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Background and Aims: Survival rates for esophageal squamous cell carcinoma (ESCC) are extremely low due to the late diagnosis of most cases. An understanding of the early molecular processes that lead to ESCC may facilitate opportunities for early diagnosis; however, these remain poorly defined. Tylosis with esophageal cancer (TOC) is a rare syndrome associated with a high lifetime risk of ESCC and germline mutations in RHBDF2, encoding iRhom2. Using TOC as a model of ESCC predisposition, this study aimed to identify early-stage transcriptional changes in ESCC development. Methods: Esophageal biopsies were obtained from control and TOC individuals, the latter undergoing surveillance endoscopy, and adjacent diagnostic biopsies were graded as having no dysplasia or malignancy. Bulk RNA-Seq was performed, and findings were compared with sporadic ESCC vs normal RNA-Seq datasets. Results: Multiple transcriptional changes were identified in TOC samples, relative to controls, and many were detected in ESCC. Accordingly, pathway analyses predicted an enrichment of cancer-associated processes linked to cellular proliferation and metastasis, and several transcription factors were predicted to be associated with TOC and ESCC, including negative enrichment of GRHL2. Subsequently, a filtering strategy revealed 22 genes that were significantly dysregulated in both TOC and ESCC. Moreover, Keratin 17, which was upregulated in TOC and ESCC, was also found to be overexpressed at the protein level in 'normal' TOC esophagus tissue. Conclusion: Transcriptional changes occur in TOC esophagus prior to the onset of dysplasia, many of which are associated with ESCC. These findings support the utility of TOC to help reveal the early molecular processes that lead to sporadic ESCC.
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iRhoms are pseudoprotease members of the rhomboid-like superfamily and are cardinal regulators of inflammatory and growth factor signaling; they function primarily by recognizing transmembrane domains of their clients. Here, we report a mechanistically distinct nuclear function of iRhoms, showing that both human and mouse iRhom2 are non-canonical substrates of signal peptidase complex (SPC), the protease that removes signal peptides from secreted proteins. Cleavage of iRhom2 generates an N-terminal fragment that enters the nucleus and modifies the transcriptome, in part by binding C-terminal binding proteins (CtBPs). The biological significance of nuclear iRhom2 is indicated by elevated levels in skin biopsies of patients with psoriasis, tylosis with oesophageal cancer (TOC), and non-epidermolytic palmoplantar keratoderma (NEPPK); increased iRhom2 cleavage in a keratinocyte model of psoriasis; and nuclear iRhom2 promoting proliferation of keratinocytes. Overall, this work identifies an unexpected SPC-dependent ER-to-nucleus signaling pathway and demonstrates that iRhoms can mediate nuclear signaling.
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Psoríase , Transdução de Sinais , Animais , Humanos , Camundongos , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Psoríase/genética , Serina Endopeptidases/genética , Serina Endopeptidases/metabolismoRESUMO
Pachyonychia congenita (PC) is a dominantly inherited genetic disorder of cornification. PC stands out among other genodermatoses because despite its rarity, it has been the focus of a very large number of pioneering translational research efforts over the past 2 decades, mostly driven by a patient support organization, the Pachyonychia Congenita Project. These efforts have laid the ground for innovative strategies that may broadly impact approaches to the management of other inherited cutaneous and noncutaneous diseases. This article outlines current avenues of research in PC, expected outcomes, and potential hurdles.
