Name: quantification of monocyte transmigration and foam cell formation from individuals with chronic inflammatory conditions
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The authors gratefully acknowledge the work of Prof. William Muller and Dr. Clare Westhorpe for their key role in development of earlier iterations of this model. The authors would also like to thank the AMREP Flow Cytometry core for the sorting of monocyte subsets and the Alfred Hospital Infectious Disease Unit clinical research nurses for the recruitment of HIV+ individuals for some studies. The authors gratefully acknowledge the contribution to this work of the Victoria Operational Infrastructure Support Program received by the Burnet Institute. TAA is supported by an RMIT University Vice-Chancellor&#39;s Postdoctoral Fellowship. This work was supported by NHMRC project grant 1108792 awarded to AJ and AH. TK is supported by NIH grants NIH K08AI08272, NIH/NCATS Grant # UL1TR000124.

NOTE: All experiments using human biological samples were performed with ethics approval from the Alfred Hospital Human Ethics Committee, Melbourne. All experiments were performed in Class II Biosafety cabinets unless specified. &#34;Prewarmed&#34; refers to reagents warmed to 37 &#176;C in a waterbath.
1. Preparation of Type I Fibrous Collagen Gels: Day 1
<ol>
	<li>Prepare polymerized collagen gels by sequentially adding and mixing 35.7 mM NaOH, 0.71 x M199, 4.58 mM acetic acid and 1.71 mg/...

