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 Roryt, 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 during neuroinflammation. On the other hand, the increased secretion of CCL2 with concomitant reduction of Shh might promote leukocytes extravasation into the brain parenchyma.
Ectonucleotidase activity and immunosuppression in astrocyte-CD4 T cell bidirectional signaling / F. Filipello, D. Pozzi, M. Proietti, A. Romagnani, S. Mazzitelli, M. Matteoli, C. Verderio, F. Grassi. - In: ONCOTARGET. - ISSN 1949-2553. - 7:5(2016 Feb 02), pp. 5143-5156.
|Titolo:||Ectonucleotidase activity and immunosuppression in astrocyte-CD4 T cell bidirectional signaling|
FILIPELLO, FABIA (Primo)
POZZI, DAVIDE (Secondo)
GRASSI, FABIO MARIA (Ultimo)
|Parole Chiave:||Astrocyte; Calcium; Ectonucleotidase; Immune response; Immunity; Immunology and Microbiology Section; Immunosuppression; T cell; 5'-Nucleotidase; Antigens, CD; Astrocytes; CD4-Positive T-Lymphocytes; Cell Differentiation; Humans; Signal Transduction; Up-Regulation; Oncology|
|Settore Scientifico Disciplinare:||Settore BIO/13 - Biologia Applicata|
|Data di pubblicazione:||2-feb-2016|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.18632/oncotarget.6914|
|Appare nelle tipologie:||01 - Articolo su periodico|