Potential Transformational Mission
Health and Performance Benefits of
Cell Stress Response Upregulation
D. B. Gillis MD PhD MPH
Susana B. Zanello, PhD
UTMB-NASA JSC Aerospace Medicine Grand
Rounds
July 28, 2009
1
From Thermal Exposure Study to
Mission Risk Mitigation
Preview
• Recap of recent Shuttle middeck thermal risk characterization and
mitigations
• Addressing the lack of thermal cognitive impairment data for
spacecraft design and operation
•Correlating cellular indices of thermal stress to core temperature and
measures of cognitive impairment
• Identifying the broad cross-tolerance benefits of thermal acclimation
• Pharmacological surrogates for calorie restriction, heat shock and
acclimatization
2
Partial List of Earlier Participants
Douglas Hamilton, MD PhD MSc E.
Eng
Wyle Integrated Science & Engineering
Flight Surgeon
Stana Ilcus, MD
NASA JSC Flight Surgeon,
Lt Col, USAF
Grant Bue
Crew & Thermal Systems, NASA JSC
Larry Kuznetz, PhD
Universities Space Research Alliance
Chang Son, PhD
Boeing
Phil Stepaniak, MD
NASA JSC Flight Surgeon
J. D. Polk, DO, MS
NASA JSC Space Medicine Manager
Terry Guess
Wyle Integrated Science & Engineering
Jason Norcross, MS
Wyle Integrated Science & Engineering
7/29/2009
David Gillis, AsMA Annual Meeting 2009
3
80
Center of Middeck
70
60
Temperature
varied widely in Orbiter middeck
Sleep Sta Air Outlet
50
Volume-averaged ppCO2 of Mid-deck
7.5
7.0
6.5
ppCO2 (mm Hg)
6.0
6.28 mmHg
@ 5.5 hrs
5.5
5.0
4.5
4.0
3.5
3.0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Time (hr)
The concentration level for at 5.5 hours. The volume-averaged ppCO2 is equal to 6.28 mmHg.
What is the relationship of this single point average to
the inspired micro-environment of the crewmember?
Case 1: ppCO2 at Y-sections (5.5 hours)
Section Y2
ppCO2,
mmHg
Off-scale (>13.5)
ppCO2 values at face
are shown in white
Section Y3
Section Y4
CFD model Chang Son (Boeing) at NASA
JSC as part of Return to Flight studies
after the loss of Shuttle Columbia to
consider impact of 7 crew in the mid
deck during a Rescue flight.
Enter the Computation Fluid Dynamics (CFD) Model
• CFD uses numerical methods and algorithms to model millions of
points in the volume of interest
In this presentation, over 4 million nodes for CO2 and air velocity models, and over 2
million nodes in cabin air temperature and integrated cooling unit air flow models
This CFD model was run by Chang Son (Boeing) at NASA JSC
as part of Return to Flight studies after the loss of Shuttle
Columbia to consider impact of 7 crew in the mid deck
during a Rescue flight.
Pathlines issued from the nadir “duffy”duct
70
60
50
40
30
20
10
0
Outlet
Registers
Flow
Toward
flight deck
Air Velocity magnitude distributions at Y-sections
Case 1
Marked fore to aft decreases in air
velocity in the modeled Rescue
mid deck ‘ditch’ section
ft/min
Section Y2
Section Y3
Graphics Courtesy
of Boeing &
Chang Son, PhD
7/29/2009
Boeing
Section Y4
David Gillis, AsMA Annual Meeting 2009
9
Six Basic Environmental Variable That Affect Human
Response to A Thermal Environment
1. Air Temperature
2. Radiant Temperature
3. Humidity
4. Air Movement
5. Human Metabolic Heat Generation
6. Human Clothing Being Worn
Body Thermal Properties
• Geometric-thermal relationships of body parts:
– Heat production a function of tissue volume
– Heat loss a function of tissue surface area
– Sphere has greatest ratio of volume to surface
area: more heat preservation
– Cylinder has lower ratios of volume to surface
area: more heat loss
– Ratio of volume to surface area determines
thermal homeostasis
Fault Tree Analysis for Crew Thermal Environment Failures
Crewmember thermal stress resulting in
discomfort, cognitive or physical impairment for
required crewmember task performance
OR
Excess incident radiant
temperature after correction for
orientation of crewmember
Air temperature at the crew
body surface is excessive
Excess of direct, diffused, scattered or
reflected solar radiation from sun or
surface
Suit ensemble causes excessive
barrier to heat rejection of the
crewmember
Resting metabolic thermal load
of the crew member exceeds
system design specs
Thermal load of crew activity
exceeds system design specs
Air velocity and turbulence
intensity is inadequate
