Harvey Chapter 3 Hematopoiesis (with Schalm's) AKG Flashcards
Primitive hematopoiesis - name the locations in where it occurs before it reaches the bone marrow and lymphoid organs.
- Starts in the yolk sac (outside of the body of embryo)
- Then moves within aorta-gonad-mesonephros (AGM) region of the embryo
- Shift to liver and spleen mid-gestation
- Then to bone marrow and lymphoid organs
The HSCs and associated endothelial cells (endothelium of yolk sac and dorsal aorta) are produced by common embryonic stem cells known as _____. These cells express what surface markers?
Hemangioblasts: VEGFR-2, CD34, CD133
Major hematopoietic organs in…
Bird:
Reptiles:
Amphibians:
Fish:
Bird: bone marrow
Reptiles: bone marrow +/- spleen
Amphibians: kidney, liver, spleen +/- bone marrow
Fish: kidney and/or spleen
The particular stromal cells that support the endothelium of the venous sinuses in the bone marrow are termed _______.
Adventitial stromal cells
A scanning electron micrograph of the cut surface of bone marrow showing a system of vascular sinuses originating at the periphery of the marrow (right side of field) and draining into a large vein (upper left corner). The large vein has several apertures in its wall, representing tributary venous sinuses. Hematopoietic tissue lies between the vascular sinuses.
A scanning electron micrograph from the extravascular space in rat bone marrow. Spherical hematopoietic cells are shown developing in close association with marrow stromal cells and their cytoplasmic processes.
Granulopoiesis occurs primarily on the surface of _______.
stromal cells
In addition to hematopoietic cells and developing blood cells, there are a number of accessory cells involved in regulating hematopoieis that reside within the extravascular space of mammalian bone marrow. What are these accessory cells?
Macrophages
NK cells
Mature lymphocytes
Hematopoietic stem cells (HSC) exhibit long-term self-renewal and differentiation. How often do they replicate?
Once every 8-10 weeks
______ are cells that form colonies in the bone marrow culture like HSCs, but do not have long-term self-renewal capacities.
Hematopoietic progenitor cells (HPCs)
HSCs and HPCs cannot be distinguished from mature lymphocytes morphologically. What surface marker can be used to label HSCs and HPCs that would differentiat them from from lymphocytes?
CD34 - some HSCs lack CD34 though (possibly primitive non-active/quiescent HSCs are negative CD34, and CD34 may be used to assess degree of activation); CD34 is also present on nonhematopoietic stem cells and vascular endothelial cells.
Stem cell antigen 1 (SCA-1)
c-kit (c-kit = receptor for SCF)
CD133
Frequency of HSCs in marrow is < _____% in mice and < _____% in cats.
Are HPCs present in higher or lower concentrations?
< .01% in mice
<.0001% in cats
HPCs >>> HSCs (< 2% of all nucleated bone marrow cells in adult dogs are CD34+, but up to 18% of CD34+ cells have been reported in neonatal pups)
Which cells are more numerous in the marrow: HSCs or HPCs?
HPCs
WHen measured in an in vitro cell culture assay, HPCs are referred to as _____. HPCs that rapidly proliferate, retain their ability to migrate, and form multiple subcolonies around a larger central colony in culture are called _______.
Colony-forming units (CFUs)
Burst-forming units (BFUs)
In mammals, all blood cells are produced in the ____ space of the bone marrow. In birds however, only leukocytes are produced in the ______ space of the bone marrow. Erythrocytes and thrombocytes are produced within the ____ space of the marrow.
Mammals - extravascular space
Birds - leukocytes in extravascular space; erythrocytes and thrombocytes in the vascular space
Marrow stromal cells, adipocytes, osteoblasts, chondrocytes, fibroblasts, and myoblasts all come from which stem cells?
Mesenchymal stem cells
List different stem cell markers:
Surface molecules
Transcription Factors
Surface molecules: CD34, stem cell antigen-1 (SCA-1), c-kit, CD133
Transcription factors: Oct4, Nanog, Sox-2
Dye efflux (flow cytometry)
List the appropriate chemokine that:
- Produced by marrow endothelial cells and stromal cells
- Forms a gradient to promote migration of HSCs/HPCs from blood to bone marrow. These cells express its receptor CXCR4.
- Promotes expression of CXCR4 and other adhesion molecules on the surface of HSCs/HPCs
- Induces transendothelial migration
CXCL12 = SDF-1 (stromal cell derived factor 1)
Homing of HSC HPCs to the marrow
Which molecules are:
- membrane-spanning, sugar-binding glycoproteins
- Bind to glycosylated ligands on HSCs/HPCs
- Promote loose, rolling-type adhesion b/w HSCs/HPCs and endothelial cells in blood
P- and E-selectin molecules
Homing of HSC/HPCs to the marrow
Which molecules:
- Are expressed on the surface of migrating cells
- Bind to counter receptors VCAM-1 on endothelial cells
- Are responsible for tight adhesion
Integrins –> α₄β₁-integrin (very late antigen-4, VLA-4)
In steady state conditions, quiescent HSCs can be found near _______, and osteoblasts help regulate their number. More active HSCs and HPCs can be found near ______ and likely have a homeostatic role during steady-state conditions.
endosteal and trabecular bone
vascular sinuses
- Erythroid cells develop around ______
- Megakaryocytes form adjacent to _______
- Granulocyte develop adjacent to ______
- macrophages
- sinusoidal endothelial cells
- Adventitial stromal cells (away from vascular sinuses)
Which two collagen types are produced by stromal cells in BM to provide a surface that HSCs and HPCs can adhere to:
Collagen types I and IV
List the three early-acting hematopoietic growth factors (HGFs) that are involved with triggering dormant (G0) primitive HSCs to begin cycling:
- Stem cell factor (SCF)
- fms-like tyrosine kinase ligand (Flt3L)
- TPO
List three intermediate-acting HGFs that have broad specificity and support proliferation of multipotent HPCs:
- IL-3 (multi-CSF)
- GM-CSF
- IL-4
List five late-acting HGFs that have restricted specificity, and have the most potent effects on committed progenitor cells and later stages of development when cell lines can be recognized morphologically.
- M-CSF (macrophage-CSF)
- G-CSF
- EPO
- TPO
- IL-5
Which HGF is considered an early and late-acting HGF that sitmualtes platelet production and maintains population of HSCs in osteoblastic niche.
TPO
Primitive RBCs enter blood as nucleated cells. In mammals, enucleation can eventually occur in circulating. The extruded nuclei circulate for a shor ttime and are surrounded by a small amount of cytoplasm. They have been called _____.
Pyrenocytes
Embryonal hemoglobin has a ___ oxygen affinity.
high
The earliest erythroid progenitor is called the _____ , which differentiates into the _____. The first morphologically recognizable erythroid cell is the _____.
Burst-forming unit erythrocyte (BFU-E)
Colony-forming unit erythrocyte (CFU-E)
Rubriblast
Primary growth factor involved in proliferation and differentiation of CFU-Es into rubriblasts
EPO
- Early and late stages of erythroid development occur with intimate membrane apposition to central macrophages in “erythroid islands.”
- Direct contact with macrophages enhances proliferation of erythroid precursors under basal conditions
- Macrophages may also produce EPO - positive growth factor
- Macrophages may also produce negative factors, mostly associated with inflammation- list these.
- IL-1
- TNF-a
- TGF-b
- IFN-alpha, IFN-beta, IFN-gamma
List the nutrients required for erythropoiesis
- Amino acids and essential fatty acids
- Copper (in form of ceruloplasm)
- Vitamin B6 (pyridoxine)
- Tetrahydrofolic acid (active form of folic acid - B9)
- B12
In erythroid cells, what gives the cells a blue color vs red color when using Romanowsky-type stain?
Blue - ribosomes/polyribosomes
Red - hemoglobin
More red - means losing ribosomes and gaining more hemoglobin
What is the main type of reticulocyte in cats compared to dogs?
Reticulocytes are generally not released from bone marrow of non-anemic cats until they mature to punctate-type reticulocytes. Consequently few to no aggregate reticulocytes (< 0.4%) but up to 10% punctate reticulocytes are found in blood from normal adult cats. The punctate reticulocyte takes 10-12 days to mature. If they form a regenerative response, aggregate reticulcoytes will get released, but will only last about a day before they mature into punctate reticulocytes. Punctate reticulocytes do NOT appear as polychromatophils when stained with Wright-Giemsa stain. Canines release immature aggregate-type reticulocytes that quickly mature into adult RBCs within 24 hours and the punctate reticulocytes are short lived.
Inhibitors of erythropoiesis:
- TGF-beta
- TNF-alpha
- IFN-y
- IL-6 (enhances megakaryopoiesis and granulopoiesis)
- TNF-related apoptosis ligand (TRAIL)
EPO synthesis in adult mammals occurs primarily where?
What is an extrarenal source of EPO in adults that is the major site of EPO production in mammalian fetus?
- Within peritubular interstitial cells located within the inner cortex and outer medulla of the kidney.
- Liver
*macrophages and EP cells can also produce EPO in BM
Other hormones can enhance growth of EP cells in vitro:
- Androgens
- Glucocorticoid hormones
- GH
- Insulin and insulin-like growth factors
- Thyroid hormone (T3)
EPO has roles outside of hematopoiesis:
- promote proliferation and migration of endothelial cells
- enhance neovascularization
- stimulate production of modulators of vascular tone
- exert cardioprotective and neuroprotective effects
Congenital Dyserythropoiesis - Poodle macrocytosis
- Toys and Minis
- not anemic, no reticulocytosis
- marked macrocytosis (85-105 fL), +/- metarubricytosis w/ nuclear-cytoplasmic asynchrony, HJBs (large + multiple)
- BM: looks like VB12 deficiency
- nuclear bridging!
Inherited selective malabsorption of cobalamin
- Giant schnauzers, Border Collies, Beagle, cat
- GI absorption, essential cofactor for methylmalonic-CoA mutase + methionine synthase → tetrahydrahydrofolate which is essential cofactor for NA synthesis
- inhibition of nuclear maturation → megaloblastosis, neutropenia, hyperseg neuts
- normocytic, normochromic w/ increased RDW
- lack of receptor for intrinsic factor-cobalamin complex = cubilin
- chronic NRA, acanthocytosis, increased RDW
- Dx: serum cobalamin, methylmaolnic acid, total homocysteine
This is a fatal condition in polled hereford calves. Affected calves have macrocytic normochromic anemia with mild reticulocytosis.
Congenital dyserythropoiesis with dyskeratosis
Congenital dyserythropoiesis, polymyopathy, and cardiac disease in ________ is characterized by moderate anemia with spherocytes, schistocytes, dacryocytes, codocytes, and vacuolated RBCs seen in blood smears
English springer spaniels
Which myeloid stages are capable of mitosis?
Which stage produces primary (reddish purple) cytoplasmic granules?
Which stage produces secondary (specific) granules?
Myeloblast
Promyelocytes - produce primary granules
Myelocytes - produce secondary (specific granules)
Which myeloid stages fall under the post-mitotic (matruation and storage pool) pool?
Metamyelocytes
Bands
Segmented neutrophils
What are the three most improtant cytokines in the production of neutrophils?
IL-3
GM-CSF
G-CSF
WHich cytokine promotes granulopoiesis and thrombopoiesis during inflammation?
IL-6
Which cytokine promotes terminal maturation of eosinophils? Which lymphocytes produce this cytokine?
IL-5; Th2
IL-3, GM-CSF, and IL-5 inhibit _______
IL-12 and IFN-y inhibit ______
IL-3, GM-CSF, and IL-5 inhibit eosinophil apoptosis (POSITIVE)
IL-12 and IFN-y inhibit eosinophil production (NEGATIVE)
Maturation of mast cells occurs where?
in TISSUES (not bone marrow); mast cells can also proliferate locally
What is the major growth and differentiation factor for mast cells?
It takes _____ (more/less) time to make monocytes than granulocytes.
less; and many monocytes are not stored in the marrow
Not all macrophages and dendritic cells originate from monocytes in steady state conditions because these cells are capable of self-replication. What are examples in skin and CNS?
