Macrophage P2Y6R activation aggravates psoriatic inflammation through IL-27-mediated Th1 responses

Decoding Macrophage Dynamics: A Pathway to Understanding and Treating Inflammatory Skin Diseases

Psoriasis and atopic dermatitis (AD) are both chronic inflammatory skin diseases. Their pathogenesis remains incompletely understood. The polarization states of macrophages, as a crucial part of the innate immune system, are influenced by various factors such as cytokines, inflammatory mediators, and epigenetics. Research has demonstrated that macrophages play a "double-edged sword" role in the pathological process of inflammatory skin diseases: they both drive inflammation progression and participate in tissue repair. This article summarizes the roles of macrophages in the inflammatory development and tissue homeostasis of psoriasis and atopic dermatitis. It explores the impact of different factors on macrophages and inflammatory skin diseases. In conclusion, understanding the classification and plasticity of macrophages is crucial for a deeper understanding of the pathogenesis of psoriasis and AD and the development of personalized treatments.

P2Y6 promoted pruning of FSTL1 nerves by cutaneous macrophages to reset pain threshold and cardiac function

Hyperactivation of cutaneous macrophages promotes the development of chronic pain. Stimulation of nociceptive regions promotes neuroplasticity, which affects pain perception and related physiological responses. However, the specific mechanisms by which cutaneous macrophages sense and elicit nociceptive responses are unknown. Here, we exacerbated the reduction of systemic pain threshold after chronic heart failure (CHF) by silencing follistatin-like 1 (FSTL1), especially the abnormal cutaneous nociceptive sensation at PC6 acupoint, the site associated with cardiac involvement pain. The upregulation of P2Y6 and interleukin-27 expression is intimately linked to the activation of skin macrophages. Hyperactivation of P2Y6 receptor (P2Y6R) may be associated with MHC II M1+ macrophage polarization in PC6. Thus, P2Y6 is one of the key factors that modulate the functional polarization of skin macrophages, which may subsequently influence the expansion of the pain field. The supportive effect of CD206 M2+ macrophages on the cutaneous FSTL1+ nerves was significantly reduced. Meanwhile, FSTL1+ nerves in PC6 functionally interacted with calcitonin gene-related peptide (CGRP)+ nerves, and the overactivation of nerve growth factor (NGF) secreted by cutaneous macrophages induced CGRP+ neuropathological remodeling, which supported the enlargement of the pain sensory area. The activation of CGRP and P2X3 receptor (P2X3R), Na+/K+ ATPase (NKA), and P2X3R in the C8 DRG may be one of the molecular bases mediating cutaneous nociceptive transmission and affecting the function of the heart. Hyperactivation of NKA was consistent with decreased pain threshold and changes in cardiac dysfunction, and PC6 injection of an NKA inhibitor (digilanid C) was effective in ameliorating nociception and cardiac impairment. The beneficial effects of digilanid C were counteracted by FSTL1 silencing. These results indicated that P2Y6 mediates the remodeling of pain perception by skin macrophages via the action of FSTL1, while NKA inhibitors synergistically exert their therapeutic effects.

Celastrol directly targets LRP1 to inhibit fibroblast-macrophage crosstalk and ameliorates psoriasis progression

Psoriasis is an incurable chronic inflammatory disease that requires new interventions. Here, we found that fibroblasts exacerbate psoriasis progression by promoting macrophage recruitment via CCL2 secretion by single-cell multi-omics analysis. The natural small molecule celastrol was screened to interfere with the secretion of CCL2 by fibroblasts and improve the psoriasis-like symptoms in both murine and cynomolgus monkey models. Mechanistically, celastrol directly bound to the low-density lipoprotein receptor-related protein 1 (LRP1) β-chain and abolished its binding to the transcription factor c-Jun in the nucleus, which in turn inhibited CCL2 production by skin fibroblasts, blocked fibroblast-macrophage crosstalk, and ameliorated psoriasis progression. Notably, fibroblast-specific LRP1 knockout mice exhibited a significant reduction in psoriasis like inflammation. Taken together, from clinical samples and combined with various mouse models, we revealed the pathogenesis of psoriasis from the perspective of fibroblast-macrophage crosstalk, and provided a foundation for LRP1 as a novel potential target for psoriasis treatment.

