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Method Article
Improved imaging technology is allowing three-dimensional imaging of organs during development. Here we describe a whole organ culture system that allows live imaging of the developing villi in the fetal mouse intestine.
Die meisten morphogenetische Prozesse in der fetalen Darm haben von Dünnschnitten von fixierten Gewebe entnommen worden, die Bereitstellung Schnappschüsse von Veränderungen über die Entwicklungsstadien. Dreidimensionale Informationen aus dünnen Serienschnitten kann eine Herausforderung sein, wegen der Schwierigkeit der Rekonstruktion Serienschnitte perfekt und die Aufrechterhaltung der richtigen Ausrichtung des Gewebes über Serienschnitte zu interpretieren. Jüngsten Erkenntnisse Grosse et al., 2011, die Bedeutung der dreidimensionalen Informationen für das Verständnis der Morphogenese der Entwicklungs Zotten des Darms 1. Dreidimensionale Rekonstruktion des einfach markierten Darmzellen zeigte, dass die Mehrheit der intestinalen Epithelzellen treten sowohl die apikale und basale Oberflächen. Weiterhin dreidimensionale Rekonstruktion des Aktin an der apikalen Oberfläche des Epithels zeigte, dass die Darmlumen kontinuierlich ist und dass die sekundäre Lumen ein Artefakt sectioning. Diese zwei Punkte, zusammen mit dem Nachweis der interkinetic Kernwanderung im Darmepithel, definiert die Entwicklungs Darmepithel als mehrreihigen Epithel und nicht wie bisher angenommen geschichtete 1. Die Fähigkeit, das Epithel dreidimensional beobachten war wegweisend für demonstriert diesen Punkt und die Neudefinition epithelialen Morphogenese in der fetalen Darm. Mit der Entwicklung der Mehrphotonen-Bildgebungstechnik und dreidimensionale Rekonstruktionssoftware, die Fähigkeit zu visualisieren intakt Entwicklungsorgane rasch verbessert. Zwei-Photonen-Anregung ermöglicht weniger schädliches Eindringen tiefer in Gewebe mit hoher Auflösung. Zwei-Photon-Imaging und 3D-Rekonstruktion der gesamten fötalen Mausdarm in Walton et al., 2012, half, das Muster der Zotten Auswuchs 2 definieren. Hier beschreiben wir eine ganze Organkultursystem, das ex vivo Entwicklung der Zotten und Erweiterungen dieser Kultur-System ermöglicht, damitder Darm dreidimensional in ihrer Entwicklung dargestellt werden.
Each intestinal villus is composed of two main tissue compartments: an epithelial surface layer and a mesenchymal core. The mouse small intestine is formed at embryonic day 10 when a sheet of endoderm closes and seals to form a tube of epithelium surrounded by mesenchymal cells3. This flat tube of epithelium undergoes rapid proliferation, growing both in length and girth and undergoes dramatic rearrangements involving dynamic cell shape changes1. At the same time, the surrounding mesenchyme also undergoes many developmental processes including the formation of the vascular plexus, differentiation of smooth muscle and recruitment of enteric neurons4. In the proximal small intestine at embryonic day 14.5, condensations (clusters) of Hedgehog- and PDGF-responsive cells begin to form adjacent to the epithelium2,5. Formation of mesenchymal clusters continues to spread along the length of the intestine so that they cover the entirety of the small intestine by embryonic day 16.52. As mesenchymal clusters form, the epithelial cells closest to the clusters begin to withdraw from the cell cycle, while the other epithelial cells continue to proliferate. Those cells directly above the mesenchymal cluster that have withdrawn from the cell cycle begin to change shape as the emerging villus buckles into the lumen. Further growth of the villus is driven in part by the continued proliferation of the epithelium between the emerging villi. The mesenchymal clusters remain tightly adhered to the epithelium of the growing villus and continue to express a variety of signaling molecules. The wave of villus emergence propagates along the length of the small intestine following the formation of mesenchymal clusters. As the intestine continues to grow and the intervillus region extends between emerging villi, new mesenchymal clusters form adjacent to the intervillus epithelium and further rounds of villus emergence and growth ensue6.
