scholarly journals Spike-timing-dependent BDNF secretion and synaptic plasticity

2014 ◽  
Vol 369 (1633) ◽  
pp. 20130132 ◽  
Author(s):  
Hui Lu ◽  
Hyungju Park ◽  
Mu-Ming Poo
Keyword(s):  
Hippocampal Neurons ◽  
Fluorescent Protein ◽  
Time Window ◽  
Hippocampal Slices ◽  
Long Term Potentiation ◽  
Spike Timing ◽  
Dependent Manner ◽  
Induced Responses ◽  
Before And After ◽  
Green Fluorescent

In acute hippocampal slices, we found that the presence of extracellular brain-derived neurotrophic factor (BDNF) is essential for the induction of spike-timing-dependent long-term potentiation (tLTP). To determine whether BDNF could be secreted from postsynaptic dendrites in a spike-timing-dependent manner, we used a reduced system of dissociated hippocampal neurons in culture. Repetitive pairing of iontophoretically applied glutamate pulses at the dendrite with neuronal spikes could induce persistent alterations of glutamate-induced responses at the same dendritic site in a manner that mimics spike-timing-dependent plasticity (STDP)—the glutamate-induced responses were potentiated and depressed when the glutamate pulses were applied 20 ms before and after neuronal spiking, respectively. By monitoring changes in the green fluorescent protein (GFP) fluorescence at the dendrite of hippocampal neurons expressing GFP-tagged BDNF, we found that pairing of iontophoretic glutamate pulses with neuronal spiking resulted in BDNF secretion from the dendrite at the iontophoretic site only when the glutamate pulses were applied within a time window of approximately 40 ms prior to neuronal spiking, consistent with the timing requirement of synaptic potentiation via STDP. Thus, BDNF is required for tLTP and BDNF secretion could be triggered in a spike-timing-dependent manner from the postsynaptic dendrite.

Resting Microglial Motility Is Independent of Synaptic Plasticity in Mammalian Brain

2008 ◽  
Vol 99 (4) ◽  
pp. 2026-2032 ◽  
Author(s):  
Long-Jun Wu ◽  
Min Zhuo
Keyword(s):  
Synaptic Plasticity ◽  
Brain Injuries ◽  
Fluorescent Protein ◽  
Hippocampal Slices ◽  
Time Lapse ◽  
Long Term Potentiation ◽  
Confocal Imaging ◽  
Mammalian Brain ◽  
Protective Function ◽  
Green Fluorescent

Microglia are well known for their roles in brain injuries and infections. However, there is no function attributes to resting microglia thus far. Here we performed a combination of simultaneous electrophysiology and time-lapse confocal imaging in green fluorescent protein–labeled microglia in acute hippocampal slices. In contrast to CA1 neurons, microglia showed no spontaneous or evoked synaptic currents. Neither glutamate- nor GABA-induced current/chemotaxis of microglia was detected. Strong tetanic stimulation of Schaffer-collateral pathways that induce CA1 long-term potentiation did not affect microglial motilities. Our results suggest that microglia are highly reserved for neuronal protective function but not synaptic plasticity in the brain.

scholarly journals Measles Virus Spreads in Rat Hippocampal Neurons by Cell-to-Cell Contact and in a Polarized Fashion

2002 ◽  
Vol 76 (11) ◽  
pp. 5720-5728 ◽  
Author(s):  
Markus U. Ehrengruber ◽  
Elisabeth Ehler ◽  
Martin A. Billeter ◽  
Hussein Y. Naim
Keyword(s):  
Hippocampal Neurons ◽  
Measles Virus ◽  
Matrix Protein ◽  
Fluorescent Protein ◽  
Subacute Sclerosing Panencephalitis ◽  
Hippocampal Slices ◽  
Pyramidal Cells ◽  
Cell Contact ◽  
F Protein ◽  
Green Fluorescent

ABSTRACT Measles virus (MV) can infect the central nervous system and, in rare cases, causes subacute sclerosing panencephalitis, characterized by a progressive degeneration of neurons. The route of MV transmission in neurons was investigated in cultured rat hippocampal slices by using MV expressing green fluorescent protein. MV infected hippocampal neurons and spread unidirectionally, in a retrograde manner, from CA1 to CA3 pyramidal cells and from there to the dentate gyrus. Spreading of infection depended on cell-to-cell contact and occurred without any detectable release of infectious particles. The role of the viral proteins in the retrograde MV transmission was determined by investigating their sorting in infected pyramidal cells. MV glycoproteins, the fusion protein (F) and hemagglutinin (H), the matrix protein (M), and the phosphoprotein (P), which is part of the viral ribonucleoprotein complex, were all sorted to the dendrites. While M, P, and H proteins remained more intracellular, the F protein localized to prominent, spine-type domains at the surface of infected cells. The detected localization of MV proteins suggests that local microfusion events may be mediated by the F protein at sites of synaptic contacts and is consistent with a mechanism of retrograde transmission of MV infection.

