Harvesting Bone Marrow From Femurs and Tibiae
<ol>
<li>The first step of the procedure is to harvest bone marrow from the femurs and tibiae of a 6- to 12-week old mouse (we are using BALB/c mice but you can do this procedure with any mouse strain). To begin, euthanize the mouse by CO2 inhalation (won&rsquo;t be shown). Harvest femur and tibiae from the hind legs of each. Then, with a razor blade, cut each end of the femurs to remove the hip and knee joints and to expose the marrow.</li>
<li>In a similar manner, cut each end of the tibiae to remove the knee and ankle adjacent regions and to expose the marrow.</li>
<li>Take a 3 mL syringe with a 26-gauge needle and fill it with RPMI supplemented with 10% FBS, penicillin, streptomycin, and beta-mercaptoethanol (BME = 100 uM). Using tweezers, hold the bone over a Petri dish containing RPMI media. Insert the syringe needle into one end of the bone and depress the plunger to flush out the bone marrow. The syringe needle can be moved up and down inside the bone to flush out residual marrow.</li>
<li>Repeat the procedure for all the bones, and then proceed with establishing the cultures.</li>
</ol>
Establishing Cultures
<ol>
<li> To establish the bone marrow cultures, pipette the flushed bone marrow up and down several times to break up the tissue into a cell suspension.</li>
<li>Place a 70 micron filter on top of a 50 mL conical tube, and add the cell suspension to the filter.</li>
<li>Rinse the Petri dish one time with RPMI, then add the rinse to the 70 micron filter.</li>
<li>Using the rubber end of a 1 mL syringe plunger, grind the bone marrow pieces remaining on top of the 70 micron filter.</li>
<li>Wash the filter one time with RPMI.</li>
<li>After washing the filter, centrifuge the cell suspension at 1200 rpm for 5 minutes.</li>
<li>Wash the cell pellet by resuspending in PBS.</li>
<li>Count the cells using a hemocytometer. We typically obtain ~90 million cells from one mouse&rsquo;s bones (two femurs plus two tibiae). After counting the cells, centrifuge them again at 1200 rpm for 5 minutes.</li>
<li>Resuspend the cells in a small amount of RPMI and aliquot them into tissue culture flasks containing enough RPMI so that the final concentration is 1 million cells per mL.</li>
<li>Add cytokines to promote the development of your cell type of interest. In this case, the cytokine interleukin-3 (IL-3 = 10 ng/mL) is added to promote the development of basophils and mast cells. To acquire basophils, incubate for 10 days. For mast cells, incubate for 5 weeks. When generating mast cells, the media and IL-3 should be changed once a week.</li>
<li>Here is a look at how mast cells should appear just after plating. This image demonstrates the differentiation of mast marrow cells into basophils and mast cells 10 days after the addition of interleukin-3.</li>
<li>Once the desired cell type is obtained, proceed with the electroporation step.</li>
</ol>
&nbsp;
Electroporating Cells
<ol>
<li>To begin the electroporation step, determine the number of cells in the culture flask.</li>
<li>Cells are typically electroporated at a density of 10 million per mL, so transfer the required cell number to conical tubes and centrifuge the tubes at 1200 rpm for 5 minutes.</li>
<li>After centrifuging, aspirate the media, wash the cells with 1X PBS, and centrifuge again at 1200 rpm for 5 minutes.</li>
<li>Aspirate the PBS and add Bio-Rad Gene Pulser electroporation buffer to make a cell suspension of 10 million cells per mL.</li>
<li>After resuspending the cells, add the desired plasmid DNA at a final concentration of 10 to 20 micrograms per mL.</li>
<li>Aliquot 150 microliters of the cell suspension into wells of your choice on a 96-well electroporation plate.</li>
<li>Put the electroporation plate in the MXcell plate chamber and close the lid.</li>
<li>Prior to transfection of mast cells, an electroporation protocol must be programmed into the MXcell unless using a preset or stored protocol. Through optimization experiments we have discovered that the highest transfection efficiencies of mast cells occur using square wave pulse protocols. We will vary the electroporation conditions on the plate to deliver 300V/20ms, 350/15ms, 350V/20ms, and 350V/10ms square wave pulses at 2000uF and 1000 ohms. Once the protocol has been set and loaded onto the device, press &ldquo;Pulse&rdquo; to electroporate the cells.</li>
<li>After electroporation is complete, transfer the cells to a tissue culture plate. We typically transfer each 150 microliter electroporation sample to a well in a 48-well tissue culture plate containing 300 microliters RPMI (supplemented with 10% FCS, penicillin, streptomycin, and beta-mercaptoethanol) with 10 nanograms per mL interleukin-3. Cells are incubated overnight at 37&deg;C, then assayed 24 hours later for expression and suppression.</li>
</ol>
Transfection Results
The fluorescent microscopy image of the cells after successful electroporation using 20 micrograms per mL GFP plasmid is shown in the video. Using the MXcell electroporation system transfection efficiencies of about 30% can be obtained. The system allows you to vary conditions to maximize your transfection efficiency, while maintaining cell viability.