Adequate, timely medical
recovery is not available
Difference in partial vapor
pressure of H2O at the skin
and boundary environment is
inadequate
AND
OR
Crewmember thermal
tolerance reduced by a
medial disorder
Primary or secondary
ECLSS failure
Sum of crew cabin thermal loads
exceeds ECLSS capacity
Deficient crewmember thermal
tolerance (genetic or psychological)
D. B. Gillis, April 03, 2009
11 person rescue Shuttle re-entry, no
wave-off-forecast middeck temp profile,
comparing 3 ICU/TELC configurations
Cold Soak,
previous nite
Suit-Up
Region of Interest
Re-Entry
Cabin
Nominal Temp
Limit, 75 F
7/29/2009
David Gillis, AsMA Annual Meeting 2009
13
Follow-on Analysis – Mid deck CFD
•
Max local temp:
112 F
Graphics Courtesy of Boeing &
Chang Son, PhD
7/29/2009
David Gillis, AsMA Annual Meeting 2009
CFD Boeing and
Chang Son, PhD
14
Legacy models
predicted 77⁰F
highest temp, CFD
showed 112 ⁰F
After 13
mitigations,
highest temp =
78⁰F
CFD Analysis – Mid deck On-Orbit
•
Note: Red is temp at or above 95 F, Max temp was 112 F
7/29/2009
David Gillis, AsMA Annual Meeting 2009
CFD Graphics Courtesy of
Boeing & Chang Son,
PhD
Follow-on Analysis – Mid deck CFD
Wheels on Deck
Graphics Courtesy of Boeing &
Chang Son, PhD
7/29/2009
David Gillis, AsMA Annual Meeting 2009
CFD Boeing and Chang Son, PhD
17
L. H. Kuznetz
Analysis of Mid deck crew core temperatures by Grant Bue suggested
exeedences, particularly if orbital wave-offs were required by adverse
weather or cross-winds, etc. The Orbiter Program Office agreed CFD
analysis was necessary
Forecast STS-326 Mid deck crew core temperatures
Core Temperature for TD-1.5
Core Temperature for TD-1.0
@ TD
@ Egress
@ TD
@Egress
0 Orb
Waveoff
99.0
99.7
98.8
99.5
1 Orb
Waveoff
99.7
100.4
99.5
100.3
2 Orb
Waveoff
100.4
101.1
100.4
101.1
**Results did not take reduced middeck flow bulk analysis into account.
7/29/2009
David Gillis, AsMA Annual Meeting 2009
19
Thermoregulatory Aspects
Hot Environments
Risk Factors for Heat Illness
•
•
•
•
•
•
•
•
•
High Humidity
Cardiovascular disease
Dehydration
Electrolyte imbalance
Non-specific illnesses
Non-permeable clothing
Skin rash
Advanced Age
Poor Physical fitness level
Heat Stroke
Failure of Thermoregulation
•
•
•
•
•
•
•
Elevated core temperature
Hypothalamic dysfunction
Weakness, headache, nausea & vomiting
Ataxia, disorientation, unconsciousness
Variable sweat state
Increased risk if ‘heat intolerant’
Heat intolerant prevalence about 12%
Heat Stroke
Failure of Thermoregulation
• Multiple organ system damage, g.i. and renal
• CNS dysfunction leading to seizure and /or
death
• A true medical emergency
• Substantial protection from heat stroke by
previously induced thermotolerance
Thermal Acclimatization
(Thermotolerance)
• Requires 10-14 days to maximal level
• Earlier onset of sweating and at lower body
temperature
• Increase in hourly sweat volume
• Lower salt content of sweat
• Expanded plasma volume
• Increased tolerance to heat and less thermal stress
• Reduced heart rate response
• Lower core temperature for a given exposure
• Expression of heat shock proteins, including HSP70
Heart Rate
HI
HT
Minutes
Moran, Berchoer, Heled et al; Heat
intolerance: Does gene
transcription contribute? J Appl
Physiol 100:1370-1376 2000
HI
HT
Rectal Temp
HI
HT
Physiological Strain Index
Moran, Berchoer, Heled et al; Heat intolerance: does gene transcription
contribute? J Appl Physiol 100:1370-1376 2000
HI
TRE - TSK
HT
HT
TRE - TSK
Heat Intolerant Humans have
Reduced cardiovascular response
and reduced cellular Heat Shock
Response
TRE - TSK
HI
Molecular events of the heat shock response
The heat shock response
was first observed in 1962
in the fruit fly (Ritossa F, Exp Cell
Res 1964, Science 1964)
Induces reprogramming of
gene expression and
chromatin remodeling
Triggering signals include
heat, oxidative stress,
cytotoxic drugs, heavy
metals, starvation
Cohen & Meselson, PNAS 1984
Chromosome puffing is evidence of heat
shock response in Drosophila sp
Heat Shock Proteins (HSPs)
•Highly conserved across species
•Present in both prokaryotic and eukaryotic organisms
bacteria
yeast
vertebrates
C. elegans
Drosophila
invertebrates
Homo sapiens
(Images from wikipedia.org)
Heat Shock Proteins (contd.)
