Name: isolation of adipogenic and fibro-inflammatory stromal cell subpopulations from murine intra-abdominal adipose depots
Uploaded: 2020-08-16T14:00:00
Description: Read this Scientific Article Protocol about Isolation of Adipogenic and Fibro-Inflammatory Stromal Cell Subpopulations from Murine Intra-Abdominal Adipose Depots at JoVE.com

The authors are grateful to Lisa Hansen and Kirsten Vestergaard for excellent technical assistance, and P. Scherer, N. Joffin, and C. Crewe for critical reading of the manuscript. The authors thank the UTSW Flow Cytometry Core for excellent guidance and assistance in developing the protocols described here. R.K.G. is supported by NIH NIDDK R01 DK104789, NIDDK RC2 DK118620, and NIDDK R01 DK119163. J.P. is sponsored by a pre-doctoral award from Innovation Fund Denmark.

All animal protocols and procedures have been approved by the University of Texas Southwestern Medical Center Institutional Animal Use and Care Committee.
1. Isolation of stromal vascular fraction (SVF) from gonadal white adipose tissue
<ol>
	<li>Dissect the gonadal white adipose tissue from 6-8-week-old mice and place fat pads in 1x PBS solution.</li>
	<li>Combine up to 4 fat depots (2-4 depots from 1-2 mice recommended) and mince the tissue in a 10 mL beaker containing 200 &#181;L of diges...

<ol>
	<li>Ouchi, N., Parker, J. L., Lugus, J. J., Walsh, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipokines+in+inflammation+and+metabolic+disease.">Adipokines in inflammation and metabolic disease.</a> Nature Reviews Immunology. 11 (2), 85-97 (2011).</li><li>Rosen, E. D., Spiegelman, B. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=What+we+talk+about+when+we+talk+about+fat.">What we talk about when we talk about fat.</a> Cell. 156 (1-2), 20-44 (2014).</li><li>Funcke, J. B., Scherer, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beyond+adiponectin+and+leptin:+adipose+tissue-derived+mediators+of+inter-organ+communication.">Beyond adiponectin and leptin: adipose tissue-derived mediators of inter-organ communication.</a> Journal of Lipid Research. 60 (10), 1648-1684 (2019).</li><li>Eto, H., 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=Characterization+of+structure+and+cellular+components+of+aspirated+and+excised+adipose+tissue.">Characterization of structure and cellular components of aspirated and excised adipose tissue.</a> Plastic and Reconstructive Surgery. 124 (4), 1087-1097 (2009).</li><li>Hirsch, J., Batchelor, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue+cellularity+in+human+obesity.">Adipose tissue cellularity in human obesity.</a> Clinics in Endocrinology and Metabolism. 5 (2), 299-311 (1976).</li><li>Ghaben, A. L., Scherer, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipogenesis+and+metabolic+health.">Adipogenesis and metabolic health.</a> Nature Reviews Molecular Cell Biology. 20 (4), 242-258 (2019).</li><li>Hepler, C., Gupta, R. 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E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adipose+tissue+remodeling+and+obesity.">Adipose tissue remodeling and obesity.</a> Journal of Clinical Investigation. 121 (6), 2094-2101 (2011).</li><li>Kloting, 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=Insulin-sensitive+obesity.">Insulin-sensitive obesity.</a> American Journal of Physiology-Endocrinology and Metabolism. 299 (3), 506-515 (2010).</li><li>Vishvanath, L., Gupta, R. 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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=A+stromal+cell+population+that+inhibits+adipogenesis+in+mammalian+fat+depots.">A stromal cell population that inhibits adipogenesis in mammalian fat depots.</a> Nature. 559 (7712), 103-108 (2018).</li><li>Bagchi, D. P., MacDougald, O. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+and+Dissection+of+Diverse+Mouse+Adipose+Depots.">Identification and Dissection of Diverse Mouse Adipose Depots.</a> Journal of Visualized Experiments. (149), e59499 (2019).</li><li>Jeffery, E., Church, C. D., Holtrup, B., Colman, L., Rodeheffer, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+depot-specific+activation+of+adipocyte+precursor+cells+at+the+onset+of+obesity.">Rapid depot-specific activation of adipocyte precursor cells at the onset of obesity.</a> Nature Cell Biology. 17 (4), 376-385 (2015).</li><li>Kim, S. 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=Loss+of+white+adipose+hyperplastic+potential+is+associated+with+enhanced+susceptibility+to+insulin+resistance.">Loss of white adipose hyperplastic potential is associated with enhanced susceptibility to insulin resistance.</a> Cell Metabolism. 20 (6), 1049-1058 (2014).</li><li>Vishvanath, 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=Pdgfrbeta++Mural+Preadipocytes+Contribute+to+Adipocyte+Hyperplasia+Induced+by+High-Fat-Diet+Feeding+and+Prolonged+Cold+Exposure+in+Adult+Mice.">Pdgfrbeta+ Mural Preadipocytes Contribute to Adipocyte Hyperplasia Induced by High-Fat-Diet Feeding and Prolonged Cold Exposure in Adult Mice.</a> Cell Metabolism. 23 (2), 350-359 (2016).</li><li>Wang, Q. A., Tao, C., Gupta, R. K., Scherer, P. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tracking+adipogenesis+during+white+adipose+tissue+development,+expansion+and+regeneration.">Tracking adipogenesis during white adipose tissue development, expansion and regeneration.</a> Nature Medicine. 19 (10), 1338-1344 (2013).</li><li>Gao, Z., Daquinag, A. C., Su, F., Snyder, B., Kolonin, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PDGFRalpha/PDGFRbeta+signaling+balance+modulates+progenitor+cell+differentiation+into+white+and+beige+adipocytes.">PDGFRalpha/PDGFRbeta signaling balance modulates progenitor cell differentiation into white and beige adipocytes.</a> Development. 145 (1), 155861 (2018).</li><li>Rodeheffer, M. S., Birsoy, K., Friedman, 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=Identification+of+white+adipocyte+progenitor+cells+in+vivo.">Identification of white adipocyte progenitor cells in vivo.</a> Cell. 135 (2), 240-249 (2008).</li><li>Church, C. D., Berry, R., Rodeheffer, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+study+of+adipocyte+precursors.">Isolation and study of adipocyte precursors.</a> Methods Enzymol. 537, 31-46 (2014).</li><li>Buffolo, 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=Identification+of+a+Paracrine+Signaling+Mechanism+Linking+CD34(high)+Progenitors+to+the+Regulation+of+Visceral+Fat+Expansion+and+Remodeling.">Identification of a Paracrine Signaling Mechanism Linking CD34(high) Progenitors to the Regulation of Visceral Fat Expansion and Remodeling.</a> Cell Reports. 29 (2), 270-282 (2019).</li><li>Shao, 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=De+novo+adipocyte+differentiation+from+Pdgfrbeta(+)+preadipocytes+protects+against+pathologic+visceral+adipose+expansion+in+obesity.">De novo adipocyte differentiation from Pdgfrbeta(+) preadipocytes protects against pathologic visceral adipose expansion in obesity.</a> Nature Communications. 9 (1), 890 (2018).</li><li>Lee, P. Y., Wang, J. X., Parisini, E., Dascher, C. C., Nigrovic, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ly6+family+proteins+in+neutrophil+biology.">Ly6 family proteins in neutrophil biology.</a> Journal of Leukocyte Biology. 94 (4), 585-594 (2013).</li><li>Vijay, 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=Single-cell+analysis+of+human+adipose+tissue+identifies+depot+and+disease+specific+cell+types.">Single-cell analysis of human adipose tissue identifies depot and disease specific cell types.</a> Nature Metabolism. 2 (1), 97-109 (2020).</li></ol>

