The experimental protocols were approved by the Institutional Animal Care and Use Committee at The Children&#39;s Hospital of Philadelphia.
1. Creation of Injection Pipettes
<ol>
	<li>Using a vertical micropipette puller, pull a 100 &#181;L microcapillary pipette (Figure&#160;1A - 1C). Calibrate the micropipette puller so that the tapered end is &#62; 1 cm long. 
	NOTE: Initially, the settings of the puller should be adjusted for an optimum length. A higher heat setting will make the tip longer, and a higher pull setting will make the diameter of the tip narrower.</li>
	<li>Cut the tapered end so that it is &#8805; 1 cm long. Ensure that the internal diameter at the tip of the needle is between 70 &#181;m and 100 &#181;m and that it is inversely proportional to the length of the tapered end. 
	NOTE: The internal diameter also depends on the calibration of the micropipette puller. See the instructions from the manufacturer of the vertical micropipette puller or any preferred micropipette puller type.</li>
	<li>After ensuring that the needle has the correct internal diameter, create the bevel of 15 - 20 degrees by sharpening the tip using a micropipette beveller with a diamond sharpening wheel (Figure&#160;2A - 2C). Make sure to rest the tip gently on the wheel without too much pressure, to decrease chances of breaking or cracking the tip. 
	NOTE: A paintbrush can be used to wipe away any debris that builds up on the needle tip.</li>
	<li>Evaluate the tip under a microscope and ensure that the tip is round without any chips or cracks. Reevaluate the internal diameter to make sure it is between 70 &#181;m and 100 &#181;m (Figure&#160;2D - 2H).</li>
	<li>Draw lines on the rest of the needle to designate 5 &#181;L of volume between them (e.g., needles with an internal diameter of 1.3 mm should have lines drawn at 3.77 mm increments).</li>
	<li>Autoclave the needles prior to use in surgery and handle them with sterile gloves.&#160;</li>
</ol>
2. In utero Injections
<ol>
	<li>Prepare the necessary instruments by autoclaving them ahead of time. Include essential instruments such as microinjector needle holder, a surgical needle driver, a pair of Adson forceps, a pair of curved regular tissue scissors, a 1 mL insulin syringe, a couple of cotton-tip applicators, a transfer pipette, a 50 mL conical tube, and a pack of 4-0 polyglactin 910 sutures.</li>
	<li>Using a sterile technique, attach the needle to the needle holder and plug it into the microinjector. 
	NOTE: The settings of the compressed nitrogen used are as followed: inject 4 - 6 psi, balance 0 psi. Depending on what is being injected, specifically, the viscosity of the injectate, as well as the size of the micropipette, the injection times vary between 0.3 - 1.5 s.</li>
	<li>Clean out the needle tip of any possible debris by drawing up 5 - 10 &#181;L of sterile 1x phosphate-buffered saline (PBS) and then clearing it out. Repeat this 2 - 3x.</li>
	<li>Prepare pregnant 2- to 6-month-old female mice for surgery by shaving their abdomens with a clipper. Be careful not to damage the nipples. Administer oral pain medication (e.g., 100 &#181;L of 1.5 mg/mL meloxicam oral suspension per mouse).</li>
	<li>Start filling the needle with the desired material (cells/vector/drug) at the desired volume. Be careful not to break the needle tip while filling the needle. 
	NOTE: The volume of injection per fetus varies depending on the specific experimental design. 20 &#181;L works well for injecting a large number of cells (i.e., up to 107 cells into the vitelline vein. For instance, we delivered 1 x 107 whole bone marrow cells isolated from C57BL/6TgN(act-EGFP)OsbY01 [&#34;B6 Green Fluorescent Protein (GFP)&#34;] mice via the vitelline vein into gestational day-14 Balb/c fetuses. For viral vector injections, a single injection of 10 &#181;L of a 1:1 diluted vector with PBS works well.</li>
	<li>To calibrate the injection time, take the following steps.
	<ol>
		<li>Push the Mode button 3x on the microinjector to get to the injection calibration screen. Adjust the injection time by adding intervals of 10 or 100 ms and push the Mode button 2x.</li>
		<li>Push the Balance button and push the foot pedal once. Now push the pedal again and assess how much volume is emptied out of the needle per push. If not calibrated to the desired volume of 5 - 20 &#181;L per pedal push, repeat steps 2.6.1 and 2.6.2. 
		NOTE: Generally, it is good to calibrate each push to deliver half the total target volume at a time. While it is possible to inject more than 30 &#181;L or even 40 &#181;L of the total volume, we do not generally go over 20 &#181;L per fetus, intravenous or intra-amniotic.</li>
	</ol>
	</li>
	<li>Fill the needle up to the desired level.</li>
	<li>Start delivering anesthesia to the mouse by adjusting the oxygen flowmeter to 1 L/min and the isoflurane vaporizer to 3%.</li>
	<li>Confirm whether the mouse is anesthetized by checking for the absence of the pedal reflex. Transfer the mouse to a heating pad in a supine position.</li>
	<li>Apply lubricant eye gel to avoid corneal desiccation. Secure the mouse in place by taping the upper and lower limbs to the pad.</li>
	<li>Prep the abdomen with chlorhexidine scrub followed by alcohol&#160;and inject a local anesthetic (e.g., 100 &#181;L of 0.25% bupivacaine) subcutaneously (Figure 3A).</li>
	<li>With scissors, make a 1 - 2 cm skin incision so that the lower border is no closer than 1 cm to the introitus; the fascia beneath is very thin and translucent.</li>
