Epidermal autonomous VEGFA/Flt1/Nrp1 functions mediate psoriasis-like disease

Targeted siRNA Therapy for Psoriasis: Translating Preclinical Potential into Clinical Treatments

Psoriasis is a chronic inflammatory skin disease characterized by the excessive proliferation of keratinocytes and heightened immune activation. Targeting pathogenic genes through small interfering RNA (siRNA) therapy represents a promising strategy for the treatment of psoriasis. This mini-review provides a comprehensive summary of siRNA research targeting the pathogenesis of psoriasis, covering aspects such as keratinocyte function, inflammatory cell roles, preclinical animal studies, and siRNA delivery mechanisms. It details recent advancements in RNA interference that modulate key factors including keratinocyte proliferation (Fibroblast Growth Factor Receptor 2, FGFR2), apoptosis (Interferon Alpha Inducible Protein 6, G1P3), differentiation (Grainyhead Like Transcription Factor 2, GRHL2), and angiogenesis (Vascular Endothelial Growth Factor, VEGF); immune cell infiltration and inflammation (Tumor Necrosis Factor-Alpha, TNF-α; Interleukin-17, IL-17); and signaling pathways (JAK-STAT, Nuclear Factor Kappa B, NF-κB) that govern immunopathology. Despite significant advances in siRNA-targeted treatments for psoriasis, several challenges persist. Continued scientific developments promise the creation of more effective and safer siRNA medications, potentially enhancing the quality of life for psoriasis patients and revolutionizing treatments for other diseases. This article focuses on the most recent research advancements in targeting the pathogenesis of psoriasis with siRNA and explores its future therapeutic prospects.

FOSL1 regulates hyperproliferation and NLRP3-mediated inflammation of psoriatic keratinocytes through the NF-kB signaling via transcriptionally activating TRAF3

Psoriasis is a common and immune-mediated skin disease related to keratinocytes hyperproliferation and inflammation. Fos-like antigen-1 (FOSL1) is an important transcription factor involved in various diseases. FOSL1 has been reported to be differentially expressed in psoriasis. However, the roles and mechanism of FOSL1 in psoriasis progression remain largely unknown. FOSL1 is an upregulated transcription factor in psoriasis and increased in M5-treated HaCaT cells. FOSL1 had a diagnostic value in psoriasis, and positively associated with PASI score, TNF-α and IL-6 levels in psoriasis patients. FOSL1 silencing attenuated M5-induced HaCaT cell hyperproliferation through decreasing cell viability and proliferative ability and increasing cell apoptosis. FOSL1 knockdown mitigated M5-induced NLRP3 inflammasome activation and it-mediated inflammatory cytokine (IL-6, IL-8 and CCL17) expression. TRAF3 expression was increased in psoriasis patients and M5-treated HaCaT cells. FOSL1 transcriptionally activating TRAF3 in HaCaT cells. TRAF3 overexpression reversed the suppressive effects of FOSL1 silencing on M5-induced hyperproliferation and NLRP3-mediated inflammation. FOSL1 knockdown attenuated M5-induced NF-κB signaling activation by reducing TRAF3. Activation of NF-κB signaling reversed the effects of FOSL1 knockdown on hyperproliferation and inflammation in M5-treated cells. FOSL1 silencing prevented M5-induced hyperproliferation and NLRP3-mediated inflammation of keratinocytes by inhibiting TRAF3-mediated NF-κB activity, indicating FOSL1 might act as a therapeutic target of psoriasis.

Sclerotic-Type Cutaneous Chronic Graft-Versus-Host Disease Exhibits Activation of T Helper 1 and OX40 Cytokines

Sclerotic-type cutaneous chronic graft-versus-host disease is a severe complication of allogeneic hematopoietic stem cell transplantation, with profound morbidity. A dearth of effective, targeted treatment options necessitates further investigation into the molecular mechanisms underlying this T-cell-mediated disease. In this study, we compared the transcriptome in skin biopsies from pediatric and young adult (aged <25 years) patients with sclerotic-type cutaneous chronic graft-versus-host disease (n = 7) with that in demographically matched healthy controls (n = 8) and patients with atopic dermatitis (n = 10) using RNA sequencing with RT-PCR and immunohistochemistry validation. Differential expression was defined as fold change > 1.5 and false discovery rate < 0.05. Sclerotic-type cutaneous chronic graft-versus-host disease exhibited strong and significant T helper (Th)1 skewing through key related cytokines and chemokines (CXCL9/10/11, IFNG/IFN-γ, STAT1/signal transducer and activator of transcription 1). Several markers related to the TSLP-OX40 axis were significantly upregulated relative to those in both controls and lesional atopic dermatitis, including TNFSF4/OX40L, TSLP, and IL33, as well as fibroinflammatory signatures characterized in a prior study in systemic sclerosis. Gene set variation analysis reflected marker-level findings, showing the greatest enrichment of the Th1 and fibroinflammatory pathways, with no global activation identified in Th2 or Th17/Th22. Cell-type deconvolution revealed a significant representation of macrophages and vascular endothelial cells. Sclerotic-type cutaneous chronic graft-versus-host disease in young patients may therefore be characterized by strong Th1-related upregulation with a unique TSLP-OX40 signature, suggesting new therapeutic avenues for this devastating disease.

