MicroRNA‑124: an emerging therapeutic target in central nervous system disorders

miR-124 mediates the effects of gut microbial dysbiosis on brain function in chronic stressed mice

The gut microbiota plays a key role in the brain function impairment caused by chronic stress, yet its exact mechanism remains unclear. Many studies have revealed the important role of miR-124 in the central nervous system. Meanwhile, previous studies have indicated that miR-124 may be regulated by chronic stress and gut microbiota. Here, we aimed to explore whether miR-124 serves as a mediator for the impacts of gut microbial dysbiosis on brain function in mice subjected to chronic stress. Repeated daily restraint stress for 4 weeks was used to induce chronic stress in mice. Chronic stress resulted in gut microbial dysbiosis, abnormal behaviors, and a decrease in hippocampal miR-124 levels. Treatment with different probiotic mixtures significantly alleviated the effects of chronic stress on hippocampal miR-124 levels and mouse behaviors. Suppression of hippocampal miR-124 expression reversed the beneficial effects of probiotics on cognitive function, neurogenesis, and related molecular markers in chronically stressed mice. Bioinformatics analysis and qPCR suggested that Ptpn11 might be a target gene for miR-124 in mediating the effects of gut microbial dysbiosis on brain function in these mice. These findings suggest that miR-124 is a pivotal regulator that mediates the detrimental effects of gut microbial dysbiosis on brain function and the subsequent cognitive impairment during chronic stress.

miRNA-124 loaded extracellular vesicles encapsulated within hydrogel matrices for combating chemotherapy-induced neurodegeneration

Chemotherapy-induced neurodegeneration represents a significant challenge in cancer survivorship, manifesting in cognitive impairments that severely affect patients' quality of life. Emerging neuroregenerative therapies offer promise in mitigating these adverse effects, with miRNA-124 playing a pivotal role due to its critical functions in neural differentiation, neurogenesis, and neuroprotection. This review article delves into the innovative approach of using miRNA-124-loaded extracellular vesicles (EVs) encapsulated within hydrogel matrices as a targeted strategy for combating chemotherapy-induced neurodegeneration. We explore the biological underpinnings of miR-124 in neuroregeneration, detailing its mechanisms of action and therapeutic potential. The article further examines the roles and advantages of EVs as natural delivery systems for miRNAs and the application of hydrogel matrices in creating a sustained release environment conducive to neural tissue regeneration. By integrating these advanced materials and biological agents, we highlight a synergistic therapeutic strategy that leverages the bioactive properties of miR-124, the targeting capabilities of EVs, and the supportive framework of hydrogels. Preclinical studies and potential pathways to clinical translation are discussed, alongside the challenges, ethical considerations, and future directions in the field. This comprehensive review underscores the transformative potential of miR-124-loaded EVs in hydrogel matrices, offering insights into their development as a novel and integrative approach for addressing the complexities of chemotherapy-induced neurodegeneration.

miR-124 coordinates metabolic regulators acting at early stages of human neurogenesis

Metabolic dysregulation of neurons is associated with diverse human brain disorders. Metabolic reprogramming occurs during neuronal differentiation, but it is not fully understood which molecules regulate metabolic changes at the early stages of neurogenesis. In this study, we report that miR-124 is a driver of metabolic change at the initiating stage of human neurogenesis. Proteome analysis has shown the oxidative phosphorylation pathway to be the most significantly altered among the differentially expressed proteins (DEPs) in the immature neurons after the knockdown of miR-124. In agreement with these proteomics results, miR-124-depleted neurons display mitochondrial dysfunctions, such as decreased mitochondrial membrane potential and cellular respiration. Moreover, morphological analyses of mitochondria in early differentiated neurons after miR-124 knockdown result in smaller and less mature shapes. Lastly, we show the potential of identified DEPs as novel metabolic regulators in early neuronal development by validating the effects of GSTK1 on cellular respiration. GSTK1, which is upregulated most significantly in miR-124 knockdown neurons, reduces the oxygen consumption rate of neural cells. Collectively, our data highlight the roles of miR-124 in coordinating metabolic maturation at the early stages of neurogenesis and provide insights into potential metabolic regulators associated with human brain disorders characterized by metabolic dysfunctions.

