Name: establishing organoids from human tooth as a powerful tool toward mechanistic research and regenerative therapy
Uploaded: 2022-04-13T13:45:00
Description: Watch this Scientific Journal Video about Establishing Organoids from Human Tooth as a Powerful Tool Toward Mechanistic Research and Regenerative Therapy at JoVE.com

We are grateful to all staff members of the Oral and Maxillofacial Surgery (MKA) of UZ Leuven, as well as the patients, for their invaluable help in collecting freshly extracted third molars. We would also like to thank Dr. Reinhilde Jacobs and Dr. Elisabeth Tijskens for their help with the sample collection. This work was supported by grants from KU Leuven (BOF) and FWO-Flanders (G061819N). L.H. is an FWO Ph.D. Fellow (1S84718N).

All methods described here have been approved by the Ethics Committee Research UZ/KU Leuven (13/0104U). Extracted third molars (wisdom teeth) were obtained after patients&#39; informed consent.
1. Preparations
<ol>
	<li>Prewarm a 48-well culture plate for 15-20 h in a 1.9% CO2 incubator at 37 &#176;C.</li>
	<li>Liquefy a Matrigel aliquot (growth factor-reduced; phenol red-free; further referred to as basement membrane matrix; BMM) on ice (4 &#176;C) for a minimum ...

<ol>
	<li>Yu, T., Klein, O. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+and+cellular+mechanisms+of+tooth+development,+homeostasis+and+repair.">Molecular and cellular mechanisms of tooth development, homeostasis and repair.</a> Development (Cambridge). 147 (2), (2020).</li><li>Arrow, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dental+enamel+defects,+caries+experience+and+oral+health-related+quality+of+life:+a+cohort+study.">Dental enamel defects, caries experience and oral health-related quality of life: a cohort study.</a> Australian Dental Journal. 62 (2), 165-172 (2017).</li><li>Mitsiadis, T. 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This protocol describes the efficient and reproducible generation of organoids starting from the human tooth. To our knowledge, this is the first methodology for establishing current-concept (epithelial) organoids starting from human dental tissue. The organoids are long-term expandable and display a tooth epithelial stemness phenotype, duplicating DESCs previously reported in the ERM compartment of the DF7. Moreover, the organoids replicate functional DESC/ERM characteristics, including the unfol...

