Akihiko Ogata

Amelioration of experimental autoimmune encephalomyelitis in C57BL/6 mice by an agonist of peroxisome proliferator-activated receptor-γ

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily, plays a critical role in adipocyte differentiation and glucose homeostasis. It has been implicated that PPAR-gamma functions as a regulator of cellular proliferation and inflammatory responses. In the present study, we examined whether troglitazone, a selective PPAR-gamma agonists, ameliorated experimental autoimmune encephalomyelitis (EAE) induced by administration of myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 in C57BL/6 mice. We found that troglitazone attenuated the inflammation and decreased the clinical symptoms. It was suggested that the amelioration was attributed to the attenuation of pro-inflammatory cytokine gene expressions.

Rat maf related genes: specific expression in chondrocytes, lens and spinal cord

maf is a family of oncogenes originally identified from avian oncogenic retrovirus, AS42, encoding a nuclear bZip transcription factor. We have isolated two maf related cDNA clones, maf-1 and maf-2, from a rat liver cDNA library. Comparison of the sequence homologies of the proteins encoded by maf-1 and maf-2 with those of c-maf and chicken mafB indicated that maf-1 and maf-2 are the rat homologues of mafB and c-maf, respectively. Both genes are expressed at low levels in a wide variety of rat tissues, including spleen, kidney, muscle and liver. Immunohistochemical studies and in situ hybridization analyses show that maf-1 and maf-2 are strongly expressed in the late stages of chondrocyte development in the femur epiphysis and the rib and limb cartilage of 15 day old (E15) embryo in rat. Cartilage cells, induced by subcutaneous implantation of bone morphogenic protein, also expressed maf-1 and maf-2. In situ hybridization analyses of E15 embryos show that both genes are expressed in the eye lens and the spinal cord as well as the cartilage. However, the expression patterns of maf-1 and maf-2 in lens and spinal cord are different.

Macrophage migration inhibitory factor in the cerebrospinal fluid of patients with conventional and optic-spinal forms of multiple sclerosis and neuro-Behcet's disease

Macrophage migration inhibitory factor (MIF) is becoming increasingly recognized as an important regulator of immune and inflammatory responses. It is released by activated T lymphocytes and macrophages and up-regulates the proinflammatory activity of these cells. MIF is required for antigen- and mitogen-driven T cell activation, and stimulates macrophages to release cytokines and nitric oxide. On the basis of the recent suggestion that pharmacological modulation of MIF production and neutralization of its activity may have important implications for treatment of a variety of autoimmune or inflammatory conditions, we determined the level of MIF in the cerebrospinal fluid (CSF) of patients with conventional-form multiple sclerosis (C-MS) and optic-spinal form multiple sclerosis (OpS-MS), and neuro-Behçets disease (NBD). As control, the CSF of patients with non-inflammatory neurological diseases (NIND) was used. The concentration of MIF in CSF samples was significantly elevated in relapsed cases of C-MS (4.13+/-1.07 ng/ml) (mean+/-S.D.) compared with control samples (2.38+/-0.60 ng/ml) (P<0.0001), whereas MIF in the CSF of C-MS patients in remission was not elevated (2.65+/-0.67 ng/ml). The concentration of MIF in the CSF of OpS-MS patients in relapse (5.53+/-1.74 ng/ml) was higher than that of patients with C-MS in relapse (P<0.05). In NBD patients, the concentration of MIF in CSF was significantly elevated (7.47+/-5.61 ng/ml) compared with control samples (P<0.01) and correlated well with cell count in these samples (r=0.910, P<0.005). These results suggest that MIF may play a pivotal role in immune-mediated diseases of the central nervous system, and that MIF may be useful in the study of differences between C-MS and OpS-MS.

A rat model of Parkinson's disease induced by Japanese encephalitis virus.

