Elomaa O, etal., Hum Mol Genet. 2001 Apr 15;10(9):953-62.
Anhidrotic ectodermal dysplasia (EDA) is an X-linked disorder characterized by abnormal development of ectoderm and its appendices. The EDA gene encodes different isoforms of ectodysplasin, a transmembrane protein. The two longest isoforms, ectodysplasin-A1 and -A2, which differ by an insertion of t
wo amino acids, are trimeric type II membrane proteins with an extracellular portion containing a short collagenous domain and a TNF ligand motif in the C-terminal region. We show that ectodysplasin is released from cells to the culture medium. Deletion constructs were used to localize the cleavage site and show that the putative recognition sequence of a furin-like enzyme is needed for the cleavage. Some EDA patients have missense mutations affecting this recognition sequence, suggesting that cleavage has biological significance in vivo. EDAR, a recently cloned member of the TNFR family and the product of the downless gene, is able to co-precipitate ectodysplasin, confirming that they form a ligand-receptor pair. In situ hybridization and immunostaining studies show that ectodysplasin and EDAR are expressed in adjacent or partially overlapping layers in the developing human skin. We conclude that as a soluble ligand, ectodysplasin is able to interact with EDAR and mediate signals needed for the development of ectodermal appendages.
van der Hout AH, etal., Eur J Hum Genet. 2008 Jun;16(6):673-9. doi: 10.1038/sj.ejhg.5202012. Epub 2008 Jan 30.
Hypohidrotic ectodermal dysplasia (HED) can be caused by mutations in the X-linked ectodysplasin A (ED1) gene or the autosomal ectodysplasin A-receptor (EDAR) and EDAR-associated death domain (EDAR
EDARADD) genes. X-linked and autosomal forms are sometimes clinically indistinguishable. For genetic counseling in families, it is therefore important to know the gene involved. In 24 of 42 unrelated patients with features of HED, we found a mutation in ED1. ED1-negative patients were screened for mutations in EDAR and EDARADD. We found mutations in EDAR in 5 of these 18 patients. One mutation, p.Glu354X, is novel. In EDARADD, a novel variant p.Ser93Phe, probably a neutral polymorphism, was also found. Clinically, there was a difference between autosomal dominant and autosomal recessive HED patients. The phenotype in patients with mutations in both EDAR alleles was comparable to males with X-linked HED. Patients with autosomal dominant HED had features comparable to those of female carriers of X-linked HED. The teeth of these patients were quite severely affected. Hypohidrosis and sparse hair were also evident, but less severe. This study confirms Chassaing et al's earlier finding that mutations in EDAR account for approximately 25% of non-ED1-related HED. Mutations leading to a premature stop codon have a recessive effect except when the stop codon is in the last exon. Heterozygous missense mutations in the functional domains of the gene may have a dominant-negative effect with much variation in expression. Patients with homozygous or compound heterozygous mutations in the EDAR gene have a more severe phenotype than those with a heterozygous missense, nonsense or frame-shift mutation.
BACKGROUND: Hypohidrotic/anhidrotic ectodermal dysplasia (HED) is a rare Mendelian disorder affecting ectodermal tissues. The disease is primarily caused by inactivation of any one of three genes, namely ectodysplasin A1 (EDA-A1), which encodes a ligand belonging to the tumour necrosis factor (TNF)
superfamily; ectodysplasin A receptor (EDAR), encoding the EDA-A1 receptor and ectodysplasin A receptor-associated death domain (EDARADD), encoding an adaptor protein. X-linked recessive (EDA-A1), the predominant form of HED, as well as autosomal recessive and dominant (EDAR and EDARADD) inheritance patterns have been identified in affected families. OBJECTIVES: To determine the common genes causing HED in India. METHODS: We performed mutation analysis on 26 HED families from India (including 30 patients). In addition, we carried out sequence and structural analysis of missense/nonsense and insertion/deletion mutations. RESULTS: Among the 26 families analysed, disease-causing EDAR mutations were identified in 12 (46%) while EDA-A1 mutations were detected in 11 (42%). Four novel mutations in EDAR and five in EDA-A1 were identified. More importantly, a possible founder EDAR mutation, namely c.1144G>A, was identified in five independent families, thus accounting for about one-fifth of affected families in whom mutation was detected. A majority of EDA-A1 mutations localized to the TNF-like domain while the location of EDAR mutations was more widespread. CONCLUSIONS: This is the first report of a founder EDAR mutation and of a significantly high frequency of autosomal recessive HED.
