How to use intercellular mail

Membrane vesicles, in which cells transmit chemical signals to each other, can be used for medical purposes

Kirill Stasevich, "Science and Life"

Our cells communicate in different ways, and if, for example, there is some distance between them, then the cells either simply secrete signaling substances outside in the expectation that they will reach the recipient, or pack the message in special membrane bubbles. They are called vesicles – when they get to another cell, they sit on its outer membrane, and the contents of the parcel end up in the cytoplasm. 

Messages in vesicles may be different, but it is known that the cell packs substances into such parcels, which it itself most often uses. This means, for example, that stem cells send molecules via vesicular mail that stimulate cell division and some other processes peculiar to stem cells. 

Now imagine that there are problems in some tissue, that in some organ it is urgently necessary to replace the dead cells with new ones, and for some reason the organ's own resources are not enough for this. In this case, if we force some other cells to send a chemical package there, then the problem will be solved faster. In other words, the membrane vesicles that cells secrete from themselves could play a big role in medicine. 

Indeed, their therapeutic potential has already been evaluated in experiments that simulated damage to the kidneys, heart, liver and even nervous tissue. It would be very convenient if such "parcels" could be worked out in the laboratory, so that they could then be applied at the right time in the right place. 

Some substances induce cells to secrete vesicles – such substances include cytochalazine B. This is a toxin from fungi that easily penetrates into the cell and paralyzes some processes associated with the assembly and disassembly of the cytoskeleton, as a result of which, as we have just said, cells produce many membrane vesicles-"parcels".

Such bubbles that have arisen due to cytochalazine, as well as ordinary vesicles, are quite capable of interacting with other cells - they carry all the necessary receptors and the "docking" apparatus. They can be collected, filled with some substance - for example, drug molecules or nanoparticles – and sent to the body. 

But what about their own properties – do they carry the cell's own substances, or do membrane parcels lose their biological activity because of this method of obtaining? Staff Kazan University together with colleagues from several foreign scientific centers used cytochalazine B on human neuroblastoma cells. 

Neuroblastoma tumor forms a lot of blood vessels in itself, which means that its cells contain a lot of relevant signaling substances; it is known that connective tissue stem cells, once next to neuroblastoma cells, begin to actively build capillaries. 

In an article in Oncotarget, Albert Rizvanov and his colleagues write that the vesicles that neuroblastoma cells actively secreted under the action of cytochalazine turned out to be exactly the same in biological activity as expected – they prompted stem cells to build a vascular network. The signaling "parcels" contained a lot of vascular endothelial growth factor (this protein activates the formation of blood vessels), in size and in other parameters they were also similar to ordinary vesicles.

Vesicles-vesicles formed by neuroblastoma cells: on the left – an image from an electron microscope, on the right – from a scanning electron microscope. (Photo: Marina O. Gomzikova et al., Oncotarget, 2017.)

Of course, in this case, experiments were conducted with malignant cells, but the results allow us to assume with confidence that all other types of cells can also be "milked" with cytochalazine. And if we know that a substance from a certain type of cell can help another type of cell, then we do not need to manipulate whole cells, transfer them from one place to another, fearing side effects - it is enough to use vesicular mail, because membrane bubbles are needed to transmit messages. 

The same cancer cells not only force other cells to form vessels for the tumor – it is known that they also send out special messages that either turn a healthy cell into a cancerous one, or prepare healthy tissue for the arrival of tumor metastases. But cancer cells, in turn, can be bombarded with signals from other cells that will force them to die, and it is likely that antitumor "bubble therapy" will soon appear in the clinic. 

Portal "Eternal youth" http://vechnayamolodost.ru  31.08.2017