Neuroinflammation in Cerebral Ischemia and Ischemia/Reperfusion Injuries: From Pathophysiology to Therapeutic Strategies

Overexpression of low-density lipoprotein receptor prevents neurotoxic polarization of astrocytes via inhibiting NLRP3 inflammasome activation in experimental ischemic stroke

JOURNAL/nrgr/04.03/01300535-202502000-00027/figure1/v/2024-05-28T214302Z/r/image-tiff Neurotoxic astrocytes are a promising therapeutic target for the attenuation of cerebral ischemia/reperfusion injury. Low-density lipoprotein receptor, a classic cholesterol regulatory receptor, has been found to inhibit NLR family pyrin domain containing protein 3 (NLRP3) inflammasome activation in neurons following ischemic stroke and to suppress the activation of microglia and astrocytes in individuals with Alzheimer's disease. However, little is known about the effects of low-density lipoprotein receptor on astrocytic activation in ischemic stroke. To address this issue in the present study, we examined the mechanisms by which low-density lipoprotein receptor regulates astrocytic polarization in ischemic stroke models. First, we examined low-density lipoprotein receptor expression in astrocytes via immunofluorescence staining and western blotting analysis. We observed significant downregulation of low-density lipoprotein receptor following middle cerebral artery occlusion reperfusion and oxygen-glucose deprivation/reoxygenation. Second, we induced the astrocyte-specific overexpression of low-density lipoprotein receptor using astrocyte-specific adeno-associated virus. Low-density lipoprotein receptor overexpression in astrocytes improved neurological outcomes in middle cerebral artery occlusion mice and reversed neurotoxic astrocytes to create a neuroprotective phenotype. Finally, we found that the overexpression of low-density lipoprotein receptor inhibited NLRP3 inflammasome activation in oxygen-glucose deprivation/reoxygenation injured astrocytes and that the addition of nigericin, an NLRP3 agonist, restored the neurotoxic astrocyte phenotype. These findings suggest that low-density lipoprotein receptor could inhibit the NLRP3-meidiated neurotoxic polarization of astrocytes and that increasing low-density lipoprotein receptor in astrocytes might represent a novel strategy for treating cerebral ischemic stroke.

Tirofiban mediates neuroprotective effects in acute ischemic stroke by reducing inflammatory response

Growing evidence suggests that neuroinflammation is a critical driver of the development, worsening, and cell death observed in acute ischemic stroke (AIS). While prior research has demonstrated that tirofiban enhances functional recovery in AIS patients by suppressing platelet aggregation, its impact and underlying mechanisms in AIS-related neuroinflammation remain elusive. The current study established an AIS mouse model employing photochemical techniques and assessed neurological function and brain infarct size using the modified neurological severity scale (mNSS) and 2,3,5-Triphenyltetrazolium chloride (TTC) staining, respectively. Tirofiban significantly reduced the volume of cerebral infarction in AIS mice, accompanied by an enhancement in their neurological functions. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays along with experiments assessing oxidative stress showed that tirofiban mitigated oxidative damage and apoptosis in the ischemic penumbra post-AIS. Additionally, DNA microarray analysis revealed alterations in gene expression patterns in the ischemic penumbra after tirofiban treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that most gene-level downregulated signaling pathways were closely related to the inflammatory response. Moreover, the protein microarray analysis revealed that tirofiban diminished the expression levels of inflammatory cytokines, such as interleukin-1 (IL-1), IL-6, and tumor necrosis factor-alpha, in the ischemic penumbra. Additionally, immunofluorescence staining showed that tirofiban regulated inflammatory responses by altering the state and phenotype of microglia. In conclusion, this study suggests that tirofiban reduces inflammatory response by regulating microglial state and phenotype and lowering the levels of inflammatory factors, providing neuroprotection in acute ischemic stroke.

Carbon monoxide-releasing molecule-3 exerts neuroprotection effects after cardiac arrest in mice: A randomized controlled study

Background

Post-cardiac arrest brain injury (PCABI) is the leading cause of death in survivors of cardiac arrest (CA). Carbon monoxide-releasing molecule (CORM-3) is a water-soluble exogenous carbon monoxide that has been shown to have neuroprotection benefits in several neurological disease models. However, the effects of CORM-3 on PCABI is still unclear.

Methods

A mice model combined asystole with hemorrhage was used. Mice were anesthetized and randomized into 4 groups (n = 12/group) and underwent either 9.5 min CA followed by cardiopulmonary resuscitation (CPR) or sham surgery. CORM-3 (30 mg/kg) or vehicle (normal saline) were administered at 1 h after return of spontaneous circulation or sham surgery. Survival, neurologic deficits, alterations in the permeability of the brain-blood barrier and cerebral blood flow, changes of oxidative stress level, level of neuroinflammation and neuronal degeneration, and the activation of Nrf2/HO-1 signaling pathway were measured.

Results

In CORM-3 treated mice that underwent CA/CPR, significantly improved survival (75.00% vs. 58.33%, P = 0.0146 (24 h) and 66.67% vs. 16.67%, P < 0.0001 (72 h)) and neurological function were observed at 24 h and 72 h after ROSC (P < 0.05 for each). Additionally, increased cerebral blood flow, expression of tight junctions, and reduced reactive oxygen species generation at 24 h after ROSC were observed (P < 0.05 for each). CORM-3 treated mice had less neuron death and alleviated neuroinflammation at 72 h after ROSC (P < 0.05 for each). Notably, the Nrf2/HO-1 signaling pathway was significantly activated in mice subjected to CA/CPR with CORM-3 treatment.

Conclusions

CORM-3 could improve survival and exert neuroprotection after CA/CPR in mice. CORM-3 may be a novel and promising pharmacological therapy for PCABI.

Farrerol Alleviates Cerebral Ischemia-Reperfusion Injury by Promoting Neuronal Survival and Reducing Neuroinflammation

Ischemia-reperfusion (I/R) injury is a key influencing factor in the outcome of stroke. Inflammatory response, oxidative stress, and neuronal apoptosis are among the main factors that affect the progression of I/R injury. Farrerol (FAR) is a natural compound that can effectively inhibit the inflammatory response and oxidative stress. However, the role of FAR in cerebral I/R injury remains unknown. In this study, we found that FAR reduced brain injury and neuronal viability after cerebral I/R injury. Meanwhile, administration of FAR also reduced the inflammatory response of microglia after brain injury. Mechanistically, FAR treatment directly reduced neuronal death after oxygen glucose deprivation/re-oxygenation (OGD/R) through enhancing cAMP-response element binding protein (CREB) activation to increase the expression of downstream neurotrophic factors and anti-apoptotic genes. Moreover, FAR decreased the activation of nuclear factor kappa-B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, inhibited microglia activation, and reduced the production of inflammatory cytokines in microglia after OGD/R treatment or LPS stimulation. The compromised inflammatory response by FAR directly promoted the survival of neurons after OGD/R. In conclusion, FAR exerted a protective effect on cerebral I/R injury by directly decreasing neuronal death through upregulating CREB expression and attenuating neuroinflammation. Therefore, FAR could be a potentially effective drug for the treatment of cerebral I/R injury.

AD16 attenuates neuroinflammation induced by cerebral ischemia through down-regulating astrocytes A1 polarization

A1 polarization of astrocytes mediated prolonged inflammation contributing to brain injury in ischemic stroke. We have previously shown that AD16 protects against neonatal hypoxic-ischemic brain damage in vivo and oxygen-glucose deprivation in vitro. More recently, AD16 has demonstrated safety, tolerability, and favorable pharmacokinetics in a randomized controlled phase I trial. In this study, we utilized a rat model of transient middle cerebral artery occlusion (tMCAO) to explore whether the anti-inflammatory compound AD16 protects against ischemic brain injury by regulating A1 polarization and its underlying mechanisms. Our results showed that AD16 treatment significantly reduced the brain infarcted volume and improved neurological function in tMCAO rats. GO analysis results show that differential genes among the Sham, tMCAO and AD16 treatment groups are involved in the regulation of cytokine and inflammatory response. KEGG enrichment pathways analysis mainly enriched in cytokine-cytokine receptor interaction, viral protein interaction with cytokine-cytokine receptor, TNF, chemokine, NF-κB and IL-17 signaling pathway. Furthermore, AD16 treatment decreased the permeability of the blood-brain barrier and suppressed neuroinflammation. AD16 treatment also significantly reduced the polarization of A1 and inhibited NF-κB and JAK2/STAT3 signaling pathways. This study demonstrates that AD16 protects against brain injury in ischemic stroke by reducing A1 polarization to suppress neuroinflammation through downregulating NF-κB and JAK2/STAT3 signaling. Our findings uncover a potential molecular mechanism for AD16 and suggest that AD16 holds promising therapeutic potential against cerebral ischemia.

Sufentanil-induced Nrf2 protein ameliorates cerebral ischemia-reperfusion injury through suppressing neural ferroptosis

As an oxidative stress and inflammation-related disease, cerebral ischemia-reperfusion injury (CIRI) is a prevalent pathogenic factor of ischemic stroke (IS) and seriously degrades the life quality of human beings. As an opioid analgesic for anesthesia, Sufentanil (SUF) can activate the Nrf2 protein-induced anti-oxidant effects, which indicate that SUF may be used as alternative drug for CIRI therapy, but little is known regarding to its molecular mechanisms. Thus, this research aimed to examine whether SUF pre-treatment alleviated CIRI through the modulation of Nrf2 protein-mediated antioxidant activity. Our research revealed that middle cerebral artery occlusion/reperfusion (MCAO/R)-treated rats exhibited apparent CIRI-related symptoms and induced damages in rats' brain, which were all notably mitigated in the MCAO/R rats. The subsequent in vitro cellular experiments verified that oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cytotoxicity were apparently reversed by SUF co-treatment in HT22 and BV2 cells, and it was also validated that SUF was capable of suppressing inflammation and ferroptosis in CIRI models by inhibiting oxidative stress-related damages. Mechanistically, the Akt/GSK-3β pathway was excessively activated by SUF to promote Nrf2 protein expressions and enhance Nrf2-meidated anti-oxidant effects, and it was found that SUF-induced protective effects during CIRI progression were all abrogated by co-treating cells with MK2206 (Akt inhibitor), NP-12 (GSK-3β inhibitor), or ML385 (Nrf2 inhibitor). In conclusion, SUF activated the Akt/GSK-3β pathway to initiate Nrf2 protein-mediated antioxidant effects, which further suppressed oxidative stress-related inflammation and ferroptosis to ameliorate CIRI progression, and SUF could potentially be used as novel therapeutic agent for CIRI treatment in clinic.

