Strength-frequency curve for micromagnetic neurostimulation through excitatory postsynaptic potentials (EPSPs) on rat hippocampal neurons and numerical modeling of magnetic microcoil (μcoil)

Abstract Objective: The objective of this study was to measure the effect of micromagnetic stimulation (μMS) on hippocampal neurons, by using single microcoil (μcoil) prototype, Magnetic Pen (MagPen). MagPen will be used to stimulate the CA3 magnetically and excitatory post synaptic potential (EPSP) measurements will be made from the CA1. The threshold for μMS as a function of stimulation frequency of the current driving the µcoil will be demonstrated. Finally, the optimal stimulation frequency of the current driving the μcoil to minimize power will be estimated. Approach: A biocompatible prototype, MagPen was built, and customized such that it is easy to adjust the orientation of the μcoil over the hippocampal tissue in an in vitro setting. Finite element modeling (FEM) of the μcoil was performed to estimate the spatial profiles of the magnetic flux density (in T) and the induced electric fields (in V/m). The induced electric field profiles generated at different values of current applied to the µcoil whether can elicit a neuron response was validated by numerical modeling. The modeling settings were replicated in experiments on rat hippocampal neurons. Main results: The preferred orientation of MagPen over the Schaffer Collateral fibers was demonstrated such that they elicit a neuron response. The recorded EPSPs from CA1 due to μMS at CA3 were validated by applying tetrodotoxin (TTX). Finally, it was interpreted through numerical analysis that increasing frequency of the current driving the μcoil, led to a decrease in the current amplitude threshold for μMS. Significance: This work reports that μMS can be used to evoke population EPSPs in the CA1 of hippocampus. It demonstrates the strength-frequency curve for µMS and its unique features related to orientation dependence of the µcoils, spatial selectivity and distance dependence. Finally, the challenges related to µMS experiments were studied including ways to overcome them.

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Strength-frequency curve for micromagnetic neurostimulation through EPSPs on rat hippocampal neurons and numerical modeling of magnetic microcoil (μcoil)

10.1101/2021.11.30.470598 ◽

2021 ◽

Author(s):

Renata Saha ◽

Sadegh Faramarzi ◽

Robert P. Bloom ◽

Onri J. Benally ◽

Kai Wu ◽

...

Keyword(s):

Numerical Modeling ◽

Electric Fields ◽

Hippocampal Neurons ◽

Stimulation Frequency ◽

Magnetic Flux Density ◽

Partial Recovery ◽

Ca1 Region ◽

Neuron Response ◽

Ca3 Region

AbstractObjectiveThe objective of this study was to measure the effect of micromagnetic stimulation (μMS) on hippocampal neurons, by using single microcoil (μcoil) prototype, Magnetic Pen (MagPen). MagPen will be used to stimulate the CA3 region magnetically and excitatory post synaptic potential (EPSP) response measurements will be made from the CA1 region. The threshold for micromagnetic neurostimulation as a function of stimulation frequency of the current driving the μcoil will be demonstrated. Finally, the optimal stimulation frequency of the current driving the μcoil to minimize power will be estimated.ApproachA biocompatible, watertight, non-corrosive prototype, MagPen was built, and customized such that it is easy to adjust the orientation of the μcoil and its distance over the hippocampal tissue in an in vitro recording setting. Finite element modeling (FEM) of the μcoil design was performed to estimate the spatial profiles of the magnetic flux density (in T) and the induced electric fields (in V/m). The induced electric field profiles generated at different values of current applied to the μcoil can elicit a neuron response, which was validated by numerical modeling. The modeling settings for the μcoil were replicated in experiments on rat hippocampal neurons.Main resultsThe preferred orientation of MagPen over the Schaffer Collateral fibers was demonstrated such that they elicit a neuron response. The recorded EPSPs from CA1 region due to μMS at CA3 region were validated by applying tetrodotoxin (TTX). Application of TTX to the hippocampal slice blocked the EPSPs from μMS while after prolonged TTX washout, a partial recovery of the EPSP from μMS was observed. Finally, it was interpreted through numerical analysis that increasing frequency of the current driving the μcoil, led to a decrease in the current amplitude threshold for micromagnetic neurostimulation.SignificanceThis work reports that micromagnetic neurostimulation can be used to evoke population EPSP responses in the CA1 region of the hippocampus. It demonstrates the strengthfrequency curve for μMS and its unique features related to orientation dependence of the μcoils, spatial selectivity and stimulation threshold related to distance dependence. Finally, the challenges related to μMS experiments were studied including ways to overcome them.

