Extracellular vesicles through the blood-brain barrier: a review

A novel function for exosomes in depression

Exosomes are a class of extracellular vesicles that encompass a diverse array of bioactive molecules, including proteins, lipids, mRNA, and microRNA(miRNA). Virtually all cell types release exosomes under both physiological and pathological conditions. In addition to electrical and chemical signals, exosomes are an alternative route of signaling between cells in the brain. In the brain, they are involved in processes such as synaptic plasticity, neuronal stress response, intercellular communication, and neurogenesis. A number of studies have shown that exosomes regulate the occurrence and development of depression by participating in the regulation of hypothalamic-pituitary-adrenal axis, brain-derived neurotrophic factor, immune inflammatory response and other mechanisms, showing that they may become potential biological agents for the diagnosis and treatment of depression. In addition, exosomes have the ability to easily cross the blood-brain barrier, making them ideal drug or molecular delivery tools for the central nervous system. Engineered exosomes have good brain targeting ability, and their research in central nervous system diseases has begun to emerge. However, the molecular pathways involved in the pathogenesis of depression remain unknown, and further studies are needed to fully understand the role of exosomes in the development or improvement of depression. Therefore, in this review, we mainly focus on the diagnostic performance and therapeutic effect of exosomes in depression, and explore the advantages of exosomes as biomarkers and gene delivery vectors for depression.

Nanoparticles targeting the central circadian clock: Potential applications for neurological disorders

Circadian rhythms and their involvement with various human diseases, including neurological disorders, have become an intense area of research for the development of new pharmacological treatments. The location of the circadian clock machinery in the central nervous system makes it challenging to reach molecular targets at therapeutic concentrations. In addition, a timely administration of the therapeutic agents is necessary to efficiently modulate the circadian clock. Thus, the use of nanoparticles in circadian clock dysfunctions may accelerate their clinical translation by addressing these two key challenges: enhancing brain penetration and/or enabling their formulation in chronodelivery systems. This review describes the implications of the circadian clock in neurological pathologies, reviews potential molecular targets and their modulators and suggests how the use of nanoparticle-based formulations could improve their clinical success. Finally, the potential integration of nanoparticles into chronopharmaceutical drug delivery systems will be described.

The biological and technical challenges facing utilizing circulating tumor DNA in non-metastatic breast cancer patients

Breast cancer is one of the most prevalent cancers and has emerged as a major global challenge. Circulating tumor DNA (ctDNA), a liquid biopsy method, overcomes the accessibility limitations of tissue-based testing and is widely used for monitoring minimal residual disease and molecular relapse, predicting prognosis, evaluating the response of neoadjuvant therapy, and optimizing treatment decisions in non-metastatic breast cancer. However, the application of ctDNA still faces many challenges. Here, we survey the clinical applications of ctDNA in non-metastatic breast cancer and discuss the significant biological and technical challenges of utilizing ctDNA. Importantly, we investigate potential avenues for addressing the challenges. In addition, emerging technologies, including fragmentomics detection, methylation sequencing, and long-read sequencing, have clinical potential and could be a future direction. Proper utilization of machine learning facilitates the identification of meaningful patterns from complex fragment and methylation profiles of ctDNA. There is still a lack of clinical trials focused on the subsets of ctDNA (e.g., circulating mitochondrial DNA), ctDNA-inferred drug-resistant clonal evolution, tumor heterogeneity, and ctDNA-guided clinical decision-making in non-metastatic breast cancer. Due to regional differences in the number of registered clinical trials, it is essential to enhance communication and foster global collaboration to advance the field.

Noninvasive Assessment of β-Secretase Activity Through Click Chemistry-Mediated Enrichment of Neuronal Extracellular Vesicles to Detect Alzheimer's Disease

Alzheimer's disease (AD), the most prevalent type of dementia, is characterized by a biological process that begins with the development of AD neuropathologic change (ADNPC) while individuals remain asymptomatic. A key molecular hallmark of ADNPC is the accumulation of amyloid-β plaques. β-secretase plays a critical role in the upstream pathological cleavage of amyloid precursor protein (APP), producing amyloid-β peptides that are prone to misfolding, ultimately contributing to plaque formation. Neuronal extracellular vesicles (NEVs) in the blood transport β-secretase and preserve its activity, allowing for noninvasive profiling of β-secretase activity for detecting early onset of ADNPC. In this study, a novel approach is approached for noninvasive assessment of β-secretase activity in AD patients using an NEV β-secretase activity assay. This assay identifies NEVs exhibiting colocalization of NEV markers with AD-associated β-secretase, generating a β-secretase activity profile for each patient. The NEV β-secretase activity assay represents a significant advancement in leveraging the diagnostic potential of NEVs, offering a noninvasive, quantitative method for reliably assessing β-secretase activity to detect the early onset of ADNPC.

Erythrocyte-derived extracellular vesicles transcytose across the blood-brain barrier to induce Parkinson's disease-like neurodegeneration

Parkinson's disease (PD) is a neurodegenerative illness characterized by motor and non-motor features. Hallmarks of the disease include an extensive loss of dopaminergic neurons in the substantia nigra pars compacta, evidence of neuroinflammation, and the accumulation of misfolded proteins leading to the formation of Lewy bodies. While PD etiology is complex and identifying a single disease trigger has been a challenge, accumulating evidence indicates that non-neuronal and peripheral factors may likely contribute to disease onset and progression. The brain is shielded from peripheral factors by the blood-brain barrier (BBB), which tightly controls the entry of systemic molecules and cells from the blood to the brain. The BBB integrates molecular signals originating from the luminal (blood) and abluminal (brain) sides of the endothelial wall, regulating these exchanges. Of particular interest are erythrocytes, which are not only the most abundant cell type in the blood, but they also secrete extracellular vesicles (EVs) that display disease-specific signatures over the course of PD. Erythrocyte-derived EVs (EEVs) could provide a route by which pathological molecular signals travel from the periphery to the central nervous system. The primary objective of this study was to evaluate, in a human-based platform, mechanisms of EEV transport from the blood to the brain under physiological conditions. The secondary objective was to determine the ability of EEVs, generated by erythrocytes of healthy donors or patients, to induce PD-like features. We leveraged two in vitro models of the BBB, the transwell chambers and a microfluidic BBB chip generated using human induced pluripotent stem cells. Our findings suggest that EEVs transcytose from the vascular to the brain compartment of the human BBB model via a caveolin-dependant mechanism. Furthermore, EEVs derived from individuals with PD altered BBB integrity compared to healthy EEV controls, and clinical severity aggravated the loss of barrier integrity and increased EEV extravasation into the brain compartment. PD-derived EEVs reduced ZO-1 and Claudin 5 tight junction levels in BMEC-like cells and induced the selective atrophy of dopaminergic neurons. In contrast, non-dopaminergic neurons were not affected by treatment with PD EEVs. In summary, our data suggest that EEV interactions at the human BBB can be studied using a highly translational human-based brain chip model, and EEV toxicity at the neurovascular unit is exacerbated by disease severity.

Review: The potential role of placental extracellular vesicles in blood-brain barrier disruption and neuroinflammation in preeclampsia

Preeclampsia is a complex pregnancy disorder characterized by hypertension and multisystem organ damage, notably affecting the liver, kidneys, and brain. Eclampsia, a severe form of preeclampsia, is marked by the sudden onset of generalized tonic-clonic seizures. Brain complications, including eclampsia, are responsible for 60-70 % of preeclampsia-related maternal deaths, particularly in low-income regions. Despite the significant impact of brain complications in preeclampsia, their underlying pathophysiology remains unclear. Evidence suggests that brain edema in preeclampsia and eclampsia results from disruption of the blood-brain barrier (BBB). Although direct analysis of the BBB is challenging, in vitro studies indicate that plasma from women with preeclampsia can compromise the BBB, with the specific circulating factors involved still unidentified. Among the potential culprits, recent findings highlight placental-derived small extracellular vesicles (PDsEVs) as key players in BBB disruption observed in preeclampsia. This review examines the role of PDsEVs in the pathophysiology of brain edema associated with preeclampsia, emphasizing areas for future research, including neuroinflammation and neuron dysfunction. Additionally, we discuss the protective role of magnesium sulfate in these processes.

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.

