Scientists have found a way not to dangle without sleep. However, while the method was checked only on rodents.
The lack of sleep beats not only in the mood and attention. When a lack of sleep lasts for a long time, the brain begins to work in the mode of chronic stress: inflammation increases, memories are worse fixed, learning and decision-making suffers worse. Chinese researchers have tested a new way to mitigate these effects in mice. Instead of conventional medicine, they used exosomes - tiny bubbles through which cells transmit each other biological molecules.
The work was carried out by the team of the First Cuanzhou Hospital, associated with Fujian Medical University. The researchers tried to deliver the heat shock protein HSP70 to the brain. This protein helps cells experience stress, protects protein structures from damage and improper folding. The problem is that the brain is protected by a blood-brain barrier: many substances do not pass from the blood to the nervous tissue. Therefore, scientists decided to use exosomes as transport.
Exosoms can be represented as microscopic parcels in the membrane shell. The cells release them outward, and other cells can absorb the contents. Inside such bubbles may be proteins, RNA and other molecules. For medicine, exosomes are interesting as a delivery system: they are small enough, naturally participate in intercellular metabolism and can transfer useful instructions to the necessary tissues.
The team, led by Zhenming Kang and Gochao Zhu, first prepared HEK293T cells in the lab. These cells were forced to produce matrix RNA HSP70. Matrix RNA works as an instruction: once in a cage, it tells her what protein you need to collect. In this case, it was HSP70, which should help neurons and related cells cope with the consequences of prolonged sleep deprivation.
To direct exosomes to the brain, the researchers added to them the protein RVG-Lamp2b. The result was HSP70@ExoRVG particles. Then the scientists checked their size, shape and protein composition. To do this, using translucent electron microscopy, analysis of nanoparticle trajectories and western-blotting, a laboratory method for detecting specific proteins.
After checking the particles, the researchers moved on to cellular and animal experiments. They first studied whether the new exosomes are absorbing neural progenitor cells. This is called immature cells of the nervous system, which can turn into different types of nerve cells. In the laboratory culture, exosomes successfully delivered matrix RNA HSP70, and the level of a protective protein increased inside the cells.
Then the scientists tested therapy on mice, which were subjected to chronic lack of sleep. One animal was injected with exosomes with HSP70 and a brain “address” of RVG, the other – ordinary or empty exosomes. After that, the researchers evaluated memory, learning, and molecular signs of inflammation in the brain.
The mice that received HSP70@ExoRVG better coped with memory tasks and learning after a period of lack of sleep. In the hippocampus, the area of the brain important for memory, the levels of inflammatory molecules TNF-α, IL-6 and IL-1β have decreased. At the same time, the level of IL-10, a signaling molecule with an anti-inflammatory effect, increased.
Treatment also affected the molecules associated with the restoration and operation of the nervous tissue. In mice, the levels of BDNF, a protein that supports growth, survival, and neuron health, has increased. The level of phosphorylated CREB has also increased. This molecule is involved in processes related to memory and learning. According to the authors, the exosomes used better than empty or non-brain particles.
The point of approach is not just to “compensate” a sleepless night. Chronic lack of sleep starts inflammatory processes, which, with prolonged exposure, can increase the risk of disorders in the nervous system. Therefore, the researchers consider the exosome delivery of HSP70 as a possible path to the treatment of conditions, where lack of sleep is associated with neuroinflammation and gradual deterioration of the brain.
While the work remains an early experiment. Before human trials, you will need to check the safety, dosage, duration of the effect and possible adverse reactions. But the study shows an important principle: exosomes can be used not only to deliver small RNAs, but also to transfer matrix RNAs that causes brain cells to produce a protective protein.
The authors believe that for the first time showed the successful delivery of mRNA with the help of RVG-modified exos for disorders caused by sleep deprivation. The next step is to understand how stable the effect will be in different models of chronic sleep shortages and whether it is possible to turn the laboratory scheme into a safe therapy.
The lack of sleep beats not only in the mood and attention. When a lack of sleep lasts for a long time, the brain begins to work in the mode of chronic stress: inflammation increases, memories are worse fixed, learning and decision-making suffers worse. Chinese researchers have tested a new way to mitigate these effects in mice. Instead of conventional medicine, they used exosomes - tiny bubbles through which cells transmit each other biological molecules.
The work was carried out by the team of the First Cuanzhou Hospital, associated with Fujian Medical University. The researchers tried to deliver the heat shock protein HSP70 to the brain. This protein helps cells experience stress, protects protein structures from damage and improper folding. The problem is that the brain is protected by a blood-brain barrier: many substances do not pass from the blood to the nervous tissue. Therefore, scientists decided to use exosomes as transport.
Exosoms can be represented as microscopic parcels in the membrane shell. The cells release them outward, and other cells can absorb the contents. Inside such bubbles may be proteins, RNA and other molecules. For medicine, exosomes are interesting as a delivery system: they are small enough, naturally participate in intercellular metabolism and can transfer useful instructions to the necessary tissues.
The team, led by Zhenming Kang and Gochao Zhu, first prepared HEK293T cells in the lab. These cells were forced to produce matrix RNA HSP70. Matrix RNA works as an instruction: once in a cage, it tells her what protein you need to collect. In this case, it was HSP70, which should help neurons and related cells cope with the consequences of prolonged sleep deprivation.
To direct exosomes to the brain, the researchers added to them the protein RVG-Lamp2b. The result was HSP70@ExoRVG particles. Then the scientists checked their size, shape and protein composition. To do this, using translucent electron microscopy, analysis of nanoparticle trajectories and western-blotting, a laboratory method for detecting specific proteins.
After checking the particles, the researchers moved on to cellular and animal experiments. They first studied whether the new exosomes are absorbing neural progenitor cells. This is called immature cells of the nervous system, which can turn into different types of nerve cells. In the laboratory culture, exosomes successfully delivered matrix RNA HSP70, and the level of a protective protein increased inside the cells.
Then the scientists tested therapy on mice, which were subjected to chronic lack of sleep. One animal was injected with exosomes with HSP70 and a brain “address” of RVG, the other – ordinary or empty exosomes. After that, the researchers evaluated memory, learning, and molecular signs of inflammation in the brain.
The mice that received HSP70@ExoRVG better coped with memory tasks and learning after a period of lack of sleep. In the hippocampus, the area of the brain important for memory, the levels of inflammatory molecules TNF-α, IL-6 and IL-1β have decreased. At the same time, the level of IL-10, a signaling molecule with an anti-inflammatory effect, increased.
Treatment also affected the molecules associated with the restoration and operation of the nervous tissue. In mice, the levels of BDNF, a protein that supports growth, survival, and neuron health, has increased. The level of phosphorylated CREB has also increased. This molecule is involved in processes related to memory and learning. According to the authors, the exosomes used better than empty or non-brain particles.
The point of approach is not just to “compensate” a sleepless night. Chronic lack of sleep starts inflammatory processes, which, with prolonged exposure, can increase the risk of disorders in the nervous system. Therefore, the researchers consider the exosome delivery of HSP70 as a possible path to the treatment of conditions, where lack of sleep is associated with neuroinflammation and gradual deterioration of the brain.
While the work remains an early experiment. Before human trials, you will need to check the safety, dosage, duration of the effect and possible adverse reactions. But the study shows an important principle: exosomes can be used not only to deliver small RNAs, but also to transfer matrix RNAs that causes brain cells to produce a protective protein.
The authors believe that for the first time showed the successful delivery of mRNA with the help of RVG-modified exos for disorders caused by sleep deprivation. The next step is to understand how stable the effect will be in different models of chronic sleep shortages and whether it is possible to turn the laboratory scheme into a safe therapy.