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Ceratodermia Palmar e Plantar , Paquioníquia Congênita , Humanos , Paquioníquia Congênita/diagnóstico , Paquioníquia Congênita/genética , Paquioníquia Congênita/terapia , Ceratodermia Palmar e Plantar/genética , Administração Cutânea , Apoptose , Diferenciação Celular , MutaçãoRESUMO
Introduction: Heartburn pathogenesis in GERD remains incompletely understood. We aimed to identify differences in the immune cell signature and sensory mucosal markers between reflux phenotypes and healthy asymptomatic subjects. Methods: Thirty-seven patients with heartburn symptoms were phenotyped endoscopically and with objective reflux studies into erosive reflux disease (ERD) (N=10), nonerosive reflux disease (NERD) (N=9), functional heartburn (FH) (N=9), and Barrett's esophagus (BO) (N=9). Bulk mRNA-sequencing(RNA-seq) was conducted on RNA extracted from endoscopic biopsies, and immune cell deconvolution analysis was performed using CIBERSORT. RNA-seq findings were validated by immunofluorescent staining for CD1a, nerve growth factor (NGF), and mast cell tryptase in corresponding patient biopsies. Results: Transcriptomic analysis detected higher mast cell abundance in BO, ERD, and NERD compared to healthy controls (p<0.05), with decreased dendritic cell infiltration in BO, ERD, and NERD patients compared to healthy controls and FH patients. CD1a-positive dendritic cell infiltration was significantly higher in the healthy esophageal mucosa at protein level compared to BO (p=0.0005), ERD (p=0.0004), and FH patients (p=0.0096). Moreover, NGF co-expression on mast cells in GERD patients was significantly higher than in healthy controls (p=0.0094). Discussion: The mucosa in patients with GERD had a significant increase in NGF expression on mast cells, suggesting an upregulation of signalling for neuronal sprouting in GERD. Moreover, decreased dendritic cell abundance in GERD esophageal mucosa may play a role in reduced oral tolerance and development of subsequent immune responses which may participate in esophageal sensitivity.
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Refluxo Gastroesofágico , Azia , Humanos , Azia/diagnóstico , Azia/patologia , Mastócitos/patologia , Fator de Crescimento Neural , Refluxo Gastroesofágico/diagnóstico , Refluxo Gastroesofágico/patologia , Mucosa/patologia , Células Dendríticas/patologiaRESUMO
BACKGROUND: Hyperlinear palms are described as a feature of loss-of-function (LoF) variants in filaggrin (FLG). OBJECTIVES: To explore the phenotype of participants (age < 31â years) with atopic eczema of Bangladeshi ancestry from East London and investigate which factors best associate with LoF FLG variants. METHODS: A cross-sectional study with participants recruited between May 2018 and December 2020. Patterns of palmar linearity were categorized and modelled with the Eczema Area and Severity Index (EASI), transepidermal water loss (TEWL), skin hydration (SH) and LoF FLG variants. RESULTS: There were 506 complete cases available. Five palm patterns were noted. The 'prominent diamond' pattern associated best with EASI [marginal effects (ME) 2.53, 95% confidence interval (CI) 1.74-3.67], SH (ME 0.85, 95% CI 0.78-0.96) and TEWL (ME 1.32, 95% CI 1.11-1.62). Using five palm patterns had some ability to discriminate LoF FLG variants [area under the receiver operator characteristic (AUROC) 76.32%, 95% CI 71.91-80.73], improving to 77.99% (73.70-82.28) with the addition of SH. In subgroup analysis with only fine perpendicular/prominent diamond patterns the AUROC was 89.11% (95% CI 84.02-94.19). CONCLUSIONS: This was a single-centre study design with humans classifying clinical patterns. The stability of temperature and humidity was not guaranteed across TEWL and SH measurements despite using a climate-controlled room. Palm patterns associate with EASI and TEWL. The fine perpendicular/prominent diamond patterns are markers to detect the absence/presence of LoF FLG variants, respectively.