	<li>Identify the midline of the fascia which is more transparent than the surrounding area. Be careful not to injure the epigastric vessels which lie on either side of the midline. Should the epigastric vessels get injured, hold pressure with cotton-tip applicators to stop the bleeding.</li>
	<li>Using Adson forceps, pinch the fascia without grabbing any of the underlying organs such as the intestines, bladder, or fetuses. Open the fascia with scissors, being careful not to damage any of the organs. Once safely in the abdomen, extend the fascial incision. Make it no longer than the skin incision.</li>
	<li>Use cotton-tip applicators to move the intestines into the upper part of the abdomen, thus exposing the gravid uterus. Deliver the uterus out of the incision, carefully identifying the right and left ovaries to ensure all fetuses are counted (Figure 3B).</li>
	<li>Place the left uterus back into the abdomen so that only the right uterus is exposed; this prevents the desiccation of the uterus and keeps the non-injected fetuses warm.</li>
	<li>Hold the most lateral fetus/amniotic sac between the thumb and index fingers of the operator&#39;s non-dominant hand (Figure 3C). Always be gentle as to not cause any damage to the fetuses.</li>
	<li>Position the dissection microscope (a 10X magnification is ideal) and adjust the focus so that the fetus is in view. Adjust the lighting for a better visualization.</li>
	<li>Identify the part that will be injected (vitelline vein, amnion).For intravenous injections, visualize both the vitelline veins and their anastomosis first. For intra-amniotic injections, orient the fetus with the right side in view.</li>
	<li>Reach the target space with the needle as described below.
	<ol>
		<li>For an intravenous injection, do as follows.
		<ol>
			<li>Rotate the uterus so that the vitelline vein that is being injected is parallel to the tip of the needle; keep in mind that the injections must be made towards the anastomosis of the two veins.</li>
			<li>Lay the needle on the uterus at a 5&#176; angle and pierce the uterine wall. Now that the tip is between the uterine wall and the amniotic sac, place the tip directly atop the vitelline vein.</li>
			<li>At a nearly tangential angle, glide the needle over the vein until the bevel pierces and advances into the vessel; this is evident by a flash of blood seen in the needle tip (Figure 3D). 
			NOTE: Accessing the vein may take a few tries as the needle may not pierce the vein with the first glide over the vein.</li>
		</ol>
		</li>
		<li>For an intra-amniotic injection, do as follows.
		<ol>
			<li>Rotate the amniotic sac and find a location devoid of vessels to pierce.</li>
			<li>Point the needle perpendicular to the uterine wall and pierce through the uterus, the yolk sac, and then the amniotic sac. Be careful not to pierce through any fetal tissue. Make sure the needle has passed between the limbs as this confirms that the needle is in the amniotic sac. Then proceed with the injection.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Inject the appropriate volume of material desired (usually 10 - 20 &#181;L) by pushing the foot pedal. 
	NOTE: Because the injector must maintain the visualization of the needle tip through the microscope at all times, a second person must read the markings on the needle to quantify the injected amount and inform the injector how much volume is left to inject. A discussion prior to the injection between the injector and assistant is important to avoid any confusion and delay. This is especially important for intravenous injections because a delayed removal of the needle will allow a backflow of venous blood into the needle and result in an inaccurate dosing.</li>
	<li>Withdraw the needle from the injection site once the desired volume is delivered. As there may be some bleeding from the vessel puncture site with intravenous injections, hold pressure with the side of the needle for 10 - 15 s to stop the bleeding.</li>
	<li>Proceed to the next fetus. Continue until all the fetuses of the right uterine horn have been injected.</li>
	<li>Remove the left uterine horn from the abdomen and replace the right uterine horn back inside the peritoneal cavity. 
	NOTE: Occasionally, the needle needs to be refilled with the injectant.</li>
	<li>Once all fetuses have been injected, replace the uterus into the abdomen (Figure 3E). Make sure to avoid a uterine or intestinal volvulus.</li>
	<li>With a disposable transfer pipette, place roughly 2 mL of 1x PBS into the abdomen to replace any insensible losses.</li>
	<li>Close the fascia and abdomen in one continuous layer using 4-0 polyglactin 910 sutures to avoid injuring the underlying organs during the closure (Figure&#160;3F - 3G).</li>
	<li>Remove the tape and transfer the mouse to a cage underneath a heat lamp. Be careful not to place the heat lamp too close to the mouse. Make sure the cage has bedding, food, and water. 
	NOTE: A thermostatically controlled warm chamber may also be used. The mouse is awake when it is upright and walking.</li>
	<li>Observe the mouse daily and give pain medication as needed. 
	NOTE: We routinely give meloxicam on postoperative days 1 and 2, and sometimes on day 3 if the mouse shows signs of pain.</li>
	<li>If doing a batch surgery with the same injection material, clean out the injection needle with sterile PBS. If injecting with a different material, dispose of the needle in a sharps container and use a new needle. 
	NOTE: We recommend fostering the pups with surrogate dams immediately after birth in case the dam mounts an immune response to the injectant and transfers antibodies to the pups via breast milk.</li>
</ol>

