Cyclic AMP-dependent Transcriptional Up-regulation of Phosphodiesterase 4D5 in Human Airway Smooth Muscle Cells

Abstract

Phosphodiesterase 4D (PDE4D), part of the complex cAMP-specific PDE4 family, plays a pivotal role in the regulation of airway smooth muscle relaxation by catalyzing the hydolysis of cAMP. Its gene on chromosome 5q12 encodes 5 splice variants, which show tissue-dependent expression and regulation. The genomic arrangement of PDE4D was determined using in silico methods, and a putative promoter of one of the protein kinase A-activated, long isoforms, PDE4D5 was identified. Promoter-luciferase constructs, transiently transfected into a ␤ 2 adrenoreceptor-expressing CHO-K1 cell line, were used to demonstrate that the PDE4D5 promoter up-regulated reporter gene expression in response to increased cell cAMP. Site-directed mutagenesis of the cAMP-response element (CRE) at position ؊201 identified this as the principal component of the mechanism underlying this cAMP responsiveness. In the second part of this study, cAMP-dependent induction of PDE4D5 transcript in primary cultured human airway smooth muscle cells (hASMs) was demonstrated using both qualitative reverse-transcriptase PCR and quantitative real-time PCR. Isolated PDE4D5 isoenzyme activity, measured after selective immunoprecipitation from hASMs, confirmed that this increase in expression led to an up-regulation of functional activity. We present evidence for cAMP-driven PDE4D5 up-regulation in hASMs and suggest a CRE-containing, isoform-specific promoter as the primary mechanism.

A whole genome association study of neuroticism using DNA pooling

“…For example, a CRE (TGACGTT) in the promoter of an isoform of PDE4D (PDE4D5) was shown to be involved in the cAMP responsiveness of the PDE4D5 promoter. 60 Several other lines of evidence support the involvement of the PDE4D gene in susceptibility to neuroticism and depression. A PDE4-specific inhibitor rolipram has antidepressant effects on animals and patients with major depression.…”

Long-term regulation of cyclic nucleotide phosphodiesterase type 3B and 4 in 3T3-L1 adipocytes

“…The stimulatory effects of β-adrenergic receptor agonists on PDE4D expression might be mediated by CREB since CRE elements have been identified in the PDE4D promoter [29]. In cells other than adipocytes it has also been shown that prolonged exposition to cAMP-increasing agents results in PDE4D up-regulation.…”

The human near‐term myometrial β3‐adrenoceptor but not the β2‐adrenoceptor is resistant to desensitisation after sustained agonist stimulation

“…It has been demonstrated, in different human blood cells, that treatment with either b 2 -AR agonists (Manning et al, 1996;Seybold et al, 1998;Ortiz et al, 2000) or with a cAMP structural analogue, 8-Bromo-cAMP, leads to an upregulation of PDE4 enzymes. More recently, new evidences for a role of cAMP on PDE4 promoters have been defined (Vicini & Conti, 1997;D'Sa et al, 2002;Le Jeune et al, 2002). Furthermore, it has been shown, in an in vivo model of rat pulmonary b 2 -AR desensitisation induced by salbutamol, that the b 2 -AR binding site density was significantly reduced, and associated with an increase in the PDE3 and PDE4 activities in lung membranes of these animals (Finney et al, 2000).…”