• Classified
according to size
(Ex: HSP90)
90 kDa
70 kDa
cluster
40 kDa
SDS-PAGE in
heat-shocked
Drosophila
spp lysates
27 kDa
cluster
10 kDa
Sinibaldi & Storti, 1982
•Constitutive or
inducible
a) HSP70 is induced by 15 min heat
shock in the rat cerebral cortex
b) HSP27 is also induced in the cortex
but is constitutively expressed in the
brain stem
Franklin et al, 2005
Heat Shock Proteins (contd.)
• Intracellular
cytoprotective and
antiapoptotic functions:
“chaperones”
• Participate in protein
folding and assembly,
preserving protein
functionality
• Present also on the cell
surface (receptor
function) and
extracellular fluids
(immunomodulator and
inflammation functions)
ĸ
Schmitt et al, 2007
Protein Folding in
the Endoplasmic
reticulum (ER)
mRNA
Cytoplasm
ER Lumen
glycosylation
folding
Di-S bridge
Molecular Expressions TM
Cytoplasm
Proteasome
degradation
Export
Adapted from Christis et al, FEBS J 2008
Degradation of Misfolded Proteins in the Proteasome
Hochstrasser, Nature 2009
Clinically relevant diseases associated with misfolded protein
aggregates
Disease
Protein
Aggregate
Molecular
transmissibility Infection cycle
Huntington’s
Disease
Lewy’s
Yes
No
Alzheimer’s
Amyloid-β
Yes
Unknown
Parkinson’s
α-Synuclein
Host-to-graft
Unknown
AA
Amyloidosis
Amyloid A
Yes
Possible
Extracted from Aguzzi A., Nature 2009
Kregel, K. C. J Appl Physiol 92: 2,177-2,186 2002
34
Heat Shock Factor 1 (HSF1) and HSP gene transcription
Deacetylation by
Sirtuins
3
3
Tonkiss & Calderwood, Int J Hyperthermia 2005
Sirtuin deacetylation and ADPribosylation reactions
Haigis & Guarente, Genes Dev 2006
Stress-Inducible regulation of HSF1
by the deacetylase SIRT1
Westerheide et al, Science 2009
SIRT1 activation or upregulation
augments HSF1 binding to HSP70
promoter and heat shock
response
Conversely, HSF1 knock-down
attenuates the heat response
Cellular Pathways Modulated by Sirtuin Activation
resveratrol
celastrol
SRTxxxx
Calabrese et al, Neurochem Res 2008
Sirtuins promote DNA stability
Rodgers, Cell Metab 2006
Oberdoerffer et al, Cell 2008
Variability in heat stress response and tolerance can be measured
in blood parameters
HSP70 protein expression at 3 and 4 h
after initiation of heat
shock (or control conditions) in WBC
obtained from 5 normal
human volunteers (ELISA)
Sonna et al, J Appl Phys 2002
qRT-PCR of HSF-1 mRNA in
lymphocytes of tolerant (T) and heat
intolerant (HI) subjects after heat
tolerance test and recovery of 1 h
Moran et al, J Appl Phys 2006
Work flow for proposed human thermal studies
Cognitive (PVT) and
physiological assessment
(core temp, etc)
Whole blood
Plasma
WBC
Blood collection and processing
DNA, RNA, protein banking
DNA :
Methylation studies
RNA: genomic
and miRNA
profiling
Pathway Analysis
•Functional annotation
•miRNA target predictions
•Genetic networks
Protein:
global plasma proteomics
Sirtuin and AMPK activity
Translational studies
•Biomarker discovery and validation
•Pathophysiologic mechanisms
•Countermeasure leads
Assessing Cognitive Performance During Thermal Stress
Engineering Psycho-physiology
– Thermal Physiological Stress
• Cardiovascular
• Musculo-skeletal
– Thermal Nervous System Stress
• Autonomic Nervous System Function
• Cognitive Stress (CNS)
– Thermal Cellular Stress
• Heat Intolerance and Acclimation effects
• Advanced Age
• ? Female Gender
42
Assessing Cognitive Performance During Thermal Stress
Neurodegenerative symptoms
Thermal Stress symptoms
Memory Loss
Sensory Discomfort-thermal
Mild cognitive impairment
Cognitive Impairment
Moderate cognitive impairment
Alternation in consciousness &
functional impairment
Severe cognitive impairment,
functional impairments
Dizziness and/or vomiting,
postural collapse
CNS death
Seizure
Unconsciousness
Permanent neuronal injury
CNS Death
Common thread: rate of misfolding proteins
exceeds chaperone protein capacity to maintain
cell function
Average # Mistakes per Hour
NASA 3000 Man-Systems Integration Standards, Revision B, July 1995
Morse
keying
errors per
hour
20 errors/hr
5 errors/hr
3rd Hour
A
The referenced
Roth, 1968 is
actually
Mackworth, 1946,
for the British
Railway (See Roth,
1968)
1st Hour
Where does Roth fit? At
A or B, or between A and
B or after B?
