Name: drug-induced sensitization of adenylyl cyclase: assay streamlining and miniaturization for small molecule and sirna screening applications
Uploaded: 2014-01-27T14:00:00
Description: Watch this Scientific Journal Video about Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications at JoVE.com

The authors would like to acknowledge Mr. Richard Zink and Todd Wiernicki for methodological training and assay guidance. We also thank John Paul Spence for careful reading and editorial suggestions. This work was supported by the National Institute of Health MH 060397, Brain and Behavior Research Foundation, and Eli Lilly and Company through the Lilly Research Award Program (LRAP).

1. Expansion and Cryopreservation of Assay Ready Cells
<ol>
	<li>Culture CHO-K1-DRD2L (CHO-D2L) cells on a 15 cm2 cell culture dish in Ham&#39;s F12 media supplemented with 1.0 &#956;M L-glutamine, 800 &#956;g/&#956;l G418, 300 &#956;g/&#956;l hygromycin, 100 u/&#956;l penicillin, 100 &#956;g/&#956;l streptomycin, and 10% fetal bovine serum (FBS).</li>
	<li>Incubate the cells at 37 &#176;C in a humidified incubator with 5% CO2 until the cells are 90-95% confluent. Wash the ce...

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	<li>Sharma, S. K., Klee, W. A., Nirenberg, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual+regulation+of+adenylate+cyclase+accounts+for+narcotic+dependence+and+tolerance.">Dual regulation of adenylate cyclase accounts for narcotic dependence and tolerance.</a> Proc. Natl. Acad. Sci. U.S.A. 72, 3092-3096 (1975).</li><li>Watts, V. J., Neve, K. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitization+of+adenylate+cyclase+by+Galpha(i/o)-coupled+receptors.">Sensitization of adenylate cyclase by Galpha(i/o)-coupled receptors.</a> Pharmacol. Ther. 106, 405-421 (2005).</li><li>Christie, M. 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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=Adenylyl+cyclase+type+5+(AC5)+is+an+essential+mediator+of+morphine+action.">Adenylyl cyclase type 5 (AC5) is an essential mediator of morphine action.</a> Proc. Natl. Acad. Sci. U.S.A. 103, 3908-3913 (2006).</li><li>Watts, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adenylyl+cyclase+isoforms+as+novel+therapeutic+targets:+an+exciting+example+of+excitotoxicity+neuroprotection.">Adenylyl cyclase isoforms as novel therapeutic targets: an exciting example of excitotoxicity neuroprotection.</a> Mol. Interv. 7, 70-73 (2007).</li><li>Beazely, M. A., Watts, V. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sensitization+of+endogenous+and+recombinant+adenylate+cyclase+by+activation+of+D2+dopamine+receptors.">Sensitization of endogenous and recombinant adenylate cyclase by activation of D2 dopamine receptors.</a> Mol. Pharmacol. 50, 966-976 (1996).</li><li>Nevo, I., 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=Regulation+of+adenylyl+cyclase+isozymes+on+acute+and+chronic+activation+of+inhibitory+receptors.">Regulation of adenylyl cyclase isozymes on acute and chronic activation of inhibitory receptors.</a> Mol. 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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopamine+D2+receptor-induced+heterologous+sensitization+of+adenylyl+cyclase+requires+Gas:+Characterization+of+Gas-insensitive+mutants+of+adenylyl+cyclase+V.">Dopamine D2 receptor-induced heterologous sensitization of adenylyl cyclase requires Gas: Characterization of Gas-insensitive mutants of adenylyl cyclase V.</a> Mol. Pharmacol. 60, 1168-1172 (2001).</li><li>Ejendal, K. F., Dessauer, C. W., Hebert, T. E., Watts, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopamine+D(2)+Receptor-Mediated+Heterologous+Sensitization+of+AC5+Requires+Signalosome+Assembly.">Dopamine D(2) Receptor-Mediated Heterologous Sensitization of AC5 Requires Signalosome Assembly.</a> J. Signal Transduct. 2012, 210324 (2012).</li><li>Johnston, C. A., Beazely, M. A., Vancura, A. F., Wang, J. K. T., Watts, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterologous+sensitization+of+adenylate+cyclase+is+protein+kinase+A-dependent+in+Cath.a+differentiated+(CAD)-D2L+cells.">Heterologous sensitization of adenylate cyclase is protein kinase A-dependent in Cath.a differentiated (CAD)-D2L cells.</a> J. Neurochem. 82, 1087-1096 (2002).</li><li>Wang, H., 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+an+adenylyl+cyclase+inhibitor+for+treating+neuropathic+and+inflammatory+pain.">Identification of an adenylyl cyclase inhibitor for treating neuropathic and inflammatory pain.</a> Sci. Transl. Med. 3, 65ra3 (2011).</li><li>Nordstedt, C., Fredholm, B. 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In an effort to facilitate studies of heterologous sensitization, we have extensively modified our previous method achieving a streamlined "mix and read" format that is amendable to high-throughput screening and mechanism of action examination. The major modifications to our protocol can be summarized as follows: 1) the use of cryopreserved cells as "assay-ready" reagents; 2) the miniaturization of the assay into 384-well format; and 3) the utilization of the HTRF measurement of cAMP.
The adop...

