Surface-modified engineered exosomes attenuated cerebral ischemia/reperfusion injury by targeting the delivery of quercetin towards impaired neurons

Exosomes as therapeutic and drug delivery vehicle for neurodegenerative diseases

Neurodegenerative disorders are complex, progressive, and life-threatening. They cause mortality and disability for millions of people worldwide. Appropriate treatment for neurodegenerative diseases (NDs) is still clinically lacking due to the presence of the blood-brain barrier (BBB). Developing an effective transport system that can cross the BBB and enhance the therapeutic effect of neuroprotective agents has been a major challenge for NDs. Exosomes are endogenous nano-sized vesicles that naturally carry biomolecular cargoes. Many studies have indicated that exosome content, particularly microRNAs (miRNAs), possess biological activities by targeting several signaling pathways involved in apoptosis, inflammation, autophagy, and oxidative stress. Exosome content can influence cellular function in healthy or pathological ways. Furthermore, since exosomes reflect the features of the parental cells, their cargoes offer opportunities for early diagnosis and therapeutic intervention of diseases. Exosomes have unique characteristics that make them ideal for delivering drugs directly to the brain. These characteristics include the ability to pass through the BBB, biocompatibility, stability, and innate targeting properties. This review emphasizes the role of exosomes in alleviating NDs and discusses the associated signaling pathways and molecular mechanisms. Furthermore, the unique biological features of exosomes, making them a promising natural transporter for delivering various medications to the brain to combat several NDs, are also discussed.

Advancing stroke therapy: innovative approaches with stem cell-derived extracellular vesicles

Stroke is a leading cause of mortality and long-term disability globally, with acute ischemic stroke (AIS) being the most common subtype. Despite significant advances in reperfusion therapies, their limited time window and associated risks underscore the necessity for novel treatment strategies. Stem cell-derived extracellular vesicles (EVs) have emerged as a promising therapeutic approach due to their ability to modulate the post-stroke microenvironment and facilitate neuroprotection and neurorestoration. This review synthesizes current research on the therapeutic potential of stem cell-derived EVs in AIS, focusing on their origin, biogenesis, mechanisms of action, and strategies for enhancing their targeting capacity and therapeutic efficacy. Additionally, we explore innovative combination therapies and discuss both the challenges and prospects of EV-based treatments. Our findings reveal that stem cell-derived EVs exhibit diverse therapeutic effects in AIS, such as promoting neuronal survival, diminishing neuroinflammation, protecting the blood-brain barrier, and enhancing angiogenesis and neurogenesis. Various strategies, including targeting modifications and cargo modifications, have been developed to improve the efficacy of EVs. Combining EVs with other treatments, such as reperfusion therapy, stem cell transplantation, nanomedicine, and gut microbiome modulation, holds great promise for improving stroke outcomes. However, challenges such as the heterogeneity of EVs and the need for standardized protocols for EV production and quality control remain to be addressed. Stem cell-derived EVs represent a novel therapeutic avenue for AIS, offering the potential to address the limitations of current treatments. Further research is needed to optimize EV-based therapies and translate their benefits to clinical practice, with an emphasis on ensuring safety, overcoming regulatory hurdles, and enhancing the specificity and efficacy of EV delivery to target tissues.

Chondroitin sulfate-tocopherol succinate modified exosomes for targeted drug delivery to CD44-positive cancer cells

Exosomes (Exos), natural nanovesicles released by various cell types, show potential as an effective drug delivery platform due to their intrinsic role as transporters of biomolecules between different cells. However, Exos functionalization with targeting ligands is a critical step to enhance their targeting capability, which could be challenging. In this study, Exos were modified to specifically bind to CD44-positive cells by anchoring chondroitin sulfate (CS) to their surface. Exo modification was facilitated with CS conjugation with alpha-tocopherol succinate (TOS) as an anchorage. The modified Exos were utilized for delivering curcumin (Cur) to pancreatic cancer (PC) cells. In vitro Cur release studies revealed that Exos play a crucial role in maintaining Cur within themselves, demonstrating their potential as effective carriers for drug delivery to targeted locations. Notably, Cur loaded into the modified Exos exhibited enhanced cytotoxicity compared to unmodified Exo-Cur. Meanwhile, Exo-Cur-TOS-CS induced apoptosis more effectively in AsPC-1 cells than unmodified Exos (70.2 % versus 56.9 %). It is worth mentioning that with CD44-mediated cancer-specific targeting, Exo-CS enabled increased intracellular accumulation in AsPC-1 cells, showing promise as a targeted platform for cancer therapy. These results confirm that Exo modification has a positive impact on enhancing the therapeutic efficacy and cytotoxicity of drugs.

Enhancement of endothelial function and attenuation of portal vein injury using mesenchymal stem cells carrying miRNA-25-3p

The aims of this study were to determine whether human umbilical cord mesenchymal stem cells (hucMSCs) modified by miRNA-25-3p (miR-25-3p) overexpression could promote venous endothelial cell proliferation and attenuate portal endothelial cell injury. HucMSCs and human umbilical vein endothelial cells (HUVEC) were isolated and cultured from human umbilical cord and characterized. Lentiviral vectors expressing miRNA-25-3p were transfected into hucMSCs and confirmed by PCR. We verified the effect of miR-25-3p-modified hucMSCs on HUVEC by cell co-culture and cell supernatant experiments. Subsequently, exosomes of miR-25-3p-modified hucMSCs were isolated from cell culture supernatants and characterized by WB, NTA and TEM. We verified the effects of miR-25-3p-modified exosomes derived from hucMSCs on HUVEC proliferation, migration, and angiogenesis by in vitro cellular function experiments. Meanwhile, we further examined the downstream target genes and signaling pathways potentially affected by miR-25-3p-modified hucMSC-derived exosomes in HUVEC. Finally, we established a rat portal vein venous thrombosis model by injecting CM-DiR-labeled hucMSCs intravenously into rats and examining the homing of cells in the portal vein by fluorescence microscopy. Histological and immunohistochemical experiments were used to examine the effects of miRNA-25-3p-modified hucMSCs on the proliferation and damage of portal vein endothelial cells. Primary hucMSCs and HUVECs were successfully isolated, cultured and characterized. Primary hucMSCs were modified with a lentiviral vector carrying miR-25-3p at MOI 80. Co-culture and cell supernatant intervention experiments showed that overexpression of miRNA-25-3p in hucMSCs enhanced HUVEC proliferation, migration and tube formation in vitro. We successfully isolated and characterized exosomes of miR-25-3p-modified hucMSCs, and exosome intervention experiments demonstrated that miR-25-3p-modified exosomes derived from hucMSCs similarly enhanced the proliferation, migration, and angiogenesis of HUVECs. Subsequent PCR and WB analyses indicated PTEN/KLF4/AKT/ERK1/2 as potential pathways of action. Analysis in a rat portal vein thrombosis model showed that miR-25-3p-modified hucMSCs could homing to damaged portal veins. Subsequent histological and immunohistochemical examinations demonstrated that intervention with miR-25-3p overexpression-modified hucMSCs significantly reduced damage and attenuated thrombosis in rat portal veins. The above findings indicate suggest that hucMSCs based on miR-25-3p modification may be a promising therapeutic approach for use in venous thrombotic diseases.

Bibliometric and visualized analysis of the applications of exosomes based drug delivery

Exosomes, endogenous vesicles secreted by cells, possess unique properties like high biocompatibility, low immunogenicity, targeting ability, long half-life, and blood-brain barrier permeability. They serve as crucial intercellular communication vectors in physiological processes and disease occurrence. Our comprehensive analysis of exosome-based drug delivery research from 2013 to 2023 revealed 2,476 authors from 717 institutions across 33 countries. Keyword clustering identified five research areas: drug delivery, mesenchymal stem cells, cancer immunotherapy, targeting ligands, surface modifications, and macrophages. The combination of exosome drug delivery technology with a proven clinical model enables the precise targeting of tumors with chemotherapy or radiosensitising agents, as well as facilitating gene therapy. This bibliometric analysis aims to characterize the current state and advance the clinical application of exosome-based drug delivery systems.

