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Biomedical subjects

Kazuo Oshima

Publications and source records attributed to Kazuo Oshima.

10 recordsLinked to original sources
PubMed2006

Differential distribution of stem cells in the auditory and vestibular organs of the inner ear.

The adult mammalian cochlea lacks regenerative capacity, which is the main reason for the permanence of hearing loss. Vestibular organs, in contrast, replace a small number of lost hair cells. The reason for this difference is unknown. In this work we show isolation of sphere-forming stem cells from the early postnatal organ of Corti, vestibular sensory epithelia, the spiral ganglion, and the stria vascularis. Organ of Corti and vestibular sensory epithelial stem cells give rise to cells that express multiple hair cell markers and express functional ion channels reminiscent of nascent hair cells. Spiral ganglion stem cells display features of neural stem cells and can give rise to neurons and glial cell types. We found that the ability for sphere formation in the mouse cochlea decreases about 100-fold during the second and third postnatal weeks; this decrease is substantially faster than the reduction of stem cells in vestibular organs, which maintain their stem cell population also at older ages. Coincidentally, the relative expression of developmental and progenitor cell markers in the cochlea decreases during the first 3 postnatal weeks, which is in sharp contrast to the vestibular system, where expression of progenitor cell markers remains constant or even increases during this period. Our findings indicate that the lack of regenerative capacity in the adult mammalian cochlea is either a result of an early postnatal loss of stem cells or diminishment of stem cell features of maturing cochlear cells.

Animals↗
PubMed2006

Bone marrow mesenchymal stem cells are progenitors in vitro for inner ear hair cells.

Stem cells have been demonstrated in the inner ear but they do not spontaneously divide to replace damaged sensory cells. Mesenchymal stem cells (MSC) from bone marrow have been reported to differentiate into multiple lineages including neurons, and we therefore asked whether MSCs could generate sensory cells. Overexpression of the prosensory transcription factor, Math1, in sensory epithelial precursor cells induced expression of myosin VIIa, espin, Brn3c, p27Kip, and jagged2, indicating differentiation to inner ear sensory cells. Some of the cells displayed F-actin positive protrusions in the morphology characteristic of hair cell stereociliary bundles. Hair cell markers were also induced by culture of mouse MSC-derived cells in contact with embryonic chick inner ear cells, and this induction was not due to a cell fusion event, because the chick hair cells could be identified with a chick-specific antibody and chick and mouse antigens were never found in the same cell.

Actins↗
PubMed2006

Needleless intranasal administration of HVJ-E containing allergen attenuates experimental allergic rhinitis.

Allergic rhinitis (AR) is one of the most common chronic diseases. Although current medications are highly effective in controlling its symptoms, they do not reverse the allergen-specific hypersensitivities that underlie the disease. Immunoglobulin E is a key mediator of AR, and preventing its production is clinically important. In this study, we developed an efficient needleless intranasal protein delivery system using the hemagglutinating virus of Japan envelope vector (HVJ-E). Intranasal delivery of ovalbumin (OVA) once a week for 3 weeks using this system enhanced OVA-induced interferon-gamma production by murine splenocytes. This treatment also attenuated the OVA-induced release interleukin-4 (IL-4) and IL-5 from splenocytes and the production of plasma OVA-specific immunoglobulin E in OVA-sensitive AR model mice. Thus, allergen-containing HVJ-E may be useful for noninvasive treatment of AR.

Administration, Intranasal↗
PubMed2006

PACSINs bind to the TRPV4 cation channel. PACSIN 3 modulates the subcellular localization of TRPV4.

TRPV4 is a cation channel that responds to a variety of stimuli including mechanical forces, temperature, and ligand binding. We set out to identify TRPV4-interacting proteins by performing yeast two-hybrid screens, and we isolated with the avian TRPV4 amino terminus the chicken orthologues of mammalian PACSINs 1 and 3. The PACSINs are a protein family consisting of three members that have been implicated in synaptic vesicular membrane trafficking and regulation of dynamin-mediated endocytotic processes. In biochemical interaction assays we found that all three murine PACSIN isoforms can bind to the amino terminus of rodent TRPV4. No member of the PACSIN protein family was able to biochemically interact with TRPV1 and TRPV2. Co-expression of PACSIN 3, but not PACSINs 1 and 2, shifted the ratio of plasma membrane-associated versus cytosolic TRPV4 toward an apparent increase of plasma membrane-associated TRPV4 protein. A similar shift was also observable when we blocked dynamin-mediated endocytotic processes, suggesting that PACSIN 3 specifically affects the endocytosis of TRPV4, thereby modulating the subcellular localization of the ion channel. Mutational analysis shows that the interaction of the two proteins requires both a TRPV4-specific proline-rich domain upstream of the ankyrin repeats of the channel and the carboxyl-terminal Src homology 3 domain of PACSIN 3. Such a functional interaction could be important in cell types that show distribution of both proteins to the same subcellular regions such as renal tubule cells where the proteins are associated with the luminal plasma membrane.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Novel therapeutic strategy to treat brain ischemia: overexpression of hepatocyte growth factor gene reduced ischemic injury without cerebral edema in rat model.

