Ectodysplasin A/Ectodysplasin A Receptor System and Their Roles in Multiple Diseases

EDA2R reflects the acute brain response to cranial irradiation in liquid biopsies

BACKGROUND

Cranial radiotherapy is standard of care for high-grade brain tumors and metastases; however, it induces debilitating neurocognitive impairments in cancer survivors, especially children. As the numbers of pediatric brain cancer survivors continue improving, the numbers of individuals developing life-long neurocognitive sequalae are consequently expected to rise. Yet, there are no established biomarkers estimating the degree of the irradiation-induced brain injury at completion of radiotherapy to predict the severity of the expected neurocognitive complications. We aimed to identify sensitive biomarkers associated with brain response to irradiation that can be measured in easily accessible clinical materials, such as liquid biopsies.

METHODS

Juvenile mice were subjected to cranial irradiation with 0.5, 1, 2, 4, and 8 Gy. Cerebrospinal fluid (CSF), plasma, and brains were collected at acute, subacute, and subchronic phases after irradiation, and processed for proteomic screens, and molecular and histological analyses.

RESULTS

We found that the levels of ectodysplasin A2 receptor (EDA2R), member of tumor necrosis factor receptor superfamily, increased significantly in the CSF after cranial irradiation, even at lower irradiation doses. The levels of EDA2R were increased globally in the brain acutely after irradiation and decreased over time. EDA2R was predominantly expressed by neurons, and the temporal dynamics of EDA2R in the brain was reflected in the plasma samples.

CONCLUSIONS

We propose EDA2R as a promising potential biomarker reflecting irradiation-induced brain injury in liquid biopsies. The levels of EDA2R upon completion of radiotherapy may aid in predicting the severity of IR-induced neurocognitive sequalae at a very early stage after treatment.

EDA2R-NIK signaling in cancer cachexia

PURPOSE OF REVIEW

Cachexia is a debilitating condition causing weight loss and skeletal muscle wasting that negatively influences treatment and survival of cancer patients. The objective of this review is to describe recent discoveries on the role of a novel signaling pathway involving ectodysplasin A2 receptor (EDA2R) and nuclear factor κB (NFκB)-inducing kinase (NIK) in muscle atrophy.

RECENT FINDINGS

Studies identified tumor-induced upregulation of EDA2R expression in muscle tissues in pre-clinical cachexia models and patients with various cancers. Activation of EDA2R by its ligand promoted atrophy in cultured myotubes and muscle tissue, which depended on NIK activity. The non-canonical NFκB pathway via NIK also stimulated muscle atrophy. Mice lacking EDA2R or NIK were protected from muscle loss due to tumors. Tumor-induced cytokine oncostatin M (OSM) upregulated EDA2R expression in muscles whereas OSM receptor-deficient mice were resistant to muscle wasting.

SUMMARY

Recent discoveries revealed a mechanism involving EDA2R-NIK signaling and OSM that drives cancer-associated muscle loss, opening up new directions for designing anti-cachexia treatments. The therapeutic potential of targeting this mechanism to prevent muscle loss should be further investigated. Future research should also explore broader implications of the EDA2R-NIK pathway in other muscle wasting diseases and overall muscle health.

