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>

Authors have no competing financial interests to declare.

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

1.9K ビュー.  The Icahn School of Medicine at Mount Sinai. 安定した蛍光ミトコンドリアを有する不死化糸球体内皮細胞は、in vitroでミトコンドリア構造に対するさまざまな刺激の影響を調べるための優れたツールです。本論文に記載されている方法は、多数の糸球体内皮細胞を生じる。GECで低分子を試験することにより、GECが罹患している糖尿病性腎疾患の単剤療法をスクリーニングすることができます。説明されている?...