Hypoperfusion Intensity Ratio and Hemorrhagic Transformation in Patients with Successful Recanalization after Thrombectomy

BACKGROUND AND PURPOSE

Hemorrhagic transformation remains a potentially devastating complication of acute ischemic stroke. We aimed to evaluate whether the hypoperfusion intensity ratio, a parameter derived from CT perfusion imaging, is associated with the development of hemorrhagic transformation in patients with anterior large-artery occlusion who had undergone thrombectomy.

MATERIALS AND METHODS

We retrospectively reviewed data from patients with consecutive acute ischemic strokes who had achieved successful recanalization (Thrombolysis in Cerebral Infarction score ≥2b) between January 2020 and December 2023. HIR was defined as the ratio of the volume of lesions with a time-to-maximum (Tmax) >6 seconds to those with a Tmax >10 second delay. The primary outcome, based on the European Cooperative Acute Stroke Study, was hemorrhagic transformation, diagnosed by follow-up imaging assessment in 24-hour windows, and radiologically classified as hemorrhagic infarction and parenchymal hematoma. The secondary outcome was a 3-month mRS score of ≥3.

RESULTS

Among 168 patients, 35 of 168 developed hemorrhagic transformation; 14 of 168 developed hemorrhagic infarction, and 21 of 168 developed parenchymal hematoma PH. After adjusting the latent covariates, increased hypoperfusion intensity ratio (per 0.1, adjusted OR [aOR] 1.68, 95% CI 1.26-2.25), ASPECTS (aOR 0.44, 95% CI 0.27-0.72), onset-to-puncture (aOR 1.01, 95% CI 1.00-1.02), and cardioembolism (aOR 5.6, 95% CI 1.59-19.7) were associated with hemorrhagic transformation in multivariable regression. The receiver operating characteristic curve indicated that hypoperfusion intensity ratio can predict hemorrhagic transformation accurately (area under the curve = 0.81; 95% CI, 0.738-0.882; P < .001) and predict parenchymal hematoma (area under the curve = 0.801; 95% CI, 0.727-0.875; P < .001).

CONCLUSIONS

Upon admission, hypoperfusion intensity ratio, an imaging parameter, predicted hemorrhagic transformation after reperfusion therapy in this patient population.

PD-1 mediates microglia polarization via the MAPK signaling pathway to protect blood-brain barrier function during cerebral ischemia/reperfusion

BACKGROUND

Cerebral ischemia is characterized by its rapid onset and high rates of recurrence, morbidity, and mortality, with blood-brain barrier (BBB) permeability playing a vital role in brain injury. Therefore, it is important to understand the molecular mechanism which regulates the BBB during cerebral ischemia.

MATERIALS AND METHODS

An in vitro model of oxygen-glucose deprivation (OGD) and an in vivo model of cerebral ischemia/reperfusion (I/R) were constructed. PD-1 overexpression vectors and vectors containing si-RNA were transfected and injected into in vitro and in vivo models. Western blotting, real-time quantitative PCR (qPCR), immunofluorescence (IF) analysis, and immunohistochemical staining were employed to evaluate the expression levels of programmed cell death-1 (PD-1), microglia M1 and M2 biomarkers, and tight junction proteins. Flow cytometry and ELISA were used to measure the levels of pro-inflammatory cytokines. The BBB permeability of brain tissues was evaluated by Evans blue dye (EBD) extravasation and transendothelial electrical resistance (TEER). Brain water content was measured to assess the extent of inflammatory exudation. The infarct volume and neurological severity score (NSS) were used to assess the severity of brain injury. Brain cell apoptosis was assessed by the TUNEL assay and hematoxylin-eosin (H&E) staining.

RESULTS

PD-1 helped to convert the microglia M1 phenotype to the M2 phenotype and to reduce BBB permeability both in vitro and in vivo. Overexpression of PD-1 promoted a shift of the M1 phenotype to the M2 phenotype and reduced BBB permeability via the ERK and p38 MAPK signaling pathways. PD-1 reduced inflammatory exudation, BBB permeability, cell apoptosis, and brain injury in vivo.

CONCLUSION

Our present study verified that PD-1 exerts an anti-inflammatory effect by converting the microglia M1 phenotype to the M2 phenotype, reducing BBB permeability, and thereby relieves brain injury caused by cerebral ischemia. PD-1 is potential therapeutic target for brain injury caused by cerebral ischemia.

Erianin alleviates cerebral ischemia-reperfusion injury by inhibiting microglial cell polarization and inflammation via the PI3K/AKT and NF-κB pathways

Cerebral ischemia-reperfusion injury (CI/RI) is a leading cause of disability and mortality worldwide, with limited therapeutic options available. Erianin, a natural compound derived from traditional Chinese medicine, has been reported to possess anti-inflammatory and neuroprotective properties. This study aimed to investigate the therapeutic potential of Erianin in CI/RI and elucidate its underlying mechanisms. Network pharmacology analysis predicted that Erianin could target the PI3K/AKT pathway, which are closely associated with CI/RI. In vivo experiments using a rat model of CI/RI demonstrated that Erianin treatment significantly alleviated neurological deficits, reduced infarct volume, and attenuated neuronal damage. Mechanistically, Erianin inhibited microglial cell polarization towards the pro-inflammatory M1 phenotype, as evidenced by the modulation of specific markers. Furthermore, Erianin suppressed the expression of pro-inflammatory cytokines and mediators, such as TNF-α, IL-6, and COX-2, while enhancing the production of anti-inflammatory factors, including Arg1, CD206, IL-4 and IL-10. In vitro studies using oxygen-glucose deprivation/reoxygenation (OGD/R)-stimulated microglial cells corroborated the anti-inflammatory and anti-apoptotic effects of Erianin. Notably, Erianin inhibited the NF-κB signaling pathway by inhibiting p65 phosphorylation and preventing the nuclear translocation of the p65 subunit. Collectively, these findings suggest that Erianin represents a promising therapeutic candidate for CI/RI by targeting microglial cell polarization and inflammation.

Activation of GPR30 Ameliorates Cerebral Ischemia-Reperfusion Injury by Suppressing Ferroptosis Through Nrf2/GPX4 Signaling Pathway

The newly identified estrogen receptor, G protein-coupled receptor 30 (GPR30), is prevalent in the brain and has been shown to provide significant neuroprotection. Recent studies have linked ferroptosis, a newly characterized form of programmed cell death, closely with cerebral ischemia-reperfusion injury (CIRI), highlighting it as a major contributing factor. Consequently, our research aimed to explore the potential of GPR30 targeting in controlling neuronal ferroptosis and lessening CIRI impacts. Results indicated that GPR30 activation not only improved neurological outcomes and decreased infarct size in a mouse model but also lessened iron accumulation and malondialdehyde formation post-middle cerebral artery occlusion (MCAO). This protective effect extended to increased levels of Nrf2 and GPX4 proteins. Similar protective results were replicated in PC12 cells subjected to Oxygen Glucose Deprivation and Reoxygenation (OGD/R) using the GPR30-specific agonist G1. Importantly, inhibition of Nrf2 with ML385 curtailed the neuroprotective effects of GPR30 activation, suggesting that GPR30 mitigates CIRI primarily through inhibition of neuronal ferroptosis via upregulation of Nrf2 and GPX4.

Effect of dexmedetomidine on ncRNA and mRNA profiles of cerebral ischemia-reperfusion injury in transient middle cerebral artery occlusion rats model

Ischemic stroke poses a significant global health burden, with rapid revascularization treatments being crucial but often insufficient to mitigate ischemia-reperfusion (I/R) injury. Dexmedetomidine (DEX) has shown promise in reducing cerebral I/R injury, but its potential molecular mechanism, particularly its interaction with non-coding RNAs (ncRNAs), remains unclear. This study investigates DEX's therapeutic effect and potential molecular mechanisms in reducing cerebral I/R injury. A transient middle cerebral artery obstruction (tMACO) model was established to simulate cerebral I/R injury in adult rats. DEX was administered pre-ischemia and post-reperfusion. RNA sequencing and bioinformatic analyses were performed on the ischemic cerebral cortex to identify differentially expressed non-coding RNAs (ncRNAs) and mRNAs. The sequencing results showed 6,494 differentially expressed (DE) mRNA and 2698 DE circRNA between the sham and tMCAO (I/R) groups. Additionally, 1809 DE lncRNA, 763 DE mRNA, and 2795 DE circRNA were identified between the I/R group and tMCAO + DEX (I/R + DEX) groups. Gene ontology (GO) analysis indicated significant enrichment in multicellular biogenesis, plasma membrane components, and protein binding. KEGG analysis further highlighted the potential mechanism of DEX action in reducing cerebral I/R injury, with hub genes involved in inflammatory pathways. This study demonstrates DEX's efficacy in reducing cerebral I/R injury and offers insights into its brain-protective effects, especially in ischemic stroke. Further research is warranted to fully understand DEX's neuroprotective mechanisms and its clinical applications.

Vascular Aging in Ischemic Stroke

Cellular senescence, a permanent halt in cell division due to stress, spurs functional and structural changes, contributing to vascular aging characterized by endothelial dysfunction and vascular remodeling. This process raises the risk of ischemic stroke (IS) in older individuals, with its mechanisms still not completely understood despite ongoing research efforts. In this review, we have analyzed the impact of vascular aging on increasing susceptibility and exacerbating the pathology of IS. We have emphasized the detrimental effects of endothelial dysfunction and vascular remodeling influenced by oxidative stress and inflammatory response on vascular aging and IS. Our goal is to aid the understanding of vascular aging and IS pathogenesis, particularly benefiting older adults with high risk of IS.

