Activity of Rho-family GTPases during cell division as visualized with FRET-based probes

Rho-family GTPases regulate many cellular functions. To visualize the activity of Rho-family GTPases in living cells, we developed fluorescence resonance energy transfer (FRET)–based probes for Rac1 and Cdc42 previously (Itoh, R.E., K. Kurokawa, Y. Ohba, H. Yoshizaki, N. Mochizuki, and M. Matsuda. 2002. Mol. Cell. Biol. 22:6582–6591). Here, we added two types of probes for RhoA. One is to monitor the activity balance between guanine nucleotide exchange factors and GTPase-activating proteins, and another is to monitor the level of GTP-RhoA. Using these FRET probes, we imaged the activities of Rho-family GTPases during the cell division of HeLa cells. The activities of RhoA, Rac1, and Cdc42 were high at the plasma membrane in interphase, and decreased rapidly on entry into M phase. From after anaphase, the RhoA activity increased at the plasma membrane including cleavage furrow. Rac1 activity was suppressed at the spindle midzone and increased at the plasma membrane of polar sides after telophase. Cdc42 activity was suppressed at the plasma membrane and was high at the intracellular membrane compartments during cytokinesis. In conclusion, we could use the FRET-based probes to visualize the complex spatio-temporal regulation of Rho-family GTPases during cell division

The sperm mitochondria-specific translocator has a key role in maternal mitochondrial inheritance.

The mechanism of maternal mitochondrial inheritance in animals involves the selective elimination of sperm mitochondria by the elimination factor of the egg and the sperm mitochondria-specific factor. In vitro fertilization using sperm from isogenic mice incorporating heterospecific mitochondrial DNA (mtDNA) showed that the number of PCR positives of sperm mtDNA in two-cell embryos was significantly increased following sperm incubation with anti-tetratricopeptide repeat-containing protein involved in spermatogenesis (tpis) protein, anti-translocator of mitochondrial outer membrane (Tom) 22 and anti-Tom40 antibodies. The treatment of fertilized eggs with EGTA and other endonuclease inhibitors increased the sperm mtDNA levels. We conclude that the elimination factor, which is probably an endonuclease, is selectively received by the tpis protein of the sperm mitochondrial outer membrane within the egg. It is then transported into the sperm mitochondria by Tom22 and Tom40, where it destroys the sperm mtDNA, establishing the maternal inheritance of mtDNA.The Version of Record (VoR) is available at http://www.cellbiolint.or

Comprehensive Prospective Analysis of the Factors Contributing to Aspiration Pneumonia Following Endoscopic Submucosal Dissection in Patients with Early Gastric Neoplasms

Endoscopic submucosal dissection (ESD) has become the first-line treatment for early gastric neoplasms; however, a subset of patients treated by this method develop aspiration pneumonia. We conducted a comprehensive prospective analysis of the factors contributing to post-ESD aspiration pneumonia in early gastric neoplasms in this study, with special focus on whether pre-treatment oral care can prevent aspiration pneumonia. Sixty-one patients who underwent ESD for gastric neoplasms were randomly assigned to the oral care or control groups. ESD was performed under deep sedation. Of 60 patients whose data were available for analysis, 5 (8.3%) experienced pneumonia confirmed either by chest radiography or computed tomography. Although no difference in the rate of pneumonia was found between the control and oral care groups, the post-oral care bacteria count was significantly higher in the saliva of patients who developed pneumonia compared to those without pneumonia. In addition, the presence of vascular brain diseases and the dose of meperidine were also significantly associated with the occurrence of pneumonia. These results suggest that the number of oral bacteria as well as pre-existing vascular brain diseases and high-dose narcotics can affect the incidence of post-ESD pneumonia

Usefulness of Choline-PET for the detection of residual hemangiopericytoma in the skull base: comparison with FDG-PET

<p>Abstract</p> <p>Background</p> <p>Choline is a new PET tracer that is useful for the detection of malignant tumor. Choline is a precursor of the biosynthesis of phosphatidylcholine, a major phospholipid in the cell membrane of eukaryotic cells. Malignant tumors have an elevated level of phosphatidylcholine in cell membrane. Thus, choline is a marker of tumor malignancy.</p> <p>Method</p> <p>The patient was a 51-year-old man with repeated recurrent hemangiopericytoma in the skull base. We performed Choline-PET in this patient after various treatments and compared findings with those of FDG-PET.</p> <p>Results</p> <p>Choline accumulated in this tumor, but FDG did not accumulate. We diagnosed this tumor as residual hemangiopericytoma and performed the resection of the residual tumor. FDG-PET is not appropriate for skull base tumor detection because uptake in the brain is very strong.</p> <p>Conclusion</p> <p>We emphasize the usefulness of Choline-PET for the detection of residual hemangiopericytoma in the skull base after various treatments, compared with FDG-PET.</p

Evaluation of new prognostic staging systems (SLiDe score) for hepatocellular carcinoma patients who underwent hepatectomy.

