Deep intronic founder mutations identified in the ERCC4/XPF gene are potential therapeutic targets for a high-frequency form of xeroderma pigmentosum

Xeroderma pigmentosum (XP) is a genodermatosis defined by cutaneous photosensitivity with an increased risk of skin tumors because of DNA repair deficiency. The worldwide prevalence of XP is ~1 to 4 in million, with higher incidence in some countries and regions including Japan (1 in 22,000) and North Africa due to founder mutations and a high degree of consanguinity. Among XP, the complementation group F (XP-F), is a rare form (1% of worldwide XP); however, this is underdiagnosed, because the ERCC4/XPF gene is essential for fetal development and most of previously reported ERCC4/XPF pathogenic variants are hypomorphs causing relatively mild phenotypes. From the largest Japanese XP cohort study, we report 17 XP-F cases bearing two pathogenic variants, both identified in deep intronic regions of the ERCC4/XPF gene. The first variant, located in intron 1, is a Japanese founder mutation, which additionally accounts for ~10% of the entire Japanese XP cases (MAF = 0.00196), causing an aberrant pre-mRNA splicing due to a miss-binding of U1snRNA. The second mutation located in intron eight induces an alternative polyadenylation. Both mutations cause a reduction of the ERCC4/XPF gene expression, resulting in XP clinical manifestations. Most cases developed early-onset skin cancers, indicating that these variants need critical attention. We further demonstrate that antisense oligonucleotides designed for the mutations can restore the XPF protein expression and DNA repair capacity in the patients' cells. Collectively, these pathogenic variants can be potential therapeutic targets for XP.

[EARLY CHILDHOOD-ONSET PORK-CAT SYNDROME DUE TO SENSITIZATION BY BOTH CATS AND DOGS -A CASE REPORT]

We present a case of early childhood-onset pork-cat syndrome possibly due to sensitization by both cats and dogs. A 6-year-old girl was referred to our hospital because of repetitive episodes of urticaria when she consumed pork meat. The patient lived with a dog and the ground floor of her house was a veterinary clinic run by her veterinarian parents. Blood tests demonstrated high specific IgE (≥50UA/ml) against cat dander, dog dander, pork, Sus s 1, Fel d 2, Can f 1, Can f 2, and Can f 3. The skin prick test was positive for raw pork and beef. Western blotting analysis detected hot spots on 67-kDa proteins in pork meat and cat dander extract. Cross-reactivity between these two proteins was confirmed by an inhibition test. Furthermore, crossreactivity between pork meat and dog dander extract was also noted. Taken together, the diagnosis of porkcat syndrome was made, and both cats and dogs were suggested to have led to the sensitization. The patient was advised to only eat well-cooked pork, and has been followed thereafter without additional reactions. The previously reported cases of this syndrome developed during adolescence and young adulthood because a considerable period from the sensitization to the development cross-reactivity with pork meat is required. To our best knowledge, this is the youngest reported case of pork-cat syndrome among English and Japanese literatures. The nomenclature of this syndrome as pet animal-meat syndrome improves the understanding of the underlying pathogenesis of cross-reactivity between animal albumins and meat albumins.

4-(4-Hydroxyphenyl)-2-butanol (rhododendrol)-induced melanocyte cytotoxicity is enhanced by UVB exposure through generation of oxidative stress

4-(4-Hydroxyphenyl)-2-butanol (rhododendrol, RD), a skin-whitening agent, was reported to cause skin depigmentation in some users, which is attributed to its cytotoxicity to melanocyte. It was reported that cytotoxicity to melanocyte is possibly mediated by oxidative stress in a tyrosinase activity-dependent manner. We examined the effect of UV radiation (UVR) on RD-induced melanocyte cytotoxicity as an additional aggravating factor. UVR enhanced RD-induced cytotoxicity in normal human epidermal melanocytes (NHEMs) via the induction of endoplasmic reticulum (ER) stress. Increased generation of intracellular reactive oxygen species (ROS) was detected. Pretreatment with N-acetyl cysteine (NAC), antioxidant and precursor of glutathione significantly attenuated ER stress-induced cytotoxicity in NHEMs treated with RD and UVR. Increase in cysteinyl-RD-catechol and RD-pheomelanin in NHEMs treated with RD and UVR suggested that, after UVR excitation, RD or RD metabolites are potent ROS-generating substances and that the tendency to produce RD-pheomelanin during melanogenesis amplifies ROS generation in melanocytes. Our results help to elucidate the development mechanisms of RD-induced leukoderma and provide information for innovation of safe skin-whitening compounds.