<ol>
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J., Geissmann, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monocytes+in+atherosclerosis:+subsets+and+functions.">Monocytes in atherosclerosis: subsets and functions.</a> Nat Rev Cardiol. 7 (2), 77-86 (2010).</li><li>Xu, L., 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=Foamy+Monocytes+Form+Early+and+Contribute+to+Nascent+Atherosclerosis+in+Mice+With+Hypercholesterolemia.">Foamy Monocytes Form Early and Contribute to Nascent Atherosclerosis in Mice With Hypercholesterolemia.</a> Arterioscler Thromb Vasc Biol. 35 (8), 1787-1797 (2015).</li><li>Jackson, W. D., Weinrich, T. W., Woollard, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Very-low+and+low-density+lipoproteins+induce+neutral+lipid+accumulation+and+impair+migration+in+monocyte+subsets.">Very-low and low-density lipoproteins induce neutral lipid accumulation and impair migration in monocyte subsets.</a> Scientific Reports. 6, 20038 (2016).</li><li>Angelovich, T. A., Hearps, A. C., Jaworowski, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inflammation-induced+foam+cell+formation+in+chronic+inflammatory+disease.">Inflammation-induced foam cell formation in chronic inflammatory disease.</a> Immunol. Cell. Biol. 93 (8), 683-693 (2015).</li><li>Llodr&#225;, 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=Emigration+of+monocyte-derived+cells+from+atherosclerotic+lesions+characterizes+regressive,+but+not+progressive,+plaques.">Emigration of monocyte-derived cells from atherosclerotic lesions characterizes regressive, but not progressive, plaques.</a> Proc. Natl. Acad. Sci. 101 (32), 11779-11784 (2004).</li><li>Getz, G. S., Reardon, C. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+Models+of+Atherosclerosis.">Animal Models of Atherosclerosis.</a> Arterioscler. Thromb. Vasc. Biol. 32 (5), 1104-1115 (2012).</li><li>Meir, K. S., Leitersdorf, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atherosclerosis+in+the+Apolipoprotein+E-Deficient+Mouse.+A+Decade+of+Progress.">Atherosclerosis in the Apolipoprotein E-Deficient Mouse. A Decade of Progress.</a> Arterioscler. Thromb. Vasc. Biol. 24 (6), 1006-1014 (2004).</li><li>Hilgendorf, I., Swirski, F. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Making+a+difference:+Monocyte+Heterogeneity+in+Cardiovascular+Disease.">Making a difference: Monocyte Heterogeneity in Cardiovascular Disease.</a> Curr. Atheroscler. Rep. 14 (5), 450-459 (2012).</li><li>Rogacev, 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=Lower+Apo+A-I+and+Lower+HDL-C+Levels+Are+Associated+With+Higher+Intermediate+CD14++CD16++Monocyte+Counts+That+Predict+Cardiovascular+Events+in+Chronic+Kidney+Disease.">Lower Apo A-I and Lower HDL-C Levels Are Associated With Higher Intermediate CD14++CD16+ Monocyte Counts That Predict Cardiovascular Events in Chronic Kidney Disease.</a> Arterioscler. Thromb. Vasc. Biol. 34 (9), 2120-2127 (2014).</li><li>Rogacev, 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=CD14++CD16++Monocytes+Independently+Predict+Cardiovascular+Events:+A+Cohort+Study+of+951+Patients+Referred+for+Elective+Coronary+Angiography.">CD14++CD16+ Monocytes Independently Predict Cardiovascular Events: A Cohort Study of 951 Patients Referred for Elective Coronary Angiography.</a> J. Am. Coll. Cardiol. 60 (16), 1512-1520 (2012).</li><li>Justus, C. R., Leffler, N., Ruiz-Echevarria, M., Yang, L. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+Cell+Migration+and+Invasion+Assays.">In vitro Cell Migration and Invasion Assays.</a> J. Vis. Exp. (88), e51046 (2014).</li><li>Boyden, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Chemotactic+Effect+Of+Mixtures+Of+Antibody+And+Antigen+On+Polymorphonuclear+Leucocytes.">The Chemotactic Effect Of Mixtures Of Antibody And Antigen On Polymorphonuclear Leucocytes.</a> J. Exp. Med. 115 (3), 453-466 (1962).</li><li>Westhorpe, C. L. V., 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=Endothelial+cell+activation+promotes+foam+cell+formation+by+monocytes+following+transendothelial+migration+in+an+in+vitro+model.">Endothelial cell activation promotes foam cell formation by monocytes following transendothelial migration in an in vitro model.</a> Exp. Mol. Pathol. 93, 220-226 (2012).