Kazuyoshi Sakai

Phenotypic changes of AADC-only immunopositive premammillary neurons in the brain of laboratory shrew Suncus murinus by systemic administration of monoamine precursors

After 5-hydroxy-L-tryptophan (5-HTP) and L-3,4-dihydroxyphenylalanine (L-DOPA) were injected i.p. in the laboratory shrew Suncus murinus, immunocytochemical and immunofluorescence studies were conducted on continuous or same sections of the brain, using specific anti-tyrosine hydroxylase (TH), anti-aromatic L-amino acid decarboxylase (AADC), anti-dopamine (DA) and anti-serotonin (5-HT) antisera which were produced in our laboratory. The results of double-staining by the immunofluorescence method as well as immunoelectron microscopy strongly indicate that the cells of the premammillary nucleus of the laboratory shrew brain (AADC-only-positive neurons) are capable of synthesizing DA and 5-HT simultaneously upon simultaneous administration of L-dopa and 5-HTP.

Targeted deletion of the C-terminus of the mouse adenomatous polyposis coli tumor suppressor results in neurologic phenotypes related to schizophrenia.

BackgroundLoss of adenomatous polyposis coli (APC) gene function results in constitutive activation of the canonical Wnt pathway and represents the main initiating and rate-limiting event in colorectal tumorigenesis. APC is likely to participate in a wide spectrum of biological functions via its different functional domains and is abundantly expressed in the brain as well as in peripheral tissues. However, the neuronal function of APC is poorly understood. To investigate the functional role of Apc in the central nervous system, we analyzed the neurological phenotypes of Apc1638T/1638T mice, which carry a targeted deletion of the 3′ terminal third of Apc that does not affect Wnt signaling.ResultsA series of behavioral tests revealed a working memory deficit, increased locomotor activity, reduced anxiety-related behavior, and mildly decreased social interaction in Apc1638T/1638T mice. Apc1638T/1638T mice showed abnormal morphology of the dendritic spines and impaired long-term potentiation of synaptic transmission in the hippocampal CA1 region. Moreover, Apc1638T/1638T mice showed abnormal dopamine and serotonin distribution in the brain. Some of these behavioral and neuronal phenotypes are related to symptoms and endophenotypes of schizophrenia.ConclusionsOur results demonstrate that the C-terminus of the Apc tumor suppressor plays a critical role in cognitive and neuropsychiatric functioning. This finding suggests a potential functional link between the C-terminus of APC and pathologies of the central nervous system.

Effectiveness of exercise-induced cytokines in alleviating arthritis symptoms in arthritis model mice

Recently, health awareness in Japan has been increasing and active exercise is now recommended to prevent lifestyle-related diseases. Cytokine activities have many positive effects in maintaining the health of a number of organs in the body. Myokines are cytokines secreted by skeletal muscles in response to exercise stimulation, and have recently generated much attention. Around 700,000 patients in Japan suffer from rheumatoid arthritis, making it the most prevalent autoimmune disease that requires active prevention and treatment. In the present study, a mouse model of spontaneous arthritis (SKG/Jcl) was subjected to continuous exercise stimulation, starting before the disease onset, to examine the effects of anti-inflammatory and inflammatory cytokine secretion on arthritis. For this stimulation, we developed a device that combines shaking and vibration. The results revealed that exercise stimulation delayed the onset of arthritis and slowed its progression. Thickened articular cartilage and multiple aggregates of chondrocytes were also observed. Further, exercise stimulation increased the expression of IL-6, IL-10, and IL-15, and inhibited TNF-α expression. From these results, we infer that the anti-inflammatory effects of IL-6 and IL-10, which showed increased expression upon exercise stimulation, inhibited the inflammatory activity of TNF-α and possibly delayed the onset of arthritis and slowed its progression. Novel methods for preventing and treating arthritis under clinical settings can be developed on the basis of these findings.

