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Induction of Pluripotency: . n' W2 F( d0 H- e2 m3 O
From Mouse to Human8 e7 `, L! F8 y! C/ ^
Holm Zaehres1
0 e8 V0 k: V- |; r) V# W and Hans R. Schöler1,3 E( k1 r7 F3 d1 v3 Q* G. Q
*
. e% n$ x; S6 I. ]1* H6 _ M I" V2 G$ ]; U; F
Max Planck Institute for Molecular Biomedicine, Department of Cell and Developmental Biology, Münster, NRW 48149, Germany
+ J/ Y$ g, u! p1 F$ a, v: K*Correspondence: schoeler@mpi-muenster.mpg.de
9 p+ a. D0 i D# JDOI 10.1016/j.cell.2007.11.020
" r! ?6 C- Z( Y' E% I: wIn this issue of Cell, Takahashi et al. (2007) transfer their seminal work on somatic cell
3 s7 W( X4 _$ rreprogramming from the mouse to human. By overexpressing the transcription factor : ?4 l5 x+ t, t% v2 O; M
quartet of Oct4, Sox2, Klf4, and c-Myc in adult human fbroblasts, they successfully
" c k* G# r9 i8 yisolate human pluripotent stem cells that resemble human embryonic stem cells by all
8 S: J T L* {( j3 G( h, p. umeasured criteria. This is a signifcant turning point in nuclear reprogramming research
2 z/ K6 h1 a8 Q6 r' ?& U* L/ Rwith broad implications for generating patient-specifc pluripotent stem cells for research
" s5 W; q- ^, J9 A/ f, R$ qand therapeutic applications.
l$ M" Z, c4 y7 f5 x& L* gThis year’s three Physiology or Medi-
' L2 t, Y" ]5 ]cine Nobel Laureates—Martin Evans, 1 O: O6 e. P' K4 i1 h8 d
Mario Capecchi, and Oliver Smithies—
4 A% Z4 D9 o8 \7 \- Z. j/ ~will be honored in Stockholm in 10
! t I. t/ v; v5 T. Bdays time for their discovery of DNA
0 a' y; L! i: @* M$ X1 r. grecombination and the development ) b8 O! t' D7 k
of mouse embryonic stem (ES) cell
9 P" f* N, }) ?* E* X Ptechnology. It was Martin Evans who $ P, l, Z3 m. K; p& d: S
discovered how to make mouse ES
' x3 n6 _2 m1 K0 R1 B# D7 r0 Ncells, enabling any genetic alteration ) F' }7 o- d& n8 @1 b0 V2 z
to be transferred to the germline and
) T" H9 o* H3 T7 Q4 @, V: Rhence to the next generation (Evans 8 Q3 K* y9 F9 g9 @. V
and Kaufman, 1981; Martin, 1981).
) z7 O. n2 E* g2 G2 ]3 sBefore this breakthrough, researchers 9 O f* r Y( r9 P) m; P
studied mouse embryonal carcinoma 7 H& j( M& H1 M9 I4 ~- d
cells derived from tumors, which
9 ?& m3 E2 J& S+ e$ `- n7 C9 Tcould form every mouse cell lineage
, {; I! _4 t9 F9 Q' ~except the germline. Combining DNA + n C7 L6 M0 i5 D6 ]6 U
recombination and mouse ES cell
) u- Z' \7 E+ x7 htechnology revolutionized an entire ( h' H$ j; W: B/ L8 t: l9 @
feld of research, forming the basis for
2 B, Y6 l6 ~& H1 zstudying and understanding the roles
# |* N* h; A2 K3 p7 M, A* wof numerous genes in embryonic + j4 Z/ A. h/ E
development, adult physiology, dis-
# Z( w: Y; e( Jease, and aging. To date, more than
. z! [' p5 R. ^9 ?! a# o500 mouse models of human disor-- @" E: W# m' H
ders have been generated. Now, with
1 b( k' O4 k+ W1 S1 f3 _3 g. `! Gthe study by Takahashi et al. (2007) 6 ]# y9 F1 ^( Q. e) I7 ]4 {" M
published in this issue of Cell, another
+ R) p+ w% o: T1 C1 p' x. e6 jimportant revolution is taking place.4 ^( Y3 ^" p9 b6 h
Last summer, Takahashi and
/ S; ?& z, s' \5 V5 U5 DYamanaka (2006) stunned the scientifc - q/ D! h* k. R" h1 y1 c
community with their study showing
5 [3 r8 U" ?$ ]$ G& gmolecular reprogramming of mouse
