Name: a high-content in vitro pancreatic islet &#946;-cell replication discovery platform
Uploaded: 2016-07-16T15:00:00
Description: Watch this Scientific Journal Video about A High-content In Vitro Pancreatic Islet Î²-cell Replication Discovery Platform at JoVE.com

This work was supported by NIDDK grants DK098143 and DK101530 from the NIH (JPA), Stanford's Spectrum Child Health Research Institute (CHRI) and SPARK (UL1 TR001085, JPA).

This protocol was carried out in accordance with the Institutional Animal Care and Use Committee (IACUC) of Stanford University School of Medicine. The described protocol is scaled for islet isolation from six 250 - 300 g (8 - 9 weeks old) male Sprague Dawley rats, which is sufficient to generate 228 wells of a 384-well plate for islet-cell replication assessment.
1. Material Preparation
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	<li>Prepare coating media prior to initiating islet isolation by collecting the conditioned media of 804G rat b...

<ol>
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Experimental methods for studying the molecular pathways that control &#946;-cell growth and regeneration are important tools for diabetes researchers. Herein, a rat-islet-based screening platform to identify and characterize small-molecule stimulators of &#946;-cell replication is presented.
While most aspects of this protocol are easily performed by experienced researchers, a few steps require particular technique. First, during islet isolation, cannulation of the bile-duct without disruptin...

Diabetes encompasses a collection of disorders sharing the common end-point of disrupted glucose homeostasis. Although the pathogenic mechanisms of diabetes subtypes are distinct, they share the consequence of decreased &#946;-cell mass, i.e., loss of insulin production capacity1,2. Presently, diabetes treatment strategies rely upon chronic administration of exogenous insulin, pharmacologic stimulation of insulin production or enhancement of insulin sensitivity, and rarely, the transplantation of pancreatic islets or whole pancreas3,4. Regrettably, the success of these strategies is short-lived and/or fails to sufficiently recapitulate the function of endogenous insulin production. Despite the utility of developing a method to stimulate &#946;-cell regeneration, no such approach exists. Consequently, a major diabetes research goal is to develop methods to generate new &#946;-cells or to expand endogenous &#946;-cell mass5. Although &#946;-cell regeneration from renewable sources such as embryonic stem cells is advancing, safety and efficiency concerns make the pursuit of alternative strategies, including expansion of mature &#946;-cells, a priority6,7. Importantly, the predominant source of new &#946;-cells in vivo is pre-existing &#946;-cells rather than specialized progenitor cells8,9. Although &#946;-cells appear to have limited replication capacity, a small increase in &#946;-cell mass (~ 30%) may be sufficient to restore glucose homeostasis in many diabetics. Furthermore, in situ pharmacologic stimulation of &#946;-cell mass is a potentially inexpensive and scalable treatment strategy. Herein a high-content screening method for identifying and characterizing small molecules that stimulate &#946;-cell growth is presented.
A variety of in vitro experimental methods may be used to identify gene products and/or molecules that promote primary &#946;-cell replication. Early efforts for measuring &#946;-cell replication induction used fetal rodent pancreata culture or intact isolated islet cultures to measure [3H] thymidine incorporation, BrdU incorporation or mitotic bodies within the aldehyde-thionine or insulin stained population in response to specific treatment conditions10,11. These in vitro approaches and close variants thereof have several limitations. Prominent deficiencies include (1) the use of fetal cells which, unlike mature &#946;-cells, display a high basal &#946;-cell replication rate and are growth regulated in a distinct manner12; (2) the subjective nature of experimenter-dependent adjudication of &#946;-cell replication events; (3) the labor and time intensive nature of experimenter-dependent counting of &#946;-cell replication events retards experimental throughput; (4) the use of nuclear incorporation/stain/appearance to identify replication events and a non-overlapping cytoplasmic stain to identify &#946;-cells leads to misattribution of proximate non-&#946;-cell replication events to &#946;-cells.
More recently mature primary &#946;-cells have been used to assess the impact of transgene over-expression as well as gene product or compound treatment on &#946;-cell replication13-16. However, these studies have also relied upon subjective counting of replication events, cytoplasmic staining- or non-specific methods for &#946;-cell identification and/or labor-intensive steps that limit throughput, e.g., individual slide-well plating of cells or intact islet paraffin embedding and processing17. Notably, an image-based human &#946;-cell replication screening methodology, similar to the one presented herein, has been published18; however, successful use of this assay has not been demonstrated and the use of human islets for primary screening may not be broadly feasible.
An alternative strategy for identifying replication-promoting substances is to assess growth induction of &#946;-cell lines. Initial efforts used transformed &#946;-cell-lines such as min6 cells or INS 832/13-cells14,19-21. However, these cell-lines demonstrate unrestrained growth and bear little resemblance to well-differentiated &#946;-cells22. Consequently, growth-induction capacity is minimal, of unclear relevance and sometimes difficult to recapitulate. An improved strategy for cell-line based screening utilizes &#34;reversibly transformed&#34; cells that are growth arrested in the absence of tetracycline (doxycycline)-dependent SV40 T antigen expression23,24. However, it is unclear whether these cells revert to a &#34;normal&#34; &#946;-cell-like state upon doxycycline removal. Unfortunately, use of these cells has yielded generalized growth-promoting compounds that don&#39;t appear to have immediate utility24. Overall, the use of cell-lines to study growth regulation of a cell-type displaying minimal spontaneous replication activity may have limited applicability.
The &#946;-cell replication screening platform presented herein utilizes mature primary rat &#946;-cells to retain in vivo growth regulation to the extent possible, islet-cell cultures of mixed cell-type composition to enable identification of lineage-restricted growth-promoting activities, multi-well formatting to maximize throughput and automated analysis to eliminate bias and facilitate throughput. Successful use of this platform has enabled identification of several compounds that promote &#946;-cell replication25,26. Additionally, the assay has been used for structure-activity relationship studies and chemical epistasis experiments to provide mechanistic insights into the molecular regulation of &#946;-cell replication. The presented platform was successfully adapted for lentiviral RNAi-based investigation of &#946;-cell replication pathways25. Limitations of the assay include restricted scalability (use of primary cells), use of rodent rather than human islet-cells (though the assay may be adapted for human islet studies), expenses associated with antibody-based imaging and primary islet use, the use of dispersed islets (disrupted islet architecture) to facilitate automated image acquisition and dependence upon the availability of an automated microscope with image acquisition and analysis capability. Although a facile in vivo screening methodology for identifying gene products or compounds that stimulate &#946;-cell regeneration in situ would be ideal, such a platform is not yet available27. Consequently, the described platform is appropriate for researcher interested in investigating most aspects of &#946;-cell replication.

