Roles of Microglia in Neurodegenerative Diseases

In recent years, microglia have attracted attention owing to their roles in various neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Microglia, which are brain-resident macrophages, not only act as immune cells but also perform other functions in the body. Interestingly, they exert contrasting effects on different neurodegenerative diseases. In addition to the previously reported M1 (toxic) and M2 (protective) types, microglia now also include disease-associated microglia owing to a more elaborate classification. Understanding this detailed classification is necessary to elucidate the association between microglia and neurodegenerative diseases. In this review, we discuss the diverse roles of microglia in neurodegenerative diseases and highlight their potential as therapeutic targets.

High Glucose-stimulated aPKC Activation Promotes Pancreatic Cancer Cell Progression Through YAP Signaling

BACKGROUND/AIM

Persistent hyperglycemia caused by diabetes mellitus is a risk factor for pancreatic cancer (PC). We have previously reported that aberrant activation of atypical protein kinase C (aPKC) enhances PC cell progression. However, no reports have elucidated whether hyperglycemia promotes PC cell progression and whether aPKC activation is related to PC cell progression mechanisms.

MATERIALS AND METHODS

We examined whether high-glucose stimulation accelerates PC cell proliferation, migration, and invasion. Furthermore, to determine whether PC cells activate aPKC upon high-glucose stimulation, we measured the phosphorylation of aPKC at T560 in PC cells.

RESULTS

High-glucose stimulation accelerated PC cell proliferation, migration, and invasion. High-glucose treatment increased aPKC's activated form, with T560 phosphorylation, in PC cells. However, aPKC knockdown attenuated these effects. aPKC reportedly induces cell transformation through Yes-associated protein (YAP) activation. YAP expression was increased in high glucose-treated PC cells but not in aPKC-knockdown cells. aPKC interacts with partitioning defective 3 (Par-3), which aids in establishing cell polarity and inhibits aPKC by binding as a substrate. In Par-3-knockdown PC cells, YAP expression increased independently of high-glucose treatment. Over-expression of Par-3 and aPKC-dominant negative mutants prevented the high glucose-stimulated nuclear localization of YAP. YAP forms a complex with the zinc finger E-box binding homeobox 1 protein (ZEB1), an activator of epithelial-mesenchymal transition. ZEB1 expression was increased by high glucose treatment or Par-3 knockdown, but aPKC knockdown suppressed this increase.

CONCLUSION

High glucose-induced aPKC activation promotes PC progression by enhancing the YAP signaling pathway.

TYRO3 promotes chemoresistance via increased LC3 expression in pancreatic cancer

Pancreatic cancer (PC) is an aggressive malignancy with few treatment options, and improved treatment strategies are urgently required. TYRO3, a member of the TAM receptor tyrosine kinase family, is a known oncogene; however, the relationship between TYRO3 expression and PC chemoresistance remains to be elucidated. We performed gain- and loss-of-function experiments on TYRO3 to examine whether it is involved in chemoresistance in PC cells. TYRO3 knockdown decreased cell viability and enhanced apoptosis following treatment of PC cells with gemcitabine and 5-fluorouracil (5-FU). In contrast, no such effects were observed in TYRO3-overexpressing PC cells. It is known that autophagy is associated with cancer chemoresistance. We then examined effects of TYRO3 on autophagy in PC cells. TYRO3 overexpression increased LC3 mRNA levels and induced LC3 puncta in PC cells. Inhibition of autophagy by chloroquine mitigated cell resistance to gemcitabine and 5-FU. In a xenograft mouse model, TYRO3 silencing significantly increased sensitivity of the cells to gemcitabine and 5-FU. To further investigate the involvement of autophagy in patients with PC, we immunohistochemically analyzed LC3 expression in the tissues of patients who underwent pancreatectomy and compared it with disease prognosis and TYRO3 expression. LC3 expression was negatively and positively correlated with prognosis and TYRO3 expression, respectively. Furthermore, LC3- and TYRO3-positive patients had a significantly worse prognosis among patients with PC who received chemotherapy after recurrence. These results indicated that the TYRO3-autophagy signaling pathway confers PC resistance to gemcitabine and 5-FU, and could be a novel therapeutic target to resolve PC chemoresistance.

Molecular mechanisms underlying the promotion of wound repair by coenzyme Q10: PI3K/Akt signal activation via alterations to cell membrane domains

Coenzyme Q10 (CoQ10) promotes wound healing in vitro and in vivo. However, the molecular mechanisms underlying the promoting effects of CoQ10 on wound repair remain unknown. In the present study, we investigated the molecular mechanisms through which CoQ10 induces wound repair using a cellular wound-healing model. CoQ10 promoted wound closure in a dose-dependent manner and wound-mediated cell polarization after wounding in HaCaT cells. A comparison with other CoQ homologs, benzoquinone derivatives, and polyisoprenyl compounds suggested that the whole structure of CoQ10 is required for potent wound repair. The phosphorylation of Akt after wounding and the plasma membrane translocation of Akt were elevated in CoQ10-treated cells. The promoting effect of CoQ10 on wound repair was abrogated by co-treatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor. Immuno­histochemical and biochemical analyses showed that CoQ10 increased the localization of caveolin-1 (Cav-1) to the apical membrane domains of the cells and the Cav-1 content in the membrane-rich fractions. Depletion of Cav-1 suppressed CoQ10-mediated wound repair and PI3K/Akt signaling activation in HaCaT cells. These results indicated that CoQ10 increases the translocation of Cav-1 to the plasma membranes, activating the downstream PI3K/Akt signaling pathway, and resulting in wound closure in HaCaT cells.

Oncogenic role of TYRO3 receptor tyrosine kinase in the progression of pancreatic cancer

The expression and functions of TYRO3, a member of the TAM receptor tyrosine kinase family, in pancreatic cancer (PC) have not been specifically elucidated. In this study, we confirmed TYRO3 expression in five human PC cell lines (PANC-1, MIA PaCa-2, BxPC-3, AsPC-1, and PK-9) using Western blotting. TYRO3 silencing and overexpression studies have revealed that TYRO3 promotes cell proliferation and invasion in PC via phosphorylation of protein kinase B (Akt) and extracellular signal-regulated kinase (ERK). Using a mouse xenograft model, we showed that tumor growth was significantly suppressed in mice subcutaneously inoculated with TYRO3-knockdown PC cells compared with mice inoculated with control PC cells. Furthermore, TYRO3 expression was examined in PC tissues obtained from 106 patients who underwent pancreatic resection for invasive ductal carcinoma through immunohistochemical staining. TYRO3-positive patients had poor prognoses for overall survival and disease-specific survival compared with TYRO3-negative patients. Multivariate analysis revealed that TYRO3 expression is an independent prognostic factor for overall survival. Our study demonstrates the critical role of TYRO3 in PC progression through Akt and ERK activation and suggests TYRO3 as a novel promising target for therapeutic strategies against PC.

