Name: working with auditory hei-oc1 cells
Uploaded: 2016-09-03T14:00:00
Description: Watch this Scientific Journal Video about Working with Auditory HEI-OC1 Cells at JoVE.com

This work was supported by NIH Grants R01-DC010146 and R01-DC010397. Its content is solely the responsibility of the authors and does not necessarily represent the official view of the National Institutes of Health.

1. Cell Culture
Note: All cell culturing protocols must be performed using proper cell culture techniques (for reference see the first 3 Chapters of Cell Biology: A Laboratory Handbook, Volume I 10). HEI-OC1 cells do not require any additional coating or treatment of the cell culture dishes for proper adherence and growth. Very important: do not use glassware dishes for cell culture purposes; the phenotype and biological response of the cells to pharmacological drugs will change (G Ka...

<ol>
	<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+immortall+cell+lines+from+an+H-2Kb-tsA58+transgenic+mouse.">Direct derivation of conditionally immortall cell lines from an H-2Kb-tsA58 transgenic mouse.</a> Proc. Natl. Acad. Sci. 88, 5096-5100 (1991).</li><li>Kalinec, G. M., Webster, P., Lim, D. J., Kalinec, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+cochlear+cell+line+as+an+in+vitro+system+for+drug+ototoxicity+screening.">A cochlear cell line as an in vitro system for drug ototoxicity screening.</a> Audiol. Neurootol. 8, 177-189 (2003).</li><li>Devarajan, 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=Cisplatin-induced+apoptosis+in+auditory+cells:+role+of+death+receptor+and+mitochondrial+pathways.">Cisplatin-induced apoptosis in auditory cells: role of death receptor and mitochondrial pathways.</a> Hear Res. 174, 45-54 (2002).</li><li>Chen, F. Q., Hill, K., Guan, Y. J., Schacht, J., Sha, S. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activation+of+apoptotic+pathways+in+the+absence+of+cell+death+in+an+inner-ear+immortomouse+cell+line.">Activation of apoptotic pathways in the absence of cell death in an inner-ear immortomouse cell line.</a> Hear Res. 284, 33-41 (2012).</li><li>Hayashi, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+autophagy+pathway+maintained+signaling+crosstalk+with+the+Keap1-Nrf2+system+through+p62+in+auditory+cells+under+oxidative+stress.">The autophagy pathway maintained signaling crosstalk with the Keap1-Nrf2 system through p62 in auditory cells under oxidative stress.</a> Cell Signal. 27, 382-393 (2015).</li><li>Tsuchihashi, N. 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=Autophagy+through+4EBP1+and+AMPK+regulates+oxidative+stress-induced+premature+senescence+in+auditory+cells.">Autophagy through 4EBP1 and AMPK regulates oxidative stress-induced premature senescence in auditory cells.</a> Oncotarget. 6, 3644-3655 (2015).</li><li>Youn, C. K., Kim, J., Park, J. H., Do, N. Y., Cho, S. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+autophagy+in+cisplatin-induced+ototoxicity.">Role of autophagy in cisplatin-induced ototoxicity.</a> Int J Pediatr Otorhinolaryngol. 79, 1814-1819 (2015).</li><li>Kalinec, G., Thein, P., Park, C., Kalinec, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HEI-OC1+cells+as+a+model+for+investigating+drug+cytotoxicity.">HEI-OC1 cells as a model for investigating drug cytotoxicity.</a> Hear Res. 335, 105-117 (2016).</li><li>Park, C., Thein, P., Kalinec, G., Kalinec, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=HEI-OC1+cells+as+a+model+for+investigating+prestin+function.">HEI-OC1 cells as a model for investigating prestin function.</a> Hear Res. 335, 9-17 (2016).</li><li>Celis, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Cell Biology: A Laboratory Handbook. 1, (2006).</li><li>Bertolaso, 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=Apoptosis+in+the+OC-k3+immortalized+cell+line+treated+with+different+agents.">Apoptosis in the OC-k3 immortalized cell line treated with different agents.</a> Audiology. 40, 327-335 (2001).</li><li>Kalinec, F., Kalinec, G., Boukhvalova, M., Kachar, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Establishment+and+characterization+of+conditionally+immortalized+organ+of+corti+cell+lines.">Establishment and characterization of conditionally immortalized organ of corti cell lines.</a> Cell Biol Int. 23, 175-184 (1999).</li><li>Belyantseva, I., Kalinec, G. M., Kalinec, F., Kachar, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+differentiation+of+two+immortalized+cell+lines+derived+from+the+stria+vascularis+of+a+transgenic+mouse.">In vitro differentiation of two immortalized cell lines derived from the stria vascularis of a transgenic mouse.