Name: in vivo photolabeling of cells in the colon to assess migratory potential of hematopoietic cells in neonatal mice
Uploaded: 2018-08-10T14:45:00
Description: Watch this Scientific Journal Video about In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice at JoVE.com

Nitya Jain was supported by an NIH/NIAID Career Transition Award 1K22AI116661-01.

All animal procedures were performed with the approval of and in compliance with the Institutional Animal Care and Use Committee (IACUC) at Massachusetts General Hospital.
CAUTION: This protocol involves the use of a class 3b laser (LG3). LG3 laser safety goggles must always be used when operating this laser. Appropriate training and safety guidelines must be followed to avoid the risk of injury.
1. Design and Assembly of Laser
<ol>
	<li>Connect the light-emitting...

<ol>
	<li>Maynard, C. L., Elson, C. O., Hatton, R. D., Weaver, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reciprocal+interactions+of+the+intestinal+microbiota+and+immune+system.">Reciprocal interactions of the intestinal microbiota and immune system.</a> Nature. 489, 231-241 (2012).</li><li>Paun, A., Yau, C., Danska, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Influence+of+the+Microbiome+on+Type+1+Diabetes.">The Influence of the Microbiome on Type 1 Diabetes.</a> Journal of Immunology. 198, 590-595 (2017).</li><li>Mathis, D., Benoist, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microbiota+and+autoimmune+disease:+the+hosted+self.">Microbiota and autoimmune disease: the hosted self.</a> Cell Host Microbe. 10, 297-301 (2011).</li><li>Kollmann, T. R., Kampmann, B., Mazmanian, S. K., Marchant, A., Levy, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protecting+the+Newborn+and+Young+Infant+from+Infectious+Diseases:+Lessons+from+Immune+Ontogeny.">Protecting the Newborn and Young Infant from Infectious Diseases: Lessons from Immune Ontogeny.</a> Immunity. 46, 350-363 (2017).</li><li>Jain, N., Walker, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diet+and+host-microbial+crosstalk+in+postnatal+intestinal+immune+homeostasis.">Diet and host-microbial crosstalk in postnatal intestinal immune homeostasis.</a> Nature Reviews in Gastroenterology and Hepatology. 12, 14-25 (2015).</li><li>Mowat, A. M., Agace, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+specialization+within+the+intestinal+immune+system.">Regional specialization within the intestinal immune system.</a> Nature Reviews in Immunology. 14, 667-685 (2014).</li><li>Macpherson, A. J., Uhr, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Induction+of+protective+IgA+by+intestinal+dendritic+cells+carrying+commensal+bacteria.">Induction of protective IgA by intestinal dendritic cells carrying commensal bacteria.</a> Science. 303, 1662-1665 (2004).</li><li>Mowat, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomical+basis+of+tolerance+and+immunity+to+intestinal+antigens.">Anatomical basis of tolerance and immunity to intestinal antigens.</a> Nature Reviews in Immunology. 3, 331-341 (2003).</li><li>Diehl, G. E., 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=Microbiota+restricts+trafficking+of+bacteria+to+mesenteric+lymph+nodes+by+CX(3)CR1(hi)+cells.">Microbiota restricts trafficking of bacteria to mesenteric lymph nodes by CX(3)CR1(hi) cells.</a> Nature. 494 (3), 116-120 (2013).</li><li>Pham, A. H., McCaffery, J. M., Chan, 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=Mouse+lines+with+photo-activatable+mitochondria+to+study+mitochondrial+dynamics.">Mouse lines with photo-activatable mitochondria to study mitochondrial dynamics.</a> Genesis. 50, 833-843 (2012).</li><li>Conway, K. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ATG5+regulates+plasma+cell+differentiation.">ATG5 regulates plasma cell differentiation.</a> Autophagy. 9, 528-537 (2013).</li><li>Buzoni-Gatel, D., Lepage, A. C., Dimier-Poisson, I. H., Bout, D. T., Kasper, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adoptive+transfer+of+gut+intraepithelial+lymphocytes+protects+against+murine+infection+with+Toxoplasma+gondii.">Adoptive transfer of gut intraepithelial lymphocytes protects against murine infection with Toxoplasma gondii.</a> Journal of Immunology. 158, 5883-5889 (1997).</li><li>Guo, X., Muite, K., Wroblewska, J., Fu, Y. X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Purification+and+Adoptive+Transfer+of+Group+3+Gut+Innate+Lymphoid+Cells.">Purification and Adoptive Transfer of Group 3 Gut Innate Lymphoid Cells.</a> Methods in Molecular Biology. 1422, 189-196 (2016).</li><li>Morton, A. 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=Endoscopic+photoconversion+reveals+unexpectedly+broad+leukocyte+trafficking+to+and+from+the+gut.">Endoscopic photoconversion reveals unexpectedly broad leukocyte trafficking to and from the gut.</a> Proceedings of the National Academy of Sciences of the United States of America. 111, 6696-6701 (2014).</li></ol>

The identification and characterization of cells that interact with and are influenced by the microbiota in the colon are important and should facilitate understanding of how information from the mucosal microenvironment is relayed to the rest of the body. One method for studying gut-related cell migration requires the isolation of gut-associated cells followed by an adoptive transfer into recipient mice to determine their tissue-homing patterns and function12,13...

