We thank the Life Alliance Organ Recovery Agency of the University of Miami for providing lungs. We also thank Dr. Lisa K&#252;nzi for the DNA preparation used for the experiments shown in Figure 2B and 3-D, Dr. Ben Gerovac and Lisa Novak for the mCherry virus used for the experiments in Figures 3A to C. We also thank Gabriel Gaidosh from the imaging facility, Department of Ophthalmology at the University of Miami.
This study has been sponsored by grants from the NIH, the CF Foundation and the Flight Attendant Medical Research Institute to Dr. Matthias Salathe.

1. Stage 1: Culture of HEK 293T
<ol>
	<li>Prepare HEK cells media (referred as HEK media) by adding 10% (v/v) fetal bovine serum (FBS) and 1% (v/v) penicillin/streptomycin to high glucose Dulbecco&#39;s Modified Eagle&#39;s Medium (DMEM).</li>
	<li>Coat one 10 cm tissue culture dish with collagen I. Mix 30 &#181;l of collagen I in 2 ml of distilled water. Spread the mix onto the dish and incubate for 2 hr at 37 &#176;C and 5% CO2.</li>
	<li>Remove the mix and let the dish dry in a laminar flow cabinet for 15 min.</li>
	<li>Plate HEK cells onto the coated dish at a density of 1 x 106 cells in 10 ml HEK media and incubate at 37 &#176;C and 5% CO2.</li>
	<li>When HEK cells are 50-60% confluent (Figure 1a, 2-3 days after plating), proceed to stage 2. Visual assessment of confluency is sufficient. No quantification is needed. 
	Note: HEK cells are cultured in HEK media (see above). When they reach confluency, they can be split (e.g. 1/5) or frozen down for later use.</li>
</ol>
2. Stage 2: Production and Concentration of Lentiviruses (LVs) in HEK Cells
Note: The protocols should be executed in line with institutional and governmental regulations under BSL-2+ (enhanced BSL-2) conditions in the USA.
<ol>
	<li>Transfect using a calcium precipitation procedure (lipofectamine and other transfection agents were not as efficient as the calcium precipitation procedure). Use of a commercial transfection kit is recommended to assure reproducibility, though the procedure is modified as follows. Bring all reagents to room temperature. This is day 0.</li>
	<li>For each 10 cm dish of HEK293 cells, mix 4.5 &#181;g of envelope DNA pMD2-VSVG, 7.5 &#181;g packaging DNA pMDLg/pRRE, 3.75 &#181;g DNA pRSV-rev, 10 &#181;g DNA of lentiviral expression vector, 86 &#181;l of a 2 M calcium solution, and sterile water in a 15 ml centrifuge tube to a final volume of 700 &#181;l (the latter two solutions are provided in the commercial transfection kit).</li>
	<li>Drop-wise, add 700 &#181;l of 2x HEPES-buffered saline (HBS, provided in the transfection kit) while vortexing (in the laminar flow cabinet) and incubate at room temperature for 30 min (perform step 4 while waiting).</li>
	<li>During the early incubation time, deposit 5 &#181;l of the mix on a slide. Check the droplet under a microscope with a 10X objective, focusing slowly up and down. A fine precipitate should be visible, confirming the calcium phosphate precipitation process (Figure 1b).</li>
	<li>Stop the precipitation after 30 min by adding 10 ml of HEK cells media and pipette up and down to mix.</li>
	<li>Take the dish of HEK cells from step 2.1-2.5, and remove the medium (day 0). Add the precipitate solution from step 2.5 carefully and slowly along the edge of the dish.</li>
	<li>On the next day (day 1), remove and discard the medium containing the precipitate and replace it with 10 ml of HEK medium. Check for the fine precipitate under the microscope: it should be visible in the dish in empty spaces between the cells (Figures 1c and d).</li>
	<li>On day 2, collect media with a syringe, filter through a 0.45 &#181;m syringe filter into a 15 ml centrifuge tube containing 3.8 ml of a 40% polyethylene glycol (PEG) solution. Invert 5x to mix and store at 4 &#176;C for at least 24 hr (for the PEG precipitate to form, but no longer than 5 days) until all of the virus collections are complete.</li>
	<li>Repeat step 2.8 on days 3 and 4. On day 4 do not replace with HEK medium but decontaminate with 10% bleach and discard the dish.</li>
	<li>Centrifuge all the collection tubes (usually all collections together on day 5) at 1,650 x g for 20 min at 4 &#176;C to pellet the virus. Remove and discard the supernatant, and spin again at 1,650 x g for 5 min at 4 &#176;C to collect and remove any remaining of PEG supernatant.</li>
	<li>Resuspend the pellet of each tube in 200 &#181;l of bronchial epithelial growth medium (BEGM) without amphotericin B 8. Pool them together and aliquot at 200 &#181;l. Store virus at -80 &#176;C. Aliquot an additional 10 &#181;l to perform the HIV-1 Gag (p24) antigen ELISA assay.</li>
