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EoE Sub Articles

Monocyte-derived DCs were generated from leukapheresis products of healthy donors. For this, a positive vote from the local ethics committee has been obtained (reference number 4556). The experiments of the present study were performed in accordance with the recommendations of the ethics committee of the &#34;Friedrich-Alexander-Universit&#228;t Erlangen-N&#252;rnberg&#34; (reference number 4556). All donors approved a written informed consent, including the accordance with the Declaration of Helsinki.
1. Generation and handling of immature dendritic cells (iDCs) and mature dendritic cells (mDCs)
<ol>
	<li>Isolate human peripheral blood mononuclear cells (PBMCs) from leukoreduction system chambers (LRSCs) as previously described. Avoid cryopreservation of PBMCs and use them directly upon isolation to obtain higher DC yields.</li>
	<li>Generate human DCs from PBMCs of different healthy donors in T175 cell culture flasks as previously described. Briefly, use 350-400 millions of PBMCs in 30 mL of DC medium (RPMI 1640 without L-glutamine, 1% (v/v) Human Serum Type AB (AB-serum), 100 U/mL penicillin, 100 mg/mL streptomycin, 0.4 mM L-glutamine, 10 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES)) per cell culture flask for isolation of monocytes by adherence. After 1 h, wash off nonadherent fraction using RPMI 1640. Add fresh DC medium supplemented with 800 U/mL granulocyte-macrophage colony-stimulating factor (GM-CSF) and 250 U/mL interleukin-4 (IL-4), and incubate for 3 days.
	<ol>
		<li>On day 3 post adherence, add 5 mL of fresh DC medium containing GM-CSF and IL-4 with a final concentration of 400 U/mL and 250 U/mL per cell culture flask, respectively, for DC differentiation.</li>
		<li>To harvest iDCs, gently rinse loosely-adherent iDCs from the bottom of the cell culture flask, on day 4 post adherence. Repeat this step 2 times. For generation of mDCs, add maturation cocktail composed as follows: GM-CSF (final concentration: 40 U/mL), IL-4 (final concentration: 250 U/mL), interleukin-6 (IL-6, final concentration: 1000 U/mL), Interleukin-1 beta (IL-1&#946;, final concentration: 200 U/mL), Tumor Necrosis Factor alpha (TNF-&#945;, final concentration: 10 ng/mL), prostaglandin E2 (PGE2; final concentration: 1 &#956;g/mL).</li>
		<li>Six days post adherence (two days post induction of maturation using a cytokine cocktail), rinse mDCs from the bottom of the cell culture flask. Repeat this step two times. 
		NOTE: Immature and mature DCs can be sequentially generated from identical donors in 1 cell culture flask. To do so, (i) separate the appropriate number of iDCs and (ii) induce maturation of the remaining cells in the flasks using the cytokine cocktail listed in step 1.2.2.</li>
	</ol>
	</li>
	<li>Transfer iDCs or mDCs in the respective cell culture medium into 50 mL tubes. Harvest the cells via centrifugation at 300 x g for 5 min.
	<ol>
		<li>Gently resuspend (=wash) DCs in 5-10 mL of RPMI 1640 per cell culture flask. Combine respective DC suspensions in one tube.</li>
		<li>Define the cell number using a counting chamber or an alternative method. Avoid temperature alterations when handling iDCs, to reduce the risk of phenotypic changes.</li>
	</ol>
	</li>
</ol>
2. Flow cytometric analyses to monitor the phenotypic maturation status
<ol>
	<li>Transfer iDCs or mDCs (0.5 x 106) from step 1.3.1 into a 1.5 mL tube. Harvest the cells via centrifugation at 3390 x g for 1.5 min. Wash the cells once with FACS buffer (PBS supplemented with 2% fetal calf serum (FCS)).</li>
	<li>Resuspend the cells in 100 &#181;L of antibody staining solution (FACS buffer) containing specific fluorochrome-labeled antibodies against defined surface molecules.
	<ol>
