Extracellular Vesicle-Mediated Delivery of Circular RNA SCMH1 Promotes Functional Recovery in Rodent and Nonhuman Primate Ischemic Stroke Models

Utilizing engineered extracellular vesicles as delivery vectors in the management of ischemic stroke: a special outlook on mitochondrial delivery

Ischemic stroke is a secondary cause of mortality worldwide, imposing considerable medical and economic burdens on society. Extracellular vesicles, serving as natural nano-carriers for drug delivery, exhibit excellent biocompatibility in vivo and have significant advantages in the management of ischemic stroke. However, the uncertain distribution and rapid clearance of extracellular vesicles impede their delivery efficiency. By utilizing membrane decoration or by encapsulating therapeutic cargo within extracellular vesicles, their delivery efficacy may be greatly improved. Furthermore, previous studies have indicated that microvesicles, a subset of large-sized extracellular vesicles, can transport mitochondria to neighboring cells, thereby aiding in the restoration of mitochondrial function post-ischemic stroke. Small extracellular vesicles have also demonstrated the capability to transfer mitochondrial components, such as proteins or deoxyribonucleic acid, or their sub-components, for extracellular vesicle-based ischemic stroke therapy. In this review, we undertake a comparative analysis of the isolation techniques employed for extracellular vesicles and present an overview of the current dominant extracellular vesicle modification methodologies. Given the complex facets of treating ischemic stroke, we also delineate various extracellular vesicle modification approaches which are suited to different facets of the treatment process. Moreover, given the burgeoning interest in mitochondrial delivery, we delved into the feasibility and existing research findings on the transportation of mitochondrial fractions or intact mitochondria through small extracellular vesicles and microvesicles to offer a fresh perspective on ischemic stroke therapy.

Edaravone ameliorates inflammation in ischemic stroke mouse by regulating the CYP1A1 pathway through gut microbiota

Inflammation is one of the main contributors to post-stroke injuries, and the disorders of the gut-brain axis post-stroke can further induce inflammation. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one, EDA) is widely utilized neuroprotective medication for ischemic stroke in Japan, China, India, and other countries. However, the effects of EDA on peripheral inflammation and gut-brain axis repair post-stroke have not been revealed yet. In this study, we employed network pharmacology to identify the potential anti-inflammatory targets and signaling pathways that EDA may influence in the treatment of ischemic stroke. Then, we used 16S rDNA sequencing and molecular docking techniques to determine whether the anti-inflammatory effects of EDA are dependent on the gut-brain axis. Using morphological and molecular biology methods, we investigate how EDA reduces inflammatory response after ischemic stroke through gut microbiota and its metabolites. We demonstrated that EDA alleviated central and peripheral inflammation and rescued gut microbiota dysbiosis post-stroke. Meanwhile, EDA also improved intestinal histological features and decreased intestinal inflammation of post-stroke. The network pharmacology, 16S rDNA sequencing, and molecular docking results revealed that EDA could bind with the ESR1 and thereby regulate the expression of CYP1A1. Furthermore, EDA regulated CYP1A1-related metabolism and decreased the level of 20-HETE post-stroke through gut microbiota. Our study confirmed that EDA alleviated central and peripheral inflammation post-stroke by inhibiting CYP1A1 and CYP1A1-related metabolic through gut microbiota. CYP1A1 was a candidate target for treating ischemic stroke.

Plasma expression level of Hsa_circ_0099734 is associated with atrial fibrillation and its poor prognosis

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia characterized by severe complications such as stroke, resulting in high disability and mortality rates. A circular RNA (circRNA) hsa_circ_0099734 was found significantly expressed in the atrial tissue of AF patients and controls in our previous work. In this study, we aim to reveal the association between hsa_circ_0099734 and AF as well as its poor prognosis, offering novel perspectives for clinical treatment.

METHODS

A 1:1 matched case-control study was designed to examine the association between hsa_circ_0099734 and AF. A prospective cohort study was conducted to investigate the association between hsa_circ_0099734 and AF prognosis using Cox proportional hazards regression analysis.

RESULTS

An elevated plasma level of hsa_circ_0099734 was an independent risk factor for AF in a multivariable conditional logistic regression model (OR 3.23, 95 % CI: 1.11-9.44; P = 0.032). Regarding the prognostic role of hsa_circ_0099734, the multivariable Cox regression analysis indicated that a high level of hsa_circ_0099734 in plasma was an independent risk factor for stroke in patients with AF (HR 2.87, 95 % CI: 1.90-4.35; P < 0.001), and also an independent risk factor for all-cause mortality in AF patients (HR 3.16, 95 % CI: 2.25-4.45; P < 0.001). Adding hsa_circ_0099734 to the CHA2DS2-VA score provided better reclassification and net clinical benefit than the ABC risk score.

CONCLUSIONS

The plasma level of hsa_circ_0099734 was associated with AF risk and the occurrence of stroke or all-cause mortality in AF patients. Hsa_circ_0099734 has the potential to be a non-invasive biomarker for predicting AF and its poor prognosis.

Knockdown of YTHDF2 mitigates OGD-induced microglial inflammation by preventing m6A-dependent PARP14 degradation

Neuroinflammation is a key pathological factor in ischemic brain diseases, contributing to the initiation and progression of these conditions. The function of the m6A reader protein YTHDF2 in regulating neuroinflammation across various neurological contexts. To elucidate the role and regulatory mechanism of YTHDF2 in inflammation under ischemic-like conditions, this study employed an in vitro model, exposing microglia to oxygen-glucose deprivation (OGD) to mimic the stress environment. And through YTHDF2 knockdown, we investigated its effect on OGD-induced inflammation. The results demonstrated that YTHDF2 knockdown significantly suppressed the expression of pro-inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), in OGD-treated microglia. Mechanistic analysis revealed that YTHDF2 interacts with Parp14 mRNA under OGD conditions, reducing its RNA stability via m6A-dependent mechanisms, which in turn decreases Poly (ADP-ribose) polymerase family, member 14 (PARP14) protein expression. Additionally, YTHDF2 knockdown after OGD promoted a PARP14-driven phenotypic switch in microglia from the pro-inflammatory M1 state to the anti-inflammatory M2 state, resulting in diminished inflammation. These findings offer new insights into the regulatory function of YTHDF2 in OGD-induced microglial inflammation and propose m6A modification as a potential therapeutic target for alleviating neuroinflammation.

Tissue Engineering and Regenerative Medicine: Perspectives and Challenges

From the pioneering days of cell therapy to the achievement of bioprinting organs, tissue engineering, and regenerative medicine have seen tremendous technological advancements, offering solutions for restoring damaged tissues and organs. However, only a few products and technologies have received United States Food and Drug Administration approval. This review highlights significant progress in cell therapy, extracellular vesicle-based therapy, and tissue engineering. Hematopoietic stem cell transplantation is a powerful tool for treating many diseases, especially hematological malignancies. Mesenchymal stem cells have been extensively studied. The discovery of induced pluripotent stem cells has revolutionized disease modeling and regenerative applications, paving the way for personalized medicine. Gene therapy represents an innovative approach to the treatment of genetic disorders. Additionally, extracellular vesicle-based therapies have emerged as rising stars, offering promising solutions in diagnostics, cell-free therapeutics, drug delivery, and targeted therapy. Advances in tissue engineering enable complex tissue constructs, further transforming the field. Despite these advancements, many technical, ethical, and regulatory challenges remain. This review addresses the current bottlenecks, emphasizing novel technologies and interdisciplinary research to overcome these hurdles. Standardizing practices and conducting clinical trials will balance innovation and regulation, improving patient outcomes and quality of life.

Nose-to-Brain Delivery of Circular RNA SCMH1-Loaded Lipid Nanoparticles for Ischemic Stroke Therapy

Ischemic stroke represents one of the leading cerebrovascular diseases with a high rate of mortality and disability globally. To date, there are no effective clinical drugs available to improve long-term outcomes for post-stroke patients. A novel nucleic acid agent circSCMH1 which can promote sensorimotor function recovery in rodent and nonhuman primate animal stroke models has been found. However, there are still delivery challenges to overcome for its clinical implementation. Besides, its effects on post-stroke cognitive functions remain unexplored. Herein, lipid nanoparticle circSCMH1@LNP1 is established to deliver circSCMH1 and explore its therapeutic efficacy comprehensively. Distribution experiments demonstrate that intranasal administration of circSCMH1@LNP1 significantly increases circSCMH1 distribution in the peri-infarct region and reduces its non-specific accumulation in other organs compared to intravenous injection. Therapeutic results indicate that circSCMH1@LNP1 promotes synaptic plasticity, vascular repair, neuroinflammation relief, and myelin sheath formation, thereby achieving enhanced sensorimotor and cognitive function recovery in post-stroke mice. In conclusion, this research presents a simple and effective LNP system for efficient delivery of circSCMH1 via intranasal administration to repair post-stroke brain injury. It is envisioned that this study may bridge a crucial gap between basic research and translational application, paving the way for clinical implementation of novel circSCMH1 in post-stroke patient management.