</a> 21st Midwinter Meeting Association for Research in Otolaryngology. 620a, (1998).</li><li>Gratton, M. A., Meehan, D. T., Smyth, B. J., Cosgrove, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strial+marginal+cells+play+a+role+in+basement+membrane+homeostasis:+in+vitro+and+in+vivo+evidence.">Strial marginal cells play a role in basement membrane homeostasis: in vitro and in vivo evidence.</a> Hear Res. 163, 27-36 (2002).</li><li>Debacq-Chainiaux, F., Erusalimsky, J. D., Campisi, J., Toussaint, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protocols+to+detect+senescence-associated+beta-galactosidase+(SA-betagal)+activity,+a+biomarker+of+senescent+cells+in+culture+and+in+vivo.">Protocols to detect senescence-associated beta-galactosidase (SA-betagal) activity, a biomarker of senescent cells in culture and in vivo.</a> Nat Protoc. 4, 1798-1806 (2009).</li><li>Santos-Sacchi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reversible+inhibition+of+voltage-dependent+outer+hair+cell+motility+and+capacitance.">Reversible inhibition of voltage-dependent outer hair cell motility and capacitance.</a> J. Neurosci. 11, 3096-3110 (1991).</li><li>Fink, S. L., Cookson, B. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Apoptosis,+pyroptosis,+and+necrosis:+mechanistic+description+of+dead+and+dying+eukaryotic+cells.">Apoptosis, pyroptosis, and necrosis: mechanistic description of dead and dying eukaryotic cells.</a> Infect Immun. 73, 1907-1916 (2005).</li><li>Majno, G., Joris, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Apoptosis,+oncosis,+and+necrosis.+An+overview+of+cell+death.">Apoptosis, oncosis, and necrosis. An overview of cell death.</a> Am J Pathol. 146, 3-15 (1995).</li><li>Vanden Berghe, T., Linkermann, A., Jouan-Lanhouet, S., Walczak, H., Vandenabeele, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulated+necrosis:+the+expanding+network+of+non-apoptotic+cell+death+pathways.">Regulated necrosis: the expanding network of non-apoptotic cell death pathways.</a> Nat Rev Mol Cell Biol. 15, 135-147 (2014).</li><li>Sun, L., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+kind+of+cell+suicide:+mechanisms+and+functions+of+programmed+necrosis.">A new kind of cell suicide: mechanisms and functions of programmed necrosis.</a> Trends Biochem Sci. 39, 587-593 (2014).</li><li>Chan, F. K., Luz, N. F., Moriwaki, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Programmed+necrosis+in+the+cross+talk+of+cell+death+and+inflammation.">Programmed necrosis in the cross talk of cell death and inflammation.</a> Annu Rev Immunol. 33, 79-106 (2015).</li><li>Vercammen, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dual+signaling+of+the+Fas+receptor:+initiation+of+both+apoptotic+and+necrotic+cell+death+pathways.">Dual signaling of the Fas receptor: initiation of both apoptotic and necrotic cell death pathways.</a> J Exp Med. 188, 919-930 (1998).</li><li>Campisi, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Aging,+cellular+senescence,+and+cancer.">Aging, cellular senescence, and cancer.</a> Annu Rev Physiol. 75, 685-705 (2013).</li><li>Bian, S., Koo, B. W., Kelleher, S., Santos-Sacchi, J., Navaratnam, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+highly+expressing+Tet-inducible+cell+line+recapitulates+in+situ+developmental+changes+in+prestin's+Boltzmann+characteristics+and+reveals+early+maturational+events.">A highly expressing Tet-inducible cell line recapitulates in situ developmental changes in prestin's Boltzmann characteristics and reveals early maturational events.</a> Am J Physiol Cell Physiol. 299, C828-C835 (2010).</li><li>Abe, 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=Developmental+expression+of+the+outer+hair+cell+motor+prestin+in+the+mouse.">Developmental expression of the outer hair cell motor prestin in the mouse.</a> J Membr Biol. 215, 49-56 (2007).</li><li>Oliver, D., Fakler, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Expression+density+and+functional+characteristics+of+the+outer+hair+cell+motor+protein+are+regulated+during+postnatal+development+in+rat.">Expression density and functional characteristics of the outer hair cell motor protein are regulated during postnatal development in rat.</a> J Physiol. 519 Pt 3, 791-800 (1999).</li><li>Tsunoo, M., Perlman, H. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cochlear+Oxygen+Tension:+Relation+to+Blood+Flow+and+Function.">Cochlear Oxygen Tension: Relation to Blood Flow and Function.</a> Acta Otolaryngol. 59, 437-450 (1965).</li></ol>