Abundant GFP Expression and LTP in Hippocampal Acute Slices by In Vivo Injection of Sindbis Virus

2001 ◽  
Vol 86 (2) ◽  
pp. 1037-1042 ◽  
Author(s):  
Massimo D'Apuzzo ◽  
Georgia Mandolesi ◽  
Gerald Reis ◽  
Erin M. Schuman
Keyword(s):  
Hippocampal Neurons ◽  
Sindbis Virus ◽  
Fluorescent Protein ◽  
Hippocampal Slices ◽  
Pyramidal Cells ◽  
Long Term Potentiation ◽  
Neuronal Structure ◽  
Adult Rats ◽  
Acute Hippocampal Slices

Virus-mediated gene transfer into neurons is a powerful tool for the analysis of neuronal structure and function. Recombinant sindbis virus has been previously used to study protein function in hippocampal neuron cultures as well as in hippocampal organotypic slice cultures. Nevertheless, some concern still exists about the physiological relevance of these cultured preparations. Acute hippocampal slices are a widely used preparation for the study of synaptic transmission, but currently recombinant gene delivery is usually achieved only through time-consuming transgenic techniques. In this study, we show that a subregion of the CA1 area in acute hippocampal slices can be specifically altered to express a gene of interest. A sindbis virus vector carrying an enhanced green fluorescent protein (EGFP) reporter was injected in vivo into the hippocampus of adult rats. After 18 h, rats were killed, and acute hippocampal slices, infected in the CA1 field, were analyzed morphologically and electrophysiologically. Infected slices showed healthy and stable electrophysiological responses as well as long-term potentiation. In addition, infected pyramidal cells were readily recognized in living slices by two-photon imaging. Specifically, the introduction of an EGFP-Actin fusion protein greatly enhanced the detection of fine processes and dendritic spines. We propose this technique as an efficient tool for studying gene function in adult hippocampal neurons.

scholarly journals Impairment of Spike-Timing-Dependent Plasticity at Schaffer Collateral-CA1 Synapses in Adult APP/PS1 Mice Depends on Proximity of Aβ Plaques

2021 ◽  
Vol 22 (3) ◽  
pp. 1378
Author(s):  
Machhindra Garad ◽  
Elke Edelmann ◽  
Volkmar Leßmann
Keyword(s):  
Neurodegenerative Disorder ◽  
Hippocampal Slices ◽  
Long Term Potentiation ◽  
Spike Timing ◽  
Dependent Manner ◽  
Spike Timing Dependent Plasticity ◽  
Schaffer Collateral ◽  
Ca1 Neurons ◽  
Dependent Plasticity ◽  
The Impact

Alzheimer’s disease (AD) is a multifaceted neurodegenerative disorder characterized by progressive and irreversible cognitive decline, with no disease-modifying therapy until today. Spike timing-dependent plasticity (STDP) is a Hebbian form of synaptic plasticity, and a strong candidate to underlie learning and memory at the single neuron level. Although several studies reported impaired long-term potentiation (LTP) in the hippocampus in AD mouse models, the impact of amyloid-β (Aβ) pathology on STDP in the hippocampus is not known. Using whole cell patch clamp recordings in CA1 pyramidal neurons of acute transversal hippocampal slices, we investigated timing-dependent (t-) LTP induced by STDP paradigms at Schaffer collateral (SC)-CA1 synapses in slices of 6-month-old adult APP/PS1 AD model mice. Our results show that t-LTP can be induced even in fully developed adult mice with different and even low repeat STDP paradigms. Further, adult APP/PS1 mice displayed intact t-LTP induced by 1 presynaptic EPSP paired with 4 postsynaptic APs (6× 1:4) or 1 presynaptic EPSP paired with 1 postsynaptic AP (100× 1:1) STDP paradigms when the position of Aβ plaques relative to recorded CA1 neurons in the slice were not considered. However, when Aβ plaques were live stained with the fluorescent dye methoxy-X04, we observed that in CA1 neurons with their somata <200 µm away from the border of the nearest Aβ plaque, t-LTP induced by 6× 1:4 stimulation was significantly impaired, while t-LTP was unaltered in CA1 neurons >200 µm away from plaques. Treatment of APP/PS1 mice with the anti-inflammatory drug fingolimod that we previously showed to alleviate synaptic deficits in this AD mouse model did not rescue the impaired t-LTP. Our data reveal that overexpression of APP and PS1 mutations in AD model mice disrupts t-LTP in an Aβ plaque distance-dependent manner, but cannot be improved by fingolimod (FTY720) that has been shown to rescue conventional LTP in CA1 of APP/PS1 mice.

