French national protocol for the management of congenital ichthyosis.

Congenital ichthyoses (CI) comprise a heterogeneous group of monogenic genetic skin diseases characterized by diffuse scaling, often associated with skin inflammation. Diagnosis of the individual form of ichthyosis is complex and is guided by clinical expertise. CI usually has a major impact on quality of life (QOL) and thus requires lifelong treatment. To date, there are no curative therapies, although various symptomatic treatment options exist. The present protocol for the management of CI has been drawn up in accordance with the recommendations published in 2012 by the French National Authority for Health, based on a literature review, with the help and validation of members of the French network for rare skin diseases (FIMARAD). It provides a summary of evidence and expert-based recommendations and is intended to help clinicians with the management of these rare and often complex diseases.

New developments in the molecular treatment of ichthyosis: review of the literature.

Ichthyosis covers a wide spectrum of diseases affecting the cornification of the skin. In recent years, new advances in understanding the pathophysiology of ichthyosis have been made. This knowledge, combined with constant development of pathogenesis-based therapies, such as protein replacement therapy and gene therapy, are rather promising for patients with inherited skin diseases. Several ongoing trials are investigating the potency of these new approaches and various studies have already been published. Furthermore, a lot of case series report that biological therapeutics are effective treatment options, mainly for Netherton syndrome and autosomal recessive congenital ichthyosis. It is expected that some of these new therapies will prove their efficacy and will be incorporated in the treatment of ichthyosis.

Management of congenital ichthyoses: European guidelines of care, part two.

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016, and a consensus on the discussions. These guidelines summarize evidence and expert-based recommendations and intend to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part two, covering the management of complications and the particularities of some forms of congenital ichthyosis.

Management of congenital ichthyoses: European guidelines of care, part one.

These guidelines for the management of congenital ichthyoses have been developed by a multidisciplinary group of European experts following a systematic review of the current literature, an expert conference held in Toulouse in 2016 and a consensus on the discussions. They summarize evidence and expert-based recommendations and are intended to help clinicians with the management of these rare and often complex diseases. These guidelines comprise two sections. This is part one, covering topical therapies, systemic therapies, psychosocial management, communicating the diagnosis and genetic counselling.

[Ichthyosis prematurity syndrome: Two new cases]. / Le syndrome « ichtyose-prématurité ¼ : deux nouveaux cas.

BACKGROUND: Ichthyosis prematurity syndrome is a rare syndromic form of ichthyosis caused by mutations in FATP4, which plays a central role in the transport and activation of fatty acids in the epidermis and in epidermal barrier function. Despite stereotypical clinical presentation in the neonatal period, the diagnosis is not well known by clinicians. Herein we report two new cases. PATIENTS AND METHODS: Case no. 1: a boy born prematurely (33weeks of gestation) to non-consanguineous French parents presented at birth with respiratory distress necessitating admission to intensive care. His skin was covered by a thick caseous vernix, especially on the scalp, eyebrows and 4 limbs. At the age of 4years, the boy's skin appeared normal. Case no. 2: a boy born prematurely to consanguineous Moroccan parents (34weeks of gestation) presented at birth with respiratory distress requiring admission to intensive care. At clinical examination, he had a whitish thick skin giving an impression of vernix caseosa, with involvement of the scalp, forehead, 4 limbs and abdomen. At the age of 2 years, his skin was normal. CONCLUSION: The clinical presentation of this syndrome is typical. It is important to make the diagnosis to enable genetic counseling and planning of adequate neonatal care in the event of future pregnancies.

Novel mutation in NIPAL4 in a Romanian family with autosomal recessive congenital ichthyosis.

