CPUY192018, a potent inhibitor of the Keap1-Nrf2 protein-protein interaction, alleviates renal inflammation in mice by restricting oxidative stress and NF-κB activation

Adenosine A2A Receptor Antagonist Sch58261 Improves the Cognitive Function in Alzheimer's Disease Model Mice Through Activation of Nrf2 via an Autophagy-Dependent Pathway

Aims: Adenosine, an important endogenous neuromodulator, contributes to a broad set of several neurodegenerative diseases. The adenosine A2A receptor (A2AR) is the most involved in neuropathological effects and plays an important role in the pathogenesis of Alzheimer's disease (AD). However, the effect of A2AR antagonist and the underlying mechanism in AD model mice remains unclear. Results: The amyloid beta (Aβ)1-42-induced mice AD models were used in this study. Several behavioral experiments were performed to evaluate the improvement of AD mice treated with A2AR antagonist. For mechanism analysis, autophagy-related proteins, Kelch-like ECH-associated protein1 (Keap1)-nuclear factor erythroid-derived factor 2-related factor (Nrf2) pathway activation, and synaptic function were studied using Western blot, immunofluorescence, immunohistochemistry, transmission electron microscope, real-time quantitative PCR, and patch clamp. Pharmacological blockade of adenosine A2AR by SCH58261 (SCH) ameliorated cognitive deficits and decreased expression levels of several AD biomarkers, including Aβ and hyperphosphorylation of Tau. Moreover, SCH activated the Nrf2 pathway through autophagy mediated Keap1 degradation, resulting in the improvement of neuron autophagy dysfunction, synaptic plasticity, and synaptic transmission. Innovation: Our data clarified that the SCH (an antagonist of A2AR) could increase the level of autophagy, promote the ability of antioxidative stress by the activation of Keap1-Nrf2 pathway, and improve the synaptic function in Aβ1-42-induced AD mice or cell model, which provided a potential therapeutic strategy for AD. Conclusion: A2AR antagonism represents a promising strategy for the anti-AD agent development through autophagy-dependent pathway.

Bivalent inhibitors of the BTB E3 ligase KEAP1 enable instant NRF2 activation to suppress acute inflammatory response

Most BTB-containing E3 ligases homodimerize to recognize a single substrate by engaging multiple degrons, represented by E3 ligase KEAP1 dimer and its substrate NRF2. Inactivating KEAP1 to hinder ubiquitination-dependent NRF2 degradation activates NRF2. While various KEAP1 inhibitors have been reported, all reported inhibitors bind to KEAP1 in a monovalent fashion and activate NRF2 in a lagging manner. Herein, we report a unique bivalent KEAP1 inhibitor, biKEAP1 (3), that engages cellular KEAP1 dimer to directly release sequestered NRF2 protein, leading to an instant NRF2 activation. 3 promotes the nuclear translocation of NRF2, directly suppressing proinflammatory cytokine transcription. Data from in vivo experiments showed that 3, with unprecedented potency, reduced acute inflammatory burden in several acute inflammation models in a timely manner. Our findings demonstrate that the bivalent KEAP1 inhibitor can directly enable sequestered substrate NRF2 to suppress inflammatory transcription response and dampen various acute inflammation injuries.

Mechanism of Porphyra Yezoensis Polysaccharides in Inhibiting Hyperoxalate-Induced Renal Injury and Crystal Deposition

Oxidative damage to the kidneys is a primary factor in the occurrence of kidney stones. This study explores the inhibitory effect of Porphyra yezoensis polysaccharides (PYP) on oxalate-induced renal injury by detecting levels of oxidative damage, expression of adhesion molecules, and damage to intracellular organelles and revealed the molecular mechanism by molecular biology methods. Additionally, we validated the role of PYP in vivo using a crystallization model of hyperoxalate-induced rats. PYP effectively scavenged the overproduction of reactive oxygen species (ROS) in HK-2 cells, inhibited the adhesion of calcium oxalate (CaOx) crystals on the cell surface, unblocked the cell cycle, restored the depolarization of the mitochondrial membrane potential, and inhibited cell death. PYP upregulated the expression of antioxidant proteins, including Nrf2, HO-1, SOD, and CAT, while decreasing the expression of Keap-1, thereby activating the Keap1/Nrf2 signaling pathway. PYP inhibited CaOx deposition in renal tubules in the rat crystallization model, significantly reduced high oxalate-induced renal injury, decreased the levels of the cell surface adhesion proteins, improved renal function in rats, and ultimately inhibited the formation of kidney stones. Therefore, PYP, which has crystallization inhibition and antioxidant properties, may be a therapeutic option for the treatment of kidney stones.

Potential for the development of Taraxacum mongolicum aqueous extract as a phytogenic feed additive for poultry

Introduction

Taraxacum mongolicum (TM) is a kind of medicinal and edible homologous plant which is included in the catalogue of feed raw materials in China. It is rich in polyphenols, flavonoids, polysaccharides and other active substances, and shows many benefits to livestock, poultry and aquatic products. The study aimed to assess the potential of TM aqueous extract (TMAE) as a substitute for poultry AGPs.

Methods

A total of 240 one-day-old Arbor Acker broilers were randomly assigned to four groups and fed a basal diet (Con) supplemented with 500, 1000, and 2000 mg/kg TMAE (Low, Medium, and High groups). The growth performance of the broilers was measured on day 21 and day 42. At the end of the trial, the researchers measured slaughter performance and collected serum, liver, spleen, ileum, and intestinal contents to investigate the effects of TMAE on serum biochemistry, antioxidant capacity, immune function, organ coefficient, intestinal morphology, flora composition, and short-chain fatty acids (SCFAs).

Results

The results showed that broilers treated with TMAE had a significantly higher average daily gain from 22 to 42 days old compared to the Con group. Various doses of TMAE resulted in different levels of improvement in serum chemistry. High doses increased serum alkaline phosphatase and decreased creatinine. TMAE also increased the antioxidant capacity of serum, liver, and ileum in broilers. Additionally, middle and high doses of TMAE enhanced the innate immune function of the liver (IL-10) and ileum (Occludin) in broilers. Compared to the control group, the TMAE treatment group exhibited an increase in the ratio of villi length to villi crypt in the duodenum. TMAE increased the abundance of beneficial bacteria, such as Alistipes and Lactobacillus, while reducing the accumulation of harmful bacteria, such as Colidextracter and Sellimonas. The cecum's SCFAs content increased with a medium dose of TMAE. Supplementing broiler diets with TMAE at varying doses enhanced growth performance and overall health. The most significant benefits were observed at a dose of 1000 mg/kg, including improved serum biochemical parameters, intestinal morphology, antioxidant capacity of the liver and ileum, immune function of the liver and ileum, and increased SCFAs content. Lactobacillus aviarius, norank_f_norank_o__Clostridia_UCG-014, and Flavonifractor are potentially dominant members of the intestinal microflora.

Conclusion

In conclusion, TMAE is a promising poultry feed additive and 1000 mg/kg is an effective reference dose.

Azilsartan improves urinary albumin excretion in hypertension mice

Hypertension is one of the most important risk factors for chronic kidney diseases, leading to hypertensive nephrosclerosis, including excessive albuminuria. Azilsartan, an angiotensin II type 1 receptor blocker, has been widely used for the treatment of hypertension. However, the effects of Azilsartan on urinary albumin excretion in hypertension haven't been reported before. In this study, we investigated whether Azilsartan possesses a beneficial property against albuminuria in mice treated with angiotensin II and a high-salt diet (ANG/HS). Compared to the control group, the ANG/HS group had higher blood pressure, oxidative stress, and inflammatory response, all of which were rescued by Azilsartan dose-dependently. Importantly, the ANG/HS-induced increase in urinary albumin excretion and decrease in the expression of occludin were reversed by Azilsartan. Additionally, it was shown that increased fluorescence intensity of FITC-dextran, declined trans-endothelial electrical resistance (TEER) values, and reduction of occludin and krüppel-like factor 2 (KLF2) were observed in ANG/HS-treated human renal glomerular endothelial cells (HrGECs), then prevented by Azilsartan. Moreover, the regulatory effect of Azilsartan on endothelial monolayer permeability in ANG/HS-treated HrGECs was abolished by the knockdown of KLF2, indicating KLF2 is required for the effect of Azilsartan. We concluded that Azilsartan alleviated diabetic nephropathy-induced increase in Uterine artery embolization (UAE) mediated by the KLF2/occludin axis.

