Name: a method for mouse pancreatic islet isolation and intracellular camp determination
Uploaded: 2014-06-25T13:00:00
Description: Watch this Scientific Journal Video about A Method for Mouse Pancreatic Islet Isolation and Intracellular cAMP Determination at JoVE.com

We would like to thank Renee L. Pasker and Harpreet K. Brar for expert technical assistance on the protocols described in this work. Furthermore, we would like to acknowledge the mentoring of Christopher B. Newgard at Duke University and Alan D. Attie at the University of Wisconsin-Madison, along with the support of their laboratory members, which allowed us the time and support necessary to optimize the described protocols. In particular, we thank Hans Hohmeier, Danhong Lu, and Helena Winfield in the Newgard Laboratory and Mary Rabaglia in the Attie Laboratory for productive discussions and advice. This work was supported by NIH grant DK080845 and Juvenile Diabetes 594 
Research Foundation grant 17-2011-608 (to M.E.K.)

All animal experiments were executed in compliance with all relevant guidelines, regulations and regulatory agencies. The protocol being demonstrated was performed under the guidance and approval of the Institutional Animal Care and Use Committee (IACUC) of the University of Wisconsin-Madison.
1. Preparation of Solutions
<ol>
	<li>The method of euthanasia in this protocol is exsanguination under Avertin anesthesia (for a review of alternatives, see Discussion). To make Avertin, add 0.625 g (...

<ol>
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S., Rorsman, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+exposure+of+mouse+pancreatic+islets+to+oleate+or+palmitate+results+in+reduced+glucose+induced+somatostatin+and+oversecretion+of+glucagon.">Long-term exposure of mouse pancreatic islets to oleate or palmitate results in reduced glucose induced somatostatin and oversecretion of glucagon.</a> Diabetologia. 51, 1689-1693 (2008).</li><li>Fueger, P. T., Hernandez, A. M., Chen, Y. C., Colvin, E. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessing+Replication+and+Beta+Cell+Function+in+Adenovirally-transduced+Isolated+Rodent+Islets.">Assessing Replication and Beta Cell Function in Adenovirally-transduced Isolated Rodent Islets.</a> J Vis Exp. , (2012).</li><li>Szot, G. L., Koudria, P., Bluestone, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murine+pancreatic+islet+isolation.">Murine pancreatic islet isolation.</a> J Vis Exp. , (2007).</li><li>Szot, G. L., Koudria, P., Bluestone, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transplantation+of+pancreatic+islets+into+the+kidney+capsule+of+diabetic+mice.">Transplantation of pancreatic islets into the kidney capsule of diabetic mice.</a> J Vis Exp. , (2007).</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> J Vis Exp. , (2011).</li><li>Kimple, M. 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With the prevalence of diabetes projected to affect 7.7% of the world&#8217;s population, the requirement of novel research techniques is imperative to both understand and treat diabetes18. The present islet isolation is a well-established protocol used for in vitro experimentation and has been presented previously with slight modifications11,14,16. Although insulin secretion is a common downstream application for isolated islets, focusing on upstream constituents, such as cAMP, may help de...

