We thank Jianhua Ling, Raymond MacDonald, Galvin Swift, Michelle Griffin, Paul Grippo and Satyanarayana Rachagani for their helpful comments, suggestions and sharing of their protocols. This work was supported by grant U01CA111294 and an Idea Development Award from the Ohio State University Intramural Research Program.

1. Preparation
The following practices adhere to the policies set by the Institution&#8217;s Animal Care and Use Committee (IACUC).
<ol>
	<li>It is recommended to isolate no more than 6 mouse pancreases in any given day. Have all surgical instruments clean and autoclaved, one set per animal.</li>
	<li>Label all microcentrifuge tubes. Four 2 ml tubes per animal.</li>
	<li>Place 8 ml of lysis reagent in 50 ml centrifuge tubes on ice. Note: While the purification kit comes with a guanidine thiocyanate phenol reagent that is suitable for pancreas isolation, lysis reagent is used because of the large volumes that are necessary per isolation.</li>
	<li>Dispense about 10 ml of the following solutions into 15 ml centrifuge tubes for cleaning the homogenizer&#8217;s blades. Ethanol, 70% (2 tubes), HPLC grade water (1 tube) and HPLC grade water containing approximately 200 &#181;l of RNase Away or equivalent ribonuclease inactivator.</li>
</ol>
2. Surgery, Pancreas Dissection and Homogenization
<ol>
	<li>Place 1-2 ml of isoflurane into a jar containing cotton gauze or paper towels. Mice are placed on a platform that prevents them from reaching the source of the isoflurane. Add fresh isoflurane to the jar prior to anesthetizing each mouse.</li>
	<li>Gently place the mouse into the jar containing the isoflurane. Cap the jar and monitor the effects of the anesthesia by gently rotating the jar back and forth. The animal is anesthetized once it is in unable to stand in its&#8217; own.</li>
	<li>For confirmation of anesthesia, remove the animal from the jar and apply a firm toe pinch. If the mouse does not react to the toe pinch, proceed to step 2.5.</li>
	<li>If the mouse reacts to the toe pinch, then repeat steps 2.2 to 2.3.</li>
	<li>Place the anesthetized animal on the bench top in the prone position. Dislocate the mouse&#8217;s cervix by tightly placing the left hand on the mouse&#8217;s cervix. Using the right hand grasp the mouse&#8217;s tail and quickly pull upwards at approximately a 45&#176; angle to dislocate the cervix.</li>
	<li>Secure the carcass to a surface (a level piece of styrofoam covered with paper towels) by piercing each of the animal&#8217;s four paws into the flat surface using 25 gauge hypodermic needles.</li>
	<li>Using sterile surgical instruments, cut the midsection of the mouse open and quickly remove the pancreas from the mouse. Use the forceps to hold the pancreas and cut it from the spleen and small intestine using spring scissors. Be careful not to stretch the pancreas during the removal from the mouse. Disruption of the tissue could release ribonuclease. Note: The time it takes to remove the pancreas from the mouse is critical. A skilled person should be able to dissect the pancreas in about 1 min or less.</li>
	<li>Place the entire pancreas into a 50 ml tube containing 8 ml of ice cold lysis reagent. Cap the tube and briefly shake to immerse the tissue into the reagent and proceed to the next step without delay. The ratio of lysis reagent to tissue is critical. See Results section for a comparison of the RNA integrity isolated using different volumes of lysis reagent.</li>
	<li>Homogenize for 5 sec. It is important to press the homogenizer blades to the bottom of the centrifuge tube to allow the tissue to be pulled into the blades for efficient homogenization.</li>
</ol>
3. Removal of Undigested Tissue
Note: Following homogenization, small bits of tissue will remain in the lysis reagent. It is more important to quickly lyse the tissue leaving some tissue undigested rather than over homogenizing and risk degradation of RNA.
<ol>
	<li>Transfer 2 ml of lysis reagent containing the lysed pancreas to a 2 ml microcentrifuge tube. Collect two microcentrifuge tubes of homogenate per isolation. Discard the remaining homogenate or store at -80 &#176;C for future studies.</li>
	<li>Centrifuge at 4 &#176;C, 12,000 &#215; g for 5 min to pellet the undigested tissue. This is a critical step as carryover of undigested tissue into subsequent solutions of RNA will likely contaminate the sample with ribonuclease (step 5.13).</li>
	<li>Transfer 1 ml of the supernatant into a 2 ml microcentrifuge tube. Proceed with the isolation immediately and store the replicate tube at -80 &#176;C for future use. Place all tubes containing homogenate on wet ice while proceeding to the next step.</li>
	<li>Dispose of the remaining lysis reagent into an appropriate chemical waste receptacle.</li>
</ol>
4. Cleaning of the Homogenizer Blades
<ol>
	<li>Before proceeding to the next isolation, clean the homogenizer blades by placing them in 10 ml of 70% ethanol. Activate the homogenizer for about for 20 sec to remove any chunks of tissue that may be caught in the blades.</li>
	<li>Use a 200 &#181;l pipet tip to remove any pieces that remain in the homogenizer blades.</li>
	<li>Repeat step 4.1 in water, general Rnase inactivator and 70% ethanol. Dry the homogenizer shaft with a clean Kim wipe.</li>
	<li>Repeat step 2.1 for the pancreas isolation of the remaining animals, keeping RNA isolated from each animal separate rather than pooling the RNA.</li>
</ol>
5. RNA Isolation
The following section is identical to the purification kit protocol. The advantage of the purification kit is that it will isolate total RNA including small RNAs.
<ol>
	<li>If using frozen homogenate solution, thaw on wet ice and let stand at RT for 5 min.</li>
	<li>Add 200 &#181;l of chloroform, cap the tube and shake vigorously by hand for 15 sec. Let the tube stand at RT for 2-3 min.</li>
	<li>Centrifuge for 15 min at 12,000 x g, 4 &#176;C.</li>
	<li>Transfer the upper aqueous layer into a microcentrifuge tube. Add 1.5 volumes of isopropanol and mix thoroughly by pipetting up and down several times.</li>
	<li>Transfer up to 700 &#956;l of the sample into a spin column that is placed in a 2 ml collection tube. Close the lid and centrifuge at 8,000 x g for 15 sec at RT.</li>
	<li>Discard the flow-through.</li>
	<li>Repeat steps 5.5-5.6, using the remainder of the sample.</li>
	<li>Add 700 &#956;l Buffer RWT to the spin column. Centrifuge for 15 sec at 8,000 x g. Discard the flow-through.</li>
	<li>Pipet 500 &#956;l Buffer RPE into the spin column. Centrifuge for 15 sec at 8,000 x g to wash the column. Discard the flow-through.</li>
	<li>Add 500 &#956;l Buffer RPE to the spin column. Centrifuge for 2 min at 8,000 x g to dry the column.</li>
	<li>Transfer the spin column to a 1.5 ml microcentrifuge tube. Pipet 80 &#956;l ribonuclease-free water directly onto the spin column membrane. Centrifuge for 1 min at 8,000 x g to elute the RNA.</li>
	<li>Add 1 &#181;l Rnase inhibitor to the RNA solution. Store at -80 &#176;C or proceed to 5.13.</li>
	<li>To validate the integrity of the RNA, first calculate the RNA concentration and 260/280 ratio using a spectrophotometer.</li>
	<li>Dilute a portion of the RNA solution to approximately 500 ng/&#181;l with molecular biology grade water.</li>
	<li>Determine the RNA Integrity (i.e., RIN) using capillary electrophoresis analysis. Approximately 5 &#181;l of RNA solution is sufficient for the analysis.</li>
	<li>Aliquot the RNA solution (see Figure 2) and store at -80 &#176;C. &#8195;</li>
</ol>

