Larry hightower larry eddaybrazil2012
-
Upload
rosanepacheco73 -
Category
Health & Medicine
-
view
613 -
download
5
description
Transcript of Larry hightower larry eddaybrazil2012
Kirkwood, Nature, 2008
Cellular Stress Responses, Cytoprotection and Aging
Larry Hightower, Ph.D., FAAAS
University of Connecticut
Life expectancy around the world has increased steadily for nearly 200 years (5 hrs/day). The top countries for
longevity are shown here.
Kirkwood, Nature, 2008
Due to increased longevity and declining birth rates, we are living in a rapidly aging world
Petsko, Genome Biology, 2008
Longevity and ROS: Recent aging research using model organisms has focused on lifespan,
valuable in identifying key genes and proteins as well as generating theories.
• Longevity is influenced by environmental and genetics factors • Free radical theory of aging
“ Longevity is determined by the capacity of an organism to cope with random damages induced by radical oxygen species (ROS) ” Sohal, Free Rad Biol Med, 2002
• ROS are produced by the mitochondrial electron transport and by the Fenton
reaction (Fe2+ + H2O2 Fe3+ + OH˙+ OH-)
Our viewpoint: Aging is not a disease but rather it is a natural process for life forms
that use an oxygen-based metabolism. Oxidation (oxidative stress) is one side of the
redox reactions that drive our metabolism. Reduction (reductive stress) is the other
part and both cause damage in cells.
Our research goal is to promote healthy aging in humans. Our focus is not on
increasing lifespan directly, although this is a likely consequence.
Annual Number (in Thousands) of New Cases of Diagnosed Diabetes Among Adults Aged 18–79 Years, United States, 1980–2010 From 1980 through 2010, the number of adults in the United States aged 18–79 with newly diagnosed diabetes more than tripled from 493,000 in 1980 to over 1.7 million in 2010. The number of new cases of diabetes has increased since the early 1990s. From 2008 through 2010, the number of new cases of diagnosed diabetes has shown little change.
http://www.cdc.gov/diabetes/statistics/incidence/fig1.htm
6
Diabetes Reduces Years of
Life
Morgan, Diab Care 23: 1103, 2000
0
5
10
15
20
25
30
<35 35-44 45-54 55-64 65-74 75-84 85+
Years
Lost
Age at Diagnosis
Women
Men
Driscol, P. Chronic Wounds, 2008 Mediligence.com CAGR: compounded annual growth rate
Diabetic ulcers impede healthy aging
Chaperones, aging & diseases
- Chaperones and aging
- reduced HS response in aging
- chaperones important for protein refolding and/or degradation
- many age-related diseases, particularly neuronal diseases,are associated with protein misfolding, modification and aggregation
Core 2 Flavo
protein
Vb
α β
α
Υ
Atp6
p
Atp4
p
Atp8
p
Atp5
p
Atp7
p
3H+ AD
P
P
i H2O ATP
Intermembrane
space
Mitochondrial
matrix
Hsp23
Hsp27
Hsp26
Hsp22
ROS
ROS
ROS
Aging
Aging
[ROS]
ROS
ER
Mitochondria
Nucleus
DNA
ROS
Proteasome
Cytosol
Hsp70/Hsp40/sHsps Lisosome/ microautophagy
Tanguay and Morrow, 2008
« X » ?
Young Aged How to prevent?
Most of the following sequence of slides is from the laboratory
of Professor Robert Tanguay.
