This work was supported by NIH K99 HL09222601 and the S&amp;R Foundation Ryaji Uneo Award awarded to MNH.

1. Anesthesia
<ol>
<li> Anesthetizing mice with isoflurane may facilitate animal handling and restraint prior to administering anesthesia intraperitaneally. Using an inhaled anesthetic may or may not be suitable for a particular study: determine first the impact of using isoflurane, or any other anesthetic, on proposed lung study.</li>
<li> Anesthetize animals with isoflurane. The video shows the use of an isoflurane vaporizer chamber set at 2% isoflurane mixed with oxygen. If you do not have an isoflurane chamber, you can alternatively using standard open-drop exposure techniques. Enclose rats in a bell jar (or other appropriate non-porous container) with a wire mesh fitted to the bottom. To a gauze pad placed beneath the mesh wire, apply a mixture of 30% v/v isoflurane in propylene glycol. The use of the mesh ensures that the animal does not come into contact with the isoflurane-soaked pad, which could cause skin irritation and potential overdosing. After short exposure to isoflurane, the animal should be anesthetized and will not respond with a righting reflex when the jar is tipped and will not respond after toe pinch.</li>
 <li>Further sedate mice with an intra-peritoneal injection of a mix of Xylazine and Ketamine. (It is good practice when performing intraperitoneal injections to draw back to insure that portions of the gut or other vital organs have not been penetrated). Mix 150 &mu;L Xylazine (100 mg/mL) with 1000 &mu;L Ketamine (100 mg/mL) in 8850 &mu;L of 0.9% sterile phosphate buffered saline (PBS). For mice, the dosage will be approximately 80 &mu;L per 10 gm of body weight. The final concentrations will be 10 mg/Kg Xylazine and 100 mg/Kg Ketamine. The animals should be kept dry and insulated to prevent excessive loss of body heat. Ophthalmic ointment can be applied to the eyes to prevent drying of the corneas.</li>
 </ol>
 2. Preparation of Surgical Area
 <ol>
<li>Shaving the area where the surgical incision will be made prevents contamination from non-prepped areas. An electric razor can closely shave the fur off the animal. The shaved area should be larger than the incision site.</li>
 <li>Subsequent application of hair removal cream, such as Nair, will remove all remaining fur. Apply a thick layer of hair removal cream to the surgical area and leave on for 3 minutes. Wipe away the fur and hair removal cream with a damp towel. Do not leave the hair removal cream on in excess of 10 minutes.</li>
 <li>Use 70% alcohol, or an alternative scrub solution, to aseptically prepare the surgical area.</li>
 </ol>
 3. Surgical Procedure
 <ol>
<li>Position the anesthetized animal onto a sloped surgical board, or angled restraining stand.</li>
<li>Make a small incision near the anterior aspect of the neck (throat region).</li>
<li>Dissect away the platysma and anterior tracheal muscles in order to visualize and access the tracheal rings.</li>
<li>Typically, intratracheal injection volumes are 3 &mu;l per gram of weight (approximately 30-75 &mu;L final volume). Administer the appropriate amount of instillate using a 1mL subcutaneous (sub-Q) syringe with a 30 gauge, 5/16-inch needle. Hold the syringe bevel side up and parallel with the trachea, and inject the full volume of instillate into the trachea.</li>
<li>The animal may respond by gasping following the instillation of solute into the lungs. Introducing air through the syringe and observing whether the lungs expand will also confirm successful intubation techniques.</li>
<li> Remove syringe from the trachea.</li>
</ol>
4. Sutures.
<ol>
<li>Grasp the needle's swage (thickest portion of the needle where the suture material is attached) with a needle holder.</li>
<li>Penetrate the skin with the tip of the needle at a 90&deg; angle approximately 1-3 mm away from the edge of the wound, depending on the thickness of the skin. Grasp the exiting needle after one pass through the tissue. Simple stitches, individually knotted, will efficiently close the wound.</li>
</ol>
5. Animal Recovery
<ol>
<li>Animals should fully recover from the anesthesia and surgical procedure after 3-24 hours.</li>
</ol>
6. Representative Results
Intratracheal instillation of fluorescent compound, Cy5.5 conjugated to dextran, shows successful instillation of fluorescent compound in B6 mouse lung (Figure 1). The fluorescent dye is primarily targeted to the lung and is evenly distributed. Fluorescent signal in the gastrointestinal tract immediately following the procedure indicates that the esophagus was inadvertently intubated during the procedure (Figure 2). Investigators may also verify targeted delivery of compounds into the lung, and check distribution of the instillate, following the procedure by inflating the lungs and preparing lung tissue slices (2; 3) or fixed histological samples.
<img src="/files/ftp_upload/1941/1941fig1.jpg" alt="Figure 1" /> Figure 1. Fluorescent Cy5.5 signal co-registered with X-ray image in successfully instilled mouse lung. 1.4 mg Cy5.5 Dextran (at a concentration of 10 &mu;g/&mu;L) was instilled into the trachea of B6 mouse lung. Cy5.5 signal was detected using a 675 nm excitation filter and a 695 nm emission filter.
<img src="/files/ftp_upload/1941/1941fig2.jpg" alt="Figure 2" /> Figure 2. Co-registration of fluorescent signal shown with X-ray overlay in poorly instilled mouse. Inappropriate intubation of the esophagus during tracheal instillation protocol results in Cy5.5 delivery to the intestines.

