Anti-mitogenic effects of β-agonists and PGE2 on airway smooth muscle are PKA dependent.
Inhaled β-agonists are effective airway smooth muscle (ASM)-relaxing agents that help reverse bronchoconstriction in asthma, but their ability to affect the aberrant ASM growth that also occurs with asthma is poorly understood. β-Agonists exhibit PKA-dependent antimitogenic effects in several cell types. However, recent studies suggest that Epac, and not PKA, mediates the antimitogenic effect of cAMP in both ASM and fibroblasts. This study aims to clarify the role of PKA in mediating the effect of G(s)-coupled receptors on human ASM growth. Pretreatment of ASM cultures with β-agonists albuterol, isoproterenol, or salmeterol (100 nM to 10 μM) caused a significant (∼ 25-30%) inhibition of EGF-stimulated ASM thymidine incorporation and cell proliferation, whereas a much greater inhibition was observed from pretreatment with PGE(2) (75-80%). However, all agents were ineffective in cells expressing GFP chimeras of either PKI (a PKA inhibitor) or a mutant PKA regulatory subunit relative to the control cells expressing GFP. The antimitogenic efficacy of PGE(2) in inhibiting control cultures was associated with greater ability to stimulate sustained PKA activation and greater inhibition of late-phase promitogenic p42/p44 and PI3K activities. These findings suggest that therapeutic approaches enabling superior PKA activation in ASM will be most efficacious in deterring ASM growth.
Yan
Huandong
H
Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201-1075, USA.
Deshpande
Deepak A
DA
Misior
Anna M
AM
Miles
Matthew C
MC
Saxena
Himansh
H
Riemer
Ellen C
EC
Pascual
Rodolfo M
RM
Panettieri
Reynold A
RA
Penn
Raymond B
RB
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D058666:Adrenergic beta-2 Receptor Agonists / Q000494:pharmacology*; D000420:Albuterol / Q000031:analogs & derivatives / Q000494:pharmacology; D001993:Bronchodilator Agents / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D007545:Isoproterenol / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000187:drug effects* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D000068299:Salmeterol Xinafoate; D013997:Time Factors; D014132:Trachea / Q000166:cytology; D014162:Transfection
D048868:Adaptor Proteins, Signal Transducing; D058666:Adrenergic beta-2 Receptor Agonists; D000420:Albuterol; D001993:Bronchodilator Agents; D017868:Cyclic AMP-Dependent Protein Kinases; D015232:Dinoprostone; D004815:Epidermal Growth Factor; D049452:Green Fluorescent Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007545:Isoproterenol; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019869:Phosphatidylinositol 3-Kinases; D000068299:Salmeterol Xinafoate; C491526:PKIA protein, human
Am J Respir Cell Mol Biol. 2009 Jul;41(1):24-39
19059887
Br J Pharmacol. 2001 Aug;133(8):1201-12
11498504
FASEB J. 2008 Jul;22(7):2134-41
18337459
Am J Respir Cell Mol Biol. 1998 Aug;19(2):338-48
9698608
FASEB J. 2006 Jul;20(9):1558-60
16723377
Am J Physiol Lung Cell Mol Physiol. 2008 Jan;294(1):L131-8
17993585
Mol Pharmacol. 2008 Feb;73(2):566-74
17993511
Br J Pharmacol. 2010 Jan 1;159(2):265-84
19912228
Cell Signal. 2006 Dec;18(12):2105-20
16828259
Biochemistry. 2005 Oct 25;44(42):13771-82
16229467
Am J Respir Cell Mol Biol. 2000 Oct;23(4):546-54
11017921
Biochem Pharmacol. 1995 Jun 16;49(12):1809-19
7598743
Am J Physiol. 1999 Sep;277(3):L479-88
10484455
Br J Pharmacol. 1997 Jun;121(3):361-8
9179374
Am J Respir Cell Mol Biol. 2003 Feb;28(2):257-62
12540494
Biochemistry. 2008 Sep 2;47(35):9279-88
18690720
J Biol Chem. 1971 Apr 10;246(7):1977-85
4324557
J Biol Chem. 1989 Oct 5;264(28):16672-8
2550452
Mol Pharmacol. 2003 Dec;64(6):1357-69
14645666
Respir Res. 2009 Sep 29;10:88
19788733
Naunyn Schmiedebergs Arch Pharmacol. 2008 Aug;378(2):149-69
18278482
Naunyn Schmiedebergs Arch Pharmacol. 2008 Dec;378(6):617-30
18648773
Br J Pharmacol. 1998 Feb;123(4):701-11
9517390
Am J Physiol. 1994 Sep;267(3 Pt 1):L291-9
7943256
J Biol Chem. 1994 May 20;269(20):14509-17
8182057
Biochemistry. 2005 Nov 8;44(44):14595-605
16262259
J Allergy Clin Immunol. 2004 Aug;114(2 Suppl):S2-17
15309015
Mol Pharmacol. 1999 Nov;56(5):1079-86
10531416
J Pharmacol Exp Ther. 1999 Feb;288(2):428-37
9918542
Am J Respir Cell Mol Biol. 2008 Oct;39(4):482-9
18421013