A
B
A
Koroshetz & Bonventre: Heat shock response in the central nervous
system, Experientia 50:11-12, 1085-1091 (1994)
• Heat shock response induced in nervous
tissue by ischemic brain injury, trauma,
thermal stress and status epilepticus
•A
short thermal stress markedly induced
expression of heat shock protein mRNA while
general protein synthesis was depressed by the
heat shock
•Heat shock protein synthesis was necessary
for the neuroprotective effect
% Non-viable cells without Heat Shock
Koroshetz & Bonventre: Heat shock response in the central nervous
system, Experientia 50:11-12, 1085-1091 (1994)
Figure 1C:
Neuroprotection in
neuronal cultures
induced by heat
shock response
% Non-viable cells after Heat Shock
Lim & Dinges, Sleep Deprivation and Vigilant Attention, Ann. NY Acad
Sci 1129:305-322 (2008)
Lim & Dinges, Sleep Deprivation and Vigilant Attention, Ann. NY Acad
Sci 1129:305-322 (2008)
Lapse duration correlation with frequency of lapses after
sleep deprivation- 0.7 5 sec.
Lim & Dinges, Sleep Deprivation and Vigilant Attention,
Ann. NY Acad Sci 1129:305-322 (2008)
Thermal distraction lapses from heat discomfort or impairment
with core temperature function on X-axis
50
Lim & Dinges, Sleep Deprivation and Vigilant Attention,
Ann. NY Acad Sci 1129:305-322 (2008)
Repeated testing lapses from heat discomfort or impairment
with multiple exposures and core temperature functions on Xaxis
51
Lim & Dinges, Sleep Deprivation and Vigilant Attention,
Ann. NY Acad Sci 1129:305-322 (2008)
Cumulative lapses from heat discomfort or impairment with
cutoff for maximum discriminability between thermal exposures
52
Strangman, Zhang & Zeffiro. Near-infrared neuroimaging with NinPy;
Frontiers in Neuroinformatics, May 2009 3:1-13
Near Infra-red Brain Imaging and Spectroscopy
Near-infrared imaging and spectroscopy offers noninvasive assessment of cerebral oxygen supply and
blood volume and detection of some alterations in
brain functioning. The technology is lightweight,
non-invasive and relatively inexpensive.
There are possibly correlations between NIR signals
and brain functional changes associated with
thermally-induced cognitive alterations
53
Mobile NIN Devices
OpticHolter 2a
LED source
Photodiodes
3-axis
Accelerometer
ECG/
Resp
• Self-contained
• Weighs 350g
• Low-power
• Sensitive to
cerebral blood
oxygen/volume
G. Strangman
OpticHolter 2a & Physiology
Baseline Physiology
Vasomotor
Cardiac
Respiratory
Valsalva Maneuvers
Head Up/Down Tilt
G. Strangman
Hemodynamics vs. Gravity Load
Martian
Lunar
Zero
Near Infrared Neuroimaging
Near-infrared photon propagation in the head (Monte Carlo simulations)
Src
1.0 cm
Det
2.5 cm
4.0 cm
Image reconstruction process using near-infrared data
Projection or
tomographic
reconstruction
Map of changes in oxyhemoglobin
Strangman et al. (in press) Frontiers in Neuroinformatics
G. Strangman
Lim & Dinges, Sleep Deprivation and Vigilant Attention,
Ann. NY Acad Sci 1129:305-322 (2008)
Expectations of Cognitive Testing:
•No acclimatization during low thermal exposures
•Poor HSP response in cases of thermal intolerance
•In studies resulting in acclimatization we will see:
• elevated threshold for discomfort and cognitive
impairment
• elevated basal serum level of HSP proteins
• attenuated further HSP response to similar or
even more stressful thermal exposures
• earlier onset of sweating and greater sweat
volumes and lower core temperatures
•Reduced risk of thermal exhaustion and/or heat
stroke (no such exposures planned)
58
A Broad Array of Cytoprotection Mechanisms
for the Defense of Cells, Organs and the
Organism Against Environmental Stresses and
Diseases of Ageing Have Been Demonstrated