An adaptive adenylyl cyclase (AC) signaling response known as heterologous- or super-sensitization was first discovered in the laboratory of Nobel Laureate, Dr. Marshall Nirenberg. Dr. Nirenberg proposed that the observed increased AC responsiveness following chronic &#948; opioid receptor activation was a mechanism involved in opiate tolerance and dependence1. In addition to chronic &#948; opioid receptor activation, this neuroadaptive response of AC signaling also occurs following persistent activation of several other G&#945;i/o-coupled receptors2. Notably, many of these receptors are associated with pain, neuropsychiatric and neurological disorders, and include &#956;/&#954; opioid, D2/4 dopamine, 5HT1A, and M2/4 muscarinic receptors2. In addition to Dr. Nirenberg&#39;s findings, a large body of evidence exists linking sensitization of AC signaling to chronic opioid receptor activation both in vitro and in vivo3-7. Sensitization of AC has also been associated with a variety of diseases involving D2-like dopamine receptors including schizophrenia and Parkinson&#39;s disease (for review see reference2). Despite the potential importance of sensitization, the precise mechanism(s) associated with persistent G&#945;i/o-coupled receptor activation that leads to increased AC responsiveness remains largely unknown.
These studies provide the rationale for examining the mechanisms for sensitization of adenylyl cyclase as an important neurobiological target. Likewise, the physiological relevance of AC signaling8 and the importance that the individual AC isoforms hold in this adaptive response should also be recognized2,9,10. In the context of our research, the general features associated with heterologous sensitization of the recombinant isoforms of AC parallel those characteristics described for studying the endogenous isoforms of AC. Specifically, previous research has found that the activation of G&#945;i/o proteins and subsequent release/rearrangement &#946;&#947; subunits are important requirements for receptor induced sensitization of all AC isoforms. Additionally, several studies suggest that signaling from protein kinases and G&#946;&#947; subunits are involved in sensitization2,11-13. Individual ACs also display unique and distinct sensitization patterns12. For instance, persistent exposure of D2 receptors to agonists is associated with sensitization of AC1 and AC8 to Ca2+/calmodulin stimulation14,15, whereas the closely related AC3 is not sensitized2. AC2, AC4, and AC7 are closely related, however, only PKC-stimulated AC2 activity is robustly sensitized after prolonged exposure of D2 receptors to agonists7,14,16,17. Additionally, AC5 and AC6 show a marked degree of heterologous sensitization to Gas- and forskolin-stimulated cAMP accumulation following activation of D2 receptors14,18-20, but appear to differ in their requirement for G&#946;&#947; subunit-AC interactions21. Although most studies of AC sensitization have used model cell lines (e.g. HEK293 cells expressing individual AC isoforms), it appears that these findings translate to native neuronal cell models4,22. More recently, the effects of AC isoform selective small molecule inhibitors identified in HEK293 cells expressing AC isoforms can also be translated to in vivo behavioral studies23.
The lack of an identified molecular mechanism for heterologous sensitization likely reflects the complexity of the adaptive response as well as the unique regulatory properties of the individual AC isoforms12. Unraveling such complexity is further complicated by the use of cumbersome methodology that has limited academic investigators from employing unbiased approaches. For example, our previous mechanistic studies involved the use of continuously cultured cellular models using 24- and 48-well tissue culture format15. Cultured cells were typically grown for 48 hr and then subjected to agonist drug treatment (2-18 hr) followed by a series of cell washes and incubations (Figure 1). AC-isoform specific cAMP accumulation protocols were then employed followed by measurement of cAMP accumulation using a laborious and time consuming [3H]cAMP binding methodology15,24. The duration from start to finish for each assay generally required a total of four to five days from cell plating to data analysis (Figure 1). The application of new technologies and automation has led to marked enhancements for sensitization studies in the industrial and HTS center setting. For example, a group working with the National Center for Chemical Genomics reported a two day HTS assay procedure for identifying small molecule inhibitors of &#956; opioid receptor induced sensitization in 1,536-well format25.
The present article describes our efforts to develop an HTS assay for studies of heterologous sensitization using technologies that are available at most academic research institutions. This strategy was accomplished by incorporating the use of cryopreserved cells from cell models heterologously expressing the D2 dopamine receptor in combination with endogenous or individual recombinant adenylyl cyclase isoforms (CHO-D2L or HEK-AC6/D2L). To improve our throughput, we redesigned our 48 well sensitization assay (ca. &#62;20 steps over 4-5 days) to a five-step, single day assay in 384-well format that was essentially "mix and read". The new format uses a commercially available homogenous time resolved fluorescence (HTRF) assay to measure cAMP accumulation in intact cells with a multi mode plate reader. The assay is robust and amenable to small molecule screening, and can be effectively applied to screen for inhibitors of heterologous sensitization. In addition, we provide data that allows the use of this assay with reverse transfection of siRNA for targeted or genome wide siRNA library screening with only a minor modification to the general approach.

