This work was supported by the HIT-CF program of the Dutch CF foundation (NCFS), ZonMW (40-00812-98-14103), the Wilhelmina Children&#39;s Hospital Research Fund and CZ, and Zilverenkruis/Achmea. We would like to thank S. Heida-Michel, M. Geerdink, K.M. de Winter-de Groot, and G. Berkers (Department of Pediatric Pulmonology, Wilhelmina Children&#39;s Hospital, UMC Utrecht), and R.H.J. Houwen (Department of Pediatric Gastroenterology, Wilhelmina Children&#39;s Hospital, UMC Utrecht) for approaching the patients and getting the biopsies for the generation of a CF Biobank.

<ol>
	<li>De Boeck, K., Amaral, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progress+in+therapies+for+cystic+fibrosis.">Progress in therapies for cystic fibrosis.</a> Lancet Respir Med. 4 (8), 662-674 (2016).</li><li>Cutting, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cystic+fibrosis+genetics:+from+molecular+understanding+to+clinical+application.">Cystic fibrosis genetics: from molecular understanding to clinical application.</a> Nature Rev Genet. 16 (1), 45-56 (2015).</li><li>Sosnay, P. R., Siklosi, K. R., 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=Defining+the+disease+liability+of+variants+in+the+cystic+fibrosis+transmembrane+conductance+regulator+gene.">Defining the disease liability of variants in the cystic fibrosis transmembrane conductance regulator gene.</a> Nature Genet. 45 (10), 1160-1167 (2013).</li><li>Zielenski, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genotype+and+phenotype+in+cystic+fibrosis.">Genotype and phenotype in cystic fibrosis.</a> Respiration. 67 (2), 117-133 (2000).</li><li>Van Goor, F., Hadida, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rescue+of+CF+airway+epithelial+cell+function+in+vitro+by+a+CFTR+potentiator,+VX-770.">Rescue of CF airway epithelial cell function in vitro by a CFTR potentiator, VX-770.</a> Proc Natl Acad Sci U.S.A. 106 (44), 18825-18830 (2009).</li><li>Van Goor, F., Hadida, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Correction+of+the+F508del-CFTR+protein+processing+defect+in+vitro+by+the+investigational+drug+VX-809.">Correction of the F508del-CFTR protein processing defect in vitro by the investigational drug VX-809.</a> Proc Natl Acad Sci U.S.A. 108 (46), 18843-18848 (2011).</li><li>Accurso, F. 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W., Davies, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+CFTR+potentiator+in+patients+with+cystic+fibrosis+and+the+G551D+mutation.">A CFTR potentiator in patients with cystic fibrosis and the G551D mutation.</a> N Engl J Med. 365 (18), 1663-1672 (2011).</li><li>De Boeck, K., Munck, A., 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=Efficacy+and+safety+of+ivacaftor+in+patients+with+cystic+fibrosis+and+a+non-G551D+gating+mutation.">Efficacy and safety of ivacaftor in patients with cystic fibrosis and a non-G551D gating mutation.</a> J Cyst Fibros. 13 (6), 674-680 (2014).</li><li>Boyle, M. P., Bell, S. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+CFTR+corrector+(lumacaftor)+and+a+CFTR+potentiator+(ivacaftor)+for+treatment+of+patients+with+cystic+fibrosis+who+have+a+phe508del+CFTR+mutation:+a+phase+2+randomised+controlled+trial.">A CFTR corrector (lumacaftor) and a CFTR potentiator (ivacaftor) for treatment of patients with cystic fibrosis who have a phe508del CFTR mutation: a phase 2 randomised controlled trial.</a> Lancet Respir Med. 2 (7), 527-538 (2014).</li><li>Wainwright, C. E., Elborn, J. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lumacaftor-Ivacaftor+in+Patients+with+Cystic+Fibrosis+Homozygous+for+Phe508del+CFTR.">Lumacaftor-Ivacaftor in Patients with Cystic Fibrosis Homozygous for Phe508del CFTR.</a> N Engl J Med. 373 (3), 220-231 (2015).</li><li>Van Goor, F., Yu, H., Burton, B., Hoffman, B. 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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=Long-term+expansion+of+epithelial+organoids+from+human+colon,+adenoma,+adenocarcinoma,+and+Barrett's+epithelium.">Long-term expansion of epithelial organoids from human colon, adenoma, adenocarcinoma, and Barrett's epithelium.</a> Gastroenterology. 141 (5), 1762-1772 (2011).</li><li>Clevers, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+development+and+disease+with+Organoids.">Modeling development and disease with Organoids.</a> Cell. 165 (7), 1586-1597 (2016).</li><li>Dekkers, J. F., Wiegerinck, C. 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Hans Clevers is an inventor on patents for organoid culture and the Forskolin-induced swelling assay. Jeffrey M Beekman is an inventor on a patent for the Forskolin-induced swelling assay. Sylvia F Boj and Robert Vries are employed by the Foundation Hubrecht Organoid Technology (HUB), which holds the exclusive license to the Organoid Technology. Otherwise, the authors have nothing to disclose.

Here, we provide a complete protocol for the generation, expansion, freezing, and thawing of human colorectal organoids. While we have established human organoid cultures some time ago17, it has sometimes proven difficult to establish the technology in other labs without hands-on training. We anticipate that these protocols will replace such training.
Wnt-3A-conditioned medium is one of the most crucial reagents in order to succeed in establishing and maintaining a long...

