|
- 积分
- 0
- 威望
- 0
- 包包
- 4
|
Induction of Pluripotency:
$ g2 K7 p. B6 t) C' RFrom Mouse to Human
9 j; d4 S1 v& Y. O2 c+ L6 RHolm Zaehres1
3 h, @- e+ K3 m- y and Hans R. Schöler1,
: o' O2 u7 f) M$ f' Q6 D*
, [* V: t; ?6 K& o( v$ n6 J1
; G3 q. T; \* D3 ]6 ~2 oMax Planck Institute for Molecular Biomedicine, Department of Cell and Developmental Biology, Münster, NRW 48149, Germany
( C( D% J" v- s0 h! K/ i*Correspondence: schoeler@mpi-muenster.mpg.de' q' k& i, ]! g) Q' G. t
DOI 10.1016/j.cell.2007.11.0204 w; v$ S/ O" G! i
In this issue of Cell, Takahashi et al. (2007) transfer their seminal work on somatic cell
8 c. w. t& q# Zreprogramming from the mouse to human. By overexpressing the transcription factor
% Y6 H) b& `9 N) }$ o- Qquartet of Oct4, Sox2, Klf4, and c-Myc in adult human fbroblasts, they successfully ) u* \ F& O- l' \
isolate human pluripotent stem cells that resemble human embryonic stem cells by all
- E" h' O: Q9 qmeasured criteria. This is a signifcant turning point in nuclear reprogramming research 1 ^3 b [4 j6 e0 G+ U3 n8 f* x7 l
with broad implications for generating patient-specifc pluripotent stem cells for research 6 G; r! U+ R2 ~; P9 x4 i: f
and therapeutic applications.( |6 e9 R9 u% T
This year’s three Physiology or Medi-% T0 y/ v( I$ {# z/ z3 w/ q
cine Nobel Laureates—Martin Evans,
& N* T+ j0 T3 K% Z! t3 J/ lMario Capecchi, and Oliver Smithies—
0 C% \+ E0 y2 h& Gwill be honored in Stockholm in 10 # ?! R4 T% ]/ M- w
days time for their discovery of DNA
2 X* X# g: w# X6 m3 g8 {* rrecombination and the development $ y1 ?! V5 h# k3 I( R
of mouse embryonic stem (ES) cell 0 _6 b+ D- x1 K0 c% @& }
technology. It was Martin Evans who
! `1 q& v$ Y) `) k$ Q5 m0 hdiscovered how to make mouse ES
- V: x- A0 C3 d8 S& x% F& g. ncells, enabling any genetic alteration 4 ?' H" b* B2 o( V0 j3 }
to be transferred to the germline and
0 O) P* N/ H* F j- r- bhence to the next generation (Evans 5 R" S2 F/ \" d+ P
and Kaufman, 1981; Martin, 1981).
: P% W N9 D! J7 o( p( c7 {Before this breakthrough, researchers
7 `4 Y9 k3 ~8 x: D& A5 @studied mouse embryonal carcinoma
& D1 v) M% a% V& hcells derived from tumors, which 8 q4 K2 e$ v' S8 @, S5 s0 w% R' N
could form every mouse cell lineage " G) A$ s5 ]3 x, i, o- j2 X/ L
except the germline. Combining DNA , U, v, ~& N; g3 W0 m
recombination and mouse ES cell
' R; F* L/ G! [" ^0 n3 Ntechnology revolutionized an entire
8 X1 h- ^, Z* Jfeld of research, forming the basis for
" h7 H& [; r a4 t. H" dstudying and understanding the roles ; w' l- t4 w! L G
of numerous genes in embryonic $ r' T$ V7 M4 D0 X) ~ N6 K
development, adult physiology, dis-
0 R6 a1 O7 j5 q" Jease, and aging. To date, more than
3 s2 p/ l; \. N; W+ |500 mouse models of human disor-
! @ z9 s: A/ x$ M' T) Gders have been generated. Now, with
! q' q2 r7 h- M- z1 _2 _7 lthe study by Takahashi et al. (2007)
$ K' ^- A9 h3 R8 }# l+ \9 s6 \6 N$ ?published in this issue of Cell, another
3 r5 t! [! n! Z3 R8 Limportant revolution is taking place.