The microvascular endothelium of the blood-brain barrier is highly restrictive to JC Polyomavirus neuroinvasion

JC Polyomavirus is the causative agent of progressive multifocal leukoencephalopathy (PML), an often-fatal demyelinating disease. Unfortunately, a diagnosis of PML occurs only after patients have suffered irreversible neuropathologies. The first step in the initiation of PML is viral entry to the brain, but the route and mechanisms responsible for neuroinvasion have not been well established. To gain a better understanding of this, we asked whether purified virus or virus associated with extracellular vesicles (EVs) could penetrate two different cell culture models of the blood-brain barrier. In one model, we used the hCMEC/D3 brain endothelial cell line, and in the other, we used pluripotent stem cells induced to a brain endothelial cell phenotype (iPSC-EC). We found that neither cell type was permissive to viral infection, but the virus bound and was internalized by both in a sialic acid-dependent manner. Despite virus internalization into these cells, very few virions or virus-associated extracellular vesicles (virus-EVs) penetrated the barriers. The small amount of virus or virus-EVs that did pass through either barrier was sufficient to establish infection in human glial cells. Our findings demonstrate that limited amounts of infectious virions and virus-associated EVs can traverse the brain microvascular endothelium and establish infection.IMPORTANCEThe human polyomavirus, JC Polyomavirus (JCPyV), causes a rapidly progressing demyelinating disease in immunocompromised or immunomodulated patients. Demyelinating lesions are often seen surrounding blood vessels in the brain. In this paper, we used two models to recapitulate a minimal blood-brain barrier and found that both were highly restrictive of virus penetration. A small amount of virus succeeded in crossing both barriers and was sufficient to establish infection of human glia. These data have direct implications for mechanisms used by JCPyV to invade the CNS and cause neurological disease.

Extracellular Vesicles Carrying Tenascin-C are Clinical Biomarkers and Improve Tumor-Derived DNA Analysis in Glioblastoma Patients

Extracellular vesicles (EVs) act as carriers of biological information from tumors to the bloodstream, enabling the detection of circulating tumor material and tracking of disease progression. This is particularly crucial in glioblastoma, a highly aggressive and heterogeneous tumor that is challenging to monitor. Using imaging flow cytometry (IFCM), we conducted an immunophenotyping analysis of eight glioma-associated antigens and tetraspanins in plasma EVs from 37 newly diagnosed glioblastoma patients (pre- and post-surgery), 11 matched individuals with recurrent glioblastoma, and 22 healthy donors (HD). Tenascin-C (TNC) positive EVs displayed the strongest differences in newly diagnosed and recurrent glioblastoma patients, when compared to non-tumor subjects. Among dual-positive subpopulations, TNC+/CD9+ EVs were the most elevated in newly diagnosed (FC = 7.6, p <0.0001, AUC = 81%) and recurrent patients (FC = 16.5, p <0.0001; AUC = 90%) than HD. In comparison with other CNS tumors (n = 25), this subpopulation was also 34.5-fold higher in glioblastoma than in meningioma cases (p <0.01). Additionally, TNC+/CD9+ EV levels were 3.3-fold elevated in cerebrospinal fluid from glioblastoma patients (n = 6) than controls (p <0.05). Aberrant TNC levels were further observed in glioblastoma EVs from different sources and purified via different methods. Immunohistochemical analysis revealed high levels of TNC in tumor tissues. Spatial transcriptomic analysis indicated a TNC overexpression in malignant cell populations of glioblastoma resections, particularly in cells with mesenchymal-like signatures and chromosomal aberrations. Lastly, we purified TNC+ EVs from plasma of 21 glioblastoma patients by magnetic sorting and detected the oncogenic mutation TERT*C228T by droplet digital PCR. The mutant allele frequency was higher in TNC+ EVs vs TNC-negative EVs (FC = 32, p <0.001), total EVs (FC = 5.3, p <0.001) or cell-free DNA (FC = 5.3, p <0.01). In conclusion, circulating TNC+ EVs may have potential as clinical biomarkers in glioblastoma, and their purification could improve the identification of tumor-specific mutations in liquid biopsies.

In vivo vectorization and delivery systems for gene therapies and RNA-based therapeutics in oncology

Gene and RNA-based therapeutics represent a promising frontier in oncology, enabling targeted modulation of tumor-associated genes and proteins. This review explores the latest advances in payload vectorization and delivery systems developed for in vivo cancer treatments. We discuss viral and non-viral organic particles, including lipid based nanoparticles and polymeric structures, for the effective transport of plasmids, siRNA, and self-amplifying RNA therapeutics. Their physicochemical properties, strategies to overcome intracellular barriers, and innovations in cell-based carriers and engineered extracellular vesicles are highlighted. Moreover, we consider oncolytic viruses, novel viral capsid modifications, and approaches that refine tumor targeting and immunomodulation. Ongoing clinical trials and regulatory frameworks guide future directions and emphasize the need for safe, scalable production. The potential convergence of these systems with combination therapies paves the way toward personalized cancer medicine.

Extracellular vesicles: new horizons in neurodegeneration

Extracellular vesicles (EVs) are lipid-enclosed nanovesicles secreted by diverse cell types that orchestrate intercellular communication through cargo delivery. Their pivotal roles span from supporting the development of normal central nervous system (CNS) to contributing to the pathogenesis of neurological diseases. Particularly noteworthy is their involvement in the propagation of pathogenic proteins, such as those involved in neurodegenerative disorders, and nucleic acids, closely linking them to disease onset and progression. Moreover, EVs have emerged as promising diagnostic biomarkers for neurological disorders and as tools for disease staging, owing to their ability to traverse the blood-brain barrier and their specific, stable, and accessible properties. This review comprehensively explores the realm of CNS-derived EVs found in peripheral blood, encompassing their detection methods, transport mechanisms, and diverse roles in various neurodegenerative diseases. Furthermore, we evaluate the potentials and limitations of EVs in clinical applications and highlight prospective research directions in this rapidly evolving field.

Isolating Astrocyte-Derived Extracellular Vesicles From Urine

Introduction

Brain-derived extracellular vesicles (BDEVs) can cross the blood-brain barrier and enter the periphery. Therefore, quantifying and analyzing peripherally circulating BDEVs offer a promising approach to directly obtain a window into central nervous system (CNS) pathobiology in vivo. Rapidly evolving CNS diseases require high-frequency sampling, but daily venipuncture of human subjects is highly invasive and usually unfeasible.

Methods

To address this challenge, here we present a novel method for isolating astrocyte-derived extracellular vesicles from urine (uADEVs), combining urine concentration, ultracentrifugation to isolate total EVs, and then glutamate-aspartate transporter (GLAST) EV isolation using an anti-GLAST antibody.

Results

The identity of these GLAST+EVs as uADEVs was confirmed by transmission electron microscopy, nanoparticle tracking analysis, western blotting, and assessment of astrocyte-related neurotrophins.

Conclusions

Leveraging the convenience and availability of urine samples, the non-invasive uADEV approach provides a novel tool that allows high-frequency sampling to investigate rapidly evolving CNS diseases.

Multi-omics analysis of uterine fluid extracellular vesicles reveals a resemblance with endometrial tissue across the menstrual cycle: biological and translational insights

STUDY QUESTION

Does the molecular composition of uterine fluid extracellular vesicles (UF-EVs) reflect endometrial tissue changes across the menstrual cycle?

SUMMARY ANSWER

Concordance between endometrial tissue and UF-EVs exists on miRNA and mRNA levels along the menstrual cycle phases and UF-EV surface proteomic signatures suggest EVs originate from several major endometrial cell populations.

WHAT IS KNOWN ALREADY

The clinical value of endometrial receptivity testing is restricted by invasiveness and the use of only one omics level of input. There is promising evidence that UF-EVs can reflect changes in mid-secretory endometrium, highlighting the potential to establish endometrial receptivity testing right before embryo transfer. However, the dynamic changes of UF-EVs molecular cargo have not been directly compared to endometrial tissue on multiple omics levels.

STUDY DESIGN SIZE DURATION

This cross-sectional study included fertile women from four menstrual cycle phases: proliferative and early-, mid-, and late-secretory phases. In total, 26 paired samples of UF and endometrial tissue were collected. mRNA and miRNA were sequenced, and differential analysis was performed on consecutive phases. UF-EVs were profiled for various protein surface markers associated with different cell types. EVs from epithelial endometrial organoid-conditioned culture media were used as a reference of pure epithelial endometrial EVs.

PARTICIPANTS/MATERIALS SETTING METHODS

Paired UF and endometrial tissue samples were collected from 26 fertile, reproductive-age women. EV isolation from UF was validated using electron microscopy and western blotting, and particle numbers were measured by nanoparticle tracking analysis. The transcriptome and miRNome of UF-EVs and endometrial tissue were sequenced, and differential expression analysis was conducted on consecutive phases of the menstrual cycle. Bead-based EV flow cytometry targeting 37 surface protein markers was used to characterize EVs from UF and endometrial organoids.

