Name: transient expression in red beet of a biopharmaceutical candidate vaccine for type-1 diabetes
Uploaded: 2019-03-19T15:00:00
Description: Watch this Scientific Journal Video about Transient Expression in Red Beet of a Biopharmaceutical Candidate Vaccine for Type-1 Diabetes at JoVE.com

This work was supported by the Joint Project &#8220;The use of plants for the production of an autoimmune diabetes edible vaccine (eDIVA)&#8221; (Project ID: 891854) funded by the University of Verona in the framework of the call 2014.

1. Red beet and spinach cultivation
<ol>
	<li>Grow red beet (B. vulgaris cv Moulin Rouge) and spinach (S. oleracea cv Industria) plants in a growth chamber, using 150 &#181;E of light intensity, 65% relative humidity, 12 h light/dark cycle at 23/21 &#176;C, respectively.</li>
	<li>After seed germination, fertilize the plants twice a week with a 1 g/L solution of a commercially available fertilizer (Table of Materials). For agroinfiltration use five-week-old spinach and six-week-old re...

<ol>
	<li>Merlin, M., Pezzotti, M., Avesani, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Edible+plants+for+oral+delivery+of+biopharmaceuticals.">Edible plants for oral delivery of biopharmaceuticals.</a> British Journal of Clinical Pharmacology. 83 (1), 71-81 (2017).</li><li>Merlin, M., Gecchele, E., Capaldi, S., Pezzotti, M., Avesani, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparative+evaluation+of+recombinant+protein+production+in+different+biofactories:+The+green+perspective.">Comparative evaluation of recombinant protein production in different biofactories: The green perspective.</a> BioMed Research International. , (2014).</li><li>Menkhaus, T. J., Bai, Y., Zhang, C., Nikolov, Z. L., Glatz, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Considerations+for+the+recovery+of+recombinant+proteins+from+plants.">Considerations for the recovery of recombinant proteins from plants.</a> Biotechnology Progress. 20 (4), 1001-1014 (2004).</li><li>Avesani, L., Bortesi, L., Santi, L., Falorni, A., Pezzotti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plant-made+pharmaceuticals+for+the+prevention+and+treatment+of+autoimmune+diseases:+Where+are+we?.">Plant-made pharmaceuticals for the prevention and treatment of autoimmune diseases: Where are we?.</a> Expert Review of Vaccines. 9 (8), 957 (2010).</li><li>Marillonnet, S., Thoeringer, C., Kandzia, R., Klimyuk, V., Gleba, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Systemic+Agrobacterium+tumefaciens-mediated+transfection+of+viral+replicons+for+efficient+transient+expression+in+plants.">Systemic Agrobacterium tumefaciens-mediated transfection of viral replicons for efficient transient expression in plants.</a> Nature Biotechnology. 23, (2005).</li><li>Ludvigsson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Update+on+treatment+of+type+1+diabetes+in+childhood.">Update on treatment of type 1 diabetes in childhood.</a> Current Pediatric Reviews. 1 (2), 118-127 (2013).</li><li>Merlin, 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=Enhanced+GAD65+production+in+plants+using+the+MagnICON+transient+expression+system:+Optimization+of+upstream+production+and+downstream+processing.">Enhanced GAD65 production in plants using the MagnICON transient expression system: Optimization of upstream production and downstream processing.</a> Biotechnology Journal. 11 (4), 542-553 (2016).</li><li>Gecchele, E., Merlin, M., Brozzetti, A., Falorni, A., Pezzotti, M., Avesani, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Comparative+Analysis+of+Recombinant+Protein+Expression+in+Different+Biofactories:+Bacteria,+Insect+Cells+and+Plant+Systems.">A Comparative Analysis of Recombinant Protein Expression in Different Biofactories: Bacteria, Insect Cells and Plant Systems.</a> Journal of Visualized Experiments. 23 (97), (2015).</li><li>Dal Santo, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+terroir+concept+interpreted+through+grape+berry+metabolomics+and+transcriptomics.">The terroir concept interpreted through grape berry metabolomics and transcriptomics.</a> Journal of Visualized Experiments. 5 (116), (2016).</li><li>Chen, Q., 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=Agroinfiltration+as+an+effective+and+scalable+strategy+of+gene+delivery+for+production+of+pharmaceutical+proteins.">Agroinfiltration as an effective and scalable strategy of gene delivery for production of pharmaceutical proteins.</a> Advanced Techniques in Biology and Medicine. 1 (1), (2013).</li><li>Bertini, 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=Design+of+a+type-1+diabetes+vaccine+candidate+using+edible+plants+expressing+a+major+autoantigen.">Design of a type-1 diabetes vaccine candidate using edible plants expressing a major autoantigen.</a> Frontiers in Plant Science. 9, (2018).</li><li>Avesani, L., 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=Improved+in+planta+expression+of+the+human+islet+autoantigen+glutamic+acid+decarboxylase+(GAD65).">Improved in planta expression of the human islet autoantigen glutamic acid decarboxylase (GAD65).</a> Transgenic Research. 12 (2), 203-212 (2003).</li><li>Sep&#250;lveda-Jim&#233;nez, G., Rueda-Ben&#237;tez, P., Porta, H., Rocha-Sosa, 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+red+beet+(Beta+vulgaris)+UDP-glucosyltransferase+gene+induced+by+wounding,+bacterial+infiltration+and+oxidative+stress.">A red beet (Beta vulgaris) UDP-glucosyltransferase gene induced by wounding, bacterial infiltration and oxidative stress.</a> Journal of Experimental Botany. 56, (2005).</li><li>Renukuntla, J., Vadlapudi, A. D., Patel, A., Boddu, S. H. S., Mitra, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Approaches+for+enhancing+oral+bioavailability+of+peptides+and+proteins.">Approaches for enhancing oral bioavailability of peptides and proteins.</a> International Journal of Pharmaceutics. 447, 75-93 (2013).</li><li>. Encapsulation importance in pharmaceutical area, how it is done and issues about herbal extraction Available from: <a target="_blank" href="https://www.researchgate.net/publication/271702091_Encapsulation_importance_in_pharmaceutical_area_how_it_is_done_and_issues_about_herbal_extraction">https://www.researchgate.net/publication/271702091_Encapsulation_importance_in_pharmaceutical_area_how_it_is_done_and_issues_about_herbal_extraction</a> (2015)</li><li>Kamei, N., 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=Complexation+hydrogels+for+intestinal+delivery+of+interferon+beta+and+calcitonin.">Complexation hydrogels for intestinal delivery of interferon beta and calcitonin.</a> Journal of Controlled Release. 134, 98-102 (2009).</li><li>Tuesca, 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=Complexation+hydrogels+for+oral+insulin+delivery:+effects+of+polymer+dosing+on+in+vivo+efficacy.">Complexation hydrogels for oral insulin delivery: effects of polymer dosing on in vivo efficacy.</a> Journal of Pharmaceutical Sciences. 97, 2607-2618 (2008).</li><li>Twyman, R. M., Schillberg, S., Fischer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimizing+the+yield+of+recombinant+pharmaceutical+proteins+in+plants.">Optimizing the yield of recombinant pharmaceutical proteins in plants.</a> Current Pharmaceutical Design. 19, 5486-5494 (2013).</li><li>Dhama, 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=Plant-based+oral+vaccines+for+human+and+animal+pathogens+&#8211;+a+new+era+of+prophylaxis:+current+and+future+perspectives.">Plant-based oral vaccines for human and animal pathogens &#8211; a new era of prophylaxis: current and future perspectives.</a> Journal of Experimental Biology and Agricultural Sciences. 447, 75-93 (2013).</li><li>Hefferon, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconceptualizing+cancer+immunotherapy+based+on+plant+production+systems.">Reconceptualizing cancer immunotherapy based on plant production systems.</a> Future science. O3, (2017).</li></ol>

