Eosinophil extracellular traps drive T follicular helper cell differentiation via VIRMA-dependent MAF stabilization in bullous pemphigoid.

BACKGROUND: Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by the presence of pathogenic autoantibodies and a substantial influx of immune cells into skin lesions. However, the role of eosinophils in BP remain inadequately elucidated. OBJECTIVE: We sought to determine the pathological involvement of eosinophils and eosinophil extracellular traps (EETs) in BP. METHODS: Human samples collected from BP patients and healthy controls were utilized to explore the potential role of eosinophils and their EETs in BP patients through serological detection, flow cytometry, and immunofluorescence. Naïve CD4+ T cells isolated from healthy donors were stimulated and subjected to further analysis via RNA sequencing. We additionally evaluated the potential of targeting EETs in BP180-immunized BP-like mice and in vitro settings. RESULTS: We found that elevated levels of eosinophils and EETs in BP patients correlated with disease severity. The DNA components within EETs played a crucial role in driving the differentiation of naïve CD4+ T cells into follicular helper T cells (Tfh) by activating coil domains containing 25 (CCDC25). Treatment with DNase I which disrupts the structural integrity of EETs, or neutralizing antibody against CCDC25 reduced the expansion of Tfh cells and suppressed the production of autoantibodies in BP180-immunized BP-like mouse models. Additionally, we discovered that EETs induced the N6-methyladenosine (m6A) methylation of the transcription factor MAF via the DNA-CCDC25-VIRMA pathway, thereby enhancing its mRNA stability and promoting Tfh cell differentiation. CONCLUSION: Our study reveals a previously unrecognized mechanism by which EETs trigger abnormal Tfh cell differentiation through CCDC25, followed by VIRMA-mediated m6A modification of MAF. These insights provide promising avenues for the development of targeted therapeutic interventions in the field of BP and potentially other autoimmune diseases.

Epidermal stem cells: skin surveillance and clinical perspective.

The skin epidermis is continually influenced by a myriad of internal and external elements. At its basal layer reside epidermal stem cells, which fuels epidermal renovation and hair regeneration with powerful self-renewal ability, as well as keeping diverse signals that direct their activity under surveillance with quick response. The importance of epidermal stem cells in wound healing and immune-related skin conditions has been increasingly recognized, and their potential for clinical applications is attracting attention. In this review, we delve into recent advancements and the various physiological and psychological factors that govern distinct epidermal stem cell populations, including psychological stress, mechanical forces, chronic aging, and circadian rhythm, as well as providing an overview of current methodological approaches. Furthermore, we discuss the pathogenic role of epidermal stem cells in immune-related skin disorders and their potential clinical applications.

Assessment of relationships between bullous pemphigoid and neurological diseases: A bidirectional two-sample Mendelian randomization study.

Bullous pemphigoid (BP) is the most prevalent autoimmune vesiculobullous skin illness that tends to affect the elderly. Growing evidence has hinted a correlation between BP and neurological diseases. However, existing observational studies contained inconsistent results, and the causality and direction of their relationship remain poorly understood. To assess the causal relationship between BP and neurological disorders, including Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease (PD), and stroke. A bidirectional two-sample Mendelian randomization (MR) adopted independent top genetic variants as instruments from the largest accessible genome-wide association studies (GWASs), with BP (n = 218 348), PD (n = 482 730), AD (n = 63 926), stroke (n = 446 696), and MS (n = 115 803). Inverse variance weighted (IVW), MR-Egger, weighted mode methods, weighted median, and simple mode were performed to explore the causal association. Multiple sensitivity analyses, MR-Pleiotropy Residual Sum and Outlier (PRESSO) was used to evaluate horizontal pleiotropy and remove outliers. With close-to-zero effect estimates, no causal impact of BP on the risk of the four neurological diseases was discovered. However, we found that MS was positively correlated with higher odds of BP (OR = 1.220, 95% CI: 1.058-1.408, p = 0.006), while no causal associations were observed between PD (OR = 0.821, 95% CI: 0.616-1.093, p = 0.176), AD (OR = 1.066, 95% CI: 0.873-1.358, p = 0.603), stroke (OR = 0.911, 95% CI: 0.485-1.713, p = 0.773) and odds of BP. In summary, no causal impact of BP on the risk of PD, AD, MS and stroke was detected in our MR analysis. However, reverse MR analysis identified that only MS was positively correlated with higher odds of BP, but not PD, AD and stroke.