<ol>
	<li>Driscoll, K. E., Costa, D. L., Hatch, G., Henderson, R., Oberdorster, G., Salem, H., Schlesinger, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intratracheal+instillation+as+an+exposure+technique+for+the+evaluation+of+respiratory+tract+toxicity:+uses+and+limitations.">Intratracheal instillation as an exposure technique for the evaluation of respiratory tract toxicity: uses and limitations.</a> Toxicol Sci. 55, 24-35 (2000).</li><li>Helms, M. N., Jain, L., Self, J. L., Eaton, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Redox+regulation+of+epithelial+sodium+channels+examined+in+alveolar+type+1+and+2+cells+patch-clamped+in+lung+slice+tissue.">Redox regulation of epithelial sodium channels examined in alveolar type 1 and 2 cells patch-clamped in lung slice tissue.</a> J Biol Chem. 283, 22875-22883 (2008).</li><li>Helms, M. N., Self, J., Bao, H. F., Job, L. C., Jain, L., Eaton, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dopamine+activates+amiloride-sensitive+sodium+channels+in+alveolar+type+I+cells+in+lung+slice+preparations.">Dopamine activates amiloride-sensitive sodium channels in alveolar type I cells in lung slice preparations.</a> Am J Physiol Lung Cell Mol Physiol. 291, L610-L618 (2006).</li><li>Iyer, S. S., Ramirez, A. M., Ritzenthaler, J. D., Torres-Gonzalez, E., Roser-Page, S., Mora, A. L., Brigham, K. L., Jones, D. P., Roman, J., Rojas, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oxidation+of+extracellular+cysteine/cystine+redox+state+in+bleomycin-induced+lung+fibrosis.">Oxidation of extracellular cysteine/cystine redox state in bleomycin-induced lung fibrosis.</a> Am J Physiol Lung Cell Mol Physiol. 296, L37-L45 (2009).</li><li>Li, T., Folkesson, H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNA+interference+for+alpha-ENaC+inhibits+rat+lung+fluid+absorption+in+vivo.">RNA interference for alpha-ENaC inhibits rat lung fluid absorption in vivo.</a> Am J Physiol Lung Cell Mol Physiol. 290, L649-L660 (2006).</li><li>Sager, T., Porter, D., Robinson, V., Lindsley, W., Schwegler-Berry, D., Castranova, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+improved+method+to+disperse+nanoparticles+for+in+vitro+and+in+vivo+investigation+of+toxicity.">An improved method to disperse nanoparticles for in vitro and in vivo investigation of toxicity.</a> Nanotoxicol. 1, 118-129 (2007).</li><li>Xu, J., Gonzalez, E. T., Iyer, S. S., Mac, V., Mora, A. L., Sutliff, R. L., Reed, A., Brigham, K. L., Kelly, P., Rojas, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+senescence-accelerated+mouse+model+in+bleomycin-induced+lung+injury+suggests+that+bone+marrow-derived+cells+can+alter+the+outcome+of+lung+injury+in+aged+mice.">Use of senescence-accelerated mouse model in bleomycin-induced lung injury suggests that bone marrow-derived cells can alter the outcome of lung injury in aged mice.</a> J Gerontol A Biol Sci Med Sci. 64, 731-739 (2009).</li><li>Yeh, T. F., Lin, H. C., Chang, C. H., Wu, T. S., Su, B. H., Li, T. C., Pyati, S., Tsai, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+intratracheal+instillation+of+budesonide+using+surfactant+as+a+vehicle+to+prevent+chronic+lung+disease+in+preterm+infants:+a+pilot+study.">Early intratracheal instillation of budesonide using surfactant as a vehicle to prevent chronic lung disease in preterm infants: a pilot study.</a> Pediatrics. 121, e1310-e1318 (2008).</li></ol>

