Advances in stroke pharmacology

Circulatory factors in stroke protection and recovery

Over the past decade, the management of acute ischemic stroke has undergone a paradigm shift, especially a longer time-window and a wider indication for endovascular treatments. However, many patients still have long-term dysfunction despite the best medical care at present. Based on findings from innovative proteomic and transcriptomic technologies, researchers have identified an array of novel or previously underappreciated circulatory factors that play pivotal roles in mediating post-injuries brain communication. Thus, the previous concept of the brain as a privileged compartment isolated from the rest of the body has been replaced by the novel consensus that brain bidirectionally interacts with the other organs after brain diseases. In this review, we make a summary of several axes that connect the brain with the rest of the body after stroke. More importantly, we summarize several circulatory factors that play pivotal roles in fostering post-stroke functional recovery in the chronic stage. Special attention is given to the instrumental role of circulatory signals, positing them as significant contributors to the complex process of brain function recovery and as translational therapeutic targets for ischemic stroke in future studies.

Kaempferol promotes angiogenesis through HIF-1α/VEGF-A/Notch1 pathway in ischemic stroke rats

Stroke is a severe disease characterized by the obstruction of blood vessels in the central nervous system. An essential therapeutic strategy for ischemic stroke is strengthening angiogenesis, which effectively promotes the long-term recovery of neurological function. Therefore, it is critical to explore and develop new drugs that promote angiogenesis after ischemic stroke. Kaempferol has been employed to treat ischemic diseases; However, its proangiogenic effects in ischemic stroke remain unclear. In the study, we explored the long-term therapeutic effects and mechanisms of kaempferol on ischemic stroke in vivo and in vitro. A rat model of autologous thrombus stroke and oxygen-glucose deprivation (OGD)-induced human brain microvascular endothelial cells (HBMECs) model was established to assess the effects of kaempferol in vivo (50 mg/kg/d, ig, 14 d) and in vitro (0.1, 0.3, 1 μmol L-1). The results showed that long-term administration of kaempferol ameliorated neurological deficits and infarct volume in ischemic stroke rats. In addition, kaempferol relieved vascular embolization; enhanced microvascular endothelial cell survival, proliferation, migration, and lumen formation; increased the density of microvessels in the peri-infarct cortex; and promoted neovascular structure remodeling by increasing the coverage of astrocyte end-feet and expression of tight-junction proteins (TJPs). Further analysis revealed that the HIF-1α/VEGF-A/Notch1 signaling pathway was activated by kaempferol, and that inhibition of Notch1 blocked kaempferol-induced angiogenesis. Taken together, our results indicate that kaempferol exerts neuroprotective effects by stimulating endogenous angiogenesis and neovascular structural remodeling via the HIF-1α/VEGF-A/Notch1 signaling pathway, suggesting the therapeutic potential of kaempferol in ischemic stroke.

Potential edaravone/benzocyclopentenone derivatives alleviate cerebral ischemia reperfusion injury as neuroprotective agents

Based on the scaffold of edaravone, a clinically approved neuroprotective agent, a series of edaravone/benzocyclopentenone hybrid derivatives were designed, synthesized and evaluated for their biological activities in vitro and in vivo. Most of the compounds demonstrated promising neuroprotective effects, with derivatives containing benzofuranone or indanone as core moiety showing particularly strong activity. Among all derivatives, 17 compounds exhibited significantly improved neuronal cell viabilities compared to edaravone in an OGD/R model with rat primary neuronal cells, along with favorable safety profiles and blood-brain barrier permeability. Notably, compound 13, which includes a fluoro-substituted benzofuranone fragment, displayed the most potent neuroprotective effect in vitro and effectively reduced cerebral infarct area in vivo.

Baicalin improves neurological outcomes in mice with ischemic stroke by inhibiting astrocyte activation and neuroinflammation

OBJECTIVE

The inflammatory response is integral to all stages of ischemic stroke. Unlike conventional reperfusion therapies, anti-inflammatory strategies offer a broader therapeutic window for treating ischemic stroke due to their capacity to attenuate inflammation. Astrocytes, once activated in ischemic conditions, significantly contribute to the production of inflammatory cytokines and exacerbate brain damage. While the neuroprotective effects of baicalin in post-stroke patients have been recognized, its role in modulating astrocyte activity and reducing inflammation remains under debate. This study aims to evaluate the impact of baicalin on astrocyte activation following ischemic stroke.

METHODS

A model of ischemia/reperfusion (I/R) injury was induced in wild-type mice through transient middle cerebral artery occlusion (tMCAO). Mice were randomized into groups receiving either baicalin or saline. The expression levels of inflammatory markers-interleukin (IL)-6, IL-1β, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-alpha (TNF-α)-were quantified using enzyme-linked immunosorbent assay (ELISA). Additionally, western blot analysis was employed to assess glial fibrillary acidic protein (GFAP) expression.

RESULTS

Baicalin administration significantly mitigated neurological deficits in mice post-tMCAO. It reduced the activation of astrocytes and the production of pro-inflammatory cytokines such as IL-6, IL-1β, TNF-α, and MCP-1, observed both in vivo and in vitro. In vitro studies also indicated a suppression of NF-κB activation.

CONCLUSION

Baicalin effectively prevents ischemic brain damage by curtailing neuroinflammation and astrocyte activation. These findings advance the understanding of baicalin's mechanistic role in mitigating brain ischemia and support further investigation into its therapeutic potential.

Astragaloside IV plays a neuroprotective role by promoting PPARγ in cerebral ischemia-reperfusion rats

BACKGROUND

Cerebral ischemia-reperfusion injury (CIRI) usually occurs during the treatment phase of ischemic disease, which is closely related to high morbidity and mortality. Promoting neurogenesis and synaptic plasticity are effective neural recovery strategies for CIRI. Astragaloside IV (AS-IV) has been shown to play a neuroprotective role in some neurological diseases. In the current study, we evaluated the effect and possible mechanism of AS-IV in CIRI rats.

METHODS

The middle cerebral artery occlusion reperfusion (MCAO/R) model was established in rats to simulate the occurrence of human CIRI. First, we determined the cerebral injury on the 1st, 3rd, 5th and 7th day after cerebral ischemia-reperfusion (I/R) surgery by neurological deficit detection, TTC staining, TUNEL staining and Western blot analysis. Furthermore, rats were pre administered with AS-IV and then subjected to cerebral I/R surgery. Brains were collected on the 3rd day to evaluate the neuroprotective effect of AS-IV.

RESULTS

Our results showed that on the 3rd day after I/R, the neurological impairment score and infarct volume were highest, the levels of apoptosis and expression of Caspase3 and Bax reached the peak. AS-IV treatment apparently attenuated neurological dysfunction, reduced infarct volume and pathological damage, promoted the neurogenesis, and alleviated the pathological damage caused by cerebral I/R involved in thickening and blurring of synaptic membranes, reduction of microtubules and synaptic vesicles, and loss of synaptic cleft. Our study also showed that AS-IV promoted the transcription and expression of the peroxisome proliferators-activated receptors γ (PPARγ) and brain-derived neurotrophic factor (BDNF), increased the expression of phosphorylation of tyrosine kinase receptor B (TrkB) and downstream PI3K/Akt/mTOR pathway proteins. Notably, when GW9662, an inhibitor of PPARγ was administered with AS-IV, the neuroprotective effect of AS-IV was reduced.

CONCLUSIONS

These findings suggested that AS-IV has neuroprotective function in CIRI rats, and its molecular mechanism may depend on the phosphatidylinositide 3-kinase (PI3K)/protein kinase B (PKB)/Akt signalling pathway activated by PPARγ. AS-IV could be an effective therapeutic drug candidate for CIRI treatment.

A multiple targeting rapamycin and SS31 conjugate enhances ischemic stroke therapy

BACKGROUND

The identification of drugs targeting multiple pathways is essential for comprehensive protection against cerebral ischemia-reperfusion injury.

RESEARCH DESIGN AND METHODS

This study aimed to develop RS31, a multi-target cytoprotectant composed of SS31 (an oxidative stress mitigator) and rapamycin (Rapa), contributes anti-inflammatory and blood-brain barrier protection. RS31 was synthesized using click chemistry, and its ability to scavenge reactive oxygen species (ROS) and reduce inflammation was tested in H2O2-injured PC12 cells and LPS-stimulated BV2 cells. A C57BL/6 mouse model of transient middle cerebral artery occlusion/reperfusion (tMCAO/R) was established to assess the effect of RS31 on inflammatory factors in ischemic brain tissue. Finally, the potential of combining RS31 with PLGA microparticles (MPs) to further reduce brain edema was investigated.

RESULTS

RS31 effectively scavenged ROS and reduced inflammation. It showed a ~ 4-fold higher concentration in cerebral ischemic regions, significant reducing infarction and improving neurological function. RS31 also effectively reduced inflammatory factors, lowered malondialdehyde (MDA) levels, and increased superoxide dismutase (SOD) activity, showing strong efficacy in treating ischemic stroke.

CONCLUSIONS

In vivo delivery of RS31 is an effective therapeutic strategy for I/R injury, providing a general framework for developing multi-targeted drugs against inflammatory diseases and excessive ROS production.

The therapeutic effects of salvianolic acids on ischemic stroke: From molecular mechanisms to clinical applications

Ischemic stroke (IS), primarily caused by cerebrovascular occlusion, poses a significant public health challenge with limited effective therapeutic options. Evidence suggests that salvianolic acids (SAs), mainly from Salvia miltiorrhiza Bunge, have been formulated into injections and are widely used in clinical treatments for cardiovascular and cerebrovascular diseases, including stroke. The pharmacological properties of SAs include reducing neuroinflammation, alleviating oxidative stress injury, inhibiting cellular apoptosis, preserving endothelial function, maintaining blood-brain barrier integrity, and promoting angiogenesis. Salvianolic acids for injection (SAFI) serve as a safe and effective treatment option for cardiovascular and cerebrovascular conditions by influencing various signaling pathways and molecular targets associated with these diseases. In this review, we first discuss the pathogenesis of IS, then summarize the classification of SAs, elaborate detailed molecular mechanisms of their efficacy, and the related clinical applications of SAFI. We also emphasize the recent pharmacological advancements and therapeutic possibilities of this promising drug preparation derived from herbs for cerebrovascular conditions.

