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Peripheral nervous system genes expressed in central neurons induce growth on inhibitory substrates.

Buchser WJ, Smith RP, Pardinas JR, Haddox CL, Hutson T, Moon L, Hoffman SR, Bixby JL, Lemmon VP - PLoS ONE (2012)

Bottom Line: Peripheral nervous system (PNS) neurons exhibit increased regenerative ability compared to central nervous system neurons, even in the presence of inhibitory environments.Several known growth associated proteins potentiated neurite growth on laminin.Bioinformatic approaches also uncovered a number of novel gene families that altered neurite growth of CNS neurons.

View Article: PubMed Central - PubMed

Affiliation: Miami Project to Cure Paralysis, Department of Pharmacology, University of Miami, Miller School of Medicine, Miami, Florida, United States of America.

ABSTRACT
Trauma to the spinal cord and brain can result in irreparable loss of function. This failure of recovery is in part due to inhibition of axon regeneration by myelin and chondroitin sulfate proteoglycans (CSPGs). Peripheral nervous system (PNS) neurons exhibit increased regenerative ability compared to central nervous system neurons, even in the presence of inhibitory environments. Previously, we identified over a thousand genes differentially expressed in PNS neurons relative to CNS neurons. These genes represent intrinsic differences that may account for the PNS's enhanced regenerative ability. Cerebellar neurons were transfected with cDNAs for each of these PNS genes to assess their ability to enhance neurite growth on inhibitory (CSPG) or permissive (laminin) substrates. Using high content analysis, we evaluated the phenotypic profile of each neuron to extract meaningful data for over 1100 genes. Several known growth associated proteins potentiated neurite growth on laminin. Most interestingly, novel genes were identified that promoted neurite growth on CSPGs (GPX3, EIF2B5, RBMX). Bioinformatic approaches also uncovered a number of novel gene families that altered neurite growth of CNS neurons.

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GPX3 and GPX7 significantly increase neurite length of postnatal CGNs plated on the inhibitory MAG substrate.Postnatal day 8 rat CGNs were co-transfected with the pmaxGFP plasmid (green) and the pCMVSPORT6 plasmid expressing either GPX3, GPX7, OGFLR1 or the control gene mCherry and plated onto a feeder layer of CHO cells expressing a non-inhibitory construct (R2), or the CNS myelin component, MAG. A. CGNs growing on CHO-R2 transfected with GFP and mCherry. B. CHO-MAG strongly inhibited the neurite outgrowth of CGNs transfected with GFP and mCherry. C. CGN neurite outgrowth is partially rescued when transfected with GPX3. D. Data are plotted as mean +/− SEM of 8 experiments, (One-way ANOVA, Dunnett’s post hoc, *p<0.05, ***p<0.001). Red channel marks β-tubulin positive neurons, green channel represents GFP expression, transfected neurons therefore appear yellow.
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pone-0038101-g005: GPX3 and GPX7 significantly increase neurite length of postnatal CGNs plated on the inhibitory MAG substrate.Postnatal day 8 rat CGNs were co-transfected with the pmaxGFP plasmid (green) and the pCMVSPORT6 plasmid expressing either GPX3, GPX7, OGFLR1 or the control gene mCherry and plated onto a feeder layer of CHO cells expressing a non-inhibitory construct (R2), or the CNS myelin component, MAG. A. CGNs growing on CHO-R2 transfected with GFP and mCherry. B. CHO-MAG strongly inhibited the neurite outgrowth of CGNs transfected with GFP and mCherry. C. CGN neurite outgrowth is partially rescued when transfected with GPX3. D. Data are plotted as mean +/− SEM of 8 experiments, (One-way ANOVA, Dunnett’s post hoc, *p<0.05, ***p<0.001). Red channel marks β-tubulin positive neurons, green channel represents GFP expression, transfected neurons therefore appear yellow.

Mentions: In addition to CSPGs, we showed that CGNs cultured on CHO cells expressing the myelin protein Myelin Associated Glycoprotein (MAG), had shorter neurite lengths (Fig. 5B) than CGNs growing on CHO cells expressing a control protein R2 (Fig. 5A). When GPX3 (Fig. 5C), GPX7 or OGFLR1 were transfected into the CGNs, they were able to overcome the growth inhibition of MAG (Fig. 5D), to a similar level as a positive control, the ROCK inhibitor Y-27632 (One-way ANOVA, Dunnett’s post hoc, n = 8). Thus, although the plasmids for GPX3 and OGFRL1 were identified in a screen using inhibitory CSPGs, they effectively enhanced neurite growth on another CNS inhibitory substrate, MAG.


