Unlocking the Therapeutic Potential of Exosomes Derived From Nasal Olfactory Mucosal Mesenchymal Stem Cells: Restoring Synaptic Plasticity, Neurogenesis, and Neuroinflammation in Schizophrenia

Unraveling the potential of neuroinflammation and autophagy in schizophrenia

Schizophrenia (SCZ) is a complex and chronic psychiatric disorder that affects a significant proportion of the global population. Although the precise etiology of SCZ remains uncertain, recent studies have underscored the involvement of neuroinflammation and autophagy in its pathogenesis. Neuroinflammation, characterized by hyperactivated microglia and markedly elevated pro-inflammatory cytokines, has been observed in postmortem brain tissues of SCZ patients and is closely associated with disease severity. Autophagy, a cellular process responsible for eliminating damaged components and maintaining cellular homeostasis, is believed to play a pivotal role in neuronal health and the onset of SCZ. This review explores the roles and underlying mechanisms of neuroinflammation and autophagy in SCZ, with a particular focus on their intricate interplay. Additionally, we provide an overview of potential therapeutic strategies aimed at modulating neuroinflammation and autophagy, including nutritional interventions, anti-inflammatory drugs, antipsychotics, and plant-derived natural compounds. The review also addresses the dual effects of antipsychotics on autophagy. Our objective is to translate these insights into clinical practice, expanding the therapeutic options available to improve the overall health and well-being of individuals with SCZ.

Dysregulation of MiRNAs in schizophrenia in an Egyptian patient population

Schizophrenia (SZ) is a complex neuropsychiatric disorder influenced by genetic, environmental, and epigenetic factors, including miRNA dysregulation. This study explored the diagnostic and therapeutic potential of miRNAs in SZ, focusing on seven key miRNAs: miR-137-3p, miR-34a-5p, miR-432-5p, miR-130b-3p, miR-346, miR-195-5p, and miR-103a-3p. Results revealed significant dysregulation of miR-137-3p, miR-195-5p, miR-346, and miR-103a-3p, highlighting their relevance to SZ pathology. Upregulation of miR-137-3p correlated with enhanced cognitive performance, as evidenced by improved scores on the Wisconsin Card Sorting Test (WCST) and Trail Making Test B (TMT-B). Conversely, miR-195-5p and miR-346 were strongly associated with cognitive processing speed, while miR-103a-3p downregulation was linked to reduced conceptual flexibility. Cluster analyses demonstrated that miRNA expression levels varied significantly based on antipsychotic treatment and receptor targeting, suggesting potential regulatory effects of medication. Importantly, miRNAs were measured in PBMCs, highlighting their feasibility as non-invasive biomarkers. The study underscores the diagnostic value of miRNAs, offering a promising avenue for early detection and personalized interventions in SZ. Future research should validate these findings across diverse cohorts and investigate miRNA-based therapeutic strategies. By integrating miRNA profiling into clinical practice, this study provides a foundation for advancing precision medicine in SZ management.

The roles of extracellular vesicles in mental disorders: information carriers, biomarkers, therapeutic agents

Mental disorders are complex conditions that encompass various symptoms and types, affecting approximately 1 in 8 people globally. They place a significant burden on both families and society as a whole. So far, the etiology of mental disorders remains poorly understood, making diagnosis and treatment particularly challenging. Extracellular vesicles (EVs) are nanoscale particles produced by cells and released into the extracellular space. They contain bioactive molecules including nucleotides, proteins, lipids, and metabolites, which can mediate intercellular communication and are involved in various physiological and pathological processes. Recent studies have shown that EVs are closely linked to mental disorders like schizophrenia, major depressive disorder, and bipolar disorder, playing a key role in their development, diagnosis, prognosis, and treatment. Therefore, based on recent research findings, this paper aims to describe the roles of EVs in mental disorders and summarize their potential applications in diagnosis and treatment, providing new ideas for the future clinical transformation and application of EVs.

Extracellular vesicles as precision therapeutics for psychiatric conditions: targeting interactions among neuronal, glial, and immune networks

