Microcephaly gene Cenpj regulates axonal growth in cortical neurons through microtubule destabilization

2021 ◽  
Author(s):  
Pamela Meneses Iack ◽  
Danielle Rayêe ◽  
Roberto Lent ◽  
Victor Túlio Ribeiro‐Resende ◽  
Patrícia P. Garcez
Keyword(s):  
Cortical Neurons ◽  
Axonal Growth

scholarly journals Exosome-Mediated siRNA pool Inhibits Axonal Growth Inhibitor in Cortical Neurons of Spinal Cord Injury in Rats

2020 ◽  
Author(s):  
Qi Liao ◽  
Jiang-Hua Ming ◽  
Ge-Liang Hu
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Cell Proliferation ◽  
Cortical Neurons ◽  
Axon Growth ◽  
Axonal Growth ◽  
Growth Inhibitor ◽  
Protective Role ◽  
Primary Cortical Neurons ◽  
Cord Injury

Abstract Background: As exosomes have been confirmed as a reservoir of siRNAs involved in certain diseases, the current study aims to investigate whether exosomal-siRNA could exert a protective role in spinal cord injury (SCI). Methods and Results: Exosomes in our experiment were isolated from lysosomal membrane-associated protein 2b (Lamp2b) overexpression HEK 293T cells, and purity of exosomes was characterized by the expression of CD9, CD47, and CD63 via western blot. Furthermore, the siRNA pool contains four siRNAs including siRNA-NgR, siRNA-LINGO-1, siRNA-Troy, and siRNA-PTEN was loaded to the exosomes, which indicated a significant role for the siRNA pool in reducing the expression of axon growth inhibitory factors. Upon the completion of loading into exosomes (exo-siRNA pool), the exo-siRNA pool was injected into primary cortical neurons of the SCI model in rats before cell proliferation and Rho expression were determined With the results revealed that purified addition could be applied to future experiments. The exo-siRNA pooled transfection caused downregulation of axon growth suppressors in primary cortical neurons including Nogo receptors (NgR), leucine-rich repeats and immunoglobulin domain-containing protein 1 (LINGO-1), Troy, and phosphatase and tenson homolog (PTEN). Cell proliferation and Rho expression of primary cortical neurons inhibited the expression of axonal growth inhibitors in rats with SCI by transfecting exogenous Sirna. Conclusion: This study confirmed that exosomes derived from Lamp2b overexpression HEK 293T cells facilitated both the recovery of functions and the survival of neurons when being loaded with the siRNA pool.

scholarly journals Urokinase-type plasminogen activator (uPA) regulates the expression and function of growth-associated protein 43 (GAP-43) in the synapse

2019 ◽  
Vol 295 (2) ◽  
pp. 619-630 ◽  
Author(s):  
Paola Merino ◽  
Ariel Diaz ◽  
Enrique R. Torre ◽  
Manuel Yepes
Keyword(s):  
Plasminogen Activator ◽  
Cortical Neurons ◽  
Release Site ◽  
Axonal Growth ◽  
Presynaptic Terminals ◽  
Type Plasminogen Activator ◽  
Mature Brain ◽  
Urokinase Type Plasminogen Activator ◽  
Vesicle Cycle ◽  
And Function

