Isorhapontigenin ameliorates cerebral ischemia/reperfusion injury via modulating Kinase Cε/Nrf2/HO-1 signaling pathway

Nanoparticles transfected with plasmid-encoded lncRNA-OIP5-AS1 inhibit renal ischemia-reperfusion injury in mice via the miR-410-3p/Nrf2 axis

Nanostructures composed of liposomes and polydopamine (PDA) have demonstrated efficacy as carriers for delivering plasmids, effectively alleviating renal cell carcinoma. However, their role in acute kidney injury (AKI) remains unclear. This study aimed to investigate the effects of the plasmid-encoded lncRNA-OIP5-AS1@PDA nanoparticles (POP-NPs) on renal ischemia/reperfusion (RI/R) injury and explore the underlying mechanisms. RI/R or OGD/R models were established in mice and HK-2 cells, respectively. In vivo, vector or POP-NPs were administered (10 nmol, IV) 48 h after RI/R treatment. In the RI/R mouse model, the OIP5-AS1 and Nrf2/HO-1 expressions were down-regulated, while miR-410-3p expression was upregulated. POP-NPs treatment effectively reversed RI/R-induced renal tissue injury, restoring altered levels of blood urea nitrogen, creatinine, malondialdehyde, inflammatory factors (IL-8, IL-6, TNF-α), ROS, apoptosis, miR-410-3p, as well as the suppressed expression of SOD and Nrf2/HO-1 in the model mice. Similar results were obtained in cell models treated with POP-NPs. Additionally, miR-410-3p mimics could reverse the effects of POP-NPs on cellular models, partially counteracted by Nrf2 agonists. The binding relationship between OIP5-AS1 and miR-410-3p, alongside miR-410-3p and Nrf2, has been substantiated by dual-luciferase reporter and RNA pull-down assays. The study revealed that POP-NPs can attenuate RI/R-induced injury through miR-410-3p/Nrf2 axis. These findings lay the groundwork for future targeted therapeutic approaches utilizing nanoparticles for RI/R-induced AKI.

The protective effect of Astaxanthin on scopolamine - induced Alzheimer's model in mice

OBJECTIVES

To investigate the fundamental mechanisms of the neuroprotective impact of Astaxanthin (AST) in a mouse model of Alzheimer's disease (AD) induced by scopolamine.

METHODS

This research constituted an in vivo animal study encompassing 36 adult male mice, divided into 6 groups: Control, 100 mg/kg AST, 2 mg/kg scopolamine (AD group), 100 mg/kg AST+2 mg/kg scopolamine, 3 mg/kg galantamine+2 mg/kg scopolamine, and 100 mg/kg AST+3 mg/kg galantamine+2 mg/kg scopolamine. After 14 days, the mice's short-term memory, hippocampus tissue, oxidative and inflammatory markers were evaluated.

RESULTS

The AST demonstrated a beneficial influence on short-term memory and a reduction in acetylcholinesterase activity in the brain. It exhibited neuroprotective and anti-amyloidogenic properties, significantly decreased pro-inflammatory markers and oxidative stress, and reversed the decline of the Akt-1 and phosphorylated Akt pathway, a crucial regulator of abnormal tau. Furthermore, AST enhanced the effect of galantamine in reducing inflammation and oxidative stress.

CONCLUSION

The findings indicate that AST may offer therapeutic benefits against cognitive dysfunction in AD. This is attributed to its ability to reduce oxidative stress, control neuroinflammation, and enhance Akt-1 and pAkt levels, thereby underscoring its potential in AD treatment strategies.

Urolithin B Attenuates Cerebral Ischemia-reperfusion Injury by Modulating Nrf2-regulated Anti-oxidation in Rats

Ischemia-reperfusion (IR) induces a wide range of irreversible injuries. Cerebral IR injury (IRI) refers to additional brain tissue damage that occurs after blood flow is restored following cerebral ischemia. Currently, no established methods exist for treating IRI. Oxidative stress is recognized as a primary mechanism initiating IRI and a crucial focal target for its treatment. Urolithin B, a metabolite derived from ellagitannins, antioxidant polyphenols, has demonstrated protective effects against oxidative stress in various disease conditions. However, the precise mechanism underlying UB's effect on IRI remains unclear. In our current investigation, we assessed UB's ability to mitigate neurological functional impairment induced by IR using a neurological deficit score. Additionally, we examined cerebral infarction following UB administration through TTC staining and neuron Nissl staining. UB's inhibition of neuronal apoptosis was demonstrated through the TUNEL assay and Caspase-3 measurement. Additionally, we examined UB's effect on oxidative stress levels by analyzing malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity, and immunohistochemistry analysis of inducible nitric oxide synthase (iNOS) and 8-hydroxyl-2'-deoxyguanosine (8-OHdG). Notably, UB demonstrated a reduction in oxidative stress levels. Mechanistically, UB was found to stimulate the Nrf2/HO-1 signaling pathway, as evidenced by the significant reduction in UB's neuroprotective effects upon administration of ATRA, an Nrf2 inhibitor. In summary, UB effectively inhibits oxidative stress induced by IR through the activation of the Nrf2/HO-1 signaling pathway. These findings suggest that UB holds promise as a therapeutic agent for the treatment of IRI.

