Neuroprotective effects of irisin against cerebral ischemia/ reperfusion injury via Notch signaling pathway

Inhibition of the cGAS-STING pathway: contributing to the treatment of cerebral ischemia-reperfusion injury

The cGAS-STING pathway plays an important role in ischemia-reperfusion injury in the heart, liver, brain, and kidney, but its role and mechanisms in cerebral ischemia-reperfusion injury have not been systematically reviewed. Here, we outline the components of the cGAS-STING pathway and then analyze its role in autophagy, ferroptosis, cellular pyroptosis, disequilibrium of calcium homeostasis, inflammatory responses, disruption of the blood-brain barrier, microglia transformation, and complement system activation following cerebral ischemia-reperfusion injury. We further analyze the value of cGAS-STING pathway inhibitors in the treatment of cerebral ischemia-reperfusion injury and conclude that the pathway can regulate cerebral ischemia-reperfusion injury through multiple mechanisms. Inhibition of the cGAS-STING pathway may be helpful in the treatment of cerebral ischemia-reperfusion injury.

The cerebroprotection and prospects of FNDC5/irisin in stroke

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

Deciphering the neuroprotective mechanisms of RACK1 in cerebral ischemia-reperfusion injury: Pioneering insights into mitochondrial autophagy and the PINK1/Parkin axis

INTRODUCTION

Cerebral ischemia-reperfusion injury (CIRI) is a common and debilitating complication of cerebrovascular diseases such as stroke, characterized by mitochondrial dysfunction and cell apoptosis. Unraveling the molecular mechanisms behind these processes is essential for developing effective CIRI treatments. This study investigates the role of RACK1 (receptor for activated C kinase 1) in CIRI and its impact on mitochondrial autophagy.

METHODS

We utilized high-throughput transcriptome sequencing and weighted gene co-expression network analysis (WGCNA) to identify core genes associated with CIRI. In vitro experiments used human neuroblastoma SK-N-SH cells subjected to oxygen and glucose deprivation (OGD) to simulate ischemia, followed by reperfusion (OGD/R). RACK1 knockout cells were created using CRISPR/Cas9 technology, and cell viability, apoptosis, and mitochondrial function were assessed. In vivo experiments involved middle cerebral artery occlusion/reperfusion (MCAO/R) surgery in rats, evaluating neurological function and cell apoptosis.

RESULTS

Our findings revealed that RACK1 expression increases during CIRI and is protective by regulating mitochondrial autophagy through the PINK1/Parkin pathway. In vitro, RACK1 knockout exacerbated cell apoptosis, while overexpression of RACK1 reversed this process, enhancing mitochondrial function. In vivo, RACK1 overexpression reduced cerebral infarct volume and improved neurological deficits. The regulatory role of RACK1 depended on the PINK1/Parkin pathway, with RACK1 knockout inhibiting PINK1 and Parkin expression, while RACK1 overexpression restored them.

CONCLUSION

This study demonstrates that RACK1 safeguards against neural damage in CIRI by promoting mitochondrial autophagy through the PINK1/Parkin pathway. These findings offer crucial insights into the regulation of mitochondrial autophagy and cell apoptosis by RACK1, providing a promising foundation for future CIRI treatments.

The role of m6A modification in the risk prediction and Notch1 pathway of Alzheimer's disease

N6-methyladenosine (m6A) methylation and abnormal immune responses are implicated in neurodegenerative diseases, yet their relationship in Alzheimer's disease (AD) remains unclear. We obtained AD datasets from GEO databases and used AD mouse and cell models, observing abnormal expression of m6A genes in the AD group, alongside disruptions in the immune microenvironment. Key m6A genes (YTHDF2, LRPPRC, and FTO) selected by machine learning were associated with the Notch pathway, with FTO and Notch1 displaying the strongest correlation. Specifically, FTO expression decreased and m6A methylation of Notch1 increased in AD mouse and cell models. We further silenced FTO expression in HT22 cells, resulting in upregulation of the Notch1 signaling pathway. Additionally, increased Notch1 expression in dendritic cells heightened inflammatory cytokine secretion in vitro. These results suggest that reduced FTO expression may contribute to the pathogenesis of AD by activating the Notch1 pathway to interfere with the immune response.

FNDC5/Irisin in dementia and cognitive impairment: update and novel perspective

Epidemiological surveys show that the incidence of age-related dementia and cognitive impairment is increasing and it has been a heavy burden for society, families, and healthcare systems, making the preservation of cognitive function in an increasingly aging population a major challenge. Exercise is beneficial for brain health, and FDNC5/irisin, a new exercise-induced myokine, is thought to be a beneficial mediator to cognitive function and plays an important role in the crosstalk between skeletal muscle and brain. This review provides a critical assessment of the recent progress in both fundamental and clinical research of FDNC5/irisin in dementia and cognitive impairment-related disorders. Furthermore, we present a novel perspective on the therapeutic effectiveness of FDNC5/irisin in alleviating these conditions.

L-DOPA ameliorates hippocampus-based mitochondria respiratory dysfunction caused by GCI/R injury

Mitochondrial dysmorphology/dysfunction follow global cerebral ischemia-reperfusion (GCI/R) injury, leading to neuronal death. Our previous researches demonstrated that Levodopa (L-DOPA) improves learning and memory impairment in GCI/R rats by increasing synaptic plasticity of hippocampal neurons. This study investigates if L-DOPA, used in Parkinson's disease treatment, alleviates GCI/R-induced cell death by enhancing mitochondrial quality. Metabolomics and transcriptomic results showed that GCI/R damage affected the Tricarboxylic acid (TCA) cycle in the hippocampus. The results of this study show that L-DOPA stabilized mitochondrial membrane potential and ultrastructure in hippocampus of GCI/R rats, increased dopamine level in hippocampus, decreased succinic acid level, and stabilized Ca2+ level in CA1 subregion of hippocampus. As a precursor of dopamine, L-DOPA is presumed to improves mitochondrial function in hippocampus of GCI/R rats. However, dopamine cannot cross the blood-brain barrier, so L-DOPA is used in clinical therapy to supplement dopamine. In this investigation, OGD/R models were established in isolated mouse hippocampal neurons (HT22) and primary rat hippocampal neurons. Notably, dopamine exhibited a multifaceted impact, demonstrating inhibition of mitochondrial reactive oxygen species (mitoROS) production, stabilization of mitochondrial membrane potential and Ca2+ level, facilitation of TCA circulation, promotion of aerobic respiratory metabolism, and downregulation of succinic acid-related gene expression. Consistency between in vitro and in vivo results underscores dopamine's significant neuroprotective role in mitigating mitochondrial dysfunction following global cerebral hypoxia and ischemia injury. Supplement dopamine may represent a promising therapy to the cognitive impairment caused by GCI/R injury.

The protective effect and mechanism of glycosides of cistanche deserticola on rats in middle cerebral artery occlusion (MCAO) model

Cerebral ischemia-reperfusion injury (CIRI) occurs frequently clinically as a complication following cardiovascular resuscitation resulting in neuronal damage specifically to the hippocampal CA1 region with consequent cognitive impairment. Apoptosis and oxidative stress were proposed as major risk factors associated with CIRI development. Previously, glycosides obtained from Cistanche deserticola (CGs) were shown to play a key role in counteracting CIRI; however, the underlying mechanisms remain to be determined. This study aimed to investigate the neuroprotective effect of CGs on subsequent CIRI in rats. The model of CIRI was established for 2 hr and reperfusion for 24 hr by middle cerebral artery occlusion (MCAO) model. The MCAO rats were used to measure the antioxidant and anti-apoptotic effects of CGs on CIRI. Neurological function was evaluated by the Longa neurological function score test. 2,3,5-Triphenyltetrazolium chloride (TTC) staining was used to detect the area of cerebral infarction. Nissl staining was employed to observe neuronal morphology. TUNEL staining was used to detect neuronal apoptosis, while Western blot determined protein expression levels of factors for apoptosis-related and PI3K/AKT/Nrf2 signaling pathway. Data demonstrated that CGs treatment improved behavioral performance, brain injury, and enhanced antioxidant and anti-apoptosis in CIRI rats. In addition, CGs induced activation of PI3K/AKT/Nrf2 signaling pathway accompanied by inhibition of the expression of apoptosis-related factors. Evidence indicates that CGs amelioration of CIRI involves activation of the PI3K/AKT/Nrf2 signaling pathway associated with increased cellular viability suggesting these glycosides may be considered as an alternative compound for CIRI treatment.

Treatment with β-sitosterol ameliorates the effects of cerebral ischemia/reperfusion injury by suppressing cholesterol overload, endoplasmic reticulum stress, and apoptosis

β-Sitosterol is a type of phytosterol that occurs naturally in plants. Previous studies have shown that it has anti-oxidant, anti-hyperlipidemic, anti-inflammatory, immunomodulatory, and anti-tumor effects, but it is unknown whether β-sitosterol treatment reduces the effects of ischemic stroke. Here we found that, in a mouse model of ischemic stroke induced by middle cerebral artery occlusion, β-sitosterol reduced the volume of cerebral infarction and brain edema, reduced neuronal apoptosis in brain tissue, and alleviated neurological dysfunction; moreover, β-sitosterol increased the activity of oxygen- and glucose-deprived cerebral cortex neurons and reduced apoptosis. Further investigation showed that the neuroprotective effects of β-sitosterol may be related to inhibition of endoplasmic reticulum stress caused by intracellular cholesterol accumulation after ischemic stroke. In addition, β-sitosterol showed high affinity for NPC1L1, a key transporter of cholesterol, and antagonized its activity. In conclusion, β-sitosterol may help treat ischemic stroke by inhibiting neuronal intracellular cholesterol overload/endoplasmic reticulum stress/apoptosis signaling pathways.

Sesamol defends neuronal damage following cerebral ischemia/reperfusion: a crosstalk of autophagy and Notch1/NLRP3 inflammasome signaling

OBJECTIVE

Sesamol (SES) is a phenolic compound found in sesame seed oil. Several studies have revealed its anti-inflammatory and antioxidant properties. However, its complete underlying mechanistic perspective about cerebral ischemia/reperfusion (I/R) lesions has not yet been disclosed. Consequently, we aimed to scrutinize its neuroprotective mechanism against cerebral injury during a global cerebral I/R in a rat model, considering its impact on autophagy and Notch1/NLRP3 inflammasome signaling regulation.

METHODS

To affirm our purpose, adult Wistar rats were allotted into five groups: sham and the other four groups in which transient global cerebral ischemia was induced by bilateral common ligation (2VO) for 1 h, then reperfusion for either 24 h or 5 days: I/R (1/24), I/R (1/5), SES + I/R (1/24), and SES + I/R (1/5). In treated groups, SES (100 mg/kg, p.o., for 21 days) was administered before cerebral I/R induction. The assessment of histopathological changes in brain tissues, immunohistochemistry, biochemical assays, ELISA, and qRT-PCR were utilized to investigate our hypothesis.

RESULTS

Advantageously, SES halted the structural neuronal damage with lessened demyelination induced by cerebral I/R injury. Restoring oxidant/antioxidant balance was evident by boosting the total antioxidant capacity and waning lipid peroxidation. Furthermore, SES reduced inflammatory and apoptosis markers. Additionally, SES recovered GFAP, Cx43, and autophagy signaling, which in turn switched off the Notch-1/NLRP3 inflammasome trajectory.

CONCLUSIONS

Our results revealed the neuroprotective effect of SES against cerebral I/R injury through alleviating injurious events and boosting autophagy, consequently abolishing Notch1/NLRP3 inflammasome signaling.

Sinigrin improves cerebral ischaemia-reperfusion injury by inhibiting the TLR4 pathway-mediated oxidative stress

Cerebral ischaemia-reperfusion (CIR) injury occurs in stroke patients after the restoration of cerebral perfusion. Sinigrin, a phytochemical found in cruciferous vegetables, exhibits strong antioxidant activity. This study investigated the role of sinigrin in oxidative stress using a CIR injury model. The effects of sinigrin were studied in middle cerebral artery occlusion (MCAO) rats and oxygen-glucose deprivation/reoxygenation (OGD/R)-injured SH-SY5Y cells. Sinigrin treatment improved brain injury and neurological deficits induced by MCAO surgery in rats. Sinigrin inhibited apoptosis in brain tissues and SH-SY5Y cells following OGD/R induction. Additionally, sinigrin elevated the levels of superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-Px) while reducing malondialdehyde (MDA) levels. Furthermore, sinigrin inhibited the toll-like receptor 4 (TLR4)/myeloid differentiation factor 88 (MyD88) signalling pathway. The anti-apoptotic and antioxidant activities of sinigrin in OGD/R-injured SH-SY5Y cells were reversed by TLR4 overexpression. In conclusion, sinigrin inhibits oxidative stress in CIR injury by suppressing the TLR4/MyD88 signalling pathway.

Ginkgolide B attenuates cerebral ischemia-reperfusion injury via inhibition of ferroptosis through disrupting NCOA4-FTH1 interaction

ETHNOPHARMACOLOGICAL RELEVANCE

Cerebral ischemia/reperfusion (I/R) injury is a major cause of neuronal damage and death. Ginkgolide B (GB) has been shown to exhibit neuroprotective effects in various brain injury models.

AIM OF STUDY

The aim of study was to investigate the potential role of GB in protecting against cerebral I/R injury and explore the underlying mechanisms.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats were exposed to transient middle cerebral artery occlusion (tMCAO) followed by reperfusion in order to trigger cerebral I/R injury. The rats were treated with different doses of GB, vehicle control or positive drug. Neurological function, infarct volume, and levels of ferroptosis markers were evaluated. In vitro experiments were performed using OGD/R-induced PC12 cells to further investigate the effects of GB on ferroptosis and its mechanisms. In addition, molecular docking, and microscale thermophoresis (MST) assay were conducted to explore the combination of GB and NCOA4.

RESULTS

Reduced infarct volume and enhanced neurological function were signs of dose-dependent protection from cerebral I/R injury by GB therapy. Additionally, GB treatment had an impact on the levels of oxidative stress and ferroptosis markers, including reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and Fe2+ in the cerebral environment during IR injury. Moreover, relevant ferroptosis key factors such as ACSL4, GPX4, FTH1, and NCOA4 can be regulated by GB. In OGD/R-induced PC12 cells, GB protected against ferroptosis by inhibiting autophagy and disrupting the interaction of NCOA4-FTH1.

CONCLUSION

Our findings suggest that GB may protect against cerebral I/R injury by inhibiting ferroptosis through disrupting NCOA4-FTH1 interaction. GB has potential therapeutic applications for cerebral I/R injury, and further investigation of the underlying mechanisms and clinical trials are warranted.

Ischemia-reperfusion injury: molecular mechanisms and therapeutic targets

Ischemia-reperfusion (I/R) injury paradoxically occurs during reperfusion following ischemia, exacerbating the initial tissue damage. The limited understanding of the intricate mechanisms underlying I/R injury hinders the development of effective therapeutic interventions. The Wnt signaling pathway exhibits extensive crosstalk with various other pathways, forming a network system of signaling pathways involved in I/R injury. This review article elucidates the underlying mechanisms involved in Wnt signaling, as well as the complex interplay between Wnt and other pathways, including Notch, phosphatidylinositol 3-kinase/protein kinase B, transforming growth factor-β, nuclear factor kappa, bone morphogenetic protein, N-methyl-D-aspartic acid receptor-Ca2+-Activin A, Hippo-Yes-associated protein, toll-like receptor 4/toll-interleukine-1 receptor domain-containing adapter-inducing interferon-β, and hepatocyte growth factor/mesenchymal-epithelial transition factor. In particular, we delve into their respective contributions to key pathological processes, including apoptosis, the inflammatory response, oxidative stress, extracellular matrix remodeling, angiogenesis, cell hypertrophy, fibrosis, ferroptosis, neurogenesis, and blood-brain barrier damage during I/R injury. Our comprehensive analysis of the mechanisms involved in Wnt signaling during I/R reveals that activation of the canonical Wnt pathway promotes organ recovery, while activation of the non-canonical Wnt pathways exacerbates injury. Moreover, we explore novel therapeutic approaches based on these mechanistic findings, incorporating evidence from animal experiments, current standards, and clinical trials. The objective of this review is to provide deeper insights into the roles of Wnt and its crosstalk signaling pathways in I/R-mediated processes and organ dysfunction, to facilitate the development of innovative therapeutic agents for I/R injury.

Batokine in Central Nervous System Diseases

Brown adipose tissue (BAT) is a special type of fat tissue in mammals and is also a key endocrine organ in the human body. Batokine, the endocrine effector of BAT, plays a neuroprotective role and improves the prognosis by exerting anti-apoptotic and anti-inflammatory effects, as well as by improving vascular endothelial function and other mechanisms in nerve injury diseases. The present article briefly reviewed several types of batokines related to central nervous system (CNS) diseases. Following this, the potential therapeutic value and future research direction of batokines for CNS diseases were chiefly discussed from the aspects of protective mechanism and signaling pathway.