</li><li>Quinn, M. T., Parthasarathy, S., Fong, L. G., Steinberg, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxidatively+modified+low+density+lipoproteins:+a+potential+role+in+recruitment+and+retention+of+monocyte/macrophages+during+atherogenesis.">Oxidatively modified low density lipoproteins: a potential role in recruitment and retention of monocyte/macrophages during atherogenesis.</a> Proc. Natl. Acad. Sci. 84 (9), 2995-2998 (1987).</li><li>Henriksen, T., Mahoney, E. M., Steinberg, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+macrophage+degradation+of+biologically+modified+low+density+lipoprotein.">Enhanced macrophage degradation of biologically modified low density lipoprotein.</a> Arterioscler. Thromb. Vasc. Biol. 3 (2), 149-159 (1983).</li><li>Parthasarathy, S., Raghavamenon, A., Garelnabi, M. O., Santanam, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxidized+Low-Density+Lipoprotein.">Oxidized Low-Density Lipoprotein.</a> Methods Mol. Biol. 610, 403-417 (2010).</li><li>Muller, W. A., Weigl, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monocyte-selective+transendothelial+migration:+dissection+of+the+binding+and+transmigration+phases+by+an+in+vitro+assay.">Monocyte-selective transendothelial migration: dissection of the binding and transmigration phases by an in vitro assay.</a> J. Exp. Med. 176 (3), 819-828 (1992).</li><li>Maisa, A., 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=Monocytes+from+HIV-infected+individuals+show+impaired+cholesterol+efflux+and+increased+foam+cell+formation+after+transendothelial+migration.">Monocytes from HIV-infected individuals show impaired cholesterol efflux and increased foam cell formation after transendothelial migration.</a> AIDS. 29 (12), 1445-1457 (2015).</li><li>Angelovich, T. A., 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=Ex+vivo+foam+cell+formation+is+enhanced+in+monocytes+from+older+individuals+by+both+extrinsic+and+intrinsic+mechanisms.">Ex vivo foam cell formation is enhanced in monocytes from older individuals by both extrinsic and intrinsic mechanisms.</a> Exp. Gerontol. 80, 17-26 (2016).</li><li>Westhorpe, C. L. V., 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=Effects+of+HIV-1+infection+in+vitro+on+transendothelial+migration+by+monocytes+and+monocyte-derived+macrophages.">Effects of HIV-1 infection in vitro on transendothelial migration by monocytes and monocyte-derived macrophages.</a> J. Leukoc. Biol. 85 (6), 1027-1035 (2009).</li><li>Furie, M. B., Cramer, E. B., Naprstek, B. L., Silverstein, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cultured+endothelial+cell+monolayers+that+restrict+the+transendothelial+passage+of+macromolecules+and+electrical+current.">Cultured endothelial cell monolayers that restrict the transendothelial passage of macromolecules and electrical current.</a> J. Cell Biol. 98 (3), 1033-1041 (1984).</li><li>M&#252;ller, A. M., 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=Expression+of+the+Endothelial+Markers+PECAM-1,+vWf,+and+CD34+in+Vivo+and+in+Vitro.">Expression of the Endothelial Markers PECAM-1, vWf, and CD34 in Vivo and in Vitro.</a> Exp. Mol. Pathol. 72 (3), 221-229 (2002).</li><li>Kelesidis, T., 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=Predictors+of+impaired+HDL+function+in+HIV-1+infected+compared+to+uninfected+individuals.">Predictors of impaired HDL function in HIV-1 infected compared to uninfected individuals.</a> J. Acquir. Immune Defic. Syndr. , (2017).</li><li>Rogacev, 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=Monocyte+heterogeneity+in+obesity+and+subclinical+atherosclerosis.">Monocyte heterogeneity in obesity and subclinical atherosclerosis.</a> European Heart Journal. 31 (3), 369-376 (2010).</li><li>Gacka, M., 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=Proinflammatory+and+atherogenic+activity+of+monocytes+in+Type+2+diabetes.">Proinflammatory and atherogenic activity of monocytes in Type 2 diabetes.</a> J. Diabetes Complications. 24 (1), 1-8 (2010).</li><li>Rogacev, K. 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The protocol described here offers a versatile and physiologically relevant method for assessing the atherogenicity of monocytes from human clinical cohorts, by combining both monocyte transmigration and foam cell formation. This model offers advantages over alternative methods of foam cell formation as it takes into account the effect of monocyte transmigration on foam cell formation and allows the measurement of reverse transmigration6 in addition to the inherent propensity of monocytes to matur...

