Name: blood cell formation and stem cell migration
Uploaded: 2025-05-22T09:05:39.000Z
Duration: 1 min 21 s
Channel: JoVE

Hematopoiesis&#160; is the process by which different types of blood cells are produced from a single type of cells called hematopoietic stem cells or HSCs.
In adults, hematopoiesis occurs in the bone marrow.&#160; Bone marrow is surrounded by reticular cells, stromal cells, and an intricate web of blood vessels. Hematopoiesis occurs in the spaces between these blood vessels and cell components.
HSCs continuously multiply and self-renew by undergoing asymmetric division. They produce two daughter cells, one of which can self-renew like the parent cell and maintain the HSC pool in the bone marrow.
In contrast, specific molecular factors released in response to tissue injury, growth spurt, or infection help differentiate the second daughter cell into more specialized cells, including the myeloid progenitor cells and the lymphoid progenitor cells.
HSC progenitors can produce all types of blood cells, including red blood cells, lymphocytes, macrophages, and natural killer cells.
Once committed to their specific roles, these blood cells leave the bone marrow and enter the blood vessels to migrate to their site of action.

hematopoiesis

Hematopoiesis

The process of blood cell formation is called hematopoiesis. Hematopoiesis starts early during development, on the seventh day of embryogenesis. This phase of hematopoiesis is called the primitive wave, wherein the extraembryonic yolk sac allows the production of erythroid cells and endothelial cells from a common precursor called hemangioblast. The erythroid cells provide oxygen to support the growth of the rapidly dividing embryo. Hemangioblasts later develop into hematopoietic stem cells or HSCs that can produce all types of blood cells due to their multipotent nature. The HSCs then migrate to the liver during the fetal development stage. In adults, hematopoiesis occurs in the bone marrow of organisms.
Inside the bone marrow, there are two populations of HSCs: dormant or quiescent HSCs and the active or primed HSCs. Dormant HSCs are non-proliferative and remain attached to the inner surface of the bone. On the other hand, active HSCs rapidly proliferate in response to vascular endothelial growth factors and are present in the central marrow region.
HSCs migrate from the bone marrow into the circulating blood to reach the different target tissues. During this migration, HSCs lose cell adherence molecules and chemokine receptor CXCR4. HSCs may return to the bone marrow or reach the target tissue by the process called HSC homing. Homing to bone marrow is essential to regulate HSC homeostasis and maintain the HSC pool through proliferation. During homing, HSCs gain cell adherence molecules and chemokine receptor CXCR4 that help them bind and anchor the target tissue following chemokine gradients.&#160;

The process of blood cell formation is called hematopoiesis. Hematopoiesis starts early during development, on the seventh day of embryogenesis. This ...

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JoVE Core

Cell Biology

Unit 1

A Hierarchical Stem-Cell System: Blood Cell Formation

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KEY TERMS AND CONCEPTS

blood cell formation and stem cell migration

Blood cell formation, or hematopoiesis, begins early in development. Around the seventh day of embryogenesis, the primitive wave starts in the extraembryonic yolk sac. In this early stage, a common precursor called a hemangioblast gives rise to erythroid cells and endothelial cells.

The erythroid cells help carry oxygen and support the fast growth of the embryo. Hemangioblasts later develop into hematopoietic stem cells, or HSCs. These stem cells are multipotent, which means they can produce all types of blood cells.

During fetal development, HSCs move to the liver. In adults, hematopoiesis takes place in the bone marrow. The bone marrow contains two HSC groups: dormant, or quiescent, HSCs and active, or primed, HSCs.

Dormant HSCs do not divide and stay attached to the inner surface of the bone. Active HSCs divide quickly in response to vascular endothelial growth factors. They are found in the central marrow region.

HSCs can leave the bone marrow and enter the circulating blood to reach target tissues. During this movement, they lose cell adhesion molecules and the chemokine receptor CXCR4. They can also return to the bone marrow or reach another tissue through HSC homing.

HSC homing helps regulate HSC homeostasis and maintain the stem cell pool through proliferation. During homing, HSCs regain cell adhesion molecules and CXCR4. These features help them bind and anchor to the target tissue along chemokine gradients.

Blood Cell Formation and Stem Cell Migration

blood-cell-formation-and-stem-cell-migration

overview of the vascular system

Blood and Lymphatic Vessel Layers

The vascular system includes blood vessels and lymphatic vessels. It forms a large network of arteries, capillaries, and veins. In the body, this system is divided into the blood system and the lymphatic system. Blood vessels have three main histological layers. These layers are the tunica intima, tunica media, and tunica adventitia. The tunica intima is the inner layer. It has a single layer of endothelial cells attached to the basal lamina. Beneath that is a connective tissue layer and an...

mechanism of angiogenesis

How New Blood Vessels Grow

How new blood vessels grow through angiogenesis is a key part of early development and tissue repair. Blood vessel formation begins around day 7 of embryonic development. In the extraembryonic yolk sac, mesodermal precursor cells called hemangioblasts multiply and become angioblasts. Angioblasts express vascular endothelial growth factor receptor 2, or VEGFR2. This receptor binds VEGF-A, a proangiogenic factor that helps guide vessel formation. VEGF signaling pushes angioblasts to form a blood...

regulation of angiogenesis and blood supply

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Hypoxia Triggers Angiogenesis Signaling

Hypoxia, or low oxygen, can trigger angiogenesis signaling in tissues that need more blood supply. Rapidly dividing tumors, embryos, and wounded tissues all use more oxygen than usual. As oxygen levels fall, cells switch on a pathway that helps form new blood vessels. A key oxygen sensor in this pathway is hypoxia-inducible factor 1, or HIF1. HIF1 has two parts, an alpha subunit and a beta subunit. Under normal oxygen conditions, HIF1 beta is in the nucleus, while HIF1 alpha stays in the...

Blood cell formation, or hematopoiesis, begins early in development. Around the seventh day of embryogenesis, the primitive wave starts in the extraembryonic yolk sac. In this early stage, a common precursor called a hemangioblast gives rise to erythroid cells and endothelial cells. The erythroid cells help carry oxygen and support the fast growth of the embryo. Hemangioblasts later develop into hematopoietic stem cells, or HSCs. These stem cells are multipotent, which means they can produce...

multipotency of hematopoietic stem cells

HSC Quiescence and Blood Cell Renewal

Hematopoietic stem cells (HSCs) help the body make blood and immune cells. These stem cells are multipotent, which means they can develop into many cell types in the blood system. They usually stay in a quiescent, or resting, state until an outside signal starts them moving toward differentiation. HSCs are grouped into two main populations: long-term repopulating cells (LTRCs) and short-term repopulating cells (STRCs). These groups differ in surface markers, or receptors on the cell surface,...

lineage commitment

Blood Stem Cell Fate Decisions

Blood stem cell fate decisions guide how hematopoietic stem cells become specific blood and immune cells. During commitment, stem cells lose the ability to form all cell types and change irreversibly into a more limited fate. Multipotent hematopoietic stem cells, or HSCs, first differentiate into multipotent hematopoietic progenitor cells, or HPCs. These HPCs express many lineage-specific cytokine receptors. Each receptor binds a specific cytokine, turns on a distinct signaling pathway, and...

erythropoiesis

How Red Blood Cells Are Replenished

Red blood cells, or RBCs, carry oxygen to body tissues and must be replaced after about 120 days. The body keeps this supply steady through erythropoiesis, the process of making new red blood cells. When oxygen levels drop after blood loss or injury, this process increases to restore oxygen delivery. Problems in erythropoiesis can lead to anemia, thalassemia, or polycythemia. Erythropoietin, also called Epo, starts this process. Before birth, the fetal liver makes Epo. After birth,...

differentiation of common myeloid progenitor cells

differentiation-of-common-myeloid-progenitor-cells

CSF Signals That Guide Myeloid Cells

Common myeloid progenitors are blood-forming cells in the bone marrow that can become granulocytes or macrophages. These immune cells protect the body against bacterial, viral, and fungal infections. They leave the bone marrow, travel in the blood, and move into tissues where they help with immune surveillance. These cells do not last long. They survive for only a few days, so the body must keep making them to maintain a strong immune system. During injury or infection, many immune cells are...

regulation of hematopoietic stem cells

How HSC Signals Control Blood Cell Supply

Hematopoietic stem cells, or HSCs, make blood and immune cells through hematopoiesis. These cells are replaced often because many have short life spans. They are also used up during immune surveillance, injury, or infection. This makes blood one of the most regenerative tissues in the body. Hematopoiesis must stay tightly controlled. If too many blood or immune cells are made, the cells can become cancerous or trigger autoimmune responses. Regulation helps HSCs stay quiescent, which means...

key terms and concepts

Follow hematopoiesis from the embryonic yolk sac to adult bone marrow, including HSC states, migration, and homing in blood cell formation.

Blood Cell Formation and Stem Cell Migration | JoVE K12

cell biology

JoVE Core Cell Biology illustrates complex cellular processes in easy-to-understand yet comprehensive animated video lessons. This collection focuses on the essential components and functions of cells, including organelles and membranes, cellular transport, and cell energetics. It is complemented by scientist-in-action videos that demonstrate the application of cell biology in real-world research experiments.

Blood Cell Formation and Stem Cell Migration

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