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			<td height="28" style="height:28px;width:205px;">CHO-K1-DRD2L cells</td>
			<td style="width:144px;">DiscoveRx</td>
			<td style="width:148px;">930579C2</td>
			<td style="width:199px;"></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Ham&#8217;s F12 media</td>
			<td style="width:144px;">VWR</td>
			<td style="width:148px;">SH30026fs</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Fetal Bovine Serum</td>
			<td style="width:144px;">VWR</td>
			<td style="width:148px;">SH3007003</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">G418</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">A1720</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Hygromycin</td>
			<td style="width:144px;">Fisher</td>
			<td style="width:148px;">50-230-5556</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Penicillin/ streptomycin</td>
			<td style="width:144px;">Life Technologies</td>
			<td style="width:148px;">15070063</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">15 cm dishes</td>
			<td style="width:144px;">BD Falcon</td>
			<td style="width:148px;">353025</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">DMSO</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">D2650</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Cell dissociation buffer</td>
			<td style="width:144px;">Life Technologies</td>
			<td style="width:148px;">13150016</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Phosphate Buffered Saline</td>
			<td style="width:144px;">Life Technologies</td>
			<td style="width:148px;">10010-049</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Cryovials</td>
			<td style="width:144px;">Fisher</td>
			<td style="width:148px;">976171</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Opti-MEM</td>
			<td style="width:144px;">Life Technologies</td>
			<td style="width:148px;">31985070</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">TC treated 384 well plates</td>
			<td style="width:144px;">Perkin-Elmer</td>
			<td style="width:148px;">6007688</td>
			<td></td>
		</tr>
		<tr height="66">
			<td height="66" style="height:66px;width:205px;">HTRF cAMP Dynamic 2 kit</td>
			<td style="width:144px;">Cisbio Bioassays</td>
			<td style="width:148px;">62AM4PEB</td>
			<td style="width:199px;">http://www.htrf.com/camp-cell-based-assay</td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Synergy 4</td>
			<td style="width:144px;">Biotek</td>
			<td style="width:148px;">H4MLFPTAD</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Prism 6</td>
			<td style="width:144px;">GraphPad Software</td>
			<td style="width:148px;">NA</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">3-Isobutyl-1-methylxanthine</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">I5879</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">(&#177;)Quinpirole</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">Q111</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Spiperone</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">S7395</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Clozapine</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">C6305</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Haloperidol</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">H1512</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">S-(-)Sulpiride</td>
			<td style="width:144px;">Sigma</td>
			<td style="width:148px;">S112</td>
			<td></td>
		</tr>
		<tr height="55">
			<td height="55" style="height:55px;width:205px;">Lipofectamine2000 transfection reagent</td>
			<td style="width:144px;">Invitrogen</td>
			<td style="width:148px;">11668019</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Trypan blue</td>
			<td style="width:144px;">Life Technologies</td>
			<td style="width:148px;">T10282</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Water, DNase, RNase-free</td>
			<td style="width:144px;">MP Biomedicals</td>
			<td style="width:148px;">821739</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Gas siRNA</td>
			<td style="width:144px;">Dharmacon</td>
			<td style="width:148px;">custom siRNA</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">Non-targeting siRNA control</td>
			<td style="width:144px;">Dharmacon</td>
			<td style="width:148px;">D-001206-14-20</td>
			<td></td>
		</tr>
		<tr height="28">
			<td height="28" style="height:28px;width:205px;">siGlo Red</td>
			<td style="width:144px;">Dharmacon</td>
			<td style="width:148px;">D-001630-02</td>
			<td></td>
		</tr>
	</tbody>
</table>

