The role of proteoglycans in Schwann cell/astrocyte interactions and in regeneration failure at PNS/CNS interfaces.
In the dorsal root entry zone (DREZ) peripheral sensory axons fail to regenerate past the peripheral nervous system/central nervous system (PNS/CNS) interface. Additionally, in the spinal cord, central fibers that regenerate into Schwann cell (SC) bridges can enter but do not exit at the distal Schwann cell/astrocyte (AC) boundary. At both interfaces where limited mixing of the two cell types occurs, one can observe an up-regulation of inhibitory chondroitin sulfate proteoglycans (CSPGs). We treated confrontation Schwann cell/astrocyte cultures with the following: (1) a deoxyribonucleic acid (DNA) enzyme against the glycosaminoglycan (GAG)-chain-initiating enzyme, xylosyltransferase-1 (XT-1), (2) a control DNA enzyme, and (3) chondroitinase ABC (Ch'ase ABC) to degrade the GAG chains. Both techniques for reducing CSPGs allowed Schwann cells to penetrate deeply into the territory of the astrocytes. After adding sensory neurons to the assay, the axons showed different growth behaviors depending upon the glial cell type that they first encountered during regeneration. Our results help to explain why regeneration fails at PNS/CNS glial boundaries.
Grimpe
Barbara
B
Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
Pressman
Yelena
Y
Lupa
Michael David
MD
Horn
Kevin Paul
KP
Bunge
Mary Bartlett
MB
Silver
Jerry
J
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D002490:Central Nervous System / Q000166:cytology / Q000378:metabolism*; D019765:Chondroitin ABC Lyase / Q000494:pharmacology; D018920:Coculture Techniques; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D009416:Nerve Regeneration / Q000187:drug effects / Q000502:physiology*; D010430:Pentosyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017933:Peripheral Nervous System / Q000166:cytology / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D012583:Schwann Cells / Q000166:cytology / Q000378:metabolism*; D000097608:UDP Xylose-Protein Xylosyltransferase
D019765:Chondroitin ABC Lyase; D006025:Glycosaminoglycans; D010430:Pentosyltransferases; D011509:Proteoglycans; D000097608:UDP Xylose-Protein Xylosyltransferase