Name: development of an economical dna delivery system by "acufection" and its application to skin research
Uploaded: 2017-04-19T12:30:00
Description: Watch this Scientific Journal Video about Development of an Economical DNA Delivery System by "Acufection" and its Application to Skin Research at JoVE.com

This work was supported by grant from the Ministry of Science and Technology (MOST 103-2633-B-002-002; 104-2320-B-002-048). We thank Drs. Betty Wu-Hsieh and Chien-Kuo Lee at NTU, Leigh Zerboni at Stanford University and Dr. Peter Hoffmann at the University of Hawaii for reading the manuscript, Yun Chien at NTU for technical assistance, and Dr. Wen-Chi Wei at Agriculture Biotechnology Research Center at Academia Sinica for technical advice.

Female mice at 8 - 12 weeks of age were used for this study. C57/BL6 wild-type (WT) and IL-15 deficient (Il15-/-) mice were purchased from National Laboratory Animal Center (NLAC), Taiwan and Taconic Farm, respectively. IL-15-deficient (Il15-/-) andIL-15-dominant (Il15+/- and Il15+/+) showed a 1:3 ratio in the second generation from the cross of Il15+/- heterozygotes. The genotype of Il15-/- mice was confirmed by PCR analysis. Mice were maintained in the Sp...

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J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imiquimod+(Aldara):+modifying+the+immune+response.">Imiquimod (Aldara): modifying the immune response.</a> Dermatol Nurs. 14, 268-270 (2002).</li><li>van der Fits, 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=Imiquimod-induced+psoriasis-like+skin+inflammation+in+mice+is+mediated+via+the+IL-23/IL-17+axis.">Imiquimod-induced psoriasis-like skin inflammation in mice is mediated via the IL-23/IL-17 axis.</a> J Immunol. 182, 5836-5845 (2009).</li><li>Sumida, H., 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=Interplay+between+CXCR2+and+BLT1+facilitates+neutrophil+infiltration+and+resultant+keratinocyte+activation+in+a+murine+model+of+imiquimod-induced+psoriasis.">Interplay between CXCR2 and BLT1 facilitates neutrophil infiltration and resultant keratinocyte activation in a murine model of imiquimod-induced psoriasis.</a> J Immunol. 192, 4361-4369 (2014).</li><li>Bamford, R. 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The most critical step to ensure the expression of the acufected plasmid DNA is to evenly oscillate and loosen the horny layer of the skin. While pushing the needles gently without cutting the skin, the force should be hard enough to depress the surface. To facilitate absorption of DNA in 10 &#956;L solution on a 1 cm x 1 cm surface area, the needles should oscillate up-and-down for about 100 times in 30 s. One can determine the force that needs to prick the skin and by noting the number of times that is needed to yield ...