Sertraline Pre-Treatment Attenuates Hemorrhagic Transformation Induced in Rats after Cerebral Ischemia Reperfusion via Down Regulation of Neuronal CD163: Involvement of M1/M2 Polarization Interchange and Inhibiting Autophagy

Cerebral ischemia reperfusion (I/R) is one of the neurovascular diseases which leads to severe brain deterioration. Haemorrhagic transformation (HT) is the main complication of ischemic stroke. It exacerbates by reperfusion, causing a more deleterious effect on the brain and death. The current study explored the protective effect of sertraline (Sert) against cerebral I/R in rats by inhibiting HT, together with the molecular pathways involved in this effect. Forty-eight wister male rats were divided into 4 groups: Sham, Sert + Sham, I/R, and Sert + I/R. The ischemic model was induced by bilateral occlusion of the common carotid artery for 20 min, then reperfusion for 24 h. Sertraline (20 mg/kg, p.o.) was administrated for 14 days before exposure to ischemia. Pre-treatment with Sert led to a significant attenuation of oxidative stress and inflammation. In addition, Sert attenuated phosphorylation of extracellular regulated kinases and nuclear factor kappa-p65 expression, consequently modulating microglial polarisation to M2 phenotype. Moreover, Sert prevented the hemorrhagic transformation of ischemic stroke as indicated by the notable decrease in neuronal expression of CD163, activity of Heme oxygenase-2 and matrix metalloproteinase-2 and 9 levels. In the same context, Sert decreased levels of autophagy and apoptotic markers. Furthermore, histological examination, Toluidine blue, and Prussian blue stain aligned with the results. In conclusion, Sert protected against cerebral I/R damage by attenuating oxidative stress, inflammation, autophagy, and apoptotic process. It is worth mentioning that our study was the first to show that Sert inhibited hemorrhagic transformation. The protective effect of sertraline against injury induced by cerebral ischemia reperfusion via inhibiting Hemorrhagic transformation.

Disorders of the central nervous system: Insights from Notch and Nrf2 signaling

The functional complexity of the central nervous system (CNS) is unparalleled in living organisms. It arises from neural crest-derived cells that migrate by the exact route, leading to the formation of a complex network of neurons and glial cells. Recent studies have shown that novel crosstalk exists between the Notch1 and Nrf2 pathways and is associated with many neurological diseases. The Notch1-Nrf2 axis may act on nervous system development, and the molecular mechanism has recently been reported. In this review, we summarize the essential structure and function of the CNS. The significance of interactions between signaling pathways and between developmental processes like proliferation, apoptosis and migration in ensuring the correct development of the CNS is also presented. We primarily focus on research concerning possible mechanism of interaction between Notch1 and Nrf2 and the functions of Notch1-Nrf2 in neurons. There may be a direct interaction between Notch1 and NRF2, which is closely related to the crosstalk that occurs between them. The significance and potential applications of the Notch1-Nrf2 axis in abnormal development of the nervous system are been highlighten. We also discuss the molecular mechanisms by which the Notch1-Nrf2 axis controls the apoptosis, antioxidant pathway and differentiation of neurons to modulate the development of the nervous system. This information will lead to a better understanding of Notch1-Nrf2 axis signaling pathways in the nervous system and may facilitate the development of new therapeutic strategies.

Physical Exercise as Disease-Modifying Alternative against Alzheimer's Disease: A Gut-Muscle-Brain Partnership

Alzheimer's disease (AD) is a common cause of dementia characterized by neurodegenerative dysregulations, cognitive impairments, and neuropsychiatric symptoms. Physical exercise (PE) has emerged as a powerful tool for reducing chronic inflammation, improving overall health, and preventing cognitive decline. The connection between the immune system, gut microbiota (GM), and neuroinflammation highlights the role of the gut-brain axis in maintaining brain health and preventing neurodegenerative diseases. Neglected so far, PE has beneficial effects on microbial composition and diversity, thus providing the potential to alleviate neurological symptoms. There is bidirectional communication between the gut and muscle, with GM diversity modulation and short-chain fatty acid (SCFA) production affecting muscle metabolism and preservation, and muscle activity/exercise in turn inducing significant changes in GM composition, functionality, diversity, and SCFA production. This gut-muscle and muscle-gut interplay can then modulate cognition. For instance, irisin, an exercise-induced myokine, promotes neuroplasticity and cognitive function through BDNF signaling. Irisin and muscle-generated BDNF may mediate the positive effects of physical activity against some aspects of AD pathophysiology through the interaction of exercise with the gut microbial ecosystem, neural plasticity, anti-inflammatory signaling pathways, and neurogenesis. Understanding gut-muscle-brain interconnections hold promise for developing strategies to promote brain health, fight age-associated cognitive decline, and improve muscle health and longevity.

Nordic Walking training in BungyPump form improves cognitive functions and physical performance and induces changes in amino acids and kynurenine profiles in older adults

Introduction

Although impacts of physical activity on cognitive functions have been intensively investigated, they are still far from being completely understood. The aim of this study was to evaluate the effect of 12 weeks of the Nordic Walking training with BungyPump resistance poles (NW-RSA) on the amino acid and kynurenine profiles as well as selected myokine/exerkine concentrations, which may modify the interface between physical and cognitive functions.

Methods

A group of 32 older adults participated in the study. Before and after the intervention, body composition, cognitive functions, and physical performance were assessed. Blood samples were taken before and 1 h after the first and last sessions of the NW-RSA training, to determine circulating levels of exercise-induced proteins, i.e., brain-derived neurotrophic factor (BDNF), irisin, kynurenine (KYN), metabolites, and amino acids.

Results

The NW-RSA training induced a significant improvement in cognitive functions and physical performance as well as a reduction in fat mass (p = 0.05). Changes were accompanied by a decline in resting serum BDNF (p = 0.02) and a slight reduction in irisin concentration (p = 0.08). Still, changes in irisin concentration immediately after the NW-RSA intervention depended on shifts in kynurenine-irisin dropped as kynurenine increased. The kynurenine-to-tryptophan and phenylalanine-to-tyrosine ratios decreased significantly, suggesting their possible involvement in the amelioration of cognitive functions. No changes of glucose homeostasis or lipid profile were found. Shifts in the concentrations of selected amino acids might have covered the increased energy demand in response to the NW-RSA training and contributed to an improvement of physical performance.

Conclusion

Regular Nordic Walking training with additional resistance (BungyPump) improved cognitive functions and physical performance. These positive effects were associated with a reduced BDNF concentration and kynurenine-to-tryptophan ratio as well as changes in the amino acid profile.

Berberine modulates gut microbiota to attenuate cerebral ferroptosis induced by ischemia-reperfusion in mice

Ferroptosis was reported to be involved in cerebral ischemia-reperfusion injury (CIRI), on which the effects of berberine (BBR) remain unclear. Moreover, based on the critical role of gut microbiota in pleiotropic actions of BBR, we hypothesized that BBR can suppress CIRI-induced ferroptosis by modulating the gut microbiota. In this study, the results showed that BBR obviously attenuated the behavioral deficits of CIRI mice, accompanied with the improved survival rate and neuron damages, as phenocopied by dirty cage experiment. The typical morphological changes in ferroptotic cells and biomarkers of ferroptosis were attenuated in BBR- and its fecal microbiota-treated mice, accompanied by reduced malondialdehyde and reactive oxygen species, and the increased glutathione (GSH). BBR was found to alter the gut microbiota of CIRI mice with decreased abundance of Muribaculaceae, Erysipelotrichaceae, Helicobacteraceae, Streptococcaceae and Tannerellaceae, but elevated Bacteroidaceae and Enterobacteriaceae. KEGG analysis based on the 16S rRNA results indicated that multiple metabolic pathways including ferroptosis and GSH metabolism, were altered by BBR. Oppositely, the antibiotics administration counteracted the protective properties of BBR. Summarily, this study revealed the therapeutic potential of BBR on CIRI via inhibiting neuronal ferroptosis, in which upregulated glutathione peroxidase 1 (GPX1) was possibly involved. Moreover, the BBR-modulated gut microbiota was shown to play the critical role in the underlying mechanism.

