Esculin induces endoplasmic reticulum stress and drives apoptosis and ferroptosis in colorectal cancer via PERK regulating eIF2α/CHOP and Nrf2/HO-1 cascades

ETHNOPHARMACOLOGICAL RELEVANCE

Cortex fraxini (also known as Qinpi), the bark of Fraxinus rhynchophylla Hance and Fraxinus stylosa Lingelsh, constitutes a crucial component in several traditional Chinese formulas (e.g., Baitouweng Tang, Jinxiao Formula, etc.) and has demonstrated efficacy in alleviating intestinal carbuncle and managing diarrhea. Cortex fraxini has demonstrated commendable anticancer activity in the realm of Chinese ethnopharmacology; nevertheless, the underlying mechanisms against colorectal cancer (CRC) remain elusive.

AIM OF THE STUDY

Esculin, an essential bioactive compound derived from cortex fraxini, has recently garnered attention for its ability to impede viability and induce apoptosis in cancer cells. This investigation aims to assess the therapeutic potential of esculin in treating CRC and elucidate the underlying mechanisms.

MATERIALS AND METHODS

The impact of esculin on CRC cell viability was assessed using CCK-8 assay, Annexin V/PI staining, and Western blotting. Various cell death inhibitors, along with DCFH-DA, ELISA, biochemical analysis, and Western blotting, were employed to delineate the modes through which esculin induces HCT116 cells death. Inhibitors and siRNA knockdown were utilized to analyze the signaling pathways influenced by esculin. Additionally, an azomethane/dextran sulfate sodium (AOM/DSS)-induced in vivo CRC mouse model was employed to validate esculin's potential in inhibiting tumorigenesis and to elucidate its underlying mechanisms.

RESULTS

Esculin significantly suppressed the viability of various CRC cell lines, particularly HCT116 cells. Investigation with diverse cell death inhibitors revealed that esculin-induced cell death was associated with both apoptosis and ferroptosis. Furthermore, esculin treatment triggered cellular lipid peroxidation, as evidenced by elevated levels of malondialdehyde (MDA) and decreased levels of glutathione (GSH), indicative of its propensity to induce ferroptosis in HCT116 cells. Enhanced protein levels of protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) and p-eIF2α suggested that esculin induced cellular endoplasmic reticulum (ER) stress, subsequently activating the Nrf2/ARE signaling pathway and initiating the transcriptional expression of heme oxygenase (HO)-1. Esculin-induced excessive expression of HO-1 could potentially lead to iron overload in HCT116 cells. Knockdown of Ho-1 significantly attenuated esculin-induced ferroptosis, underscoring HO-1 as a critical mediator of esculin-induced ferroptosis in HCT116 cells. Furthermore, utilizing an AOM/DSS-induced colorectal cancer mouse model, we validated that esculin potentially inhibits the onset and progression of colon cancer by inducing apoptosis and ferroptosis in vivo.

CONCLUSIONS

These findings provide comprehensive insights into the dual induction of apoptosis and ferroptosis in HCT116 cells by esculin. The activation of the PERK signaling pathway, along with modulation of downstream eIF2α/CHOP and Nrf2/HO-1 cascades, underscores the mechanistic basis supporting the clinical application of esculin on CRC treatment.

Ginseng-derived nanoparticles alleviate alcohol-induced liver injury by activating the Nrf2/HO-1 signalling pathway and inhibiting the NF-κB signalling pathway in vitro and in vivo

BACKGROUND

Previous studies have confirmed the antioxidant and anti-inflammatory effects of active ginseng components that protect against liver injury. However, ginseng-derived nanoparticles (GDNPs), low-immunogenicity nanovesicles derived from ginseng, have not been reported to be hepatoprotective.

PURPOSE

In this study, we investigated whether GDNPs could attenuate alcohol-induced liver injury in LO2 cells and mice by modulating oxidative stress and inflammatory pathways, thereby advancing the theoretical basis for the development of novel pharmacological treatments.

STUDY DESIGN

Alcohol was used to construct in vitro and in vivo models of alcoholic liver injury. To explore the mechanisms by which GDNPs exert their protective effects against alcoholic liver injury, we examined the expression of oxidative stress-related genes and analysed inflammatory responses in vitro and in vivo. The experimental findings were verified using network pharmacology.

METHODS

The composition of the GDNPs was analysed using liquid chromatography-mass spectrometry. GDNPs were extracted and purified using differential ultracentrifugation and sucrose density gradient centrifugation. In vitro models of alcoholic liver injury were established using LO2 cells, whereas C57BL/6 J mice were used as in vivo models. Oxidative stress, inflammation, and liver injury indicators were measured using appropriate kits. Levels of proteins associated with oxidative stress and inflammation were measured via western blot, while nuclear factor erythroid2-related factor 2 (Nrf2) and NF-κB protein expression was tested using immunofluorescence, immunohistochemistry, and flow cytometry. The levels of relevant transcription factors were determined using qPCR. Experimental haematoxylin and eosin staining was used to characterise the liver histological appearance and damage in mice. Network pharmacological analysis of GDNP mRNA sequencing of GDNPs was used to predict drug targets and disease associations using TCMSP.

RESULTS

GDNPs primarily included 77 compounds, including organic acids and their derivatives, amino acids and their derivatives, sugars, terpenoids, and flavonoids. GDNPs have features that allow them to be taken up by LO2 cells and promote their proliferation. In vitro data indicated that GDNPs reduced the levels of alcohol-induced reactive oxygen species by activating the Nrf2/HO-1 signalling pathway, whilst inhibiting the NF-κB pathway and thereby reducing NO, tumour necrosis factor-α, and interleukin-1β levels to alleviate inflammation. An in vivo model showed that GDNPs improved the liver parameters and pathology in mice with alcoholic liver injury. GDNPs activate the Nrf2/HO-1/Keap1 signalling pathway in a p62-dependent manner to exert antioxidant effects. Furthermore, the TLR4/NF-κB signalling pathway was involved in the in vivo anti-inflammatory effect. Network pharmacology also confirmed that the effects of GDNPs on liver disease were associated with oxidative stress and inflammation-related targets and pathways.

CONCLUSION

This study showed for the first time that GDNPs can alleviate alcohol-induced liver damage by activating the Nrf2/HO1 signalling pathway and blocking the NF-κB signalling pathway, thus lowering oxidative stress and inflammatory responses. Hereby, we present the Nrf2/HO1 and NF-κB signalling pathways as potential targets and GDNPs as a novel therapeutic approach for the management of alcohol-induced liver damage.

Activation of Heme Oxygenase-1 by Mangiferin in Human Retinal Pigment Epithelial Cells Contributes to Blocking Oxidative Damage

Mangiferin is a kind of natural xanthone glycosides and is known to have various pharmacological activities. However, since the beneficial efficacy of this compound has not been reported in retinal pigment epithelial (RPE) cells, this study aimed to evaluate whether mangiferin could protect human RPE ARPE-19 cells from oxidative injury mimicked by hydrogen peroxide (H2O2). The results showed that mangiferin attenuated H2O2-induced cell viability reduction and DNA damage, while inhibiting reactive oxygen species (ROS) production and preserving diminished glutathione (GSH). Mangiferin also antagonized H2O2-induced inhibition of the expression and activity of antioxidant enzymes such as manganese superoxide dismutase and GSH peroxidase, which was associated with inhibition of mitochondrial ROS production. In addition, mangiferin protected ARPE-19 cells from H2O2-induced apoptosis by increasing the Bcl-2/Bax ratio, decreasing caspase-3 activation, and blocking poly(ADP-ribose) polymerase cleavage. Moreover, mangiferin suppressed the release of cytochrome c into the cytosol, which was achieved by interfering with mitochondrial membrane disruption. Furthermore, mangiferin increased the expression and activity of heme oxygenase-1 (HO-1) and nuclear factor-erythroid-2 related factor 2 (Nrf2). However, the inhibition of ROS production, cytoprotective and anti-apoptotic effects of mangiferin were significantly attenuated by the HO-1 inhibitor, indicating that mangiferin promoted Nrf2-mediated HO-1 activity to prevent ARPE-19 cells from oxidative injury. The results of this study suggest that mangiferin, as an Nrf2 activator, has potent ROS scavenging activity and may have the potential to protect oxidative stress-mediated ocular diseases.

Bilirubin ameliorates osteoarthritis via activating Nrf2/HO-1 pathway and suppressing NF-κB signalling

Osteoarthritis (OA) is a chronic degenerative joint disease that affects worldwide. Oxidative stress plays a critical role in the chronic inflammation and OA progression. Scavenging overproduced reactive oxygen species (ROS) could be rational strategy for OA treatment. Bilirubin (BR) is a potent endogenous antioxidant that can scavenge various ROS and also exhibit anti-inflammatory effects. However, whether BR could exert protection on chondrocytes for OA treatment has not yet been elucidated. Here, chondrocytes were exposed to hydrogen peroxide with or without BR treatment. The cell viability was assessed, and the intracellular ROS, inflammation cytokines were monitored to indicate the state of chondrocytes. In addition, BR was also tested on LPS-treated Raw264.7 cells to test the anti-inflammation property. An in vitro bimimic OA microenvironment was constructed by LPS-treated Raw264.7 and chondrocytes, and BR also exert certain protection for chondrocytes by activating Nrf2/HO-1 pathway and suppressing NF-κB signalling. An ACLT-induced OA model was constructed to test the in vivo therapeutic efficacy of BR. Compared to the clinical used HA, BR significantly reduced cartilage degeneration and delayed OA progression. Overall, our data shows that BR has a protective effect on chondrocytes and can delay OA progression caused by oxidative stress.

alleviates LPS-induced acute lung injury by inhibiting p47phox/NOX2 and promoting the Nrf2/HO-1 signaling pathway

BACKGROUND & AIMS

The effect fraction of Bletilla striata (Thunb.) Reichb.f. (EFBS), a phenolic-rich extract, has significant protective effects on lipopolysaccharide (LPS)-induced acute lung injury (ALI), but its composition and molecular mechanisms are unclear. This study elucidated its chemical composition and possible protective mechanisms against LPS-induced ALI from an antioxidant perspective.

METHODS

EFBS was prepared by ethanol extraction, enriched by polyamide column chromatography, and characterized using ultra-performance liquid chromatography/time-of-flight mass spectrometry. The LPS-induced ALI model and the RAW264.7 model were used to evaluate the regulatory effects of EFBS on oxidative stress, and transcriptome analysis was performed to explore its possible molecular mechanism. Then, the pathway by which EFBS regulates oxidative stress was validated through inhibitor intervention, flow cytometry, quantitative PCR, western blotting, and immunofluorescence techniques.

RESULTS

A total of 22 compounds in EFBS were identified. The transcriptome analyses of RAW264.7 cells indicated that EFBS might reduce reactive oxygen species (ROS) production by inhibiting the p47phox/NADPH oxidase 2 (NOX2) pathway and upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. Both in vitro and in vivo data confirmed that EFBS significantly inhibited the expression and phosphorylation of p47phox protein, thereby weakening the p47phox/NOX2 pathway and reducing ROS production. EFBS significantly increased the expression of Nrf2 in primary peritoneal macrophages and lung tissue and promoted its nuclear translocation, dose-dependent increase in HO-1 levels, and enhancement of antioxidant activity. In vitro, both Nrf2 and HO-1 inhibitors significantly reduced the scavenging effects of EFBS on ROS, further confirming that EFBS exerts antioxidant effects at least partially by upregulating the Nrf2/HO-1 pathway.

