Neutrophils impaired by anti-galectin-3 antibodies elicit inflammation of endothelial cells to aggregate the development of lupus cutaneous vasculitis.

OBJECTIVES: To investigate whether the interplay of anti-galectin-3 antibodies (anti-Gal3 Abs) with neutrophils contributes to the development of lupus cutaneous vasculitis. METHODS: Enzyme-linked immunosorbent assay was used to determine the serum level of anti-Gal3 Abs in lupus patients. Flow cytometry, quantitative PCR and western blot were performed to investigate the expression of cell surface receptors, proinflammatory cytokines and signalling molecules in neutrophils stimulated by serum from lupus patients or healthy controls (HCs) or anti-Gal3 Ab, respectively. Immunofluorescence was performed to visualise the formation of neutrophil extracellular traps (NETs). Human umbilical vein endothelial cells were co-cultured with the supernatants from neutrophils stimulated by anti-Gal3 Ab, and cytokine production was measured at mRNA and protein levels. Immunohistochemistry was adopted to reveal the distribution of Gal3, cytokines and myeloperoxidase within lupus skin lesions. REULTS: Serum levels of anti-Gal3 Abs were negatively correlated with peripheral counts of neutrophils. Anti-Gal3 Abs positive sera from SLE patients accelerated neutrophil death, altered cell phenotype and promoted formation of NETs with the involvement of p38 MAPK pathway. Supernatants collected from neutrophils co-cultured with anti-Gal3 Ab provoked endothelial cells to produce cytokines such as IL-1, ICAM-1, SELE and particularly IL-6. Consistently, IL-6 was higher in SLE patients with anti-Gal3 Ab positive sera and enriched in the area of vascular inflammation together with enhanced expression of Gal3 protein and infiltration of neutrophils. CONCLUSIONS: Overall, these findings suggested that neutrophils were crucial mediators in anti-Gal3 Ab induced lupus cutaneous vasculitis.

Artesunate alleviates psoriasis-like dermatitis by reducing interleukin-23 expression in tumor necrosis factor-alpha-induced HaCaT cells.

Artesunate (ART), an antimalarial drug with a multifunctional immunomodulatory effect, reduces psoriasis disease. ART can alleviate psoriasis-like dermatitis in mice but has no effect on proinflammatory cytokines in the blood. Thus, we hypothesized that the skin might be the target tissue of ART during the treatment of psoriasis. The interleukin (IL)-23/IL-17 axis has a key role in the pathogenesis of psoriasis. However, whether and how ART manipulates the IL-23 signal during psoriasis is unknown. This study found that IL-23 is highly expressed in the epidermis of psoriasis lesions and positively correlated with histological neutrophil infiltration and clinical psoriasis area and severity index (PASI) scores. Furthermore, ART inhibits the migration and cell cycle, as well as tumor necrosis factor-alpha (TNF-α)-induced IL-23 expression in HaCaT cells in a dose-dependent manner, probably through interference with the nuclear factor kappa B (NF-κB) signalling pathway. Animal experiments in imiquimod (IMQ)-induced psoriasis-like mice model also suggested that ART dose-dependently reduces IL-23 in the epidermis and ameliorates neutrophil infiltration. These findings thus provide further molecular evidence supporting ART as a promising drug for psoriasis in clinic.

Impact of Gut Bacterial Metabolites on Psoriasis and Psoriatic Arthritis: Current Status and Future Perspectives.

There is growing evidence that supports a role of gut dysbiosis in the pathogenesis of psoriasis (Pso). Thus, probiotic supplementation and fecal microbiota transplantation may serve as promising preventive and therapeutic strategies for patients with Pso. One of the basic mechanisms through which the gut microbiota interacts with the host is through bacteria-derived metabolites, usually intermediate or end products produced by microbial metabolism. In this study, we provide an up-to-date review of the most recent literature on microbial-derived metabolites and highlight their roles in the immune system, with a special focus on Pso and one of its most common comorbidities, psoriatic arthritis.

