Name: hsv-mediated transgene expression of chimeric constructs to study behavioral function of gpcr heteromers in mice
Uploaded: 2016-07-09T13:00:00
Description: Watch this Scientific Journal Video about HSV-Mediated Transgene Expression of Chimeric Constructs to Study Behavioral Function of GPCR Heteromers in Mice at JoVE.com

NIH R01MH084894 participated in the funding of this study. We would like to thank Drs. Yasmin Hurd and Scott Russo at Mount Sinai School of Medicine for the donation of mice and the use of their surgery and behavior facilities during the filming of this work.

NOTE: All procedures for animal breeding and cares were conducted according to the Institutional Animal Care and Use Committee&#160;(IACUC) regulation of Icahn School of Medicine at Mount Sinai. Be sure to use sterile gloves throughout the procedure.&#160;
1. Drug and Virus Preparation
<ol>
	<li>Drug Preparation
	<ol>
		<li>Prepare 15.0 ml ketamine/xylazine anesthetic by dissolving 1.35 ml of 100 mg/ml Ketamine and 0.75 ml of 20 mg/ml xylazine in 12.9 ml of 0.9% Saline solution. Thoroughly mix s...

<ol>
	<li>Fribourg, M., 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=Decoding+the+Signaling+of+a+GPCR+Heteromeric+Complex+Reveals+a+Unifying+Mechanism+of+Action+of+Antipsychotic+Drugs.">Decoding the Signaling of a GPCR Heteromeric Complex Reveals a Unifying Mechanism of Action of Antipsychotic Drugs.</a> Cell. 147 (5), 1011-1023 (2011).</li><li>Gonzalez-Maeso, 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=Identification+of+a+serotonin/glutamate+receptor+complex+implicated+in+psychosis.">Identification of a serotonin/glutamate receptor complex implicated in psychosis.</a> Nature. 452 (7183), 93-97 (2008).</li><li>Gonzalez-Maeso, 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=Hallucinogens+Recruit+Specific+Cortical+5-HT(2A)+Receptor-Mediated+Signaling+Pathways+to+Affect+Behavior.">Hallucinogens Recruit Specific Cortical 5-HT(2A) Receptor-Mediated Signaling Pathways to Affect Behavior.</a> Neuron. 53 (3), 439-452 (2007).</li><li>Gonzalez-Maeso, 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=Transcriptome+fingerprints+distinguish+hallucinogenic+and+nonhallucinogenic+5-hydroxytryptamine+2A+receptor+agonist+effects+in+mouse+somatosensory+cortex.">Transcriptome fingerprints distinguish hallucinogenic and nonhallucinogenic 5-hydroxytryptamine 2A receptor agonist effects in mouse somatosensory cortex.</a> J Neurosci. 23 (26), 8836-8843 (2003).</li><li>Moreno, J. L., Holloway, T., Albizu, L., Sealfon, S. C., Gonzalez-Maeso, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabotropic+glutamate+mGlu2+receptor+is+necessary+for+the+pharmacological+and+behavioral+effects+induced+by+hallucinogenic+5-HT2A+receptor+agonists.">Metabotropic glutamate mGlu2 receptor is necessary for the pharmacological and behavioral effects induced by hallucinogenic 5-HT2A receptor agonists.</a> Neurosci Lett. 493 (3), 76-79 (2011).</li><li>Moreno, J. L., 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=Identification+of+Three+Residues+Essential+for+5-HT2A-mGlu2+Receptor+Heteromerization+and+its+Psychoactive+Behavioral+Function.">Identification of Three Residues Essential for 5-HT2A-mGlu2 Receptor Heteromerization and its Psychoactive Behavioral Function.</a> J Biol Chem. 287, 44301-44319 (2012).</li><li>Geyer, M. A., Vollenweider, F. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serotonin+research:+contributions+to+understanding+psychoses.">Serotonin research: contributions to understanding psychoses.</a> Trends Pharmacol Sci. 29 (9), 445-453 (2008).</li><li>Nichols, D. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hallucinogens.">Hallucinogens.</a> Pharmacol Ther. 101 (2), 131-181 (2004).</li><li>Hanks, J. B., Gonzalez-Maeso, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+serotonergic+psychedelics.">Animal models of serotonergic psychedelics.</a> ACS Chem Neurosci. 4 (1), 33-42 (2013).</li><li>Fiorella, D., Rabin, R. A., Winter, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+5-HT2A+and+5-HT2C+receptors+in+the+stimulus+effects+of+hallucinogenic+drugs.+II:+Reassessment+of+LSD+false+positives.">Role of 5-HT2A and 5-HT2C receptors in the stimulus effects of hallucinogenic drugs. II: Reassessment of LSD false positives.</a> Psychopharmacology (Berl). 121 (3), 357-363 (1995).</li><li>Vollenweider, F. X., Vollenweider-Scherpenhuyzen, M. F., Babler, A., Vogel, H., Hell, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Psilocybin+induces+schizophrenia-like+psychosis+in+humans+via+a+serotonin-2+agonist+action.">Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action.</a> Neuroreport. 9 (17), 3897-3902 (1998).</li><li>Moreno, J. L., Sealfon, S. C., Gonzalez-Maeso, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Group+II+metabotropic+glutamate+receptors+and+schizophrenia.">Group II metabotropic glutamate receptors and schizophrenia.</a> Cell Mol Life Sci. 66 (23), 3777-3785 (2009).