iPS、胚胎干与直接转分化的“三国演义”

tpwang

xiaoheilong 发表于 2011-2-28 18:36 8 x- d9 I/ Q* ^( D0 C
化疗对人的副作用是毋庸置疑的，但他是癌症治疗中的常用的手段；“药皆三分毒”，但人类不会因此放弃延续改 ...

: F9 }( S: O& j# z# F道理虽如此，不过最好不要说病人忍受治疗方法的缺陷，不如说某些可控风险的考虑是可以因临床效应所接受的。干细胞这么复杂的活体进入体内治疗，风险只会比现有的化学药剂风险难控制。不过这个说法也得等到干细胞的研究与技术解决了很多“不稳定性”缺陷之后。也就是说风险的控制应该有一个底线，最好是明明白白的风险，而不是未知因素的未知风险。
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/ {: ~' b6 Y; y. A  m这倒不是iPS一家独有的课题，胚胎干也一样存在相关问题。即使所谓成体干细胞，如间充质，目前的临床“应用”也还存在很多应该能消除的“黑匣子”风险。

tpwang

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/ C! B# Q9 W  W7 I4 t7 t1 f% A一篇从分化结果来比较iPS和ESC的新文章# M" s$ Q: {  ?: R% H- j
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Epigenetic and Phenotypic Profile of Fibroblasts Derived from Induced Pluripotent Stem Cells
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iPS和ESC的一些差异是否必然会延续到分化过程以及分化结果，并在体内功能上会有差异，还没有定论。是否这些差异会在分化过程中消除或减弱，也是一种理论上的可能性。& f6 j0 e( i7 [+ O5 H2 M8 g

8 e, A  b4 c1 ?2 N7 [Human induced pluripotent stem (hiPS) cells offer a novel source of patient-specific cells for regenerative medicine. However, the biological potential of iPS-derived cells and their similarities to cells differentiated from human embryonic stem (hES) cells remain unclear. We derived fibroblast-like cells from two hiPS cell lines and show that their phenotypic properties and patterns of DNA methylation were similar to that of mature fibroblasts and to fibroblasts derived from hES cells. iPS-derived fibroblasts (iPDK) and their hES-derived counterparts (EDK) showed similar cell morphology throughout differentiation, and patterns of gene expression and cell surface markers were characteristic of mature fibroblasts. Arraybased methylation analysis was performed for EDK, iPDK and their parental hES and iPS cell lines, and hierarchical clustering revealed that EDK and iPDK had closely-related methylation profiles. DNA methylation analysis of promoter regions associated with extracellular matrix (ECM)-production (COL1A1) by iPS- and hESC-derived fibroblasts and fibroblast lineage commitment (PDGFRb), revealed promoter demethylation linked to their expression, and patterns of transcription and9 Q& ?! b4 v! g2 B
methylation of genes related to the functional properties of mature stromal cells were seen in both hiPS- and hES-derived fibroblasts. iPDK cells also showed functional properties analogous to those of hES-derived and mature fibroblasts, as seen by their capacity to direct the morphogenesis of engineered human skin equivalents. Characterization of the functional behavior of ES- and iPS-derived fibroblasts in engineered 3D tissues demonstrates the utility of this tissue platform to predict the capacity of iPS-derived cells before their therapeutic application.
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hyde

很多东西还是云里雾里的……加油了…………科学也是分久必合合久必分的……否则如何进步呢……

tpwang

回复 hyde 的帖子6 Y% ^* U2 ?2 ]6 L  v0 j  c, k
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要有打持久战的准备，发扬愚公移山的精神，为了全世界人民服务的精神，纪念白求恩治病的精神……

hyde

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7 u2 N! Q) V8 ~6 R, G; K7 w& R今天第二次听愚公移山了……第一次是听老板说……斗志突然燃烧起来了…………

hzq

fgh1124

我一直对“Hotspots of aberrant epigenomic reprogramming in human induced pluripotent stem cells ”同期的三篇文章是有怀疑的，老觉得实验设计不合理，他们就是在假设iPS 与ES 有差异的前提下去设计的实验，我觉得能找到差异是必然的。
2 X' K# K* d0 F) q+ i' U& y/ u反而我觉得最新cell stem cell 上的这篇文章“Background Mutations in Parental Cells Account for Most of the Genetic Heterogeneity of Induced Pluripotent Stem Cells” 更有意思。6 x' Q) t$ L, p; Z

" }' t% G; \: W3 s7 ]根据我的想法我们应该设计一个更大的实验，一劳永逸，解决关于Mutation 的争论：4 H, k- M3 d. a2 R: O
Genome Resequencing
0 ?4 G# F) f  k% z1. 供体细胞测序  r3 v& R% s$ I
2. 供体细胞形成的iPS 细胞系测序* K9 y- M: r* Y* w# a1 a
3. 供体细胞培养10，20， 30代测序# B% N, X. Y, a) g( A6 s# l1 R
4. 供体细胞形成的iPS 培养10, 20, 30 代测序# K& G' n; G- u) [) ]2 b7 B! R& M
5. 供体细胞形成的核移植细胞系测序  b# E" {; Q/ l
6. 建立的ES细胞系培养10, 20, 30 代测序
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通过这个设计可以解释的问题：  X: A3 R# K( @& w; G
1. iPS Mutation来自于供体细胞还是iPS 形成过程
% k- L! C6 G1 A6 m" J2. 细胞培养过程是否产生Mutation5 R) I. j0 V8 X- ]% I- x
3. iPS 在培养过程中的Mutation ratio 是否比ES 或者供体细胞 要高
1 e7 I$ t  D, h* P# Y4. iPS 与核移植哪种重编程方式更容易产生Mutation; J2 v5 s; l* }0 z% \! _8 S5 k
5. ES 的培养过程是否产生Mutation, k8 y( T$ T8 o& S3 w) Q
et al.....