Chemical components of Dendrobium crepidatum and their neurite outgrowth enhancing activities
Ontology highlight
ABSTRACT: Electronic Supplementary Material
Supplementary material is available for this article at 10.1007/s13659-012-0103-3 and is accessible for authorized users.
SUBMITTER: Li C
PROVIDER: S-EPMC4131658 | biostudies-literature | 2013 Mar
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Guidance of neuronal extensions is a complex process essential for linking neurons into complex functional networks underlying the workings of the neural system. Decades of research have suggested the ability of neuronal growth cones to integrate multiple types of cues during the extension process, but also have raised numerous still unanswered questions about synergy or antagonism between the superimposed chemical and mechanical signaling inputs. In this study, using a novel microfabricated analysis platform, we investigate the response of primary mouse embryonic hippocampal neurons to superimposed topographic and soluble chemical cues. We find that an optimal spatial frequency of topographic cues exists, maximizing the precision of the neurite extension. This optimal frequency can help the extending neurites navigate a topographically complex environment, providing pronounced directional selectivity. We also demonstrate that this cue can synergistically enhance attractive and suppress repulsive guidance by the bi-functional soluble cue Netrin-1, and eliminate the repulsive guidance by a chemorepellent Semaphorin3A (Sema3A). These results suggest that topographic cues can provide optimal periodic input into the guidance signaling processes involved in growth cone chemoattraction and can synergistically interact with chemical gradients of soluble guidance cues, shedding light on complex events accompanying the development of the functional nervous system.
| S-EPMC3820293 | biostudies-literature
Project description:Due to the increasing number of drugs and untested environmental compounds introduced into commercial use, there is recognition for a need to develop reliable and efficient screening methods to identify compounds that may adversely impact the nervous system. One process that has been implicated in neurodevelopment is neurite outgrowth; the disruption of which can result in adverse outcomes that persist later in life. Here, we developed a green fluorescent protein (GFP) labeled neurite outgrowth assay in a high-content, high-throughput format using induced pluripotent stem cell (iPSC) derived human spinal motor neurons and cortical glutamatergic neurons. The assay was optimized for use in a 1536-well plate format. Then, we used this assay to screen a set of 84 unique compounds that have previously been screened in other neurite outgrowth assays. This library consists of known developmental neurotoxicants, environmental compounds with unknown toxicity, and negative controls. Neurons were cultured for 40 h and then treated with compounds at 11 concentrations ranging from 1.56 nM to 92 μM for 24 and 48 h. Effects of compounds on neurite outgrowth were evaluated by quantifying total neurite length, number of segments, and maximum neurite length per cell. Among the 84 tested compounds, neurite outgrowth in cortical neurons and motor neurons were selectively inhibited by 36 and 31 compounds, respectively. Colchicine, rotenone, and methyl mercuric (II) chloride inhibited neurite outgrowth in both cortical and motor neurons. It is interesting to note that some compounds like parathion and bisphenol AF had inhibitory effects on neurite outgrowth specifically in the cortical neurons, while other compounds, such as 2,2',4,4'-tetrabromodiphenyl ether and caffeine, inhibited neurite outgrowth in motor neurons. The data gathered from these studies show that GFP-labeled iPSC-derived human neurons are a promising tool for identifying and prioritizing compounds with developmental neurotoxicity potential for further hazard characterization.
| S-EPMC9444042 | biostudies-literature
Project description:Understanding the cues that guide axons and how we can optimize these cues to achieve directed neuronal growth is imperative for neural tissue engineering. Cells in the local environment influence neurons with a rich combination of cues. This study deconstructs the complex mixture of guidance cues by working at the biomimetic interface--isolating the topographical information presented by cells and determining its capacity to guide neurons. We generated replica materials presenting topographies of oriented astrocytes (ACs), endothelial cells (ECs), and Schwann cells (SCs) as well as computer-aided design materials inspired by the contours of these cells (bioinspired-CAD). These materials presented distinct topographies and anisotropies and in all cases were sufficient to guide neurons. Dorsal root ganglia (DRG) cells and neurites demonstrated the most directed response on bioinspired-CAD materials which presented anisotropic features with 90 degrees edges. DRG alignment was strongest on SC bioinspired-CAD materials followed by AC bioinspired-CAD materials, with more uniform orientation to EC bioinspired-CAD materials. Alignment on replicas was strongest on SC replica materials followed by AC and EC replicas. These results suggest that the topographies of anisotropic tissue structures are sufficient for neuronal guidance. This work is discussed in the context of feature dimensions, morphology, and guidepost hypotheses.
