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BACKGROUND: Lung adenocarcinoma (LUAD) is a highly aggressive and rapidly fatal malignancy worldwide. Collagen XVII (COL17A1) has been implicated in various protumorigenic processes. However, the functions and mechanisms of COL17A1 in LUAD progression still remain elusive. METHODS: COL17A1 and ubiquitin-specific protease 22 (USP22) mRNA analysis was performed by quantitative PCR, and their protein levels were detected by immunoblotting and immunohistochemistry. The functional influence was evaluated by determining cell viability, proliferation, apoptosis, invasion, migration, and ferroptosis in vitro, as well as xenograft growth in vivo. Co-immunoprecipitation (Co-IP) and IP experiments were used to examine the USP22/COL17A1 interaction and COL17A1 deubiquitination. Cycloheximide treatment was used to analyze COL17A1 protein stability. RESULTS: COL17A1 and USP22 were upregulated in human LUAD tissues and cell lines. Functionally, COL17A1 knockdown acted for the suppression of LUAD cell growth, invasion, and migration as well as promotion of cell apoptosis and ferroptosis in vitro. COL17A1 knockdown could diminish the tumorigenicity of LUAD cells in vivo. Mechanistically, USP22 stabilized and upregulated COL17A1 by enhancing the deubiquitination of COL17A1. Additionally, reexpression of COL17A1 could reverse USP22 silencing-induced phenotype changes of LUAD cells in vitro. CONCLUSION: Our findings demonstrate that USP22-stabilized COL17A1 possesses oncogenic activity in LUAD. We propose that USP22 and COL17A1 would be potential targets for the establishment of therapeutic approaches against LUAD.
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Adenocarcinoma de Pulmão , Proliferação de Células , Progressão da Doença , Neoplasias Pulmonares , Ubiquitina Tiolesterase , Humanos , Ubiquitina Tiolesterase/metabolismo , Ubiquitina Tiolesterase/genética , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/metabolismo , Camundongos , Proliferação de Células/genética , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma de Pulmão/metabolismo , Animais , Linhagem Celular Tumoral , Apoptose/genética , Masculino , Feminino , Regulação Neoplásica da Expressão Gênica , Movimento Celular/genética , UbiquitinaçãoRESUMO
Tumor dormancy is the underpinning for cancer relapse and chemoresistance, leading to massive cancer-related death in colorectal cancer (CRC). However, our comprehension of the mechanisms dictating tumor dormancy and strategies for eliminating dormant tumor cells remains restricted. In this study, we identified that collagen XVII (COL17A1), a hemidesmosomal transmembrane protein, can promote the dormancy of CRC cells. The upregulation of COL17A1 was observed to prolong quiescence periods and diminish drug susceptibility of CRC cells. Mechanistically, COL17A1 acts as a scaffold, enhancing the crosstalk between mTORC2 and Akt, thereby instigating the mTORC2-mediated dormant signaling. Notably, the activation of mTORC2 is contingent upon the intracellular domain of COL17A1, regardless of its ectodomain shedding. Our findings underscore a pivotal role of the COL17A1-mTORC2 axis in CRC dormancy, suggesting that mTORC2-specific inhibitors may hold therapeutic prospects for the eradication of dormant tumor cells.
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Colágeno Tipo XVII , Neoplasias Colorretais , Alvo Mecanístico do Complexo 2 de Rapamicina , Colágenos não Fibrilares , Transdução de Sinais , Humanos , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Neoplasias Colorretais/genética , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Colágenos não Fibrilares/metabolismo , Colágenos não Fibrilares/genética , Linhagem Celular Tumoral , Animais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Autoantígenos/metabolismo , Camundongos , Camundongos Nus , Proliferação de Células , Camundongos Endogâmicos BALB CRESUMO
Deficiency of DNA repair pathways drives the development of colorectal cancer. However, the role of the base excision repair (BER) pathway in colorectal cancer initiation remains unclear. This study shows that Nei-like DNA glycosylase 1 (NEIL1) is highly expressed in colorectal cancer (CRC) tissues and associated with poorer clinical outcomes. Knocking out neil1 in mice markedly suppresses tumorigenesis and enhances infiltration of CD8+ T cells in intestinal tumors. Furthermore, NEIL1 directly forms a complex with SATB2/c-Myc to enhance the transcription of COL17A1 and subsequently promotes the production of immunosuppressive cytokines in CRC cells. A NEIL1 peptide suppresses intestinal tumorigenesis in ApcMin/+ mice, and targeting NEIL1 demonstrates a synergistic suppressive effect on tumor growth when combined with a nuclear factor κB (NF-κB) inhibitor. These results suggest that combined targeting of NEIL1 and NF-κB may represent a promising strategy for CRC therapy.