CONCLUSIONS

EFBS contains abundant phenanthrenes and dibenzyl polyphenols, which can reduce ROS production by inhibiting the p47phox/NOX2 pathway and enhance ROS clearance activity by upregulating the Nrf2/HO-1 pathway, thereby exerting regulatory effects on oxidative stress and improving LPS-induced ALI.

Punicalagin from pomegranate ameliorates TNF-α/IFN-γ-induced inflammatory responses in HaCaT cells via regulation of SIRT1/STAT3 axis and Nrf2/HO-1 signaling pathway

Punicalagin (PUN) was isolated from the peel of pomegranate (Punica granatum L.), is a polyphenol with anti-inflammatory, hepatoprotective, and antioxidant activities. However, it remains unclear whether PUN alleviates the inflammation and anti-inflammatory mechanisms in pro-inflammatory cytokines-induced human keratinocyte HaCaT cells. Here, we investigated that tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) mixture-stimulated HaCaT cells were treated with various concentrations of PUN, followed by analyzed the expression of inflammation-related mediators and evaluate anti-inflammatory-related pathways. Our results demonstrated that PUN ≤ 100 μM did not reduce HaCaT cell viability, and PUN ≥ 3 μM was sufficient to decrease interleukin-6 (IL-6), IL-8, monocyte chemoattractant protein-1 (MCP-1), chemokine ligand 5 (CCL5), CCL17 and CCL20 concentrations. We found that PUN ≥ 10 μM and ≥ 3 μM significantly increased sirtuin 1 (SIRT1) expression and inhibited signal transducer and activator of transcription 3 (STAT3) phosphorylation, respectively. PUN downregulated inflammation-related proteins cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS), enhanced nuclear factor erythroid-2-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1) expression. Moreover, PUN decreased intercellular adhesion molecule-1 (ICAM-1) expression and inhibited monocyte adhesion to inflamed HaCaT cells. PUN also suppressed inflammatory-related pathways, including mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways in TNF-α/IFN-γ- stimulated HaCat cells. Collectively, there is significant evidence that PUN has effective protective defenses against TNF-α/IFN-γ-induced skin inflammation by enhancing SIRT1 to mediate STAT3 and Nrf2/HO-1 signaling pathway.

Enniatin B1 induces damage to Leydig cells via inhibition of the Nrf2/HO-1 and JAK/STAT3 signaling pathways

Enniatin B1 (ENN B1) is a mycotoxin that can be found in various foods. However, whether ENN B1 is hazardous to the reproductive system is still elusive. Leydig cells are testosterone-generating cells that reside in the interstitial compartment between seminiferous tubules. Dysfunction of Leydig cells could result in male infertility. This study aimed to examine the toxicological effects of ENN B1 against TM3 Leydig cells. ENN B1 significantly inhibited cell viability in a dose-dependent manner. ENN B1 treatment also decreased the expression of functional genes in Leydig cells. Moreover, ENN B1 induced Leydig cells apoptosis and oxidative stress. Mechanistically, ENN B1 leads to the upregulation of Bax and downregulation of Bcl-2 in Leydig cells. In addition, ENN B1 inhibited the Nrf2/HO-1 pathway, which is critical for the induction of oxidative stress. Additionally, ENN B1 treatment repressed the JAK/STAT3 signaling pathway in Leydig cells. Rescue experiments showed that activation of STAT3 resulted in alleviation of ENN B1-induced damage in Leydig cells. Collectively, our study demonstrated that ENN B1 induced Leydig cell dysfunction via multiple mechanisms.

CLPs-miR-103a-2-5p inhibits proliferation and promotes cell apoptosis in AML cells by targeting LILRB3 and Nrf2/HO-1 axis, regulating CD8 + T cell response

BACKGROUND

LILRB3, a member of the leukocyte immunoglobulin-like receptor B (LILRB) family, has immunosuppressive functions and directly regulates cancer development, which indicates that LILRB3 is an attractive target for cancer diagnosis and therapy. Novel therapeutic treatments for acute myeloid leukemia (AML) are urgent and important, and RNA therapeutics including microRNAs (miRNAs) could be an effective option. Here, we investigate the role of dysregulated miRNA targeting LILRB3 in the AML microenvironment.

METHODS

Potential miRNAs binding to the 3'-untranslated region (3'-UTR) of the LILRB3 mRNA were predicted by bioinformatics websites. Then, we screened miRNAs targeting LILRB3 by quantitative real-time PCR, and the dual luciferase reporter assay. The expression of LILRB3 and microRNA (miR)-103a-2-5p in AML were determined and then their interactions were also analyzed. In vitro, the effects of miR-103a-2-5p were determined by CCK8, colony formation assay, and transwell assay, while cell apoptosis and cell cycle were analyzed by flow cytometry. Cationic liposomes (CLPs) were used for the delivery of miR-103a-2-5p in the AML mouse model, which was to validate the potential roles of miR-103a-2-5p in vivo.

RESULTS

LILRB3 was upregulated in AML cells while miR-103a-2-5p was dramatically downregulated. Thus, a negative correlation was found between them. MiR-103a-2-5p directly targeted LILRB3 in AML cells. Overexpressed miR-103a-2-5p significantly suppressed the mRNA and protein levels of LILRB3, thereby inhibiting AML cell growth and reducing CD8 + T cell apoptosis. In addition, overexpressed miR-103a-2-5p reduced both the relative expression of Nrf2/HO-1 pathway-related proteins and the ratio of GSH/ROS, leading to the excessive intracellular ROS that may promote AML cell apoptosis. In the mouse model, the delivery of miR-103a-2-5p through CLPs could inhibit tumor growth.

CONCLUSIONS

MiR-103a-2-5p serves as a tumor suppressor that could inhibit AML cell proliferation and promote their apoptosis by downregulating LILRB3 expression, suppressing the Nrf2/HO-1 axis, and reducing the ratio of GSH/ROS. Besides, our findings indicate that miR-103a-2-5p may enhance the CD8 + T cell response by inhibiting LILRB3 expression. Therefore, the delivery of miR-103a-2-5p through CLPs could be useful for the treatment of AML.

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.

Gastrodin alleviates premature senescence of vascular endothelial cells by enhancing the Nrf2/HO-1 signalling pathway

Endothelial dysfunction is an independent risk factor for stroke. The dysfunction of endothelial cells (EC) is closely concerned with EC senescence. Gastrodin (GAS) is an organic compound extracted from the dried root mass of the Orchidaceae plant Gastrodiae gastrodiae. It is used clinically to treat diseases such as vertebrobasilar insufficiency, vestibular neuronitis and vertigo. In the present study, we used hydrogen peroxide (H2 O2 )-induced human umbilical vein endothelial cells (HUVECs) to establish an in vitro EC senescence model and to investigate the role and mechanism of GAS in EC senescence. It's found that H2 O2 -treated HUVECs increased the proportion of senescence-associated β-galactosidase (SA β-gal) positive cells and the relative protein expression levels of senescence-associated cyclin p16 and p21. In addition, GAS reduced the proportion of SA β-gal positive cells and the relative protein expression levels of p16 and p21, and increased the proliferation and migration ability of HUVECs. Meanwhile, GAS increased the expression of the anti-oxidative stress protein HO-1 and its nuclear expression level of Nrf2. The anti-senescence effect of GAS was blocked when HO-1 expression was inhibited by SnPPIX. Furthermore, absence of HO-1 abolished the effect of GAS on HUVEC proliferation and migration. In conclusion, GAS ameliorated H2 O2 -induced cellular senescence and enhanced cell proliferation and migration by enhancing Nrf2/HO-1 signalling in HUVECs. These findings of our study expanded the understanding of GAS pharmacology and suggested that GAS may offer a potential therapeutic agent for stroke.

Resveratrol attenuates intestinal epithelial barrier dysfunction via Nrf2/HO-1 pathway in dextran sulfate sodium-induced Caco-2 cells

INTRODUCTION

The intestinal tract serves as an innate barrier, safeguarding the internal milieu from microorganisms and toxins. Various intestinal inflammatory diseases have a strong association with intestinal barrier dysfunction. The primary functional cells within the intestinal tract, intestinal epithelial cells (IECs) and their tight junctions (TJs), are crucial in preserving the integrity of this mechanical barrier. Resveratrol (Res), a plant-derived phenolic compound, exhibits a range of health-promoting benefits attributed to its anti-inflammatory properties. This study aims to examine Res's efficacy in bolstering IECs barrier function.

METHODS

Dextran sulfate sodium (DSS) was employed to induce barrier dysfunction in IECs. Inflammatory cytokines in supernatants (interleukin [IL]-6, IL-1β, tumor necrotic factor [TNF]-α, and IL-10) were quantified via enzyme-linked immunosorbent assay (ELISA). Then we assessed monolayer integrity using transepithelial electrical resistance (TEER). TJ protein expression (zonula occludens [ZO]-1 and Occludin) in IECs was evaluated through immunofluorescence and Western blot analysis. Network pharmacology helped identify the biological processes, signaling pathways, and key targets involved in Res's mitigation of DSS-induced IECs barrier dysfunction. The efficacy of the primary target was further corroborated using Western blot.

RESULTS

Res was shown to increase cell viability and IL-10 expression while reducing TNF-α, IL-6, and IL-1β levels, thus mitigating the inflammatory response. It enhanced TEER values and upregulated TJ protein expression (ZO-1 and Occludin). Network pharmacology revealed that Res potentially targets the NFE2L2 (nuclear factor erythroid-2-related factor 2, Nrf2), a vital antioxidant factor. Significantly, Res augmented Nrf2 and heme oxygenase 1 (HO-1) protein levels, counteracting oxidative stress in the IECs barrier dysfunction model.

CONCLUSION

Overall, our findings suggested that Res ameliorated DSS-induced IECs barrier dysfunction by activating Nrf2/HO-1 pathway, showcasing significant therapeutic potential in the early stages of colitis.

Nrf2/HO-1 Alleviates Disulfiram/Copper-Induced Ferroptosis in Oral Squamous Cell Carcinoma

Accumulating evidence indicates that the disulfiram/copper complex (DSF/Cu) has been shown to have potent antitumor activity against various cancers. This research evaluated the effects and probable mechanisms of DSF/Cu on oral squamous cell carcinoma (OSCC). In this study, we report the toxicity of the DSF/Cu to OSCC both in vitro and in vivo. Our study showed that DSF/Cu reduced the proliferation and clonogenicity of OSCC cells. DSF/Cu also induced ferroptosis. Importantly, we confirmed that DSF/Cu could increase the free iron pool, enhance lipid peroxidation, and eventually result in ferroptosis cell death. Inhibition of NRF2 or HO-1 enhances the sensitivity of OSCC cells to DSF/Cu-induced ferroptosis. DSF/Cu inhibited the xenograft growth of OSCC cells by suppressing the expression of Nrf2/HO-1. In conclusion, these results provide experimental evidence that Nrf2/HO-1 alleviates DSF/Cu-induced ferroptosis in OSCC. We propose that this therapy could be a novel strategy for treating OSCC.