0 W9 g$ p4 }% y, o3 b8 gLast summer, Takahashi and ' T) k) U$ f; w
Yamanaka (2006) stunned the scientifc . N4 u( p9 q/ z! _& p# S2 j- \
community with their study showing
6 i( [& X- V3 V, l) N* wmolecular reprogramming of mouse
1 n9 W) g2 \' P, W! N @somatic cells into induced pluripotent
G4 h; u3 N# U; ?stem (iPS) cells using just four factors: * d3 T3 w0 g5 j% d
Oct4, Sox2, Klf4, and c-Myc. Their
y# X% A9 @2 Z t, w, Belegant but demanding approach of
5 Z! ]" x6 ~: m% o" d2 C2 mscreening for a cocktail of factors that
0 F4 q! K5 l2 a$ t& C# Fcould reprogram mouse fbroblasts
) _/ v' J% f/ Z, \7 Astarting from 24 candidate genes paid 4 V; h- ^1 u0 h r1 C
off with their detailed description of iPS
9 L% D( y2 q2 |0 }5 @% Q+ }9 ?cells, which are almost indistinguish-
1 p9 ~" T' t3 `* \/ j. V& dable from mouse ES cells. As with all
& F" z9 F' Z3 n6 e( M. oscientifc discoveries, these exciting , {; V( V0 H$ U1 j. g
fndings had to be reproduced. Sev-- a/ f' E; a- Q1 I4 n6 q) r
eral studies published this year not 0 k$ f+ p$ w' {0 x1 x
only reproduced but also extended 8 j3 i; S( h( F8 R/ O
the Takahashi and Yamanaka fndings + G" O4 G- D# E* H9 m3 O
by demonstrating the pluripotency and
$ K/ y/ e1 ]3 @differentiation potential of mouse iPS
# v/ K6 W3 Z9 u* r% Kcells in rigorous developmental assays
* S1 B' O/ c6 g(Maherali et al., 2007; Okita et al., 2007;
0 v/ L: P+ o' l; b/ HWernig et al., 2007). w9 c' N+ d9 {, t7 ]- S9 g$ {- b
In their new study, Takahashi,
! l2 c1 R1 M% m' b" ]; [Yamanaka, and their colleagues ) E3 Q# T. x( o+ w4 p" }% O
(Takahashi et al., 2007) now translate
- c: o# E8 U7 w* j3 ptheir remarkable fndings from mouse
0 G. v* W5 g. }8 \. e5 Z$ l( vto human (see Figure 1). They selected / N9 ~& |. _, Q( ` p
adult human dermal fbroblasts and / }; j. c: `7 W9 \8 w' W
two other human fbroblast popula-, [8 _* ?0 W, R
tions (from synovial tissue and neo-
2 J& u! ~/ c T% t7 y0 }4 Nnatal foreskin) from different human $ e3 o$ M, {4 @3 s& z- C9 E2 h
donors as their reprogramming target # q( O$ L' [! F6 q, c5 ?
cell populations. They then trans-
" W. @3 c, ?* ^! Q7 T; H Nduced the human fbroblast cultures
3 A4 T$ y1 U2 n1 `with retroviral vectors carrying trans-: B, ^* s3 M8 [( q
genes for the human versions of Oct4, 3 R! W, a- A6 h1 F
Sox2, Klf4, and c-Myc and cultured 4 l6 J8 z5 ?! D, Q
the cells under human ES cell culture
7 P6 I' `3 b( u2 L- {" g8 Sconditions. Thirty days after transduc-
6 \, g* Y; X3 d! ition, the culture plates were covered - k2 h0 A+ ~5 c7 v, O8 E9 L& x/ K% F
with human ES cell-like iPS colonies
/ p! X6 k7 Y" Q- Q5 d(among other colonies), which could ; {3 b9 O/ Q4 e
be further propagated and expanded.
