Cardiac rehabilitation effects on quality of life in patients after acute myocardial infarction.

Aim of this study was to investigate the significance of cardiac rehabilitation (CR) on Health Related Quality of Life ( HRQoL) in post acute myocardial infarction (AMI) patients. Methods. A total number off 110 individuals divided in 3 groups was included in the study. Group A consisted of 60 post-AMI pts participating in a CR program. It was a multidisciplinary rehabilitative approach including supervised bike exercise, with parallel education, counselling, psychological and social support, performed 3 times per week for 2 months after AMI . Group B consisted of 40 post-AMI pts not participating in any CR program while the control group C consisted of 10 apparently healthy people. HRQoL was evaluated by the Velasco-Del Barrio questionnaire. Questions on this questionnaire are reffered to 9 categories (health, sleep and rest, emotional behavior, concerns for the future, mobility, social interaction, alertness behavior, communication, work and leisure time). A 5-point scale (1=all of the time, 5=none of the time) and a special (1 to 8) coefficient for each parameter were used for the evaluation of each parameter. The highest score of 220 indicates the poorest QL. Results. Group A pts had better score of HRQoL as compared to Group B (94±3 vs 114±3, p<0.001) and slightly worse than Group C pts (94±4 vs 69±3, p<0.01).Significant difference was found among Group A and B pts regarding the most important evaluated parameters such as symptoms (17±6.8 vs 22±6.5, p<0.001) and social behavior (21±4.2 vs 23±5.5, p<0.0001).Conclusion. It is concluded that participation in a multidisciplinary CR program significantly improves HRQoL in post AMI pts. All these pts must urged to take part in such programs.

Regulation of alternative splicing of human tau exon 10 by phosphorylation of splicing factors.

Tau is a microtubule-associated protein whose transcript undergoes regulated splicing in the mammalian nervous system. Exon 10 of the gene is an alternatively spliced cassette that is adult-specific and encodes a microtubule-binding domain. Mutations increasing the inclusion of exon 10 result in the production of tau protein which predominantly contains four microtubule-binding repeats and were shown to cause frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). Here we show that exon 10 usage is regulated by CDC2-like kinases CLK1, 2, 3, and 4 that phosphorylate serine-arginine-rich proteins, which in turn regulate pre-mRNA splicing. Cotransfection experiments suggest that CLKs achieve this effect by releasing specific proteins from nuclear storage sites. Our results show that changing pre-mRNA-processing pathways through phosphorylation could be a new therapeutic concept for tauopathies.

The STAR/GSG family protein rSLM-2 regulates the selection of alternative splice sites.

We identified the rat Sam68-like mammalian protein (rSLM-2), a member of the STAR (signal transduction and activation of RNA) protein family as a novel splicing regulatory protein. Using the yeast two-hybrid system, coimmunoprecipitations, and pull-down assays, we demonstrate that rSLM-2 interacts with various proteins involved in the regulation of alternative splicing, among them the serine/arginine-rich protein SRp30c, the splicing-associated factor YT521-B and the scaffold attachment factor B. rSLM-2 can influence the splicing pattern of the CD44v5, human transformer-2beta and tau minigenes in cotransfection experiments. This effect can be reversed by rSLM-2-interacting proteins. Employing rSLM-2 deletion variants, gel mobility shift assays, and linker scan mutations of the CD44 minigene, we show that the rSLM-2-dependent inclusion of exon v5 of the CD44 pre-mRNA is dependent on a short purine-rich sequence. Because the related protein of rSLM-2, Sam68, is believed to play a role as an adapter protein during signal transduction, we postulate that rSLM-2 is a link between signal transduction pathways and pre-mRNA processing.

Brain expression of presenilins in sporadic and early-onset, familial Alzheimer's disease.

