2010年6月国内外干细胞研究最新进展

sususu

Progesterone induces adult mammary stem cell expansion
# w1 v. k4 W/ N, F6 @7 DNature Volume: 465, Pages: 803–807 Date published: (10 June 2010)
3 n' b. Y/ f, m! \1 [DOI: doi:10.1038/nature09091 . z& Z' C; a! B1 q
Reproductive history is the strongest risk factor for breast cancer after age, genetics and breast density1, 2. Increased breast cancer risk is entwined with a greater number of ovarian hormone-dependent reproductive cycles, yet the basis for this predisposition is unknown3, 4, 5. Mammary stem cells (MaSCs) are located within a specialized niche in the basal epithelial compartment that is under local and systemic regulation6. The emerging role of MaSCs in cancer initiation warrants the study of ovarian hormones in MaSC homeostasis. Here we show that the MaSC pool increases 14-fold during maximal progesterone levels at the luteal dioestrus phase of the mouse. Stem-cell-enriched CD49fhi cells amplify at dioestrus, or with exogenous progesterone, demonstrating a key role for progesterone in propelling this expansion. In aged mice, CD49fhi cells display stasis upon cessation of the reproductive cycle. Progesterone drives a series of events where luminal cells probably provide Wnt4 and RANKL signals to basal cells which in turn respond by upregulating their cognate receptors, transcriptional targets and cell cycle markers. Our findings uncover a dynamic role for progesterone in activating adult MaSCs within the mammary stem cell niche during the reproductive cycle, where MaSCs are putative targets for cell transformation events leading to breast cancer.
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; k- H( b" ]' u1 L1 U" Shttp://www.nature.com/nature/journal/v465/n7299/abs/nature09091.html

sususu

Ephrin-B2 controls VEGF-induced angiogenesis and lymphangiogenesis! O( d/ K, z) d% n, N( J# C# X
Nature Volume: 465, Pages: 483–486 Date published: 2010.6.
  h8 N7 u9 T5 Q: W9 IIn development, tissue regeneration or certain diseases, angiogenic growth leads to the expansion of blood vessels and the lymphatic vasculature. This involves endothelial cell proliferation as well as angiogenic sprouting, in which a subset of cells, termed tip cells, acquires motile, invasive behaviour and extends filopodial protrusions1, 2, 3. Although it is already appreciated that angiogenesis is triggered by tissue-derived signals, such as vascular endothelial growth factor (VEGF) family growth factors, the resulting signalling processes in endothelial cells are only partly understood. Here we show with genetic experiments in mouse and zebrafish that ephrin-B2, a transmembrane ligand for Eph receptor tyrosine kinases, promotes sprouting behaviour and motility in the angiogenic endothelium. We link this pro-angiogenic function to a crucial role of ephrin-B2 in the VEGF signalling pathway, which we have studied in detail for VEGFR3, the receptor for VEGF-C. In the absence of ephrin-B2, the internalization of VEGFR3 in cultured cells and mutant mice is defective, which compromises downstream signal transduction by the small GTPase Rac1, Akt and the mitogen-activated protein kinase Erk. Our results show that full VEGFR3 signalling is coupled to receptor internalization. Ephrin-B2 is a key regulator of this process and thereby controls angiogenic and lymphangiogenic growth., i% d9 E' v2 r% }$ l9 c
http://www.nature.com/nature/journal/v465/n7297/abs/nature09002.html

sususu

Ephrin-B2 regulates VEGFR2 function in developmental and tumour angiogenesis3 U% p2 ^9 n# X9 z2 K- j( W
http://www.nature.com/nature/journal/v465/n7297/abs/nature08995.html7 ?  z$ U3 [# H: G9 t
The formation and guidance of specialized endothelial tip cells is essential for both developmental and pathological angiogenesis1. Notch-1 signalling regulates the generation of tip cells, which respond to gradients of vascular endothelial growth factor (VEGF-A)2. The molecular cues and signalling pathways that control the guidance of tip cells are poorly understood. Bidirectional signalling by Eph receptors and ephrin ligands represents one of the most important guidance cues involved in axon path finding3. Here we show that ephrin-B2 reverse signalling involving PDZ interactions regulates endothelial tip cell guidance to control angiogenic sprouting and branching in physiological and pathological angiogenesis. In vivo, ephrin-B2 PDZ-signalling-deficient mice (ephrin-B2ΔV) exhibit a reduced number of tip cells with fewer filopodial extensions at the vascular front in the mouse retina. In pathological settings, impaired PDZ signalling decreases tumour vascularization and growth. Mechanistically, we show that ephrin-B2 controls VEGF receptor (VEGFR)-2 internalization and signalling. Importantly, internalization of VEGFR2 is necessary for activation and downstream signalling of the receptor and is required for VEGF-induced tip cell filopodial extension. Together, our results suggest that ephrin-B2 at the tip cell filopodia regulates the proper spatial activation of VEGFR2 endocytosis and signalling to direct filopodial extension. Blocking ephrin-B2 reverse signalling may be an attractive alternative or combinatorial anti-angiogenic therapy strategy to disrupt VEGFR2 function in tumour angiogenesis

