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Conference Paper: Chondroitin sulfates enriched in the developing rat hindbrain restrict commissural projections of vestibular neurons

TitleChondroitin sulfates enriched in the developing rat hindbrain restrict commissural projections of vestibular neurons
Authors
Issue Date2006
PublisherS Karger AG. The Journal's web site is located at http://www.karger.com/NSG
Citation
The Hong Kong Society of Neurosciences 24th Annual Scientific Meeting, Hong Kong, 13-14 January 2005. In Neurosignals, 2006, v. 15 n. 3, p. 123 How to Cite?
AbstractIn vitro studies have shown that chondroitin sulfate proteoglycans are inhibitory to axon outgrowth and constitute barriers to pathfinding axons. To assess if chondroitin sulfates (CSs) are involved in limiting axonal projections in the early embryonic hindbrain, chondroitinase ABC was delivered into the 4th ventricles of rat embryos (E11.5–E13.5) in culture (24 h, 37 ° C) to digest away CS moieties in the nearby hindbrain matrix. Controls were treated instead with the PBS-vehicle or the heat-inactivated enzyme. The resulting commissural projections after the treatments were mapped with DiI which was introduced into the vestibular nuclear complex (VNC) near the VIIIth cranial nerve entry zone. At E11.5 (+1DIV) , ^ 5 neurites could be traced extending half of the way towards the midline. With the removal of CSs, a robust outgrowth of axons extended more than half of the way towards the midline. This suggests that CSs limit axonal outgrowth in early embryos. At E12.5 (+1 DIV) , the commissural projections assumed fascicles that reached the midline in the controls. In the enzyme-treated embryos, the axons however were unfasciculated as they extended normal to the midline. This suggested that CSs are important in limiting and guiding the course of these pioneering axons. By E13.5 (+1 DIV) , enzyme treatment apparently did not affect the pioneer axons that had advanced as thick fascicles normal to the midline. However, later axonal projections from the VNC that took place after the injection of enzyme were defasciculated as they traversed the enzyme-treated matrix. They were diverted from the course of the pioneers at various angles and positions when crossing the midline. This suggests that CSs also limit the course of the later projections which otherwise would be attracted to alternative targets. Recovery of proteoglycans from the early hindbrain and analysis of the CS components found enrichment in 6-sulfated isoforms of chondroitin as early as E11.5. These results provide in vivo evidence for possible contributions of 6-sulfated chondroitins to limit stray outgrowth and foster axonal fasciculation as vestibular neurons project across the midline towards the contralateral target.
Persistent Identifierhttp://hdl.handle.net/10722/96492
ISSN
2015 Impact Factor: 1.593
2015 SCImago Journal Rankings: 0.763

 

DC FieldValueLanguage
dc.contributor.authorKwok, JCFen_HK
dc.contributor.authorLau, JWKen_HK
dc.contributor.authorNg, KYen_HK
dc.contributor.authorShum, DKYen_HK
dc.contributor.authorChan, YSen_HK
dc.date.accessioned2010-09-25T16:35:30Z-
dc.date.available2010-09-25T16:35:30Z-
dc.date.issued2006en_HK
dc.identifier.citationThe Hong Kong Society of Neurosciences 24th Annual Scientific Meeting, Hong Kong, 13-14 January 2005. In Neurosignals, 2006, v. 15 n. 3, p. 123en_HK
dc.identifier.issn1424-862Xen_HK
dc.identifier.urihttp://hdl.handle.net/10722/96492-
dc.description.abstractIn vitro studies have shown that chondroitin sulfate proteoglycans are inhibitory to axon outgrowth and constitute barriers to pathfinding axons. To assess if chondroitin sulfates (CSs) are involved in limiting axonal projections in the early embryonic hindbrain, chondroitinase ABC was delivered into the 4th ventricles of rat embryos (E11.5–E13.5) in culture (24 h, 37 ° C) to digest away CS moieties in the nearby hindbrain matrix. Controls were treated instead with the PBS-vehicle or the heat-inactivated enzyme. The resulting commissural projections after the treatments were mapped with DiI which was introduced into the vestibular nuclear complex (VNC) near the VIIIth cranial nerve entry zone. At E11.5 (+1DIV) , ^ 5 neurites could be traced extending half of the way towards the midline. With the removal of CSs, a robust outgrowth of axons extended more than half of the way towards the midline. This suggests that CSs limit axonal outgrowth in early embryos. At E12.5 (+1 DIV) , the commissural projections assumed fascicles that reached the midline in the controls. In the enzyme-treated embryos, the axons however were unfasciculated as they extended normal to the midline. This suggested that CSs are important in limiting and guiding the course of these pioneering axons. By E13.5 (+1 DIV) , enzyme treatment apparently did not affect the pioneer axons that had advanced as thick fascicles normal to the midline. However, later axonal projections from the VNC that took place after the injection of enzyme were defasciculated as they traversed the enzyme-treated matrix. They were diverted from the course of the pioneers at various angles and positions when crossing the midline. This suggests that CSs also limit the course of the later projections which otherwise would be attracted to alternative targets. Recovery of proteoglycans from the early hindbrain and analysis of the CS components found enrichment in 6-sulfated isoforms of chondroitin as early as E11.5. These results provide in vivo evidence for possible contributions of 6-sulfated chondroitins to limit stray outgrowth and foster axonal fasciculation as vestibular neurons project across the midline towards the contralateral target.-
dc.languageengen_HK
dc.publisherS Karger AG. The Journal's web site is located at http://www.karger.com/NSGen_HK
dc.relation.ispartofNeurosignalsen_HK
dc.rightsNeurosignals. Copyright © S Karger AG.en_HK
dc.titleChondroitin sulfates enriched in the developing rat hindbrain restrict commissural projections of vestibular neuronsen_HK
dc.typeConference_Paperen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1424-862X&volume=15&spage=123&epage=123&date=2006&atitle=Chondroitin+sulfates+enriched+in+the+developing+rat+hindbrain+restrict+commissural+projections+of+vestibular+neuronsen_HK
dc.identifier.emailKwok, JCF: h9600218@hkusua.hku.hken_HK
dc.identifier.emailLau, JWK: jaegerlau@yahoo.com.hken_HK
dc.identifier.emailShum, DKY: shumdkhk@hkucc.hku.hken_HK
dc.identifier.emailChan, YS: yschan@hkucc.hku.hken_HK
dc.identifier.authorityShum, DKY=rp00321en_HK
dc.identifier.authorityChan, YS=rp00318en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1159/000095356-
dc.identifier.hkuros129727en_HK
dc.identifier.volume15en_HK
dc.identifier.spage123en_HK
dc.identifier.epage123en_HK

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