We acknowledge Monash Micro Imaging for the use of Nikon C1 upright confocal laser scanning microscope and the Monash Histology Platform for the processing of kidney tissue.

This method enables detection of pan ecDNA from all forms of cell death. The same method and antibodies are used for human kidney biopsy tissue (from step 4). All animal and human subjects had Ethics approval from Monash University, and Monash Health, Clayton, Victoria, Australia.
1. Staining for ecDNA with DAPI and &#946;-Actin
<ol>
	<li>Induce a 20 day model of anti-myeloperoxidase glomerulonephritis (anti-MPO-GN) in 8-10 week old C57/Bl6 mice, with controls9.
	<ol>...

<ol>
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A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Programmed+cell+death+as+a+defence+against+infection.">Programmed cell death as a defence against infection.</a> Nat Rev Immunol. 17 (3), 151-164 (2017).</li><li>Brinkmann, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neutrophil+extracellular+traps+kill+bacteria.">Neutrophil extracellular traps kill bacteria.</a> Science. 303 (5663), 1532-1535 (2004).</li><li>Wyllie, A. H., Kerr, J. F., Currie, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+death:+the+significance+of+apoptosis.">Cell death: the significance of apoptosis.</a> International Review of Cytology. 68, 251-306 (1980).</li><li>Fiers, W., Beyaert, R., Declercq, W., Vandenabeele, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=More+than+one+way+to+die:+apoptosis,+necrosis+and+reactive+oxygen+damage.">More than one way to die: apoptosis, necrosis and reactive oxygen damage.</a> Oncogene. 18 (54), 7719-7730 (1999).</li><li>Pasparakis, M., Vandenabeele, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Necroptosis+and+its+role+in+inflammation.">Necroptosis and its role in inflammation.</a> Nature. 517 (7534), 311-320 (2015).</li><li>Fink, S. L., Cookson, B. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Caspase-1-dependent+pore+formation+during+pyroptosis+leads+to+osmotic+lysis+of+infected+host+macrophages.">Caspase-1-dependent pore formation during pyroptosis leads to osmotic lysis of infected host macrophages.</a> Cellular Microbiology. 8 (11), 1812-1825 (2006).</li><li>Ooi, J. D., Gan, P. Y., Odobasic, D., Holdsworth, S. R., Kitching, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=T+cell+mediated+autoimmune+glomerular+disease+in+mice.">T cell mediated autoimmune glomerular disease in mice.</a> Current Protocols in Immunology. 107, 15.27.11-15.27.19 (2014).</li><li>Ruth, A. 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=Anti-neutrophil+cytoplasmic+antibodies+and+effector+CD4++cells+play+nonredundant+roles+in+anti-myeloperoxidase+crescentic+glomerulonephritis.">Anti-neutrophil cytoplasmic antibodies and effector CD4+ cells play nonredundant roles in anti-myeloperoxidase crescentic glomerulonephritis.</a> Journal of the American Society of Nephrology. 17 (7), 1940-1949 (2006).</li><li>Nagler, M., Insam, H., Pietramellara, G., Ascher-Jenull, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extracellular+DNA+in+natural+environments:+features,+relevance+and+applications.">Extracellular DNA in natural environments: features, relevance and applications.</a> Applied Microbiology and Biotechnology. 