The mammalian gastrointestinal tract harbors hundreds of species of bacteria that exist in a symbiotic relationship with the host1. The immune cells present in the local milieu enforce a peaceful coexistence with these microbes and establish a protective barrier against pathogen invasions. Thus, bi-directional interactions between the immune cells and the microbiota are critical to establish a commensal community that educates the host immune system and sets the threshold for immune reactivity to pathogens. Changes in the microbial composition, or dysbiosis, can disturb the immune homeostasis and perturb regulatory circuits that restrain intestinal inflammations leading to immune-mediated diseases such as Type 1 Diabetes and IBD2,3.
The period immediately after birth is a unique developmental window during which the intestinal microbial communities begin to establish at the same time the immune system matures4. The postnatal microbiota is not stable, with shifts in the community composition occurring naturally and frequently5. The immune cells that interact with the microbiota reside in two distinct anatomical locations in the intestine - the lamina propria and the intestinal epithelium6. Numerous types of immune cells are present in the intestine, including lymphocytes (such as T cells, B cells, and innate lymphoid cells) as well as myeloid cells (which include dendritic cells, monocytes, and macrophages). These cells, also known as hematopoietic cells, perform a multitude of functions that preserve the intestinal barrier and maintain homeostasis.
In addition to their regulatory functions at intestinal sites, immune cells of the mucosa may also carry microbial messages to the extra-intestinal sites to regulate systemic immunity7,8,9. This is an area of growing research interest and highlights the need for methods to identify immune cells that migrate out of intestinal tissues in order to probe their function. The protocol reported here utilizes a commercially available mouse model in which a photoconvertible fluorescent protein is exploited to label cells. PhAMexcised mice ubiquitously express a green fluorescent Dendra2 protein that is irreversibly switched to red fluorescence upon activation by ultraviolet (UV) light10. Using a fiber optic cannula to deliver 405 nm light into the colon of newborn mice, we demonstrate that photoconverted hematopoietic cells, which have originated in or transited through the colon can be found in the spleen.

