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Abstract: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is caused by mutations in human NOTCH3. We have recently reported that mutant Notch3 shows a greater propensity to form aggregates, and these aggregates resist degradation, leading to accumulation in the endoplasmic reticulum (ER). In this study, we searched for low-molecular compounds that decrease the amount of mutant Notch3 aggregates. Using a cell-based system, we found that degradation of preformed mutant aggregates was enhanced by treatment with either 4,5-dianilinophthalimide (DAPH) or staurosporine aglycone (SA), both of which inhibit amyloid β (Aβ) fibrillization. Regarding other low-molecular compounds interacting with Aβ fibrils, thioflavin T (ThT) also enhanced the clearance of mutant Notch3. These findings suggest that DAPH, SA, and ThT are potent reagents to dissociate the preformed aggregates of mutant Notch3 by disruption of intermolecular contacts of misfolded proteins. Our study may provide the basis for the development of a pharmacological therapy for CADASIL. [ABSTRACT FROM AUTHOR]

Presenilin 1 (PS1) forms the γ-secretase complex with at least three components: nicastrin, APH-1, and PEN-2. This complex mediates intramembrane cleavage of amyloid precursor protein (APP) to generate β-amyloid protein (Aβ) as well as other type 1 transmembrane proteins. Although PS1 mutations linked to familial Alzheimer's disease influence these cleavages, their biological consequences have not been fully understood. In this study, we used mRNA differential display analysis to identify a gene, denoted adoplin-1/ORMDL-1, which displays significantly reduced expression in association with PS1 mutations. Adoplin-1 and two highly homologous genes (adoplin-2,-3) constitute a gene family that encodes transmembrane proteins. The mRNA and protein levels of adoplins (particularly adoplin-1, -2) were markedly elevated in PS-deficient fibroblasts, compared to wild-type cells. Moreover, knockdown of the three adoplins by RNA interference affected maturation of nicastrin and its association with PS1. Adoplin knockdown additionally resulted in elevated levels of APP C-terminal fragments and decreased A[3 production, suggestive of reduced γ-secretase activity. Our data collectively indicate that adoplins are unique molecules with PS-related expression and functions that may play important role(s) in the maturation and activity of the γ-secretase complex. [ABSTRACT FROM AUTHOR]

Abstract: The Notch3 gene, a member of the Notch gene family, is expressed in a wide variety of tissues during development. We generated and analyzed Notch3-deficient mice to assess the in vivo role of the Notch3 gene. Consistent with previous observation of Krebs et al. [Characterization of Notch3-deficient mice: normal embryonic development and absence of genetic interactions with a Notch1 mutation, Genesis 37 (3) (2003) 139–143], the Notch3−/− mice were viable, fertile, and developed normally despite abundant expression of Notch3 in various embryonic tissues. We examined the details of Notch1, 2, and 4 expressions in the Notch3−/− embryos compared with those in wild-type embryos. As a result, we found that a deficiency in Notch3 did not affect the expression of Notch1, 2, and 4, and that either Notch1 or Notch2, or sometimes both, was always expressed in all Notch3-expressing tissues examined. These results support the idea that other Notch genes functionally compensate for Notch3 during embryonic development. We also surveyed the adult tissues of Notch3−/− mice and found significantly fewer thymocytes in 10-week-old mice. Therefore, the thymus might be a target tissue affected by Notch3 deficiency. [Copyright &y& Elsevier]