102 (15), 6343-6356 (2018).</li><li>Burnham, 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=Urinary+cell-free+DNA+is+a+versatile+analyte+for+monitoring+infections+of+the+urinary+tract.">Urinary cell-free DNA is a versatile analyte for monitoring infections of the urinary tract.</a> Nature Communications. 9 (1), 2412 (2018).</li><li>Gobe, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+apoptosis+in+kidney+tissue+sections.">Identification of apoptosis in kidney tissue sections.</a> Methods in Molecular Biology. 466, 175-192 (2009).</li><li>Olander, M., Handin, N., Artursson, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Image-Based+Quantification+of+Cell+Debris+as+a+Measure+of+Apoptosis.">Image-Based Quantification of Cell Debris as a Measure of Apoptosis.</a> Analytical Chemistry. 91 (9), 5548-5552 (2019).</li><li>Arganda-Carreras, I., 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=Trainable+Weka+Segmentation:+a+machine+learning+tool+for+microscopy+pixel+classification.">Trainable Weka Segmentation: a machine learning tool for microscopy pixel classification.</a> Bioinformatics. 33 (15), 2424-2426 (2017).</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>Apel, F., Zychlinsky, A., Kenny, E. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+neutrophil+extracellular+traps+in+rheumatic+diseases.">The role of neutrophil extracellular traps in rheumatic diseases.</a> Nature Reviews Rheumatology. 14 (8), 467-475 (2018).</li><li>Chapman, E. 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=Caught+in+a+Trap?+Proteomic+Analysis+of+Neutrophil+Extracellular+Traps+in+Rheumatoid+Arthritis+and+Systemic+Lupus+Erythematosus.">Caught in a Trap? Proteomic Analysis of Neutrophil Extracellular Traps in Rheumatoid Arthritis and Systemic Lupus Erythematosus.</a> Frontiers in Immunology. 10, 423 (2019).</li><li>Oliveira, V. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sudan+Black+B+treatment+reduces+autofluorescence+and+improves+resolution+of+in+situ+hybridization+specific+fluorescent+signals+of+brain+sections.">Sudan Black B treatment reduces autofluorescence and improves resolution of in situ hybridization specific fluorescent signals of brain sections.</a> Histology &amp; Histopathology. 25 (8), 1017-1024 (2010).</li><li>Kessenbrock, 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=Netting+neutrophils+in+autoimmune+small-vessel+vasculitis.">Netting neutrophils in autoimmune small-vessel vasculitis.</a> Nature Medicine. 15 (6), 623-625 (2009).</li><li>Schreiber, 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=Necroptosis+controls+NET+generation+and+mediates+complement+activation,+endothelial+damage,+and+autoimmune+vasculitis.">Necroptosis controls NET generation and mediates complement activation, endothelial damage, and autoimmune vasculitis.</a> Proceedings of the National Academy of Sciences of the United States of America. 114 (45), E9618-E9625 (2017).</li><li>Antonelou, M., Perea Ortega, L., Harvey, J., Salama, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anti-myeloperoxidase+antibody+positivity+in+patients+without+primary+systemic+vasculitis.">Anti-myeloperoxidase antibody positivity in patients without primary systemic vasculitis.</a> Clinical and Experimental Rheumatology. 37 (2), 86-89 (2019).</li></ol>