Beyond Pharmacology: The Biological Mechanisms of Remote Ischemic Conditioning in Cerebrovascular Disease

Cerebrovascular diseases (CVDs), comprising predominantly ischemic stroke and chronic cerebral hypoperfusion (CCH), are a significant threat to global health, often leading to disability and mortality. Remote ischemic conditioning (RIC) has emerged as a promising, non-pharmacological strategy to combat CVDs by leveraging the body's innate defense mechanisms. This review delves into the neuroprotective mechanisms of RIC, categorizing its effects during the acute and chronic phases of stroke recovery. It also explores the synergistic potential of RIC when combined with other therapeutic strategies, such as pharmacological treatments and physical exercise. Additionally, this review discusses the pathways through which peripheral transmission can confer central neuroprotection. This review concludes by addressing the challenges regarding and future directions for RIC, emphasizing the need for standardized protocols, biomarker identification, and expanded clinical trials to fully realize its therapeutic potential.

Dynamic changes in Beclin-1, LC3B, and p62 in aldose reductase-knockout mice at different time points after ischemic stroke

Ischemic stroke is a brain injury caused by cerebral blood circulation disorders and is closely related to oxidative stress. Aldose reductase (AR) is a critical enzyme involved in oxidative stress. Autophagy has previously been found to play a key role in cerebral ischemia‒reperfusion injury. However, it is still unclear how autophagy molecules change after cerebral ischemia‒reperfusion injury in AR knockout mice (AR-/-). A transient middle cerebral artery occlusion (tMCAO) model was generated in AR-/- mice, and the neurological deficit scores of the mice were observed and recorded on Days 1, 3 and 5 after tMCAO. Neuronal damage in the ischemic penumbra was observed by TTC, HE, and Nissl staining. The expression of the autophagy-related molecules Beclin-1, LC3II/I, and P62 as well as that of molecules related to inflammation, oxidative stress, and neurological damage was detected by RT‒qPCR, western blotting, and immunofluorescence. Autophagosomes were observed using a transmission electron microscope. Cerebral ischemia‒reperfusion injury caused neurological deficits and ischemic infarction in tMCAO mice (P < 0.01). Beclin-1, Bcl2/Bax, SOD, GSH-px, P62, PSD95, and TOM20 levels decreased (P < 0.05), while IL-6, LC3II/I, and GFAP levels increased (P < 0.01) in the AR-/- tMCAO-1d group and the AR-/- tMCAO-3d group, compared to those in the sham group. Beclin-1, Bcl2/Bax, NOX4, GSH-px, P62, and PSD95 levels increased (P < 0.01), while IL-6, LC3II/I, and GFAP levels decreased (P < 0.01) in the AR-/- tMCAO-5d group compared to those in the AR-/- tMCAO-1d group. Autophagosome formation was observed in tMCAO mice. In summary, the changes in autophagy proteins in the brain tissue of the AR-/- mice after tMCAO were more obvious on Days 1 and 3 after tMCAO. The expression of Beclin-1 and P62 decreased, and the expression of LC3B increased after cerebral ischemia‒reperfusion injury in AR-/- mouse brain tissue.

Discovery of orally bioavailable phenyltetrazolium derivatives for the acute treatment and the secondary prevention of ischemic stroke

The potential for secondary stroke prevention, which can significantly reduce the risk of recurrent strokes by almost 90%, underscores its critical importance. N-butylphthalide (NBP) has emerged as a promising treatment for acute cerebral ischemia, yet its efficacy for secondary stroke prevention is hindered by inadequate pharmacokinetic properties. This study, driven by a comprehensive structural analysis, the iterative process of structure optimization culminated in the identification of compound B4, which demonstrated exceptional neuroprotective efficacy and remarkable oral exposure and oral bioavailability. Notably, in an in vivo transient middle cerebral artery occlusion (tMCAO) model, B4 substantially attenuated infarct volumes, surpassing the effectiveness of NBP. While oral treatment with B4 exhibited stronger prevention potency than NBP in photothrombotic (PT) model. In summary, compound B4, with its impressive oral bioavailability and potent neuroprotective effects, offers promise for both acute ischemic stroke treatment and secondary stroke prevention.

Src inhibition rescues FUNDC1-mediated neuronal mitophagy in ischaemic stroke

BACKGROUND

Ischaemic stroke triggers neuronal mitophagy, while the involvement of mitophagy receptors in ischaemia/reperfusion (I/R) injury-induced neuronal mitophagy remain not fully elucidated. Here, we aimed to investigate the involvement of mitophagy receptor FUN14 domain-containing 1 (FUNDC1) and its modulation in neuronal mitophagy induced by I/R injury.

METHODS

Wild-type and FUNDC1 knockout mice were generated to establish models of neuronal I/R injury, including transient middle cerebral artery occlusion (tMCAO) in vivo and oxygen glucose deprivation/reperfusion in vitro. Stroke outcomes of mice with two genotypes were assessed. Neuronal mitophagy was analysed both in vivo and in vitro. Activities of FUNDC1 and its regulator Src were evaluated. The impact of Src on FUNDC1-mediated mitophagy was assessed through administration of Src antagonist PP1.

RESULTS

To our surprise, FUNDC1 knockout mice subjected to tMCAO showed stroke outcomes comparable to those of their wild-type littermates. Although neuronal mitophagy could be activated by I/R injury, FUNDC1 deletion did not disrupt neuronal mitophagy. Transient activation of FUNDC1, represented by dephosphorylation of Tyr18, was detected in the early stages (within 3 hours) of neuronal I/R injury; however, phosphorylated Tyr18 reappeared and even surpassed baseline levels in later stages (after 6 hours), accompanied by a decrease in FUNDC1-light chain 3 interactions. Spontaneous inactivation of FUNDC1 was associated with Src activation, represented by phosphorylation of Tyr416, which changed in parallel with the level of phosphorylated FUNDC1 (Tyr18) during neuronal I/R injury. Finally, FUNDC1-mediated mitophagy in neurons under I/R conditions can be rescued by pharmacological inhibition of Src.

CONCLUSIONS

FUNDC1 is inactivated by Src during the later stage (after 6 hours) of neuronal I/R injury, and rescue of FUNDC1-mediated mitophagy may serve as a potential therapeutic strategy for treating ischaemic stroke.

Recent Advances and Therapeutic Implications of 2-Oxoglutarate-Dependent Dioxygenases in Ischemic Stroke

Ischemic stroke is a common disease with a high disability rate and mortality, which brings heavy pressure on families and medical insurance. Nowadays, the golden treatments for ischemic stroke in the acute phase mainly include endovascular therapy and intravenous thrombolysis. Some drugs are used to alleviate brain injury in patients with ischemic stroke, such as edaravone and 3-n-butylphthalide. However, no effective neuroprotective drug for ischemic stroke has been acknowledged. 2-Oxoglutarate-dependent dioxygenases (2OGDDs) are conserved and common dioxygenases whose activities depend on O2, Fe2+, and 2OG. Most 2OGDDs are expressed in the brain and are essential for the development and functions of the brain. Therefore, 2OGDDs likely play essential roles in ischemic brain injury. In this review, we briefly elucidate the functions of most 2OGDDs, particularly the effects of regulations of 2OGDDs on various cells in different phases after ischemic stroke. It would also provide promising potential therapeutic targets and directions of drug development for protecting the brain against ischemic injury and improving outcomes of ischemic stroke.

Ischemic stroke pathophysiology: A bibliometric and visualization analysis from 1990 to 2022

Background

Pathophysiology plays a significant role in the scientific study of ischemic stroke, and has attracted increasing interest from researchers in the field. However, a comprehensive bibliometric analysis is lacking in this field. The purpose of this study is to identify the current research status and hotspots of ischemic stroke pathophysiology from a bibliometric perspective.

Methods

The Web of Science Core Collection database was searched for articles published from 1990 to 2022. CiteSpace, VOSviewer, and R package "bibliometrix" software were used to analyze countries/regions, institutions, journals, authors, papers, and keywords to predict the latest trends in ischemic stroke pathophysiology research.

Results

This analysis collected 7578 records of ischemic stroke pathophysiology. China and America emerged as the leading countries in this field, with Harvard University being the most active institution. Among journals and authors in this field, journal Stroke and author Gregory YH Lip published the most papers, while Nature Medicine was the journal with the highest citation per article. Keywords and co-citation clusters were closely related to "central nervous system", "mechanisms", "biochemistry & molecular biology" and "radiology, nuclear medicine & medical imaging", while other related fields, such as peripheral organs damage induced by the central nervous system and rehabilitation after ischemic stroke, require further research efforts.

Conclusion

This is the first bibliometric study that comprehensively mapped out the knowledge structure and development trends of ischemic stroke pathophysiology in recent 32 years, which may provide a reference for scholars to explore ischemic stroke pathophysiology.

Neuroprotective role of lactate in a human in vitro model of the ischemic penumbra

In patients suffering from cerebral ischemic stroke, there is an urgent need for treatments to protect stressed yet viable brain cells. Recently, treatment strategies that induce neuronal activity have been shown to be neuroprotective. Here, we hypothesized that neuronal activation might maintain or trigger the astrocyte-to-neuron lactate shuttle (ANLS), whereby lactate is released from astrocytes to support the energy requirements of ATP-starved hypoxic neurons, and this leads to the observed neuroprotection. We tested this by using a human cell based in vitro model of the ischemic penumbra and investigating whether lactate might be neuroprotective in this setting. We found that lactate transporters are involved in the neuroprotective effect mediated by neuronal activation. Furthermore, we showed that lactate exogenously administered before hypoxia correlated with neuroprotection in our cellular model. In addition, stimulation of astrocyte with consequent endogenous production of lactate resulted in neuroprotection. To conclude, here we presented evidence that lactate transport into neurons contributes to neuroprotection during hypoxia providing a potential basis for therapeutic approaches in ischemic stroke.

