Psoriasiform Skin Inflammation In Mice Research Articles

Effects of topical isoxsuprine ointment on imiquimod-induced psoriasiform skin inflammation in mice.

This study assesses the potential positive impact of a 0.05% isoxsuprine ointment on psoriasiform skin inflammation generated by imiquimod in mouse models. Thirty-two male albino mice were allocated into four groups: the control group (which received topical emollients twice daily for 16days), the induction group (which received imiquimod cream (5%) for 8days, twice daily followed by petrolatum gel (15%) for another 8days), and the other two groups, which received imiquimod cream (5%) for 8days followed by either clobetasol ointment (0.05%) or isoxsuprine ointment (0.05%) twice daily for an additional 8days. At the end of the experiment, mice were sacrificed by ethical standards, and levels of TNF-α, IL-6, IL-17A, IL-23, and VEGF were measured; PASI and Backer's score were examined, in addition to the histopathology of skin tissue. Each clobetasol and isoxsuprine group displayed a significant reduction in tissue homogenate levels of TNF-α, IL-6, IL-17A, IL-23, and VEGF, besides increments in IL-10 compared to the induction group. Some markers (IL-17A, IL23, and VEGF) showed no significant difference between clobetasol and the isoxsuprine group. In contrast, the other markers (TNF-α, IL6, and IL10) showed significant differences between clobetasol and isoxsuprine groups. Isoxsuprine ointment showed comparable efficacy to clobetasol ointment in treating imiquimod-induced psoriasiform skin inflammation in mice models, probably due to its possible effect of anti-inflammatory and immunomodulatory activities.

Intestinal dysbiosis exacerbates the pathogenesis of psoriasis-like phenotype through changes in fatty acid metabolism

The intestinal microbiota has been associated with host immunity as well as psoriasis; however, the mechanism of intestinal microbiota regulating psoriasis needs to be demonstrated systematically. Here, we sought to examine its role and mechanism of action in the pathogenesis of psoriasis. We found that the severity of psoriasis-like skin phenotype was accompanied by changes in the composition of the intestinal microbiota. We performed co-housing and fecal microbial transplantation (FMT) experiments using the K14-VEGF transgenic mouse model of psoriasis and demonstrated that the transfer of intestinal microbiota from mice with severe psoriasis-like skin phenotype exacerbated psoriasiform skin inflammation in mice with mild symptoms, including increasing the infiltration and differentiation of Th17, and increased the abundance of Prevotella, while decreasing that of Parabacteroides distasonis, in the colon. These alterations affected fatty acid metabolism, increasing the abundance of oleic and stearic acids. Meanwhile, gentamicin treatment significantly reduced the abundance of Prevotella and alleviated the psoriasis-like symptoms in both K14-VEGF mice and imiquimod (IMQ)-induced psoriasis-like mice. Indeed, administration of oleic and stearic acids exacerbated psoriasis-like symptoms and increased Th17 and monocyte-derived dendritic cell infiltration in the skin lesion areas in vivo, as well as increased the secretion of IL-23 by stimulating DCs in vitro. At last, we found that, treatment of PDE-4 inhibitor alleviated psoriasis-like phenotype of K14-VEGF mice accompanied by the recovery of intestinal microbiota, including the decrease of Prevotella and increase of Parabacteroides distasonis. Overall, our findings reveal that the intestinal microbiota modulates host metabolism and psoriasis-like skin inflammation in mice, suggesting a new target for the clinical diagnosis and treatment of psoriasis.

Narciclasine inhibits phospholipase A2 and regulates phospholipid metabolism to ameliorate psoriasis-like dermatitis.