MAIN RESULTS AND THE ROLE OF CHANCE

Surface proteome analysis revealed that UF-EVs from the mid-secretory phase had significantly increased expression of natural killer cell marker CD56 (P < 0.005), pan-leukocyte marker CD45 (P < 0.005), pan-T-cell marker CD3 (P < 0.005), and coagulation-related protein CD142 (P < 0.005) compared to those from the proliferative phase, whereas markers associated with endometrial epithelial cells (CD29, CD133, and CD326) did not significantly change across the menstrual cycle. Transcriptomic analysis highlighted differential expression of histone and metallothionein genes that correlated between paired UF-EVs and endometrial tissues in each tested menstrual cycle phase. Principal component analysis of miRNomes of paired UF-EVs and endometrial tissue samples resulted in similar clustering patterns, where mid- and late-secretory samples clustered closely, and proliferative and early-secretory phase samples clustered separately. Half of the differentially expressed miRNAs in each phase in UF-EVs were also differentially expressed in the endometrium. Importantly, nine mid-secretory phase UF-EV DE miRNAs were identified, five of which were common between UF-EVs and endometrial biopsies, including hsa-miR-30d-5p and hsa-miR-200b-3p, both of which were previously implicated in implantation. Notably, three of the nine miRNAs, hsa-miR-200b-3p, hsa-miR-141-3p, and hsa-miR-200a-3p, were predicted to regulate mRNAs in the endometrial tissue and the pre-implantation embryo trophectoderm.

LARGE SCALE DATA

N/A.

LIMITATIONS REASONS FOR CAUTION

The clinical dating of the menstrual cycle phase is based on the first day of menstruation and the time of the LH peak, which does not exclude the possibility that the expected endometrial phase was not reached. The wider limitation of our study is the lack of standardized procedures for collecting UF samples in gynaecological practice, which could challenge the replication of our findings.

WIDER IMPLICATIONS OF THE FINDINGS

Evidence that UF-EVs reflect endometrial phases of menstrual cycle supports the use of UF-EVs in endometrial receptivity testing. Additionally, further studies of UF-EVs in endometrial pathologies could be beneficial for diagnostics, considering that more invasive tissue biopsies only reflect the biopsy site and not the full endometrium.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by the European Regional Development Fund Enterprise Estonia's Applied Research Program under the grant agreement number 2014-2020.4.02.21-0398 (EVREM), the Estonian Research Council (grant nos. PRG1076 and PSG1082), the Horizon Europe NESTOR grant (grant no. 101120075) of the European Commission, the Swedish Research Council (grant no. 2024-02530), the Novo Nordisk Fonden (grant no. NNF24OC0092384), and the National Recovery and Resilience Plan of the Republic of Bulgaria, project number BG-RRP-2.004-0001-C01. A.S.L. received funding from the Becas Fundación Ramón Areces para Estudios Postdoctorales. All the authors declare no conflict of interest.

Platelet-derived extracellular vesicle drug delivery system loaded with kaempferol for treating corneal neovascularization

Platelet-derived extracellular vesicles (PEVs) have drawn attention due to their multifunctionality, ease of procurement, and abundant supply from clinical-grade platelet concentrates. PEVs can be readily endocytosed due to their lipid bilayer membrane and nanoscale structure, enhancing the bioavailability and efficacy of their therapeutic effects. PEVs also contain various trophic factors that enhance their effectiveness as therapeutic agents. Given that nanomedicine provides benefits over traditional treatments for eye diseases by surpassing physical ocular barriers, PEVs combined with the anti-angiogenic agent, kaempferol (KM), were assessed for their capacity to inhibit abnormal blood vessel formation in the cornea. Characterization of the nanoparticles suggested the successful preparation of KM-loaded PEVs (PEV-KM) with a mean diameter of approximately 160 nm and an encapsulation efficiency of around 61 %. PEV-KM was effectively internalized into human vascular endothelial cells, resulting in inhibited function, as evidenced by lower wound closure rates, decreased tube formation capacity, and downregulation of angiogenesis-related gene expression. Moreover, prolonged ocular retention was observed following the topical application of PEV and PEV-KM in mouse eyes. In an alkali-burned corneal neovascularization (CoNV) mouse model, PEV (1 %) was found to decrease vessel formation in the injured cornea. However, the combination of PEV and KM (1 % PEV with KM 6 μg/mL) showed an even stronger effect in inhibiting CoNV and decreasing the expression of proangiogenic and inflammatory cytokines. Overall, our data suggests that the topical administration of PEVs, either alone or alongside KM (PEV-KM), is a promising therapy for the management of CoNV.

Intra and inter-organ communication through extracellular vesicles in obesity: functional role of obesesomes and steatosomes

BACKGROUND

Extracellular vesicles (EVs) represent a sophisticated mechanism of intercellular communication that is implicated in health and disease. Specifically, the role of EVs in metabolic regulation and their implications in metabolic pathologies, such as obesity and its comorbidities, remain unclear.

METHODS

Extracellular vesicles (EVs) were isolated through serial ultracentrifugation from murine adipocytes treated with palmitate or oleic acid, whole visceral and subcutaneous adipose tissue (obesesomes) of bariatric surgery obese donors, and human hepatocytes under steatosis (steatosomes) for functional in vitro experiments. Functional effects on inflammation and glucose and lipid metabolism of target cells (human and murine macrophages and hepatocytes) were assessed using ELISA, RT-PCR, and immunodetection. Isolated EVs from human steatotic (steatosomes) and control hepatocytes (hepatosomes) were characterized for quantity, size, and tetraspanin profile by NTA and Single Particle Interferometric Reflectance Imaging Sensor (SP-IRIS), and their protein cargo analyzed by qualitative (DDA) and quantitative (DIA-SWATH) proteomics using LC-MS/MS. Proteins identified by proteomics were validated by capturing EVs on functionalized chips by SP-IRIS.

RESULTS AND CONCLUSIONS

In this study, we investigated the role of EVs in the local communication between obese adipocytes and immune cells within adipose tissue, and the interaction of steatotic and healthy hepatocytes in the context of fatty liver disease progression. Furthermore, we analyzed obese adipose tissue-to-liver interactions through EV-obesesomes to elucidate their role in obesity-associated hepatic metabolic dysregulation. Our findings reveal that obesesomes promote inflammation and the secretion of pro-inflammatory cytokines upon interaction with macrophages, exerting a significant impact on reducing insulin resistance and altering lipid and glucose metabolism upon interaction with hepatocytes; in both cases, EVs from palmitate-loaded adipocytes and obesesomes from human visceral adipose depots demonstrated the most deleterious effect. Additionally, EVs secreted by steatotic hepatocytes (steatosomes) induced insulin resistance and altered lipid and glucose metabolism in healthy hepatocytes, suggesting their involvement in MASLD development. Proteomic analysis of steatosomes revealed that these vesicles contain liver disease-associated proteins, rendering them significant repositories of real-time biomarkers for the early stages and progression of MASLD.

Engineered Extracellular Vesicles Modified by Angiopep-2 Peptide Promote Targeted Repair of Spinal Cord Injury and Brain Inflammation

Engineered extracellular vesicles play an increasingly important role in the treatment of spinal cord injury. In order to prepare more effective engineered extracellular vesicles, we biologically modified M2 microglia. Angiopep-2 (Ang2) is an oligopeptide that can target the blood-brain barrier. Through single-cell sequencing and immunofluorescence experiments, we confirmed that the expression of LRP-1, the targeted receptor of Ang2, was elevated after spinal cord injury. Subsequently, we integrated the Ang2 peptide segment into M2 microglia to obtain Ang2-EVs, which could successfully target the site of spinal cord injury. However, in order to improve the function of Ang2-EVs, we pretreated M2 microglia with melatonin, which has anti-inflammatory effects, to obtain M-Ang2-EVs. The results of single-nucleus sequencing of the mouse spinal cord verified that neurons and OPCs gradually transformed into subtypes related to nerve repair functions after treatment with M-Ang2-EVs. This is consistent with the sequencing and enrichment analysis of miRNAs contained in M-Ang2-EVs. We further verified through experiments that M-Ang2-EVs can promote microglia/macrophages to phagocytose sphingomyelin, promote axon remyelination and axon elongation, and maintain the integrity of the blood-spinal barrier. Since Ang2 can also target the blood-brain barrier, we found that M-Ang2-EVs can also reduce brain inflammation that results from spinal cord injury. Our study applied the Angiopep-2 peptide to spinal cord injury to enhance the targeting of injured cells, and successfully construct engineered extracellular vesicles that can target the spinal cord injury site and the brain.

Increased unedited Alu RNA patterns found in cortex extracellular vesicles in Alzheimer's disease resemble hippocampus vasculature Alu RNA editing patterns but not cortex Alu RNA editing patterns

BACKGROUND

Endogenous Alu RNAs form double-stranded RNAs recognized by double-stranded RNA sensors and activate IRF and NF-kB transcriptional paths and innate immunity. Deamination of adenosines to inosines by the ADAR family of enzymes, a process termed A-to-I editing, disrupts double-stranded RNA structure and prevents innate immune activation. Innate immune activation is observed in Alzheimer's disease, the most common form of dementia. We have previously reported loss of A-to-I editing in hippocampus vasculature, but no change in cortex or cortex vasculature, associated with Alzheimer's disease.

