Extracellular vesicles and their diagnostic potential in amyotrophic lateral sclerosis

Advances in microfluidic chips targeting toxic aggregation proteins for neurodegenerative diseases

Neurodegenerative diseases (NDs) are characterized by nervous system damage, often influenced by genetic and aging factors. Pathological analysis frequently reveals the presence of aggregated toxic proteins. The intricate and poorly understood origins of these diseases have hindered progress in early diagnosis and drug development. The development of novel in-vitro and in-vivo models could enhance our comprehension of ND mechanisms and facilitate clinical treatment advancements. Microfluidic chips are employed to establish three-dimensional culture conditions, replicating the human ecological niche and creating a microenvironment conducive to neuronal cell survival. The incorporation of mechatronic controls unifies the chip, cells, and culture medium optimizing living conditions for the cells. This study provides a comprehensive overview of microfluidic chip applications in drug and biomarker screening for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, and amyotrophic lateral sclerosis. Our Lab-on-a-Chip system releases toxic proteins to simulate the pathological characteristics of neurodegenerative diseases, encompassing β-amyloid, α-synuclein, huntingtin, TAR DNA-binding protein 43, and Myelin Basic Protein. Investigating molecular and cellular interactions in vitro can enhance our understanding of disease mechanisms while minimizing harmful protein levels and can aid in screening potential therapeutic agents. We anticipate that our research will promote the utilization of microfluidic chips in both fundamental research and clinical applications for neurodegenerative diseases.

Exosomal microRNAs as diagnostic biomarkers and therapeutic applications in neurodegenerative diseases

Originating from slow irreversible and progressive loss and dysfunction of neurons and synapses in the nervous system, neurodegenerative diseases (NDDs) affect millions of people worldwide. Common NDDs include Parkinson's disease, Alzheimer's disease multiple sclerosis, Huntington's disease, and amyotrophic lateral sclerosis. Currently, no sensitive biomarkers are available to monitor the progression and treatment response of NDDs or to predict their prognosis. Exosomes (EXOs) are small bilipid layer-enclosed extracellular vesicles containing numerous biomolecules, including proteins, nucleic acids, and lipids. Recent evidence indicates that EXOs are pathogenic participants in the spread of neurodegenerative diseases, contributing to disease progression and spread. EXOs are also important tools for diagnosis and treatment. Recently, studies have proposed exosomal microRNAs (miRNAs) as the targets for therapies or biomarkers of NDDs. In this review, we outline the latest research on the roles of exosomal miRNAs in NDDs and their applications as potential diagnostic and therapeutic biomarkers, targets, and drugs for NDDs.

Extracellular Vesicles as Innovative Treatment Strategy for Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal motor neuron degenerative disease, and it is hard to diagnose in the early stage, and treatment means are limited, and the treatment effect is unsatisfactory. Therefore, exploring a new effective treatment strategy is urgently needed for ALS patients. Extracellular vesicles (EVs) are a heterogeneous group of natural membrane vesicles containing many bioactive substances, and they play important roles in the paracrine pathway and exhibit neuroprotection effects. A growing body of evidence shows that EVs have great application potential in diagnosis, treatment, and drug delivery in ALS, and they represent an innovative treatment strategy for ALS. In this review, we will briefly introduce the biogenesis of EVs and focus on discussing the role of EVs in ALS treatment to further enrich and boost the development of EVs as an innovative treatment strategy for ALS.

Exosomal Proteins and miRNAs as Mediators of Amyotrophic Lateral Sclerosis

Recent advances in the neurobiology and neurogenerative diseases have attracted growing interest in exosomes and their ability to carry and propagate active biomolecules as a means to reprogram recipient cells. Alterations in exosomal protein content and nucleic acid profiles found in human biological fluids have been correlated with various diseases including amyotrophic lateral sclerosis (ALS). In ALS pathogenesis, these lipid-bound nanoscale vesicles have emerged as valuable candidates for diagnostic biomarkers. Moreover, their capacity to spread misfolded proteins and functional non-coding RNAs to interconnected neuronal cells make them putative mediators for the progressive motor degeneration found remarkably apparent in ALS. This review outlines current knowledge concerning the biogenesis, heterogeneity, and function of exosomes in the brain as well as a comprehensive probe of currently available literature on ALS-related exosomal proteins and microRNAs. Lastly, with the rapid development of employing nanoparticles for drug delivery, we explore the therapeutic potentials of exosomes as well as underlying limitations in current isolation and detection methodologies.