Therapeutic potential of fucoidan in central nervous system disorders: A systematic review

Central nervous system (CNS) disorders have a complicated pathogenesis, and to date, no single mechanism can fully explain them. Most drugs used for CNS disorders primarily aim to manage symptoms and delay disease progression, and none have demonstrated any pathological reversal. Fucoidan is a safe, sulfated polysaccharide from seaweed that exhibits multiple pharmacological effects, and it is anticipated to be a novel treatment for CNS disorders. To assess the possible clinical uses of fucoidan, this review aims to provide an overview of its neuroprotective mechanism in both in vivo and in vitro CNS disease models, as well as its pharmacokinetics and safety. We included 39 articles on the pharmacology of fucoidan in CNS disorders. In vitro and in vivo experiments demonstrate that fucoidan has important roles in regulating lipid metabolism, enhancing the cholinergic system, maintaining the functional integrity of the blood-brain barrier and mitochondria, inhibiting inflammation, and attenuating oxidative stress and apoptosis, highlighting its potential for CNS disease treatment. Fucoidan has a protective effect against CNS disorders. With ongoing research on fucoidan, it is expected that a natural, highly effective, less toxic, and highly potent fucoidan-based drug or nutritional supplement targeting CNS diseases will be developed.

The cerebroprotection and prospects of FNDC5/irisin in stroke

Stroke, the leading cause of disability and cognitive impairment, is also the second leading cause of death worldwide. The drugs with multi-targeted brain cytoprotective effects are increasingly being advocated for the treatment of stroke. Irisin, a newly discovered myokine produced by cleavage of fibronectin type III domain 5, has been shown to regulate glucose metabolism, mitochondrial energy, and fat browning. A large amount of evidence indicated that irisin could exert anti-inflammatory, anti-apoptotic, and antioxidant properties in a variety of diseases such as myocardial infarction, inflammatory bowel disease, lung injury, and kidney or liver disease. Studies have found that irisin is widely distributed in multiple brain regions and also plays an important regulatory role in the central nervous system. The most common cause of a stroke is a sudden blockage of an artery (ischemic stroke), and in some circumstances, a blood vessel rupture can also result in a stroke (hemorrhagic stroke). After a stroke, complicated pathophysiological processes lead to serious brain injury and neurological dysfunction. According to recent investigations, irisin may protect elements of the neurovascular unit by acting on multiple pathological processes in stroke. This review aims to outline the currently recognized effects of irisin on stroke and propose possible directions for future research.

TET1 mediated m5C modification of RelB aggravates cerebral ischemia/reperfusion-induced neuroinflammation through regulating microglia polarization

Microglia mediated neuroinflammation is one of the major contributors to brain damage in cerebral ischemia reperfusion injury (CI/RI). Recently, RNA modification was found to contribute to the regulation of microglia polarization and the subsequent development of cerebral I/R neuroinflammation. Herein, we investigated the effect and mechanism of m5C RNA modification in the microglia induced CI/RI neuroinflammation. We found that the m5C RNA modification levels decreased in the primary microglia isolated from a mouse model of intraluminal middle cerebral artery occlusion/reperfusion (MCAO/R) and the BV2 microglial cells subjected to oxygen-glucose deprivation and reoxygenation (OGD/R), and this change was accompanied by an increase in the M1/M2 polarization ratio. Furthermore, the expression of m5C demethylase TET1 in microglia increased, which promoted M1 polarization but impeded M2 polarization. Mechanistically, the higher TET1 expression decreased the m5C modification level of RelB and enhanced its mRNA stability, which subsequently increased the M1/M2 polarization ratio. In conclusion, this study provides insight into the role of m5C RNA modification in the pathogenesis of cerebral I/R neuroinflammation and may deepen our understanding on clinical therapy targeting the TET1-RelB axis.

Stem cell grafts enhance endogenous extracellular vesicle expression in the stroke brain

Endogenous brain repair occurs following an ischemic stroke but is transient, thus unable to fully mount a neuroprotective response against the evolving secondary cell death. Finding a treatment strategy that may render robust and long-lasting therapeutic effects stands as a clinically relevant therapy for stroke. Extracellular vesicles appear to be upregulated after stroke, which may represent a candidate target for neuroprotection. In this study, we probed whether transplanted stem cells could enhance the expression of extracellular vesicles to afford stable tissue remodeling in the ischemic stroke brain. Aged rats were initially exposed to the established ischemic stroke model of middle cerebral artery occlusion then received intravenous delivery of either bone marrow-derived mesenchymal stem cell transplantation or vehicle. A year later, the animals were assayed for brain damage, inflammation, and extracellular vesicle expression. Our findings revealed that while core infarction was not reduced, the stroke animals transplanted with stem cells displayed a significant reduction in peri-infarct cell loss that coincided with downregulated Iba1-labeled inflammatory cells and upregulated CD63-positive extracellular vesicles that appeared to be co-localized with GFAP-positive astrocytes. Interestingly, grafted stem cells were not detected at one year post-transplantation period, suggesting that the extracellular vesicles likely originated within the host brain. That long-lasting functional benefits persisted in the absence of surviving transplanted stem cells, but with upregulation of endogenous extracellular vesicles, advances the concept that transplantation of stem cells acutely after stroke propels host extracellular vesicles to the ischemic brain, altogether promoting chronic brain remodeling.

Deciphering Mechanisms, Prevention Strategies, Management Plans, Medications, and Research Techniques for Strokes in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune rheumatic condition characterized by an unpredictable course and a wide spectrum of manifestations varying in severity. Individuals with SLE are at an increased risk of cerebrovascular events, particularly strokes. These strokes manifest with a diverse range of symptoms that cannot be solely attributed to conventional risk factors, underscoring their significance among the atypical risk factors in the context of SLE. This complexity complicates the identification of optimal management plans and the selection of medication combinations for individual patients. This susceptibility is further complicated by the nuances of neuropsychiatric SLE, which reveals a diverse array of neurological symptoms, particularly those associated with ischemic and hemorrhagic strokes. Given the broad range of clinical presentations and associated risks linking strokes to SLE, ongoing research and comprehensive care strategies are essential. These efforts are critical for improving patient outcomes by optimizing management strategies and discovering new medications. This review aims to elucidate the pathological connection between SLE and strokes by examining neurological manifestations, risk factors, mechanisms, prediction and prevention strategies, management plans, and available research tools and animal models. It seeks to explore this medical correlation and discover new medication options that can be tailored to individual SLE patients at risk of stroke.

Protective Effects of Adropin in Experimental Subarachnoid Hemorrhage

PURPOSE

We aimed to investigate early effects of exogenously administered adropin (AD) on neurological function, endothelial nitric oxide synthase (eNOS) expression, nitrite/nitrate levels, oxidative stress, and apoptosis in subarachnoid hemorrhage (SAH).

METHODS

Following intracerebroventricular AD administration (10 µg/5 µl at a rate of 1 µl/min) SAH model was carried out in Sprague-Dawley rats by injection of autologous blood into the prechiasmatic cistern. The effects of AD were assessed 24 h following SAH. The modified Garcia score was employed to evaluate functional insufficiencies. Adropin and caspase-3 proteins were measured by ELISA, while nitrite/nitrate levels, total antioxidant capacity (TAC) and reactive oxygen/nitrogen species (ROS/RNS) were assayed by standard kits. eNOS expression and apoptotic neurons were detected by immunohistochemical analysis.

RESULTS

The SAH group performed notably lower on the modified Garcia score compared to sham and SAH + AD groups. Adropin administration increased brain eNOS expression, nitrite/nitrate and AD levels compared to SHAM and SAH groups. SAH produced enhanced ROS/RNS generation and reduced antioxidant capacity in the brain. Adropin boosted brain TAC and diminished ROS/RNS production in SAH rats and no considerable change amongst SHAM and SAH + AD groups were detected. Apoptotic cells were notably increased in intensity and number after SAH and were reduced by AD administration.

CONCLUSIONS

Adropin increases eNOS expression and reduces neurobehavioral deficits, oxidative stress, and apoptotic cell death in SAH model. Presented results indicate that AD provides protection in early brain injury associated with SAH.

Advancing stroke therapy: innovative approaches with stem cell-derived extracellular vesicles

Stroke is a leading cause of mortality and long-term disability globally, with acute ischemic stroke (AIS) being the most common subtype. Despite significant advances in reperfusion therapies, their limited time window and associated risks underscore the necessity for novel treatment strategies. Stem cell-derived extracellular vesicles (EVs) have emerged as a promising therapeutic approach due to their ability to modulate the post-stroke microenvironment and facilitate neuroprotection and neurorestoration. This review synthesizes current research on the therapeutic potential of stem cell-derived EVs in AIS, focusing on their origin, biogenesis, mechanisms of action, and strategies for enhancing their targeting capacity and therapeutic efficacy. Additionally, we explore innovative combination therapies and discuss both the challenges and prospects of EV-based treatments. Our findings reveal that stem cell-derived EVs exhibit diverse therapeutic effects in AIS, such as promoting neuronal survival, diminishing neuroinflammation, protecting the blood-brain barrier, and enhancing angiogenesis and neurogenesis. Various strategies, including targeting modifications and cargo modifications, have been developed to improve the efficacy of EVs. Combining EVs with other treatments, such as reperfusion therapy, stem cell transplantation, nanomedicine, and gut microbiome modulation, holds great promise for improving stroke outcomes. However, challenges such as the heterogeneity of EVs and the need for standardized protocols for EV production and quality control remain to be addressed. Stem cell-derived EVs represent a novel therapeutic avenue for AIS, offering the potential to address the limitations of current treatments. Further research is needed to optimize EV-based therapies and translate their benefits to clinical practice, with an emphasis on ensuring safety, overcoming regulatory hurdles, and enhancing the specificity and efficacy of EV delivery to target tissues.

