RESUMO
Desmoplakin (DSP) is a desmosomal component expressed in skin and heart, essential for desmosome stability and intermediate filament connection. Pathogenic variants in the DSP gene encoding DSP, lead to heterogeneous skin, adnexa and heart-related phenotypes, including skin fragility, woolly hair (WH), palmoplantar keratoderma (PPK) and arrhythmogenic/dilated cardiomyopathy (ACM/DCM). The ambiguity of computer-based prediction analysis of pathogenicity and effect of DSP variants, indicates a necessity for functional analysis. Here, we report a heterozygous DSP variant that was not previously described, NM_004415.4:c.3337C>T (NM_004415.4(NP_004406.2):p.(Arg1113*)) in a patient with PPK, WH and ACM. RNA and protein analysis revealed ~50% reduction of DSP mRNA and protein expression. Patient's keratinocytes showed fragile cell-cell connections and perinuclear retracted intermediate filaments. Epidermal growth factor receptor (EGFR) is a transmembrane protein expressed in the basal epidermal layer involved in proliferation and differentiation, processes that are disrupted in the development of PPK, and in the regulation of the desmosome. In skin of the abovementioned patient, evident EGFR upregulation was observed. EGFR inhibition in patient's keratinocytes strongly increased DSP expression at the plasma membrane, improved intermediate filament connection with the membrane edges and reduced the cell-cell fragility. This cell phenotypic recovery was due to a translocation of DSP to the plasma membrane together with an increased number of desmosomes. These results indicate a therapeutic potential of EGFR inhibitors for disorders caused by DSP haploinsufficiency.
Assuntos
Desmoplaquinas , Receptores ErbB , Doenças do Cabelo , Ceratodermia Palmar e Plantar , Humanos , Desmoplaquinas/genética , Desmoplaquinas/metabolismo , Epiderme/metabolismo , Receptores ErbB/genética , Receptores ErbB/metabolismo , Doenças do Cabelo/genética , Queratinócitos/metabolismo , Ceratodermia Palmar e Plantar/genética , Fenótipo , Pele/metabolismoRESUMO
Pemphigus vulgaris (PV) is a rare autoimmune bullous disease characterized by blistering of the skin and mucosa owing to the presence of autoantibodies against the desmosome proteins desmoglein 3 and occasionally in conjunction with desmoglein 1. Fundamental research into the pathogenesis of PV has revolutionized its treatment and outcome with rituximab, a B-cell-depleting therapy. The critical contribution of B cells to the pathogenesis of pemphigus is well accepted. However, the exact pathomechanism, mechanisms of onset, disease course and relapse remain unclear. In this narrative review, we provide an overview of the fundamental research progress that has unfolded over the past few centuries to give rise to current and emerging therapies. Furthermore, we summarize the multifaceted roles of B cells in PV, including their development, maturation and antibody activity. Finally, we explored how these various aspects of B-cell function contribute to disease pathogenesis and pave the way for innovative therapeutic interventions.
Pemphigus vulgaris (PV) is a rare autoimmune disease, in which the immune system attacks itself and causes blisters on the skin and inside the mouth. This happens because the body mistakenly attacks specific proteins (called desmosomes) that keep the skin together. Globally, this disease affects anywhere from 0.5 to 16.1 people per million, often older than 50â years. PV is life-threatening when left untreated. From carrying out research as far back as the 1700s, we have made significant strides in understanding PV. For example, research has led to a new treatment with the antibody rituximab, which works by eliminating the cells of the immune system that attack desmosomes (called B cells). However, after therapy is completed, the disease often returns because the same troublesome B cells reappear. There are multiple places that are involved when the body attacks desmosomes. The problems range from the bone marrow where the B cells are made and selected to the ways these cells change as they move around the body. It takes a rare combination of these changes to switch from a normal immune system to one that causes PV. Clinicians and researchers are currently developing new treatment options to better target this skin disease. We want to emphasize that research should continue to uncover how the disease works because a better understanding promotes the development of new therapies, and perhaps even a cure. This is vital, because PV can significantly lower the quality of life of people living with this skin disease.
