Name: mesenchymal stem cell regulation of macrophage phagocytosis; quantitation and imaging
Uploaded: 2021-07-16T14:00:00
Description: Watch this Scientific Journal Video about Mesenchymal Stem Cell Regulation of Macrophage Phagocytosis; Quantitation and Imaging at JoVE.com

This work was supported by the NSF Major Research Instrument mechanism under grant numbers 1626093 and 1919583.

NOTE: All medium preparation and cell culture techniques are carried out under aseptic conditions using a biosafety cabinet with laminar flow. All culture incubation steps described are carried out using an incubator designed to maintain an atmosphere of 37 &#176;C, 5% CO2, and 95% humidity.
1. Cell culture
<ol>
	<li>Preparation of growth medium
	<ol>
		<li>For MSC and LADMAC, add 50 mL of FBS and 5 mL of 100x antibiotic/antimycotic mix to 500 mL of high glucose DMEM.</li>
		<li>F...

<ol>
	<li>Phinney, D. G., Prockop, D. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concise+review:+Mesenchymal+stem/multipotent+stromal+cells:+The+state+of+transdifferentiation+and+modes+of+tissue+repair--current+views.">Concise review: Mesenchymal stem/multipotent stromal cells: The state of transdifferentiation and modes of tissue repair--current views.</a> Stem Cells. 25 (11), 2896-2902 (2007).</li><li>Bernardo, M. E., Fibbe, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesenchymal+stromal+cells:+sensors+and+switchers+of+inflammation.">Mesenchymal stromal cells: sensors and switchers of inflammation.</a> Cell Stem Cell. 13 (4), 392-402 (2013).</li><li>Tobin, L. M., Healy, M. E., English, K., Mahon, B. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+mesenchymal+stem+cells+suppress+donor+CD4(+)+T+cell+proliferation+and+reduce+pathology+in+a+humanized+mouse+model+of+acute+graft-versus-host+disease.">Human mesenchymal stem cells suppress donor CD4(+) T cell proliferation and reduce pathology in a humanized mouse model of acute graft-versus-host disease.</a> Clinical and Experimental Immunology. 172 (2), 333-348 (2013).</li><li>Giuliani, 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=Long-lasting+inhibitory+effects+of+fetal+liver+mesenchymal+stem+cells+on+T-lymphocyte+proliferation.">Long-lasting inhibitory effects of fetal liver mesenchymal stem cells on T-lymphocyte proliferation.</a> PLoS One. 6 (5), 19988 (2011).</li><li>Plumas, J., Chaperot, L., Richard, M. J., Molens, J. P., Bensa, J. C., Favrot, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesenchymal+stem+cells+induce+apoptosis+of+activated+T+cells.">Mesenchymal stem cells induce apoptosis of activated T cells.</a> Leukemia. 19 (9), 1597-1604 (2005).</li><li>Luz-Crawford, P., 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=Mesenchymal+stem+cells+generate+a+CD4+CD25+Foxp3++regulatory+T+cell+population+during+the+differentiation+process+of+Th1+and+Th17+cells.">Mesenchymal stem cells generate a CD4+CD25+Foxp3+ regulatory T cell population during the differentiation process of Th1 and Th17 cells.</a> Stem Cell Research &amp; Therapy. 4 (3), 65 (2013).</li><li>Waterman, R. S., Tomchuck, S. L., Henkle, S. L., Betancourt, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+mesenchymal+stem+cell+(MSC)+paradigm:+Polarization+into+a+pro-inflammatory+MSC1+or+an+Immunosuppressive+MSC2+phenotype.">A new mesenchymal stem cell (MSC) paradigm: Polarization into a pro-inflammatory MSC1 or an Immunosuppressive MSC2 phenotype.</a> PLoS One. 5 (4), 10088 (2010).</li><li>Nemeth, K., 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=marrow+stromal+cells+attenuate+sepsis+via+prostaglandin+E(2)-dependent+reprogramming+of+host+macrophages+to+increase+their+Interleukin-10+production.">marrow stromal cells attenuate sepsis via prostaglandin E(2)-dependent reprogramming of host macrophages to increase their Interleukin-10 production.</a> Nature Medicine. 15 (1), 42-49 (2009).</li><li>Maggini, 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=Mouse+Bone+Marrow-Derived+Mesenchymal+Stromal+Cells+Turn+Activated+Macrophages+into+a+Regulatory-Like+Profile.">Mouse Bone Marrow-Derived Mesenchymal Stromal Cells Turn Activated Macrophages into a Regulatory-Like Profile.</a> PLoS One. 5 (2), 9252 (2010).</li><li>Takizawa, 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=marrow-derived+mesenchymal+stem+cells+propagate+immunosuppressive/anti-inflammatory+macrophages+in+cell-to-cell+contact-independent+and-dependent+manners+under+hypoxic+culture.">marrow-derived mesenchymal stem cells propagate immunosuppressive/anti-inflammatory macrophages in cell-to-cell contact-independent and-dependent manners under hypoxic culture.</a> Experimental Cell Research. 358 (2), 411-420 (2017).</li><li>Kim, J., Hematti, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mesenchymal+stem+cell-educated+macrophages:+a+novel+type+of+alternatively+activated+macrophages.">Mesenchymal stem cell-educated macrophages: a novel type of alternatively activated macrophages.</a> Experimental Hematology. 37 (12), 1445-1453 (2009).</li><li>Evans, J. F., Salvador, V., George, S., Trevino-Gutierrez, C., Nunez, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+aorta-derived+mesenchymal+progenitor+cells+contribute+to+and+enhance+the+immune+response+of+macrophage+cells+under+inflammatory+conditions.">Mouse aorta-derived mesenchymal progenitor cells contribute to and enhance the immune response of macrophage cells under inflammatory conditions.</a> Stem Cell Research &amp; Therapy. 6 (1), 56 (2015).</li><li>Cho, D. I., 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=Mesenchymal+stem+cells+reciprocally+regulate+the+M1/M2+balance+in+mouse+bone+marrow-derived+macrophages.">Mesenchymal stem cells reciprocally regulate the M1/M2 balance in mouse bone marrow-derived macrophages.</a> Experimental Molecular Medicine. 46, 70 (2014).</li><li>Fernandez, 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=Mouse+mesenchymal+progenitor+cells+expressing+adipogenic+and+osteogenic+transcription+factors+suppress+the+macrophage+inflammatory+response.">Mouse mesenchymal progenitor cells expressing adipogenic and osteogenic transcription factors suppress the macrophage inflammatory response.</a> Stem Cells International. 2017, 5846257 (2017).</li><li>Jackson, M. 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=Mitochondrial+transfer+via+tunneling+nanotubes+is+an+important+mechanism+by+which+mesenchymal+stem+cells+enhance+macrophage+phagocytosis+in+the+in+vitro+and+in+vivo+models+of+ARDS.">Mitochondrial transfer via tunneling nanotubes is an important mechanism by which mesenchymal stem cells enhance macrophage phagocytosis in the in vitro and in vivo models of ARDS.</a> Stem Cells. 34 (8), 2210-2223 (2016).</li><li>Chaplin, D. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Overview+of+the+immune+response.">Overview of the immune response.</a> The Journal of Allergy and Clinical Immunology. 125 (2), 3-23 (2010).</li><li>Lim, 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=Characterizing+the+mechanisms+of+nonopsonic+uptake+of+cryptococci+by+macrophages.">Characterizing the mechanisms of nonopsonic uptake of cryptococci by macrophages.</a> Journal of Immunology. 200 (10), 3539-3546 (2018).</li><li>Wang, Z., 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=Interferon-&#947;+inhibits+nonopsonized+phagocytosis+of+macrophages+via+an+mTORC1-c/EBP+pathway.">Interferon-&#947; inhibits nonopsonized phagocytosis of macrophages via an mTORC1-c/EBP pathway.</a> Journal of Innate Immunity. 7 (2), 165-176 (2015).</li><li>Lindner, B., Burkard, T., Schuler, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phagocytosis+assays+with+different+PH-sensitive+fluorescent+particles+and+various+readouts.">Phagocytosis assays with different PH-sensitive fluorescent particles and various readouts.</a> Biotechniques. 68, 245-250 (2020).</li><li>Kapellos, T. 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=A+novel+real+time+imaging+platform+to+quantify+macrophage+pahgocytosis.">A novel real time imaging platform to quantify macrophage pahgocytosis.</a> Biochemical Pharmacology. 116, 107-119 (2016).</li><li>Takahashi, D., 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=Flow+cytometric+quantitation+of+platelet+phagocytosis+by+monocytes+using+a+pH-sensitive+dye,+pHrodo-SE.">Flow cytometric quantitation of platelet phagocytosis by monocytes using a pH-sensitive dye, pHrodo-SE.</a> Journal of Immunological Methods. 447, 57-64 (2017).</li></ol>

Analysis of phagocytosis using bioparticles conjugated to a pH-sensitive dye is a relatively new tool that has proven advantageous over traditional fluorescently labeled particles12,19,20. With traditional fluorescent-labeled particles, only end-point analysis is feasible. Detection is carried out with fluorescent microscopy and/or spectrofluorometry after washing or quenching particles that have not been taken up by the phagocy...

Mesenchymal stem cells (MSC) are progenitor cells that give rise to connective tissue cells. MSC are present in adult mammalian tissues and can be isolated from the bone marrow1. Due to their immunomodulatory properties, these cells are widely studied2. Early studies focused on MSC regulation of T-cells3,4,5,6 but more recently, their regulation of macrophage cells (M&#934;), a major cellular component of innate immunity, has received increased attention7,8,9,10,11,12,13,14. The importance of MSC-M&#934; interaction in the treatment of inflammatory disease is underscored by the fact that depletion of monocytes/macrophages abrogates the therapeutic effects of MSC in animal models8. Here, the focus is the cell contact interaction of the MSC with M&#934;. MSC&#160;have the capacity to&#160;regulate the phenotype of M&#934; by promoting the switch from inflammatory to anti-inflammatory responses, leading to tissue repair activities8,9,10,11, and much has been done to demonstrate these regulatory mechanisms. Under other circumstances, MSC can support or exacerbate a&#160;M&#934;-driven inflammatory response12,13 and enhance M&#934; phagocytic activity14,15. However, there is a critical lack of existing data that identifies the mechanisms whereby and the conditions under which MSC regulate M&#934; phagocytic activity.
M&#934; have families of receptors that recognize either opsonized (antibody or complement coated) or non-opsonized pathogens leading to phagocytosis16. The activation and activity of the latter is less well studied17. In a non-inflammatory in vitro environment, MSC&#160;enhance M&#934; phagocytosis of non-opsonized pathogens13. However, recognition of non-opsonized pathogens by M&#934; may be reduced after exposure to an inflammatory environment produced by lymphocytes during an adaptive immune response. IFN-&#947;, released by natural killer cells and effector lymphocytes, has an inhibitory effect on M&#934; phagocytosis of non-opsonized particles18. A co-culture model was developed to study the mechanisms of MSC direct contact regulation of M&#934; phagocytosis. The goal of the experiment presented here is to determine whether MSC&#160;regulate M&#934; phagocytosis of non-opsonized pathogens after M&#934; have been exposed to IFN-&#947; (Figure 1).

