Double-negative T cells ameliorate psoriasis by selectively inhibiting IL-17A-producing γδlow T cells.

BACKGROUND: Psoriasis is a chronic immune-mediated skin condition. Although biologic treatments are effective in controlling psoriasis, some patients do not respond or lose response to these therapies. Thus, new strategies for psoriasis treatment are still urgently needed. Double-negative T cells (DNT) play a significant immunoregulatory role in autoimmune diseases. In this study, we aimed to evaluate the protective effect of DNT in psoriasis and explore the underlying mechanism. METHODS: We conducted a single adoptive transfer of DNT into an imiquimod (IMQ)-induced psoriasis mouse model through tail vein injection. The skin inflammation and IL-17A producing γδ T cells were evaluated. RESULTS: DNT administration significantly reduced the inflammatory response in mouse skin, characterized by decreased skin folds, scales, and red patches. After DNT treatment, the secretion of IL-17A by RORc+ γδlow T cells in the skin was selectively suppressed, resulting in an amelioration of skin inflammation. Transcriptomic data suggested heightened expression of NKG2D ligands in γδlow T cells within the mouse model of psoriasis induced by IMQ. When blocking the NKG2D ligand and NKG2D (expressed by DNT) interaction, the cytotoxic efficacy of DNT against RORc+IL17A+ γδlow T cells was attenuated. Using Ccr5-/- DNT for treatment yielded evidence that DNT migrates into inflamed skin tissue and fails to protect IMQ-induced skin lesions. CONCLUSIONS: DNT could migrate to inflamed skin tissue through CCR5, selectively inhibit IL-17-producing γδlow T cells and finally ameliorate mouse psoriasis. Our study provides feasibility for using immune cell therapy for the prevention and treatment of psoriasis in the clinic.

Protective effect and regulatory mechanism of salidroside on skin inflammation induced by imiquimod in psoriasis mice.

Salidroside (SAL) is a glucoside of tyrosol commonly existing in the roots of Rhodiola rosea. This study unveils the protective effect of SAL on skin inflammation in imiquimod (IMQ)-induced psoriasis. The mouse model of psoriasis was established by local application of IMQ, and SAL efficacy was evaluated through PASI scoring, H&E staining, and skin tissue pathology observation. The HaCaT cell model was established by interferon (IFN)-γ induction, followed by MTT assay detection of cell viability, detection of ROS, SOD, MDA, and CAT levels in skin tissues and cells using reagent kits, ELISA detection of inflammatory factors (TNF-α, IL-6, IL-1ß), and qRT-PCR detection of psoriasis-related genes (S100a9, Cxcl1, Cxcl2) as well as miR-369-3p and SMAD2 expressions. The binding relationship between miR-369-3p and SMAD2 was validated using dual-luciferase reporter assay. SAL treatment reduced PASI scores and alleviated psoriasis symptoms of IMQ-induced mice, and also augmented the viability and subsided the oxidative stress and inflammation of IFN-γ-treated HaCaT cells. SAL treatment restrained miR-369-3p expression but elevated SMAD2 expression. Mechanistically, miR-369-3p targeted SMAD2 expression. miR-369-3p overexpression or SMAD2 inhibition partially offset the alleviating effect of SAL on psoriasis skin inflammation. In conclusion, SAL alleviates skin inflammation in IMQ-induced psoriasis mice via the miR-369-3p/SMAD2 axis.

Bombesin receptor-activated protein homolog deficiency altered the pattern of pathological changes of psoriasis - like skin lesion in mice.

This study investigated the potential role of the mouse homolog of bombesin receptor-activated protein (BRAP) in imiquimod (IMQ) induced psoriasis - like skin inflammation. The expression of both human BRAP, encoded by C6orf89, and its mouse homolog, encoded by BC004004, has been found to be expressed abundantly in the keratinocytes. BC004004 knockout mice (BC004004-/-) were topically treated with IMQ daily for 7 days to test whether they were more vulnerable to psoriasis - like inflammation. We found that those mice exhibited an altered pattern of inflammation process compared to isogenic wild type control mice (BC004004+/+). BC004004-/- mice developed skin lesions with earlier and more acute onset, as well as a quicker remission. The cytokines related to pathogenesis of psoriasis also exhibited different expression patterns in IMQ treated BC004004-/- mice. On day 4 of IMQ treatment, BC004004-/- mice exhibited a higher expression level of IL-17A compared to BC004004+/+ mice, suggesting a more robust activation of Th17 cells in the knockout mice. The serum level of thymic stromal lymphopoietin (TSLP), one of the keratinocyte derived cytokines, was also increased in BC004004-/- mice and reached its peak on day 4. Knockdown of BRAP in cultured human keratinocyte-derived HaCaT cells by siRNA silencing led to increased release of TSLP. Our data suggest that the elevated of level of TSLP released from keratinocytes due to BRAP deficiency might mediate the crosstalk between the epidermal cells and immune cells and thereby contributing to the altered pathological changes observed in psoriasis - like skin lesion in knockout mice.

Livin expression promotes keratinocyte release of inflammatory mediators in psoriasis.

BACKGROUND: Psoriasis is a prevalent, long-term skin condition characterized by inflammation. Keratinocytes (KCs) are important effector cells that release inflammatory factors and chemokines to promote the inflammatory cascade in psoriasis. However, the mechanisms underlying the activation of KCs in psoriasis remain unclear. Livin suppresses apoptotic proteins and directly affects the growth and spread of cancer cells. Livin expression reportedly increases significantly in lesions of patients with psoriasis; however, its specific role in KC activation remains unknown. This study aimed to examine the impact of Livin on KC activation and the subsequent release of inflammatory mediators. METHODS: Immunofluorescence staining, reverse transcription-quantitative polymerase chain reaction, enzyme-linked immunosorbent assay (ELISA), and western blotting were used to assess Livin expression in patients with psoriasis, an imiquimod (IMQ)-induced psoriasis-like mouse model, and M5-treated HaCaT cells. To investigate the role of Livin in KCs, we performed RNA sequencing and proteomic analysis of Livin-knockdown (knockdown-HaCaT) and negative control (NC-HaCaT) cells. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes were used for enrichment analyses. Moreover, the effect of Livin expression on the release of inflammatory mediators in KCs was verified using ELISA. RESULTS: Livin expression was higher in KCs of patients with psoriasis than in those healthy controls. Livin expression in HaCaT cells treated with M5 increased significantly over time. Livin expression was higher in the skin lesions of the IMQ mouse model than in the control group. Proteomic analysis and RNA sequencing used to investigate the function of Livin in HaCaT cells revealed its potential role in mediating KC activation and inflammatory mediator release, which affected the pathology of psoriasis. CONCLUSIONS: Livin expression played an effect on KCs activation, which induced release of inflammatory mediators and up-regulation of keratin. This study provides a new effector molecule for the mechanism of inflammatory response in psoriasis.

The Impact of Proinflammatory Cytokines and Imiquimod on GLUT1 in HaCaT Keratinocytes - a Potential Anti-Psoriatic Therapeutic Target?

BACKGROUND/AIMS: Glucose metabolism has been proven as an essential process for proliferating keratinocytes, which highlights the importance of glucose transporter-1 (GLUT1) not only in the onset of psoriasis but also in the progression and severity of this inflammation-driven disease. In this study, we attempted to find a connection between proinflammatory cytokines (IL-6, IL-17, IL-23, IL-36, TNF-α), a skin inflammation inducing agent - imiquimod (IMQ) and GLUT1 expression. METHODS: Human keratinocyte HaCaT cell line was incubated with exogenous cytokines: IL-6, IL-17A, IL-23, IL-36, TNF-α at a final concentration of 100 ng/ml, or with 1 µM of IMQ, for 48 h. Following the stimulation, glucose uptake and GLUT1 expression were evaluated. The activity of GLUT1 was measured in the presence of a selective GLUT1 inhibitor, BAY-876. The expression of GLUT1 was examined by immunofluorescence and quantified by qPCR, Western blotting and densitometry. RESULTS: The results from qPCR analysis showed that the administration of exogenous IL-6, IL-17, IL-23 and IL-36 to HaCaT cells resulted in upregulation of GLUT1-encoding SLC2A1 gene, while TNF-α had no significant effect. The same results were confirmed by immunofluorescence analysis, as the fluorescent intensity of GLUT1 was elevated following cytokine and IMQ stimulation. Western blot and densitometry showed that all examined cytokines, as well as IMQ, increased GLUT1 expression. HaCaT cells displayed an improved intracellular 2-deoxy-D-glucose (2-DG) uptake and GLUT1 activity after stimulation by exogenous cytokines and IMQ. The highest uptake of 2-DG was observed after IL-23 stimulation (1.93x) and the lowest after TNF-α stimulation (1.07x). BAY-876 inhibited the 2-DG uptake compared to control. CONCLUSION: Our findings suggest that cytokines and IMQ may play a key role in regulating GLUT1 expression in HaCaT cells. We believe that GLUT1 overexpression could potentially be utilized in the targeted treatment of psoriasis.

