Modified exosomal SIRPα variants alleviate white matter injury after intracerebral hemorrhage via microglia/macrophages

Endoscopic nasal delivery of engineered endothelial progenitor cell-derived exosomes improves angiogenesis and neurological deficits in rats with intracerebral hemorrhage

Intracerebral hemorrhage (ICH) remains a life-threatening condition due to its high mortality and limited treatment options. This study explores a novel therapeutic strategy using engineered exosomes derived from endothelial progenitor cells (EPC-EXOs) to improve ICH outcomes. EPC-EXOs were modified with a CD47-enriched red blood cell membrane via co-extrusion to enhance their anti-phagocytic properties, thereby reducing degradation by activated microglia after ICH. A minimally invasive endoscopic-guided delivery system was developed to facilitate the targeted intranasal administration of these engineered EPC-EXOs (m-Oe-EXOs), allowing direct entry into brain tissue. We confirmed m-Oe-EXOs' high retention and effective distribution in the brain. Functional analysis demonstrated that EPC-EXOs significantly promoted the proliferation, migration, and angiogenesis of brain microvascular endothelial cells (BMECs), with proteomic analysis identifying HSP90 as a key protein activating the Akt pathway in BMECs. In vivo, m-Oe-EXOs demonstrated therapeutic efficacy by improving blood-brain barrier integrity, reducing hematoma volume, and enhancing neurological recovery in ICH rats. Collectively, our findings highlight the potential of minimally invasive, endoscopic-guided delivery of m-Oe-EXOs as an innovative approach for ICH treatment, providing new insights into targeted, exosomes-based regenerative therapies.

Activation of GPER1 alleviates white matter injury by promoting microglia M2 polarization through EGFR/Stat3 pathway in intracerebral hemorrhage mice

BACKGROUND

White matter injury (WMI) is a major pathophysiological process after intracerebral hemorrhage (ICH). G protein-coupled estrogen receptor 1 (GPER1) has been validated to exert a crucial role in regulating neuroinflammation and microglia polarization. Our previous report reveals activation of GPER1 improves the neurological deficits after ICH via inhibition of A1 astrocytes. However, the role of GPER1 on the protection of WMI and modulation of microglia polarization after ICH remains unclear.

METHODS

In present study, ICH mice model was induced by autologous whole blood injection and in vitro ICH model was established via treatment BV2 cells with FeSO4. Mice were treated with GPER1 agonist G1, antagonist G15 and BV2 cells were treated with G1, G15 or EGFR inhibitor AG1478. Besides, BV2 conditional medium was used to intervene MO3.13 oligodendrocytes. Immunostaining, immunoblots, transmission electron microscope and PI staining were used to determine the WMI, microglia polarization and potential molecular mechanism after ICH, respectively.

RESULTS

Our data showed treatment with G1 ameliorated the WMI on the day 3 after ICH. Besides, activation of GPER1 reduced the release of IL-1β, TNF-α and increased the produce of IL-4, IL-10 as well as shifting microglia from proinflammatory M1 to anti-inflammatory M2 phenotype in vivo and in vitro. Meanwhile, MO3.13 cells treated with BV2 conditional medium validated GPER1 alleviated oligodendrocytes death via mitigating neuroinflammation and modulating microglia polarization. Mechanistic study demonstrated EGFR/Stat3 signaling pathway was involved in the protection of WMI and modulation microglia polarization after ICH.

CONCLUSION

Collectively, our findings demonstrated activation of GPER1 alleviated WMI via modulating microglia M2 polarization after ICH through EGFR/Stat3 signaling pathway.

Blood-brain barrier repair: potential and challenges of stem cells and exosomes in stroke treatment

Stroke is characterized with high morbidity, mortality and disability all over the world, and one of its core pathologies is blood-brain barrier (BBB) dysfunction. BBB plays a crucial physiological role in protecting brain tissues and maintaining homeostasis in central nervous system (CNS). BBB dysfunction serves as a key factor in the development of cerebral edema, inflammation, and further neurological damage in stroke patients. Currently, stem cells and their derived exosomes have shown remarkable potential in repairing the damaged BBB and improving neurological function after stroke. Stem cells repair the integrity of BBB through anti-inflammatory, antioxidant, angiogenesis and regulation of intercellular signaling mechanisms, while stem cell-derived exosomes, as natural nanocarriers, further enhance the therapeutic effect by carrying active substances such as proteins, RNAs and miRNAs. This review will present the latest research advances in stem cells and their exosomes in stroke treatment, as well as the challenges of cell source, transplantation timing, dosage, and route of administration in clinical application, aiming to discuss their mechanisms of repairing BBB integrity and potential for clinical application, and proposes future research directions. Stem cells and exosomes are expected to provide new strategies for early diagnosis and precise treatment of stroke, and promote breakthroughs in the field of stroke.