Antiproliferative Effects in Colorectal Cancer and Stabilisation in Cyclodextrins of the Phytoalexin Isorhapontigenin

Isorhapontigenin has been proposed as a better alternative for oral administration than the famous resveratrol, as it shares many biological activities, but with a structure that could make its delivery easier. Although this hydrophobic structure could enhance bioavailability, it could also be a disadvantage in the development of products. In this research, we study the antiproliferative activity of this stilbene against colorectal cancer and overcome its limitations through molecular encapsulation in cyclodextrins. The cytotoxic activity against human colorectal cancer cells of isorhapontigenin was similar to that of resveratrol or piceatannol, supporting its use as a bioactive alternative. The study of the encapsulation through fluorescence spectroscopy and molecular docking revealed that the complexation satisfies a 1:1 stoichiometry and that HP-β-CD is the most suitable CD to encapsulate this stilbene. Through a spectrophotometric assay, it was observed that this CD could double the basal water solubility, exceeding the solubility of other hydroxylated stilbenes. The stability of these inclusion complexes was higher at a pH below 9 and refrigeration temperatures. Moreover, the use of CDs retained more than 78% of isorhapontigenin after storage for 12 weeks, compared to 15% in free form. Overall, these findings could help design novel formulations to better deliver isorhapontigenin.

Upregulation of CDGSH iron sulfur domain 2 attenuates cerebral ischemia/reperfusion injury

CDGSH iron sulfur domain 2 can inhibit ferroptosis, which has been associated with cerebral ischemia/reperfusion, in individuals with head and neck cancer. Therefore, CDGSH iron sulfur domain 2 may be implicated in cerebral ischemia/reperfusion injury. To validate this hypothesis in the present study, we established mouse models of occlusion of the middle cerebral artery and HT22 cell models of oxygen-glucose deprivation and reoxygenation to mimic cerebral ischemia/reperfusion injury in vivo and in vitro, respectively. We found remarkably decreased CDGSH iron sulfur domain 2 expression in the mouse brain tissue and HT22 cells. When we used adeno-associated virus and plasmid to up-regulate CDGSH iron sulfur domain 2 expression in the brain tissue and HT22 cell models separately, mouse neurological dysfunction was greatly improved; the cerebral infarct volume was reduced; the survival rate of HT22 cells was increased; HT22 cell injury was alleviated; the expression of ferroptosis-related glutathione peroxidase 4, cystine-glutamate antiporter, and glutathione was increased; the levels of malondialdehyde, iron ions, and the expression of transferrin receptor 1 were decreased; and the expression of nuclear-factor E2-related factor 2/heme oxygenase 1 was increased. Inhibition of CDGSH iron sulfur domain 2 upregulation via the nuclear-factor E2-related factor 2 inhibitor ML385 in oxygen-glucose deprived and reoxygenated HT22 cells blocked the neuroprotective effects of CDGSH iron sulfur domain 2 up-regulation and the activation of the nuclear-factor E2-related factor 2/heme oxygenase 1 pathway. Our data indicate that the up-regulation of CDGSH iron sulfur domain 2 can attenuate cerebral ischemia/reperfusion injury, thus providing theoretical support from the perspectives of cytology and experimental zoology for the use of this protein as a therapeutic target in patients with cerebral ischemia/reperfusion injury.

Development of sertraline analogues as potential anti-ischemic stroke agents

Ischemic stroke (IS) is harmful to human health and social development, and there is no medicine available at present. To find the hit compound for treating ischemic stroke, we screened 28 FDA approved nervous system drugs by using an in vitro OGD-induced stroke model. Notably, our in vitro and in vivo studies demonstrated that low-dose sertraline had good neuroprotective activities, while high-dose sertraline showed significant toxicity. Interestingly, the same high-dose sertraline in the control group did not exhibit any obvious toxic effect. Therefore, it is important to modify the structure of sertraline to improve the activity and reduce the toxicity. Stereoisomers of sertraline were first investigated to analyze the influence of stereochemistry on the neuroprotective activities, which showed no obvious difference. Then we evaluated the activity of our previously reported sertraline analogues and found that introducing amide or alkane groups to the amino moiety might be beneficial to enhance the activity and reduce the toxicity. Thus, 10 new analogues were designed, synthesized, and evaluated. Among them, compound OY-201 showed the best safety and neuroprotective activity in both in vitro and in vivo models. Moreover, it exhibited good blood-brain barrier (BBB) permeability, indicating its potential for the development of anti-ischemic stroke drugs.

