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Channelrhodopsin

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https://www.readbyqxmd.com/read/27908611/entorhinal-principal-neurons-mediate-brain-stimulation-treatments-for-epilepsy
#1
Zhenghao Xu, Yi Wang, Bin Chen, Cenglin Xu, Xiaohua Wu, Ying Wang, Shihong Zhang, Weiwei Hu, Shuang Wang, Yi Guo, Xiangnan Zhang, Jianhong Luo, Shumin Duan, Zhong Chen
Brain stimulation is an alternative treatment for epilepsy. However, the neuronal circuits underlying its mechanisms remain obscure. We found that optogenetic activation (1Hz) of entorhinal calcium/calmodulin-dependent protein kinase II α (CaMKIIα)-positive neurons, but not GABAergic neurons, retarded hippocampal epileptogenesis and reduced hippocampal seizure severity, similar to that of entorhinal low-frequency electrical stimulation (LFES). Optogenetic inhibition of entorhinal CaMKIIα-positive neurons blocked the antiepileptic effect of LFES...
November 23, 2016: EBioMedicine
https://www.readbyqxmd.com/read/27905012/microbial-proteins-as-novel-industrial-biotechnology-hosts-to-treat-epilepsy
#2
REVIEW
Zareen Amtul, Amal A Aziz
Epilepsy is characterized by the hyperexcitability of various neuronal circuits that results due to the imbalance between glutamate-mediated excitation of voltage-gated cation channels and γ-amino butyric acid (GABA)-mediated inhibition of anion channels leading to aberrant, sporadic oscillations or fluctuations in neuronal electrical activity. Epilepsy with a risk of mortality and around 65 million sufferers of all ages all over the world is limited therapeutically with high rates of adverse reactions, lack of complete seizure control, and over 30% patients with refractory epilepsy...
December 1, 2016: Molecular Neurobiology
https://www.readbyqxmd.com/read/27895984/fabrication-and-analysis-of-microfiber-array-platform-for-optogenetics-with-cellular-resolution
#3
Jian-Hong Chen, Ming-Yi Chou, Chien-Yuan Pan, Lon A Wang
Optogenetics has emerged as a revolutionary technology especially for neuroscience and has advanced continuously over the past decade. Conventional approaches for patterned in vivo optical illumination have a limitation on the implanted device size and achievable spatio-temporal resolution. In this work, we developed a fabrication process for a microfiber array platform. Arrayed poly(methyl methacrylate) (PMMA) microfibers were drawn from a polymer solution and packaged with polydimethylsiloxane (PDMS). The exposed end face of a packaged microfiber was tuned to have a size corresponding to a single cell...
November 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27884724/optogenetic-stimulation-of-glutamatergic-neuronal-activity-in-the-striatum-enhances-neurogenesis-in-the-subventricular-zone-of-normal-and-stroke-mice
#4
Mingke Song, Shan Ping Yu, Osama Mohamad, Wenyuan Cao, Zheng Zachory Wei, Xiaohuan Gu, Michael Qize Jiang, Ling Wei
Neurogenesis in the subventricular zone (SVZ) of the adult brain may contribute to tissue repair after brain injuries. Whether SVZ neurogenesis can be upregulated by specific neuronal activity in vivo and promote functional recovery after stroke is largely unknown. Using the spatial and cell type specific optogenetic technique combined with multiple approaches of in vitro, ex vivo and in vivo examinations, we tested the hypothesis that glutamatergic activation in the striatum could upregulate SVZ neurogenesis in the normal and ischemic brain...
November 21, 2016: Neurobiology of Disease
https://www.readbyqxmd.com/read/27861906/all-optical-functional-synaptic-connectivity-mapping-in-acute-brain-slices-using-campari
#5
Timothy A Zolnik, Fern Sha, Friedrich Johenning, Eric R Schreiter, Loren L Looger, Matthew E Larkum, Robert N S Sachdev
The calcium-modulated photoactivatable ratiometric integrator CaMPARI (Fosque et al., 2015) facilitates the study of neural circuits by permanently marking cells active during user-specified temporal windows. Permanent marking enables measurement of signals from large swathes of tissue and easy correlation of activity with other structural or functional labels. One potential application of CaMPARI is labeling neurons postsynaptic to specific populations targeted for optogenetic stimulation, giving rise to all-optical functional connectivity mapping...
