Similarity of mRNA phenotypes of morphologically normal macular and peripheral retinal pigment epithelial cells in older human eyes.
OBJECTIVE
To determine the expression profiles of morphologically normal human retinal pigment epithelial (RPE) cells that originate from the macula and periphery.


METHODS
Morphologically normal RPE cells from 15 human globes from donors aged 52 to 82 years old were laser capture microdissected. Total RNA from 5000 cells was SMART amplified, [33]P-labeled, and hybridized to a cDNA array containing 4325 known genes. Expression profiles were analyzed by hierarchical cluster analysis, Prediction Analysis of Microarrays (PAM), and Significance Analysis for Microarrays (SAM). Differentially expressed genes were evaluated further by real time RT-PCR.


RESULTS
The overall expression profiles of RPE cells from the macula and periphery were similar. Unsupervised and supervised hierarchical cluster analysis showed that patient genotype was a stronger separating factor than topographical location. SAM analysis identified 11 genes that were underexpressed by macular RPE cells. The expression patterns of these 11 genes were confirmed by real time RT-PCR, with 5 genes reaching statistical significance.


CONCLUSIONS
Whereas the overall expression profiles were similar between cells from the macula and periphery, subtle differential expression of five genes could contribute to RPE phenotypic differences based on topographic location.
Michael Panitch Macular Degeneration Laboratory, Wilmer Eye Institute, Johns Hopkins Medical Institutes, Baltimore, Maryland 21287, USA.
Kazuki
K
Ishibashi
Jane
J
Tian
James T
JT
Handa
D000368:Aged; D000369:Aged, 80 and over; D016570:Bruch Membrane / Q000033:anatomy & histology; D020869:Gene Expression Profiling; D006801:Humans; D008266:Macula Lutea / Q000166:cytology / Q000378:metabolism*; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010857:Pigment Epithelium of Eye / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger