Combination of soluble factors and biomaterial scaffolds enhance human adipose-derived stem/stromal cell myogenesis

Considerations for enhanced mesenchymal stromal/stem cell myogenic commitment in vitro

The generation of tissue from stem cells is an alluring concept as it holds a number of potential applications in clinical therapeutics and regenerative medicine. Mesenchymal stromal/stem cells (MSCs) can be isolated from a number of different somatic sources, and have the capacity to differentiate into adipogenic, osteogenic, chondrogenic, and myogenic lineages. Although the first three have been extensively investigated, there remains a paucity of literature on the latter. This review looks at the various strategies available in vitro to enhance harvested MSC commitment and differentiation into the myogenic pathway. These include chemical inducers, myogenic-enhancing cell culture substrates, and mechanical and dynamic culturing conditions. Drawing on information from embryonic and postnatal myogenesis from somites, satellite, and myogenic progenitor cells, the mechanisms behind the chemical and mechanical induction strategies can be studied, and the sequential gene and signaling cascades can be used to monitor the progression of myogenic differentiation in the laboratory. Increased understanding of the stimuli and signaling mechanisms in the initial stages of MSC myogenic commitment will provide tools with which we can enhance their differentiation efficacy and advance the process to clinical translation.

Influence of extracellular cues of hydrogel biomaterials on stem cell fate

Tissue engineering is a multidisciplinary field that focuses on creating functional tissue through the combination of biomimetic scaffolds, a cell source, and biochemical/physiochemical cues. Stem cells are often used as the cell source due to their multipotent properties and autologous sourcing; however, the combination of physical and chemical cues that regulate their behavior creates challenges in reproducibly directing them to a specific fate. Hydrogel biomaterials are widely explored as tissue scaffolds due to their innate biomimetic properties and tailorability. For these constructs to be successful, properties such as surface chemistry and spatial configuration, stiffness, and degradability of the biomaterial used for the scaffold framework should be analogous to the natural environment of the tissue they are repairing/replacing. This is imperative, as cues from the surrounding extracellular matrix (ECM) influence stem cell behavior and direct cell differentiation to a specific lineage. Hydrogels offer great promise as tools to control stem cell fate, as researchers can modulate the degradation rates, mechanical properties, swelling behavior, and chemical properties of the biomaterial scaffold to mimic the instructive cues of the native ECM. Discussion of the advantages and challenges of utilizing hydrogel biomaterials as the basis of tissue scaffolds is reviewed herein, as well as specific examples of hydrogels in tissue engineering and advances in hydrogel research to achieve desired cell phenotypes.