α-Tocopherol promotes HaCaT keratinocyte wound repair through the regulation of polarity proteins leading to the polarized cell migration

In many developed countries including Japan, how to care the bedridden elderly people with chronic wounds such as decubitus becomes one of the most concerned issues. Although antioxidant micronutrients including vitamin E, especially α-tocopherol (α-Toc), are reported to shorten a period of wound closure, the promoting effect of α-Toc on wound healing independent of its antioxidant activity remains to be fully elucidated. The aim of this study was to examine whether α-Toc affects wound-mediated HaCaT keratinocyte polarization process including the recruitment of polarity regulating proteins, leading to wound repair independently of its antioxidant activity. We investigated the effects of α-Toc and other antioxidants such as Trolox, a cell-permeable α-Toc analog on the migration, proliferation, and cell polarization of HaCaT keratinocytes after wounding. We analyzed the localization and complex formation of polarity proteins, partitioning defective 3 (Par3), and atypical protein kinase C (aPKC), and aPKC activity by immunohistochemistry, immunoprecipitation analyses, and in vitro kinase assays, respectively. α-Toc but not other antioxidants enhanced the wound closure and cell polarization in HaCaT keratinocytes after wounding. α-Toc regulated the localization and complex formation of Par3 and aPKC during wound healing. Knockdown of aPKC or Par3 abrogated α-Toc-mediated promotion of the wound closure and cell polarization in HaCaT keratinocytes. Furthermore, aPKC kinase activity was significantly increased in α-Toc-treated cells through activation of phosphatidylinositol 3-kinase/Akt signaling pathway. These results suggest that α-Toc promotes HaCaT keratinocyte wound repair by regulating the aPKC kinase activity and the formation of aPKC-Par3 complex. © 2017 BioFactors, 44(2):180-191, 2018.

Preconditioning by Low Dose LPS Prevents Subsequent LPS-Induced Severe Liver Injury via Nrf2 Activation in Mice

BACKGROUND

Sepsis is a syndrome triggered by endotoxin lipopolysaccharide (LPS) during bacterial infection. Sepsis sometimes recurs, with the second sepsis giving rise to a different phenotype because of disease modification by the preceding sepsis. Such a protective modification is called a preconditioning (PC) effect. PC is an endogenous protective mechanism by which sublethal damage confers tolerance to a subsequent lethal load. Oxidative stress is one of the important pathogenetic mechanisms that occur in sepsis. The nuclear factor erythroid 2 (NF-E2)-related factor-2 (Nrf2) system is a key regulatory transcription factor that protects organs and cells against oxidative stress and may be associated with the PC effect in repeated sepsis.

METHODS

The effect of PC induced by low-dose LPS on survival rate and liver injury against subsequent high-dose LPS stimulation was examined using a mouse model of sepsis. In order to understand the detailed mechanism(s) involved in the PC effect within the liver, gene expression array was performed. As a candidate mechanism of PC, the activation of the Nrf2 system was analyzed using Nrf2 reporter mice. Furthermore, the induction of heme oxygenase-1 (HO-1), one of the main targets of Nrf2, in the liver was examined by immunoblotting and immunohistochemistry. The PC effect on liver injury induced by LPS was further examined using Nrf2-deficient mice.

RESULTS

PC by LPS (1.7 or 5.0 mg/kg body weight, intraperitoneally) increased the survival rate of mice and decreased liver injury in response to a subsequent injection of a lethal level of LPS (20 mg/kg body weight). DNA array revealed that the gene ontology term "antioxidant activity" as one of the candidate mechanisms of the PC effect by LPS. In Nrf2 reporter mice, PC immediately and intensely enhanced luminescence that indicated Nrf2 activation after subsequent LPS injection. The induction of HO-1 by LPS was also enhanced by preceding PC, and its induction was observed mainly in Kupffer cells of the liver. In Nrf2-deficient mice, the induction of HO-1 in Kupffer cells and the hepatoprotective effect of PC were decreased as compared with wild-type mice.

CONCLUSION

Our results suggest that activation of the Nrf2 system is, at least in part, one of the mechanisms of a PC effect in the mouse liver in the case of repeated LPS stimulation.

Rice Bran Dietary Supplementation Improves Neurological Symptoms and Loss of Purkinje Cells in Vitamin E-Deficient Mice

BACKGROUND

Vitamin E (VE, α-tocopherol) is a fat-soluble vitamin and is well known as an antioxidant. A deficiency in VE induces oxidative stress in the brain and causes motor and memory dysfunction. The consumption of a VE-rich diet has been given much attention in recent years, in regards to anti-aging and the prevention of age-related neuronal disorders.

METHODS

A VE-deficient mouse model was prepared by feeding the animals a diet lacking VE. In addition, to evaluate the effect of VE-containing rice bran (RB) on VE deficiency, a diet including RB was also provided. VE levels in the brain tissue, as well as in the RB, were measured using an HPLC system. Behavioral tests, including rotarod, wheel running activity, Y-maze, and elevated plus maze were performed. To clarify the effect of VE deficiency and RB, we investigated the induction of heme oxygenase-1 (HO-1). Histological studies were performed using HE staining and immunohistochemical studies were performed using antibodies against glial fibrillary acidic protein (GFAP) and ionized calcium binding adaptor molecule 1 (Iba1).

RESULTS

VE in the mouse brain under a VE-deficient diet was decreased, and recovered α-tocopherol levels were observed in the brain of mice fed an RB diet. Motor behavioral scores were decreased in VE-deficient conditions, while the supplementation of RB improved motor function. HO-1, a marker of oxidative stress, was upregulated in the mouse brain under VE deficiency, however, RB supplementation inhibited the increase of HO-1. Histological analyses showed neuronal degeneration of Purkinje cells and decreased GFAP-immunoreactivity of Bergmann glia in the cerebellum. In addition, activated astrocytes and microglia were observed in mice fed the VE-deficient diet. Mice fed the RB diet showed improvement in these histological abnormalities.

CONCLUSION

A VE-deficient diet induced motor dysfunction in mice due to the degeneration of Purkinje cells in the cerebellum. Oral supplementation of RB increases VE in the brain and improved the motor dysfunction caused by VE deficiency. Thus, RB or unpolished rice may be a promising VE supplement.

Allele-specific regulation of mutant Huntingtin by Wig1, a downstream target of p53

p53 has been implicated in the pathophysiology of Huntington's disease (HD). Nonetheless, the molecular mechanism of how p53 may play a unique role in the pathology remains elusive. To address this question at the molecular and cellular biology levels, we initially screened differentially expressed molecules specifically dependent on p53 in a HD animal model. Among the candidate molecules, wild-type p53-induced gene 1 (Wig1) is markedly upregulated in the cerebral cortex of HD patients. Wig1 preferentially upregulates the level of mutant Huntingtin (Htt) compared with wild-type Htt. This allele-specific characteristic of Wig1 is likely to be explained by higher affinity binding to mutant Htt transcripts than normal counterpart for the stabilization. Knockdown of Wig1 level significantly ameliorates mutant Htt-elicited cytotoxicity and aggregate formation. Together, we propose that Wig1, a key p53 downstream molecule in HD condition, play an important role in stabilizing mutant Htt mRNA and thereby accelerating HD pathology in the mHtt-p53-Wig1 positive feedback manner.

