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Fig. 6 | Respiratory Research

Fig. 6

From: Dexamethasone rescues TGF-β1-mediated β2-adrenergic receptor dysfunction and attenuates phosphodiesterase 4D expression in human airway smooth muscle cells

Fig. 6

A proposed model of GC-mediated rescue of TGF-β1-induced hyporesponsiveness to bronchodilators. We previously demonstrated that TGF-β1 induces Smad2/3 activation to increase pde4d expression, leading to increased cAMP hydrolysis and attenuating HASM cell relaxation responses. We posited that DEX binds to the glucocorticoid receptor (GR), inhibiting both increased pde4d expression and rescuing TGF-β1-induced attenuation of β2AR and Gαs-induced cAMP production. AC = Adenylyl Cyclase; β2AR = β2-adrenergic receptor; DEX = Dexamethasone; Gαs = Stimulatory Gα protein; GR = Glucocorticoid Receptor; PDE4D = Phosphodiesterase 4D; TBR-I/II = TGF-β receptor I/II; pMLC = phosphorylated myosin light chain

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