CF is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that encodes an epithelial anion channel. CF affects approximately 85,000 people worldwide1. Over 2,000 CFTR mutations have been identified (<a href="http://www.genet.sickkids.on.ca">www.genet.sickkids.on.ca</a>). This diversity partially explains a wide spectrum of observed disease phenotypes (<a href="http://www.CFTR2.org">www.CFTR2.org</a>)2,3. Six classes of CFTR mutations are defined based on their effect on CFTR protein expression and function: (I) no synthesis, (II) impaired trafficking, (III) defective channel gating, (IV) altered conductance, (V) reduced levels of normally functioning CFTR, and (VI) impaired cell surface stability4. Although the common CFTR mutations are well studied, CFTR function and relation with clinical status remain poorly understood at the level of the individual, particularly for the large group of rare &#34;orphan&#34; mutations (<a href="http://www.CFTR2.org">www.CFTR2.org</a>)1,3.
Recently, drugs have been developed that target the CFTR protein in a mutation-specific fashion. Two classes of CFTR protein-targeting drugs are currently in clinical use and have distinct modes of action. Potentiators, such as VX-770, enhance the open-probability of apically-localized mutant CFTR and act directly upon their addition to cells5. Correctors, such as VX-809, restore the trafficking of endoplasmic reticulum-localized misfolded CFTR and require pre-incubation with cells before the effects are observed6. The CFTR potentiator, VX-770, has been registered for subjects with the G551D mutation7,8, as well as for eight other CFTR gating mutations, including S1251N9; together, these mutations are carried by 5% of all CF subjects. Other clinical trials have indicated that VX-770, combined with the corrector VX-809, has limited yet significant effects on lung function and causes a decrease in exacerbation rates in subjects homozygous for the F508del mutation carried by 45-50% of patients10,11.
Conventional clinical trials to identify drug-responsive subjects within the remaining 50% of CF patients are costly and time-consuming and are not feasible for individuals with extremely rare CFTR genotypes. Novel, cost-effective, personalized methods are crucial to match the increasing number of CFTR modulators to individuals carrying any type of CFTR mutation. Until now, the trial inclusion of patient groups carrying specific CFTR mutations has been guided by studies using mutant CFTR gene transfection in heterologous cell systems, followed by electrophysiological studies in Ussing chambers5,6,12. Due to a lack of adequate CF animal models, drug efficacy studies in air-liquid-interface-differentiated bronchial epithelial cells derived from CF lung explant materials have been used for drug development13,14,15. However, the limited availability of lung explant tissues and the invasive procedures to obtain bronchial cells from subjects without end-stage disease hamper the analysis of less common CFTR mutations and prevent drug testing in a personalized fashion. To overcome these limitations, &#34;easy access&#34; tissues, such as colorectal organoids, nasal airway cells, and airway cells derived from induced pluripotent stem cells, are currently being explored for personalized drug treatments.
Previously, we established protocols to culture epithelial stem cells from any gastrointestinal organ in the form of 3D organoids16,17. For the human colon/rectum, the culture conditions involve defined growth factors (Epithelial Growth Factor (EGF), Gastrin, Wnt-3A, R-spondin 3 (Rspo3), and Noggin) combined with small molecules (Nicotinamide, A83-01, and SB202190) in a basement membrane matrix. Under these conditions, single stem cells or small tissue fragments grow out into closed, cystic, 3D structures formed by highly-polarized epithelium with its basal side oriented towards the outside. All cell types typically appear in their normal ratios and positions. Organoids can be expanded over long time periods by weekly mechanical disruption and re-plating. They are genetically and phenotypically stable and can be stored, allowing long-term expansion and bio-banking17. They are amenable to all standard cell-biological/genetic manipulations and analytical techniques developed for 2D cell lines18.
We recently demonstrated that CFTR function can be readily measured in colorectal organoids in a forskolin-induced swelling (FIS) assay19,20. When exposed to forskolin (Fsk) or, alternatively, to cholera toxin, organoids rapidly increase their cyclic adenosine monophosphate (cAMP) levels, which in turn results in the opening of the CFTR channel19. Organoids from healthy individuals, or from subjects with CFTR mutations associated with residual function, will subsequently swell as a consequence of ion and water transport to the organoid lumen, the in vitro equivalent of secretory diarrhea. The FIS response of colorectal organoids was previously shown to be fully CFTR-dependent, as indicated by organoids derived from CFTR-null individuals and by the use of specific pharmacological CFTR inhibitors19. Large subject-specific data sets can be derived within several weeks after taking a biopsy.
For the FIS assay described in detail here, organoids are cultured from rectal biopsies that can be obtained at any age and with only limited discomfort21. Organoids are passaged weekly by mechanical disruption into single crypts that easily reseal and form new organoids. For running the FIS assay, ~30-80 of these disrupted little organoids are plated in each well of a 96-well plate19. At the day of the assay, the organoids are stained with calcein green, a fluorescent cell-permeable dye that it is retained within living cells, facilitating live imaging. Then, Fsk, which raises intracellular cAMP and thereby activates CFTR, is added in order to stimulate organoid swelling. Potentiators that act upon apical CFTR are added simultaneously with the forskolin, whereas correctors that restore CFTR trafficking are added 24 hr before the addition of Fsk. The organoid swelling is quantified by an automated image analysis that calculates the relative increase in the total area of all fluorescent objects for each time point upon forskolin addition.
3D organoid swelling provides advantages and disadvantages over existing electrophysiological CFTR readouts in 2D cultured airway cells in Ussing chambers. A major advantage is the throughput of the swelling assay. Cells are cultured and assayed using a single type of culture medium, and an experienced technician can culture up to 25 organoid samples on a weekly basis while quantifying approximately 1,200 data points per week in 12 patient samples. We conventionally type a single experimental condition by duplicate or triplicate measurements per plate and repeat such measurements at three independent incubation time points. In total, approximately 300-500 single organoid structures are then measured per experimental condition, which leads to very precise measurements of CFTR function with limited technical variability. This precision allows us to clearly define differences in residual function and response to CFTR modulators and allows us to readily pick up genetic background effects between patients carrying identical CFTR mutations19,22,23,24,25. Data quality can be easily assessed from microscope images. While FIS is fully CFTR-dependent, it is an indirect outcome measure for CFTR function, its read-out caused by the coupling of ion transport to fluid transport. This contrasts with direct CFTR function measurements in Ussing chambers, which measure transepithelial ion currents26. Ussing chambers allow the select stimulation of apical or basolateral compartments (which the organoid assay does not allow); by permeabilizing basolateral membranes, the apical CFTR-dependent anion secretion can be selectively measured27.