Molecular basis of VEGFR1 autoinhibition at the plasma membrane

Ligand-independent activation of VEGFRs is a hallmark of diabetes and several cancers. Like EGFR, VEGFR2 is activated spontaneously at high receptor concentrations. VEGFR1, on the other hand, remains constitutively inactive in the unligated state, making it an exception among VEGFRs. Ligand stimulation transiently phosphorylates VEGFR1 and induces weak kinase activation in endothelial cells. Recent studies, however, suggest that VEGFR1 signaling is indispensable in regulating various physiological or pathological events. The reason why VEGFR1 is regulated differently from other VEGFRs remains unknown. Here, we elucidate a mechanism of juxtamembrane inhibition that shifts the equilibrium of VEGFR1 towards the inactive state, rendering it an inefficient kinase. The juxtamembrane inhibition of VEGFR1 suppresses its basal phosphorylation even at high receptor concentrations and transiently stabilizes tyrosine phosphorylation after ligand stimulation. We conclude that a subtle imbalance in phosphatase activation or removing juxtamembrane inhibition is sufficient to induce ligand-independent activation of VEGFR1 and sustain tyrosine phosphorylation.

IL-21 promoting angiogenesis contributes to the development of psoriasis

BACKGROUND

Elevated IL-21 expression which can effectively induce Th17 cell differentiation has been implicated in the pathogenesis of psoriasis, but its role in angiogenesis remains poorly understood.

METHODS

PASI and PSI score assessment was applied to evaluate the severity of psoriatic lesions. The expression of IL-21, IL-21 receptor (IL-21R), CD31, VEGFA, MMP-9, and ICAM-1 in skin was determined by immunohistochemistry or quantitative real-time polymerase chain reaction. The serum level of IL-21 was measured by enzyme-linked immunosorbent assay (ELISA). Then, their correlation was analyzed statistically. Human umbilical vein endothelial cells (HUVECs) cocultured with conditional medium from normal human epidermal keratinocytes (NHEKs) were treated with IL-21 and/or M5 cocktail (mixture of IL-1α, IL-17A, IL-22, TNF-α, and oncostatin M). The migration and tube formation of HUVECs were detected, and the levels of VEGFA, MMP-9, and ICAM-1 in NHEKs were measured by Western blotting or ELISA.

RESULTS

Increased IL-21 and IL-21R expression was observed in psoriatic sera or skin specimens, with IL-21R mainly locating in keratinocytes and IL-21 in immune cells. Pearson analysis showed significantly positive correlation between IL-21/IL-21R and erythema scores/microvessel density in psoriatic lesions. Moreover, the expression of proangiogenic genes, VEGFA, ICAM-1, and MMP-9 was upregulated in skins of psoriasis. Additionally, in M5 microenvironment, migration and tube formation could be magnified in HUVECs using IL-21 pre-treated NHEK medium. Mechanically, the co-stimulation of IL-21 and M5 to NEHKs increased the expression of ICAM-1.

CONCLUSION

IL-21 could regulate keratinocytes to secrete ICAM-1, thereby promoting angiogenesis in psoriasis.

Identification and verification of three autophagy-related genes as potential biomarkers for the diagnosis of psoriasis

Psoriasis vulgaris is the most common form of the four clinical types. However, early diagnosis of psoriasis vulgaris is difficult due to the lack of effective biomarkers. The aim of this study was to screen potential biomarkers for the diagnosis of psoriasis. In our study, we downloaded the original data from GSE30999 and GSE41664, and the autophagy-related genes list from human autophagy database to identify differentially expressed autophagy-related genes (DERAGs) by R software. Then Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed for DERAGs. DERAGs were validated by the other four databases (GSE13355, GSE14905, GSE6710, and GSE55201) to screen biomarkers with high diagnostic value for the early diagnosis of psoriasis vulgaris. Finally, DERAGs were verified in our clinical blood samples by ELISA. A total of 12 DERAGs were identified between 123 paired non-lesional and lesional skin samples from patients with psoriasis vulgaris. GO and KEGG enrichment analysis indicated the TORC2 complex was more enriched and the NOD-like receptor signaling pathway was mostly enriched. Three autophagy-related genes (BIRC5, NAMPT and BCL2) were identified through bioinformatics analysis and verified by ELISA in clinical blood samples. And these genes showed high diagnostic value for the early diagnosis of psoriasis vulgaris. We identified three autophagy-related genes (BIRC5, NAMPT and BCL2) with high diagnostic value for the early diagnosis of psoriasis vulgaris through bioinformatics analysis and clinical samples. Therefore, we proposed that BIRC5, NAMPT and BCL2 may be as potential biomarkers for the early diagnosis of psoriasis vulgaris. In addition, BIRC5, NAMPT and BCL2 may affect the development of psoriasis by regulating autophagy.

Vascular Endothelial Growth Factor A VEGFA Inhibition: An Effective Treatment Strategy for Psoriasis

Psoriasis is an inflammatory skin disease mediated by the immune system and characterized by an inflammatory ring, also known as an epithelial immune microenvironment (EIME). The interaction between the epithelial tissue of the skin and the immune system has a crucial role in the immune cycle of psoriasis. Although the formation of new blood vessels in skin lesions provides energy support for the proliferation of epidermal keratinocytes, the role of angiogenesis in psoriasis has not been extensively studied. Vascular endothelial growth factor A (VEGFA) is a key regulator of angiogenesis that has an important role in the development of psoriasis. VEGFA promotes angiogenesis and directly stimulates epidermal keratinocytes and infiltrating immune cells, thus contributing to the progression of psoriasis. Measuring VEGFA levels to identify angiogenic characteristics in psoriasis patients may be a predictive biomarker for disease severity and response to anti-angiogenic therapy. Clinical data have shown that anti-angiogenic therapy can improve skin lesions in psoriasis patients. Therefore, this study aimed to uncover the underestimated role of blood vessels in psoriasis, explore the relationship between VEGFA and keratinocytes in the EIME, and inspire innovative drug therapies for the treatment of psoriasis.

