TSPO (translocator protein) is a mitochondrial membrane protein with multifaceted physiological roles. Molecularly, TSPO functions as a cholesterol-dependent protoporphyrin IX oxygenase 1, binding cholesterol and porphyrins to facilitate their metabolism. The protein regulates cholesterol transport across mitochondrial membranes and influences cellular metabolism 2, though its contribution to steroid hormone biosynthesis appears minimal 2. TSPO was initially identified as a peripheral benzodiazepine receptor and binds various ligands including isoquinoline carboxamides. In pathophysiology, TSPO expression is markedly upregulated in brain injury, inflammation, and cancer 3. Critically, TSPO elevation correlates with microglial activation and neuroinflammation in neurodegenerative diseases 3. In Alzheimer's disease, TSPO is primarily expressed in phagocytic (CD68+) microglia, reflecting ongoing neurodegeneration 4. TSPO uptake correlates with amyloid-β deposition and cognitive decline 5. TSPO also responds to diverse stressors (psychological and physical) in psychiatric and stress-related disorders 6. Clinically, TSPO PET imaging serves as a valuable neuroinflammation biomarker 7, though limitations include lack of cellular specificity and inability to distinguish neuroprotective from neurotoxic inflammation. TSPO knockout studies confirm its essential role in mitochondrial respiration and cellular metabolism 2, establishing it as both a biomarker and potential therapeutic target for neuroinflammatory conditions.