The Experts below are selected from a list of 39477 Experts worldwide ranked by ideXlab platform
Jean E Vance - One of the best experts on this subject based on the ideXlab platform.
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phosphatidylcholine biosynthesis via ctp phosphocholine cytidylyltransferase β2 facilitates Neurite outgrowth and branching
Journal of Biological Chemistry, 2008Co-Authors: Jodi M Carter, Robert B. Campenot, Jean E Vance, Dennis E Vance, Laurent DemizieuxAbstract:Hallmarks of neuronal differentiation are Neurite sprouting, extension, and branching. We previously showed that increased expression of CTP:phosphocholine cytidylyltransferase beta2 (CTbeta2), an isoform of a key phosphatidylcholine (PC) biosynthetic enzyme, accompanies Neurite outgrowth (Carter, J. M., Waite, K. A., Campenot, R. B., Vance, J. E., and Vance, D. E. (2003) J. Biol. Chem. 278, 44988-44994). CTbeta2 mRNA is highly expressed in the brain. We show that CTbeta2 is abundant in axons of rat sympathetic neurons and retinal ganglion cells. We used RNA silencing to decrease CTbeta2 expression in PC12 cells differentiated by nerve growth factor. In CTbeta2-silenced cells, numbers of primary and secondary Neurites were markedly reduced, suggesting that CTbeta2 facilitates Neurite outgrowth and branching. However, the length of individual Neurites was significantly increased, and the total amount of neuronal membrane was unchanged. Neurite branching of PC12 cells is known to be inhibited by activation of Akt and promoted by the Akt inhibitor LY294002. Our experiments showed that LY294002 increases Neurite sprouting and branching in control PC12 cells but not in CTbeta2-deficient cells. CTbeta2 was not phosphorylated in vitro by Akt. However, inhibition of Cdk5 by roscovitine blocked CTbeta2 phosphorylation and reduced Neurite outgrowth and branching. These results highlight the importance of CTbeta2 in neurons for promoting Neurite outgrowth and branching and represent the first identification of a lipid biosynthetic enzyme that facilitates these functions.
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enhanced expression and activation of ctp phosphocholine cytidylyltransferase β2 during Neurite outgrowth
Journal of Biological Chemistry, 2003Co-Authors: Robert B. Campenot, Jodi M Carter, Kristin A Waite, Jean E Vance, Dennis E VanceAbstract:During differentiation neurons increase phospholipid biosynthesis to provide new membrane for Neurite growth. We studied the regulation of phosphatidylcholine (PC) biosynthesis during differentiation of two neuronal cell lines: PC12 cells and Neuro2a cells. We hypothesized that in PC12 cells nerve growth factor (NGF) would up-regulate the activity and expression of the rate-limiting enzyme in PC biosynthesis, CTP:phosphocholine cytidylyltransferase (CT). During Neurite outgrowth, NGF doubled the amount of cellular PC and CT activity. CTbeta2 mRNA increased within 1 day of NGF application, prior to the formation of visible Neurites, and continued to increase during Neurite growth. When Neurites retracted in response to NGF withdrawal, CTbeta2 mRNA, protein, and CT activity decreased. NGF specifically activated CTbeta2 by promoting its translocation from cytosol to membranes. In contrast, NGF did not alter CTalpha expression or translocation. The increase in both CTbeta2 mRNA and CT activity was inhibited by U0126, an inhibitor of mitogen-activated kinase/extracellular signal-regulated kinase kinase 1/2 (MEK1/2). In Neuro2a cells, retinoic acid significantly increased CT activity (by 54%) and increased CTbeta2 protein, coincident with Neurite outgrowth but did not change CTalpha expression. Together, these data suggest that the CTbeta2 isoform of CT is specifically up-regulated and activated during neuronal differentiation to increase PC biosynthesis for growing Neurites.
Dennis E Vance - One of the best experts on this subject based on the ideXlab platform.
