Discovery and Optimization of Small Molecule Splicing Modifiers of Survival Motor Neuron 2 as a Treatment for Spinal Muscular Atrophy

Abstract

The underlying cause of spinal muscular atrophy (SMA) is a deficiency of the survival motor neuron (SMN) protein. Starting from hits identified in a high-throughput screening campaign and through structure-activity relationship investigations, we have developed small molecules that potently shift the alternative splicing of the SMN2 exon 7, resulting in increased production of the full-length SMN mRNA and protein. Three novel chemical series, represented by compounds 9, 14, and 20, have been optimized to increase the level of SMN protein by >50% in SMA patient-derived fibroblasts at concentrations of <160 nM. Daily administration of these compounds to severe SMA Δ7 mice results in an increased production of SMN protein in disease-relevant tissues and a significant increase in median survival time in a dose-dependent manner. Our work supports the development of an orally administered small molecule for the treatment of patients with SMA.

A Concise Review on the Synthesis and Reactions of Pyrazolopyrazine Heterocycles

“…Alkylation of dimethyl‐ 1H ‐pyrazole‐3,5‐dicarboxylate (131) with chloroacetone to give diethyl 1‐(2‐oxopropyl)‐ 1H ‐pyrazole‐3,5‐dicarboxylate (132) , which underwent cyclization upon reflux in ammonium acetate‐acetic acid mixture affording ethyl 4‐hydroxy‐6‐methylpyrazolo[1,5‐ a ]pyrazine‐2‐carboxylate (133) (Scheme ) .…”

A deep learning approach to identify new gene targets of a novel therapeutic for human splicing disorders

“…Several small-molecules have been developed to selectively modulate the splicing of specific pre-mRNAs, offering potential new treatments for SMA and FD 27,36,37,[42][43][44][45] . One such compound, kinetin (6-furfurylaminopurine), was previously shown to promote exon 20 inclusion in the Elongator complex protein 1 gene (ELP1, MIM: 603722) in FD 44,46 .…”

“…New therapeutic approaches aimed at correction of pre-mRNA splicing defects, including antisense oligonucleotides, splicing modulator compounds (SMCs), and modified exon-specific U1 small nuclear RNA, have shown significant promise in many diseases [27][28][29][30][31][32][33][34][35] . SMCs are attractive because they can be optimized for broad tissue distribution and are orally administered 27,36,37 . With advances in precision medicine and the capability to discover patientspecific mutations, there is strong impetus to develop new methods to predict if a drug might be beneficial in a specific patient.…”

“Characterisation of the biflavonoid hinokiflavone as a pre-mRNA splicing modulator that inhibits SENP”

“…The dysregulation of alternative splicing is now recognized as a major mechanism for multiple forms of human disease, including inherited disorders, cancer, diabetes and neurodegenerative diseases 8 . The ability to target the modulation of specific classes of alternative pre-mRNA splicing events using small molecules is thus seen as an important new therapeutic strategy for drug development and future disease therapy ( 9,10,11 ).…”