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Astrocytic Expression of the Immunoreceptor CD300f Protects Hippocampal Neurons from Amyloid-β Oligomer Toxicity In Vitro

Current Alzheimer Research ◽

10.2174/1567205014666170202121709 ◽

2017 ◽

Vol 14 (7) ◽

Cited By ~ 1

Author(s):

Thiago Zaqueu Lima ◽

Luis Roberto Sardinha ◽

Joan Sayos ◽

Luiz Eugenio Mello ◽

Hugo Peluffo

Keyword(s):

Hippocampal Neurons ◽

Amyloid Β ◽

Toxicity In Vitro

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Computational and In-Vitro Validation of Natural Molecules as Potential Acetylcholinesterase Inhibitors and Neuroprotective Agents

Current Alzheimer Research ◽

10.2174/1567205016666181212155147 ◽

2019 ◽

Vol 16 (2) ◽

pp. 116-127 ◽

Cited By ~ 2

Author(s):

Ashwani Kumar ◽

Vineet Mehta ◽

Utkarsh Raj ◽

Pritish Kumar Varadwaj ◽

Malairaman Udayabanu ◽

...

Keyword(s):

In Silico ◽

Hippocampal Neurons ◽

Symptomatic Relief ◽

In Vitro Assays ◽

Disease Modifying Drugs ◽

In Silico Docking ◽

Ache Inhibitors ◽

Significant Difference ◽

Disease Modifying

Background: Cholinesterase inhibitors are the first line of therapy for the management of Alzheimer’s disease (AD), however, it is now established that they provide only temporary and symptomatic relief, besides, having several inherited side-effects. Therefore, an alternative drug discovery method is used to identify new and safer ‘disease-modifying drugs’. Methods: Herein, we screened 646 small molecules of natural origin having reported pharmacological and functional values through in-silico docking studies to predict safer neuromodulatory molecules with potential to modulate acetylcholine metabolism. Further, the potential of the predicted molecules to inhibit acetylcholinesterase (AChE) activity and their ability to protect neurons from degeneration was determined through in-vitro assays. Results: Based on in-silico AChE interaction studies, we predicted quercetin, caffeine, ascorbic acid and gallic acid to be potential AChE inhibitors. We confirmed the AChE inhibitory potential of these molecules through in-vitro AChE inhibition assay and compared results with donepezil and begacestat. Herbal molecules significantly inhibited enzyme activity and inhibition for quercetin and caffeine did not show any significant difference from donepezil. Further, the tested molecules did not show any neurotoxicity against primary (E18) hippocampal neurons. We observed that quercetin and caffeine significantly improved neuronal survival and efficiently protected hippocampal neurons from HgCl2 induced neurodegeneration, which other molecules, including donepezil and begacestat, failed to do. Conclusion: Quercetin and caffeine have the potential as “disease-modifying drugs” and may find application in the management of neurological disorders such as AD.

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Spastin Interacts with CRMP2 to Regulate Neurite Outgrowth by Controlling Microtubule Dynamics through Phosphorylation Modifications

CNS & Neurological Disorders - Drug Targets ◽

10.2174/1871527319666201026165855 ◽

2020 ◽

Vol 19 ◽

Author(s):

Sumei Li ◽

Jifeng Zhang ◽

Jiaqi Zhang ◽

Jiong Li ◽

Longfei Cheng ◽

...

