Connecting the puzzle pieces: the role of monocytes in myelin repair
Last week, an international group of scientists published new research, adding another piece to the myelin repair puzzle.
In MS, immune cells attack the protective myelin coating around our nerve cells. When myelin becomes damaged, messages find it harder to get through – or can’t get through at all – causing the symptoms of MS.
Our brains have a natural ability to repair myelin. This involves special myelin-making cells in the brain called oligodendrocytes. These cells are made from a type of stem cell found in our brains, called oligodendrocyte progenitor cells (OPCs). But over time, this process can become less effective.
This new study was carried out by an international team of scientists based in Canada and at our Centre for MS Research in Edinburgh.
Professor Veronica Miron, one of the study's lead researchers, says:
Right now, we don’t have any approved treatments that can boost this repair process, which highlights a major gap in our understanding. That’s what motivated our research.
What did the researchers find?
Previous research has shown that a protein called Wnt (pronounced “wint”) is a key player in how well our bodies can repair myelin. But scientists haven’t yet fully understood how this protein affects myelin repair and where it comes from.
In the new study, Veronica and her colleagues identified one of the missing puzzle pieces: monocytes. These are a type of white blood cell that’s part of our immune system. We can think of them as immune system “patrollers” in our blood.
Veronica said:
We wanted to learn more about how monocytes might be helping — or hindering — this repair. We hoped to uncover new ways to support the body’s natural repair processes and bring us closer to treatments that could truly change the course of the disease.
Veronica and her team looked at how monocytes affect OPCs (the cells that actually build new myelin) in brain tissue from mice and people with MS.
They looked closely at areas where myelin was damaged and found that monocytes had entered these spots. They also discovered that monocytes released the Wnt protein. Wnt then interfered with OPCs turning into oligodendrocytes – and this had a negative impact on myelin repair.
Can blocking the signal help?
Yes — and this is an exciting breakthrough.
The researchers also found that when they switched off Wnt signal from monocytes, more OPCs were able to grow into myelin-making cells. This meant myelin repair improved in the mice.
This is a key new insight: not only do monocytes play a more harmful role than we previously thought, but Wnts are the way they do it. Connecting monocytes, Wnts, and poor repair is a major step forward in understanding how MS progresses — and how we might stop it.
What does this mean for people with MS?
This research was done in mice and on cells from people with MS, so it’s still quite a way from directly influencing MS care. But it’s an important step in understanding the biology of myelin repair. And it shows us that targeting monocytes and Wnt may be a promising approach for developing new treatments for myelin repair.
In the long run, the researchers say they hope we could also use these findings to develop a blood test that helps predict who is at higher risk for MS — and guide earlier, more personalised treatment.
Who did this research?
We’ve been funding Veronica’s work since 2015, when she was an Early Career Researcher. Since then, she has started leading her own research team – first at the University of Edinburgh and now at the University of Toronto in Canada.
She says:
Scientific research can be a slow and careful process, but every step we take builds the foundation for real change. I’m proud that the knowledge we’re generating is helping to move the field forward, and bringing us closer to treatments that could truly make a difference in the lives of people living with MS.
