Serum Metabolomic Profiling Reveals the Amelioration Effect of Methotrexate on Imiquimod-Induced Psoriasis in Mouse

Cornuside alleviates psoriasis-like skin lesions in mice by relieving inflammatory effects

Psoriasis is a chronic inflammatory skin disease substantially affecting the quality of life, with no complete cure owing to its complex pathogenesis. Cornuside, a major bioactive compound present in Cornus officinalis Sieb. et Zucc., which is a well-known traditional Chinese medicine with a variety of biological and pharmacological activities, such as anti-apoptotic, antioxidant, and anti-inflammatory properties. However, its effects on psoriasis remain unclear. Our preliminary analysis of network pharmacology showed that cornuside may be involved in psoriasis by regulating the inflammatory response and IL-17 signaling pathway. Thus, we investigated the protective role and mechanism of cornuside in the pathogenesis of psoriasis in an imiquimod (IMQ)-induced psoriasis mouse model. In-vivo experiments demonstrated that cornuside-treated mice had reduced skin erythema, scales, thickness, and inflammatory infiltration. The Psoriasis Area Severity Index score was significantly lower than that of the IMQ group. Flow cytometry analysis indicated that cornuside effectively inhibited Th1- and Th17-cell infiltration and promoted aggregation of Th2 cells in skin tissues. Cornuside also inhibited the infiltration of macrophages to the skin. Furthermore, in-vitro experiments indicated that cornuside also decreased the polarization of M1 macrophages and reduced the levels of associated cytokines. Western blotting demonstrated that cornuside suppressed the phosphorylation of c-Jun N-terminal kinase (JNK) and extracellular receptor kinase (ERK) in bone marrow-derived macrophages. Our findings indicate that cornuside has a protective effect against IMQ-induced psoriasis by inhibiting M1 macrophage polarization through the ERK and JNK signaling pathways and modulating the infiltration of immune cells as well as the expression of inflammatory factors.

Energy competition remodels the metabolic glucose landscape of psoriatic epidermal cells

Rationale: Skin cells actively metabolize nutrients to ensure cell proliferation and differentiation. Psoriasis is an immune-disorder-related skin disease with hyperproliferation in epidermal keratinocytes and is increasingly recognized to be associated with metabolic disturbance. However, the metabolic adaptations and underlying mechanisms of epidermal hyperproliferation in psoriatic skin remain largely unknown. Here, we explored the role of metabolic competition in epidermal cell proliferation and differentiation in psoriatic skin. Methods: Bulk- and single-cell RNA-sequencing, spatial transcriptomics, and glucose uptake experiments were used to analyze the metabolic differences in epidermal cells in psoriasis. Functional validation in vivo and in vitro was done using imiquimod-like mouse models and inflammatory organoid models. Results: We observed the highly proliferative basal cells in psoriasis act as the winners of the metabolic competition to uptake glucose from suprabasal cells. Using single-cell metabolic analysis, we found that the "winner cells" promote OXPHOS pathway upregulation by COX7B and lead to increased ROS through glucose metabolism, thereby promoting the hyperproliferation of basal cells in psoriasis. Also, to prevent toxic damage from ROS, basal cells activate the glutathione metabolic pathway to increase their antioxidant capacity to assist in psoriasis progression. We further found that COX7B promotes psoriasis development by modulating the activity of the PPAR signaling pathway by bulk RNA-seq analysis. We also observed glucose starvation and high expression of SLC7A11 that causes suprabasal cell disulfide stress and affects the actin cytoskeleton, leading to immature differentiation of suprabasal cells in psoriatic skin. Conclusion: Our study demonstrates the essential role of cellular metabolic competition for skin tissue homeostasis.

Metabolomics analysis reveals cytotoxic effects of ouabain towards psoriatic keratinocytes via impairment of glutathione metabolism

Ouabain is a cardiac glycoside long studied for treating heart diseases, but the attempts to evaluate its anti-psoriatic activity have not been reported. We aimed to explore the effects of ouabain on proliferation and metabolism towards psoriatic keratinocytes. In human HaCaT keratinocytes, ouabain potently decreased viability, promoted apoptosis and caused G2/M cycle arrest. Metabolomics analysis indicated that ouabain markedly impaired glutathione metabolism. The solute carrier family 7 member 11 (SLC7A11) is an amino acid transporter highly specific to cysteine, which is critical for glutathione synthesis. Ouabain downregulated SLC7A11, reduced cysteine uptake and subsequently inhibited glutathione synthesis, probably through inhibiting Akt/mTOR/beclin axis that regulate protein activity of SLC7A11. The impaired glutathione synthesis and oxidative stress caused by ouabain may contribute to its cytotoxicity towards psoriatic keratinocytes. Our results provide experimental evidence supporting further study of ouabain as a potential anti-psoriatic agent.