Liensinine ameliorates ischemia-reperfusion-induced brain injury by inhibiting autophagy via PI3K/AKT signaling

The current study aimed to explore the role of autophagy in cerebral ischemia-reperfusion injuries (CIRI) and elucidate the efficacy of liensinine treatment. An in vitro ischemia-reperfusion (I/R) neuronal cell model was established and pretreated with liensinine or rapamycin (RAPA). Cell proliferation and survival were detected using a cell counting kit-8 (CCK-8) assay, while cell damage and apoptosis were detected using the lactate dehydrogenase (LDH) leakage rate and flow cytometry. Autophagy activity was detected using monodansylcadaverine (MDC) staining. Thereafter, I/R models were established in vivo in rats and the presence of neurological deficits was examined. Hematoxylin-eosin (HE) and triphenyl tetrazolium chloride (TTC) staining was used to detect pathological damage in brain tissue and the volume ratio of the cerebral infarction. The levels of PI3K/AKT pathway-related proteins and autophagy-related proteins (mTOR, LC3, P62, and TSC2) were detected using Western blot. The findings showed that liensinine treatment increased cell viability, decreased cell injury and apoptosis, and inhibited autophagy. The addition of RAPA to promote autophagy inhibited cell viability and enhanced cell injury and apoptosis. The I/R rats in the model group exhibited deficient neurological function, while those in the liensinine treatment group showed restoration of normal neural function and reduction of the necrotic area and infarct volume ratio in the brain tissue. Furthermore, liensinine treatment also inhibited the PI3K/Akt pathway activity and autophagy. However, addition of RAPA reversed the effects of liensinine treatment and aggravated brain tissue injury. Therefore, liensinine can play a neuroprotective role in CIRI by inhibiting autophagy through regulation of the PI3K/Akt pathway.

Ginkgolide C attenuates cerebral ischemia/reperfusion-induced inflammatory impairments by suppressing CD40/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ginkgo biloba L. (Ginkgoaceae), a traditional Chinese medicine, has been applied for thousands of years for the treatment of cardio-cerebral vascular diseases in China. It is written in Compendium of Materia Medica that Ginkgo has the property of "dispersing poison", which is now referred to as anti-inflammatory and antioxidant. Ginkgolides are important active ingredients in Ginkgo biloba leaves and ginkgolide injection has been frequently applied in clinical practice for the treatment of ischemic stroke. However, few studies have explored the effect and mechanism of ginkgolide C (GC) with anti-inflammatory activity in cerebral ischemia/reperfusion injury (CI/RI).

AIM OF THE STUDY

The present study aimed to demonstrate whether GC was capable of attenuating CI/RI. Furthermore, the anti-inflammatory effect of GC in CI/RI was explored around the CD40/NF-κB pathway.

MATERIALS AND METHODS

In vivo, middle cerebral artery occlusion/reperfusion (MCAO/R) model was established in rats. The neuroprotective effect of GC was assessed by neurological scores, cerebral infarct rate, microvessel ultrastructure, blood-brain barrier (BBB) integrity, brain edema, neutrophil infiltration, and levels of TNF-α, IL-1β, IL-6, ICAM-1, VCAM-1, and iNOS. In vitro, rat brain microvessel endothelial cells (rBMECs) were preincubated in GC before hypoxia/reoxygenation (H/R) culture. The cell viability, levels of CD40, ICAM-1, MMP-9, TNF-α, IL-1β, and IL-6, and activation of NF-κB pathway were examined. In addition, the anti-inflammatory effect of GC was also investigated by silencing CD40 gene in rBMECs.

RESULTS

GC attenuated CI/RI as demonstrated by decreasing neurological scores, reducing cerebral infarct rate, improving microvessel ultrastructural features, ameliorating BBB disruption, attenuating brain edema, inhibiting MPO activity, and downregulating levels of TNF-α, IL-1β, IL-6, ICAM-1, VCAM-1, and iNOS. Coherently, in rBMECs exposed to H/R GC enhanced cell viability and downregulated levels of ICAM-1, MMP-9, TNF-α, IL-1β, and IL-6. Furthermore, GC suppressed CD40 overexpression and hindered translocation of NF-κB p65 from the cytosol to the nucleus, phosphorylation of IκB-α, and activation of IKK-β in H/R rBMECs. However, GC failed to protect rBMECs from H/R-induced inflammatory impairments and suppress activation of NF-κB pathway when CD40 gene was silenced.

CONCLUSIONS

GC attenuates cerebral ischemia/reperfusion-induced inflammatory impairments by suppressing CD40/NF-κB pathway, which may provide an available therapeutic drug for CI/RI.

Anti-apoptosis effect of traditional Chinese medicine in the treatment of cerebral ischemia-reperfusion injury

Cerebral ischemia, one of the leading causes of neurological dysfunction of brain cells, muscle dysfunction, and death, brings great harm and challenges to individual health, families, and society. Blood flow disruption causes decreased glucose and oxygen, insufficient to maintain normal brain tissue metabolism, resulting in intracellular calcium overload, oxidative stress, neurotoxicity of excitatory amino acids, and inflammation, ultimately leading to neuronal cell necrosis, apoptosis, or neurological abnormalities. This paper summarizes the specific mechanism of cell injury that apoptosis triggered by reperfusion after cerebral ischemia, the related proteins involved in apoptosis, and the experimental progress of herbal medicine treatment through searching, analyzing, and summarizing the PubMed and Web Of Science databases, which includes active ingredients of herbal medicine, prescriptions, Chinese patent medicines, and herbal extracts, providing a new target or new strategy for drug treatment, and providing a reference for future experimental directions and using them to develop suitable small molecule drugs for clinical application. With the research of anti-apoptosis as the core, it is important to find highly effective, low toxicity, safe and cheap compounds from natural plants and animals with abundant resources to prevent and treat Cerebral ischemia/reperfusion (I/R) injury (CIR) and solve human suffering. In addition, understanding and summarizing the apoptotic mechanism of cerebral ischemia-reperfusion injury, the microscopic mechanism of CIR treatment, and the cellular pathways involved will help to develop new drugs.

Exploring the synergic mechanism of Ligusticum striatum DC. and borneol in attenuating BMECs injury and maintaining tight junctions against cerebral ischaemia based on the HIF-1α/VEGF signalling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ligusticum striatum DC., also known as Ligusticum chuanxiong Hort. (LCH), is widely used in China for its excellent effect in ischaemic stroke (IS) patients, and borneol (BO) has been confirmed to maintain the blood‒brain barrier (BBB) after stroke. They are often used as a combination in the prescriptions of IS patients. Although the advantage of their combined treatment in improving brain ischaemia has been verified, their synergistic mechanism on BBB maintenance is still unclear.

AIM OF THE STUDY

This study was designed to evaluate the synergistic effect of maintaining the BBB between LCH and BO against IS and to further explore the potential mechanism.

MATERIALS AND METHODS

After primary mouse brain microvascular endothelial cells (BMECs) were extracted and identified, the duration of oxygen-glucose deprivation (OGD) and the doses of LCH and BO were optimized. Then, the cells were divided into five groups: control, model, LCH, BO, and LCH + BO. Cell viability, injury degree, proliferation and migration were detected by CCK-8, LDH, EdU and wound-healing assays, respectively. Hoechst 33342 staining was adopted to detect the apoptosis rate, and western blotting was employed to observe the expressions of Bax, Bcl-2, caspase-3 and cleaved caspase-3. The TEER value and NaF permeability were measured to assess tight junction (TJ) function, while ZO-1, occludin and claudin-5 were also probed by western blotting. Moreover, the HIF-1α/VEGF pathway was observed to explore the underlying mechanism of BBB maintenance. In vivo, global cerebral ischaemia/reperfusion (GCIR) surgery was performed to establish an IS model. After treatment with LCH (200 mg/kg) and/or BO (160 mg/kg), histopathological structure and BMECs repair were observed by HE staining and immunohistochemistry of vWF. Meanwhile, TJ-associated proteins in vivo were also detected by western blotting.

RESULTS

Basically, LCH and BO had different emphases. LCH significantly attenuated the vacuolar structure, nuclear pyknosis and neuronal loss of GCIR mice, while BO focused on promoting BMECs proliferation and angiogenesis and inhibiting the degradation of TJ-associated proteins in vivo after IS. Interestingly, their combination further enhanced these effects. OGD injury markedly reduced the viability, proliferation and migration of primary BMECs; decreased the ratio of Bcl-2/Bax, TEER value, and the expressions of ZO-1, occludin and claudin-5; induced LDH release and apoptosis; and increased the cleaved caspase-3/caspase-3 ratio and NaF permeability. Meanwhile, BO might be the main contributor to the combinative treatment in ameliorating OGD-induced damage of BMECs and degradation of TJ-related proteins, and the potential mechanism might be involved in upregulating the HIF-1α/VEGF signalling pathway. Although LCH showed no obvious improvement, it could enhance the therapeutic effect of BO. Interestingly, their combination even produced some new improvements, including the reduction of cleaved caspase-3 and increase in TEER value, none of which were exhibited in their monotherapies.

CONCLUSIONS

LCH and BO exhibited complementary therapeutic features in alleviating cerebral ischaemic injury by inhibiting BMECs apoptosis, maintaining the BBB and attenuating the loss of neurons. LCH preferred to protect ischaemic neurons, while BO played a key role in protecting BMECs, maintaining the BBB and TJs by activating the HIF-1α/VEGF signalling pathway.

