Umbilical cords were collected with the assistance of the Birmingham Women's Health Care NHS Trust. HMM was supported by an Arthritis Research UK Career Development Fellowship (19899) and Systems Science for Health, University of Birmingham (5212).

1. Isolation and Culture of Primary Human Endothelial Cells and Mesenchymal Stem Cells
<ol>
	<li>Isolation and culture of human umbilical vein endothelial cells (HUVEC):
	<ol>
		<li>Put umbilical cord on a tray with paper towels and spray with 70% ethanol. Place in a tissue culture hood. Identify the vein and cannulate at both ends. Place a cable tie around the cannulated end to secure it.</li>
		<li>Wash out venous blood with PBS using a syringe. Fill syringe with air and pass through the vein to remove and discard th...

<ol>
	<li>Springer, T. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traffic+signals+on+endothelium+for+lymphocyte+recirculation+and+leukocyte+emigration.">Traffic signals on endothelium for lymphocyte recirculation and leukocyte emigration.</a> Ann. Rev. Physiol. 57, 827-872 (1995).</li><li>Ley, K., Laudanna, C., Cybulsky, M. I., Nourshargh, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Getting+to+the+site+of+inflammation:+the+leukocyte+adhesion+cascade+updated.">Getting to the site of inflammation: the leukocyte adhesion cascade updated.</a> Nature reviews. Immunology. 7 (9), 678-689 (2007).</li><li>McGettrick, H. M., Butler, L. M., Buckley, C. D., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+stroma+as+a+regulator+of+leukocyte+recruitment+in+inflammation.">Tissue stroma as a regulator of leukocyte recruitment in inflammation.</a> Journal of leukocyte biology. 91 (3), 385-400 (2012).</li><li>Serhan, C. N., Savill, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Resolution+of+inflammation:+the+beginning+programs+the+end.">Resolution of inflammation: the beginning programs the end.</a> Nature immunology. 6 (12), 1191-1197 (2005).</li><li>Schmidt, S., Moser, M., Sperandio, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+molecular+basis+of+leukocyte+recruitment+and+its+deficiencies.">The molecular basis of leukocyte recruitment and its deficiencies.</a> Molecular immunology. 55, 49-58 (2013).</li><li>Luu, N. T., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+Ability+of+Exogenous+Chemotactic+Agents+to+Disrupt+Transendothelial+Migration+of+Flowing+Neutrophils.">Differential Ability of Exogenous Chemotactic Agents to Disrupt Transendothelial Migration of Flowing Neutrophils.</a> The Journal of Immunology. 164 (11), 5961-5969 (2000).</li><li>Smith, C. W., Rothlein, 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=Recognition+of+an+endothelial+determinant+for+CD+18-dependent+human+neutrophil+adherence+and+transendothelial+migration.">Recognition of an endothelial determinant for CD 18-dependent human neutrophil adherence and transendothelial migration.</a> The Journal of clinical investigation. 82 (5), 1745-1756 (1988).</li><li>Luscinskas, F. W., Brock, A. F., Arnaout, M. A., Gimbrone, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial-leukocyte+adhesion+molecule-1-dependent+and+leukocyte+(CD11/CD18)-dependent+mechanisms+contribute+to+polymorphonuclear+leukocyte+adhesion+to+cytokine-activated+human+vascular+endothelium.">Endothelial-leukocyte adhesion molecule-1-dependent and leukocyte (CD11/CD18)-dependent mechanisms contribute to polymorphonuclear leukocyte adhesion to cytokine-activated human vascular endothelium.</a> J. Immunol. 142 (7), (1989).</li><li>Bahra, P., Rainger, G. E., Wautier, J. L., Nguyet-Thin, L., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Each+step+during+transendothelial+migration+of+flowing+neutrophils+is+regulated+by+the+stimulatory+concentration+of+tumour+necrosis+factor-alpha.">Each step during transendothelial migration of flowing neutrophils is regulated by the stimulatory concentration of tumour necrosis factor-alpha.</a> Cell adhesion and communication. 