Intratracheal instillations have been used in several various studies to evaluate the toxicity of test compounds (6), induce alveolar lung injury (4; 7), replace surfactants (8), as well as alter gene expression via delivery of small oligonucleotides directly into the lung (5). We are currently exploring the use of instilling 1) fluorescent redox-sensitive material into the lung in order to measure oxidative stress in vivo under normal and pathophysiological conditions, as well as 2) instilling fluorescent indicators w...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
		<tbody>
		
<tr>
<td>Isoflurane	</td>
<td>&nbsp;</td>
<td>Webster Veterinary Sterling , MA</td>
<td>14043-220-05</td>
<td>&nbsp;</td>
<tr>
<td>Xylazine</td>
<td>&nbsp;</td>
<td>Lloyd Laboratories Shenandoah, IA</td>
<td>&nbsp;</td>
<td>New Animal Drug Application #139-236</td>
</tr>
<tr>
<td>Ketamine</td>
<td>&nbsp;</td>
<td>Bioniche Pharma Lake Forest, IL</td>
<td>67457-001-10</td>
<td>&nbsp;</td>
<tr>
<td>Nair</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>Available at drug stores</td>
</tr>
<tr>
<td>1mL SubQ Syringe</td>
<td>&nbsp;</td>
<td>BD Syringe Franklin Lakes, NJ</td>
<td>309597</td>
<td>26 5/8 G</td>
</tr>
<tr>
<td>4-0 Nylon Suture</td>
<td>&nbsp;</td>
<td>Ethicon San Lorenzo, Puerto Rico</td>
<td>1894G.S30</td>
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direct tracheal instillation of solutes into mouse lung

Intratracheal instillations deliver solutes directly into the lungs. This procedure targets the delivery of the instillate into the distal regions of the lung, and is therefore often incorporated in studies aimed at studying alveoli. We provide a detailed survival protocol for performing intratracheal instillations in mice. Using this approach, one can target delivery of test solutes or solids (such as lung therapeutics, surfactants, viruses, and small oligonucleotides) into the distal lung. Tracheal instillations may be the preferred methodology, over inhalation protocols that may primarily target the upper respiratory tract and possibly expose the investigator to potentially hazardous substances. Additionally, in using the tracheal instillation protocol, animals can fully recover from the non-invasive procedure. This allows for making subsequent physiological measurements on test animals, or reinstallation using the same animal. The amount of instillate introduced into the lung must be carefully determined and osmotically balanced to ensure animal recovery. Typically, 30-75 &mu;L instillate volume can be introduced into mouse lung.

Watch this Scientific Journal Video about Direct Tracheal Instillation of Solutes into Mouse Lung at JoVE.com

Direct Tracheal Instillation of Solutes into Mouse Lung

Intratracheal instillations deliver solutes directly into the lungs. This procedure targets the delivery of the instillate into the distal regions of the lung, and is therefore often incorporated in studies aimed at studying alveoli. We provide a detailed survival protocol for performing intratracheal instillations in mice.

Intratracheal instillations deliver solutes directly into the lungs.  This procedure targets the delivery of the instillate into the distal regions of the ...

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29.0K Views.  Emory University. Intratracheal instillations deliver solutes directly into the lungs. This procedure targets the delivery of the instillate into the distal regions of the lung, and is therefore often incorporated in studies aimed at studying alveoli. We provide a detailed survival protocol for performing intratracheal instillations in mice.

Video: Direct Tracheal Instillation of Solutes into Mouse Lung

Nuclear Transfer into Mouse Oocytes

Nuclear transfer into an unfertilized oocyte can restore developmental potential to a differentiated cell. This demonstrates that the processes underlying development, differentiation and aging are epigenetic rather than genetic processes. The reversibility of these processes opens exciting perspectives in basic research, and in the more distant future, in regenerative medicine. In the mouse, embryonic stem cells can be derived from cloned preimplantation stage embryos. Such embryonic stem cells have the ability to give rise to all cell types of the adult organism. Importantly, these cells are genetically identical to the donor. If applicable to human, this would allow the derivation of stem cells from a patient. These cells could then be differentiated into the affected cell type of the patient and studied in vitro, or used to replace the damaged or missing cells. The study of nuclear transfer in the mouse remains important as it can inform us about the principles of nuclear reprogramming. This movie and the accompanying protocol are intended to help learning nuclear transfer in the mouse, a method initially developed in the group of Prof. Yanagimachi (WAKAYAMA et al. 1998).

This movie and the protocol are intended to help learning nuclear transfer.

Nuclear transfer into an unfertilized oocyte can restore developmental potential to a differentiated cell. This demonstrates that the processes underlying ...

Mouse Embryonic Lung Culture, A System to Evaluate the Molecular Mechanisms of Branching

Lung primordial specification as well as branching morphogenesis, and the formation of various pulmonary cell lineages requires a specific interaction of the lung endoderm with its surrounding mesenchyme and mesothelium. Lung mesenchyme has been shown to be the source of inductive signals for lung branching morphogenesis. Epithelial-mesenchymal-mesothelial interactions are also critical to embryonic lung morphogenesis. Early embryonic lung organ culture is a very useful system to study epithelial-mesenchymal interactions. Both epithelial and mesenchymal morphogenesis proceeds under specific conditions that can be readily manipulated in this system (in the absence of maternal influence and blood flow). More importantly this technique can be readily done in a serumless, chemically defined culture media. Gain and loss of function can be achieved using expressed proteins, recombinant viral vectors and/or analysis of transgenic mouse strains, antisense RNA, as well as RNA interference gene knockdown.

Early embryonic lung organ culture is a very useful system to study epithelial-mesenchymal interactions. Both epithelial and mesenchymal morphogenesis proceeds under specific conditions that can be readily manipulated in this system.

Lung primordial specification as well as branching morphogenesis, and the formation of various pulmonary cell lineages requires a specific interaction of ...

