This work was funded by NIH grants R01 DK123292, T32 DK108736, UC4 DK104194, UG3 DK122638, and P01 AI042288. This research was performed with the support of the Network for Pancreatic Organ donors with Diabetes (nPOD; RRID:SCR_014641), a collaborative type 1 diabetes research project sponsored by JDRF (nPOD: 5-SRA-2018-557-Q-R), and The Leona M. &#38; Harry B. Helmsley Charitable Trust (Grant #2018PG-T1D053). The content and views expressed are the responsibility of the authors and do not necessarily reflect the official view of nPOD. Organ Procurement Organizations (OPO) partnering with nPOD to provide research resources are listed at http://www.jdrfnpod.org/for-partners/npod-partners/. Thank you to Dr. Kevin Otto, University of Florida, for providing the vibratome used to generate mouse slices.&#160;

<ol>
	<li>Uc, A., Fishman, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pancreatic+disorders.">Pancreatic disorders.</a> Pediatric Clinics of North America. 64 (3), 685-706 (2017).</li><li>Bluestone, J. A., Herold, K., Eisenbarth, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics,+pathogenesis+and+clinical+interventions+in+type+1+diabetes.">Genetics, pathogenesis and clinical interventions in type 1 diabetes.</a> Nature. 464 (7293), 1293-1300 (2010).</li><li>Taylor, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Type+2+diabetes:+etiology+and+reversibility.">Type 2 diabetes: etiology and reversibility.</a> Diabetes Care. 36 (4), 1047-1055 (2013).</li><li>Meier, R. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Islet+of+Langerhans+isolation+from+pediatric+and+juvenile+donor+pancreases.">Islet of Langerhans isolation from pediatric and juvenile donor pancreases.</a> Transplant International. 27 (9), 949-955 (2014).</li><li>Marciniak, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+pancreas+tissue+slices+for+in+situ+studies+of+islet+of+Langerhans+and+acinar+cell+biology.">Using pancreas tissue slices for in situ studies of islet of Langerhans and acinar cell biology.</a> Nature Protocols. 9 (12), 2809-2822 (2014).</li><li>Panzer, J. K., Cohrs, C. M., Speier, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+pancreas+tissue+slices+for+the+study+of+islet+physiology.">Using pancreas tissue slices for the study of islet physiology.</a> Methods in Molecular Biology. 2128, 301-312 (2020).</li><li>Speier, S., Rupnik, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+approach+to+in+situ+characterization+of+pancreatic+beta-cells.">A novel approach to in situ characterization of pancreatic beta-cells.</a> Pflugers Archive. 446 (5), 553-558 (2003).</li><li>Panzer, J. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pancreas+tissue+slices+from+organ+donors+enable+in+situ+analysis+of+type+1+diabetes+pathogenesis.">Pancreas tissue slices from organ donors enable in situ analysis of type 1 diabetes pathogenesis.</a> JCI Insight. 5 (8), 134525 (2020).</li><li>Dolai, 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=Pancreatitis-induced+depletion+of+syntaxin+2+promotes+autophagy+and+increases+basolateral+exocytosis.">Pancreatitis-induced depletion of syntaxin 2 promotes autophagy and increases basolateral exocytosis.</a> Gastroenterology. 154 (6), 1805-1821 (2018).</li><li>Dolai, 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=Pancreas-specific+SNAP23+depletion+prevents+pancreatitis+by+attenuating+pathological+basolateral+exocytosis+and+formation+of+trypsin-activating+autolysosomes.">Pancreas-specific SNAP23 depletion prevents pancreatitis by attenuating pathological basolateral exocytosis and formation of trypsin-activating autolysosomes.</a> Autophagy. , 1-14 (2020).</li><li>Qadir, M. M. F., 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=Long-term+culture+of+human+pancreatic+slices+as+a+model+to+study+real-time+islet+regeneration.">Long-term culture of human pancreatic slices as a model to study real-time islet regeneration.</a> Nature Communications. 11 (1), 3265 (2020).</li><li>Cohrs, C. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dysfunction+of+persisting+&#946;+cells+is+a+key+feature+of+early+type+2+diabetes+pathogenesis.">Dysfunction of persisting &#946; cells is a key feature of early type 2 diabetes pathogenesis.</a> Cell Reports. 31 (1), 107469 (2020).</li><li>Liang, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+vivo+human+pancreatic+slice+preparations+offer+a+valuable+model+for+studying+pancreatic+exocrine+biology.">Ex vivo human pancreatic slice preparations offer a valuable model for studying pancreatic exocrine biology.