Regulation of Toll-like receptor-mediated inflammatory response by microRNA-152-3p-mediated demethylation of MyD88 in systemic lupus erythematosus

OBJECTIVE

microRNAs (miRNAs) play critical roles in embryogenesis, cell differentiation and the pathogenesis of several human diseases, including systemic lupus erythematosus (SLE). Toll-like receptors (TLRs) are also known to exert crucial functions in the immune response activation occurring in the pathogenesis of autoimmune diseases like SLE. Herein, the current study aimed to explore the potential role of miR-152-3p in TLR-mediated inflammatory response in SLE.

METHODS

We determined the miR-152-3p expression profiles in CD4+ T cells and peripheral blood mononuclear cells (PBMCs) harvested from patients with SLE and healthy controls, and analyzed the correlation between miR-152-3p expression and clinicopathological parameters. CD70 and CD40L expression patterns in CD4+ T cells were assessed by RT-qPCR and flow cytometry. ChIP was adopted to determine the enrichment of DNA methyltransferase 1 (DNMT1) in the promoter region of myeloid differentiation factor 88 (MyD88).

RESULTS

The obtained findings revealed that miR-152-3p was highly-expressed in CD4+ T cells and PBMCs of patients with SLE, and this high expression was associated with facial erythema, joint pain, double-stranded DNA, and IgG antibody. DNMT1 could be enriched in the MyD88 promoter, and miR-152-3p inhibited the methylation of MyD88 by targeting DNMT1. We also found that silencing miR-152-3p inhibited MyD88 expression not only to repress the autoreactivity of CD4+ T cells and but also to restrain their cellular inflammation, which were also validated in vivo.

CONCLUSION

Our study suggests that miR-152-3p promotes TLR-mediated inflammatory response in CD4+ T cells by regulating the DNMT1/MyD88 signaling pathway, which highlights novel anti-inflammatory target for SLE treatment.

Clinical and Biological Characterization of Skin Pigmentation Diversity and Its Consequences on UV Impact

Skin color diversity is the most variable and noticeable phenotypic trait in humans resulting from constitutive pigmentation variability. This paper will review the characterization of skin pigmentation diversity with a focus on the most recent data on the genetic basis of skin pigmentation, and the various methodologies for skin color assessment. Then, melanocyte activity and amount, type and distribution of melanins, which are the main drivers for skin pigmentation, are described. Paracrine regulators of melanocyte microenvironment are also discussed. Skin response to sun exposure is also highly dependent on color diversity. Thus, sensitivity to solar wavelengths is examined in terms of acute effects such as sunburn/erythema or induced-pigmentation but also long-term consequences such as skin cancers, photoageing and pigmentary disorders. More pronounced sun-sensitivity in lighter or darker skin types depending on the detrimental effects and involved wavelengths is reviewed.

Expression of Filaggrin and its Degradation Products in Human Skin Following Erythemal Doses of Ultraviolet B Irradiation

Epidermal filaggrin level is affected by ultraviolet B irradiation in animal and experimental models. This study examined the effect of ultraviolet B irradiation on epidermal filaggrin and natural moisturizing factors in vivo in healthy adults (n = 22). Participants were irradiated with 2 minimal erythema doses of ultraviolet B on the skin. Biopsies and tape strips were collected from skin irradiated 24 and 72 h earlier and from non-irradiated skin (control). Real-time quantitative PCR on skin biopsies showed significantly reduced profilaggrin mRNA expression 24 h after irradiation (mean relative mRNA expression ± standard deviation: control, 3.86 ± 2.06 vs. 24 h, 1.52 ± 0.640; p = 0.02; n = 8). Immunohistochemistry showed aberrant spatial distribution of filaggrin protein 72 h after irradiation (n = 3). High-pressure liquid chromatography of tape extracts showed no change in mean total natural moisturizing factor levels after irradiation, but mean trans-urocanic acid was significantly reduced, as expected (n = 8). In conclusion, erythemal doses of ultraviolet B exert acute effects on profilaggrin mRNA and filaggrin protein in human skin in vivo.

Duplicated Enhancer Region Increases Expression of CTSB and Segregates with Keratolytic Winter Erythema in South African and Norwegian Families

Keratolytic winter erythema (KWE) is a rare autosomal-dominant skin disorder characterized by recurrent episodes of palmoplantar erythema and epidermal peeling. KWE was previously mapped to 8p23.1-p22 (KWE critical region) in South African families. Using targeted resequencing of the KWE critical region in five South African families and SNP array and whole-genome sequencing in two Norwegian families, we identified two overlapping tandem duplications of 7.67 kb (South Africans) and 15.93 kb (Norwegians). The duplications segregated with the disease and were located upstream of CTSB, a gene encoding cathepsin B, a cysteine protease involved in keratinocyte homeostasis. Included in the 2.62 kb overlapping region of these duplications is an enhancer element that is active in epidermal keratinocytes. The activity of this enhancer correlated with CTSB expression in normal differentiating keratinocytes and other cell lines, but not with FDFT1 or NEIL2 expression. Gene expression (qPCR) analysis and immunohistochemistry of the palmar epidermis demonstrated significantly increased expression of CTSB, as well as stronger staining of cathepsin B in the stratum granulosum of affected individuals than in that of control individuals. Analysis of higher-order chromatin structure data and RNA polymerase II ChIA-PET data from MCF-7 cells did not suggest remote effects of the enhancer. In conclusion, KWE in South African and Norwegian families is caused by tandem duplications in a non-coding genomic region containing an active enhancer element for CTSB, resulting in upregulation of this gene in affected individuals.

