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
First, a framework……
NON-GENETIC
Environmental
GENETIC
Life events/behavior
Aging-related diseases
often 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 ‘disabilityadjusted life years’ in 2030.”
van Marwijk BMC Cardiovascular Disorders 2015, 15:40
Aging-related diseases
often go hand-in-hand (co-morbidity):
Poor immune function Diabetes Cardiovascular disease Cancers
Mental/cognitive disorders/depression
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
Tetrahymena thermophila
scum”
Telomere
- “Pond
Chromosome
5’
3’
5’
3’
Telomeric DNA Structure
Simple repeated DNA
sequence
Blackburn and Gall, 1978
… and in yeast too
Blackburn and Szostak, 1982;
Shampay, Szostak and Blackburn 1984
The Telomere
– the protective cap at every chromosome end
TTAGGGTTAGGGTTAGGGTTAGGGTTAGG
AATCCCAATCCC
G
Protective proteins
cell divisions
Predicted, if DNA replication alone acts on DNA:
Loss of DNA from the chromosome end
Eventual senescence
Watson, 1972, Olovnikov, 1971
DISCOVERY OF TELOMERASE
SYNTHETIC TELOMERE IN TEST TUBE
5’ G G G G T T G G G G T T G G G G T T 3’ OH
Tetrahymena cell extract
Mg++
dGTP + TTP
G G G G T T G G G G T T G G G GT T G G G G T T G G
Greider and Blackburn, 1985
Carol Greider,
UC Berkeley
ca.1985
The solution to telomere attrition
Telomerase: a
telomere-synthesizing reverse transcriptase
GGGTTG
GGGGTTGGGGTTGGGGTTGGGGTTG
AACCCCAAC
5'
CCCCAACCC
3'
Chromosome
Terminus
protein
Greider and Blackburn, 1985, 1987, 1989
3'
5'
RNA
cell divisions
With sufficient
telomerase:
Cells keep dividing
Most human cancers
Addition and shortening
stay balanced
cell divisions
Human cells: insufficient telomerase
STOP After a delay
cell divisions
Human cells: insufficient telomerase
STOP
Senescence
Cell malfunctions
-
Mitochondrial malfunction
pro-inflammatory, tumorigenic factors
Genomic instability
Telomere damage:
A Vicious Cycle
UncappedTelomere
Telomere!
Secreted
Inflammatory
factors
mitochondria
DNA
http://omx.hms.harvard.edu/ Cell Image:
Harvard Medical School OMX SIM microscope
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
Unique genetics of autosomal dominant
(haploinsufficiency) telomere syndromes
Repeated
Telomeric DNA
Sequence
Mutant hTR or
hTERT gene
Pulm. Fibrosis
Aplastic anemia/Dyskeratosis
congenita
Genetic
anticipation
Change in
disease type
Unique genetics of autosomal dominant
(haploinsufficiency) telomere syndromes
Repeated
Telomeric DNA
Sequence
Mutant hTR or
hTERT gene
WT*: Telomere length is NOT
reset/restored in the next
generation, despite restoring
WT genotype
WT*
WT * Inherited telomere shortness ALONE causes disease
…and why do we care?
Impacts of unbalanced telomere maintenance
in humans
From much research we now know:
NON-GENETIC
Environmental
GENETIC
Life events/behavior
Telomere
Attrition
Risks for aging-related diseases
- and mortality
Poor immune function Cancers Cardiovascular disease
Mental/cognitive disorders/depression
Diabetes
Measure telomere length
- e.g., in 100,000 people
Telomere
Chromosome
Simple repeated DNA
sequence
Telomeric DNA Structure
–
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.
Kaiser-Permanente
Neil Risch
Elizabeth Blackburn
University of California, San Francisco
Relative Telomere Length
Cross sectional relationship of mean telomere length
with age: Nicoya Exceptional Longevity Blue Zone vs.
Costa Rica population
Nicoya Blue Zone
20
30
40
50
Age
60
70
80
Costa Rica
90
Rehkopf et al 2013
Relative Telomere Length
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
females
males
20
30
GERA Cohort
40
50
60
Age
70
80
90
Lapham, Kvale et al, 2015.