Growth-associated protein 43 (GAP-43) plays a central role in the formation of presynaptic terminals, synaptic plasticity, and axonal growth and regeneration. During development, GAP-43 is found in axonal extensions of most neurons. In contrast, in the mature brain, its expression is restricted to a few presynaptic terminals and scattered axonal growth cones. Urokinase-type plasminogen activator (uPA) is a serine proteinase that, upon binding to its receptor (uPAR), catalyzes the conversion of plasminogen into plasmin and activates signaling pathways that promote cell migration, proliferation, and survival. In the developing brain, uPA induces neuritogenesis and neuronal migration. In contrast, the expression and function of uPA in the mature brain are poorly understood. However, recent evidence reveals that different forms of injury induce release of uPA and expression of uPAR in neurons and that uPA/uPAR binding triggers axonal growth and synapse formation. Here we show that binding of uPA to uPAR induces not only the mobilization of GAP-43 from the axonal shaft to the presynaptic terminal but also its activation in the axonal bouton by PKC-induced calcium-dependent phosphorylation at Ser-41 (pGAP-43). We found that this effect requires open presynaptic N-methyl-d-aspartate receptors but not plasmin generation. Furthermore, our work reveals that, following its activation by uPA/uPAR binding, pGAP-43 colocalizes with presynaptic vesicles and triggers their mobilization to the synaptic release site. Together, these data reveal a novel role of uPA as an activator of the synaptic vesicle cycle in cerebral cortical neurons via its ability to induce presynaptic recruitment and activation of GAP-43.

scholarly journals Ischemic Cerebral Endothelial Cell–Derived Exosomes Promote Axonal Growth

Stroke ◽  
2020 ◽  
Vol 51 (12) ◽  
pp. 3701-3712
Author(s):  
Yi Zhang ◽  
Yi Qin ◽  
Michael Chopp ◽  
Chao Li ◽  
Amy Kemper ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Neuronal Cell ◽  
Axonal Growth ◽  
Mature Mirnas ◽  
Bioinformatic Analysis ◽  
Axonal Outgrowth ◽  
Ischemic Brain ◽  
Neuronal Homeostasis ◽  
Neuronal Cell Bodies

Background and Purpose: Cerebral endothelial cells (CECs) and axons of neurons interact to maintain vascular and neuronal homeostasis and axonal remodeling in normal and ischemic brain, respectively. However, the role of exosomes in the interaction of CECs and axons in brain under normal conditions and after stroke is unknown. Methods: Exosomes were isolated from CECs of nonischemic rats and is chemic rats (nCEC-exos and isCEC-exos), respectively. A multicompartmental cell culture system was used to separate axons from neuronal cell bodies. Results: Axonal application of nCEC-exos promotes axonal growth of cortical neurons, whereas isCEC-exos further enhance axonal growth than nCEC-exos. Ultrastructural analysis revealed that CEC-exos applied into distal axons were internalized by axons and reached to their parent somata. Bioinformatic analysis revealed that both nCEC-exos and isCEC-exos contain abundant mature miRNAs; however, isCEC-exos exhibit more robust elevation of select miRNAs than nCEC-exos. Mechanistically, axonal application of nCEC-exos and isCEC-exos significantly elevated miRNAs and reduced proteins in distal axons and their parent somata that are involved in inhibiting axonal outgrowth. Blockage of axonal transport suppressed isCEC-exo–altered miRNAs and proteins in somata but not in distal axons. Conclusions: nCEC-exos and isCEC-exos facilitate axonal growth by altering miRNAs and their target protein profiles in recipient neurons.

Abstract WMP41: Characterization of MicroRNAs and Their Target Proteins in Distal Axons of Cortical Neurons

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Chao Li ◽  
Yi Zhang ◽  
Albert M Levin ◽  
Michael Chopp ◽  
Zheng Gang Zhang
Keyword(s):  
Cortical Neurons ◽  
Mirna Target ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Axonal Growth ◽  
Bioinformatic Analysis ◽  
Inhibitory Effect ◽  
Bioinformatic Tools ◽  
Molecular Information