Effects of Subchronic Propofol Administration on the Proliferation and Differentiation of Neural Stem Cells in Rat Hippocampus

Background

Although controversial, experimental data suggest the use of propofol may be associated with neurotoxicity. The mechanisms responsible for propofol neurotoxicity in animals are not yet clear.

Objective

This study aimed to determine the effects of propofol on the proliferation of neural stem cells in rat hippocampus and the mechanisms underlying these effects.

Methods

Forty-five adult male Sprague-Dawley rats were randomly divided into 5 groups: Control (N group), intralipid (V group), 30 mg/kg propofol (Prop30 group), 60 mg/kg propofol (Prop60 group), and 120 mg/kg propofol (Prop120 group). The rats in all groups received 5, once daily intraperitoneal injections. For each of the 5 days, the N group received 6 mL/kg normal saline, the V group received 6 mL/kg fat emulsion, the Prop30 group received 30 mg/kg propofol, the Prop60 group received 60 mg/kg propofol, and the Prop120 group received 120 mg/kg propofol. Memory function was scored daily using the Morris water maze test. Immunofluorescence staining was used to histologically monitor the proliferation and differentiation of the rats' hippocampal neural stem cells, and real time quantitative polymerase chain reaction and Western blotting were used to determine the expression of Notch3, Hes1, and Hes5.

Results

Compared with the N group, the Prop120 group exhibited reduced learning and memory, whereas there were no significant differences for the Prop60 group. The number of β-tubulin III⁺ cells increased in the Prop60 group, but decreased in the Prop120 group. Compared with the N group, the relative expression of Notch3 and Hes5 increased significantly in the Prop60 group, whereas this expression decreased in the Prop120 group.

Conclusions

These data demonstrate that repeated, subchronic (5 days) intraperitoneal injections of 60 mg/kg propofol can effectively promote rat hippocampal neural stem cells proliferation and differentiation, and that this is likely mediated by its effects on the Notch3-Hes5 pathway.

PUM2 aggravates the neuroinflammation and brain damage induced by ischemia-reperfusion through the SLC7A11-dependent inhibition of ferroptosis via suppressing the SIRT1

Cerebral ischemia-reperfusion (I/R) injury occurs due to the restoration of blood perfusion after cerebral ischemia, which results in the damage of the brain structures and functions. Unfortunately, currently there are no effective methods for preventing and treating it. The pumilio 2 (PUM2) is a type of RBPs that has been reported to participate in the progression of several diseases. Ferroptosis is reported to be involved in I/R injury. Whether PUM2 modulated I/R injury through regulating ferroptosis remains to be elucidated. The cerebral I/R models including animal middle cerebral artery occlusion/reperfusion (MCAO/R) model and oxygen-glucose deprivation/reperfusion (OGD/R)-induced cortical neuron injury cell model of were established and, respectively. RT-qPCR was applied for evaluating PUM2, SIRT1 and SLC7A11 expression. Western blot was employed for measuring the protein expression levels. The viability of cortical neurons was tested by MTT assay. The histological damage of the brain tissues was assessed by H&E staining. The level of PUM2 was boosted in both the brain tissues of the MCAO model and OGD/R-induced cortical neuron injury model. Silence of PUM2 alleviated MCAO-induced brain injury and decreased the death of PC12 cell exposed to OGD/R. PUM2 also aggravated the accumulation of free iron in MCAO mice and OGD/R-induced cortical neuron injury model. In addition, PUM2 suppressed SLC7A11 via inhibiting expression of SIRT1. Rescue assays unveiled that downregulation of SLC7A11 reversed PUM2 mediated neuroinflammation and brain damage induced by I/R. PUM2 aggravated I/R-induced neuroinflammation and brain damage through the SLC7A11-dependent inhibition of ferroptosis by suppressing SIRT1, highlighting the role of PUM2 in preventing or treating cerebral I/R injury.

Irisin: A bridge between exercise and neurological diseases

Exercise plays a beneficial regulating role on each organ of the body through different mechanisms and is a powerful weapon to prevent disease. Irisin is released from muscle and widely distributed in the human body, participating in the physiological processes of multiple human systems and playing a protective role in multiple human organs. The protective effect of irisin on the nervous system is particularly remarkable, which can improve cognitive function, reduce the risk of ischemic stroke and improve its prognosis. Irisin also plays a guiding role in the prevention and treatment of neurodegenerative diseases and ischemic cerebrovascular diseases. Exercise is the driving factor promoting irisin secretion, and different exercise modes, intensity, frequency, and time all affect the level of serum irisin. As a result of analyzing the effects of various exercise modes on irisin secretion, we proposed an exercise program with a higher level of irisin secretion.

Spinal Irisin Gene Delivery Attenuates Burn Injury-Induced Muscle Atrophy by Promoting Axonal Myelination and Innervation of Neuromuscular Junctions

Muscle loss and weakness after a burn injury are typically the consequences of neuronal dysregulation and metabolic change. Hypermetabolism has been noted to cause muscle atrophy. However, the mechanism underlying the development of burn-induced motor neuropathy and its contribution to muscle atrophy warrant elucidation. Current therapeutic interventions for burn-induced motor neuropathy demonstrate moderate efficacy and have side effects, which limit their usage. We previously used a third-degree burn injury rodent model and found that irisin-an exercise-induced myokine-exerts a protective effect against burn injury-induced sensory and motor neuropathy by attenuating neuronal damage in the spinal cord. In the current study, spinal irisin gene delivery was noted to attenuate burn injury-induced sciatic nerve demyelination and reduction of neuromuscular junction innervation. Spinal overexpression of irisin leads to myelination rehabilitation and muscular innervation through the modulation of brain-derived neurotrophic factor and glial-cell-line-derived neurotrophic factor expression along the sciatic nerve to the muscle tissues and thereby modulates the Akt/mTOR pathway and metabolic derangement and prevents muscle atrophy.

The mechanisms underlying the actions of Xuefu Zhuyu decoction pretreatment against neurological deficits after ischemic stroke in mice: The mediation of glymphatic function by aquaporin-4 and its anchoring proteins

Ischemic stroke (IS) has been associated with an impairment in glymphatic function. Xuefu Zhuyu Decoction (XFZYD) is widely used in the prevention and treatment of ischemic stroke. We hypothesized that Xuefu Zhuyu decoction pretreatment could attenuate early neurological deficits after ischemic stroke by enhancing the function of the glymphatic system. To prove our hypothesis, we carried out temporary middle cerebral artery occlusion and reperfusion surgery on C57BL/6 mice and then measured neurological score, infarct size and performed hematoxylin-eosin staining to assess stroke outcomes after 24 h of reperfusion. Subsequently, we injected fluorescent tracers in to the cisterna magna and evaluated tracer distribution in coronal brain sections. The polarization of aquaporin-4 (AQP4), colocalization of aquaporin-4, α-dystroglycan, β-dystroglycan and agrin were determined by immunofluorescence. Our research showed that pretreatment with Xuefu Zhuyu decoction significantly alleviated neurological scores, neurological deficits and pathological abnormalities in a mouse model of ischemic stroke. Importantly, Xuefu Zhuyu decoction pretreatment enhanced cerebrospinal fluid influx, protected aquaporin-4 depolarization and promoted the colocalization of aquaporin-4 with its anchoring proteins in the brain. Our findings highlight novel mechanisms underlying the neuroprotective effect of Xuefu Zhuyu decoction pretreatment on ischemic stroke-induced brain damage through the glymphatic system. Xuefu Zhuyu decoction pretreatment may offer a promising approach to slow the onset and progression of ischemic stroke.

Patchouli alcohol protects against myocardial ischaemia-reperfusion injury by regulating the Notch1/Hes1 pathway

CONTEXT

Patchouli alcohol (PA) has protective effects on cerebral ischaemia/reperfusion (I/R) injury, but its efficacy on myocardial ischaemia-reperfusion (MI/R) has yet to be addressed.

OBJECTIVE

To examine the therapeutic effect of PA on myocardial ischaemia-reperfusion (I/R) injury.

MATERIALS AND METHODS

C57BL/6 male mice were randomly divided into sham, MI/R, MI/R + PA-10, MI/R + PA-20 and MI/R + PA-40 groups. In vivo MI/R model was established by ligating the anterior descending coronary artery of the heart. In vitro stimulated IR cell model was constructed by using the rat cardiomyocyte H9C2 cell line. Mice in the treatment groups were intraperitoneally injected with PA (10, 20, 40 mg/kg) for 30 days then subjected to surgery, and cells in the experimental group were pre-treated with PA (1, 10 or 100 μmol/L). After treatment, mouse heart function, myocardial injury markers, myocardial infarction and Notch1/Hes1 expression, endoplasmic reticulum stress markers, and apoptosis-related proteins were determined.