Secondary to Three Mechanisms: Heat Shock,
Calorie Restriction and Sirtuin Activation,
With Many Common Expression Pathways
59
Lee et al, Heat shock protein 72 overexpression protects against
hyperthermia, circulatory shock, and cerebral ischemia during
heatstroke, J Appl Physiol 100: 2073-2082, 2006
Normal
(-) HSP72
(+) HSP72
TA
Ambient Temp
HR
Heart Rate
TCO
Colon Temp
Striatal Blood Flow
TSBF
MAP Mean Art. Pressure
SPO2
Striatal PO2
TA
TCO
69 Minute Exposure
HR
TSBF
SPO2
MAP
Gill and Sleivert, Effect of daily versus intermittent exposure on heat acclimation, Aviat Space Environ
Med 2001; 72:385-390
Core Temperature vs Acclimation Day
10 30-Minute heat exposures,
38°C, 70% relative humidity
♦ = Intermittent
◊ = Consecutive
+ = sig dif from day 1
# = sig dif from day 5
* = sig dif between groups; p<0.05
Gill and Sleivert, Effect of daily versus intermittent exposure on heat acclimation, Aviat Space Environ
Med 2001; 72:385-390
Heart Rate vs Acclimation Day
10 30-Minute heat exposures,
38°C, 70% relative humidity
♦ = Intermittent
◊ = Consecutive
+ = sig dif from day 1
# = sig dif from day 5
* = sig dif between groups; p<0.05
Gill and Sleivert, Effect of daily versus intermittent exposure on heat
acclimation, Aviat Space Environ Med 2001; 72:385-390
Rating of Perceived Exertion (RPE) vs
Acclimation Day
10 30-Minute heat exposures, 38°C,
70% relative humidity
♦ = Intermittent
◊ = Consecutive
+ = sig dif from day 1
* = sig dif between groups; p<0.05
Gill and Sleivert, Effect of daily versus intermittent exposure on heat acclimation, Aviat Space Environ
Med 2001; 72:385-390
Skin Temperatures vs Acclimation Day
10 30-Minute heat exposures, 38°C, 70%
relative humidity
♦ = Intermittent
◊ = Consecutive
+ = sig dif from day 1
* = sig dif between groups; p<0.05
Gill and Sleivert, Effect of daily versus intermittent exposure on heat acclimation, Aviat Space Environ
Med 2001; 72:385-390
The theoretical accumulation and decay of heat acclimation
using intermittent vs. consecutive day acclimation protocols.
* = Acclimation Session
SIRT1
SIRT2
SIRT3
1
747
54
98 122 127 128 134
1
389
65
84
126
45
62
261
104
1 7 13 17 21
382 399
1
244
280
345 349
147 170 171 187
145
82
165
143 147
195 200
363
498
221 224
228 229 232 248 256 259
169 172
371 374 395 398
340
280 283
220 223
314
SIRT4
1
41
58
77
140 144 166169
207 212
275 276
309 310
SIRT5
SIRT6
SIRT7
1
345 355
1
400
8
35
52
74
71
113 117
90
107
141 144
126
166 177
167 171
274 287
195 198
225 228 331
Figure 4: Domain Architecture of
Human Sirtuin Family of Class III
NAD+ Dependent Histone
Deacetylases
Deacetylase Domain
Proline Rich Region
Nucleotide Phosphate Binding
Domain
Metal Ion Binding Domain
Loss of Function Mutagenesis
Sites
Arginine Rich Region
(Figures are adapted from UniProt
Universal Protein Resource Database.
Constructs not drawn to scale)
Alanine Rich Region
Glutamic Acid Rich Region
Aspartic Acid Rich Region
Mitochondrial Targeting
Sequence Residues
7/29/2009
66
Heat Shock and Sirtuin Activation Benefits
• Metabolic
– Increases mitochondrial biogenesis
– Lean habitus
– SIRT1
• positively regulates glucose-stimulated insulin secretion in
pancreatic β-cells in mice
• Promotes efficient energy generation
• Controls liver gluconeogenesis
• Activated by the polyphenol resveratrol
– SIRT3
• expressed in brown adipose tissue & induced by cold
exposure
• Regulates mitochondrial functions
– SIRT7
– regulates cell growth and metabolism in response to changing
metabolic conditions
67
Heat Shock and Sirtuin Activation Benefits
• Gastro-intestinal
• Restraint and water immersion stress rapidly activated HSF1 in
rat gastric mucosa < 15 min and induced HSP70 mRNA
expression and protein accumulation.