The strict maintenance of euglycemia is imperative to prevent morbidities such as neuropathy, nephropathy, and retinopathy, which are all hallmarks of the pathology of uncontrolled type 1 and 2 diabetes1. Reduced &#946;-cell function and mass in both type 1 and 2 diabetes perturb blood glucose concentrations2. Whereas immune-mediated type 1 diabetes results from a devastating loss of insulin-producing &#946;-cells, impaired &#946;-cell insulin secretion and peripheral insulin signaling in type 2 diabetes together promote hyperglycemia, dyslipidemia, and increased hepatic glucose production, which eventually results in both loss of &#946;-cell mass and insulin secretory capacity from individual &#946;-cells3. Understanding the underlying &#946;-cell mechanisms in the progression of type 1 and 2 diabetes will hopefully give rise to novel therapies to prevent and treat these diseases.
In vitro tissue culture models, such as the INS-1 and MIN6 immortalized &#946;-cell lines, can be useful tools for understanding specific &#946;-cell functions. However, the interactions among the different cell types within the islet may themselves regulate &#946;-cell function. For example, the paracrine influence of glucagon (released from &#945;-cells) and somatostatin (released from &#948;-cells) in increasing and decreasing insulin secretion, respectively, demonstrates the importance of cell cell proximity in the endocrine response4. Moreover, gap junctions between &#946;-cells potentiate the release of insulin5. Furthermore, although strides have been made in generating insulinoma lines that better replicated the physiological response of isolated islets to glucose (e.g., the INS-1- derived 832/13 and 832/3 cell lines), their glucose responsiveness still differs from normal rat islets6,7. Moreover, the response of these clonal insulinoma cell lines to glucagon-like peptide-1 (GLP-1) agonists can differ dramatically from one another, as well as from normal islets6. Therefore, immortalized cell lines may not represent the best model for assaying agents that impact on cAMP production.
In contrast to the insulinoma-derived cell lines, studying &#946;-cell function solely in whole animal models offers its own set of complications. One of the biggest challenges in working with endocrine tissue is measuring the precise concentration of hormone released. Specifically, the liver plays a major role metabolizing insulin, and the pancreas blood flow goes directly to the liver. Thus, a plasma insulin measurement may not accurately portray the amounts of insulin being secreted from the pancreas itself or the impact of different treatments on the rate of insulin secretion8. Furthermore, renal metabolism of glucagon may limit the reliability of glucagon output from islet &#945;-cells9. Therefore, isolating primary mouse islets for in vitro experimentation provides a more precise understanding of how the islet is responding to specific stimuli to complement measurements made in vivo.
The present protocol for the isolation of mouse islets is a well-established protocol used by a number of groups (with slight modifications that may help to increase success)10,11. In addition, the determination of cAMP production allows for a direct read-out of the incretin responsiveness of the &#946;-cells. In conjunction with cAMP measurement, protein content and insulin secretion can also be quantified from the same cAMP sample prep, helping to determine whether a defect in &#946;-cell function lies proximal or distal to cAMP10. The final cAMP content and insulin secretion application in this protocol can be a very powerful tool for understanding the influence of pharmaceutical and dietary constituents, among others, on cAMP and insulin secretion. In addition to stimulation from glucose alone, other compounds can be used to measure changes in cAMP and insulin secretion10,11.
Finally, although insulin is the primary hormone we assay from isolated islets, other hormones, such as glucagon and somatostatin, as well as cytokines, eicosanoids, and cyclic adenosine monophosphate, can also be measured, either by a transient stimulation assay or by quantification of their levels in culture medium12. Finally, although outside of the scope of this manuscript, islet isolation with the described collagenase isolation method allows for islet preservation so that many other downstream applications may be pursued, such as islet transplantation, RNA isolation for quantitative real time PCR or microarray analyses, protein isolation for Western blotting, islet embedding and immunofluorescent imaging, and [3H]-thymidine incorporation as a measure of islet cell replication, some of which have been described in previous JoVE articles13-16. Overall, following the islet isolation procedure described in the protocol may provide a researcher with important and useful information for developing therapies and promoting drug discovery aimed at enhancing &#946;-cell function.