<table border="0" cellpadding="0" cellspacing="0" style="width:873px;" width="874">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:873px;">Laser</td>
			<td style="width:201px;"></td>
			<td style="width:167px;"></td>
			<td style="width:247px;"></td>
		</tr>
		<tr height="168">
			<td height="168" style="height:168px;width:259px;">Light Emitting Diode (LED)</td>
			<td style="width:201px;">THORLABS</td>
			<td style="width:167px;">M405FP1</td>
			<td style="width:247px;">CAUTION: this is a Class 3b laser. Safety goggles must be worn when using the laser. It emits a 405 nm wavelength with a current of 1400 mA. It is fiber-coupled. It accepts SMA connector. https://www.thorlabs.com/thorproduct.cfm?partnumber=M405FP1</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:259px;">LED driver</td>
			<td style="width:201px;">THORLABS</td>
			<td style="width:167px;">LEDD1B</td>
			<td style="width:247px;">Drives a constant current of 1200 mA through the laser. https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=2616</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:259px;">Optogenetics patch cable</td>
			<td style="width:201px;">THORLABS</td>
			<td style="width:167px;">M87L01</td>
			<td style="width:247px;">1 m long cable with an SMA connector. https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=11405&#38;pn=M87L01#11454</td>
		</tr>
		<tr height="147">
			<td height="147" style="height:147px;width:259px;">Fiber optic cannula</td>
			<td style="width:201px;">Doric lenses&#160;</td>
			<td style="width:167px;">MFC_480/500-0.5_5mm_ZF1.25_C45</td>
			<td style="width:247px;">5 mm long cannula with an outer diameter of 500 &#181;m and an inner diameter of 480 &#181;m. The NA value is 0.5. The ferrule is zirconia, 1.25 mm OD. https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=6036</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">Power supply</td>
			<td style="width:201px;">THORLABS</td>
			<td style="width:167px;">KPS101</td>
			<td style="width:247px;">Supplies 15 V with a current of 2.4 A https://www.thorlabs.com/search/thorsearch.cfm?search=KPS101</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:259px;">LG3 laser safety goggles&#160;</td>
			<td style="width:201px;">THORLABS</td>
			<td style="width:167px;">LG3</td>
			<td style="width:247px;">Orange lenses with 47% visible light transmission https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=762&#38;pn=LG3#2523</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;">Red light&#160;</td>
			<td>Electron Microscopy Sciences</td>
			<td>74327-10</td>
			<td style="width:247px;">15 W lamp https://us.vwr.com/store/product/12360027/paterson-safelight-electron-microscopy-sciences</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:873px;">Intestinal cell isolation</td>
			<td style="width:201px;"></td>
			<td style="width:167px;"></td>
			<td style="width:247px;"></td>
		</tr>
		<tr height="168">
			<td height="168" style="height:168px;width:259px;">Isoflurane</td>
			<td style="width:201px;">Patterson Veterinary</td>
			<td style="width:167px;">07-893-1389</td>
			<td style="width:247px;">CAUTION: inhalation of this anesthetic may cause dizziness, drowsiness, or even unconsciousness. This anesthetic should be used in a Class II hood.&#160; https://www.pattersonvet.com/Supplies/ProductFamilyDetails/PIF_762328?carouselPageNumber=3</td>
		</tr>
		<tr height="147">
			<td height="147" style="height:147px;width:259px;">1X HBSS</td>
			<td style="width:201px;">Gibco</td>
			<td style="width:167px;">14025076</td>
			<td style="width:247px;">Ca/Mg free https://www.fishersci.com/shop/products/gibco-hbss-calcium-magnesium-no-phenol-red-4/14025076?searchHijack=true&#38;searchTerm=14025076&#38;searchType=RAPID&#38;matchedCatNo=14025076</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Calf Serum</td>
			<td style="width:201px;">Hyclone AZM</td>
			<td style="width:167px;">197696</td>
			<td></td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:259px;">EDTA</td>
			<td style="width:201px;">Invitrogen</td>
			<td style="width:167px;">15575020</td>
			<td style="width:247px;">0.5 M concentration https://www.thermofisher.com/order/catalog/product/15575020?SID=srch-srp-15575020</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:259px;">DTT</td>
			<td style="width:201px;">Sigma</td>
			<td style="width:167px;">10197777001</td>
			<td style="width:247px;">CAUTION: harmful if swallowed and causes skin irritation. 1 M concentration https://www.sigmaaldrich.com/catalog/product/roche/dttro?lang=en&#38;region=US</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:259px;">HEPES</td>
			<td style="width:201px;">Gibco</td>
			<td style="width:167px;">15630080</td>
			<td style="width:247px;">1 M concentration https://www.thermofisher.com/order/catalog/product/15630080?SID=srch-hj-15630080</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:259px;">Petri dish</td>
			<td style="width:201px;">Corning</td>
			<td style="width:167px;">353004</td>
			<td style="width:247px;">https://www.fishersci.com/shop/products/falcon-easy-grip-tissue-culture-dishes-2/08772f?searchHijack=true&#38;searchTerm=08772F&#38;searchType=RAPID&#38;matchedCatNo=08772F</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">70 micron cell strainer</td>
			<td style="width:201px;">Falcon</td>
			<td style="width:167px;">352350</td>
			<td style="width:247px;">https://www.fishersci.com/shop/products/falcon-cell-strainers-4/087712</td>
		</tr>
		<tr height="168">
			<td height="168" style="height:168px;width:259px;">Micro magnetic stir bar</td>
			<td style="width:201px;">Fisherbrand</td>
			<td style="width:167px;">1451364</td>
			<td style="width:247px;">Rinse in 70% ethanol after each use. Rinse several times in distilled water prior to each use. The bar is 8 mm long with an octagonal shape. https://www.fishersci.com/shop/products/fisherbrand-octagonal-magnetic-stir-bars-12/1451364#?keyword=1451364</td>
		</tr>
		<tr height="168">
			<td height="168" style="height:168px;width:259px;">Magnetic stir plate</td>
			<td style="width:201px;">Corning Laboratory Stirrers</td>
			<td style="width:167px;">440826</td>
			<td style="width:247px;">https://www.coleparmer.com/i/corning-440826-nine-position-stirrer-120-vac-60-hz/8430420?PubID=UX&#38;persist=true&#38;ip=no&#38;gclid=CjwKCAiAqbvTBRAPEiwANEkyCLPLrWABXmOUI0QE53NLV0Owxlcs2V1K6rWbRPOwlcVVDq000FBiQxoCqQAQAvD_BwE</td>
		</tr>
		<tr height="147">
			<td height="147" style="height:147px;width:259px;">Collagenase</td>
			<td style="width:201px;">Roche</td>
			<td style="width:167px;">5401020001</td>
			<td style="width:247px;">https://www.sigmaaldrich.com/catalog/product/roche/05401020001?lang=en&#38;region=US&#38;gclid=CjwKCAiAjuPRBRBxEiwAeQ2QPhE44qlvxjmo1PYu3zCas3w-_d6P9gKjXW82-c1EOm6NjPHCc5WuixoC_0IQAvD_BwE</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">DNase I</td>
			<td style="width:201px;">Sigma</td>
			<td style="width:167px;">10104159001</td>
			<td style="width:247px;">https://www.sigmaaldrich.com/catalog/product/roche/10104159001?lang=en&#38;region=US</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">1X PBS</td>
			<td style="width:201px;">Gibco</td>
			<td style="width:167px;">20012-027</td>
			<td style="width:247px;">https://www.thermofisher.com/order/catalog/product/20012027?SID=srch-hj-20012-027</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:259px;">Pipet aid</td>
			<td style="width:201px;">Thermo Scientific</td>
			<td style="width:167px;">14387165</td>
			<td style="width:247px;">https://www.fishersci.com/shop/products/s1-pipette-fillers/14387165#?keyword=14387165</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">10 mL serological pipet</td>
			<td style="width:201px;">Falcon</td>
			<td style="width:167px;">357530</td>
			<td style="width:247px;">https://www.fishersci.com/shop/products/falcon-serological-pipets-bulk-pack-5/p-163659</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">25 mL serological pipet</td>
			<td style="width:201px;">Falcon</td>
			<td style="width:167px;">357515</td>
			<td style="width:247px;">https://www.fishersci.com/shop/products/falcon-serological-pipets-bulk-pack-5/p-163659</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">15 mL conical centrifuge tube</td>
			<td style="width:201px;">Thermo Scientific</td>
			<td style="width:167px;">339651</td>
			<td style="width:247px;">https://www.thermofisher.com/order/catalog/product/339650</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:259px;">50 mL conical centrifuge tube</td>
			<td style="width:201px;">Thermo Scientific</td>
			<td style="width:167px;">339653</td>
			<td style="width:247px;">https://www.thermofisher.com/order/catalog/product/339650</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:873px;">Single cell suspension</td>
			<td style="width:201px;"></td>
			<td style="width:167px;"></td>
			<td style="width:247px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">Eppendorf tubes</td>
			<td style="width:201px;">Seal-Rite</td>
			<td style="width:167px;">1615-5500</td>
			<td style="width:247px;">Holds 1.5 mL. https://www.usascientific.com/Seal-Rite-1.5-ml-tube.aspx</td>
		</tr>
		<tr height="105">
			<td height="105" style="height:105px;width:259px;">Tissue homogenizer&#160;</td>
			<td style="width:201px;">Kimble</td>
			<td>K7495400000</td>
			<td style="width:247px;">Requires 2 AA batteries. https://www.fishersci.com/shop/products/kontes-pellet-pestle-cordless-motor-cordless-motor/k7495400000</td>
		</tr>
		<tr height="126">
			<td height="126" style="height:126px;width:259px;">Homogenizer tips&#160;</td>
			<td style="width:201px;">Kimble</td>
			<td style="width:167px;">7495210590</td>
			<td style="width:247px;">Plastic, 0.5 mL tips https://www.fishersci.com/shop/products/kimble-chase-kontes-pellet-pestle-14/k7495210590#?keyword=7495210590</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">ACK lysing buffer</td>
			<td style="width:201px;">Gibco</td>
			<td style="width:167px;">A10492-01</td>
			<td style="width:247px;">https://www.thermofisher.com/order/catalog/product/A1049201?SID=srch-hj-A10492-01</td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:259px;">40 micron cell strainer</td>
			<td style="width:201px;">Falcon</td>
			<td style="width:167px;">08-771-1</td>
			<td style="width:247px;">https://www.fishersci.com/shop/products/falcon-cell-strainers-4/087711</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:873px;">Antibodies</td>
			<td style="width:201px;"></td>
			<td style="width:167px;"></td>
			<td style="width:247px;"></td>
		</tr>
		<tr height="147">
			<td height="147" style="height:147px;width:259px;">BV786 anti-mouse CD45&#160;</td>
			<td style="width:201px;">BD</td>
			<td style="width:167px;">564225</td>
			<td style="width:247px;">Clone 3O-F11 https://www.bdbiosciences.com/us/reagents/research/antibodies-buffers/immunology-reagents/anti-mouse-antibodies/cell-surface-antigens/bv786-rat-anti-mouse-cd45-30-f11/p/564225</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Live/Dead</td>
			<td>Invitrogen</td>
			<td>L34962</td>
			<td style="width:247px;">https://www.thermofisher.com/order/catalog/product/L34962</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:259px;">Other</td>
			<td style="width:201px;"></td>
			<td style="width:167px;"></td>
			<td style="width:247px;"></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;">Razor blades</td>
			<td>VWR</td>
			<td>55411-050</td>
			<td style="width:247px;">Use for decapitation. https://us.vwr.com/store/product/4548306/vwr-razor-blades</td>
		</tr>
	</tbody>
</table>

