title: Non-raft adenylyl cyclase 2 defines a cAMP signaling compartment that selectively regulates IL-6 expression in airway smooth muscle cells: differential regulation of gene expression by AC isoforms.
abstract: Adenylyl cyclase (AC) isoforms differ in their tissue distribution, cellular localization, regulation, and protein interactions. Most cell types express multiple AC isoforms. We hypothesized that cAMP produced by different AC isoforms regulates unique cellular responses in human bronchial smooth muscle cells (BSMC). Overexpression of AC2, AC3, or AC6 had distinct effects on forskolin (Fsk)-induced expression of a number of known cAMP-responsive genes. These data show that different AC isoforms can differentially regulate gene expression. Most notable, overexpression and activation of AC2 enhanced interleukin 6 (IL-6) expression, but overexpression of AC3 or AC6 had no effect. IL-6 production by BSMC was induced by Fsk and select G protein-coupled receptor (GPCR) agonists, though IL-6 levels did not directly correlate with global cAMP levels. Treatment with PKA selective 6-Bnz-cAMP or Epac selective 8-CPT-2Me-cAMP cAMP analogs revealed a predominant role for PKA in cAMP-mediated induction of IL-6. IL-6 promoter mutations demonstrated that AP-1 and CRE transcription sites were required for Fsk to stimulate IL-6 expression. Our present study defines an AC2 cAMP signaling compartment that specifically regulates IL-6 expression in BSMC via Epac and PKA and demonstrates that other AC isoforms are excluded from this pool.
authors.affiliation: Department of Pharmacology, University of Tennessee Health Science Center, 874 Union Ave., Crowe 115, Memphis, TN, 38163, USA.
authors.forename: Amy S
authors.initials: AS
authors.lastname: Bogard
authors.forename: Anna V
authors.initials: AV
authors.lastname: Birg
authors.forename: Rennolds S
authors.initials: RS
authors.lastname: Ostrom
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D001980:Bronchi / Q000166:cytology; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005786:Gene Expression Regulation; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D007527:Isoenzymes / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D020662:Guanine Nucleotide Exchange Factors; C508600:IL6 protein, human; D015850:Interleukin-6; D007527:Isoenzymes; C116122:RAPGEF3 protein, human; D012333:RNA, Messenger; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000262:Adenylyl Cyclases