PDF file: EURASNET Annual Report 2008

Work Package 14 Chemical Biology and TherapeuticsLead Participant: Jamal Tazideliverables: 220 Identification of novel molecules based on luciferase modelsubstrates for DMD exon 51 skipping and LMNA aberrantsplicing. (month 42)221 Validation of the efficacy of novel synthesized compoundsin model mice for: Mo-MLV, HIV-1, DMD, Breastmetastic cancer and HGPS (month 42)222 Validation of modified U7 cassetes to correct SMNexpression in a mouse model for SMA (month 42)223 Development of clinically useful drugs that direct thesplicing pathway: both Antisense olinucleotides and smallchemical molecules (month 42)224 Schümperli's group will further exploit the mouse SMAmodel mentioned above to: (i) determine the time pointwhen SMN production is critical and requires therapeuticboosting; (ii) study the ability of mutant SMN to counteractthe SMA phenotype; (iii) study the role of SMN inmotoneurons; (iv) develop ways to deliver the therapeuticU7 transgene to motoneurons. Additionally they willfurther improve their U7-based exon skipping strategy.Concerning the analysis of the role of PTB in pseudoexonsplicing, the group has just started a study to look atwhether PTB-nPTB or other neuron-specific splicingregulators affect the splicing of agrin, a protein importantfor synapse establishment and/or maintenance. (month 42)225 225 Eperon's group will investigate the possibility of usingTOES to stimulate splicing of exons damaged by mutationin cystic fibrosis (collaboration with Baralle lab) and ofundamaged skipped exons in genes with roles in thedevelopment of leukaemia. (month 42)monthplanned achieved42 on target42 on target42 on target42 on target42 on target42 on targetObjectives of the work package• Characteriziation of the five novel inhibitors of pre-mRNA splicing regarding their mode of action and molecular target• Final optimization and implementation of the high-throughput screening for inhibitors of in vitro pre-mRNA splicing usinglarge libraries (up to 100,000 compounds)• Development of indole based probes for the comprehension of their mode of interaction with SR proteins, and RNA• Compound library synthesis using alternative scaffolds-pharmacological profiling• Validation of the efficacy of novel synthesized compounds• Development of clinically useful drugs that direct the splicing pathway.Short description of activities220. Identification of novel molecules based on luciferase model substrates for DMD exon 51 skipping and LMNA aberrantsplicing "on target"As target for gene therapy, Duchenne muscular dystrophy (DMD) presents many obstacles but also unparalleled prospect forcorrection by alternative splicing. The majority of mutations in the dystrophin gene occur in the region encoding thespectrin-like central rod domain, which is largely dispensable. Exon 51 is one of the most mutated exon of encoding thespectrin-like central rod domain in DMD patients. The skipping of exon 51 can generate a shortened but in-frame transcript,permitting translation of a partially functional dystrophin protein. Tazi’s group has tested this idea using stable cell linesexpressing a luciferase reporter in which exon 51 and flanking introns were inserted in the middle of the luciferase cDNA.Because exon 51 was constitutively included between luciferase halves no luciferase activity was detected in these stable57