		<li>Use the following antibodies to verify purity (CD3- fluorescein isothiocyanate [FITC], CD14- phycoerythrin [PE]) as well as maturation status of DCs (CD80-PacBlue [Pacific Blue]/-PE- cyanine5 [Cy5], CD11c-PE-Cy5, CCR7-PE-Cy7, CD83-APC, CD86-PE, MHCII-APC-Cy7).</li>
		<li>Prepare one unstained sample in 100 &#181;L of FACS buffer as a control.</li>
		<li>Stain the cells on ice in the dark for 30 min.</li>
	</ol>
	</li>
	<li>Subsequently wash the cells two times in 1 mL of FACS buffer and centrifuge at 3390 x g for 1.5 min.</li>
	<li>Finally, resuspend the cells in 200 &#181;L of FACS buffer supplemented with 2% paraformaldehyde (PFA) and analyze the cells by flow cytometry. Fixed cells can be stored at 4&#176; C in the dark up to 2 days.</li>
</ol>
3. Interference of HSV-1-induced autophagic flux via electroporation of iDCs using FIP200-siRNA
NOTE: The present protocol for siRNA electroporation was modified from Prechtel et al. (2007) and Gerer et al. (2017).
<ol>
	<li>Transfer iDCs (12 x 106) at day 3.5 post adherence into a 50 mL tube. Subsequently, centrifuge the cells at 300 x g for 5 min and discard the supernatant. In parallel, perform flow cytometric analysis to monitor the maturation status as described in step 2 (Use Life/Dead violet instead of CD80-PacBlue).</li>
	<li>Gently wash iDCs in 5 mL of OptiMEM without phenol red and centrifuge the cells at 300 x g for 5 min. Discard the supernatant and gently resuspend iDCs in 200 &#181;L of OptiMEM without phenol red, adjusting a cell concentration of 6 x 106/100 &#181;L. Do not place the cells on ice and avoid temperature alterations. Move on quickly and avoid long incubation periods of iDCs in OptiMEM without phenol red.</li>
	<li>Transfer either 75 pmol of FIP200-specific siRNA or 75 pmol of scrambled siRNA, as a control, into 4 mm electro cuvettes and add 100 &#181;L (6x106 cells) of the cell suspension. Directly pulse iDCs using the electroporation apparatus I, applying the following settings: 500 V for 1 ms.
	<ol>
		<li>Prior to the experimental procedure, prepare siRNA suspensions according to the manufacturer&#39;s instruction, aliquot and store them at -20 &#176;C. Thaw and keep them on ice when using these siRNAs for electroporation. Before electroporating the samples, perform a test pulse.</li>
	</ol>
	</li>
	<li>After electroporation, directly transfer iDC into 6-well plates with fresh pre-warmed DC medium (supplemented with 40 U/mL of GM-CSF and 250 U/mL of IL-4). Seed the cells at a final concentration of 1 x 106/mL and place them into an incubator. Do not rinse the cells out of the electro cuvette.</li>
	<li>After 48 h, first examine the morphology of electroporated iDCs microscopically. Then, harvest the cells using a cell scrapper and transfer them into 15 mL tubes. Rinse the wells with 1 mL of PBS supplemented with 0.01% ethylenediaminetetraacetic acid (EDTA) and transfer the solution in the respective tubes.</li>
	<li>Subsequently, split 6 x 106 iDCs per siRNA condition as described in the next steps.
	<ol>
		<li>Use 0.5 x 106 cells to assess the maturation status and cell viability as described in step 2. Use the following antibodies: CD11c-PE-Cy5, CCR7-PE-Cy7, CD83-APC, MHCII-APC-Cy7 and Life/Dead violet.</li>
		<li>Use 1 x 106 cells for Western blot analyses to verify FIP200-specific knockdown efficiency. Transfer and harvest the cells into a 1.5 mL safelock tube by centrifugation at 3390 x g for 1.5 min. Prepare cell lysates and perform Western blot analyses.</li>
		<li>Use the remaining cells (4.5 x 106) for HSV-1 infection experiments. For each experimental condition, transfer 2.25 x 106 iDCs into 2 mL tubes and either infect them with HSV1 at an multiplicity of infection (MOI) of 2 or add MNT buffer as a mock control. Perform the infection as described.</li>
		<li>At 20 h post infection (hpi), harvest the cells using a cell scraper and prepare cell lysates for Western blot analyses.</li>
	</ol>
	</li>
</ol>

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>4D-Nucleofector Core Unit (electroporation apparatus II)</td>
			<td>Lonza (Basel, Switzerland)</td>
			<td>AAF-1002B</td>
			<td></td>
		</tr>
		<tr>
			<td>AB-Serum</td>
			<td>Sigma Aldrich Chemie GmbH (Steinheim, Germany)</td>
			<td>H4522</td>
			<td>Dendritic cell cultivation</td>
		</tr>
		<tr>
			<td>ACD-A</td>
			<td>Sigma-Aldrich Chemie GmbH (Steinheim, Germany)</td>
			<td>9007281</td>
			<td></td>
		</tr>
		<tr>
			<td>Amaxa P3 Primary Cell 4D-Nucleofector X Kit L (electroporation kit apparatus II)</td>
			<td>Lonza (Basel, Switzerland)</td>
			<td>V4XP-3024</td>
			<td></td>
		</tr>
		<tr>
			<td>Amersham ECL Prime Western Blotting Detection Reagent</td>
			<td>GE Healthcare (Solingen, Germany)</td>
			<td>RPN2232</td>
			<td>Western Blot Detection</td>
		</tr>
		<tr>
			<td>Ammonium persulfate (APS)</td>
			<td>Sigma Aldrich Chemie GmbH (Steinheim, Germany)</td>
			<td>A3678</td>
			<td></td>
		</tr>
		<tr>
			<td>anti-mouse-IgG (mouse, polyclonal, HRP)</td>
			<td>Cell Signaling (Leiden, Netherlands)</td>
			<td>7076</td>
			<td>Western Blot detection</td>
		</tr>
		<tr>
			<td>anti-rabbit-IgG (goat, polyclonal, HRP)</td>
			<td>Cell Signaling (Leiden, Netherlands)</td>
			<td>7074</td>
			<td>Western Blot detection</td>
		</tr>
		<tr>
			<td>BD FACS Canto II Flow Cytometer</td>
			<td>BD Biosciences (Heidelberg, Germany)</td>
			<td>338962</td>
			<td></td>
		</tr>
		<tr>
			<td>Blotting Chamber Fastblot B44</td>
			<td>Biometra (G&#246;ttingen, Germany)</td>
			<td>846-015-100</td>
			<td></td>
		</tr>
		<tr>
			<td>CCR7 (mouse, Pe-Cy7)</td>
			<td>BioLegend (Fell, Germany)</td>
			<td>557648</td>
			<td>Flow cytometry 
			Dilution: 1:100 
			Clone: G043H7</td>
		</tr>
		<tr>
			<td>CD11c (mouse, Pe-Cy5)</td>
			<td>BD Biosciences (Heidelberg, Germany)</td>
			<td>561692</td>
			<td>Flow cytometry 
			Dilution: 1:100 
			Clone: B-ly6</td>
		</tr>
		<tr>
			<td>CD14 (mouse, PE)</td>
			<td>BD Biosciences (Heidelberg, Germany)</td>
			<td>555398</td>
			<td>Flow cytometry 
			Dilution: 1:100 
			Clone: M5E2</td>
		</tr>
		<tr>
			<td>CD3 (mouse, FITC)</td>
			<td>BD Biosciences (Heidelberg, Germany)</td>
			<td>555332</td>
			<td>Flow cytometry 
			Dilution: 1:100 
			Clone: UCHT1</td>
		</tr>
		<tr>
			<td>CD80 (mouse, V450)</td>
			<td>BD Biosciences (Heidelberg, Germany)</td>
			<td>560442</td>
			<td>Flow cytometry 
			Dilution: 1:100 
			Clone: L307.4</td>
		</tr>
		<tr>
			<td>CD83 (mouse, APC)</td>
			<td>eBioscience Thermo Fisher Scientific (Langenselbold, Germany)</td>
			<td>17-0839-41</td>
			<td>Flow cytometry 
			Dilution: 1:200 
			Clone: HB15e</td>
		</tr>
		<tr>
			<td>CD86 (mouse, PE)</td>
			<td>BD Biosciences (Heidelberg, Germany)</td>
			<td>553692</td>
			<td>Flow cytometry 
			Dilution: 1:100</td>
		</tr>
		<tr>
			<td>EVOS FL Cell Imaging</td>
			<td>System AMG/Life Technologies (Carlsbad, USA)</td>
			<td>AMF4300</td>
			<td></td>
		</tr>
		<tr>
			<td>FIP200 (rabbit)</td>
			<td>Cell Signaling (Leiden, Netherlands)</td>
			<td>12436</td>
			<td>Western Blot detection 
			Dilution: 1:1000 
			Clone: D10D11</td>
		</tr>
		<tr>
			<td>Gene Pulser II apparatus (electroporation apparatus I)</td>
			<td>BioRad Laboratories GmbH (M&#252;nchen, Germany)</td>
			<td>165-2112</td>
			<td></td>
		</tr>
		<tr>
			<td>GM-CSF (4x104 U/mL)</td>
			<td>Miltenyi Biotec (Bergisch Gladbach, Germany)</td>
			<td>130-093-868</td>
			<td></td>
		</tr>
		<tr>
			<td>HLA-DR (mouse, APC-Cy7)</td>
			<td>BioLegend (Fell, Germany)</td>
			<td>307618</td>
			<td>Flow cytometry 
			Dilution: 1:200 
			Clone: L243</td>
		</tr>
		<tr>
			<td>HSV-1/17+/CMV-EGFP/UL43</td>
			<td>BioVex</td>
			<td></td>
			<td>DC infection</td>
		</tr>
		<tr>
			<td>IL-1&#946; (0.1x106 U/mL)</td>
			<td>Cell Genix GmbH (Freiburg, Germany)</td>
			<td>1411-050</td>
			<td></td>
		</tr>
		<tr>
			<td>IL-4 (1x106 U/mL)</td>
			<td>Miltenyi Biotec (Bergisch Gladbach, Germany)</td>
			<td>130-093-924</td>
			<td></td>
		</tr>
		<tr>
			<td>IL-6 (1x106 U/mL)</td>
			<td>Cell Genix GmbH (Freiburg, Germany)</td>
			<td>1404-050</td>
			<td></td>
		</tr>
		<tr>
			<td>ImageQuant LAS 4000</td>
			<td>GE Healthcare (Solingen, Germany)</td>
			<td>28955810</td>
			<td></td>
		</tr>
		<tr>
			<td>L-glutamine</td>
			<td>Lonza (Basel, Switzerland)</td>
			<td>17-605E</td>
			<td></td>
		</tr>
		<tr>
			<td>LIVE/DEAD Fixable Violet dead cell stain kit</td>
			<td>Life Technologies (Carlsbad, CA, USA)</td>
			<td>L34964</td>
			<td>L/D staining in Flow cytometry</td>
		</tr>
		<tr>
			<td>Lymphoprep</td>
			<td>Alere Technologies AS (Oslo, Norway)</td>
			<td>04-03-9391/01</td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium chloride</td>
			<td>Carl Roth GmbH (Karlsruhe, Germany)</td>
			<td>A537.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Megafuge 2.0 RS</td>
			<td>Heraeus (Hanau, Germany)</td>
			<td>75015505</td>
			<td></td>
		</tr>
		<tr>
			<td>Neubauer counting chamber</td>
			<td>Brand (Wertheim, Germany)</td>
			<td>717805</td>
			<td></td>
		</tr>
		<tr>
			<td>Nunc Cell culture flasks (175.0 cm2)</td>
			<td>Thermo Scientific (Rockford, USA)</td>
			<td>159910</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde, 16 %</td>
			<td>Alfa Aesar, Haverhill, USA</td>
			<td>43368.9M</td>
			<td></td>
		</tr>
		<tr>
			<td>PerfectSpin 24 Plus</td>
			<td>Peqlab (Erlangen, Germany)</td>
			<td>C2500-R-PL</td>
			<td></td>
		</tr>
		<tr>
			<td>PGE2 (1 mg/mL)</td>
			<td>Pfizer (Berlin, Germany)</td>
			<td>BE130681</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffered saline (PBS)</td>
			<td>Lonza (Basel, Switzerland)</td>
			<td>17-512F</td>
			<td></td>
		</tr>
		<tr>
			<td>RestoreTM Western Blot Stripping Buffer</td>
			<td>Thermo Scientific, Rockford, USA</td>
			<td>21059</td>
			<td></td>
		</tr>
		<tr>
			<td>Rocking Platform wt 15</td>
			<td>Biometra (G&#246;ttingen, Germany)</td>
			<td>042-590</td>
			<td></td>
		</tr>
		<tr>
			<td>RotiBlock</td>
			<td>Carl Roth GmbH (Karlsruhe, Germany)</td>
			<td>A151.4</td>
			<td></td>
		</tr>
		<tr>
			<td>Roti-Load 1 (4x)</td>
			<td>Carl Roth GmbH (Karlsruhe, Germany)</td>
			<td>K929.3</td>
			<td></td>
		</tr>
		<tr>
			<td>Rotiphorese Gel 30 (37.5:1)</td>
			<td>Carl Roth GmbH (Karlsruhe, Germany)</td>
			<td>3029.1</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Lonza (Basel, Switzerland)</td>
			<td>12-167F</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium dodecyl Sulfate (SDS)</td>
			<td>Carl Roth GmbH (Karlsruhe, Germany)</td>
			<td>2326.2</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermomixer comfort</td>
			<td>Eppendorf (Hamburg, Germany)</td>
			<td>5355 000.011</td>
			<td></td>
		</tr>
		<tr>
			<td>TNF-&#945; (10 &#956;g/mL)</td>
			<td>Peprotech (Hamburg, Germany)</td>
			<td>300-01A</td>
			<td></td>
		</tr>
		<tr>
			<td>Tris</td>
			<td>Carl Roth GmbH (Karlsruhe, Germany)</td>
			<td>4855.3</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue solution (0.4 %)</td>
			<td>Sigma-Aldrich Chemie GmbH (Steinheim, Germany)</td>
			<td>T8154</td>
			<td></td>
		</tr>
		<tr>
			<td>Tween 20</td>
			<td>Carl Roth GmbH (Karlsruhe, Germany)</td>
			<td>9127.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Whatman 0.2 &#956;m nitrocellulose membrane</td>
			<td>GE Healthcare (Solingen, Germany)</td>
			<td>10600001</td>
			<td></td>
		</tr>
		<tr>
			<td>WhatmanTM Chromatography Paper 3 mm Chr</td>
			<td>Fisher Scientific GmbH (Schwerte, Germany)</td>
			<td>3030917</td>
			<td></td>
		</tr>
	</tbody>
</table>

sirna-based inhibition of autophagy in herpes simplex virus-infected immature dendritic cells

Source: D&#252;thorn, A., et al. <a href="https://app.jove.com/v/60190">siRNA Electroporation to Modulate Autophagy in Herpes Simplex Virus Type 1-Infected Monocyte-Derived Dendritic Cells.</a> J. Vis. Exp. (2019).
This video demonstrates a small interfering RNA (siRNA)-based technique to interfere with autophagic flux. A siRNA targeting FIP200 mRNA is introduced into monocyte-derived immature dendritic cells (iDCs) using electroporation, causing the knockdown of FIP200 expression and leading to the inhibition of nuclear lamin disruption via autophagy. Upon adding herpes simplex virus (HSV), the nuclear egress of viral progeny is inhibited due to the absence of lamin disruption via autophagic flux.

siRNA-Based Inhibition of Autophagy in Herpes Simplex Virus-Infected Immature Dendritic Cells

Monocyte-derived DCs were generated from leukapheresis products of healthy donors. For this, a positive vote from the local ethics committee has been ...

Take two electroporation cuvettes. One cuvette contains a small interfering RNA, or siRNA, designed to inhibit the production of FIP200, an autophagy-inducing protein.
The second cuvette contains a scrambled siRNA as a control that does not inhibit FIP200 production.
Add immature dendritic cells, or iDCs; electroporate for the cellular entry of siRNA and then plate the cells.
The internalized siRNA binds to an RNA-inducing silencing complex.
The complex with the FIP200-specific siRNA cleaves its target mRNA, inhibiting FIP200 production, while the control siRNA-treated iDCs produce FIP200.
Harvest the cells and add the herpes simplex virus. Upon viral envelope-cell membrane fusion, the released DNA enters the nucleus and leads to the production of viral proteins and nucleocapsids.
Viral proteins disrupt nuclear lamins. FIP200 forms a complex that triggers a signaling cascade, inducing autophagy of the disrupted lamins to target them for degradation and facilitating the escape of viral nucleocapsids into the cytoplasm. 
siRNA-mediated inhibition of FIP200 production restricts lamin autophagy, preventing nucleocapsid escape.
The cells are ready to assess siRNA-induced autophagy inhibition.

sirna-based-inhibition-autophagy-herpes-simplex-virus-infected

Research

JoVE Encyclopedia of Experiments

Immunology

Immunotherapy

Cellular Immunotherapy

47 Views. Źródło: Düthorn, A., et al. siRNA Electroporation to Modulation Autophagia in Herpes Simplex Virus Type 1-infected monocyt-based monocyt cells ( 2019). Ten film demonstruje technikę opartą na małym interferującym RNA (siRNA) do zakłócania przepływu autofagicznego. SiRNA ukierunkowane na mRNA FIP200 jest wprowadzane do niedojrzałych komórek dendrytycznych (iDC) pochodzących z monocytów za pomocą elektroporacji, powodując obniżenie ekspresji FIP200 i prowadząc do zahamowania r...

Video: Hamowanie autofagii oparte na siRNA w niedojrzałych komórkach dendrytycznych zakażonych wirusem opryszczki pospolitej - Concept

Dissection of Enhancer Function Using Multiplex CRISPR-based Enhancer Interference in Cell Lines

Multiple enhancers often regulate a given gene, yet for most genes, it remains unclear which enhancers are necessary for gene expression, and how these enhancers combine to produce a transcriptional response. As millions of enhancers have been identified, high-throughput tools are needed to determine enhancer function on a genome-wide scale. Current methods for studying enhancer function include making genetic deletions using nuclease-proficient Cas9, but it is difficult to study the combinatorial effects of multiple enhancers using this technique, as multiple successive clonal cell lines must be generated. Here, we present Enhancer-i, a CRISPR interference-based method that allows for functional interrogation of multiple enhancers simultaneously at their endogenous loci. Enhancer-i makes use of two repressive domains fused to nuclease-deficient Cas9, SID and KRAB, to achieve enhancer deactivation via histone deacetylation at targeted loci. This protocol utilizes transient transfection of guide RNAs to enable transient inactivation of targeted regions and is particularly effective at blocking inducible transcriptional responses to stimuli in tissue culture settings. Enhancer-i is highly specific both in its genomic targeting and its effects on global gene expression. Results obtained from this protocol help to understand whether an enhancer is contributing to gene expression, the magnitude of the contribution, and how the contribution is affected by other nearby enhancers.

This protocol describes the steps needed to design and perform multiplexed targeting of enhancers with the deactivating fusion protein SID4X-dCas9-KRAB, also known as enhancer interference (Enhancer-i). This protocol enables the identification of enhancers that regulate gene expression and facilitates the dissection of relationships between enhancers regulating a common target gene.

Multiple enhancers often regulate a given gene, yet for most genes, it remains unclear which enhancers are necessary for gene expression, and how these ...