OBJECTIVE

Here, we investigated the status of Alu RNA A-to-I editing in cortex extracellular vesicles in Alzheimer's disease.

METHODS

We used existing RNA-seq data sets and the SPRINT software package to determine levels of Alu RNA A-to-I editing in cortex extracellular vesicles in Alzheimer's disease and control groups and compared these editing profiles to those found in both total cortex and hippocampus vasculature.

RESULTS

We find substantial loss of Alu A-to-I editing in cortex extracellular vesicles in Alzheimer's disease. By measuring editing patterns on a gene-by-gene basis, we determined that editing patterns in cortex extracellular vesicles resemble editing patterns in hippocampus vasculature rather than total cortex.

CONCLUSIONS

We conclude that hippocampus vasculature unedited Alu RNAs are packaged in extracellular vesicles, travel to the cortex, deliver their cargo and stimulate innate immunity and alter other basic biological processes contributing to Alzheimer's disease progression.

Recent advances in development and delivery of non-viral nucleic acid therapeutics for brain tumor therapy

High grade gliomas (HGG) are a group of CNS tumors refractory to currently existing therapies, which routinely leads to early recurrence and a dismal prognosis. Recent advancements in nucleic acid-based therapy using a wide variety of different molecular targets and non-viral nanocarrier systems suggest that this approach holds significant potential to meet the urgent demand for improved therapeutic options for the treatment of these tumors. This review provides a comprehensive and up-to-date overview on the current landscape and progress of preclinical and clinical developments in this rapidly evolving and exciting field of research, including optimized nanocarrier delivery systems, promising therapeutic targets and tailor-made therapeutic strategies for individualized HGG patient treatment.

Plasma extracellular vesicle neurofilament light chain as the biomarkers of the progression of Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by progressive symptoms, underscoring the urgent need for predictive blood biomarkers. Plasma extracellular vesicles (EVs) offer a promising platform for biomarker development, with neurofilament light chain (NfL) emerging as a potential candidate for neurological diseases. This study evaluated plasma EV NfL as a biomarker for disease progression in a PD cohort.A total of 55 patients with PD (PwP) and 58 healthy controls (HCs) were followed, with PwP completing an average of 3.96 visits and HCs 2.25 visits. Plasma EVs were isolated and validated, and EV NfL levels were measured using an immunomagnetic reduction assay. Generalized estimating equations and Spearman correlations assessed relationships between clinical symptom progression and biomarkers. Although no significant differences in plasma EV NfL levels were observed between PwP and HCs over time, changes in plasma EV NfL significantly correlated with motor symptom progression, specifically with adjusted-total and akinetic-rigidity subscores of the Unified PD Rating Scale (UPDRS) Part III. Additionally, changes in UPDRS Part II scores were significantly associated with plasma EV NfL levels. These findings suggest that plasma EV NfL reflects motor symptom progression in PwP, highlighting its potential as a valuable biomarker for monitoring disease progression and guiding clinical trials in PD.

Molecular profiling of neuronal extracellular vesicles reveals brain tissue specific signals

Extracellular vesicles (EVs) released by neurons (nEVs) provide an opportunity to measure biomarkers from the brain circulating in the periphery. No study yet has directly compared molecular cargo in brain tissue to nEVs found in circulation in humans. We compared the levels microRNAs and environmental chemicals because microRNAs are one of the most studied nEV cargoes and offer great potential as biomarkers and environmental chemical load in nEVs is understudied and could reveal levels of chemicals in the brain. To do so, we leveraged matched sets of brain tissue and serum, and isolated serum total EVs and serum nEVs. We also generated and compared metabolomic profiles in a different set of matched serum, serum total EVs, and serum nEVs since metabolite cargo in nEVs is also understudied but could offer potential biomarkers. Highly expressed brain tissue miRNAs showed stronger correlations with nEVs than serum or total EVs. We detected several environmental chemical pollutant classes in nEVs. The chemical pollutant concentrations in nEVs were more strongly correlated with brain tissue levels than those observed between brain tissue and serum or total EVs. We also detected several endogenous metabolite classes in nEVs. Compared to serum and total EVs, there was enrichment of metabolites with known signaling roles, such as bile acids, oleic acid, phosphatidylserine, and isoprenoids. We provide evidence that nEV cargo is closely correlated to brain tissue content, further supporting their utility as a brain liquid biopsy.

Amniotic fluid stem cell extracellular vesicles as a novel fetal therapy for pulmonary hypoplasia: a review on mechanisms and translational potential

Disruption of developmental processes affecting the fetal lung leads to pulmonary hypoplasia. Pulmonary hypoplasia results from several conditions including congenital diaphragmatic hernia (CDH) and oligohydramnios. Both entities have high morbidity and mortality, and no effective therapy that fully restores normal lung development. Hypoplastic lungs have impaired growth (arrested branching morphogenesis), maturation (decreased epithelial/mesenchymal differentiation), and vascularization (endothelial dysfunction and vascular remodeling leading to postnatal pulmonary hypertension). Herein, we discuss the pathogenesis of pulmonary hypoplasia and the role of microRNAs (miRNAs) during normal and pathological lung development. Since multiple cells and pathways are altered, the ideal strategy for hypoplastic lungs is to deliver a therapy that addresses all aspects of abnormal lung development. In this review, we report on a novel regenerative approach based on the administration of extracellular vesicles derived from amniotic fluid stem cells (AFSC-EVs). Specifically, we describe the effects of AFSC-EVs in rodent and human models of pulmonary hypoplasia, their mechanism of action via release of their cargo, including miRNAs, and their anti-inflammatory properties. We also compare cargo contents and regenerative effects of EVs from AFSCs and mesenchymal stromal cells (MSCs). Overall, there is compelling evidence that antenatal administration of AFSC-EVs rescues multiple features of fetal lung development in experimental models of pulmonary hypoplasia. Lastly, we discuss the steps that need to be taken to translate this promising EV-based therapy from the bench to the bedside. These include strategies to overcome barriers commonly associated with EV therapeutics and specific challenges related to stem cell-based therapies in fetal medicine.

Extracellular Vesicles as Tools for Crossing the Blood-Brain Barrier to Treat Lysosomal Storage Diseases

Extracellular vesicles (EVs) are nanosized, membrane-bound structures that have emerged as promising tools for drug delivery, especially in the treatment of lysosomal storage disorders (LSDs) with central nervous system (CNS) involvement. This review highlights the unique properties of EVs, such as their biocompatibility, capacity to cross the blood-brain barrier (BBB), and potential for therapeutic cargo loading, including that of enzymes and genetic material. Current therapies for LSDs, like enzyme replacement therapy (ERT), often fail to address neurological symptoms due to their inability to cross the BBB. EVs offer a viable alternative, allowing for targeted delivery to the CNS and improving therapeutic outcomes. We discuss recent advancements in the engineering and modification of EVs to enhance targeting, circulation time and cargo stability, and provide a detailed overview of their application in LSDs, such as Gaucher and Fabry diseases, and Sanfilippo syndrome. Despite their potential, challenges remain in scaling production, ensuring isolation purity, and meeting regulatory requirements. Future developments will focus on overcoming these barriers, paving the way for the clinical translation of EV-based therapies in LSDs and other CNS disorders.

The Effect of Ionising Radiation on the Properties of Tumour-Derived Exosomes and Their Ability to Modify the Biology of Non-Irradiated Breast Cancer Cells-An In Vitro Study

The vast majority of breast cancer patients require radiotherapy but some of them will develop local recurrences and potentially metastases in the future. Recent data show that exosomal cargo is essential in these processes. Thus, we investigated the influence of ionising radiation on exosome properties and their ability to modify the sensitivity and biology of non-irradiated cells. Exosomes were isolated from breast cancer cell lines (MDA-MB-231, MCF7, and SKBR3) irradiated with 2 Gy (Exo 2 Gy) or no irradiation (Exo 0 Gy). Despite some differences in their molecular profiles, they did not affect cell viability, proliferation, cell cycle phase distribution, and radioresistance; however, both populations showed the ability to modify cell migration and invasion potential, as confirmed by the downregulation of β-catenin, which is responsible for maintaining the epithelial phenotype. Interestingly, exosomes from irradiated BCa cells were more actively deposited in the endothelial cells (EA.hy926). Furthermore, exosomes tend to lower the expression of CD31, which is responsible for maintaining intact vascularity. This preliminary study demonstrates the vital role of exosomes and their altered profile due to irradiation in the pathobiology of breast cancer.

Effects of small extracellular vesicles derived from normoxia- and hypoxia-treated prostate cancer cells on the submandibular salivary gland epithelium in vitro

Small extracellular vesicles (sEVs) are an important part of intercellular communication. They are phospholipid bilayer particles that carry active biomolecules such as proteins, various nucleic acids, and lipids. In recipient cells, sEVs can alter cellular functions, including cancer development and premetastatic niche formation in distant organs. Moreover, sEVs can carry cancer-specific features, which makes them promising biomarker candidates. However, the interactions of sEVs with biological barriers and consequences thereof, are not clarified yet. The blood-saliva barrier is crucial for preventing the entry of pathogens and (in)organic substances into the bloodstream, as well as molecule filtration from blood to saliva. The effects of brain derived DU145 prostate cancer (PCa) sEVs on a human submandibular salivary gland barrier (SSGB) in vitro were investigated. Small EVs were harvested from normoxic (N, atmospheric O2) or hypoxic (H, 1% O2) conditions, fluorescently labeled with CellTrackerTM Orange and thoroughly characterized. HTB-41 B2 cells were used as SSGB model cultured on 24-well ThinCert® inserts. After model optimization indicating effects of serum and serum-sEVs on barrier properties, PCa sEVs were applied to the basolateral (blood) side in either 10% serum, or serum-free conditions, and barrier integrity was continuously monitored for 40 hours. This study found that H and N PCa sEVs were uptaken by the SSGB in vitro model in similar quantities regardless of the media composition in the basolateral compartment. Permeation of fluorescent PCa sEVs into the apical compartment was not detectable with the applied methods. However, treatment with H and N sEVs under different serum conditions revealed distinct molecular clusters after hierarchical analysis of mRNA data measured by high-throughput qPCR, which were partly reflected at the protein level. For example, serum-reduction dependent decrease of barrier properties was accompanied with the decrease of CDH1 or Claudin-7 expression. Interestingly, the presence of H sEVs significantly increased the number of sEV-sized particles in the apical compartment of the SSGB model compared to basolaterally added N sEVs. This functional effect on the number of particles in the saliva (apical) compartment induced by different sEVs applied in the blood (basolateral) compartment might be a new approach to understand one possible mechanism how differences of salivary EVs might occur which then could be used as biomarker.

Platelet-derived extracellular vesicles in cardiovascular disease and treatment - from maintaining homeostasis to targeted drug delivery

PURPOSE OF REVIEW

Cardiovascular disease (CVD) remains a major global health burden. Rising incidences necessitate improved understanding of the pathophysiological processes underlying disease progression to foster the development of novel therapeutic strategies. Besides their well recognized role in CVD, platelet-derived extracellular vesicles (PEVs) mediate inter-organ cross talk and contribute to various inflammatory diseases.

RECENT FINDINGS

PEVs are readily accessible diagnostic biomarkers that mirror pathophysiological disease progression but also may confer cardioprotective properties. Monitoring the effects of modulation of PEV signatures through pharmacotherapies has also provided novel insights into treatment efficacy. Furthermore, exploiting their inherent ability to infiltrate thrombi, atherosclerotic plaques and solid tumours, PEVs as well as platelet-membrane coated nanoparticles are emerging as novel effective and targeted treatment options for CVD and cancer.

SUMMARY

Collectively, in-depth characterization of PEVs in various diseases ultimately enhances their use as diagnostic or prognostic biomarkers and potential therapeutic targets, making them clinically relevant candidates to positively impact patient outcomes.

Assessing platelet-derived extracellular vesicles for potential as therapeutic targets in cardiovascular diseases

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of death worldwide. Platelet-derived extracellular vesicles (PEV) have attracted extensive attention in cardiovascular disease research in recent years because their cargo is involved in a variety of pathophysiological processes, such as thrombosis, immune response, promotion or inhibition of inflammatory response, promotion of angiogenesis as well as cell proliferation and migration.

AREAS COVERED

This review explores the role of PEV in various cardiovascular diseases (such as atherosclerosis, myocardial infarction, ischemia-reperfusion injury, and heart failure), with relation to its molecular cargo (nucleic acids, bioactive lipids, proteins) and aims to provide new insights in the pathophysiologic role of PEV, and methods for preventing and treating cardiovascular diseases based on PEV.

EXPERT OPINION

Studies have shown that the cargo of PEV may be dysregulated during cardiovascular disease and delivery to tissues can result in detrimental pathophysiologic effects. Counteracting this process might have the potential to inhibit inflammation, promote angiogenesis, and inhibit cardiomyocyte death. In addition, PEV have potential as biocompatible and autologous drug carriers. Therefore, better research on the mechanisms how PEV act during cardiovascular disease and could be implemented as a therapeutic will provide new perspectives for the treatment of cardiovascular disease.

Cyclic Ruthenium-Peptide Prodrugs Penetrate the Blood-Brain Barrier and Attack Glioblastoma upon Light Activation in Orthotopic Zebrafish Tumor Models

The blood-brain barrier (BBB) presents one of the main obstacles to delivering anticancer drugs in glioblastoma. Herein, we investigated the potential of a series of cyclic ruthenium-peptide conjugates as photoactivated therapy candidates for the treatment of this aggressive tumor. The three compounds studied, Ru-p(HH), Ru-p(MH), and Ru-p(MM) ([Ru(Ph2phen)2 (Ac-X1RGDX2-NH2)]Cl2 with Ph2phen = 4,7-diphenyl-1,10-phenanthroline and X1, X2 = His or Met), include an integrin-targeted pentapeptide coordinated to a ruthenium warhead via two photoactivated ruthenium-X1,2 bonds. Their photochemistry, activation mechanism, tumor targeting, and antitumor activity were meticulously addressed. A combined in vitro and in vivo study revealed that the photoactivated cell-killing mechanism and their O2 dependence were strongly influenced by the nature of X1 and X2. Ru-p(MM) was shown to be a photoactivated chemotherapy (PACT) drug, while Ru-p(HH) behaved as a photodynamic therapy (PDT) drug. All conjugates, however, showed comparable antitumor targeting and efficacy toward human glioblastoma 3D spheroids and orthotopic glioblastoma tumor models in zebrafish embryos. Most importantly, in this model, all three compounds could effectively cross the BBB, resulting in excellent targeting of the tumors in the brain.

FMR1 Disorders: Basics of Biology and Therapeutics in Development

Fragile X Syndrome (FXS) presents with a constellation of phenotypes, including trouble regulating emotion and aggressive behaviors, disordered sleep, intellectual impairments, and atypical physical development. Genetic study of the X chromosome revealed that substantial repeat expansion of the 5' end of the gene fragile X messenger ribonucleoprotein 1 (FMR1) promoted DNA methylation and, consequently, silenced expression of FMR1. Further analysis proved that shorter repeat expansions in FMR1 also manifested in disease at later stages in life. Treatment and therapy options do exist, but they only manage symptoms. Up to now, no cure for FMR1 disorders exists. In this review, we aim to provide an overview of FMR1 biology and the latest research focused on developing therapeutic interventions that can potentially prevent and/or reverse FXS.

Adipose Tissue as a Major Launch Spot for Circulating Extracellular Vesicle-Carried MicroRNAs Coordinating Tissue and Systemic Metabolism

Circulating microRNAs (miRNAs), especially transported by extracellular vesicles (EVs), have recently emerged as major new participants in interorgan communication, playing an important role in the metabolic coordination of our tissues. Among these, adipose tissue displays an extraordinary ability to secrete a vast list of EV-carried miRNAs into the circulation, representing new hormone-like factors. Despite the limitations of current methodologies for the unequivocal identification of the origin and destination of EV-carried miRNAs in vivo, recent investigations clearly support the important regulatory role of adipose-derived circulating miRNAs in shaping the metabolism and function of other tissues including the liver, muscle, endocrine pancreas, cardiovascular system, gastrointestinal tract, and brain. Here, we review the most recent findings regarding miRNAs transported by adipose-derived EVs (AdEVs) targeting other major metabolic organs and the implications of this dialog for physiology and pathology. We also review here the current and potential future diagnostic and therapeutic applications of AdEV-carried miRNAs.

Brain-Periphery Axes: The Potential Role of Extracellular Vesicles-Delivered miRNAs

Bidirectional communication between the central nervous system (CNS) and peripheral organs and tissue has been widely documented in physiological and pathological conditions. This communication relies on the bilateral transmission of signaling molecules and substances that circulate throughout the body and reach their target site(s) via the blood and other biological fluids (e.g., the cerebrospinal fluid, the lymph). One of the mechanisms by which these molecular messengers are exchanged is through the secretion of extracellular vesicles (EVs). EVs are known to mediate cell-to-cell communication by delivering biological molecules, including nucleic acids, proteins, lipids, and various other bioactive regulators. Moreover, EVs can cross the blood-brain barrier (BBB), enabling direct communication between the periphery and the brain. In particular, the delivery of microRNAs (miRNAs) can modulate the expression profiles of recipient cells, thereby influencing their functions. This review synthesizes current findings about the brain-periphery cross-talk mediated by EVs-delivered miRNAs. Although this mechanism has been definitively shown in a few cases, much evidence indirectly indicates that it could mediate brain-peripherical organs/tissue communication, especially in pathological conditions. Therefore, understanding this process could provide valuable insights for the treatment and management of neurological and systemic diseases.