Introduction: Axonal growth is essential for the establishment of a functional neuronal network. Molecular information of axon is limited. MicroRNAs (miRNAs) regulate post-transcriptional gene expression. We hypothesized that axonal miRNAs are locally relevant to their target genes. Methods: Proteins and RNAs were extracted from distal axons of cortical neurons cultured in a microfluidic device. A mass spectrometer and miRNA arrays were used to measure proteins and miRNAs, respectively. Ingenuity Pathway Analysis (IPA) and Database for Annotation, Visualization and Integrated Discovery (DAVID) bioinformatic tools were used to make in silico predictions of functionally relevant miRNA target genes. Results: Proteomic showed that distal axons contained 883 proteins. Bioinformatic analysis showed the presence of 94 proteins that regulate axonal growth. To identify relevant miRNAs to these 94 proteins, miRNAs with 8mer sites that exactly match target genes were considered, based on the fact that 8mer sites efficaciously affect miRNA-target interactions. Of the 94 genes, we found that there were 56 candidate genes that can be targeted by 62 miRNAs enriched in axons. Among them, we validated 13 proteins and 11 miRNAs, respectively, by means of Western blot and RT-PCR. To examine target genes, we treated axons with chondroitin sulfate proteoglycans (CSPGs) that inhibit axonal growth and examined alterations of these proteins and miRNAs in the distal axons. We found that elevation of miR-203a, -133b, -29abc and -92ab were associated with reduced AKT, MTOR, PI3Kp85, DPYSL2, MAP1B, PPP2CA and DCX proteins, whereas decreased miR-15b, -26b, -34b, -376b, -128, -381 and -195 were accompanied by increased proteins of EZR, KIF5A, RTN4, GSK3B, and ROCK2. Bioinformatic analysis revealed that these miRNAs and proteins are highly related to the axonal growth network. These data suggest that miRNAs altered by CSPGs functionally target these genes for mediating the inhibitory effect of CSPGs on axonal growth. Conclusions: Our bioinformatic analyses of miRNAs and proteins in the distal axon identifies an interconnected group of miRNAs and their target genes that regulate axonal growth, which provides new insight into the molecular mechanisms underlying axonal growth.

scholarly journals Immunolocalization of a neuronal growth-dependent membrane glycoprotein.

1985 ◽  
Vol 101 (5) ◽  
pp. 1990-1998 ◽  
Author(s):  
I Wallis ◽  
L Ellis ◽  
K Suh ◽  
K H Pfenninger
Keyword(s):  
Spinal Cord ◽  
Nervous System ◽  
Growth Cone ◽  
Cortical Neurons ◽  
Axonal Growth ◽  
Staining Intensity ◽  
Olfactory Nerve ◽  
Membrane Glycoprotein ◽  
Neural Cells ◽  
Developing Spinal Cord

Monoclonal antibody (mAb) 5B4 recognizes in the rat a large, developmentally regulated membrane glycoprotein. The larger form of this antigen (185-255 kD) occurs in the developing nervous system and is present in membranes of nerve growth cones, as determined by analysis of a growth cone particle fraction. An immunochemical characterization of this antigen and of a smaller form (140 kD), sparsely present in the mature nervous system, has been described (Ellis, L., I. Wallis, E. Abreu, and K. H. Pfenninger, 1985, J. Cell. Biol., 101:1977-1989). The present paper reports on the localization by immunofluorescence of 5B4 antigen in cultured cortical neurons, developing spinal cord, and the mature olfactory system. In culture, mAb 5B4 stains only neurons; it is sparsely present in neurons at the onset of sprouting while, during sprouting, it appears to be concentrated at the growth cone and in regions of the perikaryon. In the developing spinal cord, 5B4 labeling is faintly detectable on embryonic day 11 but is intense on fetal day 13. At this stage, the fluorescence is observed in regions of the cord where axonal growth is occurring, while areas composed of dividing or migrating neural cells are nonfluorescent. With maturation of the spinal cord, this basic pattern of fluorescence persists initially, but the staining intensity decreases dramatically. In the adult, faint fluorescence is detectable only in gray matter, presumably indicating the presence of the 140 kD rather than the fetal antigen. The only known structure of the adult mammalian nervous system where axonal growth normally occurs is the olfactory nerve. mAb 5B4 intensely stains a variable proportion of olfactory axons in the mucosa as well as in the olfactory bulb. Based on both immunochemical and immunofluorescence data, the 5B4 antigen of 185-255 kD is associated specifically with growing neurons, i.e., neurons that are generating neurites.

