人如其食—環境, 飲食與基因調控
You are what you eat— Environment, diet and gene regulation
蔡幸真
Hsing-Chen Tsai, MD, PhD
台大醫學院毒理所 副教授
台大醫院內科部 主治醫師
課前討論
課前討論
影片讓我重新思考「我們是誰」這個問題。人類的生命並
不是一個固定的劇本，而是一場持續進行的創作。這種基
因與環境的互動提醒我們，雖然不能選擇出身，但可以選
擇如何改變自己，以及如何影響身邊的人與後代。我覺得
這樣的洞察讓人充滿希望，因為我們每個人都有力量塑造
未來。
課前討論
這兩段影片雖然分別探討了不同的主題，但它們之間存在內在
的聯繫。雙胞胎和領養研究揭示了基因與環境的交互作用，而
表觀遺傳學進一步細化了環境如何改變基因表達的機制。它們
共同強調了一個觀點：我們的命運並非完全由基因所決定，也
不是完全由環境所塑造，而是兩者共同影響的結果。 這讓我想
到，我們作為個體，不僅僅是基因和環境的被動受體，我們也
能通過選擇改變自身的發展路徑。例如，我們可以選擇健康的
飲食、學習應對壓力的方法，甚至透過努力改變環境來為下一
代創造更好的未來。科學在這方面的發現讓我感到驚嘆，同時
也讓我對自己的生活選擇更加重視。
總結來說，這兩段影片不僅拓展了我的知識，也啟發了我對基
因與環境互動的反思。我們的生命不僅僅是一場科學現象，更
是一段能夠被選擇和改變的旅程。這種科學與人文的交織，正
是這兩段影片帶給我的最大啟示。
課前討論
這兩種研究讓我明白，人類發展並非簡單地由「先天」或
「後天」單獨決定，而是兩者相互作用的結果。基因提供
了生命的藍圖，而環境則決定了這張藍圖如何被實現。我
們可能無法改變先天的條件，但我們可以通過創造良好的
環境，讓自己和他人活出更好的可能性。
課前討論
第一部影片:「基因提供潛能，環境決定發揮」
第二部影片: 「基因不是命運」
人生雖然不是完全由我們控制，但我們有能力去改變其中的
一部分。
課前討論
人們一直都想要知道基因在運作上背後真正的原理，以及
想要知道如何人為操作基因。為此雙胞胎就是很好的實驗
以及對照對象，但比起科學家實驗的成功與否，我更關注
的焦點是這些有關雙胞胎的研究是否會嚴重影響到這些雙
胞胎們的人生與身心發展，導致對其產生不良影響，而衍
生出道德層面上的問題。。
課前討論
當初以為「先天與後天」只是個單純的二選一問題，看完這兩部影片
之後，我才真正理解這兩個因素其實彼此糾纏，幾乎很難完全分開來
看。第一部影片中，雙胞胎與收養研究提供了一種相對清晰的方式去
拆解遺傳與環境的影響，尤其是透過比較同卵與異卵雙胞胎在相同環
境下的行為差異，或是收養兒童與其生物與養父母的相似度，這種設
計的邏輯讓我很有感。它不只是方法設計上的巧思，更反映了我們在
理解人類行為、心理疾病乃至人格特質時，其實早已離不開科學與統
計的支撐。
不過真正讓我開始重新思考「遺傳」意義的是第二部影片關於表觀遺
傳學的介紹。過去總覺得「DNA寫好了就定了」，但原來基因怎麼被
「打開」或「關閉」，甚至還會因為一個媽媽吃了什麼、生活經歷是
什麼，就出現不同結果。這讓我想到，即使兩個人有完全相同的基因，
如果走過的路不同，可能真的會成為完全不同的人。這不只是生命科
學上的發現，也有種帶點哲學意味的震撼感。
Sink or Float?
Tap Water
Corn syrup
Salt Water
Same toxin, different toxic responses
Nature vs. Nurture
毒性反應
疾病
環境、飲食
基因
10
什麼是基因?
基因 (Gene): 基因是遺傳物質，攜帶遺傳訊息，
決定生物體特質。
例如：基因可決定眼睛的顏色, 身高, 胖瘦, 頭髮捲度等。
Wikipedia:
A gene is the molecular unit of heredity of a living organism.
A modern working definition of a gene is “a locatable region of genomic
sequence, corresponding to a unit of inheritance” – DNA｀
11
基因 (Genes)決定生物體特質
12
基因在哪裡?
人
細胞
細胞核 染色體 DNA
The American Society of Human Genetics
人類的染色體 (Chromosomes),
22 XX or 22 XY
14
DNA
A
G
T
C
• 生物遺傳物質
• 存在於所有的細胞中
• 鹼基:
腺嘌呤(A)
鳥嘌呤(G)
胞嘧啶(C)
胸腺嘧啶(T)
Q:人類約有幾個基因?
(1) 200個
(2) 2,000個
(3) 20,000個
(4) 200,000個
16
個體的基因組成在精卵結合(受精)時就決定了
精子
卵子
17
http://missinglink.ucsf.edu/lm/genes_and_genomes/imprinting.html
基因的活性受到調控
Genes can be turned on or turned off
基因表達
基因不表達
18
基因表達
DNA
RNA
蛋白質
是誰打開(關閉)基因的開關?
