ISS-N1 makes the first FDA-approved drug for spinal muscular atrophy

Spinal muscular atrophy (SMA) is one of the leading genetic diseases of children and infants. SMA is caused by deletions or mutations of Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, cannot compensate for the loss of SMN1 due to predominant skipping of exon 7. While various regulatory elements that modulate SMN2 exon 7 splicing have been proposed, intronic splicing silencer N1 (ISS-N1) has emerged as the most promising target thus far for antisense oligonucleotide-mediated splicing correction in SMA. Upon procuring exclusive license from the University of Massachussets Medical School in 2010, Ionis Pharmaceuticals (formerly ISIS Pharamaceuticals) began clinical development of Spinraza™ (synonyms: Nusinersen, IONIS-SMNRX, ISIS-SMNRX), an antisense drug based on ISS-N1 target. Spinraza™ showed very promising results at all steps of the clinical development and was approved by US Food and Drug Administration (FDA) on December 23, 2016. Spinraza™ is the first FDA-approved treatment for SMA and the first antisense drug to restore expression of a fully functional protein via splicing correction. The success of Spinraza™ underscores the potential of intronic sequences as promising therapeutic targets and sets the stage for further improvement of antisense drugs based on advanced oligonucleotide chemistries and delivery protocols

Effective Brief-Writing for California Appellate Courts

This Article suggests an approach to appellate brief writing that will insure compliance with the rules of court and a clear expression of the advocate\u27s position in the issues. The author describes both the specific techniques of effective brief writing and the technical format used in writing briefs for California appellate courts. Providing practical tools and techniques for the practitioner, the author argues that adherence to these techniques will significantly improve the quality of appellate practice in California

Novel Functions of the Survival Motor Neuron Protein

The Survival Motor Neuron (SMN) protein is a multi-functional protein that participates in a wide variety of critical pathways. Low levels of SMN cause spinal muscular atrophy (SMA), the most common genetic cause of infant mortality. While the role of SMN in the assembly of small nuclear ribonucleoproteins (snRNPs) has been well characterized, many of its other diverse functions have not been thoroughly explored. Here, we examine the critical role of SMN in the growth and development of male mammalian sex organs. We show that low levels of SMN in a mild mouse model of SMA cause impaired testis development, degenerated seminiferous tubules, reduced sperm count, and low fertility. Underscoring an increased requirement for SMN expression, wild type testis showed extremely high levels of SMN protein compared to other tissues. The testis phenotype is linked to increased apoptosis in seminiferous tubules and extreme perturbations in the testis transcriptome. We examine the RNA binding function of SMN by Systematic Evolution of Ligands by Exponential Enrichment (SELEX) to identify RNA sequence and structural motif(s) of SMN. Our results reveal a combination of sequence motifs and structural contexts that drive the specificity of RNA-SMN interactions. Our results of truncation and substitution experiments suggest a requirement for multiple contacts between SMN and RNA to maintain the high affinity. We demonstrate that both affinity and specificity of RNA-SMN interaction are influenced by salt concentrations. To identify in vivo RNA targets of SMN, we performed crosslinking and immunoprecipitation coupled with high-throughput sequencing (HITS-CLIP). HITS-CLIP identified a variety of RNA targets of SMN with an enrichment of mRNAs participating in a number of pathways, including ribosome function and actin cytoskeleton regulation. In order to determine whether expression levels of target RNAs are regulated by SMN, we performed knockdown of SMN levels followed by RNA-Seq. SPON2, LAMB2, and EEF1A2 in particular were all predicted by HITS-CLIP to be bound by SMN and were downregulated upon SMN knockdown, indicating a direct regulatory role for SMN on expression of these genes

Heritable Factors Play a Major Role in Determining Host Responses to \u3ci\u3eWuchereria bancrofti\u3c/i\u3e Infection in an Isolated South Pacific Island Population

Background. It is increasingly recognized that host genetic factors may play an important role in determining the outcome of filarial infections. To test this hypothesis in bancroftian lymphatic filariasis, pedigree data were collected twice during an 18-year period from an isolated Polynesian population living on a Pacific island where lymphatic filariasis is endemic. Methods. Using variance-component analysis, we examined the contribution of shared genetic and environmental effects on host clinical and immune responses to filarial infection, along with potential confounding determinants. Results. Sex was found to have a negligible influence on heritability estimates, but shared-household effects accounted for up to 32% of host variability. After accounting for these shared-household effects, heritability estimates suggested that levels of microfilariae and circulating adult worm antigen, as well as host eosinophil and immunoglobulin G antibody responses to larval and adult worm antigens, were highly heritable (range of heritability estimates, 0.15-0.84). Conclusions. These data provide evidence of a key role for genetic factors in determining the host response to filarial infections in humans and emphasize the complexity of the relationships among the host, parasite, and environment

Oxidative Stress Triggers Body-Wide Skipping of Multiple Exons of the Spinal Muscular Atrophy Gene

Humans carry two nearly identical copies of Survival Motor Neuron gene: SMN1 and SMN2. Loss of SMN1 leads to spinal muscular atrophy (SMA), the most frequent genetic cause of infant mortality. While SMN2 cannot compensate for the loss of SMN1 due to predominant skipping of exon 7, correction of SMN2 exon 7 splicing holds the promise of a cure for SMA. Previously, we used cell-based models coupled with a multi-exon-skipping detection assay (MESDA) to demonstrate the vulnerability of SMN2 exons to aberrant splicing under the conditions of oxidative stress (OS). Here we employ a transgenic mouse model and MESDA to examine the OS-induced splicing regulation of SMN2 exons. We induced OS using paraquat that is known to trigger production of reactive oxygen species and cause mitochondrial dysfunction. We show an overwhelming co-skipping of SMN2 exon 5 and exon 7 under OS in all tissues except testis. We also show that OS increases skipping of SMN2 exon 3 in all tissues except testis. We uncover several new SMN2 splice isoforms expressed at elevated levels under the conditions of OS. We analyze cis-elements and transacting factors to demonstrate the diversity of mechanisms for splicing misregulation under OS. Our results of proteome analysis reveal downregulation of hnRNP H as one of the potential consequences of OS in brain. Our findings suggest SMN2 as a sensor of OS with implications to SMA and other diseases impacted by low levels of SMN protein