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Dermatite Atópica , Eczema , Humanos , Adulto , Dermatite Atópica/genética , Proteínas Filagrinas , Estudos Transversais , Eczema/genética , Gravidade do Paciente , Proteínas de Filamentos Intermediários/genética , Proteínas de Filamentos Intermediários/metabolismo , Mutação/genética , Predisposição Genética para Doença/genéticaRESUMO
BACKGROUND: Atopic eczema (AE) is a chronic relapsing, pruritic disease that greatly affects the child and family's quality of life (QoL). It is usually common and severe among children of Bangladeshi ethnicity. OBJECTIVES: This is a cross-sectional quantitative study in patients with AE of Bangladeshi origin, which aims to analyse different components of the family, children and adult quality-of-life indices and their relationship to patient age, sex, eczema severity and distribution, other allergic associations, parental education and socioeconomic level. METHODS: Children and young adults of Bangladeshi origin aged 0-30â years, clinically diagnosed with AE were recruited as part of the Tower Hamlets Eczema Assessment project, a clinical phenotyping study of AE in the Bangladeshi population living in East London. Questionnaires completed by children/parents included the Family Dermatology Life Quality Index (FDLQI), Infant's Dermatology Quality of Life (IDQOL) and the Children's Dermatology Life Quality Index (CDLQI). Young adults completed the Dermatology Life Quality Index (DLQI). The disease severity was assessed objectively using the Eczema Area Severity Index (EASI). Patients and parents who did not read or speak English were aided by Bengali/Sylheti-speaking research assistants. RESULTS: Overall, 460 Bangladeshi children and 98 adults with AE were recruited. Burden of care, extra housework and emotional distress were the highest affected domains in parental QoL, while itching and sleep were the highest for children. Significant factors influencing FDLQI score were EASI [marginal effect (ME) 1.01, 95% confidence interval (CI) 1.00-1.03; P = 0.004], age (ME 0.98, 95% CI 0.97-0.99; P = 0.004), extensor eczema distribution (ME 1.25, 95% CI 1.03-1.52; P = 0.023), parental English fluency (ME 1.29, 95% CI 1.10-1.52; P = 0.002) and atopic comorbidities (ME 1.10, 95% CI 1.04-1.17; P = 0.001). Parental socioeconomic class was a nonsignificant factor. IDQOL/CDLQI was influenced significantly by the child's age (ME 0.99, 95% CI 0.97-1.00, P = 0.023), 'nonclear' eczema distribution clusters especially the 'severe extensive' cluster (ME 1.46, 95% CI 1.15-1.84; P = 0.002) and nonsignificantly by EASI and parental English literacy and socioeconomic levels. DLQI was affected significantly by nonclear eczema distribution groups especially 'severe extensive' (ME 2.49, 95% 1.76-3.53; P < 0.001) and nonsignificantly by patient age, and female sex. CONCLUSIONS: AE is a chronic disease where many external factors other than disease severity affect QoL of patients and their families, -especially in under-represented minority groups who face different linguistic and cultural barriers.
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Dermatite Atópica , Dermatologia , Eczema , Criança , Lactente , Adulto Jovem , Humanos , Feminino , Dermatite Atópica/psicologia , Qualidade de Vida , Estudos Transversais , Londres/epidemiologia , Índice de Gravidade de Doença , PruridoRESUMO
Atopic eczema is a common and complex disease. Missing genetic hereditability and increasing prevalence in industrializing nations point toward an environmental driver. We investigated the temporal association of weather and pollution parameters with eczema severity. This cross-sectional clinical study was performed between May 2018 and March 2020 and is part of the Tower Hamlets Eczema Assessment. All participants had a diagnosis of eczema, lived in East London, were of Bangladeshi ethnicity, and were aged <31 years. The primary outcome was the probability of having an Eczema Area and Severity Index score > 10 after previous ambient exposure to commonly studied meteorological variables and pollutants. There were 430 participants in the groups with Eczema Area and Severity Index ≤ 10 and 149 in those with Eczema Area and Severity Index > 10. Using logistic generalized additive models and a model selection process, we found that tropospheric ozone averaged over the preceding 270 days was strongly associated with eczema severity alongside the exposure to fine particles with diameters of 2.5 µm or less (fine particulate matter) averaged over the preceding 120 days. In our models and analyses, fine particulate matter appeared to largely act in a supporting role to ozone. We show that long-term exposure to ground-level ozone at high levels has the strongest association with eczema severity.
