Acoustic tweezing cytometry enhances osteogenesis of human mesenchymal stem cells through cytoskeletal contractility and YAP activation

Abstract

Human mesenchymal stem cells (hMSCs) have great potential for cell-based therapies for treating degenerative bone diseases. It is known that mechanical cues in the cell microenvironment play an important role in regulating osteogenic (bone) differentiation of hMSCs. However, mechanoregulation of lineage commitment of hMSCs in conventional two-dimensional (2D) monocultures or bioengineered three-dimensional (3D) tissue constructs remains suboptimal due to complex biomaterial design criteria for hMSC culture. In this study, we demonstrate the feasibility of a novel cell mechanics and mechanobiology tool, acoustic tweezing cytometry (ATC), for mechanical stimulation of hMSCs. ATC utilizes ultrasound (US) pulses to actuate functionalized lipid microbubbles (MBs) which are covalently attached to hMSCs via integrin binding to exert forces to the cells. ATC stimulation increases cytoskeletal contractility of hMSCs regardless of the cell area. Furthermore, ATC application rescues osteogenic differentiation of hMSCs in culture conditions that are intrinsically repressive for hMSC osteogenesis (e.g., soft cell culture surfaces). ATC application activates transcriptional regulator YAP to enhance hMSC osteogenesis. Our data further show that F-actin, myosin II, and RhoA/ROCK signaling function upstream of YAP activity in mediating ATC-stimulated hMSC osteogenesis. With the capability of applying controlled dynamic mechanical stimuli to cells, ATC provides a powerful tool for mechanoregulation of stem cell behaviors in tissue engineering and regenerative medicine applications.

Topography induced stiffness alteration of stem cells influences osteogenic differentiation

“…Our results are consistent with Dalby, Furukawa and Fu's study, which demonstrate that osteogenesis is mediated by enhanced focal adhesion, 28 actin polymerization 25 and YAP activation. 64 A schematic representation of the mechanistic phenome at play is illustrated in Fig. 10 and describes the effect of similar C AR , stimulated by different wrinkle dimensions, on the osteogenic differentiation, which is at least partly mediated by the mechanical properties of hBM-MSCs and possibly connected to the focal adhesions providing the contact guidance information and YAP signal pathway.…”

Low-Intensity Pulsed Ultrasound Protects Retinal Ganglion Cell From Optic Nerve Injury Induced Apoptosis via Yes Associated Protein

“…Recent studies have indicated the importance of YAP signaling in mediating transcriptional activity from upstream mechanosensitive human Mesenchymal Stem Cell (hMSC) osteogenesis ( Xue et al, 2017 ). Nonetheless, it also indicated that YAP/TAZ has the ability to link cell mechanics to Notch signaling in controlling epidermal stem cell fate and peripheral myelination ( Poitelon et al, 2016 ; Totaro et al, 2017 ).…”

Acoustic Tweezing Cytometry Induces Rapid Initiation of Human Embryonic Stem Cell Differentiation

“…Contractile force measurements were performed as described before 35 . Briefly, hESCs were seeded on PDMS micropost array (PMA) either as single cells or colonies, and incubated overnight to allow attachment.…”