Microglial Lcn2 knockout enhances chronic intracerebral hemorrhage recovery by restoring myelin and reducing inflammation

Rationale: Damage to white matter and myelin poses a significant challenge to neurological recovery in the chronic phase of intracerebral hemorrhage (ICH). The repair of myelin damage post-ICH largely depends on the activation and differentiation of oligodendrocyte precursor cells (OPCs) into oligodendrocytes, a process that is significantly influenced by the inflammatory microenvironment. Lipocalin-2 (Lcn2) regulate phenotypic transformation of microglia and thus modulates inflammation. However, the exact role of Lcn2 in facilitating myelin recovery during the chronic phase of ICH remains to be fully understood. Methods: To create the ICH model, autologous blood from male C57BL/6 and Lcn2fl/flCx3cr1Cre mice was utilized. Behavioral tests were conducted to evaluate neurological recovery. The differentiation of OPCs and extent of myelin recovery were assessed using OPC and myelin markers. A multi-factor inflammatory chip was employed to investigate potential molecular regulatory mechanisms. Additionally, the Lcn2 inhibitor ZINC-94/89 was administered to explore its potential in targeting Lcn2 for enhancing myelin recovery during the chronic phase of ICH. Results: Knocking out Lcn2 in microglia significantly improved behavioral performance in chronic ICH mice, reduced inflammatory response, and enhanced myelin recovery. Both in vivo and in vitro experiments confirmed that Lcn2 knockout promoted microglia transformation to the M2 phenotype and enhanced OPCs differentiation. Mechanistically, Lcn2 knockout might affect Gdf-1 secretion in BV2 cells by modulating the JAK/STAT signaling pathway. Treatment with JAK inhibitors decreased Gdf-1 expression in BV2 cells, inhibiting OPCs migration and differentiation. Additionally, phosphorylation of Stat3 at Thr705 plays a critical role in enhancing Gdf-1 transcription and translation. Administration of the Lcn2 inhibitor ZINC-94/89 significantly improved behavioral performance, reduced inflammatory response, and promoted myelin recovery in chronic ICH mice. Conclusions: Lcn2 is crucial for myelin recovery in the chronic phase of ICH by modulating microglial phenotypes, thereby enhancing the migration and differentiation of OPCs. Administering an Lcn2 inhibitor early on could serve as a novel and effective strategy to boost recovery during this phase.

Microglial Mechanisms and Therapeutic Potential in Brain Injury Post-Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a particularly common public health problem with a high mortality and disability rate and no effective treatments to enhance clinical prognosis. The increased aging population, improved vascular prevention, and augmented use of antithrombotic agents have collectively contributed to the rise in ICH incidence over the past few decades. The exploration and understanding of mechanisms and intervention strategies has great practical significance for expanding treatments and improving prognosis of ICH. Microglia, as resident macrophages of central nervous system, are responsible for the first immune defense post-ICH. After ICH, M1 microglia is firstly activated by primary injury and thrombin; subsequently, reactive microglia can further amplify the immune response and exert secondary injury (eg, oxidative stress, neuronal damage, and brain edema). The pro-inflammatory phenotype transmits to M2 microglia within 7 days post-ICH, which plays a key role in erythrophagocytosis and limiting the inflammatory secondary injury. Microglial M2 polarization has significant implications for improving prognosis, this process can be mediated through crosstalk with other cells, metabolic changes, and microbiota interaction. Clarifying the effect, timing, and potential downstream effects of multiple mechanisms that synergistically trigger anti-inflammatory responses may be necessary for clinical translation. Analyses of such intricate interaction between microglia cells and brain injury/repair mechanisms will contribute to our understanding of the critical microglial responses to microenvironment and facilitating the discovery of appropriate intervention strategies. Here, we present a comprehensive overview of the latest evidences on microglial dynamics following ICH, their role in driving primary/secondary injury mechanisms as well as neurorepair/plasticity, and possible treatment strategies targeting microglia.

Beyond cancer: The potential application of CD47-based therapy in non-cancer diseases

CD47 is an immune checkpoint widely regarded as a 'don't eat me' signal. CD47-based anti-cancer therapy has received considerable attention, with a significant number of clinical trials conducted. While anti-cancer therapies based on CD47 remain a focal point of interest among researchers, it is noteworthy that an increasing number of studies have found that CD47-based therapy ameliorated the pathological status of non-cancer diseases. This review aims to provide an overview of the recent progress in comprehending the role of CD47-based therapy in non-cancer diseases, including diseases of the circulatory system, nervous system, digestive system, and so on. Furthermore, we sought to delineate the promising mechanisms of CD47-based therapy in treating non-cancer diseases. Our findings suggest that CD47-based agents may exert their effect by regulating phagocytosis, regulating T cells, dendritic cells, and neutrophils, and regulating the secretion of cytokines and chemokines. Additionally, we put forward the orientation of further research to bring to light the potential of CD47 and its binding partners as a target in non-cancer diseases.

NLRP3 inflammasome and gut microbiota-brain axis: a new perspective on white matter injury after intracerebral hemorrhage

ABSTRACT

Intracerebral hemorrhage is the most dangerous subtype of stroke, characterized by high mortality and morbidity rates, and frequently leads to significant secondary white matter injury. In recent decades, studies have revealed that gut microbiota can communicate bidirectionally with the brain through the gut microbiota-brain axis. This axis indicates that gut microbiota is closely related to the development and prognosis of intracerebral hemorrhage and its associated secondary white matter injury. The NACHT, LRR, and pyrin domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in this context. This review summarizes the dysbiosis of gut microbiota following intracerebral hemorrhage and explores the mechanisms by which this imbalance may promote the activation of the NLRP3 inflammasome. These mechanisms include metabolic pathways (involving short-chain fatty acids, lipopolysaccharides, lactic acid, bile acids, trimethylamine-N-oxide, and tryptophan), neural pathways (such as the vagus nerve and sympathetic nerve), and immune pathways (involving microglia and T cells). We then discuss the relationship between the activated NLRP3 inflammasome and secondary white matter injury after intracerebral hemorrhage. The activation of the NLRP3 inflammasome can exacerbate secondary white matter injury by disrupting the blood-brain barrier, inducing neuroinflammation, and interfering with nerve regeneration. Finally, we outline potential treatment strategies for intracerebral hemorrhage and its secondary white matter injury. Our review highlights the critical role of the gut microbiota-brain axis and the NLRP3 inflammasome in white matter injury following intracerebral hemorrhage, paving the way for exploring potential therapeutic approaches.

White Matter Injury in Central Nervous System Disorders

As the aging process accelerates and living conditions improve, central nervous system (CNS) diseases have become a major public health problem. Diseases of the CNS cause not only gray matter damage, which is primarily characterized by the loss of neurons, but also white matter damage. However, most previous studies have focused on grey matter injury (GMI), with fewer studies on white matter injury (WMI). In this article, we will briefly describe the structure and function of white matter, summarize the pathological changes of WMI, and focus on the molecular mechanisms and therapeutic research advances in WMI after ischemic stroke, cerebral hemorrhage, Alzheimer's disease, and multiple sclerosis diseases.

Exosomes in stroke management: a promising paradigm shift in stroke therapy

Effective treatment methods for stroke, a common cerebrovascular disease with a high mortality rate, are still being sought. Exosome therapy, a form of acellular therapy, has demonstrated promising efficacy in various diseases in animal models; however, there is currently insufficient evidence to guide the clinical application of exosome in patients with stroke. This article reviews the progress of exosome applications in stroke treatment. It aims to elucidate the significant potential value of exosomes in stroke therapy and provide a reference for their clinical translation. At present, many studies on exosome-based therapies for stroke are actively underway. Regarding preclinical research, exosomes, as bioactive substances with diverse sources, currently favor stem cells as their origin. Due to their high plasticity, exosomes can be effectively modified through various physical, chemical, and genetic engineering methods to enhance their efficacy. In animal models of stroke, exosome therapy can reduce neuroinflammatory responses, alleviate oxidative stress damage, and inhibit programmed cell death. Additionally, exosomes can promote angiogenesis, repair and regenerate damaged white matter fiber bundles, and facilitate the migration and differentiation of neural stem cells, aiding the repair process. We also summarize new directions for the application of exosomes, specifically the exosome intervention through the ventricular-meningeal lymphatic system. The review findings suggest that the treatment paradigm for stroke is poised for transformation.

