Imiquimod-induced psoriasis-like skin inflammation in mice is mediated via the IL-23/IL-17 axis

Keratinocyte and myeloid MCPIP1 have distinct roles in maintaining skin homeostasis

The skin is a complex organ, and the intricate network between keratinocytes and immune cells is critical for ensuring skin function. Monocyte chemotactic protein-1-induced protein 1 (MCPIP1) is a ribonuclease that functions as a key negative modulator of inflammation. We previously reported that conditional deletion of MCPIP1 in keratinocytes (Mcpip1EKO) impairs skin integrity in adult mice. A similar phenotype was observed following the depletion of MCPIP1 in the myeloid compartment (Mcpip1MKO). The aim of this study was to develop a keratinocyte and myeloid double-MCPIP1 knockout mouse model to clarify the specific roles of myeloid and epidermal MCPIP1 in skin biology. Histological analyses indicated that the skin morphology changed after depletion of MCPIP1 in cells of myeloid origin as well as in keratinocytes. The thicknesses of the epidermal and subcutaneous fat layers increased in the mice with a loss of epidermal MCPIP1, whereas the loss of myeloid MCPIP1 had the opposite effect. In addition, both types of mice showed opposite responses to stimulation with 12-O-tetradecanoylphorbol-13-acetate. Transcriptomic profiling of whole-skin lysates revealed some common target transcripts in all the knockout mice. Further analyses revealed that distinct pathways are modulated following the loss of epidermal or myeloid MCPIP1. The skin morphology and inflammatory phenotype of keratinocyte and myeloid double-MCPIP1 knockout mice resembled those of mice with only keratinocyte-specific knockout of MCPIP1. Overall, myeloid and epidermal MCPIP1 play important but distinct roles in the modulation of skin-related processes.

Tetrastigma hemsleyanum polysaccharides alleviate imiquimod-induced psoriasis-like skin lesions in mice by modulating the JAK/STAT3 signaling pathway

BACKGROUND

The pathogenesis of psoriasis involves the interaction between keratinocytes and immune cells, leading to immune imbalance. While most current clinical treatment regimens offer rapid symptom relief, they often come with significant side effects. Tetrastigma hemsleyanum polysaccharides (THP), which are naturally nontoxic, possess remarkable immunomodulatory and anti-inflammatory properties.

METHODS

In this study, we utilized an imiquimod (IMQ)-induced psoriasis mouse model and a LPS/IL-6-stimulated HaCaT model. The potential and mechanism of action of THP in psoriasis treatment were assessed through methods including Psoriasis Area Severity Index (PASI) scoring, histopathology, flow cytometry, immunoblotting, and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Percutaneous administration of THP significantly alleviated symptoms and manifestations in IMQ-induced psoriatic mice, including improvements in psoriatic skin appearance (erythema, folds, scales), histopathological changes, decreased PASI scores, and spleen index. Additionally, THP suppressed abnormal proliferation of Th17 cells and excessive proliferation and inflammation of keratinocytes. Furthermore, THP exhibited the ability to regulate the JAK/STAT3 signaling pathway.

CONCLUSION

Findings from in vivo and in vitro studies suggest that THP can inhibit abnormal cell proliferation and excessive inflammation in lesional skin, balance Th17 immune cells, and disrupt the interaction between keratinocytes and Th17 cells. This mechanism of action may involve the modulation of the JAK/STAT3 signaling pathway, offering potential implications for psoriasis treatment.

Pilot study of the role of ferroptosis in abnormal biological behaviour of keratinocytes in psoriasis vulgaris

BACKGROUND

Abnormal biological behaviour of keratinocytes (KCs) is a critical pathophysiological manifestation of psoriasis. Ferroptosis is programmed cell death induced by the accumulation of lipid reactive oxygen species (ROS) in the presence of increased intracellular iron ions or inhibition of GPX4.

OBJECTIVES

The purpose of this study was to investigate the effects of ferroptosis on the biological behaviour of Keratinocytes (KCs) in psoriasis vulgaris and its possible regulatory mechanisms in clinical samples, cells, and mouse models.

METHODS

We first examined the differences in the expression of GPX4 and 4-HNE between psoriasis and normal human lesions. And detected KRT6, FLG, and inflammatory cytokines after inducing ferroptosis in animal and cell models by RT-qPCR, Western blot, immunohistochemistry, and flow cytometry.

RESULTS

We found that GPX4 was decreased and that the oxidation product 4-hydroxy-2-nonenal (HNE) was increased in the skin lesions of patients with psoriasis vulgaris. The expression level of GPX4 correlates with the severity of skin lesions. Moreover, inducing ferroptosis promoted the expression of FLG and reduced the expression of KRT6 and inflammatory cytokines in vitro, and alleviated the phenotype of skin lesions in vivo.

LIMITATIONS

Our study has limitations, notably small sample size. Larger clinical trials are necessary to investigate the association between ferroptosis and disease progression further. More research is necessary to explore how the ferroptosis inducer RSL3 regulates the abnormal biological behaviour of KCs at both cellular and animal levels and establish ferroptosis inhibitors as controls.

CONCLUSIONS

This study confirms the existence of ferroptosis in psoriatic lesions, which may be inversely correlated with disease severity. The ferroptosis inducer RSL3 ameliorated psoriatic symptoms by improving the abnormal biological behaviour of KCs.

Percutaneous Delivery of Hederacoside C-Loaded Nanoliposome Gel Alleviates Psoriasiform Skin Inflammation through the CCL17/Treg Axis

Psoriasis is a chronic, recurrent, and inflammatory skin disease. Topical agents, which can avoid the adverse effects of systemic treatment, are the first-choice therapy for patients with mild-to-moderate psoriasis. Hederacoside C (HSC) with anti-inflammatory properties has been used to treat some inflammatory diseases. We speculated that HSC might also be effective for psoriasis treatment. However, topical application of HSC for psoriasis treatment is challenging because of its low water solubility and poor skin permeability. Therefore, it is important to effectively deliver HSC percutaneously using certain biomaterials. Here we constructed a hydroxypropyl-β-cyclodextrin-coated liposome gel formulation for the loading and percutaneously delivering of HSC, referred to as HSC-Lipo@gel. The characterization, stability, release properties, and mechanical or transdermal features of the HSC-Lipo@gel were evaluated. Its therapeutic potential was also demonstrated using mouse models of IMQ-induced psoriasis. We found that HSC-Lipo@gel effectively improved the skin permeability of HSC with the property of good stability and sustained release. Importantly, HSC-Lipo@gel showed higher efficacy than HSC@gel without liposomes in alleviating psoriatic skin lesions. It attenuated epidermal hyperplasia and suppressed expression of IL-17A, TNF-α, IL-6, and IL-23 in lesional skin. Interestingly, HSC-Lipo@gel reduced the expression of CC chemokine ligand 17 (CCL17), but not CCL22, in the skin. Especially, HSC-Lipo@gel inhibited CCL17 expression by skin dendritic cells while increasing regulatory T cells (Tregs) in both skin and draining lymph nodes of psoriatic mice. Administration of CCL17 resulted in severe skin lesions and reduced CD4+FoxP3+ Tregs in psoriatic mice previously treated with HSC-Lipo@gel. Finally, HSC or HSC-Lipo also suppressed the CCL17 production by dendritic cells in vitro. Therefore, HSC-Lipo@gel alleviated psoriasiform skin inflammation by increasing cutaneous Tregs via downregulation of the expression of CCL17, but not CCL22. Thus, HSC-Lipo@gel may be a stable, highly permeable, and effective system for topical treatment of psoriasis.

Intradermal Injection of a Thermoresponsive Polymeric Dexamethasone Prodrug (ProGel-Dex) Ameliorate Dermatitis in an Imiquimod (IMQ)-Induced Psoriasis-like Mouse Model

Psoriasis is a chronic immune-mediated inflammatory skin disease, affecting ∼ 3% of the US population. Although multiple new systemic therapies have been introduced for the treatment of psoriatic skin disease, topical and intralesional glucocorticoids (GCs) continue to be used as effective psoriasis therapies. Their clinical utility, however, has been hampered by significant adverse effects, including skin atrophy and pigmentation as well as elevated blood glucose levels and hypertension. To mitigate these limitations, we have developed a N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-based thermoresponsive dexamethasone (Dex) prodrug (ProGel-Dex) and assessed its therapeutic efficacy and safety in an imiquimod (IMQ)-induced psoriasis-like (PL) mouse model. ProGel-Dex was intradermally administered once at three dosing levels: 0.5, 1.0, and 2.0 mg/kg/day Dex equivalent at the beginning of the study. PL mice were also treated with daily topical saline or Dex, which were used as control groups. Treatment of PL mice with ProGel-Dex dosed at 0.5 mg/kg/day resulted in a significant reduction in scaling and erythema. Improvement in gross pathology scores, skin histological scores, and serum cytokine levels was also observed. Interestingly, for mice treated with ProGel-Dex at 1.0 and 2.0 mg/kg/day Dex equivalent, only improvement in skin erythema was observed. GC-associated side effects, such as elevation of serum alanine aminotransferase (ALT) and amylase levels and body weight loss, were not observed in mice treated with ProGel-Dex at 0.5 and 1.0 mg/kg/day Dex equivalent. Collectively, these results demonstrate the efficacy and improved safety of ProGel-Dex in treating psoriatic skin lesions when compared to topical Dex treatment, supporting its translational potential for clinical management of lesional skin psoriasis.