drug-induced sensitization of adenylyl cyclase: assay streamlining and miniaturization for small molecule and sirna screening applications

Sensitization of adenylyl cyclase (AC) signaling has been implicated in a variety of neuropsychiatric and neurologic disorders including substance abuse and Parkinson&#39;s disease. Acute activation of G&#945;i/o-linked receptors inhibits AC activity, whereas persistent activation of these receptors results in heterologous sensitization of AC and increased levels of intracellular cAMP. Previous studies have demonstrated that this enhancement of AC responsiveness is observed both in vitro and in vivo following the chronic activation of several types of G&#945;i/o-linked receptors including D2 dopamine and &#956; opioid receptors. Although heterologous sensitization of AC was first reported four decades ago, the mechanism(s) that underlie this phenomenon remain largely unknown. The lack of mechanistic data presumably reflects the complexity involved with this adaptive response, suggesting that nonbiased approaches could aid in identifying the molecular pathways involved in heterologous sensitization of AC. Previous studies have implicated kinase and Gb&#947; signaling as overlapping components that regulate the heterologous sensitization of AC. To identify unique and additional overlapping targets associated with sensitization of AC, the development and validation of a scalable cAMP sensitization assay is required for greater throughput. Previous approaches to study sensitization are generally cumbersome involving continuous cell culture maintenance as well as a complex methodology for measuring cAMP accumulation that involves multiple wash steps. Thus, the development of a robust cell-based assay that can be used for high throughput screening (HTS) in a 384&#160;well format would facilitate future studies. Using two D2 dopamine receptor cellular models (i.e.&#160;CHO-D2L and HEK-AC6/D2L), we have converted our 48-well sensitization assay (&#62;20 steps 4-5 days) to a five-step, single day assay in 384-well format. This new format is amenable to small molecule screening, and we demonstrate that this assay design can also be readily used for reverse transfection of siRNA in anticipation of targeted siRNA library screening.

Part I. Developing a 384 well heterologous sensitization assay for identifying small molecule inhibitors using a commercially available cell model.
To study heterologous sensitization in a cell model, we made a number of improvements that enabled us to streamline the assay into a "mix and read" format. Several of the key modifications are highlighted below, and are described in more detail in the discussion. The first key step was modifying our cell culture from continuously c...

Watch this Scientific Journal Video about Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications at JoVE.com

Drug-induced Sensitization of Adenylyl Cyclase: Assay Streamlining and Miniaturization for Small Molecule and siRNA Screening Applications

Persistent activation of inhibitory G protein-coupled receptors results in sensitization of adenylyl cyclase signaling. To identify the essential molecular pathways, nonbiased approaches are necessary; however, this strategy requires the development of a scalable cell-based cAMP sensitization assay. Herein, we describe a sensitization assay for small molecule and siRNA screening.

Sensitization of adenylyl cyclase (AC) signaling has been implicated in a variety of neuropsychiatric and neurologic disorders including substance abuse ...

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