Microglia exosomal miRNA-137 attenuates ischemic brain injury through targeting Notch1

Engineered and Mimicked Extracellular Nanovesicles for Therapeutic Delivery

Exosomes are spherical extracellular nanovesicles with an endosomal origin and unilamellar lipid-bilayer structure with sizes ranging from 30 to 100 nm. They contain a large range of proteins, lipids, and nucleic acid species, depending on the state and origin of the extracellular vesicle (EV)-secreting cell. EVs' function is to encapsulate part of the EV-producing cell content, to transport it through biological fluids to a targeted recipient, and to deliver their cargos specifically within the aimed recipient cells. Therefore, exosomes are considered to be potential biological drug-delivery systems that can stably deliver their cargo into targeted cells. Various cell-derived exosomes are produced for medical issues, but their use for therapeutic purposes still faces several problems. Some of these difficulties can be avoided by resorting to hemisynthetic approaches. We highlight here the uses of alternative exosome-mimes involving cell-membrane coatings on artificial nanocarriers or the hybridization between exosomes and liposomes. We also detail the drug-loading strategies deployed to make them drug-carrier systems and summarize the ongoing clinical trials involving exosomes or exosome-like structures. Finally, we summarize the open questions before considering exosome-like disposals for confident therapeutic delivery.

Exosome-mediated delivery and regulation in neurological disease progression

Exosomes (EXOs), membranous structures originating from diverse biological sources, have recently seized the attention of researchers due to their theranostic potential for neurological diseases. Released actively by various cells, including stem cells, adipose tissue, and immune cells, EXOs wield substantial regulatory influence over the intricate landscape of neurological complications, exhibiting both positive and negative modulatory effects. In AD, EXOs play a pivotal role in disseminating and breaking down amyloid-β protein. Moreover, EXOs derived from mesenchymal stem cells showcase a remarkable capacity to mitigate pro-inflammatory phenotypes by regulating miRNAs in neurodegenerative diseases. These vesicles possess the unique ability to traverse the blood-brain barrier, governing the aggregation of mutant huntingtin protein. Understanding the exosomal functions within the CNS holds significant promise for enhancing treatment efficacy in neurological diseases. This review intricately examines the regulatory mechanisms involving EXOs in neurological disease development, highlighting therapeutic prospects and exploring their utility in exosome-based nanomedicine for various neurological complications. Additionally, the review highlights the challenges associated with drug delivery to the brain, emphasizing the complexities inherent in this critical aspect of neurotherapeutics.

The role of neuroglial cells communication in ischemic stroke

Ischemic stroke is one of the leading causes of death and disability globally, but its treatment options are limited due to therapeutic window and reperfusion injury constraints. Microglia, astrocytes, and oligodendrocytes are the major components of the neurovascular unit, and there is substantial evidence suggesting their contributions to maintaining homeostasis in the central nervous system. Neuroglial cells participate in neuronal physiological functions and the repair of damaged neurons through various communication methods, including gap junctions, chemical signaling, and extracellular vesicles, in conjunction with other components of the neurovascular unit. Ischemia-induced microglia and astrocytes polarize into "M1/M2" and "A1/A2" phenotypes and exert neurotoxic or neuroprotective effects by releasing soluble factors, secreting extracellular vesicles, and forming syncytia networks in the acute (<72 h), subacute (>72 h), and chronic phases (>6 weeks). Apoptosis of oligodendrocytes due to ischemic hypoxia leads to white matter injury, causing long-term cognitive dysfunction, and promoting oligodendrogenesis is a crucial direction for achieving functional recovery in ischemic stroke. In this article, we summarize the cellular interactions following cerebral ischemia, analyze the roles of neuroglial cells through gap junctions, chemical signaling, and extracellular vesicles in different stages of ischemic stroke, and further explore strategies for intervening in ischemic stroke.

A recognition of exosomes as regulators of epigenetic mechanisms in central nervous system diseases

Exosomes, vesicular structures originating from cells, participate in the conveyance of proteins and nucleic acids. Presently, the centrality of epigenetic modifications in neurological disorders is widely acknowledged. Exosomes exert influence over various epigenetic phenomena, thereby modulating post-transcriptional regulatory processes contingent upon their constituent makeup. Consequently, the heightened attention directed toward exosomes as instigators of epigenetic alterations has burgeoned in recent years. Notably, exosomes serve as vehicles for delivering methyltransferases to recipient cells. More significantly, non-coding RNAs, particularly microRNAs (miRNAs), represent pivotal contents within exosomes, wielding the capacity to influence the expression of diverse factors within the cerebral milieu. The transfer of these exosomal contents amidst brain cells, encompassing neuronal cells and microglia, assumes a critical role in the genesis and progression of neurological disorders, also, this role is not limited to neurological disorders, it may deal with any human disease, such as cancer, and cardiovascular diseases. This review will concentrate on elucidating the regulation of exosome-induced epigenetic events and its subsequent ramifications for neurological diseases. A more profound comprehension of the involvement of exosome-mediated epigenetic regulation in neurological disorders contributes to a heightened awareness of the etiology and advancement of cerebral afflictions.

M2 Microglia-Derived Exosomes Protect Against Glutamate-Induced HT22 Cell Injury via Exosomal miR-124-3p

As one of the most serious complications of sepsis, sepsis-associated encephalopathy has not been effectively treated or prevented. Exosomes, as a new therapeutic method, play a protective role in neurodegenerative diseases, stroke and traumatic brain injury in recent years. The purpose of this study was to investigate the role of exosomes in glutamate (Glu)-induced neuronal injury, and to explore its mechanism, providing new ideas for the treatment of sepsis-associated encephalopathy. The neuron damage model induced by Glu was established, and its metabolomics was analyzed and identified. BV2 cells were induced to differentiate into M1 and M2 subtypes. After the exosomes from both M1-BV2 cells and M2-BV2 cells were collected, exosome morphological identification was performed by transmission electron microscopy and exosome-specific markers were also detected. These exosomes were then cocultured with HT22 cells. CCK-8 method and LDH kit were used to detect cell viability and toxicity. Cell apoptosis, mitochondrial membrane potential and ROS content were respectively detected by flow cytometry, JC-1 assay and DCFH-DA assay. MiR-124-3p expression level was detected by qRT-PCR and Western blot. Bioinformatics analysis and luciferase reporter assay predicted and verified the relationship between miR-124-3p and ROCK1 or ROCK2. Through metabolomics, 81 different metabolites were found, including fructose, GABA, 2, 4-diaminobutyric acid, etc. The enrichment analysis of differential metabolites showed that they were mainly enriched in glutathione metabolism, glycine and serine metabolism, and urea cycle. M2 microglia-derived exosomes could reduce the apoptosis, decrease the accumulation of ROS, restore the mitochondrial membrane potential and the anti-oxidative stress ability in HT22 cells induced by Glu. It was also found that the protective effect of miR-124-3p mimic on neurons was comparable to that of M2-EXOs. Additionally, M2-EXOs might carry miR-124-3p to target ROCK1 and ROCK2 in neurons, affecting ROCK/PTEN/AKT/mTOR signaling pathway, and then reducing Glu-induced neuronal apoptosis. M2 microglia-derived exosomes may protect HT22 cells against Glu-induced injury by transferring miR-124-3p into HT22 cells, with ROCK being a target gene for miR-124-3p.

