Ephrin-B2 has been shown to participate in angiogenesis, but the underlying mechanisms involved remain unclear. In this study, a rat model of local cerebral ischemia was prepared by focal middle cerebral artery occlus...Ephrin-B2 has been shown to participate in angiogenesis, but the underlying mechanisms involved remain unclear. In this study, a rat model of local cerebral ischemia was prepared by focal middle cerebral artery occlusion, followed by 24-hour reperfusion. Then, ephrin-B2 protein was administered intracerebroventricularly for 3 consecutive days via a micro-osmotic pump. Western blot assay and quantitative real-time reverse transcription PCR demonstrated the expression levels of angiopoietin-1 （Ang-1） mRNA and protein in the penumbra cortex of the ephrin-B2 treated group were decreased at day 4 after reperfusion, and increased at day 28, while the expression levels of angiopoietin-2 （Ang-2） were highly up-regulated at all time points tested. Double immunofluorescent staining indicated that Ang-1 and Ang-2 were both expressed in vascular endothelial cells positive for CD31. These findings indicate that ephrin-B2 influences the expressions of Ang-1 and Ang-2 during angiogenesis following transient focal cerebral ischemia.展开更多
AIM:Eph receptor tyrosine kinases and their membrane bound receptor-like ligands, the ephrins, represent a bi-directional cell-cell contact signaling system that directs epithelial movements in development. The meanin...AIM:Eph receptor tyrosine kinases and their membrane bound receptor-like ligands, the ephrins, represent a bi-directional cell-cell contact signaling system that directs epithelial movements in development. The meaning of this system in the adult human gut is unknown. We investigated the Eph/ephrin mRNA expression in the intestinal epithelium of healthy controls and patients with inflammatory bowel disease (IBD). METHODS: mRNA expression profiles of all Eph/ephrin family members in normal small intestine and colon were established by real-time RT-PCR. In addition, differential expression in IBD was investigated by cDNA array technology, and validated by both real-time RT-PCR and immunohistochemistry. Potential effects of enhanced EphB/ephrin-B signaling were analyzed in an in vitro IEC-6 cell scratch wound model. RESULTS: Human adult intestinal mucosa exhibits a complex pattern of Eph receptors and ephrins. Beside the known prominent co-expression of EphA2 and ephrinAl, we found abundantly co-expressed EphB2 and ephrin-B1/2. Interestingly, cDNA array data, validated by real-time PCR and immunohistochemistry, showed upregulation of ephrin-B2 in both perilesional and lesional intestinal epithelial cells of IBD patients, suggesting a role in epithelial homeostasis. Stimulation of ephrin-B signaling in ephrin- B1/2 expressing rat IEC-6-cells with recombinant EphB1-Fc resulted in a significant dose-dependent acceleration of wound closure. Furthermore, fluorescence microscopy showed that EphB1-Fc induced coordinated migration of wound edge cells is associated with enhanced formation of lamellipodial protrusions into the wound, increased actin stress fiber assembly and production of laminin at the wound edge. CONCLUSION: EphB/ephrin-B signaling might represent a novel protective mechanism that promotes intestinal epithelial wound healing, with potential impact on epithelial restitution in IBD.展开更多
OBJECTIVE Social anxiety disorder,also known as social phobia,is the most common of all anxiety disorders.Despite the seriousness of this disorder,it has rarely been studied and as a consequence,little is known about ...OBJECTIVE Social anxiety disorder,also known as social phobia,is the most common of all anxiety disorders.Despite the seriousness of this disorder,it has rarely been studied and as a consequence,little is known about its underlying neurobiology.Growing evidence suggests that inhibitory neurons dysfunction could affect the balance of neuronal activity in psychotic disorders including anxiety,SAD,etc.Ephrin-B(EB) proteins were previously demonstrated to ensure normal