Exosomes-carried microRNA-26b-5p regulates microglia M1 polarization after cerebral ischemia/reperfusion

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.

Targeting brain-peripheral immune responses for secondary brain injury after ischemic and hemorrhagic stroke

The notion that the central nervous system is an immunologically immune-exempt organ has changed over the past two decades, with increasing evidence of strong links and interactions between the central nervous system and the peripheral immune system, both in the healthy state and after ischemic and hemorrhagic stroke. Although primary injury after stroke is certainly important, the limited therapeutic efficacy, poor neurological prognosis and high mortality have led researchers to realize that secondary injury and damage may also play important roles in influencing long-term neurological prognosis and mortality and that the neuroinflammatory process in secondary injury is one of the most important influences on disease progression. Here, we summarize the interactions of the central nervous system with the peripheral immune system after ischemic and hemorrhagic stroke, in particular, how the central nervous system activates and recruits peripheral immune components, and we review recent advances in corresponding therapeutic approaches and clinical studies, emphasizing the importance of the role of the peripheral immune system in ischemic and hemorrhagic stroke.

Efficacy and safety of stem cells in the treatment of ischemic stroke: A meta-analysis

BACKGROUND

Stem cell therapy on ischemic stroke has long been studied using animal experiments. The efficacy and safety of this treatment in ischemic stroke patients remain uncertain.

METHODS

We searched for all clinical randomized controlled trials published before October 2023, on PubMed, EMBASE, and the Cochrane Library using predetermined search terms, and performed a meta-analysis of the efficacy of stem cell therapy in ischemic stroke patients.

RESULTS

13 studies that included 592 ischemic stroke patients were reviewed. The mRS (MD -0.32, 95% CI -0.64 to 0.00, I2 = 63%, P = .05), NIHSS (MD -1.63, 95% CI -2.69 to -0.57, I2 = 58%, P = .003), and BI (MD 14.22, 95% CI 3.95-24.48, I2 = 43%, P = .007) showed effective stem cell therapy. The mortality (OR 0.42, 95% CI 0.23-0.79, I2 = 0%, P = .007) showed improved prognosis and reduce mortality with stem cell therapy.

CONCLUSION

Stem cell therapy reduces mortality and improves the neurological prognosis of ischemic stroke patients. However, due to the different types of stem cells used and the limited data in the reported studies, the safety of clinical applications of stem cells in patients with ischemic stroke must be carefully evaluated. Future randomized controlled trials with large sample sizes from controlled cell sources are warranted to validate this finding.

Therapeutic potential of mesenchymal stem cells for cerebral small vessel disease

Cerebral small vessel disease (CSVD), as the most common, chronic and progressive vascular disease on the brain, is a serious neurological disease, whose pathogenesis remains unclear. The disease is a leading cause of stroke and vascular cognitive impairment and dementia, and contributes to about 20% of strokes, including 25% of ischemic strokes and 45% of dementias. Undoubtedly, the high incidence and poor prognosis of CSVD have brought a heavy economic and medical burden to society. The present treatment of CSVD focuses on the management of vascular risk factors. Although vascular risk factors may be important causes or accelerators of CSVD and should always be treated in accordance with best clinical practice, controlling risk factors alone could not curb the progression of CSVD brain injury. Therefore, developing safer and more effective treatment strategies for CSVD is urgently needed. Recently, mesenchymal stem cells (MSCs) therapy has become an emerging therapeutic modality for the treatment of central nervous system disease, given their paracrine properties and immunoregulatory. Herein, we discussed the therapeutic potential of MSCs for CSVD, aiming to enable clinicians and researchers to understand of recent progress and future directions in the field.

M2 macrophage-derived exosomal miR-26b-5p regulates macrophage polarization and chondrocyte hypertrophy by targeting TLR3 and COL10A1 to alleviate osteoarthritis

Osteoarthritis (OA) is one of the most prevalent chronic musculoskeletal diseases among the elderly population. In this study, macrophage-derived exosomes were isolated and identified. Exosomes were subjected to microRNA (miRNA) sequencing and bioinformatic analysis, and differentially expressed miRNAs were verified. miR-26b-5p target genes were confirmed through target-site mutation combined with a dual-luciferase reporter assay. The effects of miR-26b-5p on macrophage polarization and chondrocyte hypertrophy were assessed in vitro. miR-26b-5p agomir was applied to mice with OA induced by anterior cruciate ligament transection (ACLT). The therapeutic effects of miR-26b-5p were evaluated via pain behavior experiments and histological observations. In vitro, miR-26b-5p repolarized M1 macrophages to an anti-inflammatory M2 type by targeting the TLR3 signaling pathway. miR-26b-5p could target COL10A1, further inhibiting chondrocyte hypertrophy induced by M1 macrophage-conditioned medium (M1-CM). In vivo, miR-26b-5p agomir ameliorated gait abnormalities and mechanical allodynia in OA mice. miR-26b-5p treatment attenuated synovitis and cartilage degeneration, thereby delaying OA progression. In conclusion, M2 macrophage-derived exosomal miR-26b-5p could protect articular cartilage and ameliorate gait abnormalities in OA mice by targeting TLR3 and COL10A1. miR-26b-5p further affected macrophage polarization and chondrocyte hypertrophy. Thus, this exosomal miR-26b-5p-based strategy might be a potential method for OA treatment.

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.

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.