Human and pathogen-encoded circular RNAs in viral infections: insights into functions and therapeutic opportunities

Circular RNAs (circRNAs) are emerging as important regulatory molecules in both host and viral systems, acting as microRNA sponges, protein decoys or scaffolds, and templates for protein translation. Host-derived circRNAs are increasingly recognized for their roles in immune responses, while virus-encoded circRNAs, especially those from DNA viruses, have been shown to modulate host cellular machinery to favor viral replication and immune evasion. Recently, RNA virus-encoded circRNAs were also discovered, but evidence suggests that they might be generated using a different mechanism compared to the circRNAs produced from the host and DNA viruses. This review highlights recent advances in our understanding of both host and virus-derived circRNAs, with a focus on their biological roles and contributions to pathogenesis. Furthermore, we discuss the potential of circRNAs as biomarkers and their application as therapeutic targets or scaffolds for RNA-based therapies. Understanding the roles of circRNAs in host-virus interactions offers novel insights into RNA biology and opens new avenues for therapeutic strategies against viral diseases and associated cancers.

CD4+ T cells in ischemic stroke: effects and therapeutic targets

Ischemic stroke (IS) is a significant contributor to disability and death worldwide, with limited treatments beyond early intervention. The importance of CD4+ T cells in the advancement of IS has been highlighted by recent studies, providing new insights into immunomodulatory strategies. This review describes the spatiotemporal dynamics of CD4+ T cells and their subsets at different stages of IS. The signaling pathways activated by IS regulate the distribution of CD4+ T cells and their subsets, which further influences the inflammatory response and disease progression. In the acute and subacute stages, CD4+ T cells exacerbate neuronal damage. In contrast, CD4+ T cells, which are predominantly composed of Treg cells (Tregs), promote tissue repair and neurological recovery in the chronic stage. In light of recent findings that challenge traditional views, we analyze the underlying mechanisms and potential explanations for these discrepancies. In addition, we summarize the potential of targeting CD4+ T cells as a therapeutic strategy for IS. Although no drugs specifically targeting CD4+ T cells have been developed, certain drugs that modulate CD4+ T cells show potential for IS treatment. Moreover, multitarget drugs integrated with nanomaterials are currently undergoing preclinical investigation. We further explore the challenges in the clinical translation of CD4+ T-cell-targeted therapies and discuss potential strategies to address these challenges. In conclusion, a deeper comprehension of the complex effects of CD4+ T cells and their subsets on IS will contribute to disease management and drug development, thereby improving the quality of life for IS patients.

MeCP2 Lactylation Protects against Ischemic Brain Injury by Transcriptionally Regulating Neuronal Apoptosis

Lactate plays diverse roles in brain pathophysiology, including ischemic stroke. Here, the role of lysine lactylation, an epigenetic modification of lactate, in cerebral ischemia is investigated. Using a mouse model of transient middle cerebral artery occlusion, increased brain lactate levels and global protein lactylation are observed. Proteomics analysis reveals significant lactylation of non-histone proteins in the ischemic penumbra. Lactylation of MeCP2, a transcriptional regulator, is identified as a protective mechanism against stroke-induced neuronal death. Inhibition of MeCP2 lactylation through chemical or genetic manipulation increases infarct volume and aggravates neurological deficits. Mechanistically, MeCP2 lactylation at K210/K249 represses the transcription of apoptosis-associated genes, including Pdcd4 and Pla2g6, thereby attenuating neuronal apoptosis. Additionally, HDAC3 and p300 are identified as key enzymes that regulate MeCP2 lactylation post-stroke. The findings suggest that MeCP2 lactylation offers a potential therapeutic target for alleviating neuronal damage and improving stroke outcomes.

Hydroxysafflor yellow A inhibits neuronal ferroptosis and ferritinophagy in ischemic stroke

Ischemic stroke is a significant cause of disability and mortality on a global scale, with neuronal dysfunction playing a critical role in its pathogenesis. Conventional treatment approaches for ischemic stroke involve surgical interventions and thrombolytic therapy, yet these methods frequently result in ischemia/reperfusion (I/R) injury. Recent studies have underscored the implication of diverse programmed cell death mechanisms, including ferroptosis, in the progression of ischemic stroke. Ferroptosis, a newly recognized form of cell death reliant on iron, is intricately linked to various neurological conditions. Despite the existing body of research on ferritinophagy and neuronal ferroptosis in the context of cerebral ischemia-reperfusion injury, there is a lack of understanding regarding the mechanisms involved in neuronal ferroptosis. This study seeks to explore the relationship between neuronal autophagy and neuronal ferroptosis using in vivo and in vitro models of cerebral ischemia/reperfusion. The findings of our study reveal a significant upregulation of the ferritinophagy-associated protein NCOA4 following cerebral ischemia/reperfusion, concomitant with the initiation of ferroptosis in neuronal cells. This observation offers compelling support for a direct association between neuronal ferritinophagy and ferroptosis. Hydroxysafflor Yellow A (HSYA), a traditional Chinese herb, shows promise in reducing brain ischemia/reperfusion injury, but its exact protective mechanism is still unknown. Our study reveals a new way HSYA protects the brain by preventing neuronal ferroptosis after a stroke, a mechanism not previously reported.

Regulatory mechanisms of m6A RNA methylation in esophageal cancer: a comprehensive review

Esophageal cancer is an aggressively malignant neoplasm characterized by a high mortality rate. Frequently diagnosed at an advanced stage, it presents challenges for optimal therapeutic intervention due to its non-specific symptoms, resulting in lost opportunities for effective treatment, such as surgery, radiotherapy, chemotherapy and target therapy. The N6-methyladenosine (m6A) modification represents the most critical post-transcriptional modification of eukaryotic messenger RNA (mRNA). The reversible m6A modification is mediated by three regulatory factors: m6A methyltransferases, demethylating enzymes, and m6A recognition proteins. These components identify and bind to specific RNA methylation sites, thereby modulating essential biological functions such as RNA processing, nuclear export, stability, translation and degradation, which significantly influence tumorigenesis, invasion, and metastasis. Given the importance of m6A modification, this paper offers a comprehensive examination of the regulatory mechanisms, biological functions, and future therapeutic implications of m6A RNA methylation in the context of esophageal cancer.

Resting-State fMRI and Post-Ischemic Stroke Functional Recovery: Unraveling Causality and Predicting Therapeutic Targets

Research on functional recovery after ischemic stroke has primarily focused on non-invasive brain stimulation and motor rehabilitation therapies, while direct pharmacological interventions are relatively underexplored. This study utilized a bidirectional Mendelian randomization approach to investigate the causal relationship between 191 resting-state functional magnetic resonance imaging (rs-fMRI) features and post-ischemic stroke functional recovery (PISFR). Significant rs-fMRI phenotypes were identified, and Mendelian randomization was employed to determine their associated proteins. Bidirectional Mendelian randomization identified four rs-fMRI phenotypes potentially associated with functional recovery after ischemic stroke. Subsequent MR analysis, using pheno12 as the outcome and plasma protein as the exposure, highlighted Fas-Associated protein with Death Domain (FADD) as a significant protein. Further exploration within the protein-protein interaction (PPI) network identified FADD, Cysteinyl Aspartate Specific Proteinase 8 (CASP8), and Receptor-Interacting Serine/Threonine-Protein Kinase 1 (RIPK1) as potential drug targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that these proteins are involved in the extrinsic apoptotic pathway, providing new insights for pharmacological strategies in post-ischemic stroke recovery. This study offers genetic evidence linking rs-fMRI to functional recovery post-ischemic stroke and identifies potential drug targets that may facilitate therapeutic interventions to enhance recovery after ischemic stroke.