Nature vs. Nurture
毒性反應
疾病
環境、飲食
基因
21
飲食影響基因活性
22
飲食影響基因活性
23
環境影響基因活性
24
The Gulf of Mexico oil spill, 2010
(Deepwater Horizon oil spill)
26
The Gulf of Mexico oil spill, 2010
(Deepwater Horizon oil spill)
27
生活型態影響基因活性
stress
Smoking and alcohol consumption
Working habits
Physical activity
28
如何研究環境與飲食對疾病的影響?
疾病
環境、飲食
基因
29
同卵雙胞胎 Identical twins
100% gene
30
100% home environment
Identical Twins Not So Identical
-- understand how nature and nurture work together
(how environment and genes interact)
31
雙胞胎研究：基因與環境交互作用
同卵雙生
異卵雙生
同卵雙胞胎
異卵雙胞胎
兄弟姊妹
Monozygotic
Twins
Dizygotic
Twins
Regular
Siblings
Identical Twins Fraternal Twins
Genes
(Nature)
Environment
(Nuture)
100%
50%
50%
100%?
100%?
100%?
Identical Twins > Fraternal Twins ??
Identical Twins ≈ Fraternal Twins ??
身高
基因影響較大
閱讀障礙
自閉症
失智症
精神分裂症
酗酒
躁鬱症
高血壓
糖尿病
多發性結節硬化症
乳癌
克隆氏症
中風
類風濕性關節炎
環境影響較大 34
《三個一模一樣的陌生人》
Three Identical Strangers
羅伯特、艾迪與大衛是同卵三胞胎，他們
剛出生的時候，因為原生家庭無力養育，
透過一家慈善機構的安排，分別被三個家
庭所領養。慈善機構告訴他們的原生父母，
很少有家庭有能力一次收養三個小孩，所
以必須將他們分別出養。因此，三胞胎與
領養家庭都不知道其他兄弟的存在。
人之所以成為現在的樣子，究竟是先天因
素的作用大，還是後天環境的影響深？
Robert Shafran
Edward Galland
David Kellman
有趣的是，儘管從小在不同的家庭長大，三胞胎兄弟發現
自己在許多方面很相似，除了長相身高之外，他們喜歡的
食物口味、抽的香菸口味，熱衷的摔角運動幾乎一模一樣。
他們的傳奇故事在小鎮上造成轟動，許多媒體與談話性節
目找上他們，請他們分享這個奇特的人生經歷。後來，為
了慶祝他們新發現的兄弟關係，三胞胎搬進同一個住處，
甚至一起經營一家餐廳，開啟嶄新的生活。
人之所以成為現在的樣
子，究竟是先天因素的
作用大，還是後天環境
的影響深？
基因
環境
基因
環境
飲食
生活型態
毒物
藥物
…...
You are what you eat?
39
Apis mellifera
Western Honey Bee
Wikipedia
40
Egg
What differentiates the sterile worker bees from the fertile
queen is not genetics, but the diet that they follow as larvae
Fertilized
Light feeding
工蜂
Unfertilized
Heavy feeding
+ Royal Jelly
女王蜂
雄蜂
41
女王蜂的養成 What Makes a Queen Bee?
Royal Jelly
蜂王乳
http://www.votemeyo.com/en/topic/763/Royal-jelly-is-all-What-you-need-for-a-Good-Health-!
vy
A /a mice
飲食未造成基因突變但可改變基因表達
Dietary supplements can alter gene expression
without mutating the gene itself
Two genetically identical mice, agouti
The mother of the skinny
brown mouse received
dietary supplements with
folic acid (葉酸),
vitamin B12(維他命B12),
choline chloride(氯化膽鹼),
and anhydrous betaine(甜菜
鹼)
(all chemicals that donate
methyl group to DNA)
44 2003
Waterland and Jirtle, Mol Cell Biol,
懷孕時之飲食影響子代老鼠的毛色
folic acid
vitamin B12
choline chloride
betaine
“Diet, nutritional supplements can alter
the development in utero to such an
extent that it changes the offspring's
characteristics for life, and potentially
that of future generations"
Waterland and Jirtle, Mol Cell Biol, 2003
Fat fathers affect daughters' health
LETTER
doi:10.1038/nature09491
Chronic high-fat diet in fathers programs b-cell
dysfunction in female rat offspring
Sheau-Fang Ng1, Ruby C. Y. Lin2, D. Ross Laybutt3, Romain Barres4, Julie A. Owens5 & Margaret J. Morris1
The global prevalence of obesity is increasing across most ages in
both sexes. This is contributing to the early emergence of type 2
diabetes and its related epidemic1,2. Having either parent obese is
an independent risk factor for childhood obesity3. Although the
detrimental impacts of diet-induced maternal obesity on adiposity
and metabolism in offspring are well established4, the extent of any
contribution of obese fathers is unclear, particularly the role of
non-genetic factors in the causal pathway. Here we show that paternal
high-fat-diet (HFD) exposure programs b-cell ‘dysfunction’ in rat
F1 female offspring. Chronic HFD consumption in Sprague–Dawley
fathers induced increased body weight, adiposity, impaired glucose
tolerance and insulin sensitivity. Relative to controls, their female
offspring had an early onset of impaired insulin secretion and glucose tolerance that worsened with time, and normal adiposity.