BACKGROUND/AIMS: A new prognostic staging system, the SLiDe (S, stage; Li, liver damage; De, des-gamma-carboxy prothrombin) score was recently proposed. We examined 207 HCC patients following hepatic resection to determine the usefulness of this staging system for HCC patients after surgery. METHODOLOGY: Disease-free and overall survival rates were calculated according to the Kaplan-Meier method, and differences between groups were tested for significance using the log-rank test. RESULTS: Regarding disease-free survival, there were no significant differences in survival between SLiDe score 0 vs 1, between score 2 vs 3, and between score 4 vs 5. There were significant differences between 0-1 vs 2-3 (p < 0.01) and between 2-3 vs 4-5 (p < 0.01). Regarding overall survival, there were no significant differences in survival between score 0 vs 1, between score 2 vs 3, and between score 4 vs 5. There were significant differences between 0-1 vs 2-3 (p < 0.05) and between 2-3 vs 4-5 (p < 0.01). CONCLUSIONS: The SLiDe score, a staging system that combines tumor factors, a tumor marker and hepatic function, might be a better predictor of prognosis in HCC patients who have undergone hepatic resection

Genome-Wide Association Study of Schizophrenia in Japanese Population

Schizophrenia is a devastating neuropsychiatric disorder with genetically complex traits. Genetic variants should explain a considerable portion of the risk for schizophrenia, and genome-wide association study (GWAS) is a potentially powerful tool for identifying the risk variants that underlie the disease. Here, we report the results of a three-stage analysis of three independent cohorts consisting of a total of 2,535 samples from Japanese and Chinese populations for searching schizophrenia susceptibility genes using a GWAS approach. Firstly, we examined 115,770 single nucleotide polymorphisms (SNPs) in 120 patient-parents trio samples from Japanese schizophrenia pedigrees. In stage II, we evaluated 1,632 SNPs (1,159 SNPs of p<0.01 and 473 SNPs of p<0.05 that located in previously reported linkage regions). The second sample consisted of 1,012 case-control samples of Japanese origin. The most significant p value was obtained for the SNP in the ELAVL2 [(embryonic lethal, abnormal vision, Drosophila)-like 2] gene located on 9p21.3 (p = 0.00087). In stage III, we scrutinized the ELAVL2 gene by genotyping gene-centric tagSNPs in the third sample set of 293 family samples (1,163 individuals) of Chinese descent and the SNP in the gene showed a nominal association with schizophrenia in Chinese population (p = 0.026). The current data in Asian population would be helpful for deciphering ethnic diversity of schizophrenia etiology

Ablation of Mrds1/Ofcc1 Induces Hyper-γ-Glutamyl Transpeptidasemia without Abnormal Head Development and Schizophrenia-Relevant Behaviors in Mice

Mutations in the Opo gene result in eye malformation in medaka fish. The human ortholog of this gene, MRDS1/OFCC1, is a potentially causal gene for orofacial cleft, as well as a susceptibility gene for schizophrenia, a devastating mental illness. Based on this evidence, we hypothesized that this gene could perform crucial functions in the development of head and brain structures in vertebrates. To test this hypothesis, we created Mrds1/Ofcc1-null mice. Mice were examined thoroughly using an abnormality screening system referred to as “the Japan Mouse Clinic”. No malformations of the head structure, eye or other parts of the body were apparent in these knockout mice. However, the mutant mice showed a marked increase in serum γ-glutamyl transpeptidase (GGT), a marker for liver damage, but no abnormalities in other liver-related measurements. We also performed a family-based association study on the gene in schizophrenia samples of Japanese origin. We found five single nucleotide polymorphisms (SNPs) located across the gene that showed significant transmission distortion, supporting a prior report of association in a Caucasian cohort. However, the knockout mice showed no behavioral phenotypes relevant to schizophrenia. In conclusion, disruption of the Mrds1/Ofcc1 gene elicits asymptomatic hyper-γ-glutamyl-transpeptidasemia in mice. However, there were no phenotypes to support a role for the gene in the development of eye and craniofacial structures in vertebrates. These results prompt further examination of the gene, including its putative contribution to hyper-γ-glutamyl transpeptidasemia and schizophrenia