In this study we showed preliminary analysis for the design of a candidate oral vaccine for autoimmune diabetes. The target protein for this experiment was a mutated form of the human 65 kDa Glutamate Decarboxylase, which production and functionality are easily detectable and measurable12. Its expression in different edible plant tissues was mediated by the vectors5, which mediate a high level of recombinant protein production in a very short time frame. The selection of th...

Since the plant molecular biology revolution in 1980s, plant-based systems for the production of biopharmaceuticals can be considered as an alternative to traditional systems based on microbial and mammalian cells1. Plants display several advantages over traditional platforms, with scalability, cost-effectiveness and safety being the most relevant2. The recombinant product can be purified from transformed plant tissue and then administered, either parenterally or orally and, moreover, transformed edible plant can be used directly for oral delivery. The oral route simultaneously promotes mucosal and systemic immunity, and it eliminates the need for needles and specialized medical personnel. Furthermore, oral delivery eliminates the complex downstream processing, which normally accounts for 80% of the total manufacturing cost of a recombinant protein3. All those advantages can be translated into savings in production, supplies and labor reducing the costs of each dose, making the drug affordable to most of the global population.
Several strategies, both for stable transformation and transient expression, were developed for the production of recombinant proteins in plants. Among them, a high-yield deconstructed plant virus-based expression system (e.g., magnICON) provides superior performance leading high yields of recombinant proteins over relatively short timescales4. Many examples of transient expression using the plant virus-based expression&#160;system in Nicotiana benthamiana plants are reported, being the gold standard production host. However, this model plant is not regarded as an edible species due to the alkaloids and other toxic metabolites that are accumulated in its leaves.
In this work, we describe the comparison between two edible plant systems, red beet (Beta vulgaris cv Moulin Rouge) and spinach (Spinacea oleracea cv Industria), for the expression of two candidate forms of the 65 kDa isoform of glutamic acid decarboxylase (GAD65), carried out by the plant virus-based vectors5. GAD65 is a major autoantigen associated to Type 1 Diabetes (T1D) and it is currently under investigation in human clinical trials to prevent or delay T1D by inducing tolerance6. The production of GAD65 in plants has been extensively studied in model plant species as Nicotiana tabacum and N. benthamiana4,5,6,7. Here, we describe the use of edible plant species for the production of the molecule in tissues that can be meant for a direct oral delivery. From a technical point of view, we studied and selected the system for plant agroinfiltration and the edible plant platform for GAD65 production by evaluating different parameters: the recombinant protein expression levels, the residual microbial charge in plant tissue meant for oral delivery, the resistance of GAD65 to the gastric digestion, and the bioequivalence of the transformed plants with the wild type.

