Hypomorphic Smn knockdown C2C12 myoblasts reveal intrinsic defects in myoblast fusion and myotube morphology

Shafey, Dina; Côté, Patrice D.; Kothary, Rashmi

doi:10.1016/j.yexcr.2005.08.019

Cited by 96 publications

(81 citation statements)

References 37 publications

(37 reference statements)

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“…Evidence from several in vitro and animal studies supports this hypothesis. Primary motor neurons isolated from SMA mice have been shown to have morphological abnormalities of distal termini with shortened axonal length and small growth cones (17), while SMA patient-derived myoblasts and Smn-deficient C2C12 myoblasts show impairment of myofiber proliferation and fusion (46,47). Coculture of satellite cells derived from SMA patients with motor neurons causes premature motor neuron disorganization and death, suggesting a failure of trophic support by SMA muscle for motor nerves (48).…”

Section: Discussionmentioning

confidence: 99%

Trichostatin A increases SMN expression and survival in a mouse model of spinal muscular atrophy

Avila¹,

Burnett²,

Taye³

et al. 2007

J. Clin. Invest.

317

302

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The inherited motor neuron disease spinal muscular atrophy (SMA) is caused by mutation of the telomeric survival motor neuron 1 (SMN1) gene with retention of the centromeric SMN2 gene. We sought to establish whether the potent and specific hydroxamic acid class of histone deacetylase (HDAC) inhibitors activates SMN2 gene expression in vivo and modulates the SMA disease phenotype when delivered after disease onset. Single intraperitoneal doses of 10 mg/kg trichostatin A (TSA) in nontransgenic and SMA model mice resulted in increased levels of acetylated H3 and H4 histones and modest increases in SMN gene expression. Repeated daily doses of TSA caused increases in both SMN2-derived transcript and SMN protein levels in neural tissues and muscle, which were associated with an improvement in small nuclear ribonucleoprotein (snRNP) assembly. When TSA was delivered daily beginning on P5, after the onset of weight loss and motor deficit, there was improved survival, attenuated weight loss, and enhanced motor behavior. Pathological analysis showed increased myofiber size and number and increased anterior horn cell size. These results indicate that the hydroxamic acid class of HDAC inhibitors activates SMN2 gene expression in vivo and has an ameliorating effect on the SMA disease phenotype when administered after disease onset.

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Section: Discussionmentioning

confidence: 99%

Trichostatin A increases SMN expression and survival in a mouse model of spinal muscular atrophy

Avila¹,

Burnett²,

Taye³

et al. 2007

J. Clin. Invest.

317

302

View full text Add to dashboard Cite

show abstract

“…Although the mechanisms are still elusive, several observations can be considered. Lowering SMN in cultured cells alters fusion and morphology of differentiated myoblasts (Shafey et al, 2005). Ablation of the muscular SMN causes loss of regeneration by satellite cells (Nicole et al, 2003).…”

Section: Discussionmentioning

confidence: 99%

A role for protein phosphatase PP1γ in SMN complex formation and subnuclear localization to Cajal bodies

