The key difference between hematopoietic stem cells and progenitor cells is that hematopoietic stem cells have the ability to differentiate into different types of cells while progenitor cells are more specific and they differentiate into target cells.
Stem cells have the ability to change into many different types of cells and grow definitely in the human body. Hematopoietic stem cells are immature cells that develop into all types of blood cells. Progenitor cells are descendants of stem cells that further differentiate into specialized cell types.
CONTENTS
1. Overview and Key Difference
2. What are Hematopoietic Stem Cells
3. What are Progenitor Cells
4. Similarities – Hematopoietic Stem Cells and Progenitor Cells
5. Hematopoietic Stem Cells vs Progenitor Cells in Tabular Form
6. Summary – Hematopoietic Stem Cells vs Progenitor Cells
What are Hematopoietic Stem Cells?
Hematopoietic stem cells (HSCs) are immature cells found in the peripheral blood and bone marrow. They have the ability to give rise to all types of blood cells, including white blood cells, red blood cells, and platelets. This process is called hematopoiesis. The initial HSCs in vertebrates arise from the ventral endothelial wall of the embryonic aorta within the aorta-gonad-mesonephros region. Later, HSCs are also found in the yolk sac, embryonic head, placenta, and fetal liver. The hematopoiesis process in adults takes place in the red bone marrow. Thus, in adults, HSCs are found in bone marrow, especially in the pelvis, sternum, and femur. HSCs develop into different types of blood cells in lines called myeloid and lymphoid, which are involved in dendritic cells formation.
Figure 01: Hematopoietic Stem Cells
Myeloid cells include macrophages, monocytes, neutrophils, eosinophils, basophils, and megakaryocytes, and platelets. Lymphoid cells include T cells, B cells, innate lymphoid cells, and natural killer cells. The shape of HSCs usually resembles lymphocytes. They are round, non-adherent, and consist of a round nucleus and low cytoplasm to nucleus ratio. HSCs cannot be identified through a microscope since they cannot be isolated as a pure population. HSCs are identified using flow cytometry. Here, a combination of different cell surface markers is used to separate the rare HSCs.
What are Progenitor Cells?
Progenitor cells are the cells that originate from stem cells and further differentiate to create specialized cell types. Progenitor cells are capable of differentiating into cells that belong to the same tissue or organ of each progenitor cell. Some cells differentiate into targeted cells, while other cells have the ability to differentiate into more than one type of cell. Progenitor cells are an intermediary step in the development of mature cells in tissues, organs, blood, and the central nervous system. In the central nervous system of humans, there are three types of fully differentiated cells known as neurons, astrocytes, and oligodendrocytes. These cells evolve from the differentiation of neural progenitor cells (NPCs).
Figure 02: Progenitor Cells
Hematopoietic progenitor cells (HPCs) are also intermediates in the development of blood cells. Hematopoietic stem cells differentiate into multipotent progenitor cells. These multipotent progenitor cells differentiate into either common myeloid progenitor (CMP) or common lymphoid progenitor cells (CLP). Both CMPs and CLPs are types of oligopotent progenitor cells. These cells become mature blood cells along cell lines. The primary function of progenitor cells is to replace damaged cells. Therefore, progenitor cells are necessary for repairs and to maintain tissues after an injury. They also play a role in embryonic development.
What are the Similarities Between Hematopoietic Stem Cells and Progenitor Cells?
- Both types of cells are found in multicellular organisms.
- They play a role in cell development and differentiation.
- Both cells have common applications in various cell-based therapies such as tissue regeneration and transplantation.
- Both undergo replication.
- These cell types are used in cell culture studies to analyze cellular responses in different clinical and physiological settings.
What is the Difference Between Hematopoietic Stem Cells and Progenitor Cells?
Hematopoietic stem cells have the ability to change into different types of cells and grow indefinitely. They can create new tissues and even whole organs from a few stem cells. On the other hand, progenitor cells are more specific than hematopoietic stem cells and can differentiate into target cells. Thus, this is the key difference between hematopoietic stem cells and progenitor cells. Moreover, based on how they replicate, HPSCs show an indefinite replication while progenitor cells show a definite replication pattern.
The below infographic presents the differences between hematopoietic stem cells and progenitor cells in tabular form for side by side comparison.
Summary – Hematopoietic Stem Cells vs Progenitor Cells
Hematopoietic stem cells are immature cells found in the peripheral blood and bone marrow. They have the ability to give rise to all types of blood cells, such as white blood cells, red blood cells, and platelets, etc., through a process called hematopoiesis. Progenitor cells originate from stem cells, and they can further differentiate to create specialized cell types. They have the ability to differentiate into cells that belong to the same tissue or organ of each progenitor cell. Both HSCs and progenitor cells have applications in various cell-based therapies such as tissue regeneration and transplantation. So, this summarizes the difference between hematopoietic stem cells and progenitor cells.
Reference:
1. Ng, A., & Alexander, W. “Haematopoietic Stem Cells: Past, present and future.” Nature.
2. “What are progenitor cells? exploring neural, myeloid and hematopoietic progenitor cells.” Technology Network.
Image Courtesy:
1. “Hematopoiesis simple” By A. Rad and Mikael Häggström, (CC BY-SA 3.0) via Commons Wikimedia
2. “STEM CELLS AND PROGENITOR CELLS” By Acn20 – Own work (CC BY-SA 3.0) via Commons Wikimedia