Assuntos
Linfócitos B , Pênfigo , Rituximab , Pênfigo/imunologia , Pênfigo/tratamento farmacológico , Pênfigo/terapia , Humanos , Linfócitos B/imunologia , Rituximab/uso terapêutico , Autoanticorpos/imunologia , Tolerância Imunológica/imunologiaRESUMO
BACKGROUND: Paraneoplastic pemphigus (PNP) is an extremely rare life-threatening blistering autoimmune disease that is associated with an underlying neoplasm. There is a set diagnostic criterion for PNP, which is primarily based on a severe stomatitis and the detection of specific antibodies against envoplakin, periplakin and alpha-2-macroglobulin-like protein 1. However, it has become increasingly evident that there are patients with PNP that do not meet all the diagnostic criteria requirements. OBJECTIVES: The aim of this study was to analyse our cohort of Dutch patients and to define the atypical cases that did not meet the diagnostic criteria. METHODS: A retrospective case study of all known Dutch PNP patients of the past 25 years. Patients' clinical and immunological variables were thoroughly analysed and described. RESULTS: Twenty-four patients were included in this study. The results revealed several atypical patient cases that did not completely meet the set diagnostic criteria. Of the 24 patients, two patients presented without stomatitis, in three patients an underlying neoplasm could not be detected, and in two patients the presence of specific autoantibodies could not be demonstrated, although all other criteria for PNP were met. Finally, three of the 24 patients survived the disease. CONCLUSION: Although our findings showed similarities to previous studies and most of the patients met the criteria, there were a few atypical patient cases; highlighting the importance of not strictly adhering to the set criteria when making a diagnosis, as this can lead to a missed or late diagnosis. Thus, it is of crucial importance to combine clinical and elaborate laboratory results to confirm the diagnosis of PNP in suspected patients. Although PNP harbours an unfavourable prognosis in most cases, it might be resolved by timely treatment of the underlying cause.
Assuntos
Síndromes Paraneoplásicas , Pênfigo , Estomatite , Humanos , Estudos Retrospectivos , Países Baixos , Síndromes Paraneoplásicas/diagnóstico , Síndromes Paraneoplásicas/etiologia , Estomatite/complicaçõesRESUMO
Epidermolysis bullosa is a group of genetic skin conditions characterized by abnormal skin (and mucosal) fragility caused by pathogenic variants in various genes. The disease severity ranges from early childhood mortality in the most severe types to occasional acral blistering in the mildest types. The subtype and severity of EB is linked to the gene involved and the specific variants in that gene, which also determine its mode of inheritance. Current treatment is mainly focused on symptomatic relief such as wound care and blister prevention, because truly curative treatment options are still at the preclinical stage. Given the current level of understanding, the broad spectrum of genes and variants underlying EB makes it impossible to develop a single treatment strategy for all patients. It is likely that many different variant-specific treatment strategies will be needed to ultimately treat all patients. Antisense-oligonucleotide (ASO)-mediated exon skipping aims to counteract pathogenic sequence variants by restoring the open reading frame through the removal of the mutant exon from the pre-messenger RNA. This should lead to the restored production of the protein absent in the affected skin and, consequently, improvement of the phenotype. Several preclinical studies have demonstrated that exon skipping can restore protein production in vitro, in skin equivalents, and in skin grafts derived from EB-patient skin cells, indicating that ASO-mediated exon skipping could be a viable strategy as a topical or systemic treatment. The potential value of exon skipping for EB is supported by a study showing reduced phenotypic severity in patients who carry variants that result in natural exon skipping. In this article, we review the substantial progress made on exon skipping for EB in the past 15 years and highlight the opportunities and current challenges of this RNA-based therapy approach. In addition, we present a prioritization strategy for the development of exon skipping based on genomic information of all EB-involved genes.
Assuntos
Epidermólise Bolhosa , Éxons , Fibroblastos/imunologia , Mutação , Oligonucleotídeos Antissenso , Pele/imunologia , Epidermólise Bolhosa/genética , Epidermólise Bolhosa/imunologia , Epidermólise Bolhosa/terapia , Humanos , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/uso terapêuticoRESUMO
Human skin graft mouse models are widely used to investigate and develop therapeutic strategies for the severe generalized form of recessive dystrophic epidermolysis bullosa (RDEB), which is caused by biallelic null mutations in COL7A1 and the complete absence of type VII collagen (C7). Most therapeutic approaches are focused on reintroducing C7. Therefore, C7 and anchoring fibrils are widely used as readouts in therapeutic research with skin graft models. In this study, we investigated the expression pattern of human and murine C7 in a grafting model, in which human skin is reconstituted out of in vitro cultured keratinocytes and fibroblasts. The model revealed that murine C7 was deposited in both human healthy control and RDEB skin grafts. Moreover, we found that murine C7 is able to form anchoring fibrils in human grafts. Therefore, we advocate the use of human-specific antibodies when assessing the reintroduction of C7 using RDEB skin graft mouse models.