distribution and function of inhibitory interneurons in the brain.We thus proposed that deletion of EB2 in inhibitory neurons might destroy the homeostasis of excitatory neurons and inhibitory neurons,and induce behavioral deficits associated with psychotic diseases.METHODS(1)Mice.We generated conditional EB2 knockout mice as a model of SAD and characterized the behaviors and the biochemical changes in the brains of the knockout mice.We also generated a mouse line with a selective deletion of EB2 from vGAT neurons by breeding a v GAT-Cre line with a loxP-flanked alleles in EB2.For EB2 detection,we crossed vGAT-Cre;EphrinB2 loxp/loxp mice with Rosa26-STOP-tdTomato Cre indicator(Ai9) mice to label the vGAT neurons with tdTomato.Mice were maintained in a mixed CD1/129 genetic background.Al experiments involving mice were carried out in accordance with the Shanghai Jiaotong University.Genotypes were unlocked only after completion of analysis.(2) General procedures for behavioral testing.Open field test:Locomotor activity was measured using an open field test.The size of the open field box was 44 cm×44 cm×44 cm.Each mouse was placed in the corner of the open-field apparatus at the beginning of the test,and allowed to explore it for 15 min.The total distance traveled(in cm) and counts for stereotyped behaviors were recorded and analyzed.The total distance traveled was used as an index of locomotor activity.The percentage of center zone entries was considered as anxiety indexes.EPM test:The elevated plus maze apparatus was made of dark gray plastic and comprised two open arms(30 cm×7 cm×0.25 cm) opposed to two enclosed arms(30 cm × 7 cm × 15 cm) elevated60 cm from the floor.Animals were placed in the central area of the apparatus with their head facing an enclosed arm(test duration,5 min).Digitized video recordings with EthoVision software were used for behavioral analysis.The percentage of time spent in open arms and the percentage of open-arm entries were calculated.Social behaviors:Briefly,a top open acrylic box was divided into three compartments by two clear acrylic glass partitions with an opening in the bottom.Wire mesh cages that are either empty or have social stimulus mouse in it were put in the center of each outer compartment.Unfamiliar naive CD1/129 mice of the same age were used as stimulus mice.Prior to the test,the mouse was introduced into the center chamber for 5 min,with both gates closed.Gates were then open and the test mouse was acclimated to explore the empty three-chambered apparatus freely for another 10 min.After the initial 15 min habituation session,mice were placed in the center compartment and allowed to explore freely all the three compartments.To examine the social contact,the following activities were recorded via a video surveillance for 10 min.The number of entries to each compartment,the time spent in each compartment as well as the time and frequency each mouse spent in sniffing were analyzed with EthoVision XT 8.5(Noldus,Wageningen,Netherlands).RESULTS(1)Social preference assays were performed in WT-vGATCre,EB2-flox,and EB2-vGATCre mice respectively.To evaluate social approach behavior,we used a three-chamber social arena to evaluate animals for their social interaction.The control groups of WTvGATCre,EB2-flox mice showed a significant preference for spending time in the social chamber(P<0.05);whereas the EB2-vGATCre mice did not show this preference and spent roughly equal time in the social and nonsocial chambers.(2)To determine if the decrease in social preference could result from changes in locomotion,we compared locomotor activity in EB2-vG ATCre mice and control mice.We did not observe a significant lower locomotive activity in mice.Hence,EB2 deletion caused a change in social preference but not in locomotion.Taken together,EB2 deletion exerts abnormal psychotogenic activity of social deficits which was often considered as an important feature of SAD.(3) The time spent in the open arms is widely used to measure anxiety in mice,with greater time spent in the open arm being considered as less anxious behavior.To normalize for individual differences in overall activity level,the time spent in the open arms was divided by the total time.The ratio was higher for WT-vGATCre mice and EB2-loxp mice as compared to the EB2-vG ATCre mice(P=0.0112,P=0.0197).Thus,results showed that there was a change in anxiety levels from in EB2-vGATCre mice as compared with control mice.CONCLUSION EB2 may be a candidate risk gene for SAD and that the EB2 conditional knockout model could be a tool for studying the underlying mechanisms in SAD.展开更多
