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本帖最后由 nanocellmatrix 于 2010-4-24 20:17 编辑 6 Y: O: c3 X$ I5 d3 y% T
n- @0 r& f; a3 s9 D$ A+ ~. JHarvard 的科学家证实将衰老的造血干细胞培养于年轻的Niche中，衰老的干细胞命运可以逆转。0 c% I, I/ u, ]' O H. M, X6 Y
对于这个问题的解答：不外乎stem cell intrinsic alterations 或 age-related changes in the stem cell supportive microenvironment/ niche.
( t' Q( s1 A$ |8 L' _) F, W8 y 研究发现，这种现象与niche细胞应答有关，同时与局部微环境中IGF的调节有关。! _& M/ o( D+ q& ]# t6 n: i: d" o
8 ?- _( V; o$ [- i) V8 f3 q/ G希望大家可以关于干细胞命运的逆转（ips，衰老，转分化等）探讨。3 ]4 Y- W+ r1 {
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Systemic signals regulate ageing and rejuvenation of blood stem cell niches) }" S2 ^$ L8 E) d d' i Y
Shane R. Mayack, Jennifer L. Shadrach, Francis S. Kim & Amy J. Wagers0 w) B: O1 U$ ^: Y( ]5 p
Department of Stem Cell and Regenerative Biology, Harvard University, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Joslin Diabetes Center, One Joslin Place, Boston, Massachusetts 02115, USA.; c+ Y. g/ G0 }. T( }! [
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Ageing in multicellular organisms typically involves a progressive decline in cell replacement and repair processes, resulting in several physiological deficiencies, including inefficient muscle repair, reduced bone mass, and dysregulation of blood formation (haematopoiesis). Although defects in tissue-resident stem cells clearly contribute to these phenotypes, it is unclear to what extent they reflect stem cell intrinsic alterations or age-related changes in the stem cell supportive
1 p v. V% `* B( r8 s7 e$ d# mmicroenvironment, or niche. Here, using complementary in vivo and in vitro heterochronic models, we show that age-associated changes in stem cell supportive niche cells deregulate normal haematopoiesis by causing haematopoietic stem cell dysfunction. Furthermore, we find that age-dependent defects in niche cells are systemically regulated and can be reversed by exposure to a young circulation or by neutralization of the conserved longevity regulator, insulin-like growth factor-1, in the marrow microenvironment. Together, these results show a new and critical role for local and systemic factors in signalling age-related haematopoietic decline, and highlight a new model in which blood-borne factors in aged animals act through local niche cells to induce age-dependent disruption of stem cell function. |
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发表于 2010-4-24 20:13
发表于 2010-5-17 17:54