Nrf2 knockout attenuates the astragaloside IV therapeutic effect on kidney fibrosis from liver cancer by regulating pSmad3C/3L pathways

Fibrotic kidney injury from hepatocarcinogenesis seriously impacts treatment effect. Astragaloside IV (AS-IV), an extract of Astragalus membranaceus, has several pharmacological activities, which are useful in the treatment of edema and fibrosis. Nrf2/HO-1 is a key antioxidant stress pathway and help treatment of kidney injury. Smad3 phosphorylation is implicated in hepatocarcinogenesis. Our previous study clarified that Smad3 is differentially regulated by different phosphorylated forms of Smad3 on hepatocarcinogenesis. Therefore, we investigated the contribution of AS-IV on the therapy of kidney fibrosis from hepatocarcinogenesis. And the focus was on whether the phosphorylation of Smad3 and the regulation of Nrf2/HO-1 pathway were involved during AS-IV therapy and whether there is an effect of Nrf2 knockout on the phosphorylation of Smad3. We performed TGF-β1 stimulation on HK-2 cells and intervened with AS-IV. Furtherly, we investigated renal injury of AS-IV on Nrf2 knockout mice during hepatocarcinogenesis and its mechanism of action. On the one hand, in vitro results showed that AS-IV reduced the ROS and α-SMA expression of HK-2 by promoting the expression pSmad3C/p21 of and Nrf2/HO-1 and suppressed the expression of pSmad3L/PAI-1. On the other hand, the in vivo results of histopathological features, serological biomarkers, and oxidative damage indicators showed that Nrf2 knockout aggravated renal injury. Besides, Nrf2 deletion decreased the nephroprotective effect of AS-IV by suppressing the pSmad3C/p21 pathway and promoting the pSmad3L/PAI-1 pathway. The experimental results were as we suspected. And we identify for the first time that Nrf2 deficiency increases renal fibrosis from hepatocarcinogenesis and attenuates the therapeutic effects of AS-IV via regulating pSmad3C/3L signal pathway.

Oxidative stress-activated Nrf2 remitted polystyrene nanoplastic-induced mitochondrial damage and inflammatory response in HepG2 cells

Generated from plastics, microplastics (MPs) and nanoplastics (NPs) are difficult to completely degrade in the natural environment, which can accumulate in almost all lives. Liver is one of the main target organs. In this study, HepG2 and L02 cells were exposed to 0-50 μg/mL polystyrene (PS)-NPs to investigate the mechanism of mitochondrial damage and inflammation. The results showed mitochondria damage and inflammatory caused by NPs, and it can be inhibited by N-acetyl-L-cysteine (NAC). In addition, reactive oxygen species (ROS) activated nuclear factor erythroid-derived factor 2-related factor (Nrf2) pathway. Nrf2 siRNA exacerbated the injury, suggesting Nrf2 plays a protective role. Moreover, p62 siRNA increased ROS and mitochondrial damage by inhibiting Nrf2, but didn't affect the inflammation. In conclusion, Nrf2 was activated by ROS and played a protective role in PS-NPs-mediated hepatotoxicity. This study supplemented the data of liver injury caused by PS-NPs, providing a basis for the safe disposal of plastics.

Isoquercitrin attenuates the osteoclast-mediated bone loss in rheumatoid arthritis via the Nrf2/ROS/NF-κB pathway

An excess of osteoclastogenesis significantly contributes to the development of rheumatoid arthritis (RA). Activation of the nuclear factor erythroid-2 related factor 2 (Nrf2) and nuclear factor kappa B (NF-κB) ligand (RANKL)-induced reactive oxygen species (ROS)-to-NF-κB signaling cascade are important mechanisms regulating osteoclastogenesis; however, whether Nrf2 is involved in RANKL-induced NF-κB activation is controversial. Isoquercitrin, a natural flavonoid compound, has been shown to have Nrf2-dependent antioxidant effects inprevious studies. We sought to verify whether isoquercitrin could modulate RANKL-induced NF-κB activation by activating Nrf2, thereby affecting osteoclastogenesis. Tartrate-resistant acid phosphatase staining, F-actin ring staining and resorption pit assay suggested that isoquercitrin significantly inhibited osteoclastogenesis and osteolytic function. Mitosox staining showed that RANKL-induced ROS generation was significantly inhibited by isoquercitrin from day 3 of the osteoclast differentiation cycle. Quantitative real-time PCR, Western blot, and immunofluorescence indicated that isoquercitrin activated the Nrf2 signaling pathway and inhibited NF-κB expression. And when we used the Nrf2-specific inhibitor ML385, the inhibition of NF-κB by isoquercitrin disappeared. Moreover, we found that Nrf2 is not uninvolved in RANKL-induced NF-κB activation and may be related to the timing of ROS regulation. When we limited isoquercitrin administration to 2 days, Nrf2 remained activated and the inhibition of NF-κB disappeared. In vivo experiments suggested that isoquercitrin attenuated RA modeling-induced bone loss. Overall, isoquercitrin-activated Nrf2 blocked the RANKL-induced ROS-to-NF-κB signaling cascade response, thereby inhibiting osteoclastogenesis and bone loss. These findings provide new ideas for the treatment of RA.

Characterization and Exploration of the Neuroprotective Potential of Oat-Protein-Derived Peptides in PC12 Cells and Scopolamine-Treated Zebrafish

Neurodegenerative disorders pose a substantial risk to human health, and oxidative stress, cholinergic dysfunction, and inflammation are the major contributors. The purpose of this study was to explore the neuroprotective effects of oat protein hydrolysate (OPH) and identify peptides with neuroprotective potential. This study is the first to isolate and identify OPH peptides with neuroprotective potential, including DFVADHPFLF (DF-10), HGQNFPIL (HL-8), and RDFPITWPW (RW-9), by screening via peptidomes and molecular-docking simulations. These peptides showed positive effects on the activity of antioxidant enzymes and thus reduced oxidative stress through regulation of Nrf2-keap1/HO-1 gene expression in vitro and in vivo. The peptides also significantly ameliorated scopolamine-induced cognitive impairment in the zebrafish model. This improvement was correlated with mitigation of MDA levels, AChE activity, and levels of inflammatory cytokines in the brains of zebrafish. Furthermore, these peptides significantly upregulated the mRNA expression of Bdnf, Nrf2, and Erg1 in the brains of zebrafish with neurodegenerative disorders. Collectively, oat peptides have potential for use as active components in nutraceutical applications for the prevention of neurodegenerative diseases.

Advances in developing noncovalent small molecules targeting Keap1

Kelch-like ECH-associated protein 1 (Keap1) is a drug target for diseases involving oxidative stress and inflammation. There are three covalent Keap1-binding drugs on the market, but noncovalent compounds that inhibit the interaction between Keap1 and nuclear factor erythroid 2-related factor 2 (Nrf2) represent an attractive alternative. Both compound types prevent degradation of Nrf2, leading to the expression of antioxidant and antiinflammatory proteins. However, their off-target profiles differ as do their exact pharmacodynamic effects. Here, we discuss the opportunities and challenges of targeting Keap1 with covalent versus noncovalent inhibitors. We then provide a comprehensive overview of current noncovalent Keap1-Nrf2 inhibitors, with a focus on their pharmacological effects, to examine the therapeutic potential for this compound class.

MSC-Derived Exosomes Ameliorate Intervertebral Disc Degeneration By Regulating the Keap1/Nrf2 Axis

Bone marrow mesenchymal stem cell derived exosomes (BMSC-exos) are a crucial means of intercellular communication and can regulate a range of biological processes by reducing inflammation, decreasing apoptosis and promoting tissue repair. The process of intervertebral disc degeneration (IVDD) is accompanied by increased reactive oxygen species (ROS) because of a decrease in the expression of Nrf2, a critical transcription factor that resists excessive ROS. Our study demonstrated that BMSC-exos decreased ROS production by inhibiting Keap1 and promoting Nrf2 expression, attenuating the apoptosis, inflammation, and degeneration of nucelus pulposus (NP) cells. BMSC-exos promoted an increase in Nrf2 and nuclear translocation, while NF-κB expression was downregulated during this process. Additionally, the expression of antioxidative proteins was elevated after treatment with BMSC-exos. In vivo, we found more NP tissue retention in the BMSC-exos-treated group, along with more expression of Nrf2 and antioxidant-related proteins. Our findings demonstrated for the first time that BMSC-exos could restore the down-regulated antioxidant response system in degenerating NP cells by modulating the Keap1/Nrf2 axis. BMSC-exos could be used as an immediate ROS modulator in the treatment of intervertebral disc degeneration. When BMSC-exos were uptaken by NPCs, the expression of Keap1 decreased and this led to increased expression of Nrf2. Nuclear translocation of Nrf2 then promoted the synthesis of antioxidants against ROS and inhibited NF-kB signalling. Cellular inflammation, apoptosis, and ECM-related indicators were further reduced. Together, the process of IVDD was alleviated.

A new application of nano-selenium: rescue of CK2 and mitochondria from oxidative stress to prevent cardiac hypertrophy

Background: Excessive reactive oxygen species (ROS) and subsequent mitochondrial dysfunction are pivotal in initiating cardiac hypertrophy. To explore nano-selenium's (SeNP's) preventive potential against this condition, the authors evaluated chemically synthesized chitosan-SeNPs and biosynthesized Bacillus cereus YC-3-SeNPs in an angiotensin II (Ang II)-induced cardiac hypertrophy model. Methods: This investigation encompassed ROS measurement, mitochondrial membrane potential analysis, transmission electron microscopy, gene and protein expression analyses, protein carbonylation assays, serum antioxidant quantification and histological staining. Results: SeNPs effectively countered Ang II-induced cardiac hypertrophy by reducing ROS, restoring mitochondrial and protein kinase 2α (CK2-α) function, activating antioxidant pathways and enhancing serum antioxidant levels. Conclusion: This finding underscores SeNPs' role in attenuating Ang II-induced myocardial hypertrophy both in vitro and in vivo.