<ol>
	<li>Chen, C., Ridzon, D. A., Broomer, A. J., Zhou, Z., Lee, D. H., Nguyen, J. T., Barbisin, M., Xu, N. L., Mahuvakar, V. R., Andersen, M. R., 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=Real-time+quantification+of+microRNAs+by+stem-loop+RT-PCR.">Real-time quantification of microRNAs by stem-loop RT-PCR.</a> Nucleic Acids Res. 33, e179 (2005).</li><li>Chirgwin, J. M., Przybyla, A. E., MacDonald, R. J., Rutter, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+of+biologically+active+ribonucleic+acid+from+sources+enriched+in+ribonuclease.">Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease.</a> Biochemistry. 18, 5294-5299 (1979).</li><li>Chomczynski, P., Sacchi, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-step+method+of+RNA+isolation+by+acid+guanidinium+thiocyanate-phenol-chloroform+extraction.">Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction.</a> Anal Biochem. 162, 156-159 (1987).</li><li>Griffin, M., Abu-El-Haija, M., Abu-El-Haija, M., Rokhlina, T., Uc, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simplified+and+versatile+method+for+isolation+of+high-quality+RNA+from+pancreas.">Simplified and versatile method for isolation of high-quality RNA from pancreas.</a> Biotechniques. 52, 332-334 (2012).</li><li>Iyer, V. R., Eisen, M. B., Ross, D. T., Schuler, G., Moore, T., Lee, J. C., Trent, J. M., Staudt, L. M., Hudson Jr, J., Boguski, M. 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=The+transcriptional+program+in+the+response+of+human+fibroblasts+to+serum.">The transcriptional program in the response of human fibroblasts to serum.</a> Science. 283, 83-87 (1999).</li><li>Lenstra, J. A., Beintema, J. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+amino+acid+sequence+of+mouse+pancreatic+ribonuclease.+Extremely+rapid+evolutionary+rates+of+the+myomorph+rodent+ribonucleases.">The amino acid sequence of mouse pancreatic ribonuclease. Extremely rapid evolutionary rates of the myomorph rodent ribonucleases.</a> European journal of biochemistry FEBS. 98, 399-408 (1979).</li><li>Mullin, A. E., Soukatcheva, G., Verchere, C. B., Chantler, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+in+situ+ductal+perfusion+to+facilitate+isolation+of+high-quality+RNA+from+mouse+pancreas.">Application of in situ ductal perfusion to facilitate isolation of high-quality RNA from mouse pancreas.</a> Biotechniques. 40, 617-621 (2006).</li><li>Rio, D. C., Ares, M., Hannon, G. J., Nilsen, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> RNA A Laboratory Manual. , (2011).</li><li>Streit, S., Michalski, C. W., Erkan, M., Kleeff, J., Friess, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Northern+blot+analysis+for+detection+and+quantification+of+RNA+in+pancreatic+cancer+cells+and+tissues.">Northern blot analysis for detection and quantification of RNA in pancreatic cancer cells and tissues.</a> Nat Protoc. 4, 37-43 (2009).</li><li>Zmuda, E. J., Powell, C. A., Hai, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+murine+islet+isolation+and+subcapsular+kidney+transplantation.">A method for murine islet isolation and subcapsular kidney transplantation.</a> Journal of Visualized Experiments JoVE. , (2011).</li></ol>