</a> Journal of Biological Chemistry. 292 (14), 5957-5969 (2017).</li><li>Shultz, L. D., Ishikawa, F., Greiner, D. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Humanized+mice+in+translational+biomedical+research.">Humanized mice in translational biomedical research.</a> Nat Reviews. Immunology. 7 (2), 118-130 (2007).</li><li>Lamont, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Compensatory+mechanisms+allow+undersized+anchor-deficient+class+I+MHC+ligands+to+mediate+pathogenic+autoreactive+T+cell+responses.">Compensatory mechanisms allow undersized anchor-deficient class I MHC ligands to mediate pathogenic autoreactive T cell responses.</a> Journal of Immunology. 193 (5), 2135-2146 (2014).</li><li>Fish, R., Danneman, P. J., Brown, M., Karas, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Anesthesia and analgesia in laboratory animals. , (2011).</li><li>Clark, S. A., Borland, K. M., Sherman, S. D., Rusack, T. C., Chick, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Staining+and+in+vitro+toxicity+of+dithizone+with+canine,+porcine,+and+bovine+islets.">Staining and in vitro toxicity of dithizone with canine, porcine, and bovine islets.</a> Cell Transplantation. 3 (4), 299-306 (1994).</li><li>Schindelin, J., 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=Fiji:+an+open-source+platform+for+biological-image+analysis.">Fiji: an open-source platform for biological-image analysis.</a> Nature Methods. 9 (7), 676-682 (2012).</li><li>Monette, R., Small, D. L., Mealing, G., Morley, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+fluorescence+confocal+assay+to+assess+neuronal+viability+in+brain+slices.">A fluorescence confocal assay to assess neuronal viability in brain slices.</a> Brain Research Protocols. 2 (2), 99-108 (1998).</li><li>G&#225;l, E., 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=A+novel+in+situ+approach+to+studying+pancreatic+ducts+in+mice.">A novel in situ approach to studying pancreatic ducts in mice.</a> Frontiers in Physiology. 10, 938 (2019).</li><li>Sto&#382;er, A., Dolen&#353;ek, J., Rupnik, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucose-stimulated+calcium+dynamics+in+islets+of+Langerhans+in+acute+mouse+pancreas+tissue+slices.">Glucose-stimulated calcium dynamics in islets of Langerhans in acute mouse pancreas tissue slices.</a> PloS One. 8 (1), 54638 (2013).</li><li>Sto&#382;er, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+connectivity+in+islets+of+Langerhans+from+mouse+pancreas+tissue+slices.">Functional connectivity in islets of Langerhans from mouse pancreas tissue slices.</a> PLoS Computational Biology. 9 (2), 1002923 (2013).</li><li>Fr&#252;h, E., Elgert, C., Eggert, F., Scherneck, S., Rustenbeck, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucagonotropic+and+glucagonostatic+effects+of+KATP+channel+closure+and+potassium+depolarization.">Glucagonotropic and glucagonostatic effects of KATP channel closure and potassium depolarization.</a> Endocrinology. 162 (1), 136 (2021).</li><li>Satin, L. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+mechanisms+for+sulfonylurea+control+of+insulin+secretion.">New mechanisms for sulfonylurea control of insulin secretion.</a> Endocrine. 4 (3), 191-198 (1996).</li><li>Ren, J., 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=Slow+oscillations+of+KATP+conductance+in+mouse+pancreatic+islets+provide+support+for+electrical+bursting+driven+by+metabolic+oscillations.">Slow oscillations of KATP conductance in mouse pancreatic islets provide support for electrical bursting driven by metabolic oscillations.</a> American Journal of Physiology-Endocrinology and Metabolism. 305 (7), 805-817 (2013).</li><li>Marciniak, A., Selck, C., Friedrich, B., Speier, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mouse+pancreas+tissue+slice+culture+facilitates+long-term+studies+of+exocrine+and+endocrine+cell+physiology+in+situ.">Mouse pancreas tissue slice culture facilitates long-term studies of exocrine and endocrine cell physiology in situ.</a> PLoS One. 8 (11), 78706 (2013).</li><li>Dzhagalov, I. L., Melichar, H. J., Ross, J. O., Herzmark, P., Robey, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-photon+imaging+of+the+immune+system.">Two-photon imaging of the immune system.</a> Current Protocols in Cytometry. , (2012).</li></ol>