The C57BL/6 strain of mice is the most used mouse strain in studies of diet-induced obesity. C57BL/6 mice rapidly gain weight when placed on a high-fat diet (HFD) and develop some of the prominent features of metabolic syndrome associated with obesity (e.g., insulin resistance and hyperlipidemia). Notably, WAT expansion occurring in association with high-fat diet (HFD) feeding occurs in a depot-specific manner19,20,21,</sup...

White adipose tissue (WAT) represents the principal site for energy storage in mammals. Within this tissue, adipocytes, or &#8220;fat cells,&#8221; store excess calories in the form of triglyceride, packaged into large unilocular lipid droplets. Moreover, adipocytes secrete a multitude of factors that regulate various aspects of energy homeostasis1,2,3. Adipocytes constitute the bulk of WAT volume; however, adipocytes only represent less than 50% of total cells found in WAT4,5. The non-adipocyte compartment of WAT, or stromal-vascular fraction (SVF), is quite heterogeneous and contains vascular endothelial cells, tissue-resident immune cells, fibroblasts, and adipocyte precursor cell (APC) populations.
WAT is exceptional in its remarkable capacity to expand in size as the demand for energy storage increases. Maintaining this tissue plasticity is essential as adequate storage of lipids in WAT protects against deleterious ectopic lipid deposition into non-adipose tissues6. The manner by which individual WAT depots undergo this expansion in response to caloric excess is a critical determinant of insulin sensitivity in the setting of obesity7. Pathologic WAT expansion, observed in obese individuals with metabolic syndrome, is characterized by preferential expansion of visceral WAT depots at the expense of metabolically favorable subcutaneous fat tissue. Moreover, insulin resistance in obesity is associated with pathologic remodeling of WAT. This is characterized by hypertrophic growth of existing adipocytes (increase in size), inadequate angiogenesis, chronic metabolic-inflammation, accumulation of extracellular matrix components (fibrosis), and tissue hypoxia8,9. These WAT phenotypes of obesity are associated with hepatic steatosis and insulin resistance, similar to what is observed in the condition of lipodystrophy (absence of functional WAT). In contrast, healthy WAT expansion is observed in the metabolically healthy obese population and is characterized by preferential expansion of protective subcutaneous WAT and depot expansion through adipocyte hyperplasia10. The recruitment of new adipocytes is mediated by de novo adipocyte differentiation from adipocyte precursor cells (APCs) (termed, &#8220;adipogenesis&#8221;). Adipocyte hyperplasia coincides with relatively lower degrees of WAT fibrosis and metabolic inflammation6,11. A multitude of cell types within the WAT microenvironment directly influence the health and expandability of WAT in obesity12. As such, defining the function of the various cell types present in WAT remains a high priority for the field.
Over the past decade, several strategies have been employed to define and isolate native APCs from human and mouse WAT SVF13. Such strategies isolate APCs based on the cell surface expression of common mesenchymal stem/progenitor cell markers using antibody-based cell separation techniques. These approaches include fluorescence-activated cell sorting (FACS), using fluorophore-labelled antibodies, or immunomagnetic bead separation (i.e., chemically modified antibodies). Cell surface proteins targeted for the isolation of APCs include PDGFR&#945;, PDGFR&#946;, CD34, and SCA-1. These approaches have helped enrich for APCs; however, cell populations isolated based on these markers are quite heterogeneous. Very recent single-cell RNA-sequencing (scRNA-seq) studies have highlighted the molecular and functional heterogeneity of stromal cells within the isolated stromal-vascular fraction (SVF) of murine WAT14,15,16,17. From our own scRNA-seq and functional analyses, we have identified and characterized functionally distinct immune-modulating and adipogenic PDGFR&#946;+ perivascular cell subpopulations in the stromal compartment of intra-abdominal WAT in adult mice15. Fibro-inflammatory precursors, or FIPs, represent a prominent subpopulation of PDGFR&#946;+ cells and can be isolated based on LY6C expression (LY6C+ PDGFR&#946;+ cells)15. FIPs lack adipogenic capacity, exert a strong pro-inflammatory response to various stimuli, produce collagen, and secrete anti-adipogenic factors15. The pro-inflammatory and fibrogenic activity of these cells increases in association with obesity in mice, implicating these cells as regulators of WAT remodeling. The LY6C- CD9- PDGFR&#946;+ subpopulation represents adipocyte precursor cells (APCs). These APCs are enriched in the expression of Pparg and other pro-adipogenic genes, and readily differentiate into mature adipocytes in vitro and in vivo15. Here, we provide a detailed protocol for the isolation of these distinct cell populations from intra-abdominal WAT depots of adult mice using FACS, and immunomagnetic bead separation with biotinylated antibodies. This protocol can be used to isolate functionally distinct adipose progenitor subpopulations from multiple intra-abdominal WAT depots of adult male and female mice15. Studying these functionally distinct cell populations in isolation may contribute greatly to our current understanding of the molecular mechanisms that regulate adipogenesis and intra-abdominal adipose tissue remodeling in health and disease.
The protocol below details the isolation of adipose progenitors from murine epididymal WAT; however, the same procedure can be used to isolate corresponding cells from the mesenteric and retroperitoneal WAT depots of both male and female mice15. A detailed protocol on how to identify and isolate these depots in mice can be found in Bagchi et al.18. This protocol has been optimized for the use of mice 6-8 weeks of age. The frequency and differentiation capacity of APCs may decline in association with ageing.

<table>
	<tbody>
		<tr>
			<td>Mechanical Tissue Preparation and SVF Isolation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>40 and 100 &#181;m cell strainers</td>
			<td>Fisher Scientific</td>
			<td>352340/352360</td>
			<td></td>
		</tr>
		<tr>
			<td>1X Phosphate buffered saline (PBS)</td>
			<td>Fisher Scientific</td>
			<td>21040CV</td>
			<td></td>
		</tr>
		<tr>
			<td>5ml polypropylene tubes</td>
			<td>Fisher Scientific</td>
			<td>352053</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Digestion Buffer (for 10mL)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>10 ml HBSS</td>
			<td>Sigma</td>
			<td>H8264</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mg Collagenase D (1 mg/ml final cc.)</td>
			<td>Roche</td>
			<td>11088882001</td>
			<td></td>
		</tr>
		<tr>
			<td>0.15 g BSA (1.5 % final cc.)</td>
			<td>Fisher Scientific</td>
			<td>BP1605-100</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Immunomagnetic separation of APCs and non-APCs</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>5X MojoSort Buffer (MS buffer)</td>
			<td>BioLegend</td>
			<td>480017</td>
			<td></td>
		</tr>
		<tr>
			<td>5 ml MojoSort Magnet (MS magnet)</td>
			<td>BioLegend</td>
			<td>480019</td>
			<td></td>
		</tr>
		<tr>
			<td>100 &#181;L MojoSort Streptavidin Nanobeads</td>
			<td>BioLegend</td>
			<td>480015</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Purity Check and FACS</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>10X Red Blood Cell Lysis Buffer</td>
			<td>eBioscience</td>
			<td>00-4300-54</td>
			<td></td>
		</tr>
		<tr>
			<td>Fc block (Mouse CD16/CD32)</td>
			<td>eBioscience</td>
			<td>553141</td>
			<td></td>
		</tr>
		<tr>
			<td>Antibodies</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Biotin CD45</td>
			<td>BioLegend</td>
			<td>103103</td>
			<td>Concentration: &#8804; 0.25 &#181;g per 10^6 cells 
			Species: Mouse 
			Clone: 30-F11</td>
		</tr>
		<tr>
			<td>Biotin CD31</td>
			<td>BioLegend</td>
			<td>102503</td>
			<td>Concentration: &#8804; 0.25 &#181;g per 10^6 cells 
			Species: Mouse 
			Clone: MEC13.3</td>
		</tr>
		<tr>
			<td>Biotin CD9</td>
			<td>BioLegend</td>
			<td>124803</td>
			<td>Concentration: &#8804; 0.25 &#181;g per 10^6 cells 
			Species: Mouse 
			Clone: MZ3</td>
		</tr>
		<tr>
			<td>Biotin LY6C</td>
			<td>BioLegend</td>
			<td>128003</td>
			<td>Concentration: &#8804; 0.25 &#181;g per 10^6 cells 
			Species: Mouse 
			Clone: HK1.4</td>
		</tr>
		<tr>
			<td>CD31-PerCP/Cy5.5</td>
			<td>BioLegend</td>
			<td>102419</td>
			<td>Concentration: Dilution 1:400 
			Species: Mouse 
			Clone: 390</td>
		</tr>
		<tr>
			<td>CD45-PerCP/Cy5.5</td>
			<td>BioLegend</td>
			<td>103131</td>
			<td>Concentration: Dilution 1:400 
			Species: Mouse 
			Clone: 30-F11</td>
		</tr>
		<tr>
			<td>CD140b PDGFR&#946;-PE</td>
			<td>BioLegend</td>
			<td>136006</td>
			<td>Concentration: Dilution 1:50 
			Species: Mouse 
			Clone: APB5</td>
		</tr>
		<tr>
			<td>LY6C-APC</td>
			<td>BioLegend</td>
			<td>128016</td>
			<td>Concentration: Dilution 1:400 
			Species: Mouse 
			Clone: HK1.4</td>
		</tr>
		<tr>
			<td>CD9-FITC</td>
			<td>BioLegend</td>
			<td>124808</td>
			<td>Concentration: Dilution 1:400 
			Species: Mouse 
			Clone: MZ3</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cell Culture and Differentiation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Gonadal APC Culture media (for 500mL)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>288 mL DMEM with 1 g/L glucose</td>
			<td>Corning</td>
			<td>10-014-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>192 mL MCDB201</td>
			<td>Sigma</td>
			<td>M6770</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mL Fetal bovine serum (FBS)** lot#14E024</td>
			<td>Sigma</td>
			<td>12303C</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL 100% ITS premix</td>
			<td>BD Bioscience</td>
			<td>354352</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL 10 mM L-ascorbic acid-2-2phosphate</td>
			<td>Sigma</td>
			<td>A8960-5G</td>
			<td></td>
		</tr>
		<tr>
			<td>50 &#181;L 100 g/ml FGF-basic</td>
			<td>R&#38;D systems</td>
			<td>3139-FB-025/CF</td>
			<td></td>
		</tr>
		<tr>
			<td>5 mL Pen/Strep</td>
			<td>Corning</td>
			<td>30-001-CI</td>
			<td></td>
		</tr>
		<tr>
			<td>500 &#181;L Gentamycin</td>
			<td>Gibco</td>
			<td>15750-060</td>
			<td></td>
		</tr>
		<tr>
			<td>**NOTE: The adipogenic capacity of primary APCs can vary from lot to lot of commercial FBS. Multiple lots/sources of FBS should be tested.</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation of adipogenic and fibro-inflammatory stromal cell subpopulations from murine intra-abdominal adipose depots

The stromal-vascular fraction (SVF) of white adipose tissue (WAT) is remarkably heterogeneous and consists of numerous cell types that contribute functionally to the expansion and remodeling of WAT in adulthood. A tremendous barrier to studying the implications of this cellular heterogeneity is the inability to readily isolate functionally distinct cell subpopulations from WAT SVF for in vitro and in vivo analyses. Single-cell sequencing technology has recently identified functionally distinct fibro-inflammatory and adipogenic PDGFR&#946;+ perivascular cell subpopulations in intra-abdominal WAT depots of adult mice. Fibro-inflammatory progenitors (termed, &#8220;FIPs&#8221;) are non-adipogenic collagen producing cells that can exert a pro-inflammatory phenotype. PDGFR&#946;+ adipocyte precursor cells (APCs) are highly adipogenic both in vitro and in vivo upon cell transplantation. Here, we describe multiple methods for the isolation of these stromal cell subpopulations from murine intra-abdominal WAT depots. FIPs and APCs can be isolated by fluorescence-activated cell sorting (FACS) or by taking advantage of biotinylated antibody-based immunomagnetic bead technology. Isolated cells can be used for molecular and functional analysis. Studying the functional properties of stromal cell subpopulation in isolation will expand our current knowledge of adipose tissue remodeling under physiological or pathological conditions on the cellular level.

This protocol describes two strategies that allow for the isolation of distinct stromal cell populations from intra-abdominal WAT depots of adult mice. APCs and FIPs can be isolated by FACS (Figure 1) or immunomagnetic bead separation with biotinylated antibodies (Figure 2). Both approaches utilize reagents and antibodies that are all commercially available. Immunomagnetic bead separation leads to the separation of adipogenic from non-adipogenic cells from the g...

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Isolation of Adipogenic and Fibro-Inflammatory Stromal Cell Subpopulations from Murine Intra-Abdominal Adipose Depots

This protocol describes the technical approach to isolate adipogenic and fibro-inflammatory stromal cell subpopulations from murine intra-abdominal white adipose tissue (WAT) depots by fluorescence-activated cell sorting or immunomagnetic bead separation.

The stromal-vascular fraction (SVF) of white adipose tissue (WAT) is remarkably heterogeneous and consists of numerous cell types that contribute ...

The protocol allows investigators to isolate functionally and molecularly distinct subpopulations of perigonadal white adipose tissue stromal cells from mouse models of interest. The advantage of this technique is that all tools and reagents are widely available. Demonstrating the procedure will be Lavanya Vishvanath, a senior laboratory research analyst from Dr.Rana Gupta's laboratory.After stromal vascular cell isolation from gonadal white adipose tissue, or WAT, resuspend the cell pellet in one milliliter of red blood cell lysis buffer for one to two minute incubation at room temperature. Stop the lysis with 10 milliliters of 2%FBS and PBS and filter the cells through a 40 micron cell strainer into a new 50 milliliter centrifuge tube. Collect the cells by centrifugation and resuspend the pellet in 400 to 800 microliters FBS and PBS, supplemented with FC block.After a 10 minute incubation at four degrees Celsius, transfer 400 to 800 microliters of cells to the appropriate number of tubes for fluorescence-conjugated antibody staining and label the cells with the control and experimental antibodies of interest at four degrees Celsius for 15 minutes, protected from light. At the end of the incubation, pellet the cells by centrifugation and wash the cells in 400 microliters of fresh FBS and PBS per tube. After the wash, resuspend the pellets in 400 to 800 microliters of fresh FBS and PBS per tube, and filter the cells through 40 micron filter caps into five milliliter polystyrene round bottom tubes for FACS.Set the compensation and experimental gates to obtain the antigen-presenting cells and fibroinflammatory progenitors. After cell sorting, collect and wash the cells by centrifugation, and resuspend the pellets in 500 microliters of gonadal antigen-presenting cell culture medium per fraction. For immunomagnetic bead separation of the adipogenic and non-adipogenic cell fractions, resuspend the stromal vascular pellet in 10 milliliters of MS buffer and filter the cells through a 40 micron strainer.After counting, collect the cells by centrifugation and resuspend the cells at no more than one times 10 to the eighth cells per milliliter of MS buffer concentration. Next, add no more than 0.25 grams of anti-CD31 and anti-CD45 biotin-conjugated antibody per one times ten to the six cells for a 15 minute incubation on ice. At the end of the incubation, wash the cells in four milliliters of MS buffer by centrifugation, and resuspend the pellet in 100 microliters of fresh MS buffer.Add 10 microliters of streptavidin nanobeads to the cells for a 15 minute incubation on ice, followed by another wash in four milliliters of MS buffer. Resuspend the pellet in 2.5 milliliters of fresh MS buffer and transfer the cells to a five milliliter polypropylene tube. Place the tube onto a magnet for five minutes before decanting the unlabeled cells into a new 15 milliliter centrifuge tube.Repeat the wash two more times as demonstrated, pulling the unlabeled cells after each wash, and collect the endothelial and hematopoietic lineage-depleted cells by centrifugation. Resuspend the pellet in 100 microliters MS buffer and label the cells with no more than 0.25 micrograms of Ly6C and CD-9 antibodies per one times 10 of the sixth cells for 15 minutes on ice. At the end of the incubation, collect the unbound Ly6C negative CD-9 negative adipogenic cells as just demonstrated before collecting the Ly6C positive non-adipogenic cells.Then, collect both cell populations by centrifugation and resuspend the cells in 500 microliters of gonadal antigen-presenting cell culture medium per fraction. To set up cell cultures for differentiation, plate each fraction at four times 10 of the fourth cells per well in concentration in individual wells of a 48 well culture plate and place the plates in the cell culture incubator for seven to 10 days. The adipocyte precursor cells will begin to undergo differentiation into adipocytes as they approach confluence, while the fibroin inflammatory progenitors will be resistant to undergoing adipogenesis.Using this protocol, distinct stromal cell populations can be isolated from intraabdominal WAT depots of adult mice by FACS or immunomagnetic bead separation as demonstrated. With immunomagnetic bead separation, adipogenic and non-adipogenic cells can be isolated from the gonadal WAT stromal vascular fraction. As observed by flow cytometry, 75%of the cells within the adipogenic fraction are Ly6C negative CD-9 negative adipocyte precursor cells, while over 75%of the non-adipogenic fraction, Ly6C positive fibroinflammatory progenitor cells.Adipocyte precursor cells isolated either method differentiate into lipid-containing adipocytes to a high purity within seven to 10 days of plating. In contrast, non adipogenic precursors remain fibroblast-like and do not become adipocytes under the same culture conditions. The protocol works for the isolation of adipogenic and fibroinflammatory stromal cell subpopulations from perigonadal white adipose tissue.Similar cell populations can be found in other adipose depots of mice. However, their selection will rely on the use of different antibodies. The cell populations isolated through FACS and magnetic separation can be used for in vitro assays of cell differentiation or further characterized through gene expression analysis.