The critical role of the immune system in brain function and dysfunction is well recognized, yet development of immune therapies for psychiatric diseases has been slow due to concerns about iatrogenic immune deficiencies. These concerns are emphasized by the lack of objective diagnostic tools in psychiatry. A promise to resolve this conundrum lies in the exploitation of extracellular vesicles (EVs) that are physiologically produced or can be synthetized. EVs regulate recipient cell functions and offer potential for EVs-based therapies. Intranasal EVs administration enables the targeting of specific brain regions and functions, thereby facilitating the design of precise treatments for psychiatric diseases. The development of such therapies requires navigating four dynamically interacting networks: neuronal, glial, immune, and EVs. These networks are profoundly influenced by brain fluid distribution. They are crucial for homeostasis, cellular functions, and intercellular communication. Fluid abnormalities, like edema or altered cerebrospinal fluid (CSF) dynamics, disrupt these networks, thereby negatively impacting brain health. A deeper understanding of the above-mentioned four dynamically interacting networks is vital for creating diagnostic biomarker panels to identify distinct patient subsets with similar neuro-behavioral symptoms. Testing the functional pathways of these biomarkers could lead to new therapeutic tools. Regulatory approval will depend on robust preclinical data reflecting progress in these interdisciplinary areas, which could pave the way for the design of innovative and precise treatments. Highly collaborative interdisciplinary teams will be needed to achieve these ambitious goals.

Extracellular vesicles derived from mesenchymal stem cells alleviate depressive-like behavior in a rat model of chronic stress

Depression is a prevalent chronic psychiatric disorder with a growing impact on global health. Current treatments often fail to achieve full remission, highlighting the need for alternative therapeutic strategies. Mesenchymal stem cells (MSCs) have attracted significant interest for their therapeutic potential in neuropsychiatric disorders, primarily due to their capacity to target neuroinflammation. This study aimed to investigate if extracellular vesicles derived from human umbilical MSCs (hucMSCs) promote behavioral beneficial actions in a rat model of chronic unpredictable mild stress (CUMS). We show that a single dose of hucMSCs or their derived EVs (hucMSC-EVs) via the tail vein alleviated depressive-like behavior in rats, reduced markers of neuroinflammation, reduced pro-inflammatory cytokines (IL-1β and TNF-α), and increased the number and dendritic complexity of DCX-positive cells in the dentate gyrus. Proteomic analysis of EVs revealed the presence of proteins involved in modulation of inflammatory processes and cell activation. Our study demonstrates EVs derived from hucMSCs can effectively mitigate depressive symptoms by modulating neuroinflammatory pathways and enhancing neurogenesis. These findings support further exploration of MSC-derived EVs as a novel therapeutic option for neuropsychiatric disorders.

Olfactory mucosa mesenchymal stem cell-derived exosomes protect against neuroinflammation after subarachnoid hemorrhage by activating mitophagy

Subarachnoid hemorrhage (SAH) can lead to significant acute neuroinflammation, with treatment outcomes often being inadequate. Olfactory mucosa mesenchymal stem cells (OM-MSCs) have promising therapeutic potential in nerve regeneration and functional recovery. This investigation sought to elucidate the functional mechanisms through which exosomes derived from OM-MSCs provide protection against neuroinflammation following SAH. Mouse OM-MSCs and their exosomes were isolated and characterized using various techniques, including transmission electron microscopy, immunofluorescence staining, Western blotting, flow cytometry, and nanoparticle tracking analysis. Hemin-induced HT22 cells were subsequently utilized to assess the impact of OM-MSC-derived exosomes on the inflammatory response, apoptosis, and mitophagy through ELISAs, Western blotting, qPCR, flow cytometry, and immunofluorescence staining. The impacts of exosomes on neuroinflammation and neuronal damage in SAH model mice were assessed using qPCR, ELISAs, Western blotting, immunofluorescence staining, and TUNEL staining. Exosomes derived from OM-MSCs had the capacity to reduce the levels of proinflammatory factors (IL-6, IL-1β, and TNF-α) and promote apoptosis in hemin-induced HT22 cells. Exosomes alleviated neuroinflammation and neuronal injury post-SAH, as evidenced by the increase in modified Garcia scores, reduction in the brain water content, decrease in blood-brain barrier permeability, decreases in inflammatory marker levels, and reduction in apoptosis rates. Notably, the protective effects of exosomes derived from OM-MSCs on neuroinflammation and apoptosis, both in vitro and in vivo, were mediated via the activation of mitophagy. These findings provide a fresh perspective for subsequent clinical research in the domain of prevention and treatment strategies.

Intranasal delivery of engineered extracellular vesicles promotes neurofunctional recovery in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of disability in adults, significantly affecting patients' quality of life. Extracellular vesicles (EVs) derived from human adipose-derived mesenchymal stem cells (hADSCs) have demonstrated therapeutic potential in TBI treatment. However, their limited targeting ability, short half-life, and low bioavailability present significant challenges for clinical application. In this study, we engineered extracellular vesicles (EEVs) by transfecting hADSCs with lentivirus and incorporating ultra-small paramagnetic nanoparticles (USPNs), resulting in EVs with enhanced miRNA expression and targeted delivery capabilities. These EEVs were administered intranasally to specifically target injury sites, effectively modulating the NF-κB signaling pathway to suppress neuroinflammation. In both in vitro and in vivo assessments, EEVs exhibited superior efficacy in promoting neurofunctional recovery and neurogenesis after brain injury compared to unmodified EVs. Furthermore, validation using human brain organoid models confirmed EEVs' remarkable ability to suppress neuroinflammation, offering a promising strategy for TBI treatment.