TNF-α promotes CXCL-1/8 production in keratinocytes by downregulating galectin-3 through NF-κB and hsa-miR-27a-3p pathway to contribute psoriasis development.

OBJECTIVE: Treatment with TNF-α inhibitors improve psoriasis with minimize/minor neutrophils infiltration and CXCL-1/8 expression in psoriatic lesions. However, the fine mechanism of TNF-α initiating psoriatic inflammation by tuning keratinocytes is unclear. Our previous research identified the deficiency of intracellular galectin-3 was sufficient to promote psoriasis inflammation characterized by neutrophil accumulation. This study aims to investigate whether TNF-α participated in psoriasis development through dysregulating galectin-3 expression. METHODS: mRNA levels were assessed through quantitative real-time PCR. Flow cytometry was used to detect cell cycle/apoptosis. Western blot was used to evaluate the activation of the NF-κB signaling pathway. HE staining and immunochemistry were used to detect epidermal thickness and MPO expression, respectively. Specific small interfering RNA (siRNA) was used to knock down hsa-miR-27a-3p while plasmids transfection was used to overexpress galectin-3. Further, the multiMiR R package was utilized to predict microRNA-target interaction. RESULTS AND DISCUSSION: We found that TNF-α stimulation altered cell proliferation and differentiation and promoted the production of psoriasis-related inflammatory mediators along with the inhibition of galectin-3 expression in keratinocytes. Supplement of galectin-3 could counteract the rise of CXCL-1/8 but not the other phenotypes of keratinocytes induced by TNF-α. Mechanistically, inhibition of the NF-κB signaling pathway could counteract the decrease of galectin-3 and the increase of hsa-miR-27a-3p expression whereas silence of hsa-miR-27a-3p could counteract the decrease of galectin-3 expression induced by TNF-α treatment in keratinocytes. Intradermal injection of murine anti-CXCL-2 antibody greatly alleviated imiquimod-induced psoriasis-like dermatitis. CONCLUSION: TNF-α initiates psoriatic inflammation by increasing CXCL-1/8 in keratinocytes mediated by the axis of NF-κB-hsa-miR-27a-3p-galectin-3 pathway.

CD19+CD24highCD27+ B cell and interleukin 35 as potential biomarkers of disease activity in systemic lupus erythematosus patients.

BACKGROUND: Systemic lupus erythematosus (SLE) is a systemic autoimmune disease that associates with aberrant activation of B lymphocytes and excessive autoantibodies. Interleukin 10 (IL-10)/interleukin 35 (IL-35) and IL-10/IL-35-producing regulatory B cells have been demonstrated to possess immunosuppressive functions during systemic lupus erythematosus. Here, we detected the proportion of CD19+CD24highCD27+ B cells as well as IL-10 and IL-35 levels in peripheral blood of SLE patients and healthy individuals, and investigated their relations with clinical features of SLE. METHODS: 41 SLE patients and 25 healthy controls were recruited. The patients were divided into groups based on SLEDAI score, anti-dsDNA antibody, rash, nephritis and hematological disorder. Flow cytometry was used to detect the proportion of CD24hiCD27+ B cells. ELISA was used to detect serum levels of IL-10 and IL-35. RESULTS: Our results showed that the CD19+CD24highCD27+ B population was decreased in active SLE patients, and anti-correlated with the disease activity. Of note, we found significant increase of IL-10 and decrease of IL-35 in SLE patients with disease activity score > 4, lupus nephritis or hematological disorders compared to those without related clinical features. CONCLUSIONS: Reduced CD19+CD24highCD27+ B cells expression may be involved in the pathogenesis of SLE. Moreover, we supposed that IL-35 instead of IL-10 played a crucial role in immune regulation during SLE disease.

Gain-of-function of TRPM4 predisposes mice to psoriasiform dermatitis.