Identification of differentially methylated genes for severe acne by genome-wide DNA methylation and gene expression analysis

Severe acne is a chronic inflammatory skin condition that is affected by both genetic and environmental factors. DNA methylation is associated with a variety of inflammatory skin diseases, but its role in severe acne is unclear. In this study, we conducted a two-stage epigenome correlation study using 88 blood samples to identify disease-related differential methylation sites. We found close associations between the DNA methylation at 23 differentially methylated sites (DMSs) and severe acne, including PDGFD, ARHGEF10, etc. Further analysis revealed that differentially methylated genes (PARP8 and MAPKAPK2) were also expressed differently between severe acne and health control groups. These findings lead us to speculation that epigenetic mechanisms may play an important role in the pathogenesis of severe acne.

Topical Application of Baicalin Combined with Echinacoside Ameliorates Psoriatic Skin Lesions by Suppressing the Inflammation-Related TNF Signaling Pathway and the Angiogenesis-Related VEGF Signaling Pathway

Baicalin (BAI), the main active component of Scutellaria baicalensis, has significant anti-inflammatory and antibacterial effects. Echinacoside (ECH), an active component from Echinacea purpurea, has significant antiangiogenesis and antioxidant effects. In previous studies, BAI or ECH has been used for some skin inflammation problems by topical treatment. Psoriasis (PSO) is a common inflammatory skin disease with typical features such as excessive inflammatory response and vascular proliferation in skin lesions. Because of the anti-inflammatory effect of BAI and the antiangiogenic activity of ECH, it is proposed that the combination of BAI and ECH can ameliorate psoriatic skin lesions better than a single component. This study aims to explore the effects and potential mechanisms of BAI combined with ECH on imiquimod (IMQ)-induced psoriatic skin lesions by topical treatment. Transcriptome analysis first showed that the TNF signaling pathway and the VEGF signaling pathway were significantly enriched in IMQ-induced psoriatic skin lesions. Topical application of BAI combined with ECH could ameliorate IMQ-induced skin lesions in mice, especially the better effects of B2-E1 (BAI/ECH = 2:1). Network pharmacology analysis and molecular docking indicated that BAI-treated PSO on the skin by regulating the TNF signaling pathway, and ECH treated PSO on the skin by regulating the VEGF signaling pathway. Meanwhile, the ELISA test and the qPCR assay showed that BAI combined with ECH could inhibit the expression of key cytokines and genes related to the TNF signaling pathway and the VEGF signaling pathway. Zebrafish experiments demonstrated the anti-inflammatory and antiangiogenic effects of BAI combined with ECH and revealed the potential mechanisms associated with regulating the inflammation-related TNF signaling pathway and the angiogenesis-related VEGF signaling pathway. This suggested that BAI combined with ECH may be a promising topical agent to ameliorate psoriatic skin lesions in the future.

The Future Landscape of Endothelial Cells Research in Psoriasis: Bibliometric Analysis and Literature Review

Background

Psoriasis is a global health concern as a chronic inflammatory skin disease. Endothelial dysfunction has been implicated in psoriasis pathogenesis.

Objective

This study aims to explore the scientific literature on the relationship between psoriasis and endothelial cells using bibliometric analysis, identifying research trends and public interest in this topic.

Methods

We analyzed articles on the topic of endothelial cells and psoriasis in the Web of Science (WoS) Core Collection from 1987 to 2022, examining their distribution by publication year, country, organization, author, and journal. We used bibliometric software, including CiteSpace and R package bibliometrix, to visualize co-authorship relations, keyword citation burst analysis, co citation networks, keyword time zone map, burst references and cluster analysis.

Results

Our analysis included 993 publications. The bibliometric analysis revealed a steady increase in the number of publications on psoriasis and endothelial cells over the past decade. The United States was the leading contributor to this field. The Journal of Investigative Dermatology was the most high-yield publication journal. Burst references analysis identified key articles that have significantly influenced the field, including studies on the role of endothelial dysfunction in psoriasis pathogenesis and the association between psoriasis severity and cardiovascular outcomes. 9 clusters were grouped in the key-word citation network. "Expression", "inflammation", "endothelial growth factor" and "angiogenesis" were the research focuses, while "cardiovascular disease", "atherosclerosis", "endothelial dysfunction", and "oxidative stress" might be the future research hotspots.

Conclusion

This bibliometric analysis sheds light on the growing acknowledgement of the involvement of endothelial cells in psoriasis, with the United States taking the lead. It also emphasizes the necessity for additional research to unravel the underlying mechanisms connecting psoriasis, endothelial dysfunction, and cardiovascular comorbidities. Ultimately, this research will contribute to the development of enhanced management strategies for psoriasis patients.