GERA cohort: Odds of all-causes mortality
within 3 yrs of telomere measure
(N=100,000; ages 20 - 95)
Year
2009
2012
time
Telomere length at this time
was measured
(N= 100,000)
Who had died
within the 3 years
since telomere length
measure
(N= ~ 2,500)
Compare to
Mean Baseline Telomere Length
Schaefer et, Unpublished
Copenhagen study: Odds of all-causes mortality
Mean follow-up time after
leukocyte telomere measure = 7 yrs.
Year 0 = baseline
time
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
Rode et al, 2015
Copenhagen study
Numbers of
Deaths by Telomere Length Decile (unadjusted)
1400
1200
Any cancer
1000
Raw
Number of
Deaths
(unadjusted)
Cardiovascular
800
Death Other
causes
All-cause
mortality
600
400
200
0
0
1
2
3
4
5
6
7
8
9
Telomere Length decile:
1 = longest 10 = shortest
10
Rode et al,
2015
Copenhagen
study
Leukocyte Telomere Length Independently Predicts All-cause Mortality
N = 64,637 (7,604 deaths) (Mean Follow-Up time = 7 years)
1.5
Mortality
Hazard
Ratio
Multivariate-Adjusted All-cause Mortality Hazard
Ratios vs. Baseline Leukocyte Telomere Length
1.4
1.3
1.2
HR…
1 = Reference
Decile 10 =
Shortest
telomeres
1.1
1
Multivariate 0.9
Adjusted
0.8
1
2
3
4
5
6
7
8
Telomere Length
decile;
9
10
Rode et al, 2015
Copenhagen
study
Telomerase: Dr. Jekyll AND Mr. Hyde
finite
replicative
capacity
Rb-/ p16p53telomerase /ALT
telomerase
other changes
unlimited
replicative
capacity
Less
Telomerase;
Telomere Shortness
(genetic and observed)
Over-active
telomere
maintenance
(genetic)
WORSE
CANCER
RISKS
eg, Hematological,
squamous cell,
gastrointestinal
eg, brain,
melanoma, lung
Effect on melanoma risk of telomere length score
(= Alleles predicting longer telomeres)
Q1 =
Shortest
telomeres
Q4 =
Longest
telomeres
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.
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
Less
Telomerase;
Telomere Shortness
(genetic and non-genetic)
Over-active
telomere
maintenance
(genetic)
WORSE
CANCER
RISKS
eg, Hematological,
squamous cell,
gastrointestinal
eg, Melanoma,
brain, lung
AND - genes that predict longer telomeres
predict higher combined all-cancers mortality risk
Hazard Ratios (with a 95% confidence interval indicated
by horizontal bars): telomere allele scores for 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
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
Telomerelengthening
common gene
variants
Lower risk of
CAD, CHD,AD
Codd et al 2013
Zhan et al 2015
JAMA
Neurol.72:1202-
Observed
longer
telomeres
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
Non-genetic
telomerelengthening
influences
Telomerelengthening
common gene
variants
GREATER
RISKS
(specific
cancers and
all-cancers
mortality)
Lower risk of
CAD, CHD, AD
Observed
longer
telomeres
Lower risk of incident
diseases & MORTALITY
- all-causes & CVD
- combined cancers
SUMMARY OF
HOW CHROMOSOME ENDS RELATE TO THE END
• 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.
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
- not a recent or new concept
Wu Zixu: 伍子胥
Chronic stress is known to impact on diseases
CHRONIC LIFE STRESS
Disease
Impact
e.g.,
cardiovascular
A new connection
CHRONIC LIFE STRESSORS
STRESS signal
integration and
processing
Disease
impact
Cynical hostility level is associated with
telomere shortness in the
UK Whitehall Civil Servants Cohort
Brydon et al, 2011
Low
Medium
High
Cynical 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:
Epel et al, 2004; Parks et al, 2009; Puterman 2010
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
Zalli et al et al, 2014
Tyrka, 2010; Kiecolt Glaser, 2011;
O’Donovan et al, 2011; Surtees, 2011
– or + adult PTSD
• Less education
Steptoe et al, 2011; Needham et al
2013;
Stressors Shorten Telomeres in Children
Stressors Shorten Telomeres in Children
• Early severe emotional neglect
– Institutionalized in orphanages
(length of exposure)
• Exposure to violence
Drury et al 2012
Shalev et al 2012
• Parental education/socioeconomic status of family
Needham et al 2012
• Living in a high-disorder neighborhood
Theall et al 2014
• Autonomic and adrenocortical reactivity
Kroenke et al 2011
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 mother
Entringer, Wadhwa
et al, 2011, 2013, 2015
Chronic psychological stress
Reduced telomere maintenance
Disease
Impact
Connecting Chronic Psychological Stress,
Telomeres and Disease Impact
Chronic
Stress
?
