A2E Distribution in RPE Granules in Human Eyes
Ziqiang Guan1, Yiwen Li2, Shuliang Jiao3
1Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
Molecules (Basel, Switzerland)
|April 5, 2020
Summary
Researchers identified a novel, abundant RPE lipofuscin population rich in A2E, a major fluorophore in the retinal pigment epithelium. This discovery advances understanding of A2E and lipofuscin in human RPE.
Area of Science:
- Ophthalmology
- Cell Biology
- Biochemistry
Background:
- A2E (N-retinylidene-N-retinylethanolamine) is a key fluorophore within the retinal pigment epithelium (RPE).
- Lipofuscin accumulation in RPE is linked to age-related macular degeneration and other retinal diseases.
Purpose of the Study:
- To identify and characterize A2E-rich RPE lipofuscin granules.
- To determine the distribution and abundance of A2E within different RPE granule fractions.
Main Methods:
- Fractionation of human RPE granules using sucrose density gradient centrifugation.
- Quantification of A2E via liquid chromatography/mass spectrometry (LC/MS).
- Characterization of autofluorescence emission using a custom spectro-fluorometer.
Main Results:
- A significant A2E level was detected in all five RPE granule fractions (F1-F5).
- Fraction F1, a low-density fraction, comprised half the total RPE granule weight, contained 67% of all A2E, and emitted 75% of total autofluorescence.
- A novel, abundant RPE lipofuscin population was identified in fraction F1.
Conclusions:
- The study identified a previously undescribed, major population of RPE lipofuscin granules.
- This A2E-rich fraction is the most abundant lipofuscin granule population in human RPE.
- Understanding this RPE lipofuscin population is crucial for insights into A2E and RPE aging.
Keywords:
A2E (N-retinylidene-N-retinylethanolamine)RPE lipofuscinlipofuscin fluorescenceliquid chromatography/mass spectrometry (LC/MS), melaninretina