Paternal HFD altered the expression of 642 pancreatic islet genes
in adult female offspring (P , 0.01); genes belonged to 13 functional clusters, including cation and ATP binding, cytoskeleton
and intracellular transport. Broader pathway analysis of 2,492 genes
differentially expressed (P , 0.05) demonstrated involvement of
calcium-, MAPK- and Wnt-signalling pathways, apoptosis and
the cell cycle. Hypomethylation of the Il13ra2 gene, which showed
the highest fold difference in expression (1.76-fold increase), was
demonstrated. This is the first report in mammals of non-genetic,
intergenerational transmission of metabolic sequelae of a HFD
from father to offspring.
Increasing evidence indicates an important biological role of fathers
in obesity and metabolic programming of their offspring5,6. Most
human obesity seems to be related to complex gene–environment interactions7. Although some alleles associated with obesity are inherited
solely from the father8,9, parental environmental exposures can also
affect offspring phenotype10, with the potential to contribute to the
rapid increase in obesity. Susceptibility of the metabolic phenotype to
environmentally initiated change also extends into early life through
control diet (Supplementary Table 1). As expected, HFD males had
increased body weight, energy intake, adiposity and plasma leptin and
liver mass (Fig. 1a–c and Table 1), but reduced skeletal muscle mass
relative to body weight (P 5 0.017). The HFD males were also glucose
Table 1 | Hormonal and metabolic parameters and pancreas
morphology
Group and parameter
Control
HFD
Fathers
Body weight (g)
Length (cm)
Liver (g)
BAT (mg)
Mesenteric WAT (g)
Retroperitoneal WAT (g)
Gonadal WAT (g)
Sum of WAT (g)
Leptin (ng ml21)
Glucose (mM)
Insulin (ng ml21)
HOMA-IR
Female offspring
Body weight (g)
Length (cm)
Liver (g)
BAT (mg)
Selected skeletal muscle
mass (mg)
Mesenteric WAT (g)
Retroperitoneal WAT (g)
Gonadal WAT (g)
Sum of WAT (g)
Leptin (ng ml21)
Triglyceride (mM)
NEFA (mEq l21)
Pancreas morphology
Total islet area
(percentage pancreas area)
n58
550 6 13
26.8 6 0.3
15.16 6 0.43
0.462 6 0.026
4.76 6 0.35
8.85 6 0.60
7.56 6 0.32
21.17 6 0.75
2.70 6 0.30
4.71 6 0.08
0.18 6 0.02
0.88 6 0.11
n58
253 6 8
22.6 6 0.2
7.15 6 0.19
0.19 6 0.02
0.78 6 0.02
n59
705 6 17
27.8 6 0.3
19.51 6 1.23
0.779 6 0.100
12.43 6 1.23
30.85 6 3.09
20.83 6 1.10
64.10 6 4.84
13.26 6 1.99
5.43 6 0.16
0.47 6 0.07
2.29 6 0.18
n59
260 6 5
22.3 6 0.1
7.34 6 0.16
0.21 6 0.01
0.77 6 0.03
2.14 6 0.16
2.50 6 0.37
2.58 6 0.10
6.76 6 0.32
0.89 6 0.09
0.92 6 0.14
2.22 6 0.12
n57
1.17 6 0.09
2.28 6 0.20
2.81 6 0.36
2.80 6 0.48
7.87 6 0.89
1.06 6 0.16
0.78 6 0.12
2.59 6 0.33
n57
0.90 6 0.08
P value
,0.0005
0.017
0.006
0.013
,0.0005
,0.0005
,0.0005
,0.0005
,0.0005
0.002
0.002
,0.0005
Margaret Morris’s laboratory
Nature, Oct 2010
0.92
0.28
0.46
0.43
0.66
0.59
0.55
0.67
0.28
0.38
0.46
0.32
0.040
47
胰臟
胰島
Insulin
胰島素
Female offspring demonstrate impaired glucose tolerance
and insulin secretion
Body weight
Growth rate
Energy intake
Father rat,
high fat diet vs. control diet
高脂飲食
49
Female offspring demonstrate impaired glucose tolerance
and insulin secretion 葡萄糖耐受度及胰島素分泌變差
Father rat,
high fat diet vs. control diet
At 6 weeks
At 6 weeks
At 12 weeks
高脂飲食
At 12 weeks
50
Differentially expressed islet genes (P < 0.05) of female
offspring in functionally enriched pathways
胰島素細胞基因表達差異
51
FEATURE | FROM GREAT-GRANDMA TO YOU
Grandma
TO
You
Epigenetic changes
reach down through
the generations
By Tina Hesman Saey
L
ike many women with parents of
the Mad Men generation, Susan
Murphy grew up in a household
full of cigarette smoke. Both dad
and mom smoked heavily, even while
Murphy was still in her mother’s womb.
“That explains a lot,” Murphy quips,
poking fun at herself.
18 | SCIENCE NEWS | April 6, 2013
inherited.indd 18
But Murphy isn’t worried about her
own health. She’s fine. Her children
aren’t, though. One boy died of cancer as
a toddler. Another has autism. And her
daughter has attention deficit disorder.
