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Induction of Pluripotency:
+ B2 W# W: x/ [# N' D9 tFrom Mouse to Human3 L1 o/ x$ f8 o( c' V) @6 Z
Holm Zaehres1* h! Y/ N* u" g! O# b( O
and Hans R. Schöler1,# z1 J. h% j3 V% Z: f. R, Y; n8 |
*9 } x* O5 I4 ?( @* ?
1) ?- [8 J" p& g
Max Planck Institute for Molecular Biomedicine, Department of Cell and Developmental Biology, Münster, NRW 48149, Germany
4 o* F3 M5 X9 p, u*Correspondence: schoeler@mpi-muenster.mpg.de$ o6 F. O9 t+ X/ ^! C3 k
DOI 10.1016/j.cell.2007.11.020
3 w4 X, k) a+ N# BIn this issue of Cell, Takahashi et al. (2007) transfer their seminal work on somatic cell # J5 p' A. ^+ ?( ^+ L
reprogramming from the mouse to human. By overexpressing the transcription factor 5 U) _* }, e$ O9 [ a5 l _
quartet of Oct4, Sox2, Klf4, and c-Myc in adult human fbroblasts, they successfully , c3 a [) g2 B( a; ^7 i, {7 t
isolate human pluripotent stem cells that resemble human embryonic stem cells by all
. ]% M, A- E6 M# ~$ Z* dmeasured criteria. This is a signifcant turning point in nuclear reprogramming research
% T$ C2 D4 c5 @+ I4 x' B3 K b2 ^with broad implications for generating patient-specifc pluripotent stem cells for research % L6 ?; m) z, m {
and therapeutic applications.
2 d5 p) |; j0 o0 a3 i. D0 S3 \" ^5 DThis year’s three Physiology or Medi-+ m3 k8 t, W$ q
cine Nobel Laureates—Martin Evans, 3 j' [: ]6 l4 b* e! V8 X% v
Mario Capecchi, and Oliver Smithies—* {1 n- z) s1 W# r8 m$ D+ x2 k; _ k
will be honored in Stockholm in 10 " x& j1 O4 g4 o$ s
days time for their discovery of DNA 4 R4 l8 ~' `* x& I
recombination and the development
2 m4 x. Z2 e' v# r7 D! Bof mouse embryonic stem (ES) cell 3 M$ K# t6 E" u6 o
technology. It was Martin Evans who * u. [3 n2 C+ s- T+ b
discovered how to make mouse ES * y0 m* H+ n' L, p' m+ e
cells, enabling any genetic alteration 8 B8 i3 ]3 ~. p9 I. d) f
to be transferred to the germline and " g0 B7 u o: x4 O. r" I9 s4 K u$ \
hence to the next generation (Evans - @+ M& N2 \; B# n9 T |9 ?$ i
and Kaufman, 1981; Martin, 1981).
% C/ o v. i3 }* BBefore this breakthrough, researchers / d: o6 ?- K5 L( a5 i
studied mouse embryonal carcinoma - M2 ]* ]5 ?4 c; \' ^2 o: f
cells derived from tumors, which . p6 {" E- G8 u- l
could form every mouse cell lineage 4 J& W* Z3 k4 m, V& m8 w( c# Q
except the germline. Combining DNA
; B6 o3 m0 X, k& z8 e4 Irecombination and mouse ES cell ) K+ J/ l' P# ~
technology revolutionized an entire
% E* w I, X6 ~. E9 `feld of research, forming the basis for
/ v" l/ c; `# `9 R& E; }9 y5 r! hstudying and understanding the roles ! D6 {/ D2 c/ U1 h ?- V2 o+ s3 V
of numerous genes in embryonic
/ d6 S: Q7 Y/ q: O O/ s3 q% `$ odevelopment, adult physiology, dis-
" Y, B a4 _; k1 b5 }' Aease, and aging. To date, more than 0 t% t( L. D1 o8 I
500 mouse models of human disor-
. r8 V( b2 b4 r+ o* x4 tders have been generated. Now, with
: ^ n6 Q: u- K Z T! I5 othe study by Takahashi et al. (2007) 7 P6 i8 I) B2 I1 M" E# q* J- x2 M
published in this issue of Cell, another
6 k, |3 H, Z, G9 U' w/ L* C3 V/ {important revolution is taking place.: m% u3 V! H5 d