HRV-guided training vs traditional HIIT training in cardiac rehabilitation: a randomized controlled trial

High-intensity interval training is the gold standard for cardiac rehabilitation although current revascularization therapy focuses on the recovery of autonomic nervous system balance through heart rate variability (HRV). The main objective was to analyze the effect of HRV-guided training versus high-intensity interval training on cardiorespiratory fitness, heart rate variability, quality of life, and training volume at high intensity, as well as exercise adherence, safety, and feasibility in ischemic patients. This is an 8-week cluster randomized controlled trial with an HRV-based training group (HRV-G) and a traditional HIIT group (HIIT-G). Maximal oxygen consumption, heart rate, and blood pressure were measured during the Bruce protocol treadmill test. HRV was measured with the HRV4Training application, and quality of life with the MacNew QLMI. The repeated measures ANCOVA was used with the age and the baseline scores as covariables. Forty-six patients (mean age 55 ± 11.03 years) were randomized and assigned either to HRV-G (n = 23) or HIIT-G (n = 23). Both groups improved maximal oxygen consumption and METS (P > .05). However, the resting systolic blood pressure was lower in HRV-G (4.3 ± 1.2 mmHg, P = .05). In HRV-G, the resting diastolic, maximal diastolic, and systolic blood pressure decreased (5.4 ± 5.96 mmHg, P = .007; 11.4 ± 12.46 mmHg, P = .005; and 5 ± 5.98 mmHg, P = .013, respectively) whereas the recovery heart rate increased significantly (-21.5 ± 23.16 beats/min, P = .003). The LnrMSSDcv ([LnrMSSDSD/LnrMSSDMEAN] × 100) was lower in HRV-G (1.23 ± 0.91 mmHg, P = .03) while the training volume at high intensity was higher in HIIT-G (31.4 ± 29.2 min, P = .024). HRV-guided training presents a better cardioprotective effect than HIIT-G at a lower high-intensity training volume.

Design, Synthesis, and Biological Evaluation of Pierardine Derivatives as Novel Brain-Penetrant and In Vivo Potent NMDAR-GluN2B Antagonists for Ischemic Stroke Treatment

A series of structurally novel GluN2B NMDAR antagonists were designed, synthesized, and biologically evaluated as anti-stroke therapeutics by optimizing the chemical structure of Pierardine, the active ingredient of traditional Chinese medicine Dendrobium aphyllum (Roxb.) C. E. Fischer identified via in silico screening. The systematic structure-activity relationship study led to the discovery of 58 with promising NMDAR-GluN2B binding affinity and antagonistic activity. Of the two enantiomers, S-58 exhibited significant inhibition (IC50 = 74.01 ± 12.03 nM) against a GluN1/GluN2B receptor-mediated current in a patch clamp assay. In addition, it displayed favorable specificity over other subtypes and off-target receptors. In vivo, S-58 exerted therapeutic efficacy comparable to that of the approved GluN2B NMDAR antagonist ifenprodil and excellent safety profiles. In addition to the attractive in vitro and in vivo potency, S-58 exhibited excellent brain exposure. In light of these merits, S-58 has been advanced to further preclinical investigation as a potential anti-stroke candidate.

Salvianolic acid C attenuates cerebral ischemic injury through inhibiting neuroinflammation via the TLR4-TREM1-NF-κB pathway

BACKGROUND

Stroke is a leading cause of mortality and disability with ischemic stroke being the most common type of stroke. Salvianolic acid C (SalC), a polyphenolic compound found in Salviae Miltiorrhizae Radix et Rhizoma, has demonstrated therapeutic potential in the recovery phase of ischemic stroke. However, its pharmacological effects and underlying mechanisms during the early stages of ischemic stroke remain unclear. This study aimed to examine the potential mechanism of action of SalC during the early phase of ischemic stroke using network pharmacology strategies and RNA sequencing analysis.

METHODS

SalC effects on infarct volume, neurological deficits, and histopathological changes were assessed in a mouse model of transient middle cerebral artery occlusion (tMCAO). By integrating RNA sequencing data with a cerebral vascular disease (CVD)-related gene database, a cerebral ischemic disease (CID) network containing dysregulated genes from the tMCAO model was constructed. Network analysis algorithms were applied to evaluate the key nodes within the CID network. In vivo and in vitro validation of crucial targets within the identified pathways was conducted.

RESULTS

SalC treatment significantly reduced infarct volume, improved neurological deficits, and reversed pathological changes in the tMCAO mouse model. The integration of RNA sequencing data revealed an 80% gene reversion rate induced by SalC within the CID network. Among the reverted genes, 53.1% exhibited reversion rates exceeding 50%, emphasizing the comprehensive rebalancing effect of SalC within the CID network. Neuroinflammatory-related pathways regulated by SalC, including the toll-like-receptor 4 (TLR4)- triggering receptor expressed on myeloid cells 1 (TREM1)-nuclear factor kappa B (NF-κB) pathway, were identified. Further in vivo and in vitro experiments confirmed that TLR4-TREM1-NF-κB pathway was down-regulated by SalC in microglia, which was essential for its anti-inflammatory effect on ischemic stroke.

CONCLUSIONS

SalC attenuated cerebral ischemic injury by inhibiting neuroinflammation mediated by microglia, primarily through the TLR4-TREM1-NF-κB pathway. These findings provide valuable insights into the potential therapeutic benefits of SalC in ischemic stroke.

A microthrombus-driven fixed-point cleaved nanosystem for preventing post-thrombolysis recurrence via inhibiting ferroptosis

Thrombus-induced cardiovascular diseases threaten human health. Current treatment strategies often rely on urokinase plasminogen activator (uPA) for its efficacy, yet it has such limiting factors as short half-life, lack of thrombus targeting, and systemic side effects leading to unintended bleeding. In addition, thrombolytic interventions can trigger inflammation-induced damage at thrombus sites, which affects endothelial function. To address these challenges, Fer-1/uPA@pep-CREKA-Lipo (Fu@pep-CLipo) has been developed. This system achieves precise and efficient thrombolysis while enhancing the thrombus microenvironment and mitigating ischemia-reperfusion injury, with exceptional thrombus targeting ability via the strong affinity of the Cys-Arg-Glu-Lys-Ala (CREKA) peptide for fibrin. The Cys-Nle-TPRSFL-DSPE (pep) could respond to the thrombus microenvironment and fixed-point cleavage. The uPA component linked to the liposome surface is strategically cleaved upon exposure to abundant thrombin at thrombus sites. Importantly, the inclusion of Fer-1 within Fu@pep-CLipo contributes to reactive oxygen species (ROS) scavenging and significantly improves the thrombus microenvironment. This innovative approach not only achieves highly efficient and precise thrombolysis but also positively influences the expression of eNOS protein while suppressing inflammatory factors like TNF-α and IL-6. This dual action contributes to improved thrombus inflammatory microenvironment and mitigated ischemia-reperfusion injury.

Visualizing Wallerian degeneration in the corticospinal tract after sensorimotor cortex ischemia in mice

Stroke can cause Wallerian degeneration in regions outside of the brain, particularly in the corticospinal tract. To investigate the fate of major glial cells and axons within affected areas of the corticospinal tract following stroke, we induced photochemical infarction of the sensorimotor cortex leading to Wallerian degeneration along the full extent of the corticospinal tract. We first used a routine, sensitive marker of axonal injury, amyloid precursor protein, to examine Wallerian degeneration of the corticospinal tract. An antibody to amyloid precursor protein mapped exclusively to proximal axonal segments within the ischemic cortex, with no positive signal in distal parts of the corticospinal tract, at all time points. To improve visualization of Wallerian degeneration, we next utilized an orthograde virus that expresses green fluorescent protein to label the corticospinal tract and then quantitatively evaluated green fluorescent protein-expressing axons. Using this approach, we found that axonal degeneration began on day 3 post-stroke and was almost complete by 7 days after stroke. In addition, microglia mobilized and activated early, from day 7 after stroke, but did not maintain a phagocytic state over time. Meanwhile, astrocytes showed relatively delayed mobilization and a moderate response to Wallerian degeneration. Moreover, no anterograde degeneration of spinal anterior horn cells was observed in response to Wallerian degeneration of the corticospinal tract. In conclusion, our data provide evidence for dynamic, pathogenic spatiotemporal changes in major cellular components of the corticospinal tract during Wallerian degeneration.

Traditional Chinese Medicine formula, Sanwujiao granule, attenuates ischemic stroke by promoting angiogenesis through early administration

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke (IS) is one of the most lethal diseases with the insufficient pharmacology therapeutic approach. Sanwujiao granule (SW) is widely used for IS in China with little known about its underlying mechanism.

AIM OF THE STUDY

To investigate the characteristics of therapeutic effects and potential mechanisms of SW against IS.

MATERIALS AND METHODS

The fingerprint of SW was applied by high-performance liquid chromatography-mass spectrometry (HPLC-MS). Three different drug treatment strategies, including prophylactic administration, early administration and delayed administration, were applied in rats' permanent middle cerebral occlusion (pMCAO) model. The Garcia neurological deficit test, adhesive removal test, rotarod test, TTC and TUNEL staining were performed to evaluate the pathological changes. The transcriptomic analysis was used to predict the potential mechanism of SW. The vascular deficiency model of Tg(kdrl:eGFP) zebrafish larvae and oxygen-glucose deprivation model on bEnd.3 cells were used to verify SW's pharmacological effect. qRT-PCR, immunofluorescent staining and Western Blot were applied to detect the expression of genes and proteins. The network pharmacology approach was applied to discover the potential bioactive compounds in SW that contribute to its pharmacological effect.

RESULTS

SW early and delayed administration attenuated cerebral infarction, neurological deficit and cell apoptosis. The transcriptomic analysis revealed that SW activated angiogenesis-associated biological processes specifically by early administration. CD31 immunofluorescent staining further confirmed the microvessel intensity in peri-infarct regions was significantly elevated after SW early treatment. Additionally, on the vascular deficiency model of zebrafish larvae, SW showed the angiogenesis effect. Next, the cell migration and tube formation were also observed in the bEnd.3 cells with the oxygen-glucose deprivation induced cell injury. It's worth noting that both mRNA and protein levels of angiogenesis factor, insulin-like growth factor 1, were significantly elevated in the pMCAO rats' brains treated with SW. The network pharmacology approach was applied and chasmanine, karacoline, talatisamine, etc. were probably the main active compounds of SW in IS treatment as they affected the angiogenesis-associated targets.

CONCLUSIONS

These results demonstrate that SW plays a critical role in anti-IS via promoting angiogenesis through early administration, indicating that SW is a candidate herbal complex for further investigation in treating IS in the clinical.

Novel insight into the therapeutical potential of flavonoids from traditional Chinese medicine against cerebral ischemia/reperfusion injury

Cerebral ischemia/reperfusion injury (CIRI) is a major contributor to poor prognosis of ischemic stroke. Flavonoids are a broad family of plant polyphenols which are abundant in traditional Chinese medicine (TCM) and have beneficial effects on several diseases including ischemic stroke. Accumulating studies have indicated that flavonoids derived from herbal TCM are effective in alleviating CIRI after ischemic stroke in vitro or in vivo, and exhibit favourable therapeutical potential. Herein, we systematically review the classification, metabolic absorption, neuroprotective efficacy, and mechanisms of TCM flavonoids against CIRI. The literature suggest that flavonoids exert potential medicinal functions including suppressing excitotoxicity, Ca2+ overloading, oxidative stress, inflammation, thrombin's cellular toxicity, different types of programmed cell deaths, and protecting the blood-brain barrier, as well as promoting neurogenesis in the recovery stage following ischemic stroke. Furthermore, we identified certain matters that should be taken into account in future research, as well as proposed difficulties and opportunities in transforming TCM-derived flavonoids into medications or functional foods for the treatment or prevention of CIRI. Overall, in this review we aim to provide novel ideas for the identification of new prospective medication candidates for the therapeutic strategy against ischemic stroke.

Systematic review of melatonin in cerebral ischemia-reperfusion injury: critical role and therapeutic opportunities

Cerebral ischemia-reperfusion (I/R) injury is the predominant causes for the poor prognosis of ischemic stroke patients after reperfusion therapy. Currently, potent therapeutic interventions for cerebral I/R injury are still very limited. Melatonin, an endogenous hormone, was found to be valid in preventing I/R injury in a variety of organs. However, a systematic review covering all neuroprotective effects of melatonin in cerebral I/R injury has not been reported yet. Thus, we perform a comprehensive overview of the influence of melatonin on cerebral I/R injury by collecting all available literature exploring the latent effect of melatonin on cerebral I/R injury as well as ischemic stroke. In this systematic review, we outline the extensive scientific studies and summarize the beneficial functions of melatonin, including reducing infarct volume, decreasing brain edema, improving neurological functions and attenuating blood-brain barrier breakdown, as well as its key protective mechanisms on almost every aspect of cerebral I/R injury, including inhibiting oxidative stress, neuroinflammation, apoptosis, excessive autophagy, glutamate excitotoxicity and mitochondrial dysfunction. Subsequently, we also review the predictive and therapeutic implications of melatonin on ischemic stroke reported in clinical studies. We hope that our systematic review can provide the most comprehensive introduction of current advancements on melatonin in cerebral I/R injury and new insights into personalized diagnosis and treatment of ischemic stroke.

Effect of salidroside on neuroprotection and psychiatric sequelae during the COVID-19 pandemic: A review

The coronavirus disease 2019 (COVID-19) pandemic has affected the mental health of individuals worldwide, and the risk of psychiatric sequelae and consequent mental disorders has increased among the general population, health care workers and patients with COVID-19. Achieving effective and widespread prevention of pandemic-related psychiatric sequelae to protect the mental health of the global population is a serious challenge. Salidroside, as a natural agent, has substantial pharmacological activity and health effects, exerts obvious neuroprotective effects, and may be effective in preventing and treating psychiatric sequelae and mental disorders resulting from stress stemming from the COVID-19 pandemic. Herein, we systematically summarise, analyse and discuss the therapeutic effects of salidroside in the prevention and treatment of psychiatric sequelae as well as its roles in preventing the progression of mental disorders, and fully clarify the potential of salidroside as a widely applicable agent for preventing mental disorders caused by stress; the mechanisms underlying the potential protective effects of salidroside are involved in the regulation of the oxidative stress, neuroinflammation, neural regeneration and cell apoptosis in the brain, the network homeostasis of neurotransmission, HPA axis and cholinergic system, and the improvement of synaptic plasticity. Notably, this review innovatively proposes that salidroside is a potential agent for treating stress-induced health issues during the COVID-19 pandemic and provides scientific evidence and a theoretical basis for the use of natural products to combat the current mental health crisis.

Targeting inflammation and oxidative stress for protection against ischemic brain injury in rats using cupressuflavone

Inflammatory responses and oxidative stress contribute to the pathogenesis of brain ischemia/reperfusion (IR) injury. Naturally occurring bioflavonoids possess antioxidant and anti-inflammatory properties. The phytochemicals of Juniperus sabina L., known as "Abhal" in Saudi Arabia, have been studied and cupressuflavone (CUP) has been isolated as the major bioflavonoid. This study aimed to investigate the neuroprotective potential of CUP in reducing brain IR damage in rats and to understand probable mechanisms. After 60 min of inducing cerebral ischemia by closing the left common carotid artery (CCA), blood flow was restored to allow reperfusion. The same surgical procedure was performed on sham-operated control rats, excluding cerebral IR. CUP or vehicle was given orally to rats for 3 days prior to ischemia induction and for a further 3 days following reperfusion. Based on the findings of this study, compared to the IR control group, CUP-administered group demonstrated reduced neurological deficits, improved motor coordination, balance, and locomotor activity. Additionally, brain homogenates of IR rats showed a decrease in malondialdehyde (MDA) level, an increase in reduced glutathione (GSH) content, and an increase in catalase (CAT) enzyme activity following CUP treatment. CUP suppressed neuro-inflammation via reducing serum inflammatory cytokine levels, particularly those of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) and enhancing the inflammatory cytokine levels, such as Nuclear factor kappa- B (NF-κB), TANK-binding kinase-1 (TBK1), and interferon beta (IFN-β) in brain tissues. Furthermore, CUP ameliorated the histological alterations in the brain tissues of IR rats. CUP significantly suppressed caspase-3 expression and downregulated the Toll-like receptor 4 (TLR4)/NF-κB signaling pathway as a result of suppressing High mobility group box 1 (HMGB1). To our knowledge, this is the first study to document the neuroprotective properties of CUP. Thus, the study findings revealed that CUP ameliorates IR-induced cerebral injury possibly by enhancing brain antioxidant contents, reducing serum inflammatory cytokine levels, potentiating the brain contents of TBK1 and IFN-β and suppressing the HMGB1/TLR-4 signaling pathway. Hence, CUP may serve as a potential preventive and therapeutic alternative for cerebral stroke.

Escin avoids hemorrhagic transformation in ischemic stroke by protecting BBB through the AMPK/Cav-1/MMP-9 pathway

BACKGROUND

Hemorrhagic transformation (HT) seriously affects the clinical application of recombinant tissue plasminogen activator (rt-PA). The main strategy for combating HT is to keep the blood-brain barrier (BBB) stable. Escin is the active ingredient of Aesculus hippocastanum and a natural mixture of triterpene saponins, and may play a part in mitigation of HT.

PURPOSE

This study sought to investigate the effect of Escin in improving rt-PA-induced HT, explore possible mechanisms, and provide new ideas for the treatment of clinical HT.

STUDY DESIGN AND METHODS

In in vivo experiments, transient middle cerebral artery occlusion (tMCAO) was undertaken in 6-week-old and 12-month-old mice, and rt-PA was administered to induce HT injury. The inhibitory effect of Escin on HT and its protective effect on neurobehavior, the BBB, and cerebrovascular endothelial cells was determined. In in vitro experiments, bEnd.3 cells were injured by oxygen-glucose deprivation/reperfusion (OGD/R) and rt-PA. The protective effect of Escin was measured by the CCK8 assay, release of lactate dehydrogenase (LDH), and expression of tight junction (TJ) proteins. In mechanistic studies, the effect of Escin on the adenosine monophosphate-activated kinase / caveolin-1 / matrix metalloprotease-9 (AMPK/Cav-1/MMP-9) pathway was investigated by employing AMPK inhibitor and Cav-1 siRNA.

RESULTS

In mice suffering from ischemia, rt-PA caused HT as well as damage to the BBB and cerebrovascular endothelial cells. Escin reduced the infarct volume, cerebral hemorrhage, improved neurobehavioral deficits, and maintained BBB integrity in rt-PA-treated tMCAO mice while attenuating bEnd.3 cells damage caused by rt-PA and OGD/R injury. Under physiological and pathological conditions, Escin increased the expression of p-AMPK and Cav-1, leading to decreased expression of MMP-9, which further attenuated damage to cerebrovascular endothelial cells, and these effects were verified with AMPK inhibitor and Cav-1 siRNA.

CONCLUSION

We revealed important details of how Escin protects cerebrovascular endothelial cells from HT, these effects were associated with the AMPK/Cav-1/MMP-9 pathway. This study provides experimental foundation for the development of new drugs to mitigate rt-PA-induced HT and the discovery of new clinical application for Escin.

Targeted Energy Metabolomics Combined with Spatial Metabolomics Study on the Efficacy of Guhong Injection Against Cerebral Ischemia Reperfusion

Optimizing the metabolic phenotype to improve cerebral function is critical for treatment of cerebral ischemia-reperfusion (I/R) injury. Guhong injection (GHI), which comprised safflower extract and aceglutamide, is widely prescribed in Chinese medicine for the treatment of cerebrovascular diseases. In this study, a combination of LC-QQQ-MS and MALDI-MSI were utilized to explore tissue-specific metabolic alterations in the brain of I/R, as well as to evaluate the therapeutic effect of GHI. Pharmacological evaluation demonstrated that GHI can significantly improve infarction rate, neurological deficit, cerebral blood flow, and neuronal damage in I/R rats. Based on LC-QQQ-MS, 23 energy metabolites were found to be significantly altered in the I/R group compared to the sham group (P < 0.05). After GHI treatment, 12 metabolites, including G6P, TPP, NAD, citrate, succinate, malate, ATP, GTP, GDP, ADP, NADP, and FMN showed a significant tendency of returning to baseline values (P < 0.05). Based on MALDI-MSI, 4 metabolites in glycolysis and TCA, 4 metabolites in nucleic acid metabolism, 4 amino acid metabolites, and 6 metabolites were discovered and compared between the different groups in the four special regions of cortex, hippocampus, hypothalamus, and striatum. Parts of these were found to have significant changes after I/R in the special brain region, and were regulated by GHI. The study provides comprehensive and detailed information for specific metabolic reprogramming of brain tissue in rats with I/R, and the therapeutic effect of GHI. Schema describing the discovery strategies of integrated LC-MS and MALDI-MSI to identify cerebral ischemia reperfusion metabolic reprogramming and GHI therapeutic effects.