As more genomic information emerges and new tools such as siRNA are developed, the use of physiologically relevant cells has become ever more important to further our understanding of disease pathways, protein-protein interactions, and signal transduction. Primary cells are obtained directly from tissues or fluids and cultivated in vitro. These cells can be manipulated in a number of ways, including through the introduction of exogenous genetic material. It is becoming increasingly apparent that the most effective way to introduce plasmid DNA or siRNA into primary cells is electroporation.
Electroporation exposes cells to electric pulses in order to transiently increase the permeability of the cell membrane, thereby allowing exogenous nucleic acids to enter the cell. This method of transfection can be optimized to accommodate for differences between different cell types/lines and, thus, can be used to transfect mast cells as well as any other bone marrow-derived cell. Furthermore, unlike viral-mediated transfection, electroporation does not impose limits on the size of transfected DNA, nor require extensive preparation. In contrast to lipid-mediated transfection, electroporation can be less toxic and does not result in endosomal trapping of the transfected nucleic acid.
Bio-Rad has developed the MXcell electroporation system specifically for these cells. the MXcell allows you to vary conditions to maximize your transfection efficiency and cell viability. In order to optimize transfection efficiency and minimize cell death, a multitude of electroporation parameters including voltage, capacitance, resistance, and pulse length can be adjusted and evaluated.

<table><tbody><tr><td>Gene Pulser MXcell Electroporation System</td><td>Bio-Rad</td><td>165-2670</td><td></td></tr><tr><td>Gene Pulser Electroporation Buffer</td><td>Bio-Rad</td><td>165-2677</td><td></td></tr></tbody></table>

the preparation of primary hematopoietic cell cultures from murine bone marrow for electroporation

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell  electroporation system and Gene Pulser  electroporation buffer were specifically developed to transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells.This video demonstrates how to establish primary hematopoietic cell cultures from murine bone marrow, and then prepare them for electroporation in the MXcell system. We begin by isolating femur and tibia. Bone marrow from both femur and tibia are then harvested and cultures are established. Cultured bone marrow cells are then transfected and analyzed.

Watch this Scientific Journal Video about The Preparation of Primary Hematopoietic Cell Cultures From Murine Bone Marrow for Electroporation at JoVE.com

The Preparation of Primary Hematopoietic Cell Cultures From Murine Bone Marrow for Electroporation

This procedure describes how to establish primary hematopoietic cell cultures from murine bone marrow and is followed by transfection using the Gene Pulser MXCell electroporation system.

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser ...

