What you should know about MicroRNA, the Nobel Prize-winning discovery

TTwo scientists have been awarded the 2024 Nobel Prize in Physiology or Medicine for their discovery of microRNA. Victor Ambros, professor of molecular medicine at the University of Massachusetts Chan Medical School, and Gary Ruvkun, professor of genetics at Harvard Medical School and researcher at Massachusetts General Hospital, received the award for discovering how microRNAs turn genes on and off .

This isn't the first time RNA has been honored recently. The molecule has been something of a scientific darling of late: Last year, Katalin Kariko and Drew Weissman won the Nobel Prize in Physiology or Medicine for their fundamental discovery that enabled mRNA-based vaccines, a development that transformed the COVID-19 pandemic .

Here's what the discovery of microRNA means and how it can impact human health.

What is microRNA anyway?

The discovery makes it possible to manipulate which genes are activated or repressed in cells. This is crucial for controlling the production of proteins, which in turn regulate almost all body functions. It is another level of genetic control that enables the next generation of disease treatments.

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Like many scientific breakthroughs, the discovery was accidental. “It was something so unexpected that we ignored it as dirt for a while,” Ambros said during an Oct. 7 news conference. It started in 1993, when he and Ruvkun worked together as postdoctoral researchers in Massachusetts and published what they said was an interesting finding in worms that were not developing properly due to two mutations they had identified. The duo each further examined one of the genes, initially focusing on searching for aberrant proteins encoded by the mutated genes. Normally, DNA codes that make up genes lead to RNA sequences that cells then convert into proteins. For example, every cell in the human body contains exactly the same DNA sequences or blueprints – but depending on which genes are activated and which are suppressed, they take on different properties and functions.

Ambros and Ruvkun have discovered a way in which cells orchestrate this complex signal transmission: with so-called microRNAs.

To Ambrose's surprise, the end product of the mutated gene he studied was not a protein, but a tiny snippet of RNA called microRNA. Ruvkun's work on the other mutated gene showed that microRNA bound to the RNA made by his mutated gene and acted as a wrench in the protein manufacturing process, essentially blocking its production and leading to the worm's abnormal development.

The finding remained an anomaly in the world of worm research and was met with “almost deafening silence from the scientific community,” the Nobel Committee noted in its announcement. Until Ruvkun discovered another microRNA in 2000: this time one that was also found in mice, other animals and, above all, humans.

The future of microRNA

About 1,000 microRNAs have been identified in humans, and although knowledge of this field is still in its infancy, these small pieces of RNA appear to be involved in a variety of important processes, from development to basic cellular functions. Some have been linked to diseases such as cancer. Understanding how they work and how to manipulate them to turn genes on or off could potentially lead to many new therapies for countless human diseases. Researchers are already testing mircoRNA-based strategies in animals and early human studies to treat cancer and infectious diseases.

“We know from genetic research that cells and tissues do not develop normally without microRNAs. Abnormal regulation by microRNA can contribute to cancer, and mutations in genes encoding microRNAs have been found in humans, leading to conditions such as congenital hearing loss, ocular and skeletal diseases,” the Nobel Committee said. “MicroRNAs are proving to be fundamentally important for the development and function of organisms.”