Eiji Nakano

Inhibitory effects of dietary Spirulina platensis on UVB-induced skin inflammatory responses and carcinogenesis.

Reactive oxygen species produced in response to UVR are important in skin tumor development. We have previously reported that deficiency of the Ogg1 gene, encoding the repair enzyme for 8-oxo-7,8-dihydroguanine (8-oxoG), increases skin tumor incidence in mice upon repetitive UVB exposure and modulation of UVB-induced inflammatory response. Spirulina platensis is used as a human food supplement because it contains abundant nutritional and antioxidant components. Therefore, we investigated the inhibitory effects of S. platensis on UVB-induced skin tumor development in Ogg1 knockout-(KO) mice and the wild-type (WT) counterpart. Dietary S. platensis suppressed tumor induction and development in both genotypes compared with our previous data without S. platensis. Induction of erythema and ear swelling, one of the hallmarks of UVB-induced inflammatory responses, was suppressed in the skin of Ogg1-KO mice and albino hairless mice fed with dietary S. platensis. Compared with untreated mice, S. platensis-administered mice showed significantly reduced 8-oxoG formation in the skin after UVB exposure. Moreover, we found that S. platensis effectively downregulated the signal proteins p38 mitogen-activated protein kinase, stress-activated protein kinase/c-Jun N-terminal kinase, and extracellular signal-regulated kinase after UVB exposure especially in Ogg1-KO mice. Our results suggest that S. platensis exerts antitumor effects against UVB irradiation in the skin through its anti-inflammatory and antioxidant effects.

Hydrochlorothiazide Enhances UVA-Induced DNA Damage

The UVA is currently thought to be carcinogenic because, similar to UVB, it induces the formation of cyclobutane pyrimidine dimers (CPDs). Various drugs have been reported to cause photosensitive drug eruptions as an adverse effect. Although the precise mechanism of photosensitive drug eruption remains to be elucidated, it is generally accepted that free radicals and other reactive molecules generated via UV‐irradiated drugs play important roles in the pathogenesis of photosensitive drug eruptions. The waveband of concern for photo‐reactive drugs is UVA‐visible light, but some extend into the UVB region. We tested whether photosensitive drugs could enhance CPD formation after UVA exposure by using isolated DNA in the presence of several reported photosensitive drugs using high‐performance liquid chromatography. We found that the diuretic agent hydrochlorothiazide (HCT) significantly enhanced the production of TT dimers over a wide range of UVA. Furthermore, we investigated whether UVA plus HCT could enhance CPD production in xeroderma pigmentosum model mice defective in nucleotide excision repair. Immunofluorescence studies showed that CPD formation in the skin significantly increased after 365 nm narrow‐band UVA irradiation in the presence of HCT, compared with that in wild‐type mice. HCT could be used with caution because of its enhancement of UVA‐induced DNA damage.

Differences in Clinical Phenotype among Patients with XP Complementation Group D: 3D Structure and ATP-Docking of XPD In Silico

TO THE EDITOR Xeroderma pigmentosum (XP) is an autosomal recessive hereditary disease that is classified into seven genetic complementation groups, A through G, of nucleotide excision repair (NER)deficient types and one NER-proficient variant type (DiGiovanna and Kraemer, 2012). Patients with XP complementation group D (XPD) display photosensitivity, proneness to skin cancer and neurological symptoms, but the severity varies. In XPD from Western countries, the single amino-acid change R683W is found in 73% of the patients and most of them suffer from neurological symptoms (Takayama et al., 1995; Kobayashi et al., 1997; Taylor et al., 1997; Viprakasit et al., 2001; Kobayashi et al., 2002; Boyle et al., 2008; Emmert et al., 2009; Ueda et al., 2009). In contrast, Japanese patients display only skin manifestations without neurological symptoms (Kobayashi et al., 1997; Taylor et al., 1997; Kobayashi et al., 2002). XPD protein is an ATP-dependent 50-30 DNA helicase, which exerts unwinding of a damaged DNA strand to facilitate repair of the DNA. Although the human XPD protein remains refractory to crystallization, the crystal structure of XPD proteins from the archea has been solved (Fan et al., 2008; Liu et al., 2008). These structures revealed that XPD functions as a helicase with two helicase motifs separated by an ATP-binding cleft and two additional domains, a Fe–S cluster and an Arch domain. In this study, we present six cases of Japanese XPD without neurological abnormalities in four families. All patients showed severe photosensitivity since birth, and their skin in the sunexposed areas was hyperpigmented and covered with numerous pigmented maculae with color variations from light brown to dark brown. Four patients developed skin cancer, but none of them show neurological signs. XPD1KO and XPD4KO were assessed by a neurologist and an otorhinologist. Their clinical characteristics have been summarized in Table 1. To determine the ability to repair UV-induced DNA damage, a colonyformation assay after UV irradiation and UV-induced unscheduled DNA synthesis (UDS) was assessed (Materials and Methods are described in Supplementary data). The dose range giving 37% cell survival and UV-induced UDS in patients’ cells was much lower compared with that in the healthy subjects but was higher than that in XP-A cells (Table 1). Genetic complementation tests were carried out by means of a host-cell reactivation assay. Luciferase activity was increased specifically when XPD cDNA was cotransfected into each patient’s cells. Therefore, we concluded that all cases belonged to XPD. Direct sequence analysis was performed on each exon of the genomic DNA of Accepted article preview online 13 January 2014; published online 13 February 2014 Abbreviations: NER, nucleotide excision repair; UDS, unscheduled DNA synthesis; XP, xeroderma pigmentosum; XPD, xeroderma pigmentosum complementation group D E Nakano et al. Genotype–Phenotype and Protein Structure of XPD

