Cytokine-induced release of ceramide-enriched exosomes as a mediator of cell death signaling in an oligodendroglioma cell line.
Th1 pro-inflammatory cytokines, i.e., TNF-α and IFN-γ, in combination are known to induce cell death in several cell types, including oligodendrocytes, but the mechanism of their synergistic cytotoxicity is unclear. Although ceramide (Cer) has been implicated in cytokine- and stress-induced cell death, its intracellular levels alone cannot explain cytokine synergy. We considered the possibility that Cer released as part of extracellular vesicles may contribute to cytokine-induced synergistic cell death. Using a human oligodendroglioma (HOG) cell line as a model, here we show that exosomes derived from TNF-α-treated "donor" cells, while being mildly toxic to fresh cultures (similar to individual cytokines), induce enhanced cell death when added to IFN-γ-primed target cultures in a fashion resembling the effect of cytokine combination. Further, the sphingolipid profiles of secreted exosomes, as determined by HPLC-MS/MS, revealed that the treatment with the cytokines time-dependently induced the formation and exosomal release, in particular of C16-, C24-, and C24:1-Cer species; C16-, C24-, and C24:1-dihydroCer species; and C16-, C24-, and C24:1-SM species. Finally, exogenous C6-Cer or C16-Cer mimicked and enhanced the cytotoxic effects of the cytokines upon HOG cells, thereby supporting the cell death-signaling role of extracellular Cer.
Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425.|Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425.|Laboratory of Signaling Proteins, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
Maria
M
Podbielska
Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425.
Zdzisław M
ZM
Szulc
Laboratory of Signaling Proteins, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 53-114 Wrocław, Poland.
Ewa
E
Kurowska
Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425.
Edward L
EL
Hogan
Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425.
Jacek
J
Bielawski
Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425.
Alicja
A
Bielawska
Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425 bhatnr@musc.edu.
Narayan R
NR
Bhat
D016923:Cell Death / Q000235:genetics; D045744:Cell Line, Tumor; D002518:Ceramides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D055354:Exosomes; D000067128:Extracellular Vesicles / Q000378:metabolism; D006801:Humans; D007371:Interferon-gamma / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism*; D009836:Oligodendroglia / Q000378:metabolism / Q000473:pathology; D009837:Oligodendroglioma / Q000378:metabolism* / Q000473:pathology; D013107:Sphingolipids / Q000737:chemistry / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage / Q000235:genetics / Q000378:metabolism*
D002518:Ceramides; D013107:Sphingolipids; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma
cell signaling; lipidomics; multiple sclerosis; oligodendrocyte; sphingolipids; vesicles