| S-EPMC3016852 | biostudies-literature
Project description:Regulation of the actin cytoskeleton is critical for neurite formation. Tropomodulins (Tmods) regulate polymerization at actin filament pointed ends. Previous experiments using a mouse model deficient for the neuron specific isoform Tmod2 suggested a role for Tmods in neuronal function by impacting processes underlying learning and memory. However, the role of Tmods in neuronal function on the cellular level remains unknown. Immunofluorescence localization of the neuronal isoforms Tmod1 and Tmod2 in cultured rat primary hippocampal neurons revealed that Tmod1 is enriched along the proximal part of F-actin bundles in lamellipodia of spreading cells and in growth cones of extending neurites, while Tmod2 appears largely cytoplasmic. Functional analysis of these Tmod isoforms in a mouse neuroblastoma N2a cell line showed that knockdown of Tmod2 resulted in a significant increase in the number of neurite-forming cells and in neurite length. While N2a cells compensated for Tmod2 knockdown by increasing Tmod1 levels, over-expression of exogenous Tmod1 had no effect on neurite outgrowth. Moreover, knockdown of Tmod1 increased the number of neurites formed per cell, without effect on the number of neurite-forming cells or neurite length. Taken together, these results indicate that Tmod1 and Tmod2 have mechanistically distinct inhibitory roles in neurite formation, likely mediated via different effects on F-actin dynamics and via differential localizations during early neuritogenesis.
| S-EPMC3042488 | biostudies-literature
Project description:Neuritic outgrowth is a striking example of directed motility, powered through the actions of molecular motors. Members of the myosin superfamily of actin-associated motors have been implicated in this complex process. Although conventional myosin II is known to be present in neurons, where it is localized at the leading edge of growth cones and in the cell cortex close to the plasma membrane, its functional involvement in growth cone motility has remained unproven. Here, we show that antisense oligodeoxyribonucleotides, complementary to a specific isoform of conventional myosin (myosin IIB), attenuate filopodial extension whereas sense and scrambled control oligodeoxyribonucleotides have no effect. Attenuation is shown to be reversible, neurite outgrowth being restored after cessation of the antisense regimen. Myosin IIB mRNA was present during active neurite extension, but levels were minimal in phenotypically rounded cells before neurite outgrowth and message levels decreased during antisense treatment. By contrast, the myosin IIA isoform is shown to be expressed constitutively both before and during neurite outgrowth and throughout exposure to myosin IIB antisense oligodeoxyribonucleotides. These results provide direct evidence that a conventional two-headed myosin is required for growth cone motility and is responsible, at least in part, for driving neuritic process outgrowth.
| S-EPMC23673 | biostudies-literature
Project description:Hericium erinaceus is a culinary-medicinal mushroom used traditionally in Eastern Asia to improve memory. In this work, we investigated the neuroprotective and neuritogenic effects of the secondary metabolites isolated from the MeOH extract of cultured mycelium of H. erinaceus and the primary mechanisms involved. One new dihydropyridine compound (6) and one new natural product (2) together with five known compounds (1,3-5,7) were obtained and their structures were elucidated by spectroscopic analysis, including 2D NMR and HRMS. The cell-based screening for bioactivity showed that 4-chloro-3,5-dimethoxybenzoic methyl ester (1) and a cyathane diterpenoid, erincine A (3), not only potentiated NGF-induced neurite outgrowth but also protected neuronally-differentiated cells against deprivation of NGF in PC12 pheochromocytoma cells. Additionally, compound 3 induced neuritogenesis in primary rat cortex neurons. Furthermore, our results revealed that TrkA-mediated and Erk1/2-dependant pathways could be involved in 1 and 3-promoted NGF-induced neurite outgrowth in PC12 cells.
| S-EPMC5578049 | biostudies-literature
Project description:GIT1, a G-protein-coupled receptor kinase interacting protein, has been reported to be involved in neurite outgrowth. However, the neurobiological functions of the protein remain unclear. In this study, we found that GIT1 was highly expressed in the nervous system, and its expression was maintained throughout all stages of neuritogenesis in the brain. In primary cultured mouse hippocampal neurons from GIT1 knockout mice, there was a significant reduction in total neurite length per neuron, as well as in the average length of axon-like structures, which could not be prevented by nerve growth factor treatment. Overexpression of GIT1 significantly promoted axon growth and fully rescued the axon outgrowth defect in the primary hippocampal neuron cultures from GIT1 knockout mice. The GIT1 N terminal region, including the ADP ribosylation factor-GTPase activating protein domain, the ankyrin domains and the Spa2 homology domain, were sufficient to enhance axonal extension. Importantly, GIT1 bound to many tubulin proteins and microtubule-associated proteins, and it accelerated microtubule assembly in vitro. Collectively, our findings suggest that GIT1 promotes neurite outgrowth, at least partially by stimulating microtubule assembly. This study provides new insight into the cellular and molecular pathogenesis of GIT1-associated neurological diseases.