• HSP70 mRNA expression correlated with severity of mucosal
lesions
• Therapeutic agent inducers of HSP70 may benefit the
prevention and treatment of stress ulcer
• Guinea-pig fundal glands displayed a typical heat shock
response after exposure to elevated temperature, ethanol or
hydrogen peroxide, developing resistance to these insults
68
Heat Shock and Sirtuin Activation Benefits
• Wound Healing
– He-Ne laser irradiation to injured muscles in rats
improved muscle regeneration 2X when administered on
alternate days
– Ga-Al-As infrared laser ↓ muscle degeneration and
↑ cytoprotective HSP70i content
– Phototherapy reduced scar tissue after induction of
myocardial infarction by 50-70%
– Associated with improved ventricular function and
elevation of HSP71i and ATP in the infarcted zone
69
Heat Shock and Sirtuin Activation Benefits
– Genomic
• Stabilizes the genome through increased DNA
repair or silencing
• Knockout mice display premature aging, ↓
bone density, die < 4 weeks of age, genomic
instability
• Reduces oxidative stress
• Anti-tumorigenesis
• Extends replicative lifespan in yeast, C. elegans
worm, Drosophila fruit fly, and mice
70
Heat Shock and Sirtuin Activation Benefits
– Cardiovascular
– Transgenic mice over-expressing HSP70 had
enhanced contractile & metabolic myocardial
recover post-ischemia.
• HSP70 in cardiac muscle is upregulated in male
rats after exercise >24m/min and is primarily
intensity dependent (exceeding the lactate
threshold) rather than duration dependent.
• With heart rate >90% of maximum, HSP70 ↑22X
control
71
Heat Shock and Sirtuin Activation Benefits
Cardiovascular
Potente & Dimmeler, Emerging roles of SIRT1 in vascular endothelial homeostasis, Cell Cycle
7:14, 2117-2122, 15 July 2008
Heat Shock and Sirtuin Activation Benefits
Cardiovascular
Potente & Dimmeler, Emerging roles of SIRT1 in vascular endothelial homeostasis, Cell Cycle
7:14, 2117-2122, 15 July 2008
•In endothelial cells, SIRT1 :
•modulates the transcriptional activity of Foxo1 and p53
•activates the enzymatic activity of endothelial nitric oxide
synthase (eNOS).
•regulates cholesterol homeostasis by deacetylating the
nuclear factor LXR in hepatocytes.
•improves insulin sensitivity under insulin resistant
conditions.
Potente & Dimmeler, Emerging roles of SIRT1 in vascular endothelial homeostasis, Cell Cycle
7:14, 2117-2122, 15 July 2008
Cardiovascular
Figure 1.
Signaling networks of
SIRT1 involved in the
maintenance of vascular
homeostasis
Heat Shock and Sirtuin Activation Benefits
– Nervous System
• Neuroprotective
–Protects against neurodegenerative
pathology in mouse models for Alzheimer’s
Disease and Parkinson’s Disease
–Axonal protection from Polyglutamine
toxicity in mammals
–Over-expression spares β-amyloid-induced
death of microglia
75
Heat Shock and Sirtuin Activation Benefits
– Lifespan extension
SIRT2 :
• I up-regulated by calorie restriction
• extends lifespan in yeast, C. elegans worm,
Drosophila fruit fly, and mice
SIRT3-5 may regulate metabolism, oxidative
stress response and, ultimately, mammalian
aging
76
Longevity
Rhesus monkeys, left to right, Canto, 27, on a restricted diet, and Owen,
29, a control subject on an unrestricted diet, are pictured at the
Wisconsin National Primate Research Center. The two are among the
oldest surviving subjects in a pioneering long-term study of the links
between diet and aging in Rhesus macaque monkeys, which have an
average life span of about 27 years in captivity. Photo: Jeff Miller
77
Heat Shock and Sirtuin Activation Benefits
Dodd, Hain & Judge: Hsp70 prevents disuse muscle atrophy in
senescent rats; Biogerontology, Epub, Dec 2008
Muscle Function
•After 6 days of immobilization, muscle diameter &
Hsp70 ↓20% in senescent control rats
•Atrophy was prevented in fibers over-expressing Hsp70.
•NF-ĸB ↑ 3X in young rats, 5X in senescent rats after 6
days
• Atrophy prevented by HSP70 over-expression.
•HSP70 over-expression prevents disuse atrophy in
senescent rats, possibly through suppression of the NFĸB pathway.
78
Heat Shock and Sirtuin Activation Benefits
Ogata, Oishi, Higashida et al; Prolonged exercise training induces long term enhancement of
HSP70 expression in rat plantaris muscle; Am J Physiol Regulatory Integrative Comp Physiol
296:1557-1563, Feb 2009
Muscle Function
• Mature male rats had either a single bout of acute, intermittent
treadmill running at 30m/min, 5 min, & 4.5⁰ grade,
or
•prolonged treadmill running, 15-40 m/min, 5 min & 4.5⁰ grade.