为了探讨局灶性脑缺血再灌注大鼠采用Ephrin-B2干预促进大鼠神经功能的恢复及作用机制,本研究选取了72只成年雄性SD大鼠,采用随机数字表法分为:空白组(等量生理盐水)、假手术组(等量生理盐水)、模型组(等量生理盐水)和干预组(Ephrin-B2...为了探讨局灶性脑缺血再灌注大鼠采用Ephrin-B2干预促进大鼠神经功能的恢复及作用机制,本研究选取了72只成年雄性SD大鼠,采用随机数字表法分为:空白组(等量生理盐水)、假手术组(等量生理盐水)、模型组(等量生理盐水)和干预组(Ephrin-B2连续干预3 d),每组各18只。通过对比各组大鼠神经功能评分,检测对比各组大鼠缺血侧大脑海马组织中血管细胞间黏附分子-1(VCAM-1)、核转录因子(NF-κB)蛋白、微血管密度的水平,检测并比较各组大鼠缺血侧海马组织中血管内皮生长因子(VEGF)m RNA及蛋白的表达水平,我们发现造模后第4、8、12、14天,干预组大鼠的神经功能评分显著的低于模型组(p<0.05);造模后第4、8、12、14天,干预组、模型组大鼠的缺血侧大脑海马组织中VCAM-1、NF-κB蛋白显著的高于空白组和假手术组(p<0.05);干预组大鼠的缺血侧大脑海马组织中VCAM-1、NF-κB蛋白显著的低于模型组(p<0.05);造模后第4、8、12、14天,干预组大鼠的缺血脑组织中微血管密度显著的高于模型组(p<0.05);造模后第4、8、12、14天,干预组、模型组大鼠的血侧脑组织VEGF m RNA及蛋白显著的高于空白组和假手术组(p<0.05);干预组大鼠的血侧脑组织VEGF m RNA及蛋白显著的高于模型组(p<0.05)。本研究表明,局灶性脑缺血再灌注大鼠采用Ephrin-B2干预能促进大鼠神经功能的恢复,可能与促进新生血管形成有关。展开更多
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
Background Although there were several clinical and experimental studies discussing the pathogenesis of dural arteriovenous fistula (DAVF), the pathological process leading to intracranial DAVF so far remains unknown ...Background Although there were several clinical and experimental studies discussing the pathogenesis of dural arteriovenous fistula (DAVF), the pathological process leading to intracranial DAVF so far remains unknown In this study, we investigated the expression of vascular growth factors in order to elucidate the possible role of these factors for the development of DAVF and to study the biological activity of this uncommon lesion Methods We examined the histological features, proliferative and angiogenic capacities of the tissue specimens obtained from 6 patients who underwent surgery at our institution Immunohistochemical staining for vascular endothelial growth factor (VEGF), its receptors Flk 1 and Flt 1, ephrin B2, MIB 1 and proliferating cell nuclear antigen (PCNA) was performed using standard immunohistochemical techniques Results A positive immunostaining was found for all antibodies studied except MIB 1, whereas nuclear endothelial expression of PCNA was observed in only 3/6 cases VEGF stained positive in all of the available specimens (6/6) Flk 1 showed a positive immunoreaction in only 2/6 cases and Flt 1 in 4/6 cases Ephrin B2 was expressed in the majority (5/6) of the cases Conclusions These results support the hypothesis that DAVFs might be acquired dynamic vascular malformations with low biological activity Vascular growth factors like VEGF and ephrin B2 might play a pivotal role in the formation of DAVF展开更多
文摘Ephrin-B2 has been shown to participate in angiogenesis, but the underlying mechanisms involved remain unclear. In this study, a rat model of local cerebral ischemia was prepared by focal middle cerebral artery occlusion, followed by 24-hour reperfusion. Then, ephrin-B2 protein was administered intracerebroventricularly for 3 consecutive days via a micro-osmotic pump. Western blot assay and quantitative real-time reverse transcription PCR demonstrated the expression levels of angiopoietin-1 （Ang-1） mRNA and protein in the penumbra cortex of the ephrin-B2 treated group were decreased at day 4 after reperfusion, and increased at day 28, while the expression levels of angiopoietin-2 （Ang-2） were highly up-regulated at all time points tested. Double immunofluorescent staining indicated that Ang-1 and Ang-2 were both expressed in vascular endothelial cells positive for CD31. These findings indicate that ephrin-B2 influences the expressions of Ang-1 and Ang-2 during angiogenesis following transient focal cerebral ischemia.
