Daiki Rokunohe

Characterization of retinoic acid-inducible gene-I (RIG-I) expression corresponding to viral infection and UVB in human keratinocytes

BACKGROUND Retinoic acid-inducible gene-I (RIG-I) is a cytoplasmic protein that recognizes viral double-stranded RNA to induce the type I interferon (IFN) response. In human keratinocytes, RIG-I is induced by IFN-γ and tumor necrosis factor-α stimulation, and is abundantly expressed in psoriatic keratinocytes of the spinous and basal layers. OBJECTIVE This study investigated the effects of extraneous stimuli including viral infection and UVB exposure on RIG-I expression in human keratinocytes. METHODS Human skin keratinocytes (HaCaT cells) were stimulated by polyinosinic-polycytidylic acid (poly(I:C)), which mimics viral infection, and UVB exposure. We assessed the expression of RIG-I and IFN-regulatory factor (IRF)-1 in HaCaT cells by RT-PCR and Western blot analysis. Moreover, we investigated the effect of IRF-1 binding site of RIG-I gene promoter on the regulation of RIG-I expression by luciferase promoter assay and electrophoretic mobility shift assay. RESULTS Poly(I:C) induced RIG-I expression, while UVB inhibited basal RIG-I expression and the poly(I:C)-induced RIG-I overexpression in HaCaT cells. IRF-1, which binds to a regulatory element located on the RIG-I gene promoter, was required for both inductions of RIG-I expression. IRF-1 expression was enhanced three hours after the poly(I:C) stimulation, consistent with the RIG-I response to poly(I:C), and thereafter was suppressed. Moreover, UVB exposure promptly decreased IRF-1 expression, resulting in decreased IRF-1 protein binding to the RIG-I promoter, and consequently, decreased RIG-I expression. CONCLUSION Thus, suppression of RIG-I and IRF-1 expression caused by UVB exposure may partly explain the inhibition of skin-based immune responses, leading to viral infection and recrudescence.

Buschke–Ollendorff syndrome associated with hypertrophic scar formation: a possible role for LEMD3 mutation

mosome 6p22–24, which is not far away from PSORS1. Our study has some limitations. First, the identification of cases of schizophrenia and psoriasis relied on diagnostic codes in an administrative database. There remains a possibility of coding errors or misdiagnosis. Second, information about cigarette smoking, alcohol consumption and body mass index, which are associated with the risk of psoriasis, were not available in our dataset, leaving room for residual confounding. Third, as our data did not include complete information regarding medications taken, it is not possible for us to assess the confounding role of medications in the relationship between schizophrenia and psoriasis. In conclusion, our study suggests that there was a significant relationship between schizophrenia and psoriasis, particularly in women. Future molecular and genetic linkage studies are needed to elucidate the role of inflammatory processes in the pathomechanisms underlying the association between schizophrenia and psoriasis, as well as to explore the possibility of shared genetic aetiology.

Diffuse and focal palmoplantar keratoderma can be caused by a keratin 6c mutation

The palmoplantar keratodermas (PPKs) are a large group of genodermatoses comprising nearly 60 genetically distinct diseases. They are characterized by hyperkeratosis on the palms and soles with or without extrapalmoplantar hyperkeratotic lesions. Focal PPK is one of the hallmarks of pachyonychia congenita, a rare autosomal dominant disorder resulting from mutations in the keratin genes KRT6A, KRT6B, KRT16 or KRT17. Recently, in‐frame deletion mutations of KRT6C have been identified in three families with focal PPK with slight or no nail changes. We report here a novel KRT6C mutation identified in a Japanese family with PPK with phenotypic heterogeneity, presenting with not only focal but also diffuse hyperkeratosis. The proband had diffuse hyperkeratosis on the soles and small focal hyperkeratoses on the palms, while the two other affected individuals showed focal hyperkeratoses on the soles. All three patients were heterozygotes for c.1414G>A in KRT6C, predicted to result in p.Glu472Lys. These findings strongly suggest that screening of patients with nonepidermolytic diffuse PPK, in whom the pathogenic mutations are yet to be determined, might identify mutations in KRT6C.

