The Role of TREM2 After Stroke: From Mechanisms to Therapeutic Potential.

Stroke, including cerebral ischemia and cerebral hemorrhage, is one of the leading causes of mortality worldwide. The narrow therapeutic window limits the efficacy and applicability of current treatments such as thrombolysis and endovascular thrombectomy. This urgent need for effective therapies has shifted the focus towards mitigating the secondary inflammation and tissue damage that follow intracerebral hemorrhage. Spatial transcriptomic analysis of mouse brains post-ischemia has revealed that the ApoE-TREM2 signaling pathway is central to the complex interactions between microglia and various surrounding cells, coordinating the formation of neuroglial scars, suggesting that TREM2 is a key participant in post-stroke pathology and a potential therapeutic target. This review aims to provide an insightful synthesis of TREM2, including its structure, signaling pathways, and the role of its soluble form, sTREM2, in the nervous system. We systematically summarize the signaling pathways and mechanisms by which TREM2 modulates microglial function, including promoting phagocytosis, exerting anti-inflammatory properties, modulating lipid metabolism, and enhancing cell survival. We also highlight the TREM2's interactions with other cell types post-stroke, such as macrophages and B cells. Furthermore, we discuss advancements in TREM2-targeted drug development, emphasizing the potential of TREM2 agonists and antibodies to modulate microglial function and inflammation, which sets the stage for future research and drug development.