Regulation of the integrin αVβ3- actin filaments axis in early osteogenic differentiation of human mesenchymal stem cells under cyclic tensile stress

by Selleckchem | Jan 20 2024

Background: Integrins are closely related to mechanical conduction and play a crucial role in the osteogenesis of human mesenchymal stem cells. Here we wondered whether tensile stress could influence cell differentiation through integrin αVβ3.

Methods: We inhibited the function of integrin αVβ3 of human mesenchymal stem cells by treating with c(RGDyk). Using cytochalasin D and verteporfin to inhibit polymerization of microfilament and function of nuclear Yes-associated protein (YAP), respectively. For each application, mesenchymal stem cells were loaded by cyclic tensile stress of 10% at 0.5 Hz for 2 h daily. Mesenchymal stem cells were harvested on day 7 post-treatment. Western blotting and quantitative RT-PCR were used to detect the expression of alkaline phosphatase (ALP), RUNX2, β-actin, integrin αVβ3, talin-1, vinculin, FAK, and nuclear YAP. Immunofluorescence staining detected vinculin, actin filaments, and YAP nuclear localization.

Results: Cyclic tensile stress could increase the expression of ALP and RUNX2. Inhibition of integrin αVβ3 activation led to rearrangement of actin filaments and downregulated the expression of ALP, RUNX2 and promoted YAP nuclear localization. When microfilament polymerization was inhibited, ALP, RUNX2, and nuclear YAP nuclear localization decreased. Inhibition of YAP nuclear localization could reduce the expression of ALP and RUNX2.

Conclusions: Cyclic tensile stress promotes early osteogenesis of human mesenchymal stem cells via the integrin αVβ3-actin filaments axis. YAP nuclear localization participates in this process of human mesenchymal stem cells.

Comments:

It seems like you've conducted a study investigating the role of integrin αVβ3 and its relationship with mechanical stress in the osteogenesis of human mesenchymal stem cells. Your study utilized various inhibitors to explore the impact of integrin αVβ3, actin filaments, and nuclear Yes-associated protein (YAP) on cell differentiation under cyclic tensile stress. Here's a breakdown of your methodology and findings:

### Methods:
- **Cell Treatment:** Inhibition of integrin αVβ3 using c(RGDyk), cytochalasin D for microfilament polymerization inhibition, and verteporfin for YAP function inhibition.
- **Tensile Stress:** Application of cyclic tensile stress (10% at 0.5 Hz for 2 hours daily) to mesenchymal stem cells.
- **Analysis:** Western blotting and quantitative RT-PCR to assess expression levels of ALP, RUNX2, β-actin, integrin αVβ3, talin-1, vinculin, FAK, and nuclear YAP. Immunofluorescence staining for vinculin, actin filaments, and YAP nuclear localization.

### Results:
- **Tensile Stress Effects:** Increased ALP and RUNX2 expression, indicating promotion of early osteogenesis.
- **Inhibition of Integrin αVβ3:** Resulted in actin filament rearrangement, decreased ALP and RUNX2 expression, and promoted YAP nuclear localization.
- **Microfilament Polymerization Inhibition:** Decreased ALP, RUNX2 expression, and YAP nuclear localization.
- **Inhibition of YAP Nuclear Localization:** Reduced ALP and RUNX2 expression.

### Conclusions:
- **Tensile Stress & Integrin αVβ3:** Cyclic tensile stress promotes early osteogenesis via the integrin αVβ3-actin filaments axis.
- **YAP Nuclear Localization:** YAP nuclear localization plays a role in the osteogenic process of human mesenchymal stem cells.

This study provides valuable insights into the mechanotransduction mechanisms involved in osteogenesis, linking integrin αVβ3, actin filaments, and YAP nuclear localization to the response of mesenchymal stem cells to mechanical stress. These findings could have implications in understanding bone formation and potentially contribute to strategies for bone tissue engineering or regenerative medicine.