本帖最后由 qgjin 于 2010-11-30 14:12 编辑 5 O3 k8 l) i, ^4 G% e5 o 1 Z3 A: B) m% m4 g7 m[attach]17740[/attach] ; l3 s l1 D+ [" n9 P9 @The pregnancy hormones human chorionic gonadotropin and progesterone induce human embryonic stem cell proliferation and differentiation into neuroectodermal rosettes。 ! A4 y* `, g* m7 l6 a/ oMiguel J Gallego1†, Prashob Porayette1†, Maria M Kaltcheva1, Richard L Bowen2, Sivan Vadakkadath Meethal1,5, ; a. [6 z; k Y! S& q5 wCraig S Atwood1,3,4*6 W9 M+ a9 ^) c; V7 o9 a( O) O
1 `$ u$ Y0 q& c/ L& AAbstract8 ~! F4 k7 y2 H( q% O I! [ Introduction: The physiological signals that direct the division and differentiation of the zygote to form a ( |9 N) l7 ^! J, \8 ~( A% zblastocyst, and subsequent embryonic stem cell division and differentiation during early embryogenesis, are ) g; S7 U Q Z* d9 c% ~ y2 qunknown. Although a number of growth factors, including the pregnancy-associated hormone human chorionic9 t- p5 C6 o/ B
gonadotropin (hCG) are secreted by trophoblasts that lie adjacent to the embryoblast in the blastocyst, it is not $ a* m% E3 T- Q6 Q9 i! lknown whether these growth factors directly signal human embryonic stem cells (hESCs). n: `7 U. c% o$ s Methods: Here we used hESCs as a model of inner cell mass differentiation to examine the hormonal requirements3 D1 \2 k+ L/ p2 X3 V6 U! b% B
for the formation of embryoid bodies (EB’s; akin to blastulation) and neuroectodermal rosettes (akin to neurulation).6 C& z; p5 J0 m# q; }6 d! e Results: We found that hCG promotes the division of hESCs and their differentiation into EB’s and0 J% N7 _2 b& g g
neuroectodermal rosettes. Inhibition of luteinizing hormone/chorionic gonadotropin receptor (LHCGR) signaling ; a2 w' O7 D) b& d2 l- Psuppresses hESC proliferation, an effect that is reversed by treatment with hCG. hCG treatment rapidly upregulates5 ^; c0 W# A' A. u
steroidogenic acute regulatory protein (StAR)-mediated cholesterol transport and the synthesis of progesterone) T8 J* m0 G, s0 |, R2 `" U
(P4). hESCs express P4 receptor A, and treatment of hESC colonies with P4 induces neurulation, as demonstrated by . D3 X6 H, l+ H8 d1 gthe expression of nestin and the formation of columnar neuroectodermal cells that organize into neural tubelike! ?) Y4 s; q7 n
rosettes. Suppression of P4 signaling by withdrawing P4 or treating with the P4-receptor antagonist RU-486 inhibits* c0 R' g, ~) n3 j) G. d, Q
the differentiation of hESC colonies into EB’s and rosettes.- V. B8 E' {# d# m7 B Conclusions: Our findings indicate that hCG signaling via LHCGR on hESC promotes proliferation and* m# d* {, T% \3 k, d; l
differentiation during blastulation and neurulation. These findings suggest that trophoblastic hCG secretion and + N8 d2 |9 H7 Hsignaling to the adjacent embryoblast could be the commencement of trophic support by placental tissues in the 7 |. T" }& Q; V& T- e, Wgrowth and development of the human embryo.作者: qingshui1985 时间: 2010-11-30 15:46