2 @1 `% c' A# s: B5 qThe retroviral vectors enabled silenc-+ u0 I t% _6 o; c& |: q" b' n3 Z
ing of all four transgenes after human - e( k, r7 u; ~$ |7 O: E$ _; y/ h
iPS formation (as found in the mouse 0 R$ g* F0 O! B3 y$ D4 v2 r
system) indicating that the iPS cells
6 J- Q0 O& O4 P7 e- b$ `! Dare fully reprogrammed and no longer ( x! N9 v/ @* F% ]/ C h! }9 l
depend on transgene expression., @6 M3 k) F5 t2 @% a) [. ~
Unlike the mouse study, human 6 L; a* j& s: V
iPS cells were generated without any
% R' D9 s7 l- T1 Z& g, L5 x2 w6 H5 Pgenetic selection procedures. Given
4 }( x7 H- g# Ythe lower mitotic index of human ES
# t3 h0 ]; |. K: Wcells, it is not surprising that the gen-0 t" [ g) v* A4 u6 A% ]" _
eration of human iPS cells takes nota-9 W" }% q! ~0 {/ I, o
bly longer than in the mouse system. " x! n8 x3 J K! V m6 Y$ @
The authors subjected their human
- T' d2 i, c# @( _$ D( WiPS cells to a panel of assays to com-
4 {# ~- i' y' L( t/ n X% Fpare them with human ES cells. These ) C* R8 Q! x& K( k% U9 ?8 Z; }
assays included morphological stud-- x8 w( ?* o5 }
ies, surface-marker expression, epi-( l4 o0 ?+ h7 p
genetic status, formation of embryoid
9 k: s1 L3 m: u6 p( O4 qbodies in vitro, directed differentia-
D' K& T: c, B6 S) b3 Otion into neural cells and beating car-9 r- }: B# D) E( l% H7 K4 n
diomyocytes (according to human ' h% E( h0 `1 C+ g6 [; s1 h
ES cell differentiation protocols), and $ |7 s. i! ` K% C
fnally teratoma formation in vivo. 8 l4 B1 R3 Q( Q0 f" _1 t7 z r z# Z
DNA microarray analysis revealed
2 v9 L0 b7 k( ^% Nthe remarkable degree of similar-& W' ]; t! D& Y; [+ o+ J w9 |
ity between the global gene expres-
+ j4 S; n, Y' L0 tsion patterns of human iPS cells and % L; k" d/ W8 d" a
human ES cells. Notably, genomic $ {% i; B' z& A: g
DNA analysis as well as analysis of - O3 e a2 \2 c% F
short tandem repeats demonstrated 9 P: {% ^0 S1 K$ h" }
the genetic origin of independent
0 h8 S) J8 `7 G% o2 Y/ m# n! Uhuman iPS clones from their parental " z6 M; ?% u7 p' I6 D% r, R
fbroblast populations.
4 n3 N0 K7 o3 U7 U. hThe derivation of mouse and then
3 @* |; c# |3 p; ?; E9 Jhuman ES cells (Thomson et al., 1998) * N0 h2 }1 e: Q q3 B) H/ R7 Q5 {( ^; [
as the gold standard of pluripotent
# `- o6 C& W- [2 o+ s5 bstem cell populations has necessarily
0 P; ?7 d9 n# _9 M! g5 M2 Lled to emphasis on differences in the 7 I6 D& T* [* ~6 w
regulation of self-renewal between
/ f3 E; N3 s/ z3 f8 I9 X' zmouse and human ES cells. For
" \$ U) Y& E7 E lexample, human ES cells depend on 0 x1 b, Y& x1 E) U/ r
bFGF for self-renewal, whereas their : ]7 L/ d7 G, s5 ~3 I7 Q$ G$ W
mouse counterparts depend on the " N- \! S9 b+ n- V4 @$ H7 P- r
Lif/Stat3 pathway; BMP is involved in
# s$ Z% f. v$ Y. Fmouse ES cell self-renewal, whereas 3 Y- `) j p8 _0 o1 q* _
in human ES cells it induces differen-; Y" i# z' M4 @
tiation. Extrinsic factors and signals % z1 V; T4 h; U* w
for maintaining pluripotency may dif- r! Q2 d) j6 E1 f: t
fer between mouse and human. How-
* B1 Y& e4 l" _3 Jever, the ability to translate somatic
. u: t- K" `0 w. S$ t' Rcell reprogramming from mouse to
. y: i$ y/ `8 ihuman using the same transcription
1 Z- S5 Q6 o; Z& X! yfactor quartet further emphasizes the 9 \8 C% j; j6 ?4 W$ D/ G9 K* p
conserved nature of the Oct4/Sox2 % E) A6 u* u; _$ h8 o. l
transcription factor network that
l, O) I. \/ L7 i' Acontrols self-renewal of mouse and
; H, u) y. Y; q2 a3 q5 {4 Nhuman ES cells (Boyer et al., 2005).
; M; I2 q" H0 z% s1 @Given that Klf4 and c-Myc are chro-9 N1 t, ?7 \% P$ U+ }: y
matin modifers and can immortal-
7 X3 y8 X' e7 n$ Q, K/ i* o0 xize cells, one might be able to fnd 6 D: L$ p! t$ D6 |: N
other factors or small molecules that
" [5 q; Y5 R/ ]3 xcould replace these two factors in the % z U9 ]6 {$ e
cocktail (Yamanaka, 2007). In these
3 n' f4 [( K2 {' fstudies, the possibility of retroviral
" X( |1 R3 D6 E$ f dinsertional mutagenesis, resulting f9 v5 B! H1 f+ b8 M6 P1 X- n' g6 x4 ?