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.

Extracellular vesicle therapy in neurological disorders

Extracellular vesicles (EVs) are vital for cell-to-cell communication, transferring proteins, lipids, and nucleic acids in various physiological and pathological processes. They play crucial roles in immune modulation and tissue regeneration but are also involved in pathogenic conditions like inflammation and degenerative disorders. EVs have heterogeneous populations and cargo, with numerous subpopulations currently under investigations. EV therapy shows promise in stimulating tissue repair and serving as a drug delivery vehicle, offering advantages over cell therapy, such as ease of engineering and minimal risk of tumorigenesis. However, challenges remain, including inconsistent nomenclature, complex characterization, and underdeveloped large-scale production protocols. This review highlights the recent advances and significance of EVs heterogeneity, emphasizing the need for a better understanding of their roles in disease pathologies to develop tailored EV therapies for clinical applications in neurological disorders.

Application of biomaterials in the treatment of intracerebral hemorrhage

Although the current surgical hematoma removal treatment saves patients' lives in critical moments of intracerebral hemorrhage (ICH), the lethality and disability rates of ICH are still very high. Due to the individual differences of patients, postoperative functional improvement is still to be confirmed, and the existing drug treatment has limited benefits for ICH. Recent advances in biomaterials may provide new ideas for the therapy of ICH. This review first briefly describes the pathogenic mechanisms of ICH, including primary and secondary injuries such as inflammation and intracerebral edema, and briefly describes the existing therapeutic approaches and their limitations. Secondly, existing nanomaterials and hydrogels for ICH, including exosomes, liposomes, and polymer nanomaterials, are also described. In addition, the potential challenges and application prospects of these biomaterials for clinical translation in ICH treatment are discussed.

Exosomes-based immunotherapy for cancer: Effective components in the naïve and engineered forms

Today, cancer treatment is one of the main challenges for researchers. The main cause of tumor cell formation is mutations that lead to uncontrolled proliferation and inhibition of apoptosis in malignant cells. Tumor cells also create a microenvironment that can suppress the immune system cells' responses through various methods, including producing soluble factors and cell-to-cell communication. After being produced from tumor cells, exosomes can also affect the functions of other cells in this microenvironment. Various studies have shown that exosomes from different sources, including tumor cells and immune cells, can be used to treat cancers due to their characteristics. Since tumor cells are rich sources of various types of tumor peptides, they can induce anti-tumor responses. Immune cells also produce exosomes that mimic the functions of their cells of origin, such that exosomes derived from NK cells and CTLs can directly lead to their apoptosis after merging with tumor cells. However, many researchers have pointed out that naïve exosomes have a limited therapeutic function, and their therapeutic potential can be increased by manipulating and engineering them. There are various methods to modify exosomes and improve their therapeutic potential. In general, these methods are divided into two parts, which include changing the cell of origin of the exosome and encapsulating the exosome to carry different drugs. In this review, we will discuss the studies on the therapeutic use of naive and engineered exosomes and provide an update on new studies in this field.

Meta-Analysis of the Therapeutic Effects of Stem Cell-Derived Extracellular Vesicles in Rodent Models of Hemorrhagic Stroke

Background

Stem cell-derived extracellular vesicles (SCEVs) have emerged as a potential therapy for hemorrhagic stroke. However, their effects are not fully understood. The aim of this study was to comprehensively evaluate the effects of SCEVs therapy in rodent models of hemorrhagic stroke, including subarachnoid hemorrhage (SAH) and intracerebral hemorrhage (ICH).

Materials and Methods

We conducted a comprehensive search of PubMed, EMBASE, and Web of Science until May 2023 to identify studies investigating the effects of SCEVs therapy in rodent models of ICH. The functional outcomes were assessed using neurobehavioral scores. Standardized mean differences (SMDs) and confidence intervals (CIs) were calculated using a random-effects model. Three authors independently screened the articles based on inclusion and exclusion criteria. All statistical analyses were performed using Revman 5.3 and Stata 17.0.