Induced pluripotent stem cell-derived melanocyte precursor cells undergoing differentiation into melanocytes

Induced pluripotent stem cell (iPSC) technology offers a novel approach for conversion of human primary fibroblasts into melanocytes. During attempts to explore various protocols for differentiation of iPSCs into melanocytes, we found a distinct and self-renewing cell lineage that could differentiate into melanocytes, named as melanocyte precursor cells (MPCs). The MPCs exhibited a morphology distinctive from that of melanocytes, in lacking either the melanosomal structure or the melanocyte-specific marker genes MITF, TYR, and SOX10. In addition, gene expression studies in the MPCs showed high-level expression of WNT5A, ROR2, which are non-canonical WNT pathway markers, and its related receptor TGFβR2. In contrast, MPC differentiation into melanocytes was achieved by activating the canonical WNT pathway using the GSK3β inhibitor. Our data demonstrated the distinct characteristic of MPCs' ability to differentiate into melanocytes, and the underlying mechanism of interfacing between canonical WNT signaling pathway and non-canonical WNT signaling pathway.

Characteristics of Xeroderma Pigmentosum in Japan: Lessons From Two Clinical Surveys and Measures for Patient Care

Xeroderma pigmentosum (XP) is a rare autosomal recessive hereditary disease caused by deficiency in repair of DNA lesions generated by ultraviolet radiation and other compounds. Patients with XP display pigmentary change and numerous skin cancers in sun-exposed sites, and some patients show exaggerated severe sunburns even upon minimum sun exposure as well as neurological symptoms. We conducted a nationwide survey for XP since 1980. In Japan, the frequency of the XP complementation group A is the highest, followed by the variant type; while in the Western countries, those of groups C or D are the highest. Regarding skin cancers in XP, basal cell carcinoma was the most frequent cancer that afflicted patients with XP, followed by squamous cell carcinoma, and malignant melanoma. The frequency of these skin cancers in patients with XP has decreased in these 20 years, and the age of onset of developing skin cancers is higher than those previously observed, owing to early diagnosis and education to patients and care takers on strict prevention from sunlight for patients with XP. On the other hand, the effective therapy for neurological XP has not been established yet, and this needs to be done urgently.

Four-dimensional, dynamic mosaicism is a hallmark of normal human skin that permits mapping of the organization and patterning of human epidermis during terminal differentiation

Recent findings of mosaicism (DNA sequence variation) challenge the dogma that each person has a stable genetic constitution. Copy number variations, point mutations and chromosome abnormalities in normal or diseased tissues have been described. We studied normal skin mosaicism of a single nucleotide polymorphism (SNP) [rs1426654, p.Thr111Ala] in SLC24A5, an ion transporter gene. This SNP is unusual in that more than 90% of people of European descent have homozygous germline A/A alleles, while more than 90% of East Asians and Blacks have homozygous germline G/G alleles. We found mosaicism in neonatal foreskins as well as in 69% of nearly 600 skin surface scraping samples from 114 donors of different ages. Strikingly, donors with germline (buccal or blood) A/A, A/G or G/G genotypes had all three sequences (A/A, A/G or G/G) in the skin surface scrapings. SNP sequence differences extended within the epidermis in the vertical dimension from basal cell layer to the stratum corneum at the surface, as well as across the two-dimensions of the skin surface. Furthermore, repeated scrapings in the same location revealed variation in the sequences in the same individuals over time, adding a fourth dimension to this variation. We then used this mosaicism to track the movement of epidermal cells during normal differentiation and characterize the patterning of epidermal cells during terminal differentiation. In this coordinated proliferation model of epidermal differentiation, the skin surface is alternatively populated by synchronous, cycling of waves of cells, with each group having a different DNA sequence. These groups of cells abruptly flatten into large sheets at the surface providing patches of uniform SNP sequence. This four-dimensional mosaicism is a normal, previously unrecognized form of dynamic mosaicism in human skin.

