The influence of sun exposure on the DNA methylation status of <Emphasis Type="Italic">MMP9</Emphasis>, <Emphasis Type="Italic">miR-137</Emphasis>, <Emphasis Type="Italic">KRT14</Emphasis> and <Emphasis Type="Italic">KRT19</Emphasis> genes in human skin

Background

Studies have shown that a variety of environmental factors and habits are associated with epigenetic changes. In addition, various genes are also found to respond to UV radiation.

Objectives

The aim of this study was to investigate the sun exposure influence on the DNA methylation profile on the matrix metalloprotease-9 (MMP9), microRNA 137 (miR-137), cytokeratin 14 (KRT14) and 19 (KRT19) genes of skin cells of subjects with no history of skin diseases.

Methods

Skin biopsies (5mm) were obtained using a punch technique on sun-exposed (outer forearm) and sun-protected areas (inner arm) from 30 corpses from the Brazilian Service of Death Investigation. Skin types were ranked according to Fitzpatrick’s criteria. Genomic DNA was extracted and a DNA methylation analysis was performed using Methylation Specific PCR (MSP) or Methylation-Sensitive Restriction Enzymes (MSRE) of sun-exposed and sun-protected skin areas.

Results

No differences were found among the areas (p>0.05; McNemar), with the partially methylated condition found to be a common event in skin for both MMP9 and miR-137 genes and the methylated condition for both KRT14 and KRT19 genes. Additional analysis showed no differences in the methylation status when age, gender and skin type were considered, however, the methylation status of miR-137 gene seems to be genderrelated.

Conclusions

We conclude that sun exposure does not induce changes in the DNA methylation status in MMP9, miR-137, KRT14 and KRT19 genes.

     

Expression of<Emphasis Type="Italic"> p53</Emphasis>,<Emphasis Type="Italic"> bcl-2</Emphasis> and growth hormone receptor in actinic keratosis,hypertrophic type

According to novel investigations, actinic keratosis (AK) is not a premalignant lesion but is a malignant lesion in the evolution to invasive squamous cell carcinoma (SCC). Thus, we analyzed p53, bcl-2 and growth hormone receptor (GHR) expression in hypertrophic-type AK (HAK) to determine the relative importance of these protooncogenes in the biological behavior of HAK. Expression of p53, bcl-2 and GHR was determined by immunohistochemistry in 33 HAK specimens and surrounding perilesional normal skin (PNS). The relative proportions of immunoreactive cells were determined. Of the 33 HAK specimens, 30 (91%) showed immunopositive staining for p53, 33 (100%) for bcl-2, and 12 (36%) for GHR. Highly positive p53 expression in HAK lesions could indicate that p53 mutation is an early and crucial event in lesion development. The detected pattern of the p53/ bcl-2 ratio in HAK suggests an important role for another gene: the proapoptotic gene bax. Our findings indicate that GHR expression could be a biological marker of progression of HAK to SCC.     

Recurrent mutations in functionally-related <Emphasis Type="Italic">EDA</Emphasis> and <Emphasis Type="Italic">EDAR</Emphasis> genes underlie X-linked isolated hypodontia and autosomal recessive hypohidrotic ectodermal dysplasia

Mutations in three functionally related genes EDA, EDAR and EDARDD have been reported to cause hypohidrotic ectodermal dysplasia (HED), which is characterized by sparse hair, reduced ability to sweat, and hypodontia. In few cases mutations in the EDA gene have been found to result in X-linked recessive isolated hypodontia. In the study, presented here, we have ascertained two large Pakistani families (A and B) with autosomal recessive form of hypohidrotic ectodermal dysplasia and X-linked recessive isolated hypodontia. Genetic mapping showed linkage of family A to EDAR gene on chromosome 2q11-q13 and family B to EDA gene on chromosome Xq12-q13.1. Subsequently, DNA sequencing of the coding regions of EDAR and EDA genes revealed previously described mutations. Sequence analysis identified a four base-pair splice-junction deletion mutation (c.718_721delAAAG) in EDAR gene in family A and a missense mutation (c.T1091C; p.M364T) in EDA gene in family B. Recurrence of mutations in EDAR and EDA genes in unrelated families is evocative of the dispersion of ancestral chromosome in different locality groups through common ancestors.     