Cellular Mechanisms of Psoriasis Pathogenesis: A Systemic Review

Psoriasis is a common inflammatory skin disease characterized by abnormal proliferation of epidermal keratinocytes and massive infiltration of inflammatory cells. Many kinds of cells, including keratinocytes, T lymphocytes, dendritic cells, neutrophils, and macrophages, are reported to play critical roles in the pathogenesis and progression of psoriasis. However, to date, the role of each kind of cell in the pathogenesis and development of psoriasis has not been systematically reviewed. In addition, although antibodies developed targeting cytokines (e.g. IL-23, IL-17A, and TNF-α) released by these cells have shown promising results in the treatment of psoriasis patients, these targeted antibodies still do not cure psoriasis and only provide short-term relief of symptoms. Furthermore, long-term use of these antibodies has been reported to have adverse physical and psychological effects on psoriasis patients. Therefore, gaining a deeper understanding of the cellular and molecular pathogenesis of psoriasis and providing new thoughts on the development of psoriasis therapeutic drugs is of great necessity. In this review, we summarize the roles of various cells involved in psoriasis, aiming to provide new insights into the pathogenesis and development of psoriasis at the cellular level and hoping to provide new ideas for exploring new and effective psoriasis treatments.

Cux1+ proliferative basal cells promote epidermal hyperplasia in chronic dry skin disease identified by single-cell RNA transcriptomics

Pathological dry skin is a disturbing and intractable healthcare burden, characterized by epithelial hyperplasia and severe itch. Atopic dermatitis (AD) and psoriasis models with complications of dry skin have been studied using single-cell RNA sequencing (scRNA-seq). However, scRNA-seq analysis of the dry skin mouse model (acetone/ether/water (AEW)-treated model) is still lacking. Here, we used scRNA-seq and in situ hybridization to identify a novel proliferative basal cell (PBC) state that exclusively expresses transcription factor CUT-like homeobox 1 (Cux1). Further in vitro study demonstrated that Cux1 is vital for keratinocyte proliferation by regulating a series of cyclin-dependent kinases (CDKs) and cyclins. Clinically, Cux1+ PBCs were increased in patients with psoriasis, suggesting that Cux1+ PBCs play an important part in epidermal hyperplasia. This study presents a systematic knowledge of the transcriptomic changes in a chronic dry skin mouse model, as well as a potential therapeutic target against dry skin-related dermatoses.

Reactive Oxygen Species-Responsive Gel-Based Microneedle Patches for Prolonged and Intelligent Psoriasis Management

Psoriasis is an inflammatory skin disease. Microneedle (MN) patches can improve psoriasis treatment outcomes by increasing local drug content in the skin. As psoriasis frequently relapses, developing intelligent MN-based drug delivery systems with prolonged therapeutic drug levels and improved treatment efficiency is of great significance. Here, we designed detachable H₂O₂-responsive gel-based MN patches containing methotrexate (MTX) and epigallocatechin gallate (EGCG) by using EGCG as both cross-linkers for needle-composited materials and anti-inflammatory drugs. The gel-based MNs had dual-mode drug release kinetics, which quickly released MTX diffusively and sustainably released EGCG in an H₂O₂-responsive way. Compared with dissolving MNs, the gel-based MNs extended skin retention of EGCG, leading to prolonged reactive oxygen species (ROS) scavenging effects. The ROS-responsive MN patches that transdermally delivered antiproliferative and anti-inflammatory drugs improved treatment outcomes in both psoriasis-like and prophylactic psoriasis-like animal models.

Ferroptosis Activation Contributes to the Formation of Skin Lesions in Psoriasis Vulgaris

(1) Background: Ferroptosis is a newly coined form of programmed cell death marked by lethal accumulation of lipid peroxidation and ferrous iron overload. A few studies on the specific mechanism of ferroptosis in the genesis and development of psoriasis are available. (2) Methods: Levels of lipid reactive oxygen species (ROS) and ferrous iron were measured by flow cytometry. Ultrastructure analysis was performed by transmission electron microscopy. Imiquimod-induced psoriasis-like mice were treated with a ferroptosis inducer. The expressions of mRNA of genes were measured by qRT-PCR. HaCaT cells were used to explore the function of Cyb561d2. (3) Results: In this work, we observed that levels of lipid ROS and ferrous iron in the epidermis of psoriasis vulgaris (PV) patients were increased. The existence of ferroptosis activation in the epidermis of individuals with PV was confirmed by transmission electron microscope both in patients with PV and psoriasis-like mice models. Intradermal injection of the ferroptosis inducer RSL3 in psoriasis-like mice significantly promoted and aggravated the development of psoriasis-like dermatitis, and the level of serum transferrin was also increased in PV samples. Moreover, abnormal expression of some genes related to iron metabolism was also proved in the epidermis of PV cases, among which Cyb561d2 was shown to promote ferrous iron overload and lipid peroxidation accumulation in HaCaT cells. (4) Conclusions: In summary, our study suggested that ferroptosis activation owing to iron overload may be a novel mechanism underlying the formation of skin lesions in individuals with PV.