Last summer, Takahashi and ! J$ ^1 V3 t( u) t3 G. w+ R
Yamanaka (2006) stunned the scientifc
) a, r& Q( J4 _8 I G; E( jcommunity with their study showing 1 W N. m0 p0 v1 k9 H
molecular reprogramming of mouse 7 u, s8 P$ Q L* s
somatic cells into induced pluripotent ; z1 U, l' g. U5 i$ |
stem (iPS) cells using just four factors:
+ y) ?9 w0 r$ t5 z7 ^$ j ^# XOct4, Sox2, Klf4, and c-Myc. Their
U9 j8 H( V8 G. Y Q4 M5 w% D( oelegant but demanding approach of
) Z1 ?# @. a, Wscreening for a cocktail of factors that
/ f- _" l2 w2 V1 @0 jcould reprogram mouse fbroblasts
6 Q0 F9 A, u) h5 Y" Z/ Hstarting from 24 candidate genes paid 8 a; }( `" C1 _& x B8 q3 a
off with their detailed description of iPS
: W6 d7 C6 s' z4 qcells, which are almost indistinguish-
" ?0 Y4 @2 U' r+ ^/ P5 oable from mouse ES cells. As with all & ~! p' R6 h& W) Z
scientifc discoveries, these exciting
; C' ]. ~8 N6 `" efndings had to be reproduced. Sev-
0 b# H4 A% l1 ?- ^8 j% Q" Neral studies published this year not + x+ l2 a8 ]1 c/ [" n) a
only reproduced but also extended
6 S) E; q- h, G. j" r+ ^the Takahashi and Yamanaka fndings 9 I8 A5 Q; m3 [, r
by demonstrating the pluripotency and * c/ A/ I2 d0 N$ X+ s/ }5 Z! D
differentiation potential of mouse iPS 0 [" Y0 x# `8 `
cells in rigorous developmental assays
0 L4 w- O2 A. ~( W9 c(Maherali et al., 2007; Okita et al., 2007;
2 p; M7 I* w/ a( E7 ~Wernig et al., 2007).
" x( |+ `! _' i/ h! p% MIn their new study, Takahashi,
! Z+ S" J2 S* r9 F1 M! ?Yamanaka, and their colleagues ' O. x: ?9 Z* F
(Takahashi et al., 2007) now translate
; L$ D) d/ I! r$ l: z+ Dtheir remarkable fndings from mouse ) O0 |" _& Q2 P1 p7 r9 S1 t# K8 B' O/ z
to human (see Figure 1). They selected
; F% x- O/ E; b( ~% madult human dermal fbroblasts and 1 u. w0 ]2 n. @. ^. G1 _9 t
two other human fbroblast popula-
s* h- a( x$ ^tions (from synovial tissue and neo-7 O1 A' A' l7 Z6 i5 g
natal foreskin) from different human
: y, M0 ~8 c) v7 ~+ Y4 b, P9 ~donors as their reprogramming target
6 {6 E% x* A' H) c( lcell populations. They then trans-
: _" P3 E# X4 t: ~, L; bduced the human fbroblast cultures
: U& q% J4 P: z/ v0 _1 t" Xwith retroviral vectors carrying trans-
# P' U2 N% U& r' d$ o; Lgenes for the human versions of Oct4, . e$ ?; U: P7 s: l
Sox2, Klf4, and c-Myc and cultured
5 x; L$ q' u% H( U) lthe cells under human ES cell culture
3 a0 |; |+ q/ B$ U( _conditions. Thirty days after transduc-
3 \; G8 m5 ~" c- u/ c0 S, V: btion, the culture plates were covered % Y3 u2 b. v) H" ]
with human ES cell-like iPS colonies $ R# v( X* |% l7 X
(among other colonies), which could
# Y5 }; W; ]# B: \3 T( Jbe further propagated and expanded.
" {- ]! e4 Z# M$ d# j; j) ]! ?The retroviral vectors enabled silenc-
6 ~8 n: g& R4 H7 _! f' `% |/ Ving of all four transgenes after human
% l* M. F( L6 b1 x9 ?+ AiPS formation (as found in the mouse % e3 J' U4 F, o# C$ i- j, v
system) indicating that the iPS cells * J: h% y# ?0 r% l, M' W& z2 m# M5 B
are fully reprogrammed and no longer % g8 u% P" d* V( B. }
depend on transgene expression.
