Mechanical stretch induces antioxidant responses and osteogenic differentiation in human mesenchymal stem cells through activation of the AMPK-SIRT1 signaling pathway

Abstract

Mesenchymal stem cells (MSCs) are promising cell sources for regenerative medicine. Growing evidence has indicated that mechanical stimuli are crucial for their lineage-specific differentiation. However, the effect of mechanical loading on redox balance and the intracellular antioxidant system in MSCs was unknown. In this study, human bone marrow-derived MSCs (BM-MSCs) were subjected to cyclic stretch at the magnitude of 2.5%, 5%, and 10%. Cell proliferation, intracellular reactive oxygen species (ROS), expression of antioxidant enzymes, and osteogenic differentiation were evaluated. RNA was extracted and subjected to DNA microarray analysis. Sirtinol and compound C were used to investigate the underlying mechanisms involved silent information regulator type 1 (SIRT1) and AMP-activated protein kinase (AMPK). Our results showed that mechanical stretch at appropriate magnitudes increased cell proliferation, up-regulated extracellular matrix organization, and down-regulated matrix disassembly. After 3 days of stretch, intracellular ROS in BM-MSCs were decreased but the levels of antioxidant enzymes, especially superoxide dismutase 1 (SOD1), were up-regulated. Osteogenesis was improved by 5% stretch rather than 10% stretch, as evidenced by increased matrix mineralization and osteogenic marker gene expression. The expression of SIRT1 and phosphorylation of AMPK were enhanced by mechanical stretch; however, inhibition of SIRT1 or AMPK abrogated the stretch-induced antioxidant effect on BM-MSCs and inhibited the stretch-mediated osteogenic differentiation. Our findings reveal that mechanical stretch induced antioxidant responses, attenuated intracellular ROS, and improved osteogenesis of BM-MSCs. The stretch-induced antioxidant effect was through activation of the AMPK-SIRT1 signaling pathway. Our findings demonstrated that appropriate mechanical stimulation can improve MSC antioxidant functions and benefit bone regeneration.

Involvement of mechanosensitive ion channels in the effects of mechanical stretch induces osteogenic differentiation in mouse bone marrow mesenchymal stem cells

“…Furthermore, the ECM production was enhanced after the cells were treated with mechanical stretch, which reveals that biological processes associated with osteoblast differentiation can be mediated by mechanical stretch. These findings are consistent with the previous study that the exposure of MSCs to cyclic stretch can upregulate the ECM organization and collagen fibril organization (Chen et al, 2018).…”

The role of sirtuin 1 and its activator, resveratrol in osteoarthritis

“…Increased SIRT1 could inhibit adipogenesis and stimulate myogenic differentiation in MSCs through activating Wnt/β-catenin signaling [50,51]. Other factors were also involved in the process of SIRT1 regulation of MSC, such as the activation of the adenosine monophosphate-activated protein kinase (AMPK)-SIRT1 signaling pathway as well as beneficial mechanical stretch to induce antioxidant responses, attenuate intracellular reactive oxygen species (ROS), and improve osteogenesis of human BM-MSCs [52]. In mice, Sirt1 promotes MSC proliferation and osteogenic differentiation and inhibits MSC senescence via Bmi1 activation; therefore, treatment with resveratrol could promote bone formation and prevent bone loss [53].…”

Sensory Neuropeptides and their Receptors Participate in Mechano-Regulation of Murine Macrophages

“…Cyclic stretch-induced ROS release from osteoblast-like cells [53]. Oppositely, the induction of an anti-oxidant response has been demonstrated in mesenchymal stem cells by Chen and co-workers lately [54]. In RAW macrophages, we observed no effect of cyclic stretch on ROS expression.…”