Modulation of Skin Inflammatory Responses by Aluminum Adjuvant

Aluminum salt (AS), one of the most commonly used vaccine adjuvants, has immuno-modulatory activity, but how the administration of AS alone may impact the activation of the skin immune system under inflammatory conditions has not been investigated. Here, we studied the therapeutic effect of AS injection on two distinct skin inflammatory mouse models: an imiquimod (IMQ)-induced psoriasis-like model and an MC903 (calcipotriol)-induced atopic dermatitis-like model. We found that injection of a high dose of AS not only suppressed the IMQ-mediated development of T-helper 1 (Th1) and T-helper 17 (Th17) immune responses but also inhibited the IMQ-mediated recruitment and/or activation of neutrophils and macrophages. In contrast, AS injection enhanced MC903-mediated development of the T-helper 2 (Th2) immune response and neutrophil recruitment. Using an in vitro approach, we found that AS treatment inhibited Th1 but promoted Th2 polarization of primary lymphocytes, and inhibited activation of peritoneal macrophages but not bone marrow derived neutrophils. Together, our results suggest that the injection of a high dose of AS may inhibit Th1 and Th17 immune response-driven skin inflammation but promote type 2 immune response-driven skin inflammation. These results may provide a better understanding of how vaccination with an aluminum adjuvant alters the skin immune response to external insults.

Potential shared therapeutic and hepatotoxic mechanisms of Tripterygium wilfordii polyglycosides treating three kinds of autoimmune skin diseases by regulating IL-17 signaling pathway and Th17 cell differentiation

ETHNOPHARMACOLOGICAL RELEVANCE

Tripterygium wilfordii polyglycosides (TWP) are extracted from Tripterygium wilfordii Hook. f., which has the significant effects of anti-inflammation and immunosuppression and has been widely used to treat autoimmune diseases in traditional Chinese medicine.

AIM OF STUDY

In Chinese clinical dermatology, TWP was generally used for the treatment of autoimmune skin diseases including psoriasis (PSO), systemic lupus erythematosus (SLE) and pemphigus (PEM). However, the potential hepatotoxicity (HPT) induced by TWP was also existing with the long-term use of TWP. This study aims to explore the potential shared therapeutic mechanism of TWP treating PSO, SLE, PEM and the possible hepatotoxic mechanism induced by TWP.

MATERIALS AND METHODS

Network pharmacology was used to predict the potential targets and pathways in this study. The main bioactive compounds in TWP was screened according to TCMSP, PubChem, ChEMBL databases and Lipinski's Rule of Five. The potential targets of these chemical constituents were obtained from PharmMapper, SEA and SIB databases. The related targets of PSO, SLE, PEM and HPT were collected from GeneCards, DrugBank, DisGeNET and CTD databases. The target network construction was performed through STRING database and Cytoscape. GO enrichment, KEGG enrichment and molecular docking were then performed, respectively. In particular, imiquimod (IMQ)-induced PSO model was selected as the representative for the experimental verification of effects and shared therapeutic mechanisms of TWP.

RESULTS

41 targets were considered as the potential shared targets of TWP treating PSO, SLE and PEM. KEGG enrichment indicated that IL-17 signaling pathway and Th17 cell differentiation were significant in the potential shared therapeutic mechanism of TWP. The animal experimental verification demonstrated that TWP could notably ameliorate skin lesions (P˂0.001), decrease inflammatory response (P˂0.05, P˂0.01, P˂0.001) and inhibit the differentiation of Th1/Th17 cells (P˂0.05, P˂0.01) compared to PSO model group. The molecular docking and qPCR validation then showed that TWP could effectively act on MAPK14, IL-2, IL-6 and suppress Th17 cell differentiation and IL-17 signaling pathway. The possible hepatotoxic mechanism of TWP indicated that there were 145 hepatotoxic targets and it was also associated with IL-17 signaling pathway and Th17 cell differentiation, especially for the key role of ALB, CASP3 and HSP90AA1. Meanwhile, the potential correlations between efficacy and hepatotoxicity of TWP showed that 28 targets were shared by therapeutic and hepatotoxic mechanisms such as IL-6, IL-2, MAPK14, MMP9, ALB, CASP3 and HSP90AA1. These significant relevant targets were also involved in IL-17 signaling pathway and Th17 cell differentiation.