•HSP70 levels were ↑@ 6 & 24 h after acute exercise, normal afte 2 days.
• Prolonged training had prolonged enhancement: 4.5X ↑ after 2 days
and maintained ≥14 days after training ended. This increase occurred
without ↑ in transcription of HSP70 mRNA.
• Prolonged training evokes a long-term enhancement of HSP70
expression without change at the mRNA level in skeletal muscle
79
Ogata, Oishi, Higashida et al; Prolonged exercise training induces long term enhancement of
HSP70 expression in rat plantaris muscle; Am J Physiol Regulatory Integrative Comp Physiol
296:1557-1563, Feb 2009
Muscle Protection- HSP70
The acquisition of muscle tolerance to contractioninduced muscle damage through exercise training
appears to be partially associated with molecular
mechanisms including chaperone functions in addition to
neuromuscular and morphological adaptations.
Prolonged exercise training increases molecular
chaperone proteins in skeletal muscle, including HSP25,
HSP70 and glucose-regulated protein GRP78.
The chronic enhancement of HSP70 potentially plays an
important role in maintaining cellular homeostasis in
skeletal muscles.
80
Heat Shock and Sirtuin Activation Benefits
Ogata, Oishi, Higashida et al; Prolonged exercise training induces long term
enhancement of HSP70 expression in rat plantaris muscle; Am J Physiol
Regulatory Integrative Comp Physiol 296:1557-1563, Feb 2009
Single acute exercise
Prolonged training, 8 weeks
Fig. 2A Changes in HSP70 with acute and prolonged exercise.
Plantaris muscle weight maintained.
Heat Shock and Sirtuin Activation Benefits
Ogata, Oishi, Higashida et al; Prolonged exercise training induces long term
enhancement of HSP70 expression in rat plantaris muscle; Am J Physiol
Regulatory Integrative Comp Physiol 296:1557-1563, Feb 2009
Fig. 3 Plantaris muscle/body weight ratio and
HSP70 content in muscle during detraining periods
Naito, Powers, Demirel et al; Heat stress attenuates skeletal muscle atrophy in
hindlimb-unweighted rats. J Appl Physiol 88:359-363 2000
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Naito, Powers, Demirel et al; Heat stress attenuates skeletal muscle atrophy in
hindlimb-unweighted rats. J Appl Physiol 88:359-363 2000
8 days of hindlimb unweighting reduced Soleus muscle weight 25%.
Preceding this with heat shock reduced Soleus muscle weight loss 17%
Muscle Weight -mg
% HSP72 levels
Fig 2 HSP72 Attenuation of muscle loss with 8 days of hindlimb unweighting
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Allen, Bandstra, Harrison et al: Effects of spaceflight on murine skeletal
muscle gene expression. J Appl Physiol 2009 106(2):582-595
Studied gastrocnemius in mice during an 11-day, 19 h
Shuttle flight, STS-108 with ground-based hindlimb
unloaded controls
272 mRNAs were significantly altered by spaceflight, with
similar responses to the hindlimb unloaded controls
Spaceflight resulted in significantly modified mRNA
expression in genes associated with muscle growth and
fiber type
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Muscle Protection
Marzetti et al; Sarcopenia of aging: underlying cellular mechanisms and
protection by calorie restriction. Biofactors. 2009 Jan-Feb;35(1):28-35
-- Sarcopenia of aging, the loss of muscle mass and
function, is a common feature of aging and impacts on
individual health and quality of life.
-- Caused by: mitochondrial dysfunction, altered
apoptotic and autophagic signaling, and trace metal
dyshomeostasis.
-- Calorie restriction (CR) without malnutrition has been
shown to ameliorate the age-related loss of muscle mass
in a variety a species.
-- Moderate CR may promote muscle mitochondrial
biogenesis in middle-aged human subjects.
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Paroo, Dipchand & Noble: Estrogen attenuates postexercise HSP70 expression
in skeletal muscle; Am J Physiol Cell Physiol 2001 282:C245-C251
Muscle Protection- HSP70
• Post-exercise HSP70 induction in skeletal muscle is
greater in male than female rats at both the protein
and mRNA level (P=0.005)
• Placebo-treated ovariectomized rats have greater
HSP70 response to exercise than those treated with
estrogen (P=0.015 for protein and P=0.019 for
mRNA).
• Compounds structurally related to 17β-estradiol
but which do not activate the estrogen receptor, also
attenuate the HSP70 induction with exercise
(P=0.01).
• There is gender specificity with regards to the
HSP70 induction response.