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phosphatidylcholine biosynthesis via ctp phosphocholine cytidylyltransferase β2 facilitates Neurite outgrowth and branching
Journal of Biological Chemistry, 2008Co-Authors: Jodi M Carter, Robert B. Campenot, Jean E Vance, Dennis E Vance, Laurent DemizieuxAbstract:Hallmarks of neuronal differentiation are Neurite sprouting, extension, and branching. We previously showed that increased expression of CTP:phosphocholine cytidylyltransferase beta2 (CTbeta2), an isoform of a key phosphatidylcholine (PC) biosynthetic enzyme, accompanies Neurite outgrowth (Carter, J. M., Waite, K. A., Campenot, R. B., Vance, J. E., and Vance, D. E. (2003) J. Biol. Chem. 278, 44988-44994). CTbeta2 mRNA is highly expressed in the brain. We show that CTbeta2 is abundant in axons of rat sympathetic neurons and retinal ganglion cells. We used RNA silencing to decrease CTbeta2 expression in PC12 cells differentiated by nerve growth factor. In CTbeta2-silenced cells, numbers of primary and secondary Neurites were markedly reduced, suggesting that CTbeta2 facilitates Neurite outgrowth and branching. However, the length of individual Neurites was significantly increased, and the total amount of neuronal membrane was unchanged. Neurite branching of PC12 cells is known to be inhibited by activation of Akt and promoted by the Akt inhibitor LY294002. Our experiments showed that LY294002 increases Neurite sprouting and branching in control PC12 cells but not in CTbeta2-deficient cells. CTbeta2 was not phosphorylated in vitro by Akt. However, inhibition of Cdk5 by roscovitine blocked CTbeta2 phosphorylation and reduced Neurite outgrowth and branching. These results highlight the importance of CTbeta2 in neurons for promoting Neurite outgrowth and branching and represent the first identification of a lipid biosynthetic enzyme that facilitates these functions.
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enhanced expression and activation of ctp phosphocholine cytidylyltransferase β2 during Neurite outgrowth
Journal of Biological Chemistry, 2003Co-Authors: Robert B. Campenot, Jodi M Carter, Kristin A Waite, Jean E Vance, Dennis E VanceAbstract:During differentiation neurons increase phospholipid biosynthesis to provide new membrane for Neurite growth. We studied the regulation of phosphatidylcholine (PC) biosynthesis during differentiation of two neuronal cell lines: PC12 cells and Neuro2a cells. We hypothesized that in PC12 cells nerve growth factor (NGF) would up-regulate the activity and expression of the rate-limiting enzyme in PC biosynthesis, CTP:phosphocholine cytidylyltransferase (CT). During Neurite outgrowth, NGF doubled the amount of cellular PC and CT activity. CTbeta2 mRNA increased within 1 day of NGF application, prior to the formation of visible Neurites, and continued to increase during Neurite growth. When Neurites retracted in response to NGF withdrawal, CTbeta2 mRNA, protein, and CT activity decreased. NGF specifically activated CTbeta2 by promoting its translocation from cytosol to membranes. In contrast, NGF did not alter CTalpha expression or translocation. The increase in both CTbeta2 mRNA and CT activity was inhibited by U0126, an inhibitor of mitogen-activated kinase/extracellular signal-regulated kinase kinase 1/2 (MEK1/2). In Neuro2a cells, retinoic acid significantly increased CT activity (by 54%) and increased CTbeta2 protein, coincident with Neurite outgrowth but did not change CTalpha expression. Together, these data suggest that the CTbeta2 isoform of CT is specifically up-regulated and activated during neuronal differentiation to increase PC biosynthesis for growing Neurites.
Richard J Mcmurtrey - One of the best experts on this subject based on the ideXlab platform.
