Name: culture of macrophage colony-stimulating factor differentiated human monocyte-derived macrophages
Uploaded: 2016-06-30T15:00:00
Description: Watch this Scientific Journal Video about Culture of Macrophage Colony-stimulating Factor Differentiated Human Monocyte-derived Macrophages at JoVE.com

The Department of Transfusion Medicine, Clinical Center, National Institutes of Health, provided elutriated monocytes. This work was supported by the Intramural Research Program, National Heart, Lung, and Blood Institute, National Institutes of Health.

Leukapheresis was carried out under a human subject&#39;s research protocol approved by a National Institutes of Health institutional review board.
1. Isolation and Cryopreservation of Monocytes
<ol>
	<li>Obtain mononuclear cells by leukapheresis of human donors, and enrich monocytes by continuous counter-flow centrifugation elutriation of mononuclear cells as described in the references 7,8. Obtain approximately 100 x 106 elutriated cells (approximately 80 - 90% monocy...

<ol>
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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+heterogeneity+of+colony-stimulating+factor-induced+human+monocyte-derived+macrophages.">Functional heterogeneity of colony-stimulating factor-induced human monocyte-derived macrophages.</a> Int. J. Hematol. 76, 27-34 (2002).</li><li>Akagawa, K. 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=Functional+heterogeneity+of+colony-stimulating+factor-induced+human+monocyte-derived+macrophages.">Functional heterogeneity of colony-stimulating factor-induced human monocyte-derived macrophages.</a> Respirology. 11 Suppl, S32-S36 (2006).</li><li>Fleetwood, A. J., Lawrence, T., Hamilton, J. A., Cook, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Granulocyte-macrophage+colony-stimulating+factor+(CSF)+and+macrophage+CSF-dependent+macrophage+phenotypes+display+differences+in+cytokine+profiles+and+transcription+factor+activities:+implications+for+CSF+blockade+in+inflammation.">Granulocyte-macrophage colony-stimulating factor (CSF) and macrophage CSF-dependent macrophage phenotypes display differences in cytokine profiles and transcription factor activities: implications for CSF blockade in inflammation.</a> J. Immunol. 178, 5245-5252 (2007).</li><li>Lacey, D. C., 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=Defining+GM-CSF-+and+macrophage-CSF-dependent+macrophage+responses+by+in+vitro+models.">Defining GM-CSF- and macrophage-CSF-dependent macrophage responses by in vitro models.</a> J. Immunol. 188, 5752-5765 (2012).</li><li>Strasser, E. F., Eckstein, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+leukocyte+collection+and+monocyte+isolation+for+dendritic+cell+culture.">Optimization of leukocyte collection and monocyte isolation for dendritic cell culture.</a> Transfus. Med. Rev. 24, 130-139 (2010).</li><li>Kim, 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=Monocyte+enrichment+from+leukapheresis+products+by+using+the+Elutra+cell+separator.">Monocyte enrichment from leukapheresis products by using the Elutra cell separator.</a> Transfusion (Paris). 47, 2290-2296 (2007).</li><li>Strober, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Trypan+blue+exclusion+test+of+cell+viability.">Trypan blue exclusion test of cell viability.</a> Curr. Protoc. Immunol. Appendix 3 (Appendix 3B), (2001).</li><li>Anzinger, J. 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=Native+low-density+lipoprotein+uptake+by+macrophage+colony-stimulating+factor-differentiated+human+macrophages+is+mediated+by+macropinocytosis+and+micropinocytosis.">Native low-density lipoprotein uptake by macrophage colony-stimulating factor-differentiated human macrophages is mediated by macropinocytosis and micropinocytosis.</a> Arterioscler. Thromb. Vasc. Biol. 30, 2022-2031 (2010).</li><li>Zhao, B., 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=Constitutive+receptor-independent+low+density+lipoprotein+uptake+and+cholesterol+accumulation+by+macrophages+differentiated+from+human+monocytes+with+macrophage-colony-stimulating+factor+(M-CSF).">Constitutive receptor-independent low density lipoprotein uptake and cholesterol accumulation by macrophages differentiated from human monocytes with macrophage-colony-stimulating factor (M-CSF).</a> J. Biol. Chem. 281, 15757-15762 (2006).</li><li>Freeman, S. 