Depletion of p62 reduces nuclear inclusions and paradoxically ameliorates disease phenotypes in Huntington's model mice

Huntington's disease (HD) is a dominantly inherited genetic disease caused by mutant huntingtin (htt) protein with expanded polyglutamine (polyQ) tracts. A neuropathological hallmark of HD is the presence of neuronal inclusions of mutant htt. p62 is an important regulatory protein in selective autophagy, a process by which aggregated proteins are degraded, and it is associated with several neurodegenerative disorders including HD. Here, we investigated the effect of p62 depletion in three HD model mice: R6/2, HD190QG and HD120QG mice. We found that loss of p62 in these models led to longer life spans and reduced nuclear inclusions, although cytoplasmic inclusions increased with polyQ length. In mouse embryonic fibroblasts (MEFs) with or without p62, mutant htt with a nuclear localization signal (NLS) showed no difference in nuclear inclusion between the two MEF types. In the case of mutant htt without NLS, however, p62 depletion increased cytoplasmic inclusions. Furthermore, to examine the effect of impaired autophagy in HD model mice, we crossed R6/2 mice with Atg5 conditional knockout mice. These mice also showed decreased nuclear inclusions and increased cytoplasmic inclusions, similar to HD mice lacking p62. These data suggest that the genetic ablation of p62 in HD model mice enhances cytoplasmic inclusion formation by interrupting autophagic clearance of polyQ inclusions. This reduces polyQ nuclear influx and paradoxically ameliorates disease phenotypes by decreasing toxic nuclear inclusions.

Dopamine-mediated oxidation of methionine 127 in α-synuclein causes cytotoxicity and oligomerization of α-synuclein

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the selective loss of dopaminergic neurons and the presence of Lewy bodies. Many recent studies focused on the interaction between α-synuclein (α-syn) and dopamine in the pathogenesis of PD, and fluorescent anisotropy suggested that the C-terminal region of α-syn may be a target for modification by dopamine. However, it is not well understood why PD-related pathogenesis occurs selectively in dopaminergic neurons. We investigated the interaction between dopamine and α-syn with regard to cytotoxicity. A soluble oligomer was formed by co-incubating α-syn and dopamine in vitro. To clarify the effect of dopamine on α-syn in cells, we generated PC12 cells expressing human α-syn, as well as the α-syn mutants, M116A, Y125D, M127A, S129A, and M116A/M127A, in a tetracycline-inducible manner (PC12-TetOFF-α-syn). Overexpression of wildtype α-syn in catecholaminergic PC12 cells decreased cell viability in long-term cultures, while a competitive inhibitor of tyrosine hydroxylase blocked this vulnerability, suggesting that α-syn-related cytotoxicity is associated with dopamine metabolism. The vulnerabilities of all mutant cell lines were lower than that of wildtype α-syn-expressing cells. Moreover, α-syn containing dopamine-mediated oxidized methionine (Met(O)) was detected in PC12-TetOFF-α-syn. Met(O) was lower in methionine mutant cells, especially in the M127A or M116A/M127A mutants, but also in the Y125D and S129A mutants. Co-incubation of dopamine and the ₁₂₅YEMPS₁₂₉ peptide enhanced the production of H₂O₂, which may oxidize methionine residues and convert them to Met(O). Y125- or S129-lacking peptides did not enhance the dopamine-related production of H₂O₂. Our results suggest that M127 is the major target for oxidative modification by dopamine, and that Y125 and S129 may act as enhancers of this modification. These results may describe a mechanism of dopaminergic neuron-specific toxicity of α-syn in the pathogenesis of PD.

Leber's Hereditary Optic Neuropathy with Olivocerebellar Degeneration due to G11778A and T3394C Mutations in the Mitochondrial DNA

Background

Leber's hereditary optic neuropathy (LHON) is a mitochondrial disorder with optic nerve atrophy. Although there are no other associated neurological abnormalities in most cases of LHON, cases of "LHON plus" have been reported.

Case Report

The proband was a 37-year-old man who had visual and gait disturbances that had first appeared at 10 years of age. He showed horizontal gaze palsy, gaze-evoked nystagmus, dysarthria, and cerebellar ataxia. Brain and orbit MRI disclosed atrophy of the optic nerve and cerebellum, and degenerative changes in the bilateral inferior olivary nucleus. Mutational analyses of mitochondrial DNA identified the coexistence of heteroplasmic G11778A and homoplasmic T3394C mutations.

Conclusions

These results suggest that the combination of G11778A and T3394C mutations leads to an atypical LHON phenotype.

Cytoprotective effect of chlorogenic acid against α-synuclein-related toxicity in catecholaminergic PC12 cells

Parkinson’s disease is a major neurodegenerative disease involving the selective degeneration of dopaminergic neurons and α-synuclein containing Lewy bodies formation in the substantia nigra. Although α-synuclein is a key molecule for both dopaminergic neuron death and the formation of inclusion bodies, the mechanism of α-synuclein induction of Parkinson’s disease-related pathogenesis is not understood. In the present study, we found that the interaction between dopamine and α-synuclein requires the oxidation of dopamine. Furthermore, we examined the protective effect of chlorogenic acid, a major polyphenol contained in coffee, against α-syn and dopamine-related toxicity. Chlorogenic acid inhibits several DA/α-synuclein-related phenomenon, including the oxidation of dopamine, the interaction of oxidized dopamine with α-synuclein, and the oligomerization of α-synuclein under dopamine existing conditions in vitro. Finally, we showed that the cytoprotective effect against α-synuclein-related toxicity in PC12 cells that can be controlled by the Tet-Off system. Although the induction of α-synuclein in catecholaminergic PC12 cells causes a decrease in cell viability, chlorogenic acid rescued this cytotoxicity significantly in a dose dependent manner. These results suggest that the interaction of oxidized DA with α-synuclein may be a novel therapeutic target for Parkinson’s disease, and polyphenols, including chlorogenic acid, are candidates as protective and preventive agents for Parkinson’s disease onset.

Mechanisms underlying production and externalization of oxidized phosphatidylserine in apoptosis: involvement of mitochondria

The present study was performed by using selective inhibitors of caspase-8 and caspase-3 functioning upstream and downstream from mitochondria, respectively to determine whether mitochondria are involved in the mechanisms underlying production and externalization of oxidized phosphatidylserine (PSox) during Fas-mediated apoptosis. Treatment with anti-Fas antibody induced caspase-3 activation, chromatin condensation, release of cytochrome c (cyt c) from mitochondria into the cytosol as well as production of PSox and its exposure to the cell surface in Jurkat cells. Inhibition of caspase-8 by pretreatment with Z-IETD-FMK, a membrane permeable selective caspase-8 inhibitor reduced mitochondrial cyt c release, the amount of PSox not only within but also on the surface of Jurkat cells, caspase-3 activation, and apoptotic cell number after treatment with anti-Fas antibody. In contrast, Z-DEVD-FMK, a membrane permeable selective caspase-3 inhibitor was unable to inhibit cyt c release, and the amount of PSox both within and on the surface of the cells after anti-Fas antibody, although it suppressed caspase-3 activation and apoptosis. Thus, these results strongly suggest that mitochondria play an important role in production of PSox and subsequent its externalization during apoptosis.