Skin is the first-line of host defense. Keratinocytes (KCs) are the major cell type in the skin of humans and mice. In response to environmental stimuli (e.g. sunlight, oxygen, chemicals and pathogenic invasion), KCs are activated and produce a wide array of proinflammatory cytokines and chemokines such as IL-8, IL-6, IL-1&#945;, IL-1&#946;, TNF-&#945; and GM-CSF1. Together they trigger the recruitment of immune cells to the skin. Aggravated cutaneous inflammation is often associated with numerous human diseases including acute ectopic contact dermatitis and chronic T cell-mediated inflammation (e.g. allergic contact dermatitis and psoriasis)2. Modulating proinflammatory responses in the skin by inhibiting KC activation is a plausible approach to treat cutaneous inflammation. This protocol describes a new approach to transiently express a cytokine gene in the epidermis in order to study immune response consequential to such a treatment in the skin.
The epidermis composes the most superficial layer of the skin. It serves as a physical barrier keeping external substances such as nucleic acids and pathogens from entering the deeper layers of the skin. Several needle-free techniques have been established for epidermal DNA transfer3,4. DNA in solution or associated with cationic liposomes or adenovirus vectors has been directly applied to the epidermis modified with techniques such as the removal of the stratum corneum or the treatment with depilating reagent. Removal of the cornified epithelium facilitates DNA crossing the epidermal barrier and interaction with keratinocytes and Langerhans cells to induce immune responses5. While a large surface area is available for DNA transfer and this approach does not involve needles, there are disadvantages including the requirement for the large quantities of DNA (10 - 100 &#956;g), harsh treatment on the skin by stripping, and the inconsistent results in inducing immune response in the immunized animals without DNA delivery booster6. Microparticle-mediated intracellular delivery of naked DNA to the skin has been shown to be highly efficient and reproducible for inducing immune response7,8. A hand-held gene gun has been used to bombard the skin target site with plasmid DNA-coated gold particles 2 &#956;m-diameter in size by means of pressurized helium air flow9. The plasmid DNA is presumably taken up by KCsand dendritic cells (DCs) in the skin and the protein is locally expressed or being transported to draining lymph nodes by DCs10. Although the gene gun system is simple and requires limited technical experience, the cost for preparing and delivering the &#34;DNA bullet&#34; (i.e. gold powders, helium gas) and for the gene gun itself has limited its general application. In addition, the requirement for a helium gas delivery system limits the ease of gene gun transport when the experiments are conducted at different locations. Microseeding has been demonstrated to achieve a higher efficiency of gene transfer than single injection and particle bombardment11. Microseeding uses a tattoo gun to deliver DNA to the skin without the use of particle beads11. Oscillating the microneedles on the skin using this approach is likely to directly scrape the cell membrane and thus transfer DNA to multiple cells at the same time. However, pain associated with the large number of injections with 0.254 mm-diameter needles is a disadvantage.
Here we provide an alternative approach to DNA delivery in vivo. The &#34;acufection&#34; protocol we described here provides an economical and efficient way to deliver plasmid DNA in mouse skin. Briefly, ten acupuncture needles (0.2 mm in diameter x 13 mm in length) were bound in a bundle by adhesive tape. A volume of 10 &#956;L of PBS with 10 &#956;g of plasmid DNA containing the transgene of interest was placed on the shaved, depilatory cream-treated flank skin. By using the acupuncture needle bundle to oscillate the surface (1 cm x 1 cm) of the skin, the keratins at the horny layer were loosened and the plasmid DNA applied to the surface was absorbed into the epidermis. Skin damage was monitored and found to be minimal. Expression of the transfected gene in the acufected skin was confirmed by both quantitative real-time PCR (qRT-PCR) and ELISA. The immune modulatory effects of acufection-delivered IL-15&#916;E7 on cutaneous inflammation were demonstrated using the IMQ-treated mouse model12. While acufection proves to be an easy and less demanding method for DNA delivery in vivo, the optimal amount of DNA for different genes and the times to prick the skin have to be carefully optimized to obtain reproducible results.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Accu Handy Needle</td>
			<td>Accu</td>
			<td>36Gx0.5</td>
			<td>Medical device</td>
		</tr>
		<tr>
			<td>NairTM Lotion</td>
			<td>Church &#38; Dwight</td>
			<td>N/A</td>
			<td>Use to remove hair</td>
		</tr>
		<tr>
			<td>Shandon Xyline substitute</td>
			<td>Thermo Fisher Scientific</td>
			<td>6764506</td>
			<td>Deparaffinization</td>
		</tr>
		<tr>
			<td>Avertin (2,2,2-Tribromethanol)</td>
			<td>Sigma-Aldrich</td>
			<td>T4,840-2</td>
			<td>Anesthesia</td>
		</tr>
		<tr>
			<td>2-methyl-2-butanol</td>
			<td>Sigma-Aldrich</td>
			<td>152463</td>
			<td>Solvent for the dissolution of avertin</td>
		</tr>
		<tr>
			<td>DifcoTM LB broth, Miller</td>
			<td>BD</td>
			<td>244620</td>
			<td>Propagation and maintenance of E. coli for molecular biology</td>
		</tr>
		<tr>
			<td>QIAGEN&#9415; Plasmid Midi Kit</td>
			<td>QIAGEN</td>
			<td>12143</td>
			<td>Purification of plasmid DNA from E. coli</td>
		</tr>
		<tr>
			<td>Mouse IL-15/IL-15R Complex ELISA Ready-SET-Go kit</td>
			<td>eBioscience</td>
			<td>88-7215</td>
			<td>Measure IL-15 protein</td>
		</tr>
		<tr>
			<td>Anti-mouse Ly6G</td>
			<td>BioLegend</td>
			<td>127601</td>
			<td>Antibody used for immunohistochemical stain</td>
		</tr>
		<tr>
			<td>anti-mouse Ki-67</td>
			<td>eBioscience</td>
			<td>14-5698-80</td>
			<td>Antibody used for immunohistochemical stain</td>
		</tr>
		<tr>
			<td>Simple Stain Mouse MAXPO (Rat)</td>
			<td>Nichirei Biosciences</td>
			<td>414341F</td>
			<td>Reagent to block background signal in mouse-on-mouse stain</td>
		</tr>
		<tr>
			<td>DAB Peroxidase (HRP) Substrate Kit</td>
			<td>Vector Laboratories</td>
			<td>SK-4100</td>
			<td>Peroxidse substrate for immunohistochemical stain</td>
		</tr>
		<tr>
			<td>Ultra V block</td>
			<td>Thermo Fisher Scientific</td>
			<td>TA-060-UB</td>
			<td>Reduce nonspecific background staining</td>
		</tr>
		<tr>
			<td>Methyl green</td>
			<td>Sigma-Aldrich</td>
			<td>M8884</td>
			<td>Nuclear staining</td>
		</tr>
		<tr>
			<td>Vecta MountTM</td>
			<td>Vector Laboratories</td>
			<td>M-5000</td>
			<td>Permanently preserving histochemical stains</td>
		</tr>
		<tr>
			<td>Protease inhibitor cocktail tablets</td>
			<td>Roche</td>
			<td>04-693-116-001</td>
			<td>Inhibit protease activity in cell lysate</td>
		</tr>
		<tr>
			<td>Aldara cream</td>
			<td>3M Parmaceuticals</td>
			<td>N/A</td>
			<td>5% imiquimod cream</td>
		</tr>
		<tr>
			<td>Bessman Tissue Pulverizer</td>
			<td>Spectrum Labs</td>
			<td>189475</td>
			<td>Use to pulverize skin tissue</td>
		</tr>
		<tr>
			<td>ABI7900HT cycler</td>
			<td>Thermo Fisher Scientific</td>
			<td>N/A</td>
			<td>quantitative real-time PCR assay</td>
		</tr>
		<tr>
			<td>Camcorder</td>
			<td>Panasonic</td>
			<td>HDC-SD60</td>
			<td>Image documentation</td>
		</tr>
		<tr>
			<td>Axio Scope.A1</td>
			<td>ZEISS</td>
			<td>N/A</td>
			<td>Bright-field microscopy</td>
		</tr>
		<tr>
			<td>ScanScope&#9415; XT</td>
			<td>Aperio</td>
			<td>N/A</td>
			<td>Whole-field image scanner</td>
		</tr>
		<tr>
			<td>MetaMorph&#9415; Research Imaging</td>
			<td>Molecular Devices</td>
			<td>N/A</td>
			<td>Quantitative analysis of skin thickness and immune-reactive cells</td>
		</tr>
	</tbody>
</table>