An Overview on the Physiopathology of the Blood-Brain Barrier and the Lipid-Based Nanocarriers for Central Nervous System Delivery

The state of well-being and health of our body is regulated by the fine osmotic and biochemical balance established between the cells of the different tissues, organs, and systems. Specific districts of the human body are defined, kept in the correct state of functioning, and, therefore, protected from exogenous or endogenous insults of both mechanical, physical, and biological nature by the presence of different barrier systems. In addition to the placental barrier, which even acts as a linker between two different organisms, the mother and the fetus, all human body barriers, including the blood-brain barrier (BBB), blood-retinal barrier, blood-nerve barrier, blood-lymph barrier, and blood-cerebrospinal fluid barrier, operate to maintain the physiological homeostasis within tissues and organs. From a pharmaceutical point of view, the most challenging is undoubtedly the BBB, since its presence notably complicates the treatment of brain disorders. BBB action can impair the delivery of chemical drugs and biopharmaceuticals into the brain, reducing their therapeutic efficacy and/or increasing their unwanted bioaccumulation in the surrounding healthy tissues. Recent nanotechnological innovation provides advanced biomaterials and ad hoc customized engineering and functionalization methods able to assist in brain-targeted drug delivery. In this context, lipid nanocarriers, including both synthetic (liposomes, solid lipid nanoparticles, nanoemulsions, nanostructured lipid carriers, niosomes, proniosomes, and cubosomes) and cell-derived ones (extracellular vesicles and cell membrane-derived nanocarriers), are considered one of the most successful brain delivery systems due to their reasonable biocompatibility and ability to cross the BBB. This review aims to provide a complete and up-to-date point of view on the efficacy of the most varied lipid carriers, whether FDA-approved, involved in clinical trials, or used in in vitro or in vivo studies, for the treatment of inflammatory, cancerous, or infectious brain diseases.

Utilizing network pharmacology, molecular docking, and animal models to explore the therapeutic potential of the WenYang FuYuan recipe for cerebral ischemia-reperfusion injury through AGE-RAGE and NF-κB/p38MAPK signaling pathway modulation

BACKGROUND

Stroke is a debilitating condition with high morbidity, disability, and mortality that significantly affects the quality of life of patients. In China, the WenYang FuYuan recipe is widely used to treat ischemic stroke. However, the underlying mechanism remains unknown, so exploring the potential mechanism of action of this formula is of great practical significance for stroke treatment.

OBJECTIVE

This study employed network pharmacology, molecular docking, and in vivo experiments to clarify the active ingredients, potential targets, and molecular mechanisms of the WenYang FuYuan recipe in cerebral ischemia-reperfusion injury, with a view to providing a solid scientific foundation for the subsequent study of this recipe.

MATERIALS AND METHODS

Active ingredients of the WenYang FuYuan recipe were screened using the traditional Chinese medicine systems pharmacology database and analysis platform. Network pharmacology approaches were used to explore the potential targets and mechanisms of action of the WenYang FuYuan recipe for the treatment of cerebral ischemia-reperfusion injury. The Middle Cerebral Artery Occlusion/Reperfusion 2 h Sprague Dawley rat model was prepared, and TTC staining and modified neurological severity score were applied to examine the neurological deficits in rats. HE staining and Nissl staining were applied to examine the pathological changes in rats. Immunofluorescence labeling and Elisa assay were applied to examine the expression levels of certain proteins and associated factors, while qRT-PCR and Western blotting were applied to examine the expression levels of linked proteins and mRNAs in disease-related signaling pathways.

RESULTS

We identified 62 key active ingredients in the WenYang FuYuan recipe, with 222 highly significant I/R targets, forming 138 pairs of medication components and component-targets, with the top five being Quercetin, Kaempferol, Luteolin, β-sitosterol, and Stigmasterol. The key targets included TP53, RELA, TNF, STAT1, and MAPK14 (p38MAPK). Targets related to cerebral ischemia-reperfusion injury were enriched in chemical responses, enzyme binding, endomembrane system, while enriched pathways included lipid and atherosclerosis, fluid shear stress and atherosclerosis, AGE-RAGE signaling in diabetic complications. In addition, the main five active ingredients and targets in the WenYang FuYuan recipe showed high binding affinity (e.g. Stigmasterol and MAPK14, total energy <-10.5 Kcal/mol). In animal experiments, the WenYang FuYuan recipe reduced brain tissue damage, increased the number of surviving neurons, and down-regulated S100β and RAGE protein expression. Moreover, the relative expression levels of key targets such as TP53, RELA and p38MAPK mRNA were significantly down-regulated in the WenYang FuYuan recipe group, and serum IL-6 and TNF-a factor levels were reduced. After WenYang FuYuan recipe treatment, the AGE-RAGE signaling pathway and downstream NF-kB/p38MAPK signaling pathway-related proteins were significantly modulated.

CONCLUSION

This study utilized network pharmacology, molecular docking, and animal experiments to identify the potential mechanism of the WenYang FuYuan recipe, which may be associated with the regulation of the AGE-RAGE signaling pathway and the inhibition of target proteins and mRNAs in the downstream NF-kB/p38MAPK pathway.

Exosomes derived from HUVECs alleviate ischemia-reperfusion induced inflammation in neural cells by upregulating KLF14 expression

Neuroinflammation plays a key role in the progression of secondary brain injury after ischemic stroke, and exosomes have been increasingly recognized to eliminate inflammatory responses through various mechanisms. This study aimed to explore the effect and possible mechanism of human umbilical vein endothelial cells derived exosomes (H-EXOs) on neuroinflammation. We established a transient middle cerebral artery occlusion/reperfusion (tMCAO/R) in male rats and oxygen-glucose-deprivation/reoxygenation (OGD/R) model in cultured neurons to mimic secondary brain injury after ischemic stroke in vivo. H-EXOs were administered at the same time of reperfusion. Results showed that the production of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6, and the transcription factor Krüppel-like factor 14 (KLF14) were significantly increased both in rat brain tissue and cultured neural cells after ischemic-reperfusion (I/R) injury. H-EXOs treatment significantly improved the cultured cell viability, reduced infarct sizes, mitigated neurobehavioral defects, and alleviated the expression of pro-inflammatory cytokines compared with the control group, indicating that H-EXOs exerted anti-inflammatory effect against I/R injury. Further studies revealed that the anti-inflammatory effect of H-EXOs could be weakened by small-interfering RNA (siKLF4) transfection. KLF14 was a protective factor produced during cerebral ischemia-reperfusion injury. In conclusion, H-EXOs protect neurons from inflammation after I/R injury by enhancing KLF14 expression.

Delivery-mediated exosomal therapeutics in ischemia-reperfusion injury: advances, mechanisms, and future directions

Ischemia-reperfusion injury (IRI) poses significant challenges across various organ systems, including the heart, brain, and kidneys. Exosomes have shown great potentials and applications in mitigating IRI-induced cell and tissue damage through modulating inflammatory responses, enhancing angiogenesis, and promoting tissue repair. Despite these advances, a more systematic understanding of exosomes from different sources and their biotransport is critical for optimizing therapeutic efficacy and accelerating the clinical adoption of exosomes for IRI therapies. Therefore, this review article overviews the administration routes of exosomes from different sources, such as mesenchymal stem cells and other somatic cells, in the context of IRI treatment. Furthermore, this article covers how the delivered exosomes modulate molecular pathways of recipient cells, aiding in the prevention of cell death and the promotions of regeneration in IRI models. In the end, this article discusses the ongoing research efforts and propose future research directions of exosome-based therapies.

Therapeutic efficacy and pharmacological mechanism of Yindan Xinnaotong soft capsule on acute ischemic stroke: a meta-analysis and network pharmacology analysis

Yindan Xinnaotong soft capsule (YDXNT), a traditional Chinese medicine preparation, has shown a promising effect in the treatment of acute ischemic stroke (AIS). The goal of this study was to investigate the therapeutic effects and pharmacological mechanisms of YDXNT on AIS. Randomized controlled trials were searched and screened. Review Manager 5.4 was used for a meta-analysis. Active ingredients and targets of YDXNT were extracted from the Traditional Chinese Medicine Systems Pharmacology Database, Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine, and Encyclopaedia of Traditional Chinese Medicine. AIS-related targets were retrieved from GeneCards, OMIM, and DrugBank databases. We constructed PPI and ingredient-target networks, performed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses, and conducted molecular docking. The YDXNT group had a higher total effective rate and a higher Barthel Index score. YDXNT reduced the low-density lipoprotein cholesterol and the whole blood viscosity at high and shear rates. Our study identified 313 ingredients and 1196 common targets. The key ingredients were mainly quercetin, neocryptotanshinone II, miltionone I, neotanshinone C, and tanshiquinone B, and the key targets were mainly SRC, MAPK3, AKT1, MAPK1, and JUN. GO analysis showed that the core targets mainly involved in atherosclerosis and neural apoptosis. The core pathways were lipid and atherosclerosis, PI3K-Akt, MAPK, and other pathways. Key ingredients exhibited robust binding interactions with core targets. YDXNT could effectively improve the total effective rate, ability of daily life, blood lipids, and blood viscosity. Antiatherosclerotic and neuroprotective effects are the main pharmacological mechanisms.Registration number: CRD42023400127.