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			<td height="23" style="height:23px;width:364px;">250g male Male Sprague Dawly Rat</td>
			<td style="width:196px;">Charles River</td>
			<td style="width:147px;">Stain # 400</td>
			<td style="width:272px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:364px;">12 cm teeth tisuue forceps</td>
			<td style="width:196px;">Fine Science Tools</td>
			<td style="width:147px;">11021-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">11.5 cm fine scissors</td>
			<td style="width:196px;">Fine Science Tools</td>
			<td style="width:147px;">14058-11</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">14.5 cm surgical scissors</td>
			<td style="width:196px;">Fine Science Tools</td>
			<td style="width:147px;">14001-14</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">16 cm curved forceps</td>
			<td style="width:196px;">Fine Science Tools</td>
			<td style="width:147px;">11003-16</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">12 cm curved hepostat</td>
			<td style="width:196px;">Fine Science Tools</td>
			<td style="width:147px;">13011-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">12 cm scalpel handle</td>
			<td style="width:196px;">Fine Science Tools</td>
			<td style="width:147px;">10003-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Tissue sieve-30 mesh</td>
			<td style="width:196px;">Bellco Glass</td>
			<td style="width:147px;">1985-85000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Cizyme RI, 375,000 CDA units</td>
			<td style="width:196px;">VitaCyte</td>
			<td style="width:147px;">005-1030</td>
			<td></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:364px;">Hanks&#39; Balanced Salt solution (Ca++ and Mg++)</td>
			<td style="width:196px;">Gibco</td>
			<td style="width:147px;">24020-117</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Ketamine HCl (200 mg/20 ml)</td>
			<td style="width:196px;">JHP Pharmaceuticals</td>
			<td style="width:147px;">NDC# 42023-113-10</td>
			<td>to make anesthetic cocktail&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Xylazine (5 g/50 ml)</td>
			<td style="width:196px;">LLOYD</td>
			<td style="width:147px;">NADA# 139-236</td>
			<td>to make anesthetic cocktail&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Histopaque 1077</td>
			<td style="width:196px;">Sigma</td>
			<td style="width:147px;">H-1077</td>
			<td>to make histopaque 1100</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Histopaque 1119</td>
			<td style="width:196px;">Sigma</td>
			<td style="width:147px;">H-1119</td>
			<td>to make histopaque 1100</td>
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			<td height="21" style="height:21px;width:364px;">Newborn Calf Serum 500 ml</td>
			<td style="width:196px;">Hyclone</td>
			<td style="width:147px;">SH30118.03</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Hanks&#39; Balanced Salt solution</td>
			<td style="width:196px;">Hyclone</td>
			<td style="width:147px;">SH30268.01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Dulbecco&#39;s Modified Eagle Medium/Low Glucose&#160;</td>
			<td style="width:196px;">Hyclone</td>
			<td style="width:147px;">SH30021.01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Functionality/Viability Solution&#160;</td>
			<td style="width:196px;">Mediatech</td>
			<td style="width:147px;">99-768-CV</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">RPMI1640 media&#160;</td>
			<td style="width:196px;">Hyclone</td>
			<td style="width:147px;">SH30096.01</td>
			<td>to make conditioned medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">804G rat bladder carcinoma cell-line</td>
			<td style="width:196px;">Available upon request</td>
			<td style="width:147px;"></td>
			<td>to make conditioned medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Fetal Bovine Serum, Qualified</td>
			<td style="width:196px;">Gibco</td>
			<td style="width:147px;">26160</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">GlutaMax-I</td>
			<td style="width:196px;">Gibco</td>
			<td style="width:147px;">35050-061</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Penicillin (5,000 IU/ml/Strptomycin (5 mg/ml)&#160;</td>
			<td style="width:196px;">MP Biomedicals</td>
			<td style="width:147px;">1670049</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Formamide 500 mL</td>
			<td style="width:196px;">Fisher BioReagents</td>
			<td style="width:147px;">BP227-500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Antigen Unmasking Solution 250 mL (PH 6.0)</td>
			<td style="width:196px;">Vector Laboratories</td>
			<td style="width:147px;">H-3300</td>
			<td>to make 0.15 M Sodium Sitrate solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Dextrose, Anhydrous</td>