The Antimicrobial Peptide Cathelicidin Exerts Immunomodulatory Effects via Scavenger Receptors

An active form of cathelicidin antimicrobial peptide, LL-37, has immunomodulatory and stimulatory effects, though the specific pathways are not clear. The purpose of this study was to identify the cellular pathways by which LL-37 amplifies the inflammation induced by damage-associated molecular patterns (DAMPs). We performed DNA microarray, reverse transcription polymerase chain reaction, immunoblotting, and proximity ligation assays using cultured keratinocytes treated with LL-37 and/or the DAMP poly(I:C), a synthetic double-stranded RNA. In contrast to the combination of LL-37 and poly(I:C), LL-37 alone induced genes related to biological metabolic processes such as VEGFA and PTGS2 (COX-2). Inhibition of FPR2, a known receptor for cathelicidin, partially suppressed the induction of VEGFA and PTGS2. Importantly, VEGFA and PTGS2 induced by LL-37 alone were diminished by the knockdown of scavenger receptors including SCARB1 (SR-B1), OLR1 (SR-E1), and AGER (SR-J1). Moreover, LL-37 alone, as well as the combination of LL-37 and poly(I:C), showed proximity to the scavenger receptors, indicating that LL-37 acts via scavenger receptors and intermediates between them and poly(I:C). These results showed that the broad function of cathelicidin is generally dependent on scavenger receptors. Therefore, inhibitors of scavenger receptors or non-functional mock cathelicidin peptides may serve as new anti-inflammatory and immunosuppressive agents.

Pathogenesis, multi-omics research, and clinical treatment of psoriasis

Psoriasis is a common inflammatory skin disease involving interactions between keratinocytes and immune cells that significantly affects the quality of life. It is characterized by hyperproliferation and abnormal differentiation of keratinocytes and excessive infiltration of immune cells in the dermis and epidermis. The immune mechanism underlying this disease has been elucidated in the past few years. Research shows that psoriasis is regulated by the complex interactions among immune cells, such as keratinocytes, dendritic cells, T lymphocytes, neutrophils, macrophages, natural killer cells, mast cells, and other immune cells. An increasing number of signaling pathways have been found to be involved in the pathogenesis of psoriasis, which has prompted the search for new treatment targets. In the past decades, studies on the pathogenesis of psoriasis have focused on the development of targeted and highly effective therapies. In this review, we have discussed the relationship between various types of immune cells and psoriasis and summarized the major signaling pathways involved in the pathogenesis of psoriasis, including the PI3K/AKT/mTOR, JAK-STAT, JNK, and WNT pathways. In addition, we have discussed the results of the latest omics research on psoriasis and the epigenetics of the disease, which provide insights regarding its pathogenesis and therapeutic prospects; we have also summarized its treatment strategies and observations of clinical trials. In this paper, the various aspects of psoriasis are described in detail, and the limitations of the current treatment methods are emphasized. It is necessary to improve and innovate treatment methods from the molecular level of pathogenesis, and further provide new ideas for the treatment and research of psoriasis.

Pan-Cancer Analysis of BUB1B/hsa-miR-130a-3p Axis and Identification of Circulating hsa-miR-130a-3p as a Potential Biomarker for Cancer Risk Assessment

Based on the fact that very little was found in the literature on the question of potential molecules and mechanism for high risk of cancer in patients with psoriasis, this study was designed and performed based on bioinformatics analysis including WGCNA. The most striking result to emerge from the data is that BUB1B/hsa-miR-130a-3p axis, closely related to the development of psoriasis, also plays a remarkable role in multiple cancer development. The expression patterns of hsa-miR-130a-3p were found significantly changed in multiple tumors, which was also associated with prognosis. Additionally, hsa-miR-130a-3p was downregulated in lesion skin of psoriasis, but there was no difference in blood between psoriasis patients and normal controls. Circulating has-miR-130a-3p was found to have a higher level of blood in multiple tumor patients, suggesting that hsa-miR-130a-3p has the potential to be a blood biomarker for cancer risk assessment in patients with psoriasis.

Keratinocyte-derived S100A9 modulates neutrophil infiltration and affects psoriasis-like skin and joint disease

OBJECTIVES

S100A9, an alarmin that can form calprotectin (CP) heterodimers with S100A8, is mainly produced by keratinocytes and innate immune cells. The contribution of keratinocyte-derived S100A9 to psoriasis (Ps) and psoriatic arthritis (PsA) was evaluated using mouse models, and the potential usefulness of S100A9 as a Ps/PsA biomarker was assessed in patient samples.

METHODS

Conditional S100A9 mice were crossed with DKO* mice, an established psoriasis-like mouse model based on inducible epidermal deletion of c-Jun and JunB to achieve additional epidermal deletion of S100A9 (TKO* mice). Psoriatic skin and joint disease were evaluated in DKO* and TKO* by histology, microCT, RNA and proteomic analyses. Furthermore, S100A9 expression was analysed in skin, serum and synovial fluid samples of patients with Ps and PsA.

RESULTS

Compared with DKO* littermates, TKO* mice displayed enhanced skin disease severity, PsA incidence and neutrophil infiltration. Altered epidermal expression of selective pro-inflammatory genes and pathways, increased epidermal phosphorylation of STAT3 and higher circulating TNFα were observed in TKO* mice. In humans, synovial S100A9 levels were higher than the respective serum levels. Importantly, patients with PsA had significantly higher serum concentrations of S100A9, CP, VEGF, IL-6 and TNFα compared with patients with only Ps, but only S100A9 and CP could efficiently discriminate healthy individuals, patients with Ps and patients with PsA.

CONCLUSIONS

Keratinocyte-derived S100A9 plays a regulatory role in psoriatic skin and joint disease. In humans, S100A9/CP is a promising marker that could help in identifying patients with Ps at risk of developing PsA.