Development of Imiquimod-induced HaCaT-THP-1 co-culture for modeling of psoriasis

Psoriasis is one of the most prevalent and chronic inflammatory disease of the skin, associated with disrupted barrier function. Currently, a widely accepted, generally usable cell culture model has not been developed yet. In the present work, we aimed to establish a co-culture model with human keratinocyte (HaCaT) and human monocyte cells (THP-1) induced by Imiquimod (IMQ), which acts on the TLR7 receptor. The role of TLR7 expressed on THP-1 cells was confirmed by immunofluorescence staining of NF-κB activation. Chloroquine (CH) was used as a receptor inhibitor, in the presence or absence of which the NF-κB pathway was activated. We determined the most effective proliferation-stimulating IMQ concentration by RTCA method and the hyperproliferative effect was investigated by wound-healing test. The effect of IMQ was compared with the effects of the anthocyanin (AC) components from the anti-inflammatory sour cherry extract that we have already studied. We found that IMQ significantly increased the migration rate however, the combined treatment resulted in a decreased migration rate compared to the IMQ treatment alone. Inflammatory cytokines were measured from the supernatant of co-culture by ELISA. During the development of the co-culture intended to model psoriasis, we confirmed the induction effect of IMQ and in the case of AC treatment, we supported the stabilizing effect of the barrier.

Neutrophil extracellular traps promote macrophage inflammation in psoriasis

Psoriasis is a chronic inflammatory skin disease connected with immune dysregulation. Macrophages are key inflammatory cells in psoriasis but the specific mechanism of their activation is not fully understood. Neutrophil extracellular traps (NETs) have been shown to regulate macrophage function. Here, we found that NET deposition was increased in psoriasis lesions. Peptidylarginine deaminase 4 (PAD4, a key enzyme for NET formation) deficiency attenuated skin lesions and inflammation in an imiquimod-induced psoriatic mouse model. Furthermore, the STING signaling pathway was markedly activated in psoriasis and abolished by PAD4 deficiency. PAD4-deficient mice treated with the STING agonist DMXAA exhibited more severe symptoms and inflammation than control mice. Mechanistically, the STING inhibitor C-176 inhibited NET-induced macrophage inflammation and further inhibited the proliferation of HaCaT cells. Our findings suggest an important role of NETs in the pathogenesis of psoriasis, and activation of macrophage STING/NF-κB signaling pathway might involve in NETs related psoriasis.

Extending the IMQ Model: Deep Characterization of the Human TLR7 Response for Early Drug Development

Imiquimod (IMQ; brand name Aldara®) is a registered topical agent that has been proven to induce local inflammation via the Toll-like receptor (TLR)7 pathway. The purpose of this study was to characterize TLR7-mediated inflammation following 7 days (168 h) of topical IMQ exposure in healthy volunteers, and to compare the effects of short exposure (48 h-72 h) with prolonged exposure (120 h-168 h). IMQ (100mg) was applied under occlusion to 5 different tape-stripped treatment sites on the back of 10 healthy participants for a maximum of 7 consecutive days. Erythema and skin perfusion were measured daily up to 168h. Biopsies for immunohistochemical staining and RNA sequencing were collected at 0h, 48h, 72h, 120h and 168h post IMQ application. IMQ triggered an inflammatory response starting at 48h after application, including erythema and perfusion of the skin. At the transcriptomic level, IMQ induced TLR7 signalling, IRF involvement and activation of TNF signalling via NF-κB. Furthermore, an enhanced inflammatory response at the cellular level was observed after prolonged IMQ exposure, with cellular infiltration of dendritic cells, macrophages and T cells which was also corroborated by transcriptomic profiles. No difference was found in the erythema and perfusion response after 168h of IMQ exposure compared to 72h. Prolonged IMQ exposure revealed enhanced cellular responses and additional pathways with modulated activity compared to short exposure and can therefore be of interest as a model for investigational compounds targeting innate and adaptive immune responses.

Green preparation and evaluation of the anti-psoriatic activity of vesicular elastic nanocarriers of kojic acid from Aspergillus oryzae N12: Repurposing of a dermo-cosmetic lead

Psoriasis is a skin disorder characterized by impaired epidermal differentiation that is regularly treated by systemic drugs with undesirable side effects. Based on its anti-inflammatory, antiproliferative and anti-melanoma attributes, the fungal metabolite kojic acid represents an attractive candidate for anti-psoriatic research. The present work aims to investigate an efficient topical bio-friendly vesicular system loaded with kojic acid isolated from Aspergillus oryzae as an alternative way for the management of psoriasis to avoid systemic toxicity. Kojic acid-loaded spanlastics were prepared by ethanol injection technique, employing span 60 along with brij 35 and cremophor rh40 as edge activators, with the complete in vitro characterization of the developed nanoplatform. The selected formulation displayed a spherical morphology, an optimum particle size of 234.2 ± 1.65 nm, high entrapment efficiency (87.4% ± 0.84%) and significant sustained drug release compared with the drug solution. In vivo studies highlighted the superior relief of psoriasis symptoms and the ability to maintain healthy skin with the least changes in mRNA expression of inflammatory cytokines, achieved by the developed nanoplatform compared to kojic acid solution. Moreover, the in vivo histopathological studies confirmed the safety of the topically applied spanlastics. In addition, the molecular mechanism was approached through in vitro assessment of cathepsin S and PDE-4 inhibitory activities and in silico investigation of kojic acid docking in several anti-psoriatic drug targets. Our results suggest that a topically applied vesicular system loaded with kojic acid could lead to an expansion in the dermo-cosmetic use of kojic acid as a natural bio-friendly alternative for systemic anti-psoriatic drugs.

Unveiling the immune-modulating power of THz-FEL irradiation

As terahertz (THz) technology advances, the interaction between THz radiation and the living body, particularly its effects on the immune system, has attracted extensive attention but remains poorly understood. This study firstly elucidated that exposure to 3 THz-FEL radiation markedly suppressed contact hypersensitivity reactions in mice induced by DNFB, as evidenced by a reduction in ear thickness and a discernible recovery in the Th1/Th2 cell balance. 3 THz irradiation led to cellular stress in the irradiated skin locale, increasing the levels of IL-4 and IL-10 and modulating the activity and migration of dendritic cells and mast cells. Furthermore, THz irradiation precipitated a rapid alteration in the skin lipidome, altering several categories of bioactive lipids. These findings offer new insights into the immunomodulatory effects of THz radiation on living organisms and the potential underlying mechanisms, with implications for the development of therapeutic approaches in managing skin allergic diseases.

Berberine, a natural alkaloid: Advances in its pharmacological effects and mechanisms in the treatment of autoimmune diseases

The rising prevalence of autoimmune diseases poses a significant challenge to global public health. Continual exploration of natural compounds for effective treatments for autoimmune diseases is crucial. Berberine, a benzylisoquinoline alkaloid, is a bioactive component found in various medicinal plants, exhibiting diverse pharmacological properties. This review aims to consolidate the current understanding of berberine's pharmacological effects and mechanisms in addressing four autoimmune diseases: rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease, and psoriasis. Overall, as a traditional Chinese medicinal preparation, berberine shows promise as an effective and safe treatment for autoimmune diseases. However, further comprehensive studies, particularly clinical trials, are essential to elucidate additional mechanisms and molecular targets, as well as to assess the efficacy and safety of berberine in treating these autoimmune diseases.

Preclinical techniques for drug discovery in psoriasis

Psoriasis is a chronic, inflammatory, papulosquamous, noncontagious disease characterized by scaly, demarcated erythematous plaque, affecting skin, nails, and scalp. The IL-23/Th17 axis is the main operator in the development of psoriasis. Psoriasis is affecting worldwide, and new treatment options are urgently needed. Various local and systemic treatments are available for psoriasis but they only provide symptomatic relief because of numerous unknown mechanisms. Clinical trials demand overwhelming resources; therefore, drug development predominantly depends on the in-vivo, in-vitro, and ex-vivo techniques. Immediate attention is required to develop experimental techniques that completely imitate human psoriasis to assist drug development. This review portrays the various in-vivo, in-vitro, and ex-vivo techniques used in psoriasis research. It describes these techniques' characteristics, pathological presentations, and mechanisms. The experimental techniques of psoriasis provide significant information on disease progression mechanisms and possible therapeutic targets. However, until now, it has been challenging to invent a timely, affordable model that precisely imitates a human disease. Only the xenotransplantation model is reckoned as the closer, that mimics the complete genetic, and immunopathogenic event. Imiquimod-induced psoriasis and HaCat cell lines are popular among researchers because of their convenience, ease of use, and cost-effectiveness. There need to further improve the experimental techniques to best serve the disease imitation and meet the research goal.