Extracellular Vesicles and Their Applications in Tumor Diagnostics and Immunotherapy

Extracellular vesicles (EVs) are cell-derived nanoparticles that have attracted significant attention in the investigation of human health and disease, including cancer biology and its clinical management. Concerning cancer, EVs have been shown to influence numerous aspects of oncogenesis, including tumor proliferation and metastasis. EVs can augment the immune system and have been implicated in virtually all aspects of innate and adaptive immunity. With immunotherapy changing the landscape of cancer treatment across multiple disease sites, it is paramount to understand their mechanisms of action and to further improve upon their efficacy. Despite a rapidly growing body of evidence supporting of the utility of EVs in cancer diagnostics and therapeutics, their application in clinical trials involving solid tumors and immunotherapy remains limited. To date, relatively few trials are known to incorporate EVs in this context, mainly employing them as biomarkers. To help address this gap, this review summarizes known applications of EVs in clinical trials and provides a brief overview of the roles that EVs play in cancer biology, immunology, and their proposed implications in immunotherapy. The impetus to leverage EVs in future clinical trials and correlative studies is crucial, as they are ideally positioned to synergize with advancements in multi-omics research to further therapeutic discovery and our understanding of cancer biology.

Development and Biological Characterization of Cancer Biomimetic Membrane Nanovesicles for Enhancing Therapy Efficacy in Human Glioblastoma Cells

As nanocarriers of a new generation, biomimetic nanovesicles are an emerging class of therapeutic tools whose surface is integrated or fabricated with biomaterials capable of mimicking the biological features and functions of native cells. Thanks to this, biomimetic nanovesicles, in particular, those made by plasma membrane moieties, possess greatly improved biocompatibility, high target specificity, a long retention time, and minimal undesired immune responses. For these reasons, a multitude of progenitor cells including cancer ones were employed as templates to generate biomimetic or membrane-camouflaged nanovesicles hosting different therapeutic compounds. In this contribution, different membrane-derived biomimetic vesicles (M-NVs) were generated by osmotic lysis or plasma membrane isolation approaches from normal and cancer cell lines and assayed against in vitro models of human glioblastoma. M-NVs were compared in their cellular internalization degrees of DNA and proteins, morphologically and molecularly characterized, expressing an extracellular membrane-associated marker. Then, Rose Bengal (RB), a photoactivable drug characterized by a relatively low cellular uptake, was incorporated into nascent glioblastoma-derived M-NVs and finally administered to homotypic receiving cells, showing an increased degree of internalization as well as induced cytotoxic effects, even in the absence of photodynamic direct stimulation. Similar results were also obtained assaying lyophilized M-NVs loaded with RB. In conclusion, M-NVs generated by cell membranes effectively deliver several cargoes, including therapeutic molecules, maintain functionality after lyophilization, and show significant internalization effects, making them a promising strategy for therapeutic applications against human glioblastoma cells.

Efficient enzyme-free isolation of brain-derived extracellular vesicles

Extracellular vesicles (EVs) have gained significant attention as pathology mediators and potential diagnostic tools for neurodegenerative diseases. However, isolation of brain-derived EVs (BDEVs) from tissue remains challenging, often involving enzymatic digestion steps that may compromise the integrity of EV proteins and overall functionality. Here, we describe that collagenase digestion, commonly used for BDEV isolation, produces undesired protein cleavage of EV-associated proteins in brain tissue homogenates and cell-derived EVs. In order to avoid this effect, we studied the possibility of isolating BDEVs with a reduced amount of collagenase or without any protease. Characterization of the isolated BDEVs from mouse and human samples (both female and male) revealed their characteristic morphology and size distribution with both approaches. However, we show that even minor enzymatic digestion induces 'artificial' proteolytic processing in key BDEV markers, such as Flotillin-1, CD81, and the cellular prion protein (PrPC), whereas avoiding enzymatic treatment completely preserves their integrity. We found no major differences in mRNA and protein content between non-enzymatically and enzymatically isolated BDEVs, suggesting that the same BDEV populations are purified with both approaches. Intriguingly, the lack of Golgi marker GM130 signal, often referred to as contamination indicator (or negative marker) in EV preparations, seems to result from enzymatic digestion rather than from its actual absence in BDEV samples. Overall, we show that non-enzymatic isolation of EVs from brain tissue is possible and avoids artificial pruning of proteins while achieving an overall high BDEV yield and purity. This protocol will help to understand the functions of BDEV and their associated proteins in a near-physiological setting, thus opening new research approaches.

The Cervical and Meningeal Lymphatic Network as a Pathway for Retrograde Nanoparticle Transport to the Brain

Introduction

The meningeal lymphatic vessels have been described as a pathway that transports cerebrospinal fluid and interstitial fluid in a unidirectional manner towards the deep cervical lymph nodes. However, these vessels exhibit anatomical and molecular characteristics typical of initial lymphatic vessels, with the absence of surrounding smooth muscle and few or absent valves. Given its structure, this network could theoretically allow for bidirectional motion. Nevertheless, it has not been assessed as a potential route for nanoparticles to travel from peripheral tissues to the brain.

Methods

We employed superparamagnetic iron oxide nanoparticles (SPIONs), exosomes loaded with SPIONs, gold nanorods, and Chinese ink nanoparticles. SPIONs were prepared via chemical coprecipitation, while exosomes were isolated from the B16F10 melanoma cell line through the Exo-Spin column protocol and loaded with SPIONs through electroporation. Gold nanorods were functionalized with polyethylene glycol. We utilized C57BL/6 mice for post-mortem and in vivo procedures. To evaluate the retrograde directional flow, we injected each nanoparticle solution in the deep cervical lymph node. The head and neck were fixed for magnetic resonance imaging and histological analysis.

Results

Here we show that extracellular vesicles derived from the B16F10 melanoma cell line, along with superparamagnetic iron oxide nanoparticles, gold nanorods, and Chinese ink nanoparticles can reach the meningeal lymphatic vessels and the brain of C57BL/6 mice after administration within the deep cervical lymph nodes post-mortem and in vivo, exclusively through lymphatic structures.

Discussion

The functional anatomy of dural lymphatics has been found to be conserved between mice and humans, suggesting that our findings may have significant implications for advancing targeted drug delivery systems using nanoparticles. Understanding the retrograde transport of nanoparticles through the meningeal lymphatic network could lead to novel therapeutic approaches in nanomedicine, offering new insights into fluid dynamics in both physiological and neuropathological contexts. Further research into this pathway may unlock new strategies for treating neurological diseases or enhancing drug delivery to the brain.

Microglia morphological response to mesenchymal stromal cell extracellular vesicles demonstrates EV therapeutic potential for modulating neuroinflammation

BACKGROUND

Mesenchymal stromal cell derived extracellular vesicles (MSC-EVs) are a promising therapeutic for neuroinflammation. MSC-EVs can interact with microglia, the resident immune cells of the brain, to exert their immunomodulatory effects. In response to inflammatory cues, such as cytokines, microglia undergo phenotypic changes indicative of their function e.g. morphology and secretion. However, these changes in response to MSC-EVs are not well understood. Additionally, no disease-relevant screening tools to assess MSC-EV bioactivity exist, which has further impeded clinical translation. Here, we developed a quantitative, high throughput morphological profiling approach to assess the response of microglia to neuroinflammation- relevant signals and whether this morphological response can be used to indicate the bioactivity of MSC-EVs.

RESULTS

Using an immortalized human microglia cell-line, we observed increased size (perimeter, major axis length) and complexity (form factor) upon stimulation with interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). Upon treatment with MSC-EVs, the overall morphological score (determined using principal component analysis) shifted towards the unstimulated morphology, indicating that MSC-EVs are bioactive and modulate microglia. The morphological effects of MSC-EVs in TNF-α /IFN-γ stimulated cells were concomitant with reduced secretion of 14 chemokines/cytokines (e.g. CXCL6, CXCL9) and increased secretion of 12 chemokines/cytokines (e.g. CXCL8, CXCL10). Proteomic analysis of cell lysates revealed significant increases in 192 proteins (e.g. HIBADH, MEAK7, LAMC1) and decreases in 257 proteins (e.g. PTEN, TOM1, MFF) with MSC-EV treatment. Of note, many of these proteins are involved in regulation of cell morphology and migration. Gene Set Variation Analysis revealed upregulation of pathways associated with immune response, such as regulation of cytokine production, immune cell infiltration (e.g. T cells, NK cells) and morphological changes (e.g. Semaphorin, RHO/Rac signaling). Additionally, changes in microglia mitochondrial morphology were measured suggesting that MSC-EV modulate mitochondrial metabolism.

