Keratinocyte FABP5-VCP complex mediates recruitment of neutrophils in psoriasis

Apocrine Gland Damage and the Release of Specific Keratins in Early Stage Indicate the Crucial Involvement of Apocrine Glands in Hidradenitis Suppurativa

The apocrine glands (AGs) are not considered to be primarily involved in hidradenitis suppurativa (HS). This study investigated the potential role of AGs in HS pathogenesis using immunohistochemistry and single-cell sequencing of nonlesional skin and early lesional skin (LS) from patients with HS (n = 12) and healthy controls (n = 8). AG cell destruction was more frequent, and AG size was significantly reduced in the nonlesional skin and LS. Barrier-related genes (eg, CLDN1 and CDH1) were downregulated in the AGs of the nonlesional skin and LS. Damaged AGs in the LS primarily recruited and activated neutrophils through the CXCL-CXCR and SAA1-FPR2 pathways. Elevated levels of specific keratins (keratin 18 and keratin 19) released from damaged AGs were observed on the skin surface of patients and were associated with disease severity. Keratin 19 was also detected in the dermis of the nonlesional skin and LS and was surrounded by neutrophils and macrophages. Moreover, serum keratin 19 levels in patients (N = 20) were significantly negatively correlated with the age at HS onset. Collectively, our findings provide previously unreported evidence that the AGs are damaged and release specific keratins in early HS lesions, indicating a crucial role of the AGs in HS pathogenesis.

ART26.12, an FABP5 Inhibitor, Shows Efficacy in Preclinical Psoriasis Models

FABP5 is upregulated in psoriasis. This study assessed the efficacy of the potent, selective, and orally active FABP5 inhibitor ART26.12 in preclinical psoriasis models. In vitro, reconstructed human epidermis was stimulated with cytokines (IL-17 + IL-22 + TNF at 3 ng/ml each) and treated with ART26.12 (1, 3, or 10 μM) or Jak1 inhibitor (10 μM) for 24 hours; after which, 64 psoriasis-related genes were measured. ART26.12 (3 and 10 μM) treatment reduced cytokines, chemokines, and markers of keratinocyte proliferation/differentiation and increased certain antimicrobial peptides. In vivo, ART26.12 (25 or 100 mg/kg twice a day) or BMS-986165 (TYK2 inhibitor; 10 mg/kg once a day) was given orally for 10 days in the imiquimod mouse model. Imiquimod increased psoriasis-like symptoms. ART26.12 (25 mg/kg twice a day) and BMS-986165 comparably reduced psoriasis-like symptoms by day 6 of imiquimod treatment. Histopathology showed that ART26.12 reduced symptom severity, for example, hyperkeratosis, parakeratosis, epidermal acanthosis, and inflammatory infiltrates. Proteomic analysis indicated that ART26.12 rescued the expression of FLG-2; promoted epidermal differentiation complex-associated proteins; and modulated peroxisome proliferator-activated receptor, NF-kB, and protein kinase C pathways likely downstream of lipid modulation. Lipidomic analysis showed widespread modulation, including ceramides and linoleic acid derivatives. These data suggest that ART26.12 may be a potential psoriasis treatment.

Identifying nexilin as a central gene in neutrophil-driven abdominal aortic aneurysm pathogenesis

OBJECTIVES

Abdominal aortic aneurysm (AAA) is an inflammation-driven disease in which neutrophil infiltration is critical to its progression. This study aims to explore the molecular mechanisms behind neutrophil infiltration in AAA and identify key regulatory genes.

METHODS

We utilized weighted gene co-expression network analysis (WGCNA) and differential gene expression analysis to compare AAA and healthy abdominal aortic tissues. Functional enrichment analysis and a protein-protein interaction (PPI) network were constructed to understand gene functions. Machine learning algorithms were applied to identify key hub genes, followed by in vivo validation using an ApoE-/- mouse model.

