lecture 8- aging and senescence Flashcards
(33 cards)
what is senescence
age related decline in fucntion
what is evidence that aging is just down to wear and tear
in c elegans, their muscles decline so they just cant eat
what is evidence that aging is down to genetic factors
in salmon, they lay their eggs then die immediately
what is the disposable soma theory
as soon as an individual cant reproduce or help their offspring, there is no natural selection against aging of that individual
what are the 3 main senescene factors
metabolism
ROS
DNA damage
what does a high metabolism lead to and why
short lifespan due to ROS production
discuss the contradicitng theories of thr effects of ROS production
ROS increases aging -> resistance to oxidative stress is induced by longevity genes
ROS decreases aging -> in worms it has been shown that ROS increases lifespan
what is PARP and what does it cause
an enzyme highlighting where DNA damage has occured
descreases NAD so leads to cell death
what do senescent cells lead to
inflammation
tissue remodelling
paracrine senescence
why are low levels of ROS actually good for the body
they alert cells to initiate protective responses
why are high levels of antioxidants actually bad
they supress all ROS so the cells dont know when to respond at all
what does blocking of the IGF pathway do
extends lifespan
what can the IGF pathway be blocked by
dietary restriction
GH receptor mutants
where is FOXO1 when insulin is high
out the nucleus, turned off
where is FOXO1 when insulin is low
in nucleus , active
what does FOXO1 downregulate
insluin like genes
what is TOR
an amino acid and nutrient sensor that stimulates growth when deactivated and blocks autophagy
what happens to the TOR pathway when stess occurs in the cells
it blocks the TOR pathway and so decreases growth
what happens to the TOR pathway when growth factors are found
activates pathway so stimulates growth
what does blocking insulin pathways do to the TOR pathway
inactivate it
what are sirtuins
NAD dependant protein deacetylases
extend life when overexpressed
what are sir proteins activated by and what do they cause
activated by resveratol
at as insulin independant activators of FOXO/Daf16 which act to downregulate IGF pathway
does NAD increase or decrease with age
decrease
which signals are sent from the gonds to promote longevity
steroidal hormones
DAF12 nuclear hormones
