This research was supported by the California Institute for Regenerative Medicine (CIRM)&#160;&#160;(DISC2-COVID19-12022).

This study protocol was approved by the Institutional Review Board of UCSD&#39;s Human Research Protections Program (181180).
1. Definitive endoderm induction from induced pluripotent stem cells (Day 1 - 3)
<ol>
	<li>Slowly thaw growth factor reduced (GFR)-basement membrane (BM) matrix medium on ice 30 minutes prior to use. In cold DMEM/F12, mixture, dilute the GFR BM matrix medium 1:1 such that it constitutes 50% of this medium. Place P1000 pipette tips in the freezer to chill prior to use....

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The authors have nothing to disclose.

The successful differentiation of 3D whole lung organoids (WLO) relies on a multi-step, 6-week protocol with attention to detail, including time of exposure to growth factors and small molecules, cellular density after passaging, and the quality of hiPSCs. For troubleshooting, see Table 2. hiPSCs should be approximately 70%-80% confluent, with less than 5% spontaneous differentiation prior to dissociation. This protocol calls for &#34;mTeSR plus&#34; medium; however,&#160; plain &#34;mTeSR&#34; medium&#1...

The lung is a complicated, heterogeneous, dynamic organ that develops in six distinct stages - embryonic, pseudoglandular, canalicular, saccular, alveolar, and microvascular maturation1,2. The latter two phases occur pre and postnatally in human development while the first four stages occur exclusively during fetal development unless preterm birth occurs3. The embryonic phase begins in the endodermal germ layer and concludes with the budding of the trachea and lung buds. Lung development occurs in part via signaling between the epithelial and mesenchymal cells4. These interactions result in lung branching, proliferation, cellular fate determination and cellular differentiation of the developing lung. The lung is divided into conducting zones (trachea to the terminal bronchioles) and respiratory zones (respiratory bronchioles to the alveoli). Each zone contains unique epithelial cell types; including basal, secretory, ciliated, brush, neuroendocrine, and ionocyte cells in the conducting airway5, followed by alveolar type I and II cells in the respiratory epithelium6. Much is still unknown about the development and response to injury of the various cell types. iPSC derived lung organoid models enable the study of mechanisms that drive human lung development, the effects of genetic mutations on pulmonary function, and the response of both the epithelium and mesenchyme to infectious agents without the need for primary human lung tissue.
Markers corresponding to the various stages of embryonic differentiation include CXCR4, cKit, FOXA2, and SOX17 for definitive endoderm (DE)7, FOXA2, TBX1, and SOX2 for anterior foregut endoderm (AFE)8, and NKX2-1 for early lung progenitor cells9. In embryonic lung development, the foregut divides into the dorsal esophagus and ventral trachea. The buds of the right and left lungs appear as two independent outpouchings around the tracheal bud10. During branching morphogenesis, the mesenchyme surrounding the epithelium produces elastic tissue, smooth muscle, cartilage, and vasculature11. The interaction between the epithelium and mesenchyme is essential for normal lung development. This includes the secretion of FGF1012 by the mesenchyme and SHH13 produced by the epithelium.