<ol>
	<li>Loukogeorgakis, S., Flake, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+utero+stem+cell+and+gene+therapy:+current+status+and+future+perspectives.">In utero stem cell and gene therapy: current status and future perspectives.</a> European Journal of Pediatric Surgery. 24, 237-245 (2014).</li><li>Vrecenak, J., Flake, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+utero+hematopoietic+cell+transplantation:+recent+progress+and+the+potential+for+clinical+application.">In utero hematopoietic cell transplantation: recent progress and the potential for clinical application.</a> Cytotherapy. 15, 525-535 (2013).</li><li>Peranteau, W., 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=Correction+of+murine+hemoglobinopathies+by+prenatal+tolerance+induction+and+postnatal+nonmyeloablative+allogeneic+BM+transplants.">Correction of murine hemoglobinopathies by prenatal tolerance induction and postnatal nonmyeloablative allogeneic BM transplants.</a> Blood. 126 (10), 1245-1254 (2015).</li><li>Vrecenak, J., 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=Stable+Long-Term+Mixed+Chimerism+Achieved+in+a+Canine+Model+of+Allogeneic+in+utero+Hematopoietic+Cell+Transplantation.">Stable Long-Term Mixed Chimerism Achieved in a Canine Model of Allogeneic in utero Hematopoietic Cell Transplantation.</a> Blood. 124 (12), 1987-1995 (2014).</li><li>Peranteau, W., 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=CD26+Inhibition+Enhances+Allogeneic+Donor-Cell+Homing+and+Engraftment+after+in+utero+Hematopoietic-Cell+Transplantation.">CD26 Inhibition Enhances Allogeneic Donor-Cell Homing and Engraftment after in utero Hematopoietic-Cell Transplantation.</a> Blood. 108 (13), 4268-4274 (2006).</li><li>Waddington, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+utero+gene+transfer+of+human+factor+IX+to+fetal+mice+can+induce+postnatal+tolerance+of+the+exogenous+clotting+factor.">In utero gene transfer of human factor IX to fetal mice can induce postnatal tolerance of the exogenous clotting factor.</a> Blood. 101 (4), 1359-1366 (2003).</li><li>Stitelman, D., 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=Developmental+Stage+Determines+Efficiency+of+Gene+Transfer+to+Muscle+Satellite+Cells+by+in+utero+Delivery+of+Adeno-Associated+Virus+Vector+Serotype+2/9.">Developmental Stage Determines Efficiency of Gene Transfer to Muscle Satellite Cells by in utero Delivery of Adeno-Associated Virus Vector Serotype 2/9.</a> Molecular Therapy - Methods &amp; Clinical Development. 1, 14040 (2014).</li><li>Endo, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+Transfer+to+Ocular+Stem+Cells+by+Early+Gestational+Intraamniotic+Injection+of+Lentiviral+Vector.">Gene Transfer to Ocular Stem Cells by Early Gestational Intraamniotic Injection of Lentiviral Vector.</a> Molecular Therapy. 15 (3), 579-587 (2007).</li><li>Boelig, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Intravenous+Route+of+Injection+Optimizes+Engraftment+and+Survival+in+the+Murine+Model+of+In+utero+Hematopoietic+Cell+Transplantation.">The Intravenous Route of Injection Optimizes Engraftment and Survival in the Murine Model of In utero Hematopoietic Cell Transplantation.</a> Biology of Blood and Marrow Transplantation. 22 (6), 991-999 (2016).</li><li>Wu, C., 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=Intra-amniotic+Transient+Transduction+of+the+Periderm+with+a+Viral+Vector+Encoding+TGF&#946;3+Prevents+Cleft+Palate+in+Tgf&#946;3-/-.+Mouse+Embryos.">Intra-amniotic Transient Transduction of the Periderm with a Viral Vector Encoding TGF&#946;3 Prevents Cleft Palate in Tgf&#946;3-/-. Mouse Embryos.</a> Molecular Therapy. 1, 8-17 (2013).</li><li>Roybal, J., Endo, M., Radu, A., Zoltick, P., Flake, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+gestational+gene+transfer+of+IL-10+by+systemic+administration+of+lentiviral+vector+can+prevent+arthritis+in+a+murine+model.">Early gestational gene transfer of IL-10 by systemic administration of lentiviral vector can prevent arthritis in a murine model.</a> Gene Therapy. 18 (7), 719-726 (2011).</li><li>Reay, D., 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=Full-Length+Dystrophin+Gene+Transfer+to+the+Mdx+Mouse+in+utero.">Full-Length Dystrophin Gene Transfer to the Mdx Mouse in utero.</a> Gene Therapy. 15 (7), 531-536 (2008).</li><li>Ahmed, S., Waddington, S., Boza-Mor&#225;n, M., Y&#225;&#241;ez-Mu&#241;oz, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-Efficiency+Transduction+of+Spinal+Cord+Motor+Neurons+by+Intrauterine+Delivery+of+Integration-Deficient+Lentiviral+Vectors.">High-Efficiency Transduction of Spinal Cord Motor Neurons by Intrauterine Delivery of Integration-Deficient Lentiviral Vectors.</a> Journal of Controlled Release. 273, 99-107 (2018).</li><li>Haddad, M., Donsante, A., Zerfas, P., Kaler, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fetal+Brain-Directed+AAV+Gene+Therapy+Results+in+Rapid,+Robust,+and+Persistent+Transduction+of+Mouse+Choroid+Plexus+Epithelia.">Fetal Brain-Directed AAV Gene Therapy Results in Rapid, Robust, and Persistent Transduction of Mouse Choroid Plexus Epithelia.</a> Molecular Therapy - Nucleic Acids. 2, 101 (2013).</li><li>Nijagal, A., Le, T., Wegorzewska, M., MacKenzie, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+mouse+model+of+in+utero+transplantation.">A mouse model of in utero transplantation.</a> Journal of Visualized Experiments. (47), e2303 (2011).</li><li>Davey, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Jaagsiekte+Sheep+Retrovirus+Pseudotyped+Lentiviral+Vector-Mediated+Gene+Transfer+to+Fetal+Ovine+Lung.">Jaagsiekte Sheep Retrovirus Pseudotyped Lentiviral Vector-Mediated Gene Transfer to Fetal Ovine Lung.</a> Gene Therapy. 19 (2), 201-209 (2011).</li></ol>