Dual role of Nrf2/HO-1 pathway in Z-ligustilide-induced ferroptosis against AML cells

BACKGROUND

The scarcity of drugs targeting AML cells poses a significant challenge in AML management. Z-Ligustilide (Z-LIG), a phthalide compound, shows promising pharmacological potential as a candidate for AML therapy. However, its precise selective mechanism remains unclear.

PURPOSE

In order to assess the selective inducement effects of Z-LIG on ferroptosis in AML cells and explore the possible involvement of the Nrf2/HO-1 pathway in the regulation of ferroptosis.

METHODS

Through in vitro cell proliferation and in vivo tumor growth tests, the evaluation of Z-LIG's anticancer activity was conducted. Ferroptosis was determined by the measurement of ROS and lipid peroxide levels using flow cytometry, as well as the observation of mitochondrial morphology. To analyze the iron-related factors, western blot analysis was employed. The up-regulation of the Nrf2/HO-1 axis was confirmed through various experimental techniques, including CRISPR/Cas9 gene knockout, fluorescent probe staining, and flow cytometry. The efficacy of Z-LIG in inducing ferroptosis was further validated in a xenograft nude mouse model.

RESULTS

Our study revealed that Z-LIG specifically triggered lipid peroxidation-driven cell death in AML cells. Z-LIG downregulated the total protein and nuclear entrance levels of IRP2, resulting in upregulation of FTH1 and downregulation of TFR1. Z-LIG significantly increased the susceptibility to ferroptosis by upregulating ACSL4 levels and simultaneously suppressing the activity of GPX4. Notably, the Nrf2/HO-1 pathway displayed a twofold impact in the ferroptosis induced by Z-LIG. Mild activation suppressed ferroptosis, while excessive activation promoted it, mainly driven by ROS-induced labile iron pool (LIP) accumulation in AML cells, which was not observed in normal human cells. Additionally, Nrf2 knockout and HO-1 knockdown reversed iron imbalance and mitochondrial damage induced by Z-LIG in HL-60 cells. Z-LIG effectively inhibited the growth of AML xenografts in mice, and Nrf2 knockout partially weakened its antitumor effect by inhibiting ferroptosis.

CONCLUSION

Our study presents biological proof indicating that the selective initiation of ferroptosis in leukemia cells is credited to the excessive activation of the Nrf2/HO-1 pathway triggered by Z-LIG.

Examining hepatoprotective effects of astaxanthin against methotrexate-induced hepatotoxicity in rats through modulation of Nrf2/HO-1 pathway genes

Methotrexate (MTX), as a folic acid antagonist, is an effective drug in treating a wide range of malignancies and autoimmune diseases. However, the clinical use of MTX has been limited due to its side effects, the most common of which is hepatotoxicity. In this study, rats were randomly divided into six groups: three treatment groups received methotrexate and different doses of astaxanthin (AX) for 14 days. At the end of the study, blood samples were collected to determine serum levels of ALT, AST, ALP, and LDH. Also, liver tissues were isolated to evaluate antioxidant enzymes and markers of oxidative stress, histopathological damage, and expression of NF-E2-related transcription factor (Nrf2) and Heme oxygenase-1 (HO-1) genes. The results showed that administration of MTX significantly increased the levels of ALT, AST, ALP, and LDH in the blood, markers of oxidative stress, and histopathological damage in liver tissue and significantly reduced the levels of antioxidant enzymes and the expression of Nrf2 and HO-1 genes. On the other hand, treatment with AX decreased blood levels of ALT, AST, ALP, and LDH and oxidative stress markers and remarkably raises the activity of antioxidant enzymes and expression of Nrf2 and HO-1 genes in liver tissue. In addition, histopathological lesions were improved with AX administration. The findings of this study indicated that AX may be useful for the prevention of MTX-induced hepatotoxicity by improving oxidative and inflammatory changes.

Platycodin D inhibits diabetic retinopathy via suppressing TLR4/MyD88/NF-κB signaling pathway and activating Nrf2/HO-1 signaling pathway

Diabetic retinopathy (DR) is one of the most frequently occurring diabetic complications associated with inflammation and oxidative stress. Platycodin D (PLD) is a bio-active saponin that has been reported to exhibit anti-inflammation, anti-oxidative, and antidiabetic activities. Therefore, we speculated the protective effects of PLD on DR in the present study. Our results demonstrated that PLD attenuated high glucose (HG)-induced inflammation, as evidenced by decreased production of TNF-α, IL-1β, IL-6. The HG-induced oxidative stress was prevented by PLD with decreased ROS production and malondialdehyde (MDA) level, as well as increased activities of superoxide dismutase and glutathione (GSH). In addition, treatment of PLD significantly decreased the apoptotic rate in HG-induced ARPE-19 cells. The HG-caused increases in expression of bax and cleaved capsase-3, as well a decrease in bcl-2 expression were attenuated by PLD. Furthermore, PLD suppressed the activation of TLR4/MyD88/NF-κB and enhanced the activation of Nrf2/HO-1 pathway in HG-induced ARPE-19 cells. Additionally, overexpression of TLR4 attenuated the anti-inflammatory, while knockdown of Nrf2 reversed the anti-oxidative and anti-apoptotic activities of PLD in HG-stimulated ARPE-19 cells. Furthermore, PLD attenuates retinal damage in DR rats. Finally, we demonstrated that PLD weakened the TLR4/MyD88/NF-κB p65 pathway and promoted the Nrf2/HO-1 pathway in vivo. Taken together, these findings indicated that PLD exerted protective effects against DR, which were attributed to the regulation of TLR4/MyD88/NF-κB and Nrf2/HO-1 signaling pathways.

The MT1 receptor as the target of ramelteon neuroprotection in ischemic stroke

Stroke is the leading cause of death and disability worldwide. Novel and effective therapies for ischemic stroke are urgently needed. Here, we report that melatonin receptor 1A (MT1) agonist ramelteon is a neuroprotective drug candidate as demonstrated by comprehensive experimental models of ischemic stroke, including a middle cerebral artery occlusion (MCAO) mouse model of cerebral ischemia in vivo, organotypic hippocampal slice cultures ex vivo, and cultured neurons in vitro; the neuroprotective effects of ramelteon are diminished in MT1-knockout (KO) mice and MT1-KO cultured neurons. For the first time, we report that the MT1 receptor is significantly depleted in the brain of MCAO mice, and ramelteon treatment significantly recovers the brain MT1 losses in MCAO mice, which is further explained by the Connectivity Map L1000 bioinformatic analysis that shows gene-expression signatures of MCAO mice are negatively connected to melatonin receptor agonist like Ramelteon. We demonstrate that ramelteon improves the cerebral blood flow signals in ischemic stroke that is potentially mediated, at least, partly by mechanisms of activating endothelial nitric oxide synthase. Our results also show that the neuroprotection of ramelteon counteracts reactive oxygen species-induced oxidative stress and activates the nuclear factor erythroid 2-related factor 2/heme oxygenase-1 pathway. Ramelteon inhibits the mitochondrial and autophagic death pathways in MCAO mice and cultured neurons, consistent with gene set enrichment analysis from a bioinformatics perspective angle. Our data suggest that Ramelteon is a potential neuroprotective drug candidate, and MT1 is the neuroprotective target for ischemic stroke, which provides new insights into stroke therapy. MT1-KO mice and cultured neurons may provide animal and cellular models of accelerated ischemic damage and neuronal cell death.

Bisphenol A induced neuronal apoptosis and enhanced autophagy in vitro through Nrf2/HO-1 and Akt/mTOR pathways

Bisphenol A (BPA) was traditionally used in epoxy resins and polycarbonate plastics, but it was found to be harmful to human health due to its endocrine-disrupting effects. It can affect various biological functions of human beings and interfere with brain development. However, the neurotoxic mechanisms of BPA on brain development and associated neurodegeneration remain poorly understood. Here, we reported that BPA (100, 250, 500 μM) inhibited cell viability of neural cells PC12, SH-SY5Y and caused dose-dependent cell death. In addition, BPA exposure increased intracellular reactive oxygen species (ROS) and mitochondrial ROS (mtROS) levels, decreased mitochondrial membrane potential, reduced the expression of cytochrome c oxidase IV (COX4), downregulated Bcl-2, and initiated apoptosis. Moreover, BPA treatment resulted in the accumulation of intracellular acidic vacuoles and increased the autophagy marker LC3 II to LC3 I ratio. Furthermore, BPA exposure inhibited Nrf2/ HO-1 and AKT/mTOR pathways and mediated cellular oxidative stress, apoptosis, and excessive autophagy, leading to neuronal degeneration. The interactions between oxidative stress, autophagy, and apoptosis during BPA-induced neurotoxicity remain unclear and require further in vivo confirmation.

N-Acetyl-l-cysteine ameliorates gestational diabetes mellitus by inhibiting oxidative stress

Objective: Gestational diabetes mellitus (GDM) affects 7% of pregnant women worldwide. How to effectively treat GDM has always been a concern of people.Research methods: In this study, a diabetes model was established by drug-induced mice. Subsequently, the blood glucose levels and serum insulin changes of the mice after N-acetyl-l-cysteine (NAC) treatment were observed. At the same time, the effect of NAC on reproduction of GDM mice was recorded.Results of the study: Mice fed NAC showed significantly improved glucose tolerance and insulin sensitivity compared to Diabetic/Control. Total serum cholesterol, serum triglycerides, and serum low-density lipoprotein were significantly reduced, and atherosclerosis index was much lower than in control mice. In addition, Diabetic/Control mice had lower litter sizes and higher birth weights. NAC treatment significantly restored litter size and reduced birth weight in Diabetic/Control mice. It was found in WB assay that the NAC-fed group significantly increased nuclear Nrf2 and HO-1 expression levels.Conclusion: NAC can improve blood glucose tolerance in GDM mice; NAC effectively relieves the symptoms of hyperlipidemia caused by GDM; NAC enhances the expression of Nrf2/HO-1 in the liver, thereby restoring redox homeostasis. NAC can reduce gestational diabetes-related disease indicators by oral administration, and has a beneficial effect on the offspring of pregnant mice (reduces its diabetes disease indicators).