The authors have nothing to disclose.

Isolating RNA from tissues that are ribonuclease rich represents a great challenge for molecular biology experiments. Various reagents and kits are commercially available that are primarily based upon the phenol guanidine thiocyanate method of RNA extraction. Guanidine thiocyanate denatures protein and thus reduces the activity of ribonuclease. However, the sheer magnitude of ribonuclease in pancreas requires additional modifications to standard protocols of RNA isolation. A protocol is reported here that is based on the...

Isolation of RNA with high integrity is required for routine molecular biology experiments such as northern blotting 9, qRT-PCR 1 or gene expression profiling 5. Most contemporary methods of RNA isolation are based upon modifications of the guanidine thiocyanate protocols 2, 3. Guanidine thiocyanate is a strong protein denaturant and will effectively disrupt the activity of ribonuclease under most conditions. The popular method of Chomczynski and Sacchi 3 combined phenol to the guanidine thiocyanate lysis solution, reducing the isolation time to about 4 hr. Many commercially-available RNA extraction reagents are based upon the Chomczynski and Sacchi method 3.
Ribonuclease rich tissues such as human or mouse pancreas presents an additional challenge for isolating RNA. Mouse pancreas may contain up to 75 mg of ribonuclease 6 some of which will be released during disruption of the pancreatic tissue resulting in tissue autolysis. Modifications of the guanidine thiocyanate protocols have been successfully used to isolate RNA from pancreas with high integrity 2, 4, 7, 10. Infusion of RNA stabilization reagent into mouse pancreas facilitated isolation of RNA with high integrity 4, 7, 10, however infusion of solutions into the pancreas requires great skill, may require specialized instruments such as a dissecting microscope and disrupting tissue architecture during the procedure may result in cell lysis. Perfusing tissue with RNA stabilization reagent might interfere with other applications including protein isolation and histological staining. Furthermore, this technique is not suitable for isolating RNA from human pancreas. Other protocols require the preparation of specific solutions by the investigator 2.
We report a protocol to isolate RNA with high integrity from mouse pancreas. The protocol uses elements of previously published methods and is largely based upon the standard phenol/guanidine thiocyanate-based lysis reagent protocols. It does not require the preparation of specialized solutions nor does it require infusion of reagents into the pancreas. Critical steps for successful RNA isolation include a high phenol/guanidine-based lysis reagent to tissue ratio, removal of undigested tissue prior to phase separation and inclusion of a ribonuclease inhibitor to the resulting RNA solution. Using these and other modifications, we typically isolate RNA with RIN greater than 7 to be used for routine gene expression analysis.