Exosomes as cutting-edge therapeutics in various biomedical applications: An update on engineering, delivery, and preclinical studies

Exosomes are cell-derived nanovesicles, circulating in different body fluids, and acting as an intercellular mechanism. They can be purified from culture media of different cell types and carry an enriched content of various protein and nucleic acid molecules originating from their parental cells. It was indicated that the exosomal cargo can mediate immune responses via many signaling pathways. Over recent years, the therapeutic effects of various exosome types were broadly investigated in many preclinical studies. Herein, we present an update on recent preclinical studies on exosomes as therapeutic and/or delivery agents for various applications. The exosome origin, structural modifications, natural or loaded active ingredients, size, and research outcomes were summarized for various diseases. Overall, the present article provides an overview of the latest exosome research interests and developments to clear the way for the clinical study design and application.

Potential regulatory effects of stem cell exosomes on inflammatory response in ischemic stroke treatment

The high incidence and disability rates of stroke pose a heavy burden on society. Inflammation is a significant pathological reaction that occurs after an ischemic stroke. Currently, therapeutic methods, except for intravenous thrombolysis and vascular thrombectomy, have limited time windows. Mesenchymal stem cells (MSCs) can migrate, differentiate, and inhibit inflammatory immune responses. Exosomes (Exos), which are secretory vesicles, have the characteristics of the cells from which they are derived, making them attractive targets for research in recent years. MSC-derived exosomes can attenuate the inflammatory response caused by cerebral stroke by modulating damage-associated molecular patterns. In this review, research on the inflammatory response mechanisms associated with Exos therapy after an ischemic injury is discussed to provide a new approach to clinical treatment.

miRNA-Guided Regulation of Mesenchymal Stem Cells Derived from the Umbilical Cord: Paving the Way for Stem-Cell Based Regeneration and Therapy

The human body is an abundant source of multipotent cells primed with unique properties that can be exploited in a multitude of applications and interventions. Mesenchymal stem cells (MSCs) represent a heterogenous population of undifferentiated cells programmed to self-renew and, depending on their origin, differentiate into distinct lineages. Alongside their proven ability to transmigrate toward inflammation sites, the secretion of various factors that participate in tissue regeneration and their immunoregulatory function render MSCs attractive candidates for use in the cytotherapy of a wide spectrum of diseases and conditions, as well as in different aspects of regenerative medicine. In particular, MSCs that can be found in fetal, perinatal, or neonatal tissues possess additional capabilities, including predominant proliferation potential, increased responsiveness to environmental stimuli, and hypoimmunogenicity. Since microRNA (miRNA)-guided gene regulation governs multiple cellular functions, miRNAs are increasingly being studied in the context of driving the differentiation process of MSCs. In the present review, we explore the mechanisms of miRNA-directed differentiation of MSCs, with a special focus on umbilical cord-derived mesenchymal stem cells (UCMSCs), and we identify the most relevant miRNAs and miRNA sets and signatures. Overall, we discuss the potent exploitations of miRNA-driven multi-lineage differentiation and regulation of UCMSCs in regenerative and therapeutic protocols against a range of diseases and/or injuries that will achieve a meaningful clinical impact through maximizing treatment success rates, while lacking severe adverse events.

Mesenchymal stem cell-derived exosomes in cardiovascular and cerebrovascular diseases: From mechanisms to therapy

Cardiovascular and cerebrovascular diseases (CVDs) remain an intractable problem and have high morbidity and mortality worldwide, as well as substantial health and economic burdens, representing an urgent clinical need. In recent years, the focus of research has shifted from the use of mesenchymal stem cells (MSCs) for transplantation to the use of their secretory exosomes (MSC-exosomes) for the treatment of numerous CVDs, including atherosclerosis, myocardial infarction (MI), heart failure (HF), ischemia/reperfusion (I/R), aneurysm, and stroke. MSCs are pluripotent stem cells with multiple differentiation pathways that exert pleiotropic effects by producing soluble factors, the most effective components of which are exosomes. MSC-exosomes are considered to be an excellent and promising cell-free therapy for CVDs due to their higher circulating stability, improved biocompatibility, reduced toxicity, and immunogenicity. In addition, exosomes play critical roles in repairing CVDs by inhibiting apoptosis, regulating inflammation, ameliorating cardiac remodeling, and promoting angiogenesis. Herein, we describe knowledge about the biological characteristics of MSC-exosomes, investigate the mechanism by which MSC-exosomes mediate therapeutic repair, and summarize recent advances in the efficacy of MSC-exosomes in CVDs, with a view toward future clinical applications.

Immunomodulation: The next target of mesenchymal stem cell-derived exosomes in the context of ischemic stroke

Ischemic stroke (IS) is the most prevalent form of brain disease, characterized by high morbidity, disability, and mortality. However, there is still a lack of ideal prevention and treatment measures in clinical practice. Notably, the transplantation therapy of mesenchymal stem cells (MSCs) has been a hot research topic in stroke. Nevertheless, there are risks associated with this cell therapy, including tumor formation, coagulation dysfunction, and vascular occlusion. Also, a growing number of studies suggest that the therapeutic effect after transplantation of MSCs is mainly attributed to MSC-derived exosomes (MSC-Exos). And this cell-free mediated therapy appears to circumvent many risks and difficulties when compared to cell therapy, and it may be the most promising new strategy for treating stroke as stem cell replacement therapy. Studies suggest that suppressing inflammation via modulation of the immune response is an additional treatment option for IS. Intriguingly, MSC-Exos mediates the inflammatory immune response following IS by modulating the central nervous system, the peripheral immune system, and immunomodulatory molecules, thereby promoting neurofunctional recovery after stroke. Thus, this paper reviews the role, potential mechanisms, and therapeutic potential of MSC-Exos in post-IS inflammation in order to identify new research targets.