Diagnostic and mechanistic roles of MicroRNAs in neurodevelopmental & neurodegenerative disorders

MicroRNAs (miRNAs) are emerging as crucial elements in the regulation of gene expression, playing a significant role in the underlying neurobiology of a wide range of neuropsychiatric disorders. This review examines the intricate involvement of miRNAs in neuropsychiatric disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Fragile X syndrome (FXS), autism spectrum disorder (ASD), attention-deficit hyperactivity disorder (ADHD), Tourette syndrome (TS), schizophrenia (SCZ), and mood disorders. This review highlights how miRNA dysregulation can illuminate the molecular pathways of these diseases and potentially serve as biomarkers for early diagnosis and prognosis. Specifically, miRNAs' ability to target genes critical to the pathology of neurodegenerative diseases, their role in the development of trinucleotide repeat and neurodevelopmental disorders, and their distinctive patterns in SCZ and mood disorders are discussed. The review also stresses the value of miRNAs in precision neuropsychiatry, where they could predict treatment outcomes and aid in disease management. Furthermore, the study of conserved miRNAs in model organisms like Drosophila underscores their broad utility and provides deeper mechanistic insights into their biological functions. This comprehensive examination of miRNAs across various conditions advocates for their integration into clinical practice, promising advancements in personalized healthcare for neurological and psychiatric conditions.

Advances in different adult stem cell-derived exosomal non-coding RNAs for the treatment of neurological disorders: a narrative review

Neurological disorders are being increasingly recognized as major causes of death and disability around the world. Neurological disorders refer to a broad range of medical conditions that affect the brain and spinal cord. These disorders can have various causes, including genetic factors, infections, trauma, autoimmune reactions, or neurodegenerative processes. Each disorder has its own unique symptoms, progression, and treatment options. Optimal communication between interneurons and neuron-glia cells within the homeostatic microenvironment is of paramount importance. Within this microenvironment, exosomes play a significant role in promoting intercellular communication by transferring a diverse cargo of contents, including proteins, lipids, and non-coding RNAs (ncRNAs). Partially, nervous system homeostasis is preserved by various stem cell-derived exosomal ncRNAs, which include circular RNAs (circRNAs), long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and PIWI-interacting RNAs (piRNAs). The diversity of these exosomal ncRNAs suggests their potential to influence multiple pathways and cellular processes within the nervous system. Stem cell-derived exosomes and their ncRNA contents have been investigated for potential therapeutic uses in neurological disorders, owing to their demonstrated capabilities in neuroprotection, neuroregeneration, and modulation of disease-related pathways. The ability of stem cell-derived exosomes to cross the blood-brain barrier makes them a promising delivery vehicle for therapeutic ncRNAs. This review aims to summarize the current understanding of different stem cell-derived exosomal ncRNAs and their therapeutic potential and clinical applications.

Role of bone marrow mesenchymal stem cell-derived exosomes in reducing neurotoxicity and depression-like behaviors induced by doxorubicin in rats

Background

Doxorubicin (DOX) is a broad-spectrum antitumor drug while its use is limited nowadays due to its neurobiological side effects associated with depression. Bone marrow mesenchymal stem cells (BM-MSCs) derived exosomes are a promising regenerative therapy. In this study, we investigated the therapeutic potentiality of BM-MSCs derived exosomes against the neurotoxicity induced by DOX.

Methods

Twenty-four male albino rats were divided equally in to three groups as follow: group 1 (control), group 2 (rats injected intraperitoneally (i.p|) with DOX at a dose 2.5mg/Kg), and group 3 (rats injected with DOX and BM-MSCs derived exosomes i.p at a dose 1.5ml/Kg). During the experiment the behavior tests were noted, after three weeks rats were sacrificed, serum and brain samples were collected for biochemical, molecular and histopathological examinations.

Results

The results revealed that DOX causing impairment of the locomotor and increasing the anxiety like behavior of rats, marked neuropathological changes, significant elevation of MDA content and TNF-α concentration, reduction of phospholipase (PLD) and acetylcholinesterase (AChE) protein concentration in addition, there were up regulation of JNK, NF-κB and p38 genes and down regulation of Erk1.

Conclusion

Exosomal therapy improved the substantial neurotoxicity of DOX through modulating the markers involved in the neurotoxic signalling pathway of DOX that resulting in improving the pathological lesions and the animal behaviours.

miRNA-Mediated Mechanisms in the Generation of Effective and Safe Oncolytic Viruses

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression by inhibiting the translation of target transcripts. The expression profiles of miRNAs vary in different tissues and change with the development of diseases, including cancer. This feature has begun to be used for the modification of oncolytic viruses (OVs) in order to increase their selectivity and efficacy. OVs represent a relatively new class of anticancer drugs; they are designed to replicate in cancer tumors and destroy them. These can be natural viruses that can replicate within cancer tumor cells, or recombinant viruses created in laboratories. There are some concerns regarding OVs' toxicity, due to their ability to partially replicate in healthy tissues. In addition, lytic and immunological responses upon OV therapy are not always sufficient, so various OV editing methods are used. This review discusses the latest results of preclinical and clinical studies of OVs, modifications of which are associated with the miRNA-mediated mechanism of gene silencing.