Extracellular particles: emerging insights into central nervous system diseases

Extracellular particles (EPs), including extracellular vesicles (EVs) and non-vesicular extracellular particles (NVEPs), are multimolecular biomaterials released by cells that play a crucial role in intercellular communication. Recently, new subtypes of EPs associated with central nervous system (CNS), such as exophers and supermeres have been identified. These EPs provide new perspectives for understanding the pathological progression of CNS disorders and confer potential diagnostic value for liquid biopsies in neurodegenerative diseases (NDs). Moreover, EPs have emerged as promising drug delivery vehicles and targeted platforms for CNS-specific therapies. In this review, we delineate the landscape of EP subtypes and their roles in the pathophysiology of CNS diseases. We also review the recent advances of EP-based diagnosis in NDs and highlight the importance of analytical platforms with single-particle resolution in the exploitation of potential biomarkers. Furthermore, we summarize the application of engineered EVs in the treatment of CNS diseases and outline the underexplored potential of NVEPs as novel therapeutic agents.

Circular RNAs modulate cancer drug resistance: advances and challenges

Acquired drug resistance is a main factor contributing to cancer therapy failure and high cancer mortality, highlighting the necessity to develop novel intervention targets. Circular RNAs (circRNAs), an abundant class of RNA molecules with a closed loop structure, possess characteristics including high stability, which provide unique advantages in clinical application. Growing evidence indicates that aberrantly expressed circRNAs are associated with resistance against various cancer treatments, including targeted therapy, chemotherapy, radiotherapy, and immunotherapy. Therefore, targeting these aberrant circRNAs may offer a strategy to improve the efficiency of cancer therapy. Herein, we present a summary of the most recently studied circRNAs and their regulatory roles on cancer drug resistance. With the advances in artificial intelligence (AI)-based bioinformatics algorithms, circRNAs could emerge as promising biomarkers and intervention targets in cancer therapy.

Extracellular Vesicles as a Potential Therapy for Stroke

Although thrombolytic therapy has enjoyed relative success, limitations remain, such as a narrow therapeutic window and inconsistent efficacy. Consequently, there is a pressing need to develop novel therapeutic approaches. In recent years, extracellular vesicles (EVs) have garnered increasing attention as a potential alternative to stem cell therapy. Because of their ability to cross the blood-brain barrier and exert neuroprotective effects in cerebral ischemia and hemorrhage, the exploration of EVs for clinical application in stroke treatment is expanding. EVs are characterized by high heterogeneity, with their composition closely mirroring that of their parent cells. This property enables EVs to distinguish between cerebral ischemia and hemorrhage, thus facilitating a more rapid and accurate diagnosis. Additionally, EVs can be engineered to carry specific molecules, such as miRNAs, targeting them to specific cells, potentially enhancing the therapeutic outcome and improving stroke prognosis. In this review, we will also explore the methodologies for the isolation and extraction of EVs, critically evaluating the advantages and disadvantages of various commonly employed separation techniques. Furthermore, we will briefly address current EV preservation and administration methods, providing a comprehensive overview of the state of EV-based therapies in stroke treatment.

Circular RNA circDCUN1D4 suppresses hepatocellular carcinoma development via targeting the miR-590-5p/ TIMP3 axis

Hepatocellular carcinoma (HCC) is a major global health concern, necessitating innovative therapeutic strategies. In this study, we investigated the functional role of circular RNA circDCUN1D4 in HCC progression and its potential therapeutic implications. It was found that HCC patients exhibiting higher levels of circDCUN1D4 demonstrated a more favorable survival rate. Furthermore, we revealed that circDCUN1D4 suppressed HCC cell proliferation, migration, and invasion. Mechanistically, circDCUN1D4 was identified as a sponge for miR-590-5p, leading to the downregulation of its downstream target, Tissue Inhibitor of Metalloproteinase 3 (TIMP3). Importantly, circDCUN1D4 administration through In vivo jet-PEI exhibited a robust inhibitory effect on tumor progression without causing notable toxicity in mice. Overall, our findings highlight circDCUN1D4 as a promising therapeutic candidate for HCC, unraveling its intricate regulatory role through the miR-590-5p/TIMP3 axis. This study contributes valuable insights into the potential clinical applications of circRNA-based therapies for HCC.

Intranasal delivery of engineered extracellular vesicles promotes neurofunctional recovery in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of disability in adults, significantly affecting patients' quality of life. Extracellular vesicles (EVs) derived from human adipose-derived mesenchymal stem cells (hADSCs) have demonstrated therapeutic potential in TBI treatment. However, their limited targeting ability, short half-life, and low bioavailability present significant challenges for clinical application. In this study, we engineered extracellular vesicles (EEVs) by transfecting hADSCs with lentivirus and incorporating ultra-small paramagnetic nanoparticles (USPNs), resulting in EVs with enhanced miRNA expression and targeted delivery capabilities. These EEVs were administered intranasally to specifically target injury sites, effectively modulating the NF-κB signaling pathway to suppress neuroinflammation. In both in vitro and in vivo assessments, EEVs exhibited superior efficacy in promoting neurofunctional recovery and neurogenesis after brain injury compared to unmodified EVs. Furthermore, validation using human brain organoid models confirmed EEVs' remarkable ability to suppress neuroinflammation, offering a promising strategy for TBI treatment.

Engineered extracellular vesicles: an emerging nanomedicine therapeutic platform

The intercellular communication role of extracellular vesicles has been widely proved in various organisms. Compelling evidence has illustrated the involvement of these vesicles in both physiological and pathological processes. Various studies indicate that extracellular vesicles surpass conventional synthetic drug carriers, owing to their abundance in organisms, enhanced targeting ability and low immunogenicity. Therefore, extracellular vesicles have been deemed to be potential drug carriers for the treatment of various diseases, and related studies have increased rapidly. Here, we intend to provide a comprehensive and in-depth review of recent advances in the sources, delivery function, extraction and cargo-loading technologies of extracellular vesicles, as well as their clinical potential in constructing emerging nanomedicine therapeutic platforms. In particular, microfluidic-based isolation and drug-loading technologies, as well as the treatment of various diseases, are highlighted. We also make comparisons between extracellular vesicles and other conventional drug carriers and discuss the challenges in developing drug delivery platforms for clinical translation.

hESC-derived extracellular vesicles enriched with MFGE-8 and the GSH redox system act as senotherapeutics for neural stem cells in ischemic stroke

Human embryonic stem cells (hESCs) and their extracellular vesicles (EVs) hold significant potential for tissue repair and regeneration. Neural stem cells (NSCs) in the adult brain often acquire senescent phenotypes after ischemic injuries, releasing neurodegenerative senescence-associated secretory phenotype factors. In this study, we investigated the senotherapeutic effects of hESC-EVs on NSCs and confirmed their neuroprotective effects in neurons via rejuvenation of NSC secretions. Proteomic profiling of hESC-EVs identified MFGE-8 as a critical bridging molecule to NSCs. We also found that the glutathione (GSH) redox system is a key contributor to the therapeutic antioxidant activity of hESC-EVs. Additionally, EVs produced by the hypoxic preconditioning of hESCs (hESC-HypoxEVs) exhibited reinforced GSH redox capacity and further enhanced the senotherapeutic effects on NSCs compared to naïve hESC-EVs. We also demonstrated that administration of hESC-HypoxEVs, precoated with MFGE-8, significantly increased the populations of NSCs and newborn neurons in the subventricular zone of the brain and improved sensorimotor functions in a rat model of ischemic stroke. Our study suggests that combining hESC-HypoxEVs with MFGE-8 may serve as an effective therapeutic modality for reversing senescence and enhancing the neurogenic potential of NSCs to treat neurodegenerative diseases.