~6 K2 ?" v1 MUnlike the mouse study, human
" o1 }: e7 w5 ^# X" riPS cells were generated without any ' w3 U1 i7 H2 H8 i6 g( a6 ]
genetic selection procedures. Given
: Y$ [$ c8 C3 w) U v2 _the lower mitotic index of human ES 0 B* H; w; S1 e' C7 s/ p
cells, it is not surprising that the gen-
7 \. C o L8 c( n+ O$ T( |eration of human iPS cells takes nota-( [7 c1 q; p1 j1 x! N9 Q8 R6 g
bly longer than in the mouse system. * Z4 g0 ^) U' k ~
The authors subjected their human
$ f: S9 G( l/ `( \iPS cells to a panel of assays to com-
, N8 k' s$ V# ^3 p _ ~+ zpare them with human ES cells. These 9 I! p% V- y! w1 O+ S1 Y' F) v
assays included morphological stud-/ H2 ?0 i9 {4 }$ N) }0 j+ a/ S
ies, surface-marker expression, epi-' V( H( ^$ c* E1 f
genetic status, formation of embryoid
$ d& I7 @9 i+ l- d9 Y; W7 {* X7 t# pbodies in vitro, directed differentia-' ^/ \$ h) H4 e4 l/ `4 o
tion into neural cells and beating car-
k b. M E& M/ G2 Mdiomyocytes (according to human
) `6 z( f o' W& L! }ES cell differentiation protocols), and
& {, }- e; |& H) z& U3 F8 Z3 Hfnally teratoma formation in vivo. 8 T3 \( V6 D4 U: I$ `
DNA microarray analysis revealed ; w- {9 H4 q+ j
the remarkable degree of similar-
# n4 M& I3 |$ ~( G# D! Qity between the global gene expres-) Y1 f2 M* p/ Y+ R& N
sion patterns of human iPS cells and
/ D* {$ z0 r. @' w H2 D7 mhuman ES cells. Notably, genomic + J7 @: f7 X" Z$ r
DNA analysis as well as analysis of 5 k1 R& `- ^4 i4 k/ r
short tandem repeats demonstrated 6 j3 m* Y y; K# r
the genetic origin of independent " @8 |+ p8 n- P: X' f
human iPS clones from their parental 6 o. Q; A( K* L) [* @" E
fbroblast populations.1 R+ \( \- U: X( y5 f* W1 c
The derivation of mouse and then
. g/ B9 U& X) y* Shuman ES cells (Thomson et al., 1998) 9 S( C$ E* k5 _/ l* x2 ?
as the gold standard of pluripotent
8 K0 q" H3 \" f. Istem cell populations has necessarily
& T, N7 z+ T+ F& U/ Dled to emphasis on differences in the
8 E2 n8 z' e8 A- s$ H7 Zregulation of self-renewal between * f$ h, r* F: D5 A2 H
mouse and human ES cells. For 9 X6 N: _1 p+ ^! a9 T
example, human ES cells depend on
: p. v' i! ?# y; j3 j0 ?bFGF for self-renewal, whereas their 7 |* q7 E* ~' O* w- c) _) e1 T6 {, Z
mouse counterparts depend on the
- B- J7 p6 T4 ?& \2 {- H# FLif/Stat3 pathway; BMP is involved in 8 R9 a, r0 s* y% C: S, R
mouse ES cell self-renewal, whereas
" e. y) z, F2 ^5 G) f: ^* {in human ES cells it induces differen-
% R5 C$ m5 N6 v& D8 Y# J! \$ ttiation. Extrinsic factors and signals ( ^$ l1 X+ X6 B- l- `- S
for maintaining pluripotency may dif-3 k3 ~! w9 I$ c( w( s/ Z7 K I
fer between mouse and human. How-9 Y' q8 x& O. @
ever, the ability to translate somatic
# Y# i2 R+ M A& t7 jcell reprogramming from mouse to
& X$ v/ s2 j: E8 g/ `human using the same transcription
& T- A# j8 L% W5 @9 L& ufactor quartet further emphasizes the
1 V' F4 _; {0 A/ \& y0 kconserved nature of the Oct4/Sox2
: d1 q8 V# l. p/ N+ V ttranscription factor network that - D" r% p( G {, d# d, V, _
controls self-renewal of mouse and
7 z0 h b; f) A. u' thuman ES cells (Boyer et al., 2005). + v8 f4 q, U2 {0 T
Given that Klf4 and c-Myc are chro-
& S, x6 q0 `; z Zmatin modifers and can immortal-
4 g5 L+ Q; S |* H- l6 ~ize cells, one might be able to fnd 6 z s: O3 H5 {* O `& R/ k
other factors or small molecules that # _& n- T% B5 ]6 I6 Q; z0 b
could replace these two factors in the
9 b: a h, g5 q' N, g* O9 n1 l" ~. pcocktail (Yamanaka, 2007). In these
. Z) ?8 ]+ `: R" ?4 e. tstudies, the possibility of retroviral ' k- U. T$ u7 S' t+ _& p9 d, m3 q
insertional mutagenesis, resulting
6 F, B# d3 u1 H0 `& x$ ^$ Nin the activation of other genes con-
) s. B5 |" Q; S& }, ~tributing to reprogramming, cannot % t- b+ h5 B3 ?; R& z$ z
be excluded, providing an opportu-4 Z# e# [$ K: w( u) b/ ~
nity to potentially identify new repro-
2 {1 `/ B/ @2 o9 agramming factors beyond the cur-; i+ L3 e- j! c% b& c" C
rent quartet. Also, taking a broader 8 W# @* S$ T% T8 E1 t. y$ C
screening approach for reprogram-2 y/ c- v1 w. B' F6 Q
ming human fbroblasts (as Takahashi $ y, `2 d Y+ X9 S; A
and Yamanaka did for their mouse # i+ ?. U( y& f
study) might yield other combinations & V/ ]: [: Z! X& R
of reprogramming factors.
