A Critical Role of the IL-1β-IL-1R Signaling Pathway in Skin Inflammation and Psoriasis Pathogenesis

GPR97 depletion aggravates imiquimod-induced psoriasis pathogenesis via amplifying IL-23/IL-17 axis signal pathway

Skin psoriasis is defined as receiving external stimulation to activate skin dendritic cells (DCs) which can release interleukin 23 (IL-23) to interlink the innate and adaptive immunity as well as induce T helper 17 (Th17) cell differentiation leading to elevated production of interleukin 17 (IL-17) for keratinocytes over production. This autoimmune loop in psoriasis pathogenesis is influenced by G protein-coupled receptor (GPCR) signalling transduction, and in particular, function of adhesion molecule GPR97 in psoriasis endures to be utterly addressed. In this research, our team allocated GPR97 depletion (GPR97-/-), GPR97 conditional depletion on dendritic cell (DC-cKO), and keratin 14-conditional knockout (K14-cKO) mice models to explore the function of GPR97 which influences keratinocytes and skin immunity. It was found that significantly aggravated psoriasis-like lesion in GPR97-/- mice. In addition, hyperproliferative keratinocytes as well as accumulation of DCs and Th17 cells were detected in imiquimod (IMQ)-induced GPR97-/- mice, which was consistent with the results in DC-cKO and K14-cKO psoriasis model. Additional investigations indicated that beclomethasone dipropionate (BDP), an agonist of GPR97, attenuated the psoriasis-like skin disease and restricted HaCaT cells abnormal proliferation as well as Th17 cells differentiation. Particularly, we found that level of NF-κB p65 was increased in GPR97-/- DCs and BDP could inhibit p65 activation in DCs. Role of GPR97 is indispensable and this adhesion receptor may affect immune cell enrichment and function in skin and alter keratinocytes proliferation as well as differentiation in psoriasis.

Commensal microbe regulation of skin cells in disease

Human skin is the host to various commensal microbes that constitute a substantial microbial community. The reciprocal communication between these microbial inhabitants and host cells upholds both the morphological and functional attributes of the skin layers, contributing indispensably to microenvironmental and tissue homeostasis. Thus, disruption of the skin barrier or imbalances in the microbial communities can exert profound effects on the behavior of host cells. This influence, mediated by the microbes themselves or their metabolites, manifests in diverse outcomes. In this review, we examine existing knowledge to provide insight into the nuanced behavior exhibited by the microbiota on skin cells in health and disease states. These interactions provide insight into potential cellular targets for future microbiota-based therapies to prevent and treat skin disease.

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.

Exploring the Therapeutic Potential of Natural Compounds in Psoriasis and Their Inclusion in Nanotechnological Systems

Psoriasis is a chronic inflammatory disease that affects around 2-3% of the world's population. The treatment for this autoimmune disease still remains centered around conventional methods using synthetic substances, even though more recent advancements focus on biological therapies. Given the numerous side effects of such treatments, current research involves plant extracts and constituents that could prove useful in treating psoriasis. The aim of this narrative review is to highlight the most known representatives belonging to classes of natural compounds such as polyphenols (e.g., astilbin, curcumin, hesperidin, luteolin, proanthocyanidins, and resveratrol), alkaloids (e.g., berberine, capsaicin, and colchicine), coumarins (psoralen and 8-methoxypsoralen), and terpenoids (e.g., celastrol, centelloids, and ursolic acid), along with plants used in traditional medicine that could present therapeutic potential in psoriasis. The paper also provides an overview of these compounds' mechanisms of action and current inclusion in clinical studies, as well as an investigation into their potential incorporation in various nanotechnological systems, such as lipid-based nanocarriers or polymeric nanomaterials, that may optimize their efficacy during treatment.

Three-dimensional genome architecture persists in a 52,000-year-old woolly mammoth skin sample

Analyses of ancient DNA typically involve sequencing the surviving short oligonucleotides and aligning to genome assemblies from related, modern species. Here, we report that skin from a female woolly mammoth (†Mammuthus primigenius) that died 52,000 years ago retained its ancient genome architecture. We use PaleoHi-C to map chromatin contacts and assemble its genome, yielding 28 chromosome-length scaffolds. Chromosome territories, compartments, loops, Barr bodies, and inactive X chromosome (Xi) superdomains persist. The active and inactive genome compartments in mammoth skin more closely resemble Asian elephant skin than other elephant tissues. Our analyses uncover new biology. Differences in compartmentalization reveal genes whose transcription was potentially altered in mammoths vs. elephants. Mammoth Xi has a tetradic architecture, not bipartite like human and mouse. We hypothesize that, shortly after this mammoth's death, the sample spontaneously freeze-dried in the Siberian cold, leading to a glass transition that preserved subfossils of ancient chromosomes at nanometer scale.

A Novel Human Interleukin-23A Overexpressing Mouse Model of Systemic Lupus Erythematosus

OBJECTIVE

Interleukin-23 (IL-23) is a crucial cytokine implicated in chronic inflammation and autoimmunity, associated with various diseases such as psoriasis, psoriatic arthritis, and systemic lupus erythematosus (SLE). This study aimed to create and characterize a transgenic mouse model overexpressing human IL-23A (TghIL-23A), providing a valuable tool for investigating the pathogenic role of human IL-23A and evaluating the efficacy of anti-human IL-23A therapeutics.

METHODS

TghIL-23A mice were generated via microinjection of CBA × C57BL/6 zygotes with a fragment of the human IL23A gene, flanked by its 5'-regulatory sequences and the 3' untranslated region of human β-globin. The TghIL-23A pathology was assessed through hematologic and biochemic analyses, cytokine and antinuclear antibody detection, and histopathologic examination of skin and renal tissues. The response to the anti-human IL-23A therapeutic agent guselkumab was evaluated in groups of eight mixed-sex mice receiving subcutaneous treatment twice weekly for 10 weeks using clinical, biomarker, and histopathologic readouts.

RESULTS

TghIL-23A mice exhibited interactions between human IL-23A and mouse IL-23/IL-12p40 and developed a chronic multiorgan autoimmune disease marked by proteinuria, anti-double-stranded DNA antibodies, severe inflammatory lesions in the skin, and milder phenotypes in the kidneys and lungs. The TghIL-23A pathologic features exhibited significant similarities to those observed in human patients with SLE, and they were reversed following guselkumab treatment.

CONCLUSION

We have generated and characterized a novel genetic mouse model of SLE, providing proof-of-concept for the etiopathogenic role of human IL-23A. This new model has a normal life span and integrates several characteristics of the human disease's complexity and chronicity, making it an attractive preclinical tool for studying IL-23-dependent pathogenic mechanisms and assessing the efficacy of anti-human IL-23A or modeled disease-related therapeutics.

Cytokines in psoriasis: From pathogenesis to targeted therapy

Psoriasis is a multifactorial disease that affects 0.84% of the global population and it can be associated with disabling comorbidities. As patients present with thick scaly lesions, psoriasis was long believed to be a disorder of keratinocytes. Psoriasis is now understood to be the outcome of the interaction between immunological and environmental factors in individuals with genetic predisposition. While it was initially thought to be solely mediated by cytokines of type-1 immunity, namely interferon-γ, interleukin-2, and interleukin-12 because it responds very well to cyclosporine, a reversible IL-2 inhibitor; the discovery of Th-17 cells advanced the understanding of the disease and helped the development of biological therapy. This article aims to provide a comprehensive review of the role of cytokines in psoriasis, highlighting areas of controversy and identifying the connection between cytokine imbalance and disease manifestations. It also presents the approved targeted treatments for psoriasis and those currently under investigation.

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.

IL-26 Potentiates Type 2 Skin Inflammation in the Presence of IL-1β

Atopic dermatitis (AD) is a debilitating inflammatory skin disorder. Biologics targeting the IL-4/IL-13 axis are effective in AD, but there is still a large proportion of patients who do not respond to IL-4R blockade. Further exploration of potentially pathogenic T-cell-derived cytokines in AD may lead to new effective treatments. This study aimed to investigate the downstream effects of IL-26 on skin in the context of type 2 skin inflammation. We found that IL-26 alone exhibited limited inflammatory activity in the skin. However, in the presence of IL-1β, IL-26 potentiated the secretion of TSLP, CXCL1, and CCL20 from human epidermis through Jak/signal transducer and activator of transcription signaling. Moreover, in an in vivo AD-like skin inflammation model, IL-26 exacerbated skin pathology and locally increased type 2 cytokines, most notably of IL13 in skin T helper cells. Neutralization of IL-1β abrogated IL-26-mediated effects, indicating that the presence of IL-1β is required for full IL-26 downstream action in vivo. These findings suggest that the presence of IL-1β enables IL-26 to be a key amplifier of inflammation in the skin. As such, IL-26 may contribute to the development and pathogenesis of inflammatory skin disorders such as AD.