Transient receptor potential melastatin 4 (TRPM4) is a Ca2+-activated, monovalent cation channel that is expressed in a wide range of cells. We previously reported two gain-of-function (GoF) mutations of TRPM4 as the cause of progressive symmetric erythrokeratodermia (PSEK), which shares similar clinical and histopathological features with psoriasis. Using CRISPR/Cas9 technology, we generated TRPM4I1029M mice that have the equivalent mutation to one of the two genetic mutations found in human PSEK (equivalent to human TRPM4I1033M). Using this mutant mice, we examined the effects of TRPM4 GoF at the cellular and phenotypic levels to elucidate the pathological mechanisms underlying PSEK. In the absence of experimental stimulation, TRPM4I1029M mice did not show a phenotype. When treated with imiquimod (IMQ), however, TRPM4I1029M mice were predisposed to more severe psoriasiform dermatitis (PsD) than wild-type (WT), which was characterized by greater accumulation of CCR6-expressing γδ T cells and higher mRNA levels of Il17a. In TRPM4I1029M mice, dendritic cells showed enhanced migration and keratinocytes exhibited increased proliferation. Moreover, a TRPM4 inhibitor, glibenclamide, ameliorated PsD in WT and TRPM4I1029M mice. Our results indicate elevated TRPM4 activities boosted susceptibility to cutaneous stimuli, likely through elevation of membrane potential and alteration of downstream cellular signaling, resulting in enhanced inflammation. Our results further suggest a possible therapeutic application of TRPM4 inhibitors in psoriasis.

Profiling Serum Cytokines and Anticytokine Antibodies in Psoriasis Patients.

Cytokines like IL-17A have been consistently found to be elevated in psoriatic lesional skin, and therapeutic antibodies to IL-17 have demonstrated efficacy in treating psoriatic skin and joint disease. However, results about the circulating cytokines in psoriasis patients remained controversial. Anticytokine autoantibodies (ACAAs) were detected in various autoimmune diseases but remained largely unknown in psoriasis. We aimed to investigate the serum levels of cytokines and ACAAs in psoriasis patients. The study included 44 biologics-naive psoriasis patients and 40 healthy controls. Serum cytokines and the corresponding autoantibodies were measured by multiplex bead-based technology. The bioactivity of serum IL-17A was determined by IL-8 production in primary keratinocytes. Herein, we found serum levels of IL-12B (median: 6.16 vs. 9.03, p = 0.0194) and Th17 cytokines (IL-17A: median: 0.32 vs. 1.05, p = 0.0026; IL-22: median: 4.41 vs. 4.41, p = 0.0120) were increased in psoriasis patients. More interestingly, bioactive IL-17A was identified in a proportion of patients and positively correlated with disease severity. A few of cytokines were closely associated with each other and formed into a distinct panel in psoriasis. Of 13 anticytokine antibodies, anti-IL-22 was moderately lower (median: 262.8 vs.190.5, p = 0.0418), and anti-IL-15 was slightly higher (median: 25.5 vs. 30.5, p = 0.0069) in psoriasis than controls. None of ACAAs was related to disease severity. Consequently, the ratios of antibodies to cytokines varied with the pattern of cytokines. In summary, our finding suggested that the levels of circulating bioactive IL-17A were associated with disease activity in psoriasis patients. In contrast, the titers of ACAAs were not significantly altered nor correlated with disease severity. However, the functionality of ACAAs remains to be further demonstrated in vitro in future studies.

Anti-galectin-3 antibodies induce skin vascular inflammation via promoting local production of IL-1ß in systemic lupus erythematosus.