Human organ rejuvenation by VEGF-A: Lessons from the skin

Transplanting aged human skin onto young SCID/beige mice morphologically rejuvenates the xenotransplants. This is accompanied by angiogenesis, epidermal repigmentation, and substantial improvements in key aging-associated biomarkers, including ß-galactosidase, p16^ink4a, SIRT1, PGC1α, collagen 17A, and MMP1. Angiogenesis- and hypoxia-related pathways, namely, vascular endothelial growth factor A (VEGF-A) and HIF1A, are most up-regulated in rejuvenated human skin. This rejuvenation cascade, which can be prevented by VEGF-A-neutralizing antibodies, appears to be initiated by murine VEGF-A, which then up-regulates VEGF-A expression/secretion within aged human skin. While intradermally injected VEGF-loaded nanoparticles suffice to induce a molecular rejuvenation signature in aged human skin on old mice, VEGF-A treatment improves key aging parameters also in isolated, organ-cultured aged human skin, i.e., in the absence of functional skin vasculature, neural, or murine host inputs. This identifies VEGF-A as the first pharmacologically pliable master pathway for human organ rejuvenation in vivo and demonstrates the potential of our humanized mouse model for clinically relevant aging research.

Updated Perspectives on Keratinocytes and Psoriasis: Keratinocytes are More Than Innocent Bystanders

Psoriasis is a complex disease triggered by genetic, immunologic, and environmental stimuli. Many genes have been linked to psoriasis, like the psoriasis susceptibility genes, some of which are critical in keratinocyte biology and epidermal barrier function. Still, the exact pathogenesis of psoriasis is unknown. In the disease, the balance between the proliferative and differentiative processes of keratinocytes becomes altered. Multiple studies have highlighted the role of dysregulated immune cells in provoking the inflammatory responses seen in psoriasis. In addition to immune cells, accumulating evidence shows that keratinocytes are involved in psoriasis pathogenesis, as discussed in this review. Although certain immune cell-derived factors stimulate keratinocyte hyperproliferation, activated keratinocytes can also produce anti-microbial peptides, cytokines, and chemokines that can promote their proliferation, as well as recruit immune cells to help initiate and reinforce inflammatory feedback loops. Psoriatic keratinocytes also show intrinsic differences from normal keratinocytes even after removal from the in vivo inflammatory environment; thus, psoriatic keratinocytes have been found to exhibit abnormal calcium metabolism and possible epigenetic changes that contribute to psoriasis. The Koebner phenomenon, in which injury promotes the development of psoriatic lesions, also provides evidence for keratinocytes' contributions to disease pathogenesis. Furthermore, transgenic mouse studies have confirmed the importance of keratinocytes in the etiology of psoriasis. Finally, in addition to immune cells and keratinocytes, data in the literature support roles for other cell types, tissues, and systems in psoriasis development. These other contributors are all potential targets for therapies, suggesting the importance of a holistic approach when treating psoriasis.

Mechanism of Huoluo Xiaoling Dan in the Treatment of Psoriasis Based on Network Pharmacology and Molecular Docking

Objective

To explore the mechanism of the action of Huoluo Xiaoling Dan (HLXLD) in the treatment of psoriasis based on network pharmacology and molecular docking.

Methods

The main active components and targets of HLXLD were collected from CMSP, and the targets related to psoriasis were collected from GeneCards, OMIM, TTD, DisGeNET, and DrugBank. Drug disease target genes were obtained by Venny tools, drug-component-target networks were constructed and analyzed, and pathway enrichment analysis was performed. AutoDockTools is used to connect the core components and the target, and PyMOL software is used to visualize the results.

Results

126 active components (such as quercetin, luteolin, tanshinone IIA, dihydrotanshinlactone, and beta-sitosterol) and 238 targets of HLXLD were screened out. 1,293 targets of psoriasis were obtained, and 123 drug-disease targets were identified. Key targets included AKT1, TNF, IL6, TP53, VEGFA, JUN, CASP3, IL1B, STAT3, PTGS2, HIF1A, EGF, MYC, EGFR, MMP9, and PPARG. Enrichment analysis showed that 735 GO analysis and 85 KEGG pathways were mainly involved in biological processes such as response to the drug, inflammatory response, gene expression, and cell proliferation and apoptosis, as well as signal pathways such as cancer, TNF, HIF-1, and T cell receptor. Molecular docking showed that there was strong binding activity between the active ingredient and the target protein.

Conclusions

HLXLD could treat psoriasis through multicomponents, multitargets, and multipathways, which provides a new theoretical basis for further basic research and clinical application.

Physical exercise is associated with a reduction in plasma levels of fractalkine, TGF-β1, eotaxin-1 and IL-6 in younger adults with mobility disability

Mobility disability (MD) refers to substantial limitations in life activities that arise because of movement impairments. Although MD is most prevalent in older individuals, it can also affect younger adults. Increasing evidence suggests that inflammation can drive the development of MD and may need to be targeted for MD prevention. Physical exercise has anti-inflammatory properties and has been associated with MD prevention. However, no studies to date have examined whether exercise interventions affect the peripheral inflammatory status in younger adults with MD. To this end, we used blood samples from young and middle-aged adults with MD (N = 38; median age = 34 years) who participated in a 12-week intervention that included aerobic and resistance exercise training. A pre-post assessment of inflammatory biomarkers was conducted in plasma from two timepoints, i.e., before the exercise trial and at follow-up (3–7 days after the last exercise session). We successfully measured 15 inflammatory biomarkers and found that exercise was associated with a significant reduction in levels of soluble fractalkine, transforming growth factor beta 1 (TGF-β1), eotaxin-1 and interleukin (IL) 6 (corrected α = 0.004). We also found significant male-specific effects of exercise on (i) increasing IL-16 and (ii) decreasing vascular endothelial growth factor-A (VEGF-A). In line with our results, previous studies have also found that exercise can reduce levels of TGF-β1, eotaxin-1 and IL-6. However, our finding that exercise reduces plasma levels of fractalkine in younger adults with MD, as well as the sex-dependent findings, have not been previously reported and warrant replication in larger cohorts. Given the suggested role of inflammation in promoting MD development, our study provides additional support for the use of physical exercise as a treatment modality for MD.