BACKGROUND: Mutations in the presenilin proteins cause early-onset, familial Alzheimer's disease (FAD). MATERIALS AND METHODS: We characterized the cellular localization and endoproteolysis of presenilin 2 (PS2) and presenilin 1 (PS1) in brains from 25 individuals with presenilin-mutations causing FAD, as well as neurologically normal individuals and individuals with sporadic Alzheimer's disease (AD). RESULTS: Amino-terminal antibodies to both presenilins predominantly decorated large neurons. Regional differences between the broad distributions of the two presenilins were greatest in the cerebellum, where most Purkinje cells showed high levels of only PS2 immunoreactivity. PS2 endoproteolysis in brain yielded multiple amino-terminal fragments similar in size to the PS1 amino-terminal fragments detected in brain. In addition, two different PS2 amino-terminal antibodies also detected a prominent 42 kDa band that may represent a novel PS2 form in human brain. Similar to PS1 findings, neither amino-terminal nor antiloop PS2 antibodies revealed substantial full-length PS2 in brain. Immunocytochemical examination of brains from individuals with the N141I PS2 mutation or eight different PS1 mutations, spanning the molecule from the second transmembrane domain to the large cytoplasmic loop domain, revealed immunodecoration of no senile plaques and only neurofibrillary tangles in the M139I PS1 mutation stained with PS1 antibodies. CONCLUSIONS: Overall presenilin expression and the relative abundance of full-length and amino-terminal fragments in presenilin FAD cases were similar to control cases and sporadic AD cases. Thus, accumulation of full-length protein or other gross mismetabolism of neither PS2 nor PS1 is a consequence of the FAD mutations examined.

The splicing determinants of a regulated exon in the axonal MAP tau reside within the exon and in its upstream intron.

Tau is a microtubule-associated protein whose transcript undergoes complex regulated splicing in the mammalian nervous system. Exon 6 of the gene is an alternatively spliced cassette whose expression profile is distinct from that of the other tau regulated exons, implying the utilization of distinct regulatory factors. Previous work had established the use of cryptic splice sites within exon 6 and the influence of flanking exons on the ratio of exon 6 variants. The present work shows that, in addition to the previously identified participants, the ratio of exon 6 isoforms is affected by: (1) suppression of the cryptic sites, (2) deletions of the upstream intron, and (3) the splicing regulators PTB and U2AF, both of which act on the branch point/polypyrimidine tract region. These results strongly suggest that factors binding immediately upstream of exon 6 are involved in regulation of this exon. They also lead to the conclusion that splicing of exon 6 is primarily governed by multiple branch points.

A retinoic acid synthesizing enzyme in ventral retina and telencephalon of the embryonic mouse.

Most retinoic acid (RA) in the embryonic mouse is generated by three retinaldehyde dehydrogenases (RALDHs). RALDH1 (also called E1, AHD2 or ALDH1) is expressed in the dorsal retina, and RALDH2 (V2, ALDH11) generates most RA in the embryonic trunk. The third one, RALDH3 (V1), synthesizes the bulk of RA in the head of the early embryo. We show here that RALDH3 is a mouse homologue to ALDH6, an aldehyde dehydrogenase cloned from adult human salivary gland (Hsu, L.C., Chang, W.-C., Hiraoka, L., Hsien, C.-L., 1994. Molecular cloning, genomic organization, and chromosomal localization of an additional human aldehyde dehydrogenase gene, ALDH6. Genomics 24, 333-341), which was recently reported to act as a RALDH (Yoshida, A., Rzhetsky, A., Hsu, L.C., Chang, C., 1998. Human aldehyde dehydrogenase gene family. Eur. J. Biochem. 251, 549-557). RALDH3 expression begins in the surface ectoderm over the optic recess. In rapidly changing expression patterns it labels the appearance of several ectodermal structures: it marks the formation of the lens and the olfactory organ from ectodermal placodes, and it delineates the beginning eyelid field. Within the optic vesicle, RALDH3 is expressed in the ventral retina and the dorsal pigment epithelium. In the telencephalon, RALDH3 is expressed at high levels in the lateral part of the ganglionic eminence. From here it extends via the piriform cortex into the lower part of the septum. Of the three RALDHs, RALDH3 shows the strongest predilection for epithelia.

Complex regulation of tau exon 10, whose missplicing causes frontotemporal dementia.

