Hypergravity Upregulates and Simulated Microgravity Downregulates TRPM7 Mechanosensitive Ion Channel Expression in...

Area of Science:

• Cardiovascular Physiology
• Space Biology
• Molecular Biology

Background:

• Gravity variations, including hypergravity (HG) and microgravity (MG), affect cardiomyocyte function.
• Calcium (Ca2+) influx is crucial for cardiac cell activity and is modulated by gravity.
• TRP channels, particularly TRPM7, are key players in mechanically gated Ca2+ entry in cardiomyocytes.

Purpose of the Study:

• To investigate the relationship between TRPM7 channel protein synthesis and mRNA abundance in rat cardiomyocytes.
• To determine the effects of 14-day exposure to HG and MG on TRPM7 expression levels.

Main Methods:

• Transcriptome sequencing (RNA-Seq) with TPM normalization was used to quantify TRPM7 mRNA levels.
• Western blotting was employed to assess TRPM7 protein expression.
• Cardiomyocytes from rats exposed to HG or MG conditions were analyzed.

Main Results:

• TRPM7 mRNA levels (TPM values) significantly increased following HG exposure.
• TRPM7 mRNA levels significantly decreased following MG exposure.
• Western blotting confirmed a pronounced upregulation of TRPM7 protein under HG and a substantial downregulation under MG.

Conclusions:

• Both HG and MG significantly alter TRPM7 expression at both mRNA and protein levels in cardiomyocytes.
• These gravity-dependent changes in TRPM7 expression may influence ion channel conductance.
• Findings suggest a role for TRPM7 in the cardiac response to altered gravitational environments.