Neuroprotection and Repair after Spinal Cord Injury
Jacques Corcos, Gilles Karsenty, Thomas Kessler, David Ginsberg in Essentials of the Adult Neurogenic Bladder, 2020
It has long been recognized that CNS myelin is a nonpermissive substrate for neurite extension.47 Attempts to identify the molecular components responsible for that inhibition have identified three proteins of key interest: Nogo,48 MAG, and oligodendrocyte myelin glycoprotein.49,50 These ligands and their shared receptors, therefore, provide targets that may disinhibit neurite extension in a myelin environment. Inhibition of Nogo using a portion of its receptor or neutralizing antiserum has shown evidence of improved axonal extension and improved functional recovery.51,52 Anti-Nogo-A antibody has been shown to promote axonal sprouting and improve functional recovery following injury.53 A non-randomized, open-label phase I clinical trial of humanized anti-Nogo-A antibody was initiated to assess the feasibility, tolerability, and safety of either repeated intrathecal bolus injections or continuous intrathecal delivery in acute SCI (4–14 days after injury); results are pending (ATI-355; Novartis Pharmaceuticals).
Plaques, Tangles and Amyloid:
Robert E. Becker, Ezio Giacobini in Alzheimer Disease, 2020
An initial stage of AD-type cortical SP formation has been suggested to be represented by circular disruption of the neuropil, without evidence of β-amyloid or abnormal neurites (Probst et al, 1987). Stereologic estimates also suggested that each of these “early” SP had a microglia at its core. The distribution and amorphous nature of this type of plaque led those authors to suggest that it might presage the formation of a classic SP containing both neurites and β-amyloid. The predominance of “early” SP, in the absence of the classic SP, in specific cortical areas was explained by proposing that the evolution of the SP was arrested. If this neuropil abnormality does indeed represent a primitive plaque, and that continuation to a classic SP can be arrested, it suggests that SP formation is regulated by local factors, and that the type of SP formed (or whether they are formed at all) is largely determined by the cortical neuropil. This hypothesis is comparable to that suggested for the transmitter- specificity of neurites in plaques, i.e., it is largely related to the local characteristics of the neuropil. Finally, antisera raised against the A4 protein have detected clusters of immuno- staining not visualized with thioflavin, Congo red or routine silver stains. These reports suggest that an early stage of senile plaque formation (Tagliavini et al, 1988; Braak et al, 1989) might be characterized by deposits of β-amyloidogenic peptide not yet in a β-pleated sheet.
Stimulus-Receptive Conductive Polymers for Tissue Engineering
Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon in Tissue Engineering Strategies for Organ Regeneration, 2020
In addition, neurons, which are the basic functional unit of the nervous system, are electrically excitable cells, transmitting neural impulses at a rapid pace (Li et al. 2006, Wang et al. 2008, Hsiao et al. 2013, McKeon et al. 2010, Jun et al. 2009, Feng et al. 2013). Electrical stimulation has been recognized to be an effective element in enhancing nerve regeneration such as neurite growth and nerve regeneration. Thus, an electrically conductive scaffold acts as an effective and excellent scaffold in delivering electrical impulses to cultured neurons. The neural cells stimulated on nanofibrous PANI-PCL/Gelatin scaffold were demonstrated to enhance proliferation and neurite outgrowth (Li et al. 2006). Similarly, the density of viable neurons was reported to experience a greater than ten-fold increase after culturing on the composite of blended PANI and polypropylene (PANI-PP). Nanofibers of PANI/PLLA were proved to enhance the viability and proliferation of the cultured nerve stem cells significantly.
PDGF as an Important Initiator for Neurite Outgrowth Associated with Fibrovascular Membranes in Proliferative Diabetic Retinopathy
Published in Current Eye Research, 2022
Evy Lefevere, Inge Van Hove, Jurgen Sergeys, David H. W. Steel, Reinier Schlingemann, Lieve Moons, Ingeborg Klaassen
The observed effects of PDGF on neurite outgrowth confirm the results from previous studies. Cultured primary rat neuronal cells treated with PDGF-BB for 2 days resulted in extended cell survival and increased outgrowth of neurites.18 In addition, prolonged incubation of more than 10 days with PDGF-BB resulted in an extended survival of cultured GABAergic interneurons.32 PDGF-BB was also found to stimulate proliferation of Müller cells and PDGF receptor phosphorylation, which was blocked by a PDGFR-selective tyrosine kinase inhibitor.19 Müller cells may play a role in the formation of FVMs in PDR. Proliferating Müller cells are considered to be a scaffold for neurites to grow on,7,33 and recently, Müller glial–mesenchymal transition was postulated as an alternative fibrinogenic mechanism associated with membrane formation in PDR.11 Another recent study showed that proliferation and migration of cultured Müller cells were stimulated by vitreous of PDR patients (Rezzola et al. 2021).34 Together, this provides further evidence for a role of Müller cells in the formation of FVMs in PDR.
