Potentiation of Psoriasis-Like Inflammation by PCSK9.
ABSTRACT: Psoriasis is a systemic inflammatory disease, associated with metabolic disorders, including high level of low-density lipoprotein. PCSK9, which promotes the degradation of low-density lipoprotein receptors and, therefore, the increased concentration of circulating low-density lipoprotein, is also involved in inflammation. This study aims to examine the role of PCSK9 in psoriasis and to investigate the potential of topically applying small interfering RNA targeting Pcsk9 as a psoriasis treatment. We investigated the expression of PCSK9 in lesions of psoriasis patients and imiquimod-induced psoriatic reactions in Pcsk9-knockout and Pcsk9 small interfering RNA-treated mice, and we also used cultured human keratinocytes to investigate the role of PCSK9 in regulating cell proliferation and apoptosis. We found that PCSK9 is overexpressed in psoriatic lesions and that suppressing Pcsk9 can decrease the inflammatory reaction induced by imiquimod treatment and inhibit hyperproliferation of keratinocytes. We also found that suppressing PCSK9 can significantly alter the cell cycle and induce apoptosis of human keratinocytes. Taken together, our findings indicate that PCSK9 plays an important role in psoriasis and may be a therapeutic target.
Project description:Psoriasis is a chronic skin disease characterized by hyperproliferation and impaired differentiation of epidermal keratinocytes accompanied by increased inflammation, suggesting that molecules with antiproliferation and anti-inflammatory abilities may be effective for its treatment. One of the key steps in regulating cell proliferation is DNA replication initiation, which relies on prereplication complex (pre-RC) assembly on chromatin. CDC6 is an essential regulator of pre-RC assembly and DNA replication in eukaryotic cells, but its role in proliferation of keratinocytes and psoriasis is unknown. Here we examined CDC6 expression in psoriatic skin and evaluated its function in the proliferation of human keratinocytes. CDC6 expression is upregulated in epidermal cells in psoriatic lesions and it could be induced by IL-22/STAT3 signaling, a key signaling pathway involved in the pathogenesis of psoriasis, in keratinocytes. Depletion of CDC6 leads to decreased proliferation of keratinocytes. We also revealed that berberine (BBR) could inhibit CDK4/6-RB-CDC6 signaling in keratinocytes, leading to reduced proliferation of keratinocytes. The mechanism of antiproliferation effects of BBR is through the repression of JAK1, JAK2, and TYK2, which in turn inhibits activation of STAT3. Finally, we demonstrated that BBR could inhibit imiquimod-induced psoriasis-like skin lesions and upregulation of CDC6 and p-STAT3 in mice. Collectively, our findings indicate that BBR inhibits CDC6 expression and proliferation in human keratinocytes by interfering the JAK-STAT3 signaling pathway. Thus, BBR may serve as a potential therapeutic option for patients with psoriasis.
Project description:The transcriptional activator I?B? is a key regulator of psoriasis, but which cells mediate its pathogenic effect remains unknown. Here we found that I?B? expression in keratinocytes triggers not only skin lesions but also systemic inflammation in mouse psoriasis models. Specific depletion of I?B? in keratinocytes was sufficient to suppress the induction of imiquimod- or IL-36-mediated psoriasis. Moreover, I?B? ablation in keratinocytes prevented the onset of psoriatic lesions and systemic inflammation in keratinocyte-specific IL-17A-transgenic mice. Mechanistically, this psoriasis protection was mediated by I?B? deficiency in keratinocytes abrogating the induction of specific proinflammatory target genes, including Cxcl5, Cxcl2, Csf2, and Csf3, in response to IL-17A or IL-36. These I?B?-dependent genes trigger the generation and recruitment of neutrophils and monocytes that are needed for skin inflammation. Consequently, our data uncover a surprisingly pivotal role of keratinocytes and keratinocyte-derived I?B? as key mediators of psoriasis and psoriasis-related systemic inflammation.
Project description:SLURP1 is the causal gene for Mal de Meleda (MDM), an autosomal recessive skin disorder characterized by diffuse palmoplantar keratoderma and transgressive keratosis. Moreover, although SLURP1 likely serves as an important proliferation/differentiation factor in keratinocytes, the possible relation between SLURP1 and other skin diseases, such as psoriasis and atopic dermatitis, has not been studied, and the pathophysiological control of SLURP1 expression in keratinocytes is largely unknown.Our aim was to examine the involvement of SLURP1 in the pathophysiology of psoriasis using an imiquimod (IMQ)-induced psoriasis model mice and normal human epidermal keratinocytes (NHEKs).SLURP1 expression was up-regulated in the skin of IMQ-induced psoriasis model mice. In NHEKs stimulated with the inflammatory cytokines IL-17, IL-22 and TNF-?, which are reportedly expressed in psoriatic lesions, SLURP1 mRNA expression was significantly up-regulated by IL-22 but not the other two cytokines. The stimulatory effect of IL-22 was completely suppressed in NHEKs treated with a STAT3 inhibitor or transfected with siRNA targeting STAT3. Because IL-22 induces production of antimicrobial proteins in epithelial cells, the antibacterial activity of SLURP1 was assessed against Staphylococcus aureus (S. aureus), which is known to be associated with disease severity in psoriasis. SLURP1 significantly suppressed the growth of S. aureus.These results indicate SLURP1 participates in pathophysiology of psoriasis by regulating keratinocyte proliferation and differentiation, and by suppressing the growth of S. aureus.
