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Combined Benefits of a PAR2 Inhibitor and Stratum Corneum Acidification for Murine Atopic Dermatitis

2015; Elsevier BV; Volume: 136; Issue: 2 Linguagem: Inglês

10.1016/j.jid.2015.11.011

1523-1747

Takashi Sakai, Yutaka Hatano, Haruna Matsuda‐Hirose, Wei Zhang, Daisuke Takahashi, Se Kyoo Jeong, Peter M. Elias, Sakuhei Fujiwara,

Contact Dermatitis and Allergies

Atopic dermatitis (AD) is a common disease of heterogeneous etiology resulting from coexistent skin barrier and immunologic abnormalities (Elias and Steinhoff, 2008Elias P.M. Steinhoff M. “Outside-to-inside” (and now back to “outside”) pathogenic mechanisms in atopic dermatitis.J Invest Dermatol. 2008; 128: 1067-1070Abstract Full Text Full Text PDF PubMed Scopus (234) Google Scholar, Elias et al., 2008Elias P.M. Hatano Y. Williams M.L. Basis for the barrier abnormality in atopic dermatitis: outside-inside-outside pathogenic mechanisms.J Allergy Clin Immunol. 2008; 121: 1337-1343Abstract Full Text Full Text PDF PubMed Scopus (369) Google Scholar). Elevation of stratum corneum (SC) pH, a universal accompaniment of barrier defects, as well as inflammatory and environmental factors, such as use of alkaline soaps, are features of AD and are likely to be “drivers” of several pathogenic features of AD, including permeability barrier disturbance and induction of Th2-type inflammation (Ali and Yosipovitch, 2013Ali S.M. Yosipovitch G. Skin pH: from basic science to basic skin care.Acta Derm Venereol. 2013; 93: 261-267Crossref PubMed Scopus (365) Google Scholar, Elias et al., 2008Elias P.M. Hatano Y. Williams M.L. Basis for the barrier abnormality in atopic dermatitis: outside-inside-outside pathogenic mechanisms.J Allergy Clin Immunol. 2008; 121: 1337-1343Abstract Full Text Full Text PDF PubMed Scopus (369) Google Scholar). Accordingly, defective maintenance of SC pH correlated with the emergence and exacerbation of AD-like dermatitis in flaky tail mice (Sakai et al., 2014Sakai T. Hatano Y. Zhang W. Fujiwara S. Defective maintenance of pH of stratum corneum is correlated with preferential emergence and exacerbation of atopic-dermatitis-like dermatitis in flaky-tail mice.J Dermatol Sci. 2014; 74: 222-228Abstract Full Text Full Text PDF PubMed Scopus (17) Google Scholar), whereas maintenance of an acidic pH largely prevented the appearance of AD in repeatedly hapten-challenged mice (Hatano et al., 2009Hatano Y. Man M.Q. Uchida Y. Crumrine D. Scharschmidt T.C. Kim E.G. et al.Maintenance of an acidic stratum corneum prevents emergence of murine atopic dermatitis.J Invest Dermatol. 2009; 129: 1824-1835Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar, Lee et al., 2014Lee H.J. Yoon N.Y. Lee N.R. Jung M. Kim D.H. Choi E.H. Topical acidic cream prevents the development of atopic dermatitis- and asthma-like lesions in murine model.Exp Dermatol. 2014; 23: 736-741Crossref PubMed Scopus (34) Google Scholar). The pathologic consequences of an elevated SC pH are thought to include two divergent pathways: protease-activated receptor-2 (PAR2)-dependent and PAR2-independent mechanisms. PAR2-independent, downstream effects include reduced activity of two key lipid processing enzymes: β-glucocerebrosidase and acidic sphingomyelinase, which exhibit an acidic pH optimum, resulting in delayed maturation of lipid bilayers (Elias et al., 2008Elias P.M. Hatano Y. Williams M.L. Basis for the barrier abnormality in atopic dermatitis: outside-inside-outside pathogenic mechanisms.J Allergy Clin Immunol. 2008; 121: 1337-1343Abstract Full Text Full Text PDF PubMed Scopus (369) Google Scholar). The increase in SC pH also activates a family of serine proteases (i.e., kallikrein) in the outer epidermis, which accelerate the destruction of barrier-related components, such as lipid processing enzymes and corneodesmosomes, while generating the active forms of IL-1α and IL-1β (Elias et al., 2008Elias P.M. Hatano Y. Williams M.L. Basis for the barrier abnormality in atopic dermatitis: outside-inside-outside pathogenic mechanisms.J Allergy Clin Immunol. 