Ex vivo culture of lesional psoriasis skin for pharmacological testing

Background: Psoriasis is a chronic, inflammatory skin disorder resulting from a complex interplay between immune and skin cells via release of soluble mediators. While a lot is known about the molecular mechanisms behind psoriasis pathogenesis, there is still a need for preclinical research models that accuratelyreplicate the disease. Objective: This study aimed to develop and characterize ex vivo culture of psoriasis skin as a model for pharmacological testing, where the immunological events of psoriasis can be followed. Methods: Full thickness punch biopsies of lesional psoriasis skin were cultured in submerged conditions up to 144 h followingin situ T cell stimulation with rhIL-23 and anti-CD3 and anti-CD28 antibodies. The Tcell mediated skin inflammation was assessed by gene and protein l analysis for a panel of inflammatory mediators. Tissue integrity and morphology were evaluated by histological analysis. Results: T cell stimulation resulted in functional and psoriasis specificin situ activation of T cells. The expression levels of most of the proinflammatory mediators related to both immune and skin cells were comparable to these in freshly isolated tissue at 48 and 96 h of culture. Tissue integrity and morphology were sustained up to 96 h. Treatment with a corticosteroid reduced the expression of several proinflammatory cytokines and chemokines, whereas anti-IL-17A antibody treatment reduced the expression of the IL-17A downstream markers IL-8 and DEFB4. Conclusion: By preserving keyimmunopathological mechanisms of psoriasis, ex vivo culture of psoriasis skin can be used for the investigation of inflammatory processes of psoriasis and for preclinical drug discovery research

Epigenetic control of <em>IL-23</em> expression in keratinocytes is important for chronic skin inflammation

Although IL-23 is expressed by psoriatic keratinocytes as well as immune cells, only the immune cell derived IL-23 is thought to be important for the development of psoriasis. Here the authors provide evidence that keratinocyte-produced IL-23 is sufficient to cause a chronic skin inflammation

Tralokinumab Effectively Disrupts the IL-13/IL-13Rα1/IL-4Rα Signaling Complex but Not the IL-13/IL-13Rα2 Complex

Tralokinumab, a fully human mAb specifically targeting the IL-13 cytokine, has demonstrated clinical efficacy and safety in patients with moderate-to-severe atopic dermatitis. Tralokinumab binds IL-13 with high affinity, which prevents the interaction of IL-13 with IL-13Rα1 and subsequent signaling. Similarly, tralokinumab-bound IL-13 cannot bind to IL-13Rα2, a proposed decoy receptor that is reported to bind IL-13 with extraordinarily high affinity. It has however not been fully elucidated to what extent tralokinumab interferes with the endogenous regulation of IL-13 through IL-13Rα2. In this mechanistic study, we used biophysical, biochemical, and cellular assays to investigate the effect of tralokinumab on the interaction between IL-13 and IL-13Rα1 and IL-13Rα2, respectively, as well as the effects on IL-13Rα2–mediated IL-13 internalization. We demonstrate that IL-13Rα2 binds IL-13 with exceptionally high affinity and that tralokinumab is unable to displace IL-13 from IL-13Rα2. In contrast to this, tralokinumab is able to disrupt the IL-13/IL-13Rα1 and IL-13Rα1/IL-13/IL-4Rα complex. Furthermore, we demonstrate that whereas the IL-13/tralokinumab complex is unable to bind IL-13Rα2, any IL-13 that is not bound by tralokinumab (i.e., free IL-13) can be bound by IL-13Rα2 and subsequently internalized, regardless of the presence of tralokinumab. In summary, our study indicates that tralokinumab does not interfere with endogenous IL-13Rα2–mediated regulation of free IL-13

IL-23-Mediated Epidermal Hyperplasia Is Dependent on IL-6

Psoriasis is a chronic inflammatory skin disease primarily driven by Th17 cells. IL-23 facilitates the differentiation and induces complete maturation of Th17 cells. Lesional psoriatic skin has increased levels of IL-23 and recent studies show that intradermal injections of IL-23 induce a psoriasis-like skin phenotype in mice. We have now characterized the IL-23-induced skin inflammation in mice at the molecular level and found a significant correlation with the gene expression profile from lesional psoriatic skin. As observed in psoriasis, the pathogenesis of the IL-23-induced skin inflammation in mice is driven by Th17 cells. We demonstrate a dramatic upregulation of IL-6 mRNA and protein after intradermal injections of IL-23 in mice. Using IL-6−/− mice we show that IL-6 is essential for development of the IL-23-elicited responses. Despite producing high levels of IL-22, IL-6−/− mice were unable to express the high-affinity IL-22 receptor chain and produced minimal IL-17A in response to intradermal injections of IL-23. In conclusion, we provide evidence for the critical role played by IL-6 in IL-23-induced skin inflammation and show that IL-6 is required for expression of IL-22R1A

Humanized mouse model of skin inflammation is characterized by disturbed keratinocyte differentiation and influx of IL-17A producing T cells