	<li>Using a commercial ELISA kit, perform a p24 antigen assay according to manufacturer&#39;s protocol. The assay gives an estimate of viral p24 in pg/ml.</li>
</ol>
3. Stage 3: Culture Primary HBE Cells
<ol>
	<li>Plate HBE cells in 10 ml BEGM media (with 100 &#181;l amphotericin B if passage 0 cells are used to eliminate possible fungal contamination) at a density of 1 x 106 cells in a collagen I coated 10 cm tissue culture dish. Incubate at 37 &#176;C and 5% CO2.</li>
	<li>On the next day, remove the medium and replace with 10 ml BEGM (with 100 &#181;l amphotericin B for passage 0 cells) for a total of 4 days. Return to incubator.</li>
	<li>After 4 days, use only BEGM without amphotericin B. Change media every other day.</li>
	<li>When cells are 80-90% confluent (Figure 2a; ~7 days after plating), proceed with transduction (pay attention to 3.5 for preparation before transduction). Again, visual assessment of confluency is sufficient. No quantification is needed.</li>
	<li>Prior to transduction, coat the permeable support inserts with a collagen IV solution diluted 1/10 with sterile distilled water. Add 200 &#181;l to each insert and let dry overnight in the laminar flow cabinet.</li>
</ol>
4. Stage 4: Transduction of HBE Cells
<ol>
	<li>Remove media, add 3 ml of 0.1% trypsin in 1 mM ethylenediaminetetraacetic acid in phosphate buffered saline (EDTA/PBS) and incubate 5 min at 37 &#176;C and 5% CO2. Check under the microscope (10X objective) to see if all the cells are detached. If not, return to the incubator for an additional 5 min.</li>
	<li>When all cells are detached, add 3 ml of soybean trypsin inhibitor (SBTI 1 mg/ml), mix and transfer to a 15 ml centrifuge tube. Pellet the cells by spinning at 460 x g for 5 min at room temperature.</li>
	<li>Remove supernatant and resuspend pellet into 3 ml of BEGM and proceed with counting.</li>
	<li>Resuspend HBE cells (now passage 1 or P1) at a ratio of 2 x 105 cells per one 12 mm permeable support insert in 400 &#181;l of BEGM (see Table 2). Extrapolate these numbers based on the amount of permeable support inserts that will be transduced.</li>
</ol>
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Surface</td>
			<td>Surface area</td>
			<td>Cell count</td>
			<td>Media</td>
			<td>Volume (media)</td>
		</tr>
		<tr>
			<td>10 cm dish</td>
			<td>52.7 cm2</td>
			<td>1 x 106</td>
			<td>BEGM</td>
			<td>10 ml</td>
		</tr>
		<tr>
			<td>12 mm filter</td>
			<td>1.13 cm2</td>
			<td>2 x 105</td>
			<td>BEGM</td>
			<td>400 &#956;l</td>
		</tr>
		<tr>
			<td>24 mm filter</td>
			<td>4.52 cm2</td>
			<td>8 x 105</td>
			<td>BEGM</td>
			<td>800 &#956;l</td>
		</tr>
	</tbody>
</table>
Table 2: Media extrapolation per cell count.
<ol start="5">
	<li>Using a multiplicity of infection (MOI) factor of 4, add the appropriate volume of virus to the cell suspension.</li>
	<li>Add hexadimethrine bromide to a 2 &#181;g/ml final concentration.</li>
	<li>Dispense 400 &#181;l of the mix (BEGM, HBE cells, virus and hexadimethrine bromide) per permeable support insert into the apical compartment, and add 1 ml of BEGM alone to the basolateral compartment. Incubate overnight at 37 &#176;C and 5% CO2. Always plate HBE cells without virus as control and test puromycin selection if applicable.</li>
	<li>On the next day, remove apical and basolateral media, wash with PBS, and replace both compartments with air-liquid interface (ALI) media 8.</li>
	<li>When cells are confluent, remove apical fluid (known as establishing an air-liquid interface). Continue changing the medium (ALI) in the bottom compartment every other day until they reach full maturity; usually 3 to 4 weeks later. 
	Note: If the lentiviral vector contains a selection gene such as puromycin, cells can be selected by adding puromycin according to a selection concentration curve. For HBE cells, a concentration of 1 &#181;g/ml has been determined to be ideal for consistent selection of transduced cells. However, this concentration might differ for other cells or conditions and should be determined by killing curves. Addition of puromycin can start as early as one day after the media has been replaced by ALI media or later (2-3 days) to allow the full expression of the selection gene. Be sure to add puromycin to one insert that has not been transduced. Puromycin can be added until the cells are fully differentiated.</li>
</ol>

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The authors have nothing to disclose.