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			<td height="64" style="height:64px;width:235px;">Collagenase: Collagenase from Clostridium histolyticum suitable for isolating active islets</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td style="width:136px;">C7657</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Ficoll 400</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td>F9378</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Hanks Balanced Salt Solution 10X</td>
			<td style="width:131px;">Invitrogen (Gibco)</td>
			<td>14065-056</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Hepes</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td>H3375</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">RPMI 1640 (powder)</td>
			<td style="width:131px;">Invitrogen (Gibco)</td>
			<td style="width:136px;">31800-022</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Albumin from Bovine Serum (BSA)</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td>A7888</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">3/0 Silk Suture Thread</td>
			<td style="width:131px;">Fine Science Tools</td>
			<td>18020-30</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Dumont #5 Forceps</td>
			<td style="width:131px;">Fine Science Tools</td>
			<td>11251-10</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">0.8 mm Forceps&#160;&#160;</td>
			<td style="width:131px;">Fine Science Tools&#160;&#160;</td>
			<td style="width:136px;">11050-10</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Curved Scissors</td>
			<td style="width:131px;">Fine Science Tools&#160;&#160;</td>
			<td style="width:136px;">14061-10</td>
		</tr>
		<tr height="64">
			<td height="64" style="height:64px;width:235px;">Vannas-T&#252;bingen Spring Scissors - Straight/Sharp/8.5 cm/5 mm Cutting Edge</td>
			<td style="width:131px;">Fine Science Tools</td>
			<td style="width:136px;">15003-08</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Dissecting Scissors</td>
			<td style="width:131px;">Fine Science Tools&#160;&#160;</td>
			<td style="width:136px;">14002-14</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">5ml BD Luer-Lok Syringe</td>
			<td style="width:131px;">BD</td>
			<td style="width:136px;">309646</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">1ml BD syringe</td>
			<td style="width:131px;">BD</td>
			<td style="width:136px;">309628</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">30 G BD Needle 1/2&#34; Length</td>
			<td style="width:131px;">BD</td>
			<td style="width:136px;">305106</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">27 G BD Needle 1/2&#34; Length</td>
			<td style="width:131px;">BD</td>
			<td style="width:136px;">305109</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Sharpening Stone</td>
			<td style="width:131px;">Fine Science Tools</td>
			<td style="width:136px;">29008-01</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">2-2-2 tribromoethanol</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td style="width:136px;">T48402-25G</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">2-methyl-2-butanol</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td>240486-100mL</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Sodium Chloride (NaCl)</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td>S9888</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Potassium Chloride</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td>P3911</td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:235px;">Monopotassium Phosphate (KH2PO4)</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td style="width:136px;">P0662</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:235px;">Sodium Bicarbonate (NaCHO3)</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td style="width:136px;">S6014</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:235px;">CaCl2 *2H2O</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td style="width:136px;">C3881</td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:235px;">MgSO4 *7H2O</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td style="width:136px;">M9397</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">Penicillin-Streptomycin</td>
			<td style="width:131px;">Invitrogen (Gibco)</td>
			<td style="width:136px;">15140-122</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:235px;">Heat Inactivated Fetal Bovine Serum (H.I. FBS)</td>
			<td style="width:131px;">Fisher Scientific</td>
			<td style="width:136px;">SH30088.03HI</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:235px;">3-Isobutyl-1-methylxanthine (IBMX)</td>
			<td style="width:131px;">Sigma-Aldrich</td>
			<td style="width:136px;">5879-100MG</td>
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a method for mouse pancreatic islet isolation and intracellular camp determination

Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing prevalence of diabetes, both immune-mediated type 1 and obesity-linked type 2, studies aimed at delineating diabetes pathophysiology and therapeutic mechanisms are of critical importance. The &#946;-cells of the pancreatic islets of Langerhans are responsible for appropriately secreting insulin in response to elevated blood glucose concentrations. In addition to glucose and other nutrients, the &#946;-cells are also stimulated by specific hormones, termed incretins, which are secreted from the gut in response to a meal and act on &#946;-cell receptors that increase the production of intracellular cyclic adenosine monophosphate (cAMP). Decreased &#946;-cell function, mass, and incretin responsiveness are well-understood to contribute to the pathophysiology of type 2 diabetes, and are also being increasingly linked with type 1 diabetes. The present mouse islet isolation and cAMP determination protocol can be a tool to help delineate mechanisms promoting disease progression and therapeutic interventions, particularly those that are mediated by the incretin receptors or related receptors that act through modulation of intracellular cAMP production. While only cAMP measurements will be described, the described islet isolation protocol creates a clean preparation that also allows for many other downstream applications, including glucose stimulated insulin secretion, [3H]-thymidine incorporation, protein abundance, and mRNA expression.