Low incidence of hepatitis B virus reactivation and subsequent hepatitis in patients with chronic hepatitis C receiving direct-acting antiviral therapy

To determine the clinical characteristics of hepatitis B virus (HBV) reactivation in patients undergoing interferon-free antihepatitis C virus (HCV) therapy, we examined HBV DNA in 25 HBV co-infected patients and 765 patients with resolved HBV infection during and after treatment with direct-acting antiviral agents (DAAs). Among those with HCV genotype 1, asunaprevir plus daclatasvir was administered to 160 patients, sofosbuvir (SOF) plus ledipasvir to 438 patients and paritaprevir plus ombitasvir and ritonavir to 25 patients. In total, 167 patients with genotype 2 were treated with SOF plus ribavirin. Three patients with an HBV DNA level ≥2000 IU/mL were treated with entecavir before anti-HCV therapy, without reactivation of HBV. In 3 of 22 (12%) HBV surface antigen (HBsAg)-positive patients with an HBV DNA level <2000 IU/mL, the viral load increased during treatment. However, hepatitis flare did not occur in these patients. There was no significant difference in clinical history between patients with and without HBV reactivation. Among 765 patients with resolved HBV infection, HBV reactivation occurred in 1 (0.1%) patient after initial resolution, whose HBV DNA level spontaneously decreased after DAA therapy. We compared anti-HBs titres at baseline with those at post-DAA therapy in 123 patients without HBsAg. There was no significant difference in anti-HBs levels between the two points (P = .79). In conclusion, HBV reactivation was rare in HBsAg-negative patients treated with DAA therapy. Additionally, hepatitis did not occur in HBV-reactivated patients with a baseline HBV DNA level <2000 IU/mL before DAA therapy.

Factors Influencing Arteriovenous Fistula Dysfunction in Japanese Patients on Chronic Hemodialysis

Arteriovenous fistula dysfunction is a constant problem in chronic hemodialysis patients. We investigated the factors influencing fistula dysfunction in 184 patients on chronic hemodialysis. Stepwise regression analysis and Cox proportional hazards model were used to assess the relationship between fistula dysfunction and age, sex, duration of hemodialysis, diabetes mellitus, hematocrit, serum creatinine, blood urea nitrogen, KW, prothrombin time, blood pressure, anticoagulant therapy, dose of erythropoietin, calcium channel blocker therapy, and angiotensin-converting enzyme inhibitor therapy. Fistula dysfunction showed a significant relationship with a low systolic blood pressure, a low hematocrit, the presence of diabetes mellitus, and angiotensin-converting enzyme inhibitor therapy. These results suggested that treatment with angiotensin-converting enzyme inhibitors may help to prevent fistula dysfunction.

In Vitro and in Vivo Antigen-Induced Release of High-Molecular Weight Neutrophil Chemotactic Activity from Human Nasal Tissue

High molecular weight neutrophil chemotactic activity has been identified in resected human nasal polyps, inferior turbinates, and nasal secretions following antigen challenge. The estimated molecular weight, by gel filtration chromatography, was approximately 600,000. However, a heterogeneity of molecular weight in some patients was recognized. Our results suggest a possible role for high molecular weight-neutrophil chemotactic activity in the pathogenesis of hypersensitivity in the human nasal cavity.