Skin Metabolic Signatures of Psoriasis and Psoriasis Concurrent with Metabolic Syndrome

Purpose

Psoriasis is a complex inflammatory skin disorder that is closely associated with metabolic syndrome (MetS). Limited information is available on skin metabolic changes in psoriasis; the effect of concurrent MetS on psoriatic skin metabolite levels is unknown. We aimed to expand this information through skin metabolomic analysis.

Patients and Methods

Untargeted metabolomics was conducted using skin samples from 38 patients with psoriasis vulgaris with MetS (PVMS), 23 patients with psoriasis vulgaris without MetS (PVNMS), and 10 healthy controls (HC). Data analyses, including multivariate statistical analysis, KEGG pathway enrichment analysis, correlation analysis, and receiver operating characteristic curve analysis, were performed.

Results

Significant discrepancies were found between skin metabolites in the HC and PVNMS groups, particularly those involved in nucleotide and glycerophospholipid metabolism. Fifteen of these metabolites were positively correlated with psoriasis severity. Furthermore, MetS was found to affect the metabolic profiles of patients with psoriasis. There were some metabolites with consistent alterations in both the PVNMS/HC and PVMS/PVNMS comparisons.

Conclusion

This study may provide new insights into the link between skin metabolism and psoriatic inflammation and the mechanism underlying the interaction between psoriasis and MetS.

Nanocarrier-Based Transdermal Drug Delivery Systems for Dermatological Therapy

Dermatoses are among the most prevalent non-fatal conditions worldwide. Given this context, it is imperative to introduce safe and effective dermatological treatments to address the diverse needs and concerns of individuals. Transdermal delivery technology offers a promising alternative compared to traditional administration methods such as oral or injection routes. Therefore, this review focuses on the recent achievements of nanocarrier-based transdermal delivery technology for dermatological therapy, which summarizes diverse delivery strategies to enhance skin penetration using various nanocarriers including vesicular nanocarriers, lipid-based nanocarriers, emulsion-based nanocarriers, and polymeric nanocarrier according to the pathogenesis of common dermatoses. The fundamentals of transdermal delivery including skin physiology structure and routes of penetration are introduced. Moreover, mechanisms to enhance skin penetration due to the utilization of nanocarriers such as skin hydration, system deformability, disruption of the stratum corneum, surface charge, and tunable particle size are outlined as well.

Functionalized Congeners of 2H-Chromene P2Y6 Receptor Antagonists

The P2Y6 receptor (P2Y6R), a Gq-coupled receptor, is a potential drug discovery target for various inflammatory and degenerative conditions. Antagonists have been shown to attenuate colitis, acute lung injury, etc. In the search for competitive antagonists, we have investigated the SAR of 3-nitro-2-(trifluoromethyl)-2H-chromene derivatives, although high affinity is lacking. We now reveal that long-chain amino-functionalized congeners display greatly enhanced affinity in the antagonism of UDP-induced Ca2+ mobilization in human (h) P2Y6R-transfected 1321N1 astrocytoma cells. A 6-(Boc-amino-n-heptylethynyl) analogue 30 (MRS4940) had an IC50 of 162 nM, which was a 123-fold greater affinity than the corresponding unprotected primary alkylamine, 107-fold greater than the corresponding pivaloyl derivative 30, and 132-fold selective compared to the P2Y14R. However, similar Boc-amino chains attached at the 8-position produced weak µM affinity. Thus, the P2Y6R affinity depended on the chain length, attachment point, and terminal functionality. Off-target activities, at 45 sites, were tested for acylamino derivatives 20, 24, 26, 30, 31, and 37, which showed multiple interactions, particularly at the biogenic amine receptors. The more potent analogues may be suitable for evaluation in inflammation and cancer models, which will be performed in future studies.