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.

Exosomal OIP5-AS1 attenuates cerebral ischemia-reperfusion injury by negatively regulating TXNIP protein stability and inhibiting neuronal pyroptosis

BACKGROUND

Cerebral ischemia-reperfusion injury (CIRI) can cause neuronal apoptosis and lead to irreversible brain injury. Numerous lncRNAs have been reported to play important roles in CIRI, but it is unclear whether these lncRNAs can function through exosomes.

METHODS

In this study, we utilized the middle cerebral artery occlusion/reperfusion (MCAO/R) animal model and the oxygen-glucose deprivation/ reoxygenation (OGD/R) cell model. RNA sequencing was performed to screen for differentially expressed lncRNAs in M2 microglia-derived exosomes (M2-Exos). RNA pull-down, RNA immunoprecipitation, co-immunoprecipitation and ubiquitination assays were used to explore the molecular mechanism of OIP5-AS1 in alleviating CIRI.

RESULTS

M2-Exos could alleviate nerve injury and pyroptosis after CIRI in vitro and in vivo. OIP5-AS1 was found to be significantly up-regulated in M2-Exos and down-regulated in OGD/R neurons, MCAO/R mice and ischemic stroke patients. In MCAO/R mice, OIP5-AS1 could reduce cerebral infarct size, cerebral edema and mNSS scores, and inhibit the expression levels of pyroptosis-related proteins in brain tissue. TXNIP was confirmed to be a reliable binding protein of OIP5-AS1. OIP5-AS1 overexpression significantly attenuated MCAO/R-induced upregulation of TXNIP at the protein level, but not at the mRNA level. OIP5-AS1 promoted the TXNIP degradation process and increased the ubiquitination of TXNIP. ITCH could bind to TXNIP. ITCH overexpression or knockdown did not alter the mRNA level of TXNIP, but negatively regulated TXNIP expression at the protein level. ITCH accelerated the degradation and ubiquitination of TXNIP, which could be attenuated by OIP5-AS1 knockdown. OIP5-AS1 could improve neuronal damage and inhibit neuronal pyroptosis through TXNIP.

CONCLUSIONS

M2-Exo-derived OIP5-AS1 can induce TXNIP ubiquitination and degradation by recruiting ITCH, negatively regulate TXNIP protein stability, inhibit neuronal pyroptosis, and attenuate CIRI.

Exosomal miRNAs as Biomarkers of Ischemic Stroke

Exosomes are small lipid bilayer membrane particles released from all living cells into the extracellular environment. They carry several molecules and have a critical role in cell-cell communication under physiological and pathological conditions. In recent decades, exosomes, and especially their cargo, have emerged as a promising tool for several clinical conditions. However, the literature has become increasingly unambiguous in defining the role of exosomes in chronic cerebrovascular diseases. Because they can pass through the blood-brain barrier, they have great potential to reflect intracerebral changes. They can, thus, provide valuable insight into the mechanisms of central nervous system diseases. The purpose of this review is to describe the literature on the role of exosomal miRNA, which represents the most widely investigated exosomal biomarker, in strokes. First, we provide an overview of exosomes, from biology to isolation and characterization. Then, we describe the relationship between exosomes and stroke pathogenesis. Finally, we summarize the human studies evaluating exosomal miRNA biomarkers of stroke. Although the collective literature supports the potential use of exosomal miRNA as biomarkers of ischemic stroke, there are still several limitations hampering their introduction into clinical practice.

Role of Crosstalk between Glial Cells and Immune Cells in Blood-Brain Barrier Damage and Protection after Acute Ischemic Stroke

Blood-brain barrier (BBB) damage is the main pathological basis for acute ischemic stroke (AIS)-induced cerebral vasogenic edema and hemorrhagic transformation (HT). Glial cells, including microglia, astrocytes, and oligodendrocyte precursor cells (OPCs)/oligodendrocytes (OLs) play critical roles in BBB damage and protection. Recent evidence indicates that immune cells also have an important role in BBB damage, vasogenic edema and HT. Therefore, regulating the crosstalk between glial cells and immune cells would hold the promise to alleviate AIS-induced BBB damage. In this review, we first introduce the roles of glia cells, pericytes, and crosstalk between glial cells in the damage and protection of BBB after AIS, emphasizing the polarization, inflammatory response and crosstalk between microglia, astrocytes, and other glia cells. We then describe the role of glial cell-derived exosomes in the damage and protection of BBB after AIS. Next, we specifically discuss the crosstalk between glial cells and immune cells after AIS. Finally, we propose that glial cells could be a potential target for alleviating BBB damage after AIS and we discuss some molecular targets and potential strategies to alleviate BBB damage by regulating glial cells after AIS.

Disorders of the central nervous system: Insights from Notch and Nrf2 signaling

The functional complexity of the central nervous system (CNS) is unparalleled in living organisms. It arises from neural crest-derived cells that migrate by the exact route, leading to the formation of a complex network of neurons and glial cells. Recent studies have shown that novel crosstalk exists between the Notch1 and Nrf2 pathways and is associated with many neurological diseases. The Notch1-Nrf2 axis may act on nervous system development, and the molecular mechanism has recently been reported. In this review, we summarize the essential structure and function of the CNS. The significance of interactions between signaling pathways and between developmental processes like proliferation, apoptosis and migration in ensuring the correct development of the CNS is also presented. We primarily focus on research concerning possible mechanism of interaction between Notch1 and Nrf2 and the functions of Notch1-Nrf2 in neurons. There may be a direct interaction between Notch1 and NRF2, which is closely related to the crosstalk that occurs between them. The significance and potential applications of the Notch1-Nrf2 axis in abnormal development of the nervous system are been highlighten. We also discuss the molecular mechanisms by which the Notch1-Nrf2 axis controls the apoptosis, antioxidant pathway and differentiation of neurons to modulate the development of the nervous system. This information will lead to a better understanding of Notch1-Nrf2 axis signaling pathways in the nervous system and may facilitate the development of new therapeutic strategies.