A vivid outline demonstrating the benefits of exosome-mediated drug delivery in CNS-associated disease environments

The efficacy of drug delivery mechanisms has been improvised with time for different therapeutic purposes. In most cases, nano-sized delivery systems have been modeled over decades for the on-target applicability of the drugs. The use of synthetic drug delivery materials has been a common practice, although research has now focussed more on using natural vehicles, to avoid the side effects of synthetic delivery systems and easy acceptance by the body. Exosome is such a natural nano-sized vehicle that exceeds the efficiency of many natural vehicles, for being immune-friendly, due to its origin. Unlike, other natural drug delivery systems, exosomes are originated within the body's cells, and from there, they happen to travel through the extracellular matrices into neighboring cells. This capacity of exosomes has made them an efficient drug delivery system over recent years and now a large number of researches have been carried out to develop exosomes as natural drug delivery vehicles. Several experimental strategies have been practiced in this regard which have shown that exosomes are exclusively capable of carrying drugs and they can also be used in targeted delivery, for which they efficiently can reach and release the drug at their target cells for consecutive effects. One of the most interesting features of exosomes is they can cross the blood-brain barrier (BBB) in the body and hence, for the disease where other delivery vehicles are incapable of reaching the destination of the drug, exosomes can overcome the hurdle. This review particularly, focuses on the different aspects of using exosomes as a potential nano-sized drug delivery system for some of the severe diseases associated with the central nervous system of the human body.

Novel insight into the therapeutical potential of flavonoids from traditional Chinese medicine against cerebral ischemia/reperfusion injury

Cerebral ischemia/reperfusion injury (CIRI) is a major contributor to poor prognosis of ischemic stroke. Flavonoids are a broad family of plant polyphenols which are abundant in traditional Chinese medicine (TCM) and have beneficial effects on several diseases including ischemic stroke. Accumulating studies have indicated that flavonoids derived from herbal TCM are effective in alleviating CIRI after ischemic stroke in vitro or in vivo, and exhibit favourable therapeutical potential. Herein, we systematically review the classification, metabolic absorption, neuroprotective efficacy, and mechanisms of TCM flavonoids against CIRI. The literature suggest that flavonoids exert potential medicinal functions including suppressing excitotoxicity, Ca2+ overloading, oxidative stress, inflammation, thrombin's cellular toxicity, different types of programmed cell deaths, and protecting the blood-brain barrier, as well as promoting neurogenesis in the recovery stage following ischemic stroke. Furthermore, we identified certain matters that should be taken into account in future research, as well as proposed difficulties and opportunities in transforming TCM-derived flavonoids into medications or functional foods for the treatment or prevention of CIRI. Overall, in this review we aim to provide novel ideas for the identification of new prospective medication candidates for the therapeutic strategy against ischemic stroke.

Quercetin, a Flavonoid with Great Pharmacological Capacity

Quercetin is a flavonoid with a low molecular weight that belongs to the human diet's phenolic phytochemicals and nonenergy constituents. Quercetin has a potent antioxidant capacity, being able to capture reactive oxygen species (ROS), reactive nitrogen species (RNS), and reactive chlorine species (ROC), which act as reducing agents by chelating transition-metal ions. Its structure has five functional hydroxyl groups, which work as electron donors and are responsible for capturing free radicals. In addition to its antioxidant capacity, different pharmacological properties of quercetin have been described, such as carcinostatic properties; antiviral, antihypertensive, and anti-inflammatory properties; the ability to protect low-density lipoprotein (LDL) oxidation, and the ability to inhibit angiogenesis; these are developed in this review.

Exosomes: A Cellular Communication Medium That Has Multiple Effects On Brain Diseases

Exosomes, as membranous vesicles generated by multiple cell types and secreted to extracellular space, play a crucial role in a range of brain injury-related brain disorders by transporting diverse proteins, RNA, DNA fragments, and other functional substances. The nervous system's pathogenic mechanisms are complicated, involving pathological processes like as inflammation, apoptosis, oxidative stress, and autophagy, all of which result in blood-brain barrier damage, cognitive impairment, and even loss of normal motor function. Exosomes have been linked to the incidence and progression of brain disorders in recent research. As a result, a thorough knowledge of the interaction between exosomes and brain diseases may lead to the development of more effective therapeutic techniques that may be implemented in the clinic. The potential role of exosomes in brain diseases and the crosstalk between exosomes and other pathogenic processes were discussed in this paper. Simultaneously, we noted the delicate events in which exosomes as a media allow the brain to communicate with other tissues and organs in physiology and disease, and compiled a list of natural compounds that modulate exosomes, in order to further improve our understanding of exosomes and propose new ideas for treating brain disorders.

Exosomes-Mediated Signaling Pathway: A New Direction for Treatment of Organ Ischemia-Reperfusion Injury

Ischemia reperfusion (I/R) is a common pathological process which occurs mostly in organs like the heart, brain, kidney, and lung. The injury caused by I/R gradually becomes one of the main causes of fatal diseases, which is an urgent clinical problem to be solved. Although great progress has been made in therapeutic methods, including surgical, drug, gene therapy, and transplant therapy for I/R injury, the development of effective methods to cure the injury remains a worldwide challenge. In recent years, exosomes have attracted much attention for their important roles in immune response, antigen presentation, cell migration, cell differentiation, and tumor invasion. Meanwhile, exosomes have been shown to have great potential in the treatment of I/R injury in organs. The study of the exosome-mediated signaling pathway can not only help to reveal the mechanism behind exosomes promoting reperfusion injury recovery, but also provide a theoretical basis for the clinical application of exosomes. Here, we review the research progress in utilizing various exosomes from different cell types to promote the healing of I/R injury, focusing on the classical signaling pathways such as PI3K/Akt, NF-κB, Nrf2, PTEN, Wnt, MAPK, toll-like receptor, and AMPK. The results suggest that exosomes regulate these signaling pathways to reduce oxidative stress, regulate immune responses, decrease the expression of inflammatory cytokines, and promote tissue repair, making exosomes a competitive emerging vector for treating I/R damage in organs.

The Landscape of Biomimetic Nanovesicles in Brain Diseases

Brain diseases, such as brain tumors, neurodegenerative diseases, cerebrovascular diseases, and brain injuries, are caused by various pathophysiological changes, which pose a serious health threat. Brain disorders are often difficult to treat due to the presence of the blood-brain barrier (BBB). Biomimetic nanovesicles (BNVs), including endogenous extracellular vesicles (EVs) derived from various cells and artificial nanovesicles, possess the ability to penetrate the BBB and thus can be utilized for drug delivery to the brain. BNVs, especially endogenous EVs, are widely distributed in body fluids and usually carry various disease-related signal molecules such as proteins, RNA, and DNA, and may also be analyzed to understand the etiology and pathogenesis of brain diseases. This review covers the exhaustive classification and characterization of BNVs and pathophysiological roles involved in various brain diseases, and emphatically focuses on nanotechnology-integrated BNVs for brain disease theranostics, including various diagnosis strategies and precise therapeutic regulations (e.g., immunity regulation, disordered protein clearance, anti-neuroinflammation, neuroregeneration, angiogenesis, and the gut-brain axis regulation). The remaining challenges and future perspectives regarding the nanotechnology-integrated BNVs for the diagnosis and treatment of brain diseases are also discussed and outlined.

Exosome-delivered miR-410-3p reverses epithelial-mesenchymal transition, migration and invasion of trophoblasts in spontaneous abortion

Current studies have indicated that insufficient trophoblast epithelial-mesenchymal transition (EMT), migration and invasion are crucial for spontaneous abortion (SA) occurrence and development. Exosomal miRNAs play significant roles in embryonic development and cellular communication. Hereon, we explored the roles of serum exosomes derived from SA patients on trophoblast EMT, migration and invasion. Exosomes were isolated from normal control (NC) patients with abortion for unplanned pregnancy and SA patients, then characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and western blotting. Exosomal miRNA profiles were identified by miRNA sequencing. The effects of serum exosomes on trophoblast migration and invasion were detected by scratch wound healing and transwell assays, and other potential mechanisms were revealed by quantitative real-time PCR (RT-PCR), western blotting and dual-luciferase reporter assay. Finally, animal experiments were used to explore the effects of exosomal miR-410-3p on embryo absorption in mice. The serum exosomes from SA patients inhibited trophoblast EMT and reduced their migration and invasion ability in vitro. The miRNA sequencing showed that miR-410-3p was upregulated in SA serum exosomes. The functional experiments showed that SA serum exosomes restrained trophoblast EMT, migration and invasion by releasing miR-410-3p. Mechanistically, SA serum exosomal miR-410-3p inhibited trophoblast cell EMT, migration and invasion by targeting TNF receptor-associated factor 6 (TRAF6) at the post-transcriptional level. Besides, SA serum exosomal miR-410-3p inhibited the p38 MAPK signalling pathway by targeting TRAF6 in trophoblasts. Moreover, milk exosomes loaded with miR-410-3p mimic reached the maternal-fetal interface and aggravated embryo absorption in female mice. Clinically, miR-410-3p and TRAF6 expression were abnormal and negatively correlated in the placental villi of SA patients. Our findings indicated that exosome-derived miR-410-3p plays an important role between SA serum and trophoblasts in intercellular communication, suggesting a novel mechanism by which serum exosomal miRNA regulates trophoblasts in SA patients.

