Targeted ASO-mediated Atp1a2 knockdown in astrocytes reduces SOD1 aggregation and accelerates disease onset in mutant SOD1 mice
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE196843 | GEO | 2023/11/30
REPOSITORIES: GEO
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Project description:Background. Mutations in ATP1A2 gene encoding the Na,K-ATPase α2 isoform is associated with familial hemiplegic migraine type 2 (FHM2). Migraine with aura is a known risk factor for heart disease. The Na,K-ATPase is important for cardiac function but its role for heart disease remains unknown. We hypothesized that ATP1A2 is a susceptibility gene for heart disease and aimed to assess the underlying disease mechanism. Methods and Results. Mice heterozygous for the FHM2-associated G301R mutation in the Atp1a2 gene (α2+/G301R mice) and matching wild type (WT) controls were compared. Reduced expression of the Na,K-ATPase α2 isoform and increased expression of the α1 isoform was observed in hearts from α2+/G301R mice (Western blot). Left ventricular dilation and reduced ejection fraction was shown in hearts from 8-month-old α2+/G301R mice (cardiac magnetic resonance imaging) and this was associated with reduced nocturnal blood pressure (radiotelemetry). Cardiac function and blood pressure of 3-month-old α2+/G301R mice were similar to WT mice. Amplified Na,K-ATPase-dependent Src/Ras/Erk1/2 signaling was observed in hearts from 8-month-old α2+/G301R mice and this was associated with mitochondrial uncoupling (respirometry), increased oxidative stress (malonedialdehyde measurements), and a heart failure-associated metabolic shift (hyperpolarized magnetic resonance). Mitochondrial membrane potential was similar between the groups (JC-1 dye assay). Proteomics of heart tissue further suggested amplified Src/Ras/Erk1/2 signaling and increased oxidative stress and provided the molecular basis for systolic dysfunction in 8-month-old α2+/G301R mice. Conclusions. Our findings suggest that ATP1A2 mutation leads to disturbed cardiac metabolism and reduced cardiac function mediated via Na,K-ATPase-dependent ROS signaling through the Src/Ras/Erk1/2 pathway.
2022-05-20 | PXD028952 | Pride
Project description:Antisense oligonucleotides (ASOs) are being actively investigated as potential therapeutics for a broad range of neurodegenerative diseases. While these small oligonucleotides have been effective in the clinic, many basic questions regarding ASO internalization, trafficking, and modes of enhancing delivery remain. To address these questions, we investigated how lipid nanoparticle (LNP) delivery affects ASO uptake and distribution in the brain. We show that ASOs are internalized and active in central nervous system (CNS) cell types both in vivo and in vitro. While differential cellular activity and polarization states do not affect ASO potency, encapsulating ASOs in LNPs increases ASO activity up to 100-fold in cultured CNS cells. This dramatic increase in efficacy is facilitated by the intracellular trafficking of ASOs away from lysosomes or enhanced ASO uptake, which is cell-type-specific. We assessed the translatability of these results by screening ASO-LNPs in vitro and intracerebroventricularly injecting top performing formulations in mice. ASO-LNP delivery induced a strong ASO-dependent microgliosis response in the brain revealing that LNP encapsulation cannot mask ASO-mediated toxicity. However, LNP-delivered ASOs did not downregulate mRNA levels in bulk tissue due to changes in ASO distribution. While ASOs distribute widely across the brain after bulk injection, ASO-LNPs are preferentially internalized by cells lining the blood vessels and ventricles. Consistent with our findings in cells, ASOs localize to the endolysosomal system following both ASO and ASO-LNP delivery in the brain as determined using immunoelectron microscopy. These data provide valuable insights into how LNPs regulate ASO uptake and distribution in the brain, and support further development of ASO-LNPs for treating CNS disorders.
2023-05-15 | GSE220777 | GEO
Project description:This study examined the effects of antisense oligonucleotides (ASOs) on the muscle transcriptome in a transgenic mouse model of myotonic dystrophy. Two ASOs were tested in HSALR transgenic mice. Both of the ASOs targeted mRNA from a human skeletal actin (hACTA1) transgene. This transgene contains an expanded CTG repeat in the 3M-bM-^@M-^Y untranslated region (UTR) (Mankodi et al M-bM-^@M-^\Myotonic dystrophy in transgenic mice expressing an expanded CUG repeatM-bM-^@M-^] Science 2000; 289:1769-72). ASO 445235 targeted the hACTA1 transcript in the 3M-bM-^@M-^Y UTR, downstream from the expanded repeat. ASO 190401 targeted the hACTA1 transcript in the coding region. The HSALR mice received 4 weeks of biweekly subcutaneous injections of vehicle (saline), ASO 190401, or ASO 445236 (n = 4 per group), at a dose of 25 mg/kg per injection. Wild-type mice of the same strain background received saline injections (n = 4). One week after the final injection, quadriceps muscle was harvested for RNA analysis. Four conditions, four arrays per condition, to compare WT and HSALR trangenic mice without treatment (saline) and to examine the effect of two oligos (vs. saline) in the HSALR transgenic mice.
