Name: quantification of lipid abundance and evaluation of lipid distribution in caenorhabditis elegans by nile red and oil red o staining
Uploaded: 2018-03-05T14:00:00
Description: Watch this Scientific Journal Video about Quantification of Lipid Abundance and Evaluation of Lipid Distribution in Caenorhabditis elegans by Nile Red and Oil Red O Staining at JoVE.com

This work was made possible by the NIH grant: R01GM109028 (S.P.C.)

1. Nile Red (NR) Staining of Lipids
<ol>
	<li>Preparation of 5 mg/mL NR stock solution
	<ol>
		<li>In a 500 mL bottle, add 100 mg of NR powder to 200 mL of 100% acetone.</li>
		<li>Cover the bottle with aluminum foil to avoid any exposure to light.</li>
		<li>Before use, stir the solution for 2 h in the dark.</li>
		<li>For long term use, store the NR stock solution in a tightly sealed bottle without any light exposure. Scale NR stock solution according to research needs. Ensure that the same stock solution is used acr...

<ol>
	<li>Greenspan, P., Mayer, E. P., Fowler, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nile+red:+a+selective+fluorescent+stain+for+intracellular+lipid+droplets.">Nile red: a selective fluorescent stain for intracellular lipid droplets.</a> J Cell Biol. 100 (3), 965-973 (1985).</li><li>Guo, Y., Cordes, K. R., Farese, R. V., Walther, 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=Lipid+droplets+at+a+glance.">Lipid droplets at a glance.</a> J Cell Sci. 122 (6), 749-752 (2009).</li><li>Horobin, R. W., Kiernan, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Conn's biological stains: a handbook of dyes, stains and fluorochromes for use in biology and medicine. , (2002).</li><li>Hulme, S. 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R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Insulin+signalling+and+the+regulation+of+glucose+and+lipid+metabolism.">Insulin signalling and the regulation of glucose and lipid metabolism.</a> Nature. 414 (6865), 799-806 (2001).</li><li>Witting, M., Schmitt-Kopplin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Caenorhabditis+elegans+lipidome:+A+primer+for+lipid+analysis+in+Caenorhabditis+elegans.">The Caenorhabditis elegans lipidome: A primer for lipid analysis in Caenorhabditis elegans.</a> Arch Biochem Biophys. 589, 27-37 (2016).</li><li>Yen, K., Le, T. T., Bansal, A., Narasimhan, S. D., Cheng, J. X., Tissenbaum, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+comparative+study+of+fat+storage+quantitation+in+nematode+Caenorhabditis+elegans+using+label+and+label-free+methods.">A comparative study of fat storage quantitation in nematode Caenorhabditis elegans using label and label-free methods.</a> PloS One. 5 (9), e12810 (2010).</li><li>Zhang, Y., Zou, X., Ding, Y., Wang, H., Wu, X., Liang, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+genomics+and+functional+study+of+lipid+metabolic+genes+in+Caenorhabditis+elegans.">Comparative genomics and functional study of lipid metabolic genes in Caenorhabditis elegans.</a> BMC Genomics. 14 (1), 164 (2013).</li><li>Folick, A., Min, W., Wang, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Label-free+imaging+of+lipid+dynamics+using+Coherent+Anti-stokes+Raman+Scattering+(CARS)+and+Stimulated+Raman+Scattering+(SRS)+microscopy.">Label-free imaging of lipid dynamics using Coherent Anti-stokes Raman Scattering (CARS) and Stimulated Raman Scattering (SRS) microscopy.</a> Curr Opin Genet Dev. 21 (5), 585-590 (2011).</li><li>Pino, E. C., Webster, C. M., Carr, C. E., Soukas, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biochemical+and+high+throughput+microscopic+assessment+of+fat+mass+in+Caenorhabditis+elegans.">Biochemical and high throughput microscopic assessment of fat mass in Caenorhabditis elegans.</a> J Vis Exp. (73), (2013).</li><li>O'Rourke, E. J., Soukas, A. A., Carr, C. 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The rise in obesity and metabolic disease rates makes C. elegans a suitable model to study the mechanisms that regulate fat accumulation in cells and tissues. Recent evidence suggests that the changes in lipid levels are correlated with cellular processes ranging from insulin signaling8, the activation of hormone receptors2, to reproductive output5. Compared to label-free microscopy and chromatography methods, Nile red and oil red O are rela...