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The palmoplantar epidermis is a specialized area of the skin that undergoes high levels of mechanical stress. The palmoplantar keratinization and esophageal cancer syndrome, tylosis with esophageal cancer, is linked to mutations in RHBDF2 encoding the proteolytically inactive rhomboid protein, iRhom2. Subsequently, iRhom2 was found to affect palmoplantar thickening to modulate the stress keratin response and to mediate context-dependent stress pathways by p63. iRhom2 is also a direct regulator of the sheddase, ADAM17, and the antiviral adaptor protein, stimulator of IFN genes. In this perspective, the pleiotropic functions of iRhom2 are discussed with respect to the skin, inflammation, and the antiviral response.
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Dermatite/imunologia , Epiderme/patologia , Neoplasias Esofágicas/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Ceratodermia Palmar e Plantar/genética , Dermatopatias Virais/imunologia , Proteína ADAM17/metabolismo , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Dermatite/genética , Modelos Animais de Doenças , Epiderme/imunologia , Neoplasias Esofágicas/imunologia , Neoplasias Esofágicas/patologia , Pé , Regulação da Expressão Gênica/imunologia , Mãos , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/imunologia , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Queratinócitos/imunologia , Queratinócitos/metabolismo , Queratinas/metabolismo , Ceratodermia Palmar e Plantar/imunologia , Ceratodermia Palmar e Plantar/patologia , Camundongos , Camundongos Knockout , Mutação , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Dermatopatias Virais/genética , Dermatopatias Virais/virologia , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismoAssuntos
Pesquisa Biomédica/tendências , Dermatologia/tendências , Previsões , Sociedades Científicas/tendências , Inteligência Artificial/tendências , Pesquisa Biomédica/história , Dermatologia/história , Europa (Continente) , História do Século XX , História do Século XXI , Sociedades Científicas/históriaRESUMO
The biology of harlequin ichthyosis (HI), a devastating skin disorder caused by loss-of-function mutations in the gene ABCA12, is poorly understood, and to date, no satisfactory treatment has been developed. We sought to investigate pathomechanisms of HI that could lead to the identification of new treatments for improving patients' quality of life. In this study, RNA-Seq and functional assays were performed to define the effects of loss of ABCA12 using HI patient skin samples and an engineered CRISPR/Cas9 ABCA12 KO cell line. The HI living skin equivalent (3D model) recapitulated the HI skin phenotype. The cytokines IL-36α and IL-36γ were upregulated in HI skin, whereas the innate immune inhibitor IL-37 was strongly downregulated. We also identified STAT1 and its downstream target inducible nitric oxide synthase (NOS2) as being upregulated in the in vitro HI 3D model and HI patient skin samples. Inhibition of NOS2 using the inhibitor 1400W or the JAK inhibitor tofacitinib dramatically improved the in vitro HI phenotype by restoring the lipid barrier in the HI 3D model. Our study has identified dysregulated pathways in HI skin that are feasible therapeutic targets.