Association study of the KCNJ3 gene as a susceptibility candidate for schizophrenia in the Chinese population

We recently reported the results of a genome-wide association study (GWAS) of schizophrenia in the Japanese population. In that study, a single nucleotide polymorphism (SNP) (rs3106653) in the KCNJ3 (potassium inwardly rectifying channel, subfamily J, member 3) gene located at 2q24.1 showed association with schizophrenia in two independent sample sets. KCNJ3, also termed GIRK1 or Kir3.1, is a member of the G protein-activated inwardly rectifying K+ channel (GIRK) group. GIRKs are widely distributed in the brain and play an important role in regulating neural excitability through the activation of various G protein-coupled receptors. In this study, we set out to examine this association using a different population. We first performed a gene-centric association study of the KCNJ3 gene, by genotyping 38 tagSNPs in the Chinese population. We detected nine SNPs that displayed significant association with schizophrenia (lowest P = 0.0016 for rs3106658, Global significance = 0.036). The initial marker SNP (rs3106653) examined in our prior GWAS in the Japanese population also showed nominally significant association in the Chinese population (P = 0.028). Next, we analyzed transcript levels in the dorsolateral prefrontal cortex of postmortem brains from patients with schizophrenia and bipolar disorder and from healthy controls, using real-time quantitative RT-PCR. We found significantly lower KCNJ3 expression in postmortem brains from schizophrenic and bipolar patients compared with controls. These data suggest that the KCNJ3 gene is genetically associated with schizophrenia in Asian populations and add further evidence to the “channelopathy theory of psychiatric illnesses”

The Human Polyoma JC Virus Agnoprotein Acts as a Viroporin

Virus infections can result in a range of cellular injuries and commonly this involves both the plasma and intracellular membranes, resulting in enhanced permeability. Viroporins are a group of proteins that interact with plasma membranes modifying permeability and can promote the release of viral particles. While these proteins are not essential for virus replication, their activity certainly promotes virus growth. Progressive multifocal leukoencephalopathy (PML) is a fatal demyelinating disease resulting from lytic infection of oligodendrocytes by the polyomavirus JC virus (JCV). The genome of JCV encodes six major proteins including a small auxiliary protein known as agnoprotein. Studies on other polyomavirus agnoproteins have suggested that the protein may contribute to viral propagation at various stages in the replication cycle, including transcription, translation, processing of late viral proteins, assembly of virions, and viral propagation. Previous studies from our and other laboratories have indicated that JCV agnoprotein plays an important, although as yet incompletely understood role in the propagation of JCV. Here, we demonstrate that agnoprotein possesses properties commonly associated with viroporins. Our findings demonstrate that: (i) A deletion mutant of agnoprotein is defective in virion release and viral propagation; (ii) Agnoprotein localizes to the ER early in infection, but is also found at the plasma membrane late in infection; (iii) Agnoprotein is an integral membrane protein and forms homo-oligomers; (iv) Agnoprotein enhances permeability of cells to the translation inhibitor hygromycin B; (v) Agnoprotein induces the influx of extracellular Ca2+; (vi) The basic residues at amino acid positions 8 and 9 of agnoprotein key are determinants of the viroporin activity. The viroporin-like properties of agnoprotein result in increased membrane permeability and alterations in intracellular Ca2+ homeostasis leading to membrane dysfunction and enhancement of virus release

コウガクブ トクベツケンキュウ ホウコクショ コウガク ニ オケル リッタイガゾウ カイセキシステム ノ カイハツ オウヨウ ニ カンスル ケンキュウ

The great development of computers and their rconnected terminals is producing the development of image technology and also the easy operation by networks for users. Given assistance of the special fiscal 1988 and 1989 budgets in the Faculty of Engineering, Tokyo Institute of Polytechnics, this project started in cooperation with the laboratories interested in the application of the image information. In order to fulfill graphic functions and image processor simultaneously by one system, which will be the most powerful research tool in the near future, IRIS 4D/50GT graphic computer and NEXUS image processor were purchased and connected with VME BUS so that a part of the multi-functional system was completed. As several analysis about the information of the three-dimensional image were conducted using the system, the abstract is reported