Effect of biophysical cues on reprogramming to cardiomyocytes

Area of Science:

• Regenerative Medicine
• Cellular Reprogramming
• Biomaterials Science

Background:

• Fibroblast reprogramming into cardiomyocytes holds promise for cell therapy but suffers from low efficiency.
• Physical cues, such as mechanical stretch, substrate stiffness, and topography, are potential modulators of cellular reprogramming.
• Understanding how physical microenvironment influences reprogramming is crucial for improving efficiency.

Purpose of the Study:

• To investigate the impact of physical cues, specifically periodic mechanical stretch, substrate stiffness, and microgrooved substrates, on fibroblast reprogramming efficiency into cardiomyocytes.
• To elucidate the underlying mechanisms by which topographical cues influence cellular reprogramming and cardiomyocyte differentiation.

Main Methods:

• Fibroblasts were subjected to periodic mechanical stretch, cultured on substrates with varying stiffness, and seeded on microgrooved surfaces.
• Quantitative analysis of cardiomyocyte gene expression and assessment of partially and fully reprogrammed cardiomyocyte yield.
• Investigation of the role of Mkl1 activity and sarcomeric structure organization in response to microgrooved substrates.

Main Results:

• Periodic mechanical stretch and substrate stiffness did not significantly improve reprogramming yield.
• Microgrooved substrates enhanced cardiomyocyte gene expression by day 2 and increased the yield of partially reprogrammed cells by day 10.
• Combined microgroove culture with optimized protocols significantly increased the yield of functional cardiomyocytes exhibiting cardiac troponin T staining and spontaneous contractions.
• Microgrooves regulate Mkl1 activity and enhance sarcomeric structure organization, effects not fully recapitulated by biochemical approaches.

Conclusions:

• Topographical cues, particularly microgrooves, can significantly enhance the efficiency and yield of fibroblast reprogramming into cardiomyocytes.
• Microgroove-mediated enhancement involves regulation of Mkl1 activity and improved sarcomeric structure organization, offering a novel mechanism in cellular reprogramming.
• This study highlights the potential of biomaterial topography in advancing cell therapy and regenerative medicine strategies.