The haematopoietic stem cell niche at a glance

Abstract

Haematopoietic stem cells (HSCs) regulate the balanced turnover of erythrocytes, platelets and all immune cells by switching between self-renewal, differentiation, quiescence and (See poster insert)

Mesenchymal stromal cells from patients with myelodyplastic syndrome display distinct functional alterations that are modulated by lenalidomide

“…40 ANG1 expression was also reduced in HR-MSC. This cytokine is responsible for the maintenance of HSPC quiescence, 15 and its lower level in this MDS subset might also explain the reduced support of HSPC.…”

“…Mesenchymal stromal cells (MSC) are a main component of the hematopoietic niche; MSC and their progeny -endosteal osteoprogenitors, perivascular cells, nestin+ cells, CXCL12 abundant reticular cells, among others -regulate the localization, number, and fate of HSPC. [13][14][15] MSC also possess immunomodulatory activity and some reports point to a defect in this regard in MDS. [16][17] A recent study by our group also showed that the properties of MSC from healthy donors can be modulated by LEN treatment, 18 but whether this also applies to MSC derived from MDS patients is unknown.…”

<em>In Vivo</em> 4-Dimensional Tracking of Hematopoietic Stem and Progenitor Cells in Adult Mouse Calvarial Bone Marrow

“…The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood [1][2] .…”

“…It has been shown, through a number of functional studies based on ablating or overexpressing specific genes in either HSCs or the stromal cells of the microenvironment itself, that an intricate network of different cell types and regulatory signals is responsible for regulating the delicate balance between quiescence, proliferation, expansion and differentiation of HSCs [1][2] . The crosstalk between HSCs and their niches can be understood in depth only through direct observation.…”

“…The coordination of the complex signals leading to specific HSC fates relies upon the interaction between HSCs and the intricate bone marrow microenvironment, which is still poorly understood [1][2] .We describe how by combining a newly developed specimen holder for stable animal positioning with multi-step confocal and two-photon in vivo imaging techniques, it is possible to obtain high-resolution 3D stacks containing HSPCs and their surrounding niches and to monitor them over time through multi-point time-lapse imaging. High definition imaging allows detecting ex vivo labeled hematopoietic stem and progenitor cells (HSPCs) residing within the bone marrow.…”