Assuntos
Colágeno Tipo VII/biossíntese , Colágeno Tipo VII/metabolismo , Epidermólise Bolhosa Distrófica/patologia , Fibroblastos/metabolismo , Queratinócitos/metabolismo , Transplante de Pele , Animais , Anticorpos Heterófilos/imunologia , Membrana Basal/metabolismo , Células Cultivadas , Colágeno Tipo VII/deficiência , Colágeno Tipo VII/genética , Colágeno Tipo VII/imunologia , Derme/patologia , Epidermólise Bolhosa Distrófica/imunologia , Feminino , Fibroblastos/transplante , Expressão Gênica , Xenoenxertos , Humanos , Queratinócitos/transplante , Masculino , Camundongos , Camundongos SCID , Modelos Animais , Técnica de Janela CutâneaRESUMO
Genetic disorders affecting the skin, genodermatoses, constitute a large and heterogeneous group of diseases, for which treatment is generally limited to management of symptoms. RNA-based therapies are emerging as a powerful tool to treat genodermatoses. In this review, we discuss in detail RNA splicing modulation by antisense oligonucleotides and RNA trans-splicing, transcript replacement and genome editing by in vitro-transcribed mRNAs, and gene knockdown by small interfering RNA and antisense oligonucleotides. We present the current state of these therapeutic approaches and critically discuss their opportunities, limitations and the challenges that remain to be solved. The aim of this review was to set the stage for the development of new and better therapies to improve the lives of patients and families affected by a genodermatosis.
Assuntos
Terapia Genética/métodos , RNA/uso terapêutico , Dermatopatias Genéticas/terapia , Animais , Técnicas de Silenciamento de Genes , Humanos , Oligonucleotídeos Antissenso/uso terapêutico , RNA Mensageiro/uso terapêutico , Trans-SplicingRESUMO
Genetically evoked deficiency of collagen VII causes dystrophic epidermolysis bullosa (DEB)-a debilitating disease characterized by chronic skin fragility and progressive fibrosis. Removal of exons carrying frame-disrupting mutations can reinstate protein expression in genetic diseases. The therapeutic potential of this approach is critically dependent on gene, protein, and disease intrinsic factors. Naturally occurring exon skipping in COL7A1, translating collagen VII, suggests that skipping of exons containing disease-causing mutations may be feasible for the treatment of DEB. However, despite a primarily in-frame arrangement of exons in the COL7A1 gene, no general conclusion of the aptitude of exon skipping for DEB can be drawn, since regulation of collagen VII functionality is complex involving folding, intra- and intermolecular interactions. To directly address this, we deleted two conceptually important exons located at both ends of COL7A1, exon 13, containing recurrent mutations, and exon 105, predicted to impact folding. The resulting recombinantly expressed proteins showed conserved functionality in biochemical and in vitro assays. Injected into DEB mice, the proteins promoted skin stability. By demonstrating functionality of internally deleted collagen VII variants, our study provides support of targeted exon deletion or skipping as a potential therapy to treat a large number of individuals with DEB.