6 (6), 491-501 (1998).</li><li>Piali, L., Weber, 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=The+chemokine+receptor+CXCR3+mediates+rapid+and+shear-resistant+adhesion-induction+of+effector+T+lymphocytes+by+the+chemokines+IP10+and+Mig.">The chemokine receptor CXCR3 mediates rapid and shear-resistant adhesion-induction of effector T lymphocytes by the chemokines IP10 and Mig.</a> European journal of immunology. 28 (3), 961-972 (1998).</li><li>McGettrick, H. M., Smith, E., 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=Fibroblasts+from+different+sites+may+promote+or+inhibit+recruitment+of+flowing+lymphocytes+by+endothelial+cells.">Fibroblasts from different sites may promote or inhibit recruitment of flowing lymphocytes by endothelial cells.</a> European journal of immunology. 39 (1), 113-125 (2009).</li><li>McGettrick, H. M., Hunter, K., Moss, P. a., Buckley, C. D., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+observations+of+the+kinetics+of+migrating+T+cells+suggest+active+retention+by+endothelial+cells+with+continual+bidirectional+migration.">Direct observations of the kinetics of migrating T cells suggest active retention by endothelial cells with continual bidirectional migration.</a> Journal of leukocyte biology. 85 (1), 98-107 (2009).</li><li>McGettrick, H. M., Buckley, C. D., Filer, A., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stromal+cells+differentially+regulate+neutrophil+and+lymphocyte+recruitment+through+the+endothelium.">Stromal cells differentially regulate neutrophil and lymphocyte recruitment through the endothelium.</a> Immunology. 131 (3), 357-370 (2010).</li><li>Tull, S. P., Yates, C. 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=Omega-3+Fatty+acids+and+inflammation:+novel+interactions+reveal+a+new+step+in+neutrophil+recruitment.">Omega-3 Fatty acids and inflammation: novel interactions reveal a new step in neutrophil recruitment.</a> PLoS biology. 7 (8), e1000177 (2009).</li><li>Ahmed, S. R., McGettrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prostaglandin+D2+regulates+CD4++memory+T+cell+trafficking+across+blood+vascular+endothelium+and+primes+these+cells+for+clearance+across+lymphatic+endothelium.">Prostaglandin D2 regulates CD4+ memory T cell trafficking across blood vascular endothelium and primes these cells for clearance across lymphatic endothelium.</a> Journal of immunology. 187 (3), 1432-1439 (2011).</li><li>Bradfield, P. F., Amft, N., 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=Rheumatoid+fibroblast-like+synoviocytes+overexpress+the+chemokine+stromal+cell-derived+factor+1+(CXCL12),+which+supports+distinct+patterns+and+rates+of+CD4++and+CD8++T+cell+migration+within+synovial+tissue.">Rheumatoid fibroblast-like synoviocytes overexpress the chemokine stromal cell-derived factor 1 (CXCL12), which supports distinct patterns and rates of CD4+ and CD8+ T cell migration within synovial tissue.</a> Arthritis and rheumatism. 48 (9), 2472-2482 (2003).</li><li>Filer, A., Parsonage, G., 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=Differential+survival+of+leukocyte+subsets+mediated+by+synovial,+bone+marrow,+and+skin+fibroblasts:+site-specific+versus+activation-dependent+survival+of+T+cells+and+neutrophils.">Differential survival of leukocyte subsets mediated by synovial, bone marrow, and skin fibroblasts: site-specific versus activation-dependent survival of T cells and neutrophils.</a> Arthritis and rheumatism. 54 (7), 2096-2108 (2006).</li><li>Lally, F., Smith, E., 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=A+novel+mechanism+of+neutrophil+recruitment+in+a+coculture+model+of+the+rheumatoid+synovium.">A novel mechanism of neutrophil recruitment in a coculture model of the rheumatoid synovium.</a> Arthritis and rheumatism. 52 (11), 3460-3490 (2005).</li><li>Chakravorty, S. J., McGettrick, H. M., Butler, L. M., Buckley, C. D., Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vitro.