, h. O0 e# i/ k( O2 {/ g# U3 Csomatic cells into induced pluripotent
7 d; u/ Q; c6 @/ K+ o8 A( l6 x% Lstem (iPS) cells using just four factors:
4 m R8 e9 z# [: m0 ^9 f+ `3 mOct4, Sox2, Klf4, and c-Myc. Their ' G, h7 x" D/ v* v1 C8 U
elegant but demanding approach of
) H8 p! F" a- V6 X; pscreening for a cocktail of factors that , H! W* w) e; r* ?, ~
could reprogram mouse fbroblasts
4 ^+ f7 _, e) { j# I, j' i( [starting from 24 candidate genes paid - y8 q# ~' D& S# Z) O
off with their detailed description of iPS
2 F6 a6 Y0 F5 |0 [cells, which are almost indistinguish-
# j" y" R: u" n5 Zable from mouse ES cells. As with all + u! C4 Q. }. ~% s" G3 _
scientifc discoveries, these exciting ! s8 v+ ~$ ?' }* q
fndings had to be reproduced. Sev-' n) s& } T" _
eral studies published this year not % Q' O2 a- U: W* \! \5 }
only reproduced but also extended : j8 [- }: Z6 }& q
the Takahashi and Yamanaka fndings
8 s: z- N* X" wby demonstrating the pluripotency and - g2 L0 t9 k/ F/ [
differentiation potential of mouse iPS
0 O( ] U, U; `0 Tcells in rigorous developmental assays ' |0 `1 i8 g. c. m/ ~4 [1 u6 u0 ^
(Maherali et al., 2007; Okita et al., 2007; 7 x0 C ^0 @% o" k$ [; S
Wernig et al., 2007). x* x# `$ p# Z
In their new study, Takahashi, , r" A( e8 I: R7 a# W, v
Yamanaka, and their colleagues
2 Y. Y" U; V/ J' X' A9 K/ A(Takahashi et al., 2007) now translate
; _3 h' |) L! |their remarkable fndings from mouse % p& [% ^) c: f8 H
to human (see Figure 1). They selected : W0 C3 u# U" k" y1 A( \
adult human dermal fbroblasts and
6 l1 D% G L# B$ E4 S; T5 _, t# Wtwo other human fbroblast popula-
" v) I! t: c7 h9 Y2 B) E/ p7 ltions (from synovial tissue and neo-; G& B3 I; G4 B
natal foreskin) from different human
. F; M' s/ ^7 p( ndonors as their reprogramming target 4 J0 V z+ c# D q& g9 l
cell populations. They then trans-; b0 P$ c# P% u
duced the human fbroblast cultures
6 x+ k/ z) n7 F# R5 _& A: m6 l8 d! wwith retroviral vectors carrying trans-
- A. ~6 s: ~" { \( w5 E% Sgenes for the human versions of Oct4, l& a) ]: |4 Y) S. e9 Z) {# S+ [: h# V
Sox2, Klf4, and c-Myc and cultured
1 T2 y. B- ?- P6 u# Sthe cells under human ES cell culture
" r5 ^5 [, ^' u1 D5 s, G- Tconditions. Thirty days after transduc-0 ]+ I. p* M9 i1 ]# C1 j$ S7 t( A
tion, the culture plates were covered
. R$ [, x4 t# X: { Mwith human ES cell-like iPS colonies 1 k0 ^7 c, p& z. U( e& b& _
(among other colonies), which could 6 u- E8 T3 k4 \$ ~4 a
be further propagated and expanded.
) z( I Y9 T: ~1 Y% e4 F" {$ yThe retroviral vectors enabled silenc-* f6 W, u- D. H9 l% {
ing of all four transgenes after human # D( s# |7 F8 k5 Y0 S: a7 L3 a# ^
iPS formation (as found in the mouse : P! a! o5 f% ^: g4 K
system) indicating that the iPS cells 6 h; e7 T/ K* | t9 m! b
are fully reprogrammed and no longer
4 \/ M, M5 s0 k! f3 k- T6 m' |! @depend on transgene expression.
7 r6 n5 T% E9 b5 Q, X0 gUnlike the mouse study, human # G( F7 _* s" \
iPS cells were generated without any
1 z$ f$ l9 {3 B2 K& v' G, I. ygenetic selection procedures. Given
* v* E% ^# O g+ Q6 i: Gthe lower mitotic index of human ES
) ^; K/ u' A- k6 i3 w1 K( @/ o2 ^6 ecells, it is not surprising that the gen-
8 g' M- z s/ F9 M3 w% seration of human iPS cells takes nota-
) X3 C* [3 `% l/ f( h1 _" ?- M: rbly longer than in the mouse system.
