Mechanistic interrogation of mutation-independent disease modulators of RDEB identifies the small leucine-rich proteoglycan PRELP as a TGF-ß antagonist and inhibitor of fibrosis.

Recessive dystrophic epidermolysis bullosa (RDEB) is a genetic extracellular matrix disease caused by deficiency in type VII collagen (Col VII). The disease manifests with devastating mucocutaneous fragility leading to progressive fibrosis and metastatic squamous cell carcinomas. Although Col VII abundance is considered the main predictor of symptom course, previous studies have revealed the existence of mutation-independent mechanisms that control disease progression. Here, to investigate and validate new molecular modifiers of wound healing and fibrosis in a natural human setting, and toward development of disease-modulating treatment of RDEB, we performed gene expression profiling of primary fibroblast from RDEB siblings with marked phenotypic variations, despite having equal COL7A1 genotype. Gene enrichment analysis suggested that severe RDEB was associated with enhanced response to TGF-ß stimulus, oxidoreductase activity, and cell contraction. Consistently, we found an increased response to TGF-ß, higher levels of basal and induced reactive oxygen species (ROS), and greater contractile ability in collagen lattices in RDEB fibroblasts (RDEBFs) from donors with severe RDEB vs mild RDEB. Treatment with antioxidants allowed a reduction of the pro-fibrotic and contractile phenotype. Importantly, our analyses revealed higher expression and deposition in skin of the relatively uncharacterized small leucine-rich extracellular proteoglycan PRELP/prolargin associated with milder RDEB manifestations. Mechanistic investigations showed that PRELP effectively attenuated fibroblasts' response to TGF-ß1 stimulus and cell contractile capacity. Moreover, PRELP overexpression in RDEBFs enhanced RDEB keratinocyte attachment to fibroblast-derived extracellular matrix in the absence of Col VII. Our results highlight the clinical relevance of pro-oxidant status and hyper-responsiveness to TGF-ß in RDEB severity and progression. Of note, our study also reveals PRELP as a novel and natural TGF-ß antagonist with a likely dermo-epidermal pro-adhesive capacity.

Epidemiology and natural history of cutaneous squamous cell carcinoma in recessive dystrophic epidermolysis bullosa patients: 20 years' experience of a reference centre in Spain.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is the leading cause of death in patients with recessive dystrophic epidermolysis bullosa (RDEB). We provide the management and prognosis of cSCC in RDEB patients at a Spanish reference center. MATERIALS AND METHODS: We retrospectively included patients with RDEB attended in La Paz University Hospital from November 1988 to October 2018. RESULTS: Fourteen patients developed at least one cSCC. Tumors were predominantly well differentiated. Nearly half of the tumors have recurred. Median time to first recurrence was 23.4 months (95% CI: 17.2-29.5). Five patients have developed distant metastases. Median overall survival (mOS) was 136.5 months since the diagnosis of the first cSCC (95% CI: 30.6-242.3). When distant metastases occurred, mOS was 6.78 months (95% CI: 1.94-11.61). CONCLUSIONS: cSCC is a life-threatening complication of RDEB patients. Although tumors are usually well differentiated, they tend to relapse. This is the first Spanish report of cSCC arising in RDEB patients.

Fibroblast activation and abnormal extracellular matrix remodelling as common hallmarks in three cancer-prone genodermatoses.

BACKGROUND: Recessive dystrophic epidermolysis bullosa (RDEB), Kindler syndrome (KS) and xeroderma pigmentosum complementation group C (XPC) are three cancer-prone genodermatoses whose causal genetic mutations cannot fully explain, on their own, the array of associated phenotypic manifestations. Recent evidence highlights the role of the stromal microenvironment in the pathology of these disorders. OBJECTIVES: To investigate, by means of comparative gene expression analysis, the role played by dermal fibroblasts in the pathogenesis of RDEB, KS and XPC. METHODS: We conducted RNA-Seq analysis, which included a thorough examination of the differentially expressed genes, a functional enrichment analysis and a description of affected signalling circuits. Transcriptomic data were validated at the protein level in cell cultures, serum samples and skin biopsies. RESULTS: Interdisease comparisons against control fibroblasts revealed a unifying signature of 186 differentially expressed genes and four signalling pathways in the three genodermatoses. Remarkably, some of the uncovered expression changes suggest a synthetic fibroblast phenotype characterized by the aberrant expression of extracellular matrix (ECM) proteins. Western blot and immunofluorescence in situ analyses validated the RNA-Seq data. In addition, enzyme-linked immunosorbent assay revealed increased circulating levels of periostin in patients with RDEB. CONCLUSIONS: Our results suggest that the different causal genetic defects converge into common changes in gene expression, possibly due to injury-sensitive events. These, in turn, trigger a cascade of reactions involving abnormal ECM deposition and underexpression of antioxidant enzymes. The elucidated expression signature provides new potential biomarkers and common therapeutic targets in RDEB, XPC and KS. What's already known about this topic? Recessive dystrophic epidermolysis bullosa (RDEB), Kindler syndrome (KS) and xeroderma pigmentosum complementation group C (XPC) are three genodermatoses with high predisposition to cancer development. Although their causal genetic mutations mainly affect epithelia, the dermal microenvironment likely contributes to the physiopathology of these disorders. What does this study add? We disclose a large overlapping transcription profile between XPC, KS and RDEB fibroblasts that points towards an activated phenotype with high matrix-synthetic capacity. This common signature seems to be independent of the primary causal deficiency, but reflects an underlying derangement of the extracellular matrix via transforming growth factor-ß signalling activation and oxidative state imbalance. What is the translational message? This study broadens the current knowledge about the pathology of these diseases and highlights new targets and biomarkers for effective therapeutic intervention. It is suggested that high levels of circulating periostin could represent a potential biomarker in RDEB.

