Name: isolation of conditionally immortalized mouse glomerular endothelial cells with fluorescent mitochondria
Uploaded: 2022-09-13T13:30:00
Description: Watch this Scientific Journal Video about Isolation of Conditionally Immortalized Mouse Glomerular Endothelial Cells with Fluorescent Mitochondria at JoVE.com

The authors thank Professor Cijiang He and Dr. Fu Jia for their insights in mice endothelial cell isolation and thank Professor Mone Zaidi for providing the PhAMexcised mice and valuable discussions. The authors would also like to acknowledge the Microscopy CORE at the Icahn School of Medicine at Mount Sinai and staff for the guidance we received. This work was supported by grants from National Institutes of Health grant R01DK097253 and Department of Defense CDMRP grant E01 W81XWH2010836 to I.S.D.

All animal procedures described here were approved by the IACUC at Icahn School of Medicine at Mount Sinai. We used three male mice (H-2Kb-tsA58 transgenic mice with photo-activatable mitochondria [PhAM]) purchased from Jackson lab and kept on a normal chow diet.
1. Working conditions and preparations
<ol>
	<li>Clean the working space inside the laminar flow hood using 70% ethanol and UV-C light.</li>
	<li>Prepare the bead&#39;s washing buffers. Make buffer-1 using 0.1 M sod...

<ol>
	<li>Daehn, I. S., Duffield, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+glomerular+filtration+barrier:+A+structural+target+for+novel+kidney+therapies.">The glomerular filtration barrier: A structural target for novel kidney therapies.</a> Nature Reviews. Drug Discovery. 20 (10), 770-788 (2021).</li><li>Fu, J., Lee, K., Chuang, P. Y., Liu, Z., He, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glomerular+endothelial+cell+injury+and+cross+talk+in+diabetic+kidney+disease.">Glomerular endothelial cell injury and cross talk in diabetic kidney disease.</a> American Journal of Physiology. Renal Physiology. 308 (4), 287-297 (2015).</li><li>Lassen, E., Daehn, I. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+mechanisms+in+early+diabetic+kidney+disease:+Glomerular+endothelial+cell+dysfunction.">Molecular mechanisms in early diabetic kidney disease: Glomerular endothelial cell dysfunction.</a> International Journal of Molecular Sciences. 21 (24), 9456 (2020).</li><li>Haraldsson, B., Jeansson, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glomerular+filtration+barrier.">Glomerular filtration barrier.</a> Current Opinion in Nephrology and Hypertension. 18 (4), 331-335 (2009).</li><li>Yilmaz, O., Afsar, B., Ortiz, A., Kanbay, 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+role+of+endothelial+glycocalyx+in+health+and+disease.">The role of endothelial glycocalyx in health and disease.</a> Clinical Kidney Journal. 12 (5), 611-619 (2019).</li><li>Giacco, F., Brownlee, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxidative+stress+and+diabetic+complications.">Oxidative stress and diabetic complications.</a> Circulation Research. 107 (9), 1058-1070 (2010).</li><li>Daehn, I. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glomerular+endothelial+cell+stress+and+cross-talk+With+podocytes+in+early+[corrected]+diabetic+kidney+disease.">Glomerular endothelial cell stress and cross-talk With podocytes in early [corrected] diabetic kidney disease.</a> Frontiers in Medicine. 5, 76 (2018).</li><li>Satchell, S. 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=Conditionally+immortalized+human+glomerular+endothelial+cells+expressing+fenestrations+in+response+to+VEGF.">Conditionally immortalized human glomerular endothelial cells expressing fenestrations in response to VEGF.</a> Kidney International. 69 (9), 1633-1640 (2006).</li><li>Wieser, 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=hTERT+alone+immortalizes+epithelial+cells+of+renal+proximal+tubules+without+changing+their+functional+characteristics.">hTERT alone immortalizes epithelial cells of renal proximal tubules without changing their functional characteristics.</a> American Journal of Physiology. Renal Physiology. 295 (5), 1365-1375 (2008).</li><li>Jat, P. 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=Direct+derivation+of+conditionally+immortal+cell+lines+from+an+H-2Kb-+tsA58+transgenic+mouse.">Direct derivation of conditionally immortal cell lines from an H-2Kb- tsA58 transgenic mouse.</a> Proceedings of the National Academy of Sciences of the United States of America. 88 (12), 5096-5100 (1991).</li><li>Jat, P. S., Sharp, 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=Cell+lines+established+by+a+temperature-sensitive+simian+virus+40+large-+T-antigen+gene+are+growth+restricted+at+the+nonpermissive+temperature.">Cell lines established by a temperature-sensitive simian virus 40 large- T-antigen gene are growth restricted at the nonpermissive temperature.