# t5 T0 X) F4 y v' @. C1 Y% XThe authors subjected their human
R ~3 |& u6 j- Z1 K6 [4 NiPS cells to a panel of assays to com-! S0 u1 `7 B- k
pare them with human ES cells. These
. f) l. E& X; J$ J1 \% h7 F, nassays included morphological stud-# n5 ]5 j; A4 X- F
ies, surface-marker expression, epi-
/ }7 Z0 V( l- _' W. c- ?" B8 Ygenetic status, formation of embryoid 8 R' Z" v9 u+ }2 M) ]) x
bodies in vitro, directed differentia-9 L$ ?! G. ]- \) A4 G) b7 C8 k) }* L" w
tion into neural cells and beating car-
+ I! c" s9 c0 j1 U" y9 kdiomyocytes (according to human % p$ _" ~5 W' z* B
ES cell differentiation protocols), and # F# T' B: T4 u; v; i; P2 `* u" r
fnally teratoma formation in vivo. 5 b3 I S/ V0 G6 S: ]1 o
DNA microarray analysis revealed 4 }0 O8 I1 n) Y; j' s
the remarkable degree of similar-$ N2 m! z. c2 _, I0 z+ a+ z
ity between the global gene expres-: p4 o. V+ q" e
sion patterns of human iPS cells and
3 \1 G" [5 \& G9 R; C1 F( F/ Thuman ES cells. Notably, genomic
/ j, s' r$ _. E+ m2 k7 q3 o3 pDNA analysis as well as analysis of
3 ~4 X% ^ m) h6 c0 H Hshort tandem repeats demonstrated $ q$ ]& D& N0 q7 w7 a0 h. U
the genetic origin of independent " |6 k |; p& K* |
human iPS clones from their parental + n9 n ]; r i' s
fbroblast populations.& b& a+ K5 ~: M' d
The derivation of mouse and then 2 T" w* w \" S$ C3 h. Q) C( g
human ES cells (Thomson et al., 1998)
; l9 Z5 g/ _& G+ x2 K# vas the gold standard of pluripotent 8 X$ F! ~( J# i9 s% E9 C1 _& `
stem cell populations has necessarily
* E: y6 O' K, g( U6 `led to emphasis on differences in the
* ^( g7 F) }. C6 K7 uregulation of self-renewal between
! o8 ?9 N& x/ s5 E, i9 ^mouse and human ES cells. For
- S' ~0 @1 J/ u4 c' X- L/ wexample, human ES cells depend on . [: I, n. G+ I; D8 F% E
bFGF for self-renewal, whereas their 5 a: [6 ~8 N( e8 N9 ]8 |
mouse counterparts depend on the
6 ]3 q( i6 L# e6 m. G9 e( n J( SLif/Stat3 pathway; BMP is involved in " ]+ P4 [& f2 _ J
mouse ES cell self-renewal, whereas
2 m2 e& h0 g) K& ~0 I. L+ |in human ES cells it induces differen-
% w0 B/ S0 K3 A+ d }tiation. Extrinsic factors and signals - C- Z: b5 a B& ^) D3 |
for maintaining pluripotency may dif-
" f H. L4 S; D" q/ R( L0 B( X9 wfer between mouse and human. How-$ l( x, v6 P# A! [" G
ever, the ability to translate somatic
; l6 A0 _2 U2 V; O3 m4 Y$ i' Z, m/ acell reprogramming from mouse to
2 M+ j7 K' Q2 e9 K, x/ Chuman using the same transcription / Q- L4 s9 n# B$ X3 G: Z) k: i( y- m2 t
factor quartet further emphasizes the ! w; D t0 \' H! l0 u/ C1 Q W
conserved nature of the Oct4/Sox2
" D% B$ E z2 U+ ztranscription factor network that
; r. e1 @, a! `, _2 y! Ncontrols self-renewal of mouse and
* ?, v5 E, y. P% i# hhuman ES cells (Boyer et al., 2005).