Autosomal recessive congenital ichthyosis (ARCI), a severe and highly clinically heterogeneous group of mendelian disorders of cornification, is the result of mutations in at least nine genes regulating the epidermal barrier functionality. NIPAL4 is the second most frequently mutated ARCI gene. We report two adult patients from a nonconsanguineous family of Romanian origin, who had lamellar ichthyosis. A positive in situ transglutaminase 1 activity assay excluded a putative TGM1 mutation. NIPAL4 sequencing revealed in both patients a new homozygous missense mutation, c.403A>C, affecting a highly conserved amino acid (p. Ser135Arg) and predicted to be deleterious according to in silico analysis. In addition to the ARCI features, the patients had caries and partial edentation. Although delay in dental treatment led to caries progression and extraction of secondary teeth, this finding raises the possibility of a deficiency in enamel mineralization due to NIPAL4 dysfunction as an Mg(2+) transporter. Evaluating new patients with ARCI provides fruitful clinical and molecular findings.

Identification of the first nonsense CDSN mutation with expression of a truncated protein causing peeling skin syndrome type B.

BACKGROUND: Peeling skin disease (PSD), a generalized inflammatory form of peeling skin syndrome, is caused by autosomal recessive nonsense mutations in the corneodesmosin gene (CDSN). OBJECTIVES: To investigate a novel mutation in CDSN. METHODS: A 50-year-old white woman showed widespread peeling with erythema and elevated serum IgE. DNA sequencing, immunohistochemistry, Western blot and real-time polymerase chain reaction analyses of skin biopsies were performed in order to study the genetics and to characterize the molecular profile of the disease. RESULTS: Histology showed hyperkeratosis and acanthosis of the epidermis, and inflammatory infiltrates in the dermis. DNA sequencing revealed a homozygous mutation leading to a premature termination codon in CDSN: p.Gly142*. Protein analyses showed reduced expression of a 16-kDa corneodesmosin mutant in the upper epidermal layers, whereas the full-length protein was absent. CONCLUSIONS: These results are interesting regarding the genotype-phenotype correlations in diseases caused by CDSN mutations. The PSD-causing CDSN mutations identified heretofore result in total corneodesmosin loss, suggesting that PSD is due to full corneodesmosin deficiency. Here, we show for the first time that a mutant corneodesmosin can be stably expressed in some patients with PSD, and that this truncated protein is very probably nonfunctional.

Alterations in the desquamation-related proteolytic cleavage of corneodesmosin and other corneodesmosomal proteins in psoriatic lesional epidermis.

BACKGROUND: Desquamation occurs after proteolysis of corneodesmosomal proteins, including corneodesmosin (CDSN), by proteases of the kallikrein family, particularly KLK7. Impaired desquamation is one of the features of psoriasis, and psoriasis-associated single nucleotide polymorphisms of the CDSN gene may potentially modify the proteolysis of the encoded protein. OBJECTIVES: To test whether the proteolysis of CDSN and other corneodesmosomal components is altered in psoriatic epidermis. METHODS: Total protein extracts obtained by tape-stripping of nonlesional and lesional skin from 11 patients were compared by immunoblotting experiments. RESULTS: An almost intact form of CDSN that has never been observed previously in the normal upper stratum corneum was detected in the lesional skin extracts, showing an altered proteolytic processing of the protein. This form was also observed in the nonlesional skin extracts, but in lower amounts. For most patients, increased amounts of desmoglein 1, plakoglobin and of high molecular weight fragments of desmocollin 1 were detected in the lesional skin. For most of them, similar amounts of KLK7 were immunodetected in both nonlesional and lesional skin extracts. No particular differences were observed related to the psoriasis type, the HLA-Cw6 status of the patients or any particular CDSN polymorphisms. CONCLUSIONS: We detected a near full-length form of CDSN that has not been previously observed in normal stratum corneum. The results suggest a reduced degradation of all corneodesmosomal proteins in psoriatic lesions which probably reflects the persistence of corneodesmosomes.

Refined characterization of corneodesmosin proteolysis during terminal differentiation of human epidermis and its relationship to desquamation.