In this report we describe how to culture HEI-OC1 cells and use them to evaluate mechanisms of drug-induced cytotoxicity and to investigate functional properties of prestin, the molecular motor of cochlear OHCs. The technical procedures, however, are general enough to be easily adapted to different studies.
All the protocols described here require the correct use of well-established cell culture techniques 10. Just like with any other cell line, working with HEI-OC1 cells requires a...

House Ear Institute-Organ of Corti 1 (HEI-OC1) cells are derived from the auditory organ of a transgenic mouse 1,2. Incubation of any cell from this transgenic mouse at 33 &#176;C/10% CO2 (permissive conditions) induces expression of an immortalizing gene that triggers de-differentiation and accelerated proliferation; moving the cells to 39 &#176;C/5% CO2 (non-permissive conditions) lead to decreased proliferation, differentiation and, at least in the case of HEI-OC1, cell death 2,3.
HEI-OC1 cells were cloned and characterized in our laboratory over a decade ago, and initial studies indicated that they express specific markers of cochlear hair cells, such as prestin, myosin 7a, Atoh1, BDNF, calbindin and calmodulin, but also markers of supporting cells like connexin 26 and fibroblast growth factor receptor (FGF-R) 2. Therefore, it was suggested that HEI-OC1 could represent a common progenitor for sensory and supporting cells of the organ of Corti 2. Parallel studies provided strong evidence that archetypal ototoxic drugs like cisplatin, gentamicin and streptomycin induced caspase-3 activation in these cells, while drugs considered non-ototoxic, like penicillin, did not 2,3. Therefore, this cell line was proposed as an in vitro system to investigate the cellular and molecular mechanisms involved in ototoxicity and for screening of the potential ototoxicity or otoprotective properties of new pharmacological drugs. It is estimated that HEI-OC1 cells have been used in more than one hundred and fifty studies published in the last ten years.
Whereas looking at the potential pro-apoptotic effect of different drugs was the major goal of most of the studies involving this cell line, other important cell processes like autophagy and senescence have just started to be investigated in HEI-OC1 cells4-7. In a recent study from our laboratory 8, we used HEI-OC1 cells to collect a comprehensive set of data about cell death, survival, proliferation, senescence and autophagy induced by different pharmacological drugs frequently used in the clinic. We also compared some of the responses of HEI-OC1 cells with those from HEK-293 (human embryonic kidney cells) and HeLa (human epithelial cells) receiving identical treatment. Our results indicated that HEI-OC1 cells respond to the each drug in a characteristic way, with a distinctive dose- and time-dependent sensitivity to at least one of the mechanisms under study. We also emphasized in that study that a correct interpretation of the experimental results will require performing parallel studies with more than one technique 8.
In a different study we investigated the use of HEI-OC1 cells to evaluate the functional response of prestin, the motor protein of cochlear outer hair cells (OHCs) 9. We reported flow cytometry and confocal laser scanning microscopy studies on the pattern of prestin expression, as well as nonlinear capacitance (NLC) and whole cell-patch clamping studies in HEI-OC1 cells cultured at permissive (P-HEI-OC1) and non-permissive (NP-HEI-OC1) conditions. Our results indicated that both total prestin expression and plasma membrane localization increase in a time-dependent manner in NP-HEI-OC1 cells. Interestingly, we also found that the increase in prestin localization at the plasma membrane of NP-HEI-OC1 cells correlated with a decrease in Na+K+ATPase, which translocated from the plasma membrane to the cytoplasm without significant changes in total cell expression. In addition, we demonstrated that P-HEI-OC1 cells have a robust NLC associated to prestin motor function, which decreased when the density of prestin molecules present at the plasma membrane increased. Altogether, these results strongly support the usefulness of HEI-OC1 cells to investigate auditory proteins.
In this video article we describe how to culture HEI-OC1 cells, why it is convenient to use cells growing at permissive conditions (P-HEI-OC1) for cytotoxicity studies, how to evaluate the mechanism/s of drug-induced cytotoxicity and how to perform electrophysiological studies (e.g., patch-clamp, non-linear capacitance (NLC)) to investigate functional properties of prestin, the molecular motor of cochlear OHCs.

<table border="0" cellpadding="0" cellspacing="0" width="1447">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:905px;">HEI-OC1 cells</td>
			<td style="width:143px;"></td>
			<td style="width:139px;"></td>
			<td style="width:260px;">ALL THE ASSAY KITS, EQUIPMENTS&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Class II Biological Safety cabinet</td>
			<td>The Baker Company</td>
			<td>Sterilgard III</td>
			<td>AND COMPANIES INDICATED IN THE</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Refrigerated centrifuge</td>
			<td>Eppendorf</td>
			<td>5810R</td>
			<td>PREVIOUS 2 COLUMNS ARE ONLY</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Inverted microscope</td>
			<td>Zeiss</td>
			<td>Axiovert 25</td>
			<td>EXAMPLES, AND ANY OTHER SIMILAR</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Waterbath</td>
			<td>Stovall</td>
			<td>HWB115</td>
			<td>PRODUCT COULD BE USED.</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cell counter</td>
			<td>Nexcelom</td>
			<td>Cellometer Auto T4</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Two (2) Cell incubators, one at 33&#176;C/10% CO2 and other at 39&#176;C/5% CO2</td>
			<td>Forma Scientific</td>
			<td>3110</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cell culture dishes, PS, 100 x 20 mm with vents</td>
			<td>Greinier Bio-One</td>
			<td>664-160</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cell culture dishes , PS,&#160; 60 x 15 mm with vents&#160;</td>
			<td>Greiner Bio-One</td>
			<td>628160</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cellstar tissue culture flasks&#160; 250 mL</td>
			<td>Greiner Bio-One</td>
			<td>658-175</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cellstar tissue cultur&#160; flasks 550 mL</td>
			<td>Greiner Bio-One</td>
			<td>660-175</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;6 well cell culture plate, with lid-Cellstar</td>
			<td>Greiner Bio-One</td>
			<td>657-160</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Microtest Tissue culture plate, 96 well,flat bottom with lid</td>
			<td>Becton Dickinson</td>
			<td>353072</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Micro-Assay-Plate, Chimmey, 96-well white,clear botton</td>
			<td>Greiner Bio-One</td>
			<td>655098</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">50 ml Polypropylene conical tube with cap Cellstars</td>
			<td>Becton Dickinson&#160;</td>
			<td>352070</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">15 ml Polypropylene conical tubes with cap-Cellstars</td>
			<td>Greiner Bio-One</td>
			<td>188-271</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">PBS pH 7.4 (1X)&#160;</td>
			<td>Life Technologies</td>
			<td>10010-023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dulbecco&#8217;s Modified Eagle&#8217;s Medium (DMEM)</td>
			<td>Life Technologies</td>
			<td>11965-084</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fetal bovine serum (FBS)&#160;</td>
			<td>Hyclone</td>
			<td>SH10073.1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Leibovitz&#39;s L-15 Medium, no phenol red</td>
			<td>Gibco/Invitrogen</td>
			<td>21083-027</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Trypsin, 0.25%&#160;</td>
			<td>Life Technologies</td>
			<td>25200-056</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TACS MTT Cell Proliferation Assay Kit</td>
			<td>Trevigen</td>
			<td>4890-25-K</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Caspase-Glo 3/7 Assay&#160; kit</td>
			<td>Promega</td>
			<td style="width:139px;">&#160; G8091&#160;</td>
			<td style="width:260px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">BrdU Cell Proliferation Assay Kit&#160;</td>
			<td>Cell Signaling</td>
			<td>6813</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Non-enzymatic cell dissociation solution&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>C5789</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cell-Tox Green Cytotoxicity Assay Kit</td>
			<td>Promega</td>
			<td style="width:139px;">&#160; G8741&#160;</td>
			<td style="width:260px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">FACSAriaIII instrument&#160;</td>
			<td>BD Biosciences</td>
			<td>&#160;FACSAriaIII</td>
			<td>With 488 nm excitation (blue laser)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Digital Blot Scanner</td>
			<td>LI-COR</td>
			<td>C-DiGit</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Electrophoresis and Blotting Unit</td>
			<td>Hoefer</td>
			<td>SE300 miniVE</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Spectra Max 5 Plate Reader with Soft Max Pro 5.2 Software</td>
			<td>Molecular Devices</td>
			<td>SpectraMax 5</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Patch-clamp amplifier</td>
			<td>HEKA</td>
			<td>EPC-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Puller for preparing patch electrodes</td>
			<td>Sutter Instruments</td>
			<td>P-97</td>
			<td></td>
		</tr>
	</tbody>
</table>