Two Japanese familial cases of punctate palmoplantar keratoderma caused by a novel AAGAB mutation, c.191_194delCAAA

o Japanese familial cases of punctate lmoplantar keratoderma caused by a vel AAGAB mutation, c.191_194delCAAA the pressure-bearing areas of the plantar skin [1,2]. Recently, two consecutive studies identified that PPPK1 was caused by mutations in the AAGAB gene, encoding alphaand gamma-adaptin binding protein p34 (p34) [1,2]. Subsequently, several AAGAB mutations were reported in PPPK1 families from Europe, the Middle East, and Asia [1–8]. Here, we describe two Japanese PPPK1 pedigrees harboring the same, novel AAGAB mutation. This work was conducted in accordance with the Declaration of Helsinki ywords: lmoplantar keratoderma;

Calcineurin/NFAT-dependent regulation of 230-kDa bullous pemphigoid antigen (BPAG1) gene expression in normal human epidermal keratinocytes

BACKGROUND AND OBJECTIVE Cyclosporin A (CsA) is utilized widely for treatment of inflammatory skin diseases, such as psoriasis vulgaris. The therapeutic effects of CsA are thought to be mediated by its immunosuppressive action on infiltrating lymphocytes in the lesional skin. CsA also inhibits epidermal keratinocyte proliferation, suggesting a direct biological action on keratinocytes. Here we tested the hypothesis that CsA can modulate the expression of the nuclear factor of activated T-cell (NFAT) in epidermal keratinocytes. We also investigated whether the keratinocyte-specific gene expression is modified by CsA through NFAT activity in association with differentiation induction. METHODS RT-PCR was performed using total RNAs extracted from cultured normal human epidermal keratinocytes (NHEK), normal human dermal fibroblasts (NHDF), and normal human epidermal melanocytes (NHEM) for detecting NFAT isomolecules. Transient transfections of NHEK with a 230-kDa bullous pemphigoid antigen (BPAG1) promoter/luciferase reporter gene and the luciferase assay were conducted for examining the effect of CsA on the promoter activity of the BPAG1 gene. Electrophoretic gel mobility shift assays (EMSA) with probes containing NFAT consensus sequences for analyzing the binding activities of the nuclear proteins extracted from NHEK. RESULTS RT-PCR revealed expression of all of the five isoforms of NFAT in the cell lines examined. The mRNA expression levels of NFAT1, NFAT2, BPAG1, and involucrin were downregulated by CsA treatment in NHEK. The luciferase assay indicated suppression of the promoter activity by CsA. EMSA with NFAT consensus probes identified in the BPAG1 promoter region demonstrated specific binding activity in the nuclear proteins of epidermal keratinocytes. CONCLUSION As reported previously, our results indicate that epidermal keratinocytes possess calcineurin/NFAT system, which is suppressed by CsA. In addition, the data suggest that CsA can downregulate the BPAG1 gene expression perhaps via the NFAT consensus cis-elements in the BPAG1 promoter region. Such transcriptional regulatory system might be involved in the regulation of keratinocyte differentiation and proliferation.

Linear immunoglobulin A bullous dermatosis possibly induced by mefenamic acid

Dear Editor, Linear immunoglobulin A bullous dermatosis (LABD) is a relatively rare autoimmune blistering disease characterized clinically by the presence of small tense blisters and immunologically by the presence of immunoglobulin (Ig)A at the dermal–epidermal junction. Idiopathic, systemic disease-related and drugrelated types of this disorder have been described so far. We report the first case of LABD possibly associated with mefenamic acid, which is well known to induce commonly fixed drug eruptions. A 69-year-old Japanese woman presented with multiple blisters and erosions on her trunk, hip and thighs. She first noticed the skin eruption after taking mefenamic acid for 7 days for treatment of a common cold and the skin lesions were only a few blisters at the beginning. She visited a dermatology practitioner and a diagnosis of fixed drug eruption by mefenamic acids was made. Thus, she was given an oral antihistaminic drug and topical corticosteroid ointment. However, the eruption exacerbated and she was then referred to our clinic. Physical examination revealed some tense bullae and edematous erythema with vesiculobullae and erosions arranged annularly on her trunk, hip, thighs and upper extremities (Fig 1a,b). Mucosal lesions were not found in mucous membranes and there were no scars and milia. History taking revealed that the patient had experienced a similar eruption after taking mefenamic acids approximately 7 years before visiting us. Histological examination showed a subepidermal blister with a dense inflammatory infiltrate of lymphocytes, neutrophils and eosinophils in the edematous superficial dermis. Acantholysis and papillary abscess were not seen. All the laboratory data obtained were within normal limits. Direct immunofluorescent study revealed linear deposits of IgA and IgG at the basement membrane

