This work was supported by the Federal Ministry of Education and Research Germany (FKZ 0312138A and FKZ 316159), the State Mecklenburg-Western Pomerania with EU Structural Funds (ESF/IVWM-B34-0030/10 and ESF/IVBM-B35-0010/12), and the DFG (DA1296/2-1), the German Heart Foundation (F/01/12), the BMBF (VIP+ 00240) and the DAMP Foundation. In addition, F.H. and P.M. are supported by the FORUN Program of Rostock University Medical Centre (889001).

The authors declare no conflict of interest.

In recent years, CD133+ SCs have emerged as a promising cell population for SC-based therapies as evidenced by several phase I, II, and III clinical trials43,44,45,46,47,48,49,50,51,...

CD133+ SCs represent a heterogeneous stem and progenitor cell population with promising potential for regenerative medicine. Their hematopoietic, endothelial, and myogenic differentiation potential1,2,3 enables the CD133+ cells, e.g., to contribute to neovascularization processes through differentiation into newly forming vessels and activation of pro-angiogenic signaling by paracrine mechanisms4,5,6,7.
Despite their high potential demonstrated in more than 30 approved clinical trials (ClinicalTrails.gov), their therapeutic outcome is still under controversial discussion4. Indeed, a clinical application of SCs is hampered by low retention in the organ of interest and massive initial cell death5,8,9. Additional engineering of CD133+ SCs prior transplantation could help overcome these challenges.
One prerequisite for an efficient cell therapy would be the reduction of the massive initial cell death to enhance the engraftment of therapeutic relevant cells10. Current studies demonstrated an immense cell loss of 90&#8211;99% in highly perfused organs such as the brain and heart during the first 1&#8211;2 h, independent of the transplanted cell type or application route11,12,13,14,15,16,17,18,19,20,21. SC labeling using magnetic nanoparticles (MNPs) enables an innovative non-invasive strategy to target cells to the site of interest22,23,24,25,26 and simultaneously allows cell monitoring using MRI27 and magnetic particle imaging (MPI). The most efficient in vivo studies applying magnetized cell targeting used cell retention after local administration in preference to cell guidance after intravenous injection23,24,28. Therefore, our group designed a delivery system consisting of superparamagnetic iron oxide nanoparticles29. With this technique, CD133+ SCs and human umbilical vein endothelial cells (HUVECs) could efficiently be targeted, as demonstrated by in vitro attempts30,31.
Another hurdle for SC therapies is the hostile inflammatory environment of the affected tissue after transplantation, which contributes to the initial cell death32. In addition to several pre-conditioning studies, the application of therapeutic relevant miRs was tested33; it has been successfully demonstrated that anti-apoptotic miRs inhibit apoptosis in vitro and enhance cell engraftment in vivo33. These small molecules, composed of 20&#8211;25 nucleotides, play a crucial role as posttranscriptional modulators of messenger RNAs (mRNAs), and thus affect stem cell fate and behavior34. Moreover, the exogenous introduction of miRs avoid the undesired stable integration into the host genome34.
Current attempts for efficient introduction of nucleic acids (NAs) into primary SCs are mostly based on recombinant viruses8,35. Despite the high transfection efficiency, recombinant virus manipulation presents a major obstacle for a bench-to-bedside translation, e.g., uncontrollable gene expression, pathogenicity, immunogenicity, and insertional mutagenesis35,36. Therefore, non-viral delivery systems such as polymer-based constructs are critical to develop. Among those, polyethylenimine (PEI) represents a valid delivery vehicle offering benefits for miRs such as NA condensation to protect from degradation, cellular uptake, and intracellular release through endosomal escape37,38. Furthermore, miR-PEI complexes demonstrated a high biocompatibility in clinical trials39. Therefore, our delivery system consists of a biotinylated branched 25 kDa PEI bound to a streptavidin-coated MNP-core30,31,40.
In this manuscript, we present a comprehensive protocol describing (i) the manual isolation of CD133+ SC from human bone marrow (BM) donation with a detailed characterization of the SC product and (ii) an efficient and gentle transfection strategy of a magnetically non-viral polymer-based delivery system for genetic engineering of CD133+ SCs using miRs. CD133+ SCs are isolated and magnetically enriched from human sternal BM aspirates using a surface antibody-based magnetic-activated cell sorting (MACS) system. Afterwards, the cell viability as well as the cell purity are analyzed using flow cytometry. Subsequently, miR/PEI/MNP complexes are prepared and CD133+ SCs are transfected. 18 h after transfection, the uptake efficiency and the impact of transfection on SC marker expression and cell viability are analyzed. Moreover, evaluation of the intracellular distribution of the transfection complex compounds is performed using four-color labeling and structured illumination microscopy (SIM).