CircTBCK protects against osteoarthritis by regulating extracellular matrix and autophagy

Osteoarthritis (OA) is a widespread chronic bone and joint disease for which there is currently no effective preventive or therapeutic treatment. Accumulating evidence indicates that circular RNAs (circRNAs), a class of noncoding RNAs, play critical roles in OA. Therefore, in this study, we aimed to reveal an unexplored circTBCK and elucidate its mechanism of action in the pathological process of OA. The different expression of circTBCK was obtained both in vitro and in vivo. In the in vivo model, mice were induced via destabilization of the medial meniscus (DMM) surgery, while in vitro model, mouse cells like primary chondrocytes of newborn mice and ATDC5 cell line were treated with IL-1β treatment (10 ng/mL for 24 h). The level of circTBCK was examined by quantitative real-time polymerase chain reaction (qRT-PCR). After circTBCK was overexpressed or knocked down, IL-1β treatment was performed, and then, chondrocyte viability was detected via a Cell Counting Kit-8 (CCK-8) assay at 0, 24, 48, or 72 h. To assess type II collagen (Collagen II) expression, immunofluorescence (IF) analysis was used. The levels of mRNAs and proteins related to proliferation, the extracellular matrix (ECM) and autophagy were determined by qRT-PCR and Western blotting. Compared with OA treatment, primary chondrocytes with treatment of both circTBCK overexpression and IL-1βincreased the expression of anabolic factors-Collagen II and SRY-box transcription factor 9 (SOX9), proliferation-related molecules-Ki-67 and proliferating cell nuclear antigen (PCNA), and autophagy-related molecules-Microtubule-associated protein 1 light chain 3 (LC3), B-cell lymphoma 1 (Bcl1), and autophagy-related 5 (Atg5) and decreased Sequestosome 1 (SQSTM1 or P62). In contrast, knockdown of circTBCK aggravated the chondrocyte degeneration induced by IL-1β. Overall, our findings suggest that circTBCK, an unexplored circRNA, could regulate autophagy, proliferation, and the extracellular matrix (ECM) to mitigate the development of OA, suggesting a possible target for OA prevention and therapy.

Extracellular vesicles as drug and gene delivery vehicles in central nervous system diseases

Extracellular vesicles (EVs) are secreted by almost all cell types and contain DNA, RNA, proteins, lipids and other metabolites. EVs were initially believed to be cellular waste but now recognized for their role in cell-to-cell communication. Later, EVs from immune cells were discovered to function similarly to their parent cells, paving the way for their use as gene and drug carriers. EVs from different cell types or biological fluids carry distinct cargo depending on their origin, and they perform diverse functions. For instance, EVs derived from stem cells possess pluripotent properties, reflecting the cargo from their parent cells. Over the past two decades, substantial preclinical and clinical research has explored EVs-mediated drug and gene delivery to various organs, including the brain. Natural or intrinsic EVs may be effective for certain applications, but as drug or gene carriers, they demonstrate broader and more efficient potential across various diseases. Here, we review research on using EVs to treat central nervous system (CNS) diseases, such as Alzheimer's Disease, Parkinson diseases, depression, anxiety, dementia, and acute ischemic strokes. We first reviewed the naïve EVs, especially mesenchymal stem cell (MSC) derived EVs in CNS diseases and summarized the clinical trials of EVs in treating CNS diseases and highlighted the reports of two complete trials. Then, we overviewed the preclinical research of EVs as drug and gene delivery vehicles in CNS disease models, including the most recent two years' progress and discussed the mechanisms and new methods of engineered EVs for targeting CNS. Finally, we discussed challenges and future directions and of EVs as personalized medicine for CNS diseases.

Eucommia ulmoides Oliv. Bark Extracts Alleviate MCAO/Reperfusion-Induced Neurological Dysfunction by Suppressing Microglial Inflammation in the Gray Matter

Ischemic stroke ranks as the second leading cause of global mortality. The limited time for effective thrombolytic treatment has prompted the exploration of alternative prevention approaches. Eucommia ulmoides (E. ulmoides) Oliv. bark has shown multiple pharmacological effects, including neuroprotection, anti-inflammation and autophagy modulation. This study aims to elucidate the neuroprotective effects of water extract of E. ulmoides (WEU) supplementation in a middle cerebral artery occlusion (MCAO) mouse model and to further explore the underlying molecular mechanisms. Seven bioactive compounds in WEU-aucubin, chlorogenic acid, geniposidic acid, quercetin, protocatechuic acid, betulin and pinoresinol diglucoside-were identified using HPLC-MS. Our results showed that WEU supplementation significantly decreased infarct volume and ameliorated neurological dysfunction in mice following MCAO/reperfusion (MCAO/R) injury. Furthermore, the administration of WEU significantly attenuated microglia activation induced by cortical ischemia in mice and inhibited the production of pro-inflammatory mediators, including interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Importantly, in contrast with the vehicle group, the protein expression levels of Toll-like receptor 4 (TLR4), phospho-p38 (p-p38) and nuclear factor kappa B (NF-κB) were reduced in the WEU group. Therefore, this present study provides evidence that E. ulmoides improves neurological behaviors by suppressing neuroinflammation and inhibiting the activation of the TLR4/ p38 MAPK and NF-κB pathways in mice after ischemia, which indicates that E.ulmoides is a promising candidate for alleviating gray matter ischemic change.

Transcriptomics study of hippocampus in mice exposed to heat stress

Heat stress (HS) triggers various pathophysiological responses in the brain, including neuroinflammation and cognitive impairments. The objective of this study was to examine the impact of HS by comparing the hippocampal transcriptomes of mice exposed to HS with those under control conditions. Our analysis revealed that HS exposure did not affect the number of SNP or InDel mutations in the mouse hippocampus, nor did it influence SNP functions, distribution, or types. However, HS did lead to differential gene expression in the hippocampus, with 210 differentially expressed genes (DEGs), including 72 upregulated and 138 downregulated genes. Gene Ontology (GO) analysis indicated that these DEGs are involved in hippocampal responses to various stimuli (chemical, oxygen-containing compounds, peptide hormones), metabolic processes (arachidonic acid, olefinic compound metabolism, lipid metabolism), and other functions. The regulation of these functions may be closely linked to specific DEGs, such as Card14, Ntrk1, Lcn2, Irs4, Cyp2c70, Hamp, Ambp, Gh, Mup19, and others, which exhibit the highest degree of differential variation. Furthermore, we observed that pre-treatment with taurine primarily modulated cognitive functions in the hippocampus following HS. Therefore, our study offers valuable insights for future research on heat stress-induced cognitive impairments and provides a theoretical foundation for developing taurine-based preventive strategies for high-risk populations.

CircRNA: A new target for ischemic stroke

Ischemic stroke, a clinical emergency and disease with a poor prognosis, has a negative impact on the survival index of patients. It is frequently precipitated by a multitude of risk factors, including trauma. Currently, there is a paucity of predictive indicators for early intervention. As stable and abundant RNA in the body, circRNAs play a regulatory role in miRNAs and proteins, which affect the occurrence and development of diseases. Moreover, circRNAs can serve as predictors of clinical diseases. Several studies have demonstrated that circRNAs play pivotal roles in numerous aspects of ischemic stroke. Consequently, circRNAs have emerged as key areas of investigation in the field of ischemic stroke.

Cell inspired delivery system equipped with natural membrane structures in applications for rescuing ischemic stroke

Ischemic stroke (IS), accounting for 87 % of stroke incidences, constitutes a paramount health challenge owing to neurological impairments and irreversible tissue damage arising from cerebral ischemia. Chief among therapeutic obstacles are the restrictive penetration of the blood-brain barrier (BBB) and insufficient targeting precision, hindering the accumulation of drugs in ischemic brain areas. Motivated by the remarkable capabilities of natural membrane-based delivery vehicles in achieving targeted delivery and traversing the BBB, thanks to their biocompatible architecture and bioactive components, numerous membrane-engineered systems such as cells, cell membranes and extracellular vesicles have emerged as promising platforms to augment IS treatment efficacy with the help of nanotechnology. This review consolidates the primary pathological manifestations following IS, elucidates the unique functionalities of natural membrane drug delivery systems (DDSs) with nanotechnology, as well as delineates the structural characteristics of various natural membranes alongside rational design strategies employed. The review illuminates both the potential and challenges encountered when employing natural membrane DDSs in IS drug therapy, offering fresh perspectives and insights for devising efficacious and practical delivery systems tailored to IS intervention.