Multiple protocols exist that measure proinflammatory markers in the serum and urine of both patients and mouse models of glomerulonephritis. This described protocol allows analysis of the products of cell death (ecDNA, NETs and ecMPO) within the glomerulus directly. The most crucial steps in this protocol is the tissue preparation and imaging. The major restricting element of using a fluorescent staining method for analysis is the tissue autofluorescence. Formalin fixed paraffin tissue is subject to autofluorescence tha...

Myeloperoxidase anti neutrophil cytoplasmic antibody associated vasculitis (MPO-AAV) is an autoimmune disease that results in renal failure from pathological glomerular injury with considerable cell death and release of deoxyribonucleic acid (DNA)1,2. DNA can activate the immune system by acting as a danger signal. Under normal healthy conditions, the nuclear location of DNA offers protection from exposure to the immune system. Self-DNA that is released extracellularly during either pathogenic processes or autoimmunity is seen by the immune system as a potent proinflammatory damage associated molecular self-protein (DAMP)3. Extra cellular DNA (ecDNA) is released from dying cells through several distinct mechanisms that are governed by distinct biochemical pathways, such as apoptosis, necroptosis neutrophil extracellular trap formation (NETs), necrosis or pyroptosis4,5,6,7,8.
We describe herein methods to stain and measure ecDNA released from dying cells in sections of formalin fixed paraffin embedded (FFPE) kidneys from experimental anti-MPO GN and kidney biopsies from patients with MPO-AAV9,10. Multiple methods exist for the detection of circulating double stranded DNA (dsDNA) and DNA complexes from both serum and urine and from in vitro assays11,12. These methods, although accurate in determining the amount of ecDNA, do not determine where the ecDNA is released anatomically. There are methods that describe specific measurement of ecDNA such as tunel for apoptosis and measurement of cell debris13,14. There is no method that describes measuring ecDNA culminated from all forms of cell death in FFPE kidneys where the pathological damage occurs. This is important to determine if experimental therapeutic treatments are clearing the ecDNA from the sites of pathological injury in the actual target organ.
The acquisition of multiple images from kidney samples creates a high volume of data that is analyzed commonly by one single user. This is labor intensive, time consuming and can be subject to unreliable reproducibility by other users, due to user bias. Trainable Weka segmentation is an open-source software plugin for ImageJ that uses cutting edge bioinformatic tools to classify pixels using machine learning algorithms15,16. This method is &#34;trainable&#34; whereby it learns from the user&#39;s classification of segments of pixels and applies the new learnt classification to other images. This method relies on common analysis tools within the ImageJ program that are used to &#34;classify&#34; each pixel in a segment as belonging to a specific &#34;class&#34;. Once the program learns the &#34;classifiers&#34;, they can be used to identify other similar classified segments within the same image. This model is then saved and applied to other sets of images within the same experiment.
Current obstacles to determining ecDNA in situ in kidney sections is the endogenous autofluorescence from fixation in formalin and the labor-intensive analysis of the images. We describe here how to quench this autofluorescence, detect ecDNA, and use supervised machine learning for high throughput measurement of ecDNA. We have previously published the measurement of NETs and extracellular MPO (ecMPO) using a macro in ImageJ, we now demonstrate semi automation of these methods using supervised machine learning1. We demonstrate the adaptability of the machine learning tool, to classify an alternative stain for NETs and ecMPO within the same image. These staining methods described here for detecting ecDNA, NETs and ecMPO can be translated to other solid organs and diseases where ecDNA, NETS and ecMPO plays a role in perpetuating disease such as rheumatoid arthritis and lupus17,18.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>SIGMA</td>
			<td>A2153</td>
			<td>5% and 1% solutions are made up in PBS, can be made in bulk and frozen- discard once thawed.</td>
		</tr>
		<tr>