<table border="0" cellpadding="0" cellspacing="0" width="788">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Name of Reagent/ Equipment</td>
			<td style="width:93px;">Company</td>
			<td style="width:119px;">Catalog Number</td>
			<td style="width:360px;">Comments/Description</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Power Gen 500&#160;</td>
			<td style="width:93px;">Fisher Scientific</td>
			<td style="width:119px;">14-261-03&#160;</td>
			<td>Homogenizer</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">5424R</td>
			<td style="width:93px;">Eppendorf</td>
			<td style="width:119px;"></td>
			<td>Refrigerated microcentifuge</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Trizol reagent</td>
			<td style="width:93px;">Invitrogen</td>
			<td style="width:119px;">15596018</td>
			<td>Lysis reagent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Student Vannas spring scissors</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">91500-09&#160;</td>
			<td>use to cut pancreas from attached tissues</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Surgical scissors, 6 inch</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">08-951-20</td>
			<td>use to cut scin of mouse</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Blunt end forceps</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">1381239</td>
			<td>use to hold pancreas while dissecting</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Isoflurane USP</td>
			<td style="width:93px;">Abbott Labs</td>
			<td style="width:119px;">4/8/5210</td>
			<td>Anesthetic</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Rnase out (40 U/&#181;l)</td>
			<td style="width:93px;">Invitrogen</td>
			<td style="width:119px;">10777-019</td>
			<td>Rnase inhbitor</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:216px;">Rnase Away</td>
			<td style="width:93px;">Ambion</td>
			<td style="width:119px;">10328-011</td>
			<td>General Rnase inactivator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">HPLC grade water</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">W5-4</td>
			<td>For washing homogenizer blades</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Molecular Biology grade water</td>
			<td style="width:93px;">Hyclone</td>
			<td style="width:119px;">SH30538.03</td>
			<td>Elution of RNA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">miRNeasy Mini kit</td>
			<td style="width:93px;">Qiagen</td>
			<td style="width:119px;">217004</td>
			<td>Purification Kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">2 ml microcentrifuge tubes, certified Rnase Dnase free</td>
			<td style="width:93px;">USA Scientific Plastics</td>
			<td style="width:119px;">1620-2700</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">15 ml centrifuge tubes</td>
			<td style="width:93px;">Falcon</td>
			<td style="width:119px;">352099</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">70% ethanol</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">100% ethanol</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">200 ul pipet tips</td>
			<td style="width:93px;">Rainin</td>
			<td style="width:119px;">GPL200F</td>
			<td>For cleaning homogenizer blades</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Chloroform</td>
			<td style="width:93px;">Fisher</td>
			<td style="width:119px;">BP1145-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Nanodrop</td>
			<td style="width:93px;">Thermo</td>
			<td style="width:119px;">ND-1000</td>
			<td>Spectrophotometer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Bioanalyzer</td>
			<td style="width:93px;">Agilent</td>
			<td style="width:119px;"></td>
			<td>Capillary electrophoresis analyzer to measue RNA integrity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">RNAlater</td>
			<td style="width:93px;">Ambion</td>
			<td style="width:119px;"></td>
			<td>RNA Stabilization Reagent&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">RNeasy&#160;spin columns&#160;</td>
			<td style="width:93px;">Qiagen</td>
			<td style="width:119px;"></td>
			<td>&#160;spin columns&#160;as a part of the miRNeasy Mini kit</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mice</td>
			<td style="width:93px;">Chales River</td>
			<td style="width:119px;">strain C57BL/6</td>
			<td style="width:360px;">Their age ranged from 4 to 12 months.&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;"></td>
			<td style="width:93px;"></td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mice&#160;</td>
			<td style="width:93px;">Jackson Lab</td>
			<td style="width:119px;">strain 129</td>
			<td style="width:360px;">Their age ranged from 4 to 12 months.&#160;&#160;</td>
		</tr>
	</tbody>
</table>