2008; 121: 1337-1343Abstract Full Text Full Text PDF PubMed Scopus (369) Google Scholar). In contrast, receptor-dependent activation of PAR2 triggers cutaneous inflammation, especially Th2-type inflammation, via the production of a variety of proinflammatory cytokines and thymic stromal lymphopoietin in epidermal keratinocytes, induction of mast cell degranulation, and itch (Elias et al., 2008Elias P.M. Hatano Y. Williams M.L. Basis for the barrier abnormality in atopic dermatitis: outside-inside-outside pathogenic mechanisms.J Allergy Clin Immunol. 2008; 121: 1337-1343Abstract Full Text Full Text PDF PubMed Scopus (369) Google Scholar, Moormann et al., 2006Moormann C. Artuc M. Pohl E. Varga G. Buddenkotte J. Vergnolle N. et al.Functional characterization and expression analysis of the proteinase-activated receptor-2 in human cutaneous mast cells.J Invest Dermatol. 2006; 126: 746-755Abstract Full Text Full Text PDF PubMed Scopus (101) Google Scholar, Seeliger et al., 2003Seeliger S. Derian C.K. Vergnolle N. Bunnett N.W. Nawroth R. Schmelz M. et al.Proinflammatory role of proteinase-activated receptor-2 in humans and mice during cutaneous inflammation in vivo.FASEB J. 2003; 17: 1871-1885Crossref PubMed Scopus (117) Google Scholar, Steinhoff et al., 2003Steinhoff M. Neisius U. Ikoma A. Fartasch M. Heyer G. Skov P.S. et al.Proteinase-activated receptor-2 mediates itch: a novel pathway for pruritus in human skin.J Neurosci. 2003; 23: 6176-6180Crossref PubMed Google Scholar, Wilson et al., 2013Wilson S.R. Thé L. Batia L.M. Beattie K. Katibah G.E. McClain S.P. et al.The epithelial cell-derived atopic dermatitis cytokine TSLP activates neurons to induce itch.Cell. 2013; 155: 285-295Abstract Full Text Full Text PDF PubMed Scopus (625) Google Scholar). The PAR2 antagonist NPS1577 attenuated the emergence of allergen-induced AD-like dermatitis in flaky tail mice, suggesting the importance of PAR2 signaling in the pathogenesis of AD (Moniaga et al., 2013Moniaga C.S. Jeong S.K. Egawa G. Nakajima S. Hara-Chikuma M. Jeon J.E. et al.Protease activity enhances production of thymic stromal lymphopoietin and basophil accumulation in flaky tail mice.Am J Pathol. 2013; 182: 841-851Abstract Full Text Full Text PDF PubMed Scopus (80) Google Scholar). The therapeutic effect of PAR2 antagonists has not been examined. Maintenance of SC acidity with application of the polyhydroxy acid lactobionic acid (LBA) also mitigated the emergence of hapten-induced AD-like dermatitis in mice (Hatano et al., 2009Hatano Y. Man M.Q. Uchida Y. Crumrine D. Scharschmidt T.C. Kim E.G. et al.Maintenance of an acidic stratum corneum prevents emergence of murine atopic dermatitis.J Invest Dermatol. 2009; 129: 1824-1835Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar, Lee et al., 2014Lee H.J. Yoon N.Y. Lee N.R. Jung M. Kim D.H. Choi E.H. Topical acidic cream prevents the development of atopic dermatitis- and asthma-like lesions in murine model.Exp Dermatol. 2014; 23: 736-741Crossref PubMed Scopus (34) Google Scholar). However, acidification did not exhibit significant therapeutic benefits, presumably because SC pH cannot be fully maintained once the AD-like dermatitis develops (Hatano et al., 2009Hatano Y. Man M.Q. Uchida Y. Crumrine D. Scharschmidt T.C. Kim E.G. et al.Maintenance of an acidic stratum corneum prevents emergence of murine atopic dermatitis.J Invest Dermatol. 2009; 129: 1824-1835Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar). Accordingly, we examined the potential therapeutic benefits of coapplications of the PAR2 antagonist NPS1577 along with LBA on hapten-induced AD-like dermatitis. Specifically, we asked whether cotreatment with a PAR2 antagonist and LBA might be more effective than either approach alone, which could represent a novel therapeutic strategy based on recent knowledge obtained on aberrant SC pH and a PAR2-dependent mechanism in the pathogenesis of AD. Details of the methods of this study are described in the Supplementary Materials and Methods (online). We produced an oxazolone-induced atopic dermatitis-like dermatitis (Ox-AD) model (Hatano et al., 2009Hatano Y. Man M.Q. Uchida Y. Crumrine D. Scharschmidt T.C. Kim E.G. et al.Maintenance of an acidic stratum corneum prevents emergence of murine atopic dermatitis.J Invest Dermatol. 2009; 129: 1824-1835Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar, Hatano et al., 2010Hatano Y. Man M.Q. Uchida Y. Crumrine D. Mauro T.M. Feingold K.R. et al.Murine atopic dermatitis responds to peroxisome proliferator-activated receptors alpha and beta/delta (but not gamma) and liver X receptor activators.J Allergy Clin Immunol. 