Fucoidan derived from Sargassum pallidum alleviates metabolism disorders associated with improvement of cardiac injury and oxidative stress in diabetic mice

Type 2 diabetes mellitus (T2DM) and its complications have become a serious global health epidemic. Cardiovascular complications have considered as a major cause of high mortality in diabetic patients. Fucoidans from brown algae have diverse medicinal activities, however, few studies reported pharmacological activity of Sargassum. pallidum fucoidan (Sp-Fuc). Therefore, the aim of this study was to investigate the effects of Sp-Fuc on diabetic symptoms and cardiac injury in spontaneous diabetic db/db mice. SP-Fuc at 200 mg/(kg/d) was administered intragastrically to db/db mice for 8 weeks, the effects on hyperlipidemia, hyperglycemia, insulin resistance, and cardiac damage, as well as oxidative stress, inflammation, Nrf2/ARE, and NF-κB signaling pathways, were investigated. Our data demonstrated that Sp-Fuc significantly (p < 0.05) decreased body weights, hyperlipidemia, and hyperglycemia in db/db mice, along with improved insulin sensitivity. Additionally, Sp-Fuc significantly (p < 0.05) alleviated cardiac dysfunction and pathological morphology of cardiac tissue. Sp-Fuc also significantly (p < 0.05) decreased lipid peroxidation, increased antioxidant function, as well as reduced cardiac inflammation, possibly through Nrf2/ARE and NF-κB signaling. Sp-Fuc can ameliorate the metabolism disorders of glucose and lipid in diabetic mice by activating Nrf2/ARE antioxidant signaling, simultaneously reducing cardiac redox imbalance and inflammatory damage. The present findings provide a perspective on the therapy strategy for T2DM and its complications.

The therapeutic potential of targeting regulated non-apoptotic cell death

Cell death is critical for the development and homeostasis of almost all multicellular organisms. Moreover, its dysregulation leads to diverse disease states. Historically, apoptosis was thought to be the major regulated cell death pathway, whereas necrosis was considered to be an unregulated form of cell death. However, research in recent decades has uncovered several forms of regulated necrosis that are implicated in degenerative diseases, inflammatory conditions and cancer. The growing insight into these regulated, non-apoptotic cell death pathways has opened new avenues for therapeutic targeting. Here, we describe the regulatory pathways of necroptosis, pyroptosis, parthanatos, ferroptosis, cuproptosis, lysozincrosis and disulfidptosis. We discuss small-molecule inhibitors of the pathways and prospects for future drug discovery. Together, the complex mechanisms governing these pathways offer strategies to develop therapeutics that control non-apoptotic cell death.

Licochalcone A plays dual antiviral roles by inhibiting RSV and protecting against host damage

Respiratory syncytial virus (RSV) causes lower respiratory tract diseases and bronchiolitis in children and elderly individuals. There are no effective drugs currently available to treat RSV infection. In this study, we report that Licochalcone A (LCA) can inhibit RSV replication and mitigate RSV-induced cell damage in vitro, and that LCA exerts a protective effect by reducing the viral titer and inflammation in the lungs of infected mice in vivo. We suggest that the mechanism of action occurs through pathways of antioxidant stress and inflammation. Further mechanistic results demonstrate that LCA can induce nuclear factor erythroid 2-related factor 2 (Nrf2) translocation into the nucleus, activate heme oxygenase 1 (HO-1), and inhibit reactive oxygen species-induced oxidative stress. LCA also works to reverse the decrease in I-kappa-B-alpha (IкBα) levels caused by RSV, which in turn inhibits inflammation through the associated nuclear factor kappa B and tumor necrosis factor-α signaling pathways. The combined action of the two cross-talking pathways protects hosts from RSV-induced damage. To conclude, our study is the first of its kind to establish evidence of LCA as a viable treatment for RSV infection.

Sulforaphane prevents LPS-induced inflammation by regulating the Nrf2-mediated autophagy pathway in goat mammary epithelial cells and a mouse model of mastitis

BACKGROUND

Mastitis not only deteriorates the composition or quality of milk, but also damages the health and productivity of dairy goats. Sulforaphane (SFN) is a phytochemical isothiocyanate compound with various pharmacological effects such as anti-oxidant and anti-inflammatory. However, the effect of SFN on mastitis has yet to be elucidated. This study aimed to explore the anti-oxidant and anti-inflammatory effects and potential molecular mechanisms of SFN in lipopolysaccharide (LPS)-induced primary goat mammary epithelial cells (GMECs) and a mouse model of mastitis.

RESULTS

In vitro, SFN downregulated the mRNA expression of inflammatory factors (tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6), inhibited the protein expression of inflammatory mediators (cyclooxygenase-2 (COX2), and inducible nitric oxide synthase (iNOS)) while suppressing nuclear factor kappa-B (NF-κB) activation in LPS-induced GMECs. Additionally, SFN exhibited an antioxidant effect by increasing Nrf2 expression and nuclear translocation, up-regulating antioxidant enzymes expression, and decreasing LPS-induced reactive oxygen species (ROS) production in GMECs. Furthermore, SFN pretreatment promoted the autophagy pathway, which was dependent on the increased Nrf2 level, and contributed significantly to the improved LPS-induced oxidative stress and inflammatory response. In vivo, SFN effectively alleviated histopathological lesions, suppressed the expression of inflammatory factors, enhanced immunohistochemistry staining of Nrf2, and amplified of LC3 puncta LPS-induced mastitis in mice. Mechanically, the in vitro and in vivo study showed that the anti-inflammatory and anti-oxidative stress effects of SFN were mediated by the Nrf2-mediated autophagy pathway in GMECs and a mouse model of mastitis.

CONCLUSIONS

These results indicate that the natural compound SFN has a preventive effect on LPS-induced inflammation through by regulating the Nrf2-mediated autophagy pathway in primary goat mammary epithelial cells and a mouse model of mastitis, which may improve prevention strategies for mastitis in dairy goats.

Proton Pump Inhibitors and Risk of Chronic Kidney Disease: Evidence from Observational Studies

Previous epidemiological studies have raised the concern that the use of proton pump inhibitors (PPIs) is associated with an increased risk of kidney diseases. To date, no comprehensive meta-analysis has been conducted to assess the association between PPIs and the risk of chronic kidney disease (CKD). Therefore, we conducted a systematic review and meta-analysis to address the association between PPIs and CKD. The primary search was conducted in the most popular databases, such as PubMed, Scopus, and Web of Science. All observational studies evaluated the risk of CKD among PPI users, and non-users were considered for inclusion. Two reviewers conducted data extraction and assessed the risk of bias. Random-effect models were used to calculate pooled effect sizes. A total of 6,829,905 participants from 10 observational studies were included. Compared with non-PPI use, PPI use was significantly associated with an increased risk of CKD (RR 1.72, 95% CI: 1.02–2.87, p = 0.03). This updated meta-analysis showed that PPI was significantly associated with an increased risk of CKD. Association was observed in the same among moderate-quality studies. Until further randomized control trials (RCTs) and biological studies confirm these results, PPI therapy should not stop patients with gastroesophageal reflux disease (GERD). However, caution should be used when prescribing to patients with high-risk kidney disease.

Chemical constituents from the stems and leaves of Amomum villosum Lour. and their anti-inflammatory and antioxidant activities

Amomum villosum Lour. is a medicinal and edible plant, whose medicinal parts are dried and mature fruits, and its stems and leaves are always treated as waste. HPLC-MS/MS analysis showed that the chemical components contained in the stems/leaves of A. villosum and those in fruits are quite different. To discover potential active ingredients from the stems/leaves of A. villosum, phytochemical evaluation of the stems/leaves of A. villosum was conducted to isolate and identify-four undescribed compounds (1, 2a, 2b, and 3) along with 41 known ones (4a, 4b, 5a, 5b, and 6-42). All isolated compounds were assessed for their anti-inflammatory and antioxidant activities. Among them, compounds 5b, 33, 34, and 38 exhibited anti-inflammatory activity, and compounds 1, 4a, 4b, 6, 7, 15, 33, 35, 37, and 41 showed antioxidant effects. Among them, the new compound 1 showed a significant antioxidant effect via activation of NRF2/HO-1 pathways. Therefore, the leaves and stems of A. villosum may be served as a potential medicine or dietary supplement for preventing and treating diseases resulting from inflammation and oxidative stress.

Icariside II preconditioning evokes robust neuroprotection against ischaemic stroke, by targeting Nrf2 and the OXPHOS/NF-κB/ferroptosis pathway

BACKGROUND AND PURPOSE

Astrocytic nuclear factor erythroid-derived 2-related factor 2 (Nrf2) is a potential therapeutic target of ischaemic preconditioning (IPC). Icariside II (ICS II) is a naturally occurring flavonoid derived from Herba Epimedii with Nrf2 induction potency. This study was designed to clarify if exposure to ICS II mimicks IPC neuroprotection and if Nrf2 from astrocytes contributes to ICS II preconditioning against ischaemic stroke.