Pterostilbene alleviated cerebral ischemia/reperfusion-induced blood-brain barrier dysfunction via inhibiting early endothelial cytoskeleton reorganization and late basement membrane degradation

Pterostilbene, an important analogue of the star molecule resveratrol and a novel compound naturally occurring in blueberries and grapes, exerts a significant neuroprotective effect on cerebral ischemia/reperfusion (I/R), but its mechanism is still unclear. This study aimed to follow the molecular mechanisms behind the potential protective effect of pterostilbene against I/R induced injury. For fulfilment of our aim, we investigated the protective effects of pterostilbene on I/R injury caused by middle cerebral artery occlusion (MCAO) in vivo and oxygen-glucose deprivation (OGD) in vitro. Machine learning models and molecular docking were used for target exploration and validated by western blotting. Pterostilbene significantly reduced the cerebral infarction volume, improved neurological deficits, increased cerebral microcirculation and improved blood-brain barrier (BBB) leakage. Machine learning models confirmed that the stroke target MMP-9 bound to pterostilbene, and molecular docking demonstrated the strong binding activity. We further found that pterostilbene could depolymerize stress fibers and maintain the cytoskeleton by effectively increasing the expression of the non-phosphorylated actin depolymerizing factor (ADF) in the early stage of I/R. In the late stage of I/R, pterostilbene could activate the Wnt pathway and inhibit the expression of MMP-9 to decrease the degradation of the extracellular basement membrane (BM) and increase the expression of junction proteins. In this study, we explored the protective mechanisms of pterostilbene in terms of both endothelial cytoskeleton and extracellular matrix. The early and late protective effects jointly maintain BBB stability and attenuate I/R injury, showing its potential to be a promising drug candidate for the treatment of ischemic stroke.

Vasoprotective Effects of Hyperoside against Cerebral Ischemia/Reperfusion Injury in Rats: Activation of Large-Conductance Ca2+-Activated K+ Channels

Hyperoside (Hyp), a kind of Chinese herbal medicine, exerts multiple therapeutic effects on many diseases. However, the role and mechanisms of Hyp in vascular pathophysiology in ischemic stroke need to be further established. The study aimed to investigate the role of (large-conductance Ca2+-activated K+) BK channels on the vasoprotection of Hyp against cerebral ischemia and reperfusion (I/R) injury in rats. The concentration gradient of Hyp was pretreated in both the middle cerebral artery occlusion and reperfusion model and oxygen-glucose deprivation/reoxygenation (OGD/R) model of primary vascular smooth muscle cells (VSMCs) in rats. A series of indicators were detected, including neurological deficit score, infarct volume, malondialdehyde (MDA), superoxide dismutase (SOD), cerebral blood flow (CBF), cell viability, membrane potential, and BK channels α- and β1-subunits expression. The results showed that Hyp significantly reduced infarct volume and ameliorated neurological dysfunction in I/R-injured rats. Besides, the effects of I/R-induced reduction of BK channels α- and β1-subunits expression were significantly reversed by Hyp in endothelial-denudated cerebral basilar arteries. Furthermore, the protective effect against I/R-induced increases of MDA and reduction of SOD as well as CBF induced by Hyp was significantly reversed by iberiotoxin (IbTX). In OGD/R-injured VSMCs, downregulated cellular viability and BK channels β1-subunits expression were remarkably reversed by Hyp. However, neither OGD/R nor Hyp affected BK channels α-subunits expression, and Hyp failed to induced hyperpolarization of VSMCs. Moreover, the protective effect against OGD/R-induced reduction of cell viability and SOD level and increases of MDA production induced by Hyp was significantly reversed by IbTX in VSMCs. The study indicates that Hyp has the therapeutic potential to improve vascular outcomes, and the mechanism is associated with suppressing oxidative stress and improving CBF through upregulating BK channels.

Jasminoidin and ursodeoxycholic acid exert synergistic effect against cerebral ischemia-reperfusion injury via Dectin-1-induced NF-κB activation pathway

BACKGROUND

Jasminoidin (JA) and ursodeoxycholic acid (UA) were shown to act synergistically against ischemic stroke (IS) in our previous studies.

PURPOSE

To investigate the holistic synergistic mechanism of JA and UA on cerebral ischemia.

METHODS

Middle cerebral artery obstruction reperfusion (MCAO/R) mice were used to evaluate the efficacy of JA, UA, and JA combined with UA (JU) using neurological function testing and infarct volume examination. High-throughput RNA-seq combined with computational prediction and function-integrated analysis was conducted to gain insight into the comprehensive mechanism of synergy. The core mechanism was validated using western blotting.

RESULTS

JA and UA synergistically reduced cerebral infarct volume and alleviated neurological deficits and pathological changes in MCAO/R mice. A total of 1437, 396, 1080, and 987 differentially expressed genes were identified in the vehicle, JA, UA, and JU groups, respectively. A strong synergistic effect between JA and UA was predicted using chemical similarity analysis, target profile comparison, and semantic similarity analysis. As the 'long-tail' drugs, the top 20 gene ontology (GO) biological processes of JA, UA, and JU groups primarily reflected inflammatory response and regulation of cytokine production, with specific GO terms of JU revealing enhanced regulation on immune response and tumor necrosis factor superfamily cytokine production. Comparably, the Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling of common targets of JA, UA, and JU focused on extracellular matrix organization and signaling by interleukins, immune system, phagosomes, and lysosomes, which interlock and interweave to produce the synergistic effects of JU. The characteristic signaling pathway identified for JU highlighted the crosstalk between autophagy activation and inflammatory pathways, especially the Dectin-1-induced NF-κB activation pathway, which was validated by in vivo experiments.

CONCLUSIONS

JA and UA can synergistically protect cerebral ischemia-reperfusion injury by attenuating Dectin-1-induced NF-κB activation. The strategy integrating high throughput data with computational models enables ever-finer mapping of 'long-tail' drugs to dynamic variations in condition-specific omics to clarify synergistic mechanisms.

Protection of Oxygen Glucose Deprivation-Induced Human Brain Vascular Pericyte Injury: Beneficial Effects of Bellidifolin in Cellular Pyroptosis

Pericytes play critical roles in the maintenance of brain vascular homeostasis. However, very little is currently known about how pericytes regulate ischemic stroke-induced brain injury. Inflammation is a key event in the pathobiology of stroke, in which the nod-like receptor protein-3 (NLRP3) inflammasome is involved in, triggering sterile inflammatory responses and pyroptosis. In the current study, an immortalized cell line derived from human brain vascular pericytes (HBVPs) was constructed, and it showed that HBVPs challenged with oxygen glucose deprivation (OGD) displays pronounced cellular excretion of LDH, IL-1β, IL-18 and increased PI positive staining. Mechanistically, upon OGD treatment, NLRP3 forms an inflammasome with its adaptor protein apoptosis-associated speck-like protein, containing a caspase recruitment domain (ASC) and caspase-1, manifested as much more co-stainings of NLRP3, ASC and Caspase-1 in HBVPs, accompanied by the increased protein levels of NLRP3, ASC, caspase-1 as well as the pyroptosis-associated protein gasdermin D (GSDMD). Intriguingly, GSDMD-N shuttled to the mitochondrial membrane triggered by OGD exposure, which promoted massive mitochondria-derived ROS generation. Importantly, the invention value of the specific targets was evaluated by treatment with bellidifolin, a kind of ketone compound derived from Swertia chirayita in traditional Tibetan medicine. It showed that bellidifolin exerts beneficial effects and attenuates the formation of NLRP3/ASC/Caspase-1 complex, thereby impeding GSDMD-N shuttling and resultant ROS generation, protecting against OGD-induced HBVPs pyroptosis. Overall, these findings unravel the potential mechanisms of pericyte injury induced by OGD and indicate that bellidifolin may exert its beneficial effects on pyroptosis, thus providing new therapeutic insights into stroke.

Neuroprotective Peptides and New Strategies for Ischemic Stroke Drug Discoveries

Ischemic stroke continues to be one of the leading causes of death and disability in the adult population worldwide. The currently used pharmacological methods for the treatment of ischemic stroke are not effective enough and require the search for new tools and approaches to identify therapeutic targets and potential neuroprotectors. Today, in the development of neuroprotective drugs for the treatment of stroke, special attention is paid to peptides. Namely, peptide action is aimed at blocking the cascade of pathological processes caused by a decrease in blood flow to the brain tissues. Different groups of peptides have therapeutic potential in ischemia. Among them are small interfering peptides that block protein-protein interactions, cationic arginine-rich peptides with a combination of various neuroprotective properties, shuttle peptides that ensure the permeability of neuroprotectors through the blood-brain barrier, and synthetic peptides that mimic natural regulatory peptides and hormones. In this review, we consider the latest achievements and trends in the development of new biologically active peptides, as well as the role of transcriptomic analysis in identifying the molecular mechanisms of action of potential drugs aimed at the treatment of ischemic stroke.

Multi-pathway neuroprotective effects of a novel salidroside derivative SHPL-49 against acute cerebral ischemic injury

SHPL-49 ((2R,3S,4S,5R,6R)-2-(hydroxymethyl)-6-(4-(4-methoxyphenyl) butoxy) tetrahydro-2H-pyran-3,4,5-triol) is a novel glycoside derivative obtained from structural modification of salidroside, which is isolated from the medicinal plant Rhodiola rosea L. SHPL-49 was administered to rats with permanent middle cerebral artery occlusion (pMCAO) for 5 days, and it was found that SHPL-49 could alleviate the cerebral infarct volume and reduce the neurological deficit score. Moreover, the effective time window of SHPL-49 in the pMCAO model was from 0.5 to 8 h after embolization. In addition, the result of immunohistochemistry showed that SHPL-49 could increase the number of neurons in the brain tissue and reduce the occurrence of apoptosis. Morris water maze and Rota-rod experiments showed that SHPL-49 could improve neurological deficits, repair neurocognitive and motor dysfunction, and enhance learning and memory ability in the pMCAO model after 14 days of SHPL-49 treatment. Further in vitro experiments showed that SHPL-49 significantly reduced the calcium overload of PC-12 cells and the production of reactive oxygen species (ROS) induced by oxygen and glucose deprivation (OGD), and increased the levels of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), decreased the production of malondialdehyde (MDA). Furthermore, SHPL-49 could reduce cell apoptosis by increasing protein expression ratio of anti-apoptotic factor Bcl-2 to pro-apoptotic factor Bax in vitro. SHPL-49 also regulated the expression of Bcl-2 and Bax in ischemic brain tissue, and even inhibited the caspase cascade of pro-apoptotic proteins Cleaved-caspase 9 and Cleaved-caspase 3. Taken together, SHPL-49 exhibited neuroprotective effects against cerebral ischemic injury through multiple pathways, such as alleviating calcium overload, reducing oxidative stress damage, and inhibiting apoptosis.

Therapeutic potential of stem cell extracellular vesicles for ischemic stroke in preclinical rodent models: a meta-analysis

BACKGROUND

Extracellular vesicles derived from stem cells (SC-EVs) have been proposed as a novel therapy for ischemic stroke. However, their effects remain incompletely understood. Therefore, we conducted this meta-analysis to systematically review the efficacy of SC-EVs on ischemic stroke in preclinical rodent models.

METHODS

Using PubMed, EMBASE, and the Web of Science, we searched through studies published up to August 2021 that investigated the treatment effects of SC-EVs in a rodent ischemic stroke model. Infarct volume was the primary outcome. Neurological severity scores (mNSS) were the secondary outcome. The standard mean difference (SMD) and the confidence interval (CI) were calculated using a random-effects model. R and Stata 15.1 were used to conduct the meta-analysis.

RESULTS

Twenty-one studies published from 2015 to 2021 met the inclusion criteria. We also found that SCs-EVs reduced infarct volume by an SMD of - 2.05 (95% CI - 2.70, - 1.40; P < 0.001). Meanwhile, our results revealed an overall positive effect of SCs-derived EVs on the mNSS with an SMD of - 1.42 (95% CI - 1.75, - 1.08; P < 0.001). Significant heterogeneity among studies was observed. Further stratified and sensitivity analyses did not identify the source of heterogeneity.

CONCLUSION

The present meta-analysis confirmed that SC-EV therapy could improve neuron function and reduce infarct volume in a preclinical rodent ischemic stroke model, providing helpful clues for human clinical trials on SC-EVs.

Pushen capsule treatment promotes functional recovery after ischemic stroke

BACKGROUND

As a leading cause of long-term disability, ischemic stroke urgently needs further research and drug development. Pushen capsule (Pushen) has been commonly applied in clinical treatment for relieving headaches, dizziness, and numbness. However, the effects of Pushen on ischemic stroke have not been revealed yet.

PURPOSE

To assess the efficiency of Pushen in ischemic stroke and identify its potential therapeutic targets and active ingredients for treating ischemic stroke.

STUDY DESIGN AND METHODS

Behavioural experiments, Triphenyltetrazolium chloride (TTC) staining, Magnetic resonance imaging (MRI), and immunofluorescence staining were performed to examine the efficiency of Pushen in stroke model mice. The potential mechanism and active ingredients of Pushen were assessed by transcriptome, 16S rDNA sequencing, metabonomics, and network pharmacology. Finally, the targets were validated by RT-PCR, chromatin immunoprecipitation (ChIP), ELISA, and molecular docking methods.

RESULTS

Pushen had several effects on stroke model mice, including reducing the infarct volume, improving the blood‒brain barrier (BBB), and promoting functional restoration. Furthermore, the network pharmacology, LC-MS/MS, and molecular docking results revealed that tricin, quercetin, luteolin, kaempferol, and physcion were identified as the key active ingredients in Pushen that treated ischemic stroke. Mechanistically, these key ingredients could bind with the transcription factor c-Myc and thereby regulate the expression of Adora2a, Drd2, and Ppp1r1b, which are enriched in the cAMP signaling pathway. Additionally, Pushen improved the gut microbiota dysbiosis and reduced inosine levels in feces and serum, thereby reducing Adora2a expression in the brain.

CONCLUSIONS

Our study confirmed that Pushen was effective for treating ischemic stroke and has promising clinical applications.

Regulation of microglia related neuroinflammation contributes to the protective effect of Gelsevirine on ischemic stroke

Stroke, especially ischemic stroke, is an important cause of neurological morbidity and mortality worldwide. Growing evidence suggests that the immune system plays an intricate function in the pathophysiology of stroke. Gelsevirine (Gs), an alkaloid from Gelsemium elegans, has been proven to decrease inflammation and neuralgia in osteoarthritis previously, but its role in stroke is unknown. In this study, the middle cerebral artery occlusion (MCAO) mice model was used to evaluate the protective effect of Gs on stroke, and the administration of Gs significantly improved infarct volume, Bederson score, neurobiological function, apoptosis of neurons, and inflammation state in vivo. According to the data in vivo and the conditioned medium (CM) stimulated model in vitro, the beneficial effect of Gs came from the downregulation of the over-activity of microglia, such as the generation of inflammatory factors, dysfunction of mitochondria, production of ROS and so on. By RNA-seq analysis and Western-blot analysis, the JAK-STAT signal pathway plays a critical role in the anti-inflammatory effect of Gs. According to the results of molecular docking, inhibition assay, and thermal shift assay, the binding of Gs on JAK2 inhibited the activity of JAK2 which inhibited the over-activity of JAK2 and downregulated the phosphorylation of STAT3. Over-expression of a gain-of-function STAT3 mutation (K392R) abolished the beneficial effects of Gs. So, the downregulation of JAK2-STAT3 signaling pathway by Gs contributed to its anti-inflammatory effect on microglia in stroke. Our study revealed that Gs was benefit to stroke treatment by decreasing neuroinflammation in stroke as a potential drug candidate regulating the JAK2-STAT3 signal pathway.

Pharmacological properties and mechanisms of Notoginsenoside R1 in ischemia-reperfusion injury

Panax notoginseng is an ancient Chinese medicinal plant that has great clinical value in regulating cardiovascular disease in China. As a single component of panax notoginosides, notoginsenoside R1 (NGR1) belongs to the panaxatriol group. Many reports have demonstrated that NGR1 exerts multiple pharmacological effects in ischemic stroke, myocardial infarction, acute renal injury, and intestinal injury. Here, we outline the available reports on the pharmacological effects of NGR1 in ischemia-reperfusion (I/R) injury. We also discuss the chemistry, composition and molecular mechanism underlying the anti-I/R injury effects of NGR1. NGR1 had significant effects on reducing cerebral infarct size and neurological deficits in cerebral I/R injury, ameliorating the impaired mitochondrial morphology in myocardial I/R injury, decreasing kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin in renal I/R injury and attenuating jejunal mucosal epithelium injury in intestinal I/R injury. The various organ anti-I/R injury effects of NGR1 are mainly through the suppression of oxidative stress, apoptosis, inflammation, endoplasmic reticulum stress and promotion of angiogenesis and neurogenesis. These findings provide a reference basis for future research of NGR1 on I/R injury.

Remote ischemic conditioning attenuates blood-brain barrier disruption after recombinant tissue plasminogen activator treatment via reducing PDGF-CC

Treatment of acute ischemic stroke with the recombinant tissue plasminogen activator (rtPA) is associated with increased blood-brain barrier (BBB) disruption and hemorrhagic transformation. Remote ischemic conditioning (RIC) has demonstrated neuroprotective effects against acute ischemic stroke. However, whether and how RIC regulates rtPA-associated BBB disruption remains unclear. Here, a rodent model of thromboembolic stroke followed by rtPA thrombolysis at different time points was performed with or without RIC. Brain infarction, neurological outcomes, BBB permeability, and intracerebral hemorrhage were assessed. The platelet-derived growth factor CC (PDGF-CC)/PDGFRα pathway in the brain tissue, PDGF-CC levels in the skeletal muscle and peripheral blood were also measured. Furthermore, impact of RIC on serum PDGF-CC levels were measured in healthy subjects and AIS patients. Our results showed that RIC substantially reduced BBB injury, intracerebral hemorrhage, cerebral infarction, and neurological deficits after stroke, even when rtPA was administrated in a delayed therapeutic time window. Mechanistically, RIC significantly decreased PDGFRα activation in ischemic brain tissue and reduced blood PDGF-CC levels, which partially resulted from PDGF-CC reduction in the skeletal muscle of RIC-applied hindlimbs and platelets. Intravenous or intraventricular recombinant PDGF-CC supplementation abolished RIC protective effects on BBB integrity. Moreover, similar changes of PDGF-CC in serum by RIC were also observed in healthy humans and acute ischemic stroke patients. Together, our study demonstrates that RIC can attenuate rtPA-aggravated BBB disruption after ischemic stroke via reducing the PDGF-CC/PDGFRα pathway and thus supports RIC as a potential approach for BBB disruption prevention or treatment following thrombolysis.

Advances in Antibody-Based Therapeutics for Cerebral Ischemia

Cerebral ischemia is an acute disorder characterized by an abrupt reduction in blood flow that results in immediate deprivation of both glucose and oxygen. The main types of cerebral ischemia are ischemic and hemorrhagic stroke. When a stroke occurs, several signaling pathways are activated, comprising necrosis, apoptosis, and autophagy as well as glial activation and white matter injury, which leads to neuronal cell death. Current treatments for strokes include challenging mechanical thrombectomy or tissue plasminogen activator, which increase the danger of cerebral bleeding, brain edema, and cerebral damage, limiting their usage in clinical settings. Monoclonal antibody therapy has proven to be effective and safe in the treatment of a variety of neurological disorders. In contrast, the evidence for stroke therapy is minimal. Recently, Clone MTS510 antibody targeting toll-like receptor-4 (TLR4) protein, ASC06-IgG1 antibody targeting acid sensing ion channel-1a (ASIC1a) protein, Anti-GluN1 antibodies targeting N-methyl-D-aspartate (NMDA) receptor associated calcium influx, GSK249320 antibody targeting myelin-associated glycoprotein (MAG), anti-High Mobility Group Box-1 antibody targeting high mobility group box-1 (HMGB1) are currently under clinical trials for cerebral ischemia treatment. In this article, we review the current antibody-based pharmaceuticals for neurological diseases, the use of antibody drugs in stroke, strategies to improve the efficacy of antibody therapeutics in cerebral ischemia, and the recent advancement of antibody drugs in clinical practice. Overall, we highlight the need of enhancing blood-brain barrier (BBB) penetration for the improvement of antibody-based therapeutics in the brain, which could greatly enhance the antibody medications for cerebral ischemia in clinical practice.

Folium Ginkgo extract and tetramethylpyrazine sodium chloride injection (Xingxiong injection) protects against focal cerebral ischaemia/reperfusion injury via activating the Akt/Nrf2 pathway and inhibiting NLRP3 inflammasome activation

CONTEXT

Folium Ginkgo extract and tetramethylpyrazine sodium chloride injection (Xingxiong injection) is a compound preparation commonly used for treating cerebral ischaemia/reperfusion injury in ischaemic stroke in China. However, its potential mechanisms on ischaemic stroke remain unknown.