<table>
	<tbody>
		<tr>
			<td>0.2-&#956;m Minisart RC4 membrane filters</td>
			<td>Sartorius-Stedim</td>
			<td>17764</td>
			<td></td>
		</tr>
		<tr>
			<td>2&#8211;mercaptoethanol</td>
			<td>Sigma</td>
			<td>M3148</td>
			<td>Toxic; 4 % to make loading buffer with glycerol, SDS and Tris-HCl</td>
		</tr>
		<tr>
			<td>4-Morpholineethanesulfonic acid (MES)</td>
			<td>Sigma</td>
			<td>M8250</td>
			<td>pH 5.5</td>
		</tr>
		<tr>
			<td>96-well plate</td>
			<td>Sarstedt</td>
			<td>833924</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic acid</td>
			<td>Sigma</td>
			<td>27221</td>
			<td>Corrosive</td>
		</tr>
		<tr>
			<td>Acetonitrile LC-MS grade</td>
			<td>Sigma</td>
			<td>34967</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetosyringone</td>
			<td>Sigma</td>
			<td>D134406</td>
			<td>Toxic &#8211; 0.1 M stock in DMSO</td>
		</tr>
		<tr>
			<td>Agar Bacteriological Grade</td>
			<td>Applichem</td>
			<td>A0949</td>
			<td>15 g/L to make LB medium (pH 7.5 with NaOH) with Yeast extract, NaCl and Tryptone</td>
		</tr>
		<tr>
			<td>Ammonium formate</td>
			<td>Sigma</td>
			<td>70221</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-eGFP antibody</td>
			<td>ABCam</td>
			<td>ab290</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-GAD 65/67 antibody</td>
			<td>Sigma</td>
			<td>G5163</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-LHCB2 antibody</td>
			<td>Agrisera</td>
			<td>AS01 003</td>
			<td></td>
		</tr>
		<tr>
			<td>Brilliant Blue R-250</td>
			<td>Sigma</td>
			<td>B7920</td>
			<td></td>
		</tr>
		<tr>
			<td>C18 Column</td>
			<td>Grace</td>
			<td>&#160;&#160; -</td>
			<td>Alltima HP C18 (150 mm x 2.1 mm; 3 &#956;m) Column</td>
		</tr>
		<tr>
			<td>C18 Guard Column</td>
			<td>Grace</td>
			<td>&#160;&#160; -</td>
			<td>Alltima HP C18 (7.5 mm x 2.1 mm; 5 &#956;m) Guard&#160; Column</td>
		</tr>
		<tr>
			<td>CalMag Grower</td>
			<td>Peter Excel</td>
			<td>15-5-15</td>
			<td>Fertilizer</td>
		</tr>
		<tr>
			<td>Carbenicillin disodium</td>
			<td>Duchefa Biochemie</td>
			<td>C0109</td>
			<td>Toxic</td>
		</tr>
		<tr>
			<td>Chemiluminescence imaging system</td>
			<td>BioRad</td>
			<td>1708370</td>
			<td>ChemiDoc Touch Imaging System</td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Sigma</td>
			<td>C2432</td>
			<td></td>
		</tr>
		<tr>
			<td>Detergent</td>
			<td>Sigma</td>
			<td>P5927</td>
			<td>Polysorbate 20</td>
		</tr>
		<tr>
			<td>Fluorescence reader</td>
			<td>Perkin-Elmer</td>
			<td>&#160;1420-011</td>
			<td>VICTOR Multilabel Counter</td>
		</tr>
		<tr>
			<td>Formic acid LC-MS grade</td>
			<td>Sigma</td>
			<td>94318</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sigma</td>
			<td>G5516</td>
			<td>15 % to make loading buffer with Tris-HCl, SDS and 2&#8211;mercaptoethanol</td>
		</tr>
		<tr>
			<td>GoTaq G2 polymerase</td>
			<td>Promega</td>
			<td>M7841</td>
			<td></td>
		</tr>
		<tr>
			<td>HCl</td>
			<td>Sigma</td>
			<td>H1758</td>
			<td>Corrosive</td>
		</tr>
		<tr>
			<td>HILIC Column</td>
			<td>Grace</td>
			<td>&#160;&#160; -</td>
			<td>Ascentis Express HILIC (150 mm x 2.1 mm; particles size 2.7 &#956;m) Column</td>
		</tr>
		<tr>
			<td>HILIC Guard Column</td>
			<td>Grace</td>
			<td>&#160;&#160; -</td>
			<td>Vision HT HILIC (7.5 mm x 2.1 mm; 3 &#956;m) Guard&#160; Column</td>
		</tr>
		<tr>
			<td>Horseradish peroxidase (HRP)-conjugate anti-rabbit antibody</td>
			<td>Sigma</td>
			<td>A6154</td>
			<td>Do not freeze/thaw too many times</td>
		</tr>
		<tr>
			<td>HPLC Autosampler</td>
			<td>Beckman Coulter</td>
			<td>&#160;&#160; -</td>
			<td>System Gold 508 Autosampler</td>
		</tr>
		<tr>
			<td>HPLC System</td>
			<td>Beckman Coulter</td>
			<td>&#160;&#160; -</td>
			<td>System Gold 128 Solvent Module HPLC</td>
		</tr>
		<tr>
			<td>Isopropanol</td>
			<td>Sigma</td>
			<td>24137</td>
			<td>Flamable</td>
		</tr>
		<tr>
			<td>Kanamycin sulfate</td>
			<td>Sigma</td>
			<td>K4000</td>
			<td>Toxic</td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma</td>
			<td>P9541</td>
			<td>2 g/L with NaCl , Na2HPO4 and KH2PO4 to make PBS</td>
		</tr>
		<tr>
			<td>KH2PO4</td>
			<td>Sigma</td>
			<td>P9791</td>
			<td>2.4 g/L with NaCl , Na2HPO4 and KCl to make PBS</td>
		</tr>
		<tr>
			<td>Loading Buffer</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Luminol solution</td>
			<td>Ge Healthcare</td>
			<td>RPN2232</td>
			<td>Prepare the solution using the ECL Prime Western Blotting System commercial kit</td>
		</tr>
		<tr>
			<td>Lyophilizator</td>
			<td>5Pascal</td>
			<td>LIO5P0000DGT</td>
			<td></td>
		</tr>
		<tr>
			<td>Mass Spectometer</td>
			<td>Bruker Daltonics</td>
			<td>&#160; -</td>
			<td>Bruker Esquire 6000; the mass spectrometer was equipped with an ESI source and the analyzer was an ion trap</td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Sigma</td>
			<td>32213</td>
			<td></td>
		</tr>
		<tr>
			<td>MgSO4</td>
			<td>Sigma</td>
			<td>M7506</td>
			<td></td>
		</tr>
		<tr>
			<td>Milk-blocking solution</td>
			<td>Ristora</td>
			<td>&#160;&#160; -</td>
			<td>3 % in PBS</td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>Sigma</td>
			<td>S7907</td>
			<td>Use with NaH2PO4 to make Sodium Phospate buffer</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma</td>
			<td>S3014</td>
			<td>80 g/L with KCl, Na2HPO4 and KH2PO4 to make PBS; 10 g/L to make LB medium (pH 7.5 with NaOH) with Yeast extract, Tryptone and Agar Bacteriological Grade</td>
		</tr>
		<tr>
			<td>NaH2PO4</td>
			<td>Sigma</td>
			<td>S8282</td>
			<td>&#160;Use with Na2HPO4 to make Sodium Phospate buffer; 14.4 g/L to make PBS</td>
		</tr>
		<tr>
			<td>NaOH</td>
			<td>Sigma</td>
			<td>S8045</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrocellulase membrane</td>
			<td>Ge Healthcare</td>
			<td>10600002</td>
			<td></td>
		</tr>
		<tr>
			<td>Pepsin from porcine gastric mucosa</td>
			<td>Sigma</td>
			<td>P7000</td>
			<td></td>
		</tr>
		<tr>
			<td>Peroxidase substrate ECL</td>
			<td>GE Healthcare</td>
			<td>RPN2235</td>
			<td>Light sensitive material</td>
		</tr>
		<tr>
			<td>Pump Vacuum Press</td>
			<td>VWR</td>
			<td>111400000098</td>
			<td></td>
		</tr>
		<tr>
			<td>Reagent A</td>
			<td>Sigma</td>
			<td>B9643</td>
			<td>Use 50 parts of this reagent with 1 part of reagent B to prepare BCA working solution</td>
		</tr>
		<tr>
			<td>Reagent B</td>
			<td>Sigma</td>
			<td>B9643</td>
			<td>Use 1 part of this reagent with 50 parts of reagent A to prepare BCA working solution</td>
		</tr>
		<tr>
			<td>Rifampicin</td>
			<td>Duchefa Biochemie</td>
			<td>R0146</td>
			<td>Toxic &#8211; 25 mg/mL stock in DMSO</td>
		</tr>
		<tr>
			<td>SDS (Sodium dodecyl sulphate)</td>
			<td>Sigma</td>
			<td>L3771</td>
			<td>Flamable, toxic, corrosive-10 % stock; 3 % to make loading buffer with Tris-HCl, Glycerol and 2&#8211;mercaptoethanol</td>
		</tr>
		<tr>
			<td>Sodium metabisulphite</td>
			<td>Sigma</td>
			<td>7681-57-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Sonicator system</td>
			<td>Soltec</td>
			<td>090.003.0003</td>
			<td>Sonica&#174; 2200 MH; frequency 40 khz</td>
		</tr>
		<tr>
			<td>Syringe</td>
			<td>Terumo</td>
			<td>&#160;&#160; -</td>
			<td></td>
		</tr>
		<tr>
			<td>Transparent fixed 300-&#181;L insert glass tubes</td>
			<td>Thermo Scientific</td>
			<td>11573680</td>
			<td></td>
		</tr>
		<tr>
			<td>Trizma Base</td>
			<td>Sigma</td>
			<td>T1503</td>
			<td>Adjust pH with 1N HCl to make Tris-HCl buffer, use 1,5M Tris-HCl (pH 6.8) to make loading buffer with SDS, Glycerol and 2&#8211;mercaptoethanol</td>
		</tr>
		<tr>
			<td>Tryptone</td>
			<td>Formedium</td>
			<td>TRP03</td>
			<td>10 g/L to make LB medium (pH 7.5 with NaOH) with Yeast extract, NaCl and Agar Bacteriological Grade</td>
		</tr>
		<tr>
			<td>Vacuum concentrator</td>
			<td>Heto</td>
			<td>3878 F1-3</td>
			<td>Speed-vac System</td>
		</tr>
		<tr>
			<td>Water LC-MS grade</td>
			<td>Sigma</td>
			<td>39253</td>
			<td></td>
		</tr>
		<tr>
			<td>Yeast extract</td>
			<td>Sigma</td>
			<td>Y1333</td>
			<td>5 g/L to make LB medium (pH 7.5 with NaOH) with Tryptone, NaCl and Agar Bacteriological Grade</td>
		</tr>
	</tbody>
</table>

