112 research outputs found
Prevention of Hepatocellular Carcinoma Development Associated with Chronic Hepatitis by Anti-Fas Ligand Antibody Therapy
A persistent immune response to hepatitis viruses is a well-recognized risk factor for hepatocellular carcinoma. However, the molecular and cellular basis for the procarcinogenic potential of the immune response is not well defined. Here, using a unique animal model of chronic hepatitis that induces hepatocellular carcinogenesis, we demonstrate that neutralization of the activity of Fas ligand prevented hepatocyte apoptosis, proliferation, liver inflammation, and the eventual development of hepatocellular carcinoma. The results indicate that Fas ligand is involved not only in direct hepatocyte killing but also in the process of inflammation and hepatocellular carcinogenesis in chronic hepatitis. This is the first demonstration that amelioration of chronic inflammation by some treatment actually caused reduction of cancer development
Foxp2 Regulates Identities and Projection Patterns of Thalamic Nuclei during Development
The molecular mechanisms underlying the formation of the thalamus during development have been investigated intensively. Although transcription factors distinguishing the thalamic primordium from adjacent brain structures have been uncovered, those involved in patterning inside the thalamus are largely unclear. Here, we show that Foxp2, a member of the forkhead transcription factor family, regulates thalamic patterning during development. We found a graded expression pattern of Foxp2 in the thalamic primordium of the mouse embryo. The expression levels of Foxp2 were high in the posterior region and low in the anterior region of the thalamic primordium. In Foxp2 (R552H) knockin mice, which have a missense loss-of-function mutation in the forkhead domain of Foxp2, thalamic nuclei of the posterior region of the thalamus were shrunken, while those of the intermediate region were expanded. Consistently, Foxp2 (R552H) knockin mice showed changes in thalamocortical projection patterns. Our results uncovered important roles of Foxp2 in thalamic patterning and thalamocortical projections during development. © 2017 Author.Embargo Period 12 month
Cadm1-Expressing Synapses on Purkinje Cell Dendrites Are Involved in Mouse Ultrasonic Vocalization Activity
Foxp2(R552H) knock-in (KI) mouse pups with a mutation related to human speech–language disorders exhibit poor development of cerebellar Purkinje cells and impaired ultrasonic vocalization (USV), a communication tool for mother-offspring interactions. Thus, human speech and mouse USV appear to have a Foxp2-mediated common molecular basis in the cerebellum. Mutations in the gene encoding the synaptic adhesion molecule CADM1 (RA175/Necl2/SynCAM1/Cadm1) have been identified in people with autism spectrum disorder (ASD) who have impaired speech and language. In the present study, we show that both Cadm1-deficient knockout (KO) pups and Foxp2(R552H) KI pups exhibit impaired USV and smaller cerebellums. Cadm1 was preferentially localized to the apical–distal portion of the dendritic arbor of Purkinje cells in the molecular layer of wild-type pups, and VGluT1 level decreased in the cerebellum of Cadm1 KO mice. In addition, we detected reduced immunoreactivity of Cadm1 and VGluT1 on the poorly developed dendritic arbor of Purkinje cells in the Foxp2(R552H) KI pups. However, Cadm1 mRNA expression was not altered in the Foxp2(R552H) KI pups. These results suggest that although the Foxp2 transcription factor does not target Cadm1, Cadm1 at the synapses of Purkinje cells and parallel fibers is necessary for USV function. The loss of Cadm1-expressing synapses on the dendrites of Purkinje cells may be associated with the USV impairment that Cadm1 KO and Foxp2(R552H) KI mice exhibit
Fractional S^z excitation and its bound state around the 1/3 plateau of the S=1/2 Ising-like zigzag XXZ chain
We present the microscopic view for the excitations around the 1/3 plateau
state of the Ising-like zigzag XXZ chain. We analyze the low-energy excitations
around the plateau with the degenerating perturbation theory from the Ising
limit, combined with the Bethe-form wave function. We then find that the
domain-wall particles carrying and its bound state of describe well the low-energy excitations around the 1/3 plateau state. The