The authors declare no competing interests.

The objective of this protocol is to explicate the generation of pancreas slices and the procedures needed to employ the slices in functional and immunological studies. There are many benefits to using live pancreatic slices. However, there are several critical steps that are essential for the tissue to remain viable and useful during the described experiment protocols. It is imperative to work quickly. The length of time between injecting the pancreas and generating the slices on the vibratome should be minimized to mai...

Involvement of the pancreas is pathognomonic to diseases such as pancreatitis, T1D, and T2D1,2,3. The study of function in isolated islets usually involves removal of the islets from their surrounding environment4. The live pancreatic tissue slice method was developed to allow for the study of pancreatic tissue while maintaining intact islet microenvironments and avoiding the use of stressful islet isolation procedures5,6,7. Pancreatic tissue slices from human donor tissue have been successfully used to study T1D and have demonstrated processes of beta cell loss and dysfunction in addition to immune cell infiltration8,9,10,11,12,13. The live pancreatic tissue slice method can be applied to both mouse and human pancreatic tissue5,6,8. Human pancreatic tissue slices from organ donor tissues are obtained through a collaboration with the Network for Pancreatic Organ Donors with Diabetes (nPOD). Mouse slices can be generated from a variety of different mouse strains.
This protocol will focus on non-obese diabetic-recombination activating gene-1-null (NOD.Rag1-/-) and T cell receptor transgenic (AI4) (NOD.Rag1-/-.AI4&#945;/&#946;) mouse strains. NOD.Rag1-/- mice are unable to develop T and B cells due to a disruption in the recombination-activating gene 1 (Rag1)14. NOD.Rag1-/-.AI4&#945;/&#946; mice are used as a model for accelerated type 1 diabetes because they produce a single T cell clone that targets an epitope of insulin, resulting in consistent islet infiltration and rapid disease development15. The protocol featured here describes procedures for functional and immunological studies using live human and mouse pancreatic slices through the application of confocal microscopy approaches. The techniques described herein include viability assessments, islet identification and location, cytosolic Ca2+ recordings, as well as staining and identification of immune cell populations.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>#3 Style Scalpel Handle</td>
			<td>Fisherbrand</td>
			<td>12-000-163</td>
			<td></td>
		</tr>
		<tr>
			<td>1 M HEPES</td>
			<td>Fisher Scientific</td>
			<td>BP299-100</td>
			<td>HEPES Buffer, 1M Solution</td>
		</tr>
		<tr>
			<td>10 cm Untreated Culture Dish</td>
			<td>Corning</td>
			<td>430591</td>
			<td></td>
		</tr>
		<tr>
			<td>10 mL Luer-Lok Syringe</td>
			<td>BD</td>
			<td>301029</td>
			<td>BD Syringe with Luer-Lok Tips</td>
		</tr>
		<tr>
			<td>27 G Needle</td>
			<td>BD</td>
			<td>BD 305109</td>
			<td>BD General Use and PrecisionGlide Hypodermic Needles</td>
		</tr>
		<tr>
			<td>35 mm coverglass-bottom Petri dish</td>
			<td>Ibidi</td>
			<td>81156</td>
			<td>&#181;-Dish 35 mm, high</td>
		</tr>
		<tr>
			<td>50 mL syringe</td>
			<td>BD</td>
			<td>309653</td>
			<td></td>
		</tr>
		<tr>
			<td>8-well chambered coverglass</td>
			<td>Ibidi</td>
			<td>80826</td>
			<td>&#181;-Slide 8 Well</td>
		</tr>
		<tr>
			<td>APC anti-mouse CD8a antibody</td>
			<td>Biolegend</td>
			<td>100712</td>
			<td></td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>Fisher Scientific</td>
			<td>199898</td>
			<td></td>
		</tr>
		<tr>
			<td>Calcium chloride</td>
			<td>Sigma</td>
			<td>C5670</td>
			<td>CaCl2</td>
		</tr>
		<tr>
			<td>Calcium chloride dihydrate</td>
			<td>Sigma</td>
			<td>C7902</td>
			<td>CaCl2 (dihydrate)</td>
		</tr>
		<tr>
			<td>Compact Digital Rocker</td>
			<td>Thermo Fisher Scientific</td>
			<td>88880020</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal laser-scanning microscope</td>
			<td>Leica</td>
			<td>SP8</td>
			<td>Pinhole&#8201;= 1.5-2 airy units; acquired with 10x/0.40 numerical aperture HC PL APO CS2 dry and 20x/0.75 numerical aperture HC PL APO CS2 dry objectives at 512&#8201;&#215;&#8201;512 pixel resolution</td>
		</tr>
		<tr>
			<td>D-(+)-Glucose</td>
			<td>Sigma</td>
			<td>G7021</td>
			<td>C6H12O6</td>
		</tr>
		<tr>
			<td>ddiH2O</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dithizone</td>
			<td>Sigma-Aldrich</td>
			<td>D5130-10G</td>
			<td></td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Invitrogen</td>
			<td>D12345</td>
			<td>Dimethyl sulfoxide</td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Decon Laboratories</td>
			<td>2805</td>
			<td></td>
		</tr>
		<tr>
			<td>Falcon 35 mm tissue culture dish</td>
			<td>Corning</td>
			<td>353001</td>
			<td>Falcon Easy-Grip Tissue Culture Dishes</td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Gibco</td>
			<td>10082147</td>
			<td></td>
		</tr>
		<tr>
			<td>Feather No. 10 Surgical Blade</td>
			<td>Electron Microscopy Sciences</td>
			<td>7204410</td>
			<td></td>
		</tr>
		<tr>
			<td>fluo-4-AM</td>
			<td>Invitrogen</td>
			<td>F14201</td>
			<td>cell-permeable Ca2+ indicator</td>
		</tr>
		<tr>