in vivo photolabeling of cells in the colon to assess migratory potential of hematopoietic cells in neonatal mice

Enteric bacterial communities are established early in life and influence immune cell development and function. The neonatal microbiota is susceptible to numerous external influences including antibiotics use and diet, which impacts susceptibility to autoimmune and inflammatory diseases. Disorders such as Inflammatory Bowel Disease (IBD) are characterized by a massive influx of immune cells to the intestines. However, immune cells conditioned by the microbiota may additionally emigrate out of the intestines to influence immune responses at extra-intestinal sites. Thus, there is a need to identify and characterize cells that may carry microbial messages from the intestines to distal sites. Here, we describe a method to label cells in the colon of newborn mice in vivo that enables their identification at extra-intestinal sites after migration.

A fiber-optic cable was used to deliver 405 nm light into the colons of 2-day old PhAMexcised mice. In previous experiments, a 30 s exposure was determined to give a maximal photoconversion of colon cells with minimal cytotoxicity (Figure 1A). Therefore, sequential 30 s exposures of different segments of the colon were carried out as described in the protocol. Following the laser exposure, the mice were immediately euthanized, and ...

Watch this Scientific Journal Video about In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice at JoVE.com

In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice

The protocol described here utilizes a photolabeling approach in newborn mice to specifically identify immune cells that emigrate from the colon to extra-intestinal sites. This strategy will be useful to study host-microbiome interactions in early life.

In Vivo Photolabeling of Cells in the Colon to Assess Migratory Potential of Hematopoietic Cells in Neonatal Mice

Enteric bacterial communities are established early in life and influence immune cell development and function. The neonatal microbiota is susceptible to ...