rna isolation from mouse pancreas: a ribonuclease-rich tissue

Isolation of high-quality RNA from ribonuclease-rich tissue such as mouse pancreas presents a challenge. As a primary function of the pancreas is to aid in digestion, mouse pancreas may contain as much a 75 mg of ribonuclease. We report modifications of standard phenol/guanidine thiocyanate lysis reagent protocols to isolate RNA from mouse pancreas. Guanidine thiocyanate is a strong protein denaturant and will effectively disrupt the activity of ribonuclease under most conditions. However, critical modifications to standard protocols are necessary to successfully isolate RNA from ribonuclease-rich tissues. Key steps include a high lysis reagent to tissue ratio, removal of undigested tissue prior to phase separation and inclusion of a ribonuclease inhibitor to the RNA solution. Using these and other modifications, we routinely isolate RNA with RNA Integrity Number (RIN) greater than 7. The isolated RNA is of suitable quality for routine gene expression analysis. Adaptation of this protocol to isolate RNA from ribonuclease rich tissues besides the pancreas should be readily achievable.

The total RNA yield from 1 ml of lysis homogenate is 20-40 &#181;g. OD 260/280 ratios are typically around 2.0 and the RIN are consistently greater than 7.0. If the RIN is &#8804;6, the isolation will need to be repeated. Occasionally, a RIN that is higher than 8.0 is achieved.
The two most commonly used methods of euthanizing mice prior to removal of the pancreas are CO2 asphyxiation or inhalation of isoflurane. Both techniques are followed by cervical dislocation. Since it is poss...

Watch this Scientific Journal Video about RNA Isolation from Mouse Pancreas: A Ribonuclease-rich Tissue at JoVE.com

RNA Isolation from Mouse Pancreas: A Ribonuclease-rich Tissue

We report a procedure to isolate RNA with high integrity from the ribonuclease rich mouse pancreas.

Isolation of high-quality RNA from ribonuclease-rich tissue such as mouse pancreas presents a challenge.  As a primary function of the pancreas is to aid ...

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JoVE Journal

Biology

27.4K Görüntüleme.  The Ohio State University. We report a procedure to isolate RNA with high integrity from the ribonuclease rich mouse pancreas.

Video: RNA Isolation from Mouse Pancreas: A Ribonuclease-rich Tissue

Neuronal Nuclei Isolation from Human Postmortem Brain Tissue

Neurons in the human brain become postmitotic largely during prenatal development, and thus maintain their nuclei throughout the full lifespan. However, little is known about changes in neuronal chromatin and nuclear organization during the course of development and aging, or in chronic neuropsychiatric disease. However, to date most chromatin and DNA based assays (other than FISH) lack single cell resolution. To this end, the considerable cellular heterogeneity of brain tissue poses a significant limitation, because typically various subpopulations of neurons are intermingled with different types of glia and other non-neuronal cells. One possible solution would be to grow cell-type specific cultures, but most CNS cells, including neurons, are ex vivo sustainable, at best, for only a few weeks and thus would provide an incomplete model for epigenetic mechanisms potentially operating across the full lifespan.  Here, we provide a protocol to extract and purify nuclei from frozen (never fixed) human postmortem brain. The method involves extraction of nuclei in hypotonic lysis buffer, followed by ultracentrifugation and immunotagging with anti-NeuN antibody. Labeled neuronal nuclei are then collected separately using fluorescence-activated sorting. This method should be applicable to any brain region in a wide range of species and suitable for chromatin immunoprecipitation studies with site- and modification-specific anti-histone antibodies, and for DNA methylation and other assays. 

The cellular heterogeneity of brain tissue poses a significant limitation for the study of epigenetic markings in chromatin because most assays lack single cell resolution. Neurons typically are intermingled with glia and other non-neuronal cells. We provide a protocol to extract and collect neuronal nuclei from human brain.

Neurons in the human brain become postmitotic largely during prenatal development, and thus maintain their nuclei throughout the full lifespan. However, ...