			<td>Gel Control Super Glue</td>
			<td>Loctite</td>
			<td>45198</td>
			<td></td>
		</tr>
		<tr>
			<td>Graefe Forceps</td>
			<td>Fine Science Tools</td>
			<td>11049-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Hardened Fine Scissors</td>
			<td>Fine Science Tools</td>
			<td>14090-09</td>
			<td></td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>Gibco</td>
			<td>14025092</td>
			<td>Hanks Balanced Salt Solution</td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma</td>
			<td>H4034</td>
			<td>C8H18N2O4S</td>
		</tr>
		<tr>
			<td>Ice bucket</td>
			<td>Fisherbrand</td>
			<td>03-395-150</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Patterson Veterinary</td>
			<td>NDC 14043-704-05</td>
			<td></td>
		</tr>
		<tr>
			<td>Johns Hopkins Bulldog Clamp</td>
			<td>Roboz Surgical Store</td>
			<td>RS-7440</td>
			<td>&#160;Straight; 500-900 Grams Pressure; 1.5&#34; Length</td>
		</tr>
		<tr>
			<td>Kimwipes</td>
			<td>Kimberly-Clark Professional</td>
			<td>34705</td>
			<td>Kimtech Science&#8482; Kimwipes&#8482; Delicate Task Wipers, 2-Ply</td>
		</tr>
		<tr>
			<td>LIVE/DEAD Viability/Cytotoxicity Kit</td>
			<td>Invitrogen</td>
			<td>L3224</td>
			<td>This kit contains the calcein-AM live cell dye.</td>
		</tr>
		<tr>
			<td>Low glucose DMEM</td>
			<td>Corning</td>
			<td>10-014-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium chloride hexahydrate</td>
			<td>Sigma</td>
			<td>M9272</td>
			<td>MgCl2 (hexahydrate)</td>
		</tr>
		<tr>
			<td>Magnesium sulfate heptahydrate</td>
			<td>Sigma</td>
			<td>M2773</td>
			<td>MgSO4 (heptahydrate)</td>
		</tr>
		<tr>
			<td>Magnetic Heated Platform</td>
			<td>Warner Instruments</td>
			<td>PM-1</td>
			<td>Platform for imaging chamber for dynamic stimulation recordings</td>
		</tr>
		<tr>
			<td>Microwave</td>
			<td>GE</td>
			<td>JES1460DSWW</td>
			<td></td>
		</tr>
		<tr>
			<td>Nalgene Syringe Filter</td>
			<td>Thermo Fisher Scientific</td>
			<td>726-2520</td>
			<td></td>
		</tr>
		<tr>
			<td>No.4 Paintbrush</td>
			<td>Michaels</td>
			<td>10269140</td>
			<td></td>
		</tr>
		<tr>
			<td>Open Diamond Bath Imaging Chamber</td>
			<td>Warner Instruments</td>
			<td>RC-26</td>
			<td>Imaging chamber for dynamic stimulation recordings</td>
		</tr>
		<tr>
			<td>Oregon Green 488 BAPTA-1-AM</td>
			<td>Invitrogen</td>
			<td>O6807</td>
			<td>cell-permeable Ca2+ indicator</td>
		</tr>
		<tr>
			<td>Overnight imaging chamber</td>
			<td>Okolab</td>
			<td>H201-LG</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>Thermo Fisher Scientific</td>
			<td>20012050</td>
			<td>To make agarose for slice generation</td>
		</tr>
		<tr>
			<td>PE-labeled insulin tetramer</td>
			<td>Emory Tetramer Research Core</td>
			<td>sequence YAIENYLEL</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin Streptomycin</td>
			<td>Gibco</td>
			<td>15140122</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Sigma</td>
			<td>P5405</td>
			<td>KCl</td>
		</tr>
		<tr>
			<td>Potassium phosphate monobasic</td>
			<td>Sigma</td>
			<td>P5655</td>
			<td>KH2PO4</td>
		</tr>
		<tr>
			<td>Razor Blades</td>
			<td>Electron Microscopy Sciences</td>
			<td>71998</td>
			<td>For Vibratome; Double Edge Stainless Steel, uncoated</td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Gibco</td>
			<td>11875093</td>
			<td></td>
		</tr>
		<tr>
			<td>SeaPlaque low melting-point agarose</td>
			<td>Lonza</td>
			<td>50101</td>
			<td>To make agarose for slice generation</td>
		</tr>
		<tr>
			<td>Slice anchor</td>
			<td>Warner Instruments</td>
			<td>64-1421</td>
			<td></td>
		</tr>
		<tr>
			<td>Slice anchor (dynamic imaging)</td>
			<td>Warner Instruments</td>
			<td>640253</td>
			<td>Slice anchor for dynamic imaging chamber</td>
		</tr>
		<tr>
			<td>Sodium bicarbonate</td>
			<td>Sigma</td>
			<td>S5761</td>
			<td>NaHCO3</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Sigma</td>
			<td>S5886</td>
			<td>NaCl</td>
		</tr>
		<tr>
			<td>Sodium phosphate monohydrate</td>
			<td>Sigma</td>
			<td>S9638</td>
			<td>NaH2PO4 (monohydrate)</td>
		</tr>
		<tr>
			<td>Soybean Trypsin Inhibitor</td>
			<td>Sigma</td>
			<td>T6522-1G</td>
			<td>Trypsin inhibitor from Glycine max (soybean)</td>
		</tr>
		<tr>
			<td>Stage Adapter</td>
			<td>Warner Instruments</td>
			<td>SA-20MW-AL</td>
			<td>To fit imaging chamber for dynamic stimulation recordings on the microscope stage</td>
		</tr>
		<tr>
			<td>Stage-top incubator</td>
			<td>Okolab</td>
			<td>H201</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereoscope</td>
			<td>Leica</td>
			<td>IC90 E MSV266</td>
			<td></td>
		</tr>
		<tr>
			<td>SYTOX Blue Dead Cell Stain</td>
			<td>Invitrogen</td>
			<td>S34857</td>
			<td>blue-fluorescent nucleic acid stain</td>
		</tr>
		<tr>
			<td>Transfer Pipet</td>
			<td>Falcon</td>
			<td>357575</td>
			<td>Falcon&#8482; Plastic Disposable Transfer Pipets</td>
		</tr>
		<tr>
			<td>Valve Control System</td>
			<td>Warner Instruments</td>
			<td>VCS-8</td>
			<td>System for dynamic stimulation recordings</td>
		</tr>
		<tr>
			<td>Vibratome VT1000 S</td>
			<td>Leica</td>
			<td>VT1000 S</td>
			<td></td>
		</tr>
		<tr>
			<td>Water bath</td>
			<td>Fisher Scientific</td>
			<td>FSGPD02</td>
			<td>Fisherbrand Isotemp General Purpose Deluxe Water Bath GPD 02</td>
		</tr>
	</tbody>
</table>

