Protein cross-links make mucus thicker in respiratory illness patients
Sufferers of chronic respiratory illness like asthma, cystic fibrosis and chronic obstructive pulmonary disease (COPD) tend to have thicker and excessive mucus – the slimy substance which is normally produced in our bodies. Australian researchers investigating the makeup up of especially thick mucus in these people have found one of the key reasons of viscous mucus; they could also use this knowledge to develop innovative drugs that can more effectively clear mucus from the airways.
“A healthy amount of mucus is very important for capturing and clearing potential threats to the lungs, such as dust particles, dead cells and bacteria, so we’re not looking to remove mucus altogether,” explained Associate Professor Ethan Goddard-Borger from the Walter and Eliza Hall Institute (WEHI), Australia.
In the study, Goddard-Borger’s team studied long protein strands known as mucin glycoproteins, and other proteins known as trefoil factors which can influence the viscosity (thickness) of mucus. These, together with water, form the basis of mucus. The WEHI researchers were later able to demonstrate that the trefoil factors naturally adhere to the mucin glycoproteins via binding sites on their surface, which cross-link them together to make the fluid viscous.
“Within mucus, trefoil factors essentially ‘staple’ the mucin strands into a mesh: the more staples, the denser the mesh and the thicker the mucus becomes,” said Professor Goddard-Borger.
Aside from spurring deeper understanding of mucus and how it behaves in sufferers of chronic respiratory illnesses, the findings also raises the prospect of new technologies that could break down or prevent the bonds between the trefoil factors and the mucin glycoproteins.
“Developing new mucolytic drugs would make a significant impact on the quality of life and life expectancy of people struggling with debilitating respiratory conditions,” Professor Goddard-Borger concluded.