2012-06-27 | E-GEOD-38962 | biostudies-arrayexpress
Project description:Recent genetic studies of ALS patients have identified several forms of ALS that are associated with mutations in RNA binding proteins. In animals or cultured cells, such defects broadly affect RNA metabolism. This raises the question of whether all forms of ALS have general effects on RNA metabolism. We tested this hypothesis in a mouse model of ALS that is transgenic for a human disease-causing mutation in the enzyme superoxide dismutase 1 (SOD1). We analyzed RNA from laser-captured spinal cord motor neuron cell bodies of the mutant SOD1 strain, comparing the RNA profile with that from a corresponding wild-type SOD1 transgenic strain. We prepared the samples from animals that were presymptomatic, but which manifested abnormalities at the cellular level that are seen in ALS, including aggregation of the mutant protein in motor neuron cell bodies and defective morphology of neuromuscular junctions, the connections between neuron and muscle. We observed only minor changes in the level and splicing of RNA in the SOD1 mutant animals as compared with wild-type, suggesting that mutant SOD1 produces the toxic effects of ALS by a mechanism that does not involve global RNA disturbance. RNA-Seq of laser microdissection of motor neuron bodies from two biological replicates each of SOD1 YFP (wildtype 592) and SOD1 G85R YFP (737) transgenic mice.
2012-12-04 | E-GEOD-38820 | biostudies-arrayexpress
Project description:Amyotrophic lateral sclerosis (ALS) is a fatal disease, characterized by the selective loss of motor neurons. Mutations in Cu/Zn superoxide dismutase (SOD1) are the second most common cause of ALS and it is now well accepted that they result in a gain of toxicity due to protein misfolding. We previously demonstrated in the SOD1G93A rat model that misfolded SOD1 exists as distinct conformers and deposits on mitochondrial subpopulations. Here, using SOD1G93A rats coupled with conformation-restricted antibodies for misfolded SOD1 (AMF7-63 and B8H10), we identified the interactomes of the mitochondrial pools of misfolded SOD1. This strategy identified binding partners that uniquely interacted with either AMF7-63- or B8H10-reactive SOD1 conformers as well as a high proportion of interactors common to both conformers. Of this latter set, we identified the E3 ubiquitin ligase TNF receptor-associated factor 6 (TRAF6) and determined that exposure of the SOD1 functional loops facilitates this interaction. However, this conformational criterion is not universally fulfilled by all SOD1 mutants and differentiates TRAF6-interacting from non-interacting SOD1 mutants. Functionally, TRAF6 stimulates mutant SOD1 polyubiquitination and aggregation. While TRAF6 E3 ubiquitin ligase activity is required for the former, it is dispensable for the latter, indicating that the polyubiquitination and aggregation of mutant SOD1 mediated by TRAF6 are independent events. We propose that misfolded SOD1 binding to TRAF6 may be relevant to ALS disease.
2020-02-24 | PXD015279 | Pride
Project description:This study examined the effects of antisense oligonucleotides (ASOs) on the muscle transcriptome in a transgenic mouse model of myotonic dystrophy. Two ASOs were tested in HSALR transgenic mice. Both of the ASOs targeted mRNA from a human skeletal actin (hACTA1) transgene. This transgene contains an expanded CTG repeat in the 3’ untranslated region (UTR) (Mankodi et al “Myotonic dystrophy in transgenic mice expressing an expanded CUG repeat” Science 2000; 289:1769-72). ASO 445235 targeted the hACTA1 transcript in the 3’ UTR, downstream from the expanded repeat. ASO 190401 targeted the hACTA1 transcript in the coding region. The HSALR mice received 4 weeks of biweekly subcutaneous injections of vehicle (saline), ASO 190401, or ASO 445236 (n = 4 per group), at a dose of 25 mg/kg per injection. Wild-type mice of the same strain background received saline injections (n = 4). One week after the final injection, quadriceps muscle was harvested for RNA analysis.
