Name: high-resolution respirometry to measure mitochondrial function of intact beta cells in the presence of natural compounds
Uploaded: 2018-01-23T15:00:00
Description: Watch this Scientific Journal Video about High-resolution Respirometry to Measure Mitochondrial Function of Intact Beta Cells in the Presence of Natural Compounds at JoVE.com

The authors would like to thank members of the Tessem and Hancock labs for assistant and scientific discussion. The authors thank Andrew Neilson, PhD (Virginia Tech) for providing the cocoa derived epicatechin monomer fraction. This study was supported by a grant from the Diabetes Action Research and Education Foundation to JST.

1. Cell Culture
<ol>
	<li>Culture INS-1 derived 832/13 beta cells in RPMI 1640 supplemented with 10% fetal bovine serum (FBS), 1% penicillin-streptomycin, 10 mM HEPES, 2 mM Glutamine, 1 mM Sodium Pyruvate, and 0.05 mM 2-mercaptoethanol9,10,11,12,13.</li>
	<li>Remove 832/13 cells from a T75 flask using 2 mL of 0.25% trypsin, incubating at 37 &#176;C for 10 mi...

<ol>
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C., Bonner-Weir, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Five+stages+of+evolving+beta-cell+dysfunction+during+progression+to+diabetes.">Five stages of evolving beta-cell dysfunction during progression to diabetes.</a> Diabetes. 53 Suppl 3, S16-S21 (2004).</li><li>Strat, K. 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=Mechanisms+by+which+cocoa+flavanols+improve+metabolic+syndrome+and+related+disorders.">Mechanisms by which cocoa flavanols improve metabolic syndrome and related disorders.</a> J Nutr Biochem. 35, 1-21 (2016).</li><li>Rowley, T. J. 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=Monomeric+cocoa+catechins+enhance+&#946;-cell+function+by+increasing+mitochondrial+respiration.">Monomeric cocoa catechins enhance &#946;-cell function by increasing mitochondrial respiration.</a> J Nutr Biochem. 49, 30-41 (2017).</li><li>Djafarzadeh, S., Jakob, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-resolution+Respirometry+to+Assess+Mitochondrial+Function+in+Permeabilized+and+Intact+Cells.">High-resolution Respirometry to Assess Mitochondrial Function in Permeabilized and Intact Cells.</a> J Vis Exp. (120), (2017).</li><li>Reynolds, M. 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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=Nkx6.1-mediated+insulin+secretion+and+beta-cell+proliferation+is+dependent+on+upregulation+of+c-Fos.">Nkx6.1-mediated insulin secretion and beta-cell proliferation is dependent on upregulation of c-Fos.</a> FEBS Lett. 590 (12), 1791-1803 (2016).</li><li>Schisler, J. 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=Stimulation+of+human+and+rat+islet+beta-cell+proliferation+with+retention+of+function+by+the+homeodomain+transcription+factor+Nkx6.1.">Stimulation of human and rat islet beta-cell proliferation with retention of function by the homeodomain transcription factor Nkx6.1.</a> Mol Cell Biol. 28 (10), 3465-3476 (2008).</li><li>Tessem, J. 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=Nkx6.1+regulates+islet+beta-cell+proliferation+via+Nr4a1+and+Nr4a3+nuclear+receptors.">Nkx6.1 regulates islet beta-cell proliferation via Nr4a1 and Nr4a3 nuclear receptors.</a> Proc Natl Acad Sci U S A. 111 (14), 5242-5247 (2014).</li><li>Hobson, 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=Aurora+Kinase+A+is+critical+for+the+Nkx6.1+mediated+beta-cell+proliferation+pathway.">Aurora Kinase A is critical for the Nkx6.1 mediated beta-cell proliferation pathway.</a> Islets. 7 (1), e1027854 (2015).</li><li>Draney, C., Hobson, A. E., Grover, S. G., Jack, B. O., Tessem, 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=Cdk5r1+Overexpression+Induces+Primary+beta-Cell+Proliferation.">Cdk5r1 Overexpression Induces Primary beta-Cell Proliferation.</a> J Diabetes Res. 2016, 6375804 (2016).</li><li>Rouse, M., Younes, A., Egan, 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=Resveratrol+and+curcumin+enhance+pancreatic+beta-cell+function+by+inhibiting+phosphodiesterase+activity.">Resveratrol and curcumin enhance pancreatic beta-cell function by inhibiting phosphodiesterase activity.</a> J Endocrinol. 223 (2), 107-117 (2014).</li><li>Ma, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diabetes+reduces+beta-cell+mitochondria+and+induces+distinct+morphological+abnormalities,+which+are+reproducible+by+high+glucose+in+vitro+with+attendant+dysfunction.">Diabetes reduces beta-cell mitochondria and induces distinct morphological abnormalities, which are reproducible by high glucose in vitro with attendant dysfunction.</a> Islets. 4 (3), 233-242 (2012).</li><li>Chavanelle, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+high-intensity+interval+training+and+moderate-intensity+continuous+training+on+glycaemic+control+and+skeletal+muscle+mitochondrial+function+in+db/db+mice.">Effects of high-intensity interval training and moderate-intensity continuous training on glycaemic control and skeletal muscle mitochondrial function in db/db mice.</a> Sci Rep. 7 (1), 204 (2017).</li><li>Jelenik, 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=Mechanisms+of+Insulin+Resistance+in+Primary+and+Secondary+Nonalcoholic+Fatty+Liver.">Mechanisms of Insulin Resistance in Primary and Secondary Nonalcoholic Fatty Liver.</a> Diabetes. 66 (8), 2241-2253 (2017).</li><li>Spacek, 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=Glucose-stimulated+insulin+secretion+of+insulinoma+INS-1E+cells+is+associated+with+elevation+of+both+respiration+and+mitochondrial+membrane+potential.">Glucose-stimulated insulin secretion of insulinoma INS-1E cells is associated with elevation of both respiration and mitochondrial membrane potential.</a> Int J Biochem Cell Biol. 40 (8), 1522-1535 (2008).</li><li>Jezek, J., Dlaskova, A., Zelenka, J., Jaburek, M., Jezek, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=H2O2-Activated+Mitochondrial+Phospholipase+iPLAgamma+Prevents+Lipotoxic+Oxidative+Stress+in+Synergy+with+UCP2,+Amplifies+Signaling+via+G-Protein-Coupled+Receptor+GPR40,+and+Regulates+Insulin+Secretion+in+Pancreatic+beta-Cells.">H2O2-Activated Mitochondrial Phospholipase iPLAgamma Prevents Lipotoxic Oxidative Stress in Synergy with UCP2, Amplifies Signaling via G-Protein-Coupled Receptor GPR40, and Regulates Insulin Secretion in Pancreatic beta-Cells.</a> Antioxid Redox Signal. 23 (12), 958-972 (2015).</li><li>Johnson, J. 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=Suppressed+insulin+signaling+and+increased+apoptosis+in+CD38-null+islets.">Suppressed insulin signaling and increased apoptosis in CD38-null islets.</a> Diabetes. 55 (10), 2737-2746 (2006).</li></ol>