Here, we describe a protocol for the directed differentiation of hiPSCs into three-dimensional (3D) whole lung organoids (WLO). While there are similar approaches that incorporate isolation of lung progenitor cells via sorting at the LPC stage to make alveolar-like14,15 (distal) organoids or airway16 (proximal) organoids, or generate ventral-anterior foregut spheroids to make human lung organoids expressing alveolar-cell and mesenchymal markers and bud tip progenitor organoids17, the strength of this method is the inclusion of both lung epithelial and mesenchymal cell types to pattern and orchestrate lung branching morphogenesis, maturation, and expansion in vitro.
This protocol uses small molecules and growth factors to direct the differentiation of pluripotent stem cells through definitive endoderm, anterior foregut endoderm, and lung progenitor cells. These cells are then induced into 3D whole lung organoids through important developmental steps, including branching and maturation. The summary of the differentiation protocol is shown in Figure 1a with representative brightfield images of endodermal and organoid differentiation shown in Figure 1b. Figure 1c,d show the gene expression details of endodermal differentiation as well as the gene expression of both the proximal and distal populations of lung epithelial cells after completing the differentiation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Cell Culture</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>12 well plates</td>
			<td>Corning</td>
			<td>3512</td>
			<td></td>
		</tr>
		<tr>
			<td>12-well inserts, 0.4um, translucent</td>
			<td>VWR</td>
			<td>10769-208</td>
			<td></td>
		</tr>
		<tr>
			<td>2-mercaptoethanol</td>
			<td>Sigma-Aldrich</td>
			<td>M3148</td>
			<td></td>
		</tr>
		<tr>
			<td>Accutase</td>
			<td>Innovative Cell Tech</td>
			<td>AT104</td>
			<td></td>
		</tr>
		<tr>
			<td>ascorbic acid</td>
			<td>Sigma</td>
			<td>A4544</td>
			<td></td>
		</tr>
		<tr>
			<td>B27 without retinoic acid</td>
			<td>ThermoFisher</td>
			<td>12587010</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine serum albumin (BSA) Fraction V, 7.5% solution</td>
			<td>Gibco</td>
			<td>15260-037</td>
			<td></td>
		</tr>
		<tr>
			<td>Dispase</td>
			<td>StemCellTech</td>
			<td>7913</td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM/F12</td>
			<td>Gibco</td>
			<td>10565042</td>
			<td></td>
		</tr>
		<tr>
			<td>FBS</td>
			<td>Gibco</td>
			<td>10082139</td>
			<td></td>
		</tr>
		<tr>
			<td>Glutamax</td>
			<td>Life Technologies</td>
			<td>35050061</td>
			<td></td>
		</tr>
		<tr>
			<td>Ham&#8217;s F12</td>
			<td>Invitrogen</td>
			<td>11765-054</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Gibco</td>
			<td>15630-080</td>
			<td></td>
		</tr>
		<tr>
			<td>Iscove&#8217;s Modified Dulbecco&#8217;s Medium (IMDM) + Glutamax</td>
			<td>Invitrogen</td>
			<td>31980030</td>
			<td></td>
		</tr>
		<tr>
			<td>Knockout Serum Replacement (KSR)</td>
			<td>Life Technologies</td>
			<td>10828028</td>
			<td></td>
		</tr>
		<tr>
			<td>Matrigel</td>
			<td>Corning</td>
			<td>354230</td>
			<td></td>
		</tr>
		<tr>
			<td>Monothioglycerol</td>
			<td>Sigma</td>
			<td>M6145</td>
			<td></td>
		</tr>
		<tr>
			<td>mTeSR plus Kit (10/case)</td>
			<td>Stem Cell Tech</td>
			<td>5825</td>
			<td></td>