working with auditory hei-oc1 cells

HEI-OC1 is one of the few mouse auditory cell lines available for research purposes. Originally proposed as an in vitro system for screening of ototoxic drugs, these cells have been used to investigate drug-activated apoptotic pathways, autophagy, senescence, mechanism of cell protection, inflammatory responses, cell differentiation, genetic and epigenetic effects of pharmacological drugs, effects of hypoxia, oxidative and endoplasmic reticulum stress, and expression of molecular channels and receptors. Among other several important markers of cochlear hair cells, HEI-OC1 cells endogenously express prestin, the paradigmatic motor protein of outer hair cells. Thus, they can be very useful to elucidate novel functional aspects of this important auditory protein. HEI-OC1 cells are very robust, and their culture usually does not present big complications. However, they require some special conditions such as avoiding the use of common anti-bacterial cocktails containing streptomycin or other antibiotics as well as incubation at 33 &#176;C to stimulate cell proliferation and incubation at 39 &#176;C to trigger cell differentiation. Here, we describe how to culture HEI-OC1 cells and how to use them in some typical assays, such as cell proliferation, viability, death, autophagy and senescence, as well as how to perform patch-clamp and non-linear capacitance measurements.

In a couple of recent publications we reported a comprehensive set of studies aimed at evaluating the response of HEI-OC1 cells to several commonly used pharmacological drugs as well as investigating prestin function 8,9. In these studies we made use of all the protocols described in the previous sections.
One of the results of these previous studies was that HEI-OC1 cells cultured at non-permissive conditions (39 &#1...

Watch this Scientific Journal Video about Working with Auditory HEI-OC1 Cells at JoVE.com

Working with Auditory HEI-OC1 Cells

House Ear Institute-Organ of Corti 1 (HEI-OC1) is one of the few mouse auditory cell lines currently available for research purposes. This protocol describes how to work with HEI-OC1 cells to investigate the cytotoxic effects of pharmacological drugs as well as functional properties of inner ear proteins.

HEI-OC1 is one of the few mouse auditory cell lines available for research purposes. Originally proposed as an in vitro system for screening of ototoxic ...