A Modified Sindbis Vector for Prolonged Gene Expression in Neurons

2003 ◽  
Vol 90 (4) ◽  
pp. 2741-2745 ◽  
Author(s):  
Andreas Jeromin ◽  
Li-Lian Yuan ◽  
Andreas Frick ◽  
Paul Pfaffinger ◽  
Daniel Johnston
Keyword(s):  
Hippocampal Neurons ◽  
Fluorescent Protein ◽  
Time Window ◽  
Essential Gene ◽  
Functional Expression ◽  
Host Protein ◽  
Neuronal Structure ◽  
Voltage Gated Ion Channels ◽  
Green Fluorescent

Sindbis viruses have been widely used in neurobiology to express a variety of genes in cultured neurons, in cultured slices, and in vivo. They provide fast onset and high levels of expression of foreign genes, but the expression is limited to a short time window due to a shut-off of host protein synthesis. We have used a mutation in an essential gene (nsP2) of the life cycle of Sindbis, which allows the functional analysis of changes in protein expression for ≥6 days after infection. This Sindbis mutant (nsP2) was used to express enhanced green fluorescent protein (EGFP) in hippocampal neurons in culture and in vivo without any sign of toxicity, based on two-photon imaging and electrophysiology. In addition, the EGFP mutant virus can be injected in vivo to visualize spines and other details of neuronal structure. The Sindbis mutant described here provides an improved tool in neurobiology with reduced cytotoxicity and a prolonged time window of expression for novel applications in imaging and behavior. In addition, the use of this vector for the functional expression of mammalian voltage-gated ion channels in organotypic slices is demonstrated.

scholarly journals Extracellular Vesicles-Encapsulated Yeast Prions and What They Can Tell Us about the Physical Nature of Propagons

2020 ◽  
Vol 22 (1) ◽  
pp. 90
Author(s):  
Mehdi Kabani
Keyword(s):  
Protein Quality ◽  
Fluorescent Protein ◽  
Physical Nature ◽  
Dependent Manner ◽  
Yeast Saccharomyces Cerevisiae ◽  
Yeast Prions ◽  
Daughter Cells ◽  
Cytoplasmic Proteins ◽  
Green Fluorescent ◽  
Functionally Diverse

The yeast Saccharomyces cerevisiae hosts an ensemble of protein-based heritable traits, most of which result from the conversion of structurally and functionally diverse cytoplasmic proteins into prion forms. Among these, [PSI+], [URE3] and [PIN+] are the most well-documented prions and arise from the assembly of Sup35p, Ure2p and Rnq1p, respectively, into insoluble fibrillar assemblies. Yeast prions propagate by molecular chaperone-mediated fragmentation of these aggregates, which generates small self-templating seeds, or propagons. The exact molecular nature of propagons and how they are faithfully transmitted from mother to daughter cells despite spatial protein quality control are not fully understood. In [PSI+] cells, Sup35p forms detergent-resistant assemblies detectable on agarose gels under semi-denaturant conditions and cytosolic fluorescent puncta when the protein is fused to green fluorescent protein (GFP); yet, these macroscopic manifestations of [PSI+] do not fully correlate with the infectivity measured during growth by the mean of protein infection assays. We also discovered that significant amounts of infectious Sup35p particles are exported via extracellular (EV) and periplasmic (PV) vesicles in a growth phase and glucose-dependent manner. In the present review, I discuss how these vesicles may be a source of actual propagons and a suitable vehicle for their transmission to the bud.

scholarly journals GluA1 trafficking and metabotropic NMDA: addressing results from other laboratories inconsistent with ours

2014 ◽  
Vol 369 (1633) ◽  
pp. 20130145 ◽  
Author(s):  
Sadegh Nabavi ◽  
Rocky Fox ◽  
Stephanie Alfonso ◽  
Jonathan Aow ◽  
Roberto Malinow
Keyword(s):  
Fluorescent Protein ◽  
Long Term Potentiation ◽  
Long Term Depression ◽  
Mk 801 ◽  
Over Expression ◽  
Term Potentiation ◽  
The Difference ◽  
Green Fluorescent ◽  
Gfp Tag

