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Ultraviolet A (320–400 nm) Modulation of Ultraviolet B (290–320 nm)-Induced Immune Suppression Is Mediated by Carbon Monoxide

2005; Elsevier BV; Volume: 124; Issue: 3 Linguagem: Inglês

10.1111/j.0022-202x.2005.23614.x

1523-1747

Munif Allanson, Vivienne E. Reeve,

Thermal Regulation in Medicine

Accumulating evidence suggests that suberythemogenic ultraviolet A (UVA) (320–400 nm) exposure protects against the immunosuppressive effect of ultraviolet B (290–320 nm) radiation or its epidermal photoproduct, cis-urocanic acid (cis-UCA). In skin, UVA photoimmunoprotection is mediated by the inducible antioxidant stress enzyme, heme oxygenase-1 (HO-1), which degrades heme into carbon monoxide (CO), iron, and biliverdin (reduced to bilirubin), and is important for cell survival under conditions of oxidative stress. The identity of the HO enzymatic product(s) that provide the immunoprotection is unknown. Here we examine the potential of CO to fulfill this role in hairless mouse skin, utilizing a novel CO-releasing molecule (CO-RM) to deliver CO to the skin topically. The CO-RM released CO gradually from the lotion vehicle during 3 h following its preparation, and between 50 and 500 μM, concentration-dependently protected mice against the suppression of contact hypersensitivity by either solar-simulated UV radiation (SSUVR) or cis-UCA, whereas aged CO-depleted CO-RM was inactive. Thus, the CO-RM treatment mimicked UVA-photoimmunoprotection, and identified HO-released CO as the protective mediator, providing evidence that the murine cutaneous immune system is modulated by this gaseous messenger. Preliminary evidence for involvement of guanylyl cyclase was obtained by treatment of the mouse with its specific inhibitor 1H-(1,2,4)oxadiazolo-(4,3-1)quinoxaline-1-one, which abrogated UVA photoimmunoprotection. Accumulating evidence suggests that suberythemogenic ultraviolet A (UVA) (320–400 nm) exposure protects against the immunosuppressive effect of ultraviolet B (290–320 nm) radiation or its epidermal photoproduct, cis-urocanic acid (cis-UCA). In skin, UVA photoimmunoprotection is mediated by the inducible antioxidant stress enzyme, heme oxygenase-1 (HO-1), which degrades heme into carbon monoxide (CO), iron, and biliverdin (reduced to bilirubin), and is important for cell survival under conditions of oxidative stress. The identity of the HO enzymatic product(s) that provide the immunoprotection is unknown. Here we examine the potential of CO to fulfill this role in hairless mouse skin, utilizing a novel CO-releasing molecule (CO-RM) to deliver CO to the skin topically. The CO-RM released CO gradually from the lotion vehicle during 3 h following its preparation, and between 50 and 500 μM, concentration-dependently protected mice against the suppression of contact hypersensitivity by either solar-simulated UV radiation (SSUVR) or cis-UCA, whereas aged CO-depleted CO-RM was inactive. Thus, the CO-RM treatment mimicked UVA-photoimmunoprotection, and identified HO-released CO as the protective mediator, providing evidence that the murine cutaneous immune system is modulated by this gaseous messenger. Preliminary evidence for involvement of guanylyl cyclase was obtained by treatment of the mouse with its specific inhibitor 1H-(1,2,4)oxadiazolo-(4,3-1)quinoxaline-1-one, which abrogated UVA photoimmunoprotection. contact hypersensitivity cis-urocanic acid carbon monoxide carbon monoxide-releasing molecule dimethyl sulfoxide heme oxygenase mitogen-activated protein kinase 1H-(1,2,4)oxadiazolo-(4,3-1)quinoxaline- 1-one ruthenium 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl-5-4-(4-pyridyl) 1H-imidazole Sn protoporphyrin-IX solar-simulated ultraviolet radiation ultraviolet A (320–400 nm) ultraviolet B (290–320 nm) The immunological outcome of ultraviolet A (UVA) (320–400 nm) exposure of the skin remains controversial. Evidence exists for its immunosuppressive action in mice (Bestak and Halliday, 1996Bestak R. Halliday G.M. Chronic low-dose UVA irradiation induced local suppression of contact hypersensitivity, Langerhans cell depletion and suppressor cell activation in C3H/HeJ mice.Photochem Photobiol. 