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Neoplasias Colorretais , DNA Glicosilases , Animais , Camundongos , Carcinogênese , Linfócitos T CD8-Positivos/metabolismo , Neoplasias Colorretais/genética , DNA Glicosilases/metabolismo , Reparo do DNA , NF-kappa B/metabolismoRESUMO
PURPOSE: To describe four Finnish families with epithelial recurrent erosion dystrophy (ERED) caused by the pathogenic variant c.3156C>T in collagen type XVII alpha 1 chain gene (COL17A1). METHODS: Eleven affected and two unaffected individuals underwent clinical ophthalmological examination, anterior segment photography, and corneal topography. Two of them underwent phototherapeutic keratectomy (PTK). Genetic analysis included both next-generation and Sanger sequencing. Specimens from the manual keratectomy of one patient were available for ophthalmic pathologic examination, including immunohistochemistry. RESULTS: The common splice-site altering synonymous variant c.3156C > T, p.(Gly1052=) in COL17A1 was confirmed in 15 individuals with ERED from the four families. Subepithelial corneal scarring grades varied and increased with age, leading to decreased best-corrected visual acuity. PTK improved vision in 58- and 67-year-old individuals without reactivating the disease. The keratectomy specimens showed an uneven epithelium and a spectrum of basement membrane abnormalities, including breaks, fragmentation, multiplication and entrapment within the subepithelial scar, reflecting recurrent erosions. The stromal cells consisted of varying proportions of bland and activated fibroblasts and myofibroblasts, reflecting different ages of scars. The family with the largest number of known affected generations originated from Southern Sweden. CONCLUSION: The phenotype in the Finnish ERED families is consistent with earlier reports of the c.3156C > T variant, although the severity has varied between reports. The phenotype may be modulated by other genes. This study suggests a likely founder effect of the variant in both Finnish and Swedish populations due to their shared population histories. If vision is compromised, PTK can be considered especially in older patients.
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Distrofias Hereditárias da Córnea , Epitélio Corneano , Ceratectomia Fotorrefrativa , Idoso , Humanos , Pessoa de Meia-Idade , Distrofias Hereditárias da Córnea/diagnóstico , Distrofias Hereditárias da Córnea/genética , Distrofias Hereditárias da Córnea/cirurgia , Epitélio Corneano/patologia , Finlândia/epidemiologia , SuéciaRESUMO
Amelogenesis imperfecta (AI) represents a group of clinically and genetically heterogeneous disorders that affect enamel formation and mineralization. Although AI is commonly considered a monogenic disorder, digenic inheritance is rarely reported. In this study, we recruited two nonconsanguineous Chinese families exhibiting diverse phenotypes of enamel defects among affected family members. Digenic variants were discovered in both probands. In family 1, the proband inherited a paternal frameshift variant in LAMA3 (NM_198129.4:c.3712dup) and a maternal deletion encompassing the entire AMELX gene. This resulted in a combined hypoplastic and hypomineralized AI phenotype, which was distinct from the parents' manifestations. In family 2, whole-exome sequencing analysis revealed the proband carried a maternal heterozygous splicing variant in COL17A1 (NC_000010.11 (NM_000494.3): c.4156 + 2dup) and compound heterozygous variants in RELT (paternal: NM_032871.4:c.260A > T; maternal: NM_032871.4:c.521 T > G). These genetic changes caused the abundant irregular enamel defects observed in the proband, whereas other affected family members carrying heterozygous variants in both COL17A1 and RELT displayed only horizontal grooves as their phenotype. The pathogenicity of the novel COL17A1 splice site variant was confirmed through RT-PCR and minigene assay. This study enhances our understanding by highlighting the potential association between the co-occurrence of variants in two genes and variable phenotypes observed in AI patients.