This method can help answer key questions in the mucosal immunology field regarding neonatal host immune microbiome interactions such as do cells carry microbial messages, and if so which cells are they? The main advantage of this technique is that it non-specifically an irreversibly labels colon resident cells in infant mice, enabling us to determine their trafficking patterns to extra-intestinal sites. To assemble the laser, connect the light-emitting diode, or LED to the LED driver via the four-pin M8 connector cable of the LED and carefully tighten the screw to fasten the connection.Hold the connector opening of the LED up to the light to ensure that there are no visible obstructions. Insert the optogenetics patch cable into the opening. Insert the cannula into either end of the connector sleeve.Then attach the other end of the connector sleeve to the end of the patch cable, connecting the fiberoptic cannula to the fiberoptic patch cable. Use the continuous adjustment knob to set the LED driver to the continuous wave mode at zero, and the current limit set to 1.2 amps. When the laser is ready, plug the LED driver into a power source in a dark location.Use one hand to gently scruff the back of an anesthetized day 10 to 12 postnatal mouse with the index finger and thumb. Turn over the animal to expose the abdomen, and secure the tail between the ring and little fingers. Use the other hand to remove the protective cap from the cannula, and gently insert the fiberoptic cannula through the anus, into the colon, so that all five millimeters of the optical fiber are inside the mouse, maintaining the long axis of the cannula parallel to the mouse's midline.The design of the cannula including its flexibility, diameter, and length is critical to the success of this procedure. The neonatal pup is very fragile and great care must be taken to avoid perforating the colon. Wearing safety goggles, increase the laser current to the maximum value and confirm the presence of UV light by looking at the translucent abdomen of the animal.Withdraw the cannula approximately one millimeter every 30 seconds to maximize the luminal area exposed to the light. After two minutes total of UV light exposure, slowly remove the cannula from the mouse and turn off the laser. After recovering from anesthesia, return the mouse to the home cage.To harvest the intestinal lymphocytes, use clean forceps and scissors to open the abdomen, and reflect the intestines to one side to expose the colon. To remove the whole colon, first transect the tissue just distal to the cecum, and firmly grasping the colon with forceps, use scissors to cut through the urethra to the rectum. Then cut the colon as close to the anus as possible, and remove the entire colon from the abdominal cavity.Use forceps to push the contents out of the colon onto a dry paper towel. And transfer the clean colon onto the lid of a tissue culture dish. Use razor blades to finely chop the sample, and transfer the resulting paste into a cell strainer set in a Petri dish containing 10 milliliters of cold Hank's Balanced Buffer Solution supplemented with calf serum, or HBSS-CS.Add a clean eight millimeter long magnetic stir bar to the strainer and place the dish on a nine-position magnetic stirrer plate with a magnetic stir bar speed set to 800 RPM. After a five-minute incubation at room temperature, discard the buffer, and repeat the wash with 10 milliliters of HBSS-CS. Dissociate the epithelial cells with 10 milliliters of pre-warmed epithelial strip buffer and stir the cells at 800 RPM for 30 minutes in a 37-degree Celsius incubator.At the end of the incubation, transfer the enriched intestinal epithelial fraction into a 15 milliliter tube for centrifugation. And re-suspend the pellet in one milliliter of FACS buffer on ice. Next, wash the remaining lamina propria tissue in the strainer two times with HBSS-CS as just demonstrated, followed by two incubations in 10 milliliters of wash buffer supplemented with EDTA for 15 minutes at 37 degrees Celsius with stirring.Then wash the sample two more times with HBSS-CS, followed by a third incubation in 10 milliliters of EDTA-free wash buffer for 10 minutes at room temperature without stirring. At the end of the incubation wash the sample two more times with HBSS-CS, and digest the remaining lamina propria tissue in the cell strainer with 10 more milliliters of EDTA-wash buffer supplemented with Dnase I and collagenase with stirring at 800 RPM for 45 minutes at 37 degrees Celsius. At the end of the digestion filter the enzyme solution through a new strainer into a 50 milliliter conical tube and neutralize the collagenase activity with 20 milliliters of cold wash medium.Collect the lamina propria cells by centrifugation. And re-suspend the lamina propria lymphocyte pellet in one milliliter of FACS buffer. Then combine the intestinal epithelial lymphocytes and the lamina propria lymphocyte fractions, and stain the cells with the appropriate fluorescents conjugated antibodies of interest for flow cytometric analysis.A 30-second laser light exposure delivers a maximal photo conversion of colon cells with a minimal cytotoxicity. No fluorescents activated cells are detected in the colons of unlasered mice, while 405 nanometers of light exposure results in distinct dendra-r positive cell populations in both the CD45 negative and CD45 positive cell compartments. Of note, no background labeling is observed in the spleen, suggesting that the intracolonic laser beam does not penetrate enough to photolabel cells in extraintestinal sites.In this representative experiment, the migration of photoconverted intestinal cell migration from the colon to the spleen was evaluated with only CD4 positive cells identified three to five days after laser light exposure, consistent with the theory that CD45 negative cells within the colon are primarily epithelial and structural cells. Once mastered, the light exposure steps can be performed in approximately five minutes per mouse, while the entire sample collection and analysis takes about nine hours to be completed. After watching this video you should have a good understanding of how to label cells in the colons of newborn mice and to use flow cytometry to identify the labeled cells in the spleen after their migration.Don't forget that working with ultraviolet light and animal anesthetics can be extremely hazardous. Precautions such as wearing safety goggles and using an appropriate scavenging system should always be taken while working with these materials.

in-vivo-photolabeling-cells-colon-to-assess-migratory-potential

Research

JoVE Journal

Medicine

A Strategy to Identify de Novo Mutations in Common Disorders such as Autism and Schizophrenia