<table><tbody><tr><td>7-AAD</td><td>BD Biosciences</td><td>559925</td><td></td></tr><tr><td>Acetic Acid with Methylene Blue</td><td>Stemcell Technologies</td><td>7060</td><td>3%</td></tr><tr><td>anti-CD133/2-PE (clone: 293C3)</td><td>Miltenyi Biotec GmbH</td><td>130-090-853</td><td></td></tr><tr><td>anti-CD34-FITC (clone: AC136)</td><td>Miltenyi Biotec GmbH</td><td>130-081-001</td><td></td></tr><tr><td>anti-CD45-APC-H7 (clone: 2D1)</td><td>BD Biosciences</td><td>560178</td><td></td></tr><tr><td>rhodamine dye; Atto 565 dye conjugated to biotin</td><td>ATTO-TEC GmbH</td><td>AD 565-71</td><td></td></tr><tr><td>BD FACS LSRII flow cytometer</td><td>BD Biosciences</td><td></td><td></td></tr><tr><td>BD FACSDiva Software 6.1.2</td><td>BD Biosciences</td><td></td><td></td></tr><tr><td>BSA</td><td>Sigma-Aldrich GmbH</td><td>A7906</td><td></td></tr><tr><td>CD133 antibody-linked superparamagnetic iron dextran particles; CD133 MicroBead Kit</td><td>Miltenyi Biotec GmbH</td><td>130-097-049</td><td></td></tr><tr><td>collagenase B</td><td>Roche Diagnostics GmbH</td><td>11088831001</td><td></td></tr><tr><td>counting chamber</td><td>Paul Marienfeld GmbH &amp;amp; Co. KG</td><td></td><td></td></tr><tr><td>Cyanine 3 dye labelled precursor miR; Cy3 Dye-Labeled Pre-miR Negative Control #1</td><td>Ambion</td><td>AM17120</td><td></td></tr><tr><td>Cyanine 5 dye miR labelling kit; Cy5 dye Label IT miRNA Labeling Kit</td><td>Mirus Bio</td><td>MIR 9650</td><td></td></tr><tr><td>DNAse I</td><td>Roche Diagnostics GmbH</td><td>10104159001</td><td>(100 U/mL)</td></tr><tr><td>ELYRA PS.1 LSM 780 confocal microscope</td><td>Carl Zeiss Jena GmbH</td><td></td><td></td></tr><tr><td>FcR Blocking Reagent, human</td><td>Miltenyi Biotec GmbH</td><td>130-059-901</td><td></td></tr><tr><td>bright green protein labeling kit; Oregon Green 488 Protein Labeling Kit</td><td>Thermo Fisher Scientific</td><td>O10241</td><td></td></tr><tr><td>aqueous mounting medium; Fluoroshield</td><td>Sigma-Aldrich GmbH</td><td>F6182</td><td></td></tr><tr><td>density gradient centrifugation tube; Leukosep Centrifuge Tube</td><td>Greiner Bio-One</td><td>89048-932</td><td></td></tr><tr><td>MACS magnet holder; MACS MultiStand</td><td>Miltenyi Biotec GmbH</td><td>130-042-303</td><td></td></tr><tr><td>MACS pre-separation filter</td><td>Miltenyi Biotec GmbH</td><td>130-041-407</td><td>30 &amp;micro;m</td></tr><tr><td>MACS separation column (MS / LS)</td><td>Miltenyi Biotec GmbH</td><td>130-042-201 / 130-042-401</td><td></td></tr><tr><td>MACS permanent magnet; MACS Separator</td><td>Miltenyi Biotec GmbH</td><td>130-042-302</td><td></td></tr><tr><td>Millex-HV PVDF Filter</td><td>Merck</td><td>SLHV013SL</td><td>0.45 &amp;mu;m</td></tr><tr><td>mouse IgG 2b-PE</td><td>Miltenyi Biotec GmbH</td><td>130-092-215</td><td></td></tr><tr><td>amine reactive dye; Near-IR LIVE/DEAD Fixable Dead Cell Stain Kit</td><td>Thermo Fisher Scientific</td><td>L10119</td><td></td></tr><tr><td>human lymphocyte separating medium; Pancoll</td><td>Pan Biotech GmbH</td><td>P04-60500</td><td>density: 1.077 g/mL</td></tr><tr><td>PBS</td><td>Pan Biotech GmbH</td><td>P04-53500</td><td>without Ca and Mg</td></tr><tr><td>PEI</td><td>Sigma-Aldrich GmbH</td><td>408727</td><td>branched; 25 kDa</td></tr><tr><td>Penicillin/Streptomycin</td><td>Thermo Fisher Scientific</td><td>15140122</td><td>100 U/mL, 100 &amp;mu;g/mL</td></tr><tr><td>PFA</td><td>Merck Schuchardt OHG</td><td>1040051000</td><td></td></tr><tr><td>unlabelled precursor miR; Pre-miR miRNA Precursor Negative Control #1</td><td>Ambion</td><td>AM17110</td><td></td></tr><tr><td>RBC lysis buffer</td><td>eBioscience</td><td>00-4333-57</td><td></td></tr><tr><td>RNAse decontamination solution; RNaseZap</td><td>Thermo Fisher Scientific</td><td>AM9780</td><td></td></tr><tr><td>human lymphocyte medium; Roswell Park Memorial Institute (RPMI) 1640 medium</td><td>Pan Biotech GmbH</td><td>P04-16500</td><td></td></tr><tr><td>recombinant human cytokine supplement; StemSpan CC100</td><td>Stemcell Technologies</td><td>2690</td><td></td></tr><tr><td>serum-free haematopoietic cell expansion medium; StemSpan H3000</td><td>Stemcell Technologies</td><td>9800</td><td></td></tr><tr><td>Streptavidin MagneSphere Paramagnetic Particles</td><td>Promega Corporation</td><td>Z5481</td><td></td></tr><tr><td>Trypan Blue solution</td><td>Sigma-Aldrich GmbH</td><td>T8154</td><td>0.4 %</td></tr><tr><td>UltraPure EDTA</td><td>Thermo Fisher Scientific</td><td>15575020</td><td>0.5 M; pH 8.0</td></tr><tr><td>ZEN2011 software</td><td>Carl Zeiss Jena GmbH</td><td></td><td></td></tr><tr><td>NanoDrop 1000 Spectrophotometer</td><td>Thermo Fisher Scientific</td><td></td><td></td></tr><tr><td>Sonorex RK 100 SH sonicating water bath</td><td>Bandelin electronic</td><td></td><td>Ultrasonic nominal output: 80 W; Ultrasonic frequency: 35 kHz</td></tr></tbody></table>

