[A case of neuronal intranuclear inclusion disease with serial MRI changes observed from before onset of forgetfulness].

A 70-year-old woman presented with a 6-year history of cognitive dysfunction, neurogenic bladder, constipation and recurrent vomiting, and gradual worsening of symptoms. At the first admission to our department, she was also found to have hepatic encephalopathy due to intrahepatic portosystemic shunt. Head MRI revealed abnormal signal intensity at the corticomedullary junction, the splenium of the corpus callosum, and bilateral middle cerebellar peduncles on DWI. She was diagnosed with intranuclear inclusion disease (NIID) based on skin biopsy and genetic testing of NOTCH2NLC. In a retrospective review of serial head MRI findings for ten years, abnormal signal intensity at the corticomedullary junction and the splenium of the corpus callosum on MRI existed prior to the onset of cognitive dysfunction, and expanded gradually. For early diagnosis of NIID, it is important to focus not only on the characteristic high signal intensity at the corticomedullary junction, but also on the signal at the splenium of the corpus callosum from the early stage.

SIRT1 decelerates morphological processing of oligodendrocyte cell lines and regulates the expression of cytoskeleton-related oligodendrocyte proteins.

SIRT1 is involved in the regulation of a variety of biological processes such as metabolism, stress response, autophagy and differentiation. Although progenitor cells of oligodendrocytes (OPCs) express high level of SIRT1, its function on differentiation is unknown. Because we have shown that SIRT1 plays a pivotal role in differentiation of neural precursor cells, we hypothesized that SIRT1 may also participate in the differentiation of oligodendrocytes (OLGs). We examined whether SIRT1 was expressed in two human oligodendrocyte cell lines: KG-1-C and MO 3.13 OLG. Transfection of cell lines with SIRT1-siRNA and SIRT2-siRNA promoted the extension of cellular processes. SIRT1-siRNA and SIRT2-siRNA increased acetyl-α-tubulin level, conversely, over expression of SIRTs resulted in decreased the ratio of acetyl-α-tubulin to α-tubulin. We also found knockdown of SIRT1 and SIRT2 induced overexpression of ßIV-tubulin and tubulin polymerization promoting protein (TPPP) (OLG-specific cytoskeleton-related molecules) that distributed widely in cell bodies. Taken together, SIRT1 may play a role in oligodenroglial differentiation and myelinogenesis.

CD14 and Toll-Like Receptor 4 Promote Fibrillar Aß42 Uptake by Microglia Through A Clathrin-Mediated Pathway.

We previously demonstrated that microglia play an essential role in clearance of amyloid-ß (Aß) in Alzheimer's disease (AD)-like pathology. Our prior work also showed that several receptors expressed on microglia participated in Aß phagocytosis. However, clathrin-mediated endocytosis (CME), which is associated with production and release of Aß in neurons, has received much less attention in the context of microglial Aß uptake. To elucidate the detailed mechanisms of microglial Aß uptake pathways, we focused on CD14 and Toll-like receptor 4 (TLR4), which have been shown to mediate fibrillar Aß1 - 42 (fAß42) phagocytosis in microglia. CD14 has also been known to control lipopolysaccharide-induced internalization of TLR4 in a clathrin-dependent manner. However, it remains unclear whether CD14 and TLR4 engage in CME in microglial fAß42 uptake, including whether CD14 interacts with TLR4 in the process. In the present study, we found that CD14-positive microglia increased in an age-dependent manner in the cortex of AD model mice. Immunostaining showed that CD14 interacted with TLR4 to internalize fAß42 in the mouse microglial cell line MG6. Knock-down of CD14 and TLR4 in MG6 cells significantly reduced intracellular fAß42, showing their involvement in fAß42 uptake. We also found that clathrin participated in fAß42 uptake by MG6 cells. Furthermore, CD14 and TLR4 mediated fAß42 uptake via clathrin-dependent mechanisms. These results indicate that CD14 and TLR4 participate not only in phagocytosis but also in clathrin-dependent fAß42 internalization in microglia. These findings provide novel molecular understanding of microglial fAß42 uptake, which could be of therapeutic relevance for AD.

Evaluation of Mitochondrial Oxidative Stress in the Brain of a Transgenic Mouse Model of Alzheimer's Disease by in vitro Electron Paramagnetic Resonance Spectroscopy.