			<td>Chicken anti Goat IgG (H+L) cross absorbed antibody Alexa Fluor 594</td>
			<td>ThermoFisher Scientific</td>
			<td>A-21468</td>
			<td>Spin in mini centrifuge for 1 minute prior to use to avoid any free conjugate in your antibody cocktail</td>
		</tr>
		<tr>
			<td>Chicken anti mouse IgG (H+L) cross absorbed antibody, Alex Fluor 647</td>
			<td>ThermoFisher Scientific</td>
			<td>A-121468</td>
			<td>Spin in mini centrifuge for 1 minute prior to use to avoid any free conjugate in your antibody cocktail</td>
		</tr>
		<tr>
			<td>Chicken anti rabbit IgG (H+L) Cross absorbed antibody Alexa Fluor 488</td>
			<td>ThermoFisher Scientific</td>
			<td>A-21441</td>
			<td>Spin in mini centrifuge for 1 minute prior to use to avoid any free conjugate in your antibody cocktail</td>
		</tr>
		<tr>
			<td>Chicken sera</td>
			<td>SIGMA</td>
			<td>C5405</td>
			<td>Made up in 1%BSA/PBS</td>
		</tr>
		<tr>
			<td>Coverslips 24 x60 mm</td>
			<td>Azerscientific</td>
			<td>ES0107222</td>
			<td>#1.5 This is not standard thickness- designed for use in confocal microscopy</td>
		</tr>
		<tr>
			<td>EDTA 10mM</td>
			<td>SIGMA</td>
			<td>E6758</td>
			<td>Add TRIS and EDTA together in distilled water and pH to 9, for antigen retrieval, can be made up in a 10x Solution</td>
		</tr>
		<tr>
			<td>Ethanol 30%, 70% and 100%</td>
			<td>Chem Supply</td>
			<td>UN1170</td>
			<td>Supplied as 100% undenatured ethanol- dilute to 30% and 70% using distilled water</td>
		</tr>
		<tr>
			<td>Formaldehyde, 4% (10% Neutral buffered Formalin)</td>
			<td>TRAJAN</td>
			<td>NBF-500</td>
			<td>Kidney is put into a 5ml tube containing 3ml of formalin for 16 hours at RT, formalin should be used in a fume hood</td>
		</tr>
		<tr>
			<td>Glass histology slides- Ultra Super Frost, Menzel Glaze, 25x75 x1.0mm</td>
			<td>TRAJAN</td>
			<td>J3800AM4</td>
			<td>Using positive charged coated slides is essential. We do not recommend using poly-L-lysine for coating slides as tissue dislodges from slides during the antigen retrieval step</td>
		</tr>
		<tr>
			<td>Goat anti human/mouse MPO antibody</td>
			<td>R&#38;D</td>
			<td>AF3667</td>
			<td>Aliquot and freeze at minus 80 degrees upon arrival</td>
		</tr>
		<tr>
			<td>Histosol</td>
			<td>Clini Pure</td>
			<td>CPL HISTOSOL 08</td>
			<td>Used neat, in 200ml staining rack containers, use in a fume hood</td>
		</tr>
		<tr>
			<td>Hydrophobic pen</td>
			<td>VECTOR Labs</td>
			<td>H-400</td>
			<td>Use to draw circle around kidney tissue</td>
		</tr>
		<tr>
			<td>Mouse anti human/mouse Peptidyl arginase 4 (PAD4)</td>
			<td>ABCAM</td>
			<td>ab128086</td>
			<td>Aliquot and freeze at minus 80 degrees upon arrival</td>
		</tr>
		<tr>
			<td>Nikon C1 confocal scanning laser head attached to Nikon Ti-E inverted Microscope</td>
			<td>Coherent Scientific</td>
			<td></td>
			<td>Aliquot and freeze at minus 80 degrees upon arrival</td>
		</tr>
		<tr>
			<td>Phosphate Buffered Saline</td>
			<td>SIGMA</td>
			<td>P38135</td>
			<td>0.01M PB/0.09% NaCl Make up 5L at a time</td>
		</tr>
		<tr>
			<td>Pressure Cooker 6L Tefal secure 5 Neo stainless</td>
			<td>Tefal</td>
			<td>GSA-P2530738</td>
			<td>Purchased at local homeware store</td>
		</tr>
		<tr>
			<td>Prolong Gold DAPI</td>
			<td>Life Technologies</td>
			<td>P36962</td>
			<td>Apply drops directly to coverslip</td>
		</tr>
		<tr>
			<td>Rabbit anti human/mouse Beta Actin antibody</td>
			<td>ABCAM</td>
			<td>ab8227</td>
			<td>Aliquot and freeze at minus 80 degrees upon arrival</td>
		</tr>
		<tr>
			<td>Rabbit anti human/mouse H3Cit antibody</td>
			<td>ABCAM</td>
			<td>ab5103</td>
			<td>Aliquot and freeze at minus 80 degrees upon arrival</td>
		</tr>
		<tr>
			<td>Staining rack 24 slides</td>
			<td>ProScitech</td>
			<td>H4465</td>
			<td>Staining rack chosen has to be able to withstand boiling under pressure and incubation in 60 degree oven</td>
		</tr>
		<tr>
			<td>Sudan Black B</td>
			<td>SIGMA</td>
			<td>199664</td>
			<td>0.3% Add 3g to a 1L bottle in 70% Ethanol, filter and protect from the light- stable for 6 months at room temperature</td>
		</tr>
		<tr>
			<td>Tris 10mM</td>
			<td>SIGMA</td>
			<td>T4661</td>
			<td>Add TRIS and EDTA together in distilled water and pH to 9, for antigen retrieval, can be made up in a 10x solution</td>
		</tr>
		<tr>
			<td>Xylene</td>
			<td>Trajan</td>
			<td>XL005/20</td>
			<td>Must be use used in a fume hood</td>
		</tr>
	</tbody>
</table>