A new oral vaccine for Alzheimer's disease was developed using recombinant adeno-associated virus vector carrying Abeta cDNA (AAV/Abeta). Oral administration of the vaccine without adjuvant induced the expression and secretion of Abeta1-43 or Abeta1-21 in the epithelial cell layer of the intestine in amyloid precursor protein transgenic mice. Serum antibody levels were elevated for more than six months, while T cell proliferative responses to Abeta was not detected. Brain Abeta burden was significantly decreased compared to the control without inflammatory changes. This oral AAV/Abeta vaccine seems to be promising for prevention and treatment of Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Familial Alzheimer disease mutations of presenilin 1 (PS-1) enhance the generation of Aβ1-42, indicating that PS-1 is involved in amyloidogenesis. However, PS-1 transgenic mice have failed to show amyloid plaques in their brains. Because PS-1 mutations facilitate apoptotic neuronal death in vitro, we did careful quantitative studies in PS-1 transgenic mice and found that neurodegeneration was significantly accelerated in mice older than 13 months (aged mice) with familial Alzheimer disease mutant PS-1, without amyloid plaque formation. However, there were significantly more neurons containing intracellularly deposited Aβ42 in aged mutant transgenic mice. Our data indicate that the pathogenic role of the PS-1 mutation is upstream of the amyloid cascade. [ABSTRACT FROM AUTHOR]

The insulin-like growth factor II (rlGFll) is a mitogenic polypeptide, the expression of which is high in most rat tissues during embryonic development, yet is barely detectable in adult tissues except for some of neurogenic origin. The gene is present as a single copy in the genome but has three alternative leader exons, E1, E2 and E3, thereby with three independent transcriptional promoters. We analysed the expression of rIGFII and the relative efficiency of each promoter in hepatocarcinogen-treated livers, primary hepatomas and established hepatoma lines. The E3-specific product was first detected after 6 weeks of 3'-methyl-4-dimethylaminoazobenzene treatment and those of E1 and E2 also after 9 weeks. The levels gradually increased according to the sum of the treatment period, but reactivation was nil in the regenerating liver. Consistently high levels of expression were observed in all primary tumors, but the relative promoter activity varied with the tumor. The significance of rIGFII reactivation was discussed in the light of the hepatocarcinogenesis. [ABSTRACT FROM PUBLISHER]

In the pathogenesis of multiple sclerosis (MS), autoimmune T cells reactive with proteolipid protein (PLP) may play a crucial role. We determined 23 TCR (β-chain sequences of limiting dilution T cell lines (TCL) selected against a synthetic peptide, PLP 95–116, 105–124 or 139–155, from the peripheral blood of three Japanese MS patients with the DR2, w 15 haplotype (Tl, SK and OK). Fourteen sequences were originated from Tl, seven from SK and two from OK. The PLP-reactive TCL utilized various Vβ and Jβ; gene segments, but there was significant bias in the Vβ and Jβ usage. Overutilization of the Vβ2 family and dominant usage of the Jβ2.5 subfamily was seen in PLP 105–124-reactive and 95–116-reactive TCL respectively. More remarkably, a majority of the TCL were found to express β-chain CDR3 motifs that appear to be unique to MS brain infiltrates. In contrast, these motifs were only rarely seen in control TCR sequences from peripheral blood or from a TCL selected against tetanus toxoid. In several cases, the βCDR3 homologies between the PLP-reactive T cells and MS brain T cells were extensive, owing to the shared motifs in combination with the surrounding amino acid identities. These results indicate that PLP-specific T cells may be involved in the immunopathology of MS. [ABSTRACT FROM AUTHOR]

Abstract: Human E-selectin, an endothelial adhesion molecule, is induced in the brain arteries by cerebral ischemia and participates in the infiltration of leukocytes that cause inflammatory reaction leading to brain damage. To prevent leukocyte infiltration in the brain, we designed gene therapeutic constructs to suppress E-selectin expression. The constructs were composed of microRNAs (miR-E1 and miR-E2) complementary to the human E-selectin cDNA, which were directed by a minimum cis-element of the human E-selectin promoter. Transfection in human aorta endothelial cells (HAECs) with these constructs revealed that the E-selectin promoter was sufficiently activated in response to tumor necrosis factor-α (TNF-α), and miR-E1 and miR-E2 could suppress E-selectin expression resulting in the significant inhibition of leukocyte adhesion. These results suggested that the combination of the E-selectin promoter and microRNAs could allow the restricted expression of transgenes in activated endothelial cells and diminish leukocyte recruitment. [Copyright &y& Elsevier]

