The regulation of normal and neoplastic hematopoiesis is dependent on microenvironmental cells

Publication date: Available online 27 June 2018 Source:Advances in Biological Regulation Author(s): Kenneth Kaushansky, Huichun Zhan Each day the adult human produces 4 × 1011 red blood cells, 1 × 1011 white blood cells and 1 × 1011 platelets, levels of production which can increase 10–20 fold in times of heightened demand. Hematopoiesis, or the formation of the ten different types of blood and marrow cells, is a complex process involving hematopoietic stem cells (HSCs), cytokine growth factors and cell surface adhesion molecules, and both specific and ubiquitous transcription factors. The marrow micro-environmental niche is defined as the site at which HSCs reside and are nurtured, receiving the signals that lead to their survival, replication and/or differentiation. Using microscopic, biochemical and molecular methods many different cells and the signals responsible for niche function have been identified. Early studies suggested two distinct anatomical sites for the niche, perivascular and periosteal, but the preponderance of evidence now favors the former. Within the “vascular niche” much evidence exists for important contributions by vascular endothelial cells (ECs), CXCL12-abundant reticular (CAR) cells and mesenchymal stromal cells, through their elaboration of chemokines, cytokines and cell surface adhesion molecules. In a series of studies we have found, and will present the evidence that megakaryocytes (MKs), the precursors of blood platelet...
Source: Advances in Biological Regulation - Category: Biology Source Type: research