Generation of Human Induced Pluripotent Stem Cells from Peripheral Blood Using the STEMCCA Lentiviral Vector

Summary

Here we show a simple and effective protocol for the generation of human iPSCs from 3-4 ml of peripheral blood using a single lentiviral reprogramming vector. Reprogramming of readily available blood cells promises to accelerate the utilization of iPSC technology by making it accessible to a broader research community.

Abstract

Through the ectopic expression of four transcription factors, Oct4, Klf4, Sox2 and cMyc, human somatic cells can be converted to a pluripotent state, generating so-called induced pluripotent stem cells (iPSCs)^1-4. Patient-specific iPSCs lack the ethical concerns that surround embryonic stem cells (ESCs) and would bypass possible immune rejection. Thus, iPSCs have attracted considerable attention for disease modeling studies, the screening of pharmacological compounds, and regenerative therapies⁵.

We have shown the generation of transgene-free human iPSCs from patients with different lung diseases using a single excisable polycistronic lentiviral Stem Cell Cassette (STEMCCA) encoding the Yamanaka factors⁶. These iPSC lines were generated from skin fibroblasts, the most common cell type used for reprogramming. Normally, obtaining fibroblasts requires a skin punch biopsy followed by expansion of the cells in culture for a few passages. Importantly, a number of groups have reported the reprogramming of human peripheral blood cells into iPSCs^7-9. In one study, a Tet inducible version of the STEMCCA vector was employed⁹, which required the blood cells to be simultaneously infected with a constitutively active lentivirus encoding the reverse tetracycline transactivator. In contrast to fibroblasts, peripheral blood cells can be collected via minimally invasive procedures, greatly reducing the discomfort and distress of the patient. A simple and effective protocol for reprogramming blood cells using a constitutive single excisable vector may accelerate the application of iPSC technology by making it accessible to a broader research community. Furthermore, reprogramming of peripheral blood cells allows for the generation of iPSCs from individuals in which skin biopsies should be avoided (i.e. aberrant scarring) or due to pre-existing disease conditions preventing access to punch biopsies.

Here we demonstrate a protocol for the generation of human iPSCs from peripheral blood mononuclear cells (PBMCs) using a single floxed-excisable lentiviral vector constitutively expressing the 4 factors. Freshly collected or thawed PBMCs are expanded for 9 days as described^10,11 in medium containing ascorbic acid, SCF, IGF-1, IL-3 and EPO before being transduced with the STEMCCA lentivirus. Cells are then plated onto MEFs and ESC-like colonies can be visualized two weeks after infection. Finally, selected clones are expanded and tested for the expression of the pluripotency markers SSEA-4, Tra-1-60 and Tra-1-81. This protocol is simple, robust and highly consistent, providing a reliable methodology for the generation of human iPSCs from readily accessible 4 ml of blood.

Protocol

1. Isolation and Expansion of Peripheral Blood Mononuclear Cells (PBMCs)

DAY 0

1. Draw 4 ml of peripheral blood into a BD Vacutainer CPT Cell Preparation Tube with sodium citrate. Invert the tube 8 to 10 times and centrifuge at 1,800 x g for 30 min at room temperature. Ideally, this step should be done within 2 hr of collection.
2. Collect the mononuclear cells (MCs) by pipetting the buffy coat (cell layer between gel barrier and plasma) into a sterile 15 ml conical centrifuge tube. Bring total volume to 10 ml with sterile phosphate-buffered saline (PBS), invert several times and centrifuge at 300 x g for 15 min.
3. Resu....

Results

We demonstrate a simple and effective protocol for the generation of human iPSCs from PBMCs using a single lentiviral vector. Figure 1A shows a schematic representation of the protocol. The blood is collected into a BD Vacutainer CPT Cell Preparation Tube with sodium citrate, and after centrifugation, mononuclear cells can be collected from the interface between the polyester gel and the plasma (buffy coat) (Figure 1B). The isolated PBMCs are then expanded in culture for 9 days. .......

Discussion

We herein describe the use of the STEMCCA lentiviral vector to generate human iPSCs from mononuclear cells isolated from a few milliliters of freshly collected peripheral blood. The protocol can also be used to reprogram frozen PBMCs (obtained directly from the buffy coat), a detail of significant practical implications when utilizing donor cells acquired from a distant location. Before the induction of reprogramming, isolated PBMCs must undergo a critical expansion step that renders a healthy proliferating population of.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
BD Vacutainer CPT Cell Preparation Tube with sodium citrate	BD Biosciences	362760
QBSF-60 Stem Cell Medium	Quality Biological	160-204-101
IMDM	Invitrogen	12440
DMEM/F12	Invitrogen	11330
FBS	Atlanta Biologicals	S10250
Knockout Serum Replacement	Invitrogen	10828
Primocin	Invivogen	ant-pm-2
Pen/Strep	Invitrogen	15140
L-Glutamine	Invitrogen	25030
Non-Essential Amino Acids	Invitrogen	11140
β-mercapt–thanol	MP Biomedicals	190242
Ascorbic Acid	Sigma	A4544
IGF-1	R&D Systems	291-G1
IL-3	R&D Systems	203-IL
SCF	R&D Systems	255-SC
EPO	R&D Systems	286-EP
Dexamethasone	Sigma	D4902
Polybrene	Sigma	H-9268
bFGF	R&D Systems	233-FB
Stemolecule Y27632	Stemgent	04-0012
ES Cell Marker Sample Kit	Millipore	SCR002