Pertussis toxin up-regulates angiotensin type 1 receptors through Toll-like receptor 4-mediated Rac activation.
Pertussis toxin (PTX) is recognized as a specific tool that uncouples receptors from G(i) and G(o) through ADP-ribosylation. During the study analyzing the effects of PTX on Ang II type 1 receptor (AT1R) function in cardiac fibroblasts, we found that PTX increases the number of AT1Rs and enhances AT1R-mediated response. Microarray analysis revealed that PTX increases the induction of interleukin (IL)-1beta among cytokines. Inhibition of IL-1beta suppressed the enhancement of AT1R-mediated response by PTX. PTX increased the expression of IL-1beta and AT1R through NF-kappaB, and a small GTP-binding protein, Rac, mediated PTX-induced NF-kappaB activation through NADPH oxidase-dependent production of reactive oxygen species. PTX induced biphasic increases in Rac activity, and the Rac activation in a late but not an early phase was suppressed by IL-1beta siRNA, suggesting that IL-1beta-induced Rac activation contributes to the amplification of Rac-dependent signaling induced by PTX. Furthermore, inhibition of TLR4 (Toll-like receptor 4) abolished PTX-induced Rac activation and enhancement of AT1R function. However, ADP-ribosylation of G(i)/G(o) by PTX was not affected by inhibition of TLR4. Thus, PTX binds to two receptors; one is TLR4, which activates Rac, and another is the binding site that is required for ADP-ribosylation of G(i)/G(o).
Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582.
Motohiro
M
Nishida
Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582.
Reiko
R
Suda
Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582.
Yuichi
Y
Nagamatsu
Division of Cellular and Gene Therapy Products, National Institute of Health Sciences, Setagaya, Tokyo 158-8501.
Shihori
S
Tanabe
Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582.
Naoya
N
Onohara
Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582.
Michio
M
Nakaya
Department of Physiological Chemistry, Graduate School of Comprehensive Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba 305-8575.
Yasunori
Y
Kanaho
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
Takahiro
T
Shibata
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
Koji
K
Uchida
Department of Biochemistry, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582.
Hideki
H
Sumimoto
Division of Cellular and Gene Therapy Products, National Institute of Health Sciences, Setagaya, Tokyo 158-8501.
Yoji
Y
Sato
Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582. Electronic address: kurose@phar.kyushu-u.ac.jp.
Hitoshi
H
Kurose
D000803:Angiotensin I / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D007375:Interleukin-1 / Q000096:biosynthesis; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D037342:Pertussis Toxin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D011945:Receptors, Angiotensin / Q000187:drug effects* / Q000378:metabolism; D051193:Toll-Like Receptors / Q000502:physiology*; D015854:Up-Regulation / Q000187:drug effects*; D020744:rac GTP-Binding Proteins / Q000378:metabolism*
D007375:Interleukin-1; D017382:Reactive Oxygen Species; D011945:Receptors, Angiotensin; D051193:Toll-Like Receptors; D000803:Angiotensin I; D037342:Pertussis Toxin; D020744:rac GTP-Binding Proteins