Making sense of hematopoietic stem cell niches

Abstract

The hematopoietic stem cell (HSC) niche commonly refers to the pairing of hematopoietic and mesenchymal cell populations that regulate HSC self-renewal, differentiation, and proliferation. Anatomic localization of the niche is a dynamic unit from the developmental stage that allows proliferating HSCs to expand before they reach the bone marrow where they adopt a quiescent phenotype that protects their integrity and functions. Recent studies have sought to clarify the complexity behind the HSC niche by assessing the contributions of specific cell populations to HSC maintenance. In particular, perivascular microenvironments in the bone marrow confer distinct vascular niches that regulate HSC quiescence and the supply of lineage-committed progenitors. Here, we review recent data on the cellular constituents and molecular mechanisms involved in the communication between HSCs and putative niches.

Extracellular vesicle miR-7977 is involved in hematopoietic dysfunction of mesenchymal stromal cells via poly(rC) binding protein 1 reduction in myeloid neoplasms

“…Conversely, Dicer1 knockout cells exhibited a reduction in JAG1 expression (GDS3404 and GDS4504). These findings suggest that osteoblasts and MSCs play different roles in supporting normal hematopoiesis, 37 and JAG1 expression could be regulated by β-catenin signaling and miRNA biogenesis. Consistent with these previous reports, we and others reported that mRNA expression of hematopoietic factors in MDS-derived MSCs was significantly disturbed.…”

Proteolytic fragments of fibronectin function as matrikines driving the chemotactic affinity of prostate cancer cells to human bone marrow mesenchymal stromal cells via the α5β1 integrin

“…2,3 The clinical observations that bone metastases from solid tumors from infancy to adulthood concord with the centripetal migration of hematopoiesis with aging suggest that bone metastases require subversion of the haematopoietic niche. Although endosteal, perivascular and other locations of the haematopoietic niche continue to be assessed, 4 mesenchymal stromal cells and their osteoblastic derivatives have been previously implicated as architects of the haematopoietic niche. [5][6][7] In experimental murine models prostate cancer cells can be demonstrated to compete with CD45C haematopoietic stem cells for a niche specified by osteoblasts.…”

Endosteal-like extracellular matrix expression on melt electrospun written scaffolds

“…HSCs [8,59,69,70]. However, other reports suggest that osteoblasts had no impact on primitive HSCs, but on committed B lymphocyte progenitors [71,72].…”