Implications of Telomere
Maintenance in Aging-Related
Disease Progression
Fundacion Fernandez-Cruz, Madrid
October 26, 2015
Elizabeth Blackburn, PhD
University of California San Francisco
Telomeres: what are they?
…and why do we care?
Impacts of unbalanced
telomere maintenance in humans
Influences on telomere maintenance in
humans
NON-GENETIC GENETICEnvironmental Life events/behavior
First, a framework……
Aging-related diseasesoften go hand-in-hand (co-morbidity):
Poor immune function Diabetes Cardiovascular disease Cancers Mental/cognitive disorders/depression
Aging-related diseasesoften go hand-in-hand (co-morbidity):
Poor immune function Diabetes Cardiovascular disease Cancers Mental/cognitive disorders/depression
“The World Health Organization (WHO) projects that both
cardiovascular disease (CVD) and major depressive
disorder (MDD) generate the greatest loss of ‘disability-
adjusted life years’ in 2030.”
van Marwijk BMC Cardiovascular Disorders 2015, 15:40
Telomeres: what are they?
…and why do we care?
Impacts of unbalanced telomere maintenance
in humans
Influences on telomere maintenance in
humans
Telomeres
cap ends of
chromosomes
3’
Telomeric DNA Structure
5’3’ 5’
Telomere
Chromosome
Simple repeated DNA
sequence
Blackburn and Gall, 1978
… and in yeast too
Blackburn and Szostak, 1982;
Shampay, Szostak and Blackburn 1984
Tetrahymena thermophila
- “Pond scum”
The Telomere
– the protective cap at every chromosome end
TTAGGGTTAGGGTTAGGGTTAGGGTTAGG
GAATCCCAATCCC
Protective proteins
ce
ll d
ivis
ion
s
Eventual senescence
Predicted, if DNA replication alone acts on DNA:
Loss of DNA from the chromosome end
Watson, 1972, Olovnikov, 1971
T TG T GTGG G GG GT GTGG G
DISCOVERY OF TELOMERASE
Tetrahymena cell extract
Mg++
dGTP + TTP
5’ 3’ OH
SYNTHETIC TELOMERE IN TEST TUBE
T TG T GTGG G GG GT GTGG G G T GTGG G G G
Greider and Blackburn, 1985
Carol Greider,
UC Berkeley
ca.1985
GGGGTTGGGGTTGGGGTTGGGGTTGCCCCAACCC AACCCCAAC
5'
3'
The solution to telomere attrition
Telomerase: a
telomere-synthesizing reverse transcriptase
ChromosomeTerminus
GGGTTG
protein RNA
Greider and Blackburn, 1985, 1987, 1989
5'3'
cell d
ivis
ion
s
Cells keep dividing
Most human cancers
With sufficient
telomerase:
Addition and shortening
stay balanced
ce
ll d
ivis
ion
s
After a delaySTOP
Human cells: insufficient telomerase
ce
ll d
ivis
ion
s
Human cells: insufficient telomerase
Senescence
Cell malfunctions- Mitochondrial malfunction
- pro-inflammatory, tumorigenic factors
Genomic instability
STOP
mitochondria
TelomereUncapped Telomere!
Telomere damage:
A Vicious Cycle
http://omx.hms.harvard.edu/ Cell Image:
Harvard Medical School OMX SIM microscope
Secreted
Inflammatory
factors
DNA
http://omx.hms.harvard.edu/
Telomeric
repeat
tracts
gradually
shorten
over human
lifetimes
Many normal human cells have limiting or no
telomerase and their telomeres shorten with age
Senescence Death ?
WHAT CAN SAVE THE CELLS? Telomerase action:
- Active: stem cells, germ cell lineages
- Low/none: many normal adult cell types
Genetic
anticipationChange in
disease type
Pulm. Fibrosis
Aplastic anemia/Dyskeratosis
congenita
Unique genetics of autosomal dominant
(haploinsufficiency) telomere syndromesRepeated
Telomeric DNA
Sequence Mutant hTR or
hTERT gene
Unique genetics of autosomal dominant
(haploinsufficiency) telomere syndromesRepeated
Telomeric DNA
Sequence Mutant hTR or
hTERT gene
WT*
WT*: Telomere length is NOT
reset/restored in the next
generation, despite restoring
WT genotype
WT * Inherited telomere shortness ALONE causes disease
…and why do we care?