Targeting the NLRP3 inflammasome in psoriasis

The NLRP3 inflammasome, a complex consisting of the nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing protein 3, has emerged as a critical mediator of pathological inflammation and a significant therapeutic target for various inflammatory diseases. Psoriasis, a chronic inflammatory skin condition without a definitive cure, has shown promising results in animal models through the inhibition of the NLRP3 inflammasome. This review aims to explore the development of the NLRP3 inflammasome in psoriasis and the molecular mechanisms responsible for its inhibition by natural products and small molecules currently being developed for psoriasis treatment. Furthermore, we are examining clinical trials using agents that block the NLRP3 pathway for the treatment of psoriasis. This study is timely to provide a new perspective on managing psoriasis.

Air pollution and skin diseases: A comprehensive evaluation of the associated mechanism

Air pollutants deteriorate the survival environment and endanger human health around the world. A large number of studies have confirmed that air pollution jeopardizes multiple organs, such as the cardiovascular, respiratory, and central nervous systems. Skin is the largest organ and the first barrier that protects us from the outside world. Air pollutants such as particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) will affect the structure and function of the skin and bring about the development of inflammatory skin diseases (atopic dermatitis (AD), psoriasis), skin accessory diseases (acne, alopecia), auto-immune skin diseases (cutaneous lupus erythematosus(CLE) scleroderma), and even skin tumors (melanoma, basal cell carcinoma (BCC), squamous-cell carcinoma (SCC)). Oxidative stress, skin barrier damage, microbiome dysbiosis, and skin inflammation are the pathogenesis of air pollution stimulation. In this review, we summarize the current evidence on the effects of air pollution on skin diseases and possible mechanisms to provide strategies for future research.

Photodegradation enhances the toxic effect of anthracene on skin

Anthracene, a polycyclic aromatic hydrocarbon (PAH), is a widespread environmental pollutant that poses potential risks to human health. Exposure to anthracene can result in various adverse health effects, including skin-related disorders. Photo exposure sufficiently removes the anthracene from the environment but also generates more degradation products which can be more toxic. The goal of this study was to assess the change in anthracene dermotoxicity caused by photodegradation and understand the mechanism of this change. In the present study, over 99.99% of anthracene was degraded within 24 h of sunlight exposure, while producing many intermediate products including 9,10-anthraquinone and phthalic acid. The anthracene products with different durations of photo exposure were applied to 2D and 3D human keratinocyte cultures. Although the non-degraded anthracene significantly delayed the cell migration, the cell viability and differentiation decreased dramatically in the presence of the photodegraded anthracene. Anthracene photodegradation products also altered the expression patterns of a number of inflammation-related genes in comparison to the control cells. Among these genes, il1a, il1b, il8, cxcl2, s100a9, and mmp1 were upregulated whereas the tlr4 and mmp3 were downregulated by the photodegraded anthracene. Topical deliveries of the photodegraded and non-degraded anthracene to the dorsal skin of hairless mice showed more toxic effects by the photodegraded anthracene. The 4-hour photodegradation products of anthracene thickened the epidermal layer, increased the dermal cellularity, and induced the upregulation of inflammatory markers, il1a, il1b, s100a9, and mmp1. In addition, it also prevented the production of a gap junction protein, Connexin-43. All the evidence suggested that photodegradation enhanced the toxicities of anthracene to the skin. The 4-hour photodegradation products of anthracene led to clinical signs similar to acute inflammatory skin diseases, such as atopic and contact dermatitis, eczema, and psoriasis. Therefore, the potential risk of skin irritation by anthracene should be also considered when an individual is exposed to PAHs, especially in environments with strong sunlight.

Crocetin preconditioning attenuates ischemia reperfusion-induced hepatic injury by disrupting Keap1/Nrf2 interaction and activating Nrf2/HO-1 pathway

BACKGROUND

Ischemia reperfusion (I/R) injury is a frequent occurrence during liver transplantation surgery, resulting from the temporary cessation of blood flow and subsequent restoration of blood flow. Serious I/R injury is a significant factor causing transplant failure. Hepatic I/R process is characterized by excessive inflammation, oxidation, and apoptosis. Crocetin (Crt) is a natural compound exhibiting beneficial roles in various I/R-induced organ damages. However, Crt's potential role in hepatic I/R remains unexplored.

OBJECTIVE AND METHODS

In order to reveal the impact of Crt on hepatic I/R and the associated signaling pathway, we utilized a syngeneic orthotopic liver transplantation rat model to induce hepatic I/R injury.

RESULTS

Pretreatment with Crt significantly mitigated hepatic I/R injury. This was evident by decreased activities of serum ALT, AST and LDH, indicating improved liver function. Crt treatment also alleviated oxidative stress, as demonstrated by decreased serum MDA content and elevated serum SOD and GSH-Px activities. Furthermore, Crt suppressed inflammatory responses by downregulating both the serum and liver IL-1β, IL-6 and TNF-α while upregulating IL-10 expression. Additionally, Crt reduced apoptosis by decreasing pro-apoptotic Bax, cleaved caspase-3 and cleaved caspase-9, while increasing anti-apoptotic Bcl2 expression. Notably, these protective effects of Crt were dose-dependent. Moreover, our data indicates that Crt plays protective functions during hepatic I/R via disrupting Keap1/Nrf2 interaction and activating Nrf2/HO-1 signaling. This was further supported by observations of alleviated hepatic histopathological changes in I/R rats treated with Crt.

CONCLUSIONS

Crt shows potential as a therapeutic agent for preventing hepatic I/R injury during clinical liver transplantation.

Biologics as a novel treatment option for palmoplantar pustulosis: a comprehensive review

Introduction

Palmoplantar pustulosis (PPP) is a complex inflammatory skin disease. Currently, no standardized treatments exist, and traditional systemic therapies often display limited effectiveness and substantial adverse effects. Biologics, however, have shown potential for enhanced clinical outcomes in psoriasis patients, thereby prompting this investigation into their applicability in PPP treatment.

Aim

This study constitutes the first comprehensive review to assess the effectiveness and underlying mechanisms of biologics for PPP.

Material and methods

We conducted a PubMed search to identify studies on biologics for PPP from 1992 onward. The review focused on assessing the efficacy of biologics targeting cytokines like IL-1, IL-8, IL-17, IL-12/23, IL-36, and TNF-α.

Results

Biologics for PPP are generally less effective than for psoriasis. Secukinumab and guselkumab, IL-17 and IL-23 inhibitors respectively, have shown better results compared to other biologics in trials. However, the effectiveness of other biologics remains uncertain due to limited data.

Conclusions

More research is needed to find effective treatments for PPP, and selecting the right biologic for each patient is challenging.

Antibodies targeting the shared cytokine receptor IL-1 receptor accessory protein invoke distinct mechanisms to block all cytokine signaling

Interleukin-1 (IL-1)-family cytokines are potent modulators of inflammation, coordinating a vast array of immunological responses across innate and adaptive immune systems. Dysregulated IL-1-family cytokine signaling, however, is involved in a multitude of adverse health effects, such as chronic inflammatory conditions, autoimmune diseases, and cancer. Within the IL-1 family of cytokines, six-IL-1α, IL-1β, IL-33, IL-36α, IL-36β, and IL-36γ-require the IL-1 receptor accessory protein (IL-1RAcP) as their shared co-receptor. Common features of cytokine signaling include redundancy of signaling pathways, sharing of cytokines and receptors, pleiotropy of the cytokines themselves, and multifaceted immune responses. Accordingly, targeting multiple cytokines simultaneously is an emerging therapeutic strategy and can provide advantages over targeting a single cytokine pathway. Here, we show that two monoclonal antibodies, CAN10 and 3G5, which target IL-1RAcP for broad blockade of all associated cytokines, do so through distinct mechanisms and provide therapeutic opportunities for the treatment of inflammatory diseases.