protocol for microrna transfer into adult bone marrow-derived hematopoietic stem cells to enable cell engineering combined with magnetic targeting

While CD133+ hematopoietic stem cells (SCs) have been proven to provide high potential in the field of regenerative medicine, their low retention rates after injection into injured tissues as well as the observed massive cell death rates lead to very restricted therapeutic effects. To overcome these limitations, we sought to establish a non-viral based protocol for suitable cell engineering prior to their administration. The modification of human CD133+ expressing SCs using microRNA (miR) loaded magnetic polyplexes was addressed with respect to uptake efficiency and safety as well as the targeting potential of the cells. Relying on our protocol, we can achieve high miR uptake rates of 80&#8211;90% while the CD133+ stem cell properties remain unaffected. Moreover, these modified cells offer the option of magnetic targeting. We describe here a safe and highly efficient procedure for the modification of CD133+ SCs. We expect this approach to provide a standard technology for optimization of therapeutic stem cell effects and for monitoring of the administered cell product via magnetic resonance imaging (MRI).

The presented protocol describes a manual isolation and magnetic enrichment of human BM-derived CD133+ SCs with a subsequent virus independent cell engineering strategy, as a non-invasive technology for in vitro cell manipulation and in vivo monitoring tool.
This three-step isolation technology permits a separation of MNCs from the pre-digested sternal BM through density gradient centrifugation. Afte...

