Hypergravity Enhances Stretch Sensitivity in Rat Cardiomyocytes via Increased Expression and Activity of Stretch-Activated Channels

This study investigated how 14-day 4g hypergravity exposure affects mechanosensitive ion channels (MSCs) in rat ventricular cardiomyocytes. RNA-seq revealed selective MSC remodeling: TRPM7 (+41%), TRPC1 (+68%), and TRAAK (+239%) were upregulated, while TRPV2 (-62%), Piezo2 (-58%), and Kir6.1 (-76%) were downregulated. Structural analysis showed 44% increased membrane capacitance and sarcomere elongation, consistent with hypertrophic remodeling. Patch-clamp studies demonstrated markedly hypersensitive stretch-activated currents (I_SAC), with activation at minimal displacements (1-2 µm) and enhanced responses under 4-10 µm stretch (107-222% of controls). These coordinated molecular, structural, and functional adaptations suggest targeted transcriptional reprogramming that balances enhanced Ca²? signaling with stabilized K? conductance, demonstrating cardiac mechanotransduction plasticity under gravitational stress with implications for cardiovascular risks in altered gravity environments. Overall design: Male Wistar rats (8 weeks old) were divided into two groups: hypergravity-exposed and control. The hypergravity group was subjected to 4g centrifugal force for 14 days (8 hours/day). Ventricular cardiomyocytes were isolated from both groups for RNA sequencing and electrophysiological analysis. RNA-Seq was performed to profile transcript levels of ion channels, while patch-clamp techniques assessed the sensitivity of stretch-activated currents (ISAC) to mechanical deformation. Data include raw RNA-Seq files and processed expression values for mechanically sensitive ion channels. *************************************************************** The table below lists GEO accessions reused/reanalyzed for this study. ***************************************************************