Comparative studies on mannan and imiquimod induced experimental plaque psoriasis inflammation in inbred mice.

Psoriasis is a genetically determined, environmentally triggered, immune system-mediated autoimmune disease. Different animal models are needed to investigate the complex pathological mechanisms underlying this disease. Therefore, we established mannan-induced psoriasis model and compared with the most commonly used imiquimod-induced psoriasis in terms of disease, induction of innate immune cells, expression of cytokines, and the effect of dexamethasone treatment. Mannan significantly induced more severe psoriasis with better disease relapsing feature than imiquimod (IMQ). As determined by immunohistochemistry, IMQ induced significantly more infiltration of CD11c+ and F4/80+ cells than mannan in the skin. However, cytometric analysis showed a significant increase in the percentage of Gr-1+ neutrophils in the spleen and lymph nodes as well as F4/80+ macrophages in the spleen after mannan exposure. Variation in the percentage of significantly increased Vγ4 T cells was also found to be dependent on the lymphoid organs tested. However, there is a clear difference between these models in terms of expression of certain cytokine genes: IL-22, IL-23, IL-17E, and IL-17F were expressed more predominantly in mannan-induced inflammation, while IL-6 and IL-17A expressions were significantly higher in IMQ model. Interestingly, dexamethasone treatment strongly reduced epidermal thickness and histological scores induced by mannan than IMQ. Despite inducing psoriasis-like inflammation, certain differences and similarities were observed in the immune responses induced by mannan and IMQ. However, mannan-induced psoriasis model is relatively more simple, economical and less harmful to mice with an increased possibility to develop a chronic psoriasis model by exposing mice to mannan.

Nanaomycin E inhibits NLRP3 inflammasome activation by preventing mitochondrial dysfunction.

Nod-like receptor family pyrin domain-containing 3 (NLRP3) is a cytosolic innate immune receptor that senses organelle dysfunction induced by various stimuli, such as infectious, environmental, metabolic and drug stresses. Upon activation, NLRP3 forms an inflammasome with its adaptor protein apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and caspase-1, to trigger the release of inflammatory cytokines. The development of effective anti-inflammatory drugs targeting the NLRP3 inflammasome is in high demand as its aberrant activation often causes inflammatory diseases. Here, we found that nanaomycin A (NNM-A), a quinone-based antibiotic isolated from Streptomyces, effectively inhibited NLRP3 inflammasome-mediated inflammatory responses induced by imidazoquinolines, including imiquimod. Interestingly, its epoxy derivative nanaomycin E (NNM-E) showed a comparable inhibitory effect against the NLRP3 inflammasome-induced release of interleukin (IL)-1ß and IL-18 from macrophages, with a much lower toxicity than NNM-A. NNM-E inhibited ASC oligomerization and caspase-1 cleavage, both of which are hallmarks of NLRP3 inflammasome activation. NNM-E reduced mitochondrial damage and the production of reactive oxygen species, thereby preventing the activation of the NLRP3 inflammasome. NNM-E treatment markedly alleviated psoriasis-like skin inflammation induced by imiquimod. Collectively, NNM-E inhibits NLRP3 inflammasome activation by preventing mitochondrial dysfunction with little toxicity and showed an anti-inflammatory effect in vivo. Thus, NNM-E could be a potential lead compound for developing effective and safe anti-inflammatory agents for the treatment of NLRP3 inflammasome-mediated inflammatory diseases.

Staphylococcus warneri strain XSB102 exacerbates psoriasis and promotes keratinocyte proliferation in imiquimod-induced psoriasis-like dermatitis mice.

Psoriasis is one of the common chronic inflammatory skin diseases worldwide. The skin microbiota plays a role in psoriasis through regulating skin homeostasis. However, the studies on the interactions between symbiotic microbial strains and psoriasis are limited. In this study, Staphylococcus strain XSB102 was isolated from the skin of human, which was identified as Staphylococcus warneri using VITEK2 Compact. To reveal the roles of Staphylococcus warneri on psoriasis, XSB102 were applied on the back of imiquimod-induced psoriasis-like dermatitis mice. The results indicated that it exacerbated the psoriasis and significantly increased the thickening of the epidermis. Furthermore, in vitro experiments confirmed that inactivated strain XSB102 could promote the proliferation of human epidermal keratinocytes (HaCaT) cell. However, real-time quantitative PCR and immunofluorescence results suggested that the expression of inflammatory factors such as IL-17a, IL-6, and so on were not significantly increased, while extracellular matrix related factors such as Col6a3 and TGIF2 were significantly increased after XSB102 administration. This study indicates that Staphylococcus warneri XSB102 can exacerbate psoriasis and promote keratinocyte proliferation independently of inflammatory factors, which paves the way for further exploration of the relationship between skin microbiota and psoriasis.

Discovery of 5-((1H-indazol-3-yl) methylene)-2-thioxoimidazolidin-4-one derivatives as a new class of AHR agonists with anti-psoriasis activity in a mouse model.

Aryl hydrocarbon receptor (AHR) is a ligand dependent transcription factor and participates in the regulation of the immune balance of Th17/22 and Treg cells. It has been found to be widely expressed in the skin, and involved in the pathology of psoriasis. Therefore, AHR is thought as a potential intervention target for psoriasis. Here, we report the discovery of 5-((1H-indazol-3-yl) methylene)-2-thioxoimidazolidin-4-one derivatives as a new class of AHR agonists. Structure-activity relationship analyses led to the identification of the most active compound, 5- ((1H-indazol-3-yl)methylene) -3- (prop-2-yn-1-yl) -2-thiooimidazolidin-4-one (24e), which exhibited an EC50 value of 0.015 µM against AHR. Mechanism of action studies showed that 24e regulated the expression of CYP1A1 by activating the AHR pathway. Topical administration of 24e substantially alleviated imiquimod (IMQ)-induced psoriasis-like skin lesion. Overall, compound 24e could be a good lead compound for drug discovery against psoriasis, and hence deserving further in-depth studies.

Characterization of spinal microglial activation in a mouse model of imiquimod-induced psoriasis.

Although microglia are associated with chronic pain, the role of spinal microglia in the regulation of itch remains unclear. In this study, we characterized spinal microglial activation in a mouse model of imiquimod (IMQ)-induced psoriasis. Hypertrophic (activated) microglia were observed throughout the spinal cord after the topical application of IMQ. Furthermore, the mRNA expression of microglial markers and inflammatory mediators was upregulated. Ablation of itch-related sensory neurons using resiniferatoxin decreased itch-related scratching behavior and the number of hypertrophic microglia in the spinal dorsal horn. Conclusively, sensory neuron input may partially contribute to spinal microglial activation after IMQ application.

TFAP2C exacerbates psoriasis-like inflammation by promoting Th17 and Th1 cells activation through regulating TEAD4 transcription.

BACKGROUND: Psoriasis is one of the chronic and autoimmune skin diseases. It is important to uncover the mechanisms underlying the psoriasis. Transcription factor activator protein (TFAP-2) gamma, also known as AP2-gamma, is a protein encoded by the TFAP2C gene. Immune-mediated pathophysiological processes could be linked to psoriasis, but the mechanism is still unclear. Therefore, to date the cause of psoriasis has not been understood completely. MATERIALS AND METHODS: Psoriasis is a complex disease triggered by genetic, immunological, and environmental stimuli. Keratinocytes play an important role in both initiation and maintenance phases of psoriasis. A psoriatic keratinocyte model was established by stimulating high sensitivity of human epidermal keratinocytes (HaCaT) to topoisomerase inhibitor cell lines using the accumulation of M5 cytokines comprising interleukin (IL)-17A, IL-22, oncostatin M, IL-1α, and tumor necrosis factor-α (TNF-α). The TFAP2C and transcriptional enhanced associate domain 4 (TEAD4) genes expression was evaluated by reverse transcription-quantitative polymerase chain reaction. Western blot analysis was used to examine protein expression. Cell viability (quantitative) of keratinocytes, including cytotoxicity, proliferation, and cell activation, was evaluated by the MTT assay. The relative percentage values of interleukin (IL)-17a, interferon gamma, and IL-4+ cells were measured by flow cytometry. Accordingly, chromatin immunoprecipitation and luciferase reporter assays were applied to evaluate the binding affinity of TFAP2C and TEAD4 promoter. RESULTS: Level of the TFAP2C gene was elevated in the lesional skin of psoriasis patients. On the other hand, silencing of the TFAP2C gene suppressed the proliferation and inflammatory response in M5-induced keratinocytes. In addition, inhibition of TFAP2C alleviated imiquimod (IMQ)-induced skin injury in mice model. We also observed that suppression of TFAP2C inhibited the activation of T-helper 17 (Th17) and Th1 cells in IMQ-induced mice model. Mechanically, TFAP2C promoted TEAD4 transcriptional activation. CONCLUSION: TFAP2C exacerbated psoriasis-like inflammation by increasing the activation of Th17 and Th1 cells by regulating TEAD4 transcription. This finding clearly indicated that TFAP2C could be considered a valuable biomarker for the prevention and treatment for psoriasis.

