Translational Neurodegeneration最新文献

Background: Alpha-synuclein (αSyn) is a major player in the pathophysiology of synucleinopathies, which include Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy. To date, there is no disease-modifying therapy available for these synucleinopathies. Furthermore, the intracellular mechanisms by which αSyn confers toxicity are not yet fully understood. Therefore, it is of utmost importance to investigate the pathophysiology of αSyn-induced toxicity in order to identify novel molecular targets for the development of disease-modifying therapies.

Methods: We performed the first genome-wide siRNA modifier screening in a human postmitotic neuronal cell model using αSyn-induced toxicity as a read-out. In a multi-step approach, we identified several genes, whose knockdown protected against αSyn-induced toxicity. The main hit was further validated by different methods, including immunofluorescence microscopy, qPCR, and Western blot. Furthermore, the main finding was confirmed in mouse primary neurons.

Results: The highest protection was achieved by knockdown of SNX5, which encodes the sorting nexin 5 (SNX5) protein, a component of the retromer complex. The protective efficacy of SNX5 knockdown was confirmed with an independent siRNA system. The protective effect of SNX5 knockdown was further confirmed in primary neurons from transgenic mice, where the knockdown of SNX5 led to amelioration of decrease in synchrony that was observed in untreated and control-siRNA-treated cells. SNX5 protein is a component of the SNX-BAR (Bin/Amphiphysin/Rvs) heterodimer, which is part of the retromer complex. Extracellular αSyn and overexpression of intracellular αSyn led to fragmentation of the trans-Golgi network, which was prevented by SNX5 knockdown that led to confinement of αSyn in early endosomes.

Conclusion: In summary, our data suggest that SNX5 plays an important role in the trafficking and toxicity of αSyn. Therefore, SNX5 appears to be a target of therapeutic intervention for synucleinopathies.

Background: Neurological disorders are the second leading cause of death and the leading cause of disability in the world. Thus, the development of novel disease-modifying strategies is clearly warranted. We have previously developed a therapeutic approach using mouse targeted rabies virus glycoprotein (RVG) extracellular vesicles (EVs) to deliver minicircles (MCs) expressing shRNA (shRNA-MCs) to induce long-term α-synuclein down-regulation. Although the previous therapy successfully reduced the pathology, the clinical translation was extremely unlikely since they were mouse extracellular vesicles.

Methods: To overcome this limitation, we developed a source of human RVG-EVs compatible with a personalized therapy using immature dendritic cells. Human peripheral blood monocytes were differentiated in vitro into immature dendritic cells, which were transfected to express the RVG peptide. RVG-EVs containing shRNA-MCs, loaded by electroporation, were injected intravenously in the α-synuclein performed fibril (PFF) mouse model. Level of α-synuclein, phosphorylated α-synuclein aggregates, dopaminergic neurons and motor function were evaluated 90 days after the treatment. To confirm that EVs derived from patients were suitable as a vehicle, proteomic analysis of EVs derived from control, initial and advanced Parkinson's disease was performed.

Results: The shRNA-MCs could be successfully loaded into human RVG-EVs and downregulate α-synuclein in SH-SY5Y cells. Intravenous injection of the shRNA-MC-loaded RVG-EVs induced long-term downregulation of α-synuclein mRNA expression and protein level, decreased α-synuclein aggregates, prevented dopaminergic cell death and ameliorated motor impairment in the α-synuclein PFF mouse model. Moreover, we confirmed that the EVs from PD patients are suitable as a personalized therapeutic vehicle.

Conclusion: Our study confirmed the therapeutic potential of shRNA-MCs delivered by human RVG-EVs for long-term treatment of neurodegenerative diseases. These results pave the way for clinical use of this approach.

There is increasing interest in nose-to-brain delivery as an innovative drug delivery strategy for neurodegenerative disorders such as Parkinson's or Alzheimer's disease. The unique anatomy of the nose-brain interface facilitates direct drug transport via the olfactory and trigeminal pathways to the brain, bypassing the blood-brain barrier. Different administration techniques as well as advanced drug formulations like targeted nanoparticles and thermoresponsive systems have been explored to improve the delivery efficiency and the therapeutic efficacy. This review provides an up-to-date perspective on this fast-developing field, and discusses different studies on safety and pharmacokinetic properties. A thorough evaluation of preclinical and clinical studies reveals both promises and challenges of this delivery method, highlighting approved drugs for the treatment of epilepsy and migraine that successfully utilize intranasal routes. The current landscape of research on nose-to-brain delivery is critically discussed, and a rationale is provided for ongoing research to optimize therapeutic strategies.