Formylpeptide receptor 1 contributes to epidermal barrier dysfunction-induced skin inflammation through NOD-like receptor C4-dependent keratinocyte activation.

BACKGROUND: Skin barrier dysfunction may both initiate and aggravate skin inflammation. However, the mechanisms involved in the inflammation process remain largely unknown. OBJECTIVES: We sought to determine how skin barrier dysfunction enhances skin inflammation and molecular mechanisms. METHODS: Skin barrier defect mice were established by tape stripping or topical use of acetone on wildtype mice, or filaggrin deficiency. RNA-Seq was employed to analyse the differentially expressed genes in mice with skin barrier defects. Primary human keratinocytes were transfected with formylpeptide receptor (FPR)1 or protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) small interfering RNA to examine the effects of these gene targets. The expressions of inflammasome NOD-like receptor (NLR)C4, epidermal barrier genes and inflammatory mediators were evaluated. RESULTS: Mechanical (tape stripping), chemical (acetone) or genetic (filaggrin deficiency) barrier disruption in mice amplified the expression of proinflammatory genes, with transcriptomic profiling revealing overexpression of formylpeptide receptor (Fpr1) in the epidermis. Treatment with the FPR1 agonist fMLP in keratinocytes upregulated the expression of the NLRC4 inflammasome and increased interleukin-1ß secretion through modulation of ER stress via the PERK-eIF2α-C/EBP homologous protein pathway. The activation of the FPR1-NLRC4 axis was also observed in skin specimens from old healthy individuals with skin barrier defect or elderly mice. Conversely, topical administration with a FPR1 antagonist, or Nlrc4 silencing, led to the normalization of barrier dysfunction and alleviation of inflammatory skin responses in vivo. CONCLUSIONS: In summary, our findings show that the FPR1-NLRC4 inflammasome axis is activated upon skin barrier disruption and may explain exaggerated inflammatory responses that are observed in disease states characterized by epidermal dysfunction. Pharmacological inhibition of FPR1 or NLRC4 represents a potential therapeutic target.

Serine deficiency exacerbates psoriatic skin inflammation by regulating S-adenosyl methionine-dependent DNA methylation and NF-κB signalling activation in keratinocytes.

BACKGROUND: Serine metabolism is crucial for tumour oncogenesis and immune responses. S-adenosyl methionine (SAM), a methyl donor, is typically derived from serine-driven one-carbon metabolism. However, the involvement of serine metabolism in psoriatic skin inflammation remains unclear. OBJECTIVES: To investigate the association between serine metabolism and psoriatic skin inflammation. METHODS: Clinical samples were collected from patients with psoriasis and the expression of serine biosynthesis enzymes was evaluated. The HaCaT human keratinocyte cell line was transfected with small interfering RNA (siRNA) of key enzyme or treated with inhibitors. RNA sequencing and DNA methylation assays were performed to elucidate the mechanisms underlying serine metabolism-regulated psoriatic keratinocyte inflammation. An imiquimod (IMQ)-induced psoriasis mouse model was established to determine the effect of the SAM administration on psoriatic skin inflammation. RESULTS: The expression of serine synthesis pathway enzymes, including the first rate-limiting enzyme in serine biosynthesis, phosphoglycerate dehydrogenase (PHGDH), was downregulated in the epidermal lesions of patients with psoriasis compared with that in healthy controls. Suppressing PHGDH in keratinocytes promoted the production of proinflammatory cytokines and enrichment of psoriatic-related signalling pathways, including the tumour necrosis factor-alpha (TNF-α) signalling pathway, interleukin (IL)-17 signalling pathway and NF-κB signalling pathway. In particular, PHGDH inhibition markedly promoted the secretion of IL-6 in keratinocytes with or without IL-17A, IL-22, IL-1α, oncostatin M and TNF-α (mix) stimulation. Mechanistically, PHGDH inhibition upregulated the expression of IL-6 by inhibiting SAM-dependent DNA methylation at the promoter and increasing the binding of myocyte enhancer factor 2A. Furthermore, PHGDH inhibition increased the secretion of IL-6 by increasing the activation of NF-κB via SAM inhibition. SAM treatment effectively alleviated IMQ-induced psoriasis-like skin inflammation in mice. CONCLUSIONS: Our study revealed the crucial role of PHGDH in antagonising psoriatic skin inflammation and indicated that targeting serine metabolism may represent a novel therapeutic strategy for treating psoriasis.

