Parks-Neurodegenerative Disease Flashcards
What are the 2 major ways to deal with misfolded or worn out proteins?
ubiquitination and proteasomes or lysosomes (autophagy)
What is the protein and location of protein involved with alzheimers?
Ab TAU
extracellular neuron
What is the protein and location of protein involved with Parkinson Diseease?
alpha-synuclein
Neurons
What is the protein and location of protein involved with amytrophic lateral sclerosis?
TDP-43
SOD-I (familial disease)
neurons
What is the protein and location of protein involved with Huntington diseease?
Huntingtin
neurons
How do you form inclusion bodies?
failed proteasomal degreadation results in soluble aggregates that are autphagycotized and results in inclusion bodies
Are there cellular consequences to protein aggregation and inclusions?
- often they elicit a stress reaction from the cell.
- often directly TOXIC to neuron
- Some aggregates are capable of behaving like prions. Aggregates derived from one neuron taken up by another neuron giving rise to more aggregates.
What does amyloidogenic proteins (misfoled proteins) turn into?
fibrils by forming beta sheet structures
What are the two major histological components of alzheimers?
neurofibrillary tangles
amyloid plaques
Where does the progressive disease of alzheimers begin?
in the hippocampus
What is the average time for alzheimers to progress to severe AD and death? How long can the progression last?
8 yrs
20 yrs
How does amyloid cause neuronal damage in alzheimers?
Amyloid precursor protein is cut by the secretase cleavage. This creates an AB monomers which will combine with other AB monomers and form oligomers and then aggregate into plaques and tangles and you end up with neuronal damage
What makes up an amyloid (senile) plaque?
composed of dystrophic neuritic processes, B-amyloid peptide, microglial cells, and astrocytes and their processes
What are neurofibrillary tangles made up of?
paired helical filaments (PHFs) of hyperphosphorylated tau protein
(blank) are intracellular aggregates of actin and actin-associated proteins first observed in neurons.
Hirano bodies
Explain why Tau is awesome until its not. How does it form neurofibrillary tangles?
Tau is a microtubile stabilizing protein. When Amyloid beta builds up in alzheimers it activated a kinase thus phosphorylating other proteins. It hyperphosphorylates Tau which makes it fall off of microtubles and thus disassembles the microtuble. In addition the tau protein then pairs up and turns into a helical filament and then forms neurofibrillary tangles.
What is the amyloid cascade hypothesis?
- > increased production/reduced degredation of AB
- > plaque formation
- > hyperphosphorylation of tau
- > NFT formation
- > synaptic dysfunction and neuron loss
- > memory loss/cognitive deficits
- > psychobehavioral impairment
- > death
What does alzheimer do to your synapses?
causes them to dysfunction
How do you check fr the present of beta-amyloid in the brain?
with amyvid (fluroescent biomarker) and a PET scan
What is a problem with the Amyloid PET (PIB) scan?
there is a lot of overlap between amyloid found in alzheimers patients and older normal people
i.e normal elderly patients have some amyloid plaques and NFT too!!
What are three biomarkers used to check for Alzheimers?
- low beta-amyloid 1-42
- high total tau protein
- elevated phosphorylated tau 181p
What are the signs and symptoms of Parkinsons?
- tremor
- masked like facies
- stooped posture
- short shuffling gate
- hips and knees slightly flexed
The (Blank) modulate the output signals from motor neurons and help coordinate and regulate motor behavior
basal ganglia
What kind of inclusion bodies will you see in parkinsons?
alpha-synuclein
The largest concentration of dopaminergic neuron cell bodies in the rbain is in the (Blank). Where do these neurons project?
What do they do?
substantia nigra
corpus striatum
coordinate movement (if degenerated cause severe tremors and muscle rigidity)
Other dopaminergic neurons in the CNS are involved in motivation and reward and hyperactivity of these neurons is associated with (blank) behavior
addictive
i.e. cocain buildups dopamine in limbic system by inhibiting Na dependent dopamine reuptake
What is the main region affected by parkinsons?
What are other regions?
substantia nigra
- striatum (caudate, putamen, substantia nigra)
- locus ceruleus
- raphe nuclei
- brainstem
- globus pallidus
- thalamus
- motor cortex
Although Parkinson’s usually shows motor-coordination type signs and symptoms, alpha synuclein can spread and do what?
