Name: construction of cell-based neurotransmitter fluorescent engineered reporters (cnifers) for optical detection of neurotransmitters in vivo
Uploaded: 2016-05-12T13:00:00
Description: Watch this Scientific Journal Video about Construction of Cell-based Neurotransmitter Fluorescent Engineered Reporters CNiFERs for Optical Detection of Neurotransmitters In Vivo at JoVE.com

We thank B. Conklin (University of California, San Francisco) for providing the Gqi5 and Gqs5 cDNAs, A. Schweitzer for assistance with the electronics, N. Taylor for assistance with screening of clones, Ian Glaaser and Robert Rifkin for proof reading, and Olivier Griesbeck for TN-XXL. This work was supported by research grants through the US National Institute on Drug Abuse (NIDA) (DA029706; DA037170), the National Institute of Biomedical Imaging and Bioengineering (NIBIB) (EB003832), Hoffman-La Roche (88610A) and the &#34;Neuroscience Related to Drugs of Abuse&#34; training grant through NIDA (DA007315).

All animal procedures performed in this study are in accordance with Institutional Animal Care and Use Committee (IACUC) guidelines, and have been approved by the IACUCs at the Icahn School of Medicine at Mount Sinai and the University of California, San Diego.
1. Generate GPCR-expressing Lentivirus for Transforming HEK293 Cells
<ol>
	<li>Obtain the cDNA for a specific GPCR from a commercial source, e.g., cdna.org. Alternatively, amplify the GPCR gene from a cDNA library using PCR. Obtain a lentivirus-e...

<ol>
	<li>Day, J. C., Kornecook, T. J., Quirion, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+in+vivo.+microdialysis+to+the+study+of+cholinergic+systems.">Application of in vivo. microdialysis to the study of cholinergic systems.</a> Methods. 23, 21-39 (2001).</li><li>Robinson, D. L., Venton, B. J., Heien, M. L., Wightman, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detecting+subsecond+dopamine+release+with+fast-scan+cyclic+voltammetry+in+vivo.">Detecting subsecond dopamine release with fast-scan cyclic voltammetry in vivo.</a> Clin Chem. 49, 1763-1773 (2003).</li><li>Liang, R., Broussard, G. J., Tian, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+Chemical+Neurotransmission+with+Genetically+Encoded+Fluorescent+Sensors.">Imaging Chemical Neurotransmission with Genetically Encoded Fluorescent Sensors.</a> ACS Chem Neurosci. , (2015).</li><li>Okubo, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imaging+extrasynaptic+glutamate+dynamics+in+the+brain.">Imaging extrasynaptic glutamate dynamics in the brain.</a> Proc. Natl. Acad. Sci. USA. 107, 6526-6531 (2010).</li><li>Marvin, J. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+optimized+fluorescent+probe+for+visualizing+glutamate+neurotransmission.">An optimized fluorescent probe for visualizing glutamate neurotransmission.</a> Nat Methods. 10, 162-170 (2013).</li><li>Nguyen, Q. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vivo+biosensor+for+neurotransmitter+release+and+in+situ+receptor+activity.">An in vivo biosensor for neurotransmitter release and in situ receptor activity.</a> Nat Neurosci. 13, 127-132 (2010).</li><li>Muller, A., Joseph, V., Slesinger, P. A., Kleinfeld, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell-based+reporters+reveal+in+vivo+dynamics+of+dopamine+and+norepinephrine+release+in+murine+cortex.">Cell-based reporters reveal in vivo dynamics of dopamine and norepinephrine release in murine cortex.</a> Nat Methods. 11, 1245-1252 (2014).</li><li>Lorenz, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymerase+chain+reaction:+basic+protocol+plus+troubleshooting+and+optimization+strategies.">Polymerase chain reaction: basic protocol plus troubleshooting and optimization strategies.</a> J Vis Exp. , e3998 (2012).</li><li>Wang, X., McManus, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lentivirus+production.">Lentivirus production.</a> J Vis Exp. , (2009).</li><li>Conklin, B. R., Farfel, Z., Lustig, K. D., Julius, D., Bourne, H. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Substitution+of+three+amino+acids+switches+receptor+specificity+of+Gq&#945;+to+that+of+Gj&#945;.">Substitution of three amino acids switches receptor specificity of Gq&#945; to that of Gj&#945;.</a> Nature. 363, 274-276 (1993).</li><li>Cetin, A., Komai, S., Eliava, M., Seeburg, P. H., Osten, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereotaxic+gene+delivery+in+the+rodent+brain.">Stereotaxic gene delivery in the rodent brain.</a> Nat Protoc. 1, 3166-3173 (2006).</li><li>Shih, A. Y., Mateo, C., Drew, P. J., Tsai, P. S., Kleinfeld, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+polished+and+reinforced+thinned-skull+window+for+long-term+imaging+of+the+mouse+brain.">A polished and reinforced thinned-skull window for long-term imaging of the mouse brain.</a> J Vis Exp. , (2012).</li><li>Drew, P. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chronic+optical+access+through+a+polished+and+reinforced+thinned+skull.">Chronic optical access through a polished and reinforced thinned skull.</a> Nat Methods. 7, 981-984 (2010).</li><li>Shih, A. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-photon+microscopy+as+a+tool+to+study+blood+flow+and+neurovascular+coupling+in+the+rodent+brain.">Two-photon microscopy as a tool to study blood flow and neurovascular coupling in the rodent brain.</a> J Cereb Blood Flow Metab. 32, 1277-1309 (2012).</li><li>Yamauchi, J. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterizing+ligand-gated+ion+channel+receptors+with+genetically+encoded+Ca2++sensors.">Characterizing ligand-gated ion channel receptors with genetically encoded Ca2+ sensors.</a> PLoS One. 6, e16519 (2011).</li><li>Akerboom, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+a+GCaMP+calcium+indicator+for+neural+activity+imaging.">Optimization of a GCaMP calcium indicator for neural activity imaging.</a> J. Neurosci. 32, 13819-13840 (2012).</li><li>Helmchen, F., Denk, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deep+tissue+two-photon+microscopy.">Deep tissue two-photon microscopy.</a> Nat Methods. 2, 932-940 (2005).</li><li>Svoboda, K., Yasuda, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Principles+of+two-photon+excitation+microscopy+and+its+applications+to+neuroscience.">Principles of two-photon excitation microscopy and its applications to neuroscience.</a> Neuron. 50, 823-839 (2006).</li><li>Cui, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concurrent+activation+of+striatal+direct+and+indirect+pathways+during+action+initiation.">Concurrent activation of striatal direct and indirect pathways during action initiation.</a> Nature. 494, 238-242 (2013).</li></ol>

