The LSH/DDM1 Homolog MUS-30 Is Required for Genome Stability,but Not for DNA Methylation in Neurospora crassa

LSH/DDM1 enzymes are required for DNA methylation in higher eukaryotes and have poorly defined roles in genome maintenance in yeast, plants, and animals. The filamentous fungus Neurospora crassa is a tractable system that encodes a single LSH/DDM1 homolog (NCU06306). We report that the Neurospora LSH/DDM1 enzyme is encoded by mutagen sensitive-30 (mus-30), a locus identified in a genetic screen over 25 years ago. We show that MUS-30-deficient cells have normal DNA methylation, but are hypersensitive to DNA damaging agents. MUS-30 is a nuclear protein, consistent with its predicted role as a chromatin remodeling enzyme, and levels of MUS-30 are increased following DNA damage. MUS-30 co-purifies with Neurospora WDR76, a homolog of yeast Changed Mutation Rate-1 and mammalian WD40 repeat domain 76. Deletion of wdr76 rescued DNA damage-hypersensitivity of Δmus-30 strains, demonstrating that the MUS-30-WDR76 interaction is functionally important. DNA damage-sensitivity of Δmus-30 is partially suppressed by deletion of methyl adenine glycosylase-1, a component of the base excision repair machinery (BER); however, the rate of BER is not affected in Δmus-30 strains. We found that MUS-30-deficient cells are not defective for DSB repair, and we observed a negative genetic interaction between Δmus-30 and Δmei-3, the Neurospora RAD51 homolog required for homologous recombination. Together, our findings suggest that MUS-30, an LSH/DDM1 homolog, is required to prevent DNA damage arising from toxic base excision repair intermediates. Overall, our study provides important new information about the functions of the LSH/DDM1 family of enzymes.     

Association between Psoriasis Vulgaris and Coronary Heart Disease in a Hospital-Based Population in Japan

BackgroundPsoriasis vulgaris is a chronic inflammatory skin disease with an immune-genetic background. It has been reported as an independent risk factor for coronary heart disease (CHD) in the United States and Europe. The purpose of this study was to investigate the association between psoriasis and CHD in a hospital-based population in Japan.MethodsFor 113,065 in-hospital and clinic patients at our institution between January 1, 2011 and January 1, 2013, the diagnostic International Classification of Diseases (ICD)-10 codes for CHD, hypertension, dyslipidemia, diabetes, and psoriasis vulgaris were extracted using the medical accounting system and electronic medical record, and were analyzed.ResultsThe prevalence of CHD (n = 5,167, 4.5%), hypertension (n = 16,476, 14.5%), dyslipidemia (n = 9,236, 8.1%), diabetes mellitus (n = 11,555, 10.2%), and psoriasis vulgaris (n = 1,197, 1.1%) were identified. The prevalence of CHD in patients with hypertension, dyslipidemia, diabetes, and psoriasis vulgaris were 21.3%, 22.2%, 21.1%, and 9.0%, respectively. In 1,197 psoriasis patients, those with CHD were older, more likely to be male, and had more number of the diseases surveyed by ICD-10 codes. Multivariate analysis showed that psoriasis vulgaris was an independent associated factor for CHD (adjusted odds ratio [OR]: 1.27; 95% confidence interval [CI]: 1.01–1.58; p = 0.0404) along with hypertension (adjusted OR: 7.78; 95% CI: 7.25–8.36; p < 0.0001), dyslipidemia (adjusted OR: 2.35; 95% CI: 2.19–2.52; p < 0.0001), and diabetes (adjusted OR: 2.86; 95% CI: 2.67–3.06; p < 0.0001).ConclusionPsoriasis vulgaris was independently associated with CHD in a hospital-based population in Japan.     

