Development of a platform of 3D adipogenesis to model, at higher scale, the impact of LY2090314 compound on fibro/adipogenic progenitor adipogenic drift

In human dystrophies, the progressive muscle wasting is exacerbated by ectopic deposition of fat and fibrous tissue originating from fibro/adipogenic progenitors (FAPs). In degenerating muscles, the ability of these cells to adjuvate a successful healing is attenuated and FAPs aberrantly expand and differentiate into adipocytes and fibroblasts. Thus, arresting the fibroadipogenic fate of FAPs, without affecting their physiological role, represents a valuable therapeutic strategy for patients affected by muscle diseases. Here, using a panel of adipose progenitor cells including human-derived FAPs coupled with pharmacological perturbations and proteome profiling, we report that LY2090314 interferes with a genuine adipogenic program acting as WNT surrogate for the stabilization of a competent b-catenin transcriptional complex. To predict the beneficial impact of LY2090314 in limiting ectopic deposition of fat in human muscles, we combined the Poly-Ethylene-Glycol-Fibrinogen biomimetic matrix with these progenitor cells to create a miniaturized 3D model of adipogenesis. Using this scalable system, we demonstrated that a two-digit nanomolar dose of this compound is effective to repress adipogenesis in a higher 3D scale, thus offering a concrete proof for the use of LY2090314 to limit FAP-derived fat infiltrates in dystrophic muscles.

Fabrication of decellularized meniscus extracellular matrix according to inner cartilaginous, middle transitional, and outer fibrous zones result in zone-specific protein expression useful for precise replication of meniscus zones

Meniscus is a fibrocartilage composite tissue with three different microstructual zones, inner fibrocartilage, middle transitional, and outer fibrous zone. We hypothesized that decellularized meniscus extracellular matrix (DMECM) would have different characteristics according to zone of origin. We aimed to compare zone-specific DMECM in terms of biochemical characteristics and cellular interactions associated with tissue engineering. Micronized DMECM was fabricated from porcine meniscus divided into three microstructural zones. Characterization of DMECM was done by biochemical and proteomic analysis. Inner DMECM showed the highest glycosaminoglycan content, while middle DMECM showed the highest collagen content among groups. Proteomic analysis showed significant differences among DMECM groups. Inner DMECM showed better adhesion and migration potential to meniscus cells compared to other groups. DMECM resulted in expression of zone-specific differentiation markers when co-cultured with synovial mesenchymal stem cells (SMSCs). SMSCs combined with inner DMECM showed the highest glycosaminoglycan in vivo. Outer DMECM constructs, on the other hand, showed more fibrous tissue features, while middle DMECM constructs showed both inner and outer zone characteristics. In conclusion, DMECM showed different characteristics according to microstructural zones, and such material may be useful for zone-specific tissue engineering of meniscus.

Finite Element Analysis of Meniscal Anatomical 3D Scaffolds: Implications for Tissue Engineering

Solid Free-Form Fabrication (SFF) technologies allow the fabrication of anatomical 3D scaffolds from computer tomography (CT) or magnetic resonance imaging (MRI) patients’ dataset. These structures can be designed and fabricated with a variable, interconnected and accessible porous network, resulting in modulable mechanical properties, permeability, and architecture that can be tailored to mimic a specific tissue to replace or regenerate. In this study, we evaluated whether anatomical meniscal 3D scaffolds with matching mechanical properties and architecture are beneficial for meniscus replacement as compared to meniscectomy. After acquiring CT and MRI of porcine menisci, 3D fiber-deposited (3DF) scaffolds were fabricated with different architectures by varying the deposition pattern of the fibers comprising the final structure. The mechanical behaviour of 3DF scaffolds with different architectures and of porcine menisci was measured by static and dynamic mechanical analysis and the effect of these tissue engineering templates on articular cartilage was assessed by finite element analysis (FEA) and compared to healthy conditions or to meniscectomy. Results show that 3DF anatomical menisci scaffolds can be fabricated with pore different architectures and with mechanical properties matching those of natural menisci. FEA predicted a beneficial effect of meniscus replacement with 3D scaffolds in different mechanical loading conditions as compared to meniscectomy. No influence of the internal scaffold architecture was found on articular cartilage damage. Although FEA predictions should be further confirmed by in vitro and in vivo experiments, this study highlights meniscus replacement by SFF anatomical scaffolds as a potential alternative to meniscectomy.