Dual-specificity protein phosphatase 6 (DUSP6) overexpression reduces amyloid load and improves memory deficits in male 5xFAD mice

Introduction

Dual specificity protein phosphatase 6 (DUSP6) was recently identified as a key hub gene in a causal VGF gene network that regulates late-onset Alzheimer's disease (AD). Importantly, decreased DUSP6 levels are correlated with an increased clinical dementia rating (CDR) in human subjects, and DUSP6 levels are additionally decreased in the 5xFAD amyloidopathy mouse model.

Methods

To investigate the role of DUSP6 in AD, we stereotactically injected AAV5-DUSP6 or AAV5-GFP (control) into the dorsal hippocampus (dHc) of both female and male 5xFAD or wild type mice, to induce overexpression of DUSP6 or GFP.

Results

Barnes maze testing indicated that DUSP6 overexpression in the dHc of 5xFAD mice improved memory deficits and was associated with reduced amyloid plaque load, Aß1-40 and Aß1-42 levels, and amyloid precursor protein processing enzyme BACE1, in male but not in female mice. Microglial activation, which was increased in 5xFAD mice, was significantly reduced by dHc DUSP6 overexpression in both males and females, as was the number of "microglial clusters," which correlated with reduced amyloid plaque size. Transcriptomic profiling of female 5xFAD hippocampus revealed upregulation of inflammatory and extracellular signal-regulated kinase pathways, while dHc DUSP6 overexpression in female 5xFAD mice downregulated a subset of genes in these pathways. Gene ontology analysis of DEGs (p < 0.05) identified a greater number of synaptic pathways that were regulated by DUSP6 overexpression in male compared to female 5xFAD.

Discussion

In summary, DUSP6 overexpression in dHc reduced amyloid deposition and memory deficits in male but not female 5xFAD mice, whereas reduced neuroinflammation and microglial activation were observed in both males and females, suggesting that DUSP6-induced reduction of microglial activation did not contribute to sex-dependent improvement in memory deficits. The sex-dependent regulation of synaptic pathways by DUSP6 overexpression, however, correlated with the improvement of spatial memory deficits in male but not female 5xFAD.

MicroRNA biomarkers as next-generation diagnostic tools for neurodegenerative diseases: a comprehensive review

Neurodegenerative diseases (NDs) are characterized by abnormalities within neurons of the brain or spinal cord that gradually lose function, eventually leading to cell death. Upon examination of affected tissue, pathological changes reveal a loss of synapses, misfolded proteins, and activation of immune cells-all indicative of disease progression-before severe clinical symptoms become apparent. Early detection of NDs is crucial for potentially administering targeted medications that may delay disease advancement. Given their complex pathophysiological features and diverse clinical symptoms, there is a pressing need for sensitive and effective diagnostic methods for NDs. Biomarkers such as microRNAs (miRNAs) have been identified as potential tools for detecting these diseases. We explore the pivotal role of miRNAs in the context of NDs, focusing on Alzheimer's disease, Parkinson's disease, Multiple sclerosis, Huntington's disease, and Amyotrophic Lateral Sclerosis. The review delves into the intricate relationship between aging and NDs, highlighting structural and functional alterations in the aging brain and their implications for disease development. It elucidates how miRNAs and RNA-binding proteins are implicated in the pathogenesis of NDs and underscores the importance of investigating their expression and function in aging. Significantly, miRNAs exert substantial influence on post-translational modifications (PTMs), impacting not just the nervous system but a wide array of tissues and cell types as well. Specific miRNAs have been found to target proteins involved in ubiquitination or de-ubiquitination processes, which play a significant role in regulating protein function and stability. We discuss the link between miRNA, PTM, and NDs. Additionally, the review discusses the significance of miRNAs as biomarkers for early disease detection, offering insights into diagnostic strategies.