Project description:OBJECTIVE:Psoriasis is a chronic inflammatory skin disease and topical therapy remains a key role for treatment. The aim of this study is to evaluate the influence of psoriasis-like lesions on the cutaneous permeation of anti-psoriatic drugs. METHODS:We first set up imiquimod-induced dermatitis in mice that closely resembles human psoriasis lesions. The development of the lesions is based on the IL-23/IL17A axis for phenotypical and histological characteristics. Four drugs, 5-aminolevulinic acid (ALA), tacrolimus, calcipotriol, and retinoic acid, were used to evaluate percutaneous absorption. RESULTS:The most hydrophilic molecule, ALA, revealed the greatest enhancement on skin absorption after imiquimod treatment. Imiquimod increased the skin deposition and flux of ALA by 5.6 to 14.4-fold, respectively, compared to normal skin. The follicular accumulation of ALA was also increased 3.8-fold. The extremely lipophilic drug retinoic acid showed a 1.7- and 3.8-fold increase in skin deposition and flux, respectively. Tacrolimus flux was enhanced from 2 to 21 ?g/cm2/h by imiquimod intervention. However, imiquimod did not promote skin deposition of this macrolide. The lipophilicity, but not the molecular size, dominated drug permeation enhancement by psoriatic lesions. The in vivo percutaneous absorption of ALA and rhodamine B examined by confocal microscopy confirmed the deficient resistance of epidermal barrier for facilitating cutaneous delivery of drugs via psoriasis-like skin. CONCLUSION:We established the topical delivery profiles of anti-psoriatic drugs via imiquimod-treated psoriasis-like skin.
Project description:BACKGROUND:Proprotein convertase subtilisin/kexin type 9 (PCSK9) exerts an important role in inflammatory processes, lipids homeostasis, and cardiometabolic disorders that are closely associated with psoriasis. The aim of the study was to analyze the clinical and diagnostic value of serum PCSK9 concentrations and their connections with disease severity, inflammation, metabolic syndrome, and impact of systemic therapies in psoriatic patients. The study enrolled thirty-five patients with active plaque-type psoriasis and eighteen healthy volunteers served as controls. Blood samples were obtained before and after 12 weeks of treatment with methotrexate or acitretin. Serum PCSK9 concentrations were measured by the ELISA (Enzyme-Linked Immunosorbent Assay) commercial kits. Morphological and biochemical parameters were assayed using routine laboratory techniques. Psoriatic patients showed significantly elevated levels of PCSK9 compared to controls (p < 0.01), mostly in patients with a mild and moderate course of psoriasis. PCSK9 concentrations correlated positively with BMI and triglyceride levels (p < 0.05). Interestingly, PCSK9 had a strong negative correlation with low-density lipoprotein levels and total cholesterol (p < 0.05). Three months of monotherapy with methotrexate significantly reduced PCSK9 level (p < 0.05), on the contrary, the acitretin group showed a further increase of PCSK9 levels (p < 0.05). PCSK9 seems to be a novel marker of psoriasis and a putative explanation of lipid disturbances, which are common in patients with psoriasis and are vital for the further developing of metabolic syndrome. Methotrexate should be considered as a treatment of choice in patients with an elevated PCSK9 concentration.
Project description:OBJECTIVES:IFI27 is highly expressed in psoriatic lesions but its function has not been known. The present study aimed to explore its role in proliferation of epidermal keratinocytes. MATERIALS AND METHODS:IFI27 knockdown and over-expression in keratinocytes were used to compare their proliferation, by MTT assay, apoptosis (by annexin V binding) and cell cycle progression by flow cytometry. Formation of cyclin A/CDK1 complex was examined by a co-immunoprecipitaion method. Anti-proliferation effects of IFI27 were also examined in vivo by topical application of IFI27 siRNA on imiquimod-induced psoriatic lesions, in a mouse model. RESULTS:Epidermal growth factor was demonstrated to increase IFI27 expression by prolonging half-life of IFI27 protein. The IFI27 knockdown in keratinocytes reduced the proliferation rate, but had no effect on apoptosis nor on apoptosis-related genes. Interestingly, IFI27 knockdown resulted in S-phase arrest that was found to be associated with increased Tyr15 phosphorylation of CDK1, reduced CDC25B and reduced formation of cyclin A/CDK1 complex. In addition, IFI27 knockdown was also shown to activate p53 by Ser15 phosphorylation and increase p21 expression. Topical application of IFI27 siRNA on imiquimod-induced psoriatic lesion in a mouse model reduced epidermal thickness, formation of rete ridges and PCNA expression. CONCLUSIONS:Our study demonstrates for the first time, that cell function of IFI27 is involved in proliferation of skin keratinocytes both in vitro and in vivo. It suggests that IFI27 might be a suitable target for development of a novel anti-psoriasis therapy.