CONCLUSIONS

There were shared disease targets in PSO, SLE and PEM, and TWP could treat them by potential shared therapeutic mechanisms of suppressing IL-17 signaling pathway and Th17 cell differentiation. The possible hepatotoxicity induced by TWP was also significantly associated with the regulation of IL-17 signaling pathway and Th17 cell differentiation. Meanwhile, the potential correlations between efficacy and hepatotoxicity of TWP also mainly focused on IL-17 signaling pathway and Th17 cell differentiation, which provided a potential direction for the study of the mechanism of "You Gu Wu Yun" theory of TWP treating autoimmune skin diseases in the future.

Chlorquinaldol inhibits the activation of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3 inflammasome and ameliorates imiquimod-induced psoriasis-like dermatitis in mice

Psoriasis is a common chronic autoinflammatory/autoimmune skin disease associated with elevated pro-inflammatory cytokines. The pivotal role of interleukin (IL)-1β and nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome in the pathogenesis of psoriasis has been widely described. Accordingly, the suppression of NLRP3-dependent IL-1β release is a potential therapy for psoriasis. Repurposing marketed drugs is a strategy for identifying new inhibitors of NLRP3 inflammasome activation. Herein, chlorquinaldol (CQD), a historic antimicrobial agent used as a topical treatment for skin and vaginal infections, was found to have a distinct effect by inhibiting NLRP3 inflammasome activation at concentrations ranging from 2 to 6 μM. CQD significantly suppressed apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) oligomerization, NLRP3-ASC interaction, and pyroptosis in macrophages. The levels of cleaved IL-1β and caspase-1 were reduced by CQD in the cell lysates of macrophages, suggesting that CQD acted on upstream of pore formation in the cell membrane. Mechanistically, CQD reduced mitochondrial reactive oxygen species production but did not affect the nuclear factor-κB (NF-κB) pathway. Intraperitoneal administration of CQD (15 mg/kg) for 6 days was found to improve the skin lesions in the imiquimod-induced psoriatic mouse model (male C57BL/6 mice), while secretion of pro-inflammatory cytokines (IL-17 and IL-1β) and keratinocyte proliferation were significantly suppressed by CQD. In conclusion, CQD exerted inhibitory effects on NLRP3 inflammasome activation in macrophages and decreased the severity of psoriatic response in vivo. Such findings indicate that the repurposing of the old drug, CQD, is a potential pharmacological approach for the treatment of psoriasis and other NLRP3-driven diseases.

Potential mechanism of oral baicalin treating psoriasis via suppressing Wnt signaling pathway and inhibiting Th17/IL-17 axis by activating PPARγ

Psoriasis (PSO), an immune-mediated chronic inflammatory skin disease, has seriously affected the quality of patients' life. It is urgent to find effective medicines with lower costs and less side effects. Baicalin (HQG) is the main bioactive substance from Scutellaria baicalensis with effects of anti-inflammation and immunoregulation. Herein, we explored the effect of oral HQG treating PSO and its potential mechanism. Firstly, network pharmacology was used to predict that HQG may act on Estrogen, TNF-alpha (tumor necrosis factor, TNF), interleukin-17 (IL-17) signaling pathways and Th17 cell differentiation, especially the key targets including TNF, Proto-oncogene tyrosine-protein kinase Src, Peroxisome proliferator-activated receptor gamma and Matrix metalloproteinase-9. Imiquimod (IMQ)-induced mice were then used to study the effects of HQG treating PSO. HQG could significantly ameliorate the skin lesions, decrease the level of inflammatory factors and inhibit Th1/Th17 cell differentiation in IMQ-induced mice. Finally, transcriptome analysis of skin lesions integrated with the prediction of network pharmacology further demonstrated that the potential mechanism may be associated with suppressing Wnt signaling pathway and inhibiting Th17/IL-17 axis by activating PPARγ. In conclusion, this study suggested that HQG may be a promising agent for further studies in the search for therapeutic strategies to treat PSO in the future.

