Inhibitory effects of neurocan and phosphacan on neurite outgrowth from retinal ganglion cells in culture.
OBJECTIVE
Neurocan and phosphacan are nervous tissue-specific chondroitin sulfate proteoglycans (CSPGs) that are highly expressed in postnatal rat retina. To elucidate potential roles of neurocan and phosphacan on neurite outgrowth from retinal ganglion cells (RGCs), in vitro experiments were conducted with purified RGCs.


METHODS
Neurocan and phosphacan were purified from postnatal rat brain by DEAE-column chromatography and subsequent gel chromatography. RGCs were obtained from postnatal rat retinas by a two-step immunopanning procedure using an anti-Thy 1,1 antibody and an anti-macrophage antibody. Neurite outgrowth from RGCs was examined on poly-L-lysine (PLL)-conditioned plates, and PLL-conditioned plates treated with neurocan or phosphacan.


RESULTS
Compared with PLL-conditioned plates, neurocan and phosphacan inhibited neurite outgrowth from RGCs at 48 and 72 hours after seeding. When chondroitin sulfate side chains linked to the core proteins were digested by chondroitinase ABC, the inhibitory effect remained, indicating that the core proteins are related to the effect. Furthermore, the digestion of chondroitin sulfate side chains linked to phosphacan core protein significantly promoted the inhibitory effect of phosphacan on neurite outgrowth from RGCs.


CONCLUSIONS
Neurocan and phosphacan, which are highly expressed in postnatal rat retina, inhibit neurite outgrowth from postnatal rat RGCs, indicating that these proteoglycans may be inhibitory factors against neurite outgrowth from RGCs during retinal development.
Inatani
M
M
Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Japan.
Honjo
M
M
Otori
Y
Y
Oohira
A
A
Kido
N
N
Tano
Y
Y
Honda
Y
Y
Tanihara
H
H
D000818:Animals; D001923:Brain Chemistry; D002478:Cells, Cultured; D011508:Chondroitin Sulfate Proteoglycans / Q000302:isolation & purification / Q000494:pharmacology*; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D037181:Lectins, C-Type; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D016501:Neurites / Q000187:drug effects* / Q000502:physiology; D058580:Neurocan; D051381:Rats; D017207:Rats, Sprague-Dawley; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000187:drug effects*
D011508:Chondroitin Sulfate Proteoglycans; D037181:Lectins, C-Type; D009419:Nerve Tissue Proteins; D058580:Neurocan; C076817:NCAN protein, human; C516895:PTPRZ1 protein, human; C516897:Ptprz1 protein, rat; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5