Vascular inflammation could occur in all organs and tissues in patients with systematic lupus erythematosus (SLE), of which skin is the most frequent one. Our previous research identified anti-galectin-3 (Gal3) antibodies (Abs) as an important mediator of lupus cutaneous vasculopathy. Herein, we showed that anti-Gal3 Abs dysregulated the function of vascular endothelial cells with higher transcript levels of IL-1ß and increased expression of mature IL-1ß. The enhanced production of IL-1ß secreted by endothelial cells was dependent on NLRP3 inflammasome. Intradermal injection of anti-Gal3 Abs in mice induced local inflammation with perivascular infiltration of T cells and neutrophils, which was inhibited by IL-1ß blockade. Induction of anti-Gal3 Abs in circulation by immunization of Gal3 antigen not only led to histopathologic changes in the skin, including focal keratinocytes vacuolization and thickening of blood vessels, but also a systemic autoimmune phenotype that involves autoantibody production and kidney damage. Intriguingly, local overexpression of IL-1ß was primarily associated with skin lesions but not with other internal organs in mice. Finally, we showed that the serum levels of IL-1ß were comparable between SLE patients and healthy donors. Whilst the expression of IL-1ß was enriched in local area with perivascular inflammation in lupus skin lesion compared to healthy normal skin. The results strongly suggest that IL-1ß plays an important role in mediating anti-Gal3 Ab-induced skin vascular inflammation and raised the prospect for using IL-1ß blocking therapies to treat lupus cutaneous damage.

Nuclear receptor RORγ inverse agonists/antagonists display tissue- and gene-context selectivity through distinct activities in altering chromatin accessibility and master regulator SREBP2 occupancy.

The nuclear receptor RORγ is a major driver of autoimmune diseases and certain types of cancer due to its aberrant function in T helper 17 (Th17) cell differentiation and tumor cholesterol metabolism, respectively. Compound screening using the classic receptor-coactivator interaction perturbation scheme led to identification of many small-molecule modulators of RORγ(t). We report here that inverse agonists/antagonists of RORγ such as VTP-43742 derivative VTP-23 and TAK828F, which can potently inhibit the inflammatory gene program in Th17 cells, unexpectedly lack high potency in inhibiting the growth of TNBC tumor cells. In contrast, antagonists such as XY018 and GSK805 that strongly suppress tumor cell growth and survival display only modest activities in reducing Th17-related cytokine expression. Unexpectedly, we found that VTP-23 significantly induces the cholesterol biosynthesis program in TNBC cells. Our further mechanistic analyses revealed that VTP-23 enhances the local chromatin accessibility, H3K27ac mark and the cholesterol master regulator SREBP2 recruitment at the RORγ binding sites, whereas XY018 exerts the opposite activities. Yet, they display similar inhibitory effects on circadian rhythm program. Similar distinctions and contrasting activities between TAK828F and SR2211 in their effects on local chromatin structure at Il17 genes were also observed. Together, our study shows for the first-time that structurally distinct RORγ antagonists possess different or even contrasting activities in tissue/cell-specific manner. Our findings also highlight that the activities at natural chromatin are key determinants of RORγ modulators' tissue selectivity.

Etanercept treatment of Stevens-Johnson syndrome and toxic epidermal necrolysis.

BACKGROUND: Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a severe cutaneous adverse reaction to drugs with considerable morbidity and mortality. Immunomodulators for SJS/TEN including systemic corticosteroids and intravenous immunoglobulin (IVIG) have been widely used in clinical practice. Emerging evidence suggested the therapeutic effects of tumor necrosis factor-α antagonists on SJS/TEN. OBJECTIVE: To compare the efficacy and safety of IVIG and systemic steroids in conjunction with or without etanercept, a tumor necrosis factor-α inhibitor, for patients with SJS/TEN. METHODS: We undertook a retrospective review of 41 patients with SJS/TEN admitted to our institution from 2015 to February 2021. A total of 25 patients with integrated data were involved in this study, of which 14 patients were treated with IVIG and corticosteroids and 11 were in addition given etanercept. The clinical characteristics, duration of hospitalization, exposure time to high-dose steroids, and the total amount of systemic steroids were analyzed. RESULTS: In comparison to conventional therapy, conjunction with etanercept reduced the duration of hospitalization (13.5 vs 19.0 days; P = .01), the exposure time of high-dose steroids (7.1 vs 14.9 days; P = .01), and the overall amount of systemic steroid (925 mg vs 1412.5 mg; P = .03) in patients with SJS/TEN. No pronounced adverse effects were observed within 6 months of follow-up after the treatment. CONCLUSION: The add-in of etanercept at the time of initiating conventional therapy could be a superior option to accelerate disease recovery and reduce the high dose and total amount of systemic steroids without pronounced adverse events in patients with SJS/TEN.