supervised machine learning for semi-quantification of extracellular dna in glomerulonephritis

Glomerular cell death is a pathological feature of myeloperoxidase anti neutrophil cytoplasmic antibody associated vasculitis (MPO-AAV). Extracellular deoxyribonucleic acid (ecDNA) is released during different forms of cell death including apoptosis, necrosis, necroptosis, neutrophil extracellular traps (NETs) and pyroptosis. Measurement of this cell death is time consuming with several different biomarkers required to identify the different biochemical forms of cell death. Measurement of ecDNA is generally conducted in serum and urine as a surrogate for renal damage, not in the actual target organ where the pathological injury occurs. The current difficulty in investigating ecDNA in the kidney is the lack of methods for formalin fixed paraffin embedded tissue (FFPE) both experimentally and in archived human kidney biopsies. This protocol provides a summary of the steps required to stain for ecDNA in FFPE tissue (both human and murine), quench autofluorescence and measure the ecDNA in the resulting images using a machine learning tool from the publicly available open source ImageJ plugin trainable Weka segmentation. Trainable Weka segmentation is applied to ecDNA within the glomeruli where the program learns to classify ecDNA. This classifier is applied to subsequent acquired kidney images, reducing the need for manual annotations of each individual image. The adaptability of the trainable Weka segmentation is demonstrated further in kidney tissue from experimental murine anti-MPO glomerulonephritis (GN), to identify NETs and ecMPO, common pathological contributors to anti-MPO GN. This method provides objective analysis of ecDNA in kidney tissue that demonstrates clearly the efficacy in which the trainable Weka segmentation program can distinguish ecDNA between healthy normal kidney tissue and diseased kidney tissue. This protocol can easily be adapted to identify ecDNA, NETs and ecMPO in other organs.

These images represent the multiple steps required to successfully use trainable Weka segmentation to minimize the labor-intensive manual measurement of ecDNA in fluorescently stained FFPE kidney tissue from a mouse with induced anti-MPO GN. These steps are summarized in Figure 1 and Figure 2 with images taken directly from the Weka segmentation program, outlining every step in the analysis process. Measurements from this analysi...

Watch this Scientific Journal Video about Supervised Machine Learning for Semi-Quantification of Extracellular DNA in Glomerulonephritis at JoVE.com

Supervised Machine Learning for Semi-Quantification of Extracellular DNA in Glomerulonephritis

Extracellular DNA (ecDNA) released during cell death is proinflammatory and contributes to inflammation. Measurement of ecDNA at the site of injury can determine the efficacy of therapeutic treatment in the target organ. This protocol describes the use of a machine learning tool to automate measurement of ecDNA in kidney tissue.

Glomerular cell death is a pathological feature of myeloperoxidase anti neutrophil cytoplasmic antibody associated vasculitis (MPO-AAV). Extracellular ...