Preconditioned extracellular vesicles from hypoxic microglia reduce poststroke AQP4 depolarization, disturbed cerebrospinal fluid flow, astrogliosis, and neuroinflammation

Background: Stroke stimulates reactive astrogliosis, aquaporin 4 (AQP4) depolarization and neuroinflammation. Preconditioned extracellular vesicles (EVs) from microglia exposed to hypoxia, in turn, reduce poststroke brain injury. Nevertheless, the underlying mechanisms of such effects are elusive, especially with regards to inflammation, AQP4 polarization, and cerebrospinal fluid (CSF) flow. Methods: Primary microglia and astrocytes were exposed to oxygen-glucose deprivation (OGD) injury. For analyzing the role of AQP4 expression patterns under hypoxic conditions, a co-culture model of astrocytes and microglia was established. Further studies applied a stroke model, where some mice also received an intracisternal tracer infusion of rhodamine B. As such, these in vivo studies involved the analysis of AQP4 polarization, CSF flow, astrogliosis, and neuroinflammation as well as ischemia-induced brain injury. Results: Preconditioned EVs decreased periinfarct AQP4 depolarization, brain edema, astrogliosis, and inflammation in stroke mice. Likewise, EVs promoted postischemic CSF flow and cerebral blood perfusion, and neurological recovery. Under in vitro conditions, hypoxia stimulated M2 microglia polarization, whereas EVs augmented M2 microglia polarization and repressed M1 microglia polarization even further. In line with this, astrocytes displayed upregulated AQP4 clustering and proinflammatory cytokine levels when exposed to OGD, which was reversed by preconditioned EVs. Reduced AQP4 depolarization due to EVs, however, was not a consequence of unspecific inflammatory regulation, since LPS-induced inflammation in co-culture models of astrocytes and microglia did not result in altered AQP4 expression patterns in astrocytes. Conclusions: These findings show that hypoxic microglia may participate in protecting against stroke-induced brain damage by regulating poststroke inflammation, astrogliosis, AQP4 depolarization, and CSF flow due to EV release.

Exosome-based crosstalk in glaucoma pathogenesis: a focus on oxidative stress and neuroinflammation

Exosomes are membrane-bound tiny particles that are released by all live cells that contain multiple signal molecules and extensively participate in numerous normal physical activities and pathologies. In glaucoma, the crucial role of exosome-based crosstalk has been primarily revealed in animal models and ex vivo cell studies in the recent decade. In the aqueous drainage system, exosomes derived from non-pigment ciliary epithelium act in an endocrine manner and specifically regulate the function of the trabecular meshwork to cope with persistent oxidative stress challenges. In the retina, a more complicated regulatory network among microglia, retinal neurons, retinal ganglial cells, retinal pigment epithelium, and other immune effector cells by exosomes are responsible for the elaborate modulation of tissue homeostasis under physical state and the widespread propagation of neuroinflammation and its consequent neurodegeneration in glaucoma pathogenesis. Accumulating evidence indicates that exosome-based crosstalk depends on numerous factors, including the specific cargos they carried (particularly micro RNA), concentration, size, and ionization potentials, which largely remain elusive. In this narrative review, we summarize the latest research focus of exosome-based crosstalk in glaucoma pathogenesis, the current research progress of exosome-based therapy for glaucoma and provide in-depth perspectives on its current research gap.

Exosomes derived from M2-type microglia ameliorate oxygen-glucose deprivation/reoxygenation-induced HT22 cell injury by regulating miR-124-3p/NCOA4-mediated ferroptosis

Background

Although it has been reported that miRNA carried by M2 microglial exosomes protects neurons from ischemia-reperfusion brain injury, the mechanism of action remains poorly understood. This study aimed to explore the miRNA signaling pathway by which M2-type microglia-derived exosomes (M2-exosomes) ameliorate oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cytotoxicity in HT22 cells.

Methods

BV2 microglia were induced by M2 polarization. Then, M2-exosomes were identified via transmission electron microscopy and special biomarker detection and co-cultured with HT22 cells. Cell proliferation was evaluated using the Cell Counting Kit-8 (CCK-8) assay. Intracellular concentrations of reactive oxygen species (ROS), Fe²⁺, glutathione (GSH), and malondialdehyde (MDA) were determined using dichlorofluorescein fluorescence and biochemical determination. miR-124-3p levels were determined using qRT-PCR, and protein expressions were examined via western blotting.

Results

OGD/R suppressed the proliferation and induced the accumulation of Fe²⁺, ROS, and MDA and reduction of GSH in mouse HT22 cells, suggesting ferroptosis of HT22 cells. OGD/R-induced changes in the above mentioned indexes was ameliorated by M2-exosomes but restored by the exosome inhibitor GW4869. M2-exosomes with (mimic-exo) or without miR-124-3p (inhibitor-exo) promoted and suppressed proliferation and ferroptosis-associated indexes of HT22 cells, respectively. Moreover, mimic-exo and inhibitor-exo inhibited and enhanced NCOA4 expression in HT22 cells, respectively. NCOA4 overexpression reversed the protective effects of miR-124-3p mimic-exo in OGD/R-conditioned cells. NCOA4 was targeted and regulated by miR-124-3p.

Conclusions

M2-exosome protects HT22 cells against OGD/R-induced ferroptosis injury by transferring miR-124-3p and NCOA4 into HT22 cells, with the latter being a target gene for miR-124-3p.

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.

Potassium Channels, Glucose Metabolism and Glycosylation in Cancer Cells

Potassium channels emerge as one of the crucial groups of proteins that shape the biology of cancer cells. Their involvement in processes like cell growth, migration, or electric signaling, seems obvious. However, the relationship between the function of K+ channels, glucose metabolism, and cancer glycome appears much more intriguing. Among the typical hallmarks of cancer, one can mention the switch to aerobic glycolysis as the most favorable mechanism for glucose metabolism and glycome alterations. This review outlines the interconnections between the expression and activity of potassium channels, carbohydrate metabolism, and altered glycosylation in cancer cells, which have not been broadly discussed in the literature hitherto. Moreover, we propose the potential mediators for the described relations (e.g., enzymes, microRNAs) and the novel promising directions (e.g., glycans-orinented drugs) for further research.