Isostearic acid is an active component of imiquimod formulations used to induce psoriaform disease models.

Topical imiquimod based creams are indicated as immune stimulants for papillomas and various skin neoplasms. Imiquimod is considered a TLR7 ligand. These creams are also used in research to induce skin inflammation in mice as a model for psoriasis. We observed that this inflammatory response was not strictly imiquimod dependent and we set out to establish which components drive the proinflammatory effects. To this end, we examined the induction response in a BALB/cJRj mouse model, in which 50 mg of cream is applied to 2 cm2 of skin (125 mg/kg imiquimod-5% W/V, and/or 625 mg/kg isostearic acid-25% W/V). Comparing cream formulations containing isostearic acid, imiquimod and the combination, we observed that isostearic acid causes skin inflammation within 2 days, whereas imiquimod requires up to 5 days for initial signs. Isostearic acid activated an inflammasome response, stimulated release of proinflammatory cytokines and upregulated the IL-23/17 axis. Animals treated with isostearic acid had enlarged livers (+ 40% weight), which was not observed with imiquimod alone. Imiquimod was readily metabolized and cleared from plasma and liver, but was maintained at high levels in the skin throughout the body (200 mM at area of application; 200 µM in untreated skin). Imiquimod application was associated with splenomegaly, cytokine induction/release and initial body weight loss over 3 days. Despite high imiquimod skin levels throughout the animal, inflammation was only apparent in the treated areas and was less severe than in isostearic acid groups. As the concentrations in these areas are well above the 10 µM required for TLR7 responses in vitro, there is an implication that skin inflammation following imiquimod is due to effects other than TLR7 agonism (e.g., adenosine receptor agonism). In brain, isostearic caused no major changes in cytokine expression while imiquimod alone sightly stimulated expression of IL-1ß and CCL9. However, the combination of both caused brain induction of CCL3, -9, CXCL10, -13, IL-1ß and TNFα. The implication of these data is that isostearic acid facilitates the entry of imiquimod or peripherally secreted cytokines into the brain. Our data suggest that psoriaform skin responses in mice are more driven by isostearic acid, than generally reported and that the dose and route used in the model, leads to profound systemic effects, which may complicate the interpretation of drug effects in this model.

Human umbilical cord-derived mesenchymal stem cells ameliorate psoriasis-like dermatitis by suppressing IL-17-producing γδ T cells.

Mesenchymal stem cells (MSCs) have shown great potential in treating autoimmune diseases due to their immunomodulatory capability, which has been verified in both animal experiments and clinical trials. Psoriasis is a chronic and remitting immune-related disease. Limited studies have demonstrated that MSCs might be an effective therapeutic approach for managing psoriasis, whose underlying mechanism remains to be elucidated. In our present study, human umbilical cord-derived MSCs (hUC-MSCs) were subcutaneously injected into mice with imiquimod (IMQ)-induced psoriasis-like skin inflammation to explore the feasibility of this cellular therapy. The severity of psoriasis-like dermatitis was evaluated by cumulative psoriasis area and severity index score and epidermal thickness of skin tissue sections. Flow cytometric analysis was utilized to detect T helper cells, regulatory T cells, and γδ T cells in skin-draining lymph nodes. Real-time quantitative polymerase chain reaction and enzyme-linked immunosorbent assay were used to assess the expression levels of psoriasis-related cytokines and chemokines in mouse dorsal skin lesions. We discovered that hUC-MSCs drastically diminished the severity of IMQ-induced psoriasis-like dermatitis and suppressed inflammatory cell response. Although the tail vein injection of hUC-MSCs was also effective, it was correlated with higher mortality owing to pulmonary embolism. By comparison, subcutaneous injection with two million hUC-MSCs was identified to be the optimal therapeutic strategy. Furthermore, we uncovered that hUC-MSCs might repress skin inflammation probably through inhibiting interleukin-17-producing γδ T cells. In conclusion, subcutaneous administration of hUC-MSCs might be a promising therapeutic approach for psoriasis. Our findings provide novel insights into the underpinning mechanism of hUC-MSC treatment in the management of psoriasis.