EXPERIMENTAL APPROACH

Mice with transient middle cerebral artery occlusion (MCAO)-induced focal cerebral ischaemia and primary astrocytes challenged with oxygen-glucose deprivation (OGD) were used to explore the neuroprotective effect of ICS II preconditioning. Additionally, Nrf2-deficient mice were pretreated with ICS II to determine whether ICS II exerts its neuroprotection by activating Nrf2.

KEY RESULTS

ICS II pretreatment mitigated cerebral injury in the mouse model of ischaemic stroke along with improving long-term recovery. Furthermore, proteomics screening identified Nrf2 as a crucial gene evoked by ICS II treatment and required for the anti-oxidative effect and anti-inflammatory effect of ICS II. Also, ICS II directly bound to Nrf2 and reinforced the transcriptional activity of Nrf2 after MCAO. Moreover, ICS II pretreatment exerted cytoprotective effects on astrocyte cultures following lethal OGD exposure, by promoting Nrf2 nuclear translocation and activating the OXPHOS/NF-κB/ferroptosis axis, while neuroprotection was decreased in Nrf2-deficient mice and Nrf2 siRNA blocked effects of ICS II.

CONCLUSION AND IMPLICATIONS

ICS II preconditioning provides robust neuroprotection against ischaemic stroke via the astrocytic Nrf2-mediated OXPHOS/NF-κB/ferroptosis axis. Thus, ICS II could be a promising Nrf2 activator to treat ischaemic stroke.

Therapeutic effects of traditional Chinese medicine on gouty nephropathy: Based on NF-κB signalingpathways

As the final product of purine metabolism, excess serum uric acid (SUA) aggravates the process of some metabolic diseases. SUA causes renal tubule damage, interstitial fibrosis, and glomerular hardening, leading to gouty nephropathy (GN). A growing number of investigations have shown that NF-κB mediated inflammation and oxidative stress have been directly involved in the pathogenesis of GN. Traditional Chinese medicine's treatment methods of GN have amassed a wealth of treatment experience. In this review, we first describe the mechanism of NF-κB signaling pathways in GN. Subsequently, we highlight traditional Chinese medicine that can treat GN through NF-κB pathways. Finally, commenting on promising candidate targets of herbal medicine for GN treatment via suppressing NF-κB signaling pathways was summarized.

KEAP1-NRF2 protein-protein interaction inhibitors: Design, pharmacological properties and therapeutic potential

The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is considered the master regulator of the phase II antioxidant response. It controls a plethora of cytoprotective genes related to oxidative stress, inflammation, and protein homeostasis, among other processes. Activation of these pathways has been described in numerous pathologies including cancer, cardiovascular, respiratory, renal, digestive, metabolic, autoimmune, and neurodegenerative diseases. Considering the increasing interest of discovering novel NRF2 activators due to its clinical application, initial efforts were devoted to the development of electrophilic drugs able to induce NRF2 nuclear accumulation by targeting its natural repressor protein Kelch-like ECH-associated protein 1 (KEAP1) through covalent modifications on cysteine residues. However, off-target effects of these drugs prompted the development of an innovative strategy, the search of KEAP1-NRF2 protein-protein interaction (PPI) inhibitors. These innovative activators are proposed to target NRF2 in a more selective way, leading to potentially improved drugs with the application for a variety of diseases that are currently under investigation. In this review, we summarize known KEAP1-NRF2 PPI inhibitors to date and the bases of their design highlighting the most important features of their respective interactions. We also discuss the preclinical pharmacological properties described for the most promising compounds.

Dehydroeburicoic Acid, a Dual Inhibitor against Oxidative Stress in Alcoholic Liver Disease

Alcoholic liver disease (ALD) is a complicated disease which can lead to hepatocellular carcinoma; however, there is a lack of satisfactory therapeutics. Dehydroeburicoic acid (DEA) (1), a triterpenoid isolated from Antrodia cinnamomea, has been reported to act against ALD, but its mechanisms of action are still not clear. In this study, we report for the first time the use of DEA (1) as a dual inhibitor of the Keap1-Nrf2 protein-protein interaction (PPI) and GSK3β in an in vitro ALD cell model. DEA (1) engages Keap1 to disrupt the Keap1-Nrf2 PPI and inhibits GSK3β to restore Nrf2 activity in a Keap1-independent fashion. DEA (1) promotes Nrf2 nuclear translocation to activate downstream antioxidant genes. Importantly, DEA (1) restores the mitochondrial dysfunction induced by ethanol and generates antioxidant activity in the ALD cell model with minimal toxicity. We anticipate that DEA (1) could be a potential scaffold for the further development of clinical agents for treating ALD.

Naringenin attenuates inflammation, apoptosis, and ferroptosis in silver nanoparticle-induced lung injury through a mechanism associated with Nrf2/HO-1 axis: In vitro and in vivo studies

With the wide application of silver nanoparticles (AgNPs), their potential damage to human health needs to be investigated. Lung is one of the main target organs after inhalation of AgNPs. Naringenin has been reported to have anti-inflammatory and anti-oxidative properties. This study aims to evaluate the protective effects of naringenin against AgNPs-induced lung injury and determine the underlying mechanism. In in vivo experiments, AgNPs were intratracheally instilled into ICR mice (l mg/kg) to establish a lung injury model. These mice were then treated with naringenin by oral gavage (25, 50, 100 mg/kg) for three days. Naringenin treatment decreased the levels of white blood cells, neutrophils, and lymphocytes in the blood, ameliorated lung injury, suppressed the release of pro-inflammatory cytokines, normalized ferroptotic markers and prevented oxidative stress with elevating Nrf2 and HO-1 protein expressions in lung. In in vitro experiments, BEAS-2B cells were firstly treated with AgNPs (320 μg/mL) and then naringenin (25, 50, and 100 μM), respectively. Naringenin attenuated AgNPs-induced oxidative stress and inflammatory response. Moreover, naringenin attenuated AgNPs-induced apoptosis with modulated low BAX, CytC, cleaved Caspase9, cleaved Caspase3 but high Bcl2. Furthermore, naringenin effectively decreased ferroptotic markers and increased the protein expressions of Nrf2 and HO-1, as well as increased the nuclear translocation of Nrf2. Importantly, the anti-apoptotic and anti-ferroptotic effects of naringenin in BEAS-2B cells were found to be at least partially Nrf2-dependent. These results indicated that naringenin exerted anti-inflammation, anti-apoptosis, and anti-ferroptosis effects and protected against AgNPs-induced lung injury at least partly via activating Nrf2/HO-1 signaling pathway.

Integrating network pharmacology approach and experimental validation to reveal the alleviation of Shenkangning capsule on chronic nephritis

ETHNOPHARMACOLOGICAL RELEVANCE

Shenkangning (SKN), a Chinese patent medicine composed by eight Chinese medicinal herbs, is commonly applied to treat chronic glomerulonephritis (CGN) in clinic. However, its mechanism is still not clear now.

AIM OF THE STUDY

This study is designed to evaluate the SKN-provided alleviation on adriamycin (ADR)-induced nephropathy, to reveal its mechanism by integrating network pharmacology analysis and experimental evidences, and to further find the main drug that makes a major contribution to its efficacy.

MATERIALS AND METHODS

ADR was intravenously injected to mice to induce focal segmental glomerulosclerosis (FSGS). Renal histological evaluation was conducted. The level of urinary protein, and serum amounts of creatinine, urea nitrogen (BUN) and albumin were detected. The potential mechanisms were predicted by network pharmacology analysis and further validated by Real-time polymerase chain reaction (RT-PCR), Western-blot and enzyme-linked immunosorbent assay (ELISA).

RESULTS

SKN (1, 10 g/kg) improved ADR-induced nephropathy in mice. Network pharmacology results predicted that inflammation and oxidative stress were crucially involved in the SKN-provided amelioration on nephropathy. SKN reduced the activation of nuclear factor-κB (NF-κB) and the expression of some pro-inflammatory cytokines, and increased the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and the expression of its downstream genes in ADR-induced nephropathy in mice. Furthermore, SKN also restored the reduced expression of both podocin and synaptopodin, which are podocyte-associated proteins. Further results showed that the toxic drug Danfupian (DFP) had no contribution to the SKN-provided alleviation on ADR-induced nephropathy in mice. After integrating the results from evaluating anti-inflammation, anti-oxidant and anti-injury of podocytes in vitro and from comparing the activity of the whole SKN and SKN without Astragali Radix (Huangqi, HQ) in vivo, we found that HQ played a crucial contribution to the SKN-provided amelioration on ADR-induced nephropathy in mice.

CONCLUSION

SKN improved ADR-induced nephropathy through suppressing renal inflammation and oxidative stress injury via abrogating NF-κB activation and activating Nrf2 signaling pathway. HQ played a main contribution to the SKN-provided amelioration on ADR-induced nephropathy.