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=ABCG1-mediated+generation+of+extracellular+cholesterol+microdomains.">ABCG1-mediated generation of extracellular cholesterol microdomains.</a> J. Lipid Res. 55, 115-127 (2014).</li><li>Kruth, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Receptor-independent+fluid-phase+pinocytosis+mechanisms+for+induction+of+foam+cell+formation+with+native+low-density+lipoprotein+particles.">Receptor-independent fluid-phase pinocytosis mechanisms for induction of foam cell formation with native low-density lipoprotein particles.</a> Curr. Opin. Lipidol. 22, 386-393 (2011).</li><li>Jin, X., 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=ABCA1+contributes+to+macrophage+deposition+of+extracellular+cholesterol.">ABCA1 contributes to macrophage deposition of extracellular cholesterol.</a> J. Lipid Res. 56, 1720-1726 (2015).</li><li>Ong, D. 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=Extracellular+cholesterol-rich+microdomains+generated+by+human+macrophages+and+their+potential+function+in+reverse+cholesterol+transport.">Extracellular cholesterol-rich microdomains generated by human macrophages and their potential function in reverse cholesterol transport.</a> J. Lipid Res. 51, 2303-2313 (2010).</li><li>Hashimoto, S., Yamada, M., Motoyoshi, K., Akagawa, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhancement+of+macrophage+colony-stimulating+factor-induced+growth+and+differentiation+of+human+monocytes+by+interleukin-10.">Enhancement of macrophage colony-stimulating factor-induced growth and differentiation of human monocytes by interleukin-10.</a> Blood. 89, 315-321 (1997).</li><li>Hashimoto, S. I., Komuro, I., Yamada, M., Akagawa, K. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=IL-10+inhibits+granulocyte-macrophage+colony-stimulating+factor-dependent+human+monocyte+survival+at+the+early+stage+of+the+culture+and+inhibits+the+generation+of+macrophages.">IL-10 inhibits granulocyte-macrophage colony-stimulating factor-dependent human monocyte survival at the early stage of the culture and inhibits the generation of macrophages.</a> J. Immunol. 167, 3619-3625 (2001).</li><li>Lund, P. K., Joo, G. B., Westvik, A. B., Ovstebo, R., Kierulf, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+monocytes+from+whole+blood+by+density+gradient+centrifugation+and+counter-current+elutriation+followed+by+cryopreservation:+six+years'+experience.">Isolation of monocytes from whole blood by density gradient centrifugation and counter-current elutriation followed by cryopreservation: six years' experience.</a> Scand. J. Clin. Lab. Invest. 60, 357-365 (2000).</li><li>Weiner, R. S., Normann, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+integrity+of+cryopreserved+human+monocytes.">Functional integrity of cryopreserved human monocytes.</a> J. Natl. Cancer Inst. 66, 255-260 (1981).</li><li>Hansen, J. B., 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=Retention+of+phagocytic+functions+in+cryopreserved+human+monocytes.">Retention of phagocytic functions in cryopreserved human monocytes.</a> J. Leukoc. Biol. 57, 235-241 (1995).</li><li>Seager Danciger, 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=Method+for+large+scale+isolation,+culture+and+cryopreservation+of+human+monocytes+suitable+for+chemotaxis,+cellular+adhesion+assays,+macrophage+and+dendritic+cell+differentiation.">Method for large scale isolation, culture and cryopreservation of human monocytes suitable for chemotaxis, cellular adhesion assays, macrophage and dendritic cell differentiation.</a> J. Immunol. Methods. 288, 123-134 (2004).</li><li>Jin, X., Xu, Q., Champion, K., Kruth, H. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endotoxin+contamination+of+apolipoprotein+A-I:+effect+on+macrophage+proliferation--a+cautionary+tale.">Endotoxin contamination of apolipoprotein A-I: effect on macrophage proliferation--a cautionary tale.</a> Atherosclerosis. 240, 121-124 (2015).</li></ol>

Generating defined macrophage types can clarify some of the conflicting results obtained by investigators when studying macrophage biology. The use of various culture conditions and differentiation factors to generate primary human macrophages can lead to very different macrophage types, a fact that may not be appreciated by the researcher. For example, macrophages sometimes are generated from human monocytes using no serum, human serum alone, human serum supplemented with M-CSF, FBS alone, or FBS containing M-CSF or GM-...