Assuntos
Colágeno Tipo VII/genética , Epidermólise Bolhosa Distrófica/genética , Éxons , Marcação de Genes , Deleção de Sequência , Processamento Alternativo , Animais , Adesão Celular/genética , Linhagem Celular , Movimento Celular/genética , Colágeno Tipo VII/química , Epidermólise Bolhosa Distrófica/metabolismo , Epidermólise Bolhosa Distrófica/patologia , Epidermólise Bolhosa Distrófica/terapia , Humanos , Camundongos , Oligonucleotídeos Antissenso/genética , Dobramento de Proteína , Estabilidade Proteica , Fases de Leitura , Pele/metabolismo , Relação Estrutura-AtividadeRESUMO
Background: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare and potentially life-threatening mucocutaneous blistering diseases that clinically can resemble autoimmune bullous diseases. Moreover, it has been shown that autoantibodies against epidermal proteins are present in SJS/TEN. Objectives: To establish the presence of antibodies against desmosomal and hemidesmosomal proteins in confirmed SJS/TEN patients. Methods: Serum of SJS/TEN patients diagnosed based on clinical criteria, e.g., epidermal detachment with erosions and severe mucosal lesions, (suspicion of) a culprit drug, and matching histologic results was evaluated by various techniques, e.g., indirect immunofluorescence on monkey esophagus, salt split skin and rat bladder, immunoblotting (IB) and immunoprecipitation (IP), ELISAs against desmogleins and BP180, keratinocyte footprint assay, and keratinocyte binding assay. Results: A total of 28 patients were included in this study, 15 men and 13 women with a mean age of 56 years. In most patients, none of the serological tests were positive. In two patients, an elevated DSG3 titer was found suspicious for pemphigus vulgaris. Three patients had elevated NC16a titers, suggesting bullous pemphigoid. However, in all these patients, no other tests were positive and in these patients, the biopsy for direct immunofluorescence showed no evidence for an autoimmune bullous disease. Three patients showed reactivity against rat bladder rat bladder; these were, however, completely negative for A2ML1, envoplakin, and periplakin in the IB as well as the IP. Conclusions: Serological analysis for desmosomal and hemidesmosomal antibodies is reliable to rule an autoimmune bullous disease in patients with suspected SJS/TEN. However, one should not rely on one single test method since false positive results can occur. Moreover, this study also makes it less plausible that antibodies against desmosomal and/or hemidesmosomal components are involved in the pathogenesis of SJS/TEN.
RESUMO
Desmosomes are dynamic complex protein structures involved in cellular adhesion. Disruption of these structures by loss-of-function variants in desmosomal genes leads to a variety of skin- and heart-related phenotypes. In this study, we report TUFT1 as a desmosome-associated protein, implicated in epidermal integrity. In two siblings with mild skin fragility, woolly hair, and mild palmoplantar keratoderma but without a cardiac phenotype, we identified a homozygous splice-site variant in the TUFT1 gene, leading to aberrant mRNA splicing and loss of TUFT1 protein. Patients' skin and keratinocytes showed acantholysis, perinuclear retraction of intermediate filaments, and reduced mechanical stress resistance. Immunolabeling and transfection studies showed that TUFT1 is positioned within the desmosome and that its location is dependent on the presence of the desmoplakin carboxy-terminal tail. A Tuft1-knockout mouse model mimicked the patients' phenotypes. Altogether, this study reveals TUFT1 as a desmosome-associated protein, whose absence causes skin fragility, woolly hair, and palmoplantar keratoderma.
Assuntos
Doenças do Cabelo , Ceratodermia Palmar e Plantar , Anormalidades da Pele , Animais , Humanos , Camundongos , Desmoplaquinas/genética , Desmoplaquinas/metabolismo , Desmossomos/metabolismo , Cabelo/metabolismo , Doenças do Cabelo/genética , Doenças do Cabelo/metabolismo , Ceratodermia Palmar e Plantar/genética , Ceratodermia Palmar e Plantar/metabolismo , Pele/metabolismo , Anormalidades da Pele/metabolismoRESUMO
The genodermatosis dystrophic epidermolysis bullosa (DEB) is caused by mutations in the COL7A1 gene which encodes type VII collagen (C7). In the cutaneous basement membrane zone, C7 secures attachment of the epidermal basal keratinocyte to the papillary dermis by means of anchoring fibril formation. The complete absence of these anchoring fibrils leads to severe blistering of skin and mucosa upon the slightest friction and early mortality. To date, although preclinical advances toward therapy are promising, treatment for the disease is merely symptomatic. Therefore, research into novel therapeutics is warranted.Antisense oligonucleotide (ASO)-mediated exon skipping is such a therapy . Clinical examination of naturally occurring exon skipping suggested that this mechanism could most likely benefit the most severely affected patients. The severe form of DEB is caused by biallelic null mutations. Exon skipping aims to bind an ASO to the mutated exon of the pre-mRNA in the cell nucleus. Thereby, the ASO inhibits the recognition of the mutated exon by the splicing machinery, and as a result, the mutated exon is spliced out from the mRNA with its surrounding introns, i.e., it is skipped. Here, we describe in vitro methods to evaluate ASO-mediated exon skipping in a preclinical setting.