transient expression in red beet of a biopharmaceutical candidate vaccine for type-1 diabetes

Plant molecular farming is the use of plants to produce molecules of interest. In this perspective, plants may be used both as bioreactors for the production and subsequent purification of the final product and for the direct oral delivery of heterologous proteins when using edible plant species. In this work, we present the development of a candidate oral vaccine against Type 1 Diabetes (T1D) in edible plant systems using deconstructed plant virus-based recombinant DNA technology, delivered with vacuum infiltration. Our results show that a red beet is a suitable host for the transient expression of a human derived autoantigen associated to T1D, considered to be a promising candidate as a T1D vaccine. Leaves producing the autoantigen were thoroughly characterized for their resistance to gastric digestion, for the presence of residual bacterial charge and for their secondary metabolic profile, giving an overview of the process production for the potential use of plants for direct oral delivery of a heterologous protein. Our analysis showed almost complete degradation of the freeze-dried candidate oral vaccine following a simulated gastric digestion, suggesting that an encapsulation strategy in the manufacture of the plant-derived GAD vaccine is required.

In this work, the workflow for the development of an oral vaccine in edible plant tissues is presented. The focus of this work is the expression of a target protein in an edible host plant species and the characterization of the potential oral vaccine.
The first step involved the evaluation of the suitability of the plant virus-based expression technology to produce recombinant proteins in edible plant systems. For this aim, we ...

Watch this Scientific Journal Video about Transient Expression in Red Beet of a Biopharmaceutical Candidate Vaccine for Type-1 Diabetes at JoVE.com

Transient Expression in Red Beet of a Biopharmaceutical Candidate Vaccine for Type-1 Diabetes

Here, we present a protocol to produce an oral vaccine candidate against Type 1 diabetes in an edible plant.

Plant molecular farming is the use of plants to produce molecules of interest. In this perspective, plants may be used both as bioreactors for the ...