</li><li>Kurita, M., 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=HDAC2+regulates+atypical+antipsychotic+responses+through+the+modulation+of+mGlu2+promoter+activity.">HDAC2 regulates atypical antipsychotic responses through the modulation of mGlu2 promoter activity.</a> Nat Neurosci. 15 (9), 1245-1254 (2012).</li><li>Kurita, M., 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=Repressive+Epigenetic+Changes+at+the+mGlu2+Promoter+in+Frontal+Cortex+of+5-HT2A+Knockout+Mice.">Repressive Epigenetic Changes at the mGlu2 Promoter in Frontal Cortex of 5-HT2A Knockout Mice.</a> Mol Pharmacol. 83 (6), 1166-1175 (2013).</li><li>Rives, M. L., 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=Crosstalk+between+GABAB+and+mGlu1a+receptors+reveals+new+insight+into+GPCR+signal+integration.">Crosstalk between GABAB and mGlu1a receptors reveals new insight into GPCR signal integration.</a> Embo J. 28 (15), 2195-2208 (2009).</li><li>Milligan, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Prevalence,+Maintenance+and+Relevance+of+GPCR+Oligomerization.">The Prevalence, Maintenance and Relevance of GPCR Oligomerization.</a> Mol Pharmacol. (84), 158-169 (2013).</li><li>Ferre, 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=G+protein-coupled+receptor+oligomerization+revisited:+functional+and+pharmacological+perspectives.">G protein-coupled receptor oligomerization revisited: functional and pharmacological perspectives.</a> Pharmacol Rev. 66 (2), 413-434 (2014).</li><li>Gonzalez-Maeso, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GPCR+oligomers+in+pharmacology+and+signaling.">GPCR oligomers in pharmacology and signaling.</a> Mol Brain. 4 (1), 20 (2011).</li><li>Gonzalez-Maeso, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Family+a+GPCR+heteromers+in+animal+models.">Family a GPCR heteromers in animal models.</a> Front Pharmacol. 5, 226 (2014).</li><li>Dragulescu-Andrasi, A., Chan, C. T., De, A., Massoud, T. F., Gambhir, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioluminescence+resonance+energy+transfer+(BRET)+imaging+of+protein-protein+interactions+within+deep+tissues+of+living+subjects.">Bioluminescence resonance energy transfer (BRET) imaging of protein-protein interactions within deep tissues of living subjects.</a> Proceedings of the National Academy of Sciences of the United States of America. 108 (29), 12060-12065 (2011).</li><li>Calebiro, D., 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=Single-molecule+analysis+of+fluorescently+labeled+G-protein-coupled+receptors+reveals+complexes+with+distinct+dynamics+and+organization.">Single-molecule analysis of fluorescently labeled G-protein-coupled receptors reveals complexes with distinct dynamics and organization.</a> Proc Natl Acad Sci U S A. 110 (2), 743-748 (2013).</li><li>Fonseca, J. M., Lambert, N. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Instability+of+a+class+a+G+protein-coupled+receptor+oligomer+interface.">Instability of a class a G protein-coupled receptor oligomer interface.</a> Mol Pharmacol. 75 (6), 1296-1299 (2009).</li><li>Hern, J. A., 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=Formation+and+dissociation+of+M1+muscarinic+receptor+dimers+seen+by+total+internal+reflection+fluorescence+imaging+of+single+molecules.">Formation and dissociation of M1 muscarinic receptor dimers seen by total internal reflection fluorescence imaging of single molecules.</a> Proc Natl Acad Sci U S A. 107 (6), 2693-2698 (2010).</li><li>Hlavackova, V., 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=Sequential+inter-+and+intrasubunit+rearrangements+during+activation+of+dimeric+metabotropic+glutamate+receptor+1.">Sequential inter- and intrasubunit rearrangements during activation of dimeric metabotropic glutamate receptor 1.</a> Sci Signal. 5 (237), 59 (2012).</li><li>Irannejad, R., 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=Conformational+biosensors+reveal+GPCR+signalling+from+endosomes.">Conformational biosensors reveal GPCR signalling from endosomes.</a> Nature. 495 (7442), 534-538 (2013).</li><li>Calebiro, D., Nikolaev, V. O., Persani, L., Lohse, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Signaling+by+internalized+G-protein-coupled+receptors.">Signaling by internalized G-protein-coupled receptors.</a> Trends Pharmacol Sci. 31 (5), 221-228 (2010).</li><li>Celada, P., Puig, M. V., Diaz-Mataix, L., Artigas, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+hallucinogen+DOI+reduces+low-frequency+oscillations+in+rat+prefrontal+cortex:+reversal+by+antipsychotic+drugs.">The hallucinogen DOI reduces low-frequency oscillations in rat prefrontal cortex: reversal by antipsychotic drugs.</a> Biol Psychiatry. 64 (5), 392-400 (2008).</li><li>B&#233;&#239;que, J. -. C., Imad, M., Mladenovic, L., Gingrich, J. A., Andrade, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+of+the+5-hydroxytryptamine+2A+receptor-mediated+facilitation+of+synaptic+activity+in+prefrontal+cortex.">Mechanism of the 5-hydroxytryptamine 2A receptor-mediated facilitation of synaptic activity in prefrontal cortex.</a> Proceedings of the National Academy of Sciences of the United States of America. 104 (23), 9870-9875 (2007).</li></ol>

