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本帖最后由 nanocellmatrix 于 2010-4-24 20:17 编辑
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/ |/ S* ^/ d3 b9 g9 L' wHarvard 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。6 p: R" K, c4 G
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.
" {% \; Q. e) u* x, Y2 R 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。4 f( c7 M( n8 r. c1 f$ D
9 \$ K5 I; u. o; B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。
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- y) b6 y# j6 J$ R$ mSystemic signals regulate ageing and rejuvenation of blood stem cell niches4 N1 E: O; |. |8 E' s
Shane R. Mayack, Jennifer L. Shadrach, Francis S. Kim & Amy J. Wagers* Y& I( A/ N1 H, m
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.
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9 @ e8 e! t* N$ `+ B5 |% wAgeing 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
( Z8 @0 u, e! x, e# l5 v4 wmicroenvironment, 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
