Ultrasound is a useful method in diagnostics, as it enables a deep and non-invasive observation of the body. Under certain conditions, ultrasound can stimulate cells, but this effect is very small and to amplify it, we need structures that amplify the ultrasound signal.
Protein gas vesicles are hollow protein structures expressed by some aquatic microorganisms to regulate buoyancy. Their cylindrical structure with conical ends is composed of the repetitive structural protein GvpB, while an additional seven proteins are necessary for proper vesicle assembly. Because of their gaseous interior, they behave differently from cells and tissues in the acoustic field. When stimulated with ultrasound, they emit an acoustic signal, which makes them an effective contrast agent for observation, and at the same time, due to the interaction with ultrasound waves, they transmit mechanical force to the surroundings.
Researchers from the Institute of Chemistry, together with colleagues from the Faculty of Medicine of UL, have determined the influence of individual proteins, which are necessary for the assembly of functional gas vesicles from the gene pool of Bacillus megaterium. Isolated vesicles were attached to the membrane proteins of mammalian cells. They monitored the effect of protein gas vesicles on the transmission of ultrasound to the cell. Under certain conditions, ultrasound causes the influx of calcium ions into mammalian cells and triggers the signaling pathways associated with it. In the article, they showed that cells to which gas vesicles are attached respond more strongly to ultrasound stimulation. Such an enhanced intake of calcium ions was used to improve the activation of artificial calcium-dependent transcription factors.
Gas vesicles, amplifiers of the ultrasound signal, enable a greater intake of calcium into the cells, which improves ultrasound therapy and shortens the time of cell stimulation.
The article was published in the journal ACS Nano, authors Vid Jazbec, Nina Varda, Ernest Šprager, Maja Meško, Sara Vidmar, Rok Romih, Marjetka Podobnik, Andreja Kežar, Roman Jerala, and Mojca Benčina.
Link: https://pubs.acs.org/doi/10.1021/acsnano.4c01498
Contact for more information: mojca.bencina(at)ki.si, Dr Benčina is the also the leader of CTGCT