The authors have nothing to disclose.

In utero transplantation is a potential therapy for many congenital disorders that can be diagnosed early in gestation. The murine model for IUT allows researchers to explore the fetal environment or to experiment with different therapies. Depending on what is being injected and what is being targeted, intravenous or intra-amniotic in utero transplantation can provide a reliable delivery of an injectant into the desired space.
When targeting specific organs, it is important t...

Recent advances in antenatal screening and diagnosis have brought to light the possibility of treating the fetus for a number of congenital disorders which do not have adequate postnatal treatment options and result in significant morbidity and mortality. Specifically, in utero hematopoietic stem cell transplantation (IUHCT) and gene therapy/genome editing have the potential to take advantage of normal developmental properties of the fetus to treat congenital hematologic, immune, and genetic disorders more efficiently than postnatal HSC transplantation and gene therapy/genome editing can do1,2. Specifically, due to the small size of the fetus, the donor cell or viral vector dose can be maximized per the weight of the recipient. Additionally, the immunologic immaturity of the fetus allows donor HSCs to be injected without the myeloablative and immunosuppressive conditioning that is required in postnatal transplant protocols. Similarly, viral vectors carrying a therapeutic transgene or genome editing technology can be injected without a limiting immune response to either the transgene product or the viral vector. Finally, the accessibility and proliferative nature of fetal stem/progenitor cells afford the possibility of a more efficient transduction of target progenitor cells, as well as certain modes of genome editing (homology-directed repair) which require cycling cells to occur efficiently. The murine model serves as an insightful and affordable means to address important questions in stem cell biology and immunology prior to experimenting in pre-clinical large animal models and, as such, has served as the primary model in which IUHCT and in utero gene therapy have been explored1,2,3.
Although many variables play an important role in the success of IUHCT and in utero gene therapy/genome editing in murine and large animal models, a key variable is the method of delivery of the HSCs or viral vector. The delivery of large doses of donor HSCs with a first-pass effect occurring in the fetal liver, the hematopoietic organ at the time of the IUHCT, has been shown to be instrumental in achieving macrochimeric levels of engraftment in mouse and large animal models4,5. This was achieved via an injection of donor cells via the vitelline vein in the mouse model and via an intra-cardiac injection in the canine model. The route of injection also plays a fundamental role in targeting progenitor cells of different organs during development. For example, an intravenous injection via the vitelline vein has been shown to efficiently transduce cardiomyocytes and hepatocytes following a late gestation injection6,7. Alternatively, an intra-amniotic injection of viral vectors allows the targeting of organs that are physically exposed based on the embryonic folding/development at the time of the injection8. This is best exemplified by the targeting of respiratory epithelium via an intra-amniotic injection late in the gestation to take advantage of normal fetal &#34;breathing&#34; movements, which exposes the respiratory tract to the viral vector in the amniotic fluid9. These two modes of IUT, intravenous via the vitelline vein and intra-amniotic, have been the basis for multiple past and ongoing experiments in our laboratory. In this protocol, we describe in detail the methods for performing intravenous and intra-amniotic IUT in the murine model.