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Amidinas/farmacologia , Benzilaminas/farmacologia , Sistemas de Liberação de Medicamentos , Ictiose Lamelar , Modelos Biológicos , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Piperidinas/farmacologia , Pirimidinas/farmacologia , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Técnicas de Cultura de Células , Células Cultivadas , Técnicas de Silenciamento de Genes , Humanos , Ictiose Lamelar/tratamento farmacológico , Ictiose Lamelar/genética , Ictiose Lamelar/metabolismo , Ictiose Lamelar/patologia , Inflamação/tratamento farmacológico , Inflamação/genética , Inflamação/metabolismo , Inflamação/patologia , Interleucina-1/genética , Interleucina-1/metabolismo , Mutação com Perda de Função , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/metabolismoAssuntos
Dermatite Atópica/epidemiologia , Etnicidade , Genótipo , Proteínas de Filamentos Intermediários/genética , Mutação/genética , Bangladesh , Dermatite Atópica/genética , Proteínas Filagrinas , Frequência do Gene , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Imunoglobulina E/metabolismo , Linhagem , Fenótipo , Polimorfismo Genético , Risco , Reino Unido/epidemiologia , Reino Unido/etnologia , Sequenciamento do ExomaRESUMO
Hyperproliferative keratinocytes induced by trauma, hyperkeratosis and/or inflammation display molecular signatures similar to those of palmoplantar epidermis. Inherited gain-of-function mutations in RHBDF2 (encoding iRHOM2) are associated with a hyperproliferative palmoplantar keratoderma and squamous oesophageal cancer syndrome (termed TOC). In contrast, genetic ablation of rhbdf2 in mice leads to a thinning of the mammalian footpad, and reduces keratinocyte hyperproliferation and migration. Here, we report that iRHOM2 is a novel target gene of p63 and that both p63 and iRHOM2 differentially regulate cellular stress-associated signalling pathways in normal and hyperproliferative keratinocytes. We demonstrate that p63-iRHOM2 regulates cell survival and response to oxidative stress via modulation of SURVIVIN and Cytoglobin, respectively. Furthermore, the antioxidant compound Sulforaphane downregulates p63-iRHOM2 expression, leading to reduced proliferation, inflammation, survival and ROS production. These findings elucidate a novel p63-associated pathway that identifies iRHOM2 modulation as a potential therapeutic target to treat hyperproliferative skin disease and neoplasia.
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Proteínas de Transporte/metabolismo , Proliferação de Células/genética , Carcinoma de Células Escamosas do Esôfago/patologia , Queratinócitos/metabolismo , Estresse Oxidativo/genética , Fosfoproteínas/metabolismo , Transativadores/metabolismo , Animais , Apoptose/genética , Proteínas de Transporte/genética , Linhagem Celular , Sobrevivência Celular/genética , Citoglobina/biossíntese , Feminino , Células HEK293 , Humanos , Isotiocianatos/farmacologia , Camundongos , Camundongos Knockout , Fosfoproteínas/genética , Interferência de RNA , RNA Interferente Pequeno/genética , Espécies Reativas de Oxigênio/metabolismo , Dermatopatias/patologia , Sulfóxidos , Survivina/biossíntese , Transativadores/genéticaRESUMO
Small-molecule inhibitors of the Hedgehog (HH) pathway receptor Smoothened (SMO) have been effective in treating some patients with basal cell carcinoma (BCC), where the HH pathway is often activated, but many patients respond poorly. In this study, we report the results of investigations on PTCH1 signaling in the HH pathway that suggest why most patients with BCC respond poorly to SMO inhibitors. In immortalized human keratinocytes, PTCH1 silencing led to the generation of a compact, holoclone-like morphology with increased expression of SMO and the downstream HH pathway transcription factor GLI1. Notably, although siRNA silencing of SMO in PTCH1-silenced cells was sufficient to suppress GLI1 activity, this effect was not phenocopied by pharmacologic inhibition of SMO, suggesting the presence of a second undefined pathway through which SMO can induce GLI1. Consistent with this possibility, we observed increased nuclear localization of SMO in PTCH1-silenced cells as mediated by a putative SMO nuclear/nucleolar localization signal [N(o)LS]. Mutational inactivation of the N(o)LS ablated this increase and suppressed GLI1 induction. Immunohistologic analysis of human and mouse BCC confirmed evidence of nuclear SMO, although the pattern was heterogeneous between tumors. In PTCH1-silenced cells, >80% of the genes found to be differentially expressed were unaffected by SMO inhibitors, including the putative BCC driver gene CXCL11. Our results demonstrate how PTCH1 loss results in aberrant regulation of SMO-independent mechanisms important for BCC biology and highlights a novel nuclear mechanism of SMO-GLI1 signaling that is unresponsive to SMO inhibitors.Significance: This study describes novel noncanonical Hedgehog signaling, where SMO enters the nucleus to activate GLI1, a mode that is unaffected by SMO inhibitors, thus prompting re-evaluation of current BCC treatment as well as new potential therapies targeting nuclear SMO. Cancer Res; 78(10); 2577-88. ©2018 AACR.