Antiproliferative and Anti-Inflammatory Effects of the Polyphenols Phloretin and Balsacone C in a Coculture of T Cells and Psoriatic Keratinocytes

Plaque psoriasis is a chronic inflammatory skin disease causing red inflamed lesions covered by scales. Leukocytes, including dendritic cells and T cells, participate in the inflammation of the skin by producing multiple cytokines, thus contributing to the hyperproliferation of keratinocytes. Lack of effectiveness and toxic side effects are the main concerns with conventional treatments, and research involving new antipsoriatic molecules is essential. In this study, the anti-inflammatory and antiproliferative effects of two natural polyphenols, phloretin and balsacone C, were investigated using the coculture of T cells and psoriatic keratinocytes. Phloretin exerted antiproliferative activity by regulating the expression of antigen Ki67 and proliferating cell nuclear antigen (PCNA). These effects were comparable to those of methotrexate, a reference treatment for moderate to severe psoriasis. With balsacone C, the expression of Ki67 was also reduced. Additionally, phloretin decreased the levels of multiple pro-inflammatory cytokines: monocyte chemoattractant protein-1 (MCP-1/CCL2), macrophage inflammatory protein-1α (MIP-1α), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-1 alpha (IL-1α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-17A (IL-17A), and tumor necrosis factor alpha (TNF-α). The increased interleukin-2 (IL-2) levels with phloretin and methotrexate also represented anti-inflammatory activity. Balsacone C and methotrexate decreased the levels of IL-1α and IL-1β, but methotrexate exerted a higher reduction. In summary, the anti-inflammatory effects of phloretin were more pronounced than those of methotrexate and balsacone C. In addition, the expression of lymphocyte common antigen (CD45) was more similar to that of the healthy condition after using phloretin or methotrexate. Finally, phloretin stood out from the other compounds and appears promising for psoriasis treatment.

Review: A Contemporary, Multifaced Insight into Psoriasis Pathogenesis

Psoriasis is a chronic recurrent inflammatory autoimmune pathology with a significant genetic component and several interferences of immunological cells and their cytokines. The complex orchestration of psoriasis pathogenesis is related to the synergic effect of immune cells, polygenic alterations, autoantigens, and several other external factors. The major act of the IL-23/IL-17 axis, strongly influencing the inflammatory pattern established during the disease activity, is visible as a continuous perpetuation of the pro-inflammatory response and keratinocyte activation and proliferation, leading to the development of psoriatic lesions. Genome-wide association studies (GWASs) offer a better view of psoriasis pathogenic pathways, with approximately one-third of psoriasis's genetic impact on psoriasis development associated with the MHC region, with genetic loci located on chromosome 6. The most eloquent genetic factor of psoriasis, PSORS1, was identified in the MHC I site. Among the several factors involved in its complex etiology, dysbiosis, due to genetic or external stimulus, induces a burst of pro-inflammatory consequences; both the cutaneous and gut microbiome get involved in the psoriasis pathogenic process. Cutting-edge research studies and comprehensive insights into psoriasis pathogenesis, fostering novel genetic, epigenetic, and immunological factors, have generated a spectacular improvement over the past decades, securing the path toward a specific and targeted immunotherapeutic approach and delayed progression to inflammatory arthritis. This review aimed to offer insight into various domains that underline the pathogenesis of psoriasis and how they influence disease development and evolution. The pathogenesis mechanism of psoriasis is multifaceted and involves an interplay of cellular and humoral immunity, which affects susceptible microbiota and the genetic background. An in-depth understanding of the role of pathogenic factors forms the basis for developing novel and individualized therapeutic targets that can improve disease management.

Mass Spectrometry-Based Proteomics Analysis Unveils PTPRS Inhibits Proliferation and Inflammatory Response of Keratinocytes in Psoriasis

In this study, we used data-independent acquisition-mass spectrometry (DIA-MS) to analyze the serum proteome in psoriasis vulgaris (PsO). The serum proteomes of seven healthy controls and eight patients with PsO were analyzed using DIA-MS. Weighted gene co-expression network analysis was used to identify differentially expressed proteins (DEPs) that were closely related to PsO. Hub proteins of PsO were also identified. The Proteomics Drug Atlas 2023 was used to predict candidate hub protein drugs. To confirm the expression of the candidate factor, protein tyrosine phosphatase receptor S (PTPRS), in psoriatic lesions and the psoriatic keratinocyte model, immunohistochemical staining, quantitative real-time polymerase chain reaction, and western blotting were performed. A total of 129 DEPs were found to be closely related to PsO. The hub proteins for PsO were PVRL1, FGFR1, PTPRS, CDH2, CDH1, MCAM, and THY1. Five candidate hub protein drugs were identified: encorafenib, leupeptin, fedratinib, UNC 0631, and SCH 530348. PTPRS was identified as a common pharmacological target for these five drugs. PTPRS knockdown in keratinocytes promoted the proliferation and expression of IL-1α, IL-1β, IL-23A, TNF-α, MMP9, CXCL8, and S100A9. PTPRS expression was decreased in PsO, and PTPRS negatively regulated PsO. PTPRS may be involved in PsO pathogenesis through the inhibition of keratinocyte proliferation and inflammatory responses and is a potential treatment target for PsO.

Case report: Regression of in-transit metastases of cutaneous squamous cell carcinoma with combination pembrolizumab and topical diphencyprone

While typically low-risk, cutaneous squamous cell carcinoma (cSCC) can infrequently progress to metastatic disease with in-transit lesions, localized to the dermis or subcutaneous tissue between the primary tumor and draining regional lymph nodes. These lesions are associated with poor prognostic values, including decreased survival rates and increased risk of recurrence. We present the case of a 75-year-old male with cSCC and in-transit metastases on his scalp treated with the immune checkpoint inhibitor (ICI) pembrolizumab in conjunction with diphencyprone (DPCP), a topical hapten that induces a delayed-type hypersensitivity reaction in the skin. The patient was enrolled in a clinical trial (NCT05481658) that involved the twice-weekly application of DPCP 0.04% ointment to four of the in-transit metastases on his frontal scalp, concurrent with pembrolizumab 300 mg administered every three weeks. Following effective sensitization and a twelve-week treatment course, complete clearance of all lesions, DPCP-treated and non-DPCP treated, was achieved, with no adverse events. The immunologic profiles of the post-treatment biopsies were analyzed by TaqMan Low Density Array quantitative real-time polymerase chain reaction to measure immune marker gene expression. Relative to the non-DPCP-treated lesion, the DPCP-treated lesion demonstrated increased pro-inflammatory genetic markers and T-cell activation. This case represents the first reported instance of in-transit metastases of cSCC successfully treated with DPCP and an ICI. It highlights the potential safety and efficacy of DPCP with systemic immunotherapy for the management of in-transit metastases of cSCC in patients for whom surgery and radiation may be contraindicated.

Impaired autophagy in myeloid cells aggravates psoriasis-like skin inflammation through the IL-1β/CXCL2/neutrophil axis

BACKGROUND

Psoriasis is an inflammatory skin disease characterized by the hyperproliferative epidermal keratinocytes and significant immune cells infiltration, leading to cytokines production such as IL-1β, TNF-α, IL-23, and IL-17. Recent study highlights the critical role of IL-1β in the induction and activation of pathogenic Th17 and IL-17-producing γδ T cells, contributing to psoriasis. However, the mechanism underlying IL-1β dysregulation in psoriasis pathogenesis is unclear. Autophagy regulates IL-1β production and has a pleiotropic effect on inflammatory disorders. Previous studies showed controversial role of autophagy in psoriasis pathogenesis, either pro-inflammatory in autophagy-deficient keratinocyte or anti-inflammatory in pharmacologically autophagy-promoting macrophages. Thus, the direct role of autophagy and its therapeutic potential in psoriasis remains unclear.

METHODS

We used myeloid cell-specific autophagy-related gene 7 (Atg7)-deficient mice and determined the effect of autophagy deficiency in myeloid cells on neutrophilia and disease pathogenesis in an imiquimod-induced psoriasis mouse model. We then assessed the pathogenic mechanism focusing on immune cells producing IL-1β and IL-17 along with gene expression profiles associated with psoriasis in mouse model and public database on patients. Moreover, therapeutic potential of IL-1β blocking in such context was assessed.

