|
- 积分
- 0
- 威望
- 0
- 包包
- 4
|
Induction of Pluripotency: 5 O& q! _: K( G
From Mouse to Human
5 G n# l$ c8 J. l. A W# sHolm Zaehres1% k7 U# p& D) _1 w, [! ?* P3 `
and Hans R. Schöler1,5 u i0 D1 ]* }' ]! ~9 c
*
3 d f" Q6 b0 a8 d* \0 V1 Y/ S4 }) L( C6 R2 z: R
Max Planck Institute for Molecular Biomedicine, Department of Cell and Developmental Biology, Münster, NRW 48149, Germany
/ `: N9 c: J0 Z/ D8 Z: t" t*Correspondence: schoeler@mpi-muenster.mpg.de% w4 B/ @: M! d5 L, F
DOI 10.1016/j.cell.2007.11.020
& Z0 ^! D. e3 o$ \: D5 p# TIn this issue of Cell, Takahashi et al. (2007) transfer their seminal work on somatic cell & T7 L6 O" q* u, \
reprogramming from the mouse to human. By overexpressing the transcription factor : M1 _" ]: U7 n% v1 C
quartet of Oct4, Sox2, Klf4, and c-Myc in adult human fbroblasts, they successfully
/ h# s+ ^0 g, @: z3 Risolate human pluripotent stem cells that resemble human embryonic stem cells by all - g7 O" H- h; v; R3 }8 j8 w. n
measured criteria. This is a signifcant turning point in nuclear reprogramming research * e& u, P8 m% F3 ? S8 u/ C; w
with broad implications for generating patient-specifc pluripotent stem cells for research
g6 j4 y/ g0 w) ]9 {7 ~and therapeutic applications.* F( O/ Y) s- e6 Q$ ^
This year’s three Physiology or Medi-- e, b0 S& ^5 m: |! u
cine Nobel Laureates—Martin Evans,
% i, l$ J( L0 k* d1 aMario Capecchi, and Oliver Smithies—
0 {- ^0 _4 M6 w; y7 p: G: f# g9 y, ewill be honored in Stockholm in 10 7 w& L+ J8 V+ \8 V: t, t
days time for their discovery of DNA
3 ^$ b4 C6 I( d, irecombination and the development ' \6 @0 M" h- G4 D" u8 k# A6 H1 E
of mouse embryonic stem (ES) cell
1 d3 [' [ t, ?technology. It was Martin Evans who ! n3 f% Z* ?! ?5 ]; q
discovered how to make mouse ES
F' }+ F/ v, e3 mcells, enabling any genetic alteration
/ e5 z5 t8 D h6 B6 d Rto be transferred to the germline and 9 P8 a1 u% @! u- j) O) V
hence to the next generation (Evans
$ A! k# | k! n& p8 w* P: o/ t+ ?and Kaufman, 1981; Martin, 1981). ' u& I& Y* s( C; R) n
Before this breakthrough, researchers , a! o% X# b/ I$ O( w& G* Y
studied mouse embryonal carcinoma
+ O+ _$ m8 j! \# H/ bcells derived from tumors, which
# O7 N; H, O5 n1 a- \, q% B/ Zcould form every mouse cell lineage
# O9 q' T' y- I7 \ P- kexcept the germline. Combining DNA ' `: Y' P: Y% b$ P! E7 [
recombination and mouse ES cell & c# f* D1 V! q1 @5 ]
technology revolutionized an entire B# T" u' ^' l. j0 {; D
feld of research, forming the basis for 1 p" V h2 T) {3 L4 c* X
studying and understanding the roles
# ]$ W. ~5 t) p: Jof numerous genes in embryonic 4 H+ i; z9 v9 D( j6 ~) C
development, adult physiology, dis-1 h' G0 S* t2 w/ m$ G0 e) N
ease, and aging. To date, more than 8 W# @" @ q0 q, _5 w8 x- r( G6 u3 d4 j
500 mouse models of human disor-; {* I7 R; }: R! e, m! k
ders have been generated. Now, with
0 z6 z7 _! W. {: b% ^the study by Takahashi et al. (2007) / C9 b% g* ^% T3 i1 z5 o
published in this issue of Cell, another
* b4 `# k( T& _' iimportant revolution is taking place.* T0 `6 b) G% A! v1 y
Last summer, Takahashi and : v. W& T$ V; w, T" R: B
Yamanaka (2006) stunned the scientifc