The creation of CNiFERs provides an innovative and unique strategy for optically measuring release of neurotransmitters in the brain in vivo. CNiFERs are ideally suited for measuring extrasynaptic release, i.e., volume conduction, for neurotransmitters. Importantly, each CNiFER possesses the properties of the native GPCR, providing a physiological optical measurement of the changes in levels of neurotransmitters in the brain. To date, CNiFERs have been created for detecting acetylcholine (M1-CNiFER)<sup...

To fully understand how neurons communicate in the brain, it is necessary to have a method to measure the release of neurotransmitters in vivo. There are several well-established techniques for measuring neurotransmitters in vivo. One commonly used technique is microdialysis, in which a cannula is inserted into the brain and a small volume of cerebrospinal fluid is collected and analyzed using high-performance liquid chromatography and electrochemical detection1. Microdialysis has a spatial resolution on the order of a few diameters of the probe, e.g., ~0.5 mm for a 200 &#956;m diameter microprobe. The temporal resolution of this technique, however, is slow due to sampling intervals that typically last ~5 min or longer1. Moreover, analyses are not made in real-time. Another technique is fast scanning cyclic voltammetry (FSCV), which uses a carbon-fiber probe that is inserted into the brain. FSCV has excellent temporal resolution (subsecond), high sensitivity (nanomolar), and spatial resolution with probe&#160;diameters of 5 to 30 &#956;m. However, FSCV is limited to transmitters that produce a characteristic oxidation and reduction profile with voltage on a carbon potentiometric probe2.
A third technique to measure neurotransmitters is directly through genetically-encoded neurotransmitter (NT) biosensors3. With this method, a fusion protein is created that contains a ligand-binding domain for a transmitter coupled to a fluorescence resonance energy transfer (FRET)-based pair of fluorophores4 or a permutated GFP5. Unlike the previous two methods, these biosensors are genetically encoded and expressed on the surface of a host cell, such as a neuron, through the production of transgenic animals or acutely with the use of viral agents to infect cells. To date, genetically-encoded biosensors have been only developed for detecting glutamate and GABA3-5. Limitations with these techniques have been the low sensitivity, in the nM range,&#160;and the inability to expand the detection to the large number of transmitters, e.g., classical neurotransmitters, neuropeptides and neuromodulators, which signal through G protein-coupled receptors (GPCRs). In fact, there are nearly 800 GPCRs in the human genome.
To address these shortfalls, we have developed an innovative tool to optically measure release of any neurotransmitter that signals through a GPCR. CNiFERs (cell-based neurotransmitter fluorescent engineered reporters) are clonal HEK293 cells engineered to express a specific GPCR that, when stimulated, triggers an increase in intracellular [Ca2+] that is detected by a genetically encoded FRET-based Ca2+ sensor, TN-XXL. Thus, CNiFERs transform neurotransmitter receptor binding into a change in fluorescence, providing a direct and real-time optical read-out of local neurotransmitter activity. By utilizing the native receptor for a given neurotransmitter, CNiFERs retain the chemical specificity, affinity and temporal dynamics of the endogenously expressed receptors. To date, we have created three types of CNiFERs, one for detecting acetylcholine using the M1 receptor, one for detecting dopamine using the D2 receptor, and one for detecting norepinephrine using the &#945;1a receptor6,7. The CNiFER technology is readily expandable and scalable, making it amenable to any type of GPCR. In this JoVE article, we describe and illustrate the methodology to design, realize, and test in vivo CNiFERs for any application.