Monocyte transmigration is a crucial step in the development of atherosclerotic plaque that may lead to thrombosis, stroke and myocardial infarction. Atherosclerotic plaques develop from fatty streaks, generally present at sites of low oscillatory blood flow in medium to large arteries, where deposited lipid contributes to endothelial activation and localized inflammation1. Monocytes are recruited to endothelial cells in fatty streaks via monocyte chemotactic proteins (such as CCL2) and transmigrate into the intima2. Following transmigration, monocytes may form atherogenic, lipid-laden macrophages called foam cells as a consequence of lipid uptake, lipid synthesis, down-regulation of cholesterol efflux or a combination of the above factors. Monocytes may also accumulate lipids in the circulation and have a &#39;foamy&#39; phenotype, possibly predisposing cells for foam cell formation3,4. Foam cells are the defining feature of fatty streaks and early-stage atherosclerotic plaques and their formation is influenced by both lipid and inflammatory mediators5. Alternatively, monocytes have the ability to reverse transmigrate from the artery into the bloodstream6, thereby removing lipid from the intima and acting to maintain the health of the artery.
Determining the propensity of monocytes to transmigrate across arterial endothelium and form foam cells in the intima, or to reverse transmigrate and carry lipid out of the plaque, is a key requirement for understanding the role of monocyte activation in increasing atherosclerotic risk. Mouse models of CADs such as atherosclerosis are important in elucidating real-time in vivo information on fatty streak/atherosclerotic plaque development. However, these models require a genetic alteration of the natural cholesterol processing abilities of these animals usually coupled with drastic alterations in diet (such as the ApoE-/- Western-type diet model)7,8, thereby, inducing non-physiological accumulation of circulating lipid levels which drive plaque development. These models may have limited relevance to chronic inflammatory human conditions such as HIV infection which are not associated with increased circulating cholesterol or low-density lipoprotein (LDL) levels. Furthermore, differences in monocyte biology between humans and mice make the testing of immunological questions regarding the relevance of subpopulations of monocytes (such as intermediate monocytes (CD14++CD16+))9 difficult. This is important when studying the mechanisms driving cardiovascular disease as intermediate monocyte counts independently predict cardiovascular events10,11. While assays exist to sequentially measure either monocyte transmigration or foam cell formation in isolation, no in vitro assay has been validated for quantifying both aspects of early atherogenesis using the same cells from clinical cohorts. Transwell models utilize a modified Boyden two-chamber system whereby cells are loaded into the top chamber and transmigrate across a porous plastic barrier or cell monolayer into a lower chamber that typically contains media with chemoattractant12,13. Whilst widely used for analyzing leukocyte transmigration, these models do not generally incorporate a layer representing the intima, resulting in transmigrated cells migrating into solution, and do not allow for the measurement of foam cell formation or reverse transmigration of the same cells. Conversely, models of foam cell formation do not account for any transmigratory-induced changes to monocytes or effects of endothelial activation which is known to contribute to foam cell formation14. Furthermore, these systems induce foam cell formation from macrophages adhered to cell culture plates by the addition of saturating concentrations of exogenous oxidized low-density lipoprotein (oxLDL)15,16, a key inducer of foam cell formation. LDL used in these models is often oxidized by non-physiologically-relevant processes such as CuSO4 treatment17, therefore, questioning the physiological importance of studies using these models.
Here we describe an assay that quantifies monocyte transmigration and foam cell formation of the same cells which does not require the addition of exogenous oxLDL, thus better modelling the role of monocytes in foam cell formation. This model was originally developed by Professor William Muller (Northwestern University, Chicago)18, and has been further refined in our laboratory to assess ex vivo the atherogenicity of monocytes isolated under non-activating conditions from individuals with underlying inflammatory conditions accompanying diseases such as HIV infection19 as well as ageing20, that are associated with an increased risk of atherosclerosis. This model also provides a platform for answering basic biological questions regarding the propensity of different monocyte subsets to form foam cells20, the influence of endothelial activation by cytokines such as TNF on foam cell formation14, and the migratory properties of monocytes such as the depth and speed of transmigration in gels19. Furthermore, monocyte transmigration and foam cell formation can be quantified using standard microscopy, live cell imaging, flow cytometry and imaging flow cytometry, therefore, providing a versatile method to evaluate the role of monocytes in atherogenesis.

