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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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Significant morphological changes after peripheral gene expression in CGNs.A, Vector grid of 154 genes from the screen, measuring neurite initiation on CSPG (vector points upward if growth was increased, downward if decreased) and laminin (vector points rightward if increased, leftward if decreased). Scale is the same for all genes and is indicated at the bottom corners (H6PD, DCTN2) and at the top right for the positive control Gö6976 (reported in Z-scores). White arrows: genes that significantly perturbed neurite initiation on both substrates, gray arrows significantly changed only on laminin, and black on CSPGs. Black dashed line separates CSPG effects between increase and decrease while gray dashed lines separates laminin effects. B–E, representative images of neurons growing on CSPG (upper panels) and laminin substrates (lower panels). Neurons expressing the gene WD repeat domain 33 (WDR33) had increased neurite initiation when grown on CSPGs but decreased neurite initiation when grown on laminin (B), while DUS3L “dihydrouridine synthase 3-like” acted as the strongest inhibitor of neurite initiation on both substrates (C). SEPT8 “Septin 8” increased neurite initiation on both substrates (D), and dynactin 2 (DCTN2) potentiated neurite initiation on laminin but not on CSPGs (E). Scale bar 200 µm.
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pone-0038101-g002: Significant morphological changes after peripheral gene expression in CGNs.A, Vector grid of 154 genes from the screen, measuring neurite initiation on CSPG (vector points upward if growth was increased, downward if decreased) and laminin (vector points rightward if increased, leftward if decreased). Scale is the same for all genes and is indicated at the bottom corners (H6PD, DCTN2) and at the top right for the positive control Gö6976 (reported in Z-scores). White arrows: genes that significantly perturbed neurite initiation on both substrates, gray arrows significantly changed only on laminin, and black on CSPGs. Black dashed line separates CSPG effects between increase and decrease while gray dashed lines separates laminin effects. B–E, representative images of neurons growing on CSPG (upper panels) and laminin substrates (lower panels). Neurons expressing the gene WD repeat domain 33 (WDR33) had increased neurite initiation when grown on CSPGs but decreased neurite initiation when grown on laminin (B), while DUS3L “dihydrouridine synthase 3-like” acted as the strongest inhibitor of neurite initiation on both substrates (C). SEPT8 “Septin 8” increased neurite initiation on both substrates (D), and dynactin 2 (DCTN2) potentiated neurite initiation on laminin but not on CSPGs (E). Scale bar 200 µm.

Mentions: As an overview, 154 of the 832 non-redundant genes that had a significant effect on neurite initiation were arranged in a grid with vectors indicating the magnitude and direction of effects on CSPGs and laminin (Fig. 2A). The grid was constructed so that genes were ordered according to the strength of their phenotype (CSPG effects along the y-axis and laminin on the x-axis). The positive control Gö6976 was near the upper right corner (activating neurite initiation on both CSPG and laminin). 31 genes increased neurite initiation on CSPGs but not on laminin, 23 increased on laminin alone, 25 decreased on laminin and 45 decreased on CSPGs. A few genes perturbed growth on both substrates, including 15 activators and 14 inhibitors. One gene, WDR33, potentiated neurites on CSPGs and inhibited on laminin. Images of neurite growth on CSPGs are shown for neurons expressing WD repeat containing gene (WDR33, Fig 2B); dihydrouridine synthase 3-like gene (DUS3L, Fig 2C), which strongly inhibited neurite growth on both substrates; Septin 8 (SEPT8, Fig 2D), which increased growth on both substrates; and Dynactin 2 (DCTN2, Fig 2E), which potentiated neurite initiation on laminin while having little or no effect on CSPGs.


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)

Significant morphological changes after peripheral gene expression in CGNs.A, Vector grid of 154 genes from the screen, measuring neurite initiation on CSPG (vector points upward if growth was increased, downward if decreased) and laminin (vector points rightward if increased, leftward if decreased). Scale is the same for all genes and is indicated at the bottom corners (H6PD, DCTN2) and at the top right for the positive control Gö6976 (reported in Z-scores). White arrows: genes that significantly perturbed neurite initiation on both substrates, gray arrows significantly changed only on laminin, and black on CSPGs. Black dashed line separates CSPG effects between increase and decrease while gray dashed lines separates laminin effects. B–E, representative images of neurons growing on CSPG (upper panels) and laminin substrates (lower panels). Neurons expressing the gene WD repeat domain 33 (WDR33) had increased neurite initiation when grown on CSPGs but decreased neurite initiation when grown on laminin (B), while DUS3L “dihydrouridine synthase 3-like” acted as the strongest inhibitor of neurite initiation on both substrates (C). SEPT8 “Septin 8” increased neurite initiation on both substrates (D), and dynactin 2 (DCTN2) potentiated neurite initiation on laminin but not on CSPGs (E). Scale bar 200 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368946&req=5

pone-0038101-g002: Significant morphological changes after peripheral gene expression in CGNs.A, Vector grid of 154 genes from the screen, measuring neurite initiation on CSPG (vector points upward if growth was increased, downward if decreased) and laminin (vector points rightward if increased, leftward if decreased). Scale is the same for all genes and is indicated at the bottom corners (H6PD, DCTN2) and at the top right for the positive control Gö6976 (reported in Z-scores). White arrows: genes that significantly perturbed neurite initiation on both substrates, gray arrows significantly changed only on laminin, and black on CSPGs. Black dashed line separates CSPG effects between increase and decrease while gray dashed lines separates laminin effects. B–E, representative images of neurons growing on CSPG (upper panels) and laminin substrates (lower panels). Neurons expressing the gene WD repeat domain 33 (WDR33) had increased neurite initiation when grown on CSPGs but decreased neurite initiation when grown on laminin (B), while DUS3L “dihydrouridine synthase 3-like” acted as the strongest inhibitor of neurite initiation on both substrates (C). SEPT8 “Septin 8” increased neurite initiation on both substrates (D), and dynactin 2 (DCTN2) potentiated neurite initiation on laminin but not on CSPGs (E). Scale bar 200 µm.
Mentions: As an overview, 154 of the 832 non-redundant genes that had a significant effect on neurite initiation were arranged in a grid with vectors indicating the magnitude and direction of effects on CSPGs and laminin (Fig. 2A). The grid was constructed so that genes were ordered according to the strength of their phenotype (CSPG effects along the y-axis and laminin on the x-axis). The positive control Gö6976 was near the upper right corner (activating neurite initiation on both CSPG and laminin). 31 genes increased neurite initiation on CSPGs but not on laminin, 23 increased on laminin alone, 25 decreased on laminin and 45 decreased on CSPGs. A few genes perturbed growth on both substrates, including 15 activators and 14 inhibitors. One gene, WDR33, potentiated neurites on CSPGs and inhibited on laminin. Images of neurite growth on CSPGs are shown for neurons expressing WD repeat containing gene (WDR33, Fig 2B); dihydrouridine synthase 3-like gene (DUS3L, Fig 2C), which strongly inhibited neurite growth on both substrates; Septin 8 (SEPT8, Fig 2D), which increased growth on both substrates; and Dynactin 2 (DCTN2, Fig 2E), which potentiated neurite initiation on laminin while having little or no effect on CSPGs.

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