Term
| what we do know about the bone marrow microenvironment |
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Definition
| -bone marrow is the site of residence of hematopoietic stem cells, progenitor cells, and precursor cells, and that in a healthy individual only the terminal cells are released into the circulation in bulk. |
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Term
| stem cells introduced into the bloodstread will _______ to the bone marrow, where they encounter specific stromal cells, extracellular matrix (ECM) components, and cytokines that direct their survival, attachment, and differentiation |
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Definition
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Term
| the bone marrow in the adult that is active in hematopoiesis is found in the: |
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Definition
| long bones, iliac crests, and sternum |
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Term
| Bone marrow consists of _____% fat cells and ____% of hematopoietic cells |
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Definition
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Term
| HSCs interact with ______ that line the bone, and _______ that line the vasculature, which includes central arterioles and venules. |
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Definition
osteoblasts
endothelial cells |
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Term
| There are other __________ that produce ECM, cytokines, and adhesion molecules, and macrophages that clean up cellular debris |
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Definition
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Term
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Definition
| provide cell-cell signals through physical contact |
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Term
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Definition
| provide cell-cell signals that help cells home to the bone marrow |
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Term
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Definition
| these eat improperly formed RBC's and extruded RBC nuclei |
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Term
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Definition
| the function of these cells in not well understood inside the bone marrow but they could include energy production or insulation |
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Term
| Do HSC's stay in the bone marrow forever? |
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Definition
NO
HSCs home (reside) in the bone marrow, but are not locked up there; they can go on little trips to other places and then come back to their home |
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Term
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Definition
| defined as the the place that is locally within a few cells/adjacent to a specific location |
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Term
| it is possible that some of the ______ lining the bone are able to tell stem cells that they are running low in number/need to regenerate |
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Definition
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Term
| What are all the different things bone marrow cells interact with? |
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Definition
-with bone
-with vasculature
-with stromal cells
-with each other |
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Term
| another name for microenvironment |
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Definition
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Term
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Definition
| CXCR4 is a HSC receptor and SDF-1 (aka CXCL12) is a factor secreted by osteoblast that sticks onto the ECM. Both factors interact with one another and this is just one of many ways how HSC's and osteoblasts can communicate |
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Term
| Details on how cell-cell interactions cause mobilization and homing for HSC's |
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Definition
1) GCSF mobilizes HSCs by causing release of proteolytic enzymes like elastase, cathepsin G, MMP2 and MMP9 from neutrophils
2) proteolytic enzymes from neutrophils inactivate SDF-1 by cleaving NH2 terminal signal sequence
3) (so HSCs are able to mobilize and freely go into vasculature)
3) after the proteolytic enzyme steps reverse (and SDF-1 is now free) CXCR4 and HSCs are chemoattracted to the highly SDF-1 expressing endosteal/stromal niche.
4) Presentation of ECM-tethered SDF-1 induces transendothelial migration and homing to the HSD niche much like a haptotactic molecular guidance system
(stem cells undergo homing) |
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Term
| what are the different kinds of stromal cells? |
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Definition
-fibroblasts
-endothelial cells
-macrophages
-osteoblasts
-adipocytes |
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Term
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Definition
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Term
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Definition
| these cells express molecules like selectins, and allow stem cells to hit and then rool and egress through vasculature |
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Term
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Definition
| these do receptor-ligand signaling (produce SDF-1) |
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Term
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Definition
-collagen types I,III, and V
-syndecan-1
-perlecan
-fibronectin
-laminin
-biglycan
-decorin |
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Term
| a biopsy lets you see __________ while aspirating lets you see __________ |
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Definition
architecture of cells
individual cells |
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Term
| the 3 ways to look at a cell/try to identify it |
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Definition
1) look at size of cell
2) observe the nucleus
3) observe the cytoplasm |
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Term
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Definition
| are granulocyte precursors |
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Term
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Definition
| the precursor of a neutrophil (has a bent nucleus that hasn't split fully yet) |
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Term
| what we hope to do in future with HSCs |
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Definition
1) to try to get stem cells to leave bone marrow
2) how to grow bone marrow in a lab
3) how to make bone marrow stem cells differentiate along a particular lineage
4) use of bone marrow for regenerative medicine |
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Term
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Definition
| stains blue and has round nucleus (but it is pushed to the side because protein is being made in the center of the cell) |
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