title: A gene expression profile of the developing human retinal pigment epithelium.
abstract: OBJECTIVE
  The molecular mechanisms associated with human retinal pigment epithelium (RPE) development constitute the basis for cell replacement therapy for the treatment of retinal degenerative diseases. In the current study, gene expression analysis of the human fetal RPE during development was performed and was compared with the human native RPE.
  
  
  METHODS
  Microdissection of the human RPE at three time points (13 weeks and 16 weeks of gestation and in mature adult eyes) was performed, and total RNA was isolated. Equal amounts of RNA were pooled from two or three independent donor eyes for each time point in each group. Gene expression was analyzed by hybridization to microarray chips. Validation was accomplished by comparing the microarray expression proﬁles with quantitative real-time reverse transcriptase-polymerase chain reaction (qRT(2)-PCR) analysis of selected genes and by comparing selected expression proﬁles with predicted proﬁles based on previous studies.
  
  
  RESULTS
  Of the 45,033 probe sets on the microarray, 30,736 were detected. A total of 3,498 differentially expressed genes could be clustered into eight patterns of expression that were statistically significant. Analysis of the expression patterns of genes coding for key functions (pigment synthesis, visual cycle, phagocytosis, adherens and tight junctions, and transcellular transport) indicated that the human RPE achieves a high degree of maturity during early pregnancy. Compared with 154 signature genes in the RPE, 148 candidate genes were identified in this study, including 53 downregulated genes and 5 upregulated genes. The qRT(2)-PCR results showed similar expression trends to those obtained by microarray analysis at the three time points.
  
  
  CONCLUSIONS
  This study demonstrated gene expression profiles in the human RPE during normal development. These ﬁndings indicate that the human RPE has different expression patterns than those of other animals. The results of this study may be helpful in furthering the understanding of the developmental processes occurring in humans and of the differentiation of RPE cells derived from human embryonic stem cells and from human induced pluripotent stem cells.
authors.affiliation: Department of Ophthalmology, the Second Affiliated Hospital of Harbin Medical University, Harbin, China.
authors.forename: Zhongyu
authors.initials: Z
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huizhen
authors.initials: H
authors.lastname: Xiao
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Liang
authors.forename: Dawei
authors.initials: D
authors.lastname: Sun
authors.forename: Shaomin
authors.initials: S
authors.lastname: Peng
mesh_terms: D000328:Adult; D000818:Animals; D002454:Cell Differentiation; D005260:Female; D047109:Fetal Development / Q000235:genetics*; D005333:Fetus; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D005865:Gestational Age; D006801:Humans; D008875:Middle Aged; D005810:Multigene Family; D020411:Oligonucleotide Array Sequence Analysis; D011247:Pregnancy; D060888:Real-Time Polymerase Chain Reaction; D055213:Retinal Pigment Epithelium / Q000378:metabolism*