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Johan Zelano

Publications and source records attributed to Johan Zelano.

9 recordsLinked to original sources
PubMed2006

Expression of nectin-1, nectin-3, N-cadherin, and NCAM in spinal motoneurons after sciatic nerve transection.

We here study the expression patterns of the cell adhesion molecules nectin-1, nectin-3, N-cadherin, and neural cell adhesion molecule (NCAM) in motoneurons after sciatic nerve transection (SNT). Nectins are a newly discovered family of adhesion molecules that colocalize with N-cadherin in synapses and are expressed in axons during development. By in situ hybridization (ISH), we found nectin-3, N-cadherin, and NCAM mRNA in uninjured motoneurons. In uninjured animals, nectin-3 mRNA was present in a few vesicular acetylcholine transporter (VAChT)-positive cells of small motoneuron size in lamina IX of the spinal cord. SNT induced a significant increase of nectin-1, nectin-3, and NCAM mRNA, but the signal for N-cadherin mRNA was not affected. After SNT, signal for nectin-3 mRNA appeared over most motoneurons. We next investigated the presence of N-cadherin and nectin protein in synapses on spinal motoneurons by immunohistochemistry. Only N-cadherin immunoreactivity was seen in close relation to synaptophysin staining, while nectin-1 and nectin-3 immunoreactivity did not display such proximity. SNT resulted in decreased immunoreactivity for N-cadherin around the motoneuron soma, while nectin-1 and nectin-3 immunoreactivity remained unchanged. In the peripheral sciatic nerve, nectin-3 immunoreactivity was observed both in controls and following injury and nectin-3 colocalized with both neurofilament and the Schwann cell marker S100. In addition, an increased ISH signal for nectin-3 mRNA could be seen over the proximal stump of the sciatic nerve after SNT. We conclude that motoneuron injury induces complex changes in the spatiotemporal expression pattern of the investigated cell adhesion molecules.

Animals↗
PubMed2004

Dorsal root ganglion neurons up-regulate the expression of laminin-associated integrins after peripheral but not central axotomy.

The favorable prognosis of regeneration in the peripheral nervous system after axonal lesions is generally regarded as dependent on the Schwann cell basal lamina. Laminins, a heterotrimeric group of basal lamina molecules, have been suggested to be among the factors playing this supportive role. For neurons to utilize laminin as a substrate for growth, an expression of laminin binding receptors, integrins, is necessary. In this study, we have examined the expression of laminin binding integrin subunits in dorsal root ganglion (DRG) neurons after transection to either their peripherally projecting axons, as in the sciatic nerve, followed by regeneration, or the centrally projecting axons in dorsal roots, followed by no or weak regenerative activity. In uninjured DRG, immunohistochemical staining revealed a few neurons expressing integrin subunit alpha6, whereas integrin subunits alpha7 and foremost beta1 were expressed in a majority of neurons. After an injury to the sciatic nerve, mRNAs encoding all three integrins were up-regulated in DRG neurons. By anterograde tracing, immunoreactivity for all studied integrins was also found in association with growing axons after a sciatic nerve crush lesion in vivo. In contrast, mRNA levels remained constant in DRG neurons after a dorsal root injury. Together with previous findings, this suggests that integrin subunits alpha6, alpha7, and beta1 have an important role in the regenerative response following nerve injury and that the lack of regenerative capacity following dorsal root injury could in part be explained by the absence of response in integrin regulation.

Animals↗