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>96 Well Black Polystyrene Microplate</td>
			<td>MilliporeSigma</td>
			<td>CLS3603-48EA</td>
			<td></td>
		</tr>
		<tr>
			<td>0.4% trypan blue solution</td>
			<td>MilliporeSigma</td>
			<td>T8154-20ML</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL and 50 mL Conical Sterile Polypropylene Centrifuge Tubes</td>
			<td>ThermoFisher</td>
			<td>339653</td>
			<td></td>
		</tr>
		<tr>
			<td>4-well Chambered Coverglass w/ non-removable wells</td>
			<td>ThermoFisher</td>
			<td>155382PK</td>
			<td></td>
		</tr>
		<tr>
			<td>Antibiotic-Antimycotic (100X)&#160;Gibco</td>
			<td>ThermoFisher</td>
			<td>15240096</td>
			<td></td>
		</tr>
		<tr>
			<td>Axiobserver 7 Imaging System</td>
			<td>Zeiss</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin (BSA)</td>
			<td>MilliporeSigma</td>
			<td>A8806-1G</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell lifter</td>
			<td>MilliporeSigma</td>
			<td>CLS3008-100EA</td>
			<td></td>
		</tr>
		<tr>
			<td>Culture flasks, tissue culture treated, surface area 75&#160;cm2, canted neck, with cap, filtered</td>
			<td>MilliporeSigma</td>
			<td>C7231-120EA</td>
			<td></td>
		</tr>
		<tr>
			<td>D1 ORL UVA [D1]</td>
			<td>ATCC</td>
			<td>CRL-12424</td>
			<td>Mouse MSC Cell Line</td>
		</tr>
		<tr>
			<td>DMEM, High Glucose</td>
			<td>ThermoFisher</td>
			<td>11965092</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum, qualified, heat inactivated</td>
			<td>ThermoFisher</td>
			<td>16140071</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>FisherScientific</td>
			<td>02-671-51B</td>
			<td></td>
		</tr>
		<tr>
			<td>I-11.15</td>
			<td>ATCC</td>
			<td>CRL-2470</td>
			<td>Mouse M&#934; Cell Line</td>
		</tr>
		<tr>
			<td>LADMAC Cell Line</td>
			<td>ATCC</td>
			<td>CRL-2420</td>
			<td>LADMAC cells secrete the growth factor colony stimulating factor 1 (CSF-1).</td>
		</tr>
		<tr>
			<td>Live-Cell Imaging solution</td>
			<td>ThermoFisher</td>
			<td>A14291DJ</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS, pH 7.4</td>
			<td>ThermoFisher</td>
			<td>10010031</td>
			<td></td>
		</tr>
		<tr>
			<td>pHrodo Green Zymosan Bioparticles Conjugate</td>
			<td>ThermoFisher</td>
			<td>P35365</td>
			<td></td>
		</tr>
		<tr>
			<td>Recombinant Murine IFN-&#947;</td>
			<td>Preprotech</td>
			<td>315-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Spectramax i3X</td>
			<td>Molecular Devices</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile Single Use Vacuum Filter Units, 250 mL, 0.2 &#181;m</td>
			<td>ThermoFisher</td>
			<td>568-0020</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile syringe filters, 0.2 micrometer</td>
			<td>ThermoFisher</td>
			<td>723-2520</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue-culture treated culture dishes, 100 mm x 20 mm</td>
			<td>MilliporeSigma</td>
			<td>CLS430167-100EA</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin-EDTA (0.05%), phenol red</td>
			<td>ThermoFisher</td>
			<td>25300054</td>
			<td></td>
		</tr>
	</tbody>
</table>

mesenchymal stem cell regulation of macrophage phagocytosis; quantitation and imaging

Mesenchymal stem cells (MSC) have traditionally been studied for their regenerative properties, but more recently, their immunoregulatory characteristics have been at the forefront. They interact with and regulate immune cell activity. The focus of this study is the MSC regulation of macrophage phagocytic activity. Macrophage (M&#934;) phagocytosis is an important part of the innate immune system response to infection, and the mechanisms through which MSC modulate this response are under active investigation. Presented here is a method to study M&#934; phagocytosis of non-opsonized zymosan particles conjugated to a pH-sensitive fluorescent molecule while in co-culture with MSC. As phagocytic activity increases and the labeled zymosan particles are enclosed within the acidic environment of the phagolysosome, the fluorescence intensity of the pH-sensitive molecule increases. With the appropriate excitation and emission wavelengths, phagocytic activity is measured using a fluorescent spectrophotometer and kinetic data is presented as changes in relative fluorescent units over a 70 min period. To support this quantitative data, the change in the phagocytic activity is visualized using dynamic imaging. Results using this method demonstrate that when in co-culture, MSC enhance M&#934; phagocytosis of non-opsonized zymosan of both naive and IFN-&#947; treated M&#934;. These data add to the current knowledge of MSC regulation of the innate immune system. This method can be applied in future investigations to fully delineate the underlying cellular and molecular mechanisms.

After calculating mean &#177; SEM for each group at all time points, the data is presented in line graph format with the Y-axis as the Relative Fluorescent Intensity and the X-axis as Time. Supplementary File 1 provides an example of raw data from a kinetic read of the 96-well plate in a spreadsheet format.
In this study, the optimal results presented in Figure 3A, and Table 3 demonstrate that 1) co-culture with MSC&#160;enhances ...

