Anisotropic Micro/Nanotopography Regulating Mitochondrial Dynamics in Cardiomyocytes

Introduction: Topographical cues of biomaterial scaffolds directly guide cell behaviors by determining integrin ligation and subsequent mechanotransducive pathways, but their influence on organelle (e.g., mitochondrion) behaviors remains unclear. Objectives: Considering the high sensitivity of mitochondria in cardiomyocytes to topographical signals, this study focused on investigating the impact of oriented micro/nano-wrinkled surfaces with varying wavelengths (0.5 to 25.0 μm) and amplitudes (0.05 to 4.30 μm) on the mitochondrial functions of rat embryonic myocardial cell line H9c2. Methods and Results: The results uncover a nonlinear response of cardiomyocyte behavior and mitochondrial homeostasis to these surface features. Notably, surfaces with a 3-μm wavelength and 0.7-μm amplitude (W3) promoted substantial cell elongation and orientation, whereas surfaces with a 0.5-μm wavelength and 0.05-μm amplitude (W0.5) triggered pronounced mitochondrial division. Remarkably, W0.5 topography facilitated mitochondrial division via cytoskeletal remodeling, involving vinculin and tubulin, which disrupted mitochondrial energy metabolism, enhanced reactive oxygen species (ROS)-mediated oxidative stress, and perturbed mitochondrial homeostasis by stimulating the adenosine 5'-monophosphate-activated protein kinase (AMPK) pathway. The transcriptomic analysis identifies the pivotal involvement of the p53, FoxO, mTOR, HIF-1, and AMPK signaling pathways in regulating mitochondrial dynamics in myocardial cells induced by W0.5, confirming the essential role of the polyadenylation signal (AATAAA) in modulating transcript splicing processes. Conclusion: Overall, this study offers important insights into the regulatory mechanisms by which aligned micro/nano topographical stimuli impact mitochondrial responses in cardiomyocytes, which hold potential for the development of novel biomaterial-focused approaches for diagnosing and treating cardiovascular diseases.