in the activation of other genes con-3 c8 E6 c+ I% I( S2 } U3 c* h
tributing to reprogramming, cannot
/ r0 W8 s3 ]$ k7 d9 Nbe excluded, providing an opportu-/ m! R9 d& ?& R" r( `
nity to potentially identify new repro- X5 o! F" k q& R ~
gramming factors beyond the cur-6 ^7 M# O+ [# i; z6 Y
rent quartet. Also, taking a broader ! f, [$ x1 L5 l) s$ p/ x6 S$ X( Z
screening approach for reprogram-
. @6 E! O, w% N* K9 T6 \7 q. K. `ming human fbroblasts (as Takahashi
% n7 M6 Q% u. b/ Fand Yamanaka did for their mouse , X4 i: C2 f& ]! c- ]; h: P
study) might yield other combinations 9 Z% G# i3 p4 x5 P, C5 b8 }
of reprogramming factors.1 B% Y6 W3 @( E1 p: G5 p
Direct reprogramming of somatic & B$ d* \! j" ^) k" B# U0 B0 H
cells to a pluripotent state, thus revers-
, ^9 i5 I4 e9 J& \ing the developmental arrow of time, ' c/ y2 v) G( @+ i' Q- [
is considered by some to be the “holy
- O" F! C/ r" E2 z4 k9 H: P3 Tgrail” of stem cell research. Once the ) _1 O- a+ l/ p9 I- I
results in human cells are confrmed, }0 h$ m$ d, M. ]
these advances will enable the cre-
0 U( S |- ~2 M6 i! Gation of patient-specifc stem cell lines 4 `9 t8 ]: n% E( m1 @
to study different disease mechanisms
; h$ d' v0 O" _9 C; ?3 n" min the laboratory. Such cellular models
! E* K3 q% B6 E) R" y8 malso have the potential to dramatically : d; O9 ]4 @0 D* n3 D
increase the effciency of drug discov-
- r% |* g; \7 x* @ery and to provide valuable tools for
j& c8 t1 v0 c1 B" L8 z8 d, Ztoxicology testing. Furthermore, this
5 j5 O) m4 y+ Vreprogramming system could make 9 G/ w0 j7 c% X& K- k9 R5 q" x6 F" o
the idea of customized patient-specifc 7 E* J0 w* g1 j& P/ C% \$ B
screening and therapy both possible
1 E8 Y0 A: S# D+ v" e9 C5 Band economically feasible. Finally, the % p/ ]- ]& `! }
work will have a powerful impact on 5 @0 u z2 y4 p% {, t
the intense debate regarding the moral, $ `( ]4 a& g6 O) \0 {7 E
religious, and political aspects of ES cell ! v9 `8 V) H" U8 q' w2 M
research. However, a big mistake now 9 W, I& ]8 G* Y4 f- b
would be to consider human ES cells
, Q/ m; a: F4 `7 k0 b0 {obsolete. There are still many hurdles ! p% s# {) R) D3 W9 K
to overcome before we ful ly understand
0 i3 d, O# H4 ?0 Upluripotency and before we have human / P$ c+ ]# @+ Q1 h( H8 G) }
iPS cells in hand that are suitable for
* I9 M2 a& s1 v. Htherapeutic application. For example, , z- g0 N2 A/ D
a signifcant proportion of mice derived ( @7 X) d8 k$ j& d: [8 @- ]3 o
from mouse iPS cells develop tumors ( {! R7 J: `- `
due to reactivation of the c-Myc retro-
0 N6 a* N( ]5 f% e( r' v+ |virus (Okita et al., 2007) compared to % _& H; \1 b' [
mice derived from ES cells, which are
1 H& T& n. i: r3 _* M2 X# Cnormal. The search is now on to fnd a
/ |( f1 f6 p: @- B$ Z5 R$ Mway to reprogram somatic cells without 8 ?$ X* g+ r( _' C
retroviruses and maybe even using a
% h( Z& O4 ~) a! B* Lcocktail of small molecules. Given this, 0 P1 W9 G& [8 l
it should be emphasized that human