Isolation of Primary Myofibroblasts from Mouse and Human Colon Tissue

The myofibroblast is a stromal cell of the gastrointestinal (GI) tract that has been gaining considerable attention for its critical role in many GI functions. While several myofibroblast cell lines are commercially available to study these cells in vitro, research results from a cell line exposed to experimental cell culture conditions have inherent limitations due to the overly reductionist nature of the work. Use of primary myofibroblasts offers a great advantage in terms of confirming experimental findings identified in a cell line. Isolation of primary myofibroblasts from an animal model allows for the study of myofibroblasts under conditions that more closely mimic the disease state being studied. Isolation of primary myofibroblasts from human colon tissue provides arguably the most relevant experimental data, since the cells come directly from patients with the underlying disease. We describe a well-established technique that can be utilized to isolate primary myofibroblasts from both mouse and human colon tissue. These isolated cells have been characterized to be alpha-smooth muscle actin and vimentin-positive, and desmin-negative, consistent with subepithelial intestinal myofibroblasts. Primary myofibroblast cells can be grown in cell culture and used for experimental purposes over a limited number of passages.

The myofibroblast is an influential stromal cell of the gastrointestinal tract that regulates important physiologic processes in both normal and disease states. We describe a technique that allows for the isolation of primary myofibroblasts from both mouse and human colon tissue, which can be utilized for in vitro experimentation.

The myofibroblast is  a stromal cell of the gastrointestinal (GI) tract that has been gaining  considerable attention for its critical role in many GI ...

In Vitro Pancreas Organogenesis from Dispersed Mouse Embryonic Progenitors

The pancreas is an essential organ that regulates glucose homeostasis and secretes digestive enzymes. Research on pancreas embryogenesis has led to the development of protocols to produce pancreatic cells from stem cells 1. The whole embryonic organ can be cultured at multiple stages of development 2-4. These culture methods have been useful to test drugs and to image developmental processes. However the expansion of the organ is very limited and morphogenesis is not faithfully recapitulated since the organ flattens. 
We propose three-dimensional (3D) culture conditions that enable the efficient expansion of dissociated mouse embryonic pancreatic progenitors. By manipulating the composition of the culture medium it is possible to generate either hollow spheres, mainly composed of pancreatic progenitors expanding in their initial state, or, complex organoids which progress to more mature expanding progenitors and differentiate into endocrine, acinar and ductal cells and which spontaneously self-organize to resemble the embryonic pancreas. 
We show here that the in vitro process recapitulates many aspects of natural pancreas development. This culture system is suitable to investigate how cells cooperate to form an organ by reducing its initial complexity to few progenitors. It is a model that reproduces the 3D architecture of the pancreas and that is therefore useful to study morphogenesis, including polarization of epithelial structures and branching. It is also appropriate to assess the response to mechanical cues of the niche such as stiffness and the effects on cell&#180;s tensegrity.

In Vitro Pancreas Organogenesis from Dispersed Mouse Embryonic Progenitors

The three-dimensional culture method described in this protocol recapitulates pancreas development from dispersed embryonic mouse pancreas progenitors, including their substantial expansion, differentiation and morphogenesis into a branched organ. This method is amenable to imaging, functional interference and manipulation of the niche.

The pancreas is an essential organ that regulates glucose homeostasis and secretes digestive enzymes. Research on pancreas embryogenesis has led to the ...

Protein Isolation from the Developing Embryonic Mouse Heart Valve Region

Western blot analysis is a commonly employed technique for detecting and quantifying protein levels. However, for small tissue samples, this analysis method may not be sufficiently sensitive to detect a protein of interest. To overcome these difficulties, we examined protocols for obtaining protein from adult human cardiac valves and modified these protocols for the developing early embryonic mouse counterparts. In brief, the mouse embryonic aortic valve regions, including the aortic valve and surrounding aortic wall, are collected in the minimal possible volume of a Tris-based lysis buffer with protease inhibitors. If required based on the breeding strategy, embryos are genotyped prior to pooling four embryonic aortic valve regions for homogenization. After homogenization, an SDS-based sample buffer is used to denature the sample for running on an SDS-PAGE gel and subsequent western blot analysis. Although the protein concentration remains too low to quantify using spectrophotometric protein quantification assays and have sample remaining for subsequent analyses, this technique can be used to successfully detect and semi-quantify phosphorylated proteins via western blot from pooled samples of four embryonic day 13.5 mouse aortic valve regions, each of which yields approximately 1 &#956;g of protein. This technique will be of benefit for studying cell signaling pathway activation and protein expression levels during early embryonic mouse valve development.