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	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">Advanced Dulbecco&#8217;s Modified Eagles Medium with Nutrient Mixture F-12 Hams (Ad-DF) 500ml&#160;</td>
			<td style="width:180px;">Thermo Fisher Scientific:&#160; Invitrogen</td>
			<td style="width:119px;">#12634</td>
			<td style="width:399px;">stored at 4 &#176;C</td>
		</tr>
		<tr height="44">
			<td height="44" style="height:44px;width:355px;">GlutaMax</td>
			<td style="width:180px;">Thermo Fisher Scientific:&#160; Invitrogen</td>
			<td style="width:119px;">#35050</td>
			<td style="width:399px;">stored at 4 &#176;C</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">Hepes</td>
			<td style="width:180px;">Thermo Fisher Scientific:&#160; Invitrogen</td>
			<td style="width:119px;"># 15630-056</td>
			<td style="width:399px;">stored at 4 &#176;C</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">Penicillin/Streptomycin</td>
			<td style="width:180px;">Thermo Fisher Scientific:&#160; Invitrogen</td>
			<td style="width:119px;">#15140-122</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">96 well culture plate</td>
			<td style="width:180px;">Cellstar</td>
			<td style="width:119px;">#655180</td>
			<td style="width:399px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">24 well culture plate</td>
			<td style="width:180px;">Cellstar</td>
			<td style="width:119px;">#662160</td>
			<td style="width:399px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">6 well culture plate</td>
			<td style="width:180px;">Cellstar</td>
			<td style="width:119px;">#657160</td>
			<td style="width:399px;"></td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:355px;">Dulbecco&#39;s Phosphate Buffered Saline (-) CaCl2 (-) MgCl2) (DPBS)</td>
			<td style="width:180px;">Life Technologies: Gibco</td>
			<td style="width:119px;">#14190-094</td>
			<td style="width:399px;">stored at 4 &#176;C</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">Dulbecco&#8217;s Modified Eagles Medium&#160; (DMEM) 500ml&#160;</td>
			<td style="width:180px;">Thermo Fisher Scientific:&#160; Invitrogen</td>
			<td style="width:119px;">#31966-021</td>
			<td style="width:399px;">For Wnt-3A Conditioned Medium Production. Stored at 4 &#176;C</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:355px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:180px;">Bovogen</td>
			<td style="width:119px;">#SFBS LOT#11113</td>
			<td style="width:399px;">For Wnt-3A Conditioned Medium Production. Stored at -20 &#176;C</td>
		</tr>
		<tr height="43">
			<td height="43" style="height:43px;width:355px;">L Wnt3A cell line</td>
			<td style="width:180px;">ATCC</td>
			<td style="width:119px;">#CRL-2647</td>
			<td style="width:399px;">For Wnt-3A Conditioend Medium Production.</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:355px;">TOP/FOP plasmids</td>
			<td style="width:180px;">Millipore&#160;</td>
			<td style="width:119px;">#17-285</td>
			<td style="width:399px;">For measuring Wnt activity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">pTK-Renilla</td>
			<td style="width:180px;">Promega&#160;</td>
			<td style="width:119px;">#E2241</td>
			<td style="width:399px;">For measuring Wnt activity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">HEK-293</td>
			<td style="width:180px;">ATCC</td>
			<td style="width:119px;">#CRL-1573</td>
			<td style="width:399px;">For measuring Wnt activity</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Dual-Luciferase Reporter Assay System</td>
			<td style="width:180px;">Promega&#160;</td>
			<td style="width:119px;">#E1910</td>
			<td style="width:399px;">For measuring Wnt activity</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">Zeocin&#160;</td>
			<td style="width:180px;">Thermo Fisher Scientific:&#160; Invitrogen</td>
			<td style="width:119px;">#R250-01</td>
			<td style="width:399px;">For Wnt-3A Cell line selection</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">B27 supplement&#160;</td>
			<td style="width:180px;">Thermo Fisher Scientific:&#160; Invitrogen</td>
			<td style="width:119px;">#17504-044</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">N-Acetylcysteine</td>
			<td style="width:180px;">Sigma Aldrich</td>
			<td style="width:119px;">#A9165-5G</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Nicotinamide</td>
			<td style="width:180px;">Sigma Aldrich</td>
			<td style="width:119px;">#N0636</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:355px;">Human Epithelial Growth Factor (hEGF)</td>
			<td style="width:180px;">PrepoTech</td>
			<td style="width:119px;">#AF-100-15</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="46">
			<td height="46" style="height:46px;width:355px;">Gastrin</td>
			<td style="width:180px;">Sigma Aldrich</td>
			<td style="width:119px;">#G9145</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">TGFb type I Receptor inhibitor (A83-01)&#160;</td>
			<td style="width:180px;">Tocris</td>
			<td style="width:119px;">#2939</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Y-27632 dihydrochloride (RhoKi)</td>
			<td style="width:180px;">Selleckchem</td>
			<td style="width:119px;">#S1049</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">p38 MAPK inhibitor (p38i) (SB202190)</td>
			<td style="width:180px;">Sigma Aldrich</td>
			<td style="width:119px;">#S7067</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Primocin</td>
			<td style="width:180px;">InvivoGen</td>
			<td style="width:119px;">#ant-pm-1</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Human Noggin (hNoggin)</td>
			<td style="width:180px;">PrepoTech</td>
			<td style="width:119px;">#120-10C</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Human R-spondin 3 (hRspo-3)</td>
			<td style="width:180px;">R&#38;D Systems</td>
			<td style="width:119px;">#3500-RS/CF</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Vancomycin</td>
			<td style="width:180px;">Sigma Aldrich</td>
			<td style="width:119px;">#861987- 250mg</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Gentamycin</td>
			<td style="width:180px;">Life Technologies: Gibco</td>
