Name: saturated fatty acids induce ceramide-associated macrophage cell death
Uploaded: 2017-10-31T15:00:00
Description: Watch this Scientific Journal Video about Saturated Fatty Acids Induce Ceramide-associated Macrophage Cell Death at JoVE.com

This work was supported partially by the University of Louisville start-up funds and National Cancer Institute (Bethesda, MD) grants R01CA177679, R01CA180986.

The protocol was approved by the Institutional Animal Care and Use Committee (IACUC) of University of Louisville.
1. Mouse Bone Marrow Derived Macrophages (BMDMs)
<ol>
	<li>Euthanize a 6- to 8-week-old, healthy wild type mouse using CO2. Pin it down to a foam board and spray it with 70% ethanol until it is soaked. Remove the tibia/femur bones with forceps and scissors. Put them in a petri dish with 5 mL 1x phosphate-buffered saline (PBS). Perform all procedures under sterile condi...

<ol>
	<li>Martins de Lima, T., Cury-Boaventura, M. F., Giannocco, G., Nunes, M. T., Curi, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+toxicity+of+fatty+acids+on+a+macrophage+cell+line+(J774).">Comparative toxicity of fatty acids on a macrophage cell line (J774).</a> Clin Sci (Lond). 111 (5), 307-317 (2006).</li><li>Simard, J. R., Zunszain, P. A., Hamilton, J. A., Curry, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Location+of+high+and+low+affinity+fatty+acid+binding+sites+on+human+serum+albumin+revealed+by+NMR+drug-competition+analysis.">Location of high and low affinity fatty acid binding sites on human serum albumin revealed by NMR drug-competition analysis.</a> J Mol Biol. 361 (2), 336-351 (2006).</li><li>Penn, A. H., Dubick, M. A., Torres Filho, I. 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The proper preparation of fatty acid solution is of critical importance to study the biological function of fatty acids. The neutralization of fatty acid increases its solubility in aqueous solution. However, sodium salts of fatty acids, especially saturated fatty acids, are still of low solubility in water or PBS as we observed. One method is to use 95 - 100% ethanol to help dissolve fatty acid1. Using this method, higher toxicity to cells may be observed even at lower concentrations for less tox...

Fatty acids play a critical role in energy metabolism and in the synthesis of membrane phospholipids in different kinds of cells. Fatty acids have a low aqueous solubility. Appropriate preparation of fatty acid is of critical importance for studying the biological functions of fatty acids in mammalian cells. When fatty acids are prepared with ethanol, many fatty acids may show their toxic soap (detergent) effect on the cell membrane, even at relatively low concentrations1. As a natural, major transporter for free fatty acids in the serum, serum albumin is considered a good carrier for fatty acid delivery in vitro for fatty acid function assays2,3,4. However, the details of the preparation of fatty acid and serum albumin conjugate are usually not available even though many research papers using fatty acids have been published.
Macrophages highly express epidermal fatty acid-binding protein and adipose fatty acid-binding protein5,6,7,8. They actively uptake saturated and unsaturated fatty acids which may regulate their immune functions. To study the impact of fatty acids on macrophages and other cells, different methods of fatty acid preparation were applied1,7,9. Using appropriately prepared fatty acid/serum albumin conjugates to investigate the impact of fatty acids on macrophage function is of critical importance in obtaining biologically meaningful data. Studies on the impact of fatty acids on macrophage function can provide basic knowledge and potential therapeutic targets relating to fatty acid metabolism in macrophage-involved diseases.

