Related Experiment Video
Updated: May 8, 2026
Highly Efficient Transfection of Human THP-1 Macrophages by Nucleofection
Published on: September 2, 2014
IL-4 reduces the proangiogenic capacity of macrophages by down-regulating HIF-1α translation
Nathalie Dehne1, Michaela Tausendschön, Silke Essler
11.Goethe-University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany. dehne@biochem.uni-frankfurt.de.
Abstract:
MΦ show a highly versatile phenotype depending on the receiving microenvironmental stimuli. MΦ phenotypes are grouped in three subcategories. One is classically activated MΦ (after stimulation with LPS or IFN-γ), and two are alternatively activated forms, known as wound-healing MΦ (induced by IL-4/IL-13) and regulatory MΦ (induced by IL-10/TGF-β). Besides cytokines, hypoxia defines MΦ functions, as shown for classically activated cells. Yet, little is known about the role of hypoxia and HIF-1 and -2 in wound-healing or regulatory MΦ. HIF target genes (such as ADM), analyzed in alternatively activated MΦ from WT and HIF-/- mice, were regulated predominantly by HIF-1 and consistently showed reduced hypoxic induction in MΦ stimulated with IL-4. To gain mechanistic insights, we analyzed HIF expression in polarized MΦ. Classically activated MΦ are characterized by the induction of HIF-1α but reduction of HIF-2α mRNA and protein, whereas wound-healing MΦ decreased HIF-1α protein expression without altering mRNA levels. Analysis of protein stability and expression after proteasomal inhibition pointed to translational regulation of HIF-1α in wound-healing MΦ. Following angiogenic-sprouting using embryonic stem cells exposed to supernatants of MΦ incubated with IL-4 under hypoxia, shorter sprouts were revealed compared with supernatants of hypoxic MΦ without IL-4. Conclusively, IL-4 reduces HIF-1α translation and thus, its activity in MΦ and concomitantly, attenuates their ability to promote angiogenesis under hypoxic conditions.
Insights
Interleukin-4 (IL-4) reduces hypoxia-inducible factor-1 alpha (HIF-1α) translation in macrophages, thereby decreasing their ability to promote angiogenesis in hypoxic environments.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Macrophage (MΦ) phenotypes are versatile, influenced by microenvironmental cues like cytokines and hypoxia.
- While hypoxia's role in classically activated MΦ is known, its impact on wound-healing and regulatory MΦ remains unclear.
- Hypoxia-inducible factors (HIFs) are crucial regulators of cellular response to hypoxia.
Purpose of the Study:
- To investigate the role of hypoxia and HIF-1/-2 in alternatively activated macrophages (wound-healing and regulatory MΦ).
- To elucidate the mechanistic regulation of HIFs in different MΦ polarization states.
- To determine the functional consequences of IL-4-mediated HIF regulation on angiogenesis.
Main Methods:
- Analysis of HIF target gene expression (e.g., ADM) in alternatively activated MΦ from wild-type and HIF knockout mice.
- Examination of HIF-1α and HIF-2α mRNA and protein expression in classically activated and wound-healing MΦ.
- Assessment of HIF-1α protein stability and translational regulation via proteasomal inhibition.
- In vitro angiogenesis assays using embryonic stem cells exposed to MΦ supernatants under hypoxic conditions.
Main Results:
- HIF-1 predominantly regulated HIF target genes in alternatively activated MΦ, with reduced hypoxic induction observed with IL-4 stimulation.
- Classically activated MΦ showed induced HIF-1α but reduced HIF-2α, while wound-healing MΦ exhibited decreased HIF-1α protein without altered mRNA levels.
- Proteasomal inhibition suggested translational regulation of HIF-1α in wound-healing MΦ.
- Supernatants from IL-4-treated hypoxic MΦ resulted in shorter angiogenic sprouts compared to controls.
Conclusions:
- IL-4 significantly reduces HIF-1α translation and activity in macrophages.
- This IL-4-mediated suppression of HIF-1α attenuates the pro-angiogenic capacity of macrophages under hypoxic conditions.
- Findings reveal a novel mechanism by which IL-4 modulates macrophage function and angiogenesis in response to hypoxia.
More Related Videos
07:44Studying the Effects of Tumor-Secreted Paracrine Ligands on Macrophage Activation using Co-Culture with Permeable Membrane Supports
Published on: November 28, 2019
10:35Assessment of Antibody-based Drugs Effects on Murine Bone Marrow and Peritoneal Macrophage Activation
Published on: December 26, 2017
Related Concept Videos
01:24Regulation of Angiogenesis and Blood Supply
01:16TGF - β Signaling Pathway
01:20The JAK-STAT Signaling Pathway
01:24T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...