Together with previous findings in mGlu2-KO mice5, the results with mGlu2 and mGlu2/mGlu3 chimeric constructs that do not form the 5-HT2A-mGlu2 receptor complex in cultured cells suggest that the 5-HT2A -mGlu2 heteromeric receptor complex in mouse frontal cortex is needed to induce head-twitch behavior by LSD-like hallucinogenic 5-HT2A receptor agonists. A limitation of this method is that it does not measure close molecular proximity at a subcellular level in native tissue. In...

Hallucinogens, such as LSD, psilocybin and mescaline cause significant changes in human consciousness, cognition and emotion7-9. Inactivation of serotonin 5-HT2A receptor signaling by either genetic or pharmacological approaches causes markedly attenuated behavioral responses to hallucinogens in both rodent models3,10 and humans11. Although hallucinogens bind other receptor subtypes8, the 5-HT2A receptor is considered as necessary for the unique behavioral activity of these chemicals.
Group II metabotropic glutamate receptors (i.e., mGlu2 and mGlu3) have been the target of considerable attention regarding the molecular mechanism of hallucinogens and their integral role underlying psychosis12. Previously, it has been demonstrated that mice with no expression of mGlu2 protein (mGlu2-KO mice) are insensitive to the cellular and behavioral effects of hallucinogens5. It has also been suggested that the 5-HT2A and the mGlu2 receptors form a specific heteromeric complex through which serotonin and glutamate ligands modulate the pattern of G protein coupling in living cells 1,2.
Structurally, transmembrane (TM) domains 4 and 5 of mGlu2 play a fundamental role in heteromeric formation with the 5-HT2A receptor5. Additionally, further investigation demonstrated that three residues located at the intracellular end of TM4 of mGlu2 are necessary to form the 5-HT2A-mGlu2 receptor heterocomplex in living cells6.
Based on these findings observed in heterologous expression systems, here we describe the use of HSV-mediated expression of wild-type mGlu2 and mGlu2/mGlu3 chimeric constructs in the frontal cortex of mGlu2-KO mice to test whether heteromeric formation between 5-HT2A and mGlu2 is necessary for the head-twitch behavior induced by hallucinogenic 5-HT2A receptor agonists.