Psoriasis is a common inflammatory skin disease recognized by the World Health Organization as "an incurable chronic, noninfectious, painful, disfiguring and disabling disease." The fact that metabolic syndrome (MetS) is the most common and important comorbidities of psoriasis suggests an important role of lipid metabolism in the pathogenesis of psoriasis. Narciclasine (Ncs) is an alkaloid isolated from the Amaryllidaceae plants. Its biological activities include antitumor, antibacterial, antiinflammatory, anti-angiogenic and promoting energy expenditure to improve dietinduced obesity. Here, we report that Ncs may be a potential candidate for psoriasis, acting at both the organismal and cellular levels. The therapeutic effect of Ncs was assessed in IMQ-induced psoriasis-like mouse model. Then, through in vitro experiments, we explored the inhibitory effect of Ncs on HaCaT cell proliferation and Th17 cell polarization; Transcriptomics and lipidomics were used to analyze the major targets of Ncs; Single-cell sequencing data was used to identify the target cells of Ncs action. Ncs can inhibit keratinocyte proliferation and reduce the recruitment of immune cells in the skin by inhibiting psoriasis-associated inflammatory mediators. In addition, it showed a direct repression effect on Th17 cell polarization. Transcriptomic and lipidomic data further revealed that Ncs extensively regulated lipid metabolismrelated genes, especially the Phospholipase A2 (PLA2) family, and increased antiinflammatory lipid molecules. Combined with single-cell data analysis, we confirmed that keratinocytes are the main cells in which Ncs functions. Taken together, our findings indicate that Ncs alleviates psoriasiform skin inflammation in mice, which is associated with inhibition of PLA2 in keratinocytes and improved phospholipid metabolism. Ncs has the potential for further development as a novel anti-psoriasis drug.

Effect of Topical Tadalafil Gel in Imiquimod-induced Psoriasiform Skin Inflammation in Mice

Effect of Topical Tadalafil Gel in Imiquimod-induced Psoriasiform Skin Inflammation in Mice

Effects of tumor necrosis factor-like ligand 1A (TL1A) on imiquimod-induced psoriasiform skin inflammation in mice.

TL1A, as a master regulatory cytokine, plays a key role in the development of diverse T-cell-mediated inflammatory and autoimmune diseases. Our study is to further understand the roles of TL1A in the pathogenic mechanism of psoriasis and to find a possible new therapeutic strategy in the treatment of psoriasis. The direct effects of TL1A injection in mice skin and the therapeutic effects of TL1A blockade in imiquimod (IMQ)-induced psoriasis-like mouse model were researched in this study. First, we found that the expressions of TL1A in IMQ-treated lesions were significantly higher than Vaseline control group. And then, the results showed that TL1A injection exacerbated the psoriasiform phenotype on IMQ-treated skin (including clinical score, epidermal thickness changes, and Baker score) by increasing the number of T cells, neutrophils, and DCs, and upregulating the mRNA expression of IFN-γ and IL-17. However, anti-TL1A mAb can alleviate psoriasis-like lesions in clinical and effectively improved the histopathologic changes in IMQ-induced psoriasis-like mice after treatment. Moreover, anti-TL1A mAb also reduced the number of infiltrated CD3+ T cells, MPO+ neutrophils, and CD11c+ DCs in psoriasis-like lesions, and obviously decreased the expression of IFN-γ and IL-17 in psoriasis-like lesions. Data suggested that TL1A might be involved in the pathogenesis of psoriasis, and targeting TL1A by anti-TL1A mAb might provide a solid foundation and novel therapeutic sight in the treatment of psoriasis.

P38α signaling in Langerhans cells promotes the development of IL-17-producing T cells and psoriasiform skin inflammation.

Dendritic cells (DCs) contribute to psoriasis pathogenesis. In a mouse model of imiquimod-induced psoriasiform skin inflammation, we found that p38α activity in Langerhans cells (LCs), a skin-resident subset of DCs, promoted the generation of T cells that produce IL-17, a proinflammatory cytokine that is implicated in autoimmune disease. Deletion of p38α in LCs, but not in other skin or circulating DC subsets or T cells, decreased T cell-mediated psoriasiform skin inflammation in mice. The activity of p38α in LCs specifically promoted IL-17 production from γδ and CD4+ T cells by increasing the abundance of IL-23 and IL-6, two cytokines that stimulate IL-17 secretion. Inhibition of p38 activity through either pharmacological inhibition or genetic deletion also reduced the severity of established psoriasiform skin inflammation. Together, our findings indicate a critical role for p38α signaling in LCs in promoting inflammatory responses in the skin and suggest that targeting p38α signaling in LCs may offer an effective therapeutic approach to treat psoriasis.