Among the different strategies for production of recombinant protein in plants, the deconstructed plant-based VERS expression provides superior performance, leading to high yields over a relative short time frame. Replication of this technology for the production of an oral vaccine holds a great potential to become an alternative to conventional vaccines in the near future. Lyophilized red beet leaves transiently transformed accumulates an amount of photo antigens suitable for oral tolerance induction in type one diabetes prevention.This experimental protocol could be extended to many different edible species after a case-by-case evaluation of recombinant protein accumulation. Demonstrating the procedure will be Edoardo Bertini, Mattia Santoni, Anna Cuccurullo, and Roberta Zampieri. To begin this procedure, grow red beet and spinach plants in a growth chamber as outlined in the text protocol.After seed germination, fertilize the plants twice a week with a solution of commercially available fertilizer at a concentration of one gram per liter. For agroinfiltration, use five week old spinach and six week old red beet plants. After constructing the plant expression vectors, inoculate the three A.tumefaciens transformants in 50 milliliters of LB medium containing rifampicin at a concentration of 50 micrograms per milliliter and vector-specific antibiotics as outlined in the text protocol.Grow by shaking overnight at 28 degrees Celsius. The next day, pellet the bacterial cultures by centrifuging at 4500 times G for 20 minutes. Resuspend the pellet in 100 milliliters of infiltration buffer containing 10 millimolar MES and 10 millimolar magnesium sulfate.Incubate the suspensions at room temperature for three hours. Mix an equal volume of a bacterial suspension containing one of the modules shown here, with the five prime module and the integrase module. Using a syringe without a needle, take out five milliliters of the suspension mix.Press the tip of the syringe against the underside of the plant leaf while applying gently counter pressure to the other side of the leaf. Infiltrate the first three completely expanded leaves, starting from the apex, for each plant. Label the agroinfiltrated leaves with the paper tag on the leaf stem.Then return the plants to the growth chamber under standard conditions. On days four to 14 post-infection, collect the agroinfiltrated leaves and freeze them in liquid nitrogen. Store this plant tissue at minus 80 degrees Celsius.First, separately grow the three A.tumefaciens transformants in 50 milliliters of LB medium containing rifampicin at a concentration of 50 microliters per milliliter, and appropriate vector-specific antibiotics by shaking overnight at 28 degrees Celsius. The next day, pellet the bacterial cultures by centrifuging at 4500 times G for 20 minutes. Resuspend the pellet in 1 liter of infiltration buffer to an OD600 of 0.35, and incubate the suspensions at room temperature for three hours.Then add 0.01%of the detergent to each suspension. Mix an equal volume of a bacterial suspension containing one of the modules shown here with the five prime module and the integrase module. Insert one six week old red beet plant into the holder.Invert the holder and place it on top of a beaker containing two liters of an infiltration bath to submerge the leaves in the infiltration suspension. After this, transfer the infiltration bath with the submerged plant to the infiltration chamber and close it. Turn on the vacuum pump and open the vacuum intake valve on the infiltration chamber.Once the pressure in the chamber has fallen to 90 millibar, maintain the vacuum for three minutes. Then release the vacuum for 45 seconds. When the chamber has returned to atmospheric pressure, open the chamber and remove the infiltrated plant from the bacterial bath.Return the plant to the growth chamber. On the day of maximum expression, harvest the infiltrated leaves and freeze them in liquid nitrogen as previously described. First, harvest the vacuum agroinfiltrated delta 87 GAD65mut expressing red beet leaves at the expression peak, and freeze them in liquid nitrogen.Lyophilize the frozen leaves at minus 50 degrees Celsius and at 0.04 millibar for 72 hours. Then store them at minus 80 degrees Celsius. When ready to proceed, grind the leaves to a fine powder and store at room temperature in a sealed container with silica gel to exclude the moisture.For the gastric digestion simulation, weigh 100 milligrams of the finely ground freeze dried red beet leaves, and resuspend it in six milliliters of PBS. Use six molar hydrochloric acid to adjust the sample pH to two. Add four milligrams per milliliters pepsin from porcine gastric mucosa, and 10 millimolar hydrochloric acid, to obtain a final pepsin concentration of one milligram per milliliter.Shake the sample at 37 degrees Celsius for 120 minutes. Next, use sodium hydroxide to adjust the sample pH to eight and inactivate the pepsin. Transfer 750 microliter aliquots of each sample to microcentrifuge tubes, and centrifuge the aliquots at 20, 000 times G and at four degrees Celsius for 20 minutes.Collect each supernatant separately, and resuspend each pellet in one supernatant volume of loading buffer. Then analyze both the supernatant and the resuspended pellet by Western blot analysis. For the cell integrity analysis, prepare two samples of 100 milligrams of the finely ground freeze-dried red beet leaves, and resuspend both in six milliliters of PBS.Use six molar hydrochloric acid to adjust the pH of one sample to two. Shake both samples at 37 degrees Celsius for 120 minutes. Then aliquot 750 microliters of each sample to microcentrifuge tubes.Centrifuge at 20, 000 times G and at 4 degrees Celsius for 20 minutes. Collect each supernatant separately, and resuspend each pellet in one supernatant volume of loading buffer. Then analyze both the supernatant and the resuspended pellet by Western blot analysis.First, weigh 100 milligrams of the finely ground freeze-dried red beet leaves, and resuspend it in eight milliliters of sterile PBS. Vortex for one minute. Plate one milliliter of each freeze-dried leaf homogenate in one of the five prepared selective LB media.Incubate the plates at 28 degrees Celsius for three days. After this, count the agrobacterium colonies grown on each plate, and calculate the residual bacterial charge as the number of colony forming units per milliliter of the freeze-dried leaf homogenate. In this work, an oral vaccine is developed in edible plant tissue.Red beet and spinach plants are manually agroinfiltrated with suspensions of A.tumefaciens carrying EGFP recombinant expression vectors, and the fluorescent protein expression is visualized by Western blot analysis and quantified under UV light. The red beet system is characterized by a higher EGFP expression, reaching approximately 544 micrograms per gram of fresh leaf weight at nine days post-infection, while the spinach only reached a maximum level of approximately 113.4 micrograms per gram of fresh leaf weight on 11 days post-infection. Because of this, the red beet is selected as the expression host for all subsequent experiments.Plants are then vacuum infiltrated with an A.tumefaciens suspension. After the TSP extraction from agroinfiltration leaves, the samples are analyzed by Western blot, and the recombinant protein is relatively quantified by a densitometry analysis. Finally, the parameters for the development of a potential oral vaccine are evaluated.As seen here, the target protein is seen to be stable after the lyophilization process. Gastric digestion is simulated by adding the porcine gastric enzyme pepsin to freeze-dried material, either to a final concentration of one milligram per milliliter, or a ratio of one to 20, to TSP. Both digestive treatment conditions result in degradation of the recombinant protein.The absence of a specific signal in the pellet samples after pepsin digestion suggest that after freeze-drying, the plant cells lost their integrity, and this led to the target protein degradation. The procedure should be carefully adapted to the plant species in respect to vacuum infiltration and to the target recombinant protein in respect to time course analysis. The demonstrating procedure might also be used for the production of biopharmaceutical intended for oral delivery, like vaccine and antibodies.