POTENTIAL THERAPEUTIC SYSTEM FOR ALZHEIMER’S DISEASE BY REMOVAL OF BLOOD AB: EFFICIENT AB REMOVAL SYSTEM BY ENHANCING ADSORPTION ON HOLLOW FIBERS WITH HEMODIAFILTRATION

postmortem brains of 17 HD patients (mean age at death, 75. 7 6 10.4 years) and 16 age-matched non-HD subjects (79.0 6 12.6 years) were immunostained with the anti-Ab antibodies 4G8 (anti Ab17-24) and DE2 (anti Ab1-16); they were also subjected to silver staining by the periodic acid-methenamine-silver (PAM) and Gallyas-Braak (GB) methods, anti-phospho-PHF-Tau antibody (AT8), anti-glial-fibrillary-acidic-protein (GFAP) antibody for astrocytes, and anti-Iba1 antibody for microglial cells. Results: All cortices of the brains of HD patients exhibited significantly fewer senile plaques than those of non-HD subjects stained with antiAb antibodies. This significant difference was also observed by silver staining. The parietal lobes of HD patients contained significantly fewer plaques compared to those of non-HD subjects. The temporal, frontal, and occipital lobes of HD patients showed a similar tendency, although not significant. However, the hippocampus showed no clear tendency. The number of Iba1 positive cells in the brain significantly increased in HD patients. The results of AT8 immunostaining will be discussed. Conclusions: Ab deposition in the brain was significantly decreased in HD patients who underwent removal of blood Ab three times per week. Therefore, hemodialysis-induced Ab influx into the blood may at least partly be derived from the brain. It suggested that removal of blood Abmight reduce brain Ab burden. Acknowledgment: This work was partly supported by KAKENHI (20509008, 22500419 and 23500531) and Smoking Research Foundation.

Phenotypic changes of AADC-only-immunoreactive cells in the alimentary canal of the laboratory shrew, Suncus murinus , induced by systemic administration of monoamine precursors

In order to elucidate the function of anti-aromatic acid decarboxylase (AADC)-only-positive cells in the alimentary canal, 5-hydroxy-L-tryptophan (5-HTP) or L-3,4-dihydroxyphenylalanine (L-DOPA) was intraperitoneally injected into the laboratory shrew, Suncus murinus, and immunohistochemical studies were conducted on continuous sections of the alimentary canal using specific antisera against tyrosine hydroxylase (TH), AADC, dopamine (DA), and serotonin (5-HT). AADC-only-positive cells localized to the epithelial layer of the alimentary canal from the stomach to the large intestine. These AADC-only-positive cells became DA- and AADC-positive cells after L-DOPA injection, and 5-HT- and AADC-positive cells after 5-HTP injection. These results strongly indicate that the AADC-only-positive cells in the alimentary canal of Suncus murinus are capable of synthesizing DA and 5-HT simultaneously upon administration of L-DOPA and 5-HTP.

The distribution of T lymphocytes, B lymphocytes, and dendritic-like cells of the anal tonsil in the laboratory shrew, Suncus murinus.

We investigated the distribution of T lymphocytes, B lymphocytes, and S‐100 protein‐immunoreactive dendritic‐like in the anal tonsil of the laboratory shrew, Suncus murinus. In adult animals, T lymphocytes were located mainly at the periphery of the anal tonsil, especially around small blood vessels. B lymphocytes were located in the central and subepithelial region of the anal tonsil, which includes primary lymphoid follicles, and in which there are small numbers of scattered T lymphocytes. B and T lymphocytes were distributed over 72.7 and 27.3% of the tonsillar area, respectively. However, their areas of distribution were not clearly distinguished. The areas containing B lymphocytes were enriched in S‐100 protein antibody‐immunoreactive cells, which exhibited a dendritic shape. These S‐100‐positive cells appeared to be identical to the follicular dendritic cells (FDC) seen in the follicles of lymphoid organs. These results suggest that the anal tonsils constitute one of the gut‐associated lymphoid tissues (GALT), and that a function of the anal tonsil includes the capture of intruding antigens that would generate protective antibody responses. Microsc. Res. Tech., 2011.