Morpholino Antisense Oligonucleotides Targeting Intronic Repressor Element1 Improve Phenotype in SMA Mouse Models

Authors
E. Y. Osman, M. R. Miller, K. L. Robbins, A. M. Lombardi, A. K. Atkinson et al.

Lab
Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, USA

Journal
Human Molecular Genetics

Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by the loss of Survival Motor Neuron-1 (SMN1). In all SMA patients a nearly identical copy gene called SMN2 is present which produces low levels of functional protein due to an alternative splicing event. To prevent exon-skipping, we have targeted an intronic repressor, Element1 (E1), located upstream of SMN2 exon 7 using Morpholino-based antisense oligonucleotides (E1MO-ASOs). A single intracerebroventricular (ICV) injection in the relatively severe mouse model of SMA (SMNΔ7 mouse model) elicited a robust induction of SMN protein and mean life span was extended from an average survival of 13 to 54 days following a single dose, consistent with large weight gains and a correction of the neuronal pathology. Additionally, E1MO-ASO treatment in an intermediate SMA mouse (SMNRT mouse model) significantly extended life span by nearly 700% and weight gain was comparable to the unaffected animals. While a number of experimental therapeutics have targeted the ISS-N1 element of SMN2 pre-mRNA, the development of E1 ASOs provides a new molecular target for SMA therapeutics that dramatically extends survival in two important pre-clinical models of disease.

BIOSEB Instruments Used:
Grip strength test (BIO-GS3)