			<td style="width:196px;">EMD Chemicals</td>
			<td style="width:147px;">DX0145-1</td>
			<td>to make 1 M glucose solution</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:364px;">Nomal Donkey Serum (Powder)</td>
			<td style="width:196px;">Jackson ImmunoResearch</td>
			<td style="width:147px;">017-000-121</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Triton X-100</td>
			<td style="width:196px;">Sigma</td>
			<td style="width:147px;">T8787-100ML</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Mouse anti-human Ki67 antibody</td>
			<td style="width:196px;">BD Biosciences</td>
			<td style="width:147px;">556003</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Goat anti-human PDX-1 antibody</td>
			<td style="width:196px;">R&#38;D Systems</td>
			<td style="width:147px;">AF2419</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Polyclonal Guinea Pig anti-insulin antibody</td>
			<td style="width:196px;">Dako</td>
			<td style="width:147px;">2016-08</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Polyclonal Rabbit anti-glucagon antibody</td>
			<td style="width:196px;">Dako</td>
			<td style="width:147px;">2014-06</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Polyclonal Rabbit anti-somatostatin antibody</td>
			<td style="width:196px;">Dako</td>
			<td style="width:147px;">2011-08</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Polyclonal chicken anti-vimentin antibody</td>
			<td style="width:196px;">abcam</td>
			<td style="width:147px;">ab24525</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Biotin-SP-conjugated, Donkey Anti-Mouse IgG</td>
			<td style="width:196px;">Jackson ImmunoResearch</td>
			<td style="width:147px;">715-065-150</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">StreptAvidin, Alex Flour 488 conjugated&#160;</td>
			<td style="width:196px;">Invitrogen</td>
			<td style="width:147px;">S32354</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Rhodamine-conjugated Donkey Anti-Goat IgG&#160;</td>
			<td style="width:196px;">Jackson ImmunoResearch</td>
			<td style="width:147px;">705-025-147</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Rhodamine-conjugated Donkey Anti-Guinea Pig IgG&#160;</td>
			<td style="width:196px;">Jackson ImmunoResearch</td>
			<td style="width:147px;">706-025-148</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Rhodamine-conjugated Donkey Anti-Rabbit IgG</td>
			<td style="width:196px;">Jackson ImmunoResearch</td>
			<td style="width:147px;">711-025-152</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Cy 5-conjugated Donkey Anti-Guinea Pig IgG&#160;</td>
			<td style="width:196px;">Jackson ImmunoResearch</td>
			<td style="width:147px;">706-175-148</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cy 5-conjugated Donkey Anti-Goat IgG</td>
			<td>Jackson ImmunoResearch</td>
			<td>705-175-147</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Cy 5-conjugated Donkey Anti-Rabbit IgG</td>
			<td>Jackson ImmunoResearch</td>
			<td>711-175-152</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Cy 5-conjugated Donkey Anti-Chicken IgG</td>
			<td>Jackson ImmunoResearch</td>
			<td style="width:147px;">703-175-155</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">DAPI</td>
			<td style="width:196px;">Millipore</td>
			<td style="width:147px;">S7113</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Disposable Reagent Reservoir 25 mL</td>
			<td style="width:196px;">Sorenson BioScience</td>
			<td style="width:147px;">39900</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">384 well, black/clear, tissue culture treated plate</td>
			<td style="width:196px;">BD Falcon</td>
			<td style="width:147px;">353962</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">96 well, black/clear, tissue culture treated plate</td>
			<td style="width:196px;">Costar</td>
			<td style="width:147px;">3603</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Multi-channel pipettor</td>
			<td style="width:196px;">Costar</td>
			<td style="width:147px;">4880</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">12-channel vaccume aspirator</td>
			<td style="width:196px;">Drummond</td>
			<td style="width:147px;">3-000-096</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Cell Scraper</td>
			<td style="width:196px;">Falcon</td>
			<td style="width:147px;">353085</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">Isotemp Water Bath Model 2223&#160;</td>
			<td style="width:196px;">Fisher Scientific</td>
			<td style="width:147px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:364px;">High-content screening instrument: ArrayScan VTI</td>
			<td style="width:196px;">Thermo Scientific</td>
			<td style="width:147px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