<table border="0" cellpadding="0" cellspacing="0" width="2329">
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		<tr height="21">
			<td height="21" style="height:21px;width:423px;">mGlu2 bicitronic herpes simplex virus (HSV) vector&#160;</td>
			<td style="width:71px;">MIT Core</td>
			<td style="width:119px;"></td>
			<td style="width:1716px;">mGlu2 and mGlu2DTM4N were subcloned into the bicistronic HSV-GFP virus vector p1005+ HSV expressing GFP under the control of the CMV promoter. Viral particles were produced by the Viral Core Facility at the McGovern Institute (MIT). For more information, please contact the director, Dr. Rachael Neve (rneve@mit.edu)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">mGlu2&#916;TM4N bicitronic herpes simplex virus (HSV) vector&#160;</td>
			<td style="width:71px;">MIT Core</td>
			<td style="width:119px;"></td>
			<td>mGlu2 and mGlu2DTM4N were subcloned into the bicistronic HSV-GFP virus vector p1005+ HSV expressing GFP under the control of the CMV promoter. Viral particles were produced by the Viral Core Facility at the McGovern Institute (MIT). For more information, please contact the director, Dr. Rachael Neve (rneve@mit.edu)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GFP bicitronic herpes simplex virus (HSV) vector&#160;</td>
			<td style="width:71px;">MIT Core</td>
			<td style="width:119px;"></td>
			<td>mGlu2 and mGlu2DTM4N were subcloned into the bicistronic HSV-GFP virus vector p1005+ HSV expressing GFP under the control of the CMV promoter. Viral particles were produced by the Viral Core Facility at the McGovern Institute (MIT). For more information, please contact the director, Dr. Rachael Neve (rneve@mit.edu)</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:423px;">xylazine&#160;</td>
			<td style="width:71px;">Lloyd</td>
			<td style="width:119px;">List no. 4811-20ml, NADA #139-236, NDC Code(s): 61311-481-10</td>
			<td>1.35 mL of 100mg/ml of ketamine+.75 mL of 20mg/ml of xylazine are diluted in 12.0 mL of .9% saline solution</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;">ketamine&#160;</td>
			<td style="width:71px;">Vedco</td>
			<td style="width:119px;">KetaVed-10ml, NADA #200-029, NDC Code(s): 50989-161-06</td>
			<td>1.35 mL of 100mg/ml of ketamine+.75 mL of 20mg/ml of xylazine are diluted in 12.0 mL of .9% saline solution</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">ophthalmic gel</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td>NC0550805</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">burret clips</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td>NC9268369</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:423px;">Feather surgical blade</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td>NC9032736</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:423px;">Hydrogen Peroxide</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td>19-898-919&#160;</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Hamilton syringe</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td>14815203</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Hamilton&#8482; Small Hub Removable Needles (33 Ga)</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td>14816206</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Cordless Micro Drill</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td>NC9089241</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Dermabond Dermal Adhesive</td>
			<td style="width:71px;">Fisher Scientific</td>
			<td style="width:119px;">NC0690470</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">(&#177;)-1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI)</td>
			<td style="width:71px;">Sigma-Aldrich</td>
			<td>42203-78-1</td>
			<td>Dissolved in .9% saline solution to the concentration of 2.0 mg/kg</td>
		</tr>
	</tbody>
</table>

hsv-mediated transgene expression of chimeric constructs to study behavioral function of gpcr heteromers in mice