Pharmacokinetics, efficacy and safety of daclatasvir plus asunaprevir in dialysis patients with chronic hepatitis C: pilot study

The aim of this study was to evaluate the pharmacokinetic profile of daclatasvir (DCV) and asunaprevir (ASV) dual therapy in haemodialysis patients infected with hepatitis C virus (HCV). Eighteen haemodialysis patients and 54 patients with normal renal function were treated with DCV and ASV dual therapy for 24 weeks. We evaluated the pharmacokinetic profiles of DCV and ASV and examined the rate of sustained virological response 12 weeks after the end of treatment (SVR₁₂ ) and incidence of adverse events during treatment of haemodialysis patients infected with chronic HCV genotype 1 infection. To adjust for potential differences in baseline characteristics between haemodialysis patients and patients with normal renal function, we used propensity scores case-control matching methods. Area under the plasma concentration time curve from 0 to 6 h (AUC_{0-6 h} ) of DCV was slightly lower in haemodialysis patients than in patients with normal renal function (P > 0.6). AUC_{0-6 h} of ASV was significantly lower in haemodialysis patients (P = 0.012). SVR₁₂ rates were 100% (18/18) for haemodialysis and 96.2% (52/54) for patients with normal renal function. Changes in mean log₁₀ HCV RNA levels and viral response were higher in haemodialysis patients compared to patients with normal renal function. No discontinuations due to adverse events occurred. In conclusion, DCV and ASV dual therapy for HCV infection is effective and safe with similar results in haemodialysis patients compared to patients with normal renal function.

The mechanisms of endothelin action in vascular smooth muscle cells

The mechanisms of actions were investigated in cultured rat aortic vascular smooth muscle A-10 cells. The A-10 cells have a single class of high affinity binding sites for ET with an apparent Mr of 65,000-75,000 on SDS-PAGE. Stimulation of cells with ET induces mobilization of Ca2+ from both intra- and extracellular pools to produce a biphasic increase in cytoplasmic free Ca2+ concentration. A dihydropyridine Ca2+ channel antagonist does not inhibit the second plateau phase of the [Ca2+]i increase which is dependent on extracellular Ca2+. ET stimulates phospholipase C to produce inositol trisphosphate and 1,2-diacylglycerol vai a pertussis toxin-insensitive G protein. These results indicate that the receptor activation by ET is coupled to phospholipase C activation and Ca2+ channel gating in vascular smooth muscle cells.

Heterogeneity in soil water and light environments and dispersal limitation: what facilitates tree species coexistence in a temperate forest?

In the present study, we analysed the habitat association of tree species in an old-growth temperate forest across all life stages to test theories on the coexistence of tree species in forest communities. An inventory for trees was implemented at a 6-ha plot in Ogawa Forest Reserve for adults, juveniles, saplings and seedlings. Volumetric soil water content (SMC) and light levels were measured in 10-m grids. Relationships between the actual number of stems and environmental variables were determined for 35 major tree species, and the spatial correlations within and among species were analysed. The light level had no statistically significant effect on distribution of saplings and seedlings of any species. In contrast, most species had specific optimal values along the SMC gradient. The optimal values were almost identical in earlier life stages, but were more variable in later life stages among species. However, no effective niche partitioning among the species was apparent even at the adult stage. Furthermore, results of spatial analyses suggest that dispersal limitation was not sufficient to mitigate competition between species. This might result from well-scattered seed distribution via wind and bird dispersal, as well as conspecific density-dependent mortality of seeds and seedlings. Thus, both niche partitioning and dispersal limitation appeared less important for facilitating coexistence of species within this forest than expected in tropical forests. The tree species assembly in this temperate forest might be controlled through a neutral process at the spatial scale tested in this study.

Thermochromic properties of Sn, W co-doped VO2 nanostructured thin film deposited by pulsed laser deposition

Tin (Sn) and tungsten (W) co-doped vanadium dioxide (VO2) nanostructured thin films with 50-nm thickness were deposited by pulsed laser deposition (PLD) to reduce the transition temperature and improve the IR transmittance. The crystal structure of the nanostructured thin films and the presence of elements were evaluated by XRD and XPS analysis. The transition temperature (T(c)) of 1 at% Sn-1 at% W co-doped VO2 nanostructured thin film was decreased to about 22 degrees C (from 70.3 to 48.5 degrees C) compared with the undoped VO2 nanostructured thin film. The transmittance width in the IR range of the co-doped nanostructured thin film decreased from 37.5% to 27% compared with the undoped VO2 nanostructured thin film. Also, the width of hysteresis was narrowed by Sn doping.