a high-content in vitro pancreatic islet &#946;-cell replication discovery platform

Loss of insulin-producing &#946;-cells is a central feature of diabetes. While a variety of potential replacement therapies are being explored, expansion of endogenous insulin-producing pancreatic islet &#946;-cells remains an attractive strategy. &#946;-cells have limited spontaneous regenerative activity; consequently, a crucial research effort is to develop a precise understanding of the molecular pathways that restrain &#946;-cell growth and to identify drugs capable of overcoming these restraints. Herein an automated high-content image-based primary-cell screening method to identify &#946;-cell replication-promoting small molecules is presented. Several, limitations of prior methodologies are surmounted. First, use of primary islet cells rather than an immortalized cell-line maximizes retention of in vivo growth restraints. Second, use of mixed-composition islet-cell cultures rather than a &#946;-cell-line allows identification of both lineage-restricted and general growth stimulators. Third, the technique makes practical the use of primary islets, a limiting resource, through use of a 384-well format. Fourth, detrimental experimental variability associated with erratic islet culture quality is overcome through optimization of isolation, dispersion, plating and culture parameters. Fifth, the difficulties of accurately and consistently measuring the low basal replication rate of islet endocrine-cells are surmounted with optimized immunostaining parameters, automated data acquisition and data analysis; automation simultaneously enhances throughput and limits experimenter bias. Notable limitations of this assay are the use of dispersed islet cultures which disrupts islet architecture, the use of rodent rather than human islets and the inherent limitations of throughput and cost associated with the use of primary cells. Importantly, the strategy is easily adapted for human islet replication studies. This assay is well suited for investigating the mitogenic effect of substances on &#946;-cells and the molecular mechanisms that regulate &#946;-cell growth.

To assess &#946;-cell or &#945;-cell replication, a four-color assay protocol is required. First, objects are identified by DAPI staining (Channel 1, 386 nm). Next, &#946;-cells (event 1) are counted: objects that co-express PDX-1+ (channel 2, 650 nm) and peri-nuclear insulin (channel 3, 549 nm). Subsequently, replicating &#946;-cells (event 2) are counted: &#946;-cells (event 1) that co-express Ki-67 (channel 4, 485 nm) (Figure 3). The percentage of replicatin...

Watch this Scientific Journal Video about A High-content In Vitro Pancreatic Islet Î²-cell Replication Discovery Platform at JoVE.com

A High-content In Vitro Pancreatic Islet &amp;#946;-cell Replication Discovery Platform

Critical challenges for the diabetes research field are to understand the molecular mechanisms that regulate islet &#946;-cell replication and to develop methods for stimulating &#946;-cell regeneration. Herein a high-content screening method to identify and assess the &#946;-cell replication-promoting activity of small molecules is presented.

A High-content In Vitro Pancreatic Islet &#946;-cell Replication Discovery Platform

Loss of insulin-producing &#946;-cells is a central feature of diabetes. While a variety of potential replacement therapies are being explored, expansion ...

The overall goal of this high content beta cell replication screening platform, is to facilitate the investigation of the molecular pathways that restrict beta cell growth. This method can help answer important questions in the beta cell biology field. Such as one of the key signaling molecules and pathways that control beta cell regeneration.The main advantages of this technique are that it enables increasing the throughput cell lining to a specific assessment and the automated data analyst of a primary islet cell replication. The employment of this technique has the potential to extend toward the development of the regenerative therapy for diabetes. A disease with major health and economic cost to our society.Begin by using a pancreatic digestive solution loaded 10 milliliter syringe equipped with a 22 gauge needle to chemulate the common bile duct at or just distal to the junction of the cystic and common hepatic ducts. Supporting the common bile duct with a scalple handle, slowly inject 10 milliliters of the solution. After all of the collagenase has been administered, used curved forceps and scissors to separate the inflated pancreas from the descending colon, intestines, stomach, and spline.Then place up to two pancreata in a 50 milliliter tube on ice containing five milliliters of pancreatic digestion solution. When all of the pancreata have been collected, place the digestion tubes in a 37 degree Celsius water bath for 15 minutes with gentle swirling every three minutes. At the end of the digestion, vigorously shake the tubes vertically 10 times.And add 10 milliliters of cold wash buffers to the specimens. Vigorously shake the tubes five more times and place them on ice. Next fill the tubes to a final volume of 50 milliliters with cold wash buffer and invert the tubes five times.Then spin down the tissues and pour off the supernatants, taking care not to dislodge the pellets. Re-suspend the tissue slurry in 25 milliliters of wash buffer followed by gentle vortexing. Repeat the spinning and re-suspension steps two more times.The pour the tissue suspensions through a 30 mesh tissue sieve into a sterile 250 milliliter beaker. Rinse the digestion tubes with an additional 20 milliliters of wash buffer and pour the washes onto the mesh to remove the undigested pancreatic and fat tissues. Divide the filtered material between two new 50 milliliter tubes and pellet the tissue by centrifugation.Then decant the supernatant and invert the tubes to drain the excess buffer. To purify the islets, add 20 milliliters of cold density gradient to the pancreatic tissue pellets and gently pipet up and down five times to homogeneously re-suspend the contents. Next slowly overlay 10 milliliters of HBSS down the wall of each tube of gradient taking care to maintain a sharp liquid interface and separate the pancreatic cells by centrifugation.Use a 10 milliliter pipet to transfer the islet layer from the interface into new 50 milliliter conical tubes. Then wash the islets in 40 to 50 milliliters of wash buffer three times. Inverting their tubes to re-suspend the pellets between each centrifugation.After the final wash, bring the tubes into a tissue culture hood. Aspirate the supernatant. And re-suspend the pellets in six milliliters of islet medium.Sieve the islets from each tube in individual wells of six well tissue culture plate. And swirl the plate to collect the islets in the middles of the wells. Evaluate islet purity under the microscope.To further purify the islets, collect them using a one milliliter pipet and transfer to the adjacent well using six milliliters of islet medium. Repeat islet swirling, collection, transfer and microscopic evaluation until greater than 90 percent purity is achieved. Next, transfer the islets to a single 10 centimeter tissue culture dish containing 20 milliliters of islet medium.After all of the islets have been harvested, place the culture dish in a tissue culture incubator overnight. Then coat the wells of a 384 well plate with 40 microliters of 804G, conditioned medium per well and place the plate in the incubator overnight. The next day, use a cell scraper to gently detach the islets.Then transfer the islets into a 50 milliliter tube. Collect the islets by centrifugation. Then wash them with 20 milliliters of warm p, b, s.Centrifuge for one minute. Aspirate the supernatant. And re-suspend the pellet in zero point two, five percent Trypsin.Incubate the islets for 10 minutes at 37 degrees Celsius using a one milliliter pipet to aspirate and dispense the islets 10 times at five and 10 minutes. After the second triteration, count a 20 microliter sample of the trypsinized islet cells. If the tissues are fully digested, suspend the dissociative islet cells at a four point five times ten to the four cell per milliliter concentration in islet function medium.Then use a 12 well manifold aspirator to remove the 804G condition medium from the previously prepared 384 well plate. And sieve 70 microliters of islets per well into rows c to n in columns four to 21. Allow the islets to adhere in the tissue culture incubator for 48 hours.After two day, use the 12 well manifold aspirator to carefully remove the islet medium and use a 12 channel pipet to add 35 microliters of islet function medium to each well. Then transfer 35 microliters of the freshly prepared two, x compound solutions of interest to each well. And return the islets to the incubator for another 48 hours.After 48 hours, fix, stain, and analyze the compound treated islets cultures using an automated high content imaging platform. In a typical experiment, the replication rate of the DAPI, PD-1 and insulin positive beta cells is determined by the percentage of beta cells co-expressing Ki-67. Alpha cell replication is measured as the percentage of DAPI positive, PD negative, Glucagon positive, Ki-67 co-expressing cells.For example in this representative experiment, Dipryridamole was observed to promote the replication of beta but not alpha cells. This technique can be completed in seven days. Following this procedure compounds that in the beta cell replication can be studied further to reveal the mechanisms of action.This technique has enabled researches in the field of beta cell biology to identify new signaling factors and pathways that regulate beta cell growth. After watching this video, you should have a good understanding of how to test the ability of small molecules to selective stimulate beta cell regeneration.