+model+for+analysing+neutrophil+migration+into+and+away+from+the+sub-endothelial+space:+Roles+of+flow+and+CD31.">An in vitro. model for analysing neutrophil migration into and away from the sub-endothelial space: Roles of flow and CD31.</a> Biorheology. 43 (1), 71-82 (2006).</li><li>Rainger, G. E., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cellular+Pathology+of+Atherosclerosis+Smooth+Muscle+Cells+Prime+Cocultured+Endothelial+Cells+for+Enhanced+Leukocyte+Adhesion.">Cellular Pathology of Atherosclerosis Smooth Muscle Cells Prime Cocultured Endothelial Cells for Enhanced Leukocyte Adhesion.</a> Circulation Research. 88 (6), 615-622 (2001).</li><li>Kuravi, S. J., McGettrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Podocytes+regulate+neutrophil+recruitment+by+glomerular+endothelial+cells+via+IL-6-mediated+crosstalk.">Podocytes regulate neutrophil recruitment by glomerular endothelial cells via IL-6-mediated crosstalk.</a> Journal of immunology. 193 (1), 234-243 (2004).</li><li>Parsonage, G., Filer, 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=A+stromal+address+code+defined+by+fibroblasts.">A stromal address code defined by fibroblasts.</a> Trends in immunology. 26 (3), 150-156 (2005).</li><li>Luu, N. T., McGettrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crosstalk+between+mesenchymal+stem+cells+and+endothelial+cells+leads+to+downregulation+of+cytokine-induced+leukocyte+recruitment.">Crosstalk between mesenchymal stem cells and endothelial cells leads to downregulation of cytokine-induced leukocyte recruitment.</a> Stem cells. 31 (12), 2690-2702 (2013).</li><li>Bevilacqua, M. P., Nelson, R. M., Mannori, G., Cecconi, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endothelial-leukocyte+adhesion+molecules+in+human+disease.">Endothelial-leukocyte adhesion molecules in human disease.</a> Annual review of medicine. 45, 361-378 (1994).</li><li>Stanness, K. A., Beatty, P. G., Ochs, H. D., Harlan, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+endothelial+cell+surface+factor(s)+induced+in+vitro.">An endothelial cell surface factor(s) induced in vitro.</a> 136 (12), 4548-4553 (1986).</li><li>Burton, V. J., Butler, L. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Delay+of+migrating+leukocytes+by+the+basement+membrane+deposited+by+endothelial+cells+in+long-term+culture.">Delay of migrating leukocytes by the basement membrane deposited by endothelial cells in long-term culture.</a> Experimental cell research. 317 (3), 276-292 (2011).</li><li>Luu, N. T., Rainger, G. E., Buckley, C. D., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CD31+Regulates+Direction+and+Rate+of+Neutrophil+Migration+over+and+under+Endothelial+Cells.">CD31 Regulates Direction and Rate of Neutrophil Migration over and under Endothelial Cells.</a> Journal of Vascular Research. 40 (5), 467-479 (2003).</li><li>McGettrick, H. M., Buckley, C. D., Ed Rainger, G., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Influence+of+stromal+cells+on+lymphocyte+adhesion+and+migration+on+endothelial+cells.">Influence of stromal cells on lymphocyte adhesion and migration on endothelial cells.</a> Methods in molecular biology. 616, 49-68 (2010).</li><li>Butler, L. M., McGettrick, H. M., Nash, G. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Static+and+dynamic+assays+of+cell+adhesion+relevant+to+the+vasculature.">Static and dynamic assays of cell adhesion relevant to the vasculature.</a> Methods in molecular biology. 467, 211-228 (2009).</li><li>Jeffery, H. C., Buckley, C. D., Moss, P., Rainger, G. E., Nash, G. B., McGettrick, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+effects+of+stromal+cells+on+the+migration+of+lymphocytes+into+and+through+inflamed+tissue+using+3-D+culture+models.">Analysis of the effects of stromal cells on the migration of lymphocytes into and through inflamed tissue using 3-D culture models.</a> Journal of immunological methods. 400-401, 45-57 (2013).</li></ol>

The authors declare that they have no conflicts of interest.

Here we describe two in vitro &#8220;vascular&#8221; models for studying the recruitment of circulating neutrophils by inflamed endothelium. A major advantage of these models is the ability to analyze each step in the leukocyte adhesion cascade in order, as would occur in vivo. We have previously observed a dose-dependent increase in neutrophil adhesion to and transmigration through TNF&#945;-stimulated EC9,29. We also describe how both models can be adapted to study the effects of stromal ce...

Inflammation is a protective response to microbial infection or tissue injury that requires tight regulation of leukocyte entry into and exit from the inflamed tissue to allow resolution1,2. Cross-talk between endothelial cells (EC) that line blood vessels, circulating leukocytes and tissue-resident stromal cells is essential for coordinating this process3. However, uncontrolled recruitment of leukocytes and their ineffective clearance underpin the development of chronic inflammatory diseases4. Our current understanding of leukocyte recruitment in health and disease is incomplete and more robust models are needed to analyze this process.
The mechanisms supporting the recruitment of leukocytes from blood through vascular EC in post-capillary venules have been well described1,2,5. Circulating leukocytes are captured by specialized receptors (e.g., VCAM-1, E-selectin, P-selectin) which are up-regulated on inflamed endothelium. These transient interactions allow leukocytes to interact with surface bound chemokines and lipid-derived mediators (either endothelial or stromal in origin) that activate integrins expressed by leukocytes6-11. This in turn stabilizes adhesion and drives migration across the endothelium and into the tissue12-15. Within tissue, recruited leukocytes are subjected to stromal-derived agents that influence their motility, function and survival16,17. Growing evidence strongly suggests that signals received at each stage of the recruitment process conditions leukocytes for the next. However, our understanding of leukocyte recruitment remains incomplete and very little is known about the components shaping leukocyte movement within tissue.
In Birmingham we have developed several in vitro &#8220;vascular&#8221; models to study the recruitment of leukocytes from flow9,18,19. We now understand that vascular EC act as immediate regulators of leukocyte recruitment responding to changes in their local microenvironment. Specifically, tissue-resident stromal cells can actively regulate the inflammatory response, in part by conversing with neighboring vascular EC to influence their role in recruitment3. We have previously shown that various stromal cells modulate the ability of EC to support adhesion and migration of leukocytes in a tissue-specific manner, and that these effects become altered in chronic diseases13,16,20,21. Thus, stromal cells establish tissue &#8216;address-codes&#8217; that define the context of each inflammatory response22. More recently, we have demonstrated that bone-marrow derived MSC (BMMSC) potently down-regulate the response of EC to cytokines, leading to a reduction in the recruitment of both neutrophils and lymphocytes23.
The mechanisms governing recruitment elucidated in vitro have largely used assays incorporating a single cell type (e.g., EC) or protein in isolation. However, these studies do not take into consideration the effects of the local tissue environment (i.e., the presence of stromal cells) on recruitment of leukocytes and their subsequent migration into the tissue. Here we describe two flow-based methods in which stromal cells, specifically mesenchymal stem cells (MSC), are co-cultured with EC23. Such models allow us to examine the effect of stromal cell on endothelial responses, in particular their ability to support leukocyte recruitment from flow.

