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Induction of Pluripotency: ( \# O5 j8 N& t4 W7 o# y7 B4 \
From Mouse to Human
! m. b3 W9 ^1 DHolm Zaehres16 ^. Z! q3 F" d6 v
and Hans R. Schöler1,& \# B9 D0 O3 X V
*, Q( ~. w. A" n
1 l. L' g) N7 N
Max Planck Institute for Molecular Biomedicine, Department of Cell and Developmental Biology, Münster, NRW 48149, Germany
, X% ?6 e0 N' A. Z' i*Correspondence: schoeler@mpi-muenster.mpg.de1 D5 V# {2 L Q4 V) B) T! n4 X* Y
DOI 10.1016/j.cell.2007.11.020
% Q! E+ o8 Q- }In this issue of Cell, Takahashi et al. (2007) transfer their seminal work on somatic cell
; E; D' V: g4 J2 I( areprogramming from the mouse to human. By overexpressing the transcription factor
) y2 C% s I' d1 B6 B6 Zquartet of Oct4, Sox2, Klf4, and c-Myc in adult human fbroblasts, they successfully 1 Z* e1 p& p$ p+ U0 v# v
isolate human pluripotent stem cells that resemble human embryonic stem cells by all ! E4 ?: x0 h9 G7 v# `* r2 N; h
measured criteria. This is a signifcant turning point in nuclear reprogramming research
. G% f- a. T! k/ ]; o' R+ ewith broad implications for generating patient-specifc pluripotent stem cells for research 3 ^, k: B, r9 V$ y2 Y' M, C
and therapeutic applications.
# p! P, _2 Q" q0 d E' CThis year’s three Physiology or Medi-/ Q/ ^/ y' o0 O r1 J( o6 ?
cine Nobel Laureates—Martin Evans,
- Y4 Z; i; v# J9 i8 d" XMario Capecchi, and Oliver Smithies—
! B, G j$ b6 L7 f# I% p q; J+ |5 n: u7 fwill be honored in Stockholm in 10
+ g1 J1 K' B/ s8 ~days time for their discovery of DNA
% L; F# L5 w8 Y3 `$ [recombination and the development
' E4 |3 M/ o0 e% @of mouse embryonic stem (ES) cell
. \/ F3 e: c: l/ v4 E) H$ jtechnology. It was Martin Evans who X6 |" X$ Q7 J K Y
discovered how to make mouse ES
" K* o* m/ j* `' mcells, enabling any genetic alteration 7 ]) S' r6 r5 N N0 @4 x4 f
to be transferred to the germline and - H' C5 R/ i7 y; D5 s% ~. t
hence to the next generation (Evans
9 {" t8 n! r8 s- @5 w% ^and Kaufman, 1981; Martin, 1981).
. u+ t. _2 ]' u+ P* M2 o" {Before this breakthrough, researchers 6 P0 E3 e# J* C1 ]. {
studied mouse embryonal carcinoma
0 w) { ^9 c$ f% t# o Y M9 Y( ?# ycells derived from tumors, which ) q% N9 R* h% z! _' ?$ N3 q) [7 X
could form every mouse cell lineage
. V+ K4 E$ x! ?2 Nexcept the germline. Combining DNA 9 c' x8 @2 v5 D: B) A( w9 _
recombination and mouse ES cell 4 Y2 |" K9 I* t% e; U4 }7 g. a. ?
technology revolutionized an entire ; o. U; H, f6 |8 P
feld of research, forming the basis for : o7 `" i( C, U# {/ T4 _
studying and understanding the roles
% e+ V3 C+ Q& U9 {3 S* |of numerous genes in embryonic
8 r: K9 w8 u2 _8 V& i% H l; Zdevelopment, adult physiology, dis-( E: ~- p: Z6 N: i$ p
ease, and aging. To date, more than % S8 O2 X' w/ u/ P% C1 w+ t1 w
500 mouse models of human disor-
6 g5 ~' P2 m7 D1 M& i+ sders have been generated. Now, with
. ~/ H3 `9 m/ e: k8 u8 d) Hthe study by Takahashi et al. (2007)
+ g& ~/ R/ C# q! w' t" mpublished in this issue of Cell, another : J1 T# q5 M+ c6 k5 K( h; h
important revolution is taking place.