			<td style="width:119px;">#15710-049</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:355px;">Ethylenediamine tetraacetic acid (EDTA)</td>
			<td style="width:180px;">Sigma Aldrich</td>
			<td style="width:119px;">#431788</td>
			<td style="width:399px;">Stored at 4 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Matrigel</td>
			<td style="width:180px;">Corning</td>
			<td style="width:119px;">#354230</td>
			<td style="width:399px;">stored at -80 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">TryplE Express&#160;</td>
			<td style="width:180px;">Life Technologies: Gibco</td>
			<td style="width:119px;">#12605-010</td>
			<td style="width:399px;">for trypsinizing organoids for freezing</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Recovery Cell Culture Freezing Medium</td>
			<td style="width:180px;">Life Technologies: Gibco</td>
			<td style="width:119px;">#12648010</td>
			<td style="width:399px;">for freezing</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Calcein</td>
			<td style="width:180px;">Life Technologies: Gibco</td>
			<td style="width:119px;">#C3100MP</td>
			<td style="width:399px;">stored at -20 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Forskolin</td>
			<td style="width:180px;">R&#38;D Systems</td>
			<td style="width:119px;">#1099-50 mg</td>
			<td style="width:399px;">stored at -80 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Lumacaftor (VX-809)</td>
			<td style="width:180px;">Selleckchem</td>
			<td style="width:119px;">#s1565</td>
			<td style="width:399px;">stored at -80 &#176;C</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Ivacaftor (VX-770)</td>
			<td style="width:180px;">Selleckchem</td>
			<td style="width:119px;">#s1144</td>
			<td style="width:399px;">stored at -80 &#176;C</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">Name of Reagents/Material</td>
			<td style="width:180px;">Solvent</td>
			<td style="width:119px;">Stock Concentration</td>
			<td style="width:399px;">Final Concentration</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">GlutaMax</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">200 mM</td>
			<td style="width:399px;">2m M</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Hepes</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">1 M</td>
			<td style="width:399px;">10 mM</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:355px;">Penicillin/Streptomycin</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">10K U/ml 10K &#181;g/ml</td>
			<td style="width:399px;">100 U/ml 100 &#181;g/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Zeocin&#160;</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">100 mg/ml&#160;</td>
			<td style="width:399px;">125 &#181;g/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">B27 supplement&#160;</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">100 x</td>
			<td style="width:399px;">1 x</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:355px;">N-Acetylcysteine</td>
			<td style="width:180px;">MiliQ H20</td>
			<td style="width:119px;">500 mM</td>
			<td style="width:399px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Nicotinamide</td>
			<td style="width:180px;">DPBS</td>
			<td style="width:119px;">1 M</td>
			<td style="width:399px;">10 mM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Human Epithelial Growth Factor (hEGF)</td>
			<td style="width:180px;">DPBS 0.1%BSA</td>
			<td style="width:119px;">0.5 mg/ml</td>
			<td style="width:399px;">50 ng/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Gastrin</td>
			<td style="width:180px;">DPBS</td>
			<td style="width:119px;">100 &#181;M</td>
			<td style="width:399px;">10 nM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">TGFb type I Receptor inhibitor (A83-01)&#160;</td>
			<td style="width:180px;">DMSO</td>
			<td style="width:119px;">5 mM</td>
			<td style="width:399px;">500 nM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Y-27632 dihydrochloride (RhoKi)</td>
			<td style="width:180px;">DMSO</td>
			<td style="width:119px;">10 mM</td>
			<td style="width:399px;">10 &#181;M</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">p38 MAPK inhibitor (p38i) (SB202190)</td>
			<td style="width:180px;">DMSO</td>
			<td style="width:119px;">30 mM</td>
			<td style="width:399px;">10 &#181;M</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Primocin</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">50 mg/ml&#160;</td>
			<td style="width:399px;">100 &#181;g/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Human Noggin (hNoggin)</td>
			<td style="width:180px;">DPBS 0.1%BSA</td>
			<td style="width:119px;">100 &#181;g/ml</td>
			<td style="width:399px;">100 ng/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Human R-spondin 3 (hRspo-3)</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">varies per lot</td>
			<td style="width:399px;">300 ng/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Vancomycin</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">10 mg/ml</td>
			<td style="width:399px;">50 &#181;g/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Gentamycin</td>
			<td style="width:180px;"></td>
			<td style="width:119px;">10 mg/ml</td>
			<td style="width:399px;">50 &#181;g/ml</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:355px;">Ethylenediamine tetraacetic acid (EDTA)</td>
			<td style="width:180px;">MiliQ H20</td>
			<td style="width:119px;">0.5 M</td>
			<td style="width:399px;">2 mM</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Calcein</td>
			<td style="width:180px;">DMSO</td>
			<td style="width:119px;">10 &#181;g/ml</td>
			<td style="width:399px;">3.3 ng/ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Forskolin</td>
			<td style="width:180px;">DMSO</td>
			<td style="width:119px;">10 mM</td>
			<td style="width:399px;">variable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Lumacaftor (VX-809)</td>
			<td style="width:180px;">DMSO</td>
			<td style="width:119px;">20 mM</td>
			<td style="width:399px;">variable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:355px;">Ivacaftor (VX-770)</td>
			<td style="width:180px;">DMSO</td>
			<td style="width:119px;">20 mM</td>
			<td style="width:399px;">variable</td>
		</tr>
	</tbody>
</table>