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Amelogênese Imperfeita , Humanos , Amelogênese Imperfeita/genética , Fenótipo , Mutação da Fase de Leitura/genética , Proteínas da Matriz Extracelular/genética , Variação Biológica da População , LinhagemRESUMO
BACKGROUND: Collagen XVII is most typically associated with human disease when biallelic COL17A1 variants (>230) cause junctional epidermolysis bullosa (JEB), a rare, genetically heterogeneous, mucocutaneous blistering disease with amelogenesis imperfecta (AI), a developmental enamel defect. Despite recognition that heterozygous carriers in JEB families can have AI, and that heterozygous COL17A1 variants also cause dominant corneal epithelial recurrent erosion dystrophy (ERED), the importance of heterozygous COL17A1 variants causing dominant non-syndromic AI is not widely recognised. METHODS: Probands from an AI cohort were screened by single molecule molecular inversion probes or targeted hybridisation capture (both a custom panel and whole exome sequencing) for COL17A1 variants. Patient phenotypes were assessed by clinical examination and analyses of affected teeth. RESULTS: Nineteen unrelated probands with isolated AI (no co-segregating features) had 17 heterozygous, potentially pathogenic COL17A1 variants, including missense, premature termination codons, frameshift and splice site variants in both the endo-domains and the ecto-domains of the protein. The AI phenotype was consistent with enamel of near normal thickness and variable focal hypoplasia with surface irregularities including pitting. CONCLUSION: These results indicate that COL17A1 variants are a frequent cause of dominantly inherited non-syndromic AI. Comparison of variants implicated in AI and JEB identifies similarities in type and distribution, with five identified in both conditions, one of which may also cause ERED. Increased availability of genetic testing means that more individuals will receive reports of heterozygous COL17A1 variants. We propose that patients with isolated AI or ERED, due to COL17A1 variants, should be considered as potential carriers for JEB and counselled accordingly, reflecting the importance of multidisciplinary care.
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Amelogênese Imperfeita , Colágenos não Fibrilares , Humanos , Colágenos não Fibrilares/genética , Colágenos não Fibrilares/metabolismo , Autoantígenos/genética , Amelogênese Imperfeita/genética , Heterozigoto , Fenótipo , Mutação/genéticaRESUMO
Junctional epidermolysis bullosa (JEB) is a rare autosomal recessive genodermatosis with a broad spectrum of phenotypes. Current genotype-phenotype paradigms are insufficient to accurately predict JEB subtype and characteristics from genotype, particularly for splice site variants, which account for over a fifth of disease-causing variants in JEB. This study evaluated the genetic and clinical findings from a JEB cohort, investigating genotype-phenotype correlations through bioinformatic analyses and comparison with previously reported variants. Eighteen unique variants in LAMB3, LAMA3, LAMC2, or COL17A1 were identified from 17 individuals. Seven had severe JEB, 9 had intermediate JEB, and 1 had laryngo-onycho-cutaneous syndrome. Seven variants were previously unreported. Deep phenotyping was completed for all intermediate JEB cases and demonstrated substantial variation between individuals. Splice site variants underwent analysis with SpliceAI, a state-of-the-art artificial intelligence tool, to predict resultant transcripts. Predicted functional effects included exon skipping and cryptic splice site activation, which provided potential explanations for disease severity and in most cases correlated with laminin-332 immunofluorescence. RT-PCR was performed for 1 case to investigate resultant transcripts produced from the splice site variant. This study expands the JEB genomic and phenotypic landscape. Artificial intelligence tools show potential for predicting the functional effects of splice site variants and may identify candidates for confirmatory laboratory investigation. Investigation of RNA transcripts will help to further elucidate genotype-phenotype correlations for novel variants.