Study of cultured macrophages is a useful model to understand the function of these cells in inflammation such as occurs in atherosclerotic plaques. When the research focus is on human diseases involving macrophages, it is useful to study primary human macrophages rather than non-human macrophages to avoid species differences. Also, the effects of cell transformation can be avoided by using primary macrophages rather than macrophage cell lines. For this purpose, macrophages differentiated from monocytes isolated from human blood serve as a means of obtaining primary human macrophages. 
Tissue macrophages may be either resident within tissues or may be derived from monocytes that migrate into the tissue and differentiate into macrophages 1. Two types of human monocyte-derived macrophages have been defined that differ not only in morphology but also gene expression and cell function 2. These two types are obtained from monocytes that are differentiated into macrophages in the presence of M-CSF + fetal bovine serum (FBS) and monocytes that are differentiated into macrophages in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) + FBS 2-6. In our experience (unpublished observation), use of human serum rather than FBS generates the GM-CSF type regardless of whether M-CSF or GM-CSF is included in the differentiation medium. M-CSF type macrophages tend to be more elongated than GM-CSF type macrophages, which resemble fried eggs in their morphology. Investigators should recognize that human M-CSF and GM-CSF monocyte-derived macrophages are not the same as so called M1 and M2 mouse bone marrow-derived macrophages 6.
During research using human monocyte-derived M-CSF differentiated macrophages, we experienced difficulty related to the availability of monocytes to initiate experiments and variation in the obtained cell densities of macrophages during differentiation of monocytes into macrophages. To overcome these problems, we have developed the following protocol in which monocytes are frozen until required for use, and monocytes are differentiated in bulk into macrophages that can then be removed from culture flasks and plated at desired cell densities to obtain more uniform cultures from experiment to experiment.

<table border="0" cellpadding="0" cellspacing="0" width="1086">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">Cellbind 12-well culture plate</td>
			<td style="width:319px;">Corning</td>
			<td style="width:173px;">3336</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">CELLSTAR, T-75 flask, tissue culture treated</td>
			<td style="width:319px;">Greiner Bio-One North America</td>
			<td style="width:173px;">658157</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">RPMI 1640 culture medium</td>
			<td style="width:319px;">Cellgro Mediatech</td>
			<td style="width:173px;">15-040-CM</td>
			<td style="width:167px;">warmed to 37 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">L-Glutamine</td>
			<td style="width:319px;">Cellgro Mediatech</td>
			<td style="width:173px;">25-005-CI</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">Fetal bovine serum</td>
			<td style="width:319px;">Gibco</td>
			<td style="width:173px;">16000-036</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">M-CSF</td>
			<td style="width:319px;">PeproTech</td>
			<td style="width:173px;">300-25</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">GM-CSF</td>
			<td style="width:319px;">PeproTech</td>
			<td style="width:173px;">300-03</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">IL-10&#160;</td>
			<td style="width:319px;">PeproTech</td>
			<td style="width:173px;">200-10</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">DMSO</td>
			<td style="width:319px;">Sigma</td>
			<td style="width:173px;">D2650</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">Cryovial&#160;</td>
			<td style="width:319px;">Thermo Scientific&#160;</td>
			<td style="width:173px;">375418</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:428px;">DPBS without Ca2+ and Mg2+&#160;</td>
			<td style="width:319px;">Corning cellgro</td>
			<td style="width:173px;">21-031-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">0.25% Trypsin-EDTA&#160;</td>
			<td style="width:319px;">Gibco</td>
			<td style="width:173px;">25200-056</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">50 ml polypropylene conical tube</td>
			<td style="width:319px;">Falcon</td>
			<td style="width:173px;">352070</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">Trypan Blue</td>
			<td style="width:319px;">Lonza</td>
			<td style="width:173px;">17-942E</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">Neubauer-improved bright light hemocytometer&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td style="width:319px;">Paul Marienfeld GmbH &#38; Co. KG</td>
			<td style="width:173px;">610031</td>
			<td>http://www.marienfeld-superior.com/index.php/counting-chambers/articles/counting-chambers.html</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">CoolCell LX cell freezing container</td>
			<td style="width:319px;">BioCision</td>
			<td style="width:173px;">BCS-405</td>
			<td>other freezing containers also should&#160; be adequate for this step</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:428px;">Liquid Nitrogen Storage System, CryoPlus 1</td>
			<td style="width:319px;">Thermo Scientific&#160;</td>
			<td style="width:173px;">7400</td>
			<td>any liquid nitrogen tank should be adequate</td>
		</tr>
	</tbody>
</table>

culture of macrophage colony-stimulating factor differentiated human monocyte-derived macrophages

A protocol is presented for cell culture of macrophage colony-stimulating factor (M-CSF) differentiated human monocyte-derived macrophages. For initiation of experiments, fresh or frozen monocytes are cultured in flasks for 1 week with M-CSF to induce their differentiation into macrophages. Then, the macrophages can be harvested and seeded into culture wells at required cell densities for carrying out experiments. The use of defined numbers of macrophages rather than defined numbers of monocytes to initiate macrophage cultures for experiments yields macrophage cultures in which the desired cell density can be more consistently attained. Use of cryopreserved monocytes reduces dependency on donor availability and produces more homogeneous macrophage cultures.