Shimomura Y, etal., J Invest Dermatol. 2004 Oct;123(4):649-55. doi: 10.1111/j.0022-202X.2004.23405.x.
Hypohidrotic ectodermal dysplasia (HED) is a genetic disease characterized by abnormal hair, teeth, and sweat gland development. Although most cases of HED display X-linked recessive inheritance, autosomal dominant and autosomal recessive forms also exist. X-linked HED is caused by mutations in the
EDA gene, and the autosomal forms result from mutations in either the EDAR gene or the EDARADD gene. In this study, we identified compound heterozygous mutations in the EDAR gene in a Japanese female patient with HED. On the maternal allele is a novel splice donor site mutation of intron 2 leading to the generation of unstable transcripts with exon 2 skipping; on the paternal allele is a novel R375H transition within the death domain of EDAR. Using expression studies in tissue culture cells, we found that the R375H substitution in EDAR caused loss of its affinity for EDARADD and reduced activation of the downstream target NF-kappaB. Our findings indicate that both alleles of EDAR are non-functional in our patient, resulting in the HED phenotype.
Sisto M, etal., Clin Exp Immunol. 2016 May;184(2):183-96. doi: 10.1111/cei.12764. Epub 2016 Feb 23.
Sjogren's syndrome (SS) is an autoimmune disease and the second most common chronic systemic rheumatic disorder. Prevalence of primary SS in the general population has been estimated to be approximately 1-3%, whereas secondary SS has been observed in 10-20% of patients with rheumatoid arthritis, sy
stemic lupus erythematosus (SLE) and scleroderma. Despite this, its exact aetiology and pathogenesis are largely unexplored. Nuclear factor-kappa B (NF-kappaB) signalling mechanisms provide central controls in SS, but how these pathways intersect the pathological features of this disease is unclear. The ubiquitin-editing enzyme A20 (tumour necrosis factor-alpha-induced protein 3, TNFAIP3) serves as a critical inhibitor on NF-kappaB signalling. In humans, polymorphisms in the A20 gene or a deregulated expression of A20 are often associated with several inflammatory disorders, including SS. Because A20 controls the ectodysplasin-A1 (EDA-A1)/ectodysplasin receptor (EDAR) signalling negatively, and the deletion of A20 results in excessive EDA1-induced NF-kappaB signalling, this work investigates the expression levels of EDA-A1 and EDAR in SS human salivary glands epithelial cells (SGEC) and evaluates the hypothesis that SS SGEC-specific deregulation of A20 results in excessive EDA1-induced NF-kappaB signalling in SS. Our approach, which combines the use of siRNA-mediated gene silencing and quantitative pathway analysis, was used to elucidate the role of the A20 target gene in intracellular EDA-A1/EDAR/NF-kappaB pathway in SS SGEC, holding significant promise for compound selection in drug discovery.
Hypohidrotic and anhidrotic ectodermal dysplasia (HED/EDA) is a rare genodermatosis characterized by abnormal development of sweat glands, teeth, and hair. Three disease-causing genes have been hitherto identified, namely, (1) EDA1 accounting for X-linked forms, (2) EDAR
DAR, and (3) EDARADD, causing both autosomal dominant and recessive forms. Recently, WNT10A gene was identified as responsible for various autosomal recessive forms of ectodermal dysplasias, including onycho-odonto-dermal dysplasia (OODD) and Schopf-Schulz-Passarge syndrome. We systematically studied EDA1, EDAR, EDARADD, and WNT10A genes in a large cohort of 65 unrelated patients, of which 61 presented with HED/EDA. A total of 50 mutations (including 32 novel mutations) accounted for 60/65 cases in our series. These four genes accounted for 92% (56/61 patients) of HED/EDA cases: (1) the EDA1 gene was the most common disease-causing gene (58% of cases), (2)WNT10A and EDAR were each responsible for 16% of cases. Moreover, a novel disease locus for dominant HED/EDA mapped to chromosome 14q12-q13.1. Although no clinical differences between patients carrying EDA1, EDAR, or EDARADD mutations could be identified, patients harboring WNT10A mutations displayed distinctive clinical features (marked dental phenotype, no facial dysmorphism), helping to decide which gene should be first investigated in HED/EDA.
Bal E, etal., Hum Mutat. 2007 Jul;28(7):703-9. doi: 10.1002/humu.20500.