Advances in the pathogenesis of psoriasis: from keratinocyte perspective

Psoriasis is a complex long-lasting inflammatory skin disease with high prevalence and associated comorbidity. It is characterized by epidermal hyperplasia and dermal infiltration of immune cells. Here, we review the role of keratinocytes in the pathogenesis of psoriasis, focusing on factors relevant to genetics, cytokines and receptors, metabolism, cell signaling, transcription factors, non-coding RNAs, antimicrobial peptides, and proteins with other different functions. The critical role of keratinocytes in initiating and maintaining the inflammatory state suggests the great significance of targeting keratinocytes for the treatment of psoriasis.

Angiogenesis in Chronic Inflammatory Skin Disorders

Angiogenesis, the growth of new blood vessels from preexisting vessels, is associated with inflammation in various pathological conditions. Well-known angiogenetic factors include vascular endothelial growth factor (VEGF), angiopoietins, platelet-derived growth factor, transforming growth factor-β, and basic fibroblast growth factor. Yes-associated protein 1 (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) have recently been added to an important angiogenic factor. Accumulating evidence indicates associations between angiogenesis and chronic inflammatory skin diseases. Angiogenesis is deeply involved in the pathogenesis of psoriasis. VEGF, angiopoietins, tumor necrosis factor-a, interleukin-8, and interleukin-17 are unregulated in psoriasis and induce angiogenesis. Angiogenesis may be involved in the pathogenesis of atopic dermatitis, and in particular, mast cells are a major source of VEGF expression. Angiogenesis is an essential process in rosacea, which is induced by LL-37 from a signal cascade by microorganisms, VEGF, and MMP-3 from mast cells. In addition, angiogenesis by increased VEGF has been reported in chronic urticaria and hidradenitis suppurativa. The finding that VEGF is expressed in inflammatory skin lesions indicates that inhibition of angiogenesis is a useful strategy for treatment of chronic, inflammatory skin disorders.

Alkyl-Terminated Gold Nanoparticles as a Self-Therapeutic Treatment for Psoriasis

We present a self-therapeutic nanoparticle for topical delivery to epidermal keratinocytes to prevent and treat psoriasis. Devoid of known chemical or biological antipsoriatic drugs, this sub-15 nm nanoparticle contains a 3 nm gold core and a shell of 1000 Da polyethylene glycol strands modified with 30% octadecyl chains. When it is applied to imiquimod-induced psoriasis mice without an excipient, the nanoparticle can cross the stratum corneum and preferentially enter keratinocytes. Applying the nanoparticles concurrently with imiquimod prevents psoriasis and downregulates genes that are enriched in the downstream of the interleukin-17 signaling pathway and linked to epidermis hyperproliferation and inflammation. Applying the nanoparticles after psoriasis is established treats the psoriatic skin as effectively as standard steroid and vitamin D analog-based therapy but without hair loss and skin wrinkling. The nanoparticles do not accumulate in major organs or induce long-term toxicity. Our nanoparticle offers a simple, safe, and effective alternative for treating psoriasis.

Current Concepts of Psoriasis Immunopathogenesis

Psoriasis is a recurrent, chronic, immune-mediated, systemic inflammatory disease of the skin, joints, and other organic systems. After atopic dermatitis, chronic stationary psoriasis is the most common inflammatory skin disease, affecting an average of 2-4% of the world's population. The disease carries a significant burden due to its numerous comorbidities and the major impact on patients' social and emotional aspects of life. According to current knowledge, psoriasis is a multifactorial disease that occurs in genetically predisposed individuals under various environmental factors, which trigger an immune response disorder with a series of complex inflammatory cascades. The disease is initiated and maintained by mutual interaction of the innate and adaptive immune cells, primarily dendritic cells, T lymphocytes, and keratinocytes, whose leading role alternates at different stages of the disease, consisting mainly in the IL-23/Th17 pathway. Inflammatory events result in consequent epidermal and dermal changes and evolution of the characteristic psoriatic phenotype, respectively. This paper aims to present a comprehensive overview of current knowledge on psoriasis genetic and environmental etiological factors, immunopathogenesis, and the leading cellular and cytokine participants in the inflammatory pathways of this disease.

Regulatory T Cells in Angiogenesis

Regulatory T cells (Tregs) are crucial mediators of immune homeostasis. They regulate immune response by suppressing inflammation and promoting self-tolerance. In addition to their immunoregulatory role, a growing body of evidence highlights the dynamic role of Tregs in angiogenesis, the process of forming new blood vessels. Although angiogenesis is critically important for normal tissue regeneration, it is also a hallmark of pathological processes, including malignancy and chronic inflammation. Interestingly, the role of Tregs in angiogenesis has been shown to be highly tissue- and context-specific and as a result can yield either pro- or antiangiogenic effects. For these reasons, there is considerable interest in determining the molecular underpinnings of Treg-mediated modulation of angiogenesis in different disease states. The present review summarizes the role of Tregs in angiogenesis and mechanisms by which Tregs regulate angiogenesis and discusses how these mechanisms differ in homeostatic and pathological settings.