Modulatory effects of mesenchymal stem cells on microglia in ischemic stroke

Ischemic stroke accounts for 70-80% of all stroke cases. Immunity plays an important role in the pathophysiology of ischemic stroke. Microglia are the first line of defense in the central nervous system. Microglial functions are largely dependent on their pro-inflammatory (M1-like) or anti-inflammatory (M2-like) phenotype. Modulating neuroinflammation via targeting microglia polarization toward anti-inflammatory phenotype might be a novel treatment for ischemic stroke. Mesenchymal stem cells (MSC) and MSC-derived extracellular vesicles (MSC-EVs) have been demonstrated to modulate microglia activation and phenotype polarization. In this review, we summarize the physiological characteristics and functions of microglia in the healthy brain, the activation and polarization of microglia in stroke brain, the effects of MSC/MSC-EVs on the activation of MSC in vitro and in vivo, and possible underlying mechanisms, providing evidence for a possible novel therapeutics for the treatment of ischemic stroke.

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.

The Key Drivers of Brain Injury by Systemic Inflammatory Responses after Sepsis: Microglia and Neuroinflammation

Sepsis is a leading cause of intensive care unit admission and death worldwide. Most surviving patients show acute or chronic mental disorders, which are known as sepsis-associated encephalopathy (SAE). Although accumulating studies in the past two decades focused on the pathogenesis of SAE, a systematic review of retrospective studies which exclusively focuses on the inflammatory mechanisms of SAE has been lacking yet. This review summarizes the recent advance in the field of neuroinflammation and sheds light on the activation of microglia in SAE. Activation of microglia predominates neuroinflammation. As the gene expression profile changes, microglia show heterogeneous characterizations throughout all stages of SAE. Here, we summarize the systemic inflammation following sepsis and also the relationship of microglial diversity and neuroinflammation. Moreover, a collection of neuroinflammation-related dysfunction has also been reviewed to illustrate the possible mechanisms for SAE. In addition, promising pharmacological or non-pharmacological therapeutic strategies, especially those which target neuroinflammation or microglia, are also concluded in the final part of this review. Collectively, clarification of the vital relationship between neuroinflammation and SAE-related mental disorders would significantly improve our understanding of the pathophysiological mechanisms in SAE and therefore provide potential targets for therapies of SAE aimed at inhibiting neuroinflammation.

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.

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.

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.

A systematic review of the research progress of non-coding RNA in neuroinflammation and immune regulation in cerebral infarction/ischemia-reperfusion injury

Cerebral infarction/ischemia-reperfusion injury is currently the disease with the highest mortality and disability rate of cardiovascular disease. Current studies have shown that nerve cells die of ischemia several hours after ischemic stroke, which activates the innate immune response in the brain, promotes the production of neurotoxic substances such as inflammatory cytokines, chemokines, reactive oxygen species and − nitrogen oxide, and mediates the destruction of blood-brain barrier and the occurrence of a series of inflammatory cascade reactions. Meanwhile, the expression of adhesion molecules in cerebral vascular endothelial cells increased, and immune inflammatory cells such as polymorphonuclear neutrophils, lymphocytes and mononuclear macrophages passed through vascular endothelial cells and entered the brain tissue. These cells recognize antigens exposed by the central nervous system in the brain, activate adaptive immune responses, and further mediate secondary neuronal damage, aggravating neurological deficits. In order to reduce the above-mentioned damage, the body induces peripheral immunosuppressive responses through negative feedback, which increases the incidence of post-stroke infection. This process is accompanied by changes in the immune status of the ischemic brain tissue in local and systemic systems. A growing number of studies implicate noncoding RNAs (ncRNAs) as novel epigenetic regulatory elements in the dysfunction of various cell subsets in the neurovascular unit after cerebral infarction/ischemia-reperfusion injury. In particular, recent studies have revealed advances in ncRNA biology that greatly expand the understanding of epigenetic regulation of immune responses and inflammation after cerebral infarction/ischemia-reperfusion injury. Identification of aberrant expression patterns and associated biological effects of ncRNAs in patients revealed their potential as novel biomarkers and therapeutic targets for cerebral infarction/ischemia-reperfusion injury. Therefore, this review systematically presents recent studies on the involvement of ncRNAs in cerebral infarction/ischemia-reperfusion injury and neuroimmune inflammatory cascades, and elucidates the functions and mechanisms of cerebral infarction/ischemia-reperfusion-related ncRNAs, providing new opportunities for the discovery of disease biomarkers and targeted therapy. Furthermore, this review introduces clustered regularly interspaced short palindromic repeats (CRISPR)-Display as a possible transformative tool for studying lncRNAs. In the future, ncRNA is expected to be used as a target for diagnosing cerebral infarction/ischemia-reperfusion injury, judging its prognosis and treatment, thereby significantly improving the prognosis of patients.

Inhibition of Cerebral Ischemia/Reperfusion Injury by MSCs-Derived Small Extracellular Vesicles in Rodent Models: A Systematic Review and Meta-Analysis

Small extracellular vesicles (sEVs) secreted by mesenchymal stem cells (MSCs) have shown great therapeutic potential in cerebral ischemia-reperfusion injury (CIRI). In this study, we firstly performed a systematic review to evaluate the efficacy of MSCs-derived sEV for experimental cerebral ischemia/reperfusion injury. 24 studies were identified by searching 8 databases from January 2012 to August 2022. The methodological quality was assessed by using the SYRCLE ‘s risk of bias tool for animal studies. All the data were analyzed using RevMan 5.3 software. As a result, the score of study quality ranged from 3 to 9 in a total of ten points. Meta-analyses showed that MSCs-derived sEVs could effectively alleviate neurological impairment scores, reduced the volume of cerebral infarction and brain water content, and attenuated neuronal apoptosis. Additionally, the possible mechanisms of MSCs-derived sEVs for attenuating neuronal apoptosis were inhibiting microglia-mediated neuroinflammation. Thus, MSCs-derived sEVs might be regarded as a novel insight for cerebral ischemic stroke. However, further mechanistic studies, therapeutic safety, and clinical trials are required. Systematic review registration. PROSPERO CRD42022312227.