Activation of the Nrf-2/HO-1 signalling axis can alleviate metabolic syndrome in cardiovascular disease

Background: Cardiovascular disease (CVD) is widely observed in modern society. CVDs are responsible for the majority of fatalities, with heart attacks and strokes accounting for approximately 80% of these cases. Furthermore, a significant proportion of these deaths, precisely one-third, occurs in individuals under 70. Metabolic syndrome encompasses a range of diseases characterized by various physiological dysfunctions. These include increased inflammation in adipose tissue, enhanced cholesterol synthesis in the liver, impaired insulin secretion, insulin resistance, compromised vascular tone and integrity, endothelial dysfunction, and atheroma formation. These factors contribute to the development of metabolic disorders and significantly increase the likelihood of experiencing cardiovascular complications.Method: We selected studies that proposed hypotheses regarding metabolic disease syndrome and cardiovascular disease (CVD) and the role of Nrf2/HO-1 and factor regulation in CVD research investigations based on our searches of Medline and PubMed.Results: A total of 118 articles were included in the review, 16 of which exclusively addressed hypotheses about the role of Nrf2 on Glucose regulation, while 16 involved Cholesterol regulation. Likewise, 14 references were used to prove the importance of mitochondria on Nrf2. Multiple studies have provided evidence suggesting the involvement of Nrf2/HO-1 in various physiological processes, including metabolism and immune response. A total of 48 research articles and reviews have been used to highlight the role of metabolic syndrome and CVD.Conclusion: This review provides an overview of the literature on Nrf2/HO-1 and its role in metabolic disease syndrome and CVD.

Dimethyl fumarate ameliorates erectile dysfunction in bilateral cavernous nerve injury rats by inhibiting oxidative stress and NLRP3 inflammasome-mediated pyroptosis of nerve via activation of Nrf2/HO-1 signaling pathway

OBJECTIVE

To investigate the therapeutic potential of dimethyl fumarate (DMF) in improving erectile function of bilateral cavernous nerve injury (BCNI) rats, along with elucidating its underlying mechanisms.

METHODS

A BCNI rat model was established by clamping bilateral cavernous nerve (CN). DMF was given by gavage at low (20 mg/kg/day) and high (40 mg/kg/day) dosages for a duration of 4 weeks. Erectile function was assessed by electrical stimulation of CN. Penis and CN tissues were collected for subsequent analysis. Additionally, PC-12 cell line was used to verify the mechanism of DMF in vitro. Nfe2l2 or Ho-1 gene knockdown PC-12 cell lines were constructed by lentiviral transfection, respectively. A damaged cell model was induced using H2O2. And then molecular biological methods were employed to analyze cellular molecules and proteins.

RESULTS

DMF administration for 4 weeks led to improvements in erectile function, reduced fibrosis of penis corpus cavernosum in BCNI rats. The morphology of CN was improved and the number of nerve fibers increased. Furthermore, the levels of nNOS, NO, and cGMP were increased, while Ca2+ was decreased in penis corpus cavernosum. Notably, the levels of ROS, 3-NT and NLRP3 inflammasomes production were reduced, alongside increased expression of Nrf2 and HO-1 proteins in the dorsal penile nerve (DPN) and CN. In vitro, DMF increased cell viability, reduced ROS level, promoted SOD, diminished 3-NT, MDA and DNA damage markers, and inhibited the activation of NLRP3 inflammasomes in H2O2 induced PC-12 cells. Nfe2l2 knockdown and Ho-1 knockdown significantly attenuated the protective effect of DMF, respectively. Furthermore, inhibition of ROS production by N-acetylcysteine led to a reduction in NLRP3 inflammasome activation in H2O2 induced PC-12 cells.

CONCLUSIONS

DMF improved erectile function of BCNI rats by protecting nerves through inhibiting oxidative stress and the activation of NLRP3 inflammasome-mediated pyroptosis via activation of Nrf2/HO-1 pathway.

Mesenchymal stem cells-derived exosomes ameliorate high glucose and lipopolysaccharide-induced HPMECs injury through the Nrf2/HO-1 pathway

Mesenchymal stem cells-derived exosomes (MSC-Exo) are considered to have great potential in the treatment of human diseases. However, the role of MSC-Exo in the process of diabetes with sepsis and the underlying molecular mechanism remain unclear. Human pulmonary microvascular endothelial cells (HPMECs) were treated with high glucose (HG) and lipopolysaccharide (LPS). Cell viability, migration, angiogenesis were analyzed by cell counting kit 8 assay, transwell assay and tube formation assay. Transmembrane electrical resistance (TER) detection and FITC-dextran assay were performed to evaluate cell barrier function. The protein levels of cell permeability-related markers, ferroptosis-related markers, exosomes-related markers, Nrf2 and HO-1 were examined using western bolt (WB) analysis. Besides, the levels of inflammation factors were tested by ELISA, and the levels of ferroptosis-related indicators were examined using corresponding assay kits. Flow cytometry was employed to analyze stem cell markers. The identification of MSC-Exo was performed using transmission electron microscopy, nanoparticle tracking analysis and WB analysis. DIO staining was used to examine the uptake of MSC-Exo by HPMECs. HG treatment suppressed HPMECs viability, migration, angiogenesis and TER, while promoted permeability, inflammation and ferroptosis. LPS treatment aggravated HG-induced HPMECs dysfunction, inflammation and ferroptosis. After HPMECs were co-cultured with MSC-Exo, cell injury induced by HG + LPS could be relieved. Moreover, MSC-Exo treatment enhanced the activity of Nrf2/HO-1 pathway in HG + LPS-induced HPMECs, and Nrf2-silenced MSC-Exo could promote HG + LPS-induced HPMECs injury. MSC-Exo alleviated HG + LPS-induced HPMECs injury via activating Nrf2/HO-1 pathway, confirming that it might be used for the treatment of diabetes with sepsis.

Bioactive dipeptides mitigate high-fat and high-fructose corn syrup diet-induced metabolic-associated fatty liver disease via upregulation of Nrf2/HO-1 expressions in C57BL/6J mice

Metabolic-associated fatty liver disease (MAFLD), formerly referred to as non-alcoholic fatty liver disease (NAFLD), is a common liver disease characterized by an abnormal buildup of fat in liver. This study aimed to investigate whether bioactive dipeptides mitigate high-fat and high-fructose corn syrup diet (HFFD)-induced MAFLD in C57BL/6J mice. Sixty male C57BL/6J mice were randomly divided into six groups. The naïve group (untreated) was fed a standard chow diet and other groups were fed with HFFD along with vehicle and bioactive dipeptides treatment throughout experiment period. The control group received vehicle, YF10 and YF50 groups received Tyr-Phe, 10 and 50 mg/kg/day, FY10 and FY50 groups received Phe-Tyr, 10 and 50 mg/kg/day. At the end of experiment, body weight was recorded, and glucose homeostasis was assessed. Mice were sacrificed and blood samples were collected to measure biochemical parameters. Further, liver, visceral fat pads, and other organs were acutely dissected, weighed, and processed. Histopathological and immunohistochemical changes were analyzed. Long-term HFFD feeding resulted in elevated body weight gain, liver weight, visceral adiposity, liver injury, fasting hyperglycemia, hyperinsulinemia, and hyperlipidemia. It also increased severe hepatic steatosis, chronic low-grade inflammation, oxidative stress, mitochondrial dysfunction, and lipid peroxidation. However, bioactive dipeptides dose-dependently alleviated these complications which are associated with MAFLD by modulating adipokines secretion and antioxidant defense system via upregulation of Nrf2/HO-1 expressions. This study highlights potential of bioactive dipeptides as a promising approach for prevention and/or treatment of MAFLD induced by HFFD, providing novel insights into alternative therapeutic strategies.

Dapagliflozin attenuates the vulnerability to atrial fibrillation in rats with lipopolysaccharide-induced myocardial injury

BACKGROUND

Oxidative stress is an essential component participating in the development and maintenance of atrial fibrillation (AF). Dapagliflozin, a SGLT2 inhibitor, has been shown to exert cardioprotective effects by ameliorating oxidative stress in multiple heart disease models. However, its potential to attenuate lipopolysaccharide (LPS)-induced myocardial injury in rats remains unknown.

AIM

This study aims to investigate the role of dapagliflozin in LPS-induced myocardial injury and the potential mechanisms involved.

METHODS

Rats were intraperitoneally administered LPS to induce sepsis-like condition. The intervention was conducted with intraperitoneal injection of dapagliflozin or saline 1 h in advance. The effects of dapagliflozin were detected by electrophysiological recordings, western blot, qPCR, ELISA, HE staining, immunohistochemistry and fluorescence. We further validated the mechanism in vitro using HL-1 cells.

RESULTS

Dapagliflozin significantly improved LPS-induced myocardial injury, reduced susceptibility to AF, and mitigated atrial tissue inflammatory cell infiltration and atrial myocyte apoptosis. These were correlated with the Nrf2/HO-1 signaling pathway, which subsequently reduced oxidative stress. Subsequently, we used a specific inhibitor of the Nrf2/HO-1 pathway in vitro, reversed the anti-oxidative stress effects of dapagliflozin on HL-1 cells, further confirming the Nrf2/HO-1 pathway's pivotal role in dapagliflozin-mediated cardioprotection.

CONCLUSION

Dapagliflozin ameliorated myocardial injury and susceptibility to AF induced by LPS through anti-oxidative stress, which relied on upregulation of the Nrf2/HO-1 pathway.

Nifuroxazide attenuates indomethacin-induced renal injury by upregulating Nrf2/HO-1 and cytoglobin and suppressing NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals

Indomethacin (INDO) is an NSAID with remarkable efficacy and widespread utilization for alleviating pain. Nevertheless, renal function impairment is an adverse reaction linked to INDO usage. Nifuroxazide (NFX), an oral nitrofuran antibiotic, is frequently employed as an intestinal anti-infective agent. Our study aimed to investigate the renoprotective effects of NFX against INDO-induced nephrotoxicity and explore the protection mechanisms. Four groups of rats were allocated to (I) the normal control, (II) the NFX-treated (50 mg/kg), (III) INDO control (20 mg/kg), and (IV) NFX + INDO. NFX attenuates renal impairment in INDO-induced renal injury, proved by decreasing serum levels of urea, creatinine, uric acid, and NGAL while the albumin was elevated. NFX mitigates renal oxidative stress by decreasing MDA levels and restoring the antioxidants' GSH and SOD levels mediated by upregulating Nrf2, HO-1, and cytoglobin pathways. NFX mitigated renal inflammation and effectively decreased MPO, IL-1β, and TNF-α levels in the rat's kidney mediated by significant downregulation of NADPH-oxidase and NF-κB expression and suppression of JAK-1 and STAT3 phosphorylation. NFX mitigates renal apoptosis by decreasing the expression of cleaved caspase-3 expression. In conclusion, NFX treatment prevents INDO nephrotoxicity by regulating Nrf2/HO-1, cytoglobin, NADPH-oxidase, NF-κB, and JAK-1/STAT3 signals.

HH-A, a modified honokiol, protects against cerebral ischemia/reperfusion induced brain injury in rodent via Nrf2/HO-1 signaling pathways

Honokiol, a bioactive component found in Magnolia officinalis, has shown in protecting against ischemic stroke in animal models. However, its poor water solubility has limited its clinical applications. In this study, we introduced a hydrophilic building block on the aromatic ring of honokiol, resulting in the synthesis of four new compounds (HH-A, -B, -C and -D) with significantly improved water solubility. We then investigated the neuroprotective effects of these compounds in mouse and rat models of transient middle cerebral artery occlusion/reperfusion (tMCAO/R) brain injury. Among the compounds tested, HH-A, also known as (S)-6-((3',5-diallyl-2,4'-dihydroxy-[1,1'-biphenyl]-3-yl)amino)-6-oxohexane-1,5-diaminium chloride, showed the most promising results. HH-A was found to significantly reduced the infarct volume and brain edema in mice. It also outperformed the other three compounds and honokiol, even surpassing the effects of edaravone dexborneol. Additionally, HH-A demonstrated dose-dependent improvements in body weight, neurological deficits, and infarct volume. Further analysis in tMCAO/R rat model revealed that HH-A treatment led to significant upregulations of Nrf2 and HO-1 in the brain. HH-A also significantly reduced the expression of HNE, and exhibited anti-apoptotic effects by decreasing the expression of Bax and increasing the expression of Bcl-2. This was further supported by a decrease in the number of TUNEL positive cells. Taken together, the neuroprotective effects of HH-A may be attributed to its ability to target the Nrf2/HO-1 signaling pathway, leading to reduced oxidative stress and apoptosis in the brain. These findings suggest that HH-A has potential as a therapeutic agent for the treatment of ischemic stroke.

