Biomedical subjects

Marek Haftek

Publications and source records attributed to Marek Haftek.

6 recordsLinked to original sources

PubMed2004

Hailey-Hailey disease: identification of novel mutations in ATP2C1 and effect of missense mutation A528P on protein expression levels.

ATP2C1, encoding the human secretory pathway Ca(2+)-ATPase (hSPCA1), was recently identified as the defective gene in Hailey-Hailey disease (HHD), an autosomal dominant skin disorder characterized by abnormal keratinocyte adhesion in the suprabasal layers of the epidermis. In this study, we used denaturing high-performance liquid chromatography to screen all 28 exons and flanking intron boundaries of ATP2C1 for mutations in 9 HHD patients. Nine different mutations were identified. Five of these mutations, including one nonsense, one deletion, two splice-site, and one missense mutation, have not been previously reported. Recently, functional analysis of a series of site-specific mutants, designed to mimic missense mutations found in ATP2C1, uncovered specific defects in Ca(2+) and/or Mn(2+) transport and protein expression in mutant hSPCA1 polypeptides. In order to investigate the molecular and physiological basis of HHD in the patient carrying missense mutation A528P, located in the putative nucleotide binding domain of the molecule, site-directed mutagenesis was employed to introduce this mutation into the wild-type ATP2C1 (hSPCA1) sequence. Functional analyses of HHD-mutant A528P demonstrated a low level of protein expression, despite normal levels of mRNA and correct targeting to the Golgi, suggesting instability or abnormal folding of the mutated hSPCA1 polypeptides. Analogous to conclusions drawn from our previous studies, these results further support the theory of haploinsufficiency as a prevalent mechanism for the dominant inheritance of HHD, by suggesting that the level of hSPCA1 in epidermal cells is critical.

Amino Acid Sequence↗

PubMed2004

Functional consequences of a neutral pH in neonatal rat stratum corneum.

At birth, neonatal stratum corneum (SC) pH is close to neutral but acidifies with maturation, which can be ascribed, in part, to secretory phospholipase A(2) and sodium/hydrogen antiporter 1 (NHE1) activities. Here we assessed the functional consequences of a neutral SC pH in a newborn rat model. While basal transepidermal water loss rates are near normal, barrier recovery (BR) rates after acute barrier disruption were delayed in newborn animals. The abnormality in barrier homeostasis could be improved by topical applications of an acidic buffer, indicating that barrier abnormality is primarily due to high SC pH. The delay in BR correlated with incompletely processed lamellar membranes and decreased activity of beta-glucocerebrosidase. Inhibition of NHE1 delayed BR after acute barrier perturbation. SC integrity was abnormal in newborn animals. Electron microscopy demonstrated decreased corneodesmosomes (CD) in newborn animals with decreased expression of desmoglein 1 and corneodesmosin. Serine protease activation appears to be responsible for CD degradation in newborn animals, because serine protease activity is increased in the SC and it can be reduced by acidification of the SC. The delay in acidification of neonatal SC results in abnormalities in permeability barrier homeostasis and SC integrity and are likely due to pH-induced modulations in enzyme activity.

Acids↗

PubMed2003

Skin lipids.

Explore the source record for details and available documents.

Adipocytes↗

PubMed2003

Topical ascorbic acid on photoaged skin. Clinical, topographical and ultrastructural evaluation: double-blind study vs. placebo.

Vitamin C is known for its antioxidant potential and activity in the collagen biosynthetic pathway. Photoprotective properties of topically applied vitamin C have also been demonstrated, placing this molecule as a potential candidate for use in the prevention and treatment of skin ageing. A topically applied cream containing 5% vitamin C and its excipient were tested on healthy female volunteers presenting with photoaged skin on their low-neck and arms in view to evaluate efficacy and safety of such treatment. A double-blind, randomized trial was performed over a 6-month period, comparing the action of the vitamin C cream vs. excipient on photoaged skin. Clinical assessments included evaluation at the beginning and after 3 and 6 months of daily treatment. They were performed by the investigator and compared with the volunteer self assessment. Skin relief parameters were determined on silicone rubber replicas performed at the same time-points. Cutaneous biopsies were obtained at the end of the trial and investigated using immunohistochemistry and electron microscopy. Clinical examination by a dermatologist as well as self-assessment by the volunteers disclosed a significant improvement, in terms of the 'global score', on the vitamin C-treated side compared with the control. A highly significant increase in the density of skin microrelief and a decrease of the deep furrows were demonstrated. Ultrastructural evidence of the elastic tissue repair was also obtained and well corroborated the favorable results of the clinical and skin surface examinations. Topical application of 5% vitamin C cream was an effective and well-tolerated treatment. It led to a clinically apparent improvement of the photodamaged skin and induced modifications of skin relief and ultrastructure, suggesting a positive influence of topical vitamin C on parameters characteristic for sun-induced skin ageing.

Administration, Topical↗

PubMed2003

Alterations in desmosome size and number coincide with the loss of keratinocyte cohesion in skin with homozygous and heterozygous defects in the desmosomal protein plakophilin 1.

Recessive mutations in the desmosomal plaque protein plakophilin 1 (PkP1) underlie ectodermal dysplasia/skin fragility syndrome (MIM 604536). We undertook an immunohistochemical and quantitative electron microscopic examination of suprabasal desmosomes from 4 skin samples from 3 PkP1 deficient patients, an unaffected carrier with a PKP1 heterozygous acceptor splice site mutation and 5 healthy control subjects. Desmosomal plaque size (>50 desmosomes per individual) and frequency (>20 high power fields, HPF) were assessed. Compared with controls, desmosomes were reduced dramatically both in size (49%) and frequency (61%) in the lower suprabasal layers (LSB) in PkP1 null patients (P<0.01). In the LSB compartment of the heterozygous carrier, corresponding reductions were 37% and 20%, respectively (P<0.01). Surprisingly, the PkP1 null patient's upper suprabasal layer, (USB), desmosome size was larger (59%, P<0.01) than the control value, and showed increased desmoglein 1 and PkP2 USB staining. The USB desmosome frequency in PKP1 null patients was similar to the LSB compartment (but reduced by 43% compared to USB controls). The carrier showed no difference in the USB desmosome size and frequency compared with the controls (P>0.05). The PKP1 null patients showed poorly developed inner and outer desmosomal plaques. Thus, both the patients and unaffected carrier showed reductions in the LSB desmosome size and number; despite only PkP1 null patients exhibiting any phenotype. These findings attest to the molecular recruiting and stabilizing roles of PkP1 in desmosome formation, particularly in the LSB compartment.

Adolescent↗

PubMedDate not supplied

Desmosome-binding antibody KM48 recognises an extracellular antigen different from desmosomal cadherins Dsg 1-3 and Dsc 1-3.

Desmosomes are the most prominent and mechanically important epidermal intercellular junctions. Transmembrane proteins of desmosomes, desmogleins and desmocollins, are responsible for extracellular binding and, thus, are important for interkeratinocyte cohesion. We show here, using three different approaches, that the extracellular "cores" of epidermal desmosomes contain a highly glycosylated antigen, different from desmosomal cadherins. This protein, recognised by KM48 monoclonal antibody, is likely to be involved in the processes of keratinocyte differentiation, desmosome turnover and epidermal cohesion.

Animals↗