Activated Macrophages Promote TNF-α-Associated Tumor Cell Necroptosis in Pituitary Apoplexy Through the PIEZO1–NFATC2/REL Axis

Pituitary apoplexy is an uncommon but clinically urgent complication that often involves intrasellar hemorrhage and tissue necrosis. The mechanisms linking acute tissue injury to the inflammatory tumor microenvironment remain incompletely defined. Here, we characterized the apoplexy-associated microenvironment and examined whether macrophage mechanosensitive signaling contributes to inflammatory amplification and tissue damage in pituitary neuroendocrine tumors (PitNETs). We combined single-cell RNA sequencing (scRNA-seq), histological validation, clinical stratification, and in vitro functional assays using apoplectic and non-apoplectic human PitNET specimens. Macrophage state transitions, intercellular communication, and transcriptional regulatory programs were analyzed, followed by an experimental assessment of the PIEZO1–Ca2+ axis and macrophage-conditioned medium-induced tumor cell death. Histological validation confirmed macrophage accumulation in apoplectic PitNETs, including a 1.67-fold increase in IBA-1-positive cells (p < 0.001). CellChat-inferred interaction metrics increased descriptively in apoplectic samples. Apoplectic tissues showed higher TNF-α expression (3.00-fold; p < 0.0001) and higher PIEZO1 fluorescence in IBA-1-positive regions (1.39-fold; p = 0.001). Yoda1 increased Calcium 520 fluorescence in macrophages (1.72-fold; p = 0.002), whereas Piezo1 knockdown reduced the Yoda1-associated response (p = 0.003). Conditioned medium from activated macrophages increased total Annexin V/PI-positive death in AtT-20 cells (0.53 ± 0.53% to 32.48 ± 1.14%; p < 0.001) and GH3 cells (0.82 ± 0.50% to 30.92 ± 1.11%; p < 0.001); Piezo1 knockdown or TNF-α neutralization attenuated this effect. Clinically, pathological necrosis was associated with higher symptom frequencies and a greater adjusted likelihood of two or more clinical symptoms. Together, these findings indicate that PIEZO1-related macrophage signaling may participate in TNF-α-associated tumor cell necroptosis in pituitary apoplexy. Pathological necrosis was linked to greater acute symptom burden and perioperative hormonal abnormalities, suggesting that it may identify a clinically severe apoplexy subtype.