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, the de novo mutation rate in humans is relatively high, so new mutations are generated at a high frequency in the population. However, de novo mutations have not been reported in most common diseases. Mutations in genes leading to severe diseases where there is a strong negative selection against the phenotype, such as lethality in embryonic stages or reduced reproductive fitness, will not be transmitted to multiple family members, and therefore will not be detected by linkage gene mapping or association studies. The observation of very high concordance in monozygotic twins and very low concordance in dizygotic twins also strongly supports the hypothesis that a significant fraction of cases may result from new mutations. Such is the case for diseases such as autism and schizophrenia. Second, despite reduced reproductive fitness1 and extremely variable environmental factors, the incidence of some diseases is maintained worldwide at a relatively high and constant rate. This is the case for autism and schizophrenia, with an incidence of approximately 1% worldwide. Mutational load can be thought of as a balance between selection for or against a deleterious mutation and its production by de novo mutation. Lower rates of reproduction constitute a negative selection factor that should reduce the number of mutant alleles in the population, ultimately leading to decreased disease prevalence. These selective pressures tend to be of different intensity in different environments. Nonetheless, these severe mental disorders have been maintained at a constant relatively high prevalence in the worldwide population across a wide range of cultures and countries despite a strong negative selection against them2. This is not what one would predict in diseases with reduced reproductive fitness, unless there was a high new mutation rate. Finally, the effects of paternal age: there is a significantly increased risk of the disease with increasing paternal age, which could result from the age related increase in paternal de novo mutations. This is the case for autism and schizophrenia3. The male-to-female ratio of mutation rate is estimated at about 4&#x2013;6:1, presumably due to a higher number of germ-cell divisions with age in males. Therefore, one would predict that de novo mutations would more frequently come from males, particularly older males4. A high rate of new mutations may in part explain why genetic studies have so far failed to identify many genes predisposing to complexes diseases genes, such as autism and schizophrenia, and why diseases have been identified for a mere 3% of genes in the human genome. Identification for de novo mutations as a cause of a disease requires a targeted molecular approach, which includes studying parents and affected subjects. The process for determining if the genetic basis of a disease may result in part from de novo mutations and the molecular approach to establish this link will be illustrated, using autism and schizophrenia as examples.

Molecular genetic strategy for finding de novo mutations causing common disorders such as autism and schizophrenia.

There are several lines of evidence supporting the role of de novo mutations as a mechanism for common disorders, such as autism and schizophrenia. First, ...

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. Despite the discovery of key regulators of uterine contractility, this process is still not fully understood. Transgenic mice provide an ideal model in which to study parturition. Previously, the only method to study uterine contractility in the mouse was ex vivo isometric tension recordings, which are suboptimal for several reasons. The uterus must be removed from its physiological environment, a limited time course of investigation is possible, and the mice must be sacrificed. The recent development of radiometric telemetry has allowed for longitudinal, real-time measurements of in vivo intrauterine pressure in mice. Here, the implantation of an intrauterine telemeter to measure pressure changes in the mouse uterus from mid-pregnancy until delivery is described. By comparing differences in pressures between wild type and transgenic mice, the physiological impact of a gene of interest can be elucidated. This technique should expedite the development of therapeutics used to treat myometrial disorders during pregnancy, including preterm labor.

Intrauterine Telemetry to Measure Mouse Contractile Pressure In Vivo

This manuscript provides a protocol for implanting telemeters in the mouse for the purpose of measuring intrauterine pressures during pregnancy.

A complex integration of molecular and electrical signals is needed to transform a quiescent uterus into a contractile organ at the end of pregnancy. ...

In Vivo Imaging and Tracking of Technetium-99m Labeled Bone Marrow Mesenchymal Stem Cells in Equine Tendinopathy

Recent advances in the application of bone marrow mesenchymal stem cells (BMMSC) for the treatment of tendon and ligament injuries in the horse suggest improved outcome measures in both experimental and clinical studies. Although the BMMSC are implanted into the tendon lesion in large numbers (usually 10 - 20 million cells), only a relatively small number survive (&#60;10%) although these can persist for up to 5 months after implantation. This appears to be a common observation in other species where BMMSC have been implanted into other tissues and it is important to understand when this loss occurs, how many survive the initial implantation process and whether the cells are cleared into other organs. Tracking the fate of the cells can be achieved by radiolabeling the BMMSC prior to implantation which allows non-invasive in vivo imaging of cell location and quantification of cell numbers.
This protocol describes a cell labeling procedure that uses Technetium-99m (Tc-99m), and tracking of these cells following implantation into injured flexor tendons in horses. Tc-99m is a short-lived (t1/2 of 6.01 hr) isotope that emits gamma rays and can be internalized by cells in the presence of the lipophilic compound hexamethylpropyleneamine oxime (HMPAO). These properties make it ideal for use in nuclear medicine clinics for the diagnosis of many different diseases. The fate of the labeled cells can be followed in the short term (up to 36 hr) by gamma scintigraphy to quantify both the number of cells retained in the lesion and distribution of the cells into lungs, thyroid and other organs. This technique is adapted from the labeling of blood leukocytes and could be utilized to image implanted BMMSC in other organs.

In Vivo Imaging and Tracking of Technetium-99m Labeled Bone Marrow Mesenchymal Stem Cells in Equine Tendinopathy

This protocol describes the radiolabeling of equine mesenchymal stem cells and their implantation into tendon injuries in the horse in order to determine cell survival and tissue distribution using gamma scintigraphy.

Recent advances in the application of bone marrow mesenchymal stem cells (BMMSC) for the treatment of tendon and ligament injuries in the horse suggest ...