Murphy knows the scientific evidence
isn’t in yet, but she still can’t help wondering whether their fates might have
been affected by her exposure to tobacco
smoke before she was born.
Murphy, a researcher at Duke University, studies links between a mother’s
diet and chemical exposures during
pregnancy with the child’s later health.
She and others have established that
the womb is the antithesis of Las Vegas;
隔代效應
Transgenerational
effects?
Stuck for generations
Investigating how those marks travel to
future generations is a new twist in the
field of epigenetics. Originally, epigenetics
researchers focused on the developmental processes that allow individual cells
to specialize despite the fact that all the
cells have the same DNA. It turned out
that chemical tags that get stuck to DNA
or to the proteins around which DNA is
BOBBIEO/GETTY IMAGES
FROM
what happens there not only doesn’t
stay there, it can influence a child’s
health for life.
Now, animal studies and a smattering of human data suggest such prenatal
effects could reach farther down the
family tree: The vices, virtues, inadvertent actions and accidental exposures
of a pregnant mother may pose health
consequences for her grandchildren and
great-grandchildren, and perhaps even
their offspring.
Scientists have long known that radiation or certain chemicals can cause typos
in a developing fetus’s genome — his or
her genetic instruction book. Such mutations can get passed along to future
generations in the DNA of sperm or egg
cells. While exposure to sex hormones
or a high-fat diet in the womb doesn’t
directly change or damage DNA, those
sorts of exposures can induce scribblings
in the genome’s margins that can also be
passed down.
The resulting health effects are not
produced by altering DNA itself. Rather
they stem from changes in chemical tags
on DNA or its associated proteins, or to
actions by RNA, another type of genetic
molecule. All of these are exactly the types
of changes that scientists have always
assumed cannot be inherited. Their very
name, epigenetic, literally means “over
and above” or “beyond” genetics.
When these changes are inherited,
scientists have found, the implications
can be staggering. Part of your risk of
disease may be determined by what
your great-grandparents ate, not just the
genes they passed on. Some researchers
even believe that the long-lasting effects
of these chemical marks helped shape
human evolution.
www.sciencenews.org
3/20/13 4:04 PM
52
F0
F1
F2
F3
A
B
C
53
Jirtle and Skinner Nature Review Genetics 2007
Q: 鼠媽媽接受環境賀爾蒙暴露後，
請問哪一代老鼠(A、B、C)會有問題?
(1) A
(2) AB
(3) ABC
(4) BC
54
The Toxins That Affected Your Great-Grandparents
Could Be In Your Genes
CORRECTED 7 MAY 2010; SEE LAST PAGE
Epigenetic Transgenerational
Actions of Endocrine Disruptors
and Male Fertility
Matthew D. Anway, Andrea S. Cupp,* Mehmet Uzumcu,.
Michael K. SkinnerTransgenerational effects of environmental toxins require either a chromosomal
or epigenetic alteration in the germ line. Transient exposure of a gestating female rat during the period of gonadal sex determination to the endocrine disruptors vinclozolin (an antiandrogenic compound) or methoxychlor (an
estrogenic compound) induced an adult phenotype in the F1 generation of
decreased spermatogenic capacity (cell number and viability) and increased
incidence of male infertility. These effects were transferred through the male
germ line to nearly all males of all subsequent generations examined (that is, F1
to F4). The effects on reproduction correlate with altered DNA methylation
patterns in the germ line. The ability of an environmental factor (for example,
endocrine disruptor) to reprogram the germ line and to promote a transgenerational disease state has significant implications for evolutionary biology and
disease etiology.
Treatments, such as irradiation and chemotherapy, and compounds, such as environmental toxins, pose a threat to the integrity of the
genome. Studies have shown that these
agents can result in genetic or developmental
defects in the offspring or F1 generation from
an exposed gestating mother. The ability of an
external agent to induce a transgenerational effect requires stable chromosomal alterations or
an epigenetic phenomenon such as DNA
methylation (1). In the present study, transgenerational refers to a germline transmission
to multiple generations, minimally to the F2
generation. Transgenerational effects of irradiation were the first to be identified through
transmission of DNA mutations in the germ
line to multiple generations (2), often associated with tumor formation. Chemotherapeutic
treatments (3) and environmental toxins such as
endocrine disruptors (4) can cause effects in the
F1 generation, but they have not been shown to
affect the F2 generation. Although no effects
have been shown to be transgenerational, the
potential impact of such transgenerational
effects of endocrine disruptors has been
discussed (5).
Epigenetic alterations that could lead to
netic trait requires a permanent reprogramming of the germ line. During mammalian
germ cell development the methylation state
of the genome is reprogrammed. As primordial germ cells (PGCs) migrate down the
genital ridge, a demethylation starts and is
complete on colonization in the early gonad
(7, 8). Germ cells in the gonad then undergo
remethylation in a sex-specific manner during gonadal sex determination (9). Although
demethylation may not require the gonadal
somatic cells, remethylation of the germ line
appears to be dependent on association with
the somatic cells in the gonads (7). Gonadal
sex determination and testis development
occur between embryonic days 12 and 15
(E12 to E15) in the rat (after midgestation in
the human) and are initiated by the differentiation of precursor Sertoli cells in response
to the testis-determining factor Sry. Aggregation of the precursor Sertoli cells, PGCs,
and migrating mesonephros cells (precursor
peritubular myoid cells) promotes testis morphogenesis and cord formation (10, 11). During the period of gonadal sex determination,
the fetal testis contains steroid receptors and is
a target for endocrine agents. The androgen
tional transmission of an altered phenotype
or genetic trait.