T-lymphocytes are directly involved in the clinical expression of migratory circinate erythema in epidermolysis bullosa simplex patients

Epidermolysis bullosa simplex with migratory circinate erythema (EBS-MCE) is a rare EBS subtype characterised by migratory blistering lesions that resolve with brownish pigmentation. It is caused by a recurrent readthrough mutation, c.1649delG, in the tail of keratin 5. Here, we report a child with EBS-MCE and investigated the immunologic mechanisms underlying the migratory lesions in this patient. A skin biopsy from the patient from an active border of an erythematous lesion was used for the immunohistochemical characterisation of the inflammatory infiltrate and for TUNEL assay to detect apoptotic cells. We found abundant CD4+ and CD8+ T lymphocytes infiltrating the papillary dermis and lining the dermal-epidermal junction. A number of these cells expressed the activation marker CD69. CD83+ dendritic cells were present both in the epidermis and papillary dermis. Finally, TUNEL staining showed apoptosis of basal and suprabasal keratinocytes. These findings suggest a critical role of the cellular immunity in determining the EBS-MCE phenotype.

[Effect of proteflazid on TLRs expression by mononuclear leukocytes of peripheral blood and epithelial cells of mucous membranes and skin in patients with herpes-associated erythema multiforme and erythema annulare centrifugum]

The article reports survey data on 23 patients with erythemas, including 19 patients with herpes-associated erythema multiforme (HAEM) and 4 patients with Darier's erythema annulare centrifugum (DEAC). Patients in the initial state (baseline) and after two weeks of therapy with proteflazid were characterized by measuring the levels of Toll-like receptor (TLR) expression in peripheral blood mononuclear cells (PBMC) and in epithelial cells of the throat and the skin. The TLR expression in PBMC and skin was assessed by flow cytometry with monoclonal antibodies (ICA) (Caltag Laboratories, USA; Hycult Biotech, Netherlands) against relevant antigens. In addition, patients were also characterized by the content of subpopulations of lymphocytes expressing surface markers CD3, CD4, CD8, CD16, CD21, CD23, CD72, CD25, and HLA-DR in the peripheral blood, which was measured by flow cytometry. The therapy with proteflazid in patients with both HAEM and DEAC led to normalization of the level of both T-cell and B-cell immunity, which was manifested by an increase in the total number of lymphocytes, CD3+, CD4+, CD21+, and CD72+. Measurements of the dynamics of TLR expression in the course of immunotherapy showed an increase in the number of TLR 2, 3, 4, 7, 8, and 9 in PBMC (which was especially pronounced for TLR2) and in epithelium of the pharyngeal mucosa and skin (increased expression of TLR3, 7, and 9).

Local gene expression changes after UV-irradiation of human skin

UV-irradiation is a well-known translational pain model inducing local inflammation and primary hyperalgesia. The mediators and receptor proteins specifically contributing to mechanical or heat hyperalgesia are still unclear. Therefore, we irradiated buttock skin of humans (n = 16) with 5-fold MED of UV-C and assessed the time course of hyperalgesia and axon reflex erythema. In parallel, we took skin biopsies at 3, 6 and 24 h after UVC irradiation and assessed gene expression levels (RT-PCR ) of neurotrophins (e.g. NGF, BDNF, GDNF), ion channels (e.g. NaV1.7, TRPV1), inflammatory mediators (e.g. CCL-2, CCL-3) and enzymes (e.g. PGES, COX2). Hyperalgesia to mechanical impact (12 m/s) and heat (48°C) stimuli was significant at 6 h (p<0.05 and p<0.01) and 24 h (p<0.005 and p<0.01) after irradiation. Axon reflex erythema upon mechanical and thermal stimuli was significantly increased 3 h after irradiation and particularly strong at 6 h. A significant modulation of 9 genes was found post UV-C irradiation, including NGF (3, 6, 24 h), TrkA (6, 24 h), artemin, bradykinin-1 receptor, COX-2, CCL-2 and CCL-3 (3 and 6 h each). A significant down-regulation was observed for TRPV1 and iNOS (6, 24 h). Individual one-to-one correlation analysis of hyperalgesia and gene expression revealed that changes of Nav1.7 (SCN9A) mRNA levels at 6 and 24 h correlated to the intensity of mechanical hyperalgesia recorded at 24 h post UV-irradiation (Pearson r: 0.57, p<0.04 and r: 0.82, p<0.001). Expression of COX-2 and mPGES at 6 h correlated to the intensity of heat-induced erythema 24 h post UV (r: 0.57, p<0.05 for COX-2 and r: 0.83, p<0.001 for PGES). The individual correlation analyses of functional readouts (erythema and pain response) with local expression changes provided evidence for a potential role of Nav1.7 in mechanical hyperalgesia.

Localized reactive erythemas of different types in a family

"Reactive erythemas" is an umbrella term grouping several different conditions, all of which have in common the fact of being stereotypical inflammatory clinical patterns of the skin in response to disparate infectious, immune, or toxic factors. Typically, such eruptions are symmetrical or disseminated. The here reported cases are different. An elderly man underwent recurrent infections of an epidermoid cyst, accompanied by a typical erythema annulare centrifugum near the infectious focus. His grandson, aged ten months, presented with an infectious conjunctivitis, during the resolution of which two small annular lesions, compatible with annular erythema of infancy, appeared on the face. A man aged 42, respectively son and father of the two former patients, presented with an erythema multiforme target lesion proximally to an infected wound. There were no detectable predisposing factors in all cases. Familial cases of reactive erythemas have been reported. However, such limited distributions have not yet been described.

