P2X7-CaMKII drives 5-LOX nuclear translocation to impair microglial function after subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a common acute condition in neurosurgery, with microglial function playing a crucial role in determining patient outcomes. However, the involved mechanisms are complex and demand thorough investigation. In our study, we combined transcriptomic and metabolomic approaches to identify key regulators of microglial function, offering novel insights for potential therapeutic strategies in SAH treatment. The neurological function of SAH mice was evaluated using the open field test, rotarod test, and nissl staining. In an in vitro SAH model, key pathways and genes that regulate microglial function were identified through the integration of transcriptomics and metabolomics. Enzyme-Linked Immunosorbent Assay, Immunofluorescence, Western blot, Real-Time PCR, pHrodo, and Lyso-Tracker were employed to assess lysosomal and microglial function. In SAH mice, both neurological and microglial functions were significantly impaired on the first day but showed recovery over time. The combined results from transcriptomics and metabolomics identified 5-lipoxygenase (5-LOX) as a key target in regulating microglial function post-SAH. Administering resolvin D1 (RvD1) exogenously to inhibit 5-LOX nuclear translocation or directly supplementing lipoxin A4 (LXA4) to adjust the leukotriene B4 (LTB4)/LXA4 ratio, can improve lysosomal acidification, mitigate impaired lysosomal function, and enhance phagocytosis while reducing the inflammatory response. Protecting microglial function can also be achieved through JNJ or P2X purinoceptor 7 (P2X7) siRNA, which inhibit calcium/calmodulin-dependent protein kinase II (CaMKII) activation, prevent 5-LOX nuclear translocation, and improve lysosomal function. Furthermore, P2X7 siRNA also improved neurological function, lysosomal function and microglial function in SAH mice. Activation of P2X7-CaMKII after SAH promotes 5-LOX nuclear translocation, increases the LTB4/LXA4 ratio, elevates intracellular Ca2+ concentration, and impairs lysosomal and microglial function.