This work was supported by Adelphi University faculty development grant and grant R15GM113156 from NIGMS awarded to EVC, grant R01GM067862 from NIGMS and grant R01AG027849 from NIA awarded to DMR.

1. Reagents and Solutions
<ol>
	<li>Preparation of fly food and media
	<ol>
		<li>Heat fly ingredients 11% sugar, 2% autolyzed yeast, 5.2% cornmeal, agar 0.79% w/v in water in a hotplate set at 90 &#176;C. Stir regularly until a homogenous slightly dense mixture is obtained. Prepare a final volume of 550 ml of fly food for a total of 100 vials with 5 ml fly food in each.</li>
		<li>Remove from the heating source, stir occasionally until the food cools down to 80 &#176;C and add 0.2% tegosept-methyl 4-hydroxybenzoate di...

<ol>
	<li>Scheffler, I. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Mitochondria (Scheffler, Mitochondria). , 484 (2007).</li><li>Guarente, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondria--a+nexus+for+aging,+calorie+restriction,+and+sirtuins.">Mitochondria--a nexus for aging, calorie restriction, and sirtuins.</a> Cell. 132 (2), 171-176 (2008).</li><li>Raimundo, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+pathology:+stress+signals+from+the+energy+factory.">Mitochondrial pathology: stress signals from the energy factory.</a> Trends in molecular medicine. 20 (5), 282-292 (2014).</li><li>Embley, T. M., Martin, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eukaryotic+evolution,+changes+and+challenges.">Eukaryotic evolution, changes and challenges.</a> Nature. 440 (7084), 623-630 (2006).</li><li>Lane, N., , <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Power, Sex, Suicide: Mitochondria and the Meaning of Life. 368, (2006).</li><li>Montooth, K. L., Meiklejohn, C. D., Abt, D. N., Rand, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial-nuclear+epistasis+affects+fitness+within+species+but+does+not+contribute+to+fixed+incompatibilities+between+species+of+Drosophila.">Mitochondrial-nuclear epistasis affects fitness within species but does not contribute to fixed incompatibilities between species of Drosophila.</a> Evolution; international journal of organic evolution. 64 (12), 3364-3379 (2010).</li><li>Villa-Cuesta, E., Holmbeck, M. A., Rand, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapamycin+increases+mitochondrial+efficiency+by+mtDNA-dependent+reprogramming+of+mitochondrial+metabolism+in+Drosophila.">Rapamycin increases mitochondrial efficiency by mtDNA-dependent reprogramming of mitochondrial metabolism in Drosophila.</a> Journal of cell science. 127 (Pt 10), 2282-2290 (2014).</li><li>Zhu, C. -. T., Ingelmo, P., Rand, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=G&#215;G&#215;E+for+Lifespan+in+Drosophila:+Mitochondrial,+Nuclear,+and+Dietary+Interactions+that+Modify+Longevity.">G&#215;G&#215;E for Lifespan in Drosophila: Mitochondrial, Nuclear, and Dietary Interactions that Modify Longevity.</a> PLoS genetics. 10 (5), e1004354 (2014).</li><li>Madala, N. E., Piater, L. A., Steenkamp, P. A., Dubery, I. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multivariate+statistical+models+of+metabolomic+data+reveals+different+metabolite+distribution+patterns+in+isonitrosoacetophenone-elicited+Nicotiana+tabacum+and+Sorghum+bicolor+cells.">Multivariate statistical models of metabolomic data reveals different metabolite distribution patterns in isonitrosoacetophenone-elicited Nicotiana tabacum and Sorghum bicolor cells.</a> SpringerPlus. 3, 254 (2014).</li><li>Hogeboom, G. H., Schneider, W. C., Pallade, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cytochemical+Studies+Of+Mammalian+Tissues+I+.+Isolation+Of+Intact+Mitochondria+From+Rat+Liver+Some+Biochemical+Properties+Of+Mitochondria+And+Submicroscopic+Particulate+Material.">Cytochemical Studies Of Mammalian Tissues I . Isolation Of Intact Mitochondria From Rat Liver Some Biochemical Properties Of Mitochondria And Submicroscopic Particulate Material.</a> Journal of Biological Chemistry. 172, 619-635 (1948).</li><li>Frezza, C., Cipolat, S., Scorrano, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organelle+isolation:+functional+mitochondria+from+mouse+liver,+muscle+and+cultured+fibroblasts.">Organelle isolation: functional mitochondria from mouse liver, muscle and cultured fibroblasts.</a> Nature protocols. 2 (2), 287-295 (2007).</li><li>Corcelli, A., Saponetti, M. 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=Mitochondria+isolated+in+nearly+isotonic+KCl+buffer:+focus+on+cardiolipin+and+organelle+morphology.">Mitochondria isolated in nearly isotonic KCl buffer: focus on cardiolipin and organelle morphology.</a> Biochimica et biophysica acta. 1798 (3), 681-687 (2010).</li><li>Roede, J. R., Park, Y., Li, S., Strobel, F. H., Jones, D. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Detailed+mitochondrial+phenotyping+by+high+resolution+metabolomics.">Detailed mitochondrial phenotyping by high resolution metabolomics.</a> PloS one. 7 (3), e33020 (2012).</li></ol>

