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J A Sluijs

Publications and source records attributed to J A Sluijs.

6 recordsLinked to original sources
PubMed2004

Frame-shifted amyloid precursor protein found in Alzheimer's disease and Down's syndrome increases levels of secreted amyloid beta40.

Frame-shifted amyloid precursor protein (APP(+1)), which has a truncated out-of-frame C-terminus, accumulates in the neuropathological hallmarks of patients with Alzheimer's disease pathology. To study a possible involvement of APP(+1) in the pathogenesis of Alzheimer's disease, we expressed APP695 and APP(+1) in the HEK293 cell-line and studied whether the processing of APP695 was affected. APP(+1) is a secretory protein, but high expression of APP695 and APP(+1) results in the formation of intracellular aggregate-like structures containing both proteins and Fe65, an adaptor protein that interacts with APP695. APP(+1) is shown to interact with APP695, suggesting that these structures consist of functional protein complexes. Such an interaction can also be anticipated in post-mortem brains of young Down's syndrome patients without any sign of neuropathology. Here we observed APP(+1) immunoreactivity in beaded fibres. Additional support for functional consequences on the processing of APP695 comes from a 1.4-fold increase in levels of secreted amyloid beta40 in cells co-expressing APP695 and APP(+1), although APP(+1) itself does not contain the amyloid beta sequence. Taken together, these data show that co-expression of APP695 and APP(+1) affects the processing of APP695 in a pro-amyloidogenic way and this could gradually contribute to Alzheimer's disease pathology, as has been implicated in Down's syndrome patients.

Adult↗
PubMed2003

Neuronal expression of GFAP in patients with Alzheimer pathology and identification of novel GFAP splice forms.

Glial fibrillary acidic protein (GFAP) is considered to be a highly specific marker for glia. Here, we report on the expression of GFAP in neurons in the human hippocampus. Intriguingly, this neuronal GFAP is coded by out-of-frame splice variants and its expression is associated with Alzheimer pathology. We identified three novel GFAP splice forms: Delta 135 nt, Delta exon 6 and Delta 164 nt. Neuronal GFAP is mainly observed in the pyramidal neurons of the hippocampus of Alzheimer and Down syndrome patients and aged controls, but not in neurons of patients suffering from hippocampal sclerosis. Apparently, the hippocampal neurons in patients with Alzheimer's disease pathology are capable of expressing glia-specific genes.

Alternative Splicing↗
PubMed2001

Mutant ubiquitin expressed in Alzheimer's disease causes neuronal death.

Ubiquitin-B+1 (UBB+1) is a mutant ubiquitin that accumulates in the neurones of patients with Alzheimer's disease (AD). Here we report on the biochemical and functional differences between ubiquitin and UBB+1 and the effect of the mutant protein on neuronal cells. UBB+1 lacks the capacity to ubiquitinate, and although it is ubiquitinated itself, UBB+1 is not degraded by the ubiquitin-proteasomal system and is quite stable in neuronal cells. Overexpression of UBB+1 in neuroblastoma cells significantly induces nuclear fragmentation and cell death. Our results demonstrate that accumulation of UBB+1 in neurones is detrimental and may contribute to neuronal dysfunction in AD patients.

Adenosine Triphosphate↗
PubMed1998

Frameshift mutants of beta amyloid precursor protein and ubiquitin-B in Alzheimer's and Down patients.

The cerebral cortex of Alzheimer's and Down syndrome patients is characterized by the presence of protein deposits in neurofibrillary tangles, neuritic plaques, and neuropil threads. These structures were shown to contain forms of beta amyloid precursor protein and ubiquitin-B that are aberrant (+1 proteins) in the carboxyl terminus. The +1 proteins were not found in young control patients, whereas the presence of ubiquitin-B+1 in elderly control patients may indicate early stages of neurodegeneration. The two species of +1 proteins displayed cellular colocalization, suggesting a common origin, operating at the transcriptional level or by posttranscriptional editing of RNA. This type of transcript mutation is likely an important factor in the widely occurring nonfamilial early- and late-onset forms of Alzheimer's disease.

Aged↗
PubMedDate not supplied

Molecular misreading: a new type of transcript mutation expressed during aging.

Dinucleotide deletions (e.g. DeltaGA, DeltaGU) are created by molecular misreading in or adjacent to GAGAG motifs of neuronal mRNAs. As a result, the reading frame shifts to the +1 frame, and so-called "+1 proteins" are subsequently synthesized. +1 Proteins have a wild-type N-terminus, but an aberrant C-terminus downstream from the site of the dinucleotide deletion. Molecular misreading was discovered in the rat vasopressin gene associated with diabetes insipidus and subsequently in human genes linked to Alzheimer's disease (AD), e.g. beta amyloid precursor protein (betaAPP) and ubiquitin-B (UBB). Furthermore, betaAPP(+1) and UBB(+1) proteins accumulate in the neuropathological hallmarks (i.e. in the tangles, neuritic plaques, and neuropil threads) of AD. As these +1 proteins were also found in elderly nondemented controls, but not in younger ones (<51 years), molecular misreading in nondividing cells might act as a factor that only becomes manifest at an advanced age. Frameshift mutations (UBB(+1)) and pretangle staining (Alz-50 and MC1) seem to occur independently of each other during early stages of AD. We recently detected +1 proteins, not only in proliferating cells present in non-neuronal tissues such as the liver and epididymis, but also in neuroblastoma cell lines. These observations suggest that molecular misreading is a general source of transcript errors that are involved in cellular derangements in various age-related pathologies.

Aging↗