Teeth have essential roles in food mastication, speech, and psychological well-being (self-image). The human tooth consists of highly mineralized tissues of varying density and hardness1. Dental enamel, the main component of the tooth crown, is the highest mineralized tissue in the human body. During enamel formation (amelogenesis), when teeth develop, dental epithelial stem cells (DESCs) differentiate into enamel-forming cells (ameloblasts). Once formed, the enamel is rarely repaired or renewed due to the apoptotic loss of the ameloblasts at the onset of tooth eruption1. Restoration of damaged enamel tissue, as caused by trauma or bacterial disease, is currently accomplished using synthetic materials; however, these are troubled with important shortcomings such as microleakage, inferior osseointegration and anchorage, finite life span, and lack of fully functional repair2. Hence, a robust and reliable culture of human DESCs with the capacity to generate ameloblasts and the potential to produce mineralized tissue would be a major step forward in the dental regenerative field.
Knowledge on human DESC phenotype and biological function are scarce3,4,5. Interestingly, DESCs of human teeth have been proposed to exist in the Epithelial Cell Rests of Malassez (ERM), cell clusters present within the dental follicle (DF), which surrounds unerupted teeth, and remains present in the periodontal ligament around the root once the tooth erupts1. ERM cells co-cultured with dental pulp have been found to differentiate into ameloblast-like cells and generate enamel-like tissue6. However, profound studies of the specific role of ERM cells in enamel (re-) generation have been limited due to the lack of reliable study models7. Current ERM in vitro culture systems are hampered by limited life span and quick loss of phenotype in the 2D conditions standardly used8,9,10,11,12. Hence, a tractable in vitro system to faithfully expand, study, and differentiate human DESCs is strongly needed.
During the last decade, a powerful technique to grow epithelial stem cells in vitro has been successfully applied to several types of (human) epithelial tissues to study their biology as well as disease13,14,15,16. This technology enables the tissue epithelial stem cells to self-develop into 3D cell constructions (i.e., organoids) when seeded into an extracellular matrix (ECM)-mimicking scaffold (typically, Matrigel) and cultured in a defined medium replicating the tissue&#39;s stem cell niche signaling and/or embryogenesis. Typical growth factors needed for organoid development include epidermal growth factor (EGF) and wingless-type MMTV integration site (WNT) activators14,15,16. The resultant organoids are characterized by lasting fidelity in mimicking the tissue&#39;s original epithelial stem cells, as well as high expandability while retaining their phenotype and functional properties, thereby overcoming the often-limited primary human tissue availability as acquired from the clinic. To establish organoids, isolation of the epithelial stem cells from the heterogeneous tissue (i.e., comprising other cell types such as mesenchymal cells) prior to culturing is not required as mesenchymal cells do not attach to, or thrive in, the ECM, eventually resulting in purely epithelial organoids13,16,17,18,19. This promising and versatile technology has led to the development of manifold organoid models from various human epithelial tissues. However, human tooth-derived organoids, valuable for deep study of tooth development, regeneration and disease, were not established yet20,21. We recently succeeded in developing such a new organoid model starting from DF tissue from third molars (wisdom teeth) extracted from adolescent patients19.
Here, we describe the protocol to develop epithelial organoid cultures from the adult human tooth (i.e., from the DF of third molars) (Figure 1A). The resultant organoids express ERM-associated stemness markers while being long-term expandable. Intriguingly, opposite to most other organoid models, the typically needed EGF is redundant for robust organoid development and growth. Interestingly, the stemness organoids show ameloblast differentiation properties, thereby mimicking ERM/DESC features and processes occurring in vivo. The new and unique organoid model described here allows exploring DESC biology, plasticity, and differentiation capacity and opens the door for taking the first steps toward tooth-regenerative approaches.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1.5 mL Microcentrifuge tube</td>
			<td>Eppendorf</td>
			<td>30120.086</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL Centrifuge tube</td>
			<td>Corning</td>
			<td>430052</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Mercaptoethanol</td>
			<td>Sigma-Aldrich</td>
			<td>M-6250</td>
			<td></td>
		</tr>
		<tr>
			<td>48-well flat bottom plates</td>
			<td>Corning</td>
			<td>3548</td>
			<td></td>
		</tr>
		<tr>
			<td>50 mL Centrifuge tube</td>
			<td>Corning</td>
			<td>430290</td>
			<td></td>
		</tr>
		<tr>
			<td>A83-01</td>
			<td>Sigma-Aldrich</td>
			<td>SML0788</td>
			<td></td>
		</tr>
		<tr>
			<td>Agarose</td>
			<td>Lonza</td>
			<td>50004</td>
			<td></td>
		</tr>
		<tr>
			<td>Albumin Bovine (cell culture grade)</td>
			<td>Serva</td>
			<td>47330.03</td>
			<td></td>
		</tr>
		<tr>
			<td>AMELX antibody</td>
			<td>Santa Cruz</td>
			<td>sc-365284</td>
			<td></td>
		</tr>
		<tr>
			<td>Amphotericin B</td>
			<td>Gibco</td>
			<td>15200018</td>
			<td></td>
		</tr>
		<tr>
			<td>B27 (without vitamin A)</td>
			<td>Gibco</td>
			<td>12587-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Cassette</td>
			<td>VWR</td>
			<td>7202191</td>
			<td></td>
		</tr>
		<tr>
			<td>Catalase from bovine liver</td>
			<td>Sigma-Aldrich</td>
			<td>C100</td>
			<td></td>
		</tr>
		<tr>
			<td>CD44 antibody</td>
			<td>Abcam</td>
			<td>ab34485</td>
			<td></td>
		</tr>
		<tr>
			<td>Cell strainer, 40 &#181;m</td>
			<td>Falcon</td>
			<td>352340</td>
			<td></td>
		</tr>
		<tr>
			<td>Cholera Toxin</td>
			<td>Sigma-Aldrich</td>
			<td>C8052</td>
			<td></td>
		</tr>
		<tr>
			<td>Citric acid</td>
			<td>Sigma-Aldrich</td>
			<td>C0759</td>
			<td></td>
		</tr>
		<tr>
			<td>CK14 antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>MA5-11599</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase IV</td>
			<td>Gibco</td>
			<td>17104-019</td>
			<td></td>
		</tr>
		<tr>
			<td>Cover glass</td>
			<td>VWR</td>
			<td>6310146</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryobox</td>
			<td>Thermo Scientific</td>
			<td>5100-0001</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryovial</td>
			<td>Thermo Fisher Scientific</td>
			<td>375353</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethylsulfoxide (DMSO)</td>
			<td>Sigma-Aldrich</td>
			<td>D2650</td>
			<td></td>
		</tr>
		<tr>
			<td>Dispase II</td>
			<td>Sigma-Aldrich</td>
			<td>D4693</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM 1:1 F12 without Fe</td>
			<td>Invitrogen</td>