| S-EPMC4829007 | biostudies-literature
Project description:Neurons, with their long axons and elaborate dendritic arbour, establish the complex circuitry that is essential for the proper functioning of the nervous system. Whereas a catalogue of structural, molecular, and functional differences between axons and dendrites is accumulating, the mechanisms involved in early events of neuronal differentiation, such as neurite initiation and elongation, are less well understood, mainly because the key molecules involved remain elusive. Here we describe the establishment and application of a microscopy-based approach designed to identify novel proteins involved in neurite initiation and/or elongation. We identified 21 proteins that affected neurite outgrowth when ectopically expressed in cells. Complementary time-lapse microscopy allowed us to discriminate between early and late effector proteins. Localization experiments with GFP-tagged proteins in fixed and living cells revealed a further 14 proteins that associated with neurite tips either early or late during neurite outgrowth. Coexpression experiments of the new effector proteins provide a first glimpse on a possible functional relationship of these proteins during neurite outgrowth. Altogether, we demonstrate the potential of the systematic microscope-based screening approaches described here to tackle the complex biological process of neurite outgrowth regulation.
| S-EPMC1751310 | biostudies-literature
Project description:SALMs are a family of five adhesion molecules whose expression is largely restricted to the CNS. Initial reports showed that SALM1 functions in neurite outgrowth while SALM2 is involved in synapse formation. To investigate the function of SALMs in detail, we asked if all five are involved in neurite outgrowth. Expression of epitope-tagged proteins in cultured hippocampal neurons showed that SALMs are distributed throughout neurons, including axons, dendrites, and growth cones. Over-expression of each SALM resulted in enhanced neurite outgrowth, but with different phenotypes. Neurite outgrowth could be reduced by applying antibodies targeting the extracellular leucine rich regions of SALMs and with RNAi. Through over-expression of deletion constructs, we found that the C-terminal PDZ binding domains of SALMs 1-3 are required for most aspects of neurite outgrowth. In addition, by using a chimera of SALMs 2 and 4, we found that the N-terminus is also involved in neurite outgrowth.
| S-EPMC2602877 | biostudies-literature
Project description:We have undertaken a genome-wide study of transcriptional activity in embryonic superior cervical ganglia (SCG) and dorsal root ganglia (DRG) during a time course of neurite outgrowth in vitro. Gene expression observed in these models likely includes both developmental gene expression patterns and regenerative responses to axotomy, which occurs as the result of tissue dissection. Comparison across both models revealed many genes with similar gene expression patterns during neurite outgrowth. These patterns were minimally affected by exposure to the potent inhibitory cue Semaphorin3A, indicating that this extrinsic cue does not exert major effects at the level of nuclear transcription. We also compared our data to several published studies of DRG and SCG gene expression in animal models of regeneration, and found the expression of a large number of genes in common between neurite outgrowth in vitro and regeneration in vivo. Experiment Overall Design: We wished to determine the transcriptional profiles of neurons undergoing neurite outgrowth in vitro. We were particularly interested in finding genes whose expression is generally associated with the process of neurite outgrowth, rather than with cell type-specific effects. Thus, in order to avoid focusing on transcripts unique to one tissue type versus another, we used a comparative strategy to look for effects that were common to two tissue types and therefore more likely to be involved in the general process of neurite outgrowth. While these explants contain multiple cell types, we felt this was preferable to the more disruptive conditions required to dissociate neurons or obtain a pure neuron population. To this end, we monitored gene expression in cultured explants from SCG and DRG using DNA microarrays. We initiated our studies by culturing embryonic day 13 (E13) mouse SCG in vitro and harvesting tissue for RNA isolation at time points from 2 to 65 hours. Time points were selected to detect both fast, short-term responses (2, 5 and 12 hours), as well as sustained, long-term changes (24, 40, and 65 hours). Samples were hybridized to Affymetrix MG-U74v2 A and B microarrays, with RNA from acutely dissected explants serving as a baseline reference. We followed these experiments with a parallel analysis of a more heterogeneous tissue type, the DRG, which is more frequently used than SCG for in vivo studies of neurite regeneration. Cervical and upper thoracic DRG from E12 embryos were cultured with NGF (the same trophic support as in SCG cultures), harvested at time points from 2 to 40 hours, and hybridized to Affymetrix MOE 430A microarrays.
2008-06-16 | E-GEOD-9738 | biostudies-arrayexpress