* W" ?0 a, R' V& T: `- TGiven that Klf4 and c-Myc are chro-$ V, v7 f4 L) B# l2 d* c% O
matin modifers and can immortal-$ E" \0 ^) q, u- ]2 H
ize cells, one might be able to fnd + {+ L2 u8 v: v6 x8 l( J% n
other factors or small molecules that 8 ]; m$ @( D/ R: {9 h( a' B
could replace these two factors in the
n. ]" r4 c" }; W) N* Y! I4 t. Qcocktail (Yamanaka, 2007). In these 6 x; \! m' O* R) z L! s
studies, the possibility of retroviral
. H# X J9 D; s. j0 Iinsertional mutagenesis, resulting + S( Z0 U% o2 \# j: I& u
in the activation of other genes con-! G0 B9 _; A0 u$ u, s
tributing to reprogramming, cannot
+ m# l( m5 W' h% k% H0 J8 cbe excluded, providing an opportu-
0 S5 L- y2 b3 T9 G& C; `nity to potentially identify new repro-
3 p, f" S1 I( J) [gramming factors beyond the cur-2 I$ I! _' e* V
rent quartet. Also, taking a broader
' i. t ?: A. {screening approach for reprogram-2 c, T$ d; S8 T. n( A* t! r: {
ming human fbroblasts (as Takahashi # P/ N: l/ q* y( O' p
and Yamanaka did for their mouse 1 U/ L0 A( v. j
study) might yield other combinations
- b' `+ Q1 K! K: i, c+ a: @of reprogramming factors.
, h4 ^6 s9 s: B# G6 r6 r* vDirect reprogramming of somatic * `; M( n y8 t! T
cells to a pluripotent state, thus revers-
% z6 c9 p }- s6 j% r* fing the developmental arrow of time, & c4 \) m9 m' {2 b
is considered by some to be the “holy
1 d& I% @' D2 Z7 C; Kgrail” of stem cell research. Once the
4 Y" g: q Y; o5 j5 ]1 uresults in human cells are confrmed,
1 y" I4 v7 G$ U1 O$ c `, U8 ?these advances will enable the cre-
1 X$ @) j8 m" p2 r% |9 F" i. Wation of patient-specifc stem cell lines 0 q" J/ X R' m5 y0 J7 g/ j- j
to study different disease mechanisms
/ z9 v- `* ?! d9 O- w/ T! Zin the laboratory. Such cellular models
! \! e& f* @ u `" l: @- w/ p; @also have the potential to dramatically # \' v4 a C, m# i5 o
increase the effciency of drug discov-5 ?- H- l' O& ?0 Q8 v
ery and to provide valuable tools for 1 D: b( E7 W, B$ U6 o% Y" j
toxicology testing. Furthermore, this
: r; z9 @) \2 z/ M7 ?reprogramming system could make 2 g) J/ e9 ?( e$ r! ^; S4 k
the idea of customized patient-specifc
2 Z) S2 ~+ {) l: [screening and therapy both possible ; e7 S6 A8 @$ z0 V7 N+ T
and economically feasible. Finally, the - |% T% U5 \% |# S+ u! L
work will have a powerful impact on 5 x# O. E0 f- H4 Q
the intense debate regarding the moral, 7 K$ a$ c6 `4 t! y) f
religious, and political aspects of ES cell
+ ^+ V+ u' P1 u# l( {$ y2 lresearch. However, a big mistake now * F1 I/ f+ ?* E
would be to consider human ES cells
3 v/ S+ N8 p) O" |" z/ y4 c9 Qobsolete. There are still many hurdles 4 O1 [* Z9 v9 p9 |0 u
to overcome before we ful ly understand + i" N; _$ U: U5 V6 d7 O
pluripotency and before we have human
) a V5 V3 y& t8 PiPS cells in hand that are suitable for
' m3 {# L: r( U; Htherapeutic application. For example, # ]2 `* s: S: G$ z2 R, \- ?