The protocol outlined here assures close to 100% transduction efficiencies. However, there are steps during the process that are important to achieve this goal. For instance, during the transfection process, the presence of precipitates in the transduction mix (drop) or in the dish the day after transduction (Figures 1b and d) are both relevant for a good transfection. The absence of a precipitate or the presence of agglomerates can be due to an omission of one of the transfection reagen...

The development of replication-defective, pseudotyped lentiviruses (LV) has provided researchers with a safe and efficient method to deliver transgenes in vitro 1. Due to their long-term expression, these LV could also be used for the delivery of therapeutic agents in vivo 2,3. The production of LV requires co-transfection of human embryonic kidney (HEK) cells with several plasmids: transfer vector, packaging gag/pol, packaging rev, and envelope vesicular stomatitis virus glycoprotein (VSV-G) plasmids. Third-generation packaging systems are considered safer than second-generation systems because the rev gene is encoded on a separate packaging plasmid, thereby reducing the possibility of recombination to produce a replication competent lentivirus. Although second generation packaging systems yield five fold higher total transduction units, the split of the original viral genome to create the third generation system has decreased the level of transduction only minimally 3,4.
While cell lines can be transduced more easily and efficiently, researchers have shifted their focus to primary cells, because these are more representative of in vivo tissues 5,6. However, primary cells are refractory to transduction. While transduction of fully differentiated airway epithelial cells have been reported, the overall efficiency has not exceeded 15% 7.
Described here is a protocol that allows production of high-titer LVs. A step-by-step approach is outlined to achieve almost 100% transduction efficiency into primary HBE cells. More specifically, the protocol describes the optimal culture conditions instrumental to succeed 3. Briefly, HEK 293T cells are transfected using the lentiviral expression vector pCDH with the EF-1 promoter driving expression of enhanced green fluorescent protein (eGFP) or mCherry, a red fluorescent protein, and a third-generation packaging system. LVs released into the media are collected 24 to 72 hr later. The virus particles are concentrated with polyethylene glycol (PEG), a convenient and easy method of viral concentration, before titer estimation using a p24 antigen enzyme-linked immunosorbent assay (ELISA) kit. Subsequently, undifferentiated primary HBE cells are transduced in proliferation media (bronchial epithelial growth medium or BEGM) 8, while attaching (after being trypsinized), at a multiplicity of infection (MOI) factor of 4, adding hexadimethrine bromide and incubating for 16 hr (overnight). The cells are then allowed to differentiate. Since the viral transgene is expressed long-term (using the appropriate promoter, see discussion), expression will be maintained throughout differentiation into a pseudostratified airway epithelium or can be induced (using an inducible promoter) after differentiation.
This protocol is of broad interest to researchers who want to use primary HBE cells instead of cell lines, and might be adaptable to other difficult to transduce cell types.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>HEK293T/17 cells</td>
			<td>ATCC</td>
			<td>CRL-11268</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)&#160;</td>
			<td>Sigma</td>
			<td>12306C</td>
			<td>use at 10%</td>
		</tr>
		<tr>
			<td>DMEM</td>
			<td>Thermo Scientific</td>
			<td>11995-040</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin (100x)</td>
			<td>Thermo Scientific</td>
			<td>15140-122</td>
			<td>use at 1x</td>
		</tr>
		<tr>
			<td>Collagen I</td>
			<td>BD Biosciences</td>
			<td>354231</td>
			<td>dilute 1:75 in distilled water</td>
		</tr>
		<tr>
			<td>Calphos</td>
			<td>Clontech</td>
			<td>631312</td>
			<td>Transfection kit containing 2M Calcium solution, 2X HEPES-Buffered solution (HBS) and sterile H2O</td>
		</tr>
		<tr>
			<td>Polythylene glycol 8000</td>
			<td>VWR scientific</td>
			<td>101108-210</td>
			<td>stock of 40%</td>
		</tr>
		<tr>
			<td>Amphotericin B</td>
			<td>Sigma</td>
			<td>A9528</td>
			<td>use at 1x</td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Sigma</td>
			<td>T4799</td>
			<td></td>
		</tr>
		<tr>
			<td>Soybean trypsin inhibitor</td>
			<td>Sigma</td>
			<td>T9128</td>
			<td></td>
		</tr>
		<tr>
			<td>Transwell 12mm</td>
			<td>Corning</td>
			<td>3460</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagen IV</td>
			<td>Sigma</td>
			<td>C7521</td>
			<td>dilute 1:10 in distilled water</td>
		</tr>
		<tr>
			<td>Hexadimethrine bromide</td>
			<td>Sigma</td>
			<td>H9268</td>
			<td>stock of 2mg/ml</td>
		</tr>
		<tr>
			<td>Puromycin (10.000x)</td>
			<td>Thermo Scientific</td>
			<td>A11138-03</td>
			<td>use at 1x</td>
		</tr>
		<tr>
			<td>Alliance HIV-1 p24 ELISA</td>
			<td>PerkinElmer</td>
			<td>NEK050001KT</td>
			<td></td>
		</tr>
		<tr>
			<td>F12</td>
			<td>Thermo Scientific</td>
			<td>11765-054</td>
			<td></td>
		</tr>
		<tr>
			<td>pCDH-EF1-MCS-IRES-Puro</td>
			<td>System Biosciences</td>
			<td>CD532A-2</td>
			<td>lentiviral expression vector</td>
		</tr>
		<tr>
			<td>pMD2-VSVG</td>
			<td>Addgene</td>
			<td>12259</td>
			<td>packaging DNA</td>
		</tr>
		<tr>
			<td>pMDLg/pRRE</td>
			<td>Addgene</td>
			<td>12251</td>
			<td>packaging DNA</td>
		</tr>
		<tr>
			<td>pRSV-rev</td>
			<td>Addgene</td>
			<td>12253</td>
			<td>packaging DNA</td>
		</tr>
	</tbody>
</table>