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patterned and functionalized nanofiber scaffolds in three dimensional hydrogel constructs enhance Neurite outgrowth and directional control
arXiv: Tissues and Organs, 2015Co-Authors: Richard J McmurtreyAbstract:Neural tissue engineering holds incredible potential to restore functional capabilities to damaged neural tissue. It was hypothesized that patterned and functionalized nanofiber scaffolds could control Neurite direction and enhance Neurite outgrowth. Aligned nanofibers were created according to a mathematical model and were shown to enable significant control over the direction of Neurite outgrowth in both two-dimensional (2D) and three-dimensional (3D) neuronal cultures. Laminin-functionalized nanofibers in 3D hyaluronic acid (HA) hydrogels enabled significant alignment of Neurites with nanofibers, enabled significant Neurite tracking of nanofibers, and significantly increased the distance over which Neurites could extend. This work demonstrates the ability to create unique 3D neural tissue constructs using a combined system of hydrogel and nanofiber scaffolding. Importantly, patterned and biofunctionalized nanofiber scaffolds that can control direction and increase length of Neurite outgrowth in three-dimensions hold much potential for neural tissue engineering. This approach offers advancements in the development of implantable neural tissue constructs that enable control of neural development and reproduction of neuroanatomical pathways, with the ultimate goal being the achievement of functional neural regeneration.
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Patterned and functionalized nanofiber scaffolds in three-dimensional hydrogel constructs enhance Neurite outgrowth and directional control
Journal of Neural Engineering, 2014Co-Authors: Richard J McmurtreyAbstract:Objective. Neural tissue engineering holds incredible potential to restore functional capabilities to damaged neural tissue. It was hypothesized that patterned and functionalized nanofiber scaffolds could control Neurite direction and enhance Neurite outgrowth. Approach. A method of creating aligned electrospun nanofibers was implemented and fiber characteristics were analyzed using environmental scanning electron microscopy. Nanofibers were composed of polycaprolactone (PCL) polymer, PCL mixed with gelatin, or PCL with a laminin coating. Three-dimensional hydrogels were then integrated with embedded aligned nanofibers to support neuronal cell cultures. Microscopic images were captured at high-resolution in single and multi-focal planes with eGFP-expressing neuronal SH-SY5Y cells in a fluorescent channel and nanofiber scaffolding in another channel. Neuronal morphology and Neurite tracking of nanofibers were then analyzed in detail. Main results. Aligned nanofibers were shown to enable significant control over the direction of Neurite outgrowth in both two-dimensional (2D) and three-dimensional (3D) neuronal cultures. Laminin-functionalized nanofibers in 3D hyaluronic acid (HA) hydrogels enabled significant alignment of Neurites with nanofibers, enabled significant Neurite tracking of nanofibers, and significantly increased the distance over which Neurites could extend. Specifically, the average length of Neurites per cell in 3D HA constructs with laminin-functionalized nanofibers increased by 66% compared to the same laminin fibers on 2D laminin surfaces, increased by 59% compared to 2D laminin-coated surface without fibers, and increased by 1052% compared to HA constructs without fibers. Laminin functionalization of fibers also doubled average Neurite length over plain PCL fibers in the same 3D HA constructs. In addition, Neurites also demonstrated tracking directly along the fibers, with 66% of Neurite lengths directly tracking laminin-coated fibers in 3D HA constructs, which was a 65% relative increase in Neurite tracking compared to plain PCL fibers in the same 3D HA constructs and a 213% relative increase over laminin-coated fibers on 2D laminin-coated surfaces. Significance. This work demonstrates the ability to create unique 3D neural tissue constructs using a combined system of hydrogel and nanofiber scaffolding. Importantly, patterned and biofunctionalized nanofiber scaffolds that can control direction and increase length of Neurite outgrowth in three-dimensions hold much potential for neural tissue engineering. This approach offers advancements in the development of implantable neural tissue constructs that enable control of neural development and reproduction of neuroanatomical pathways, with the ultimate goal being the achievement of functional neural regeneration.
Jodi M Carter - One of the best experts on this subject based on the ideXlab platform.