a-high-content-vitro-pancreatic-islet-cell-replication-discovery

Research

JoVE Journal

Medicine

A Method for Murine Islet Isolation and Subcapsular Kidney Transplantation

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize their blood glucose levels, islet transplantation has been proposed to be a potential treatment for type 1 diabetes 1,2. More recently, advances in human islet transplantation have further strengthened this view 1,3. However, two major limitations prevent islet transplantation from being a widespread clinical reality: (a) the requirement for large numbers of islets per patient, which severely reduces the number of potential recipients, and (b) the need for heavy immunosuppression, which significantly affects the pediatric population of patients due to their vulnerability to long-term immunosuppression. Strategies that can overcome these limitations have the potential to enhance the therapeutic utility of islet transplantation.
Islet transplantation under the mouse kidney capsule is a widely accepted model to investigate various strategies to improve islet transplantation. This experiment requires the isolation of high quality islets and implantation of islets to the diabetic recipients. Both procedures require surgical steps that can be better demonstrated by video than by text. Here, we document the detailed steps for these procedures by both video and written protocol. We also briefly discuss different transplantation models: syngeneic, allogeneic, syngeneic autoimmune, and allogeneic autoimmune.

Transplantation of isolated islets has been proposed to be a potential treatment for type 1 diabetes. Here we describe a method to isolate islets from mouse pancreata and transplant them to the subcapsular space of the kidney.

Since the early pioneering work of Ballinger and Reckard demonstrating that transplantation of islets of Langerhans into diabetic rodents could normalize ...

