FSAP aggravated endothelial dysfunction and neurological deficits in acute ischemic stroke due to large vessel occlusion

Microglia-mediated endothelial protection: the role of SHPL-49 in ischemic stroke

It was previously shown that SHPL-49, a glycoside derivative of salidroside formed through structural modification, exhibited neuroprotective effects in a rat cerebral ischemia model of permanent middle cerebral artery occlusion (pMCAO). Additionally, SHPL-49 enhanced the mRNA expression of vascular endothelial growth factor-a (Vegf-a) in macrophages. Microglia, functioning as resident macrophages within the brain, promptly respond to cerebral ischemia and engage in interactions with the cells of the Glial-Vascular Unit to orchestrate nerve injury responses. We postulated that the neuroprotective effects of SHPL-49 were mediated through microglia-dependent amelioration of endothelial dysfunction following cerebral ischemia. The present study demonstrates that SHPL-49 effectively mitigated microglia-dependent endothelial dysfunction in the pMCAO model by upregulating the expression of VEGF and suppressing the release of MMP-9 from microglia. Further MRI analyses confirmed that SHPL-49 significantly reduced nerve and endothelial function when microglia were depleted in the brains of pMCAO rats. The above phenomenon was also confirmed in the in vitro experiment investigating microglia-mediated brain endothelial cell function. Furthermore, we discovered that SHPL-49 activates the VEGFR2/Akt/eNOS pathways in endothelial cells and suppresses the p38 MAPK/MMP-9 pathways in microglia cells, thereby facilitating brain endothelial cell protection. Altogether, we have demonstrated that SHPL-49 effectively ameliorates endothelial dysfunction induced by cerebral ischemia through a microglia-dependent mechanism, thereby providing more valuable insights and references for the clinical evaluation of SHPL-49 injection for ischemic stroke.

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.

Bruton's tyrosine kinase inhibition ameliorated neuroinflammation during chronic white matter ischemia

Chronic cerebral hypoperfusion (CCH), a disease afflicting numerous individuals worldwide, is a primary cause of cognitive deficits, the pathogenesis of which remains poorly understood. Bruton's tyrosine kinase inhibition (BTKi) is considered a promising strategy to regulate inflammatory responses within the brain, a crucial process that is assumed to drive ischemic demyelination progression. However, the potential role of BTKi in CCH has not been investigated so far. In the present study, we elucidated potential therapeutic roles of BTK in both in vitro hypoxia and in vivo ischemic demyelination model. We found that cerebral hypoperfusion induced white matter injury, cognitive impairments, microglial BTK activation, along with a series of microglia responses associated with inflammation, oxidative stress, mitochondrial dysfunction, and ferroptosis. Tolebrutinib treatment suppressed both the activation of microglia and microglial BTK expression. Meanwhile, microglia-related inflammation and ferroptosis processes were attenuated evidently, contributing to lower levels of disease severity. Taken together, BTKi ameliorated white matter injury and cognitive impairments induced by CCH, possibly via skewing microglia polarization towards anti-inflammatory and homeostatic phenotypes, as well as decreasing microglial oxidative stress damage and ferroptosis, which exhibits promising therapeutic potential in chronic cerebral hypoperfusion-induced demyelination.

Adenylyl cyclase 2 expression and function in neurological diseases

Adenylyl cyclases (Adcys) catalyze the formation of cAMP, a secondary messenger essential for cell survival and neurotransmission pathways in the CNS. Adcy2, one of ten Adcy isoforms, is highly expressed in the CNS. Abnormal Adcy2 expression and mutations have been reported in various neurological disorders in both rodents and humans. However, due to the lack of genetic tools, loss-of-function studies of Adcy2 are scarce. In this review, we summarize recent findings on Adcy2 expression and function in neurological diseases. Specifically, we first introduce the biochemistry, structure, and function of Adcy2 briefly. Next, the expression and association of Adcy2 in human patients and rodent models of neurodegenerative diseases (Alzheimer's disease and Parkinson's disease), psychiatric disorders (Tourette syndrome, schizophrenia, and bipolar disorder), and other neurological conditions (stress-associated disorders, stroke, epilepsy, and Lesch-Nyhan Syndrome) are elaborated. Furthermore, we discuss the pros and cons of current studies as well as key questions that need to be answered in the future. We hope to provide a focused review on Adcy2 that promotes future research in the field.