Astrocytes & Astrocyte derived Extracellular Vesicles in Morphine Induced Amyloidopathy: Implications for Cognitive Deficits in Opiate Abusers

While opiates like morphine play a major role in the pharmacotherapy for the control of pain associated with various diseases, paradoxically, their long-term use is associated with cognitive impairments. Furthermore, morphine administration has been shown to result in neuronal synaptodendritic injury in rodent brains, leading to neurodegeneration. We recently reported the role of astrocytes as contributors of amyloidosis associated with HIV-associated neurological disorders. Herein we hypothesize that morphine could induce astrocytic amyloidosis, which, in turn, could be disseminated to various regions in the brain by astrocyte-derived EVs (ADEVs). In this study we demonstrate brain region-specific up-regulation of astrocytic amyloids in morphine dependendent rhesus macaques. In addition, herein we also demonstrate increased expression of β-site cleaving enzyme (BACE1), APP, and Aβ in human primary astrocytes (HPAs) exposed to morphine. Mechanisms involved in this process included the up-regulation of hypoxia-inducible factor (HIF-1α), its translocation and binding to the promoter of BACE1, leading to increased BACE1 activity and, generation of Aβ 1-42. Gene silencing approaches confirmed the regulatory role of HIF-1α in BACE1 mediated amyloidosis leading to astrocyte activation and neuroinflammation. We next sought to assess whether morphine-stimulated ADEVs could carry amyloid cargoes. Results showed that morphine exposure induced the release of morphine-ADEVs, carrying amyloids. Interestingly, silencing HIF-1α in astrocytes not only reduced the numbers of ADEV released, but also the packaging of amyloid cargos in the ADEVs. These findings were further validated in brain derived EVs (BEVs) isolated from macaques, wherein it was shown that BEVs from morphine-dependent macaques, carried varieties of amyloid cargoes including the cytokine IL-1β. This is the first report implicating the role of HIF-1α-BACE1 axis in morphine-mediated induction of astrocytic amyloidosis, leading, in turn, to neuroinflammation and release of the amyloid cargoes via ADEVs. These findings set the groundwork for the future development of therapeutic strategies for targeting cognitive deficits in chronic opiate users.

Diagnostic and Therapeutic Potential of Exosomal MicroRNAs for Neurodegenerative Diseases

Neurodegenerative disorders (NDs) are characterized by a gradual loss of neurons and functions that eventually leads to progressive neurological impairment. In view of the heavy burden on the healthcare system, efficient and reliable biomarkers for early diagnosis and therapeutic treatments to reverse the progression of NDs are in urgent need. There has been an increasing interest in using exosomal miRNAs as biomarkers or targeted therapies for neurological diseases recently. In this review, we overviewed the updated studies on exosomal miRNAs as biomarkers and potential therapeutic approaches in NDs, as well as their association with the pathophysiology of this group of disorders, especially Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington's disease (HD). The exosomal miRNAs that are commonly dysregulated across different NDs or are commonly used as therapeutic candidates were also identified and summarized. In summary, the feasibility of exosomal miRNAs as biomarkers and potential targeted therapy for NDs has been verified. However, due to the limitations of existing studies and the discrepancies across different studies, high quality laboratory and clinical investigations are still required.

Circulating cell-free DNA as potential diagnostic tools for amyotrophic lateral sclerosis

DNA methylation has garnered much attention in recent years for its diagnostic potential in multiple conditions including cancer and neurodegenerative diseases. Conversely, advances regarding the potential diagnostic relevance of DNA methylation status have been sparse in the field of amyotrophic lateral sclerosis (ALS) even though patients diagnosed with this condition would significantly benefit from improved molecular assays aimed at furthering the current diagnostic and therapeutic options available. This review will provide an overview of the current diagnostic approaches available for ALS diagnosis and discuss the potential clinical usefulness of DNA methylation. We will also present examples of DNA methylation as a diagnostic tool in various types of cancer and neurodegenerative conditions and expand on how circulating cfDNA methylation may be leveraged for the early detection of ALS. In general, this article will reinforce the importance of cfDNA methylation as diagnostic tools and will further highlight its clinical relevance for persons diagnosed with ALS.

Morphine-mediated release of miR-138 in astrocyte-derived extracellular vesicles promotes microglial activation

Opioids, such as morphine, are the mainstay for the management of postsurgical pain. Over the last decade there has been a dramatic increase in deaths related to opioid overdose. While opioid abuse has been shown to result in increased neuroinflammation, mechanism(s) underlying this process, remain less understood. In recent years, microRNAs have emerged as key mediators of gene expression regulating both paracrine signaling and cellular crosstalk. MiRNAs constitute the extracellular vesicle (EV) cargo and can shuttle from the donor to the recipient cells. Exposure of human primary astrocytes to morphine resulted in induction and release of miR‐138 in the EVs isolated from conditioned media of cultured astrocytes. Released EVs were, in turn, taken up by the microglia, leading to activation of these latter cells. Interestingly, activation of microglia involved binding of the GUUGUGU motif of miR138 to the endosomal toll like receptor (TLR)7, leading, in turn, to cellular activation. These findings were further corroborated in vivo in wildtype mice wherein morphine administration resulted in increased microglial activation in the thalamus. In TLR7^−/− mice on the other hand, morphine failed to induce microglial activation. These findings have ramifications for the development of EV‐loaded anti‐miRNAs as therapeutics for alleviating neuroinflammation in opioids abusers.