Isolation and Enrichment of Human Lung Epithelial Progenitor Cells for Organoid Culture
Summary
This article provides a detailed methodology for tissue dissociation and cellular fractionation approaches allowing enrichment of viable epithelial cells from proximal and distal regions of the human lung. Herein these approaches are applied for the functional analysis of lung epithelial progenitor cells through the use of 3D organoids culture models.
Abstract
Epithelial organoid models serve as valuable tools to study the basic biology of an organ system and for disease modeling. When grown as organoids, epithelial progenitor cells can self-renew and generate differentiating progeny that exhibit cellular functions similar to those of their in vivo counterparts. Herein we describe a step-by-step protocol to isolate region-specific progenitors from human lung and generate 3D organoid cultures as an experimental and validation tool. We define proximal and distal regions of the lung with the goal of isolating region-specific progenitor cells. We utilized a combination of enzymatic and mechanical dissociation to isolate total cells from the lung and trachea. Specific progenitor cells were then fractionated from the proximal or distal origin cells using fluorescence associated cell sorting (FACS) based on cell type-specific surface markers, such as NGFR for sorting basal cells and HTII-280 for sorting alveolar type II cells. Isolated basal or alveolar type II progenitors were used to generate 3D organoid cultures. Both distal and proximal progenitors formed organoids with a colony forming efficiency of 9-13% in distal region and 7-10% in proximal region when plated 5000 cell/well on day 30. Distal organoids maintained HTII-280+ alveolar type II cells in culture whereas proximal organoids differentiated into ciliated and secretory cells by day 30. These 3D organoid cultures can be used as an experimental tool for studying the cell biology of lung epithelium and epithelial mesenchymal interactions, as well as for the development and validation of therapeutic strategies targeting epithelial dysfunction in a disease.
Introduction
Airspaces of the human respiratory system can be broadly divided into conducting and respiratory zones that mediate transport of gasses and their subsequent exchange across the epithelial-microvascular barrier, respectively. The conducting airways include trachea, bronchi, bronchioles and terminal bronchioles, whereas respiratory air spaces include respiratory bronchioles, alveolar ducts and alveoli. The epithelial lining of these airspaces changes in composition along the proximo-distal axis to accommodate the unique requirements of each functionally distinct zone. The pseudostratified epithelium of tracheo-bronchial airways is composed of three major cell types, basal, secretory and ciliated, in addition to the less abundant cell types including brush, neuroendocrine and ionocyte1,2,3. Bronchiolar airways harbor morphologically similar epithelial cell types, although there are distinctions in their abundance and functional properties. For example, basal cells are less abundant within bronchiolar airways, and secretory cells include a greater proportion of club cells versus serous and goblet cells that predominate in tracheo-bronchial airways. Epithelial cells of the respiratory zone include a poorly defined cuboidal cell type in respiratory bronchioles, in addition to alveolar type I (ATI) and type II (ATII) cells of alveolar ducts and alveoli1,4.
The identity of epithelial stem and progenitor cell types that contribute to the maintenance and renewal of epithelia in each zone are incompletely described and largely inferred from studies in animal models5,6,7,8. Studies in mice have shown that either basal cells of pseudostratified airways, or club cells of bronchiolar airways or ATII cells of the alveolar epithelium, serve as epithelial stem cells based upon capacity for unlimited self-renewal and multipotent differentiation7,9,10,11,12. Despite the inability to perform genetic lineage tracing studies to assess stemness of human lung epithelial cell types, the availability of organoid-based culture models to assess the functional potential of epithelial stem and progenitor cells provide a tool for comparative studies between mouse and human13,14,15,16,17.
We describe methods for the isolation of epithelial cell types from different regions of the human lung and their culture using a 3D organoid system to recapitulate the regional cell types. Similar methods have been developed for the functional analysis and disease modeling of epithelial cells from other organ systems18,19,20,21. These methods provide a platform for the identification of regional epithelial progenitor cells, to perform mechanistic studies investigating their regulation and microenvironment, and to enable disease modeling and drug discovery. Even though studies of lung epithelial progenitor cells performed in animal models can benefit from the analysis, either in vivo or in vitro, insights into the identity of human lung epithelial progenitor cells have been largely dependent upon extrapolation from model organisms. As such, these methods provide a bridge to relate the identity and behavior of human lung epithelial cell types with their studies investigating regulation of stem/progenitor cells.
