2-deoxy D-glucose prevents cell surface expression of NKG2D ligands through inhibition of N-linked glycosylation.
NKG2D ligand surface expression is important for immune recognition of stressed and neotransformed cells. In this study, we show that surface expression of MICA/B and other NKG2D ligands is dependent on N-linked glycosylation. The inhibitor of glycolysis and N-linked glycosylation, 2-deoxy-D-glucose (2DG), potently inhibited surface expression of MICA/B after histone deacetylase inhibitor treatment; the inhibition occurred posttranscriptionally without affecting MICA promoter activity. Transient overexpression of MICA surface expression was also inhibited by 2DG. 2DG blocks N-linked glycosylation of MICA/B by a reversible mechanism that can be alleviated by addition of d-mannose; this does not, however, affect the inhibition of glycolysis. Addition of d-mannose restored MICA/B surface expression after 2DG treatment. In addition, specific pharmacological or small interfering RNA-mediated targeting of glycolytic enzymes did not affect MICA/B surface expression, strongly suggesting that N-linked glycosylation, and not glycolysis, is essential for MICA/B surface expression. Corroborating this, tunicamycin, a selective inhibitor of N-linked glycosylation, abolished MICA/B surface expression without compromising activation of MICA promoter activity. NK cell-mediated killing assay and staining with a recombinant NKG2D-Fc fusion protein showed that all functional NKG2D ligands induced by histone deacetylase inhibitor treatment were abolished by 2DG treatment and fully reconstituted by further addition of d-mannose. Our data suggest that posttranslational N-linked glycosylation is strictly required for NKG2D ligand surface expression. Cancer and infection often result in aberrant glycosylation, which could likely be involved in modulation of NKG2D ligand expression. Our data further imply that chemotherapeutic use of 2DG may restrict NKG2D ligand surface expression and inhibit secretion of immunoinhibitory soluble NKG2D ligands.
Laboratory of Immunology, Faculty of Life Sciences, University of Copenhagen, 1870 Frederiksberg C, Denmark.
Lars
L
Andresen
Sarah Line
SL
Skovbakke
Gry
G
Persson
Michael
M
Hagemann-Jensen
Karen Aagaard
KA
Hansen
Helle
H
Jensen
Søren
S
Skov
D045744:Cell Line, Tumor; D003847:Deoxyglucose / Q000378:metabolism*; D006019:Glycolysis / Q000187:drug effects; D006031:Glycosylation; D057809:HEK293 Cells; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism; D008024:Ligands; D008358:Mannose / Q000494:pharmacology; D008565:Membrane Proteins / Q000096:biosynthesis / Q000276:immunology; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
D015395:Histocompatibility Antigens Class I; D056572:Histone Deacetylase Inhibitors; C527085:KLRK1 protein, human; D008024:Ligands; C099187:MHC class I-related chain A; C098080:MICB antigen; D008565:Membrane Proteins; D055655:NK Cell Lectin-Like Receptor Subfamily K; D034741:RNA, Small Interfering; D014415:Tunicamycin; D003847:Deoxyglucose; D008358:Mannose