The heteromeric receptor complex between 5-HT2A and mGlu2 has been implicated in some of the behavioral phenotypes in mouse models of psychosis1,2. Consequently, investigation of structural details of the interaction between 5-HT2A and mGlu2 affecting schizophrenia-related behaviors represents a powerful translational tool. As previously shown, the head-twitch response (HTR) in mice is elicited by hallucinogenic drugs and this behavioral response is absent in 5-HT2A knockout (KO) mice3,4. Additionally, by conditionally expressing the 5-HT2A receptor only in cortex, it was demonstrated that 5-HT2A receptor-dependent signaling pathways on cortical pyramidal neurons are sufficient to elicit head-twitch behavior in response to hallucinogenic drugs3. Finally, it has been shown that the head-twitch behavioral response induced by the hallucinogens DOI and lysergic acid diethylamide (LSD) is significantly decreased in mGlu2-KO mice5. These findings suggest that mGlu2 is at least in part necessary for the 5-HT2A receptor-dependent psychosis-like behavioral effects induced by LSD-like drugs. However, this does not provide evidence as to whether the 5-HT2A-mGlu2 receptor complex is necessary for this behavioral phenotype. To address this question, herpes simplex virus (HSV) constructs to express either mGlu2 or mGlu2&#916;TM4N (mGlu2/mGlu3 chimeric construct that does not form the 5-HT2A-mGlu2 receptor complex) in the frontal cortex of mGlu2-KO mice were used to examine whether this GPCR heteromeric complex is needed for the behavioral effects induced by LSD-like drugs6.

Previous findings demonstrate that the head-twitch murine behavioral response is reliably and robustly elicited by hallucinogens, and it is absent in 5-HT2A-KO mice3. Furthermore, it has been shown that the head-twitch response elicited by the hallucinogenic 5-HT2A agonists DOI and LSD was significantly decreased in mGlu2-KO mice5. However, although previous findings convincingly demonstrate that 5-HT2A and mGlu2 are assembled as a he...

Watch this Scientific Journal Video about HSV-Mediated Transgene Expression of Chimeric Constructs to Study Behavioral Function of GPCR Heteromers in Mice at JoVE.com

HSV-Mediated Transgene Expression of Chimeric Constructs to Study Behavioral Function of GPCR Heteromers in Mice

This article describes how to inject viral vectors into the mouse frontal cortex to test behavioral assays that require GPCR heteromeric formation.

The heteromeric receptor complex between 5-HT2A and mGlu2 has been implicated in some of the behavioral phenotypes in mouse models of psychosis1,2.  ...

The overall goal of this method is to observe how virus-mediated gene transfer affects behavioral phenotypes that require heterodimerization of G-protein coupled receptors in mouse models. This method can help answer key questions in the field of neuro and psycho pharmacology. Specifically how g protein coupled receptors interact with each other at a molecular level.By using this method we can understand how this interaction affects behavior in models of psychiatric disorders, such as schizophrenia and depression. Using this method we are going to specifically look at seratonin 2a and metabotropic glutamate receptor 2, both of which have been shown to be implicated in the mechanism of action of drugs used to treat patients with schizophrenia. Begin by properly anesthetizing the mouse according to approved methods.Ensure that a surgical plane of anesthesia has been obtained by performing a toe pinch and noting the absence of a response. Then apply ophthalmic gel to protect the eyes. Attach the mouse to the stereotactic frame, making sure to adjust the tilt of the head so that the skull is level and flat.Apply povidone iodine to the exposed scalp. Using a scalpel make a sagittal incision along the midline of the skull within the exposed shaved area. Then attach pureit clamps to the skin at the incision site to make sure that the skull remains exposed.Apply hydrogen peroxide to dissolve away the periosteum, and expose the sutures of the skull. Now that the bregma and sutures are visible, be sure to adjust the stereotactic frame to make sure that the skull is level. Align the needle tips of the syringes with bregma and record the coordinates of bregma.To bilaterally inject the frontal cortex, add 1.6 mm to the recorded rostral caudal bregma coordinate, and 2.6 mm to the recorded medial lateral bregma coordinate. Mark the injection sites on the skull and then drill small holes at the injection sites. With a cotton tip applicator, wipe away any excess blood or bone fragments.Bring the needle to the surface of the brain, and lower to the depth of the dorsal ventral coordinate. Then slowly inject the contents of the syringe by twisting the plunger of the needle to administer 0.1 microliters per minute for five minutes, for a 0.5 microliter injection. Allow the syringe to remain in place for five minutes.After the allotted time, remove the animal from the stereotaxis, close the incision, and place on a warming pad. Administer post operative analgesia according to your approved animal protocol. Perform behavioral testing two to three days after stereotactic injection of viral particles.Habituate the mice to the room for at least four hours prior to the beginning of the experiment. Begin by dissolving DOI into a 0.9 percent saline solution to two milligrams per kilogram. Prepare a home cage without any bedding and using a tripod adjust a camera so that it is directly over the home cage.Calibrate the camera so that the entire home cage is in the field of view. Weigh the mouse and inject intraperitoneally with the appropriate dose of either 0.9 percent saline or DOI. Place the mouse back in the home cage for ten minutes.After ten minutes, place the mouse into the center of the empty home cage, and ensure that there are no blind spots in the field of view of the camera. Press record on the camcorder and leave the room. After 30 minutes, stop the recording and place the mouse back in the original home cage.Repeat the behavioral test on the next mouse. Have the referee review the videos blind to the experimental conditions. Manually record every head twitch throughout the video.A head twitch is defined as a rapid shaking head movement conducted by a mouse. Process the data as outlined in the written portion of the protocol. Shown here is a representative image of HSV mediated transgene expression in the frontal cortex.HSV mGlu2 GFP was injected into the frontal cortex and GFP expression was revealed by immunocytochemistry. This scale bar represents 200 microns. This image shows a western blot of HSV mediated transgene expression and anti-mGlu2 reactivity in the frontal cortex of mGlu2 knockout mice.Here we measured immunoreactivity of mGlu2 as a monomer. This histogram shows that viral mediated expression of mGlu2, but not of chimeric mGlu2 in the frontal cortex of mGlu2 knockout mice significantly rescues the head twitch response induced by the hallucinogenic seratonin 2a receptor agonist DOI. The most critical steps with this experiment are the timing between the viral injections, the head twitch response, and when the mice are sacrificed.Any delay can alter the results of the experiment or introduce ambiguity into the data. Once mastered, the mouse surgery will take approximately 30 minutes to inject the virus. The head twitch experiment should also take approximately 35 minutes per mouse.Staggering surgeries, or operating on more than one mouse at a time is recommended. This way one can maintain a timeline that allows the head twitch experiments to be done in the three to four days after surgery which is the peak expression time of the viral construct. Thanks for watching and good luck with your experiment.