Extracellular vesicles and particles impact the systemic landscape of cancer

Intercellular cross talk between cancer cells and stromal and immune cells is essential for tumor progression and metastasis. Extracellular vesicles and particles (EVPs) are a heterogeneous class of secreted messengers that carry bioactive molecules and that have been shown to be crucial for this cell-cell communication. Here, we highlight the multifaceted roles of EVPs in cancer. Functionally, transfer of EVP cargo between cells influences tumor cell growth and invasion, alters immune cell composition and function, and contributes to stromal cell activation. These EVP-mediated changes impact local tumor progression, foster cultivation of pre-metastatic niches at distant organ-specific sites, and mediate systemic effects of cancer. Furthermore, we discuss how exploiting the highly selective enrichment of molecules within EVPs has profound implications for advancing diagnostic and prognostic biomarker development and for improving therapy delivery in cancer patients. Altogether, these investigations into the role of EVPs in cancer have led to discoveries that hold great promise for improving cancer patient care and outcome.

LncRNA, an Emerging Approach for Neurological Diseases Treatment by Regulating Microglia Polarization

Neurological disorders cause untold human disability and death each year. For most neurological disorders, the efficacy of their primary treatment strategies remains suboptimal. Microglia are associated with the development and progression of multiple neurological disorders. Targeting the regulation of microglia polarization has emerged as an important therapeutic strategy for neurological disorders. Their pro-inflammatory (M1)/anti-inflammatory (M2) phenotype microglia are closely associated with neuronal apoptosis, synaptic plasticity, blood-brain barrier integrity, resistance to iron death, and astrocyte regulation. LncRNA, a recently extensively studied non-coding transcript of over 200 nucleotides, has shown great value to intervene in microglia polarization. It can often participate in gene regulation of microglia by directly regulating transcription or sponging downstream miRNAs, for example. Through proper regulation, microglia can exert neuroprotective effects, reduce neurological damage and improve the prognosis of many neurological diseases. This paper reviews the progress of research linking lncRNAs to microglia polarization and neurological diseases.

Exosomes Derived From Mesenchymal Stem Cells: Novel Effects in the Treatment of Ischemic Stroke

Ischemic stroke is defined as an infarction in the brain, caused by impaired cerebral blood supply, leading to local brain tissue ischemia, hypoxic necrosis, and corresponding neurological deficits. At present, revascularization strategies in patients with acute ischemic stroke include intravenous thrombolysis and mechanical endovascular treatment. However, due to the short treatment time window (<4.5 h) and method restrictions, clinical research is focused on new methods to treat ischemic stroke. Exosomes are nano-sized biovesicles produced in the endosomal compartment of most eukaryotic cells, containing DNA, complex RNA, and protein (30-150 nm). They are released into surrounding extracellular fluid upon fusion between multivesicular bodies and the plasma membrane. Exosomes have the characteristics of low immunogenicity, good innate stability, high transmission efficiency, and the ability to cross the blood-brain barrier, making them potential therapeutic modalities for the treatment of ischemic stroke. The seed sequence of miRNA secreted by exosomes is base-paired with complementary mRNA to improve the microenvironment of ischemic tissue, thereby regulating downstream signal transduction activities. With exosome research still in the theoretical and experimental stages, this review aims to shed light on the potential of exosomes derived from mesenchymal stem cells in the treatment of ischemic stroke.

Microglia Polarization: A Novel Target of Exosome for Stroke Treatment

The vast majority of cells in the human body are capable of secreting exosomes. Exosomes have become an important vehicle for signaling between cells. Exosomes secreted by different cells have some of the structural and functional properties of that cell and thus have different regulatory functions. A large number of recent experimental studies have shown that exosomes from different sources have different regulatory effects on stroke, and the mechanisms still need to be elucidated. Microglia are core members of central intrinsic immune regulatory cells, which play an important regulatory role in the pathogenesis and progression of stroke. M1 microglia cause neuroinflammation and induce neurotoxic effects, while M2 microglia inhibit neuroinflammation and promote neurogenesis, thus exerting a series of neuroprotective effects. It was found that there is a close link between exosomes and microglia polarization, and that exosome inclusions such as microRNAs play a regulatory role in the M1/M2 polarization of microglia. This research reviews the role of exosomes in the regulation of microglia polarization and reveals their potential value in stroke treatment.

MicroRNA-26b-5p Targets DAPK1 to Reduce Intestinal Ischemia/Reperfusion Injury via Inhibition of Intestinal Mucosal Cell Apoptosis

BACKGROUND

Emerging evidence has suggested that miRNAs are important regulators of intestinal I/R injury, but their function in this context remains elusive.

AIMS

To evaluate the role of miR-26b-5p in intestinal I/R injury.

METHODS

We utilized in vivo murine models of intestinal I/R and in vitro Mode-K cell-based models of oxygen and glucose deprivation/reperfusion (OGD/R) to examine the function of miR-26b-5p in intestinal I/R injury. The expression of miR-26b-5p in intestinal mucosa and Mode-K cell was detected by RT-PCR. HE staining and Chiu's score were used to evaluate intestinal mucosa injury severity. Apoptosis was detected by TUNEL stain, flow cytometry, and western blot. TargetScan and StarBase prediction algorithms were applied to predict putative target genes of miR-26b-5p and validated by luciferase reporter analyses.