<a class="grey_button" href="/video/1047">
ChineseVersion
</a>

the-preparation-primary-hematopoietic-cell-cultures-from-murine-bone

Research

JoVE Journal

Biology

25.7K Views.  Bio-Rad Laboratories, Inc.  ChineseVersion 

Video: The Preparation of Primary Hematopoietic Cell Cultures From Murine Bone Marrow for Electroporation

Highly Efficient Gene Disruption of Murine and Human Hematopoietic Progenitor Cells by CRISPR/Cas9

Advances in the hematopoietic stem cell (HSCs) field have been aided by methods to genetically engineer primary progenitor cells as well as animal models. Complete gene ablation in HSCs required the generation of knockout mice from which HSCs could be isolated, and gene ablation in primary human HSCs was not possible. Viral transduction could be used for knock-down approaches, but these suffered from variable efficacy. In general, genetic manipulation of human and mouse hematopoietic cells was hampered by low efficiencies and extensive time and cost commitments. Recently, CRISPR/Cas9 has dramatically expanded the ability to engineer the DNA of mammalian cells. However, the application of CRISPR/Cas9 to hematopoietic cells has been challenging, mainly due to their low transfection efficiencies, the toxicity of plasmid-based approaches and the slow turnaround time of virus-based protocols.
A rapid method to perform CRISPR/Cas9-mediated gene editing in murine and human hematopoietic stem and progenitor cells with knockout efficiencies of up to 90% is provided in this article. This approach utilizes a ribonucleoprotein (RNP) delivery strategy with a streamlined three-day workflow. The use of Cas9-sgRNA RNP allows for a hit-and-run approach, introducing no exogenous DNA sequences in the genome of edited cells and reducing off-target effects. The RNP-based method is fast and straightforward: it does not require cloning of sgRNAs, virus preparation or specific sgRNA chemical modification. With this protocol, scientists should be able to successfully generate knockouts of a gene of interest in primary hematopoietic cells within a week, including downtimes for oligonucleotide synthesis. This approach will allow a much broader group of users to adapt this protocol for their needs.

A protocol for fast CRISPR/Cas9-mediated gene disruption in mouse and human primary hematopoietic cells is described in this article. Cas9-sgRNA ribonucleoproteins are introduced via electroporation with sgRNAs generated through in vitro transcription and commercial Cas9. High editing efficiencies are achieved with limited time and financial cost.

Advances in the hematopoietic stem cell (HSCs) field have been aided by methods to genetically engineer primary progenitor cells as well as animal models. ...

Genetics

Isolation and Intravenous Injection of Murine Bone Marrow Derived Monocytes

As a subtype of leukocytes and progenitors of macrophages, monocytes are involved in many important processes of organisms and are often the subject of various fields in biomedical science. The method described below is a simple and effective way to isolate murine monocytes from heterogeneous bone marrow.
Bone marrow from the femur and tibia of Balb/c mice is harvested by flushing with phosphate buffered saline (PBS). Cell suspension is supplemented with macrophage-colony stimulating factor (M-CSF) and cultured on ultra-low attachment surfaces to avoid adhesion-triggered differentiation of monocytes. The properties and differentiation of monocytes are characterized at various intervals. Fluorescence activated cell sorting (FACS), with markers like CD11b, CD115, and F4/80, is used for phenotyping. At the end of cultivation, the suspension consists of 45%&#177; 12% monocytes. By removing adhesive macrophages, the purity can be raised up to 86%&#177; 6%. After the isolation, monocytes can be utilized in various ways, and one of the most effective and common methods for in vivo delivery is intravenous tail vein injection. 
This technique of isolation and application is important for mouse model studies, especially in the fields of inflammation or immunology. Monocytes can also be used therapeutically in mouse disease models.

Here we present a protocol that generates large amounts of murine monocytes from heterogeneous bone marrow for translational applications. In comparison to others, this new method helps reduce the number of sacrificed animals and lowers costs by avoiding expensive methods such as high gradient magnetic cell separation (MACS).

As a subtype of leukocytes and progenitors of macrophages, monocytes are involved in many important processes of organisms and are often the subject of ...