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Carcinoma Basocelular/patologia , Receptor Patched-1/metabolismo , Neoplasias Cutâneas/patologia , Receptor Smoothened/metabolismo , Proteína GLI1 em Dedos de Zinco/metabolismo , Linhagem Celular Tumoral , Quimiocina CXCL11/genética , Humanos , Queratinócitos/patologia , Receptor Patched-1/genética , Interferência de RNA , RNA Interferente Pequeno/genética , Receptor Smoothened/antagonistas & inibidores , Receptor Smoothened/genéticaRESUMO
In a tissue continuously challenged by mechanical stresses, such as the skin or the heart, cells perceive information about their microenvironment through several adhesive protein complexes and activate cell-signaling events to maintain tissue cohesion. Consequently, alteration of cell adhesion components leads to aberrant assembly of the associated cytoplasmic scaffolding and signaling pathways, which may reflect changes to the tissue physiology and mechanical resistance. Desmoplakin is an essential component of the cell-cell junction, anchoring the desmosomal protein complex to the intermediate filaments (IFs). Inherited mutations in desmoplakin are associated with both heart and skin disease (cardiocutaneous syndrome). In this study, we investigated the mechanical properties of human keratinocytes harboring a cardiocutaneous-associated homozygous C-terminal truncation in desmoplakin (JD-1) compared to a control keratinocyte line (K1). Using Single Cell Force Spectroscopy (SCFS) AFM-based measurements, JD-1 keratinocytes displayed an overall alteration in morphology, elasticity, adhesion capabilities and viscoelastic properties, highlighting the profound interconnection between the adhesome pathways and the IF scaffold.
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Adesão Celular/fisiologia , Desmoplaquinas/genética , Elasticidade/fisiologia , Filamentos Intermediários/fisiologia , Queratinócitos/metabolismo , Fenômenos Fisiológicos da Pele/genética , Adesão Celular/genética , Células Cultivadas , Humanos , Junções Intercelulares/fisiologia , Microscopia de Força Atômica , Análise de Célula Única/métodos , Pele/citologia , Pele/metabolismoAssuntos
DNA/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Ceratodermia Palmar e Plantar/genética , Mutação , Adulto , Biópsia , Análise Mutacional de DNA , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ceratodermia Palmar e Plantar/diagnóstico , Ceratodermia Palmar e Plantar/metabolismo , Linhagem , Couro Cabeludo , Pele/metabolismo , Pele/patologiaRESUMO
Mutations in ceramide biosynthesis pathways have been implicated in a few Mendelian disorders of keratinization, although ceramides are known to have key roles in several biological processes in skin and other tissues. Using whole-exome sequencing in four probands with undiagnosed skin hyperkeratosis/ichthyosis, we identified compound heterozygosity for mutations in KDSR, encoding an enzyme in the de novo synthesis pathway of ceramides. Two individuals had hyperkeratosis confined to palms, soles, and anogenital skin, whereas the other two had more severe, generalized harlequin ichthyosis-like skin. Thrombocytopenia was present in all patients. The mutations in KDSR were associated with reduced ceramide levels in skin and impaired platelet function. KDSR enzymatic activity was variably reduced in all patients, resulting in defective acylceramide synthesis. Mutations in KDSR have recently been reported in inherited recessive forms of progressive symmetric erythrokeratoderma, but our study shows that biallelic mutations in KDSR are implicated in an extended spectrum of disorders of keratinization in which thrombocytopenia is also part of the phenotype. Mutations in KDSR cause defective ceramide biosynthesis, underscoring the importance of ceramide and sphingosine synthesis pathways in skin and platelet biology.