Protocol
Representative Results
Discussion
We describe a reliable method for the isolation of defined subpopulations of lung cells from human lung tissue for either molecular or functional analysis and disease modeling. Critical elements of methods include the ability to achieve tissue dissociation with preservation of surface epitopes, which allow antibody-mediated enrichment of freshly isolated cells, and the optimization of culture methods for the efficient generation of region-specific epithelial organoids. We focus on the recovery and enrichment of epithelia…
Disclosures
The authors have nothing to disclose.
Acknowledgements
We appreciate support from Mizuno Takako for IFC and H and E staining, Vanessa Garcia for tissue sectioning and Anika S Chandrasekaran for helping with manuscript preparation. This work is supported by National Institutes of Health (5RO1HL135163-04, PO1HL108793-08) and Celgene IDEAL Consortium.
Materials
| Cell Isolation | |||
| 10 mL Sterile syringes, Luer-Lok Tip | Fisher scientific | BD 309646 | |
| 30 mL Sterile syringes, Luer-Lok Tip | VWR | BD302832 | |
| Biohazard bags | VWR | 89495-440 | |
| Biohazard bags | VWR | 89495-440 | |
| connecting ring | Pluriselect | 41-50000-03 | |
| Deoxyribonuclease (lot#SLBF7798V) | sigma Aldrich | DN25-1G | |
| Disposable Petri dishes | Corning/Falcon | 25373-187 | |
| Funnel | Pluriselect | 42-50000 | |
| HBSS | Corning | 21-023 | |
| Liberase TM Research Grade | sigma Aldrich | 5401127001 | |
| needle 16G | VWR | 305198 | |
| needle 18G | VWR | 305199 | |
| PluriStrainer 100 µm (Cell Strainer) | Pluriselect | 43-50100-51 | |
| PluriStrainer 300 µm (Cell Strainer) | Pluriselect | 43-50300-03 | |
| PluriStrainer 40 µm (Cell Strainer) | Pluriselect | 43-50040-51 | |
| PluriStrainer 500 µm (Cell Strainer) | Pluriselect | 43-50500-03 | |
| PluriStrainer 70 µm (Cell Strainer) | Pluriselect | 43-50070-51 | |
| Razor blades | VWR | 55411-050 | |
| Red Blood Cell lysis buffer | eBioscience | 00-4333-57 | |
| Equipment’s | |||
| GentleMACS C Tubes | MACS Miltenyi Biotec | 130-096-334 | |
| GentleMACS Octo Dissociator | MACS Miltenyi Biotec | 130-095-937 | |
| Leica ASP 300s Tissue processor | |||
| LS Columns | MACS Miltenyi Biotec | 130-042-401 | |
| MACS MultiStand** | Miltenyi Biotech | 130-042-303 | |
| Thermomixer | Eppendorf | 05-412-503 | |
| Thermomixer | Eppendorf | 05-412-503 | |
| HBSS+ Buffer | |||
| Amphotericin B | Thermo fisher scientific | 15290018 | 2ml |
| EDTA (0.5 M), pH 8.0, RNase-free | Thermo fisher scientific | AM9260G | 500µl |
| Fetal Bovine Serum | Gemini Bio-Products | 100-106 | 10ml |
| HBSS Hank's Balanced Salt Solution 1X 500 ml | VWR | 45000-456 | 500ml bottle |
| HEPES (1 M) | Thermo fisher scientific | 15630080 | 5ml |
| Penicillin-Streptomycin-Neomycin (PSN) Antibiotic Mixture | Thermo fisher scientific | 15640055 | 5ml |
| List of antibodies for FACS | |||
| Alexa Fluor 647 anti-human CD326 (EpCAM) Antibody | BioLegend | 369820 | 1:50 |
| BD CompBead Anti-Mouse Ig, K/ Negative control particles set | Fisher Scientific | BDB552843 | |
| CD31 MicroBead Kit, human | Miltenyi Biotec | 130-091-935 | 20µl/ 107 total cells |
| CD45 MicroBeads, human | Miltenyi Biotec | 130-045-801 | 20µl/ 107 total cells |