Developing targeted antioxidant nanomedicines for ischemic penumbra: Novel strategies in treating brain ischemia-reperfusion injury

During cerebral ischemia-reperfusion conditions, the excessive reactive oxygen species in the ischemic penumbra region, resulting in neuronal oxidative stress, constitute the main pathological mechanism behind ischemia-reperfusion damage. Swiftly reinstating blood perfusion in the ischemic penumbra zone and suppressing neuronal oxidative injury are key to effective treatment. Presently, antioxidants in clinical use suffer from low bioavailability, a singular mechanism of action, and substantial side effects, severely restricting their therapeutic impact and widespread clinical usage. Recently, nanomedicines, owing to their controllable size and shape and surface modifiability, have demonstrated good application potential in biomedicine, potentially breaking through the bottleneck in developing neuroprotective drugs for ischemic strokes. This manuscript intends to clarify the mechanisms of cerebral ischemia-reperfusion injury and provides a comprehensive review of the design and synthesis of antioxidant nanomedicines, their action mechanisms and applications in reversing neuronal oxidative damage, thus presenting novel approaches for ischemic stroke prevention and treatment.

Acupuncture Extended the Thrombolysis Window by Suppressing Blood-Brain Barrier Disruption and Regulating Autophagy-Apoptosis Balance after Ischemic Stroke

BACKGROUND

Ischemic stroke (IS) is one of the leading causes of death and disability worldwide. The narrow therapeutic window (within 4.5 h) and severe hemorrhagic potential limits therapeutic efficacy of recombinant tissue type plasminogen activator (rt-PA) intravenous thrombolysis for patients. Xingnao Kaiqiao (XNKQ) acupuncture is an integral part of traditional Chinese medicine, specifically designed to address acute ischemic stroke by targeting key acupoints such as Shuigou (GV26) and Neiguan (PC6). In this study, we explored the therapeutic potential of XNKQ acupuncture in extending the time window for thrombolysis and interrogated the molecular mechanisms responsible for this effect.

METHODS

The effect of extending the thrombolysis window by acupuncture was evaluated via TTC staining, neuronal score evaluation, hemorrhagic transformation assay, and H&E staining. RNA sequencing (RNA-seq) technology was performed to identify the therapeutic targets and intervention mechanisms of acupuncture. Evans blue staining and transmission electron microscopy were used to assess blood-brain barrier (BBB) integrity. Immunofluorescence staining and co-immunoprecipitation were performed to evaluate the level of autophagy and apoptosis and validate their interactions with BBB endothelial cells.

RESULTS

Acupuncture alleviated infarction and neurological deficits and extended the thrombolysis window to 6 h. The RNA-seq revealed 16 potential therapeutic predictors for acupuncture intervention, which related to suppressing inflammation and restoring the function of BBB and blood vessels. Furthermore, acupuncture suppressed BBB leakage and preserved tight junction protein expression. The protective effect was associated with regulation of the autophagy-apoptosis balance in BBB endothelial cells. Acupuncture intervention dissociated the Beclin1/Bcl-2 complex, thereby promoting autophagy and reducing apoptosis.

CONCLUSION

XNKQ acupuncture could serve as an adjunctive therapy for rt-PA thrombolysis, aiming to extend the therapeutic time window and mitigate ischemia-reperfusion injury. Acupuncture suppressed BBB disruption by regulating the autophagy-apoptosis balance, which in turn extended the therapeutic window of rt-PA in IS. These findings provide a rationale for further exploration of acupuncture as a complementary candidate co-administered with rt-PA.

Dynamic Changes and Clinical Significance of Plasma Galectin-3 in Patients with Acute Ischemic Stroke Undergoing Endovascular Therapy

Purpose

Galectin-3 is a key regulator of microglial proliferation and activation and may have dual and time-dependent effects on ischemic stroke. This study aimed to prospectively investigate the dynamic changes in Galectin-3 levels in patients with acute ischemic stroke receiving endovascular therapy and its clinical significance.

Patients and Methods

A total of 105 patients with acute ischemic stroke who underwent endovascular therapy were prospectively enrolled. Plasma Galectin-3 was quantitatively detected by an enzyme-linked immunosorbent assay before the operation and at 1 day, 3 days and 7 days after the operation. A linear mixed-effect model, Pearson correlation analysis and receiver operating characteristic (ROC) curve analysis were used to evaluate the dynamic changes in the plasma Galectin-3 concentration and its relationship with clinical outcomes.

