Loth_columbia_0054D_14904.pdf [article]

Translocator Protein 18 kDa: from Biomarker to Function Meredith K. Loth Translocator Protein 18 kDa (TSPO) is a protein that is expressed at low levels in the brain, but upon brain injury or inflammation, increases its expression in the areas of the brain specific to injury. In this way, TSPO can be used as a biomarker of brain inflammation and injury. TSPO is primarily expressed in two cell types, microglia and astrocytes, and is used as a marker of reactive gliosis in various brain
more » ... s. Currently, there is a paucity of knowledge on the function(s) of TSPO in glial cells. Recent studies using conditional and global TSPO knockout mice have questioned the role of TSPO in translocating cholesterol across the outer mitochondrial membrane as the first step in steroidogenesis. In the brain, microglia and astrocytes exhibit distinct spatial and temporal patterns of TSPO upregulation. These differential patterns are not well characterized across disease models and in particular, are poorly characterized in the early stages of disease, prior to behavioral and clinical disease manifestations. Importantly, these distinct patterns of TSPO upregulation may indicate different functions of TSPO in microglia and astrocytes. We examined TSPO levels in a neurodegenerative transgenic mouse model of Sandhoff disease and longitudinally compared TSPO levels to behavioral manifestations of disease and other neuropathological endpoints (neurodegeneration, reactive gliosis, ganglioside accumulation). This study confirmed TSPO upregulation prior to neurodegeneration in a brain region-dependent and disease course-dependent way. In brain regions with increased TSPO levels, there was a differential pattern of glial cell activation with astrocytes being activated earlier than microglia during the progression of disease. Immunofluorescent confocal imaging confirmed that TSPO i
doi:10.7916/d8f77wg5 fatcat:7oebm6ysx5bwnn6quqdqcdzpge