We have previously shown that when over-expressed in neurons, green fluorescent protein (GFP) tagged GluA1 (GluA1-GFP) delivery into synapses is dependent on plasticity. A recent study suggests that GluA1 over-expression leads to its incorporation into the synapse, in the absence of additional long-term potentiation-like manipulations. It is possible that a GFP tag was responsible for the difference. Using rectification index as a measure of synaptic delivery of GluA1, we found no difference in the synaptic delivery of GluA1-GFP versus untagged GluA1. We recently published a study showing that while D-APV blocks NMDAr-dependent long-term depression (LTD), MK-801 and 7-chloro kynurenate (7CK) fail to block LTD. We propose a metabotropic function for the NMDA receptor in LTD induction. In contrast to our observations, recent unpublished data suggest that the above antagonists are equally effective in blocking LTD. We noticed different methodology in their study. Here, we show that their methodology has complex effects on synaptic transmission. Therefore, it is not possible to conclude that 7CK is effective in blocking LTD from their type of experiment.

scholarly journals Sequential neuromodulation of Hebbian plasticity offers mechanism for effective reward-based navigation

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Zuzanna Brzosko ◽  
Sara Zannone ◽  
Wolfram Schultz ◽  
Claudia Clopath ◽  
Ole Paulsen
Keyword(s):  
Time Window ◽  
Hippocampal Slices ◽  
Learning Rule ◽  
Spike Timing ◽  
Synaptic Potentiation ◽  
Behavioral Learning ◽  
Hebbian Plasticity ◽  
Subsequent Application ◽  
Behavioral States ◽  
Synaptic Learning

Spike timing-dependent plasticity (STDP) is under neuromodulatory control, which is correlated with distinct behavioral states. Previously, we reported that dopamine, a reward signal, broadens the time window for synaptic potentiation and modulates the outcome of hippocampal STDP even when applied after the plasticity induction protocol (Brzosko et al., 2015). Here, we demonstrate that sequential neuromodulation of STDP by acetylcholine and dopamine offers an efficacious model of reward-based navigation. Specifically, our experimental data in mouse hippocampal slices show that acetylcholine biases STDP toward synaptic depression, whilst subsequent application of dopamine converts this depression into potentiation. Incorporating this bidirectional neuromodulation-enabled correlational synaptic learning rule into a computational model yields effective navigation toward changing reward locations, as in natural foraging behavior. Thus, temporally sequenced neuromodulation of STDP enables associations to be made between actions and outcomes and also provides a possible mechanism for aligning the time scales of cellular and behavioral learning.

scholarly journals Changes in the Min Oscillation Pattern before and after Cell Birth

2010 ◽  
Vol 192 (16) ◽  
pp. 4134-4142 ◽  
Author(s):  
Jennifer R. Juarez ◽  
William Margolin
Keyword(s):  
Cell Division ◽  
Fluorescent Protein ◽  
Time Lapse ◽  
The Other ◽  
Cell Pole ◽  
Daughter Cells ◽  
Division Site ◽  
Before And After ◽  
Dividing Cells ◽  
Green Fluorescent

ABSTRACT The Min system regulates the positioning of the cell division site in many bacteria. In Escherichia coli, MinD migrates rapidly from one cell pole to the other. In conjunction with MinC, MinD helps to prevent unwanted FtsZ rings from assembling at the poles and to stabilize their positioning at midcell. Using time-lapse microscopy of growing and dividing cells expressing a gfp-minD fusion, we show that green fluorescent protein (GFP)-MinD often paused at midcell in addition to at the poles, and the frequency of midcell pausing increased as cells grew longer and cell division approached. At later stages of septum formation, GFP-MinD often paused specifically on only one side of the septum, followed by migration to the other side of the septum or to a cell pole. About the time of septum closure, this irregular pattern often switched to a transient double pole-to-pole oscillation in the daughter cells, which ultimately became a stable double oscillation. The splitting of a single MinD zone into two depends on the developing septum and is a potential mechanism to explain how MinD is distributed equitably to both daughter cells. Septal pausing of GFP-MinD did not require MinC, suggesting that MinC-FtsZ interactions do not drive MinD-septal interactions, and instead MinD recognizes a specific geometric, lipid, and/or protein target at the developing septum. Finally, we observed regular end-to-end oscillation over very short distances along the long axes of minicells, supporting the importance of geometry in MinD localization.

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