The cellular expression of antiangiogenic factors in fetal primate macula.
OBJECTIVE
To characterize the cellular expression patterns of antiangiogenic factors differentially regulated in the fetal human macula.


METHODS
RNA was extracted from macular, nasal, and surround biopsies of three human fetal retinas at midgestation. Relative levels of expression of pigment epithelium-derived factor (PEDF), brain natriuretic peptide (BNP), collagen type IValpha2 (COL4A2), and natriuretic peptide receptors A and C (NPRA and NPRC) were determined with quantitative PCR. Cellular expression of PEDF and BNP was investigated by in situ hybridization on retinal sections from monkeys aged between fetal day 55 and 11 years. BNP, COL4A2, and NPRA proteins were localized by immunohistochemistry. Labeling was imaged and quantified by confocal microscopy and optical densitometry.


RESULTS
Quantitative PCR confirmed higher levels of PEDF and BNP and lower levels of COL4A2 in the macula at midgestation. PEDF mRNA was detected in ganglion cells (GCs) and the pigment epithelium (RPE). BNP mRNA was detected in GCs and macroglia, although BNP immunoreactivity (IR) was predominantly perivascular. COL4A2-IR was detected in large blood vessels and NPRA-IR on the retinal vascular endothelium, GC axons in fetal retinas, and cone axons at all ages. Optical densitometry showed a graded expression of PEDF and BNP at all ages, with highest levels of expression in GCs in the developing fovea.


CONCLUSIONS
Because the retinal vessels initially form in the GC layer, it is likely that PEDF has a key role in defining and maintaining the foveal avascular area. The precise role of BNP is unclear, but it may include both antiangiogenic and natriuretic functions.
Kozulin
Peter
P
ARC Centre of Excellence in Vision Science and Research School of Biology, The Australian National University, Canberra, ACT, Australia. peter.kozulin@anu.edu.au
Natoli
Riccardo
R
Bumsted O'Brien
Keely M
KM
Madigan
Michele C
MC
Provis
Jan M
JM
D000818:Animals; D024141:Collagen Type IV / Q000235:genetics* / Q000378:metabolism; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D005865:Gestational Age; D006801:Humans; D017403:In Situ Hybridization; D008251:Macaca; D008266:Macula Lutea / Q000196:embryology* / Q000378:metabolism; D017628:Microglia / Q000378:metabolism; D018613:Microscopy, Confocal; D020097:Natriuretic Peptide, Brain / Q000235:genetics* / Q000378:metabolism; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D017461:Receptors, Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000378:metabolism; D012171:Retinal Vessels / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015843:Serpins / Q000235:genetics* / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
D024141:Collagen Type IV; D005136:Eye Proteins; D020097:Natriuretic Peptide, Brain; D009414:Nerve Growth Factors; D012333:RNA, Messenger; D017461:Receptors, Atrial Natriuretic Factor; D015843:Serpins; D000099174:Pigment Epithelium-Derived Factor; C502625:COL4A2 protein, human; C091715:atrial natriuretic factor receptor A; C073616:atrial natriuretic factor receptor C