccmfs.meijo-u.ac.jp
Taniguchi
Hajime
H
Tsuzuki
Aya
A
Nakamura
Kanako
K
Sakakura
Yumi
Y
Ito
Mikio
M
D020121:5' Untranslated Regions / Q000276:immunology; D000818:Animals; D002460:Cell Line; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000235:genetics*; D016384:Consensus Sequence / Q000276:immunology; D004742:Enhancer Elements, Genetic / Q000235:genetics / Q000276:immunology*; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D006982:Hypertonic Solutions / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000235:genetics* / Q000276:immunology*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000502:physiology; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000502:physiology; D050778:NFATC Transcription Factors / Q000378:metabolism; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000502:physiology
D020121:5' Untranslated Regions; C491766:Ccl2 protein, rat; D018932:Chemokine CCL2; D006982:Hypertonic Solutions; D050778:NFATC Transcription Factors; C492199:Nfat5 protein, rat; D014157:Transcription Factors; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases