Nanoparticles can turn off genes in bone marrow cells
Reporter : Irina Robu, PhD
MIT engineers developed an alternative to turn off specific genes which play a vital role in producing blood cells of the bone marrow using specialized nanoparticles. These nanoparticles can be made-to-order to treat heart disease or increase the yield of stem cells in patience who need stem cell transplants. The particles are coated with lipids that help stabilize them, and they can target organs such as the lungs, heart, and spleen, depending on the particles’ composition and molecular weight. This genetic therapy, also known as RNA interference is difficult to target organs other than the liver, where most of the nanoparticles tend to collect.
RNA interference is an approach that could theoretically be used to treat a variety of diseases by delivering short strands of RNA that block specific genes from being turned on in a cell. Yet, the main obstacle to this kind of therapy has been delivering it to the right part of the body. When injected into the bloodstream, nanoparticles carrying RNA tend to accrue in the liver, which various biotech companies have taken advantage of to develop new experimental treatments for liver disease.
In their recent study, scientists set out to adapt the nanoparticles so that they could reach the bone marrow which contains stem cells that produce different types of blood cells. Stimulating the process , they could enhance the yield of hematopoietic stem cells for stem cell transplantation and they created variants that have different arrangements of surface coating, polyethylene glycol. They were able to test 15 particles and determined one that was able to avoid being caught in the liver or the lungs, and that could effectively accumulate in endothelial cells of the bone marrow. They also showed that RNA carried by this particle could reduce the expression of a target gene by up to 80 percent.
The scientists then tested this approach with two genes. The first gene, SDF1 is a molecule that normally prevents hematopoietic stem cells from leaving the bone marrow. They realized that turning off the SDF1 gene could have the same effect as the drugs that are being used to induce hematopoietic stem cell release in patients who need undergo radiation treatments for blood cancers. These stem cells are later transplanted to repopulate the patient’s blood cells. By knocking down SDF1, they could boost the release of hematopoietic cells fivefold which is comparable to the levels achieved by the drugs that are now used to enhance stem cell release.
The second gene researchers use is MCP1, a molecule that plays a key role in heart disease. They realized that when MCP1 is released by bone marrow cells after a heart attack, it stimulates a flood of immune cells to leave the bone marrow and travel to the heart. Researchers realize that by delivering RNA that targets MCP1 reduced the number of immune cells that went to the heart after a heart attack.
Using these new particles, researchers hypothesized that they could further develop treatments for heart disease and other conditions.
SOURCE
https://news.mit.edu/2020/nanoparticles-bone-marrow-rnai-1005
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