Alzheimer’s, cancer: a therapy based on smell to delay illness

No more pills or injections? Scientists from the University of California, Riverside (US) have revealed that smell-based therapy can be used to fight tumors, inflammatory diseases and neurodegeneration. To reach this conclusion, they carried out a study, the results of which were published in the journal eLife.

As part of this work, researchers exposed fruit flies (Drosophila melanogaster) to diacetyl, a microbial volatile compound released by yeast. The latter is present at high levels around fermenting fruits where insects spend long periods. Additionally, diacetyl is widely used in food and beverage flavorings. It occurs naturally in a variety of dairy products. Although diacetyl is found in beer, wine, Greek yogurt and many ripening fruits, inhaling it in high concentrations is considered dangerous.

Exposure to diacetyl altered gene expression in flies

Through their experiment, the team discovered that exposure to this odorous substance changed gene expression in the flies’ antennae in just a few days. This modification has even been observed in tissues lacking odorant receptors. “These molecules, to which we are exposed and are absorbed by the cells of our skin, our nose, our lungs, and probably even to the brain through the bloodstream, are capable of reaching the cell nucleus through the membrane cellular”, clarified Anandasankar Rayauthor of the research.

According to scientists, diacetyl can act as an inhibitor of histone deacetylase (HDAC) enzymes. HDAC inhibitors are used as anticancer drugs and may also be used in the treatment of inflammatory diseases as well as neurodegeneration. When HDACs, which are present in plants and animals, are inhibited, DNA wraps less compactly in cells, leading to greater gene expression. “This opens the possibility for odorant-based HDAC inhibitors to delay neurodegeneration or disease-related memory deficits.”

Childhood cancer: inhaling this volatile compound prevents the proliferation of neuroblastoma

In separate experiments, the authors found similar changes in gene expression in the lungs and brains of mice. In detail, the levels of genes upregulated in cancers such as neuroblastoma showed a significant reduction in rodents exposed to diacetyl. Same observation in human cells. Diacetyl caused higher levels of acetylation resulting in higher levels of gene expression. In further testing on human cancer cell lines, the team found that exposure to diacetyl prevented neuroblastoma proliferation.

“Our initial discovery was made using diacetyl, as a proof of concept, and this compound may not be the ideal candidate for therapy. We are already working to identify other volatile substances that cause changes in gene expression. Our important finding is that certain volatile compounds released by microbes and foods can alter the epigenetic states of neurons and other eukaryotic cells. Our report is the first report of common volatiles behaving in this way. way. This opens up a whole field of investigation. The possibilities are unlimited”concluded Anandasankar Ray.