sususu

中科院裴端卿研究组成功制造非“yamanaka factor”的iPS细胞。虽然已经不是那么令人supprising了，但还是不错。这个研究组一直出了不少好文章。
) |3 r# K# J- t' ?& j3 z+ z- s从题目即可看出大意，E-cadherin介导的细胞接触对ips制作非常重要。
$ j9 t9 L5 \5 M& g* S（关于Cadherin，我以后另做介绍，这是一个非常重要的蛋白家族）
8 z7 x8 h- h+ \Stem Cells. 2010 Jun 2. [Epub ahead of print]9 t+ t4 m8 ]$ o( s; U
E-cadherin-Mediated Cell-Cell Contact is Critical for Induced Pluripotent Stem Cell Generation.
- m. ^  y4 f2 O& z+ A+ H$ IChen T, Yuan D, Wei B, Jiang J, Kang J, Ling K, Gu Y, Li J, Xiao L, Pei G.( k; V1 t! ~7 P! _. X
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Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.- L& G) i. _- E! x" r& b4 a/ T: X
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The low efficiency of reprogramming and genomic integration of virus vectors obscure the potential application of induced pluripotent stem (iPS) cells; therefore, identification of chemicals and cooperative factors that may improve the generation of iPS cells will be of great value. Moreover, the cellular mechanisms that limit the reprogramming efficiency need to be investigated. Through screening a chemical library we found that two chemicals reported to upregulate E-cadherin considerably increase the reprogramming efficiency. Further study of the process indicated that E-cadherin is upregulated during reprogramming and the established iPS cells possess E-cadherin-mediated cell-cell contact, morphologically indistinguishable from ES cells. Our experiments also demonstrate that overexpression of E-cadherin significantly enhances reprogramming efficiency, whereas knockdown of endogenous E-cadherin by shRNA reduces the efficiency. Consistently, abrogation of cell-cell contact by the inhibitory peptide or the neutralizing antibody against the extracellular domain of E-cadherin compromises iPS cell generation. Further mechanistic study reveals that adhesive binding activity of E-cadherin is required. Our results highlight the critical role of E-cadherin-mediated cell-cell contact in reprogramming and suggest new routes for more efficient iPS cell generation.

sususu

日本理化学研究所（RIKEN）的古関明彦研究组和谷口克研究组使用小鼠ips成功分化natural killer T细胞，并且确认这些细胞的in vivo抗肿瘤作用。非常有意义的工作。4 k! B3 e4 A  u' j

, N0 d5 j/ r6 g/ S- g* u" |0 h& TJ Clin Invest. 2010 Jun 1. pii: 42027. doi: 10.1172/JCI42027. [Epub ahead of print]
0 g- I, k: K5 f! \+ d# zMurine induced pluripotent stem cells can be derived from and differentiate into natural killer T cells.7 t9 Q6 l* L1 v5 k
Watarai H, Fujii SI, Yamada D, Rybouchkin A, Sakata S, Nagata Y, Iida-Kobayashi M, Sekine-Kondo E, Shimizu K, Shozaki Y, Sharif J, Matsuda M, Mochiduki S, Hasegawa T, Kitahara G, Endo TA, Toyoda T, Ohara O, Harigaya KI, Koseki H, Taniguchi M.
. O. H5 ]4 D4 \http://www.ncbi.nlm.nih.gov/pubmed/20516640?dopt=Abstract
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) S. R0 v$ k- Z; {2 jNKT cells demonstrate antitumor activity when activated to produce Th1 cytokines by DCs loaded with alpha-galactosylceramide, the prototypic NKT cell-activating glycolipid antigen. However, most patients do not have sufficient numbers of NKT cells to induce an effective immune response in this context, indicating a need for a source of NKT cells that could be used to supplement the endogenous cell population. Induced pluripotent stem cells (iPSCs) hold tremendous potential for cell-replacement therapy, but whether it is possible to generate functionally competent NKT cells from iPSCs has not been rigorously assessed. In this study, we successfully derived iPSCs both from embryonic fibroblasts from mice harboring functional NKT cell-specific rearranged T cell receptor loci in the germline and from splenic NKT cells from WT adult mice. These iPSCs could be differentiated into NKT cells in vitro and secreted large amounts of the Th1 cytokine IFN-gamma. Importantly, iPSC-derived NKT cells recapitulated the known adjuvant effects of natural NKT cells and suppressed tumor growth in vivo. These studies demonstrate the feasibility of expanding functionally competent NKT cells via an iPSC phase, an approach that may be adapted for NKT cell-targeted therapy in humans.