Enhanced Migratory Ability of Neutrophils Toward Epidermis Contributes to the Development of Psoriasis via Crosstalk With Keratinocytes by Releasing IL-17A.

Microabscess of neutrophils in epidermis is one of the histological hallmarks of psoriasis. The axis of neutrophil-keratinocyte has been thought to play a critical role in the pathogenesis of psoriasis. However, the features and mechanism of interaction between the two cell types remain largely unknown. Herein, we found that blood neutrophils were increased in psoriasis patients, positively correlated with disease severity and highly expressed CD66b, but not CD11b and CD62L compared to healthy controls. Keratinocytes expressed high levels of psoriasis-related inflammatory mediators by direct and indirect interaction with neutrophils isolated from psoriasis patients and healthy controls. The capacity of neutrophils in provoking keratinocytes inflammatory response was comparable between the two groups and is dependent on IL-17A produced by itself. Neutrophils isolated from psoriasis patients displayed more transcriptome changes related to integrin and increased migration capacity toward keratinocytes with high CD11b expression on cell surface. Of interest, neutrophils were more susceptible to keratinocyte stimulation than to fibroblasts and human umbilical vein endothelial cells (HUVECs) in terms of CD11b expression and the production of ROS and NETs. In conclusion, neutrophils from psoriasis patients gain a strong capacity of IL-17A production and integrins expression that possibly facilitates their abilities to promote production of psoriasis-related inflammatory mediators and migration, a phenomenon likely induced by their interaction with keratinocytes but not with fibroblasts. These findings provide a proof-of-concept that development of new drugs targeting migration of neutrophils could be a more specific and safe solution to treat psoriasis.

New Insights into Artesunate as a Pleiotropic Regulator of Innate and Adaptive Immune Cells.

Artesunate, one of the derivatives of artemisinin ("qinghaosu" in Chinese), is known as an antimalarial drug with high efficiency and low toxicity. Of interest, emerging evidences suggest that artesunate also possesses an immunomodulatory effect during innate and adaptive immune responses in cell types and context-dependent manner. Although it shows promising application in many diseases, such as inflammatory diseases, hypersensitivity, autoimmune diseases, and cancers, little is known about underlying molecular. In this review, we summarize recent advances of how artesunate regulates innate and adaptive immune cells. In addition, its potential application in immune-related diseases is also highlighted.

Bile Acids Improve Psoriasiform Dermatitis through Inhibition of IL-17A Expression and CCL20-CCR6-Mediated Trafficking of T Cells.

Bile acids (BAs), produced in the liver and further transformed in the gut, are cholesterol-derived molecules involved in essential physiological processes. Recent studies suggest that BAs regulate T helper 17 cell function, but the underlying mechanism of this action and their therapeutic value in disease models remains unclear. Using an IL-23 minicircle DNA-based murine model of psoriasiform dermatitis, we showed that oral administration of secondary BAs, including lithocholic acid (LCA), deoxycholic acid, and 3-oxoLCA, significantly improved psoriasiform dermatitis without inducing apparent hepatotoxicity. Of the BAs tested, LCA possessed the greatest potency in treating psoriasiform dermatitis. Intravenous administration of LCA at a much lower dosage (compared with oral treatment) showed a comparable antipsoriatic effect and markedly suppressed the IL-17A response. Ex vivo experiments revealed that LCA reduced IL-17A production in IL-23-stimulated murine T cells in the absence of BA receptors TGR5 or FXR. Strikingly, BAs inhibited CCL20 expression in keratinocytes, which led to reduced migration of CCR6-expressing Jurkat cells cultured in the conditioned medium of stimulated keratinocytes. Thus, BAs improve psoriasiform dermatitis with minimal toxicity via direct inhibition of IL-17A production and blockade of CCL20-mediated trafficking, supporting the potential use of BAs in psoriasis.