In Fischer rats infected with Japanese encephalitis virus (JEV) at 13 days after birth and sacrificed 12 weeks later, the major pathological changes resembled those found in Parkinsons disease. Specifically there was neuronal loss with gliosis which was confined mainly to the zona compacta of the substantia nigra, with a notable absence of lesions in the cerebral cortex and cerebellum. Changes were bilateral being most severe in the central part of the zona compacta. Immunohistochemical studies with anti-tyrosine hydroxylase (TH) demonstrated that the number of TH-positive neurons was significantly decreased in the substantia nigra compared to controls, while comparable numbers of TH-positive neurons were found in the basal ganglia in both JEV-treated rats and age-matched controls. JEV-infected rats showed marked bradykinesia, with significant behavioral improvement being observed following administration of L-DOPA. Immunohistochemical studies failed to detect JEV antigens in any region of the rat brain and the JEV genome was undetectable in the substantia nigra and the cerebral cortex using the reverse transcription-polymerase chain reaction (RT-PCR). The findings suggest that JEV infection of rats under the conditions described may serve as a model of virus induced Parkinsons Disease.

Anterior temporal white matter lesions in myotonic dystrophy with intellectual impairment : an MRI and neuropathological study

Abstract We studied 12 patients with myotonic dystrophy using MRI and the Mini-mental state examination (MMSE), to see it specific MRI findings were associated with intellectual impairment. We also compared them with the neuropathological findings in an autopsy case of MD with intellectual impairment. Mild intellectual impairment was found in 8 of the 12 patients. On T 2-weighted and proton density-weighted images, high-intensity areas were seen in cerebral white matter in 10 of the 12 patients. In seven of these, anterior temporal white-matter lesions (ATWML) were found; all seven had mild intellectual impairment (MMSE 22–26), whereas none of the four patients with normal mentation had ATWML. In only one of the eight patients with intellectual impairment were white-matter lesions not found. Pathological findings were severe loss and disordered arrangement of myelin sheaths and axons in addition to heterotopic neurons within anterior temporal white matter. Bilateral ATWML might be a factor for intellectual impairment in MD. The retrospective pathological study raised the possibility that the ATWML are compatible with focal dysplasia of white matter.

Selective vulnerability of spinal motor neurons to reactive dicarbonyl compounds, intermediate products of glycation, in vitro : implication of inefficient glutathione system in spinal motor neurons

We investigated the effects of two reactive dicarbonyl compounds, methylglyoxal (MG) and 3-deoxyglucosone (3-DG), on cultured spinal cord neurons. Incubation of cortical and spinal neurons with MG and 3-DG for 24 h induced neuronal death in a dose-dependent manner. Spinal motor neurons were more vulnerable than spinal non-motor neurons and cortical neurons. Treatments with glutathione (GSH)-augmenting agents showed protective effects against MG and 3-DG neurotoxicity. Motor neurons were better protected than non-motor neurons. Cotreatment, but not pretreatment, of aminoguanidine (AG), a known inhibitor of advanced glycation end-products (AGEs) from crosslinking, showed a protective effect on spinal neurons with no difference in protective rates between motor and non-motor spinal neurons. Treatments with GSH depleting agents enhanced the neurotoxicity of MG and 3-DG on spinal neurons. Motor neurons were more vulnerable than non-motor neurons with GSH-depleting treatments prior to MG and 3-DG exposures. These data demonstrate that spinal motor neurons are more vulnerable to dicarbonyl compounds, and this selectivity might be related to the relatively inefficient GSH system in spinal motor neurons.

Specific tropism of Japanese encephalitis virus for developing neurons in primary rat brain culture

SummaryAmong all the neural cells in fetal rat brain culture developing neurons showed the highest rate of infection by Japanese encephalitis virus (JEV). JEV specifically bound to these cells as measured by immuno-staining. These results indicate that developing neurons are the major target of JEV, and that the initial specific binding of virus to these cells may be one of the reasons for the neurotropism of JEV.

