Sonogenetic control of transgene expression by gas-filled protein nanostructures

• Applicant: Dr. Manuel Iburg
• Subject Area: Biochemistry ; Cell Biology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 511048568

A robust method to control gene expression of engineered cell in animal models and humans will provide pivotal capabilities for basic research and therapeutic applications. Ideally, the method should offer spatial focusing, be operable in centimeter-deep tissue and offer the potential for multiplexed control of several groups of cells while minimizing off-target effects. In this project, I aim to develop a novel sonogenetic method of cellular control by leveraging the unique mechanical interaction between gas vesicles (GVs) and ultrasound. GVs are a class of gas-filled protein nanostructures with unique mechanical properties found in photosynthetic microbes. In contrast to normal aqueous tissue, the gas-water interface of GVs allows for strong interactions with ultrasound. Ultrasound pulses above a certain threshold pressure will collapse GVs, exposing their hydrophobic inner surface, resulting in protein aggregation. Notably, a millisecond pulse using clinical imaging ultrasound is sufficient to collapse GVs, resulting in no tissue perturbation and negligible off-target tissue heating. Different genetic variants of GVs have variable threshold pressure, potentially enabling multiplexed control. To link GV collapse to genetic transcriptional activation, I will equip cells with “sensors” of GV collapse that are either based on exogenous proteins that assemble on the collapsed GV, endogenous proteins that are “trapped” in collapsing GVs, or cellular stress responses that are triggered by proteotoxic stress upon GV aggregate formation. These sensors will be coupled with actuators that trigger a transcriptional response in genetic circuits, driving reporter gene expression. I will conclude the proposed project by providing the first demonstration of the method in triggering gene expression in model bacteria by ultrasound. This will set the stage for future development of the method in therapeutically relevant bacterial and mammalian cells, animal models and translation to clinical application. In sum, GV-based sonogenetics will be a single-shot, multiplexed, non-invasive method that can operate in deep tissue with minimal effect on the surrounding cells and broadly benefit basic research in neuroscience and cell biology as well as drive the development of cell-based therapies.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professor Dr. George Lu