Effects of perioperative hydrogen inhalation on brain edema and prognosis in patients with glioma: a single-center, randomized controlled study

Introduction

Brain edema is a life-threatening complication that occurs after glioma surgery. There are no noninvasive and specific treatment methods for brain edema. Hydrogen is an anti-inflammatory and antioxidant gas that has demonstrated therapeutic and preventative effects on several diseases, particularly in the nervous system. This study aimed to determine the therapeutic effects of hydrogen administration on brain edema following glioma surgery and elucidate its mechanism.

Methods

A single-center, randomized controlled clinical trial of hydrogen inhalation was conducted (China Clinical Trial Registry [ChiCTR-2300074362]). Participants in hydrogen (H) group that inhaled hydrogen experienced quicker alleviation of postoperative brain edema compared with participants in control (C) group that inhaled oxygen.

Results

The volume of brain edema before discharge was significantly lower in the H group (p < 0.05). Additionally, the regression rate of brain edema was higher in the H group than in the C group, which was statistically significant (p < 0.05). Furthermore, 3 days after surgery, the H group had longer total sleep duration, improved sleep efficiency, shorter sleep latency, and lower numerical rating scale (NRS) scores (p < 0.05).

Discussion

In conclusion, hydrogen/oxygen inhalation effectively reduced postoperative brain edema in glioma patients. Further research is necessary to understand the underlying mechanisms of hydrogen's therapeutic effects. Hydrogen is expected to become a new target for future adjuvant therapy for brain edema.

Constructing a Transient Ischemia Attack Model Utilizing Flexible Spatial Targeting Photothrombosis with Real-Time Blood Flow Imaging Feedback

Transient ischemic attack (TIA) is an early warning sign of stroke and death, necessitating suitable animal models due to the associated clinical diagnostic challenges. In this study, we developed a TIA model using flexible spatially targeted photothrombosis combined with real-time blood flow imaging feedback. By modulating the excitation light using wavefront technology, we precisely created a square light spot (50 × 250 µm), targeted at the distal middle cerebral artery (dMCA). The use of laser speckle contrast imaging (LSCI) provided real-time feedback on the ischemia, while the excitation light was ceased upon reaching complete occlusion. Our results demonstrated that the photothrombus formed in the dMCA and spontaneously recanalized within 10 min (416.8 ± 96.4 s), with no sensorimotor deficits or infarction 24 h post-TIA. During the acute phase, ischemic spreading depression occurred in the ipsilateral dorsal cortex, leading to more severe ischemia and collateral circulation establishment synchronized with the onset of dMCA narrowing. Post-reperfusion, the thrombi were primarily in the sensorimotor and visual cortex, disappearing within 24 h. The blood flow changes in the dMCA were more indicative of cortical ischemic conditions than diameter changes. Our method successfully establishes a photochemical TIA model based on the dMCA, allowing for the dynamic observation and control of thrombus formation and recanalization and enabling real-time monitoring of the impacts on cerebral blood flow during the acute phase of TIA.

Detecting viscosity changes in the limb ischemia-reperfusion in mice with a near-infrared fluorescence probe

BACKGROUND

Limb ischemia-reperfusion is a common phenomenon in clinical surgery, which disrupts the balanced physiological response process and ultimately leads to changes in intracellular viscosity. Intracellular viscosity is an important microenvironmental parameter that affects the normal function of organisms, and its level is closely related to many diseases. In addition, oxidative stress in the lower limbs can impair body function, and changes in pressure can lead to changes in the viscosity of limb tissues. Therefore, it is necessary to develop effective tools to detect changes in intracellular viscosity and visualize the progression of hind limb ischemia-reperfusion injury.

RESULTS

In order to solve this problem, a near infrared viscometry sensitive fluorescence probe (PH-XQ) with long emission wavelength and stable luminescence performance was designed and synthesized by using oxanthracene derivatives and malononitrile. The fluorescence probe (PH-XQ) has excellent selectivity, high sensitivity, low toxicity, high biocompatibility and excellent detection performance. The fluorescence intensity of the PH-XQ probe at 667 nm is highly sensitive to the change of viscosity. With the increase of viscosity, the fluorescence intensity of probe PH-XQ was significantly enhanced, and the fluorescence enhancement ratio was about 14-fold. In addition, PH-XQ can detect not only changes in viscosity between normal cells and drug-induced inflammatory cells, but also changes in the viscosity of the hind limbs of normal mice and mice after ischemia reperfusion.

SIGNIFICANCE

In particular, we are the first to successfully detect changes in handlimb viscosity after ischemia-reperfusion in mice using a probe. This study clearly elucidates changes in viscosity during ischemia-reperfusion of mouse limbs, providing favorable support for the relationship between viscosity and related diseases, and further providing a potential tool for the diagnosis of viscosity-related diseases.

Disulfiram downregulates ferredoxin 1 to maintain copper homeostasis and inhibit inflammation in cerebral ischemia/reperfusion injury

In the current study, we aimed to investigate whether disulfiram (DSF) exerts a neuroprotective role in cerebral ischemiareperfusion (CI-RI) injury by modulating ferredoxin 1 (FDX1) to regulate copper ion (Cu) levels and inhibiting inflammatory responses. To simulate CI-RI, a transient middle cerebral artery occlusion (tMCAO) model in C57/BL6 mice was employed. Mice were administered with or without DSF before and after tMCAO. Changes in infarct volume after tMCAO were observed using TTC staining. Nissl staining and hematoxylin-eosin (he) staining were used to observe the morphological changes of nerve cells at the microscopic level. The inhibitory effect of DSF on initial inflammation was verified by TUNEL assay, apoptosis-related protein detection and iron concentration detection. FDX1 is the main regulatory protein of copper death, and the occurrence of copper death will lead to the increase of HSP70 stress and inflammatory response. Cuproptosis-related proteins and downstream inflammatory factors were detected by western blotting, immunofluorescence staining, and immunohistochemistry. The content of copper ions was detected using a specific kit, while electron microscopy was employed to examine mitochondrial changes. We found that DSF reduced the cerebral infarction volume, regulated the expression of cuproptosis-related proteins, and modulated copper content through down regulation of FDX1 expression. Moreover, DSF inhibited the HSP70/TLR-4/NLRP3 signaling pathway. Collectively, DSF could regulate Cu homeostasis by inhibiting FDX1, acting on the HSP70/TLR4/NLRP3 pathway to alleviate CI/RI. Accordingly, DSF could mitigate inflammatory responses and safeguard mitochondrial integrity, yielding novel therapeutic targets and mechanisms for the clinical management of ischemia-reperfusion injury.

Bibliometric analysis of research progress on tetramethylpyrazine and its effects on ischemia-reperfusion injury

In recent decades, natural products have attracted worldwide attention and become one of the most important resources for pharmacological industries and medical sciences to identify novel drug candidates for disease treatment. Tetramethylpyrazine (TMP) is an alkaloid extracted from Ligusticum chuanxiong Hort., which has shown great therapeutic potential in cardiovascular and cerebrovascular diseases, liver and renal injury, as well as cancer. In this review, we analyzed 1270 papers published on the Web of Science Core Collection from 2002 to 2022 and found that TMP exerted significant protective effects on ischemia-reperfusion (I/R) injury that is the cause of pathological damages in a variety of conditions, such as ischemic stroke, myocardial infarction, acute kidney injury, and liver transplantation. TMP is limited in clinical applications to some extent due to its rapid metabolism, a short biological half-life and poor bioavailability. Obviously, the structural modification, administration methods and dosage forms of TMP need to be further investigated in order to improve its bioavailability. This review summarizes the clinical applications of TMP, elucidates its potential mechanisms in protecting I/R injury, provides strategies to improve bioavailability, which presents a comprehensive understanding of the important compound. Hopefully, the information and knowledge from this review can help researchers and physicians to better improve the applications of TMP in the clinic.

JR14a: A novel antagonist of C3aR attenuates neuroinflammation in cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury (CIRI), a prevalent stroke-related complication, can lead to severe brain damage. Inflammation is a crucial factor in CIRI pathogenesis, and the complement component 3a receptor (C3aR) could be a key mediator in the post-CIRI inflammatory cascade. In this study, the role of C3aR in CIRI was investigated utilizing a middle cerebral artery occlusion (MCAO) model in C3aR knockout (KO) mice. Magnetic resonance imaging (MRI) and neurofunctional assessments revealed that C3aR KO mice exhibited significantly diminished cerebral infarction and improved neurological impairments. Consequently, the focus shifted to searching for a small molecule antagonist of C3aR. JR14a, a new potent thiophene antagonist of C3aR, was injected intraperitoneally into mice 1-h post-MCAO model implementation. The mass spectrometry (MS) results indicated the ability of JR14a to penetrate the blood-brain barrier. Subsequent TTC staining and neurofunctional assessments revealed the efficacy of JR14a in reducing cerebral infarct volume and neurological impairment following MCAO. In addition, immunofluorescence (IF) and immunohistochemistry (IHC) demonstrated attenuated microglial activation, neutrophil infiltration, and blood-brain barrier disruption by JR14a in the MCAO model. Furthermore, enzyme-linked immunosorbent assay (ELISA) and Western blotting supported the role of JR14a in downregulating the expression levels of C3aR, tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6), as well as the phosphorylation of p65. In conclusion, the findings suggested that C3aR could be a potential therapeutic target for CIRI, and JR14a emerged as a promising treatment candidate.

Neuroprotective effect of autologous mitochondrial transplantation against global ischemia/reperfusion injury in a rat model of cardiac arrest

BACKGROUND

Mitochondria have emerged as a promising target for ischemic disease. A previous study reported the application of mitochondrial transplantation in focal cerebral ischemia/reperfusion injury, but it is unclear whether exogenous mitochondrial transplantation could be a therapeutic strategy for global ischemia/reperfusion injury induced by cardiac arrest.