Langerhans cells (epidermal dendritic cells)
Microglia (macrophages in CNS)
IL-3, GM-CSF, M-CSF and IL-___ are involved in monocyte production.
IL-34
Exposure of ______ promotes development of M1-like macrophages.
Exposure of _____ promotes development of M2-like macrophages.
M-CSF + IFN-y –> M1
M-CSF + IL4 –> M2
GM-CSF + IL4 + TNF-a produce _______ dendritic cells
‘inflammatory’ or ‘TNF-a and inducible iNOS-producing’ dendritic cells
Monocyte progenitors + M-CSF + ______ –> osteoclasts
What inhibits osteoclast formation?
- RANKL
- IL3 + GM-CSF inhibits osteoclast formation
Development of B and T lymphocyte progenitor cells is antigen _____.
INDEPENDENT
Which IL cytokine is a big positive-growth factor for B-cells?
IL-7
TGF-B, IFN-a, IFN-B, and IFN-y are ____ of B-cell lymphopoiesis.
inhibitors
Plasma cells are dervied from B-cells. They can only be formed in lymphoid organs. T/F
False - B-cells can differentiate into plasmablasts and plasmablasts can develop into plasma cells in lymphiod tissue, as well as peripheral tissues or bone marrow
______ attracts plasmablasts to bone marrow. and _____ + _____ promote plasma cell development by preventing apoptosis.
SDF-1; SDF-1 and IL-6
T-cell progenitors are made in the ____ and mature in the _____.
bone marrow; thymus
Most NK cells are produced, proliferate, and mature in the _____.
bone marrow
What are hte positive growth facotrs for NK cells?
SCF; IL-2; IL-7; and IL-15
Megakaryoblasts undergo ____ (nuclear reduplication without cell divisions).
endomitosis
Positive growth factor for megakaryocytes is SDF-1 and ____.
FGF-4
*promote binding and localization of megakaryocytic progenitors in vascular niche (via adhesion molecules VCAM-1 and a4B1 integrin)
Do non-mammalian species have megakaryocytes?
No - thrombocytes are nucleated and are produced via mitosis of precursors
____ is the key stimulator of platelet production. The major site of its production is _____.
TPO - endothelial cells of the liver
Platelets and megakaryocytes have ____ receptors to provide NEGATIVE-feedback by binding, internalizing and degarding ____.
TPO (c-Mpl receptors)
Blood [TPO] is _____ in thrombocytopenia resulting from megakaryocytic hypoplasia.
Blood [TPO] is _____ with ongoing immune-mediated thrombocytopenia, becuase megakaryocytes are generally increased int he marrow and rapid platelet turnover is ocurring.
High
Low
____ increases production of TPO by the liver and can contribute to thromobocytosis in some inflammatory conditions.
IL-6
Platelet factor 4; TGF-B; IL-4; and TNF-alpha are ____ of megakaryocyte production.
inhibitors
IN health, young platelets have large amounts of ____ on their surface, but become progressively ____ as they age. These aged platelets bind to hepatic ____ receptor, and are ingested by hepatocytes.
sialic acid
desilaylated
AMR receptor
In ITP, auto-antibodies against ___ or ____ induce platelet phagocytosis and destruction by ____ macrophages. This is why ____ can be a component of ITP treatment in humans.
This is a transcription factor that binds 3’ flanking region of EPO gene and stimulates EPO production. It is constitutively produced, but degraded by an oxygen dependent protease - so accumulates during hypoxia.
HIF-1
(hypoxia inducible factor)
Glucocorticoids ___ ertyhroid progenitor proliferation and ____ differentiation.
stimulate; inhibit
This is an anti-apoptotic protein that prevents apoptosis of hemoglobinizing rubricytes.
Bcl-xL
This molecule is associated with EPO receptor and is responible for down stream signaling in erythroid progenitors via recruitment of STAT5
JACK 2
What is the megakaryocyte and platelet receptor for TPO?
MPL
What is the hepatocyte receptor for desialylated (aged) platelets?
AMR
