Under previous grant (FFC#14/2013) researchers found that the lungs of CF mice infected with Ps. aeruginosa showed higher sulphation of specific species of glycosaminoglycans (GAG), well-known constituents of the lung extracellular matrix, in comparison to non-CF mice. They also showed that two sulphataded polysaccharides (PS), competing with endogenous GAG, were efficacious in reducing inflammation and tissue damage in mouse models of Ps. aeruginosa infection. The purposes of this project will be to define how Ps. aeruginosa chronic infection and CFTR deficiency affect the levels and sulphation of specific GAG species and to carry over a pre-clinical study to optimize PS administration.