Keyword(s):

Neurite Outgrowth ◽

Hippocampal Neurons ◽

Neuronal Development ◽

Phosphorylation Site ◽

Microtubule Dynamics ◽

Microtubule Assembly ◽

C Terminus ◽

Mediator Protein ◽

Branch Formation

Aims: Our work aims to revealing the underlying microtubule mechanism of neurites outgrowth during neuronal development, and also proposes a feasible intervention pathway for reconstructing neural network connections after nerve injury. Background: Microtubule polymerization and severing are the basis for the neurite outgrowth and branch formation. Collapsin response mediator protein 2 (CRMP2) regulates axonal growth and branching as a binding partner of the tubulin heterodimer to promote microtubule assembly. And spastin participates in the growth and regeneration of neurites by severing microtubules into small segments. However, how CRMP2 and spastin cooperate to regulate neurite outgrowth by controlling the microtubule dynamics needs to be elucidated. Objective: To explore whether neurite outgrowth was mediated by coordination of CRMP2 and spastin. Method: Hippocampal neurons were cultured in vitro in 24-well culture plates for 4 days before being used to perform the transfection. Calcium phosphate was used to transfect the CRMP2 and spastin constructs and their control into the neurons. An interaction between CRMP2 and spastin was examined by using pull down, CoIP and immunofluorescence colocalization assays. And immunostaining was also performed to determine the morphology of neurites. Result: We first demonstrated that CRMP2 interacted with spastin to promote the neurite outgrowth and branch formation. Furthermore, our results identified that phosphorylation modification failed to alter the binding affinities of CRMP2 for spastin, but inhibited their binding to microtubules. CRMP2 interacted with the MTBD domain of spastin via its C-terminus, and blocking the binding sites of them inhibited the outgrowth and branch formation of neurites. In addition, we confirmed one phosphorylation site S210 at spastin in hippocampal neurons and phosphorylation spastin at site S210 promoted the neurite outgrowth but not branch formation by remodeling microtubules. Conclusion: Taken together, our data demonstrated that the interaction of CRMP2 and spastin is required for neurite outgrowth and branch formation and their interaction is not regulated by their phosphorylation.

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H2S protects hippocampal neurons against hypoxia-reoxygenation injury by promoting RhoA phosphorylation at Ser188

Cell Death Discovery ◽

10.1038/s41420-021-00514-z ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Ye Chen ◽

Jiyue Wen ◽

Zhiwu Chen

Keyword(s):

Endothelial Cells ◽

Hippocampal Neurons ◽

Glucose Deprivation ◽

Rhoa Activity ◽

Mercaptopyruvate Sulfurtransferase ◽

Dependent Protein ◽

Cerebral Vasodilatation ◽

Reoxygenation Injury ◽

Hypoxia Reoxygenation

AbstractInhibition of RhoA-ROCK pathway is involved in the H2S-induced cerebral vasodilatation and H2S-mediated protection on endothelial cells against oxygen-glucose deprivation/reoxygenation injury. However, the inhibitory mechanism of H2S on RhoA-ROCK pathway is still unclear. The aim of this study was to investigate the target and mechanism of H2S in inhibition of RhoA/ROCK. GST-RhoAwild and GST-RhoAS188A proteins were constructed and expressed, and were used for phosphorylation assay in vitro. Recombinant RhoAwild-pEGFP-N1 and RhoAS188A-pEGFP-N1 plasmids were constructed and transfected into primary hippocampal nerve cells (HNCs) to evaluate the neuroprotective mechanism of endothelial H2S by using transwell co-culture system with endothelial cells from cystathionine-γ-lyase knockout (CSE−/−) mice and 3-mercaptopyruvate sulfurtransferase knockout (3-MST−/−) rats, respectively. We found that NaHS, exogenous H2S donor, promoted RhoA phosphorylation at Ser188 in the presence of cGMP-dependent protein kinase 1 (PKG1) in vitro. Besides, both exogenous and endothelial H2S facilitated the RhoA phosphorylation at Ser188 in HNCs, which induced the reduction of RhoA activity and membrane transposition, as well as ROCK2 activity and expression. To further investigate the role of endothelial H2S on RhoA phosphorylation, we detected H2S release from ECs of CSE+/+ and CSE−/− mice, and 3-MST+/+ and 3-MST−/− rats, respectively, and found that H2S produced by ECs in the culture medium is mainly catalyzed by CSE synthase. Moreover, we revealed that both endothelial H2S, mainly catalyzed by CSE, and exogenous H2S protected the HNCs against hypoxia-reoxygenation injury via phosphorylating RhoA at Ser188.

