本帖最后由 qgjin 于 2010-11-30 14:12 编辑 9 C( p7 Y. M. o. N, Z7 O4 {" X* ]
[attach]17740[/attach] l$ K' H, F* N8 ~The pregnancy hormones human chorionic gonadotropin and progesterone induce human embryonic stem cell proliferation and differentiation into neuroectodermal rosettes。/ ^% b7 m% U0 G% r! [! ?: l
Miguel J Gallego1†, Prashob Porayette1†, Maria M Kaltcheva1, Richard L Bowen2, Sivan Vadakkadath Meethal1,5, ) R" `: Y: R+ v% ZCraig S Atwood1,3,4*- @: a, e) x9 Q, \5 y6 }
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Abstract. D7 k! |* b4 f* }" v Introduction: The physiological signals that direct the division and differentiation of the zygote to form a- @7 G7 J7 O- H. i
blastocyst, and subsequent embryonic stem cell division and differentiation during early embryogenesis, are& \8 o# {4 `( J+ e
unknown. Although a number of growth factors, including the pregnancy-associated hormone human chorionic 7 A: d% T+ }# ~3 V! H" Egonadotropin (hCG) are secreted by trophoblasts that lie adjacent to the embryoblast in the blastocyst, it is not. b& ]6 a# b9 f# M
known whether these growth factors directly signal human embryonic stem cells (hESCs).( n1 H) c5 b/ c Methods: Here we used hESCs as a model of inner cell mass differentiation to examine the hormonal requirements * ^$ o& s+ _" _. L0 Z! p0 H% Ofor the formation of embryoid bodies (EB’s; akin to blastulation) and neuroectodermal rosettes (akin to neurulation).* P3 M6 P" g) u2 e Results: We found that hCG promotes the division of hESCs and their differentiation into EB’s and$ T3 e' v* q- ~0 x+ v
neuroectodermal rosettes. Inhibition of luteinizing hormone/chorionic gonadotropin receptor (LHCGR) signaling7 A( o4 c$ j- H0 q( c9 L% [
suppresses hESC proliferation, an effect that is reversed by treatment with hCG. hCG treatment rapidly upregulates+ T7 Q. F# ?6 J
steroidogenic acute regulatory protein (StAR)-mediated cholesterol transport and the synthesis of progesterone! L% D3 @! g" C/ H3 q. b) l8 t! m& A
(P4). hESCs express P4 receptor A, and treatment of hESC colonies with P4 induces neurulation, as demonstrated by ) O( d) h8 n3 D, ]the expression of nestin and the formation of columnar neuroectodermal cells that organize into neural tubelike C3 c8 D$ [+ C2 a+ q& N
rosettes. Suppression of P4 signaling by withdrawing P4 or treating with the P4-receptor antagonist RU-486 inhibits: R+ q+ V/ s2 S, Q
the differentiation of hESC colonies into EB’s and rosettes.. q* E/ [/ Y' ^5 d1 V* v- U w/ q5 a Conclusions: Our findings indicate that hCG signaling via LHCGR on hESC promotes proliferation and l6 l" M* M/ Z f- V
differentiation during blastulation and neurulation. These findings suggest that trophoblastic hCG secretion and / f# \3 M8 N6 ^( Gsignaling to the adjacent embryoblast could be the commencement of trophic support by placental tissues in the' c' M. U1 M. `- K
growth and development of the human embryo.作者: qingshui1985 时间: 2010-11-30 15:46