Contains fulltext : 108173.pdf (publisher's version ) (Open Access)Humanized mouse models offer a challenging possibility to study human cell function in vivo. In the huPBL-SCID-huSkin allograft model human skin is transplanted onto immunodeficient mice and allowed to heal. Thereafter allogeneic human peripheral blood mononuclear cells are infused intra peritoneally to induce T cell mediated inflammation and microvessel destruction of the human skin. This model has great potential for in vivo study of human immune cells in (skin) inflammatory processes and for preclinical screening of systemically administered immunomodulating agents. Here we studied the inflammatory skin response of human keratinocytes and human T cells and the concomitant systemic human T cell response.As new findings in the inflamed human skin of the huPBL-SCID-huSkin model we here identified: 1. Parameters of dermal pathology that enable precise quantification of the local skin inflammatory response exemplified by acanthosis, increased expression of human beta-defensin-2, Elafin, K16, Ki67 and reduced expression of K10 by microscopy and immunohistochemistry. 2. Induction of human cytokines and chemokines using quantitative real-time PCR. 3. Influx of inflammation associated IL-17A-producing human CD4+ and CD8+ T cells as well as immunoregulatory CD4+Foxp3+ cells using immunohistochemistry and -fluorescence, suggesting that active immune regulation is taking place locally in the inflamed skin. 4. Systemic responses that revealed activated and proliferating human CD4+ and CD8+ T cells that acquired homing marker expression of CD62L and CLA. Finally, we demonstrated the value of the newly identified parameters by showing significant changes upon systemic treatment with the T cell inhibitory agents cyclosporine-A and rapamycin. In summary, here we equipped the huPBL-SCID-huSkin humanized mouse model with relevant tools not only to quantify the inflammatory dermal response, but also to monitor the peripheral immune status. This combined approach will gain our understanding of the dermal immunopathology in humans and benefit the development of novel therapeutics for controlling inflammatory skin diseases

Supersaturation of Calcipotriene and Betamethasone Dipropionate in a Novel Aerosol Foam Formulation for Topical Treatment of Psoriasis Provides Enhanced Bioavailability of the Active Ingredients

<p><b>Article full text</b></p> <p><br></p> <p>The full text of this article can be found here<b>. </b><a href="https://link.springer.com/article/10.1007/s13555-016-0125-6">https://link.springer.com/article/10.1007/s13555-016-0125-6</a></p><p></p> <p><br></p> <p><b>Provide enhanced content for this article</b></p> <p><br></p> <p>If you are an author of this publication and would like to provide additional enhanced content for your article then please contact <a href="http://www.medengine.com/Redeem/”mailto:[email protected]”"><b>[email protected]</b></a>.</p> <p><br></p> <p>The journal offers a range of additional features designed to increase visibility and readership. All features will be thoroughly peer reviewed to ensure the content is of the highest scientific standard and all features are marked as ‘peer reviewed’ to ensure readers are aware that the content has been reviewed to the same level as the articles they are being presented alongside. Moreover, all sponsorship and disclosure information is included to provide complete transparency and adherence to good publication practices. This ensures that however the content is reached the reader has a full understanding of its origin. No fees are charged for hosting additional open access content.</p> <p><br></p> <p>Other enhanced features include, but are not limited to:</p> <p><br></p> <p>• Slide decks</p> <p>• Videos and animations</p> <p>• Audio abstracts</p> <p>• Audio slides</p

Infiltration of human IL-17A-producing T cells and CD4+ Foxp3-expressing T cells in the inflamed human skin in the SCID/skin allograft mouse model.

<p><b>A.</b> Immunohistochemistry of human CD4 (brown, top) and CD8 (brown, bottom) expression in human skin grafts from SCID beige mice 21 days after infusion or huPBMC. Photographs show representative examples. 20× magnification. <b>B.</b> Summarized data of figure A. showing mean±SEM CD4 (top) or CD8 (bottom) positive cells/mm² of n = 4 and 10 upon PBS and huPBMC infusion resp in the epidermis (white bars) and dermis (black bars). <b>C.</b> Immunohistochemistry of human IL-17A expression in human skin grafts from SCID beige mice 21 days after infusion of PBS (left) or huPBMC (right). Photographs show representative examples of n = 6 (huPBMCs) n = 3 (controls). 20× magnification. Graph shows summarized data of IL-17A positive cells/mm² following PBS or huPBMC infusion in the human skin biopsies (mean±SEM, of n = 4 and 10). <b>D.</b> Immunohistochemistry of coexpression of human CD4 (blue) and IL-17A (red, top) and CD8 (blue) and IL-17A (red, bottom) in human skin grafts from SCID beige mice 21 days after infusion of huPBMC (20× magnification). Inserts show a higher magnification (40×) of single CD4/CD8 and IL-17A staining and CD4/IL-17A or CD8/IL-17A co-staining. . Photographs show representative examples of n = 6. <b>E.</b> Immunohistochemistry of IL-17A (red) in human mastcell tryptase (brown) and granulocyte elastase (brown) in human skin biopsies from SCID beige mice 21 days after infusion of PBS (left) or huPBMC (right). Photographs show representative examples of n = 6 (huPBMCs) n = 3 (controls). 20× magnification. <b>F.</b> Immunohistochemistry of co-expression of human Foxp3 (brown) and CD4 (blue) in human skin grafts from SCID beige mice 21 days after infusion of PBS (left) or huPBMC (right) (40× magnification). Inserts show a higher magnification (63×) of single Foxp3 and CD4+ staining and Foxp3/CD4 co-staining. Photographs show representative examples of n = 6 (huPBMCs) n = 3 (controls).</p