Nkx2.5 marks angioblasts that contribute to hemogenic endothelium of the endocardium and dorsal aorta
- Weizmann Institute of Science, Israel
- Victor Chang Cardiac Research Institute, Australia
- Technion-Israel Institute of Technology, Israel
- Chinese Academy of Sciences, China
- The University of Washington, United States
- The University of Queensland, Australia
- The University of Sydney, Australia
Abstract
Novel regenerative therapies may stem from deeper understanding of the mechanisms governing cardiovascular lineage diversification. Using enhancer mapping and live imaging in avian embryos, and genetic lineage tracing in mice, we investigated the spatio-temporal dynamics of cardiovascular progenitor populations. We show that expression of the cardiac transcription factor Nkx2.5 marks a mesodermal population outside of the cardiac crescent in the extraembryonic and lateral plate mesoderm, with characteristics of hemogenic angioblasts. Extra-cardiac Nkx2.5 lineage progenitors migrate into the embryo and contribute to clusters of CD41+/CD45+ and RUNX1+ cells in the endocardium, the aorta-gonad-mesonephros region of the dorsal aorta and liver. We also demonstrated that ectopic expression of Nkx2.5 in chick embryos activates the hemoangiogenic gene expression program. Taken together, we identified a hemogenic angioblast cell lineage characterized by transient Nkx2.5 expression that contributes to hemogenic endothelium and endocardium, suggesting a novel role for Nkx2.5 in hemoangiogenic lineage specification and diversification.
Data availability
-
Stereo-sequencing: 3D Transcriptome of the mouse embryo at gastrulationPublicly available at the NCBI Gene Expression Omnibus (accession no: GSE65924).
-
Single Cell Expression Profiling Resolves the Transcriptional Programs of Early Mesoderm DiversificationPublicly available at the NCBI Gene Expression Omnibus (accession no: GSE74994).
Article and author information
Author details
Funding
Israel Science Foundation
- Lyad Zamir
- Elisha Nathan
- Oren Yifa
- Eldad Tzahor
National Health and Medical Research Council (1074386,573732,1110751)
- Reena Singh
- Ralph Patrick
- Patrick PL Tam
- Richard P Harvey
Stem Cells Australia (SR110001002)
- Reena Singh
- Ralph Patrick
- Richard P Harvey
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Kari Alitalo, University of Helsinki, Finland
Ethics
Animal experimentation: Mice used in this study were bred and maintained in the Victor Chang Cardiac Research Institute BioCore facility according to the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes.Use of chick embryos before embryonic Day 21 does not require IACUC approval.
Version history
- Received: August 26, 2016
- Accepted: March 6, 2017
- Accepted Manuscript published: March 8, 2017 (version 1)
- Version of Record published: April 21, 2017 (version 2)
Copyright
© 2017, Zamir et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 3,038
- views
-
- 681
- downloads
-
- 25
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Nkx2.5 marks angioblasts that contribute to hemogenic endothelium of the endocardium and dorsal aorta
eLife 6:e20994.
https://doi.org/10.7554/eLife.20994
Further reading
-
- Computational and Systems Biology
- Developmental Biology
The gain-of-function mutation in the TALK-1 K+ channel (p.L114P) is associated with maturity-onset diabetes of the young (MODY). TALK-1 is a key regulator of β-cell electrical activity and glucose-stimulated insulin secretion. The KCNK16 gene encoding TALK-1 is the most abundant and β-cell-restricted K+ channel transcript. To investigate the impact of KCNK16 L114P on glucose homeostasis and confirm its association with MODY, a mouse model containing the Kcnk16 L114P mutation was generated. Heterozygous and homozygous Kcnk16 L114P mice exhibit increased neonatal lethality in the C57BL/6J and the CD-1 (ICR) genetic background, respectively. Lethality is likely a result of severe hyperglycemia observed in the homozygous Kcnk16 L114P neonates due to lack of glucose-stimulated insulin secretion and can be reduced with insulin treatment. Kcnk16 L114P increased whole-cell β-cell K+ currents resulting in blunted glucose-stimulated Ca2+ entry and loss of glucose-induced Ca2+ oscillations. Thus, adult Kcnk16 L114P mice have reduced glucose-stimulated insulin secretion and plasma insulin levels, which significantly impairs glucose homeostasis. Taken together, this study shows that the MODY-associated Kcnk16 L114P mutation disrupts glucose homeostasis in adult mice resembling a MODY phenotype and causes neonatal lethality by inhibiting islet insulin secretion during development. These data suggest that TALK-1 is an islet-restricted target for the treatment for diabetes.
-
- Developmental Biology
- Structural Biology and Molecular Biophysics
A crucial event in sexual reproduction is when haploid sperm and egg fuse to form a new diploid organism at fertilization. In mammals, direct interaction between egg JUNO and sperm IZUMO1 mediates gamete membrane adhesion, yet their role in fusion remains enigmatic. We used AlphaFold to predict the structure of other extracellular proteins essential for fertilization to determine if they could form a complex that may mediate fusion. We first identified TMEM81, whose gene is expressed by mouse and human spermatids, as a protein having structural homologies with both IZUMO1 and another sperm molecule essential for gamete fusion, SPACA6. Using a set of proteins known to be important for fertilization and TMEM81, we then systematically searched for predicted binary interactions using an unguided approach and identified a pentameric complex involving sperm IZUMO1, SPACA6, TMEM81 and egg JUNO, CD9. This complex is structurally consistent with both the expected topology on opposing gamete membranes and the location of predicted N-glycans not modeled by AlphaFold-Multimer, suggesting that its components could organize into a synapse-like assembly at the point of fusion. Finally, the structural modeling approach described here could be more generally useful to gain insights into transient protein complexes difficult to detect experimentally.
