Regulation of inhibitory protein-kappaB and monocyte chemoattractant protein-1 by angiotensin II type 2 receptor-activated Src homology protein tyrosine phosphatase-1 in fetal vascular smooth muscle cells.
In the present study we examined the effects of angiotensin II (Ang II) type 2 (AT(2)) receptor stimulation on AT(1) receptor-mediated monocyte chemoattractant protein-1 (MCP-1) expression and the possible mechanisms of AT(2) receptor-mediated signaling in cultured rat fetal vascular smooth muscle cells, which express both AT(1) and AT(2) receptors. Ang II stimulation induced MCP-1 mRNA expression as well as an increase in nuclear factor-kappaB (NF-kappaB) binding to the corresponding cis DNA element of the MCP-1 promoter region and a decrease in the cytosolic inhibitory protein-kappaB (IkappaB) protein level via AT(1) receptor stimulation, whereas stimulation of the AT(2) receptor decreased Ang II-induced MCP-1 expression, NF-kappaB DNA binding, and IkappaB degradation, suggesting that activation of the AT(2) receptor attenuated AT(1) receptor-mediated MCP-1 expression via a decrease in NF-kappaB DNA binding and an increase in IkappaB stability. Moreover, we demonstrated that AT(2) receptor stimulation attenuated TNFalpha-mediated NF-kappaB activation and MCP-1 expression. A tyrosine phosphatase inhibitor, orthovanadate, attenuated the AT(2) receptor-mediated increase in IkappaB protein. Moreover, we observed that two IkappaB subunits (IkappaBalpha and IkappaBbeta) were tyrosine-phosphorylated after Ang II stimulation. Transfection of a dominant-negative Src homology protein tyrosine phosphatase-1 mutant into vascular smooth muscle cells inhibited the AT(2) receptor-mediated increase in IkappaB, leading to a significant increase in AT(1) receptor-induced NF-kappaB activation and MCP-1 expression. Taken together, our results demonstrated that AT(2) receptor stimulation attenuated MCP-1 expression via IkappaB stabilization, and Src homology protein tyrosine phosphatase-1 might play a critical role in the transcriptional regulation of MCP-1 expression through the control of IkappaB protein stability.
Wu
Lan
L
Department of Medical Biochemistry, Ehime University School of Medicine, Shigenobu, Onsen-gun, Ehime 791-0295, Japan.
Iwai
Masaru
M
Li
Zhen
Z
Shiuchi
Tetsuya
T
Min
Li-Juan
LJ
Cui
Tai-Xing
TX
Li
Jian-Mei
JM
Okumura
Midori
M
Nahmias
Clara
C
Horiuchi
Masatsugu
M
D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000494:pharmacology; D047228:Angiotensin II Type 1 Receptor Blockers; D057912:Angiotensin II Type 2 Receptor Blockers; D000818:Animals; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation; D020672:I-kappa B Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D009154:Mutation; D016328:NF-kappa B; D009842:Oligopeptides / Q000494:pharmacology; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000187:drug effects / Q000378:metabolism; D044139:Receptor, Angiotensin, Type 2 / Q000187:drug effects / Q000378:metabolism*
D047228:Angiotensin II Type 1 Receptor Blockers; D057912:Angiotensin II Type 2 Receptor Blockers; D018932:Chemokine CCL2; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D007093:Imidazoles; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009842:Oligopeptides; D011725:Pyridines; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D000804:Angiotensin II; C060894:CGP 42112A; C073402:PD 123319; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C509250:Ptpn6 protein, rat