Differential Regulation Of Cysteinyl Leukotriene Receptor Signaling By Protein Kinase C In Human Mast Cells
activation; antagonist; asthmatic subjects; desensitization; expression; hyperresponsiveness; intestinal epithelial-cells; proliferation; pulmonary inflammation; responses; Science & Technology - Other Topics
Cysteinyl leukotrienes (cys-LTs) are a group of lipid mediators that are potent bronchoconstrictors, powerful inducers of vascular leakage and potentiators of airway hyperresponsiveness. Cys-LTs play an essential role in asthma and are synthesized as well as activated in mast cells (MCs). Cys-LTs relay their effects mainly through two known GPCRs, CysLT(1)R and CysLT(2)R. Although protein kinase C (PKC) isoforms are implicated in the regulation of CysLT(1)R function, neither the role of PKCs in cys-LT-dependent MC inflammatory signaling nor the involvement of specific isoforms in MC function are known. Here, we show that PKC inhibition augmented LTD4 and LTE4-induced calcium influx through CysLT(1)R in MCs. In contrast, inhibition of PKCs suppressed c-fos expression as well MIP1 beta generation by cys-LTs. Interestingly, cys-LTs activated both PKC alpha and PKC epsilon isoforms in MC. However, knockdown of PKC alpha augmented cys-LT mediated calcium flux, while knockdown of PKC epsilon attenuated cys-LT induced c-fos expression and MIP1 beta generation. Taken together, these results demonstrate for the first time that cys-LT signaling downstream of CysLT(1)R in MCs is differentially regulated by two distinct PKCs which modulate inflammatory signals that have significant pathobiologic implications in allergic reactions and asthma pathology.
Kondeti V; Duah E; Al-Azzam N; Thodeti C K; Boyce J A; Paruchuri S
Plos One
2013
2013-08
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1371/journal.pone.0071536" target="_blank" rel="noreferrer noopener">10.1371/journal.pone.0071536</a>
Changes of the responses of single sympathetic ganglionic neurones to substance P following desensitization
adenylate-cyclase; binding; cells; desensitization; G protein; inhibition; k+ current; kinase-c; M current; muscarine; Neurosciences & Neurology; Pharmacology & Pharmacy; phosphorylation; protein alpha-subunits; receptor; rgs proteins; Substance P
1 The neuropeptide substance P (SP) exerts an excitatory effect on sympathetic neurones by inhibiting a time- and voltage-dependent potassium current. During prolonged application of SP, the response desensitizes. The changes in kinetics of the SP response in single neurones after desensitization have been studied in an attempt to gain some insight as to the molecular mechanism of desensitization in live, functioning neurones. 2 Desensitization to SP resulted in subsequent SP responses being smaller, but the time course was unchanged in desensitized cells compared with non-desensitized cells. 3 Experimental manipulations were performed to decrease receptor and G protein function for comparison to desensitization. Intracellular application of GDP betaS, to decrease G protein function, led to successive responses to agonist becoming smaller and slower. When functional muscarinic receptors were decreased by extracellular application of propylbenzilylcholine mustard (PrBCM), the response to muscarine became smaller, but the time course was unchanged compared with the change in time course produced by PrBCM vehicle alone. 4 The results have also been compared with simulations from a mathematical model of drug-receptor-G protein interactions. Under a constrained set of conditions, the model predicts that decreasing the size of the G protein pool will decrease both the magnitude and the time course of the response to agonist. Decreasing receptor levels results in a more efficient decrease in the magnitude of the response but no change in the time course of the response. 5 These data provide evidence that desensitization of the response to SP in single neurones results from a decrease in functional receptors.