Tau is a microtubule-associated protein whose transcript undergoes complex regulated splicing in the mammalian nervous system. Exon 10 of the gene is an alternatively spliced cassette that is adult-specific and that codes for a microtubule binding domain. Recently, mutations that affect splicing of exon 10 have been shown to cause inherited frontotemporal dementia (FTDP). In this study, we establish the endogenous expression patterns of exon 10 in human tissue; by reconstituting naturally occurring FTDP mutants in the homologous context of exon 10, we show that the cis determinants of exon 10 splicing regulation include an exonic silencer within the exon, its 5' splice site, and the relative affinities of its flanking exons to it. By cotransfections in vivo, we demonstrate that several splicing regulators affect the ratio of tau isoforms by inhibiting exon 10 inclusion.

Tau gene polymorphisms and apolipoprotein E epsilon4 may interact to increase risk for Alzheimer's disease.

In an effort to analyze the genetic role of tau in Alzheimer's disease (AD), 17 polymorphisms were identified. Eleven of these polymorphisms were in complete linkage disequilibrium and segregated as two haplotypes, A and B. The A and B haplotypes were investigated in 269 AD cases and 238 controls from two different sources, a clinic-based group (mean age of onset 65+/-9 years), and a population-based group (mean age of onset 80+/-5 years). A synergistic effect between the common tau genotype AA and apolipoprotein E (APOE epsilon4) was found in the clinic-based AD group. Our study suggests that the common tau genotype AA may interact with APOE epsilon4 in increasing the risk of AD in a subgroup of the AD population.

Pathogenic implications of mutations in the tau gene in pallido-ponto-nigral degeneration and related neurodegenerative disorders linked to chromosome 17.

Pallido-ponto-nigral degeneration (PPND) is one of the most well characterized familial neurodegenerative disorders linked to chromosome 17q21-22. These hereditary disorders are known collectively as frontotemporal dementia (FTD) and parkinsonism linked to chromosome 17 (FTDP-17). Although the clinical features and associated regional variations in the neuronal loss observed in different FTDP-17 kindreds are diverse, the diagnostic lesions of FTDP-17 brains are tau-rich filaments in the cytoplasm of specific subpopulations of neurons and glial cells. The microtubule associated protein (tau) gene is located on chromosome 17q21-22. For these reasons, we investigated the possibility that PPND and other FTDP-17 syndromes might be caused by mutations in the tau gene. Two missense mutations in exon 10 of the tau gene that segregate with disease, Asn279(Lys) in the PPND kindred and Pro301(Leu) in four other FTDP-17 kindreds, were found. A third mutation was found in the intron adjacent to the 3' splice site of exon 10 in patients from another FTDP-17 family. Transcripts that contain exon 10 encode tau isoforms with four microtubule (MT)-binding repeats (4Rtau) as opposed to tau isoforms with three MT-binding repeats (3Rtau). The insoluble tau aggregates isolated from brains of patients with each mutation were analyzed by immunoblotting using tau-specific antibodies. For each of three mutations, abnormal tau with an apparent Mr of 64 and 69 was observed. The dephosphorylated material comigrated with tau isoforms containing exon 10 having four MT-binding repeats but not with 3Rtau. Thus, the brains of patients with both the missense mutations and the splice junction mutation contain aggregates of insoluble 4Rtau in filamentous inclusions, which may lead to neurodegeneration.

Differences in a dinucleotide repeat polymorphism in the tau gene between Caucasian and Japanese populations: implication for progressive supranuclear palsy.

Previous studies of a tau polymorphism in Caucasian subjects with progressive supranuclear palsy (PSP) showed an over-representation of one genotype, A0/A0, versus normal control subjects. This result suggested that tau may be playing a genetic role in the progression of PSP. This study examines whether the over-representation of A0/A0 is Caucasian-specific or universal to PSP. Unfortunately, we found this dinucleotide repeat was relatively non-polymorphic in Japanese subjects. As a result, the genotypes were virtually the same, A0/A0, between Japanese PSP and control subjects. However, this outcome, albeit negative, does suggest two possible roles of the tau gene in PSP pathogenesis: (1) the role of this dinucleotide repeat in PSP may be different between Caucasian and Japanese populations or (2) this repeat may not be causal for PSP but represents a marker for other molecular genetic risk factors within or close to the tau gene on chromosome 17.

Tau is a candidate gene for chromosome 17 frontotemporal dementia.