Plasma Protein Profiling to Discern Indolent from Advanced Systemic Mastocytosis

Mastocytosis is a heterogeneous disorder characterized by abnormal mast cell accumulation, in which the clinical severity may be explained by distinct molecular mechanisms. This study aimed to explore plasma protein biomarkers associated with systemic mastocytosis subtypes, as well as the cellular origin of the identified proteins. Plasma samples from patients with mastocytosis, including cutaneous mastocytosis (CM), indolent systemic mastocytosis (ISM), and advanced systemic mastocytosis (AdvSM), and a reference group of patients with polycythemia vera, were analyzed by Proximity Extension Assay technology targeting 275 proteins. Furthermore, potential cellular origin was explored using an available single-cell RNA-sequencing data set generated from patients with ISM. The study cohort included 16 patients with CM, 92 patients with systemic mastocytosis (ISM, n = 80; AdvSM, n = 12), and 60 patients with polycythemia vera. A principal component analysis based on 275 plasma proteins revealed one cluster of patients with CM and ISM that was separated from patients with AdvSM. Up to 29 proteins were associated with distinct severe activity in patients with systemic mastocytosis (ISM versus AdvSM), including IL-1 receptor type 1 (IL-1RT1) and tumor necrosis factor ligand superfamily member 13B (TNFSF13B) (q < 0.01). Furthermore, single-cell RNA-sequencing analysis from ISM-derived bone marrow cells revealed that the mRNA for the identified proteins was not exclusive of mast cells. Distinct plasma protein profiles show potential to refine ISM and AdvSM diagnoses, possibly reflecting differences in pathogenic mechanisms and diverse clinical manifestations.

Application of digital virtual simulated design in the prosthodontic rehabilitation of a child with a novel EDA mutation in ectodermal dysplasia: A clinical report

This clinical report presents a 7-year-old patient with ectodermal dysplasia and a newly identified ectodysplasin A (EDA) gene mutation (c.965 T>C). A removable partial denture combined with a complete denture was provided after considering the relevant factors. Based on digital smile design, resin crowns were fabricated to restore the cone-shaped teeth esthetically. Facial scan parameters and maxillofacial landmark localization on cone beam computed tomography (CBCT) images were combined for the registration of jaw relation, and a Gothic arch was subsequently 3-dimensionally printed for verification. Ultimately, dentures with accurate occlusion and satisfactory retention were delivered for this young patient with inadequate bone volume and poor fit that markedly improved his esthetics and function.

Identification of cancer-associated fibroblast-related Ectodysplasin-A as a novel indicator for prognosis and immune response in gastric cancer

Studies have indicated cancer-associated fibroblasts (CAFs) could have a significant impact in gastric cancer (GC) progression and chemotherapy resistance. However, the gene related to cancer fibroblasts that can be used as biomarkers to judge the occurrence of gastric cancer has not been fully explored. Based on two Gene Expression Omnibus (GEO) datasets, we focus on differentially expressed genes which may act as CAFs markers related to GC. Through COX regression, LASSO regression and Kaplan-Meier survival analysis, we discovered three upregulated genes (GLT8D2, GNAS and EDA) associated with poor GC patients' survival. By single-cell analysis and nomogram, we found that EDA may affect fibroblast production and disease prognosis in GC patients. EDA expression showed a positive correlation with 5-Fluorouracil IC50 values. Immunohistochemistry (IHC) and real time PCR indicated elevated EDA levels in GC tissues and cells. Enrichment analysis revealed that EDA was closely linked to immune system regulation. IHC and single-cell analysis indicated that EDA gene was associated with cancer fibroblasts marker FGF12 and influence cell interferon-gamma response, which may play a role in regulating immune-related characteristics. In summary, we concluded that EDA may be used as a new therapeutic CAFs marker for GC.

Protein biomarker signature in patients with spinal and bulbar muscular atrophy

Spinal and bulbar muscular atrophy (SBMA) is a slowly progressing disease with limited sensitive biomarkers that support clinical research. We analyzed plasma and serum samples from patients with SBMA and matched healthy controls in multiple cohorts, identifying 40 highly reproducible SBMA-associated proteins out of nearly 3,000 measured. These proteins were robustly enriched in gene sets of skeletal muscle expression and processes related to mitochondria and calcium signaling. Many proteins outperformed currently used clinical laboratory tests (e.g., creatine kinase [CK]) in distinguishing patients from controls and in their correlations with clinical and functional traits in patients. Two of the 40 proteins, Ectodysplasin A2 receptor (EDA2R) and Repulsive guidance molecule A (RGMA), were found to be associated with decreased survival and body weight in a mouse model of SBMA. In summary, we identified what we believe to be a robust and novel set of fluid protein biomarkers in SBMA that are linked with relevant disease features in patients and in a mouse model of disease. Changes in these SBMA-associated proteins could be used as an early predictor of treatment effects in clinical trials.