High throughput screening identifies repurposable drugs for modulation of innate and acquired immune responses

A balanced immune system is essential to maintain adequate host defense and effective self-tolerance. While an immune system that fails to generate appropriate response will permit infections to develop, uncontrolled activation may lead to autoinflammatory or autoimmune diseases. To identify drug candidates capable of modulating immune cell functions, we screened 1200 small molecules from the Prestwick Chemical Library for their property to inhibit innate or adaptive immune responses. Our studies focused specifically on drug interactions with T cells, B cells, and polymorphonuclear leukocytes (PMNs). Candidate drugs that were validated in vitro were examined in preclinical models to determine their immunomodulatory impact in chronic inflammatory diseases, here investigated in chronic inflammatory skin diseases. Using this approach, we identified several candidate drugs that were highly effective in preclinical models of chronic inflammatory disease. For example, we found that administration of pyrvinium pamoate, an FDA-approved over-the-counter anthelmintic drug, suppressed B cell activation in vitro and halted the progression of B cell-dependent experimental pemphigoid by reducing numbers of autoantigen-specific B cell responses. In addition, in studies performed in gene-deleted mouse strains provided additional insight into the mechanisms underlying these effects, for example, the receptor-dependent actions of tamoxifen that inhibit immune-complex-mediated activation of PMNs. Collectively, our methods and findings provide a vast resource that can be used to identify drugs that may be repurposed and used to promote or inhibit cellular immune responses.

p38α deficiency ameliorates psoriasis development by downregulating STAT3-mediated keratinocyte proliferation and cytokine production

Psoriasis is characterized by keratinocyte (KC) hyperproliferation and inflammatory cell infiltration, but the mechanisms remain unclear. In an imiquimod-induced mouse psoriasiform model, p38 activity is significantly elevated in KCs and p38α specific deletion in KCs ameliorates skin inflammation. p38α signaling promotes KC proliferation and psoriasis-related proinflammatory gene expression during psoriasis development. Mechanistically, p38α enhances KC proliferation and production of inflammatory cytokines and chemokines by activating STAT3. While p38α signaling in KCs does not affect the expression of IL-23 and IL-17, it substantially amplifies the IL-23/IL-17 pathogenic axis in psoriasis. The therapeutic effect of IL-17 neutralization is associated with decreased p38 and STAT3 activities in KCs and targeting the p38α-STAT3 axis in KCs ameliorates the severity of psoriasis. As IL-17 also highly activates p38 and STAT3 in KCs, our findings reveal a sustained signaling circuit important for psoriasis development, highlighting p38α-STAT3 axis as an important target for psoriasis treatment.

Targeting the Skin: The Study of a Bottlebrush Polymer-Antisense Oligonucleotide Conjugate in a Psoriasis Mouse Model

The investigation of gene regulation therapeutics for the treatment of skin-related diseases is rarely explored in part due to inefficient systemic delivery. In this study, a bottlebrush polymer-antisense oligonucleotide (ASO) conjugate, termed pacDNA, designed to target IL-17 receptor A (IL-17RA), which is involved in psoriasis pathogenesis is presented. Systemic administration of pacDNA led to its accumulation in epidermis, dermis, and hypodermis of mouse skin, reduced IL-17RA gene expression in skin, and significantly reversed the development of imiquimod (IMQ)-induced psoriasis in a mouse model. These findings highlight the potential of the pacDNA as a promising nanoconstruct for systemic oligonucleotide delivery to the skin and for treating psoriasis and other skin-related disorders through systemic administration.

Cellular spermine targets JAK signaling to restrain cytokine-mediated autoimmunity

Prolonged activation of the type I interferon (IFN-I) pathway leads to autoimmune diseases such as systemic lupus erythematosus (SLE). Metabolic regulation of cytokine signaling is critical for cellular homeostasis. Through metabolomics analyses of IFN-β-activated macrophages and an IFN-stimulated-response-element reporter screening, we identified spermine as a metabolite brake for Janus kinase (JAK) signaling. Spermine directly bound to the FERM and SH2 domains of JAK1 to impair JAK1-cytokine receptor interaction, thus broadly suppressing JAK1 phosphorylation triggered by cytokines IFN-I, IFN-II, interleukin (IL)-2, and IL-6. Peripheral blood mononuclear cells (PBMCs) from individuals with SLE showing decreased spermine concentrations exhibited enhanced IFN-I and lupus gene signatures. Spermine treatment attenuated autoimmune pathogenesis in SLE and psoriasis mice and reduced IFN-I signaling in monocytes from individuals with SLE. We synthesized a spermine derivative (spermine derivative 1 [SD1]) and showed that it had a potent immunosuppressive function. Our findings reveal spermine as a metabolic checkpoint for cellular homeostasis and a potential immunosuppressive molecule for controlling autoimmune disease.

Nicotinamide Suppresses Hyperactivation of Dendritic Cells to Control Autoimmune Disease through PARP Dependent Signaling

Dendritic cells (DCs) are crucial in initiating and shaping both innate and adaptive immune responses. Clinical studies and experimental models have highlighted their significant involvement in various autoimmune diseases, positioning them as promising therapeutic targets. Nicotinamide (NAM), a form of vitamin B3, with its anti-inflammatory properties, has been suggested, while the involvement of NAM in DCs regulation remains elusive. Here, through analyzing publicly available databases, we observe substantial alterations in NAM levels and NAM metabolic pathways during DCs activation. Furthermore, we discover that NAM, but not Nicotinamide Mononucleotide (NMN), significantly inhibits DCs over-activation in vitro and in vivo. The suppression of DCs hyperactivation effectively alleviates symptoms of psoriasis. Mechanistically, NAM impairs DCs activation through a Poly (ADP-ribose) polymerases (PARPs)-NF-κB dependent manner. Notably, phosphoribosyl transferase (NAMPT) and PARPs are significantly upregulated in lipopolysaccharide (LPS)-stimulated DCs and psoriasis patients; elevated NAMPT and PARPs expression in psoriasis patients correlates with higher psoriasis area and severity index (PASI) scores. In summary, our findings underscore the pivotal role of NAM in modulating DCs functions and autoimmune disorders. Targeting the NAMPT-PARP axis emerges as a promising therapeutic approach for DC-related diseases.

A human STAT3 gain-of-function variant drives local Th17 dysregulation and skin inflammation in mice

Germline gain-of-function (GOF) variants in STAT3 cause an inborn error of immunity associated with early-onset poly-autoimmunity and immune dysregulation. To study tissue-specific immune dysregulation, we used a mouse model carrying a missense variant (p.G421R) that causes human disease. We observed spontaneous and imiquimod (IMQ)-induced skin inflammation associated with cell-intrinsic local Th17 responses in STAT3 GOF mice. CD4+ T cells were sufficient to drive skin inflammation and showed increased Il22 expression in expanded clones. Certain aspects of disease, including increased epidermal thickness, also required the presence of STAT3 GOF in epithelial cells. Treatment with a JAK inhibitor improved skin disease without affecting local Th17 recruitment and cytokine production. These findings collectively support the involvement of Th17 responses in the development of organ-specific immune dysregulation in STAT3 GOF and suggest that the presence of STAT3 GOF in tissues is important for disease and can be targeted with JAK inhibition.

Pongamia pinnata seed extract-mediated green synthesis of silver nanoparticle loaded nanogel for estimation of their antipsoriatic properties

This research describes the eco-friendly green synthesis of silver nanoparticles employing Pongamia pinnata seed extracts loaded with nanogel formulations (AgNPs CUD NG) to improve the retention, accumulation, and the penetration of AgNPs into the epidermal layer of psoriasis. AgNPs were synthesized using the Box-Behnken design. Optimized AgNPs and AgNPs CUD NG were physico-chemically evaluated using UV-vis spectroscopy, SEM, FT-IR, PXRD, viscosity, spreadability, and retention studies. It was also functionally assessed using an imiquimod-induced rat model. The entrapment efficiency of AgNPs revealed ~ 79.35%. Physico-chemical parameters announced the formation of AgNPs via surface plasmon resonance and interaction between O-H, C = O, and amide I carbonyl group of protein extract and AgNO3. Optimized AgNPs showed spherical NPs ~ 116 nm with better physical stability and suitability for transdermal applications. AgNPs CUD NG revealed non-Newtonian, higher spreadability, and better extrudability, indicating its suitability for a transdermal route. AgNPs CUD NG enhanced the retention of AgNPs on the psoriatic skin compared to normal skin. Optimized formulations exhibit no irritation by the end of 72 h, indicating formulation safety. AgNPs CUD NG at a dose of 1 FTU showed significant recovery from psoriasis with a PASI score of ~ 0.8 compared to NG base and marketed formulations. Results indicated that seed extract-assisted AgNPs in association with CUD-based NG formulations could be a promising nanocarrier for psoriasis and other skin disorders.