<table border="0" cellpadding="0" cellspacing="0" width="1212">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">pCDH-CMV-MCS-EF1-Puro&#160;</td>
			<td style="width:191px;">System Biosciences</td>
			<td style="width:429px;">CD510B-1</td>
			<td style="width:207px;">Cloning: for generating lentivirus</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">12x75 *BD Falcon High Clarity Polypropylene Round Bottom Test Tube</td>
			<td style="width:191px;">BD Biosciences</td>
			<td>352063</td>
			<td>FACS</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">BD 40 um Falcon cell strainers</td>
			<td style="width:191px;">BD Biosciences</td>
			<td>352340</td>
			<td>FACS</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">0.05% Trypsin EDTA&#160;</td>
			<td style="width:191px;">Invitrogen</td>
			<td>25200056</td>
			<td>FACS</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">96 Well Plate, flat bottom, clear&#160;</td>
			<td>Corning&#160;</td>
			<td>3596</td>
			<td>FACS</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">96 well cell culture plates&#160;</td>
			<td>Corning&#160;</td>
			<td>CLS3997</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Optilux black clear bottom&#160;</td>
			<td>Corning&#160;</td>
			<td>3603</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Flexstation pipet tips</td>
			<td style="width:191px;">Molecular Devices</td>
			<td>9000-0911</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Acetylcholine Chloride&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">A2661</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Norepinephrine&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">A7256</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Dopamine Hydrochloride&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">PHR1090</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">GABA&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">A2129</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Histamine&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">H7125</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Glutamate&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">49621</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Epinephrine&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">E4642</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Somatostatin&#160;&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">S1763</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">5HT&#160;&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">H9523</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">VIP&#160;</td>
			<td style="width:191px;">Alpha Diagnostics Inc.&#160;&#160;&#160;</td>
			<td style="width:429px;">SP-69627</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Orexin A</td>
			<td style="width:191px;">Alpha Diagnostics Inc.&#160;&#160;&#160;</td>
			<td style="width:429px;">12-p-01</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Substance P&#160;&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">S6883</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Adenosine</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">A4036</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Melatonin&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">M5250C</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">Fluorescence Plate Reader &#38; software</td>
			<td style="width:191px;">Molecular Devices</td>
			<td style="width:429px;">Flexstation 3</td>
			<td>Flexstation</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;"></td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;"></td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">&#160;DMEM (high glucose) with Glutamax&#160;&#160;</td>
			<td style="width:191px;">Life Technologies</td>
			<td style="width:429px;">10569-010</td>
			<td>Tissue culture</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">&#160;Fetal bovine serum</td>
			<td style="width:191px;">Life Technologies</td>
			<td style="width:429px;">10082-139</td>
			<td>Tissue culture</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">&#160;Pen/Strep&#160;</td>
			<td style="width:191px;">Life Technologies</td>
			<td style="width:429px;">15140-122</td>
			<td>Tissue culture</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">&#160;Puromycin&#160;&#160;</td>
			<td style="width:191px;">InvivoGen</td>
			<td style="width:429px;">ant-pr-1</td>
			<td>Tissue culture</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">&#160;Fibronectin&#160;</td>
			<td style="width:191px;">SimgaAldrich</td>
			<td style="width:429px;">F0895</td>
			<td>Tissue culture</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:387px;">CoolCell LX Alcohol-free controlled-rate cell freezing box</td>
			<td style="width:191px;">Bioexpress</td>
			<td style="width:429px;">D-3508)</td>
			<td>Tissue culture</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;"></td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">cyanoacrylate glue&#160;</td>
			<td style="width:191px;">Loctite</td>
			<td style="width:429px;">Loctite no. 495</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">plastic paraffin film&#160;</td>
			<td style="width:191px;">VWR</td>
			<td style="width:429px;">Parafilm&#174;</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">NANOINJECTOR</td>
			<td style="width:191px;">Drummond</td>
			<td style="width:429px;">3-000-204</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">GLASS ELECTRODES</td>
			<td style="width:191px;">Drummond</td>
			<td style="width:429px;">3-000-203G</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">hand held drill</td>
			<td style="width:191px;">OSADA</td>
			<td style="width:429px;">Exl-M40</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Burrs for drill</td>
			<td style="width:191px;">Fine Scientific</td>
			<td style="width:429px;">19007-05; 19007-07)</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">Sterilizing bath</td>
			<td style="width:191px;">FST</td>
			<td style="width:429px;">18000-45, Hot Bead Sterilizer</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:387px;">isoflurane chamber/mask</td>
			<td style="width:191px;">Highland Medical Equipment</td>
			<td style="width:429px;">564-0427, HME 109 Table Top Anesthetic Machine with Isoflurane Vaporizer, O2 Flowmeter, Gang Valve; 564-0852, Induction Chamber 16X7X7.5cm</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">3D scope with arm</td>
			<td style="width:191px;">Zeiss</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">fiber optic light</td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Betadine&#160;</td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">70 % (v/v) isopropyl alcohol</td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Povidone-Iodine Prep Pads</td>
			<td style="width:191px;">dynarex</td>
			<td style="width:429px;">1108</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">NaCl 0.9% (INJECTION, USP, 918610)</td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">CYCLOSPORINE (INJECTION, USP)</td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Buprenex (INJECTION) buprenorphine (0.03 &#956;g per g rodent)</td>
			<td style="width:191px;">Sigma</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Ophthalmic ointment&#160;</td>
			<td style="width:191px;">Akorn</td>
			<td style="width:429px;">NDC 17478-235-35</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Surgifoam</td>
			<td style="width:191px;">Ethicon</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Grip dental cement</td>
			<td style="width:191px;">Dentsply</td>
			<td style="width:429px;">#675571, 675572</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Instant SuperGlue&#160;</td>
			<td style="width:191px;">NDindustries</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">LOCTITE 4041</td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">METABOND</td>
			<td style="width:191px;">C&#38;B</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">no. 0 cover glass</td>
			<td style="width:191px;">Fisher</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">stereotaxic frame&#160;</td>
			<td style="width:191px;">Kopf</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;">Rectal probe and heating pad</td>
			<td style="width:191px;">FHC</td>
			<td style="width:429px;">40-90-8D, DC Temperature Controller,40-90-2-06, 6.5X9.5cm Heating Pad40-90-5D-02, Rectal Thermistor Probe</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">optical breadboard for imaging</td>
			<td style="width:191px;">Thorlabs</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Mineral oil</td>
			<td style="width:191px;">Fisher</td>
			<td style="width:429px;">S55667</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Kwik-Cast (Silicone elastomer)</td>
			<td style="width:191px;">World Precision Instruments</td>
			<td style="width:429px;"></td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Suture&#160;&#160;</td>
			<td style="width:191px;">Ethicon</td>
			<td style="width:429px;">18&#8217;&#8217;, 1667, 4-0</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Scissors</td>
			<td style="width:191px;">Fine Scientific Tools</td>
			<td style="width:429px;">91500-09, 15018-10</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Forcepts</td>
			<td style="width:191px;">Fine Scientific Tools</td>
			<td style="width:429px;">11252-30; #55, 11295-51; Grafe, 11050-10</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Student Halsted-Mosquito Hemostats</td>
			<td style="width:191px;">Fine Scientific Tools</td>
			<td style="width:429px;">91308-12</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Small Vessel Cauterizer Kit</td>
			<td style="width:191px;">Fine Scientific Tools</td>
			<td style="width:429px;">18000-00</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Hot Bead Sterilizers</td>
			<td style="width:191px;">Fine Scientific Tools</td>
			<td style="width:429px;">18000-45</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Instrument Case with Silicone Mat</td>
			<td style="width:191px;">Fine Scientific Tools</td>
			<td style="width:429px;">20311-21</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Plastic Sterilization Containers with Silicone Mat</td>
			<td style="width:191px;">Fine Scientific Tools</td>
			<td style="width:429px;">20810-01</td>
			<td>surgery and stereotaxic injection</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;"></td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;"></td>
			<td style="width:191px;"></td>
			<td style="width:429px;"></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:387px;">2P fixed-stage fluorescence scope for in vivo imaging</td>
			<td style="width:191px;">Olympus</td>
			<td style="width:429px;">FV1200 MPE</td>
			<td>in vivo imaging</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">Multiphoton laser</td>
			<td style="width:191px;">SpectraPhysics</td>
			<td style="width:429px;">Mai Tai DeepSee</td>
			<td>in vivo imaging</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">Green Laser</td>
			<td style="width:191px;">Olympus</td>
			<td style="width:429px;">473 nm Laser</td>
			<td>in vivo imaging</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">xy translation base</td>
			<td style="width:191px;">Scientifica</td>
			<td style="width:429px;">MMBP</td>
			<td>in vivo imaging</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">FRET filter cube for YFP and CFP</td>
			<td style="width:191px;">Olympus</td>
			<td style="width:429px;"></td>
			<td>in vivo imaging</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">25-X water immersion objective</td>
			<td style="width:191px;">Olympus</td>
			<td style="width:429px;"></td>
			<td>in vivo imaging</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">air table</td>
			<td style="width:191px;">Newport</td>
			<td style="width:429px;"></td>
			<td>in vivo imaging</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:387px;">custom built light-tight cage</td>
			<td style="width:191px;">Thorlab</td>
			<td style="width:429px;"></td>
			<td>in vivo imaging</td>
		</tr>
	</tbody>
</table>