Typical and severe tumor necrosis factor receptor-associated periodic syndrome in the absence of mutations in the TNFRSF1A gene: a case series

Tumor necrosis factor receptor-1-associated periodic syndrome (TRAPS) is the most common autosomal dominant autoinflammatory disorder and is caused by mutations in the TNFRSF1A gene encoding the 55-kDa receptor for tumor necrosis factor (TNF)-α. TRAPS is characterized by recurrent attacks of fever, typically lasting from 1 to 3 weeks. In addition to fever, common clinical features include periorbital edema, a migratory erythematous plaque simulating erysipela with underlying myalgia, and arthralgia or arthritis. Serosal membrane inflammation is also a common feature, usually in the form of polyserositis. To date, at least 40 different TNFRSF1A mutations have been identified, but few patients with symptoms highly suggestive of TRAPS with no mutations in the TNFRSF1A gene have recently been described, thus suggesting that not all mutations are yet known or that alternative mechanisms might be involved in the pathogenesis of the disease. We report on three such patients here.

CINCA Syndrome

CINCA syndrome is a genetic disorder characterized by early onset of recurrent fever, rash, progressive articular and neurological involvement. We report a 7-year-old girl with CINCA syndrome with an infrequent manifestation of retinal vasculitis and a relative paucity of neurological signs. She had a de novo F309S mutation in exon 3 of CIAS1 gene on chromosome 1. This is the first report of this entity from India.

Clinical features of Blau syndrome and early-onset sarcoidosis and associating CARD15/NOD2 gene mutations

Sarcoidosis is a systemic inflammatory disease clinically characterized by swelling of bilateral hilar lymph nodes and histologically defined by non-caseating epithelioid cell granulomas. Among child cases, a special subtype, called the early-onset sarcoidosis, is known to appear in children younger than 4 years of age and to be characterized by a distinct triad of skin, joint and eye disorders without pulmonary involvement. On the other hand, autosomal dominantly-transmitted disease with a characteristic features similar to those of early-onset sarcoidosis has been reported as Blau syndrome. By a linkage analysis, the responsible gene for Blau syndrome has been mapped close to the IBD (Inflammatory Bowel Disease) 1 locus. After CARD15 (NOD2), originally identified as the susceptibility gene for Crohn's disease, was also proved to be responsible for Blau syndrome, the same gene mutations have been found in sporadic early-onset sarcoidosis cases. Nod2 recognizes a signal from bacterial cell wall component in the cytoplasm of monocytic cells to activate NF-kappaB, and thus can work as an intracellular sensor of bacteria. While the loss-of-function mutations in its LRR domain are associated with Crohn's disease, Blau syndrome and early-onset sarcoidosis are autoinflammatory diseases that are caused by the gain-of-function mutations in its NOD domain.

Erythrokeratodermia variabilis - variant with circumscribed variable erythema and periorificial fixed Bazex Dupré erythema

Erythrokeratodermia represents a group of rare genetic diseases characterized through disorders of keratinization. Clinically, they are presenting themselves with erythematous and hyperkeratosic lesions that can be persistent or variable as to their aspect and localization. They were classified in erythrokeratodermia variabilis (EKV) and erythrokeratodermia symmetric progressive (EKSP). We are presenting the case of a 9-years-old child which presents from birth facial and perioral erythema; erythematous and hyperkeratosic lesions with circinate character, extremely variable, localized especially on the anterior thorax (on the chest and in the axillar and inguinal folds). The neonatal debut, the clinical and histological aspect are suggestive elements for the EKV. In addition, the child has a plan frontal angioma and a congenital horizontal nistagmus. We realized a review of a literature data being different clinical variants of presentation of EKV and the eventual possible associations. It is considered the fact that the clinical presentation in the presented case corresponds to the variant of EKV with variable circinate erythema described by Bazex and Dupré. The case is also particular through the association of a plan frontal angioma, particularly of a congenital horizontal nistagmus, associations that we could not find in the literature.

HLA-DR association with the genetic susceptibility to develop ashy dermatosis in Mexican Mestizo patients

BACKGROUND

Ashy dermatosis, also known as erythema dyschromicum perstans, is an acquired benign disease, characterized by blue-gray pigment patches with erythematous borders. The cause is still unclear, but probably has an immunologic basis.

OBJECTIVE

The aim of this study was to determine gene frequencies of the HLA-DR alleles in Mexican patients with ashy dermatosis and compare them with ethnically matched healthy control subjects to reveal the genetic susceptibility to develop ashy dermatosis.

METHODS

We included 23 consecutive patients with clinical and histopathologic confirmed diagnosis of erythema dyschromicum perstans. Patients and control subjects received a questionnaire to determine their ethnic origin and a peripheral blood sample was taken for DNA extraction. Finally, Genetic HLA-DRB1 was performed by polymerase chain reaction sequence-specific oligonucleotide reverse dot blot hybridization.

RESULTS

Of the 23 patients included in this study, 65% were women and 35% were men. We observed that the disease was located in the trunk in 17 patients (74%) and the upper limbs in 15 patients (65%). The most frequent allele was HLA-DR4 (65%) (pC < 1 x 10(-6), odds ratio = 6.0, 95% confidence interval = 2.8-12.7) whereas in control subjects it was 23%. The most frequent molecular subtype in both patients and healthy control subjects was DRB1( *)0407, being statistically significant after comparing the two groups (pC < 1 x 10(-6), odds ratio = 7.0, 95% confidence interval = 3.1-15.8).