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phosphatidylcholine biosynthesis via ctp phosphocholine cytidylyltransferase β2 facilitates Neurite outgrowth and branching
Journal of Biological Chemistry, 2008Co-Authors: Jodi M Carter, Robert B. Campenot, Jean E Vance, Dennis E Vance, Laurent DemizieuxAbstract:Hallmarks of neuronal differentiation are Neurite sprouting, extension, and branching. We previously showed that increased expression of CTP:phosphocholine cytidylyltransferase beta2 (CTbeta2), an isoform of a key phosphatidylcholine (PC) biosynthetic enzyme, accompanies Neurite outgrowth (Carter, J. M., Waite, K. A., Campenot, R. B., Vance, J. E., and Vance, D. E. (2003) J. Biol. Chem. 278, 44988-44994). CTbeta2 mRNA is highly expressed in the brain. We show that CTbeta2 is abundant in axons of rat sympathetic neurons and retinal ganglion cells. We used RNA silencing to decrease CTbeta2 expression in PC12 cells differentiated by nerve growth factor. In CTbeta2-silenced cells, numbers of primary and secondary Neurites were markedly reduced, suggesting that CTbeta2 facilitates Neurite outgrowth and branching. However, the length of individual Neurites was significantly increased, and the total amount of neuronal membrane was unchanged. Neurite branching of PC12 cells is known to be inhibited by activation of Akt and promoted by the Akt inhibitor LY294002. Our experiments showed that LY294002 increases Neurite sprouting and branching in control PC12 cells but not in CTbeta2-deficient cells. CTbeta2 was not phosphorylated in vitro by Akt. However, inhibition of Cdk5 by roscovitine blocked CTbeta2 phosphorylation and reduced Neurite outgrowth and branching. These results highlight the importance of CTbeta2 in neurons for promoting Neurite outgrowth and branching and represent the first identification of a lipid biosynthetic enzyme that facilitates these functions.
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enhanced expression and activation of ctp phosphocholine cytidylyltransferase β2 during Neurite outgrowth
Journal of Biological Chemistry, 2003Co-Authors: Robert B. Campenot, Jodi M Carter, Kristin A Waite, Jean E Vance, Dennis E VanceAbstract:During differentiation neurons increase phospholipid biosynthesis to provide new membrane for Neurite growth. We studied the regulation of phosphatidylcholine (PC) biosynthesis during differentiation of two neuronal cell lines: PC12 cells and Neuro2a cells. We hypothesized that in PC12 cells nerve growth factor (NGF) would up-regulate the activity and expression of the rate-limiting enzyme in PC biosynthesis, CTP:phosphocholine cytidylyltransferase (CT). During Neurite outgrowth, NGF doubled the amount of cellular PC and CT activity. CTbeta2 mRNA increased within 1 day of NGF application, prior to the formation of visible Neurites, and continued to increase during Neurite growth. When Neurites retracted in response to NGF withdrawal, CTbeta2 mRNA, protein, and CT activity decreased. NGF specifically activated CTbeta2 by promoting its translocation from cytosol to membranes. In contrast, NGF did not alter CTalpha expression or translocation. The increase in both CTbeta2 mRNA and CT activity was inhibited by U0126, an inhibitor of mitogen-activated kinase/extracellular signal-regulated kinase kinase 1/2 (MEK1/2). In Neuro2a cells, retinoic acid significantly increased CT activity (by 54%) and increased CTbeta2 protein, coincident with Neurite outgrowth but did not change CTalpha expression. Together, these data suggest that the CTbeta2 isoform of CT is specifically up-regulated and activated during neuronal differentiation to increase PC biosynthesis for growing Neurites.
Marlan R Hansen - One of the best experts on this subject based on the ideXlab platform.
