scholarly journals Ultrasonic control of neurite outgrowth direction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haruki Maruyama ◽  
Koji Fujiwara ◽  
Masahiro Kumeta ◽  
Daisuke Koyama
Keyword(s):  
Neurite Outgrowth ◽  
Flexural Vibration ◽  
Time Lapse ◽  
Vibrational Amplitude ◽  
Spatial Gradient ◽  
Dependent Manner ◽  
Culture Dish ◽  
Bottom Culture ◽  
Adherent Culture ◽  
Time Lapse Imaging

AbstractThis study investigated a method to control neurite outgrowth direction using ultrasound vibration. An ultrasound cell culture dish comprising a glass-bottom culture surface and a glass disc with an ultrasound transducer was fabricated, and undifferentiated neuron-like PC12 cells were grown on the dish as an adherent culture. The 78 kHz resonant concentric flexural vibration mode of the dish was used to quantitatively evaluate the neurite outgrowth direction and length. Time-lapse imaging of cells was performed for 72 h under ultrasound excitation. Unsonicated neurites grew in random directions, whereas neurite outgrowth was circumferentially oriented during ultrasonication in a power-dependent manner. The neurite orientation correlated with the spatial gradient of the ultrasound vibration, implying that neurites tend to grow in directions along which the vibrational amplitude does not change. Ultrasonication with 30 Vpp for 72 h increased the neurite length by 99.7% compared with that observed in unsonicated cells.

scholarly journals Actin Filament Assembly by Myristoylated, Alanine-rich C Kinase Substrate–Phosphatidylinositol-4,5-diphosphate Signaling Is Critical for Dendrite Branching

2008 ◽  
Vol 19 (11) ◽  
pp. 4804-4813 ◽  
Author(s):  
Haimin Li ◽  
Gang Chen ◽  
Bing Zhou ◽  
Shumin Duan
Keyword(s):  
Molecular Mechanisms ◽  
Critical Role ◽  
Time Lapse ◽  
Dependent Manner ◽  
Filamentous Actin ◽  
Kinase Substrate ◽  
Extensive Growth ◽  
Time Lapse Imaging

Dendrites undergo extensive growth and branching at early stages, but relatively little is known about the molecular mechanisms underlying these processes. Here, we show that increasing the level of myristoylated, alanine-rich C kinase substrate (MARCKS), a prominent substrate of protein kinase C and a phosphatidylinositol-4,5-diphosphate [PI(4,5)P2] sequestration protein highly expressed in the brain, enhanced branching and growth of dendrites both in vitro and in vivo. Conversely, knockdown of endogenous MARCKS by RNA interference reduced dendritic arborization. Results from expression of different mutants indicated that membrane binding is essential for MARCKS-induced dendritic morphogenesis. Furthermore, MARCKS increased the number and length of filamentous actin-based filopodia along neurites, as well as the motility of filopodia, in a PI(4,5)P2-dependent manner. Time-lapse imaging showed that MARCKS increased frequency of filopodia initiation but did not affect filopodia longevity, suggesting that MARCKS may increase dendritic branching through its action on filopodia initiation. These findings demonstrate a critical role for MARCKS–PI(4,5)P2 signaling in regulating dendrite development.

scholarly journals Myelin biogenesis is associated with pathological ultrastructure that is resolved by microglia during development

2021 ◽  
Author(s):  
Minou Djannatian ◽  
Ulrich Weikert ◽  
Shima Safaiyan ◽  
Christoph Wrede ◽  
Cassandra Deichsel ◽  
...  
Keyword(s):  
Action Potentials ◽  
Time Lapse ◽  
Ultrastructural Changes ◽  
Dependent Manner ◽  
Membrane Structures ◽  
Dynamic Changes ◽  
Early Postnatal Development ◽  
Myelin Sheaths ◽  
Block Face ◽  
Time Lapse Imaging