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Colágeno Tipo XVII , Epidermólise Bolhosa Juncional , Estudos de Associação Genética , Calinina , Laminina , Colágenos não Fibrilares , Índice de Gravidade de Doença , Humanos , Epidermólise Bolhosa Juncional/genética , Epidermólise Bolhosa Juncional/patologia , Laminina/genética , Masculino , Feminino , Colágenos não Fibrilares/genética , Criança , Fenótipo , Moléculas de Adesão Celular/genética , Pré-Escolar , Autoantígenos/genética , Sítios de Splice de RNA/genética , Lactente , Adolescente , Adulto , Mutação , Adulto Jovem , GenótipoRESUMO
BACKGROUND: N6-methyladenosine (m6A) is the most abundant and reversible modification occurring in eukaryotic mRNAs, however, its functions in mammalian epidermal development are still not fully elucidated. OBJECTIVE: To explore the role of METTL14 (Methyltransferase like 14), one of the m6A methyltransferases, in maintaining epidermal homeostasis. METHODS: We constructed mice with Mettl14-inactivation in the epidermal basal cells. The phenotype was explored by H&E staining and immunofluorescence staining. To explore the underlying mechanisms, we performed RNA-seq, Ribosome profiling and MeRIP-seq on wild-type and Mettl14-inactivation epidermal keratinocytes. Moreover, HaCaT cells were used for in vitro validation. RESULTS: Inactivation of Mettl14 in murine epidermis led to transient thicker epidermis and exhaustion of the epidermal stem cell pool. Interestingly, we found that the mRNA of type XVII collagen (Col17a1), integrin ß4 (Itgß4) and α6 (Itgα6) had m6A modifications, and the proteins expression were decreased in Mettl14-inactivated epidermis. Furthermore, in epidermis-specific Mettl4-inactivated mice, the epidermis was detached from the dermis and presented a phenotype similar to junctional epidermolysis bullosa (JEB), which may result from hemidesmosomes damage (decrease of COL17A1, ITGB4 and ITGA6). Knockdown of Mettl14 in HaCaT cells impaired the self-renewal and decreased the protein level of COL17A1, ITGB4 and ITGA6 and Itgß4 knockdown inhibited colony formation. CONCLUSION: Our study highlighted the role of METTL14 in the maintenance of epidermal homeostasis and identified its critical role through m6A-mediated translational inhibition of Col17a1, Itgß4 and Itgα6. Our study suggested that METTL14 may be a potential therapeutic target for the treatment of hemidesmosomes-deficient diseases, such as JEB.
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Epidermólise Bolhosa Juncional , Integrina beta4 , Animais , Camundongos , Epiderme , Epidermólise Bolhosa Juncional/genética , Homeostase , Metiltransferases/genética , MamíferosRESUMO
Hereditary conditions that affect tooth enamel in quantity and/or quality are called amelogenesis imperfecta (AI). AI can occur as an isolated condition or as a symptom of a syndrome. An OMIM search with the term "AI" yielded 79 result entries. Mutations in the same gene cause syndromic or non-syndromic AI, depending on the nature of the mutations. In this study, we recruited two AI families and performed mutational analysis using whole-exome sequencing. The proband of family 1, with hypoplastic pitted AI and mild localized atopic dermatitis, had compound heterozygous COL17A1 mutations (paternal NM_000494.4: c.3598G>T, p.Asp1200Tyr and maternal c.1700G>A, p.Gly567Glu). The proband of family 2, with hypoplastic pitted AI and Jervell and Lange-Nielsen syndrome, had a recurrent LAMB3 mutation (NM_000228.3: c.3463_3475del, p.(Glu1155Thrfs*51)) in addition to compound heterozygous mutations in the KCNQ1 gene.
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Human skin is the most widespread and abundant type of tissue in the human body. With the passage of time, most of our organs, including a substantial part of the skin, tend to undergo a gradual thinning or decrease in size. As we age, there is a gradual and progressive reduction in the thickness of both the epidermis and dermis layers of our skin. This is primarily attributed to the decline of epidermal stem cells and the loss of dermal collagen, which is the most abundant protein in the human body. Age-related alterations of the epidermis and dermis impair skin structure/function and create a tissue microenvironment that promotes age-related skin diseases, such as impaired skin barrier, delayed wound healing, and skin cancer development. This review will examine the current body of literature pertaining to our knowledge of skin epidermal and dermal aging.