# a7 K1 i/ ], i4 @, D7 lcommunity with their study showing
5 _4 R: f6 l5 O' @. t; ^9 r8 @molecular reprogramming of mouse
5 U e4 f/ s. vsomatic cells into induced pluripotent 4 Q5 B& i! m& `7 {& p
stem (iPS) cells using just four factors: + v3 O' p1 X4 v% k' }
Oct4, Sox2, Klf4, and c-Myc. Their
0 h8 ?8 n, \* D9 q* l4 qelegant but demanding approach of ; T4 i+ S" M& E3 l) t
screening for a cocktail of factors that # n# g/ d, N9 U) P3 K
could reprogram mouse fbroblasts
9 W& t6 L: t/ s0 k; u7 U: sstarting from 24 candidate genes paid
: s5 ~7 l( R t& [, o( ?off with their detailed description of iPS 4 R3 x5 F5 v' b& h
cells, which are almost indistinguish-
1 l# Y4 b$ P- j! cable from mouse ES cells. As with all
/ }2 `# q- T4 y. f* {- L* {( F# uscientifc discoveries, these exciting
( v6 ]7 R# @; d' jfndings had to be reproduced. Sev-
& n7 w& {7 ^0 peral studies published this year not 4 e8 P5 B+ n, G$ F; E
only reproduced but also extended 1 t" g6 X4 F$ J
the Takahashi and Yamanaka fndings
1 _0 I) S3 W4 i! b" Uby demonstrating the pluripotency and
$ E" p# S) M: r \ Idifferentiation potential of mouse iPS % E4 G/ q* [% ^+ x4 C4 u
cells in rigorous developmental assays
! d: I2 |, f+ J" U: {1 J$ l6 G: k(Maherali et al., 2007; Okita et al., 2007;
% D4 Y5 z# P/ _+ p! h- h3 q% \+ u6 Z$ oWernig et al., 2007).
: |9 [( @7 S5 I4 t; uIn their new study, Takahashi, ' L {% s# S/ T; z0 L( e5 [! o
Yamanaka, and their colleagues
' G H& q/ y' ~+ V/ z* H. |8 K) u* j* I(Takahashi et al., 2007) now translate / Z: a9 Y/ q" @1 P
their remarkable fndings from mouse
* p, b; z) r, z5 R) ^to human (see Figure 1). They selected 3 g1 u/ d9 s& z# C
adult human dermal fbroblasts and
% \. ^( e+ t& F; Z$ etwo other human fbroblast popula-; `! S* P+ O2 i4 l. h
tions (from synovial tissue and neo-
# a8 q% [4 g" D9 ]2 l+ \* v2 inatal foreskin) from different human
: A' [0 l& b+ P( W2 j& P: Adonors as their reprogramming target
- H* k1 e. @0 c* [& Icell populations. They then trans-
5 o- I% Z7 l' N5 D/ f1 G a2 Vduced the human fbroblast cultures
& W1 Q" M0 D/ d- Vwith retroviral vectors carrying trans-
9 s- Z ^6 T0 Y% D4 a0 Mgenes for the human versions of Oct4, ! {' [, S+ _& G4 O4 L
Sox2, Klf4, and c-Myc and cultured
% Y- z) t% [& G4 l' Othe cells under human ES cell culture $ q! p$ [/ x1 I3 c* ?( F5 Q R
conditions. Thirty days after transduc-
1 B$ a, m9 U, K8 `1 E! ]( ftion, the culture plates were covered * |( f7 g+ ?- z+ ?" O2 P
with human ES cell-like iPS colonies
, `0 f- ^& E% Q) z6 a' `(among other colonies), which could ) w2 F$ T @- o4 @
be further propagated and expanded. 4 l& c, J/ g$ Q+ I/ L7 [6 {4 K
The retroviral vectors enabled silenc-
* }8 B: z& ]) I) w6 Ping of all four transgenes after human # Q2 W6 A/ z9 M p1 g) G; ~
iPS formation (as found in the mouse
. R0 _' O. O( `2 I5 J# g" Asystem) indicating that the iPS cells ; M, S; ~+ y3 f
are fully reprogrammed and no longer
% O; V, d7 Q% R; Q2 B, mdepend on transgene expression.( F6 u( V' R- |0 Z
Unlike the mouse study, human
/ Y9 |: Z) G, S7 u+ k6 }# GiPS cells were generated without any
% i0 [/ I+ C3 ?5 I0 }genetic selection procedures. Given
W; j4 u' c! X* j6 [the lower mitotic index of human ES % K* \5 C8 C6 Z1 W* G" y# G' ?