The Implications of Microglial Regulation in Neuroplasticity-Dependent Stroke Recovery

Stroke causes varying degrees of neurological deficits, leading to corresponding dysfunctions. There are different therapeutic principles for each stage of pathological development. Neuroprotection is the main treatment in the acute phase, and functional recovery becomes primary in the subacute and chronic phases. Neuroplasticity is considered the basis of functional restoration and neurological rehabilitation after stroke, including the remodeling of dendrites and dendritic spines, axonal sprouting, myelin regeneration, synapse shaping, and neurogenesis. Spatiotemporal development affects the spontaneous rewiring of neural circuits and brain networks. Microglia are resident immune cells in the brain that contribute to homeostasis under physiological conditions. Microglia are activated immediately after stroke, and phenotypic polarization changes and phagocytic function are crucial for regulating focal and global brain inflammation and neurological recovery. We have previously shown that the development of neuroplasticity is spatiotemporally consistent with microglial activation, suggesting that microglia may have a profound impact on neuroplasticity after stroke and may be a key therapeutic target for post-stroke rehabilitation. In this review, we explore the impact of neuroplasticity on post-stroke restoration as well as the functions and mechanisms of microglial activation, polarization, and phagocytosis. This is followed by a summary of microglia-targeted rehabilitative interventions that influence neuroplasticity and promote stroke recovery.

Regulation of Glial Function by Noncoding RNA in Central Nervous System Disease

Non-coding RNAs (ncRNAs) are a class of functional RNAs that play critical roles in different diseases. NcRNAs include microRNAs, long ncRNAs, and circular RNAs. They are highly expressed in the brain and are involved in the regulation of physiological and pathophysiological processes of central nervous system (CNS) diseases. Mounting evidence indicates that ncRNAs play key roles in CNS diseases. Further elucidating the mechanisms of ncRNA underlying the process of regulating glial function that may lead to the identification of novel therapeutic targets for CNS diseases.

The role of miRNAs in insulin resistance and diabetic macrovascular complications - A review

Diabetes is the most prevalent metabolic disturbance disease and has been regarded globally as one of the principal causes of mortality. Diabetes is accompanied by several macrovascular complications, including stroke, coronary artery disease (CAD), and cardiomyopathy as a consequence of atherosclerosis. The onset of type 2 diabetes is closely related to insulin resistance (IR). miRNAs have been linked to various metabolic processes, including glucose homeostasis, regulation of lipid metabolism, gluconeogenesis, adipogenesis, glucose transporter type 4 expression, insulin sensitivity, and signaling. Consequently, miRNA dysregulation mediates IR in some target organs, comprising liver, muscle, and adipose tissue. Moreover, miRNAs are crucial in developing diabetes and its associated macrovascular complications through their roles in several signaling pathways implicated in inflammation, apoptosis, cellular survival and migration, the proliferation of vascular smooth muscle cells, neurogenesis, angiogenesis, autophagy, oxidative stress, cardiac remodeling, and fibrosis. Therefore, the purpose of this review is to clarify the role of miRNAs in hepatic, muscle, and adipose tissue IR and explain their roles in the pathogenesis of macrovascular diabetic complications, including stroke, CAD, and cardiomyopathy. Also, explain their roles in gestational diabetes mellitus (GDM). Besides, this review discusses the latest updates on the alteration of miRNA expression in diabetic macrovascular complications.

Exosomes based strategies for brain drug delivery

Exosome application has emerged as a promising nanotechnology discipline for various diseases therapeutics and diagnoses. Owing to the natural properties of efficient drug delivery, higher biocompatibility, facile traversing of physiological barriers, and subtle side effects, exosomes shorten their way to clinical translation. Exosomes are nanoscale membrane-bound vesicles primarily involved in intercellular communication and exhibit natural blood-brain barrier (BBB) traversing ability, which enables their application as drug delivery vehicles for brain diseases treatment. Herein, we highlight recent exosome-based drug delivery endeavors for neurodegenerative diseases and brain cancer therapy, summarize the obstacles and future directions in clinical translation.

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.

Exosomal miR-145 and miR-885 Regulate Thrombosis in COVID-19

We hypothesized that exosomal microRNAs could be implied in the pathogenesis of thromboembolic complications in coronavirus disease 2019 (COVID-19). We isolated circulating exosomes from patients with COVID-19, and then we divided our population in two arms based on the D-dimer level on hospital admission. We observed that exosomal miR-145 and miR-885 significantly correlate with D-dimer levels. Moreover, we demonstrate that human endothelial cells express the main cofactors needed for the internalization of the "Severe acute respiratory syndrome coronavirus 2" (SARS-CoV-2), including angiotensin converting enzyme 2, transmembrane protease serine 2, and CD-147. Interestingly, human endothelial cells treated with serum from COVID-19 patients release significantly less miR-145 and miR-885, exhibit increased apoptosis, and display significantly impaired angiogenetic properties compared with cells treated with non-COVID-19 serum. Taken together, our data indicate that exosomal miR-145 and miR-885 are essential in modulating thromboembolic events in COVID-19. SIGNIFICANCE STATEMENT: This work demonstrates for the first time that two specific microRNAs (namely miR-145 and miR-885) contained in circulating exosomes are functionally involved in thromboembolic events in COVID-19. These findings are especially relevant to the general audience when considering the emerging prominence of post-acute sequelae of COVID-19 systemic manifestations known as Long COVID.

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.

MicroRNA-140-5p shuttled by microglia-derived extracellular vesicles attenuates subarachnoid hemorrhage-induced microglia activation and inflammatory response via MMD downregulation

BACKGROUND

It is documented that microglia-secreted extracellular vesicles (microglia-EVs) exert neuroprotection which is important following subarachnoid hemorrhage (SAH). Herein, we focused on the mechanism of microglia-EVs harboring microRNA-140-5p (miR-140-5p) in SAH development.

METHODS

After the successful establishment of SAH rats, neurological function was evaluated, and behaviors were observed. Serum inflammatory factors (IL-1β and TNF-α) were quantified by ELISA, followed by the detection of microglial polarization by immunofluorescence. The relationship between miR-140-5p and monocyte to macrophage differentiation-associated (MMD) was evaluated using luciferase assay. Following the extraction of microglia and microglia-EVs, the transferring of miR-140-5p by microglia-EVs was assessed by co-culture experiments. SAH rats were treated with the EVs sourced from microglia overexpressing miR-140-5p (microglia-EVs-miR-140-5p) or EVs sourced from miR-140-5p-deficient microglia (microglia-EVs-miR-140-5p inhibitor) for in vivo effect assessment.

RESULTS

Microglia-EVs inhibited microglia activation and secretion of TNF-α and IL-1β by delivering miR-140-5p. Microglia-EVs could transmit miR-140-5p into microglia. Furthermore, microglia-EVs-miR-140-5p reduced the expression of its target MMD, resulting in blocked inflammatory response and activation of microglia in SAH rats by disrupting the PI3K/AKT and Erk1/2 signaling.

CONCLUSION

In summary, microglia-EVs transmitted miR-140-5p into microglia to downregulate MMD and finally contributed to neuroprotection in SAH rats.

Neuronal and Glial Communication via Non-Coding RNAs: Messages in Extracellular Vesicles

Extracellular vesicles (EVs) have been increasingly recognized as essential players in cell communication in many organs and systems, including the central nervous system (CNS). A proper interaction between neural cells is fundamental in the regulation of neurophysiological processes and its alteration could induce several pathological phenomena, such as neurodegeneration, neuroinflammation, and demyelination. EVs contain and transfer complex molecular cargoes typical of their cells of origin, such as proteins, lipids, carbohydrates, and metabolites to recipient cells. EVs are also enriched in non-coding RNAs (e.g., microRNAs, lncRNAs, and circRNA), which were formerly considered as cell-intrinsic regulators of CNS functions and pathologies, thus representing a new layer of regulation in the cell-to-cell communication. In this review, we summarize the most recent and advanced studies on the role of EV-derived ncRNAs in the CNS. First, we report the potential of neural stem cell-derived ncRNAs as new therapeutic tools for neurorepair. Then, we discuss the role of neuronal ncRNAs in regulating glia activation, and how alteration in glial ncRNAs influences neuronal survival and synaptic functions. We conclude that EV-derived ncRNAs can act as intercellular signals in the CNS to either propagate neuroinflammatory waves or promote reparative functions.

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.

Exosomes in Cerebral Ischemia-Reperfusion Injury: Current Perspectives and Future Challenges

Cerebral ischemia impedes the functional or metabolic demands of the central nervous system (CNS), which subsequently leads to irreversible brain damage. While recanalization of blocked vessels recovers cerebral blood flow, it can also aggravate brain injury, termed as ischemia/reperfusion (I/R) injury. Exosomes, nanometric membrane vesicles, attracted wide attention as carriers of biological macromolecules. In the brain, exosomes can be secreted by almost all types of cells, and their contents can be altered during the pathological and clinical processes of cerebral I/R injury. Herein, we will review the current literature on the possible role of cargos derived from exosomes and exosomes-mediated intercellular communication in cerebral I/R injury. The PubMed and Web of Science databases were searched through January 2015. The studies published in English were identified using search terms including "exosomes", "cerebral ischemia-reperfusion injury", "brain ischemia-reperfusion injury", and "stroke". We will also focus on the potential therapeutic effects of stem cell-derived exosomes and underlying mechanisms in cerebral I/R injury. Meanwhile, with the advantages of low immunogenicity and cytotoxicity, high bioavailability, and the capacity to pass through the blood-brain barrier, exosomes also attract more attention as therapeutic modalities for the treatment of cerebral I/R injury.

Effects and Mechanisms of Exosomes from Different Sources in Cerebral Ischemia

Cerebral ischemia refers to the symptom of insufficient blood supply to the brain. Cells of many different origins participate in the process of repairing damage after cerebral ischemia occurs, in which exosomes secreted by the cells play important roles. For their characteristics, such as small molecular weight, low immunogenicity, and the easy penetration of the blood-brain barrier (BBB), exosomes can mediate cell-to-cell communication under pathophysiological conditions. In cerebral ischemia, exosomes can reduce neuronal damage and improve the brain microenvironment by regulating inflammation, mediating pyroptosis, promoting axonal growth, and stimulating vascular remodeling. Therefore, exosomes have an excellent application prospect for the treatment of cerebral ischemia. This article reviews the roles and mechanisms of exosomes from different sources in cerebral ischemia and provides new ideas for the prevention and treatment of cerebral ischemia.

The role of microglial exosomes in brain injury

Microglia are involved in immune responses to central nervous system (CNS) injury. Meanwhile, exosomes derived from microglia are important mediators of information and material exchange in brain, which play an important role in neuroprotective or damaging effects. Microglial exosomes contain a variety of molecular cargos, including microRNAs, soluble proteins, and lipids, which have regulatory effects on other types of cells and microenvironment in brain. In this review, we summarized microglial exosome characteristics, release patterns, pro-proliferative and pro-apoptotic effects on neurons and other glial cells, immunomodulatory effects, and regulation of the extracellular microenvironment. Understanding the relationship between microglia exosomes and brain injury can provide new targets for clinical treatment.

Mesenchymal stem cell therapy for ischemic stroke: Novel insight into the crosstalk with immune cells

Stroke, a cerebrovascular accident, is prevalent and the second highest cause of death globally across patient populations; it is as a significant cause of morbidity and mortality. Mesenchymal stem cell (MSC) transplantation is emerging as a promising treatment for alleviating neurological deficits, as indicated by a great number of animal and clinical studies. The potential of regulating the immune system is currently being explored as a therapeutic target after ischemic stroke. This study will discuss recent evidence that MSCs can harness the immune system by interacting with immune cells to boost neurologic recovery effectively. Moreover, a notion will be given to MSCs participating in multiple pathological processes, such as increasing cell survival angiogenesis and suppressing cell apoptosis and autophagy in several phases of ischemic stroke, consequently promoting neurological function recovery. We will conclude the review by highlighting the clinical opportunities for MSCs by reviewing the safety, feasibility, and efficacy of MSCs therapy.

