Related Experiment Videos
Hypoxia affects mesoderm and enhances hemangioblast specification during early development
Diana L Ramírez-Bergeron1, Anja Runge, Karen D Cowden Dahl
1Howard Hughes Medical Institute and Abramson Family Cancer Research Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
Development (Cambridge, England)
|September 3, 2004
Summary
Hypoxia Inducible Factor (HIF) is crucial for blood and vessel development. Hypoxia accelerates hemangioblast differentiation via HIF, with defects in Arnt(-/-) cells highlighting HIF
Area of Science:
- Developmental Biology
- Cell Biology
- Molecular Biology
Background:
- Hypoxia Inducible Factor (HIF), comprising HIF1alpha and ARNT (HIF1beta) subunits, regulates gene expression in response to oxygen deprivation.
- Arnt-deficient (Arnt-/-) mice display significant impairments in blood cell and vessel formation.
- Embryonic stem (ES) cells are a valuable model for studying early developmental processes.
Purpose of the Study:
- To investigate the role of hypoxia and HIF signaling in the differentiation of embryonic hemangioblasts.
- To determine the impact of ARNT deficiency on mesoderm and hemangioblast development.
- To identify HIF-dependent factors regulating early cardiovascular progenitor cell formation.
Main Methods:
- Utilized differentiating mouse embryonic stem (ES) cell cultures under varying oxygen conditions.
- Assessed the expression of key developmental genes including Brachyury, BMP4, and FLK1.
- Quantified hemangioblast progenitor cell (BL-CFC) proliferation and differentiation.
- Employed Arnt(+/+) and Arnt(-/-) ES cells, as well as Vegf(+/-) and Vegf(-/-) ES cells.
Main Results:
- Hypoxia accelerated the expression of Brachyury, BMP4, and FLK1 in differentiating ES cells.
- Embryonic hemangioblast proliferation (BL-CFCs) was enhanced by hypoxia in an HIF-dependent manner.
- Arnt(-/-) ES cells showed reduced FLK1(+) cells and BL-CFCs under both normoxic and hypoxic conditions.
- Co-culturing Arnt(-/-) ES cells with Arnt(+/+) ES cells rescued the differentiation defect.
- VEGF-independent HIF-regulated pathways are also involved in hemangioblast differentiation.
Conclusions:
- Hypoxic responses are essential for establishing progenitor cells, including early mesoderm and hemangioblasts.
- ARNT-mediated HIF signaling is critical for proper cardiovascular development during embryogenesis.
- Ineffective hypoxic responses in Arnt(-/-) embryos disrupt hemangioblast differentiation pathways, leading to developmental defects.