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Immunology and Infection

Isolation of Adipose Tissue Immune Cells

The discovery of increased macrophage infiltration in the adipose tissue (AT) of obese rodents and humans has led to an intensification of interest in immune cell contribution to local and systemic insulin resistance. Isolation and quantification of different immune cell populations in lean and obese AT is now a commonly utilized technique in immunometabolism laboratories; yet extreme care must be taken both in stromal vascular cell isolation and in the flow cytometry analysis so that the data obtained is reliable and interpretable. In this video we demonstrate how to mince, digest, and isolate the immune cell-enriched stromal vascular fraction. Subsequently, we show how to antibody label macrophages and T lymphocytes and how to properly gate on them in flow cytometry experiments. Representative flow cytometry plots from low fat-fed lean and high fat-fed obese mice are provided. A critical element of this analysis is the use of antibodies that do not fluoresce in channels where AT macrophages are naturally autofluorescent, as well as the use of proper compensation controls.

Adipose tissue (AT) is a site of intense immune cell activation and interaction. Almost all cells of the immune system are present in AT and their ratios are altered by obesity. Proper isolation, quantification, and characterization of AT immune cell populations are critical for understanding their role in immunometabolic disease.

The discovery of increased macrophage infiltration in  the adipose tissue (AT) of obese rodents and humans has led to an  intensification of interest in ...

Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates

Isolation of microglia from CNS tissue is a powerful investigative tool used to study microglial biology ex vivo. The present method details a procedure for isolation of microglia from neonatal murine cortices by mechanical agitation with a rotary shaker. This microglia isolation method yields highly pure cortical microglia that exhibit morphological and functional characteristics indicative of quiescent microglia in normal, nonpathological conditions in vivo. This procedure also preserves the microglial immunophenotype and biochemical functionality as demonstrated by the induction of morphological changes, nuclear translocation of the p65 subunit of NF-&#954;B (p65), and secretion of the hallmark proinflammatory cytokine, tumor necrosis factor-&#945; (TNF-&#945;), upon lipopolysaccharide (LPS) and Pam3CSK4 (Pam) challenges. Therefore, the present isolation procedure preserves the immunophenotype of both quiescent and activated microglia, providing an experimental method of investigating microglia biology in ex vivo conditions.

One key to successful investigation of microglial biology is the preservation of microglial immunofunction ex vivo during isolation from CNS tissue. Isolating microglia via rotary shaking results in highly pure and immunofunctional cell cultures as assessed by fluorescent imaging, immunocytochemistry, and ELISA following microglia activation with the proinflammatory stimuli lipopolysaccharide (LPS) and Pam3CSK4 (Pam).

Isolation of microglia from CNS tissue is a powerful investigative tool used to study microglial biology ex vivo. The present method details a procedure ...

Isolation of Murine Lymph Node Stromal Cells

Secondary lymphoid organs including lymph nodes are composed of stromal cells that provide a structural environment for homeostasis, activation and differentiation of lymphocytes. Various stromal cell subsets have been identified by the expression of the adhesion molecule CD31 and glycoprotein podoplanin (gp38), T zone reticular cells or fibroblastic reticular cells, lymphatic endothelial cells, blood endothelial cells and FRC-like pericytes within the double negative cell population. For all populations different functions are described including, separation and lining of different compartments, attraction of and interaction with different cell types, filtration of the draining fluidics and contraction of the lymphatic vessels. In the last years, different groups have described an additional role of stromal cells in orchestrating and regulating cytotoxic T cell responses potentially dangerous for the host. 
Lymph nodes are complex structures with many different cell types and therefore require a appropriate procedure for isolation of the desired cell populations. Currently, protocols for the isolation of lymph node stromal cells rely on enzymatic digestion with varying incubation times; however, stromal cells and their surface molecules are sensitive to these enzymes, which results in loss of surface marker expression and cell death. Here a short enzymatic digestion protocol combined with automated mechanical disruption to obtain viable single cells suspension of lymph node stromal cells maintaining their surface molecule expression is proposed.

Isolation of lymph node stromal cells is a multistep procedure including enzymatic digestion and mechanical disaggregation to obtain fibroblastic reticular cells, lymphatic and blood endothelial cells. In the described procedure, a short digestion is combined with automated mechanical disaggregation to minimize surface marker degradation of viable lymph node stromal cells.

Secondary lymphoid organs including lymph nodes are composed of stromal cells that provide a structural environment for homeostasis, activation and ...

Isolation of Leukocytes from the Murine Tissues at the Maternal-Fetal Interface

Immune tolerance in pregnancy requires that the immune system of the mother undergoes distinctive changes in order to accept and nurture the developing fetus. This tolerance is initiated during coitus, established during fecundation and implantation, and maintained throughout pregnancy. Active cellular and molecular mediators of maternal-fetal tolerance are enriched at the site of contact between fetal and maternal tissues, known as the maternal-fetal interface, which includes the placenta and the uterine and decidual tissues. This interface is comprised of stromal cells and infiltrating leukocytes, and their abundance and phenotypic characteristics change over the course of pregnancy. Infiltrating leukocytes at the maternal-fetal interface include neutrophils, macrophages, dendritic cells, mast cells, T cells, B cells, NK cells, and NKT cells that together create the local micro-environment that sustains pregnancy. An imbalance among these cells or any inappropriate alteration in their phenotypes is considered a mechanism of disease in pregnancy. Therefore, the study of leukocytes that infiltrate the maternal-fetal interface is essential in order to elucidate the immune mechanisms that lead to pregnancy-related complications. Described herein is a protocol that uses a combination of gentle mechanical dissociation followed by a robust enzymatic disaggregation with a proteolytic and collagenolytic enzymatic cocktail to isolate the infiltrating leukocytes from the murine tissues at the maternal-fetal interface. This protocol allows for the isolation of high numbers of viable leukocytes (&#62;70%) with sufficiently conserved antigenic and functional properties. Isolated leukocytes can then be analyzed by several techniques, including immunophenotyping, cell sorting, imaging, immunoblotting, mRNA expression, cell culture, and in vitro functional assays such as mixed leukocyte reactions, proliferation, or cytotoxicity assays.

