Journal of dermatological science最新文献

Background: Olmsted syndrome (OS) is a rare genodermatosis predominantly inherited in an autosomal dominant manner, typically arising from gain-of-function (GOF) variants in the transient receptor potential channel vanilloid 3 (TRPV3) gene.

Objective: This study aims to investigate potential mechanisms underlying OS in two cases presenting with an autosomal recessive inheritance pattern.

Methods: Next-generation sequencing panel was employed to identify TRPV3 variants. TRPV3 plasmids carrying specific point variations were generated and transiently transfected into HEK293T cells. Electrophysiological patch-clamp techniques were utilized to record voltage-activated and ligand-activated currents. Celltiter-Glo luminescent assay was employed to analyze the cell viabilities.

Results: Compound heterozygous variants, c.1563 G>C (p.W521C) and c.1376 C>T (p.S459L), as well as c.1773 G>C (p.L591F) and c.2186 G>A (p.R729Q), were identified in the two OS patients respectively. Electrophysiological analysis of ligand-induced activation of TRPV3 variants demonstrated the closest correlation with clinical manifestations. All four variants displayed GOF channel activity characterized by increased sensitivity. Notably, W521C and L591F exhibited both heightened sensitivity and lower EC50 values for the TRPV3 agonist. Co-transfection with wild-type TRPV3 plasmids significantly rescued these effects. Cells co-transfected with the corresponding compound heterozygous variants exhibited intermediate electrophysiological characteristics.

Conclusions: In this study, we present two cases of OS by autosomal-recessive inheritance of TPRV3 variants. This study presents a notable observation of compound heterozygous GOF variants in TRPV3, highlighting their cumulative impact on clinical manifestations. Additionally, we advocate for the use of ligand-dependent ion channel activity assays to assess the pathogenicity of TRPV3 variants in OS.

Background: Psoriasis is a chronic inflammatory skin disease that affects a significant proportion of the global population. The involvement of S-adenosine homocysteine hydrolase (AHCY) in psoriasis and its impact on DNA methylation have not been extensively studied.

Objective: This study aimed to investigate the role of AHCY and its impact on DNA methylation in psoriasis pathogenesis.

Methods: In the present study, we investigated the expression of AHCY in psoriatic lesions and assessed its association with the severity of the disease. Moreover, knockdown experiments were conducted to elucidate the impact of AHCY on psoriatic symptoms, keratinocyte proliferation, and aberrant differentiation. Furthermore, alterations in DNA methylation patterns resulting from AHCY knockdown were analyzed.

Results: Our findings revealed that AHCY was upregulated in psoriatic lesions and exhibited a positive correlation with disease severity. Knockdown of AHCY alleviated psoriatic symptoms, inhibited keratinocyte proliferation, and prevented abnormal differentiation. Moreover, AHCY knockdown led to reduced levels of DNA methylation and alterations in methylation patterns. Notably, differential methylation was observed at specific gene loci associated with psoriasis-related inflammation.

Conclusion: This study highlights the potential role of AHCY in psoriasis development through its influence on DNA methylation. The findings underscore the complex interaction among AHCY, epigenetic modifications, and inflammation in the pathogenesis of psoriasis. Consequently, AHCY may serve as a promising therapeutic target for psoriasis treatment.

Background: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe adverse drug reactions with extensive keratinocyte death. Carbamazepine (CBZ), the most commonly implicated drug in SJS/TEN, is metabolized by the cytochrome P450 enzyme 3A4 (CYP3A4) into carbamazepine-10,11-epoxide (CBZE) in the liver. While CD8⁺ cytotoxic T cells play an important role in SJS/TEN, the underlying mechanism of exuberant immune response by CD8⁺ T cells in these conditions remains incompletely understood.

Objectives: To examine the expression of NLRP3 inflammasome and their skin migration in CBZE-induced SJS/TEN.

Methods: The expression of the NLRP3 inflammasome complex in skin lesions, sera, and blister fluids of SJS/TEN patients were analyzed by immunohistochemistry and enzyme-linked immunosorbent assay. NLRP3 formation and CD8⁺ T cell activation status and their functions were examined by immunoblotting, immunofluorescence, and chemotaxis assays.

Results: The expression of the NLRP3 inflammasome complex was greatly increased in skin lesions of SJS/TEN patients. Moreover, IL-1β and IL-18 levels in sera and blister fluids of SJS/TEN patients were approximately 3-fold higher than those in healthy individuals, with a linear correlation between IL-1β levels and disease activity. CBZE induced NLRP3 inflammasome formation, upregulated CXCL9/CXCL10 levels, and activated CD8⁺ cytotoxic T cell functions via IL-1β/IL-1R or IL-18/IL-18R signaling in SJS/TEN keratinocytes, which promoted CD8⁺ cytotoxic T cell migration in SJS/TEN patients.

Conclusion: This study showed that CBZE promoted NLRP3 inflammasome formation and strengthened the activation and function of CD8⁺ cytotoxic T cells in the skin, which contributed to the initiation and progression of SJS/TEN.

Background: Cell death constitutes a pivotal biological phenomenon essential for the preservation of homeostasis within living organisms. In the context of maintaining a functional skin barrier, keratinocytes exert positively and negatively control cell death signals. However, in patients with severe drug eruptions, anomalous overexpression of the formyl peptide receptor 1 (FPR1) in keratinocytes elicits a distinctive mode of cell death known as necroptosis, thereby suffering a loss of the skin barrier. The precise molecular mechanisms connecting FPR1 activation to this cell death remain unclear.

Objective: We have investigated the intracellular signal transduction cascade governing FPR1-mediated cell death in cultured keratinocytes.

Methods: We used HaCaT cells as a model keratinocyte. The expression of FPR1 was detected with qPCR. The presence of cell death events was monitored through live-cell fluorescent staining and LDH release assays. Furthermore, the phosphorylation of ERK was assessed via Western blot analysis. Intracellular signal pathways were investigated using specific inhibitors.

Results: Ligand stimulation of an endogenous ion channel, purinergic receptor P2X7 (P2X7R), increased the FPR1 expression level. This upregulated FPR1 demonstrated functional competence in the phosphorylation of downstream MAP kinase and the initiation of cell death. Notably, this cell death was ameliorated upon the administration of inhibitors targeting Gβγ, ERK, and caspases.

Conclusion: The induction and stimulation of FPR1 initiated apoptosis in keratinocytes via the Gβγ-pERK signaling pathway. Our findings postulate that the downstream components of FPR1 represent an alternative therapeutic target for preventing unintended keratinocyte cell death.