RESULTS

We found that autophagy deficiency in myeloid cells exacerbated neutrophilic inflammation and disease pathogenesis in mice with psoriasis. This autophagy-dependent effect was associated with a significant increase in IL-1β production from myeloid cells, particularly macrophages, Cxcl2 expression, and IL-17 A producing T cells including γδ T cells. Supporting this, treatment with systemic IL-1 receptor blocking antibody or topical saccharin, a disaccharide suppressing pro-IL-1β expression, led to the alleviation of neutrophilia and psoriatic skin inflammation linked to autophagy deficiency. The pathophysiological relevance of this finding was supported by dysregulation of autophagy-related genes and their correlation with Th17 cytokines in psoriatic skin lesion from patients with psoriasis.

CONCLUSIONS

Our results suggest that autophagy dysfunction in myeloid cells, especially macrophages, along with IL-1β dysregulation has a causal role in neutrophilic inflammation and psoriasis pathogenesis.

Functional Genomics and Insights into the Pathogenesis and Treatment of Psoriasis

Psoriasis is a lifelong, systemic, immune mediated inflammatory skin condition, affecting 1-3% of the world's population, with an impact on quality of life similar to diseases like cancer or diabetes. Genetics are the single largest risk factor in psoriasis, with Genome-Wide Association (GWAS) studies showing that many psoriasis risk genes lie along the IL-23/Th17 axis. Potential psoriasis risk genes determined through GWAS can be annotated and characterised using functional genomics, allowing the identification of novel drug targets and the repurposing of existing drugs. This review is focused on the IL-23/Th17 axis, providing an insight into key cell types, cytokines, and intracellular signaling pathways involved. This includes examination of currently available biological treatments, time to relapse post drug withdrawal, and rates of primary/secondary drug failure, showing the need for greater understanding of the underlying genetic mechanisms of psoriasis and how they can impact treatment. This could allow for patient stratification towards the treatment most likely to reduce the burden of disease for the longest period possible.

Interleukin-1 family cytokines at the crossroads of microbiome regulation in barrier health and disease

Recent advances in understanding how the microbiome can influence both the physiology and the pathogenesis of disease in humans have highlighted the importance of gaining a deeper insight into the complexities of the host-microbial dialogue. In tandem with this progress, has been a greater understanding of the biological pathways which regulate both homeostasis and inflammation at barrier tissue sites, such as the skin and the gut. In this regard, the Interleukin-1 family of cytokines, which can be segregated into IL-1, IL-18 and IL-36 subfamilies, have emerged as important custodians of barrier health and immunity. With established roles as orchestrators of various inflammatory diseases in both the skin and intestine, it is now becoming clear that IL-1 family cytokine activity is not only directly influenced by external microbes, but can also play important roles in shaping the composition of the microbiome at barrier sites. This review explores the current knowledge surrounding the evidence that places these cytokines as key mediators at the interface between the microbiome and human health and disease at the skin and intestinal barrier tissues.

Effects on peripheral and central nervous system of key inflammatory intercellular signalling peptides and proteins in psoriasis

Psoriasis is a chronic systemic inflammatory cutaneous disease. Where the immune system plays an important role in its pathogenesis, with key inflammatory intercellular signalling peptides and proteins including IL-17 and IL-23. The psychoneurological system also figures prominently in development of psoriasis. There is a high prevalence of comorbidity between psoriasis and mental health disorders such as depression, anxiety and mania. Patients with psoriasis often suffer from pathological pain in the lesions, and their neurological accidents could improve the lesions in innervated areas. The immune system and the psychoneurological system interact closely in the pathogenesis of psoriasis. Patients with psoriasis exhibit abnormal levels of neuropeptides both in circulating and localized lesion, acting as immunomodulators involved in the inflammatory response. Moreover, receptors for inflammatory factors are expressed in both peripheral and central nervous systems (CNSs), suggesting that nervous system can receive and be influenced by signals from immune system. Key inflammatory intercellular signalling peptides and proteins in psoriasis, such as IL-17 and IL-23, can be involved in sensory signalling and may affect synaptic plasticity and the blood-brain barrier of CNS through the circulation. This review provides an overview of the multiple effects on the peripheral and CNS under conditions of systemic inflammation in psoriasis, providing a framework and inspiration for in-depth studies of neuroimmunomodulation in psoriasis.

Spatiotemporal orchestration of macrophage activation trajectories by Vγ4 T cells during skin wound healing

Dysregulated macrophage polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotypes underlies impaired cutaneous wound healing. This study reveals Vγ4+ γδ T cells spatiotemporally calibrate macrophage trajectories during skin repair via sophisticated interferon-γ (IFN-γ) conditioning across multiple interconnected tissues. Locally within wound beds, infiltrating Vγ4+ γδ T cells directly potentiate M1 activation and suppress M2 polarization thereby prolonging local inflammation. In draining lymph nodes, infiltrated Vγ4+ γδ T cells expand populations of IFN-γ-competent lymphocytes which disseminate systemically and infiltrate into wound tissues, further enforcing M1 macrophages programming. Moreover, Vγ4+γδ T cells flushed into bone marrow stimulate increased IFN-γ production, which elevates the output of pro-inflammatory Ly6C+monocytes. Mobilization of these monocytes continually replenishes the M1 macrophage pool in wounds, preventing phenotypic conversion to M2 activation. Thus, multi-axis coordination of macrophage activation trajectories by trafficking Vγ4+ γδ T cells provides a sophisticated immunological mechanism regulating inflammation timing and resolution during skin repair.

Inhibition of Mitochondrial Translation Ameliorates Imiquimod-Induced Psoriasis-Like Skin Inflammation by Targeting Vγ4+ γδ T Cells

Psoriasis is an inflammatory skin disorder that is characterized by keratinocyte hyperproliferation in response to immune cell infiltration and cytokine secretion in the dermis. γδ T cells expressing the Vγ4 TCR chain are among the highest contributors of IL-17A, which is a major cytokine that drives a psoriasis flare, making Vγ4+ γδ T cells a suitable target to restrict psoriasis progression. In this study, we demonstrate that mitochondrial translation inhibition within Vγ4+ γδ T cells effectively reduced erythema, scaling, and skin thickening in a murine model of psoriatic disease. The antibiotic linezolid, which blocks mitochondrial translation, inhibited the production of mitochondrial-encoded protein cytochrome c oxidase in Vγ4+ γδ T cells and systemically reduced the frequencies of IL-17A+ Vγ4+ γδ T cells, effectively resolving IL-17A-dependent inflammation. Inhibiting mitochondrial translation could be a novel metabolic approach to interrupt IL-17A signaling in Vγ4+ T cells and reduce psoriasis-like skin pathophysiology.

Rh family C glycoprotein contributes to psoriatic inflammation through regulating the dysdifferentiation and cytokine secretion of keratinocytes

BACKGROUND

Keratinocyte dysdifferentiation and proinflammatory cytokine production play a central role in psoriatic inflammation. According to recent studies, the Rh family C glycoprotein (RHCG) enhances cell proliferation and disrupts cell differentiation. However, the specific role of RHCG psoriasis development remains unclear.

OBJECTIVE

We here explored the effect of RHCG on keratinocytes under psoriatic inflammation.

METHODS

The cell counting kit‑8 assay was conducted to assess proliferation. RHCG protein expression was assessed through western blotting and enzyme-linked immunosorbent assays. The expression of proinflammatory cytokines and differentiation markers was analyzed through a quantitative reverse-transcription polymerase chain reaction.

RESULTS

Both RHCG mRNA and protein levels increased in psoriatic skin. Notably, cultured keratinocytes treated with an M5 cocktail, which mimics psoriatic inflammation, exhibited higher RHCG expression. Furthermore, RHCG overexpression promoted keratinocyte proliferation, accompanied by an increase in the production of interleukin (IL)-1β, IL-6, and IL-8, and tumor necrosis factor-α. RHCG overexpression also resulted in higher expression of keratin 17, a differentiation marker. Conversely, RHCG gene knockdown reduced keratinocyte proliferation and cytokine secretion. RHCG inhibition in cells recovered both keratin 1 and loricrin expression. Additionally, RHCG overexpression facilitated the phosphorylation of nuclear factor-kappa B and extracellular signal-regulated protein kinase signaling pathways. Importantly, when these signaling pathways were inhibited, the effect of RHCG on keratinocytes was attenuated.