The m6A methyltransferase METTL3 drives neuroinflammation and neurotoxicity through stabilizing BATF mRNA in microglia

Persistent neuroinflammation and progressive neuronal loss are defining features of acute brain injury including traumatic brain injury (TBI) and cerebral stroke. Microglia, the most abundant type of brain-resident immune cells, continuously surveil the environment and play a central role in shaping the inflammatory state of the central nervous system (CNS). In the study, we discovered that the protein expression of METTL3 (a m6A methyltransferase) was upregulated in inflammatory microglia independent of increased Mettl3 gene transcription following TBI in both human and mouse subjects. Subsequently, we identified TRIP12, a HECT-domain E3 ubiquitin ligase, as a negative regulator of METTL3 protein expression by facilitating METTL3 K48-linked polyubiquitination. Importantly, selective ablation of Mettl3 inhibited microglial pathogenic activities, diminished neutrophil infiltration, rescued neuronal loss and facilitated functional recovery post-TBI. Using MeRIP-seq and CUT&Tag sequencing, we identified that METTL3 promoted the expression of Basic Leucine Zipper Transcriptional Factor ATF-Like (BATF), which in turn directly bound to a cohort of characteristic inflammatory cytokines and chemokine genes. Enhanced activities of BATF in microglia elicited TNF-dependent neurotoxicity and can also promote neutrophil recruitment through releasing CXCL2. Pharmacological inhibition of METTL3 using a BBB-penetrating drug-loaded nano-system showed satisfactory therapeutic effects in both TBI and stroke mouse models. Collectively, our findings identified METTL3-m6A-BATF axis as a potential therapeutic target for terminating detrimental neuroinflammation and progressive neuronal loss following acute brain injury. METTL3 protein is significantly up-regulated in inflammatory microglia due to the decreased proteasomal degradation mediated by TRIP12 and ERK-USP5 pathways. METTL3 stabilized BATF mRNA stability and promoted BATF expression through the m6A-IGF2BP2-dependent mechanism. Elevated expression of BATF elicits a pro-inflammatory gene program in microglia, and aggravates neuroinflammatory response including local immune responses and peripheral immune cell infiltration. Genetic deletion or pharmaceutically targeting METTL3-BATF axis suppressed microglial pro-inflammatory activities and promoted neurological recovery following TBI and stroke.

Non-coding RNAs in acute ischemic stroke: from brain to periphery

Acute ischemic stroke is a clinical emergency and a condition with high morbidity, mortality, and disability. Accurate predictive, diagnostic, and prognostic biomarkers and effective therapeutic targets for acute ischemic stroke remain undetermined. With innovations in high-throughput gene sequencing analysis, many aberrantly expressed non-coding RNAs (ncRNAs) in the brain and peripheral blood after acute ischemic stroke have been found in clinical samples and experimental models. Differentially expressed ncRNAs in the post-stroke brain were demonstrated to play vital roles in pathological processes, leading to neuroprotection or deterioration, thus ncRNAs can serve as therapeutic targets in acute ischemic stroke. Moreover, distinctly expressed ncRNAs in the peripheral blood can be used as biomarkers for acute ischemic stroke prediction, diagnosis, and prognosis. In particular, ncRNAs in peripheral immune cells were recently shown to be involved in the peripheral and brain immune response after acute ischemic stroke. In this review, we consolidate the latest progress of research into the roles of ncRNAs (microRNAs, long ncRNAs, and circular RNAs) in the pathological processes of acute ischemic stroke-induced brain damage, as well as the potential of these ncRNAs to act as biomarkers for acute ischemic stroke prediction, diagnosis, and prognosis. Findings from this review will provide novel ideas for the clinical application of ncRNAs in acute ischemic stroke.

CircFndc3b Mediates Exercise-Induced Neuroprotection by Mitigating Microglial/Macrophage Pyroptosis via the ENO1/KLF2 Axis in Stroke Mice

Circular RNA (circRNA) plays a pivotal role in regulating neurological damage post-ischemic stroke. Previous researches demonstrated that exercise mitigates neurological dysfunction after ischemic stroke, yet the specific contributions of circRNAs to exercise-induced neuroprotection remain unclear. This study reveals that mmu_circ_0001113 (circFndc3b) is markedly downregulated in the penumbral cortex of a mouse model subjected to middle cerebral artery occlusion (MCAO). However, exercise increased circFndc3b expression in microglia/macrophages, alleviating pyroptosis, reducing infarct volume, and enhancing neurological recovery in MCAO mice. Mechanistically, circFndc3b interacted with Enolase 1 (ENO1), facilitating ENO1's binding to the 3' Untranslated Region (3'UTR) of Krüppel-like Factor 2 (Klf2) mRNA, thereby stabilizing Klf2 mRNA and increasing its protein expression, which suppressed NOD-like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome-mediated microglial/macrophage pyroptosis. Additionally, circFndc3b enhanced ENO1's interaction with the 3'UTR of Fused in Sarcoma (FUS) mRNA, leading to increased FUS protein levels and promoting circFndc3b cyclization. These results suggest that circFndc3b mediates exercise-induced anti-pyroptotic effects via the ENO1/Klf2 axis, and a circFndc3b/ENO1/FUS positive feedback loop may potentiate exercise's neuroprotective effects. This study unveils a novel mechanism underlying exercise-induced neuroprotection in ischemic stroke and positions circFndc3b as a promising therapeutic target for stroke management, mimicking the beneficial effects of exercise.

Fast and sensitive multivalent spatial pattern-recognition for circular RNA detection

While circular RNAs (circRNAs) exhibit lower abundance compared to corresponding linear RNAs, they demonstrate potent biological functions. Nevertheless, challenges arise from the low concentration and distinctive structural features of circRNAs, rendering existing methods operationally intricate and less sensitive. Here, we engineer an intelligent tetrahedral DNA framework (TDF) possessing precise spatial pattern-recognition properties with exceptional sensing speed and sensitivity for circRNAs. The signal output of TDF sensor occurs only when multivalent spatial pattern-recognition of a circRNA in unamplified samples. Using this sensor, we visualize the real-time response of endogenous circRNA expression in vitro neuronal cells and in vivo brain between pre-stroke and post-stroke male mice, identify the patients with acute ischemic stroke in clinical samples, as well as track the delivery of circRNA in photochromic stroked animal model. Thus, the TDF sensor provides a fast and sensitive tool for the detection of circRNA abundance in both physiological and pathophysiological conditions.

Extracellular vesicles: biological mechanisms and emerging therapeutic opportunities in neurodegenerative diseases

Extracellular vesicles (EVs) are membrane vesicles originating from different cells within the brain. The pathophysiological role of EVs in neurodegenerative diseases is progressively acknowledged. This field has advanced from basic biological research to essential clinical significance. The capacity to selectively enrich specific subsets of EVs from biofluids via distinctive surface markers has opened new avenues for molecular understandings across various tissues and organs, notably in the brain. In recent years, brain-derived EVs have been extensively investigated as biomarkers, therapeutic targets, and drug-delivery vehicles for neurodegenerative diseases. This review provides a brief overview of the characteristics and physiological functions of the various classes of EVs, focusing on the biological mechanisms by which various types of brain-derived EVs mediate the occurrence and development of neurodegenerative diseases. Concurrently, novel therapeutic approaches and challenges for the use of EVs as delivery vehicles are delineated.

Astrocyte-neuron crosstalk through extracellular vesicle-shuttled miRNA-382-5p promotes traumatic brain injury

Although astrocytes undergo functional changes in response to brain injury and may be the driving force of subsequent neuronal death, the underlying mechanisms remain incompletely elucidated. Here, we showed that extracellular vesicle (EV)-shuttled miRNA-382-5p may serve as a biomarker for the severity of traumatic brain injury (TBI), as the circulating EV-miRNA-382-5p level was significantly increased in both human patients and TBI model mice. Mechanistically, astrocyte-derived EVs delivered the shuttled miRNA-382-5p to mediate astrocyte-neuron communication, which promoted neuronal mitochondrial dysfunction by inhibiting the expression of optic atrophy-1 (OPA1). Consistent with these findings, genetic ablation of neuronal OPA1 exacerbated mitochondrial damage and neuronal apoptosis in response to TBI. Moreover, engineered RVG-miRNA-382-5p inhibitor-EVs, which can selectively deliver a miRNA-382-5p inhibitor to neurons, significantly attenuated mitochondrial damage and improved neurological function after TBI. Taken together, our data suggest that EV-shuttled miRNA-382-5p may be a critical mediator of astrocyte-induced neurotoxicity under pathological conditions and that targeting miRNA-382-5p-OPA1 signaling has potential for clinical translation in the treatment of traumatic brain injury.

Current landscape of exosomal non-coding RNAs in prostate cancer: Modulators and biomarkers

Prostate cancer (PCa) has the highest frequency of diagnosis among solid tumors and ranks second as the primary cause of cancer-related deaths. Non-coding RNAs (ncRNAs), such as microRNAs, long non-coding RNAs and circular RNAs, frequently exhibit dysregulation and substantially impact the biological behavior of PCa. Compared with circulating ncRNAs, ncRNAs loaded into exosomes are more stable because of protection by the lipid bilayer. Furthermore, exosomal ncRNAs facilitate the intercellular transfer of molecules and information. Increasing evidence suggests that exosomal ncRNAs hold promising potential in the progression, diagnosis and prognosis of PCa. This review aims to discuss the functions of exosomal ncRNAs in PCa, evaluate their possible applications as clinical biomarkers and therapeutic targets, and provide a comprehensive overview of the ncRNAs regulatory network in PCa. We also identified ncRNAs that can be utilized as biomarkers for diagnosis, staging, grading and prognosis assessment in PCa. This review offers researchers a fresh perspective on the functions of exosomal ncRNAs in PCa and provides additional options for its diagnosis, progression monitoring, and prognostic prediction.

Membrane Associated RNA-Containing Vesicles Regulate Cortical Astrocytic Microdomain Calcium Transients in Awake Ischemic Stroke Mice

Astrocytic processes minutely regulate neuronal activity via tripartite synaptic structures. The precision-tuning of the function of astrocytic processes is garnering increasing attention because of its significance in promoting brain repair following ischemic stroke. Microdomain calcium (Ca2+) transients in astrocytic processes are pivotal for the functional regulation of these processes. However, the understanding of the alterations and regulatory mechanism of microdomain Ca2+ transients during stroke remains limited. In the present study, a fast high-resolution, miniaturized two-photon microscopy is used to show that the levels of astrocytic microdomain Ca2+ transients are significantly reduced in the peri-infarct area of awake ischemic stroke mice. This finding correlated with the behavioral deficits shown by these mice under freely-moving conditions. Mitochondrial Ca2+ activity is an important factor driving the microdomain Ca2+ transients. DEAD Box 1 (DDX1) bound to circSCMH1 (a circular RNA involved in vascular post-stroke repair) facilitates the formation of membrane-associated RNA-containing vesicles (MARVs) and enhances the activity of astrocytic microdomain Ca2+ transients, thereby promoting behavioral recovery. These results show that targeting astrocytic microdomain Ca2+ transients is a potential therapeutic approach in stroke intervention.

New TIPARP inhibitor rescues mitochondrial function and brain injury in ischemic stroke

Ischemic stroke is a high-mortality disease that urgently requires new therapeutic strategies. Insufficient cerebral blood supply can induce poly (ADP-ribose) polymerase (PARP) activation and mitochondrial dysfunction, leading to tissue damage and motor dysfunction. We demonstrate that the expression of TCDD inducible PARP (TIPARP) is elevated in ischemic stroke patients and mice. Knockdown of Tiparp reduces brain infarction and promotes recovery of motor function in ischemic stroke mice. A rationally designed TIPARP inhibitor, XG-04-B1, promotes repair of brain injury and recovery of motor function in ischemic stroke mice. Mechanistically, XG-04-B1 increases neuronal plasticity and inhibits astrocyte activation in ischemic stroke mice. In addition, eukaryotic translation initiation factor 3 subunit B (EIF3B) is a direct target of TIPARP. TIPARP interacts with EIF3B through nucleoplasmic redistribution, leading to mitochondrial dysfunction. Knockdown of Tiparp and inhibition of TIPARP via XG-04-B1 restore mitochondrial homeostasis in ischemic stroke mice. Taken together, TIPARP activation contributes to mitochondrial dysfunction and subsequent brain injury, and is therefore a promising therapeutic target for stroke.

Molecular Targeting of Ischemic Stroke: The Promise of Naïve and Engineered Extracellular Vesicles

Ischemic stroke (IS) remains a leading cause of mortality and long-term disability worldwide, with limited therapeutic options available. Despite the success of early interventions, such as tissue-type plasminogen activator administration and mechanical thrombectomy, many patients continue to experience persistent neurological deficits. The pathophysiology of IS is multifaceted, encompassing excitotoxicity, oxidative and nitrosative stress, inflammation, and blood-brain barrier disruption, all of which contribute to neural cell death, further complicating the treatment of IS. Recently, extracellular vesicles (EVs) secreted naturally by various cell types have emerged as promising therapeutic agents because of their ability to facilitate selective cell-to-cell communication, neuroprotection, and tissue regeneration. Furthermore, engineered EVs, designed to enhance targeted delivery and therapeutic cargo, hold the potential to improve their therapeutic benefits by mitigating neuronal damage and promoting neurogenesis and angiogenesis. This review summarizes the characteristics of EVs, the molecular mechanisms underlying IS pathophysiology, and the emerging role of EVs in IS treatment at the molecular level. This review also explores the recent advancements in EV engineering, including the incorporation of specific proteins, RNAs, or pharmacological agents into EVs to enhance their therapeutic efficacy.

Targeted delivery of extracellular vesicles: the mechanisms, techniques and therapeutic applications

Extracellular vesicles (EVs) are cell-derived vesicles with a phospholipid bilayer measuring 50-150 nm in diameter with demonstrated therapeutic potentials. Limitations such as the natural biodistribution (mainly concentrated in the liver and spleen) and short plasma half-life of EVs present significant challenges to their clinical translation. In recent years, growing research indicated that engineered EVs with enhanced targeting to lesion sites have markedly promoted therapeutic efficacy. However, there is a dearth of systematic knowledge on the recent advances in engineering EVs for targeted delivery. Herein, we provide an overview of the targeting mechanisms, engineering techniques, and clinical translations of natural and engineered EVs in therapeutic applications. Enrichment of EVs at lesion sites may be achieved through the recognition of tissue markers, pathological changes, and the circumvention of mononuclear phagocyte system (MPS). Alternatively, external stimuli, including magnetic fields and ultrasound, may also be employed. EV engineering techniques that fulfill targeting functions includes genetic engineering, membrane fusion, chemical modification and physical modification. A comparative statistical analysis was conducted to elucidate the discrepancies between the diverse techniques on size, morphology, stability, targeting and therapeutic efficacy in vitro and in vivo. Additionally, a summary of the registered clinical trials utilizing EVs from 2010 to 2023 has been provided, with a full discussion on the perspectives. This review provides a comprehensive overview of the mechanisms and techniques associated with targeted delivery of EVs in therapeutic applications to advocate further explorations of engineered EVs and accelerate their clinical applications.

Ancestral retrovirus envelope protein ERVWE1 upregulates circ_0001810, a potential biomarker for schizophrenia, and induces neuronal mitochondrial dysfunction via activating AK2

BACKGROUND

Increasingly studies highlight the crucial role of the ancestral retrovirus envelope protein ERVWE1 in the pathogenic mechanisms of schizophrenia, a severe psychiatric disorder affecting approximately 1% of the global population. Recent studies also underscore the significance of circular RNAs (circRNAs), crucial for neurogenesis and synaptogenesis, in maintaining neuronal functions. However, the precise relationship between ERVWE1 and circRNAs in the etiology of schizophrenia remains elusive.

RESULTS

This study observed elevated levels of hsa_circ_0001810 (circ_0001810) in the blood samples of schizophrenia patients, displaying a significant positive correlation with ERVWE1 expression. Interestingly, in vivo studies demonstrated that ERVWE1 upregulated circ_0001810 in neuronal cells. Circ_0001810, acting as a competing endogenous RNA (ceRNA), bound to miR-1197 and facilitated the release of adenylate kinase 2 (AK2). The bioinformatics analysis of the schizophrenia datasets revealed increased levels of AK2 and enrichment of mitochondrial dynamics. Notably, miR-1197 was reduced in schizophrenia patients, while AK2 levels were increased. Additionally, AK2 showed positive correlations with ERVWE1 and circ_0001810. Further studies demonstrated that AK2 led to mitochondrial dysfunction, characterized by loss of intracellular ATP, mitochondrial depolarization, and disruption of mitochondrial dynamics. Our comprehensive investigation suggested that ERVWE1 influenced ATP levels, promoted mitochondrial depolarization, and disrupted mitochondrial dynamics through the circ_0001810/AK2 pathway.

CONCLUSIONS

Circ_0001810 and AK2 were increased in schizophrenia and positively correlated with ERVWE1. Importantly, ERVWE1 triggered mitochondrial dysfunction through circ_0001810/miR-1197/AK2 pathway. Recent focus on the impact of mitochondrial dynamics on schizophrenia development had led to our discovery of a novel mechanism by which ERVWE1 contributed to the etiology of schizophrenia, particularly through mitochondrial dynamics. Moreover, these findings collectively proposed that circ_0001810 might serve as a potential blood-based biomarker for schizophrenia. Consistent with our previous theories, ERVWE1 is increasingly recognized as a promising therapeutic target for schizophrenia.

CircRNA_0003307 promoted brain microvascular endothelial cell angiogenesis, invasion, and migration in cerebral ischemia-reperfusion injury: Potential involvement of miRNA-191-5p/CDK6 pathway

BACKGROUNDS

The role of miR-191-5p in cerebral ischemia-reperfusion (I/R) injury has been established, with its expression in endothelial cells demonstrating anti-angiogenic effects. A potential circular RNA, circRNA_0003307, has been identified through bioinformatics analysis as a candidate for interaction with miR-191-5p, yet its functional significance in brain I/R injury remains unexplored. We aimed to investigate whether circRNA_0003307 regulates brain microvascular endothelial cell (BMEC) vascular tube formation, invasion, and migration by regulating the miR-191-5p cascade.

METHODS

Mouse BMECs (bEnd.3) were culturedand exposed to oxygen-glucose deprivation (OGD). The effects of circRNA_0003307 on vessel-like tube formation and cellular migration were examined. In addition, we investigated the protective effects of circRNA_0003307 on I/R injury in mice.

RESULTS

The results showed the level of circRNA_0003307 was concentration-dependently increased in OGD-induced bEnd.3 cells. ODG-induction enhanced angiogenesis, migration, and invasion of bEnd.3 cells, which were further promoted by the transfection of pcDNA-0003307. Silencing circRNA_0003307 expression showed the opposite results. The dual luciferase assay demonstrated miRNA-191-5p interacted with circRNA_00033073' UTR, and miRNA-191-5p could bind with CDK6. Meanwhile, circRNA_0003307 promoted the expression of CDK6 by sponging miRNA-191-5p. The overexpression of circRNA_0003307 activated the angiogenesis, migration, and invasion of OGD-induced bEnd.3 cells, which were hindered by miRNA-191-5p mimic or siRNA-CDK6. Thus, circRNA_0003307 promoted ODG-induced angiogenesis, migration, and invasion of bEnd.3 cells by targeting miR-191-5p/CDK6 axis. In vivo, circRNA_0003307 had protective effects on brain I/R injury, including neuroprotection, anti-apoptosis and angiogenesis.

CONCLUSION

CircRNA_0003307 may be a promisingtherapeutictarget forthe treatment of cerebral I/R injury.

Macrophage exosomal miR-30c-2-3p in atherosclerotic plaques aggravates microglial neuroinflammation during large-artery atherosclerotic stroke via TGF-β/SMAD2 pathway

Circulating miR-30c-2-3p has been closely related to vascular diseases, however, its role and underlying mechanisms in ischemic stroke remained unclear. Our study addressed this gap by observing elevated levels of exosomal miR-30c-2-3p in patients with acute ischemic stroke due to large artery atherosclerosis. Further investigation revealed that these exosomal miR-30c-2-3p primarily originated from macrophages within atherosclerotic plaques, exacerbating ischemic stroke by targeting microglia. Exosomes enriched with miR-30c-2-3p increased microglial inflammatory properties in vivo and aggravated neuroinflammation by inhibiting SMAD2. In summary, our findings revealed a novel mechanism whereby macrophage-derived foam cells within atherosclerotic plaques secrete exosomes with high levels of miR-30c-2-3p, thus aggravate brain damage during ischemic stroke, which serves as crucial link between the periphery and brain.

Controlling Circular RNA Encapsulation within Extracellular Vesicles for Gene Editing and Protein Replacement

Extracellular vesicles (EVs) are a population of vesicular bodies originating from cells, and EVs have been proven to have the potential to deliver different cargos, such as RNAs. However, conventional methods are not able to encapsulate long RNAs into EVs efficiently or may compromise the integrity of EVs. In this study, we have devised a strategy to encapsulate long circRNAs (>1000 nt) into EVs by harnessing the sorting mechanisms of cells. This strategy utilizes the inherent richness of circular RNAs in EVs and a genetic engineering method to increase the cytoplasmic concentration of target circRNAs, facilitating highly efficient RNA back-splicing to drive the circularization of RNAs. This allows target circRNAs to load into EVs with high efficiency. Furthermore, we demonstrate the practical applications of this strategy, showing that these circRNAs can be delivered by EVs to recipient cells for protein expression and to mice for gene editing.

Synthetic circRNA therapeutics: innovations, strategies, and future horizons

Small molecule drugs are increasingly emerging as innovative and effective treatments for various diseases, with mRNA therapeutics being a notable representative. The success of COVID-19 vaccines has underscored the transformative potential of mRNA in RNA therapeutics. Within the RNA family, there is another unique type known as circRNA. This single-stranded closed-loop RNA molecule offers notable advantages over mRNA, including enhanced stability and prolonged protein expression, which may significantly impact therapeutic strategies. Furthermore, circRNA plays a pivotal role in the pathogenesis of various diseases, such as cancers, autoimmune disorders, and cardiovascular diseases, making it a promising clinical intervention target. Despite these benefits, the application of circRNA in clinical settings remains underexplored. This review provides a comprehensive overview of the current state of synthetic circRNA therapeutics, focusing on its synthesis, optimization, delivery, and diverse applications. It also addresses the challenges impeding the advancement of circRNA therapeutics from bench to bedside. By summarizing these aspects, the review aims to equip researchers with insights into the ongoing developments and future directions in circRNA therapeutics. Highlighting both the progress and the existing gaps in circRNA research, this review offers valuable perspectives for advancing the field and guiding future investigations.

Exosomes as Vehicles for Noncoding RNA in Modulating Inflammation: A Promising Regulatory Approach for Ischemic Stroke and Myocardial Infarction

Exosomes have grown as promising carriers for noncoding RNAs (ncRNAs) in the treatment of inflammation, particularly in conditions like ischemic stroke and myocardial infarction. These ncRNAs, which include microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), play a crucial role in regulating inflammatory pathways, presenting new therapeutic opportunities. In both ischemic stroke and myocardial infarction, inflammation significantly influences disease progression and severity. Exosomes can deliver ncRNAs directly to specific cells and tissues, providing a targeted approach to modulate gene expression and reduce inflammation. Their biocompatibility and low risk of inducing immune responses make exosomes ideal therapeutic vehicles. Ongoing research is focused on optimizing the loading of ncRNAs into exosomes, ensuring efficient delivery, and understanding the mechanisms by which these ncRNAs mitigate inflammation. In ischemic stroke, exosome-derived ncRNAs originate from various cell types, including neurons, M2 microglia, patient serum, genetically engineered HEK293T cells, and mesenchymal stromal cells. In the case of myocardial infarction, these ncRNAs are sourced from mesenchymal stem cells, endothelial cells, and patient plasma. These exosome-loaded ncRNAs play a significant role in modulating inflammation in both ischemic stroke and myocardial infarction. As this research advances, therapies based on exosomes may completely change how diseases linked to inflammation are treated, offering new avenues for patient care and recovery. This review explores the latest advancements in understanding how exosomes impact specific inflammatory components, with a particular emphasis on the role of ncRNAs contained in exosomes. The review concludes by highlighting the clinical potential of exosome-derived ncRNAs as innovative therapeutic and diagnostic tools.

Superenhancer-driven circRNA Myst4 involves in pulmonary artery smooth muscle cell ferroptosis in pulmonary hypertension

The abnormal expression of circular RNAs (circRNAs) is emerging as a critical cause in regulation of pathological changes of hypoxic pulmonary hypertension (PH), in which ferroptosis is a new pathological change reported recently. However, how circRNAs regulate ferroptosis remains unclear. Here, we proved a significant decrease in circMyst4 expression in hypoxia. In vitro assays revealed that circMyst4 alleviated hypoxic pulmonary artery smooth muscle cell (PASMC) ferroptosis through directly combing with DDX5 in the nucleus to promote GPX4 mRNA processing and inhibiting the formation of the Eef1a1/ACSL4 complex in the cytoplasm. Additionally, superenhancer (SE) was verified to drive the generation of circMyst4. In vivo assays revealed that circMyst4 inhibited the progression of hypoxic PH. Overall, SE-driven circMyst4 may be a new potential therapeutic target for mediating PASMC ferroptosis through promoting DDX5-regulated GPX4 mRNA processing and inhibiting the binding between Eef1a1 and ACSL4.

