Human Microglia-like Cells: Differentiation from Induced Pluripotent Stem Cells and In Vitro Live-cell Phagocytosis
1Department of Neurology, University of Massachusetts Chan Medical School; Translation Science Program, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School.
Abstract:
Microglia are the resident immune cells of myeloid origin that maintain homeostasis in the brain microenvironment and have become a key player in multiple neurological diseases. Studying human microglia in health and disease represents a challenge due to the extremely limited supply of human cells. Induced pluripotent stem cells (iPSCs) derived from human individuals can be used to circumvent this barrier. Here, it is demonstrated how to differentiate human iPSCs into microglia-like cells (iMGs) for in vitro experimentation. These iMGs exhibit the expected and physiological properties of microglia, including microglia-like morphology, expression of proper markers, and active phagocytosis. Additionally, documentation for isolating and labeling synaptosome substrates derived from human iPSC-derived lower motor neurons (i3LMNs) is provided. A live-cell, longitudinal imaging assay is used to monitor engulfment of human synaptosomes labeled with a pH-sensitive dye, allowing for investigations of iMG's phagocytic capacity. The protocols described herein are broadly applicable to different fields that are investigating human microglia biology and the contribution of microglia to disease.
Insights
Researchers developed a method to create human microglia-like cells (iMGs) from induced pluripotent stem cells (iPSCs). These iMGs accurately model human microglia for studying neurological diseases.
Area of Science:
- Neuroscience
- Immunology
- Stem Cell Biology
Background:
- Microglia are crucial for brain homeostasis and implicated in neurological diseases.
- Obtaining sufficient human microglia for research is challenging.
- Induced pluripotent stem cells (iPSCs) offer a viable alternative for generating human cell models.
Purpose of the Study:
- To establish a protocol for differentiating human iPSCs into microglia-like cells (iMGs).
- To characterize the physiological properties of these iMGs.
- To develop an assay for assessing iMG phagocytic capacity using human synaptosomes.
Main Methods:
- Differentiation of human iPSCs into iMGs.
- Characterization of iMGs for morphology, marker expression, and phagocytosis.
- Isolation and labeling of synaptosomes from human iPSC-derived lower motor neurons (i3LMNs).
- Live-cell imaging assay to monitor synaptosome engulfment by iMGs.
Main Results:
- Successfully differentiated iPSCs into iMGs with microglia-like characteristics.
- Confirmed iMGs express appropriate markers and exhibit active phagocytosis.
- Demonstrated a functional assay to quantify iMG phagocytic activity towards human synaptosomes.
Conclusions:
- Human iPSC-derived microglia (iMGs) provide a valuable in vitro model for studying human microglia biology.
- The developed protocols enable research into microglia's role in neurological health and disease.
- This approach overcomes limitations associated with the scarcity of primary human microglia.