1996; 64: 969-974Crossref PubMed Scopus (67) Google Scholar; Iwai et al., 1999Iwai I. Hatao M. Naganuma M. Kumano Y. Ichihashi M. UVA-induced immune suppression through an oxidative pathway.J Invest Dermatol. 1999; 112: 12-18Google Scholar; Ngheim et al., 2001Ngheim D.X. Kazimi N. Clydesdale G. Ananthaswamy H. Kripke M.L. Ullrich S.E. Ultraviolet A radiation suppresses an established immune response: Implications for sunscreen design.J Invest Dermatol. 2001; 117: 1193-1199Crossref PubMed Scopus (96) Google Scholar) and in humans (Damian et al., 1999Damian D.L. Barnetson R.St.C. Halliday G.M. Low-dose UVA and UVB have different time courses for suppression of contact hypersensitivity to a recall antigen in humans.J Invest Dermatol. 1999; 112: 939-944Crossref PubMed Scopus (92) Google Scholar; Dumay et al., 2001Dumay O. Karam A. Vian L. et al.Ultraviolet A1 exposure of human skin results in Langerhans cell depletion and reduction of epidermal antigen-presenting cell function: partial protection by a broad spectrum sunscreen.Br J Dermatol. 2001; 144: 1161-1168Crossref PubMed Scopus (77) Google Scholar), but also for a lack of effect in mice (Aubin et al., 1991Aubin F. Dall'Acqua F. Kripke M.L. Local suppression of contact hypersensitivity in mice by a new bifunctional psoralen, 4,4′5′-trimethylazapsoralen, and UVA radiation.J Invest Dermatol. 1991; 97: 50-54Abstract Full Text PDF PubMed Google Scholar; Reeve et al., 1998Reeve V.E. Bosnic M. Boehm-Wilcox C. Nishimura N. Ley R.D. Ultraviolet A radiation (320–400 nm) protects hairless mice from immunosuppression induced by ultraviolet B radiation (280–320 nm) or cis-urocanic acid.Int Arch Allergy Immunol. 1998; 115: 316-322Crossref PubMed Scopus (89) Google Scholar) and humans (Skov et al., 1997Skov L. Hansen H. Barker J.N.W.N. Simon J.C. Baadsgaard O. Contrasting effects of ultraviolet-A and ultraviolet-B exposure on induction of contact hypersensitivity in human skin.Clin Exp Immunol. 1997; 107: 585-588Crossref PubMed Scopus (55) Google Scholar). In addition to this confusion, a number of studies in mice indicate that the UVA waveband, when administered at environmentally relevant suberythemogenic doses, is itself immunologically inert but can provide protection against the immunosuppressive effects of ultraviolet B (UVB) (290–320 nm) irradiation, or of the epidermal UVB photoproduct, cis-urocanic acid (cis-UCA) (Reeve et al., 1998Reeve V.E. Bosnic M. Boehm-Wilcox C. Nishimura N. Ley R.D. Ultraviolet A radiation (320–400 nm) protects hairless mice from immunosuppression induced by ultraviolet B radiation (280–320 nm) or cis-urocanic acid.Int Arch Allergy Immunol. 1998; 115: 316-322Crossref PubMed Scopus (89) Google Scholar; Garssen et al., 2001Garssen J. de Gruijl F. Mol D. deKlerk A. Roholl P. van Loveren H. UVA exposure affects UVB and cis-urocanic acid-induced systemic suppression of immune responses in Listeria monocytogenes-infected Balb/c mice.Photochem Photobiol. 