forskolin-induced swelling in intestinal organoids: an in vitro assay for assessing drug response in cystic fibrosis patients

Recently-developed cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drugs correct surface expression and/or function of the mutant CFTR channel in subjects with cystic fibrosis (CF). Identification of subjects that may benefit from these drugs is challenging because of the extensive heterogeneity of CFTR mutations, as well as other unknown factors that contribute to individual drug efficacy. Here, we describe a simple and relatively rapid assay for measuring individual CFTR function and response to CFTR modulators in vitro. Three dimensional (3D) epithelial organoids are grown from rectal biopsies in standard organoid medium. Once established, the organoids can be bio-banked for future analysis. For the assay, 30-80 organoids are seeded in 96-well plates in basement membrane matrix and are then exposed to drugs. One day later, the organoids are stained with calcein green, and forskolin-induced swelling is monitored by confocal live cell microscopy at 37 &#176;C. Forskolin-induced swelling is fully CFTR-dependent and is sufficiently sensitive and precise to allow for discrimination between the drug responses of individuals with different and even identical CFTR mutations. In vitro swell responses correlate with the clinical response to therapy. This assay provides a cost-effective approach for the identification of drug-responsive individuals, independent of their CFTR mutations. It may also be instrumental in the development of future CFTR modulators.

Figure 1A shows a representative fresh isolation of crypts embedded on BMM. The crypts are from a colorectal biopsy of a CF subject. Usually, an organoid is generated from each crypt (Figure 1A-C). Due to the dysfunction of the CFTR, most of the colon CF organoids are not cystic, but rather are compact and with projections and buddings (Figure 2A-2B). However, some CF organoid cultures, especially with hi...

Watch this Scientific Journal Video about Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients at JoVE.com

Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients

This protocol describes an assay for measuring CFTR function and CFTR modulator responses in cultured tissue from subjects with cystic fibrosis (CF). Biopsy-derived intestinal organoids swell in a cAMP-driven fashion, a response that is defective (or strongly reduced) in CF organoids and can be restored by exposure to CFTR modulators.

Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients

Recently-developed cystic fibrosis transmembrane conductance regulator (CFTR)-modulating drugs correct surface expression and/or function of the mutant ...

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19.1K Views.  Foundation Hubrecht Organoid Technology. This protocol describes an assay for measuring CFTR function and CFTR modulator responses in cultured tissue from subjects with cystic fibrosis (CF). Biopsy-derived intestinal organoids swell in a cAMP-driven fashion, a response that is defective (or strongly reduced) in CF organoids and can be restored by exposure to CFTR modulators.

Video: Forskolin-induced Swelling in Intestinal Organoids: An In Vitro Assay for Assessing Drug Response in Cystic Fibrosis Patients

Assessing Teratogenic Changes in a Zebrafish Model of Fetal Alcohol Exposure

Fetal alcohol syndrome (FAS) is a severe manifestation of embryonic exposure to ethanol. It presents with characteristic defects to the face and organs, including mental retardation due to disordered and damaged brain development. Fetal alcohol spectrum disorder (FASD) is a term used to cover a continuum of birth defects that occur due to maternal alcohol consumption, and occurs in approximately 4% of children born in the United States. With 50% of child-bearing age women reporting consumption of alcohol, and half of all pregnancies being unplanned, unintentional exposure is a continuing issue2. In order to best understand the damage produced by ethanol, plus produce a model with which to test potential interventions, we developed a model of developmental ethanol exposure using the zebrafish embryo. Zebrafish are ideal for this kind of teratogen study3-8. Each pair lays hundreds of eggs, which can then be collected without harming the adult fish. The zebrafish embryo is transparent and can be readily imaged with any number of stains. Analysis of these embryos after exposure to ethanol at different doses and times of duration and application shows that the gross developmental defects produced by ethanol are consistent with the human birth defect. Described here are the basic techniques used to study and manipulate the zebrafish FAS model.