Synchronized development of the epithelium and mesenchyme is essential for villus morphogenesis. Signaling molecules are secreted from one layer to the other where receptors receive and transduce the signal message in order to coordinate development between the epithelium and mesenchyme. Mesenchymal clusters act as signaling centers and express a variety of developmental morphogens7-10. Disruption of cluster formation or pattern results in loss of villus emergence and pattern. Inhibition of PDGF signaling results in fewer clusters and fewer villi and those villi that do form are misshapen following the abnormal clusters11. Loss of Hedgehog signaling results in complete loss of cluster formation and failure of villus emergence2,12. Together, these data demonstrate that clusters coordinate development of the villus epithelium with its mesenchymal core.
Using this whole organ culture system, we are able to alter signaling involved in epithelial-mesenchymal cluster cross-talk to determine the role of those signals in villus morphogenesis. Two-photon confocal optical sectioning and reconstruction afford the ability to visualize cluster formation and villus emergence in three-dimensions and better understand the spatial relationships between the mesenchymal clusters and their overlying epithelium. Extending the culture system to four dimensions, we can capture z-stacks of developing clusters and villi over time and observe these interactions. Ultimately, the ability to follow villus development in this manner and observe changes that occur with altered signaling will revolutionize the understanding of epithelial mesenchymal interactions in villus morphogenesis.
HINWEIS: Alle Mäuse wurden mit human Protokolle, die von der University of Michigan Medical School Einheit für Labortiermedizin zugelassen und nach den Richtlinien der Universität Ausschuss für Nutzung und Pflege von Tieren behandelt.
1. Vollorgankultursystem
2. Imaging von Fest Darm
3. Live-Imaging von Whole Darm
Darm von fetuse geerntets nach E12.5, mit dem angeschlossenen Netz intakt gelassen, erfolgreich zu entwickeln Zotten in Kultur unter Verwendung der oben System. Daher ermöglicht diese ex vivo-System die Erfassung von lebenden z-Schnittbilder der Entwicklungs Darm, die eine dreidimensionale Ansicht der Morphogenese im Laufe der Zeit wieder aufgebaut werden kann.
Kultur ganzer fötaler Explantate Darm ermöglicht die Analyse der Lage, die Verteilung, und die Dauer der Signalmoleküle, die Darmentwicklung zu koordinieren, da dieses System ermöglicht die Bearbeitung der Signalisierungs pharmakologische Reagenzien oder rekombinante Proteine. Die Transwell-Kultursystem (1A, von Walton et al wiedergegeben., 2012) 2 stellt ein Luft-Flüssigkeits-Schnittstelle, die es ermöglicht, Wirkstoff-oder Protein getränkt Agarosekügelchen auf das Gewebe zu...
Die Dynamik und komplexe Gewebe-Wechselwirkungen der Entwicklungs Darm erfordert 3D-Visualisierung, um eine volle Anerkennung dieser morphogenetischen Ereignisse. Mit der Entwicklung der Imaging-Technologie, die Fähigkeit villus Morphogenese im Detail entwickelt / verbessert und mit ihr wird das Verständnis der räumlichen Kommunikation und Interaktion während der Organogenese stark verbessert zu prüfen.
Alternative Methoden zur Kultivierung ganze Darm wurden auch getestet worden, aber d...
The authors have no financial conflicts to disclose.
We gratefully acknowledge Dr. Deborah L. Gumucio as our advisor and for her invaluable support in defining the culture and imaging methods. We also thank Dr. Jim Brodie, Dr. Hong-Xiang Lu, Dr. Charlotte Mistretta, and Dr. Ann Grosse for their contributions to the development of the whole intestine organ culture system. Helpful discussions on imaging provided excellent advice from Dr. Chip Montrose, Michael Czerwinski and Sasha Meshinchi. All imaging was performed in the Microscopy and Image Analysis Laboratory at the University of Michigan. Funding support was provided by NIH R01 DK065850.