Simmons M A
Journal of Autonomic Pharmacology
2001
2001-04
Journal Article
<a href="http://doi.org/10.1046/j.1365-2680.2001.00214.x" target="_blank" rel="noreferrer noopener">10.1046/j.1365-2680.2001.00214.x</a>
Lung edema clearance: 20 years of progress selected contribution: Long-term effects of beta(2)-adrenergic receptor stimulation on alveolar fluid clearance in mice
acute lung injury; alveolar; beta-adrenergic-receptor; desensitization; down-regulation; epithelium; hydrostatic pulmonary-edema; in-vivo; liquid clearance; lung fluid balance; messenger-rna; Physiology; pulmonary edema; rat lung; resolution; sodium transport; Sport Sciences
Stimulation of active fluid transport with beta-adrenergic receptor (betaAR) agonists can accelerate the resolution of alveolar edema. However, chronic betaAR-agonist administration may cause betaAR desensitization and downregulation that may impair physiological responsiveness to betaAR-agonist stimulation. Therefore, we measured baseline and terbutaline- (10(-3) M) stimulated alveolar fluid clearance in mice that received subcutaneously (miniosmotic pumps) either saline or albuterol (2 mg.kg(-1).day(-1)) for 1, 3, or 6 days. Continuous albuterol administration increased plasma albuterol levels (10(-5) M), an effect that was associated with 1) a significant decrease in betaAR density and 2) attenuation, but not ablation, of maximal terbutaline- induced cAMP production. Forskolin-mediated cAMP-release was unaffected. Continuous albuterol infusion stimulated alveolar fluid clearance on day 1 but did not increase alveolar fluid clearance on days 3 and 6. However, terbutaline- stimulated alveolar fluid clearance in albuterol-treated mice was not reduced compared with saline-treated mice. Despite significant reductions in betaAR density and agonist-mediated cAMP production by long-term betaAR-agonist exposure, maximal betaAR-agonist-mediated increase in alveolar fluid clearance is not diminished in mice.
Sartori C; Fang X; McGraw D W; Koch P; Snider M E; Folkesson H G; Matthay M A
Journal of Applied Physiology
2002
2002-11
Journal Article
<a href="http://doi.org/10.1152/japplphysiol.00275.2002" target="_blank" rel="noreferrer noopener">10.1152/japplphysiol.00275.2002</a>
PKA delivery to the distal lung air spaces increases alveolar liquid clearance after isoproterenol-induced alveolar epithelial PKA desensitization.
Adrenergic beta-Agonists/*pharmacology; Animals; Body Fluids/physiology; Cyclic AMP-Dependent Protein Kinases/*administration & dosage; Desensitization; Extravascular Lung Water/metabolism; Immunologic; Isoproterenol/*pharmacology; Male; Pulmonary Alveoli/cytology/*drug effects/*metabolism; Pulmonary Circulation/physiology; Pulmonary Edema/metabolism; Rats; Respiratory Mucosa/cytology/drug effects/metabolism; Sprague-Dawley
Isoproterenol (Iso) infusion for 48 h in rats decreases the ability of beta-adrenoceptor (beta-AR) agonists to increase alveolar liquid clearance (ALC). An impairment in protein kinase A (PKA) function appears to be critical in producing the desensitized ALC response. To test this hypothesis, we used a novel protein delivery reagent (Chariot, Active Motif) to deliver either the PKA catalytic subunit or the PKA holoenzyme to the distal lung epithelium of Iso-infused rats (400 microg.kg(-1).h(-1), 48 h). After this infusion, ALC was measured by mass balance over 2 h. ALC in Iso-infused rats was 27.9% (SD 5.8) of instilled volume absorbed. Delivery of the catalytic PKA subunit to Iso-infused rats increased ALC to 47.7% (SD 8.9) (P \textless 0.05). ALC in Iso-infused rats delivered the inactive PKA holoenzyme [29.6% (SD 2.5)] was not increased above baseline values. Subsequent holoenzyme activation by intravenous infusion of the stable cAMP analog Sp-8-Bromo-cAMPS increased ALC to 41.7% (SD 8.8) (P \textless 0.05). Immunohistochemical localization of Chariot-delivered PKA revealed staining in the alveolar and distal airway epithelium. These data indicate that protein delivery reagents can be used to rapidly deliver biologically active proteins to the distal lung epithelium and that PKA desensitization may be an important rate-limiting event in the development of Iso-induced desensitization of the alveolar epithelial beta-AR signaling pathway.
Maron Michael B; Folkesson Hans G; Stader Sonya M; Walro Jon M
American journal of physiology. Lung cellular and molecular physiology
2005
2005-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/ajplung.00134.2004" target="_blank" rel="noreferrer noopener">10.1152/ajplung.00134.2004</a>