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Neurotrophic Properties of Silexan, an Essential Oil from the Flowers of Lavender-Preclinical Evidence for Antidepressant-Like Properties

Pharmacopsychiatry ◽

10.1055/a-1293-8585 ◽

2020 ◽

Vol 54 (01) ◽

pp. 37-46

Author(s):

Kristina Friedland ◽

Giacomo Silani ◽

Anita Schuwald ◽

Carola Stockburger ◽

Egon Koch ◽

...

Keyword(s):

Essential Oil ◽

Hippocampal Neurons ◽

Day Treatment ◽

Neuronal Cell ◽

Antidepressant Activity ◽

In Vivo Models ◽

Antidepressant Effects ◽

Primary Hippocampal Neurons

Abstract Background Silexan, a special essential oil from flowering tops of lavandula angustifolia, is used to treat subsyndromal anxiety disorders. In a recent clinical trial, Silexan also showed antidepressant effects in patients suffering from mixed anxiety-depression (ICD-10 F41.2). Since preclinical data explaining antidepressant properties of Silexan are missing, we decided to investigate if Silexan also shows antidepressant-like effects in vitro as well as in vivo models. Methods We used the forced swimming test (FST) in rats as a simple behavioral test indicative of antidepressant activity in vivo. As environmental events and other risk factors contribute to depression through converging molecular and cellular mechanisms that disrupt neuronal function and morphology—resulting in dysfunction of the circuitry that is essential for mood regulation and cognitive function—we investigated the neurotrophic properties of Silexan in neuronal cell lines and primary hippocampal neurons. Results The antidepressant activity of Silexan (30 mg/kg BW) in the FST was comparable to the tricyclic antidepressant imipramine (20 mg/kg BW) after 9-day treatment. Silexan triggered neurite outgrowth and synaptogenesis in 2 different neuronal cell models and led to a significant increase in synaptogenesis in primary hippocampal neurons. Silexan led to a significant phosphorylation of protein kinase A and subsequent CREB phosphorylation. Conclusion Taken together, Silexan demonstrates antidepressant-like effects in cellular as well as animal models for antidepressant activity. Therefore, our data provides preclinical evidence for the clinical antidepressant effects of Silexan in patients with mixed depression and anxiety.

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Establishment of a New Device for Electrical Stimulation of Non-Degenerative Cartilage Cells In Vitro

International Journal of Molecular Sciences ◽

10.3390/ijms22010394 ◽

2021 ◽

Vol 22 (1) ◽

pp. 394

Author(s):

Simone Krueger ◽

Alexander Riess ◽

Anika Jonitz-Heincke ◽

Alina Weizel ◽

Anika Seyfarth ◽

...

Keyword(s):

Electrical Stimulation ◽

Electric Fields ◽

Cartilage Tissue ◽

Type I ◽

Dependent Manner ◽

New Device ◽

Alternating Electric Fields ◽

Cartilage Cells ◽

Stimulation Of

In cell-based therapies for cartilage lesions, the main problem is still the formation of fibrous cartilage, caused by underlying de-differentiation processes ex vivo. Biophysical stimulation is a promising approach to optimize cell-based procedures and to adapt them more closely to physiological conditions. The occurrence of mechano-electrical transduction phenomena within cartilage tissue is physiological and based on streaming and diffusion potentials. The application of exogenous electric fields can be used to mimic endogenous fields and, thus, support the differentiation of chondrocytes in vitro. For this purpose, we have developed a new device for electrical stimulation of chondrocytes, which operates on the basis of capacitive coupling of alternating electric fields. The reusable and sterilizable stimulation device allows the simultaneous use of 12 cavities with independently applicable fields using only one main supply. The first parameter settings for the stimulation of human non-degenerative chondrocytes, seeded on collagen type I elastin-based scaffolds, were derived from numerical electric field simulations. Our first results suggest that applied alternating electric fields induce chondrogenic re-differentiation at the gene and especially at the protein level of human de-differentiated chondrocytes in a frequency-dependent manner. In future studies, further parameter optimizations will be performed to improve the differentiation capacity of human cartilage cells.

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