Preparation of 3D Decellularized Matrices from Fetal Mouse Skeletal Muscle for Cell Culture.

The extracellular matrix (ECM) plays a crucial role in providing structural support for cells and conveying signals that are important for various cellular processes. Two-dimensional (2D) cell culture models oversimplify the complex interactions between cells and the ECM, as the lack of a complete three-dimensional (3D) support can alter cell behavior, making them inadequate for understanding in vivo processes. Deficiencies in ECM composition and cell-ECM interactions are important contributors to a variety of different diseases. One example is LAMA2-congenital muscular dystrophy (LAMA2-CMD), where the absence or reduction of functional laminin 211 and 221 can lead to severe hypotony, detectable at or soon after birth. Previous work using a mouse model of the disease suggests that its onset occurs during fetal myogenesis. The present study aimed to develop a 3D in vitro model permitting the study of the interactions between muscle cells and the fetal muscle ECM, mimicking the native microenvironment. This protocol uses deep back muscles dissected from E18.5 mouse fetuses, treated with a hypotonic buffer, an anionic detergent, and DNase. The resultant decellularized matrices (dECMs) retained all ECM proteins tested (laminin α2, total laminins, fibronectin, collagen I, and collagen IV) compared to the native tissue. When C2C12 myoblasts were seeded on top of these dECMs, they penetrated and colonized the dECMs, which supported their proliferation and differentiation. Furthermore, the C2C12 cells produced ECM proteins, contributing to the remodeling of their niche within the dECMs. The establishment of this in vitro platform provides a new promising approach to unravel the processes involved in the onset of LAMA2-CMD, and has the potential to be adapted to other skeletal muscle diseases where deficiencies in communication between the ECM and skeletal muscle cells contribute to disease progression.