The viability of fresh or cryopreserved monocytes was greater than 95% as determined with Trypan Blue staining 9. Figure 1 and Figure 2 compare at lower and higher magnifications, respectively, the progress of fresh and cryopreserved (i.e., frozen) monocyte differentiation into macrophages. Note that the fresh compared with cryopreserved monocytes show a subpopulation of differentiating monocytes that do not spread but...

Watch this Scientific Journal Video about Culture of Macrophage Colony-stimulating Factor Differentiated Human Monocyte-derived Macrophages at JoVE.com

Culture of Macrophage Colony-stimulating Factor Differentiated Human Monocyte-derived Macrophages

A protocol is presented for cell culture of macrophage colony-stimulating factor (M-CSF) differentiated human monocyte-derived macrophages. The protocol utilizes cryopreservation of monocytes coupled with their bulk differentiation into macrophages. Then harvested macrophages can then be seeded into culture wells at required cell densities for carrying out experiments.

A protocol is presented for cell culture of macrophage colony-stimulating factor (M-CSF) differentiated human monocyte-derived macrophages. For initiation ...

The overall goal of this procedure is to improve the availability of monocytes and to minimize the variation in obtained cell densities during MCSF induced differentiation of human blood monocytes into macrophages. This method can help answer key questions concerning human macrophage biology. The main advantage of this tactic is that human monocyte derived macrophage cultures can be readily obtained with reduced dependency on donor availability.In addition desired macrophage cell density and the homogeneous cultures can be consistently achieved. To begin this procedure, obtain the mononuclear cells by leukapheresis from human donors and then enrich the monocytes by continuous counterflow centrifugal elutriation of mononuclear cells. After that, count the cells using a hemocytometer.Next, centrifuge the monocytes in a 15 milliliter polypropylene tube for five minutes at room temperature. Then, remove the supernatant and gently re-suspend the cells in FBS followed by Dimethyl Sulfoxide to achieve a final concentration of 90%FBS, 10%Dimethyl Sulfoxide, and 50 times 10 to the six cells per milliliter. Afterward add one milliliter of cell suspension to an individual cryofile.Place the cryofiles in a cell freezing container, and transfer it to the minus 80 degrees Celsius freezer for 24 hours. After 24 hours, transfer the container to a liquid nitrogen cyrofile tank for long term storage. In this step, thaw a cyrofile of cells by briefly keeping it in a 37 degrees Celsius water bath.When the cell suspension has thawed about 70%remove it from the water bath immediately and transfer it to room temperature. After the cell suspension has been completely thawed, transfer one milliliter of the cyrofile contents to 50 milliliters of RPMI 1640 medium with two millimolar L-glutamine, 50 nanograms per milliliter M-CSF, 25 nanograms per milliliter IL-10, and 10%FBS at 37 degrees Celsius. Then, transfer 25 milliliters of monocyte suspension into two 75 square-centimeter plastic cell culture flasks.Incubate the cultures at 37 degrees Celsius for 48 hours. Remember do not change the medium until 48 hours;otherwise, the cells won't be well attached and will be rinsed away. After 48 hours, rinse the cultures three times with 10 milliliters of pre-warmed RPMI 1640 medium.Gently remove the culture medium to avoid dislodging any loosely attached cells. Subsequently, add complete medium and culture the cells for one week. Change the medium every two days until the monocytes differentiate and proliferates efficiently to become confluent.Now, rinse the differentiated macrophages in the flask three times with 10 milliliters of 37 degrees Celsius DPBS without calcium and magnesium. Subsequently, add 10 milliliters of 37 degrees Celsius 0.25%Trypson EDTA solution. Next, place the flask in a cell culture incubator for 10 to 15 minutes.Following this, approximately 90%of the macrophages should have rounded and detached. Then, add 10 milliliters of RPMI 1640 medium containing 10%FBS to stop trypsinization. If necessary, use a cell lifter to completely remove the cells.Sometimes in this procedure many macrophages remain attached. These macrophages can be removed following trypsinization by passing a cell lifter across the flask surface. Afterward, transfer the macrophage cell suspension from the flask into a 15 milliliter polypropylene tube.Centrifuge it for five minutes at room temperature and discard the supernatant. Then gently simply re-suspend the macrophages in one milliliter of complete medium. Based on the cell count, add additional complete medium to achieve the desired seeding cell density.Then, plate the macrophages in 1.5 milliliters of medium per well of a 12 well plate. One times 10 to the fifth cells in 1.5 milliliters of medium per well, usually produces a near confluent culture. Following seeding, incubate the macrophages overnight at 37 degrees Celsius to allow cell attachment before using them in experiments.This figure shows the face contrast microscopic images of cryopreserved fresh monocytes during their MCSF induced differentiation into macrophages at low magnification. The images of monocytes were taken on day three and seven of culture in flask, and on day eight, one day after their harvesting and re-plating in the 12 well culture plate. Shown here is the comparison of fresh versus cryopreserved monocytes used to produced macrophages at high magnification.The phase loosened vacuoles are macropinosomes. After watching this video you should have a good understanding of how to cryopreserve and later differentiate human monocytes with MCSF into macrophages. Subsequently, the macrophages can be cultured at desired cell densities for experiments.