Cross-disease characterization of fibroblast heterogeneities and their pathogenic roles in skin inflammation.

Fibroblasts are critical pro-inflammatory regulators in chronic inflammatory and fibrotic skin diseases. However, fibroblast heterogeneity and the absence of a unified cross-disease taxonomy have hindered our understanding of the shared/distinct pathways in non-communicable skin inflammation. By integrating 10× single-cell data from 75 skin samples, we constructed a single-cell atlas across inflammatory and fibrotic skin diseases and identified 9 distinct subsets of skin fibroblasts. We found a shared subset of CCL19+ fibroblasts across these diseases, potentially attracting and educating immune cells. Moreover, COL6A5+ fibroblasts were a distinct subset implicated in the initiation and relapse of psoriasis, which tended to differentiate into CXCL1+ fibroblasts, inducing neutrophil chemotaxis and infiltration; while CXCL1+ fibroblasts exhibited a more heterogeneous response to certain inflammatory conditions. Differentiation trajectory and regulatory factors of these fibroblast subsets were also revealed. Therefore, our study presents a comprehensive atlas of skin fibroblasts and highlights pathogenic fibroblast subsets in skin disorders.

Neutrophil extracellular traps promote keratinocyte inflammation via AIM2 inflammasome and AIM2-XIAP in psoriasis.

The infiltration of neutrophils in the epidermis and the release of neutrophil extracellular traps (NETs) are important events in the pathogenesis of psoriasis, but the regulatory roles and internal mechanism of NETs in psoriasis are largely unknown. Here, we demonstrate that NETs can activate the absent-in-melanoma-2 (AIM2) inflammasome in keratinocytes through the p38-MAPK signalling pathway, and targeting NETs with CI-amidine in vivo reduces AIM2 expression and ameliorates imiquimod-induced psoriasis-like phenotype in mice. Notably, NETs-activated AIM2 in keratinocytes not only promotes IL-1ß production through the classical inflammasome pathway but also promotes IFN-γ production via X-linked inhibitor of apoptosis protein (XIAP), thereby mediating the immune responses of keratinocytes. In conclusion, our study demonstrates that the NETs-AIM2 axis exerts multiple pro-inflammatory effects on keratinocytes and may serve as a potential target for psoriasis therapy.

The transition path from female workers to neotenic reproductives in the termite Reticulitermes labralis.

Termite workers are characterized by unique flexibility in that a worker can develop in one of three ways: remain a worker, become a soldier within two successive moults, or become a neotenic reproductive (NR) within a single moult. However, is it true that workers can transform into NRs within a single moult? Actually, the developmental pathways of workers turning into NRs remains unclear. In this study, we show for the first time that the female workers of Reticulitermes labralis develop into NRs after a pre-NRs stage. We found that a female worker became a NR after two successive moults, whereas the male workers copulated directly with queens without undergoing any moults. After the first moult led the female workers into the pre-NR stage, the length of their abdomens, seventh sternites and ovaries significantly increased. After the second moult from the pre-NRs stage into NRs, the follicle cells returned to normal, and a few oocytes and follicle cells underwent apoptosis. These results demonstrated that the female pre-NR type was a transitional type during the development of female workers to the NR caste, and the starting point for oogenesis resumption was the NR stage. We confirmed there were fundamental differences in the reproductive pathway of the male and female workers. Therefore, we determined that the transformation process of the female NRs from workers may be a very complex process, and the reproductive biology of the workers has great potential to provide important and spectacular insights into the evolution strategy of termites.

An IGFBP7hi endothelial cell subset drives T cell extravasation in psoriasis via endothelial glycocalyx degradation.

Dysfunction of vascular endothelial cells (ECs) facilitates imbalanced immune responses and tissue hyperinflammation. However, the heterogeneous functions of skin ECs and their underlying mechanism in dermatoses remain to be determined. Here, focusing on the pathogenic role of skin ECs in psoriasis, we characterized the molecular and functional heterogeneity of skin ECs from healthy individuals and psoriasis patients at the single-cell level. We found that endothelial glycocalyx destruction, a major feature of EC dysfunction in psoriasis, was a driving force during the process of T cell extravasation. Interestingly, we identified a skin EC subset, IGFBP7hi ECs, in psoriasis. This subset actively responded to psoriatic-related cytokine signaling, secreted IGFBP7, damaged the endothelial glycocalyx, exposed the adhesion molecules underneath, and prepared the endothelium for immune-cell adhesion and transmigration, thus aggravating skin inflammation. More importantly, we provided evidence in a psoriasis-like mouse model that anti-IGFBP7 treatment showed promising therapeutic effects for restoring the endothelial glycocalyx and alleviating skin inflammation. Taken together, our results depict the distinct functions of EC clusters in healthy and psoriatic skin, identify IGFBP7hi ECs as an active subset modulating vascular function and cutaneous inflammation, and indicate that targeting IGFBP7 is a potential therapeutic strategy in psoriasis.

