Tag: signaling

Posted on

Bidirectional Cross-Regulation between the Endothelial Nitric Oxide Synthase and ?-Catenin Signaling Pathways.

Bidirectional Cross-Regulation between the Endothelial Nitric Oxide Synthase and ?-Catenin Signaling Pathways.

Cardiovasc Res. 2014 Jul 25;

Authors: Warboys CM, Chen N, Zhang Q, Shaifta Y, Vanderslott G, Passacquale G, Hu Y, Xu Q, Ward JP, Ferro A

Abstract
AIMS: ?-catenin has been shown to be regulated by inducible nitric oxide synthase (NOS) in endothelial cells. We investigated here whether ?-catenin interacts with and regulates endothelial NOS (eNOS) and whether eNOS activation promotes ?-catenin signaling.
METHODS AND RESULTS: We identified ?-catenin as a novel eNOS binding protein in human umbilical vein endothelial cells (HUVECs) by mass spectroscopy and western blot analyses of ?-catenin and eNOS immunoprecipitates. This was confirmed by in situ proximity ligation assay. eNOS activity, assessed by cGMP production and eNOS phosphorylation (Ser1177), was enhanced in ?-catenin(-/-) mouse pulmonary endothelial cells (MPECs) relative to wild type MPECs. eNOS activation (using adenosine, salbutamol, thrombin or histamine), or application of an NO donor (spermine NONOate) or cGMP-analogue (8-bromo-cGMP) caused nuclear translocation of ?-catenin in HUVEC as shown by western blotting of nuclear extracts. Exposure to spermine NONOate, 8-bromo-cGMP or sildenafil (a phosphodiesterase type 5 inhibitor) also increased the expression of ?-catenin-dependent transcripts, IL-8 and cyclin D1. Stimulation of wild type MPECs with basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), spermine NONOate, 8-bromo-cGMP or sildenafil increased tube length relative to controls in an angiogenesis assay. These responses were abrogated in ?-catenin(-/-) MPECs, with the exception of that to bFGF which is NO-independent. In C57BL/6 mice, subcutaneous VEGF-supplemented Matrigel plugs containing ?-catenin(-/-) MPECs exhibited reduced angiogenesis compared to plugs containing wild type MPECs. Angiogenesis was not altered in bFGF-supplemented Matrigel.
CONCLUSIONS: These data reveal bidirectional cross talk and regulation between the NO-cGMP and ?-catenin signaling pathways.

PMID: 25062958 [PubMed – as supplied by publisher]

View full post on pubmed: asthma

Posted on

Altered CD38/Cyclic ADP-Ribose Signaling Contributes to the Asthmatic Phenotype.

Related Articles

Altered CD38/Cyclic ADP-Ribose Signaling Contributes to the Asthmatic Phenotype.

J Allergy (Cairo). 2012;2012:289468

Authors: Jude JA, Dileepan M, Panettieri RA, Walseth TF, Kannan MS

Abstract
CD38 is a transmembrane glycoprotein expressed in airway smooth muscle cells. The enzymatic activity of CD38 generates cyclic ADP-ribose from ?-NAD. Cyclic ADP-ribose mobilizes intracellular calcium during activation of airway smooth muscle cells by G-protein-coupled receptors through activation of ryanodine receptor channels in the sarcoplasmic reticulum. Inflammatory cytokines that are implicated in asthma upregulate CD38 expression and increase the calcium responses to contractile agonists in airway smooth muscle cells. The augmented intracellular calcium responses following cytokine exposure of airway smooth muscle cells are inhibited by an antagonist of cyclic ADP-ribose. Airway smooth muscle cells from CD38 knockout mice exhibit attenuated intracellular calcium responses to agonists, and these mice have reduced airway response to inhaled methacholine. CD38 also contributes to airway hyperresponsiveness as shown in mouse models of allergen or cytokine-induced inflammatory airway disease. In airway smooth muscle cells obtained from asthmatics, the cytokine-induced CD38 expression is significantly enhanced compared to expression in cells from nonasthmatics. This differential induction of CD38 expression in asthmatic airway smooth muscle cells stems from increased activation of MAP kinases and transcription through NF-?B, and altered post-transcriptional regulation through microRNAs. We propose that increased capacity for CD38 signaling in airway smooth muscle in asthma contributes to airway hyperresponsiveness.

PMID: 23213344 [PubMed – in process]

View full post on pubmed: asthma

Posted on

The G protein-coupled receptor OGR1 mediates diverse signaling and contraction of airway smooth muscle in response to small reductions in extracellular pH.

The G protein-coupled receptor OGR1 mediates diverse signaling and contraction of airway smooth muscle in response to small reductions in extracellular pH.

Br J Pharmacol. 2011 Dec 6;

Authors: Saxena H, Deshpande DA, Tiegs BC, Yan H, Battafarano RJ, Burrows WM, Damera G, Panettieri RA, Dubose TD, An SS, Penn RB

Abstract
Background and Purpose.? Previous studies have linked a reduction of pH in the airway, caused by either environmental factors, microaspiration of gastric acid, or inflammation, with airway smooth muscle (ASM) contraction and increased airway resistance. Neural mechanisms have been shown capable of mediating airway contraction in response to reductions in airway pH to values of < pH 6.5; whether reduced extracellular pH (pHo) has direct effects on ASM is unknown. Experimental Approach.? Intracellular signaling events stimulated by ?pHo in cultured human ASM cells were examined by immunoblotting, phosphoinositide hydrolysis and calcium mobilization assays. ASM cell contractile state was examined using Magnetic Twisting Cytometry. Expression of putative proton-sensing G protein-coupled receptors (GPCRs) in ASM was assessed by real-time PCR. The role of OGR1 in acid-induced ASM signaling and contraction was assessed in cultures subjected to siRNA-mediated OGR1 knockdown. Key Results.? ASM cells responded to incremental reductions in pHo (from pH 8.0-6.8) by activating multiple signaling pathways, involving p42/p44, Akt, PKA, and calcium mobilization. Coincidently, ASM cells contracted in response to decreased pHo with similar “dose” dependence. Real-time PCR suggested OGR1 was the only proton-sensing GPCR expressed in ASM cells. Both acid-induced signaling (excepting Akt activation) and contraction were significantly attenuated by knockdown of OGR1. Conclusions and Implications.? These studies reveal OGR1 to be a physiologically-relevant GPCR in ASM cells, capable of pleiotropic signaling and mediation of contraction in response to small reductions in extracellular pH. Accordingly, ASM OGR1 may contribute to asthma pathology and represent a therapeutic target in obstructive lung diseases.

PMID: 22145625 [PubMed – as supplied by publisher]

View full post on pubmed: asthma