CONCLUSION

This study comprehensively demonstrates the effects of MSC-EVs on human microglial morphology, cytokine secretion, cellular proteome, and mitochondrial content. Our high-throughput, rapid, low-cost morphometric approach enables screening of MSC-EV batches and manufacturing conditions to enhance EV function and mitigate EV functional heterogeneity in a disease relevant manner. This approach is highly generalizable and can be further adapted and refined based on selection of the disease-relevant signal, target cell, and therapeutic product.

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.

Differential Protein Expression in Extracellular Vesicles Defines Treatment Responders and Non-Responders in Multiple Sclerosis

Multiple sclerosis (MS) remains the leading cause of neurological disability among young adults worldwide, underscoring the urgent need to define the best therapeutic strategy. Recent advances in proteomics have deepened our understanding of treatment mechanisms and revealed promising biomarkers for predicting therapeutic outcomes. This study focuses on the identification of a protein profile of circulating extracellular vesicles (EVs) derived from neurons, oligodendrocytes, and B and T cells able to differentiate treatment responders and non-responders in 80 patients with MS. In the patients who responded to treatment, T cell-derived EVs were enriched in LV151, a protein involved in the promotion of anti-inflammatory cytokines, whereas Bcell-derived EVs showed elevated PSMD6 and PTPRC, related to immunoproteasome function. Oligodendrocyte- and neuron-derived EVs showed upregulated CO6A1 and COEA1, involved in extracellular matrix reorganisation, as well as LAMA5, NonO, SPNT, and NCAM, which are critical for brain repair. In contrast, non-responders showed higher levels of PSMD7 and PRS10 from B cell-derived EVs, associated with DNA damage, and increased levels of PERM and PERL from T cell-derived EVs, linked to nuclear factor kappa B activation and drug-resistant proteins such as HS90A and RASK. These findings highlight a distinct panel of proteins in EVs that could serve as an early indicator of treatment efficacy in MS.

Therapeutic delivery of recombinant glucocerebrosidase enzyme-containing extracellular vesicles to human cells from Gaucher disease patients

BACKGROUND

Gaucher disease (GD) is one of the most common types of lysosomal storage diseases (LSDs) caused by pathogenic variants of lysosomal β-glucocerebrosidase gene (GBA1), resulting in the impairment of Glucocerebrosidase (GCase) enzyme function and the accumulation of a glycolipid substrate, glucosylceramide (GlcCer) within lysosomes. Current therapeutic approaches such as enzyme replacement therapy and substrate reduction therapy cannot fully rescue GD pathologies, especially neurological symptoms. Meanwhile, delivery of lysosomal enzymes to the endocytic compartment of affected human cells is a promising strategy for treating neuropathic LSDs.

RESULT

Here, we describe a novel approach to restore GCase enzyme in cells from neuropathic GD patients by producing extracellular vesicle (EVs)-containing GCase from cells overexpressing GBA1 gene. Lentiviral vectors containing modified GBA1 were introduced into HEK293T cells to produce a stable cell line that provides a sustainable source of functional GCase enzyme. The GBA1-overexpressing cells released EV-containing GCase enzyme, that is capable of entering into and localizing in the endocytic compartment of recipient cells, including THP-1 macrophage, SH-SY5Y neuroblastoma, and macrophages and neurons derived from induced pluripotent stem cells (iPSCs) of neuropathic GD patients. Importantly, the recipient cells exhibit higher GCase enzyme activity.

CONCLUSION

This study presents a promising therapeutic strategy to treat severe types of LSDs. It involves delivering lysosomal enzymes to the endocytic compartment of human cells affected by conditions such as GDs with neurological symptoms, as well as potentially other neurological disorders impacting lysosomes.

The potential of exosomes as a new therapeutic strategy for glioblastoma

Glioblastoma (GBM) stands for the most common and aggressive type of brain tumour in adults. It is highly invasive, which explains its short rate of survival. Little is known about its risk factors, and current therapy is still ineffective. Hence, efforts are underway to develop novel and effective treatment approaches against this type of cancer. Exosomes are being explored as a promising strategy for conveying and delivering therapeutic cargo to GBM cells. They can fuse with the GBM cell membrane and, consequently, serve as delivery systems in this context. Due to their nanoscale size, exosomes can cross the blood-brain barrier (BBB), which constitutes a significant hurdle to most chemotherapeutic drugs used against GBM. They can subsequently inhibit oncogenes, activate tumour suppressor genes, induce immune responses, and control cell growth. However, despite representing a promising tool for the treatment of GBM, further research and clinical studies regarding exosome biology, engineering, and clinical applications still need to be completed. Here, we sought to review the application of exosomes in the treatment of GBM through an in-depth analysis of the scientific and clinical studies on the entire process, from the isolation and purification of exosomes to their design and transformation into anti-oncogenic drug delivery systems. Surface modification of exosomes to enhance BBB penetration and GBM-cell targeting is also a topic of discussion.

Current Advances and Future Perspectives on Mesenchymal Stem Cell-Derived Extracellular Vesicles in Alzheimer's Disease

The incidence of Alzheimer's disease (AD) has been increasing in recent years as the world's population ages, which poses a significant challenge to public health. Due to the complexity of pathogenesis of AD, currently there is no effective treatment for it. In recent years, cell and gene therapy has attracted widespread attention in the treatment of neurodegenerative diseases. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) represent a novel cell-free therapy with numerous advantages over cell-based therapies owing to their low immunogenicity and high safety profile. We summarize recent progress in the application of EVs for treating AD and the specific mechanisms and outline the underlying mechanisms. We also explore various methods for optimizing the function of MSC-EVs, including gene editing, modifying stem cell culture conditions and peptide modification. In addition, we discuss the therapeutic potentials of MSC-EVs, as well as the obstacles that currently impede their clinical utilization.

Age affects the association of red blood cell indices with efficacy of remote ischemic conditioning in patients with acute moderate ischemic stroke

We conducted a post hoc analysis of Remote Ischemic Conditioning for Acute Moderate Ischemic Stroke (RICAMIS) to investigate whether red blood cell (RBC) indices are associated with efficacy of remote ischemic conditioning (RIC), and whether the association is affected by age. In this post hoc analysis, patients with RBC indices at admission were enrolled. RBC indices including RBC count, hematocrit (HCT), mean corpuscular volume (MCV), hemoglobin (HB), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were analyzed. According to the median of these RBC indices, eligible patients were divided into high and low groups, which were further subdivided into RIC and control subgroups. Primary endpoint was excellent functional outcome defined as a modified Rankin Scale score of 0-1 at 90 days, which was used to evaluate RIC efficacy. RIC efficacy as well as effect of age on RIC efficacy were analyzed across the high and low groups of different RBC indices, and the interaction effects of RBC indices on RIC efficacy were evaluated. A total of 1640 patients were enrolled in the final analysis. In overall patients, no significant interaction effects of RIC intervention by all RBC indices were found, although there was a trend in interaction effect of RIC intervention by MCH (p = 0.116). However, we found an effect of age on the association of MCH with RIC efficacy. In patients over 60 years old, MCH significantly affected RIC efficacy (p = 0.006) and RIC significantly produced a higher proportion of primary outcome in high MCH (72.6% vs. 59.1%, P < 0.001) vs. low MCH group (61.2% vs. 62%, P = 0.829), which was not identified in patients under 60 years old. Furthermore, RIC efficacy decreased with increasing age in patients with low MCH with significant interaction effect (p = 0.012), while RIC efficacy increased with increasing age in patients with high MCH although no significant interaction (p = 0.126). No significant interaction effects of RIC intervention by RBC count, HCT, MCV, HB, and MCHC were found regardless of age. This secondary analysis of RICAMIS suggested that RIC exhibited more obvious benefit in AIS patients over 60 years old with high MCH compared with those with low MCH group, but RBC count, HCT, MCV, HB, and MCHC were not associated with the efficacy of RIC treatment regardless of age.