Described herein is a protocol to isolate and analyze the infiltrating leukocytes of tissues at the maternal-fetal interface (uterus, decidua, and placenta) of mice. This protocol maintains the integrity of most cell surface markers and yields enough viable cells for downstream applications including flow cytometry analysis.

Immune tolerance in pregnancy requires that the immune system of the mother undergoes distinctive changes in order to accept and nurture the developing ...

Isolation, Expansion, and Adipogenic Induction of CD34+CD31+ Endothelial Cells from Human Omental and Subcutaneous Adipose Tissue

Obesity is accompanied by an extensive remodeling of adipose tissue primarily via adipocyte hypertrophy. Extreme adipocyte growth results in a poor response to insulin, local hypoxia, and inflammation. By stimulating the differentiation of functional white adipocytes from progenitors, radical hypertrophy of the adipocyte population can be prevented and, consequently, the metabolic health of adipose tissue can be improved along with a reduction of inflammation. Also, by stimulating a differentiation of beige/brown adipocytes, the total body energy expenditure can be increased, resulting in weight loss. This approach could prevent the development of obesity co-morbidities such as type 2 diabetes and cardiovascular disease.
This paper describes the isolation, expansion, and differentiation of white and beige adipocytes from a subset of human adipose tissue endothelial cells that co-express the CD31 and CD34 markers. The method is relatively cheap and is not labor-intensive. It requires access to human adipose tissue and the subcutaneous depot is suitable for sampling. For this protocol, fresh adipose tissue samples from morbidly obese subjects [body mass index (BMI) &#62;35] are collected during bariatric surgery procedures. Using a sequential immunoseparation from the stromal vascular fraction, enough cells are produced from as little as 2&#8211;3 g of fat. These cells can be expanded in culture over 10&#8211;14 days, can be cryopreserved, and retain their adipogenic properties with passaging up to passage 5&#8211;6. The cells are treated for 14 days with an adipogenic cocktail using a combination of human insulin and the PPAR&#947; agonist-rosiglitazone.
This methodology can be used for obtaining proof of concept experiments on molecular mechanisms that drive adipogenic responses in adipose endothelial cells, or for screening new drugs that can enhance the adipogenic response directed either towards white or beige/brown adipocyte differentiation. Using small subcutaneous biopsies, this methodology can be used to screen out non-responder subjects for clinical trials aimed to stimulate beige/brown and white adipocytes for the treatment of obesity and co-morbidities.

The differentiation of white and beige adipocytes from adipose tissue vascular progenitors bears potential for metabolic improvement in obesity. We describe protocols for a CD34+CD31+ endothelial cell isolation from human fat and for a subsequent in vitro expansion and differentiation into white and beige adipocytes. Several downstream applications are discussed.

Obesity is accompanied by an extensive remodeling of adipose tissue primarily via adipocyte hypertrophy. Extreme adipocyte growth results in a poor ...

Simultaneous Study of the Recruitment of Monocyte Subpopulations Under Flow In Vitro

The recruitment of monocytes from the blood to targeted peripheral tissues is critical to the inflammatory process during tissue injury, tumor development and autoimmune diseases. This is facilitated through a process of capture from free flow onto the luminal surface of activated endothelial cells, followed by their adhesion and transendothelial migration (transmigration) into the underlying affected tissue. However, the mechanisms that support the preferential and context-dependent recruitment of monocyte subpopulations are still not fully understood. Therefore, we have developed a method that allows the recruitment of different monocyte subpopulations to be simultaneously visualized and measured under flow. This method, based on time-lapse confocal imaging, allows for the unambiguous distinction between adherent and transmigrated monocytes. Here, we describe how this method can be used to simultaneously study the recruitment cascade of pro-angiogenic and non-angiogenic monocytes in vitro. Furthermore, this method can be extended to study the different steps of recruitment of up to three monocyte populations.

Here, we present an integrated protocol that measures monocyte subpopulation trafficking under flow in vitro by use of specific surface markers and confocal fluorescence microscopy. This protocol can be used to explore sequential recruitment steps as well as to profile other leukocyte subtypes using other specific surface markers.

The recruitment of monocytes from the blood to targeted peripheral tissues is critical to the inflammatory process during tissue injury, tumor development ...

