Polyglutamine-Specific Gold Nanoparticle Complex Alleviates Mutant Huntingtin-Induced Toxicity

Selenium Nanoparticles as Neuroprotective Agents: Insights into Molecular Mechanisms for Parkinson's Disease Treatment

Oxidative stress and the accumulation of misfolded proteins in the brain are the main causes of Parkinson's disease (PD). Several nanoparticles have been used as therapeutics for PD. Despite their therapeutic potential, these nanoparticles induce multiple stresses upon entry. Selenium (Se), an essential nutrient in the human body, helps in DNA formation, stress control, and cell protection from damage and infections. It can also regulate thyroid hormone metabolism, reduce brain damage, boost immunity, and promote reproductive health. Selenium nanoparticles (Se-NPs), a bioactive substance, have been employed as treatments in several disciplines, particularly as antioxidants. Se-NP, whether functionalized or not, can protect mitochondria by enhancing levels of reactive oxygen species (ROS) scavenging enzymes in the brain. They can also promote dopamine synthesis. By inhibiting the aggregation of tau, α-synuclein, and/or Aβ, they can reduce the cellular toxicities. The ability of the blood-brain barrier to absorb Se-NPs which maintain a healthy microenvironment is essential for brain homeostasis. This review focuses on stress-induced neurodegeneration and its critical control using Se-NP. Due to its ability to inhibit cellular stress and the pathophysiologies of PD, Se-NP is a promising neuroprotector with its anti-inflammatory, non-toxic, and antimicrobial properties.

Unlocking the future: Precision oligonucleotide therapy for targeted treatment of neurodegenerative disorders

Neurodegenerative disorders are complex and devastating conditions of the central nervous system that profoundly impact quality of life. Given the limited treatment options available, there is a pressing need to develop novel therapeutic strategies. Oligonucleotides have emerged as key players in precision medicine for these disorders, but their potential is hindered by poor translocation across the blood-brain barrier. This review focuses on neurodegenerative disorders other than Alzheimer's and Parkinson's, which are widely reported in the literature, and aims to address the significant hurdles in oligonucleotide delivery for neurodegenerative diseases. It highlights recent advancements in CNS-targeting approaches, such as chemical conjugation, antibody-oligonucleotide conjugates, focused ultrasound, and viral and nanocarrier-based delivery systems. Each strategy's strengths and limitations are discussed, with potential solutions proposed for more effective treatments. Additionally, the review offers valuable insights into regulatory requirements and prospects for clinical translation, which are crucial for shaping the future of neurodegenerative therapies. By exploring these innovative approaches, the goal is to surmount challenges posed by the blood-brain barrier and develop more effective treatments, thereby enhancing the quality of life of the patients suffering from these debilitating conditions.

Alpha-synuclein Fibrils Inhibit Activation of the BDNF/ERK Signaling Loop in the mPFC to Induce Parkinson's Disease-like Alterations with Depression

Depression (Dep) is one of the most common concomitant symptoms of Parkinson's disease (PD), but there is a lack of detailed pathologic evidence for the occurrence of PD-Dep. Currently, the management of symptoms from both conditions using conventional pharmacological interventions remains a formidable task. In this study, we found impaired activation of extracellular signal-related kinase (ERK), reduced levels of transcription and translation, and decreased expression of brain-derived neurotrophic factor (BDNF) in the medial prefrontal cortex (mPFC) of PD-Dep rats. We demonstrated that the abnormal phosphorylation of α-synuclein (pS129) induced tropomyosin-related kinase receptor type B (TrkB) retention at the neuronal cell membrane, leading to BDNF/TrkB signaling dysfunction. We chose SEW2871 as an ameliorator to upregulate ERK phosphorylation. The results showed that PD-Dep rats exhibited improvement in behavioral manifestations of PD and depression. In addition, a reduction in pS129 was accompanied by a restoration of the function of the BDNF/ERK signaling loop in the mPFC of PD-Dep rats.

Decoding Nucleotide Repeat Expansion Diseases: Novel Insights from Drosophila melanogaster Studies

Drosophila melanogaster usage has provided substantial insights into the pathogenesis of several nucleotide repeat expansion diseases (NREDs), a group of genetic diseases characterized by the abnormal expansion of DNA repeats. Leveraging the genetic simplicity and manipulability of Drosophila, researchers have successfully modeled close to 15 NREDs such as Huntington's disease (HD), several spinocerebellar ataxias (SCA), and myotonic dystrophies type 1 and 2 (DM1/DM2). These models have been instrumental in characterizing the principal associated molecular mechanisms: protein aggregation, RNA toxicity, and protein function loss, thus recapitulating key features of human disease. Used in chemical and genetic screenings, they also enable us to identify promising small molecules and genetic modifiers that mitigate the toxic effects of expanded repeats. This review summarizes the close to 150 studies performed in this area during the last seven years. The relevant highlights are the achievement of the first fly-based models for some NREDs, the incorporation of new technologies such as CRISPR for developing or evaluating transgenic flies containing repeat expanded motifs, and the evaluation of less understood toxic mechanisms in NREDs such as RAN translation. Overall, Drosophila melanogaster remains a powerful platform for research in NREDs.

