title: Investigation of age-related changes in LMNA splicing and expression of progerin in human skeletal muscles.
abstract: Age-related changes in splice-forms of LMNA, which encodes the nuclear lamina proteins lamin A/C, have not been investigated in skeletal muscle. In the rare premature ageing disease, Hutchinson-Gilford progeria syndrome (HGPS), de novo point mutations in LMNA activate a cryptic splice site in exon 11, resulting in a 150 base deletion in LMNA mRNA and accumulation of a truncated protein isoform, progerin. The LMNA Δ150 progerin transcript has also been found in trace quantities in tissues of healthy people and its implication in 'natural' ageing has been proposed. We therefore investigated the expression of progerin and lamin A/C in normal human and mouse skeletal muscles of different ages. LMNA Δ150 was detected in most muscle samples from healthy individuals aged 16-71 years, but was not present in any mouse muscle samples up to the age of 18 months. Real time qPCR of human muscle samples showed that there was an age-related increase in both the full length lamin A and LMNA Δ150 transcripts, whereas their protein levels did not change significantly with age. These findings indicate that there is a basal level of mis-splicing during LMNA expression that does not change with ageing in human muscle, but at levels that do not result in increased aberrant protein. The significance of these findings in the pathophysiology of muscle ageing is uncertain and warrants further investigation.
authors.affiliation: Centre for Neuromuscular and Neurological Disorders, Australian Neuro-Muscular Research Institute Perth, Australia ; Laboratory of Neuromuscular Disorders, Department of Neurology, Qilu Hospital, Shandong University Jinan, China.
authors.forename: Yue-Bei
authors.initials: YB
authors.lastname: Luo
authors.forename: Chalermchai
authors.initials: C
authors.lastname: Mitrpant
authors.forename: Russell D
authors.initials: RD
authors.lastname: Johnsen
authors.forename: Victoria A
authors.initials: VA
authors.lastname: Fabian
authors.forename: Sue
authors.initials: S
authors.lastname: Fletcher
authors.forename: Frank L
authors.initials: FL
authors.lastname: Mastaglia
authors.forename: Steve D
authors.initials: SD
authors.lastname: Wilton
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002460:Cell Line; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D034904:Lamin Type A / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal; D008875:Middle Aged; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011371:Progeria / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D052097:Quadriceps Muscle / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: C494847:LMNA protein, human; D034904:Lamin Type A; C576142:Lmna protein, mouse; D009687:Nuclear Proteins; D020033:Protein Isoforms; D011498:Protein Precursors; D012333:RNA, Messenger; C090764:prelamin A
keywords: Human; ageing; lamin A/C; mouse; progerin; skeletal muscle