| DAPI | Sigma Aldrich | D9542-10MG | 1:10000 |
| FITC anti-human CD235a | BioLegend | 349104 | 1:100 |
| FITC anti-human CD31 | BioLegend | 303104 | 1:100 |
| FITC anti-human CD45 | BioLegend | 304054 | 1:100 |
| FITC anti-mouse IgM Antibody | BioLegend | 406506 | 1:500 |
| Mouse IgM anti human HT2-280 | Terrace Biotech | TB-27AHT2-280 | 1:300 |
| PE anti-human CD271(NGFR) | BioLegend | 345106 | 1:50 |
| Composition of Organoid Culture mediums | |||
| MRC-5 | ATCC | CCL-171 | |
| PneumaCult -ALI Medium | Stemcell Technologies | 5001 | |
| Small Airway Epithelial Cell Growth Medium | PromoCell | C-21170 | |
| ThinCert Tissue Culture Inserts, Sterile | Greiner Bio-One | 662641 | |
| Y-27632 (ROCK inhibitor) 100mM stock (1000x) | Stemcell Technologies | 72302 | |
| Mouse Basal medium: | |||
| Amphotericin B | Thermo fisher scientific | 15290018 | 50 µl |
| DMEM/F-12, HEPES | ThermoFisher scientific | 11330032 | 50 ml |
| Fetal Bovine Serum | Gemini Bio-Products | 100-106 | 5 ml |
| Insulin-Transferrin-Selenium (ITS -G) (100X) | ThermoFisher scientific | 41400045 | 500 µl |
| Penicillin-Streptomycin-Neomycin (PSN) Antibiotic Mixture | Thermo fisher scientific | 15640055 | 500 µl |
| SB431542 TGF-β pathway inhibitor (stock 100 mM) | Stem cell | 72234 | 5 µl |
| List of antibodies for Immunohistochemistry | |||
| Antigen unmasking solution, citric acid based | Vector | H-3300 | 937 µl in 100ml water |
| Histogel | Thermo Scientific | HG-4000-012 | |
| Primary Antibodies | |||
| Anti HT2-280 | Terracebiotech | TB-27AHT2-280 | 1:500 |
| FOXJ1 Monoclonal Antibody (2A5) | Thermo Fisher Scientific | 14-9965-82 | 1:300 |
| Human Uteroglobin/SCGB1A1 Antibody | R and D systems | MAB4218 | 1:300 |
| Keratin 5 Polyclonal Chicken Antibody, Purified [Poly9059] | Biolegend | 905901 | 1:500 |
| MUC5AC Monoclonal Antibody (45M1) | Thermo Fisher Scientific | MA5-12178 | 1:300 |
| PDPN / Podoplanin Antibody (clone 8.1.1) | LifeSpan Biosciences | LS-C143022-100 | 1:300 |
| Purified Mouse Anti-E-Cadherin | BD biosciences | 610182 | 1:1000 |
| Sox-2 Antibody | Santa Cruz biotechnologies | sc-365964 | 1:300 |
| Secondary Antibodies | |||
| Donkey anti-rabbit lgG, 488 | Thermo Fisher Scientific | A-21206 | 1:500 |
| FITC anti-mouse IgM Antibody | BioLegend | 406506 | 1:500 |
| Goat anti-Hamster IgG (H+L), Alexa Fluor 594 | Thermo Fisher Scientific | A-21113 | 1:500 |
| Goat anti-Mouse IgG1 Cross-Adsorbed Secondary Antibody, Alexa Fluor 488 | Thermo Fisher Scientific | A-21121 | 1:500 |
| Goat anti-Mouse IgG2a Cross-Adsorbed Secondary Antibody, Alexa Fluor 488 | Thermo Fisher Scientific | A-21131 | 1:500 |
| Goat anti-Mouse IgG2a Cross-Adsorbed Secondary Antibody, Alexa Fluor 568 | Thermo Fisher Scientific | A-21134 | 1:500 |
| Goat anti-Mouse IgG2b Cross-Adsorbed Secondary Antibody, Alexa Fluor 568 | Thermo Fisher Scientific | A-21144 | 1:500 |
| Buffers | |||
| Immunohistochemistry Blocking Solution | 3% BSA, o.4% Triton-x100 in TBS (Tris based saline) | ||
| Immunohistochemistry Incubation Solution | 3% BSA, ).1% Triton-X100 in TBS | ||
| Immunohistochemistry Washing Solution | TBS with 0.1% Tween 20 | ||
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