Synaptic changes in frontotemporal lobar degeneration: correlation with MAPT haplotype and APOE genotype
S J Connelly1, E B Mukaetova-Ladinska, Z Abdul-All
1Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK.
Neuropathology and Applied Neurobiology
|November 16, 2010
Summary
Frontotemporal lobar degeneration (FTLD) shows increased synaptophysin and decreased SNAP-25 proteins compared to Alzheimer's disease (AD) and controls. Genetic factors like APOE and MAPT influence these synaptic changes in FTLD.
Area of Science:
- Neuroscience
- Neuropathology
- Genetics
Background:
- Frontotemporal lobar degeneration (FTLD) and Alzheimer's disease (AD) are neurodegenerative disorders with distinct pathological features.
- Synaptic dysfunction is implicated in the cognitive and non-cognitive symptoms of these diseases.
- Understanding synaptic changes and their genetic underpinnings is crucial for developing targeted therapies.
Purpose of the Study:
- To quantify synaptic protein levels (synaptophysin and SNAP-25) in the frontal lobe of FTLD and AD patients.
- To investigate the relationship between these synaptic changes and APOE genotype and MAPT haplotype.
- To differentiate synaptic alterations in FTLD from those in AD and healthy controls.
Main Methods:
- Immunohistochemical analysis of frontal neocortex (BA9) from post-mortem brains.
- Study included subjects with FTLD (n=20), AD (n=10), and age-matched controls (n=9).
- Quantification of synaptophysin and SNAP-25 protein expression.
Main Results:
- FTLD patients exhibited significantly increased synaptophysin and depleted SNAP-25 compared to AD patients and controls (P < 0.001).
- Synaptophysin up-regulation in FTLD was disease-specific and not affected by age or atrophy.
- SNAP-25 depletion in FTLD was influenced by family history, tau status, gender, APOE genotype (ε4 allele), and MAPT haplotype (H2).
Conclusions:
- Synaptic expression in FTLD is modulated by genetic factors, including APOE and MAPT, necessitating their consideration in future research.
- The selective loss of SNAP-25 in FTLD may correlate with the disease's core non-cognitive clinical features.
- These findings highlight distinct synaptic protein alterations in FTLD, offering insights into disease mechanisms.
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