Poroelastic analysis of interstitial fluid flow in a single lamellar trabecula subjected to cyclic loading

Trabecula, an anatomical unit of the cancellous bone, is a porous material that consists of a lamellar bone matrix and interstitial fluid in a lacuno-canalicular porosity. The flow of interstitial fluid caused by deformation of the bone matrix is believed to initiate a mechanical response in osteocytes for bone remodeling. In order to clarify the effect of the lamellar structure of the bone matrix—i.e., variations in material properties—on the fluid flow stimuli to osteocytes embedded in trabeculae, we investigated the mechanical behavior of an individual trabecula subjected to cyclic loading based on poroelasticity. We focused on variations in the trabecular permeability and developed an analytical solution containing both transient and steady-state responses for interstitial fluid pressure in a single trabecular model represented by a multilayered two-dimensional poroelastic slab. Based on the obtained solution, we calculated the pressure and seepage velocity of the interstitial fluid in lacuno-canalicular porosity, within the single trabecula, under various permeability distributions. Poroelastic analysis showed that a heterogeneous distribution of permeability produces remarkable variations in the fluid pressure and seepage velocity in the cross section of the individual trabecula, and suggests that fluid flow stimuli to osteocytes are mostly governed by the value of permeability in the neighborhood of the trabecular surfaces if there is no difference in the average permeability in a single trabecula.     

Visualization of biodistribution of Zn complex with antidiabetic activity using semiconductor Compton camera GREI

Various types of zinc (Zn) complexes have been developed as promising antidiabetic agents in recent years. However, the pharmacological action of Zn complex is not elucidated because the biodistribution of the complex in a living organism has not been studied. Nuclear medicine imaging is superior technology for the noninvasive analysis of the temporal distribution of drug candidates in living organisms. Gamma-ray emission imaging (GREI), which was developed by our laboratory as a novel molecular imaging modality, was adopted to visualize various γ-ray–emitting radionuclides that are not detected by conventional imaging techniques such as positron emission tomography and single-photon emission computed tomography. Therefore, we applied GREI to a biodistribution assay of Zn complexes. In the present study, ⁶⁵Zn was produced in the ^natCu(p,n) reaction in an azimuthal varying field cyclotron for the GREI experiment. The distribution was then noninvasively visualized using GREI after the intravenous administration of a ⁶⁵Zn-labeled di(1-oxy-2-pyridinethiolato)zinc [Zn(opt)₂], ZnCl₂, and di(l-histidinato)zinc. The GREI images were validated using conventional invasive assays. This novel study showed that GREI is a powerful tool for the biodistribution analysis of antidiabetic Zn complexes in a living organism. In addition, accumulation of ⁶⁵Zn in the cardiac blood pool was observed for [Zn(opt)₂], which exhibits potent antidiabetic activity. These results suggest that the slow elimination of Zn from the blood is correlated to the antidiabetic activity of [Zn(opt)₂].     

Osteoprotegerin Prevents Development of Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs), which commonly occur among elderly individuals, are accompanied by a risk of rupture and subsequent high mortality. Establishment of medical therapies for the prevention of AAAs requires further understanding of the molecular pathogenesis of this condition. This report details the possible involvement of Osteoprotegerin (OPG) in the prevention of AAAs through inhibition of Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In CaCl₂-induced AAA models, both internal and external diameters were significantly increased with destruction of elastic fibers in the media in Opg knockout (KO) mice, as compared to wild-type mice. Moreover, up-regulation of TRAIL expression was observed in the media by immunohistochemical analyses. Using a culture system, both the TRAIL-induced expression of matrix metalloproteinase-9 in smooth muscle cells (SMCs) and the chemoattractive effect of TRAIL on SMCs were inhibited by OPG. These data suggest that Opg may play a preventive role in the development of AAA through its antagonistic effect on Trail.     

Effect of Proteinuria and Glomerular Filtration Rate on Renal Outcome in Patients with Biopsy-Proven Benign Nephrosclerosis

Background

Reduced estimated glomerular filtration rate (eGFR) and proteinuria are risk factors for end-stage renal disease (ESRD), of which benign nephrosclerosis is a common cause. However, few biopsy-based studies have assessed these associations.

Methods

We performed retrospective cohort study of 182 Japanese patients who underwent renal biopsy from June 1985 through March 2014 and who were diagnosed with benign nephrosclerosis. Competing risk regression analyses were used to investigate the effect of eGFR and proteinuria levels at the time of renal biopsy on the risk for renal events (ESRD or a 50% decline in eGFR from baseline).