transient-expression-red-beet-biopharmaceutical-candidate-vaccine-for

Research

JoVE Journal

Bioengineering

Creating Two-Dimensional Patterned Substrates for Protein and Cell Confinement

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1 While microcontact printing can be employed to directly print a large number of molecules, including proteins,2 DNA,3 and silanes,4 the formation of self-assembled monolayers (SAMs) from long chain alkane thiols on gold provides a simple way to confine proteins and cells to specific patterns containing adhesive and resistant regions. This confinement can be used to control cell morphology and is useful for examining a variety of questions in protein and cell biology. Here, we describe a general method for the creation of well-defined protein patterns for cellular studies.5 This process involves three steps: the production of a patterned master using photolithography, the creation of a PDMS stamp, and microcontact printing of a gold-coated substrate. Once patterned, these cell culture substrates are capable of confining proteins and/or cells (primary cells or cell lines) to the pattern.
The use of self-assembled monolayer chemistry allows for precise control over the patterned protein/cell adhesive regions and non-adhesive regions; this cannot be achieved using direct protein stamping. Hexadecanethiol, the long chain alkane thiol used in the microcontact printing step, produces a hydrophobic surface that readily adsorbs protein from solution. The glycol-terminated thiol, used for backfilling the non-printed regions of the substrate, creates a monolayer that is resistant to protein adsorption and therefore cell growth.6 These thiol monomers produce highly structured monolayers that precisely define regions of the substrate that can support protein adsorption and cell growth. As a result, these substrates are useful for a wide variety of applications from the study of intercellular behavior7 to the creation of microelectronics.8
While other types of monolayer chemistry have been used for cell culture studies, including work from our group using trichlorosilanes to create patterns directly on glass substrates,9 patterned monolayers formed from alkane thiols on gold are straight-forward to prepare. Moreover, the monomers used for monolayer preparation are commercially available, stable, and do not require storage or handling under inert atmosphere. Patterned substrates prepared from alkane thiols can also be recycled and reused several times, maintaining cell confinement.10

Self-assembled monolayers (SAMs) formed from long chain alkane thiols on gold provide well-defined substrates for the formation of protein patterns and cell confinement. Microcontact printing of hexadecanethiol using a polydimethylsiloxane (PDMS) stamp followed by backfilling with a glycol-terminated alkane thiol monomer produces a pattern where protein and cells adsorb only to the stamped hexadecanethiol region.

Microcontact printing provides a rapid, highly reproducible method for the creation of well-defined patterned substrates.1  While microcontact printing ...

Creating Transient Cell Membrane Pores Using a Standard Inkjet Printer

Bioprinting has a wide range of applications and significance, including tissue engineering, direct cell application therapies, and biosensor microfabrication.1-10 Recently, thermal inkjet printing has also been used for gene transfection.8,9 The thermal inkjet printing process was shown to temporarily disrupt the cell membranes without affecting cell viability. The transient pores in the membrane can be used to introduce molecules, which would otherwise be too large to pass through the membrane, into the cell cytoplasm.8,9,11
The application being demonstrated here is the use of thermal inkjet printing for the incorporation of fluorescently labeled g-actin monomers into cells. The advantage of using thermal ink-jet printing to inject molecules into cells is that the technique is relatively benign to cells.8, 12 Cell viability after printing has been shown to be similar to standard cell plating methods1,8. In addition, inkjet printing can process thousands of cells in minutes, which is much faster than manual microinjection. The pores created by printing have been shown to close within about two hours. However, there is a limit to the size of the pore created (~10 nm) with this printing technique, which limits the technique to injecting cells with small proteins and/or particles. 8,9,11
A standard HP DeskJet 500 printer was modified to allow for cell printing.3, 5, 8 The cover of the printer was removed and the paper feed mechanism was bypassed using a mechanical lever. A stage was created to allow for placement of microscope slides and coverslips directly under the print head. Ink cartridges were opened, the ink was removed and they were cleaned prior to use with cells. The printing pattern was created using standard drawing software, which then controlled the printer through a simple print command. 3T3 fibroblasts were grown to confluence, trypsinized, and then resuspended into phosphate buffered saline with soluble fluorescently labeled g-actin monomers. The cell suspension was pipetted into the ink cartridge and lines of cells were printed onto glass microscope cover slips. The live cells were imaged using fluorescence microscopy and actin was found throughout the cytoplasm. Incorporation of fluorescent actin into the cell allows for imaging of short-time cytoskeletal dynamics and is useful for a wide range of applications.13-15

A description of the methods used to convert an HP DeskJet 500 printer into a bioprinter. The printer is capable of processing living cells, which causes transient pores in the membrane. These pores can be utilized to incorporate small molecules, including fluorescent G-actin, into the printed cells.

Bioprinting has a wide range of applications and significance, including tissue engineering, direct cell application therapies, and biosensor ...

Skin Tattooing As A Novel Approach For DNA Vaccine Delivery

Nucleic acid-based vaccination is a topic of growing interest, especially plasmid DNA (pDNA) encoding immunologically important antigens. After the engineered pDNA is administered to the vaccines, it is transcribed and translated into immunogen proteins that can elicit responses from the immune system. Many ways of delivering DNA vaccines have been investigated; however each delivery route has its own advantages and pitfalls. Skin tattooing is a novel technique that is safe, cost-effective, and convenient. In addition, the punctures inflicted by the needle could also serve as a potent adjuvant. Here, we a) demonstrate the intradermal delivery of plasmid DNA encoding enhanced green fluorescent protein (pCX-EGFP) in a mouse model using a tattooing device and b) confirm the effective expression of EGFP in the skin cells using confocal microscopy.

Skin tattooing is a potent and safe way to delivery DNA vaccine intradermally. Here, a DNA plasmid encoding EGFP is delivered by tattooing to the skin of a laboratory mouse, and the expression of EGFP in the skin cells is then inspected by confocal microscopy.

Nucleic acid-based vaccination is a topic of growing interest, especially plasmid DNA (pDNA) encoding immunologically important antigens. After the ...