Current progression in application of extracellular vesicles in central nervous system diseases

Early diagnosis and pharmacological treatment of central nervous system (CNS) diseases has been a long-standing challenge for clinical research due to the presence of the blood-brain barrier. Specific proteins and RNAs in brain-derived extracellular vesicles (EVs) usually reflect the corresponding state of brain disease, and therefore, EVs can be used as diagnostic biomarkers for CNS diseases. In addition, EVs can be engineered and fused to target cells for delivery of cargo, demonstrating the great potential of EVs as a nanocarrier platform. We review the progress of EVs as markers and drug carriers in the diagnosis and treatment of neurological diseases. The main areas include visual imaging, biomarker diagnosis and drug loading therapy for different types of CNS diseases. It is hoped that increased knowledge of EVs will facilitate their clinical translation in CNS diseases.

Engineered exosomes derived from stem cells: a new brain-targeted strategy

INTRODUCTION

Using engineered exosomes produced from stem cells is an experimental therapeutic approach for treating brain diseases. According to reports, preclinical research has demonstrated notable neurogenesis and angiogenesis effects using modified stem cell-derived exosomes. These biological nanoparticles have a variety of anti-apoptotic, anti-inflammatory, and antioxidant properties that make them very promising for treating nervous system disorders.

AREAS COVERED

This review examines different ways to enhance the delivery of modified stem cell-derived exosomes, how they infiltrate the blood-brain barrier (BBB), and how they facilitate their access to the brain. We would also like to determine whether these nanoparticles have the most significant transmission rates through BBB when targeting brain lesions.

EXPERT OPINION

Using engineered stem cell-derived exosomes for treating brain disorders has generated considerable attention toward clinical research and application. However, stem cell-derived exosomes lack consistency, and their mechanisms of action are uncertain. Therefore, upcoming research needs to prioritize examining the underlying mechanisms and strategies via which these nanoparticles combat neurological disorders.

Neural stem cell-derived exosomes-loaded adhesive hydrogel controlled-release promotes cerebral angiogenesis and neurological function in ischemic stroke

OBJECTIVE

Ischemic stroke has become one of the leading diseases for international death, which brings burden to the economy and society. Exosomes (Exos) derived following neural stem cells (NSCs) stimulation promote neurogenesis and migration of NSCs. However, Exos themselves are easily to be removed in vivo. Our study is to investigate whether adhesive hyaluronic acid (HAD) hydrogel loading NSCs-derived-Exo (HAD-Exo) would promote the recovery of ischemic stroke.

METHODS

A mouse model of middle cerebral artery occlusion (MCAO) was established. PBS, Exo, HAD, and HAD-Exo groups were independently stereotactically injected in mice, respectively. The modified neurological severity score scale and behaviour tests were used to evaluate neurological improvement. Neuroimagings were used to observe the improvement of cerebral infarct volume and vessels. Immunofluorescence staining was used to verify the expression of vascular and cell proliferation-related proteins.

RESULTS

The structural and mechanical property of HAD and HAD-Exo were detected. Behavioral results showed that HAD-Exo significantly improved neurological functions, especially motor function. Neuroimagings showed that HAD-Exo significantly promoted infarct volume and angiogenesis. Immunofluorescence staining showed that HAD-Exo significantly promoted the cerebral angiogenesis and anti-inflammation.

CONCLUSION

NSCs derived exosomes-loaded adhesive HAD hydrogel controlled-release could promote cerebral angiogenesis and neurological function for ischemic stroke.

Mesenchymal stem cell-derived exosomes: Shaping the next era of stroke treatment

Exosome-based treatments are gaining traction as a viable approach to addressing the various issues faced by an ischemic stroke. These extracellular vesicles, mainly produced by Mesenchymal Stem Cells (MSCs), exhibit many properties with substantial therapeutic potential. Exosomes are particularly appealing for stroke therapy because of their low immunogenicity, effective cargo transport, and ability to cross the blood-brain barrier. Their diverse effects include neuroprotection, angiogenesis stimulation, inflammatory response modulation, and cell death pathway attenuation, synergistically promoting neuronal survival, tissue regeneration, and functional recovery. Exosomes also show potential as diagnostic indicators for early stroke identification and customized treatment options. Despite these promising qualities, current exosome-based therapeutics have some limitations. The heterogeneity of exosome release among cell types, difficulty in standardization and isolation techniques, and complications linked to dosage and targeted administration necessitates extensive investigation. It is critical to thoroughly understand exosomal processes and their complicated interactions within the cellular milieu. To improve the practicality and efficacy of exosome-based medicines, research efforts must focus on improving production processes, developing robust evaluation criteria, and developing large-scale isolation techniques. Altogether, exosomes' multifunctional properties offer a new route for transforming stroke treatment and significantly improving patient outcomes.

Targeting Nrf2 signaling pathway by quercetin in the prevention and treatment of neurological disorders: An overview and update on new developments

BACKGROUND

Neurological disorders (NLDs) are widely acknowledged as a significant public health concern worldwide. Stroke, Alzheimer's disease (AD), and traumatic brain injury (TBI) are three of these disorders that have sparked major study attention. Neurological dysfunction, protein buildup, oxidation and neuronal injury, and aberrant mitochondria are all prevalent neuropathological hallmarks of these disorders. The signaling cascade of nuclear factor erythroid 2 related factor 2 (Nrf2) shares all of them as a common target. Several studies have found that overexpression of Nrf2 is a promising treatment method in NLDs. Effective treatment of these disorders continues to be a universal concern regardless of various medicines. In order to treat a variety of neurological problems, organic remedies may provide an alternative treatment. It has been demonstrated that polyphenols like quercetin (Que) offer considerable capabilities for treating NLDs. One of Que's greatest key targets, Nrf2, has the capacity to control the production of a number of cytoprotective enzymes that exhibit neuroprotective, detoxifying, and antioxidative effects. Additionally, Que enhanced the expression of Nrf2 and inhibited alterations in the shape and death of neurons in the hippocampus.

OBJECTIVE

In this review, we have focused on Que's medicinal prospects as a neuroprotective drug.

METHODS

PubMed, Scopus, Science Direct, and Google Scholar were used to search articles for this study.

RESULTS

The findings of this research demonstrate that (1) Que protected the blood-brain barrier via stimulating Nrf2 in animal stroke, which alleviated ischemic reperfusion and motor dysfunction. (2) By triggering the Nrf2 pathway, Que reduced the neuroinflammation and oxidative damage brought on by TBI in the cortex. (3) In an experimental model of AD, Que enhanced cognitive function by decreasing A1-4, antioxidant activity, and Nrf2 levels in the brain.

CONCLUSION

We discuss recent research on Que-mediated Nrf2 expression in the management of several NLDs in this paper.

Neuroprotective effects of oxytocin against ischemic stroke in rats by blocking glutamate release and CREB-mediated DNA hypermethylation

Glutamate plays a crucial role in cognitive impairments after ischemic stroke. There is a scarcity of information about how glutamate-induced activation of cAMP-response element binding (CREB) signaling pathway regulates both the negative and positive regulators of synaptic plasticity. Recent studies have demonstrated the involvement of prominent epigenetic repressors, such as MeCP2 and DNMTs, in stroke. Neuroprotective effects of oxytocin against ischemia have been previously reported, while the underlying mechanism is still elusive. In this research, the possible role of CREB-mediated DNA hypermethylation and the potential mechanism of oxytocin in a rat model of permanent middle cerebral artery occlusion (pMCAO) were assessed. Adult male Sprague-Dawley rats were pretreated with intraperitoneal injection of oxytocin at the onset of pMCAO. The effects of oxytocin on spines and the expression levels of synaptic genes were determined. The regulatory effects of oxytocin on glutamate level, N-methyl-D-aspartate receptors (NMDARs), its downstream CREB pathway, and global or gene-specific DNA methylation status were evaluated by immunofluorescence, co-immunoprecipitation, and chromatin immunoprecipitation, respectively. We found that CREB could act as a common transcription factor for MeCP2 and DNMT3B after ischemic stroke. Oxytocin dose-dependently deactivated NR2B-related CaM-CREB pathway and inhibited DNA hypermethylation at the CpG islands of Ngf gene in pMCAO-operated rats. Moreover, oxytocin prevented pMCAO-induced reduction in the number of spines and neural cells. DNA hypermethylation in Ngf gene contributed to the cognitive deficits post-stroke. The neuroprotective effects of oxytocin against ischemia could be attributed to inhibiting glutamate release, providing additional evidence on the mechanism of oxytocin against ischemic stroke.