Lipids are essential for life. They are integral components of membranes, act as secondary messengers and signal transducers, and have crucial functions in energy storage. When lipid metabolism is dysregulated, it leads to diseases like obesity and type II diabetes, which are pressing public health concerns9. Caenorhabditis elegans (C. elegans) is an excellent model organism in which to study lipid metabolism because it has a relatively short life cycle, a transparent body, a known cell lineage, and a fully sequenced genome. Primarily a hermaphrodite, C. elegans allows researchers to raise large numbers of isogenic animals in short periods of time to carryout high-throughput forward genetic screens to study a wide array of metabolic genes and pathways4. This approach has revealed a high degree of conservation in 273 C. elegans lipid metabolism genes among humans, mice, rats and drosophila. Furthermore, over 300 lipid genes in C. elegans have human orthologues that are associated with diseases unrelated to metabolic syndrome11. Traditionally, examination of lipid storage in C. elegans has mostly relied on dye-labeled assays, which provide robust information about lipid accumulation. Less common is a description of where lipids localize and measured differences in lipid abundance across tissues. However, recent work has revealed that lipid distribution can be as important as lipid accumulation6.
Lately, studies have begun integrating methods such as high performance liquid chromatography-mass spectrometry (HPLC-MS), gas chromatography-mass spectrometry (GC-MS), and coherent anti-stokes Raman scattering (CARS) microscopy to address the shortcomings of stain-based approaches by directly analyzing the contents of lipid extracts, specific lipid fractions, and lipid deposits, respectively10,11. Moreover, CARS microscopy has revealed that Nile red can only serve as a proxy for fat accumulation when used as a fixative dye, for its use as a vital stain leads to off-target staining of auto-fluorescent organelles10. However, the required technical expertise and costs associated with these chromatography and microscopy methods make their use untenable for many research questions. In this article, we discuss a convenient and reliable method to fixate and stain neutral lipid deposits in C. elegans using Nile red and oil red O to distinguish lipid abundance in whole animals and in specific tissues.
Nile red, 9-diethylamino-5H-benzo[&#945;]phenoxazine-5-one, is a benzophenoxazone dye that readily dissolves in various organic solvents, but is mostly insoluble in water. It is an excellent lysochrome dye used to stain neutral lipids such as triglycerides or cholesterol esters because it features a strong color, solubilizes well in lipids, has negligible interaction with surrounding tissues, and is less soluble in the solvent than in lipids. It has an excitation and emission maxima of 450-500 and 520 nm, respectively1. When Nile red-stained C. elegans is viewed for green fluorescence, discrete lipid bodies can be observed throughout the intestine and other tissues either in clusters or evenly dispersed, depending on the animal&#39;s genotype or experimental treatment7.
Oil red O is a lysochrome, fat-soluble dye used to stain triglycerides and lipoproteins. It is called an azo dye because its chemical structure contains two azo groups attached to three aromatic rings. It is difficult to ionize, which renders it highly soluble in lipids. Its stain color is red and its light absorption maximum is 518 nm 3. C. elegans stained with oil red O show red lipid droplets that stand out against the animal&#39;s transparent body, which facilitates qualitative assessment of lipid distribution among different tissues6.

