3D uniaxial mechanical stimulation induces tenogenic differentiation of tendon‐derived stem cells through a PI3K/AKT signaling pathway

Abstract

The tendon is a mechanosensitive tissue, but little is known about how mechanical stimulation selectively signals tenogenic differentiation and neo-tendon formation. In this study, we compared the impact of uniaxial and biaxial mechanical loading on tendon-derived stem cells (TDSCs). Our data show that there are variations in cell signaling and cell differentiation of mouse TDSCs in response to uniaxial and biaxial loading in monolayer culture. Whereas uniaxial loading induced TDSCs toward tenogenic and osteogenic differentiation, biaxial loading induced osteogenic, adipogenic, and chondrogenic differentiation of TDSCs. Furthermore, by applying uniaxial loading on 3-dimensional (3D) TDSC constructs, tenogenic-specific differentiation and neo-tendon formation were observed, results that were replicated in human TDSCs. We also showed that uniaxial loading induced PKB (AKT) phosphorylation (pAKT), whereas biaxial loading induced pERK. Most importantly, we found that inhibition of the PI3K/AKT signaling pathway could attenuate tenogenic differentiation and tendon formation in 3D TDSC constructs subjected to uniaxial loading. Taken together, our study highlights the importance of appropriate mechanobiological stimulation in 3D cell niches on tendon-like tissue formation and demonstrates that uniaxial mechanical loading plays an essential role in tenogenic differentiation and tendon formation by activating the PI3K/AKT signaling pathway.-Wang, T., Thien, C., Wang, C., Ni, M., Gao, J., Wang, A., Jiang, Q., Tuan, R. S., Zheng, Q., Zheng, M. H. 3D uniaxial mechanical stimulation induces tenogenic differentiation of tendon-derived stem cells through a PI3K/AKT signaling pathway.

Tendon stem progenitor cells: Understanding the biology to inform therapeutic strategies for tendon repair

“…Although biaxial loading had a clear effect, these genes are not tendon‐specific. In contrast, direct comparison of uniaxial and biaxial stimuli showed that uniaxial loading of TSPCs was more strongly pro‐tenogenic (and osteogenic) than biaxial loading, which induced a mixed osteogenic, adipogenic, and chondrogenic fate in TSPCs . Uniaxial loading of three‐dimensional (3D) TSPC constructs significantly enhanced tendon differentiation, mechanical properties, and neo‐tendon formation .…”

“…Another strategy to induce tenogenic differentiation, while preventing phenotypic drift of TSPCs, is to expose cells to mechanical cues similar to those experienced in the native microenvironment. 93,94 Although specific tendons undergo specific loading depending on anatomical location, the general type of loading for most tendons is uniaxial tension. To determine the effects of mechanical conditioning on TSPCs, cells are typically subjected to uniaxial or biaxial cyclic strain.…”

“…94 Uniaxial loading of three-dimensional (3D) TSPC constructs significantly enhanced tendon differentiation, mechanical properties, and neo-tendon formation. 94 Despite enhanced differentiation, it is unlikely that mechanical loading of na€ve TSPCs in the absence of biochemical stimuli will be sufficient for inducing a mature, tendon-specific phenotype.…”

Intramuscular Injection of Botox Induces Tendon Atrophy and Senescence of Tendon-Derived Stem Cells

“…Fluorescence-activated cell sorting was conducted to identify TDSCs ( Fig. 2A) before following experiments (positive for CD90 and CD44, and negative for CD34 and CD45) 38 . Early passage (P2) were used for all experiments described below.…”

“…Passage 2 TDSCs from were cultured to 100% con uence in a T75 ask then stimulated to differentiate into tenocytes by culturing for 7 days with complete medium supplemented with 25 ng/mL connective tissue growth factor (CTGF; PeproTech, Rocky Hill, NJ, USA) and 4.4 ng/mL ascorbic acid to promote extracellular matrix production 38 . Monolayer cell sheets were detached with 0.25% Trypsin and attached to the hook at the length of 10 mm to build a 3D TDSCs construct.…”