' Q" m/ @" O& mLast summer, Takahashi and
! |( ^% z, M: G$ h! ?Yamanaka (2006) stunned the scientifc 8 e$ E, b9 s; L- y+ H3 C
community with their study showing
4 n C# ?. I, |% E5 J4 M( Zmolecular reprogramming of mouse 5 M# r# p. |- W# u
somatic cells into induced pluripotent 2 H: ?7 Q p8 ^, r& ^
stem (iPS) cells using just four factors: 5 c3 s1 E" E# N! _
Oct4, Sox2, Klf4, and c-Myc. Their 5 M, x5 n2 ]. ]* A
elegant but demanding approach of ) [: q- g* ?: Y1 X: O+ s* U3 }
screening for a cocktail of factors that " u5 \, p$ P- u2 S3 a% D9 E
could reprogram mouse fbroblasts / _- `- C8 [& o+ P
starting from 24 candidate genes paid
" K [$ ^7 D* Q3 {off with their detailed description of iPS
. N* Z7 q( D. v2 p" w/ @8 _cells, which are almost indistinguish-
$ L$ @. N0 t, @1 A( [, [7 Hable from mouse ES cells. As with all $ P; _! |1 A) ]$ E
scientifc discoveries, these exciting ( r8 ]: w: s, h2 ~/ p" e# G
fndings had to be reproduced. Sev-
/ |$ u2 f( v( T& g4 D* I- [eral studies published this year not ; u# w8 K& f+ f2 m% S# s* a
only reproduced but also extended
" ^8 X7 q. C. \8 `* Jthe Takahashi and Yamanaka fndings , O2 w) p: X) T8 Q0 X% a1 [- z8 q& ]7 g
by demonstrating the pluripotency and 8 A9 B, b( y) t, |6 `
differentiation potential of mouse iPS ' L% W2 ^4 ?. d) e
cells in rigorous developmental assays ' j' v/ Q/ G( z
(Maherali et al., 2007; Okita et al., 2007;
4 G; D4 b1 t6 @Wernig et al., 2007).; c5 h$ ^+ T. m' e) z, D
In their new study, Takahashi, : Y- f. X( b% Z- {, y' U: L
Yamanaka, and their colleagues
! Y' S( Z: |( j6 n2 I(Takahashi et al., 2007) now translate 5 q- a. k6 @ I0 {4 n5 X+ E! R
their remarkable fndings from mouse ) z% M. Q5 j1 P7 U
to human (see Figure 1). They selected
6 J# d- i% O1 r0 x( a r' v% kadult human dermal fbroblasts and
7 Z0 P. k+ k/ Stwo other human fbroblast popula-% ?3 }$ G% o8 _8 b; g
tions (from synovial tissue and neo-+ R1 V- T$ H$ ?- r- o
natal foreskin) from different human
0 d$ @0 \; ~" e! N ]: ]donors as their reprogramming target
5 |$ s6 f! p9 j! @7 [cell populations. They then trans-
, r- Z$ |0 ^2 s! k: Mduced the human fbroblast cultures 4 I8 T' D$ ]+ |$ m
with retroviral vectors carrying trans-* Z( v( l. J' h4 J( E/ ^
genes for the human versions of Oct4,
6 @# G# ~, h* O! ~! nSox2, Klf4, and c-Myc and cultured
" m. |- h4 u: q& _4 o Qthe cells under human ES cell culture 4 L' Y% [8 m& X8 c; X9 ?& B
conditions. Thirty days after transduc-
z# q$ m! p7 ftion, the culture plates were covered ! o: r- I6 I+ y" B. I5 c. C
with human ES cell-like iPS colonies
) W! l5 w, `7 J- G0 O(among other colonies), which could
6 d- }, S5 x( V$ ~be further propagated and expanded. 1 A' u5 b" R3 j8 H9 ]
The retroviral vectors enabled silenc-
& @6 {/ Z( L8 d/ p- H( k6 Ring of all four transgenes after human
( e* q2 o4 v/ f+ w9 A+ `0 ^" BiPS formation (as found in the mouse
6 Y/ ]8 N9 R7 O1 q$ u1 ~1 ^! vsystem) indicating that the iPS cells 2 P$ l3 Z4 {. T$ H
are fully reprogrammed and no longer
* @+ g! r# ^1 v$ t) R. adepend on transgene expression.8 Z. w$ k0 K6 y* @: u! b
Unlike the mouse study, human
$ R+ N- b1 B6 b8 J$ siPS cells were generated without any ' P4 E/ \0 u6 _
genetic selection procedures. Given $ T6 E J( ?$ @- ]+ ~- F
the lower mitotic index of human ES 4 e( q$ M0 w) D8 ~6 s4 T
cells, it is not surprising that the gen-# D0 y- f) Y0 {2 d# p/ d! |
eration of human iPS cells takes nota-+ @# B; _, N" J* b" f+ z. J
bly longer than in the mouse system. i0 M- E- R" ^9 t/ I
The authors subjected their human # T4 E: n' E$ Z' Q. _( X' E
iPS cells to a panel of assays to com-