METHODS

We hypothesized that transplantation of autologous mitochondria would rescue hippocampal cells and alleviate neurological impairment after cardiac arrest. In this study, we employed a rat cardiac arrest-global cerebral ischemia injury model (CA-GCII) and transplanted isolated mitochondria intravenously. Behavior test was applied to assess neurological deficit. Apoptosis and mitochondria permeability transition pore opening in hippocampus was determined using immunoblotting and swelling assay, respectively.

RESULTS

Transplanted mitochondria distributed throughout hippocampal cells and reduced oxidative stress. An improved neurological outcome was observed in rats receiving autologous mitochondria. In the hippocampus, mitophagy was enhanced while cell apoptosis was induced by ischemia/reperfusion insult was downregulated by mitochondrial transplantation. Mitochondrial permeability transition pore (MPTP) opening in surviving hippocampal cells was also suppressed.

CONCLUSIONS

These results indicated that transplantation of autologous mitochondria rescued hippocampal cells from ischemia/reperfusion injury and ameliorated neurological impairment caused by cardiac arrest.

MyD88 Inhibition Attenuates Cerebral Ischemia-reperfusion Injury by Regulating the Inflammatory Response and Reducing Blood-brain Barrier Damage

Myeloid differentiation primary response gene 88 (MyD88), a downstream molecule directly linked to Toll-like receptor (TLRs) and IL1 receptor, has been implicated in ischemia-reperfusion injury across various organs. However, its role in cerebral ischemia-reperfusion injury (CIRI) remains unclear. Five transient middle cerebral artery occlusion (tMCAO) microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. We screened these datasets for differentially expressed genes (DEGs) using the GSE35338 and GSE58720 datasets and performed weighted gene co-expression network analysis (WGCNA) using the GSE30655, GSE28731, and GSE32529 datasets to identify the core module related to tMCAO. A protein-protein interaction (PPI) network was constructed using the intersecting DEGs and genes in the core module. Finally, we identified Myd88 was the core gene. In addition, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) validated that TNFα, IL17, and MyD88 signaling pathways were significantly enriched in tMCAO. Subsequently, we investigated the mechanistic role of MyD88 in the tMCAO model using male C57BL/6 mice. MyD88 expression increased significantly 24 h after reperfusion. After intraperitoneal administration of TJ-M2010-5, a MyD88-specific inhibitor, during reperfusion, the infarction volumes in the mice were ameliorated. TJ-M2010-5 inhibits the activation of microglia and astrocytes. Moreover, it attenuates the upregulation of inflammatory cytokines TNFα, IL17, and MMP9 while preserving the expression level of ZO1 after tMCAO, thereby safeguarding against blood-brain barrier (BBB) disruption. Finally, our findings suggest that MyD88 regulates the IRAK4/IRF5 signaling pathway associated with microglial activation. MyD88 participates in CIRI by regulating the inflammatory response and BBB damage following tMCAO.

Targeted Delivery of Macrophage Membrane Biomimetic Liposomes Through Intranasal Administration for Treatment of Ischemic Stroke

Purpose

Ginsenoside Rg3 (Rg3) and Panax notoginseng saponins (PNS) can be used for ischemic stroke treatment, however, the lack of targeting to the ischemic region limits the therapeutic effect. To address this, we leveraged the affinity of macrophage membrane proteins for inflamed brain microvascular endothelial cells to develop a macrophage membrane-cloaked liposome loaded with Rg3 and PNS (MM-Lip-Rg3/PNS), which can precisely target brain lesion region through intranasal administration.

Methods

MM-Lip-Rg3/PNS was prepared by co-extrusion method and was performed by characterization, stability, surface protein, and morphology. The cellular uptake, immune escape ability, and blood-brain barrier crossing ability of MM-Lip-Rg3/PNS were studied in vitro. The in vivo brain targeting, biodistribution and anti-ischemic efficacy of MM-Lip-Rg3/PNS were evaluated in MACO rats, and we determined the diversity of the nasal brain pathway through the olfactory nerve blockade model in rats. Finally, the pharmacokinetics and brain targeting index of MM-Lip-Rg3/PNS were investigated.

Results

Our results indicated that MM-Lip-Rg3/PNS was spherical with a shell-core structure. MM-Lip-Rg3/PNS can avoid mononuclear phagocytosis, actively bind to inflammatory endothelial cells, and have the ability to cross the blood-brain barrier. Moreover, MM-Lip-Rg3/PNS could specifically target ischemic sites, even microglia, increase the cumulative number of drugs in the brain, improve the inflammatory environment of the brain, and reduce the infarct size. By comparing olfactory nerve-blocking rats with normal rats, it was found that there are direct and indirect pathways for nasal entry into the brain. Pharmacokinetics demonstrated that MM-Lip-Rg3/PNS exhibited stronger brain targeting and prolonged drug half-life.

Conclusion

MM-Lip-Rg3/PNS might contribute to the accumulation of Rg3 and PNS in the ischemic brain area to improve treatment efficacy. This biomimetic nano-drug delivery system provides a new and promising strategy for the treatment of ischemic stroke.

Neutrophil Targeting Platform Reduces Neutrophil Extracellular Traps for Improved Traumatic Brain Injury and Stroke Theranostics

Traumatic brain injuries (TBI) and stroke are major causes of morbidity and mortality in both developing and developed countries. The complex and heterogeneous pathophysiology of TBI and cerebral ischemia-reperfusion injury (CIRI), in addition to the blood-brain barrier (BBB) resistance, is a major barrier to the advancement of diagnostics and therapeutics. Clinical data showed that the severity of TBI and stroke is positively correlated with the number of neutrophils in peripheral blood and brain injury sites. Furthermore, neutrophil extracellular traps (NETs) released by neutrophils correlate with worse TBI and stroke outcomes by impairing revascularization and vascular remodeling. Therefore, targeting neutrophils to deliver NETs inhibitors to brain injury sites and reduce the formation of NETs can be an optimal strategy for TBI and stroke therapy. Herein, the study designs and synthesizes a reactive oxygen species (ROS)-responsive neutrophil-targeting delivery system loaded with peptidyl arginine deiminase 4 (PAD4) inhibitor, GSK484, to prevent the formation of NETs in brain injury sites, which significantly inhibited neuroinflammation and improved neurological deficits, and improved the survival rate of TBI and CIRI. This strategy may provide a groundwork for the development of targeted theranostics of TBI and stroke.

The alpha2-adrenergic receptor agonist clonidine protects against cerebral ischemia/reperfusion induced neuronal apoptosis in rats

Apoptosis is the crucial pathological mechanism following cerebral ischemic injury. Our previous studies demonstrated that clonidine, one agonist of alpha2-adrenergic receptor (α2-AR), could attenuate cerebral ischemic injury in a rat model of middle cerebral artery occlusion/reperfusion (MCAO/R). However, it's unclear whether clonidine exerts neuroprotective effects by regulating neuronal apoptosis. In this study, we elucidated whether clonidine can exert anti-apoptotic effects in cerebral ischemic injury, and further explored the possible mechanisms. Neurological deficit score was measured to evaluate the neurological function. TTC staining was used for the measurement of brain infarct size. Hematoxylin-Eosin (HE) staining was applied to examine the cell morphology. TUNEL and DAPI fluorescent staining methods were used to analyze the cell apoptosis in brain tissue. Fluorescence quantitative real-time PCR was performed to assess the gene expression of Caspase-3 and P53. Western blotting assay was applied to detect the protein expression of Caspase-3 and P53. The results showed that clonidine improved neurological function, reduced brain infarct size, alleviated neuronal damage, and reduced the ratio of cell apoptosis in the brain with MCAO/R injury. moreover, clonidine down-regulated the gene and protein expression of Caspase-3 and P53 which were over-expressed after MCAO/R injury. Whereas, yohimbine (one selective α2-AR antagonist) mitigated the anti-apoptosis effects of clonidine, accompanied by reversed gene and protein expression changes. The results indicated that clonidine attenuated cerebral MCAO/R injury via suppressing neuronal apoptosis, which may be mediated, at least in part, by activating α2-AR.

Systemic biomarker associated with poor outcome after futile reperfusion

BACKGROUND

Successful recanalization does not lead to complete tissue reperfusion in a considerable percentage of ischemic stroke patients. This study aimed to identify biomarkers associated with futile recanalization. Leukoaraiosis predicts poor outcomes of this phenomenon. Soluble tumour necrosis factor-like weak inducer of apoptosis (sTWEAK), which is associated with leukoaraiosis degrees, could be a potential biomarker.

METHODS

This study includes two cohorts of ischemic stroke patients in a multicentre retrospective observational study. Effective reperfusion, defined as a reduction of ≥8 points in the National Institutes of Health Stroke Scale (NIHSS) within the first 24 h, was used as a clinical marker of effective reperfusion.

RESULTS

In the first cohort study, female sex, age, and high NIHSS at admission (44.7% vs. 81.1%, 71.3 ± 13.7 vs. 81.1 ± 6.7; 16 [13, 21] vs. 23 [17, 28] respectively; p < .0001) were confirmed as predictors of futile recanalization. ROC curve analysis showed that leukocyte levels (sensitivity of 99%, specificity of 55%) and sTWEAK level (sensitivity of 92%, specificity of 88%) can discriminate between poor and good outcomes. Both biomarkers simultaneously are higher associated with outcome after effective reperfusion (OR: 2.17; CI 95% 1.63-4.19; p < .0001) than individually (leukocytes OR: 1.38; CI 95% 1.00-1.64, p = .042; sTWEAK OR: 1.00; C I95% 1.00-1.01, p = .019). These results were validated using a second cohort, where leukocytes and sTWEAK showed a sensitivity of 100% and specificity of 66.7% and 75% respectively.

CONCLUSIONS

Leukocyte and sTWEAK could be biomarkers of reperfusion failure and subsequent poor outcomes. Further studies will be necessary to explore its role in reperfusion processes.

