Neuromuscular disease modeling on a chip

Abstract

Organs-on-chips are broadly defined as microfabricated surfaces or devices designed to engineer cells into microscale tissues with native-like features and then extract physiologically relevant readouts at scale. Because they are generally compatible with patient-derived cells, these technologies can address many of the human relevance limitations of animal models. As a result, organs-on-chips have emerged as a promising new paradigm for patient-specific disease modeling and drug development. Because neuromuscular diseases span a broad range of rare conditions with diverse etiology and complex pathophysiology, they have been especially challenging to model in animals and thus are well suited for organ-on-chip approaches. In this Review, we first briefly summarize the challenges in neuromuscular disease modeling with animal models. Next, we describe a variety of existing organ-on-chip approaches for neuromuscular tissues, including a survey of cell sources for both muscle and nerve, and two- and three-dimensional neuromuscular tissue-engineering techniques. Although researchers have made tremendous advances in modeling neuromuscular diseases on a chip, the remaining challenges in cell sourcing, cell maturity, tissue assembly and readout capabilities limit their integration into the drug development pipeline today. However, as the field advances, models of healthy and diseased neuromuscular tissues on a chip, coupled with animal models, have vast potential as complementary tools for modeling multiple aspects of neuromuscular diseases and identifying new therapeutic strategies.

Innovative Human Three-Dimensional Tissue-Engineered Models as an Alternative to Animal Testing

“…Recently, the combination of several techniques of production or maturation, such as induced pluripotent stem cells, organoids, bioprinting, composite hydrogels, organ-on-chip, microphysiological systems, mechanical stimuli, innervation etc., (e.g., [ 312 , 313 , 314 , 315 , 316 ]), gave us the opportunity to produce a large spectra of complex organs. These organs could also be used for various applications such as potential transplantation (e.g., [ 317 ]) or disease modeling (e.g., [ 318 , 319 , 320 ]). For example, after demonstrating the functionality of hepatic cells bioprinted on collagen gels to drug screening [ 321 ], a mini-liver was produced using iPSC which differentiated into hepatocyte and self-organized into acini [ 322 ].…”

Engineering skeletal muscle tissues with advanced maturity improves synapse formation with human induced pluripotent stem cell-derived motor neurons

“…Immortalized human myoblasts have also been generated, 99,100 but these cells have not been commercialized and thus also remain relatively inaccessible. 15 More recently, protocols for differentiating myoblasts from hiPSCs have been established, 49 although they tend to suffer from low purity or yield 101 and limited maturity, 102 which will likely stunt NMJ formation. In contrast, primary chick myoblasts are easy to access and generate relatively mature muscle tissues, as evaluated in this study, and thus should be considered a suitable alternative for neuromuscular disease models.…”

“…Human induced pluripotent stem cell (hiPSC)-derived motor neurons have recently become a new paradigm for elucidating the impact of disease-relevant mutations on human motor neurons. 12–14 To leverage these cells to investigate NMJs in normal and pathological contexts, multiple approaches for co-culturing motor neurons and skeletal muscle have been attempted, 15 including seeding motor neurons on myotubes 16,17 and isolating cell types into microfabricated compartments. 18–20 However, most NMJs in vitro consistently fail to recapitulate the mature, pretzel-like structure of native NMJs and instead present patchy, blot-like structures.…”

Neuromuscular junction‐on‐a‐chip: ALS disease modeling and read‐out development in microfluidic devices

“…Human tissue-based 3D approaches include the use of ECM-embedded cells, NMJ organoids and 3D bioprinting. Advantages of ECM-embedded cells over 2D monolayers have been reported for both neuronal and skeletal muscle cultures (Santoso & McCain, 2020). ECM-embedded 3D muscle shows enhanced maturity (Smith et al, 2012) and contractility (Afshar Bakooshli et al 2019;Shima et al, 2018).…”