Triggering receptor expressed on myeloid cells 2-driven pancreatic macrophage crosstalk: Key regulator of obesity pathophysiology and metabolic dysregulation

Obesity, a global epidemic, is closely linked to metabolic complications like insulin resistance and type 2 diabetes. Pancreatic dysfunction (impaired islet secretion and local inflammation) is central to this deterioration, yet the underlying mechanisms remain unclear. Pancreatic macrophages regulate tissue inflammation and metabolic homeostasis, but their context-specific polarization in obesity is undefined. This review discusses the role of triggering receptor expressed on myeloid cells 2 (TREM2) in modulating pancreatic macrophage behavior in the context of obesity, based on findings from diet-induced obese mouse models and ex vivo pancreatic analyses. Emerging evidence indicates that TREM2 expression is markedly upregulated in pancreatic macrophages of obese subjects, where TREM2-driven macrophage activation promotes pro-inflammatory cytokine release and disrupts macrophage-islet β-cell crosstalk. Transcriptomic profiling reveals that TREM2 signaling reshapes macrophage transcriptional landscapes, enhancing pro-inflammatory phenotypes while impairing islet-supporting capacity. Notably, macrophage-specific TREM2 ablation has been shown to ameliorate pancreatic inflammation, restore islet insulin secretion, and alleviate systemic metabolic disorders in obese mice. Collectively, these findings identify TREM2 as a pivotal molecular switch governing pancreatic macrophage-mediated metabolic dysfunction in obesity, highlighting TREM2+ pancreatic macrophages as a potential therapeutic target. These findings advance the understanding of immune-metabolic crosstalk in the pancreas, laying a foundation for developing novel immunometabolic interventions.