Posts tagged Skeletal Muscle Cells
Combinatorial extracellular matrix cues with mechanical strain induce differential effects on myogenesis in vitro
Combinatorial extracellular matrix cues with mechanical strain induce differential effects on myogenesis in vitro

Abstract: Skeletal muscle regeneration remains a clinical unmet need for volumetric muscle loss and atrophy where muscle function cannot be restored to prior capacity. Current experimental approaches do not account for the complex microenvironmental factors that modulate myogenesis. In this study we developed a biomimetic tissue chip platform to systematically study the combined effects of the extracellular matrix (ECM) microenvironment and mechanical strain on myogenesis of murine myoblasts. Using stretchable tissue chips composed of collagen I (C), fibronectin (F) and laminin (L), as well as their combinations thereof, we tested the addition of mechanical strain regimens on myogenesis at the transcriptomic and translational levels. Our results show that ECMs have a significant effect on myotube formation in C2C12 murine myoblasts. Under static conditions, laminin substrates induced the longest myotubes, whereas fibronectin produced the widest myotubes. Combinatorial ECMs showed non-intuitive effects on myotube formation. Genome-wide analysis revealed the upregulation in actin cytoskeletal related genes that are suggestive of myogenesis. When mechanical strain was introduced to C + F + L combinatorial ECM substrates in the form of constant or intermittent uniaxial strain at low (5%) and high (15%) levels, we observed synergistic enhancements in myotube width, along with transcriptomic upregulation in myosin heavy chain genes. Together, these studies highlight the complex role of microenvironmental factors such as ECM interactions and strain on myotube formation and the underlying signaling pathways.

Originally Published in: Biomaterials Science (2023) (Link to Paper)

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Curi CytostretcherArianna KieserSkeletal Muscle Cells
High-throughput, real-time monitoring of engineered skeletal muscle function using magnetic sensing
High-throughput, real-time monitoring of engineered skeletal muscle function using magnetic sensing

Abstract: Engineered muscle tissues represent powerful tools for examining tissue level contractile properties of skeletal muscle. However, limitations in the throughput associated with standard analysis methods limit their utility for longitudinal study, high throughput drug screens, and disease modeling. Here we present a method for integrating 3D engineered skeletal muscles with a magnetic sensing system to facilitate non-invasive, longitudinal analysis of developing contraction kinetics. Using this platform, we show that engineered skeletal muscle tissues derived from both induced pluripotent stem cell and primary sources undergo improvements in contractile output over time in culture. We demonstrate how magnetic sensing of contractility can be employed for simultaneous assessment of multiple tissues subjected to different doses of known skeletal muscle inotropes as well as the stratification of healthy versus diseased functional profiles in normal and dystrophic muscle cells. Based on these data, this combined culture system and magnet-based contractility platform greatly broadens the potential for 3D engineered skeletal muscle tissues to impact the translation of novel therapies from the lab to the clinic.

Originally Published in: Sage Journals (2022) (Link to Paper)

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MantarrayArianna KieserSkeletal Muscle Cells
Passive-Stretch Induced Skeletal Muscle Injury Platform for Duchenne Muscular Dystrophy Modeling

Inactivity following skeletal muscle dysfunction in DMD usually causes compromised soft tissue and decreased joint range of motion. Passive stretch techniques in combination with an exercise program are used as interventions to prevent musculoskeletal complications in children with DMD. However, the exact role of stretch-based rehabilitation methods is not well established in children with DMD. In fact, the underlying molecular and cellular mechanisms of how stretch-based rehabilitation methods in dystrophin-deficient muscle fibers might worsen the disease phenotype have not been fully explained. Therefore, the purpose was to establish an in vitro stretch-induced injury model in normal and dystrophic rat skeletal muscle fibers.

Originally Published in: Archives of Physical Medicine and Rehabilitation - V103, Issue 3 (2022) (Link to Paper)

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Curi CytostretcherArianna KieserSkeletal Muscle Cells
Matrix Topography Regulates Synaptic Transmission at the Neuromuscular Junction
Matrix Topography Regulates Synaptic Transmission at the Neuromuscular Junction

Recreation of a muscle that can be controlled by the nervous system would provide a major breakthrough for treatments of injury and diseases. However, the underlying basis of how neuron–muscle interfaces are formed is still not understood sufficiently. Here, it is hypothesized that substrate topography regulates neural innervation and synaptic transmission by mediating the cross-talk between neurons and muscles. This hypothesis is examined by differentiating neural stem cells on the myotubes, formed on the substrate with controlled groove width. The substrate with the groove width of 1600 nm, a similar size to the myofibril diameter, serves to produce larger and aligned myotubes than the flat substrate. The myotubes formed on the grooved substrate display increases in the acetylcholine receptor expression. Reciprocally, motor neuron progenitor cells differentiated from neural stem cells innervate the larger and aligned myotubes more actively than randomly oriented myotubes. The results of this study will be broadly useful for improving the quality of engineered muscle used in a series of applications including drug screening, regeneration therapies, and biological machinery assembly.

Originally Published in: Advanced Science (2019) (Link to Paper)

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NanoSurface PlatesArianna KieserSkeletal Muscle Cells, Neuromuscular Junctions, Neurons