Assuntos
Epidermólise Bolhosa Distrófica , Oligonucleotídeos Antissenso , Colágeno Tipo VII/genética , Epidermólise Bolhosa Distrófica/genética , Epidermólise Bolhosa Distrófica/terapia , Éxons/genética , Humanos , Mutação , Oligonucleotídeos Antissenso/genética , Pele/metabolismoRESUMO
Here, we describe an in vivo model in which antisense oligonucleotides were preclinically evaluated in reconstituted patient and healthy control skin. The aim was to investigate the effect of antisense oligonucleotides upon local or systemic administration. This allows for clinically relevant evaluation of antisense oligonucleotides in an in vivo setting. In this model, primary human keratinocytes and fibroblasts were placed into silicone grafting chambers, implanted onto the back of athymic nude mice. After sufficient cells were expanded, within a few weeks, human skin grafts were generated with a high success rate. These mice bearing grafts were subsequently treated with antisense oligonucleotides targeting exon 105 of the COL7A1 gene which encodes type VII collagen. Patients completely lacking expression of type VII collagen develop severe blistering of skin and mucosa, i.e., recessive dystrophic epidermolysis bullosa. In this chapter, we describe the in vivo model used for the preclinical evaluation of antisense oligonucleotides as therapeutic approach for recessive dystrophic epidermolysis bullosa.
Assuntos
Epidermólise Bolhosa Distrófica , Oligonucleotídeos Antissenso , Animais , Colágeno Tipo VII/genética , Colágeno Tipo VII/metabolismo , Epidermólise Bolhosa Distrófica/genética , Epidermólise Bolhosa Distrófica/terapia , Humanos , Camundongos , Camundongos Nus , Oligonucleotídeos Antissenso/genética , Pele/metabolismoRESUMO
Dystrophic epidermolysis bullosa (DEB) is a devastating blistering disease affecting skin and mucous membranes. It is caused by pathogenic variants in the COL7A1 gene encoding type VII collagen, and can be inherited dominantly or recessively. Recently, promising proof-of-principle has been shown for antisense oligonucleotide (AON)-mediated exon skipping as a therapeutic approach for DEB. However, the precise phenotypic effect to be anticipated from exon skipping, and which patient groups could benefit, is not yet clear. To answer these questions, we studied new clinical and molecular data on seven patients from the Dutch EB registry and reviewed the literature on COL7A1 exon skipping variants. We found that phenotypes associated with dominant exon skipping cannot be distinguished from phenotypes caused by other dominant DEB variants. Recessive exon skipping phenotypes are generally relatively mild in the spectrum of recessive DEB. Therefore, for dominant DEB, AON-mediated exon skipping is unlikely to ameliorate the phenotype. In contrast, the overall severity of phenotypes associated with recessive natural exon skipping pivots toward the milder end of the spectrum. Consequently, we anticipate AON-mediated exon skipping for recessive DEB caused by bi-allelic null variants should lead to a clinically relevant improvement of this devastating phenotype.
RESUMO
The "generalized severe" form of recessive dystrophic epidermolysis bullosa (RDEB-gen sev) is caused by bi-allelic null mutations in COL7A1, encoding type VII collagen. The absence of type VII collagen leads to blistering of the skin and mucous membranes upon the slightest trauma. Because most patients carry exonic point mutations or small insertions/deletions, most exons of COL7A1 are in-frame, and low levels of type VII collagen already drastically improve the disease phenotype, this gene seems a perfect candidate for antisense oligonucleotide (AON)-mediated exon skipping. In this study, we examined the feasibility of AON-mediated exon skipping in vitro in primary cultured keratinocytes and fibroblasts, and systemically in vivo using a human skin-graft mouse model. We show that treatment with AONs designed against exon 105 leads to in-frame exon 105 skipping at the RNA level and restores type VII collagen protein production in vitro. Moreover, we demonstrate that systemic delivery in vivo induces de novo expression of type VII collagen in skin grafts generated from patient cells. Our data demonstrate strong proof-of-concept for AON-mediated exon skipping as a systemic therapeutic strategy for RDEB.