Association of vitamin D receptor gene polymorphism with renal cell carcinoma in Japanese

Molecular epidemiologic studies have reported a relationship between 1alpha,25 dihydroxyvitamin D3 (1,25(OH)2D3) and the development and progression of malignant tumors. (1,25(OH)2D3) exerts its biological activity by binding the vitamin D receptor (VDR), while recent studies have demonstrated that VDR gene polymorphisms affect serum levels of (1,25(OH)2D3). Serum levels of (1,25(OH)2D3) are reported to be significantly lower in patients with renal cell carcinoma (RCC) compared to non-cancer control patients. The purpose of this study was to investigate the TaqI VDR polymorphism in Japanese RCC patients and non-cancer controls in order to determine if an association exists between VDR genotype and the risk of developing RCC as well as clinical risk factors. A total of 102 RCC patients and 204 controls were genotyped for a previously described TaqI restriction fragment length polymorphism (RFLP) of the VDR gene. Products were digested into T allele or the t allele according to the absence or presence of a TaqI restriction site. Individuals were classified as TT, Tt or tt. The genotype TT was statistically more frequent among RCC patients (80.4%) compared to controls (61.8%) (OR = 2.54; 95% CI, 1.44-4.46; p = 0.0006). In addition, the occurrence of the genotype TT was significantly higher in patients with rapid-growth-type group (92.1%) compared to slow-growth-type group (73.4%) (OR = 4.22; 95% CI, 1.15-15.53; p = 0.0175). These data demonstrate that VDR genotype plays an important role in determining the risk of developing more aggressive RCC in Japanese.     

Establishment of Dental Epithelial Cell Line (HAT-7) and the Cell Differentiation Dependent on Notch Signaling Pathway

Rat incisors grow continuously throughout life. Producing a variety of dental epithelial cells is performed by stem cells located in the cervical loop of the incisor apex. To study the mechanisms for cell differentiation, we established a dental epithelial cell line (HAT-7) originating from a cervical loop epithelium of a rat incisor. Immunochemical studies showed that HAT-7 produced the cells expressing amelogenin, ameloblastin, or alkaline phosphatase (ALP). To illustrate a role of Notch signaling in the determinant of the cell fate, we examined expression patterns of Notch1 and Jagged1 in HAT-7 density dependently. At lower cell density, Notch1- or Jagged1-expressing cells were not seen. However, when they were fully confluent, cells began to express Notch1 or Jagged1 strongly. Some ALP-positive cells were almost consistent with Notch1-expressing cells but not Jagged1-expressing cells. These results suggested that the determinant of direction of differentiation was associated with Notch signaling pathway.     

Gene expression changes in aging retinal microglia: relationship to microglial support functions and regulation of activation

Microglia, the resident immune cells of the central nervous system (CNS), are thought to contribute to the pathogenesis of age-related neurodegenerative disorders. It has been hypothesized that microglia undergo age-related changes in gene expression patterns that give rise to pathogenic phenotypes. We compared the gene expression profiles in microglia isolated ex vivo from the retinas of mice ranging from early adulthood to late senescence. We discovered that microglial gene expression demonstrated progressive change with increasing age, and involved genes that regulate microglial supportive functions and immune activation. Molecular pathways involving immune function and regulation, angiogenesis, and neurotrophin signaling demonstrated age-related change. In particular, expression levels of complement genes, C3 and CFB, previously associated with age-related macular degeneration (AMD), increased with aging, suggesting that senescent microglia may contribute to complement dysregulation during disease pathogenesis. Taken together, senescent microglia demonstrate age-related gene expression changes capable of altering their constitutive support functions and regulation of their activation status in ways relating to neuroinflammation and neurodegeneration in the CNS.     

Preoperative oral rehydration therapy with 2.5 % carbohydrate beverage alleviates insulin action in volunteers

Preoperative carbohydrate loading enhances insulin action by approximately 50 %. In some Japanese hospitals, preoperative oral rehydration therapy is performed for preventing dehydration during surgery. We hypothesized that preoperative oral rehydration therapy with a 2.5 % carbohydrate beverage that is widely used in Japan can enhance insulin action. Therefore, we investigated the effect of this 2.5 % carbohydrate beverage on insulin action in volunteers. Six healthy volunteers participated in this crossover randomized study. The participants were segregated into 2 groups: an oral rehydration therapy with 2.5 % carbohydrate beverage group (group A) and a control group (group B). Subjects in group B were allowed to drink only water from 9 pm the day before the test; conversely, group A fasted from 9 pm onward and drank 500 ml of the beverage containing 2.5 % carbohydrate (OS-1; Otsuka Pharmaceutical Factory, Tokushima, Japan) between 9 and 12 pm and again at 6.30 am. At 8.30 am, a hyperinsulinemic normoglycemic clamp was initiated using an artificial pancreas STG-22 (Nikkiso, Tokyo, Japan). Insulin action was evaluated in both groups using the glucose infusion rate. Blood glucose levels at the initiation of the clamp procedure were similar. However, the glucose infusion rate for group A was significantly higher than that of group B (8.6 ± 1.5 vs. 6.8 ± 2.0 mg/kg/min, p = 0.009). In conclusion, the hyperinsulinemic normoglycemic clamp using an artificial pancreas showed that the administration of a 2.5 % carbohydrate oral rehydration solution for preoperative oral rehydration therapy improves insulin action in volunteers.     

Polygenic expression of teratozoospermia and normal fertility in B10.MOL‐TEN1 mouse strain

Subfertility and infertility are two major reproductive health problems in human and domestic animals. The contribution of the genotype to these conditions is poorly understood. To examine the genetic basis of male subfertility, we analyzed its relationship to sperm morphology in B10.MOL‐TEN1 mice, which shows high‐frequencies (about 50%) of morphologically abnormal sperm. Drastic histological changes were also found in the testis of the B10.MOL‐TEN1. Segregation analysis showed that the abnormal sperm phenotype in B10.MOL‐TEN1 was inherited and was predictably controlled by at least three loci. We also found that male fertility of this strain was normal. These findings indicate a complicated relationship between sperm morphology and male subfertility.     

Downregulation of GSTM2 enhances gemcitabine chemosensitivity of pancreatic cancer in vitro and in vivo

Glutathione-S-transferases (GSTs) not only show cytoprotective role and their involvement in the development of anticancer drug resistance, but also transmit signals that control cell proliferation and apoptosis. However, the role of GST isoforms in chemotherapy resistance remains elusive in pancreatic cancer. Here, we demonstrated that gemcitabine treatment increased the GSTM2 expression in pancreatic cancer cell lines. Knockdown of GSTM2 by siRNA elevated apoptosis and decreased viability of pancreatic cancer cells treated with gemcitabine. Moreover, in vivo experiments further showed that shRNA induced GSTM2 downregulation enhanced drug sensitivity of gemcitabine in orthotopic pancreatic tumor mice. We also found that GSTM2 levels were lower in tumor tissues than in non-tumor tissues and higher GSTM2 expression was significantly associated with longer overall survival. In conclusion, our findings indicate that GSTM2 expression is essential for the survival of pancreatic cancer cells undergoing gemcitabine treatment and leads to chemo resistance. Downregulation of GSTM2 in pancreatic cancer may benefit gemcitabine treatment. GSTM2 expression in patients also shows significant correlation with overall survival. Thus, our study suggests that GSTM2 is a potential target for chemotherapy optimization and prognostic biomarker of pancreatic cancer.