Results

During a median 5.8-year follow-up, 63 (34.6%) patients experienced renal events. The incidence of renal events increased with lower baseline eGFR and greater baseline proteinuria levels. After adjustment for baseline covariates, lower eGFR levels (subhazard ratios [SHRs], 1.30; 95% confidence interval [CI], 1.01–1.67, per 10 mL/min/1.73 m²) and higher proteinuria levels (SHR, 1.52; 95% CI, 1.23–1.87, per 1.0 g/day) at the time of renal biopsy were associated independently with higher risk for renal events. Lower levels of serum albumin (SHR, 2.07; 95% CI, 1.20–3.55 per 1.0 g/dL) were also associated with renal events. Patients with both eGFR <30 mL/min/1.73 m² and proteinuria ≥0.5 g/day had a 26.7-fold higher risk (95% CI, 3.97–179.4) of renal events than patients with both eGFR ≥60 mL/min/1.73 m² and proteinuria <0.5 g/day.

Conclusions

Reduced eGFR and increased proteinuria as well as lower serum albumin at the time of renal biopsy are independent risk factors for renal events among patients with biopsy-proven benign nephrosclerosis.     

Lung Transplantation for Lymphangioleiomyomatosis in Japan

Background

Lung transplantation has been established as the definitive treatment option for patients with advanced lymphangioleiomyomatosis (LAM). However, the prognosis after registration and the circumstances of lung transplantation with sirolimus therapy have never been reported.

Methods

In this national survey, we analyzed data from 98 LAM patients registered for lung transplantation in the Japan Organ Transplantation Network.

Results

Transplantation was performed in 57 patients as of March 2014. Survival rate was 86.7% at 1 year, 82.5% at 3 years, 73.7% at 5 years, and 73.7% at 10 years. Of the 98 patients, 21 had an inactive status and received sirolimus more frequently than those with an active history (67% vs. 5%, p<0.001). Nine of twelve patients who remained inactive as of March 2014 initiated sirolimus before or while on a waiting list, and remained on sirolimus thereafter. Although the statistical analysis showed no statistically significant difference, the survival rate after registration tended to be better for lung transplant recipients than for those who awaited transplantation (p = 0.053).

Conclusions

Lung transplantation is a satisfactory therapeutic option for advanced LAM, but the circumstances for pre-transplantation LAM patients are likely to alter with the use of sirolimus.     

Characteristics of Glucose Transport in Neuronal Cells and Astrocytes from Rat Brain in Primary Culture

Glucose transport systems in cultured neuronal cells and astrocytes of rats were characterized by measuring the uptake of 2-deoxy-D-[3H]glucose ([3H]2-DG) into the cells. Various sugars inhibited 2-DG uptake by neuronal cells and astrocytes similarly, a finding indicating that the substrate specificities of the transporters in the two types of cells were almost the same. However, the Km values for 2-DG of neuronal cells and astrocytes were 1.7 and 0.36 mM, respectively. The uptake of 2-DG was strongly inhibited by cytochalasin B. Nucleosides, such as adenosine, inosine, and uridine, inhibited 2-DG uptake competitively in both neuronal cells and astrocytes. The uptake by both types of cells were also inhibited by forskolin, but not by cyclic AMP, an observation suggesting that forskolin bound directly to the transporters to cause inhibition. Its inhibition was competitive in astrocytes and noncompetitive in neuronal cells. Astrocytes contained a glucose transporter with a subunit molecular weight of 45K, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis after photoaffinity labeling using [3H]cytochalasin B as a probe.     

A Method for the Rapid Growth in Culture of Gametophytes of Equisetum arvense with Antheridia

Rapid growth in culture of Equisetum arvense gametophytes wasobtained using Murashige-Skoog's medium plus 3% (w/v) sucroseand continuous illumination. In darkness, growth was reducedand chlorophyll synthesis markedly inhibited. Antheridia formedon the top margin of gametophytes in light and darkness butarchegonia were not observed in either case. ¹Present address: Interdisciplinary Research Institute of EnvironmentalSciences, Higashi-yanagi-cho, Nishi-iru, Shichihon-matsu, Itsutsuji-dori,Kamigyo-ku, Kyoto, 602 Japan. (Received June 5, 1989; Accepted September 12, 1989)