Stem cell therapy for the treatment of psychiatric disorders: a real hope for the next decades

In this review, it is evaluated the progress in the application of stem cell therapy to ameliorate the symptoms of bipolar disorder, major depression, schizophrenia, and autism. These disorders are highly prevalent in clinical medicine and are responsible for high levels of psychosocial disability among patients. All of them share common biomedical features, such as complex and variable genetic substrates, significant susceptibility to environmental changes, and insufficient knowledge of their pathogenesis. In addition, the responsiveness of patients to pharmacological treatment is heterogeneous, and in some cases, no treatment is available. Therefore, the development of stem cell-based regenerative medicine and its possible combination with emerging therapeutic approaches that promote neural plasticity are expected to advance neuropsychiatry in the next few decades.

Advances in 3D printing combined with tissue engineering for nerve regeneration and repair

The repair of nerve damage has long posed a challenge owing to limited self-repair capacity and the highly differentiated nature of nerves. While new therapeutic and pharmacologic interventions have emerged in neurology, their regenerative efficacy remains limited. Tissue engineering offers a promising avenue for overcoming the limitations of conventional treatments and increasing the outcomes of regenerative repair. By implanting scaffolds into damaged nerve tissue sites, the repair and functional reconstruction of nerve injuries can be significantly facilitated. The integration of three-dimensional (3D) printing technology introduces a novel approach for accurate simulation and scalably fabricating neural tissue structures. Tissue-engineered scaffolds developed through 3D printing technology are expected to be a viable therapeutic option for nerve injuries, with broad applicability and continued development. This review systematically examines recent advances in 3D printing and tissue engineering for nerve regeneration and repair. It details the basic principles and construction strategies of neural tissue engineering and explores the crucial role of 3D printing technology. Additionally, it elucidates specific applications and technical challenges associated with this integrated approach, thereby providing valuable insights into innovative strategies and pragmatic implementation within this field.

Deciphering and Targeting the ESR2-miR-10a-5p-BDNF Axis in the Prefrontal Cortex: Advancing Postpartum Depression Understanding and Therapeutics

Postpartum depression (PPD) represents a important emotional disorder emerging after childbirth, characterized by its complex etiology and challenging management. Despite extensive preclinical and clinical investigations underscoring the role of estrogen fluctuations and estrogen receptor genes in PPD, the precise mechanisms underpinning this condition have remained elusive. In our present study, animal behavioral studies have elucidated a tight link between the aberrant expression of ESR2, miR-10a-5p, and BDNF in the prefrontal cortex of mice exhibiting postpartum depressive-like behavior, shedding light on the potential molecular pathways involved. Integrating bioinformatics, in vivo, and cell transfection methodologies has unraveled the intricate molecular interplay between ESR2, miR-10a-5p, and BDNF. We identified ESR2 as a negative transcription factor that down-regulates miR-10a transcription, while miR-10a-5p serves as a negative regulator that suppresses BDNF expression. This molecular triad contributes to the pathogenesis of PPD by affecting synaptic plasticity, as evidenced by alterations in synapse-related proteins (e.g., SYP, SYN, and PSD95) and glutamate receptor expression. Additionally, primary neuron culture studies have confirmed the critical roles of ESR2 and miR-10a-5p in maintaining neuronal growth and morphology. Therapeutic interventions, including stereotactic and intranasal administration of antagomir or BDNF, have demonstrated significant potential in treating PPD, highlighting the therapeutic implications of targeting the negative transcriptional and regulatory interactions between ESR2, miR-10a-5p, and BDNF. Our findings endorse the hypothesis that estrogen fluctuations and estrogen receptor gene activity are pivotal stressors and risk factors for PPD, affecting central nervous system functionality and precipitating depressive behaviors postpartum.