RESULTS

We found that the expression of miR-26b-5p in intestinal mucosa was markedly decreased during I/R injury. We additionally found miR-26b-5p overexpression to markedly disrupt intestinal I/R- or OGD/R-induced injury in vivo and in vitro, whereas inhibiting this miRNA had an adverse impact and resulted in increased intestinal tissue injury and Mode-K cell damage. From a mechanistic perspective, miR-26b-5p was predicted to target DAPK1, which was related to cellular apoptosis. Luciferase reporter assay results confirmed that miR-26b-5p directly targets DAPK1 in Mode-K cells, thereby suppressing OGD/R-induced cell apoptosis.

CONCLUSION

Our findings show that miR-26b-5p may prevent intestinal I/R injury via targeting DAPK1 and inhibiting intestinal mucosal cell apoptosis, suggesting that this miRNA may be a viable target for the treatment of intestinal I/R injury.

Epigenetic Regulations of Microglia/Macrophage Polarization in Ischemic Stroke

Ischemic stroke is one of the leading causes of death and disability worldwide. Microglia/macrophages (MMs)-mediated neuroinflammation contributes significantly to the pathological process of ischemic brain injury. Microglia, serving as resident innate immune cells in the central nervous system, undergo pro-inflammatory phenotype or anti-inflammatory phenotype in response to the microenvironmental changes after cerebral ischemia. Emerging evidence suggests that epigenetics modifications, reversible modifications of the phenotype without changing the DNA sequence, could play a pivotal role in regulation of MM polarization. However, the knowledge of the mechanism of epigenetic regulations of MM polarization after cerebral ischemia is still limited. In this review, we present the recent advances in the mechanisms of epigenetics involved in regulating MM polarization, including histone modification, non-coding RNA, and DNA methylation. In addition, we discuss the potential of epigenetic-mediated MM polarization as diagnostic and therapeutic targets for ischemic stroke. It is valuable to identify the underlying mechanisms between epigenetics and MM polarization, which may provide a promising treatment strategy for neuronal damage after cerebral ischemia.

MiR-26b-5p-modified hUB-MSCs derived exosomes attenuate early brain injury during subarachnoid hemorrhage via MAT2A-mediated the p38 MAPK/STAT3 signaling pathway

Early brain injury (EBI) is a major cause of adverse outcomes following subarachnoid hemorrhage (SAH). There is evidence that mesenchymal stem cells (MSCs) - derived exosomes are involved in the repair of SAH. Exosomes were extracted from human umbilical cord mesenchymal stem cells (hubMSCs) and identified. OxyHb treated PC12 cells were transfected with exosomes alone or together with miR-26b-5p inhibitor. Hub-MSCs derived exosomes promote cell proliferation, inhibit apoptosis and reduce inflammatory mediator expression. Transfection of miR-26b-5p inhibitor abolished the promoting effect of exosomes on the proliferation of PC12 cells, as well as the inhibitory effect on cell apoptosis. In addition, methionine adenosyltransferase II alpha (MAT2A) was one target gene of miR-26b-5p. OxyHb treated PC12 cells were transfected with exosomes alone or together with pcDNA-MAT2A and observed that the promoting effect of exosomes on PC12 cell proliferation was abolished by pcDNA-MAT2A, which was the same as the effect of miR-26b-5p inhibitor. OxyHb treated PC cells incubated with exosomes were transfected with miR-26b-5p inhibitor alone or together with si-MAT2A, respectively, and it was observed that exosomes decreased the phosphorylation levels of p38 MAPK and STAT3 proteins, inhibited cell apoptosis and inflammatory mediator expression, and miR-26b-5p inhibitor abrogated the effects of exosomes, while transfection of si-MAT2A reversed the effects of miR-26b-5p inhibitor. Moreover, injection of miR-26b-5p inhibitor resulted in increased MAT2A and pathway protein expression, increased inflammatory mediators, and aggravated neurological symptoms in the brain tissues of SAH rats.

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.

Mesenchymal stem cell-derived exosomal miR-143-3p suppresses myocardial ischemia-reperfusion injury by regulating autophagy

AIMS

Myocardial ischemia-reperfusion (I/R) injury is considered as a major obstacle of myocardial perfusion to save acute myocardial infarction, and causes a serious threat to human health. An extensive body of evidence has unveiled that mesenchymal stem cells (MSCs) as adult stem cells play a vital role in the field of damaged myocardial regeneration and repair. However, the biological role of MSCs derived-exosomes in the protection of myocardial I/R injury has not been elucidated.

MAIN METHODS

In this study, we isolated and characterized MSCs from the bone marrow of rats femur and tibia. H9c2 cells were administrated to established the cellular hypoxia-reoxygenation (H/R) model, and co-cultured with MSCs and MSCs-derived exosomes.

KEY FINDINGS

Functional experiments revealed that MSCs and MSCs-derived exosomes inhibited H/R-induced cell apoptosis and cell autophagy. Interestingly, rapamycin as an activator of autophagy reversed the positive effects of MSCs-derived exosomes, while 3-methyladenine (3-MA) as autophagy inhibitor further promoted the effects of MSCs-derived exosomes, indicating MSCs exerted its function on H/R injury by mediating autophagy. Subsequently, we found that CHK2-Beclin2 pathway participated in H/R-induced autophagy. Mechanistically, miR-143-3p directly targeted CHK2 and negatively regulated CHK2 expression. Moreover, repression of exosomal miR-143-3p promoted H/R-induced autophagy via CHK2-Beclin2 pathway. Consistent with the results of in vitro experiments, in vivo experiments confirmed that exosomal miR-143-3p effectively reduced cell apoptosis by regulating autophagy via CHK2-Beclin2 pathway.