2001; 73: 432-438Crossref PubMed Scopus (34) Google Scholar; Khaskhely et al., 2001Khaskhely N.M. Maruno M. Takamiyagi A. et al.Pre-exposure withy low-dose UVA suppresses lesion development and enhances Th1 response in BALB/c mice infected with Leishmania amazonensis.J Dermatol Sci. 2001; 26: 217-232Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar). There is now supporting evidence for this phenomenon also in humans (Skov et al., 2000Skov L. Villadsen B. Ersboll B.J. Simon J.C. Barker J. Baadsgaard O. Long-wave UVA offers partial protection against UVB-induced immune suppression in human skin.Acta Pathologica Microbiologica et Immunologica Scandinavica. 2000; 108: 825-830Crossref Scopus (16) Google Scholar). Subsequently, it has been demonstrated (Reeve and Tyrrell, 1999Reeve V.E. Tyrrell R.M. Heme oxygenase induction mediates the photoimmunoprotective activity of UVA radiation in the mouse.Proc Natl Acad Sci USA. 1999; 96: 9317-9321Crossref PubMed Scopus (98) Google Scholar) that the UVA photoimmunoprotection in the mouse is mediated by increased levels of the stress enzyme heme oxygenase (HO). HO is a redox-regulated enzyme catalyzing the degradation of heme, releasing biliverdin (which is rapidly converted to bilirubin by the ubiquitous biliverdin reductase), free Fe and the gaseous molecule, carbon monoxide (CO) (Maines, 1997Maines M.D. The heme oxygenase system: A regulator of second messenger gases.Ann Rev Pharmacol Toxicol. 1997; 37: 517-554Crossref PubMed Scopus (2131) Google Scholar). Two isoforms of HO have been found in the skin, constitutive HO-2 and inducible HO-1, which responds to a variety of oxidative stressors, including UVA radiation. In mouse skin, HO-1 mRNA and protein were induced in response to suberythemogenic UVA exposure, but were otherwise not detectable and did not respond to UVB irradiation (Allanson and Reeve, 2004Allanson M. Reeve V.E. Immunoprotective UVA (320–400 nm) irradiation upregulates heme oxygenase-1 in the dermis and epidermis of hairless mouse skin.J Invest Dermatol. 2004; 122: 1030-1036Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar). Both HO isoforms provide the same enzymological activity, and can be effectively inhibited in the mouse by the injection of the substrate antagonist Sn protoporphyrin-IX (SnPP), but the immunological properties of HO appear to be because of the induced HO-1 only (Reeve and Tyrrell, 1999Reeve V.E. Tyrrell R.M. Heme oxygenase induction mediates the photoimmunoprotective activity of UVA radiation in the mouse.Proc Natl Acad Sci USA. 1999; 96: 9317-9321Crossref PubMed Scopus (98) Google Scholar) because SnPP did not alter the normal immune response in non-UV-irradiated mice. How the products of HO enzyme activity might modulate immune function has remained unclear. Bilirubin has well-described antioxidant potential (Stocker et al., 1987Stocker R. Glazer R.N. Ames B.N. Antioxidant activity of albumin-bound bilirubin.Proc Natl Acad Sci USA. 1987; 84: 5918-5922Crossref PubMed Scopus (637) Google Scholar) and might be immunoprotective like other identified antioxidants such as vitamin C and vitamin E (Gensler and Magdaleno, 1991Gensler H.L. Magdaleno M. Topical vitamin E inhibition of immunosuppression and tumorigenesis induced by ultraviolet irradiation.Nutr Cancer. 1991; 15: 97-106Crossref PubMed Scopus (162) Google Scholar; Nakamura et al., 1997Nakamura T. Pinnell S.R. Darr D. Kurimoto I. Itami S. Yoshikawa K. Streilein J.W. Vitamin C abrogates the deleterious effects of UVB radiation on cutaneous immunity by a mechanism that does not depend on TNF-alpha.J Invest Dermatol. 