Disease Associated Microglia Type 2 (Dam2) is a cell type relevant to neurodegenerative disease research. This page covers its role in brain function, involvement in disease processes, and significance for therapeutic strategies.
Disease-Associated Microglia Type 2 (DAM2) represents an intermediate activation state within the disease-associated microglia (DAM) continuum. DAM2 microglia are characterized by a unique transcriptional profile that bridges the transition from homeostatic microglia (DAM0/DAM1) to the fully activated DAM phenotype. This state was identified through single-cell RNA sequencing studies of Alzheimer's disease mouse models and is now recognized as a critical stage in microglial activation during neurodegeneration [1].
The DAM2 stage represents a transitional state where microglia have:
DAM2 microglia express a distinct gene signature:
| Gene | Expression | Function |
|---|---|---|
| APOE | High | Lipid transport, lipidated ApoE production |
| TYROBP (DAP12) | High | Signaling adaptor, ITAM pathway |
| CST7 (Cystatin F) | High | Lysosomal cysteine protease inhibitor |
| ITGAX (CD11c) | High | Integrin, cell adhesion |
| CLECL1 | Moderate | C-type lectin receptor |
| LPL | High | Lipoprotein lipase, lipid metabolism |
| CD9 | High | Tetraspanin, membrane organization |
The progression to DAM2 follows a staged pathway:
Homeostatic (DAM0/1) → DAM1 → DAM2 → DAM1-like/DAM
↓ ↓ ↓ ↓
P2RY12+ Apoe+ Itgax+ Itgax+/-
Cx3cr1+ Tyrobp+ Cst7+ Cst7+/-
Tmem119+ Lpl+ Lpl++ Lpl+++
TREM2-dependent (typical DAM):
TREM2-independent (alternative DAM):
DAM2 microglia exhibit enhanced phagocytic capacity:
DAM2 represents a lipid-handling state:
DAM2 microglia upregulate antigen presentation machinery:
DAM2 microglia are prominently found surrounding amyloid plaques:
In tauopathy models:
The role of DAM2 remains controversial:
Neuroprotective aspects:
Pathogenic aspects:
| Strategy | Approach | Status |
|---|---|---|
| TREM2 agonism | Activate TREM2 signaling | Clinical trials (AL002, AL003) |
| CSF1R inhibition | Reduce microglial proliferation | Preclinical |
| Lipid metabolism modulation | Target LPL, APOE pathways | Investigational |
| CD11c targeting | Modulate Itgax+ cells | Preclinical |
DAM2-associated proteins as disease biomarkers:
The study of Disease Associated Microglia Type 2 (Dam2) has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
Keren-Shaul H, Spinrad A, Weiner A, et al. A Unique Microglia Type Associated with Restricting Development of Alzheimer's Disease. Cell. 2017;169(7):1276-1290.e17. PMID:27211357.
Deczkowska A, Keren-Shaul H, Weiner A, et al. Disease-Associated Microglia: A Universal Immune Sensor of Neurodegeneration. Cell. 2018;173(5):1073-1081. PMID:29775591.
Gratuze M, Leyns CE, Holtzman DM. New insights into the role of TREM2 in Alzheimer's disease. Mol Neurodegener. 2018;13(1):66. PMID:30563541.
Ulland TK, Colonna M. TREM2 - a key player in microglial biology and Alzheimer disease. Nat Rev Neurol. 2018;14(11):667-675. PMID:30297807.
Krasemann S, Madore C, Cialic R, et al. The TREM2-APOE Pathway Drives the Transcriptional Phenotype of Dysfunctional Microglia in Neurodegenerative Diseases. Immunity. 2017;47(3):566-581.e9. PMID:28930663.
Guo Y, Wei X, Yan H, et al. DAM in Alzheimer's disease: the role of microglial phenotypes. J Neuroinflammation. 2022;19(1):195. PMID:35850744.
Wang S, Sudan R, Peng V, et al. TREM2 drives microglia response to amyloid-β via SYK-dependent and -independent pathways. J Exp Med. 2022;219(12):e20212491. PMID:36129502.
Zhou Y, Song WM, Andhey PS, et al. Human and mouse single-nucleus transcriptomics reveal TREM2-dependent and TREM2-independent cellular states in Alzheimer's disease. Cell. 2020;183(7):1801-1817.e26. PMID:33268867.