- h- c; f5 |) I% Rpare them with human ES cells. These ) a. [7 v3 J* h' `' j: p/ i
assays included morphological stud-
9 [% _; W6 }0 J7 O+ Y* dies, surface-marker expression, epi-
$ n/ R. [2 M; k, e8 ogenetic status, formation of embryoid
2 j- Z ?. E% }; x6 g& h, Zbodies in vitro, directed differentia-5 v3 Y0 ?4 c% m
tion into neural cells and beating car-
7 Z1 [7 _) B ]2 F3 qdiomyocytes (according to human
, D; u6 M X1 ?+ h$ d' cES cell differentiation protocols), and
: U4 ], b- {$ S4 m3 R3 `+ a. Y9 ffnally teratoma formation in vivo. , \, B5 K9 J9 J, h
DNA microarray analysis revealed ; v3 d* [: \8 s, }
the remarkable degree of similar-' x- f5 K/ S$ g3 ?+ |
ity between the global gene expres-
6 h5 i1 F! o m1 H( usion patterns of human iPS cells and
) |. Y a! |" z3 p. Ehuman ES cells. Notably, genomic - O+ M( ?0 F& h$ B& n) q, l, o
DNA analysis as well as analysis of 5 H0 \2 k S$ u0 q/ h2 x/ @
short tandem repeats demonstrated
( r/ P4 I3 S' a+ A- w' \the genetic origin of independent # E$ A% @* \# e# g2 J7 ?9 q
human iPS clones from their parental ( I" y4 {; v/ E# ]5 C
fbroblast populations.) Q( s# n' o$ H& |. Y) O3 s
The derivation of mouse and then
8 R9 }& k$ s; u$ q; R' qhuman ES cells (Thomson et al., 1998) ) r" W- Q5 Q2 Y' C. K3 _. A
as the gold standard of pluripotent 6 m1 _! M7 @: K4 T
stem cell populations has necessarily
& [" O+ E- g9 I1 mled to emphasis on differences in the
+ b+ A* z5 V V2 |. u/ Rregulation of self-renewal between
: c4 y2 j# ^- A; [mouse and human ES cells. For % o* C9 L7 O7 _5 J: U( C
example, human ES cells depend on
; Q! a7 n h4 ]$ F1 @1 S8 ]1 NbFGF for self-renewal, whereas their # {3 W6 i" I. [6 G8 J1 M
mouse counterparts depend on the
5 m4 X0 F, Z3 [" z* T, L# ]Lif/Stat3 pathway; BMP is involved in
( q. \" L2 \1 Y t2 @6 u+ X' h4 I" kmouse ES cell self-renewal, whereas 6 [8 s& K2 j& w& q5 y3 @
in human ES cells it induces differen-$ @$ }0 e8 u) h9 u. @/ v; `
tiation. Extrinsic factors and signals . w; c' M/ s8 D
for maintaining pluripotency may dif-
/ l# X" S7 i: \5 A6 @fer between mouse and human. How-$ _% p$ X8 ?. E0 i8 r
ever, the ability to translate somatic
; ]$ `7 ?; [7 U9 k Icell reprogramming from mouse to 4 N7 _" [ ?2 Z; Y6 V; C
human using the same transcription
: y4 y7 P, F8 ^& Hfactor quartet further emphasizes the : t( B+ [$ l7 T
conserved nature of the Oct4/Sox2
/ w& `0 F. j. S/ a- Ftranscription factor network that
5 t2 `& R- e4 k( l; s$ S4 mcontrols self-renewal of mouse and
) B& _$ v. d+ g9 Y3 i q$ {human ES cells (Boyer et al., 2005). % s/ d8 k- A- @+ a7 l
Given that Klf4 and c-Myc are chro-8 R$ ?* n. r6 V+ {
matin modifers and can immortal-9 }% N7 n3 p% N4 g4 D0 g- Z `
ize cells, one might be able to fnd J* a I7 u6 T; f; f
other factors or small molecules that
9 i2 y0 b, z7 n& R+ X, scould replace these two factors in the : ^6 v$ ]0 _" M- |8 y+ U9 h
cocktail (Yamanaka, 2007). In these
/ s4 {0 @4 {2 Z- H2 }4 X5 O+ Ystudies, the possibility of retroviral
' h' v( a* e4 k. J& qinsertional mutagenesis, resulting
|" i @) |) y! V4 Iin the activation of other genes con-! N G& w2 ^5 A4 E
tributing to reprogramming, cannot 5 u8 K2 k* ?, D0 y+ u
be excluded, providing an opportu-
& R8 G+ d0 o- w; Q, I& ynity to potentially identify new repro- L' f, v$ [5 a( q, `; F2 u
gramming factors beyond the cur-
2 m% T- p1 k; {: E) Irent quartet. Also, taking a broader
( a: p3 l5 q1 Iscreening approach for reprogram-
) I1 K. Z6 C) C& R. Kming human fbroblasts (as Takahashi
3 S" c, Y8 _' ?3 }- U1 ^and Yamanaka did for their mouse
2 b( N0 X' I) _; m5 hstudy) might yield other combinations & A/ P* o6 Z. o, Z4 K' p
of reprogramming factors.