<table border="0" cellpadding="0" cellspacing="0" width="1187">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Gel preparation reagents</td>
			<td style="width:128px;"></td>
			<td style="width:111px;"></td>
			<td style="width:595px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">NaOH</td>
			<td>Sigma-Aldrich</td>
			<td>221465-500G</td>
			<td>0.1 M NaOH diluted in H20</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">10X M199</td>
			<td>Sigma-Aldrich</td>
			<td style="width:111px;">M0650</td>
			<td style="width:595px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">AcCOOH</td>
			<td>Sigma-Aldrich</td>
			<td>695092-100ML</td>
			<td>20 mM Acetic acid diluted in H20</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cultrex Bovine Collagen I</td>
			<td>R&#38;D Systems</td>
			<td>3442-050-01</td>
			<td>Type I Fibrous Collagen</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Name</td>
			<td style="width:128px;">Company</td>
			<td style="width:111px;">Catalog Number</td>
			<td style="width:595px;">Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cell culture</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">M199</td>
			<td>Life Technologies</td>
			<td>11150-059</td>
			<td style="width:595px;">M199 media containing Earle&#39;s salts, L-glutamine and 2.2 g/L Sodium Bicarbonate. 
			Media supplemented with 100 &#181;g/mL L-glutamine&#160; and 100 U/mL penicillin/streptomycin&#160;</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">M20</td>
			<td></td>
			<td></td>
			<td style="width:595px;">Supplemented M199 containing 20% heat-inactivated pooled or donor serum. 
			Individual lipid species such as LDL can be added to M199.</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;">HUVEC</td>
			<td></td>
			<td></td>
			<td style="width:595px;">Primary human umbilical cord endothelial cells (HUVEC) can be isolated from umbilical cords donated with informed consent and ethics approval. Isolated HUVEC may also be purchased commercially.</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Human coronary artery endothelial cells</td>
			<td></td>
			<td></td>
			<td style="width:595px;">Primary human coronary artery endothelial cells can be isolated from arteries donated with informed consent and ethics approval. Isolated cells may also be purchased commercially.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">EDTA</td>
			<td>BDH Merck</td>
			<td>10093.5V</td>
			<td>Ethylenediaminetetraacetic acid (EDTA) - 0.5 M, pH 8.0</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">EGTA</td>
			<td>Sigma-Aldrich</td>
			<td>E3889-500G</td>
			<td>Ethylene glycol-bis(&#946;-aminoethyl ether)-N,N,N&#39;,N&#39;-tetraacetic acid (EGTA) - 1 mM, pH 8.0</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">0.05% trypsin EDTA</td>
			<td>Gibco</td>
			<td>25300-054</td>
			<td>0.05% trypsin/0.53 EDTA (1X)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">L-glutamine</td>
			<td>Gibco</td>
			<td>25030-081</td>
			<td>L-glutamine (200 mM)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Penicillin/streptomycin&#160;</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td>Penicillin/streptomycin (10,000 units/mL Penicillin and 10,000 &#181;g/mL Streptomycin)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">New born calf serum</td>
			<td style="width:128px;">Gibco</td>
			<td style="width:111px;">16010-142</td>
			<td style="width:595px;">New born calf serum: New Zealand origin</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Fibronectin</td>
			<td>Sigma-Aldrich</td>
			<td>F1056-1MG</td>
			<td>Fibronectin - 50 &#181;g/mL aliquots prepared and stored</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">PBS (1X)</td>
			<td>Gibco</td>
			<td>14200-075</td>
			<td>Dulbecco&#39;s Phosphate Buffered Saline (10X): Dilute to 1X with sterile H20</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">0.1% TNF</td>
			<td>Gibco</td>
			<td>PHC3015</td>
			<td>Recombinant human TNF - Reconstituted in H20 and stored in 10 &#181;g/mL aliquots</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Low-density lipoprotein</td>
			<td>Merck Millipore</td>
			<td>LP2-2MG</td>
			<td>Low-density lipoprotein (LDL)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Name</td>
			<td style="width:128px;">Company</td>
			<td style="width:111px;">Catalog Number</td>
			<td style="width:595px;">Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Microscopy</td>
			<td style="width:128px;"></td>
			<td style="width:111px;"></td>
			<td style="width:595px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">1 or 2% formaldehyde</td>
			<td>Polysciences</td>
			<td>4018</td>
			<td>1 or 2% formaldehyde diluted with sterile H20</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">50% and 78% methanol</td>
			<td>Ajax Finechem</td>
			<td>318-2.5L GL</td>
			<td>50% or 78% v/v methanol, diluted with H20</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Oil Red O stain</td>
			<td>Sigma-Aldrich</td>
			<td>O0625-25G</td>
			<td>Dilute to 2 mg/mL in 22% 1M NaOH and 78% (v/v) methanol</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Microscope slides</td>
			<td>Mikro-Glass</td>
			<td>S41104AMK</td>
			<td style="width:595px;">Twin frosted 45 degree ground edge microscope slides (25 X 76 mm)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cover slips</td>
			<td>Menzel-Gl&#228;ser</td>
			<td>MENCS224015GP</td>
			<td>22 x 40 mm #1.5 size glass cover slips</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Double-sided tape</td>
			<td>3M Scotch</td>
			<td>4011</td>
			<td>Super strength exterior mounting tape (25.4 mm x 1.51 m)</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;">Giemsa stain</td>
			<td>Merck Millipore</td>
			<td>1.09204.0500</td>
			<td>Giemsa&#39;s azur eosin methylene blue solution (dilute stock 1:10 in H20)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Hole punch</td>
			<td style="width:128px;"></td>
			<td style="width:111px;"></td>
			<td style="width:595px;">Hand-held single hole punch (6.35 mm punch)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Name</td>
			<td style="width:128px;">Company</td>
			<td style="width:111px;">Catalog Number</td>
			<td style="width:595px;">Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Flow cytometry</td>
			<td style="width:128px;"></td>
			<td style="width:111px;"></td>
			<td style="width:595px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Collagenase D</td>
			<td>Roche Diagnostics</td>
			<td>11088858001</td>
			<td>Collagenase D diluted in M199 media to 1 mg/mL&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">35 &#181;m nylon mesh capped polystyrene FACS tubes</td>
			<td>BD Biosciences</td>
			<td>352235</td>
			<td>35 &#181;m nylon mesh capped polystyrene FACS tubes</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Live/Dead Fixable Yellow Dead Cell stain</td>
			<td>Life Technologies</td>
			<td>L34959</td>
			<td>Live/Dead Fixable Yellow Dead Cell stain</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">FACS wash</td>
			<td></td>
			<td></td>
			<td>Prepare by mixing 1 X PBS-, 2 mM EDTA and 1% New born calf serum</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Name</td>
			<td style="width:128px;">Company</td>
			<td style="width:111px;">Catalog Number</td>
			<td style="width:595px;">Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:355px;">Plasticware</td>
			<td style="width:128px;"></td>
			<td style="width:111px;"></td>
			<td style="width:595px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">96 well plate</td>
			<td>Nunclon</td>
			<td>167008</td>
			<td>Delta surface flat-bottomed 96 well plate</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">10 cm Petri Dish</td>
			<td>TPP</td>
			<td>93100</td>
			<td>Sterile 10 cm Petri dish</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">1.5 mL Eppendorf tubes</td>
			<td>Eppendorf</td>
			<td>0030 125.150</td>
			<td>Eppendorf tubes</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Transfer pipette</td>
			<td>Samco Scientific</td>
			<td>222-20S</td>
			<td>Sterile transfer pipette (1 mL, large bulb)</td>
		</tr>
	</tbody>
</table>