Impacts of unbalanced telomere maintenance
in humans
NON-GENETIC GENETICEnvironmental Life events/behavior
Telomere
Attrition
Risks for aging-related diseases- and mortality
Poor immune function Cancers Cardiovascular disease Diabetes Mental/cognitive disorders/depression
From much research we now know:
Telomeric DNA Structure
Telomere
Chromosome
Simple repeated DNA
sequence
Measure telomere length- e.g., in 100,000 people
The Kaiser Permanente Research Program
on Genes, Environment, and Health (RPGEH)
GERA cohort– Biospecimens:Genetic (GWAS) and biomarker - TELOMERE LENGTH data - saliva and DNA collected 2008 – 9 N=100,000
– Comprehensive clinical data from KPNC Electronic Medical Records (outpatient, inpatient, laboratory, pharmacy, imaging, pathology)
• Complete since 1995 -- Continuously updated
– Participant survey and interview data
• Sociodemographic factors -- Family history
• Behavior
– Environmental exposure data geographic etc
Environmental exposures
Cathy Schaefer, PhD, Director. Neil Risch Elizabeth Blackburn
Kaiser-Permanente University of California, San Francisco
Age
Re
lati
ve T
elo
me
re L
en
gth
20 30 40 50 60 70 80 90
Cross sectional relationship of mean telomere length
with age: Nicoya Exceptional Longevity Blue Zone vs.
Costa Rica population
Rehkopf et al 2013
Nicoya Blue Zone
Costa Rica
Age
males
females
Re
lati
ve T
elo
me
re L
en
gth
20 30 40 50 60 70 80 90
GERA Cohort
Cross sectional relationship of mean human telomere length
with age: males and females.
Mean saliva Telomere Length (cells in saliva). Error bars are 1 s.e. of mean
Lapham, Kvale et al, 2015.
Schaefer et, Unpublished
GERA cohort: Odds of all-causes mortality
within 3 yrs of telomere measure
(N=100,000; ages 20 - 95)
Telomere length at this time
was measured
(N= 100,000)
Who had died
within the 3 years
since telomere length
measure
(N= ~ 2,500)
2009 2012
Compare to
Mean Baseline Telomere Length
Year
time
Copenhagen study: Odds of all-causes mortality
Mean follow-up time after
leukocyte telomere measure = 7 yrs.
Telomere length at this time
was measured
(N= 64,637)
Who had died
~ 7 years (mean time)
after telomere length
measure
(N= ~ 7,604)Compare to
Mean Baseline Telomere Length
Year 0 = baseline
time
Rode et al, 2015
Copenhagen study
0
200
400
600
800
1000
1200
1400
0 1 2 3 4 5 6 7 8 9 10
Any cancer
Cardiovascular
Death Othercauses
All-causemortality
Raw
Number of
Deaths
(unadjusted)
Numbers of Deaths by Telomere Length Decile (unadjusted)
Rode et al,
2015
Copenhagen
study
Telomere Length decile:
1 = longest 10 = shortest
Leukocyte Telomere Length Independently Predicts All-cause MortalityN = 64,637 (7,604 deaths) (Mean Follow-Up time = 7 years)
Mortality
Hazard
Ratio
Multivariate
Adjusted
Decile 10 = Shortest
telomeres
0.8
0.9
1
1.1
1.2
1.3
1.4
1.5
1 2 3 4 5 6 7 8 9 10
Multivariate-Adjusted All-cause Mortality Hazard Ratios vs. Baseline Leukocyte Telomere Length
HR…
Rode et al, 2015
Copenhagen
study
1 = Reference
Telomere Length
decile;
1 = longest 10 = shortest
Telomerase: Dr. Jekyll AND Mr. Hyde
unlimitedreplicativecapacity
finitereplicativecapacity
telomeraseRb-/ p16-
telomerase /ALTp53-
other changes
Less
Telomerase;
Telomere Shortness
(genetic and observed)
WORSE
CANCER
RISKS
Over-active
telomere
maintenance
(genetic)
eg, Hematological,
squamous cell,
gastrointestinal
eg, brain, melanoma, lung
Supplementary Figure 3. Plot showing effect of telomere score on melanoma risk.