Aquaporins alteration revealed kidney damages in cerebral ischemia/reperfusion rats

Background

Restoration of blood supply is a desired goal for the treatment of acute ischemic stroke. However, the restoration often leads to cerebral ischemia-reperfusion injury (CIR/I), which greatly increases the risk of non-neural organ damage. In particular, the acute kidney injury might be one of the most common complications.

Aims

The study aimed to understand the damage occurred and the potential molecular mechanisms.

Methods

The study was explored on the CIR/I rats generated by performing middle cerebral artery occlusion/reperfusion (MCAO/Reperfusion). The rats were evaluated with injury on the brains, followed by the non-neural organs including kidneys, livers, colons and stomachs. They were examined further with histopathological changes, and gene expression alterations by using RT-qPCR of ten aquaporins (Aqps) subtypes including Aqp1～Aqp9 and Aqp11. Furthermore, the Aqps expression profiles were constructed for each organ and analyzed by performing Principle Component Analysis. In addition, immunohistochemistry was explored to look at the protein expression of Aqp1, Aqp2, Aqp3 and Aqp4 in the rat kidneys.

Results

There was a prominent down-regulation profile in the MCAO/Reperfusion rat kidneys. The protein expression of Aqp1, Aqp2, Aqp3 and Aqp4 was decreased in the kidneys of the MCAO/Reperfusion rats. We suggested that the kidney was in the highest risk to be damaged following the CIR/I. Down-regulation of Aqp2, Aqp3 and Aqp4 was involved in the acute kidney injury induced by the CIR/I.

Maresin1 alleviates neuroinflammation by inhibiting caspase-3/ GSDME-mediated pyroptosis in mice cerebral ischemia-reperfusion model

OBJECTIVE

To explore the mechanism of Maresin1 in reducing cerebral ischemia-reperfusion injury.

MATERIALS AND METHODS

Male C57BL/6 mice were randomly divided (n = 5 in each group), and focal middle cerebral artery occlusion (MCAO) model was used to simulate cerebral ischemia/reperfusion injury. TTC and the Longa score were used to detect the degree of neurological deficits. Western blot was used to detect the expression levels of GSDME, GSDME-N, caspase-3 and cleaved caspase-3 in cerebral ischemic penumbra tissue, and immunofluorescence was used to detect the expression levels of GSDME-N. The mRNA expression levels of GSDME and pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) were detected by RT-PCR.

RESULTS

Compared with sham group, GSDME mRNA levels in MCAO group were significantly increased at 12 h and 24 h after reperfusion, and GSDME and GSDME-N significantly increased at 6-48 h after reperfusion. Compared with sham group, the percentage of infarct size, the Longa score, the mRNA expression levels of IL-1β, IL-6 and TNF-α, and GSDME, GSDME-N, caspase-3 and cleaved caspase-3 in MCAO group was significantly increased. Then, the percentage of infarct size and the Longa score significantly decreased after MaR1 administration, the mRNA expression levels of IL-1β and IL-6 downregulated, and GSDME, GSDME-N, caspase-3 and cleaved caspase-3 were also reduced. After administration of Z-DEVD-FMK(ZDF), the expression of caspase-3, cleaved caspase-3 and GSDME-N was decreased, which in MCAO+MaR1+ZDF group was not statistically significant compared with MCAO+ ZDF group.

CONCLUSION

Maresin1 alleviates cerebral ischemia/reperfusion injury by inhibiting pyroptosis mediated by caspase-3/GSDME pathway and alleviating neuroinflammation.

Sophoricoside ameliorates cerebral ischemia-reperfusion injury dependent on activating AMPK

AIMS

Ischemic stroke accounts for 87% of all strokes, and its death and disability bring a huge burden to society. Brain injury caused by ischemia-reperfusion (I/R) is also a major difficulty in clinical treatment and prognosis. Sophoricoside (SOP) is an isoflavone glycoside isolated from the seed of medical herb Sophora japonica L. Previously, SOP was found to be effective in anti-inflammation and glucose-lipid metabolism-related diseases. In order to investigate whether SOP has a regulatory effect on cerebral I/R injury, we conducted this study.

METHODS

Here, by application of SOP into MCAO (transient middle cerebral artery occlusion)-induced mice and OGD/R (oxygen glucose deprivation/reperfusion)-induced primary neurons, the regulation effects of SOP was analyzed by detecting neurological score of post-stroke mice, phenotypes of brains and brain sections, cell viabilities, and apoptosis- and inflammation-regulation. RNA sequencing and molecular biology experiments were performed to explore the mechanism of SOP regulating cerebral I/R injury.

RESULTS

SOP administration decreased the infarct size, neurological deficit score, neuronal cell injury, inflammation and apoptosis. Mechanistically, SOP exerted its protective effect by activating the AMP-activated protein kinase (AMPK) signaling pathway.

CONCLUSION

SOP inhibits cerebral I/R injury by promoting the phosphorylation of AMPK.

HMGB1: A New Target for Ischemic Stroke and Hemorrhagic Transformation

Stroke in China is distinguished by its high rates of morbidity, recurrence, disability, and mortality. The ultra-early administration of rtPA is essential for restoring perfusion in acute ischemic stroke, though it concurrently elevates the risk of hemorrhagic transformation. High-mobility group box 1 (HMGB1) emerges as a pivotal player in neuroinflammation after brain ischemia and ischemia-reperfusion. Released passively by necrotic cells and actively secreted, including direct secretion of HMGB1 into the extracellular space and packaging of HMGB1 into intracellular vesicles by immune cells, glial cells, platelets, and endothelial cells, HMGB1 represents a prototypical damage-associated molecular pattern (DAMP). It is intricately involved in the pathogenesis of atherosclerosis, thromboembolism, and detrimental inflammation during the early phases of ischemic stroke. Moreover, HMGB1 significantly contributes to neurovascular remodeling and functional recovery in later stages. Significantly, HMGB1 mediates hemorrhagic transformation by facilitating neuroinflammation, directly compromising the integrity of the blood-brain barrier, and enhancing MMP9 secretion through its interaction with rtPA. As a systemic inflammatory factor, HMGB1 is also implicated in post-stroke depression and an elevated risk of stroke-associated pneumonia. The role of HMGB1 extends to influencing the pathogenesis of ischemia by polarizing various subtypes of immune and glial cells. This includes mediating excitotoxicity due to excitatory amino acids, autophagy, MMP9 release, NET formation, and autocrine trophic pathways. Given its multifaceted role, HMGB1 is recognized as a crucial therapeutic target and prognostic marker for ischemic stroke and hemorrhagic transformation. In this review, we summarize the structure and redox properties, secretion and pathways, regulation of immune cell activity, the role of pathophysiological mechanisms in stroke, and hemorrhage transformation for HMGB1, which will pave the way for developing new neuroprotective drugs, reduction of post-stroke neuroinflammation, and expansion of thrombolysis time window.

Polyphyllin I alleviates neuroinflammation after cerebral ischemia-reperfusion injury via facilitating autophagy-mediated M2 microglial polarization

Microglial activation and polarization play a central role in poststroke inflammation and neuronal damage. Modulating microglial polarization from pro-inflammatory to anti-inflammatory phenotype is a promising therapeutic strategy for the treatment of cerebral ischemia. Polyphyllin I (PPI), a steroidal saponin, shows multiple bioactivities in various diseases, but the potential function of PPI in cerebral ischemia is not elucidated yet. In our study, the influence of PPI on cerebral ischemia-reperfusion injury was evaluated. Mouse middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation and reoxygenation (OGD/R) model were constructed to mimic cerebral ischemia-reperfusion injury in vivo and in vitro. TTC staining, TUNEL staining, RT-qPCR, ELISA, flow cytometry, western blot, immunofluorescence, hanging wire test, rotarod test and foot-fault test, open-field test and Morris water maze test were performed in our study. We found that PPI alleviated cerebral ischemia-reperfusion injury and neuroinflammation, and improved functional recovery of mice after MCAO. PPI modulated microglial polarization towards anti-inflammatory M2 phenotype in MCAO mice in vivo and post OGD/R in vitro. Besides, PPI promoted autophagy via suppressing Akt/mTOR signaling in microglia, while inhibition of autophagy abrogated the effect of PPI on M2 microglial polarization after OGD/R. Furthermore, PPI facilitated autophagy-mediated ROS clearance to inhibit NLRP3 inflammasome activation in microglia, and NLRP3 inflammasome reactivation by nigericin abolished the effect of PPI on M2 microglia polarization. In conclusion, PPI alleviated post-stroke neuroinflammation and tissue damage via increasing autophagy-mediated M2 microglial polarization. Our data suggested that PPI had potential for ischemic stroke treatment.

Panax notoginseng Saponins Activate Nuclear Factor Erythroid 2-Related Factor 2 to Inhibit Ferroptosis and Attenuate Inflammatory Injury in Cerebral Ischemia-Reperfusion

Panax notoginseng saponins (PNS), the primary medicinal ingredient of Panax notoginseng, mitigates cerebral ischemia-reperfusion injury (CIRI) by inhibiting inflammation, regulating oxidative stress, promoting angiogenesis, and improving microcirculation. Moreover, PNS activates nuclear factor erythroid 2-related factor 2 (Nrf2), which is known to inhibit ferroptosis and reduce inflammation in the rat brain. However, the molecular regulatory roles of PNS in CIRI-induced ferroptosis remain unclear. In this study, we aimed to investigate the effects of PNS on ferroptosis and inflammation in CIRI. We induced ferroptosis in SH-SY5Y cells via erastin stimulation and oxygen glucose deprivation/re-oxygenation (OGD/R) in vitro. Furthermore, we determined the effect of PNS treatment in a rat model of middle cerebral artery occlusion/reperfusion and assessed the underlying mechanism. We also analyzed the changes in the expression of ferroptosis-related proteins and inflammatory factors in the established rat model. OGD/R led to an increase in the levels of ferroptosis markers in SH-SY5Y cells, which were reduced by PNS treatment. In the rat model, combined treatment with an Nrf2 agonist, Nrf2 inhibitor, and PNS-Nrf2 inhibitor confirmed that PNS promotes Nrf2 nuclear localization and reduces ferroptosis and inflammatory responses, thereby mitigating brain injury. Mechanistically, PNS treatment facilitated Nrf2 activation, thereby regulating the expression of iron overload and lipid peroxidation-related proteins and the activities of anti-oxidant enzymes. This cascade inhibited ferroptosis and mitigated CIRI. Altogether, these results suggest that the ferroptosis-mediated activation of Nrf2 by PNS reduces inflammation and is a promising therapeutic approach for CIRI.