RESULTS

Neutrophils, NK cells, and pDCs were significantly increased in AAA tissues. WGCNA identified 234 genes associated with neutrophil infiltration, of which 39 were significantly differentially expressed. Functional enrichment analysis highlighted roles in actin-related processes and pathways. Nexilin (NEXN) was consistently identified as a key hub gene negatively correlated with immune cell infiltration. In vivo validation confirmed that NEXN inhibits AAA progression in ApoE-/- mice by regulating immune cell infiltration.

CONCLUSION

NEXN plays a crucial role in modulating neutrophil infiltration in AAA. These findings provide new molecular insights into AAA pathogenesis and suggest NEXN as a potential target for AAA therapy.

Psoriatic arthritis in psoriasis: optimizing the current screening system for psoriatic arthritis based on serum data from U.S. and Chinese populations

Background

Psoriatic arthritis (PSA) is an inflammatory joint disease associated with psoriasis (PSO) that can be easily missed. Existing PSA screening tools ignore objective serologic indicators. The aim of this study was to develop a disease screening model and the Psoriatic Arthritis Inflammation Index (PSAII) based on serologic data to enhance the efficiency of PSA screening.

Method

A total of 719 PSO and PSA patients from the National Health and Nutrition Examination Survey (NHANES) (as training set and test set) and 135 PSO and PSA patients who were seen at The First Affiliated Hospital of Zhejiang Chinese Medical University (as external validation set) were selected, 31 indicators for these patients were collected as potential input features for the model. Least Absolute Shrinkage and Selection Operator (LASSO) was used to identify PSA-related features. Five models of logistic regression (LR), random forest, k-nearest neighbor, gradient augmentation and neural network were developed in the training set using quintuple cross validation. And we developed PSAII based on the results of LASSO regression and weights of logistic model parameters. All performance metrics are derived on the test set and the external validation set.

Results

Five variables were selected to build models, including age, lymphocyte percentage, neutrophil count, eosinophilic count, and C-reactive protein. In all established models, the LR model performed the best, with an Area Under Curve (AUC) of 0.87 (95% confidence interval (CI): 0.83-0.90) on the test set; on the external validation set the AUC was 0.82 (95%CI: 0.74-0.90). The PSAII formula was PSAII = percentage of lymphocytes × C-reactive protein/(neutrophil count × eosinophilic count × 10). The AUC of PSAII in the test is 0.93 (95%CI: 0.88-0.97), and the cutoff value is 18. The AUC of the external validation set is 0.81 (95%CI: 0.72-0.89).

Conclusions

This study developed and validated five models to assist screening for PSA by analyzing serum data from NHANES and Chinese populations. The LR model demonstrated the best performance. We created PSAII for PSA screening. However, the high false positive rate of PSAII makes it necessary to combine it with other PSA screening tools when applied.

Advances in the mechanism of action of short-chain fatty acids in psoriasis

Psoriasis is a prevalent chronic inflammatory and immunological disorder. Its lesions are present as scaly erythema or plaques. Disruptions in the body's immune system play a significant role in developing psoriasis. Recent evidence suggests a potential role of the gut microbiome in autoimmune diseases. Short-chain fatty acids (SCFAs) are the primary metabolites created by gut microbes and play a crucial fuction in autoimmunity. SCFAs act on various cells by mediating signaling to participate in host physiological and pathological processes. These processes encompass body metabolism, maintenance of intestinal barrier function, and immune system modulation. SCFAs can regulate immune cells to enhance the body's immune function, potentially influencing the prevention and treatment of psoriasis. However, the mechanisms underlying the role of SCFAs in psoriasis remain incompletely understood. This paper examines the relationship between SCFAs and psoriasis, elucidating how SCFAs influence the immune system, inflammatory response, and gut barrier in psoriasis. According to the study, in psoriasis, SCFAs have been shown to regulate neutrophils, macrophages, and dendritic cells in the adaptive immune system, as well as T and B cells in the innate immune system. Additionally, we explore the role of SCFAs in psoriasis by maintaining intestinal barrier function, restoring intestinal ecological homeostasis, and investigating the potential therapeutic benefits of SCFAs for psoriasis.