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases responsible for progressive dementia. Deposition of amyloid-ß (Aß) in the brain is the most important pathophysiological hallmark of AD. In addition, recent evidence indicates that reactive oxygen species (ROS) derived from mitochondria contribute to progression of AD pathology. We thus hypothesized that Aß accumulates and oxidative stress increases in the brain mitochondria of a transgenic mouse model of AD (APdE9). We measured the quantity of Aß and the activity of the antioxidant enzyme superoxide dismutase (SOD) in brain mitochondrial fractions prepared from APdE9 and wild-type (WT) mice aged 6, 9, 15, and 18 months. We also quantified the age-related changes in redox status in the mitochondrial fractions obtained from both APdE9 and WT mouse brains by electron paramagnetic resonance (EPR) spectrometry using a paramagnetic nitroxide "Mito-Tempo" [(2-(2,2,6,6-Tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl) triphenylphosphonium chloride monohydrate] as a mitochondria-targeted redox-sensitive probe. In APdE9 mice, Aß accumulated in brain mitochondria earlier than in the non-mitochondrial fraction of the brain. Furthermore, increased oxidative stress was demonstrated in brain mitochondria of APdE9 mice by in vitro SOD assay as well as EPR spectroscopy. EPR combined with a mitochondria-targeted redox-sensitive nitroxide probe is a potentially powerful tool to elucidate the etiology of AD and facilitate the development of new therapeutic strategies for AD.

Role of Suppressor of Cytokine Signaling 3 (SOCS3) in Altering Activated Microglia Phenotype in APPswe/PS1dE9 Mice.

In response to changes of the central nervous system environment, microglia are capable of acquiring diverse phenotypes for cytotoxic or immune regulation and resolution of injury. Alzheimer's disease (AD) pathology also induces several microglial activations, resulting in production of pro-inflammatory cytokines and reactive oxygen species or clearance of amyloid-ß (Aß) through phagocytosis. We previously demonstrated that microglial activation and increase in oxidative stress started from the middle age in APPswe/PS1dE9 mice, and hypothesized that M1 activation occurs in middle-aged AD mice by Aß stimulation. In the present study, we analyzed in vivo expressions of pro-inflammatory cytokines (M1 microglial markers), M2 microglial markers, and suppressor of cytokine signaling (SOCS) family, and examined the microglial phenotypic profile in APPswe/PS1dE9 mice. Then we compared the in vitro gene expression patterns of Aß- and lipopolysaccharide (LPS)-stimulated primary-cultured microglia. Microglia in APPswe/PS1dE9 mice exhibited an M1-like phenotype, expressing tumor necrosis factor α (TNFα) but not interleukin 6 (IL6). Aß-stimulated primary-cultured microglia also expressed TNFα but not IL6, whereas LPS-stimulated primary-cultured microglia expressed both pro-inflammatory cytokines. Furthermore, both microglia in APPswe/PS1dE9 mice and Aß-stimulated primary-cultured microglia expressed SOCS3. Reduction of SOCS3 expression in Aß-challenged primary-cultured microglia resulted in upregulation of IL6 expression. Our findings indicate that SOCS3 suppresses complete polarization to M1 phenotype through blocking IL6 production, and Aß-challenged primary-cultured microglia replicate the in vivo gene expression pattern of microglia in APPswe/PS1dE9 mice. Aß may induce the M1-like phenotype through blocking of IL6 by SOCS3.

A case of neuromyelitis optica presenting marked pleocytosis and hypoglycorrhachia.

A 57-year-old man initially developed chest discomfort, nausea, vomiting, headache and low-grade fever, followed by paraplegia, sensory disturbance below level Th5 and bilateral visual loss. He was admitted to our hospital on the 15th day of illness. MRI short T1 inversion recovery image showed multiple longitudinal lesions in the spinal cord below C3, and T2-weighted image showed abnormal hyperintensity within the left optic nerve. Cerebrospinal fluid (CSF) analysis revealed marked pleocytosis (1,719/µl) and hypoglycorrhachia (CSF glucose; 20 mg/dl). Intensive immunosuppressive therapy combined with antibiotics and antiviral agent were started immediately, resulting in relatively good visual outcome but no improvement of paraplegia and sensory disturbance. The patient's serum sample on admission was subsequently reported to be positive for anti-aquaporin-4 antibody. With no evidence of infectious diseases, neuromyelitis optica (NMO) was diagnosed. It should be borne in mind that marked hypogylcorrhachia may also be seen in NMO.

[A case of dural arteriovenous fistula of right cavernous sinus presenting bilateral eye symptoms].

An 85-year-old woman was first admitted to our hospital because of right ptosis and diplopia. Examinations showed right oculomotor paralysis and reduced vision in the right eye. Serological and neuroradiological examinations failed to reveal the etiology. Oral prednisolone was started for a presumptive diagnosis of idiopathic oculomotor nerve palsy, which resulted in little improvement. Approximately ten months after the first admission, left ptosis appeared and she was re-admitted to our hospital. One day after admission, external ophthalmoplegia and conjunctival injection on the left side appeared. MRI revealed abnormal flow void in the right cavernous sinus. Based on cerebral angiographic findings, dural arteriovenous fistula of the right cavernous sinus was diagnosed. Symptoms on the left side were considered to result from increased perfusion pressure due to venous drainage via the intercavernous sinus to the contralateral cavernous sinus. After transvenous embolization, symptoms and signs improved gradually. In a case of external ophthalmoplegia with unknown etiology, detailed neuroradiologyical examinations such as cerebral angiogram are advisable.