JoVE Journal

Genetics

Preparation of Exosomes for siRNA Delivery to Cancer Cells

Extracellular vesicles, in particular exosomes, have recently gained interest as novel drug delivery vectors due to their biological origin, abundance, and intrinsic capability in intercellular delivery of various biomolecules. This work establishes an isolation protocol to achieve high yield and high purity of exosomes for siRNA delivery. Human Embryonic Kidney cells (HEK-293 cells) are cultured in bioreactor flasks and the culture supernatant (hereon referred to as conditioned medium) is harvested on a weekly basis to allow for enrichment of HEK-293 exosomes. The conditioned medium (CM) is pre-cleared of dead cells and cellular debris by differential centrifugation and is subjected to ultracentrifugation onto a sucrose cushion followed by a washing step, to collect the exosomes. Isolated HEK-293 exosomes are characterized for yield, morphology and exosomal marker expression by nanoparticle tracking analysis, protein quantification, electron microscopy and flow cytometry, respectively. Small interfering RNA (siRNA), fluorescently labeled with Atto655, is loaded into exosomes by electroporation and excess siRNA is removed by gel filtration. Cell uptake in PANC-1 cancer cells, after 24 h incubation at 37 &#176;C, is confirmed by flow cytometry. HEK-293 exosomes are 107.0 &#177; 8.2 nm in diameter. The exosome yield and particle-to-protein ratio (P:P) ratio are 6.99 &#177; 0.22 &#215; 1012 particle/mL and 8.3 &#177; 1.7 &#215; 1010 particle/&#181;g, respectively. The encapsulation efficiency of siRNA in exosomes is ~ 10-20%. Forty percent of the cells show positive signals for Atto655 at 24 h post-incubation. In conclusion, exosome isolation by ultracentrifugation onto sucrose cushion offers a combination of good yield and purity. siRNA could be successfully loaded into exosomes by electroporation and subsequently delivered into cancer cells in vitro. This protocol offers a standard procedure for developing siRNA-loaded exosomes for efficient delivery to cancer cells.

An exosome is a new generation of drug delivery carriers. We established an exosome isolation protocol with high yield and purity for siRNA delivery. We also encapsulated fluorescently labelled non-specific siRNA into exosomes and investigated the cellular uptake of siRNA-loaded exosomes in cancer cells.

Extracellular vesicles, in particular exosomes, have recently gained interest as novel drug delivery vectors due to their biological origin, abundance, ...

Cancer Research

Nanoparticle-mediated siRNA Gene-silencing in Adult Zebrafish Heart

Mammals have a very limited capacity to regenerate the heart after myocardial infarction. On the other hand, the adult zebrafish regenerates its heart after apex resection or cryoinjury, making it an important model organism for heart regeneration study. However, the lack of loss-of-function methods for adult organs has restricted insights into the mechanisms underlying heart regeneration. RNA interference via different delivery systems is a powerful tool for silencing genes in mammalian cells and model organisms. We have previously reported that siRNA-encapsulated nanoparticles successfully enter cells and result in a remarkable gene-specific knockdown in the regenerating adult zebrafish heart. Here, we present a simple, rapid, and efficient protocol for the dendrimer-mediated siRNA delivery and gene-silencing in the regenerating adult zebrafish heart. This method provides an alternative approach for determining gene functions in adult organs in zebrafish and can be extended to other model organisms as well.

It remains a major challenge to develop conditional gene-knockout or effective gene-knockdown in adult zebrafish organs. Here we report a protocol for performing nanoparticle-mediated siRNA gene-silencing in adult zebrafish heart, thus providing a new loss-of-function method for studying adult organs in zebrafish and other model organisms.

Mammals have a very limited capacity to regenerate the heart after myocardial infarction. On the other hand, the adult zebrafish regenerates its heart ...

siRNA-Based Inhibition of Autophagy in Herpes Simplex Virus-Infected Immature Dendritic Cells

Transkrypcja

siRNA-Based Inhibition of Autophagy in Herpes Simplex Virus-Infected Immature Dendritic Cells