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Research

JoVE Journal

Immunology and Infection

Investigation of Macrophage Polarization Using Bone Marrow Derived Macrophages

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic stem/progenitor cells from the bone marrow are directed into monocytic differentiation, followed by M1 or M2 stimulation. The activation status can be tracked by changes in cell surface antigens, gene expression and cell signaling pathways.

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic stem/progenitor cells from the bone marrow are directed into monocytic differentiation, followed by M1 or M2 stimulation. The activation status can be tracked by changes in cell surface antigens, gene expression and cell signaling pathways.

The article describes a readily easy adaptive in vitro model to investigate macrophage polarization. In the presence of GM-CSF/M-CSF, hematopoietic ...

Activation and Measurement of NLRP3 Inflammasome Activity Using IL-1&#946; in Human Monocyte-derived Dendritic Cells

Inflammatory processes resulting from the secretion of Interleukin (IL)-1 family cytokines by immune cells lead to local or systemic inflammation, tissue remodeling and repair, and virologic control1,2 . Interleukin-1&#946; is an essential element of the innate immune response and contributes to eliminate invading pathogens while preventing the establishment of persistent infection1-5.
Inflammasomes are the key signaling platform for the activation of interleukin 1 converting enzyme (ICE or Caspase-1). The NLRP3 inflammasome requires at least two signals in DCs to cause IL-1&#946; secretion6. Pro-IL-1&#946; protein expression is limited in resting cells; therefore a priming signal is required for IL-1&#946; transcription and protein expression. A second signal sensed by NLRP3 results in the formation of the multi-protein NLRP3 inflammasome. The ability of dendritic cells to respond to the signals required for IL-1&#946; secretion can be tested using a synthetic purine, R848, which is sensed by TLR8 in human monocyte derived dendritic cells&#160;(moDCs) to prime cells, followed by activation of the NLRP3 inflammasome with the bacterial toxin and potassium ionophore, nigericin.
Monocyte derived DCs&#160;are easily produced in culture and provide significantly more cells than purified human myeloid DCs. The method presented here differs from other inflammasome assays in that it uses in vitro human, instead of mouse derived, DCs thus allowing for the study of the inflammasome in human disease and infection.

Dendritic cells (DCs)&#160;secrete IL-1&#946; in response to TLR8 recognition of synthetic purine, R848, followed by NLRP3 inflammasome activation with nigericin, therefore, IL-1&#946; can be used to measure NLRP3 inflammasome activity. Intracellular cytokine staining, immunoblotting, and ELISA are used to accurately measure NLRP3 inflammasome priming and activation via IL-1&#946; expression.

Inflammatory processes resulting from the secretion of Interleukin (IL)-1 family cytokines by immune cells lead to local or systemic inflammation, tissue ...

Generation of Human Monocyte-derived Dendritic Cells from Whole Blood

Dendritic cells (DCs) recognize foreign structures of different pathogens, such as viruses, bacteria, and fungi, via a variety of pattern recognition receptors (PRRs) expressed on their cell surface and thereby activate and regulate immunity. 
The major function of DCs is the induction of adaptive immunity in the lymph nodes by presenting antigens via MHC I and MHC II molecules to na&#239;ve T lymphocytes. Therefore, DCs have to migrate from the periphery to the lymph nodes after the recognition of pathogens at the sites of infection. For in vitro experiments or DC vaccination strategies, monocyte-derived DCs are routinely used. These cells show similarities in physiology, morphology, and function to conventional myeloid dendritic cells. They are generated by interleukin 4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulation of monocytes isolated from healthy donors. Here, we demonstrate how monocytes are isolated and stimulated from anti-coagulated human blood after peripheral blood mononuclear cell (PBMC) enrichment by density gradient centrifugation. Human monocytes are differentiated into immature DCs and are ready for experimental procedures in a non-clinical setting after 5 days of incubation.