CD36-SREBP1 Axis Mediates TSLP Production in Obesity-Exacerbated Atopic Dermatitis.

Obesity is associated with an increased risk of atopic dermatitis (AD) and may accelerate its development. Keratinocyte dysfunction has been observed in obesity-related skin diseases, including psoriasis and acanthosis nigricans, but is not fully understood in AD. In this study, we found that high-fat diet-induced obesity exacerbated AD-like dermatitis in mice, with elevated inflammatory molecules and increased CD36-SREBP1-related fatty acid accumulation in the lesional skin. Blocking CD36 or SREBP1 with chemical inhibitors effectively alleviated AD-like inflammation, decreased fatty acid accumulation, and downregulated TSLP expression in obese calcipotriol (MC903)-treated mice. Moreover, palmitic acid treatment induced TSLP overexpression in keratinocytes through the activation of the CD36-SREBP1 signaling pathway. The chromatin immunoprecipitation assay further revealed increased binding of SREBP1 to the TSLP promoter region. Our findings provide compelling evidence that obesity triggers the activation of the CD36-SREBP1-TSLP axis in keratinocytes, leading to epidermal lipid disorders and the aggravation of AD-like inflammation. By targeting CD36 or SREBP1, future combination therapies or modified treatment strategies could be developed to help manage patients with both obesity and AD.

Keratin 17 covalently binds to alpha-enolase and exacerbates proliferation of keratinocytes in psoriasis.

Dysregulated glucose metabolism is an important characteristic of psoriasis. Cytoskeletal protein keratin 17 (K17) is highly expressed in the psoriatic epidermis and contributes to psoriasis pathogenesis. However, whether K17 is involved in the dysregulated glucose metabolism of keratinocytes (KCs) in psoriasis remains unclear. In the present study, loss- and gain-of-function studies showed that elevated K17 expression was critically involved in glycolytic pathway activation in psoriatic KCs. The level of α-enolase (ENO1), a novel potent interaction partner of K17, was also elevated in psoriatic KCs. Knockdown of ENO1 by siRNA or inhibition of ENO1 activity by the inhibitor ENOBlock remarkably suppressed KCs glycolysis and proliferation. Moreover, ENO1 directly interacted with K17 and maintained K17-Ser44 phosphorylation to promote the nuclear translocation of K17, which promoted the transcription of the key glycolysis enzyme lactic dehydrogenase A (LDHA) and resulted in enhanced KCs glycolysis and proliferation in vitro. Finally, either inhibiting the expression and activation of ENO1 or repressing K17-Ser44 phosphorylation significantly alleviated the IMQ-induced psoriasis-like phenotype in vivo. These findings provide new insights into the metabolic profile of psoriatic KCs and suggest that modulation of the ENO1-K17-LDHA axis is a potentially innovative therapeutic approach to psoriasis.

CREB1-driven CXCR4hi neutrophils promote skin inflammation in mouse models and human patients.

Neutrophils have a pathogenic function in inflammation via releasing pro-inflammatory mediators or neutrophil extracellular traps (NETs). However, their heterogeneity and pro-inflammatory mechanisms remain unclear. Here, we demonstrate that CXCR4hi neutrophils accumulate in the blood and inflamed skin in human psoriasis, and correlate with disease severity. Compared to CXCR4lo neutrophils, CXCR4hi neutrophils have enhanced NETs formation, phagocytic function, neutrophil degranulation, and overexpression of pro-inflammatory cytokines and chemokines in vitro. This is accompanied by a metabolic shift in CXCR4hi neutrophils toward glycolysis and lactate release, thereby promoting vascular permeability and remodeling. CXCR4 expression in neutrophils is dependent on CREB1, a transcription factor activated by TNF and CXCL12, and regulated by de novo synthesis. In vivo, CXCR4hi neutrophil infiltration amplifies skin inflammation, whereas blockade of CXCR4hi neutrophils through CXCR4 or CXCL12 inhibition leads to suppression of immune responses. In this work, our study identifies CREB1 as a critical regulator of CXCR4hi neutrophil development and characterizes the contribution of CXCR4hi neutrophils to vascular remodeling and inflammatory responses in skin.