Characterization of Complex Systems Using the Design of Experiments Approach: Transient Protein Expression in Tobacco as a Case Study

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the additional advantage of short development and production times, but expression levels can vary significantly between batches thus giving rise to regulatory concerns in the context of good manufacturing practice. We used a design of experiments (DoE) approach to determine the impact of major factors such as regulatory elements in the expression construct, plant growth and development parameters, and the incubation conditions during expression, on the variability of expression between batches. We tested plants expressing a model anti-HIV monoclonal antibody (2G12) and a fluorescent marker protein (DsRed). We discuss the rationale for selecting certain properties of the model and identify its potential limitations. The general approach can easily be transferred to other problems because the principles of the model are broadly applicable: knowledge-based parameter selection, complexity reduction by splitting the initial problem into smaller modules, software-guided setup of optimal experiment combinations and step-wise design augmentation. Therefore, the methodology is not only useful for characterizing protein expression in plants but also for the investigation of other complex systems lacking a mechanistic description. The predictive equations describing the interconnectivity between parameters can be used to establish mechanistic models for other complex systems.

We describe a design of experiments approach that can be used to determine and model the influence of transgene regulatory elements, plant growth and development parameters, and incubation conditions on the transient expression of monoclonal antibodies and reporter proteins in plants.

Plants provide multiple benefits for the production of biopharmaceuticals including low costs, scalability, and safety. Transient expression offers the ...

Fabrication of a Functionalized Magnetic Bacterial Nanocellulose with Iron Oxide Nanoparticles

In this study, bacterial nanocellulose (BNC) produced by the bacteria Gluconacetobacter xylinus is synthesized and impregnated in situ with iron oxide nanoparticles (IONP) (Fe3O4) to yield a magnetic bacterial nanocellulose (MBNC). The synthesis of MBNC is a precise and specifically designed multi-step process. Briefly, bacterial nanocellulose (BNC) pellicles are formed from preserved G. xylinus strain according to our experimental requirements of size and morphology. A solution of iron(III) chloride hexahydrate (FeCl3&#183;6H2O) and iron(II) chloride tetrahydrate (FeCl2&#183;4H2O) with a 2:1 molar ratio is prepared and diluted in deoxygenated high purity water. A BNC pellicle is then introduced in the vessel with the reactants. This mixture is stirred and heated at 80 &#176;C in a silicon oil bath and ammonium hydroxide (14%) is then added by dropping to precipitate the ferrous ions into the BNC mesh. This last step allows forming in situ magnetite nanoparticles (Fe3O4) inside the bacterial nanocellulose mesh to confer magnetic properties to BNC pellicle. A toxicological assay was used to evaluate the biocompatibility of the BNC-IONP pellicle. Polyethylene glycol (PEG) was used to cover the IONPs in order to improve their biocompatibility. Scanning electron microscopy (SEM) images showed that the IONP were located preferentially in the fibril interlacing spaces of the BNC matrix, but some of them were also found along the BNC ribbons. Magnetic force microscope measurements performed on the MBNC detected the presence magnetic domains with high and weak intensity magnetic field, confirming the magnetic nature of the MBNC pellicle. Young&#39;s modulus values obtained in this work are also in a reasonable agreement with those reported for several blood vessels in previous studies.

Here, we present a protocol to make a bacterial nanocellulose (BNC) magnetic for applications in damaged blood vessel reconstruction. The BNC was synthesized by G. xylinus strain. On the other hand, magnetization of the BNC was realized through in situ precipitation of Fe2+ and Fe3+ ferrous ions inside the BNC mesh.

In this study, bacterial nanocellulose (BNC) produced by the bacteria Gluconacetobacter xylinus is synthesized and impregnated in situ with iron oxide ...

Microfluidic Flow Chambers Using Reconstituted Blood to Model Hemostasis and Platelet Transfusion In Vitro

Blood platelets prepared for transfusion gradually lose hemostatic function during storage. Platelet function can be investigated using a variety of (indirect) in vitro experiments, but none of these is as comprehensive as microfluidic flow chambers. In this protocol, the reconstitution of thrombocytopenic fresh blood with stored blood bank platelets is used to simulate platelet transfusion. Next, the reconstituted sample is perfused in microfluidic flow chambers which mimic hemostasis on exposed subendothelial matrix proteins. Effects of blood donation, transport, component separation, storage and pathogen inactivation can be measured in paired experimental designs. This allows reliable comparison of the impact every manipulation in blood component preparation has on hemostasis. Our results demonstrate the impact of temperature cycling, shear rates, platelet concentration and storage duration on platelet function. In conclusion, this protocol analyzes the function of blood bank platelets and this ultimately aids in optimization of the processing chain including phlebotomy, transport, component preparation, storage and transfusion.

Microfluidic Flow Chambers Using Reconstituted Blood to Model Hemostasis and Platelet Transfusion In Vitro

Platelet transfusion and hemostasis was modeled using blood reconstitution and microfluidic flow chambers to investigate the function of blood banking platelets. The data demonstrate the consequences of platelet storage lesion on hemostasis, in vitro.

Blood platelets prepared for transfusion gradually lose hemostatic function during storage. Platelet function can be investigated using a variety of ...

Development of a Multicellular Three-dimensional Organotypic Model of the Human Intestinal Mucosa Grown Under Microgravity

Because cells growing in a three-dimensional (3-D) environment have the potential to bridge many gaps of cell cultivation in 2-D environments (e.g., flasks or dishes). In fact, it is widely recognized that cells grown in flasks or dishes tend to de-differentiate and lose specialized features of the tissues from which they were derived. Currently, there are mainly two types of 3-D culture systems where the cells are seeded into scaffolds mimicking the native extracellular matrix (ECM): (a) static models and (b) models using bioreactors. The first breakthrough was the static 3-D models. 3-D models using bioreactors such as the rotating-wall-vessel (RWV) bioreactors are a more recent development. The original concept of the RWV bioreactors was developed at NASA&#39;s Johnson Space Center in the early 1990s and is believed to overcome the limitations of static models such as the development of hypoxic, necrotic cores. The RWV bioreactors might circumvent this problem by providing fluid dynamics that allow the efficient diffusion of nutrients and oxygen. These bioreactors consist of a rotator base that serves to support and rotate two different formats of culture vessels that differ by their aeration source type: (1) Slow Turning Lateral Vessels (STLVs) with a co-axial oxygenator in the center, or (2) High Aspect Ratio Vessels (HARVs) with oxygenation via a flat, silicone rubber gas transfer membrane. These vessels allow efficient gas transfer while avoiding bubble formation and consequent turbulence. These conditions result in laminar flow and minimal shear force that models reduced gravity (microgravity) inside the culture vessel. Here we describe the development of a multicellular 3-D organotypic model of the human intestinal mucosa composed of an intestinal epithelial cell line and primary human lymphocytes, endothelial cells and fibroblasts cultured under microgravity provided by the RWV bioreactor.