Molecular Mechanism of the Protective Effects of M2 Microglia on Neurons: A Review Focused on Exosomes and Secretory Proteins

Microglia, as innate immune cells in the brain, closely monitor changes in the internal environment and participate in the maintenance of homeostasis in the central nervous system (CNS). Microglia can be polarized to the M1 or M2 phenotype in response to various stimuli in vivo or in vitro, affecting the functions of peripheral neurons. M2 microglia have attracted increasing attention in recent years owing to their beneficial effects on various diseases and injuries of the CNS, such as traumatic brain injury, stroke, Alzheimer's disease and multiple sclerosis. They exert neuroprotective effects by various mechanisms, e.g., suppressing inflammation, promoting the degradation of misfolded and aggregated proteins, promoting neurite growth, enhancing neurogenesis, inhibiting autophagy and apoptosis, promoting myelination, maintaining blood-brain barrier integrity, and enhancing phagocytic activity.This review summarizes the molecular mechanisms by which M2 microglia exert protective effects on neurons and provides a reference for the selection of therapeutic targets for CNS diseases.

Exosomes and mimics as novel delivery platform for cancer therapy

Exosomes are nano-sized biological extracellular vesicles transmitting information between cells and constituting a new intercellular communication mode. Exosomes have many advantages as an ideal drug delivery nanocarrier, including good biocompatibility, permeability, low toxicity, and low immunogenicity. Recently, exosomes have been used to deliver chemotherapeutic agents, natural drugs, nucleic acid drugs, and other antitumor drugs to treat many types of tumors. Due to the limited production of exosomes, synthetic exosome-mimics have been developed as an ideal platform for drug delivery. This review summarizes recent advances in the application of exosomes and exosome-mimics delivering therapeutic drugs in treating cancers.

Neuroprotective and Neurotoxic Effects of Glial-Derived Exosomes

Exosomes derived from glial cells such as astrocytes, microglia, and oligodendrocytes can modulate cell communication in the brain and exert protective or neurotoxic effects on neurons, depending on the environmental context upon their release. Their isolation, characterization, and analysis under different conditions in vitro, in animal models and samples derived from patients has allowed to define the participation of other molecular mechanisms behind neuroinflammation and neurodegeneration spreading, and to propose their use as a potential diagnostic tool. Moreover, the discovery of specific molecular cargos, such as cytokines, membrane-bound and soluble proteins (neurotrophic factors, growth factors, misfolded proteins), miRNA and long-non-coding RNA, that are enriched in glial-derived exosomes with neuroprotective or damaging effects, or their inhibitors can now be tested as therapeutic tools. In this review we summarize the state of the art on how exosomes secretion by glia can affect neurons and other glia from the central nervous system in the context of neurodegeneration and neuroinflammation, but also, on how specific stress stimuli and pathological conditions can change the levels of exosome secretion and their properties.

The Emerging Role of Extracellular Vesicle Derived From Neurons/Neurogliocytes in Central Nervous System Diseases: Novel Insights Into Ischemic Stroke

Neurons and neurogliocytes (oligodendrocytes, astrocytes, and microglia) are essential for maintaining homeostasis of the microenvironment in the central nervous system (CNS). These cells have been shown to support cell-cell communication via multiple mechanisms, most recently by the release of extracellular vesicles (EVs). Since EVs carry a variety of cargoes of nucleic acids, lipids, and proteins and mediate intercellular communication, they have been the hotspot of diagnosis and treatment. The mechanisms underlying CNS disorders include angiogenesis, autophagy, apoptosis, cell death, and inflammation, and cell-EVs have been revealed to be involved in these pathological processes. Ischemic stroke is one of the most common causes of death and disability worldwide. It results in serious neurological and physical dysfunction and even leads to heavy economic and social burdens. Although a large number of researchers have reported that EVs derived from these cells play a vital role in regulating multiple pathological mechanisms in ischemic stroke, the specific interactional relationships and mechanisms between specific cell-EVs and stroke treatment have not been clearly described. This review aims to summarize the therapeutic effects and mechanisms of action of specific cell-EVs on ischemia. Additionally, this study emphasizes that these EVs are involved in stroke treatment by inhibiting and activating various signaling pathways such as ncRNAs, TGF-β1, and NF-κB.

Increased miR-155 in Microglial Exosomes Following Heat Stress Accelerates Neuronal Autophagy via Their Transfer Into Neurons

Background

Heat stroke is the outcome of excessive heat stress, which results in core temperatures exceeding 40°C accompanied by a series of complications. The brain is particularly vulnerable to damage from heat stress. In our previous studies, both activated microglia and increased neuronal autophagy were found in the cortices of mice with heat stroke. However, whether activated microglia can accelerate neuronal autophagy under heat stress conditions is still unknown. In this study, we aimed to investigate the underlying mechanism that caused neuronal autophagy upregulation in heat stroke from the perspective of exosome-mediated intercellular communication.

Methods

In this study, BV2 and N2a cells were used instead of microglia and neurons, respectively. Exosomes were extracted from BV2 culture supernatants by ultracentrifugation and then characterized via transmission electron microscopy, nanoparticle tracking analysis and Western blotting. N2a cells pretreated with/without miR-155 inhibitor were cocultured with microglial exosomes that were treated with/without heat stress or miR-155 overexpression and subsequently subjected to heat stress treatment. Autophagy in N2a cells was assessed by detecting autophagosomes and autophagy-related proteins through transmission electron microscopy, immunofluorescence, and Western blotting. The expression of miR-155 in BV2 and BV2 exosomes and N2a cells was measured using real-time reverse transcription polymerase chain reaction. Target binding analysis was verified via a dual-luciferase reporter assay.

Results

N2a autophagy moderately increased in response to heat stress and accelerated by BV2 cells through transferring exosomes to neurons. Furthermore, we found that neuronal autophagy was positively correlated with the content of miR-155 in microglial exosomes. Inhibition of miR-155 partly abolished autophagy in N2a cells, which was increased by coculture with miR-155-upregulated exosomes. Mechanistic analysis confirmed that Rheb is a functional target of miR-155 and that microglial exosomal miR-155 accelerated heat stress-induced neuronal autophagy mainly by regulating the Rheb-mTOR signaling pathway.

Conclusion

Increased miR-155 in microglial exosomes after heat stroke can induce neuronal autophagy via their transfer into neurons. miR-155 exerted these effects by targeting Rheb, thus inhibiting the activity of mTOR signaling. Therefore, miR-155 could be a promising target for interventions of neuronal autophagy after heat stroke.