3 m X& N4 }: m! h0 NDirect reprogramming of somatic
, m _& }, i6 `- ycells to a pluripotent state, thus revers-; M4 `( y# x6 `( W$ ^& \' j c: Q# ?/ g0 {
ing the developmental arrow of time,
& z6 F6 e7 d( T0 ?is considered by some to be the “holy $ j2 i5 M6 ]) a" p1 R
grail” of stem cell research. Once the 3 ^3 y, m! ^1 z# I0 @0 q$ d3 X
results in human cells are confrmed, ) T' s+ W, r3 k- _
these advances will enable the cre-" d. s6 Z7 P! h9 d: Y- h
ation of patient-specifc stem cell lines
& }- k% \. o2 O* g; rto study different disease mechanisms
1 g' k7 {7 K+ X1 z5 B" Iin the laboratory. Such cellular models : f; H' g1 p; f/ l4 g+ w/ _3 d* s
also have the potential to dramatically ; w" j% X5 C7 Q
increase the effciency of drug discov-; T* y3 O* y1 F, i
ery and to provide valuable tools for
3 h% [! ^ m) C, X) f, o% ]toxicology testing. Furthermore, this
3 q, `+ v5 d6 h- k# greprogramming system could make ) U$ p! M V- c
the idea of customized patient-specifc
! n e( n0 F9 L0 n3 {4 gscreening and therapy both possible
! w, ?. S4 p+ ~+ Tand economically feasible. Finally, the 7 n7 `1 D! w4 ~% j5 L0 I0 ?
work will have a powerful impact on
% c, _- @) t$ e9 Tthe intense debate regarding the moral,
5 V q( J2 Z( R, I$ xreligious, and political aspects of ES cell 2 s1 p3 {1 S/ v. _6 g+ X6 ]
research. However, a big mistake now . i" j! _/ B- @. ~. a7 |
would be to consider human ES cells o, C) j3 I {$ O( Y
obsolete. There are still many hurdles / l6 S' m O) L; d! _/ q. `
to overcome before we ful ly understand
* A$ q" g- u, l" ]* ypluripotency and before we have human
- @" h) Q+ E0 Y1 _; EiPS cells in hand that are suitable for
; z6 S7 P1 Y; O8 O1 p2 ktherapeutic application. For example,
7 z# M) [+ a$ y \/ Ra signifcant proportion of mice derived
; e7 b7 z+ M8 H% h! c3 v8 yfrom mouse iPS cells develop tumors
3 N& }& |4 D+ q7 |1 n) p7 }# rdue to reactivation of the c-Myc retro-1 `) I. `4 s; E; `) \
virus (Okita et al., 2007) compared to
; j+ ]5 o, d: l4 B) X! S3 omice derived from ES cells, which are 2 H- Q; j/ w% M5 Y
normal. The search is now on to fnd a
0 E+ i: d7 ^* mway to reprogram somatic cells without
+ E3 v; V" f% }! q! Y3 \" Oretroviruses and maybe even using a $ R, Q4 L- Q1 d; ]/ h
cocktail of small molecules. Given this,
3 P; L+ `4 y% ]. S, B: P' L) Iit should be emphasized that human
|+ k) }' E4 U* P2 d: j8 mES cell research is more important than
4 \" |" j7 c, a* ]4 b. b: yever for it will shed light on how iPS
- Q% ~% Z1 g4 J( N* }8 icells can best be maintained in their
" p3 g" ]; ?: r$ H0 r7 Ipluripotent state and how they can be
: \+ i9 c/ z/ C$ d7 i, t4 i( Cinduced to differentiate into the cell