1997; 109: 20-24Crossref PubMed Scopus (84) Google Scholar); free Fe poses an oxidative hazard, but is rapidly sequestered by ferritin (Vile and Tyrrell, 1993Vile G.F. Tyrrell R.M. Oxidative stress resulting from ultraviolet A irradiation of human skin fibroblasts leads to a heme oxygenase dependent increase in ferritin.J Biol Chem. 1993; 268: 14678-14681Abstract Full Text PDF PubMed Google Scholar), whereas CO is now recognized as a potent signalling molecule that has anti-inflammatory (Otterbein et al., 2000Otterbein L.E. Bach F.H. Alam J. et al.Carbon monoxide has anti-inflammatory effects involving the mitogen activated protein kinase pathway.Nat Med. 2000; 6: 422-428Crossref PubMed Scopus (1728) Google Scholar), anti-apoptotic (Brouard et al., 2000Brouard S. Otterbein L.E. Anrather J. Tobiasch E. Bach F.H. Choi A.M. Soares M.P. Carbon monoxide generated by heme oxygenase 1 suppresses endothelial cell apoptosis.J Exp Med. 2000; 192: 1015-1026Crossref PubMed Scopus (831) Google Scholar), anti-proliferative (Peyton et al., 2002Peyton K.J. Reyna S.V. Chapma G.B. et al.Heme oxygenase-1-derived carbon monoxide is an autocrine inhibitor of vascular smooth muscle cell growth.Blood. 2002; 99: 4443-4448Crossref PubMed Scopus (136) Google Scholar; Song et al., 2002Song R. Mahidhara R.S. Liu F. Ning W. Otterbein L.E. Choi A.M. Carbon monoxide inhibits airway smooth muscle cell proliferation via mitogen-activated protein kinase pathway.Am J Respir Cell Mol Biol. 2002; 27: 603-610Crossref PubMed Scopus (107) Google Scholar; Durante, 2003Durante W. Heme oxygenase-1 in growth control and its clinical application to vascular disease.J Cell Physiol. 2003; 95: 373-382Crossref Scopus (148) Google Scholar), and immune modulating (Van Uffelen et al., 1996Van Uffelen B.E. de Koster B.M. Van Steveninck J. Elferink J.G. Carbon monoxide enhances human neutrphil migration in a cyclic GMP-dependent way.Biochem Biophys Res Comm. 1996; 226: 21-26Crossref PubMed Scopus (41) Google Scholar; DiBello et al., 1998DiBello M.G. Berni L. Gai P. et al.A regulatory role for carbon monoxide in mast cell function.Inflam Res. 1998; 47: S7-S8Crossref PubMed Google Scholar; Ndisang et al., 1999Ndisang J.F. Gai P. Berni L. Mirabella C. Baronti R. Mannaioni P.F. Masini E. Modulation of the immunological response of guinea pig mast cells by carbon monoxide.Immunopharmacology. 1999; 43: 65-73Crossref PubMed Scopus (39) Google Scholar) properties. In this study, we examine the possible role of CO in mediating the UVA protective effect against immunosuppression caused by solar-simulated UV radiation (SSUVR) or its cutaneous photoproduct, cis-UCA. Mice were treated topically with a unique CO-releasing molecule (CO-RM), and its effect on immune function that was compromised by SSUVR or cis-UCA treatment was measured by the contact hypersensitivity (CHS) reaction. In addition, specific inhibitors of the two possible known targets for endogenously produced CO in other tissue systems, soluble guanylyl cyclase and the p38 of mitogen-activated protein kinase (MAPK), were used in the mouse to help characterize the cutaneous CO-dependent pathway. A complete color change of the CO-RM in dimethyl sulfoxide (DMSO) solution, from yellow to colorless, occurred gradually within 60 min in open air at room temperature (Figure 1). We surmised that CO may therefore be released slowly from the base lotion also, and be available for a period after topical application for delivery into the skin layers, perhaps including the dermis, to mediate biological effects. In sealed or closed containers, the color change of the CO-RM/DMSO solution was observed to take much longer (not shown). The effect of the lotion emulsion on the release of CO from the CO-RM was not tested, but the lotion in the applicator syringe barrel, in which air was excluded, remained yellow during the treatments, and converted to white only when discarded into air contact after daily use. Lotions containing increasing concentrations of