a signifcant proportion of mice derived ) N# Z" M; {0 ?! q% r% }+ i
from mouse iPS cells develop tumors
6 k5 _/ ?4 `# p: i0 ?; hdue to reactivation of the c-Myc retro-
( P2 l3 Z+ d$ k, P- d4 u. _- d/ vvirus (Okita et al., 2007) compared to
8 z: _! S' Z5 V' ~* i9 dmice derived from ES cells, which are
3 F3 K$ g% y# l# L: u: O: Pnormal. The search is now on to fnd a
6 k( t1 C2 o9 ~/ y: P9 b! Qway to reprogram somatic cells without
8 p8 z! h7 l7 \: r0 ^% F E& kretroviruses and maybe even using a 7 F8 g/ F; ]9 H
cocktail of small molecules. Given this,
) X- q" D6 p( t9 A: O4 s( Eit should be emphasized that human
7 }" Y v& J' C# {* z6 M' d. }2 g1 eES cell research is more important than
6 h1 o4 I C& ^/ y. E6 Qever for it will shed light on how iPS
7 a R1 o; P% h0 l: u* scells can best be maintained in their
# C9 U5 O4 F7 _2 dpluripotent state and how they can be 4 L( p) c, c+ y; D8 p
induced to differentiate into the cell
" V3 ~# }# H) s: K+ F# U% Slineage of interest. The feld of nuclear & f3 ~, R# G, [! }! B2 }% t
reprogramming has come a long way
1 }3 q( o% Z _1 Zfrom the initial nuclear transplantation 2 T) i4 m. Q& s }0 C0 G0 i2 D% s
studies in frogs 50 years ago, to the + n# B8 f( f+ i% N# C. U
birth of Dolly, the frst mammal cloned
8 @$ X. @$ }% ?* D2 \$ ffrom adult somatic cells (Wilmut et al.,
: [ ?$ E6 Z3 @+ {: ^ o. m1997), to the fallout from the fabricated
5 \4 ]+ \" C B# Y+ E' K2 ~$ }human nuclear transfer experiments
9 {/ P1 \( ^5 i- n& g1 W; ^ Mof several years ago, to the landmark
! D! }: @9 U+ J* c- F, M9 f6 Lstudies of Takahashi, Yamanaka, and
3 }! E8 p6 a3 N4 D) Dtheir colleagues, frst in mice and now
- u6 M/ F' ~* }5 _in humans." P% M# j' N6 ^ W
ReFeRences" @6 W$ [( [( ?$ {% Z/ i6 e
Boyer, L.A., Lee, T.I., Cole, M.F., Johnstone, ) a4 Q$ ?+ F" |6 X% S2 a% o
S.E., Levine, S.S., Zucker, J.P., Guenther,
4 E8 k& t- Q' t7 @M.G., Kumar, R.M., Murray, H.L., Jenner, R.G.,
- }# c& J- s# F P# t# p) ret al. (2005). Cell 122, 947–956.8 `4 t" S* A. L3 X+ }6 n( W6 g. [
Evans, M.J., and Kaufman, M.H. (1981). Na-& {4 g1 N! u* I! S# M# A Y8 r
ture 292, 154–156.. G& o4 O% q/ f5 C0 H* N5 M
Maherali, N., Sridharan, R., Xie, W., Utikal, J., 2 I$ F$ y. t( ^4 w1 G
Eminli, S., Arnold, K., Stadtfeld, M., Yachenko, 5 {# F% M9 g0 H# j# {
R., Tchieu, J., Jaenisch, R., et al. (2007). Cell
9 O2 S# i" ?8 eStem Cell 1, 55–70.+ ]8 L6 R) o: v( ? a/ d! ]
Martin, G.R. (1981). Proc. Natl. Acad. Sci. USA ( h+ O( x& Z+ \* |9 P3 L7 O
78, 7634–7638.8 S u3 O6 X9 h; c6 P* P, p
Okita, K., Ichisaka, T., and Yamanaka, S.
3 W1 i9 F# W. S. g(2007). Nature 448, 313–317., W5 Q8 ^( x w- R* [) D
Takahashi, K., and Yamanaka, S. (2006). Cell
7 b" {1 U/ h+ F1 }( l" P2 u126, 663–676.- k# b" s- H& A
Takahashi, K., Tanabe, K., Ohnuki, M., Narita,
" F. q3 G* ]" ]M., Ichisaka, T., Tomoda, K., and Yamanaka, S.
8 e2 f3 F5 |! u& I. y2 J1 M& u `(2007). Cell, this issue.1 [8 w* T( \' M k
Thomson, J.A., Itskovitz-Eldor, J., Shapiro, 0 r ^ k$ ` d0 g) q$ J
S.S., Waknitz, M.A., Swiergiel, J.J., Marshall,
( ]# ^6 v; ?3 D3 r( k- RV.S., and Jones, J.M. (1998). Science 282,
+ F1 ~- h7 D3 I# G9 h$ S2 t1145–1147.4 u, [" E" M" j1 H5 q$ J3 q
Wernig, M., Meissner, A., Foreman, R., Bram-# U4 F! p7 z7 q1 L" S
brink, T., Ku, M., Hochedlinger, K., Bernstein,
( M/ P( ]8 h* pB.E., and Jaenisch, R. (2007). Nature 448,
, Y8 F, U3 o7 j8 V, q- f% ]& Q/ |318–324.
9 A1 Q) E2 _* R, C; z: WWilmut, I., Schnieke, A.E., McWhir, J., Kind,
. q4 `$ \( k9 r! b( {4 bA.J., and Campbell, K.H. (1997). Nature 385,
# I7 O X: Z3 c2 K0 r1 x- z810–813.
& g# O' I7 |9 G" C- JYamanaka, S. (2007). Cell Stem Cell 1, 39–49. |
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发表于 2009-4-28 21:35
发表于 2009-5-16 10:41