Novel and recurrent nonsense mutation of the SLC39A4 gene in Japanese patients with acrodermatitis enteropathica

Acrodermatitis enteropathica (AE, OMIM 201100) is a rare autosomal recessive disease characterized by hypozincaemia derived from the inability to absorb intestinal zinc. The clinical manifestations of AE include growth retardation, diarrhoea, alopecia, repeated infections due to immune dysfunction, and characteristic skin lesions on acral and periorificial areas. The hypozincaemia in AE is believed to be caused by a defect in a zinc transporting protein. Recently, the gene encoding this zinc transporting protein was identified on chromosomal region 8q24.3, and subsequently SLC39A4 located on the chromosome was identified as the AE gene. SLC39A4 encodes the ZIP4 zinc transporter, which transports zinc into the cytoplasm, mainly in the intestine. Here, we report two Japanese families with AE, in which a novel nonsense mutation in the SCL39A4 gene was identified.

Rubinstein-Taybi syndrome with multiple pilomatricomas: The first case diagnosed by CREBBP mutation analysis

Rubinstein-Taybi syndrome (RTS, OMIM #180849, #613684) is a rare genetic disorder characterized by mental retardation and multiple congenital anomalies. Although approximately 60% of cases are reportedly associated with mutations in the CREBBP gene [1] or the EP300 gene [2], the etiology of RTS is heterogeneous and remains to be elucidated. The cAMP-response element-binding protein-binding protein (CREBBP) encoded by CREBBP has a histone acetyl/lysine-transferase (HAT or KAT) activity and function as a transcription co-activator, with more than 400 described interaction partners, regulating the expression of many genes during development and postnatal life [3]. RTS is associated with an increased risk for development of tumors such as lymphoma, leukemia and neural tumors [1]. RTS is also known to be accompanied with multiple pilomatricomas, however, only six cases have been reported to date [4–6]. Furthermore, characteristics of CREBBP mutations in these cases are unknown. A recent case report described a CREBBP mutation (c.6127C > T, p. Q2043X) in an RTS patient who developed a solitary pilomatricoma on the scalp [7]. However, the association between the development of pilomatricoma and CREBBP mutations needs to be discussed further. Pilomatricoma is a non-hereditary benign tumor which is considered to be derived from the hair matrix. Stabilizing mutations in b-catenin, which is encoded by CTNNB1, are known to be involved in the development of pilomatricomas [8]. Multiple pilomatricomas have been reported to be associated with other genetic disorders, Turner syndrome, Gardner syndrome, Sotos syndrome, and Kabuki syndrome; the most frequent association is with myotonic dystrophy. Herein, we present the first report of a CREBBP mutation in an RTS patient with multiple pilomatricomas. The proband is a 12-year-old girl, referred to our department for the evaluation and treatment of multiple congenital hard tumors. Consanguineous marriage was denied by the parents. She had two brothers and her family history was unremarkable. On physical examination, she had a short stature (139 cm) and obesity (45 kg). Clinical features included characteristic facial dysmorphia (higharched eyebrows and prominent nose with nasal septum extending below the alae nasi), broad thumbs and halluces (Fig. 1A), intellectual disability, and suspected optic nerve atrophy. The patient had seven stony-hard tumors on her neck (Fig. 1B), arms, and trunk. All tumors were surgically excised under general anesthesia. Histology revealed that all the resected tumors had basophilic cells and shadow cells with partial ossification (Fig. 1C); they were diagnosed as pilomatricomas. Based on these clinical features, the patient was diagnosed as RTS.