Immunology and Infection

Using the Gene Pulser MXcell Electroporation System to Transfect Primary Cells with High Efficiency

It is becoming increasingly apparent that electroporation is the most effective way to introduce plasmid DNA or siRNA into primary cells. The Gene Pulser MXcell electroporation system and Gene Pulser electroporation buffer (Bio-Rad) were specifically developed to easily transfect nucleic acids into mammalian cells and difficult-to-transfect cells, such as primary and stem cells. We will demonstrate how to perform a simple experiment to quickly identify the best electroporation conditions. We will demonstrate how to run several samples through a range of electroporation conditions so that an experiment can be conducted at the same time as optimization is performed. We will also show how optimal conditions identified using 96-well electroporation plates can be used with standard electroporation cuvettes, facilitating the switch from electroporation plates to electroporation cuvettes while maintaining the same electroporation efficiency. In the video, we will also discuss some of the key factors that can lead to the success or failure of electroporation experiments.

This procedure shows how to use the Gene Pulser MXcell electroporation system to rapidly and easily identify the best electroporation conditions for mouse embryonic fibroblasts (MEFs) or other primary cells. Considerations for troubleshooting are also discussed in the associated video.

Phenotypic Analysis and Isolation of Murine Hematopoietic Stem Cells and Lineage-committed Progenitors

The bone marrow is the principal site where HSCs and more mature blood cells lineage progenitors reside and differentiate in an adult organism. HSCs constitute a minute cell population of pluripotent cells capable of generating all blood cell lineages for a life-time1. The molecular dissection of HSCs homeostasis in the bone marrow has important implications in hematopoiesis, oncology and regenerative medicine. We describe the labeling protocol with fluorescent antibodies and the electronic gating procedure in flow cytometry to score hematopoietic progenitor subsets and HSCs distribution in individual mice (Fig. 1). In addition, we describe a method to extensively enrich hematopoietic progenitors as well as long-term (LT) and short term (ST) reconstituting HSCs from pooled bone marrow cell suspensions by magnetic enrichment of cells expressing c-Kit. The resulting cell preparation can be used to sort selected subsets for in vitro and in vivo functional studies (Fig. 2).
Both trabecular osteoblasts2,3 and sinusoidal endothelium4 constitute functional niches supporting HSCs in the bone marrow. Several mechanisms in the osteoblastic niche, including a subset of N-cadherin+ osteoblasts3 and interaction of the receptor tyrosine kinase Tie2 expressed in HSCs with its ligand angiopoietin-15 concur in determining HSCs quiescence. "Hibernation" in the bone marrow is crucial to protect HSCs from replication and eventual exhaustion upon excessive cycling activity6. Exogenous stimuli acting on cells of the innate immune system such as Toll-like receptor ligands7 and interferon-&alpha;6 can also induce proliferation and differentiation of HSCs into lineage committed progenitors. Recently, a population of dormant mouse HSCs within the lin- c-Kit+ Sca-1+ CD150+ CD48- CD34- population has been described8. Sorting of cells based on CD34 expression from the hematopoietic progenitors-enriched cell suspension as described here allows the isolation of both quiescent self-renewing LT-HSCs and ST-HSCs9. A similar procedure based on depletion of lineage positive cells and sorting of LT-HSC with CD48 and Flk2 antibodies has been previously described10. In the present report we provide a protocol for the phenotypic characterization and ex vivo cell cycle analysis of hematopoietic progenitors, which can be useful for monitoring hematopoiesis in different physiological and pathological conditions. Moreover, we describe a FACS sorting procedure for HSCs, which can be used to define factors and mechanisms regulating their self-renewal, expansion and differentiation in cell biology and signal transduction assays as well as for transplantation.

A method to analyse the distribution of bone marrow hematopoietic progenitors in flow cytometry as well as to efficiently isolate highly purified hematopoietic stem cells (HSCs) is described. The isolation procedure is essentially based on magnetic enrichment of c-Kit+ cells and cell sorting to purify HSCs for cellular and molecular studies.

The bone marrow is the principal site where HSCs and more mature blood cells lineage progenitors reside and differentiate in an adult organism. HSCs ...