High Content Screening in Neurodegenerative Diseases

The functional annotation of genomes, construction of molecular networks and novel drug target identification, are important challenges that need to be addressed as a matter of great urgency1-4. Multiple complementary 'omics' approaches have provided clues as to the genetic risk factors and pathogenic mechanisms underlying numerous neurodegenerative diseases, but most findings still require functional validation5. For example, a recent genome wide association study for Parkinson's Disease (PD), identified many new loci as risk factors for the disease, but the underlying causative variant(s) or pathogenic mechanism is not known6, 7. As each associated region can contain several genes, the functional evaluation of each of the genes on phenotypes associated with the disease, using traditional cell biology techniques would take too long. 
	There is also a need to understand the molecular networks that link genetic mutations to the phenotypes they cause. It is expected that disease phenotypes are the result of multiple interactions that have been disrupted. Reconstruction of these networks using traditional molecular methods would be time consuming. Moreover, network predictions from independent studies of individual components, the reductionism approach, will probably underestimate the network complexity8. This underestimation could, in part, explain the low success rate of drug approval due to undesirable or toxic side effects. Gaining a network perspective of disease related pathways using HT/HC cellular screening approaches, and identifying key nodes within these pathways, could lead to the identification of targets that are more suited for therapeutic intervention.
	High-throughput screening (HTS) is an ideal methodology to address these issues9-12. but traditional methods were one dimensional whole-well cell assays, that used simplistic readouts for complex biological processes. They were unable to simultaneously quantify the many phenotypes observed in neurodegenerative diseases such as axonal transport deficits or alterations in morphology properties13, 14. This approach could not be used to investigate the dynamic nature of cellular processes or pathogenic events that occur in a subset of cells. To quantify such features one has to move to multi-dimensional phenotypes termed high-content screening (HCS)4, 15-17. HCS is the cell-based quantification of several processes simultaneously, which provides a more detailed representation of the cellular response to various perturbations compared to HTS. 
	HCS has many advantages over HTS18, 19, but conducting a high-throughput (HT)-high-content (HC) screen in neuronal models is problematic due to high cost, environmental variation and human error. In order to detect cellular responses on a 'phenomics' scale using HC imaging one has to reduce variation and error, while increasing sensitivity and reproducibility. 
	Herein we describe a method to accurately and reliably conduct shRNA screens using automated cell culturing20 and HC imaging in neuronal cellular models. We describe how we have used this methodology to identify modulators for one particular protein, DJ1, which when mutated causes autosomal recessive parkinsonism21. 
	Combining the versatility of HC imaging with HT methods, it is possible to accurately quantify a plethora of phenotypes. This could subsequently be utilized to advance our understanding of the genome, the pathways involved in disease pathogenesis as well as identify potential therapeutic targets.

We describe a methodology combining automated cell culturing with high-content imaging to visualize and quantify multiple cellular processes and structures, in a high-throughput manner. Such methods can aid in the further functional annotation of genomes as well as identify disease gene networks and potential drug targets.

The functional annotation of genomes, construction of molecular networks and novel drug target identification, are important challenges that need to be ...

The Use of Cystometry in Small Rodents: A Study of Bladder Chemosensation

The lower urinary tract (LUT) functions as a dynamic reservoir that is able to store urine and to efficiently expel it at a convenient time. While storing urine, however, the bladder is exposed for prolonged periods to waste products. By acting as a tight barrier, the epithelial lining of the LUT, the urothelium, avoids re-absorption of harmful substances. Moreover, noxious chemicals stimulate the bladder's nociceptive innervation and initiate voiding contractions that expel the bladder's contents. Interestingly, the bladder's sensitivity to noxious chemicals has been used successfully in clinical practice, by intravesically infusing the TRPV1 agonist capsaicin to treat neurogenic bladder overactivity1. This underscores the advantage of viewing the bladder as a chemosensory organ and prompts for further clinical research. However, ethical issues severely limit the possibilities to perform, in human subjects, the invasive measurements that are necessary to unravel the molecular bases of LUT clinical pharmacology. A way to overcome this limitation is the use of several animal models2. Here we describe the implementation of cystometry in mice and rats, a technique that allows measuring the intravesical pressure in conditions of controlled bladder perfusion.
	After laparotomy, a catheter is implanted in the bladder dome and tunneled subcutaneously to the interscapular region. Then the bladder can be filled at a controlled rate, while the urethra is left free for micturition. During the repetitive cycles of filling and voiding, intravesical pressure can be measured via the implanted catheter. As such, the pressure changes can be quantified and analyzed. Moreover, simultaneous measurement of the voided volume allows distinguishing voiding contractions from non-voiding contractions3.
	Importantly, due to the differences in micturition control between rodents and humans, cystometric measurements in these animals have only limited translational value4. Nevertheless, they are quite instrumental in the study of bladder pathophysiology and pharmacology in experimental pre-clinical settings. Recent research using this technique has revealed the key role of novel molecular players in the mechano- and chemo-sensory properties of the bladder.

Cystometry is an efficient technique to measure bladder function of small animals in vivo. The bladder is continuously infused at rates controlled through an intravesical catheter, whereas the urethra is left free for micturition. This allows for repetitive filling and emptying of the bladder, while intravesical pressure and voided volume are recorded.

	The lower urinary tract (LUT) functions as a  dynamic reservoir that is able to store urine and to efficiently expel it at a  convenient time. While ...

Simulating Pancreatic Neuroplasticity: In Vitro Dual-neuron Plasticity Assay

Neuroplasticity is an inherent feature of the enteric nervous system and gastrointestinal (GI) innervation under pathological conditions. However, the pathophysiological role of neuroplasticity in GI disorders remains unknown. Novel experimental models which allow simulation and modulation of GI neuroplasticity may enable enhanced appreciation of the contribution of neuroplasticity in particular GI diseases such as pancreatic cancer (PCa) and chronic pancreatitis (CP). Here, we present a protocol for simulation of pancreatic neuroplasticity under in vitro conditions using newborn rat dorsal root ganglia (DRG) and myenteric plexus (MP) neurons. This dual-neuron approach not only permits monitoring of both organ-intrinsic and -extrinsic neuroplasticity, but also represents a valuable tool to assess neuronal and glial morphology and electrophysiology. Moreover, it allows functional modulation of supplied microenvironmental contents for studying their impact on neuroplasticity. Once established, the present neuroplasticity assay bears the potential of being applicable to the study of neuroplasticity in any GI organ.