Successful treatment with interleukin‐17A antagonists of generalized pustular psoriasis in patients without IL36RN mutations

Generalized pustular psoriasis (GPP) is a potentially life‐threatening disease that can be attributed to mutations in IL36RN in a subgroup of patients. In small trials, interleukin (IL)‐17A and IL‐17RA antagonists have been shown to be effective in patients with generalized pustular psoriasis in Japan. We identified seven patients who received the IL‐17A antagonists secukinumab (six cases) or ixekizumab (one case) in two dermatological centers. All patients showed a good or excellent clinical response. Anti‐IL‐17A therapy was well tolerated and ongoing in all patients after an average therapy duration of 12.9 months. Analysis of IL36RN mutation status was performed in six patients, one patient carried a heterozygous mutation, while the other five patients did not show a mutation in IL36RN. This is the first report of a successful treatment of GPP patients without IL36RN mutations responding to anti‐IL‐17A therapy.     

Juvenile generalized pustular psoriasis with IL36RN mutation treated with short‐term infliximab

A 8‐year‐old Chinese boy with generalized pustular psoriasis (GPP) refractory to cyclosporine and methylprednisolone was treated successfully with two infusions of infliximab 3.3 mg/kg. He remained in remission for 21 months. Direct sequencing of IL36RN gene showed a homozygous mutation, c.115 + 6T>C. Juvenile GPP is a rare severe form of psoriasis occasionally associated with life‐threatening complications. Like acitretin, cyclosporine and methotrexate, infliximab has been reported to be effective for juvenile GPP in case reports. However, there is a lack of data in the optimal treatment course of infliximab for juvenile GPP. Prolonged administration of these medications may cause toxic or fatal complications. We suggest that short‐term infliximab regimen should be recommended as a choice for acute juvenile GPP refractory to traditional systemic therapies. WBC count and CRP are sensitive parameters to reflect the disease activity and evaluate the effectiveness of treatment. Monitoring CD4 T lymphocyte count, preventing and correcting CD4 lymphocytopenia are important in the treatment course of juvenile GPP.     

Variation of mutant allele frequency in <Emphasis Type="Italic">NRAS</Emphasis> Q61 mutated melanomas

Background

Somatic mutations of BRAF or NRAS activating the MAP kinase cell signaling pathway are present in 70% of cutaneous melanomas. The mutant allele frequency of BRAF V600E (M%BRAF) was recently shown to be highly heterogeneous in melanomas. The present study focuses on the NRAS Q61 mutant allele frequency (M%NRAS).

Methods

Retrospective quantitative analyze of 104 NRAS mutated melanomas was performed using pyrosequencing. Mechanisms of M%NRAS imbalance were studied by fluorescence in situ hybridization (FISH) and microsatellite analysis.

Results

M%NRAS was increased in 27.9% of cases. FISH revealed that chromosome 1 instability was the predominant mechanism of M%NRAS increase, with chromosome 1 polysomy observed in 28.6% of cases and intra-tumor cellular heterogeneity with copy number variations of chromosome 1/NRAS in 23.8%. Acquired copy-neutral loss of heterozygosity (LOH) was less frequent (19%). However, most samples with high M%NRAS had only one copy of NRAS locus surrounding regions suggesting a WT allele loss. Clinical characteristics and survival of patients with either <60% or ≥60% of M%NRAS were not different.

Conclusion

As recently shown for M%BRAF, M%NRAS is highly heterogeneous. The clinical impacts of high M%NRAS should be investigated in a larger series of patients.

