title: Angiotensin II activates NF-κB through AT1A receptor recruitment of β-arrestin in cultured rat vascular smooth muscle cells.
abstract: Activation of the angiotensin type 1A receptor (AT1AR) in rat aorta vascular smooth muscle cells (RASMC) results in increased synthesis of the proinflammatory enzyme cyclooxygenase-2 (COX-2). We previously showed that nuclear localization of internalized AT1AR results in activation of transcription of the gene for COX-2, i.e., prostaglandin-endoperoxide synthase-2. Others have suggested that ANG II stimulation of COX-2 protein synthesis is mediated by NF-κB. The purpose of the present study was to examine the interrelationship between AT1AR activation, β-arrestin recruitment, and NF-κB activation in the ability of ANG II to increase COX-2 protein synthesis in RASMC. In the present study we utilized RASMC, inhibitors of the NF-κB pathway, β-arrestin knockdown, radioligand binding, immunoblotting, and immunofluorescence to characterize the roles of AT1AR internalization, NF-κB activation, and β-arrestin in ANG II-induced COX-2 synthesis. Ro-106-9920 or parthenolide, agents that inhibit the initial steps of NF-κB activation, blocked ANG II-induced p65 NF-κB nuclear localization, COX-2 protein expression, β-arrestin recruitment, and AT1AR internalization without inhibiting ANG II-induced p42/44 ERK activation. Curcumin, an inhibitor of NF-κB-induced transcription, blocked ANG II-induced COX-2 protein expression without altering AT1AR internalization, ANG II-induced p65 NF-κB nuclear localization, or p42/44 ERK activation. Small interfering RNA-induced knockdown of β-arrestin-1 and -2 inhibited ANG II-induced p65 NF-κB nuclear localization. In vascular smooth muscle cells, internalization of the activated AT1AR mediated by β-arrestins activates the NF-κB pathway, producing nuclear localization of the transcription factor and initiation of COX-2 protein synthesis, thereby linking internalization of the receptor with the NF-κB pathway.
authors.affiliation: Division of Nephrology, Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA. morinelt@musc.edu
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Morinelli
authors.forename: Mi-Hye
authors.initials: MH
authors.lastname: Lee
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Kendall
authors.forename: Louis M
authors.initials: LM
authors.lastname: Luttrell
authors.forename: Linda P
authors.initials: LP
authors.lastname: Walker
authors.forename: Michael E
authors.initials: ME
authors.lastname: Ullian
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology* / Q000502:physiology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D019390:Arrestins / Q000378:metabolism*; D002478:Cells, Cultured; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins
chemical_list: C000605253:ARRB1 protein, human; C000605256:Arrb1 protein, rat; D019390:Arrestins; D016328:NF-kappa B; D044140:Receptor, Angiotensin, Type 1; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins; D000804:Angiotensin II
keywords: NF-κB; angiotensin receptor; cyclooxygenase-2; signal transduction; vascular smooth muscle cells; β-arrestins