Optimization of exosome-based cell-free strategies to enhance endogenous cell functions in tissue regeneration

Exosomes, nanoscale extracellular vesicles, play a crucial role in intercellular communication, owing to their biologically active cargoes such as RNAs and proteins. In recent years, they have emerged as a promising tool in the field of tissue regeneration, with the potential to initiate a new trend in cell-free therapy. However, it's worth noting that not all types of exosomes derived from cells are appropriate for tissue repair. Thus, selecting suitable cell sources is critical to ensure their efficacy in specific tissue regeneration processes. Current therapeutic applications of exosomes also encounter several limitations, including low-specific content for targeted diseases, non-tissue-specific targeting, and short retention time due to rapid clearance in vivo. Consequently, this review paper focuses on exosomes from diverse cell sources with functions specific to tissue regeneration. It also highlights the latest engineering strategies developed to overcome the functional limitations of natural exosomes. These strategies encompass the loading of specific therapeutic contents into exosomes, the endowment of tissue-specific targeting capability on the exosome surface, and the incorporation of biomaterials to extend the in vivo retention time of exosomes in a controlled-release manner. Collectively, these innovative approaches aim to synergistically enhance the therapeutic effects of natural exosomes, optimizing exosome-based cell-free strategies to boost endogenous cell functions in tissue regeneration. STATEMENT OF SIGNIFICANCE: Exosome-based cell-free therapy has recently emerged as a promising tool for tissue regeneration. This review highlights the characteristics and functions of exosomes from different sources that can facilitate tissue repair and their contributions to the regeneration process. To address the functional limitations of natural exosomes in therapeutic applications, this review provides an in-depth understanding of the latest engineering strategies. These strategies include optimizing exosomal contents, endowing tissue-specific targeting capability on the exosome surface, and incorporating biomaterials to extend the in vivo retention time of exosomes in a controlled-release manner. This review aims to explore and discuss innovative approaches that can synergistically improve endogenous cell functions in advanced exosome-based cell-free therapies for a broad range of tissue regeneration.

FUS-mediated HypEVs: Neuroprotective effects against ischemic stroke

Few studies have investigated the properties and protein composition of small extracellular vesicles (sEVs) derived from neurons under hypoxic conditions. Presently, the extent of the involvement of these plentiful sEVs in the onset and progression of ischemic stroke remains an unresolved question. Our study systematically identified the characteristics of sEVs derived from neurons under hypoxic conditions (HypEVs) by physical characterization, sEV absorption, proteomics and transcriptomics analysis. The effects of HypEVs on neurites, cell survival, and neuron structure were assessed in vitro and in vivo by neural complexity tests, magnetic resonance imaging (MRI), Golgi staining, and Western blotting of synaptic plasticity-related proteins and apoptotic proteins. Knockdown of Fused in Sarcoma (FUS) small interfering RNA (siRNA) was used to validate FUS-mediated HypEV neuroprotection and mitochondrial mRNA release. Hypoxia promoted the secretion of sEVs, and HypEVs were more easily taken up and utilized by recipient cells. The MRI results illustrated that the cerebral infarction volume was reduced by 45% with the application of HypEVs, in comparison to the non- HypEV treatment group. Mechanistically, the FUS protein is necessary for the uptake and neuroprotection of HypEVs against ischemic stroke as well as carrying a large amount of mitochondrial mRNA in HypEVs. However, FUS knockdown attenuated the neuroprotective rescue capabilities of HypEVs. Our comprehensive dataset clearly illustrates that FUS-mediated HypEVs deliver exceptional neuroprotective effects against ischemic stroke, primarily through the maintenance of neurite integrity and the reduction of mitochondria-associated apoptosis.

Bio-clickable, small extracellular vesicles-COCKTAIL therapy for ischemic stroke

Delivering large therapeutic molecules via the blood-brain barrier to treat ischemic stroke remains challenging. NR2B9c is a potent neuroprotective peptide but it's safe and targeted delivery to the brain requires an efficient, natural, and non-immunogenic delivery technique. Small extracellular vesicles (sEVs) have shown great potential as a non-immunogenic, natural cargo delivery system; however, tailoring of its inefficient brain targeting is desired. Here, we coupled rabies virus glycoprotein 29 with sEVs surface via bio-orthogonal click chemistry reactions, followed by loading of NR2B9c, ultimately generating stroke-specific therapeutic COCKTAIL (sEVs-COCKTAIL). Primary neurons and Neuro-2a cells were cultured for in vitro and transient middle cerebral artery occlusion model was used for in vivo studies to evaluate neuron targeting and anti-ischemic stroke potential of the sEVs-COCKTAIL. Bio-clickable sEVs were selectively taken up by neurons but not glial cells. In the in vitro ischemic stroke model of oxygen-glucose deprivation, the sEVs-COCKTAIL exhibited remarkable potential against reactive oxygen species and cellular apoptosis. In vivo studies further demonstrated the brain targeting and increased half-life of bio-clickable sEVs, delivering NR2B9c to the ischemic brain and reducing stroke injury. Treatment with the sEVs-COCKTAIL significantly increased behavioral recovery and reduced neuronal apoptosis after transient middle cerebral artery occlusion. NR2B9c was delivered to neurons binding to post-synaptic density protein-95, inhibiting N-methyl-d-Aspartate receptor-mediated over production of oxidative stress and mitigating protein B-cell lymphoma 2 and P38 proteins expression. Our results provide an efficient and biocompatible approach to a targeted delivery system, which is a promising modality for stroke therapy.

Engineered extracellular vesicles for ischemic stroke: a systematic review and meta-analysis of preclinical studies

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the efficacy of engineered extracellular vesicles (EEVs) in the treatment of ischemic stroke (IS) in preclinical studies and to compare them with natural extracellular vesicles (EVs). The systematic review provides an up-to-date overview of the current state of the literature on the use of EEVs for IS and informs future research in this area.

METHODS

We searched PubMed, EMBASE, Web of Science, Cochrane Library, and Scopus databases for peer-reviewed preclinical studies on the therapeutic effect of EEVs on IS.Databases ranged from the inception to August 1, 2023. The outcome measures included infarct volumes, neurological scores, behavioral scores, apoptosis rates, numbers of neurons, and levels of IL-1β, IL-6, and TNF-α. The CAMARADES checklist was used to assess the quality and bias risks of the studies. All statistical analyses were performed using RevMan 5.4 software.

RESULTS

A total of 28 studies involving 1760 animals met the inclusion criteria. The results of the meta-analysis showed that compared to natural EVs, EEVs reduced infarct volume (percentage: SMD = -2.33, 95% CI: -2.92, -1.73; size: SMD = -2.36, 95% CI: -4.09, -0.63), improved neurological scores (mNSS: SMD = -1.78, 95% CI: -2.39, -1.17; Zea Longa: SMD = -2.75, 95% CI: -3.79, -1.71), promoted behavioral recovery (rotarod test: SMD = 2.50, 95% CI: 1.81, 3.18; grid-walking test: SMD = -3.45, 95% CI: -5.15, -1.75; adhesive removal test: SMD = -2.60, 95% CI: -4.27, -0.93; morris water maze test: SMD = -3.91, 95% CI: -7.03, -0.79), and reduced the release of proinflammatory factors (IL-1β: SMD = -2.02, 95% CI: -2.77, -1.27; IL-6: SMD = -3.01, 95% CI: -4.47, -1.55; TNF-α: SMD = -2.72, 95% CI: -4.30, -1.13), increasing the number of neurons (apoptosis rate: SMD = -2.24, 95% CI: -3.32, -1.16; the number of neurons: SMD = 3.70, 95% CI: 2.44, 4.96). The funnel plots for the two main outcome measures were asymmetric, indicating publication bias. The median score on the CAMARADES checklist was 7 points (IQR: 6-9).

CONCLUSIONS

This meta-analysis shows that EEVs are superior to natural EVs for the treatment of IS. However, research in this field is still at an early stage, and more research is needed to fully understand the potential therapeutic mechanism of EEVs and their potential use in the treatment of IS.