Paroo, Dipchand & Noble: Estrogen attenuates postexercise HSP70 expression
in skeletal muscle; Am J Physiol Cell Physiol 2001 282:C245-C251
Muscle Protection- HSP70
Estrogen attenuates HSP70 and mRNA response to exercise
Paroo, Dipchand & Noble: Estrogen attenuates postexercise HSP70 expression
in skeletal muscle; Am J Physiol Cell Physiol 2001 282:C245-C251
Muscle Protection- HSP70
Estrogen-mediated attenuation of muscle membrane
damage after exercise
Blatteau, Gempp, Balestra et al: Predive Sauna and Venous Gas Bubbles Upon
Decompression from 400kPa. Av Sp & Environ Med 79(12):100-1105 Dec
2008
Decompression Illness Protection
• 16 Divers compressed in chamber to 400kPa ( 30
fmsw) for 25 min and decompressed at 100 kPa/min
with 4 min stop at 130 kPa.
• 2 dives, 5 days apart, one with and one without a
pre-dive sauna session for 30 min at 65⁰C ending 1 hr
prior to the dive
• Precordial Doppler at 20, 40, and 60 min after
surfacing, at rest, and after flexions. Bubble
formation in the post-sauna group was reduced 27%
(at rest) and 35% after flexions.
• Plasma HSP70 was significantly ↑ 2 hr after sauna
completion, significantly decreasing circulating
bubbles after the dive.
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Endothelial Biomedicine by Aird, W. C., Cambridge University Press, 2007
ISBN 0521853761, 1856 pages
Cardiovascular
Decompression Illness Protection
• Rats exposed @ 42⁰C 24 hr prior to a dive reduced
mortality by 50% while HSP 70 ↑, but not HSP90 or
endothelial NO synthase (eNOS) and bubble formation
was not affected ( A. O. Brubakk, unpublished
observation
• HSPs may represent a link between flow-mediated
induction of shear stress and NO.
• Exercise and hyperbaric oxygen can act as a
preconditioning regimen, protecting against injury,
probably through regulation of HSP and NO
• HSP90 is important modulator of eNOS production…
and may be of importance in preventing injury caused
by increased oxygen tension
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Preventing Degenerative Diseases of Ageing
92
Proteotoxic stress and inducible chaperone networks in
neurodegenerative disease and aging
Genes Dev. 2008 22: 1427-1438
Richard I. Morimoto
Department of Biochemistry, Molecular Biology, and Cell Biology, Rice Institute for
Biomedical Research, Northwestern University, Evanston, Illinois 60208, USA
7/29/2009
93
Neurodegenerative Disease Protection
.We
crossbred SCA1 mice with mice over-expressing
a molecular chaperone (inducible HSP70 or iHSP70).
We found that high levels of HSP70 did indeed afford
protection against neurodegeneration.
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Small molecule activators of SIRT1 as therapeutics for the treatment of type 2 diabetes, Milne, J.C., Lambert,
P.D. et al, Nature 450 29Nov2007
Other Small Molecule Activators of the Heat Shock Response
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Summary
• Thermal environmental effects are complex
• Many physiological stresses can be reduced by acclimation
• The cellular responses to ‘heat shock’ modify the phenotype
and provide varied, robust and beneficial adaptations
• Thermally induced cognitive impairment and cellular effects
of nominal and off-nominal potential exposures are important
aspects of mission assurance and crew safety
• Thermal testing of various space suit ensembles provides a
golden opportunity to conduct important human medical
information to advance the health and safety of crew during
exploration missions
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Summary
• Multiple small molecules, including resveratrol, celestrol and
other newly synthesized molecules stimulate the sirtuin protein
system, producing cellular adaptations mimicking calorie
restriction and the heat shock response.
• These agents are currently undergoing human tests for use in
treating degenerative diseases of ageing, including
cardiovascular disease, metabolic syndrome and type II
diabetes, muscle disorders and neurodegenerative diseases.
• These agents may offer the additional benefits of heat shock
in a convenient dosing form with broad cytoprotection,
including reduction of muscle and bone loss in reduced gravity
and substantial increased stress tolerance of multiple organs to
hypoxia, thermal stress, oxidative stress, infection, trauma,
acute lung injury, ischemia and re-perfusion injury, radiation,
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tumors, heavy metals and ageing
Summary
• An early benefit may be substantial increase in the threshold
for cognitive impairment secondary to thermal stress, utilizing
the oral therapeutic agent rather than a conditioning thermal
exposure, and stimulating the attendant broad additional
protections at the same time.
• Very active research and clinical trials are currently underway
and advances are reported weekly. Ancillary benefits for
exploration should be actively pursued as they become
available as expected.
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Thank You
Questions?
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