construction of cell-based neurotransmitter fluorescent engineered reporters (cnifers) for optical detection of neurotransmitters in vivo

Cell-based neurotransmitter fluorescent engineered reporters (CNiFERs) provide a new tool for neuroscientists to optically detect the release of neurotransmitters in the brain in vivo. A specific CNiFER is created from a human embryonic kidney cell that stably expresses a specific G protein-coupled receptor, which couples to Gq/11 G proteins, and a FRET-based Ca2+-detector, TN-XXL. Activation of the receptor leads to an increase in the FRET signal. CNiFERs have nM sensitivity and a temporal response of seconds because a CNiFER clone utilizes the native receptor for a particular neurotransmitter, e.g., D2R for dopamine. CNiFERs are directly implanted into the brain, enabling them to sense neurotransmitter release with a spatial resolution of less than one hundred &#181;m, making them ideal to measure volume transmission in vivo. CNiFERs can also be used to screen other drugs for potential cross-reactivity in vivo. We recently expanded the family of CNiFERs to include GPCRs that couple to Gi/o G proteins. CNiFERs are available for detecting acetylcholine (ACh), dopamine (DA) and norepinephrine (NE). Given that any GPCR can be used to create a novel CNiFER and that there are approximately 800 GPCRs in the human genome, we describe here the general procedure to design, realize, and test any type of CNiFER.

A CNiFER is derived from a human embryonic kidney (HEK293) cell that is engineered to stably express at least two proteins: a specific G-protein coupled receptor (GPCR) and a genetically encoded [Ca2+] sensor, TN-XXL. TN-XXL undergoes fluorescence resonance energy transfer (FRET) between cyan and yellow fluorescent proteins, eCFP and Citrine, respectively, in response to Ca2+ ions6,15. Activation of GPCRs that couple to endogenous Gq G proteins ...

Watch this Scientific Journal Video about Construction of Cell-based Neurotransmitter Fluorescent Engineered Reporters CNiFERs for Optical Detection of Neurotransmitters In Vivo at JoVE.com

Construction of Cell-based Neurotransmitter Fluorescent Engineered Reporters CNiFERs for Optical Detection of Neurotransmitters In Vivo

We present a protocol to create cell-based neurotransmitter fluorescent engineered reporters (CNiFERs) for the optical detection of volumetric neurotransmitter release.

Construction of Cell-based Neurotransmitter Fluorescent Engineered Reporters (CNiFERs) for Optical Detection of Neurotransmitters In Vivo

Cell-based neurotransmitter fluorescent engineered reporters (CNiFERs) provide a new tool for neuroscientists to optically detect the release of ...