ABSTRACTTo enable rapid propagation of action potentials, axons are ensheathed by myelin, a multilayered insulating membrane formed by oligodendrocytes. Most of the myelin is generated early in development, in a process thought to be error-free, resulting in the generation of long-lasting stable membrane structures. Here, we explored structural and dynamic changes in CNS myelin during development by combining ultrastructural analysis of mouse optic nerves by serial block face scanning electron microscopy and confocal time-lapse imaging in the zebrafish spinal cord. We found that myelin undergoes extensive ultrastructural changes during early postnatal development. Myelin degeneration profiles were engulfed and phagocytosed by microglia in a phosphatidylserine-dependent manner. In contrast, retractions of entire myelin sheaths occurred independently of microglia and involved uptake of myelin by the oligodendrocyte itself. Our findings show that the generation of myelin early in development is an inaccurate process associated with aberrant ultrastructural features that requires substantial refinement.

Cleavage of Human Embryos: Options and Diversity

Acta Naturae ◽  
2016 ◽  
Vol 8 (3) ◽  
pp. 88-96
Author(s):  
Yu. K. Doronin ◽  
I. V. Senechkin ◽  
L. V. Hilkevich ◽  
M. A. Kurcer
Keyword(s):  
Time Lapse ◽  
Reproductive Technologies ◽  
Human Embryos ◽  
Imaging Data ◽  
Noninvasive Methods ◽  
Topographic Features ◽  
Time Parameters ◽  
Embryo Cleavage ◽  
Time Lapse Imaging ◽  
Developmental Dynamics

In order to estimate the diversity of embryo cleavage relatives to embryo progress (blastocyst formation), time-lapse imaging data of preimplantation human embryo development were used. This retrospective study is focused on the topographic features and time parameters of the cleavages, with particular emphasis on the lengths of cleavage cycles and the genealogy of blastomeres in 2- to 8-cell human embryos. We have found that all 4-cell human embryos have four developmental variants that are based on the sequence of appearance and orientation of cleavage planes during embryo cleavage from 2 to 4 blastomeres. Each variant of cleavage shows a strong correlation with further developmental dynamics of the embryos (different cleavage cycle characteristics as well as lengths of blastomere cycles). An analysis of the sequence of human blastomere divisions allowed us to postulate that the effects of zygotic determinants are eliminated as a result of cleavage, and that, thereafter, blastomeres acquire the ability of own syntheses, regulation, polarization, formation of functional contacts, and, finally, of specific differentiation. This data on the early development of human embryos obtained using noninvasive methods complements and extend our understanding of the embryogenesis of eutherian mammals and may be applied in the practice of reproductive technologies.

scholarly journals Evaluating the utility of time-lapse imaging in the estimation of post-mortem interval: An Australian case study

2019 ◽  
Vol 1 ◽  
pp. 204-210 ◽  
Author(s):  
Alyson Wilson ◽  
Stanley Serafin ◽  
Dilan Seckiner ◽  
Rachel Berry ◽  
Xanthé Mallett
Keyword(s):  
Time Lapse ◽  
Post Mortem ◽  
Post Mortem Interval ◽  
Australian Case ◽  
Time Lapse Imaging

scholarly journals Myelin basic protein enhances axonal regeneration from neural progenitor cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhengjian Yan ◽  
Lei Chu ◽  
Xiaojiong Jia ◽  
Lu Lin ◽  
Si Cheng
Keyword(s):  
Myelin Basic Protein ◽  
Neurite Outgrowth ◽  
Progenitor Cells ◽  
Axonal Regeneration ◽  
Neural Progenitor Cells ◽  
Basic Protein ◽  
Neural Progenitor ◽  
Dependent Manner ◽  
Cord Injury