RESULTS

In vivo, PA treatment improved hemodynamic parameter changes and myocardial enzymes, increased the left ventricular ejection fraction and left ventricular fractional shortening, reduced the left ventricular end-systolic diameter and inhibited CK-MB, cTnI and cTnT levels. In addition, PA attenuated myocardial tissue damage and apoptosis. PA treatment elevated Notch1, NICD and Hes1 levels and suppressed the levels of ATF4, p-PERK/PERK, and cleaved caspase-3/caspase-3 in vitro and in vivo.

DISCUSSION AND CONCLUSION

PA protects against MI/R, possibly by modulating ER stress, apoptosis and the Notch1/Hes1 signalling pathways. These findings indicate that PA may be a promising candidate for treating ischaemic heart diseases.

Anti-Seizure and Neuronal Protective Effects of Irisin in Kainic Acid-Induced Chronic Epilepsy Model with Spontaneous Seizures

An increased level of reactive oxygen species is a key factor in neuronal apoptosis and epileptic seizures. Irisin reportedly attenuates the apoptosis and injury induced by oxidative stress. Therefore, we evaluated the effects of exogenous irisin in a kainic acid (KA)-induced chronic spontaneous epilepsy rat model. The results indicated that exogenous irisin significantly attenuated the KA-induced neuronal injury, learning and memory defects, and seizures. Irisin treatment also increased the levels of brain-derived neurotrophic factor (BDNF) and uncoupling protein 2 (UCP2), which were initially reduced following KA administration. Furthermore, the specific inhibitor of UCP2 (genipin) was administered to evaluate the possible protective mechanism of irisin. The reduced apoptosis, neurodegeneration, and spontaneous seizures in rats treated with irisin were significantly reversed by genipin administration. Our findings indicated that neuronal injury in KA-induced chronic epilepsy might be related to reduced levels of BDNF and UCP2. Moreover, our results confirmed the inhibition of neuronal injury and epileptic seizures by exogenous irisin. The protective effects of irisin may be mediated through the BDNF-mediated UCP2 level. Our results thus highlight irisin as a valuable therapeutic strategy against neuronal injury and epileptic seizures.

DJ-1 Protein Inhibits Apoptosis in Cerebral Ischemia by Regulating the Notch1 and Nuclear Factor Erythroid2-Related Factor 2 Signaling Pathways

DJ-1 plays a neuroprotective role in cerebral ischemia- reperfusion (I/R) injury and participates in the apoptosis of brain nerve cells, but the underlying mechanism is unclear. We explored the molecular pathways underlying this role using in vivo and in vitro approaches. Middle cerebral artery occlusion- reperfusion (MCAO/R) rat models and oxygen- glucose deprivation- reoxygenation (OGD/R) HAPI cell cultures were used to simulate cerebral ischemia-reperfusion injury. The interaction between DJ-1 and Notch1 was enhanced after MCAO/R in rats. After treatment of rats with DJ-1 siRNA, the expression of Notch1 and Nrf2 was down-regulated, and apoptosis was promoted. In contrast, the DJ-1 based peptide ND-13 upregulated the expression of Notch1 and Nrf2, and prevented apoptosis. In vitro, the Notch1 signaling pathway inhibitor DAPT reversed the neuroprotective effect of ND-13 and promoted apoptosis, weakened the interaction between DJ-1 and Notch1, and decreased the expression of proteins in the Notch1 and Nrf2 pathways. Thus, we found that DJ-1 inhibits apoptosis by regulating the Notch1 signaling pathway and Nrf2 expression in cerebral I/R injury. These results imply that DJ-1 is a potential therapeutic target for cerebral I/R injury.

New Therapeutic Approaches to and Mechanisms of Ginsenoside Rg1 against Neurological Diseases

Neurological diseases, including Parkinson’s disease (PD), Alzheimer’s disease (AD), Huntington’s disease (HD), stroke, cerebral infarction, ischemia-reperfusion injury, depression and, stress, have high incidence and morbidity and often lead to disability. However, there is no particularly effective medication against them. Therefore, finding drugs with a suitable efficacy, low toxicity and manageable effects to improve the quality of life of patients is an urgent problem. Ginsenoside Rg1 (Rg1) is the main active component of ginseng and has a variety of pharmacological effects. In this review, we focused on the therapeutic potential of Rg1 for improving neurological diseases. We introduce the mechanisms of Ginsenoside Rg1 in neurological diseases, including apoptosis, neuroinflammation, the microRNA (miRNA) family, the mitogen-activated protein kinase (MAPK) family, oxidative stress, nuclear factor-κB (NF-κB), and learning and memory of Rg1 in neurological diseases. In addition, Rg1 can also improve neurological diseases through the interaction of different signal pathways. The purpose of this review is to explore more in-depth ideas for the clinical treatment of neurological diseases (including PD, AD, HD, stroke, cerebral infarction, ischemia–reperfusion injury, depression, and stress). Therefore, Rg1 is expected to become a new therapeutic method for the clinical treatment of neurological diseases.

lncRNA DHFRL1‑4 knockdown attenuates cerebral ischemia/reperfusion injury by upregulating the levels of angiogenesis‑related genes

The present study aimed to investigate the effects of long non-coding (lncRNA) dihydrofolate reductase-like 1 (DHFRL1-4) on cerebral ischemia/reperfusion (I/R)-induced injury. For this purpose, mice injected with lentivirus with small interfering RNA targeting DHFRL1-4 or negative control siRNA were used to construct models of cerebral I/R injury. Following the establishment of the model, the infarct size, neurological deficit score, apoptosis and the expression levels of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), Wnt family member 3a (Wnt3a), glycogen synthase kinase-3β (GSK-3β) and phosphorylated GSK-3β were assessed. The expression of DHFRL1-4 was significantly upregulated in the I/R model. In the control and sham groups, the boundaries between the cortex and gray matter were clear, and no edema or necrosis were observed. The nerve cells were arranged orderly and evenly, and the cell membranes were intact with visible nucleus and nucleolus. In the model group however, the nerve fibers were slightly necrotic and swollen, and the number of nerve cells was reduced. In the mice injected with si-DHFRL1-4 lentivirus, the brain tissues exhibited less liquefaction and degeneration, as well as less edema. Compared with the control and sham groups, the model group had a significantly larger infarct area, a higher apoptotic rate, higher bFGF, VEGF, Wnt3a and GSK-3β expression levels and a greater neurological deficit score. However, the mice injected with si-DHFRL1-4 lentivirus exhibited a significantly reduced infarct area, a lower apoptotic rate, lower Wnt3a and GSK-3β expression levels, a lower neurological deficit score, and significantly upregulated bFGF and VEGF levels.

Irisin: A promising treatment for neurodegenerative diseases

The beneficial effects of exercise on human brain function have been demonstrated in previous studies. Myokines secreted by muscle have attracted increasing attention because of their bridging role between exercise and brain health. Regulated by PPARγ coactivator 1α, fibronectin type III domain-containing protein 5 releases irisin after proteolytic cleavage. Irisin, a type of myokine, is secreted during exercise, which induces white adipose tissue browning and relates to energy metabolism. Recently, irisin has been shown to exert a protective effect on the central nervous system. Irisin secretion triggers an increase in brain-derived neurotrophic factor levels in the hippocampus, contributing to the amelioration of cognition impairments. Irisin also plays an important role in the survival, differentiation, growth, and development of neurons. This review summarizes the role of irisin in neurodegenerative diseases and other neurological disorders. As a novel positive mediator of exercise in the brain, irisin may effectively prevent or decelerate the progress of neurodegenerative diseases in models and also improve cognitive functions. We place emphasis herein on the potential of irisin for prevention rather than treatment in neurodegenerative diseases. In ischemic diseases, irisin can alleviate the pathophysiological processes associated with stroke. Meanwhile, irisin has anxiolytic and antidepressant effects. The potential therapeutic effects of irisin in epilepsy and pain have been initially revealed. Due to the pleiotropic and beneficial properties of irisin, the possibility of irisin treating other neurological diseases could be gradually explored in the future.

Mechanism of CNS regulation by irisin, a multifunctional protein

Exercise not only builds up our body but also improves cognitive function. Skeletal muscle secretes myokine during exercise as a large reservoir of signaling molecules, which can be considered as a medium between exercise and brain health. Irisin is a circulating myokine derived from the Fibronectin type III domain-containing protein 5 (FNDC5). Irisin regulates energy metabolism because it can stimulate the "Browning" of white adipose tissue. It has been reported that irisin can cross the blood-brain barrier and increase the expression of a brain-derived neurotrophic factor (BDNF) in the hippocampus, which improves learning and memory. In addition, the neuroprotective effect of irisin has been verified in various disease models. Therefore, this review summarizes how irisin plays a neuroprotective role, including its signal pathway and mechanism. In addition, we will briefly discuss the therapeutic potential of irisin for neurological diseases.