SIGNIFICANCE

Collectively, our results indicated that MSCs-derived exosomal miR-143-3p might represent a promising option for the treatment of I/R injury.

Modulating poststroke inflammatory mechanisms: Novel aspects of mesenchymal stem cells, extracellular vesicles and microglia

Inflammation plays an important role in the pathological process of ischemic stroke, and systemic inflammation affects patient prognosis. As resident immune cells in the brain, microglia are significantly involved in immune defense and tissue repair under various pathological conditions, including cerebral ischemia. Although the differentiation of M1 and M2 microglia is certainly oversimplified, changing the activation state of microglia appears to be an intriguing therapeutic strategy for cerebral ischemia. Recent evidence indicates that both mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (EVs) regulate inflammation and modify tissue repair under preclinical stroke conditions. However, the precise mechanisms of these signaling pathways, especially in the context of the mutual interaction between MSCs or MSC-derived EVs and resident microglia, have not been sufficiently unveiled. Hence, this review summarizes the state-of-the-art knowledge on MSC- and MSC-EV-mediated regulation of microglial activity under ischemic stroke conditions with respect to various signaling pathways, including cytokines, neurotrophic factors, transcription factors, and microRNAs.

MSCs‑derived exosomes attenuate ischemia-reperfusion brain injury and inhibit microglia apoptosis might via exosomal miR-26a-5p mediated suppression of CDK6

Background

This study aimed to explore the role of mesenchymal stromal cells (MSCs)-derived exosomes (MSCs-Exo) in the cerebral ischemia–reperfusion (I/R) injury.

Methods

Exosomes were isolated from MSCs of adult C57BL/6J mice by the gradient centrifugation method. The expression of miR-26a-5p and CDK6 in MSCs-Exo and mice brain tissues were evaluated by qRT-PCR and western blot. miR-26a-5p mimics and miR-NC were transfected into MSCs, and exosomes were isolated from the MSCs stably expressing miR-26a-5p. Then MSCs-Exo-miR-26a-5p mimics or MSCs-Exo-miR-NC was injected into mice through the tail vein, or added into medium to stimulate BV-2 cells. Cell viability was evaluated by CCK-8 assay. Cell apoptosis was detected by flow cytometry. The apoptosis in brain tissues was evaluated by TUNEL staining assay. Bioinformatics analysis and luciferase reporter assay were performed to determine the binding relationship between miR-26a-5p and CDK6.

Results

miR-26a-5p was downregulated and CDK6 was upregulated in MSCs-Exo of MCAO-mice and OGD-induced MSCs. MSCs-Exo-miR-26a-5p mimics significantly reduced cell apoptosis of OGD-injured BV-2 cells. MSCs-Exo-miR-26a-5p mimics significantly reduced the infarct volume of MCAO-induced mice. Luciferase reporter assay revealed that CDK-6 was a target of miR-26a-5p. In addition, MSCs-Exo-miR-26a-5p mimics significantly decreased the expression of CDK6 in both OGD-induced BV-2 cells and the brain tissues of MCAO-treated mice.

Conclusion

Our results indicated that MSCs‑Exo attenuated I/R injury in mice by inhibiting microglia apoptosis might via exosomal miR-26a-5p mediated suppression of CDK6. Our study shed light on the application of MSC-Exo as a potential therapeutic tool for cerebral I/R injury.

Neuroinflammation: The next target of exosomal microRNAs derived from mesenchymal stem cells in the context of neurological disorders

Among different types of mechanisms involved in neurological disorders, neuroinflammation links initial insults to secondary injuries and triggers some chronic outcomes, for example, neurodegenerative disorders. Thus, anti-inflammatory substances can be targeted as a novel therapeutic option for translational and clinical research to improve brain disease outcomes. In this review, we propose to introduce a new insight into the anti-inflammatory effects of mesenchymal stem cells (MSCs) as the most frequent source for stem cell therapy in neurological diseases. Our insight incorporates a bystander effect of these stem cells in modulating inflammation and microglia/macrophage polarization through exosomes. Exosomes are nano-sized membrane vesicles that carry cell-specific constituents, including protein, lipid, DNA, and RNA. microRNAs (miRNAs) have recently been detected in exosomes that can be taken up by other cells and affect the behavior of recipient cells. In this article, we outline and highlight the potential use of exosomal miRNAs derived from MSCs for inflammatory pathways in the context of neurological disorders. Furthermore, we suggest that focusing on exosomal miRNAs derived from MSCs in the course of neuroinflammatory pathways in the future could reveal their functions for diverse neurological diseases, including brain injuries and neurodegenerative diseases. It is hoped that this study will contribute to a deep understanding of stem cell bystander effects through exosomal miRNAs.

