Researchers at EARA member the University of Antwerp, Belgium, together with international collaborators, have studied how a common bacterial protein in the gut can affect the immune system. 

A protein, known as curli, is produced by gut bacteria to help them stick to surfaces. These bacteria, commonly referred to as the gut microbiome, only recently have been shown to have a direct effect on nerve cells.

The team exposed gut nerve cells in cultures to the curli protein and also tested its effects in live mice by injecting it into their colon walls. They noted that the curli could cause inflammation in specialised nerve cells, called glial cells, which are essential for the support of the nervous system. 

This inflammation then increased the production of a protein called Serum Amyloid A3 (SAA3), which is involved in the body’s early defense system against infections. 

Leader of the study, Peter Verstraelen, said: “This study highlights the critical role of SAA3 in gut inflammation caused by bacterial proteins.”

The gut microbiome is believed to play a crucial part in the development of degenerative brain diseases (such as Alzheimer’s and Parkinson’s), although the mechanisms remain unclear. 

The team will now further investigate whether this protein enters the bloodstream and the brain, where it could affect the progression of dementia.