NEW YORK — The 2024 Nobel Prize in Physiology or Medicine was awarded to the discoverers of microRNAs, a class of small noncoding RNAs that play a key role in gene regulation, the Karolinska Institute announced on Monday.
The prize is shared by Victor Ambros, currently at the University of Massachusetts Chan Medical School, and Harvard Medical School’s Gary Ruvkun.
Ruvkun and Ambros' collaboration began in the late 1980s when they were postdoctoral fellows at the Massachusetts Institute of Technology, where they studied defects in Caenorhabditis elegans that impacted the timing of gene activation.
They continued this research in their own labs, collaborating to uncover a short RNA called lin-4 that did not code for any protein and appeared to inhibit another gene, dubbed lin-14, in C. elegans. They discovered that lin-4's sequence matched regions of the lin-14 gene and that it would bind to these regions to prevent lin-14 protein expression, revealing a novel mechanism of gene regulation that was mediated by a previously unknown type of RNA: microRNA.
According to the Karolinska Institute, the scientific community largely dismissed Ruvkun and Ambros' findings as a phenomenon limited to C. elegans and unlikely to have relevance in more complex animals. Later, Ruvkun discovered another microRNA called let-7 that was shown to be highly conserved throughout the animal kingdom.
In the years since, hundreds of other microRNAs have been identified and shown to be important modulators of gene expression in all multicellular organisms.
Notably, the cellular machinery used in the production of microRNAs is also involved in RNA interference (RNAi), a viral defense mechanism in plants and animals that is widely used in basic research, agriculture, and human therapeutics. Andrew Fire and Craig Mello won the Nobel Prize in Physiology or Medicine in 2006 for their discovery of RNAi.
As with RNAi, efforts are underway to find clinical applications for microRNAs. Groups have linked the small RNAs to various disorders and there has been much progress on their use in diagnostics. Work in translating microRNA research to human therapeutics has been less promising, however, with a number of companies who had been early players in the field — such as Regulus Therapeutics — struggling and others — like Rosetta Genomics, Mira Therapeutics, and Miragen Therapeutics — shutting down entirely.
In a 2005 interview with GenomeWeb, Ambros noted the growth of research linking microRNAs to various human diseases. "Whether or not they'll be used as therapeutics like siRNAs, I sort of doubt it because siRNAs are so much more effective at silencing genes than are microRNAs," he said. "However, I think that we will be able to inhibit the expression of a chosen microRNA gene. So, if a microRNA is increased in level and thereby causes a disease condition, then we can potentially use siRNA-like technology to knock down the microRNA and intervene in that fashion."