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Human cancer and response to therapy is better represented in orthotopic animal models. This paper describes the development of an orthotopic mouse model of ovarian cancer, treatment of cancer via oral delivery of drugs, and monitoring of tumor cell behavior in response to drug treatment in real time using in vivo imaging system. In this orthotopic model, ovarian tumor cells expressing luciferase are applied topically by injecting them directly into the mouse bursa where each ovary is enclosed. Upon injection of D-luciferin, a substrate of firefly luciferase, luciferase-expressing cells generate bioluminescence signals. This signal is detected by the in vivo imaging system and allows for a non-invasive means of monitoring tumor growth, distribution, and regression in individual animals. Drug administration via oral gavage allows for a maximum dosing volume of 10 mL/kg body weight to be delivered directly to the stomach and closely resembles delivery of drugs in clinical treatments. Therefore, techniques described here, development of an orthotopic mouse model of ovarian cancer, oral delivery of drugs, and in vivo imaging, are useful for better understanding of human ovarian cancer and treatment and will improve targeting this disease.

In vivo Imaging and Therapeutic Treatments in an Orthotopic Mouse Model of Ovarian Cancer

Orthotopic animal models of ovarian cancer replicate better human disease and therefore enhance our understanding of cancer progression and tumor response to therapy. A mouse model receives an intrabursal injection of luciferase-expressing ovarian tumor cells. Treatment is administered via oral gavage. Tumor growth is monitored by in vivo imaging system.

Human cancer and response to therapy is better represented in orthotopic animal models.  This paper describes the development of an orthotopic mouse model ...

Direct Delivery of MIF Morpholinos Into the Zebrafish Otocyst by Injection and Electroporation Affects Inner Ear Development

In recent years, electroporation has become a popular technique for in vivo transfection of DNA, RNA, and morpholinos into various tissues, including the eye, brain, and somites of zebrafish. The advantage of electroporation over other methods of genetic manipulation is that specific tissues can be targeted, both spatially and temporally, for the introduction of macromolecules by the application of electrical current. Here we describe the use of electroporation for transfecting mif and mif-like morpholinos into the tissues of the developing inner ear of the zebrafish. In past studies, mif morpholino injected into embryos at the 1- to 8-cell stage resulted in widespread morphological changes in the nervous system and eye, as well as the ear. By targeting the tissues of the inner ear at later stages in development, we can determine the primary effects of MIF in the developing inner ear, as opposed to secondary effects that may result from the influence of other tissues. By using phalloidin and acetylated tubulin staining to study the morphology of neurons, neuronal processes, and hair cells associated with the posterior macula, we were able to assess the efficacy of electroporation as a method for targeted transfection in the zebrafish inner ear. The otic vesicles of 24hpf embryos were injected with morpholinos and electroporated and were then compared to embryos that had received no treatment or had been only injected or electroporated. Embryos that were injected and electroporated showed a decrease in hair cell numbers, decreased innervation by the statoacoustic ganglion (SAG) and fewer SAG neurons compared with control groups. Our results showed that direct delivery of morpholinos into otocysts at later stages avoids the non-specific nervous system and neural crest effects of morpholinos delivered at the 1-8 cell stage. It also allows examination of effects that are directed to the inner ear and not secondary effects on the ear from primary effects on the brain, neural crest or periotic mesenchyme.

A method to deliver morpholinos directly into the zebrafish otocyst at 24hpf has been developed. Using microinjection of morpholinos into the lumen of otic vesicle and electroporation to effect penetration, we were able to bypass the effect of morpholinos on the brain and obtain effects specific to the inner ear.

In recent years, electroporation has become a popular technique for in vivo transfection of DNA, RNA, and morpholinos into various tissues, including the ...