Cells growing in a three-dimensional (3-D) environment represent a marked improvement over cell cultivation in 2-D environments (e.g., flasks or dishes). Here we describe the development of a multicellular 3-D organotypic model of the human intestinal mucosa cultured under microgravity provided by rotating-wall-vessel (RWV) bioreactors.

Because cells growing in a three-dimensional (3-D) environment have the potential to bridge many gaps of cell cultivation in 2-D environments (e.g., ...

A Microfluidic Flow Chamber Model for Platelet Transfusion and Hemostasis Measures Platelet Deposition and Fibrin Formation in Real-time

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is restricted to platelet deposition only. The intricate relationship between Ca2+-dependent coagulation and platelet function requires careful and controlled recalcification of blood prior to analysis. Our setup uses a Y-shaped mixing channel, which supplies concentrated Ca2+/Mg2+ buffer to flowing blood just prior to perfusion, enabling rapid recalcification without sample stasis. A ten-fold difference in flow velocity between both reservoirs minimizes dilution. The recalcified blood is then perfused in a collagen-coated analysis chamber, and differential labeling permits real-time imaging of both platelet and fibrin deposition using fluorescence video microscopy. The system uses only commercially available tools, increasing the chances of standardization. Reconstitution of thrombocytopenic blood with platelets from banked concentrates furthermore models platelet transfusion, proving its use in this research domain. Exemplary data demonstrated that coagulation onset and fibrin deposition were linearly dependent on the platelet concentration, confirming the relationship between primary and secondary hemostasis in our model. In a timeframe of 16 perfusion min, contact activation did not take place, despite recalcification to normal Ca2+ and Mg2+ levels. When coagulation factor XIIa was inhibited by corn trypsin inhibitor, this time frame was even longer, indicating a considerable dynamic range in which the changes in the procoagulant nature of the platelets can be assessed. Co-immobilization of tissue factor with collagen significantly reduced the time to onset of coagulation, but not its rate. The option to study the tissue factor and/or the contact pathway increases the versatility and utility of the assay.

This paper describes an experimental model of hemostasis that simultaneously measures platelet function and coagulation. Platelet and fibrin fluorescence is measured in real-time, and platelet adhesion rate, coagulation rate, and onset of coagulation are determined. The model is used to determine platelet procoagulant properties under flow in concentrates for transfusion.

Microfluidic models of hemostasis assess platelet function under conditions of hydrodynamic shear, but in the presence of anticoagulants, this analysis is ...

Gene Expression Analysis of Endothelial Cells Exposed to Shear Stress Using Multiple Parallel-plate Flow Chambers

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate flow chambers. Endothelial cells form the inner cellular lining of blood vessels and are chronically exposed to the frictional force of blood flow called shear stress. Under physiological conditions, endothelial cells function in the presence of various shear stress conditions. Thus, the application of shear stress conditions in in vitro models can provide greater insight into endothelial responses in vivo. The parallel-plate flow chamber previously published by Lane et al.9 is adapted to study endothelial gene regulation in the presence and absence of steady (non-pulsatile) laminar flow. Key adaptations in the set-up for laminar flow as presented here include a large, dedicated environment to house concurrent flow circuits, the monitoring of flow rates in real-time, and the inclusion of an exogenous reference RNA for the normalization of quantitative real-time PCR data. To assess multiple treatments/conditions with the application of shear stress, multiple flow circuits and pumps are used simultaneously within the same heated and humidified incubator. The flow rate of each flow circuit is measured continuously in real-time to standardize shear stress conditions throughout the experiments. Because these experiments have multiple conditions, we also use an exogenous reference RNA that is spiked-in at the time of RNA extraction for the normalization of RNA extraction and first-strand cDNA synthesis efficiencies. These steps minimize the variability between samples. This strategy is employed in our pipeline for the gene expression analysis with shear stress experiments using the parallel-plate flow chamber, but parts of this strategy, such as the exogenous reference RNA spike-in, can easily and cost-effectively be used for other applications.

Here, a workflow for the culture and gene expression analysis of endothelial cells under fluid shear stress is presented. Included is a physical arrangement for simultaneously housing and monitoring multiple flow chambers in a controlled environment and the use of an exogenous reference RNA for quantitative PCR.

We describe a workflow for the analysis of gene expression from endothelial cells subject to a steady laminar flow using multiple monitored parallel-plate ...

A Multilayer Microfluidic Platform for the Conduction of Prolonged Cell-Free Gene Expression

The limitations of cell-based synthetic biology are becoming increasingly apparent as researchers aim to develop larger and more complex synthetic genetic regulatory circuits. The analysis of synthetic genetic regulatory networks in vivo is time consuming and suffers from a lack of environmental control, with exogenous synthetic components interacting with host processes resulting in undesired behavior. To overcome these issues, cell-free characterization of novel circuitry is becoming more prevalent. In vitro transcription and translation (IVTT) mixtures allow the regulation of the experimental environment and can be optimized for each unique system. The protocols presented here detail the fabrication of a multilayer microfluidic device that can be utilized to sustain IVTT reactions for prolonged durations. In contrast to batch reactions, where resources are depleted over time and (by-) products accumulate, the use of microfluidic devices allows the replenishment of resources as well as the removal of reaction products. In this manner, the cellular environment is emulated by maintaining an out-of-equilibrium environment in which the dynamic behavior of gene circuits can be investigated over extended periods of time. To fully exploit the multilayer microfluidic device, hardware and software have been integrated to automate the IVTT reactions. By combining IVTT reactions with the microfluidic platform presented here, it becomes possible to comprehensively analyze complex network behaviors, furthering our understanding of the mechanisms that regulate cellular processes.

The fabrication process of a PDMS-based, multilayer, microfluidic device that allows in vitro transcription and translation (IVTT) reactions to be performed over prolonged periods is described. Furthermore, a comprehensive overview of the hardware and software required to automate and maintain these reactions for prolonged durations is provided.

The limitations of cell-based synthetic biology are becoming increasingly apparent as researchers aim to develop larger and more complex synthetic genetic ...