Fig. 6

Potential mechanisms involved in TSPO overexpression in response to sustained CNTF exposure. Neurons were infected by a lentiviral vector (LVn) encoding for CNTF. CNTF was then released and induced a TSPO overexpression in astrocytes, microglia and neurons. Astrocytes are the first mediators of this response, through the JAK2-STAT3 pathway. The TSPO overexpression in microglia may be due to the release of cytokines by astrocytes in the extracellular space. Nevertheless, CNTF could also be directly responsible of a part of TSPO overexpression in microglia and neurons as both cell type present CNTF receptors. The dotted arrows represent hypothetical mechanisms not demonstrated in this study. The thick arrows highlight the major mechanisms involved in TSPO overexpression