Anthocyanins Inhibits Oxidative Injury in Human Retinal Pigment Epithelial ARPE-19 Cells via Activating Heme Oxygenase-1

Anthocyanins belong to phenolic pigments and are known to have various pharmacological activities. This study aimed to investigate whether anthocyanins could inhibit hydrogen peroxide (H2O2)-induced oxidative damage in human retinal pigment epithelial ARPE-19 cells. Our results indicated that anthocyanins suppressed H2O2-induced genotoxicity, while inhibiting reactive oxygen species (ROS) production and preserving diminished glutathione. Anthocyanins also suppressed H2O2-induced apoptosis by reversing the Bcl-2/Bax ratio and inhibiting caspase-3 activation. Additionally, anthocyanins attenuated the release of cytochrome c into the cytosol, which was achieved by interfering with mitochondrial membrane disruption. Moreover, anthocyanins increased the expression of heme oxygenase-1 (HO-1) as well as its activity, which was correlated with the phosphorylation and nuclear translocation of nuclear factor-erythroid-2 related factor 2 (Nrf2). However, the cytoprotective and anti-apoptotic effects of anthocyanins were significantly attenuated by the HO-1 inhibitor, demonstrating that anthocyanins promoted Nrf2-induced HO-1 activity to prevent ARPE-19 cells from oxidative stress. Therefore, our findings suggest that anthocyanins, as Nrf2 activators, have potent ROS scavenging activity and may have the potential to protect ocular injury caused by oxidative stress.

Sugarcane leaf polysaccharide exerts a therapeutic effect on cardiovascular diseases through necroptosis

Background

Necroptosis, a novel form of programmed cell death wherein the necrotic morphology is characterized by swelling of the cells, rupture of the plasma membrane, and dysfunction of the organelle, has been always observed in cardiovascular diseases. Sugarcane leaf polysaccharide (SLP) are primary components present in sugarcane leaves that exert cardiovascular protective effects. However, the positive effect of SLP and underlying mechanisms in myocardial ischemia-reperfusion (MI/R) remain unexplored.

Aim

In this study, the protective effects of SLP on MI/R injury were investigated under in vitro and in vivo conditions.

Methods

The protective effects of SLP on MI/R injury were assessed using tertiary butyl hydrogen peroxide (TBHP)-stimulated-H9c2 cells in the in vitro assay and using Sprague Dawley rats in the in vivo assay.

Results

In vitro, SLP significantly reversed TBHP-induced H9c2 cell death by inhibiting necroptosis and oxidative stress. SLP exerted antioxidant activity through the Nrf2/HO-1 pathway. SLP suppressed necroptosis by decreasing phosphorylation of RIP1, RIP3, and MLKL in TBHP-stimulated H9c2 cells. In vivo, SLP attenuated MI/R injury by decreasing the myocardial infarct area; increasing myeloperoxidase and superoxide dismutase levels; and reducing malondialdehyde, interleukin-6, and tumor necrosis factor-α levels.

A Study of Gentianae Radix et Rhizoma Class Differences Based on Chemical Composition and Core Efficacy

(1) Background: Establishment of a method for evaluating Gentianae Radix et Rhizoma (GRR) classes based on chemical composition and core efficacy; (2) Methods: Liquid chromatography-mass spectrometry (LC-MS) was used to determine the chemical constituents of GRR-first class (GF) and GRR-second class (GS). The cell viability, liver function, oxidative stress enzyme activity, and inflammatory factor levels of GF and GS on H2O2-induced HepG2 cells were determined with CCK-8, ELISA, and biochemical methods, and the antioxidant activity of the two was evaluated using bioefficacy; ELISA, biochemical methods, real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) method, and Western blot (WB) were used to determine the liver function, oxidative stress enzyme activity, inflammatory factor levels, and expression of related genes and proteins in mice with acute liver injury (ALI) model induced with 0.3% CCl4 olive oil solution after gavage administration; (3) Results: GF and GS had the same types of components, but the cyclic enol ether terpenes such as morinlon goside c, loganin, gentiopicroside, and swertiamarin differed significantly between the two; the effect of GF on CCl4-induced acute hepatic injury in C57BL/6 mice was stronger compared to GS. It helped alleviate weight loss, increase hepatic and splenic indices, improve hepatic lobular structure and hepatocyte status, inhibit collagen deposition, enhance oxidative stress and anti-inflammatory-related genes and protein expression, and decrease apoptotic genes and proteins more significantly than GS; (4) Conclusions: In this study, we established a GRR class evaluation method combining chemical composition and core medicinal effects, which can rapidly determine the differential composition of GF and GS, detect the quality of GRR through antioxidant bioefficacy, and validate it with in vivo experiments, which provides references for the evaluation of the class of GRR and the rational use of medication in the clinic.

Nrf2/HO-1 blocks TXNIP/NLRP3 interaction via elimination of ROS in oxygen-glucose deprivation-induced neuronal necroptosis

Acute ischemic stroke (AIS) is known to trigger a cascade of inflammatory events that induces secondary tissue damages. As a type of regulated inflammatory cell death, necroptosis is associated with AIS, whilst its regulation during neuroinflammation is not well understood. In particular, the actual function of NOD-like-receptor family pyrin domain-containing-3(NLRP3) inflammasome in cortical neuronal necroptosis still not clear. Herein, we explored the function of nuclear factor erythroid-2 related factor-2 (Nrf2)/heme oxygenase-1 (HO-1) in oxygen-glucose deprivation (OGD) induced neuronal necroptosis and its underlying mechanism. To establish an in vitro model of neuronal necrosis, we used OGD/caspase-8 inhibitors (Q-VD-OPh, QVD) to treat rat primary cortical neurons (PCNs) after reoxygenation, wherein we found that the model cause an elevated ROS levels by mediating TXNIP/NLRP3 interactions, which in turn activated the NLRP3 inflammasome. Also, we observed that regulation of nuclear factor erythroid-2 related factor-2 (Nrf2) promoted heme oxygenase-1 (HO-1) expression and decreased TXNIP (a protein that relate oxidative stress to activation of inflammasome) and ROS levels, which negatively regulated the expression of OGD-induced activation of NLRP3 inflammasomes. In addition, HO-1 weakened NLRP3 inflammation body activation, which suggests that Nrf2-regulated HO-1 could block the interaction between TXNIP and NLRP3 in OGD/R-treated cortical neurons by inhibiting ROS production. Our study has discovered the importance of Nrf2/HO-1 signaling cascade for inhibiting inflammasome of NLRP3, which negatively regulated necrosis. Therefore, NLRP3 is considered a potential target for a novel neuroprotective approach, which can expand the therapeutic windows of stroke drugs.

Lansoprazole attenuates cyclophosphamide-induced cardiopulmonary injury by modulating redox-sensitive pathways and inflammation

Cyclophosphamide (CPA) is a classical chemotherapeutic drug widely used as an anticancer and immunosuppressive agent. However, it is frequently associated with significant toxicities to the normal cells of different organs, including the lung and heart. Lansoprazole (LPZ), a proton pump inhibitor (PPI), possesses antioxidant and anti-inflammatory properties. The current study investigated how LPZ protects against CPA-induced cardiac and pulmonary damage, focusing on PPARγ, Nrf2, HO-1, cytoglobin, PI3K/AKT, and NF-κB signaling. Animals were randomly assigned into four groups: normal control group (received vehicle), LPZ only group (Rats received LPZ at a dose of 50 mg/kg/day P.O. for 10 days), CPA group (CPA was administered (200 mg/kg) as a single i.p. injection on the 7th day), and cotreatment group (LPZ plus CPA). Histopathological and biochemical analyses were conducted. Our results revealed that LPZ treatment revoked CPA-induced heart and lung histopathological alterations. Also, LPZ potently mitigated CPA-induced cardiac and pulmonary oxidative stress through the activation of PPARγ, Nrf2/HO-1, cytoglobin, and PI3K/AKT signaling pathways. Also, LPZ effectively suppressed inflammatory response as evidenced by down-regulating the inflammatory strategic controller NF-κB, MPO, and pro-inflammatory cytokines. The present findings could provide a mechanistic basis for understanding LPZ's role in CPA-induced cardiopulmonary injury through the alleviation of oxidative stress and inflammatory burden.

A low dose of naloxone mitigates autoimmune hepatitis by regulating TLR4/NF-κB and Nrf2/HO-1 signaling pathways

Naloxone is a non-selective opiate receptor antagonist that is mainly used in the management of acute opioid overdose or intoxication. Previously, naloxone has been shown to have anti-inflammatory and antioxidant properties. Concanavalin A (Con A) model is a common and well established animal model of autoimmune hepatitis that closely resembles the pathological alterations that occur in human. The present study demonstrates that a low dose of naloxone (LD NX) has the ability to improve hepatic function and attenuate hepatic damage induced by Con A as indicated by a clear reduction in serum aminotransferase, bilirubin and enhancement of albumin production as well as liver pathological changes. Also, The proinflammatory cytokines, tumor necrosis factor-α (TNF-α), interferon- γ (IFN-γ), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were highly suppressed in animals pretreated with LD NX via interference with TLR4/NF-κB as well as JNK signaling pathways. Furthermore, oxidative stress was highly attenuated in animals pretreated with LD NX as indicated by high reduction in hepatic MDA and an increase in Nrf2, HO-1 expression and subsequent production of the endogenous antioxidants, SOD, CAT and GSH. Collectively, this study demonstrates that LD NX has the ability to mitigate Con A-induced autoimmune hepatitis via modulation of inflammatory cytokines secretion and interference with reactive oxygen species generation.

Ferrostatin-1 facilitated neurological functional rehabilitation of spinal cord injury mice by inhibiting ferroptosis

BACKGROUND

To seek the potential therapy for spinal cord injury, Ferrostatin-1, the first ferroptosis inhibitor, was administrated in spinal cord injury mice to identify the therapeutic effect.

METHODS

Spinal cord injury model was established by a modified Allen's method. Then, ferrostatin-1 was administrated by intraspinal injection. Cortical evoked motor potential and BMS were indicated to assess the neurological function rehabilitation. H&E, Nissl's staining, NeuN, and GFAP immunofluorescence were used to identify the histological manifestation on the mice with the injured spinal cord. Spinosin, a selective small molecule activator of the Nrf2/HO-1 signaling pathway, was administrated to verify the underlying mechanism of ferrostatin-1.