Renvoisé

Quérol

Verrier

et al. 2012

Journal of Cell Science

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SummaryThe spinal muscular atrophy (SMA) gene product SMN forms with gem-associated protein 2-8 (Gemin2-8) and unrip (also known as STRAP) the ubiquitous survival motor neuron (SMN) complex, which is required for the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs), their nuclear import and their localization to subnuclear domain Cajal bodies (CBs). The concentration of the SMN complex and snRNPs in CBs is reduced upon SMN deficiency in SMA cells. Subcellular localization of the SMN complex is regulated in a phosphorylation-dependent manner and the precise mechanisms remain poorly understood. Using co-immunoprecipitation in HeLa cell extracts and in vitro protein binding assays, we show here that the SMN complex and its component Gemin8 interact directly with protein phosphatase PP1c. Overexpression of Gemin8 in cells increases the number of CBs and results in targeting of PP1c to CBs. Moreover, depletion of PP1c by RNA interference enhances the localization of the SMN complex and snRNPs to CBs. Consequently, the interaction between SMN and Gemin8 increases in cytoplasmic and nuclear extracts of PP1c-depleted cells. Twodimensional protein gel electrophoresis revealed that SMN is hyperphosphorylated in nuclear extracts of PP1c-depleted cells and expression of PP1c restores these isoforms. Notably, SMN deficiency in SMA leads to the aberrant subcellular localization of Gemin8 and PP1c in the atrophic skeletal muscles, suggesting that the function of PP1c is likely to be affected in disease. Our findings reveal a role of PP1c in the formation of the SMN complex and the maintenance of CB integrity. Finally, we propose Gemin8 interaction with PP1c as a target for therapeutic intervention in SMA.

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“…In addition, siRNA Wizard (Invivogen, San Diego, CA) was used to design hairpin fragments: BDNF599 5Ј-TCCC-ATTACCTGGATGCCGCA AA-TCAAGAG-TTTGCGGCATCCAGGTAAT-TT-3Ј and BDNF948 5Ј-TCCC-AAGGATAGACACTTCCTGTGT-TCAAGAG-ACACAG GAAGTGTCTATCCTTTT-3Ј. LacZ siRNA (5ЈTCCC-AAATCG TCTGACCGATGATCCGT-TCAAGAGACGGATCATCGGTCAGA CGATT-TT-3Ј) was used as scrambled control sequence in these experiments (Shafey et al, 2005). LacZ siRNA construct was a gift from Dr. Robin J.…”

Section: Methodsmentioning

confidence: 99%

BDNF Is Expressed in Skeletal Muscle Satellite Cells and Inhibits Myogenic Differentiation

Mousavi¹,

Jasmin²

2006

J. Neurosci.

149

155

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In skeletal muscle, brain-derived neurotrophic factor (BDNF) has long been thought to serve as a retrograde trophic factor for innervating motor neurons throughout their lifespan. However, its localization in mature muscle fibers has remained elusive. Given the postulated roles of BDNF in skeletal muscle, we performed a series of complementary experiments aimed at defining the localization of BDNF and its transcripts in adult muscle. By reverse transcription-PCR, in situ hybridization, and immunofluorescence, we show that BDNF, along with the receptor p75 NTR , is not expressed at significant levels within mature myofibers and that it does not accumulate preferentially within subsynaptic regions of neuromuscular junctions. Interestingly, expression of BDNF correlated with that of Pax3, a marker of muscle progenitor cells, in several different adult skeletal muscles. Additionally, BDNF was expressed in Pax7ϩ satellite cells where it colocalized with p75 NTR . In complementary cell culture experiments, we detected high levels of BDNF and p75 NTR in myoblasts. During myogenic differentiation, expression of BDNF became drastically reduced. Using small interfering RNA (siRNA) technology to knock down BDNF expression, we demonstrate enhanced myogenic differentiation of myoblasts. This accelerated rate of myogenic differentiation seen in myoblasts expressing BDNF siRNA was normalized by administration of recombinant BDNF. Collectively, these findings show that BDNF plays an important regulatory function during myogenic differentiation. In addition, the expression of BDNF in satellite cells is coherent with the notion that BDNF serves a key role in maintaining the population of muscle progenitors in adult muscle.

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Hypomorphic Smn knockdown C2C12 myoblasts reveal intrinsic defects in myoblast fusion and myotube morphology

Cited by 96 publications

References 37 publications

Trichostatin A increases SMN expression and survival in a mouse model of spinal muscular atrophy

Trichostatin A increases SMN expression and survival in a mouse model of spinal muscular atrophy

A role for protein phosphatase PP1γ in SMN complex formation and subnuclear localization to Cajal bodies

BDNF Is Expressed in Skeletal Muscle Satellite Cells and Inhibits Myogenic Differentiation

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