The objective of this protocol is to use high-resolution respirometry to measure respiratory rates in intact pancreatic beta cells. This method allows the measurement of the beta cell response to increased glucose levels. The protocol also allows for the pretreatment with various compounds, as demonstrated in this protocol with the naturally occurring monomeric epicatechin or curcumin4,5. Treatment with various other compounds cou...

The primary purpose of the pancreatic beta cell is to maintain system normoglycemia through glucose-stimulated insulin secretion. The beta cells sense physiological changes in circulating glucose largely due to the low affinity, high capacity glucose transporter GLUT2 (Glucose Transporter 2, Km 16.7 mM)1. As circulatory glucose levels rise, this high-capacity low-affinity transporter facilitates a proportional increase in intracellular glucose within the beta cell. Glucose is metabolized through glycolysis, the TCA cycle (tricarboxylic acid cycle) and mitochondrial respiration resulting in elevated cellular ATP (adenosine triphosphate) levels. The elevated ATP concentration blocks the ATP sensitive K+ channels, resulting in membrane depolarization. Membrane depolarization causes the opening of voltage gated Ca2+ channels and subsequent release of vesicle bound insulin granules2. Beta cell dysfunction is a hallmark of Type 2 Diabetes (T2D), and results in decreased and poorly controlled insulin secretion and ultimately beta cell death3. Mechanisms that maintain or improve beta cell function could be used as a treatment for T2D.
Studies have demonstrated the beneficial effects of naturally occurring plant-based compounds on the pancreatic beta cell4. These compounds may have their effect through increasing beta cell proliferation, survival, or glucose-stimulated insulin secretion. As an example, recent studies have demonstrated that monomeric epicatechin enhances glucose-stimulated insulin secretion through increasing mitochondrial respiration and increasing cellular ATP levels5. Therefore, understanding how these compounds can increase functional beta cell mass is important to leverage these compounds as potential therapeutics.
Cellular respiration can be measured through a number of tools. Use of a high-resolution respirometer allows for titration of chemical modulators to a permeabilized or intact cell population6. This tool permits the addition of various compounds, at different concentrations, thus giving a wide array of information.
Given the intimate connection between glucose metabolism and beta cell function, measurements of cellular respiration are critical. Measurements of cellular respiration can be done using either permeabilized or intact beta cells, with each having its own set of benefits and drawbacks7,8. While permeabilization of beta cells allows one to measure different aspects of the electron transport chain, it does so without regards to the mechanism for inducing respiration in the beta cell, glucose uptake and metabolism. Therefore, use of unpermeabilized beta cell respiration is a very useful technique to determine the beta cells response to various glucose levels, using oxygen consumption as the readout.
The purpose of this technique is to measure oxygen consumption in intact INS-1 derived 832/13 beta cells. This technique allows us to determine the response of the beta cells to unstimulatory glucose conditions (2.5 mM glucose) as well as stimulatory glucose conditions (16.7 mM glucose). While the unpermeabilized cells do not allow us to individually test complex I, II or III of the electron transport chain, the technique does permit measurements dealing with complex IV inhibition (Oligomycin A), uncoupled respiration (FCCP-Carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone), and completely inhibited respiration (Antimycin A). This study demonstrates the efficacy of measuring respiration in intact unpermeabilized pancreatic beta cells, as well as the effect of two naturally occurring compounds, monomeric epicatechin and curcumin, on beta cell respiration.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>O2k Core: Oxygraph-2k</td>