The overall goal of this video is to describe the methodology for the construction and testing of Cell-based Neurotransmitter Fluorescent Reporters, or CNiFERs, which can be used to optically monitor the release of specific neurotransmitters in vivo. This method can help answer key questions in neuroscience concerning the timing and the release of neuromodulators in the brain. The main advantage of this technique is that it can be adapted for any type of neurotransmitter or neuromodulator, that signals through GPCS.Regional demonstration of this method is helpful. It is the in vivo injection, and subsequent imaging of CNiFERs are technically challenging. To begin this procedure, see the HEK293 cells which contain the front based calcium detector and chimeric g protein in a T-25 flask.Then, grow the cells in a humidified incubator, at 37 degrees Celsius, with five percent CO2, until about 50%confluent. Afterward, aspirate the media from the T-25 flask. Add two milliliters of the lenta virus media mixture, and incubate the T-25 flask at 37 degrees Celsius, with 5%CO2.The next day, harvest the infected HEK293 cells by adding one milliliter of trypsin. Next, resuspend the cell pellet in five milliliters of HEK293 growth media. Seed one milliliter of cells in a T-75 flask for freezing and storage, and 1.5 milliliters of cells in a T-25 flask for FACS analysis.For the 10 point agonist curve, to test the infected cells, seed the first two rows of a fibronectin coated 96 well plate with 100 microliters of the cell suspension per well. Then, incubate the HEK293 cells growing in a T-25 flask, a T-75 flask, and a 96 well plate until about 90%confluent at 37 degrees Celsius with 5%CO2 for one to two days. Before FACS analysis, determine the functional expression of the GPCR by preparing a drug plate with 10 different agonist concentrations that bracket the predicted EC 50.Prepare different concentrations of agonist using a serial dilution method, and create a template, to keep track of the drug concentrations. Next, set the plate reader temperature to 37 degrees Celsius. Then, program the 96 well fluorometric plate reader for measuring fret, and performing solution transfers.For measuring fret with a genetically encoded fret based Calcium sensor, TNXXL, set the excitation wavelength at 436 plus or minus 4.5 nanometers. Then, set the emission filters, and the cut off filters, for ECFP and citrine. Next, program the plate reader to measure the emissions every four seconds, for a total of 180 seconds.Choose the options for 100 microleader plate volume, 150 microliter pipette height, and delivery of 50 micro liters of drug from the threefold compound plate. Set the time point for drug delivery at 30 seconds. After that, aspirate the media from rows A and B, and add 100 microliters of ACSF to the 96 well sniffer plate, that is about 90%confluent.Then, load the threefold drug plate and 96 well sniffer plate into the plate reader. Allow 30 minutes to equilibrate the plates at 37 degrees Celsius, before starting the program. After the plate reader run, export the fluorescence reader values to a text file.Then, import this file to a previously made spreadsheet template that normalizes the florescence intensities to the pre-stimulus base lines, calculates the peak fret ratio for each agonist concentration, and generates a dose response curve. Prepare the CNiFER injection pipette by putting a glass capillary on a vertical electrode puller. Use a pair of forceps to break the tip of the electrode to a diameter of approximately 40 micrometers.Place an ACSF soaked sponge on a previously formed two by three millimeter thin skull window of an anesthetized mouse, to keep moist while preparing the cells for injection. Next, harvest the CNiFER clone that was grown in a T-75 flask to about 80%confluency. Aspirate the media, and wash the cells with sterile PBS.Remove PBS, and use 10 milliliters of ACFS to dislodge the cells from the bottom of the flask. Then, tritcherate the cells to dissociate the cell clumps. Centrifuge for two minutes in a cell culture centrifuge.Remove the supernatant, and resuspend the pellet in 100 microliters of ACSF. Subsequently, centrifuge for 30 seconds at 1400 times G, and remove the supernatant, leaving a pellet, covered in ACSF. Afterward, back fill the injection pipette with mineral oil.Load the pipette onto a nano injector. Put five microliters of CNiFER cell suspension onto a strip of plastic paraffin film near the mouse preparation. Draw up the CNiFER cells into the pulled pipette.Now, move the pipette to the target x and y coordinates. Lower the pipettes, and pierce the thinned skull, prepared previously. Continue to about 200 to 400 micrometers below the skull's surface, in layers two and three of the cortex.Inject 4.6 nanoliters of CNiFER cells at the deepest site with the nano injector. Note movement in the oil and cell interface. And then, wait for five minutes for the cells to dispense.Withdraw the pipette approximately 100 micrometers and inject another 4.6 nanoliters of CNiFER cells and again, wait five minutes. Afterward, withdraw the pipette slowly and gently to prevent backflow of the CNiFERs. In this procedure, place the imaging platform with the head restrained mouse under a 10x water immersion objective in a two photon imaging microscope.Insert the filter cube for fret imaging that has a dichroic mirror at 505 nanometers and band pass filters that span 460 nanometers to 500 nanometers for measuring ECFP and 520 nanometers to 560 nanometers for measuring citrine. Then, add ACSF to the well, containing the thinned skull window and lower the 10x water immersion objective into the ACSF. Use the eye piece in conjunction with mercury lamp, and GFP filter cube to locate the CNiFERs.Now, switch to the 40x water immersion objective. Next, select the appropriate light path for two photon imaging. Turn on the near infrared femtosecond pulse laser.Select the wavelength of 820 nanometers, and a power setting of five to 15%Set the pmt one and pmt two voltage to a submaximal value, typically 500-1000 volts, depending on the pmt. Then, set the gain to one for each channel, and zero the z position for the objective. Lower the objective approximately 100 to 200 micrometers from the cortical surface, and start the xy scan.Adjust the laser power, gain, and pmt voltage for each channel to optimize the signal to noise ratio of the CNiFER's florescence. Next, use the software to restrict the imaging to a region that contains the CNiFER cells, as well as a background region. Select the cowman line, averaging for two, for a suitable signal to noise ratio, and use a scan rate of 3 to one hertz at four microseconds per pixel.After that, draw an ROI around the CNiFER cells. Surrounding about three to four cells per plane. Set up real time analysis of ROI average intensities.Then, start acquisition to monitor the CNiFER florescence over time and begin electrical stimulation or behavioral experiment, while monitoring fret. In this example, D2R CNiFER fret's response was measured on a plate reader with a solution delivery system. This graph shows the fret response during the application of dopamine to D2 CNiFERs.Note that ECFP emission decreases while citrine emission increases with dopamine. And here is a plot of the corresponding fret ratio. Shown here are the dose response curves for the response of D2 CNiFERs to dopamine and to norepinepherine.In addition, the responsive control CNiFERs lacking the D2R is presented. This bar graph shows the fret ratio response for other neurotransmitters and modulators at 50 nano molar and one micro molar. Here, electrical stimulation of DA neurons in the substantia nigra, elicits a large change in the fret ratio for D2 CNiFERs.Note how the amplitude of the response increases with an increasing intensity of electrical stimulation. Coupling stimulation with cocaine injection augments the CNiFER response. After watching this video, you should have a good understanding of how to create, test, and use CNiFERs for in vivo imaging.Throughout the development of CNiFERs, it is essential to maintain sterile technique, because these cells will be ultimately implanted in living mice. The realization of CNiFERs provides an important tool for researches in the field of neuroscience to optically measure the release of any neurotransmitter, or neuromodulator, that signals through a G protein coupled receptor. Thank you for watching, and good luck with your experiments.