To ensure a high islet yield during isolation, surgical techniques outlined in the protocol should be followed closely. Although the techniques presented here will be tailored to each laboratory, there are a few critical steps that will lead to a successful isolation. In order to make the common bile duct easily accessible, it is recommended that the organs be displaced to the right side of the mouse (Figure 1). Moreover, this will allow the pancreas to inflate with a smaller amount of resistance since t...

Watch this Scientific Journal Video about A Method for Mouse Pancreatic Islet Isolation and Intracellular cAMP Determination at JoVE.com

A Method for Mouse Pancreatic Islet Isolation and Intracellular cAMP Determination

Assaying in vitro &#946;-cell function using isolated mouse islets of Langerhans is an important component in the study of diabetes pathophysiology and therapeutics. While many&#160;downstream applications are available, this protocol specifically describes the measurement of intracellular cyclic adenosine monophosphate (cAMP) as an essential parameter determining &#946;-cell function.

Uncontrolled glycemia is a hallmark of diabetes mellitus and promotes morbidities like neuropathy, nephropathy, and retinopathy. With the increasing ...

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Research

JoVE Journal

Biology

Murine Pancreatic Islet Isolation

Human Pancreatic Islet Isolation: Part I: Digestion and Collection of Pancreatic Tissue

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients 1, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet mass is important for successful islet transplantation. However, donor characteristic, organ procurement and preservation affect the isolation outcome 2. At University of Illinois at Chicago (UIC) we have developed a successful isolation protocol with an improved purification gradient 3. The program started in January 2004, and more than 300 isolations were performed up to November 2008. The pancreata were sent in cold preservation solutions (UW, University of Wisconsin or HTK, Histidine-Tryptophan Ketoglutarate) 4-7 to the Cell Isolation Laboratory at UIC for islet isolation. Pancreatic islets were isolated using the UIC method, which is a modified version of the method originally described by Ricordi et al 8. Briefly, after cleaning the pancreas from the surrounding tissue, it was perfused with enzyme solution (Serva Collagenase + Neutral Protease or Sigma V enzyme). The distended pancreas was then transferred to the Ricordi digestion chamber, connected to a modified, closed circulation tubing system, and warmed up to 37&deg;C. During the digestion, the chamber was shaken gently. Samples were taken continuously to monitor the digestion progress. Once free islets were detected under the microscope, the digestion was stopped by flushing cold (4&deg;C) RPMI dilution solution (Mediatech, Herndon, VA) into the circulation system to dilute the enzyme. After being collected and washed in M199 media supplemented with human albumin, the tissue was sampled for pre-purification count and incubated with UW solution before purification. Purification process will be described in Part II: Purification and Culture of Human Islets.

Achieving high quality and appropriate quantity of human islets is one of the prominent prerequisites for successful islet transplantation. In this video, we describe step by step the procedures for human pancreatic islet isolation (part I: digestion and collection of pancreatic tissue) using a modified automated method.

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of ...

Human Pancreatic Islet Isolation: Part II: Purification and Culture of Human Islets