Here the telomere score is divided into quartiles and melanoma case-control status
regressed on the resulting categorical variable with the lowest quartile (by telomere
length) as the baseline.
Effect on melanoma risk of telomere length score
(= Alleles predicting longer telomeres)
Q1 = Shortest
telomeres
Q4 = Longest
telomeres
Mark M. Iles et al. JNCI J Natl Cancer Inst 2014;106:dju267
Forest plot of estimated effect size (with a 95% confidence interval indicated by horizontal
bars) for telomere score (= Alleles predicting longer telomeres) on melanoma risk in nine
geographic regions (and combined result).
Mark M. Iles et al. JNCI J Natl Cancer Inst 2014;106:dju267
Genetic variants associated with longer telomere length
are associated with increased lung cancer risk among
never-smoking women in Asia
Telo. score predicting longer telomere length - higher*lung cancer risk
*Cohort =
Asian women
non-smokers
Less
Telomerase;
Telomere Shortness
(genetic and non-genetic)
WORSE
CANCER
RISKS
Over-active
telomere
maintenance
(genetic)
eg, Hematological,
squamous cell,
gastrointestinal
eg, Melanoma,
brain, lung
Hazard Ratios (with a 95% confidence interval indicated
by horizontal bars): telomere allele scores for all-cancers
mortality risk.
AND - genes that predict longer telomeres
predict higher combined all-cancers mortality risk
Rode et al,
2015
Copenhagen
study
But recall, for cancers, observed longer telomeres
predict less all-cancers mortality
Observed
Longer
telomeres
Lower risk of incident
diseases & MORTALITY
- all-causes & CVD
- combined cancers
Rode et al,
2015
Copenhagen
study
Telomere-
lengthening
common gene
variants
Lower risk of
CAD, CHD,AD
Observed
longer
telomeres
Lower risk of incident
diseases & MORTALITY
- all-causes & CVD
- combined cancers
Codd et al 2013
Zhan et al 2015
JAMA
Neurol.72:1202-
1203
ALZHEIMERS: “shorter TL was causally associated with a higher risk for AD
(odds ratio, 1.36 per SD decrease of TL; 95%CI, 1.12 to 1.67; P = .002).”
Zhan et al 2015
Non-genetic
telomere-
lengthening
influences
Telomere-
lengthening
common gene
variants
Lower risk of
CAD, CHD, AD
GREATER
RISKS
(specific
cancers and
all-cancers
mortality)
Lower risk of incident
diseases & MORTALITY
- all-causes & CVD
- combined cancers
For cancers, it isn’t just longer telomeres that matter
– it’s what made them longer that matters
Observed
longer
telomeres
• For AD and CDV risks, and mortality from CVD:
longer telomeres are good
- regardless of why they are longer.
• For cancer risks and mortality from all cancers combined:
longer telomeres can be good or bad
- it is how the telomeres got longer – genes or non-genetic - that matters.
• For OVERALL TOTAL mortality risk:
longer telomeres, statistically, are good - regardless.