OBJECTIVE

This study explores the potential mechanisms of Xingxiong injection in vivo or in vitro.

MATERIALS AND METHODS

Sprague-Dawley (SD) rats were randomly assigned to five groups: the sham (normal saline), the model (normal saline) and the Xingxiong injection groups (12.5, 25 or 50 mL/kg). The rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) followed by reperfusion for 14 d. Xingxiong injection was administered via intraperitoneal (i.p.) injection immediately after ischaemia induction for 14 d. Afterwards, rats were sacrificed at 14 d induced by administration of Xingxiong injection.

RESULTS

Xingxiong injection significantly reduces infarct volume (23%) and neurological deficit scores (93%) compared with the MCAO/R group. Additionally, Xingxiong injection inhibits the loss in mitochondrial membrane potential (43%) and reduces caspase-3 level (44%), decreases NOX (41%), protein carbonyl (29%), 4-HNE (40%) and 8-OhdG (41%) levels, inhibits the expression of inflammatory factors, such as TNF-α (26%), IL-1β (34%), IL-6 (39%), MCP-1 (36%), CD11a (41%) and ICAM-1 (43%). Moreover, Xingxiong injection can increase p-Akt/Akt (35%) and Nrf2 (47%) protein expression and inhibit NLRP3 (42%) protein expression.

CONCLUSIONS

Xingxiong injection prevents cerebral ischaemia/reperfusion injury via activating the Akt/Nrf2 pathway and inhibiting NLRP3 inflammasome. These findings provide experimental evidence for clinical use of drugs in the treatment of ischaemic stroke.

Exploring the potential mechanism of Fritiliariae Irrhosae Bulbus on ischemic stroke based on network pharmacology and experimental validation

Objective: To study the potential targets and molecular mechanisms of Fritiliariae Irrhosae Bulbus (FIB) in the treatment of ischemic strokes based on a network pharmacology strategy, with a combination of molecular docking and animal experiments.

Methods: The active components and targets of FIB were screened by TCMSP database and TCMIP database, and the related targets of ischemic strokes were screened by GeneCards, OMIM, CTD, and DrugBank, then the intersection targets of the two were taken. The protein interaction network was constructed by STRING, the PPI network diagram was drawn by using Cytoscape software, and the key targets of FIB treatment of ischemic strokes were analyzed by MCODE. The DAVID database was used for GO and KEGG enrichment analysis, and the potential pathway of FIB against ischemic strokes was obtained. Molecular docking was performed by using AutoDock Tools 1.5.6 software. Finally, a mouse model of ischemic stroke was established, and the results of network pharmacology were verified by in vivo experiments. Realtime Polymerase Chain Reaction was used to detect the expression levels of relevant mRNAs in the mouse brain tissue. Western blot was used to detect the expression levels of related proteins in the mouse brain tissue.

Results: 13 kinds of active components of FIB were screened, 31 targets were found in the intersection of FIB and ischemic strokes, 10 key targets were obtained by MCODE analysis, 236 biological processes were involved in GO enrichment analysis, and key targets of KEGG enrichment analysis were mainly concentrated in Neuroactive light receptor interaction, Calcium signaling pathway, Cholinergic synapse, Hepatitis B, Apoptosis—multiple specifications, Pathways in cancer and other significantly related pathways. There was good binding activity between the screened main active components and target proteins when molecular docking was performed. Animal experiments showed that the infarct volume of brain tissue in the FIB treatment group was considerably reduced. RT-qPCR and the results of Western Blot showed that FIB could inhibit the expression of active-Caspase3, HSP90AA1, phosphorylated C-JUN, and COX2.

Conclusion: Based on network pharmacology, the effect of FIB in the treatment of ischemic strokes was discussed through the multi-component-multi-target-multi-pathway. The therapeutic effect and potential mechanisms of FIB on ischemic strokes were preliminarily explored, which provided a ground work for further researches on the pharmacodynamic material basis, mechanism of action and clinical application.

Tong-Qiao-Huo-Xue decoction activates PI3K/Akt/mTOR pathway to reduce BMECs autophagy after cerebral ischemia/reperfusion injury

ETHNOPHARMACOLOGICAL RELEVANCE

Tong-Qiao-Huo-Xue Decoction (TQHXD) is a traditional classic Chinese Medicinal Formula (CMF) used for clinical treatment of ischemic stroke. TQHXD leads to improvement in the symptoms of the acute period of cerebral infarction and recovery period after stroke. Our previous studies also showed that TQHXD produced a significant protective effect on the brain after cerebral ischemia-reperfusion (I/R) injury. It is reported that autophagy is closely related to ischemic brain injury; however, the functional contribution of TQHXD to brain microvascular endothelial cell (BMEC) autophagy and its underlying mechanism remains unclear.

AIM OF THE STUDY

The purpose of this study was to investigate the effects and mechanism of TQHXD in inhibiting cerebral ischemia-induced endothelial autophagy.

MATERIALS AND METHODS

The high-performance liquid chromatography (HPLC) fingerprint of the chemical constituents from TQHXD was established for the quality control, and the Longa method was used to evaluate the efficacy of TQHXD in rats with middle cerebral artery occlusion (MCAO). The expression of LC3 was determined by immunofluorescence double staining. To evaluate the protective effects of TQHXD-containing cerebrospinal fluid (CSF) on BMECs injured by oxygen-glucose deprivation and reperfusion, cell survival rate was determined using the CCK-8 assay and cell apoptosis was determined by fluorescein isothiocyanate (FITC)-Annexin V/PI. Autophagy was detected using transmission electron microscopy.

RESULTS

The results showed that TQHXD-CSF significantly ameliorated oxygen-glucose deprivation/reperfusion (OGD/R)-induced injury in BMECs. Confocal microscopy and Western blot results showed that TQHXD-CSF reduced autophagy-related protein expression and autophagosome number. The results of the western blotting indicated that TQHXD-CSF caused a marked increase in the phosphorylation of protein kinase B and phosphoinsotide-3 kinase (Akt/p-Akt and PI3K/p-PI3K, respectively) and their expression levels were down-regulated after treatment with pathway inhibitor, ZSTK474. Furthermore, in a MCAO model in rats, TQHXD markedly increased p-PI3K, p-Akt and p-mTOR, whereas the autophagy related proteins decreased.

CONCLUSIONS

Taken together, these findings demonstrate that TQHXD protects against ischemic insult by inhibiting autophagy through the regulation of the PI3K/Akt/mammalian target of rapamycin (mTOR) pathway and that TQHXD may have therapeutic value for protecting BMECs from cerebral ischemia.

Ras-related protein Rab-20 inhibition alleviates cerebral ischemia/reperfusion injury by inhibiting mitochondrial fission and dysfunction

Ras-related protein Rab-20 (Rab20) is induced in hypoxia and contributes to hypoxia-induced apoptosis. However, the role and mechanism of Rab20 in cerebral ischemia/reperfusion (I/R) injury need to be elucidated. We established a cerebral I/R injury model in the mice and an oxygen-glucose deprivation/reoxygenation (OGD/R) model in HT22 cells to determine the effects of Rab20 in cerebral I/R injury. Rab20 expression was upregulated in mice after I/R and in HT22 cells after OGD/R. Upregulated Rab20 was mainly located in neurons. Rab20 inhibition significantly alleviated brain infarct volume, neurological deficits, and neuronal apoptosis in mice after I/R. Moreover, Rab20 knockdown significantly ameliorated the OGD/R-induced inhibition of cell viability and apoptotic cell death in HT22 cells. Rab20 knockdown significantly alleviated OGD/R-induced mitochondrial fission by repressing mitochondrial dynamin-related protein 1 (Drp-1) recruitment and increasing Drp-1 (Ser637) phosphorylation and ameliorated mitochondrial dysfunction by reducing the mitochondrial reactive oxygen species (ROS) and cellular calcium accumulation and increasing the mitochondrial membrane potential. In addition, Rab20 knockdown significantly alleviated cytochrome c release from the mitochondria into the cytosol in HT22 cells after OGD/R. Rab20 contributes to cerebral I/R injury by regulating mitochondria-associated apoptosis pathways. Targeting Rab20 may be an attractive strategy for the treatment of cerebral I/R injury.

Investigation into the potential mechanism and molecular targets of Fufang Xueshuantong capsule for the treatment of ischemic stroke based on network pharmacology and molecular docking

Fufang Xueshuantong (FFXST) capsule is a traditional Chinese medicine (TCM) preparation used to activate blood circulation, resolve stasis, benefit qi, and nourish yin in clinical practice. However, its potential mechanism and molecular targets after ischemic stroke (IS) have not been investigated. The aim of this research was to investigate the molecular mechanisms of FFXST in the treatment of IS based on network pharmacology and molecular docking. We used the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP) to collect candidate compounds of four herbs in FFXST; disease-related differential genes were screened using the Gene Expression Omnibus (GEO) database, and a compound–disease network was created using Cytoscape 3.8.2 software. The topological analysis of the protein–protein interaction (PPI) network was then created to determine the candidate targets of FFXST against IS. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted using the clusterProfiler package in R. The gene–pathway network of FFXST against IS was created to obtain the key target genes. Molecular docking was used to validate the core targets using AutoDock Vina 1.1.2. A total of 455 candidate compounds of FFXST and 18,544 disease-related differential genes were screened. Among them, FFXST targets for IS treatment had 67 active compounds and 10 targets in the PPI network related to STAT1, STAT3, and HIF1A. The biological processes of GO analysis included the regulation of reactive oxygen species metabolic process, cellular response to chemical stress, regulation of angiogenesis, regulation of vasculature development, positive regulation of cytokine production, and response to oxidative stress. The KEGG enrichment analysis showed that Kaposi sarcoma-associated herpesvirus infection, microRNAs in the cancer signaling pathway, Th17 cell differentiation, and HIF-1 signaling pathway were significantly enriched. The network pharmacology outcomes were further verified by molecular docking. We demonstrated that FFXST protection against IS may relate to the regulation of oxidative stress, immune inflammatory response, and angiogenesis through the relevant signaling pathways. Our study systematically illustrated the application of network pharmacology and molecular docking in evaluating characteristics of multi-component, multi-target, and multi-pathway of FFXST for IS.

