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Chen J, Hoffman BB & Isseroff RR. Beta-adrenergic receptor activation inhibits keratinocyte migration via a cyclic adenosine monophosphate-independent mechanism. J Invest Dermatol119: 1261-1268

Department of Medicine, Stanford University School of Medicine, and VA Palo Alto Health Care System, Palo Alto, CA 95616, USA.
Journal of Investigative Dermatology (Impact Factor: 6.37). 01/2003; 119(6):1261-8. DOI: 10.1046/j.1523-1747.2002.19611.x
Source: PubMed

ABSTRACT There is increasing evidence that G-protein-coupled receptors cross-talk with growth factor receptor-mediated signal transduction in a variety of cell types. We have investigated mechanisms by which the activation of beta-adrenergic receptors, classically GTP-binding proteins coupled receptors, influence the migration of cultured human keratinocytes. We found that iso-proterenol, a beta-adrenergic receptor-selective agonist, inhibited cell migration stimulated by either epidermal growth factor, or extracellular Ca2+ in a concentration-dependent manner. This was prevented by pretreatment of the cells with the beta-adrenergic receptor-selective antagonist timolol. Interestingly, isoproterenol, at a concentration of 1 nm, did not measurably increase intracellular cyclic adenosine monophosphate concentrations yet inhibited cell migration by 50%. To test further if isoproterenol's actions were mediated via activation of adenylyl cyclase, two inhibitors of its activity, 2'5'-dideoxyadenosine and SQ22536, were used. Both compounds significantly diminished iso-proterenol-induced increases in intracellular cyclic adenosine monophosphate concentrations but did not attenuate isoproterenol-induced inhibition of cell migration. Also, forskolin (1 microm) markedly increased intracellular cyclic adenosine monophosphate concentrations but did not significantly inhibit cell migration. As mitogen-activated protein kinases are known to signal growth factor-stimulated cell migration, we examined whether beta-adrenergic receptor-mediated inhibition of keratinocyte migration might occur via inactivation of mitogen-activated protein kinases. We found that isoproterenol inhibited phosphorylation of extracellular signal-regulated kinase mitogen-activated protein kinase in a concentration-dependent manner but had no effect on the phosphorylation of the stress mitogen-activated protein kinases c-jun N-terminal kinase and stress-activated protein kinase-2. Neither forskolin nor a membrane permeable cyclic adenosine monophosphate analog inhibited phosphorylation of any of these mitogen-activated protein kinases. These findings suggest that beta-adrenergic receptor-induced inhibition of keratinocyte migration is mediated through inhibition of the extracellular signal-regulated kinase mitogen-activated protein kinase signaling in a cyclic adenosine monophosphate-independent manner.

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    • "Single cell migration experiments were performed as described (Chen et al., 2002). Mouse keratinocytes were plated on glass coated with 60 μg/ml collagen I (Cohesion Technologies, Palo Alto, CA) for 3 h. "
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    • "Keratinocytes express mainly ͤ2 receptors and also ͣ1 receptors (Steinkraus et al., 1992, Drummond et al., 1996, Sivamani et al., 2007). Stimulation of ͤ-adrenergic receptors in epidermal keratinocytes results in increased cAMP production, activation of protein kinase C and formation of inositol-1,4,5-trisphosphate, calcium influx and extracellular signalrelated kinase (ERK) dephosphorylation through the action of serine/threonine phosphatase PP2A (Chen et al., 2002, Pullar et al., 2001, Schallreuter et al., 1995). Catecholamines stimulate keratinocyte differentiation with increased expression of keratins 1, 10, involucrin and transglutaminase (Mammone et al., 1998, Schallreuter et al., 1995). "
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    • "This reduction was not affected by simultanous treatment with SST. Our data fit well with findings of Chen et al., (2002) who described that activation of the b 2 -adrenergic receptor inhibits keratinocyte migration via a cAMP-independent mechanism [39]. The b 2 -adrenergic receptor is positively coupled to cAMP generation via the stimulatory G-protein Ga s [4] and Chen et al. proposed that the decrease of migration is mediated by inhibition of MAP kinase signalling. "
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