BACKGROUND: Although cerebral occlusive disease leads to cerebral ischemic events, an effective treatment has not yet been established. An ideal therapeutic approach to treat ischemia might have both aspects of enhancement of collateral formation and prevention of neuronal death. Hepatocyte growth factor (HGF) is a potent angiogenic factor that also acts as a neurotrophic factor. Thus, in this study, we examined the therapeutic effects of HGF on brain injury in a rat permanent middle cerebral artery occlusion model. METHODS AND RESULTS: Gene transfer into the brain was performed by injection of human HGF gene with hemagglutinating virus of Japan-envelope vector into the cerebrospinal fluid via the cisterna magna. Overexpression of the HGF gene resulted in a significant decrease in the infarcted brain area as assessed by triphenyltetrazolium chloride staining, whereas rats transfected with control vector exhibited a wide area of brain death after 24 hours of ischemia. Consistently, the decrease in neurological deficit was significantly attenuated in rats transfected with the HGF gene at 24 hours after the ischemic event. Stimulation of angiogenesis was also detected in rats transfected with the HGF gene compared with controls. Of importance, no cerebral edema or destruction of the blood-brain barrier was observed in rats transfected with the HGF gene. CONCLUSIONS: Overall, the present study demonstrated that overexpression of the HGF gene attenuated brain ischemic injury in a rat model, without cerebral edema, through angiogenic and neuroprotective actions. In particular, the reduction of brain injury by HGF may provide a new therapeutic option to treat cerebrovascular disease.

Animals↗
PubMed2003

Intrathecal injection of HVJ-E containing HGF gene to cerebrospinal fluid can prevent and ameliorate hearing impairment in rats.

Hearing impairment, which is the most prevalent sensory deficit of human beings, needs a breakthrough in therapeutic technologies. One technology is the usage of a vector system to reach the inner ear, and another is by a therapeutic molecule. Here we developed a novel gene therapy strategy by combining hepatocyte growth factor (HGF) with hemagglutinating virus of Japan envelope (HVJ-E) vector. When HVJ-E containing human HGF gene was injected intrathecally into the cerebrospinal fluid via cisterna magna of rats, the vector reached the inner ear region, and human HGF gene expression was detected in the spiral ganglion cells (SGCs) of the inner ear. Expression of endogenous rat HGF and its receptor, c-Met, was also induced in SGCs by human HGF. Kanamycin treatment results in hearing impairment by inducing degeneration of hair cells (HCs) and apoptosis of SGCs in rats. By HGF gene transfer before kanamycin treatment, both loss of HCs and apoptosis of SGCs were prevented. Furthermore, hearing function, evaluated by auditory brainstem response, was maintained at a normal level. When HGF gene transfer was performed 2 wk after kanamycin treatment, hearing impairment was significantly recovered. These results indicate a novel and effective therapeutic strategy against sensorineural hearing impairment.

Animals↗
PubMed2003

Malignant transformation of thyroid follicular cells by galectin-3.

Galectin-3, a beta-galactoside binding lectin, is highly expressed in thyroid carcinomas of follicular cell origin, whereas neither benign thyroid adenomas nor normal thyroid tissues express galectin-3. We previously showed that antisense inhibition of galectin-3 expression markedly reduced the malignant phenotype of thyroid papillary carcinoma cells. In the present study we transfected galectin-3 cDNA into TAD-2 normal thyroid follicular cells. Stable transfectants expressing galectin-3 acquired the phenotype of serum-independent growth, clonogenicity in soft agar, as well as loss of contact inhibition. We also compared the gene expression profile of the galectin-3 transfectants to that of the vehicle control, which revealed that a series of genes were differentially expressed between the two. They include proliferating cell nuclear antigen, replication factor C, and retinoblastoma genes that participate in G1-S transition. These results indicate the transformation of thyroid follicular cells by galectin-3 and possible involvement of galectin-3 in cell cycle.

Antigens, Polyomavirus Transforming↗
PubMed2003

HVJ-envelope vector for gene transfer into central nervous system.

To overcome some problems of virus vectors, we developed a novel non-viral vector system, the HVJ-envelope vector (HVJ-E). In this study, we investigated the feasibility of gene transfer into the CNS using the HVJ-E both in vitro and in vivo. Using the Venus reporter gene, fluorescence could be detected in cultured rat cerebral cortex neurons and glial cells. In vivo, the reporter gene (Venus) was successfully transfected into the rat brain by direct injection into the thalamus, intraventricular injection, or intrathecal injection, without inducing immunological change. When the vector was injected after transient occlusion of the middle cerebral artery, fluorescence due to EGFP gene or luciferase activity could be detected only in the injured hemisphere. Finally, luciferase activity was markedly enhanced by the addition of 50 U/ml heparin (P<0.01). Development of efficient HVJ-E for gene transfer into the CNS will be useful for research and clinical gene therapy.

Animals↗
PubMed2002

Effects of neonatal hypoxic-ischemic brain injury on skilled motor tasks and brainstem function in adult rats.

In an attempt to establish more sensitive long-term neurofunctional measurements for neonatal hypoxic-ischemic brain injury, we examined skilled motor task and brainstem functions in adult rats after neonatal cerebral hypoxia-ischemia (H-I), using a staircase test and auditory brainstem response (ABR), respectively. Seven-day-old rats underwent a combination of left common carotid artery ligation and exposure to 8% O(2) for 1 h (n=16). The control animals only received sham operation (n=16). At 3 months of age, the staircase test and ABR were performed. In the staircase test, H-I animals showed marked impairment of skilled forelimb use in the side contralateral to the occluded artery, and the degree of brain damage correlated significantly to skilled forelimb use. In the ABR, H-I animals showed brainstem dysfunction assessed by measuring interpeak latencies for waves III-V and I-V. We also examined the brainstem with antibodies specific for activated caspase-3, a protein involved in initiation of apoptosis, and observed that caspase-3 was activated in the ipsilateral inferior colliculus at 24 h after H-I. The present study shows that both the staircase test and ABR are sensitive and objective long-term neurofunctional measurements that can be used in future studies to assess therapeutic intervention in this neonatal cerebral H-I model.

Age Factors↗