construction-cell-based-neurotransmitter-fluorescent-engineered

Research

JoVE Journal

Neuroscience

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from individual neurons are critical for understanding how neural circuits function under natural conditions. Traditionally, these recordings have been performed 'blind', meaning the identity of the recorded cell is unknown at the start of the recording. Cellular identity can be subsequently determined via intracellular1, juxtacellular2 or loose-patch3 iontophoresis of dye, but these recordings cannot be pre-targeted to specific neurons in regions with functionally heterogeneous cell types. Fluorescent proteins can be expressed in a cell-type specific manner permitting visually-guided single-cell electrophysiology4-6. However, there are many model systems for which these genetic tools are not available. Even in genetically accessible model systems, the desired promoter may be unknown or genetically homogenous neurons may have varying projection patterns. Similarly, viral vectors have been used to label specific subgroups of projection neurons7, but use of this method is limited by toxicity and lack of trans-synaptic specificity. Thus, additional techniques that offer specific pre-visualization to record from identified single neurons in vivo are needed. Pre-visualization of the target neuron is particularly useful for challenging recording conditions, for which classical single-cell recordings are often prohibitively difficult8-11. The novel technique described in this paper uses retrograde transport of a fluorescent dye applied using tungsten needles to rapidly and selectively label a specific subset of cells within a particular brain region based on their unique axonal projections, thereby providing a visual cue to obtain targeted electrophysiological recordings from identified neurons in an intact circuit within a vertebrate CNS.
The most significant novel advancement of our method is the use of fluorescent labeling to target specific cell types in a non-genetically accessible model system. Weakly electric fish are an excellent model system for studying neural circuits in awake, behaving animals12. We utilized this technique to study sensory processing by "small cells" in the anterior exterolateral nucleus (ELa) of weakly electric mormyrid fish. "Small cells" are hypothesized to be time comparator neurons important for detecting submillisecond differences in the arrival times of presynaptic spikes13. However, anatomical features such as dense myelin, engulfing synapses, and small cell bodies have made it extremely difficult to record from these cells using traditional methods11, 14. Here we demonstrate that our novel method selectively labels these cells in 28% of preparations, allowing for reliable, robust recordings and characterization of responses to electrosensory stimulation.

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

Retrograde transport of fluorescent dye labels a sub-population of neurons based on anatomical projection. Labeled axons can be visually targeted in vivo, permitting extracellular recording from identified axons. This technique facilitates recording when neurons cannot be labeled through genetic manipulation or are difficult to isolate using 'blind' in vivo approaches.

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from ...

Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains technically challenging. One approach, Activation-Induced Manganese-enhanced MRI (AIM MRI), has been used successfully to map neuronal activity in rodents 1-5. In AIM MRI, Mn2+ acts a calcium analog and accumulates in depolarized neurons 6,7. Because Mn2+ shortens the T1 tissue property, regions of elevated neuronal activity will enhance in MRI. Furthermore, Mn2+ clears slowly from the activated regions; therefore, stimulation can be performed outside the magnet prior to imaging, enabling greater experimental flexibility. However, because Mn2+ does not readily cross the blood-brain barrier (BBB), the need to open the BBB has limited the use of AIM MRI, especially in mice.
One tool for opening the BBB is ultrasound. Though potentially damaging, if ultrasound is administered in combination with gas-filled microbubbles (i.e., ultrasound contrast agents), the acoustic pressure required for BBB opening is considerably lower. This combination of ultrasound and microbubbles can be used to reliably open the BBB without causing tissue damage 8-11.
Here, a method is presented for performing AIM MRI by using microbubbles and ultrasound to open the BBB. After an intravenous injection of perflutren microbubbles, an unfocused pulsed ultrasound beam is applied to the shaved mouse head for 3 minutes. For simplicity, we refer to this technique of BBB Opening with Microbubbles and UltraSound as BOMUS 12. Using BOMUS to open the BBB throughout both cerebral hemispheres, manganese is administered to the whole mouse brain. After experimental stimulation of the lightly sedated mice, AIM MRI is used to map the neuronal response.
To demonstrate this approach, herein BOMUS and AIM MRI are used to map unilateral mechanical stimulation of the vibrissae in lightly sedated mice 13. Because BOMUS can open the BBB throughout both hemispheres, the unstimulated side of the brain is used to control for nonspecific background stimulation. The resultant 3D activation map agrees well with published representations of the vibrissae regions of the barrel field cortex 14. The ultrasonic opening of the BBB is fast, noninvasive, and reversible; and thus this approach is suitable for high-throughput and/or longitudinal studies in awake mice.

A technique is described for broadly opening the blood-brain barrier in the mouse using microbubbles and ultrasound. Using this technique, manganese can be administered to the mouse brain. Because manganese is an MRI contrast agent that accumulates in depolarized neurons, this approach enables imaging of neuronal activity.

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains ...

Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging

Optical coherence tomography (OCT) is a biomedical imaging technique with high spatial-temporal resolution. With its minimally invasive approach OCT has been used extensively in ophthalmology, dermatology, and gastroenterology1-3. Using a thinned-skull cortical window (TSCW), we employ spectral-domain OCT (SD-OCT) modality as a tool to image the cortex in vivo. Commonly, an opened-skull has been used for neuro-imaging as it provides more versatility, however, a TSCW approach is less invasive and is an effective mean for long term imaging in neuropathology studies. Here, we present a method of creating a TSCW in a mouse model for in vivo OCT imaging of the cerebral cortex.

Thinned-skull Cortical Window Technique for In Vivo Optical Coherence Tomography Imaging

We present a method of creating a thinned-skull cortical window (TSCW) in a mouse model for in vivo OCT imaging of the cerebral cortex.