In order to understand the molecular mechanisms of the ethanol-induced developmental damage, we have developed a zebrafish model of ethanol exposure and are exploring the physical, cellular, and genetic alterations that occur after ethanol exposure1. We then seek to find potential interventions and rapidly test them in this animal model.

Fetal alcohol syndrome (FAS) is a severe manifestation of embryonic exposure to ethanol. It presents with characteristic defects to the face and organs, ...

Assessing Transmissible Spongiform Encephalopathy Species Barriers with an In Vitro Prion Protein Conversion Assay

Studies to understanding interspecies transmission of transmissible spongiform encephalopathies (TSEs, prion diseases) are challenging in that they typically rely upon lengthy and costly in vivo animal challenge studies. A number of in vitro assays have been developed to aid in measuring prion species barriers, thereby reducing animal use and providing quicker results than animal bioassays. Here, we present the protocol for a rapid in vitro prion conversion assay called the conversion efficiency ratio (CER) assay. In this assay cellular prion protein (PrPC) from an uninfected host brain is denatured at both pH 7.4 and 3.5 to produce two substrates. When the pH 7.4 substrate is incubated with TSE agent, the amount of PrPC that converts to a proteinase K (PK)-resistant state is modulated by the original host&#8217;s species barrier to the TSE agent. In contrast, PrPC in the pH 3.5 substrate is misfolded by any TSE agent. By comparing the amount of PK-resistant prion protein in the two substrates, an assessment of the host&#8217;s species barrier can be made. We show that the CER assay correctly predicts known prion species barriers of laboratory mice and, as an example, show some preliminary results suggesting that bobcats (Lynx rufus) may be susceptible to white-tailed deer (Odocoileus virginianus) chronic wasting disease agent.

Assessing Transmissible Spongiform Encephalopathy Species Barriers with an In Vitro Prion Protein Conversion Assay

Measuring the barrier to the interspecies transmission of prion diseases is challenging and typically involves animal challenges or biochemical assays. Here, we present an in vitro prion protein conversion assay with the ability to predict species barriers.

Studies to understanding interspecies transmission of transmissible spongiform encephalopathies (TSEs, prion diseases) are challenging in that they ...

Assessing Specificity of Anticancer Drugs In Vitro

A procedure for assessing specificity of anticancer drugs in vitro using cultures containing both tumor and non-tumor cells is demonstrated. The key element is the quantitative determination of a tumor-specific genetic alteration in relation to a universal sequence using a dual-probe digital PCR assay and the subsequent calculation of the proportion of tumor cells. The assay is carried out on a culture containing tumor cells of an established line and spiked-in non-tumor cells. The mixed culture is treated with a test drug at various concentrations. After the treatment, DNA is prepared directly from the survived adhesive cells in wells of 96-well plates using a simple and inexpensive method, and subjected to a dual-probe digital PCR assay for measuring a tumor-specific genetic alteration and a reference universal sequence. In the present demonstration, a heterozygous deletion of the NF1 gene is used as the tumor-specific genetic alteration and a RPP30 gene as the reference gene. Using the ratio NF1/RPP30, the proportion of tumor cells was calculated. Since the dose-dependent change of the proportion of tumor cells provides an in vitro indication for specificity of the drug, this genetic and cell-based in vitro assay will likely have application potential in drug discovery. Furthermore, for personalized cancer-care, this genetic- and cell-based tool may contribute to optimizing adjuvant chemotherapy by means of testing efficacy and specificity of candidate drugs using primary cultures of individual tumors.

Assessing Specificity of Anticancer Drugs In Vitro

The goal of this protocol is to assess specificity of anticancer drugs in vitro using mixed cultures containing both tumor and non-tumor cells.

A procedure for assessing specificity of anticancer drugs in vitro using cultures containing both tumor and non-tumor cells is demonstrated. The key ...

Optimized LC-MS/MS Method for the High-throughput Analysis of Clinical Samples of Ivacaftor, Its Major Metabolites, and Lumacaftor in Biological Fluids of Cystic Fibrosis Patients

Defects in the cystic fibrosis trans-membrane conductance regulator (CFTR) are the cause of cystic fibrosis (CF), a disease with life-threatening pulmonary manifestations. Ivacaftor (IVA) and ivacaftor-lumacaftor (LUMA) combination are two new breakthrough CF drugs that directly modulate the activity and trafficking of the defective CFTR-protein. However, there is still a dearth of understanding on pharmacokinetic/pharmacodynamic parameters and the pharmacology of ivacaftor and lumacaftor. The HPLC-MS technique for the simultaneous analysis of the concentrations of ivacaftor, hydroxymethyl-ivacaftor, ivacaftor-carboxylate, and lumacaftor in biological fluids in patients receiving standard ivacaftor or ivacaftor-lumacaftor combination therapy has previously been developed by our group and partially validated to FDA standards. However, to allow the high-throughput analysis of a larger number of patient samples, our group has optimized the reported method through the use of a smaller pore size reverse-phase chromatography column (2.6 &#181;m, C8 100 &#197;; 50 x 2.1 mm) and a gradient solvent system (0-1 min: 40% B; 1-2 min: 40-70% B; 2-2.7 min: held at 70% B; 2.7-2.8 min: 70-90% B; 2.8-4.0 min: 90% B washing; 4.0-4.1 min: 90-40% B; 4.1-6.0 min: held at 40% B) instead of an isocratic elution. The goal of this study was to reduce the HPLC-MS analysis time per sample dramatically from ~15 min to only 6 min per sample, which is essential for the analysis of a large amount of patient samples. This expedient method will be of considerable utility for studies into the exposure-response relationships of these breakthrough CF drugs.