Buyang Huanwu decoction alleviates oxidative injury of cerebral ischemia-reperfusion through PKCε/Nrf2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Ischemic stroke is a significant risk factor for human health, and Buyang Huanwu Decoction is a classical and famous Chinese formula for treating it, but without clear pharmacological mechanism.

AIM OF THE STUDY

The aim of this study was to investigate that the molecular mechanism of BYHWD activation of the PKCε/Nrf2 signaling pathway to attenuate cerebral ischemia-reperfusion (I/R) oxidative damage.

MATERIALS AND METHODS

The MCAO method was used to establish a brain I/R injury model in SD rats, and neurological deficits were evaluated by neurological function score. Neuronal damage was observed by Nissl staining and immunofluorescence detection of MAP2 expression. Oxidative damage was observed by ROS, SOD, GSH-PX, MDA, and 8-OHdG. Changes in mitochondrial membrane potential were detected by using the fluorescent probe JC-1. The Western blot analysis detected protein expression of PKCε, P-PKCε, total Nrf2, nuclear Nrf2, HO-1, and NQO1.

RESULTS

BYHWD significantly enhanced neural function, reduced neuronal damage, inhibited the production of ROS, decreased MDA and 8-OHdG levels, increased SOD and GSH-PX activity to reduce oxidative damage, and restored mitochondrial membrane potential. BYHWD and Nrf2 activator TBHQ increased total Nrf2, nucleus Nrf2 protein expression, and its downstream HO-1 and NQO1 proteins, and the administration of the Nrf2 inhibitor brusatol reduced the enhancing effect of BYHWD. Meanwhile, BYHWD increased the expression of PKCε and P-PKCε and the administration of the PKCε inhibitor εV1-2 reduced the effect of BYHWD in increasing the expression of PKCε, P-PKCε, nuclear Nrf2, and HO-1, as well as promoting the effect of Nrf2 translocation to the nucleus.

CONCLUSION

This study marks the first to demonstrate that BYHWD ameliorates oxidative damage and attenuates brain I/R injury by activating the PKCε/Nrf2/HO-1 pathway.

Nrf2 Regulates Oxidative Stress and Its Role in Cerebral Ischemic Stroke

Cerebral ischemic stroke is characterized by acute ischemia in a certain part of the brain, which leads to brain cells necrosis, apoptosis, ferroptosis, pyroptosis, etc. At present, there are limited effective clinical treatments for cerebral ischemic stroke, and the recovery of cerebral blood circulation will lead to cerebral ischemia-reperfusion injury (CIRI). Cerebral ischemic stroke involves many pathological processes such as oxidative stress, inflammation, and mitochondrial dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2), as one of the most critical antioxidant transcription factors in cells, can coordinate various cytoprotective factors to inhibit oxidative stress. Targeting Nrf2 is considered as a potential strategy to prevent and treat cerebral ischemia injury. During cerebral ischemia, Nrf2 participates in signaling pathways such as Keap1, PI3K/AKT, MAPK, NF-κB, and HO-1, and then alleviates cerebral ischemia injury or CIRI by inhibiting oxidative stress, anti-inflammation, maintaining mitochondrial homeostasis, protecting the blood-brain barrier, and inhibiting ferroptosis. In this review, we have discussed the structure of Nrf2, the mechanisms of Nrf2 in cerebral ischemic stroke, the related research on the treatment of cerebral ischemia through the Nrf2 signaling pathway in recent years, and expounded the important role and future potential of the Nrf2 pathway in cerebral ischemic stroke.

TGR5 overexpression mediated by the inhibition of transcription factor SOX9 protects against hypoxia-/reoxygenation-induced injury in hippocampal neurons by activating Nrf2/HO-1 signaling

Background

Cerebral ischemia/reperfusion (CI/R) injury is a destructive cerebrovascular disease associated with long-term disability and high mortality rates. TGR5 has been discovered in multiple human and animal tissues and to modulate a variety of physiological processes. The current study sought to reveal the function of TGR5 in CI/R injury and uncover the latent regulatory mechanism.