Expression of Congenital Anomalies of the Kidney and Urinary Tract (CAKUT) Candidate Genes EDA2R, PCDH9, and TRAF7 in Normal Human Kidney Development and CAKUT

Approximately half of the cases of chronic kidney disease (CKD) in childhood are caused by congenital anomalies of the kidney and urinary tract (CAKUT). Specific genes were identified as having significant importance in regard to the underlying genetic factors responsible for the CAKUT phenotype, and in our research, we focused on analyzing and comparing the expression levels of ectodysplasin A2 receptor (EDA2R), protocadherin9 (PCDH9), and TNF receptor-associated factor 7 (TRAF7) proteins in the cortex and medulla of healthy control kidneys during developmental phases 2, 3, and 4. We also performed an analysis of the area percentages of the mentioned proteins in the cortical and medullary sections of healthy embryonic and fetal kidneys compared to those affected by CAKUT, including duplex kidneys (DK), horseshoe kidneys (HK), hypoplastic kidneys (HYP), and dysplastic kidneys (DYS). We found that the CAKUT candidate gene proteins EDA2R, PCDH9, and TRAF7 are all expressed during normal human kidney development stages. In DYS, the expression of EDA2R was higher than in normal kidneys, likely due to EDA2R's role in apoptosis, which was upregulated in specific cases and could possibly contribute to the formation of DYS. The expression of PCDH9 was lower in HK, which can be attributed to the possible role of PCDH9 in cell migration suppression. Decreased PCDH9 expression is linked to increased cell migration, potentially contributing to the development of HK. The level of TRAF7 expression was reduced in all examined kidney disorders compared to normal kidneys, suggesting that this reduction might be attributed to the crucial role of TRAF7 in the formation of endothelium and ciliogenesis, both of which are essential for normal kidney development. Further research is required to ascertain the function of these proteins in both the typical development of the kidney and in CAKUT.

Ectodysplasin A2 receptor signaling in skeletal muscle pathophysiology

Skeletal muscle is essential in generating mechanical force and regulating energy metabolism and body temperature. Pathologies associated with muscle tissue often lead to impaired physical activity and imbalanced metabolism. Recently, ectodysplasin A2 receptor (EDA2R) signaling has been shown to promote muscle loss and glucose intolerance. Upregulated EDA2R expression in muscle tissue was associated with aging, denervation, cancer cachexia, and muscular dystrophies. Here, we describe the roles of EDA2R signaling in muscle pathophysiology, including muscle atrophy, insulin resistance, and aging-related sarcopenia. We also discuss the EDA2R pathway, which involves EDA-A2 as the ligand and nuclear factor (NF)κB-inducing kinase (NIK) as a downstream mediator, and the therapeutic potential of targeting these proteins in the treatment of muscle wasting and metabolic dysfunction.

Eight EDA mutations in Chinese patients with tooth agenesis and genotype-phenotype analysis

OBJECTIVE

Tooth agenesis is a common craniofacial malformation, which is often associated with gene mutations. The purpose of this research was to investigate and uncover ectodysplasin A (EDA) gene variants in eight Chinese families affected with tooth agenesis.

METHODS

Genomic DNA was extracted from tooth agenesis families and sequenced using whole-exome sequencing. The expression of ectodysplasin A1 (EDA1) protein was studied by western blot, binding activity with receptor was tested by pull-down and the NF-κB transcriptional activity was analyzed by Dual luciferase assay.

RESULTS

Eight EDA missense variants were discovered, of which two (c.T812C, c.A1073G) were novel. The bioinformatics analysis indicated that these variants might be pathogenic. The tertiary structure analysis revealed that these eight variants could cause structural damage to EDA proteins. In vitro functional studies demonstrated that the variants greatly affect protein stability or impair the EDA-EDAR interaction; thereby significantly affecting the downstream NF-κb transcriptional activity. In addition, we summarized the genotype-phenotype correlation caused by EDA variants and found that EDA mutations leading to NSTA are mostly missense mutations located in the TNF domain.

