Postmitotic neurons in the neocortex migrate to appropriate positions and form layered structures of nascent cortex during brain development. The migration of these neurons requires precise control and coordination of...Postmitotic neurons in the neocortex migrate to appropriate positions and form layered structures of nascent cortex during brain development. The migration of these neurons requires precise control and coordination of a large number of molecules such as axon guidance cues. The Eph-ephrin signaling pathway plays important roles in the development of the nervous system in a wide variety of ways, including cell segregation, axon pathfinding, and neuron migration. However, the role of ephrin-B2/ EphA4 signaling in cortical neuron migration remains elusive. Here we demonstrated that ephrin-B2 and its receptor EphA4 were expressed in complementary and overlapping patterns in the developing neocortex. Deletion of the EphA4 gene in the embryonic cerebral cortex resulted in faster migration of cortical neurons, whereas knockdown or overexpression of ephdn-B2 did not alter the normal process of migration. These results suggest that ephrin-B2 forward signaling through EphA4 is required for the precise control of cortical neuron migration.展开更多
Objective： To evaluate the effect of Xuefu Zhuyu Capsule（血府逐瘀胶囊）-containing serum（XFZY-CS） on Eph B4/ephrin B2 and its reverse signal in human microvascular endothelial cell-1（HMEC-1）. Methods： XFZY-CS a...Objective： To evaluate the effect of Xuefu Zhuyu Capsule（血府逐瘀胶囊）-containing serum（XFZY-CS） on Eph B4/ephrin B2 and its reverse signal in human microvascular endothelial cell-1（HMEC-1）. Methods： XFZY-CS and the blank control serum were collected. HMEC-1 cells were randomly assigned to 6 groups including the concentration 1.25%, 2.5%, and 5% XFZY-CS groups and their blank serum control ones. The angiogenesis effect of XFZY-CS was tested with an in vitro tube formation assay and the best condition of pro-angiogenesis was determined. The effect of XFZY-CS on Eph B4/ephrin B2 and the reverse signal were determined by Western blot and real-time quantitative polymerase chain reaction, respectively; we also confirmed the results through activating and inhibiting the reverse signal by Eph B4/fc and pyrophosphatase/phosphodiesterase2（PP2）. Results： XFZY-CS promoted angiogenesis at the concentration of 2.5% corresponding serum after being cultured for 48 h, while inhibited angiogenesis at the concentration of 5% after culturing for 48 and 72 h. Under the 2.5% serum concentration, XFZY up-regulated the expression of Eph B4-m RNA at 12 h（P〈0.05）, and down-regulates its expression at 24 h（P〈0.01）. Protein expression of Eph B4 was apparently up-regulated at 12 h and down-regulated at 24 h. The phosphorylation of ephrin B2 increased at 9 h（P〈0.05）. In addition, 2.5% XFZY-CS played a similar role as the reverse signaling activator Eph B4/Fc ranging from 0.5 to 5 μg/m L（P〉0.05）. XFZY-CS also reduced the inhibitive effect of PP2 in limited periods. Conclusion： Eph B4/ephrin B2 was the upstream signal in the process of angiogenesis and its reverse signaling was responsible for XFZY＇s effect on promoting angiogenesis.展开更多
基金supported by grants from the Chinese Academy of Sciencesthe National Basic Research Development Program of China (2011CB504102)the National Natural Science Foundation of China (31123002 and 31321091)
文摘Postmitotic neurons in the neocortex migrate to appropriate positions and form layered structures of nascent cortex during brain development. The migration of these neurons requires precise control and coordination of a large number of molecules such as axon guidance cues. The Eph-ephrin signaling pathway plays important roles in the development of the nervous system in a wide variety of ways, including cell segregation, axon pathfinding, and neuron migration. However, the role of ephrin-B2/ EphA4 signaling in cortical neuron migration remains elusive. Here we demonstrated that ephrin-B2 and its receptor EphA4 were expressed in complementary and overlapping patterns in the developing neocortex. Deletion of the EphA4 gene in the embryonic cerebral cortex resulted in faster migration of cortical neurons, whereas knockdown or overexpression of ephdn-B2 did not alter the normal process of migration. These results suggest that ephrin-B2 forward signaling through EphA4 is required for the precise control of cortical neuron migration.
基金Supported by the National Natural Science Foundation of China(No.81072933 and No.81173431)National Center for Complementary and Alternative Medicine/National Institutes of Health of USA(No.2K24 AT004095)
文摘Objective： To evaluate the effect of Xuefu Zhuyu Capsule（血府逐瘀胶囊）-containing serum（XFZY-CS） on Eph B4/ephrin B2 and its reverse signal in human microvascular endothelial cell-1（HMEC-1）. Methods： XFZY-CS and the blank control serum were collected. HMEC-1 cells were randomly assigned to 6 groups including the concentration 1.25%, 2.5%, and 5% XFZY-CS groups and their blank serum control ones. The angiogenesis effect of XFZY-CS was tested with an in vitro tube formation assay and the best condition of pro-angiogenesis was determined. The effect of XFZY-CS on Eph B4/ephrin B2 and the reverse signal were determined by Western blot and real-time quantitative polymerase chain reaction, respectively; we also confirmed the results through activating and inhibiting the reverse signal by Eph B4/fc and pyrophosphatase/phosphodiesterase2（PP2）. Results： XFZY-CS promoted angiogenesis at the concentration of 2.5% corresponding serum after being cultured for 48 h, while inhibited angiogenesis at the concentration of 5% after culturing for 48 and 72 h. Under the 2.5% serum concentration, XFZY up-regulated the expression of Eph B4-m RNA at 12 h（P〈0.05）, and down-regulates its expression at 24 h（P〈0.01）. Protein expression of Eph B4 was apparently up-regulated at 12 h and down-regulated at 24 h. The phosphorylation of ephrin B2 increased at 9 h（P〈0.05）. In addition, 2.5% XFZY-CS played a similar role as the reverse signaling activator Eph B4/Fc ranging from 0.5 to 5 μg/m L（P〉0.05）. XFZY-CS also reduced the inhibitive effect of PP2 in limited periods. Conclusion： Eph B4/ephrin B2 was the upstream signal in the process of angiogenesis and its reverse signaling was responsible for XFZY＇s effect on promoting angiogenesis.