Results

Twelve studies published between 2018 and 2023 met the inclusion criteria. Our results showed that SCEVs therapy improved neurobehavioral scores in the rodent SAH model (SMD = -3.49, 95% CI: -4.23 to -2.75; p < 0.001). Additionally, SCEVs therapy improved the chronic neurobehavioral scores of the rodent ICH model (SMD = 2.38, 95% CI: 0.36-4.40; p=0.02) but did not have a significant impact on neurobehavioral scores in the acute and subacute phases. Significant heterogeneity was observed among the studies, and further stratification and sensitivity analyses failed to identify the source of heterogeneity.

Conclusions

Our findings suggest that SCEVs therapy may improve neurofunctional behavior after hemorrhagic stroke and provide important insights into the design of preclinical trials.

Recent advances in therapeutic engineered extracellular vesicles

Extracellular vesicles (EVs) are natural particles secreted by living cells, which hold significant potential for various therapeutic applications. Native EVs have specific components and structures, allowing them to cross biological barriers, and circulate in vivo for a long time. Native EVs have also been bioengineered to enhance their therapeutic efficacy and targeting affinity. Recently, the therapeutic potential of surface-engineered EVs has been explored in the treatment of tumors, autoimmune diseases, infections and other diseases by ongoing research and clinical trials. In this review, we will introduce the modified methods of engineered EVs, summarize the application of engineered EVs in preclinical and clinical trials, and discuss the opportunities and challenges for the clinical translation of surface-engineered EVs.

Attenuation of neuronal ferroptosis in intracerebral hemorrhage by inhibiting HDAC1/2: Microglial heterogenization via the Nrf2/HO1 pathway

AIM

The class I histone deacetylases (HDACs) implicate in microglial heterogenization and neuroinflammation following Intracerebral hemorrhage (ICH). Ferroptosis has also been reported in the ICH model. However, the relationship between HDAC1/2's role in microglial heterogenization and neuronal ferroptosis remains unclear.

METHODS

In both in vivo and in vitro models of ICH, we used Romidepsin (FK228), a selective HDAC1/2 inhibitor, to investigate its effects on microglial heterogenization and neuronal ferroptosis. In the in vitro ICH model using Hemin, a transwell system was utilized to examine how microglia-driven inflammation and ICH-triggered neuronal ferroptosis interact. Immunostaining, Western blotting and RT-qPCR were used to evaluate the microglial heterogenization and neuronal ferroptosis. Microglial heterogenization, neuronal ferroptosis, and neurological dysfunctions were assessed in vivo ICH mice model performed by autologous blood injection.

RESULTS

HDAC1/2 inhibition altered microglial heterogenization after ICH, as showing the reducing neuroinflammation and shifting microglia towards an anti-inflammatory phenotype by immunostaining and qPCR results. HDAC1/2 inhibition reduced ferroptosis, characterized by high ROS and low GPx4 expression in HT22 cells, and reduced iron and lipid deposition post-ICH in vivo. Additionally, the Nrf2/HO1 signaling pathway, especially acetyl-Nrf2, activated in the in vivo ICH model due to HDAC1/2 inhibition, plays a role in regulating microglial heterogenization. Furthermore, HDAC1/2 inhibition improved sensorimotor and histological outcomes post-ICH, offering a potential mechanism against ICH.

CONCLUSION

Inhibition of HDAC1/2 reduces neuro-ferroptosis by modifying the heterogeneity of microglia via the Nrf2/HO1 pathway, with a particular focus on acetyl-Nrf2. Additionally, this inhibition aids in the faster removal of hematomas and lessens prolonged neurological impairments, indicating novel approach for treating ICH.

The Crosstalk Between Immune Cells After Intracerebral Hemorrhage

The inflammatory mechanism of intracerebral hemorrhage (ICH) has been widely studied, and it is believed that the regulation of this mechanism is of great significance to the prognosis. In the early stage of the acute phase of ICH, the release of a large number of inflammatory factors around the hematoma can recruit more inflammatory cells to infiltrate the area, further release inflammatory factors, cause an inflammatory cascade reaction, aggravate the volume of cerebral hematoma and edema and further destroy the blood-brain barrier (BBB), according to this, the crosstalk between cells may be of great significance in secondary brain injury (SBI). Because most of the cells recruited are inflammatory immune cells, this paper mainly discusses the cells based on the inflammatory mechanism to discuss their functions after ICH, we found that among the main cells inherent in the brain, glial cells account for the majority, of which microglia are the most widely studied and it can interact with a variety of cells, which is reflected in the literature researches on its pathogenesis and treatment. We believe that exploring multi-mechanism and multi-cell regulated drugs may be the future development trend, and the existing research, the comparison and unification of modeling methods, and the observation of long-term efficacy may be the first problem that researchers need to solve.