LIMITATIONS

Since this is a disease strongly influenced by ethnicity, extrapolation to other ethnic groups is limited.

CONCLUSIONS

Many factors influence the ethiopathogenesis of erythema dyschromicum perstans, but it is strongly suggested to have an important genetic susceptibility conferred by genes located within the major histocompatibility complex region.

[Blau syndrome--a chronic granulomatous, genetic disease]

Blau syndrome is a rare hereditary granulomatous disease presenting in patients of young age with exanthema, granulomatous arthritis and uveitis. Genetic analysis has shown an autosomal dominant inheritance and a number of specific mutations on chromosome 16q in codon 334, of which the most predominant are R334W and R334Q. Blau syndrome exists in Caucasian, Asian and Afro-American families, and de novo mutations have been reported. The estimated minimum incidence in Denmark is 0.05 per 100,000 person-years. Blau syndrome has pathological, clinical and therapeutic features in common with sarcoidosis but rarely involves the lungs or other parenchymatous organs. Discrimination between Blau syndrome and early-onset sarcoidosis should rely on chromosome analysis.

Inter-strain variance in late phase of erythematous reaction or leg contracture after local irradiation among three strains of mice

AIM

To gain insights into inter-strain differences in radiosensitivity.

METHODS

Mice of inbred strains, A/J, C57BL/6J, and C3H/HeMs, were irradiated at graded doses ranging from 20 to 60 Gy. Skin reaction and leg contraction were observed for a period of 230 days and between 175 and 350 days, respectively. Gene expressions in leg skin tissue were quantified by quantitative RT-PCR assay at 1, 12 and 72 h after 30 Gy irradiation. Mice were locally irradiated by using a Cs-137 source.

RESULTS

The three strains showed various degrees of susceptibility to irradiation has evaluated by skin scores. Large inter-strain differences were also detected in the lengths of contraction. Expressions of several genes such as Per3 and Rad51ap1 displayed inter-strain differences.

CONCLUSIONS

The continuum model of tissue injury revealed that genetic factor, which varies among strains, is one of the causes of variances in severity of damage after irradiation.

Erythromelanosis follicularis faciei et colli associated with keratosis pilaris in two brothers

Erythromelanosis follicularis faciei et colli is characterized by well-demarcated erythema, hyperpigmentation, and follicular papules. Since the original description, it has seldom been reported in the literature. We present two adolescent brothers who had this disorder associated with keratosis pilaris on the shoulders and the extensor surfaces of the arms. Dermatologic examination found brown-red pigmentation, erythema, and follicular papules on both maxillary, preauricular regions, and the cheeks. The lesions of the older brother were more prominent. Histopathologic examination of skin biopsy specimens taken from both brothers revealed hyperpigmentation of the basal layer, follicular plugging, dermal vascular dilatation and congestion, and perivascular inflammatory infiltration. We suggest that the coexistence of these two conditions in brothers implies a genetic inheritance and a possible relationship between the disorders.

Erythrokeratodermas: A classification in a state of flux?

The term 'erythrokeratodermas' or 'erythrokeratodermias' has been applied to a group of inherited disorders characterized by well-demarcated erythematous lesions and hyperkeratotic plaques. Connexin mutations have been demonstrated to be responsible for most cases of erythrokeratoderma variabilis but there remain some cases without demonstrated connexin mutations, suggesting genetic heterogeneity. The position of progressive symmetric erythrokeratoderma has become rather unclear. Loricin mutations have been found in some cases that clinically resemble variant Vohwinkel syndrome and other cases have features that overlap with those of erythrokeratoderma variablis. Whether progressive symmetric erythrokeratoderma exists as a distinct entity is under question.

Hereditary mucoepithelial dysplasia: clinical, ultrastructural and genetic study of eight patients and literature review

BACKGROUND

Hereditary mucoepithelial dysplasia is a dominantly inherited disease, mainly characterized by chronic mucosal lesions associated with keratitis, non-scarring alopecia, keratosis pilaris and perineal intertrigo. Since the original report by Witkop, this condition has been considered to be a disorder of desmosome/gap junction formation, but there has been no ex vivo investigation of these components using genetic and immunolabelling techniques.

OBJECTIVES

To perform light and immunoelectron microscopic studies, and partial genetic analysis on five patients in a family and three sporadic cases and to point out similarities of this rare disorder with chronic mucocutaneous candidiasis and other follicular keratosis syndromes, i.e. ichthyosis follicularis-alopecia-photophobia (IFAP), keratitis-ichthyosis-deafness (KID) and Siemens syndromes.

METHODS

Biopsies from the involved oral mucosa and armpit skin of patient 1 were prepared for standard histopathology, electron microscopy and immunocytochemistry. Microsatellite genotyping was performed in three affected family members. Direct sequencing after polymerase chain reaction amplification of the entire coding region was performed.