RESULTS

Ferrostatin-1 promoted the rehabilitation of cortical evoked motor potential and BMS scores, synchronized with improvement in the histological manifestation of neuron survival and scar formation. Spinosin disturbed the benefits of ferrostatin-1 administration on histological and neurobehavioral manifestation by deranging the Nrf2/HO-1 signaling pathway.

CONCLUSIONS

Ferrostatin-1 improved the rehabilitation of spinal cord injury mice by regulating ferroptosis through the Nrf2/HO-1 signaling pathway.

Catalpol ameliorates inflammation and oxidative stress via regulating Sirt1 and activating Nrf2/HO-1 signaling against acute kidney injury

BACKGROUND

Septic acute kidney injury (SAKI) is usually caused by sepsis. It has been shown that catalpol (Cat) impairs sepsis-evoked organ dysfunction to a certain degree. The current work aims to evaluate the protective effects of Cat on SAKI and potential mechanisms in vivo and in vitro.

METHODS

SAKI cellular and murine model were set up using lipopolysaccharide (LPS) in vitro and in vivo. Cell apoptosis in cells was determined by TUNEL assay. Levels of inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). The levels of the markers of oxidative injury were evaluated by corresponding commercial kits. Protein levels were assayed via western blotting and immunohistochemistry (IHC) staining.

RESULTS

The results demonstrated that LPS upregulated TNF-α, IL-6, and malondialdehyde levels, and downregulated superoxide dismutase, whereas Cat treated cells have the opposite results. Functional assays displayed that Cat remarkably reversed the LPS-challenged damage as the impairment of TNF-α and IL-6 levels, oxidative stress, and the apoptosis in HK-2 cells. Moreover, knockdown of Sirtuin 1 (Sirt1) counteracted the suppressive impact of Cat on LPS-triggered inflammatory response, oxidative stress, and renal damage. Further, Cat elevated Sirt1 expression and activated the Nrf2/HO-1 signaling in LPS-engendered SAKI in vivo and in vitro.

CONCLUSION

Our study clearly proved that Cat protected against LPS-induced SAKI via synergic antioxidant and anti-inflammatory actions by regulating Sirt1 and Nrf2/HO-1 signaling pathways.

Paeoniflorin alleviates AngII-induced cardiac hypertrophy in H9c2 cells by regulating oxidative stress and Nrf2 signaling pathway

Cardiac hypertrophy is frequently associated with ventricular dysfunction and heart failure. Paeoniflorin, has been widely used to treat cardiovascular dysfunction-related diseases. However, the underlying mechanism has been unclear. Here, we investigated the potential inhibitory effects and mechanism of paeoniflorin on oxidative stress of cardiac hypertrophy induced by angiotensin II (AngII) in vitro. Using MTS assay, qRT-PCR, WGA staining assay, and western blot, different dosages (50-400 μM) of paeoniflorin were utilized to examine the antihypertrophy effects on H9c2 cells. Western blot examination revealed the presence of apoptosis-related proteins Bax, Bcl2, and Cytc, antioxidative stress-related proteins Nrf2, HO-1, SOD, and CAT, and mitophagy-related proteins PINK1 and Parkin. qRT-PCR was used to detect the mRNA expression of Bax, Bcl2, Nrf2, and HO-1. TUNEL, caspase3/9 enzyme viability, and MDA, T-AOC, and superoxide levels were all evaluated using commercial kits.The fluorescent probes DCFH-DA and JC-1 were employed to measure cellular ROS and MMP levels. Nrf2 siRNA was utilized to investigate Nrf2's role in paeoniflorin-treated cardiac hypertrophy. Paeoniflorin dramatically reduced cell section area (CSA) and hypertrophic marker (ANP, BNP) expression while inhibiting oxidative stress by modulating ROS and MDA, CAT, SOD, and T-AOC levels. Furthermore, in AngII-induced cardiomyocyte hypertrophy, paeoniflorin restores H9c2 apoptosis by restoring Bax, Bcl-2 Cyt-C, Caspase 3, and Caspase 9 levels. Paeoniflorin also restored Nrf2/HO-1 and PINK1/Parkin expression, and its anti-AngII activities were mediated by Nrf2, which was regulated by Nrf2 knockdown. In conclusion, Our data confirm that paeoniflorin alleviates cardiac hypertrophy through modulating oxidative stress and Nrf2 signaling pathway in vitro.

Buspirone attenuated methotrexate-induced hippocampal toxicity in rats by regulating Nrf2/HO-1, PPAR-γ, NF-κB/nNOS, and ROS/NLRP3/caspase-1 signaling pathways

Methotrexate (MTX) is a chemotherapeutic agent widely used to treat a variety of tumors. Nonetheless, MTX-induced hippocampal neurotoxicity is a well-defined dose-limiting adverse effect that limits clinical utility. Proinflammatory cytokine production and oxidative stress are possible mechanisms for MTX-induced neurotoxicity. Buspirone (BSP), a partial agonist of the 5-HT1a receptor (5-HT1aR), has emerged as an anxiolytic drug. BSP has been shown to possess antioxidant and anti-inflammatory effects. The current study investigated BSP's potential anti-inflammatory and antioxidant effects in attenuating MTX-induced hippocampal toxicity. Rats received either BSP (1.5 mg/kg) orally for 10 days and MTX (20 mg/kg) i.p. on Day 5. BSP administration markedly protected hippocampal neurons from drastic degenerated neuronal changes induced by MTX. BSP significantly attenuated oxidative injury by downregulating Kelch-like ECH-associated protein 1 expression while potently elevating hippocampal Nrf2, heme oxygenase-1, and peroxisome proliferator-activated receptor expression. BSP dampened inflammation by reducing NO2 - , tumor necrosis factor-alpha, IL-6, and interleukin 1 beta levels mediated by downregulating NF-κB and neuronal nitric oxides synthase expression. Moreover, BSP potently counteracted hippocampal pyroptosis by downregulating NLRP3, ASC, and cleaved-caspase-1 proteins. Therefore, BSP may represent a promising approach to attenuate neurotoxicity in patients receiving MTX.

Quercetin Alleviated Inflammasome-Mediated Pyroptosis and Modulated the mTOR/P70S6/P6/eIF4E/4EBP1 Pathway in Ischemic Stroke

Stroke ranks as the world's second most prevalent cause of mortality, and it represents a major public health concern with profound economic and social implications. In the present study, we elucidated the neuroprotective role of quercetin on NLRP3-associated pyroptosis, Nrf2-coupled anti-inflammatory, and mTOR-dependent downstream pathways. Male Sprague Dawley rats were subjected to 72 h of transient middle cerebral artery ischemia, followed by the administration of 10 mg/kg of quercetin. Our findings demonstrated that MCAO induced elevated ROS which were coupled to inflammasome-mediated pyroptosis and altered mTOR-related signaling proteins. We performed ELISA, immunohistochemistry, and Western blotting to unveil the underlying role of the Nrf2/HO-1 and PDK/AKT/mTOR pathways in the ischemic cortex and striatum. Our results showed that quercetin post-treatment activated the Nrf2/HO-1 cascade, reversed pyroptosis, and modulated the autophagy-related pathway PDK/AKT/mTOR/P70S6/P6/eIF4E/4EBP1. Further, quercetin enhances the sequestering effect of 14-3-3 and reversed the decrease in interaction between p-Bad and 14-3-3 and p-FKHR and 14-3-3. Our findings showed that quercetin exerts its protective benefits and rescues neuronal damage by several mechanisms, and it might be a viable neuroprotective drug for ischemic stroke therapy.

[Acetaldehyde dehydrogenase 2 ameliorates lung endothelial barrier and balances mitochondrial dynamics in mice with acute lung injury]

OBJECTIVE

To investigate the protective effects of acetaldehyde dehydrogenase 2 (ALDH2) against lipopolysaccharide (LPS)- induced acute lung injury (ALI) in mice and explore the possible mechanisms.

METHODS

Sixty C57BL/6J mice were equally randomized into Sham group, LPS group, LPS + Alda-1 (an ALDH2 agonist) group, and LPS + Daidzin (an ALDH2 inhibitor) group. After the treatment, the wet/dry lung mass ratio of the mice was measured, and the lung permeability was evaluated with Evans Blue (EB). The lung tissue pathologies were evaluated with HE staining and transmission electron microscopy. Serum levels of 4-hydroxynonenal (4-HNE) were measured with ELISA, and malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) levels were determined to measure oxidative stress levels. The expressions of ALDH2, ZO-1, Occludin, Mfn2, OPA1, Drp1, Fis1, and nuclear Nrf2 and HO-1 proteins in the lung tissues were detected using Western blotting.

RESULTS

The mice with LPS-induced ALI showed severe disruption of the lung tissue structure and endothelial cell tight junctions with significantly increased the lung permeability (P<0.01), increased levels of 4-HNE and MDA (P<0.01), decreased activities of CAT and SOD (P<0.01), lowered expressions of ALDH2, ZO-1, Occludin, Mfn2, and OPA1 proteins, and increased expressions of Drp1, Fis1, and nuclear Nrf2 and HO-1 proteins (P<0.05, P<0.01). Treatment with Alda-1 significantly improved lung tissue pathologies and mitochondrial damage in ALI mice (P<0.01), increased the expressions of ALDH2, ZO-1, Occludin, OPA1, Mfn2, and nuclear Nrf2 and HO-1 proteins, and lowered the expressions of Drp1 and Fis1 proteins (P<0.05, P<0.01). Compared with Alda-1, treatment with Daidzin significantly increased the lung permeability, exacerbated mitochondrial damage, decreased the expression of ALDH2, ZO-1, Occludin, Mfn2, OPA1, and nuclear Nrf2 and HO-1 proteins, and increased expressions of Drp1 and Fis1 proteins (P<0.05, P<0.01).

CONCLUSION

ALDH2 can ameliorate LPSinduced lung endothelial barrier damage in ALI mice by maintaining the balance of mitochondrial dynamics and inhibiting oxidative stress, and the mechanism may be related to the Nrf2/HO-1 pathway.

Neuroprotective effects of Lycium barbarum polysaccharide on light-induced oxidative stress and mitochondrial damage via the Nrf2/HO-1 pathway in mouse hippocampal neurons

Light at night (LAN) induced cognitive impairment associated with oxidative stress in mice has been reported. Lycium barbarum polysaccharide (LBP) exhibits anti-tumor, anti-oxidant and neuroprotective effects, yet the neuroprotective effect on light-induced neuron damage still unclear. Here, mice exposed to LAN displayed cognitive impairment and depressive like behavior, which was reversed by LBP treatment. Meanwhile, LBP alleviated light-induced higher apoptosis and mitochondrial damage in HT-22 cells. Also, LBP prevented the decreased of mitochondrial membrane permeabilization (MMP) level in light-treated cells. Additionally, LBP demonstrated its antioxidant potential by reducing ROS production and malondialdehyde (MDA) level, while simultaneously enhancing the levels of superoxide dismutase (SOD) and glutathione peroxidases (GSH-Px) in both light-treated mice and HT-22 cells. Furthermore, the mRNA and protein expression of Nrf2 (NF-E2-related factor 2), heme oxygenease-1 (HO-1), and NAD(P)H quinone oxidoreductase (NQO1) were decreased in both light-treated mice and cells. Additionally, LBP treatment reversed light-induced the inhibition of Nrf2/HO-1 signaling pathway in both mice and cells. Moreover, Nrf2 antagonist ML385 significantly eliminated the neuroprotection of LBP on cell apoptosis, oxidative stress and mitochondrial damage in light-treated cells. These results indicate that LBP can rescue light-induced neurotoxicity in mice and HT-22 cells by activating the Nrf2/HO-1 signaling pathway.