Frontotemporal dementia with parkinsonism, chromosome 17 type (FTDP-17), a recently defined disease entity, is clinically characterized by personality changes sometimes associated with psychosis, hyperorality, and diminished speech output, disturbed executive function and nonfluent aphasia, bradykinesia, and rigidity. Neuropathological changes include frontotemporal atrophy often associated with atrophy of the basal ganglia, substantia nigra, and amygdala. Neurofibrillary tangles (NFTs) are seen in some but not all families. Inheritance is autosomal dominant and the gene has been regionally localized to 17q21-22 in a 2- to 4-centimorgan (cM) region flanked by markers D17S800 and D17S791. The gene for tau, the primary component of NFTs, is located in the same region of chromosome 17. Tau was evaluated as a candidate gene. Physical mapping studies place tau within 2 megabases or less of D17S791, but it is probably outside the D17S800-D17S791 FTDP-17 interval. DNA sequence analysis of tau coding regions in affected subjects from two FTDP-17 families revealed nine DNA sequence variants, eight of which were also identified in controls and are thus polymorphisms. A ninth variant (Val279Met) was found in one FTDP-17 family but not in the second FTDP-17 family. Three lines of evidence indicate that the Val279Met change is an FTDP-17 causative mutation. First, the mutation site is highly conserved, and a normal valine is found at this position in all three tau interrepeat sequences and in other microtubule associated protein tau homologues. Second, the mutation co-segregates with the disease in family A. Third, the mutation is not found in normal controls.

Association of missense and 5'-splice-site mutations in tau with the inherited dementia FTDP-17.

Thirteen families have been described with an autosomal dominantly inherited dementia named frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), historically termed Pick's disease. Most FTDP-17 cases show neuronal and/or glial inclusions that stain positively with antibodies raised against the microtubule-associated protein Tau, although the Tau pathology varies considerably in both its quantity (or severity) and characteristics. Previous studies have mapped the FTDP-17 locus to a 2-centimorgan region on chromosome 17q21.11; the tau gene also lies within this region. We have now sequenced tau in FTDP-17 families and identified three missense mutations (G272V, P301L and R406W) and three mutations in the 5' splice site of exon 10. The splice-site mutations all destabilize a potential stem-loop structure which is probably involved in regulating the alternative splicing of exon10. This causes more frequent usage of the 5' splice site and an increased proportion of tau transcripts that include exon 10. The increase in exon 10+ messenger RNA will increase the proportion of Tau containing four microtubule-binding repeats, which is consistent with the neuropathology described in several families with FTDP-17.

Splicing of a regulated exon reveals additional complexity in the axonal microtubule-associated protein tau.

Tau is a microtubule-associated protein whose transcript undergoes complex regulated splicing in the mammalian nervous system. Exon 6 of the gene is an alternatively spliced cassette whose expression pattern and splicing regulation had not been previously analyzed in the human. The expression profile of exon 6 is completely different from that of the better-analyzed exons 2, 3, 4A, and 10, implying the utilization of distinct regulatory factors. The default splicing behavior of the exon had demonstrated the existence of what were initially considered cryptic splice sites. However, analysis of the expression pattern of exon 6 suggests that these splice sites are utilized in certain human tissues and, if translated, would result in a radically altered tau protein. Lastly, expression of exon 6 minigene constructs in cells indicates that its flanking exons are involved in its inclusion and in the modulation of the ratio of its variants.

Localization of frontotemporal dementia with parkinsonism in an Australian kindred to chromosome 17q21-22.

An Australian family with autosomal dominant presenile nonspecific dementia was recently described. The disease results in behavioral changes, usually disinhibition, followed by the onset of dementia accompanied occasionally by parkinsonism. Twenty-eight affected individuals were identified with an age of onset of 39 to 66 years (mean, 53 +/- 8.9 years). We mapped the disease locus to an approximately 26-cM region of chromosome 17q21-22 with a maximum two-point LOD score of 2.87. Affected individuals share a common haplotype between markers D17S783 and D17S808. This region of chromosome 17 contains the loci for several neurodegenerative diseases that lack distinctive pathological features, suggesting that these dementias, collectively referred to as frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), are caused by mutations in the same gene. The entire coding region of five genes, mapped to the FTDP-17 candidate region, were also sequenced. This analysis included the microtubule-associated protein tau that is the major component of the paired helical filaments observed in Alzheimer's disease. No pathogenic mutations were identified in either the tau gene or in any of the other genes analyzed.