Management of Type 1 diabetes is burdensome, both to the individual and society, costing over 100 billion dollars annually. Despite the widespread use of glucose monitoring and new insulin formulations, many individuals still develop devastating secondary complications. Pancreatic islet transplantation can restore near normal glucose control in diabetic patients 1, without the risk of serious hypoglycemic episodes that are associated with intensive insulin therapy. Providing sufficient islet mass is important for successful islet transplantation. However, donor characteristics, organ procurement and preservation affect the isolation outcome 2. At University of Illinois at Chicago (UIC) we developed a successful isolation protocol with an improved purification gradient 3. The program started in January 2004 and more than 300 isolations were performed up to November 2008. The pancreata were sent in cold preservation solutions (UW, University of Wisconsin or HTK, Histidine-Tryptophan Ketoglutarate) 4-7 to the Cell Isolation Laboratory at UIC for islet isolation. Pancreatic islets were isolated using the UIC method, which is a modified version of the method originally described by Ricordi et al 8. As described in Part I: Digestion and Collection of Pancreatic Tissue, human pancreas was trimmed, cannulated, perfused, and digested. After collection and at least 30 minutes of incubation in UW solution, the tissue was loaded in the cell separator (COBE 2991, Cobe, Lakewood, CO) for purification 3. Following purification, islet yield (expressed as islet equivalents, IEQ), tissue volume, and purity was determined according to standard methods 9. Isolated islets were cultured in CMRL-1066 media (Mediatech, Herndon, VA), supplemented with 1.5% human albumin, 0.1% insulin-transferrin-selenium (ITS), 1 ml of Ciprofloxacin, 5 ml o f 1M HEPES, and 14.5 ml of 7.5% Sodium Bicarbonate in T175 flasks at 37&deg;C overnight culture before islets were transplanted or used for research.

Achieving high quality and appropriate quantity of human islets is one of the prominent prerequisites for successful islet transplantation. In this video, we describe step by step the procedures for human pancreatic islet isolation (part II: purification and culture of human islets) using a modified automated method.

Computer-assisted Large-scale Visualization and Quantification of Pancreatic Islet Mass, Size Distribution and Architecture

The pancreatic islet is a unique micro-organ composed of several hormone secreting endocrine cells such as beta-cells (insulin), alpha-cells (glucagon), and delta-cells (somatostatin) that are embedded in the exocrine tissues and comprise 1-2% of the entire pancreas. There is a close correlation between body and pancreas weight. Total beta-cell mass also increases proportionately to compensate for the demand for insulin in the body. What escapes this proportionate expansion is the size distribution of islets. Large animals such as humans share similar islet size distributions with mice, suggesting that this micro-organ has a certain size limit to be functional. The inability of large animal pancreata to generate proportionately larger islets is compensated for by an increase in the number of islets and by an increase in the proportion of larger islets in their overall islet size distribution. Furthermore, islets exhibit a striking plasticity in cellular composition and architecture among different species and also within the same species under various pathophysiological conditions. In the present study, we describe novel approaches for the analysis of biological image data in order to facilitate the automation of analytic processes, which allow for the analysis of large and heterogeneous data collections in the study of such dynamic biological processes and complex structures. Such studies have been hampered due to technical difficulties of unbiased sampling and generating large-scale data sets to precisely capture the complexity of biological processes of islet biology. Here we show methods to collect unbiased "representative" data within the limited availability of samples (or to minimize the sample collection) and the standard experimental settings, and to precisely analyze the complex three-dimensional structure of the islet. Computer-assisted automation allows for the collection and analysis of large-scale data sets and also assures unbiased interpretation of the data. Furthermore, the precise quantification of islet size distribution and spatial coordinates (i.e. X, Y, Z-positions) not only leads to an accurate visualization of pancreatic islet structure and composition, but also allows us to identify patterns during development and adaptation to altering conditions through mathematical modeling. The methods developed in this study are applicable to studies of many other systems and organisms as well.

Novel computer-assisted methods of large-scale procurement and analysis of immunohistochemically stained pancreatic specimens are described: (1) Virtual Slice capture of the entire section; (2) Mass analysis of large-scale data; (3) Reconstruction of 2D Virtual Slices; (4) 3D islet mapping; and (5) Mathematical analysis.

The pancreatic islet is a unique micro-organ composed of several hormone secreting endocrine cells such as beta-cells (insulin), alpha-cells (glucagon), ...

