Müller and retinal pigment epithelial (RPE) cell expression of NGFI-A and c-fos mRNA in response to medium conditioned by the RPE.
Retinal pigment epithelial (RPE) cells secrete a factor(s) which promotes Müller and RPE cell survival and proliferation in vitro. These influences may play developmental and functional roles as well as contribute to ocular pathologies such as proliferative vitreoretinopathy (PVR). In the past few years, a number of immediate early genes (IEGs) have been identified. Many IBGs encode transcription factors, the expression of which is altered by stimuli such as growth factors. Since an RPE-derived factor(s) elicits proliferation of Müller and RPE cells, we investigated the expression of two IEGs, NGFI-A and c-fos, in both cell types after treatment with medium conditioned by the RPE (RPE-CM). We found that Müller and RPE cells had increased levels of NGFI-A mRNA following treatment with RPE-CM; in contrast, only a slight increase in c-fos mRNA was induced in RPE, but not Müller cells. Immunolabeling for NGFI-A protein revealed nuclear staining in both cell types which corresponded with the increased mRNA levels in RPE-CM-treated cultures. This in vitro study demonstrates a potential mechanism by which RPE-secreted factors may exert autocrine or paracrine effects on retinal cells in vivo. Specifically, NGFI-A may be the primary target of a second messenger system that is regulated by an RPE-derived factor(s).
Jaynes
C D
CD
Department of Anatomy and Cell Biology, University of North Texas Health Science Center, Fort Worth 76107, USA.
Sheedlo
H J
HJ
Agarwal
N
N
O'Rourke
K
K
Turner
J E
JE
D000818:Animals; D002455:Cell Division; D002478:Cells, Cultured / Q000276:immunology; D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins / Q000096:biosynthesis*; D051766:Early Growth Response Protein 1; D005123:Eye / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics*; D017781:Genes, Immediate-Early; D017874:Immediate-Early Proteins; D010857:Pigment Epithelium of Eye / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D014157:Transcription Factors / Q000096:biosynthesis*
D017077:Culture Media, Conditioned; D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D017874:Immediate-Early Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D014157:Transcription Factors