Matrix Composition and Mechanics Direct Proangiogenic Signaling from Mesenchymal Stem Cells

Abstract

The secretion of trophic factors that promote angiogenesis from mesenchymal stem cells (MSCs) is a promising cell-based therapeutic treatment. However, clinical efficacy has proved variable, likely on account of ill-defined cell delivery formulations and the inherent complexity of cellular secretion. Here we show how controlling the mechanical properties and protein composition of the extracellular matrix (ECM) surrounding MSCs can guide proangiogenic signaling. Conditioned media from MSCs adherent to polyacrylamide hydrogel functionalized with fibronectin, collagen I, or laminin was applied to 3D matrigel cultures containing human microvascular endothelial cells (HMVECs). The degree of tubulogenesis in HMVECs is shown to depend on both the substrate rigidity and matrix protein composition. MSCs cultured on fibronectin-modified hydrogels show a stiffness dependence in proangiogenic signaling with maximum influence on tubulogenesis observed from 40 kPa conditioned media, twofold higher than commercially available cocktails of growth factors. Quantitative real-timepolymerase chain reaction reveals stiffness-dependent expression of multiple factors involved in angiogenesis that corroborate the functional tubulogenesis assay. Restricting cell spreading with micropatterned surfaces attenuates the conditioned media effects; however, small-molecule inhibitors of actomyosin contractility do not significantly reduce the functional outcome. This work demonstrates how controlling matrix rigidity and protein composition can influence the secretory profile of MSCs. Model systems that deconstruct the physical and biochemical cues involved in MSC secretion may assist in the design of hydrogel biomaterials for cell-based therapies.

Anti-inflammatory ω-3 endocannabinoid epoxides

“…Similarly, endocannabinoids are recognized for their ability to inhibit cancer, in part through their antiangiogenic properties (49,50). To determine if the EEQEAs and EDP-EAs demonstrate a greater, similar, or diminished ability to inhibit angiogenesis, we performed a Matrigel tubulogenesis assay using HMVECs and proangiogenic VEGF, as previously described (51). As shown in Fig.…”

“…The EEQ, EEQ-EA, EDP, and EDP-EA inhibition of VEGF-promoted tube formation was assessed in HMVECs (Cell Systems) as previously described (51). Briefly, 35 μL of Matrigel was plated on the bottom of a 48-well plate and allowed to gel for 30 min at 37°C.…”

Capturing extracellular matrix properties in vitro: Microengineering materials to decipher cell and tissue level processes

“…49 These strategies recapture several aspects of the in vivo environment but relinquish some control over the precise environment presented to cells. Matrix composition has been found to influence diverse aspects of cell behavior such as extracellular signal-regulated kinases (ERK) activation by mechanical strain in smooth muscle cells, 50 endothelial cells network formation and their response to transforming growth factor-b, 51 secretome, 38 cancer progression, 52 and stem cell fate. 53 We and other groups have shown previously that for mesenchymal stem cells (MSCs), matrix composition can direct cell differentiation and mediate how cells respond to other cues.…”

Biomaterials Application in Stem Cell Therapies for Stroke

“…For instance, NSPCs transplanted in a 3.5-kPa matrix will mount a proliferative response and following a slow degradation of hydrogel biopolymer and descent of stiffness to < 1 kPa, their self-renewal slows and NSPCs start differentiating to neuron. Besides differentiation, other proregenerative functions of stem/progenitor cells such as their secretory profile are also controlled by matrix stiffness [111].…”

“…NSPCs perceive lack of oxygen and nutrients by expressing the transcription factor hypoxiainduced factor-1 that leads to increased secretion of VEGF [139]. Secretory support of angiogenesis by NSPCs could be enhanced when they are encapsulated within a hydrogel with 40 kPa (compressive modulus) [111]; this is another example of how mechanical properties contribute to regenerative potential of cell scaffolds.…”