What does this lead to?
‘spread’ like a prion and contribute to neuron loss in many areas of the cerebral cortex.
dementia
ALS is a motor neuron disease of what?
both upper and lower motor neurons
In ALS you get (blank) and (blank)
demyleination and sclerosis
What does “amyotrophic” refer to?
muscle atrophy, weakness and fasciulation (shows the loss of lower motor neurons in ALS)
What does “lateral sclerosis” refer to?
hardness to palpation of the lateral columns of the spinal cord in autopsy specimens where gliosis follows degeneration of corticospinal tracts-> resultin gin overactive tendon reflexes, hoffmann signs, clonus, babinski signs (shows the loss of upper motor neurons)
In patients with typical ALS, the symptoms are primarily those of (blank)
weakness
IN ALS, what is intact? What is gone?
Sensory
Motor neurons
What tract does ALS affect? What will you find here?
Corticospinal tract
and anterior horn
Gliosis
If you are looking at the anterior roots of a spinal cord of an ALS patient what will they look like?
be atrophic
If you look at the cross section of a spinal cord in an ALS patient, what will the corticospinal tracts look like? Why?
- demylination and expansion of the corticospinal tract
- cell body of motor neurons are dead leading to atrophy and demylination and the expansion i due to gliosis.
In ALS, loss of lower motor neurons results in (blank).
denervation muscle atrophy
this is amyotrophy
T or F
amyloid beta can have all sorts of configurations making it difficult to study.
T
What can amyloid beta do to NMDA receptors?
increase calcium influx resulting in signaling cascades the result in synaptic impairment
What are the two ways you can induce dopamine neuron death and thus get parkinsons?
- Drug induced (MPTP, Rotenone)
- overexpression of alpha synuclein
What are the 3 ways alpha-synuclein can damage dopamine neurons?
- Activation of ROS (resulting in apoptosis cytotoxicity)
- alpha-synuclein can form oligomers which are neurotoxic
- alpha-synuclein can form oligromers and fibrils which can form lewy body-like inclusions and damage neurons
(blank) are abnormal aggregates of protein that develop inside nerve cells in Parkinson’s disease
Lewy bodies
What disease has early disturbance in attention and visual perception, typically has delirium, visual hallucinations, delusions, rigor, autonomic dysfunction, cortical and subcortical lewy bodies, neuritic plaques, cholinergic and dopaminergic deficits?
Dementia with Lewy bodies
What disease has neuritic plaques, neurofibrillary tangles, cholinergic deficits, delusions and early impairment of memory and attention?
Alzheimers disease
What disease has autonomic dysfunction, no early cognitive impairment, rigor, bradykinesia, tremor, subcortical lewy bodies, dopaminergic deficit?
Parkinson’s disease
How can you differentiate between parkinsons and dementia with lewy bodies based on the lewy bodies?
parkinson’s lewy bodies are subcortical while dementia with lewy bodies has them located cortically and subcortically
What wil you find within the anterior horn of the spinal cord?
lower motor neurons
What causes ALS?
a defect in SOD1 gene (superoxide dismutase gene)
WHat does superoxide dismutase do?
What happens if you dont have it?
it is an antioxidant (dismantles the superoxides) and prevents damage of the oxides to cells.
-you get decreased function of glutamate transport receptors on astrocytes resulting in increased glutamate in neuron synapses and thus excitotoxicity
How can you treat ALS?
What does it do?
Riluzole
-inhibits glutamate release and blocks post-synaptic actions of NMDA receptors reducing the excitotoxicity
Syndenham’s chorea which almost are dance-like movements that some patients get following a (blank) infection
Streptococcal infection.
What part of the brain does huntingtons affect the most?
Why do you get choreo and movement problems in huntingtons?
- mainly the caudate and some of the putamen (ie the striatum)
- because it is affecting the basal ganglia
What will the brain of a huntingtons patient look like?
you will have enlarged ventricles with decreased caudate size
What is the three nucleotide sequence that is repeated in huntingtons disease?
How many times?
What does this repeated sequence code for?
CAG
36-121
a ton of glutamine which forms polyglutamine tract
What happens when you get the polyglutamine tracts due to your messed up chromosome 4 in HD?
they aggregate and create inclusions in the nucleus and increase the decay rate of certain types of neurons