Here, we demonstrate how monocytes are isolated by magnetic bead separation from peripheral blood mononuclear cells after density gradient centrifugation of human anti-coagulated blood. Following incubation for 5 days, human monocytes are differentiated into immature dendritic cells and are ready for experimental procedures in a non-clinical setting.

Dendritic cells (DCs) recognize foreign structures of different pathogens, such as viruses, bacteria, and fungi, via a variety of pattern recognition ...

Analysis of Microglia and Monocyte-derived Macrophages from the Central Nervous System by Flow Cytometry

Numerous studies have demonstrated the role of immune cells, in particular macrophages, in central nervous system (CNS) pathologies. There are two main macrophage populations in the CNS: (i) the microglia, which are the resident macrophages of the CNS and are derived from yolk sac progenitors during embryogenesis, and (ii) the monocyte-derived macrophages (MDM), which can infiltrate the CNS during disease and are derived from bone marrow progenitors. The roles of each macrophage subpopulation differ depending on the pathology being studied. Furthermore, there is no consensus on the histological markers or the distinguishing criteria used for these macrophage subpopulations. However, the analysis of the expression profiles of the CD11b and CD45 markers by flow cytometry allows us to distinguish the microglia (CD11b+CD45med) from the MDM (CD11b+CD45high). In this protocol, we show that the density gradient centrifugation and the flow cytometry analysis can be used to characterize these CNS macrophage subpopulations, and to study several markers of interest expressed by these cells as we recently published. Thus, this technique can further our understanding of the role of macrophages in mouse models of neurological diseases and can also be used to evaluate drug effects on these cells.

This protocol provides an analysis of the macrophage subpopulations in the adult mouse central nervous system by flow cytometry and is helpful for the study of multiple markers expressed by these cells.

Numerous studies have demonstrated the role of immune cells, in particular macrophages, in central nervous system (CNS) pathologies. There are two main ...

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and their important role in lung development and function, as well as their lung-localized responses to infection and inflammation. To date, no unified method for identification, isolation, and handling of alveolar macrophages from humans and mice exists. Such a method is needed for studies on these important innate immune cells in various experimental settings. The method described here, which can be easily adopted by any laboratory, is a simplified approach to harvesting alveolar macrophages from bronchoalveolar lavage fluid or from lung tissue and maintaining them in vitro. Because alveolar macrophages primarily occur as adherent cells in the alveoli, the focus of this method is on dislodging them prior to harvest and identification. The lung is a highly vascularized organ, and various cell types of myeloid and lymphoid origin inhabit, interact, and are influenced by the lung microenvironment. By using the set of surface markers described here, researchers can easily and unambiguously distinguish alveolar macrophages from other leukocytes, and purify them for downstream applications. The culture method developed herein supports both human and mouse alveolar macrophages for in vitro growth, and is compatible with cellular and molecular studies.

Isolation and In Vitro Culture of Murine and Human Alveolar Macrophages

This communication describes methodologies for isolation and culture of alveolar macrophages from humans and murine models for experimental purposes.

Alveolar macrophages are terminally differentiated, lung-resident macrophages of prenatal origin. Alveolar macrophages are unique in their long life and ...

In Vitro Differentiation of Mouse Granulocyte-macrophage-colony-stimulating Factor (GM-CSF)-producing T Helper (THGM) Cells

The granulocyte-macrophage-colony-stimulating factor (GM-CSF)-producing T helper (THGM) cell is a newly identified T helper cell subset that predominantly secretes GM-CSF without producing interferon (IFN)&#947; or interleukin (IL)-17 and is found to play an essential role in the autoimmune neuroinflammation. A method of isolation of naive CD4+ T cells from a single-cell suspension of splenocytes and THGM cell generation from naive CD4+ T cells would be a useful technique in the study of T cell-mediated immunity and autoimmune diseases. Here we describe a method that differentiates mouse naive CD4+ T cells into THGM cells promoted by IL-7. The outcome of the differentiation was assessed by the analysis of the cytokines expression using different techniques, including intracellular cytokine staining combined with flow cytometry, a quantitative real-time polymerase chain reaction (PCR), and enzyme-linked immunosorbent assays (ELISA). Using the THGM differentiation protocol as described here, about 55% of the cells expressed GM-CSF with a minimal expression of IFN&#945; or IL-17. The predominant expression of GM-CSF by THGM cells was further confirmed by the analysis of the expression of GM-CSF, IFN&#945;, and IL-17 at both mRNA and protein levels. Thus, this method can be used to differentiate naive CD4+ T cells to THGM cells in vitro, which will be useful in the study of THGM cell biology.