formation of the bound state of the domain-walls clearly provides the
microscopic mechanism of the cusp singularities and the even-odd behavior in
the magnetization curve.Comment: 13 pages, 15 figure
A rat model of human FENIB (familial encephalopathy with neuroserpin inclusion bodies)
金沢大学大学院医学系研究科脳細胞分子学FENIB (familial encephalopathy with neuroserpin inclusion bodies) is caused by intracellular accumulation/polymerization of mutant neuroserpins in the endoplasmic reticulum (ER). Transgenic rats overexpressing megsin (Tg meg), a newly identified serine protease inhibitor (serpin), demonstrated intraneuronal periodic-acid Schiff (PAS)-positive inclusions distributed throughout deeper layers of cerebral cortex, CA1 of the hippocampus, and substantia nigra. Hippocampal extracts from Tg meg rats showed increased expression of ER stress proteins, and activation of caspases-12 and -3, associated with decreased neuronal density. Enhanced ER stress was also observed in dopaminergic neurons in the substantia nigra, in parallel with decreased neuronal viability and motor coordination. In each case, PAS-positive inclusions were also positive for megsin. These data suggest that overexpression of megsin results in ER stress, eventuating in the formation of PAS-positive inclusions. Tg meg rats provide a novel model of FENIB, where accumulation of serpins in the ER induces selective dysfunction/loss of specific neuronal populations. © 2006 Elsevier Inc. All rights reserved
Colossal Magnetoresistant Materials: The Key Role of Phase Separation
The study of the manganese oxides, widely known as manganites, that exhibit
the ``Colossal'' Magnetoresistance (CMR) effect is among the main areas of
research within the area of Strongly Correlated Electrons. After considerable
theoretical effort in recent years, mainly guided by computational and
mean-field studies of realistic models, considerable progress has been achieved
in understanding the curious properties of these compounds. These recent
studies suggest that the ground states of manganite models tend to be
intrinsically inhomogeneous due to the presence of strong tendencies toward
phase separation, typically involving ferromagnetic metallic and
antiferromagnetic charge and orbital ordered insulating domains. Calculations
of the resistivity versus temperature using mixed states lead to a good
agreement with experiments. The mixed-phase tendencies have two origins: (i)
electronic phase separation between phases with different densities that lead
to nanometer scale coexisting clusters, and (ii) disorder-induced phase
separation with percolative characteristics between equal-density phases,
driven by disorder near first-order metal-insulator transitions. The coexisting
clusters in the latter can be as large as a micrometer in size. It is argued
that a large variety of experiments reviewed in detail here contain results
compatible with the theoretical predictions. It is concluded that manganites
reveal such a wide variety of interesting physical phenomena that their
detailed study is quite important for progress in the field of Correlated
Electrons.Comment: 76 pages, 21 PNG files with figures. To appear in Physics Report
WDR55 Is a Nucleolar Modulator of Ribosomal RNA Synthesis, Cell Cycle Progression, and Teleost Organ Development
The thymus is a vertebrate-specific organ where T lymphocytes are generated. Genetic programs that lead to thymus development are incompletely understood. We previously screened ethylnitrosourea-induced medaka mutants for recessive defects in thymus development. Here we report that one of those mutants is caused by a missense mutation in a gene encoding the previously uncharacterized protein WDR55 carrying the tryptophan-aspartate-repeat motif. We find that WDR55 is a novel nucleolar protein involved in the production of ribosomal RNA (rRNA). Defects in WDR55 cause aberrant accumulation of rRNA intermediates and cell cycle arrest. A mutation in WDR55 in zebrafish also leads to analogous defects in thymus development, whereas WDR55-null mice are lethal before implantation. These results indicate that WDR55 is a nuclear modulator of rRNA synthesis, cell cycle progression, and embryonic organogenesis including teleost thymus development
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