Low Magnitude of Compression Enhances Biosynthesis of Mesenchymal Stem Cells towards Nucleus Pulposus Cells via the TRPV4-Dependent Pathway

Abstract

Mesenchymal stem cell- (MSC-) based therapy is regarded as a promising tissue engineering strategy to achieve nucleus pulposus (NP) regeneration for the treatment of intervertebral disc degeneration (IDD). However, it is still a challenge to promote the biosynthesis of MSC to meet the requirement of NP regeneration. The purpose of this study was to optimize the compressive magnitude to enhance the extracellular matrix (ECM) deposition towards discogenesis of MSCs. Thus, we constructed a 3D culture model for MSCs to bear different magnitudes of compression for 7 days (5%, 10%, and 20% at the frequency of 1.0 Hz for 8 hours/day) using an intelligent and mechanically active bioreactor. Then, the underlying mechanotransduction mechanism of transient receptor potential vanilloid 4 (TRPV4) was further explored. The MSC-encapsulated hybrids were evaluated by Live/Dead staining, biochemical content assay, real-time PCR, Western blot, histological, and immunohistochemical analysis. The results showed that low-magnitude compression promoted anabolic response where high-magnitude compression induced the catabolic response for the 3D-cultured MSCs. The anabolic effect of low-magnitude compression could be inhibited by inhibiting TRPV4. Meanwhile, the activation of TRPV4 enhanced the biosynthesis analogous to low-magnitude compression. These findings demonstrate that low-magnitude compression promoted the anabolic response of ECM deposition towards discogenesis for the 3D-cultured MSCs and the TRPV4 channel plays a key role on mechanical signal transduction for low-magnitude compressive loading. Further understanding of this mechanism may provide insights into the development of new therapies for MSC-based NP regeneration.

SIRT1 alleviates high-magnitude compression-induced senescence in nucleus pulposus cells via PINK1-dependent mitophagy

“…The Gel-MA photocrosslinking hydrogels used as the scaffold for NP cell perfusion-culture in the bioreactor were freely provided by the Tissue Engineering Center of Third Military Medical University. And the cell-seeding procedure was performed according to our previous study [ 10 ]. Briefly, NP cells at passage II were trypsinized with 0.25% trypsin (Sigma, USA), and the suspension was then centrifuged at 1500 rpm for 10 min to deposit the cells.…”

Interaction between Mesenchymal Stem Cells and Intervertebral Disc Microenvironment: From Cell Therapy to Tissue Engineering

“…Similarly to IVD cells, cyclic mechanical loading has been shown to stimulate ECM production and chondrogenic differentiation of BM-MSCs [26] and NP-MSCs [37] in vitro. A study from Gan et al demonstrated that the anabolic response of BM-MSCs to low-magnitude compression was triggered by the activation of the mechanotransducer tran-sient receptor potential vanilloid 4 (TRPV-4) on the cell surface [107]. While mechanical loading may be a convenient resource to predifferentiate MSCs in view of a subsequent cell therapy, it could be speculated that the enhanced chondrogenic commitment of NP progenitors upon prolonged mechanical stimulation may contribute to the exhaustion of the resident stem cell compartment during IDD.…”

Biomaterials-Induced Stem Cells Specific Differentiation Into Intervertebral Disc Lineage Cells

“…A study developed TGF-β3-loaded PLGANPs to form a 3D culture system for MSCs. And it reported that low magnitudes (5%) loaded on the 3D culture system significantly upregulated GAG and hydroxyproline content, and promoted Collagen type II, aggrecan, sox-9 expressions both in transcript and protein levels, in which activation of transient receptor potential vanilloid 4 (TRPV4) channel played an important role in transducing mechanical signal (Gan et al, 2018). A multicomponent spinal motion segment encapsulating MSCs was established as a 3D model for IVD.…”