Parkin controls dopamine utilization in human midbrain dopaminergic neurons derived from induced pluripotent stem cells

Parkinson's disease (PD) is defined by the degeneration of nigral dopaminergic (DA) neurons and can be caused by monogenic mutations of genes such as parkin. The lack of phenotype in parkin knockout mice suggests that human nigral DA neurons have unique vulnerabilities. Here we generate induced pluripotent stem cells from normal subjects and PD patients with parkin mutations. We demonstrate that loss of parkin in human midbrain DA neurons greatly increases the transcription of monoamine oxidases and oxidative stress, significantly reduces DA uptake and increases spontaneous DA release. Lentiviral expression of parkin, but not its PD-linked mutant, rescues these phenotypes. The results suggest that parkin controls dopamine utilization in human midbrain DA neurons by enhancing the precision of DA neurotransmission and suppressing dopamine oxidation. Thus, the study provides novel targets and a physiologically relevant screening platform for disease-modifying therapies of PD.

Parkin degrades estrogen-related receptors to limit the expression of monoamine oxidases

Parkin, whose mutations cause Parkinson disease (PD), controls oxidative stress by limiting the expression of monoamine oxidases (MAO)--mitochondrial enzymes responsible for the oxidative de-amination of dopamine. Here, we show that parkin performed this function by increasing the ubiquitination and degradation of estrogen-related receptors (ERR), orphan nuclear receptors that play critical roles in the transcription regulation of many nuclear-encoded mitochondrial proteins. All three ERRs (α, β and γ) increased the transcription of MAOs A and B; the effects were abolished by parkin, but not by its PD-linked mutants. Parkin bound to ERRs and increased their ubiquitination and degradation. In fibroblasts from PD patients with parkin mutations or brain slices from parkin knockout mice, degradation of ERRs was significantly attenuated. The results reveal the molecular mechanism by which parkin suppresses the transcription of MAOs to control oxidative stress induced by dopamine oxidation.

Parkin protects dopaminergic neurons against microtubule-depolymerizing toxins by attenuating microtubule-associated protein kinase activation

Mitogen-activated protein kinases, originally known as microtubule-associated protein (MAP) kinases, are activated in response to a variety of stimuli. Here we report that microtubule-depolymerizing agents such as colchicine or nocodazole induced strong activation of MAP kinases including JNK, ERK, and p38. This effect was markedly attenuated by parkin, whose mutations are linked to Parkinson disease (PD). Our previous study has shown that parkin stabilizes microtubules through strong interactions mediated by three independent domains. We found that each of the three microtubule-binding domains of parkin was sufficient to reduce MAP kinase activation induced by microtubule depolymerization. The ability to attenuate microtubule depolymerization and the ensuing MAP kinase activation was abrogated in B-lymphocytes and fibroblasts derived from PD patients with parkin mutations such as exon 4 deletion. Such mutations produced truncated parkin proteins lacking any microtubule binding domain and prevented parkin from protecting midbrain dopaminergic neurons against microtubule-depolymerizing toxins such as rotenone or colchicine. Consistent with these, blocking MAP kinase activation in midbrain dopaminergic neurons by knocking down MAP kinase kinases (MKK) significantly reduced the selective toxicity of rotenone or colchicine. Conversely, overexpression of MAP kinases caused marked toxicities that were significantly attenuated by parkin. Thus, the results suggest that parkin protects midbrain dopaminergic neurons against microtubule-depolymerizing PD toxins such as rotenone by stabilizing microtubules to attenuate MAP kinase activation.

Assessment of hallucinations in Parkinson's disease using a novel scale

OBJECTIVE

To assess hallucinations in Parkinson's disease (PD), we developed a novel practical rating scale that evaluates five items including variety, frequency, and severity of hallucinations, caregiver burden levels, and psychiatric status at nighttime.

METHODS

Forty-one PD patients and their caregivers were examined regarding the status of the hallucinations associated with PD.

RESULTS

As a measure of internal consistency, the Tottori University Hallucination Rating Scale (TUHARS) has a Cronbach's alpha of 0.88. Mini-Mental State Examination (MMSE) and Hoehn-Yahr stage were associated with the TUHARS scores in a multivariate regression analysis. Visual hallucinations are the most common. However, half of the patients who reported visual hallucinations also had other hallucinations. The scale scores in the PD patients with dementia (PDD) group were significantly greater than in the PD patients without dementia (PDnD) group.

CONCLUSIONS

TUHARS appears to be a suitable and easily administered instrument for assessment of hallucinations in PD. PD patients experienced various kinds of hallucinations. Hallucinations may have a close relationship with cognitive decline in PD patients.

Homocysteine is toxic for dopaminergic neurons in primary mesencephalic culture

Hyperhomocysteinemia associated with L-3,4-dihydroxyphenylalanine (L-dopa) treatment has been observed in patients with Parkinson's disease. We investigated the toxicity of homocysteine (Hcy) on E14-rat-primary mesencephalic culture. Exposure to 0-5 mM Hcy decreased number of tyrosine hydroxylase (TH)-positive dopaminergic neurons and microtubule associated protein 2 (MAP2)-positive neurons in a dose-dependent manner. TH-positive neurons had vulnerability to the insult of Hcy compared with the other MAP2-positive neurons. In dopaminergic neurons, 5 microM reserpine enhanced the Hcy toxicity, whereas 50 microM alpha-methyltyrosine attenuated the toxic effect, showing that the intracellular dopamine increased the cytotoxicity of Hcy. Hcy enhanced the toxicity of 1-methyl-4-phenylpyridinium (MPP+) for dopaminergic neurons. It was suggested that the Hcy toxicity was associated with the oxidative stress. Hcy is toxic for dopaminergic neurons, and hyperhomocysteinemia may modify the clinical course of Parkinson's disease.

Clinical evaluation of Parkinson's disease dementia: association with aging and visual hallucination

OBJECTIVES

In order to explore factors associated with the development of dementia in Parkinson's disease (PD) and Dementia with Lewy bodies (DLB), we systematically investigated the clinical evaluation of PD and DLB patients hospitalized in the Department of Neurology at Tottori University Hospital, Japan.

RESULTS

There were 208 patients diagnosed as having PD and 39 patients diagnosed with DLB in this study. Of the patients with PD, 67 (32%) developed dementia and only five PD+ patients were considered to have cognitive impairment attributable to Alzheimer's disease (AD) or vascular dementia (VaD). Fifty-four (81%) PDD patients had visual hallucinations (VH) with or without cognitive fluctuation. The onset age of parkinsonian motor symptoms of patients with PD dementia (PDD) did not differ from that of PD patients without dementia. There was a significant inverse correlation between the onset age of motor symptoms in PD and the onset of their dementia in PDD. Seventy-five (36%) patients with PD had experienced VH and most of the PDD patients had experienced VH within 1 year before or after diagnosis of PDD.

CONCLUSIONS

These results indicate that aging and VH are important factors associated with dementia in PD.