<table border="0" cellpadding="0" cellspacing="0" >
	<tbody>
		<tr >
			<td >Collagenase Type Ia</td>
			<td >Sigma</td>
			<td>C2674</td>
			<td>Dilute in 10ml PBS to get a final concentration of 10mg/ml. Store at -20&#176;C in 1ml aliquots.</td>
		</tr>
		<tr >
			<td >Dulbecco&#39;s PBS</td>
			<td >Sigma</td>
			<td >D8662</td>
			<td>With calcium and magnesium chloride. Keep sterile and store at room temperature.</td>
		</tr>
		<tr >
			<td >1X Medium M199</td>
			<td >Gibco</td>
			<td >31150-022</td>
			<td>Warm in 37 &#176;C water bath before use.</td>
		</tr>
		<tr >
			<td >Gentamicin sulphate</td>
			<td >Sigma</td>
			<td >G1397</td>
			<td>Store at 4&#176;C. Add to M199 500ml bottle.</td>
		</tr>
		<tr >
			<td >Human epidermal growth factor</td>
			<td >Sigma</td>
			<td >E9644</td>
			<td>Store at -20&#176;C in 10&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >Fetal calf serum (FCS)</td>
			<td >Sigma</td>
			<td >F9665</td>
			<td >FCS must be batch tested to ensure the growth and viability of isolated EC. Heat inactivate at 56&#176;C. Store in 10ml aliquots at -20&#176;C.</td>
		</tr>
		<tr >
			<td >Amphotericin B</td>
			<td >Gibco</td>
			<td >15290-026</td>
			<td >Potent and becomes toxic within a week so fresh complete HUVEC medium must be made up every week. Store at -20&#176;C in 1ml aliquots.</td>
		</tr>
		<tr >
			<td >Hydrocortisone</td>
			<td >Sigma</td>
			<td >H0135</td>
			<td>Stock is in ethanol. Store at -20&#176;C in 10&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >Collagenase Type II</td>
			<td >Sigma</td>
			<td >C6885</td>
			<td>Dilute stock in PBS to a final concentration of 100mg/ml. Store at -20&#176;C in 100&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >Hyaluronidase</td>
			<td >Sigma</td>
			<td >H3631</td>
			<td>Dilute stock in PBS to a final concentration of 20,000U/ml. Store at -20&#176;C in 100&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >100&#181;m cell strainer for 50ml centifuge tube</td>
			<td >Scientific Lab Supplies (SLS)</td>
			<td >352360</td>
			<td >Other commercially available cell strainers (e.g. Greiner bio-one) can also be used.</td>
		</tr>
		<tr >
			<td >DMEM low glucose</td>
			<td >Biosera</td>
			<td >LM-D1102/500</td>
			<td>Warm in 37 &#176;C water bath before use.</td>
		</tr>
		<tr >
			<td >Penicillin/Streptomycin mix</td>
			<td >Sigma</td>
			<td >P4333</td>
			<td>Store at -20&#176;C in 1ml aliquots.</td>
		</tr>
		<tr >
			<td >25cm2 tissue culture flask</td>
			<td >SLS</td>
			<td >353109</td>
			<td></td>
		</tr>
		<tr >
			<td >75cm2 tissue culture flask</td>
			<td >SLS</td>
			<td >353136</td>
			<td></td>
		</tr>
		<tr >
			<td >Bone marrow mesenchymal stem cells vial</td>
			<td >Lonza</td>
			<td >PT-2501</td>
			<td >Store in liquid nitrogen upon arrival. Cells are at passage 2 upon arrival but are designated passage 0. Exapand to passage 3 and store in liquid nitrogen for later use.</td>
		</tr>
		<tr >
			<td >Mesenchymal stem cell growth medium (MSCGM)</td>
			<td >Lonza</td>
			<td >PT-3001</td>
			<td>Warm in 37 &#176;C water bath before use. For Cell Tracker Green staining use medium without FCS.</td>
		</tr>
		<tr >
			<td >EDTA (0.02%) solution</td>
			<td >Sigma</td>
			<td >E8008</td>
			<td>Store at 4&#176;C. Warm in 37&#176;C water bath before use.</td>
		</tr>
		<tr >
			<td >Trypsin solution</td>
			<td >Sigma</td>
			<td >T4424</td>
			<td>Store at -20&#176;C in 2ml aliquots. Thaw at room temperature and use immediately.</td>
		</tr>
		<tr >
			<td >Cryovials</td>
			<td >Greiner bio-one</td>
			<td>2019-02</td>
			<td>Keep on ice before adding before adding cell suspension.</td>
		</tr>
		<tr >
			<td >Mr. Frosty Freezing Container</td>
			<td >Nalgene</td>
			<td >5100-0001</td>
			<td >Store at room temperature. When adding cryovials with cells store at -80&#176;C for 24h before transfrring cells to liquid nitrogen.</td>
		</tr>
		<tr >
			<td >Ibidi u-Slide VI (0.4), T/C treated, sterile</td>
			<td >Ibidi</td>
			<td >IB-80606</td>
			<td >Alternative models include glass capillaries, Cellix Biochips (www.cellixltd.com), BioFlux Plates (www.fluxionbio.com/bioflux/) and GlycoTech parallel plate flow chambers (http://www.glycotech.com/apparatus/parallel.html).</td>
		</tr>
		<tr >
			<td >Cell tracker green dye</td>
			<td >Life technologies</td>
			<td >C2925</td>
			<td>Store in 5&#181;l aliquots at -20&#176;C. Dilute in 5ml prewarmed (at 37&#176;C) MSCGM.</td>
		</tr>
		<tr >
			<td >Cell counting chambers</td>
			<td >Nexcelom</td>
			<td >SD-100</td>
			<td>Alternatively a haemocytometer can be used.</td>