Isolation of Single Intracellular Bacterial Communities Generated from a Murine Model of Urinary Tract Infection for Downstream Single-cell Analysis

In this article, we outline a procedure used to isolate individual intracellular bacterial communities from a mouse that has been experimentally infected in the urinary tract. The protocol can be broadly divided into three sections: the infection, bladder epithelial cell harvesting, and mouth micropipetting to isolate individual infected epithelial cells. The isolated epithelial cell contains viable bacterial cells and is nearly free of contaminating extracellular bacteria, making it ideal for downstream single-cell analysis. The time taken from the start of infection to obtaining a single intracellular bacterial community is about 8 h. This protocol is inexpensive to deploy and uses widely available materials, and we anticipate that it can also be utilized in other infection models to isolate single infected cells from cell mixtures even if those infected cells are rare. However, due to a potential risk in mouth micropipetting, this procedure is not recommended for highly infectious agents.

This protocol describes a simple method of isolating single, infected-bladder epithelial cells from a murine model of urinary tract infection.

In this article, we outline a procedure used to isolate individual intracellular bacterial communities from a mouse that has been experimentally infected ...

Isolation of Lamina Propria Mononuclear Cells from Murine Colon Using Collagenase E

The intestine is the home to the largest number of immune cells in the body. The small and large intestinal immune systems police exposure to exogenous antigens and modulate responses to potent microbially derived immune stimuli. For this reason, the intestine is a major target site of immune dysregulation and inflammation in many diseases including but, not limited to inflammatory bowel diseases such as Crohn&#8217;s disease and ulcerative colitis, graft-versus-host disease (GVHD) after bone marrow transplantation (BMT), and many allergic and infectious conditions. Murine models of gastrointestinal inflammation and colitis are heavily used to study GI complications and to pre-clinically optimize strategies for prevention and treatment. Data gleaned from these models via isolation and phenotypic analysis of immune cells from the intestine is critical to further immune understanding that can be applied to ameliorate gastrointestinal and systemic inflammatory disorders. This report describes a highly effective protocol for the isolation of mononuclear cells (MNC) from the colon using a mixed silica-based density gradient interface. This method reproducibly isolates a significant number of viable leukocytes while minimizing contaminating debris, allowing subsequent immune phenotyping by flow cytometry or other methods.

The goal of this protocol is to isolate mononuclear cells that reside in the lamina propria of the colon by enzymatic digestion of the tissue using collagenase. This protocol allows for the efficient isolation of mononuclear cells resulting in a single cell suspension which in turn can be used for robust immunophenotyping.

The intestine is the home to the largest number of immune cells in the body. The small and large intestinal immune systems police exposure to exogenous ...

Isolation of Macrophage Subsets and Stromal Cells from Human and Mouse Myocardial Specimens

Macrophages represent the most heterogeneous and abundant immune cell populations in the heart and are central in driving inflammation and reparative responses after cardiac injury. How various subsets of macrophages orchestrate the immune responses after cardiac injury is an active area of research. Presented here is a simple protocol that our lab performs routinely, for the extraction of macrophages from mouse and human myocardium specimens obtained from healthy and diseased individuals. Briefly, this protocol involves enzymatic digestion of cardiac tissue to generate a single cell suspension, followed by antibody staining, and flow cytometry. This technique is suitable for functional assays performed on sorted cells as well as bulk and single cell RNA sequencing. A major advantage of this protocol is its simplicity, minimal day to day variation and wide applicability allowing investigation of macrophage heterogeneity across various mouse models and human disease entities.

Presented here is a protocol to isolate various subsets of macrophages and other non-immune cells from human and mouse myocardium by preparing a single cell suspension through enzymatic digestion. Gating schemes for flow cytometry based identification and characterization of isolated macrophages are also presented.

Macrophages represent the most heterogeneous and abundant immune cell populations in the heart and are central in driving inflammation and reparative ...

Isolating Brown Adipocytes from Murine Interscapular Brown Adipose Tissue for Gene and Protein Expression Analysis

Brown adipose tissue (BAT) is responsible for non-shivering thermogenesis in mammals, and brown adipocytes (BAs) are the functional units of BAT. BAs contain both multilocular lipid droplets and abundant mitochondria, and they express uncoupling protein 1 (UCP1). BAs are categorized into two sub-types based on their origin: embryo derived classical BAs (cBAs) and white adipocytes derived BAs. Due to their relatively low density, BAs cannot be isolated from BAT with traditional centrifugation method. In this study, a new method was developed to isolate BAs from mice for gene and protein expression analysis. In this protocol, interscapular BAT from adult mice was digested with Collagenase and Dispase solution, and the dissociated BAs were enriched with 6% iodixanol solution. Isolated BAs were then lysed with Trizol&#160;reagent for simultaneous isolation of RNA, DNA, and protein. After RNA isolation, the organic phase of the lysate was used for protein extraction. Our data showed that 6% iodixanol solution efficiently enriched BAs without interfering with follow-up gene and protein expression studies. Platelet-derived growth factor (PDGF) is a growth factor that regulates the growth and proliferation of mesenchymal cells. Compared to the brown adipose tissue, isolated BAs had significantly higher expression of Pdgfa. In summary, this new method provides a platform for studying the biology of brown adipocytes at a single cell-type level.

This study describes a new method of isolating murine brown adipocytes for gene and protein expression analysis.

Brown adipose tissue (BAT) is responsible for non-shivering thermogenesis in mammals, and brown adipocytes (BAs) are the functional units of BAT. BAs ...