		</tr>
		<tr>
			<td>N2</td>
			<td>ThermoFisher</td>
			<td>17502048</td>
			<td></td>
		</tr>
		<tr>
			<td>NEAA</td>
			<td>Life Technologies</td>
			<td>11140050</td>
			<td></td>
		</tr>
		<tr>
			<td>Pen/strep</td>
			<td>Lonza</td>
			<td>17-602F</td>
			<td></td>
		</tr>
		<tr>
			<td>ReleSR</td>
			<td>Stem Cell Tech</td>
			<td>5872</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI1640 + Glutamax</td>
			<td>Life Technologies</td>
			<td>12633012</td>
			<td></td>
		</tr>
		<tr>
			<td>TrypLE</td>
			<td>Gibco</td>
			<td>12605-028</td>
			<td></td>
		</tr>
		<tr>
			<td>Y-27632 (Rock Inhibitor)</td>
			<td>R&#38;D Systems</td>
			<td>1254/1</td>
			<td></td>
		</tr>
		<tr>
			<td>Growth Factors/Small Molecules</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Activin A</td>
			<td>R&#38;D Systems</td>
			<td>338-AC</td>
			<td></td>
		</tr>
		<tr>
			<td>All-trans retinoic acid (RA)</td>
			<td>Sigma-Aldrich</td>
			<td>R2625</td>
			<td></td>
		</tr>
		<tr>
			<td>BMP4</td>
			<td>R&#38;D Systems</td>
			<td>314-BP/CF</td>
			<td></td>
		</tr>
		<tr>
			<td>Br-cAMP</td>
			<td>Sigma-Aldrich</td>
			<td>B5386</td>
			<td></td>
		</tr>
		<tr>
			<td>CHIR99021</td>
			<td>Abcam</td>
			<td>ab120890</td>
			<td></td>
		</tr>
		<tr>
			<td>Dexamethasone</td>
			<td>Sigma-Aldrich</td>
			<td>D4902</td>
			<td></td>
		</tr>
		<tr>
			<td>Dorsomorphin</td>
			<td>R&#38;D Systems</td>
			<td>3093</td>
			<td></td>
		</tr>
		<tr>
			<td>EGF</td>
			<td>R&#38;D Systems</td>
			<td>236-EG</td>
			<td></td>
		</tr>
		<tr>
			<td>FGF10</td>
			<td>R&#38;D Systems</td>
			<td>345-FG/CF</td>
			<td></td>
		</tr>
		<tr>
			<td>FGF7</td>
			<td>R&#38;D Systems</td>
			<td>251-KG/CF</td>
			<td></td>
		</tr>
		<tr>
			<td>IBMX (3-Isobtyl-1-methylxanthine)</td>
			<td>Sigma-Aldrich</td>
			<td>I5879</td>
			<td></td>
		</tr>
		<tr>
			<td>SB431542</td>
			<td>R&#38;D Systems</td>
			<td>1614</td>
			<td></td>
		</tr>
		<tr>
			<td>VEGF/PIGF</td>
			<td>R&#38;D Systems</td>
			<td>297-VP/CF</td>
			<td></td>
		</tr>
		<tr>
			<td>Primary antibodies</td>
			<td></td>
			<td></td>
			<td>Dilution rate</td>
		</tr>
		<tr>
			<td>CXCR4-PE</td>
			<td>R&#38;D Systems</td>
			<td>FAB170P</td>
			<td>1:200 (F)</td>
		</tr>
		<tr>
			<td>HOPX</td>
			<td>Santa Cruz Biotech</td>
			<td>sc-398703</td>
			<td>0.180555556</td>
		</tr>
		<tr>
			<td>HTII-280</td>
			<td>Terrace Biotech</td>
			<td>TB-27AHT2-280</td>
			<td>0.145833333</td>
		</tr>
		<tr>
			<td>KRT5</td>
			<td>Abcam</td>
			<td>ab52635</td>
			<td>0.180555556</td>
		</tr>
		<tr>
			<td>NKX2-1</td>
			<td>Abcam</td>
			<td>ab76013</td>
			<td>0.25</td>
		</tr>
		<tr>
			<td>NKX2-1-APC</td>
			<td>LS-BIO</td>
			<td>LS-C264437</td>
			<td>1:1000 (F)</td>
		</tr>
		<tr>
			<td>proSPC</td>
			<td>Abcam</td>
			<td>ab40871</td>
			<td>0.215277778</td>
		</tr>
		<tr>
			<td>SCGB3A2</td>
			<td>Abcam</td>
			<td>ab181853</td>
			<td>0.25</td>
		</tr>
		<tr>
			<td>SOX2</td>
			<td>Invitrogen</td>
			<td>MA1-014</td>
			<td>0.180555556</td>
		</tr>
		<tr>
			<td>SOX9</td>
			<td>R&#38;D Systems</td>
			<td>AF3075</td>
			<td>0.180555556</td>
		</tr>
		<tr>
			<td>SPB (mature)</td>
			<td>7 Hills</td>
			<td>48604</td>
			<td>1: 1500 (F) 1:500 (W)a</td>
		</tr>
		<tr>
			<td>SPC (mature)</td>
			<td>LS Bio</td>
			<td>LS-B9161</td>
			<td>1:100 (F); 1:500 (W) a</td>
		</tr>
	</tbody>
</table>