Acute enhancing effect of a standardized extract of Centella asiatica (ECa 233) on synaptic plasticity: an investigation via hippocampal long-term potentiation
Published in Pharmaceutical Biology, 2021
Yingrak Boondam, Mayuree H. Tantisira, Kanokwan Tilokskulchai, Sompol Tapechum, Narawut Pakaprot
According to our study results, the basal excitatory synaptic transmission was not altered by the direct perfusion of ECa 233 on acute hippocampal slices at any concentrations, and only ECa 233 at 10 µg/mL concentration enhanced the hippocampal LTP magnitude after HFS; even after ECa 233 removal, the LTP magnitude further increased significantly. The pattern of ECa 233-induced LTP is similar to that of BDNF-induced EPSP responses (Kang et al. 1997; Bramham and Messaoudi 2005); it is also similar to the pattern of LTP after the chronic ECa 233 treatment in normal rats in our previous study (Boondam et al. 2019). Upregulation of several NMDAR subunits, PSD-95, p-CaMKII, p-PKACβ, p-CREB, BDNF, and TrkB, after the administration of C. asiatica extract, including its parent compounds, could promote the expression of hippocampal LTP and synaptic formation (Lin et al. 2004; Yin et al. 2015; Boondam et al. 2019). Especially, the upregulation of NMDAR subunits is necessary for LTP formation in the Schaffer collateral pathway of the hippocampus (Tsien et al. 2012). Moreover, low dosages of C. asiatica extract elevated the expression of AMPAR subunit, which is essential for stabilizing the synaptic strength (Binti Mohd Yusuf Yeo et al. 2018). After TrkA or TrkB receptor activation, both asiaticoside and madecassoside had more potency for the sustained activation of MEK/ERK-CREB phosphorylation and PI3K/Akt pathways than asiatic acid and madecassic acid (Nalinratana et al. 2018). Molecular activation promoted the neurite outgrowth, which is a necessary process for memory enhancement.
A perspective on C. elegans neurodevelopment: from early visionaries to a booming neuroscience research
Published in Journal of Neurogenetics, 2020
Concurrently to or after migration, neurons grow neurites to reach their partners. The specification of neurites to become axons or dendrites and dendrite development, in particular, were not subject of early research. However, later work uncovered that axon-dendrite sorting is polarized by ankyrin and kinesin, while guidance cues and neuronal asymmetry define the site of axon formation (Adler, Fetter, & Bargmann, 2006; Maniar et al., 2011). Glial-like mesodermal cells also specify certain axons through calcium signaling (Meng, Zhang, Jin, & Yan, 2016). Recent work reveals that the morphogenesis of dendrites and axons differ. Sensory dendrites form by retrograde extension upon extracellular attachment during neuronal migration (Heiman & Shaham, 2009). Some mechanosensory dendrites grow extensive arborization, driven by hypodermal cues, extracellular matrix, adhesion, and actin effectors (Dong, Liu, Howell, & Shen, 2013; Liu & Shen, 2012; Oren-Suissa, Hall, Treinin, Shemer, & Podbilewicz, 2010; Salzberg et al., 2013; W. Zou et al., 2018). Dendrites are also shaped by self-avoidance and axon-dendrite fasciculation (Chen, Hsu, Chang, & Pan, 2019; Smith, Watson, Vanhoven, Colón-Ramos, & Miller, 2012).
Related Knowledge Centers
- Axon
- Cell Culture
- Dendrite
- Ephrin
- Cellular Differentiation
- Soma
- Neuron
- Netrin
- Semaphorin
- Collapsin Response Mediator Protein Family