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	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Gloves</td>
			<td style="width:168px;">Cardinal Health</td>
			<td style="width:147px;">2D73DP65</td>
			<td style="width:231px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Adson Forceps w/ teeth</td>
			<td style="width:168px;">Fine Science Tools</td>
			<td style="width:147px;">11027-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Adson Forceps w/o teeth</td>
			<td style="width:168px;">Fine Science Tools</td>
			<td style="width:147px;">11006-12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Curved scissors</td>
			<td style="width:168px;">Fine Science Tools</td>
			<td style="width:147px;">14075-11</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Heavy Scissors</td>
			<td style="width:168px;">Fine Science Tools</td>
			<td style="width:147px;">14002-13</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Needle Driver</td>
			<td style="width:168px;">Fine Science Tools</td>
			<td style="width:147px;">12005-15</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Vicryl 2.0</td>
			<td style="width:168px;">Ethicon</td>
			<td style="width:147px;">JB945</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Transfer Pipette</td>
			<td style="width:168px;">Medline</td>
			<td style="width:147px;">GSI135010</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Cotton Tipped Applicators</td>
			<td style="width:168px;">Medline</td>
			<td style="width:147px;">MDS202000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">50 mL Conical tube</td>
			<td style="width:168px;">Fischer Scientific</td>
			<td style="width:147px;">14-432-22</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Tape</td>
			<td style="width:168px;">3M</td>
			<td style="width:147px;">1527-1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Eye lubricant</td>
			<td style="width:168px;">Major LubriFresh</td>
			<td style="width:147px;">0904-6488</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Heating Pad</td>
			<td style="width:168px;">K&#38;H</td>
			<td style="width:147px;">3060</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Stereomicroscope</td>
			<td style="width:168px;">Leica</td>
			<td style="width:147px;">MZ16</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Injector</td>
			<td style="width:168px;">Narishige</td>
			<td style="width:147px;">HI01PK01</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Glass Capillary tubes</td>
			<td style="width:168px;">Kimble</td>
			<td style="width:147px;">71900-100</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Vertical Micropipette Puller</td>
			<td style="width:168px;">Sutter Instruments</td>
			<td style="width:147px;">P-30</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Microelectrode Beveler</td>
			<td style="width:168px;">Sutter Instruments</td>
			<td style="width:147px;">BV-10</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">IM-300 Pneumatic Microinjector</td>
			<td style="width:168px;">Narishige</td>
			<td style="width:147px;">IM-300</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Insulin Syringe&#160;</td>
			<td style="width:168px;">BD&#160;</td>
			<td style="width:147px;">305935</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Filter</td>
			<td style="width:168px;">Genesee Scientific</td>
			<td style="width:147px;">25-244</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Compac5 Anesthesia Machine</td>
			<td style="width:168px;">VetEquip Compac5</td>
			<td style="width:147px;">901812&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Isoflurane</td>
			<td style="width:168px;">Piramal Critical Care</td>
			<td style="width:147px;">NDC 66794-017-25</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">N2 gas</td>
			<td style="width:168px;">Airgas</td>
			<td style="width:147px;">NI 125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">O2 gas</td>
			<td style="width:168px;">Airgas</td>
			<td style="width:147px;">OX 125</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:281px;">Ad-GFP viral vector</td>
			<td style="width:168px;">Penn Vector Core</td>
			<td style="width:147px;">H5&#39;.040.CMV.eGFP</td>
			<td></td>
		</tr>
	</tbody>
</table>

intravenous and intra-amniotic in utero transplantation in the murine model

In utero transplantation (IUT) is a unique and versatile mode of therapy that can be used to introduce stem cells, viral vectors, or any other substances early in the gestation. The rationale behind IUT for therapeutic purposes is based on the small size of the fetus, the fetal immunologic immaturity, the accessibility and proliferative nature of the fetal stem or progenitor cells, and the potential to treat a disease or the onset of symptoms prior to birth. Taking advantage of these normal developmental properties of the fetus, the delivery of hematopoietic stem cells (HSC) via an IUT has the potential to treat congenital hematologic disorders such as sickle cell disease, without the required myeloablative or immunosuppressive conditioning required for postnatal HSC transplants. Similarly, the accessibility of progenitor cells in multiple organs during development potentially allows for a more efficient targeting of stem/progenitor cells following an IUT of viral vectors for gene therapy or genome editing. Additionally, IUT can be used to study normal developmental processes including, but not limited to, the development of immunologic tolerance. The murine model provides a valuable and affordable means to understanding the potential and limitations of IUT prior to pre-clinical large animal studies and an eventual clinical application. Here, we describe a protocol for performing an IUT in the murine fetus through intravenous and intra-amniotic routes. This protocol has been used successfully to elucidate the necessary conditions and mechanisms behind in utero hematopoietic stem cell transplantation, tolerance induction, and in utero gene therapy.

Survival and engraftment are important measures of success for IUHCT experiments. Depending on the specific endpoints of an experiment, fetuses that received an IUHCT may be analyzed prenatally by a C-section or postnatally. On average, the survival rates after intravenous injections range from 75 - 100%. The survival rates after intra-amniotic injections tend to fair better than intravenous injections, at around 85 - 100%.
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Watch this Scientific Journal Video about Intravenous and Intra-amniotic In Utero Transplantation in the Murine Model at JoVE.com

Intravenous and Intra-amniotic In Utero Transplantation in the Murine Model

We describe a protocol for performing an in utero transplantation (IUT) through intravenous and intra-amniotic routes of injection in the murine model. This protocol can be used to introduce cells, viral vectors, and other substances into the unique immune-tolerant fetal environment.

Intravenous and Intra-amniotic In Utero Transplantation in the Murine Model

In utero transplantation (IUT) is a unique and versatile mode of therapy that can be used to introduce stem cells, viral vectors, or any other substances ...

intravenous-intra-amniotic-utero-transplantation-murine

Universidad San Sebastian

Research

JoVE Journal

Developmental Biology

9.4K Views.  Children's Hospital of Philadelphia. We describe a protocol for performing an in utero transplantation (IUT) through intravenous and intra-amniotic routes of injection in the murine model. This protocol can be used to introduce cells, viral vectors, and other substances into the unique immune-tolerant fetal environment.

Video: Intravenous and Intra-amniotic In Utero Transplantation in the Murine Model

Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye

The zebrafish model is an emerging system for the study of neuromuscular disorders. In the study of neuromuscular diseases, the integrity of the muscle membrane is a critical disease determinant. To date, numerous neuromuscular conditions display degenerating muscle fibers with abnormal membrane integrity; this is most commonly observed in muscular dystrophies. Evans Blue Dye (EBD) is a vital, cell permeable dye that is rapidly taken into degenerating, damaged, or apoptotic cells; in contrast, it is not taken up by cells with an intact membrane. EBD injection is commonly employed to ascertain muscle integrity in mouse models of neuromuscular diseases. However, such EBD experiments require muscle dissection and/or sectioning prior to analysis. In contrast, EBD uptake in zebrafish is visualized in live, intact preparations. Here, we demonstrate a simple and straightforward methodology for performing EBD injections and analysis in live zebrafish. In addition, we demonstrate a co-injection strategy to increase efficacy of EBD analysis. Overall, this video article provides an outline to perform EBD injection and characterization in zebrafish models of neuromuscular disease.

In this study, we describe a straightforward method to perform Evans Blue Dye (EBD) analysis on zebrafish larvae. This technique is a powerful tool for the characterization of skeletal muscle integrity and delineation of zebrafish models of muscular dystrophy, and is a valuable method for the development of novel therapeutics.

The zebrafish model is an emerging system for the study of neuromuscular disorders.  In the study of neuromuscular diseases, the integrity of the muscle ...

Spatial and Temporal Analysis of Active ERK in the C. elegans Germline

The evolutionarily conserved&#160;extracellular signal transducing RTK-RAS-ERK pathway is an important kinase-signaling cascade that controls multiple cellular and developmental processes principally via activation of ERK, the terminal kinase of the pathway. Tight regulation of ERK activity is essential for normal development and homeostasis; overly active ERK results in excessive cellular proliferation, while underactive ERK causes cell death. C. elegans is a powerful model system that has helped characterize the function and regulation of RTK-RAS-ERK signaling pathway during development. In particular, the RTK-RAS-ERK pathway is essential for C. elegans germline development, which is the focus of this method. Using antibodies specific to the active, diphosphorylated form of ERK (dpERK), the stereotypical localization pattern can be visualized within the germline. Because this pattern is both spatially and temporally controlled, the ability to reproducibly assay dpERK is useful to identify regulators of the pathway that affect dpERK signal duration and amplitude and thus germline development. Here we demonstrate how to successfully dissect, stain, and image dpERK within the C. elegans gonad. This method can be adapted for spatial localization of any signaling or structural protein in the C. elegans gonad, provided an antibody compatible with immunofluorescence is available.

Spatial and Temporal Analysis of Active ERK in the C. elegans Germline

We present an immunofluorescence&#160;imaging-based method for spatial and temporal localization of active ERK in the dissected C. elegans gonad. The protocol described here can be adapted for visualization of any signaling or structural protein in the C. elegans gonad, provided a suitable antibody reagent is available.

The evolutionarily conserved&#160;extracellular signal transducing RTK-RAS-ERK pathway is an important kinase-signaling cascade that controls multiple ...

Culture of Murine Embryonic Metatarsals: A Physiological Model of Endochondral Ossification

The fundamental process of endochondral ossification is under tight regulation in the healthy individual so as to prevent disturbed development and/or longitudinal bone growth. As such, it is imperative that we further our understanding of the underpinning molecular mechanisms involved in such disorders so as to provide advances towards human and animal patient benefit. The mouse metatarsal organ explant culture is a highly physiological ex vivo model for studying endochondral ossification and bone growth as the growth rate of the bones in culture mimic that observed in vivo. Uniquely, the metatarsal organ culture allows the examination of chondrocytes in different phases of chondrogenesis and maintains cell-cell and cell-matrix interactions, therefore providing conditions closer to the in vivo situation than cells in monolayer or 3D culture. This protocol describes in detail the intricate dissection of embryonic metatarsals from the hind limb of E15 murine embryos and the subsequent analyses that can be performed in order to examine endochondral ossification and longitudinal bone growth.

We present a protocol to dissect and culture embryonic day 15 (E15) murine metatarsal bones. This highly physiological ex vivo model of endochondral ossification provides conditions closer to the in vivo situation than cells in monolayer or 3D culture and is a vital tool for investigating bone growth and development.

The fundamental process of endochondral ossification is under tight regulation in the healthy individual so as to prevent disturbed development and/or ...

A Novel Mammary Fat Pad Transplantation Technique to Visualize the Vessel Generation of Vascular Endothelial Stem Cells

Endothelial cells (ECs) are the fundamental building blocks of the vascular architecture and mediate vascular growth and remodeling to ensure proper vessel development and homeostasis. However, studies on endothelial lineage hierarchy remain elusive due to the lack of tools to gain access as well as to directly evaluate their behavior in vivo. To address this shortcoming, a new tissue model to study angiogenesis using the mammary fat pad has been developed. The mammary gland develops mostly in the postnatal stages, including puberty and pregnancy, during which robust epithelium proliferation is accompanied by extensive vascular remodeling. Mammary fat pads provide space, matrix, and rich angiogenic stimuli from the growing mammary epithelium. Furthermore, mammary fat pads are located outside the peritoneal cavity, making them an easily accessible grafting site for assessing the angiogenic potential of exogenous cells. This work also describes an efficient tracing approach using fluorescent reporter mice to specifically label the targeted population of vascular endothelial stem cells (VESCs) in vivo. This lineage tracing method, coupled with subsequent tissue whole-mount microscopy, enable the direct visualization of targeted cells and their descendants, through which the proliferation capability can be quantified and the differentiation commitment can be fate-mapped. Using these methods, a population of bipotent protein C receptor (Procr) expressing VESCs has recently been identified in multiple vascular systems. Procr+ VESCs, giving rise to both new ECs and pericytes, actively contribute to angiogenesis during development, homeostasis, and injury repair. Overall, this manuscript describes a new mammary fat pad transplantation and in vivo lineage tracing techniques that can be used to evaluate the stem cell properties of VESCs.