sususu

日本理化学研究所（RIKEN）的古関明彦研究组和谷口克研究组使用小鼠ips成功分化natural killer T细胞，并且确认这些细胞的in vivo抗肿瘤作用。非常有意义的工作。2 ~1 r7 {7 J% u$ V" z0 d

+ w& D. n; D& MJ Clin Invest. 2010 Jun 1. pii: 42027. doi: 10.1172/JCI42027. [Epub ahead of print]
* [, w, U' ^5 c+ p( e" WMurine induced pluripotent stem cells can be derived from and differentiate into natural killer T cells.9 K9 u6 W9 ^9 u1 ^3 U% P, U
Watarai H, Fujii SI, Yamada D, Rybouchkin A, Sakata S, Nagata Y, Iida-Kobayashi M, Sekine-Kondo E, Shimizu K, Shozaki Y, Sharif J, Matsuda M, Mochiduki S, Hasegawa T, Kitahara G, Endo TA, Toyoda T, Ohara O, Harigaya KI, Koseki H, Taniguchi M.
8 x+ O8 |! J5 }8 M0 j% t7 R- K( N  Chttp://www.ncbi.nlm.nih.gov/pubmed/20516640?dopt=Abstract, K# q# c" {: m/ E* X
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NKT cells demonstrate antitumor activity when activated to produce Th1 cytokines by DCs loaded with alpha-galactosylceramide, the prototypic NKT cell-activating glycolipid antigen. However, most patients do not have sufficient numbers of NKT cells to induce an effective immune response in this context, indicating a need for a source of NKT cells that could be used to supplement the endogenous cell population. Induced pluripotent stem cells (iPSCs) hold tremendous potential for cell-replacement therapy, but whether it is possible to generate functionally competent NKT cells from iPSCs has not been rigorously assessed. In this study, we successfully derived iPSCs both from embryonic fibroblasts from mice harboring functional NKT cell-specific rearranged T cell receptor loci in the germline and from splenic NKT cells from WT adult mice. These iPSCs could be differentiated into NKT cells in vitro and secreted large amounts of the Th1 cytokine IFN-gamma. Importantly, iPSC-derived NKT cells recapitulated the known adjuvant effects of natural NKT cells and suppressed tumor growth in vivo. These studies demonstrate the feasibility of expanding functionally competent NKT cells via an iPSC phase, an approach that may be adapted for NKT cell-targeted therapy in humans.

sususu

在5月30号发表在nature biotechnology的一篇文章，介绍了使用重组人laminin-511能长期培养扩增人ES或iPS细胞，而且是Feeder free——这对以后的临床应用十分关键。
! ~% F! \& x" v9 jNat Biotechnol. 2010 May 30. [Epub ahead of print]
3 R' ], r& ?6 d- R' M0 p9 vLong-term self-renewal of human pluripotent stem cells on human recombinant laminin-511.
$ v! L3 o) y# z6 K' TRodin S, Domogatskaya A, Ström S, Hansson EM, Chien KR, Inzunza J, Hovatta O, Tryggvason K.  f% Y; m' i  `' F7 {
http://www.ncbi.nlm.nih.gov/pubmed/20512123?dopt=Abstract
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We describe a system for culturing human embryonic stem (hES) cells and induced pluripotent stem (iPS) cells on a recombinant form of human laminin-511, a component of the natural hES cell niche. The system is devoid of animal products and feeder cells and contains only one undefined component, human albumin. The hES cells self-renewed with normal karyotype for at least 4 months (20 passages), after which the cells could produce teratomas containing cell lineages of all three germ layers. When plated on laminin-511 in small clumps, hES cells spread out in a monolayer, maintaining cellular homogeneity with approximately 97% OCT4-positive cells. Adhesion of hES cells was dependent on alpha6beta1 integrin. The use of homogeneous monolayer hES or iPS cell cultures provides more controllable conditions for the design of differentiation methods. This xeno-free and feeder-free system may be useful for the development of cell lineages for therapeutic purposes.