Role of Reactive Oxygen Species in Aging and Age-Related Diseases: A Review

Research on the role of reactive oxygen species (ROS) in the aging process has advanced significantly over the last two decades. In light of recent findings, ROS takes part in the aging process of cells along with contributing to various physiological signaling pathways. Antioxidants being cells' natural defense mechanism against ROS-mediated alteration, play an imperative role to maintain intracellular ROS homeostasis. Although the complete understanding of the ROS regulated aging process is yet to be fully comprehended, current insights into various sources of cellular ROS and their correlation with the aging process and age-related diseases are portrayed in this review. In addition, results on the effect of antioxidants on ROS homeostasis and the aging process as well as their advances in clinical trials are also discussed in detail. The future perspective in ROS-antioxidant dynamics on antiaging research is also marshaled to provide future directions for ROS-mediated antiaging research fields.

Is Dutasteride a Therapeutic Alternative for Amyotrophic Lateral Sclerosis?

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is characterized by the loss of upper and lower motor neurons (MNs) in the cerebral cortex, brainstem and spinal cord, with consequent weakness, atrophy and the progressive paralysis of all muscles. There is currently no medical cure, and riluzole and edaravone are the only two known approved drugs for treating this condition. However, they have limited efficacy, and hence there is a need to find new molecules. Dutasteride, a dual inhibitor of type 1 and type 2 5α-reductase (5AR) enzymes, the therapeutic purposes of which, to date, are the treatment of benign prostatic hyperplasia and androgenic alopecia, shows great anti-ALS properties by the molecular-topology methodology. Based on this evidence, this review aims to assess the effects of dutasteride on testosterone (T), progesterone (PROG) and 17β-estradiol (17BE) as a therapeutic alternative for the clinical improvement of ALS, based on the hormonal, metabolic and molecular pathways related to the pathogenesis of the disease. According to the evidence found, dutasteride shows great neuroprotective, antioxidant and anti-inflammatory effects. It also appears effective against glutamate toxicity, and it is capable of restoring altered dopamine activity (DA). These effects are achieved both directly and through steroid hormones. Therefore, dutasteride seems to be a promising molecule for the treatment of ALS, although clinical studies are required for confirmation.

A novel alginate from Sargassum seaweed promotes diabetic wound healing by regulating oxidative stress and angiogenesis

Diabetic skin ulcer is one of the most severe complications in diabetes, however, current therapeutic approaches are not effective enough. Agents modulating oxidative stress, inflammation, and angiogenesis are quite promising for alleviation of diabetic skin ulcers. In this study, a novel Sargassum kjellmanianum-derived polysaccharide (SARP) was prepared. SARP was an alginate with Mw of 45.4 kDa, consisting of 76.56% mannuronic acid, 18.89% guluronic acid, and 4.55% glucuronic acid. SARP could attenuate oxidative stress-induced cell damage via activating nuclear factor erythroid 2-related factor 2 (Nrf2). SARP also promoted the migration and tube formation of HUVECs, which was related to the increased vascular endothelial growth factor (VEGF) expression. In diabetic wound model, SARP (iv, 200 mg/kg) administration increased angiogenesis, alleviated oxidative stress, ameliorated diabetes-related aberrations, and thereby accelerated diabetic wound healing. These findings identified SARP had potential to be developed as a drug candidate for diabetic skin ulcers.

High-fat diet-induced intestinal dysbiosis is associated with the exacerbation of Sjogren’s syndrome

Environmental factors are believed to influence the evolution of primary Sjögren’s syndrome (pSS). The aims of this study were to investigate the association of pSS with a high-fat diet (HFD) and to relate HFD-induced gut dysbiosis to pSS exacerbation. Male Wild Type (WT) and IL-14α transgenic mice (IL-14α TG) were fed a standard diet (SD) and HFD for 11 months. We found an increase in the autoantibody level, more severe dry eye, severe dry mouth symptoms, and an earlier presence of systemic features in the IL-14α TG mice treated with HFD. These data suggest that HFD can promote the process of pSS in the IL-14α TG mice. In addition, an HFD leads to a decrease in the richness of gut microbiota of IL-14α TG mice treated with HFD. The abundance of Deferribacterota was significantly enriched in the IL-14α TG mice treated with HFD compared with other groups. Through the mental test between gut microbiota and clinical parameters, we found that HFD-induced dysbiosis gut microbiota were associated with pSS clinical parameters. In conclusion, HFD results in the aggravation of pSS progression, likely due to the increase of potentially pathogenic microorganisms.

Beneficial effects of procyanidin B2 on adriamycin-induced nephrotic syndrome mice: the multi-action mechanism for ameliorating glomerular permselectivity injury

Despite considerable advances in prevention, diagnosis, and therapy, nephrotic syndrome (NS) remains a significant cause of high morbidity and mortality globally. As a result, there is an urgent need to identify novel effective preventative and therapeutic agents for NS. NS is implicated in glomerular permselectivity injury, which can be attributed to oxidative distress, inflammation, lipid nephrotoxicity, podocyte apoptosis, autophagy dysfunction, and slit diaphragm (SLD) dysfunction. In addition to its well-documented antioxidant potency, procyanidin B2 (PB2) may exhibit pleiotropic effects by targeting various canonical signaling events, such as NF-κB, PPARs, PI3K/Akt, mTOR, and the caspase family. As a result, PB2 may be a promising therapeutic target against NS. To test this hypothesis, we established an Adriamycin (ADR)-induced NS mouse model to evaluate the pleiotropic renoprotective effects of PB2 on NS. Here, we demonstrated that PB2 improves podocyte injury via inhibition of NOX4/ROS and Hsp90/NF-κB to exhibit antioxidant and anti-inflammatory potency, respectively. We also show that PB2 indirectly activates the PI3K/Akt axis by regulating SLD protein levels, resulting in normalized podocyte apoptosis and autophagy function. Further, loss of albumin (ALB) induces lipid nephrotoxicity, which we found to be alleviated by PB2 via activation of PPARα/β-mediated lipid homeostasis and the cholesterol efflux axis. Interestingly, our results also suggested that PB2 reduces electrolyte abnormalities and edema. In addition, PB2 may contribute protective effects against trace element dys-homeostasis, which, through alleviating serum ALB loss, leads to a protective effect on glomerular permselectivity injury. Taken together, our results reveal that the identified mechanisms of PB2 on NS are multifactorial and involve inhibition of oxidative distress and inflammatory responses, as well as improvements in podocyte apoptosis and autophagy dysfunction, amelioration of lipid nephrotoxicity, and modulation of electrolyte abnormalities and edema. Thus, we provide a theoretical basis for the clinical application of PB2 against NS.

Activation of Atg7-dependent autophagy by a novel inhibitor of the Keap1-Nrf2 protein-protein interaction from Penthorum chinense Pursh. attenuates 6-hydroxydopamine-induced ferroptosis in zebrafish and dopaminergic neurons

The death of dopaminergic neurons is a dominant factor during the occurrence and development of Parkinson's disease (PD). Previous studies demonstrated that ferroptosis is implicated in the death of dopaminergic neurons. Besides, polyphenols have been proven to be effective in preventing the death of dopaminergic neurons. This work aims to explore the neuroprotective effect and mechanism of thonningianin A (Th A), a polyphenolic compound in natural plant foods, against 6-hydroxydopamine (6-OHDA)-induced ferroptosis in dopaminergic cells. The results of molecular docking and other binding assays collectively demonstrated that Th A can strongly target the Kelch domain of Keap1. Th A treatment significantly facilitated the nuclear factor erythroid 2-like 2 (Nrf2) nuclear translocation and subsequently increased the heme oxygenase-1 (HO-1) protein level through inhibiting the protein-protein interaction (PPI) of Keap1 and Nrf2. Compared with the nomifensine (Nomi) treatment, Th A had a more potent protective effect on 6-OHDA-induced ferroptosis during PD pathology in zebrafish, which was associated with assuaging the reduction of the total swimming distance, glutathione (GSH) depletion, iron accumulation, lipid peroxidation, and aggregation of α-synuclein (α-syn). Furthermore, Th A also exhibited a strong protective effect against 6-OHDA-induced ferroptosis in vitro in the human neuroblastoma cell line SH-SY5Y. Th A degraded Keap1 protein through activating Atg7-dependent autophagy. Additionally, Th A treatment facilitated the degradation of Keap1 protein by promoting the interaction between p62/SQSTM1 (sequestosome 1, hereafter referred to as p62) and Keap1. Taken together, our findings indicated that Th A protects dopaminergic cells against 6-OHDA-induced ferroptosis through activating the Nrf2-based cytoprotective system, thus enabling a potential application of Keap1-Nrf2 PPI inhibitors in the restraint of ferroptosis and treatment of PD.