6 R5 O( g% h. _, k& }# E& @Direct reprogramming of somatic # e* ^0 {$ c. p/ ?
cells to a pluripotent state, thus revers-
& l7 }7 T i1 ?( A6 f& eing the developmental arrow of time,
- X8 z/ h; H: j+ c' N. |/ q9 gis considered by some to be the “holy
4 K- f0 Y7 S8 wgrail” of stem cell research. Once the % k+ \ S* J8 o. w9 Q
results in human cells are confrmed,
" f, X( E4 S) G' _8 f" ethese advances will enable the cre-0 \% E9 z+ `. d1 l
ation of patient-specifc stem cell lines
P3 Z) y' e2 V% p# Jto study different disease mechanisms
2 S6 e3 {0 @- T+ j' l* \' n2 sin the laboratory. Such cellular models 9 a9 K9 k2 z1 A0 p
also have the potential to dramatically . E+ m1 {5 q) G; Q3 L0 o0 X
increase the effciency of drug discov-
5 E) H' |% v/ n6 D. T: Z+ Qery and to provide valuable tools for 2 r0 f! T% }9 i1 S J: \/ f
toxicology testing. Furthermore, this
6 b/ j& F1 [3 ~$ k2 V+ dreprogramming system could make 1 B# X0 T# M+ ?8 D x9 V3 U# Z
the idea of customized patient-specifc
0 J9 y& g' v7 ]' |( hscreening and therapy both possible
% C- d/ E+ b/ `2 d( Xand economically feasible. Finally, the
9 `/ ?, Q5 S1 A, l8 g! iwork will have a powerful impact on 4 {+ Z& [4 C% H# D; Q- s
the intense debate regarding the moral,
k6 H# b8 }. v7 q& l! j! Treligious, and political aspects of ES cell ! r/ E& m$ ~! I7 C; i0 |0 v
research. However, a big mistake now
& n$ ^! m0 } {2 Xwould be to consider human ES cells " ?2 S7 a, g9 j) U: A6 `0 N
obsolete. There are still many hurdles
: p# |3 z+ _5 x5 qto overcome before we ful ly understand % D! w5 C6 y1 D2 c; Z
pluripotency and before we have human ! B2 c5 L1 t" I( ^! H+ |
iPS cells in hand that are suitable for . F6 `# u% {" k7 Z5 [" r, Y% Y
therapeutic application. For example,
( ]) P! D6 ^3 ~5 T" H% ca signifcant proportion of mice derived
9 w1 r9 Q( W# c$ D! z1 y, ^from mouse iPS cells develop tumors
( Q) {, e$ J4 B V6 Odue to reactivation of the c-Myc retro-4 n Z6 ~8 U; a/ ]/ p4 u
virus (Okita et al., 2007) compared to 0 |5 H8 X# j- w: P
mice derived from ES cells, which are 8 {; z1 o! v3 n% T
normal. The search is now on to fnd a , |: S* F; C5 m% ~% d
way to reprogram somatic cells without
$ G9 n; K* r1 [- B2 u% p0 lretroviruses and maybe even using a
9 S f9 ?& n! _+ k: e+ p, a+ W2 }; k# |cocktail of small molecules. Given this,
- {; W: g8 C9 ]( t0 q" xit should be emphasized that human
+ H6 W6 _& T; R; W( x0 L, y: A' UES cell research is more important than
" E( P d U# L, v( Lever for it will shed light on how iPS
& n' H( B5 O( T+ l- }, _. V( ]cells can best be maintained in their 9 N- T' N4 P! w
pluripotent state and how they can be
1 J- ~" H$ l! W: G7 Zinduced to differentiate into the cell 5 n5 C4 b6 \% b* ^