Simulating Pancreatic Neuroplasticity: In Vitro Dual-neuron Plasticity Assay

Neuronal plasticity is an increasingly recognized, but insufficiently understood feature of the gastrointestinal (GI) tract. Here, in the example of human pancreatic disorders, we present an in vitro neuroplasticity assay for the study of neuronal plasticity in the GI tract at both morphological and functional level.

Neuroplasticity is an inherent feature of the enteric nervous system and gastrointestinal (GI) innervation under pathological conditions. However, the ...

Leprdb Mouse Model of Type 2 Diabetes: Pancreatic Islet Isolation and Live-cell 2-Photon Imaging Of Intact Islets

Type 2 diabetes is a chronic disease affecting 382 million people in 2013, and is expected to rise to 592 million by 2035 1. During the past 2 decades, the role of beta-cell dysfunction in type 2 diabetes has been clearly established 2. Research progress has required methods for the isolation of pancreatic islets. The protocol of the islet isolation presented here shares many common steps with protocols from other groups, with some modifications to improve the yield and quality of isolated islets from both the wild type and diabetic Leprdb (db/db) mice. A live-cell 2-photon imaging method is then presented that can be used to investigate the control of insulin secretion within islets.

Leprdb Mouse Model of Type 2 Diabetes: Pancreatic Islet Isolation and Live-cell 2-Photon Imaging Of Intact Islets

We present here a protocol for the isolation of islets from the mouse model of type 2 diabetes, Leprdb and details of a live-cell assay for measurement of insulin secretion from intact islets that utilizes 2 photon microscopy.

Type 2 diabetes is a chronic disease affecting 382 million people in 2013, and is expected to rise to 592 million by 2035 1. During the past 2 decades, ...

Studying Pancreatic Cancer Stem Cell Characteristics for Developing New Treatment Strategies

Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor initiation, metastasis and resistance to radio- and chemotherapy. Here we describe a specific methodology for culturing primary human pancreatic CSCs as tumor spheres in anchorage-independent conditions. Cells are grown in serum-free, non-adherent conditions in order to enrich for CSCs while their more differentiated progenies do not survive and proliferate during the initial phase following seeding of single cells. This assay can be used to estimate the percentage of CSCs present in a population of tumor cells. Both size (which can range from 35 to 250 micrometers) and number of tumor spheres formed represents CSC activity harbored in either bulk populations of cultured cancer cells or freshly harvested and digested tumors 1,2. Using this assay, we recently found that metformin selectively ablates pancreatic CSCs; a finding that was subsequently further corroborated by demonstrating diminished expression of pluripotency-associated genes/surface markers and reduced in vivo tumorigenicity of metformin-treated cells. As the final step for preclinical development we treated mice bearing established tumors with metformin and found significantly prolonged survival. Clinical studies testing the use of metformin in patients with PDAC are currently underway (e.g., NCT01210911, NCT01167738, and NCT01488552). Mechanistically, we found that metformin induces a fatal energy crisis in CSCs by enhancing reactive oxygen species (ROS) production and reducing mitochondrial transmembrane potential. In contrast, non-CSCs were not eliminated by metformin treatment, but rather underwent reversible cell cycle arrest. Therefore, our study serves as a successful example for the potential of in vitro sphere formation as a screening tool to identify compounds that potentially target CSCs, but this technique will require further in vitro and in vivo validation to eliminate false discoveries.

Pancreatic cancer stem cells (CSCs) can be expanded in vitro using the anchorage-independent sphere culture technique, which represents a powerful tool to study CSC biology and can serve as the first step to develop novel CSC-targeting therapies. Here the methodology for expanding, analyzing and targeting of pancreatic CSCs is provided.

Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor ...

Laser Doppler: A Tool for Measuring Pancreatic Islet Microvascular Vasomotion In Vivo

As a functional status of microcirculation, microvascular vasomotion is important for the delivery of oxygen and nutrients and the removal of carbon dioxide and waste products. The impairment of microvascular vasomotion might be a crucial step in the development of microcirculation-related diseases. In addition, the highly vascularized pancreatic islet is adapted to support endocrine function. In this respect, it seems possible to infer that the functional status of pancreatic islet microvascular vasomotion might affect pancreatic islet function. Analyzing the pathological changes of the functional status of pancreatic islet microvascular vasomotion may be a feasible strategy to determine contributions that pancreatic islet microcirculation makes to related diseases, such as diabetes mellitus, pancreatitis, etc. Therefore, this protocol describes using a laser Doppler blood flow monitor to determine the functional status of pancreatic islet microvascular vasomotion, and to establish parameters (including average blood perfusion, amplitude, frequency, and relative velocity of pancreatic islet microvascular vasomotion) for evaluation of the microcirculatory functional status. In a streptozotocin-induced diabetic mouse model, we observed an impaired functional status of pancreatic islet microvascular vasomotion. In conclusion, this approach for assessing pancreatic islet microvascular vasomotion in vivo may reveal mechanisms relating to pancreatic islet diseases.

Laser Doppler: A Tool for Measuring Pancreatic Islet Microvascular Vasomotion In Vivo

Pancreatic islet microvascular vasomotion regulates islet blood distribution and maintains the physiological function of islet &#946; cells. This protocol describes using a laser Doppler monitor to determine the functional status of pancreatic islet microvascular vasomotion in vivo and to assess the contributions of pancreatic islet microcirculation to pancreatic-related diseases.