Diagnostic markers for diagnosing dementia with Lewy bodies: CSF and MIBG cardiac scintigraphy study

OBJECTIVE

This study examined the diagnostic value of cerebrospinal fluid (CSF) markers and iodine-123 metaiodobenzylguanidine ((123)I-MIBG) cardiac scintigraphy in distinguishing dementia with Lewy bodies (DLB) from Alzheimer's disease (AD).

METHODS

CSF levels of amyloid beta1-42 (Abeta42) and 181-Thr phosphorylated tau (p-tau) were measured using enzyme linked immunosorbent assay (ELISA) kits. (123)I-MIBG cardiac scintigraphy was performed in patients with AD and DLB, and control (CTL) subjects.

RESULTS

Increased CSF levels of p-tau in AD were found compared to DLB patients and CTL subjects (P<0.01), but there was no significant difference in CSF levels of Abeta42 between AD and DLB patients. The early and delayed heart to mediastinum (H/M) ratios of (123)I-MIBG cardiac scintigraphy were significantly decreased in patients with DLB compared to AD patients and CTL subjects (P<0.01). The receiver operating characteristic (ROC) analysis revealed that the diagnostic value of (123)I-MIBG cardiac scintigraphy was superior to that of CSF markers.

CONCLUSIONS

(123)I-MIBG cardiac scintigraphy may be useful for discriminating between DLB and AD.

Serum proteomic profiling of dementia with Lewy bodies: diagnostic potential of SELDI-TOF MS analysis

Dementia with Lewy bodies (DLB) is the second most common senile degenerative dementia after Alzheimer's disease (AD). The presentation of overlapping symptoms between these two disorders leads to difficulties in the determination of clinical entities. Serum samples were subjected to surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) analysis in order to identify a diagnostic marker for DLB. Four putative protein peaks (m/z 3,883, 4,964, 7,761 and 10,534) were differentially expressed in DLB patients compared to AD patients and control subjects. Receiver operating characteristics (ROC) analysis of a multivariate logistic model of the combination of three peaks (m/z 3,883, 7,761 and 10,534) exhibited the highest discriminatory ability of DLB subjects from non-DLB subjects with a sensitivity of 83.3%, a specificity of 95.8%, a positive predictive value of 90.9% and a negative predictive value of 92.0%. SELDI-TOF MS profiling, therefore, has revealed a serum signature with high diagnostic potential for DLB.

Parkin mediates neuroprotection through activation of IkappaB kinase/nuclear factor-kappaB signaling

Mutations in the parkin gene are a major cause of autosomal recessive Parkinson's disease. Here we show that the E3 ubiquitin ligase parkin activates signaling through the IkappaB kinase (IKK)/nuclear factor kappaB (NF-kappaB) pathway. Our analysis revealed that activation of this signaling cascade is causally linked to the neuroprotective potential of parkin. Inhibition of NF-kappaB activation by an IkappaB super-repressor or a kinase-inactive IKKbeta interferes with the neuroprotective activity of parkin. Furthermore, pathogenic parkin mutants with an impaired neuroprotective capacity show a reduced ability to stimulate NF-kappaB-dependent transcription. Finally, we present evidence that parkin interacts with and promotes degradation-independent ubiquitylation of IKKgamma/NEMO (NF-kappaB essential modifier) and TRAF2 [TNF (tumor necrosis factor) receptor-associated factor 2], two critical components of the NF-kappaB pathway. Thus, our results support a direct link between the neuroprotective activity of parkin and ubiquitin signaling in the IKK/NF-kappaB pathway.

Epidemiology of Epstein-Barr virus, cytomegalovirus, and Kaposi's sarcoma-associated herpesvirus infections in peripheral blood leukocytes revealed by a multiplex PCR assay

A multiplex polymerase chain reaction (PCR) has been developed for the simultaneous detection of Epstein-Barr virus (EBV), cytomegalovirus (CMV), and Kaposi's sarcoma-associated herpesvirus (KSHV) in a clinical sample. Primers of multiplex PCR were designed to amplify specific regions of the EBV EBNA1, CMV IE2, and KSHV LANA genes. This multiplex PCR assay was found to have detection sensitivities of 1-10 copies of purified viral DNA cloned into the plasmid. To assess diagnostic and pre-clinical applications with this method, we utilized KSHV-positive primary effusion lymphoma (PEL) cells, EBV-positive Burkitt's lymphoma cells, CMV-infected fibroblast cells, and clinically prepared peripheral blood leukocytes (PBLs) that had been infected with viruses. We found that this multiplex PCR assay has high sensitivity and specificity for simultaneous detection of EBV, CMV, and KSHV genomes in a single amplification from a clinical material. Using this multiplex PCR assay, we investigated the prevalence of EBV, CMV, and KSHV in PBL samples from normal Japanese randomly selected. KSHV, EBV, and CMV genomes were detected in samples from 2 (0.2%), 377 (39.5%), and 27 (2.8%) of the 953 blood donors, respectively. Interestingly, both EBV and CMV genomes were detected in samples from all KSHV-positive donors.

Increased plasma substance P and CGRP levels, and high ACE activity in migraineurs during headache-free periods

Substance P (SP), calcitonin gene-related peptide (CGRP), and angiotensin converting enzyme (ACE) may have roles in trigeminovascular nociceptive mechanisms. We investigated interictal levels of SP, CGRP, ACE activity, and their correlation, in a sample of migraineurs. Forty-one patients suffering from migraine with aura (MA), 54 without aura (MO), and 52 non-headache subjects (controls) participated in this study. Blood samples were collected from cubital veins. Plasma levels of SP and CGRP were measured by enzyme immunoassay. Plasma ACE activities were measured spectrophotometrically. SP levels in MA (6.6+/-3.7 pg/ml; mean+/-SD) and MO (6.6+/-3.2 pg/ml) were significantly higher than in controls (4.8+/-2.4 pg/ml) (P<0.01). CGRP levels in MA (18.8+/-8.8 pg/ml) and MO (19.1+/-9.4 pg/ml) were also significantly higher than in controls (13.4+/-4.4 pg/ml) (P<0.01). ACE activities in MA (34.6+/-19.0 U/l) were significantly higher than in MO (25.3+/-13.2 U/l) and controls (27.0+/-20.4 U/l) (P<0.05). There was a significant correlation between SP and CGRP levels (P<0.05). In MA, SP and CGRP showed a tendency toward positive correlation, which was not significant. There was a weak, but significant positive correlation between SP levels and ACE activities (P<0.01). However, a relationship between ACE activities and CGRP levels was not observed. The data suggest that SP, CGRP, and ACE are relevant to migraine pathophysiology, and that they may interact.