The most critical steps in this protocol are: 1) rearing enough flies in abundant space. It is very important to not overpopulate the demography cages with more than 150 flies each; 2) changing the food of the cages frequently to avoid food competition and nutritional stress; and 3) maintaining all samples at 4 &#176;C to ensure integrity during the isolation of the mitochondrial fraction. It is also recommended to chill the isolation buffer, the wash buffer, and the glass-teflon dounce homogenizer before use. To reduce ...

The goal of this procedure is to develop enriched mitochondrial fractions that yield enough mitochondrial metabolites for metabolomics studies using Drosophila melanogaster. In our experience, metabolomics analysis using whole cellular extraction methods are unable to detect subtle mitochondrial metabolite changes in Drosophila. However, mitochondrial fractioning prior to metabolomics analysis increases the sensitivity to identify mitochondrial metabolite shifts.
Mitochondria are cellular organelles responsible for providing 90% of the energy that cells need for normal function1. In recent years it has been recognized that mitochondria play a much more dynamic role in cellular and organismal function than merely producing adenosine triphosphate(ATP), and are now recognized as hubs for the regulation of metabolic homeostasis2,3. Mitochondria are the result of an endosymbiotic process in which distinct microbial lineages merged ~1.5 billion years ago4. As mitochondria evolved into true organelles, genes from the endosymbiont were incorporated in the emerging nuclear genome. In animals today, approximately 1,500 mitochondrial proteins are nuclear-encoded while 37 genes remain in the mtDNA, 13 of which encode mitochondrial proteins that are subunits of the enzyme complexes of oxidative phosphorylation5. Coordination between mitochondria and nuclear compartments is needed to maintain proper mitochondrial function.
Using the methods described here we were able to detect mitochondrial metabolic changes in Drosophila that result from manipulation of the coordination between mitochondrial and nuclear genomes. We used a strain of Drosophila in which mtDNA from its sister species D. simulans was placed on a single D. melanogaster nuclear background6. This &#8216;disrupted&#8217; mitonuclear genotype was compared to the &#8216;native&#8217;, or co-evolved mitonuclear genotype of D. melanogaster carrying the same nuclear genome with its native D. melanogaster mtDNA. The D. melanogaster and D. simulans mtDNAs differ by ~100 amino acids and &#62;500 synonymous substitutions that affect mitonuclear communication7,8. We generated whole fly extracts and mitochondrial enriched extracts to study metabolite shifts in response to pharmacological stress. Here we show that when using mitochondrial enriched fractions we detect pronounced shifts in mitochondrial metabolites between the native, co-evolved genotype carrying the D. melanogaster mtDNAs and the disrupted genotype carrying D. simulans mtDNA. In contrast, the metabolite changes between these two genotypes are subtle using normal methods that utilize whole fly extract. Therefore, this method provided a path to understand how mtDNAs mediate mitochondrial changes in response to different drugs.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>0.2% tegosept -methyl 4-hydroxybenzoate&#160;</td>
			<td>VWR</td>
			<td>AAA14289</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Sigma-Aldrich</td>
			<td>792799</td>
			<td></td>
		</tr>
		<tr>
			<td>Mannitol</td>
			<td>Sigma-Aldrich</td>
			<td>M4125</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma-Aldrich</td>
			<td>S9378</td>
			<td></td>
		</tr>
		<tr>
			<td>3-(N-morpholino) propanesulfonic acid (MOPS)</td>
			<td>Sigma-Aldrich</td>
			<td>M1254&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethylenediaminetetraacetic acid (EDTA)</td>
			<td>Sigma-Aldrich</td>
			<td>38057&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin (BSA)</td>
			<td>Sigma-Aldrich</td>
			<td>5470</td>
			<td></td>
		</tr>
		<tr>
			<td>KCL</td>
			<td>Sigma-Aldrich</td>
			<td>P9333</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris HCL&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>RES3098T-B7</td>
			<td></td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma-Aldrich</td>
			<td>1551139</td>
			<td></td>
		</tr>
		<tr>
			<td>CO2 pads to anesthetize flies</td>
			<td>Tritech Research</td>
			<td>MINJ-DROS-FP</td>
			<td></td>
		</tr>
		<tr>
			<td>1 liter cage&#160;</td>
			<td>Web Restaurant Store</td>
			<td>999RD32</td>
			<td></td>
		</tr>
		<tr>
			<td>1 liter cage lid&#160;</td>
			<td>Web Restaurant Store</td>
			<td>999LRD</td>
			<td></td>
		</tr>
		<tr>
			<td>a glass-teflon dounce homogenizer&#160;</td>
			<td>Fisher Scientific</td>
			<td>NC9661231</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Sigma-Aldrich</td>
			<td>S8045</td>
			<td></td>
		</tr>
		<tr>
			<td>rapamycin&#160;</td>
			<td>LC Laboratories&#160;</td>
			<td>R-5000</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-porin</td>
			<td>MitoSciences</td>
			<td>MSA03</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-alpha tubulin</td>
			<td>Developmental Studies Hybridoma Bank</td>
			<td>12G10</td>
			<td></td>
		</tr>
		<tr>
			<td>Pierce&#8482; BCA Protein Assay Kit&#160;</td>
			<td>Thermo Scientific&#160;</td>
			<td>23225</td>
			<td></td>
		</tr>
		<tr>
			<td>CO2 pad</td>
			<td>Tritech Research, Inc</td>
			<td>MINJ-DROS-FP</td>
			<td></td>
		</tr>
		<tr>
			<td>filter flask</td>
			<td>enasco</td>
			<td>SB08184M</td>
			<td></td>
		</tr>
		<tr>
			<td>rubber stopper</td>
			<td>enasco</td>
			<td>S08512M</td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation of mitochondrial enriched fractions for metabolic analysis in drosophila

