Thrombopoietin (TPO)
Quick Facts
| Feature | Information |
|---|---|
| Full Name | Thrombopoietin |
| Abbreviation | TPO |
| Alternative Name | Megakaryocyte Growth and Development Factor (MGDF) |
| Molecule Type | Recombinant Cytokine / Growth Factor |
| Family | Hematopoietic Cytokine Family |
| Molecular Weight | ~70-95 kDa (Glycosylation dependent) |
| Primary Receptor | c-Mpl (MPL/CD110) |
| Typical Working Concentration | 10-100 ng/mL |
| Common Stock Concentration | 10-100 μg/mL |
Overview
Thrombopoietin (TPO) is the principal cytokine regulating the survival, self-renewal, and differentiation of hematopoietic stem cells (HSCs) and the development of megakaryocytes and platelets. Although originally identified for its role in thrombopoiesis, TPO is now recognized as one of the most important growth factors for maintaining primitive hematopoietic stem cells in vitro.
In cell culture, TPO is widely used for hematopoietic stem cell expansion, megakaryocyte differentiation, platelet production, and stem cell research. It is frequently combined with Stem Cell Factor (SCF), FLT3 Ligand (FLT3L), and interleukins in serum-free hematopoietic culture systems.
Biological Function
TPO regulates several biological processes, including:
- Maintains hematopoietic stem cell self-renewal
- Promotes stem cell survival
- Stimulates megakaryocyte proliferation
- Induces megakaryocyte maturation
- Supports platelet production
- Inhibits apoptosis in hematopoietic cells
- Enhances progenitor cell expansion
Mechanism of Action
TPO binds to the c-Mpl (MPL/CD110) receptor expressed on hematopoietic stem cells, megakaryocyte progenitors, and mature megakaryocytes.
Ligand binding induces receptor dimerization and activation of multiple intracellular signaling pathways, including:
- JAK2-STAT pathway
- PI3K-AKT pathway
- MAPK/ERK pathway
- SRC family kinase pathways
These pathways regulate stem cell maintenance, proliferation, survival, and megakaryocyte differentiation.
Common Applications
TPO is widely used for:
- Hematopoietic stem cell culture
- CD34⁺ cell expansion
- Megakaryocyte differentiation
- Platelet production protocols
- Bone marrow cell culture
- Stem cell transplantation research
- Gene editing of hematopoietic stem cells
- Regenerative medicine
Cell Types Commonly Supplemented with TPO
| Cell Type | Typical Application |
|---|---|
| Hematopoietic Stem Cells (HSCs) | Maintenance and expansion |
| CD34⁺ Cells | Ex vivo expansion |
| Hematopoietic Progenitor Cells | Survival |
| Megakaryocyte Progenitors | Differentiation |
| Mature Megakaryocytes | Platelet production |
| Human iPSCs | Hematopoietic differentiation |
| Human ESCs | Blood lineage differentiation |
| Bone Marrow Cells | Stem cell studies |
TPO is rarely used alone and is typically combined with additional hematopoietic cytokines.
Typical Working Concentrations
| Application | Typical Concentration |
|---|---|
| Hematopoietic Stem Cells | 20-100 ng/mL |
| CD34⁺ Cell Expansion | 50-100 ng/mL |
| Megakaryocyte Differentiation | 25-100 ng/mL |
| Platelet Production | 50-100 ng/mL |
Advantages
- Essential regulator of hematopoietic stem cell maintenance
- Promotes megakaryocyte maturation and platelet production
- Supports long-term HSC survival
- Widely used in stem cell and regenerative medicine research
- Compatible with serum-free hematopoietic media
- Well-characterized c-Mpl signaling pathway
Limitations
- Activity depends on c-Mpl receptor expression
- Rarely effective as a single cytokine
- Sensitive to repeated freeze-thaw cycles
- Relatively expensive
- Requires optimization with additional cytokines for most applications
Related Growth Factors
Frequently combined with:
- Stem Cell Factor (SCF)
- Fms-like Tyrosine Kinase 3 Ligand (FLT3L)
- Interleukin-3 (IL-3)
- Interleukin-6 (IL-6)
- Granulocyte Colony-Stimulating Factor (G-CSF)
- Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF)
- Erythropoietin (EPO)
See Also
- Growth Factor Handling and Storage Guide
- Hematopoietic Stem Cell Culture
- CD34⁺ Cell Expansion
- Megakaryocyte Differentiation
- Platelet Production
- c-Mpl Signaling
Key Takeaways
- TPO is the primary cytokine regulating hematopoietic stem cell maintenance and megakaryocyte development.
- It signals through the c-Mpl (MPL/CD110) receptor, activating JAK2-STAT, PI3K-AKT, MAPK/ERK, and SRC signaling pathways.
- TPO is indispensable for hematopoietic stem cell expansion, megakaryocyte differentiation, and platelet production protocols.
- It is commonly combined with SCF, FLT3L, IL-3, and IL-6 in serum-free hematopoietic culture systems.
- Typical working concentrations range from 10-100 ng/mL, depending on the application.
References
- Kaushansky K. Blood (1995).
- Kaushansky K. New England Journal of Medicine (1998).
- Freshney RI. Culture of Animal Cells: A Manual of Basic Technique and Specialized Applications.
- Thermo Fisher Scientific. Recombinant Human Thrombopoietin Product Information.
- PeproTech. Recombinant Human Thrombopoietin Product Datasheet.