Effects of interleukin-36α on psoriasiform skin lesions and C-C motif chemokine ligand 20 expression in mice

Objective To evaluate effects of interleukin-36α (IL-36α) on psoriasiform skin lesions and C-C motif chemokine ligand 20 (CCL20) expression in mice. Methods Totally, 30 BALB/c female mice were randomly and equally divided into 3 groups: control group treated with topical vaseline cream on the shaved back and intracutaneous injection with phosphate buffer saline (PBS) , model group treated with topical imiquimod cream on the shaved back and intracutaneous injection with PBS, experimental group treated with topical imiquimod cream on the shaved back and intracutaneous injection with IL-36α solution. Psoriasis area severity index (PASI) was used to evaluate changes of psoriasiform skin lesions in mice, and light microscopy to observe morphological changes of skin lesions and to measure the thickness of the epidermis. Real-time fluorescence-based quantitative PCR (qRT-PCR) and Western blot analysis were performed to determine the expression of IL-36α in skin lesions in the control group and model group, and qRT-PCR, Western blot analysis and immunohistochemical study to evaluate changes of CCL20 levels in skin lesions. Results The model group showed significantly increased mRNA (∆Ct value: 0.0195 ± 0.0059) and protein expression (3.922 ± 0.248) of IL-36α compared with the control group (mRNA: 0.0012 ± 0.0004, P < 0.05; protein: 0.690 ± 0.025, P < 0.05) . The mRNA and protein expression of CCL20 were significantly higher in the experimental group than those in the model group (mRNA: 2.152 ± 0.793 vs. 0.999 ± 0.178; protein: 0.397 ± 0.033 vs. 0.145 ± 0.030; both P < 0.05) , and higher in the model group than those in the control group (mRNA: 0.378 ± 0.075; protein: 0.025 ± 0.009; both P < 0.05) . Immunohistochemical study showed that the expression intensity of CCL20 in skin lesions significantly increased in the experimental group compared with that in the model group (Z= 2.294, P < 0.05) . Conclusion IL-36α may aggravate psoriasiform skin inflammation in mice by promoting CCL20 expression. Key words: Psoriasis; Disease models, animal; Chemokine CCL20; Imiguimod; Interleukin-36α

KLK6 is required for imiquimod-induced psoriasiform skin inflammation in mice

KLK6 is required for imiquimod-induced psoriasiform skin inflammation in mice

Dual Inhibition of TNFR1 and IFNAR1 in Imiquimod-Induced Psoriasiform Skin Inflammation in Mice.

Psoriasis is a chronic inflammatory skin disease affecting 2-3% of the world population and is mainly characterized by epidermal hyperplasia, scaling, and erythema. A prominent role for TNF in the pathogenesis of psoriasis has been shown, and consequently various types of TNF antagonists such as etanercept and infliximab have been used successfully. Recently, increasing amounts of data suggest that type I IFNs are also crucial mediators of psoriasis. To investigate whether blocking their respective receptors would be useful, TNFR1- and IFNAR1-deficient mice were challenged with Aldara, which contains imiquimod, and is used as an experimental model to induce psoriasis-like skin lesions in mice. Both transgenic mice showed partial protection toward Aldara-induced inflammation compared with control groups. Additionally, TNFR1 knockout mice showed sustained type I IFN production in response to Aldara. Double knockout mice lacking both receptors showed superior protection to Aldara in comparison with the single knockout mice and displayed reduced levels of IL-12p40, IL-17F, and S100A8, indicating that the TNF and type I IFN pathways contribute significantly to inflammation upon treatment with Aldara. Our findings reveal that dual inhibition of TNFR1 and IFNAR1 may represent a potential novel strategic treatment of psoriasis.