sususu

广州中山医大眼科中心葛坚研究组发表了一篇有意义的文章，关于ips细胞分化为视网膜神经节细胞，并且通过玻璃体注射方式进行移植后发现能够存活。应该说是非常不错的工作。+ n1 H0 F5 x. |9 k/ A1 f- R! R* Y
Invest Ophthalmol Vis Sci. 2010 May 19. [Epub ahead of print]  Z6 q% G! Z% a1 ^9 k8 x
Generation of Retinal Ganglion-Like Cells from Reprogrammed Mouse Fibroblasts.1 H8 H7 C. _9 R; R; F, \
Chen M, Chen Q, Sun X, Shen W, Liu B, Zhong XF, Leng Y, Li C, Zhang W, Chai F, Huang B, Gao Q, Xiang AP, Zhuo Y, Ge J.
; G0 I; b% T5 _" O0 {http://www.ncbi.nlm.nih.gov/pubmed/20484577?dopt=Abstract
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PURPOSE. Somatic cells can be reprogrammed into ES-like pluripotent state by Oct-3/4, Sox2, c-Myc and Klf4. Sox2 as an essential reprogramming factor, also contributes to the development of eye and retina. This study was to determine whether induced pluripotent stem (iPS) cells express retinal progenitor cell (RPC) related genes, and whether iPS cells can directly differentiate into retinal ganglion cells (RGCs). METHODS. Mouse iPS cells were induced by ectopically express the four factors in tail-tip fibroblasts (TTFs). The expression of RPC related genes in iPS cells was analyzed by RT-PCR and immunofluorescence. iPS cells were induced to differentiate into RGCs by the addition of Dkk1 + Noggin (DN) + DAPT and overexpression of Math5. iPS-derived RGC-like cells were injected into retina, and the eyes were analyzed by immunohistochemistry. RESULTS. iPS cells inherently express RPC related genes such as Pax6, Rx, Otx2, Lhx2, and Nestin. Overexpression of Math5 and addition of DN can directly differentiate iPS into retinal ganglion-like cells. These iPS derived RGC-like cells display long synapses and gene expression pattern including Math5, Brn3b, Islet-1 and Thy1.2. Furthermore, inhibiting Hes1 by DAPT increases the expression of RGC marker genes. In addition, iPS derived RGC-like cells were able to survive but unable integrated into normal retina after transplantation. CONCLUSION. The four factors induced iPS cell inherently express RPC related genes, and iPS cell fate can be further turned into RGC-like cell by regulating transcription factors expression. Our findings demonstrate that iPS cells are valuable for regeneration research of retina degeneration diseases.

tspaulzhao

Good job. Thanks.

lingn

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中科院裴端卿研究组成功制造非“yamanaka factor”的iPS细胞。虽然已经不是那么令人supprising了，但还是不 ...) U5 c: K; H0 ]* j
sususu 发表于 2010-6-30 16:18

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Ding sheng在PNAS上有一篇文章和这个有点类似，发现human ESC更多的依赖E-cadherin，比较少的依赖integrin。) w: y- H$ h3 L! y6 G8 G
Proc Natl Acad Sci U S A. 2010 May 4;107(18):8129-34. Epub 2010 Apr 20.
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4 A6 F# _2 n+ r6 J5 \Revealing a core signaling regulatory mechanism for pluripotent stem cell survival and self-renewal by small molecules.
6 U& k" X' W6 Z1 S( x3 TXu Y, Zhu X, Hahm HS, Wei W, Hao E, Hayek A, Ding S.$ K% ^3 W; L) V; C
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Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.2 h/ Q: `- a& f. m; Q# V3 x

$ O- R& Z+ E' `# YAbstract9 t8 J2 i: O0 I$ i
Using a high-throughput chemical screen, we identified two small molecules that enhance the survival of human embryonic stem cells (hESCs). By characterizing their mechanisms of action, we discovered an essential role of E-cadherin signaling for ESC survival. Specifically, we showed that the primary cause of hESC death following enzymatic dissociation comes from an irreparable disruption of E-cadherin signaling, which then leads to a fatal perturbation of integrin signaling. Furthermore, we found that stability of E-cadherin and the resulting survival of ESCs were controlled by specific growth factor signaling. Finally, we generated mESC-like hESCs by culturing them in mESC conditions. And these converted hESCs rely more on E-cadherin signaling and significantly less on integrin signaling. Our data suggest that differential usage of cell adhesion systems by ESCs to maintain self-renewal may explain their profound differences in terms of morphology, growth factor requirement, and sensitivity to enzymatic cell dissociation.
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