Ectonucleotidase activity and immunosuppression in astrocyte-CD4 T cell bidirectional signaling
Abstract
Astrocytes play a crucial role in neuroinflammation as part of the glia limitans, which regulates infiltration of the brain parenchyma by leukocytes. The signaling pathways and molecular events, which result from the interaction of activated T cells with astrocytes are poorly defined. Here we show that astrocytes promote the expression and enzymatic activity of CD39 and CD73 ectonucleotidases in recently activated CD4 cells by a contact dependent mechanism that is independent of T cell receptor interaction with class II major histocompatibility complex (MHC). Transforming growth factor-β (TGF-β) is robustly upregulated and sufficient to promote ectonucleotidases expression. T cell adhesion to astrocyte results in differentiation to an immunosuppressive phenotype defined by expression of the transcription factor Rorγt, which characterizes the CD4 T helper 17 subset. CD39 activity in T cells in turn inhibits spontaneous calcium oscillations in astrocytes that correlated with enhanced and reduced transcription of CCL2 chemokine and Sonic hedgehog (Shh), respectively. We hypothesize this TCR-independent interaction promote an immunosuppressive program in T cells to control possible brain injury by deregulated T cell activation duri...Continue Reading
References
Citations
Methods Mentioned
Software Mentioned
Related Concepts
Related Feeds
Brain Injury & Trauma
brain injury after impact to the head is due to both immediate mechanical effects and delayed responses of neural tissues.
Astrocytes
Astrocytes are glial cells that support the blood-brain barrier, facilitate neurotransmission, provide nutrients to neurons, and help repair damaged nervous tissues. Here is the latest research.
Astrocytes & Neurodegeneration
Astrocytes are important for the health and function of the central nervous system. When these cells stop functioning properly, either through gain of function or loss of homeostatic controls, neurodegenerative diseases can occur. Here is the latest research on astrocytes and neurodegeneration.