cells, it is not surprising that the gen-
0 j! D' h1 m4 o! P" l Veration of human iPS cells takes nota-% b% p. l! f+ L$ q, Y
bly longer than in the mouse system. 8 Q1 o$ g$ Y& u1 X$ ^3 s& [
The authors subjected their human 4 p' R1 ~! r7 O% a/ }! J( J1 y
iPS cells to a panel of assays to com-
0 b" I. ]. K$ R1 n3 O' n6 ^( Vpare them with human ES cells. These
6 b, h2 c4 N2 u* O& _- vassays included morphological stud-
8 b. |& L% w, x. h5 @" u8 u* g Dies, surface-marker expression, epi-
" y* D# @) d; |, g. _6 _genetic status, formation of embryoid
. p% O$ o5 y) h0 l1 h9 V6 j2 qbodies in vitro, directed differentia-/ t( ~1 Y/ v2 ^' |
tion into neural cells and beating car-$ i/ _% W1 c2 [
diomyocytes (according to human
" a* e; E9 Y3 p/ H% ^ES cell differentiation protocols), and
q4 [" J9 J; X) H; p$ Efnally teratoma formation in vivo.
% N# ^% w+ I9 VDNA microarray analysis revealed
$ W; b- H( `, t9 b7 _# Q8 Zthe remarkable degree of similar-6 R2 `" [& z$ k
ity between the global gene expres-
- S2 K+ v9 `: p% j# \sion patterns of human iPS cells and
7 d* ~ J. j* u; hhuman ES cells. Notably, genomic
5 D9 {7 p/ Y( i% GDNA analysis as well as analysis of
" J# u# G' H9 ^. w: h0 `short tandem repeats demonstrated
$ R0 U- k/ R# g( dthe genetic origin of independent " c3 G2 A# E8 ]) ]- ~, g% ^2 |# _- M
human iPS clones from their parental ; N! G8 t9 n$ C# B
fbroblast populations.0 P6 v' f5 Z& Q
The derivation of mouse and then ?9 @6 [9 ?; D$ E* }6 u
human ES cells (Thomson et al., 1998) 4 h8 s3 f8 T- c( S
as the gold standard of pluripotent
' V c4 _1 \3 t) @stem cell populations has necessarily ; i+ x: N( E: r; `0 I
led to emphasis on differences in the
, @1 K6 K. J7 Eregulation of self-renewal between
" S! E1 X# f- o$ J4 d% k6 X! Amouse and human ES cells. For " d6 i& a3 q" Y: [' @* U
example, human ES cells depend on
3 v- u0 m$ p+ p3 B) e$ U3 ?bFGF for self-renewal, whereas their 7 ~0 w6 o L7 A
mouse counterparts depend on the 1 h: k& Z$ ]9 i, c
Lif/Stat3 pathway; BMP is involved in ! u' I9 J) C' M. o% |
mouse ES cell self-renewal, whereas
4 c; Y7 x" s: q+ R5 ]* win human ES cells it induces differen-7 X. Q- U% m6 c# I6 q7 l# @$ E( S0 R
tiation. Extrinsic factors and signals 9 D& a, r* I, I( `
for maintaining pluripotency may dif-3 ]" q. G% n- A5 l% t( I8 w* `/ R9 I
fer between mouse and human. How-+ r+ U' q6 u% m) r; q
ever, the ability to translate somatic 7 I) Y) N" G3 r- d4 D
cell reprogramming from mouse to
' D0 M M d: _6 `3 Bhuman using the same transcription ! u4 }+ O7 M! l! g% ^) P
factor quartet further emphasizes the
2 }4 _% d' m9 y {0 d. Q, j. @conserved nature of the Oct4/Sox2 2 T' I" S/ R l. N
transcription factor network that 1 g1 Z0 I- r7 f# D
controls self-renewal of mouse and
4 Q+ h4 ?9 Y$ o2 bhuman ES cells (Boyer et al., 2005). , X# _& ~' N- v' N3 U2 b
Given that Klf4 and c-Myc are chro-
- C" T( _, V8 g4 c7 T- a0 Ematin modifers and can immortal-( M1 D5 N, B, V2 r
ize cells, one might be able to fnd
* p% }9 P. n# c& l' v# y' @6 Mother factors or small molecules that 5 V6 Q" k m; u$ k: s) Q
could replace these two factors in the
! V0 ]7 i6 o9 k/ {. pcocktail (Yamanaka, 2007). In these
. |" C+ p$ Z; h7 m' istudies, the possibility of retroviral
! G% L7 _' b3 }( dinsertional mutagenesis, resulting & u9 O* x$ K" D
in the activation of other genes con-
6 W$ ~3 {' S( Ttributing to reprogramming, cannot
/ A. A4 p9 B8 } d& `be excluded, providing an opportu-1 y, x9 X( w" F+ b8 @8 t9 \) e
nity to potentially identify new repro-
- i9 d5 y4 t- Bgramming factors beyond the cur-5 _# K( f% ~5 v/ D
rent quartet. Also, taking a broader ) J2 U) X- N+ U' @6 _
screening approach for reprogram-