Lentiviral CRISPR/Cas9-Mediated Genome Editing for the Study of Hematopoietic Cells in Disease Models

Manipulating genes in hematopoietic stem cells using conventional transgenesis approaches can be time-consuming, expensive, and challenging. Benefiting from advances in genome editing technology and lentivirus-mediated transgene delivery systems, an efficient and economical method is described here that establishes mice in which genes are manipulated specifically in hematopoietic stem cells. Lentiviruses are used to transduce Cas9-expressing lineage-negative bone marrow cells with a guide RNA (gRNA) targeting specific genes and a red fluorescence reporter gene (RFP), then these cells are transplanted into lethally-irradiated C57BL/6 mice. Mice transplanted with lentivirus expressing non-targeting gRNA are used as controls. Engraftment of transduced hematopoietic stem cells are evaluated by flow cytometric analysis of RFP-positive leukocytes of peripheral blood. Using this method, ~90% transduction of myeloid cells and ~70% of lymphoid cells at 4 weeks after transplantation can be achieved. Genomic DNA is isolated from RFP-positive blood cells, and portions of the targeted site DNA are amplified by PCR to validate the genome editing. This protocol provides a high-throughput evaluation of hematopoiesis-regulatory genes and can be extended to a variety of mouse disease models with hematopoietic cell involvement.

Described are protocols for the highly efficient genome editing of murine hematopoietic stem and progenitor cells (HSPC) by the CRISPR/Cas9 system to rapidly develop mouse model systems with hematopoietic system-specific gene modifications.

Manipulating genes in hematopoietic stem cells using conventional transgenesis approaches can be time-consuming, expensive, and challenging. Benefiting ...

Economical and Efficient Protocol for Isolating and Culturing Bone Marrow-derived Dendritic Cells from Mice

The demand for dendritic cells (DCs) is gradually increasing as immunology research advances. However, DCs are rare in all tissues. The traditional method for isolating DCs primarily involves inducing bone marrow (BM) differentiation into DCs by injecting large doses (&#62;10 ng/mL) of granulocyte-macrophage colony-stimulating factor/interleukin-4 (GM-CSF/IL-4), making the procedure complex and expensive. In this protocol, using all BM cells cultured in 10 ng/mL GM-CSF/IL-4 medium, after 3-4 half-culture exchanges, up to 2.7 x 107 CD11c+ cells&#160;(DCs) per mouse (two femurs) were harvested with a purity of 80%-95%. After 10 days in culture, the expression of CD11c, CD80, and MHC II increased, whereas the number of cells decreased. The number of cells peaked after 7 days of culture. Moreover, this method only took 10 min to harvest all bone marrow cells, and a high number of DCs were obtained after 1 week of culture.

Here, we present an economical and efficient method to isolate and generate high-purity bone marrow-derived dendritic cells from mice after 7 days of culture with 10 ng/mL GM-CSF/IL-4.

The demand for dendritic cells (DCs) is gradually increasing as immunology research advances. However, DCs are rare in all tissues. The traditional method ...

Optimizing Stromal Cell Isolation from Thymus and Bone Marrow

Stromal Cell Isolation From Hematopoietic Organs

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.

Author Spotlight: Advancing Hematopoietic Research Using Stromal Cell Isolation for Single Cell Sequencing

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 ...

Expression of Fluorescent Fusion Proteins in Murine Bone Marrow-derived Dendritic Cells and Macrophages

Dendritic cells and macrophages are crucial cells that form the first line of defense against pathogens. They also play important roles in the initiation of an adaptive immune response. Experimental work with these cells is rather challenging. Their abundance in organs and tissues is relatively low. As a result, they cannot be isolated in large numbers. They are also difficult to transfect with cDNA constructs. In the murine model, these problems can be partially overcome by in vitro differentiation from bone marrow progenitors in the presence of M-CSF for macrophages or GM-CSF for dendritic cells. In this way, it is possible to obtain large amounts of these cells from very few animals. Moreover, bone marrow progenitors can be transduced with retroviral vectors carrying cDNA constructs during early stages of cultivation prior to their differentiation into bone marrow derived dendritic cells and macrophages. Thus, retroviral transduction followed by differentiation in vitro can be used to express various cDNA constructs in these cells. The ability to express ectopic proteins substantially extends the range of experiments that can be performed on these cells, including live cell imaging of fluorescent proteins, tandem purifications for interactome analyses, structure-function analyses, monitoring of cellular functions with biosensors and many others. In this article, we describe a detailed protocol for retroviral transduction of murine bone marrow derived dendritic cells and macrophages with vectors coding for fluorescently-tagged proteins. On the example of two adaptor proteins, OPAL1 and PSTPIP2, we demonstrate its practical application in flow cytometry and microscopy. We also discuss the advantages and limitations of this approach.