As a functional status of microcirculation, microvascular vasomotion is important for the delivery of oxygen and nutrients and the removal of carbon ...

Application of End-to-end Anastomosis in Robotic Central Pancreatectomy

Central pancreatectomy is carried out for the treatment of benign or low-malignant potential tumors located in the pancreatic neck or proximal part of pancreatic body. With technological development, the robotic surgical system has shown its advantage in minimally invasive surgery and been increasingly applied in central pancreatectomy. However, reconstruction of the continuity of pancreas with end-to-end anastomosis after robotic central pancreatectomy has not been applied. In this study, we report surgical techniques for robotic central pancreatectomy with end-to-end anastomosis. The pancreas is reconstructed by duct-to-duct anastomosis of the pancreatic duct with a pancreatic stent inserted in the two stumps of pancreatic duct, and by end-to-end anastomosis of the pancreatic parenchyma. Compared with traditional central pancreatectomy with pancreaticoenteric anastomosis, this approach decreases the operative injury to the patient, and also conserves the integrity and continuity of the digestive duct and pancreatic duct. The robotic surgical system integrated with multiple instruments with flexible and precise movement is particularly suitable for the dissection and reconstruction of the pancreatic duct. We found that robotic central pancreatectomy with end-to-end anastomosis is safe and feasible, and we need more experience to evaluate its best indications and long-term outcomes.

The robotic central pancreatectomy with end-to-end anastomosis is feasible and safe for tumor in the pancreatic neck and proximal portion of pancreatic body. The operative techniques of this operation are presented.

Central pancreatectomy is carried out for the treatment of benign or low-malignant potential tumors located in the pancreatic neck or proximal part of ...

Hydra, a Computer-Based Platform for Aiding Clinicians in Cardiovascular Analysis and Diagnosis

Cardiovascular diseases (CVDs) are the leading cause of death throughout the world. The total risk of developing CVD is determined by the combined effect of different cardiovascular risk factors (e.g., diabetes, raised blood pressure, unhealthy diet, tobacco use, stress, etc.) that commonly coexist and act multiplicatively. Most CVDs can be prevented by an early identification of the highest risk factors and an appropriate treatment. The stratification of cardiovascular risk factors involves a wide range of parameters and tests that specialists use in their clinical practice. In addition to cardiovascular (CV) risk stratification, ambulatory blood pressure monitoring (ABPM) also provides relevant information for diagnostic and treatment purposes. This work presents a list of protocols based on the Hydra platform, a web-based system for clinical decision support which incorporates a set of functionalities and services that are required for complete cardiovascular analysis, risk assessment, early diagnosis, treatment and monitoring of patients over time. The program includes tools for inputting and managing comprehensive patient data, organized into different checkups to track the evolution over time. It also has a risk stratification tool to compute a CV risk factor based upon several risk stratification tables of reference. Additionally, the program includes a tool that incorporates ABPM analysis and allows the extraction of valuable information by monitoring blood pressure over a specific period of time. Finally, the reporting service summarizes the most relevant information in a set of reports that aid clinicians in their clinical decision-making process.

This article presents a protocol based on Hydra &#8212; a web-based system for clinical decision support that integrates a full and detailed set of functionalities and services required by physicians for complete cardiovascular analysis, risk assessment, early diagnosis, treatment, and monitoring over time.

Cardiovascular diseases (CVDs) are the leading cause of death throughout the world. The total risk of developing CVD is determined by the combined effect ...

Visualization of Endogenous Mitophagy Complexes In Situ in Human Pancreatic Beta Cells Utilizing Proximity Ligation Assay

Mitophagy is an essential mitochondrial quality control pathway, which is crucial for pancreatic islet beta cell bioenergetics to fuel glucose-stimulated insulin release. Assessment of mitophagy is challenging and often requires genetic reporters or multiple complementary techniques not easily utilized in tissue samples, such as primary human pancreatic islets. Here we demonstrate a robust approach to visualize and quantify formation of key endogenous mitophagy complexes in primary human pancreatic islets. Utilizing the sensitive proximity ligation assay technique to detect interaction of the mitophagy regulators NRDP1 and USP8, we are able to specifically quantify formation of essential mitophagy complexes in situ. By coupling this approach to counterstaining for the transcription factor PDX1, we can quantify mitophagy complexes, and the factors that can impair mitophagy, specifically within beta cells. The methodology we describe overcomes the need for large quantities of cellular extracts required for other protein-protein interaction studies, such as immunoprecipitation (IP) or mass spectrometry, and is ideal for precious human islet&#160;samples generally not available in sufficient quantities for these approaches. Further, this methodology obviates the need for flow sorting techniques to purify beta cells from a heterogeneous islet population for downstream protein applications. Thus, we describe a valuable protocol for visualization of mitophagy highly compatible for use in heterogeneous and limited cell populations.

This protocol outlines a method for quantitative analysis of mitophagy protein complex formation specifically in beta cells from primary human islet samples. This technique thus allows analysis of mitophagy from limited biological material, which are crucial in precious human pancreatic beta cell samples.

Mitophagy is an essential mitochondrial quality control pathway, which is crucial for pancreatic islet beta cell bioenergetics to fuel glucose-stimulated ...