7 U; Z5 X! S* s# b# c' p# m t7 Eming human fbroblasts (as Takahashi
$ v4 x& A' z+ M; band Yamanaka did for their mouse
+ g* M1 [6 ?: ystudy) might yield other combinations
' |4 @5 j8 x$ Y# S Y- lof reprogramming factors.1 _. u% J7 g4 r
Direct reprogramming of somatic
% Z% }! C. z/ L. Gcells to a pluripotent state, thus revers-1 w; u" C7 h0 n
ing the developmental arrow of time,
- g) ]+ m. E& U" q2 @is considered by some to be the “holy
6 K6 X0 N& ^5 d3 n$ `grail” of stem cell research. Once the * R" m0 k% ?6 ]; p5 R$ ?/ X
results in human cells are confrmed, , `, S4 M! W+ i6 ?, s9 n
these advances will enable the cre-
* p! [" p( V" qation of patient-specifc stem cell lines
! C' X# S4 ]4 u) i) uto study different disease mechanisms }6 E$ v& g) P9 q0 A
in the laboratory. Such cellular models
4 Y2 X# G! |+ E5 Falso have the potential to dramatically
, M2 k( @% N2 H, y mincrease the effciency of drug discov-
' s9 J u4 U8 s7 f4 u# w( Jery and to provide valuable tools for * Z( b. n! z" B: P" F
toxicology testing. Furthermore, this + I- s. b( H Z( s" K. L* D
reprogramming system could make
{9 a5 S+ _- _/ l J1 v2 qthe idea of customized patient-specifc 3 h$ D' ?6 P2 x( E x
screening and therapy both possible 5 E8 C9 m) g& D
and economically feasible. Finally, the * S' ^& Q' z9 }# p. `! o$ ^0 s7 A
work will have a powerful impact on
- g. I: _! ~! e/ ~: F/ W+ F% ^the intense debate regarding the moral, : `0 T) Z" M* E! C0 I4 z0 u0 D
religious, and political aspects of ES cell , B/ |5 @3 @- E9 A4 G5 x0 `- V
research. However, a big mistake now
; u) G( W( O J' R- ~3 J- rwould be to consider human ES cells ) [7 ]( z/ V- \! K6 j" q( D3 C. @ M
obsolete. There are still many hurdles " d% R% T( b, }% P
to overcome before we ful ly understand
& Q$ l2 @8 D& b% h& i1 [' kpluripotency and before we have human 2 J9 [5 }+ P1 L7 y9 w/ |
iPS cells in hand that are suitable for
7 o9 O2 {" d5 K0 w( r% [9 Htherapeutic application. For example,
4 g8 P2 s f7 qa signifcant proportion of mice derived
. g* b6 N/ b" n' H, a& mfrom mouse iPS cells develop tumors ; Z* U0 w2 Y7 Q+ u. p" J: [
due to reactivation of the c-Myc retro-. W& M7 Z7 t# p2 t8 Q
virus (Okita et al., 2007) compared to 4 T0 c. Z1 X2 o5 x, D: ~* r
mice derived from ES cells, which are * i- J+ l/ `+ \
normal. The search is now on to fnd a
: n5 m! I9 P; Q6 M8 t; Iway to reprogram somatic cells without
* d1 a7 c; C: f. Z( p; F0 B2 ]retroviruses and maybe even using a & f3 _3 @0 \0 u, ]! }: Y# E; j
cocktail of small molecules. Given this, / u" }* S) n z. f! B/ c
it should be emphasized that human
/ o( J1 }5 T' h7 Z" b- `' _; ^ES cell research is more important than 2 x& ]1 a8 |/ K
ever for it will shed light on how iPS
?- z' ?6 }1 Z' ccells can best be maintained in their ! j- o! \! j. K% D
pluripotent state and how they can be
2 y0 r/ @; ` {" O0 }5 Kinduced to differentiate into the cell
# A! i2 ]/ w" i7 h7 {. ]4 o* Qlineage of interest. The feld of nuclear
a* w `9 ^) s+ P# C2 \& ]' K% Breprogramming has come a long way 3 c9 Y, U5 T' J5 G z, k3 N
from the initial nuclear transplantation 8 q4 T& B$ L! s* Y4 a* L, t1 L
studies in frogs 50 years ago, to the * ^' p% }$ ^. D( I- x1 C4 C' u7 o
birth of Dolly, the frst mammal cloned
3 V% d/ ?* k" Q+ g* w6 mfrom adult somatic cells (Wilmut et al.,
$ X. ]. W' p. p1997), to the fallout from the fabricated ' M5 n% ?6 f, R, o8 T
human nuclear transfer experiments ; m) u* P f* \1 h: J% Y3 x1 _& k- B
of several years ago, to the landmark
% d$ X' P3 ?9 M" z x! l; fstudies of Takahashi, Yamanaka, and
. l- M3 F% M" j5 d7 C: Q% H& Z* j6 t5 Vtheir colleagues, frst in mice and now ! k2 x* U' b/ g% U$ o; O/ m4 v
in humans.