either fresh or aged CO-RM were tested for possible immunomodulatory effects from topical application (Figure 2). Fresh CO-RM lotions were not significantly immunosuppressive. The highest tested concentration of the aged CO-RM lotions, 500 μM, did reveal a slight but significant suppression of CHS (p=0.017 by ANOVA), but the Tukey test showed no significant difference; therefore, the biological relevance is uncertain. Irradiation with SSUVR resulted in 32% suppression of CHS (Figure 3). Treatment with 500 μM CO-RM lotion did not significantly affect CHS, but markedly reduced the SSUVR-induced immunosuppression to 15% suppression; p=0.003. In mice in which HO enzyme activity was inhibited by injection with SnPP, the SSUVR was similarly immunosuppressive (48% suppression) as without SnPP treatment (p=0.102). Application of 500 μM CO-RM again effectively (p<0.0001) reduced the SSUVR suppression to 18%, similar to the protection without SnPP inhibition, indicating that the protective effect was because of the exogenous CO-RM and had no significant contribution from endogenously produced CO. The aged CO-RM lotion appeared to protect slightly from SSUVR suppression of CHS, but this was not statistically significant. Consistent with the responses to SSUVR, the topical application of cis-UCA resulted in 23% suppression of CHS (Figure 4; p=0.028), and this was abrogated by 500 μM CO-RM lotion (p=0.001). In the presence of SnPP the suppression by cis-UCA (31% suppression) was not significantly different, and again the suppression was abrogated by 500 μM CO-RM. The protection by the CO-RM against cis-UCA was thus more complete than against SSUVR, suggesting that other contributing mediators of photoimmunosuppression, such as prostaglandins, may be less sensitive to the CO-dependent pathways. This is consistent with the superior protection by UVA radiation against cis-UCA compared with UVB-induced suppression of CHS that we have previously observed (Reeve and Tyrrell, 1999Reeve V.E. Tyrrell R.M. Heme oxygenase induction mediates the photoimmunoprotective activity of UVA radiation in the mouse.Proc Natl Acad Sci USA. 1999; 96: 9317-9321Crossref PubMed Scopus (98) Google Scholar). Thus the results show that the immunosuppressive effects of SSUVR or its immunosuppressive photoproduct, cis-UCA, were strongly inhibited by the presence of the exogenous source of CO, independent of endogenous HO activity, and that the CO-RM treatment mimicked the immunoprotective role of UVA-induced HO activity in the skin. The topical application of 50 μM CO-RM contributed no significant protection (42% suppression of CHS) against cis-UCA-induced immunosuppression (49% suppression). A clear significant dose response could be seen, however, with 125, 250, and 500 μM CO-RM (Figure 5), as the degree of immunosuppression reduced from 49% to 27%, 24% and 14%, respectively (p=0.019, 0.021, p<0.0001, respectively) and the protective effect by 500 μM CO-RM restored the CHS reaction to a level not significantly different from the control level. Topical application of the selective guanylyl cyclase inhibitor 1H-(1,2,4)oxadiazolo-(4,3-1)quinoxaline-1-one (ODQ) did not alter the CHS response. The 52% suppression of CHS induced by SSUVR was reduced to only 20% suppression by UVA radiation (Figure 6). In the presence of ODQ, however, this immune protection was significantly inhibited, and the CHS response remained suppressed by 44% (p 400 μM, although only after prolonged 24 h exposure (Motterlini et al., 2002Motterlini R. Clark J.E. Foresti R. Sarathchandra P. Mann B.E. Green C.J. Carbon monoxide-releasing molecules: Characterization of biochemical and vascular activities.Circ Res. 2