EMP Emergence from Hemogenic Endothelium in the Mammalian Yolk Sac Is Independent of Flow and Arterial Identity, but Is Regulated By Canonical Wnt Signaling

运行x1 生物 川地31 细胞生物学 内皮 祖细胞 干细胞 卵黄囊 血管母细胞 内皮干细胞 解剖 胚胎干细胞 造血 血管生成 免疫学 胚胎 癌症研究 遗传学 体外 基因
作者
Jenna M. Frame,Kathleen E. McGrath,Katherine H. Fegan,James Palis
出处
期刊:Blood [Elsevier BV]
卷期号:124 (21): 768-768 被引量:1
标识
DOI:10.1182/blood.v124.21.768.768
摘要

Abstract Hematopoietic stem cells (HSCs) emerge from arterial vessels of the mouse embryo through a Runx1-dependent process of endothelial-to-hematopoietic transition beginning at embryonic day 10.5 (E10.5). This arterial endothelial-to-hematopoietic transition is known to require embryonic circulation as well as beta-catenin signaling within the endothelial precursor, known as hemogenic endothelium. However, embryonic survival is dependent on the earlier emergence of a robust wave of yolk sac-derived definitive erythro-myeloid progenitors (EMPs), which have unilineage as well as multilineage potential, including high-proliferative potential colony forming cell (HPP-CFC) potential (Palis et al., PNAS, 2001). Like HSCs, EMP specification is dependent on Runx1, suggesting that they also emerge from a hemogenic endothelial precursor. However, the spatial localization of EMPs in the yolk sac and the mechanisms governing their emergence are not well understood. To visualize emerging EMPs in the yolk sac, we performed whole-mount immunohistochemistry for Kit, which we have demonstrated to contain nearly all EMP potential at E9.5. Kit+ cells coexpress Runx1 and CD31, and a subset have a polygonal/endothelial morphology, appear integrated into the vascular network, and are associated with rounded Kit+ cells in clusters, features consistent with an endothelial-to-hematopoietic transition. However, unlike HSCs, which emerge from major embryonic arteries, clusters of EMPs are located in larger and smaller caliber vessels in branches of both the arterial and venous vasculature, which is spatially organized within the yolk sac. To determine if EMP emergence from the vasculature is dependent on embryonic blood flow, which is required for HSC emergence, we analyzed the yolk sacs of Ncx1-null embryos, which fail to initiate heart contractions and subsequently lack embryonic circulation. Despite the lack of vascular remodeling in these circulation-deficient yolk sacs, Ncx1-null EMPs displayed normal cluster morphology, including both polygonal and rounded kit+ cells, indicating the endothelial-to-hematopoietic transition can occur without the mechanical influence of blood flow. To address whether EMP formation is responsive to other developmental signals, we utilized a yolk sac explant culture to evaluate the propensity of hemogenic endothelial cells to commit to hematopoiesis ex vivo. Culture of intact E8.5 yolk sacs for 48 hours with the canonical Wnt ligand Wnt3a resulted in an increase in both day 6-7 colony forming cells and day 13-14 HPP-CFC when compared with control yolk sacs. Preliminary treatment with Dkk1 alone did not adversely affect colony-forming activity when compared with untreated yolk sacs, and potentiation of endogenous canonical Wnt signaling with HLY78 did not augment colony production, suggesting that low levels of endogenous Wnt ligands are produced ex vivo. Despite the positive effect of Wnt3a on whole yolk sacs, treatment of isolated E9.5 Kit+CD41+CD16/32+ EMPs with Wnt3a did not increase colony formation, suggesting that Wnt signaling augments progenitor production at, or prior to, the hemogenic endothelial stage. Preliminary results utilizing imaging flow cytometry demonstrated increased beta-catenin intensity within the nuclear region in E9.5 Kit+VE-Cadherin/AA4.1+ endothelium following Wnt3a treatment, suggesting that hemogenic endothelial cells in the yolk sac are Wnt responsive. Consistent with this finding, in vitro Wnt3a treatment on primary E8.5-9.5 VE-Cadherin/AA4.1+CD16/32- endothelial cells resulted in upregulation of the beta-catenin target gene Axin2. To address whether Wnt signaling is endogenously active in vivo, we analyzed E8.5-E9 yolk sacs of BAT-gal reporter mice (Maretto et al., PNAS, 2003), and visualized a subset of cells with endothelial morphology expressing LacZ. Taken together, these data support the concept that EMPs, like HSCs, emerge from hemogenic endothelium. Surprisingly, this earlier endothelial-to-hematopoietic transition in the yolk sac is not dependent on blood flow or an arterial identity. However, similar to HSC emergence, EMP emergence from hemogenic endothelium is positively regulated by canonical Wnt signaling. These data highlight the presence of spatially, temporally, and functionally heterogeneous populations of hemogenic endothelium in the mammalian conceptus. Disclosures No relevant conflicts of interest to declare.