Genetic diagnosis of epidermolysis bullosa: recommendations from an expert Spanish research group. / Diagnóstico genético de la epidermólisis bullosa: recomendaciones de un grupo español de expertos.

Epidermolysis bullosa (EB) is a rare genetic disease that causes mucocutaneous fragility. It comprises a clinically and genetically heterogeneous group of disorder characterized by spontaneous or contact/friction-induced blistering. EB is classified into 4 types-simplex, junctional, dystrophic, and Kindler syndrome-and 30 subtypes. The disease is caused by defects in proteins implicated in dermal-epidermal adhesion. At least 19 genes have been characterized and more than 1000 mutations identified, thus rendering diagnosis complex. Molecular diagnosis of EB is the last stage of a laborious process that starts with a detailed clinical history compilation and careful procurement of a skin fresh biopsy that includes an area where the epidermis detaches from the dermis. The detachment area makes it possible to establish the cleavage plane by antigen mapping and, in the best scenario, to identify a single candidate gene to search for pathogenic mutations. The results of the molecular diagnosis enable the physician to provide appropriate genetic counseling (inheritance pattern, risk of recurrence, and options for prenatal and preimplantation diagnosis) and implement subsequent preventive programs, as well as to establish a reasonable clinical prognosis facilitating access to specific therapy and rehabilitation. Lastly, molecular diagnosis is essential for the participation of patients in clinical trials, a critical issue given the current incurable status of EB. The present guidelines aim to disseminate the procedure for diagnosing EB in our laboratory and thus avoid suboptimal or incomplete clinical diagnoses. The recommendations we provide are the result of more than 10 years' experience in the molecular diagnosis of EB in Spain.

Prevalencia de la epidermólisis ampollosa distrófica en España: estudio poblacional usando el método de captura-recaptura con 3 fuentes de datos. Evidencia de la necesidad de mejora en la atención sociosanitaria / Prevalence of Dystrophic Epidermolysis Bullosa in Spain: A Population-Based Study Using the 3-Source Capture-Recapture Method. Evidence of a Need for Improvement in Care

Antecedentes: No existen datos sobre la prevalencia de la epidermólisis ampollosa distrófica en España (EAD). La EAD es una enfermedad rara que conlleva una gran carga para el paciente que la sufre y para el sistema de salud que le atiende. Objetivo: Describir la prevalencia de la EAD en España. Métodos: Hemos empleado datos procedentes de 3 fuentes incompletas de pacientes: departamentos de Dermatología, 2 laboratorios de diagnóstico y la Asociación española de pacientes con epidermólisis ampollosa, DEBRA España, y los hemos combinado usando el método de captura-recaptura. Resultados: Hemos identificado 152 pacientes vivos. La prevalencia estimada de EAD fue de 6,0 casos por millón de habitantes (IC 95%: 4,2-11,8). La prevalencia en niños menores de 18 años fue de 15,3 por millón (IC 95%: 10,4-40,8). De acuerdo con el modelo de captura-recaptura el 77% no son seguidos en unidades de referencia, el 65% no tienen diagnóstico genético y el 76% no pertenecen a DEBRA. Conclusiones: La prevalencia de EAD en España es de 6,0 pacientes por millón de habitantes (IC 95%: 4,2 a 11,8), un número mayor que el estimado en otras zonas del mundo, pero similar a otros encontrados en otros países del Sur de Europa. Este resultado puede ser debido a auténticas variaciones geográficas, o a que los otros registros recogen un número incompleto de casos. La mayoría de los pacientes no son seguidos en unidades de referencia, no tienen diagnóstico genético y no son miembros de la asociación de pacientes, lo cual quiere decir que su situación sociosanitaria es muy mejorable (AU)