     

<Emphasis Type="Italic">Cucumis sativus</Emphasis> fruit-potential antioxidant,anti-hyaluronidase,and anti-elastase agent

The aim of this study was to screen the antioxidant, anti-hyaluronidase, and anti-elastase activity of the lyophilized juice of Cucumis sativus fruit (CSLJ). The CSLJ was subjected to DPPH and superoxide radical scavenging assay in reference to butylated hydroxytoluene. The hyaluronidase and elastase inhibitory assay was performed in reference to oleanolic acid. Furthermore, the activities have been rationalized with HPLC analysis of the CSLJ with standard reference compound of ascorbic acid. The CSLJ exhibited DPPH-free radical and superoxide radical scavenging activity, IC₅₀ at a concentration of 14.73 ± 1.42 and 35.29 ± 1.30 μg/mL, respectively. The CSLJ also showed strong anti-hyaluronidase (^c P < 0.001) and anti-elastase (^c P < 0.001) activity, IC₅₀ at a concentration of 20.98 ± 1.78 and 6.14 ± 1.74 μg/mL, respectively. The HPLC ‘chromatogram’ of standard and CSLJ showed specific peak at retention time 2.905 and 3.066 min, respectively. Content of ascorbic acid was calculated with respect to the standard compound and it was found to be 3.5 ± 0.23% w/w. CSLJ is the rich source of ascorbic acid and this study thereby rationalizes the use of C. sativus as potential anti-wrinkle agent in cosmetic products.     

Antimelanogenic and antioxidative properties of <Emphasis Type="Italic">Bifidobacterium bifidum</Emphasis>

Various skin hyperpigmentation disorders consist in accumulation and overproduction of melanin. In this report, we investigated the melanogenesis inhibitory and antioxidant effects of Bifidobacterium bifidum culture filtrate. The results revealed that B. bifidum culture filtrate effectively suppresses murine tyrosinase activity and decreases the amount of intracellular melanin in a dose-dependent manner. Additionally, the bacterial culture filtrate-scavenged DPPH and ABTS radicals, and shows potent-reducing power in a dose-dependent pattern. Our results expand the application of B. bifidum culture filtrate in the development and research of skin-whitening ingredients.     

Searching for experimental models of <Emphasis Type="Italic">Pemphigus vulgaris</Emphasis>

The current knowledge on Pemphigus vulgaris (PV) pathophysiology suggests that blister formation relies on both PV IgG and non-IgG serum factors activity. PV autoimmunity seems to develop against both desmoglein 1/3 and acetylcholine receptors leading to transduction of signals to the cell mediated by phosphorilation events. Serum factors other than IgG also participate to PV acantholysis through apoptotic or cytokine-mediated mechanisms. Apart from the role played by each actor within the acantholysis, however, the current scenario arises important methodological issues. For example, the use of PV IgG or monoclonal anti-Dsg3 antibodies to experimentally reproduce the disease appears inadequate, as it does not take into account the role of non-IgG factors. On the basis of the above observations and those from our laboratories, here we propose that using whole sera from PV patients with active disease represents the most faithful manner to mimic the disease.     

Identification of mutations in the human <Emphasis Type="Italic">hairless</Emphasis> gene in two new families with congenital atrichia

Congenital atrichia (AUC) is a form of isolated alopecia with an autosomal recessive mode of inheritance. Patients are born with normal hair but this is shed almost completely during the first weeks or months of life and never regrows. In many families the development of papular lesions is noted as an additional phenotypic feature, which defines a related phenotype designated as atrichia with papular lesions (APL). Using positional cloning strategies and the molecular findings in hairless recessive (hr/hr) mice, an animal model for AUC, mutations in the human hairless gene (HR) have been identified as a cause of AUC and APL. To date, more than 20 different mutations of the HR gene have been reported in AUC and APL including different mutation types scattered over the entire HR gene length. In this report, we describe two families of Saudi Arabian and Jewish Iranian origin comprising a number of individuals with clinical features suggestive of AUC. We therefore hypothesized that affected members may carry mutations in the HR gene. After sequencing the complete coding region of the HR gene in the Saudi Arabian family, we identified a homozygous insertion of a G (c.2661dupG; p.Thr888DfsX38) in exon 12, resulting in a premature stop codon. In a Jewish Iranian patient, we identified a homozygous splice site mutation c.1557-1G > T in intron 4. The latter mutation has been previously reported in a compound heterozygous state. In the present report, we describe the second exonic insertion mutation in the human HR gene and the first mutation in exon 12. Our study emphasizes the importance of sequencing the complete coding sequence and exon/intron junctions in the molecular diagnostics of AUC and APL.