ETS1 Ameliorates Hyperoxia-Induced Bronchopulmonary Dysplasia in Mice by Activating Nrf2/HO-1 Mediated Ferroptosis

PURPOSE

Bronchopulmonary dysplasia (BPD) is associated with hyperoxia-induced oxidative stress-associated ferroptosis. This study examined the effect of E26 oncogene homolog 1 (ETS1) on oxidative stress-associated ferroptosis in BPD.

METHODS

Hyperoxia-induced A549 cells and neonatal mice were used to establish BPD models. The effects of ETS1 on hyperoxia-induced ferroptosis-like changes in A549 cells were investigated by overexpression of ETS1 plasmid transfection and erastin treatment. Glucose consumption, lactate production, and NADPH levels were assessed by the glucose, lactate, and NADP+/NADPH assay kits, respectively. The potential regulatory relationship between ETS1 and Nrf2/HO-1 was examined by treating hyperoxia-induced A549 cells with the Nrf2 inhibitor ML385. ETS1 effect on the Nrf2 promoter was explored by dual-luciferase reporter and chromatin immunoprecipitation assay. The effect of ETS1 on the symptoms of BPD mice was examined by injecting an adenovirus overexpressing ETS1.

RESULTS

ETS1 overexpression increased hyperoxia-induced cell viability, glucose consumption, lactate production, and NADPH levels and reduced inflammation and apoptosis in A549 cells. In animal experiments, ETS1 overexpression prevented weight loss, airway enlargement, and reductions in radial alveolar counts in BPD mice, while reducing the mean linear intercept, mean alveolar diameter and inflammation. ETS1 overexpression suppressed PTGS2 and CHAC1 expression, reduced ROS, MDA and ferrous iron (Fe2+) production and increased GSH levels in hyperoxia-induced A549 cells and BPD mice. In addition, ETS1 can bind to the Nrf2 promoter region and thus promote Nrf2 transcription. ETS1 overexpression increased the mRNA and protein levels of Nrf2, HO-1, xCT, and GPX4 in hyperoxia-induced A549 cells and BPD mice. In hyperoxia-induced A549 cells, erastin and ML385 treatment abolished the effect of ETS1 overexpression.

CONCLUSION

ETS1 is important in oxidative stress-related ferroptosis in a hyperoxia-induced BPD model, and the effect is partially mediated by the Nrf2/HO-1 axis.

Myricetin Protects Against Rat Intervertebral Disc Degeneration Partly Through the Nrf2/HO-1/NF-κB Signaling Pathway

Intervertebral disc (IVD) degeneration (IDD) is a prevalent musculoskeletal disorder. Nucleus pulposus cells (NPCs) play a significant role in the normal functioning of the IVD. Myricetin is an agent that exerts anti-inflammatory and antioxidant effects in various pathological conditions. Here, we investigated the ameliorative effects of myricetin on the IVD degeneration. NPCs were obtained from the IVD of rats, and were treated with myricetin (0, 5, 10, 15, 20 μM) for 24 h before 20 ng/mL IL-1β stimulation. RT-qPCR, western blotting, and ELISA were applied to evaluate the levels of inflammatory factors (iNOS, COX-2, TNF-α, IL-6, PGE2, and Nitrite) and extracellular matrix (ECM)-associated components (MMP13, ADAMTS-5, aggrecan, and collagen II) in NPCs. Activation status of related signaling pathways (NF-κB and Nrf2) was determined using western blotting and immunofluorescence staining. Experimental rat models of IDD were established using a needle puncture method. Myricetin (20 mg/kg) was administrated intraperitoneally, and the degeneration was evaluated using histopathological analysis. Myricetin treatment attenuated the IL-1β-induced production of inflammatory factors in NPCs. Downregulation of aggrecan and collagen II as well as upregulation of MMP-13 and ADAMTS-5 in NPCs caused by IL-1β was reversed by myricetin treatment. Mechanistically, myricetin blocked NF-κB signaling by activation of Nrf2 in IL-1β-stimulated NPCs. Moreover, inhibition of Nrf2 reversed the protective effects of myricetin in NPCs. The in vivo experiments showed that myricetin ameliorated the IDD progression in rats. The present work suggests that Nrf2 is involved in the pathogenesis of IDD and shows the protective effects as well as the underlying mechanism of myricetin on Nrf2 activation in NPCs.

Opioids Alleviate Oxidative Stress via the Nrf2/HO-1 Pathway in LPS-Stimulated Microglia

Opioids are known to have antioxidant effects and to modulate microglial function under certain conditions. It has been previously shown that opioid ligands can effectively inhibit the release of proinflammatory cytokines when stimulated with lipopolysaccharide (LPS) and convert microglia to an anti-inflammatory polarization state. Here, we used C8-B4 cells, the mouse microglial cell line activated by LPS as a model to investigate the anti-inflammatory/antioxidant potential of selected opioid receptor agonists (DAMGO, DADLE, and U-50488). We found that all of these ligands could exert cytoprotective effects through the mechanism affecting LPS-induced ROS production, NADPH synthesis, and glucose uptake. Interestingly, opioids elevated the level of reduced glutathione, increased ATP content, and enhanced mitochondrial respiration in microglial cells exposed to LPS. These beneficial effects were associated with the upregulation of the Nrf2/HO-1 pathway. The present results indicate that activation of opioid signaling supports the preservation of mitochondrial function with concomitant elimination of ROS in microglia and suggest that an Nrf2/HO-1 signaling pathway-dependent mechanism is involved in the antioxidant efficacy of opioids. Opioid receptor agonists may therefore be considered as agents to suppress oxidative stress and inflammatory responses of microglia.

Protective effects of aloin on asthmatic mice by activating Nrf2/HO-1 pathway and inhibiting TGF-β/Smad2/3 pathway

BACKGROUND

Asthma is a severe chronic respiratory disease affecting all age groups with increasing prevalence. Anti-inflammatory strategies are promising options for the treatment of asthma. Although the inhibitory effect of aloin on inflammation has been demonstrated in various diseases, its effect on asthma remains unknown.

METHODS

A mice asthma model was established by treating with ovalbumin (OVA). The effects and mechanism of aloin on the OVA-treated mice were determined by enzyme-linked--immunosorbent serologic assay, biochemical examination, hematoxylin and eosin and Masson's staining, and Western blot assay.

RESULTS

OVA treatment in mice significantly increased the number of total cells, neutrophils, eosinophils, and macrophages and the concentration of interleukin (IL)-4, IL-5, and IL-13, which were attenuated with the administration of aloin. The content of malondialdehyde was enhanced in OVA-treated mice, with the decreased levels of superoxide dismutase and glutathione, which were reversed with aloin treatment. Aloin treatment reduced the airway resistance of OVA-induced mice. The inflammatory cell infiltration around small airways was accompanied by the thickening and contraction of bronchial walls and pulmonary collagen deposition in OVA-treated mice; however, these conditions were ameliorated with aloin treatment. Mechanically, aloin upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2)-heme oxygenase 1 (HO-1) pathway but inhibited the level of transforming growth factor beta-SMAD2/3 genes (TGF-β/Smad2/3) axis in OVA-induced mice.

CONCLUSION

Aloin treatment lessened airway hyperresponsiveness, airway remodeling, inflammation, and oxidative stress in OVA-treated mice, and was closely related to the activation of Nrf2/HO-1 pathway and the weakening of TGF-β/Smad2/3 pathway.

Valuable effects of lactobacillus and citicoline on steatohepatitis: role of Nrf2/HO-1 and gut microbiota

Non-alcoholic steatohepatitis (NASH) is a more dangerous form of chronic non-alcoholic fatty liver disease (NAFLD). In the current investigation, the influence of citicoline on high-fat diet (HFD)-induced NASH was examined, both alone and in combination with Lactobacillus (probiotic). NASH was induced by feeding HFD (10% sugar, 10% lard stearin, 2% cholesterol, and 0.5% cholic acid) to rats for 13 weeks and received single i.p. injection of streptozotocin (STZ, 30 mg/kg) after 4 weeks. Citicoline was given at two dose levels (250 mg and 500 mg, i.p.) at the beginning of the sixth week, and in combination with an oral suspension of Lactobacillus every day for eight weeks until the study's conclusion. HFD/STZ induced steatohepatitis as shown by histopathological changes, elevated serum liver enzymes, serum hyperlipidemia and hepatic fat accumulation. Moreover, HFD convinced oxidative stress by increased lipid peroxidation marker (MDA) and decreased antioxidant enzymes (GSH and TAC). Upregulation of TLR4/NF-kB and the downstream inflammatory cascade (TNF-α, and IL-6) as well as Pentaraxin, fetuin-B and apoptotic markers (caspase-3 and Bax) were observed. NASH rats also had massive increase in Bacteroides spp., Fusobacterium spp., E. coli, Clostridium spp., Providencia spp., Prevotella interrmedia, and P. gingivalis while remarkable drop in Bifidobacteria spp. and Lactobacillus spp. Co-treatment with citicoline alone and with Lactobacillus improve histopathological NASH outcomes and reversed all of these molecular pathological alterations linked to NASH via upregulating the expression of Nrf2/HO-1 and downregulating TLR4/NF-kB signaling pathways. These results suggest that citicoline and lactobacillus may represent new hepatoprotective strategies against NASH progression.

Wei-Tong-Xin ameliorated cisplatin-induced mitophagy and apoptosis in gastric antral mucosa by activating the Nrf2/HO-1 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Wei-Tong-Xin (WTX) originated from the famous ancient Chinese formula "Wan Ying Yuan", recorded in the ancient Chinese medicine book "Zhong Zang Jing" by Hua Tuo. As "Jun" drugs, Dahuang and Muxiang have the effects of clearing heat and expelling fire, reducing food retention, regulating Qi and relieving pain. As "Chen" drug, Qianniuzi has the effect of assisting "Jun" drugs. Zhuyazao and Gancao, as "Zuo-Shi" drugs, can reduce toxicity and modulate the medicinal properties of other herbs.

AIM OF THE STUDY

The present study aimed to investigate the effect and mechanism of WTX on the oxidative stress of gastric antrum mucosa in mice with cisplatin (CIS)-induced dyspepsia.

MATERIALS

AND.

METHODS

A variety of experimental methods, including western blot, qRT-PCR, immunofluorescence and immunohistochemistry were performed in vivo and in vitro.

