IL-22 Is Required for Imiquimod-Induced Psoriasiform Skin Inflammation in Mice Astrid B. Van Belle, Magali de Heusch, Muriel M. Lemaire, Emilie Hendrickx, Guy Warnier, Kyri This information is current as Dunussi-Joannopoulos, Lynette A. Fouser, Jean-Christophe of September 29, 2021. Renauld and Laure Dumoutier J Immunol published online 30 November 2011 http://www.jimmunol.org/content/early/2011/11/30/jimmun ol.1102224 Downloaded from Why The JI? Submit online. http://www.jimmunol.org/ • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average by guest on September 29, 2021 Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2011 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. Published November 30, 2011, doi:10.4049/jimmunol.1102224 The Journal of Immunology IL-22 Is Required for Imiquimod-Induced Psoriasiform Skin Inflammation in Mice Astrid B. Van Belle,*,† Magali de Heusch,*,† Muriel M. Lemaire,*,† Emilie Hendrickx,*,† Guy Warnier,*,† Kyri Dunussi-Joannopoulos,‡ Lynette A. Fouser,‡ Jean-Christophe Renauld,*,†,1 and Laure Dumoutier*,†,1 Psoriasis is a common chronic autoimmune skin disease of unknown cause that involves dysregulated interplay between immune cells and keratinocytes. IL-22 is a cytokine produced by the TH1, TH17, and TH22 subsets that are functionally implicated in the psoriatic pathology. We assessed the role of IL-22 in a mouse model where psoriasiform skin inflammation is triggered by topical application of the TLR7/8 agonist imiquimod. At the macroscopic level, scaly skin lesions induced by daily applications of imiqui- mod in wild-type mice were almost totally absent in IL-22–deficient mice or in mice treated with a blocking anti–IL-22 Ab. At the microscopic level, IL-22–deficient mice showed a dramatic decrease in the development of pustules and a partial decrease in Downloaded from acanthosis. At the molecular level, the absence or inhibition of IL-22 strongly decreased the expression of chemotactic factors such as CCL3 and CXCL3 and of biomarkers such as S100A8, S100A7, and keratin 14, which reflect the antimicrobial and hyper- proliferative responses of keratinocytes. IL-22 also played a major role in neutrophil infiltration after imiquimod treatment. IL-23 was required for IL-22 production, and gd TCR lymphocytes represented the major source of IL-22 in lymph nodes from imiquimod-treated mice. However, T cells were not absolutely required for IL-22 production because imiquimod-induced IL- 22 expression in the skin is still preserved in Rag22/2 mice. Taken together, our data show that IL-22 is required for psoriasis-like http://www.jimmunol.org/ lesions in the mouse imiquimod model and is produced by both T cells and innate immune cells. The Journal of Immunology, 2012, 188: 000–000. L-22 is a cytokine related to IL-10 for its structure and to IL- eration of keratinocytes and induced hyperplasia of reconstituted 17 for its cellular pattern of production (1). This cytokine can epidermis (4). I hardly be classified as a pro- or anti-inflammatory cytokine. These biological activities are expected to be beneficial during For instance, analysis of IL-22–deficient mice indicated that it wound healing and infectious processes but might contribute plays a pathogenic role in an arthritis model (2) while being to skin lesions of patients with psoriasis disease, one of the most by guest on September 29, 2021 protective in several colitis models (3). The main physiological common autoimmune-mediated chronic inflammatory skin dis- role of IL-22 appears to be related to wound healing and innate orders that affects ∼2% of the general population (10). Increased antimicrobial responses, because its receptor is mainly expressed levels of Th17 cells and their associated cytokines including IL- by nonhematopoietic cells at body barriers including epithelial 23, IL-17, and IL-22 have been found in human psoriatic skin (6, cells of the lung and gastrointestinal tract and keratinocytes (1). 11, 12). Elevated IL-22 concentrations were measured in plasma In vitro studies showed that IL-22 activates STAT3 (4–6) and from patients and IL-22 production correlated positively with upregulates the expression of proinflammatory and antimicrobial severity of the disease and negatively with response to therapy molecules such as S100A7, S100A8, S100A9, and b-defensins in suggesting a significant role of this cytokine in psoriasis (5, 7, 13). human keratinocytes (4–7), alone or in synergy with IL-17 or TNF T lymphocytes appeared to represent a major source of IL-22 in (8, 9). IL-22 also regulates the cellular differentiation and prolif- skin lesions (7) and treatment with cyclosporine A downregulated both IL-17 and IL-22 expression in those patients (14). *Ludwig Institute for Cancer Research, B-1200 Brussels, Belgium; †de Duve Insti- Psoriasis is not observed in animals other than humans, but tute, Universite´ catholique de Louvain, B-1200 Brussels, Belgium; and ‡Inflammation a large number of mouse models have been set up to mimic at least and Autoimmunity Research Unit, Pfizer BioTherapeutics Research and Development, some aspects of the human disease (15, 16). Psoriasis lesions Cambridge, MA 02140 1 are characterized by several histological features including 1) a J.