Antioxidant Therapy in Cancer: Rationale and Progress

Cancer is characterized by increased oxidative stress, an imbalance between reactive oxygen species (ROS) and antioxidants. Enhanced ROS accumulation, as a result of metabolic disturbances and signaling aberrations, can promote carcinogenesis and malignant progression by inducing gene mutations and activating pro-oncogenic signaling, providing a possible rationale for targeting oxidative stress in cancer treatment. While numerous antioxidants have demonstrated therapeutic potential, their clinical efficacy in cancer remains unproven. Here, we review the rationale for, and recent advances in, pre-clinical and clinical research on antioxidant therapy in cancer, including targeting ROS with nonenzymatic antioxidants, such as NRF2 activators, vitamins, N-acetylcysteine and GSH esters, or targeting ROS with enzymatic antioxidants, such as NOX inhibitors and SOD mimics. In addition, we will offer insights into prospective therapeutic options for improving the effectiveness of antioxidant therapy, which may expand its applications in clinical cancer treatment.

Novel Keap1-Nrf2 Protein-Protein Interaction Inhibitor UBE-1099 Ameliorates Progressive Phenotype in Alport Syndrome Mouse Model

BACKGROUND

Bardoxolone methyl activates nuclear factor erythroid 2-related factor 2 (Nrf2) via covalent binding and irreversible inhibition of Kelch-like ECH-associated protein 1 (Keap1), the negative regulator of Nrf2. Ongoing clinical trials of bardoxolone methyl show promising effects for patients with CKD. However, the direct inhibition of Keap1-Nrf2 protein-protein interaction (PPI) as an approach to activate Nrf2 is less explored.

METHODS

We developed a noncovalent Nrf2 activator UBE-1099, which highly selectively inhibits Keap1-Nrf2 PPI, and evaluated its efficacy on the progressive phenotype in an Alport syndrome mouse model (Col4a5-G5X).

RESULTS

Similar to bardoxolone methyl, UBE-1099 transiently increased proteinuria and reduced plasma creatinine in Alport mice. Importantly, UBE-1099 improved the glomerulosclerosis, renal inflammation, and fibrosis, and prolonged the life span of Alport mice. UBE-1099 ameliorated the dysfunction of Nrf2 signaling in the renal tissue of Alport mice. Moreover, transcriptome analysis in the glomerulus showed that UBE-1099 induced the expression of genes associated with the cell cycle and cytoskeleton, which may explain its unique mechanism of improvement such as glomerular morphologic change.

CONCLUSIONS

UBE-1099 significantly ameliorates the progressive phenotype in Alport mice. Our results revealed the efficacy of Keap1-Nrf2 PPI inhibitor for glomerulosclerosis and present a potential therapeutic drug for CKD.

Protective effects of interleukin-22 on oxalate-induced crystalline renal injury via alleviating mitochondrial damage and inflammatory response

Oxalate-induced crystalline kidney injury is one of the most common types of crystalline nephropathy. Unfortunately, there is no effective treatment to reduce the deposition of calcium oxalate crystals and alleviate kidney damage. Thus, proactive therapeutic is urgently needed to alleviate the suffering it causes to patient. Here, we investigated whether IL-22 exerted nephroprotective effects to sodium oxalate-mediated kidney damage and its potential mechanism. Crystalline kidney injury models were developed in vitro and in vivo that was often observed in clinic. We provided evidence that IL-22 could effectively decrease the accumulation of ROS and mitochondrial damage in cell and animal models and reduce the death of TECs. Moreover, IL-22 decreased the expression of the NLRP3 inflammasome and mature IL-1β in renal tissue induced by sodium oxalate. Further studies confirmed that IL-22 could play an anti-inflammatory role by reducing the levels of cytokines such as IL-1β, IL-18, and TNF-α in serum. In conclusion, our study confirmed that IL-22 has protective effects on sodium oxalate-induced crystalline kidney injury by reducing the production of ROS, protecting mitochondrial membrane potential, and inhibiting the inflammatory response. Therefore, IL-22 may play a potential preventive role in sodium oxalate-induced acute renal injury. KEY POINTS: • IL-22 could reduce sodium oxalate-mediated cytotoxicity and ameliorate renal injury. • IL-22 could alleviate oxidative stress and mitochondrial dysfunction induced by sodium oxalate. • IL-22 could inhibit inflammatory response of renal injury caused by sodium oxalate.

Redox signaling at the crossroads of human health and disease

Redox biology is at the core of life sciences, accompanied by the close correlation of redox processes with biological activities. Redox homeostasis is a prerequisite for human health, in which the physiological levels of nonradical reactive oxygen species (ROS) function as the primary second messengers to modulate physiological redox signaling by orchestrating multiple redox sensors. However, excessive ROS accumulation, termed oxidative stress (OS), leads to biomolecule damage and subsequent occurrence of various diseases such as type 2 diabetes, atherosclerosis, and cancer. Herein, starting with the evolution of redox biology, we reveal the roles of ROS as multifaceted physiological modulators to mediate redox signaling and sustain redox homeostasis. In addition, we also emphasize the detailed OS mechanisms involved in the initiation and development of several important diseases. ROS as a double‐edged sword in disease progression suggest two different therapeutic strategies to treat redox‐relevant diseases, in which targeting ROS sources and redox‐related effectors to manipulate redox homeostasis will largely promote precision medicine. Therefore, a comprehensive understanding of the redox signaling networks under physiological and pathological conditions will facilitate the development of redox medicine and benefit patients with redox‐relevant diseases.

Ruscogenins Improve CD-Like Enteritis by Inhibiting Apoptosis of Intestinal Epithelial Cells and Activating Nrf2/NQO1 Pathway

Interaction of intestinal barrier dysfunction and intestinal inflammation promotes the progression of Crohn's disease (CD). A more recent study has suggested that ruscogenins (RUS) can exert anti-inflammatory effects through activation of the Nrf2/NQO1 pathway. The current study is aimed at determining the functionalization of RUS on CD-like colitis. Wild-type (WT) mice induced with trinitrobenzene sulfonic acid (TNBS) exhibit a significant inflammation in their colon and are hence widely used for CD models. In the current study, the mice were treated with the Nrf-2 antagonist (ML385) or ruscogenin (RUS) whereas normal WT mice were kept as the negative control. Comparative analysis was then performed on the inflammation and barrier function of the colons. In vitro analysis of mouse colonic organoid systems revealed the influence of RUS on LPS-induced apoptosis, cytokine, and chemokine expressions in the intestinal epithelium. It was found that RUS ameliorates murine colitis through activation of the Nrf2/NQO1 pathway which was presented as a decrease in inflammation score and downregulated levels of cytokine and chemokine synthesis, as well as increased intestinal permeability. Further, it was noted that RUS alleviated LPS-induced apoptosis in the intestinal epithelium cells through upregulation of the Nrf2/NQO1 signaling pathway in the mouse colonic organoids. In addition, ruscogenin (RUS) attenuated the levels of Bax and C-caspase-3 through activation of the Nrf2/HO1 signaling pathway both in vivo and in vitro. Therefore, it was evident that RUS can be applied as a potential alternative therapeutic agent in CD based on its protective effects on the barrier function and anti-inflammatory activity.

Effects of Exopolysaccharides from Lactiplantibacillus plantarum JLAU103 on Intestinal Immune Response, Oxidative Stress, and Microbial Communities in Cyclophosphamide-Induced Immunosuppressed Mice

This study investigated the effects of the exopolysaccharide from Lactiplantibacillus plantarum JLAU103 (EPS103) on the intestinal immune response, oxidative stress, intestinal mucosal barrier, and microbial community in cyclophosphamide-induced immune-suppressed mice. The results showed that EPS103 promoted the secretion of cytokines and the generation of secretory immunoglobulin A and mucin-2 in the small intestine of mice, which might be related to the activation of the MAPK pathway. Additionally, EPS103 protected against oxidative stress by activating antioxidation enzymes and Nrf2/Keap1 pathways. It also improved the intestinal physical barrier functions via regulating the ratio of villous height to crypt depth and upregulating the expression of tight-junction proteins. Meanwhile, EPS103 promoted the generation of short-chain fatty acids (SCFAs) and modulated the constituents of gut microbiota. These results suggested that EPS103 may modulate the intestinal immunoresponse relying on the regulation of SCFA production and gut microbiota in immunosuppressed mice, resulting in the activation of systemic immunity.

Cancer Chemopreventive Potential and Chemical Profiling of Euphorbia abyssinica Endowed with Docking Studies

Chemical profiling of both fruit and aerial part extracts of Euphorbia abyssinica via ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) showed them to be a rich source of diverse compounds. A total of 39 compounds in both extracts including flavonoids and phenolic compounds were identified as predominant metabolites. The antioxidant activity of both extracts was evaluated using three different in vitro assays (DPPH, ABTS, and FRAP assays). The E. abyssinica fruit extract demonstrated more potent activity compared to the aerial part extract (IC₅₀ of 85.1 ± 1.07 and 562.3 ± 1.01 μg/mL, respectively) in the DPPH assay. Furthermore, using ABTS and FRAP assays, the antioxidant capacities of the fruit extract were 1063.03 ± 37.8 and 1476.5 ± 95.6, respectively, calculated as μM Trolox equivalent/mg extract. One of the existing markers for cancer chemoprevention is the induction of phase II detoxifying enzyme NAD(P)H:quinone oxidoreductase 1 (NQO1), which plays a vital role in cytoprotection against oxidative damage. The extracts were assessed to test their chemopreventive potential via NQO1 enzyme induction. The methanolic extract of fruits demonstrated a concentration-dependent increase in the cancer chemopreventive marker enzyme NQO1 at the protein expression level in a murine hepatoma cell line (Hepa1c1c7). The interaction with Kelch-like ECH-associated protein 1 (KEAP1) is an essential transcription factor that controls the expression of the NQO1 enzyme. The demonstrated induction of NQO1 by the fruit extract is consistent with a molecular docking study of the effect of dereplicated compounds on the KEAP1 target. Among the dereplicated compounds, hesperidin, naringin, and rutin have been established as promising inducer compounds for the chemopreventive marker NQO1. Our results highlight the E. abyssinica fruit extract as a future chemopreventive lead.