optimal lentivirus production and cell culture conditions necessary to successfully transduce primary human bronchial epithelial cells

In vitro culture of primary human bronchial epithelial (HBE) cells using air-liquid interface conditions provides a useful model to study the processes of airway cell differentiation and function. In the past few years, the use of lentiviral vectors for transgene delivery became common practice. While there are reports of transduction of fully differentiated airway epithelial cells with certain non-HIV pseudo-typed lentiviruses, the overall transduction efficiency is usually less than 15%. The protocol presented here provides a reliable and efficient method to produce lentiviruses and to transduce primary human bronchial epithelial cells. Using undifferentiated bronchial epithelial cells, transduction in bronchial epithelial growth media, while the cells attach, with a multiplicity of infection factor of 4 provides efficiencies close to 100%. This protocol describes, step-by-step, the preparation and concentration of high-titer lentiviral vectors and the transduction process. It discusses the experiments that determined the optimal culture conditions to achieve highly efficient transductions of primary human bronchial epithelial cells.

Figure 1 depicts different key steps of assessing cells and solutions during the transfection process. Figure 1a shows the optimal confluency of HEK293T cells prior to transfection for virus production. It is important that the cells are distributed evenly throughout the dish. Figure 1b reveals the precipitate in a drop of the transfection mixture using bright field optics and a 10X objective. The more the precipitates look like sand grai...

Watch this Scientific Journal Video about Optimal Lentivirus Production and Cell Culture Conditions Necessary to Successfully Transduce Primary Human Bronchial Epithelial Cells at JoVE.com

Optimal Lentivirus Production and Cell Culture Conditions Necessary to Successfully Transduce Primary Human Bronchial Epithelial Cells

Primary human bronchial epithelial cells are difficult to transduce. This protocol describes the production of lentiviruses and their concentration as well as the optimal culture conditions necessary to achieve highly efficient transductions in these cells throughout differentiation to a pseudostratified epithelium.

In vitro culture of primary human bronchial epithelial (HBE) cells using air-liquid interface conditions provides a useful model to study the processes of ...

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19.2K Views.  University of Miami, Miller School of Medicine. Primary human bronchial epithelial cells are difficult to transduce. This protocol describes the production of lentiviruses and their concentration as well as the optimal culture conditions necessary to achieve highly efficient transductions in these cells throughout differentiation to a pseudostratified epithelium.