CXCL12/CXCR4 Axis Drives the Chemotaxis and Differentiation of B Cells in Bullous Pemphigoid.

Bullous pemphigoid (BP) is an autoimmune bullous skin disease characterized by autoantibodies against the hemidesmosomal proteins in the skin and mucous membranes. The efficiency of B-cell‒targeting biologics in BP indicates the important role of B cells in its pathogenesis. However, abnormal B-cell migration and differentiation in BP require further elucidation. We showed that the number of antibody-secreting cells increased in the circulation and skin lesions of patients with BP and was correlated with disease severity. Bulk RNA sequencing of the peripheral B cells identified 171 upregulated and 408 downregulated genes in patients with BP compared with those in healthy controls, among which CXCR4 was significantly upregulated. Notably, CXCR4+ B cells were enriched in BP skin lesions and exhibited antibody-secreting cell characteristics. Correspondingly, an elevated level of CXCL12, the CXCR4 ligand, was detected in the blister fluid and serum of patients with BP, mediating the chemotaxis and accumulation of CXCR4+ B cells to BP skin lesions. Moreover, CXCL12 activated the transcription factor c-Myc, thus promoting B-cell differentiation into antibody-secreting cells and facilitating autoantibody production, which was blocked by CXCR4 inhibitor in vitro. Collectively, our study reveals that the CXCL12/CXCR4 axis plays a pathogenic role in modulating B-cell trafficking and differentiation, thus targeting CXCR4 represents a potential strategy for treating BP and other autoimmune diseases.

Nuclear-targeted EGF receptor enhances proliferation and migration of human anaplastic thyroid cancer cells.

INTRODUCTION: Epidermal growth factor (EGF) has various important physiological functions, which it exerts by binding to the epidermal growth factor receptor (EGFR). Reports show that EGF expression is strongly correlated with the occurrence and development of many types of tumour. To date, however, the relationship between EGF/EGFR and the occurrence and development of thyroid carcinoma remains unclear. MATERIAL AND METHODS: In the current study, we investigated this phenomenon using human anaplastic thyroid carcinoma cell lines (SUN-80). RESULTS: The results indicated that EGF triggered the EGFR-mediated intracellular signalling pathway, including signal transducers and activators of transcription 1/3/5 (STAT1/3/5) and protein kinase B (AKT) in a time- and dose-dependent manner. In addition, results from EGF-induced EGFR internalization and co-localization analyses showed that clathrin, Rab5/7, and EEA1 play critical roles in the intracellular trafficking of EGF/EGFR. Interestingly, EGF triggered EGFR translocation into the nucleus, while nuclear-localized EGFR affected cell cycle distribution, thereby significantly promoting the ration of S phase. Overall, these findings indicated that nuclear EGFR exerts biological activity and physiological functions, including changing cell cycle, which in turn promotes proliferation and migration of SUN-80 cells. CONCLUSION: These findings lay a foundation for further explorations seeking to understand the biological effects of the EGF/EGFR system on the occurrence and development of thyroid cancer.

Keratin 17 Promotes T Cell Response in Allergic Contact Dermatitis by Upregulating C-C Motif Chemokine Ligand 20.

Allergic contact dermatitis (ACD) is a delayed-type hypersensitivity response to skin contact allergens in which keratinocytes are critical in the initiation of early responses. Keratin 17 (K17) is a cytoskeletal protein inducible under stressful conditions and regulates multiple cellular processes, especially in skin inflammatory diseases; however, knowledge regarding its contribution to ACD pathogenesis remains ill defined. In the present study, we clarified the proinflammatory role of K17 in an oxazolone (OXA)-induced contact hypersensitivity (CHS) murine model and identified the underlying molecular mechanisms. Our results showed that K17 was highly expressed in the lesional skin of ACD patients and OXA-induced CHS mice. Mice lacking K17 exhibited alleviated OXA-induced skin inflammation, including milder ear swelling, a reduced frequency of T cell infiltration, and decreased inflammatory cytokine levels. In vitro, K17 stimulated and activated human keratinocytes to produce plenty of proinflammatory mediators, especially the chemokine CCL20, and promoted keratinocyte-mediated T cell trafficking. The neutralization of CCL20 with a CCL20-neutralizing monoclonal antibody significantly alleviated OXA-induced skin inflammation in vivo. Moreover, K17 could translocate into the nucleus of activated keratinocytes through a process dependent on the nuclear-localization signal (NLS) and nuclear-export signal (NES) sequences, thus facilitating the activation and nuclear translocation of signal transducer and activator of transcription 3 (STAT3), further promoting the production of CCL20 and T cell trafficking to the lesional skin. Taken together, these results highlight the novel roles of K17 in driving allergen-induced skin inflammation and suggest targeting K17 as a potential strategy for ACD.

