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Microbiome Linked to Multiple Sclerosis

Multiple sclerosis affects millions of people worldwide, but the underlying cause and triggering factors remain unknown. Now scientists are looking to the gut microbiome for answers.

In multiple sclerosis (MS), the immune system attacks the myelin coating that surrounds the axons connecting nerve cells. The resulting damage leads to symptoms, such as muscle weakness, fatigue, and vision problems.

While the cause of MS is unknown, researchers have hypothesized that gut bacteria might play a crucial role.

Emerging evidence shows that the gut microbiome is an important factor underlying a variety of conditions including heart disease, cancer, metabolic disease, and mental health.

The gut-brain link goes beyond mood disorders, however, and research has linked gut microbiome dysbiosis to Parkinson’s disease and, more recently, the development of MS.

A new study published in the journal Science Translational Medicine now suggests that the gut may trigger the harmful immune response that causes the myelin damage (called demyelination) in MS.

The study’s authors previously looked at how specialized immune cells (T and B cells) communicate with each other to set off demyelination.

In the current study, the researchers identified other T-cell activation pathways. They found that a protein called GDP-L-fucose synthase is produced by certain gut bacteria in the intestines of people with MS and can activate T cells.

In one particular group of people with MS who have the HLA-DRB3* genetic variant, the gut microbiome appeared to play a much greater role in triggering demyelination than previously suspected.

The scientists hope that this new information can be used to develop better MS treatments.

Current therapies target the whole immune system, which means that, while helping counteract the harmful damage that causes MS, it also weakens helpful immune responses.

The research team hopes to be able to use GDP-L-fucose synthase to target harmful MS-specific T cells, while leaving the rest of the helpful immune response intact.

Reference:

Planas, R., et al. (2018). GDP-l-fucose synthase is a CD4+ T cell–specific autoantigen in DRB3* 02: 02 patients with multiple sclerosis. Science translational medicine, 10(462), eaat4301.