Effect of Cyclosporin H on ischemic injury and neutrophil infiltration in cerebral infarct model of rats via PET imaging

BACKGROUND

Brain ischemia-reperfusion injury is a complex process, and neuroinflammation is an important secondary contributing pathological event. Neutrophils play major roles in ischemic neuroinflammation. Once activated, neutrophils express formyl peptide receptors (FPRs), which are special receptors of a class of chemoattractants and may be potential targets to regulate the activity of neutrophils and control cerebral ischemic injury. This study was aimed to explore the ameliorating effect of Cyclosporin H (CsH), a potent FPR antagonist, on brain ischemic injury by inhibiting the activation and migration of neutrophils, and improving cerebral blood flow.

METHODS

We employed a middle cerebral artery occlusion (MCAO) Model on rats and performed behavioral, morphological, and microPET imaging assays to investigate the potential restoring efficacy of CsH on cerebral ischemic damages. Peptide N-cinnamoyl-F-(D)L-F-(D)L-F (cFLFLF), an antagonist to the neutrophil FPR with a high binding affinity, was used for imaging neutrophil distribution.

RESULTS

We found that CsH had similar effect with edaravone on improving the neurobehavioral deficient symptoms after cerebral ischemia-reperfusion, and treatment with CsH also alleviated ischemic cerebral infarction. Compared with the MCAO Model group, [18F]FDG uptake ratios of the CsH and edaravone treatment groups were significantly higher. The CsH-treated groups also showed significant increases in [18F]FDG uptake at 144 h when compared with that of 24 h. This result indicates that like edaravone, treatment with both doses of CsH promoted the recovery of blood supply after cerebral ischemic event. Moreover, MCAO-induced cerebral ischemia significantly increased the radiouptake of [68Ga]Ga-cFLFLF at 72 h after ischemia-reperfusion operation. Compared with MCAO Model group, radiouptake values of [68Ga]-cFLFLF in both doses of CsH and edaravone groups were all decreased significantly. These results showed that both doses of CsH resulted in a similar therapeutic effect with edaravone on inhibiting neutrophil infiltration in cerebral infarction.

CONCLUSION

Potent FPR antagonist CsH is promisingly beneficial in attenuating neuroinflammation and improving neurobehavioral function against cerebral infarction. Therefore, FPR may become a novel target for regulating neuroinflammation and improving prognosis for ischemic cerebrovascular disorders.

Oxidized mitochondrial DNA activates the cGAS-STING pathway in the neuronal intrinsic immune system after brain ischemia-reperfusion injury

In the context of stroke and revascularization therapy, brain ischemia-reperfusion injury is a significant challenge that leads to oxidative stress and inflammation. Central to the cell's intrinsic immunity is the cGAS-STING pathway, which is typically activated by unusual DNA structures. The involvement of oxidized mitochondrial DNA (ox-mtDNA)-an oxidative stress byproduct-in this type of neurological damage has not been fully explored. This study is among the first to examine the effect of ox-mtDNA on the innate immunity of neurons following ischemia-reperfusion injury. Using a rat model of transient middle cerebral artery occlusion and a cellular model of oxygen-glucose deprivation/reoxygenation, we have discovered that ox-mtDNA activates the cGAS-STING pathway in neurons. Importantly, pharmacologically limiting the release of ox-mtDNA into the cytoplasm reduces inflammation and improves neurological functions. Our findings suggest that targeting ox-mtDNA release may be a valuable strategy to attenuate brain ischemia-reperfusion injury following revascularization therapy for acute ischemic stroke.

Increasing expression of dual-specificity phosphatase 12 mitigates oxygen-glucose deprivation/reoxygenation-induced neuronal apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway

Dual-specificity phosphatase 12 (DUSP12) is abnormally expressed under various pathological conditions and plays a crucial role in the pathological progression of disorders. However, the role of DUSP12 in cerebral ischaemia/reperfusion injury has not yet been investigated. This study explored the possible link between DUSP12 and cerebral ischaemia/reperfusion injury using an oxygen-glucose deprivation/reoxygenation (OGD/R) model. Marked decreases in DUSP12 levels have been observed in cultured neurons exposed to OGD/R. DUSP12-overexpressed neurons were resistant to OGD/R-induced apoptosis and inflammation, whereas DUSP12-deficient neurons were vulnerable to OGD/R-evoked injuries. Further investigation revealed that DUSP12 overexpression or deficiency affects the phosphorylation of apoptosis signal-regulating kinase 1 (ASK1), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) in neurons under OGD/R conditions. Moreover, blockade of ASK1 diminished the regulatory effect of DUSP12 deficiency on JNK and p38 MAPK activation. In addition, DUSP12-deficiency-elicited effects exacerbating neuronal OGD/R injury were reversed by ASK1 blockade. In summary, DUSP12 protects against neuronal OGD/R injury by reducing apoptosis and inflammation through inactivation of the ASK1-JNK/p38 MAPK pathway. These findings imply a neuroprotective function for DUSP12 in cerebral ischaemia/reperfusion injury.

Role of the Insulin-like Growth Factor System in Neurodegenerative Disease

The insulin-like growth factor (IGF) system has paracrine and endocrine roles in the central nervous system. There is evidence that IGF signalling pathways have roles in the pathophysiology of neurodegenerative disease. This review focusses on Alzheimer's disease and Parkinson's disease, the two most common neurodegenerative disorders that are increasing in prevalence globally in relation to the aging population and the increasing prevalence of obesity and type 2 diabetes. Rodent models used in the study of the molecular pathways involved in neurodegeneration are described. However, currently, no animal model fully replicates these diseases. Mice with triple mutations in APP, PSEN and MAPT show promise as models for the testing of novel Alzheimer's therapies. While a causal relationship is not proven, the fact that age, obesity and T2D are risk factors in both strengthens the case for the involvement of the IGF system in these disorders. The IGF system is an attractive target for new approaches to management; however, there are gaps in our understanding that first need to be addressed. These include a focus beyond IGF-I on other members of the IGF system, including IGF-II, IGF-binding proteins and the type 2 IGF receptor.

Advanced Nano-Drug Delivery Systems in the Treatment of Ischemic Stroke

In recent years, the frequency of strokes has been on the rise year by year and has become the second leading cause of death around the world, which is characterized by a high mortality rate, high recurrence rate, and high disability rate. Ischemic strokes account for a large percentage of strokes. A reperfusion injury in ischemic strokes is a complex cascade of oxidative stress, neuroinflammation, immune infiltration, and mitochondrial damage. Conventional treatments are ineffective, and the presence of the blood-brain barrier (BBB) leads to inefficient drug delivery utilization, so researchers are turning their attention to nano-drug delivery systems. Functionalized nano-drug delivery systems have been widely studied and applied to the study of cerebral ischemic diseases due to their favorable biocompatibility, high efficiency, strong specificity, and specific targeting ability. In this paper, we briefly describe the pathological process of reperfusion injuries in strokes and focus on the therapeutic research progress of nano-drug delivery systems in ischemic strokes, aiming to provide certain references to understand the progress of research on nano-drug delivery systems (NDDSs).

Piezo1 Knockout Improves Post-Stroke Cognitive Dysfunction by Inhibiting the Interleukin-6 (IL-6)/Glutathione Peroxidase 4 (GPX4) Pathway

Background

Cerebral infarction often results in post-stroke cognitive impairment, which impairs the quality of life and causes long-term disability. Astrocytes, the most abundant glial cells in the central nervous system, have a crucial role in cerebral ischemia and neuroinflammation. We explored the possible advantages of interleukin-6 (IL-6), a powerful pro-inflammatory cytokine produced by astrocytes, for post-stroke cognitive function.

Methods

Mendelian randomization was applied to analyze the GWAS database of stroke patients, obtaining a causal relationship between IL-6 and stroke. Further validation of this relationship and its mechanisms was conducted. Using a mouse model of cerebral infarction, we demonstrated a significant increase in IL-6 expression in astrocytes surrounding the ischemic lesion. This protective effect of Piezo1 knockout was attributed to the downregulation of matrix metalloproteinases and upregulation of tight junction proteins, such as occludin and zonula occludens-1 (ZO-1).

Results

Two-step Mendelian randomization revealed that IL-6 exposure is a risk factor for stroke. Moreover, we conducted behavioral assessments and observed that Piezo1 knockout mice that received intranasal administration of astrocyte-derived IL-6 showed notable improvement in cognitive function compared to control mice. This enhancement was associated with reduced neuronal cell death and suppressed astrocyte activation, preserving ZO-1.

Conclusion

Our study shows that astrocyte-derived IL-6 causes cognitive decline after stroke by protecting the blood-brain barrier. This suggests that piezo1 knockout may reduce cognitive impairment after brain ischemia. Further research on the mechanisms and IL-6 delivery methods may lead to new therapies for post-stroke cognition.

Pharmacological inhibition of mTORC1 reduces neural death and damage volume after MCAO by modulating microglial reactivity

Ischemic stroke is a sudden and acute disease characterized by neuronal death, increment of reactive gliosis (reactive microglia and astrocytes), and a severe inflammatory process. Neuroinflammation is an early event after cerebral ischemia, with microglia playing a leading role. Reactive microglia involve functional and morphological changes that drive a wide variety of phenotypes. In this context, deciphering the molecular mechanisms underlying such reactive microglial is essential to devise strategies to protect neurons and maintain certain brain functions affected by early neuroinflammation after ischemia. Here, we studied the role of mammalian target of rapamycin (mTOR) activity in the microglial response using a murine model of cerebral ischemia in the acute phase. We also determined the therapeutic relevance of the pharmacological administration of rapamycin, a mTOR inhibitor, before and after ischemic injury. Our data show that rapamycin, administered before or after brain ischemia induction, reduced the volume of brain damage and neuronal loss by attenuating the microglial response. Therefore, our findings indicate that the pharmacological inhibition of mTORC1 in the acute phase of ischemia may provide an alternative strategy to reduce neuronal damage through attenuation of the associated neuroinflammation.

