T.P.42 Antisense oligonucleotide induced over-expression of progerin in human myoblasts: A possible model of muscle aging

Abstract

<h2>Abstract</h2> Antisense oligonucleotides (AOs) may be used as splice-modifying tools, with great therapeutic potential in diseases such as Duchenne muscular dystrophy and spinal muscular atrophy. They can also be used experimentally to induce specific alternative splicing patterns to produce various transcript isoforms in non-disease tissues. The aim of this study was to produce a model of accelerated muscle aging by inducing expression of the progerin isoform transcript of the lamin A gene (LMNA) in normal human myoblasts. This internally truncated transcript is missing the last 150 bases of exon 11, and gives rise to the mutant protein progerin that is associated with the lethal premature ageing disease, Hutchinson–Gilford progeria syndrome (HGPS). In HGPS, which arises from a silent de novo mutation in exon 11 of LMNA, progerin is found mostly in tissues of mesodermal origin and it has been suggested that it may also play a role in the ‘natural' ageing process in tissues. We designed 25–30 base long 2′-<i>O</i>-methyl AOs (<i>n</i>=14) targeting the donor splice site of exon 11 and acceptor site of exon 12 of LMNA and transfected primary human myoblasts with these AOs for 48h. RT-PCR showed that AOs that annealed to the area around the exon 12 donor site did induce the Δ150 lamin A transcript, but most AOs also caused a variable degree of exon 11 skipping. This contrasts with a previous study using 2′-<i>O</i>-methoxy-ethyl AOs in human fibroblasts that produced only the Δ150 lamin A transcript, and may reflect the influences of different oligomer chemistries on altered splicing. Transfection of human fibroblasts with our AOs showed similar results as with myoblasts. The present findings indicate that AO-induced over-expression of progerin in human myoblasts is possible and suggest that this may be a suitable model for studies of the role of progerin in muscle aging and sporadic inclusion body myositis in which there are features of accelerated muscle aging.