Niches for Skeletal Stem Cells of Mesenchymal Origin

Abstract

With very few exceptions, all adult tissues in mammals are maintained and can be renewed by stem cells that self-renew and generate the committed progeny required. These functions are regulated by a specific and in many ways unique microenvironment in stem cell niches. In most cases disruption of an adult stem cell niche leads to depletion of stem cells, followed by impairment of the ability of the tissue in question to maintain its functions. The presence of stem cells, often referred to as mesenchymal stem cells (MSCs) or multipotent bone marrow stromal cells (BMSCs), in the adult skeleton has long been realized. In recent years there has been exceptional progress in identifying and characterizing BMSCs in terms of their capacity to generate specific types of skeletal cells in vivo . Such BMSCs are often referred to as skeletal stem cells (SSCs) or skeletal stem and progenitor cells (SSPCs), with the latter term being used throughout this review. SSPCs have been detected in the bone marrow, periosteum, and growth plate and characterized in vivo on the basis of various genetic markers (i.e., Nestin, Leptin receptor, Gremlin1, Cathepsin-K, etc.). However, the niches in which these cells reside have received less attention. Here, we summarize the current scientific literature on stem cell niches for the SSPCs identified so far and discuss potential factors and environmental cues of importance in these niches in vivo . In this context we focus on (i) articular cartilage, (ii) growth plate cartilage, (iii) periosteum, (iv) the adult endosteal compartment, and (v) the developing endosteal compartment, in that order.

Phosphorylation inhibition of protein-tyrosine phosphatase 1B tyrosine-152 induces bone regeneration coupled with angiogenesis for bone tissue engineering

“…Recruitment of a sufficient number of MSCs and ECs from the bone marrow and periosteum of adjacent tissues to the bone defect area is required for bone repair [ 2 ]. MSCs mainly reside in the bone marrow pool and periosteum under physiological conditions, and they live in a particular microenvironment called stem cell niches [ 3 ]. Most MSCs and osteoblast progenitor cells are very prominent around vessels [ 4 ].…”

The CNS/PNS Extracellular Matrix Provides Instructive Guidance Cues to Neural Cells and Neuroregulatory Proteins in Neural Development and Repair

“…Confirmatory immunolocalisations with a range of ECM antibodies are warranted. A large range of antibodies are available to immunolocalise ECM niche components and stage neuronal development in both normal and neurodegenerative neural tissues [ 309 , 310 ].…”

Mesenchymal Stromal Cells as Critical Contributors to Tissue Regeneration

“…Since LepR-positive MSCs are localized in close proximity to the sinusoids and arterioles of the bone marrow, it can be assumed that endothelial cells are components of the mesenchymal stem cell niche. This is supported by the presence of extensive crosstalk between MSCs and endothelial cells via PDGFR, BMP, and Notch signaling (Kurenkova et al, 2020 ).…”