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		<tr height="20">
			<td height="20" style="width:357px;height:20px;">CPX Ultrasonic Bath&#160;</td>
			<td style="width:208px;">Bransonic</td>
			<td style="width:153px;">Model 2800</td>
			<td style="width:111px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium palmitate (PA)</td>
			<td>Nu-Chek Prep, Inc.</td>
			<td>S-1109</td>
			<td>M.W. 278</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium stearate (SA)</td>
			<td>Nu-Chek Prep, Inc.</td>
			<td>S-1111</td>
			<td>M.W. 306</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Bovine serum albumin (BSA), fatty acid-free</td>
			<td>Fisher Scientific</td>
			<td>9048-46-8</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Mouse macrophage colony stimulating factor (mM-CSF)&#160;</td>
			<td>Cell Signaling Technology,&#160; Inc.</td>
			<td>5228</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">RPMI 1640</td>
			<td>VWR International</td>
			<td>71002-878</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Annexin V, Alexa Fluor 488 conjugate</td>
			<td>Fisher Scientific</td>
			<td>A13201</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">7-AAD</td>
			<td>BD Biosciences</td>
			<td>559925</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Monoclonal anti-ceramide antibody (mouse IgM)</td>
			<td>Sigma</td>
			<td>C8104-50TST</td>
			<td>Clone: MID 15B4</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Goat Anti-Mouse IgM Antibody, &#181; chain, FITC conjugate</td>
			<td>Sigma</td>
			<td>AP128F</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Fixation buffer</td>
			<td>Biolegend</td>
			<td>420801</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Permeabilization buffer</td>
			<td>Ebioscience</td>
			<td>4307693</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Red Blood Cell Lysis Buffer&#160;</td>
			<td>Sigma</td>
			<td>11814389001</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Annexin V Binding Buffer</td>
			<td>BD Biosciences</td>
			<td>556454</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">L929 cells</td>
			<td>ATCC</td>
			<td>CCL-1</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Corning&#160;Cell Lifter&#160;</td>
			<td>Fisher Scientific</td>
			<td>07-200-364</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="width:357px;height:21px;">Note: M.W. is for molecular weight.</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

saturated fatty acids induce ceramide-associated macrophage cell death

Macrophages highly express epidermal fatty acid-binding protein and adipose fatty acid-binding protein. They actively uptake saturated and unsaturated fatty acids, which might play a critical role in regulating their immune functions. Numerous studies have shown that various fatty acids, saturated or unsaturated, may possess different impacts on cell growth and function. However, the approaches used for fatty acid preparation vary, which may lead to non-physiological results. Serum albumin, a natural carrier for fatty acids in mammalian peripheral blood, is recommended for forming a conjugate complex with the sodium salt of fatty acids to study fatty acid function in mammalian cells, thus minimizing the toxicity of fatty acid soap. Thus, a simple, relatively quick heating and sonicating method is developed and presented here for BSA-fatty acid conjugate formation. We describe a protocol using saturated fatty acids, especially stearic acids to induce severe cell death in mouse bone-marrow derived macrophages. We further demonstrate that saturated fatty acid-induced cell death is positively associated with accumulated cellular ceramide levels. This method can be extended for studies of the impact of fatty acid on other mammalian cells.

Obesity increases free fatty acid concentrations in serum. As professional phagocytes, macrophages actively take up fatty acids to maintain host homeostasis. During these processes, overloaded lipids may induce macrophage cell death. To this end, we cultured BMDMs in vitro with obese levels of dietary fatty acids and measured macrophage cell death using flow cytometric staining. Compared to the BSA control, saturated fatty acids, in particular stearic acids, induced significant c...

Watch this Scientific Journal Video about Saturated Fatty Acids Induce Ceramide-associated Macrophage Cell Death at JoVE.com

Saturated Fatty Acids Induce Ceramide-associated Macrophage Cell Death

We illustrate a straight-forward method to derive murine primary macrophages from bone marrow cells and a simple method to prepare BSA-fatty acid conjugates. Then we demonstrate that saturated fatty acids can induce macrophage cell death, and such cell death is positively associated with cellular accumulation of ceramide levels.

Macrophages highly express epidermal fatty acid-binding protein and adipose fatty acid-binding protein. They actively uptake saturated and unsaturated ...

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