Figure 1.

Differentiation of hematopoietic stem cells (HSCs). Multipotent and unbiased hematopoietic stem cells (HSCs) are derived from bone marrow. Depending on the niche they occupy in bone marrow and/or expression of certain genes, they become biased in their differentiation potential toward a specific cell lineage, such as osteoclast-biased (Os-Bi), myeloid-biased (My-Bi), platelet biased (Pl-Bi), and lymphoid-biased (Ly-Bi). Some HSCs have balanced differentiation potential and can develop into osteoclast, myeloid, platelet, and lymphoid lineage precursors. Os-Bi HSCs develop into preosteoclasts which, after fusion, create multinucleated osteoclasts. Osteoclasts can also derive from mature monocytes or macrophages. The My-Bi HSCs differentiate into neutrophils, eosinophils, basophils, erythrocytes, and monocytes forming dendritic cells and macrophages. Pl-Bi HSCs develop into megakaryocytes, which subsequently produce platelets. Megakaryocytes can also develop from My-Bi HSCs. Ly-Bi develop into T cells, NK cells, and B cells producing plasma cells.