Studying Pancreatic Cancer Stem Cell Characteristics for Developing New Treatment Strategies

Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor initiation, metastasis and resistance to radio- and chemotherapy. Here we describe a specific methodology for culturing primary human pancreatic CSCs as tumor spheres in anchorage-independent conditions. Cells are grown in serum-free, non-adherent conditions in order to enrich for CSCs while their more differentiated progenies do not survive and proliferate during the initial phase following seeding of single cells. This assay can be used to estimate the percentage of CSCs present in a population of tumor cells. Both size (which can range from 35 to 250 micrometers) and number of tumor spheres formed represents CSC activity harbored in either bulk populations of cultured cancer cells or freshly harvested and digested tumors 1,2. Using this assay, we recently found that metformin selectively ablates pancreatic CSCs; a finding that was subsequently further corroborated by demonstrating diminished expression of pluripotency-associated genes/surface markers and reduced in vivo tumorigenicity of metformin-treated cells. As the final step for preclinical development we treated mice bearing established tumors with metformin and found significantly prolonged survival. Clinical studies testing the use of metformin in patients with PDAC are currently underway (e.g., NCT01210911, NCT01167738, and NCT01488552). Mechanistically, we found that metformin induces a fatal energy crisis in CSCs by enhancing reactive oxygen species (ROS) production and reducing mitochondrial transmembrane potential. In contrast, non-CSCs were not eliminated by metformin treatment, but rather underwent reversible cell cycle arrest. Therefore, our study serves as a successful example for the potential of in vitro sphere formation as a screening tool to identify compounds that potentially target CSCs, but this technique will require further in vitro and in vivo validation to eliminate false discoveries.

Pancreatic cancer stem cells (CSCs) can be expanded in vitro using the anchorage-independent sphere culture technique, which represents a powerful tool to study CSC biology and can serve as the first step to develop novel CSC-targeting therapies. Here the methodology for expanding, analyzing and targeting of pancreatic CSCs is provided.

Pancreatic ductal adenocarcinoma (PDAC) contains a subset of exclusively tumorigenic cancer stem cells (CSCs) which have been shown to drive tumor ...

Injection of Syngeneic Murine Melanoma Cells to Determine Their Metastatic Potential in the Lungs

Approximately 90% of human cancer deaths are linked to metastasis. Despite the prevalence and relative harm of metastasis, therapeutics for treatment or prevention are lacking. We report a method for the establishment of pulmonary metastases in mice, useful for the study of this phenomenon. Tail vein injection of B57BL/6J mice with B16-BL6 is among the most used models for melanoma metastases. Some of the circulating tumor cells establish themselves in the lungs of the mouse, creating "experimental" metastatic foci. With this model it is possible to measure the relative effects of therapeutic agents on the development of cancer metastasis. The difference in enumerated lung foci between treated and untreated mice indicates the efficacy of metastases neutralization. However, prior to the investigation of a therapeutic agent, it is necessary to determine an optimal number of injected B16-BL6 cells for the quantitative analysis of metastatic foci. Injection of too many cells may result in an overabundance of metastatic foci, impairing proper quantification and overwhelming the effects of anti-cancer therapies, while injection of too few cells will hinder the comparison between treated and controls.

Metastasis plays a profound role in the virulence of cancer, accounting for an estimated 90% of deaths. We report a protocol for a metastatic melanoma model in mice that is useful for determining the efficacy of therapeutic agents against this clinical phenomenon.

Approximately 90% of human cancer deaths are linked to metastasis.  Despite the prevalence and relative harm of metastasis, therapeutics for treatment or ...

Myocardial Infarction in Neonatal Mice, A Model of Cardiac Regeneration

Myocardial infarction induced by coronary artery ligation has been used in many animal models as a tool to study the mechanisms of cardiac repair and regeneration, and to define new targets for therapeutics. For decades, models of complete heart regeneration existed in amphibians and fish, but a mammalian counterpart was not available. The recent discovery of a postnatal window during which mice possess regenerative capabilities has led to the establishment of a mammalian model of cardiac regeneration. A surgical model of mammalian cardiac regeneration in the neonatal mouse is presented herein. Briefly, postnatal day 1 (P1) mice are anesthetized by isoflurane and placed on an ice pad to induce hypothermia. After the chest is opened, and the left anterior descending coronary artery (LAD) is visualized, a suture is placed around the LAD to inflict myocardial ischemia in the left ventricle. The surgical procedure takes 10-15 min. Visualizing the coronary artery is crucial for accurate suture placement and reproducibility. Myocardial infarction and cardiac dysfunction are confirmed by triphenyl-tetrazolium chloride (TTC) staining and echocardiography, respectively. Complete regeneration 21 days post myocardial infarction is verified by histology. This protocol can be used to as a tool to elucidate mechanisms of mammalian cardiac regeneration after myocardial infarction.

This protocol describes a highly reproducible model of cardiac regeneration by surgical induction of myocardial infarction in the left ventricle of postnatal day 1 mice. The method involves induction of hypothermic anesthesia and ligation of the left anterior descending coronary artery.

Myocardial infarction induced by coronary artery ligation has been used in many animal models as a tool to study the mechanisms of cardiac repair and ...