Factors associated with the presence of multiple Lugol-voiding lesions in patients with esophageal squamous-cell carcinoma

Multicentric squamous dysplasia of the esophagus is characterized by multiple Lugol-voiding lesions (LVLs) on Lugol chromoendoscopy. Multiple LVLs are associated with a very high risk of multiple cancers arising in the esophagus as well as the head and neck. To gain insight into the pathogenesis of multiple LVLs of the esophageal mucosa, we studied risk factors for the development of such lesions in 76 patients who had a current or previous diagnosis of esophageal squamous cell carcinoma. All patients underwent Lugol chromoendoscopy of the esophageal mucosa. The history of tobacco and alcohol use was documented. Polymorphisms of the aldehyde dehydrogenase type 2 (ALDH2) gene were identified by polymerase chain reaction using sequence-specific primers. Clinical factors related to multiple LVLs were analyzed. All patients with multiple LVLs were drinkers. On univariate analysis, male sex (odds ratio [OR] 15, 95% confidence interval [CI] 1.84-122.45: P = 0.011), presence of the ALDH2-2 allele (OR 4.5, 95% CI 1.55-13.24: P = 0.006), and smoking index ≥1000 (OR 2.6, 95% CI 1.02-6.6: P = 0.045) were associated with multiple LVLs. On multivariate analysis, male sex (OR 10.02, 95% CI 1.13-88.44: P = 0.038) and presence of the ALDH2-2 allele (OR 4.56, 95% CI 1.4-14.82: P = 0.012) were associated with multiple LVLs. Among drinkers, a daily alcohol intake of ≥100 g pure ethanol with the ALDH2-2 allele (OR 17.5, 95% CI 1.97-155.59: P = 0.01) and a daily alcohol intake of <100 g pure ethanol with the ALDH2-2 allele (OR 8.85, 95% CI 1.68-46.69: P = 0.01) more strongly correlated with multiple LVLs than did a daily alcohol intake of <100 g pure ethanol without the ALDH2-2 allele, whereas a daily alcohol intake of ≥100 g pure ethanol without the ALDH2-2 allele (OR 4.0, 95% CI 0.54-29.81: P = 0.18) did not. In conclusion, male sex and the ALDH2-2 allele are associated with an increased risk for multiple LVLs of the esophageal mucosa in patients with esophageal squamous cell carcinoma. Among drinkers with the ALDH2-2 allele, the risk of multiple LVLs increased in parallel to the daily alcohol intake.

Inhibition ofAchromobacterProtease I by Lysinal Derivatives

Z-Val-, Z-Pro-, Z-Leu-Leu-, and Z-Leu-Pro-lysinals and BZ-DL-lysinal were chemically synthesized and tested as novel inhibitors for Achromobacter protease I (API), a lysine-specific serine protease. Among the lysinal derivatives tested, Z-Val-lysinal was the most potent competitive inhibitor, its Ki being estimated as 6.5 nM in an esterolytic assay with Tos-Lys-OMe. In an amidolytic assay, Z-Leu-Leu-lysinal was the most potent inhibitor and the apparent mode of inhibition was non-competitive. The Kis of the other lysinal derivatives in both esterolytic and amidolytic assays were more than 10(3) times lower than that of leupeptin. Z-Val-lysinol, lacking the aldehyde group, was a poor competitive inhibitor. These results suggest that acyl-, acylaminoacyl-, and acylpeptidyllysinals function as a transition-state inhibitor for Achromobacter protease I.

Histopathologic findings in patients with idiopathic megacolon: a comparison between dilated and non-dilated loops

BACKGROUND

Idiopathic megacolon (IMC) is an intractable motility disorder in which chronic symptoms of colonic dysmotility appear with no mechanical cause. Although a pathological analysis is essential to understand the mechanism of IMC, no study has compared the histopathologic findings between dilated and non-dilated loops in IMC cases, and little is known about the proportion of each disease subtype.

