The science of cells that never get old
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0:01 - 0:03Where does the end begin?
-
0:03 - 0:07Well, for me, it all began
with this little fellow. -
0:08 - 0:10This adorable organism --
-
0:10 - 0:11well, I think it's adorable --
-
0:11 - 0:15is called Tetrahymena
and it's a single-celled creature. -
0:15 - 0:17It's also been known as pond scum.
-
0:17 - 0:21So that's right, my career
started with pond scum. -
0:22 - 0:25Now, it was no surprise
I became a scientist. -
0:25 - 0:27Growing up far away from here,
-
0:27 - 0:30as a little girl I was deadly curious
-
0:30 - 0:32about everything alive.
-
0:32 - 0:36I used to pick up lethally poisonous
stinging jellyfish and sing to them. -
0:38 - 0:41And so starting my career,
-
0:41 - 0:44I was deadly curious
about fundamental mysteries -
0:44 - 0:47of the most basic building blocks of life,
-
0:47 - 0:53and I was fortunate to live in a society
where that curiosity was valued. -
0:53 - 0:56Now, for me, this little
pond scum critter Tetrahymena -
0:56 - 0:58was a great way to study
the fundamental mystery -
0:58 - 1:00I was most curious about:
-
1:00 - 1:04those bundles of DNA
in our cells called chromosomes. -
1:05 - 1:11And it was because I was curious
about the very ends of chromosomes, -
1:11 - 1:13known as telomeres.
-
1:13 - 1:16Now, when I started my quest,
-
1:16 - 1:20all we knew was that they helped
protect the ends of chromosomes. -
1:20 - 1:21It was important when cells divide.
-
1:21 - 1:23It was really important,
-
1:23 - 1:27but I wanted to find out
what telomeres consisted of, -
1:27 - 1:30and for that, I needed a lot of them.
-
1:30 - 1:32And it so happens
that cute little Tetrahymena -
1:32 - 1:35has a lot of short linear chromosomes,
-
1:35 - 1:37around 20,000,
-
1:37 - 1:38so lots of telomeres.
-
1:39 - 1:44And I discovered that telomeres
consisted of special segments -
1:44 - 1:48of noncoding DNA right
at the very ends of chromosomes. -
1:48 - 1:50But here's a problem.
-
1:50 - 1:53Now, we all start life as a single cell.
-
1:53 - 1:55It multiples to two.
Two becomes four. Four becomes eight, -
1:55 - 1:59and on and on to form
the 200 million billion cells -
1:59 - 2:00that make up our adult body.
-
2:01 - 2:05And some of those cells
have to divide thousands of times. -
2:06 - 2:08In fact, even as I stand here before you,
-
2:09 - 2:12all throughout my body,
cells are furiously replenishing -
2:12 - 2:14to, well, keep me
standing here before you. -
2:15 - 2:19So every time a cell divides,
all of its DNA has to be copied, -
2:20 - 2:22all of the coding DNA
inside of those chromosomes, -
2:22 - 2:27because that carries
the vital operating instructions -
2:27 - 2:30that keep our cells in good working order,
-
2:30 - 2:34so my heart cells can keep a steady beat,
-
2:34 - 2:37which I assure you
they're not doing right now, -
2:37 - 2:40and my immune cells
-
2:40 - 2:44can fight off bacteria and viruses,
-
2:45 - 2:49and our brain cells
can save the memory of our first kiss -
2:49 - 2:52and keep on learning throughout life.
-
2:53 - 2:57But there is a glitch
in the way DNA is copied. -
2:57 - 3:00It is just one of those facts of life.
-
3:00 - 3:04Every time the cell divides
and the DNA is copied, -
3:04 - 3:08some of that DNA from the ends
gets worn down and shortened, -
3:08 - 3:10some of that telomere DNA.
-
3:10 - 3:12And think about it
-
3:12 - 3:16like the protective caps
at the ends of your shoelace. -
3:16 - 3:21And those keep the shoelace,
or the chromosome, from fraying, -
3:21 - 3:27and when that tip
gets too short, it falls off, -
3:27 - 3:30and that worn down telomere
sends a signal to the cells. -
3:32 - 3:34"The DNA is no longer being protected."
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3:34 - 3:36It sends a signal. Time to die.
-
3:36 - 3:37So, end of story.