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photopolymerized microfeatures guide adult spiral ganglion and dorsal root ganglion Neurite growth
Otology & Neurotology, 2018Co-Authors: Alison E Seline, Allan C Guymon, Braden Leigh, Mark Ramirez, Marlan R HansenAbstract:HYPOTHESIS Microtopographical patterns generated by photopolymerization of methacrylate polymer systems will direct growth of Neurites from adult neurons, including spiral ganglion neurons (SGNs). BACKGROUND Cochlear implants (CIs) provide hearing perception to patients with severe to profound hearing loss. However, their ability to encode complex auditory stimuli is limited due, in part, to poor spatial resolution caused by spread of the electrical currents in the inner ear. Directing the regrowth of SGN peripheral processes towards stimulating electrodes could help reduce current spread and improve spatial resolution provided by the CI. Previous work has demonstrated that micro- and nano-scale patterned surfaces precisely guide the growth of Neurites from a variety of neonatal neurons including SGNs. Here, we sought to determine the extent to which adult neurons likewise respond to these topographical surface features. METHODS Photopolymerization was used to fabricate methacrylate polymer substrates with micropatterned surfaces of varying amplitudes and periodicities. Dissociated adult dorsal root ganglion neurons (DRGNs) and SGNs were cultured on these surfaces and the alignment of the Neurite processes to the micropatterns was determined. RESULTS Neurites from both adult DRGNs and SGNs significantly aligned to the patterned surfaces similar to their neonatal counterparts. Further DRGN and SGN Neurite alignment increased as the amplitude of the microfeatures increased. Decreased pattern periodicity also improved Neurite alignment. CONCLUSION Microscale surface topographic features direct the growth of adult SGN Neurites. Topographical features could prove useful for guiding growth of SGN peripheral axons towards a CI electrode array.
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micropatterned methacrylate polymers direct spiral ganglion Neurite and schwann cell growth
Hearing Research, 2011Co-Authors: Joseph C Clarke, Allan C Guymon, Bradley W Tuft, John D Clinger, Rachel Levine, Lucas Sievens Figueroa, Marlan R HansenAbstract:Abstract Significant advances in the functional outcomes achieved with cochlear implantation will likely require tissue-engineering approaches to improve the neural prosthesis interface. One strategy is to direct spiral ganglion neuron (SGN) axon growth in a highly organized fashion to approximate or contact stimulating electrodes. Here we assessed the ability of micropatterns induced by photopolymerization in methacrylate (MA) polymer systems to direct cultured neonatal rat SGN Neurite growth and alignment of SG Schwann cells (SGSCs). SGN survival and Neurite length were comparable among various polymer compositions. Remarkably, there was no significant difference in SGN survival or Neurite length between laminin and non-laminin coated MA polymer substrates, suggesting high biocompatibility with SG tissue. Micropatterning with photopolymerization generated microchannels with a ridge periodicity of 50 μm and channel depths of 0.6–1.0 μm. SGN Neurites grew within the grooves of the microchannels. These topographies strongly induced alignment of dissociated SGN Neurites and SGSCs to parallel the pattern. By contrast, fibroblasts failed to align with the micropattern suggesting cell specific responses to topographical cues. SGN Neurites extending from explants turned to parallel the pattern as they encountered the microchannels. The extent of turning was significantly correlated with angle at which the Neurite initially encountered the pattern. These results indicate that SGN Neurites respond to microtopographical features and that these features can be used to direct Neurite growth in a highly organized fashion.
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membrane depolarization inhibits spiral ganglion Neurite growth via activation of multiple types of voltage sensitive calcium channels and calpain
Molecular and Cellular Neuroscience, 2008Co-Authors: Pamela C Roehm, Erika A Woodson, Steven H Green, Marlan R HansenAbstract:Abstract The effect of membrane electrical activity on spiral ganglion neuron (SGN) Neurite growth remains unknown despite its relevance to cochlear implant technology. We demonstrate that membrane depolarization delays the initial formation and inhibits the subsequent extension of cultured SGN Neurites. This inhibition depends directly on the level of depolarization with higher levels of depolarization causing retraction of existing Neurites. Cultured SGNs express subunits for L-type, N-type, and P/Q type voltage-gated calcium channels (VGCCs) and removal of extracellular Ca 2+ or treatment with a combination of L-type, N-type, and P/Q-type VGCC antagonists rescues SGN Neurite growth under depolarizing conditions. By measuring the fluorescence intensity of SGNs loaded with the fluorogenic calpain substrate t -butoxy carbonyl-Leu-Met-chloromethylaminocoumarin (20 μM), we demonstrate that depolarization activates calpains. Calpeptin (15 μM), a calpain inhibitor, prevents calpain activation by depolarization and rescues Neurite growth in depolarized SGNs suggesting that calpain activation contributes to the inhibition of Neurite growth by depolarization.