observing islet function and islet-immune cell interactions in live pancreatic tissue slices

Live pancreatic tissue slices allow for the study of islet physiology and function in the context of an intact islet microenvironment. Slices are prepared from live human and mouse pancreatic tissue embedded in agarose and cut using a vibratome. This method allows for the tissue to maintain viability and function in addition to preserving underlying pathologies such as type 1 (T1D) and type 2 diabetes (T2D). The slice method enables new directions in the study of the pancreas through the maintenance of the complex structures and various intercellular interactions that comprise the endocrine and exocrine tissues of the pancreas. This protocol demonstrates how to perform staining and time-lapse microscopy of live endogenous immune cells within pancreatic slices along with assessments of islet physiology. Further, this approach can be refined to discern immune cell populations specific for islet cell antigens using major histocompatibility complex-multimer reagents.

This protocol will yield live pancreatic tissue slices suitable for both functionality studies and immune cell recordings. Slice appearance in both brightfield and under reflected light are shown in Figure 1A,B. As discussed, islets can be found in slices using reflected light due to their increased granularity that occurs because of their insulin content (Figure 1C) and are clearly observed compared to the background tissue when reflected light...

Watch this Scientific Journal Video about Observing Islet Function and Islet-Immune Cell Interactions in Live Pancreatic Tissue Slices at JoVE.com

Observing Islet Function and Islet-Immune Cell Interactions in Live Pancreatic Tissue Slices

This study presents the application of live pancreatic tissue slices to the study of islet physiology and islet-immune cell interactions.

Live pancreatic tissue slices allow for the study of islet physiology and function in the context of an intact islet microenvironment. Slices are prepared ...

observing-islet-function-islet-immune-cell-interactions-live

Microsoft Bing

Research

JoVE Journal

Immunology and Infection

3.8K Views.  University of Florida. This study presents the application of live pancreatic tissue slices to the study of islet physiology and islet-immune cell interactions. 

Video: Observing Islet Function and Islet-Immune Cell Interactions in Live Pancreatic Tissue Slices

Use of an Optical Trap for Study of Host-Pathogen Interactions for Dynamic Live Cell Imaging

Dynamic live cell imaging allows direct visualization of real-time interactions between cells of the immune system1, 2; however, the lack of spatial and temporal control between the phagocytic cell and microbe has rendered focused observations into the initial interactions of host response to pathogens difficult. Historically, intercellular contact events such as phagocytosis3 have been imaged by mixing two cell types, and then continuously scanning the field-of-view to find serendipitous intercellular contacts at the appropriate stage of interaction. The stochastic nature of these events renders this process tedious, and it is difficult to observe early or fleeting events in cell-cell contact by this approach. This method requires finding cell pairs that are on the verge of contact, and observing them until they consummate their contact, or do not. To address these limitations, we use optical trapping as a non-invasive, non-destructive, but fast and effective method to position cells in culture.
Optical traps, or optical tweezers, are increasingly utilized in biological research to capture and physically manipulate cells and other micron-sized particles in three dimensions4. Radiation pressure was first observed and applied to optical tweezer systems in 19705, 6, and was first used to control biological specimens in 19877. Since then, optical tweezers have matured into a technology to probe a variety of biological phenomena8-13.
We describe a method14 that advances live cell imaging by integrating an optical trap with spinning disk confocal microscopy with temperature and humidity control to provide exquisite spatial and temporal control of pathogenic organisms in a physiological environment to facilitate interactions with host cells, as determined by the operator. Live, pathogenic organisms like Candida albicans and Aspergillus fumigatus, which can cause potentially lethal, invasive infections in immunocompromised individuals15, 16 (e.g. AIDS, chemotherapy, and organ transplantation patients), were optically trapped using non-destructive laser intensities and moved adjacent to macrophages, which can phagocytose the pathogen. High resolution, transmitted light and fluorescence-based movies established the ability to observe early events of phagocytosis in living cells. To demonstrate the broad applicability in immunology, primary T-cells were also trapped and manipulated to form synapses with anti-CD3 coated microspheres in vivo, and time-lapse imaging of synapse formation was also obtained. By providing a method to exert fine spatial control of live pathogens with respect to immune cells, cellular interactions can be captured by fluorescence microscopy with minimal perturbation to cells and can yield powerful insight into early responses of innate and adaptive immunity.