In Vitro Differentiation of Mouse Granulocyte-macrophage-colony-stimulating Factor GM-CSF-producing T Helper THGM Cells

Here, we present a protocol to differentiate murine granulocyte-macrophage-colony-stimulating-factor-producing T helper (THGM) cells from naive CD4+ T cells, including isolation of naive CD4+ T cells, differentiation of THGM, and analysis of differentiated THGM cells. This method can be applied to studies of the regulation and function of THGM cells.

The granulocyte-macrophage-colony-stimulating factor (GM-CSF)-producing T helper (THGM) cell is a newly identified T helper cell subset that predominantly ...

Quantification of Monocyte Chemotactic Activity In Vivo and Characterization of Blood Monocyte Derived Macrophages

Tissue homeostasis and repair are critically dependent on the recruitment of monocyte-derived macrophages. Both under- and over-recruitment of monocyte-derived macrophages can impair wound healing. We showed that high fat and high sugar diets promote monocyte priming and dysfunction, converting healthy blood monocytes into a hyper chemotactic phenotype poised to differentiate into macrophages with dysregulated activation profiles and impaired phenotypic plasticity. The over-recruitment of monocyte-derived macrophages and recruitment of macrophages with dysregulated activation profiles is believed to be a major contributor to the development of chronic inflammatory diseases associated with metabolic disorders, including atherosclerosis and obesity. The goal of this protocol is to quantify the chemotactic activity of blood monocytes as a biomarker for monocyte priming and dysfunction and to characterize the macrophage phenotype blood monocytes are poised to differentiate into in these mouse models. Using single cell Western blot analysis, we show that after 24 h 33%of cells recruited into MCP-1-loaded basement membrane-derived gel plugs injected into mice are monocytes and macrophages; 58% after day 3. However, on day 5, monocyte and macrophage numbers were significantly decreased. Finally, we show that this assays also allows for the isolation of live macrophages from the surgically retrieved basement membrane-derived gel plugs, which can then be subjected to subsequent characterization by single cell Western blot analysis.

Here we present a protocol to quantify the chemotactic activity of blood monocytes in mouse models, to assess the effects of nutritional, pharmacological and genetic interventions on blood monocyte and to characterize the blood monocytes derived macrophages in mouse models using monocyte-chemoattractant protein-1 (MCP-1)-loaded basement membrane-derived gel plugs.

Tissue homeostasis and repair are critically dependent on the recruitment of monocyte-derived macrophages. Both under- and over-recruitment of ...

In Vitro Stimulation and Visualization of Extracellular Trap Release in Differentiated Human Monocyte-derived Macrophages

The release of extracellular traps (ETs) by neutrophils has been identified as a contributing factor to the development of diseases related to chronic inflammation. Neutrophil ETs (NETs) consist of a mesh of DNA, histone proteins, and various granule proteins (i.e., myeloperoxidase, elastase, and cathepsin G). Other immune cells, including macrophages, can also produce ETs; however, to what extent this occurs in vivo and whether macrophage extracellular traps (METs) play a role in pathological mechanisms has not been examined in detail. To better understand the role of METs in inflammatory pathologies, a protocol was developed for visualizing MET release from primary human macrophages in vitro, which can also be exploited in immunofluorescence experiments. This allows further characterization of these structures and their comparison to ETs released from neutrophils. Human monocyte-derived macrophages (HMDM) produce METs upon exposure to different inflammatory stimuli following differentiation to the M1 pro-inflammatory phenotype. The release of METs can be visualized by microscopy using a green fluorescent nucleic acid stain that is impermeant to live cells (e.g., SYTOX green). Use of freshly isolated primary macrophages, such as HMDM, is advantageous in modeling in vivo inflammatory events that are relevant to potential clinical applications. This protocol can also be used to study MET release from human monocyte cell lines (e.g., THP-1) following differentiation into macrophages with phorbol myristate acetate or other macrophage cell lines (e.g., the murine macrophage-like J774A.1 cells).

Presented here is a protocol to detect macrophage extracellular trap (MET) production in live cell culture using microscopy and fluorescence staining. This protocol can be further extended to examine specific MET protein markers by immunofluorescence staining.

