Extracellular matrix and α5β1 integrin signaling control the maintenance of bone formation capacity by human adipose-derived stromal cells

Abstract

Stromal vascular fraction (SVF) cells of human adipose tissue have the capacity to generate osteogenic grafts with intrinsic vasculogenic properties. However, adipose-derived stromal/stem cells (ASC), even after minimal monolayer expansion, display poor osteogenic capacity in vivo. We investigated whether ASC bone-forming capacity may be maintained by culture within a self-produced extracellular matrix (ECM) that recapitulates the native environment. SVF cells expanded without passaging up to 28 days (Unpass-ASC) deposited a fibronectin-rich extracellular matrix and displayed greater clonogenicity and differentiation potential in vitro compared to ASC expanded only for 6 days (P0-ASC) or for 28 days with regular passaging (Pass-ASC). When implanted subcutaneously, Unpass-ASC produced bone tissue similarly to SVF cells, in contrast to P0- and Pass-ASC, which mainly formed fibrous tissue. Interestingly, clonogenic progenitors from native SVF and Unpass-ASC expressed low levels of the fibronectin receptor α5 integrin (CD49e), which was instead upregulated in P0- and Pass-ASC. Mechanistically, induced activation of α5β1 integrin in Unpass-ASC led to a significant loss of bone formation in vivo. This study shows that ECM and regulation of α5β1-integrin signaling preserve ASC progenitor properties, including bone tissue-forming capacity, during in vitro expansion.

Single-cell RNA-seq highlights heterogeneity in human primary Wharton’s jelly mesenchymal stem/stromal cells cultured in vitro

“…2e). Integrin signaling pathway plays a critical role in homing of MSCs to the bone, osteogenic differentiation, and bone formation, and even some integrins are suggested as targets to promote bone formation and repair [85][86][87]. Several integrin genes were identified in our data with highly variable expression across the cells, such as ITGA5 and ITGB1, which respectively encode α5 and β1 and together form the α5β1 integrin, a cell surface receptor for fibronectin implicated in the control of osteoblastogenesis [87,88].…”

Single-cell RNA-seq highlights heterogeneity in human primary Wharton’s Jelly mesenchymal stem/stromal cells cultured in vitro

“…In terms of therapeutic potential, these genes are associated with functional characteristics of MSCs, such as integrin signaling pathway, angiogenesis, and inflammation mediated by chemokine and cytokine signaling pathway (Figure 2E). Integrin signaling pathway plays a critical role in homing of MSCs to bone, osteogenic differentiation, and bone formation, and even some integrins are suggested as targets to promote bone formation and repair (Di Maggio et al, 2017; Marie, 2013; Olivares-Navarrete et al, 2015). Several integrin genes were identified in our data with highly variable expression across the cells, such as ITGA5 and ITGB1 , which respectively encode α5 and β1 and together form the α5β1 integrin, a cell-surface receptor for fibronectin implicated in the control of osteoblastogenesis (Marie, 2013; Park et al, 2011).…”

Modulation of microenvironment for controlling the fate of periodontal ligament cells: the role of Rho/ROCK signaling and cytoskeletal dynamics

“…Recent studies have aimed to manipulate ECMmicroenvironment for tissue regeneration by using either artificial ECM or self-produced ECM as a scaffold in the stem cell therapy (Gobaa et al 2011;Martino et al 2014;Takewaki et al 2017;Di Maggio et al 2017;Zhu et al 2017). These studies have demonstrated strikingly improved regenerative efficiency and proposed promising approaches in clinical applications.…”