</a> Molecular and Cellular Biology. 9 (4), 1672-1681 (1989).</li><li>Israel, A., Kimura, A., Fournier, A., Fellous, M., Kourilsky, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interferon+response+sequence+potentiates+activity+of+an+enhancer+in+the+promoter+region+of+a+mouse+H-2+gene.">Interferon response sequence potentiates activity of an enhancer in the promoter region of a mouse H-2 gene.</a> Nature. 322 (6081), 743-746 (1986).</li><li>Mundel, 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=Rearrangements+of+the+cytoskeleton+and+cell+contacts+induce+process+formation+during+differentiation+of+conditionally+immortalized+mouse+podocyte+cell+lines.">Rearrangements of the cytoskeleton and cell contacts induce process formation during differentiation of conditionally immortalized mouse podocyte cell lines.</a> Experimental Cell Research. 236 (1), 248-258 (1997).</li><li>Ohse, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishment+of+conditionally+immortalized+mouse+glomerular+parietal+epithelial+cells+in+culture.">Establishment of conditionally immortalized mouse glomerular parietal epithelial cells in culture.</a> Journal of the American Society of Nephrology. 19 (10), 1879-1890 (2008).</li><li>Rops, A. 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=Isolation+and+characterization+of+conditionally+immortalized+mouse+glomerular+endothelial+cell+lines.">Isolation and characterization of conditionally immortalized mouse glomerular endothelial cell lines.</a> Kidney International. 66 (6), 2193-2201 (2004).</li><li>Pham, A. H., McCaffery, J. M., Chan, D. 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+lines+with+photo-activatable+mitochondria+to+study+mitochondrial+dynamics.">Mouse lines with photo-activatable mitochondria to study mitochondrial dynamics.</a> Genesis. 50 (11), 833-843 (2012).</li><li>Archer, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mitochondrial+dynamics--Mitochondrial+fission+and+fusion+in+human+diseases.">Mitochondrial dynamics--Mitochondrial fission and fusion in human diseases.</a> The New England Journal of Medicine. 369 (23), 2236-2251 (2013).</li><li>Casalena, G. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+diabetic+microenvironment+causes+mitochondrial+oxidative+stress+in+glomerular+endothelial+cells+and+pathological+crosstalk+with+podocytes.">The diabetic microenvironment causes mitochondrial oxidative stress in glomerular endothelial cells and pathological crosstalk with podocytes.</a> Cell Communication and Signaling. 18 (1), 105 (2020).</li><li>Qi, 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=Glomerular+endothelial+mitochondrial+dysfunction+is+essential+and+characteristic+of+diabetic+kidney+disease+susceptibility.">Glomerular endothelial mitochondrial dysfunction is essential and characteristic of diabetic kidney disease susceptibility.</a> Diabetes. 66 (3), 763-778 (2017).</li><li>Akis, N., Madaio, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation,+culture,+and+characterization+of+endothelial+cells+from+mouse+glomeruli.">Isolation, culture, and characterization of endothelial cells from mouse glomeruli.</a> Kidney International. 65 (6), 2223-2227 (2004).</li><li>Schuler, M. 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=Miro1-mediated+mitochondrial+positioning+shapes+intracellular+energy+gradients+required+for+cell+migration.">Miro1-mediated mitochondrial positioning shapes intracellular energy gradients required for cell migration.</a> Molecular Biology of the Cell. 28 (16), 2159-2169 (2017).</li><li>Tang, 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=Mitochondrial+quality+control+in+kidney+injury+and+repair.">Mitochondrial quality control in kidney injury and repair.</a> Nature Reviews. Nephrology. 17 (5), 299-318 (2020).</li><li>Daniel, R., Mengeta, A., Bilodeau, P., Lee, 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=Mitochondria+tether+to+Focal+Adhesions+during+cell+migration+and+regulate+their+size.">Mitochondria tether to Focal Adhesions during cell migration and regulate their size.</a> bioRxiv. , 827998 (2019).</li><li>Dylewski, J. F., 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=Isolation,+purification,+and+conditional+immortalization+of+murine+glomerular+endothelial+cells+of+microvascular+phenotype.">Isolation, purification, and conditional immortalization of murine glomerular endothelial cells of microvascular phenotype.</a> MethodsX. 7, 101048 (2020).</li><li>Drexler, H. G., Uphoff, C. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mycoplasma+contamination+of+cell+cultures:+Incidence,+sources,+effects,+detection,+elimination,+prevention.">Mycoplasma contamination of cell cultures: Incidence, sources, effects, detection, elimination, prevention.</a> Cytotechnology. 39 (2), 75-90 (2002).</li></ol>

Mitochondria are critical for cellular metabolism, homeostasis, and stress responses, and their dysfunction is linked to many diseases, including kidney disease. Mitochondria have a role in the pathologic generation of excessive reactive oxygen species (ROS), the regulation of intracellular calcium levels, cell death pathways, and cytoskeletal dynamics21,22,23.
The isolation of murine GECs is challeng...

The glomerulus is critical for blood filtration by restricting the passage of large molecules through the glomerular filtration barrier1,2. The glomerulus contains four cell types: parietal epithelial cells, podocytes (visceral epithelial cells), glomerular endothelial cells (GEC), and mesangial cells3. The glomerular endothelium is characterized by a unique vascular structure, as per the presence of fenestrae required for large filtration volumes4. The apical surface of the glomerular endothelium is covered with a negatively charged glycocalyx layer and a coat called the endothelial surface layer that creates a space between the endothelium and blood. This structure provides high charge selectivity restricting the passage of negatively charged molecules such as albumin and preventing leukocyte and platelet adhesion5.
GECs are very sensitive to metabolic changes, such as the hyperglycemia associated with the diabetic milieu. Indeed, diabetes leads to increased circulation of noxious substances, the saturation of glucose metabolism pathways, and disturbed cellular redox balance3,6. Moreover, the increase in reactive oxygen species induces mitochondrial dysfunction, which affects endothelial function7.
The overall goal of the current protocol is to isolate immortalized glomerular endothelial cells with fluorescent mitochondrial features. Indeed, the cell culture of primary GECs has a limited proliferative cycle and early senescence8. In addition, the presence of fluorescent mitochondria helps examine fission and fusion events in response to hyperglycemia or any other treatment. As an alternative method, other labs used h-TERT to immortalize cells in vitro9.
The method described here allows for the isolation of conditionally immortalized mitoDendra2 glomerular endothelial cells from 4-6-week-old animals (Figure 1). This detailed protocol describes the use of transgenic mice (H-2Kb-tsA58) harboring the simian virus 40 large tumor antigen (SV40 TAg) gene10,11 for generating thermolabile conditionally immortalized cells. The tsA58 TAg gene product is functional at the permissive temperature of 33 &#176;C under the control of the inducible 5&#39; flanking promoter of the mouse H-2Kb gene, which is increased above basal levels upon exposure to interferon gamma (IFN&#947;), therefore maintaining the conditional proliferation phenotype12. H-2Kb is rapidly degraded at the non-permissive temperature of 37 &#176;C in the absence of IFN&#947;, removing the immortalizing function of the tsA58Tag in cells and allowing the cells to develop a more differentiated phenotype13,14,15. Optional crossing of H-2Kb-tsA58 transgenic mice with PhAM mice, which express a mitochondria-specific (subunit VIII of cytochrome c oxidase) Dendra2-green, allows the live detection of fluorescent mitochondria16. Dendra2 green fluorescence switches to red fluorescence after exposure to a 405 nm laser16. When mitochondria fuse after photo-switching, they form elongated shapes that appear yellow from the exchange of green and yellow material or appear red when they undergo fission7,17. The mitoDendra2-GECs are a great tool for studying the cellular responses of GEC mitochondria to different stimuli.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>100 &#181;m cell strainer</td>
			<td>Fisher</td>
			<td>22-363-549</td>
			<td></td>
		</tr>
		<tr>
			<td>1ml Insulin Syringes</td>
			<td>BD</td>
			<td>329424</td>
			<td></td>
		</tr>
		<tr>
			<td>25G butterfly</td>
			<td>BD</td>
			<td>367298</td>
			<td></td>
		</tr>
		<tr>
			<td>3 mm cutting edge scissors</td>
			<td>F.S.T</td>
			<td>15000-00</td>
			<td></td>
		</tr>
		<tr>
			<td>30ml syringe</td>
			<td>BD Biooscience</td>
			<td>309650</td>
			<td></td>
		</tr>
		<tr>
			<td>40 &#181;m cell strainer</td>
			<td>Fisher</td>
			<td>22-363-547</td>
			<td></td>
		</tr>
		<tr>
			<td>40 &#181;m nylon mesh</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bonn Scissors</td>
			<td>F.S.T</td>
			<td>14184-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin</td>
			<td>Fisher</td>
			<td>BP1600-100</td>
			<td></td>
		</tr>
		<tr>
			<td>CD31</td>
			<td>abcam</td>
			<td>ab7388</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase type I</td>
			<td>Corning</td>
			<td>354236</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase type II</td>
			<td>SIGMA</td>
			<td>C6885</td>
			<td>125CDU/mg</td>
		</tr>
		<tr>
			<td>Collagene type IV</td>
			<td>SIGMA</td>
			<td>C5533-5M</td>
			<td></td>
		</tr>
		<tr>
			<td>Dnase-I</td>
			<td>Qiagen</td>
			<td>79254</td>
			<td></td>
		</tr>
		<tr>
			<td>Dynabeads 450</td>
			<td>Thermofisher Scientific</td>
			<td>14013</td>
			<td></td>
		</tr>
		<tr>
			<td>endothelial cells growth medium</td>
			<td>Lonza</td>
			<td>cc-3156</td>
			<td></td>
		</tr>
		<tr>
			<td>Extra fine graefe forceps</td>
			<td>F.S.T</td>
			<td>11150-10</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Gemini</td>
			<td>100-106</td>
			<td>Heat inactivated</td>
		</tr>
		<tr>
			<td>Fibronectin</td>
			<td>Thermofisher</td>
			<td>33016015</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine forceps</td>
			<td>F.S.T Dumont</td>
			<td>E6511</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>GIBCO</td>
			<td>14065-056</td>
			<td></td>
		</tr>
		<tr>
			<td>IFNg</td>
			<td>Cell Science</td>
			<td>CRI001B</td>
			<td></td>
		</tr>
		<tr>
			<td>Immortomouse</td>
			<td>Jackson laboratory</td>
			<td>32619</td>
			<td>Tg(H2-K1-tsA58)6Kio/LicrmJ</td>
		</tr>
		<tr>
			<td>L-Glutamine 100x</td>
			<td>Thermofisher Scientific</td>
			<td>25030081</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnetic particle concentrator</td>
			<td>Thermofisher Scientific</td>
			<td>12320D</td>
			<td></td>
		</tr>
		<tr>
			<td>mitotracker</td>
			<td>Thermofisher Scientific</td>
			<td>M7512</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS 1X</td>
			<td>Corning</td>
			<td>46-013-CM</td>
			<td></td>
		</tr>
		<tr>
			<td>penecillin streptomycin 100x</td>
			<td>Thermofisher Scientific</td>
			<td>10378016</td>
			<td></td>
		</tr>
		<tr>
			<td>PhaM mice</td>
			<td>Jackson laboratory</td>
			<td>18397</td>
			<td>B6;129S-Gt(ROSA)26Sortm1.1(CAG-COX8A/Dendra2)Dcc/J</td>
		</tr>
		<tr>
			<td>Protease (10 mg/ml)</td>
			<td>SIGMA</td>
			<td>P6911</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI</td>
			<td>GIBCO</td>
			<td>3945</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Pyruvate 100mM</td>
			<td>Thermofisher Scientific</td>
			<td>11360070</td>
			<td></td>
		</tr>
		<tr>
			<td>Standard pattern forceps</td>
			<td>&#160;F.S.T</td>
			<td>11000-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical Scissors - Sharp-Blunt</td>
			<td>F.S.T</td>
			<td>14008-14</td>
			<td></td>
		</tr>
		<tr>
			<td>synaptopodin</td>
			<td>Santa Cruz</td>
			<td>sc-515842</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin 0.05%</td>
			<td>Thermofisher Scientific</td>
			<td>25300054</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolation of conditionally immortalized mouse glomerular endothelial cells with fluorescent mitochondria

Glomerular endothelial cell (GEC) dysfunction can initiate and contribute to glomerular filtration barrier breakdown. Increased mitochondrial oxidative stress has been suggested as a mechanism resulting in GEC dysfunction in the pathogenesis of some glomerular diseases. Historically the isolation of GECs from in vivo models has been notoriously challenging due to difficulties in isolating pure cultures from glomeruli. GECs have complex growth requirements in vitro and a very limited lifespan. Here, we describe the procedure for isolating and culturing conditionally immortalized GECs with fluorescent mitochondria, enabling the tracking of mitochondrial fission and fusion events. GECs were isolated from the kidneys of a double transgenic mouse expressing the thermolabile SV40 TAg (from the Immortomouse), conditionally promoting proliferation and suppressing cell differentiation, and a photo-convertible fluorescent protein (Dendra2) in all mitochondria (from the photo-activatable mitochondria [PhAMexcised] mouse). The stable cell line generated allows for cell differentiation after inactivation of the immortalizing SV40 TAg gene and photo-activation of a subset of mitochondria causing a switch in fluorescence from green to red. The use of mitoDendra2-GECs allows for live imaging of fluorescent mitochondria&#39;s distribution, fusion, and fission events without staining the cells.

In this article, a detailed protocol for the isolation of conditionally immortalized glomerular endothelial cells with stable fluorescent mitochondria (mitoDendra2-GECs) is described (Figure 1). The use of young 6-10-week-old mice is essential to obtain a substantial number of healthy cells. After 3 days of culture, cells start growing slowly from the isolated glomeruli, as shown in Figure 3G. After 7 days, cells are heterogeneous, showing other glomerular cell ...

Watch this Scientific Journal Video about Isolation of Conditionally Immortalized Mouse Glomerular Endothelial Cells with Fluorescent Mitochondria at JoVE.com

Isolation of Conditionally Immortalized Mouse Glomerular Endothelial Cells with Fluorescent Mitochondria

The article describes the method for isolating conditionally immortalized glomerular endothelial cells from the kidneys of transgenic mice expressing the thermolabile simian virus 40 and photo-activatable mitochondria, PhAMexcised. We describe the procedure for glomeruli isolation from whole kidneys using beads, digestion steps, seeding, and culturing of GECs-CD31 positive.

Glomerular endothelial cell (GEC) dysfunction can initiate and contribute to glomerular filtration barrier breakdown. Increased mitochondrial oxidative ...