The estrogenic and antiandrogenic endocrine disruptors used in the current study are
methoxychlor and vinclozolin, respectively.
Vinclozolin is a commonly used fungicide in
the wine industry that is metabolized into more
active (i.e., higher affinity binding to androgen receptor) compounds (14). Methoxychlor
is used as a pesticide to replace DDT and is
metabolized into active compounds with the
ERa agonist, the ERb antagonist, and antiandrogenic activity (15–17). Vinclozolin or
methoxychlor exposure in the late embryonic
or early postnatal period influences sexual differentiation, gonad formation, and reproductive
functions in the F1 generation (14, 18, 19).
Transient exposure (daily intraperitoneal injection of 100 or 200 mg/kg dose) of a gestating
female rat to methoxychlor or vinclozolin between E8 and E15 promotes reduced spermatogenic capacity associated with increased
spermatogenic cell apoptosis and decreased
sperm number and motility in the adult F1
generation (20, 21). A similar exposure between E15 and E20 had no effect on the F1
generation testis (20, 21). These observations
were extended in the present study by treating the gestating mother with vinclozolin. F1
generation male rats were mated with F1 generation females from different litters. Subsequent breeding continued for four generations
with sufficient numbers of animals to avoid
sibling inbreeding. Adult males from F1, F2,
F3, and F4 generations between postnatal days
PND60 and PND180 were killed. Testes were
isolated for histological examination, and caudal epididymal sperm were collected for sperm
counts and motility measurements. Only the
original gestating mother (F0) of the F1 generation received a transient endocrine disruptor
treatment. Control groups of animals were bred
in a similar manner after vehicle treatment
(dimethylsulfoxide buffer alone injected) of
the F0 gestating mother. Analysis of cellular
apoptosis demonstrated a greater than twofold increase in spermatogenic cell apoptosis
in the vinclozolin treatment animals for the
F1 to F4 generations (Fig. 1A). Sperm numbers were reduced minimally, 20%, and sperm
forward motility was reduced about 25 to 35%
for vinclozolin generation animals (Fig. 1, B
Downloaded from www.sciencemag.org on December 9, 2014
REPORTS
Michael Skinner’s laboratory
Science, June 2005
55
免克寧
Vinclozolin
真菌抑制劑(農藥)
睪丸內
細胞凋亡數
精子數
精子活動力
Vinclozolin
A fungicide used in the wine industry.
An anti-androgenic compound
• Transient exposure of a gestating female rat during the period of gonadal sex determination
to the endocrine disruptors vinclozolin or methoxychlor induced an adult phenotype in the F1
generation of decreased spermatogenic capacity (cell number and viability) and increased
incidence of male infertility.
• These effects were transferred through the male germ line to nearly all males of all
subsequent generations examined (that is, F1 to F4)
57
High-fat Diets In Pregnant Animals Influence Breast Cancer Risk In
Multiple Generations
ARTICLE
Received 22 Mar 2012 | Accepted 10 Aug 2012 | Published 11 Sep 2012
DOI: 10.1038/ncomms2058
High-fat or ethinyl-oestradiol intake during
pregnancy increases mammary cancer risk
in several generations of offspring
Sonia de Assis1, Anni Warri1,2, M. Idalia Cruz1, Olusola Laja1, Ye Tian3, Bai Zhang3,4, Yue Wang3,
Tim Hui-Ming Huang5 & Leena Hilakivi-Clarke1
Maternal exposures to environmental factors during pregnancy influence the risk of many
chronic adult-onset diseases in the offspring. Here we investigate whether feeding pregnant
rats a high-fat (HF)- or ethinyl-oestradiol (EE2)-supplemented diet affects carcinogen-induced
mammary cancer risk in daughters, granddaughters and great-granddaughters. We show that
mammary tumourigenesis is higher in daughters and granddaughters of HF rat dams and in
daughters and great-granddaughters of EE2 rat dams. Outcross experiments suggest that the
increase in mammary cancer risk is transmitted to HF granddaughters equally through the female
or male germ lines, but it is only transmitted to EE2 granddaughters through the female germ
line. The effects of maternal EE2 exposure on offspring’s mammary cancer risk are associated
with changes in the DNA methylation machinery and methylation patterns in mammary
tissue of all three EE2 generations. We conclude that dietary and oestrogenic exposures in
pregnancy increase breast cancer risk in multiple generations of offspring, possibly through
epigenetic means.
Sonia de Assis & Leena Hilakivi-Clarke
Nature Communications, Sep 2012
58
高脂飲食
雌激素
59
de Assis et al. Nature Comm, 2012
荷蘭大饑荒 (Dutch Famine of 1944)
• Known as the Hongerwinter ("Hunger winter")
in Dutch,
• Took place in the German-occupied part of
the Netherlands, during the winter of 19441945, near the end of World War II.
