An Ex Vivo Technique to Induce Neuronal Death via Oligodendrocyte-Specific CD8+ T Cells
내레이션 대본
Oligodendrocytes, which are specialized cells of the central nervous system, form myelin sheaths around neurons. Myelin insulates the axon and facilitates the rapid conduction of electrical impulses. Demyelination — the destruction of myelin — leads to neuronal death.
To study neuronal death, take a transgenic mouse brain fixed on a vibratome plate. Immerse the brain in an ice-cold buffer, preserving the structural integrity while sectioning.
Using a vibratome, obtain thin coronal sections. Transfer the sections to a culture well containing an appropriate medium.
The oligodendrocytes in the transgenic mouse brain express a foreign antigen, which is displayed on the cell surface via the major histocompatibility complex.
Add a solution of activated CD8+ T cells — specific for the foreign antigen — onto the sections and incubate.
The T cell receptor binds to its antigen displayed on the oligodendrocyte. The co-stimulatory molecule binds to its ligand. The binding initiates a signaling cascade inside the T cell, causing the release of perforin and granzymes — cytotoxic mediators.
Perforin creates pores in the oligodendrocyte membrane, through which granzymes enter the cytoplasm. Further, Fas ligands on the T cells bind to their receptors on the oligodendrocyte surface. Granzymes, along with the Fas ligand binding, induce the apoptotic pathway in oligodendrocytes, leading to demyelination and neuronal death.
Post-incubation, the treated brain sections are ready for the assessment of cell death.