Peripheral nervous system genes expressed in central neurons induce growth on inhibitory substrates.

Buchser WJ, Smith RP, Pardinas JR, Haddox CL, Hutson T, Moon L, Hoffman SR, Bixby JL, Lemmon VP - PLoS ONE (2012)

GPX3 and GPX7 significantly increase neurite length of postnatal CGNs plated on the inhibitory MAG substrate.Postnatal day 8 rat CGNs were co-transfected with the pmaxGFP plasmid (green) and the pCMVSPORT6 plasmid expressing either GPX3, GPX7, OGFLR1 or the control gene mCherry and plated onto a feeder layer of CHO cells expressing a non-inhibitory construct (R2), or the CNS myelin component, MAG. A. CGNs growing on CHO-R2 transfected with GFP and mCherry. B. CHO-MAG strongly inhibited the neurite outgrowth of CGNs transfected with GFP and mCherry. C. CGN neurite outgrowth is partially rescued when transfected with GPX3. D. Data are plotted as mean +/− SEM of 8 experiments, (One-way ANOVA, Dunnett’s post hoc, *p<0.05, ***p<0.001). Red channel marks β-tubulin positive neurons, green channel represents GFP expression, transfected neurons therefore appear yellow.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3368946&req=5

pone-0038101-g005: GPX3 and GPX7 significantly increase neurite length of postnatal CGNs plated on the inhibitory MAG substrate.Postnatal day 8 rat CGNs were co-transfected with the pmaxGFP plasmid (green) and the pCMVSPORT6 plasmid expressing either GPX3, GPX7, OGFLR1 or the control gene mCherry and plated onto a feeder layer of CHO cells expressing a non-inhibitory construct (R2), or the CNS myelin component, MAG. A. CGNs growing on CHO-R2 transfected with GFP and mCherry. B. CHO-MAG strongly inhibited the neurite outgrowth of CGNs transfected with GFP and mCherry. C. CGN neurite outgrowth is partially rescued when transfected with GPX3. D. Data are plotted as mean +/− SEM of 8 experiments, (One-way ANOVA, Dunnett’s post hoc, *p<0.05, ***p<0.001). Red channel marks β-tubulin positive neurons, green channel represents GFP expression, transfected neurons therefore appear yellow.
Mentions: In addition to CSPGs, we showed that CGNs cultured on CHO cells expressing the myelin protein Myelin Associated Glycoprotein (MAG), had shorter neurite lengths (Fig. 5B) than CGNs growing on CHO cells expressing a control protein R2 (Fig. 5A). When GPX3 (Fig. 5C), GPX7 or OGFLR1 were transfected into the CGNs, they were able to overcome the growth inhibition of MAG (Fig. 5D), to a similar level as a positive control, the ROCK inhibitor Y-27632 (One-way ANOVA, Dunnett’s post hoc, n = 8). Thus, although the plasmids for GPX3 and OGFRL1 were identified in a screen using inhibitory CSPGs, they effectively enhanced neurite growth on another CNS inhibitory substrate, MAG.

Bottom Line: Peripheral nervous system (PNS) neurons exhibit increased regenerative ability compared to central nervous system neurons, even in the presence of inhibitory environments.Several known growth associated proteins potentiated neurite growth on laminin.Bioinformatic approaches also uncovered a number of novel gene families that altered neurite growth of CNS neurons.

View Article: PubMed Central - PubMed

Affiliation: Miami Project to Cure Paralysis, Department of Pharmacology, University of Miami, Miller School of Medicine, Miami, Florida, United States of America.

ABSTRACT
Trauma to the spinal cord and brain can result in irreparable loss of function. This failure of recovery is in part due to inhibition of axon regeneration by myelin and chondroitin sulfate proteoglycans (CSPGs). Peripheral nervous system (PNS) neurons exhibit increased regenerative ability compared to central nervous system neurons, even in the presence of inhibitory environments. Previously, we identified over a thousand genes differentially expressed in PNS neurons relative to CNS neurons. These genes represent intrinsic differences that may account for the PNS's enhanced regenerative ability. Cerebellar neurons were transfected with cDNAs for each of these PNS genes to assess their ability to enhance neurite growth on inhibitory (CSPG) or permissive (laminin) substrates. Using high content analysis, we evaluated the phenotypic profile of each neuron to extract meaningful data for over 1100 genes. Several known growth associated proteins potentiated neurite growth on laminin. Most interestingly, novel genes were identified that promoted neurite growth on CSPGs (GPX3, EIF2B5, RBMX). Bioinformatic approaches also uncovered a number of novel gene families that altered neurite growth of CNS neurons.

Show MeSH
Related in: MedlinePlus