Ca(2+) -related signaling events influence TLR9-induced IL-10 secretion in human B cells.
Suppressory B-cell function controls immune responses and is mainly dependent on IL-10 secretion. Pharmacological manipulation of B-cell-specific IL-10 synthesis could, thus, be therapeutically useful in B-cell chronic lymphocytic leukemia, transplantation, autoimmunity and sepsis. TLR are thought to play a protagonistic role in the formation of IL-10-secreting B cells. The aim of the study was to identify the molecular events selectively driving IL-10 production in TLR9-stimulated human B cells. Our data highlight the selectivity of calcineurin inhibitors in blocking TLR9-induced B-cell-derived IL-10 transcription and secretion, while IL-6 transcription and release, B-cell proliferation, and differentiation remain unaffected. Nevertheless, TLR9-induced IL-10 production was found to be independent of calcineurin phosphatase activity and was even negatively regulated by NFAT. In contrast to TLR9-induced IL-6, IL-10 secretion was highly sensitive to targeting of spleen tyrosine kinase (syk) and Bruton's tyrosine kinase. Further analyses demonstrated increased phosphorylation of Ca(2+) /calmodulin kinase II (CaMKII) in TLR9-stimulated B cells and selective reduction of TLR9-induced secretion of IL-10 upon treatment with CaMKII inhibitors, with negligible impact on IL-6 levels. Altogether, our results identify calcineurin antagonists as selective inhibitors of IL-10 transcription and syk/Bruton´s tyrosine kinase-induced Ca(2+) /calmodulin- and CaMKII-dependent signaling as a pathway regulating the release of TLR9-induced B-cell-derived IL-10.
Department of Infectious Diseases, University Hospital Heidelberg, Heidelberg, Germany.
Saskia
S
Ziegler
Katrin
K
Gartner
Uwe
U
Scheuermann
Tanja
T
Zoeller
Julia
J
Hantzschmann
Benjamin
B
Over
Sandra
S
Foermer
Klaus
K
Heeg
Isabelle
I
Bekeredjian-Ding
D000077329:Agammaglobulinaemia Tyrosine Kinase; D016175:B-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D019703:Calcineurin / Q000276:immunology / Q000378:metabolism; D065095:Calcineurin Inhibitors; D020013:Calcium Signaling / Q000502:physiology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism; D049109:Cell Proliferation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D016753:Interleukin-10 / Q000276:immunology* / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis / Q000276:immunology; D047908:Intracellular Signaling Peptides and Proteins / Q000276:immunology / Q000378:metabolism; D008297:Male; D050778:NFATC Transcription Factors / Q000276:immunology / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000276:immunology / Q000378:metabolism; D000072377:Syk Kinase; D051217:Toll-Like Receptor 9 / Q000276:immunology*; D014158:Transcription, Genetic / Q000502:physiology*
D065095:Calcineurin Inhibitors; D004791:Enzyme Inhibitors; C508609:IL10 protein, human; C508600:IL6 protein, human; D015850:Interleukin-6; D047908:Intracellular Signaling Peptides and Proteins; D050778:NFATC Transcription Factors; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9; D016753:Interleukin-10; D011505:Protein-Tyrosine Kinases; D000077329:Agammaglobulinaemia Tyrosine Kinase; C000606896:SYK protein, human; D000072377:Syk Kinase; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D019703:Calcineurin
B cells; Cytokines; Immune regulation; Immunotherapy; Toll-like receptors