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本帖最后由 nanocellmatrix 于 2010-4-24 20:17 编辑 ' x8 i8 F2 A/ Q" }3 M1 J/ T& `
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Harvard 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。1 Y% V% ]% `$ m+ l7 Q3 @ u
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.
8 U& L! D$ ]( P) |3 f 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。
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% Z+ D6 x) a3 g/ `& G0 M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。 v \7 w% d5 P+ S! {! L# x# M5 d
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Systemic signals regulate ageing and rejuvenation of blood stem cell niches
7 H) M+ r8 Y# s1 k4 K% N* Q4 |Shane R. Mayack, Jennifer L. Shadrach, Francis S. Kim & Amy J. Wagers
/ e/ h/ T6 h4 l* }, l1 KDepartment 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., J' l7 x7 v- H) g
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4 K; l R/ |( v+ FAgeing 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
4 ~1 n2 _/ R3 I6 Rmicroenvironment, 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