Ameliorative effects of topical ramelteon on imiquimod-induced psoriasiform inflammation in mice

Psoriasis is a long-lasting, immune-related inflammatory skin disease that affects 2-3% of the global population. It is distinguished by erythematous, silvery, and scaly patches. Ramelteon is a type of melatonin agonist that is used to treat insomnia. It has enhanced non-classical immunomodulatory and anti-inflammatory activities. The aim of the study is to assess the ameliorative effects of topical ramelteon on imiquimod (IMQ)-aggravated psoriasiform-like dermatosis in mice. The 32 albino mouse males were placed into six groups of eight animals, all of them. With the exception of the control group, all groups gained a once-a-day regimen of topical imiquimod 5% cream at a dose of 62.5 mg for eight uninterrupted days, while mice in the control group gained vaseline-based ointment alternately. Immediately after an 8-day induction period in the imiquimod group, mice in the clobetasol and ramelteon treatment groups obtained a twice-daily regimen of topical clobetasol propionate 0.05% ointment and 0.1% ointment, respectively, for a further 8 days. This extends the total duration of the experimental study to 16 continuous days. The findings of our study found that ramelteon significantly mitigated the concentrations of inflammatory cytokines in the skin tissue, including interleukin (IL)-6, IL-17A, IL-23, tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF), as well as the scores associated with psoriatic lesions, including erythema, scaling, skin thickening, ear thickness, and overall cumulative PASI scores. Additionally, the anti-inflammatory impact of ramelteon was achieved by markedly increasing IL-10 levels in the skin tissue and correcting cutaneous histopathological alterations. Ramelteon ointment (0.1%) was comparable to that of clobetasol (0.05%) ointment in alleviating a mouse model of imiquimod-induced psoriasiform inflammation; this is probably due to its potential anti-inflammatory and immunomodulatory activities. Therefore, ramelteon could be a good additive option for therapeutic management of immune-triggered inflammatory conditions such as psoriasis.

Are periodontitis and psoriasis associated? A pre-clinical murine model

AIM

To investigate the bidirectional influence between periodontitis and psoriasis, using the respective experimental models of ligature- and imiquimod-induced diseases on murine models.

MATERIALS AND METHODS

Thirty-two C57/BL6J mice were randomly allocated to four experimental groups: control (P- Pso-), ligature-induced periodontitis (P+ Pso-), imiquimod-induced psoriasis (P- Pso+) and periodontitis and psoriasis (P+ Pso+). Samples (maxilla, dorsal skin and blood) were harvested immediately after death. Measures of periodontitis (distance between the cemento-enamel junction and alveolar bone crest [CEJ-ABC] and the number of osteoclasts) and psoriasis (epidermal thickness and infiltrate cell [/0.03mm2]) severity as well as systemic inflammation (IL-6, IL-17A, TNF-α) were collected.

RESULTS

The P+ Pso+ group exhibited the most severe experimental periodontitis and psoriasis, with the highest values of CEJ-ABC, number of osteoclasts, epidermal thickness and infiltrate cells in the dorsal skin, as well as the highest blood cytokine concentration. The P+ Pso- group presented with higher cell infiltrate (/0.03mm2) compared to the control group (p <.05), while the P- Pso+ group showed substantially higher alveolar bone loss (CEJ-ABC) than the control group (p <.05).

CONCLUSIONS

Experimental periodontitis may initiate and maintain psoriasiform skin inflammation and, vice versa, experimental psoriasis may contribute to the onset of periodontitis. In a combined model of the diseases, we propose a bidirectional association between periodontitis and psoriasis via systemic inflammation.

Topical application of a BCL-2 inhibitor ameliorates imiquimod-induced psoriasiform dermatitis by eliminating senescent cells

BACKGROUND

Psoriasis is an inflammatory skin disease with unclear pathogenesis and unmet therapeutic needs.

OBJECTIVE

To investigate the role of senescent CD4+ T cells in psoriatic lesion formation and explore the application of senolytics in treating psoriasis.

METHODS

We explored the expression levels of p16INK4a and p21, classical markers of cellular senescence, in CD4+ T cells from human psoriatic lesions and imiquimod (IMQ)-induced psoriatic lesions. We prepared a senolytic gel using B-cell lymphoma 2 (BCL-2) inhibitor ABT-737 and evaluated its therapeutic efficacy in treating psoriasis.

RESULTS

Using multispectrum immunohistochemistry (mIHC) staining, we detected increased expression levels of p16INK4a and p21 in CD4+ T cells from psoriatic lesions. After topical application of ABT-737 gel, significant alleviation of IMQ-induced psoriatic lesions was observed, with milder pathological alterations. Mechanistically, ABT-737 gel significantly decreased the percentage of senescent cells, expression of T cell receptor (TCR) α and β chains, and expression of Tet methylcytosine dioxygenase 2 (Tet2) in IMQ-induced psoriatic lesions, as determined by mIHC, high-throughput sequencing of the TCR repertoire, and RT-qPCR, respectively. Furthermore, the severity of psoriatic lesions in CD4creTet2f/f mice was milder than that in Tet2f/f mice in the IMQ-induced psoriasis model.

CONCLUSION

We revealed the roles of senescent CD4+ T cells in developing psoriasis and highlighted the therapeutic potential of topical ABT-737 gel in treating psoriasis through the elimination of senescent cells, modulation of the TCR αβ repertoire, and regulation of the TET2-Th17 cell pathway.

Features of the CD1 gene family in rodents and the uniqueness of the immune system of naked mole-rat

Cluster of Differentiation 1 (CD1) proteins are widely expressed throughout jawed vertebrates and present lipid antigens to specific CD1-restricted T lymphocytes. CD1 molecules play an important role in immune defense with the presence or absence of particular CD1 proteins frequently associated with the functional characteristics of the immune system. Here, we show the evolution of CD1 proteins in the Rodentia family and the diversity among its members. Based on the analysis of CD1 protein-coding regions in rodent genomes and the reconstruction of protein structures, we found that Heterocephalus glaber represents a unique member of the suborder Hystricomorpha with significant changes in protein sequences and structures of the CD1 family. Multiple lines of evidence point to the absence of CD1d and CD1e and probably a dysfunctional CD1b protein in Heterocephalus glaber. In addition, the impact of CD1d loss on the CD1d/Natural killer T (NKT) cell axis in the naked mole-rat and its potential implications for immune system function are discussed in detail.

Interleukin-38 overexpression in keratinocytes limits desquamation but does not affect the global severity of imiquimod-induced skin inflammation in mice

Psoriasis is a common chronic inflammatory skin disease that significantly impacts the patients' quality of life. Recent studies highlighted the function of the interleukin (IL)-1 family member IL-38 in skin homeostasis and suggested an anti-inflammatory role for this cytokine in psoriasis. In this study, we generated mice specifically overexpressing the IL-38 protein in epidermal keratinocytes. We confirmed IL-38 overexpression in the skin by Western blotting. We further detected the protein by ELISA in the plasma, as well as in conditioned media of skin explants isolated from IL-38 overexpressing mice, indicating that IL-38 produced in the epidermis is released from keratinocytes and can be found in the circulation. Unexpectedly, epidermal IL-38 overexpression did not impact the global severity of imiquimod (IMQ)-induced skin inflammation, Similarly, keratinocyte activation and differentiation in IMQ-treated skin were not affected by increased IL-38 expression and there was no global effect on local or systemic inflammatory responses. Nevertheless, we observed a selective inhibition of CXCL1 and IL-6 production in response to IMQ in IL-38 overexpressing skin, as well as reduced Ly6g mRNA levels, suggesting decreased neutrophil infiltration. Epidermal IL-38 overexpression also selectively affected the desquamation process during IMQ-induced psoriasis, as illustrated by reduced plaque formation. Taken together, our results validate the generation of a new mouse line allowing for tissue-specific IL-38 overexpression. Interestingly, epidermal IL-38 overexpression selectively affected specific disease-associated readouts during IMQ-induced psoriasis, suggesting a more complex role of IL-38 in the inflamed skin than previously recognized. In particular, our data highlight a potential involvement of IL-38 in the regulation of skin desquamation.

Lazy neutrophils - a lack of DGAT1 reduces the chemotactic activity of mouse neutrophils

BACKGROUND

Neutrophils are key players in the innate immune system, actively migrating to sites of inflammation in the highly energetic process of chemotaxis. In this study, we focus on the role of acyl-CoA: diacylglycerol acyltransferase 1 (DGAT1), an enzyme that catalyzes the synthesis of triglycerides, the major form of stored energy, in neutrophil chemotaxis.