Results

Increases in plasma Galectin-3 levels at 1 day and 3 days after surgery were associated with early neurological deterioration and death (both P <0.05). Increased Galectin-3 levels before surgery and at 1 day and 3 days after surgery were associated with poor prognosis (P <0.05). Pearson correlation analysis revealed that Galectin-3 levels before surgery (r =0.318, P =0.002), at 1 day (r =0.318, P =0.001), 3 days (r =0.429, P < 0.001) and 7 days after surgery (r =0.340, P =0.001) were positively correlated with NIHSS scores. The ROC curve results showed that Galectin-3 concentration had a certain predictive value for death at 1 day (AUC=0.707, P=0.013), 3 days (AUC=0.708, P=0.016) and 7 days after the operation (AUC=0.708, P=0.016), but this predictive value was lower than that of the NIHSS score.

Conclusion

In acute ischemic stroke patients receiving endovascular therapy, an increase in the plasma Galectin-3 levels were associated with death, poor prognosis, and early neurological deterioration. Galectin-3 levels were significantly correlated with the NIHSS score and had a certain predictive value for death.

TREM2-IGF1 Mediated Glucometabolic Enhancement Underlies Microglial Neuroprotective Properties During Ischemic Stroke

Microglia, the major resident immune cells in the central nervous system, serve as the frontline soldiers against cerebral ischemic injuries, possibly along with metabolic alterations. However, signaling pathways involved in the regulation of microglial immunometabolism in ischemic stroke remain to be further elucidated. In this study, using single-nuclei RNA sequencing, a microglial subcluster up-regulated in ischemic brain tissues is identified, with high expression of Igf1 and Trem2, neuroprotective transcriptional signature and enhanced oxidative phosphorylation. Microglial depletion by PLX3397 exacerbates ischemic brain damage, which is reversed by repopulating the microglia with high Igf1 and Trem2 phenotype. Mechanistically, Igf1 serves as one of the major down-stream molecules of Trem2, and Trem2-Igf1 signaling axis regulates microglial functional and metabolic profiles, exerting neuroprotective effects on ischemic stroke. Overexpression of Igf1 and supplementation of cyclocreatine restore microglial glucometabolic levels and cellular functions even in the absence of Trem2. These findings suggest that Trem2-Igf1 signaling axis reprograms microglial immunometabolic profiles and shifts microglia toward a neuroprotective phenotype, which has promising therapeutic potential in treating ischemic stroke.

N6-methyladenosine modification in ischemic stroke: Functions, regulation, and therapeutic potential

N6-methyladenosine (m6A) modification is the most frequently occurring internal modification in eukaryotic RNAs. By modulating various aspects of the RNA life cycle, it has been implicated in a wide range of pathological and physiological processes associated with human diseases. Ischemic stroke is a major cause of death and disability worldwide with few treatment options and a narrow therapeutic window, and accumulating evidence has indicated the involvement of m6A modifications in the development and progression of this type of stroke. In this review, which provides insights for the prevention and clinical treatment of stroke, we present an overview of the roles played by m6A modification in ischemic stroke from three main perspectives: (1) the association of m6A modification with established risk factors for stroke, including hypertension, diabetes mellitus, hyperlipidemia, obesity, and heart disease; (2) the roles of m6A modification regulators and their functional regulation in the pathophysiological injury mechanisms of stroke, namely oxidative stress, mitochondrial dysfunction, endothelial dysfunction, neuroinflammation, and cell death processes; and (3) the diagnostic and therapeutic potential of m6A regulators in the treatment of stroke.

Knowledge structure and global trends of machine learning in stroke over the past decade: A scientometric analysis

Objective

Machine learning (ML) models have been widely applied in stroke prediction, diagnosis, treatment, and prognosis assessment. We aimed to conduct a comprehensive scientometrics analysis of studies related to ML in stroke and reveal its current status, knowledge structure, and global trends.

Methods

All documents related to ML in stroke were retrieved from the Web of Science database on March 15, 2023. We refined the documents by including only original articles and reviews in the English language. The literature published over the past decade was imported into scientometrics software for influence detection and collaborative network analysis.

Results

2389 related publications were included. The annual publication outputs demonstrated explosive growth, with an average growth rate of 63.99 %. Among the 90 countries/regions involved, the United States (729 articles) and China (636 articles) were the most productive countries. Frontiers in Neurology was the most prolific journal with 94 articles. 234 highly cited articles, each with more than 31 citations, were detected. Keyword analysis revealed a total of 5333 keywords, with a predominant focus on the application of ML models in the early diagnosis, classification, and prediction of "acute ischemic stroke" and "atrial fibrillation-related stroke". The keyword "classification" had the first and longest burst, spanning from 2013 to 2018. 'Upport vector machine' got the strongest burst strength with 6.2. Keywords such as 'mechanical thrombectomy', 'expression', and 'prognosis' experienced bursts in 2022 and have continued to be prominent.