lineage of interest. The feld of nuclear ' T$ C' }7 H& e7 O: O: Y; o: T( O2 A- G$ K
reprogramming has come a long way
, a" S' Q% g4 afrom the initial nuclear transplantation : O# e% S5 \6 d" n
studies in frogs 50 years ago, to the
, x7 S) n1 x2 t$ j% E Fbirth of Dolly, the frst mammal cloned * z# w# f7 v7 M, f+ n5 l7 l
from adult somatic cells (Wilmut et al., 7 D3 E+ k2 e: \, Z1 g
1997), to the fallout from the fabricated
! q6 ]3 |6 D; Q; xhuman nuclear transfer experiments
. W' a$ B& w' l, xof several years ago, to the landmark
% S, y/ ^7 e! W1 b4 B7 qstudies of Takahashi, Yamanaka, and . U B/ p# } Z" N0 ]3 u; @
their colleagues, frst in mice and now ( Z) T" i6 _. Q8 z. t+ w( k
in humans.. p$ a. N: ~8 e. I9 G7 P! n
ReFeRences' |: K3 o1 B1 }, _
Boyer, L.A., Lee, T.I., Cole, M.F., Johnstone, : p ~* r: G3 z$ |' O
S.E., Levine, S.S., Zucker, J.P., Guenther, 6 t9 K5 A" ~* W8 F9 F" h) i. |
M.G., Kumar, R.M., Murray, H.L., Jenner, R.G.,
9 ^4 P* ~( L' u5 \8 _2 x; r( Fet al. (2005). Cell 122, 947–956." z S5 _" P) S; ?& {0 Z
Evans, M.J., and Kaufman, M.H. (1981). Na-' I2 ]) `$ U4 @: J
ture 292, 154–156.' g& F6 ~: o, d$ P/ p4 _0 N D& j
Maherali, N., Sridharan, R., Xie, W., Utikal, J.,
' U0 O6 @! U; _/ nEminli, S., Arnold, K., Stadtfeld, M., Yachenko,
8 [# P7 [& {- w2 l4 D0 _R., Tchieu, J., Jaenisch, R., et al. (2007). Cell & v. D/ ^" y( M" ~2 _
Stem Cell 1, 55–70.
# e- H6 o$ K0 [- ~- O; ~0 _6 |1 ?Martin, G.R. (1981). Proc. Natl. Acad. Sci. USA / j, ?1 T# J$ V% W1 @
78, 7634–7638.# F* \, C' B. a5 S3 x6 U( v' L2 x
Okita, K., Ichisaka, T., and Yamanaka, S. ' w3 C K1 u$ e5 f1 k. Y. u& |7 f. Z
(2007). Nature 448, 313–317.
) }0 \. Y8 Y* q3 h* t# R, e5 ATakahashi, K., and Yamanaka, S. (2006). Cell
! c5 n3 D; F, y5 j* j! H4 v' I5 m126, 663–676.
& Q1 Y# S1 K* ?' R0 G/ u: BTakahashi, K., Tanabe, K., Ohnuki, M., Narita, 9 Y8 y8 g, ], Z' { }! i. s' x
M., Ichisaka, T., Tomoda, K., and Yamanaka, S. e: `* ` Z' x& N( `# C, f
(2007). Cell, this issue.4 r8 C- L- o7 X/ j. r. q
Thomson, J.A., Itskovitz-Eldor, J., Shapiro,
$ s7 ~5 X( q. f" n# _+ r. TS.S., Waknitz, M.A., Swiergiel, J.J., Marshall, 6 N9 F- X- {3 z" n/ w' e
V.S., and Jones, J.M. (1998). Science 282, 0 g( V8 ~8 v" Z- K
1145–1147.6 A/ n4 N% \' C4 ~+ f, c
Wernig, M., Meissner, A., Foreman, R., Bram-8 D" I" o8 L" c8 e% c
brink, T., Ku, M., Hochedlinger, K., Bernstein, & q( f c5 {3 [5 T! Z. T
B.E., and Jaenisch, R. (2007). Nature 448, 7 ?2 ~* o/ ]: S4 I; ]& \% z
318–324.1 k, ~. L* F9 Z& E- ~0 m7 i
Wilmut, I., Schnieke, A.E., McWhir, J., Kind,
( {% U% I* e/ l+ N9 f& X1 [A.J., and Campbell, K.H. (1997). Nature 385, }( C3 c0 H' `! V! W. L, {
810–813.0 E- I# Y2 t' o8 F" }; P5 r7 p
Yamanaka, 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