generation of 3d whole lung organoids from induced pluripotent stem cells for modeling lung developmental biology and disease

Human lung development and disease has been difficult to study due to the lack of biologically relevant in vitro model systems. Human induced pluripotent stem cells (hiPSCs) can be differentiated stepwise into 3D multicellular lung organoids, made of both epithelial and mesenchymal cell populations. We recapitulate embryonic developmental cues by temporally introducing a variety of growth factors and small molecules to efficiently generate definitive endoderm, anterior foregut endoderm, and subsequently lung progenitor cells. These cells are then embedded in growth factor reduced (GFR)-basement membrane matrix medium, allowing them to spontaneously develop into 3D lung organoids in response to external growth factors. These whole lung organoids (WLO) undergo early lung developmental stages including branching morphogenesis and maturation after exposure to dexamethasone, cyclic AMP and isobutylxanthine. WLOs possess airway epithelial cells expressing the markers KRT5 (basal), SCGB3A2 (club) and MUC5AC (goblet) as well as alveolar epithelial cells expressing HOPX (alveolar type I) and SP-C (alveolar type II). Mesenchymal cells are also present, including smooth muscle actin (SMA), and platelet-derived growth factor receptor A (PDGFR&#945;). iPSC derived WLOs can be maintained in 3D culture conditions for many months and can be sorted for surface markers to purify a specific cell population. iPSC derived WLOs can also be utilized to study human lung development, including signaling between the lung epithelium and mesenchyme, to model genetic mutations on human lung cell function and development, and to determine the cytotoxicity of infective agents.

24 hours after plating, day 1, iPSCs should be 50%-90% confluent. On day 2, DE should be 90%-95% confluent. During DE induction, it is common to observe significant cell death on day 4 but attached cells will retain a compact cobblestone morphology (Figure 2b). Discontinue differentiation if the majority of adherent cells detach and consider shortening exposure to DE media with activin A by 6-12 h. During AFE induction, cell death is minimal, and cells remain adherent, but will appear smalle...

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Generation of 3D Whole Lung Organoids from Induced Pluripotent Stem Cells for Modeling Lung Developmental Biology and Disease

The article describes step wise directed differentiation of induced pluripotent stem cells to three-dimensional whole lung organoids containing both proximal and distal epithelial lung cells along with mesenchyme.

Human lung development and disease has been difficult to study due to the lack of biologically relevant in vitro model systems. Human induced pluripotent ...