The release of extracellular traps (ETs) by neutrophils has been identified as a contributing factor to the development of diseases related to chronic ...

Isolation and In vitro Culture of Bone Marrow-Derived Macrophages for the Study of NO-Redox Biology

Macrophages are derived from hematopoietic progenitor cells throughout the body, are central to inflammatory processes, and participate in innate and adaptive immune responses. In vitro study of macrophages can be undertaken by ex vivo culture from the peritoneum or through differentiation of myeloid bone marrow progenitor cells to form bone marrow-derived macrophages (BMDMs). A common approach to macrophage differentiation from precursors involves the use of conditioned media from L929 cells (LCM). This media is easy to self-produce but suffers from batch variability, and its constituents are undefined. Similarly, Foetal Bovine Serum (FBS) is used to support growth but contains a vast mixture of undefined molecules that may vary between batches. These methods are not adequate for the study of nitric oxide biology and redox mechanisms as they both contain substantial amounts of small molecules that either interfere with redox mechanisms or supplement levels of cofactors, such as tetrahydrobiopterin (BH4), required for the production of NO from inducible nitric oxide synthase (iNOS). In this report, we present an optimized protocol allowing for control of the NO-redox environment by reducing the levels of exogenous biopterin while maintaining conditions suitable for cell growth and differentiation. Tight control of culture media composition helps ensure experimental reproducibility and facilitates accurate interpretation of results. In this protocol, BMDMs were obtained from a GTP cyclohydrolase (GCH)- deficient mouse model. Culture of BMDMs was performed with media containing either (i) conditioned LCM, or (ii) recombinant M-CSF and GM-CSF to produce minimal artifacts while obtaining BH4 and NO-deficient culture conditions - thus allowing for the reproducible study of NO-redox biology and immunometabolism in vitro.

Isolation and In vitro Culture of Bone Marrow-Derived Macrophages for the Study of NO-Redox Biology

This protocol has been established to culture tetrahydrobiopterin (BH4)- and inducible nitric oxide synthase (iNOS)-deficient primary murine macrophages to study NO-redox biology. The study focuses on reducing potential contamination of BH4 and other artifacts found in traditional isolation and culture methods which may confound experimental outcomes and interpretation of results.

Macrophages are derived from hematopoietic progenitor cells throughout the body, are central to inflammatory processes, and participate in innate and ...

Visualization of Inflammatory Caspases Induced Proximity in Human Monocyte-Derived Macrophages

Inflammatory caspases include caspase-1, -4, -5, -11, and -12 and belong to the subgroup of initiator caspases. Caspase-1 is required to ensure correct regulation of inflammatory signaling and is activated by proximity-induced dimerization following recruitment to inflammasomes. Caspase-1 is abundant in the monocytic cell lineage and induces maturation of the pro-inflammatory cytokines interleukin (IL)-1&#946; and IL-18 to active secreted molecules. The other inflammatory caspases, caspase-4 and -5 (and their murine homolog caspase-11) promote IL-1&#946; release by inducing pyroptosis. Caspase Bimolecular Fluorescence Complementation (BiFC) is a tool used to measure inflammatory caspase induced proximity as a readout of caspase activation. The caspase-1, -4, or -5 prodomain, which contains the region that binds to the inflammasome, is fused to non-fluorescent fragments of the yellow fluorescent protein Venus (Venus-N [VN] or Venus-C [VC]) that associate to reform the fluorescent Venus complex when the caspases undergo induced proximity. This protocol describes how to introduce these reporters into primary human monocyte-derived macrophages (MDM) using nucleofection, treat the cells to induce inflammatory caspase activation, and measure caspase activation using fluorescence and confocal microscopy. The advantage of this approach is that it can be used to identify the components, requirements, and localization of the inflammatory caspase activation complex in living cells. However, careful controls need to be considered to avoid compromising cell viability and behavior. This technique is a powerful tool for the analysis of dynamic caspase interactions at the inflammasome level as well as for the interrogation of the inflammatory signaling cascades in living MDM and monocytes derived from human blood samples.

This protocol describes the workflow to obtain monocytes-derived macrophages (MDM) from human blood samples, a simple method to efficiently introduce inflammatory caspase Bimolecular Fluorescence Complementation (BiFC) reporters into human MDM without compromising cell viability and behavior, and an imaging-based approach to measure inflammatory caspase activation in living cells.

Inflammatory caspases include caspase-1, -4, -5, -11, and -12 and belong to the subgroup of initiator caspases. Caspase-1 is required to ensure correct ...