Watch this Scientific Journal Video about Mesenchymal Stem Cell Regulation of Macrophage Phagocytosis; Quantitation and Imaging at JoVE.com

Mesenchymal Stem Cell Regulation of Macrophage Phagocytosis; Quantitation and Imaging

Presented here is a protocol to quantify and produce dynamic images of mesenchymal stem cell (MSC) mediated regulation of macrophage (M&#934;) phagocytosis of non-opsonized yeast (zymosan) particles that are conjugated to a pH-sensitive fluorescent molecule.

Mesenchymal stem cells (MSC) have traditionally been studied for their regenerative properties, but more recently, their immunoregulatory characteristics ...

This co-culture method will help answer key questions surrounding the cell contact mechanisms behind mesenchymal stem cell regulation of macrophage phagocytosis, and therefore illuminate the role of MSC in regulating innate immunity. This technique can be applied in high-throughput analyses. The bioparticles conjugated to pH-sensitive dyes fluoresce only in acidic phagolysosome environments.Hence, washing and quenching are necessary. This method can also be applied to a variety of co-culture models that include neutrophils and other phagocytes. Demonstrating the procedure will be Ethan Chetkof, an undergraduate currently in my lab.To begin with, observe the confluency of cultured mesenchymal stem cells. When 70-80%confluency is achieved, aspirate the growth medium from the cultured cells in a 100 millimeter dish and add five milliliters of PBS. After aspirating the PBS, add two milliliters of 0.05%trypsin EDTA solution and incubate the cells for three minutes.After three minutes, check the cell detachment using an inverted microscope. And if the cells are not detached, incubate for one to two minutes again. Once all the cells are detached, add five milliliters of fresh growth medium to the plate.After rinsing the plate using the trypsin medium mixture, use a sterile serological pipette to collect cells into a clean, sterile 50 milliliter conical tube. Next, pellet down the cells by centrifugation. After aspirating the supernatant, resuspend the cell pellet in 10 milliliters of fresh growth medium by gently pipetting up and down.For cell counting, add 10 microliters of cell suspension into a 1.5 milliliter microcentrifuge tube containing 30 microliters of 0.4%Trypan Blue solution, then add 10 microliters of the mixture under the coverslip of a hemocytometer counting chamber. Under the inverted or Brightfield microscope, count the unstained viable cells using a 10X objective lens and four one-square millimeter chambers and calculate the cell number as described in the text manuscript. Use the equation C1V1 equals C2V2 to determine the desired volume of the fresh medium and cell suspension required to prepare the cell suspension at a final concentration of one times 10 to the fifth cells per milliliter.Use a multi-channel micropipetter to add 100 microliters of the cell suspension in the wells of a 96-well plate according to the plate design. Use a micropipette to add 530 microliters of the cell suspension to each one of the chamber slide according to the plate design and incubate overnight. Prepare 10 milliliters of activation medium containing interferon gamma at a concentration of 250 nanograms per milliliter for activating the macrophage cells in one 100-millimeter dish.Aspirate the growth medium from the macrophage cell cultures and rinse the cells with five milliliters of the activation medium devoid of interferon gamma. After aspirating the rinsing medium in the experimental dish, add 10 milliliters of activation medium supplemented with interferon gamma. And in the control dish, add 10 milliliters of activation medium without interferon gamma, then incubate the cells for 16 to 24 hours.At the end of the incubation, for preparing the co-cultures, remove the activation medium from the macrophage cells and add five milliliters of fresh growth medium. Use a cell lifter to gently scrape the cells and collect the cells into a 50 milliliter conical tube. Next, count the cells using Trypan Blue exclusion and hemocytometry, followed by preparation of control and treated macrophage cell suspensions at the concentration of two times 10 to the fifth cells per milliliter as demonstrated previously for the mesenchymal stem cells.Gently aspirate the medium from the experimental wells containing mesenchymal stem cells. Use a multi-channel micropipette to add 100 microliters of the treated and the control macrophage cell suspensions in the appropriate experimental wells according to the plate design and incubate overnight as demonstrated. Gently aspirate the medium from the four-walled chamber slide containing mesenchymal stem cells.Use a micropipette to add 530 microliters of the macrophage cell suspension to the appropriate wells according to the design and incubate overnight. Add one milliliter of live cell imaging medium to the vial containing one milligram of Zymosan particles and collect the medium particle mixture into a glass culture tube. After rinsing the vial with an additional one milliliter of imaging solution, transfer the rinsed imaging medium in the glass tube, then add three milliliters of additional imaging solution to achieve 0.2 milligrams per milliliter Zymosan particle suspension.Vortex the Zymosan suspension using quick pulses for 30 to 60 seconds, then use a probe sonicator to sonicate the suspension with 60 quick pulses. After aspirating the medium, rinse the experimental wells and reagent blank wells with 100 microliters of live cell imaging solution. Next, aspirate the live cell imaging solution from the wells and add 100 microliters of the Zymosan suspension.Open the plate tray of the fluorescent reader using the touch pad interface. Set the plate without the lid in the tray with the A1 well in the upper left corner. Close the tray using the touch pad and click on the green read button in the top menu.To conduct the phagocytosis assay, after rinsing the first experimental well with 750 microliters of the imaging medium, add 400 microliters of the Zymosan suspension leaving the remaining wells in the growth medium. Next, place the slide on the incubated stage of the imaging system. Use the imaging software.Select the Brightfield option under the locate tab, and then click on the eyepiece icon. With the 10X objective in place, use the eyepiece and focusing knob to focus on the cells. Select the acquisition tab.Open the experiment dropdown menu and select a set of wavelengths that includes EGFP filter set to accommodate 509 nanometers excitation and 533 nanometers emission wavelengths of the pH-sensitive dye. When about two minutes are left on the timer, click on the 20X icon in the objective menu to change the objective to 20X, then click on the channels menu, select EGFP filters, and in the exposure menu, set the exposure time to 400 milliseconds to detect the pH-sensitive green fluorophore, and then click on live. After adjusting the focus, click on stop to turn off the light and check the box next to the top time-lapse experimental setting.In the focusing strategy menu, select software auto-focus and from the dropdown menu, select smart and core settings to reduce the time of exposure to light while the auto-focus is running. In the time-lapse menu, set the desired number of acquisitions to 30 to 60, the interval time to one minute, and then click on the start experiment button to begin the acquisition. The effect of interferon gamma on the co-culture was studied.The representative results demonstrate that the co-culture of macrophages with mesenchymal stem cells enhances the phagocytic activity of the macrophage. Interferon gamma treatment reduces the activity of the macrophage. However, in the presence of mesenchymal stem cells, the macrophage phagocytic activity was partially rescued.The optimal cell densities are critical in these studies. And when the macrophage cells were plated at too low of a density, changes in fluorescence intensity were not detected. When the macrophage cells were plated at a high density, the fluorescence intensity was elevated rapidly in all groups and differences were not discerned.One of the most important things during this procedure is to ensure that the cell densities are optimized and kept consistent between experiments.