Identification of macrophage migration inhibitory factor mRNA expression in neural cells of the rat brain by in situ hybridization

Macrophage migration inhibitory factor (MIF) has been rediscovered as a hormone and immunomodulator as well as a proinflammatory cytokine. We investigated the expression of MIF protein and mRNA in the rat brain using optimized immunohistochemistry and in situ hybridization, respectively. By immunohistochemical analysis, we found that MIF protein was present in the epithelial cells of the choroid plexus and ependymal cells as well as astrocyte-like cells in the cerebral white matter and cortex. Tissue sections double-stained for glial fibrillary acidic protein (GFAP) and MIF revealed the presence of MIF protein in astrocytes, whereas this protein was scarcely identified in the neurons by staining using an anti-MIF antibody. We also measured the MIF content in the cerebrospinal fluid, which was 15.5 +/- 2.5 ng/ml (mean +/- SEM), comparable to the serum MIF value. In contrast, expression of MIF mRNA was found not only in astrocytes but also in neurons by the in situ hybridization technique. These results suggest that MIF plays a pivotal role as an immunomodulatory cytokine for inflammatory reactions and immune responses in the whole central nervous system.

Japanese encephalitis virus up-regulates expression of macrophage migration inhibitory factor (MIF) mRNA in the mouse brain.

Macrophage migration inhibitory factor (MIF) is known as a proinflammatory cytokine, glucocorticoid-induced immunomodulator, and pituitary hormone, and contributes to broad-spectrum immune and inflammatory response. To investigate the expression of MIF in the central nervous system in an event of viral infection, we evaluated MIF mRNA expression in the mouse brain infected with Japanese encephalitis virus (JEV). In situ hybridization revealed that MIF mRNA expression was significantly up-regulated in the whole brain by intracranial JEV inoculation at 2 days post-inoculation (d.p.i.). Neurons as well as glial cells expressed MIF transcripts in which some of these cells were co-labeled by double staining for JEV antigens and MIF mRNA. At 4 d.p.i., when typical symptoms of encephalitis were observed, JEV antigen-positive cells were much increased in parallel with enhanced MIF mRNA, consistent with the results of Northern blot analysis. Reverse transcription-polymerase chain reaction showed that MIF mRNA was minimally changed at 1 d.p.i. in comparison with that at 0 d.p.i., but markedly up-regulated after 2 d.p.i. and sustained up to 4 d.p.i. On the other hand, a significant increase of tumor necrosis factor (TNF)-alpha mRNA was observed after only 3 d.p.i. These data suggest the possibility that MIF is involved in virus-induced encephalitis with regard to not only immune responses in the early stage, but also the exacerbation of inflammation in concert with TNF-alpha in the late stages. This is the first evidence demonstrating that MIF is up-regulated in the case of virus-induced encephalitis, which should contribute to the further understanding of the pathological mechanism of JEV-induced encephalitis.

Detection of N epsilon-(carboxymethyl)lysine (CML) and non-CML advanced glycation end-products in the anterior horn of amyotrophic lateral sclerosis spinal cord.

INTRODUCTION The involvement of glycation in neurodegenerative diseases such as Alzheimers disease, Parkinsons disease and amyotrophic lateral sclerosis (ALS) was recently indicated. We previously reported the existence of an Amadori product, 1-hexitol-lysine (1-HL), which is formed in the early glycation reaction, in axonal spheroids of the anterior horn of the ALS spinal cord. OBJECTIVE The purpose of the present study was to confirm the occurrence of the later-stage glycation reaction that follows the early glycation reaction and leads to the formation of advanced glycation end products (AGEs). METHOD We examined whether N(epsilon)-(carboxymethyl)lysine (CML) and non-CML AGE are present in ALS spinal cords. RESULTS Immunohistochemical staining with anti-CML antibody revealed intense positivity in the cell bodies of the remaining atrophic motor neurons and in microglia. Microglia were also positive on staining with anti-non-CML antibody. Axonal spheroids were also positive on anti-non-CML-antibody staining. Vascular endothelial cells were slightly stained by both antibodies. CONCLUSIONS The presence of non-CML AGE in the anterior horn of the ALS spinal cord indicates that the later stage of the glycation reaction is involved in the pathology of ALS. The presence of CML in the anterior horn was also confirmed, and this may reflect augmented oxidative stress.