Mapping of a disease locus for familial rapidly progressive frontotemporal dementia to chromosome 17q12-21.

Familial frontotemporal dementia (FTD) is a complex disorder with lack of distinctive histopathological markers found in other types of dementia. Most of the linkage reports from FTD families map the disease loci to chromosome 17q21-22. However, FTD is genetically heterogeneous, as linkage also has been reported to chromosome 3. In the present study, we investigated the genetics of a Swedish family with an early-onset type of rapidly progressive FTD, associated with muscular rigidity and akinetic movements. Neuropathological features such as severe frontal lobe degeneration, spongy changes, and gliosis were present in affected family members. We here report probable linkage to chromosome 17q12-21 with a maximum two-point lod score of 2.76 at theta = 0 for marker D17S806, and a peak multipoint lod score of 2.86 for the same marker. Linkage to chromosome 3 was excluded, as two-point lod scores of -2.79, and -2.27 at theta = 0.01 for markers D3S1603 and D3S1552, respectively, were obtained. Sequencing of the translated exons of a strong candidate gene in the linked region of chromosome 17, the tau gene, failed to identify any mutations segregating with the disease.

Genetic evidence for the involvement of tau in progressive supranuclear palsy.

A dinucleotide repeat polymorphism in a tau intron was identified and used in a case-control study to analyze the genetic association of tau with several neurodegenerative diseases with tau pathology. Subjects with the homozygous tau AO alleles were excessively represented in the progressive supranuclear palsy (PSP) group, compared with the age-matched healthy control group. Consequently, this allele is more frequently found in PSP than in a group of healthy subjects. This trend was not found in Alzheimer's disease or parkinsonism-dementia complex of Guam, both of which are accompanied by major tau pathology. The result suggests a possible involvement of tau in the pathogenesis of PSP.

A tau promoter region without neuronal specificity.

The microtubule-associated protein tau is produced from a 6-kb mRNA expressed primarily in neurons. A 2-kb tau mRNA has also been characterized, which produces a tau isoform that localizes to the nucleus, and an 8-kb mRNA is expressed in the PNS. Mapping and sequencing of the human tau gene start showed that it has an unusually GC-rich 5'-untranslated region coded by a single untranslated exon (designated -1). Primer extensions and expression assays indicated that upstream of exon -1 is a promoter that is not neuron specific. This region contains consensus binding sites for transcription factors AP2, Sp1, and GCF.

Relative exon affinities and suboptimal splice site signals lead to non-equivalence of two cassette exons.

Tau is a microtubule-associated protein whose transcript undergoes complex regulated splicing in the mammalian nervous system. Exons 2 and 3 of the gene are alternatively spliced cassettes in which exon 3 never appears independently of exon 2. Expression of tau minigene constructs in cells indicate that exon 2 resembles a constitutive exon, while a suboptimal branch point connected to exon 3 inhibits inclusion of exon 3 in the mRNA. Splicing of the two tau exons is controlled by their relative affinities for each other versus the affinities of their flanking exons for them.

The exon trapping assay partly discriminates against alternatively spliced exons.

A cosmid containing eight exons of the gene coding for the microtubule-associated tau protein was subjected to the exon trapping assay. All the constitutive exons contained in the cosmid (4, 5, 7 and 9) were efficiently captured regardless of size. Of the four alternatively spliced exons, three (3, 4A and 8) were not isolated by the assay, but the behavior of exon 6 depended on the identity of its flanking exons.

Structure and novel exons of the human tau gene.

The microtubule-binding protein tau is important in establishing and maintaining neuronal morphology and is a major component of the neurofibrillary tangles (NFTs) characteristic of Alzheimer's brain. The neuron-specific tau transcript undergoes complex alternative splicing. The human tau gene has been cloned and mapped. The restriction analysis and partial sequencing of the gene shows that it contains (1) four alternatively spliced exons previously described in rodent and bovine but not in human tau cDNAs and (2) two CpG islands, one associated with the promoter region, the other with exon 9. Examination of human tau mRNA indicates that the human cerebrocortical splicing pattern differs from that previously reported for the murine and bovine tau mRNAs, despite conserved exon organization in all three genes.