CONCLUSION

These findings support the substantial role of RHCG in psoriatic inflammation development and suggest that RHCG serves as a potential target for psoriasis treatment.

The Immunology of Psoriasis-Current Concepts in Pathogenesis

Psoriasis is one of the most common inflammatory skin diseases with a chronic, relapsing-remitting course. The last decades of intense research uncovered a pathological network of interactions between immune cells and other types of cells in the pathogenesis of psoriasis. Emerging evidence indicates that dendritic cells, TH17 cells, and keratinocytes constitute a pathogenic triad in psoriasis. Dendritic cells produce TNF-α and IL-23 to promote T cell differentiation toward TH17 cells that produce key psoriatic cytokines IL-17, IFN-γ, and IL-22. Their activity results in skin inflammation and activation and hyperproliferation of keratinocytes. In addition, other cells and signaling pathways are implicated in the pathogenesis of psoriasis, including TH9 cells, TH22 cells, CD8+ cytotoxic cells, neutrophils, γδ T cells, and cytokines and chemokines secreted by them. New insights from high-throughput analysis of lesional skin identified novel signaling pathways and cell populations involved in the pathogenesis. These studies not only expanded our knowledge about the mechanisms of immune response and the pathogenesis of psoriasis but also resulted in a revolution in the clinical management of patients with psoriasis. Thus, understanding the mechanisms of immune response in psoriatic inflammation is crucial for further studies, the development of novel therapeutic strategies, and the clinical management of psoriasis patients. The aim of the review was to comprehensively present the dysregulation of immune response in psoriasis with an emphasis on recent findings. Here, we described the role of immune cells, including T cells, B cells, dendritic cells, neutrophils, monocytes, mast cells, and innate lymphoid cells (ILCs), as well as non-immune cells, including keratinocytes, fibroblasts, endothelial cells, and platelets in the initiation, development, and progression of psoriasis.

Single-cell sequencing analysis and multiple machine-learning models revealed the cellular crosstalk of dendritic cells and identified FABP5 and KLRB1 as novel biomarkers for psoriasis

Background

Psoriasis is an immune-mediated disorder influenced by environmental factors on a genetic basis. Despite advancements, challenges persist, including the diminishing efficacy of biologics and small-molecule targeted agents, alongside managing recurrence and psoriasis-related comorbidities. Unraveling the underlying pathogenesis and identifying valuable biomarkers remain pivotal for diagnosing and treating psoriasis.

Methods

We employed a series of bioinformatics (including single-cell sequencing data analysis and machine learning techniques) and statistical methods to integrate and analyze multi-level data. We observed the cellular changes in psoriatic skin tissues, screened the key genes Fatty acid binding protein 5 (FABP5) and The killer cell lectin-like receptor B1 (KLRB1), evaluated the efficacy of six widely prescribed drugs on psoriasis treatment in modulating the dendritic cell-associated pathway, and assessed their overall efficacy. Finally, RT-qPCR, immunohistochemistry, and immunofluorescence assays were used to validate.

Results

The regulatory influence of dendritic cells (DCs) on T cells through the CD70/CD27 signaling pathway may emerge as a significant facet of the inflammatory response in psoriasis. Notably, FABP5 and KLRB1 exhibited up-regulation and co-localization in psoriatic skin tissues and M5-induced HaCaT cells, serving as potential biomarkers influencing psoriasis development.

Conclusion

Our study analyzed the impact of DC-T cell crosstalk in psoriasis, elucidated the characterization of two biomarkers, FABP5 and KLRB1, in psoriasis, and highlighted the promise and value of tofacitinib in psoriasis therapy targeting DCs.

Scabies: Immunopathogenesis and pathological changes

Scabies is an itchy skin disease caused by the burrowing mite Sarcoptes scabiei. During their lifespan, the female mites invade the stratum corneum and create tunnels, in which they reside, move, feed, deposit fecal pellets, and lay eggs. Recently, scabies was included in the World Health Organization roadmap for neglected tropical diseases 2021-2030. This review attempts to summarize our knowledge about the mite's biology and the disease pathogenesis, pathological changes, and complications. Generally, the host-parasite interaction in scabies is highly complex and involves different mechanisms, some of which are yet largely unknown. Elucidation of the nature of such interaction as well as the underlying mechanisms could allow a better understanding of the mite's biology and the development of novel diagnostic and therapeutic options for scabies control programs. Moreover, identification of the molecular basis of such interaction could unveil novel targets for acaricidal agents and vaccines.

Inflammatory and Immunomodulatory Effects of Tripterygium wilfordii Multiglycoside in Mouse Models of Psoriasis Keratinocytes

OBJECTIVE

To determine the role of Tripterygium wilfordii multiglycoside (TGW) in the treatment of psoriatic dermatitis from a cellular immunological perspective.

METHODS

Mouse models of psoriatic dermatitis were established by imiquimod (IMQ). Twelve male BALB/c mice were assigned to IMQ or IMQ+TGW groups according to a random number table. Histopathological changes in vivo were assessed by hematoxylin and eosin staining. Ratios of immune cells and cytokines in mice, as well as PAM212 cell proliferation in vitro were assessed by flow cytometry. Pro-inflammatory cytokine expression was determined using reverse transcription quantitative polymerase chain reaction.

RESULTS

TGW significantly ameliorated the severity of IMQ-induced psoriasis-like mouse skin lesions and restrained the activation of CD45+ cells, neutrophils and T lymphocytes (all P<0.01). Moreover, TGW significantly attenuated keratinocytes (KCs) proliferation and downregulated the mRNA levels of inflammatory cytokines including interleukin (IL)-17A, IL-23, tumor necrosis factor α, and chemokine (C-X-C motif) ligand 1 (P<0.01 or P<0.05). Furthermore, it reduced the number of γ δ T17 cells in skin lesion of mice and draining lymph nodes (P<0.01).

CONCLUSIONS

TGW improved psoriasis-like inflammation by inhibiting KCs proliferation, as well as the associated immune cells and cytokine expression. It inhibited IL-17 secretion from γ δ T cells, which improved the immune-inflammatory microenvironment of psoriasis.

Interleukins and Psoriasis

Psoriasis is an immune-mediated chronic inflammatory skin disease that affects 2% to 3% of the world's population. It is widely assumed that immune cells and cytokines acting together play a crucial part in the pathophysiology of psoriasis by promoting the excessive proliferation of skin keratinocytes and inflammatory infiltration. Interleukins (ILs), as a critical component of cytokines, have been closely associated with the pathogenesis and progression of psoriasis. This review summarizes the current contribution of ILs to psoriasis and describes the role each IL performs in psoriasis. Furthermore, the paper presents the therapeutic effects and application prospects of biologics developed for ILs in clinical treatment and experiments. The study aims to further the research on ILs in the treatment of psoriasis.

Anticipation and Verification of Dendrobium-Derived Nanovesicles for Skin Wound Healing Targets, Predicated Upon Immune Infiltration and Senescence

Background

Dendrobium, with profound botanical importance, reveals a rich composition of bioactive compounds, including polysaccharides, flavonoids, alkaloids, and diverse amino acids, holding promise for skin regeneration. However, the precise mechanism remains elusive. Seeking a potent natural remedy for wound healing, exocyst vesicles were successfully isolated from Dendrobium.

Aims of the Study

This investigation aimed to employ bioinformatics and in vivo experiments to elucidate target genes of Dendrobium-derived nanovesicles in skin wound healing, focusing on immune infiltration and senescence characteristics.

Materials and Methods

C57 mice experienced facilitated wound healing through Dendrobium-derived nanovesicles (DDNVs). Bioinformatics analysis and GEO database mining identified crucial genes by intersecting immune-related, senescence-related, and PANoptosis-associated genes. The identified genes underwent in vivo validation.

Results

DDNVs remarkably accelerated skin wound healing in C57 mice. Bioinformatics analysis revealed abnormal expression patterns of immune-related, senescence-related, and pan-apoptosis-related genes, highlighting an overexpressed IL-1β and downregulated IL-18 in the model group, Exploration of signaling pathways included IL-17, NF-kappa B, NOD-like receptor, and Toll-like receptor pathways. In vivo experiments confirmed DDNVs' efficacy in suppressing IL-1β expression, enhancing wound healing.

