Genistein-mediated inhibition of glycosaminoglycan synthesis as a basis for gene expression-targeted isoflavone therapy for mucopolysaccharidoses

Abstract

Mucopolysaccharidoses (MPS) are inherited, severe, progressive, metabolic disorders caused by deficiencies in different enzymes involved in degradation of glycosaminoglycans (GAGs). Although enzyme replacement therapy (ERT) has recently been available for MPS type I, and clinical trials have been performed in ERT for MPS II and MPS VI, there is little chance that this kind of treatment may be effective for neurodegenerative forms of MPS (due to inefficient delivery of enzymes to central nervous system through the blood -brain barrier), hence currently there is no effective therapy available for them. Therefore, we aim to develop an alternative therapy for these diseases. We found that genistein (4 0 ,5, 7-trihydroxyisoflavone or 5,7-dihydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) inhibits synthesis of GAGs considerably in cultures of fibroblasts of MPS patients (types I, II, IIIA and IIIB were tested). Prolonged cultivation of these cells in the presence of genistein resulted in reduction of GAG accumulation and normalization of cells as estimated by biochemical tests and electron microscopic analysis, respectively. As genistein inhibits kinase activity of epidermal growth factor receptor, which is required for full expression of genes coding for enzymes involved in GAG production, we propose to consider a substrate reduction therapy for MPS, which is referred to as 'gene expression-targeted isoflavone therapy'.

Putative Biological Mechanisms of Efficiency of Substrate Reduction Therapies for Mucopolysaccharidoses

“…Genistein at concentrations between 10 and 30 lM inhibited GAG synthesis and reduced lysosomal GAG storage (Piotrowska et al 2006). Some other flavonoids were also able to decrease GAG storage in MPS IIIA, IIIB, and VII cells (Arfi et al 2010;Piotrowska et al 2010;Kloska et al 2011).…”

“…Genistein (5, 7-dihydroxy-3-[4-hydroxyphenyl]-4H-1-benzopyran-4-one), a natural isoflavone occurring in many plants, significantly inhibited GAG synthesis when added to cultures of fibroblasts of MPS I, MPS II, MPS IIIA and MPS IIIB patients (Piotrowska et al 2006). In contrary to rhodamine B, whose detailed mechanism of action remains unknown, it was possible to learn about the way by which genistein slows the GAG synthesis down.…”

Sanfilippo syndrome type C: mutation spectrum in the heparan sulfate acetyl-CoA: α-glucosaminide N-acetyltransferase (HGSNAT) gene

“…If the expression studies confirm this hypothesis, active site-specific inhibitors of the enzyme could be tested for their ability to stabilize the mutants and modify their conformation closer to that of the wild-type enzyme, increasing the level of their residual activity as has been demonstrated for other lysosomal enzymes (reviewed in Fan [2003]; Desnick [2004]). Together with the inhibitors of heparan sulfate synthesis [Piotrowska et al, 2006;Jakó bkiewicz-Banecka et al, 2007], such ''pharmacological chaperones'' may be an interesting subject of future research in this area.…”

Impairment of glycosaminoglycan synthesis in mucopolysaccharidosis type IIIA cells by using siRNA: a potential therapeutic approach for Sanfilippo disease

“…3,4 Moreover, treatment of MPS IIIA mice with rhodamine B resulted in a behavioral improvement, 5 and pilot clinical studies with the use of a genisteinrich extract for treatment of MPS IIIA and MPS IIIB human patients showed statistically significant improvement is all tested parameters, including cognitive functions. 6 The improvement in the CNS functions in both mice and humans treated with inhibitors of GAG synthesis (either rhodamine B or genistein) were proposed to be due to a possibility of crossing the blood-brain barrier by these small molecules, and indicated that impairment of substrate production may be an effective therapeutic option for patients suffering from neuronopathic forms of lysosomal storage diseases.…”