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Title:MODIFIED U1 RNAs AS SPLICING CORRECTORS IN HUMAN GENETIC DISORDERS
Authors:ID Pagani, Franco (Mentor) More about this mentor... New window
ID Rajkowska, Katarzyna (Author)
Files:.pdf Katarzyna_Rajkowska.pdf (13,96 MB)
MD5: B876FD57DEC865DD04C8096584188F69
 
Language:English
Work type:Doctoral dissertation
Typology:2.08 - Doctoral Dissertation
Organization:FPŠ - Graduate School
Abstract:The experimental work of this thesis was performed at the International Centre for Genetic Engineering and Biotechnology (ICGEB) in the Human Molecular Genetics Group, under the scientific direction of Prof. Franco Pagani. The project was developed during the academic years 2014-2017. Modified U1 RNAs, also named Exon Specific U1s (ExSpeU1s) represent a novel class of small RNA-based molecules that correct exons splicing defects. To evaluate their therapeutic potential focused on Familial Dysautonomia (FD), a rare autosomal recessive disorder characterized by progressive degeneration of the sensory and autonomic nervous system. More than 99% of patients are homozygous for the T to C transition in position 6 of the IKBKAP intron 20 (c.2204+6T>C). This substitution modifies the exon 20 5’ splice site (5’ss) inducing exon skipping in a tissue-specific manner and reducing the total amount of IKAP protein. The molecular mechanisms underlying the IKBKAP mis-splicing are not completely clear and there are no effective treatments. In this thesis, I investigated the therapeutic potential of ExSpeU1s and the role of cis- and trans-acting factors that regulates IKBKAP splicing. Using a splicing functional assay, I identified ExSpeU1s that bind to intron 20 sequences and rescue the exon 20 skipping defect. Interestingly, their rescue activity was modulated by several splicing factors and requires a critical exonic splicing enhancer element. Transfection experiment showed the involvement of both enhancing (TIA1, PTBP1 and PTB4) and inhibitory (SRSF3, hnRNPA1, FOX and FUS) splicing factors in IKBKAP splicing. To better evaluate the ExSpeU1s therapeutic efficacy, I transduced FD patient’s fibroblasts with a lentiviral vector expressing the most active ExSpeU1. This resulted in a complete rescue of the exon skipping defect and improvement in IKAP protein expression. Most importantly, intraperitoneal delivery of ExSpeU1s by AAV9 into a transgenic mouse model, that recapitulates the tissue-specific mis-splicing seen in FD patients, corrected the aberrant splicing patterns in several tissues increasing the amount of the corresponding IKAP protein. All together, these results identify novel regulatory splicing factors involved in the IKBKAP exon 20 regulation and provide the proof of principle that ExSpeU1s delivered in vivo by AAV vectors represent a novel therapeutic strategy for FD.
Keywords:Familial Dysautonomia, IKBKAP, IKAP, splicing, splicing defects, ExSpeU1, U1 snRNA, mouse model, AAV
Place of publishing:Nova Gorica
Year of publishing:2018
PID:20.500.12556/RUNG-3871-f1f4587e-93f8-48f9-3703-4125e49a8125 New window
COBISS.SI-ID:5129979 New window
NUK URN:URN:SI:UNG:REP:FN0JRMQX
Publication date in RUNG:26.03.2018
Views:4346
Downloads:123
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Secondary language

Language:Slovenian
Title:Modificirane molekule U1 RNA kot korektorji procesiranja RNA pri humanih genetskih boleznih
Abstract:Eskperimentalno delo je bilo opravljeno na Mednarodnem centru za genetski inženiring in biotehnologijo (International Centre fo Genetic Enginnerring and Biotechnology, ICGEB, Trst, Italija) v skupini za Humano molekularno genetiko, pod mentorstvom prof. Franco Pagani. Projekt je bil izveden v akademskem obdobju 2014-2017. Družinska disavtonomija (and. Familial Dysautonomia, FD), oz. sindrom Riley-Day, je redko avtosomalno recesivno dedno obolenje, ki je karakterizirano s progresivnim odmiranjem senzoričnega in avtonomnega živčnega sistema. Večinoma je prisotno v populaciji Ashkenazi Judov. Več kot 99% bolnikov ima hogozigotno obliko tranzicije T v C na mestu 6 introna 20 v genu IKBKAP (c.2204+6T>C). Ta nukleotidna zamenjava spremeni 5' spojitveno mesto (5'ss) eksona 20, kar povzroči tkivno-specifično izključitev eksona v prepisu gena in posledično zmanjšano količino proteina IKAP. Molekularni mehanizmi, ki povzročajo spremembe v spajanju eksonov niso popolnoma poznani. Za bolezen ne obstajajo učinkovita zdravljenja. V doktorskem delu sem raziskovala terapevtski potencial nove skupine malih RNA molekul, ki se imenujejo ekson-specifične U1 molekule (ExSpeU1) in vpliv cis- in trans-delujočih faktorjev, ki regulirajo IKBKAP spajanje eksonov. Z uporabo funkcionalne metode spajanja sem določila ExSpeU1 molekule, ki se vežejo na zaporedja introna 20 in tako popravijo izključitev eksona 20 iz prepisa gena. Ta aktivnost je regulirana z več faktorji spajanja ter zaporedjem elementa eksonskega ojačevalca spajanja. Transfekcija celičnih linij je pokazala, da so v proces spajanja IKBKAP vključeni tako ojačevalci spajanja (TIA1, PTBP1 in PTB4) ter prav tako inhibitorni faktorji (SRSF3, hnRNPA1, FOX in FUS). Z namenom boljše določitve terapevtskega potenciala ExSpeU1, sem transducirala fibroblaste, ki so bili pridobljeni iz bolnika z FD ter uporabo lentivirusnih vektorjev, ki so izražali najbolj učinkovito ExSpeU1. To je povzročilo popolno popravilo izključitve eksona in tako izboljšanje izražanja proteina IKAP. Intraperitonalni prenos ExSpeU1 z AAV9 vektorjem v transgenem mišjem modelu, ki predstavlja tkivno-specifično okvaro spajanja podobno kot pri bolnikih FD, je popravilo vzorce okvarjenega spajanja v večih tkivih in tako povečalo izražanje pripadajočega IKAP proteina. Rezultati so določili nove regulatorne faktorje spajanja, ki so udeleženi v regulaciji spajanja IKBKAP eksona 20 in tako predstavljajo potrditev načela domneve, da ExSpeU1 molekule prenesene in vivo z AAV vektorji predstavljajo ustrezno terapevstko strategijo za bolnike FD.
Keywords:Družinska disavtonomija, IKBKAP, IKAP, spajanje eksonov, napake pri spajanju, ExSpeU1, U1 snRNA, model miške, AAV


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