The mechanism of action of the combination of Astragalus membranaceus and Ligusticum chuanxiong in the treatment of ischemic stroke based on network pharmacology and molecular docking

Since 1990, the incidence of stroke has been rising to become the second leading cause of death in the world, posing a huge burden and challenge to society and families. Astragalus membranaceus and Ligusticum chuanxiong (A&L) have been used as traditional Chinese medicine (TCM) prescriptions to treat and prevent the occurrence of ischemic stroke (IS), but their mechanism of action on the disease has not been fully elucidated. The main objective of this study was to reveal the pharmacological mechanism of A&L in the treatment of IS and to perform preliminary validation. The active ingredients of A&L were obtained from the systematic pharmacology platform of traditional Chinese medicine (TCMSP) database, whereas the genes of IS were obtained from 2 major databases, DrugBank and GeneCards. Cytoscape_v3.8.2 was used to construct the TCM-active ingredient and TCM-active ingredient-cross-target-disease relationship maps, and the MCODE plug-in was used to obtain the core genes, whereas the protein-protein interaction maps were obtained from the STRING database. The results of gene ontology and Kyoto encyclopedia of genes and genomes enrichment were obtained using the Hiplot online tool, and the small molecules in the relevant signalling pathways were verified by molecular docking using AutoDock. A&L contained a total of 26 eligible active ingredients, sharing 161 common targets with IS. A total of 58 core genes with 1326 edges were obtained using the MCODE plug-in. Gene ontology and Kyoto encyclopedia of genes and genomes enrichment results showed association with interleukin-17 signaling pathway, lipid and atherosclerosis, tumor necrosis factor signaling pathway, and Toll-like receptor signaling pathway, which mainly mediates the development of inflammatory responses. Furthermore, molecular docking was conducted and most of the components were found to have good binding to the receptors. This study demonstrates that A&L can be used to treat IS by controlling the inflammatory response through multiple targets and multiple pathways, and provides a reference for subsequent trials.

Irisin is an Effector Molecule in Exercise Rehabilitation Following Myocardial Infarction (Review)

Background: Regular exercise is an effective non-pharmacological therapy for treatment and prevention of cardiovascular disease (CVD). The therapeutic benefits of exercise are mediated partly through improved vascular and increase in metabolic health. Release of exercise-responsive myokines, including irisin, is associated with beneficial effects of exercise in CVD patients.

Observations: The present review provides an overview of the role of exercise in cardiac rehabilitation of patients with myocardial infarction (MI). Further, the role of irisin as a motion-responsive molecule in improving vascular and metabolic health is explored. Possible mechanism of cardioprotective effect of irisin-mediated exercise on myocardial infarction are also summarized in this review.

Conclusion and significance of the review: Irisin is associated with reduced inflammation, antioxidant properties, and anti-apoptotic effect, implying that it is a potential key mediator of the beneficial effects of exercise on vascular and metabolic health. The findings show that irisin is a promising therapeutic target for treatment of patients with cardiovascular disease, particularly post-MI. Further research should be conducted to elucidate the potential mechanisms of cardioprotective effects of irisin and explored whether irisin induced by exercise exerts rehabilitation effects post-MI.

Serum Irisin Levels and Its Relationship with Spasticity Severity in Chronic Stroke Patients

Objective Irisin is a myokine released from muscles by exercise and it has been shown to be a prognostic indicator in acute stroke patients. However, irisin's relationship with the chronic phase of stroke and spasticity has not been studied yet. We aimed to determine the serum level of irisin to examine its relationship with the functional status and severity of spasticity in patients with chronic stroke, and to compare these with healthy controls.

Materials and Methods A total of 70 (35 chronic stroke and 35 control patients) patients were included in the study. The blood serum irisin levels of the patients and the controls were evaluated using enzyme-linked immunosorbent assay method, their functional status was evaluated with the modified Rankin scale (mRS), and spasticity severity using the modified Ashworth scale (MAS).

Results The mean serum irisin levels of the stroke and the control groups were 6.20 ± 2.2 and 5.45 ± 2.3, respectively, and there was no statistically significant difference (p > 0.05). No significant correlation was found between the serum level of irisin and the severity of spasticity and functional status, assessed by the mRS in stroke patients.

Conclusion These results showed that irisin levels in chronic stroke patients were similar to controls, and there was no relationship between the severity of spasticity and functional status and irisin level.

Plasma levels of BDNF and EGF are reduced in acute stroke patients

Stroke affects almost 14 million people worldwide each year. It is the second leading cause of death and a major cause of acquired disability. The degree of initial impairment in cognitive and motor functions greatly affects the recovery, but idiosyncratic factors also contribute. These are largely unidentified, which contributes to making accurate prediction of recovery challenging. Release of soluble regulators of neurotoxicity, neuroprotection and repair are presumably essential. Here we measured plasma levels of known regulators of neuroprotection and repair in patients with mild acute ischemic stroke and compared them to the plasma levels in healthy age and gender matched controls. We found that the levels of BDNF and EGF were substantially lower in stroke patients than in healthy controls, while the levels of bFGF and irisin did not differ between the groups. The lower levels of growth factors highlight that during the acute phase of stroke, there is a mismatch between the need for neuroprotection and repair, and the brain's ability to induce these processes. Large individual differences in growth factor levels were seen among the stroke patients, but whether these can be used as predictors of long-term prognosis remains to be investigated.

Peroxisome proliferator-activated receptor-γ ameliorates neuronal ferroptosis after traumatic brain injury in mice by inhibiting cyclooxygenase-2

Among the multiple kinds of neuronal cell death triggered by traumatic brain injury (TBI), ferroptosis, an iron-dependent lipid peroxidative regulatory cell death, has a critical role. Peroxisome proliferator-activated receptor-γ (PPARγ) is a nuclear transcription factor that regulates lipid metabolism and suppresses neuronal inflammation. However, the role of PPARγ in neuronal ferroptosis induced by TBI remains unclear. Here, we investigated the regulatory effect of PPARγ on neuronal ferroptosis in a weight-drop TBI model in vivo and an RAS-selective lethal 3 (RSL3)-activated ferroptotic neuronal model in vitro. PPARγ was mainly localized in the nucleus of neurons and was decreased in both the in vivo TBI model and the in vitro ferroptotic neuronal model. The addition of a specific agonist, pioglitazone, activated PPARγ, which protected neuronal function post-TBI in vivo and increased the viability of ferroptotic neurons in vitro. Further investigation suggested that PPARγ probably attenuates neuronal ferroptosis by downregulating cyclooxygenase-2 (COX2) protein expression levels in vivo and in vitro. This study revealed the relationship among PPARγ, ferroptosis and TBI and identified a potential target for comprehensive TBI treatment.

Effects of the FNDC5/Irisin on Elderly Dementia and Cognitive Impairment

Population aging is an inevitable problem nowadays, and the elderly are going through a lot of geriatric symptoms, especially cognitive impairment. Irisin, an exercise-stimulating cleaved product from transmembrane fibronectin type III domain-containing protein 5 (FNDC5), has been linked with favorable effects on many metabolic diseases. Recently, mounting studies also highlighted the neuroprotective effects of irisin on dementia. The current evidence remains uncertain, and few clinical trials have been undertaken to limit its clinical practice. Therefore, we provided an overview of current scientific knowledge focusing on the preventive mechanisms of irisin on senile cognitive decline and dementia, in terms of the possible connections between irisin and neurogenesis, neuroinflammation, oxidative stress, and dementia-related diseases. This study summarized the recent advances and ongoing studies, aiming to provide a better scope into the effectiveness of irisin on dementia progression, as well as a mediator of muscle brain cross talk to provide theoretical support for exercise therapy for patients with dementia. Whether irisin is a diagnostic or prognostic factor for dementia needs more researches.

Molecular mechanisms of developmental pathways in neurological disorders: a pharmacological and therapeutic review

Developmental signalling pathways such as Wnt/β-catenin, Notch and Sonic hedgehog play a central role in nearly all the stages of neuronal development. The term 'embryonic' might appear to be a misnomer to several people because these pathways are functional during the early stages of embryonic development and adulthood, albeit to a certain degree. Therefore, any aberration in these pathways or their associated components may contribute towards a detrimental outcome in the form of neurological disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and stroke. In the last decade, researchers have extensively studied these pathways to decipher disease-related interactions, which can be used as therapeutic targets to improve outcomes in patients with neurological abnormalities. However, a lot remains to be understood in this domain. Nevertheless, there is strong evidence supporting the fact that embryonic signalling is indeed a crucial mechanism as is manifested by its role in driving memory loss, motor impairments and many other processes after brain trauma. In this review, we explore the key roles of three embryonic pathways in modulating a range of homeostatic processes such as maintaining blood-brain barrier integrity, mitochondrial dynamics and neuroinflammation. In addition, we extensively investigated the effect of these pathways in driving the pathophysiology of a range of disorders such as Alzheimer's, Parkinson's and diabetic neuropathy. The concluding section of the review is dedicated to neurotherapeutics, wherein we identify and list a range of biological molecules and compounds that have shown enormous potential in improving prognosis in patients with these disorders.