Project description:Epithelial keratinocyte proliferation is an essential element of wound repair, and abnormal epithelial proliferation is an intrinsic element in the skin disorder psoriasis. The factors that trigger epithelial proliferation in these inflammatory processes are incompletely understood. Here we have shown that regenerating islet-derived protein 3-alpha (REG3A) is highly expressed in keratinocytes during psoriasis and wound repair and in imiquimod-induced psoriatic skin lesions. The expression of REG3A by keratinocytes is induced by interleukin-17 (IL-17) via activation of keratinocyte-encoded IL-17 receptor A (IL-17RA) and feeds back on keratinocytes to inhibit terminal differentiation and increase cell proliferation by binding to exostosin-like 3 (EXTL3) followed by activation of phosphatidylinositol 3 kinase (PI3K) and the kinase AKT. These findings reveal that REG3A, a secreted intestinal antimicrobial protein, can promote skin keratinocyte proliferation and can be induced by IL-17. This observation suggests that REG3A may mediate the epidermal hyperproliferation observed in normal wound repair and in psoriasis.
Project description:Background:Psoriasis is a pro-inflammatory disease with unknown etiology, that is characterized by skin inflammation and keratinocytes hyperproliferation. Specific inhibition of inflammation has shown positive effects avoiding the progression of the psoriatic lesions in different animal models of the disease, turning this strategy as a remarkable therapeutic alternative. Objective:To screen the effectiveness of a novel IFN-?/? signalling inhibitor in the development reduction of skin lesions in IMQ and TPA mice models of psoriasis. Methods:We used a Phage-peptide library for the screening of a peptide with inhibitory effects on the development of psoriasis-like lesions in mice. To evaluate the in vivo effect of the phage-peptides (Phpep3D) and the derived peptide (Pep3D), we administered Phpep3D or Pep3D intradermally in mice with imiquimod (IMQ)-induced psoriasis and 12-O-tetradecanoyl phorbol-13-acetate (TPA)-induced psoriasis. We scored the lesions, and we determined the number of neutrophils and the production of some pro-inflammatory cytokines in the lesions. Results:In this work, we describe how the Ph3pepD and Pep3D reduced skin thickness, redness, and acanthosis despite the presence of the psoriasis inducers, IMQ or TPA. We also found that Pep3D reduced the number of GR1+ infiltrated cells and decreased the production of IL-17A and TNF? in the psoriatic skin of mice. In-silico, docking analysis showed that Pep3D may interact with the interferon-alpha receptor, but further analyses should be performed to uncover the mechanism of action of this peptide. Conclusion:Our results suggest that Pep3D could be used as a new treatment for psoriasis.
Project description:Psoriasis is characterized by keratinocyte hyperproliferation. While significant progress has been made in understanding the molecular mechanism regulating the proliferation of keratinocytes, little is known about the epigenetic factors that control this process. EZH2 and EZH2 mediated trimethylation of histone H3 lysine 27 (H3K27me3) was previously shown ectopically expressed in carcinoma and mediated proliferation, thereby we sought to clarify the role of EZH2-H3K27me3 in the proliferation of psoriatic keratinocyte. Interestingly, we found that EZH2 and H3K27me3 were both overexpressed in the epidermis of psoriatic lesional skin compared to normal skin. In vitro, the expression of EZH2 and H3K27me3 was stimulated in human keratinocytes treated with mixture of psoriasis-related cytokines pool (TNF-?, IFN-?, IL-17A, and IL-22). Knockdown of EZH2 significantly reduced keratinocyte proliferative activity. Results from mRNA microarray analysis suggested that Kallikrein-8 (KLK8) might be the target gene of EZH2 in psoriatic keratinocytes. Overexpression or knockdown KLK8 could partially reverse the abnormal proliferation of keratinocytes caused by knockdown or overexpression of EZH2. In vivo, the inhibitor of EZH2, GSK126 could ameliorate the imiquimod-induced psoriasiform lesion. These results suggest that EZH2 might be a therapeutic target for the treatment of psoriasis.
Project description:Despite the introduction of biologics, topical dithranol (anthralin) has remained one of the most effective anti-psoriatic agents. Serial biopsies from human psoriatic lesions and both the c-Jun/JunB and imiquimod psoriasis mouse model allowed us to study the therapeutic mechanism of this drug. Top differentially expressed genes in the early response to dithranol belonged to keratinocyte and epidermal differentiation pathways and IL-1 family members (i.e. IL36RN) but not elements of the IL-17/IL-23 axis. In human psoriatic response to dithranol, rapid decrease in expression of keratinocyte differentiation regulators (e.g. involucrin, SERPINB7 and SERPINB13), antimicrobial peptides (e.g. ß-defensins like DEFB4A, DEFB4B, DEFB103A, S100 proteins like S100A7, S100A12), chemotactic factors for neutrophils (e.g. CXCL5, CXCL8) and neutrophilic infiltration was followed with much delay by reduction in T cell infiltration. Targeting keratinocytes rather than immune cells may be an alternative approach in particular for topical anti-psoriatic treatment, an area with high need for new drugs.