Differential expression of matrix metalloproteinases in the serum of patients with mucopolysaccharidoses

Abstract

Mucopolysaccharidoses (MPS) represent a heterogeneous group of hereditary disorders, characterized by accumulation of glycosaminoglycans within the lysosomes. The objective of this study was to elucidate the expression and activity of matrix metalloproteinases (MMPs) in the serum of pediatric patients with MPS. Serum gelatinase activity was assessed by gelatin zymography and the concentration of circulating MMP-2, MMP-9, and of tissue inhibitors of MMPs (TIMP)-1 and TIMP-2 was measured by ELISA in the serum of seven patients with MPS (five with MPS III, 1 with MPS II and 1 with MPS VI), and healthy age- and sex-matched participants. Serum activity and protein levels of MMP-9 were significantly reduced whereas of MMP-2 were significantly increased in patients with MPS III, as compared to controls. There were no significant alterations in serum protein levels of TIMP-1 and TIMP-2 in patients with MPS III, as compared to controls. In MPS II, proMMP-2 activity and protein levels of MMP-2 were significantly increased, as compared to control. In MPS VI, enzyme replacement therapy reduced the activity and protein levels of MMP-9 up to 4 months after the initiation of treatment. The reported alterations in the expression of MMPs in the serum of patients with MPS suggest that these molecules may be used as potential biomarkers for the diagnosis, follow-up and response to therapy in patients with MPS.

Fig. 1

Gelatinase activity is altered in patients with Sanfilippo disease. (a) Representative gelatine zymography in the serum of patients with MPS III (n = 5) and age- and sex-matched controls (n = 5, for each MPS III patient). (b) Quantitative analysis of gelatinolytic activity in serum of patients with MPS III and healthy controls using a computer-supported image analysis program. Each bar represents the mean ± SED from zymographies which were performed in triplicate for each patient. Statistical significance: (*) p < 0.05

Fig. 2

Gelatinase activity is increased in MPS II. (a) Representative gelatine zymography in the serum of a patient with MPS III and age- and sex-matched controls (n = 10). (b) Quantitative analysis of gelatinolytic activity in serum of a patient with MPS II and healthy controls using a computer-supported image analysis program. Each bar represents the mean ± SED from zymographies, which were performed in triplicate for each patient

Fig. 3

Enzyme replacement therapy alters gelatinase activity in MPS VI. (a) Representative gelatine zymography in the serum of a patient with MPS VI before the initiation of treatment (0), as well as 1, 2, 3, 4, and 6 months after treatment. (b–c) Quantitative analysis of gelatinolytic activity using a computer-supported image analysis program. Each bar represents the mean ± SED from zymographies which were performed in triplicate and are presented as % of the gelatinolytic activity of age- and sex-matched controls (n = 10)

Fig. 4

Concentration of circulating MMP-2 (a), MMP-9 (b), TIMP-1 (c), TIMP-2 (d), in the serum of patients with MPS III (n = 5) and age- and sex-matched controls (n = 5, for each MPS III patient) measured by ELISA. Each bar represents mean ± SED from experiments performed in duplicate. Statistical significance: (*) p < 0.05

Fig. 5

Levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 measured by ELISA in the serum of one patient with MPS II. Each bar represents the mean ± SED from experiments performed in duplicate and are presented as % of values of age- and sex-matched controls (n = 10)

Fig. 6

Enzyme replacement therapy alters protein levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 in the serum of patients with MPS VI. The protein levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured in the serum of a patient with MPS VI before the initiation of treatment (0), as well as 1, 2, 3, 4, and 6 months after treatment by ELISA. Each bar represents the mean ± SED from experiments performed in duplicate and are presented as % of values of age- and sex-matched controls (n = 10)