Glomerulonephritis causes pathological glomerular injury with considerable cell death and extracellular DNA release. This protocol enables the visualization of extracellular DNA at the site of release during pathological injury. The advantage of this technique is that it measures extracellular DNA from cell death in the kidney.As opposed to serum or urine, extracellular DNA measurement is a surrogate marker for pathological damage. The significance of this method is that both the extracellular DNA staining and image analysis are easily transferrable to other autoimmune diseases such as rheumatoid arthritis and lupus. This method requires a basic knowledge of kidney histology.To enable the accurate detection of glomerular extracellular DNA, the researcher must be able to correctly identify glomeruli. For extracellular DNA staining, first heat the samples of interest in a slide rack in 60 degrees Celsius for 60 minutes before immersing the slides in two 40-minute changes of solvent in a fume hood. After the second immersion, rehydrate the samples two times in 100%ethanol and one time in 70%ethanol for five minutes per treatment.After the last treatment, use tongs to place the slides into boiling antigen retrieval solution in a pressure cooker on high for 10 minutes. After unmasking the antigen epitopes, transfer the pressure cooker from heat into a sink and immediately run cold tap water over the lid. Allow the slides to equilibrate for 20 minutes in the antigen retrieval solution before washing the samples two times in 0.01 molar PBS on an orbital shaker for five minutes per wash.After the second wash, use a hydrophobic pen to draw circles around the kidney tissue samples and block any nonspecific staining with 60 microliters of 10%chicken serum in 5%bovine serum albumin for 30 minutes at room temperature. At the end of the incubation, carefully replace the blocking solution with 60 microliters of the primary antibody of interest in a humidity chamber overnight at four degrees Celsius. The next morning, wash the slides on an orbital shaker in PBS for two minutes per wash before adding 60 microliters of an appropriate fluorophore conjugated secondary antibody to each slide for a 40-minute incubation at room temperature.At the end of the incubation, wash the slides in PBS as demonstrated, followed by treatment in 0.3%Sudan black in 70%ethanol to quench any potential formalin-induced autofluorescence. After 30 minutes, wash the slides in tap water to remove any precipitate and immerse the slides in PBS for 10 minutes to prevent any further Sudan black precipitate formation. At the end of the incubation, mount the slides onto confocal glass coverslips with three 60 microliter drops of mounting solution supplemented with DAPI and seal the coverslips with nail polish.Allow the slides to cure for 24 hours at room temperature. Store them at four degrees Celsius protected from light until imaging by confocal laser scanning microscopy according to standard protocols. Be sure to seal the coverslips with nail polish to prevent any movement during imaging and to clean the coverslips of ethanol to enhance the imaging resolution.After imaging 20 glomeruli per slide, open the trainable Weka Segmentation plugin in ImageJ and drop the first image onto the ImageJ toolbar. Click image, color, and split channels. An image showing the primary antibody staining will appear.To create a merged file of the single images, click color and merge channels. A popup box will appear asking for a color to be assigned to each channel. Check the create composite and keep source images boxes and click OK.A merged composite image will appear.Using the primary antibody staining as a guide, draw a region of interest around the glomerular tuft. To perform a Gaussian blur on the single blue DAPI image, click process, filters, and Gaussian blur. Set the blur at one to two.The image will become a little blurry, but the nuclei will appear smooth, the background will be softened. Next, click plugins, segmentation, and trainable Weka Segmentation, and use the free hand tool to trace the intact nuclei. When all of the nuclei of interest have been added, the add class one box, use the line tool to delineate the areas of background to the class two box.Click create new class and use the line tool to outline the DAPI-stained extranuclear DNA. Click train classifier and get probability. Toggle the mouse to obtain a black and white image of all the components with the object of selection highlighted in white.To duplicate this image, click image and duplicate. Under image, adjust and threshold. Use the mouse button to adjust the threshold until only the extracellular DNA is observed.After thresholding, click process, binary, and make binary, and copy the previously generated glomerular region of interest. Press Control Shift E to select edit, selections, and restore to restore the selection. To measure only the extracellular DNA particles within the glomerulus, click analyze particles and OK.A result sheet showing the number of particles, area, average pixels, and percentage of glomeruli containing extracellular DNA will be generated.To save the classifier as an extracellular DNA classifier, click save classifier and save the data. To reapply the model to subsequent images, repeat the initial image processing as demonstrated before selecting load classifier and the saved classifier file. The log menu will pop up and run the model.Once the model has run, click load data and select the extracellularDNA.arff. Then click create result. If the resulting image has failed to pick up all the nuclei, background, or extracellular DNA, click retrain classifier and add more classifiers as necessary.Here, single channel images showing representative DNA and beta actin staining are shown. Merging the two images allows a region of interest to be drawn around the glomerular area for measurement of the extracellular DNA within the mouse kidney glomeruli using trainable Weka Segmentation as demonstrated. This model can be adopted to identify extracellular DNA in kidney biopsy specimens from a control patient or comparison to that of a kidney biopsy from a patient with myeloperoxidase ANCA-associated vasculitis.In addition, this program can be translated to other stains within kidney tissue samples, for example, to stain for neutrophil extracellular traps and the deposition of extracellular myeloperoxidase in ANCA-associated vasculitis. Importantly, no significant differences are observed when the same data is analyzed by multiple users. The most critical step of the analysis is providing enough examples of background, nuclei, and extracellular DNA with glomeruli as classifiers for the Weka Segmentation program to learn from.This method is easily transferrable. For example, further analysis of the different types of cell death can be investigated through staining for specific antibodies against markers for apoptosis or necrosis. Our technique can be used with other inflammatory processes such as assessing TLR expression in autoimmune kidney disease or extracellular myeloperoxidase expression in human kidney biopsies.

supervised-machine-learning-for-semi-quantification-extracellular-dna

Research

JoVE Journal

Immunology and Infection

6.7K visualizações.  Monash University. Glomerulonephritis causa lesão glomerular patológica com considerável morte celular e liberação extracelular de DNA. Este protocolo permite a visualização de DNA extracelular no local da liberação durante a lesão patológica. A vantagem dessa técnica é que ela mede DNA extracelular da morte celular no rim.Ao contrário do soro ou urina, a medição extracelular do DNA é um marcador substituto para danos patológicos. O significado deste método é que tanto a coloração e...