RESULTS

A 14-year-old male had recurrent keratitis, widespread keratosis pilaris, perineal intertrigo, hypotrichosis and oral mucosal involvement. A similar phenotype was noted in four members of his family and in three sporadic cases. Histological examination of oral mucosa and skin samples showed a psoriasiform pattern, dyskeratotic features and cytoplasmic vacuoles. Expression of connexins (Cx), desmosomal, adherens junction and cytoskeleton proteins (Cx 26, 32 and 43, desmogleins 1 and 2, plakoglobin, desmoplakins I-II, plakophilin 1, beta-catenin, E-cadherin, keratins, beta-tubulin, vimentin and actin) was normal. Ultrastructural studies showed a reduced number of desmosomes. Dyskeratotic cells exhibited internalized gap junctions, long filamentous inclusions reactive with antikeratin antibodies, and bundles of perinuclear fibres resembling clear tonofilaments. Genetic analysis in the studied family excluded the desmosomal cadherins in chromosome 18q12 as candidate genes.

CONCLUSIONS

A diagnosis of hereditary mucoepithelial dysplasia should be strongly suggested by the triad of non-scarring alopecia, well-demarcated erythema of oral mucosa and psoriasiform perineal rash, after exclusion of the clinically related follicular keratosis syndromes. Defective expression of cytoskeleton elements and/or a modification of mechanisms regulating junction-cytoskeleton assembly may be primarily responsible for impaired epithelial cohesion.

Intracellular distribution, assembly and effect of disease-associated connexin 31 mutants in HeLa cells

Mutations in connexin 31 (Cx31) are associated with erythrokeratodermia variabilis (EKV), hearing impairment and peripheral neuropathy; however, the pathological mechanism of Cx31 mutants remains unknown. This study analyzed 11 disease-associated Cx31 variants and one non-disease-associated Cx31 variant and compared their intracellular distribution and assembly in HeLa cells and their effect on these cells. The fluorescent localization assay showed no gap junction plaque formation in the cells expressing the recessive EKV-associated mutant (L34P) and four hearing impairment-associated mutants (66delD, 141delI, R180X and E183K), significantly reduced plaque formation in the cells with five EKV-associated dominant mutants (G12R, G12D, R42P, C86S and F137L) and no obvious change in the cells with two other mutants (I141V and 652del12). Immunoblotting analysis showed that 12 mutated Cx31s, like WT-Cx31, are able to form the Triton X-100 insoluble complex; however, the quantity of Triton X-100 insoluble complex in the transfected HeLa cells varied among different Cx31 mutants. Additionally, the expression of five EKV-associated dominant mutants (G12R, G12D, R42P, C86S and F137L) caused cell death in HeLa cells. However, the five hearing impairment-associated mutants did not induce cell death. The above results suggest that disease-associated mutants gain deleterious functions differentially. In summary, disease-associated Cx31 mutants impair the formation of normal gap junctions at different levels, and the diseases associated with Cx31 mutations may result from the abnormal assembly, trafficking and metabolism of the Cx31 mutants.

A new, recurrent mutation of GJB3 (Cx31) in erythrokeratodermia variabilis

BACKGROUND

Erythrokeratodermia variabilis (EKV) is an autosomal dominant or recessive genodermatosis characterized by the coexistence of randomly occurring, transient, erythematous patches and hyperkeratosis of the skin. The disorder has been mapped to chromosome 1p35.1 but is genetically heterogeneous. EKV may be caused by pathogenic mutations in one of two neighbouring connexin genes, GJB3 and GJB4, encoding the gap junction proteins Cx31 and Cx30.3, respectively. Twelve distinct mutations identified to date cluster either at the cytoplasmic amino-terminus or in the four transmembrane domains.

OBJECTIVES

To report a large family with EKV and an unrelated sporadic case.

METHODS

DNA amplification and mutation analysis, followed by denaturing high-performance liquid chromatography to confirm the segregation of the mutations in the two families with EKV.

RESULTS

A novel, recurrent GJB3 mutation (625C-->T; L209F) was identified in the family with EKV and in the unrelated sporadic case.

CONCLUSIONS

This mutation is the first to affect a conserved residue in the cytoplasmic carboxy-terminus of any connexin gene with a cutaneous phenotype, emphasizing its structural and/or functional importance.

Immunohistochemical demonstration of connexin-related epithelization defects in a lamb caused by (erythro)keratodermia variabilis

The distribution of four important connexins (Cx 26, 30, 31, 43) in the skin of a neonatal lamb with (erythro)keratodermia (EKV) was demonstrated using immunohistochemistry, including a very sensitive visualization system. The reaction staining for Cx 26, 30 and 31 was negative to weak in all skin structures, and only Cx 43 displayed weak to moderate positive reactions, although not uniformly distributed throughout the important systems (e.g. epidermis, hair follicle sheaths). Thus, the study proves for the first time that connexin defects are associated with the development of EKV in domesticated mammals, as they are in humans.

Erythema marginatum and hereditary angioedema

OBJECTIVE

To search for anaphylatoxin activity in plasma during episodes of erythema marginatum, and to evaluate the histology of erythema marginatum by electron microscopy and immunohistologic techniques.

METHODS

Plasma samples were studied for C5a activity by granulocyte aggregation, and C3 conversion by immunoelectrophoresis. A skin biopsy of erythema marginatum was done, and the tissue stained with a rabbit antibody to bradykinin.

RESULTS

No plasma anaphylatoxin was found. Dense deposits of bradykinin were discovered in stromal tissue and lining endothelial cells.

CONCLUSIONS

Bradykinin may be important in the causality of the erythema marginatum associated with hereditary angioedema.

