Kumamoto University

About: Kumamoto University is a education organization based out in Kumamoto, Kumamoto, Japan. It is known for research contribution in the topics: Population & Cancer. The organization has 19602 authors who have published 35513 publications receiving 901260 citations. The organization is also known as: Kumamoto Daigaku.

Differential Roles of Interleukin 15 mRNA Isoforms Generated by Alternative Splicing in Immune Responses in Vivo

Abstract: At least two types of interleukin (IL)-15 mRNA isoforms are generated by alternative splicing at the 5′ upstream of exon 5 in mice. To elucidate the potential roles of IL-15 isoforms in immune responses in vivo, we constructed two groups of transgenic mice using originally described IL-15 cDNA with a normal exon 5 (normal IL-15 transgenic [Tg] mice) and IL-15 cDNA with an alternative exon 5 (alternative IL-15 Tg mice) under the control of an MHC class I promoter. Normal IL-15 Tg mice constitutionally produced a significant level of IL-15 protein and had markedly increased numbers of memory type (CD44high Ly6C+) of CD8+ T cells in the LN. These mice showed resistance to Salmonella infection accompanied by the enhanced interferon (IFN)-γ production, but depletion of CD8+ T cells exaggerated the bacterial growth, suggesting that the IL-15–dependent CD8+ T cells with a memory phenotype may serve to protect against Salmonella infection in normal IL-15 Tg mice. On the other hand, a large amount of intracellular IL-15 protein was detected but hardly secreted extracellularly in alternative IL-15 Tg mice. Although most of the T cells developed normally in the alternative IL-15 Tg mice, they showed impaired IFN-γ production upon TCR engagement. The alternative IL-15 transgenic mice were susceptible to Salmonella accompanied by impaired production of endogenous IL-15 and IFN-γ. Thus, two groups of IL-15 Tg mice may provide information concerning the different roles of IL-15 isoforms in the immune system in vivo.

Novel somatic and germline mutations in intracranial germ cell tumours

Abstract: Intracranial germ cell tumours (IGCTs) are a group of rare heterogeneous brain tumours that are clinically and histologically similar to the more common gonadal GCTs. IGCTs show great variation in their geographical and gender distribution, histological composition and treatment outcomes. The incidence of IGCTs is historically five- to eightfold greater in Japan and other East Asian countries than in Western countries, with peak incidence near the time of puberty. About half of the tumours are located in the pineal region. The male-to-female incidence ratio is approximately 3-4:1 overall, but is even higher for tumours located in the pineal region. Owing to the scarcity of tumour specimens available for research, little is currently known about this rare disease. Here we report the analysis of 62 cases by next-generation sequencing, single nucleotide polymorphism array and expression array. We find the KIT/RAS signalling pathway frequently mutated in more than 50% of IGCTs, including novel recurrent somatic mutations in KIT, its downstream mediators KRAS and NRAS, and its negative regulator CBL. Novel somatic alterations in the AKT/mTOR pathway included copy number gains of the AKT1 locus at 14q32.33 in 19% of patients, with corresponding upregulation of AKT1 expression. We identified loss-of-function mutations in BCORL1, a transcriptional co-repressor and tumour suppressor. We report significant enrichment of novel and rare germline variants in JMJD1C, which codes for a histone demethylase and is a coactivator of the androgen receptor, among Japanese IGCT patients. This study establishes a molecular foundation for understanding the biology of IGCTs and suggests potentially promising therapeutic strategies focusing on the inhibition of KIT/RAS activation and the AKT1/mTOR pathway.

The prognostic significance of lymph node metastasis and intrapancreatic perineural invasion in pancreatic cancer after curative resection

Abstract: To investigate the prognostic factors of pancreatic cancer, a retrospective analysis of 193 patients who underwent curative resection was conducted. Of the 193 patients, 38 (20%) survived for more than 5 years, the 5-year survival rates for stages I, II, III, and IV disease being 41%, 17% 11%, and 6%, respectively. According to a multivariate analysis, lymph node metastasis, intrapancreatic perineural invasion, and portal vein invasion were significant prognostic factors. Subsequently, a subgroup analysis concerning nodal metastasis and intrapancreatic perineural invasion was performed in 126 patients with records of these histological findings. In the group of patients without nodal metastasis, the 5-year survival rate for those without perineural invasion was 75%, whereas that for those with perineural invasion was 29%, the difference in survival of these subgroups being significant (P<0.02). In the group of patients with nodal metastasis, the 5-year survival rate for those without perineural invasion was 17%, while that for those with perineural invasion was 10%. The most favorable 5-year survival of 89% was observed in the subgroup of patients with stage I disease without perineural invasion. Thus, pancreatic adenocarcinoma categorized by the combination of these independent types of biological behavior showed 5-year survival rates ranging from very high to low, indicating that these two factors play an important role in the prognosis of this disease.

The origin, migration and fine morphology of human primordial germ cells

Abstract: Human primordial germ cells (PGCs) were observed ultrastructurally in stages from their endodermal to gonadal locations. Primitive PGCs in the hind-gut epithelium of the 4-week embryo, were recognized as well demarcated cells from the neighboring cells. At the time fo separation, the basal lamina of the epithelium was broken, then, through the gap so opened, the PGCs started to escape into the outer mesenchyme. In embryos at five weeks, PGCs were in the migration stage, and were found in the dorsal mesentery, at the coelomic angle and in the forming germinal ridge. In embryos at six weeks or later, almost all PGCS were accumulated in the gonad. The PGC was characterized by its large size and the large and round nucleus with conspicuous nucleolus, and by the presence of abundant glycogen particles and a considerable number of lipid droplets in the cytoplasm. Alkaline phosphatase activity was demonstrated selectively on the plasma membrane of the PGC. The shape of PGC was irregular, often had pseudopodia in PGCs in the separation and migration stages, suggesting their amoeboid movement in vivo, but was generally round or elliptic in PGCs in the settlement stage. The PGC was usually surrounded by and in close association with adjacent somatic cells.