Drosophila Hsp22 overexpression
increases lifespan
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (days)
Surv
ival
(%)
+/actin-GAL4
EP(3)3247/actin-GAL4
0
10
20
30
40
50
60
70
80
90
100
0 10 20 30 40 50 60 70 80 90 100 110 120
Time (days)
Surv
ival
(%)
+/D42-GAL4
EP(3)3247/D42-GAL4
62 82 68 90
Ubiquitous (actin) Motorneurons (D42)
32 % 32 %
Morrow et al. FASEB J, 2004
Flies overexpressing Hsp22 maintain their
locomotor activity longer (healthy aging)
0
10
20
30
40
50
40 60 80
Âge des mouches (jours)
Mou
ches
plu
s hau
te q
ue
7 c
m e
n 8
sec
on
des
(%
)
+/D42-GAL4
EP(3)3247/D42-GAL4
50
20
30
40
10
0
Flie
s ab
ove
7 c
m in
8 s
eco
nd
s (%
)
40 80 60
Age of flies (days)
+/D42-GAL4
EP(3)3247/D42-GAL4
Morrow et al. FASEB J, 2004
Hsp22 overexpression (motorneurons) increases resistance to oxidative stress
(paraquat)
0
10
20
30
40
50
60
70
80
90
100
2 40 60 80
Age of flies (days)
Su
rviv
al
(%)
+/D42-GAL4
EP(3)3247/D42-GAL4
Morrow et al. FASEB J, 2004
The main functions up regulated in the mitoproteome and microarray analysis are similar even if the analysis are not
designed in the same way
Functions up regulated in the mitoproteome analysis Functions up regulated in the microarray analysis
Mitochondrial function
Complex I
Complex V - ATP pump
Defense response
Proteolysis
Mitochondrial function
Complex I
Complex V - ATP pump
Protein biosynthesis
Defense response
Proteolysis
DmHsp22
actin
A
B
Po
pu
lati
on
do
ub
lin
gs
Days
TIG-Vector
TIG-DmHsp22
DmHSP22-expressing human fibroblasts
live longer
Wadhwa et al. J Biol Chem 2010
Dm Hsp22 in human cells
DmHsp22 is functionally active in human cells
1- causes lifespan extension of primary human fibroblasts 2- increases malignant properties of human cancer cells - malignant transformation of MCF-7 breast cancer cells - higher transformation (colony forming assay) - higher mobility (invasive assay) - enhanced motility (wound scratch/invasion assay) - tumor formation in nude mice 3- increases resistance to drugs
Molecular Causes of Aging
Reactive Oxygen Species
Nutritional Glucose
Errors in biochemical
processes
Molecular Damage
HBOT
Hormesis • a process in which exposure to a low dose of a chemical agent or environmental
factor that is damaging at higher doses induces an adaptive beneficial effect on
the cell or organism
Mattson M. Ageing Res Rev. 2008 Cysper JR and Johnson TE. J Gerontol A Biol Sci Med Sci. 2002
C.elegans
Examples of Hormesis: Calorie Restriction (CR)
Colman RJ, et al. Science. (2009) 325, 201-204
Control CR
37% of Control animals died due to age
13% of CR animals died due to age
Examples of Hormesis: HBOT
HBOT protects against toxic oxygen exposure in C.elegans
Cysper JR and Johnson TE. J Gerontol A Biol Sci Med Sci. 2002
HBOT
2.72 atm
8hrs
12-16hrs HBOT
2.72 atm
20-24hrs
Age (days)
HBOT Project
UCONN-OxyHeal
OxyCure 3000 DNA Microarray Technology
Keap1
SH SH
Nrf2
Cul3 Nrf2
Ub
Ub
Ub
Ub
Ub
Proteasome
ARE
sMAF
CBP/p300
TARGET GENES •Antioxidants •Xenobiotic metabolism •Glutathione homeostasis •DNA damage recognition •Proteasome function •Inhibition of inflammation
Nrf2 Signaling pathway
nucleus
cytoplasm
Nrf-2 Antioxidant Pathway
ROC1, named ROC for RING of cullins, a ubiquitin ligase. We suggest that Keap1
negatively regulates Nrf2 function in part by targeting Nrf2 for ubiquitination by the
CUL3-ROC1 ligase and subsequent degradation by the proteasome.
HO-1, Heme oxygenase catalyzes the oxidative degradation of heme into equimolar
amounts of biliverdin, carbon monoxide, and free iron. HO-1 plays a cytoprotective
role in modulating tissue responses to injury in pathophysiological states.
TRX-1, thioredoxin-1 oxidoreductase, predominant role of Trx-1 to limit oxidative
stress directly due to reactive oxygen species scavenging and by protein–protein
interaction with key signaling molecules.
Nrf-2 transcription factor
is a crucial regulator of cellular redox
homeostasis through its capacity to induce
the expression of enzymes which detoxify
reactive oxygen species, and expression
of other antioxidant proteins. TRX-1
HO-1
TRX-1
HO-1
mTOR1 Signaling
mTOR, the mammalian form of TOR, target of rapamycin, an immunosuppressive drug.
Inhibition of TOR signaling pathway can extend lifespan.
The mTOR pathway integrates signals from nutrients, energy status and growth factors to
regulate many processes, including autophagy, ribosome biogenesis and metabolism.
AMPK, an AMP-dependent kinase, the ancient and central sensor of cellular energy
stress. It is activated by low energy conditions and then inhibits TORC-1 activity and
triggers shift to catabolic metabolism. This shields organisms from metabolic overuse
during bad times.
S6K, S6 kinase, regulator of translation initiation and elongation. Active mTOR results
in the activation of S6K and stimulates both translation initiation and elongation. S6K
deficient mice show an increased lifespan.
“TOR is absolutely essential for developmental
growth, but upon completion of development
it causes aging and age‐related diseases.”
Blagosklonny and Hall, Aging 2009.
• HBO treated cells are protected against
lethal oxidative and heat stresses.
• HBO increases expression of
antioxidant and cytoprotective genes
– HMOX1, MT, HSP, TXN, HIF1α, Nrf2
• Potential to stimulate healthy aging,
decrease toxicity after major surgery for
aged individuals, and as a preventative
therapy for other age-related diseases
(i.e.diabetes)