		</tr>
		<tr >
			<td >Cellometer auto T4 cell counter</td>
			<td >Nexcelom</td>
			<td >Auto T4-203-0238</td>
			<td></td>
		</tr>
		<tr >
			<td >Tumor necrosis factor &#945; (TNF&#945;)</td>
			<td >R&#38;D Systems</td>
			<td >210-TA-100</td>
			<td>Dilute stock in PBS to a final concentration of 100,000U/ml. Store at -80&#176;C in 10&#181;l aliquots.</td>
		</tr>
		<tr >
			<td >6-well, 0.4&#181;m PET Transwell filters</td>
			<td >SLS</td>
			<td >353090</td>
			<td></td>
		</tr>
		<tr >
			<td >K2-EDTA in 10ml tubes</td>
			<td >Sarstedt</td>
			<td ></td>
			<td>Store at room temperature.</td>
		</tr>
		<tr >
			<td >Histopaque 1119</td>
			<td >Sigma</td>
			<td >11191</td>
			<td>Store at 4&#176;C. Warm to room temperature before use.</td>
		</tr>
		<tr >
			<td >Histopaque 1077</td>
			<td >Sigma</td>
			<td >10771</td>
			<td>Store at 4&#176;C. Warm to room temperature before use.</td>
		</tr>
		<tr >
			<td >10ml round bottomed tube</td>
			<td >Appleton Woods</td>
			<td >SC211 142 AS</td>
			<td></td>
		</tr>
		<tr >
			<td >7.5% BSA Fraction V solution</td>
			<td >Life technologies</td>
			<td >15260-037</td>
			<td>Store at 4&#176;C.</td>
		</tr>
		<tr >
			<td >20ml Plastipak syringes</td>
			<td >BD falcon</td>
			<td >300613</td>
			<td></td>
		</tr>
		<tr >
			<td >5ml Plastipak syringes</td>
			<td >BD falcon</td>
			<td >302187</td>
			<td></td>
		</tr>
		<tr >
			<td >2ml Plastipak syringes</td>
			<td >BD falcon</td>
			<td >300185</td>
			<td></td>
		</tr>
		<tr >
			<td >3M hypo-allergenic surgical tape 9m x 2.5cm</td>
			<td >Micropore</td>
			<td >1530-1</td>
			<td>Use to secure the syringe tap onto the wall of the perspex chamber.</td>
		</tr>
		<tr >
			<td >Silicon rubber tubing, internal diameter/external diameter (ID/OD) of 1/3mm (thin tubing)</td>
			<td >Fisher Scientific</td>
			<td >FB68854</td>
			<td >Cut silicon tubing to the appropriate size. All tubing leading directly to the electronic microvalve must be thin.</td>
		</tr>
		<tr >
			<td >Silicon rubber tubing ID/OD of 2/4mm (thick tubing)</td>
			<td >Fisher Scientific</td>
			<td >FB68855</td>
			<td></td>
		</tr>
		<tr >
			<td >Portex Blue Line Manometer tubing</td>
			<td>Smiths</td>
			<td >200/495/200</td>
			<td>Tubing leading to the syringe pump.</td>
		</tr>
		<tr >
			<td >3-way stopcock</td>
			<td >BOC Ohmeda AB</td>
			<td ></td>
			<td></td>
		</tr>
		<tr >
			<td >Glass 50ml syringe for pump</td>
			<td >Popper Micromate</td>
			<td >550962</td>
			<td>Must be primed prior to use by removing any air bubbles.</td>
		</tr>
		<tr >
			<td >Glass coverslip</td>
			<td >Raymond A Lamb</td>
			<td ></td>
			<td>26x76mm coverslips made to order. Lot number 2440980.</td>
		</tr>
		<tr >
			<td >Parafilm gasket</td>
			<td >American National Can Company</td>
			<td ></td>
			<td >Cut a 26x76mm piece of parafilm using an aluminium template and cut a 20x4mm slot into it using a scalpel 10a. Gasket thickness is approximately 133&#181;m.</td>
		</tr>
		<tr >
			<td >Two perspex parallel plates</td>
			<td >Wolfson Applied Technology Laboratory</td>
			<td ></td>
			<td >Specially designed chamber consisting of parallel plates held together by 8 screws. The lower plate has a viewing slot cut out in the middle and a shallow recess milled to allow space for the coverslip, filter and gasket. The upper perspex plate has an inlet and outlet hole positioned over the flow channel.</td>
		</tr>
		<tr >
			<td >Electronic 3-way microvalve with min. dead space</td>
			<td >Lee Products Ltd.</td>
			<td >LFYA1226032H</td>
			<td>Electronically connected to a 12 volt DC power supply.</td>
		</tr>
		<tr >
			<td >Syringe pump for infusion/withdrawal (PHD2000)</td>
			<td >Harvard Apparatus</td>
			<td >70-2001</td>
			<td>Set the diameter to 29mm and refill (flow) rate.</td>
		</tr>
		<tr >
			<td >L-shaped connector</td>
			<td >Labhut</td>
			<td >LE876</td>
			<td>To attach to the inlet and outlet ports onto the Ibidi microslide channel.</td>
		</tr>
		<tr >
			<td >Video camera</td>
			<td >Qimaging</td>
			<td >01-QIC-F-M-12-C</td>
			<td>Connected to a computer which enables digitall videos to be recorded.</td>
		</tr>
		<tr >
			<td >Image-Pro Plus 7.0</td>
			<td >Media Cybernetics</td>
			<td >41N70000-61592</td>
			<td >For data analysis. Manually tag cells displaying the different behaviors. Track cells for analysis of rolling and migration velocities.</td>
		</tr>
		<tr >
			<td ></td>
			<td ></td>
			<td ></td>
			<td>Refer to product datasheets for details on hazards of using the reagents described here.</td>
		</tr>
	</tbody>
</table>