development of an economical dna delivery system by "acufection" and its application to skin research

Dysregulation of immune response in skin is associated with numerous human skin disorders. Direct transfer of immune-related genes into skin tissue is a fascinating approach to investigate immune modulation of cutaneous inflammation in mouse models of human diseases. Here we present a cost-effective protocol that delivered naked DNA in mouse skin and leads to transgene expression. The method is coined &#34;acufection&#34;, denoting acupuncture-mediated DNA transfection. To perform acufection, mouse skin was first infused with DNA in phosphate-buffered saline (PBS) and then pricked lightly with a bundle of acupuncture needles to facilitate the absorption of DNA and transfection into cells. The plasmid DNA is presumably taken up by the keratinocyte and dendritic cells (DCs) in the skin and expressed into protein. Mechanical prick with the needles per se did not cause skin damage or induce keratinocyte activation. The expression of the transfected genes was detected in the skin at both transcriptional and translational levels following acufection for 2 days and maintained up to 7 days. The primary goal for the development of this acufection method was to investigate a previously undefined isoform of IL-15. Using this method, an alternatively spliced IL-15 isoform with partially deleted exon 7 (IL-15&#916;E7) was expressed in the skin and subsequently treated with a Toll-like receptor 7 (TLR7) agonist, imiquimod (IMQ), to induce inflammation. Acufection-delivered IL-15&#916;E7 in skin suppressed keratinocyte proliferation, epidermal thickness and neutrophil recruitment in IMQ-induced cutaneous inflammation. With increasing interest in identifying the regulatory mechanisms of cutaneous inflammation, the protocol described here provides a cost effective and versatile alternative to the gene gun system or microseeding for DNA delivery in vivo. It may potentially allow discovery of the function of a novel gene in the skin or for investigating new treatment for cutaneous diseases.

While some redness was evident within the first hour after pricking with acupuncture needles, the skin cleared on day 2 and no adverse skin reaction up to day 7 was observed after pricking (Figure 2A). Needle pricking induced very low level of epidermal orthokeratosis and minimal dermal infiltration by H&#38;E analysis compared with untreated skin (Figure 2B). The epidermal thickness (Figure 2C) and ...

Watch this Scientific Journal Video about Development of an Economical DNA Delivery System by "Acufection" and its Application to Skin Research at JoVE.com

Development of an Economical DNA Delivery System by &quot;Acufection&quot; and its Application to Skin Research

This protocol is a cost-effective alternative for expressing naked plasmid DNA in mouse skin. The overall goal of the protocol is to deliver immune-related genes into skin tissue to delineate the functional role of a specific gene in cutaneous inflammation.

Development of an Economical DNA Delivery System by "Acufection" and its Application to Skin Research

Dysregulation of immune response in skin is associated with numerous human skin disorders. Direct transfer of immune-related genes into skin tissue is a ...

The overall goal of this procedure is to deliver immune related genes into skin tissue to delineate the functional role of a specific gene in a cutaneus inflammation. This method can aid in discovering the function of a novel gene in the skin. For the development of new therapies for cutaneus disease such a psoriasis.The main advantage of this technique is that it provides a cost effective way to express plasmid DNA in mouse skin. To prepare the plasmid DNA inoculate three milliliters of antibiotic supplemented LB medium with the previously transformed and selected bacterial colony. Incubate the culture overnight on a shaker at 37 degrees celsius.After the overnight incubation dilute the bacterial culture in 250 milliliters of LB medium, supplemented with antibiotics to scale-up the culture. Incubate the culture overnight at 37 degrees Celsius with shaking. Use a high-quality endotoxin free plasmid preparation kit to prepare a large quantity of DNA.Dilute the obtained plasmid DNA in sterile PBS to a final concentration of one milligram per milliliter. After anesthetizing the mouse, apply veterinary ophthalmologic ointment to its eyes to prevent dryness. Then shave the skin on the back of the animal.And apply a depilatory cream to dissolve keratin proteins in the remaining hair shafts. Following depilation wipe off the cream with water soaked cotton. Using a sterile cotton swab, soaked in 70%ethanol disinfect the skin surface and mark the target skin area with the previously prepared template Apply 10 microliters of the DNA solution containing 10 micrograms of plasmid DNA to the desired skin area.To acufect the mouse, hold the acupuncture apparatus perpendicularly to the skin and repetitively puncture the designated surface. Either 100 times over 30 seconds or until the solution applied to the skin absorbs. To achieve successful plasmid DNA expression in the skin tissue, it is important avoid cutting deep into the skin and to make sure the DNA solution is well absorbed.After completing the procedure place the acufected mouse on a heating pad to maintain its body temperature until recovery from anesthesia. When the mouse regains sufficient consciousness return it to its cage and provide water and food. Closely monitor the mouse for any symptoms of discomfort including behavioral changes, abnormal appearance for the first 48 hours after the procedure.Mark the flank skin covering the area of two centimeters by two centimeters previously acufected with IL-15deltaE7. Then using a cotton applicator apply Imiquimod cream topically to the designated surface area. To monitor daily changes of the Imiquimod treated dorsal skin, have one researcher record while the second holds the mouse securely and exposes the treated area to the view of the high definition camcorder.Observe for such changes as silvery scale, plaque or erythema on the treated skin. After euthanizing the mouse as described, make a horizontal incision at the base of the tail using a pair of serological scissors and widen the cut bilaterally towards the base of each hind limb. Then proceed with vertical cuts that align with the flanks and reach each base of the four limbs.Carefully peel the skin from the underlying issue starting with the tail towards the head of the animal. Using scissors excise the dorsal skin and transfer the obtained sample to a sterile Petri dish. With a scalpel, excise a suitable sample of the target skin.Then immediately freeze it in liquid nitrogen. To pulverize the skin tissue, place the frozen sample at the center of a previously chilled two compartment tissue pulverizor equipped with handles and a pestle and use a lead hammer on the mortar. Immediately transfer the pulverized tissue into new tubes containing the reagents appropriate for any subsequent analysis.Begin the staining procedure by heating the slides of the formalin fixed paraffin embedded skin sections prepared as detailed in the text protocol, at 65 degrees celsius for 15 minutes. Immerse the slides twice in xylene for five minutes. Then rehydrate the slides through an ethanol gradient.Finally, wash the slides in tap water for three minutes before staining. For Immunohistochemical staining, first draw a circle around the tissue with waterproof pen and then incubate the section with blocking solution to exclude non-specific background staining. After blocking, was the side in PBS.Next pipette the diluted primary antibody onto the section and incubate it for 60 minutes at room temp temperature. Wash the slides thrice in TBST for five minutes. Then overlay one drop of the labeled polymer over the section and incubate the slide at room temperature for 40 minutes.Afterward, wash the slide thrice in TBST for five minutes changing the solution between washes. Then add 100 microliters of DAB solution onto the tissue sections and allow it to react at room temperature. Until a brown product is observed under the microscope.Then wash the slides in water to stop peroxidase activity. Counter stain the section in Methyl Green solution, which specifically binds to DNA for five seconds. Wash the slides three times in PBS for five minutes each.Overlay the stained section with eight microliters of permanent mounting medium and cover it with a cover slip. Finally, image the slides as described in the text protocol. Pictured here is a control mouse and a mouse that was acufected for one hour, two days, five days or seven days prior to when the photograph was taken.As shown here, the acufection procedure did not cause noticeable skin damage. Furthermore, acufection did not influence either skin thickness or the number of Ki67 positive cells. Further confirming that the procedure does not cause tissue disruption or epidermal cell proliferation.The expression of CXCL-1 and IL-6 measured using qRT-PCR. Confirms minimal keratinocyte activation observed under acufection. On the other hand, qRT-PCR and ELISA demonstrated the pronounced expression of IL-15 in the skin of mice acufected with the IL-15 gene.Ultimately, acufection mediated delivery of the IL-15deltaE7 gene to skin tissue prevents the development of flaky skin and neutrophil infiltration Imiquimod treated mice. Once mastered this procedure can be done in 12 minutes if it is performed properly. While attempting this procedure it is important to remember to prepare a new bundle of needles for each acufection ans a batch of high quality plasmid DNA.Following this procedure, other methods like virus infection can be performed in order to answer additional questions like the function of a novel gene in modulating antiviral immune response. After its development this will pave the way for researchers in the field of immunology to explore the immune response in the skin. After watching this video, you should have a good understanding of how to induce the expression of plasmid DNA in the mouse skin in a cost effective manner.

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Research

JoVE Journal

Immunology and Infection

Development of a Negative Selectable Marker for Entamoeba histolytica

Entamoeba histolytica is the causative agent of amebiasis and infects up to 10% of the world's population. The molecular techniques that have enabled the up- and down-regulation of gene expression rely on the transfection of stably maintained plasmids. While these have increased our understanding of Entamoeba virulence factors, the capacity to integrate exogenous DNA into genome, which would allow reverse genetics experiments, would be a significant advantage in the study of this parasite. The challenges presented by this organism include inability to select for homologous recombination events and difficulty to cure episomal plasmid DNA from transfected trophozoites. The later results in a high background of exogenous DNA, a major problem in the identification of trophozoites in which a bona fide genomic integration event has occurred. We report the development of a negative selection system based upon transgenic expression of a yeast cytosine deaminase and uracil phosphoribosyl transferase chimera (FCU1) and selection with prodrug 5-fluorocytosine (5-FC). The FCU1 enzyme converts non-toxic 5-FC into toxic 5-fluorouracil and 5-fluorouridine-5'-monophosphate. E. histolytica lines expressing FCU1 were found to be 30 fold more sensitive to the prodrug compared to the control strain.

Development of a Negative Selectable Marker for Entamoeba histolytica

We report development of a negative selection system in E. histolytica based upon transgenic expression of a chimeric protein (FCU1) and selection with the prodrug 5-fluorocytosine. The FCU1 protein is a fusion of yeast cytosine deaminase and uracil phosphoribosyltransferase. Expression of FCU1 resulted in increased E. histolytica sensitivity towards 5-fluorocytosine.

Entamoeba histolytica is the causative agent of amebiasis and infects up to 10% of the world's population. The molecular techniques that have enabled the ...

Development of Cell-type specific anti-HIV gp120 aptamers for siRNA delivery

The global epidemic of infection by HIV has created an urgent need for new classes of antiretroviral agents. The potent ability of small interfering (si)RNAs to inhibit the expression of complementary RNA transcripts is being exploited as a new class of therapeutics for a variety of diseases including HIV. Many previous reports have shown that novel RNAi-based anti-HIV/AIDS therapeutic strategies have considerable promise; however, a key obstacle to the successful therapeutic application and clinical translation of siRNAs is efficient delivery. Particularly, considering the safety and efficacy of RNAi-based therapeutics, it is highly desirable to develop a targeted intracellular siRNA delivery approach to specific cell populations or tissues. The HIV-1 gp120 protein, a glycoprotein envelope on the surface of HIV-1, plays an important role in viral entry into CD4 cells. The interaction of gp120 and CD4 that triggers HIV-1 entry and initiates cell fusion has been validated as a clinically relevant anti-viral strategy for drug discovery. 
Herein, we firstly discuss the selection and identification of 2'-F modified anti-HIV gp120 RNA aptamers. Using a conventional nitrocellulose filter SELEX method, several new aptamers with nanomolar affinity were isolated from a 50 random nt RNA library. In order to successfully obtain bound species with higher affinity, the selection stringency is carefully controlled by adjusting the conditions. The selected aptamers can specifically bind and be rapidly internalized into cells expressing the HIV-1 envelope protein. Additionally, the aptamers alone can neutralize HIV-1 infectivity. Based upon the best aptamer A-1, we also create a novel dual inhibitory function anti-gp120 aptamer-siRNA chimera in which both the aptamer and the siRNA portions have potent anti-HIV activities. Further, we utilize the gp120 aptamer-siRNA chimeras for cell-type specific delivery of the siRNA into HIV-1 infected cells. This dual function chimera shows considerable potential for combining various nucleic acid therapeutic agents (aptamer and siRNA) in suppressing HIV-1 infection, making the aptamer-siRNA chimeras attractive therapeutic candidates for patients failing highly active antiretroviral therapy (HAART).

Several 2&#x2019;-Fluoro RNA aptamers against HIV-1Ba-L gp120 with nanomole affinity are isolated from a RNA library by in vitro SELEX procedure. A new dual inhibitory function anti-gp120 aptamer-siRNA chimera is created and shows considerable promise for systemic anti-HIV therapy.

The global epidemic of infection by HIV has created an urgent need for new classes of antiretroviral agents. The potent ability of small interfering ...