基金Supported by the Gennan Research Society (DFG-SFB 585/A8) and the Dr. Heinz Maurer Grant KFB 1.7
文摘AIM:Eph receptor tyrosine kinases and their membrane bound receptor-like ligands, the ephrins, represent a bi-directional cell-cell contact signaling system that directs epithelial movements in development. The meaning of this system in the adult human gut is unknown. We investigated the Eph/ephrin mRNA expression in the intestinal epithelium of healthy controls and patients with inflammatory bowel disease (IBD). METHODS: mRNA expression profiles of all Eph/ephrin family members in normal small intestine and colon were established by real-time RT-PCR. In addition, differential expression in IBD was investigated by cDNA array technology, and validated by both real-time RT-PCR and immunohistochemistry. Potential effects of enhanced EphB/ephrin-B signaling were analyzed in an in vitro IEC-6 cell scratch wound model. RESULTS: Human adult intestinal mucosa exhibits a complex pattern of Eph receptors and ephrins. Beside the known prominent co-expression of EphA2 and ephrinAl, we found abundantly co-expressed EphB2 and ephrin-B1/2. Interestingly, cDNA array data, validated by real-time PCR and immunohistochemistry, showed upregulation of ephrin-B2 in both perilesional and lesional intestinal epithelial cells of IBD patients, suggesting a role in epithelial homeostasis. Stimulation of ephrin-B signaling in ephrin- B1/2 expressing rat IEC-6-cells with recombinant EphB1-Fc resulted in a significant dose-dependent acceleration of wound closure. Furthermore, fluorescence microscopy showed that EphB1-Fc induced coordinated migration of wound edge cells is associated with enhanced formation of lamellipodial protrusions into the wound, increased actin stress fiber assembly and production of laminin at the wound edge. CONCLUSION: EphB/ephrin-B signaling might represent a novel protective mechanism that promotes intestinal epithelial wound healing, with potential impact on epithelial restitution in IBD.
基金National Natural Science Foundation of China (8150115381571326).
文摘OBJECTIVE Social anxiety disorder,also known as social phobia,is the most common of all anxiety disorders.Despite the seriousness of this disorder,it has rarely been studied and as a consequence,little is known about its underlying neurobiology.Growing evidence suggests that inhibitory neurons dysfunction could affect the balance of neuronal activity in psychotic disorders including anxiety,SAD,etc.Ephrin-B(EB) proteins were previously demonstrated to ensure normal distribution and function of inhibitory interneurons in the brain.We thus proposed that deletion of EB2 in inhibitory neurons might destroy the homeostasis of excitatory neurons and inhibitory neurons,and induce behavioral deficits associated with psychotic diseases.METHODS(1)Mice.We generated conditional EB2 knockout mice as a model of SAD and characterized the behaviors and the biochemical changes in the brains of the knockout mice.We also generated a mouse line with a selective deletion of EB2 from vGAT neurons by breeding a v GAT-Cre line with a loxP-flanked alleles in EB2.For EB2 detection,we crossed vGAT-Cre;EphrinB2 loxp/loxp mice with Rosa26-STOP-tdTomato Cre indicator(Ai9) mice to label the vGAT neurons with tdTomato.Mice were maintained in a mixed CD1/129 genetic background.Al experiments involving mice were carried out in accordance with the Shanghai Jiaotong University.Genotypes were unlocked only after completion of analysis.(2) General procedures for behavioral testing.Open field test:Locomotor activity was measured using an open field test.The size of the open field box was 44 cm×44 cm×44 cm.Each mouse was placed in the corner of the open-field apparatus at the beginning of the test,and allowed to explore it for 15 min.The total distance traveled(in cm) and counts for stereotyped behaviors were recorded and analyzed.The total distance traveled was used as an index of locomotor activity.The percentage of center zone entries was considered as anxiety indexes.EPM test:The elevated plus maze apparatus was made of dark gray plastic and comprised two open arms(30 cm×7 cm×0.25 cm) opposed to two enclosed arms(30 cm × 7 cm × 15 cm) elevated60 cm from the floor.Animals were placed in the central area of the apparatus with their head facing an enclosed arm(test duration,5 min).Digitized video recordings with EthoVision software were used for behavioral analysis.The percentage of time spent in open arms and the percentage of open-arm entries were calculated.Social behaviors:Briefly,a top open acrylic box was divided into three compartments by two clear acrylic glass