LCN2 Mediates Skin Inflammation in Psoriasis through the SREBP2‒NLRC4 Axis.

Lipocalins are a family of secreted adipokines that regulate cell lipid metabolism and immune responses. Although we have previously revealed that LCN2 modulates neutrophil activation in psoriasis, the other roles of LCN2 in psoriatic local inflammation have remained elusive. In this study, we found that 24p3R, the well-known specific receptor of LCN2, was highly expressed in the lesional epidermis of patients with psoriasis. Silencing 24p3R (also known as slc22a17) alleviated hyperkeratosis, inflammatory cell infiltration, and overexpression of inflammatory mediators in an imiquimod-induced psoriasis-like mouse model. In vitro, LCN2 enhanced the expression of proinflammatory factors in primary keratinocytes, such as IL-1ß, IL-23, CXCL1, and CXCL10, which was paralleled by enforced cholesterol biosynthetic signaling. Importantly, taking in vivo and in vitro approaches, we discovered the SREBP2, a vital transcriptional factor in cholesterol synthesis pathway, as the critical mediator of LCN2-induced keratinocyte activation, which bound to the promoter region of NLRC4. Suppressing SREBP2 in mice attenuated NLRC4 signaling and psoriasis-like dermatitis. Taken together, this study identifies the critical role of LCN2‒SREBP2‒NLRC4 axis in the pathogenesis of psoriasis and proposes 24p3R or SREBP2 as a potential therapeutic target for psoriasis.

Quinolinic Acid, a Tryptophan Metabolite of the Skin Microbiota, Negatively Regulates NLRP3 Inflammasome through AhR in Psoriasis.

Psoriasis is a chronic inflammatory skin disease whose pathogenesis involves skin microbiota dysbiosis. Multiple studies have revealed the changes in microbiota abundances between psoriatic lesions and healthy skin. However, the metabolic pathways of skin microbiota (especially tryptophan metabolism, which is closely related to immunosuppression) are far less understood. In this study, we first detected the major microbial metabolites of tryptophan on the skin surfaces, finding that the quinolinic acid was significantly lower in the lesional skin of patients with psoriasis than in that of healthy subjects and correlated negatively with the severity of psoriasis. In vitro and in vivo, applying quinolinic acid significantly alleviated skin inflammation in an AhR-dependent manner, resulting in inhibition of the NLRP3 inflammasome activation. Furthermore, in mice with imiquimod-induced psoriasis-like dermatitis, topical application of Ahr-targeted small interfering RNA substantially exacerbated the disease severity, with increased NLRP3 inflammasome activation. Collectively, our data suggest that quinolinic acid, a skin microbiota-derived metabolite, negatively regulates aryl hydrocarbon receptor-NLRP3 inflammasome signaling activation in patients with psoriasis, providing an insight into the correlation between microbiota metabolism and the host skin in individuals with psoriasis.

Synthesis and anti-inflammatory activity of novel steroidal chalcones with 3ß-pregnenolone ester derivatives in RAW 264.7 cells in vitro.