scholarly journals Genetic variants in autism-related CNTNAP2 impair axonal growth of cortical neurons

2018 ◽  
Vol 27 (11) ◽  
pp. 1941-1954 ◽  
Author(s):  
Giorgia Canali ◽  
Marta Garcia ◽  
Bruno Hivert ◽  
Delphine Pinatel ◽  
Aline Goullancourt ◽  
...  
Keyword(s):  
Genetic Variants ◽  
Cortical Neurons ◽  
Axonal Growth

Abstract 68: Exosomes from Rhesus Monkey MSCs Promote Neuronal Growth and Myelination

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Benjamin Buller ◽  
Tara Moore ◽  
Yi Zhang ◽  
Elizabeth Pikula ◽  
Christopher Martin ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Rhesus Monkey ◽  
Cortical Neurons ◽  
Therapeutic Potential ◽  
Brain Slices ◽  
Axonal Growth ◽  
Oligodendrocyte Progenitor Cells ◽  
Rat Pups ◽  
Functional Benefit ◽  
Microfluidic Chamber

Introduction: Treatment of rodents with bone marrow mesenchymal stromal cells (MSCs) enhances functional recovery after stroke. We have shown in a series of studies that much or all of this effect is mediated through release of exosomes--small, membrane bound vesicles that contain many biomolecules--by the MSCs, and that functional benefit is dependent on white matter remodeling. Hypothesis: We hypothesize that exosomes derived from monkey MSCs enhance axonal growth and myelination. Methods: We isolated MSCs from the bone marrow of a young adult rhesus monkey, and harvested their exosomes from MSC culture medium. Results: We first investigated the effect of exosomes on cultured organotypic brain slices from the cerebrum of rat pups. Treatment of brain slices with exosomes markedly increased myelination in cortex and corpus callosum compared to control. Image analysis of 3D reconstructions showed that exosomes increased connections of oligodendrocyte processes with axons by 48%, suggesting enhancement of initiation of myelination. To examine the effect of exosomes directly on neurons and oligodendrocyte progenitor cells (OPCs), exosomes were applied to either cortical neurons cultured in a microfluidic chamber or OPCs. We found that exosomes significantly (p<0.05) increased axonal length (526±22μm vs. 320±15μm for control, n=75/group) and increased the number of NG2+ OPCs by twofold compared to control (P < 0.01). However, exosomes had no significant effect on mature, MBP expressing oligodendrocytes. Conclusion: Our data suggest that exosomes enhance myelination by a two-pronged effect. First, they promote axonal growth, and second, they increase the number of available OPCs. Increased axonal growth may trigger OPCs to myelinate axons. This work is the first to demonstrate the therapeutic potential of monkey exosomes for axonal growth and myelination.

scholarly journals Leptin Increases Axonal Growth Cone Size in Developing Mouse Cortical Neurons by Convergent Signals Inactivating Glycogen Synthase Kinase-3β

2006 ◽  
Vol 281 (18) ◽  
pp. 12950-12958 ◽  
Author(s):  
Alessandra Valerio ◽  
Valentina Ghisi ◽  
Marta Dossena ◽  
Cristina Tonello ◽  
Antonio Giordano ◽  
...  
Keyword(s):  
Growth Cone ◽  
Cortical Neurons ◽  
Glycogen Synthase ◽  
Axonal Growth ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3Β ◽  
Axonal Growth Cone

scholarly journals Exosomes Derived from Mesenchymal Stromal Cells Promote Axonal Growth of Cortical Neurons

2016 ◽  
Vol 54 (4) ◽  
pp. 2659-2673 ◽  
Author(s):  
Yi Zhang ◽  
Michael Chopp ◽  
Xian Shuang Liu ◽  
Mark Katakowski ◽  
Xinli Wang ◽  
...  
Keyword(s):  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Cortical Neurons ◽  
Axonal Growth
Sign in / Sign up

Export Citation Format

Share Document