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Oxirredutases do Álcool/genética , Ceramidas/biossíntese , Predisposição Genética para Doença , Ceratodermia Palmar e Plantar/complicações , Ceratodermia Palmar e Plantar/genética , Trombocitopenia/complicações , Adolescente , Alelos , Biópsia por Agulha , Criança , Humanos , Imuno-Histoquímica , Técnicas In Vitro , Ceratodermia Palmar e Plantar/patologia , Masculino , Mutação , Linhagem , Prognóstico , Estudos de Amostragem , Índice de Gravidade de Doença , Trombocitopenia/diagnóstico , Adulto JovemRESUMO
Keratin 16 (K16) is a cytoskeletal scaffolding protein highly expressed at pressure-bearing sites of the mammalian footpad. It can be induced in hyperproliferative states such as wound healing, inflammation and cancer. Here we show that the inactive rhomboid protease RHBDF2 (iRHOM2) regulates thickening of the footpad epidermis through its interaction with K16. K16 expression is absent in the thinned footpads of irhom2-/- mice compared with irhom2+/+mice, due to reduced keratinocyte proliferation. Gain-of-function mutations in iRHOM2 underlie Tylosis with oesophageal cancer (TOC), characterized by palmoplantar thickening, upregulate K16 with robust downregulation of its type II keratin binding partner, K6. By orchestrating the remodelling and turnover of K16, and uncoupling it from K6, iRHOM2 regulates the epithelial response to physical stress. These findings contribute to our understanding of the molecular mechanisms underlying hyperproliferation of the palmoplantar epidermis in both physiological and disease states, and how this 'stress' keratin is regulated.
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Proteínas de Transporte/metabolismo , Epiderme/fisiologia , Queratina-16/metabolismo , Animais , Proteínas de Transporte/genética , Linhagem Celular , Proliferação de Células/fisiologia , Citoesqueleto/fisiologia , Regulação para Baixo , Células Epidérmicas , Neoplasias Esofágicas/genética , Neoplasias Esofágicas/patologia , Feminino , Fibroblastos , Mutação com Ganho de Função , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Queratina-6/metabolismo , Queratinócitos/fisiologia , Ceratodermia Palmar e Plantar/genética , Ceratodermia Palmar e Plantar/patologia , Masculino , Camundongos , Camundongos Knockout , Pressão , RNA Interferente Pequeno/metabolismo , Estresse Fisiológico/fisiologia , Técnicas de Cultura de Tecidos , Regulação para Cima , Cicatrização/fisiologiaRESUMO
The vitally important skin barrier is formed by extensive cross-linking activity of transglutaminases (TGs) during terminal epidermal differentiation. We have previously shown that epidermal deficiency of a disintegrin and metalloproteinase 17 (ADAM17), the principal EGFR ligand sheddase, results in postnatal skin barrier defects in mice due to impeded TG activity. However, the mechanism by which ADAM17/EGFR signalling maintains TG activity during epidermal differentiation remains elusive. Here we demonstrate that ADAM17-dependent EGFR signalling promotes TG activity in keratinocytes committed to terminal differentiation by direct induction of TG1 expression. Restored TG1 expression of EGF-stimulated differentiated Adam17-/- keratinocytes was strongly repressed by inhibitors for PLCγ1 or protein kinase C (PKC) pathways, while treatment with the PKC stimulator 12-O-tetradecanoylphorbol-13-acetate restored TG activity in the epidermis of keratinocyte-specific Adam17-/- (AD17ΔKC) mice. Further investigations emphasized the expression of PKCη, a mediator of TGM1 transcription, to be sensitive to EGFR activation. In agreement, topical skin application of cholesterol sulfate, an activator of PKCη, significantly improved TG activity in epidermis of AD17ΔKC mice. Our results suggest ADAM17/EGFR-driven PLCγ1 and PKC pathways as important promoters of TG1 expression during terminal keratinocyte differentiation. These findings may help to identify new therapeutic targets for inflammatory skin diseases related to epidermal barrier defects.