The Pericytic Phenotype of Adipose Tissue-Derived Stromal Cells Is Promoted by NOTCH2

Abstract

Long-term diabetes leads to macrovascular and microvascular complication. In diabetic retinopathy (DR), persistent hyperglycemia causes permanent loss of retinal pericytes and aberrant proliferation of microvascular endothelial cells (ECs). Adipose tissue-derived stromal cells (ASCs) may serve to functionally replace retinal pericytes and normalize retinal microvasculature during disease progression. We hypothesized that Notch signaling in ASC underlies regulation and stabilization of dysfunctional retinal microvascular networks such as in DR. ASC prominently and constitutively expressed NOTCH2. Genetic knockdown of NOTCH2 in ASC (SH-NOTCH2) disturbed the formation of vascular networks of human umbilical cord vein endothelial cells both on monolayers of ASC and in organotypical three-dimensional cocultures with ASC. On ASC SH-NOTCH2, cell surface platelet-derived growth factor receptor beta was downregulated which disrupted their migration toward the chemoattractant platelet-derived growth factor beta subunits (PDGF-BB) as well as to conditioned media from EC and bovine retinal EC. This chemoattractant is secreted by pro-angiogenic EC in newly formed microvascular networks to attract pericytes. Intravitreal injected ASC SH-NOTCH2 in oxygen-induced retinopathy mouse eyes did not engraft in the preexisting retinal microvasculature. However, the in vivo pro-angiogenic capacity of ASC SH-NOTCH2 did not differ from controls. In this respect, multifocal electroretinography displayed similar b-wave amplitudes in the avascular zones when either wild type ASC or SH-NOTCH2 ASC were injected. In conclusion, our results indicate that NOTCH2 is essential to support in vitro vasculogenesis via juxtacrine interactions. In contrast, ongoing in vivo angiogenesis is influenced by paracrine signaling of ASC, irrespective of Notch signaling. STEM CELLS 2018;36:240-251 SIGNIFICANCE STATEMENTIn this study, NOTCH2 is identified as a novel regulator of pericytic phenotype of human adipose tissue-derived stromal cells (ASCs). Results show that NOTCH2 modulates (a) ASC migration to the retinal microenvironment and (b) endothelial cells assembly in a vessel network formation in vitro. At the molecular level, NOTCH2 promotes the ASC pericytic phenotype through plateletderived growth factor receptor beta expression and sensitivity to chemoattractant.

Adipose tissue‐derived extracellular matrix hydrogels as a release platform for secreted paracrine factors

“…A soft hydrogel is also easier infiltrated by host cells like ASC and endothelial cells than stiff hydrogels. In this way, both ASC and endothelial cells can stimulate angiogenesis inside the hydrogel, which might result in increased wound healing rates (Terlizzi, Kolibabka, Burgess, Hammes, & Harmsen, 2017). It remains to be determined whether the stability and longevity of these hydrogels supports cells' maintenance, migra- ECM, which results in more cross links between proteins and therefore a high stability of the ECM proteins (Voziyan et al, 2014).…”

Adipose tissue-derived ECM hydrogels and their use as 3D culture scaffold

“…In addition, ASCs contribute to repair by differentiation into parenchymal or stromal cells, such as smooth muscle cells, pericytes, fibroblasts, adipocytes or osteoblasts, depending on the damaged tissue [8]. We have shown that ASCderived pericytes both promote and stabilize vascularization in vitro and in vivo in a NOTCH2-dependent fashion [10,11]. In these studies, we also cultured ASCs in 3D matrices of commercial extracellular matrix i.e.…”

Human adipose tissue-derived stromal cells act as functional pericytes in mice and suppress high-glucose-induced proinflammatory activation of bovine retinal endothelial cells

“…Recent studies suggested a direct role for ASCs in retinal microvascular support [ 16 ]. In rodent models of diabetic retinopathy, ASCs acquired pericytic features, which dampened proliferative angiogenesis [ 17 , 18 ]. Recently, we showed that the pericytic nature of ASCs depends on neurogenic locus notch homolog protein 2 (NOTCH2)-based juxtacrine interaction between ASCs and endothelial cells [ 18 ].…”