SPARC is a major secretory gene expressed and involved in the development of proliferative diabetic retinopathy.
OBJECTIVE
Neovascularization is an important event in proliferative diabetic retinopathy (PDR), where various secretory proteins including multiple growth factors are considered to be involved in this process. We searched for secretory proteins expressed in a surgical specimen obtained from the eyes of patients with PDR.


METHODS
We developed the oligo-cap signal sequence trap (SST) strategy which enables us to screen for secretory or membrane proteins from a minimal starting material. Using this method, we were able to screen a cDNA library constructed from a surgical specimen obtained from the eyes of the patients with PDR.


RESULTS
Majority of the cloned cDNAs turned out to encode secreted protein acidic and rich in cystein (SPARC), strongly suggesting that SPARC is highly expressed in PDR. Analysis of vitreous fluid from various patients has shown that the concentration of SPARC protein is increased in patients with PDR. Furthermore, subretinal injection of recombinant SPARC adenovirus induced PDR-like changes in the rat eye.


CONCLUSIONS
Our results strongly suggested that SPARC is involved in the development of diabetic retinopathy (DR).
Watanabe
Kazuhisa
K
Department of Internal Medicine (Endocrinology and Metabolism), Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
Okamoto
Fumiki
F
Yokoo
Tomotaka
T
Iida
Kaoruko Tada
KT
Suzuki
Hiroaki
H
Shimano
Hitoshi
H
Oshika
Tetsuro
T
Yamada
Nobuhiro
N
Toyoshima
Hideo
H
D000818:Animals; D003930:Diabetic Retinopathy / Q000209:etiology* / Q000473:pathology; D005136:Eye Proteins / Q000032:analysis* / Q000235:genetics; D015723:Gene Library; D006801:Humans; D015676:Osteonectin / Q000032:analysis*; D051381:Rats
D005136:Eye Proteins; D015676:Osteonectin