Video: Optimal Lentivirus Production and Cell Culture Conditions Necessary to Successfully Transduce Primary Human Bronchial Epithelial Cells

Human ES cells: Starting Culture from Frozen Cells

Here we demonstrate how our lab begins a HuES human embryonic stem cell line culture from a frozen stock.  First, a one to two day old ten cm plate of  approximately one (to two) million irradiated mouse embryonic fibroblast feeder cells is rinsed with HuES media to remove residual serum and cell debris, and then HuES media added and left to equilibrate in the cell culture incubator.  A frozen vial of cells from long term liquid nitrogen storage or a -80C freezer is sourced and quickly submerged in a 37C water bath for quick thawing.  Cells in freezing media are then removed from the vial and placed in a large volume of HuES media.  The large volume of HuES media facilitates removal of excess serum and DMSO, which can cause HuES human embryonic stem cells to differentiate.  Cells are gently spun out of suspension, and then re-suspended in a small volume of fresh HuES media that is then used to seed the MEF plate.  It is considered important to seed the MEF plate by gently adding the HuES cells in a drop wise fashion to evenly disperse them throughout the plate.  The newly established HuES culture plate is returned to the incubator for 48 hrs before media is replaced, then is fed every 24 hours thereafter.

Here we demonstrate how our lab begins a HuES human embryonic stem cell line culture from a frozen stock.

Here we demonstrate how our lab begins a HuES human embryonic stem cell line culture from a frozen stock.  First, a one to two day old ten cm plate of  ...

Lentivirus Production

RNA interference (RNAi) is a system of gene silencing in living cells. In RNAi, genes homologous in sequence to short interfering RNAs (siRNA) are silenced at the post-transcriptional state. Short hairpin RNAs, precursors to siRNA, can be expressed using lentivirus, allowing for RNAi in a variety of cell types. Lentiviruses, such as the Human Immunodeficiency Virus, are capable to infecting both dividing and non-dividing cells. We will describe a procedure which to package lentiviruses. Packaging refers to the preparation of competent virus from DNA vectors. Lentiviral vector production systems are based on a 'split' system, where the natural viral genome has been split into individual helper plasmid constructs. This splitting of the different viral elements into four separate vectors diminishes the risk of creating a replication-capable virus by adventitious recombination of the lentiviral genome. Here, a vector containing the shRNA of interest and three packaging vectors (p-VSVG, pRSV, pMDL) are transiently transfected into human 293 cells. After at least a 48-hour incubation period, the virus containing supernatant is harvested and concentrated. Finally, virus titer is determined by reporter (fluorescent) expression with a flow cytometer.

To make lentiviruses, DNA vectors are transfected into human 293 cells. After harvest and concentrating the supernatant, virus titer is determined by fluorescence expression with a flow cytometer.

RNA interference (RNAi) is a system of gene silencing in living cells. In RNAi, genes homologous in sequence to short interfering RNAs (siRNA) are ...

Primary Human Bronchial Epithelial Cells Grown from Explants

Human bronchial epithelial cells are needed for cell models of disease and to investigate the effect of excipients and pharmacologic agents on the function and structure of human epithelial cells. Here we describe in detail the method of growing bronchial epithelial cells from bronchial airway tissue that is harvested by the surgeon at the times of lung surgery (e.g. lung cancer or lung volume reduction surgery). With ethics approval and informed consent, the surgeon takes what is needed for pathology and provides us with a bronchial portion that is remote from the diseased areas. The tissue is then used as a source of explants that can be used for growing primary bronchial epithelial cells in culture. Bronchial segments about 0.5-1cm long and &le;1cm in diameter are rinsed with cold EBSS and excess parenchymal tissue is removed. Segments are cut open and minced into 2-3mm3 pieces of tissue. The pieces are used as a source of primary cells. After coating 100mm culture plates for 1-2 hr with a combination of collagen (30 &mu;g/ml), fibronectin (10 &mu;g/ml), and BSA (10 &mu;g/ml), the plates are scratched in 4-5 areas and tissue pieces are placed in the scratched areas, then culture medium (DMEM/Ham F-12 with additives) suitable for epithelial cell growth is added and plates are placed in an incubator at 37&deg;C in 5% CO2 humidified air. The culture medium is changed every 3-4 days. The epithelial cells grow from the pieces forming about 1.5 cm diameter rings in 3-4 weeks. Explants can be re-used up to 6 times by moving them into new pre-coated plates. Cells are lifted using trypsin/EDTA, pooled, counted, and re-plated in T75 Cell Bind flasks to increase their numbers. T75 flasks seeded with 2-3 million cells grow to 80% confluence in 4 weeks. Expanded primary human epithelial cells can be cultured and allowed to differentiate on air-liquid interface. Methods described here provide an abundant source of human bronchial epithelial cells from freshly isolated tissues and allow for studying these cells as models of disease and for pharmacology and toxicology screening.