Curcumin loaded hydrogel with double ROS-scavenging effect regulates microglia polarization to promote poststroke rehabilitation

Cyclodextrins are used to include curcumin to form complex, which is subsequently loaded into a reactive oxygen species (ROS) responsive hydrogel (Cur gel). This gel exhibits a dual ROS scavenging effect. The gel can neutralize extracellular ROS to lead to a ROS-sensitive curcumin release. The released curcumin complex can eliminate intracellular ROS. Furthermore, the Cur gel effectively downregulates the expression of CD16 and IL-1β while upregulating CD206 and TGF-β in oxygen and glucose-deprived (OGD) BV2 cells. Additionally, it restores the expression of synaptophysin and PSD95 in OGD N2a cells. Upon injection into the stroke cavity, the Cur gel reduces CD16 expression and increases CD206 expression in the peri-infarct area of stroke mice, indicating an in vivo anti-inflammatory polarization of microglia. Colocalization studies using PSD95 and VGlut-1 stains, along with Golgi staining, reveal enhanced neuroplasticity. As a result, stroke mice treated with the Cur gel exhibit the most significant motor function recovery. Mechanistic investigations demonstrate that the released curcumin complex scavenges ROS and suppresses the activation of the ROS-NF-κB signaling pathway by inhibiting the translocation of p47-phox and p67-phox to lead to anti-inflammatory microglia polarization. Consequently, the Cur gel exhibits promising potential for promoting post-stroke rehabilitation in clinics.

A systematic review and in silico analysis of studies investigating the ischemic penumbra proteome in animal models of experimental stroke

Ischaemic stroke results in the formation of a cerebral infarction bordered by an ischaemic penumbra. Characterising the proteins within the ischaemic penumbra may identify neuro-protective targets and novel circulating markers to improve patient care. This review assessed data from studies using proteomic platforms to compare ischaemic penumbra tissues to controls following experimental stroke in animal models. Proteins reported to differ significantly between penumbra and control tissues were analysed in silico to identify protein-protein interactions and over-represented pathways. Sixteen studies using rat (n = 12), mouse (n = 2) or primate (n = 2) models were included. Heterogeneity in the design of the studies and definition of the penumbra were observed. Analyses showed high abundance of p53 in the penumbra within 24 hours of permanent ischaemic stroke and was implicated in driving apoptosis, cell cycle progression, and ATM- MAPK- and p53- signalling. Between 1 and 7 days after stroke there were changes in the abundance of proteins involved in the complement and coagulation pathways. Favourable recovery 1 month after stroke was associated with an increase in the abundance of proteins involved in wound healing. Poor recovery was associated with increases in prostaglandin signalling. Findings suggest that p53 may be a target for novel therapeutics for ischaemic stroke.

The Role of circHIPK3 in Tumorigenesis and Its Potential as a Biomarker in Lung Cancer

Lung cancer treatment and detection can be improved by the identification of new biomarkers. Novel approaches in investigating circular RNAs (circRNAs) as biomarkers have yielded promising results. A circRNA molecule circHIPK3 was found to be widely expressed in non-small-cell lung cancer (NSCLC) cells, where it plays a crucial role in lung cancer tumorigenesis. CircHIPK3 promotes lung cancer progression by sponging oncosuppressive miRNAs such as miR-124, miR-381-3p, miR-149, and miR-107, which results in increased cell proliferation, migration, and resistance to therapies. Inhibiting circHIPK3 has been demonstrated to suppress tumour growth and induce apoptosis, which suggests its potential use in the development of new lung cancer treatment strategies targeting circHIPK3-related pathways. As a biomarker, circHIPK3 shows promise for early detection and monitoring of lung cancer. CircHIPK3 increased expression levels in lung cancer cells, and its potential link to metastasis risk highlights its clinical relevance. Given the promising preliminary findings, more clinical trials are needed to validate circHIPK3 efficacy as a biomarker. Moreover, future research should determine if the mechanisms discovered in NSCLC apply to small cell lung cancer (SCLC) to investigate circHIPK3-targeted therapies for SCLC.

Body fluid multiomics in 3PM-guided ischemic stroke management: health risk assessment, targeted protection against health-to-disease transition, and cost-effective personalized approach are envisaged

Because of its rapid progression and frequently poor prognosis, stroke is the third major cause of death in Europe and the first one in China. Many independent studies demonstrated sufficient space for prevention interventions in the primary care of ischemic stroke defined as the most cost-effective protection of vulnerable subpopulations against health-to-disease transition. Although several studies identified molecular patterns specific for IS in body fluids, none of these approaches has yet been incorporated into IS treatment guidelines. The advantages and disadvantages of individual body fluids are thoroughly analyzed throughout the paper. For example, multiomics based on a minimally invasive approach utilizing blood and its components is recommended for real-time monitoring, due to the particularly high level of dynamics of the blood as a body system. On the other hand, tear fluid as a more stable system is recommended for a non-invasive and patient-friendly holistic approach appropriate for health risk assessment and innovative screening programs in cost-effective IS management. This article details aspects essential to promote the practical implementation of highlighted achievements in 3PM-guided IS management.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00376-2.

Physical exercise-induced circAnks1b upregulation promotes protective endoplasmic reticulum stress and suppresses apoptosis via miR-130b-5p/Pak2 signaling in an ischemic stroke model

AIMS

Physical exercise (PE) can accelerate post-stroke recovery. This study investigated contributions of circRNAs to PE-induced improvements in post-stroke neurological function.

METHODS

Rats subjected to transient middle cerebral artery occlusion were left sedentary or provided running-wheel access for 4 weeks during recovery. CircRNAs from peri-infarct cortex were identified by high-throughput sequencing, and interactions with miRNAs by immunoprecipitation, fluorescence in suit hybridization, and dual-luciferase reporter assays. In vivo circRNA knockdown was achieved using shRNA-AAVs and in vitro overexpression by plasmid transfection. Transmission electron microscopy, western blotting, and TUNEL assays were conducted to explore circRNA contributions to endoplasmic reticulum (ER) stress and neuronal apoptosis. CircRNA levels were measured in plasma from stroke patients by qRT-PCR and associations with neurological scores assessed by Pearson's correlation analysis.

RESULTS

PE upregulated circAnks1b, reduced infarct volume, and mitigated neurological dysfunction, while circAnks1b knockdown exacerbated neurological dysfunction and increased infarct size despite PE. CircAnks1b sponged miR-130b-5p, thereby disinhibiting Pak2 expression. Conversely, Pak2 downregulation disrupted PE-mediated protective ER stress, leading to reduced IRE1/XBP1 and heightened apoptosis. Plasma circAnks1b was higher in stroke patients receiving PE than sedentary patients and correlated negatively with neurological scores.

CONCLUSIONS

CircAnks1b upregulation may be an effective therapeutic strategy for post-stroke recovery.

Circular RNA as a Biomarker for Diagnosis, Prognosis and Therapeutic Target in Acute and Chronic Lymphoid Leukemia

Circular RNAs (circRNAs) are single-stranded RNAs that have received much attention in recent years. CircRNAs lack a 5' head and a 3' poly-A tail. The structure of this type of RNAs make them resistant to digestion by exonucleases. CircRNAs are expressed in different cells and have various functions. The function of circRNAs is done by sponging miRNAs, changing gene expression, and protein production. The expression of circRNAs changes in different types of cancers, which causes changes in cell growth, proliferation, differentiation, and apoptosis. Changes in the expression of circRNAs can cause the invasion and progression of tumors. Studies have shown that changes in the expression of circRNAs can be seen in acute lymphoid leukemia (ALL) and chronic lymphoid leukemia (CLL). The conducted studies aim to identify circRNAs whose expression has changed in these leukemias and their more precise function so that these circRNAs can be identified as biomarkers, prediction of patient prognosis, and treatment targets for ALL and CLL patients. In this study, we review the studies conducted on the role and function of circRNAs in ALL and CLL patients. The results of the studies show that there is a possibility of using circRNAs as biomarkers in the identification and treatment of patients in the future.