Anhidrotic ectodermal dysplasia (EDA) is a disorder of ectodermal differentiation characterized by sparse hair, abnormal or missing teeth, and inability to sweat. X-linked EDA is the most common form, caused by mutations in the EDA gene, which encodes ectodysplasin, a member of the tumor necrosis fa
ctor (TNF) family. Autosomal dominant and recessive forms of EDA have been also described and are accounted for by two genes. Mutations in EDAR, encoding a TNF receptor (EDAR) cause both dominant and recessive forms. In addition, mutations in a recently identified gene, EDARADD, encoding EDAR-associated death domain (EDARADD) have been shown to cause autosomal recessive EDA. Here, we report a large Moroccan family with an autosomal dominant EDA. We mapped the disease gene to chromosome 1q42.2-q43, and identified a novel missense mutation in the EDARADD gene (c.335T>G, p.Leu112Arg). Thus, the EDARADD gene accounts for both recessive and dominant EDA. EDAR is activated by its ligand, ectodysplasin, and uses EDARADD to build an intracellular complex and activate nuclear factor kappa B (NF-kB). We compared the functional consequences of the dominant (p.Leu112Arg) and recessive mutation (p.Glu142Lys), which both occurred in the death domain (DD) of EDARADD. We demonstrated that the p.Leu112Arg mutation completely abrogated NF-kB activation, whereas the p.Glu142Lys retained the ability to significantly activate the NF-kB pathway. The p.Leu112Arg mutation is probably a dominant negative form as its cotransfection impaired the wild-type EDARADD's ability to activate NF-kB. Our results confirm that NF-kB activation is impaired in EDA and support the role of EDARADD DD as a downstream effector of EDAR signaling.
Bergendal B, etal., Am J Med Genet A. 2011 Jul;155A(7):1616-22. doi: 10.1002/ajmg.a.34045. Epub 2011 May 27.
Oligodontia is defined as the congenital lack of six or more permanent teeth, excluding third molars. Oligodontia as well as hypodontia (lack of one or more permanent teeth) are highly heritable conditions associated with mutations in the AXIN2, MSX1, PAX9, EDA, and EDAR
AR genes. Here we define the prevalence of mutations in the AXIN2, MSX1, PAX9, EDA, and EDAR genes, and the novel candidate gene EDARADD in a cohort of 93 Swedish probands with non-syndromic, isolated oligodontia. Mutation screening was performed using denaturing gradient gel electrophoresis and DNA sequence analysis. Analyses of the coding sequences of the six genes showed sequence alterations predicted to be damaging or potentially damaging in ten of 93 probands (10.8%). Mutations were identified in the EDARADD (n = 1), AXIN2 (n = 3), MSX1 (n = 2), and PAX9 (n = 4) genes, respectively. None of the 10 probands with mutations had other self-reported symptoms from ectodermal tissues. The oral parameters were similar when comparing individuals with and without mutations but a family history of oligodontia was three times more frequent for probands with mutations. EDARADD mutations have previously been reported in a few families segregating hypohidrotic ectodermal dysplasia and this is, to our knowledge, the first report of an EDARADD mutation associated with isolated oligodontia.
Kuramoto T, etal., BMC Genet. 2011 Oct 21;12:91. doi: 10.1186/1471-2156-12-91.
BACKGROUND: Hypohidrotic ectodermal dysplasia (HED) is a congenital disorder characterized by sparse hair, oligodontia, and inability to sweat. It is caused by mutations in any of three Eda pathway genes: ectodysplasin (Eda), Eda receptor (Edar), and
Edar-associated death domain (Edaradd), which encode ligand, receptor, and intracellular adaptor molecule, respectively. The Eda signaling pathway activates NF-κB, which is central to ectodermal differentiation. Although the causative genes and the molecular pathway affecting HED have been identified, no curative treatment for HED has been established. Previously, we found a rat spontaneous mutation that caused defects in hair follicles and named it sparse-and-wavy (swh). Here, we have established the swh rat as the first rat model of HED and successfully identified the swh mutation. RESULTS: The swh/swh rat showed sparse hair, abnormal morphology of teeth, and absence of sweat glands. The ectoderm-derived glands, meibomian, preputial, and tongue glands, were absent. We mapped the swh mutation to the most telomeric part of rat Chr 7 and found a Pro153Ser missense mutation in the Edaradd gene. This mutation was located in the death domain of EDARADD, which is crucial for signal transduction and resulted in failure to activate NF-κB. CONCLUSIONS: These findings suggest that swh is a loss-of-function mutation in the rat Edaradd and indicate that the swh/swh rat would be an excellent animal model of HED that could be used to investigate the pathological basis of the disease and the development of new therapies.