A method is described to individually select, manipulate, and image live pathogens using an optical trap coupled to a spinning disk microscope. The optical trap provides spatial and temporal control of organisms and places them adjacent to host cells. Fluorescence microscopy captures dynamic intercellular interactions with minimal perturbation to cells.

Dynamic live cell imaging allows direct visualization of real-time interactions between cells of the immune system1, 2; however, the lack of spatial and ...

Single Cell Measurements of Vacuolar Rupture Caused by Intracellular Pathogens

Shigella flexneri are pathogenic bacteria that invade host cells entering into an endocytic vacuole. Subsequently, the rupture of this membrane-enclosed compartment allows bacteria to move within the cytosol, proliferate and further invade neighboring cells. Mycobacterium tuberculosis is phagocytosed by immune cells, and has recently been shown to rupture phagosomal membrane in macrophages. We developed a robust assay for tracking phagosomal membrane disruption after host cell entry of Shigella flexneri or Mycobacterium tuberculosis. The approach makes use of CCF4, a FRET reporter sensitive to &beta;-lactamase that equilibrates in the cytosol of host cells. Upon invasion of host cells by bacterial pathogens, the probe remains intact as long as the bacteria reside in membrane-enclosed compartments. After disruption of the vacuole, &beta;-lactamase activity on the surface of the intracellular pathogen cleaves CCF4 instantly leading to a loss of FRET signal and switching its emission spectrum. This robust ratiometric assay yields accurate information about the timing of vacuolar rupture induced by the invading bacteria, and it can be coupled to automated microscopy and image processing by specialized algorithms for the detection of the emission signals of the FRET donor and acceptor. Further, it allows investigating the dynamics of vacuolar disruption elicited by intracellular bacteria in real time in single cells. Finally, it is perfectly suited for high-throughput analysis with a spatio-temporal resolution exceeding previous methods. Here, we provide the experimental details of exemplary protocols for the CCF4 vacuolar rupture assay on HeLa cells and THP-1 macrophages for time-lapse experiments or end points experiments using Shigella flexneri as well as multiple mycobacterial strains such as Mycobacterium marinum, Mycobacterium bovis, and Mycobacterium tuberculosis.

We describe a method for tracking the endomembrane rupture elicited by the intracellular bacteria Shigella flexneri and Mycobacterium tuberculosis upon host cell invasion. Our assay makes use of CCF4, a host cytoplasmic FRET probe in live or fixed cells. This reporter is degraded by an enzyme activity present on the bacterial surface.

Shigella flexneri are pathogenic bacteria that invade host cells entering into an endocytic vacuole. Subsequently, the rupture of this membrane-enclosed ...

Visualizing Protein-DNA Interactions in Live Bacterial Cells Using Photoactivated Single-molecule Tracking

Protein-DNA interactions are at the heart of many fundamental cellular processes. For example, DNA replication, transcription, repair, and chromosome organization are governed by DNA-binding proteins that recognize specific DNA structures or sequences. In vitro experiments have helped to generate detailed models for the function of many types of DNA-binding proteins, yet, the exact mechanisms of these processes and their organization in the complex environment of the living cell remain far less understood. We recently introduced a method for quantifying DNA-repair activities in live Escherichia coli cells using Photoactivated Localization Microscopy (PALM) combined with single-molecule tracking. Our general approach identifies individual DNA-binding events by the change in the mobility of a single protein upon association with the chromosome. The fraction of bound molecules provides a direct quantitative measure for the protein activity and abundance of substrates or binding sites at the single-cell level. Here, we describe the concept of the method and demonstrate sample preparation, data acquisition, and data analysis procedures.

Photoactivated localization microscopy (PALM) combined with single-molecule tracking allows direct observation and quantification of protein-DNA interactions in live Escherichia coli cells.

Protein-DNA interactions are at the heart of many fundamental cellular processes. For example, DNA replication, transcription, repair, and chromosome ...

Evaluation of the Efficacy And Toxicity of RNAs Targeting HIV-1 Production for Use in Gene or Drug Therapy

Small RNA therapies targeting post-integration steps in the HIV-1 replication cycle are among the top candidates for gene therapy and have the potential to be used as drug therapies for HIV-1 infection. Post-integration inhibitors include ribozymes, short hairpin (sh) RNAs, small interfering (si) RNAs, U1 interference (U1i) RNAs and RNA aptamers. Many of these have been identified using transient co-transfection assays with an HIV-1 expression plasmid and some have advanced to clinical trials. In addition to measures of efficacy, small RNAs have been evaluated for their potential to affect the expression of human RNAs, alter cell growth and/or differentiation, and elicit innate immune responses. In the protocols described here, a set of transient transfection assays designed to evaluate the efficacy and toxicity of RNA molecules targeting post-integration steps in the HIV-1 replication cycle are described. We have used these assays to identify new ribozymes and optimize the format of shRNAs and siRNAs targeting HIV-1 RNA. The methods provide a quick set of assays that are useful for screening new anti-HIV-1 RNAs and could be adapted to screen other post-integration inhibitors of HIV-1 replication.