Conclusion

Plant-derived nanovesicles (PDNV) emerged as a natural, reliable, and productive approach to wound healing. DDNVs uptake by mouse skin tissues, labeled with a fluorescent dye, led to enhanced wound healing in C57 mice. Notably, IL-1β overexpression in immune cells and genes played a key role. DDNVs intervention effectively suppressed IL-1β expression, accelerating skin wound tissue repair.

Role of the NLRP1 inflammasome in skin cancer and inflammatory skin diseases

Inflammasomes are cytoplasmic protein complexes that play a crucial role in protecting the host against pathogenic and sterile stressors by initiating inflammation. Upon activation, these complexes directly regulate the proteolytic processing and activation of proinflammatory cytokines interleukin (IL)-1β and IL-18 to induce a potent inflammatory response, and induce a programmed form of cell death called pyroptosis to expose intracellular pathogens to the surveillance of the immune system, thus perpetuating inflammation. There are various types of inflammasome complexes, with the NLRP1 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-1) inflammasome being the first one identified and currently recognized as the predominant inflammasome sensor protein in human keratinocytes. Human NLRP1 exhibits a unique domain structure, containing both an N-terminal pyrin (PYD) domain and an effector C-terminal caspase recruitment domain (CARD). It can be activated by diverse stimuli, such as viruses, ultraviolet B radiation and ribotoxic stress responses. Specific mutations in NLRP1 or related genes have been associated with rare monogenic skin disorders, such as multiple self-healing palmoplantar carcinoma; familial keratosis lichenoides chronica; autoinflammation with arthritis and dyskeratosis; and dipeptidyl peptidase 9 deficiency. Recent research breakthroughs have also highlighted the involvement of dysfunctions in the NLRP1 pathway in a handful of seemingly unrelated dermatological conditions. These range from monogenic autoinflammatory diseases to polygenic autoimmune diseases such as vitiligo, psoriasis, atopic dermatitis and skin cancer, including squamous cell carcinoma, melanoma and Kaposi sarcoma. Additionally, emerging evidence implicates NLRP1 in systemic lupus erythematosus, pemphigus vulgaris, Addison disease, Papillon-Lefèvre syndrome and leprosy. The aim of this review is to shed light on the implications of pathological dysregulation of the NLRP1 inflammasome in skin diseases and investigate the potential rationale for targeting this pathway as a future therapeutic approach.

Dynamic Boolean modeling of molecular and cellular interactions in psoriasis predicts drug target candidates

Psoriasis arises from complex interactions between keratinocytes and immune cells, leading to uncontrolled inflammation, immune hyperactivation, and a perturbed keratinocyte life cycle. Despite the availability of drugs for psoriasis management, the disease remains incurable. Treatment response variability calls for new tools and approaches to comprehend the mechanisms underlying disease development. We present a Boolean multiscale population model that captures the dynamics of cell-specific phenotypes in psoriasis, integrating discrete logical formalism and population dynamics simulations. Through simulations and network analysis, the model predictions suggest that targeting neutrophil activation in conjunction with inhibition of either prostaglandin E2 (PGE2) or STAT3 shows promise comparable to interleukin-17 (IL-17) inhibition, one of the most effective treatment options for moderate and severe cases. Our findings underscore the significance of considering complex intercellular interactions and intracellular signaling in psoriasis and highlight the importance of computational approaches in unraveling complex biological systems for drug target identification.

Triggers for the onset and recurrence of psoriasis: a review and update

Psoriasis is an immune-mediated inflammatory skin disease, involving a complex interplay between genetic and environmental factors. Previous studies have demonstrated that genetic factors play a major role in the pathogenesis of psoriasis. However, non-genetic factors are also necessary to trigger the onset and recurrence of psoriasis in genetically predisposed individuals, which include infections, microbiota dysbiosis of the skin and gut, dysregulated lipid metabolism, dysregulated sex hormones, and mental illness. Psoriasis can also be induced by other environmental triggers, such as skin trauma, unhealthy lifestyles, and medications. Understanding how these triggers play a role in the onset and recurrence of psoriasis provides insights into psoriasis pathogenesis, as well as better clinical administration. In this review, we summarize the triggers for the onset and recurrence of psoriasis and update the current evidence on the underlying mechanism of how these factors elicit the disease. Video Abstract.

Secoemestrin C Ameliorates Psoriasis-like Skin Inflammation in Mice by Suppressing the TNF-α/NF-κB Signaling Pathway

OBJECTIVE

Secoemestrin C (SC), an epitetrathiodioxopiperazine isolated from Aspergillus nidulans, has been previously reported to have immunomodulatory and hepatoprotective effects against acute autoimmune hepatitis. However, the effect of SC on regulating the inflammation and its underlying mechanisms in the pathogenesis of psoriasis remain unclear. This study aimed to evaluate the effects of SC on inflammatory dermatosis both in vitro and in vivo.

METHODS

In vitro, HaCaT cells were induced with tumor necrosis factor-alpha (TNF-α, 10 ng/mL) to establish an inflammatory injury model, and the expression of nuclear transcription factor-κB (NF-κB) pathway components was measured using qRT-PCR and Western blotting. An in vivo mouse model of imiquimod (IMQ)-induced psoriasis-like skin inflammation was used to evaluate the effectiveness of SC in alleviating psoriasis.

RESULTS

SC significantly blocked the activation of NF-κB signaling in TNF-α-stimulated HaCaT cells. In addition, systemic and local administration of SC improved psoriatic dermatitis in the IMQ-induced mouse model. SC reduced skin scale and significantly inhibited the secretion of inflammatory factors in skin lesions.

CONCLUSION

The protective effect of SC against psoriatic-associated inflammation reveals its potential therapeutic value for treating psoriasis.

Fucosylation deficiency enhances imiquimod-induced psoriasis-like skin inflammation by promoting CXCL1 expression

Psoriasis is a multifaceted chronic inflammatory skin disease; however, its underlying molecular mechanisms remain unclear. In this study, we explored the role of fucosylation in psoriasis using an imiquimod-induced psoriasis-like mouse model. ABH antigen and fucosyltransferase 1 (Fut1) expression was reduced in the granular layer of lesional skin of patients with psoriasis. In particular, the blood group H antigen type 2 (H2 antigen)-a precursor of blood group A and B antigens-and FUT1 were highly expressed throughout the spinous layer in both patients with psoriasis and the skin of imiquimod-treated mice. Upon the application of imiquimod, Fut1-deficient mice, which lacked the H2 antigen, exhibited higher clinical scores based on erythema, induration, and scaling than those of wild-type mice. Imiquimod-treated Fut1-deficient mice displayed increased skin thickness, trans-epidermal water loss, and Gr-1+ cell infiltration compared with wild-type mice. Notably, the levels of CXCL1 protein and mRNA were significantly higher in Fut1-deficient mice than those in wild-type mice; however, there were no significant differences in other psoriasis-related markers, such as IL-1β, IL-6, IL-17A, and IL-23. Fut1-deficient primary keratinocytes treated with IL-17A also showed a significant increase in both mRNA and protein levels of CXCL1 compared with IL-17A-treated wild-type primary keratinocytes. Further mechanistic studies revealed that this increased Cxcl1 mRNA in Fut1-deficient keratinocytes was caused by enhanced Cxcl1 mRNA stabilization. In summary, our findings indicated that fucosylation, which is essential for ABH antigen synthesis in humans, plays a protective role in psoriasis-like skin inflammation and is a potential therapeutic target for psoriasis.

An AhR-Ovol1-Id1 regulatory axis in keratinocytes promotes skin homeostasis against atopic dermatitis

Skin is our outer permeability and immune defense barrier against myriad external assaults. Aryl hydrocarbon receptor (AhR) senses environmental factors and regulates barrier robustness and immune homeostasis. AhR agonist is in clinical trial for atopic dermatitis (AD) treatment, but the underlying mechanism of action remains ill-defined. Here we report OVOL1/Ovol1 as a conserved and direct transcriptional target of AhR in epidermal keratinocytes. We show that OVOL1/Ovol1 impacts AhR regulation of keratinocyte gene expression, and Ovol1 deletion in keratinocytes hampers AhR's barrier promotion function and worsens AD-like inflammation. Mechanistically, we identify Ovol1's direct downstream targets genome-wide, and provide in vivo evidence for Id1's critical role in barrier maintenance and disease suppression. Furthermore, our findings reveal an IL-1/dermal γδT cell axis exacerbating both type 2 and type 3 immune responses downstream of barrier perturbation in Ovol1 -deficient AD skin. Finally, we present data suggesting the clinical relevance of OVOL1 and ID1 function in human AD. Our study highlights a keratinocyte-intrinsic AhR-Ovol1-Id1 regulatory axis that promotes both epidermal and immune homeostasis against AD-like inflammation, implicating new therapeutic targets for AD.