Neutrophil-like pH-responsive pro-efferocytic nanoparticles improve neurological recovery by promoting erythrophagocytosis after intracerebral hemorrhage

Rationale: Intracerebral hemorrhage (ICH) is a devastating cerebrovascular disease resulting from blood extravasating into the brain parenchyma. Escalation of erythrophagocytosis (a form of efferocytosis), avoiding the consequent release of the detrimental erythrocyte lysates, may be a promising target of ICH management. The ADAM17 inhibitor and liver X receptor (LXR) agonist could promote efficient efferocytosis and injury repair. Nevertheless, the poor bioavailability and restriction of the blood-brain barrier (BBB) hinder their application. Therefore, it is needed that biocompatible and smart nanoplatforms were designed and synthesized to realize effective therapy targeting erythrophagocytosis. Methods: We first assessed the synergistic effect of therapeutic GW280264X (an ADAM17 inhibitor) and desmosterol (an LXR agonist) on erythrophagocytosis in vitro. Then a pH-responsive neutrophil membrane-based nanoplatform (NPEOz) served as a carrier to accurately deliver therapeutic GW280264X and desmosterol to the damaged brain was prepared via co-extrusion. Afterwards, their pH-responsive performance was valued in vitro and targeting ability was assessed through fluorescence image in vivo. Finally, the pro-erythrophagocytic and anti-neuroinflammatory ability of the nanomedicine and related mechanisms were investigated. Results: After the synergistical effect of the above two drugs on erythrophagocytosis was confirmed, we successfully developed neutrophil-disguised pH-responsive nanoparticles to efficiently co-deliver them. The nanoparticles could responsively release therapeutic agents under acidic environments, and elicit favorable biocompatibility and ability of targeting injury sites. D&G@NPEOz nanoparticles enhanced erythrophagocytosis through inhibiting shedding of the efferocytotic receptors MERTK/AXL mediated by ADAM17 and accelerating ABCA-1/ABCG-1-mediated cholesterol efflux regulated by LXR respectively. In addition, the nano-formulation was able to modulate the inflammatory microenvironment by transforming efferocytes towards a therapeutic phenotype with reducing the release of proinflammatory cytokines while increasing the secretion of anti-inflammatory factors, and improve neurological function. Conclusions: This biomimetic nanomedicine is envisaged to offer an encouraging strategy to effectively promote hematoma and inflammation resolution, consequently alleviate ICH progression.

Spi1 regulates the microglial/macrophage inflammatory response via the PI3K/AKT/mTOR signaling pathway after intracerebral hemorrhage

Preclinical and clinical studies have shown that microglia and macrophages participate in a multiphasic brain damage repair process following intracerebral hemorrhage. The E26 transformation-specific sequence-related transcription factor Spi1 regulates microglial/macrophage commitment and maturation. However, the effect of Spi1 on intracerebral hemorrhage remains unclear. In this study, we found that Spi1 may regulate recovery from the neuroinflammation and neurofunctional damage caused by intracerebral hemorrhage by modulating the microglial/macrophage transcriptome. We showed that high Spi1 expression in microglia/macrophages after intracerebral hemorrhage is associated with the activation of many pathways that promote phagocytosis, glycolysis, and autophagy, as well as debris clearance and sustained remyelination. Notably, microglia with higher levels of Spi1 expression were characterized by activation of pathways associated with a variety of hemorrhage-related cellular processes, such as complement activation, angiogenesis, and coagulation. In conclusion, our results suggest that Spi1 plays a vital role in the microglial/macrophage inflammatory response following intracerebral hemorrhage. This new insight into the regulation of Spi1 and its target genes may advance our understanding of neuroinflammation in intracerebral hemorrhage and provide therapeutic targets for patients with intracerebral hemorrhage.

Engineered Extracellular Vesicles: A potential treatment for regeneration

Extracellular vesicles (EVs) play a critical role in various physiological and pathological processes. EVs have gained recognition in regenerative medicine due to their biocompatibility and low immunogenicity. However, the practical application of EVs faces challenges such as limited targeting ability, low yield, and inadequate therapeutic effects. To overcome these limitations, engineered EVs have emerged. This review aims to comprehensively analyze the engineering methods utilized for modifying donor cells and EVs, with a focus on comparing the therapeutic potential between engineered and natural EVs. Additionally, it aims to investigate the specific cell effects that play a crucial role in promoting repair and regeneration, while also exploring the underlying mechanisms involved in the field of regenerative medicine.