Since mitochondria play roles in amino acid metabolism, carbohydrate metabolism and fatty acid oxidation, defects in mitochondrial function often compromise the lives of those who suffer from these complex diseases. Detecting mitochondrial metabolic changes is vital to the understanding of mitochondrial disorders and mitochondrial responses to pharmacological agents. Although mitochondrial metabolism is at the core of metabolic regulation, the detection of subtle changes in mitochondrial metabolism may be hindered by the overrepresentation of other cytosolic metabolites obtained using whole organism or whole tissue extractions. 
Here we describe an isolation method that detected pronounced mitochondrial metabolic changes in Drosophila that were distinct between whole-fly and mitochondrial enriched preparations. To illustrate the sensitivity of this method, we used a set of Drosophila harboring genetically diverse mitochondrial DNAs (mtDNA) and exposed them to the drug rapamycin. Using this method we showed that rapamycin modifies mitochondrial metabolism in a mitochondrial-genotype-dependent manner. However, these changes are much more distinct in metabolomics studies when metabolites were extracted from mitochondrial enriched fractions. In contrast, whole tissue extracts only detected metabolic changes mediated by the drug rapamycin independently of mtDNAs.

Using the protocol explained above, we performed metabolomic analysis on mitochondrial enriched fractions and whole animal extracts to test the effect of the drug rapamycin on divergent mtDNAs 7. We delivered 200 &#181;M of rapamycin by dissolving the drug in the fly food. Flies were exposed to rapamycin for 10 days. Metabolites from whole fly extracts and from mitochondrial extracts were obtained by using gas chromatography mass spectrometry (GC/MS) and liquid chromatogra...

Watch this Scientific Journal Video about Preparation of Mitochondrial Enriched Fractions for Metabolic Analysis in Drosophila at JoVE.com

Preparation of Mitochondrial Enriched Fractions for Metabolic Analysis in Drosophila

Mitochondria play central roles in the regulation of metabolism and homeostasis. Subtle changes in mitochondrial metabolism that affect organismal physiology could be difficult to detect in whole organism metabolomics studies. Here we describe an isolation method that enhances the detection of subtle metabolic shifts in Drosophila melanogaster.

Preparation of Mitochondrial Enriched Fractions for Metabolic Analysis in Drosophila

Since mitochondria play roles in amino acid metabolism, carbohydrate metabolism and fatty acid oxidation, defects in mitochondrial function often ...

preparation-mitochondrial-enriched-fractions-for-metabolic-analysis

Research

JoVE Journal

Developmental Biology

9.4K vistas.  Adelphi University. Mitochondria play central roles in the regulation of metabolism and homeostasis. Subtle changes in mitochondrial metabolism that affect organismal physiology could be difficult to detect in whole organism metabolomics studies. Here we describe an isolation method that enhances the detection of subtle metabolic shifts in Drosophila melanogaster. 