5-(N-ethyl-N-isopropyl)-amiloride enhances SMN2 exon 7 inclusion and protein expression in spinal muscular atrophy cells.
Ann Neurol
; 63(1): 26-34, 2008 Jan.
Article
en En
| MEDLINE
| ID: mdl-17924536
ABSTRACT
OBJECTIVE:
Spinal muscular atrophy (SMA) is a common inherited neuromuscular disorder caused by homozygous loss of function of the survival motor neuron 1 (SMN1) gene. All SMA patients carry at least one copy of a nearly identical SMN2 gene. However, a critical nucleotide change in SMN2 results in alternative splicing and exclusion of exon 7 in the majority of SMN2 messenger RNA (mRNA), thus producing a low level of functional SMN protein. Increasing SMN protein production by promoting SMN2 exon 7 inclusion could be a therapeutic approach for SMA. It has been shown that cellular pH microenvironment can modulate pre-mRNA alternative splicing in vivo. In this study, we tested whether inhibitors of the Na+/H+ exchanger can modulate the exon 7 splicing of SMN2 mRNAMETHODS:
We treated SMA lymphoid cell lines with Na+/H+ exchanger inhibitors and then measured SMN2 exon 7 splicing by reverse transcriptase polymerase chain reaction and SMN protein production by Western blotting and immunofluorescenceRESULTS:
We found that treatment with an Na+/H+ exchanger inhibitor, 5-(N-ethyl-N-isopropyl)-amiloride (EIPA), significantly enhances SMN2 exon 7 inclusion and SMN protein production in SMA cells. In addition, EIPA increases the number of nuclear gems in SMA cells. We further explored the underlying mechanism, and our results suggest that EIPA may promote SMN2 exon 7 inclusion through upregulation of the splicing factor SRp20 in the nucleusINTERPRETATION:
Our finding that EIPA, an inhibitor of the Na+/H+ exchanger, can increase SMN protein expression in SMA cells provides a new direction for the development of drugs for SMA treatment. However, further translational studies are needed to determine whether this finding is applicable for SMA treatment or just a proof of cellular pH effect on SMN splicing.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Atrofia Muscular Espinal
/
Empalme del ARN
/
Proteínas de Unión al ARN
/
Proteína de Unión a Elemento de Respuesta al AMP Cíclico
/
Amilorida
/
Proteínas del Tejido Nervioso
Límite:
Humans
Idioma:
En
Revista:
Ann Neurol
Año:
2008
Tipo del documento:
Article
País de afiliación:
China