Here we present protocols that enable isolation of stromal cells from murine bone, bone marrow, thymus and human thymic tissue compatible with single-cell multiomics.
Single-cell sequencing has enabled the mapping of heterogeneous cell populations in the stroma of hematopoietic organs. These methodologies provide a lens through which to study previously unresolved heterogeneity at steady state, as well as changes in cell type representation induced by extrinsic stresses or during aging. Here, we present step-wise protocols for the isolation of high-quality stromal cell populations from murine and human thymus, as well as murine bone and bone marrow. Cells isolated through these protocols are suitable for generating high-quality single-cell multiomics datasets. The impacts of sample digestion, hematopoietic lineage depletion, FACS analysis/sorting, and how these factors influence compatibility with single-cell sequencing are discussed here. With examples of FACS profiles indicating successful and inefficient dissociation and downstream stromal cell yields in post-sequencing analysis, recognizable pointers for users are provided. Considering the specific requirements of stromal cells is crucial for acquiring high-quality and reproducible results that can advance knowledge in the field.
In the healthy adult, de novo production of blood cells occurs in the bone marrow and the thymus. Stromal cells at these sites are essential for maintenance of hematopoiesis, but stroma constitutes less than 1% of the tissue1,2,3,4. Obtaining pure isolates of hematopoiesis supporting stroma therefore constitutes a significant challenge, particularly for single-cell multiomics that requires expedient processing to obtain samples of high quality. Components of different digestion cocktails may interfere with certain steps in multiomics analysis5,6. The protocols presented here detail the isolation of a wide variety of stromal cells from bone marrow and thymic tissues.
Perturbations of stromal constituents in both bone marrow and thymus result in profound disruption in blood cell development and can result in malignancies7,8,9. Hematopoiesis supporting stroma is damaged following cytotoxic conditioning and bone marrow transplantation, resulting in reduced secretion of cytokines and growth factors that sustain hematopoietic stem and progenitor cells (HSPCs)2,10,11. Furthermore, aging affects bone marrow and thymus stromal cells likely contributing to aged hematopoietic phenotypes. The thymus is the first organ to undergo extensive age-associated involution. Fat and fibrotic tissue start replacing T cell supportive stroma as early as the onset of puberty12,13. In the bone marrow, adipocyte content increases with age and the vascular and endosteal niches are significantly remodeled14,15,16.
To enable study of hematopoiesis supportive stroma across multiple stress states and in the case of the thymus of both human and murine tissue, we have optimized previously published digestion protocols1,2,8,17,18. These protocols ensure efficient and reproducible isolation of cells, and they are compatible with single-cell RNAsequencing (scRNAseq) and other types of multiomics.
Stromal cells in hematopoietic organs are critical for normal blood production and hematopoietic stroma perturbations can result in severe impairments in hematopoietic maintenance and response to stress9,23,24. Insight into hematopoietic stromal cells is essential for understanding hematological diseases7,9,10,<sup class="xre…
The authors have nothing to disclose.
We were supported with expert technical assistance by the HSCI-CRM Flow Cytometry facility at Massachusetts General Hospital and the Bauer Core Facility at Harvard University. T.K and K. G were supported by the Swedish Research Council and C.M. by the German Research Foundation. We thank Sergey Isaev and I-Hsiu Lee for assistance in analysis of single-cell RNA sequencing data.
0.25% Trypsin-EDTA | Thermo Fisher Scientific | 25200-072 | |
7AAD (7-aminoactinomycin D) | BD Biosciences | 559925 | |
Anti-Human Lineage Cocktail 3-FITC | BD Biosciences | 643510 | |
Bovine Serum Albumin | Millipore Sigma | A9647 | |
C57Bl/6 mice | Jackson | 664 | Males or females, 8-12 weeks old |
Calcein | Fisher Scientific | 65-0853-78 | |
Collagenase IV | Millipore Sigma | C5138 | |
Corning Sterile Cell Strainers, White, Mesh Size: 70 µm | Fisher Scientific | 08-771-2 | |
DAPI (4',6-Diamidino-2-Phenylindole, Dilactate) | Biolegend | 422801 | |
Dispase II | Thermo Fisher Scientific | 17105041 | |
Dnase I Solution | Thermo Fisher Scientific | 90083 | 2500 U/mL |
Easysep mouse streptavidin RapidSpheres Isolation kit | StemCell Technologies | 19860 | |
Fetal Bovine Serum | Gibco | A31605-01 | Qualified One Shot |
Human Fc Block | BD Biosciences | 564220 | |
Liberase TM | Millipore Sigma | 5401127001 | Research Grade |
Medium 199 | Gibco | 12350 | |
Mouse anti-human CD235a-BV77 | BD Biosciences | 740785 | |
Mouse anti-human CD31-PE/Dazzle594 | Biolegend | 303130 | |
Mouse anti-human CD45-BV77 | Biolegend | 304050 | |
Mouse anti-human CD4-BV605 | BD Biosciences | 562658 | |
Mouse anti-human CD66b-FITC | BD Biosciences | 555724 | |
Mouse anti-human CD8-APC/Cy7 | BD Biosciences | 557760 | |
Mouse anti-human EpCam-BV421 | Biolegend | 324220 | |
Protector RNase Inhibitor | Millipore Sigma | 3335402001 | |
Rat anti-mouse CD105-PE /dazzle594 | Biolegend | 120424 | |
Rat anti-mouse CD11b-Biotin | Biolegend | 101204 | |
Rat anti-mouse CD140a-APC | Fisher Scientific | 17-1401-81 | |
Rat Anti-Mouse CD16/CD32 (Mouse BD Fc Block) | BD Biosciences | 553142 | |
Rat anti-mouse CD31-BUV737 | BD Biosciences | 612802 | |
Rat anti-mouse CD31-BV421 | Biolegend | 102424 | |
Rat anti-mouse CD3-Biotin | Biolegend | 100244 | |
Rat anti-mouse CD45.2-Biotin | Biolegend | 109804 | |
Rat anti-mouse CD45-PE/Cy7 | Biolegend | 103114 | |
Rat anti-mouse CD45-PE/Cy7 | Biolegend | 103114 | |
Rat anti-mouse CD45R/B220-Biotin | Biolegend | 103204 | |
Rat anti-mouse CD51-PE | Biolegend | 104106 | |
Rat anti-mouse EpCam-BV711 | BD Biosciences | 563134 | |
Rat anti-mouse Ly-6A/E(Sca-1)-AF700 | Biolegend | 108142 | |
Rat anti-mouse Ly-6G/Ly-6C(Gr1)-Biotin | Biolegend | 108404 | |
Rat anti-mouse Ter119-Biotin | Biolegend | 116204 | |
Rat anti-mouse Ter119-PE | Biolegend | 116208 | |
Rat anti-mouse Ter119-PE/Cy7 | Biolegend | 116222 | |
Stemxyme | Worthington Biochemical | LS004107 |
.