Wohlfart S, etal., Am J Med Genet A. 2016 Jan;170A(1):249-53. doi: 10.1002/ajmg.a.37412. Epub 2015 Oct 5.
Hypohidrotic ectodermal dysplasia (HED) is a rare disorder characterized by deficient development of structures derived from the ectoderm including hair, nails, eccrine glands, and teeth. HED forms that are caused by mutations in the genes EDA, EDAR, or EDAR
yle='font-weight:700;'>EDARADD may show almost identical phenotypes, explained by a common signaling pathway. Proper interaction of the proteins encoded by these three genes is important for the activation of the NF-kappaB signaling pathway and subsequent transcription of the target genes. Mutations in the gene EDARADD are most rarely implicated in HED. Here we describe a novel missense mutation, c.367G>A (p.Asp123Asn), in this gene which did not appear to influence the interaction between EDAR and EDARADD proteins, but led to an impaired ability to activate NF-kappaB signaling. Female members of the affected family showed either unilateral or bilateral amazia. In addition, an affected girl developed bilateral ovarian teratomas, possibly associated with her genetic condition.
Li C, etal., Int J Biochem Cell Biol. 2018 Jun;99:169-177. doi: 10.1016/j.biocel.2018.03.020. Epub 2018 Apr 7.
BACKGROUND AND OBJECTIVES: Edaravone is a new type of oxygen free radical scavenger and able to attenuate various brain damage including hypoxic-ischemic brain damage (HIBD). This study was aimed at investigating the neuroprotective mechanism of edar
style='font-weight:700;'>edaravone in rat hypoxic-ischemic brain damage model and its correlation with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling pathway. MATERIALS AND METHODS: 75 seven-day-old Sprague-Dawley neonatal rats were equally divided into three groups: sham-operated group (sham), HIBD group and HIBD rats injected with edaravone (HIBD¿+¿EDA) group. Neurological severity and space cognitive ability of rats in each group were evaluated using Longa neurological severity score and Morris water maze testing. TUNEL assay and flow cytometry were used to determine brain cell apoptosis. Western blot was used to estimate the expression level of death receptor-5 (DR5), Fas-associated protein with death domain (FADD), caspase 8, B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax). In addition, immunofluorescence was performed to detect caspase 3. RESULTS: Edaravone reduced neurofunctional damage caused by HIBD and improved the cognitive capability of rats. The above experiment results suggested that edaravone could down-regulate the expression of active caspase 3 protein, thereby relieving neuronal apoptosis. CONCLUSION: Taken together, edaravone could attenuate neuronal apoptosis in rat hypoxic-ischemic brain damage model via suppression of TRAIL signaling pathway, which also suggested that edaravone might be an effective therapeutic strategy for HIBD clinical treatment.
Preclinical and clinical studies have demonstrated that a free radical scavenger edaravone has neuroprotective effects on ischemic stroke but the underlying mechanism is not fully understood. The aim of this research is to explore the effect of edar
t-weight:700;'>edaravone on the apoptotic process involving the Fas/FasL signaling pathway. Transient focal ischemia in rats was induced for 2 hours by middle cerebral artery occlusion (MCAO). After reperfusion rats were treated i.v. with either edaravone or physiological saline. The expression of Fas-associated death domain protein (FADD), death-associated protein (Daxx) and caspase-8 was examined by immunohistochemistry. The mRNA levels for FADD and Daxx by reverse-transcriptase PCR (RT-PCR) and apoptosis was assessed by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL). Neurological scores and infarction volumes were also evaluated. Edaravone significantly improved the neurological outcome (p<0.05) and reduced the total infarct volumes (p<0.05), compared with saline control. In addition, edaravone-treatment significantly reduced the number of TUNEL-positive cells (p<0.01), reduced expression levels of FADD, Daxx and caspase-8 immunoreactivity (p <0.05 approximately 0.01), and decreased mRNA levels of FADD and Daxx (p<0.05 approximately 0.01) within the peri-infarct area. We conclude that edaravone may protect ischemic neurons from apoptosis via suppressing the gene expression of the Fas/FasL signaling pathway.
Fan J, etal., Int J Neurosci. 2012 Nov;122(11):665-74. doi: 10.3109/00207454.2012.707714. Epub 2012 Aug 21.