2010; 125: 160-169Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar, Man et al., 2008Man M.Q. Hatano Y. Lee S.H. Man M. Chang S. Feingold K.R. Characterization of a hapten-induced, murine model with multiple features of atopic dermatitis: structural, immunologic, and biochemical changes following single versus multiple oxazolone challenges.J Invest Dermatol. 2008; 128: 79-86Abstract Full Text Full Text PDF PubMed Scopus (202) Google Scholar) that exhibits apparent dermatitis; elevated transepidermal water loss and SC pH; increased epidermal thickness and dermal infiltration of mast cells; increased mast cell degranulation; and reduced SC hydration (Figure 1, and Supplementary Figures S1 online and S2 online). Although treatment with PAR2 antagonist or LBA alone exhibited therapeutic benefits for some endpoints compared with vehicle control, coapplications of PAR2 antagonist and LBA showed more potent benefits for all of the assessed endpoints compared to PAR2 antagonist or LBA alone, except for mast cell degradation in which PAR2 antagonist or LBA alone and coapplications of PAR2 antagonist and LBA showed equivalent suppressive effects. Treatment with PAR2 antagonist alone showed significant reduction of mast cell degranulation accompanied by moderate reduction of serine protease activity (Figure 2). Treatment with LBA alone failed to maintain SC acidity at the endpoint (Figure 1), consistent with the results of our previous study (Hatano et al., 2009Hatano Y. Man M.Q. Uchida Y. Crumrine D. Scharschmidt T.C. Kim E.G. et al.Maintenance of an acidic stratum corneum prevents emergence of murine atopic dermatitis.J Invest Dermatol. 2009; 129: 1824-1835Abstract Full Text Full Text PDF PubMed Scopus (96) Google Scholar). However, treatment with LBA alone also showed significant reduction of mast cell degradation and serine protease activity, suggesting that transient maintenance of SC acidity might be sufficient or even more potent than PAR2 antagonist alone in reducing serine protease activity under the topical treatment (Figure 2). Meanwhile, the present results showed that the anti–serine protease activity obtained by topical applications of either PAR2 antagonist or LBA alone was not enough to suppress the expression of thymic stromal lymphopoietin, suggesting that more potent anti–serine protease activity and/or other effects might be required for significant reduction of thymic stromal lymphopoietin in murine AD-like dermatitis (Figure 2). Accordingly, because of the failure of maintenance of SC acidity, β-glucocerebrosidase activity was not enhanced by treatment with LBA alone (Figure 2). However, coapplications of PAR2 antagonist and LBA provided additional benefits, including suppression of thymic stromal lymphopoietin expression in parallel with a reduction in serine protease activity and elevation in β-glucocerebrosidase activity (Figure 1, Figure 2, and Supplementary Figures S1 and S2), suggesting not only that coapplication of PAR2 antagonist and LBA could be involved in both PAR2-independent and PAR2-dependent mechanisms, but also that it might be essential to account for both mechanisms to confer significant therapeutic benefits in AD. Meanwhile, the antipruritic effect from inhibiting PAR2 signaling also could be involved in the therapeutic effects, although we could not evaluate quantitatively the degree of itch in this study. This study demonstrates that coapplications of a PAR2 antagonist and the polyhydroxy acid LBA could represent a novel therapeutic strategy that simultaneously addresses the two mechanisms of AD pathogenesis, namely, skin barrier abnormality and allergic inflammation. The study results form the basis for further evaluation of this strategy in other AD animal models and in human AD. All experiments with mice were approved by the Ethics of Animal Experimentation Committee of Oita University. SK Jeong is an employee of NeoPharm Co., Ltd., South Korea. The authors are grateful to Satoko Sato for skilled technical assistance. This study was supported by grants from the Japan Society for the Promotion of Science (No. 26461662 to YH and No. 25860958 to TS). Download .pdf (.75 MB) Help with pdf files Supplementary Data