Mouse Islet of Langerhans Isolation using a Combination of Purified Collagenase and Neutral Protease

The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines to the study of isolated rodent islets. Primary islets offer the distinct advantage that they more faithfully reflect the biology of intracellular signaling pathways and secretory responses. Whereas the method of islet isolation using tissue dissociating enzyme (TDE) preparations has been well established in many laboratories1-4, variations in the consistency of islet yield and quality from any given rodent strain limit the extent and feasibility of primary islet studies. These variations often occur as a result of the crude partially purified TDEs used in the islet isolation procedure; TDEs frequently exhibit lot-to-lot variations in activity and often require adjustments to the dose of enzyme used. A small number of reports have used purified TDEs for rodent cell isolations5, 6, but the practice is not widespread despite the routine use and advantages of purified TDEs for human islet isolations. In collaboration with VitaCyte, LLC (Indianapolis, IN), we developed a modified mouse islet isolation protocol based on that described by Gotoh7, 8, in which the TDEs are perfused directly into the pancreatic duct of mice, followed by crude tissue fractionation through a Histopaque gradient9, and isolation of purified islets. A significant difference in our protocol is the use of purified collagenase (CIzyme MA) and neutral protease (CIzyme BP) combination. The collagenase was characterized by the use of a6 fluorescence collagen degrading activity (CDA) assay that utilized fluorescently labeled soluble calf skin fibrils as substrate6. This substrate is more predictive of the kinetics of collagen degradation in the tissue matrix because it relies on native collagen as the substrate. The protease was characterized with a sensitive fluorescent kinetic assay10. Utilizing these improved assays along with more traditional biochemical analysis enable the TDE to be manufactured more consistently, leading to improved performance consistency between lots. The protocol described in here was optimized for maximal islet yield and optimal islet morphology using C57BL/6 mice. During the development of this protocol, several combinations of collagenase and neutral proteases were evaluated at different concentrations, and the final ratio of collagenase:neutral protease of 35:10 represents enzyme performance comparable to Sigma Type XI. Because significant variability in average islet yields from different strains of rats and mice have been reported, additional modifications of the TDE composition should be made to improve the yield and quality of islets recovered from different species and strains.

A detailed description of mouse islet isolation is described using the technique of in situ pancreatic ductal cannulation and perfusion of a combination of purified collagenase and neutral protease.

The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines ...

Isolation and Culture of Mouse Primary Pancreatic Acinar Cells

This protocol permits rapid isolation (in less than 1 hr) of murine pancreatic acini, making it possible to maintain them in culture for more than one week. More than 20 x 106 acinar cells can be obtained from a single murine pancreas. This protocol offers the possibility to independently process as many as 10 pancreases in parallel. Because it preserves acinar architecture, this model is well suited for studying the physiology of the exocrine pancreas in vitro in contrast to cell lines established from pancreatic tumors, which display many genetic alterations resulting in partial or total loss of their acinar differentiation.

In this publication, we describe a rapid and convenient procedure for isolating and culturing primary pancreatic acinar cells from the murine pancreas. This method constitutes a valuable approach to study the physiology of fresh primary normal/untransformed exocrine pancreatic cells.

This protocol permits rapid isolation (in less than 1 hr) of murine pancreatic acini, making it possible to maintain them in culture for more than one ...

Near Infrared (NIr) Light Increases Expression of a Marker of Mitochondrial Function in the Mouse Vestibular Sensory Epithelium

Strategies for attenuating decline in balance function with increasing age are predominantly focused on physical therapies including balance tasks and exercise. However, these approaches do not address the underlying causes of balance decline. Using mice, the impact of near infrared light (NIr) on the metabolism of cells in the vestibular sensory epithelium was assessed. Data collected shows that this simple and safe intervention may protect these vulnerable cells from the deleterious effects of natural aging. mRNA was extracted from the isolated peripheral vestibular sensory epithelium (crista ampullaris and utricular macula) and subsequently transcribed into a cDNA library. This library was then probed for the expression of ubiquitous antioxidant (SOD-1). Antioxidant gene expression was then used to quantify cellular metabolism. Using transcranial delivery of NIr in young (4 weeks) and older (8 - 9 months) mice, and a brief treatment regime (90 sec/day for 5 days), this work suggests NIr alone may be sufficient to improve mitochondrial function in the vestibular sensory epithelium. Since there are currently no available, affordable, non-invasive methods of therapy to improve vestibular hair cell function, the application of external NIr radiation provides a potential strategy to counteract the impact of aging on cellular metabolism inthe vestibular sensory epithelium.