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3:37 - 3:40Well, sorry, not so fast.
-
3:41 - 3:43It can't be the end of the story,
-
3:43 - 3:45because life hasn't died
off the face of the earth. -
3:45 - 3:48So I was curious:
-
3:48 - 3:50if such wear and tear is inevitable,
-
3:50 - 3:53how on earth does Mother Nature make sure
-
3:53 - 3:56we can keep our chromosomes intact?
-
3:57 - 3:59Now, remember that little
pond scum critter Tetrahymena? -
4:01 - 4:06The craziest thing was,
Tetrahymena cells never got old and died. -
4:07 - 4:11Their telomeres weren't shortening
as time marched on. -
4:13 - 4:15Sometimes they even got longer.
-
4:15 - 4:17Something else was at work,
-
4:17 - 4:20and believe me, that something
was not in any textbook. -
4:21 - 4:24So working in my lab with
my extraordinary student Carol Greider -- -
4:24 - 4:27and Carol and I shared
the Nobel Prize for this work -- -
4:27 - 4:29we began running experiments
-
4:30 - 4:33and we discovered
cells do have something else. -
4:34 - 4:37It was a previously undreamed-of enzyme
-
4:37 - 4:40that could replenish,
make longer, telomeres, -
4:41 - 4:43and we named it telomerase.
-
4:44 - 4:47And when we removed
our pond scum's telomerase, -
4:47 - 4:50their telomeres ran down and they died.
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4:51 - 4:53So it was thanks
to their plentiful telomerase -
4:53 - 4:57that our pond scum critters never got old.
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4:58 - 5:01OK, now, that's
an incredibly hopeful message -
5:02 - 5:05for us humans to be
receiving from pond scum, -
5:06 - 5:08because it turns out
-
5:08 - 5:11that as we humans age,
our telomeres do shorten, -
5:12 - 5:16and remarkably,
that shortening is aging us. -
5:16 - 5:18Generally speaking,
the longer your telomeres, -
5:18 - 5:19the better off you are.
-
5:21 - 5:22It's the overshortening of telomeres
-
5:22 - 5:26that leads us to feel and see
signs of aging. -
5:26 - 5:28My skin cells start to die
-
5:28 - 5:31and I start to see fine lines, wrinkles.
-
5:31 - 5:33Hair pigment cells die.
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5:33 - 5:35You start to see gray.
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5:35 - 5:37Immune system cells die.
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5:38 - 5:41You increase your risks of getting sick.
-
5:41 - 5:44In fact, the cumulative research
from the last 20 years -
5:45 - 5:48has made clear that telomere attrition
-
5:48 - 5:52is contributing to our risks
of getting cardiovascular diseases, -
5:52 - 5:56Alzheimer's, some cancers and diabetes,
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5:56 - 5:59the very conditions many of us die of.
-
6:01 - 6:04And so we have to think about this.
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6:05 - 6:07What is going on?
-
6:07 - 6:09This attrition,
-
6:09 - 6:11we look and we feel older, yeah.
-
6:11 - 6:15Our telomeres are losing
the war of attrition faster. -
6:15 - 6:18And those of us who feel youthful longer,
-
6:18 - 6:21it turns out our telomeres
are staying longer -
6:21 - 6:22for longer periods of time,
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6:22 - 6:25extending our feelings of youthfulness
-
6:25 - 6:28and reducing the risks
of all we most dread -
6:28 - 6:30as the birthdays go by.
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6:32 - 6:34OK,
-
6:34 - 6:36seems like a no-brainer.
-
6:37 - 6:40Now, if my telomeres are connected
-
6:40 - 6:44to how quickly
I'm going to feel and get old, -
6:44 - 6:48if my telomeres can be
renewed by my telomerase, -
6:48 - 6:53then all I have to do to reverse
the signs and symptoms of aging -
6:53 - 6:56is figure out where to buy
that Costco-sized bottle -
6:56 - 7:01of grade A organic
fair trade telomerase, right? -
7:01 - 7:02Great! Problem solved.
-
7:02 - 7:03(Applause)
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7:03 - 7:06Not so fast, I'm sorry.
-
7:06 - 7:10Alas, that's not the case.
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7:10 - 7:11OK. And why?
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7:11 - 7:15It's because human genetics has taught us
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7:15 - 7:19that when it comes to our telomerase,
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7:19 - 7:22we humans live on a knife edge.
