Cell Death Flashcards
What is the difference between apoptosis and necrosis
necrosis is a pathological process which effects solid masses of tissue and induces a inflammatory response
apoptosis is basically programmed cell death but different - It causes the fragmentation of DNA
what enzymes mediate the DNA fragmentation process
ICAD - inhibitor of caspase activated DNase0
PARP - Poly (ADP-ribose) polymerase
what is required for the recognition by macrophages and non-professional phagocytes
clearance by apoptotic cells by macrophages requires reorganisation of phosphatidylserine
what are some extrinsic causes of apoptosis
receptor interaction
T cells
cytoplasmic signals
caspase cascade
what are some intrinsic causes of apoptosis
stress metabolic stress endogenous activation mitochondrial involvement DNA damage and p53
examples of extrinsic causes
TNF Family
Fas CD95
Inflammation
T cell mediated inducement of apoptosis
involves perforin and granzymes and cytoplasmic activation
this occurs in viral infection and transplantation rejection
anoikins
- Death after losing contact with basement membrane/extra cellular matrix
- Apoptosis morphology
Pyroptosis
• Microbial trigger eg Salmonella • Pattern recognition receptors
– NOD like and Toll like receptors
• Some features similar to both apoptosis and
necrosis
– Caspase 1 activation, not caspase 3
– Nuclear fragmentation but not cytoplasmic blebbing
– Pro-inflammatory
examples of where apoptosis has gone wrong
Autoimmune disease Cancer
Neurodegeneration
• Can pathway components be drug targets?
– Bcl2 in lymphoma
– caspase 3 in Alzheimer Disease
– IAP in cancer
caspase which destroys genetic information
cleave ICAD
caspase that prevents DNA repair
cleave PARP
caspase which causes the breakdown of nuclear architecture
leave LAMIN
Caspase which causes the breakdown of cytoplasmic architecture
cleave KERATIN
Abnormal Bcl2 expression can contribute to
cancer