The isoquinoline PRL-295 increases the thermostability of Keap1 and disrupts its interaction with Nrf2

Transcription factor Nrf2 and its negative regulator Keap1 orchestrate a cytoprotective response against oxidative, metabolic, and inflammatory stress. Keap1 is a drug target, with several small molecules in drug development. Here, we show that the isoquinoline PRL-295 increased Keap1 thermostability in lysates from cells expressing fluorescently tagged Keap1. The thermostability of endogenous Keap1 also increased in intact cells and murine liver following PRL-295 treatment. Fluorescence Lifetime Imaging-Förster Resonance Energy Transfer (FLIM-FRET) experiments in cells co-expressing sfGFP-Nrf2 and Keap1-mCherry further showed that PRL-295 prolonged the donor fluorescence lifetime, indicating disruption of the Keap1-Nrf2 protein complex. Orally administered PRL-295 to mice activated the Nrf2transcriptional target NAD(P)H:quinone oxidoreductase 1 (NQO1) in liver and decreased the levels of plasma alanine aminotransferase and aspartate aminotransferase upon acetaminophen-induced hepatic injury. Thus, PRL-295 engages the Keap1 protein target in cells and in vivo, disrupting its interaction with Nrf2, leading to activation of Nrf2-dependent transcription and hepatocellular protection.

Therapeutic benefits of flavonoids against neuroinflammation: a systematic review

Flavonoids are an important class of natural polyphenolic compounds reported to exert beneficial effects in cardiovascular and metabolic diseases, cancer, autoimmune and neurological disorders. Flavonoids possess potential antioxidant, anti-inflammatory, antiapoptotic and immuno-modulation properties. Intriguingly, the importance of flavonoids in different neurological disorders is gaining more attention due to the safety, better pharmacokinetic profile and blood-brain barrier penetration, cost-effectiveness and readiness for clinical uses/trials. Many in vitro and in vivo research studies have established the neuroprotective mechanism of flavonoids in the central nervous system (CNS) diseases. The present review summarizes the benefits of various classes of flavonoids (flavones, flavonols, flavanones, anthocyanidins, isoflavones, flavanols), chemical nature, classification, their occurrence and distribution, pharmacokinetics and bioavailability. The manuscript also presents available evidences relating to the role of flavonoids in regulating key signaling pathways such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway, mitogen-activated protein kinase (MAPK) pathway, Janus kinase and signal transducer and activator of transcription proteins (JAK/STAT) pathway, Toll-like receptors (TLR) pathway, nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and cAMP response element-binding protein (CREB) pathway involved in neuroinflammation associated with major neurological disorders. Literature search was conducted using electronic databases like Google Scholar, Scopus, PubMed central, Springer search and Web of science. Chemical structures used in the present analysis were drawn using Chemdraw Professional 15.0 software. This collective information provides comprehensive knowledge on disease pathways and therapeutic benefits of flavonoids in neurological disorders, druggability and future scope for research.

Dietary prenylated flavonoid xanthohumol alleviates oxidative damage and accelerates diabetic wound healing via Nrf2 activation

Diabetic skin ulcer is one of the most common complications in patients suffering diabetes mellitus. Xanthohumol (XN), a hop-derived prenylated dietary flavonoid, has multiple health beneficial bioactivities. In the present study, we reported XN alleviates oxidative damage and accelerates diabetic wound healing via Nrf2 activation. In vitro, XN attenuated hydrogen peroxide (H₂O₂)-induced cytotoxicity, ROS production, cell apoptosis, as well as high glucose-induced cell damage. Mechanistic studies further demonstrated that XN could stabilize nuclear factor erythroid 2-related factor 2 (Nrf2) and promote its nuclear translocation, which was associated with AMPKα activation and covalent modification of Keap1 by XN. In vivo, XN increased Nrf2 expression and accelerated diabetic wound healing. Our study revealed a novel function of XN in diabetic wound healing as well as the underlying molecular mechanisms, suggesting XN is a promising lead compound and a potential food and/or drug candidate for the treatment of diabetic skin ulcers.

Nrf2 expands the intracellular pool of the chaperone AHSP in a cellular model of β-thalassemia

In β-thalassemia, free α-globin chains are unstable and tend to aggregate or degrade, releasing toxic heme, porphyrins and iron, which produce reactive oxygen species (ROS). α-Hemoglobin-stabilizing protein (AHSP) is a potential modifier of β-thalassemia due to its ability to escort free α-globin and inhibit the cellular production of ROS. The influence of AHSP on the redox equilibrium raises the question of whether AHSP expression is regulated by components of ROS signaling pathways and/or canonical redox proteins. Here, we report that AHSP expression in K562 cells could be stimulated by NFE2-related factor 2 (Nrf2) and its agonist tert-butylhydroquinone (tBHQ). This tBHQ-induced increase in AHSP expression was also observed in Ter119+ mouse erythroblasts at each individual stage during terminal erythroid differentiation. We further report that the AHSP level was elevated in α-globin-overexpressing K562 cells and staged erythroblasts from β^IVS-2-654 thalassemic mice. tBHQ treatment partially alleviated, whereas Nrf2 or AHSP knockdown exacerbated, α-globin precipitation and ROS production in fetal liver-derived thalassemic erythroid cells. MafG and Nrf2 occupancy at the MARE-1 site downstream of the AHSP transcription start site was detected in K562 cells. Finally, we show that MafG facilitated the activation of the AHSP gene in K562 cells by Nrf2. Our results demonstrate Nrf2-mediated feedback regulation of AHSP in response to excess α-globin, as occurs in β-thalassemia.

An Integration of Network Pharmacology and Experimental Verification to Investigate the Mechanism of Guizhi to Treat Nephrotic Syndrome

Background: Guizhi has the pharmacological activity of anti-inflammatory. However, the effect mechanism of Guizhi against nephrotic syndrome (NS) remains unclear. A network pharmacological approach with experimental verification in vitro and in vivo was performed to investigate the potential mechanisms of Guizhi to treat NS.

Methods: Active compounds and potential targets of Guizhi, as well as the related targets of NS were obtained from the public databases. The intersecting targets of Guizhi and NS were obtained through Venny 2.1.0. The key targets and signaling pathways were determined by protein-protein interaction (PPI), genes ontology (GO) and kyoto encyclopedia of genes and genomes (KEGG) analysis. And the overall network was constructed with Cytoscape. Molecular docking verification was carried out by AutoDock Vina. Finally, in vitro and in vivo experiments were performed to verify the mechanism of Guizhi to treat NS.

Results: 63 intersecting targets were obtained, and the top five key targets mainly involed in NF- Kappa B and MAPK signaling pathway. In the overall network, cinnamaldehyde (CA) was the top one active compound with the highest degree value. The molecular docking showed that the top five key targets were of good binding activity with the active components of Guizhi. To in vitro experiment, CA, the main active component of Guizhi, inhibited the secretion of IL-1β, IL-6, TNF-α in LPS challenged RAW264.7 cells, and down regulated the protein expression of p-NF-κB p65 and p-p38 MAPK in LPS challenged RAW264.7 cells. In vitro experiment showed that, 24 urinary protein and renal function were increased in ADR group. To western blot, CA down regulated the protein expression of p-p38 MAPK in rats of adriamycin-induced nephropathy.

Conclusion: CA might be the main active component of Guizhi to treat NS, and the underlying mechanism might mainly be achieved by inhibiting MAPK signaling pathway.

Yiqi Huoxue Recipe inhibits cardiomyocyte apoptosis caused by heart failure through Keap1/Nrf2/HIF-1α signaling pathway

Yiqi Huoxue Recipe (YHR) is commonly used in China to treat diseases such as heart failure (HF). It has been reported that YHR can treat HF and has a certain protective effect on myocardial cell damage. The purpose of this study is to determine the cardioprotective effects of YHR on HF-induced apoptosis and to clarify its mechanism of action. Oxygen glucose deprivation/recovery (OGD/R) induces H9C2 cell apoptosis model. Ligation of the left anterior descending artery (LAD) coronary artery can induce an animal model of HF. We found that YHR protected H9C2 cells from OGD/R-induced apoptosis, reduced the level of reactive oxygen species (ROS) in H9C2 cells, and increased the mitochondrial membrane potential in H9C2 cells. The results of in vivo animal experiments showed that in the HF model, YHR could reduce infarct area of heart tissue and cardiomyocyte apoptosis rate. YHR regulated the expression of key apoptotic molecules, including increasing the ratio of Bcl-2 and Bax, and reducing the expression of Kelch-like ECH-associated protein 1 (Keap1) and caspase-3. Interestingly, YHR also regulates the expression of NF-E2-related factor 2 (Nrf2) in the nucleus. In summary, YHR may provide cardioprotective effects in heart failure through inhibiting the Keap1/Nrf2/HIF-1α apoptosis pathway.