Conclusion

The applications of ML in stroke are increasingly diverse and extensive, with researchers showing growing interest over the past decade. However, the clinical application of ML in stroke is still in its early stages, and several limitations and challenges need to be addressed for its widespread adoption in clinical practice.

Pathogenic mechanisms and therapeutic implications of extracellular matrix remodelling in cerebral vasospasm

Cerebral vasospasm significantly contributes to poor prognosis and mortality in patients with aneurysmal subarachnoid hemorrhage. Current research indicates that the pathological and physiological mechanisms of cerebral vasospasm may be attributed to the exposure of blood vessels to toxic substances, such as oxyhaemoglobin and inflammation factors. These factors disrupt cerebral vascular homeostasis. Vascular homeostasis is maintained by the extracellular matrix (ECM) and related cell surface receptors, such as integrins, characterised by collagen deposition, collagen crosslinking, and elastin degradation within the vascular ECM. It involves interactions between the ECM and smooth muscle cells as well as endothelial cells. Its biological activities are particularly crucial in the context of cerebral vasospasm. Therefore, regulating ECM homeostasis may represent a novel therapeutic target for cerebral vasospasm. This review explores the potential pathogenic mechanisms of cerebral vasospasm and the impacts of ECM protein metabolism on the vascular wall during ECM remodelling. Additionally, we underscore the significance of an ECM protein imbalance, which can lead to increased ECM stiffness and activation of the YAP pathway, resulting in vascular remodelling. Lastly, we discuss future research directions.

Factor VII Activating Protease (FSAP) and Its Importance in Hemostasis—Part I: FSAP Structure, Synthesis and Activity Regulation: A Narrative Review

Factor VII activating protease (FSAP) was first isolated from human plasma less than 30 years ago. Since then, many research groups have described the biological properties of this protease and its role in hemostasis and other processes in humans and other animals. With the progress of knowledge about the structure of FSAP, several of its relationships with other proteins or chemical compounds that may modulate its activity have been explained. These mutual axes are described in the present narrative review. The first part of our series of manuscripts on FSAP describes the structure of this protein and the processes leading to the enhancement and inhibition of its activities. The following parts, II and III, concern the role of FSAP in hemostasis and in the pathophysiology of human diseases, with particular emphasis on cardiovascular diseases.

Nanoparticle and Stem Cell Combination Therapy for the Management of Stroke

Stroke is currently one of the primary causes of morbidity and mortality worldwide. Unfortunately, the available treatments for stroke are still extremely limited. Indeed, stem cell (SC) therapy is a new option for the treatment of stroke that could significantly expand the therapeutic time window of stroke. Some proposed mechanisms for stroke-based SC therapy are the incorporation of SCs into the host brain to replace dead or damaged cells/tissues. Moreover, acute cell delivery can inhibit apoptosis and decrease lesion size, providing immunomudolatory and neuroprotection effects. However, several major SC problems related to SCs such as homing, viability, uncontrolled differentiation, and possible immune response, have limited SC therapy. A combination of SC therapy with nanoparticles (NPs) can be a solution to address these challenges. NPs have received considerable attention in regulating and controlling the behavior of SCs because of their unique physicochemical properties. By reviewing the pathophysiology of stroke and the therapeutic benefits of SCs and NPs, we hypothesize that combined therapy will offer a promising future in the field of stroke management. In this work, we discuss recent literature in SC research combined with NP-based strategies that may have a synergistic outcome after stroke incidence.