' T% R3 R1 G+ c: e1 x Blineage of interest. The feld of nuclear % x: O5 \7 z" f7 A' ]. ]' R
reprogramming has come a long way
+ k7 T9 U% r( L! x/ a. L9 O# nfrom the initial nuclear transplantation
- f- ]) x! f) k4 k4 i, ]: u5 Ustudies in frogs 50 years ago, to the S+ M) S7 Z0 ^$ `5 {
birth of Dolly, the frst mammal cloned
. A2 O, I& Y3 i* `' `from adult somatic cells (Wilmut et al.,
- Q+ }5 S- H- ]' I* @6 J0 f4 U1997), to the fallout from the fabricated
) Z2 ?- _, X" s: K/ S% q/ u6 B3 }% B, rhuman nuclear transfer experiments
! { `$ [- c. j" N* j2 \of several years ago, to the landmark 8 K+ d) t5 Y! l5 \* M% b/ R9 T2 r; Y
studies of Takahashi, Yamanaka, and % w% c1 O+ P" S
their colleagues, frst in mice and now ' s" p+ o7 P* F: d
in humans.# u% z2 e9 S3 D. `# i4 ]& q
ReFeRences3 t9 `' T6 k5 R9 @! v
Boyer, L.A., Lee, T.I., Cole, M.F., Johnstone, % x {) }( k: J o9 T$ v/ S3 C
S.E., Levine, S.S., Zucker, J.P., Guenther, + c' S( @% v! ?( j. S5 x+ C
M.G., Kumar, R.M., Murray, H.L., Jenner, R.G.,
; W9 O! n+ j$ o! `% Zet al. (2005). Cell 122, 947–956.) s+ ]+ `- L- B! J# F, [
Evans, M.J., and Kaufman, M.H. (1981). Na-
! R3 D# I& S8 F( Z' L8 m* Fture 292, 154–156.! h' _( s7 o+ @8 b$ I) L" [( P
Maherali, N., Sridharan, R., Xie, W., Utikal, J.,
" ]. T1 A( u# L3 D! e fEminli, S., Arnold, K., Stadtfeld, M., Yachenko, ' e5 c* K# U$ g6 m
R., Tchieu, J., Jaenisch, R., et al. (2007). Cell
/ H# V) L# ]. ]! [8 [& C/ LStem Cell 1, 55–70.7 w) s- t6 @6 o& C" Q
Martin, G.R. (1981). Proc. Natl. Acad. Sci. USA
. ?6 }5 z; O6 d/ u78, 7634–7638.
% I# M0 Z3 C1 c$ r0 J& `Okita, K., Ichisaka, T., and Yamanaka, S.
" D* ]6 R! e: [7 }(2007). Nature 448, 313–317.- u" t4 S6 I! ]3 D: B
Takahashi, K., and Yamanaka, S. (2006). Cell
. P6 h4 S& t% P ~126, 663–676.4 M9 d. d( ~: W t, }5 o* x
Takahashi, K., Tanabe, K., Ohnuki, M., Narita,
4 b7 U' a7 A9 u/ ?4 m8 @M., Ichisaka, T., Tomoda, K., and Yamanaka, S.
% g0 J$ x2 z, w6 J7 b- O(2007). Cell, this issue.
+ L" v, h6 @: D/ j+ q: dThomson, J.A., Itskovitz-Eldor, J., Shapiro, & J7 X$ u7 `) r7 j [
S.S., Waknitz, M.A., Swiergiel, J.J., Marshall, 9 b8 t# r8 U8 X8 z8 l
V.S., and Jones, J.M. (1998). Science 282, " @6 F0 H, c4 _) I. T2 t+ E& q
1145–1147.
' u+ L2 }9 ?5 K3 |9 c0 j- _Wernig, M., Meissner, A., Foreman, R., Bram-: D; F. l. ?/ \
brink, T., Ku, M., Hochedlinger, K., Bernstein,
/ y4 W2 Y3 }- A* }B.E., and Jaenisch, R. (2007). Nature 448,
9 ~7 T! Z; f( `: B$ @$ v& Z; k! F318–324.
7 f4 h& ^9 a0 m* ?Wilmut, I., Schnieke, A.E., McWhir, J., Kind,
" u7 a m2 e \2 ~% V/ T0 L9 rA.J., and Campbell, K.H. (1997). Nature 385, * Z( o/ E* ? ]& d' ^/ b4 X+ @3 Q. ~; P
810–813.
$ Q9 ^& S0 W: L2 xYamanaka, 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