Background: Dystrophic epidermolysis bullosa (DEB) is a rare disease that represents a heavy burden for both the patient and the health care system. There are currently no data on the prevalence of DEB in Spain. Objective: To determine the prevalence of DEB in Spain. Methods: We used data from 3 incomplete population-based sources (hospital dermatology departments, diagnostic laboratories performing antigenic mapping, genetic testing or both, and the Spanish Association of Epidermolysis Bullosa Patients [DEBRA]) and combined them using the 3-source capture–recapture methodology. Results: We identified 152 living DEB patients. The estimated prevalence of DEB was 6.0 cases per million (95% CI, 4.2–11.8) in adults and 15.3 (95% CI, 10.4–40.8) in children under 18 years of age. The data indicated that 77% of the patients were not being followed up in specialized centers of reference; 65% had not had a genetic diagnosis, and 76% were not members of DEBRA. Conclusions: The prevalence of DEB in Spain is 6.0 patients per million (95% CI, 4.2–11.8), a figure higher than previous estimates in many areas, but similar to those found in other southern Europe countries. The north–south difference may represent real geographic differences in prevalence, but it might be due to the fact that most of the data come from registries with a lower than expected catchment. Many patients are not being followed up in centers of reference, do not have genetic diagnosis, and are not members of patients’ associations, suggesting that there is room for considerable improvement in their care (AU)

Prevalence of dystrophic epidermolysis bullosa in Spain: a population-based study using the 3-source capture-recapture method. Evidence of a need for improvement in care.

BACKGROUND: Dystrophic epidermolysis bullosa (DEB) is a rare disease that represents a heavy burden for both the patient and the health care system. There are currently no data on the prevalence of DEB in Spain. OBJECTIVE: To determine the prevalence of DEB in Spain. METHODS: We used data from 3 incomplete population-based sources (hospital dermatology departments, diagnostic laboratories performing antigenic mapping, genetic testing or both, and the Spanish Association of Epidermolysis Bullosa Patients [DEBRA]) and combined them using the 3-source capture-recapture methodology. RESULTS: We identified 152 living DEB patients. The estimated prevalence of DEB was 6.0 cases per million (95% CI, 4.2-11.8) in adults and 15.3 (95% CI, 10.4-40.8) in children under 18 years of age. The data indicated that 77% of the patients were not being followed up in specialized centers of reference; 65% had not had a genetic diagnosis, and 76% were not members of DEBRA. CONCLUSIONS: The prevalence of DEB in Spain is 6.0 patients per million (95% CI, 4.2-11.8), a figure higher than previous estimates in many areas, but similar to those found in other southern Europe countries. The north-south difference may represent real geographic differences in prevalence, but it might be due to the fact that most of the data come from registries with a lower than expected catchment. Many patients are not being followed up in centers of reference, do not have genetic diagnosis, and are not members of patients' associations, suggesting that there is room for considerable improvement in their care.

Two novel recessive mutations in KRT14 identified in a cohort of 21 Spanish families with epidermolysis bullosa simplex.

BACKGROUND: Basal epidermolysis bullosa simplex (EBS) is a group of blistering genodermatoses mostly caused by mutations in the keratin genes, KRT5 and KRT14. Recessive mutations represent about 5% of all EBS mutations, being common and specific in populations with high consanguinity, where affected patients show severe phenotypes. OBJECTIVES: To accomplish the first mutational analysis in patients of Spanish origin with EBS and to delineate a comprehensive genotype-phenotype correlation. METHODS: Twenty-one EBS families were analysed. Immunofluorescence mapping at the dermoepidermal junction level was performed on skin biopsies from patients. Mutation screening of the entire coding sequences of KRT5 and KRT14 in genomic DNA was assessed by polymerase chain reaction and direct sequencing. RESULTS: KRT5 or KRT14 causative mutations were identified in 18 of the 21 EBS families. A total of 14 different mutations were disclosed, of which 12 were dominant missense mutations and two truncating recessive mutations. Five of the 14 mutations were novel including three dominant in KRT5 (p.V186E, p.T321P and p.A428T) and two recessive in KRT14 (p.K116X and p.K250RfsX8). The two patients with EBS carrying homozygous recessive mutations were affected by severe phenotypes and belonged to consanguineous families. All five families with the EBS Dowling-Meara subtype carried recurrent mutations affecting the highly conserved ends of the α-helical rod domain of K5 and K14. The seven mutations associated with the localized EBS subtype were widely distributed along the KRT5 and KRT14 genes. Two families with mottled pigmentation carried the P25L mutation in KRT5, commonly associated with this subtype. CONCLUSIONS: This study further confirms the genotype-phenotype correlation established for EBS in other ethnic groups, and is the first in a Mediterranean country (excluding Israel). This study adds two novel recessive mutations to the worldwide record to date, which includes a total of 14 mutations. As in previous reports, the recessive mutations resulted in a lack of keratin K14, giving rise to a generalized and severe presentation.

