The DSD-1 carbohydrate epitope depends on sulfation, correlates with chondroitin sulfate D motifs, and is sufficient to promote neurite outgrowth.
The neural chondroitin sulfate (CS) proteoglycan (PG) DSD-1-PG was originally identified with the monoclonal antibody (mAb) 473HD. It promotes neurite outgrowth of hippocampal neurons when coated as a substrate in the presence of polycations. This effect is inhibited by mAb 473HD that specifically recognizes the DSD-1 epitope. The DSD-1 epitope is also detectable in CS-C and CS-D preparations from shark cartilage but not in other chondroitin sulfates that are structurally related and differ in their sulfation patterns. Non-sulfated DSD-1-PG and chemically desulfated CS-D were not recognized by mAb 473HD, suggesting that the DSD-1 epitope depends on sulfation. It was possible to enrich DSD-1 epitope-bearing carbohydrates and D disaccharide units from CS-C and CS-D preparations on a mAb 473HD affinity matrix. This indicates that the DSD-1 epitope represents a distinct glycosaminoglycan structure containing D units. The analysis of glycosaminoglycan digestion products by high pressure liquid chromatography revealed that DSD-1-PG preparations contain a unique D disaccharide unit as well as an A, a C, and a non-sulfated disaccharide unit. In neurite outgrowth assays with hippocampal neurons, substrate-bound CS-D promoted neurite outgrowth, whereas CS-A, CS-B, or CS-C did not. This effect of CS-D was inhibited by mAb 473HD. DSD-1 epitope-enriched fractions obtained from CS-D and CS-C promoted neurite outgrowth, whereas CS-C had no such effect prior to enrichment on the mAb 473HD matrix. Based on these findings we conclude that the DSD-1 epitope by itself is sufficient to promote neurite outgrowth and that this activity is possibly associated with D motifs.
Department of Neurobiology, University of Heidelberg, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany.
A M
AM
Clement
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S
Nadanaka
K
K
Masayama
C
C
Mandl
K
K
Sugahara
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Faissner
D000818:Animals; D000943:Antigens, Differentiation; D002531:Cerebellum / Q000166:cytology / Q000196:embryology; D011508:Chondroitin Sulfate Proteoglycans / Q000276:immunology / Q000494:pharmacology*; D002846:Chromatography, Affinity; D000939:Epitopes; D006025:Glycosaminoglycans / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000196:embryology; D009414:Nerve Growth Factors / Q000276:immunology / Q000494:pharmacology*; D009420:Nervous System / Q000276:immunology; D016501:Neurites / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013463:Sulfuric Acid Esters / Q000276:immunology / Q000494:pharmacology*
D000943:Antigens, Differentiation; D011508:Chondroitin Sulfate Proteoglycans; D000939:Epitopes; D006025:Glycosaminoglycans; D009414:Nerve Growth Factors; D013463:Sulfuric Acid Esters