Dissertation (Metadaten)
Titel:Charakterisierung der molekularen Rolle von Caspasen bei der Proliferation von Fibroblasten und T-Lymphozyten
Autor:Markus Falk
Fakultät:Mathematisch-Naturwissenschaftliche Fakultät
DDC Sachgebiet:610 Medizin und Gesundheit
Datum der mdl. Prüfung:08.02.2005
Referent(in):Prof. Dr. Dr. S. Bulfone-Paus
Korreferent(en) Korreferentin:Prof. Dr. T. Bosch
Beschreibung (original):(Keine Zusammenfassung in deutscher Sprache hinterlegt.)
(übersetzt):Recently the proapoptotic caspase family has been described to be involved also in proliferative processes. Initially, in this work, the relevance of the FADD/Caspase signaling pathway for cell growth was investigated using murine fibroblasts. Expression of a dominant-negative FADD mutant caused a reduced growth rate of these cells compared to the wildtype. Subsequently the molecular contribution of caspases during mitogen-induced proliferation of human T lymphocytes was characterized. Experiments using human T cells showed an impaired proliferative response of mitogen-activated T cells, when caspase activity was blocked by pharmacological inhibitors. Moreover, caspase inhibition led to a G1-cell cycle arrest of cells and caused inappropriate regulation of cell cycle-associated proteins. Proliferation assays implicated a positive contribution of caspases to the autocrine IL-2/IL-2R system, since exogeneous IL-2 could partially revert the proliferative defects mediated by caspase inhibitors. Along those lines, caspase inhibition caused a strong reduction in the activation-induced IL-2 secretion of primary T cells. Jurkat T cells lacking functional caspase-8 also exhibited a disability to produce physiological amounts of IL-2. This inhibition occurred at the transcriptional level as shown by quantitative RT-PCR. Luciferase-reporter assays using the human T cell line Jurkat revealed an impaired transcriptional activity of NFkB and the composite RE/AP element within the IL-2 promoter. Finally, caspases might be involved in activation-induced cytokine production of human monocytes, since caspase inhibition led to a reduced TNF secretion after stimulation with bacterial antigens.
Schlagworte:Caspasen, T-Zellen, Proliferation, Apoptose, Fibroblasten, Fas, Zelltod
d1357.pdf (2.908 kB)    ZIP generieren   Details >>