Group III metabotropic glutamate receptors as promising targets for neuroprotective therapy: Particular emphasis on the role of mGlu4 and mGlu7 receptors

There is still no effective treatment for central nervous system (CNS) pathologies, including cerebral ischemia, neurotrauma, and neurodegenerative diseases in which the Glu/GABA balance is disturbed with associated excitotoxicity. It is thus important to search for new efficacious therapeutic strategies. Preclinical studies on the role of metabotropic glutamate receptors (mGluRs) in neuroprotection conducted over the years show that these receptors may have therapeutic potential in these CNS disorders. However, clinical trials, especially for treating Parkinson's disease, have been unsatisfactory. This review focuses on the specific role of group III mGluRs in neuroprotection in experimental in vitro and in vivo models of excitotoxicity/neurotoxicity using neurotoxins as well as ischemia, traumatic brain injury, and neurodegenerative diseases such as Parkinson's disease, Alzheimer's diseases, and multiple sclerosis. The review highlights recent preclinical studies in which group III mGluR ligands (especially those acting at mGluR4 or mGluR7) were administered after damage, thus emphasizing the importance of the therapeutic time window in the treatment of ischemic stroke and traumatic brain injury. From a clinical standpoint, the review also highlights studies using group III mGluR agonists with favorable neuroprotective efficacy (histological and functional) in experimental ischemic stroke, including healthy normotensive and-hypertensive rats. This review also summarizes possible mechanisms underlying the neuroprotective activity of the group III mGluR ligands, which may be helpful in developing more effective and safe therapeutic strategies. Therefore, to fully assess the role of these receptors in neuroprotection, it is necessary to uncover new selective ligands, primarily those stimulating mGlu4 and mGlu7 receptors.

Combination of panax ginseng and ginkgo biloba extracts attenuate cerebral ischemia injury with modulation of NLRP3 inflammasome and CAMK4/CREB pathway

Stroke is a major cause of death and disability throughout the world. A combination of Panax Ginseng and Ginkgo biloba extracts (CGGE) is an effective treatment for nervous system diseases, but the neuroprotective mechanism underlying CGGE remains unclear. Both network analysis and experimental research were employed to explore the potential mechanism of CGGE in treating ischemic stroke (IS). Network analysis identified a total number of 133 potential targets for 34 active ingredients and 239 IS-related targets. What’s more, several processes that might involve the regulation of CGGE against IS were identified, including long-term potentiation, cAMP signaling pathway, neurotrophin signaling pathway, and Nod-like receptor signaling pathway. Our studies in animal models suggested that CGGE could reduce inflammatory response by inhibiting the activity of Nod-like receptor, pyrin containing 3 (NLRP3) inflammasome, and maintain the balance of glutamate (Glu)/gamma-aminobutyric acid (GABA) via activating calmodulin-dependent protein kinase type Ⅳ (CAMK4)/cyclic AMP-responsive element-binding protein (CREB) pathway. These findings indicated the neuroprotective effects of CGGE, possibly improving neuroinflammation and excitotoxicity by regulating the NLRP3 inflammasome and CAMK4/CREB pathway.

Excitatory Synaptic Transmission in Ischemic Stroke: A New Outlet for Classical Neuroprotective Strategies

Stroke is one of the leading causes of death and disability in the world, of which ischemia accounts for the majority. There is growing evidence of changes in synaptic connections and neural network functions in the brain of stroke patients. Currently, the studies on these neurobiological alterations mainly focus on the principle of glutamate excitotoxicity, and the corresponding neuroprotective strategies are limited to blocking the overactivation of ionic glutamate receptors. Nevertheless, it is disappointing that these treatments often fail because of the unspecificity and serious side effects of the tested drugs in clinical trials. Thus, in the prevention and treatment of stroke, finding and developing new targets of neuroprotective intervention is still the focus and goal of research in this field. In this review, we focus on the whole processes of glutamatergic synaptic transmission and highlight the pathological changes underlying each link to help develop potential therapeutic strategies for ischemic brain damage. These strategies include: (1) controlling the synaptic or extra-synaptic release of glutamate, (2) selectively blocking the action of the glutamate receptor NMDAR subunit, (3) increasing glutamate metabolism, and reuptake in the brain and blood, and (4) regulating the glutamate system by GABA receptors and the microbiota–gut–brain axis. Based on these latest findings, it is expected to promote a substantial understanding of the complex glutamate signal transduction mechanism, thereby providing excellent neuroprotection research direction for human ischemic stroke (IS).

MeCP2 inhibits ischemic neuronal injury by enhancing methylation of the FOXO3a promoter to repress the SPRY2-ZEB1 axis

Methyl CpG binding protein 2 (MeCP2) is involved in nerve regeneration following ischemic stroke, but the related mechanism remains unclear. Here, we found low MeCP2 expression in hippocampal tissues. Using functional analysis, we demonstrated that MeCP2 accelerated FOXO3a methylation and subsequently inhibited its expression, thus repressing the apoptosis of neuronal cells. Mechanistically, FOXO3a could bind to the promoter region of SPRY2, consequently inducing its transcription and promoting the expression of the downstream target gene ZEB1. Altogether, our study revealed that overexpression of MeCP2 can protect mice against ischemic brain injury via disruption of the FOXO3a/SPRY2/ZEB1 signaling axis. Our results identify ectopic expression of MeCP2 as a therapeutic target in ischemic stroke.

Dexmedetomidine pretreatment alleviates cerebral ischemia/reperfusion injury by inhibiting neuroinflammation through the JAK2/STAT3 pathway

Dexmedetomidine (DEX) is known to provide neuroprotection against cerebral ischemia and reperfusion injury (CIRI), but the exact mechanisms remain unclear. This study was conducted to investigate whether DEX pretreatment conferred neuroprotection against CIRI by inhibiting neuroinflammation through the JAK2/STAT3 signaling pathway. Middle cerebral artery occlusion (MCAO) was performed to establish a cerebral ischemia/reperfusion (I/R) model. Specific-pathogen-free male Sprague-Dawley rats were randomly divided into Sham, I/R, DEX, DEX+IL-6, and AG490 (a selective inhibitor of JAK2) groups. The Longa score, TTC staining, and HE staining were used to evaluate brain damage. ELISA was used to exam levels of TNF-α. Western blotting was used to assess the levels of JAK2, phosphorylated-JAK2 (p-JAK2), STAT3, and phosphorylated-STAT3 (p-STAT3). Our results suggested that both pretreatment with DEX and AG490 decreased the Longa score and cerebral infarct areas following cerebral I/R. After treatment with IL-6, the effects of DEX on abrogating these pathological changes were reduced. HE staining revealed that I/R-induced neuronal pathological changes were attenuated by DEX application, consistent with the AG490 group. However, these effects of DEX were abolished by IL-6. Furthermore, TNF-α levels were significantly increased in the I/R group, accompanied by an increase in the levels of the p-JAK2 and p-STAT3. DEX and AG490 pretreatment down-regulated the expressions of TNF-α, p-JAK2, and p-STAT3. In contrast, the down-regulation of TNF-α, p-JAK2, and p-STAT3 induced by DEX was reversed by IL-6. Collectively, our results indicated that DEX pretreatment conferred neuroprotection against CIRI by inhibiting neuroinflammation via negatively regulating the JAK2/STAT3 signaling pathway.

Calenduloside E alleviates cerebral ischemia/reperfusion injury by preserving mitochondrial function

Calenduloside E (CE) isolated from Aralia elata (Miq.) Seem. is a natural triterpenoid saponin that can reportedly ameliorate myocardial ischemia/reperfusion injury. However, its potential roles and mechanism in cerebral ischemia/reperfusion injury are barely understood. In this study, we established an oxygen-glucose deprivation/reoxygenation (OGD/R) model in HT22 cells. We found that CE significantly attenuated the OGD/R-induced inhibition of cell viability and apoptotic cell death in HT22 cells. Moreover, CE treatment significantly ameliorated OGD/R-induced mitochondrial fission by inhibiting mitochondrial dynamin-related protein 1 (Drp1) recruitment and increasing Drp1 phosphorylation at Ser637. CE treatment significantly ameliorated OGD/R-induced mitochondrial dysfunction by increasing the mitochondrial membrane potential and reducing the mitochondrial ROS and cellular calcium accumulation. Moreover, CE treatment significantly inhibited the OGD/R-induced release of mitochondrial Cytochrome C and increase in Bax, Cleaved-caspase3 and Cleaved-caspase9 protein levels, whereas CE treatment significantly reversed the OGD/R-induced decrease in Bcl-2 and full length of caspase3 and caspase9 protein levels. In vivo, we found that CE treatment significantly ameliorated ischemic/hypoxic-induced brain infarct volume, neurological deficits, and neuronal apoptosis in mice after middle cerebral artery occlusion and reperfusion. CE treatment also significantly ameliorated the mitochondrial transmembrane potential, decreased Cytochrome C release, and reversed the increase in Bax, Cleaved-caspase3 and Cleaved-caspase9 protein levels and the decrease in Bcl-2 and full length of caspase3 and caspase9 protein levels induced by cerebral ischemia/reperfusion (I/R). All these results indicated that CE treatment exerted a neuroprotective effect by ameliorating mitochondrial dysfunction during cerebral I/R injury.

A Review of Neuroprotective Effects and Mechanisms of Ginsenosides From Panax Ginseng in Treating Ischemic Stroke

Ischemic stroke has been considered one of the leading causes of mortality and disability worldwide, associated with a series of complex pathophysiological processes. However, effective therapeutic methods for ischemic stroke are still limited. Panax ginseng, a valuable traditional Chinese medicine, has been long used in eastern countries for various diseases. Ginsenosides, the main active ingredient of Panax ginseng, has demonstrated neuroprotective effects on ischemic stroke injury during the last decade. In this article, we summarized the pathophysiology of ischemic stroke and reviewed the literature on ginsenosides studies in preclinical and clinical ischemic stroke. Available findings showed that both major ginsenosides and minor ginsenosides (such as Rg3, Rg5, and Rh2) has a potential neuroprotective effect, mainly through attenuating the excitotoxicity, Ca²⁺ overload, mitochondria dysfunction, blood-brain barrier (BBB) permeability, anti-inflammation, anti-oxidative, anti-apoptosis, anti-pyroptosis, anti-autophagy, improving angiogenesis, and neurogenesis. Therefore, this review brings a current understanding of the mechanisms of ginsenosides in the treatment of ischemic stroke. Further studies, especially in clinical trials, will be important to confirm the clinical value of ginseng and ginsenosides.