November 11, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27844060/serotonergic-suppression-of-mouse-prefrontal-circuits-implicated-in-task-attention
#6
Michael K Tian, Eric F Schmidt, Evelyn K Lambe
Serotonin (5-HT) regulates attention by neurobiological mechanisms that are not well understood. Layer 6 (L6) pyramidal neurons of prefrontal cortex play an important role in attention and express 5-HT receptors, but the serotonergic modulation of this layer and its excitatory output is not known. Here, we performed whole-cell recordings and pharmacological manipulations in acute brain slices from wild-type and transgenic mice expressing either eGFP or eGFP-channelrhodopsin in prefrontal L6 pyramidal neurons...
September 2016: ENeuro
https://www.readbyqxmd.com/read/27810932/activity-dependent-dynamics-of-the-transcription-factor-creb-in-cortical-neurons-revealed-by-single-molecule-imaging
#7
Hironobu Kitagawa, Noriyuki Sugo, Masatoshi Morimatsu, Yoshiyuki Arai, Toshio Yanagida, Nobuhiko Yamamoto
: Transcriptional regulation is crucial for neuronal activity-dependent processes that govern neuronal circuit formation and synaptic plasticity. An intriguing question is how neuronal activity influences the spatiotemporal interactions between transcription factors and their target sites. Here we investigated the activity dependence of DNA binding and dissociation events of cAMP-response element binding protein (CREB), a principal factor in activity-dependent transcription, in mouse cortical neurons using a single-molecule imaging technique...
November 3, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27809305/chronic-activation-of-the-d156a-point-mutant-of-channelrhodopsin-2-signals-apoptotic-cell-death-the-good-and-the-bad
#8
Michael Perny, Lukas Muri, Heather Dawson, Sonja Kleinlogel
Channelrhodopsin-2 (ChR2) has become a celebrated research tool and is considered a promising potential therapeutic for neurological disorders. While making its way into the clinic, concerns about the safety of chronic ChR2 activation have emerged; in particular as the high-intensity blue light illumination needed for ChR2 activation may be phototoxic. Here we set out to quantify for the first time the cytotoxic effects of chronic ChR2 activation. We studied the safety of prolonged illumination on ChR2(D156A)-expressing human melanoma cells as cancer cells are notorious for their resistance to killing...
November 3, 2016: Cell Death & Disease
https://www.readbyqxmd.com/read/27798186/genetically-targeted-all-optical-electrophysiology-with-a-transgenic-cre-dependent-optopatch-mouse
#9
Shan Lou, Yoav Adam, Eli N Weinstein, Erika Williams, Katherine Williams, Vicente Parot, Nikita Kavokine, Stephen Liberles, Linda Madisen, Hongkui Zeng, Adam E Cohen
: Recent advances in optogenetics have enabled simultaneous optical perturbation and optical readout of membrane potential in diverse cell types. Here, we develop and characterize a Cre-dependent transgenic Optopatch2 mouse line that we call Floxopatch. The animals expressed a blue-shifted channelrhodopsin, CheRiff, and a near infrared Archaerhodopsin-derived voltage indicator, QuasAr2, via targeted knock-in at the rosa26 locus. In Optopatch-expressing animals, we tested for overall health, genetically targeted expression, and function of the optogenetic components...
October 26, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27789708/in-vitro-activity-of-a-purified-natural-anion-channelrhodopsin
#10
Hai Li, Oleg A Sineshchekov, Gang Wu, John L Spudich
Natural anion channelrhodopsins (ACRs) recently discovered in cryptophyte algae are the most active rhodopsin channels known. They are of interest both because of their unique natural function of light-gated chloride conductance and because of their unprecedented efficiency of membrane hyperpolarization for optogenetic neuron silencing. Light-induced currents of ACRs have been studied in HEK cells and neurons, but light-gated channel conductance of ACRs in vitro has not been demonstrated. Here we report light-induced chloride channel activity of a purified ACR protein reconstituted in large unilamellar vesicles (LUVs)...
December 2, 2016: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/27786307/coupling-optogenetic-stimulation-with-nanoluc-based-luminescence-bret-ca-sensing
#11
Jie Yang, Derrick Cumberbatch, Samuel Centanni, Shu-Qun Shi, Danny Winder, Donna Webb, Carl Hirschie Johnson
Optogenetic techniques allow intracellular manipulation of Ca(++) by illumination of light-absorbing probe molecules such as channelrhodopsins and melanopsins. The consequences of optogenetic stimulation would optimally be recorded by non-invasive optical methods. However, most current optical methods for monitoring Ca(++) levels are based on fluorescence excitation that can cause unwanted stimulation of the optogenetic probe and other undesirable effects such as tissue autofluorescence. Luminescence is an alternate optical technology that avoids the problems associated with fluorescence...