METHODS AND RESULTS

Using a mouse model of psoriasis, we show that DGAT1-deficiency reduces energy-demanding neutrophil infiltration to the site of inflammation, but this inhibition is not caused by decreased glycolysis and reduced ATP production by neutrophils lacking DGAT1. Flow cytometry and immunohistochemistry analysis demonstrate that DGAT1 also does not influence lipid accumulation in lipid droplets during inflammation. Interestingly, as has been shown previously, a lack of DGAT1 leads to an increase in the concentration of retinoic acid, and here, using real-time PCR and publicly-available next-generation RNA sequencing datasets, we show the upregulation of retinoic acid-responsive genes in Dgat1KO neutrophils. Furthermore, supplementation of WT neutrophils with exogenous retinoic acid mimics DGAT1-deficiency in the inhibition of neutrophil chemotaxis in in vitro transwell assay.

CONCLUSIONS

These results suggest that impaired skin infiltration by neutrophils in Dgat1KO mice is a result of the inhibitory action of an increased concentration of retinoic acid, rather than impaired lipid metabolism in DGAT1-deficient mice.

Tonic type 2 immunity is a critical tissue checkpoint controlling autoimmunity in the skin

Immunoregulatory mechanisms established in the lymphoid organs are vital for preventing autoimmunity. However, the presence of similar mechanisms in non-lymphoid tissues remains unclear. Through transcriptomic and lipidomic analyses, we find a negative association between psoriasis and fatty acid metabolism, as well as Th2 signature. Homeostatic expression of liver X receptor (LXR) and peroxisome proliferator-activated receptor gamma (PPARγ) is essential for maintaining fatty acid metabolism and for conferring resistance to psoriasis in mice. Perturbation of signal transducer and activator of transcription 6 (STAT6) diminishes the homeostatic levels of LXR and PPARγ. Furthermore, mice lacking STAT6, interleukin 4 receptor alpha (IL-4Rα), or IL-13, but not IL-4, exhibit increased susceptibility to psoriasis. Under steady state, innate lymphoid cells (ILCs) are the primary producers of IL-13. In human skin, inhibiting tonic type 2 immunity exacerbates psoriasis-like inflammation and IL-17A, while activating LXR or PPARγ inhibits them. Hence, we propose that tonic type 2 immunity, driven by IL-13-producing ILCs, represents a crucial tissue checkpoint that represses autoimmunity and maintains lipid homeostasis in the skin.

Oral Exposure to Low Concentration of Fumonisin B2, but Not Fumonisin B1, Significantly Exacerbates the Pathophysiology of Imiquimod-Induced Psoriasis in Mice

This study aimed to determine whether oral fumonisin exposure contributes to the development of psoriasis. Oral administration of fumonisin B1 (FB1, 0.1 mg/kg) or fumonisin B2 (FB2, 0.1 mg/kg) was conducted for 10 days, in addition to the induction of psoriatic symptoms through topical application of 5% imiquimod cream from day 6 to day 10 (5 days) in female BALB/c mice. The results demonstrated that oral administration of FB2 significantly exacerbated psoriatic symptoms, including skin thickness, itching behavior, transepidermal water loss, immune cell infiltration in the dermis, and proinflammatory cytokine production. However, no changes were observed following exposure to FB1. Our results confirm that oral exposure to FB2 adversely affects the pathogenesis of psoriasis by increasing skin thickness and impairing barrier function.

Resident memory T cells in dirty mice suppress innate cell activation and infiltration into the skin following stimulation with alarmins

Trm cells are sequestered at barrier tissues as a swift first line defense against peripheral reinfections in both antigen dependent and antigen independent bystander modes. Trm cells are also capable of mediating autoimmune diseases, such as psoriasis, wherein autoreactive Trm cells are aberrantly activated. To quickly combat infections, activated Trm cells can stimulate the influx and activation of memory T cells and innate immune cells. However, there is significant heterogeneity in the inflammatory responses that Trm cell populations can induce, specifically in the activation of the innate profile. Most studies to date have utilized a reductionist approach to examine single Trm populations, specific pathogens, and defined tissues. Herein, we adopted a more holistic approach utilizing barrier-free 'dirty' mice to profile activated innate cells attracted to the skin in the presence of quiescent cutaneous Trm cells. Notably, dirty mice are a more human predictive model due to having a diverse microbial experience that leads to the development of a complete complement of Trm cells in the skin. We demonstrate that in the dirty mouse model mice have a significant reduction in cutaneous neutrophils and monocytes compared to SPF mice following local treatment with two separate innate stimuli. These findings reveal that cutaneous Trm cells have the capacity to temper the innate immune response and further substantiate the implication that Trm cells are heterogenous in their functions depending in large part on their tissue residency. However, in an autoimmune microenvironment Trm cells are capable of recruiting innate cells to the site of an exposure to a damage-associated molecular pattern. Likely due to the imbalance of IL-17 and IFN-γ.

Evaluation of Kynu, Defb2, Camp, and Penk Expression Levels as Psoriasis Marker in the Imiquimod-Induced Psoriasis Model

Background

Psoriasis is a noncontagious auto-inflammatory chronic skin disease. So far, some of the inflammatory genes were upregulated in mouse model of psoriasis. This study examined changes in skin mRNA expression of L-kynureninase (Kynu), cathelicidin antimicrobial peptide (Camp), beta-defensin 2 (Defb2), and proenkephalin (Penk) in a mouse model of imiquimod-induced psoriasis.

Materials and Methods

Tree groups of C57BL/6 female mice were allocated. The imiquimod (IMQ) cream was administered to the mice dorsal skin of the two groups to induce psoriatic inflammation. In the treatment group, IMQ was administered 10 min after hydrogel-containing M7 anti-IL-17A aptamer treatment. Vaseline (Vas) was administered to the negative control group. The psoriatic skin lesions were evaluated based on the psoriasis area severity index (PASI) score, histopathology, and mRNA expression levels of Kynu, Camp, Defb2, and Penk using real-time PCR. In order to assess the systemic response, the spleen and lymph node indexes were also evaluated.

Results

The PASI and epidermal thickness scores were 6.01 and 1.96, respectively, in the IMQ group, and they significantly decreased after aptamer administration to 1.15 and 0.90, respectively (P < 0.05). Spleen and lymph node indexes showed an increase in the IMQ group, followed by a slight decrease after aptamer treatment (P > 0.05). Additionally, the mRNA expression levels of Kynu, Defb2, Camp, and Penk genes in the IMQ-treated region showed a significant 2.70, 4.56, 3.29, and 2.61-fold increase relative to the Vas mice, respectively (P < 0.05). The aptamer-treated region exhibited a significant decrease in these gene expression levels (P < 0.05). A positive correlation was found between Kynu, Penk, and Camp expression levels and erythema, as well as Camp expression with PASI, scaling, and thickness (P < 0.05).

Conclusion

According to our results, it seems that Kynu, Camp, and Penk can be considered appropriate markers for the evaluation of psoriasis in IMQ-induced psoriasis. Also, the anti-IL-17 aptamer downregulated these important genes in this mouse model.

Itch and Pain Behaviors in Irritant Contact Dermatitis Produced by Sodium Lauryl Sulfate in Mice

Irritant contact dermatitis (ICD) is a nonspecific skin inflammation caused by irritants, leading to itch and pain. We tested whether differential responses to histamine-dependent and -independent pruritogens can be evoked in ICD induced by sodium lauryl sulfate (SLS). An ICD mouse model was established with 5% SLS in acetone versus a vehicle topically applied for 24 h to the cheek. Site-directed itch- and pain-like behaviors, occurring spontaneously and in response to mechanical, thermal, and chemical stimuli (histamine, ß-alanine, BAM8-22, and bradykinin) applied to the cheek, were recorded before (day 0) and after irritant removal (days 1, 2, 3, and 4). Skin inflammation was assessed through visual scoring, ultrasound, and measurements of skin thickness. SLS-treated mice exhibited hyperalgesia-like behavior in response to mechanical and heat stimuli on day 1 compared to the controls. SLS mice exhibited more spontaneous wipes (pain) but not scratching bouts (itch) on day 1. Pruritogen injections caused more scratching but not wiping in SLS-treated mice compared to the controls. Only bradykinin increased wiping behavior compared to saline. SLS-treated mice developed noticeable erythema, scaling, and increased skin thickness on days 1 and 2. SLS induced cutaneous inflammation and behavioral signs of spontaneous pain and itching, hyperalgesia to mechanical and heat stimuli and a chemical algogen, and enhanced itch response to pruritogens. These sensory reactions preceded the inflammation peak and lasted up to two days.

