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Isolation of Blood-vessel-derived Multipotent Precursors from Human Skeletal Muscle
Published on: August 21, 2014
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Isolation of a candidate human hematopoietic stem-cell population
C M Baum1, I L Weissman, A S Tsukamoto
1SyStemix Inc., Palo Alto, CA 94303.
Summary
Researchers discovered rare human fetal bone marrow cells (Thy-1+Lin-CD34+) that are multipotent hematopoietic precursors. These cells are enriched for hematopoietic stem cells, capable of multilineage differentiation and long-term culture.
Area of Science:
- Hematology
- Stem Cell Biology
- Immunology
Background:
- Hematopoietic stem cells (HSCs) are crucial for lifelong blood cell production.
- Identifying and isolating human HSCs is essential for regenerative medicine and transplantation.
- Previous research has focused on various cell surface markers to define HSC populations.
Purpose of the Study:
- To identify and characterize a rare subset of human fetal bone marrow cells with stem cell potential.
- To investigate the multipotent differentiation capacity of these identified cells.
- To evaluate the in vivo engraftment and differentiation capabilities of these precursor cells.
Main Methods:
- Flow cytometry was used to identify and isolate Thy-1+CD34+Lin- cells from human fetal bone marrow.
- Long-term cultures on mouse marrow stromal lines were established to assess clonogenic activity.
- In vitro differentiation assays were performed to evaluate multilineage potential.
- Xenotransplantation into severe combined immunodeficiency (SCID) mice was used to assess in vivo engraftment and differentiation.
Main Results:
- A rare (0.05-0.1%) population of human fetal bone marrow cells expressing Thy-1 and CD34, but lacking lineage markers (Thy-1+CD34+Lin-), was identified.
- This Thy-1+CD34+Lin- subset demonstrated significant clonogenic activity, establishing long-term, multilineage cultures (myelomonocytic, B lymphoid).
- These cells differentiated into T lymphocytes in the fetal thymus of SCID mice and showed successful engraftment, producing donor-derived myeloid and B cells in some cases.
Conclusions:
- The rare human Thy-1+Lin-CD34+ cell population is highly enriched for pluripotent hematopoietic progenitors.
- These findings strongly suggest that this cell population represents candidate hematopoietic stem cells.
- This research provides a refined method for identifying and isolating potential human HSCs for further study and therapeutic applications.