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Protocol for MicroRNA Transfer into Adult Bone Marrow-derived Hematopoietic Stem Cells to Enable Cell Engineering Combined with Magnetic Targeting

This protocol illustrates a safe and efficient procedure to modify CD133+ hematopoietic stem cells. The presented non-viral, magnetic polyplex-based approach may provide a basis for the optimization of therapeutic stem cell effects as well as for monitoring the administered cell product via magnetic resonance imaging.

While CD133+ hematopoietic stem cells (SCs) have been proven to provide high potential in the field of regenerative medicine, their low retention rates ...

protocol-for-microrna-transfer-into-adult-bone-marrow-derived

Research

JoVE Journal

Bioengineering

6.6K Views.  Rostock University Medical Center. Dit protocol illustreert een veilige en efficiënte procedure voor het wijzigen van de CD133+ hematopoietische stamcellen. De voorgestelde niet-virale, magnetische polyplex gebaseerde benadering verschaffen een basis voor de optimalisatie van de cel van de stam van de therapeutische effecten ook monitoring van het product door de overheid gereguleerde cel via magnetische resonantie beeldvorming.

Video: Protocol for MicroRNA Transfer into Adult Bone Marrow-derived Hematopoietic Stem Cells to Enable Cell Engineering Combined with Magnetic Targeting

Reprogramming Mouse Embryonic Fibroblasts with Transcription Factors to Induce a Hemogenic Program

This protocol details the induction of a hemogenic program in mouse embryonic fibroblasts (MEFs) via overexpression of transcription factors (TFs). We first designed a reporter screen using MEFs from human CD34-tTA/TetO-H2BGFP (34/H2BGFP) double transgenic mice. CD34+ cells from these mice label H2B histones with GFP, and cease labeling upon addition of doxycycline (DOX). MEFS were transduced with candidate TFs and then observed for the emergence of GFP+ cells that would indicate the acquisition of a hematopoietic or endothelial cell fate. Starting with 18 candidate TFs, and through a process of combinatorial elimination, we obtained a minimal set of factors that would induce the highest percentage of GFP+ cells. We found that Gata2, Gfi1b, and cFos were necessary and the addition of Etv6 provided the optimal induction. A series of gene expression analyses done at different time points during the reprogramming process revealed that these cells appeared to go through a precursor cell that underwent an endothelial to hematopoietic transition (EHT). As such, this reprogramming process mimics developmental hematopoiesis "in a dish," allowing study of hematopoiesis in vitro and a platform to identify the mechanisms that underlie this specification. This methodology also provides a framework for translation of this work to the human system in the hopes of generating an alternative source of patient-specific hematopoietic stem cells (HSCs) for a number of applications in the treatment and study of hematologic diseases.

The protocol described here details the induction of a hemogenic program in mouse embryonic fibroblasts via overexpression of a minimal set of transcription factors. This technology may be translated to the human system to provide platforms for future study of hematopoiesis, hematologic disease, and hematopoietic stem cell transplant.

This protocol details the induction of a hemogenic program in mouse embryonic fibroblasts (MEFs) via overexpression of transcription factors (TFs). We ...

Developmental Biology

Isolation, Characterization and MicroRNA-based Genetic Modification of Human Dental Follicle Stem Cells

To date, several stem cell types at different developmental stages are in the focus for the treatment of degenerative diseases. Yet, certain aspects, such as initial massive cell death and low therapeutic effects, impaired their broad clinical translation. Genetic engineering of stem cells prior to transplantation emerged as a promising method to optimize therapeutic stem cell effects. However, safe and efficient gene delivery systems are still lacking. Therefore, the development of suitable methods may provide an approach to resolve current challenges in stem cell-based therapies.
The present protocol describes the extraction and characterization of human dental follicle stem cells (hDFSCs) as well as their non-viral genetic modification. The postnatal dental follicle unveiled as a promising and easily accessible source for harvesting adult multipotent stem cells possessing high proliferation potential. The described isolation procedure presents a simple and reliable method to harvest hDFSCs from impacted wisdom teeth. Also this protocol comprises methods to define stem cell characteristics of isolated cells. For genetic engineering of hDFSCs, an optimized cationic lipid-based transfection strategy is presented enabling highly efficient microRNA introduction without causing cytotoxic effects. MicroRNAs are suitable candidates for transient cell manipulation, as these small translational regulators control the fate and behavior of stem cells without the hazard of stable genome integration. Thus, this protocol represents a safe and efficient procedure for engineering of hDFSCs that may become important for optimizing their therapeutic efficacy.