Immortalized glomerular endothelial cells with stable fluorescent mitochondria are a great tool to examine the effect of different stimuli on mitochondrial structure in vitro. The described method in the current article yields a high number of glomerular endothelial cells. By testing small molecules on a GEC, we could screen for monotherapy for diabetic kidney disease where the GECs are affected.The described method is easy to perform and doesn't require specific equipment. However, it is important to follow the described steps and sterilize the equipment to avoid contamination. To begin, place the perfusion and isolation materials required to isolate kidney glomerular cells on a workspace.Filter the freshly prepared Hanks'Balanced Salt Solution, or HBSS, with a 0.2-micron filter, and keep it under the hood to avoid contamination. Then, mix 200 microliters of magnetic beads with 20 milliliters of HBSS. Prewarm the RPMI with 10%FCS and endothelial cell culture medium in a water bath at 37 degrees Celsius.Then, pre-coat two wells of a six-well plate with two milliliters of 10 micrograms per milliliter collagen IV for 45 minutes at room temperature. Wash the plate twice with PBS to remove the acetic acid used to dilute the collagen. Use the coated plates immediately, or store them at two to eight degrees Celsius for up to four weeks.Clean the surgical instruments and workspace with 70%ethanol. Subsequently, autoclave the surgical instruments for 30 minutes. After opening the abdomen of an anesthetized mouse, insert a butterfly needle into the left ventricle.To inject 100 microliters of the bead solution to expand the blood circulation, carefully break the inferior vena cava below the kidneys with a 19-gauge needle and continue the perfusion of the bead solution. Next, gently remove the fat tissue with tweezers, excise both kidneys with thin surgical scissors C, and put them on a plate with one milliliter of HBSS on ice. Mince the kidney with a sterile scalpel into one-millimeter small pieces.Incubate the minced kidney with one millimeter of freshly prepared collagenase type II for 35 minutes at 37 degrees Celsius with gentle tilting on a horizontal shaker. After digestion, add four milliliters of RPMI with 10%FBS to neutralize the collagenase. Filter the digested tissue through a sterile 100-micron cell strainer into a 50-milliliter tube.Use the bottom of a sterile 1.5-milliliter tube to stir the digested tissue against the strainer, allowing the glomeruli to go through. Rinse the cell strainer with 15 milliliters of HBSS. Then, centrifuge the flow-through at 200 XG for five minutes at room temperature.At this stage, the tube contains three layers. The upper layer contains smaller structures such as tubules, the middle layer is beads with glomeruli, and the bottom layer contains debris. Carefully aspirate the supernatant and the top white layer.Then, resuspend the pellet containing beads bearing the glomeruli and debris in 1.5 milliliters of HBSS and transfer it into a two-milliliter tube. Place the tube in a magnetic concentrator and aspirate the supernatant before washing the beads twice with one milliliter of HBSS. Place 20 microliters of cell suspension onto a slide.Then, observe the slide under a microscope for glomeruli's presence. Next, resuspend the pellet in an endothelial cell growth medium and transfer the suspension to a two-milliliter tube. Add one microliter of interferon gamma for each three milliliters of medium, and place the cells in a six-well plate for incubation at 33 degrees Celsius.After three days of culture, carefully replace the one milliliter medium with a fresh medium. At this stage, the cells are heterogeneous with a mixture of glomerular cells. After seven days, replace the medium with two milliliters of fresh endothelial cell growth medium, supplemented with interferon gamma to start cells'proliferation.After 10 days, when the cells reach 80%confluency, passage them using trypsin and transfer them into a T-25 flask coated with collagen IV.After 21 days of culture, transfer cells to a T-75 flask. Add three milliliters of 0.25%trypsin to a T-75 flask and incubate the cells at 37 degrees Celsius for five minutes. Then, neutralize the trypsin with three milliliters of endothelial growth medium and transfer the suspension to a 15-milliliter tube for centrifugation at 200 XG for five minutes.Aspirate the supernatant and wash the cells in one milliliter of PBS containing 1%BSA, two-millimolar EDTA, 1%penicillin/streptomycin. Again, centrifuge and resuspend the pellet in 200 microliters of CD31 antibody coated beads and 800 microliters of PBS. Incubate the cells for 45 minutes with continuous shaking at 37 degrees Celsius and 5%carbon dioxide.Next, place the tube in the magnetic concentrator and wash the cells four times with PBS containing BSA, EDTA, and penicillin/streptomycin. After the last wash, resuspend the cells in three milliliters of endothelial growth medium, supplemented with interferon gamma. Plate 1.5 milliliters of cells per well in collagen IV coated wells on a six-well plate and culture under permissive conditions at 33 degrees Celsius.After four days, replace 750 microliters of the medium with a fresh endothelial growth medium, supplemented with interferon gamma. After 10 to 14 days of culture, using an epifluorescence microscope with a 488-nanometer filter, observe for growing CD31 positive glomerular endothelial cell, or GECs, colonies that express fluorescent mitochondria. After 21 days, or when the cells have reached 80 to 90%confluency, transfer them into a T-25 flask.Maintain the culture with an RPMI growth medium containing 10%FCS. Alternatively, cells can be cryopreserved. Passage cells using trypsin, as demonstrated earlier.Then, centrifuge the cells and resuspend the pellet in three milliliters of freezing medium. Aliquot the cells in cryo tubes and store them in liquid nitrogen, vapor temperature. This protocol described a method for the isolation of glomerular endothelial cells.From the isolated glomeruli, cells started growing slowly after three days of culture. After seven days, cells appeared heterogeneous and showed other glomerular cell types, such as podocytes, parietal, epithelial, and mesangial cells. After reaching 70 to 80%confluency, other glomerular cells were removed using a positive selection of endothelial cells.The MitoDendra2 GECs expressed CD31 and were negative for podocyte marker, as shown by synaptopodin negative staining. The effect of glucose concentration on the mitochondria structure was examined. Compared to the elongated mitochondria visible in cells under normal glucose, high glucose induced fragmentation or fission of mitochondria, as observed by prominent spheroid shaped mitochondria.Furthermore, a 405-nanometer laser was used to photoconvert a selected subpopulation of mitochondria in a single live MitoDendra2 GEC. A successful photoswitching of mitochondria from green to red in the selected area for normal and high glucose concentration treated cells is shown. This switching allowed witnessing the fusion events in MitoDendra2 GECs.Under normal glucose, yellow merged green and red fluorescence were observed due to mitochondria matrix fusion. In contrast, in the high glucose treated GECs, the mitochondria were mainly fragmented. Placing the cells in one well of six-wells plate with a small volume of growth medium is essential to let the cells attach to the dish.The isolated endothelial cells could be used to perform mitochondrial function and structural studies. The use of immortalized endothelial cells with fluorescent mitochondria features will pave the way toward drug discovery. The small molecules could be tested on the cells, and live imaging is performed to examine their effect on mitochondria function.

isolation-conditionally-immortalized-mouse-glomerular-endothelial

Research

JoVE Journal

Biology

Isolation of Human Umbilical Vein Endothelial Cells (HUVEC)

Angiogenesis is a complex multi-step process, where in response to angiogenic stimuli, new vessels are created from the existing vasculature. These steps include: degradation of the basement membrane, proliferation and migration (sprouting) of endothelial cells (EC) into the extracellular matrix, alignment of EC into cords, lumen formation, anastomosis, and formation of a new basement membrane. Many in vitro assays have been developed to study this process, but most only mimic certain stages of angiogenesis, and morphologically the vessels often do not resemble vessels in vivo. Here we demonstrate an optimized in vitro angiogenesis assay that utilizes human umbilical vein EC and fibroblasts. This model recapitulates all of the key early stages of angiogenesis, and importantly the vessels display patent intercellular lumens surrounded by polarized EC. Vessels can be easily observed by phase-contrast and time-lapse microscopy, and recovered in pure form for downstream applications.

Isolation of Human Umbilical Vein Endothelial Cells HUVEC

This video protocol illustrates the isolation and culture of human umbilical vein endothelial cells (HUVEC) from human umbilical cord. Once isolated these cells can be used for in vitro angiogenesis assays like the Optimized Fibrin Gel Bead Assay also demonstrated by the Hughes lab.

Angiogenesis is a complex multi-step process, where in response to angiogenic stimuli, new vessels are created from the existing vasculature. These steps ...

Isolation of Valvular Endothelial Cells

Heart valves are solely responsible for maintaining unidirectional blood flow through the cardiovascular system. These thin, fibrous tissues are subjected to significant mechanical stresses as they open and close several billion times over a lifespan. The incredible endurance of these tissues is due to the resident valvular endothelial (VEC) and interstitial cells (VIC) that constantly repair and remodel in response to local mechanical and biological signals. Only recently have we begun to understand the unique behaviors of these cells, for which in vitro experimentation has played a key role. Particularly challenging is the isolation and culture of VEC. Special care must be used from the moment the tissue is removed from the host through final plating. Here we present protocols for direct isolation, side specific isolation, culture, and verification of pure populations of VEC. We use enzymatic digestion followed by a gentle swab scraping technique to dislodge only surface cells. These cells are then collected into a tube and centrifuged into a pellet. The pellet is then resuspended and plated into culture flasks pre-coated with collagen I matrix. VEC phenotype is confirmed by contact inhibited growth and the expression of endothelial specific markers such as PECAM1 (CD31), Von Willebrand Factor (vWF), and negative expression of alpha-smooth muscle actin (&alpha;-SMA). The functional characteristics of VEC are associated with high levels of acetylated LDL. Unlike vascular endothelial cells, VEC have the unique capacity to transform into mesenchyme, which normally occurs during embryonic valve formation1. This can also occur during significantly prolonged post confluent in vitro culture, so care should be made to passage at or near confluence. After VEC isolation, pure populations of VIC can then be easily acquired.

We provide a method for isolating and culturing pure populations of heart valve endothelial cells (VEC). VEC can be isolated from either side of the cusp or leaflet and immediately following, underlying interstitial cell (VIC) isolation is straightforward.

Heart valves are solely responsible for maintaining unidirectional blood flow through the cardiovascular system.  These thin, fibrous tissues are ...

Isolation and Culture of Pulmonary Endothelial Cells from Neonatal Mice

Endothelial cells provide a useful research model in many areas of vascular biology. Since its first isolation 1, human umbilical vein endothelial cells (HUVECs) have shown to be convenient, easy to obtain and culture, and thus are the most widely studied endothelial cells. However, for research focused on processes like angiogenesis, permeability or many others, microvascular endothelial cells (ECs) are a much more physiologically relevant model to study 2. Furthermore, ECs isolated from knockout mice provide a useful tool for analysis of protein function ex vivo. Several approaches to isolate and culture microvascular ECs of different origin have been reported to date 3-7, but consistent isolation and culture of pure ECs is still a major technical problem in many laboratories. Here, we provide a step-by-step protocol on a reliable and relatively simple method of isolating and culturing mouse lung endothelial cells (MLECs). In this approach, lung tissue obtained from 6- to 8-day old pups is first cut into pieces, digested with collagenase/dispase (C/D) solution and dispersed mechanically into single-cell suspension. MLECS are purified from cell suspension using positive selection with anti-PECAM-1 antibody conjugated to Dynabeads using a Magnetic Particle Concentrator (MPC). Such purified cells are cultured on gelatin-coated tissue culture (TC) dishes until they become confluent. At that point, cells are further purified using Dynabeads coupled to anti-ICAM-2 antibody. MLECs obtained with this protocol exhibit a cobblestone phenotype, as visualized by phase-contrast light microscopy, and their endothelial phenotype has been confirmed using FACS analysis with anti-VE-cadherin 8 and anti-VEGFR2 9 antibodies and immunofluorescent staining of VE-cadherin. In our hands, this two-step isolation procedure consistently and reliably yields a pure population of MLECs, which can be further cultured. This method will enable researchers to take advantage of the growing number of knockout and transgenic mice to directly correlate in vivo studies with results of in vitro experiments performed on isolated MLECs and thus help to reveal molecular mechanisms of vascular phenotypes observed in vivo.

Here, we describe a protocol for isolation and culture of murine pulmonary endothelial cells. This method comprises mechanic and enzymatic lung tissue dissociation as well as a 2-step purification process using anti-PECAM-1 and anti-ICAM-2 antibodies conjugated to magnetic beads, which produces a pure endothelial cell population of mostly microvascular origin.

Endothelial cells provide a useful research model in many areas of vascular biology. Since its first isolation 1, human umbilical vein endothelial cells ...

Isolation of Embryonic Ventricular Endothelial Cells

Cell culture has greatly enhanced our ability to assess individual populations of cells under myriad culture conditions. While immortalized cell lines offer significant advantages for their ease of use, these cell lines are unavailable for all potential cell types. By isolating primary cells from a specific region of interest, particularly from a transgenic mouse, more nuanced studies can be performed. The basic technique involves dissecting the organ or partial organ of interest (e.g. the heart or a specific region of the heart) and dissociating the organ to single cells. These cells are then incubated with magnetic beads conjugated to an antibody that recognizes the cell type of interest. The cells of interest can then be isolated with the use of a magnet, with a short trypsin incubation dissociating the cells from the beads. These isolated cells can then be cultured and analyzed as desired. This technique was originally designed for adult mouse organs but can be easily scaled down for use with embryonic organs, as demonstrated herein. Because our interest is in the developing coronary vasculature, we wanted to study this population of cells during specific embryonic stages. Thus, the original protocol had to be modified to be compatible with the small size of the embryonic ventricles and the low potential yield of endothelial cells at these developmental stages. Utilizing this scaled-down approach, we have assessed coronary plexus remodeling in transgenic embryonic ventricular endothelial cells.

Primary cell culture is a useful technique for analyzing specific populations of cells, particularly from transgenic mouse embryos at specific developmental stages. Herein, embryonic ventricles are dissected and dissociated, and antibody-conjugated beads recognize and separate out the endothelial cells for further analysis.

Cell culture has greatly enhanced our ability to assess individual populations of cells under myriad culture conditions. While immortalized cell lines ...

Isolation of Microvascular Endothelial Tubes from Mouse Resistance Arteries

The control of blood flow by the resistance vasculature regulates the supply of oxygen and nutrients concomitant with the removal of metabolic by-products, as exemplified by exercising skeletal muscle. Endothelial cells (ECs) line the intima of all resistance vessels and serve a key role in controlling diameter (e.g.&#160;endothelium-dependent vasodilation) and, thereby, the magnitude and distribution of tissue blood flow. The regulation of vascular resistance by ECs is effected by intracellular Ca2+ signaling, which leads to production of diffusible autacoids (e.g.&#160;nitric oxide and arachidonic acid metabolites)1-3 and hyperpolarization4,5 that elicit smooth muscle cell relaxation. Thus understanding the dynamics of endothelial Ca2+ signaling is a key step towards understanding mechanisms governing blood flow control. Isolating endothelial tubes eliminates confounding variables associated with blood in the vessel lumen and with surrounding smooth muscle cells and perivascular nerves, which otherwise influence EC structure and function. Here we present the isolation of endothelial tubes from the superior epigastric artery (SEA) using a protocol optimized for this vessel.
To isolate endothelial tubes from an anesthetized mouse, the SEA is ligated in situ to maintain blood within the vessel lumen (to facilitate visualizing it during dissection), and the entire sheet of abdominal muscle is excised. The SEA is dissected free from surrounding skeletal muscle fibers and connective tissue, blood is flushed from the lumen, and mild enzymatic digestion is performed to enable removal of adventitia, nerves and smooth muscle cells using gentle trituration. These freshly-isolated preparations of intact endothelium retain their native morphology, with individual ECs remaining functionally coupled to one another, able to transfer chemical and electrical signals intercellularly through gap junctions6,7. In addition to providing new insight into calcium signaling and membrane biophysics, these preparations enable molecular studies of gene expression and protein localization within native microvascular endothelium.

We present a preparation for visualizing and manipulating calcium signaling in native, intact microvascular endothelium. Endothelial tubes freshly isolated from mouse resistance arteries supplying skeletal muscle retain in vivo morphology and dynamic signaling within and between neighboring cells. Endothelial tubes can be prepared from microvessels of other tissues and organs.

The control of blood flow by the resistance vasculature regulates the supply of oxygen and nutrients concomitant with the removal of metabolic ...

Isolation of mRNAs Associated with Yeast Mitochondria to Study Mechanisms of Localized Translation

Most of mitochondrial proteins are encoded in the nucleus and need to be imported into the organelle. Import may occur while the protein is synthesized near the mitochondria. Support for this possibility is derived from recent studies, in which many mRNAs encoding mitochondrial proteins were shown to be localized to the mitochondria vicinity. Together with earlier demonstrations of ribosomes&#8217; association with the outer membrane, these results suggest a localized translation process. Such localized translation may improve import efficiency, provide unique regulation sites and minimize cases of ectopic expression. Diverse methods have been used to characterize the factors and elements that mediate localized translation. Standard among these is subcellular fractionation by differential centrifugation. This protocol has the advantage of isolation of mRNAs, ribosomes and proteins in a single procedure. These can then be characterized by various molecular and biochemical methods. Furthermore, transcriptomics and proteomics methods can be applied to the resulting material, thereby allow genome-wide insights. The utilization of yeast as a model organism for such studies has the advantages of speed, costs and simplicity. Furthermore, the advanced genetic tools and available deletion strains facilitate verification of candidate factors.

Many mRNAs encoding mitochondrial proteins are associated with the mitochondria outer membrane. We describe a subcellular fractionation procedure aimed at isolation of yeast mitochondria with its associated mRNAs and ribosomes. This protocol can be applied to cells grown under diverse conditions&#160;in order to reveal mechanisms of mRNA localization and localized translation near the mitochondria.

Most of mitochondrial proteins are encoded in the nucleus and need to be imported into the organelle. Import may occur while the protein is synthesized ...