Here we describe a detailed method for growing primary human bronchial epithelial cells from explants of human bronchial airway tissue including differentiated growth on an air-liquid interface. This method provides an abundant source of primary cells for investigating the role of the airway epithelium in human lung health and disease.

Human bronchial epithelial cells are needed for cell models of disease and to investigate the effect of excipients and pharmacologic agents on the ...

Isolation and Culture of Adult Epithelial Stem Cells from Human Skin

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate daughter cells that retain the stem cell phenotype and transit-amplifying cells (TA cells) that migrate from the stem cell niche, undergo rapid proliferation and terminally differentiate to repopulate the tissue.
Epithelial stem cells have been identified in the epidermis, hair follicle, and intestine as cells with a high in vitro proliferative potential and as slow-cycling label-retaining cells in vivo 1-3. Adult, tissue-specific stem cells are responsible for the regeneration of the tissues in which they reside during normal physiologic turnover as well as during times of stress 4-5. Moreover, stem cells are generally considered to be multi-potent, possessing the capacity to give rise to multiple cell types within the tissue 6. For example, rodent hair follicle stem cells can generate epidermis, sebaceous glands, and hair follicles 7-9. We have shown that stem cells from the human hair follicle bulge region exhibit multi-potentiality 10.
Stem cells have become a valuable tool in biomedical research, due to their utility as an in vitro system for studying developmental biology, differentiation, tumorigenesis and for their possible therapeutic utility. It is likely that adult epithelial stem cells will be useful in the treatment of diseases such as ectodermal dysplasias, monilethrix, Netherton syndrome, Menkes disease, hereditary epidermolysis bullosa and alopecias 11-13. Additionally, other skin problems such as burn wounds, chronic wounds and ulcers will benefit from stem cell related therapies 14,15. Given the potential for reprogramming of adult cells into a pluripotent state (iPS cells)16,17, the readily accessible and expandable adult stem cells in human skin may provide a valuable source of cells for induction and downstream therapy for a wide range of disease including diabetes and Parkinson's disease.

A rapid, robust way of isolating viable adult epithelial stem cells from human skin is described. The method utilizes enzymatic digestion of skin collagen matrix , followed by plucking of hair follicles and isolation of single cell suspensions or tissue fragments for cell culture.

The homeostasis of all self-renewing tissues is dependent on adult stem cells. As undifferentiated stem cells undergo asymmetric divisions, they generate ...

Ex Vivo Culture of Primary Human Fallopian Tube Epithelial Cells

Epithelial ovarian cancer is a leading cause of female cancer mortality in the United States. In contrast to other women-specific cancers, like breast and uterine carcinomas, where death rates have fallen in recent years, ovarian cancer cure rates have remained relatively unchanged over the past two decades 1. This is largely due to the lack of appropriate screening tools for detection of early stage disease where surgery and chemotherapy are most effective 2, 3. As a result, most patients present with advanced stage disease and diffuse abdominal involvement. This is further complicated by the fact that ovarian cancer is a heterogeneous disease with multiple histologic subtypes 4, 5. Serous ovarian carcinoma (SOC) is the most common and aggressive subtype and the form most often associated with mutations in the BRCA genes. Current experimental models in this field involve the use of cancer cell lines and mouse models to better understand the initiating genetic events and pathogenesis of disease 6, 7. Recently, the fallopian tube has emerged as a novel site for the origin of SOC, with the fallopian tube (FT) secretory epithelial cell (FTSEC) as the proposed cell of origin 8, 9. There are currently no cell lines or culture systems available to study the FT epithelium or the FTSEC. Here we describe a novel ex vivo culture system where primary human FT epithelial cells are cultured in a manner that preserves their architecture, polarity, immunophenotype, and response to physiologic and genotoxic stressors. This ex vivo model provides a useful tool for the study of SOC, allowing a better understanding of how tumors can arise from this tissue, and the mechanisms involved in tumor initiation and progression.

Ex Vivo Culture of Primary Human Fallopian Tube Epithelial Cells

The fallopian tube (FT) is emerging as an alternative site of origin for serous ovarian carcinoma (SOC). This protocol describes a novel method for the isolation and ex vivo culture of fallopian tube epithelial cells. This system recapitulates the in vivo epithelium and allows the study of SOC pathogenesis.

Epithelial ovarian cancer is a leading cause of female cancer mortality in the United States. In contrast to other women-specific cancers, like breast and ...

