title: Nonsense suppressor therapies rescue peroxisome lipid metabolism and assembly in cells from patients with specific PEX gene mutations.
abstract: Peroxisome biogenesis disorders (PBDs) are multisystemic autosomal recessive disorders resulting from mutations in PEX genes required for normal peroxisome assembly and metabolic activities. Here, we evaluated the potential effectiveness of aminoglycoside G418 (geneticin) and PTC124 (ataluren) nonsense suppression therapies for the treatment of PBD patients with disease-causing nonsense mutations. PBD patient skin fibroblasts producing stable PEX2 or PEX12 nonsense transcripts and Chinese hamster ovary (CHO) cells with a Pex2 nonsense allele all showed dramatic improvements in peroxisomal very long chain fatty acid catabolism and plasmalogen biosynthesis in response to G418 treatments. Cell imaging assays provided complementary confirmatory evidence of improved peroxisome assembly in G418-treated patient fibroblasts. In contrast, we observed no appreciable rescue of peroxisome lipid metabolism or assembly for any patient fibroblast or CHO cell culture treated with various doses of PTC124. Additionally, PTC124 did not show measurable nonsense suppression in immunoblot assays that directly evaluated the read-through of PEX7 nonsense alleles found in PBD patients with rhizomelic chondrodysplasia punctata type 1 (RCDP1). Overall, our results support the continued development of safe and effective nonsense suppressor therapies that could benefit a significant subset of individuals with PBDs. Furthermore, we suggest that the described cell culture assay systems could be useful for evaluating and screening for novel nonsense suppressor therapies.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, California, USA.
authors.forename: Patricia K
authors.initials: PK
authors.lastname: Dranchak
authors.forename: Erminia
authors.initials: E
authors.lastname: Di Pietro
authors.forename: Ann
authors.initials: A
authors.lastname: Snowden
authors.forename: Nathan
authors.initials: N
authors.lastname: Oesch
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Braverman
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Steinberg
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Hacia
mesh_terms: D000483:Alleles; D000818:Animals; D016466:CHO Cells; D018902:Chondrodysplasia Punctata, Rhizomelic / Q000378:metabolism / Q000628:therapy; D018389:Codon, Nonsense / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D005839:Gentamicins / Q000627:therapeutic use*; D006801:Humans; D050356:Lipid Metabolism / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics*; D010069:Oxadiazoles / Q000627:therapeutic use*; D000074428:Peroxisomal Biogenesis Factor 2; D018901:Peroxisomal Disorders / Q000188:drug therapy / Q000235:genetics; D000074437:Peroxisomal Targeting Signal 2 Receptor / Q000172:deficiency; D010955:Plasmalogens / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism
chemical_list: D018389:Codon, Nonsense; D005839:Gentamicins; D008565:Membrane Proteins; D010069:Oxadiazoles; C105251:PEX12 protein, human; C000614230:PEX2 protein, human; C000614269:PEX7 protein, human; D000074437:Peroxisomal Targeting Signal 2 Receptor; D010955:Plasmalogens; D018160:Receptors, Cytoplasmic and Nuclear; D000074428:Peroxisomal Biogenesis Factor 2; C010680:antibiotic G 418; C515878:ataluren