• The German administration cut off food and
fuel shipments from farm areas.
• Some 4.5 million were affected; about 22,000
died because of famine
60
Wikipedia
The Dutch Famine Birth Cohort
61
The timing of in utero nutritional deprivation is associated with
different later-life disease outcomes
子宮內暴露與成年後的疾病相關
62
Prenatal and postnatal exposures
could be linked to
phenotypic changes LATER in life.
e line Multiple generations may be affected by experiences during a pregnancy,
Environmental
exposure
vs.orinherited
use several generations
are exposed at
the same time
because of achanges
truly inhernsgenerational, effect. Epigeneticsinresearchers
found both types of effects.
multiplehave
generations
TOP: M.K. SKINNER/NATURE 2010; S. DE ASSIS ET AL/NATURE COMMUNICATIONS 2012
egnant
xposed to
or experiy directly
F0 generchild (F1)
er grandexposed
while its
s a fetus.
perm may
ected by
e, affectd. Transal effects
e in later
s.
Environmental exposures vs. inherited changes in multiple generations
Exposed pregnant female
F1 fetus F2 germ line
Parent (F0)
Child (F1)
Grandchild (F2)
Multigenerational exposure
Exposed male
F1 germ line
Parent (F0)
Child (F1)
Multigenerational exposure
多世代暴露
Great-grandchild (F3)
Transgenerational
inherited effect
Grandchild (F2)
Transgenerational
inherited effect
跨世代傳遞
rational effect of a high-fat diet on breast cancer risk in rats
64
Environmental exposure in multiple generations
Three generations at once are exposed to the same environmental conditions (diet, toxins,
hormones, etc.). In order to provide a convincing case for epigenetic inheritance, an
epigenetic change must be observed in the 4th generation.
65
http://learn.genetics.utah.edu/content/epigenetics/inheritance/
F1
F2
F3
F4
Nature vs. Nurture
毒性反應
疾病
分子機轉???
環境、飲食
基因
68
環境暴露
基因調控異常
基因突變
疾病
69
Bollati et al. Heredity (2010) 105, 105–112
“I don’t want to suggest that genetics and
DNA is not important— it’s just not the
whole story.”
By Michael Skinner
70
The developmental biologist
Conrad Waddington first
defined ‘epigenetics’ in the
1940s as “…the interactions of
genes with their environment
which bring the phenotype into
being.”
Conrad H. Waddington
(1905-1975)
Phenotype: 表現型
Why your DNA isn’t your destiny?
The new science of epigenetics
reveals how the choices you
make can change your genes, and
those of your kids.
Read more:
http://www.time.com/time/magazine/article/0,91
71,1952313,00.html#ixzz2PTYPe63o
2010
72
遺傳學
表觀遺傳學
Genetics
Epigenetics
The alphabet of life
The grammar of life
DNA methylation
Histone modification
Letters of DNA sequence carry the
information
Chemical changes in DNA and in
the proteins to which it is attached
73
Genomics
Epigenomics
Not all genes are active at all times!
74
A single cell develops into a human body
All cells in a human body carry the same genetic information.
75
The epigenome determines what type of cell a stem cell will become.
What is Epigenetics (表觀遺傳學)?
• 定義: heritable changes in gene expression that are not
accompanied by changes in DNA sequence.
• 主要的表觀遺傳機轉:
• DNA methylation (DNA甲基化)
• Histone modifications (組蛋白修飾)
• Nucleosome positioning (核小體定位)
• Non-coding RNAs (非編碼RNA)
• Normal underpinning of development, imprinting,
differentiation and adult cell renewal patterns
• Epigenetics offers an organism a way to adjust the activity
of genes rapidly in response to environmental cues.
76
DNA double helix
腺嘌呤(Adenine)
胸腺嘧啶(Thymine)
胞嘧啶(Cytosine)
鳥糞嘌呤(Guanine)
77
How long is our DNA?
• 人類細胞中一套染色體含有3x109 鹼基對(base
pair)
• 每個鹼基對平均長度為 3.4 Å
• 一套染色體DNA總長度 = 3x109 x 3.4Å = 1010 Å
= 1 meter
埃格斯特朗（Ångström, 簡稱埃，符號Å）
1 Å = 10–10 公尺
78
From DNA to Chromosome
6 folds
40 folds
79
染色體
細胞核
DNA and chromatin
http://www.wehi.edu.au/education/wehitv/molecular_visualisations_of_dna/
81
DNA Methylation (DNA甲基化)
• Covalent addition of a methyl (-CH3) group to the 5 position of cytosines,
usually in a CpG di-nucleotide context in the human genome
胞嘧啶
5-甲基胞嘧啶
DNMT(DNA methyltransferases):甲基化轉移酶
S-adenosyl methionine: S-腺苷甲硫氨酸, 縮寫為SAM
83
DNA methylation and gene regulation
DNA甲基化與基因調控
• Classical example of promoter DNA methylation-mediated
gene silencing:
無甲基化
基因表達
甲基化
基因不表達
84
組蛋白修飾 (Histone modifications)
組蛋白尾端
組蛋白
Lysines (K) in the amino-terminal tails of histones H2A, H2B, H3 and H4 are potential
acetylation/deacetylation, and methylation sites.