Characterization of the Isolated, Ventilated, and Instrumented Mouse Lung Perfused with Pulsatile Flow

The isolated, ventilated and instrumented mouse lung preparation allows steady and pulsatile pulmonary vascular pressure-flow relationships to be measured with independent control over pulmonary arterial flow rate, flow rate waveform, airway pressure and left atrial pressure. Pulmonary vascular resistance is calculated based on multi-point, steady pressure-flow curves; pulmonary vascular impedance is calculated from pulsatile pressure-flow curves obtained at a range of frequencies. As now recognized clinically, impedance is a superior measure of right ventricular afterload than resistance because it includes the effects of vascular compliance, which are not negligible, especially in the pulmonary circulation. Three important metrics of impedance - the zero hertz impedance Z0, the characteristic impedance ZC, and the index of wave reflection RW - provide insight into distal arterial cross-sectional area available for flow, proximal arterial stiffness and the upstream-downstream impedance mismatch, respectively. All results obtained in isolated, ventilated and perfused lungs are independent of sympathetic nervous system tone, volume status and the effects of anesthesia. We have used this technique to quantify the impact of pulmonary emboli and chronic hypoxia on resistance and impedance, and to differentiate between sites of action (i.e., proximal vs. distal) of vasoactive agents and disease using the pressure dependency of ZC. Furthermore, when these techniques are used with the lungs of genetically engineered strains of mice, the effects of molecular-level defects on pulmonary vascular structure and function can be determined.

The following protocol outlines the process of isolating, ventilating and instrumenting mouse lungs to measure steady or pulsatile pulmonary vascular pressure-flow relationships in order to quantify the effects of blood flow, airflow, airway changes and vascular changes on right ventricular afterload.

The isolated, ventilated and instrumented mouse lung preparation allows steady and pulsatile pulmonary vascular pressure-flow relationships to be measured ...

Isolation &#38; Characterization of Hoechstlow CD45negative Mouse Lung Mesenchymal Stem Cells

Tissue resident mesenchymal stem cells (MSC) are important regulators of tissue repair or regeneration, fibrosis, inflammation, angiogenesis and tumor formation. Taken together these studies suggest that resident lung MSC play a role during pulmonary tissue homeostasis, injury and repair during diseases such as pulmonary fibrosis (PF) and arterial hypertension (PAH). Here we describe a technology to define a population of resident lung MSC. The definition of this population in vivo pulmonary tissue using a define set of markers facilitates the repeated isolation of a well-characterized stem cell population by flow cytometry and the study of a specific cell type and function.

Isolation & Characterization of Hoechstlow CD45negative Mouse Lung Mesenchymal Stem Cells

In this article we demonstrate the isolation of murine resident lung mesenchymal stem cells (lung MSC), their expansion, characterization and analysis of immunomodulatory properties.

Tissue resident mesenchymal stem cells (MSC) are important regulators of tissue repair or regeneration, fibrosis, inflammation, angiogenesis and tumor ...

Efficient Differentiation of Mouse Embryonic Stem Cells into Motor Neurons

Direct differentiation of embryonic stem (ES) cells into functional motor neurons represents a promising resource to study disease mechanisms, to screen new drug compounds, and to develop new therapies for motor neuron diseases such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS). Many current protocols use a combination of retinoic acid (RA) and sonic hedgehog (Shh) to differentiate mouse embryonic stem (mES) cells into motor neurons1-4. However, the differentiation efficiency of mES cells into motor neurons has only met with moderate success. We have developed a two-step differentiation protocol5 that significantly improves the differentiation efficiency compared with currently established protocols. The first step is to enhance the neuralization process by adding Noggin and fibroblast growth factors (FGFs). Noggin is a bone morphogenetic protein (BMP) antagonist and is implicated in neural induction according to the default model of neurogenesis and results in the formation of anterior neural patterning6. FGF signaling acts synergistically with Noggin in inducing neural tissue formation by promoting a posterior neural identity7-9. In this step, mES cells were primed with Noggin, bFGF, and FGF-8 for two days to promote differentiation towards neural lineages. The second step is to induce motor neuron specification. Noggin/FGFs exposed mES cells were incubated with RA and a Shh agonist, Smoothened agonist (SAG), for another 5 days to facilitate motor neuron generation. To monitor the differentiation of mESs into motor neurons, we used an ES cell line derived from a transgenic mouse expressing eGFP under the control of the motor neuron specific promoter Hb91. Using this robust protocol, we achieved 51&plusmn;0.8% of differentiation efficiency (n = 3; p &lt; 0.01, Student's t-test)5. Results from immunofluorescent staining showed that GFP+ cells express the motor neuron specific markers, Islet-1 and choline acetyltransferase (ChAT). Our two-step differentiation protocol provides an efficient way to differentiate mES cells into spinal motor neurons.