Research

JoVE Journal

Neuroscience

A General Method for Evaluating Incubation of Sucrose Craving in Rats

For someone on a food-restricted diet, food craving in response to food-paired cues may serve as a key behavioral transition point between abstinence and ...

Local Application of Drugs to Study Nicotinic Acetylcholine Receptor Function in Mouse Brain Slices

Tobacco use leads to numerous health problems, including cancer, heart disease, emphysema, and stroke. Addiction to cigarette smoking is a prevalent ...

Juxtasomal Biocytin Labeling to Study the Structure-function Relationship of Individual Cortical Neurons

The cerebral cortex is characterized by multiple layers and many distinct cell-types that together as a network are responsible for many higher cognitive ...

A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

A Simple Behavioral Assay for Testing Visual Function in Xenopus laevis

Measurement of the visual function in the tadpoles of the frog, Xenopus laevis, allows screening for blindness in live animals. The optokinetic response ...

Assessment of Dendritic Arborization in the Dentate Gyrus of the Hippocampal Region in Mice

Dendritic arborization has been shown to be a reliable marker for examination of structural and functional integrity of neurons. Indeed, the complexity ...

Quantification of Filamentous Actin (F-actin) Puncta in Rat Cortical Neurons

Quantification of Filamentous Actin F-actin Puncta in Rat Cortical Neurons

Filamentous actin protein (F-actin) plays a major role in spinogenesis, synaptic plasticity, and synaptic stability. Changes in dendritic F-actin rich ...

A Free-breathing fMRI Method to Study Human Olfactory Function

The study of human olfaction is a highly complex and valuable field with applications ranging from biomedical research to clinical evaluation. Currently, ...

Adeno-associated Virus-mediated Transgene Expression in Genetically Defined Neurons of the Spinal Cord

Selective manipulation of spinal neuronal subpopulations has mainly been achieved by two different methods: 1) Intersectional genetics, whereby double or ...

The Power of Interstimulus Interval for the Assessment of Temporal Processing in Rodents

Temporal processing deficits have been implicated as a potential elemental dimension of higher-level cognitive processes, commonly observed in ...

Ballistic Labeling of Pyramidal Neurons in Brain Slices and in Primary Cell Culture

It has been reported that the size and shape of dendritic spines is related to their structural plasticity. To identify the morphological structure of ...