Molecular Mechanism of Epimedium Extract against Ischemic Stroke Based on Network Pharmacology and Experimental Validation

Ischemic stroke exhibits high morbidity, disability, and mortality, and treatments for ischemic stroke are limited despite intensive research. The potent neuroprotective benefits of Epimedium against ischemic stroke have gained lots of interest. Nevertheless, systematic research on the direct role and mechanisms of Epimedium in ischemic stroke is still lacking. Network pharmacology analysis coupled with experimental verification was utilized to systematically evaluate the potential pharmacological mechanism of Epimedium against ischemic stroke. The TCMSP database was used to mine the bioactive ingredients and Epimedium's targets. The DrugBank, OMIM, and GeneCards databases were employed to identify potential targets of ischemic stroke. GO and KEGG pathway analyses were also carried out. The interaction between active components and hub targets was confirmed via molecular docking. An experimental ischemic stroke model was used to evaluate the possible therapeutic mechanism of Epimedium. As a result, 23 bioactive compounds of Epimedium were selected, and 30 hub targets of Epimedium in its function against ischemic stroke were identified, and molecular docking results demonstrated good binding. The IL-17 signaling pathway was revealed as a potentially significant pathway, with the NF-κB and MAPK/ERK signaling pathways being involved. Furthermore, in vivo experiments demonstrated that Epimedium treatment could improve neurological function and reduce infarct volume. Additionally, Epimedium reduced the activation of microglia and astrocytes in both the ischemic penumbra of the hippocampus and cerebral cortex following ischemic stroke. Western blot and RT-qPCR analyses demonstrated that Epimedium not only depressed the expression of IL-1β, TNF-α, IL-6, and IL-4 but also inhibited the NF-κB and MAPK/ERK signaling pathways. This study applied network pharmacology and in vivo experiment to explore possible mechanism of Epimedium's role against ischemic stroke, which provides insight into the treatment of ischemic stroke.

Factor VII activating protease (FSAP) inhibits the outcome of ischemic stroke in mouse models

The outcome of ischemic stroke can be improved by further refinements of thrombolysis and reperfusion strategies. Factor VII activating protease (FSAP) is a circulating serine protease that could be important in this context. Its levels are raised in patients as well as mice after stroke and a single nucleotide polymorphism (SNP) in the coding sequence, which results in an inactive enzyme, is linked to an increased risk of stroke. In vitro, FSAP cleaves fibrinogen to promote fibrinolysis, activates protease-activated receptors, and decreases the cellular cytotoxicity of histones. Based on these facts, we hypothesized that FSAP can be used as a treatment for ischemic stroke. A combination of tissue plasminogen activator (tPA), a thrombolytic drug, and recombinant serine protease domain of FSAP (FSAP-SPD) improved regional cerebral perfusion and neurological outcome and reduced infarct size in a mouse model of thromboembolic stroke. FSAP-SPD also improved stroke outcomes and diminished the negative consequences of co-treatment with tPA in the transient middle cerebral artery occlusion model of stroke without altering cerebral perfusion. The inactive MI-isoform of FSAP had no impact in either model. FSAP enhanced the lysis of blood clots in vitro, but in the tail transection model of hemostasis, FSAP-SPD treatment provoked a faster clotting time indicating that it also has pro-coagulant actions. Thus, apart from enhancing thrombolysis, FSAP has multiple effects on stroke progression and represents a promising novel therapeutic strategy in the treatment of ischemic stroke.

Identification of a Phage Display-Derived Peptide Interacting with the N-Terminal Region of Factor VII Activating Protease (FSAP) Enables Characterization of Zymogen Activation

Factor VII Activating protease (FSAP) has a protective effect in diverse disease conditions as inferred from studies in FSAP-/- mice and humans deficient in FSAP activity due to single-nucleotide polymorphism. The zymogen form of FSAP in plasma is activated by extracellular histones that are released during tissue injury or inflammation or by positively charged surfaces. However, it is not clear whether this activation mechanism is specific and amenable to manipulation. Using a phage display approach, we have identified a Cys-constrained 11 amino acid peptide, NNKC9/41, that activates pro-FSAP in plasma. The synthetic linear peptide has a propensity to cyclize through the terminal Cys groups, of which the antiparallel cyclic dimer, but not the monocyclic peptide, is the active component. Other commonly found zymogens in the plasma, related to the hemostasis system, were not activated. Binding studies with FSAP domain deletion mutants indicate that the N-terminus of FSAP is the key interaction site of this peptide. In a monoclonal antibody screen, we identified MA-FSAP-38C7 that prevented the activation of pro-FSAP by the peptide. This antibody bound to the LESLDP sequence (amino acids 30-35) in an intrinsically disordered stretch in the N-terminus of FSAP. The plasma clotting time was shortened by NNKC9/41, and this was reversed by MA-FSAP-38C7, demonstrating the utility of this peptide. Peptide NNKC9/41 will be useful as a tool to delineate the molecular mechanism of activation of pro-FSAP, elucidate its biological role, and provide a starting point for the pharmacological manipulation of FSAP activity.