Detection of compound heterozygous deletions in the parkin gene of fibroblasts in patients with autosomal recessive hereditary parkinsonism (PARK2)

Mutations in the parkin gene are a common cause of autosomal recessive, juvenile or early onset parkinsonism (PARK2). In this report, we use RT-PCR to detect compound heterozygous deletions of the parkin gene in fibroblasts from two cases of middle age-onset familial parkinsonism with lower extremities-dominant resting tremor and mild cogwheel rigidity. Although exonic amplification of the parkin gene showed a deletional mutation of exon 3-4, their family histories suggested that the deletional mutations were a compound heterozygous abnormality of discrete origin. Immunoblotting demonstrated that abundant Parkin protein was expressed in fibroblasts, but little expression was detected in lymphocytes. RT-PCR using RNA isolated from the patients' fibroblasts indicated a parkin mutation in this family that consisted of compound heterozygous deletions (del exon3-4/del exon3-5). These results suggest that RT-PCR using the patients' fibroblasts may be helpful for the detection of compound heterozygous abnormalities in the parkin gene.

Increased plasma transforming growth factor-beta1 in migraine

BACKGROUND AND OBJECTIVES

Migraine is characterized by the peripheral and central sensitization of pain perceptive neural systems, and neurogenic inflammation is a key step in the development of migraine headache. We focused on transforming growth factor-beta1 (TGF-beta1), which is a multifunctional proinflammatory cytokine. To address the possibility of TGF-beta1 involvement in migraine, we investigated the plasma level of TGF-beta1 in patients with migraine headache during headache-free periods.

SUBJECTS AND METHODS

Sixty-eight subjects with migraine participated: 23 with migraine with aura (MWA) and 45 without aura (MWoA). We recruited 58 healthy subjects without headache as controls. In addition, we examined 12 subjects with episodic tension-type headache. Platelet poor plasma (PPP) was obtained from subjects during headache free-periods. TGF-beta1 levels in PPP were determined by enzyme-linked immunosorbent assay.

RESULTS

The TGF-beta1 level in PPP was 2.62*+/- 0.23 (mean +/- SE) ng/mL in migraine, 2.08 +/- 0.20 ng/mL in tension-type headache, and 1.80 +/- 0.09 ng/mL in controls (P= .007, ANOVA; *P < .01, post hoc tests vs. the controls).

CONCLUSION

TGF-beta1 in PPP was significantly increased in patients with migraine during headache-free periods. TGF-beta1 may play some role in the development of migraine headache.

[Anti-Yo antibody associated paraneoplastic cerebellar degeneration with gastric adenocarcinoma in a male patient: a case report]

We report a 71-year-old man presenting with paraneoplastic cerebellar degeneration (PCD) associated anti-Yo antibody after surgery for gastric adenocarcinoma. Seven months after partial gastrectomy, he deviated to the right on walking. Furthermore, a feeling of dysarthria appeared and he was unable to sit after 2 months. When he was hospitalized, he showed a disturbance of his eye movement on lower gaze, a nystagmus on lateral gaze, saccadic eye movement on smooth pursuit, cerebellar ataxia, and decreasing of muscle tonus in his extremities. However, no atrophic findings of the brainstem and cerebellum were revealed by brain MRI. He responded poorly to treatment with high-dose methylprednisolone, high-dose immunoglobulin, double filtration plasmapheresis and rehabilitation. There was a strong anti-Yo immunohistochemical staining of the cytoplasm in both the patient's tumor cells and normal cerebellar Purkinje cells. These findings suggest that PCD associated with anti-Yo antibody triggered by adenocarcinoma might occur in this male patient.

D-β-hydroxybutyrate protects dopaminergic SH-SY5Y cells in a rotenone model of Parkinson's disease

It has been postulated that the pathogenesis of Parkinson's disease (PD) is associated with mitochondrial dysfunction. Rotenone, an inhibitor of mitochondrial complex I, provides models of PD both in vivo and in vitro. We investigated the neuroprotective effect of D-beta-hydroxybutyrate (bHB), a ketone body, against rotenone toxicity by using SH-SY5Y dopaminergic neuroblastoma cells. SH-SY5Y cells, differentiated by all-trans-retinoic acid, were exposed to rotenone at concentrations ranging from 0 to 1,000 nM. We evaluated cellular oxidation reduction by the alamarBlue assay, viability by lactate dehydrogenase (LDH) assay, and survival/death ratio by live/dead assays. Exposure to rotenone for 48 hr oxidized cells and decreased their viability and survival rate in a concentration-dependent manner. Pretreatment of cells with 8 mM bHB provided significant protection to SH-SY5Y cells. Whereas rotenone caused the loss of mitochondrial membrane potential, released cytochrome c into the cytosol, and reduced cytochrome c content in mitochondria, addition of bHB blocked this toxic effect. bHB also attenuated the rotenone-induced activation of caspase-9 and caspase-3. Administration of 0-10 mM 3-nitropropionic acid, a complex II inhibitor, also decreased the reducing power of SH-SY5Y cells measured by alamarBlue assay. Pretreatment with 8 mM bHB attenuated the decrease of alamarBlue fluorescence. These data demonstrated that bHB had a neuroprotective effect that supported the mitochondrial respiration system by reversing the inhibition of complex I or II. Ketone bodies, the alternative energy source in the mammalian brain, appear to have therapeutic potential in PD.

Novel cytoprotective mechanism of anti-parkinsonian drug deprenyl: PI3K and Nrf2-derived induction of antioxidative proteins

Neuroprotection has received considerable attention as a strategy for the treatment of Parkinson's disease (PD). Deprenyl (Selegiline) is a promising candidate for neuroprotection; however, its cytoprotective mechanism has not been fully clarified. Here, we report a novel cytoprotective mechanism of deprenyl involving PI3K and Nrf2-mediated induction of oxidative stress-related proteins. Deprenyl increased the expression of HO-1, PrxI, TrxI, TrxRxI, gammaGCS, and p62/A170 in SH-SY5Y cells. Deprenyl also induced the nuclear accumulation of Nrf2 and increased the binding activity of Nrf2 to the enhancer region of human genomic HO-1. The Nrf2-mediated induction of antioxidative molecules was controlled by PI3K. Indeed, furthermore, neurotrophin receptor TrkB was identified as an upstream signal for PI3K-Nrf2 activation by deprenyl. These results suggest that the cytoprotective effect of deprenyl is, in part, dependent on Nrf2-mediated induction of antioxidative proteins, suggesting that activation of the PI3K-Nrf2 system may be a useful therapeutic strategy for PD.

Multiplex PCR-based DNA array for simultaneous detection of three human herpesviruses, EVB, CMV and KSHV

Human lymphotropic herpesviruses, Epstein-Barr virus (EBV), cytomegalovirus (CMV) and Kaposi's sarcoma-associated herpesvirus (KSHV) are responsible for a wide variety of human diseases. Due to an increase in diseased states associated with immunosuppression, more instances of co-morbid infections with these herpesviruses have resulted in viral reactivations that have caused numerous fatalities. Therefore, the development of rapid and accurate method to detect these viruses in immunocompromised patients is vital for immediate treatment with antiviral prophylactic drugs. In this study, we developed a new multiplex PCR method coupled to DNA array hybridization, which can simultaneously detect all three human herpesviruses in one single cell sample. Multiplex PCR primers were designed to amplify specific regions of the EBV (EBER1), CMV (IE) and KSHV (LANA) viral genomes. Pre-clinical application of this method revealed that this approach is capable of detecting as few as 1 copy of the viral genomes for KSHV and CMV and 100 copies of the genome for EBV. Furthermore, this highly sensitive test showed no cross-reactivity among the three viruses and is capable of detecting both KSHV and EBV viral genomes simultaneously in the lymphoblastoid cells that have been double infected with both viruses. Thus, this array-based approach serves as a rapid and reliable diagnostic tool for clinical applications.