The overall goal of this protocol is to describe the basic procedures to work with HEI-OC1 cells, which can be used to study the effects of pharmacological drugs on auditory cells, and assist in the functional characterization of the motor protein prestin. HEI-OC1 cells are used by many researchers around the world in different experiments with different goals and using different techniques. Hopefully, the procedures described here will provide a common base to make these studies comparable.Of course, these experimental procedures may be further improved. But the differences with those described here could be key to understand and explain possibly contradictory results. In this demonstration we will describe how to work with HEI-OC1 cells starting from a frozen aliquot to having samples ready to perform different studies with widely available techniques.To begin this procedure remove a vial of cryopreserved HEI-OC1 cells from liquid nitrogen and place it in a water bath at 37 degrees Celsius. Submerge only the lower half of the vial and allow it to thaw until only a small amount of ice remains in the vial. In a biological safety cabinet, wipe the outside of the vial with 70%alcohol.Then, pipette the cells from the vial and deliver the entire volume drop by drop, slowly, into a 15 milliliter conical tube containing 10 milliliters of prewarmed growth medium such as DMEM supplemented with 10%FBS. Next, remove the DMSO by centrifuging the tube for five minutes. After five minutes, discard the supernatant and resuspend the cells in nine milliliters of fresh growth medium.Disaggregate the clumps or sheets of cells by fluxing and refluxing the suspended cells between the pipette and the medium three to four times with the tip of the pipette touching the bottom of the tube. Then, place the total volume of cells suspended in growth medium in a 100 millimeter diameter untreated plastic cell culture dish. Incubate the cells at 33 degrees Celsius with 10%CO2.In this step, remove the old medium and wash the cells with two milliliters of PBS. Then, cover the cell monolayer with 0.25%trypsin. Examine the cells using an inverted microscope when 40%of them have been detached.If necessary, gently rock the culture dish to release any remaining attached cells Resuspend the cells and remove the trypsin by centrifuging the tube for five minutes. Afterward, discard the supernatant and resuspend the cells in nine milliliters of fresh growth medium. Next, disaggregate the clumps or sheets of cells by fluxing and refluxing the suspended cells between the pipette and the medium, three to four times with the tip of the pipette touching the bottom of the tube.Proceed to seed the cells in 100 millimeter diameter cell culture dishes. Incubate them at 33 degrees Celsius with 10%CO2 and divide them as many times as necessary for the planned experiments, or for generating a new stock. For differentiation, incubate HEI-OC1 cells at the permissive conditions until they reach about 80%confluence.Then, incubate the cells at 39 degrees Celsius with 5%CO2 for two to three weeks and change the medium every other day to remove dead cells. Begin this procedure by counting the cells using either an automatic cell counter or a hemocytometer and adjust the cell concentration to the required value. Next, seed the cells in a 96 well clear flat bottom plate, a white walled 96 well plate, or a six well plate.If required by the particular assay, incubate the cells overnight for substrate attachment before treating them with the drugs of interest. Then, measure the outcome of the treatment by flow cytometry or another adequate technique. To harvest the cells, wash them twice with 10 milliliters of calcium-and magnesium-free PBS.Add two milliliters of the enzyme-free detacher solution and incubate the cells for three minutes at 37 degrees Celsius with 5%CO2. Use an inverted microscope to check the detachment of the cells. If necessary, move the cell culture dish gently to detach more cells, and be careful not to shake it.Next, add 10 milliliters of DMEM plus 10%FBS and pipette the cells up and down, gently, five times. After that, look at the cells under a microscope. If more than 80%of the cells are already separated, no further pipetting is needed.If the cells are still in clusters, continue gently pipetting until more than 80%of the cells are no longer in clusters. An optical control of the cells should show many single round cells with smooth membrane edges. Afterwards, proceed with patch-clamp and NLC measurements, as described in the text protocol.HEI-OC1 cells cultured at nonpermissive conditions showed a highly significant decrease in cell viability, and an equally significant increase in cell death in respect to cells cultures at permissive conditions. Since drug effects on cells already dying or with a decreased viability could be different than the effects of the same drug on healthy cells, considerable efforts should be dedicated to discriminate drug effects from the effects of culture conditions in any cytotoxicity study performed on NP-HEI-OC1 cells. Therefore, we recommend using HEI-OC1 cells cultured at permissive conditions for experiments that do not specifically require differentiated cells.The confocal images shown here confirm the expression of the auditory motor protein prestin in HEI-OC1 cells cultured at 33 degrees Celsius and 39 degrees Celsius. Note that prestin immunolocalizes mostly at the cytoplasm of HEI-OC1 cells growing in the permissive conditions, and it is more concentrated at the plasma membrane in the more differentiated cells. Flow cytometry studies showed a clear increase in prestin expression in both conditions, suggesting that translocation was accompanied by synthesis of more prestin molecules.On the other hand, the electrophysiological studies showed a robust NLC in HEI-OC1 cells growing at 33 degrees Celsius, with a peak value that decreased and a voltage at peak capacitance that shifted to the more depolarized values as the cells were moved to the nonpermissive conditions for one and two weeks. Intriguingly, these results suggest that motor function could be compromised if the density of prestin molecules in the plasma membrane is too high. It is important to remember that the protocols described here require the correct use of well-established cell culture techniques.Also, remember to avoid the use of antibiotics. In addition, remember that the phenotype and response of HEI-OC1 cells will strongly depend on the culture parameters.

Research

JoVE Journal

Biology

Labeling Stem Cells with Fluorescent Dyes for non-invasive Detection with Optical Imaging

Optical imaging (OI) is an easy, fast and inexpensive tool for in vivo monitoring of new stem cell based therapies. The technique is based on ex vivo labeling of stem cells with a fluorescent dye, subsequent intravenous injection of the labeled cells and visualization of their accumulation in specific target organs or pathologies. The presented technique demonstrates how we label human mesenchymal stem cells (hMSC) by simple incubation with the lipophilic fluorescent dye DiD (C67H103CIN2O3S) and how we label human embryonic stem cells (hESC) with the FDA approved fluorescent dye Indocyanine Green (ICG). The uptake mechanism is via adherence and diffusion of the lypophilic dye across the phospholipid cell membrane bilayer. The labeling efficiency is usually improved if the cells are incubated with the dye in serum-free media as opposed to incubation in serum-containing media. Furthermore, the addition of the transfection agent Protamine Sulfate significantly improves contrast agent uptake.

This video shows techniques for labeling of human embryonic stem cells and mesenchymal stem cells with fluorescent dyes. This technique can be used for an in vivo tracking of transplanted stem cells with optical imaging and for histopathological correlations with fluorescence microscopy.

Optical imaging (OI) is an easy, fast and inexpensive tool for in vivo monitoring of new stem cell based therapies. The technique is based on ex vivo ...

Mapping the After-effects of Theta Burst Stimulation on the Human Auditory Cortex with Functional Imaging

Auditory cortex pertains to the processing of sound, which is at the basis of speech or music-related processing1. However, despite considerable recent progress, the functional properties and lateralization of the human auditory cortex are far from being fully understood. Transcranial Magnetic Stimulation (TMS) is a non-invasive technique that can transiently or lastingly modulate cortical excitability via the application of localized magnetic field pulses, and represents a unique method of exploring plasticity and connectivity. It has only recently begun to be applied to understand auditory cortical function 2. 
An important issue in using TMS is that the physiological consequences of the stimulation are difficult to establish. Although many TMS studies make the implicit assumption that the area targeted by the coil is the area affected, this need not be the case, particularly for complex cognitive functions which depend on interactions across many brain regions 3. One solution to this problem is to combine TMS with functional Magnetic resonance imaging (fMRI). The idea here is that fMRI will provide an index of changes in brain activity associated with TMS. Thus, fMRI would give an independent means of assessing which areas are affected by TMS and how they are modulated 4. In addition, fMRI allows the assessment of functional connectivity, which represents a measure of the temporal coupling between distant regions. It can thus be useful not only to measure the net activity modulation induced by TMS in given locations, but also the degree to which the network properties are affected by TMS, via any observed changes in functional connectivity.
Different approaches exist to combine TMS and functional imaging according to the temporal order of the methods. Functional MRI can be applied before, during, after, or both before and after TMS. Recently, some studies interleaved TMS and fMRI in order to provide online mapping of the functional changes induced by TMS 5-7. However, this online combination has many technical problems, including the static artifacts resulting from the presence of the TMS coil in the scanner room, or the effects of TMS pulses on the process of MR image formation. But more importantly, the loud acoustic noise induced by TMS (increased compared with standard use because of the resonance of the scanner bore) and the increased TMS coil vibrations (caused by the strong mechanical forces due to the static magnetic field of the MR scanner) constitute a crucial problem when studying auditory processing. 
This is one reason why fMRI was carried out before and after TMS in the present study. Similar approaches have been used to target the motor cortex 8,9, premotor cortex 10, primary somatosensory cortex 11,12 and language-related areas 13, but so far no combined TMS-fMRI study has investigated the auditory cortex. The purpose of this article is to provide details concerning the protocol and considerations necessary to successfully combine these two neuroscientific tools to investigate auditory processing. 
Previously we showed that repetitive TMS (rTMS) at high and low frequencies (resp. 10 Hz and 1 Hz) applied over the auditory cortex modulated response time (RT) in a melody discrimination task 2. We also showed that RT modulation was correlated with functional connectivity in the auditory network assessed using fMRI: the higher the functional connectivity between left and right auditory cortices during task performance, the higher the facilitatory effect (i.e. decreased RT) observed with rTMS. However those findings were mainly correlational, as fMRI was performed before rTMS. Here, fMRI was carried out before and immediately after TMS to provide direct measures of the functional organization of the auditory cortex, and more specifically of the plastic reorganization of the auditory neural network occurring after the neural intervention provided by TMS. 
Combined fMRI and TMS applied over the auditory cortex should enable a better understanding of brain mechanisms of auditory processing, providing physiological information about functional effects of TMS. This knowledge could be useful for many cognitive neuroscience applications, as well as for optimizing therapeutic applications of TMS, particularly in auditory-related disorders.

Auditory processing is the basis of speech and music-related processing. Transcranial Magnetic Stimulation (TMS) has been used successfully to study cognitive, sensory and motor systems but has rarely been applied to audition. Here we investigated TMS combined with functional Magnetic Resonance Imaging to understand the functional organization of auditory cortex.

Auditory cortex pertains to the processing of sound, which is at the basis of speech or music-related processing1. However, despite considerable recent ...

Induction and Analysis of Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is essential for proper morphogenesis during development. Misregulation of this process has been implicated as a key event in fibrosis and the progression of carcinomas to a metastatic state. Understanding the processes that underlie EMT is imperative for the early diagnosis and clinical control of these disease states. Reliable induction of EMT in vitro is a useful tool for drug discovery as well as to identify common gene expression signatures for diagnostic purposes. Here we demonstrate a straightforward method for the induction of EMT in a variety of cell types. Methods for the analysis of cells pre- and post-EMT induction by immunocytochemistry are also included. Additionally, we demonstrate the effectiveness of this method through antibody-based array analysis and migration/invasion assays.

A straightforward method is described for the induction of epithelial to mesenchymal transition (EMT) in a variety of cell types. Methods for the analysis of cells in EMT states by immunocytochemistry are included.