Topical VX-509 attenuates psoriatic inflammation through the STAT3/FABP5 pathway in keratinocytes.

BACKGROUND: Psoriasis is a chronic inflammatory disease, with lesions mainly manifesting as scaly erythematous plaques. The mild or moderate of psoriasis is the main type of patients in hospital, and topical application remains the preferred treatment option for psoriasis therapy, therefore, the development of novel topical agents has an essential role in psoriasis therapy. OBJECTIVE: To identify potential drugs for psoriasis topical treatment. METHODS: We performed drug screening by Imiquimod (IMQ)-induced psoriatic like inflammation in mouse model, followed mouse epidermis by RNA-seq to find the key molecules affecting the drug. The qRT-PCR, WB were performed to test mRNA and protein expression, and Chip assay had been conducted to examine Stat3 bound to promoter of FABP5. RESULTS: In this study, we identified VX-509, which topical application significantly attenuated IMQ-induced psoriatic like inflammation in mouse model. And then, we verified Epidermal Fatty acid binding protein (E-FABP/FABP5) was significantly decreased in VX-509 treated mouse epidermis by RNA-seq. FABP5 is a key molecule in lipid metabolism, administration of FABP5 inhibitor or knock down of FABP5 expression remarkably abrogated psoriatic inflammation as well as lipid metabolism. Mechanistically, our finding showed that VX-509 blocked IL-22 induced signaling pathway, particular in activation of Stat3. Furthermore, we identified Stat3 is a transcriptional factor associated with FABP5 promoters and VX-509 treatment remarkably attenuated IL-22-induced FABP5 expression through Stat3 in KCs. CONCLUSIONS: This study demonstrated administration of VX-509 is a potential promising topical drug for treatment of psoriasis, FABP5 is a critical targeted molecule in psoriasis therapy.

Knockdown of Bcl-3 alleviates psoriasis and dyslipidemia comorbidity by regulating Akt pathway.

BACKGROUND: Psoriasis is considered as an inflammatory skin disease accompanied by dyslipidemia comorbidity. B-cell leukemia-3 (Bcl-3) belongs to IκB (inhibitor of nuclear factor kappa B [NF-κB]) family, and regulates inflammatory response through associating with NF-κB. The role of Bcl-3 in psoriasis was investigated in this study. METHODS: Apolipoprotein E (ApoE)-deficient mice were treated with imiquimod to induce psoriasis and dyslipidemia. Mice were injected intradermally in the back with lentiviral particles encoding Bcl-3 small hairpin RNA (shRNA). Hematoxylin and eosin were used to detect pathological characteristics. The blood lipid levels were determined by automatic biochemical analyzer, and inflammation was assessed by enzyme-linked-immunosorbent serologic assay and real-time quantitative reverse transcription polymerase chain reaction. RESULTS: Bcl-3 was elevated in imiquimod-induced ApoE-deficient mice. Injection with lentiviral particles encoding Bcl-3 shRNA reduced Psoriasis area and severity index (PASI) score in ApoE-deficient psoriatic mice. Knockdown of Bcl-3 also ameliorated imiquimod-induced psoriasiform skin lesions in ApoE-deficient mice. Moreover, loss of Bcl-3 enhanced expression of loricrin, an epidermal barrier protein, reduced expression of proliferating cell nuclear antigen (PCNA) and lectin-like oxidized LDL (oxLDL) receptor-1 (LOX-1) in imiquimod-induced ApoE-deficient mice. The enhanced levels of blood lipid in ApoE-deficient mice were attenuated by silencing of Bcl-3 with increase of high-density lipoprotein, and reduction of total cholesterol, triglycerides, and low-density lipoprotein cholesterol. Knockdown of Bcl-3 attenuated imiquimod-induced decrease of transforming growth factor beta (TGF-ß), and increase of Interleukin (IL)-17A, IL-23, IL-6, and tumor necrosis factor-α (TNF-α) in ApoE-deficient mice. Protein expression of phospho-Akt (p-Akt) and p-GSK3ß in ApoE-deficient psoriatic mice was decreased by silencing of Bcl-3. CONCLUSION: Loss of Bcl-3 exerted anti-inflammatory effect on psoriasis and dyslipidemia comorbidity through inactivation of Akt/GSK3ß pathway.