Presenilin 1 (PS1) forms the gamma-secretase complex with at least three components: nicastrin, APH-1, and PEN-2. This complex mediates intramembrane cleavage of amyloid precursor protein (APP) to generate beta-amyloid protein (Abeta) as well as other type 1 transmembrane proteins. Although PS1 mutations linked to familial Alzheimer's disease influence these cleavages, their biological consequences have not been fully understood. In this study, we used mRNA differential display analysis to identify a gene, denoted adoplin-1/ORMDL-1, which displays significantly reduced expression in association with PS1 mutations. Adoplin-1 and two highly homologous genes (adoplin-2, -3) constitute a gene family that encodes transmembrane proteins. The mRNA and protein levels of adoplins (particularly adoplin-1, -2) were markedly elevated in PS-deficient fibroblasts, compared to wild-type cells. Moreover, knockdown of the three adoplins by RNA interference affected maturation of nicastrin and its association with PS1. Adoplin knockdown additionally resulted in elevated levels of APP C-terminal fragments and decreased Abeta production, suggestive of reduced gamma-secretase activity. Our data collectively indicate that adoplins are unique molecules with PS-related expression and functions that may play important role(s) in the maturation and activity of the gamma-secretase complex.

CADASIL is associated with mutations in the Notch3 gene but the causal mechanisms of the disorder remain unclear. We studied effects of widely established mutations on Notch3 receptor processing and ligand-mediated activation in stable lines of HEK293 and SH-SY5Y cells expressing either human wild-type or mutant Notch3 receptor. None of the four mutations (R90C, R133C, C185R and R449C) affected quantities of the full-length, amino-terminal or carboxyl-terminal fragments and did not impair intracellular trafficking in both cell types. The Jagged 1, Jagged 2 and Delta ligand-mediated S2 site cleavage and signal transduction were also observed to be similar in both wild-type and mutants, which exhibited similar rates of degradation of full-length, amino-terminal and carboxyl-terminal fragments. Our results suggest that the arteriopathy in CADASIL is caused by other mechanisms not necessarily involving Notch3 processing and activation.

Frontotemporal dementia represents up to 10% of all dementias and is, next to Alzheimer's disease and Lewy body disease, the third most common cause of degenerative dementia. The term "frontotemporal dementia" covers a range of conditions, including Pick's disease, frontal lobe degeneration and dementia associated with motor neurone disease. Neuropathologically FTD is characterised by atrophy of the frontal and temporal lobes of the cerebral cortex, often with additional subcortical changes. Both familial and more frequently sporadic forms of FTD can be recognised. Recently, mutations in the microtubule-associated protein (tau) gene have been found in families with frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). The identification of mutations in the tau gene indicates that the protein plays a central role in the process of neurodegeneration. Epidemiology of frontotemporal dementias in Poland remains still unknown. A prevalence of tau mutations among Polish patients has not been established yet. Here, we report results of a mutational analysis of the tau gene among Polish FTD patients. No pathogenic mutation was found in the analysed sample. The study confirmed that the frequency of tau mutations is very low and depends strongly on the clinical criteria used to select patients. Mutations in the tau gene account only for a small number of FTD cases with a clear autosomal dominant pattern of disease inheritance. Therefore there should exist additionalgenetic and non-genetic factors contributing to the pathogenesis of both familial (linked and non-linked to chromosome 17) and sporadic forms of FTD.

Mutations in the microtubule-associated tau gene are responsible for frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). A reduced ability of the mutated microtubule-associated tau protein to interact with microtubules causes microtubule destabilization leading to deleterious effects on axonal transport and the formation of tau filaments. Here, we describe a new mutation of the tau gene, a T --> C transition at position +11 of the intron following exon 10 (T --> C 3'E10 +11) in the family showing frontotemporal dementia with very early age of onset (the first decade of proband's life). The T -->C 3'E10 +11 mutation caused a large increase in the proportion of transcripts containing exon 10 detected by exon-trapping analysis. Our study confirmed that the T --> C 3'E10 +11 mutation, as the other 5' splice site mutations of tau exon 10, modifies alternative splicing of exon 10.