SIK2-P300 axis Orchestrates the metabolic reprogramming and Immunological functions in microglia of Alzheimer's disease mice via a dual modulation of lactylation and Acetylation: An epigenetic Perspective.

Metabolic dysfunction in microglia is increasingly recognized as a core driver of Alzheimer's disease (AD) pathogenesis, and yet the underlying mechanisms remain elusive. Here, we identified salt-inducible kinase 2 (SIK2) as a critical metabolic checkpoint that was downregulated in microglia across the AD mouse models (5 × FAD, APP/PS1, and SAMP8). We found that a loss of SIK2 in microglia induced a pro‑inflammatory phenotype, thus impairing amyloid β-protein (Aβ) phagocytosis and rewiring glucose and lipid metabolism toward enhanced glycolysis and lipid accumulation. Mechanistically, SIK2 directly interacted with the histone acetyltransferase P300; SIK2 deficiency increased the activity of P300, elevating H3K9 acetylation and H4K8/12 lactylation at promoters of metabolic genes. The microglia‑specific SIK2 overexpression in the 5 × FAD mice mitigated cognitive deficits, Aβ pathology, neuroinflammation, and aberrant histone modifications. A pharmacological inhibition of P300 regained these protective effects. Our findings highlight the SIK2-P300 epigenetic axis as a key regulator of the metabolic homeostasis in microglia and a potential therapeutic target for AD treatments.