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Envelhecimento da Pele , Dermatopatias , Humanos , Pele/metabolismo , Epiderme , Dermatopatias/metabolismo , Fenômenos Fisiológicos da Pele , EnvelhecimentoRESUMO
Bazi Bushen, a Chinese-patented drug with the function of relieving fatigue and delaying ageing, has been proven effective for extenuating skin senescence. To investigate the potential mechanism, senescence-accelerated mouse prone 6 (SAMP6) was intragastrically administered with Bazi Bushen for 9 weeks to induce skin homeostasis. Skin homeostasis is important in mitigating skin senescence, and it is related to many factors such as oxidative stress, SASP, apoptosis, autophagy and stem cell. In our study, skin damage in SAMP6 mice was observed using HE, Masson and SA-ß-gal staining. The content of hydroxyproline and the activities of SOD, MDA, GSH-PX and T-AOC in the skin were measured using commercial assay kits. The level of SASP factors (IL-6, IL-1ß, TNF-α, MMP2 and MMP9) in skin were measured using ELISA kits. The protein expressions of p16, p21, p53, Bax, Bcl-2, Cleaved caspase-3, LC3, p62, Beclin1, OCT4, SOX2 and NANOG were measured by western blotting. The expression of ITGA6 and COL17A1 was measured by immunofluorescence staining and western blotting. Our findings demonstrated that Bazi Bushen alleviated skin senescence by orchestrating skin homeostasis, reducing the level of oxidative stress and the expression of SASP, regulating the balance of apoptosis and autophagy and enhancing the protein expressions of ITGA6 and COL17A1 to improve skin structure in SAMP6 mice. This study indicated that Bazi Bushen could serve as a potential therapy for alleviating skin senescence.
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Envelhecimento , Pele , Animais , Camundongos , Apoptose , Autofagia , Proteína Beclina-1RESUMO
Key Clinical Message: The presence of more than one genetic/genomic disorder is not uncommon. It is therefore essential to continuously consider new signs and symptoms over time. Administration of gene therapy could be extremely difficult in particular situations. Abstract: A 9-month-old boy presented to our department for evaluation of developmental delay. We found that he was affected by intermediate junctional epidermolysis bullosa (COL17A1, c.3766 + 1G > A, homozygous), Angelman syndrome (5,5 Mb deletion of 15q11.2-q13.1), and autosomal recessive deafness type 57 (PDZD7, c.883C > T, homozygous).
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Junctional epidermolysis bullosa (JEB) is a severe blistering skin disease caused by mutations in genes encoding structural proteins essential for skin integrity. In this study, we developed a cell line suitable for gene expression studies of the JEB-associated COL17A1 encoding type XVII collagen (C17), a transmembrane protein involved in connecting basal keratinocytes to the underlying dermis of the skin. Using the CRISPR/Cas9 system of Streptococcus pyogenes we fused the coding sequence of GFP to COL17A1 leading to the constitutive expression of GFP-C17 fusion proteins under the control of the endogenous promoter in human wild-type and JEB keratinocytes. We confirmed the accurate full-length expression and localization of GFP-C17 to the plasma membrane via fluorescence microscopy and Western blot analysis. As expected, the expression of GFP-C17mut fusion proteins in JEB keratinocytes generated no specific GFP signal. However, the CRISPR/Cas9-mediated repair of a JEB-associated frameshift mutation in GFP-COL17A1mut-expressing JEB cells led to the restoration of GFP-C17, apparent in the full-length expression of the fusion protein, its accurate localization within the plasma membrane of keratinocyte monolayers as well as within the basement membrane zone of 3D-skin equivalents. Thus, this fluorescence-based JEB cell line provides the potential to serve as a platform to screen for personalized gene editing molecules and applications in vitro and in appropriate animal models in vivo.
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Epidermólise Bolhosa Juncional , Epidermólise Bolhosa , Animais , Humanos , Epidermólise Bolhosa Juncional/genética , Edição de Genes , Pele , Mutação , Queratinócitos , Epidermólise Bolhosa/genéticaRESUMO
ADAM10 is A Disintegrin And Metalloproteinase (ADAM) family member that is membrane bound with its catalytic domain present on the cell surface. It is a sheddase that cleaves anchored cell surface proteins to shed them from the cell surface. ADAM10 can cleave at least a hundred different proteins and is expressed in most tissues of the body. ADAM10 is best characterized for its role in Notch signaling. Interestingly, ADAM10 is transported to specific sites on the cell surface by six different tetraspanins. Although the mechanism is not clear, tetraspanins can regulate ADAM10 substrate specificity, which likely contributes to the diversity of ADAM10 substrates. In developing mouse teeth, ADAM10 is expressed in the stem cell niche and subsequently in pre-ameloblasts and then secretory stage ameloblasts. However, once ameloblasts begin transitioning into the maturation stage, ADAM10 expression abruptly ceases. This is exactly when ameloblasts stop their movement that extends enamel crystallites and when the enamel layer reaches its full thickness. ADAM10 may play an important role in enamel development. ADAM10 can cleave cadherins and other cell-cell junctions at specific sites where the tetraspanins have transported it and this may promote cell movement. ADAM10 can also cleave the transmembrane proteins COL17A1 and RELT. When either COL17A1 or RELT are mutated, malformed enamel may occur in humans and mice. So, ADAM10 may also regulate these proteins that are necessary for proper enamel development. This mini review will highlight ADAM10 function, how that function is regulated by tetraspanins, and how ADAM10 may promote enamel formation.