To re-examine the intersection of microglial activation and neuroinflammation in neurodegenerative diseases from the perspective of pyroptosis

Neurodegenerative diseases (NDs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and motor neuron disease, are diseases characterized by neuronal damage and dysfunction. NDs are considered to be a multifactorial disease with diverse etiologies (immune, inflammatory, aging, genetic, etc.) and complex pathophysiological processes. Previous studies have found that neuroinflammation and typical microglial activation are important mechanisms of NDs, leading to neurological dysfunction and disease progression. Pyroptosis is a new mode involved in this process. As a form of programmed cell death, pyroptosis is characterized by the expansion of cells until the cell membrane bursts, resulting in the release of cell contents that activates a strong inflammatory response that promotes NDs by accelerating neuronal dysfunction and abnormal microglial activation. In this case, abnormally activated microglia release various pro-inflammatory factors, leading to the occurrence of neuroinflammation and exacerbating both microglial and neuronal pyroptosis, thus forming a vicious cycle. The recognition of the association between pyroptosis and microglia activation, as well as neuroinflammation, is of significant importance in understanding the pathogenesis of NDs and providing new targets and strategies for their prevention and treatment.

Insight into extracellular vesicles in vascular diseases: intercellular communication role and clinical application potential

BACKGROUND

Cells have been increasingly known to release extracellular vesicles (EVs) to the extracellular environment under physiological and pathological conditions. A plethora of studies have revealed that EVs contain cell-derived biomolecules and are found in circulation, thereby implicating them in molecular trafficking between cells. Furthermore, EVs have an effect on physiological function and disease development and serve as disease biomarkers.

MAIN BODY

Given the close association  between EV circulation and vascular disease, this review aims to provide a brief introduction to EVs, with a specific focus on the EV cargoes participating in pathological mechanisms, diagnosis, engineering, and clinical potential, to highlight the emerging evidence suggesting promising targets in vascular diseases. Despite the expansion of research in this field, some noticeable limitations remain for clinical translational research.

CONCLUSION

This review makes a novel contribution to a summary of recent advances and a perspective on the future of EVs in vascular diseases. Video Abstract.

Exosomal Mir-3613-3p derived from oxygen-glucose deprivation-treated brain microvascular endothelial cell promotes microglial M1 polarization

BACKGROUND

Brain microvascular endothelial cell (BMEC) injury can affect neuronal survival by modulating immune responses through the microenvironment. Exosomes are important vehicles of transport between cells. However, the regulation of the subtypes of microglia by BMECs through the exosome transport of microRNAs (miRNAs) has not been established.

METHODS

In this study, exosomes from normal and oxygen-glucose deprivation (OGD)-cultured BMECs were collected, and differentially expressed miRNAs were analyzed. BMEC proliferation, migration, and tube formation were analyzed using MTS, transwell, and tube formation assays. M1 and M2 microglia and apoptosis were analyzed using flow cytometry. miRNA expression was analyzed using real-time polymerase chain reaction (RT-qPCR), and IL-1β, iNOS, IL-6, IL-10, and RC3H1 protein concentrations were analyzed using western blotting.

RESULTS

We found that miR-3613-3p was enriched in BMEC exosome by miRNA GeneChip assay and RT-qPCR analysis. miR-3613-3p knockdown enhanced cell survival, migration, and angiogenesis in the OGD-treated BMECs. In addition, BMECs secrete miR-3613-3p to transfer into microglia via exosomes, and miR-3613-3p binds to the RC3H1 3' untranslated region (UTR) to reduce RC3H1 protein levels in microglia. Exosomal miR-3613-3p promotes microglial M1 polarization by inhibiting RC3H1 protein levels. BMEC exosomal miR-3613-3p reduces neuronal survival by regulating microglial M1 polarization.

CONCLUSIONS

miR-3613-3p knockdown enhances BMEC functions under OGD conditions. Interfering with miR-3613-3p expression in BMSCs reduced the enrichment of miR-3613-3p in exosomes and enhanced M2 polarization of microglia, which contributed to reduced neuronal apoptosis.