			<td>074-90715A</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM powder high glucose</td>
			<td>Gibco</td>
			<td>52100039</td>
			<td></td>
		</tr>
		<tr>
			<td>Dnase</td>
			<td>Sigma-Aldrich</td>
			<td>D5025-15KU</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey serum</td>
			<td>Sigma-Aldrich</td>
			<td>D9663 - 10ML</td>
			<td></td>
		</tr>
		<tr>
			<td>Embedding workstation, 220 to 240 Vac</td>
			<td>Thermo Fisher Scientific</td>
			<td>12587976</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol absolute, &#8805;99.8% (EtOH)</td>
			<td>Fisher Chemical</td>
			<td>E/0650DF/15</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal bovine serum (FBS)</td>
			<td>Sigma-Aldrich</td>
			<td>F7524</td>
			<td></td>
		</tr>
		<tr>
			<td>FGF10</td>
			<td>Peprotech</td>
			<td>100-26</td>
			<td></td>
		</tr>
		<tr>
			<td>FGF2 (= basic FGF)</td>
			<td>R&#38;D Systems</td>
			<td>234-FSE-025</td>
			<td></td>
		</tr>
		<tr>
			<td>FGF8</td>
			<td>Peprotech</td>
			<td>AF-100-25</td>
			<td></td>
		</tr>
		<tr>
			<td>GenElute Mammaliam Total RNA Miniprep Kit</td>
			<td>Sigma-Aldrich</td>
			<td>RTN350-1KT</td>
			<td>Includes 1% &#946;-mercaptoethanol dissolved in lysis buffer</td>
		</tr>
		<tr>
			<td>Glass Pasteur pipette</td>
			<td>Niko Mechanisms</td>
			<td>170-40050</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycine</td>
			<td>VWR</td>
			<td>101194M</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma-Aldrich</td>
			<td>H4034</td>
			<td></td>
		</tr>
		<tr>
			<td>IGF-1</td>
			<td>PeproTech</td>
			<td>100-11</td>
			<td></td>
		</tr>
		<tr>
			<td>InSolution Y-27632 (ROCK inhibitor, RI)</td>
			<td>Sigma-Aldrich</td>
			<td>688001</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin from bovine pancreas</td>
			<td>Sigma-Aldrich</td>
			<td>I6634</td>
			<td></td>
		</tr>
		<tr>
			<td>ITGA6 antibody</td>
			<td>Sigma-Aldrich</td>
			<td>HPA012696</td>
			<td></td>
		</tr>
		<tr>
			<td>L-Glutamine</td>
			<td>Gibco</td>
			<td>25030024</td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel (growth factor-reduced; phenol red-free)</td>
			<td>Corning</td>
			<td>15505739</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope slide</td>
			<td>Thermo Fisher Scientific</td>
			<td>J1800AMNZ</td>
			<td></td>
		</tr>
		<tr>
			<td>Millex-GV Syringe Filter Unit, 0.22&#160;&#956;m</td>
			<td>Millipore</td>
			<td>SLGV033R</td>
			<td></td>
		</tr>
		<tr>
			<td>Minimum essential medium eagle (&#945;MEM)</td>
			<td>Sigma-Aldrich</td>
			<td>M4526</td>
			<td></td>
		</tr>
		<tr>
			<td>mouse IgG (Alexa 555) secondary antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>A-31570</td>
			<td></td>
		</tr>
		<tr>
			<td>N2</td>
			<td>Gibco</td>
			<td>17502-048</td>
			<td></td>
		</tr>
		<tr>
			<td>N-acetyl L-cysteine</td>
			<td>Sigma-Aldrich</td>
			<td>A7250</td>
			<td></td>
		</tr>
		<tr>
			<td>Nicotinamide</td>
			<td>Sigma-Aldrich</td>
			<td>N0636</td>
			<td></td>
		</tr>
		<tr>
			<td>Noggin</td>
			<td>PeproTech</td>
			<td>120-10C</td>
			<td></td>
		</tr>
		<tr>
			<td>P63 antibody</td>
			<td>Abcam</td>
			<td>ab124762</td>
			<td></td>
		</tr>
		<tr>
			<td>Pap Pen</td>
			<td>Sigma-Aldrich</td>
			<td>Z377821-1EA</td>
			<td>Marking pen</td>
		</tr>
		<tr>
			<td>Paraformaldehyde (PFA), 16%</td>
			<td>Merck</td>
			<td>8.18715</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin G sodium salt</td>
			<td>Sigma-Aldrich</td>
			<td>P3032</td>
			<td></td>
		</tr>
		<tr>
			<td>Penicillin-streptomycin (Pen/Strep)</td>
			<td>Gibco</td>
			<td>15140-122</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish</td>
			<td>Corning</td>
			<td>353002</td>
			<td></td>
		</tr>
		<tr>
			<td>Phosphate buffered saline (PBS)</td>
			<td>Gibco</td>
			<td>10010-015</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette (P20, P200, P1000)</td>
			<td>Eppendorf or others</td>
			<td>2231300006</td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic transfer pipette (3.5&#160;mL)</td>
			<td>Sarstedt</td>
			<td>86.1171.001</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit IgG (Alexa 488) secondary antibody</td>
			<td>Thermo Fisher Scientific</td>
			<td>A21206</td>
			<td></td>
		</tr>
		<tr>
			<td>RSPO1</td>
			<td>PeproTech</td>
			<td>120-38</td>
			<td></td>
		</tr>
		<tr>
			<td>SB202190 (p38i)</td>
			<td>Biotechne (Tocris)</td>
			<td>1264</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel (surgical blade)</td>
			<td>Swann-Morton</td>
			<td>207</td>
			<td></td>
		</tr>
		<tr>
			<td>SHH</td>
			<td>R&#38;D Systems</td>
			<td>464-SH-200</td>
			<td></td>
		</tr>
		<tr>
			<td>Silicone molds (Heating block)</td>
			<td>VWR</td>
			<td>720-1918</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride (NaCl)</td>
			<td>BDH</td>
			<td>102415K</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Hydrogen Carbonate (NaHCO3)</td>
			<td>Merck</td>
			<td>106329</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium-pyruvate (C3H3NaO3)</td>
			<td>Sigma-Aldrich</td>
			<td>P-5280</td>
			<td></td>
		</tr>
		<tr>
			<td>SOX2 antibody</td>
			<td>Abcam</td>
			<td>ab92494</td>
			<td></td>
		</tr>
		<tr>
			<td>StepOnePlus</td>
			<td>Thermo Fisher Scientific</td>
			<td></td>
			<td>Real-Time PCR System</td>
		</tr>
		<tr>
			<td>Stericup-GP, 0.22 &#181;m</td>
			<td>Millipore</td>
			<td>SCGPU02RE</td>
			<td></td>
		</tr>
		<tr>
			<td>Steriflip-GP Sterile Centrifuge Tube Top Filter Unit, 0.22 &#956;m</td>
			<td>Millipore</td>
			<td>SCGP00525</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile 1000 &#956;L pipette tips with filter</td>
			<td>Greiner</td>
			<td>740288</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile 20 &#956;L pipette tips with filter</td>
			<td>Greiner</td>
			<td>774288</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile 200 &#956;L pipette tips with and without filter</td>
			<td>Greiner</td>
			<td>739288</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile H2O</td>
			<td>Fresenius</td>
			<td>B230531</td>
			<td></td>
		</tr>
		<tr>
			<td>Streptomycin sulfate salt</td>
			<td>Sigma-Aldrich</td>
			<td>S6501</td>
			<td></td>
		</tr>
		<tr>
			<td>Superscript III first-strand synthesis supermix</td>
			<td>Invitrogen</td>
			<td>11752-050</td>
			<td>Reverse transcription kit</td>
		</tr>
		<tr>
			<td>Tissue processor</td>
			<td>Thermo Scientific</td>
			<td>12505356</td>
			<td></td>
		</tr>
		<tr>
			<td>Transferrin</td>
			<td>Serva</td>
			<td>36760.01</td>
			<td></td>
		</tr>
		<tr>
			<td>Triton X-100</td>
			<td>Sigma</td>
			<td>T8787-50ML</td>
			<td></td>
		</tr>
		<tr>
			<td>TrypLE express</td>
			<td>Gibco</td>
			<td>12605-010</td>
			<td></td>
		</tr>
		<tr>
			<td>Vectashield mounting medium+DAPI</td>
			<td>Labconsult NV</td>
			<td>H-1200</td>
			<td>Antifade mounting medium with DAPI</td>
		</tr>
		<tr>
			<td>WNT3a</td>
			<td>Biotechne (Tocris)</td>
			<td>5036-WN-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Xylenes, 99%, for biochemistry and histology</td>
			<td>VWR</td>
			<td>2,89,75,325</td>
			<td></td>
		</tr>
	</tbody>
</table>