Bone marrow mesenchymal stem cells-secreted exosomal H19 modulates lipopolysaccharides-stimulated microglial M1/M2 polarization and alleviates inflammation-mediated neurotoxicity

Neuroinflammation is the most common cause of neurological diseases. Exosomes derived from mesenchymal stem cells (MSCs-exos) have been reported to reduce inflammation and neuronal injury. Its underlying mechanism remains poorly unknown. In this study, identification of bone marrow MSCs-derived exosomes (BMSCs-exos) was conducted by nanosight tracking analysis, transmission electron microscope, and western blot assay. Enzyme-linked immunosorbent (ELISA) was used to analyze microglial M1/M2 polarization and detect levels of inflammatory factors. Cell viability was determined by Cell Counting Kit (CCK)-8 assay. Cell apoptosis was assessed by flow cytometry, caspase-3 activity assay, and DNA fragmentation assay. Quantitative real-time polymerase chain reaction was used to detect gene expression. Luciferase reporter and RNA pull-down assays were exploited to validate the interaction between genes. BMSCs-exos promoted M2 polarization while inhibited M1 polarization in LPS-stimulated BV-2 cells. BMSCs-exos inhibited the secretion of interleukin (IL)-1β, IL-6, and TNF-α, while increased the levels of IL-10. BMSCs-exos resisted the cytotoxicity and apoptosis induced by LPS in HT22 cells. BMSCs-exosomal long noncoding RNA (lncRNA) H19 enhanced the anti-inflammatory ability of BMSCs-exos in BV-2 microglia following LPS stimulation, and strengthened the neuroprotective effect of BMSCs-exos on HT22 cells in the presence of LPS. Moreover, H19 functioned as a sponge for miR-29b-3p. miR-29b-3p mimics abolished the effects of BMSCs-exosomal H19 on M1/M2 polarization and inflammation in LPS-stimulated BV-2 cells. The neuroprotective function of BMSCs-exosomal H19 was attenuated by miR-29b-3p mimics in LPS-stimulated HT22 cells. BMSCs-exosomal H19 modulates LPS-stimulated microglial M1/M2 polarization and alleviates inflammation-mediated neurotoxicity by sponging miR-29b-3p.

Oxidative Stress, Inflammation, and Autophagy: Potential Targets of Mesenchymal Stem Cells-Based Therapies in Ischemic Stroke

Ischemic stroke is a leading cause of death worldwide; currently available treatment approaches for ischemic stroke are to restore blood flow, which reduce disability but are time limited. The interruption of blood flow in ischemic stroke contributes to intricate pathophysiological processes. Oxidative stress and inflammatory activity are two early events in the cascade of cerebral ischemic injury. These two factors are reciprocal causation and directly trigger the development of autophagy. Appropriate autophagy activity contributes to brain recovery by reducing oxidative stress and inflammatory activity, while autophagy dysfunction aggravates cerebral injury. Abundant evidence demonstrates the beneficial impact of mesenchymal stem cells (MSCs) and secretome on cerebral ischemic injury. MSCs reduce oxidative stress through suppressing reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation and transferring healthy mitochondria to damaged cells. Meanwhile, MSCs exert anti-inflammation properties by the production of cytokines and extracellular vesicles, inhibiting proinflammatory cytokines and inflammatory cells activation, suppressing pyroptosis, and alleviating blood–brain barrier leakage. Additionally, MSCs regulation of autophagy imbalances gives rise to neuroprotection against cerebral ischemic injury. Altogether, MSCs have been a promising candidate for the treatment of ischemic stroke due to their pleiotropic effect.

Receptors, Channel Proteins, and Enzymes Involved in Microglia-mediated Neuroinflammation and Treatments by Targeting Microglia in Ischemic Stroke

Stroke is the largest contributor to global neurological disability-adjusted life-years, posing a huge economic and social burden to the world. Though pharmacological recanalization with recombinant tissue plasminogen activator and mechanical thrombectomy have greatly improved the prognosis of patients with ischemic stroke, clinically, there is still no effective treatment for the secondary injury caused by cerebral ischemia. In recent years, more and more evidences show that neuroinflammation plays a pivotal role in the pathogenesis and progression of ischemic cerebral injury. Microglia are brain resident innate immune cells and act the role peripheral macrophages. They play critical roles in mediating neuroinflammation after ischemic stroke. Microglia-mediated neuroinflammation is not an isolated process and has complex relationships with other pathophysiological processes as oxidative/nitrative stress, excitotoxicity, necrosis, apoptosis, pyroptosis, autophagy, and adaptive immune response. Upon activation, microglia differentially express various receptors, channel proteins, and enzymes involved in promoting or inhibiting the inflammatory processes, making them the targets of intervention for ischemic stroke. To inhibit microglia-related neuroinflammation and promote neurological recovery after ischemic stroke, numerous biochemical agents, cellular therapies, and physical methods have been demonstrated to have therapeutic potentials. Though accumulating experimental evidences have demonstrated that targeting microglia is a promising approach in the treatment of ischemic stroke, the clinical progress is slow. Till now, no clinical study could provide convincing evidence that any biochemical or physical therapies could exert neuroprotective effect by specifically targeting microglia following ischemic stroke.

MicroRNA-26b-5p alleviates cerebral ischemia-reperfusion injury in rats via inhibiting the N-myc/PTEN axis by downregulating KLF10 expression

MicroRNAs plays important role in cerebral ischemia-reperfusion (CIR). However, the role of miR-26b-5p in CIR injury remains unclear. PC12 cells were treated with oxygen-glucose deprivation (OGD) for 0 h, 2 h, 4 h, 6 h, and then reoxygenated for 24 h to construct an in vitro I/R model. Then, miR-26b-5p mimic, small interfering RNA of KLF10 and KLF10 overexpression plasmid were transfected into cells respectively for mechanism study. Our results showed that miR-26b-5p was downregulated in OGD/R-induced PC12 cells. After overexpression of miR-26b-5p, cell proliferation ability was enhanced, apoptosis, ROS and inflammatory mediators were inhibited. Bioinformatics analysis indicated that miR-26b-5p was directly bound to the 3' UTR of KLF10, and downregulated the expression of KLF10. KLF10 was upregulated in OGD/R cells, and transfection with si-KLF10 promoted cell proliferation and reduced apoptosis, NO concentration and inflammatory factor secretion. Moreover, pcDNA-KLF10 reversed the inhibitory effects of miR-26b-5p mimic on apoptosis, NO content and inflammatory factor secretion, as well as the downregulation of N-myc and PTEN expression. Meanwhile, I/R rat models were constructed and divided into sham operation group (femoral artery isolation only), model group (middle cerebral artery occlusion model of rats was prepared by thread embolization), treatment group (200 µL of miR-26b-5p mimic was injected into the brain of model rats). We observed that the infarct size of brain tissue was reduced, KLF10 expression was downregulated, and apoptosis and inflammatory response were reduced. These results suggest that miR-26b-5p had protective effects on CIRI and it may be a potential treatment target.

