Related Experiment Video
Updated: Jan 18, 2026
In vitro Quantitative Imaging Assay for Phagocytosis of Dead Neuroblastoma Cells by iPSC-Macrophages
Published on: February 14, 2021
CD300f enables microglial damage sensing, efferocytosis, and apoptotic cell metabolization after brain injury
Luciana Negro-Demontel1, Frances Evans2, Andrés Cawen3
1Department of Histology and Embriology, School of Medicine, UDELAR, Montevideo, 11800, Uruguay; Institut Pasteur de Montevideo, Montevideo, 11400, Uruguay; National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
Abstract:
Microglia, the resident phagocytes of the central nervous system (CNS), continuously survey the parenchyma and its borders, acting as first responders to brain injury. Their ability to detect and react to environmental changes is mediated by a repertoire of surface receptors collectively known as themicroglial sensome. Here, we identify the lipid-sensing immunoreceptor CD300f as a key regulator of microglial responses to tissue damage and apoptotic cells. Using intravital two-photon microscopy, we show that CD300f-/- microglia fail to extend processes toward a laser-induced cortical lesion, indicating impaired detection of damage-associated cues. In models of mild traumatic brain injury (mTBI) and intracortical injection of apoptotic cells, CD300f deficiency led to reduced recognition and clearance of dying cells resulting in the accumulation of cellular debris within the parenchyma. At later stages, apoptotic remnants were retained within CD300f-/- microglia in vivo and bone marrow-derived macrophages in vitro, suggesting defective intracellular degradation. Proteomic analysis after a controlled cortical injury (CCI) contusion model revealed widespread dysregulation of autophagy-related and metabolic pathways, consistent with impaired efferocytosis and phagolysosomal processing. In parallel, we observed upregulation of the UDP-degrading ectonucleotidase ENTPD6 protein and downregulation of the microglial purinergic receptor P2ry6 mRNA, indicating a dysfunctional UDP-P2RY6 axis that may underlie impaired damage sensing and phagocytic initiation. Despite greater histological preservation, CD300f-/- mice exhibited worse long-term functional recovery after brain injury. Together, these findings highlight CD300f as a key damage-associated molecular pattern (DAMP) receptor that integrates purinergic signaling, efferocytosis, and metabolic adaptation, highlighting its essential role in coordinating microglial responses to CNS injury.
Insights
The lipid-sensing receptor CD300f is crucial for microglia to detect brain injury and clear cellular debris. Its absence impairs microglial function, leading to worse long-term recovery after central nervous system (CNS) injury.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Microglia are the primary immune cells in the central nervous system (CNS), responsible for detecting and responding to injury.
- The microglial sensome, a collection of surface receptors, mediates their ability to sense environmental changes.
- CD300f is identified as a lipid-sensing immunoreceptor involved in microglial responses.
Purpose of the Study:
- To investigate the role of the lipid-sensing immunoreceptor CD300f in microglial responses to CNS injury.
- To determine how CD300f deficiency affects the detection, clearance, and degradation of apoptotic cells and debris.
- To elucidate the impact of CD300f on long-term functional recovery after brain injury.
Main Methods:
- Intravital two-photon microscopy to observe microglial process extension toward laser-induced lesions.
- Modeling mild traumatic brain injury (mTBI) and intracortical injection of apoptotic cells in CD300f knockout mice.
- Proteomic analysis of microglial responses following controlled cortical injury (CCI).
- In vivo and in vitro assessment of efferocytosis and intracellular degradation.
Main Results:
- CD300f deficiency impairs microglial process extension towards injury sites and reduces clearance of apoptotic cells.
- Absence of CD300f leads to accumulation of cellular debris and defective intracellular degradation of apoptotic remnants.
- Dysregulation of autophagy and metabolic pathways, along with a dysfunctional UDP-P2RY6 axis, was observed in CD300f-deficient microglia.
- CD300f knockout mice showed worse long-term functional recovery despite better initial histological preservation.
Conclusions:
- CD300f is a critical receptor for damage-associated molecular patterns (DAMPs) in the CNS.
- CD300f integrates purinergic signaling, efferocytosis, and metabolic adaptation for effective microglial response to injury.
- Targeting CD300f may offer therapeutic potential for improving outcomes after CNS injury.
