Molecular Therapy. Nucleic Acids最新文献

Mitochondrial DNA (mtDNA) base editors are powerful tools for investigating mitochondrial diseases. However, their editing efficiency can vary significantly depending on the target site within the mtDNA. In this study, we developed two improved versions of the mitochondrial adenine base editor (Hifi-sTALED and αnHifi-sTALED) by modifying components other than the TadA8e-V28R deaminase variant. These enhancements significantly increased editing efficiency while preserving minimal off-target effects across the transcriptome. Using these optimized editors, we achieved improved mtDNA editing in mouse embryos and successfully generated mt-Rnr1 mutant mice with high heteroplasmic loads. Functional analyses revealed that the mt-Rnr1 mutation impaired mitochondrial function, as indicated by reduced ATP production and decreased oxygen consumption rate (OCR). These findings demonstrate the utility of the enhanced base editors in generating mitochondrial disease models and advancing research in mitochondrial genetics.

Epigenetic modulation enables precise gene regulation without altering DNA sequences. While histone acetylation has been widely utilized for gene activation, the therapeutic potential of histone methylation remains underexplored. In this study, we developed a new epigenetic activator by fusing the histone methyltransferase SETD7 to deactivated Cas9 (dCas9). The optimized SETD7-dCas9 fusion protein successfully induced H3K4 mono-methylation and activated transcription at multiple target loci. We further established a prediction model using promoter CpG methylation status to identify genes most responsive to SETD7-dCas9-mediated activation. To evaluate therapeutic relevance, we targeted the medium-wavelength-sensitive opsin gene (OPN1MW), which is crucial for cone photoreceptor function as a strategy for treating retinitis pigmentosa. SETD7-dCas9-mediated activation of OPN1 MW restored light absorption properties comparable with rhodopsin, effectively compensating for rhodopsin deficiency in an in vitro disease model. These findings demonstrate the potential of histone methylation-based gene activation as a mutation-independent therapeutic strategy. The SETD7-dCas9 system represents a promising epigenome editing platform for precision gene regulation in diverse diseases.

[This retracts the article DOI: 10.1016/j.omtn.2020.04.018.].

The pro-inflammatory cytokine interleukin-6 (IL-6) via its IL-6 signal transducer (IL6ST/gp130) plays an important role in neuronal survival, neuro-regeneration, and pathological pain. While its critical importance in the nervous system is well established, the underlying molecular mechanisms and the involvement of microRNAs (miRNAs) as critical regulators of biological processes in health and disease are not sufficiently understood. We identified miR-486-5p as the single significantly deregulated miRNA in sensory neurons with a conditional depletion of gp130. In situ hybridization and immunofluorescence in dorsal root ganglia (DRG) localized miR-486 to small diameter neurons, including peptidergic nociceptors. miR-486^-/- mice exhibited normal baseline and neuropathic pain-like behaviors and recovered similarly to wild-type (WT) littermate controls in response to sciatic crush injury. On the other hand, DRG neurons derived from mice with a conditional deletion of IL6ST/gp130 in Na_v1.8-expressing primary afferent nociceptors (SNS-gp130^-/-) show strongly compromised neuro-regeneration, which was significantly rescued by overexpressing miR-486, indicative of a specific role of miR-486 in IL-6/gp130-dependent neuro-regenerative processes. Our findings highlight context-dependent differential expression and roles of miRNAs after nerve injury driving nerve regeneration versus neuropathic pain.

Potential strategies to develop new treatments for Parkinson's disease (PD) aim at targeting disease-associated proteins like alpha-synuclein (aSyn), which accumulates in neurons of PD patients and contributes to neuronal degeneration. A promising new approach is the therapeutic use of small interfering RNAs (siRNAs) for aSyn knockdown, but is challenging due to siRNA instability, poor delivery, and inefficient uptake. Therefore, we developed a nanoparticle-based approach for intranasal delivery of siRNAs, circumventing the blood-brain barrier and enhancing the potential of siRNAs for clinical application. Tyrosine-modified polyethylenimines (PEIs), or polypropylenimine dendrimers (PPIs), were complexed with siRNA targeting the aSyn-encoding gene SNCA (siSNCA) and combined with liposomes. Nanoparticles efficiently transfected SH-SY5Y cells with low cytotoxicity and significantly reduced SNCA mRNA levels. In Thy1-aSyn mice, intranasally administered labeled nanoparticles distributed extensively across the brain, including the olfactory bulb, substantia nigra, and prefrontal cortex. After only 4 days of treatment, siSNCA-loaded nanoparticles significantly reduced aSyn protein and SNCA mRNA levels in the brain. Mice showed neither overt adverse behavioral effects nor increased reactive microglia. These findings highlight the potential of nanoparticle-mediated intranasal siRNA delivery as a promising, non-invasive approach to reduce aSyn levels in the brain, offering a novel therapeutic strategy for Parkinson's disease.