			<td>Oroboros Instruments</td>
			<td>10000-02</td>
			<td>Instrument for high-resolution respirometry</td>
		</tr>
		<tr>
			<td>DatLab 6 Program</td>
			<td>Oroboros Instruments</td>
			<td>27141-01</td>
			<td>Computer program for analysing high-reolution respirometry</td>
		</tr>
		<tr>
			<td>INS-1 832/13 cell line</td>
			<td>Duke University Medical Center</td>
			<td>NONE</td>
			<td>Beta cell line, gift from Dr. Christopher Newgard</td>
		</tr>
		<tr>
			<td>Curcumin</td>
			<td>Sigma</td>
			<td>C7727</td>
			<td>Pre-treatment of beta cells</td>
		</tr>
		<tr>
			<td>Cocoa epicatechin monomer</td>
			<td>Virginia Polytechnic Institute and State University</td>
			<td>NONE</td>
			<td>Pre-treatment of beta cells, gift from Dr. Andrew Neilson</td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Sigma</td>
			<td>T4049</td>
			<td>For cell culture</td>
		</tr>
		<tr>
			<td>RPMI-1640</td>
			<td>Sigma</td>
			<td>R8758</td>
			<td>832/13 beta cell media</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum</td>
			<td>Hyclone</td>
			<td>SH30071.03</td>
			<td>832/13 beta cell media component</td>
		</tr>
		<tr>
			<td>Penicillin-streptomycin</td>
			<td>Sigma</td>
			<td>P4458</td>
			<td>832/13 beta cell media component</td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma</td>
			<td>H3662</td>
			<td>832/13 beta cell media component/ 1x SAB Buffer</td>
		</tr>
		<tr>
			<td>Glutamine</td>
			<td>Caisson</td>
			<td>GLL01</td>
			<td>832/13 beta cell media component</td>
		</tr>
		<tr>
			<td>Sodium Pyruvate</td>
			<td>Sigma</td>
			<td>S8636</td>
			<td>832/13 beta cell media component</td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Sigma</td>
			<td>M3148</td>
			<td>832/13 beta cell media component</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Fisher</td>
			<td>S271</td>
			<td>Component of 10x SAB buffer</td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma</td>
			<td>P9541</td>
			<td>Component of 10x SAB buffer</td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma</td>
			<td>P5655</td>
			<td>Component of 10x SAB buffer</td>
		</tr>
		<tr>
			<td>MgSO4</td>
			<td>Sigma</td>
			<td>M2643</td>
			<td>Component of 10x SAB buffer</td>
		</tr>
		<tr>
			<td>D-(+)-Glucose Solution</td>
			<td>Sigma</td>
			<td>G8769</td>
			<td>Component of 1x SAB buffer, chemical for respiration assay</td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>Sigma</td>
			<td>C5670</td>
			<td>Component of 1x SAB buffer</td>
		</tr>
		<tr>
			<td>35% BSA Solution</td>
			<td>Sigma</td>
			<td>A7979</td>
			<td>Component of 1x SAB buffer</td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Sigma</td>
			<td>S5761</td>
			<td>Component of 1x SAB buffer</td>
		</tr>
		<tr>
			<td>200 proof ethanol</td>
			<td>Sigma</td>
			<td>459844</td>
			<td>Washing Oxygraph O2k Chambers</td>
		</tr>
		<tr>
			<td>Oligomycin A</td>
			<td>Sigma</td>
			<td>O4876</td>
			<td>Chemicals for respiration assay</td>
		</tr>
		<tr>
			<td>FCCP</td>
			<td>Sigma</td>
			<td>C2920</td>
			<td>Chemicals for respiration assay</td>
		</tr>
		<tr>
			<td>Anitmycin A</td>
			<td>Sigma</td>
			<td>A8674</td>
			<td>Chemicals for respiration assay</td>
		</tr>
		<tr>
			<td>BCA Protein Kit</td>
			<td>Thermo Fisher</td>
			<td>23225</td>
			<td>For determining protein concentration</td>
		</tr>
	</tbody>
</table>