Overexpression of microRNA-381-3p ameliorates hypoxia/ischemia-induced neuronal damage and microglial inflammation via regulating the C-C chemokine receptor type 2 /nuclear transcription factor-kappa B axis

microRNAs, as small endogenous RNAs, influence umpteen sophisticated cellular biological functions regarding neurodegenerative and cerebrovascular diseases. Here, we interrogated miR-381-3p’s influence on BV2 activation and neurotoxicity in ischemic and hypoxic environment. Oxygen-glucose deprivation (OGD) was adopted to induce microglial activation and HT-22 neuron damage. Quantitative polymerase chain reaction (qRT-PCR) was taken to check miR-381-3p expression in OGD-elicited BV2 cells and HT-22 neurons. It transpired that miR-381-3p expression was lowered in BV2 cells and HT-22 cells elicited by OGD. miR-381-3p up-regulation remarkably hampered inflammatory mediator expression in BV2 cells induced by OGD and weakened HT22 neuron apoptosis. In vivo, miR-381-3p expression was abated in HI rats’ ischemic lesions, and miR-381-3p up-regulation could ameliorate inflammation and neuron apoptosis in their brain. C-C chemokine receptor type 2 (CCR2) was identified as the downstream target of miR-381-3p, and miR-381-3p suppressed the CCR2/NF-κB pathway to mitigate microglial activation and neurotoxicity. Therefore, we believed that miR-381-3p overexpression exerts anti-inflammation and anti-apoptosis in ischemic brain injury by targeting CCR2

Exosomal RNAs: Novel Potential Biomarkers for Diseases-A Review

Exosomes are a subset of nano-sized extracellular vesicles originating from endosomes. Exosomes mediate cell-to-cell communication with their cargos, which includes mRNAs, miRNAs, lncRNAs, and circRNAs. Exosomal RNAs have cell specificity and reflect the conditions of their donor cells. Notably, their detection in biofluids can be used as a diagnostic marker for various diseases. Exosomal RNAs are ideal biomarkers because their surrounding membranes confer stability and they are detectable in almost all biofluids, which helps to reduce trauma and avoid invasive examinations. However, knowledge of exosomal biomarkers remains scarce. The present review summarizes the biogenesis, secretion, and uptake of exosomes, the current researches exploring exosomal mRNAs, miRNAs, lncRNAs, and circRNAs as potential biomarkers for the diagnosis of human diseases, as well as recent techniques of exosome isolation.

Exosomal microRNAs as Potential Biomarkers and Therapeutic Agents for Acute Ischemic Stroke: New Expectations

The morbidity and mortality rates of ischemic stroke (IS) are very high, and IS constitutes one of the main causes of disability and death worldwide. The pathogenesis of ischemic stroke includes excitotoxicity, calcium overload, oxygen radical injury, inflammatory reactions, necrosis/apoptosis, destruction of the blood-brain barrier (BBB), and other pathologic processes. Recent studies have shown that exosomes are critical to the pathogenesis, diagnosis, and treatment of cerebral infarctions resulting from ischemic stroke; and there is growing interest in the role of exosomes and exosomal miRNAs in the diagnosis and treatment of IS. Exosomes from central nervous system cells can be found in cerebrospinal fluid and peripheral bodily fluids, and exosomal contents have been reported to change with disease occurrence. Exosomes are small membranous extracellular vesicles (EVs), 30–150 nm in diameter, that are released from the cell membrane into the depressions that arise from the membranes of multivesicular bodies. Exosomes carry lipids, proteins, mRNAs, and microRNAs (miRNAs) and transport information to target cells. This exosomal transfer of functional mRNAs/miRNAs and proteins ultimately affects transcription and translation within recipient cells. Exosomes are EVs with a double-membrane structure that protects them from ribonucleases in the blood, allowing exosomal miRNAs to be more stable and to avoid degradation. New evidence shows that exosomes derived from neural cells, endothelial cells, and various stem cells create a fertile environment that supports the proliferation and growth of neural cells and endothelial cells, inhibits apoptosis and inflammatory responses, and promotes angiogenesis. In the present review, we discuss how circulating exosomes—and exosomal miRNAs in particular—may provide novel strategies for the early diagnosis and treatment of ischemic stroke via their potential as non-invasive biomarkers and drug carriers.

Potential Role of Exosomes in Ischemic Stroke Treatment

Ischemic stroke is a life-threatening cerebral vascular disease and accounts for high disability and mortality worldwide. Currently, no efficient therapeutic strategies are available for promoting neurological recovery in clinical practice, except rehabilitation. The majority of neuroprotective drugs showed positive impact in pre-clinical studies but failed in clinical trials. Therefore, there is an urgent demand for new promising therapeutic approaches for ischemic stroke treatment. Emerging evidence suggests that exosomes mediate communication between cells in both physiological and pathological conditions. Exosomes have received extensive attention for therapy following a stroke, because of their unique characteristics, such as the ability to cross the blood brain–barrier, low immunogenicity, and low toxicity. An increasing number of studies have demonstrated positively neurorestorative effects of exosome-based therapy, which are largely mediated by the microRNA cargo. Herein, we review the current knowledge of exosomes, the relationships between exosomes and stroke, and the therapeutic effects of exosome-based treatments in neurovascular remodeling processes after stroke. Exosomes provide a viable and prospective treatment strategy for ischemic stroke patients.

Downregulation of miR-491-5p promotes neovascularization after traumatic brain injury

MicroRNA-491-5p (miR-491-5p) plays an important role in regulating cell proliferation and migration; however, the effect of miR-491-5p on neovascularization after traumatic brain injury remains poorly understood. In this study, a controlled cortical injury model in C57BL/6 mice and an oxygen-glucose deprivation model in microvascular endothelial cells derived from mouse brain were established to simulate traumatic brain injury in vivo and in vitro, respectively. In the in vivo model, quantitative real-time-polymerase chain reaction results showed that the expression of miR-491-5p increased or decreased following the intracerebroventricular injection of an miR-491-5p agomir or antagomir, respectively, and the expression of miR-491-5p decreased slightly after traumatic brain injury. To detect the neuroprotective effects of miR-491-p, neurological severity scores, Morris water maze test, laser speckle techniques, and immunofluorescence staining were assessed, and the results revealed that miR-491-5p downregulation alleviated neurological dysfunction, promoted the recovery of regional cerebral blood flow, increased the number of lectin-stained microvessels, and increased the survival of neurons after traumatic brain injury. During the in vitro experiments, the potential mechanism of miR-491-5p on neovascularization was explored through quantitative real-time-polymerase chain reaction, which showed that miR-491-5p expression increased or decreased in brain microvascular endothelial cells after transfection with an miR-491-5p mimic or inhibitor, respectively. Dual-luciferase reporter and western blot assays verified that metallothionein-2 was a target gene for miR-491-5p. Cell counting kit 8 (CCK-8) assay, flow cytometry, and 2?,7?-dichlorofluorescein diacetate (DCFH-DA) assay results confirmed that the downregulation of miR-491-5p increased brain microvascular endothelial cell viability, reduced cell apoptosis, and alleviated oxidative stress under oxygen-glucose deprivation conditions. Cell scratch assay, Transwell assay, tube formation assay, and western blot assay results demonstrated that miR-491-5p downregulation promoted the migration, proliferation, and tube formation of brain microvascular endothelial cells through a metallothionein-2-dependent hypoxia-inducible factor-1α/vascular endothelial growth factor pathway. These findings confirmed that miR-491-5p downregulation promotes neovascularization, restores cerebral blood flow, and improves the recovery of neurological function after traumatic brain injury. The mechanism may be mediated through a metallothionein-2-dependent hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway and the alleviation of oxidative stress. All procedures were approved by Ethics Committee of the First Affiliated Hospital of Chongqing Medical University, China (approval No. 2020-304) on June 22, 2020.