Design and synthesis of the 4H-chromenone derivatives against psoriasis

On basis of Quercetin moiety, two series of 20 new compounds were designed and synthesized accordingly in this study, and their anti-inflammatory activities in vitro and in vivo were evaluated. At last, compound 8A2: 3- (1- (2- (4- (5-bromo-2-chlorobenzoyl) piperazin-1-yl) ethyl)-1H-1,2,3-triazol-4-yl) methoxy)-5,7-dimethoxy-2-(3,4,5-trimethoxyphenyl)-4H-chromen-4-one with low toxicity was found the best one for inhibiting of NO. Meanwhile, this compound could significantly inhibit the expression of IL-6 (Interleukin-6), TNF-α (Tumor necrosis factor-α) and IL-17 (Interleukin-17), and also significantly down-regulate IL-17 mRNA psoriasis model in vitro. Further studies were performed to establish mouse psoriasis model induced by Imiquimod (IMQ), and the preliminary mechanism indicated that compound 8A2 may alleviate mouse psoriasis through obstructed the JAK1/2-STAT1/3 pathway. This study should be provide a basis for further study of effective treatment of psoriasis.

Integrated Metabolomics and Transcriptomics Analyses Reveal Histidine Metabolism Plays an Important Role in Imiquimod-Induced Psoriasis-like Skin Inflammation

Psoriasis is a chronic inflammatory skin disease characterized by massive keratinocyte proliferation and immune cell infiltration into the epidermis. However, the specific mechanisms underlying the development of psoriasis remain unclear. Untargeted metabolomics and transcriptomics have been used separately to profile biomarkers and risk genes in the serum of psoriasis patients. However, the integration of metabolomics and transcriptomics to identify dysregulated metabolites and genes in the psoriatic skin is lacking. In this study, we performed an untargeted metabolomics analysis of imiquimod (IMQ)-induced psoriasis-like mice and healthy controls, and found that levels of a total of 4,188 metabolites differed in IMQ-induced psoriasis-like mice compared with those in control mice. Metabolomic data analysis using MetaboAnalyst showed that the metabolic pathways of primary metabolites, such as folate biosynthesis and galactose metabolism, were significantly altered in the skin of mice after treatment with IMQ. Furthermore, IMQ treatment also significantly altered metabolic pathways of secondary metabolites, including histidine metabolism, in mouse skin tissues. The metabolomic results were verified by transcriptomics analysis. RNA-seq results showed that histamine decarboxylase (HDC) mRNA levels were significantly upregulated after IMQ treatment. Targeted inhibition of histamine biosynthesis process using HDC-specific inhibitor, pinocembrin (PINO), significantly alleviated epidermal thickness, downregulated the expression of interleukin (IL)-17A and IL-23, and inhibited the infiltration of immune cells during IMQ-induced psoriasis-like skin inflammation. In conclusion, our study offers a validated and comprehensive understanding of metabolism during the development of psoriasis and demonstrated that PINO could protect against IMQ-induced psoriasis-like skin inflammation.

Large-scale plasma-metabolome analysis identifies potential biomarkers of psoriasis and its clinical subtypes

BACKGROUND

Psoriasis is an immune-mediated skin disease for which the crosstalk between genetic and environmental factors is responsible. To date, no definitive diagnostic criteria for psoriasis yet, and specific biomarkers are required.

OBJECTIVE

We performed metabolome analysis to identify metabolite biomarkers of psoriasis and its subtypes such as psoriatic arthritis (PsA) and cutaneous psoriasis (PsC).

METHODS

We constructed metabolomics profiling of 130 plasma samples (42 PsA patients, 50 PsC patients, and 38 healthy controls) using a nontargeted metabolomics approach.

RESULTS

Psoriasis-control association tests showed that one metabolite (ethanolamine phosphate) was significantly increased in psoriasis samples than in the controls, whereas three metabolites decreased (false discovery rate [FDR] < 0.05; XA0019, nicotinic acid, and 20α-hydroxyprogesterone). In the association test between PsA and PsC, tyramine significantly increased in PsA than in PsC, whereas mucic acid decreased (FDR < 0.05). Molecular pathway analysis of the PsA-PsC association test identified enrichment of vitamin digestion and absorption pathway in PsC (P = 1.3 × 10^-4). Correlation network analyses elucidated that a subnetwork centered on aspartate was constructed among the psoriasis-associated metabolites; meanwhile, the major subnetwork among metabolites with differences between PsA and PsC was primarily formed from saturated fatty acids.

CONCLUSION

Our large-scale metabolome analysis highlights novel characteristics of plasma metabolites in psoriasis and the differences between PsA and PsC, which could be used as potential biomarkers of psoriasis and its clinical subtypes. These findings contribute to our understanding of psoriasis pathophysiology.