<table>
	<tbody>
		<tr>
			<td>Imager.M2m Microscope</td>
			<td>Zeiss</td>
			<td>n/a</td>
			<td>Fluorescence microscope</td>
		</tr>
		<tr>
			<td>ERC5s camera</td>
			<td>Axiocam</td>
			<td>n/a</td>
			<td>Color-capable</td>
		</tr>
		<tr>
			<td>MRm camera</td>
			<td>Axiocam</td>
			<td>n/a</td>
			<td>Fluorescence-capable</td>
		</tr>
		<tr>
			<td>Nile red</td>
			<td>Thermo Fisher</td>
			<td>N1142</td>
			<td>Lipid Stain</td>
		</tr>
		<tr>
			<td>Oil red O</td>
			<td>Alfa Aesar</td>
			<td>A12989</td>
			<td>Lipid Stain</td>
		</tr>
		<tr>
			<td>DAPI</td>
			<td>Thermo Fisher</td>
			<td>D1306</td>
			<td>DNA stain</td>
		</tr>
		<tr>
			<td>Isopropyl Alcohol</td>
			<td>BDH</td>
			<td>BDH1133-1LP</td>
			<td>Fixative solution</td>
		</tr>
		<tr>
			<td>0.2 &#181;m seterile syringe filter</td>
			<td>VWR</td>
			<td>28145-477</td>
			<td>Cellulose acetate filter</td>
		</tr>
		<tr>
			<td>Centrifuge 5430</td>
			<td>Eppendorf</td>
			<td>5428000015</td>
			<td>Centrifuge</td>
		</tr>
		<tr>
			<td>Shaker Rotisserie</td>
			<td>Lab Quake</td>
			<td>400110Q</td>
			<td>Shaker</td>
		</tr>
		<tr>
			<td>Tube Rotator</td>
			<td>VWR</td>
			<td>10136-084</td>
			<td>Rotator</td>
		</tr>
		<tr>
			<td>K2HPO4</td>
			<td>Sigma-Aldrich</td>
			<td>7758-11-4</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma-Aldrich</td>
			<td>7778-77-0</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>MgSO4</td>
			<td>Alfa Aesar</td>
			<td>7786-30-3</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>Sigma-Aldrich</td>
			<td>10035-04-8</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma-Aldrich</td>
			<td>7647-14-5</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>Cholesterol</td>
			<td>Sigma-Aldrich</td>
			<td>57-88-5</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>Peptone</td>
			<td>BD Biosciences</td>
			<td>211677</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>Teknova</td>
			<td>L9110</td>
			<td>NGM</td>
		</tr>
		<tr>
			<td>LB media</td>
			<td>Sigma-Aldrich</td>
			<td>L3147</td>
			<td>Bacterial growth</td>
		</tr>
	</tbody>
</table>

quantification of lipid abundance and evaluation of lipid distribution in caenorhabditis elegans by nile red and oil red o staining

Caenorhabditis elegans is an exceptional model organism in which to study lipid metabolism and energy homeostasis. Many of its lipid genes are conserved in humans and are associated with metabolic syndrome or other diseases. Examination of lipid accumulation in this organism can be carried out by fixative dyes or label-free methods. Fixative stains like Nile red and oil red O are inexpensive, reliable ways to quantitatively measure lipid levels and to qualitatively observe lipid distribution across tissues, respectively. Moreover, these stains allow for high-throughput screening of various lipid metabolism genes and pathways. Additionally, their hydrophobic nature facilitates lipid solubility, reduces interaction with surrounding tissues, and prevents dissociation into the solvent. Though these methods are effective at examining general lipid content, they do not provide detailed information about the chemical composition and diversity of lipid deposits. For these purposes, label-free methods such as GC-MS and CARS microscopy are better suited, their costs notwithstanding.

SKN-1 is a bZip, cytoprotective transcription factor that shares homology with mammalian NRF2 and has been shown to mediate fatty acid oxidation. Depending on the glucose concentration in their diet, worms with a constitutively activated skn-1 allele show different lipid levels when stained with Nile red7. Figure 1A-C shows activated skn-1 animals exposed to conditions that lead to increasing lipid le...

Watch this Scientific Journal Video about Quantification of Lipid Abundance and Evaluation of Lipid Distribution in Caenorhabditis elegans by Nile Red and Oil Red O Staining at JoVE.com

Quantification of Lipid Abundance and Evaluation of Lipid Distribution in Caenorhabditis elegans by Nile Red and Oil Red O Staining

Nile red staining of fixed Caenorhabditis elegans is a method for quantitative measurement of neutral lipid deposits, while oil red O staining facilitates qualitative assessment of lipid distribution among tissues.

Quantification of Lipid Abundance and Evaluation of Lipid Distribution in Caenorhabditis elegans by Nile Red and Oil Red O Staining

Caenorhabditis elegans is an exceptional model organism in which to study lipid metabolism and energy homeostasis. Many of its lipid genes are conserved ...

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