Name | Company | Catalog Number | Comments |
Fine dissecting forceps | Fine Science Tools | 11254-20 | 2 pairs |
70% Ethanol | |||
1x sterile Dulbecco's Phosphate-Buffered Saline (DPBS) | Gibco | 14040-133 | 500 ml |
6 well plates | Costar | 3516 | |
24 well plates | Costar | 3524 | |
60 x 15 mm petri dishes | Falcon | 451007 | |
Transwell plates, 24 mm inserts, 8.0 mm polycarbonate membranes | Corning Costar | 3428 | 6 inserts per plate |
BGJb media | Invitrogen | 12591-038 | 500 ml |
PenStrep (10,000U/ml Penicillin; 10,000 mg/ml Streptomycin) | Gibco | 15140 | |
Ascorbic Acid | Sigma | A0278 | make 5 mg/ml stock, filter, aliquot and store at -20 °C |
Mouth pipet (Drummond 1-15 inch aspirator tube assembly) | Fisher | 21-180-10 | remove the aspirator assembly and replace it with a 1,000 µl pipet tip which acts as an adaptor to plug in a 6 inch glass Pasteur pipet. |
6 inch glass pasteur pipets | |||
Capillary Tubes | World Precision Instruments | TW100F-4 | pull to needles |
4% Paraformaldehyde | made in 1 x PBS, pH to 7.3 | ||
Culture plates | Falcon | 353037 | |
Fine mesh stainless steel screen | purchase at hardware store | ||
Polycarbonate membranes | Thomas scientific | 4663H25 | alternatively, cut Corning Costar 3428 membranes off of transwell supports |
Instant glue | purchase at hardware store | gel based preferrably | |
35 x 10 mm plates | Falcon | 351008 | |
7% agarose | Sigma | A9414 | prepare w/v in 1x DPBS, heating to dissolve in a waterbath |
minutien pins | Fine Science Tools | 26002-20 | |
Phenol red free media (DMEM) | Gibco | 21063-029 | |
Xylazine (100 mg/ml) | AnaSed | 139-236 | |
Matrigel | BD | 356231 | basement membrane matrix, growth factor reduced, phenol red-free |
3-4% agarose | Sigma | A9414 | prepare w/v in 1x DPBS, heating to dissolve in a waterbath |
Imaging of fixed intestines | |||
Name of Material/Equipment | Company | Catalog Number | Comments/Description |
vaseline | purchase at pharmacy | used to make VALAP: equal parts vaseline, lanolin, paraffin | |
lanolin | Sigma | L7387 | used to make VALAP: equal parts vaseline, lanolin, paraffin |
paraffin | Surgipath | 39601006 | used to make VALAP: equal parts vaseline, lanolin, paraffin |
70% glycerol in 1 x PBS | |||
Focus clear and Mount Clear | CelExplorer Labs Co. | F101-KIT | |
Modeling clay | purchase at art supply store | ||
double stick tape | |||
cotton applicator swabs | |||
plastic molds, 10mm x 10mm x 5 mm) | Tissue Tek | 4565 | |
slides | |||
coverslips | |||
lab wipe | Kimberly Clark | 34155 | lint free delicate task wipe |
Theiler staging chart | http://www.emouseatlas.org/emap/ema/theiler_stages/ downloads/theiler2.pdf | ||
Leica SP5X confocal microscope | Leica | Used to conduct the live imaging | |
Leica DMI 6000 stand | Leica | Used to conduct the live imaging | |
Aqueous mounting medium (Prolong Gold) | Molecular Probes | P36930 | |
Name of Material/Equipment | Company | Catalog Number | Comments/Description |
24 well plate | Costar | 3524 | |
Triton X-100 | Sigma | T-8787 | used to make Permeabilization solution: 0.5% Triton X-100 in 1 x PBS |
Goat serum | used to make Blocking Solution: 4% Goat serum, 0.1% Tween20 in 1x PBS | ||
Tween20 | Sigma | P9416 |
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