RESULTS

In vivo, WTX restored the number and function of interstitial cells of Cajal (ICCs), accompanied by the inhibition of lipid peroxidation. Moreover, WTX inhibited the activation of Parkin-dependent mitophagy and apoptosis. In vitro, WTX activated the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway and inactivated mitophagy in GES-1 cells. To explore the role of Nrf2 in WTX's improvement of CIS-induced cell damage, Nrf2 inhibitor ML385 was used in cell experiments. We found that ML385 counteracted the regulation of WTX on mitophagy and apoptosis. Finally, N-acetylcysteine (NAC), a reactive oxygen species (ROS) scavenger, was applied in our experiments, and the results suggested that WTX suppressed the CIS-induced apoptosis via mitochondrial pathway.

CONCLUSIONS

The above results, for the first time, indicated that WTX inhibited mitophagy and apoptosis of gastric antral mucosal cells induced by CIS through the Nrf2/HO-1 signaling pathway.

Suramin ameliorates osteoarthritis by acting on the Nrf2/HO-1 and NF-κB signaling pathways in chondrocytes and promoting M2 polarization in macrophages

Osteoarthritis (OA)-the most prevalent of arthritis diseases-is a complicated pathogenesis caused by cartilage degeneration and synovial inflammation. Suramin has been reported to enhance chondrogenic differentiation. However, the therapeutic effect of suramin on OA-induced cartilage destruction has remained unclear. Suramin is an anti-parasitic drug that has potent anti-purinergic properties. This study investigated the protective effects and underlying mechanisms of suramin on articular cartilage degradation using an in vitro study and mice model with post-traumatic OA. We found that suramin markedly suppressed the IL-1β increased expression of matrix destruction proteases-such as ADAMT4, ADAMTS5, MMP3, MMP13, and inflammatory mediators-including the iNOS, COX2, TNFα, and IL-1β; while greatly enhancing the synthesis of cartilage anabolic factors-such as COL2A1, Aggrecan and SOX9 in IL-1β-induced porcine chondrocytes. In vivo experiments showed that intra-articular injection of suramin ameliorated cartilage degeneration and inhibited synovial inflammation in an anterior cruciate ligament transection (ACLT)-induced OA mouse model. In mechanistic studies, we found that exogenous supplementation of suramin can activate Nrf2, and accordingly inhibit the nuclear factor kappa-light-chain-enhancer of activated B cells (NF- κB) and mitogen-activated protein kinase (MAPK) pathways, thereby alleviating the inflammation and ECM degeneration of chondrocytes stimulated by IL-1β. In addition, suramin also repolarized M1 macrophages to the M2 phenotype, further reducing the apoptosis of chondrocytes. Collectively, the results of the study suggests that suramin is a potential drugs which could serve as a facilitating drug for the application of OA therapy toward clinical treatment.

Levetiracetam attenuates experimental ulcerative colitis through promoting Nrf2/HO-1 antioxidant and inhibiting NF-κB, proinflammatory cytokines and iNOS/NO pathways

Ulcerative colitis (UC) is a serious inflammatory disease of the colon. The pathogenic mechanisms of UC involve the activation of inflammatory and oxidative stress responses in the colon. Levetiracetam is an antiepileptic drug with anti-inflammatory and antioxidant effects. The aim of this study was to investigate the potential protective effect of levetiracetam against UC in a mouse model. UC was induced in mice by intrarectal administration of acetic acid and then mice were treated with levetiracetam (50 or 100 mg/kg/day, i.p.) for three days. The colonic tissue samples were dissected for biochemical, RT-PCR and immunofluorescence analysis. Results showed that levetiracetam treatment significantly decreased colonic mucosal injury as evidenced by the macroscopic and histopathological analysis. Levetiracetam induced Nrf2/HO-1 and antioxidants while reduced lipid peroxidation and myeloperoxidase activity in colon tissue. Levetiracetam treatment decreased NF-κB activity and the expression of proinflammatory mediators TNF-α, IL-6, IL-1β, IFN-γ, MCP-1 and ICAM-1. The colonic levels of anti-inflammatory cytokines IL-10 and TGF-β1 were increased by levetiracetam treatment. Furthermore, levetiracetam significantly diminished iNOS expression and NO production in colon tissue. These findings suggest that levetiracetam ameliorates the severity of UC in mice through the regulation of inflammatory and oxidative responses.

Protective effect of luteoloside against Toxoplasma gondii-induced liver injury through inhibiting TLR4/NF-κB and P2X7R/NLRP3 and enhancing Nrf2/HO-1 signaling pathway

Toxoplasma gondii (T. gondii) infection can cause liver injury by inducing inflammation and oxidative stress. The Chinese herbal extract luteoloside (Lut) has considerable anti-inflammatory and antioxidant properties, but its effects on the liver injury during T. gondii infection have not been reported. This study investigated the hepatoprotective effects of Lut by treating T. gondii-infected mice with 0-200 mg/kg doses of Lut and further examined the expression of key proteins in the inflammation and oxidative stress-related pathways in the liver to investigate the potential mechanism of the hepatoprotective effects of Lut. Results showed that Lut remarkably reduced serum ALT and AST levels, considerably decreased inflammatory factors TNF-α, IL-6, and IL-1β, as well as oxidative products MDA, and greatly increased antioxidant enzymes SOD and GSH. The expression of key proteins TLR4, Myd88, TRAF6, p-NF-κB p65 in the TLR4/NF-κB pathway and P2X7R, NLRP3, caspase 1, IL-1β, IL-18 in the P2X7R/NLRP3 pathway were significantly decreased in the liver. And the expression of key proteins Nrf2, HO-1, NQO-1, and GCLC in the Nrf2/HO-1 antioxidant-related pathway was significantly upregulated. In conclusion, Lut attenuated T. gondii-induced liver injury by inhibiting the inflammatory response and enhancing antioxidant capacity. The hepatoprotective mechanisms of Lut are involved in inhibiting TLR4/NF-κB and P2X7R/NLRP3 inflammatory signaling pathways, as well as enhancing the Nrf2/HO-1 antioxidant pathway. These findings not only provide some reference for further exploring the specific hepatoprotective mechanism of Lut during T. gondii infection, but also provide some theoretical basis for the future clinical application of Lut as a hepatoprotective drug in T. gondii infection.

Chlorogenic Acid Attenuates Doxorubicin-Induced Oxidative Stress and Markers of Apoptosis in Cardiomyocytes via Nrf2/HO-1 and Dityrosine Signaling

(1) Background: Doxorubicin (DOX) is extensively used for cancer treatments; however, its clinical application is limited because of its cardiotoxic adverse effects. A combination of DOX and agents with cardioprotective properties is an effective strategy to ameliorate DOX-related cardiotoxicity. Polyphenolic compounds are ideal for the investigation of novel cardioprotective agents. Chlorogenic acid (CGA), an essential dietary polyphenol found in plants, has been previously reported to exert antioxidant, cardioprotective, and antiapoptotic properties. The current research evaluated CGA's in vivo cardioprotective properties in DOX-induced cardiotoxicity and the probable mechanisms underlying this protection. (2) Methods: CGA's cardioprotective properties were investigated in rats that were treated with CGA (100 mg/kg, p.o.) for fourteen days. The experimental model of cardiotoxicity was induced with a single intraperitoneal (15 mg/kg i.p.) injection of DOX on the 10th day. (3) Results: Treatment with CGA significantly improved the DOX-caused altered cardiac damage markers (LDH, CK-MB, and cTn-T), and a marked improvement in cardiac histopathological features accompanied this. DOX downregulated the expression of Nrf2/HO-1 signaling pathways, and the CGA reversed this effect. Consistently, caspase-3, an apoptotic-related marker, and dityrosine expression were suppressed, while Nrf2 and HO-1 expressions were elevated in the cardiac tissues of DOX-treated rats after treatment with the CGA. Furthermore, the recovery was confirmed by the downregulation of 8-OHdG and dityrosine (DT) expressions in immunohistochemical findings. (4) Conclusions: CGA demonstrated a considerable cardioprotective effect against DOX-induced cardiotoxicity. One of the possible mechanisms for these protective properties was the upregulation of the Nrf2/HO-1-dependent pathway and the downregulation of DT, which may ameliorate oxidative stress and cardiomyocyte apoptosis. These findings suggest that CGA may be cardioprotective, particularly in patients receiving DOX-based chemotherapy.

Umbelliferone protects against methylglyoxal-induced HUVECs dysfunction through suppression of apoptosis and oxidative stress

Methylglyoxal (MGO), a cytotoxic metabolite of glycolysis, can cause endothelial cells impairment, which is tightly associated with diabetic vascular complication. Umbelliferone, a derivative of coumarin, participates in various pharmacological activities. This study aimed to determine the effectiveness of umbelliferone in MGO-induced apoptosis and oxidative stress in endothelial cells. In this study, it has been indicated that umbelliferone inhibited MGO-induced human umbilical vein endothelial cells (HUVECs) cytotoxicity, apoptosis, Bax/Bcl-2 protein ratio, the activity of cleaved-caspase-3, and mitochondrial membrane potential loss. Furthermore, we found that umbelliferone inhibited MGO-induced activation of mitogen-activated protein kinases and nuclear factor-κB signaling pathways in HUVECs. In addition, umbelliferone could suppress oxidative stress, as evidenced by decrease of reactive oxygen species and malondialdehyde (MDA) generation, and increase of superoxide dismutase and glutathione peroxidase contents. Moreover, we found that umbelliferone can activate Nrf2/HO-1 signaling. Importantly, silencing of Nrf2 signaling clearly eliminated the anti-oxidative stress of umbelliferone, whereas umbelliferone pretreatment had no effect on Nrf2 overexpressing HUVECs. Altogether, this study suggested that umbelliferone pretreatment has a protective effect on MGO-induced endothelial cell dysfunction through inhibiting apoptosis and oxidative stress.

Metformin ameliorates calcium oxalate crystallization and stone formation by activating the Nrf2/HO-1 signaling pathway: Two birds with one stone

Deposition of calcium oxalate (CaOx) crystals and oxidative stress-induced injury of renal tubular epithelial cell are the primary pathogenic factors of nephrolithiasis. In this study we investigated the beneficial effects of metformin hydrochloride (MH) against nephrolithiasis and explored the underlying molecular mechanism. Our results demonstrated that MH inhibited the formation of CaOx crystals and promoted the transformation of thermodynamically stable CaOx monohydrate (COM) to more unstable CaOx dihydrate (COD). MH treatment effectively ameliorated oxalate-induced oxidative injury and mitochondrial damage in renal tubular cells and reduced CaOx crystal deposition in rat kidneys. MH also attenuated oxidative stress by lowering MDA level and enhancing SOD activity in HK-2 and NRK-52E cells and in a rat model of nephrolithiasis. In both HK-2 and NRK-52E cells, COM exposure significantlylowered the expressions of HO-1 and Nrf2, which was rescued by MH treatment even in the presence of Nrf2 and HO-1 inhibitors. In rats with nephrolithiasis, MH treatment significantly rescued the down-regulation of the mRNA and protein expression of Nrf2 and HO-1 in the kidneys. These results demonstrate that MH can alleviate CaOx crystal deposition and kidney tissue injury in rats with nephrolithiasis by suppressing oxidative stress and activating the Nrf2/HO-1 signaling pathway, suggesting the potential value of MH in the treatment of nephrolithiasis.