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EMBO J. 2016 Jan 4;35(1):102-13. doi: 10.15252/embj.201592775. Epub 2015 Nov 23.

A novel family of fluorescent hypoxia sensors reveal strong heterogeneity in tumor hypoxia at the cellular level.

Author information

1
Mammalian Cell Signaling Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany Cluster of Excellence EXC 1003, Cells in Motion CiM, Münster, Germany.
2
Institute of Bioorganic Chemistry, Moscow, Russia.
3
Cluster of Excellence EXC 1003, Cells in Motion CiM, Münster, Germany European Institute for Molecular Imaging - EIMI, Münster, Germany.
4
Mammalian Cell Signaling Laboratory, Max Planck Institute for Molecular Biomedicine, Münster, Germany Cluster of Excellence EXC 1003, Cells in Motion CiM, Münster, Germany fkiefer@gwdg.de.

Abstract

Hypoxia is an intensively investigated condition with profound effects on cell metabolism, migration, and angiogenesis during development and disease. Physiologically, hypoxia is linked to tissue homeostasis and maintenance of pluripotency. Hypoxia also contributes to pathologies including cardiovascular diseases and cancer. Despite its importance, microscopic visualization of hypoxia is largely restricted to the detection of reductively activated probes by immunostaining. Here, we describe a novel family of genetically encoded fluorescent sensors that detect the activation of HIF transcription factors reported by the oxygen-independent fluorescent protein UnaG. It comprises sensors with different switching and memory behavior and combination sensors that allow the distinction of hypoxic and reoxygenated cells. We tested these sensors on orthotopically transplanted glioma cell lines. Using a cranial window, we could visualize hypoxia intravitally at cellular resolution. In tissue samples, sensor activity was detected in regions, which were largely devoid of blood vessels, correlated with HIF-1α stabilization, and were highly heterogeneous at a cellular level. Frequently, we detected recently reoxygenated cells outside hypoxic areas in the proximity of blood vessels, suggestive of hypoxia-promoted cell migration.

KEYWORDS:

UnaG; fluorescent protein; hypoxia; microscopy; sensor

PMID:
26598532
PMCID:
PMC4718004
DOI:
10.15252/embj.201592775
[Indexed for MEDLINE]
Free PMC Article

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