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OBJECTIVE: This study aimed to determine the role of COL17A1 in tumor progression and predict the prognosis of pancreatic cancer (PC). METHODS: RNA-seq data from The Cancer Genome Atlas and Genotype-Tissue Expression were analyzed using bioinformatics methods. "Limma" package was used to screen differentially expressed genes (DEGs). Prognostic-associated data were further analyzed using univariate Cox regression and verified using the GSE28375 and GSE62452 datasets. Protein-protein interaction (PPI) network analysis was integrated to screen for hub genes. In vitro quantitative real-time PCR (qPCR) and western blotting were used to detect gene expression. The functional attributes of PC cells were verified by wound healing assays, migration and invasion assays, Cell Counting Kit 8 (CCK8), and 5-ethynyl-2'-deoxyuridine (EdU) assay. RESULTS: On analyzing PC data, 4637 DEGs were identified. Of these, 2399 genes were upregulated and 2238 were downregulated. Through PPI network analysis, we identified that COL17A1 expression was highly correlated with poor prognosis of patients with PC. Functional attribute assays in the in vitro study showed that COL17A1 knockdown inhibited PC cell proliferation, migration, and invasion. CONCLUSIONS: According to our results, COL17A1 promotes PC cell proliferation, migration, and invasion mediated by the epithelial-mesenchymal transition (EMT) pathway. Thus, COL17A1 could be used as a prognostic marker in PC.
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Neoplasias Pancreáticas , Humanos , Movimento Celular/genética , Linhagem Celular Tumoral , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Transição Epitelial-Mesenquimal/genética , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias PancreáticasRESUMO
Background: Epidermolysis bullosa (EB), a severe genetic disorder characterized by blister formation in skin, is caused by mutations in genes encoding dermal-epidermal junction proteins that function to hold the skin layers together. CRISPR/Cas9-induced homology-directed repair (HDR) represents a promising tool for editing causal mutations in COL17A1 in the treatment of junctional epidermolysis bullosa (JEB). Methods: In this study, we treated primary type XVII collagen (C17)-deficient JEB keratinocytes with either Cas9 nuclease or nickase (Cas9n) ribonucleoproteins (RNP) and a single-stranded oligonucleotide (ssODN) HDR template in order to correct a causal pathogenic frameshift mutation within the COL17A1 gene. Results: As analyzed by next-generation sequencing of RNP-nucleofected keratinocytes, we observed an HDR efficiency of â¼38% when cells were treated with the high-fidelity Cas9 nuclease, a mutation-specific sgRNA, and an ssODN template. The combined induction of end-joining repair and HDR-mediated pathways resulted in a C17 restoration efficiency of up to 60% as assessed by flow cytometry. Furthermore, corrected JEB keratinocytes showed a significantly increased adhesive strength to laminin-332 and an accurate deposition of C17 along the basement membrane zone (BMZ) upon differentiation into skin equivalents. Conclusion: Here we present a gene editing approach capable of reducing end joining-generated repair products while increasing the level of seamless HDR-mediated gene repair outcomes, thereby providing a promising CRISPR/Cas9-based gene editing approach for JEB.
