Expression and localization of angiogenic inhibitory factor, chondromodulin-I, in adult rat eye.
OBJECTIVE
To determine the role in the eye of chondromodulin (ChM)-I, which has been identified in cartilage as an angiogenic inhibitor, the expression and localization and a possible function of ChM-I were investigated.


METHODS
Expression and localization of ChM-I in rat eyes were examined by RNase protection assay and in situ hybridization and by immunostaining, using an antibody against a synthetic peptide. The effect of recombinant ChM-I on tube morphogenesis of retinal endothelial cells was examined in culture.


RESULTS
The rat ChM-I gene was determined to encode the open reading frame of 334 amino acid residues, and ChM-I mRNA was exclusively expressed in cartilage, eye, and cerebellum in rats. ChM-I mRNA expression was evident in the iris-ciliary body, retina, and scleral compartments, but not in other compartments of the eye. In situ hybridization revealed mRNA expression in the ganglion cells, inner nuclear layer cells, and pigment epithelium in the retina and in the nonpigment epithelium of the ciliary body. Immunoreactive ChM-I was present in these cells and also in the vitreous body. Western blot analysis detected an approximately 25-kDa band of ChM-I presumed as a secretory form in the aqueous humor and vitreous body and an approximately 37-kDa band as a precursor form in the retina. Recombinant human ChM-I inhibited tube morphogenesis of human retinal endothelial cells in vitro.


CONCLUSIONS
These observations indicate a potential role for ChM-I in inhibition of angiogenesis in the rat eye.
Funaki
H
H
Department of Structural Pathology, Institute of Nephrology, Niigata University, 1-757 Asahimachi-dori, Niigata 951-8510, Japan.
Sawaguchi
S
S
Yaoeda
K
K
Koyama
Y
Y
Yaoita
E
E
Funaki
S
S
Shirakashi
M
M
Oshima
Y
Y
Shukunami
C
C
Hiraki
Y
Y
Abe
H
H
Yamamoto
T
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects; D002924:Ciliary Body / Q000378:metabolism; D004730:Endothelium, Vascular / Q000187:drug effects; D004847:Epithelial Cells / Q000378:metabolism; D005123:Eye / Q000378:metabolism*; D005136:Eye Proteins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D006133:Growth Substances / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D023282:Nuclease Protection Assays; D010857:Pigment Epithelium of Eye / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D011921:Rats, Inbred WKY; D012160:Retina / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000378:metabolism; D012590:Sclera / Q000378:metabolism
C489407:Cnmd protein, rat; D005136:Eye Proteins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger