Why are hematopoietic stem cells so ‘sexy’? on a search for developmental explanation

• Published in: Leukemia 2017-08, Vol.31 (8), p.1671-1677
• Main Author: Ratajczak, M Z
• Format: Article
• Language: English
• Subjects: 13/100; 631/532/1542; 96/21; 96/63; Androgens; Animals; Aorta; Aplasia; Bioaccumulation; Biotechnology; Bone marrow; Cancer Research; Cell lines; Cell Movement; Coronary vessels; Critical Care Medicine; Embryogenesis; Embryonic Development - physiology; Embryonic growth stage; Endoderm; Endothelium; Germ cells; Gonadal Steroid Hormones - physiology; Hematology; Hematopoiesis; Hematopoietic Stem Cells - physiology; Hormones; Humans; Intensive; Internal Medicine; Islands; Leukemia; Medicine; Medicine & Public Health; Oncology; Patients; Pituitary; Primitive streak; Receptors; review; Sex hormones; Stem cell transplantation; Stem cells; Yolk; Yolk sac
• ISSN: 0887-6924; 1476-5551
• DOI: 10.1038/leu.2017.148

Evidence has accumulated that normal human and murine hematopoietic stem cells express several functional pituitary and gonadal sex hormones, and that, in fact, some sex hormones, such as androgens, have been employed for many years to stimulate hematopoiesis in patients with bone marrow aplasia. Interestingly, sex hormone receptors are also expressed by leukemic cell lines and blasts. In this review, I will discuss the emerging question of why hematopoietic cells express these receptors. A tempting hypothetical explanation for this phenomenon is that hematopoietic stem cells are related to subpopulation of migrating primordial germ cells. To support of this notion, the anatomical sites of origin of primitive and definitive hematopoiesis during embryonic development are tightly connected with the migratory route of primordial germ cells: from the proximal epiblast to the extraembryonic endoderm at the bottom of the yolk sac and then back to the embryo proper via the primitive streak to the aorta-gonado-mesonephros (AGM) region on the way to the genital ridges. The migration of these cells overlaps with the emergence of primitive hematopoiesis in the blood islands at the bottom of the yolk sac, and definitive hematopoiesis that occurs in hemogenic endothelium in the embryonic dorsal aorta in AGM region.