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Inflammation is a fundamental aspect of many human diseases. In this video report, we demonstrate non-invasive bioluminescence imaging techniques that ...

Large-Scale Purification of Porcine or Bovine Photoreceptor Outer Segments for Phagocytosis Assays on Retinal Pigment Epithelial Cells

Analysis of one of the vital functions of retinal pigment epithelial (RPE) cells, the phagocytosis of spent aged distal fragments of photoreceptor outer ...

High Throughput Fluorometric Technique for Assessment of Macrophage Phagocytosis and Actin Polymerization

The goal of fluorometric analysis is to serve as an efficient, cost effective, high throughput method of analyzing phagocytosis and other cellular ...

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans

Cryptococcosis is a life-threatening infection caused by pathogenic fungi of the genus Cryptococcus. Infection occurs upon inhalation of spores, which are ...

Assessment of the Immunomodulatory Properties of Human Mesenchymal Stem Cells (MSCs)

Assessment of the Immunomodulatory Properties of Human Mesenchymal Stem Cells MSCs

The immunomodulatory properties of multilineage human mesenchymal stem cells (MSCs) appear to be highly relevant for clinical use towards a wide-range of ...

Saturated Fatty Acids Induce Ceramide-associated Macrophage Cell Death

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

Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages

Phagocytosis plays a key role in host defense, as well as in tissue development and maintenance, and involves rapid, receptor-mediated rearrangements of ...