Near Infrared NIr Light Increases Expression of a Marker of Mitochondrial Function in the Mouse Vestibular Sensory Epithelium

Mitochondrial dysfunction is a hallmark of cellular senescence. This paper uses non-invasive near-infrared (NIr) treatment to improve mitochondrial function in the aging mouse vestibular sensory epithelium.

Strategies for attenuating decline in balance function with increasing age are predominantly focused on physical therapies including balance tasks and ...

Filtration Isolation of Nucleic Acids:  A Simple and Rapid DNA Extraction Method

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad to extract cellular DNA from whole blood in less than 2 min. The blood specimen is treated with detergent, mixed briefly and applied by pipet to the separation membrane. The lysate wicks into the blotting pad due to capillary action, capturing the genomic DNA on the surface of the separation membrane. The extracted DNA is retained on the membrane during a simple wash step wherein PCR inhibitors are wicked into the absorbent blotting pad. The membrane containing the entrapped DNA is then added to the PCR reaction without further purification. This simple method does not require laboratory equipment and can be easily implemented with inexpensive laboratory supplies. Here we describe a protocol for highly sensitive detection and quantitation of HIV-1 proviral DNA from 100 &#181;l whole blood as a model for early infant diagnosis of HIV that could readily be adapted to other genetic targets.

We describe here a simple and rapid paper-based DNA extraction method of HIV proviral DNA from whole blood detected by quantitative PCR. This protocol can be extended for use in detecting other genetic markers or using alternative amplification methods.

FINA, filtration isolation of nucleic acids, is a novel extraction method which utilizes vertical filtration via a separation membrane and absorbent pad ...

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 ...

A Simple High Efficiency Protocol for Pancreatic Islet Isolation from Mice

Pancreatic islets, also called the Islets of Langerhans, are a cluster of endocrine cells which produces hormones for glucose regulation and other important biological functions. The islets primarily consist of five types of hormone-secreting cells: &#945; cells secrete glucagon, &#946; cells secrete insulin, &#948; cells secrete somatostatin, &#949; cells secrete ghrelin, and PP cells secrete pancreatic polypeptide. Sixty to 80% of the cells in the islets are &#946; cells, which are the most important cell population to study insulin secretion. Pancreatic islets are a crucial model system to study ex vivo insulin secretion. Acquiring high quality islets is of great importance for diabetes research. Most islet isolation procedures require technically difficult to access site of collagenase injection, harsh and complex digestion procedures, and multiple density gradient purification steps. This paper features a simple high yield mouse islet isolation method with detailed descriptions and realistic demonstrations, showing the following specific steps: 1) injection of collagenase P at the ampulla of Vater, a small area joining the pancreatic duct and the common bile duct, 2) enzymatic digestion and mechanical separation of the exocrine pancreas, and 3) a single gradient purification step. The advantages of this method are the injection of digestive enzyme using the more accessible ampulla of Vater, more complete digestion using combination of enzymatic and mechanical approaches, and a simpler single gradient purification step. This protocol produces approximately 250&#8212;350 islets per mouse; and islets are suitable for various ex vivo studies. Possible caveats of this procedure are potentially damaged islets due to enzymatic digestion and/or prolonged gradient incubation, all of which can be largely avoided by careful ad justification of incubation time.

This islet isolation protocol described a novel route of collagenase injection to digest the exocrine tissue and a simplified gradient procedure to purify the islets from mice. It involves enzymatic digestion, gradient separation/purification, and islet hand-picking. Successful isolation can yield 250&#8211;350 high quality and fully functional islets per mouse.