Related Experiment Video
Updated: Jan 10, 2026
09:03
Extraction of Extracellular Vesicles from Whole Tissue
Published on: February 7, 2019
15.9K
Extracellular Vesicles Define Discrete Nano-Based Niches Within the Human Haematopoietic System.
Isabelle J Grenier-Pleau1, Christopher J Wells1, Samantha M Holmes1
1Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
Journal of Extracellular Vesicles
|November 27, 2025
Summary
Researchers discovered distinct extracellular vesicle (EV)-defined niches within the human hematopoietic system. These unique nanoparticles influence stem cell function based on their location, impacting blood production and immunity.
Area of Science:
- Hematology
- Stem Cell Biology
- Nanomedicine
Background:
- Stem cell niches are complex signaling networks crucial for stem cell function.
- The bone marrow niche harbors hematopoietic stem cells (HSCs), vital for lifelong blood and immune cell production.
- Understanding how niches coordinate intrinsic and extrinsic cellular signals remains a challenge.
Purpose of the Study:
- To identify and characterize unique extracellular vesicle (EV)-defined niches within the human hematopoietic system.
- To investigate the functional impact of these EV-defined niches on hematopoietic stem cells and progenitors.
- To elucidate the role of EVs in regulating stem cell behavior and their location-specific effects.
Main Methods:
- Proteomic analysis of EVs to determine unique signatures.
- Single-vesicle nanoparticle characterization.
- Machine learning techniques for EV classification.
- Stem cell assays to assess functional effects.
- Single-cell transcriptomic analysis to study EV impact on HSCs and progenitors.
Main Results:
- Extracellular vesicles (EVs) form distinct niches within the human hematopoietic system, classifiable by location (blood, bone marrow, trabeculae).
- Location-specific EVs exert differential functional effects on hematopoietic stem cells and progenitors.
- Niche-sourced EVs differentially impact the most primitive human HSCs and progenitors, as shown by single-cell transcriptomics.
Conclusions:
- Extracellular vesicles play a significant role in defining distinct nano-niches within biological systems.
- These EV-defined niches are critical for regulating human immunity and blood production.
- The study reveals a novel function for EVs in demarcating specialized microenvironments for stem cells.
Related Concept Videos
01:36Overview of Exosomes
3.5K
Exosomes are stable, lipid bilayer-enclosed vesicles capable of crossing biological barriers. They can carry a wide range of molecules required for intercellular communication. Once exosomes are released from the cell where they originated, they enter a recipient cell through various pathways such as fusion, receptor-mediated endocytosis, macropinocytosis, and phagocytosis.
Stahl et al. discovered exosomes in 1983, but the exosomes were initially considered waste products released from the...
Stahl et al. discovered exosomes in 1983, but the exosomes were initially considered waste products released from the...
3.5K
01:26Stem Cell Niche
6.2K
The stem cell niche is the dynamic microenvironment where stem cells reside. Inside these niches, the cells may remain undifferentiated, undergo high self-renewal, or become lineage-specific progenitors. Stem cells coexist with other niche cells, such as stromal cells. They also interact closely with the ECM. Cell-cell and cell-matrix communication occur via adhesion molecules or soluble factors that signal the stem cells and determine their fate. Stromal cells also provide survival signals to...
6.2K
01:38Intralumenal Vesicles and Multivesicular Bodies
4.6K
Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
4.6K
01:21Hematopoiesis
8.5K
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...
8.5K
01:33Overview of Secretory Vesicles
9.3K
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
9.3K
01:19Multipotency of Hematopoietic Stem Cells
3.8K
The hematopoietic stem cells or HSCs are multipotent, meaning they can differentiate and give rise to all blood and immune cells. HSCs are maintained in the quiescent stage until an external stimulus initiates their differentiation. The multipotent HSCs exist as two heterogeneous populations, long-term repopulating cells (LTRC) and short-term repopulating cells (STRC). The two HSC populations have different surface markers or receptors and are classified based on quiescence and long-term...
3.8K