X-linked ichthyosis along with recessive dystrophic epidermolysis bullosa in the same patient.

X-linked ichthyosis (XLI) is a relatively common keratinization disorder which is caused, in the vast majority of cases, by a total deletion of the sulfatase steroid (STS) gene. Dystrophic epidermolysis bullosa (DEB) is a scarring form of epidermolysis bullosa of either autosomal recessive or dominant inheritance secondary to collagen VII gene mutations. We report the first case of a patient with both XLI and DEB in whom a partial deletion of the STS gene and a recessive point mutation in COL7A1 were demonstrated.

The first COL7A1 mutation survey in a large Spanish dystrophic epidermolysis bullosa cohort: c.6527insC disclosed as an unusually recurrent mutation.

BACKGROUND: Dystrophic epidermolysis bullosa (DEB) is a genodermatosis caused by mutations in COL7A1. The clinical manifestations are highly variable from nail dystrophy to life-threatening blistering, making early molecular diagnosis and prognosis of utmost importance for the affected families. Mutation identification is mandatory for prenatal testing. OBJECTIVES: To conduct the first mutational analysis of COL7A1 in a Spanish cohort, to assess mutation consequences at protein/mRNA level and to establish genotype-phenotype correlations. METHODS: Forty-nine Spanish patients with DEB were studied. Antigen mapping was performed on patient skin biopsies. COL7A1 mutation screening in genomic DNA was performed by polymerase chain reaction (PCR) and direct sequencing. Mutation consequences were determined by reverse transcriptase-PCR. RESULTS: Eight patients belonged to three unrelated families with dominant DEB. Forty-one were affected with recessive DEB (RDEB). Specifically, 27 displayed the severe generalized subtype, eight the other generalized subtype and six a localized phenotype (two pretibial, three acral and one inversa). Thirty-five mutations were identified, 20 of which are novel. The pathogenic mutation c.6527insC accounted for 46.3% of Spanish RDEB alleles. A consistent genotype-phenotype correlation was established. CONCLUSIONS: Although the COL7A1 database indicates that most DEB mutations are family specific, the pathogenic mutation c.6527insC was highly recurrent in our cohort. This level of recurrence for a single genetic defect has never previously been reported for COL7A1. Our findings are essential to the clinicians caring for patients with DEB in Spain and in the large population of Spanish descendants in Latin America. They also provide geneticists a molecular clue for a priority mutation screening strategy.

Skin gene therapy for acquired and inherited disorders.

The rapid advances associated with the Human Genome Project combined with the development of proteomics technology set the bases to face the challenge of human gene therapy. Different strategies must be evaluated based on the genetic defect to be corrected. Therefore, the re-expression of the normal counterpart should be sufficient to reverse phenotype in single-gene inherited disorders. A growing number of candidate diseases are being evaluated since the ADA deficiency was selected for the first approved human gene therapy trial (Blaese et al., 1995). To cite some of them: sickle cell anemia, hemophilia, inherited immune deficiencies, hyper-cholesterolemia and cystic fibrosis. The approach does not seem to be so straightforward when a polygenic disorder is going to be treated. Many human traits like diabetes, hypertension, inflammatory diseases and cancer, appear to be due to the combined action of several genes and environment. For instance, several wizard gene therapy strategies have recently been proposed for cancer treatment, including the stimulation of the immune system of the patient (Xue et al., 2005), the targeting of particular signalling pathways to selectively kill cancer cells (Westphal and Melchner, 2002) and the modulation of the interactions with the stroma and the vasculature (Liotta, 2001; Liotta and Kohn, 2001).

Type 3 iodothyronine deiodinase is selectively expressed in areas related to sexual differentiation in the newborn rat brain.

Thyroid hormone (T4 and T3) concentrations in target tissues are greatly influenced by the activity of iodothyronine deiodinases. Type 1 and 2 deiodinases generate T3 from T4, while deiodinase type 3 (D3) transforms T4 and T3 to inactive metabolites. Coordination of the expression and activity of these enzymes is postulated to play an important role in physiology and development, making it possible that individual cells and tissues regulate the concentrations of the active hormone according to specific needs. We have analyzed the expression of D3 in the neonatal rat brain by in situ hybridization using a specific 35S-labelled riboprobe. At postnatal day 0 D3 transcripts were unexpectedly found to be selectively expressed in areas involved in sexual differentiation of the brain such as the bed nucleus of the stria terminalis and preoptic nuclei. Expression in these areas was transient and was no longer observed at postnatal day 10. These observations suggest that D3 expression is linked to the early mechanism determining sexual function and behavior.