Epithelial  to mesenchymal transition (EMT) is essential for proper morphogenesis during  development. Misregulation of this  process has been implicated ...

Fluorescence Imaging with One-nanometer Accuracy (FIONA)

Fluorescence imaging with one-nanometer accuracy (FIONA) is a simple but useful technique for localizing single fluorophores with nanometer precision in the x-y plane. Here a summary of the FIONA technique is reported and examples of research that have been performed using FIONA are briefly described. First, how to set up the required equipment for FIONA experiments, i.e., a total internal reflection fluorescence microscopy (TIRFM), with details on aligning the optics, is described. Then how to carry out a simple FIONA experiment on localizing immobilized Cy3-DNA single molecules using appropriate protocols, followed by the use of FIONA to measure the 36 nm step size of a single truncated myosin Va motor labeled with a quantum dot, is illustrated. Lastly, recent effort to extend the application of FIONA to thick samples is reported. It is shown that, using a water immersion objective and quantum dots soaked deep in sol-gels and rabbit eye corneas (&#62;200 &#181;m), localization precision of 2-3 nm can be achieved.

Fluorescence Imaging with One-nanometer Accuracy FIONA

Single fluorophores can be localized with nanometer precision using FIONA. Here a summary of the FIONA technique is reported, and how to carry out FIONA experiments is described.

Fluorescence imaging with one-nanometer accuracy (FIONA) is a simple but useful technique for localizing single fluorophores with nanometer precision in ...

Transfecting RAW264.7 Cells with a Luciferase Reporter Gene

Transfection of desired genetic materials into cells is an inevitable procedure in biomedical research studies. While numerous methods have been described, certain types of cells are resistant to many of these methods and yield low transfection efficiency1, potentially hindering research in those cell types. In this protocol, we present an optimized transfection procedure to introduce luciferase reporter genes as a plasmid DNA into the RAW264.7 macrophage cell line. Two different types of transfection reagents (lipid-based and polyamine-based) are described, and important notes are given throughout the protocol to ensure that the RAW264.7 cells are minimally altered by the transfection procedure and any experimental data obtained are the direct results of the experimental treatment. While transfection efficiency may not be higher compared to other transfection methods, the described procedure is robust enough for detecting luciferase signal in RAW264.7 without changing the physiological response of the cells to stimuli.

Transfection into the macrophage cell line, RAW264.7, is difficult due to the cell&#8217;s natural response against foreign materials. We described here a gentle yet robust procedure for transfecting luciferase reporter genes into RAW264.7 cells.

Transfection of desired genetic materials into cells is an inevitable procedure in biomedical research studies. While numerous methods have been ...

Rodent Working Heart Model for the Study of Myocardial Performance and Oxygen Consumption

Isolated working heart models have been used to understand the effects of loading conditions, heart rate and medications on myocardial performance in ways that cannot be accomplished in vivo. For example, inotropic medications commonly also affect preload and afterload, precluding load-independent assessments of their myocardial effects in vivo. Additionally, this model allows for sampling of coronary sinus effluent without contamination from systemic venous return, permitting assessment of myocardial oxygen consumption. Further, the advent of miniaturized pressure-volume catheters has allowed for the precise quantification of markers of both systolic and diastolic performance. We describe a model in which the left ventricle can be studied while performing both volume and pressure work under controlled conditions. 
In this technique, the heart and lungs of a Sprague-Dawley rat (weight 300-500 g) are removed en bloc under general anesthesia. The aorta is dissected free and cannulated for retrograde perfusion with oxygenated Krebs buffer. The pulmonary arteries and veins are ligated and the lungs removed from the preparation. The left atrium is then incised and cannulated using a separate venous cannula, attached to a preload block. Once this is determined to be leak-free, the left heart is loaded and retrograde perfusion stopped, creating the working heart model. The pulmonary artery is incised and cannulated for collection of coronary effluent and determination of myocardial oxygen consumption. A pressure-volume catheter is placed into the left ventricle either retrograde or through apical puncture. If desired, atrial pacing wires can be placed for more precise control of heart rate. This model allows for precise control of preload (using a left atrial pressure block), afterload (using an afterload block), heart rate (using pacing wires) and oxygen tension (using oxygen mixtures within the perfusate).

Isolated working heart models can be used to measure the effect of loading conditions, heart rate, and medications on myocardial performance and oxygen consumption. We describe methods for preparation of a rodent left heart working model that permits study of systolic and diastolic performance and oxygen consumption under various conditions.

Isolated working heart models have been used to understand the effects of loading conditions, heart rate and medications on myocardial performance in ways ...

Nephrotoxin Microinjection in Zebrafish to Model Acute Kidney Injury

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid decline in renal function and development of the clinical syndrome known as acute kidney injury (AKI). Pharmacological agents used to treat medical circumstances ranging from bacterial infection to cancer, when administered individually or in combination with other drugs, can initiate AKI. Zebrafish are a useful animal model to study the chemical effects on renal function in vivo, as they form an embryonic kidney comprised of nephron functional units that are conserved with higher vertebrates, including humans. Further, zebrafish can be utilized to perform genetic and chemical screens, which provide opportunities to elucidate the cellular and molecular facets of AKI and develop therapeutic strategies such as the identification of nephroprotective molecules. Here, we demonstrate how microinjection into the zebrafish embryo can be utilized as a paradigm for nephrotoxin studies.

