The death-receptors TRAMP and TRAIL are present in human Lens Epithelial Cells
J. F. Jordan, N. Kociok, J. M. Esser. T. T. Luther, P. Esser, G. K. Krieglstein
Introduction: Apoptosis is a physiological, energy-dependent process. The execution of the programmed cell death is initiated by extracellular death-ligands binding specifically to certain death-receptors. Thereby, an intracellular cascade is initiated leading finally to the death of the cell without causing any inflammatory side-effects.
Methods: Human lens epithelial cells (hLECs) were obtained from anterior lens capsules during cataract surgery. For isolation of total RNA, the tissue was transferred immediately into TRI-reagent and frozen. mRNA was isolated by phenol extraction and reversely transcribed. The expression of Fas/FasL, Apo-3L/TRAMP, TRAIL and TRAIL-R1-4 mRNA was investigated by RT-PCR using specific PCR primers. Amplification products were separated by agarose gel-electrophoresis and visualized with ethidiumbromide.
Results: The specific band for the corresponding primers could be detected for Fas and FasL, as well as for newly discovered death receptors from the TNF-receptor superfamily, i.g. TNF-receptor related apoptosis-mediated protein (TRAMP) and its ligand Apo-3L, and the TNF-related apoptosis-inducing ligand (TRAIL, APO-2) -receptors 2 and 3. No specific signal could be detected for the negative controls.
Conclusions: Here we demonstrate the presence of several apoptosis-mediating proteins in human lens epithelial cells. The expression of these death-receptors as well as of their corresponding ligands could have important implications on the therapeutic strategies regarding the prevention and treatment of posterior capsule opacification (PCO) after cataract surgery. As the LECs post-surgery seem to be a population of fast proliferating and thereby transforming cells, they could be an excellent target for a therapeutic approach of the proapoptotic effects of certain death-mediating proteins.
This study was supported by the Retinovit Foundation and the DFG (ES 82/5-3).
University Eye Hospital, University of Cologne, Joseph-Stelzmann-Str. 9, 50931 Cologne, Germany