Extracellular vesicles as nanotheranostic platforms for targeted neurological disorder interventions

Central Nervous System (CNS) disorders represent a profound public health challenge that affects millions of people around the world. Diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and traumatic brain injury (TBI) exemplify the complexities and diversities that complicate their early detection and the development of effective treatments. Amid these challenges, the emergence of nanotechnology and extracellular vesicles (EVs) signals a new dawn for treating and diagnosing CNS ailments. EVs are cellularly derived lipid bilayer nanosized particles that are pivotal in intercellular communication within the CNS and have the potential to revolutionize targeted therapeutic delivery and the identification of novel biomarkers. Integrating EVs with nanotechnology amplifies their diagnostic and therapeutic capabilities, opening new avenues for managing CNS diseases. This review focuses on examining the fascinating interplay between EVs and nanotechnology in CNS theranostics. Through highlighting the remarkable advancements and unique methodologies, we aim to offer valuable perspectives on how these approaches can bring about a revolutionary change in disease management. The objective is to harness the distinctive attributes of EVs and nanotechnology to forge personalized, efficient interventions for CNS disorders, thereby providing a beacon of hope for affected individuals. In short, the confluence of EVs and nanotechnology heralds a promising frontier for targeted and impactful treatments against CNS diseases, which continue to pose significant public health challenges. By focusing on personalized and powerful diagnostic and therapeutic methods, we might improve the quality of patients.

MicroRNAs dysregulated in multiple sclerosis affect the differentiation of CG-4 cells, an oligodendrocyte progenitor cell line

Introduction

Demyelination is one of the hallmarks of multiple sclerosis (MS). While remyelination occurs during the disease, it is incomplete from the start and strongly decreases with its progression, mainly due to the harm to oligodendrocyte progenitor cells (OPCs), causing irreversible neurological deficits and contributing to neurodegeneration. Therapeutic strategies promoting remyelination are still very preliminary and lacking within the current treatment panel for MS.

Methods

In a previous study, we identified 21 microRNAs dysregulated mostly in the CSF of relapsing and/or remitting MS patients. In this study we transfected the mimics/inhibitors of several of these microRNAs separately in an OPC cell line, called CG-4. We aimed (1) to phenotypically characterize their effect on OPC differentiation and (2) to identify corroborating potential mRNA targets via immunocytochemistry, RT-qPCR analysis, RNA sequencing, and Gene Ontology enrichment analysis.

Results

We observed that the majority of 13 transfected microRNA mimics decreased the differentiation of CG-4 cells. We demonstrate, by RNA sequencing and independent RT-qPCR analyses, that miR-33-3p, miR-34c-5p, and miR-124-5p arrest OPC differentiation at a late progenitor stage and miR-145-5p at a premyelinating stage as evidenced by the downregulation of premyelinating oligodendrocyte (OL) [Tcf7l2, Cnp (except for miR-145-5p)] and mature OL (Plp1, Mbp, and Mobp) markers, whereas only miR-214-3p promotes OPC differentiation. We further propose a comprehensive exploration of their change in cell fate through Gene Ontology enrichment analysis. We finally confirm by RT-qPCR analyses the downregulation of several predicted mRNA targets for each microRNA that possibly support their effect on OPC differentiation by very distinctive mechanisms, of which some are still unexplored in OPC/OL physiology.

Conclusion

miR-33-3p, miR-34c-5p, and miR-124-5p arrest OPC differentiation at a late progenitor stage and miR-145-5p at a premyelinating stage, whereas miR-214-3p promotes the differentiation of CG-4 cells. We propose several potential mRNA targets and hypothetical mechanisms by which each microRNA exerts its effect. We hereby open new perspectives in the research on OPC differentiation and the pathophysiology of demyelination/remyelination, and possibly even in the search for new remyelinating therapeutic strategies in the scope of MS.

Navigating the brain: the role of exosomal shuttles in precision therapeutics

Brain diseases have become one of the leading roots of mortality and disability worldwide, contributing a significant part of the disease burden on healthcare systems. The blood-brain barrier (BBB) is a primary physical and biological obstacle that allows only small molecules to pass through it. Its selective permeability is a significant challenge in delivering therapeutics into the brain for treating brain dysfunction. It is estimated that only 2% of the new central nervous system (CNS) therapeutic compounds can cross the BBB and achieve their therapeutic targets. Scientists are exploring various approaches to develop effective cargo delivery vehicles to promote better therapeutics targeting the brain with minimal off-target side effects. Despite different synthetic carriers, one of the natural brain cargo delivery systems, "exosomes," are now employed to transport drugs through the BBB. Exosomes are naturally occurring small extracellular vesicles (EVs) with unique advantages as a therapeutic delivery system for treating brain disorders. They have beneficial innate aspects of biocompatibility, higher stability, ability to cross BBB, low cytotoxicity, low immunogenicity, homing potential, targeted delivery, and reducing off-site target effects. In this review, we will discuss the limitations of synthetic carriers and the utilization of naturally occurring exosomes as brain-targeted cargo delivery vehicles and highlight the methods for modifying exosome surfaces and drug loading into exosomes. We will also enlist neurodegenerative disorders targeted with genetically modified exosomes for their treatment.