Hemapoietic Stem Cell and Initial Stages of Hemopoiesis: Research Methods and Modern Concepts

Hematopoietic stem cells (HSCs) have long been one of the most well-studied type of stem cells. Multiple experimental and clinical studies allowed for characterizing the main HSC properties and elaborating methodological approaches for their analyses and ultimately led to the formulation of a hierarchical theory of hematopoiesis. According to the hierarchical theory, HSCs stand at the root of the hematopoietic tree and are characterized by high self-renewal and multipotent differentiation capacities. Following the differentiation, HSC successively give rise to diverse hematopoietic precursors that ultimately produce the whole variety of differentiated blood cells. The concept on the strict sequence of HSC differentiation has recently changed, largely due to the development and implementation of new hi-tech methods of cell differentiation analysis. This review summarizes classical views on HSC biology and early stages of their differentiation, outlines the main methodological approaches used in HSC studies, and discusses recent achievements and modern views on the early stages of hematopoiesis.