SUMMARY OF
HOW CHROMOSOME ENDS RELATE TO THE END
Telomeres:
why we care -
Impacts of unbalanced telomere maintenance
in humans
Influences on telomere maintenance in
humans
A story from 2500 years ago:
how stress accelerates aging
Wu Zixu: 伍子胥
A story from 2500 years ago:
how stress accelerates aging
- not a recent or new concept
Chronic stress is known to impact on diseases
CHRONIC LIFE STRESS
Disease
Impacte.g.,
cardiovascular
A new connection
CHRONIC LIFE STRESSORS
Disease
impact
STRESS signal
integration and
processing
Cynical hostility level is associated with
telomere shortness in the
UK Whitehall Civil Servants Cohort
Brydon et al, 2011
Low Medium HighCynical Hostility Tertiles
Stressors and Shortened Telomeres in Adults • Perceived stress • Caregiver stress
– mothers of ill child– dementia caregivers
• Major Depression– duration and severity
• Former Domestic Abuse – duration of abuse
• Allostatic (stress) load– Lack of psychosocial resources
• Cumulative exposure to childhood traumas:
– or + adult PTSD
• Less education
Tyrka, 2010; Kiecolt Glaser, 2011;
O’Donovan et al, 2011; Surtees, 2011
Steptoe et al, 2011; Needham et al
2013;
Lapham, Kvale, Risch, Shaefer, Blackburn, unpubl.
Epel et al, 2004;Damjanovic, 2006; O’Donovan, 2011;
Wolkowitz et al, 2011
Simon, 2006; Wolkowitz, 2011; Verhoeven et al, 2013
Humphreys et al, 2011
Epel et al, 2004; Parks et al, 2009; Puterman 2010
Zalli et al et al, 2014
Stressors Shorten Telomeres in Children
• Early severe emotional neglect
– Institutionalized in orphanages
(length of exposure)
• Exposure to violence
• Parental education/socioeconomic status of family
• Living in a high-disorder neighborhood
• Autonomic and adrenocortical reactivity Theall et al 2014
Drury et al 2012
Kroenke et al 2011
Needham et al 2012
Shalev et al 2012
Stressors Shorten Telomeres in Children
Exposures of Mothers to Adverse Conditions during
Pregnancy are Associated with
Shorter Telomeres in the Newborns
- i.e., Transgenerational Effects:
1. Intrauterine: - psychological stress exposure
of the mother
→shorter newborn telomere length
→shorter telomeres in adult offspring too
2. Intrauterine: - folate deficiency of
the motherEntringer, Wadhwa et al, 2011, 2013, 2015
Disease
Impact
Chronic psychological stress
Reduced telomere maintenance
Disease
impact
Disease
Chronic
Stress
Connecting Chronic Psychological Stress,
Telomeres and Disease Impact
?
Mechanisms?
Stress and short telomeres: Possible mechanisms
Stress hormones
Epel et al, 2006
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
Short TL
Long TL
Z s
co
res (
ad
j.)
CortisolEpinephrineNorepinephrine
Cortisol reduces telomerase
in PBMCs and CD4+ cells
O’Donovan et al, 2011
Health ABC Study
Systemic
Inflammatory
factors
Systemic
inflammatory
markers
IL-6
TNF-α
IL-6 + TNF-α
TNF-α + CRP
IL-6 + TNF-α + CRP
Short telomeres
OR (95% CI)1.3 (1.0-1.7)*
1.5 (1.2-1.9)**
1.8 (1.3-2.4)**
1.7 (1.2-2.4)**
1.7 (1.1-2.6)**
Adjusted
for all
covariates
Systemic
Oxidative
Stress
Gazzaniga, unpubl; Effros 2008
Oxidative Stress
Ratio = serum F2-
isoprostanes/
Vitamin C
PB
MC
telo
mere
len
gth
(bp
)
Wolkowitz et al., 2011
WHICH STEPS ARE RATE-LIMITING?
BRAIN
Shorter telomeres
Reduced natural killer cell activity
Lower telomerase activity Glucocorticoid-mediated suppression
of p53 and BRCA1 gene expression
Increased pro-inflammatory cytokines
and oxidative stress
Adapted from: Spiegel, D Br J Health Psychol. 2013
Immunosenescence
Stress and short telomeres: Possible pathways
Dysregulation of diurnal cortisol
Mitochondrial
dysfunction
Shorter leukocyte telomeres = an independent risk factor for cardiovascular disease.