-
7:22 - 7:23OK, simply put,
-
7:24 - 7:31yes, nudging up telomerase
does decrease the risks of some diseases, -
7:31 - 7:37but it also increases the risks
of certain and rather nasty cancers. -
7:37 - 7:42So even if you could buy
that Costco-sized bottle of telomerase, -
7:42 - 7:49and there are many websites
marketing such dubious products, -
7:49 - 7:54the problem is you could
nudge up your risks of cancers. -
7:55 - 7:56And we don't want that.
-
7:57 - 8:00Now, don't worry,
-
8:00 - 8:05and because, while I think
it's kind of funny that right now, -
8:05 - 8:09you know, many of us may be thinking,
"Well, I'd rather be like pond scum," ... -
8:11 - 8:14(Laughter)
-
8:15 - 8:16there is something for us humans
-
8:16 - 8:19in the story of telomeres
and their maintenance. -
8:19 - 8:20But I want to get one thing clear.
-
8:21 - 8:24It isn't about enormously
extending human lifespan -
8:24 - 8:26or immortality.
-
8:26 - 8:29It's about health span.
-
8:29 - 8:31Now, health span is the number
of years of your life -
8:31 - 8:35when you're free of disease,
you're healthy, you're productive, -
8:35 - 8:37you're zestfully enjoying life.
-
8:37 - 8:40Disease span, the opposite of health span,
-
8:40 - 8:44is the time of your life
spent feeling old and sick and dying. -
8:44 - 8:47So the real question becomes,
-
8:47 - 8:49OK, if I can't guzzle telomerase,
-
8:51 - 8:54do I have control
over my telomeres' length -
8:54 - 8:58and hence my well-being, my health,
-
8:58 - 9:00without those downsides of cancer risks?
-
9:01 - 9:03OK?
-
9:03 - 9:06So, it's the year 2000.
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9:06 - 9:11Now, I've been minutely scrutinizing
little teeny tiny telomeres -
9:11 - 9:13very happily for many years,
-
9:13 - 9:17when into my lab walks
a psychologist named Elissa Epel. -
9:17 - 9:24Now, Elissa's expertise is in the effects
of severe, chronic psychological stress -
9:24 - 9:26on our mind's and our body's health.
-
9:27 - 9:29And there she was standing in my lab,
-
9:29 - 9:34which ironically overlooked
the entrance to a mortuary, and -- -
9:34 - 9:37(Laughter)
-
9:37 - 9:39And she had a life-and-death
question for me. -
9:39 - 9:43"What happens to telomeres
in people who are chronically stressed?" -
9:43 - 9:44she asked me.
-
9:44 - 9:46You see, she'd been studying caregivers,
-
9:46 - 9:52and specifically mothers of children
with a chronic condition, -
9:52 - 9:57be it gut disorder,
be it autism, you name it -- -
9:57 - 10:02a group obviously under enormous
and prolonged psychological stress. -
10:05 - 10:07I have to say, her question
-
10:07 - 10:09changed me profoundly.
-
10:09 - 10:12See, all this time
I had been thinking of telomeres -
10:12 - 10:15as those miniscule
molecular structures that they are, -
10:15 - 10:18and the genes that control telomeres.
-
10:19 - 10:22And when Elissa asked me
about studying caregivers, -
10:22 - 10:25I suddenly saw telomeres
in a whole new light. -
10:28 - 10:30I saw beyond the genes and the chromosomes
-
10:30 - 10:34into the lives of the real people
we were studying. -
10:34 - 10:36And I'm a mom myself,
-
10:37 - 10:38and at that moment,
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10:38 - 10:42I was struck by the image of these women
-
10:42 - 10:45dealing with a child with a condition
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10:46 - 10:49very difficult to deal with,
often without help. -
10:50 - 10:53And such women, simply,
-
10:53 - 10:57often look worn down.
-
10:58 - 11:02So was it possible their telomeres
were worn down as well? -
11:02 - 11:05So our collective curiosity
went into overdrive. -
11:05 - 11:09Elissa selected for our first study
a group of such caregiving mothers, -
11:09 - 11:13and we wanted to ask:
What's the length of their telomeres -
11:14 - 11:18compared with the number of years
that they have been caregiving -
11:18 - 11:21for their child with a chronic condition?