Single-cell analysis of psoriasis resolution demonstrates an inflammatory fibroblast state targeted by IL-23 blockade

Biologic therapies targeting the IL-23/IL-17 axis have transformed the treatment of psoriasis. However, the early mechanisms of action of these drugs remain poorly understood. Here, we perform longitudinal single-cell RNA-sequencing in affected individuals receiving IL-23 inhibitor therapy. By profiling skin at baseline, day 3 and day 14 of treatment, we demonstrate that IL-23 blockade causes marked gene expression shifts, with fibroblast and myeloid populations displaying the most extensive changes at day 3. We also identify a transient WNT5A+/IL24+ fibroblast state, which is only detectable in lesional skin. In-silico and in-vitro studies indicate that signals stemming from these WNT5A+/IL24+ fibroblasts upregulate multiple inflammatory genes in keratinocytes. Importantly, the abundance of WNT5A+/IL24+ fibroblasts is significantly reduced after treatment. This observation is validated in-silico, by deconvolution of multiple transcriptomic datasets, and experimentally, by RNA in-situ hybridization. These findings demonstrate that the evolution of inflammatory fibroblast states is a key feature of resolving psoriasis skin.

Roles of tumor necrosis factor-like ligand 1A in γδT-cell activation and psoriasis pathogenesis

Background

Interleukin (IL)-17-producing γδT (γδT17) cells mediate inflammatory responses in barrier tissues. Dysregulated γδT17 cell activation can lead to the overproduction of IL-17 and IL-22 and the development of inflammatory diseases, including psoriasis. IL-23 and IL-1β are known to synergistically activate γδT17 cells, but the regulatory mechanisms of γδT17 cells have not been fully elucidated. This study aimed to reveal the contribution of the inflammatory cytokine tumor necrosis factor-like ligand 1A (TL1A) to γδT17 cell activation and psoriasis development.

Methods

Anti-TL1A antibody was injected into an imiquimod (IMQ)-induced murine psoriasis model. TL1A receptor expression was analyzed in splenic and dermal γδT cells. γδT cells were tested for cytokine production in vitro and in vivo under stimulation with IL-23, IL-1β, and TL1A. TL1A was applied to a psoriasis model induced by intradermal IL-23 injection. Mice deficient in γδT cells were intradermally injected with IL-23 plus TL1A to verify the contribution of TL1A-dependent γδT-cell activation to psoriasis development.

Results

Neutralization of TL1A attenuated γδT17 cell activation in IMQ-treated skin. TL1A induced cytokine production by splenic γδT17 cells in synergy with IL-23. Dermal γδT17 cells constitutively expressed a TL1A receptor at high levels and vigorously produced IL-22 upon intradermal IL-23 and TL1A injection but not IL-23 alone. TL1A exacerbated the dermal symptoms induced by IL-23 injection in wild-type but not in γδT cell-deficient mice.

Conclusion

These findings suggest a novel regulatory mechanism of γδT cells through TL1A and its involvement in psoriasis pathogenesis as a possible therapeutic target.

Pustular psoriasis: A distinct aetiopathogenic and clinical entity

Pustular psoriasis is a distinct subset of psoriasis that presents with involvement of the skin in the form of sterile pustules along with systemic manifestations. Though it has been conventionally grouped under the umbrella of psoriasis, recent research has shed light on its pathogenetic mechanisms associated with the IL-36 pathway, which is distinct from conventional psoriasis. Pustular psoriasis in itself is a heterogeneous entity consisting of various subtypes, including generalised, localised, acute, and chronic forms. There is confusion regarding its current classification as entities like deficiency of IL-36 antagonist (DITRA) which are closely related to pustular psoriasis both in their pathogenetic mechanism and its clinical manifestations, are not included under pustular psoriasis. Entities like palmoplantar pustulosis, which presents with similar clinical features but is pathogenetically distinct from other forms of pustular psoriasis, are included under this condition. Management of pustular psoriasis depends upon its severity; while some of the localised variants can be managed with topical therapy alone, the generalised variants like Von Zumbusch disease and impetigo herpetiformis may need intensive care unit admission and tailor-made treatment protocols. The advent of newer biologics and better insight into the pathogenesis of pustular psoriasis has opened the way for newer therapies, including tumour necrosis factor-alpha inhibitors, interleukin-1 inhibitors, interleukin-17 inhibitors, and granulocyte monocyte apheresis. It continues to be an enigma whether pustular psoriasis is actually a variant of psoriasis or an entirely different disease entity, though we feel that it is an entirely different disease process.

Pathological and Therapeutical Implications of Pyroptosis in Psoriasis and Hidradenitis Suppurativa: A Narrative Review

This manuscript explores the role of pyroptosis, an inflammatory programmed cell death, in the pathogenesis of two chronic dermatoses, psoriasis and hidradenitis suppurativa (HS). The diseases, though clinically diverse, share common pathogenetic pathways involving the unbalanced interaction between the adaptive and innate immune systems. This review focuses on the molecular changes in psoriatic and HS skin, emphasizing the activation of dendritic cells, secretion of interleukins (IL-17, IL-22, and TNF-α), and the involvement of inflammasomes, particularly NLRP3. This manuscript discusses the role of caspases, especially caspase-1, in driving pyroptosis and highlights the family of gasdermins (GSDMs) as key players in the formation of pores leading to cell rupture and the release of proinflammatory signals. This study delves into the potential therapeutic implications of targeting pyroptosis in psoriasis and HS, examining existing medications like biologics and Janus kinase inhibitors. It also reviews the current limitations and challenges in developing therapies that selectively target pyroptosis. Additionally, the manuscript explores the role of pyroptosis in various inflammatory disorders associated with psoriasis and HS, such as inflammatory bowel disease, diabetes mellitus, and cardiovascular disorders. The review concludes by emphasizing the need for further research to fully elucidate the pathomechanisms of these dermatoses and develop effective, targeted therapies.

The antibacterial activity of berberine against Cutibacterium acnes: its therapeutic potential in inflammatory acne

Cutibacterium acnes (C. acnes) is a major pathogen implicated in the evolution of acne inflammation. Inhibition of C. acnes-induced inflammation is a prospective acne therapy strategy. Berberine (BBR), a safe and effective natural ingredient, has been proven to exhibit powerful antimicrobial and anti-inflammatory properties. However, the antimicrobial effect of BBR against C. acnes and its role in C. acnes-mediated inflammatory acne have not been explored. The objective of this investigation was to assess the antibacterial activity of BBR against C. acnes and its inhibitory effect on the inflammatory response. The results of in vitro experiments showed that BBR exhibited significant inhibition zones against four C. acnes strains, with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in the range of 6.25-12.5 μg/mL and 12.5-25 μg/mL, respectively. On the bacterial growth curve, the BBR-treated C. acnes exhibited obvious growth inhibition. Transmission electron microscopy (TEM) images indicated that BBR treatment resulted in significant morphological changes in C. acnes. High-content imaging analysis further confirmed that BBR could effectively inhibit the proliferation of C. acnes. The disruption of cell wall and cell membrane structure by BBR treatment was preliminary confirmed according to the leakage of cellular contents such as potassium (K+), magnesium (Mg2+), and alkaline phosphatase (AKP). Furthermore, we found that BBR could reduce the transcript levels of genes associated with peptidoglycan synthesis (murC, murD, mraY, and murG). Meanwhile, we investigated the modulatory ability of BBR on C. acnes-induced skin inflammation in mice. The results showed that BBR effectively reduced the number of C. acnes colonized in mice's ears, thereby alleviating ear swelling and erythema and significantly decreasing ear thickness and weight. In addition, BBR significantly decreased the levels of pro-inflammatory cytokines IL-6, IL-1β, and TNF-α in auricular tissues. These results suggest that BBR has the potential to treat inflammatory acne induced by C. acnes.