Ivacaftor and ivacaftor-lumacaftor combination are two new CF drugs. However, there is still a dearth of understanding on their PK/PD and pharmacology. We present an optimized HPLC-MS technique for the simultaneous analysis of ivacaftor and its major metabolites, and lumacaftor.

Defects in the cystic fibrosis trans-membrane conductance regulator (CFTR) are the cause of cystic fibrosis (CF), a disease with life-threatening ...

Improved Method for the Establishment of an In Vitro Blood-Brain Barrier Model Based on Porcine Brain Endothelial Cells

The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) models based on pBECs in mono-culture (MC), MC with astrocyte-conditioned medium (ACM), and non-contact co-culture (NCC) with astrocytes of porcine or rat origin. pBECs were isolated and cultured from fragments of capillaries from the brain cortices of domestic pigs 5-6 months old. These fragments were purified by careful removal of meninges, isolation and homogenization of grey matter, filtration, enzymatic digestion, and centrifugation. To further eliminate contaminating cells, the capillary fragments were cultured with puromycin-containing medium. When 60-95% confluent, pBECs growing from the capillary fragments were passaged to permeable membrane filter inserts and established in the models. To increase barrier tightness and BBB characteristic phenotype of pBECs, the cells were treated with the following differentiation factors: membrane permeant 8-CPT-cAMP (here abbreviated cAMP), hydrocortisone, and a phosphodiesterase inhibitor, RO-20-1724 (RO). The procedure was carried out over a period of 9-11 days, and when establishing the NCC model, the astrocytes were cultured 2-8 weeks in advance. Adherence to the described procedures in the protocol has allowed the establishment of endothelial layers with highly restricted paracellular permeability, with the NCC model showing an average transendothelial electrical resistance (TEER) of 1249 &#177; 80 &#937; cm2, and paracellular permeability (Papp) for Lucifer Yellow of 0.90 10-6 &#177; 0.13 10-6 cm sec-1 (mean &#177; SEM, n=55). Further evaluation of this pBEC phenotype showed good expression of the tight junctional proteins claudin 5, ZO-1, occludin and adherens junction protein p120 catenin. The model presented can be used for a range of studies of the BBB in health and disease and, with the highly restrictive paracellular permeability, this model is suitable for studies of transport and intracellular trafficking.

Improved Method for the Establishment of an In Vitro Blood-Brain Barrier Model Based on Porcine Brain Endothelial Cells

The aim of the protocol is to present an optimized procedure for the establishment of an in vitro blood-brain barrier (BBB) model based on primary porcine brain endothelial cells (pBECs). The model shows high reproducibility, high tightness, and is suitable for studies of transport and intracellular trafficking in drug discovery.

The aim of this protocol presents an optimized procedure for the purification and cultivation of pBECs and to establish in vitro blood-brain barrier (BBB) ...

A Fluorescence-based Assay for Characterization and Quantification of Lipid Droplet Formation in Human Intestinal Organoids

Dietary lipids are taken up as free fatty acids (FAs) by the intestinal epithelium. These FAs are intracellularly converted into triglyceride (TG) molecules, before they are packaged into chylomicrons for transport to the lymph or into cytosolic lipid droplets (LDs) for intracellular storage. A crucial step for the formation of LDs is the catalytic activity of diacylglycerol acyltransferases (DGAT) in the final step of TG synthesis. LDs are important to buffer toxic lipid species and regulate cellular metabolism in different cell types. Since the human intestinal epithelium is regularly confronted with high concentrations of lipids, LD formation is of great importance to regulate homeostasis. Here we describe a simple assay for the characterization and quantification of LD formation (LDF) upon stimulation with the most common unsaturated fatty acid, oleic acid, in human intestinal organoids. The LDF assay is based on the LD-specific fluorescent dye LD540, which allows for quantification of LDs by confocal microscopy, fluorescent plate reader, or flow cytometry. The LDF assay can be used to characterize LD formation in human intestinal epithelial cells, or to study human (genetic) disorders that affect LD metabolism, such as DGAT1 deficiency. Furthermore, this assay can also be used in a high-throughput pipeline to test novel therapeutic compounds, which restore defects in LD formation in intestinal or other types of organoids.

This protocol describes an assay for the characterization of lipid droplet (LD) formation in human intestinal organoids upon stimulation with fatty acids. We discuss how this assay is used for quantification of LD formation, and how it can be used for high throughput screening for drugs that affect LD formation.

Dietary lipids are taken up as free fatty acids (FAs) by the intestinal epithelium. These FAs are intracellularly converted into triglyceride (TG) ...

Investigating Intestinal Barrier Breakdown in Living Organoids

Organoids and three-dimensional (3D) cell cultures allow the investigation of complex biological mechanisms and regulations in vitro, which previously was not possible in classical cell culture monolayers. Moreover, monolayer cell cultures are good in vitro model systems but do not represent the complex cellular differentiation processes and functions that rely on 3D structure. This has so far only been possible in animal experiments, which are laborious, time consuming, and hard to assess by optical techniques. Here we describe an assay to quantitatively determine the barrier integrity over time in living small intestinal mouse organoids. To validate our model, we applied interferon gamma (IFN-&#947;) as a positive control for barrier destruction and organoids derived from IFN-&#947; receptor 2 knock out mice as a negative control. The assay allowed us to determine the impact of IFN-&#947; on the intestinal barrier integrity and the IFN-&#947; induced degradation of the tight junction proteins claudin-2, -7, and -15. This assay could also be used to investigate the impact of chemical compounds, proteins, toxins, bacteria, or patient-derived probes on the intestinal barrier integrity.