PROSPERO REGISTRATION NUMBER

CRD42022368744.

The effect of AQP4 on tau protein aggregation in neurodegeneration and persistent neuroinflammation after cerebral microinfarcts

This study aimed to investigate the effect of aquaporin-4 (AQP4) on tau protein aggregation in neurodegeneration and persistent neuroinflammation after cerebral microinfarcts. A model of diffuse ischemic brain injury was established, and adenovirus was injected stereotactically through the lateral ventricle of mice. The water content of the brain tissue was measured. The co-expression of glial fibrillary acidic protein (GFAP) and AQP4 and the aggregation of p-tau and neuronal marker were detected through immunofluorescence double staining. The expression of phosphorylated microtubule-associated protein tau (p-tau, Ser202/Thr205, Thr205, Ser396, Ser404), interleukin(IL)-6, IL-1β, tumor necrosis factor (TNF)-a, growth associated protein43 (GAP43), GFAP, and ionized calcium-binding adapter molecule 1 (Iba1) was detected through Western blot. It was found that the brain water content in the model group was increased and decreased after the AQP4 interference. Compared with the sham group, the expression of GFAP, p-tau, IL-1β, TNF-a, Iba1, and p-tau was increased in the model group (p < 0.05). Compared with the model group, the expression of p-tau, IL-6, IL-1β, TNF-a, GFAP, and Iba1 was decreased after AQP4 interference (p < 0.05). It is indicated that AQP4 positively regulates neurodegeneration and persistent neuroinflammation caused by tau protein aggregation after cerebral microinfarcts.

Recent advances in lipid nanovesicles for targeted treatment of spinal cord injury

The effective regeneration and functional restoration of damaged spinal cord tissue have been a long-standing concern in regenerative medicine. Treatment of spinal cord injury (SCI) is challenging due to the obstruction of the blood-spinal cord barrier (BSCB), the lack of targeting of drugs, and the complex pathophysiology of injury sites. Lipid nanovesicles, including cell-derived nanovesicles and synthetic lipid nanovesicles, are highly biocompatible and can penetrate BSCB, and are therefore effective delivery systems for targeted treatment of SCI. We summarize the progress of lipid nanovesicles for the targeted treatment of SCI, discuss their advantages and challenges, and provide a perspective on the application of lipid nanovesicles for SCI treatment. Although most of the lipid nanovesicle-based therapy of SCI is still in preclinical studies, this low immunogenicity, low toxicity, and highly engineerable nanovesicles will hold great promise for future spinal cord injury treatments.

Nanodrugs for the Treatment of Ischemic Stroke: A Systematic Review

Ischemic stroke, a significant neurovascular disorder, currently lacks effective restorative medication. However, recently developed nanomedicines bring renewed promise for alleviating ischemia's effects and facilitating the healing of neurological and physical functions. The aim of this systematic review was to evaluate the efficacy of nanotherapies in animal models of stroke and their potential impact on future stroke therapies. We also assessed the scientific quality of current research focused on nanoparticle-based treatments for ischemic stroke in animal models. We summarized the effectiveness of nanotherapies in these models, considering multiple factors such as their anti-inflammatory, antioxidant, and angiogenetic properties, as well as their safety and biodistribution. We conclude that the application of nanomedicines may reduce infarct size and improve neurological function post-stroke without causing significant organ toxicity.

Exosomes in brain diseases: Pathogenesis and therapeutic targets

Exosomes are extracellular vesicles with diameters of about 100 nm that are naturally secreted by cells into body fluids. They are derived from endosomes and are wrapped in lipid membranes. Exosomes are involved in intracellular metabolism and intercellular communication. They contain nucleic acids, proteins, lipids, and metabolites from the cell microenvironment and cytoplasm. The contents of exosomes can reflect their cells' origin and allow the observation of tissue changes and cell states under disease conditions. Naturally derived exosomes have specific biomolecules that act as the "fingerprint" of the parent cells, and the contents changed under pathological conditions can be used as biomarkers for disease diagnosis. Exosomes have low immunogenicity, are small in size, and can cross the blood-brain barrier. These characteristics make exosomes unique as engineering carriers. They can incorporate therapeutic drugs and achieve targeted drug delivery. Exosomes as carriers for targeted disease therapy are still in their infancy, but exosome engineering provides a new perspective for cell-free disease therapy. This review discussed exosomes and their relationship with the occurrence and treatment of some neuropsychiatric diseases. In addition, future applications of exosomes in the diagnosis and treatment of neuropsychiatric disorders were evaluated in this review.

Conjugation, Prodrug, and Co-Administration Strategies in Support of Nanotechnologies to Improve the Therapeutic Efficacy of Phytochemicals in the Central Nervous System

Phytochemicals, produced as secondary plant metabolites, have shown interesting potential therapeutic activities against neurodegenerative diseases and cancer. Unfortunately, poor bioavailability and rapid metabolic processes compromise their therapeutic use, and several strategies are currently proposed for overcoming these issues. The present review summarises strategies for enhancing the central nervous system's phytochemical efficacy. Particular attention has been paid to the use of phytochemicals in combination with other drugs (co-administrations) or administration of phytochemicals as prodrugs or conjugates, particularly when these approaches are supported by nanotechnologies exploiting conjugation strategies with appropriate targeting molecules. These aspects are described for polyphenols and essential oil components, which can improve their loading as prodrugs in nanocarriers, or be part of nanocarriers designed for targeted co-delivery to achieve synergistic anti-glioma or anti-neurodegenerative effects. The use of in vitro models, able to simulate the blood-brain barrier, neurodegeneration or glioma, and useful for optimizing innovative formulations before their in vivo administration via intravenous, oral, or nasal routes, is also summarised. Among the described compounds, quercetin, curcumin, resveratrol, ferulic acid, geraniol, and cinnamaldehyde can be efficaciously formulated to attain brain-targeting characteristics, and may therefore be therapeutically useful against glioma or neurodegenerative diseases.

Biomimetic oxygen-boosted hybrid membrane nanovesicles as the treatment strategy for ischemic stroke with the concept of the neurovascular unit

The pathogenesis of ischemic cerebrovascular disease has revealed that ischemic stroke often leads to deprivation of oxygen, blood-brain barrier (BBB) damage and enhanced inflammatory activation, eventually causing severe brain tissue damage. Herein, we prepared hybrid membrane nanovesicles (YC-1@[RBC-PL] NVs) composed of red blood cell (RBC) membrane and platelet (PL) membrane encapsulating hypoxia inducible factor-1α (HIF-1α) inhibitor YC-1 for contributing to the protection of the neurovascular unit (NVU) in ischemic stroke. YC-1@[RBC-PL] NVs targeted the ischemic brain by the thrombus targeting properties of PL membrane and relieved the hypoxia inside ischemic brain in the presence of YC-1 and catalase in YC-1@[RBC-PL] NVs. Finally, YC-1@[RBC-PL] NVs attenuated ischemic injury to NVU by reducing infarct volume, preserving BBB integrity, and blocking activation of astrocyte and microglia in a middle cerebral artery occlusion/reperfusion (MCAO/R) model.

Elabela, a Novel Peptide, Exerts Neuroprotective Effects Against Ischemic Stroke Through the APJ/miR-124-3p/CTDSP1/AKT Pathway

Elabela (ELA), which is the second endogenous peptide ligand of the apelin receptor (APJ) to be discovered, has been widely studied for potential use as a therapeutic peptide. However, its role in ischemic stroke (IS), which is a leading cause of disability and death worldwide and has limited therapeutic options, is uncertain. The aim of the present study was to investigate the beneficial effects of ELA on neuron survival after ischemia and the underlying molecular mechanisms. Primary cortical neurons were isolated from the cerebral cortex of pregnant C57BL/6J mice. Flow cytometry and immunofluorescence showed that ELA inhibited oxygen-glucose deprivation (OGD) -induced apoptosis and axonal damage in vitro. Additionally, analysis of the Gene Expression Omnibus database revealed that the expression of microRNA-124-3p (miR-124-3p) was decreased in blood samples from patients with IS, while the expression of C-terminal domain small phosphatase 1 (CTDSP1) was increased. These results indicated that miR-124-3p and CTDSP1 were related to ischemic stroke, and there might be a negative regulatory relationship between them. Then, we found that ELA significantly elevated miR-124-3p expression, suppressed CTDSP1 expression, and increased p-AKT expression by binding to the APJ receptor under OGD in vitro. A dual-luciferase reporter assay confirmed that CTDSP1 was a direct target of miR-124-3p. Furthermore, adenovirus-mediated overexpression of CTDSP1 exacerbated neuronal apoptosis and axonal damage and suppressed AKT phosphorylation, while treatment with ELA or miR-124-3p mimics reversed these effects. In conclusion, these results indicated that ELA could alleviate neuronal apoptosis and axonal damage by upregulating miR-124-3p and activating the CTDSP1/AKT signaling pathway. This study, for the first time, verified the protective effect of ELA against neuronal injury after ischemia and revealed the underlying mechanisms. We demonstrated the potential for the use of ELA as a therapeutic agent in the treatment of ischemic stroke.

