A Cell System for Phenotypic Screening of Modifiers of SMN2 Gene Expression and Function

Li, Darrick K.; Tisdale, Sarah; Espinoza-Derout, Jorge; Saieva, Luciano; Lotti, Francesco; Pellizzoni, Livio

doi:10.1371/journal.pone.0071965

Cited by 13 publications

(7 citation statements)

References 68 publications

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“…Classically, SMA is regarded as a motor neuronal disease, but recent animal and hybrid models have indicated that the earliest morphological defects occur at the NMJ (32,33), indicating SMA is an NMJ disease. Because a human model to study NMJ function is lacking, we knocked down SMN mRNA by shRNA in 201B7 MYOD (201B7 MYOD -SMN KD ) to study the molecular pathology of SMA on an isogenic background (34,35). 201B7 MYOD -SMN KD iPSCs showed a significant decrease in mRNA level and a 60% decrease in SMN protein expression (Supplemental Figure 10, F and G).…”

Section: Resultsmentioning

confidence: 99%

iPSC-derived functional human neuromuscular junctions model the pathophysiology of neuromuscular diseases

Lin¹,

Yoshida²,

Li³

et al. 2019

JCI Insight

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Section: Resultsmentioning

confidence: 99%

iPSC-derived functional human neuromuscular junctions model the pathophysiology of neuromuscular diseases

Lin¹,

Yoshida²,

Li³

et al. 2019

JCI Insight

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“…For spliceosomal snRNA analysis, snRNA-specific reverse primers were used in the RT reaction according to a previous study ( 51 ). All primers and probes used in RT-qPCR and northern blot experiments were previously described ( 28 – 30 , 53 , 54 ).…”

Section: Methodsmentioning

confidence: 99%

Pharmacokinetics, pharmacodynamics, and efficacy of a small-moleculeSMN2splicing modifier in mouse models of spinal muscular atrophy

et al. 2016

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Spinal muscular atrophy (SMA) is caused by the loss or mutation of both copies of the survival motor neuron 1 (SMN1) gene. The related SMN2 gene is retained, but due to alternative splicing of exon 7, produces insufficient levels of the SMN protein. Here, we systematically characterize the pharmacokinetic and pharmacodynamics properties of the SMN splicing modifier SMN-C1. SMN-C1 is a low-molecular weight compound that promotes the inclusion of exon 7 and increases production of SMN protein in human cells and in two transgenic mouse models of SMA. Furthermore, increases in SMN protein levels in peripheral blood mononuclear cells and skin correlate with those in the central nervous system (CNS), indicating that a change of these levels in blood or skin can be used as a non-invasive surrogate to monitor increases of SMN protein levels in the CNS. Consistent with restored SMN function, SMN-C1 treatment increases the levels of spliceosomal and U7 small-nuclear RNAs and corrects RNA processing defects induced by SMN deficiency in the spinal cord of SMNΔ7 SMA mice. A 100% or greater increase in SMN protein in the CNS of SMNΔ7 SMA mice robustly improves the phenotype. Importantly, a ∼50% increase in SMN leads to long-term survival, but the SMA phenotype is only partially corrected, indicating that certain SMA disease manifestations may respond to treatment at lower doses. Overall, we provide important insights for the translation of pre-clinical data to the clinic and further therapeutic development of this series of molecules for SMA treatment.

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“…SMN depletion induces cell proliferation defects in NIH3T3 cells (Li et al, 2013; Lotti et al, 2012). We found that these defects are associated with a decrease in the proportion of cells in S phase and a corresponding increase of those in G1 (Figure S2A), akin to the effects of U7 snRNP inhibition on the cell cycle (Wagner and Marzluff, 2006).…”

Section: Resultsmentioning

confidence: 99%

SMN Is Essential for the Biogenesis of U7 Small Nuclear Ribonucleoprotein and 3′-End Formation of Histone mRNAs

Tisdale¹,

Lotti²,

Saieva³

et al. 2013

Cell Reports

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114

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Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by a deficiency in the survival motor neuron (SMN) protein. SMN mediates the assembly of spliceosomal small nuclear ribonucleoproteins (snRNPs) and possibly other RNPs. Here we investigated SMN requirement for the biogenesis and function of U7—an snRNP specialized in the 3′-end formation of replication-dependent histone mRNAs that normally are not polyadenylated. We show that SMN deficiency impairs U7 snRNP assembly and decreases U7 levels in mammalian cells. The SMN-dependent U7 reduction affects endonucleolytic cleavage of histone mRNAs leading to abnormal accumulation of 3′-extended and polyadenylated transcripts, followed by downstream changes in histone gene expression. Importantly, SMN deficiency induces defects of histone mRNA 3′-end formation in both SMA mice and human patients. These findings demonstrate that SMN is essential for U7 biogenesis and histone mRNA processing in vivo, and identify a novel RNA pathway disrupted in SMA.

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A Cell System for Phenotypic Screening of Modifiers of SMN2 Gene Expression and Function

Cited by 13 publications

References 68 publications

iPSC-derived functional human neuromuscular junctions model the pathophysiology of neuromuscular diseases

iPSC-derived functional human neuromuscular junctions model the pathophysiology of neuromuscular diseases

Pharmacokinetics, pharmacodynamics, and efficacy of a small-moleculeSMN2splicing modifier in mouse models of spinal muscular atrophy

SMN Is Essential for the Biogenesis of U7 Small Nuclear Ribonucleoprotein and 3′-End Formation of Histone mRNAs

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