Disease
impact
Mechanisms?
Stress and short telomeres: Possible mechanisms
Z scores (adj.)
0.6
0.4
0.2
0 Short TL
-0.2
-0.4
Long TL
-0.6
Cortisol
Epinephrine
Norepinephrine
Epel et al, 2006
Cortisol reduces telomerase
in PBMCs and CD4+ cells
Gazzaniga, unpubl; Effros 2008
Systemic
Oxidative
Stress
Systemic
Inflammatory
factors
Systemic
inflammatory
markers
Adjusted
for all
covariates
Short telomeres
OR (95% CI)
1.3
IL-6
1.5
TNF-α
1.8
IL-6 + TNF-α
1.7
TNF-α + CRP
1.7
IL-6 + TNF-α + CRP
(1.0-1.7)*
(1.2-1.9)**
(1.3-2.4)**
(1.2-2.4)**
(1.1-2.6)**
Health ABC Study
O’Donovan et al, 2011
PBMC telomere length
(bp)
Stress hormones
Oxidative Stress
Ratio = serum F2isoprostanes/
Vitamin C
Wolkowitz et al., 2011
Stress and short telomeres: Possible pathways
BRAIN
Dysregulation of diurnal cortisol
Lower telomerase activity
Mitochondrial
dysfunction
Glucocorticoid-mediated suppression
of p53 and BRCA1 gene expression
Shorter telomeres
Immunosenescence
Increased pro-inflammatory cytokines Reduced natural killer cell activity
and oxidative stress
WHICH STEPS ARE RATE-LIMITING?
Adapted from: Spiegel, D Br J Health Psychol. 2013
Shorter leukocyte telomeres = an independent
risk factor for cardiovascular disease.
Short Telomere Length Predicted CVD
Cumulative
hazard
curves
CVD
Stroke
Baseline Telomere
Length by Tertiles
Myocardial
infarction
Shortest
Mid
Vascular
Death
Longest
Willeit P et al. Arterioscler Thromb Vasc Biol 2010;30:1649-1656
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
At bladder cancer diagnosis:
Depression (long telomeres)
or
Short telomeres (not depression)
or
Neither
or
BOTH
Lin J et al CEBP, 2014
Bladder cancer survival: leukocyte short telomere interaction with depression
Kaplan–Meier survival curves by cross-classification of
depression score CES-D (>16 vs. <16) and telomere length
(long vs. short)
N = 441
Adjusted for age, gender, ethnicity,
smoking status, bladder cancer stage,
bladder cancer grade, and treatment
Lin J et al CEBP, 2014
At bladder cancer diagnosis
Depression (long telomeres)
OR
Short telomeres (not depression)
OR
Neither
OR
BOTH
After 2 ½ years – Who had died
ONLY depression OR ONLY short telomeres OR neither
After 2 ½ years – Who had died
BOTH depression PLUS short telomeres
After 5 years – Who had died
ONLY depression OR ONLY short telomeres OR neither
After 5 years – Who had died
BOTH depression PLUS short telomeres
Depression
Increasing
telomere
shortness
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
Telomere attrition: an interacting factor underlying diseases
NON-GENETIC
Environmental
GENETIC
Life events/behavior
Telomere
Attrition
Risks for aging-related diseases
- and mortality
Poor immune function Cancers Cardiovascular disease
Mental/cognitive disorders/depression
Diabetes
What influences the right balance for
telomere maintenance in humans?
Education.
Resiliency
factors:
-
CHRONIC STRESS
Low education
Prenatal stress
Interactions
with
Childhood trauma
Smoking
Abuse
Neighborhood disorder
Poor dietary intakes
Exercise
Sleep
Stressreduction
Omega-3.
GENETIC FACTORS ?
Findings from
multiple
observational
studies
Human health
Just a hope, or a practical approach?
Proper
telomere
maintenance?
Chronological age
Research Acknowledgements
Collaborating groups
Recent and current
UCSF
Blackburn lab UCSF
Elissa Epel
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
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
Collaborating groups
Recent and current
UCSF
Blackburn lab UCSF
Elissa Epel
Jue Lin
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
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!
The end(s)