This protocol describes the transient genetic engineering of dental stem cells extracted from the human dental follicle. The applied non-viral modification strategy may become a basis for the improvement of therapeutic stem cell products.

To date, several stem cell types at different developmental stages are in the focus for the treatment of degenerative diseases. Yet, certain aspects, such ...

Genetics

Isolating, Sequencing and Analyzing Extracellular MicroRNAs from Human Mesenchymal Stem Cells

Extracellular and circulating RNAs (exRNA) are produced by many cell types of the body and exist in numerous bodily fluids such as saliva, plasma, serum, milk and urine. One subset of these RNAs are the posttranscriptional regulators &#8211; microRNAs (miRNAs). To delineate the miRNAs produced by specific cell types, in vitro culture systems can be used to harvest and profile exRNAs derived from one subset of cells. The secreted factors of mesenchymal stem cells are implicated in alleviating numerous diseases and is used as the in vitro model system here. This paper describes the process of collection, purification of small RNA and library generation to sequence extracellular miRNAs. ExRNAs from culture media differ from cellular RNA by being low RNA input samples, which calls for optimized procedures. This protocol provides a comprehensive guide to small exRNA sequencing from culture media, showing quality control checkpoints at each step during exRNA purification and sequencing.

This protocol demonstrates how to purify extracellular microRNAs from cell culture media for small RNA library construction and next generation sequencing. Various quality control checkpoints are described to allow readers to understand what to expect when working with low input samples like exRNAs.

Extracellular and circulating RNAs (exRNA) are produced by many cell types of the body and exist in numerous bodily fluids such as saliva, plasma, serum, ...

Preparation and Gene Modification of Nonhuman Primate Hematopoietic Stem and Progenitor Cells

Hematopoietic stem and progenitor cell (HSPC) transplantation has been a cornerstone therapy for leukemia and other cancers for nearly half a century, underlies the only known cure of human immunodeficiency virus (HIV-1) infection, and shows immense promise in the treatment of genetic diseases such as beta thalassemia. Our group has developed a protocol to model HSPC gene therapy in nonhuman primates (NHPs), allowing scientists to optimize many of the same reagents and techniques that are applied in the clinic. Here, we describe methods for purifying CD34+ HSPCs and long-term persisting hematopoietic stem cell (HSC) subsets from primed bone marrow (BM). Identical techniques can be employed for the purification of other HSPC sources (e.g., mobilized peripheral blood stem cells [PBSCs]). Outlined is a 2 day protocol in which cells are purified, cultured, modified with lentivirus (LV), and prepared for infusion back into the autologous host. Key readouts of success include the purity of the CD34+ HSPC population, the ability of purified HSPCs to form morphologically distinct colonies in semisolid media, and, most importantly, gene modification efficiency. The key advantage to HSPC gene therapy is the ability to provide a source of long-lived cells that give rise to all hematopoietic cell types. As such, these methods have been used to model therapies for cancer, genetic diseases, and infectious diseases. In each case, therapeutic efficacy is established by enhancing the function of distinct HSPC progeny, including red blood cells, T cells, B cells, and/or myeloid subsets. The methods to isolate, modify, and prepare HSPC products are directly applicable and translatable to multiple diseases in human patients.

The goal of this protocol is to isolate nonhuman primate CD34+ cells from primed bone marrow, to gene-modify these cells with lentiviral vectors, and to prepare a product for infusion into the autologous host. The total protocol length is approximately 48 h.

Hematopoietic stem and progenitor cell (HSPC) transplantation has been a cornerstone therapy for leukemia and other cancers for nearly half a century, ...