Modification of Extracellular Vesicle Surfaces: An Approach for Targeted Drug Delivery

Extracellular vesicles (EVs) are a promising drug delivery vehicle candidate because of their natural origin and intrinsic function of transporting various molecules between different cells. Several advantages of the EV delivery platform include enhanced permeability and retention effect, efficient interaction with recipient cells, the ability to traverse biological barriers, high biocompatibility, high biodegradability, and low immunogenicity. Furthermore, EV membranes share approximately similar structures and contents to the cell membrane, which allows surface modification of EVs, an approach to enable specific targeting. Enhanced drug accumulation in intended sites and reduced adverse effects of chemotherapeutic drugs are the most prominent effects of targeted drug delivery. In order to improve the targeting ability of EVs, chemical modification and genetic engineering are the most adopted methods to date. Diverse chemical methods are employed to decorate EV surfaces with various ligands such as aptamers, carbohydrates, peptides, vitamins, and antibodies. In this review, we introduce the biogenesis, content, and cellular pathway of natural EVs and further discuss the genetic modification of EVs, and its challenges. Furthermore, we provide a comprehensive deliberation on the various chemical modification methods for improved drug delivery, which are directly related to increasing the therapeutic index.

Engineered Extracellular Vesicles as a Targeted Delivery Platform for Precision Therapy

Extracellular vesicles (EVs)-based cell-free strategy has shown therapeutic potential in tissue regeneration. Due to their important roles in intercellular communications and their natural ability to shield cargos from degradation, EVs are also emerged as novel delivery vehicles for various bioactive molecules and drugs. Accumulating studies have revealed that EVs can be modified to enhance their efficacy and specificity for the treatment of many diseases. Engineered EVs are poised as the next generation of targeted delivery platform in the field of precision therapy. In this review, the unique properties of EVs are overviewed in terms of their biogenesis, contents, surface features and biological functions, and the recent advances in the strategies of engineered EVs construction are summarized. Additionally, we also discuss the potential applications of engineered EVs in targeted therapy of cancer and damaged tissues, and evaluate the opportunities and challenges for translating them into clinical practice.

Exosomes; multifaceted nanoplatform for targeting brain cancers

At the moment, anaplastic changes within the brain are challenging due to the complexity of neural tissue, leading to the inefficiency of therapeutic protocols. The existence of a cellular interface, namely the blood-brain barrier (BBB), restricts the entry of several macromolecules and therapeutic agents into the brain. To date, several nano-based platforms have been used in laboratory settings and in vivo conditions to overcome the barrier properties of BBB. Exosomes (Exos) are one-of-a-kind of extracellular vesicles with specific cargo to modulate cell bioactivities in a paracrine manner. Regarding unique physicochemical properties and easy access to various biofluids, Exos provide a favorable platform for drug delivery and therapeutic purposes. Emerging data have indicated that Exos enable brain penetration of selective cargos such as bioactive factors and chemotherapeutic compounds. Along with these statements, the application of smart delivery approaches can increase delivery efficiency and thus therapeutic outcomes. Here, we highlighted the recent advances in the application of Exos in the context of brain tumors.

Exosomes as biomarkers and therapeutic measures for ischemic stroke

Ischemic stroke (IS) is the leading cause of long-term disability in the world and characterized by high morbidity, recurrence, complications, and mortality. Due to the lack of early diagnostic indicators, limited therapeutic measures and inadequate prognostic indicators, the diagnosis and treatment of IS remains a particular challenge at present. It has recently been reported that exosomes (EXOs) play a significant role in the pathogenesis and treatment of IS. The purpose of this paper is to probe the role of EXOs in diagnostic biomarkers and therapeutic measures for IS and to provide innovative ideas for improving the prognosis of IS.

Role of Circulating Exosomes in Cerebrovascular Diseases: A Comprehensive Review

Exosomes are lipid bilayer vesicles that contain multiple macromolecules secreted by the parent cells and play a vital role in intercellular communication. In recent years, the function of exosomes in cerebrovascular diseases (CVDs) has been intensively studied. Herein, we briefly review the current understanding of exosomes in CVDs. We discuss their role in the pathophysiology of the diseases and the value of the exosomes for clinical applications as biomarkers and potential therapies.

Analysis of the Research Hotspot of Exosomes in Cardiovascular Disease: A Bibliometric-based Literature Review

OBJECTIVE

To investigate the current status and development trend of research on exosomes in cardiovascular disease (CVD) using bibliometric analysis and to elucidate trending research topics.

METHODS

Research articles on exosomes in CVD published up to April 2022 were retrieved from the Web of Science database. Data were organized using Microsoft Office Excel 2019. CiteSpace 6.1 and VOSviewer 1.6.18 were used for bibliometric analysis and result visualization.

RESULTS

Overall, 256 original research publications containing 190 fundamental research publications and 66 clinical research publications were included. "Extracellular vesicle" was the most frequent research keyword, followed by "microrna," "apoptosis," and "angiogenesis." Most publications were from China (187, 73.05%), followed by the United States (57, 22.27%), the United Kingdom (7, 2.73%), and Japan (7, 2.73%). A systematic review of the publications revealed that myocardial infarction and stroke were the most popular topics and that exosomes and their contents, such as microRNAs (miRNAs), play positive roles in neuroprotection, inhibition of autophagy and apoptosis, promotion of angiogenesis, and protection of cardiomyocytes.

CONCLUSION

Research on exosomes in CVD has attracted considerable attention, with China having the most published studies. Fundamental research has focused on CVD pathogenesis; exosomes regulate the progression of CVD through biological processes, such as the inflammatory response, autophagy, and apoptosis. Clinical research has focused on biomarkers for CVD; studies on using miRNAs in exosomes as disease markers for diagnosis could become a future trend.

Exosomes in pathogenesis, diagnosis, and therapy of ischemic stroke

Ischemic stroke is one of the major contributors to death and disability worldwide. Thus, there is an urgent need to develop early brain tissue perfusion therapies following acute stroke and to enhance functional recovery in stroke survivors. The morbidity, therapy, and recovery processes are highly orchestrated interactions involving the brain with other tissues. Exosomes are natural and ideal mediators of intercellular information transfer and recognized as biomarkers for disease diagnosis and prognosis. Changes in exosome contents express throughout the physiological process. Accumulating evidence demonstrates the use of exosomes in exploring unknown cellular and molecular mechanisms of intercellular communication and organ homeostasis and indicates their potential role in ischemic stroke. Inspired by the unique properties of exosomes, this review focuses on the communication, diagnosis, and therapeutic role of various derived exosomes, and their development and challenges for the treatment of cerebral ischemic stroke.

Protective role of engineered extracellular vesicles loaded quercetin nanoparticles as anti-viral therapy against SARS-CoV-2 infection: A prospective review

Quercetin (QCT) is a naturally occurring phenolic flavonoid compound with inbuilt characteristics of antioxidant, anti-inflammatory, and immune protection. Several recent studies have shown that QCT and QCTits nanoparticles have therapeutic potential against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Novel therapeutics also include the implication of extracellular vesicles (EVs) to protect from SARS-CoV-2 viral infection. This article highlighted the therapeutic/prophylactic potential of engineered EVs loaded with QCT against SARS-CoV-2 infection. Several biotechnological engineering approaches are available to deliver EVs loaded with QCT nanoparticles. Among these biotechnological advances, a specific approach with significantly higher efficiency and yield has to be opted to fabricate such drug delivery of nano molecules, especially to combat SARS-CoV-2 infection. The current treatment regime protects the human body from virus infection but has some limitations including drugs and long-term steroid side effects. However, the vaccine strategy is somehow effective in inhibiting the spread of coronavirus disease-19 (COVID-19) infection. Moreover, the proposed exosomal therapy met the current need to repair the damaged tissue along with inhibition of COVID-19-associated complications at the tissue level. These scientific findings expand the possibilities and predictability of developing a novel and cost-effective therapeutic approach that combines the dual molecule, EVs and QCT nanoparticles, to treat SARS-CoV-2 infection. Therefore, the most suitable engineering method to fabricate such a drug delivery system should be better understood before developing novel therapeutics for clinical purposes.

