title: Zinc induced apoptotic death of mouse dendritic cells.
abstract: Zinc ions (Zn(2+)) are food components with favourable effects in infectious disease. Zn(2+) is taken up into dendritic cells (DCs), key players in the regulation of innate and adaptive immunity. In other cell types, Zn(2+) has been shown to stimulate the formation of ceramide, which is in turn known to trigger suicidal cell death. The present study explored whether Zn(2+) modifies ceramide formation and survival of bone marrow derived DCs. To this end, DCs were isolated from acid sphingomyelinase knockout (asm (-/-)) and corresponding wild type (asm (+/+)) mice and treated with different concentrations of Zn(2+). Ceramide formation was assessed with anti-ceramide antibodies in FACS and immunohistochemical analysis, sub-G1 cell population by FACS analysis, break down of phosphatidylserine asymmetry by annexin V binding, cell death by propidium iodide incorporation, metabolic cell activity by MTT assay, ROS production from dichlorofluorescein fluorescence and activation of MAPKs by Western blotting. The treatment of asm (+/+) DCs with low Zn(2+) concentrations (up to 100 μM) was followed by ceramide formation, increase in sub-G1 cell population and phosphatidylserine exposure, effects blunted in asm (-/-) DCs. The treatment of DCs with C2-ceramide increased the percentage of sub-G1 and apoptotic DCs from both genotypes. Zn(2+) led to similar activation of MAPKs in asm (+/+) and asm (-/-) DCs and did not affect ROS production. Higher concentrations of Zn(2+) led to a marked increase of propidium iodide incorporation in DCs of both genotypes. The present study reveals that in DCs Zn(2+) triggers ceramide formation, which in turn compromises cell survival.
authors.affiliation: Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Shumilina
authors.forename: Nguyen Thi
authors.initials: NT
authors.lastname: Xuan
authors.forename: Evi
authors.initials: E
authors.lastname: Schmid
authors.forename: Shefalee K
authors.initials: SK
authors.lastname: Bhavsar
authors.forename: Kalina
authors.initials: K
authors.lastname: Szteyn
authors.forename: Shuchen
authors.initials: S
authors.lastname: Gu
authors.forename: Friedrich
authors.initials: F
authors.lastname: Götz
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000032:analysis; D017209:Apoptosis / Q000187:drug effects*; D051940:B7-2 Antigen / Q000032:analysis; D002518:Ceramides / Q000096:biosynthesis*; D003713:Dendritic Cells / Q000187:drug effects* / Q000502:physiology; D005434:Flow Cytometry; D055786:Gene Knockout Techniques; D015151:Immunoblotting; D051379:Mice; D018345:Mice, Knockout; D017382:Reactive Oxygen Species / Q000378:metabolism; D013108:Sphingomyelin Phosphodiesterase / Q000235:genetics; D015032:Zinc / Q000494:pharmacology*
chemical_list: D017304:Annexin A5; D051940:B7-2 Antigen; D002518:Ceramides; D017382:Reactive Oxygen Species; D013108:Sphingomyelin Phosphodiesterase; D015032:Zinc