Corneodesmosin is a putative adhesion glycoprotein located in the extracellular part of the desmosomes in the upper layers of the epidermis. Synthesized by granular keratinocytes as a 52-56-kDa protein, corneodesmosin is progressively proteolysed during corneocyte maturation. This processing is a prerequisite for desquamation. Two glycine- and serine-rich domains of the protein might take on the conformation of adhesive secondary structures similar to glycine loops. Corneodesmosin proteolysis was further characterized. Deglycosylation experiments and reactivity with lectins demonstrated that the corneodesmosin carbohydrate moiety does not prevent the proteolysis. Immunoblotting, immunohistochemistry, and immunoelectron microscopy experiments using affinity-purified anti-peptide antibodies raised to four of the five structural domains of corneodesmosin and a monoclonal antibody against its fifth central domain showed that the first step in corneodesmosin processing is the cleavage of its extremities and probably occurs before its incorporation into desmosomes. Then the glycine loop-related domains are cleaved, first the N-terminal and then part of the C-terminal domain. At the epidermis surface, the multistep proteolytic cleavage leaves intact only the central domain, which was detected on exfoliated corneocytes and probably lacks adhesive properties. Importantly, corneodesmosin was demonstrated to be a preferred substrate of two serine proteases involved in desquamation, the stratum corneum tryptic and chymotryptic enzymes.

Upregulation and redistribution of E-MAP-115 (epithelial microtubule-associated protein of 115 kDa) in terminally differentiating keratinocytes is coincident with the formation of intercellular contacts.

Microtubules are involved in the positioning and movement of organelles and vesicles and therefore play fundamental roles in cell polarization and differentiation. Their organization and properties are cell-type specific and are controlled by microtubule-associated proteins (MAP). E-MAP-115 (epithelial microtubule-associated protein of 115 kDa) has been identified as a microtubule-stabilizing protein predominantly expressed in epithelial cells. We have used human skin and primary keratinocytes as a model to assess a putative function of E-MAP-115 in stabilizing and reorganizing the microtubule network during epithelial cell differentiation. Immunolabeling of skin sections indicated that E-MAP-115 is predominantly expressed in the suprabasal layers of the normal epidermis and, in agreement with this observation, is relatively abundant in squamous cell carcinomas but barely detectable in basal cell carcinomas. In primary keratinocytes whose terminal differentiation was induced by increasing the Ca2+ concentration of the medium, E-MAP-115 expression significantly increased during the first day, as observed by northern and western blot analysis. Parallel immunofluorescence studies showed an early redistribution of E-MAP-115 from microtubules with a paranuclear localization to cortical microtubules organized in spike-like bundles facing intercellular contacts. This phenomenon is transient and can be reversed by Ca2+ depletion. Treatment of cells with cytoskeleton-active drugs after raising the Ca2+ concentration indicated that E-MAP-115 is associated with a subset of stable microtubules and that the cortical localization of these microtubules is dependent on other microtubules but not on strong interactions with the actin cytoskeleton or the plasma membrane. The mechanism whereby E-MAP-115 would redistribute to and stabilize cortical microtubules used for the polarized transport of vesicles towards the plasma membrane, where important reorganizations take place upon stratification, is discussed.

The distribution of murine 115-kDa epithelial microtubule-associated protein (E-MAP-115) during embryogenesis and in adult organs suggests a role in epithelial polarization and differentiation.

