Angiocrine functions of organ-specific endothelial cells

Abstract

Preface Endothelial cells lining blood vessel capillaries are not just passive conduits for delivering blood. Tissue-specific endothelium establish specialized vascular niches that deploy specific sets of growth factors, known as angiocrine factors, which actively participate in inducing, specifying, patterning, and guiding organ regeneration and maintaining homeostasis and metabolism. Angiocrine factors upregulated in response to injury orchestrates self-renewal and differentiation of tissue-specific repopulating resident stem and progenitor cells into functional organs. Uncovering the precise mechanisms whereby physiological-levels of angiocrine factors are spatially and temporally produced, and distributed by organotypic endothelium to repopulating cells, will lay the foundation for driving organ repair without scarring.

Quantification and three-dimensional microanatomical organization of the bone marrow

“…39 Vascular networks, aside from essential functions of nutrient delivery, waste removal, cellular trafficking, and angiocrine-mediated regulation of hematopoiesis, fulfill important structural roles. 40 Using 3D imaging, we and others have provided a detailed 3D overview of the microarchitecture of the microvascular system in different bones, which is composed of arterial and sinusoidal vessels (the venous equivalent of the BM), interconnected through a recently defined intermediate vascular type. 13,14,32,41,42 Collectively, the pervading BM vascular tree occupies 15% to 30% of the volume of BM, most of which corresponds to the wide, highly branched, labyrinth-like sinusoidal network 32 (C.N.-A., unpublished data) ( Figure 1A).…”

Endothelial cell regulation of salivary gland epithelial patterning

“…+ endothelial cells influence soluble factors that regulate SMG epithelial patterning and differentiation Angiocrine factors are juxtacrine-and paracrine-acting factors produced by endothelial cells that influence parenchymal epithelial cell differentiation, homeostasis and regeneration (Rafii et al, 2016). To screen for endothelial cell-dependent soluble factors that might influence the developing SMG epithelium, conditioned media from cultured endothelial cell-depleted mesenchyme and + (red) cell population relative to the Kit + (green) cell population in E12.5 SMGs organ explants grown for 48 h versus control glands.…”

“…Endothelial precursor cells are now acknowledged to produce angiocrine factors, which are paracrine-and juxtacrine-acting factors that control early organ patterning. Multiple angiocrine factors are produced by endothelial cells in every organ, and the profile of angiocrine factors is known to be organ specific (Rafii et al, 2016;Azizoglu and Cleaver, 2016). Angiocrine factors are known to regulate epithelial cell behaviors such as survival and proliferation, polarity, and differentiation (Ingthorsson et al, 2010;Hagiwara et al, 2015;Jaramillo et al, 2015;Kao et al, 2015).…”

“…Angiocrine factors are known to regulate epithelial cell behaviors such as survival and proliferation, polarity, and differentiation (Ingthorsson et al, 2010;Hagiwara et al, 2015;Jaramillo et al, 2015;Kao et al, 2015). Recent evidence demonstrates that vascular endothelial cell-mediated signaling regulates stem/ progenitor cell renewal and differentiation during organ development, homeostasis and repair/regeneration (Rafii et al, 2016).…”

Notch1 induces endothelial senescence and promotes tumor progression

“…in niches of the bone marrow. 1 The tumor vasculature differs morphologically and functionally from that of the healthy organ. There is increasing evidence that endothelial-derived signals, e.g., the expression of Notch ligands, increase the aggressiveness of tumor cells.…”