TGF-β1 enhances contractility in engineered skeletal muscle

Area of Science:

• Biomedical Engineering
• Regenerative Medicine
• Muscle Physiology

Background:

• Scaffoldless engineered 3D skeletal muscle tissue derived from satellite cells shows promise for replacing lost muscle tissue.
• Transforming growth factor-beta 1 (TGF-β1) is crucial for satellite cell migration and differentiation, and promotes collagen type I synthesis in the skeletal muscle extracellular matrix (ECM).

Purpose of the Study:

• To investigate the role of TGF-β1 in the formation and contractile function of in vitro engineered 3D skeletal muscle constructs.
• To determine the optimal concentration of TGF-β1 for enhancing skeletal muscle tissue engineering.

Main Methods:

• Engineered 3D skeletal muscle constructs were created using satellite cells.
• Varying concentrations of recombinant TGF-β1 (0, 0.5, 1.0, and 2.0 ng/ml) were added to the cell culture medium.
• Contractile function (twitch, tetanus, spontaneous force) and cellular structure (H&E, immunofluorescence for myosin heavy chains and collagen type I) were analyzed.

Main Results:

• The primary cell population consisted of 75% Pax7-positive cells before TGF-β1 addition.
• A concentration of 2.0 ng/ml TGF-β1 significantly increased peak force for twitch, tetanus, and spontaneous contractions compared to lower concentrations.
• Histological analysis revealed denser, better-organized myofibers and improved collagen type I deposition in constructs treated with 2.0 ng/ml TGF-β1.

Conclusions:

• The addition of 2.0 ng/ml TGF-β1 to the culture medium significantly enhances the contractility of engineered 3D skeletal muscle constructs.
• TGF-β1 promotes improved extracellular matrix organization, contributing to enhanced mechanical properties of engineered muscle tissue.
• These findings support the use of TGF-β1 as a key factor in optimizing skeletal muscle tissue engineering for therapeutic applications.