Application of a Mouse Ligated Peyer&#x2019;s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells

The inside of our gut is inhabited with enormous number of commensal bacteria. The mucosal surface of the gastrointestinal tract is continuously exposed to them and occasionally to pathogens. The gut-associated lymphoid tissue (GALT) play a key role for induction of the mucosal immune response to these microbes1, 2. To initiate the mucosal immune response, the mucosal antigens must be transported from the gut lumen across the epithelial barrier into organized lymphoid follicles such as Peyer's patches. This antigen transcytosis is mediated by specialized epithelial M cells3, 4. M cells are atypical epithelial cells that actively phagocytose macromolecules and microbes. Unlike dendritic cells (DCs) and macrophages, which target antigens to lysosomes for degradation, M cells mainly transcytose the internalized antigens. This vigorous macromolecular transcytosis through M cells delivers antigen to the underlying organized lymphoid follicles and is believed to be essential for initiating antigen-specific mucosal immune responses. However, the molecular mechanisms promoting this antigen uptake by M cells are largely unknown. We have previously reported that glycoprotein 2 (Gp2), specifically expressed on the apical plasma membrane of M cells among enterocytes, serves as a transcytotic receptor for a subset of commensal and pathogenic enterobacteria, including Escherichia coli and Salmonella enterica serovar Typhimurium (S. Typhimurium), by recognizing FimH, a component of type I pili on the bacterial outer membrane 5. Here, we present a method for the application of a mouse Peyer's patch intestinal loop assay to evaluate bacterial uptake by M cells. This method is an improved version of the mouse intestinal loop assay previously described 6, 7. The improved points are as follows: 1. Isoflurane was used as an anesthetic agent. 2. Approximately 1 cm ligated intestinal loop including Peyer's patch was set up. 3. Bacteria taken up by M cells were fluorescently labeled by fluorescence labeling reagent or by overexpressing fluorescent protein such as green fluorescent protein (GFP). 4. M cells in the follicle-associated epithelium covering Peyer's patch were detected by whole-mount immunostainig with anti Gp2 antibody. 5. Fluorescent bacterial transcytosis by M cells were observed by confocal microscopic analysis. The mouse Peyer's patch intestinal loop assay could supply the answer what kind of commensal or pathogenic bacteria transcytosed by M cells, and may lead us to understand the molecular mechanism of how to stimulate mucosal immune system through M cells.

Application of a Mouse Ligated Peyer&amp;#8217;s Patch Intestinal Loop Assay to Evaluate Bacterial Uptake by M cells

M cells in a specialized follicle-associated epithelium covering Peyer&#x2019;s patches play an important role for the mucosal immunosurveillance in gut-associated lymphoid tissue. Here we described the evaluation method for bacterial transcytosis by M cells in vivo. This method provides a method to understand M-cell function in the immune system.

The inside of our gut is inhabited with enormous number of commensal bacteria. The mucosal surface of the gastrointestinal tract is continuously exposed ...

Purification and Visualization of Lipopolysaccharide from Gram-negative Bacteria by Hot Aqueous-phenol Extraction

Lipopolysaccharide (LPS) is a major component of Gram-negative bacterial outer membranes. It is a tripartite molecule consisting of lipid A, which is embedded in the outer membrane, a core oligosaccharide and repeating O-antigen units that extend outward from the surface of the cell1, 2. LPS is an immunodominant molecule that is important for the virulence and pathogenesis of many bacterial species, including Pseudomonas aeruginosa, Salmonella species, and Escherichia coli3-5, and differences in LPS O-antigen composition form the basis for serotyping of strains. LPS is involved in attachment to host cells at the initiation of infection and provides protection from complement-mediated killing; strains that lack LPS can be attenuated for virulence6-8. For these reasons, it is important to visualize LPS, particularly from clinical isolates. Visualizing LPS banding patterns and recognition by specific antibodies can be useful tools to identify strain lineages and to characterize various mutants. 
In this report, we describe a hot aqueous-phenol method for the isolation and purification of LPS from Gram-negative bacterial cells. This protocol allows for the extraction of LPS away from nucleic acids and proteins that can interfere with visualization of LPS that occurs with shorter, less intensive extraction methods9. LPS prepared this way can be separated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE) and directly stained using carbohydrate/glycoprotein stains or standard silver staining methods. Many anti-sera to LPS contain antibodies that cross-react with outer membrane proteins or other antigenic targets that can hinder reactivity observed following Western immunoblot of SDS-PAGE-separated crude cell lysates. Protease treatment of crude cell lysates alone is not always an effective way of removing this background using this or other visualization methods. Further, extensive protease treatment in an attempt to remove this background can lead to poor quality LPS that is not well resolved by any of the aforementioned methods. For these reasons, we believe that the following protocol, adapted from Westpahl and Jann10, is ideal for LPS extraction.

We describe a modified hot aqueous-phenol extraction method for purifying lipopolysaccharide (LPS) from Gram-negative bacteria. Once extracted, the LPS can be subsequently analyzed by SDS-PAGE and visualized by direct staining or Western immunoblot.

Lipopolysaccharide (LPS)  is a major component of Gram-negative bacterial outer membranes. It is a tripartite molecule consisting of  lipid A, which is ...