This work demonstrates a novel approach to assess the proliferation, differentiation, and vessel-forming potential of vascular endothelial stem cells (VESCs) through mammary fat pad transplantation followed by whole-mount tissue preparation for microscopic observation. A lineage tracing strategy to investigate the behavior of VESCs in vivo is also presented.

Endothelial cells (ECs) are the fundamental building blocks of the vascular architecture and mediate vascular growth and remodeling to ensure proper ...

Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains

Nervous system development involves a sequential series of events that are coordinated by several signaling pathways and regulatory networks. Many of the proteins involved in these pathways are evolutionarily conserved between mammals and other eukaryotes, such as the fruit fly Drosophila melanogaster, suggesting that similar organizing principles exist during the development of these organisms. Importantly, Drosophila has been used extensively to identify cellular and molecular mechanisms regulating processes that are required in mammals including neurogenesis, differentiation, axonal guidance, and synaptogenesis. Flies have also been used successfully to model a variety of human neurodevelopmental diseases. Here we describe a protocol for the step-by-step microdissection, fixation, and immunofluorescent localization of proteins within the adult Drosophila brain. This protocol focuses on two example neuronal populations, mushroom body neurons and retinal photoreceptors, and includes optional steps to trace individual mushroom body neurons using Mosaic Analysis with a Repressible Cell Marker (MARCM) technique. Example data from both wild-type and mutant brains are shown along with a brief description of a scoring criteria for axonal guidance defects. While this protocol highlights two well-established antibodies for investigating the morphology of mushroom body and photoreceptor neurons, other Drosophila brain regions and the localization of proteins within other brain regions can also be investigated using this protocol.

Dissection and Immunofluorescent Staining of Mushroom Body and Photoreceptor Neurons in Adult Drosophila melanogaster Brains

This protocol describes the dissection and immunostaining of adult Drosophila melanogaster brain tissues. Specifically, this protocol highlights the use of Drosophila mushroom body and photoreceptor neurons as example neuronal subsets that can be accurately used to uncover general principles underlying many aspects of neuronal development.

Nervous system development involves a sequential series of events that are coordinated by several signaling pathways and regulatory networks. Many of the ...

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain and protect cellular identities. The conversion of germ cells into specific neurons in the nematode Caenorhabditis elegans (C. elegans) is a powerful tool for performing genetic screens in order to dissect regulatory pathways that safeguard established cell identities. Reprogramming of germ cells to a specific type of neurons termed ASE requires transgenic animals that allow broad over-expression of the Zn-finger transcription factor (TF) CHE-1. Endogenous CHE-1 is expressed exclusively in two head neurons and is required to specify the glutamatergic ASE neurons fate, which can easily be visualized by the gcy-5prom::gfp reporter. A trans gene containing the heat-shock promoter-driven che-1 gene expression construct allows broad mis-expression of CHE-1 in the entire animal upon heat-shock treatment. The combination of RNAi against the chromatin-regulating factor LIN-53 and heat-shock-induced che-1 over-expression leads to reprogramming of germ cell into ASE neuron-like cells. We describe here the specific RNAi procedure and appropriate conditions for heat-shock treatment of transgenic animals in order to successfully induce germ cell to neuron conversion.

Application of RNAi and Heat-shock-induced Transcription Factor Expression to Reprogram Germ Cells to Neurons in C. elegans

This protocol describes how to study cellular processes during cell fate conversion in Caenorhabditis elegans in vivo. Using transgenic animals, allowing heat-shock promoter-driven overexpression of the neuron fate-inducing transcription factor CHE-1 and RNAi-mediated depletion of the chromatin-regulating factor LIN-53 germ cell to neuron reprogramming can be observed in vivo.

Studying the cell biological processes during converting the identities of specific cell types provides important insights into mechanism that maintain ...

CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer

Brain malformation is often caused by genetic mutations. Deciphering the mutations in patient-derived tissues has identified potential causative factors of the diseases. To validate the contribution of a dysfunction of the mutated genes to disease development, the generation of animal models carrying the mutations is one obvious approach. While germline genetically engineered mouse models (GEMMs) are popular biological tools and exhibit reproducible results, it is restricted by time and costs. Meanwhile, non-germline GEMMs often enable exploring gene function in a more feasible manner. Since some brain diseases (e.g., brain tumors) appear to result from somatic but not germline mutations, non-germline chimeric mouse models, in which normal and abnormal cells coexist, could be helpful for disease-relevant analysis. In this study, we report a method for the induction of CRISPR-mediated somatic mutations in the cerebellum. Specifically, we utilized conditional knock-in mice, in which Cas9 and GFP are chronically activated by the CAG (CMV enhancer/chicken &#223;-actin) promoter after Cre-mediated recombination of the genome. The self-designed single-guide RNAs (sgRNAs) and the Cre recombinase sequence, both encoded in a single plasmid construct, were delivered into cerebellar stem/progenitor cells at an embryonic stage using in utero electroporation. Consequently, transfected cells and their daughter cells were labeled with green fluorescent protein (GFP), thus facilitating further phenotypic analyses. Hence, this method is not only showing electroporation-based gene delivery into embryonic cerebellar cells but also proposing a novel quantitative approach to assess CRISPR-mediated loss-of-function phenotypes.