Depletion of Mouse Cells from Human Tumor Xenografts Significantly Improves Downstream Analysis of Target Cells

The use of in vitro cell line models for cancer research has been a useful tool. However, it has been shown that these models fail to reliably mimic patient tumors in different assays1. Human tumor xenografts represent the gold standard with respect to tumor biology, drug discovery, and metastasis research 2-4. Tumor xenografts can be derived from different types of material like tumor cell lines, tumor tissue from primary patient tumors4 or serially transplanted tumors. When propagated in vivo, xenografted tissue is infiltrated and vascularized by cells of mouse origin. Multiple factors such as the tumor entity, the origin of xenografted material, growth rate and region of transplantation influence the composition and the amount of mouse cells present in tumor xenografts. However, even when these factors are kept constant, the degree of mouse cell contamination is highly variable.
Contaminating mouse cells significantly impair downstream analyses of human tumor xenografts. As mouse fibroblasts show high plating efficacies and proliferation rates, they tend to overgrow cultures of human tumor cells, especially slowly proliferating subpopulations. Mouse cell derived DNA, mRNA, and protein components can bias downstream gene expression analysis, next-generation sequencing, as well as proteome analysis 5. To overcome these limitations, we have developed a fast and easy method to isolate untouched human tumor cells from xenografted tumor tissue. This procedure is based on the comprehensive depletion of cells of mouse origin by combining automated tissue dissociation with the benchtop tissue dissociator and magnetic cell sorting. Here, we demonstrate that human target cells can be can be obtained with purities higher than 96% within less than 20 min independent of the tumor type.

Human tumor xenografts are vascularized and infiltrated by cells of mouse origin during the growth phase in vivo. To circumvent the bias caused by these contaminating cells during downstream analysis, we developed a method allowing for comprehensive depletion of all mouse cells by magnetic cell sorting.

The use of in vitro cell line models for cancer research has been a useful tool. However, it has been shown that these models fail to reliably mimic ...

Isolation of Endothelial Progenitor Cells from Healthy Volunteers and Their Migratory Potential Influenced by Serum Samples After Cardiac Surgery

Endothelial progenitor cells (EPCs) are recruited from the bone marrow under pathological conditions like hypoxia and are crucially involved in the neovascularization of ischemic tissues. The origin, classification and characterization of EPCs are complex; notwithstanding, two prominent sub-types of EPCs have been established: so-called &#34;early&#34; EPCs (subsequently referred to as early-EPCs) and late-outgrowth EPCs (late-EPCs). They can be classified by biological properties as well as by their appearance during in vitro culture. While &#34;early&#34; EPCs appear in less than a week after culture of peripheral blood-derived mononuclear cells in EC-specific media, late-outgrowth EPCs can be found after 2-3 weeks. Late-outgrowth EPCs have been recognized to be directly involved in neovascularization, mainly through their ability to differentiate into mature endothelial cells, whereas &#34;early&#34; EPCs express various angiogenic factors as endogenous cargo to promote angiogenesis in a paracrine manner. During myocardial ischemia/reperfusion (I/R), various factors control the homing of EPCs to regions of blood vessel formation.
Macrophage migration inhibitory factor (MIF) is a chemokine-like pro-inflammatory and ubiquitously expressed cytokine and was recently described to function as key regulator of EPCs migration at physiological concentrations1. Interestingly, MIF is stored in intracellular pools and can rapidly be released into the blood stream after several stimuli (e.g. myocardial infarction). 
This protocol describes a method for the reliable isolation and culture of early-EPCs from adult human peripheral blood based on CD34-positive selection with subsequent culture in medium containing endothelial growth factors on fibronectin-coated plates for use in in vitro migration assays against serum samples of cardiac surgical patients. Furthermore, the migratory influence of MIF on chemotaxis of EPCs compared to other well-known angiogenesis-stimulating cytokines is demonstrated.

Endothelial progenitor cells (EPCs) are crucially involved in the neovascularization of ischemic tissues. This method describes the isolation of human EPCs from peripheral blood, as well as the identification of their migratory potential against serum samples of cardiac surgical patients.

Endothelial progenitor cells (EPCs) are recruited from the bone marrow under pathological conditions like hypoxia and are crucially involved in the ...

In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice

Mitochondria are the powerhouses of cells and produce cellular energy in the form of ATP. Mitochondrial dysfunction contributes to biological aging and a wide variety of disorders including metabolic diseases, premature aging syndromes, and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Maintenance of mitochondrial health depends on mitochondrial biogenesis and the efficient clearance of dysfunctional mitochondria through mitophagy. Experimental methods to accurately detect autophagy/mitophagy, especially in animal models, have been challenging to develop. Recent progress towards the understanding of the molecular mechanisms of mitophagy has enabled the development of novel mitophagy detection techniques. Here, we introduce several versatile techniques to monitor mitophagy in human cells, Caenorhabditis elegans (e.g., Rosella and DCT-1/ LGG-1 strains), and mice (mt-Keima). A combination of these mitophagy detection techniques, including cross-species evaluation, will improve the accuracy of mitophagy measurements and lead to a better understanding of the role of mitophagy in health and disease.

In Vitro and In Vivo Detection of Mitophagy in Human Cells, C. Elegans, and Mice

Mitophagy, the process of clearing damaged mitochondria, is necessary for mitochondrial homeostasis and health maintenance. This article presents some of the latest mitophagy detection methods in human cells, Caenorhabditis elegans, and mice.

Mitochondria are the powerhouses of cells and produce cellular energy in the form of ATP. Mitochondrial dysfunction contributes to biological aging and a ...