Vascular endothelial growth factor promotes sensitivity to ultraviolet B-induced cutaneous photodamage

Acute ultraviolet B (UVB) irradiation of the skin results in erythema, vasodilation, edema, and angiogenesis, which is associated with the expression of vascular endothelial growth factor (VEGF) by epidermal keratinocytes. It is unclear, however, whether VEGF is required for the damage or repair process that occurs in the skin on UVB exposure. We subjected transgenic mice that overexpress VEGF, and their wild-type littermates, to graded doses of acute UVB irradiation. The skin of VEGF-overexpressing mice was highly photosensitive and became erythematic when exposed to half the UVB dose required to induce erythema in wild-type mice. Erythema was associated with proliferating dermal endothelial cells, cutaneous edema, and inflammatory cell infiltration. When subjected to 10 weeks of low-level UVB irradiation, no major changes were observed in wild-type mice, whereas VEGF transgenic mice developed skin damage associated with degradation of the dermal matrix and enhanced vascularization. Systemic treatment with an anti-VEGF blocking antibody reduced the sensitivity of wild-type mice to acute UVB irradiation without inhibiting post-UVB repair. Our results reveal that VEGF promotes the cutaneous damage that occurs after UVB exposure and that the VEGF signaling pathway might serve as a novel target for the prevention of UVB-induced photodamage.

Association of a long-chain fatty acid-CoA ligase 4 gene polymorphism with depression and with enhanced niacin-induced dermal erythema

Hypotheses about relationships between changes in membrane lipids and mental illness have focused primarily on three long-chain polyunsaturated fatty acids: arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Membrane deficiencies of these fatty acids have been reported in schizophrenia (AA, EPA, and DHA) and in depression (EPA and DHA). Long-chain fatty acid-CoA ligase type 4 (FACL4; MIM 300157) is a key enzyme involved in the metabolism of AA, EPA, and DHA. FACL4 selectively esterifies these fatty acids with co-enzyme A, forming acyl-co-A, which can then be incorporated into membrane phospholipid. We used niacin-induced dermal erythema as one index of AA metabolism to identify a common C to T single nucleotide polymorphism (SNP) in the first intron of the FACL4 gene (Xq22.3), which is associated with enhanced dermal erythema in both schizophrenia and control subjects. Male subjects with the T0 genotype showed greater dermal erythema following topical application of methylnicotinate, suggesting that this polymorphism may be in linkage disequilibrium with a functional polymorphism of the FACL4 gene that modulates re-sequestration of agonist-released free AA. We also examined the allele frequency of this polymorphism in 555 European-Americans (EA), including 229 control subjects, 198 subjects with major depression, 58 with schizophrenia or schizoaffective disorder, and 70 with alcohol dependence without co-morbid psychiatric illness. We observed a significant excess of the T allele in subjects with major depression, as compared with controls (49% vs. 38%; P = 0.003) and a non-significant excess of the T allele in schizophrenia (44%; P = 0.29). The allele frequency for subjects with alcohol dependence did not differ from controls.

Palpable arciform migratory erythema in an HIV patient, a CD8+ pseudolymphoma

BACKGROUND

Palpable arciform migratory erythema (PAME) is characterized by large, elevated, reddish annular lesions localized on the upper trunk. As its infiltrate consists predominantly of dense infiltrates of CD4+ lymphocytes with polyclonal T-cell receptor (TCR) gene rearrangement, it has been grouped as a rare member of the T-cell pseudolymphomas.

METHODS

We performed histology, immunophenotyping, and TCR-gamma gene rearrangement studies in an human immunodeficiency virus (HIV)-positive patient, CDC stage IIIB, who showed a clinically typical PAME.

RESULTS

While TCR-gamma gene rearrangement studies showed a polyclonal infiltrate confirming a pseudolymphoma, 85% of skin-infiltrating lymphocytes were CD8+ T cells.

CONCLUSION

PAME may also occur in HIV-positive patients with CD4+ deficiency. Our case demonstrates that regular CD4 counts and immunocompetence are not necessary for its pathogenesis.

Erythrokeratoderma variabilis without connexin 31 or connexin 30.3 gene mutation: immunohistological, ultrastructural and genetic studies

Erythrokeratoderma variabilis, characterized by migrating erythema and fixed keratotic plaques, is a rare congenital disorder which has recently been connected with connexin (Cx)30.3 or Cx31 gene mutations. We present a 9-month-old Japanese girl who exhibited the typical clinical features of the disease, but carried no Cx30.3 or Cx31 gene mutations. Histopathologically, regular acanthosis with hyperkeratosis and hypergranulosis was observed in her lesional skin. Upregulation of involucrin and loricrin expression, and a weak expression of Cx26 was immunohistochemically observed in the upper spinous and granular layers. Electron microscopy revealed no abnormality in the keratin filaments, cornified cell envelope or gap junctions. Direct sequencing revealed no pathogenetic mutations in the Cx26, Cx30.3, Cx31 or Cx31.1 genes in this patient. The results indicate that erythrokeratoderma variabilis is pathologically heterogeneous, and that abnormalities in keratinization other than Cx30.3 and 31 gene mutations may underlie some forms of this disease.

Erythrokeratodermia variabilis

A 47-year-old woman presented with both transient, figurate, erythematous patches and fixed, hyperkeratotic plaques on the upper extremities. Her cutaneous disease began in childhood and affects numerous siblings and her daughter. Her clinical presentation, history, and histopathologic analysis were consistent with erythrokeratodermia variabilis, which is a genodermatosis linked to mutations in the gene encoding for the gap-junction protein, connexin 31.

Progressive and symmetric erythrokeratoderma

A case of progressive and symmetric erythrokeratoderma in a 9-year-old boy is presented. The evidence for loricrin as a candidate gene for this disorder as well as the clinical features of this disease are reviewed.