In this article, we provide a detailed protocol for the expression of fluorescent fusion proteins in murine bone marrow derived dendritic cells and macrophages. The method is based on the transduction of bone marrow progenitors with retroviral constructs followed by differentiation into macrophages and dendritic cells in vitro.

Dendritic cells and macrophages are crucial cells that form the first line of defense against pathogens. They also play important roles in the initiation ...

Ex Vivo Expansion and Genetic Manipulation of Mouse Hematopoietic Stem Cells in Polyvinyl Alcohol-Based Cultures

Self-renewing&#160;multipotent&#160;hematopoietic stem cells (HSCs) are an important cell type due to their abilities to support hematopoiesis throughout life and reconstitute the entire blood system following transplantation. HSCs are used clinically in stem cell transplantation therapies, which represent curative treatment for a range of blood diseases. There is substantial interest in both understanding the mechanisms that regulate HSC activity and hematopoiesis, and developing new HSC-based therapies. However, the stable culture and expansion of HSCs ex vivo has been a major barrier in studying these stem cells in a tractable ex vivo system. We recently developed a polyvinyl alcohol-based culture system that can support the long-term and large-scale expansion of transplantable mouse HSCs and methods to genetically edit them. This protocol describes methods to culture and genetically manipulate mouse HSCs via electroporation and lentiviral transduction. This protocol is expected to be useful to a wide range of experimental hematologists interested in HSC biology and hematopoiesis.

Ex Vivo Expansion and Genetic Manipulation of Mouse Hematopoietic Stem Cells in Polyvinyl Alcohol-Based Cultures

Presented here is a protocol to initiate, maintain, and analyze mouse hematopoietic stem cell cultures using ex vivo polyvinyl alcohol-based expansion, as well as methods to genetically manipulate them by lentiviral transduction and electroporation.

Self-renewing&#160;multipotent&#160;hematopoietic stem cells (HSCs) are an important cell type due to their abilities to support hematopoiesis throughout ...

Utilizing Low Oxygen Tension to Reduce Hematopoietic Cells in Murine Bone Marrow Stromal Cell Cultures

Currently, there remains a lack of universally accepted markers to prospectively isolate a homogeneous population of skeletal stem cells (SSCs). For this reason, BMSCs, which support hematopoiesis and contribute to all the functions of the skeleton, continue to be widely used to study multipotent mesenchymal progenitors (MMPs) and to infer SSC function. Moreover, given the breadth of transgenic murine models used to study musculoskeletal diseases, the use of BMSCs also serves as a powerful tool to examine the molecular mechanisms regulating MMPs and SSCs. However, common isolation procedures for murine BMSCs result in over 50% of recovered cells being of hematopoietic origins, potentially hindering the interpretation of the data generated during these studies. Here, we describe a method using low oxygen tension or hypoxia for the selective elimination of CD45+ cells in BMSC cultures. Importantly, this method can be easily implemented to not only reduce hemopoietic contaminants but to also enhance the percentage of MMPs and putative SSCs in BMSC cultures.

A routine culture of bone marrow stromal cells (BMSCs) leads to the isolation of heterogeneous cell populations, with many cells being of hematopoietic origins. Here, we describe a method that utilizes low oxygen tension to greatly reduce hematopoietic contaminants in murine BMSC cultures.

Currently, there remains a lack of universally accepted markers to prospectively isolate a homogeneous population of skeletal stem cells (SSCs). For this ...

The Preparation of Primary Hematopoietic Cell Cultures From Murine Bone Marrow for Electroporation

Transcript

Samenvatting

Meer video's verkennen