Novel p.M1T and recurrent p.G301S mutations in cathepsin C in a Japanese patient with Papillon-Lefèvre syndrome : Implications for understanding the genotype/phenotype relationship

[1] Benjamin CL, Ananthaswamy HN. P53 and the pathogenesis of skin cancer. Toxicol Appl Pharmacol 2007;224:242–8. [2] Perez MI, Robins P, Biria S, Roco J, Siegel E, Pellicer A. P53 oncoprotein expression and gene mutations in some keratoacanthomas. Arch Dermatol 1997;133: 189–93. [3] Borkowski A, Bennett WP, Jones RT, Borkowski P, Harris CC, Ferreira LR, et al. Quantitative image analysis of p53 protein accumulation in keratoacanthomas. Am J Dermatopathol 1995;17:335–8. [4] Putti TC, Teh M, Lee YS. Biological behavior of keratoacanthoma and squamous cell carcinoma: telomerase activity and COX-2 as potential markers. Mod Pathol 2004;17:468–75. [5] Burnworth B, Arendt S, Muffler S, Steinkraus V, Bröcker EB, Birek C, et al. The multi-step process of human skin carcinogenesis: a role for p53, cyclin D1, hTERT, p16, and TSP-1. Eur J Cell Biol 2007;86:763–80. [6] Ribeiro D, Narikawa S, Marques ME. Expression of apoptotic and cell proliferation regulatory proteins in keratoacanthomas and squamous cell carcinomas of the skin. Pathol Res Pract 2008;204:97–104. [7] Kerschmann RL, McCalmont TH, LeBoit PE. p53 oncoprotein expression and proliferation index in keratoacanthoma and squamous cell carcinoma. Arch Dermatol 1994;130:181–6. [8] Kubo Y, Urano Y, Yoshimoto K, Iwahana H, Fukuhara K, Arase S, et al. p53 gene mutations in human skin cancers and precancerous lesions: comparison with immunohistochemical analysis. J Invest Dermatol 1994;102:440–4.

Mycosis fungoides bullosa associated with bullous pemphigoid

recent primary infection, whereas the presence of a highavidity antibody indicates a past or recurrent infection. Moreover, during active infections, HHV-6 and HHV7 may cross-react. An IgM response to HHV-7 primary infection, therefore, may also be directed to HHV-6 with a reciprocal rising in antibody titer to both viruses. In neonates, maternal IgGs, which may persist to up to six months of age, interfere with the diagnosis of both HHV-6 and HHV-7 infections. Therefore, in the presence of symptoms compatible with primary HHV-6 infection during the first months, such as seizures accompanied by a cutaneous rash, the diagnosis may need, in addition to the detection of specific IgM, quantitative PCR testing. After primary infection, HHV-6 and HHV-7 remain latent in the body mostly in the salivary glands. Serologic assays cannot be sufficient to diagnose viral reactivations, and direct methods like PCR are preferred. Among the latter, however, the detection of the viral genome is not synonymous of active infection and only bona fide quantitative methods, which measure the HHV-6 and HHV-7 viral load in tissues, blood cells and, particularly, plasma and serum, are diagnostic, also permitting the follow-up of the active infection and suggesting a causal link. In addition, in diseases such as pityriasis rosea, which are most probably associated with the active replication of either or both HHV-6 and HHV-7, quantitative PCR assays may detect only one virus depending on the particular phase of the disease. In pityriasis rosea, HHV-7 behavior is unique. It replicates before HHV-6, but its replication tends to cease in the advanced phases. Another issue that involves quantitative methods is the possibility of chromosomal integration (ci) of HHV-6 that complicates the interpretation of a high viral load. In fact, subjects carrying ciHHV-6 present with high levels of HHV DNA in plasma, which, however, persist over time. In these cases, comparisons of the effects of viral loads on multiple fluids and tissues, together with methods that detect the expression of HHV-6 genes associated with a productive infection and measures of lytic antigens in blood cells, may help to distinguish an active infection from a ciHHV-6 state. Lastly, immunohistochemistry can detect viral antigens expressed only during a given moment in the virus replication cycle, thereby indicating the status of the infection.