establishing organoids from human tooth as a powerful tool toward mechanistic research and regenerative therapy

Teeth are of key importance in life not only for food mastication and speech but also for psychological well-being. Knowledge on human tooth development and biology is scarce. In particular, not much is known about the tooth's epithelial stem cells and their function. We succeeded in developing a novel organoid model starting from human tooth tissue (i.e., dental follicle, isolated from extracted wisdom teeth). The organoids are robustly and long-term expandable and recapitulate the proposed human tooth epithelial stem cell compartment in terms of marker expression as well as functional activity. In particular, the organoids are capable to unfold an ameloblast differentiation process as occurring in vivo during amelogenesis. This unique organoid model will provide a powerful tool to study not only human tooth development but also dental pathology, and may pave the way toward tooth-regenerative therapy. Replacing lost teeth with a biological tooth based on this new organoid model could be an appealing alternative to the current standard implantation of synthetic materials.

Tooth organoid development 
We provide a detailed protocol to establish organoid cultures from human DF tissue acquired following wisdom tooth extraction (Figure 1A). Isolated DF is enzymatically and mechanically dissociated. The obtained cells are cultured within BMM in media that were empirically defined for optimal organoid development and growth (tooth organoid medium; TOM)19.
The organoids typically develop within...

Watch this Scientific Journal Video about Establishing Organoids from Human Tooth as a Powerful Tool Toward Mechanistic Research and Regenerative Therapy at JoVE.com

Establishing Organoids from Human Tooth as a Powerful Tool Toward Mechanistic Research and Regenerative Therapy

We present a protocol to develop epithelial organoid cultures starting from human tooth. The organoids are robustly expandable and recapitulate the tooth's epithelial stem cells, including their ameloblast differentiation capacity. The unique organoid model provides a promising tool to study human dental (stem cell) biology with perspectives for tooth-regenerative approaches.

Teeth are of key importance in life not only for food mastication and speech but also for psychological well-being. Knowledge on human tooth development ...