Immune Stimulation with Imiquimod to Best Face SARS-CoV-2 Infection and Prevent Long COVID

Through widespread immunization against SARS-CoV-2 prior to or post-infection, a substantial segment of the global population has acquired both humoral and cellular immunity, and there has been a notable reduction in the incidence of severe and fatal cases linked to this virus and accelerated recovery times for those infected. Nonetheless, a significant demographic, comprising around 20% to 30% of the adult population, remains unimmunized due to diverse factors. Furthermore, alongside those recovered from the infection, there is a subset of the population experiencing persistent symptoms referred to as Long COVID. This condition is more prevalent among individuals with underlying health conditions and immune system impairments. Some Long COVID pathologies stem from direct damage inflicted by the viral infection, whereas others arise from inadequate immune system control over the infection or suboptimal immunoregulation. There are differences in the serum cytokines and miRNA profiles between infected individuals who develop severe COVID-19 or Long COVID and those who control adequately the infection. This review delves into the advantages and constraints associated with employing imiquimod in human subjects to enhance the immune response during SARS-CoV-2 immunization. Restoration of the immune system can modify it towards a profile of non-susceptibility to SARS-CoV-2. An adequate immune system has the potential to curb viral propagation, mitigate symptoms, and ameliorate the severe consequences of the infection.

Skin deep: Epithelial cell metabolism and chronic skin inflammation

Skin inflammation is potentiated by coordinated epithelial and immune cell metabolism. In this issue of Immunity, Subudhi and Konieczny et al. delineate how HIF1α regulates epithelial cell glycolysis during psoriasis. In turn, lactate is a byproduct that augments type 17 γδ T cell responses to sustain inflammatory skin disease.

Metabolic coordination between skin epithelium and type 17 immunity sustains chronic skin inflammation

Inflammatory epithelial diseases are spurred by the concomitant dysregulation of immune and epithelial cells. How these two dysregulated cellular compartments simultaneously sustain their heightened metabolic demands is unclear. Single-cell and spatial transcriptomics (ST), along with immunofluorescence, revealed that hypoxia-inducible factor 1α (HIF1α), downstream of IL-17 signaling, drove psoriatic epithelial remodeling. Blocking HIF1α in human psoriatic lesions ex vivo impaired glycolysis and phenocopied anti-IL-17 therapy. In a murine model of skin inflammation, epidermal-specific loss of HIF1α or its target gene, glucose transporter 1, ameliorated epidermal, immune, vascular, and neuronal pathology. Mechanistically, glycolysis autonomously fueled epithelial pathology and enhanced lactate production, which augmented the γδ T17 cell response. RORγt-driven genetic deletion or pharmacological inhibition of either lactate-producing enzymes or lactate transporters attenuated epithelial pathology and IL-17A expression in vivo. Our findings identify a metabolic hierarchy between epithelial and immune compartments and the consequent coordination of metabolic processes that sustain inflammatory disease.

Upregulated miR-374a-5p drives psoriasis pathogenesis through WIF1 downregulation and Wnt5a/NF-κB activation

BACKGROUND

Psoriasis is a chronic, inflammatory skin disease. MicroRNAs (miRNAs) are an abundant class of non-coding RNA molecules. Recent studies have shown that multiple miRNAs are abnormally expressed in patients with psoriasis. The upregulation of miR-374a-5p has been associated with psoriasis severity. However, the specific role of miR-374a-5p in the pathogenesis of psoriasis remain unclear.

METHODS

qRT-PCR was employed to validate the expression of miR-374a-5p in psoriatic lesions and in a psoriasis-like cell model constructed using a mixture of M5 (IL-17A, IL-22, OSM, IL-1α, and TNF-α). HaCaT cells were transfected with miR-374a-5p mimic/inhibitor, and assays including EdU, CCK-8, and flow cytometry were conducted to evaluate the effect of miR-374a-5p on cell proliferation. The expression of inflammatory cytokines IL-1β, IL-6, IL-8, and TNF-α was verified by qRT-PCR. Bioinformatics analysis and dual-luciferase reporter gene assay were performed to detect the downstream target genes and upstream transcription factors of miR-374a-5p, followed by validation of their expression through qRT-PCR and Western blotting. A psoriasis-like mouse model was established using imiquimod cream topical application. The psoriasis area and severity index scoring, hematoxylin-eosin histology staining, and Ki67 immunohistochemistry were employed to validate the effect of miR-374a-5p on the psoriatic inflammation phenotype after intradermal injection of miR-374a-5p agomir/NC. Additionally, the expression of pathway-related molecules and inflammatory factors such as IL-1β, IL-17a, and TNF-α was verified by immunohistochemistry.

RESULTS

Upregulation of miR-374a-5p was observed in psoriatic lesions and the psoriasis-like cell model. In vitro experiments demonstrated that miR-374a-5p not only promoted the proliferation of HaCaT cells but also upregulated the expression of inflammatory cytokines, including IL-1β, IL-6, IL-8, and TNF-α. Furthermore, miR-374a-5p promoted skin inflammation and epidermal thickening in the Imiquimod-induced psoriasis-like mouse model. Mechanistic studies revealed that miR-374a-5p led to downregulation of WIF1, thereby activating the Wnt5a/NF-κB signaling pathway. The transcription factor p65 encoded by RELA, as a subunit of NF-κB, further upregulated the expression of miR-374a-5p upon activation. This positive feedback loop promoted keratinocyte proliferation and abnormal inflammation, thereby facilitating the development of psoriasis.

CONCLUSION

Our findings elucidate the role of miR-374a-5p upregulation in the pathogenesis of psoriasis through inhibition of WIF1 and activation of the Wnt5a/NF-κB pathway, providing new potential therapeutic targets for psoriasis.

Novel effect of topical Roquinimex and its combination with Clobetasol on an imiquimod-induced model of psoriasis in mice

Psoriasis is a chronic inflammatory skin condition affecting multiple systems and the skin, with topical therapy representing the fundamental treatment modality for psoriasis. Investigate the effect of topical Roquinimex (ROQ) alone and combined with Clobetasol propionate (CLO) on imiquimod (IMQ)-induced mouse model as a novel approach to treating psoriasis. Sixty male Swiss Albino mice were divided into six groups of ten mice; all groups except the negative control received IMQ cream 5% (62.5 mg) as a once-daily topical application for six days. On the seventh day, five groups (except negative control) received one of the following treatments for eight days: no treatment (positive control), Petrolatum gel 15% as a twice-daily topical application (Petrolatum control), CLO 0.05% ointment once daily, ROQ ointment 1% w/w twice daily topically, topical preparation of 0.025% CLO ointment combined with ROQ ointment 0.5% w/w twice daily; the total duration of the study is 14 days. The clinical, pathological, and laboratory effects were then measured. The use of ROQ ointment alone or combined with CLO resulted in significant improvement in psoriasis lesions (measured by Baker's and PASI scores) compared to positive control groups (2.15±1.08, 1.60±0.61, 9.00±0.00, and 7.60±0.84, respectively for Baker's score) (1.50±1.08, 1.30±0.95, 11.70±0.48, 9.30±0.67, respectively for PASI score), a similar improvement seen for various inflammatory markers, including interleukin (IL)-10 (140.53±60.68, 285.63±92.16, 31.83±3.03, and 92.50±27.13 pg/ml, respectively), IL-17 (126.58±40.98, 124.26±61.40, 553.04±141.32, and 278.52±100.27 pg/ml, respectively), tumor necrosis factor-α (72.34±23.40, 30.11±7.01, 807.13±500.06, and 281.79±240.17 pg/ml, respectively), and vascular endothelial growth factor (109.71±29.35, 80.96±24.58, 552.20±136.63, 209.56±73.31 pg/ml and respectively). Roquinimex exerts its antipsoriatic effect through multiple mechanisms; its combination treatment with Clobetasol is a promising therapy for managing psoriasis.

Targeting STING in dendritic cells alleviates psoriatic inflammation by suppressing IL-17A production

Psoriasis is a common chronic inflammatory skin disease driven by the aberrant activation of dendritic cells (DCs) and T cells, ultimately leading to increased production of cytokines such as interleukin (IL)-23 and IL-17A. It is established that the cGAS-STING pathway is essential for psoriatic inflammation, however, the specific role of cGAS-STING signaling in DCs within this context remains unclear. In this study, we demonstrated the upregulation of cGAS-STING signaling in psoriatic lesions by analyzing samples from both clinical patients and imiquimod (IMQ)-treated mice. Using a conditional Sting-knockout transgenic mouse model, we elucidated the impact of cGAS-STING signaling in DCs on the activation of IL-17- and IFN-γ-producing T cells in psoriatic inflammation. Ablation of the Sting hampers DC activation leads to decreased numbers of IL-17-producing T cells and Th1 cells, and thus subsequently attenuates psoriatic inflammation in the IMQ-induced mouse model. Furthermore, we explored the therapeutic potential of the STING inhibitor C-176, which reduces psoriatic inflammation and enhances the anti-IL-17A therapeutic response. Our results underscore the critical role of cGAS-STING signaling in DCs in driving psoriatic inflammation and highlight a promising psoriasis treatment.