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

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

Novel anti-psoriatic nanostructured lipid carriers for the cutaneous delivery of luteolin: A comprehensive in-vitro and in-vivo evaluation

Psoriasis is a prevalent laborious inflammation in skin with alternate phases of remission and relapses. The current study sought to develop nanostructured lipid carriers (NLCs) having enhanced skin deposition as well as augmented anti-inflammatory potential, to repurpose the use of luteolin (Lut), a flavonoid, in the treatment of psoriasis. NLCs were prepared using different oils having reported anti-inflammatory activity and evaluated in terms of size, surface charge, entrapment efficiency, stability upon storage, in-vitro anti-inflammatory potential, surface morphology, in-vitro release profile and release kinetics, and ex-vivo skin deposition. In-vivo animal studies were conducted on the optimized formula using imiquimod-induced psoriasis rat model. The prepared NLCs were nanosized ranging from 202 to 538 nm, negatively charged with values having the range of -13.10 to -19.26 mV with high entrapment efficiency values ranging from 84.21 to 96.53% and high in-vitro anti-inflammatory potential compared to the blank and control formulations. Furthermore, NLCs demonstrated adequate storage stability demonstrated by slightly significant change in their colloidal properties. The prepared nanoparticles exhibited sustained drug release up to 24 h and succeeded in enhancing the skin deposition of Lut by 3.4-fold higher in stratum corneum, epidermis and dermis compared to Lut suspension with minimum transdermal delivery. In-vivo assessment of psoriasis was carried out morphologically, histopathologically and biochemically and results revealed significant augmentation of the anti-psoriatic efficacy of Lut upon its encapsulation in NLCs compared to free Lut suspension. The developed system proved to be an influential drug delivery system providing potent anti-psoriatic therapy, paving the way for futuristic clinical investigations.

Skin Barrier Function: The Interplay of Physical, Chemical, and Immunologic Properties

An intact barrier function of the skin is important in maintaining skin health. The regulation of the skin barrier depends on a multitude of molecular and immunological signaling pathways. By examining the regulation of a healthy skin barrier, including maintenance of the acid mantle and appropriate levels of ceramides, dermatologists can better formulate solutions to address issues that are related to a disrupted skin barrier. Conversely, by understanding specific skin barrier disruptions that are associated with specific conditions, such as atopic dermatitis or psoriasis, the development of new compounds could target signaling pathways to provide more effective relief for patients. We aim to review key factors mediating skin barrier regulation and inflammation, including skin acidity, interleukins, nuclear factor kappa B, and sirtuin 3. Furthermore, we will discuss current and emerging treatment options for skin barrier conditions.

Signaling pathways and targeted therapies for psoriasis

Psoriasis is a common, chronic, and inflammatory skin disease with a high burden on individuals, health systems, and society worldwide. With the immunological pathologies and pathogenesis of psoriasis becoming gradually revealed, the therapeutic approaches for this disease have gained revolutionary progress. Nevertheless, the mechanisms of less common forms of psoriasis remain elusive. Furthermore, severe adverse effects and the recurrence of disease upon treatment cessation should be noted and addressed during the treatment, which, however, has been rarely explored with the integration of preliminary findings. Therefore, it is crucial to have a comprehensive understanding of the mechanisms behind psoriasis pathogenesis, which might offer new insights for research and lead to more substantive progress in therapeutic approaches and expand clinical options for psoriasis treatment. In this review, we looked to briefly introduce the epidemiology, clinical subtypes, pathophysiology, and comorbidities of psoriasis and systematically discuss the signaling pathways involving extracellular cytokines and intracellular transmission, as well as the cross-talk between them. In the discussion, we also paid more attention to the potential metabolic and epigenetic mechanisms of psoriasis and the molecular mechanistic cascades related to its comorbidities. This review also outlined current treatment for psoriasis, especially targeted therapies and novel therapeutic strategies, as well as the potential mechanism of disease recurrence.

Sulforaphane alleviates psoriasis by enhancing antioxidant defense through KEAP1-NRF2 Pathway activation and attenuating inflammatory signaling

Psoriasis is a chronic inflammatory skin disease that affects millions of people worldwide. Sulforaphane (SFN) has been shown to have anti-inflammatory and antioxidant properties. In this study, we investigated the effects of SFN on a mouse model of psoriasis induced by imiquimod (IMQ) and its underlying molecular mechanism. Mice treated with SFN showed significant improvement in psoriatic symptoms, including reduced erythema, scales, and cutaneous thickness. Histopathological analysis and immunohistochemical staining revealed decreased expression of K16, K17, and Ki67 in SFN-treated mice, indicating reduced abnormal differentiation of keratinocytes and cutaneous inflammation. SFN treatment also reduced the activation of STAT3 and NF-κB pathways and downregulated pro-inflammatory cytokines IL-1β, IL-6, and CCL2. In vitro experiments using HaCaT cells demonstrated that SFN inhibited IL-22 and TNF-α-induced activation of inflammatory pathways and keratinocyte proliferation. Network pharmacology analysis suggested that the KEAP1-NRF2 pathway might be involved in the protective effects of SFN on psoriasis. We observed reduced NRF2 expression in human psoriatic lesions, and subsequent experiments showed that SFN activated KEAP1-NRF2 pathway in vivo and in vitro. Importantly, NRF2-deficient mice exhibited aggravated psoriasis-like symptoms and reduced response to SFN treatment. Our findings indicate that SFN ameliorates psoriasis symptoms and inflammation through the KEAP1-NRF2 pathway, suggesting a potential therapeutic role for SFN in the treatment of psoriasis.

γδ T cells: origin and fate, subsets, diseases and immunotherapy

The intricacy of diseases, shaped by intrinsic processes like immune system exhaustion and hyperactivation, highlights the potential of immune renormalization as a promising strategy in disease treatment. In recent years, our primary focus has centered on γδ T cell-based immunotherapy, particularly pioneering the use of allogeneic Vδ2+ γδ T cells for treating late-stage solid tumors and tuberculosis patients. However, we recognize untapped potential and optimization opportunities to fully harness γδ T cell effector functions in immunotherapy. This review aims to thoroughly examine γδ T cell immunology and its role in diseases. Initially, we elucidate functional differences between γδ T cells and their αβ T cell counterparts. We also provide an overview of major milestones in γδ T cell research since their discovery in 1984. Furthermore, we delve into the intricate biological processes governing their origin, development, fate decisions, and T cell receptor (TCR) rearrangement within the thymus. By examining the mechanisms underlying the anti-tumor functions of distinct γδ T cell subtypes based on γδTCR structure or cytokine release, we emphasize the importance of accurate subtyping in understanding γδ T cell function. We also explore the microenvironment-dependent functions of γδ T cell subsets, particularly in infectious diseases, autoimmune conditions, hematological malignancies, and solid tumors. Finally, we propose future strategies for utilizing allogeneic γδ T cells in tumor immunotherapy. Through this comprehensive review, we aim to provide readers with a holistic understanding of the molecular fundamentals and translational research frontiers of γδ T cells, ultimately contributing to further advancements in harnessing the therapeutic potential of γδ T cells.

Architecture of skin inflammation in psoriasis revealed by spatial transcriptomics

Psoriasis is a chronic inflammatory skin disease, thought to be predominantly mediated by TH17 cells. Significance of other inflammatory pathways and the innate immune system is not well understood and the spatial heterogeneity of inflammation in the skin has largely been overlooked. Our aim was to create a comprehensive map of skin inflammation in psoriasis, exploring the tissue patterning of inflammation. In situ whole transcriptome sequencing (spatial sequencing) was performed on lesional psoriatic skin in four patients with moderate-to-severe disease to quantify all expressed genes within a tissue section. Transcriptional analysis revealed three major inflammatory niches in psoriasis skin, each with distinct cytokine circuits and chemokines: the hyperplastic epidermis, upper (papillary) dermis, and reticular dermis. Interestingly, key cytokines such as IL-23, IL-17 s, and TNFα were not notably present in the skin's transcriptomic signature. Unexpectedly, IL-32 showed strong expression in the dermis. Our findings underscore the complexity of psoriatic inflammation, highlighting its architectural heterogeneity and the roles of innate cytokines. Both IL-32 and IL-1 family cytokines appear to play critical roles in the dermal and epidermal inflammation, respectively, and may provide pharmacological targets to improve the control of the inflammatory process.