We developed a new protocol to improve efficiency of in vitro differentiation of mouse embryonic stem cells into motor neurons. The differentiated ES cells acquired motor neurons features as evidenced by expression of neuronal and motor neuron markers using immunohistochemical techniques.

Direct differentiation of embryonic stem (ES) cells into functional  motor neurons represents a promising resource to study disease mechanisms, to  screen ...

Generation of Mice Derived from Induced Pluripotent Stem Cells

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also produce a source of patient-matched cells for regenerative therapies. iPSCs may be generated using multiple protocols and derived from multiple cell sources. Once generated, iPSCs are tested using a variety of assays including immunostaining for pluripotency markers, generation of three germ layers in embryoid bodies and teratomas, comparisons of gene expression with embryonic stem cells (ESCs) and production of chimeric mice with or without germline contribution2. Importantly, iPSC lines that pass these tests still vary in their capacity to produce different differentiated cell types2. This has made it difficult to establish which iPSC derivation protocols, donor cell sources or selection methods are most useful for different applications.
The most stringent test of whether a stem cell line has sufficient developmental potential to generate all tissues required for survival of an organism (termed full pluripotency) is tetraploid embryo complementation (TEC)3-5. Technically, TEC involves electrofusion of two-cell embryos to generate tetraploid (4n) one-cell embryos that can be cultured in vitro to the blastocyst stage6. Diploid (2n) pluripotent stem cells (e.g. ESCs or iPSCs) are then injected into the blastocoel cavity of the tetraploid blastocyst and transferred to a recipient female for gestation (see Figure 1). The tetraploid component of the complemented embryo contributes almost exclusively to the extraembryonic tissues (placenta, yolk sac), whereas the diploid cells constitute the embryo proper, resulting in a fetus derived entirely from the injected stem cell line.
Recently, we reported the derivation of iPSC lines that reproducibly generate adult mice via TEC1. These iPSC lines give rise to viable pups with efficiencies of 5-13%, which is comparable to ESCs3,4,7 and higher than that reported for most other iPSC lines8-12. These reports show that direct reprogramming can produce fully pluripotent iPSCs that match ESCs in their developmental potential and efficiency of generating pups in TEC tests. At present, it is not clear what distinguishes between fully pluripotent iPSCs and less potent lines13-15. Nor is it clear which reprogramming methods will produce these lines with the highest efficiency. Here we describe one method that produces fully pluripotent iPSCs and "all- iPSC" mice, which may be helpful for investigators wishing to compare the pluripotency of iPSC lines or establish the equivalence of different reprogramming methods.

Generating induced pluripotent stem cell (iPSC) lines produces lines of differing developmental potential even when they pass standard tests for pluripotency. Here we describe a protocol to produce mice derived entirely from iPSCs, which defines the iPSC lines as possessing full pluripotency1.

The production of induced pluripotent stem cells (iPSCs) from somatic cells provides a means to create valuable tools for basic research and may also ...