The Toll-like receptor agonist imiquimod is metabolized by aryl hydrocarbon receptor-regulated cytochrome P450 enzymes in human keratinocytes and mouse liver.

The Toll-like receptor 7 agonist imiquimod (IMQ) is an approved drug for the topical treatment of various skin diseases that, in addition, is currently tested in multiple clinical trials for the immunotherapy of various types of cancers. As all of these trials include application of IMQ to the skin and evidence exists that exposure to environmental pollutants, i.e., tobacco smoke, affects its therapeutic efficacy, the current study aims to elucidate the cutaneous metabolism of the drug. Treatment of human keratinocytes with 2.5 µM benzo[a]pyrene (BaP), a tobacco smoke constituent and aryl hydrocarbon receptor (AHR) agonist, for 24 h induced cytochrome P450 (CYP) 1A enzyme activity. The addition of IMQ 30 min prior measurement resulted in a dose-dependent inhibition of CYP1A activity, indicating that IMQ is either a substrate or inhibitor of CYP1A isoforms. Incubation of 21 recombinant human CYP enzymes with 0.5 µM IMQ and subsequent LC-MS analyses, in fact, identified CYP1A1 and CYP1A2 as being predominantly responsible for IMQ metabolism. Accordingly, treatment of keratinocytes with BaP accelerated IMQ clearance and the associated formation of monohydroxylated IMQ metabolites. A co-incubation with 5 µM 7-hydroxyflavone, a potent inhibitor of human CYP1A isoforms, abolished basal as well as BaP-induced IMQ metabolism. Further studies with hepatic microsomes from CD-1 as well as solvent- and ß-naphthoflavone-treated CYP1A1/CYP1A2 double knock-out and respective control mice confirmed the critical contribution of CYP1A isoforms to IMQ metabolism. Hence, an exposure to life style-related, dietary, and environmental AHR ligands may affect the pharmacokinetics and, thus, treatment efficacy of IMQ.

Inflammatory and Immunomodulatory Effects of Tripterygium wilfordii Multiglycoside in Mouse Models of Psoriasis Keratinocytes.

OBJECTIVE: To determine the role of Tripterygium wilfordii multiglycoside (TGW) in the treatment of psoriatic dermatitis from a cellular immunological perspective. METHODS: Mouse models of psoriatic dermatitis were established by imiquimod (IMQ). Twelve male BALB/c mice were assigned to IMQ or IMQ+TGW groups according to a random number table. Histopathological changes in vivo were assessed by hematoxylin and eosin staining. Ratios of immune cells and cytokines in mice, as well as PAM212 cell proliferation in vitro were assessed by flow cytometry. Pro-inflammatory cytokine expression was determined using reverse transcription quantitative polymerase chain reaction. RESULTS: TGW significantly ameliorated the severity of IMQ-induced psoriasis-like mouse skin lesions and restrained the activation of CD45+ cells, neutrophils and T lymphocytes (all P<0.01). Moreover, TGW significantly attenuated keratinocytes (KCs) proliferation and downregulated the mRNA levels of inflammatory cytokines including interleukin (IL)-17A, IL-23, tumor necrosis factor α, and chemokine (C-X-C motif) ligand 1 (P<0.01 or P<0.05). Furthermore, it reduced the number of γ δ T17 cells in skin lesion of mice and draining lymph nodes (P<0.01). CONCLUSIONS: TGW improved psoriasis-like inflammation by inhibiting KCs proliferation, as well as the associated immune cells and cytokine expression. It inhibited IL-17 secretion from γ δ T cells, which improved the immune-inflammatory microenvironment of psoriasis.

