Abstract Details

Read the abstract and find the presentation below

Full text and presentation details

E - Disease Models and Clinical Applications -> Neurologic Diseases

Successful Prenatal Delivery of a Therapeutic Antisense Oligonucleotide for Treatment of Angelman Syndrome in Mice

Type: Oral Abstract Session

Presentation Details
Session Title: Late-Breaking Abstracts I
Location: Salon H
Start Time: 5/17/2022 8:15
End Time: 5/17/2022 8:30

Introduction: Angelman Syndrome (AS) is a rare early onset neurodevelopmental disorder for which there is currently no cure. AS is caused by the absence of a functional maternally-inherited allele of the imprinted gene UBE3A. In neurons, the paternal allele is silenced by a long non-coding RNA, UBE3A antisense transcript (UBE3A-AS). Degradation of the UBE3A-AS transcript by an ASO can activate the intact paternal UBE3A allele, leading to genetic rescue of AS. We hypothesized that prenatal delivery of the ASO would result in activation of the paternal UBE3A allele in a reporter model, as well as phenotypic improvement in an AS mouse model. Methods: We bred wild-type (WT) females to Ube3a-YFP males and injected fetuses with a therapeutic ASO via two routes: intra-cerebroventricular (ICV, 14.5) or intra-amniotic (IA, E13.5). Pups were analyzed at P14 and P35 using qPCR to measure Ube3a-AS mRNA, miRNA scope for ASO distribution, and Ube3a-YFP IF to detect paternal allele expression. After confirming successful delivery, experiments were repeated in AS mice, breeding AS-/- females to WT males such that progeny would be maternal Ube3a deficient but have an intact silenced paternal allele. Behavioral analyses were performed on P35 mice alongside analysis of Ube3a-AS mRNA and UBE3A protein. Results: Both ICV and IA injections were well tolerated, with IA injection allowing a higher dose compared to ICV (Fig. 1A). ICV injection led to decreased Ube3a-AS mRNA levels in the cortex (Fig. 1B) and widespread ASO distribution in the brain by miRNA scope and Ube3a-YFP IF, particularly in cortical layers III and VI (Fig. 1C). Strikingly, IA injection also resulted in widespread ASO distribution with activation of paternal Ube3a (Fig. 1C). Available behavioral data in ICV injected AS mice suggest improvement of cognitive and motor abilities on behavioral tests such as marble burying (Fig. 2A) and accelerating rotarod (Fig. 2B-C). Conclusion: Prenatal injection of ASO into the brain results in reactivation of paternal Ube3a in cortical neurons, with improvement of the AS phenotype. Similarly widespread distribution in neurons after amniotic fluid injection supports the potential of a minimally invasive route for prenatal therapy with implications for numerous neurodevelopmental disorders.

Figure 1: 1a. Survival of in utero injection, each dot=one pregnancy. 1b. Ube3a-AS mRNA levels after ICV delivery. 1c. Paternal Ube3a-YFP reactivation after ICV delivery (column 1), IA delivery (column 2), or PBS injection (column 3). Maternal YFP (column 4) positive control. Brains stained with neuronal marker NeuN (red) and GFP (green) to detect the endogenous YFP expression.

Figure 2: Behavioral testing in wild type (WT) and Angelman syndrome (AS) mice 6 weeks after in utero injection of ASO. 2a. Marble burying, quantified as number of marbles buried out of 20. 2b. Time spent on accelerating rotarod. 2c. Change in time on rotarod between round 1 and round 2.

Maria T. Clarke1, Lea Lentz1, Laura Remesal Gomez1, Georgia Kirn1, Jasmine Wu1, Antonia Varthaliti1, Danielle Tan2, Stephan J. Sanders1, Scott Dindot3, Saul Villeda1, Tippi C. MacKenzie1

1UCSF, San Francisco, CA,2BioMarin, Marin, CA,3Texas A&M, College Station, TX
 M.T. Clarke: None.

This site uses cookies to offer you a better user experience and to analyze site traffic. By continuing to use this website, you accept our use of cookies.