quantification of monocyte transmigration and foam cell formation from individuals with chronic inflammatory conditions

Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Atherosclerosis, a leading cause of CAD, is initiated by the transmigration of innate immune monocytes to inflammatory sites of deposited lipid called fatty streaks, which are present in arterial walls of medium to large arteries. The key pathogenic feature of lesions at this early stage of atherosclerosis is the maturation of monocytes which migrate into arteries to form foam cells or lipid-laden macrophages. Considerable evidence supports the hypothesis that risk of atherosclerosis is increased by chronic inflammatory conditions accompanying diseases such as rheumatoid arthritis and HIV, as well as general ageing, and that this risk is predicted by monocyte activation. While mouse models provide a good platform to investigate the role of monocytes in atherogenesis in vivo, they require genetic alteration of natural cholesterol metabolism and drastic alteration of normal mouse diets, and have limited suitability for the study of atherogenic influences of human comorbid diseases. This motivated us to develop a human in vitro model to measure the atherogenic potential of monocytes isolated from individuals with defined disease states. Currently, human in vitro models are limiting in that they evaluate monocyte transmigration and foam cell formation in isolation. Here we describe a protocol in which monocytes isolated from patient blood transmigrate across human endothelial cells into a type 1 collagen matrix, and their propensity to mature into foam cells in the presence or absence of exogenous lipid is measured. The protocol has been validated for the use of human monocytes purified from individuals with HIV infection and elderly HIV uninfected individuals. This model is versatile and allows monocyte transmigration and foam cell formation to be evaluated using either microscopy or flow cytometry as well as allowing the assessment of atherogenic factors present in serum or plasma.