In interphase cells microtubules play fundamental roles in the intracellular distribution and movement of organelles and vesicles and thereby contribute to cellular polarization and differentiation. The organization of microtubules varies with the cell type and is presumably controlled by tissue-specific microtubule-associated proteins (MAPs). The 115-kDa epithelial MAP (E-MAP-115) has been identified as a microtubule-stabilizing protein predominantly expressed in cell lines of epithelial origin. To assess a putative function of E-MAP-115 in epithelial morphogenesis in vivo, we have cloned the cDNA encoding the murine protein and studied the cellular distribution of E-MAP-115 mRNA and protein during murine embryogenesis and in adult organs. Analysis of the predicted amino acid sequence of murine E-MAP-115 revealed 81% sequence identity with its human homolog, the best-conserved part of the protein being the microtubule-binding site. Our data indicate that E-MAP-115 is expressed in several epithelia from 9.5 days of embryogenesis onwards and that its expression levels increase during development. From 14.5 days onwards, E-MAP-115 mRNA is found in some neuronal cells as well. In adult organs, E-MAP-115 is most abundant in epithelial cells of kidney tubules, in absorptive cells of the intestine and is widely distributed in the testis. E-MAP-115 expression correlates with the differentiation of certain epithelial cell types: in the adult intestine, for example, E-MAP-115 mRNA and protein are more abundant in the differentiating than in the proliferative cell compartment. Moreover, E-MAP-115 expression clearly correlates with the degree of cellular apicobasal polarity. In the developing kidney, E-MAP-115 mRNA is detected in the cuboidal cells of S-shaped bodies, of primitive tubules and glomerula, whereas, E-MAP-115 mRNA and protein are absent from mature podocytes which have lost their initial apico-basal polarity. The pattern of distribution of E-MAP-115 in vivo is so far unique for a MAP. Taken together, our results provide support for a role of E-MAP-115 in reorganizing the microtubule cytoskeleton during epithelial cell polarization and differentiation.

Herpes simplex virus Us11 protein enhances recovery of protein synthesis and survival in heat shock treated HeLa cells.

One of the herpes simplex virus type 1 (HSV-1) true late gene products, Us11 protein, is brought into the cell by the infecting virion and may play a role in the virally-induced post-transcriptional control of gene expression. Us11 protein forms large oligomers, exhibits RNA binding features, concentrates into the nucleolus and is able to replace Rex protein in post-transcriptional control of human T-cell leukemia/lymphoma virus type I (HTLV-I) expression. As heat shock drastically alters protein synthesis, and because HSV-1 infection stimulates heat shock protein (Hsp) expression, we analyzed the consequence of heat shock in HeLa cells expressing Us11 alone, either transiently or constitutively. No detectable modification of the overall pattern of protein synthesis was observed in cells growing at normal temperatures, including no induction of Hsp expression or accumulation. However, Us11 protein expression induced an enhanced recovery of protein synthesis after heat shock. Moreover, the level of Us11 protein-mediated protection of protein synthesis was similar to that observed for cells made thermotolerant, but only when submitted to a mild heat shock. Finally, Us11 protein expression induced in cells an enhanced survival to heat shock.

Transformation by T-antigen and other oncogenes delays Hsp25 accumulation in heat shocked NIH 3T3 fibroblasts.

We have recently reported that transformation of murine NIH 3T3 cells by v-fos oncogene interfered with Hsp70 and Hsp25 accumulation after heat shock. Here, we have investigated the effect mediated by other oncogenes on the accumulation of these stress proteins. We report that T-antigen transformation of NIH 3T3 cells delayed and reduced the accumulation of Hsp25 after heat shock and decreased the heat-mediated phosphorylation of this protein. This decreased level of Hsp25 correlated with a reduced accumulation of the corresponding mRNA and was related to T-antigen level. In contrast, T-antigen had no effect on the expression of the major stress protein Hsp70 nor did it interfere with the level of Hsp90 or Hsp60. We report also that v-src or Ha-ras oncogenes delayed Hsp25 accumulation after heat shock but that only v-src reduced the heat-induced phosphorylation of this protein. v-src, but not Ha-ras, interfered with Hsp70 expression and none of these oncogenes had an effect on Hsp60 or Hsp90 levels. Taken together, these observations suggest that an altered accumulation of Hsp25 after heat shock is a common characteristic of NIH 3T3 fibroblasts transformed by different oncogenes.