This new human tooth-derived organoid model provides the first powerful tool to decipher human dental stem cell biology with perspectives toward tooth regenerative applications. At present, this tooth organoid model is the only available tool to reliably and robustly grow and expand human tooth epithelial stem cells. This organoid protocol can be applied to establish research models, not only from healthy, but also diseased tooth such as dental tumors and bacterial impact.Exploration of such disease models may uncover new therapeutic targets. This organoid model is highly instrumental in deciphering the enamel formation process in the human tooth, and may enable the construction of tooth parts such as enamel for a generative purposes. Demonstrating the procedure will be Lara Hemeryck, PhD student in my research group.To begin, collect the third molars with associated dental follicles in the collection medium placed on ice and transfer the content of the tubes to a Petri dish. Hold the tooth with a tweezer and carefully isolate the dental follicles using a surgical blade. Wash the remaining blood off the dental follicles by briefly placing the dental follicle tissues in the first well of 70%ethanol for 20 seconds, then transfer it to the next death ethanol plate for 20 seconds and further to the third ethanol well.Continue rinsing it in phosphate-buffered saline wells three times followed by rinsing the dental follicles in the three remaining dental follicles collection medium wells for a maximum of 20 minutes in total. Transfer the rinsed dental follicles to a new Petri dish. Cut a small piece of one of the dental follicles for a paraformaldehyde fixation and store it in a microcentrifuge tube containing 500 microliters of collection medium for a maximum six hours.Mince the rest of the dental follicles into small pieces and transfer them to a 15-milliliters tube containing four milliliters of prewarmed dissociation medium, then incubate the tube at 37 degrees Celsius for two hours in water bath. Every 15 minutes, pipette the dental follicles dissociation medium and mix up and down using a glass pipette to speed the tissue disintegration. When pieces of dental follicles are no longer observed, proceed with the dissociation using a narrowed, fire-polished Pasteur pipette.In the meantime, prepare 10 milliliters of medium A containing 100 microliters of DNase and add five milliliters of this medium to each tube with dissociated dental follicles. Incubate for one minute at room temperature. Rinse the filter with one milliliter of medium A.Combine the several tubes of dissociated dental follicles from one patient at this step and centrifuge the filtered cell suspension at 200 times g for 10 minutes at 4 degrees Celsius.Remove the supernatant. Resuspend the pellet in one milliliter of serum-free defined medium and transfer the cell suspension to a 1.5 milliliter microcentrifuge tube. Calculate the cell concentration using an automated cell counter and calculate the number of wells that can be seeded.The final mix is composed of cell suspension and basement membrane matrix at a ratio of 30 to 70. Remove the appropriate amount of supernatant and resuspend it slowly to obtain a 70-to-30 ratio of ice-cold basement membrane matrix to cell suspension for plating. Once resuspended in the basement membrane matrix, keep the microcentrifuge tube on ice to avoid basement membrane matrix solidification.Pipette the 20 microliters of basement membrane matrix droplets in the center of the preheated 48-well culture plate. Flip the plate upside down and place it to solidify in a 1.9%carbon dioxide incubator at 37 degrees Celsius for 20 minutes. Add rho-associated kinase inhibitor and amphotericin B to tooth organoid medium and prewarm the medium in a 37-degrees Celsius water bath.Take the 48-well plate from the incubator. Place it upright and add 250 microliters of the prepared prewarmed medium to each well with a basement membrane matrix droplet containing the cells and return the plate to the carbon dioxide incubator. To refresh the medium, tilt the plate at a 45-degrees angle.Gently remove the previous medium, while avoiding touching the basement membrane matrix droplet and add 250 microliters of new prewarmed tooth organoid medium every two to three days. To carry out the passage of the organoids, remove the medium from the wells with organoids and pool up to four confluent wells. To collect the organoids, add 400 microliters of ice-cold serum-free defined medium per well directly onto the membrane matrix droplet and repeatedly pipette the medium up and down until the entire droplet is dislodged.If wells are pooled, transfer the 400 microliters from the first well to the next to dislodge the organoid containing droplets. Transfer the dislodged organoid assembly to a 1.5 microliter microcentrifuge tube and repeat the addition of serum-free defined medium until all the organoid structures are collected from the wells. Centrifuge it at 200 times g for five minutes at 4 degrees Celsius.Remove the supernatant from the centrifuge tube and resuspend the pellet in a prewarmed aliquot of TrypLE Express. Add 400 microliters of ice-cold serum-free defined medium to inactivate the enzyme and centrifuge it at 200 times g for five minutes at 4 degrees Celsius. Remove the supernatant.Pre-coat a tip with ice-cold serum-free defined medium and re-suspend the organoid pellet in sterile condition. Re-suspend the pellet in 200 microliters of ice-cold serum free defined medium for the low passage method. Push the completely emptied pipette tip against the bottom of the micro centrifuge tube to reduce its diameter.Pipette up and down for five minutes to mechanically disrupt the organoids. For the higher passage method, resuspend the pellet in 700 microliters of ice-cold serum-free defined medium with a P1000 tip. Add a P200 tip to this P1000 tip and pre-coat with ice-cold serum-free defined medium.Prevent air bubble formation by adjusting the pipette's volume setting. Aspire at least 90%of the medium volume with organoids and pipette up and down for five minutes to mechanically disrupt the organoids. The organoids typically develop two weeks after dental follicle cell seeding.The organoids are long-term expandable up to 11 passages. Seeding around 20, 000 cells per basement membrane matrix droplet yields an optimal density of organoids, whereas seeding higher cell numbers leads to suboptimal organoid outgrowth with similar organoids at too high density due to insufficient space to grow. The developed organoids show a dense appearance and contain cells displaying a high nucleocytoplasmic ratio.Moreover, the organoids express the ERM marker cytokeratin 14 confirming their epithelial origin and other proposed ERM markers, such as P63, CD44, and integrin alpha-6. Organoids express SOX2, a well-known DESC marker in mice. Interestingly, the main component of the enamel matrix, amelogenin, also expressed in the organoids.The organoids retain their ERMM stemness phenotype during passaging as shown by the stable expression of markers. For optimal long-term organoids growth, it is essential to use the recommended passage methods meaning or the low passage or the higher passage methods. Once formed, the organoids can be used to scrutinize the amelogenesis process further and enamel matrix deposition currently not achieved in dentistry research.This technique enables the exploration of dental epithelial stem cell biology, the process of enamel formation, and the interaction with the tooth mesenchyme, an interplay essential for correct tooth formation.

establishing-organoids-from-human-tooth-as-powerful-tool-toward

Research

JoVE Journal

Developmental Biology

Adenoviral Gene Therapy for Diabetic Keratopathy: Effects on Wound Healing and Stem Cell Marker Expression in Human Organ-cultured Corneas and Limbal Epithelial Cells

The goal of this protocol is to describe molecular alterations in human diabetic corneas and demonstrate how they can be alleviated by adenoviral gene therapy in organ-cultured corneas. The diabetic corneal disease is a complication of diabetes with frequent abnormalities of corneal nerves and epithelial wound healing. We have also documented significantly altered expression of several putative epithelial stem cell markers in human diabetic corneas. To alleviate these changes, adenoviral gene therapy was successfully implemented using the upregulation of c-met proto-oncogene expression and/or the downregulation of proteinases matrix metalloproteinase-10 (MMP-10) and cathepsin F. This therapy accelerated wound healing in diabetic corneas even when only the limbal stem cell compartment was transduced. The best results were obtained with combined treatment. For possible patient transplantation of normalized stem cells, an example is also presented of the optimization of gene transduction in stem cell-enriched cultures using polycationic enhancers. This approach may be useful not only for the selected genes but also for the other mediators of corneal epithelial wound healing and stem cell function.