Advances in Gene and Cellular Therapeutic Approaches for Huntington's Disease

Huntington's disease (HD) is an inherited neurodegenerative disorder caused by the abnormal expansion of CAG trinucleotide repeats in the Huntingtin gene (HTT) located on chromosome 4. It is transmitted in an autosomal dominant manner and is characterized by motor dysfunction, cognitive decline, and emotional disturbances. To date, there are no curative treatments for HD have been developed; current therapeutic approaches focus on symptom relief and comprehensive care through coordinated pharmacological and non-pharmacological methods to manage the diverse phenotypes of the disease. International clinical guidelines for the treatment of HD are continually being revised in an effort to enhance care within a multidisciplinary framework. Additionally, innovative gene and cell therapy strategies are being actively researched and developed to address the complexities of the disorder and improve treatment outcomes. This review endeavours to elucidate the current and emerging gene and cell therapy strategies for HD, offering a detailed insight into the complexities of the disorder and looking forward to future treatment paradigms. Considering the complexity of the underlying mechanisms driving HD, a synergistic treatment strategy that integrates various factors-such as distinct cell types, epigenetic patterns, genetic components, and methods to improve the cerebral microenvironment-may significantly enhance therapeutic outcomes. In the future, we eagerly anticipate ongoing innovations in interdisciplinary research that will bring profound advancements and refinements in the treatment of HD.

Imaging of intracellular protein aggregates through plasmon-assisted clusteroluminescence

The formation of clusters in non-aromatic molecules can give rise to unconventional luminescence or clusteroluminescence. Typically containing heteroatoms without extended conjugation or aromatic rings, these molecules have drawn much attention owing to the prospects of label-free biological imaging. However, their applications have been limited due to the lack of knowledge of the underlying mechanism. Herein, we have elucidated the mechanism of clusteroluminescence from proteins, which were explicitly aggregated using plasmonic silver nanoparticles. The nanoparticles promoted protein aggregation and induced nitrile formation on the surface, which, along with other lone-pair-containing heteroatoms, contributed to enhanced emission in the visible range. Remarkably, this makes imaging of proteins possible with visible excitations, as co-factor-lacking proteins generally undergo electronic transitions only in the ultraviolet range. Furthermore, the inherent protein-aggregating behaviour of plasmonic nanoparticles was harnessed for imaging of intracellular Huntingtin protein aggregates overexpressed in HeLa cells through clusteroluminescence. Significant plasmon-enhanced and red-shifted fluorescence emission was observed, which helped in the imaging and localization of the intracellular aggregates. Density functional theory calculations and transient absorbance spectroscopy were used to probe the molecular interactions at the protein-nanoparticle interface and the charge transfer states, further elucidating the role of nanoparticles and the emission mechanism. This technique thus opens alternate avenues for label-free fluorescence bioimaging.

Recent Advancements in Nanomaterials: A Promising Way to Manage Neurodegenerative Disorders

Neurodegenerative diseases (NDs) such as dementia, Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and amyotrophic lateral sclerosis are some of the most prevalent disorders currently afflicting healthcare systems. Many of these diseases share similar pathological hallmarks, including elevated oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation, all of which contribute to the deterioration of the nervous system's structure and function. The development of diagnostic and therapeutic materials in the monitoring and treatment of these diseases remains challenging. One of the biggest challenges facing therapeutic and diagnostic materials is the blood-brain barrier (BBB). The BBB is a multifunctional membrane possessing a plethora of biochemical, cellular, and immunological features that ensure brain homeostasis by preventing the entry and accumulation of unwanted compounds. With regards to neurodegenerative diseases, the recent application of tailored nanomaterials (nanocarriers and nanoparticles) has led to advances in diagnostics and therapeutics. In this review, we provide an overview of commonly used nanoparticles and their applications in NDs, which may offer new therapeutic strategies for the prevention and treatment of neurodegenerative diseases.

Nanoparticle-Based Drug Delivery Systems: An Inspiring Therapeutic Strategy for Neurodegenerative Diseases

Neurodegenerative diseases are common, incurable neurological disorders with high prevalence, and lead to memory, movement, language, and intelligence impairments, threatening the lives and health of patients worldwide. The blood-brain barrier (BBB), a physiological barrier between the central nervous system and peripheral blood circulation, plays an important role in maintaining the homeostasis of the intracerebral environment by strictly regulating the transport of substances between the blood and brain. Therefore, it is difficult for therapeutic drugs to penetrate the BBB and reach the brain, and this affects their efficacy. Nanoparticles (NPs) can be used as drug transport carriers and are also known as nanoparticle-based drug delivery systems (NDDSs). These systems not only increase the stability of drugs but also facilitate the crossing of drugs through the BBB and improve their efficacy. In this article, we provided an overview of the types and administration routes of NPs, highlighted the preclinical and clinical studies of NDDSs in neurodegenerative diseases, and summarized the combined therapeutic strategies in the management of neurodegenerative diseases. Finally, the prospects and challenges of NDDSs in recent basic and clinical research were also discussed. Above all, NDDSs provide an inspiring therapeutic strategy for the treatment of neurodegenerative diseases.