Edaravone, a free radical scavenger, has shown neuroprotection properties in both animals and humans. To evaluate the mechanisms involved, we obtained a culture of almost pure neurons. The neurons, either untreated or prophylactically treated with edar
ont-weight:700;'>edaravone, were exposed to 300 muM hydrogen peroxide. We examined alterations in mitochondria, the percent of apoptotic cells and the immunoblots of key regulatory proteins, and the protein-protein interactions and the cellular locations of cytochrome c. The levels of p-JNK (Thr183/Tyr185) and cytochrome c in cytosol and BAX in heavy membrane (HM), respectively, were increased at 0.5 h and reached the peak at 12 h after stimulation with hydrogen peroxide. The levels of p-BAD and BAX in the cytosol and the interaction between BAD and 14-3-3 were decreased in the untreated neurons. However, edaravone could prevent these changes. In addition, mitochondrial morphology was better preserved and the percentage of apoptosis was lower under the treatment with edaravone. In summary, the present study indicates that edaravone could protect neurons by inhibiting: (1) the activity of JNK, (2) the disassociation of BAD from 14-3-3, and (3) the translocation of BAX from cytosol to mitochondria.
Peng Q, etal., Hum Genet. 2016 Jan;135(1):99-108. doi: 10.1007/s00439-015-1618-6. Epub 2015 Nov 24.
An adaptive variant of human Ectodysplasin receptor, EDARV370A, had undergone strong positive selection in East Asia. In mice and humans, EDARV370A was found to affect ectodermal-derived characteristics, including hair thick
ness, hair shape, active sweat gland density and teeth formation. Facial characteristics are also largely ectodermal derived. In this study, taking advantage of an admixed population of East Asian and European ancestry-the Uyghur, we aim to test whether EDARV370A is affecting facial characteristics and to investigate its pleiotropic nature and genetic model. In a sample of 1027 Uyghurs, we discover that EDARV370A is significantly associated with several facial characteristics, in particular shape of earlobe (P = 3.64 x 10 (-6) ) and type of chin (P = 9.23 x 10 (-5) ), with successful replication in other East Asian populations. Additionally, in this Uyghur population, we replicate previous association findings of incisors shoveling (P = 1.02 x 10 (-7) ), double incisors shoveling (P = 1.86 x 10 (-12) ) and hair straightness (P = 3.99 x 10 (-16) ), providing strong evidence supporting an additive model for the EDARV370A associations. Partial least square path model confirms EDARV370A systematically affect these weakly related ectodermal-derived characteristics, suggesting the pleiotropic effect of EDARV370A mainly plays roles in early embryo development. This study extends our knowledge about the pleiotropic nature of EDARV370A and provides potential clues to its adaptation fitness in human evolution.
The study aimed to investigate the influences of edaravone on necroptosis-related proteins and oxidative stress in rats with lower extremity ischemia/reperfusion (I/R) injury. The normal group (n=10), model group (lower extremity I/R injury model, n=10), treatme
nt group (treatment with edaravone, n=10) and intervention group [lower extremity I/R injury model intervened with necrostatin-1 (Nec-1), n=10] were set. A conventional biochemical test was adopted to detect hepatic function indexes, and an enzyme-linked immunosorbent assay was performed to measure the levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), superoxide dismutase (SOD) and myeloperoxidase (MPO). The apoptosis level in rat tissues was determined via terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) assay. The expression levels of genes and proteins were measured via quantitative polymerase chain reaction (qPCR) and Western blotting assay. The content of serum alkaline phosphatase (ALP), glutamic-pyruvic transaminase (GPT) and creatine kinase isoenzyme (CK-MB) was remarkably higher in the model group than that in the normal group. The levels of TNF-α, IL-6 and IL-1 were increased markedly in the model group, and the content of MDA in anterior tibial muscle tissues was also raised. The SOD content was elevated in the treatment group and intervention group. The number of apoptotic cells was larger than that in other groups (p<0.05). The gene expression levels of receptor-interacting protein kinase 1 (RIPK1), RIPK3, mixed lineage kinase domain-like (MLKL) and Caspase-3 were prominently higher in the model group than those in the treatment group and intervention group (p<0.05). The expression level of SOD in the treatment group and intervention group increased remarkably compared with that in the model group (p<0.05). RIPK1 and MLKL were raised evidently in the model group (p<0.05). Edaravone may regulate necroptosis-related proteins and oxidative stress in rats with lower extremity I/R injury by inhibiting the RIPK1-MLKL signaling pathway.