A usual frameshift and delayed termination codon mutation in keratin 5 causes a novel type of epidermolysis bullosa simplex with migratory circinate erythema

We report here two unrelated families in Japan and Korea having patients with a unique type of epidermolysis bullosa simplex and a novel mutation in the keratin gene KRT5, i.e., a frameshift and delayed stop codon inconsistent with any subtype described before. The patients showed migratory circinate erythema and multiple vesicles on the circular belt-like areas affected by erythema. Electron microscopy of skin biopsies showed a reduction in the number of keratin intermediate filaments in the basal cells without tonofilament clumping. We identified a novel heterozygous deletion mutation (1649delG of KRT5) in both cases. This deletion is predicted to produce a mutant keratin 5 protein with a frameshift of its terminal 41 amino acids and 35 amino acids longer than the wild-type keratin 5 protein due to a delayed termination codon. As the same abnormal elongated mutant KRT5 gene was found in the independent families, the predicted abnormal elongated keratin protein is likely to lead to an atypical clinical phenotype that has never been reported, possibly by interfering with the functional interaction between keratin and its associated proteins.

Time course of ultraviolet B-induced erythema in people with red hair harbouring homozygous melanocortin 1 receptor mutations

It has previously been reported that the time course of erythema may be delayed in those with sun-sensitive skin types and those with skin cancer. One molecular explanation for this putative phenotype would be that it is caused by mutations of the melanocortin 1 receptor (MC1R). In the present study of 20 persons, 10 of whom were MC1R homozygous, we measured erythema over a 21-day period in response to a range of ultraviolet B doses using methods that improved on previous studies. We could detect no consistent differences in ultraviolet radiation-induced erythema between the groups studied. The pharmacological mechanisms underpinning such prolonged inflammatory responses merit further investigation.

Reticular erythrokeratoderma: a new disorder of cornification

Heritable disorders of cornification form a large, clinically and genetically heterogeneous group. Recent advances in molecular genetics provide for the first time the opportunity to reliably classify some of these disorders based on their underlying etiology. Many rare phenotypes, however, still remain unclassified and do not fit into established classification schemes. We report here a 12-year-old girl who developed an ichthyosis vulgaris-like skin disorder 6 months after birth. Several years later, the clinical features had changed considerably. The patient had developed streaks of hyperkeratotic, slightly scaling skin with underlying erythema distributed in a reticulate, occasionally annular pattern on the trunk and extremities. The lesions were stable and had not changed significantly in size or distribution over the ensuing years. Histopathologic and ultrastructural findings were nonspecific and there was no evidence for metabolic disorders. The partial clinical overlap with erythrokeratodermia variabilis prompted us to screen several connexin genes but no pathogenic mutations were identified. We believe that this disorder belongs to the group of erythrokeratodermas and represents a novel, previously unrecognized entity.

Cytokine polymorphisms play a role in susceptibility to ultraviolet B-induced modulation of immune responses after hepatitis B vaccination

UVB exposure can alter immune responses in experimental animals and humans. In an earlier human volunteer study, we demonstrated that hepatitis B-specific humoral and cellular immunity after vaccination on average were not significantly affected by UVB exposure. However, it is known that individuals differ in their susceptibility to UVB-induced immunomodulation, and it was hypothesized that polymorphisms in specific cytokines may play a role in this susceptibility. In this respect, we previously demonstrated that immune responses after hepatitis B vaccination are influenced by the minor allelic variant of IL-1 beta in the general population. For all volunteers, single nucleotide polymorphisms were determined for the following UV response-related cytokines: IL-1 receptor antagonist (+2018), IL-1 alpha (+4845), IL-1 beta (+3953), TNF-alpha (-308), and TNF-alpha (-238). Exposure to UVB significantly suppressed Ab responses to hepatitis B in individuals with the minor variant for the IL-1 beta polymorphism. Increased minimal erythema dose values (just perceptible), which resulted in higher absolute UVB exposures, were observed in the same individuals. There were no associations observed between UVB-induced immunomodulation and the other cytokine polymorphisms examined. This study indicates that individual susceptibility to UVB radiation needs to be considered when studying the effects of UVB in humans.

Clinical and diagnostic value of genetic testing in 216 Israeli children with Familial Mediterranean fever

OBJECTIVE

Familial Mediterranean fever (FMF) is an autosomal recessive disease with diverse clinical presentation. The FMF gene (MEFV) has recently been cloned and 30 point mutations causing the disease have been identified. We appraised the value of mutation analysis as a diagnostic test for FMF in symptomatic pediatric patients, and explored the possible correlations between MEFV genotypes and the diverse phenotypic expression of the disease.

METHODS

Two hundred sixteen children who met the clinical criteria for FMF underwent molecular genetic studies to detect the 3 most common mutations in the Israeli FMF patient population (M694V, V726A, E148Q). The mutations found were related to clinical presentation and disease severity, using the Tel-Hashomer severity score.

RESULTS

Of the 216 children who fulfilled the diagnostic criteria for FMF, 82 (38.0%) had 2 of the tested mutations, 73 (33.8%) had only one mutation, and 61 (28.2%) had none of the mutations studied. The M694V was the most frequent mutation, detected in 174 of 432 MEFV alleles (40.0%). The V726A mutation was found in 39 alleles (9.0%) and the E148Q mutation in 25 (5.8%). The severity score correlated with the number of mutations. Children with no mutations presented at an older age compared to children with one or 2 mutations. Children homozygous for the M694V mutation presented at a younger age, had a higher severity score, and more commonly had arthritis.