To identify new potential anti-inflammatory agents, we herein report the synthesis of novel steroidal chalcones with 3ß-pregnenolone esters of cinnamic acid derivatives using pregnenolone as the starting material. The structures of the newly synthesised compounds were confirmed by 1H NMR, 13C NMR, HRMS and infrared imaging. All the derivatives were examined to determine their in vitro anti-inflammatory profiles against LPS-induced inflammation in RAW 264.7 cells; the derivates were evaluated by the quantification of the pro-inflammatory mediator nitric oxide (NO) in the cell culture supernatant based on the Griess reaction, which measures nitrite levels, followed by an in vitro cytotoxicity study. Among these novel derivatives, compound 11e [3ß-3-phenyl acrylate-pregn-5-en-17ß-yl-3' -(p-fluoro)-phenylprop-2'-en-1'-one] was identified as the most potent anti-inflammatory agent, which showed significant anti-inflammatory activity by inhibiting the LPS-induced pro-inflammatory mediator NO in a dose-dependent manner without any cytotoxicity. Moreover, compound 11e markedly inhibited the expression of pro-inflammatory cytokines, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α), and cyclooxygenase-2 (COX-2), in LPS-induced RAW 264.7 cells. Further studies confirmed that compound 11e significantly suppressed the transcriptional activity of NF-κB in activated RAW 264.7 cells. Molecular docking study revealed the strong binding affinity of compound 11e to the active site of the pro-inflammatory proteins, which confirmed that compound 11e acted as an anti-inflammatory mediator. These results indicated that steroidal chalcones with 3ß-pregnenolone esters of cinnamic acid derivatives might be considered for further research in the design of anti-inflammatory drugs, and compound 11e might be a promising therapeutic anti-inflammatory drug candidate.

Cyclin-Dependent Kinase 7 Promotes Th17/Th1 Cell Differentiation in Psoriasis by Modulating Glycolytic Metabolism.

Excessive activation of CD4+ T cells and T helper type (Th) 17/Th1 cell differentiation are critical events in psoriasis pathogenesis, but the associated molecular mechanism is still unclear. Here, using quantitative proteomics analysis, we found that cyclin-dependent kinase 7 (CDK7) expression was markedly increased in CD4+ T cells from patients with psoriasis compared with healthy controls and was positively correlated with psoriasis severity. Meanwhile, genetic or pharmacological inhibition of CDK7 ameliorated the severity of psoriasis in the imiquimod-induced psoriasis-like mouse model and suppressed CD4+ T-cell activation as well as Th17/Th1 cell differentiation in vivo and in vitro. Furthermore, the CDK7 inhibitor also reduced the enhanced glycolysis of CD4+ T cells from patients with psoriasis. Proinflammatory cytokine IL-23 induced increased CDK7 expression in CD4+ T cells and activated the protein kinase B/mTOR/HIF-1α signaling pathway, enhancing glycolytic metabolism. Correspondingly, CDK7 inhibition significantly impaired IL-23-induced glycolysis via the protein kinase B/mTOR/HIF-1α pathway. In summary, this study shows that CDK7 promotes CD4+ T-cell activation and Th17/Th1 cell differentiation by regulating glycolysis, thus contributing to the pathogenesis of psoriasis. Targeting CDK7 might be a promising immunosuppressive strategy to control skin inflammation mediated by IL-23.

Neutrophils Enhance Cutaneous Vascular Dilation and Permeability to Aggravate Psoriasis by Releasing Matrix Metallopeptidase 9.

Neutrophil infiltration and papillary vessel dilation are hallmarks of the initiation phase of psoriatic lesions. However, how neutrophils aggravate psoriasis development during transendothelial migration and the interaction between neutrophils and cutaneous vascular endothelial cells are less well-understood. In this study, we reported that neutrophils and cutaneous vascular endothelial cells activated each other when neutrophils migrated through the cutaneous endothelial barrier. In addition, neutrophil infiltration into skin lesions caused vascular remodeling including cutaneous vasodilation and enhanced vascular permeability in vivo and in vitro. Microarray gene profile data showed that matrix metallopeptidase (MMP)-9 was overexpressed in psoriatic neutrophils, and zymography assay further validated the bioactivity of MMP-9 secreted by psoriatic neutrophils. Moreover, MMP-9 activated vascular endothelial cells through the extracellular signal‒regulated kinase 1/2 and p38-MAPK signaling pathways, enhancing CD4+ T-cell transmigration in vitro. Correspondingly, an MMP-9 inhibitor significantly reduced cutaneous vasodilation, vascular permeability, and psoriatic symptoms in an imiquimod- or IL-23‒induced psoriasiform mouse model. Overall, our study demonstrates that neutrophil-derived MMP-9 induces cutaneous vasodilation and hyperpermeability by activating cutaneous vascular endothelial cells, thus facilitating psoriatic lesion development, which increases our knowledge on the role of neutrophils in the pathogenesis of psoriasis.