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BACKGROUND: Uniparental disomy (UPD) is a condition in which both chromosomes are inherited from the same parent, except for imprinting disorders. Uniparental isodisomy (UPiD) may result in a homozygous variant contributing to an autosomal recessive disorder in the offspring of a heterozygous carrier. Junctional epidermolysis bullosa intermediate (JEB intermediate) is an autosomal recessive inherited disease that is associated with a series of gene variants, including those of COL17A1. CASE PRESENTATION: We report the first case of complete paternal UPiD of chromosome 10 harbouring a novel homozygous variant in COL17A1: c.1880(exon23)delG (p.G627Afs*56). This variant led to the clinical phenotype of junctional epidermolysis bullosa intermediate in a 5-year-old child. Trio-whole exome sequencing (Trio-WES) and in silico data analysis were used for variant identification, Sanger sequencing was performed for variant validation, and pathological examination was performed as the gold standard for phenotype confirmation. CONCLUSIONS: We recommend the use of WES as a first-tier test for the diagnosis of epidermolysis bullosa, especially for paediatric patients. Moreover, UPD events should be detected and analysed routinely through WES data in the future.
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Epidermólise Bolhosa Juncional , Criança , Pré-Escolar , Cromossomos Humanos Par 10 , Epidermólise Bolhosa Juncional/genética , Epidermólise Bolhosa Juncional/patologia , Heterozigoto , Homozigoto , Humanos , Dissomia UniparentalRESUMO
Collagen 17A1 (COL17A1) is a transmembrane structural component of the hemidesmosome that mediate adhesion of keratinocytes to the underlying membrane. Recent work in mouse showed that COL17A1 deficiency leads to premature skin aging. Although the role COL17A1 in skin aging is becoming recognized in mouse models, its connection to human skin natural aging/photoaging/ultraviolet (UV)-irradiated human skin has received little attention. To determine COL17A1 expression in naturally aged and photoaged as well as acutely UV irradiated human skin, skin samples were obtained from: (1) young (N = 10, 26.7±1.3 years) and aged (N = 10, 84.0 ± 1.7 years) sun-protected buttock skin; (2) photoaged extensor forearm and subject matched sun-protected underarm skin (N = 6, 56.0 ± 3.4 years); (3) solar-simulated UV-irradiated buttock skin (N = 6, 51.2 ± 3.6 years). COL17A1 levels were determined by immunohistology and RT-PCR, and the potential role of COL17A1 in epidermal aging was investigated by immunostaining of the marker for interfollicular epidermal stem cells and keratinocytes proliferation. We found that COL17A1 is specifically expressed in interfollicular epidermal stem cell niches, and that significantly reduced in naturally aged, photoaged, and acute UV-irradiated human skin in vivo. COL17A1 is identified as keratinocyte-specific collagen, and UV irradiation significantly downregulates COL17A1 expression in keratinocytes. Reduced expression of COL17A1 is positively correlated with impaired regeneration of keratinocytes and reduced dermal-epidermal junction as well as thin epidermis in aged human skin (epidermal aging). We also confirmed that keratinocyte-specific integrin ß4 (ITGB4), which interacts with COL17A1, is reduced in aged human skin. Mechanistically, we found that matrix metalloproteinases (MMPs) are responsible for UV-mediated COL17A1 degradation in both in vitro keratinocytes and in vivo mouse skin. These data suggest the possible links between reduced expression of COL17A1 and epidermal aging in human skin.
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Epidermolysis bullosa (EB) is a genetic skin disorder that shows heterogeneous clinical fragility. The patients develop skin blisters congenitally or in the early years of life at the dermo-epithelial junctions, including erosions, hyperkeratosis over the palms and soles. The other associated features are hypotrichosis on the scalp, absent or dystrophic nails, and dental anomalies. Molecular diagnosis through whole-exome sequencing (WES) has become one of the successful tool in clinical setups. In this study, three Pakhtun families from the Khyber Pakhtunkhwa province of Pakistan were ascertained. WES analysis of a proband in each family revealed two novel variants (COL17A1: NM_000494.4: c.4041T>G: p.Y1347* and PLEC: NM_201380.3: c.1283_1285delGCT: p.L426del) and one previously known COL17A1: NM_000494.4:c.3067C>T: p.Q1023*) variant in homozygous forms. Sanger sequencing of the identified variants confirmed that the heterozygous genotypes of the obligate carriers. The identified variants have not only increased the mutation spectrum of the COL17A1 and PLEC but also confirms their vital role in the morphogenesis of skin and its associated appendages. WES can be used as a first-line diagnostic tool in genetic testing and counselling families from Khyber Pakhtunkhwa, Pakistan.