Diterpenoid alkaloids from Delphinium forrestii var. viride and their anti-inflammation activity

Six undescribed diterpenoid alkaloids including five C₁₉-diterpenoid alkaloids forrestlines A-E, and one C₂₀-diterpenoid alkaloid forrestline F, together with nine known alkaloids have been isolated from the whole herbs of Delphinium forrestii var. vride. Their structures were elucidated by spectroscopic data, and their inhibitory activities on NO production stimulated by LPS in RAW264.7 macrophage cells were determined. Then, forrestline F, with the strongest inhibitory activity (IC₅₀ of 9.57 ± 1.43 μM), was selected to study its possible anti-inflammatory mechanism. ELISA results showed that forrestline F suppressed inflammatory cytokines, including interleukin-1β (IL-1β), tumor necrosisfactor-α (TNF-α), and interleukin-6 (IL-6). Moreover, forrestline F could down-regulate LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) by western blotting assay. It also inhibited expression of phosphorylation of MAPKs (including p-p38, p-ERK and p-JNK), and NF-κB p65, and decreased ROS accumulation by upregulating the expression of HO-1 expression via nuclear translocation of Nrf2. In conclusion, forrestline F showed anti-inflammatory effect by inhibiting NF-κB/MAPK and Nrf2/HO-1 signaling pathway. Therefore, forrestline F could be a promising molecule for the development of anti-inflammatory agents in the future.

Renal ischemia/reperfusion injury in rats is probably due to the activation of the 5-HT degradation system in proximal renal tubular epithelial cells

AIMS

To explore the relationship between renal ischemia/reperfusion injury (RIRI) and the activation of the renal 5-HT degradation system, including 5-HT_2A receptor (5-HT_2AR), 5-HT synthases and monoamine oxidase-A (MAO-A).

MAIN METHODS

Rat RIRI was induced by removing the right kidney, causing ischemia of the left kidney for 45 min and reperfusion for different times. RIRI model (ischemia for 45 min and reperfusion for 24 h) was pretreated with 5-HT_2AR antagonist sarpogrelate hydrochloride (SH) and the 5-HT synthase inhibitor carbidopa. In HK-2 cells, cellular damage was induced by hypoxia (24 h)/reoxygenation (12 h) (H/R) and treated with SH, carbidopa or the MAO-A inhibitor clorgyline. Hematoxylin-eosin, immunohistochemistry, TUNEL and fluorescent probe staining, RT-qPCR, western blotting, ELISA, etc. were used in the tests.

KEY FINDINGS

The development of RIRI and the emergence of the RIRI peak were consistent with renal 5-HT degradation system activation. The highest expression regions of the 5-HT degradation system overlapped with those of the most severe lesions in the kidney, which were in proximal renal tubules. Rat RIRI and HK-2 cell damage, including oxidative stress, inflammation and apoptosis, could be almost abolished by synergistic inhibition of SH and carbidopa. Clorgyline also abolished the cellular damage induced by H/R. H/R-induced production of mitochondrial ROS in HK-2 cells was due to MAO-A-catalyzed 5-HT degradation, and 5-HT_2AR was involved by mediating the expression of 5-HT synthases and MAO-A.

SIGNIFICANCE

These findings revealed a close association between RIRI and activation of the renal 5-HT degradation system.

NRF2 Exerts Anti-Inflammatory Effects in LPS-Induced gEECs by Inhibiting the Activation of the NF-κB

Nuclear factor E2-related factor 2 (NRF2) plays an anti-inflammatory role in several pathological processes, but its function in lipopolysaccharide- (LPS-) induced goat endometrial epithelial cells (gEECs) is still unknown. We designed a study to investigate the function of NRF2 in LPS-induced gEECs. LPS was found to increase the NRF2 expression and the nuclear abundance of NRF2 in gEECs in a dose-dependent manner. NRF2 knockout (KO) not only increased the expression of LPS-induced proinflammatory cytokines (TNF-α, IL-1β, IL-6 and IL-8) but also increased the expression of TLR4, p-IκBα/IκBα, and p-p65/p65 proteins. Immunoprecipitation experiments showed that NRF2 directly binds to p65 in the nucleus and inhibits the binding of p65 to downstream target genes (TNF-α, IL-1β, IL-6, and IL-8). Even though a NF-κB/p65 inhibitor (PDTC) reduced the LPS-induced NRF2 expression and nuclear abundance of NRF2, overexpressing TNF-α reversed the inhibitory effects of PDTC on the NRF2 expression and on its abundance in the nucleus. Similarly, knockdown of the proinflammatory cytokines (TNF-α, IL-1β, IL-6, or IL-8) significantly decreased the LPS-induced NRF2 expression and NRF2 in the nucleus. In conclusion, our data suggest that proinflammatory cytokines induced by LPS through the TLR4/NF-κB pathway promote the NRF2 expression and its translocation into the nucleus. Our work also suggests that NRF2 inhibits the expression of proinflammatory cytokines by directly binding to p65.

LINCS Dataset-Based Repositioning of Dutasteride as an Anti-Neuroinflammation Agent

Neuroinflammation is often accompanied by central nervous system (CNS) injury seen in various CNS diseases, with no specific treatment. Drug repurposing is a strategy of finding new uses for approved or investigational drugs, and can be enabled by the Library of Integrated Network-based Cellular Signatures (LINCS), a large drug perturbation database. In this study, the signatures of Lipopolysaccharide (LPS) were compared with the signatures of compounds contained in the LINCS dataset. To the top 100 compounds obtained, the Quantitative Structure-Activity Relationship (QSAR)-based tool admetSAR was used to identify the top 10 candidate compounds with relatively high blood–brain barrier (BBB) penetration. Furthermore, the seventh-ranked compound, dutasteride, a 5-α-reductase inhibitor, was selected for in vitro and in vivo validation of its anti-neuroinflammation activity. The results showed that dutasteride significantly reduced the levels of IL-6 and TNF-α in the supernatants of LPS-stimulated BV2 cells, and decreased the levels of IL-6 in the hippocampus and plasma, and the number of activated microglia in the brain of LPS administration mice. Furthermore, dutasteride also attenuated the cognitive impairment caused by LPS stimulation in mice. Taken together, this study demonstrates that the LINCS dataset-based drug repurposing strategy is an effective approach, and the predicted candidate, dutasteride, has the potential to ameliorate LPS-induced neuroinflammation and cognitive impairment.

A bioactive ligand-conjugated iridium(III) metal-based complex as a Keap1-Nrf2 protein-protein interaction inhibitor against acetaminophen-induced acute liver injury

Hepatotoxicity caused by an overdose of acetaminophen (APAP) is the leading reason for acute drug-related liver failure. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a protein that helps to regulate redox homeostasis and coordinate stress responses via binding to the Kelch-like ECH-associated protein 1 (Keap1). Targeting the Keap1-Nrf2 interaction has recently emerged as a potential strategy to alleviate liver injury caused by APAP. Here, we designed and synthesized a number of iridium (III) and rhodium (III) complexes bearing ligands with reported activity against oxidative stress, which is associated with Nrf2 transcriptional activation. The iridium (III) complex 1 bearing a bioactive ligand 2,9-dimethyl-1,10-phenanthroline and 4-chloro-2-phenylquinoline, a derivative of the bioactive ligand 2-phenylquinoline, was identified as a direct small-molecule inhibitor of the Keap1–Nrf2 protein-protein interaction. 1 could stabilize Keap1 protein, upregulate HO-1 and NQO1, and promote Nrf2 nuclear translocation in normal liver cells. Moreover, 1 reversed APAP-induced liver damage by disrupting Keap1–Nrf2 interaction and without inducing organ damage and immunotoxicity in mice. Our study demonstrates the identification of a selective and efficacious antagonist of Keap1–Nrf2 interaction possessed good cellular permeability in cellulo and ideal pharmacokinetic parameters in vivo, and, more importantly, validates the feasibility of conjugating metal complexes with bioactive ligands to generate metal-based drug leads as non-toxic Keap1–Nrf2 interaction inhibitors for treating APAP-induced acute liver injury.

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1 reversed APAP-induced liver damage by disrupting Keap1–Nrf2 interaction without inducing organ damage or immunotoxicity.

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Complex 1 possessed good cellular permeability in cellulo and ideal pharmacokinetic parameters in vivo.

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Conjugating metal complexes with bioactive ligands opens a novel avenue for the treatment of APAP-induced liver damage.