CD300A Gene
Overview
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CD300A Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>CD300A</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>CD300A</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=CD300A" target="_blank">Search NCBI</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
CD300A encodes an inhibitory immunoreceptor (CD300a, IRp60) expressed mainly in myeloid and lymphoid compartments, including [microglia](/cell-types/microglia).[@cantoni1999][@borrego2013] Its intracellular ITIM motifs recruit phosphatase pathways that dampen activation signaling, making CD300A a checkpoint for inflammatory tone rather than a primary neurodegeneration gene.[@cantoni1999][@nakahashioda2012]
In neurodegenerative disease, CD300A is best framed as an immune-state modulator at the interface of apoptotic-cell sensing, phagocytic restraint, and cytokine calibration. These functions are mechanistically relevant to [neuroinflammation](/mechanisms/neuroinflammation), [Alzheimer's disease](/diseases/alzheimers-disease), and [Parkinson's disease](/diseases/parkinsons-disease), where myeloid response programs can shift from protective to maladaptive states.[@borrego2013][@heneka2018]
Gene And Receptor Biology
...CD300A Gene
Overview
<table class="infobox infobox-gene">
<tr>
<th class="infobox-header" colspan="2">CD300A Gene</th>
</tr>
<tr>
<td class="label">Symbol</td>
<td><strong>CD300A</strong></td>
</tr>
<tr>
<td class="label">Full Name</td>
<td>CD300A</td>
</tr>
<tr>
<td class="label">Type</td>
<td>Gene</td>
</tr>
<tr>
<td class="label">NCBI</td>
<td><a href="https://www.ncbi.nlm.nih.gov/gene/?term=CD300A" target="_blank">Search NCBI</a></td>
</tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
CD300A encodes an inhibitory immunoreceptor (CD300a, IRp60) expressed mainly in myeloid and lymphoid compartments, including [microglia](/cell-types/microglia).[@cantoni1999][@borrego2013] Its intracellular ITIM motifs recruit phosphatase pathways that dampen activation signaling, making CD300A a checkpoint for inflammatory tone rather than a primary neurodegeneration gene.[@cantoni1999][@nakahashioda2012]
In neurodegenerative disease, CD300A is best framed as an immune-state modulator at the interface of apoptotic-cell sensing, phagocytic restraint, and cytokine calibration. These functions are mechanistically relevant to [neuroinflammation](/mechanisms/neuroinflammation), [Alzheimer's disease](/diseases/alzheimers-disease), and [Parkinson's disease](/diseases/parkinsons-disease), where myeloid response programs can shift from protective to maladaptive states.[@borrego2013][@heneka2018]
Gene And Receptor Biology
CD300A is a member of the CD300 immunoglobulin receptor family on chromosome 17q25.1.[@cantoni1999] The receptor architecture contains:
- an extracellular Ig-like domain that recognizes lipid ligands;
- a transmembrane segment;
- a cytoplasmic tail with ITIM sequences that engage SHP phosphatases after receptor phosphorylation.[@cantoni1999][@nakahashioda2012]
A central biology of CD300A is binding to phosphatidylserine and phosphatidylethanolamine exposed on stressed or apoptotic membranes. This interaction restrains immune-cell activation and shapes efferocytic responses.[@nakahashioda2012][@simhadri2012]
Cellular And Systems Function
Innate immune regulation
CD300A attenuates activation cascades in monocytes/macrophages, dendritic cells, mast cells, and NK cells, reducing inflammatory mediator release when inhibitory signaling dominates.[@cantoni1999][@borrego2013]
Microglial relevance
In CNS contexts, inhibitory receptors such as CD300A can alter microglial thresholding for phagocytosis, cytokine production, and synapse-associated remodeling.[@borrego2013][@heneka2018] This is especially relevant in diseases with chronic debris burden and damaged neurites.
Interaction with disease-risk immune networks
Although [TREM2](/proteins/trem2) and TYROBP pathways are typically discussed as pro-phagocytic signaling modules, CD300A represents the complementary inhibitory side of the immune-control axis. Balance between activating and inhibitory receptors likely determines whether glial responses remain adaptive.[@heneka2018][@kerenshaul2017]
Disease-Relevant Evidence
Alzheimer's disease
AD neuropathology includes persistent microglial activation around plaques, with immunoreceptor programs strongly remodeled in transcriptomic datasets.[@heneka2018][@kerenshaul2017] CD300A is not a top monogenic AD driver, but inhibitory receptor signaling is increasingly recognized as a determinant of inflammatory set point and phagocytic efficiency.