October 27, 2016: Nature Communications
https://www.readbyqxmd.com/read/27768773/optochemokine-tandem-for-light-control-of-intracellular-ca2
#12
Katrin Feldbauer, Jan Schlegel, Juliane Weissbecker, Frank Sauer, Phillip G Wood, Ernst Bamberg, Ulrich Terpitz
An optochemokine tandem was developed to control the release of calcium from endosomes into the cytosol by light and to analyze the internalization kinetics of G-protein coupled receptors (GPCRs) by electrophysiology. A previously constructed rhodopsin tandem was re-engineered to combine the light-gated Ca2+-permeable cation channel Channelrhodopsin-2(L132C), CatCh, with the chemokine receptor CXCR4 in a functional tandem protein tCXCR4/CatCh. The GPCR was used as a shuttle protein to displace CatCh from the plasma membrane into intracellular areas...
2016: PloS One
https://www.readbyqxmd.com/read/27740714/optogenetic-excitation-in-the-ventral-tegmental-area-of-glutamatergic-or-cholinergic-inputs-from-the-laterodorsal-tegmental-area-drives-reward
#13
Stephan Steidl, Huiling Wang, Marco Ordonez, Shiliang Zhang, Marisela Morales
Converging evidence shows that ventral tegmental area (VTA) dopamine neurons receive laterodorsal tegmental nucleus (LDTg) cholinergic and glutamatergic inputs. To test the behavioral consequences of selectively driving the two sources of excitatory LDTg input to the VTA, channelrhodopsin-2 (ChR2) was expressed in LDTg cholinergic neurons of ChAT::Cre mice (ChAT-ChR2 mice) or in LDTg glutamatergic neurons of VGluT2::Cre mice (VGluT2-ChR2 mice). Mice were tested in a 3-chamber place preference apparatus where entry into a light-paired chamber resulted in VTA light stimulation of LDTg-cholinergic or LDTg-glutamatergic axons for the duration of a chamber stay...
October 14, 2016: European Journal of Neuroscience
https://www.readbyqxmd.com/read/27734925/an-optogenetic-demonstration-of-motor-modularity-in-the-mammalian-spinal-cord
#14
Vittorio Caggiano, Vincent C K Cheung, Emilio Bizzi
Motor modules are neural entities hypothesized to be building blocks of movement construction. How motor modules are underpinned by neural circuits has remained obscured. As a first step towards dissecting these circuits, we optogenetically evoked motor outputs from the lumbosacral spinal cord of two strains of transgenic mice - the Chat, with channelrhodopsin (ChR2) expressed in motoneurons, and the Thy1, expressed in putatively excitatory neurons. Motor output was represented as a spatial field of isometric ankle force...
October 13, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27699114/automated-highly-reproducible-wide-field-light-based-cortical-mapping-method-using-a-commercial-stereo-microscope-and-its-applications
#15
Su Jiang, Ya-Feng Liu, Xiao-Min Wang, Ke-Fei Liu, Ding-Hong Zhang, Yi-Ding Li, Ai-Ping Yu, Xiao-Hui Zhang, Jia-Yi Zhang, Jian-Guang Xu, Yu-Dong Gu, Wen-Dong Xu, Shao-Qun Zeng
We introduce a more flexible optogenetics-based mapping system attached on a stereo microscope, which offers automatic light stimulation to individual regions of interest in the cortex that expresses light-activated channelrhodopsin-2 in vivo. Combining simultaneous recording of electromyography from specific forelimb muscles, we demonstrate that this system offers much better efficiency and precision in mapping distinct domains for controlling limb muscles in the mouse motor cortex. Furthermore, the compact and modular design of the system also yields a simple and flexible implementation to different commercial stereo microscopes, and thus could be widely used among laboratories...