Cumulative
hazard
curves
Willeit P et al. Arterioscler Thromb Vasc Biol 2010;30:1649-1656
Short Telomere Length Predicted CVD
CVD
Vascular
Death
Myocardial
infarction
Stroke
Longest
Mid
Shortest
Baseline Telomere Length by Tertiles
Shorter leukocyte telomeres = an independent risk factor for cardiovascular disease.
Prediction from combination of factors?
An example from cancer patients……
Bladder cancer survival:
Interaction of leukocyte short telomeres
with depression
Depression (long telomeres)
or
Short telomeres (not depression)
or
Neither
or
BOTH
At bladder cancer diagnosis:
Lin J et al CEBP, 2014
Lin J et al CEBP, 2014
Kaplan–Meier survival curves by cross-classification of
depression score CES-D (>16 vs.
At bladder cancer diagnosis
Depression (long telomeres)
OR
Short telomeres (not depression)
OR
Neither
OR
BOTH
ONLY depression OR ONLY short telomeres OR neitherAfter 2 ½ years – Who had died
BOTH depression PLUS short telomeres
After 2 ½ years – Who had died
After 5 years – Who had diedONLY depression OR ONLY short telomeres OR neither
BOTH depression PLUS short telomeres
After 5 years – Who had died
Increasing
telomere
shortnessDepression
Bladder cancer patient
mortality
Lin J et al CEBP, 2014
Depression is related to coronary heart disease, hypertension and stroke
Licinio et al 2002. Mol. Psychiatry 7, 1031-1032
Depression = an independent risk factor for cardiovascular disease.
– depression predicts development of coronary heart disease in otherwise healthy individuals
– increased morbidity and mortality in depressed patients with coronary artery disease
• particularly after acute myocardial infarction
• independent of previous history, thereby implicating depression as a risk factor in the progression of heart disease
Licinio et al 2002. Mol. Psychiatry 7, 1031-1032
Environmental Life events/behaviorNON-GENETIC GENETIC
Telomere
Attrition
Risks for aging-related diseases- and mortality
Poor immune function Cancers Cardiovascular disease Diabetes Mental/cognitive disorders/depression
Telomere attrition: an interacting factor underlying diseases
What influences the right balance for
telomere maintenance in humans?Education.
Resiliency
factors:- Exercise
- Sleep
- Stress-
reduction
Omega-3.
Findings from
multiple
observational
studies
CHRONIC STRESS
Low education
Prenatal stress
Childhood trauma
Smoking
Abuse
Neighborhood disorder
Poor dietary intakes
Interactions with GENETIC FACTORS ?
Proper
telomere
maintenance?
Hu
ma
n h
ea
lth
Chronological age
Just a hope, or a practical approach?
Research Acknowledgements
Recent and current
Blackburn lab UCSF
Collaborating groups
Jue Lin
Kyle Lapham
Josh Cheon
Lynn Fang
Beth Cimini
Francesca Gazzaniga
Kyle Jay
Imke Listerman
Tetsuya Matsuguchi
Dana Smith
Jie Sun
Tanya Williams
Eva Samal
Tracy Chow
UCSF
Elissa Epel
Owen Wolkowitz
Sandy Mellon
Mary Whooley
Neil Risch
Pui Kwok
UCI
Prathik Wadhwa
Sonja Entringer
UCL
Andrew Steptoe
Kaiser Permanente
Cathy Schaefer
- and many more!
Research Acknowledgements
Recent and current
Blackburn lab UCSF
Collaborating groups
Jue Lin
Kyle Lapham
Josh Cheon
Lynn Fang
Beth Cimini
Francesca Gazzaniga
Kyle Jay
Imke Listerman
Tetsuya Matsuguchi
Dana Smith
Jie Sun
Tanya Williams
Eva Samal
Tracy Chow
UCSF
Elissa Epel
Owen Wolkowitz
Sandy Mellon
Mary Whooley
Neil Risch
Pui Kwok
UCI
Prathik Wadhwa
Sonja Entringer
UCL
Andrew Steptoe
Kaiser Permanente
Cathy Schaefer
- and many more!
Jue Lin
The end(s)