Methods

A hypoxia/reoxygenation (H/R) model was established in mouse hippocampal HT22 cells. The TGR5 expression in the H/R-treated HT22 cells was tested by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blots. After TGR5 was overexpressed, Cell Counting Kit-8 assays were used to estimate cell viability, and lactate dehydrogenase (LDH) release was assessed by a LDH assay kit. Cell apoptosis was measured by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling assays. Cytochrome c release was detected by immunofluorescence assays and western blots were used to analyze the protein levels of apoptosis-related factors. The oxidative stress levels were assessed by corresponding kits. Next, SOX9 expression in the H/R-treated HT22 cells was tested by RT-qPCR and western blots. The interaction between the TGR5 promoter and SOX9 was verified by luciferase reporter and chromatin immunoprecipitation assays. Subsequently, after the H/R-treated HT22 cells had been co-transfected with TGR5 overexpression and SOX9 overexpression plasmids, TGR5 expression was tested by RT-qPCR and western blots, and the above-mentioned functional experiments were repeated. Finally, the expression of Nrf2/HO-1 signaling-related proteins was examined by western blots.

Results

TGR5 expression was significantly decreased in the H/R-exposed HT22 cells. The elevation of TGR5 enhanced the viability, hindered the apoptosis, and alleviated the oxidative stress of the HT22 cells under H/R conditions. Additionally, SOX9 had a strong affinity with TGR5 promoter, and TGR5 was transcriptionally inhibited by SOX9. Further, SOX9 overexpression restored the protective role of TGR5 upregulation in H/R-induced HT22 cell injury. Additionally, TGR5 overexpression mediated by SOX9 inhibition activated Nrf2/HO-1 signaling.

Conclusions

TGR5 was transcriptionally inhibited by SOX9, and the overexpression of TGR5 played a protective role in CI/R injury.

Salvianolate ameliorates renal tubular injury through the Keap1/Nrf2/ARE pathway in mouse kidney ischemia-reperfusion injury

ETHNOPHARMACOLOGICAL RELEVANCE

Acute kidney injury (AKI) is a common clinical disease characterized by rapid loss of renal function. Salvianolate is a prescribed Chinese medicine derived from traditional Chinese medicine Salvia miltiorrhiza bunge that possesses many pharmacological effects, the active components extracted from Salvia miltiorrhiza bunge have been proved to protect ischemia-reperfusion (I/R)-AKI.

AIM OF THE STUDY

This study aims to validate the therapeutic effect of SAL on I/R-AKI, and explore its potential pharmacological mechanism.

MATERIALS AND METHODS

Mice were pretreated with/without salvianolate (10, 30, and 90 mg/kg) before renal ischemia-reperfusion operation. Serum creatinine, BUN, and H&E staining were performed to evaluate renal function. Immunofluorescence analysis was conducted to measure renal tubular injury including inflammatory factors and peroxide level. Apoptosis of the kidney tissues was determined by TUNEL assay. Keap1-Nrf2-ARE and apoptosis signaling pathways were measured by Western blot, RT-PCR, and YO-PRO-1 staining in kidneys or NRK52E cells.

RESULTS

Pretreatment with SAL effectively alleviated renal function and ameliorated epithelial tubular injury, oxidative stress, and inflammatory response. Furthermore, the mechanistic study demonstrated that the SAL exerts anti-apoptotic effects through activation of the Keap1-Nrf2-ARE signaling pathway in renal tubular cells.

CONCLUSION

These findings indicate the therapeutic benefit of salvianolate in the protection of renal injury from ischemia-reperfusion, and strengthen the evidence for the AKI treatment strategy by the anti-oxidative stress response, suggesting that SAL may be a potential agent for the treatment of AKI.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

Isorhapontigenin Modulates SOX9/TOLLIP Expression to Attenuate Cell Apoptosis and Oxidative Stress in Paraquat-Induced Acute Kidney Injury