high-resolution respirometry to measure mitochondrial function of intact beta cells in the presence of natural compounds

High-resolution respirometry allows for the measurement of oxygen consumption of isolated mitochondria, cells and tissues. Beta cells play a critical role in the body by controlling blood glucose levels through insulin secretion in response to elevated glucose concentrations. Insulin secretion is controlled by glucose metabolism and mitochondrial respiration. Therefore, measuring intact beta cell respiration is essential to be able to improve beta cell function as a treatment for diabetes. Using intact 832/13 INS-1 derived beta cells we can measure the effect of increasing glucose concentration on cellular respiration. This protocol allows us to measure beta cell respiration in the presence or absence of various compounds, allowing one to determine the effect of given compounds on intact cell respiration. Here we demonstrate the effect of two naturally occurring compounds, monomeric epicatechin and curcumin, on beta cell respiration under the presence of low (2.5 mM) or high glucose (16.7 mM) conditions. This technique can be used to determine the effect of various compounds on intact beta cell respiration in the presence of differing glucose concentrations.

INS-1 832/13 beta cells that are prepared and harvested as described in the protocol will demonstrate modulation in oxygen consumption based on the various chemical interventions (Figure 1A). An increase in respiration will be observed when the glucose concentration is increased to 16.7 mM Glucose (Figure 1B). Respiration will decrease when the intact cells are treated with Oligomycin A. This respiration is known as LEAK, which is defined as the basal, nonphosph...

Watch this Scientific Journal Video about High-resolution Respirometry to Measure Mitochondrial Function of Intact Beta Cells in the Presence of Natural Compounds at JoVE.com

High-resolution Respirometry to Measure Mitochondrial Function of Intact Beta Cells in the Presence of Natural Compounds

The goal of this protocol is to measure the effect of glucose-mediated changes to mitochondrial respiration in the presence of natural compounds on intact 832/13 beta cells using high-resolution respirometry.

High-resolution respirometry allows for the measurement of oxygen consumption of isolated mitochondria, cells and tissues. Beta cells play a critical role ...

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