Transduction of Human Cells with Polymer-complexed Ecotropic Lentivirus for Enhanced Biosafety

Stem and tumor cell biology studies often require viral transduction of human cells with known or suspected oncogenes, raising major safety issues for laboratory personnel. Pantropic lentiviruses, such as the commonly used VSV-G pseudotype, are a valuable tool for studying gene function because they can transduce many cell types, including non-dividing cells. However, researchers may wish to avoid production and centrifugation of pantropic viruses encoding oncogenes due to higher biosafety level handling requirements and safety issues. Several potent oncogenes, including c-Myc and SV40 large T antigen, are known to enhance production of induced pluripotent stem cells (iPSC). All other known iPSC-inducing genetic changes (OCT4, SOX2, KLF4, NANOG, LIN28, and p53 loss of function) also have links to cancer, making them of relatively high safety concern as well. 
While these cancer-related viruses are useful in studying cellular reprogramming and pluripotency, they must be used safely. To address these biosafety issues, we demonstrate a method for transduction of human cells with ecotropic lentivirus, with additional emphasis on reduced cost and convenient handling. We have produced ecotropic lentivirus with sufficiently high titer to transduce greater than 90% of receptor-expressing human cells exposed to the virus, validating the efficacy of this approach. 
Lentivirus is often concentrated by ultracentrifugation; however, this process takes several hours and can produce aerosols infectious to human biomedical researchers. As an alternative, viral particles can be more safely sedimented onto cells by complexation with chondroitin sulfate and polybrene (CS/PB). This technique increases the functional viral titer up to 3-fold in cells stably expressing murine retrovirus receptor, with negligible added time and cost. Transduction of human dermal fibroblasts (HDFs) is maximally enhanced using CS/PB concentrations approximately 4-fold lower than the optimal value previously reported for cancer cell lines, suggesting that polymer concentration should be titrated for the target cell type of interest. We therefore describe the use of methylthiazolyldiphenyl-tetrazolium bromide (MTT) to assay for polymer toxicity in a new cell type. We observe equivalent viability of HDFs after viral transduction using either polymer complexation or the standard dose of polybrene (PB, 6 &mu;g/ml), indicating minimal acute toxicity.
In this protocol, we describe the use of ecotropic lentivirus for overexpression of oncogenes in human cells, reducing biosafety risks and increasing the transduction rate. We also demonstrate the use of polymer complexation to enhance transduction while avoiding aerosol-forming centrifugation of viral particles.

Lentiviruses are a valuable research tool for exploring gene function; however, researchers may wish to avoid production of pantropic lentivirus encoding known or suspected oncogenes. As an alternative, we present a safer protocol for use of ecotropic lentivirus on human cells modified to express the ecotropic receptor mSlc7a1.

Stem and tumor cell biology studies often require viral transduction of human cells with known or suspected oncogenes, raising major safety issues for ...

Induction and Analysis of Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is essential for proper morphogenesis during development. Misregulation of this process has been implicated as a key event in fibrosis and the progression of carcinomas to a metastatic state. Understanding the processes that underlie EMT is imperative for the early diagnosis and clinical control of these disease states. Reliable induction of EMT in vitro is a useful tool for drug discovery as well as to identify common gene expression signatures for diagnostic purposes. Here we demonstrate a straightforward method for the induction of EMT in a variety of cell types. Methods for the analysis of cells pre- and post-EMT induction by immunocytochemistry are also included. Additionally, we demonstrate the effectiveness of this method through antibody-based array analysis and migration/invasion assays.

A straightforward method is described for the induction of epithelial to mesenchymal transition (EMT) in a variety of cell types. Methods for the analysis of cells in EMT states by immunocytochemistry are included.

Epithelial  to mesenchymal transition (EMT) is essential for proper morphogenesis during  development. Misregulation of this  process has been implicated ...

Primary Culture of Rat Adrenocortical Cells and Assays of Steroidogenic Functions

The hormone which the adrenal cortex secretes is vital for animals against stress and diseases. The method described here is the procedure of primary cultured rat adrenal cells and related functional assays (immunofluorescence staining of lipid droplet surface protein, as well as corticosterone analysis). Unlike an in vivo model, the variation of interexperiments in adrenal monolayer cultures is less and the experimental condition is easy to control. Besides, the source of rats is also more stable than other animals, like bovine ones. There are also several human adrenal cell lines (NCI-H295, NCI-H295R, SW13, etc.) that can be used in adrenal studies. However, the steroid production of these lines will still be influenced by numerous factors, which include serum lot number, passage number, mutant/loss of distinct genes, etc. Except for lacking 17&#945;-hydroxylase, the primary culture of rat adrenocortical cells is a better and more convenient technique for studying adrenal physiology. In summary, primary rat adrenal cultures could be a good in vitro platform for researchers to investigate the mechanisms of the reagent of interest in the adrenal gland system.

