Abstract
Purpose:
Glaucoma is a neurodegenerative disease leading to apoptosis of retinal ganglion cells (rgc). Previous studies have been able to show an autoimmune component such as changes of autoantibody reactions in the serum. Studies also can demonstrate a significant effect of the serum of glaucoma patients on neuroretinal cells in vitro. Aim of this study was to analyze the effect of antibodies (Abs) from glaucoma patients on rgc in more detail.
Methods:
RGC5 cells were incubated with 5% FBS and 5% serum from healthy subjects, POAG patients or with 5% FBS plus the equivalent amount of Abs from glaucoma patients for 48h. Abs were isolated from the serum with protein G spin kit. Thereafter, the protein profiles of the cells were measured with LC-ESI-MSMS. Quantification was performed with PSP, an in-house software and pathway analysis with Ingenuity software.
Results:
1694 proteins were identified successfully, of which 198 were significantly differently regulated (< - 4 fold or > 4 fold difference) in cells incubated with POAG serum and 82 in cells incubated with POAG Abs. 56% of the proteins changed in cells incubated with POAG Abs were regulated in the same significant way in cells incubated with POAG serum, 34% were regulated in the same manner and only 6% of the proteins were regulated significantly differently. Pathway analysis showed that the proteins changed in the cells incubated with POAG Abs were involved in cell regulatory pathways e.g. GAS2 involved in cell shrinkage and blebbing or BAK, involved in the mitochondrial apoptosis pathway.
Conclusions:
The antibodies of glaucoma patients have significant effects on regulatory pathways in neuroretinal cells. Furthermore 90% of the changes seen in Ab incubated cells can be in cells incubated with glaucoma serum. The changes of natural autoantibodies of patients therefore could lead to a loss of protective autoimmunity and to a higher vulnerability of the cells towards external stress factors such as an elevated pressure