Mutations in AEC syndrome skin reveal a role for p63 in basement membrane adhesion, skin barrier integrity and hair follicle biology
ABSTRACT AEC (ankyloblepharon-ectodermal defects-clefting) syndrome is an autosomal dominant ectodermal dysplasia disorder caused by mutations in the transcription factor p63. Clinically, the skin is dry and often fragile; other features can include partial eyelid fusion (ankyloblepharon), hypodontia, orofacial clefting, sparse hair or alopecia, and nail dystrophy.
To investigate how p63 gene mutations affect gene and protein expression in AEC syndrome skin.
We performed microarray analysis on samples of intact and eroded AEC syndrome skin compared with control skin. Changes were verified by quantitative real-time reverse transcription-polymerase chain reaction and, for basal keratinocyte-associated genes, by immunohistochemistry and analysis of microdissected skin.
We identified significant upregulation of six genes and downregulation of 69 genes in AEC syndrome skin, with the main changes in genes implicated in epidermal adhesion, skin barrier formation and hair follicle biology. There was reduced expression of genes encoding the basement membrane proteins FRAS1 and collagen VII, as well as the skin barrier-associated small proline-rich proteins 1A and 4, late cornified envelope protein 5A, hornerin, and lipid transporters including ALOX15B. Reduced expression of the hair-associated keratins 25, 27, 31, 33B, 34, 35, 81 and 85 was also noted. We also confirmed similar alterations in gene expression for 26 of the 75 genes in eroded AEC scalp skin.
This study identifies specific changes in skin structural biology and signalling pathways that result from mutant p63 and provides new molecular insight into the AEC syndrome phenotype.
SourceAvailable from: PubMed Central
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ABSTRACT: Hay-Wells syndrome or AEC (Ankyloblepharon, Ectodermal dysplasia and Cleft lip and palate syndrome) is a rare ectodermal disorder. The treatment is aimed to prevent clinical complications. We describe the case of a four-month old male patient with erosions on the scalp, trunk and arms, trachyonychia, deformity of the ears, micropenis, cleft palate, decreased eyebrow and eyelash hairs, in addition to antecedents of surgical correction of ankyloblepharon. The importance of the correct diagnosis is emphasized, besides the investigation of the associated diseases, treatment of complications and genetic counseling of the parents.Anais brasileiros de dermatologia 04/2014; 89(2):363-4. DOI:10.1590/abd1806-4841.20142806
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ABSTRACT: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome is a rare monogenetic disorder that is characterized by severe abnormalities in ectoderm-derived tissues, such as skin and its appendages. A major cause of morbidity among affected infants is severe and chronic skin erosions. Currently, supportive care is the only available treatment option for AEC patients. Mutations in TP63, a gene that encodes key regulators of epidermal development, are the genetic cause of AEC. However, it is currently not clear how mutations in TP63 lead to the various defects seen in the patients' skin. In this review, we will discuss current knowledge of the AEC disease mechanism obtained by studying patient tissue and genetically engineered mouse models designed to mimic aspects of the disorder. We will then focus on new approaches to model AEC, including the use of patient cells and stem cell technology to replicate the disease in a human tissue culture model. The latter approach will advance our understanding of the disease and will allow for the development of new in vitro systems to identify drugs for the treatment of skin erosions in AEC patients. Further, the use of stem cell technology, in particular induced pluripotent stem cells (iPSC), will enable researchers to develop new therapeutic approaches to treat the disease using the patient's own cells (autologous keratinocyte transplantation) after correction of the disease-causing mutations. © 2014 Wiley Periodicals, Inc.American Journal of Medical Genetics Part A 10/2014; 164(10). DOI:10.1002/ajmg.a.36455 · 2.05 Impact Factor
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ABSTRACT: Nectins are immunoglobulin-like cell adhesion molecules mainly localized in adherens junctions. The transcription factor p63 is a master regulator of gene expression in stratified epithelia and controls several molecular processes. Since mutations in the Pvrl1 and Pvrl4 genes encoding for nectins cause genetic disorders with phenotypes similar to p63-related syndromes, we investigated whether these proteins might be under p63 transcriptional control. Here we show that in p63-null skin Pvrl1 gene expression is strongly reduced, whereas Pvrl4 expression is unaffected. In human and mouse primary keratinocytes p63 depletion leads to a specific downregulation of the Pvrl1 gene. Consistent with a direct regulation, Chromatin Immunoprecipitation experiments (ChIP) indicate that p63 binds to two conserved intronic Pvrl1 enhancer regions. AEC syndrome is a rare autosomal dominant disorder, caused by mutations in p63 gene, mainly characterized by skin fragility. To test whether nectins may be affected in AEC syndrome, their expression was measured in keratinocytes obtained from AEC patients or from a conditional mouse model for AEC syndrome. Pvrl1 expression was reduced in AEC keratinocytes, consistent with impaired p63 function. Surprisingly Pvrl4 expression was similarly affected, in parallel with decreased expression of the transcription factor Irf6. Consistent with the well-characterized role of Irf6 in keratinocyte differentiation and its strong downregulation in AEC syndrome, Irf6 depletion caused reduced expression of Pvrl4 in wild-type keratinocytes. Taken together our results indicate that Pvrl1 is a bona fide target gene of the transcription factor p63, whereas Pvrl4 regulation is linked to epidermal differentiation and is under Irf6 control. This article is protected by copyright. All rights reserved.Experimental Dermatology 11/2014; 24(2). DOI:10.1111/exd.12593 · 4.12 Impact Factor