Isolation of Murine Valve Endothelial Cells

Normal valve structures consist of stratified layers of specialized extracellular matrix (ECM) interspersed with valve interstitial cells (VICs) and surrounded by a monolayer of valve endothelial cells (VECs). VECs play essential roles in establishing the valve structures during embryonic development, and are important for maintaining life-long valve integrity and function. In contrast to a continuous endothelium over the surface of healthy valve leaflets, VEC disruption is commonly observed in malfunctioning valves and is associated with pathological processes that promote valve disease and dysfunction. Despite the clinical relevance, focused studies determining the contribution of VECs to development and disease processes are limited. The isolation of VECs from animal models would allow for cell-specific experimentation. VECs have been isolated from large animal adult models but due to their small population size, fragileness, and lack of specific markers, no reports of VEC isolations in embryos or adult small animal models have been reported. Here we describe a novel method that allows for the direct isolation of VECs from mice at embryonic and adult stages. Utilizing the Tie2-GFP reporter model that labels all endothelial cells with Green Fluorescent Protein (GFP), we have been successful in isolating GFP-positive (and negative) cells from the semilunar and atrioventricular valve regions using fluorescence activated cell sorting (FACS). Isolated GFP-positive VECs are enriched for endothelial markers, including CD31 and von Willebrand Factor (vWF), and retain endothelial cell expression when cultured; while, GFP-negative cells exhibit molecular profiles and cell shapes consistent with VIC phenotypes. The ability to isolate embryonic and adult murine VECs allows for previously unattainable molecular and functional studies to be carried out on a specific valve cell population, which will greatly improve our understanding of valve development and disease mechanisms.

The ability to isolate heart valve endothelial cells (VECs) is critical for understanding mechanisms of valve development, maintenance, and disease. Here we describe the isolation of VECs from embryonic and adult Tie2-GFP mice using FACS that will allow for studies determining the contribution of VECs in developmental and disease processes.

Normal valve structures consist of stratified layers of specialized extracellular matrix (ECM) interspersed with valve interstitial cells (VICs) and ...

Isolation and Functional Analysis of Mitochondria from Cultured Cells and Mouse Tissue

Comparison between two or more distinct groups, such as healthy vs. disease, is necessary to determine cellular status. Mitochondria are at the nexus of cell heath due to their role in both cell metabolism and energy production as well as control of apoptosis. Therefore, direct evaluation of isolated mitochondria and mitochondrial perturbation offers the ability to determine if organelle-specific (dys)function is occurring. The methods described in this protocol include isolation of intact, functional mitochondria from HEK cultured cells and mouse liver and spinal cord, but can be easily adapted for use with other cultured cells or animal tissues. Mitochondrial function assessed by TMRE and the use of common mitochondrial uncouplers and inhibitors in conjunction with a fluorescent plate reader allow this protocol not only to be versatile and accessible to most research laboratories, but also offers high throughput.

Comparison of mitochondrial membrane potential between samples yields valuable information about cellular status. Detailed steps for isolating mitochondria and assessing response to inhibitors and uncouplers using fluorescence are described. The method and utility of this protocol are illustrated by use of a cell culture and animal model of cellular stress.

Comparison between two or more distinct groups, such as healthy vs. disease, is necessary to determine cellular status. Mitochondria are at the nexus of ...

Isolation and Primary Culture of Mouse Aortic Endothelial Cells

The vascular endothelium is essential to normal vascular homeostasis. Its dysfunction participates in various cardiovascular disorders. The mouse is an important model for cardiovascular disease research. This study demonstrates a simple method to isolate and culture endothelial cells from the mouse aorta without any special equipment. To isolate endothelial cells, the thoracic aorta is quickly removed from the mouse body, and the attached adipose tissue and connective tissue are removed from the aorta. The aorta is cut into 1 mm rings. Each aortic ring is opened and seeded onto a growth factor reduced matrix with the endothelium facing down. The segments are cultured in endothelial cell growth medium for about 4 days. The endothelial sprouting starts as early as day 2. The segments are then removed and the cells are cultured continually until they reach confluence. The endothelial cells are harvested using neutral proteinase and cultured in endothelial cell growth medium for another two passages before being used for experiments. Immunofluorescence staining indicated that after the second passage the majority of cells were double positive for Dil-ac-LDL uptake, Lectin binding, and CD31 staining, the typical characteristics of endothelial cells. It is suggested that cells at the second to third passages are suitable for in vitro and in vivo experiments to study the endothelial biology. Our protocol provides an effective means of identifying specific cellular and molecular mechanisms in endothelial cell physiopathology.

The vascular endothelial cells play a significant role in many important cardiovascular disorders. This article describes a simple method to isolate and expand endothelial cells from the mouse aorta without using any special equipment. Our protocol provides an effective means of identifying mechanisms in endothelial cell physiopathology.

The vascular endothelium is essential to normal vascular homeostasis. Its dysfunction participates in various cardiovascular disorders. The mouse is an ...

Isolation of Mouse Coronary Endothelial Cells

Endothelial cells line the inner wall of blood vessels and play an important role in the regulation of vascular tone, vascular permeability, and new vascular formation. Endothelial cell dysfunction is implicated in the development and progression of many cardiovascular diseases including ischemic heart disease. To examine the function and characterization of coronary endothelial cells, cell isolation is the first step and it requires high purity and quantity to conduct subsequent experiments. This protocol describes an efficient method to isolate adult mouse coronary endothelial cells. The mouse heart is dissected and minced into small pieces. After the digestion of the heart using dispase and collagenase II, cells are washed&#160;and incubated with magnetic beads which are conjugated with anti-CD31 antibody. The beads with endothelial cells are washed several times and are ready to use in various applications, including imaging and molecular biological experiments. Efficient isolation yields approximately 104 cells per one heart with over 90% purity.

This protocol is prepared to share our method of isolating mouse coronary endothelial cells for the purpose of imaging or to conduct molecular biological experiments.

Endothelial cells line the inner wall of blood vessels and play an important role in the regulation of vascular tone, vascular permeability, and new ...