Green Onion-Derived Exosome-like Nanoparticles Prevent Ferroptotic Cell Death Triggered by Glutamate: Implication for GPX4 Expression

In recent years, alongside research on mammalian-derived exosomes, there has been increasing interest in the physiological activities of plant-derived exosome-like nanoparticles (PDEN). The biocompatibility, minimal side effects, and diverse bioactive ingredients contained in PDEN make them valuable as potential therapeutic agents for an extensive range of diseases. In this study, we cost-effectively isolated exosome-like nanoparticles from green onion (Allium fistulosum) using polyethylene glycol and examined their biological activity in HT-22 cells exposed to glutamate. The isolated green onion-derived exosome-like nanoparticle (GDEN) had an average diameter of 167.4 nm and a zeta potential of -16.06 mV. GDEN effectively inhibited glutamate-induced Ca2+ influx and lipid peroxidation, thereby preventing ferroptotic cell death in HT-22 mouse hippocampal cells. Additionally, GDEN reduced the intracellular iron accumulation by modulating the expression of proteins associated with iron metabolism, including transferrin receptor 1, ferroportin 1, divalent metal transporter 1, and ferritin. Notably, GDEN upregulated the expression of glutathione peroxidase 4, a potent antioxidant protein involved in ferroptosis, along with an increase in glutathione synthesis. These findings indicate that GDENs have the potential to serve as bioactives from natural sources against glutamate-induced neuronal cell death, like ferroptosis. This study advances the investigation into the potential medical applications of GDEN and may provide a new approach for the utilization of these bioactive components against neuronal disorders.

The complexity of extracellular vesicles: Bridging the gap between cellular communication and neuropathology

Brain-derived extracellular vesicles (EVs) serve a prominent role in maintaining homeostasis and contributing to pathology in health and disease. This review establishes a crucial link between physiological processes leading to EV biogenesis and their impacts on disease. EVs are involved in the clearance and transport of proteins and nucleic acids, responding to changes in cellular processes associated with neurodegeneration, including autophagic disruption, organellar dysfunction, aging, and other cell stresses. In neurodegenerative disorders (e.g., Alzheimer's disease, Parkinson's disease, etc.), EVs contribute to the spread of pathological proteins like amyloid β, tau, ɑ-synuclein, prions, and TDP-43, exacerbating neurodegeneration and accelerating disease progression. Despite evidence for both neuropathological and neuroprotective effects of EVs, the mechanistic switch between their physiological and pathological functions remains elusive, warranting further research into their involvement in neurodegenerative disease. Moreover, owing to their innate ability to traverse the blood-brain barrier and their ubiquitous nature, EVs emerge as promising candidates for novel diagnostic and therapeutic strategies. The review uniquely positions itself at the intersection of EV cell biology, neurophysiology, and neuropathology, offering insights into the diverse biological roles of EVs in health and disease.

Evolving insights into erythrocytes in synucleinopathies

Synucleinopathies, including Parkinson's disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB), are characterized by neuronal loss accompanied by α-synuclein (α-syn) accumulation in the brain. While research conventionally focused on brain pathology, there is growing interest in peripheral alterations. Erythrocytes, which are rich in α-syn, have emerged as a compelling site for synucleinopathies-related alterations. Erythrocyte-derived extracellular vesicles (EVs), containing pathological α-syn species, can traverse the blood-brain barrier (BBB) under certain conditions and the gastrointestinal tract, where α-syn and gut microbiota interact extensively. This review explores the accumulating evidence of erythrocyte involvement in synucleinopathies, as well as their potential in disease pathogenesis and diagnosis. Given their unique properties, erythrocytes and erythrocyte-derived EVs may also serve as an ideal therapeutic platform for treating synucleinopathies and beyond.

Vascularized platforms for investigating cell communication via extracellular vesicles

The vascular network plays an essential role in the maintenance of all organs in the body via the regulated delivery of oxygen and nutrients, as well as tissue communication via the transfer of various biological signaling molecules. It also serves as a route for drug administration and affects pharmacokinetics. Due to this importance, engineers have sought to create physiologically relevant and reproducible vascular systems in tissue, considering cell-cell and extracellular matrix interaction with structural and physical conditions in the microenvironment. Extracellular vesicles (EVs) have recently emerged as important carriers for transferring proteins and genetic material between cells and organs, as well as for drug delivery. Vascularized platforms can be an ideal system for studying interactions between blood vessels and EVs, which are crucial for understanding EV-mediated substance transfer in various biological situations. This review summarizes recent advances in vascularized platforms, standard and microfluidic-based techniques for EV isolation and characterization, and studies of EVs in vascularized platforms. It provides insights into EV-related (patho)physiological regulations and facilitates the development of EV-based therapeutics.

Cell-specific expression of key mitochondrial enzymes limits OXPHOS in astrocytes of the adult human neocortex and hippocampal formation

The astrocyte-to-neuron lactate shuttle model entails that, upon glutamatergic neurotransmission, glycolytically derived pyruvate in astrocytes is mainly converted to lactate instead of being entirely catabolized in mitochondria. The mechanism of this metabolic rewiring and its occurrence in human brain are unclear. Here by using immunohistochemistry (4 brains) and imaging mass cytometry (8 brains) we show that astrocytes of the adult human neocortex and hippocampal formation express barely detectable amounts of mitochondrial proteins critical for performing oxidative phosphorylation (OXPHOS). These data are corroborated by queries of transcriptomes (107 brains) of neuronal versus non-neuronal cells fetched from the Allen Institute for Brain Science for genes coding for a much larger repertoire of entities contributing to OXPHOS, showing that human non-neuronal elements barely expressed mRNAs coding for such proteins. With less OXPHOS, human brain astrocytes are thus bound to produce more lactate to avoid interruption of glycolysis.

Therapeutic potential of extracellular vesicles derived from human amniotic epithelial cells for perinatal cerebral and pulmonary injury

Lung and brain injury that occurs during the perinatal period leads to lifelong disability and is often driven and/or exacerbated by inflammation. Human amniotic epithelial cells (hAEC), which demonstrate immunomodulatory, anti-fibrotic, and regenerative capabilities, are being explored as a therapeutic candidate for perinatal injury. However, limitations regarding scalable manufacturing, storage, transport, and dose-related toxicity have impeded clinical translation. Isolated therapeutic extracellular vesicles (EVs) from stem and stem-like cells are thought to be key paracrine mediators of therapeutic efficacy. The unique characteristics of EVs suggest that they potentially circumvent the limitations of traditional cell-based therapies. However, given the novelty of EVs as a therapeutic, recommendations around ideal methods of production, isolation, storage, and delivery have not yet been created by regulatory agencies. In this concise review, we discuss the pertinence and limitations of cell-based therapeutics in perinatal medicine. We also review the preclinical evidence supporting the use of therapeutic EVs for perinatal therapy. Further, we summarize the arising considerations regarding adequate cell source, biodistribution, isolation and storage methods, and regulatory roadblocks for the development of therapeutic EVs.

Beyond Blood Clotting: The Many Roles of Platelet-Derived Extracellular Vesicles

Platelet-derived extracellular vesicles (pEVs) are emerging as pivotal players in numerous physiological and pathological processes, extending beyond their traditional roles in hemostasis and thrombosis. As one of the most abundant vesicle types in human blood, pEVs transport a diverse array of bioactive molecules, including growth factors, cytokines, and clotting factors, facilitating crucial intercellular communication, immune regulation, and tissue healing. The unique ability of pEVs to traverse tissue barriers and their biocompatibility position them as promising candidates for targeted drug delivery and regenerative medicine applications. Recent studies have underscored their involvement in cancer progression, viral infections, wound healing, osteoarthritis, sepsis, cardiovascular diseases, rheumatoid arthritis, and atherothrombosis. For instance, pEVs promote tumor progression and metastasis, enhance tissue repair, and contribute to thrombo-inflammation in diseases such as COVID-19. Despite their potential, challenges remain, including the need for standardized isolation techniques and a comprehensive understanding of their mechanisms of action. Current research efforts are focused on leveraging pEVs for innovative anti-cancer treatments, advanced drug delivery systems, regenerative therapies, and as biomarkers for disease diagnosis and monitoring. This review highlights the necessity of overcoming technical hurdles, refining isolation methods, and establishing standardized protocols to fully unlock the therapeutic potential of pEVs. By understanding the diverse functions and applications of pEVs, we can advance their use in clinical settings, ultimately revolutionizing treatment strategies across various medical fields and improving patient outcomes.

Microphysiological Blood-Brain Barrier Systems for Disease Modeling and Drug Development

The blood-brain barrier (BBB) is a highly controlled microenvironment that regulates the interactions between cerebral blood and brain tissue. Due to its selectivity, many therapeutics targeting various neurological disorders are not able to penetrate into brain tissue. Pre-clinical studies using animals and other in vitro platforms have not shown the ability to fully replicate the human BBB leading to the failure of a majority of therapeutics in clinical trials. However, recent innovations in vitro and ex vivo modeling called organs-on-chips have shown the potential to create more accurate disease models for improved drug development. These microfluidic platforms induce physiological stressors on cultured cells and are able to generate more physiologically accurate BBBs compared to previous in vitro models. In this review, different approaches to create BBBs-on-chips are explored alongside their application in modeling various neurological disorders and potential therapeutic efficacy. Additionally, organs-on-chips use in BBB drug delivery studies is discussed, and advances in linking brain organs-on-chips onto multiorgan platforms to mimic organ crosstalk are reviewed.