Methods to evaluate the efficacy and toxicity of RNA molecules targeting post-integration steps of the HIV-1 replication cycle are described. These methods are useful for screening new molecules and optimizing the format of existing ones.

Small RNA therapies targeting post-integration steps in the HIV-1 replication cycle are among the top candidates for gene therapy and have the potential ...

Precision-cut Mouse Lung Slices to Visualize Live Pulmonary Dendritic Cells

Inhalation of allergens and pathogens elicits multiple changes in a variety of immune cell types in the lung. Flow cytometry is a powerful technique for quantitative analysis of cell surface proteins on immune cells, but it provides no information on the localization and migration patterns of these cells within the lung. Similarly,&#160;chemotaxis assays can be performed to study the potential of cells to respond to chemotactic factors in vitro, but these assays do not reproduce the complex environment of the intact lung. In contrast to these aforementioned techniques, the location of individual cell types within the lung can be readily visualized by generating Precision-cut Lung Slices (PCLS), staining them with commercially available, fluorescently tagged antibodies, and visualizing the sections by confocal microscopy. PCLS can be used for both live and fixed lung tissue, and the slices can encompass areas as large as a cross section of an entire lobe. We have used this protocol to successfully visualize the location of a wide variety of cell types in the lung, including distinct types of dendritic cells, macrophages, neutrophils, T cells and B cells, as well as structural cells such as lymphatic, endothelial, and epithelial cells. The ability to visualize cellular interactions, such as those between dendritic cells and T cells, in live, three-dimensional lung tissue, can reveal how cells move within the lung and interact with one another at steady state and during inflammation. Thus, when used in combination with other procedures, such as flow cytometry and quantitative PCR, PCLS can contribute to a comprehensive understanding of cellular events that underlie allergic and inflammatory diseases of the lung.

We describe a method for generating Precision-cut Lung Slices (PCLS) and immunostaining them to visualize the localization of various immune cell types in the lung. Our protocol can be extended to visualize the location and function of many different cell types under a variety of conditions.

Inhalation of allergens and pathogens elicits multiple changes in a variety of immune cell types in the lung. Flow cytometry is a powerful technique for ...

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture

Histocultures allow studying intercellular interactions within human tissues, and they can be employed to model host-pathogen interactions under controlled laboratory conditions. Ex vivo infection of human tissues with human immunodeficiency virus (HIV), among other viruses, has been successfully used to investigate early disease pathogenesis, as well as a platform to test the efficacy and toxicity of antiviral drugs. In the present protocol, we explain how to process and infect with HIV-1 tissue explants from human tonsils and cervical mucosae, and maintain them in culture on top of gelatin sponges at the liquid-air interface for about two weeks. This non-polarized culture setting maximizes access to nutrients in culture medium and oxygen, although progressive loss of tissue integrity and functional architectures remains its main limitation. This method allows monitoring HIV-1 replication and pathogenesis using several techniques, including immunoassays, qPCR, and flow cytometry. Of importance, the physiologic variability between tissue donors, as well as between explants from different areas of the same specimen, may significantly affect experimental results. To ensure result reproducibility, it is critical to use an adequate number of explants, technical replicates, and donor-matched control conditions to normalize the results of the experimental treatments when compiling data from multiple experiments (i.e., conducted using tissue from different donors) for statistical analysis.

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture

Infection of human tissues with human immunodeficiency virus (HIV) ex vivo provides a valuable 3D model of virus pathogenesis. Here, we describe a protocol to process and infect tissue specimens from human tonsils and female genital mucosae with HIV-1 and maintain them in culture at the liquid-air interface.

Histocultures allow studying intercellular interactions within human tissues, and they can be employed to model host-pathogen interactions under ...

Electrochemiluminescence Assays for Human Islet Autoantibodies

Pinpointing islet autoantibodies associated with type 1 diabetes (T1D) leads the way to project and deter this disease in the general population. A novel ECL assay is a nonradioactive fluid phase assay for islet autoantibodies with higher sensitivity and specificity than the current 'gold' standard radio-binding assay (RBA). ECL assays can more precisely define the onset of presymptomatic T1D by distinguishing the high-risk, high-affinity autoantibodies from the low-risk, low-affinity autoantibodies generated in RBAs, and conventional enzyme-linked immunosorbent assays (ELISA). The antigen protein used in this ECL assay is labeled with Sulfo-tag and Biotin, respectively. Each ECL autoantibody assay that uses a particular antigen protein needs an optimization step before it can be used for laboratory application. This step is especially vital in determining the requirements for serum acid treatments, concentrations, and ratios of the two different antigens labeled with Sulfo-tag and Biotin. To perform the assay, serum samples are mixed with Sulfo-tag-conjugated and biotinylated capture antigen protein in phosphate buffered solution (PBS), containing 5% Bovine Serum Albumin (BSA). Afterwards, the samples are incubated overnight at 4 &#176;C. The same day, a streptavidin-coated plate is prepared with blocker buffer and incubated overnight at 4 &#176;C. On the second day, wash the streptavidin plate and transfer the serum-antigen mixture onto the plate. Place the plate on the plate shaker, set it at low speed, and incubate at room temperature for 1 h. Subsequently, the plate is washed again, and reader buffer is added. The plate is then counted on the plate reader machine. The results are conveyed through an index, which is generated from internal standard positive and negative control serum samples.