Here we describe a technique to quantify the barrier integrity of small intestinal organoids. The fact that the method is based on living organoids enables the sequential investigation of different barrier integrity modulating substances or combinations thereof in a time-resolved manner.

Organoids and three-dimensional (3D) cell cultures allow the investigation of complex biological mechanisms and regulations in vitro, which previously was ...

Using a Chemical Biopsy for Graft Quality Assessment

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated with an increased survival rate and greater quality of patient&#8217;s life when compared to conventional dialysis. Regrettably, transplantology suffers from a lack of reliable methods for organ quality assessment. Standard diagnostic techniques are limited to macroscopic appearance inspection or invasive tissue biopsy, which do not provide comprehensive information about the graft. The proposed protocol aims to introduce solid phase microextraction (SPME) as an ideal analytical method for comprehensive metabolomics and lipidomic analysis of all low molecular compounds present in kidneys allocated for transplantation. The small size of the SPME probe enables performance of a chemical biopsy, which enables extraction of metabolites directly from the organ without any tissue collection. The minimum invasiveness of the method permits execution of multiple analyses over time: directly after organ harvesting, during its preservation, and immediately after revascularization at the recipient&#8217;s body. It is hypothesized that the combination of this novel sampling method with a high-resolution mass spectrometer will allow for discrimination of a set of characteristic compounds that could serve as biological markers of graft quality and indicators of possible development of organ dysfunction.

The protocol presents utilization of the chemical biopsy approach followed by comprehensive metabolomic and lipidomic analysis for quality assessment of kidney grafts allocated for transplantation.

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated ...

Culture and Imaging of Human Nasal Epithelial Organoids

Individualized therapy for cystic fibrosis (CF) patients can be achieved with an in vitro disease model to understand baseline Cystic Fibrosis Transmembrane conductance Regulator (CFTR) activity and restoration from small molecule compounds. Our group recently focused on establishing a well-differentiated organoid model directly derived from primary human nasal epithelial cells (HNE). Histology of sectioned organoids, whole-mount immunofluorescent staining, and imaging (using confocal microscopy, immunofluorescent microscopy, and bright field) are essential to characterize organoids and confirm epithelial differentiation in preparation for functional assays. Furthermore, HNE organoids produce lumens of varying sizes that correlate with CFTR activity, distinguishing between CF and non-CF organoids. In this manuscript, the methodology for culturing HNE organoids are described in detail, focusing on the assessment of differentiation using the imaging modalities, including the measurement of baseline lumen area (a method of CFTR activity measurement in organoids that any laboratory with a microscope can employ) as well as the developed automated approach to a functional assay (which requires more specialized equipment).

A detailed protocol is presented here to describe an in vitro organoid model from human nasal epithelial cells. The protocol has options for measurements requiring standard laboratory equipment, with additional possibilities for specialized equipment and software.

Individualized therapy for cystic fibrosis (CF) patients can be achieved with an in vitro disease model to understand baseline Cystic Fibrosis ...

Rectal Organoid Morphology Analysis (ROMA): A Diagnostic Assay in Cystic Fibrosis

Diagnosis of cystic fibrosis (CF) is not always straightforward, especially when sweat chloride concentration is intermediate and/or less than two disease-causing CFTR mutations can be identified. Physiological CFTR assays (nasal potential difference, intestinal current measurement) have been included in the diagnostic algorithm but are not always readily available or feasible (e.g., in infants). Rectal organoids are 3D structures that grow from stem cells isolated from crypts of a rectal biopsy when cultured under specific conditions. Organoids from non-CF subjects have a round shape and a fluid-filled lumen, as CFTR-mediated chloride transport drives water into the lumen. Organoids with defective CFTR function do not swell, retaining an irregular shape and having no visible lumen. Differences in morphology between CF and non-CF organoids are quantified in the &#39;Rectal Organoid Morphology Analysis&#39; (ROMA) as a novel CFTR physiological assay. For the ROMA assay, organoids are plated in 96-well plates, stained with calcein, and imaged in a confocal microscope. Morphological differences are quantified using two indexes: The circularity index (CI) quantifies the roundness of organoids, and the intensity ratio (IR) is a measure of the presence of a central lumen. Non-CF organoids have a high CI and low IR compared to CF organoids. ROMA indexes perfectly discriminated 167 subjects with CF from 22 subjects without CF, making ROMA an appealing physiological CFTR assay to aid in CF diagnosis. Rectal biopsies can be routinely performed at all ages in most hospitals and tissue can be sent to a central lab for organoid culture and ROMA. In the future, ROMA might also be applied to test the efficacy of CFTR modulators in vitro. The aim of the present report is to fully explain the methods used for ROMA, to allow replication in other labs.

Rectal Organoid Morphology Analysis ROMA: A Diagnostic Assay in Cystic Fibrosis

This protocol describes rectal organoid morphology analysis (ROMA), a novel diagnostic assay for cystic fibrosis (CF). Morphological characteristics, namely the roundness (circularity index, CI) and the presence of a lumen (intensity ratio, IR), are a measure of CFTR function. Analysis of 189 subjects showed perfect discrimination between CF and non-CF.