Abstract
Purpose: :
To determine Bruch’s membrane protein profile changes during the aging process and development of AMD.
Methods: :
An excimer laser was used to harvest 6.5 mm circular explants of human Bruch’s membrane from fresh (<24 hours) young (<55, n = 6) and old (>65, n = 6) human donors. Eyes with AMD (n = 4) were identified under a dissecting scope and graded. Proteins were extracted using an optimized extraction protocol and separated using 2-D gel electrophoresis. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and electrospray ionization-quadruple time-of-flight MS/MS (ESI-Q-TOF MS/MS) were used to identify the mapped proteins. Spots common in >2/3 of the gels were compared between the groups to determine the age and AMD-specific differences in Bruch’s membrane proteome. Results were confirmed with Western blotting analysis.
Results: :
132 common proteins were identified in young human Bruch’s membrane proteome. Aging resulted in a divergence of protein expression which resulted in a decrease of common proteins down to 95. Variations in protein expression were further exacerbated with AMD which resulted in only 49 preserved common proteins. Qualitative analyses revealed that age related macular degeneration was associated with an increased amount of complement factors (C1q, C3, C7, C8 and Factor H) and hemoglobin beta chain within Bruch’s membrane.
Conclusions: :
Human Bruch’s membrane proteome reveals specific changes by aging and development of AMD. These changes reflect cumulative pathological events and cellular adaptive processes. Qualitative and quantitative changes in Bruch’s membrane proteome may take part in pathobiology of AMD by augmenting the cellular damage.
Keywords: age-related macular degeneration • Bruch's membrane • proteomics