The hormone secreted by the adrenal cortex is vital for animals against stress and diseases. Here, we present a protocol to culture the primary rat adrenal cells. It could be a good in vitro platform for investigating the mechanisms of the reagent of interest in adrenal steroidogenesis and lipid biosynthesis.

The hormone which the adrenal cortex secretes is vital for animals against stress and diseases. The method described here is the procedure of primary ...

Multicellular Human Alveolar Model Composed of Epithelial Cells and Primary Immune Cells for Hazard Assessment

A human alveolar cell coculture model is described here for simulation of the alveolar epithelial tissue barrier composed of alveolar epithelial type II cells and two types of immune cells (i.e., human monocyte-derived macrophages [MDMs] and dendritic cells [MDDCs]). A protocol for assembling the multicellular model is provided. Alveolar epithelial cells (A549 cell line) are grown and differentiated under submerged conditions on permeable inserts in two-chamber wells, then combined with differentiated MDMs and MDDCs. Finally, the cells are exposed to an air-liquid interface for several days. As human primary immune cells need to be isolated from human buffy coats, immune cells differentiated from either fresh or thawed monocytes are compared in order to tailor the method based on experimental needs. The three-dimensional models, composed of alveolar cells with either freshly isolated or thawed monocyte-derived immune cells, show a statistically significant increase in cytokine (interleukins 6 and 8) release upon exposure to proinflammatory stimuli (lipopolysaccharide and tumor necrosis factor &#945;) compared to untreated cells. On the other hand, there is no statistically significant difference between the cytokine release observed in the cocultures. This shows that the presented model is responsive to proinflammatory stimuli in the presence of MDMs and MDDCs differentiated from fresh or thawed peripheral blood monocytes (PBMs). Thus, it is a powerful tool for investigations of acute biological response to different substances, including aerosolized drugs or nanomaterials.

Presented here is a protocol for primary human blood monocyte isolation as well as their differentiation into macrophages and dendritic cells and assembly with epithelial cells into a multicellular human lung model. Biological responses of cocultures composed of immune cells differentiated from either freshly isolated or thawed monocytes, upon exposure to proinflammatory stimuli, are compared.

A human alveolar cell coculture model is described here for simulation of the alveolar epithelial tissue barrier composed of alveolar epithelial type II ...

Isolation and Enrichment of Human Lung Epithelial Progenitor Cells for Organoid Culture

Epithelial organoid models serve as valuable tools to study the basic biology of an organ system and for disease modeling. When grown as organoids, epithelial progenitor cells can self-renew and generate differentiating progeny that exhibit cellular functions similar to those of their in vivo counterparts. Herein we describe a step-by-step protocol to isolate region-specific progenitors from human lung and generate 3D organoid cultures as an experimental and validation tool. We define proximal and distal regions of the lung with the goal of isolating region-specific progenitor cells. We utilized a combination of enzymatic and mechanical dissociation to isolate total cells from the lung and trachea. Specific progenitor cells were then fractionated from the proximal or distal origin cells using fluorescence associated cell sorting (FACS) based on cell type-specific surface markers, such as NGFR&#160;for sorting basal cells and HTII-280 for sorting alveolar type II cells. Isolated basal or alveolar type II progenitors were used to generate 3D organoid cultures. Both distal and proximal progenitors formed organoids with a colony forming efficiency of 9-13% in distal region and 7-10% in proximal region when plated 5000 cell/well on day 30. Distal organoids maintained HTII-280+ alveolar type II cells in culture whereas proximal organoids differentiated into ciliated and secretory cells by day 30. These 3D organoid cultures can be used as an experimental tool for studying the cell biology of lung epithelium and epithelial mesenchymal interactions, as well as for the development and validation of therapeutic strategies targeting epithelial dysfunction in a disease.

This article provides a detailed methodology for tissue dissociation and cellular fractionation approaches allowing enrichment of viable epithelial cells from proximal and distal regions of the human lung. Herein these approaches are applied for the functional analysis of lung epithelial progenitor cells through the use of 3D organoids culture models.

Epithelial organoid models serve as valuable tools to study the basic biology of an organ system and for disease modeling. When grown as organoids, ...