Potential implications include:
- tuning uptake of apoptotic membranes and neuritic debris;
- modulating IL-1/TNF-associated inflammatory amplification;
- shaping transition between homeostatic and disease-associated microglial states.[@borrego2013][@heneka2018][@kerenshaul2017]
Parkinson's disease and synuclein pathology
In PD and related synucleinopathies, activated myeloid cells participate in neurotoxic and reparative loops. Inhibitory immunoreceptors can modulate these loops, suggesting CD300A as a potential context-dependent modifier of disease tempo.[@borrego2013][@tansey2018]
Autoimmune and peripheral neuroimmune context
Outside classic neurodegeneration, CD300A associations in immune-mediated disorders support its role as a broad inflammation rheostat.[@cantoni1999][@zenarruzabeitia2015] This strengthens biological plausibility for CNS relevance via peripheral-immune and CNS-myeloid crosstalk.
Translational Implications
CD300A is currently a pathway-level target rather than a near-term monotherapy target in neurodegeneration. Practical translational directions include:
- multi-marker profiling of inhibitory and activating myeloid receptors;
- stratifying inflammatory phenotypes for trial enrichment;
- testing combinatorial approaches pairing anti-aggregate or anti-[tau](/proteins/tau) therapies with immune-state modulators.[@heneka2018][@kerenshaul2017]
Key caution: excessive inhibitory signaling could blunt beneficial clearance responses, while insufficient inhibitory signaling could worsen bystander injury. Therapeutic direction may therefore depend on disease stage and biomarker-defined immune state.[@borrego2013][@heneka2018]
Open Questions
- Which CD300A-positive CNS/perivascular cell subsets are most relevant in human AD/PD tissue?
- How does CD300A signaling integrate with [complement-mediated synaptic pruning](/mechanisms/complement-mediated-synaptic-pruning) and TREM2 programs?
- Can soluble lipid-ligand signatures predict when inhibitory checkpoint reinforcement is beneficial versus harmful?
Resolving these questions will require single-cell spatial profiling, ligand-occupancy assays, and longitudinal biofluid-immune panels in deeply phenotyped cohorts.[@heneka2018][@kerenshaul2017][@tansey2018]
See Also
- [neuroinflammation](/mechanisms/neuroinflammation)
- [Alzheimer's disease](/diseases/alzheimers-disease)
- [Parkinson's disease](/diseases/parkinsons-disease)
- [complement-mediated synaptic pruning](/mechanisms/complement-mediated-synaptic-pruning)
External Links
- [PubMed](https://pubmed.ncbi.nlm.nih.gov/)
- [KEGG Pathways](https://www.genome.jp/kegg/pathway.html)
References
[Cantoni C, Bottino C, Augugliaro R, et al, Molecular and functional characterization of IRp60, a member of the immunoglobulin superfamily that functions as an inhibitory receptor in human NK cells (1999)](https://doi.org/10.1074/jbc.274.33.23088)
[Borrego F, The CD300 molecules: an emerging family of regulators of the immune system (2013)](https://doi.org/10.1016/j.it.2013.01.003)
[Nakahashi-Oda C, Tahara-Hanaoka S, Totsuka N, et al, Apoptotic cells suppress mast cell inflammatory responses via the CD300a immunoreceptor (2012)](https://doi.org/10.1084/jem.20120096)
[Heneka MT, McManus RM, Latz E, Inflammasome signalling in brain function and neurodegenerative disease (2018)](https://doi.org/10.1038/s41583-018-0055-7)
[Simhadri VR, Andersen JF, Calvo E, et al, Human CD300a binds to phosphatidylethanolamine and phosphatidylserine, and modulates phagocytosis (2012)](https://pubmed.ncbi.nlm.nih.gov/22474022/)
[Keren-Shaul H, Spinrad A, Weiner A, et al, A unique microglia type associated with restricting development of Alzheimer's disease (2017)](https://doi.org/10.1016/j.cell.2017.05.018)
[Tansey MG, Romero-Ramos M, Immune system responses in Parkinson's disease: early and dynamic (2018)](https://doi.org/10.1016/j.tins.2018.10.007)
[Zenarruzabeitia O, Vitallé J, Eguizabal C, Simhadri VR, Borrego F, The biology and disease relevance of CD300 receptors (2015)](https://doi.org/10.3389/fimmu.2015.00290)