Cardioprotection of M2 macrophages-derived exosomal microRNA-24-3p/Tnfsf10 axis against myocardial injury after sepsis

OBJECTIVE

Some reports have suggested the involvement of microRNA-24-3p (miR-24-3p) in heart diseases. Here, the intention of this work was to unmask whether miR-24-3p from M2 macrophages-derived exosomes (M2-exo) could protect against myocardial injury after sepsis.

METHODS

Mice model of sepsis was induced by intraperitoneal injection of lipopolysaccharide (LPS). miR-24-3p and tumor necrosis factor superfamily member 10 (Tnfsf10) expression levels were measured in the myocardial tissue of septic mice. M2-exo were isolated, in which miR-24-3p expression was altered. Then, septic mice were alone or in combination injected with the miR-24-3p-modified M2-exo or siRNA of Tnfsf10. Subsequently, cardiac function, apoptosis and serum inflammatory response were examined.

RESULTS

miR-24-3p expression dropped while Tnfsf10 expression raised in the myocardial tissue of septic mice. M2-exo-derived miR-24-3p or deficiency of Tnfsf10 had cardioprotective effects on LPS-induced myocardial injury in mice through improving cardiac function and reducing cardiomyocyte apoptosis in the myocardial tissue and serum inflammation. A binding relation exhibited between miR-24-3p and Tnfsf10, and M2-exo-derived miR-24-3p alleviated LPS-induced myocardial injury by inhibiting Tnfsf10.

CONCLUSION

Up-regulating miR-24-3p from M2-exo imposes cardioprotection against myocardial injury after sepsis through reducing Tnfsf10 expression.

Exosomal microRNA-150-5p from bone marrow mesenchymal stromal cells mitigates cerebral ischemia/reperfusion injury via targeting toll-like receptor 5

MicroRNA (miR)-150-5p has been investigated in many studies, while the role of exosomal miR-150-5p from bone arrow mesenchymal stromal cells (BMSCs) on cerebral ischemia/reperfusion (I/R) injury is not fully explored. This research aims to probe the effects of exosomal miR-150-5p from BMSCs on cerebral I/R injury via regulating B-cell translocation gene 2 (TLR5). Bone marrow mesenchymal stem cell-derived exosomes (BMSCs-Exo) were isolated and identified. The middle cerebral artery occlusion (MCAO) rat model was established and treated by BMSCs-Exo. Then, functional assays were conducted to explore neurological function, pathological changes, neuron apoptosis and inflammatory factors in MCAO rats. miR-150-5p and TLR5 expression in rat brain tissues were detected. Then, gain and loss-function assays were conducted to determine the impact of exosomes, miR-150-5p and TLR5 on neurological function, pathological changes, neuron apoptosis and inflammatory factors of MCAO rats. The binding relation between miR-150-5p and TLR5 was validated. It was found that miR-150-5p expression was decreased while TLR5 level was augmented in MCAO rats. BMSCs-Exo could improve neurological function, pathological changes, decelerate neuron apoptosis and reduce inflammatory factors in MCAO rats. Enriched miR-150-5pcould enhance the protective effects of BMSCs-Exo on cerebral I/R injury. The elevated TLR5 reversed the impacts of elevated exosomal miR-150-5p on cerebral I/R injury. TLR5 was targeted by miR-150-5p. This research manifested that exosomal miR-150-5p from BMSCs exerts protective effects on cerebral I/R injury via repressing TLR5. This study provided novel therapeutic targets for the treatment of cerebral I/R injury.

Extracellular Vesicles: A New Paradigm for Cellular Communication in Perioperative Medicine, Critical Care, and Pain Management

Extracellular vesicles (EVs) play critical roles in many health and disease states, including ischemia, inflammation, and pain, which are major concerns in the perioperative period and in critically ill patients. EVs are functionally active, nanometer-sized, membrane-bound vesicles actively secreted by all cells. Cell signaling is essential to physiological and pathological processes, and EVs have recently emerged as key players in intercellular communication. Recent studies in EV biology have improved our mechanistic knowledge of the pathophysiological processes in perioperative and critical care patients. Studies also show promise in using EVs in novel diagnostic and therapeutic clinical applications. This review considers the current advances and gaps in knowledge of EVs in the areas of ischemia, inflammation, pain, and in organ systems that are most relevant to anesthesiology, perioperative medicine, critical care, and pain management. We expect the reader will better understand the relationship between EVs and perioperative and critical care pathophysiological states and their potential use as novel diagnostic and therapeutic modalities.

The role and therapeutic potential of exosomes in ischemic stroke

Ischemic stroke is a disease caused by insufficient blood and oxygen supply to the brain, which is mainly due to intracranial arterial stenosis and middle cerebral artery occlusion. Exosomes play an important role in cerebral ischemia. Nucleic acid substances such as miRNA, circRNA, lncRNA in exosomes can play communication roles and improve cerebral ischemia by regulating the development and regeneration of the nervous system, remodeling of blood vessels and inhibiting neuroinflammation. Furthermore, exosomes modulate stroke through various mechanisms, including improving neural communication, promoting the development of neuronal cells and myelin synapses, neurovascular unit remodeling and maintaining homeostasis of the nervous system. At the same time, exosomes are also a good carrier of bioactive substances, which can be modified and targeted to the lesion site. Here, we review the roles of exosomes in cerebral ischemia, and discuss the possible mechanisms and potentials of modification of exosomes for targeting stroke, providing a new idea for the prevention and treatment of cerebral ischemia.