An example of adenoviral gene therapy in the human diabetic organ-cultured corneas is presented towards the normalization of delayed wound healing and markedly reduced epithelial stem cell marker expression in these corneas. It also describes the optimization of this process in stem cell-enriched limbal epithelial cultures.

The goal of this protocol is to describe molecular alterations in human diabetic corneas and demonstrate how they can be alleviated by adenoviral gene ...

Generation of Integration-free Induced Pluripotent Stem Cells from Human Peripheral Blood Mononuclear Cells Using Episomal Vectors

Induced Pluripotent Stem Cells (iPSCs) hold great promise for disease modeling and regenerative therapies. We previously reported the use of Episomal Vectors (EV) to generate integration-free iPSCs from peripheral blood mononuclear cells (PB MNCs). The episomal vectors used are DNA plasmids incorporated with oriP and EBNA1 elements from the Epstein-Barr (EB) virus, which&#160;allow for replication and long-term retainment of plasmids in mammalian cells, respectively. With further optimization, thousands of iPSC colonies can be obtained from 1 mL of peripheral blood. Two critical factors for achieving high reprogramming efficiencies&#160;are: 1) the use of a 2A &#34;self-cleavage&#34; peptide to link OCT4 and SOX2, thus achieving equimolar expression of the two factors; 2) the use of two vectors to express MYC and KLF4 individually. Here we describe a step-by-step protocol for generating integration-free iPSCs from adult peripheral blood samples. The generated iPSCs are integration-free as residual episomal plasmids are undetectable after five passages. Although the reprogramming efficiency is comparable to that of Sendai Virus (SV) vectors, EV plasmids are considerably more economical than the commercially available SV vectors. This affordable EV reprogramming system holds potential for clinical applications in regenerative medicine and provides an approach for the direct reprogramming of PB MNCs to integration-free mesenchymal stem cells, neural stem cells, etc.

This protocol describes a detailed method for efficient generation of integration-free iPSCs from human adult peripheral blood cells. With the use of four oriP/EBNA-based episomal vectors to express the reprogramming factors, KLF4, MYC, BCL-XL, or OCT4 and SOX2, thousands of iPSC colonies can be obtained from 1 mL of peripheral blood.

Induced Pluripotent Stem Cells (iPSCs) hold great promise for disease modeling and regenerative therapies. We previously reported the use of Episomal ...

Processing of Human Cardiac Tissue Toward Extracellular Matrix Self-assembling Hydrogel for In Vitro and In Vivo Applications

Acellular extracellular matrix preparations are useful for studying cell-matrix interactions and facilitate regenerative cell therapy applications. Several commercial extracellular matrix products are available as hydrogels or membranes, but these do not possess tissue-specific biological activity. Because perfusion decellularization is usually not possible with human heart tissue, we developed a 3-step immersion decellularization process. Human myocardial slices procured during surgery are first treated with detergent-free hyperosmolar lysis buffer, followed by incubation with the ionic detergent, sodium dodecyl sulfate, and the process is completed by exploiting the intrinsic DNase activity of fetal bovine serum. This technique results in cell-free sheets of cardiac extracellular matrix with largely preserved fibrous tissue architecture and biopolymer composition, which were shown to provide specific environmental cues to cardiac cell populations and pluripotent stem cells. Cardiac extracellular matrix sheets can then be further processed into a microparticle powder without further chemical modification, or, via short-term pepsin digestion, into a self-assembling cardiac extracellular matrix hydrogel with preserved bioactivity.

Processing of Human Cardiac Tissue Toward Extracellular Matrix Self-assembling Hydrogel for In Vitro and In Vivo Applications

This protocol describes the complete decellularization of human myocardium while preserving its extracellular matrix components. Further processing of the extracellular matrix results in the production of microparticles and a cytoprotective self-assembling hydrogel.

Acellular extracellular matrix preparations are useful for studying cell-matrix interactions and facilitate regenerative cell therapy applications. ...

Generation of Standardized and Reproducible Forebrain-type Cerebral Organoids from Human Induced Pluripotent Stem Cells

The human cortex is highly expanded and exhibits a complex structure with specific functional areas, providing higher brain function, such as cognition. Efforts to study human cerebral cortex development have been limited by the availability of model systems. Translating results from rodent studies to the human system is restricted by species differences and studies on human primary tissues are hampered by a lack of tissue availability as well as ethical concerns. Recent development in human pluripotent stem cell (PSC) technology include the generation of three-dimensional (3D) self-organizing organotypic culture systems, which mimic to a certain extent human-specific brain development in vitro. Currently, various protocols are available for the generation of either whole brain or brain-region specific organoids. The method for the generation of homogeneous and reproducible forebrain-type organoids from induced PSC (iPSC), which we previously established and describe here, combines the intrinsic ability of PSC to self-organize with guided differentiation towards the anterior neuroectodermal lineage and matrix embedding to support the formation of a continuous neuroepithelium. More specifically, this protocol involves: (1) the generation of iPSC aggregates, including the conversion of iPSC colonies to a confluent monolayer culture; (2) the induction of anterior neuroectoderm; (3) the embedding of neuroectodermal aggregates in a matrix scaffold; (4) the generation of forebrain-type organoids from neuroectodermal aggregates; and (5) the fixation and validation of forebrain-type organoids. As such, this protocol provides an easily applicable system for the generation of standardized and reproducible iPSC-derived cortical tissue structures in vitro.