Background: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that begins with motor neuron death in the spinal cord and cerebral cortex, ultimately resulting in death from respiratory distress (breathing failure). About 90% of ALS cases are sporadic, and 10% of ALS cases are of the inherited type with a genetic cause. About 150 different gene mutations have been reported so far. SOD1 is a well-identified gene associated with ALS. Indeed, SOD1 aggregation has been reported in ALS patients, but the mechanism of SOD1 aggregation remains unclear. Our previous work showed that inhibiting SOD1 aggregation with a hit compound (PRG-A-01) could reduce the SOD1-induced cytotoxicity and extend the lifespan of ALS mouse model (SOD1^G93A-Tg). However, the low bioavailability and rapid degradation of the compound in vivo necessitates the development of a more effective candidate. We generated different derivatives and finally obtained the most potential drug candidate, PRG-A-04.

Methods: Neuronal cell lines were transfected with the mutant SOD1 expression vector and incubated with PRG-A-04. SOD1 aggregation was examined by SOD1 oligomerization assay, immunofluorescence and dot blot assay. The interaction between GST-conjugated SOD1 recombinant proteins and PRG-A-04 was identified using LC-MS/MS and GST pull-down assay. To check the in vivo therapeutic effect of PRG-A-04, SOD1^G93A-Tg mice were injected with PRG-A-04; then behavioral test, histological analysis and microarray were performed.

Results: PRG-A-04 demonstrated favorable pharmacokinetics including high bioavailability and significant blood-brain barrier penetration. Indeed, oral administration of PRG-A-04 in ALS mouse model inhibited the aggregation of SOD1 in the spinal cord, protected against neuronal loss, and extended the lifespan of ALS mice by up to 3 weeks. In vitro, PRG-A-04 selectively bound to the mutant form of SOD1, but not the wild type, and efficiently inhibited the aggregation caused by SOD1-G147P (a SOD1 trimer stabilizer).

Conclusions: Our findings underscore the potential of targeting trimeric SOD1 in ALS treatment, positioning PRG-A-04 as a strong drug candidate for both familial and sporadic ALS.

Stress granules (SGs) are membraneless organelles formed in the cellular cytoplasm under stressful conditions through liquid-liquid phase separation (LLPS). SG assembly can be both dependent and independent of the eIF2α pathway, whereas cellular protein quality control systems mediate SG disassembly. Chaperones and specific domains of RNA-binding proteins strongly contribute to the regulation SG dynamics. Chronic stress, arising in association with aging, may promote persistent SGs that are difficult to disassemble, thereby acting as a potential pathological nidus for protein aggregation in neurodegenerative diseases (NDDs). In this review, we discuss the dynamics of SGs and the factors involved with SG assembly and disassembly. We also highlight the relationship among LLPS, SGs, and the pathogenesis of different NDDs. More importantly, we summarize SG assembly-disassembly, which may be a double-edged sword in the pathophysiology of NDDs. This review aims to provide new insights into the biology and pathology of LLPS, SGs, and NDDs.

Background: Cytoplasmic aggregation of TAR DNA binding protein 43 (TDP-43) in neurons is one of the hallmarks of TDP-43 proteinopathy. Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) are closely associated with TDP-43 proteinopathy; however, it remains uncertain whether TDP-43 aggregation initiates the pathology or is a consequence of it.

Methods: To demonstrate the pathology of TDP-43 aggregation, we applied the optoDroplet technique in Caenorhabditis elegans (C. elegans), which allows spatiotemporal modulation of TDP-43 phase separation and assembly.

Results: We demonstrate that optogenetically induced TDP-43 aggregates exhibited insolubility similar to that observed in TDP-43 proteinopathy. These aggregates increased the severity of neurodegeneration, particularly in GABAergic motor neurons, and exacerbated sensorimotor dysfunction in C. elegans.

Conclusions: We present an optogenetic C. elegans model of TDP-43 proteinopathy that provides insight into the neuropathological mechanisms of TDP-43 aggregates. Our model serves as a promising tool for identifying therapeutic targets for TDP-43 proteinopathy.

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease that remains incurable. Although the etiologies of ALS are diverse and the precise pathogenic mechanisms are not fully understood, approximately 20% of ALS cases are caused by genetic factors. Therefore, advancing targeted gene therapies holds significant promise, at least for the 20% of ALS patients with genetic etiologies. In this review, we summarize the main strategies and techniques of current ALS gene therapies based on ALS risk genes, and review recent findings from animal studies and clinical trials. Additionally, we highlight ALS-related genes with well-understood pathogenic mechanisms and the potential of numerous emerging gene-targeted therapeutic approaches for ALS.