Galectin-1 induced activation of the apoptotic death-receptor pathway in human Jurkat T lymphocytes.
Galectin-1 (gal-1), a member of the family of beta-galactoside binding proteins, participates in several biological processes such as immunomodulation, cell adhesion, regulation of cell growth and apoptosis. The aim of this study was to investigate whether gal-1 interferes with the Fas (Apo-1/CD95)-associated apoptosis cascade in the T-cell lines Jurkat and MOLT-4. Gal-1 and an Apo-1 monoclonal antibody (mAb) induced DNA-fragmentation in Jurkat T-cells whereas MOLT-4 cells were resistant. Gal-1 stimulated DNA-fragmentation could be efficiently inhibited by caspase-8 inhibitor II (Z-IETD-FMK) and a neutralizing Fas mAb. Fas could be identified as a target for gal-1 recognition as demonstrated by immunofluorescence staining, binding of the receptor glycoprotein to immobilized gal-1 and analyses by immunoblotting as well as by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gal-1 stimulates the activation and proteolytic processing of procaspase-8 and downstream procaspase-3 in Jurkat-T cells. Inhibition of gal-1 induced procaspase-8 activation by a neutralizing Fas mAb strongly suggests that gal-1 recognition of Fas is associated with caspase-8 activation. Our data provide the first experimental evidence for targeting of gal-1 to glycotopes on Fas and the subsequent activation of the apoptotic death-receptor pathway.
Brandt
Bettina
B
Medical Faculty, Institute of Medical Biochemistry and Molecular Biology, University of Rostock, Schillingallee 70, 18057 Rostock, Germany.
Büchse
Tom
T
Abou-Eladab
Ehab Fathi
EF
Tiedge
Markus
M
Krause
Eberhard
E
Jeschke
Udo
U
Walzel
Hermann
H
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D061945:Caspase Inhibitors; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002853:Chromatography, Liquid; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects; D053222:Fas Ligand Protein / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D037483:Galectin 1 / Q000494:pharmacology* / Q000502:physiology; D006801:Humans; D015151:Immunoblotting; D019169:Jurkat Cells; D009842:Oligopeptides / Q000494:pharmacology; D053218:Receptors, Death Domain / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D053719:Tandem Mass Spectrometry; D019014:fas Receptor / Q000378:metabolism
D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D053222:Fas Ligand Protein; D037483:Galectin 1; D009842:Oligopeptides; D053218:Receptors, Death Domain; C403753:benzyloxycarbonyl-isoleucyl-glutamyl-threonyl-aspartic acid fluoromethyl ketone; D019014:fas Receptor; D053148:Caspase 3; D053181:Caspase 8