Modulation of striated-muscle contractility by a high-affinity myosin-targeting peptide

Area of Science:

• Muscle physiology and biophysics
• Molecular mechanisms of muscle contraction
• Therapeutic applications in cardiovascular and neuromuscular diseases

Background:

• Myosin-based regulation is crucial for muscle function in health and disease.
• Myosin-targeted therapeutics offer potential treatments for heart failure and other muscle disorders.
• The MYH7 myosin's proximal subfragment 2 (S2) region is key to force generation and conformational changes.

Purpose of the Study:

• To develop and characterize a high-affinity peptide targeting the MYH7 myosin S2 region.
• To investigate the peptide's effects on myosin mechanical stability and muscle contractility.
• To establish a multi-scale structure-activity relationship for myosin-targeting peptides.

Main Methods:

• Biochemical and biophysical assays (e.g., single-molecule force spectroscopy, FRET).
• Enzymatic activity measurements (ATPase activity).
• Contractile measurements in demembranated and intact cardiac muscle cells.

Main Results:

• The peptide 'Stabilizer' binds myosin S2 with low nanomolar affinity.
• Stabilizer significantly enhances myosin mechanical stability.
• The peptide inhibits myofibrillar contractility, ATPase activity, and crossbridge kinetics, impacting muscle contraction and relaxation.

Conclusions:

• Myosin S2-targeting peptides, like Stabilizer, demonstrate significant potential as therapeutic agents.
• These peptides can modulate muscle contractile function, offering a novel treatment strategy for muscle diseases.
• The study establishes a foundation for developing myosin-based biologicals for therapeutic use.