The analysis of protein expression in young embryonic mouse valves has been hampered by the limited tissue available. This manuscript provides a protocol for preparing protein from developing embryonic mouse valve regions for western blot analysis.

Western blot analysis is a commonly employed technique for detecting and quantifying protein levels. However, for small tissue samples, this analysis ...

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

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

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

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

Isolation and Culture of Primary Mouse Keratinocytes from Neonatal and Adult Mouse Skin

The keratinocyte (KC) is the predominant cell type in the epidermis, the outermost layer of the skin. Epidermal KCs play a critical role in providing skin defense by forming an intact skin barrier against environmental insults, such as UVB irradiation or pathogens, and also by initiating an inflammatory response upon those insults. Here we describe methods to isolate KCs from neonatal mouse skin and from adult mouse tail skin. We also describe culturing conditions using defined growth supplements (dGS) in comparison to chelexed fetal bovine serum (cFBS). Functionally, we show that both neonatal and adult KCs are highly responsive to high calcium-induced terminal differentiation, tight junction formation and stratification. Additionally, cultured adult KCs are susceptible to UVB-triggered cell death and can release large amounts of TNF upon UVB irradiation. Together, the methods described here will be useful to researchers for the setup of in vitro models to study epidermal biology in the neonatal mouse and/or the adult mouse.

Epidermal keratinocytes form a functional skin barrier and are positioned at the front line of host defense against external environmental insults. Here we describe methods for isolation and primary culture of epidermal keratinocytes from neonatal and adult mouse skin, and induction of terminal differentiation and UVB-triggered inflammatory response from keratinocytes.

The keratinocyte (KC) is the predominant cell type in the epidermis, the outermost layer of the skin. Epidermal KCs play a critical role in providing skin ...

Nuclei Isolation from Whole Tissue using a Detergent and Enzyme-Free Method

High-throughput transcriptome and epigenome profiling requires preparation of a single cell or single nuclei suspension. Preparation of the suspension with&#160;intact cell or nuclei involves dissociation and permeabilization, steps that can introduce unwanted noise and undesirable damage. Particularly, certain cell-types such as neurons are challenging to dissociate into individual cells. Additionally, permeabilization of the cellular membrane to release nuclei requires optimization by trial-and-error, which can be time consuming, labor intensive and financially nonviable. To enhance the robustness and reproducibility of sample preparation for high-throughput sequencing, we describe a rapid enzyme and detergent-free column-based nuclei isolation method. The protocol enables efficient isolation of nuclei from the entire zebrafish brain within 20 minutes. The isolated nuclei display intact nuclear morphology and low propensity to aggregate. Further, flow cytometry allows nuclei enrichment and clearance of cellular debris for downstream application. The protocol, which should work on soft tissues and cultured cells, provides a simple and accessible method for sample preparation that can be utilized for high-throughput profiling, simplifying the steps required for successful single-nuclei RNA-seq and ATAC-seq experiments.

Single nuclei isolation relies on dissociation and detergent-based permeabilization of the cell membrane, steps that need optimization and are prone to introducing technical artifacts. We demonstrate a detergent and enzyme-free protocol for rapid isolation of intact nuclei directly from whole tissue, yielding nuclei suitable for single-nucleus RNA-seq (snRNA-Seq) or ATAC-seq.

High-throughput transcriptome and epigenome profiling requires preparation of a single cell or single nuclei suspension. Preparation of the suspension ...