CONCLUSION

Our results broaden the variant spectrum of the EDA gene associated with tooth agenesis and provide valuable information for future genetic counseling.

Identification of six novel mutations in EDA from 20 hypohidrotic ectodermal dysplasia families

OBJECTIVE

To investigate the genetic causes of 22 patients with clinically high suspicion of X-linked hypohidrotic ectodermal dysplasia from 20 unrelated Chinese families, expand the spectrum of ectodysplasin-A mutations, and provide more evidence for variants of uncertain significance.

SUBJECTS AND METHODS

Whole-exome sequencing was performed and potentially pathogenic variants were verified by Sanger sequencing. Western blotting, real-time PCR and immunofluorescence analyses were performed to investigate the preliminary functions of the candidate variants.

RESULTS

Nineteen ectodysplasin-A variants were identified, six of which were not previously reported. Among these variants, we identified a patient who carried two mutations in ectodysplasin-A and exhibited more severe phenotypes. Additionally, mutant protein expression levels decreased, whereas mRNA transcription levels increased. Cellular sublocalisation of the variants located in the tumour necrosis factor homologous domain showed that the proteins accumulated in the nucleus, whereas wild-type proteins remained in the cell membrane. A rare indel variant and two classical splicing variants that lead to exon 7 skipping were detected.

CONCLUSIONS

This study provides definitive diagnoses for 20 families with suspected X-linked hypohidrotic ectodermal dysplasia and additional information on clinical heterogeneity and genotype-phenotype relationships.

Orthodontic Treatment of Palatally Impacted Canines in Severe Non-Syndromic Oligodontia with the Use of Mini-Implants: A Case Report

Background: The risk of palatally displaced canines (PDCs) rises in patients with tooth agenesis. The orthodontic extrusion and alignment of PDCs require adequate anchorage to enable tooth movement and control the side effects. There is no paper presenting treatment in the case of severe oligodontia with simultaneous PDCs and the use of mini-implants (MIs) for their orthodontic extrusion. Case presentation: A 15-year-old patient presented with non-syndromic oligodontia and bilateral PDCs. Cone beam computed tomography revealed that both PDCs were in proximity to the upper incisors' roots. There was no evident external root resorption of the incisors. The "canines first" approach was chosen. MIs were used both as direct and indirect anchorage. First, the extrusive forces of cantilevers were directed both occlusally and distally. Next, the buccal directions of forces were implemented. Finally, fixed appliances were used. PDCs were extruded, aligned, and torqued. Proper alignment and occlusion were achieved to enable further prosthodontic restorations. Conclusions: The use of MIs made it possible to avoid collateral effects, reduce the risk of complications, and treat the patient effectively. MIs provide adequate anchorage in demanding cases. The use of MIs for the extrusion of PDCs made it possible to offer this treatment option to patients with severe oligodontia. The presented protocol was effective and served to circumvent treatment limitations associated with an inadequate amount of dental anchorage and a high risk of root resorption.

Molecular basis and genetics of hypohidrotic ectodermal dysplasias

Ectodermal dysplasia (ED) is a heterogeneous group of hereditary diseases of the skin and its appendages, which are characterized by impaired development and/or homeostasis of two or more ectoderm derivatives, including: hair, teeth, nails, sweat glands and their modifications (mammary glands, for instance). The overall prevalence of ectodermal dysplasia remains precisely unknown not only in Russia, but also in the world, nor is known the contribution of individual genes to its structure. This complicates the DNA diagnosis establishment of this disease due to the lack of an accurate diagnostic algorithm and a universal cost-effective method of analysis. To date, the most highly-researched genes involved in the development of anhydrous or hypohidrotic forms of ED are EDA, EDAR, EDARADD and WNT10A. The ectodysplasin A (EDA) gene is the cause of the most common X-linked form of ED, a gene from the Wnt family (WNT10A) is responsible for the autosomal recessive form of the disease, and two other genes (EDAR and EDARADD) can cause both autosomal recessive and autosomal dominant forms. This review provides the characteristics of the genes involved in ED, their mutation spectra, the level of their expression in human tissues, as well as the interrelation of the aforementioned genes. The domain structures of the corresponding proteins are considered, as well as the molecular genetic pathways in which they are involved. Animal models for studying this disorder are also taken into consideration. Due to the cross-species genes conservation, their mutations cause the disruption of the development of ectoderm derivatives not only in humans, but also in mice, cows, dogs, and even fish. It can be exploited for a better understanding of the etiopathogenesis of ectodermal dysplasias. Moreover, this article brings up the possibility of recurrent mutations in the EDA and WNT10A genes. The review also presents data on promising approaches for intrauterine ED treatment.