Optical coherence tomography (OCT) is a biomedical imaging technique  with high spatial-temporal resolution. With its minimally invasive approach OCT  has ...

Detection of the Genome and Transcripts of a Persistent DNA Virus in Neuronal Tissues by Fluorescent In situ Hybridization Combined with Immunostaining

Single cell codetection of a gene, its RNA product and cellular regulatory proteins is critical to study gene expression regulation. This is a challenge in the field of virology; in particular for nuclear-replicating persistent DNA viruses that involve animal models for their study. Herpes simplex virus type 1 (HSV-1) establishes a life-long latent infection in peripheral neurons. Latent virus serves as reservoir, from which it reactivates and induces a new herpetic episode. The cell biology of HSV-1 latency remains poorly understood, in part due to the lack of methods to detect HSV-1 genomes in situ in animal models. We describe a DNA-fluorescent in situ hybridization (FISH) approach efficiently detecting low-copy viral genomes within sections of neuronal tissues from infected animal models. The method relies on heat-based antigen unmasking, and directly labeled home-made DNA probes, or commercially available probes. We developed a triple staining approach, combining DNA-FISH with RNA-FISH&#160;and immunofluorescence, using peroxidase based signal amplification to accommodate each staining requirement. A major improvement is the ability to obtain, within 10 &#181;m tissue sections, low-background signals that can be imaged at high resolution by confocal microscopy and wide-field conventional epifluorescence. Additionally, the triple staining worked with a wide range of antibodies directed against cellular and viral proteins. The complete protocol takes 2.5 days to accommodate antibody and probe penetration within the tissue.

Detection of the Genome and Transcripts of a Persistent DNA Virus in Neuronal Tissues by Fluorescent In situ Hybridization Combined with Immunostaining

We established a fluorescent in situ hybridization protocol for the detection of a persistent DNA virus genome within tissue sections of animal models. This protocol enables studying infection process by codetection of the viral genome, its RNA products, and viral or cellular proteins within single cells.

Single cell codetection of a gene, its RNA product and cellular regulatory proteins is critical to study gene expression regulation. This is a challenge ...

Modeling Astrocytoma Pathogenesis In Vitro and In Vivo Using Cortical Astrocytes or Neural Stem Cells from Conditional, Genetically Engineered Mice

Current astrocytoma models are limited in their ability to define the roles of oncogenic mutations in specific brain cell types during disease pathogenesis and their utility for preclinical drug development. In order to design a better model system for these applications, phenotypically wild-type cortical astrocytes and neural stem cells (NSC) from conditional, genetically engineered mice (GEM) that harbor various combinations of floxed oncogenic alleles were harvested and grown in culture. Genetic recombination was induced in vitro using adenoviral Cre-mediated recombination, resulting in expression of mutated oncogenes and deletion of tumor suppressor genes. The phenotypic consequences of these mutations were defined by measuring proliferation, transformation, and drug response in vitro. Orthotopic allograft models, whereby transformed cells are stereotactically injected into the brains of immune-competent, syngeneic littermates, were developed to define the role of oncogenic mutations and cell type on tumorigenesis in vivo. Unlike most established human glioblastoma cell line xenografts, injection of transformed GEM-derived cortical astrocytes into the brains of immune-competent littermates produced astrocytomas, including the most aggressive subtype, glioblastoma, that recapitulated the histopathological hallmarks of human astrocytomas, including diffuse invasion of normal brain parenchyma. Bioluminescence imaging of orthotopic allografts from transformed astrocytes engineered to express luciferase was utilized to monitor in vivo tumor growth over time. Thus, astrocytoma models using astrocytes and NSC harvested from GEM with conditional oncogenic alleles provide an integrated system to study the genetics and cell biology of astrocytoma pathogenesis in vitro and in vivo and may be useful in preclinical drug development for these devastating diseases.

Modeling Astrocytoma Pathogenesis In Vitro and In Vivo Using Cortical Astrocytes or Neural Stem Cells from Conditional, Genetically Engineered Mice

Phenotypically wild-type astrocytes and neural stem cells harvested from mice engineered with floxed, conditional oncogenic alleles and transformed via viral Cre-mediated recombination can be used to model astrocytoma pathogenesis in vitro and in vivo by orthotopic injection of transformed cells into brains of syngeneic, immune-competent littermates.

Current astrocytoma models are limited in their ability to define the roles of oncogenic mutations in specific brain cell types during disease ...

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise from extra-retinal sources. Ex vivo ERG provides an efficient method to dissect the function of retinal cells directly from an intact isolated retina of animals or donor eyes. In addition, ex vivo ERG can be used to test the efficacy and safety of potential therapeutic agents on retina tissue from animals or humans. We show here how commercially available in vivo ERG systems can be used to conduct ex vivo ERG recordings from isolated mouse retinas. We combine the light stimulation, electronic and heating units of a standard in vivo system with custom-designed specimen holder, gravity-controlled perfusion system and electromagnetic noise shielding to record low-noise ex vivo ERG signals simultaneously from two retinas with the acquisition software included in commercial in vivo systems. Further, we demonstrate how to use this method in combination with pharmacological treatments that remove specific ERG components in order to dissect the function of certain retinal cell types.

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

Ex vivo ERG can be used to record electrical activity of retinal cells directly from isolated intact retinas of animals or humans. We demonstrate here how common in vivo ERG systems can be adapted for ex vivo ERG recordings in order to dissect the electrical activity of retinal cells.

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise ...