CONCLUSION

Limited genetic molecular testing for MEFV mutations may explain some of the FMF clinical variability, but is diagnostically ineffective. The use of clinical criteria remains essential in establishing the diagnosis of FMF.

Expression of a connexin31 mutation causing erythrokeratodermia variabilis is lethal for HeLa cells

The autosomal dominant skin disorder erythrokeratodermia variabilis (EKV) has been linked to mutations in the human connexin31 (hCx31) gene, which is expressed in the epidermis. We characterized and compared a pathogenic mutation resulting in replacement of amino acid glycine 12 with arginine (G12R) with wild-type hCx31 protein. HeLa cells were transfected with wild-type and mutant hCx31 cDNA, respectively, using different-constitutive and inducible-vector systems. Independent of the expression vector, wild-type and mutant hCx31 were expressed at comparative levels and localized at the plasma membranes. Mutated channels (hCx31G12R) showed higher conductance in dye coupling studies than wild type channels. Furthermore, HeLa cells died within 5 days after constitutive expression of the mutant protein. Using an inducible expression system, we demonstrated a direct correlation between survival/life span of transfected HeLa cells and expression level of the mutant protein, indicating a gain-of-function mechanism due to a defective channel closure mechanism.

Erythrokeratodermia variabilis with erythema gyratum repens-like lesions

A large pedigree with erythrokeratodermia variabilis (EKV) and erythema gyratum repens-like lesions is described. Clinical, laboratory, and histologic findings of this family are presented. The differential diagnoses of the following dermatoses with an erythematous and a hyperkeratotic component are discussed: erythrokeratodermia variabilis (Mendes da Costa), progressive symmetric erythrokeratoderma (Gottron), loricrin keratoderma, erythrokeratoderma en cocardes (Degos), Netherton syndrome, keratitis-ichthyosis-deafness (KID) syndrome, erythrokeratolysis hiemalis (Oudtshoorn disease), and nonbullous congenital ichthyosiform erythroderma.

A mutation in GJB3 is associated with recessive erythrokeratodermia variabilis (EKV) and leads to defective trafficking of the connexin 31 protein

Erythrokeratodermia variabilis (EKV) is a skin disorder characterized by variable (transient) erythemas and fixed keratosis. The disorder maps to chromosome 1p34-35, a location that contains the GJB3 gene encoding the gap junction protein connexin 31. Until now, only heterozygote mutations in the form of dominant inheritance have been described in this gene associated with EKV. We report here a homozygote mutation in the connexin 31 gene, found in a family that shows recessive inheritance of the disorder, thus providing the first molecular support for a recessive variant of EKV. The entire GJB3 coding sequence was scanned for mutations by sequencing. We detected a T-->C transition at position 101 of the coding sequence, which replaces a leucine with a proline at residue 34 of the protein (L34P). Evolutionary analysis shows that this mutation is located at a highly conserved region of connexin in the first putative transmembrane helix (TMH). In transfected keratinocytes, L34P connexin 31 had a cytoplasmic distribution, suggesting that the mutant form of this protein will not form normal gap junctions between adjacent cells. The change of leucine to proline is likely to alter the structure of the first TMH of connexin by inducing a kink, thus influencing connexon structure and function.

Physical and transcriptional map of the critical region for keratolytic winter erythema (KWE) on chromosome 8p22-p23 between D8S550 and D8S1759

Keratolytic winter erythema is an autosomal dominant skin disorder characterised by erythema, hyperkeratosis, and peeling of the skin of the palms and soles, especially during winter. The keratolytic winter erythema locus has been mapped to human chromosome 8p22-p23. This chromosomal region has also been associated with frequent loss of heterozygosity in different types of cancer. To identify positional candidate genes for keratolytic winter erythema, a BAC contig located between the markers at D8S550 and D8S1695 was constructed and sequenced. It could be extended to D8S1759 by a partially sequenced BAC clone identified by database searches. In the 634 404 bp contig 13 new polymorphic microsatellite loci and 46 single nucleotide and insertion/deletion polymorphisms were identified. Twelve transcripts were identified between D8S550 and D8S1759 by exon trapping, cDNA selection, and sequence analyses. They were localised on the genomic sequence, their exon/intron structure was determined, and their expression analysed by RT-PCR. Only one of the transcripts corresponds to a known gene, encoding B-lymphocyte specific tyrosine kinase, BLK. A putative novel myotubularin-related protein gene (MTMR8), a potential human homologue of the mouse acyl-malonyl condensing enzyme gene (Amac1), and two transcripts showing similarities to the mouse L-threonine 3-dehydrogenase gene and the human SEC oncogene, respectively, were identified. The remaining seven transcripts did not show similarities to known genes. There were no potentially pathogenic mutations identified in any of these transcripts in keratolytic winter erythema patients.

Biological consequences of cyclobutane pyrimidine dimers

In the skin many molecules may absorb ultraviolet (UV) radiation upon exposure. In particular, cellular DNA strongly absorbs shorter wavelength solar UV radiation, resulting in various types of DNA damage. Among the DNA photoproducts produced the cyclobutane pyrimidine dimers (CPDs) are predominant. Although these lesions are efficiently repaired in the skin, this CPD formation results in various acute effects (erythema, inflammatory responses), transient effects (suppression of immune function), and chronic effects (mutation induction and skin cancer). The relationships between the presence of CPD in skin cells and the subsequent biological consequences are the subject of the present review.