2 M( R* p) Z1 [9 X$ OReFeRences
3 E* h. d0 u! U" e6 m2 r3 EBoyer, L.A., Lee, T.I., Cole, M.F., Johnstone, 0 d; ? @+ N4 ]
S.E., Levine, S.S., Zucker, J.P., Guenther,
: U* e4 L0 R3 T( W+ Q! hM.G., Kumar, R.M., Murray, H.L., Jenner, R.G., 9 Y; |5 }0 O4 ^, W! q
et al. (2005). Cell 122, 947–956.2 V) ^/ r/ D& d! R% o: |
Evans, M.J., and Kaufman, M.H. (1981). Na-
7 @* @ @- e/ P) i- {2 E% pture 292, 154–156.1 ]! r, C |% k h
Maherali, N., Sridharan, R., Xie, W., Utikal, J., 4 f1 \$ @ @* b# `. l! v4 Z- f& x
Eminli, S., Arnold, K., Stadtfeld, M., Yachenko, 4 c& [5 O5 C& q+ \( y
R., Tchieu, J., Jaenisch, R., et al. (2007). Cell + q6 D# K* V; O" G1 \, N' Z. D h
Stem Cell 1, 55–70.# v" z$ K0 f( j/ C& I% E7 w0 G
Martin, G.R. (1981). Proc. Natl. Acad. Sci. USA
: h+ U3 p+ H9 D1 {/ w$ J i78, 7634–7638.
. F2 L* n2 D1 T/ ]9 wOkita, K., Ichisaka, T., and Yamanaka, S. 9 }, o* _! S6 M, X
(2007). Nature 448, 313–317.
* I4 ?+ {9 Z6 g% z: lTakahashi, K., and Yamanaka, S. (2006). Cell " W1 t, A% c5 k' F1 Z2 k# ?
126, 663–676.
& O7 t' O5 t1 s8 P G6 C2 ~, qTakahashi, K., Tanabe, K., Ohnuki, M., Narita, : j( x' [# E4 Z5 |9 C! {
M., Ichisaka, T., Tomoda, K., and Yamanaka, S.
6 n: e9 D' n9 n: X(2007). Cell, this issue.
2 k) ~+ v+ L3 x) hThomson, J.A., Itskovitz-Eldor, J., Shapiro, 0 ~6 t$ z8 z! e! ? ~1 o
S.S., Waknitz, M.A., Swiergiel, J.J., Marshall, % s1 u) R. `$ R+ A" c
V.S., and Jones, J.M. (1998). Science 282, " X) s$ w9 p+ N
1145–1147.
' J# r4 k% T7 v" y7 AWernig, M., Meissner, A., Foreman, R., Bram-
% r- v% A5 Y e& T9 [brink, T., Ku, M., Hochedlinger, K., Bernstein, J" v0 ?9 s( o+ i+ Y* i# x
B.E., and Jaenisch, R. (2007). Nature 448, 7 D: q* `7 s' e e4 ?# \7 S: q/ X2 H
318–324.2 ^$ D+ {/ q n3 @$ U
Wilmut, I., Schnieke, A.E., McWhir, J., Kind,
: \1 ^5 v" e4 [8 O1 b) B* S; fA.J., and Campbell, K.H. (1997). Nature 385, 9 c# p7 e' _) n
810–813.
( T" Z) R$ U7 SYamanaka, S. (2007). Cell Stem Cell 1, 39–49. |
|
发表于 2009-4-28 21:35
发表于 2009-5-16 10:41