Renal injuries incurred from nephrotoxins, which include drugs ranging from antibiotics to chemotherapeutics, can result in complex disorders whose pathogenesis remains incompletely understood. This protocol demonstrates how zebrafish can be used for disease modeling of these conditions, which can be applied to the identification of renoprotective measures.

The kidneys are susceptible to harm from exposure to chemicals they filter from the bloodstream. This can lead to organ injury associated with a rapid ...

Methods for the Determination of Rates of Glucose and Fatty Acid Oxidation in the Isolated Working Rat Heart

The mammalian heart is a major consumer of ATP and requires a constant supply of energy substrates for contraction. Not surprisingly, alterations of myocardial metabolism have been linked to the development of contractile dysfunction and heart failure. Therefore, unraveling the link between metabolism and contraction should shed light on some of the mechanisms governing cardiac adaptation or maladaptation in disease states. The isolated working rat heart preparation can be used to follow, simultaneously and in real time, cardiac contractile function and flux of energy providing substrates into oxidative metabolic pathways. The present protocol aims to provide a detailed description of the methods used in the preparation and utilization of buffers for the quantitative measurement of the rates of oxidation for glucose and fatty acids, the main energy providing substrates of the heart. The methods used for sample analysis and data interpretation are also discussed. In brief, the technique is based on the supply of 14C- radiolabeled glucose and a 3H- radiolabeled long-chain fatty acid to an ex vivo beating heart via normothermic crystalloid perfusion. 14CO2 and 3H2O, end byproducts of the enzymatic reactions involved in the utilization of these energy providing substrates, are then quantitatively recovered from the coronary effluent. With knowledge of the specific activity of the radiolabeled substrates used, it is then possible to individually quantitate the flux of glucose and fatty acid in the oxidation pathways. Contractile function of the isolated heart can be determined in parallel with the appropriate recording equipment and directly correlated to metabolic flux values. The technique is extremely useful to study the metabolism/contraction relationship in response to various stress conditions such as alterations in pre and after load and ischemia, a drug or a circulating factor, or following the alteration in the expression of a gene product.

The following protocol describes the preparation and utilization of buffers for the quantitative measurement of rates of glucose and fatty acid oxidation in the isolated working rat heart. The methods used for sample analysis and data interpretation are also discussed.

The mammalian heart is a major consumer of ATP and requires a constant supply of energy substrates for contraction. Not surprisingly, alterations of ...

A Graphical User Interface for Software-assisted Tracking of Protein Concentration in Dynamic Cellular Protrusions

Filopodia are dynamic, finger-like cellular protrusions associated with migration and cell-cell communication. In order to better understand the complex signaling mechanisms underlying filopodial initiation, elongation and subsequent stabilization or retraction, it is crucial to determine the spatio-temporal protein activity in these dynamic structures. To analyze protein function in filopodia, we recently developed a semi-automated tracking algorithm that adapts to filopodial shape-changes, thus allowing parallel analysis of protrusion dynamics and relative protein concentration along the whole filopodial length. Here, we present a detailed step-by-step protocol for optimized cell handling, image acquisition and software analysis. We further provide instructions for the use of optional features during image analysis and data representation, as well as troubleshooting guidelines for all critical steps along the way. Finally, we also include a comparison of the described image analysis software with other programs available for filopodia quantification. Together, the presented protocol provides a framework for accurate analysis of protein dynamics in filopodial protrusions using image analysis software.

We present a software solution for semi-automated tracking of relative protein concentration along the length of dynamic cellular protrusions.

Filopodia are dynamic, finger-like cellular protrusions associated with migration and cell-cell communication. In order to better understand the complex ...

In Situ Monitoring of Transiently Formed Molecular Chaperone Assemblies in Bacteria, Yeast, and Human Cells

J-domain proteins (JDPs) form the largest and the most diverse co-chaperone family in eukaryotic cells. Recent findings show that specific members of the JDP family could form transient heterocomplexes in eukaryotes to fine-tune substrate selection for the 70 kDa heat shock protein (Hsp70) chaperone-based protein disaggregases. The JDP complexes target acute/chronic stress induced aggregated proteins and presumably help assemble the disaggregases by recruiting multiple Hsp70s to the surface of protein aggregates. The extent of the protein quality control (PQC) network formed by these physically interacting JDPs remains largely uncharacterized in vivo. Here, we describe a microscopy-based in situ protein interaction assay named the proximity ligation assay (PLA), which is able to robustly capture&#160;these transiently formed chaperone complexes in distinct cellular compartments of eukaryotic cells. Our work expands the employment of PLA from human cells to yeast (Saccharomyces cerevisiae) and bacteria (Escherichia coli), thus rendering an important tool to monitor the dynamics of transiently formed protein assemblies in both prokaryotic and eukaryotic cells.

Cognate J-domain proteins cooperate with the Hsp70 chaperone to assist in a myriad of biological processes ranging from protein folding to degradation. Here, we describe an in situ proximity ligation assay, which allows the monitoring of these transiently formed chaperone machineries in bacterial, yeast and human cells.

J-domain proteins (JDPs) form the largest and the most diverse co-chaperone family in eukaryotic cells. Recent findings show that specific members of the ...