-
11:21 - 11:24So four years go by
-
11:24 - 11:27and the day comes
when all the results are in, -
11:27 - 11:30and Elissa looked down
at our first scatterplot -
11:30 - 11:31and literally gasped,
-
11:33 - 11:36because there was a pattern to the data,
-
11:36 - 11:41and it was the exact gradient
that we most feared might exist. -
11:41 - 11:43It was right there on the page.
-
11:43 - 11:45The longer, the more years that is,
-
11:45 - 11:48the mother had been
in this caregiving situation, -
11:48 - 11:50no matter her age,
-
11:50 - 11:52the shorter were her telomeres.
-
11:52 - 11:55And the more she perceived
-
11:55 - 12:00her situation as being more stressful,
-
12:00 - 12:05the lower was her telomerase
and the shorter were her telomeres. -
12:07 - 12:11So we had discovered something unheard of:
-
12:11 - 12:15the more chronic stress you are under,
the shorter your telomeres, -
12:15 - 12:20meaning the more likely you were
to fall victim to an early disease span -
12:20 - 12:22and perhaps untimely death.
-
12:23 - 12:27Our findings meant
that people's life events -
12:27 - 12:30and the way we respond to these events
-
12:30 - 12:34can change how you
maintain your telomeres. -
12:36 - 12:41So telomere length wasn't
just a matter of age counted in years. -
12:43 - 12:44Elissa's question to me,
-
12:44 - 12:48back when she first came to my lab,
indeed had been a life-and-death question. -
12:50 - 12:54Now, luckily, hidden
in that data there was hope. -
12:54 - 12:56We noticed that some mothers,
-
12:56 - 13:00despite having been carefully caring
for their children for many years, -
13:00 - 13:02had been able to maintain their telomeres.
-
13:04 - 13:09So studying these women closely revealed
that they were resilient to stress. -
13:09 - 13:12Somehow they were able
to experience their circumstances -
13:12 - 13:14not as a threat day in and day out
-
13:14 - 13:16but as a challenge,
-
13:16 - 13:20and this has led to a very important
insight for all of us: -
13:20 - 13:24we have control over the way we age
-
13:24 - 13:26all the way down into our cells.
-
13:28 - 13:31OK, now our initial curiosity
became infectious. -
13:31 - 13:34Thousands of scientists
from different fields -
13:34 - 13:37added their expertise
to telomere research, -
13:37 - 13:39and the findings have poured in.
-
13:40 - 13:45It's up to over 10,000
scientific papers and counting. -
13:47 - 13:50So several studies
rapidly confirmed our initial finding -
13:50 - 13:53that yes, chronic stress
is bad for telomeres. -
13:55 - 13:56And now many are revealing
-
13:56 - 14:00that we have more control
over this particular aging process -
14:00 - 14:03than any of us could ever have imagined.
-
14:03 - 14:04A few examples:
-
14:04 - 14:08a study from the University
of California, Los Angeles -
14:08 - 14:14of people who are caring
for a relative with dementia, long-term, -
14:14 - 14:19and looked at their caregiver's
telomere maintenance capacity -
14:19 - 14:21and found that it was improved
-
14:21 - 14:25by them practicing a form of meditation
-
14:25 - 14:28for as little as 12 minutes
a day for two months. -
14:30 - 14:31Attitude matters.
-
14:31 - 14:34If you're habitually a negative thinker,
-
14:34 - 14:40you typically see a stressful situation
with a threat stress response, -
14:40 - 14:42meaning if your boss wants to see you,
-
14:42 - 14:44you automatically think,
"I'm about to be fired," -
14:44 - 14:46and your blood vessels constrict,
-
14:46 - 14:50and your level of the stress
hormone cortisol creeps up, -
14:50 - 14:52and then it stays up,
-
14:52 - 14:57and over time, that persistently
high level of the cortisol -
14:57 - 14:59actually damps down your telomerase.
-
14:59 - 15:01Not good for your telomeres.
-
15:02 - 15:03On the other hand,
-
15:03 - 15:09if you typically see something stressful
as a challenge to be tackled, -
15:09 - 15:13then blood flows to your heart
and to your brain, -
15:13 - 15:18and you experience a brief
but energizing spike of cortisol. -
15:18 - 15:20And thanks to that habitual
"bring it on" attitude, -
15:20 - 15:23your telomeres do just fine.
