Moshchenko, A. A. | bioRxiv Science

bioRxiv2024

Thermogenetics for cardiac pacing

Cardiac arrhythmias are common disorders that can be fatal. Modern methods of treating bradyarrhythmias include the implantation of pacemakers and cardioverter-defibrillators. However, implantable devices can cause various complications related to the electrodes installed inside the heart, including infection. Less invasive heart rhythm modulation could be beneficial for some cohorts of patients. Here, we demonstrate an alternative approach to heart pacing based on thermogenetics. We used adeno-associated viruses to deliver genetic human transient receptor potential subfamily V member 1 (TRPV1), a heat-sensitive cation channel, into isolated cardiomyocytes and the mouse heart. This allowed us to induce action potentials and control contractility using short heat pulses delivered by infrared laser illumination. Using this approach, we demonstrated the thermogenetic pacing of isolated cardiomyocytes in vitro and in the mouse heart in vivo. Our results demonstrate the potential of thermogenetics for developing therapeutic strategies for heart rhythm modulation.

synthetic biology↗

bioRxiv2023

Grubraw, a chemogenetic generator of mitochondrial pyruvate, reveals new mechanisms of mitochondrial metabolic control that underlie the Warburg effect

Upregulation of glycolysis and downregulation of mitochondrial oxidative phosphorylation, termed as the Warburg effect, are characteristic of tumor cells1,2. Restriction of pyruvate flux into the mitochondrial matrix is one of the major mechanisms underlying this phenomenon3. Warburg-type metabolism is beneficial for rapidly proliferating cells, however its function remains unclear. Moreover, it is unknown what the metabolic consequences of activation of mitochondrial respiration in Warburg-type cancer cells are. Here we created a chemogenetic instrument, Grubraw, that generates pyruvate directly in the mitochondrial matrix bypassing restricted pyruvate influx. In cancer cells, Grubraw-driven pyruvate synthesis in the matrix increased mitochondrial membrane potential, oxygen consumption rate, and the amounts of TCA cycle intermediates. In a mouse model of human melanoma xenografts, chemogenetic activation of mitochondria caused a decrease in tumor growth rate. Surprisingly, cancer cells actively exported pyruvate generated by Grubraw in the mitochondria into the extracellular medium. In addition, activation of mitochondria induced downregulation of transcription of the genes that drive cell cycle progression, cell proliferation and DNA replication. Our results demonstrate that cells with Warburg-type metabolism use previously unknown mechanisms of carbon flux control to dispose of excessive mitochondrial pyruvate, and activation of mitochondria in these cells downregulates cellular proliferation.

cancer biology↗