Neurovascular Unit: A critical role in ischemic stroke

Ischemic stroke (IS), a common cerebrovascular disease, results from a sudden blockage of a blood vessel in the brain, thereby restricting blood supply to the area in question, and making a significantly negative impact on human health. Unfortunately, current treatments, that are mainly based on a recanalization of occluded blood vessels, are insufficient or inaccessible to many stroke patients. Recently, the profound influence of the neurovascular unit (NVU) on recanalization and the prognosis of IS have become better understood; in‐depth studies of the NVU have also provided novel approaches for IS treatment. In this article, we review the intimate connections between the changes in the NVU and IS outcomes, and discuss possible new management strategies having practical significance to IS. We discuss the concept of the NVU, as well as its roles in IS blood‐brain barrier regulation, cell preservation, inflammatory immune response, and neurovascular repair. Besides, we also summarize the influence of noncoding RNAs in NVU, and IS therapies targeting the NVU. We conclude that both the pathophysiological and neurovascular repair processes of IS are strongly associated with the homeostatic state of the NVU and that further research into therapies directed at the NVU could expand the range of treatments available for IS.

Niche Cells Crosstalk In Neuroinflammation After Traumatic Brain Injury

Traumatic brain injury (TBI) is recognized as the disease with high morbidity and disability around world in spite of the work ongoing in neural protection. Due to heterogeneity among the patients, it's still hard to acquire satisfying achievements in clinic. Neuroinflammation, which exists since primary injury occurs, with elusive duality, appear to be of significance from recovery of injury to neurogenesis. In recent years, studied have revealed that communication in neurogenic niche is more than “cell to cell” communication, and study on NSCs represent it as central role in the progress of neural regeneration. Hence, the neuroinflammation-affecting crosstalk after TBI, and clarifying definitive role of NSCs in the course of regeneration is a promising subject for researchers, for its great potential in overcoming the frustrating status quo in clinic, promoting welfare of TBI patient.

Effects of Exosomes on Neurological Function Recovery for Ischemic Stroke in Pre-clinical Studies: A Meta-analysis

Background: Exosomes, especially stem cell-derived exosomes, have been widely studied in pre-clinical research of ischemic stroke. However, their pooled effects remain inconclusive. Methods: Relevant literature concerning the effects of exosomes on neurological performance in a rodent model of ischemic stroke was identified via searching electronic databases, including PubMed, Embase, and Web of Science. The primary outcomes included neurological function scores (NFS) and infarct volume (IV), and the secondary outcomes were several pro-inflammatory factors and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling-positive cells. Subgroup analyses regarding several factors potentially influencing the effects of exosomes on NFS and IV were also conducted. Results: We identified 21 experiments from 18 studies in the meta-analysis. Pooled analyses showed the positive and significant effects of exosomes on NFS (standardized mean difference -2.79; 95% confidence interval -3.81 to -1.76) and IV (standardized mean difference -3.16; 95% confidence interval -4.18 to -2.15). Our data revealed that the effects of exosomes on neurological outcomes in rodent stroke models might be related to routes of administration and exosomes sources. In addition, there was significant attenuation in pro-inflammatory factors, including interleukin-6, tumor necrosis factor-α and interleukin-1β, and terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling-positive cells when undergoing exosomes treatment. Conclusion: Cell-derived exosomes treatment demonstrated statistically significant improvements in structural and neurological function recovery in animal models of ischemic stroke. Our results also provide relatively robust evidence supporting cell-derived exosomes as a promising therapy to promote neurological recovery in stroke individuals.

Ablation of GSDMD Improves Outcome of Ischemic Stroke Through Blocking Canonical and Non-canonical Inflammasomes Dependent Pyroptosis in Microglia

Ischemia/reperfusion (I/R) injury is a significant cause of mortality and long-term disability worldwide. Recent evidence has proved that pyroptosis, a novel cell death form, contributes to inflammation-induced neuron death and neurological function impairment following ischemic stroke. Gasdermin D (GSDMD) is a newly discovered key molecule of cell pyroptosis, but its biological function and precise role in ischemic stroke are still unclear. The present study investigates the cleavage activity of GSDMD, localization of pyroptotic cells, and global neuroinflammation in gsdmd ^-/- mice after I/R. The level of cell pyroptosis around the infarcted area was significantly increased in the acute phase of cerebral I/R injury. The ablation of GSDMD reduced the infraction volume and improved neurological function against cerebral I/R injury. Furthermore, we confirmed I/R injury induced cell pyroptosis mainly in microglia. Knockdown of GSDMD effectively inhibited the secretion of mature IL-1β and IL-18 from microglia cells but did not affect the expression of caspase-1/11 in vitro and in vivo. In summary, blocking GSDMD expression might serve as a potential therapeutic strategy for ischemic stroke.