-
15:26 - 15:27So ...
-
15:28 - 15:31What is all of this telling us?
-
15:33 - 15:35Your telomeres do just fine.
-
15:35 - 15:41You really do have power
to change what is happening -
15:41 - 15:44to your own telomeres.
-
15:44 - 15:50But our curiosity
just got more and more intense, -
15:51 - 15:53because we started to wonder,
-
15:53 - 15:56what about factors outside our own skin?
-
15:56 - 16:00Could they impact
our telomere maintenance as well? -
16:01 - 16:04You know, we humans
are intensely social beings. -
16:04 - 16:08Was it even possible
that our telomeres were social as well? -
16:09 - 16:11And the results have been startling.
-
16:12 - 16:14As early as childhood,
-
16:16 - 16:20emotional neglect, exposure to violence,
-
16:20 - 16:22bullying and racism
-
16:22 - 16:26all impact your telomeres,
and the effects are long-term. -
16:28 - 16:30Can you imagine the impact on children
-
16:30 - 16:32of living years in a war zone?
-
16:34 - 16:36People who can't trust their neighbors
-
16:36 - 16:39and who don't feel safe
in their neighborhoods -
16:39 - 16:41consistently have shorter telomeres.
-
16:43 - 16:46So your home address
matters for telomeres as well. -
16:46 - 16:47On the flip side,
-
16:48 - 16:51tight-knit communities,
being in a marriage long-term, -
16:52 - 16:54and lifelong friendships, even,
-
16:54 - 16:57all improve telomere maintenance.
-
16:58 - 17:02So what is all this telling us?
-
17:02 - 17:06It's telling us that I have the power
to impact my own telomeres, -
17:06 - 17:10and I also have the power to impact yours.
-
17:10 - 17:15Telomere science has told us
just how interconnected we all are. -
17:18 - 17:19But I'm still curious.
-
17:20 - 17:22I do wonder
-
17:23 - 17:25what legacy all of us
-
17:27 - 17:28will leave for the next generation?
-
17:29 - 17:31Will we invest
-
17:31 - 17:34in the next young woman or man
-
17:34 - 17:38peering through a microscope
at the next little critter, -
17:38 - 17:40the next bit of pond scum,
-
17:41 - 17:44curious about a question
we don't even know today is a question? -
17:44 - 17:47It could be a great question
that could impact all the world. -
17:47 - 17:51And maybe, maybe you're curious about you.
-
17:52 - 17:54Now that you know
how to protect your telomeres, -
17:54 - 17:56are you curious what are you going to do
-
17:56 - 17:59with all those decades
of brimming good health? -
17:59 - 18:03And now that you know you could impact
the telomeres of others, -
18:04 - 18:05are you curious
-
18:06 - 18:08how will you make a difference?
-
18:10 - 18:14And now that you know the power
of curiosity to change the world, -
18:14 - 18:20how will you make sure
that the world invests in curiosity -
18:20 - 18:25for the sake of the generations
that will come after us? -
18:27 - 18:28Thank you.
-
18:28 - 18:33(Applause)
- Title:
- The science of cells that never get old
- Speaker:
- Elizabeth Blackburn
- Description:
-
What makes our bodies age ... our skin wrinkle, our hair turn white, our immune systems weaken? Biologist Elizabeth Blackburn shares a Nobel Prize for her work finding out the answer, with the discovery of telomerase: an enzyme that replenishes the caps at the end of chromosomes, which break down when cells divide. Learn more about Blackburn's groundbreaking research -- including how we might have more control over aging than we think.
- Video Language:
- English
- Team:
closed TED
- Project:
- TEDTalks
- Duration:
- 18:46
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Brian Greene edited English subtitles for The science of cells that never get old | |
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Brian Greene edited English subtitles for The science of cells that never get old | |
![]() |
Brian Greene edited English subtitles for The science of cells that never get old | |
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Brian Greene approved English subtitles for The science of cells that never get old | |
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Brian Greene edited English subtitles for The science of cells that never get old | |
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Joanna Pietrulewicz accepted English subtitles for The science of cells that never get old | |
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Joanna Pietrulewicz edited English subtitles for The science of cells that never get old | |
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Joanna Pietrulewicz edited English subtitles for The science of cells that never get old |