Peroxiredoxin I expression in tongue squamous cell carcinomas as involved in tumor recurrence

Peroxiredoxin (Prx) I is an antioxidant protein expressed in proliferating cells. We investigated Prx I as marker for tongue cancer status by correlating clinical features with Prx I expression. Samples from 132 patients with squamous cell carcinoma in the tongue were examined by immunohistochemistry with an anti-Prx I antibody. Correlations between Prx I expression and the clinical features of tumors were statistically determined using univariate and multivariate analyses. Univariate analysis showed Prx I was significantly associated with local recurrence (P=0.033). By multiple logistic regression analysis, Prx I expression was associated with local recurrence (odds ratio: 2.84; 95% confidence interval: 1.09-7.43; P=0.034) and lymph node recurrence (odds ratio: 2.86; 95% confidence interval: 1.02-8.01; P=0.046). Our results suggested that Prx I expression indicates tumors with a high potential for recurrence. Prx I may be used clinically to guide treatment for squamous cell carcinoma of the tongue.

Association of the insertion/deletion polymorphism of the angiotensin I-converting enzyme gene in patients of migraine with aura

Recently, several angiotensin I-converting enzyme (ACE) inhibitors and an angiotensin II receptor blocker were demonstrated to have a clinically important prophylactic effect in migraine. ACE is one of the key enzymes in the rennin-angiotensin-aldosterone system, which modulates vascular tension and blood pressure. In humans, serum ACE levels are strongly genetically determined. Individuals who were homozygous for the deletion (D) allele showed increased ACE activity levels. To investigate the role of ACE polymorphism in headache, we analyzed the ACE insertion (I)/deletion (D) genotypes of 54 patients suffering from migraine with aura (MwA), 122 from migraine without aura, 78 from tension-type headache (TH), and 248 non-headache healthy controls. The ACE D allele were significantly more frequent in the MwA than controls (p<0.01). The incidence of the D/D genotype in MwA (25.9%) was significantly higher than that in controls (12.5%; p<0.01; odds ratio=5.26, 95% confidence interval: 1.69-16.34, adjusted for age and gender). No differences in the remaining groups were found. Our results support the conclusion that the D allele and the D/D genotype in the ACE gene is a genetic risk factor for Japanese MwA. There seems to be a possible relationship between ACE activity and the pathogenesis of migraine.

L-dopa and dopamine enhance the formation of aggregates under proteasome inhibition in PC12 cells

The formation of inclusion bodies in dopaminergic neurons is associated with the pathogenesis of Parkinson's disease. In order to clarify the role of dopamine/L-dopa in the formation of protein aggregates, we investigated dopamine/L-dopa-related aggregation using an experimental inclusion model. The inhibition of tyrosine hydroxylase (TH) by alpha-methyltyrosine dramatically decreased MG132-induced aggregate formation. In addition, the inhibition of TH caused the upregulation of proteasomes in cultured cells and the dopamine/L-dopa induced non-enzymatic polymerization of ubiquitin. This inhibition did not affect cell viability. These results suggest that dopamine/L-dopa might enhance aggregate formation, and that intracellular aggregates may not be toxic to cells.

Huntington's Disease-like 2 (HDL2) in North America and Japan

Huntington's Disease-like 2 (HDL2) is a progressive, autosomal dominant, neurodegenerative disorder with marked clinical and pathological similarities to Huntington's disease (HD). The causal mutation is a CTG/CAG expansion mutation on chromosome 16q24.3, in a variably spliced exon of junctophilin-3. The frequency of HDL2 was determined in nine independent series of patients referred for HD testing or selected for the presence of an HD-like phenotype in North America or Japan. The repeat length, ancestry, and age of onset of all North American HDL2 cases were determined. The results show that HDL2 is very rare, with a frequency of 0 to 15% among patients in the nine case series with an HD-like presentation who do not have the HD mutation. HDL2 is predominantly, and perhaps exclusively, found in individuals of African ancestry. Repeat expansions ranged from 44 to 57 triplets, with length instability in maternal transmission detected in a repeat of r2=0.29, p=0.0098). The results further support the evidence that the repeat expansion at the chromosome 16q24.3 locus is the direct cause of HDL2 and provide preliminary guidelines for the genetic testing of patients with an HD-like phenotype.

A haplotype of the methylenetetrahydrofolate reductase gene is protective against late-onset Alzheimer's disease

Epidemiological studies have shown that elevated plasma homocysteine (Hcy) levels play an important role in the pathogenesis of Alzheimer's disease (AD). In spite of the evidence that a C677T polymorphism in the methylenetetrahydrofolate reductase (MTHFR) gene elevates plasma Hcy levels, the impact of the C677T polymorphism on the development of AD is controversial. Here, we performed a genetic case-control study in a Japanese population to investigate whether three polymorphisms of the MTHFR gene, C677T (Ala222Val), A1298C (Glu429Ala), and A1793G (Arg594Gln), are associated with the development of late-onset AD (LOAD). In our study, the MTHFR gene had four major regional haplotypes: Haplotype A (677C-1298A-1793G), Haplotype B (677T-1298A-1793G), Haplotype C (677C-1298C-1793G), and Haplotype D (677C-1298C-1793A). The frequency of Haplotype C in LOAD was significantly lower than that in control group. Furthermore, the benefit conferred by the presence of at least one Haplotype C was stronger in LOAD patients who lacked the ApoE 4 allele (OR=0.293; 95% CI=0.115-0.744; P=0.010). The results indicate that Haplotype C of the MTHFR gene is protective against the development of LOAD.

[A case of malignant fibrous histiocytoma with metastatic brain tumors after tumorgenic embolism]

A 61-year-old man had been treated for malignant fibrous histiocytoma with the pulmonary and the lymph node metastasis in the department of orthopedics in our hospital. He was admitted to our department because of an acute onset of conscious disturbance and non-fluent aphasia. Diffusion-weighted imaging (DWI) showed high signal intensity areas in the bilateral cerebella, thalami and posterior lobes. T2WI did not show any mass effects. Enhanced CT did not reveal any enhanced lesion. He was diagnosed as having cerebral embolism, and his conscious disturbance was improved after medication. Eight weeks later, he presented dysphagia, dysarthria, and ataxia in his extremities. DWI showed multiple lesions of low signal intensity located at the identical place where had showed high signal intensity in the initial DWI. T2WI showed high signal intensity area with mass effect. It was indicated that cerebral metastasis might grow after tumorgenic embolism. This is a rare case that tumor emboluses were developed to the metastatic brain tumors.