Plasma levels of neurology-related proteins are associated with cognitive performance in an older population with overweight/obesity and metabolic syndrome

Cognitive impairment is present in a broad spectrum of medical conditions and in aging. Here, we aimed to identify plasma proteins related to cognitive function in a sample of older adults with overweight/obesity and metabolic syndrome. A total of 129 subjects (mean age 64.7 years; 36% females) were grouped according to low (l-GCF, N=65) or high (h-GCF, N=64) global cognitive function and matched according to education, sex, age, and body mass index. Cognitive performance was assessed using neuropsychological tests. Plasma levels of 92 neurology-related proteins were assessed using a proximity extension assay. An elastic net regression analysis was used to identify proteins more associated with cognitive performance. Additionally, the protein expression levels were compared between the two groups by means of a t-test with false discovery rate correction. Pearson correlations were used to assess associations between the protein levels and scores from the neurocognitive tests. Six proteins (alpha-2-MRAP, HAGH, Siglec-9, MDGA1, IL12, and EDA2R) were identified as potential contributors to cognitive performance, remaining significantly increased in l-GCF compared to h-GCF participants after correction for multiple testing. Negative correlations (r= -0.23 to -0.18, i.e., lower protein levels, higher cognitive function) were found between global cognitive function and Siglec-9, NMNAT1, HAGH, LXN, gal-8, alpha-2-MRAP, IL12, PDGF-R-alpha, NAAA, EDA2R, CLEC1B, and LAT. Mini-mental state examination z scores showed the strongest correlations with protein levels, specifically negative correlations with CLEC1b, LXN, LAT, PLXNB3, NMNAT1, gal-8, HAGH, NAAA, CTSS, EZR, KYNU, MANF (r=-0.38 to -0.26) and a positive correlation with ADAM23 (r= 0.26). In summary, we identified several plasma proteins that were significantly associated with cognitive performance in older adults with obesity and metabolic syndrome, although further research is needed to replicate the results in larger samples and to include a predictive perspective.

X-Linked Hypohidrotic Ectodermal Dysplasia (XLHED): A Case Report and Overview of the Diagnosis and Multidisciplinary Modality Treatments

Hypohidrotic ectodermal dysplasia (HED) is a rare genetic disorder caused by a mutation in either the ectodysplasin (EDA), ectodysplasin A receptor (EDAR), EDAR associated via death domain (EDARADD), or Wnt family member 10A (WNT10A) genes that result in impaired development of ectodermal-derived structures. The literature defines two types of ectodermal dysplasia, which are hypohidrotic and hidrotic. X-linked hypohidrotic ectodermal dysplasia (XLHED), also known as Christ-Siemens-Touraine syndrome, is the most common form and is a variant of ectodermal dysplasia characterized by a classical triad of hypo/adontia, hypohidrosis, and hypotrichosis; whereas, hidrotic type of ectodermal dysplasia, also known as Clouston syndrome, is characterized by a triad of onychodysplasia, hypotrichosis, and palmoplantar hyperkeratosis while sparing the sweat glands. Symptoms of XLHED can begin early in life between the ages of one month to 23 months. XLHED is more commonly seen in males due to the x-linked characteristics of the gene mutations. This disease can be diagnosed by physical exam alone, or in combination with molecular genetic testing. XLHED specifically has an estimated occurrence of one in every 20,000 newborns worldwide. Approximately 5,000 people in the United States have the disease.  In this case report, we present an adult patient diagnosed with XLHED. Our objective is to emphasize the significance of early diagnosis, advocate for a multidisciplinary management approach, and shed light on the potential of recombinant protein and targeted gene therapy for further research. By raising awareness of this condition, we aim to improve patient outcomes not only in newborns but also in adults who have already been diagnosed with XLHED.