A, acetyl; M, methyl; P, phosphate; Ub, ubiquitin.
85
Identical Twins Not So Identical
-- Epigenetic patterns can separate twins over time
Epigenetic differences arise during the lifetime
of monozygotic twins
Mario F. Fraga*, Esteban Ballestar*, Maria F. Paz*, Santiago Ropero*, Fernando Setien*, Maria L. Ballestar†,
Damia Heine-Suñer‡, Juan C. Cigudosa§, Miguel Urioste¶, Javier Benitez¶, Manuel Boix-Chornet†,
Abel Sanchez-Aguilera†, Charlotte Ling!, Emma Carlsson!, Pernille Poulsen**, Allan Vaag**,
Zarko Stephan††, Tim D. Spector††, Yue-Zhong Wu‡‡, Christoph Plass‡‡, and Manel Esteller*§§
*Epigenetics, §Cytogenetics, and ¶Genetic Laboratories, Spanish National Cancer Centre (CNIO), Melchor Fernandez Almagro 3, 28029 Madrid, Spain;
†Department of Behavioral Science, University of Valencia, 46010 Valencia, Spain; ‡Molecular Genetics Laboratory, Genetics Department, Son Dureta
Hospital, 07014 Palma de Mallorca, Spain; !Department of Clinical Sciences, University Hospital Malmö, Lund University, S-205 02 Malmö, Sweden; **Steno
Diabetes Center, 2820 Gentofte, Denmark; ††Twin Research and Genetic Epidemiology Unit, St. Thomas’ Hospital, London SE1 7EH, United Kingdom; and
‡‡Human Cancer Genetics Program, Department of Molecular Virology, Immunology, and Medical Genetics, Ohio State University, Columbus, OH 43210
Edited by Stanley M. Gartler, University of Washington, Seattle, WA, and approved May 23, 2005 (received for review January 17, 2005)
Monozygous twins share a common genotype. However, most
monozygotic twin pairs are not identical; several types of phenotypic discordance may be observed, such as differences in susceptibilities to disease and a wide range of anthropomorphic features.
There are several possible explanations for these observations, but
one is the existence of epigenetic differences. To address this issue,
we examined the global and locus-specific differences in DNA
methylation and histone acetylation of a large cohort of monozygotic twins. We found that, although twins are epigenetically
indistinguishable during the early years of life, older monozygous
twins exhibited remarkable differences in their overall content and
genomic distribution of 5-methylcytosine DNA and histone acetylation, affecting their gene-expression portrait. These findings
indicate how an appreciation of epigenetics is missing from our
understanding of how different phenotypes can be originated
from the same genotype.
DNA methylation " epigenetics " histones
H
uman monozygotic (MZ) twins account for 1 in 250 live births
(1). The origin of MZ twins is attributed to two or more
daughter cells of a single zygote undergoing independent mitotic
divisions, leading to independent development and births. They are
considered genetically identical, but significant phenotypic discordance between them may exist. This quality is particularly noticeable for psychiatric diseases, such as schizophrenia and bipolar
disorder (2). MZ twins have been used to demonstrate the role of
environmental factors in determining complex diseases and phenotypes, but the true nature of the phenotypic discordance nevertheless remains extremely poorly understood. In this context,
differences in the placenta, amniotic sac, and vascularization of the
separate cell masses or even mosaicism in genetic and cytogenetic
Materials and Methods
Subjects. Eighty volunteer Caucasian twins from Spain were re-
cruited in the study, including 30 male and 50 female subjects. Their
mean (!SD) age was 30.6 (!14.2) years (range, 3–74 years). Twins
studied included monochorionic and dichorionic. All subjects, or in
the case of children, the parents, gave their informed written
consent to be included in the study. Lymphocyte cells were purified
by standard procedures and stored at "80°C. In eight cases,
epithelial skin cells were obtained from buccal smears. Muscle
biopsy tissues (n # 14) from the vastus lateralis muscle and s.c.
abdominal tissue (n # 4) were obtained by needle suction under
local anesthesia from volunteer MZ twins from Denmark and the
United Kingdom, respectively. Homozygosity was determined by
using highly polymorphic short tandem-repeat loci. With five
markers, the probability that any twin pair was MZ if all markers
were concordant was 99% (5).
X-Inactivation Analysis. Androgen receptor locus methylation analysis was performed based on PCR on genomic DNA digested with
the methylation-sensitive restriction enzyme HpaII where only the
androgen receptor gene residing on the inactivated X chromosome
is amplified (6, 7).
