Project description:Constitutive heterochromatin is responsible for genome repression of DNA enriched in repetitive sequences, telomeres, and centromeres. In higher eukaryotes, constitutive heterochromatin is mostly segregated at the nuclear periphery, where the interaction with the nuclear lamina makes the genome more resistant to transcription. During physiological and pathological premature aging, heterochromatin homeostasis is profoundly compromised. Here we show that LINE-1 (L1) RNA accumulation is an early event in both typical and atypical progeroid syndromes. L1 RNA negatively regulates Suv39H1 enzymatic activity, resulting in heterochromatin loss and onset of senescent phenotypes. Depletion of L1 RNA in cells from different progeroid syndrome patients using specific antisense oligonucleotides (ASO) restores the levels of heterochromatin epigenetic marks, preserves DNA methylation and counteracts the expression of senescence-associated genes. Moreover, systemic delivery of ASO rescues the histophysiology of all tissues and increases the lifespan of Hutchinson-Gilford Progeria Syndrome (HGPS) mouse model. Furthermore, the transcriptional profiling following L1 RNA depletion shows that pathways associated with nuclear chromatin organization, cell proliferation, and transcription regulation were enriched. Similarly, pathways associated with aging, inflammatory response, innate immune response and DNA damage were downregulated. Our results show a key role of L1 RNA in heterochromatin homeostasis in progeroid syndromes and identify a possible therapeutic approach to treat premature aging and related syndromes.
Project description:Calmodulinopathies are rare inherited arrhythmia syndromes caused by dominant gain of function variants in one of three genes, CALM1, CALM2, and CALM3, which each encode the identical calmodulin (CaM) protein. We hypothesized that antisense oligonucleotide (ASO)-mediated depletion of an affected calmodulin gene would ameliorate disease manifestations, while the other two calmodulin genes would preserve CaM level and function. Here we tested this hypothesis using human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) and mouse models of CALM1 pathogenic variants. Human CALM1F142L/+ iPSC-CMs exhibited prolonged action potentials, modeling congenital long QT syndrome. CALM1-depleting ASOs did not alter CaM protein level and normalized repolarization of CALM1F142L/+ iPSC-CMs. Similarly, an ASO targeting murine Calm1 depleted Calm1 transcript without affecting CaM protein level. This ASO alleviated drug-induced arrhythmia in CalmN98S/+ mice without causing observable toxicity. These results provide proof-of-concept that ASOs targeting individual calmodulin genes are potentially effective and safe therapies for calmodulinopathies.
Project description:Mouse liver proteome was investigated upon in vivo mouse treatment with a N-acetylgalactosamine-conjugated antisense oligonucleotide engineered to silence ceramide synthase 2 specifically in hepatocytes in vivo. The data is a part of a study on the involvement of ceramide enzymatic machinery in cardiovasular disorders and its potential as a target for the disease treatment.
Project description:We used microarrays to globally profile the gene expression changes observed in liver after 3 days when dosing an antisense oligonucleotide in mice
Project description:We used microarrays to globally profile the gene expression changes observed after 3 days when transfecting an antisense oligonucleotide in 518A2 cells
Project description:In Huntington’s Disease, cellular toxicity is particularly caused by toxic protein fragments generated from the mutant huntingtin (HTT) protein. By modifying the HTT protein, we aim to reduce proteolytic cleavage and ameliorate the consequences of mutant HTT without lowering total HTT levels. To that end, we use an antisense oligonucleotide (AON) that targets HTT pre-mRNA and induces partial skipping of exon 12, which contains the critical caspase-6 cleavage site. Here, we show that AON-treatment can partially restore the phenotype of YAC128 mice, a mouse model expressing the full-length human HTT gene including 128 CAG-repeats. Wild-type and YAC128 mice were treated intracerebroventricularly with AON12.1, scrambled AON or vehicle starting at 6 months of age and followed up to 12 months of age, when MRI was performed and mice were sacrificed. AON12.1 treatment induced around 40% exon skip and protein modification. The phenotype on body weight and activity, but not rotarod, was restored by AON treatment. Genes differentially expressed in YAC128 striatum changed towards wild-type levels and striatal volume was preserved upon AON12.1 treatment. However, scrambled AON also showed a restorative effect on gene expression and appeared to generally increase brain volume.
Project description:Next generation modified antisense oligonucleotides (ASOs) are commercially approved new therapeutic modalities, yet poor productive uptake and endosomal entrapment in tumour cells limit their broad application. We compared intracellular traffic of anti KRAS antisense oligonucleotide (AZD4785) in good and poor productive uptake tumour cells, PC9 and LK2 respectively. We found that the majority of AZD4785 is rapidly delivered to CD63+ late endosomes (LE) in both cell lines. Importantly, lysobisphosphatidic acid (LBPA) that triggers ASO LE escape is presented in CD63+ LE in PC9 but not in LK2 cells. Moreover, both cells recycle AZD4785 in the extracellular vesicles (EVs) however AZD4785 quantification by advanced mass spectrometry and proteomic analysis revealed that LK2 recycles more AZD4785 and RNA-binding proteins. Finally, stimulating LBPA intracellular production or blocking EV recycling enhanced AZD4785 activity in LK2 but not in PC9 cells thus offering novel strategy to possibly enhance ASO potency in poor productive uptake tumour cells.