Abstract Introduction Stem cell therapy using neural progenitor cells (NPCs) shows promise in mitigating the debilitating effects of spinal cord injury (SCI). Notably, myelin stimulates axonal regeneration from mammalian NPCs. This led us to hypothesize that myelin-associated proteins may contribute to axonal regeneration from NPCs. Methods We conducted an R-based bioinformatics analysis to identify key gene(s) that may participate in myelin-associated axonal regeneration from murine NPCs, which identified the serine protease myelin basic protein (Mbp). We employed E12 murine NPCs, E14 rat NPCs, and human iPSC-derived Day 1 NPCs (D1 hNPCs) with or without CRISPR/Cas9-mediated Mbp knockout in combination with rescue L1-70 overexpression, constitutively-active VP16-PPARγ2, or the PPARγ agonist ciglitazone. A murine dorsal column crush model of SCI utilizing porous collagen-based scaffolding (PCS)-seeded murine NPCs with or without stable Mbp overexpression was used to assess locomotive recovery and axonal regeneration in vivo. Results Myelin promotes axonal outgrowth from NPCs in an Mbp-dependent manner and that Mbp’s stimulatory effects on NPC neurite outgrowth are mediated by Mbp’s production of L1-70. Furthermore, we determined that Mbp/L1-70’s stimulatory effects on NPC neurite outgrowth are mediated by PPARγ-based repression of neuron differentiation-associated gene expression and PPARγ-based Erk1/2 activation. In vivo, PCS-seeded murine NPCs stably overexpressing Mbp significantly enhanced locomotive recovery and axonal regeneration in post-SCI mice. Conclusions We discovered that Mbp supports axonal regeneration from mammalian NPCs through the novel Mbp/L1cam/Pparγ signaling pathway. This study suggests that bioengineered, NPC-based interventions can promote axonal regeneration and functional recovery post-SCI.

scholarly journals Time-lapse imaging of CO2 migration within near-surface sediments during a controlled sub-seabed release experiment

2021 ◽  
Vol 109 ◽  
pp. 103363
Author(s):  
Ben Roche ◽  
Jonathan M. Bull ◽  
Hector Marin-Moreno ◽  
Timothy G. Leighton ◽  
Ismael H. Falcon-Suarez ◽  
...  
Keyword(s):  
Surface Sediments ◽  
Time Lapse ◽  
Near Surface ◽  
Release Experiment ◽  
Time Lapse Imaging

scholarly journals Developmental Neurotoxicity of Fipronil and Rotenone on a Human Neuronal In Vitro Test System

2021 ◽  
Author(s):  
Anne Schmitz ◽  
Silke Dempewolf ◽  
Saime Tan ◽  
Gerd Bicker ◽  
Michael Stern
Keyword(s):  
Cell Migration ◽  
Neurite Outgrowth ◽  
Neuronal Differentiation ◽  
Precursor Cell ◽  
Developmental Neurotoxicity ◽  
In Vitro Studies ◽  
Human Model ◽  
In Vitro Test ◽  
Dependent Manner

AbstractPesticide exposure during in utero and early postnatal development can cause a wide range of neurological defects. However, relatively few insecticides have been recognized as developmental neurotoxicants, so far. Recently, discovery of the insecticide, fipronil, in chicken eggs has raised public concern. The status of fipronil as a potential developmental neurotoxicant is still under debate. Whereas several in vivo and in vitro studies suggest specific toxicity, other in vitro studies could not confirm this concern. Here, we tested fipronil and its main metabolic product, fipronil sulfone both at concentrations between 1.98 and 62.5 µM, alongside with the established developmental neurotoxicant, rotenone (0.004–10 µM) in vitro on the human neuronal precursor cell line NT2. We found that rotenone impaired all three tested DNT endpoints, neurite outgrowth, neuronal differentiation, and precursor cell migration in a dose-dependent manner and clearly separable from general cytotoxicity in the nanomolar range. Fipronil and fipronil sulfone specifically inhibited cell migration and neuronal differentiation, but not neurite outgrowth in the micromolar range. The rho-kinase inhibitor Y-27632 counteracted inhibition of migration for all three compounds (EC50 between 12 and 50 µM). The antioxidant, n-acetyl cysteine, could ameliorate the inhibitory effects of fipronil on all three tested endpoints (EC 50 between 84 and 164 µM), indicating the involvement of oxidative stress. Fipronil sulfone had a stronger effect than fipronil, confirming the importance to test metabolic products alongside original pesticides. We conclude that in vitro fipronil and fipronil sulfone display specific developmental neurotoxicity on developing human model neurons.

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