M1 Microglia Induced Neuronal Injury on Ischemic Stroke via Mitochondrial Crosstalk between Microglia and Neurons

Among the middle-aged and senile populations, ischemic stroke (IS) is a frequently occurring acute condition of the cerebrovascular system. Traditionally, it is recognized that when stroke occurs, microglia are activated into M1 phenotype and release cytotoxic cytokines, reactive oxygen species, proteases, and other factors, thus exacerbating the injury by further destroying or killing nearby neurons. In the latest research, the crucial role of the intercellular mitochondrial crosstalk on the stroke management has been demonstrated. Therefore, we tried to clarify mitochondrial crosstalk between microglia and neurons, and evaluated M1 microglial mitochondria-mediated neurological performance in transient middle cerebral artery occlusion (tMCAO) rats. We found that when microglia was activated into the proinflammatory M1 type after stroke, mitochondrial fission process was accelerated, and damaged mitochondria were released, further transferred to neurons and fused with neuronal mitochondria. As a result, the function of neuronal mitochondria was damaged by decreasing adenosine triphosphate (ATP), mitochondria membrane potential, and increasing excessive reactive oxygen species (ROS), thus inducing mitochondria-mediated neuronal death and finally aggravating ischemia injury. Taken together, it provides a novel neuroglial crosstalk mechanism at the mitochondrial level.

Nanoengineering facilitating the target mission: targeted extracellular vesicles delivery systems design

Precision medicine has put forward the proposition of "precision targeting" for modern drug delivery systems. Inspired by techniques from biology, pharmaceutical sciences, and nanoengineering, numerous targeted drug delivery systems have been developed in recent decades. But the large-scale applications of these systems are limited due to unsatisfactory targeting efficiency, cytotoxicity, easy removability, and instability. As such, the natural endogenous cargo delivery vehicle-extracellular vesicles (EVs)-have sparked significant interest for its unique inherent targeting properties, biocompatibility, transmembrane ability, and circulatory stability. The membranes of EVs are enriched for receptors or ligands that interact with target cells, which endows them with inherent targeting mission. However, most of the natural therapeutic EVs face the fate of being cleared by macrophages, resulting in off-target. Therefore, the specificity of natural EVs delivery systems urgently needs to be further improved. In this review, we comprehensively summarize the inherent homing mechanisms of EVs and the effects of the donor cell source and administration route on targeting specificity. We then go over nanoengineering techniques that modify EVs for improving specific targeting, such as source cell alteration and modification of EVs surface. We also highlight the auxiliary strategies to enhance specificity by changing the external environment, such as magnetic and photothermal. Furthermore, contemporary issues such as the lack of a gold standard for assessing targeting efficiency are discussed. This review will provide new insights into the development of precision medicine delivery systems.

Synthesis and evaluation of glycosylated quercetin to enhance neuroprotective effects on cerebral ischemia-reperfusion

Quercetin (Que), a polyphenolic flavonoid compound with antioxidant properties has been explicated to have neuroprotective effects on neuronal injury/neurodegenerative diseases. However, low water-solubility, instability and inability to cross the blood-brain barrier (BBB) imped its application. To enhance the neuroprotective effects and improve the potential application of quercetins as a nutraceutical or medicine, we designed and synthesized two types of glycosylated quercetins--Glu-Que and 2Glu-Que through click reaction. Glu-Que and 2Glu-Que improved the water solubility and stability of quercetin, as well as alleviating H₂O₂-induced neurotoxicity by increasing the cell viability of PC12 cells and reducing the ROS generation. What's more, glycosylated quercetins enhanced neuroprotective effects on cerebral ischemia-reperfusion (I/R). Among the two types of glycosylated quercetin, 2Glu-Que displayed higher neuroprotective potential than Glu-Que. In conclusion, the glycosylated quercetin 2Glu-Que, with better water solubility, bioavailability and brain-targeting ability, significantly enhanced the neuroprotective effects of quercetin, making it a promising nutraceutical or candidate drug in neuroprotection.

Alteration of brain functional networks induced by electroacupuncture stimulation in rats with ischemia–reperfusion: An independent component analysis

Motor dysfunction is the major sequela of ischemic stroke. Motor recovery after stroke has been shown to be associated with remodeling of large-scale brain networks, both functionally and structurally. Electroacupuncture (EA) is a traditional Chinese medicine application that has frequently been recommended as an alternative therapy for ischemic stroke and is reportedly effective for alleviating motor symptoms in patients. In the present study, the effect of EA on the alterations of functional resting state networks (RSNs) was explored after middle cerebral artery occlusion/reperfusion (MCAO/R) injury using resting-state functional MRI. Rats were randomly assigned to three groups, including the sham group, MCAO/R group and MCAO/R+EA group. The ladder rung walking test was conducted prior to and after modeling to assess behavioral changes. RSNs were identified based on the independent component analysis (ICA) performed on the fMRI data from groups. EA treatment effectively reduced the occurrence of contralateral forelimb foot faults. Furthermore, our results suggested the disrupted function of the whole-brain network following ischemic stroke and the modulatory effect of acupuncture. The sensorimotor network (SMN), interoceptive network (IN), default mode network (DMN) and salience network (SN) were related to the therapeutic effect of EA on stroke recovery. Collectively, our findings confirmed the effect of EA on motor function recovery after cerebral ischemia reperfusion and shed light on the assessment of EA intervention-induced effects on brain networks. This study provides neuroimaging evidence to explain the therapeutic effects of EA in ischemic stroke and will lay the groundwork for further studies.

Bioengineering exosomes for treatment of organ ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is a leading cause of death worldwide. It arises from blood reflowing after tissue hypoxia induced by ischemia that causes severe damages due to the accumulation of reactive oxygen species and the activation of inflammatory responses. Exosomes are the smallest members of the extracellular vesicles' family, which originate from nearly all eukaryotic cells. Exosomes have a great potential in the treatment of I/R injury either in native or modified forms. Native exosomes are secreted by different cell types, such as stem cells, and contain components such as specific miRNA molecules with tissue protective properties. On the other hand, exosome bioengineering has recently received increased attention in context of current advances in the purification, manipulation, biological characterization, and pharmacological applications. There are various pre-isolation and post-isolation manipulation approaches that can be utilized to increase the circulation half-life of exosomes or the availability of their bioactive cargos in the target site. In this review, the various therapeutic actions of native exosomes in different I/R injury will be discussed first. Exosome bioengineering approaches will then be explained, including pre- and post-isolation manipulation methods, applicability for delivery of bioactive agents to injured tissue, clinical translation issues, and future perspectives.

Neuroprotective Effects of Quercetin on Ischemic Stroke: A Literature Review

Ischemic stroke (IS) is characterized by high recurrence and disability; however, its therapies are very limited. As one of the effective methods of treating acute attacks of IS, intravenous thrombolysis has a clear time window. Quercetin, a flavonoid widely found in vegetables and fruits, inhibits immune cells from secreting inflammatory cytokines, thereby reducing platelet aggregation and limiting inflammatory thrombosis. In pre-clinical studies, it has been shown to exhibit neuroprotective effects in patients with ischemic brain injury. However, its specific mechanism of action remains unknown. Therefore, this review aims to use published data to elucidate the potential value of quercetin in patients with ischemic brain injury. This article also reviews the plant sources, pharmacological effects, and metabolic processes of quercetin in vivo, thus focusing on its mechanism in inhibiting immune cell activation and inflammatory thrombosis as well as promoting neuroprotection against ischemic brain injury.

Research status and future prospects of extracellular vesicles in primary Sjögren's syndrome

Primary Sjögren’s syndrome (pSS) is a diffuse connective tissue disease characterized by the invasion of exocrine glands such as lacrimal and salivary glands, abnormal proliferation of T and B lymphocytes, and infiltration of tissue lymphocytes. With the development of modern medicine, although research on the pathogenesis, diagnosis, and treatment of pSS has made significant progress, its pathogenesis has not been fully understood. Meanwhile, in the era of individualized treatment, it remains essential to further explore early diagnosis and treatment methods. Exosomes, small vesicles containing proteins and nucleic acids, are a subtype of extracellular vesicles secreted by various cells and present in various body fluids. Exosomes contribute to a variety of biological functions, including intercellular signal transduction and pathophysiological processes, and may play a role in immune tolerance. Therefore, exosomes are key to understanding the pathogenesis of diseases. Exosomes can also be used as a therapeutic tool for pSS because of their biodegradability, low immunogenicity and toxicity, and the ability to bypass the blood–brain barrier, implying the prospect of a broad application in the context of pSS. Here, we systematically review the isolation, identification, tracing, and mode of action of extracellular vesicles, especially exosomes, as well as the research progress in the pathogenesis, diagnosis, and treatment of pSS.