Transcriptional activation of p62/A170/ZIP during the formation of the aggregates: possible mechanisms and the role in Lewy body formation in Parkinson's disease

Formation of intracellular inclusion bodies due to defects in the protein degradation machinery is associated with the pathogenesis of neurodegenerative diseases. Sequestosomal protein p62/A170/ZIP, which is an oxidative stress-related protein and a ubiquitin-binding protein, is a component protein of Lewy bodies that are observed in patients with Parkinson's disease. The association of p62 with poly-ubiquitinated proteins may be an important step in the formation of intracellular protein aggregates like Lewy bodies. To study the role of p62 in the formation of protein aggregates in PC12 cells, we monitored the intracellular localizations of p62 and ubiquitinated proteins and the levels of both components during treatment with MG132, a proteasome inhibitor. In the early stage of aggregate formation, p62 did not always co-localize with ubiquitin. In contrast, these proteins were always co-localized in later stages. After the treatment of the cells with MG132, we found that the expression level of p62 increased due to the transcriptional activation of the gene and that higher molecular sizes of p62, corresponding to mono- and di-ubiquitinated formes, were also formed. Both the transcriptional inhibitor actinomycin D and an antisense oligonucleotide of p62 inhibited the MG132-mediated increase of p62, the sequestration of ubiquitinated proteins, and the enlargement of the aggregates. Furthermore, p62-positive aggregates were observed primarily in surviving cells. Together, these results suggest that p62 plays an important role in the protection of cells from the toxicity of misfolded proteins by enhancing aggregate formation especially in the later stages.

The regulatory region polymorphisms of the MTHFR gene are not associated with Alzheimer's disease

Recent epidemiological studies have emphasized the impact of elevated blood homocysteine levels on the pathogenesis of Alzheimer's disease (AD). In spite of a significant impact of a MTHFR C677T polymorphism on the blood homocysteine levels, the association between the C677T polymorphism and AD remains controversial. Therefore, other unidentified genetic factor(s) that regulate blood homocysteine levels may exist. Here, we have analyzed the 5'-upstream region of the MTHFR gene and examined AD patients (n = 223) and nondemented individuals (n = 323) for polymorphisms in the 5'-upstream region of the MTHFR gene. We identified two polymorphisms (-713G/A and -393C/A, upstream of the start codon). We found no significant relationship between AD and the 5'-upstream region polymorphisms of the MTHFR gene. Thus, our study does not reinforce the hypothesis of an independent involvement of the MTHFR gene upstream region polymorphisms in AD risk.

Expression of ubiquitin-binding protein p62 in ubiquitin-immunoreactive intraneuronal inclusions in amyotrophic lateral sclerosis with dementia: analysis of five autopsy cases with broad clinicopathological spectrum

Amyotrophic lateral sclerosis with dementia (ALSD), corresponding to the motor neuron disease type of frontotemporal dementia, is neuropathologically characterized by depletion of the motor neurons, degeneration of the extra-motor cerebral cortices and formation of ubiquitin-immunoreactive (not argyrophilic, tau-negative, alpha-synuclein-negative) intraneuronal inclusions. Recently, immunoreactivity for ubiquitin-binding protein p62 has been reported in several ubiquitin-containing intraneuronal or intraglial inclusions (e.g. neurofibrillary tangles, Pick bodies, Lewy bodies, glial cytoplasmic inclusions) in various neurodegenerative diseases. We examined p62 immunoreactivity in ubiquitin-immunoreactive intraneuronal inclusions in five ALSD cases with a broad clinicopathological spectrum. p62 immunoreactivity in ubiquitin-immunoreactive intraneuronal inclusions was seen in all cases. The mean proportion of p62-immunoreactive inclusions to the total number of ubiquitin-immunoreactive inclusions (p62/Ub ratio) in the dentate gyrus was 27.5 +/- 16.6% (range 6.3-47.3%). There was no correlation between p62/Ub ratio and the severity of dementia, duration of illness or neuropathological severity. Although the main constituent of these inclusions is unknown, our study suggests that p62 contributes to the formation of the inclusions via the same mechanism as in other previously reported neurodegenerative diseases. Since p62 is believed to have a neuroprotective role, the formation of these inclusions may represent a non-harmful, rather protective effect against the neuronal degeneration in ALSD.

Mutations of the MTHFR gene (428C>T and [458G>T+459C>T]) markedly decrease MTHFR enzyme activity

Methylenetetrahydrofolate reductase (MTHFR) is the only route for the synthesis of 5-methyltetrahydrofolate, which is utilized to convert homocysteine to methionine. In this study, we measured the enzyme activity of a mutant MTHFR that was detected in a patient with hyperhomocysteinemia. The 428C>T mutation in exon 2 of the MTHFR gene is a novel mutation, while the [458G>T+459C>T] mutation in exon 2 is a previously reported mutation. The activity of mutant enzymes containing the 428C>T, [458G>T+459C>T] and 677C>T mutations was 12.7+/-4.7%, 48.1+/-18.8%, and 43.6+/-14.4%, respectively, of that of the wild type enzyme. Our results suggest that these two variants each result in a severe MTHFR deficiency, which causes a developmental delay and cerebral vascular disease.

p53-mediated mitochondrial dysfunction by proteasome inhibition in dopaminergic SH-SY5Y cells

Decreased proteasome activity is an important pathology in Parkinson's disease (PD), which is related to cell death and Lewy body formation. In this study, we show that p53-activity may correlate with neuronal death via the mitochondrial pathway in PD model. The proteasome inhibitor, MG132, induced the accumulation of p53 in human dopaminergic neuroblastoma SH-SY5Y cells. The increased stabilization of p53 upregulated the level of Bax and mitochondrial depolarization. These events were inhibited by the p53 inhibitor, pifithrin-alpha (PFT). Cell viability analyzes demonstrated that PFT partially prevented MG132-induced cell death. These results suggest that p53 is a candidate as an intermediary between the proteasome system and mitochondria-related neuronal death in PD.

Heme oxygenase-1 expression predicts cervical lymph node metastasis of tongue squamous cell carcinomas

Heme oxygenase-1 (HO-1) is known as a stress-inducible protein. The present study was designed to investigate the relationship between HO-1 expression levels and clinical features of tongue cancer by using HO-1 responsiveness to stress as a clinical indicator. One-hundred and twelve biopsy samples from tongue squamous cell carcinomas were analyzed semiquantitatively by immunohistochemistry. Correlations between the expression level of HO-1 and the clinical features of tumors were statistically analyzed. Fifty-four cases with surgical confirmation of lymph node metastasis were examined for the association between cervical lymph node metastasis (pN) and other clinical features, including the HO-1 expression level, using logistic regression. The low HO-1 expression group contained significantly more undifferentiated samples (P=0.04) and pN positive cases (P=0.01) by univariate analysis. The low HO-1 expression group (odds ratio=8.49; 95% confidence interval=1.64-44.09, P=0.01) and an endophytic shape (odds ratio=16.79; 95% confidence interval=1.77-159.53, P=0.01) were significantly associated with an increased risk of developing lymph node metastasis by multivariate analysis. Low HO-1 expression was associated with lymph node metastasis. The expression profile suggests HO-1 could be used clinically as a marker for tumors possessing the potential for lymph node metastasis. This method could prove useful as an adjuvant method to detect lymph node metastasis and may help reduce the number of surgeries by indicating when surgery is unnecessary.