title: Rationally designed small molecules targeting the RNA that causes myotonic dystrophy type 1 are potently bioactive.
abstract: RNA is an important drug target, but it is difficult to design or discover small molecules that modulate RNA function. In the present study, we report that rationally designed, modularly assembled small molecules that bind the RNA that causes myotonic dystrophy type 1 (DM1) are potently bioactive in cell culture models. DM1 is caused when an expansion of r(CUG) repeats, or r(CUG)(exp), is present in the 3' untranslated region (UTR) of the dystrophia myotonica protein kinase (DMPK) mRNA. r(CUG)(exp) folds into a hairpin with regularly repeating 5'CUG/3'GUC motifs and sequesters muscleblind-like 1 protein (MBNL1). A variety of defects are associated with DM1, including (i) formation of nuclear foci, (ii) decreased translation of DMPK mRNA due to its nuclear retention, and (iii) pre-mRNA splicing defects due to inactivation of MBNL1, which controls the alternative splicing of various pre-mRNAs. Previously, modularly assembled ligands targeting r(CUG)(exp) were designed using information in an RNA motif-ligand database. These studies showed that a bis-benzimidazole (H) binds the 5'CUG/3'GUC motif in r(CUG)(exp.) Therefore, we designed multivalent ligands to bind simultaneously multiple copies of this motif in r(CUG)(exp). Herein, we report that the designed compounds improve DM1-associated defects including improvement of translational and pre-mRNA splicing defects and the disruption of nuclear foci. These studies may establish a foundation to exploit other RNA targets in genomic sequence.
authors.affiliation: The Kellogg School of Science and Engineering, Department of Chemistry, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #3A1, Jupiter, FL 33458, USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Childs-Disney
authors.forename: Jason
authors.initials: J
authors.lastname: Hoskins
authors.forename: Suzanne G
authors.initials: SG
authors.lastname: Rzuczek
authors.forename: Charles A
authors.initials: CA
authors.lastname: Thornton
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Disney
mesh_terms: D020413:3' Untranslated Regions; D017398:Alternative Splicing / Q000187:drug effects; D000818:Animals; D001562:Benzimidazoles / Q000737:chemistry* / Q000494:pharmacology*; D002460:Cell Line; D006801:Humans; D009223:Myotonic Dystrophy / Q000188:drug therapy* / Q000235:genetics; D065636:Myotonin-Protein Kinase; D059372:Nucleotide Motifs; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D012322:RNA Precursors / Q000737:chemistry / Q000235:genetics; D012326:RNA Splicing / Q000187:drug effects*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D054852:Small Molecule Libraries / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D020413:3' Untranslated Regions; D001562:Benzimidazoles; C585517:DMPK protein, human; D012322:RNA Precursors; D012333:RNA, Messenger; D054852:Small Molecule Libraries; C009712:bis-benzimidazole; D065636:Myotonin-Protein Kinase; D017346:Protein Serine-Threonine Kinases