The efficacy of Lactobacillus and Bifidobacterium in patients with schizophrenia: a meta-analysis

The modulation of gut microbiota through probiotics holds promise as a novel avenue for schizophrenia treatment. This study aims to analyze probiotic complementary therapy on individuals with schizophrenia systematically, to investigate probiotic efficacy, potential mechanisms, and implications for clinical practice. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched in Medline, Web of Science, Embase, ClinicalTrials.gov, CNKI, VIP, and WanFang databases using keywords ("probiotics" OR "prebiotics" OR "synbiotics" OR "Lactobacillus" OR "Bifidobacterium") AND ("schizophrenia"), focused on randomized controlled trials published before July 1, 2023. Among the identified studies, 8 randomized controlled trials met the inclusion criteria, encompassing a total of 342 participants in the intervention group and 306 participants in the control group. Our analysis revealed a statistically significant reduction (p = 0.03) in the total Positive and Negative Syndrome Scale (PANSS) scores following probiotic treatment in individuals with schizophrenia. While no statistical significance was observed in individual subscales (P > 0.05), significant improvements were noted in insulin levels, Insulin Resistance Index (IRI), and glucose levels. Additionally, the Quantitative Insulin Sensitivity Check Index (QUICKI) demonstrated a significant increase (all P < 0.05). The probiotic intervention significantly reduced gastrointestinal discomfort among schizophrenia patients (P = 0.003). This study suggests that probiotics could hold therapeutic potential for addressing clinical symptoms, abnormal glucose metabolism, and gastrointestinal discomfort in individuals with schizophrenia. Future research should encompass comparative trials employing robust experimental designs to explore the differential effects of various probiotic strains on schizophrenia treatment to provide evidence-based therapeutic approaches. TRIAL REGISTRATION: This review protocol was pre-registered on PROSPERO (No. CRD42023455273).

Emerging role and translational potential of small extracellular vesicles in neuroscience

Small extracellular vesicles (sEV) are endogenous lipid-bound membrane vesicles secreted by both prokaryotic and eukaryotic cells into the extracellular environment, performs several biological functions such as cell-cell communication, transfer of proteins, mRNA, and ncRNA to target cells in distant sites. Due to their role in molecular pathogenesis and its potential to deliver biological cargo to target cells, it has become a prominent area of interest in recent research in the field of Neuroscience. However, their role in neurological disorders, like neurodegenerative diseases is more complex and still unaddressed. Thus, this review focuses on the role of sEV in neurodegenerative and neurodevelopmental diseases, including their biogenesis, classification, and pathogenesis, with translational advantages and limitations in the area of neurobiology.

Plasma miRNAs as potential biomarkers for schizophrenia in a Jordanian cohort

Background

Schizophrenia (SZ), a complex and chronic neuropsychiatric disorder affecting approximately 1 % of the general population, presents diagnostic challenges due to the absence of reliable biomarkers, and relying mainly on clinical observations. MicroRNAs (miRNAs) signatures in a wide range of diseases, including psychiatric disorders, hold immense potential for serving as biomarkers. This study aimed to analyze the expression levels of specific microRNAs (miRNAs) namely miR-29b-3p, miR-106b-5p, and miR-199a-3p and explore their diagnostic potential for SZ in Jordanian patients.

Methods

Small RNAs (miRNAs) were extracted from plasma samples of 30 SZ patients and 35 healthy controls. RNA was reverse transcribed and quantified by real-time polymerase chain reaction (qRT-PCR). The expression levels of three miRNAs (miR-29b-3p, miR-106b-5p and miR-199a-3p) were analyzed. Receiver operating characteristic (ROC) curves analysis was performed to evaluate diagnostic value of these miRNAs. Target genes prediction, functional enrichment and pathway analyses were done using miRWalk and Metascape. STRING database was used to construct protein-protein network and identify hub genes.

Results

Notably, miR-106b-5p and miR-199a-3p were significantly upregulated (p < 0.0001), while miRNA-29b-3p was downregulated (p < 0.0001) in SZ patients compared to controls. The diagnostic potential was assessed through ROC curves, revealing substantial diagnostic value for miR-199a-3p (AUC: 0.979) followed by miR-106b-5p (AUC: 0.774), with limited diagnostic efficacy for miR-29b-3p. Additionally, bioinformatic analyses for the predicted target genes of the diagnostically significant miRNAs uncovered Gene Ontology (GO) terms related to neurological development, including morphogenesis, which is involved in neuron differentiation, brain development, head development, and neuron projection morphogenesis. These findings highlight a potential connection between the identified miRNAs and SZ pathophysiology in the studied Jordanian population. Furthermore, a protein-protein interaction network from the target genes identified in association with neurological development in the Gene Ontology (GO) terms deepens our comprehension of the molecular landscape of the regulated target genes.

Conclusions

This comprehensive exploration highlights the promising role of miRNAs in unraveling intricate molecular pathways associated with SZ in the Jordanian cohort and suggests that plasma miRNAs could serve as reliable biomarkers for SZ diagnosis and disease progression. Remarkably, this study represents the first investigation into the role of circulating miRNA expression among Jordanian patients with SZ, providing valuable insights into the diagnostic landscape of this disorder.