EXTL2 and EXTL3 inhibition with siRNAs as a promising substrate reduction therapy for Sanfilippo C syndrome

• Published in: Scientific reports 2015-09, Vol.5 (1), p.13654-13654, Article 13654
• Main Authors: Canals, Isaac, Benetó, Noelia, Cozar, Mónica, Vilageliu, Lluïsa, Grinberg, Daniel
• Format: Article
• Language: English
• Subjects: 631/208/199; 631/337/505; Fibroblasts; Fibroblasts - metabolism; Gene Expression; Genetic diseases; Genètica molecular humana; Glycosaminoglycans - metabolism; Heparan sulfate; Heparitin Sulfate - metabolism; Human molecular genetics; Humanities and Social Sciences; Humans; Immunocytochemistry; Immunohistochemistry; Lysosomes; Malalties hereditàries; Malalties neurodegeneratives; Membrane Proteins - genetics; Membrane Proteins - metabolism; Mucopolysaccharidosis III - genetics; Mucopolysaccharidosis III - metabolism; Mucopolysaccharidosis III - therapy; multidisciplinary; Mutació (Biologia); Mutation (Biology); N-Acetylglucosaminyltransferases - genetics; N-Acetylglucosaminyltransferases - metabolism; Neurodegeneration; Neurodegenerative diseases; Neurological diseases; Reversion; RNA Interference; RNA, Messenger - genetics; RNA, Small Interfering - genetics; Science; siRNA; Sulfates; Terapèutica; Therapeutics; Transfection
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep13654

Sanfilippo syndrome is a rare lysosomal storage disorder caused by an impaired degradation of heparan sulfate (HS). It presents severe and progressive neurodegeneration and currently there is no effective treatment. Substrate reduction therapy (SRT) may be a useful option for neurological disorders of this kind and several approaches have been tested to date. Here we use different siRNAs targeting EXTL2 and EXTL3 genes, which are important for HS synthesis, as SRT in Sanfilippo C patients’ fibroblasts in order to decrease glycosaminoglycan (GAG) storage inside the lysosomes. The results show a high inhibition of the EXTL gene mRNAs (around 90%), a decrease in GAG synthesis after three days (30–60%) and a decrease in GAG storage after 14 days (up to 24%). Moreover, immunocytochemistry analyses showed a clear reversion of the phenotype after treatment. The in vitro inhibition of HS synthesis genes using siRNAs shown here is a first step in the development of a future therapeutic option for Sanfilippo C syndrome.