Establishment of an In vitro System to Study Intracellular Behavior of Candida glabrata in Human THP-1 Macrophages

A cell culture model system, if a close mimic of host environmental conditions, can serve as an inexpensive, reproducible and easily manipulatable alternative to animal model systems for the study of a specific step of microbial pathogen infection. A human monocytic cell line THP-1 which, upon phorbol ester treatment, is differentiated into macrophages, has previously been used to study virulence strategies of many intracellular pathogens including Mycobacterium tuberculosis. Here, we discuss a protocol to enact an in vitro cell culture model system using THP-1 macrophages to delineate the interaction of an opportunistic human yeast pathogen Candida glabrata with host phagocytic cells. This model system is simple, fast, amenable to high-throughput mutant screens, and requires no sophisticated equipment. A typical THP-1 macrophage infection experiment takes approximately 24 hr with an additional 24-48 hr to allow recovered intracellular yeast to grow on rich medium for colony forming unit-based viability analysis. Like other in vitro model systems, a possible limitation of this approach is difficulty in extrapolating the results obtained to a highly complex immune cell circuitry existing in the human host. However, despite this, the current protocol is very useful to elucidate the strategies that a fungal pathogen may employ to evade/counteract antimicrobial response and survive, adapt, and proliferate in the nutrient-poor environment of host immune cells.

Establishment of an In vitro System to Study Intracellular Behavior of Candida glabrata in Human THP-1 Macrophages

The current article outlines a protocol to establish an in vitro cell culture model system to study the interaction of a facultative intracellular human fungal pathogen Candida glabrata with human macrophages which will be a useful tool to advance our knowledge of fungal virulence mechanisms.

A cell culture model system, if a close mimic of host environmental conditions, can serve as an inexpensive, reproducible and easily manipulatable ...

Application of Fluorescent Nanoparticles to Study Remodeling of the Endo-lysosomal System by Intracellular Bacteria

Fluorescent nanoparticles (NPs) with desirable chemical, optical and mechanical properties are promising tools to label intracellular organelles. Here, we introduce a method using gold-BSA-rhodamine NPs to label the endo-lysosomal system of eukaryotic cells and monitor manipulations of host cellular pathways by the intracellular pathogen Salmonella enterica. The NPs were readily internalized by HeLa cells and localized in late endosomes/lysosomes. Salmonella infection induced rearrangement of the vesicles and accumulation of NPs in Salmonella-induced membrane structures. We deployed the Imaris software package for quantitative analyses of confocal microscopy images. The number of objects and their size distribution in non-infected cells were distinct from the ones in Salmonella-infected cells, indicating extremely remodeling of the endo-lysosomal system by WT Salmonella.

This article describes methods for the synthesis and fluorescent labeling of nanoparticles (NPs). The NPs were applied in pulse-chase experiments to label the endo-lysosomal system of eukaryotic cells. Manipulation of the endo-lysosomal system by activities of the intracellular pathogen Salmonella enterica were followed by live cell imaging and quantified.

Fluorescent nanoparticles (NPs) with desirable chemical, optical and mechanical properties are promising tools to label intracellular organelles. Here, we ...

Development of an in vitro model system for studying the interaction of Equus caballus IgE with its high-affinity receptor Fc&#949;RI

The interaction of IgE with its high-affinity Fc receptor (Fc&#949;RI) followed by an antigenic challenge is the principal pathway in IgE mediated allergic reactions. As a consequence of the high affinity binding between IgE and Fc&#949;RI, along with the continuous production of IgE by B cells, allergies usually persist throughout life, with currently no permanent cure available. Horses, especially race horses, which are commonly inbred, are a species of mammals that are very prone to the development of hypersensitivity responses, which can seriously affect their performance. Physiological responses to allergic sensitization in horses mirror that observed in humans and dogs. In this paper we describe the development of an in situ assay system for the quantitative assessment of the release of mediators of the allergic response pertaining to the equine system. To this end, the gene encoding equine Fc&#949;RI&#945; was transfected into and expressed onto the surface of parental Rat Basophil Leukemia (RBL-2H3.1) cells. The gene product of the transfected equine &#945;-chain formed a functional receptor complex with the endogenous rat &#946;- and &#947;-chains 1. The resultant assay system facilitated an assessment of the quantity of mediator secreted from equine Fc&#949;RI&#945; transfected RBL-2H3.1 cells following sensitization with equine IgE and antigenic challenge using &#946;-hexosaminidase release as a readout 2, 3. Mediator release peaked at 36.68% &#177; 4.88% at 100 ng ml-1 of antigen. This assay was modified from previous assays used to study human and canine allergic responses 4, 5. We have also shown that this type of assay system has multiple applications for the development of diagnostic tools and the safety assessment of potential therapeutic intervention strategies in allergic disease 6, 2, 3.

Development of an &lt;em&gt;in vitro&lt;/em&gt; model system for studying the interaction of &lt;em&gt;Equus&lt;/em&gt; &lt;em&gt;caballus&lt;/em&gt; IgE with its high-affinity receptor Fc&amp;#949;RI

The current study describes the development and applications of a genetically engineered assay system based on the transfection of rat basophilic leukemia cells with the equine Fc&#949;RI&#945; gene. Transfected cells express a functional receptor where the release of mediators of the allergic response can be activated by IgE and antigen.