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
PDF的下载单位、IP信息已删除 (2025-6-4)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
刚刚
里面发布了新的文献求助10
1秒前
1秒前
ccccc完成签到,获得积分10
1秒前
儒雅冰岚完成签到,获得积分10
1秒前
彭于晏应助yoneyamai采纳,获得10
1秒前
1秒前
2秒前
2秒前
3秒前
daisy完成签到,获得积分10
3秒前
无限绿旋发布了新的文献求助10
3秒前
3秒前
3秒前
3秒前
4秒前
WQ发布了新的文献求助50
4秒前
机灵柚子应助苏桑焉采纳,获得20
5秒前
香蕉觅云应助自然的含烟采纳,获得10
5秒前
guoguo完成签到,获得积分10
7秒前
Z1987完成签到,获得积分10
7秒前
7秒前
无限的胜发布了新的文献求助10
7秒前
CodeCraft应助youlingduxiu采纳,获得10
7秒前
充电宝应助里面采纳,获得10
7秒前
无私的芹发布了新的文献求助10
7秒前
8秒前
追寻源智发布了新的文献求助10
8秒前
8秒前
yuanyuan发布了新的文献求助10
9秒前
NexusExplorer应助钟ZJ采纳,获得10
9秒前
发文章发布了新的文献求助10
10秒前
赘婿应助学术奴才采纳,获得10
10秒前
土亢土亢土完成签到,获得积分0
11秒前
11秒前
yoneyamai发布了新的文献求助10
13秒前
大个应助慕容雅柏采纳,获得10
13秒前
幸福的雪枫完成签到,获得积分10
14秒前
外向的忆霜完成签到,获得积分10
14秒前
fighting发布了新的文献求助10
14秒前
高分求助中
The Mother of All Tableaux Order, Equivalence, and Geometry in the Large-scale Structure of Optimality Theory 2400
Ophthalmic Equipment Market by Devices(surgical: vitreorentinal,IOLs,OVDs,contact lens,RGP lens,backflush,diagnostic&monitoring:OCT,actorefractor,keratometer,tonometer,ophthalmoscpe,OVD), End User,Buying Criteria-Global Forecast to2029 2000
Optimal Transport: A Comprehensive Introduction to Modeling, Analysis, Simulation, Applications 800
Official Methods of Analysis of AOAC INTERNATIONAL 600
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 588
T/CIET 1202-2025 可吸收再生氧化纤维素止血材料 500
Interpretation of Mass Spectra, Fourth Edition 500
热门求助领域 (近24小时)
化学 材料科学 医学 生物 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3951800
求助须知:如何正确求助?哪些是违规求助? 3497233
关于积分的说明 11086336
捐赠科研通 3227767
什么是DOI,文献DOI怎么找? 1784520
邀请新用户注册赠送积分活动 868692
科研通“疑难数据库(出版商)”最低求助积分说明 801163