Optical Monitoring of Living Nerve Terminal Labeling in Hair Follicle Lanceolate Endings of the Ex Vivo Mouse Ear Skin

A novel dissection and recording technique is described for optical monitoring staining and de-staining of lanceolate terminals surrounding hair follicles in the skin of the mouse pinna. The preparation is simple and relatively fast, reliably yielding extensive regions of multiple labeled units of living nerve terminals to study uptake and release of styryl pyridinium dyes extensively used in studies of vesicle recycling. Subdividing the preparations before labeling allows test vs. control comparisons in the same ear from a single individual. Helpful tips are given for improving the quality of the preparation, the labeling and the imaging parameters. This new system is suitable for assaying pharmacologically and mechanically-induced uptake and release of these vital dyes in lanceolate terminals in both wild-type and genetically modified animals. Examples of modulatory influences on labeling intensity are given.

Optical Monitoring of Living Nerve Terminal Labeling in Hair Follicle Lanceolate Endings of the Ex Vivo Mouse Ear Skin

Here we describe a novel preparation for imaging live lanceolate sensory terminals of palisade endings that innervate mouse ear skin hair follicles during staining and destaining with styryl pyridinium dyes.

A novel dissection and recording technique is described for optical monitoring staining and de-staining of lanceolate terminals surrounding hair follicles ...

Optical Coherence Tomography: Imaging Mouse Retinal Ganglion Cells In Vivo

Structural changes in the retina are common manifestations of ophthalmic diseases. Optical coherence tomography (OCT) enables their identification in vivo&#8212;rapidly, repetitively, and at a high resolution. This protocol describes OCT imaging in the mouse retina as a powerful tool to study optic neuropathies (OPN). The OCT system is an interferometry-based, non-invasive alternative to common post mortem histological assays. It provides a fast and accurate assessment of retinal thickness, allowing the possibility to track changes, such as retinal thinning or thickening. We present the imaging process and analysis with the example of the Opa1delTTAG mouse line. Three types of scans are proposed, with two quantification methods: standard and homemade calipers. The latter is best for use on the peripapillary retina during radial scans; being more precise, is preferable for analyzing thinner structures. All approaches described here are designed for retinal ganglion cells (RGC) but are easily adaptable to other cell populations. In conclusion, OCT is efficient in mouse model phenotyping and has the potential to be used for the reliable evaluation of therapeutic interventions.

Optical Coherence Tomography: Imaging Mouse Retinal Ganglion Cells In Vivo

This manuscript describes a protocol for the in vivo imaging of the mouse retina with high-resolution spectral domain optical coherence tomography (SD-OCT). It focuses on retinal ganglion cells (RGC) in the peripapillary region, with several scanning and quantifying approaches described.

Structural changes in the retina are common manifestations of ophthalmic diseases. Optical coherence tomography (OCT) enables their identification in ...

Measuring In Vivo Changes in Extracellular Neurotransmitters During Naturally Rewarding Behaviors in Female Syrian Hamsters

The ability to measure neurotransmitter release on a rapid time scale allows patterns of neurotransmission to be linked to specific behaviors or manipulations; a powerful tool in elucidating underlying mechanisms and circuitry. While the technique of microdialysis has been used for decades to measure nearly any analyte of interest in the brain, this technique is limited in temporal resolution. Alternatively, fast scan cyclic voltammetry is both temporally precise and extremely sensitive; however, because this technically difficult method relies on the electroactivity of the analyte of interest, the possibility to detect nonelectroactive substances (e.g., the neurotransmitter glutamate) is eliminated. This paper details the use of a turn-key system that combines fixed-potential amperometry and enzymatic biosensing to measure both electroactive and nonelectroactive neurotransmitters with temporal precision. The pairing of these two powerful techniques allows for the measurement of both tonic and phasic neurotransmission with relative ease, and permits recording of multiple neurotransmitters simultaneously. The aim of this manuscript is to demonstrate the process of measuring dopamine and glutamate neurotransmission in vivo using a naturally rewarding behavior (i.e., sexual behavior) in female hamsters, with the ultimate goal of displaying the technical feasibility of this assay for examining other behaviors and experimental paradigms.

Measuring In Vivo Changes in Extracellular Neurotransmitters During Naturally Rewarding Behaviors in Female Syrian Hamsters

This paper details the use of fixed-potential amperometric recordings using carbon fiber electrodes and enzymatic biosensor technology to measure the release of dopamine and glutamate with high temporal resolution during natural rewarding behavior in the female hamster.

The ability to measure neurotransmitter release on a rapid time scale allows patterns of neurotransmission to be linked to specific behaviors or ...

In Vivo Monitoring of Circadian Clock Gene Expression in the Mouse Suprachiasmatic Nucleus Using Fluorescence Reporters

This technique combines optical fiber mediated fluorescence recordings with the precise delivery of recombinant adeno-associated virus based gene reporters. This new and easy to use in vivo fluorescence monitoring system was developed to record the transcriptional rhythm of the clock gene, Cry1, in the suprachiasmatic nucleus (SCN) of freely moving mice. To do so, a Cry1 transcription fluorescence reporter was designed and packaged into Adeno-associated virus. Purified, concentrated virus was injected into the mouse SCN followed by the insertion of an optic fiber, which was then fixed onto the surface of the brain. The animals were returned to their home cages and allowed a 1-month post-operative recovery period to ensure sufficient reporter expression. Fluorescence was then recorded in freely moving mice via an in vivo monitoring system that was constructed at our institution. For the in vivo recording system, a 488 nm laser was coupled with a 1 &#215; 4 beam-splitter that divided the light into four laser excitation outputs of equal power. This setup enabled us to record from four animals simultaneously. Each of the emitted fluorescence signals was collected via a photomultiplier tube and a data acquisition card. In contrast to the previous bioluminescence in vivo circadian clock recording technique, this fluorescence in vivo recording system allowed the recording of circadian clock gene expression during the light cycle.

In Vivo Monitoring of Circadian Clock Gene Expression in the Mouse Suprachiasmatic Nucleus Using Fluorescence Reporters

This newly developed fluorescence-based technology enables long-term monitoring of the transcription of circadian clock genes in the suprachiasmatic nucleus (SCN) of freely moving mice in real-time and at a high temporal resolution.