Skin-penetrating methotrexate alleviates imiquimod-induced psoriasiform dermatitis via decreasing IL-17-producing gamma delta T cells.

Accumulating evidence has shown that the Toll-like receptor 7 agonist imiquimod (IMQ) induces psoriasiform skin inflammation in mice and that this inflammation is dependent on the IL-23/IL-17 axis. Moreover, it has been demonstrated that the main source of IL-17 is not Th17 but is dermal gamma delta (γδ) T cells in mouse psoriasiform skin. Recent advances in the understanding of immunopathogenesis of psoriasis led to an alteration in the treatment paradigm to the use of highly efficacious biologics. However, their high cost impedes the extensive use of these agents. Thus, inexpensive and safe medications are still considered valuable. In this study, we introduce the therapeutic efficacy of a newly formulated methotrexate (MTX), a chemical conjugate of MTX with cell permeable peptide, for the treatment of psoriasis. Topically applied skin-penetrating (SP)-MTX reduced the psoriasiform skin phenomenon, epidermal thickness and infiltrating immune cells into the dermis. IL-17A-producing dermal γδ T cells in the cellular infiltrate that contribute IL-23/IL-17 axis were well abrogated by SP-MTX. Furthermore, SP-MTX had no toxic effects on liver, kidney or myeloid cells, unlike systemic administration of MTX. In conclusion, topically applied SP-MTX ameliorated psoriasiform skin inflammation in mice with the criteria of clinical phenomenon, histopathology and immunology, without inducing systemic toxic effects.

Prolactin induces the production of Th17 and Th1 cytokines/chemokines in murine Imiquimod‐induced psoriasiform skin

Prolactin (PRL) is a pituitary-derived neuropeptide hormone that has been suggested to promote the development of psoriasis, a Th17/Th1-mediated inflammatory dermatosis. PRL increases the expression of Th1 cytokines; however, its effects on Th17 responses are unknown. This study aims to determine the in vivo effects of PRL on the expression of Th17 cytokines/chemokines in imiquimod-induced psoriasiform skin inflammation in mice. BALB/c mice were intraperitoneally injected with PRL or phosphate-buffered saline, and imiquimod cream or Vaseline was applied to the shaved back skin for six consecutive days. Intraperitoneal PRL increased the mRNA levels of IL-17A, IL-17F, IL-22, IL-23p19, IL-12p40, CCL20 and STAT3 in imiquimod-treated skin. Mice treated with imiquimod plus PRL, but not those treated with imiquimod plus phosphate-buffered saline, showed significantly increased mRNA levels of TNF-α, IFN-γ, IL-12p35 and CXCL2 compared with controls. Intraperitoneal PRL increased the numbers of CD3(+) and GR-1(+) cells in the dermis of imiquimod-treated skin. These results suggest that intraperitoneal PRL enhances the expression of Th17 and Th1 cytokines/chemokines, and augments inflammation in imiquimod-induced psoriasiform skin. Prolactin may thus exacerbate psoriasis through the enhancement of Th17/Th1 responses.

Heparanase is preferentially expressed in human psoriatic lesions and induces development of psoriasiform skin inflammation in mice

Heparanase is the sole mammalian endoglycosidase that selectively degrades heparan sulfate, the key polysaccharide associated with the cell surface and extracellular matrix of a wide range of tissues. Extensively studied for its capacity to promote cancer progression, heparanase enzyme was recently implicated as an important determinant in several inflammatory disorders as well. Applying immunohistochemical staining, we detected preferential expression of heparanase by epidermal keratinocytes in human psoriatic lesions. To investigate the role of the enzyme in the pathogenesis of psoriasis, we utilized heparanase transgenic mice in a model of 12-O-tetradecanoyl phorbol 12-myristate 13-acetate-induced cutaneous inflammation. We report that over-expression of the enzyme promotes development of mouse skin lesions that strongly recapitulate the human disease in terms of histomorphological appearance and molecular/cellular characteristics. Importantly, heparanase of epidermal origin appears to facilitate abnormal activation of skin-infiltrating macrophages, thus generating psoriasis-like inflammation conditions, characterized by induction of STAT3, enhanced NF-κB signaling, elevated expression of TNF-α and increased vascularization. Taken together, our results reveal, for the first time, involvement of heparanase in the pathogenesis of psoriasis and highlight a role for the enzyme in facilitating abnormal interactions between immune and epithelial cell subsets of the affected skin. Heparanase inhibitors (currently under clinical testing in malignant diseases) could hence turn highly beneficial in psoriatic patients as well.