-C.R. and L.D. share senior coauthorship. thickened epidermis caused by keratinocyte proliferation that is Received for publication August 4, 2011. Accepted for publication November 2, called acanthosis, 2) retention of nuclei in the stratum corneum 2011. (parakeratosis) that arises from an aberrant differentiation of This work was supported in part by the Belgian Programme on Interuniversity Poles of Attraction initiated by the Belgian State, Prime Minister’s Office, Science Policy keratinocytes, and 3) inflammatory cell infiltrates in the epidermis Programming, and by the Actions de Recherche Concerte´es of the Communaute´ and dermis (17, 18). IL-22–transgenic mice die soon after birth Franc¸aise de Belgique. L.D. is a Research Associate and A.B.V.B. is a Research with acanthosis and hyperkeratosis that are reminiscent of such Fellow with the Fonds National de la Recherche Scientifique, Belgium. psoriatic lesions (19). Acanthosis can also be induced in wild-type Address correspondence and reprint request to Dr. Jean-Christophe Renauld and Laure Dumoutier, Ludwig Institute for Cancer Research, Avenue Hippocrate 74, 1200 mice by intradermal injection of rIL-23, and this effect is partially Brussels, Belgium. E-mail addresses: [email protected] and laure.dumoutier@bru. abolished in IL-22–deficient mice (20). The role of IL-22 is also licr.org supported by a graft versus host disease (GVHD) mouse model Abbreviations used in this article: GVHD, graft versus host disease; Ngp, neutro- that is based on the transfer of CD4+CD45RBhi T lymphocytes, philic granule protein; qPCR, quantitative PCR. depleted of regulatory T cells, into immunodeficient mice. The Copyright Ó 2011 by The American Association of Immunologists, Inc. 0022-1767/11/$16.00 recipient mice develop acanthosis, elevated levels of antimicrobial www.jimmunol.org/cgi/doi/10.4049/jimmunol.1102224 2 ROLE OF IL-22 IN IMIQUIMOD-INDUCED PSORIASIS peptides and inflammatory infiltrates that can be abolished by Diff-Quick solutions (Medion Diagnostics Ag, Du¨dingen, Switzerland). anti–IL-22 Abs (21). Interestingly, this same GVHD mouse model Percentages of neutrophils were counted on five different areas (with ∼200 can also result in colitis that is exacerbated by IL-22 inhibition, in cells) for each cytospin. Cells from lymph nodes were extracted by mechanical disruption and contrast to the effect in the skin, demonstrating the dual activity resuspended in Iscove Dulbecco medium. For intracellular staining, cells of this cytokine in inflammation (3). were incubated at 37˚C in the presence of GolgiStop solution (BD Bio- More recently, topical treatment with imiquimod, a ligand for sciences) and IL-23 (10 ng/ml) and IL-2 (400 U/ml). After 4 h, cells were TLR7 and TLR8 was reported as a novel mouse model for stained with Abs specific for cell surface Ags at 4˚C. Cells were then fixed, permeabilized, and processed for intracellular staining using the Cytofix/ psoriasis-like skin inflammation, inducing acanthosis, parakeratosis, Cytoperm Plus Kit (BD Biosciences). The mAbs specific to murine Ags and a mixed inflammatory infiltrate (22). Imiquimod is used in used in this study were MH22B2 (anti–IL-22) and MM17F3 (anti–IL- humans for topical treatment of genital and perianal warts caused 17A), which were produced in our laboratory (32), whereas PC61 (anti- by human papillomavirus (23), actinic keratosis, and superficial CD25), 17A2 (anti-CD3), GK1.5 (anti-CD4), H57-597 (anti-TCRb), and basal cell carcinoma (24, 25). Clinical application of imiquimod GL3 (anti-TCRgd) were purchased from BioLegend. can also induce psoriasis or exacerbate the disease in patients T lymphocyte adoptive transfer with a well-controlled psoriasis (26–30). Spleen cell suspensions from BALB/c mice were prepared by mechanical Recently, a pivotal role of the IL-23/IL-17 axis was demonstrated disruption and RBC lysis. The AutoMACS system from Miltenyi Biotec in the mouse skin inflammation induced by imiquimod (22). In this (Bergisch Gladbach, Germany) was used to isolate T lymphocytes, based on study, we show that IL-22–deficient mice are almost totally pro- CD5 expression following the manufacturer’s instructions.