High-Performance Capillary Electrophoresis Quantification of Global
Histone H3 and H4 Acetylation. Global histone H4 acetylation
(AcH4) and histone H3 acetylation (AcH3) were quantified as
described in ref. 8. In brief, individual histone H3 and histone H4
fractions were prepared from cell nuclei and further purified by
reversed-phase high-performance liquid chromatography (HPLC)
on a Jupiter C18 column (Phenomenex, Torrance, CA). Histones
were eluted with an acetonitrile gradient (20–60%) in 0.3% trifluoroacetic acid using an HPLC gradient system (Beckman
86
Fraga et al. PNAS 2005
Epigenetic patterns separate twins over time
DNA 甲基化
組蛋⽩⼄醯化
組蛋⽩⼄醯化
87
Fraga et al. PNAS 2005
Epigenetic patterns separate twins over time
Green signals: hypermethylation
Red signals: hypomethylation
88
Fraga et al. PNAS 2005
Diet-controlled phenotypes correlate with
unique brain methylomes in honey bees
Ryszard Maleszka
PLoS Biology, Nov 2010
89
90
PLoS Biology, Nov 2010
High-fat Diets In Pregnant Animals Influence Breast Cancer Risk
In Multiple Generations
ARTICLE
Received 22 Mar 2012 | Accepted 10 Aug 2012 | Published 11 Sep 2012
DOI: 10.1038/ncomms2058
High-fat or ethinyl-oestradiol intake during
pregnancy increases mammary cancer risk
in several generations of offspring
Sonia de Assis1, Anni Warri1,2, M. Idalia Cruz1, Olusola Laja1, Ye Tian3, Bai Zhang3,4, Yue Wang3,
Tim Hui-Ming Huang5 & Leena Hilakivi-Clarke1
Maternal exposures to environmental factors during pregnancy influence the risk of many
chronic adult-onset diseases in the offspring. Here we investigate whether feeding pregnant
rats a high-fat (HF)- or ethinyl-oestradiol (EE2)-supplemented diet affects carcinogen-induced
mammary cancer risk in daughters, granddaughters and great-granddaughters. We show that
mammary tumourigenesis is higher in daughters and granddaughters of HF rat dams and in
daughters and great-granddaughters of EE2 rat dams. Outcross experiments suggest that the
increase in mammary cancer risk is transmitted to HF granddaughters equally through the female
or male germ lines, but it is only transmitted to EE2 granddaughters through the female germ
line. The effects of maternal EE2 exposure on offspring’s mammary cancer risk are associated
with changes in the DNA methylation machinery and methylation patterns in mammary
tissue of all three EE2 generations. We conclude that dietary and oestrogenic exposures in
pregnancy increase breast cancer risk in multiple generations of offspring, possibly through
epigenetic means.
Sonia de Assis & Leena Hilakivi-Clarke
Nature Communications, Sep 2012
91
92
de Assis et al. Nature Comm, 2012
Epigenetics and Human diseases
• Human Cancer 癌症
• Neurological Disease 神經疾病
• Autoimmune Disease 自體免疫疾病
• Metabolic Disorders (e.g., diabetes,
obesity) 代謝疾病
• Cardiovascular Disease 心血管疾病
• Gynecological and Reproductive
Diseases 婦產科疾病
• Human Imprinting Disorders 基因印記
疾病
96
Multiple hits to cancer
Genetic gatekeepers
Epigenetic gatekeepers
The Fearon and Vogelstein model
Knudson, Nat Rev Cancer 2001
Jones and Baylin, Cell 2007
基因突變
表觀遺傳變異
98
Epigenetic alterations in cancer
抑癌基因(Tumor suppressor genes) 被甲基化(Methylation)而無法表達且失去功能
99
Ting et al. Genes Dev. 2006
Epigenetic therapy
New understanding of how cancers work is yielding new
treatments
-- The Economist April 7, 2012
100
Science Oct 29, 2010
Stephen Baylin, MD
Johns Hopkins
School of Medicine
Peter Jones, PhD
Van Andel Institute
Jones PA, JCI, 2014
Combined epigenetic therapy with low-dose azacitidine and
entinostat results in objective, durable responses in patients
with metastatic lung cancer
Juergens et al. Cancer Discovery, Dec 2011
自由時報
https://sec.ntu.edu.tw/epaper/article.asp?num=1480&sn=20891
肺癌免疫療法之新篇章
～以去甲基化藥物助攻之伽碼-德爾塔T細胞療法～
肺癌細胞
DNA 去甲基化藥物
Decitabine
I ll
u st
rat
ed
by
Hs
uan
透過 DNA 去甲基化藥物
調控肺癌細胞骨架與表⾯黏附分⼦，促進免疫突觸形成
增強伽碼-德爾塔T細胞精準攻擊癌細胞的能⼒
Take Home Message
• Diet and environmental exposure may have
transgenerational effects through epigenetic
mechanisms, possibly leading to various diseases not
only in exposed people, but also in many generations of
their offspring.
106
課前討論
雙胞胎研究證實了基因的基礎作用，而表觀遺傳學則補充了「環境如
何與基因互動」的機制。兩者共同推翻傳統的「先天vs後天」二元論，
指向更複雜的動態交互模型。 這兩部影片也給了我一些啟發：
1.教育與政策：承認遺傳差異的同時，應重視環境的「調節潛力」。
例如，為高風險族群如家族有心理疾病史提供早期環境介入。
2.自我認知：即使基因設定部分限制，我們仍能透過生活選擇如運動、
減壓等，影響基因表現，這賦予了個人健康管理更大的能動性。
這兩段影片讓我更謙卑地看待生命的複雜性，也對科學揭示的「可塑
性」感到希望——無論是社會或個人層面，我們都有機會改寫命運的
腳本。
References
108
References
109
Thank You