Protein Transfection of Mouse Lung

Increasing protein expression enables researchers to better understand the functional role of that protein in regulating key biological processes1. In the lung, this has been achieved typically through genetic approaches that utilize transgenic mice2,3 or viral or non-viral vectors that elevate protein levels via increased gene expression4. Transgenic mice are costly and time-consuming to generate and the random insertion of a transgene or chronic gene expression can alter normal lung development and thus limit the utility of the model5. While conditional transgenics avert problems associated with chronic gene expression6, the reverse tetracycline-controlled transactivator (rtTA) mice, which are used to generate conditional expression, develop spontaneous air space enlargement7. As with transgenics, the use of viral and non-viral vectors is expensive8 and can provoke dose-dependent inflammatory responses that confound results9 and hinder expression10. Moreover, the efficacy of repeated doses are limited by enhanced immune responses to the vector11,12. Researchers are developing adeno-associated viral (AAV) vectors that provoke less inflammation and have longer expression within the lung13.
Using &beta;-galactosidase, we present a method for rapidly and effectively increasing protein expression within the lung using a direct protein transfection technique. This protocol mixes a fixed amount of purified protein with 20 &mu;l of a lipid-based transfection reagent (Pro-Ject, Pierce Bio) to allow penetration into the lung tissue itself. The liposomal protein mixture is then injected into the lungs of the mice via the trachea using a microsprayer (Penn Century, Philadelphia, PA). The microsprayer generates a fine plume of liquid aerosol throughout the lungs. Using the technique we have demonstrated uniform deposition of the injected protein throughout the airways and the alveoli of mice14. The lipid transfection technique allows the use of a small amount of protein to achieve effect. This limits the inflammatory response that otherwise would be provoked by high protein administration. Indeed, using this technique we published that we were able to significantly increase PP2A activity in the lung without affecting lung lavage cellularity15. Lung lavage cellularity taken 24 hr after challenge was comparable to controls (27&plusmn;4 control vs. 31&plusmn;5 albumin transfected; N=6 per group). Moreover, it increases protein levels without inducing lung developmental changes or architectural changes that can occur in transgenic models. However, the need for repeated administrations may make this technique less favorable for studies examining the effects of long-term increases in protein expression. This would be particularly true for proteins with short half-lives.

Transgenic mice or viral vectors have been used to increase protein expression within the lung. However, these techniques are time-consuming, technically challenging and have off-target effects that can confound results. Our protein transfection protocol uses a lipid based transfection reagent and an ultrafine microsprayer to uniformly deliver active protein to lung cells.

Increasing protein expression enables researchers to  better understand the functional role of that protein in regulating key  biological processes1. In ...

Examination of Drosophila Larval Tracheal Terminal Cells by Light Microscopy

Cell shape is critical for cell function. However, despite the importance of cell morphology, little is known about how individual cells generate specific shapes. Drosophila tracheal terminal cells have become a powerful genetic model to identify and elucidate the roles of genes required for generating cellular morphologies. Terminal cells are a component of a branched tubular network, the tracheal system that functions to supply oxygen to internal tissues. Terminal cells are an excellent model for investigating questions of cell shape as they possess two distinct cellular architectures. First, terminal cells have an elaborate branched morphology, similar to complex neurons; second, terminal cell branches are formed as thin tubes and contain a membrane-bound intracellular lumen. Quantitative analysis of terminal cell branch number, branch organization and individual branch shape, can be used to provide information about the role of specific genetic mechanisms in the making of a branched cell. Analysis of tube formation in these cells can reveal conserved mechanisms of tubulogenesis common to other tubular networks, such as the vertebrate vasculature. Here we describe techniques that can be used to rapidly fix, image, and analyze both branching patterns and tube formation in terminal cells within Drosophila larvae. These techniques can be used to analyze terminal cells in wild-type and mutant animals, or genetic mosaics. Because of the high efficiency of this protocol, it is also well suited for genetic, RNAi-based, or drug screens in the Drosophila tracheal system.

Examination of Drosophila Larval Tracheal Terminal Cells by Light Microscopy

Here, we present a method for light microscopy analysis of tracheal terminal cells in Drosophila larvae. This method allows for quick examination of branch and lumen morphology in whole animals and would be useful for analysis of individual mutants or screens for mutations affecting terminal cell development.

Cell shape is critical for cell function. However, despite the importance of cell morphology, little is known about how individual cells generate specific ...