A Guide to Precise Gene Disruption in Primary Bone Marrow-Derived Macrophages

High-Efficiency Gene Disruption in Primary Bone Marrow-Derived Macrophages Using Electroporated Cas9-sgRNA Complexes

Bone marrow-derived macrophages (BMDMs) from mice are a key tool for studying the complex biology of tissue macrophages. As primary cells, they model the physiology of macrophages in vivo more closely than immortalized macrophage cell lines and can be derived from mice already carrying defined genetic changes. However, disrupting gene function in BMDMs remains technically challenging. Here, we provide a protocol for efficient CRISPR/Cas9 genome editing in BMDMs, which allows for the introduction of small insertions and deletions (indels) that result in frameshift mutations that disrupt gene function. The protocol describes how to synthesize single-guide RNAs (sgRNA-Cas9) and form purified sgRNA-Cas9 ribonucleoprotein complexes (RNPs) that can be delivered by electroporation. It also provides an efficient method for monitoring editing efficiency using routine Sanger sequencing and a freely available online analysis program. The protocol can be performed within 1 week and does not require plasmid construction; it typically results in 85% to 95% editing efficiency.

Author Spotlight: Efficient CRISPR/Cas9 Genome Editing in Bone Marrow-Derived Macrophages for Precise Gene Disruption

This protocol describes the procedure for genome editing in mouse bone marrow-derived macrophages using Cas9-sgRNA ribonucleoprotein complexes assembled in vitro and delivered by electroporation.

Bone marrow-derived macrophages (BMDMs) from mice are a key tool for studying the complex biology of tissue macrophages. As primary cells, they model the ...

Cell Labeling and Targeting with Superparamagnetic Iron Oxide Nanoparticles

Targeted delivery of cells and therapeutic agents would benefit a wide range of biomedical applications by concentrating the therapeutic effect at the target site while minimizing deleterious effects to off-target sites. Magnetic cell targeting is an efficient, safe, and straightforward delivery technique. Superparamagnetic iron oxide nanoparticles (SPION) are biodegradable, biocompatible, and can be endocytosed into cells to render them responsive to magnetic fields. The synthesis process involves creating magnetite (Fe3O4) nanoparticles followed by high-speed emulsification to form a poly(lactic-co-glycolic acid) (PLGA) coating. The PLGA-magnetite SPIONs are approximately 120 nm in diameter including the approximately 10 nm diameter magnetite core. When placed in culture medium, SPIONs are naturally endocytosed by cells and stored as small clusters within cytoplasmic endosomes. These particles impart sufficient magnetic mass to the cells to allow for targeting within magnetic fields. Numerous cell sorting and targeting applications are enabled by rendering various cell types responsive to magnetic fields. SPIONs have a variety of other biomedical applications as well including use as a medical imaging contrast agent, targeted drug or gene delivery, diagnostic assays, and generation of local hyperthermia for tumor therapy or tissue soldering.

Targeted cell delivery is useful in a variety of biomedical applications. The goal of this protocol is to use superparamagnetic iron oxide nanoparticles (SPION) to label cells and thereby enable magnetic cell targeting approaches for a high degree of control over cell delivery and localization.

Targeted delivery of cells and therapeutic agents would benefit a wide range of biomedical applications by concentrating the therapeutic effect at the ...

Engineering Oncogenic Heterozygous Gain-of-Function Mutations in Human Hematopoietic Stem and Progenitor Cells

Throughout their lifetime, hematopoietic stem and progenitor cells (HSPCs) acquire somatic mutations. Some of these mutations alter HSPC functional properties such as proliferation and differentiation, thereby promoting the development of hematologic malignancies. Efficient and precise genetic manipulation of HSPCs is required to model, characterize, and better understand the functional consequences of recurrent somatic mutations. Mutations can have a deleterious effect on a gene and result in loss-of-function (LOF) or, in stark contrast, may enhance function or even lead to novel characteristics of a particular gene, termed gain-of-function (GOF). In contrast to LOF mutations, GOF mutations almost exclusively occur in a heterozygous fashion. Current genome-editing protocols do not allow for the selective targeting of individual alleles, hampering the ability to model heterozygous GOF mutations. Here, we provide a detailed protocol on how to engineer heterozygous GOF hotspot mutations in human HSPCs by combining CRISPR/Cas9-mediated homology-directed repair and recombinant AAV6 technology for efficient DNA donor template transfer. Importantly, this strategy makes use of a dual fluorescent reporter system to allow for the tracking and purification of successfully heterozygously edited HSPCs. This strategy can be employed to precisely investigate how GOF mutations affect HSPC function and their progression toward hematological malignancies.

