progenitor cells

(noun)

A biological cell that, like a stem cell, has a tendency to differentiate into a specific type of cell, but is already more specific than a stem cell and is pushed to differentiate into its "target" cell.

Related Terms

Examples of progenitor cells in the following topics:

  • WBC Formation

    • Haematopoietic stem cells (HSCs) reside in the bone marrow and have the unique ability to give rise to all mature blood cell types through differentiation into other progenitor cells.
    • The daughters are the myeloid and lymphoid progenitor cells, which cannot self renew but differentiate into various myeloid leukocytes and lymphocytes respectively.
    • The lymphocyte lineage derives from common lymphoid progenitor cells, which in turn become lymphoblasts before differentiating into T cells, B cells, and NK cells.
    • Myelocytes are an offshoot of common myeloid progenitor cells, which also differentiate into the erythropoietic and magakaryotic progenitors.
    • Megakaryocytes (the cells that produce platelets) and erythrocytes (red blood cells) are not formally considered to be leukocytes, but arise from the common myeloid progenitor cells that produce the other cellular components of blood.

  • Cellular Differentiation

    • Three basic categories of cells make up the mammalian body: germ cells, somatic cells, and stem cells.
    • Pluripotent stem cells undergo further specialization into multipotent progenitor cells that then give rise to functional cells.
    • Examples of stem and progenitor cells include:
    • Epithelial stem cells (progenitor cells) that give rise to the various types of skin cells
    • Muscle satellite cells (progenitor cells) that contribute to differentiated muscle tissue

  • Development of Blood and Blood Vessels

    • Endothelial stem cells (ESCs) are one of three types of stem cells found in bone marrow.
    • These parent stem cells, ESCs, give rise to endothelial progenitor cells (EPCs), which are intermediate stem cells that lose potency.
    • Progenitor stem cells are committed to differentiating along a particular cell developmental pathway.
    • The lineages arising from the EPC and the hematopoietic progenitor cell (HPC) form the blood circulatory system (see ).
    • Hematopoietic stem cells can of course undergo self-renewal, and are multipotent cells that give rise to erythrocytes (red blood cells), megakaryocytes/platelets, mast cells, T-lymphocytes, B-lymphocytes, dendritic cells, natural killer cells, monocyte/macrophage, and granulocytes.

  • Platelet Formation

    • Platelets are small, clear, irregularly-shaped cell fragments produced by larger precursor cells called megakaryocytes.
    • Platelets are continuously produced as a component product of hematopoiesis (blood cell formation).
    • Thrombopoiesis occurs from common myeloid progenitor cells in the bone marrow, which differentiate into promegakaryocytes and then into megakaryocytes.
    • Thrombopoietin stimulates differentiation of myeloid progenitor cells into megakaryocytes and causes the release of platelets.
    • Myeloid progenitor cells differentiate into promegakaryocytes, and megakaryocytes, which release platelets.

  • Medical Uses of Hematopoietic Growth Factors

    • Hemopoetic growth factors regulate the growth, differentiation, and proliferation of progenitor cells in the blood and bone marrow.
    • Hemopoietic growth factors regulate the differentiation and proliferation of particular progenitor cells.
    • Erythropoietin is a sialoglycoprotein hormone produced by peritubular cells of kidney.
    • G-CSF stimulates the production of white blood cells (WBC).
    • G-CSF is also used to increase the number of hematopoietic stem cells in the blood of the donor before collection by leukapheresis for use in hematopoietic stem cell transplantation.

  • Gene Expression in Stem Cells

    • In adult organisms, stem cells and progenitor cells act as a repair system for the body by replenishing adult tissues.
    • Asymmetric division, on the other hand, produces only one stem cell and a progenitor cell with limited self-renewal potential.
    • Progenitors can go through several rounds of cell division themselves before terminally differentiating into a mature cell. .
    • This diagram illustrates stem cell division and differentiation, through the processes of (1) symmetric stem cell division, (2) asymmetric stem cell division, (3) progenitor division, and (4) terminal differentiation.
    • Stem cells are indicated by (A), progenitor cells by (B), and differentiated cells by (C).

  • Development of Blood

    • The other daughters of HSCs, myeloid, and lymphoid progenitor cells, can each commit to any of the alternative differentiation pathways that lead to the production of one or more specific types of blood cells, but cannot self-renew.
    • Erythrocytes are oxygen-carrying red blood cells; they are derived from common myeloid progenitors.
    • Commonly known as white blood cells, they are derived from common lymphoid progenitors.
    • Erythropoietin is required for a myeloid progenitor cell to become an erythrocyte.
    • On the other hand, thrombopoietin makes myeloid progenitor cells differentiate to megakaryocytes, which produce platelets.

  • Embryonic Development

    • The neural tube becomes patterned along the dorsal-ventral axis to establish defined compartments of neural progenitor cells, which will give rise to distinct classes of neurons.
    • These cell types are specified by the secretion of Shh from the notochord (located ventrally to the neural tube), and later from the floor plate cells.
    • The different combinations of expression of these transcription factors along the dorsal-ventral axis of the neural tube are responsible for creating the identity of the neuronal progenitor cells.
    • Five molecularly distinct groups of ventral neurons form from these neuronal progenitor cells in vitro.
    • Studies have shown that neural progenitors can evoke different responses based on the length of exposure to Shh, with a longer exposure time resulting in more ventral cell types.

  • Development of the Immune System

    • This model of lymphopoiesis had the virtue of relative simplicity and agreement with nomenclature and terminology; also, it is essentially valid for the favorite lab animal, the mouse. pHSC pluripotent, self-renewing, hematopoietic stem cells give rise to MPP multipotent progenitors (these give rise to ELP, or PRO, Prolymphocytes); early lymphoid progenitors; and finally to the CLP Common lymphoid progenitor, a cell type fully committed to the lymphoid lineage. pHSC, MPP and ELP cells are not fully committed to the lymphoid lineage because if one is removed to a different location, it may differentiate into non-lymphoid progeny.
    • NK cells Dendritic cells (lymphoid lineage; DC2) Progenitor B cells Pro-B cells => Early Pro (or pre-pre)-B cells => Late Pro (or pre-pre)-B cells Large Pre-B cells => Small Pre-B cells Immature B cells B Cells => (B1 cells; B2 cells) Plasma cells Pro-T cells T-cells.
    • Antigen presenting cells in newborns have a reduced capability to activate T cells.
    • B cells develop early in gestation but are not fully active.
    • There is also some evidence that cell surface receptors on B cells and macrophages may detect sex hormones in the system.

  • Development of the Dual Lymphocyte System

    • Lymphocytes originate from a common progenitor in a process known as hematopoeisis.
    • B cells and T cells are the major types of lymphocytes.
    • Mammalian stem cells differentiate into several kinds of blood cell within the bone marrow.
    • During this process, all lymphocytes originate from a common lymphoid progenitor before differentiating into their distinct lymphocyte types.
    • All lymphocytes originate during this process from a common lymphoid progenitor before differentiating into their distinct lymphocyte types.