Quantifying monocyte transmigration
Monocytes are added to the model as described in Figure 1, and six gels are prepared for each condition. Monocytes for 6 gels per donor (i.e., 5.0 x 104 monocytes per gel 6 gels = 3.0 x 105 monocytes per donor) are resuspended to a final volume of 600 &#181;L of M199 media containing the required serum/isolated lipid...

Watch this Scientific Journal Video about Quantification of Monocyte Transmigration and Foam Cell Formation from Individuals with Chronic Inflammatory Conditions at JoVE.com

Quantification of Monocyte Transmigration and Foam Cell Formation from Individuals with Chronic Inflammatory Conditions

We describe a protocol to measure transmigration by monocytes across human endothelial monolayers and their subsequent maturation into foam cells. This provides a versatile method to assess the atherogenic properties of monocytes isolated from people with different disease conditions and to evaluate factors in blood which may enhance this propensity.

Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Atherosclerosis, a leading cause of CAD, is initiated by the ...

Research

JoVE Journal

Immunology and Infection

Isolation of Human Umbilical Vein Endothelial Cells and Their Use in the Study of Neutrophil Transmigration Under Flow Conditions

Neutrophils are the most abundant type of white blood cell. They form an essential part of the innate immune system1. During acute inflammation, ...

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae

Characterization of Inflammatory Responses During Intranasal Colonization with Streptococcus pneumoniae

Nasopharyngeal colonization by Streptococcus pneumoniae is a prerequisite to invasion to the lungs or bloodstream1. This organism is capable of colonizing ...

Real-time Imaging of Endothelial Cell-cell Junctions During Neutrophil Transmigration Under Physiological Flow

During inflammation, leukocytes leave the circulation and cross the endothelium to fight invading pathogens in underlying tissues. This process is known ...

Isolation of Exosomes from the Plasma of HIV-1 Positive Individuals

Exosomes are small vesicles ranging in size from 30 nm to 100 nm that are released both constitutively and upon stimulation from a variety of cell types. ...

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 ...

Induction of an Inflammatory Response in Primary Hepatocyte Cultures from Mice

The liver plays a decisive role in the regulation of systemic inflammation. In chronic kidney disease in particular, the liver reacts in response to the ...

Bronchoalveolar Lavage of Murine Lungs to Analyze Inflammatory Cell Infiltration

Bronchoalveolar Lavage (BAL) is an experimental procedure that is used to examine the cellular and acellular content of the lung lumen ex vivo to gain ...

An Efficient and Simple Method to Establish NK and T Cell Lines from Patients with Chronic Active Epstein-Barr Virus Infection

A number of methods have been described to establish NK/T cell lines from patients with lymphoma or lymphoproliferative syndrome. These methods employed ...

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 ...

Separation of Rat Epidermis and Dermis with Thermolysin to Detect Site-Specific Inflammatory mRNA and Protein

Easy-to-use and inexpensive techniques are needed to determine the site-specific production of inflammatory mediators and neurotrophins during skin ...