2012-06-28 | GSE38962 | GEO
Project description:The Na/K-ATPase is the specific receptor for cardiotonic steroids (CTS) such as ouabain and digoxin. At pharmacological concentrations used in the treatment of cardiac conditions, CTS inhibit the ion-pumping function of Na/K-ATPase. At much lower concentrations, in the range of those reported for endogenous CTS in the blood, they stimulate hypertrophic growth of cultured cardiac myocytes through initiation of a Na/K-ATPase-mediated and reactive oxygen species (ROS)-dependent signaling. To examine a possible effect of endogenous concentrations of CTS on cardiac structure and function in vivo, we compared mice expressing the naturally resistant Na/K-ATPase α1 and age-matched mice genetically engineered to express a mutated Na/K-ATPase α1 with high affinity for CTS. In this model, total cardiac Na/K-ATPase activity, α1, α2 and β1 protein content remained unchanged, and the cardiac Na/K-ATPase dose-response curve to ouabain shifted to the left as expected. In males aged 3–6 months, increased α1 sensitivity to CTS resulted in a significant increase of cardiac carbonylated protein content, suggesting that ROS production was elevated. A moderate but significant increase of about 15% of the heart-weight-to-tibia-length ratio, accompanied by an increase of myocyte cross-sectional area was detected. Echocardiographic analyses did not reveal any change in cardiac function, and there was no fibrosis or re-expression of the fetal gene program. RNA sequencing analysis indicated that pathways related to energy metabolism were upregulated, while those related to extracellular matrix organization were downregulated. Consistent with a functional role of the latter, an angiotensin-II challenge that triggered fibrosis in the α1r/rα2s/s mouse failed to do so in the α1s/sα2s/s. Taken together, these results are indicative of a link between circulating CTS, Na/K-ATPase α1, ROS, and physiological cardiac hypertrophy in mice under baseline laboratory conditions.
2021-03-27 | GSE169734 | GEO
Project description:Antisense oligonucleotide (ASO) has the potential to induce off-target effects due to complementary binding between the ASO and unintended RNA with a sequence similar to the target RNA. In this study, we evaluated off-target effects of gapmer ASOs, which cleave the target RNA in an RNase H-dependent manner, by introducing the ASO into human cells and performing microarray analysis. Our data indicate that gapmer ASOs induce off-target effects depending on the degree of complementarity between the ASO and off-target candidate genes. Based on our results, we also propose a scheme for assessment of off-target effects of gapmer ASOs.
2021-12-08 | GSE190473 | GEO
Project description:Recent genetic studies of ALS patients have identified several forms of ALS that are associated with mutations in RNA binding proteins. In animals or cultured cells, such defects broadly affect RNA metabolism. This raises the question of whether all forms of ALS have general effects on RNA metabolism. We tested this hypothesis in a mouse model of ALS that is transgenic for a human disease-causing mutation in the enzyme superoxide dismutase 1 (SOD1). We analyzed RNA from laser-captured spinal cord motor neuron cell bodies of the mutant SOD1 strain, comparing the RNA profile with that from a corresponding wild-type SOD1 transgenic strain. We prepared the samples from animals that were presymptomatic, but which manifested abnormalities at the cellular level that are seen in ALS, including aggregation of the mutant protein in motor neuron cell bodies and defective morphology of neuromuscular junctions, the connections between neuron and muscle. We observed only minor changes in the level and splicing of RNA in the SOD1 mutant animals as compared with wild-type, suggesting that mutant SOD1 produces the toxic effects of ALS by a mechanism that does not involve global RNA disturbance.
2012-12-04 | GSE38820 | GEO
Project description:Antisense oligonucleotides (ASOs) are short synthetic nucleic acids that recognize and bind to complementary RNA to modulate gene expression. It is well-established that single-stranded, phosphorothioate modified ASOs enter cells independent of carrier molecules, primarily via endocytic pathways, but that only a small portion of internalized ASO is released into the cytosol and/or nucleus rendering the majority of ASO as inaccessible to the targeted RNA. Identifying pathways that can increase the available ASO pool is valuable as a research tool and therapeutically. Here, we conducted a functional genomic screen for ASO activity by engineering GFP splice reporter cells and applying genome wide CRISPR gene activation. The screen can identify factors that enhance ASO splice modulation activity. Characterization of hit genes uncovered GOLGA8, a largely uncharacterized protein, as a novel positive regulator enhancing ASO activity by ~2-fold. Bulk ASO uptake is 5-fold higher in GOLGA8 overexpressing cells where GOLGA8 and ASOs are observed in the same intracellular compartments. We find GOLGA8 is highly localized to the trans-Golgi and readily detectable at the plasma membrane. Interestingly, overexpression of GOLGA8 increased activity for both splice modulation and RNase H1-dependent ASOs. Taken together, these results support a novel role for GOLGA8 in productive ASO uptake.
2022-04-26 | GSE201237 | GEO