Pharmacological blockade of adenosine A2A receptors diminishes scarring.
ABSTRACT Adenosine A2A receptor (A(2A)R) stimulation promotes wound healing and is required for the development of fibrosis in murine models of scleroderma and cirrhosis. Nonetheless, the role of A(2A)R in the formation of scars following skin trauma has not been explored. Here, we examined the effect of pharmacological blockade of A(2A)R, with the selective adenosine A(2A)R-antagonist ZM241385 (2.5 mg/ml), in a murine model of scarring that mimics human scarring. We found that application of the selective adenosine A(2A)R antagonist ZM241385 decreased scar size and enhanced the tensile strength of the scar. Within the scar itself, collagen alignment and composition (marked reduction in collagen 3), but not periostin, biglycan, or fibronectin accumulation, was improved by application of ZM241385. Moreover, A(2A)R blockade reduced the number of myofibroblasts and angiogenesis but not macrophage infiltration in the scar. Taken together, our work strongly suggests that pharmacological A(2A)R blockade can be used to diminish scarring while improving the collagen composition and tensile strength of the healed wound.-Perez-Aso, M., Chiriboga, L., Cronstein, B. N. Pharmacological blockade of adenosine A(2A) receptors diminishes scarring.
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ABSTRACT: The nucleoside adenosine is a known regulator of immunity and inflammation that mediates, at least in part, the anti-inflammatory effect of methotrexate, an immunosuppressive agent widely used to treat autoimmune inflammatory diseases. Adenosine A2A receptors play a key role in the inhibition of the inflammatory process besides promoting wound healing. Therefore, we aimed to determine the topical effect of a selective agonist, CGS-21680, on a murine model of skin hyperplasia with a marked inflammatory component. Pretreatment with either CGS-21680 (5 μg per site) or the reference agent dexamethasone (200 μg/site) prevented the epidermal hyperplasia and inflammatory response induced by topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA, 2 nmol/site) for three consecutive days. The histological analysis showed that both CGS-21680 and dexamethasone produced a marked reduction of inflammatory cell infiltrate, which correlated with diminished myeloperoxidase (MPO) activity in skin homogenates. Both treatments reduced the levels of the chemotactic mediators LTB4 and CXCL-1, and the inflammatory cytokine TNF-α, through the suppression of NFκB phosphorylation. The immunohistochemical analysis of the hyperproliferative markers cytokeratin 6 (CK6) and Ki67 revealed that while both agents inhibit the number of proliferating cells in the epidermis, CGS-21680 treatment promoted dermal fibroblasts proliferation. Consistently, increased collagen deposition in dermis was observed in tissue sections from agonist-treated mice. Our results showed that CGS 21680 efficiently prevents phorbol-induced epidermal hyperplasia and inflammation in mice without the deleterious atrophic effect of topical corticosteroids.This article is protected by copyright. All rights reserved.Experimental Dermatology 05/2014; · 3.58 Impact Factor
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ABSTRACT: Inflammation is the physiological response to tissue injury caused by pathogens or trauma. Nevertheless, inflammation should be resolved in a timely manner, resulting in elimination of the inflammatory cells and mediators from the injured tissue, to avoid its deleterious consequences. Uncontrolled inflammation can lead to inflammatory, autoimmune and cancerous disorders that are the result of improper resolution. The healing of the injured tissue during the termination of inflammation must also be tightly controlled since excessive tissue repair can lead to fibrosis and scarring of the affected organ. In the last 3 decades it has been revealed that the resolution of inflammation is tightly orchestrated by specific cells, protein and lipid mediators that are produced at proper timing and distinct locations. The bioactivityof these anti-inflammatory, pro-resolving and immunoregulatory agents results in clearance of the tissue from inflammatory leukocytes and their products, and the return of homeostatic tissue architecture and function. Here we will survey the current endogenous mechanisms governing the resolution of inflammation and directing it towards injury healing and halting of acquired immune responses while preventing excessive tissue repair and fibrosis. We focus on the role played by apoptotic polymorphonuclear (PMN) cells, 15-lipoxygenase (LO)-derived lipid mediators and TGFβin this macrophage-governed decision-makingprocess and suggest new modes of action for fibrosis prevention and return to homeostasis. Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.The Journal of Pathology 09/2012; · 7.59 Impact Factor
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ABSTRACT: Chronic musculoskeletal pain involves connective tissue remodeling triggered by inflammatory mediators, such as bradykinin. Fibroblast cells signaling involve changes in intracellular Ca2+ ([Ca2+]i). ATP has been related to connective tissue mechanotransduction, remodeling and chronic inflammatory pain, via P2 purinoceptors activation. Here, we investigated the involvement of ATP in bradykinin-induced Ca2+ signals in human subcutaneous fibroblasts. Bradykinin, via B2 receptors, caused an abrupt rise in [Ca2+]i to a peak that declined to a plateau, which concentration remained constant until washout. The plateau phase was absent in Ca2+-free medium; [Ca2+]i signal was substantially reduced after depleting intracellular Ca2+ stores with thapsigargin. Extracellular ATP inactivation with apyrase decreased the [Ca2+]i plateau. Human subcutaneous fibroblasts respond to bradykinin by releasing ATP via connexin and pannexin hemichannels, since blockade of connexins, with 2-octanol or carbenoxolone, and pannexin-1, with 10Panx, attenuated bradykinin-induced [Ca2+]i plateau, whereas inhibitors of vesicular exocytosis, such as brefeldin A and bafilomycin A1, were inactive. The kinetics of extracellular ATP catabolism favors ADP accumulation in human fibroblast cultures. Inhibition of ectonucleotidase activity and, thus, ADP formation from released ATP with POM-1 or by Mg2+ removal from media reduced bradykinin-induced [Ca2+]i plateau. Selective blockade of the ADP-sensitive P2Y12 receptor with AR-C66096 attenuated bradykinin [Ca2+]i plateau, whereas the P2Y1 and P2Y13 receptor antagonists, respectively MRS 2179 and MRS 2211, were inactive. Human fibroblasts exhibited immunoreactivity against connexin-43, pannexin-1 and P2Y12 receptor. Bradykinin induces ATP release from human subcutaneous fibroblasts via connexin and pannexin-1-containing hemichannels leading to [Ca2+]i mobilization through the cooperation of B2 and P2Y12 receptors.Cell Communication and Signaling 09/2013; 11(1):70. · 5.09 Impact Factor