Decay of Skin-Specific Gene Modules in Pangolins

The mammalian skin exhibits a rich spectrum of evolutionary adaptations. The pilosebaceous unit, composed of the hair shaft, follicle, and the sebaceous gland, is the most striking synapomorphy. The evolutionary diversification of mammals across different ecological niches was paralleled by the appearance of an ample variety of skin modifications. Pangolins, order Pholidota, exhibit keratin-derived scales, one of the most iconic skin appendages. This formidable armor is intended to serve as a deterrent against predators. Surprisingly, while pangolins have hair on their abdomens, the occurrence of sebaceous and sweat glands is contentious. Here, we explore various molecular modules of skin physiology in four pangolin genomes, including that of sebum production. We show that genes driving wax monoester formation, Awat1/2, show patterns of inactivation in the stem pangolin branch, while the triacylglycerol synthesis gene Dgat2l6 seems independently eroded in the African and Asian clades. In contrast, Elovl3 implicated in the formation of specific neutral lipids required for skin barrier function is intact and expressed in the pangolin skin. An extended comparative analysis shows that genes involved in skin pathogen defense and structural integrity of keratinocyte layers also show inactivating mutations: associated with both ancestral and independent pseudogenization events. Finally, we deduce that the suggested absence of sweat glands is not paralleled by the inactivation of the ATP-binding cassette transporter Abcc11, as previously described in Cetacea. Our findings reveal the sophisticated and complex history of gene retention and loss as key mechanisms in the evolution of the highly modified mammalian skin phenotypes.

A novel EDAR variant identified in non-syndromic tooth agenesis: Insights from molecular dynamics

OBJECTIVE

This study aims to investigate a novel pathogenic variant in a Chinese family of non-syndromic tooth agenesis (NSTA) and study the impact of the variant on related protein and pathway.

DESIGN

One NSTA family was collected. Whole exome sequencing and Sanger sequencing were performed on the proband with NSTA and his 5 family members. The pathogenic influence of the mutant is evaluated by bioinformatics analyses including evolutionary conservation analysis and secondary structure prediction. Molecular dynamics (MD) simulations and binding free energy calculations were then performed to explore changes in the tertiary structure and binding ability of the protein.

RESULTS

We found a novel missense ectodysplasin A receptor (EDAR) variant (c .1292 T > G; p.Ile431Arg) in all affected family members. The results of bioinformatics analyses revealed that the EDAR had harmful changes after mutation. MD simulations and the binding free energy calculations results showed that the mutant EDAR protein and EDAR/ectodysplasin-A receptor-associated adapter (EDARADD) complex displayed tertiary structural change, and EDAR possessed a lower affinity to EDARADD after mutation.

CONCLUSIONS

We found a novel EDAR variant (c.1292 T > G; p.Ile431Arg) in one NSTA family, which affects the binding of EDAR and EDARADD.

Ectodysplasin A (EDA) Signaling: From Skin Appendage to Multiple Diseases

Ectodysplasin A (EDA) signaling is initially identified as morphogenic signaling regulating the formation of skin appendages including teeth, hair follicles, exocrine glands in mammals, feathers in birds and scales in fish. Gene mutation in EDA signaling causes hypohidrotic ectodermal dysplasia (HED), a congenital hereditary disease with malformation of skin appendages. Interestingly, emerging evidence suggests that EDA and its receptors can modulate the proliferation, apoptosis, differentiation and migration of cancer cells, and thus may regulate tumorigenesis and cancer progression. More recently, as a newly discovered hepatocyte factor, EDA pathway has been demonstrated to be involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and type II diabetes by regulating glucose and lipid metabolism. In this review, we summarize the function of EDA signaling from skin appendage development to multiple other diseases, and discuss the clinical application of recombinant EDA protein as well as other potential targets for disease intervention.