ND Flashcards
What are neurodegenerative disease commonly associated with?
→ ageing
What does earlier or later age of onset indicate about the genetic contribution?
→ greater genetic contribution
→ Later age of onset = more likely a sporadic (or idiopathic)
Are neurodegenerative diseases heterogenous or homogenous?
→ heterogeneous?
Define pleiotropic
→ producing more than one effect
What is the general pattern of neurodegenerative diseases?
→ Molecular impairment somewhere in the cell
→ Decreased transmission at synapse
→ “Dying back” of neurites (axons and/or dendrites)
→ Cell death
What is the distance between axon terminal and nucleus considered as?
→ Achilles heel
What are the common features of NDs?
→ Protein aggregation (“proteinopathies”)
→ Lysosomal dysfunction
→ Mitochondrial dysfunction
→ Associated inflammation via activation of glia
What is the most common cause of dementia?
→ Alzheimer’s
What is dementia?
→ A decline in memory and other cognitive functions that impair quality of life
What is the major hallmark of Alzheimers?
→ brain shrinkage
→ dramatic shrinkage in cortex and hippocampus
What are the proteinopathies of Alzheimers?
→ amyloid plaques
→ neurofibrillary
What are amyloid plaques?
→ Extracellular protein aggregates
→ Enriched in Aβ peptides
What are neurofibrillary tangles?
→ paired helical filaments
→ Intracellular protein aggregates
→ Enriched in Tau protein
What is Abeta peptide cleaved from?
→ transmembrane protein called amyloid beta precursor protein (APP) by proteases
What are the three proteins that can be mutated and involved in Abeta peptide processing?
→ APP
→ PSEN1
→ PSEN2
What are presenillin-1 and Presenillin-2 both a component of?
→ γ-secretase
What does tau normally bind to?
→ microtubules in axons
What does hyperphosphorylation of tau lead to and how?
→ displaced causing:
→ Tangles
→ Destabilised → microtubules
What are the three main roles of microtubules in post-mitotic cells?
→Structure/shape of cell
→ Positioning of organelles
→ Motorways for transporting vesicular cargo
Describe the tau hypothesis
→ typical late onset AD (i.e. not genetic forms of AD
→ neurofibrillary tangles are seen before amyloid plaques
→ Well correlated with cell death and progression
→ Tau is upstream Aβ