This protocol uses induced pluripotent stem cells to differentiate them into lung cells in order to model human lung disease and development in a dish. This protocol is significant because it's difficult to obtain and culture primary human lung tissue. The main advantages of differentiating lung cells from pluripotent stem cells is to have a constant supply of specific lung cells to study human lung development and disease.These cells can be maintained in cell culture for long periods of time, can be cryopreserved for future applications, and can be genetically manipulated to study gene mutations. Demonstrating the procedure will be Rachel McVicar, a PhD candidate from my laboratory. Before starting the experiment, slowly thaw a growth factor reduced, or GFR, basement membrane matrix medium on ice, and dilute it in an equal volume of cold DMEM F12.Place P1000 tips in the freezer to chill prior to use. Next, coat each well of a 12 well plate with 500 microliters of the 50%GFR basement membrane matrix medium, and remove any excess medium mixture and bubbles from the wells. Place the well plates on top of wet ice or a refrigerator at four degree Celsius to set for 20 minutes, then move the plate to the 37 degree Celsius incubator overnight.When high PSEs reach 70%confluency, add 10 micromolar ROCK inhibitor Y27632 to human induced pluripotent stem cells, and wait an hour prior to dissociation. Aspirate the media, and wash the cells once with PVS. Dissociate IPSCs by adding 500 microliters of cell detachment medium per well, and incubate for 20 minutes at 37 degrees Celsius in a 5%carbon dioxide incubator.After the incubation, add 500 microliters of stem cell passaging medium per well. Gently pipette cells using a P1000 tip to obtain a single cell suspension. Then transfer the dissociated cells into a 15 milliliter tube and centrifuge for five minutes at 300 times G.Following centrifugation, aspirate the medium, and resuspend the cell pellet with one milliliter of mTeSR Plus media supplemented with 10 micromolar ROCK inhibitor.After counting the cells, add two times 10 to the fifth IPSCs to each well of a 12 well GFR medium coated plate, and incubate overnight at 37 degrees Celsius. On the next day, aspirate the mTeSR Plus before adding definitive endoderm, or DE, induction media. On days two and three, change the DE induction media.On day four, begin AFE induction by replacing DE induction media with serum-free basal medium. Change AFE medium daily for three days before analyzing AFE efficiency at the end of day six. On day seven, thaw GFR basement membrane matrix medium on ice for later use.Simultaneously, proceed with lung progenitor cell differentiation by aspirating the AFE media and washing the wells with PVS. Add one milliliter of cell detachment solution to the well and incubate for 10 minutes at 37 degrees Celsius. After incubation, add one milliliter of quenching media to the Wells containing cell detachment solution.Keep cells as aggregates by gently pipetting up and down. Make sure all cells are dislodged, but for transferring them into a 15 milliliter conical tube for centrifugation at 300 times G for five minutes. Remove supernatant and resuspend the cell pellet in LPC induction media.Count the cells, and add 2.5 times 10 to the fifth cells to 100 microliters of cold GFR basement membrane matrix medium, and mix well. Place a droplet into a well of a 12-well plate and incubate at 37 degree Celsius for 30 to 60 minutes. Next, add one milliliter of LPC media per well, ensuring that the medium drop is fully submerged and incubate overnight at 37 degrees Celsius.On day eight, change LPC medium to remove ROCK inhibitor Y27632. Keep changing the media every other day and analyze LPC efficiency at the end of day 16. On day 17, wash wells and add 500 microliters of two microgram per milliliter dispase.Pipette the dispase mixture with a P1000 pipette and incubate for 15 minute, then pipette the mixture and incubate for another 15 minutes. Following incubation, add one milliliter of the quenching media to the dispase containing wells, and transfer the cells into conical tubes. Centrifuge and resuspend the pellet in one milliliter of chilled PVS, then repeat the centrifugation.Then resuspend the pellet in one milliliter of cell detachment medium. Incubate the cells at 37 degree Celsius for 12 minutes, then add an equal volume of quenching media and centrifuge again. Resuspend the pellet in one milliliter of quenching media and 10 micromolar ROCK inhibitor Y27632.Perform a cell count to calculate the volume needed to obtain eight times 10 to the fourth cells per well. Then aliquot required volume of LPC cell aggregates into 1.5 milliliter micro centrifuge tubes, and centrifuge for five minutes at 300 times G.Remove excess supernatant without agitating the cell pellet, leaving 10 microliters of residual media. Resuspend the cell pellet in 200 microliters of cold GFR basement membrane matrix medium and transfer the cells to cell culture membrane inserts.Incubate at 37 degrees Celsius for 30 to 60 minutes. After incubation, add one milliliter of 3D organoid induction medium to the basolateral chamber of the insert, and replace it with fresh medium every other day for six days. On day 23, switch the medium to 3D branching medium, then change the medium every other day for six days.On day 29, change to 3D maturation medium, and continue replacing the medium every other day for the next six days. On day four of DE induction, attached cells display a compact cobblestone morphology. The definitive endoderm markers CXCR4 and SOX17 overlaid with nuclei was expressed, confirming endodermal differentiation.Anterior foregut induction was confirmed on day seven with the morphology showing more tightly compacted cells, and the markers FOXA2 and SOX2 overlaid with nuclei. The generation of 3D lung progenitor cells was confirmed with 3D spheroids, and the endogenous expression of NKX2-1 GFP in a reporter cell line. After a three week differentiation into whole lung organoids, the lung markers were analyzed by immunocytochemistry.Markers for branching morphogenesis SOX2 and SOX9 overlaid by nuclei was observed in the organoids. Proximal lung markers P63 and KRT5, both markers of basal cells, were successfully detected along with SCGB3A2, which is a marker for club cells. Distal lung markers induced Pro SPC and SPB markers for Alveolar Type II cells.And HOPX markers of Alveolar Type I cells. Additionally, NKX2-1 and ZO1 were expressed overlaid with nuclei. The Mesenchyme lung cell markers PGFR Alpha, a marker for fibroblasts, co-expressed with SOX9, represented distal mesenchyme.Vimentin was also expressed and was dispersed throughout the lung. Following this procedure, the lung organoids can be invested with induced pluripotent stem cell derived endothelial and immune cells. Lung development and disease occurs by a signaling between the epithelial and mesenchymal cell populations, but also from endothelial cells and macrophages.A 3D lung tissue model system is clinically relevant to study human disease and therapeutics.

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7.5K 조회수.  University of California, San Diego School of Medicine. 이 프로토콜은 유도 된 다능성 줄기 세포를 사용하여 인간의 폐 질환과 접시의 발달을 모델링하기 위해 폐 세포로 분화합니다. 이 프로토콜은 1 차적인 인간 폐 조직을 얻고 배양하기 어렵기 때문에 중요합니다. 만능 줄기 세포에서 폐 세포를 분화의 주요 장점은 인간의 폐 발달 과 질병을 연구하기 위해 특정 폐 세포의 지속적인 공급을 갖는 것입니다.이 세포는 오랜 기...