Paraquat (PQ) is a widely used herbicide but can be lethal to humans. The kidney is vital for PQ elimination; therefore, explorations for therapeutic approaches for PQ-induced acute kidney injury (AKI) are of great significance. Here, the effects of a natural bioactive polyphenol isorhapontigenin (ISO) on PQ-AKI were investigated. In vitro experiments carried out in PQ-intoxicated rat renal tubular epithelial cells (NRK-52E) showed that ISO treatment inhibited PQ-induced cell apoptosis and oxidative stress, which was evidenced by the decreased proapoptotic proteins [cleaved caspase 3/9 and poly (ADP-ribose) polymerase (PARP)], the reduced oxidative stress indicators [reactive oxygen species (ROS), malondialdehyde (MDA), and lactate dehydrogenase (LDH) leakage], and the increased antioxidants [superoxide dismutase (SOD), nuclear factor E2-related factor 2 (NRF2), and oxygenase-1 (HO-1)]. Furthermore, 50 mg/kg ISO pretreatment before PQ administration significantly attenuated PQ-AKI in rats, as manifested by the improved renal tubule damage, the reduced serum and urine markers of kidney injury, and the inhibited cell apoptosis and oxidative stress in the renal cortex. Furthermore, expression of sex-determining region Y box 9 (SOX9) and Toll-interacting protein (TOLLIP) in NRK-52E cells and the renal cortex was significantly upregulated after ISO treatment. Overexpression of SOX9 increased TOLLIP transcription and attenuated PQ-induced apoptosis and oxidative stress, whereas knockdown of SOX9 impaired the protective effects of ISO on NRK-52E cells against PQ toxicity. In conclusion, the present study demonstrated that ISO modulated SOX9/TOLLIP expression to attenuate cell apoptosis and oxidative stress in PQ-AKI, suggesting the potential of ISO in treating PQ-poisoned patients.

Beta-Boswellic Acid Protects Against Cerebral Ischemia/Reperfusion Injury via the Protein Kinase C Epsilon/Nuclear Factor Erythroid 2-like 2/Heme Oxygenase-1 Pathway

Ischemic strokes are associated with a high rate of disability and death globally. Cerebral ischemia/reperfusion (I/R) injury is a type of brain damage associated with oxidative stress after an ischemic stroke. Beta-boswellic acid (β-BA) reportedly exerts antioxidant and neuroprotective effects, but its role in cerebral I/R injury is unclear. The aim of this research was to investigate the neuroprotective effects, as well as the mechanisms of β-BA in cerebral I/R injury. In vivo experiments were conducted using a rat middle cerebral artery occlusion and reperfusion (MCAO/R) model, and in vitro experiments were performed using a rat neuronal oxygen-glucose deprivation and reoxygenation (OGD/R) model. Triphenyltetrazolium chloride staining, neurological function scores, terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling, hematoxylin and eosin staining, and antioxidant levels in the brain were used to assess the effects of β-BA. Flow cytometry was used to detect reactive oxygen species and apoptotic cells. Western blotting and immunofluorescence staining were used to measure protein levels. The results showed that β-BA markedly improved neurological deficits and decreased infarct volume and necrotic neurons in rats. The in vitro results showed that β-BA protected neurons against OGD/R-induced injury. Additionally, β-BA significantly increased the phosphorylation of protein kinase C epsilon (PRKCE) at S729, the translocation of nuclear factor erythroid 2-like 2 (NFE2L2), and expression of heme oxygenase-1 (HMOX1). This study demonstrates that β-BA exerts neuroprotective effects against cerebral I/R via the activation of the PRKCE/NFE2L2/HMOX1 pathway and is a potential therapeutic candidate for ischemic stroke.

Isorhapontigenin ameliorates cerebral ischemia/reperfusion injury via modulating Kinase Cε/Nrf2/HO-1 signaling pathway

BACKGROUND

Isorhapontigenin (ISO) has been shown to have antioxidant activity. This study aimed to investigate the antioxidant effects of ISO on cerebral ischemia/reperfusion (I/R) injury and its possible molecular mechanisms.

METHODS

Focal cerebral ischemia-reperfusion injury (MCAO/R) model and primary cortical neurons were established an oxygen-glucose deprivation (OGD / R) injury model. After 24 hr of reperfusion, the neurological deficits of the rats were analyzed and HE staining was performed, and the infarct volume was calculated by TTC staining. In addition, the reactive oxygen species (ROS) in rat brain tissue, the content of 4-Hydroxynonenal (4-HNE), and 8-hydroxy2deoxyguanosine (8-OHdG) were detected. Neuronal cell viability was determined by MTT assay. Western blot analysis was determined for protein expression.

RESULTS

ISO treatment significantly improved neurological scores, reduced infarct volume, necrotic neurons, ROS production, 4-HNE, and 8-OHdG levels. At the same time, ISO significantly increased the expression of Nrf2 and HO-1. The neuroprotective effects of ISO can be eliminated by knocking down Nrf2 and HO-1. In addition, knockdown of the PKCε blocked ISO-induced nuclear Nfr2, HO-1 expression.

CONCLUSION

ISO protected against oxidative damage induced by brain I/R, and its neuroprotective mechanism may be related to the PKCε/Nrf2/HO-1 pathway.