CRISPR-mediated Loss of Function Analysis in Cerebellar Granule Cells Using In Utero Electroporation-based Gene Transfer

Conventional loss-of-function studies of genes using knockout animals have often been costly and time-consuming. Electroporation-based CRISPR-mediated somatic mutagenesis is a powerful tool to understand gene functions in vivo. Here, we report a method to analyze knockout phenotypes in proliferating cells of the cerebellum.

Brain malformation is often caused by genetic mutations. Deciphering the mutations in patient-derived tissues has identified potential causative factors ...

Visualizing the Node and Notochordal Plate In Gastrulating Mouse Embryos Using Scanning Electron Microscopy and Whole Mount Immunofluorescence

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is the formation of the transient organizers, the node and notochordal plate, from cells that have passed through the primitive streak. The proper formation of these signaling centers is essential for the development of the body plan and techniques to visualize them are of high interest to mouse developmental biologists. The node and notochordal plate lie on the ventral surface of gastrulating mouse embryos around embryonic day (E) 7.5 of development. The node is a cup-shaped structure whose cells possess a single slender cilium each. The proper subcellular localization and rotation of the cilia in the node pit determines left-right asymmetry. The notochordal plate cells also possess single cilia albeit shorter than those of the node cells. The notochordal plate forms the notochord which acts as an important signaling organizer for somitogenesis and neural patterning. Because the cells of the node and notochordal plate are transiently present on the surface and possess cilia, they can be visualized using scanning electron microscopy (SEM). Among other techniques used to visualize these structures at the cellular level is whole mount immunofluorescence (WMIF) using the antibodies against the proteins that are highly expressed in the node and notochordal plate. In this report, we describe our optimized protocols to perform SEM and WMIF of the node and notochordal plate in developing mouse embryos to help in the assessment of tissue shape and cellular organization in wild-type and gastrulation mutant embryos.

The node and notochordal plate are transient signaling organizers in developing mouse embryos that can be visualized using several techniques. Here, we describe in detail how to perform two of the techniques to study their structure and morphogenesis: 1) scanning electron microscopy (SEM); and 2) whole mount immunofluorescence (WMIF).

The post-implantation mouse embryo undergoes major shape changes after the initiation of gastrulation and morphogenesis. A hallmark of morphogenesis is ...

Assessment of Ultrastructural Neuroplasticity Parameters After In Utero Transduction of the Developing Mouse Brain and Spinal Cord

The present study combines in utero transduction with transmission electron microscopy (TEM) aiming at a precise morphometrical analysis of ultrastructural parameters in unambiguously identified topographical structures, affected by a protein of interest that is introduced into the organism via viral transfer. This combined approach allows for a smooth transition from macrostructural to ultrastructural identification by following topographical navigation maps in a tissue atlas. High-resolution electron microscopy of the in-utero-transduced tissue reveals the fine ultrastructure of the neuropil and its plasticity parameters, such as cross-sectioned synaptic bouton areas, the number of synaptic vesicles and mitochondria within a bouton profile, the length of synaptic contacts, cross-sectioned axonal areas, the thickness of myelin sheaths, the number of myelin lamellae, and cross-sectioned areas of mitochondria profiles. The analysis of these parameters reveals essential insights into changes of ultrastructural plasticity in the areas of the nervous system that are affected by the viral transfer of the genetic construct. This combined method can not only be used for studying the direct effect of genetically engineered biomolecules and/or drugs on neuronal plasticity but also opens the possibility to study the in utero rescue of neuronal plasticity (e.g., in the context of neurodegenerative diseases).

The combination of transmission electron microscopy and in utero transduction is a powerful approach for studying morphological changes in the fine ultrastructure of the nervous system during development. This combined method allows deep insights into changes in structural details underlying neuroplasticity with respect to their topographical representation.

The present study combines in utero transduction with transmission electron microscopy (TEM) aiming at a precise morphometrical analysis of ...

Controlled Cortical Impact Model of Mouse Brain Injury with Therapeutic Transplantation of Human Induced Pluripotent Stem Cell-Derived Neural Cells

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. Disease pathology due to TBI progresses from the primary mechanical insult to secondary injury processes, including apoptosis and inflammation. Animal modeling has been valuable in the search to unravel injury mechanisms and evaluate potential neuroprotective therapies. This protocol describes the controlled cortical impact (CCI) model of focal, open-head TBI. Specifically, parameters for producing a mild unilateral cortical injury are described. Behavioral consequences of CCI are analyzed using the adhesive tape removal test of bilateral sensorimotor integration. Regarding experimental therapy for TBI pathology, this protocol also illustrates a process for transplanting cultured cells into the brain. Neural cell cultures derived from human induced pluripotent stem cells (hiPSCs) were chosen for their potential to show superior functional restoration in human TBI patients. Chronic survival of hiPSCs in the host mouse brain tissue is detected using a modified DAB immunohistochemical process.

This protocol demonstrates methodologies for a mouse model of open-skull traumatic brain injury and transplantation of cultured human induced pluripotent stem cell-derived cells into the injury site. Behavioral and histologic tests of outcomes from these procedures are also described in brief.

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. Disease pathology due to TBI progresses from the primary mechanical ...