Mechanical overload is a major trigger of pathological cardiac remodeling (PCR), ultimately leading to heart failure. Understanding how cardiomyocytes respond to mechanical force signals and alter cellular states is crucial for developing treatments for PCR. However, the mechanosensitive alterations in myocardial proteome and metabolome involved in PCR remain unclear.
In this study, we established a cell model of mechanical stress-induced cardiac remodeling by applying cyclic mechanical stretch to adult mouse primary cardiomyocytes (AMCM). By adjusting different mechanical stretch parameters, we induced both physiological and pathological cardiac remodeling states. Excessive mechanical stress resulted in sarcomere disorganization, mitochondrial damage, and lipid accumulation in AMCM. We employed a multi-omics approach—including untargeted proteomics, metabolomics, and lipidomics—utilizing mass spectrometry to analyze the effects of varying mechanical stretch parameters on the mechanotransductive response of cardiomyocytes.
Comparative proteomic data between AMCM and myocardial cell line AC16 revealed for the first time that the high abundance of structural proteins (such as actin and myosin) as well as mitochondrial-related proteins (such as ATP synthase and citrate synthase) in adult primary cardiomyocytes significantly inhibited the detection of low-abundance proteins. Consequently, using timsTOF Pro 2 mass spectrometry platform, 4,885 proteins were identified in AMCM, which was significantly fewer than 7,790 proteins identified in AC16. Further quantification of 432 differentially expressed proteins from AMCM suggested a decrease in protein vesicle transport capacity, mitochondrial respiratory chain damage, and inhibition of oxidative phosphorylation with increasing mechanical stress. Using the AlteredPQR algorithm for membrane protein interaction network analysis, we revealed the activation of mechanosensitive ion channels such as Piezo and TRPC, leading to an imbalance in cardiac calcium homeostasis.
Integrating metabolomics and lipidomics data from stretched AMCM under different mechanical parameters, we observed aberrant lipid metabolism associated with amino acid metabolism remodeling. Construction of protein-metabolite interaction networks suggested that mechanical stress mediated myocardial lipid deposition, enhanced glutamine decomposition metabolism, increased arginine synthesis, and reduced alanine synthesis metabolism. These changes were possibly related to alterations in cell membrane composition, calcium homeostasis imbalance, and mitochondrial oxidative stress.
In summary, our findings reveal that mechanical stress alters cell membrane lipid composition and activates cardiac mechanosensitive ion channels, leading to calcium homeostasis imbalance, amino acid metabolism remodeling, inhibition of mitochondrial oxidative phosphorylation, ultimately contributing to pathological cardiac remodeling.