partitions with an opening in the bottom.Wire mesh cages that are either empty or have social stimulus mouse in it were put in the center of each outer compartment.Unfamiliar naive CD1/129 mice of the same age were used as stimulus mice.Prior to the test,the mouse was introduced into the center chamber for 5 min,with both gates closed.Gates were then open and the test mouse was acclimated to explore the empty three-chambered apparatus freely for another 10 min.After the initial 15 min habituation session,mice were placed in the center compartment and allowed to explore freely all the three compartments.To examine the social contact,the following activities were recorded via a video surveillance for 10 min.The number of entries to each compartment,the time spent in each compartment as well as the time and frequency each mouse spent in sniffing were analyzed with EthoVision XT 8.5(Noldus,Wageningen,Netherlands).RESULTS(1)Social preference assays were performed in WT-vGATCre,EB2-flox,and EB2-vGATCre mice respectively.To evaluate social approach behavior,we used a three-chamber social arena to evaluate animals for their social interaction.The control groups of WTvGATCre,EB2-flox mice showed a significant preference for spending time in the social chamber(P<0.05);whereas the EB2-vGATCre mice did not show this preference and spent roughly equal time in the social and nonsocial chambers.(2)To determine if the decrease in social preference could result from changes in locomotion,we compared locomotor activity in EB2-vG ATCre mice and control mice.We did not observe a significant lower locomotive activity in mice.Hence,EB2 deletion caused a change in social preference but not in locomotion.Taken together,EB2 deletion exerts abnormal psychotogenic activity of social deficits which was often considered as an important feature of SAD.(3) The time spent in the open arms is widely used to measure anxiety in mice,with greater time spent in the open arm being considered as less anxious behavior.To normalize for individual differences in overall activity level,the time spent in the open arms was divided by the total time.The ratio was higher for WT-vGATCre mice and EB2-loxp mice as compared to the EB2-vG ATCre mice(P=0.0112,P=0.0197).Thus,results showed that there was a change in anxiety levels from in EB2-vGATCre mice as compared with control mice.CONCLUSION EB2 may be a candidate risk gene for SAD and that the EB2 conditional knockout model could be a tool for studying the underlying mechanisms in SAD.
文摘为了探讨局灶性脑缺血再灌注大鼠采用Ephrin-B2干预促进大鼠神经功能的恢复及作用机制,本研究选取了72只成年雄性SD大鼠,采用随机数字表法分为:空白组(等量生理盐水)、假手术组(等量生理盐水)、模型组(等量生理盐水)和干预组(Ephrin-B2连续干预3 d),每组各18只。通过对比各组大鼠神经功能评分,检测对比各组大鼠缺血侧大脑海马组织中血管细胞间黏附分子-1(VCAM-1)、核转录因子(NF-κB)蛋白、微血管密度的水平,检测并比较各组大鼠缺血侧海马组织中血管内皮生长因子(VEGF)m RNA及蛋白的表达水平,我们发现造模后第4、8、12、14天,干预组大鼠的神经功能评分显著的低于模型组(p<0.05);造模后第4、8、12、14天,干预组、模型组大鼠的缺血侧大脑海马组织中VCAM-1、NF-κB蛋白显著的高于空白组和假手术组(p<0.05);干预组大鼠的缺血侧大脑海马组织中VCAM-1、NF-κB蛋白显著的低于模型组(p<0.05);造模后第4、8、12、14天,干预组大鼠的缺血脑组织中微血管密度显著的高于模型组(p<0.05);造模后第4、8、12、14天,干预组、模型组大鼠的血侧脑组织VEGF m RNA及蛋白显著的高于空白组和假手术组(p<0.05);干预组大鼠的血侧脑组织VEGF m RNA及蛋白显著的高于模型组(p<0.05)。本研究表明,局灶性脑缺血再灌注大鼠采用Ephrin-B2干预能促进大鼠神经功能的恢复,可能与促进新生血管形成有关。
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.
文摘Background Although there were several clinical and experimental studies discussing the pathogenesis of dural arteriovenous fistula (DAVF), the pathological process leading to intracranial DAVF so far remains unknown In this study, we investigated the expression of vascular growth factors in order to elucidate the possible role of these factors for the development of DAVF and to study the biological activity of this uncommon lesion Methods We examined the histological features, proliferative and angiogenic capacities of the tissue specimens obtained from 6 patients who underwent surgery at our institution Immunohistochemical staining for vascular endothelial growth factor (VEGF), its receptors Flk 1 and Flt 1, ephrin B2, MIB 1 and proliferating cell nuclear antigen (PCNA) was performed using standard immunohistochemical techniques Results A positive immunostaining was found for all antibodies studied except MIB 1, whereas nuclear endothelial expression of PCNA was observed in only 3/6 cases VEGF stained positive in all of the available specimens (6/6) Flk 1 showed a positive immunoreaction in only 2/6 cases and Flt 1 in 4/6 cases Ephrin B2 was expressed in the majority (5/6) of the cases Conclusions These results support the hypothesis that DAVFs might be acquired dynamic vascular malformations with low biological activity Vascular growth factors like VEGF and ephrin B2 might play a pivotal role in the formation of DAVF