Cerebral organoids represent a new model system to investigate early human brain development in vitro. This article provides the detailed methodology to efficiently generate homogeneous dorsal forebrain-type organoids from human induced pluripotent stem cells including critical characterization and validation steps.

The human cortex is highly expanded and exhibits a complex structure with specific functional areas, providing higher brain function, such as cognition. ...

Generation of Scaffold-free, Three-dimensional Insulin Expressing Pancreatoids from Mouse Pancreatic Progenitors In Vitro

The pancreas is a complex organ composed of many different cell types that work together to regulate blood glucose homeostasis and digestion. These cell types include enzyme-secreting acinar cells, an arborized ductal system responsible for the transportation of enzymes to the gut, and hormone-producing endocrine cells. 
Endocrine beta-cells are the sole cell type in the body that produce insulin to lower blood glucose levels. Diabetes, a disease characterized by a loss or the dysfunction of beta-cells, is reaching epidemic proportions. Thus, it is essential to establish protocols to investigate beta-cell development that can be used for screening purposes to derive the drug and cell-based therapeutics. While the experimental investigation of mouse development is essential, in vivo studies are laborious and time-consuming. Cultured cells provide a more convenient platform for screening; however, they are unable to maintain the cellular diversity, architectural organization, and cellular interactions found in vivo. Thus, it is essential to develop new tools to investigate pancreatic organogenesis and physiology.
Pancreatic epithelial cells develop in the close association with mesenchyme from the onset of organogenesis as cells organize and differentiate into the complex, physiologically competent adult organ. The pancreatic mesenchyme provides important signals for the endocrine development, many of which are not well understood yet, thus difficult to recapitulate during the in vitro culture. Here, we describe a protocol to culture three-dimensional, cellular complex mouse organoids that retain mesenchyme, termed pancreatoids. The e10.5 murine pancreatic bud is dissected, dissociated, and cultured in a scaffold-free environment. These floating cells self-assemble with mesenchyme enveloping the developing pancreatoid and a robust number of endocrine beta-cells developing along with the acinar and the duct cells. This system can be used to study the cell fate determination, structural organization, and morphogenesis, cell-cell interactions during organogenesis, or for the drug, small molecule, or genetic screening.

Generation of Scaffold-free, Three-dimensional Insulin Expressing Pancreatoids from Mouse Pancreatic Progenitors In Vitro

Here, we present a protocol to generate insulin expressing 3D murine pancreatoids from free-floating e10.5 dissociated pancreatic progenitors and the associated mesenchyme.

The pancreas is a complex organ composed of many different cell types that work together to regulate blood glucose homeostasis and digestion. These cell ...

Generation of Induced Neural Stem Cells from Peripheral Mononuclear Cells and Differentiation Toward Dopaminergic Neuron Precursors for Transplantation Studies

Parkinson&#39;s disease (PD) is caused by degeneration of dopaminergic (DA) neurons at the substantia nigra pars compacta (SNpc) in the ventral mesencephalon (VM). Cell replacement therapy holds great promise for treatment of PD. Recently, induced neural stem cells (iNSCs) have emerged as a potential candidate for cell replacement therapy due to the reduced risk of tumor formation and the plasticity to give rise to region-specific neurons and glia. iNSCs can be reprogrammed from autologous somatic cellular sources, such as fibroblasts, peripheral blood mononuclear cells (PBMNCs) and various other types of cells. Compared with other types of somatic cells, PBMNCs are an appealing starter cell type because of the ease to access and expand in culture. Sendai virus (SeV), an RNA non-integrative virus, encoding reprogramming factors including human OCT3/4, SOX2, KLF4 and c-MYC, has a negative-sense, single-stranded, non-segmented genome that does not integrate into host genome, but only replicates in the cytoplasm of infected cells, offering an efficient and safe vehicle for reprogramming. In this study, we describe a protocol in which iNSCs are obtained by reprogramming PBMNCs, and differentiated into specialized VM DA neurons by a two-stage method. Then DA precursors are transplanted into unilaterally 6-hyroxydopamine (6-OHDA)-lesioned PD mouse models to evaluate the safety and efficacy for treatment of PD. This method provides a platform to investigate the functions and therapeutic effects of patient-specific DA neural cells in vitro and in vivo.

The protocol presents the reprogramming of peripheral blood mononuclear cells to induce neural stem cells by Sendai virus infection, differentiation of iNSCs into dopaminergic neurons, transplantation of DA precursors into the unilaterally-lesioned Parkinson&#39;s disease mouse models, and evaluation of the safety and efficacy of iNSC-derived DA precursors for PD treatment.

Parkinson&#39;s disease (PD) is caused by degeneration of dopaminergic (DA) neurons at the substantia nigra pars compacta (SNpc) in the ventral ...