The calcium-activated chloride channel-associated protein rCLCA2 is expressed throughout rat epidermis, facilitates apoptosis and is downmodulated by UVB

The rodent chloride channel regulatory proteins mCLCA2 and its porcine and human homologues pCLCA2 and hCLCA2 are expressed in keratinocytes but their localization and significance in the epidermis have remained elusive. hCLCA2 regulates cancer cell migration, invasion and apoptosis, and its loss predicts poor prognosis in many tumors. Here, we studied the influences of epidermal maturation and UV-irradiation (UVR) on rCLCA2 (previous rCLCA5) expression in cultured rat epidermal keratinocytes (REK) and correlated the results with mCLCA2 expression in mouse skin in vivo. Furthermore, we explored the influence of rCLCA2 silencing on UVR-induced apoptosis. rClca2 mRNA was strongly expressed in REK cells, and its level in organotypic cultures remained unchanged during the epidermal maturation process from a single cell layer to fully differentiated, stratified cultures. Immunostaining confirmed its uniform localization throughout the epidermal layers in REK cultures and in rat skin. A single dose of UVR modestly downregulated rClca2 expression in organotypic REK cultures. The immunohistochemical staining showed that CLCA2 localized in basal and spinous layers also in mouse skin, and repeated UVR induced its partial loss. Interestingly, silencing of rCLCA2 reduced the number of apoptotic cells induced by UVR, suggesting that by facilitating apoptosis, CLCA2 may protect keratinocytes against the risk of malignancy posed by UVB-induced corrupt DNA.

Intrinsic Abnormalities of Keratinocytes Initiate Skin Inflammation through the IL-23/T17 Axis in a MALT1-Dependent Manner

Increasing evidence has supported the crucial role of CARD14 in the pathogenesis of psoriasis, whereas the precise cellular signaling involved in skin physiopathology remains poorly understood. In this article, we show that neither genetic ablation of Il17a nor elimination of T cells was sufficient to restrain the skin inflammation in a CARD14-E138A-mutation-induced psoriasis-like mouse model, whereas depletion of Il23, which extremely blocked the IL-23/T17 axis, was more effective. Targeting CBM complex by conditional deletion of MALT1 or BCL10 in keratinocytes abrogated both the cutaneous and systemic inflammation of heterozygous Card14 ^E138A/+ mice. Selective inactivation of keratinocyte-specific MALT1 proteolytic activity strongly ameliorated the Card14 ^E138A/+- and Card14 ^ΔQ136/+-induced skin disease, which was reproduced by using the imiquimod-induced mouse model. Together, our results suggest a sequence of events under CARD14-mutation-induced psoriasis condition that keratinocyte-intrinsic activation of CBM complex initiates the skin inflammation depending on the IL-23/T17 axis. Targeting keratinocytes by inactivation of MALT1 paracaspase activity might be a promising therapeutic target for early psoriasis treatment.

Vascular endothelial growth factor-A as a promising therapeutic target for the management of psoriasis

Vascular endothelial growth factor-A (VEGF-A), the main angiogenic mediator, plays a critical role in the pathogenesis of several inflammatory immune-mediated diseases, including psoriasis. Even though anti-angiogenic therapies, such as VEGF inhibitors, are licensed for the treatment of various cancers and eye disease, VEGF-targeting interventions are not part of current psoriasis therapy. In this viewpoint essay, we argue that the existing preclinical research evidence on the role of VEGF-A in the pathogenesis of psoriasis as well as clinical observations in patients who have experienced psoriasis remission during oncological anti-VEGF-A therapy strongly suggests to systematically explore angiogenesis targeting also in the management of psoriasis. We also point out that some psoriasis therapies decrease circulating levels of VEGF-A and normalise the psoriasis-associated vascular pathology in the papillary dermis of plaques of psoriasis and that a subset of patients with constitutionally high levels of VEGF-A may benefit most from the anti-angiogenic therapy we advocate here. Given that novel, well-targeted personalised medicine therapies for the development of psoriasis need to be developed, we explore the hypothesis that VEGF-A and signalling through its receptors constitute a promising target for therapeutic intervention in the future management of psoriasis.

Keratinocyte: A trigger or an executor of psoriasis?

Psoriasis is a common chronic inflammatory skin disease characterized by abnormal proliferation/differentiation of keratinocytes and excessive immune cell infiltration in the dermis and epidermis. Over the past 2 decades, immune cells have been considered as the main driver of psoriasis because the neutralizing antibodies targeting the IL-23/IL-17 axis that regulates cross-talk between dendritic cells and T cells achieve tremendous success in the treatment of psoriasis. However, whether keratinocyte would be a driver of psoriasis or just an executor in response to immune cells is still under debate. In this review, we focus on the recent advances in the identification of keratinocyte as a trigger of psoriasis, summarize on the role of keratinocytes in self-perpetuating loop to maintain inflammation in psoriasis, and then discuss the possible roles of keratinocytes in the relapse of psoriasis.