IL-22 Is Required for Imiquimod-Induced Psoriasiform Skin Inflammation in Mice

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 imiquimod 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 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 hyperproliferative 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 γδ 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 Rag2(-/-) mice. Taken together, our data show that IL-22 is required for psoriasis-like lesions in the mouse imiquimod model and is produced by both T cells and innate immune cells.

PS2-047. IL-22 is required for imiquimod-induced psoriasiform skin inflammation in mice

PS2-047. IL-22 is required for imiquimod-induced psoriasiform skin inflammation in mice

Plasmin plays an essential role in amplification of psoriasiform skin inflammation in mice (164.10)

Abstract Background Although increased levels of plasminogen activators have been found in psoriatic lesions, the role of plasmin converted from plasminogen by plasminogen activators in pathogenesis of psoriasis has not been investigated. Methodology/Principal Findings Here we examined the contribution of plasmin to amplification of inflammation in psoriasis. We found that plasminogen was diminished, but that the amount and activity of its converted product plasmin were markedly increased in psoriasis. Moreover, annexin II, a receptor for plasmin was dramatically increased in both dermis and epidermis in psoriasis. Plasmin at sites of inflammation was pro-inflammatory, eliciting production of inflammatory factors, including CC chemokine ligand 20 (CCL20) and interleukin-23 (IL-23), that was mediated by the nuclear factor-κB (NF-κB) signaling pathway and that had an essential role in the recruitment and activation of pathogenic C-C chemokine receptor type 6 (CCR6)+ T cells. Moreover, intradermal injection of plasmin or plasmin together with recombinant MCP-1 resulted in induction of psoriasiform skin inflammation around the injection sites with several aspectsκof human psoriasis in mice. Conclusions/Significance Plasmin converted from plasminogen by plasminogen activators plays an essential role in amplification of psoriasiform skin inflammation in mice, and targeting plasmin receptor - annexin II - may harbor therapeutic potential for the treatment of human psoriasis.

Plasmin Plays an Essential Role in Amplification of Psoriasiform Skin Inflammation in Mice

BackgroundAlthough increased levels of plasminogen activators have been found in psoriatic lesions, the role of plasmin converted from plasminogen by plasminogen activators in pathogenesis of psoriasis has not been investigated.Methodology/Principal FindingsHere we examined the contribution of plasmin to amplification of inflammation in patients with psoriasis. We found that plasminogen was diminished, but that the amount and activity of its converted product plasmin were markedly increased in psoriasis. Moreover, annexin II, a receptor for plasmin was dramatically increased in both dermis and epidermis in psoriasis. Plasmin at sites of inflammation was pro-inflammatory, eliciting production of inflammatory factors, including CC chemokine ligand 20 (CCL20) and interleukin-23 (IL-23), that was mediated by the nuclear factor-kappaB (NF-κB) signaling pathway and that had an essential role in the recruitment and activation of pathogenic C-C chemokine receptor type 6 (CCR6)+ T cells. Moreover, intradermal injection of plasmin or plasmin together with recombinant monocyte/macrophage chemotactic protein-1 (MCP-1) resulted in induction of psoriasiform skin inflammation around the injection sites with several aspects of human psoriasis in mice.Conclusions/SignificancePlasmin converted from plasminogen by plasminogen activators plays an essential role in amplification of psoriasiform skin inflammation in mice, and targeting plasmin receptor - annexin II - may harbor therapeutic potential for the treatment of human psoriasis.