Formation of Human Periodontal Ligament Cell Spheroids on Chitosan Films

Periodontal ligament (PDL) cells hold great promise for periodontal tissue regeneration. Conventionally, PDL cells are cultured on two-dimensional (2D) substrates such as tissue culture polystyrene (TCPS). However, characteristic changes of PDL cells have been observed during in vitro culture. This phenomenon is probably because the 2D TCPS differs from the in vivo three-dimensional (3D) microenvironment. Compared to cells cultured on 2D substrates, cells grown in a 3D microenvironment exhibit more similarities to in vivo cells. Therefore, 3D cell culture models provide a promising alternative for conventional 2D monolayer cell culture. To improve conventional PDL cell culture models, we have recently developed a 3D cell culture method, which is based on spheroid formation of PDL cells on chitosan films. Here, we present detailed cell spheroid culture protocols based on chitosan films. The 3D culture system of PDL cellular spheroids overcome some of the limitations related to conventional 2D monolayer cell culture, and thus may be suitable for producing PDL cells with an enhanced therapeutic efficacy for future periodontal tissue regeneration.

Here, we present protocols of culturing human periodontal ligament (PDL) cell spheroids by chitosan films. The culture of three-dimensional (3D) cellular spheroids provides an alternative to conventional tissue culture polystyrene (TCPS) culture system.

Periodontal ligament (PDL) cells hold great promise for periodontal tissue regeneration. Conventionally, PDL cells are cultured on two-dimensional (2D) ...

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C (UV-C) Damage

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational health hazard. Here, we demonstrate the exposure of primary stem cells from the mouse ocular surface to UV-C radiation. Reactive oxygen species (ROS) formation is the readout of the extent of oxidative stress/damage. In an experimental in vitro setting, it is also essential to assess the percentage of dead cells generated due to oxidative stress. In this article, we will demonstrate the 2&#39;,7&#39;-Dichlorofluoresceindiacetate (DCFDA) staining of UV-C exposed mouse primary ocular surface stem cells and their quantification based on the fluorescent images of DCFDA staining. DCFDA staining directly corresponds to ROS generation. We also demonstrate the quantification of dead and live cells by simultaneous staining with propidium iodide (PI) and Hoechst 3332 respectively and the percentage of DCFDA (ROS positive) and PI positive cells.

Assessment of Oxidative Damage in the Primary Mouse Ocular Surface Cells/Stem Cells in Response to Ultraviolet-C UV-C Damage

This protocol demonstrates the simultaneous detection of reactive oxygen species (ROS), live cells, and dead cells in live primary cultures from mouse ocular surface cells. 2&#39;,7&#39;-Dichlorofluoresceindiacetate, propidium iodide, and Hoechst staining are used to assess the ROS, dead cells, and live cells, respectively, followed by imaging and analysis.

The ocular surface is subjected to regular wear and tear due to various environmental factors. Exposure to UV-C radiation constitutes an occupational ...

A Static Self-Directed Method for Generating Brain Organoids from Human Embryonic Stem Cells

Human brain organoids differentiated from embryonic stem cells offer the unique opportunity to study complicated interactions of multiple cell types in a three-dimensional system. Here we present a relatively straightforward and inexpensive method that yields brain organoids. In this protocol human pluripotent stem cells are broken into small clusters instead of single cells and grown in basic media without a heterologous basement membrane matrix or exogenous growth factors, allowing the intrinsic developmental cues to shape the organoid&#39;s growth. This simple system produces a diversity of brain cell types including glial and microglial cells, stem cells, and neurons of the forebrain, midbrain, and hindbrain. Organoids generated from this protocol also display hallmarks of appropriate temporal and spatial organization demonstrated by brightfield images, histology, immunofluorescence and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). Because these organoids contain cell types from various parts of the brain, they can be utilized for studying a multitude of diseases. For example, in a recent paper we demonstrated the use of organoids generated from this protocol for studying the effects of hypoxia on the human brain. This approach can be used to investigate an array of otherwise difficult to study conditions such as neurodevelopmental handicaps, genetic disorders, and neurologic diseases.

This protocol was generated as a means to produce brain organoids in a simplified, low cost manner without exogenous growth factors or basement membrane matrix while still maintaining the diversity of brain cell types and many features of cellular organization.

Human brain organoids differentiated from embryonic stem cells offer the unique opportunity to study complicated interactions of multiple cell types in a ...

Preparation of Small RNA Libraries for Sequencing from Early Mouse Embryos

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs during early development are technically challenging due to the limiting cell number. Moreover, many approaches require a miRNA of interest to be defined in assays such as northern blotting, microarray, and qPCR. Therefore, the expression of many miRNAs and their isoforms have not been studied during early development. Here, we demonstrate a protocol for small RNA sequencing of sorted cells from early mouse embryos to enable relatively unbiased profiling of miRNAs in early populations of neural crest cells. We overcome the challenges of low cell input and size selection during library preparation using amplification and gel-based purification. We identify embryonic age as a variable accounting for variation between replicates and stage-matched mouse embryos must be used to accurately profile miRNAs in biological replicates. Our results suggest that this method can be broadly applied to profile the expression of miRNAs from other lineages of cells. In summary, this protocol can be used to study how miRNAs regulate developmental programs in different cell lineages of the early mouse embryo.

We describe a technique for profiling microRNAs in early mouse embryos. This protocol overcomes the challenge of low cell input and small RNA enrichment. This assay can be used to analyze changes in miRNA expression over time in different cell lineages of the early mouse embryo.

MicroRNAs (miRNAs) are important for the complex regulation of cell fate decisions and developmental timing. In vivo studies of the contribution of miRNAs ...