The interaction of IgE with its high-affinity Fc receptor (Fc&#949;RI) followed by an antigenic challenge is the principal pathway in IgE mediated ...

The Mesenteric Lymph Duct Cannulated Rat Model: Application to the Assessment of Intestinal Lymphatic Drug Transport

The intestinal lymphatic system plays key roles in fluid transport, lipid absorption and immune function. Lymph flows directly from the small intestine via a series of lymphatic vessels and nodes that converge at the superior mesenteric lymph duct. Cannulation of the mesenteric lymph duct thus enables the collection of mesenteric lymph flowing from the intestine. Mesenteric lymph consists of a cellular fraction of immune cells (99% lymphocytes), aqueous fraction (fluid, peptides and proteins such as cytokines and gut hormones) and lipoprotein fraction (lipids, lipophilic molecules and apo-proteins). The mesenteric lymph duct cannulation model can therefore be used to measure the concentration and rate of transport of a range of factors from the intestine via the lymphatic system. Changes to these factors in response to different challenges (e.g., diets, antigens, drugs) and in disease (e.g., inflammatory bowel disease, HIV, diabetes) can also be determined. An area of expanding interest is the role of lymphatic transport in the absorption of orally administered lipophilic drugs and prodrugs that associate with intestinal lipid absorption pathways. Here we describe, in detail, a mesenteric lymph duct cannulated rat model which enables evaluation of the rate and extent of lipid and drug transport via the lymphatic system for several hours following intestinal delivery. The method is easily adaptable to the measurement of other parameters in lymph. We provide detailed descriptions of the difficulties that may be encountered when establishing this complex surgical method, as well as representative data from failed and successful experiments to provide instruction on how to confirm experimental success and interpret the data obtained.

Here we describe a technique to cannulate the mesenteric lymph duct in rats which enables quantification of lipid and drug transport via the lymphatic system following intestinal delivery. The technique can be adapted to assess mesenteric lymph concentrations and/or transport of fluid, immune cells, peptides, proteins and lipophilic molecules.

The intestinal lymphatic system plays key roles in fluid transport, lipid absorption and immune function. Lymph flows directly from the small intestine ...

Cultivation of Heligmosomoides Polygyrus: An Immunomodulatory Nematode Parasite and its Secreted Products

Heligmosomoides polygyrus (formerly known as Nematospiroides dubius, and also referred to by some as H. bakeri) is a gastrointestinal helminth that employs multiple immunomodulatory mechanisms to establish chronic infection in mice and closely resembles prevalent human helminth infections. H. polygyrus has been studied extensively in the field of helminth-derived immune regulation and has been found to potently suppress experimental models of allergy and autoimmunity (both with active infection and isolated secreted products). The protocol described in this paper outlines management of the H. polygyrus life cycle for consistent production of L3 larvae, recovery of adult parasites, and collection of their excretory-secretory products (HES).

Cultivation of Heligmosomoides Polygyrus: An Immunomodulatory Nematode Parasite and its Secreted Products

Heligmosomoides polygyrus is a murine nematode with powerful immunomodulatory capabilities that closely resemble those of highly-prevalent human helminth infection. Here we describe a protocol for the long-term maintenance of the H. polygyrus lifecycle.

Heligmosomoides polygyrus (formerly known as Nematospiroides dubius, and also referred to by some as H. bakeri) is a gastrointestinal helminth that ...

Development of an Antigen-driven Colitis Model to Study Presentation of Antigens by Antigen Presenting Cells to T Cells

Inflammatory bowel disease (IBD) is a chronic inflammation which affects the gastrointestinal tract (GIT). One of the best ways to study the immunological mechanisms involved during the disease is the T cell transfer model of colitis. In this model, immunodeficient mice (RAG-/- recipients) are reconstituted with naive CD4+ T cells from healthy wild type hosts.
This model allows examination of the earliest immunological events leading to disease and chronic inflammation, when the gut inflammation perpetuates but does not depend on a defined antigen. To study the potential role of antigen presenting cells (APCs) in the disease process, it is helpful to have an antigen-driven disease model, in which a defined commensal-derived antigen leads to colitis. An antigen driven-colitis model has hence been developed. In this model OT-II CD4+ T cells, that can recognize only specific epitopes in the OVA protein, are transferred into RAG-/- hosts challenged with CFP-OVA-expressing E. coli. This model allows the examination of interactions between APCs and T cells in the lamina propria.

In this antigen-driven colitis model, OT-II CD4+ T cells expressing a red fluorescent protein were adoptively transferred into RAG-/- mice that express a green fluorescent protein in mononuclear phagocytes (MPs). The hosts were challenged with Escherichia coli (E.coli) expressing the ovalbumin protein (OVA) fused to a cyan fluorescent protein (CFP).

Inflammatory bowel disease (IBD) is a chronic inflammation which affects the gastrointestinal tract (GIT). One of the best ways to study the immunological ...