Enteric Toll-like receptor 7 stimulation causes acute exacerbation in lupus-susceptible mice.

Autoimmune diseases are often accompanied by acute exacerbation. However, the mechanism underlying systemic lupus erythematosus (SLE) flares remains unclear. We investigated whether short-term enteric Toll-like receptor 7 (TLR7) stimulation can exacerbate SLE using B6SKG mice, which spontaneously develop SLE due to a mutation in the zeta‒chain‒associated protein kinase 70 (Zap70) gene. Imiquimod (IMQ) or phosphate-buffered saline (PBS) were orally administered on B6WT and B6SKG mice every other day for 2 weeks. SLE exacerbation was assessed via fluorescent immunohistochemical staining of glomeruli for IgG and C3, hematoxylin and eosin staining of kidneys, and enzyme-linked immunosorbent assay for antinuclear antibody (ANA). Flow cytometry was used to evaluate germinal center B cells (GCBs), plasma cells, follicular helper T cells (Tfhs), regulatory T cells (Tregs), effector T cells (Th1s and Th17s), plasmacytoid dendritic cells (pDCs), conventional dendritic cells (cDCs), and macrophages (Mφs) in spleens. Oral administration of IMQ every other day for 2 weeks resulted in exacerbation of splenomegaly, increased IgG and C3 deposition in glomeruli, and increased ANA production in the B6SKG IMQ (SKG-IMQ) group compared to the B6SKG PBS (SKG-PBS) group; the percentages of GCBs, plasma cells, Tfhs, Th1s, pDCs, and Mφs were also increased in the SKG-IMQ group. Splenomegaly, IgG, and C3 deposition in glomeruli, and the percentages of GCBs, plasma cells, Tfhs, and Th1s were enhanced in SKG-IMQ mice compared with B6SKG mice topically treated with IMQ (SKG-ear-IMQ). Oral TLR7 stimulation in a Zap70 genetic mutation background can cause acute exacerbations of SLE. Key Points • The mechanism of SLE flares is not well understood. • We have created a model that causes short-term SLE exacerbations in mice with a genetic background. • IMQ administered orally causes more SLE in mice than transdermally.

Chemerin Exacerbates Psoriasis by Stimulating Keratinocyte Proliferation and Cytokine Production.

OBJECTIVE: Psoriasis is often combined with metabolic abnormalities, such as obesity and diabetes. The upregulation of chemerin, which is an essential protein produced primarily from white fat, is strongly correlated to the development of psoriasis. However, there is no clarification on its exact function and mechanism in disease pathogenesis. The present study aims to determine its function and mechanism in disease pathogenesis. METHODS: The present study used a psoriasislike inflammatory cell model and imiquimod (IMQ)-induced mouse model to confirm whether chemerin is upregulated in psoriasis patients. RESULTS: Chemerin enhanced the keratinocyte proliferation, inflammatory cytokine secretion, and activation of the MAPK signaling pathway. Crucially, the intraperitoneal injection of neutralizing anti-chemerin antibody (ChAb) diminished the epidermal proliferation and inflammation in the IMQ-induced mouse model. CONCLUSION: The present results indicate that chemerin promotes keratinocyte proliferation, and enhances the production of inflammatory cytokines, thereby aggravating the psoriasis. Thus, chemerin can be a prospective target for the treatment of psoriasis.

Discovery of 3-Phenyl Indazole-Based Novel Chemokine-like Receptor 1 Antagonists for the Treatment of Psoriasis.

Chemokine-like receptor 1 (CMKLR1)─a G protein-coupled receptor─has functional roles in the immune system and related diseases, including psoriasis and metabolic diseases. Psoriasis is a chronic inflammatory disease characterized by skin redness, scaliness, and itching. In this study, we sought to develop novel CMKLR1 antagonists by screening our in-house GPCR-targeting compound library. Moreover, we optimized a phenylindazole-based hit compound with antagonistic activities and evaluated its oral pharmacokinetic properties in a murine model. A structure-based design on the human CMKLR1 homology model identified S-26d as an optimized compound that serves as a potent and orally available antagonist with a pIC50 value of 7.44 in hCMKLR1-transfected CHO cells. Furthermore, in the imiquimod-induced psoriasis-like mouse model, oral administration of S-26d for 1 week significantly alleviated modified psoriasis area and severity index scores (severity of erythema, scaliness, skin thickness) compared with the control group.