FNDC5/Irisin: Physiology and Pathophysiology

A sedentary lifestyle or lack of physical activity increases the risk of different diseases, including obesity, diabetes, heart diseases, certain types of cancers, and some neurological diseases. Physical exercise helps improve quality of life and reduces the risk of many diseases. Irisin, a hormone induced by exercise, is a fragmented product of FNDC5 (a cell membrane protein) and acts as a linkage between muscles and other tissues. Over the past decade, it has become clear that irisin is a molecular mimic of exercise and shows various beneficial effects, such as browning of adipocytes, modulation of metabolic processes, regulation of bone metabolism, and functioning of the nervous system. Irisin has a role in carcinogenesis; numerous studies have shown its impact on migration, invasion, and proliferation of cancer cells. The receptor of irisin is not completely known; however, in some tissues it probably acts via a specific class of integrin receptors. Here, we review research from the past decade that has identified irisin as a potential therapeutic agent in the prevention or treatment of various metabolic-related and other diseases. This article delineates structural and biochemical aspects of irisin and provides an insight into the role of irisin in different pathological conditions.

Irisin: A Promising Target for Ischemia-Reperfusion Injury Therapy

Ischemia-reperfusion injury (IRI) is defined as the total combined damage that occurs during a period of ischemia and following the recovery of blood flow. Oxidative stress, mitochondrial dysfunction, and an inflammatory response are factors contributing to IRI-related damage that can each result in cell death. Irisin is a polypeptide that is proteolytically cleaved from the extracellular domain of fibronectin type III domain-containing protein 5 (FNDC5). Irisin acts as a myokine that potentially mediates beneficial effects of exercise by reducing oxidative stress, improving mitochondrial fitness, and suppressing inflammation. The existing literature also suggests a possible link between irisin and IRI, involving mechanisms similar to those associated with exercise. This article will review the pathogenesis of IRI and the potential benefits and current limitations of irisin as a therapeutic strategy for IRI, while highlighting the mechanistic correlations between irisin and IRI.

Irisin Rescues Blood-Brain Barrier Permeability following Traumatic Brain Injury and Contributes to the Neuroprotection of Exercise in Traumatic Brain Injury

Traumatic brain injury (TBI) has a high incidence, mortality, and morbidity all over the world. One important reason for its poor clinical prognosis is brain edema caused by blood-brain barrier (BBB) dysfunction after TBI. The mechanism may be related to the disorder of mitochondrial morphology and function of neurons in damaged brain tissue, the decrease of uncoupling protein 2 (UCP2) activity, and the increase of inflammatory reaction and oxidative stress. In this study, we aimed to investigate the effects of exogenous irisin on BBB dysfunction after TBI and its role in the neuroprotective effects of endurance exercise (EE) in mice. The concentrations of irisin in cerebrospinal fluid (CSF) and plasma of patients with mild to severe TBI were measured by ELISA. Then, male C57BL/6J mice and UCP2 knockout mice with C57BL/6J background were used to establish the TBI model. The BBB structure and permeability were examined by transmission electron microscopy and Evans blue extravasation, respectively. The protein expressions of irisin, occludin, claudin-5, zonula occludens-1 (ZO-1), nuclear factor E2-related factor 2(Nrf2), quinine oxidoreductase (NQO-1), hemeoxygenase-1 (HO-1), cytochrome C (Cyt-C), cytochrome C oxidase (COX IV), BCL2-associated X protein (Bax), cleaved caspase-3, and UCP2 were detected by western blot. The production of reactive oxygen species (ROS) was evaluated by the dihydroethidium (DHE) staining. The levels of inflammatory factors were detected by ELISA. In this study, we found that the CSF irisin levels were positively correlated with the severity of disease in patients with TBI and both EE and exogenous irisin could reduce BBB damage in a mouse model of TBI. In addition, we used UCP2-/- mice and further found that irisin could improve the dysfunction of BBB after TBI by promoting the expression of UCP2 on the mitochondrial membrane of neurons, reducing the damage of mitochondrial structure and function, thus alleviating the inflammatory response and oxidative stress. In conclusion, the results of this study suggested that irisin might alleviate brain edema after TBI by promoting the expression of UCP2 on the mitochondrial membrane of neurons and contribute to the neuroprotection of EE against TBI.

Exercise-Linked Irisin Prevents Mortality and Enhances Cognition in a Mice Model of Cerebral Ischemia by Regulating Klotho Expression

Irisin, which can be released in the hippocampus after physical exercise, is demonstrated to have beneficial effects on neurovascular diseases. This study investigated the impact of exercise linked-irisin on mortality and cognition in a mice model of cerebral ischemia and further explored its underlying mechanism. The cerebrospinal concentrations of irisin and klotho from ischemic stroke patients were measured with an enzyme-linked immunosorbent assay (ELISA). The cognitive function of mice was evaluated by a series of behavioural experiments. The expressions of klotho, MnSOD, and FOXO3a in the hippocampus of mice were detected by Western blot. Superoxide production in the brain tissue of mice was evaluated with the dihydroethidium (DHE) dying. The results demonstrated that stroke patients showed a positive correlation between their CSF irisin concentration and klotho concentration. In addition, when mice subjected to cerebral ischemia, their cognitive function was impaired, the protein expressions of klotho, MnSOD, and FOXO3a downregulated, and the production of reactive oxygen species (ROS) increased compared with the sham group. After pretreatment with exogenous irisin, improved cognitive impairment, upregulated protein expressions of klotho, MnSOD, and FOXO3a, and reduced ROS generation were observed in mice with MCAO. However, the neuroprotective effects of irisin compromised with the evidence of severe cognitive impairment, decreased protein expressions of MnSOD and FOXO3a, and increased ROS production in klotho knockout mice. Thus, our results indicated that exercise-linked irisin could prevent mortality and improve cognitive impairment after cerebral ischemia by regulating klotho expression.

Exercise Factors Released by the Liver, Muscle, and Bones Have Promising Therapeutic Potential for Stroke

Stroke is one of the leading causes of death and disability in the world. Stroke not only affects the patients, but also their families who serve as the primary caregivers. Discovering novel therapeutic targets for stroke is crucial both from a quality of life perspective as well as from a health economic perspective. Exercise is known to promote neuroprotection in the context of stroke. Indeed, exercise induces the release of blood-borne factors that promote positive effects on the brain. Identifying the factors that mediate the positive effects of exercise after ischemic stroke is crucial for the quest for novel therapies. This approach will yield endogenous molecules that normally cross the blood brain barrier (BBB) and that can mimic the effects of exercise. In this minireview, we will discuss the roles of exercise factors released by the liver such as beta-hydroxybutyrate (DBHB), by the muscle such as lactate and irisin and by the bones such as osteocalcin. We will also address their therapeutic potential in the context of ischemic stroke.

Mesenchymal Stem Cell Transplantation for Ischemic Diseases: Mechanisms and Challenges

Ischemic diseases are conditions associated with the restriction or blockage of blood supply to specific tissues. These conditions can cause moderate to severe complications in patients, and can lead to permanent disabilities. Since they are blood vessel-related diseases, ischemic diseases are usually treated with endothelial cells or endothelial progenitor cells that can regenerate new blood vessels. However, in recent years, mesenchymal stem cells (MSCs) have shown potent bioeffects on angiogenesis, thus playing a role in blood regeneration. Indeed, MSCs can trigger angiogenesis at ischemic sites by several mechanisms related to their trans-differentiation potential. These mechanisms include inhibition of apoptosis, stimulation of angiogenesis via angiogenic growth factors, and regulation of immune responses, as well as regulation of scarring to suppress blood vessel regeneration when needed. However, preclinical and clinical trials of MSC transplantation in ischemic diseases have shown some limitations in terms of treatment efficacy. Such studies have emphasized the current challenges of MSC-based therapies. Treatment efficacy could be enhanced if the limitations were better understood and potentially resolved. This review will summarize some of the strategies by which MSCs have been utilized for ischemic disease treatment, and will highlight some challenges of those applications as well as suggesting some strategies to improve treatment efficacy.