The complex TIE between macrophages and angiogenesis
Charis Du Cheyne1, Hanna Tay1, Ward De Spiegelaere1
1Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
Abstract:
Macrophages are primarily known as phagocytic immune cells, but they also play a role in diverse processes, such as morphogenesis, homeostasis and regeneration. In this review, we discuss the influence of macrophages on angiogenesis, the process of new blood vessel formation from the pre-existing vasculature. Macrophages play crucial roles at each step of the angiogenic cascade, starting from new blood vessel sprouting to the remodelling of the vascular plexus and vessel maturation. Macrophages form promising targets for both pro- and anti-angiogenic treatments. However, to target macrophages, we will first need to understand the mechanisms that control the functional plasticity of macrophages during each of the steps of the angiogenic cascade. Here, we review recent insights in this topic. Special attention will be given to the TIE2-expressing macrophage (TEM), which is a subtype of highly angiogenic macrophages that is able to influence angiogenesis via the angiopoietin-TIE pathway.
Insights
Macrophages are key immune cells influencing blood vessel formation (angiogenesis) throughout its stages. Understanding their plasticity, especially TIE2-expressing macrophages, is crucial for developing new pro- or anti-angiogenic therapies.
Area of Science:
- Immunology
- Vascular Biology
- Cell Biology
Background:
- Macrophages are immune cells with diverse functions beyond phagocytosis, including roles in tissue development and repair.
- Angiogenesis, the formation of new blood vessels, is a complex process vital for development, wound healing, and disease.
- Macrophages are increasingly recognized for their significant contributions to various stages of angiogenesis.
Purpose of the Study:
- To review the multifaceted roles of macrophages in the angiogenic cascade.
- To highlight the importance of understanding macrophage functional plasticity in angiogenesis.
- To discuss TIE2-expressing macrophages (TEMs) as key players in promoting angiogenesis.
Main Methods:
- Literature review of recent research on macrophages and angiogenesis.
- Analysis of the mechanisms controlling macrophage plasticity during angiogenesis.
- Focus on the angiopoietin-TIE pathway involving TEMs.
Main Results:
- Macrophages influence every step of angiogenesis, from sprouting to vessel maturation.
- Macrophage plasticity is critical for regulating angiogenic processes.
- TIE2-expressing macrophages (TEMs) are a specific subtype that significantly promotes angiogenesis via the angiopoietin-TIE pathway.
Conclusions:
- Macrophages are essential regulators of angiogenesis and represent promising therapeutic targets.
- Targeting macrophages for pro- or anti-angiogenic treatments requires a deep understanding of their dynamic functions.
- Further research into TEMs and their signaling pathways can unlock new therapeutic strategies for angiogenesis-related conditions.
Related Concept Videos
01:24Regulation of Angiogenesis and Blood Supply
01:10Mechanism of Angiogenesis
02:17The Tumor Microenvironment
01:24Overview of Cell-Matrix Interactions