Fluorescence detection of cellular nucleotide excision repair of damaged DNA

To maintain genetic integrity, ultraviolet light-induced photoproducts in DNA must be removed by the nucleotide excision repair (NER) pathway, which is initiated by damage recognition and dual incisions of the lesion-containing strand. We intended to detect the dual-incision step of cellular NER, by using a fluorescent probe. A 140-base pair linear duplex containing the (6–4) photoproduct and a fluorophore–quencher pair was prepared first. However, this type of DNA was found to be degraded rapidly by nucleases in cells. Next, a plasmid was used as a scaffold. In this case, the fluorophore and the quencher were attached to the same strand, and we expected that the dual-incision product containing them would be degraded in cells. At 3u2005h after transfection of HeLa cells with the plasmid-type probes, fluorescence emission was detected at the nuclei by fluorescence microscopy only when the probe contained the (6–4) photoproduct, and the results were confirmed by flow cytometry. Finally, XPA fibroblasts and the same cells expressing the XPA gene were transfected with the photoproduct-containing probe. Although the transfer of the probe into the cells was slow, fluorescence was detected depending on the NER ability of the cells.

CXCL1 Inhibition Regulates UVB-Induced Skin Inflammation and Tumorigenesis in Xpa-Deficient Mice

Xeroderma pigmentosum complementation group A is a hereditary disease characterized by early onset of skin cancers and freckle-like pigmented maculae in sun-exposed sites. Although the etiology of the predisposition to UVR-induced skin tumors in xeroderma pigmentosum complementation group A is well investigated as a repair deficiency in UVR-induced DNA damage, the mechanism of exaggerated sunburn in patients with xeroderma pigmentosum complementation group A and whether UVR-induced inflammation relates to a skin tumor-prone phenotype remains to be elucidated. Using gene profiling of xeroderma pigmentosum complementation group A model mice, Xpa-deficient mice, we found that expression of CXCL1 in the skin and blood of Xpa-deficient mice increased significantly after UVB exposure over even a limited area compared with that of wild-type mice. We administered CXCL1 neutralizing antibody or the antioxidant agent, N-acetylcysteine, to Xpa-deficient mice after UVB irradiation and found significant suppression of blood levels of CXCL1, ear swelling and erythema, the hallmarks of inflammation and neutrophil chemotaxis. Xpa-deficient mice treated with chronic UVB exposure plus administration of CXCL1 neutralizing antibody or N-acetylcysteine yielded many fewer skin tumors compared with the control group. This indicates that the UVB-induced strong inflammatory response of Xpa-deficient mice plays a role in skin tumor development, which could be suppressed by regulating chemokines such as CXCL1.

The present status of xeroderma pigmentosum in Japan and a tentative severity classification scale.

