Hematopoiesis BHS Liège 27/1/2012 Dr Sonet Anne UCL Mont-Godinne
Hematopoiesis: definition = all the phenomenons to produce blood cells Leukocytes = White Blood Cells Polynuclear = Granulocytes Platelet Erythrocyte Neutrophil Eosinophil Basophil Monocyte Lymphocyte Plasma Coagulation Adapted from F.Galland Oxygen Transportation Immune system: phagocytosis, degranulation, bactericidy WBC, Plt RBC
Hematopoiesis: definition All blood cells arise from a single cell type: The hematopoietic stem cell (HSC), located in the bone marrow. Hematopoiesis Hematopoietic stem cell (HSC) Mature Blood cells
The 4 hematopoietic compartments 1. Stem cells Multipotent 2. Progenitors CS engaged in a cellular lineage 3. Precursors Dividing and maturating 4. Mature blood cells Functional cells, in the blood
The 4 hematopoietic compartments 1. Stem cells Non morphologically identifiable Non recognizable at microscope Very rare (0.01-0.05%), mainly quiescent (phase 0) MULTIPOTENT SELF-RENEWAL DIFFERENTIATION CD34 Adapted from Pascale CORNILLET-LEFEBVRE and Philippe NGUYEN; Laboratoire d Hématologie, CHU REIMS Surface markers: example CD34 Resistant to: cytotoxics, irradiation, congelation (-196 C)
Hematopoietic stem cell: Properties MULTIPOTENT: can give rise to all differentiated blood cells DIFFERENTIATION: able to transform, to mature Erythrocytes T, B, NK lymphocytes Platelets Neutro-,Eosino-,Basophils Monocytes/macrophages Mast cells
Hematopoietic stem cell: Properties SELF-RENEWAL: HSC will choose 1 of the 2 pathways: self-renewal (maintains primitive state) or differentiation (driven toward a more mature state) 1 «mother» cell 1 «mother» cell «Unbalanced» mitosis 1 «child» cell + mature 1 identical Cell 2 kinds of progeny Mitosis 1 kind of progeny: 2 «child» cells, more mature than mother
2 blood lineages: Myeloid or Lymphoid CFU-GEMM MYELOID Lineage CFU-GM CFU-L LYMPHOID Lineage 2. Progenitors Multipotent Limited capacity of self-renewal Cell engaged in a cellular lineage Rapid cycling, expansion Non recognizable at microscope Are named by the types of colonies they give rise to: CFU-GEMM: Granulocyte, Erythroid, Monocyte, Megakaryocyte CFU-GM: Granulocyte, Monocyte CFU-L: Colony Forming Unit - Lymphoid Plt Rbc WBc Lymphocytes B, T, NK
The 4 hematopoietic compartments MYELOID lineage LYMPHOID lineage From precursor to mature cell: 3 to 5 mitosis --> 1 precursor can give birth to 32 children cells (exception: platelets) 3. Precursors Do not self-renew Blast cells committed to unilinear differentiation Still replicate until near terminal differentiation Morphology recognizable at microscope Progeny increasingly acquire specific functions and cell surface markers
Membrane surface markers CD34 During differenciation, maturing cells progressively express «markers» at cell surface (CD): CD34, CD33, CD38, HLA-DR, CD13 CD61 CD51 CD41 CD42 MYELOID Lineage CD71 CD35 CD44 CD55 CD147 glycophorines CD35 CD13 CD33 CD14 CD11 CD33 CD16 CD13 CD35 T receptor CD2 CD3 CD4 CD8 TCR B receptor LYMPHOID lineage CD16 CD56 CD19 CD20 CD10 Chaîne m = B Lymphocyte = T Lymphocyte Those antigens can be recognized by antibodies (Immunohistochemistry, Flow cytometry) Some are specific = =
The 4 hematopoietic compartments Blood vessel Platelets Erythrocytes Monocytes/macrophages Neutrophils,Eosinophils, Basophils T, B, NK lymphocytes Mast cells, 4. Blood mature cells Functional cells, move in the blood
Hematopoiesis: a dynamic process Continuous and prodigious production in the marrow and lymphoid tissues : ~10 13 cells per day! RBC: 2 millions/second! Plts: 150. 10 9 /day Neutros: 100. 10 9 /day Balance between production and cell death Blood vessel Cell death: cells have a limited duration of life: WBC: ~2 to 6 days RBC: ~120 days Numeration: Plt: ~7 to 10 days WBC: 7.000 /µlitre +/- 3.000 RBC: 4.5 (F) - 5 (M) x 10 6 /µlitre +/- 500.000 Plt: 150 450.000 /µlitre
Differences between HSC and blood cells Self-renewal Proliferation From HSC to Blood Cells: - height - nucleo-cytoplasmic rapport - nucleoli disparition - chromatine condensation - modifications of: nucleus, membrane, cytoplasme, Differentiation Expression of new sets of genes (CD) Maturation
ERYTHROPOIESIS Division +
ERYTHROPOIESIS +++ Erythropoietin BONE MARROW BLOOD 1 16 5 to 7 days Division + Maturation = Différenciation
GRANULOPOIESIS +++ G-CSF Monocytes Eosinophils Basophils example: Neutrophils ~14 days Division + Maturation = Différenciation 7.5 days 6.5 days
THROMBOPOIESIS E N D O M I T O S I S TPO, IL3, SCF Quiescent Activated Megakaryocyte
LYMPHOPOIESIS Multipotent stem cells Graphic accessed http://www.tulane.edu/~dmsander/www/mbchb/anatomy.gif, 2004. MYELOID Bone Marrow LYMPHOID Bone Marrow Blood THYMUS 2ary lymphoid tissue: Lymph nodes, Spleen,Tonsils,Peyer s Patches, Subendo- & epithelial foci T Lymphocytes Blood B Lymphocytes
LYMPHOPOIESIS: B-cells B O N E M A R R O W B-Precursor Immature B-Cell Mature B-Cell Dendritic cell T Centroblasts Centroblatss T Plasmocytes Centrocytes Follicle B-Lymphocytes B Memory cells B L O O D Secondary lymphoid tissue: Lymph node Germinative center
Hematopoiesis: foetus de Wolf et Pander Endothelial cells Primitive pluripotent blood cells
Hematopoiesis: adult Bone marrow cell mass: 4-5% body weight BM limited to axial squeleton: Cranium 20% Thorax 30% (sternum, ribs, vertebrae,clavicules,omoplates) Lombar Rachis and pelvic ceinture 40% (sacrum, iliac bones) Femur 10% Sites of marrow examination
HSC: Micro-environment: «niche» From NIH Stem cell Printer at http://www.nih.gov/news/stemcell/scireport.htm
Hematopoiesis: a regulated process In the micro-environment, HSC find: Extracellular Matrix Stromal cells: - endothelial cells - fibroblasts - adipocytes - macrophages Stem cell CXCR-4 SDF-1 Vitamins and oligoelements: B12, B9, Fe,.. Hormons Cytokines and growth factors Adapted from Pascale CORNILLET-LEFEBVRE and Philippe NGUYEN; Laboratoire d Hématologie, CHU REIMS In the micro-environment, HSC communicates with other cells by intercellular contacts, adhesion molecules, Exple 1: SDF-1 and CXCR-4 (Plerixafor target) Exple 2: VLA-4 and VCAM-1: adhesion molecules
Malignant hemopathies Bone marrow: «niche» for stem cells Genetic multipotent program of stem cell 2 Differentiation and division: multi step process Google: derochebelle.qc.ca 2 1 Blood mature cells: - O2 transport - Immunity - Coagulation
Malignant hemopathies Ex: t(9;22) Ex: t(15,17) Ex: JAK2 mutation Acute Myeloid Leukemia (Promyelocytic) Stop differentiation Vaquez CML or Essential Thrombocytosis No mature cells
Hematopoiesis: conclusions All blood cells arise from a single cell type: The hematopoietic stem cell (HSC), located in the bone marrow. Hematopoiesis Hematopoietic stem cell (HSC) Production of blood cells is achieved via differentiation of primitive pluripotent stem cells through a series of cell divisions and maturation (usually 3 to 5 cell cycles for terminal differentiation). This production is continuous and highly regulated to maintain circulating cell numbers within relatively constant levels and to respond rapidly to conditions requiring extra cells. Mature Blood cells
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