ULK1 Inhibition as a Targeted Therapeutic Strategy for Psoriasis by Regulating Keratinocytes and Their Crosstalk With Neutrophils.

Psoriasis is a common inflammatory skin disease resulting from an interplay of keratinocytes and immune cells. Previous studies have identified an essential role of autophagy in the maintenance of epidermal homeostasis including proliferation and differentiation. However, much less is known about the role of autophagy-related proteins in the cutaneous immune response. Herein, we showed that ULK1, the key autophagic initiator, and its phosphorylation at Ser556 were distinctively decreased in the epidermis from lesional skin of psoriasis patients. Topical application of SBI0206965, a selective ULK1 inhibitor, significantly attenuated epidermal hyperplasia, infiltration of neutrophils, and transcripts of the psoriasis-related markers in imiquimod (IMQ)-induced psoriasiform dermatitis (PsD). In vitro, ULK1 impairment by siRNA and SBI0206965 arrested cell proliferation and promoted apoptosis of keratinocytes but had a marginal effect on the expression of proinflammatory mediators under steady status. Surprisingly, SBI0206965 blocked the production of chemokines and cytokines in keratinocytes stimulated by neutrophils. Of interest, the pro-apoptotic and anti-inflammatory effects of ULK1 inhibition cannot be fully replicated by autophagic inhibitors. Our findings suggest a self-regulatory process by downregulating ULK1 to maintain the immune homeostasis of psoriatic skin via regulating keratinocytes and their crosstalk with neutrophils, possibly through both autophagy-dependent and independent mechanisms. ULK1 might be a potential target for preventing or treating psoriasis.

GRAPPA 2019 Research Recipient Awards Report.

A summary of the research conducted by the recipients of the 2019 Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) Research Awards is presented. Dr. Alla Ishchenko's project was "Role of Metabolomics in Diagnosis, Disease Severity, and Progression in Psoriasis and Psoriatic Arthritis: A 2-year Prospective Pilot Study" and Dr. Zhenrui Shi's project was "Preclinical Analysis of CCR6 and CCL20 in Mouse and Human Joints, Respectively, as Targets of Therapeutic Intervention in Psoriatic Arthritis."

Targeting the CCR6/CCL20 Axis in Entheseal and Cutaneous Inflammation.

OBJECTIVE: To assess the involvement of the CCR6/CCL20 axis in psoriatic arthritis (PsA) and psoriasis (PsO) and to evaluate its potential as a therapeutic target. METHODS: First, we quantified CCL20 levels in peripheral blood and synovial fluid from PsA patients and examined the presence of CCR6+ cells in synovial and tendon tissue. Utilizing an interleukin-23 minicircle DNA (IL-23 MC) mouse model exhibiting key features of both PsO and PsA, we investigated CCR6 and CCL20 expression as well as the preventive and therapeutic effect of CCL20 blockade. Healthy tendon stromal cells were stimulated in vitro with IL-1ß to assess the production of CCL20 by quantitative polymerase chain reaction and enzyme-linked immunosorbent assay. The effect of conditioned media from stimulated tenocytes in inducing T cell migration was interrogated using a Transwell system. RESULTS: We observed an up-regulation of both CCR6 and CCL20 in the enthesis of IL-23 MC-treated mice, which was confirmed in human biopsy specimens. Specific targeting of the CCR6/CCL20 axis with a CCL20 locked dimer (CCL20LD) blocked entheseal inflammation, leading to profound reductions in clinical and proinflammatory markers in the joints and skin of IL-23 MC-treated mice. The stromal compartment in the tendon was the main source of CCL20 in this model and, accordingly, in vitro activated human tendon cells were able to produce this chemokine and to induce CCR6+ T cell migration, the latter of which could be blocked by CCL20LD. CONCLUSION: Our study highlights the pathogenic role of the CCR6/CCL20 axis in enthesitis and introduces the prospect of a novel therapeutic approach for treating patients with PsO and PsA.