GRP78 Downregulation in Keratinocytes Promotes Skin Inflammation through the Recruitment and Activation of CCR6+ IL-17A-Producing γδ T Cells

The migration of γδ T lymphocytes toward skin lesions and their concomitant pathogenic IL-17A production play a crucial role in the pathogenesis of psoriasis. However, the regulatory mechanisms of IL-17A production by γδ T cells and their migration remain to be fully explored. Intracellular GRP78 is a molecular chaperone that regulates endoplasmic reticulum stress, whereas secretory GRP78, as a member of the resolution-associated molecular patterns, exerts immunoregulatory effects. In this study, we reported that both the intracellular GRP78 in skin lesions and secretory GRP78 in the serum were significantly decreased in patients with psoriasis. A GRP78 knockdown exacerbated imiquimod-induced skin inflammation, whereas the application of recombinant GRP78 protein or BIP inducer X (a GRP78 inducer) attenuated the dermatitis. Mechanistically, the GRP78 knockdown in keratinocytes enhanced the production of chemokines, specifically CCL20, which regulates γδ T-cell migration. Moreover, recombinant GRP78 was found to directly bind to γδ T cells to suppress its migration ability and proinflammatory capacities by downregulating the CCR6 and IL-17A expression. Collectively, our results uncovered a pivotal role of GRP78 in the pathogenesis of psoriasis, which was mainly exerted by regulating the interaction between keratinocytes and γδ T cells, and might provide a promising target for psoriasis therapy.

Coencapsulation of Immunosuppressive Drug with Anti-Inflammatory Molecule in Pickering Emulsions as an Innovative Therapeutic Approach for Inflammatory Dermatoses

Psoriasis is an inflammatory skin disease characterized by epidermal and immune dysfunctions. Although efficient, current topical treatments display adverse effects, including skin atrophy and burning sensation, leading to poor patient adherence. To overcome these downsides, pickering emulsions were formulated in which the calcitriol-containing dispersed phase was stabilized with either cyclosporin A- or tacrolimus-loaded poly(lactic-co-glycolic) acid nanoparticles. This study aimed to investigate their biological effects on lymphocytes and epidermal cells and their effectiveness in an imiquimod-induced psoriasis-like mouse model. Results showed that both emulsions significantly inhibited nuclear factor of activated T cell translocation in T lymphocytes as well as their IL-2 production, cell activation, and proliferation. In keratinocytes, inhibition of nuclear factor of activated T cell translocation decreased the production of IL-8 and TNF-α. Topical application of emulsions over skin biopsies ex vivo showed accumulation of rhodamin B-coupled poly(lactic-co-glycolic) acid nanoparticles throughout the epidermis by immunofluorescence and significantly decreased the antigen-presenting capacity of Langerhans cells in relation to a reduced expression of activation markers CD40, CD86, and HLA-DR. Using an imiquimod-induced psoriasis model in vivo, pickering emulsions significantly alleviated psoriasiform lesions potentially attributed to the decreased cutaneous expression of T-cell markers, proinflammatory cytokines, chemokines, and specific epidermal cell genes. Altogether, pickering emulsion might be a very efficient formulation for treating inflammatory dermatoses.

Posidonia oceanica (L.) Delile Is a Promising Marine Source Able to Alleviate Imiquimod-Induced Psoriatic Skin Inflammation

Psoriasis is a chronic immune-mediated inflammatory cutaneous disease characterized by elevated levels of inflammatory cytokines and adipokine Lipocalin-2 (LCN-2). Recently, natural plant-based products have been studied as new antipsoriatic compounds. We investigate the ability of a leaf extract of the marine plant Posidonia oceanica (POE) to inhibit psoriatic dermatitis in C57BL/6 mice treated with Imiquimod (IMQ). One group of mice was topically treated with IMQ (IMQ mice) for 5 days, and a second group received POE orally before each topical IMQ treatment (IMQ-POE mice). Psoriasis Area Severity Index (PASI) score, thickness, and temperature of the skin area treated with IMQ were measured in both groups. Upon sacrifice, the organs were weighed, and skin biopsies and blood samples were collected. Plasma and lesional skin protein expression of IL-17, IL-23, IFN-γ, IL-2, and TNF-α and plasma LCN-2 concentration were evaluated by ELISA. PASI score, thickness, and temperature of lesional skin were reduced in IMQ-POE mice, as were histological features of psoriatic dermatitis and expression of inflammatory cytokines and LCN-2 levels. This preliminary study aims to propose P. oceanica as a promising naturopathic anti-inflammatory treatment that could be introduced in Complementary Medicine for psoriasis.

Fibroblast: A Novel Target for Autoimmune and Inflammatory Skin Diseases Therapeutics

Fibroblasts are crucial components of the skin structure. They were traditionally believed to maintain the skin's structure by producing extracellular matrix and other elements. Recent research illuminated that fibroblasts can respond to external stimuli and exhibit diverse functions, such as the secretion of pro-inflammatory factors, adipogenesis, and antigen presentation, exhibiting remarkable heterogeneity and plasticity. This revelation positions fibroblasts as active contributors to the pathogenesis of skin diseases, challenging the traditional perspective that views fibroblasts solely as structural entities. Based on their diverse functions, fibroblasts can be categorized into six subtypes: pro-inflammatory fibroblasts, myofibroblasts, adipogenic fibroblasts, angiogenic fibroblasts, mesenchymal fibroblasts, and antigen-presenting fibroblasts. Cytokines, metabolism, and epigenetics regulate functional abnormalities in fibroblasts. The dynamic changes fibroblasts exhibit in different diseases and disease states warrant a comprehensive discussion. We focus on dermal fibroblasts' aberrant manifestations and pivotal roles in inflammatory and autoimmune skin diseases, including psoriasis, vitiligo, lupus erythematosus, scleroderma, and atopic dermatitis, and propose targeting aberrantly activated fibroblasts as a potential therapeutic strategy for inflammatory and autoimmune skin diseases.

NOS2-derived low levels of NO drive psoriasis pathogenesis

Psoriasis is an IL-23/Th17-mediated skin disorder with a strong genetic predisposition. The impact of its susceptibility gene nitric oxide synthase 2 (NOS2) remains unknown. Here, we demonstrate strong NOS2 mRNA expression in psoriatic epidermis, an effect that is IL-17 dependent. However, its complete translation to protein is prevented by the IL-17-induced miR-31 implying marginally upregulated NO levels in psoriatic skin. We demonstrate that lower levels of NO, as opposed to higher levels, increase keratinocyte proliferation and mediate IL-17 downstream effects. We hypothesized that the psoriatic phenotype may be alleviated by either eliminating or increasing cellular NO levels. In fact, using the imiquimod psoriasis mouse model, we found a profound impact on the psoriatic inflammation in both IMQ-treated NOS2 KO mice and wild-type mice treated with IMQ and the NO-releasing berdazimer gel. In conclusion, we demonstrate that IL-17 induces NOS2 and fine-tunes its translation towards a window of proinflammatory and hyperproliferative effects and identify NO donor therapy as a new treatment modality for psoriasis.

Shikonin-loaded PLGA nanoparticles: A promising strategy for psoriasis treatment

Psoriasis is an inflammation-based skin illness marked by aggravated proliferation of epidermal cells. Shikonin is a natural naphthoquinone obtained from Arnebiae radix. It exerts anti-inflammatory and immunosuppressive effects. However, the poor water solubility and low bioavailability of shikonin limit its application. In this study, shikosin-loaded PLGA nanoparticle hydrogel was prepared and used to deliver the drug to the epidermis of psoriasis mice through local administration. The results demonstrated that shikosin-loaded PLGA nanoparticles inhibited HaCaT cell multiplication, increased drug uptake, and induced apoptosis of HaCaT cells. Results from Western blotting assays indicated that shikosin down-regulated the protein expressions of p65 and p-p65. Furthermore, shikonin mitigated psoriasis and decreased the concentrations of inflammation-inducing cytokines, i.e., IL17A, IL-17F, IL-22, IL-1β, and TNF-α. Taken together, these results suggest that shikonin-PLGA nanoparticles loaded in hydrogel system possess promising therapeutic potential for psoriasis.

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.

Orientin alleviates the inflammatory response in psoriasis like dermatitis in BALB/c mice by inhibiting the MAPK signaling pathway

BACKGROUND

Psoriasis, a chronic inflammatory condition of the skin, is characterized by an atypical proliferation of epidermal keratinocytes and immune cell infiltration. Orientin is a flavonoid monomer with potent anti-inflammatory activities. However, the therapeutic effects of orientin on psoriasis and the underlying mechanisms have not been elucidated.

OBJECTIVE

To investigate the therapeutic effect of orientin on psoriasis and the underlying mechanisms using network pharmacology and experimental studies.