* \" @ u& `) K* F0 o$ `6 _ES cell research is more important than 4 z3 \+ ~$ U. b% A3 L: Z) W
ever for it will shed light on how iPS
# _3 h. n( m% b, U9 ?# s6 o4 ]cells can best be maintained in their * N, n4 d6 x+ m2 U0 H. A2 Q6 n9 Z
pluripotent state and how they can be 1 Y+ q- `$ _) A& {/ m
induced to differentiate into the cell
5 Z2 J7 ^$ e6 p7 ~+ ]/ }" Alineage of interest. The feld of nuclear % M y9 t9 l9 {. V
reprogramming has come a long way t+ i5 k+ Z1 X' u2 }6 q+ `5 ]
from the initial nuclear transplantation 6 ~' C8 h* l/ Z! K; b
studies in frogs 50 years ago, to the
6 o$ Z0 ~9 E3 l; v' Ubirth of Dolly, the frst mammal cloned / E; N. c5 F+ c
from adult somatic cells (Wilmut et al.,
/ M7 w9 s0 L4 t$ U6 ?1997), to the fallout from the fabricated
& A8 C2 k) B9 g6 a9 M Whuman nuclear transfer experiments ) i1 c; Z A8 U ]% G6 r
of several years ago, to the landmark ! a2 y; _/ H) G1 g- @# b5 C
studies of Takahashi, Yamanaka, and . Z0 ?" [. x e/ G
their colleagues, frst in mice and now
! v2 G) \( {5 G7 k [* m- d# h( min humans.& y! c2 n4 Z! a) e. `8 Z
ReFeRences8 y; f. k; w0 H6 y5 u6 s: Z" Q
Boyer, L.A., Lee, T.I., Cole, M.F., Johnstone, # Q2 b" m1 a$ D8 f
S.E., Levine, S.S., Zucker, J.P., Guenther,
w/ }+ r& P! B) E1 w* r8 m# xM.G., Kumar, R.M., Murray, H.L., Jenner, R.G.,
2 t' }' C/ C5 y8 k* o5 ^: Q/ l2 Det al. (2005). Cell 122, 947–956.
( d% S* f0 |$ A0 PEvans, M.J., and Kaufman, M.H. (1981). Na-& ~4 w( ?, \" ^, [
ture 292, 154–156.
6 d8 K' v2 Y. Q2 VMaherali, N., Sridharan, R., Xie, W., Utikal, J.,
+ C" o; ]8 m. F( ~. X& KEminli, S., Arnold, K., Stadtfeld, M., Yachenko, * }% X' T; {/ \ z8 H* Y
R., Tchieu, J., Jaenisch, R., et al. (2007). Cell ( t. h3 k# h1 C" A
Stem Cell 1, 55–70.. u' P& S0 g7 H
Martin, G.R. (1981). Proc. Natl. Acad. Sci. USA 4 M! |: B w$ Y
78, 7634–7638.+ J2 E9 N" q( z$ I( r& v8 y1 b/ d6 N$ G
Okita, K., Ichisaka, T., and Yamanaka, S. : K, X, c' \2 j& {% n5 F" _; \% @( f8 w
(2007). Nature 448, 313–317.
! k/ x: V9 l, B9 N0 _8 m) W3 UTakahashi, K., and Yamanaka, S. (2006). Cell 1 G& ^* d% r) V' W4 T! [
126, 663–676.
( P k" w+ ]- W3 A; ^5 W# p) t3 ?- KTakahashi, K., Tanabe, K., Ohnuki, M., Narita, 3 x0 h" d% R" D
M., Ichisaka, T., Tomoda, K., and Yamanaka, S. 6 _4 {' |" [ q$ v$ ?) o
(2007). Cell, this issue.
/ f$ S+ K4 F, |+ S$ LThomson, J.A., Itskovitz-Eldor, J., Shapiro,
; O# z; B7 ^1 }2 xS.S., Waknitz, M.A., Swiergiel, J.J., Marshall, 5 m% h) \/ K, t0 G' G% W/ A
V.S., and Jones, J.M. (1998). Science 282, # x5 p+ }3 u) N! M5 q
1145–1147.3 F' ]) t0 W0 N% A) ? z6 }/ r
Wernig, M., Meissner, A., Foreman, R., Bram-. I8 z5 Z. e) F! t/ d3 K3 }/ B8 U
brink, T., Ku, M., Hochedlinger, K., Bernstein, ; H/ a- s# g% g' @
B.E., and Jaenisch, R. (2007). Nature 448, + h. h* d7 y- n# X) E! ~6 E7 p- D* X
318–324." ` X+ ~! _ |# J
Wilmut, I., Schnieke, A.E., McWhir, J., Kind,
* d* N) S' F: z+ h, X. |A.J., and Campbell, K.H. (1997). Nature 385, 1 g9 l* C# [$ t" ?5 d$ z1 l$ V; Y
810–813.5 `6 C G% G) Z
Yamanaka, S. (2007). Cell Stem Cell 1, 39–49. |
|
发表于 2009-4-28 21:35
发表于 2009-5-16 10:41