Tissue Collection and RNA Extraction from the Human Osteoarthritic Knee Joint

Osteoarthritis (OA) is a chronic and degenerative joint disease most often affecting the knee. As there is currently no cure, total knee arthroplasty (TKA) is a common surgical intervention. Experiments using primary human OA tissues obtained from TKA provide the capability to investigate disease mechanisms ex vivo. While OA was previously thought to impact mainly the cartilage, it is now known to impact multiple tissues in the joint. This protocol describes patient selection, sample processing, tissue homogenization, RNA extraction, and quality control (based on RNA purity, integrity, and yield) from each of seven unique tissues to support disease mechanism investigation in the knee joint. With informed consent, samples were obtained from patients undergoing TKA for OA. Tissues were dissected, washed, and stored within 4 h of surgery by flash freezing for RNA or formalin fixation for histology. Collected tissues included articular cartilage, subchondral bone, meniscus, infrapatellar fat pad, anterior cruciate ligament, synovium, and vastus medialis oblique muscle. RNA extraction protocols were tested for each tissue type. The most significant modification involved the method of disintegration used for low-cell, high-matrix, hard tissues (considered as cartilage, bone, and meniscus) versus relatively high-cell, low-matrix, soft tissues (considered as fat pad, ligament, synovium, and muscle). It was found that pulverization was appropriate for hard tissues, and homogenization was appropriate for soft tissues. A proclivity for some subjects to yield higher RNA integrity number (RIN) values than other subjects consistently across multiple tissues was observed, suggesting that underlying factors such as disease severity may impact RNA quality. The ability to isolate high-quality RNA from primary human OA tissues provides a physiologically relevant model for sophisticated gene expression experiments, including sequencing, that can lead to clinical insights that are more readily translated to patients.

Primary tissues obtained from patients following total knee arthroplasty provide an experimental model for osteoarthritis research with maximal clinical translatability. This protocol describes how to identify, process, and isolate RNA from seven unique knee tissues to support mechanistic investigation in human osteoarthritis.

Osteoarthritis (OA) is a chronic and degenerative joint disease most often affecting the knee. As there is currently no cure, total knee arthroplasty ...

Nuclei Isolation from Adult Mouse Kidney for Single-Nucleus RNA-Sequencing

The kidneys regulate diverse biological processes such as water, electrolyte, and acid-base homeostasis. Physiological functions of the kidney are executed by multiple cell types arranged in a complex architecture across the corticomedullary axis of the organ. Recent advances in single-cell transcriptomics have accelerated the understanding of cell type-specific gene expression in renal physiology and disease. However, enzyme-based tissue dissociation protocols, which are frequently utilized for single-cell RNA-sequencing (scRNA-seq), require mostly fresh (non-archived) tissue, introduce transcriptional stress responses, and favor the selection of abundant cell types of the kidney cortex resulting in an underrepresentation of cells of the medulla.
Here, we present a protocol that avoids these problems. The protocol is based on nuclei isolation at 4 &#176;C from frozen kidney tissue. Nuclei are isolated from a central piece of the mouse kidney comprised of the cortex, outer medulla, and inner medulla. This reduces the overrepresentation of cortical cells typical for whole-kidney samples for the benefit of medullary cells such that data will represent the entire corticomedullary axis at sufficient abundance. The protocol is simple, rapid, and adaptable and provides a step towards the standardization of single-nuclei transcriptomics in kidney research.

Here, we present a protocol to isolate high-quality nuclei from frozen mouse kidneys that improve the representation of medullary kidney cell types and avoids the gene expression artifacts from enzymatic tissue dissociation.

The kidneys regulate diverse biological processes such as water, electrolyte, and acid-base homeostasis. Physiological functions of the kidney are ...

Plastoglobule Lipid Droplet Isolation from Plant Leaf Tissue and Cyanobacteria

Plastoglobule lipid droplets are a dynamic sub-compartment of plant chloroplasts and cyanobacteria. Found ubiquitously among photosynthetic species, they are believed to serve a central role in the adaptation and remodeling of the thylakoid membrane under rapidly changing environmental conditions. The capacity to isolate plastoglobules of high purity has greatly facilitated their study through proteomic, lipidomic, and other methodologies. With plastoglobules of high purity and yield, it is possible to investigate their lipid and protein composition, enzymatic activity, and protein topology, among other possible molecular characteristics. This article presents a rapid and effective protocol for the isolation of plastoglobules from chloroplasts of plant leaf tissue and presents methodological variations for the isolation of plastoglobules and related lipid droplet structures from maize leaves, the desiccated leaf tissue of the resurrection plant, Eragrostis nindensis, and the cyanobacterium, Synechocystis sp. PCC 6803. Isolation relies on the low density of these lipid-rich particles, which facilitates their purification by sucrose density flotation. This methodology will prove valuable in the study of plastoglobules from diverse species.

A fast and efficient protocol is presented for the isolation of plastoglobule lipid droplets associated with various photosynthetic organisms. The successful preparation of isolated plastoglobules is a crucial first step that precedes detailed molecular investigations such as proteomic and lipidomic analyses.

Plastoglobule lipid droplets are a dynamic sub-compartment of plant chloroplasts and cyanobacteria. Found ubiquitously among photosynthetic species, they ...