analyzing the effects of stromal cells on the recruitment of leukocytes from flow

Stromal cells regulate the recruitment of circulating leukocytes during inflammation through cross-talk with neighboring endothelial cells. Here we describe two in vitro &#8220;vascular&#8221; models for studying the recruitment of circulating neutrophils from flow by inflamed endothelial cells. A major advantage of these models is the ability to analyze each step in the leukocyte adhesion cascade in order, as would occur in vivo. We also describe how both models can be adapted to study the role of stromal cells, in this case mesenchymal stem cells (MSC), in regulating leukocyte recruitment.
Primary endothelial cells were cultured alone or together with human MSC in direct contact on Ibidi microslides or on opposite sides of a Transwell filter for 24 hr. Cultures were stimulated with tumor necrosis factor alpha (TNF&#945;) for 4 hr and incorporated into a flow-based adhesion assay. A bolus of neutrophils was perfused over the endothelium for 4 min. The capture of flowing neutrophils and their interactions with the endothelium was visualized by phase-contrast microscopy.
In both models, cytokine-stimulation increased endothelial recruitment of flowing neutrophils in a dose-dependent manner. Analysis of the behavior of recruited neutrophils showed a dose-dependent decrease in rolling and a dose-dependent increase in transmigration through the endothelium. In co-culture, MSC suppressed neutrophil adhesion to TNF&#945;-stimulated endothelium.
Our flow based-adhesion models mimic the initial phases of leukocyte recruitment from the circulation. In addition to leukocytes, they can be used to examine the recruitment of other cell types, such as therapeutically administered MSC or circulating tumor cells. Our multi-layered co-culture models have shown that MSC communicate with endothelium to modify their response to pro-inflammatory cytokines, altering the recruitment of neutrophils. Further research using such models is required to fully understand how stromal cells from different tissues and conditions (inflammatory disorders or cancer) influence the recruitment of leukocytes during inflammation.

Initially, we analyzed the effect of stimulating EC with TNF&#945; on the recruitment of neutrophils from flow using the Ibidi microslide model (Section 7 - 9). In the absence of TNF&#945;, little if any neutrophils adhered to the endothelial monolayer (Figure 2A). This was expected, as untreated/resting EC do not express the necessary adhesion molecules (selectins) or chemokines to support binding25,26. In contrast, cytokine-stimulation significantly increased neutrophil adhe...

Watch this Scientific Journal Video about Analyzing the Effects of Stromal Cells on the Recruitment of Leukocytes from Flow at JoVE.com

Analyzing the Effects of Stromal Cells on the Recruitment of Leukocytes from Flow

The ability of inflamed endothelium to recruit leukocytes from flow is regulated by mesenchymal stromal cells. We describe two in vitro models incorporating primary human cells that can be used to assess neutrophil recruitment from flow and examine the role that mesenchymal stromal cells play in regulating this process.

Stromal cells regulate the recruitment of circulating leukocytes during inflammation through cross-talk with neighboring endothelial cells. Here we ...

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JoVE Journal

Immunology and Infection

10.1K Views.  University of Birmingham. The ability of inflamed endothelium to recruit leukocytes from flow is regulated by mesenchymal stromal cells. We describe two in vitro models incorporating primary human cells that can be used to assess neutrophil recruitment from flow and examine the role that mesenchymal stromal cells play in regulating this process.