Autophagy-related 5 in acute ischemic stroke: Variation and linkage with neurofunction, and survival

OBJECTIVE

Autophagy-related 5 (ATG5) facilitates the pathologic process of acute ischemic stroke (AIS) via multiple ways. This study aimed to identify the association of serum ATG5 with clinical outcomes in AIS patients.

METHODS

Serum ATG5 from 280 AIS patients were detected at admission, Day (D)1, D3, D7, D30, and D90 after admission by enzyme-linked immunosorbent assay. The median (interquartile range) follow-up was 21.1 (5.9-43.9) months. Another 50 healthy controls (HCs) were also enrolled for serum ATG5 determination.

RESULTS

ATG5 was elevated (p < 0.001) (vs. HCs), and positively correlated with hyperlipidemia (p = 0.016), and the national institutes of health stroke scale score (p = 0.001) in AIS patients. Interestingly, ATG5 was increased from admission to D1, but gradually decreased until D90 (p < 0.001). Besides, 85 (30.4%) and 195 (69.6%) AIS patients were assessed as modified Rankin Scale (mRS) >2 and mRS ≤2 at D90, respectively. ATG5 at admission, D1, D3, D30, and D90 was elevated in AIS patients with mRS >2 versus those with mRS ≤2 (all p < 0.050). ATG5 at admission, D1, D3, D7, D30, or D90 was elevated in relapsed (vs. non-relapsed) or died (vs. survived) AIS patients (all p < 0.050). Recurrence-free survival was shortened in AIS patients with high (≥52.0 ng/mL) ATG5 versus those with low (<52.0 ng/mL) ATG5 at admission, D3, D7, and D30 (all p < 0.050); overall survival was shorter in AIS patients with high (vs. low) ATG5 at D7 and D30 (both p < 0.050).

INTERPRETATION

Serum ATG5 elevates at first, thereafter gradually declines, whose elevation associates with neurological dysfunction, recurrence, and death risk in AIS patients.

Suppression of microRNA-320 Induces Cerebral Protection Against Ischemia/Reperfusion Injury by Targeting HMGB1/NF-kappaB Axis

MicroRNAs have been shown to potentially function in cerebral ischemia/reperfusion (IR) injury. This study aimed to examine the expression of microRNA-320 (miR-320) in cerebral IR injury and its involvement in cerebral mitochondrial function, oxidative stress, and inflammatory responses by targeting the HMGB1/NF-kappaB axis. Sprague-Dawley rats were subjected to middle cerebral artery occlusion to simulate cerebral IR injury. The cerebral expression of miR-320 was assessed using qRT-PCR. Neurological function, cerebral infarct volume, mitochondrial function, oxidative stress, and inflammatory cytokines were evaluated using relevant methods, including staining, fluorometry, and ELISA. HMGB1 expression was analyzed through Western blotting. The levels of miR-320, HMGB1, neurological deficits, and cerebral infarction were significantly higher after IR induction. Intracerebral overexpression of miR-320 resulted in substantial neurological deficits, increased infarct volume, elevated levels of 8-isoprostane, NF-kappaBp65, TNF-alpha, IL-1beta, ICAM-1, VCAM-1, and HMGB1 expression. It also promoted the loss of mitochondrial membrane potential and ROS levels while reducing MnSOD and GSH levels. Downregulation of miR-320 and inhibition of HMGB1 activity significantly reversed the outcomes of cerebral IR injury. MiR-320 plays a negative role in regulating cerebral inflammatory/oxidative reactions induced by IR injury by enhancing HMGB1 activity and modulating mitochondrial function.

Effect of the Novel Free Radical Scavenger 4'-Hydroxyl-2-Substituted Phenylnitronyl Nitroxide on Oxidative Stress, Mitochondrial Dysfunction and Apoptosis Induced by Cerebral Ischemia-Reperfusion in Rats

Mitochondrial dysfunction, which results in the overproduction of oxygen free radicals, is a crucial mechanism underlying cerebral ischemia-reperfusion injury. 4'-Hydroxyl-2-substituted phenylnitronyl nitroxide (HPN), which is an antioxidant and free radical scavenger, can effectively scavenge oxygen free radicals, suggesting its potential as a protective agent against cerebral ischemia-reperfusion injury. In this study, we investigated the effects of HPN on mitochondrial function and apoptosis following cerebral ischemia/reperfusion injury in rats. Healthy adult SD rats were chosen as the experimental subjects, and the rat ischemia/reperfusion injury model was generated using the modified Zea Longa method. The administration of HPN significantly enhanced the activity of endogenous antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT). Additionally, HPN effectively preserved the morphology and function of mitochondria, reduced the protein and gene expression of Caspase-3 and Bax, increased the protein and gene expression of Bcl-2, mitigated neuronal apoptosis, improved neurological deficits, and decreased the volume of cerebral infarction. Of interest, the protective effect on brain tissue was more evident with increasing doses of HPN. These findings indicate that HPN can serve as an effective protective agent against cerebral ischemia-reperfusion injury.

Upregulation of TRPC1 in microglia promotes neutrophil infiltration after ischemic stroke

Neutrophil infiltration has been linked to worse clinical outcomes after ischemic stroke. Microglia, a key type of immune-competent cell, engage in cross-talk with the infiltrating immune cells in the inflamed brain area, yet the molecular mechanisms involved remain largely unexplored. In this study, we investigated the mechanisms of how canonical transient receptor potential 1 (TRPC1) modulated neutrophil infiltration in male mouse cerebral ischemia and reperfusion injury (CIRI) models. Our findings revealed a notable upregulation of TRPC1 in microglia within both middle cerebral artery occlusion reperfusion (MCAO/R) and in vitro oxygen-glucose deprivation/regeneration (OGD/R) model. Conditional Trpc1 knockdown in microglia markedly reduced infarct volumes and alleviated neurological deficits. Microglia conditional Trpc1 knockdown mice displayed less neutrophil infiltration in peri-infarct area. Trpc1 knockdown microglia exhibited a reduced primed proinflammatory phenotype with less secretion of CC-Chemokines ligand (CCL) 5 and CCL2 after MCAO/R. Blocking CCL5/2 significantly mitigated neutrophil infiltration in microglia/neutrophil transwell co-culture system upon OGD/R condition. Trpc1 knockdown markedly reduced store-operated calcium entry and nuclear factor of activated T-cells c1 (NFATc1) level in OGD/R treated microglia. Overexpression of Nfatc1 reversed the CCL5/2 reducing effect of Trpc1 knockdown, which is mediated by small interfering RNA in BV2 cells upon OGD/R. Our data indicate that upregulation of TRPC1 in microglia stimulates the production of CCL5/2 through the Ca2+/NFATc1 pathway. Upregulated CCL5/2 leads to an increase in neutrophil infiltration into the brain, thereby aggravating reperfusion injury. Our results demonstrate the importance of TRPC1 in microglia-mediated neuroinflammation and suggest a potential means for reducing CIRI induced neurological injury.

Therapeutic strategies targeting the NLRP3‑mediated inflammatory response and pyroptosis in cerebral ischemia/reperfusion injury (Review)

Ischemic stroke poses a major threat to human health. Therefore, the molecular mechanisms of cerebral ischemia/reperfusion injury (CIRI) need to be further clarified, and the associated treatment approaches require exploration. The NOD‑like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome serves an important role in causing CIRI, and its activation exacerbates the underlying injury. Activation of the NLRP3 inflammasome triggers the maturation and production of the inflammatory molecules IL‑1β and IL‑18, as well as gasdermin‑D‑mediated pyroptosis and CIRI damage. Thus, the NLRP3 inflammasome may be a viable target for the treatment of CIRI. In the present review, the mechanisms of the NLRP3 inflammasome in the intense inflammatory response and pyroptosis induced by CIRI are discussed, and the therapeutic strategies that target the NLRP3‑mediated inflammatory response and pyroptosis in CIRI are summarized. At present, certain drugs have already been studied, highlighting future therapeutic perspectives.

Nuciferine reduces inflammation induced by cerebral ischemia-reperfusion injury through the PI3K/Akt/NF-κB pathway

BACKGROUND

Cerebral ischemia has the characteristics of high incidence, mortality, and disability, which seriously damages people's health. Cerebral ischemia-reperfusion injury is the key pathological injury of this disease. However, there is a lack of drugs that can reduce cerebral ischemia-reperfusion injury in clinical practice. At present, a few studies have provided some evidence that nuciferine can reduce cerebral ischemia-reperfusion injury, but its specific mechanism of action is still unclear, and further research is still needed.

OBJECTIVE

In this study, PC12 cells and SD rats were used to construct OGD/R and MCAO/R models, respectively. Combined with bioinformatics methods and experimental verification methods, the purpose of this study was to conduct a systematic and comprehensive study on the effect and mechanism of nuciferine on reducing inflammation induced by cerebral ischemia-reperfusion injury.

RESULTS

Nuciferine can improve the cell viability of PC12 cells induced by OGD/R, reduce apoptosis, and reduce the expression of inflammation-related proteins; it can also improve the cognitive and motor dysfunction of MCAO/R-induced rats by behavioral tests, reduce the area of cerebral infarction, reduce the release of inflammatory factors TNF-α and IL-6 in serum and the expression of inflammation-related proteins in brain tissue.

CONCLUSION

Nuciferine can reduce the inflammatory level of cerebral ischemia-reperfusion injury in vivo and in vitro models by acting on the PI3K/Akt/NF-κB signaling pathway, and has the potential to be developed as a drug for the treatment of cerebral ischemia-reperfusion injury.