Molecular mechanisms of obesity predisposes to atopic dermatitis

Obesity is a prevalent metabolic disease that reduces bacterial diversity, colonizes the epidermis with lipophilic bacteria, and increases intestinal pro-inflammatory species, all of which lead to impaired epithelial barriers. Adipose tissue secretes immunomodulatory molecules, such as adipokines, leptin, and adiponectin, which alters the morphology of adipocytes and macrophages as well as modulates T cell differentiation and peripheral Th2-dominated immune responses. Atopic dermatitis (AD) and obesity have similar pathological manifestations, including inflammation as well as insulin and leptin resistance. This review examines the major mechanisms between obesity and AD, which focus on the effect on skin and gut microbiota, immune responses mediated by the toll like receptor (TLR) signaling pathway, and changes in cytokine levels (TNF-a, IL-6, IL-4, and IL13). Moreover, we describe the potential effects of adipokines on AD and finally mechanisms by which PPAR-γ suppresses and regulates type 2 immunity.

Distinct adaptive immune receptor feature of adipose-derived mesenchymal stem cells (AD-MSCs) treatment of psoriasis

Psoriasis (Ps) is one of the most common chronic inflammatory skin disorders with its pathogenesis correlated with dysregulated innate and adaptive system. Even though biological agents have advanced the treatment of psoriasis, however, there are huge limitations, like high adverse reactions and relapse rate. Therefore, it is of great interest in searching clinical resolutions with better safety and efficacy. In the current study, we utilized the adipose-derived mesenchymal stem cell (AD-MSCs) to treat moderate/severe cases of psoriasis in a single-arm clinical study. This AD-MSC treatment has proven to be clinically safe and effective. Interestingly, a trend of adaptome improvement, including increased diversity, elevated uCDR3s and decreased large clone after AD-MSC treatment in a short (2 weeks) and long (12 weeks) terms. In conclusion, allogenic AD-MSC treatment has shown a good safety and efficacy in treating Ps and can effectively improve the compromised adaptive immune system of Ps patients.

Determination of the FABP5 expression profile in skin lesions of an IMQ-induced psoriasis mouse model using flow cytometry

The fatty acid-binding protein 5 (FABP5) is a key player in psoriasis development. Therefore, characterizing the expression profile of FABP5 in various cell types within both layers of psoriatic skin is important. Here, we present a protocol that describes steps for an imiquimod-induced psoriasis mouse model and preparation of epidermal and dermal single-cell suspensions. We then detail procedures to detect the FABP5 expression profile in skin keratinocytes and immune cells using intracellular flow cytometry staining. For complete details on the use and execution of this protocol, please refer to Hao et al.1.

Natural Product-Derived Compounds Targeting Keratinocytes and Molecular Pathways in Psoriasis Therapeutics

Psoriasis is a chronic autoimmune inflammatory skin disorder that affects approximately 2-3% of the global population due to significant genetic predisposition. It is characterized by an uncontrolled growth and differentiation of keratinocytes, leading to the formation of scaly erythematous plaques. Psoriasis extends beyond dermatological manifestations to impact joints and nails and is often associated with systemic disorders. Although traditional treatments provide relief, their use is limited by potential side effects and the chronic nature of the disease. This review aims to discuss the therapeutic potential of keratinocyte-targeting natural products in psoriasis and highlight their efficacy and safety in comparison with conventional treatments. This review comprehensively examines psoriasis pathogenesis within keratinocytes and the various related signaling pathways (such as JAK-STAT and NF-κB) and cytokines. It presents molecular targets such as high-mobility group box-1 (HMGB1), dual-specificity phosphatase-1 (DUSP1), and the aryl hydrocarbon receptor (AhR) for treating psoriasis. It evaluates the ability of natural compounds such as luteolin, piperine, and glycyrrhizin to modulate psoriasis-related pathways. Finally, it offers insights into alternative and sustainable treatment options with fewer side effects.