Novel strategies to faithfully model somatic mutations in hematopoietic stem and progenitor cells (HSPCs) are necessary to better study hematopoietic stem cell biology and hematological malignancies. Here, a protocol to model heterozygous gain-of-function mutations in HSPCs by combining the use of CRISPR/Cas9 and dual rAAV donor transduction is described.

Throughout their lifetime, hematopoietic stem and progenitor cells (HSPCs) acquire somatic mutations. Some of these mutations alter HSPC functional ...

Cancer Research

Identification and Isolation of Oligopotent and Lineage-committed Myeloid Progenitors from Mouse Bone Marrow

Myeloid progenitors that yield neutrophils, monocytes and dendritic cells (DCs) can be identified in and isolated from the bone marrow of mice for hematological and immunological analyses. For example, studies of the cellular and molecular properties of myeloid progenitor populations can reveal mechanisms underlying leukemic transformation, or demonstrate how the immune system responds to pathogen exposure. Previously described flow cytometry strategies for myeloid progenitor identification have enabled significant advances in many fields, but the fractions they identify are very heterogeneous. The most commonly used gating strategies define bone marrow fractions that are enriched for the desired populations, but also contain large numbers of &#34;contaminating&#34; progenitors. Our recent studies have resolved much of this heterogeneity, and the protocol we present here permits the isolation of 6 subpopulations of oligopotent and lineage-committed myeloid progenitors from 2 previously described bone marrow fractions. The protocol describes 3 stages: 1) isolation of bone marrow cells, 2) enrichment for hematopoietic progenitors by magnetic-activated cell sorting (lineage depletion by MACS), and 3) identification of myeloid progenitor subsets by flow cytometry (including fluorescence-activated cell sorting, FACS, if desired). This approach permits progenitor quantification and isolation for a variety of in vitro and in vivo applications, and has already yielded novel insight into pathways and mechanisms of neutrophil, monocyte, and DC differentiation.

We demonstrate how to identify and isolate 6 subsets of myeloid progenitors from murine bone marrow using a combination of magnetic and fluorescence sorting (MACS and FACS). This protocol can be used for in vitro culture assays (methylcellulose or liquid cultures), in vivo adoptive transfer experiments, and RNA/protein analyses.

Myeloid progenitors that yield neutrophils, monocytes and dendritic cells (DCs) can be identified in and isolated from the bone marrow of mice for ...

Immunology and Infection

Preparation and In Vitro Characterization of Magnetized miR-modified Endothelial Cells

To date, the available surgical and pharmacological treatments for cardiovascular diseases (CVD) are limited and often palliative. At the same time, gene and cell therapies are highly promising alternative approaches for CVD treatment. However, the broad clinical application of gene therapy is greatly limited by the lack of suitable gene delivery systems. The development of appropriate gene delivery vectors can provide a solution to current challenges in cell therapy. In particular, existing drawbacks, such as limited efficiency and low cell retention in the injured organ, could be overcome by appropriate cell engineering (i.e., genetic) prior to transplantation. The presented protocol describes the efficient and safe transient modification of endothelial cells using a polyethyleneimine superparamagnetic magnetic nanoparticle (PEI/MNP)-based delivery vector. Also, the algorithm and methods for cell characterization are defined. The successful intracellular delivery of microRNA (miR) into human umbilical vein endothelial cells (HUVECs) has been achieved without affecting cell viability, functionality, or intercellular communication. Moreover, this approach was proven to cause a strong functional effect in introduced exogenous miR. Importantly, the application of this MNP-based vector ensures cell magnetization, with accompanying possibilities of magnetic targeting and non-invasive MRI tracing. This may provide a basis for magnetically guided, genetically engineered cell therapeutics that can be monitored non-invasively with MRI.

Preparation and In Vitro Characterization of Magnetized miR-modified Endothelial Cells

This manuscript describes the efficient, non-viral delivery of miR to endothelial cells by a PEI/MNP vector and their magnetization. Thus, in addition to genetic modification, this approach allows for magnetic cell guidance and MRI detectability. The technique can be used to improve the characteristics of therapeutic cell products.

To date, the available surgical and pharmacological treatments for cardiovascular diseases (CVD) are limited and often palliative. At the same time, gene ...

Medicine

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 ...

Protocol for MicroRNA Transfer into Adult Bone Marrow-derived Hematopoietic Stem Cells to Enable Cell Engineering Combined with Magnetic Targeting

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