September 1, 2016: Biomedical Optics Express
https://www.readbyqxmd.com/read/27698240/combining-optogenetics-and-electrophysiology-to-analyze-projection-neuron-circuits
#16
Naoki Yamawaki, Benjamin A Suter, Ian R Wickersham, Gordon M G Shepherd
A set of methods is described for channelrhodopsin-2 (ChR2)-based synaptic circuit analysis that combines photostimulation of virally transfected presynaptic neurons' axons with whole-cell electrophysiological recordings from retrogradely labeled postsynaptic neurons. The approach exploits the preserved photoexcitability of ChR2-expressing axons in brain slices and can be used to assess either local or long-range functional connections. Stereotaxic injections are used both to express ChR2 selectively in presynaptic axons of interest (using rabies virus [RV] or adeno-associated virus [AAV]) and to label two types of postsynaptic projection neurons of interest with fluorescent retrograde tracers...
October 3, 2016: Cold Spring Harbor Protocols
https://www.readbyqxmd.com/read/27693474/direct-projections-from-hypothalamic-orexin-neurons-to-brainstem-cardiac-vagal-neurons
#17
Olga Dergacheva, Akihiro Yamanaka, Alan R Schwartz, Vsevolod Y Polotsky, David Mendelowitz
Orexin neurons are known to augment the sympathetic control of cardiovascular function, however the role of orexin neurons in parasympathetic cardiac regulation remains unclear. To test the hypothesis that orexin neurons contribute to parasympathetic control we selectively expressed channelrhodopsin-2 (ChR2) in orexin neurons in orexin-Cre transgenic rats and examined postsynaptic currents in cardiac vagal neurons (CVNs) in the dorsal motor nucleus of the vagus (DMV). Simultaneous photostimulation and recording in ChR2-expressing orexin neurons in the lateral hypothalamus resulted in reliable action potential firing as well as large whole-cell currents suggesting a strong expression of ChR2 and reliable optogenetic excitation...
December 17, 2016: Neuroscience
https://www.readbyqxmd.com/read/27682165/the-road-to-optogenetics-microbial-rhodopsins
#18
REVIEW
E G Govorunova, L A Koppel
Optogenetics technology (using light-sensitive microbial proteins to control animal cell physiology) is becoming increasingly popular in laboratories around the world. Among these proteins, particularly important are rhodopsins that transport ions across the membrane and are used in optogenetics to regulate membrane potential by light, mostly in neurons. Although rhodopsin ion pumps transport only one charge per captured photon, channelrhodopsins are capable of more efficient passive transport. In this review, we follow the history of channelrhodopsin discovery in flagellate algae and discuss the latest addition to the channelrhodopsin family, channels with anion, rather than cation, selectivity...
September 2016: Biochemistry. Biokhimii︠a︡
https://www.readbyqxmd.com/read/27679671/red-shifted-channelrhodopsin-stimulation-restores-light-responses-in-blind-mice-macaque-retina-and-human-retina
#19
Abhishek Sengupta, Antoine Chaffiol, Emilie Macé, Romain Caplette, Mélissa Desrosiers, Maruša Lampič, Valérie Forster, Olivier Marre, John Y Lin, José-Alain Sahel, Serge Picaud, Deniz Dalkara, Jens Duebel
Targeting the photosensitive ion channel channelrhodopsin-2 (ChR2) to the retinal circuitry downstream of photoreceptors holds promise in treating vision loss caused by retinal degeneration. However, the high intensity of blue light necessary to activate channelrhodopsin-2 exceeds the safety threshold of retinal illumination because of its strong potential to induce photochemical damage. In contrast, the damage potential of red-shifted light is vastly lower than that of blue light. Here, we show that a red-shifted channelrhodopsin (ReaChR), delivered by AAV injections in blind rd1 mice, enables restoration of light responses at the retinal, cortical, and behavioral levels, using orange light at intensities below the safety threshold for the human retina...
September 27, 2016: EMBO Molecular Medicine
https://www.readbyqxmd.com/read/27650332/dampening-spontaneous-activity-improves-the-light-sensitivity-and-spatial-acuity-of-optogenetic-retinal-prosthetic-responses
#20
John Martin Barrett, Gerrit Hilgen, Evelyne Sernagor
Retinitis pigmentosa is a progressive retinal dystrophy that causes irreversible visual impairment and blindness. Retinal prostheses currently represent the only clinically available vision-restoring treatment, but the quality of vision returned remains poor. Recently, it has been suggested that the pathological spontaneous hyperactivity present in dystrophic retinas may contribute to the poor quality of vision returned by retinal prosthetics by reducing the signal-to-noise ratio of prosthetic responses. Here, we investigated to what extent blocking this hyperactivity can improve optogenetic retinal prosthetic responses...
September 21, 2016: Scientific Reports
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