Here, we presented the methods to detect human islet autoantibodies using electrochemiluminescence (ECL) assays. The protocol, used to predict type 1 diabetes, can be expanded upon to detect autoantibodies for other autoimmune diseases.

Pinpointing islet autoantibodies associated with type 1 diabetes (T1D) leads the way to project and deter this disease in the general population. A novel ...

A Murine Pancreatic Islet Cell-based Screening for Diabetogenic Environmental Chemicals

Exposure to certain environmental chemicals in human and animals has been found to cause cellular damage of the pancreatic &#946; cells which will lead to the development of type 2 diabetes mellitus (T2DM). Although the mechanisms for the chemical-induced &#946; cell damage were unclear and likely to be complex, one recurring finding is that these chemicals induce oxidative stress leading to the generation of excessive reactive oxygen species (ROS) which induce damage to the &#946; cell. To identify potential diabetogenic environmental chemicals, we isolated pancreatic islet cells from C57BL/6 mice and cultured islet cells in 96-well cell culture plates; then, the islet cells were dosed with chemicals and the ROS generation was detected by 2',7'-dichlorofluorescein (DCFH-DA) fluorescent dye. Using this method, we found that bisphenol A (BPA), Benzo[a]pyrene (BaP), and polychlorinated biphenyls (PCBs), could induce high levels of ROS, suggesting that they may potentially induce damage in islet cells. This method should be useful for screening diabetogenic xenobiotics. In addition, the cultured islet cells may also be adapted for in vitro analysis of chemical-induced toxicity in pancreatic cells.

Here we present a protocol to isolate mouse pancreatic islet cells for screening the ROS inductions by the xenobiotics in order to identify the potential diabetogenic xenobiotic chemicals.

Exposure to certain environmental chemicals in human and animals has been found to cause cellular damage of the pancreatic &#946; cells which will lead to ...

Determination of Regulatory T Cell Subsets in Murine Thymus, Pancreatic Draining Lymph Node and Spleen Using Flow Cytometry

Our immune system consists of a number and variety of immune cells including regulatory T cells (Treg) cells. Treg cells can be divided into two subsets, thymic derived Treg (tTreg) cells and peripherally induced Treg (pTreg) cells. They are present in different organs of our body and can be distinguished by specific markers, such as Helios and Neuropilin 1. It has been reported that tTreg cells are functionally more suppressive than pTreg cells. Therefore, it is important to determine the proportion of both tTreg and pTreg cells when investigating heterogeneous cell populations. Herein, we collected thymic glands, pancreatic draining lymph nodes and spleens from normoglycemic non-obese diabetic mice to distinguish tTreg cells from pTreg cells using flow cytometry. We manually prepared single cell suspensions from these organs. Fluorochrome conjugated surface CD4, CD8, CD25, and Neuropilin 1 antibodies were used to stain the cells. They were kept in the fridge overnight. On the next day, the cells were stained with fluorochrome conjugated intracellular Foxp3 and Helios antibodies. These markers were used to characterize the two subsets of Treg cells. This protocol demonstrates a simple but practical way to prepare single cells from murine thymus, pancreatic draining lymph node and spleen and use them for subsequent flow cytometric analysis.

Herein, we present a protocol to prepare single cells from murine thymus, pancreatic draining lymph node and spleen to further study these cells using flow cytometry. In addition, this protocol was used for determining the subsets of regulatory T cells using flow cytometry.

Our immune system consists of a number and variety of immune cells including regulatory T cells (Treg) cells. Treg cells can be divided into two subsets, ...

Live-Cell Fluorescence Microscopy to Investigate Subcellular Protein Localization and Cell Morphology Changes in Bacteria

Investigations of factors influencing cell division and cell shape in bacteria are commonly performed in conjunction with high-resolution fluorescence microscopy as observations made at a population level may not truly reflect what occurs at a single cell level. Live-cell timelapse microscopy allows investigators to monitor the changes in cell division or cell morphology which provide valuable insights regarding subcellular localization of proteins and timing of gene expression, as it happens, to potentially aid in answering important biological questions. Here, we describe our protocol to monitor phenotypic changes in Bacillus subtilis and Staphylococcus aureus using a high-resolution deconvolution microscope. The objective of this report is to provide a simple and clear protocol that can be adopted by other investigators interested in conducting fluorescence microscopy experiments to study different biological processes in bacteria as well as other organisms.

This article provides a step-by-step guide to investigate protein subcellular localization dynamics and to monitor morphological changes using high-resolution fluorescence microscopy in Bacillus subtilis and Staphylococcus aureus.

Investigations of factors influencing cell division and cell shape in bacteria are commonly performed in conjunction with high-resolution fluorescence ...