METHODS

Fifty-three full-thickness samples (dilated loops, n = 31; non-dilated loops, n = 22) from 31 IMC cases and 16 samples (dilated loops; n = 8, non-dilated loops; n = 8) from eight controls were collected. All the samples were stained with hematoxylin-eosin (HE), Hu C/D antibody, and CD117 antibody to assess degenerative myopathy, degenerative neuropathy, inflammatory neuropathy, hypoganglionosis, and mesenchymopathy according to the London Classification. Findings of the dilated and non-dilated loop samples were compared, and the proportions of each subtype were analyzed.

KEY RESULTS

Based on a control study, <60 ganglion cells/cm was defined as hypoganglionosis in our series. Myopathy was observed in 11 patients (35.5%), neuropathy was in 19 patients (61.3%), and mesenchymopathy was in 10 patients (32.2%). An overlap between subtypes was observed in some cases. Surprisingly, the non-dilated loop samples exhibited very similar histopathologic abnormalities to those observed in the dilated loop samples in most cases.

CONCLUSIONS & INFERENCES

Our study is the first to compare the histopathologic findings between dilated and non-dilated loops in IMC patients. Histopathologic abnormalities precede the clinical manifestation of IMC, and may consequently lead to gradual colonic dilatation; however, detailed mechanism including dilation triggering factor needs further elucidation.

A novel triple secured technique for pancreatic reconstruction following pancreaticoduodenectomy for a soft pancreas

BACKGROUND/AIMS

Soft pancreases are susceptible to developing pancreatic fistula following pancreaticoduodenectomy. To reduce the incidence of pancreatic fistula after pancreaticoduodenectomy in patients with a soft pancreas, we developed a triple secured technique. In this study, we describe the details of this technique and also report on the postoperative outcomes.

METHODOLOGY

The triple secured technique employed an ultrasonic dissector for pancreatic transection with skeletonizing and ligating of the small pancreatic branch ducts, duct-invagination or duct-to-mucosa anastomosis for main pancreatic duct management, and, finally, four large stitches between the pancreatic stump parenchyma and the jejunal seromuscular layer to prevent minor pancreatic leakage. A total of 28 consecutive patients with a soft pancreas who underwent pancreaticoduodenectomy using our technique were included in this study.

RESULTS

Postopetrative complications occurred in 16 patients. Grade B pancreatic fistula developed in 6 patients. However, no grade C pancreatic fistula occurred in this series. Neither any reoperation nor in-hospital mortality was observed in this series.

CONCLUSIONS

Our triple secured technique after pancreaticoduodenectomy was feasible and safe, with an acceptable rate of grade B pancreatic fistula and no grade C pancreatic fistula for patients with a soft pancreas.

High frequency of PTEN mutations in nevi and melanomas from xeroderma pigmentosum patients

We examined nevi and melanomas in 10 xeroderma pigmentosum (XP) patients with defective DNA repair. The lesions had a lentiginous appearance with markedly increased numbers of melanocytes. Using laser capture microdissection, we performed DNA sequencing of 18 benign and atypical nevi and 75 melanomas (melanoma in situ and invasive melanomas). The nevi had a similar high frequency of PTEN mutations as melanomas [61% (11/18) versus 53% (39/73)]. Both had a very high proportion of UV-type mutations (occurring at adjacent pyrimidines) [91% (10/11) versus 92% (36/39)]. In contrast to melanomas in the general population, the frequency of BRAF mutations (11%, 7/61), NRAS mutations (21%, 13/62), and KIT mutations (21%, 6/28) in XP melanomas was lower than for PTEN. Phospho-S6 immunostaining indicated activation of the mTOR pathway in the atypical nevi and melanomas. Thus, the clinical and histological appearances and the molecular pathology of these UV-related XP nevi and melanomas were different from nevi and melanomas in the general population.