Xeroderma pigmentosum (XP) is a rare autosomal recessive hereditary disease. Patients with XP have severe hypersensitivity to sunlight, resulting in skin cancers, and some patients have neurological symptoms. In Japan, XP complementation group A (XP‐A) is the most common form, and it is associated with severe neurological symptoms. We performed a nationwide survey on XP to determine the present status of XP in Japan. The distribution of complementation groups in Japan was considerably different from that in other countries, but there was a higher frequency in group A and the variant type, which is similar to previous reports in Japan. Basal cell carcinoma was the most frequent skin cancer that patients with XP developed, followed by squamous cell carcinoma and malignant melanoma. The frequency of these skin cancers in patients with XP‐A has decreased, and these skin cancers have been occurring in much older people than those previously observed. Diagnosing XP in patients at younger ages seems to encourage patients and their parents to use sun protection, which helps prevent skin cancer. We also created a tentative scale for classifying the severity of XP, and we evaluated the neurological symptoms of XP‐A using this severity scale. Our classification correlated well with patients age, suggesting that it may be useful and feasible in clinical practice to assess the progression of symptoms of each patient with XP and evaluate the effects of treatment in the future.

A 10-year follow-up of a child with mild case of xeroderma pigmentosum complementation group D diagnosed by whole-genome sequencing

Most patients with xeroderma pigmentosum complementation group D (XP‐D) from Western countries suffer from neurological symptoms, whereas Japanese patients display only skin manifestations without neurological symptoms. We have previously suggested that these differences in clinical manifestations in XP‐D patients are attributed partly to a predominant mutation in ERCC2, and the allele frequency of S541R is highest in Japan.

Japanese case of xeroderma pigmentosum complementation group C with a novel mutation

Dear Editor, A 1-year-old boy was referred to Kobe University Hospital requesting a possible diagnosis of xeroderma pigmentosum (XP). He had had freckle-like pigmentation on his face since he was a baby. At 9 months, his mother took him to the hospital because the number of freckles had been increasing. Since then, sunlight had been he avoided, his parents applied sunscreen and he seldom spent time outdoors during the day. At presentation, he manifested many freckle-like pigmented maculae on his face and the back of his hands (Fig. 1a). He had never experienced exaggerated sunburn reactions such as blister formation or prolonged erythema upon minimum sun exposure. Skin cancer, mental retardation and neurological symptoms were not observed. His family did not have similar symptoms, and his parents were not consanguineous. A genetic complementation test was carried out by means of host-cell reactivation assay using fibroblasts derived from the patient. Luciferase activity was increased specifically when XPC cDNA was transfected into the patient’s cells, which suggested that the patient belonged to XP complementation group C (XP-C). Genome sequence analysis indicated that the patient harbored a compound heterozygous mutation of c.1024_1025insG and c.1950C>T, resulting in p.D342GfsX32 and p.R579X in XPC (Fig. 1b). Based on these findings, the patient was diagnosed as XP-C. We also confirmed the expression of XPC protein by western blot

A case of acute heart failure due to myocardial infiltration of mycosis fungoides

Mycosis fungoides (MF) has been reported to be the most common cutaneous lymphoma with a good prognosis and myocardial infiltration is clinically rare. We hereby report a case of rapidly progressing acute heart failure due to myocardial infiltration by MF. Perfusion cardiac magnetic resonance imaging (MRI) demonstrated a massive perfusion defect in the left ventricle (LV) where multiple nodular enhancement areas by delayed enhancement MRI could be documented in the postero-lateral wall of the LV, which resulted in a deterioration of the LV function and mitral regurgitation. Autopsy confirmed the myocardial infiltration by the MF, which corresponded with the MRI findings. <Learning objective: Symptomatic heart failure patients with myocardial infiltration by mycosis fungoides (MF) have a poor prognosis because they could not undergo chemotherapy for primary disease. Therefore, early diagnosis is important for improvement of prognosis. The routine assessment of the cardiac involvement by cardiac magnetic resonance imaging as well as transthoracic echocardiography should be performed for an early recognition of myocardial infiltration even in asymptomatic MF patients.>.

A case of xeroderma pigmentosum complementation group C with diverse clinical features

Xeroderma pigmentosum (XP) is an autosomal recessive disease characterized by sensitivity to sunlight and increased risk of skin cancers. XP is classified into seven nucleotide excision repair-deficient types (A-G) and a variant type1 . Differential diagnosis of XP from other genetic pigmentary disorders such as dyschromatosis symmetrica hereditaria (DSH) and dyschromatosis universalis hereditaria (DUH) should be considered, which is sometimes difficult without DNA repair tests or a genetic diagnosis2 . DSH and DUH are autosomal dominant diseases characterized by hypo-and hyperpigmented maculae. Recently, ABCB6 was identified as a responsible gene for DUH3 . This article is protected by copyright. All rights reserved.