METHODS

A psoriasis-like mouse model was established using imiquimod (IMQ). Lipopolysaccharide (LPS) was used to stimulate the RAW264.7 and HaCaT cells in vitro. The therapeutic effects of orientin and the underlying mechanism were analyzed using histopathological, immunohistochemical, quantitative real-time polymerase chain reaction, enzyme-linked immunosorbent assay, flow cytometry, and western blotting analyses.

RESULTS

Orientin ameliorated skin lesions and suppressed keratinocyte proliferation and immune cell infiltration in the IMQ-induced psoriasis-like mouse model. Additionally, orientin inhibited the secretion of the pro-inflammatory factors interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, IL-8, IL-17, and IL-23 in the psoriasis-like mouse model and LPS-induced RAW264.7 and HaCaT cells. Furthermore, orientin mitigated the LPS-induced upregulation of reactive oxygen species and downregulation of IL-10 and glutathione levels. Orientin alleviated inflammation by downregulating the MAPK signaling pathway.

CONCLUSION

Orientin alleviated psoriasis-like dermatitis by suppressing the MAPK signaling pathway, suggesting that orientin is a potential therapeutic for psoriasis.

Targeting T cell plasticity in kidney and gut inflammation by pooled single-cell CRISPR screening

Pro-inflammatory CD4+ T cells are major drivers of autoimmune diseases, yet therapies modulating T cell phenotypes to promote an anti-inflammatory state are lacking. Here, we identify T helper 17 (TH17) cell plasticity in the kidneys of patients with antineutrophil cytoplasmic antibody-associated glomerulonephritis on the basis of single-cell (sc) T cell receptor analysis and scRNA velocity. To uncover molecules driving T cell polarization and plasticity, we established an in vivo pooled scCRISPR droplet sequencing (iCROP-seq) screen and applied it to mouse models of glomerulonephritis and colitis. CRISPR-based gene targeting in TH17 cells could be ranked according to the resulting transcriptional perturbations, and polarization biases into T helper 1 (TH1) and regulatory T cells could be quantified. Furthermore, we show that iCROP-seq can facilitate the identification of therapeutic targets by efficient functional stratification of genes and pathways in a disease- and tissue-specific manner. These findings uncover TH17 to TH1 cell plasticity in the human kidney in the context of renal autoimmunity.

Granzyme K mediates IL-23-dependent inflammation and keratinocyte proliferation in psoriasis

Psoriasis is an inflammatory disease with systemic manifestations that most commonly presents as itchy, erythematous, scaly plaques on extensor surfaces. Activation of the IL-23/IL-17 pro-inflammatory signaling pathway is a hallmark of psoriasis and its inhibition is key to clinical management. Granzyme K (GzmK) is an immune cell-secreted serine protease elevated in inflammatory and proliferative skin conditions. In the present study, human psoriasis lesions exhibited elevated GzmK levels compared to non-lesional psoriasis and healthy control skin. In an established murine model of imiquimod (IMQ)-induced psoriasis, genetic loss of GzmK significantly reduced disease severity, as determined by delayed plaque formation, decreased erythema and desquamation, reduced epidermal thickness, and inflammatory infiltrate. Molecular characterization in vitro revealed that GzmK contributed to macrophage secretion of IL-23 as well as PAR-1-dependent keratinocyte proliferation. These findings demonstrate that GzmK enhances IL-23-driven inflammation as well as keratinocyte proliferation to exacerbate psoriasis severity.

Calcipotriol Nanosuspension-Loaded Trilayer Dissolving Microneedle Patches for the Treatment of Psoriasis: In Vitro Delivery and In Vivo Antipsoriatic Activity Studies

Psoriasis, affecting 2-3% of the global population, is a chronic inflammatory skin condition without a definitive cure. Current treatments focus on managing symptoms. Recognizing the need for innovative drug delivery methods to enhance patient adherence, this study explores a new approach using calcipotriol monohydrate (CPM), a primary topical treatment for psoriasis. Despite its effectiveness, CPM's therapeutic potential is often limited by factors like the greasiness of topical applications, poor skin permeability, low skin retention, and lack of controlled delivery. To overcome these challenges, the study introduces CPM in the form of nanosuspensions (NSs), characterized by an average particle size of 211 ± 2 nm. These CPM NSs are then incorporated into a trilayer dissolving microneedle patch (MAP) made from poly(vinylpyrrolidone) and w poly(vinyl alcohol) as needle arrays and prefrom 3D printed polylactic acid backing layer. This MAP features rapidly dissolving tips and exhibits good mechanical properties and insertion capability with delivery efficiency compared to the conventional Daivonex ointment. The effectiveness of this novel MAP was tested on Sprague-Dawley rats with imiquimod-induced psoriasis, demonstrating efficacy comparable to the marketed ointment. This innovative trilayer dissolving MAP represents a promising new local delivery system for calcipotriol, potentially revolutionizing psoriasis treatment by enhancing drug delivery and patient compliance.

Interferon-Alpha Induces Psoriatic Inflammation in Mice by Phosphorylating FOXO3

Psoriasis is a chronic, immune-mediated inflammatory skin disease characterized by epidermal thickening and inflammatory cell infiltration. Excessive proliferation of keratinocytes and resistance to apoptosis lead to thickening of the epidermis. Plasmacytoid dendritic cells are involved in the occurrence of psoriasis mainly by secreting interferon-alpha (IFN-α). IFN-α is a glycoprotein with antiviral, antitumor, and immunomodulatory effects, but its role in psoriasis remains unclear. In this investigation, a mild psoriatic phenotype was observed in mice upon topical application of IFN-α cream, and the inflammation was exacerbated when combined with imiquimod (IMQ). Immunohistochemical analyses demonstrated that IFN-α induces psoriatic inflammation in mice by stimulating phosphorylation of forkhead box O3, consistent with the involvement of this protein in cell proliferation, apoptosis, and inflammation. Our results suggested that topical IFN-α caused psoriatic inflammation and that the psoriatic inflammation was exacerbated by the combination of IFN-α and IMQ, possibly due to the dysfunction of forkhead box O3.

Anti-psoriasis effect of 18β-glycyrrhetinic acid by breaking CCL20/CCR6 axis through its vital active group targeting GUSB/ATF2 signaling

BACKGROUND

Psoriasis is an immune-mediated chronic inflammatory skin disease. Current research suggests that the long-term persistence and recurrence of psoriasis are closely related to the feedback loop formed between keratinocytes and immune cells, especially in Th 17 or DC cells expressing CCR6. CCL20 is the ligand of CCR6. Therefore, drugs that block the expression of CCL20 or CCR6 may have a certain therapeutic effect on psoriasis. Glycyrrhetinic acid (GA) is the main active ingredient of the plant drug licorice and is often used to treat autoimmune diseases, including psoriasis. However, its mechanism of action is still unclear.

METHODS

Psoriasis like skin lesion model was established by continuously applying imiquimod on the back skin of normal mice and CCR6-/- mice for 7 days. The therapeutic and preventive effects of glycyrrhetinic acid (GA) on the model were observed and compared. The severity of skin injury is estimated through clinical PASI scores and histopathological examination. qRT-PCR and multiple cytoline assay were explored to detect the expression levels of cytokines in animal dorsal skin lesions and keratinocyte line HaCaT cells, respectively. The dermis and epidermis of the mouse back were separated for the detection of CCL20 expression. Transcription factor assay was applied to screen, and luciferase activity assay to validate transcription factors regulated by GA. Technology of surface plasmon laser resonance with LC-MS (SPR-MS), molecular docking, and enzyme activity assay were used to identified the target proteins for GA. Finally, we synthesized different derivatives of 18beta-GA and compared their effects, as well as glycyrrhetinic acid (GL), on the skin lesion of imiquimod-induced mice to evaluate the active groups of 18beta-GA.

RESULTS

18β-glycyrrhetinic acid (GA) improved IMQ-induced psoriatic lesions, and could specifically reduce the chemokine CCL20 level of the epidermis in lesion area, especially in therapeutic administration manner. The process was mainly regulated by transcription factor ATF2 in the keratinocytes. In addition, GUSB was identified as the primary target of 18βGA. Our findings indicated that the subject on molecular target research of glycyrrhizin should be glycyrrhetinic acid (GA) instead of glycyrrhizic acid (GL), because GL showed little activity in vitro or in vivo. Apart from that, α, β, -unsaturated carbonyl in C11/12 positions was crucial or unchangeable to its activity of 18βGA, while proper modification of C3 or C30 position of 18βGA may vastly increase its activity.

CONCLUSION

Our research indicates that 18βGA exerted its anti-psoriasis effect mainly by suppressing ATF2 and downstream molecule CCL20 predominately through α, β, -unsaturated carbonyl at C11/12 position binding to GUSB in the keratinocytes, and then broke the feedback loop between keratinocytes and CCR6-expressing immune cells. GA has more advantages than GL in the external treatment of psoriasis. A highlight of this study is to investigate the influence of special active groups on the pharmacological action of a natural product, inspired by the molecular docking result.