Gene expression and functional studies of the optic nerve head astrocyte transcriptome from normal African Americans and Caucasian Americans donors.
OBJECTIVE
To determine whether optic nerve head (ONH) astrocytes, a key cellular component of glaucomatous neuropathy, exhibit differential gene expression in primary cultures of astrocytes from normal African American (AA) donors compared to astrocytes from normal Caucasian American (CA) donors.


METHODS
We used oligonucleotide Affymetrix microarray (HG U133A & HG U133A 2.0 chips) to compare gene expression levels in cultured ONH astrocytes from twelve CA and twelve AA normal age matched donor eyes. Chips were normalized with Robust Microarray Analysis (RMA) in R using Bioconductor. Significant differential gene expression levels were detected using mixed effects modeling and Statistical Analysis of Microarray (SAM). Functional analysis and Gene Ontology were used to classify differentially expressed genes. Differential gene expression was validated by quantitative real time RT-PCR. Protein levels were detected by Western blots and ELISA. Cell adhesion and migration assays tested physiological responses. Glutathione (GSH) assay detected levels of intracellular GSH.


RESULTS
Multiple analyses selected 87 genes differentially expressed between normal AA and CA (P<0.01). The most relevant genes expressed in AA were categorized by function, including: signal transduction, response to stress, ECM genes, migration and cell adhesion.


CONCLUSIONS
These data show that normal astrocytes from AA and CA normal donors display distinct expression profiles that impact astrocyte functions in the ONH. Our data suggests that differences in gene expression in ONH astrocytes may be specific to the development and/or progression of glaucoma in AA.
Miao
Haixi
H
Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
Chen
Lin
L
Riordan
Sean M
SM
Li
Wenjun
W
Juarez
Santiago
S
Crabb
Andrea M
AM
Lukas
Thomas J
TJ
Du
Pan
P
Lin
Simon M
SM
Wise
Alexandria
A
Agapova
Olga A
OA
Yang
Ping
P
Gu
Charles C
CC
Hernandez
M Rosario
MR
D001253:Astrocytes / Q000502:physiology*; D044383:Black People / Q000235:genetics*; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D016207:Cytokines / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D005978:Glutathione / Q000378:metabolism; D006133:Growth Substances / Q000235:genetics; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis; D009900:Optic Nerve / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D044465:White People / Q000235:genetics*; D001741:Black or African American
D016207:Cytokines; D006133:Growth Substances; D005978:Glutathione