Upregulation Of Heme Oxygenase-1 Research Articles

Prostate cancer-selective anticancer action of an oxindole derivative via HO-1-mediated disruption of metabolic reprogramming.

Prostate cancer, the second leading cause of cancer-related mortality in men, exhibits distinct metabolic reprogramming involving zinc and citrate metabolism. This study investigated whether targeting this unique metabolic profile could offer an effective therapeutic approach. A series of novel oxindole derivatives were synthesized and evaluated for their inhibitory effects on transcription factors (TFs) and antiproliferative activity across various cancer cell lines. Among these, compound 3D showed the strongest inhibition of master TFs (HIF-1α, c-Myc, and SP-1) and demonstrated selective antiproliferative activity in prostate cancer cells. In PC-3 and LNCaP cells, compound 3D suppressed aerobic glycolysis by downregulating lactate-modulating genes (LDHA, MCT1/4, and CAIX) and the zinc influx transporter (ZIP1), without affecting the zinc efflux transporter (ZnT4). Notably, 3D selectively increased heme oxygenase-1 (HO-1) levels in prostate cancer cells, as shown by the proteome profiler oncogene array assay and confirmed by Western blotting. This response was reversed by ZnCl2 treatment. The decreases in LDHA, mitochondrial mass (measured by FACS), and cell proliferation induced by compound 3D were blocked by HO-1-IN-1, an HO-1 inhibitor, and ZnCl2. Furthermore, 3D induced a more pronounced reduction in the oxygen consumption rate (OCR) than in the extracellular acidification rate (EACR), indicating a strong effect on oxidative metabolism. 3D exhibited dose-dependent antitumor efficacy in vivo comparable to that of docetaxel. These findings reveal that the oxindole derivative 3D substantially lowers intracellular zinc levels, yielding potent antitumor effects in prostate cancer through HO-1 upregulation, which impairs mitochondrial function more significantly than aerobic glycolysis.

An Azomethine Derivative, 1-(4-nitrophenyl)-N-phenylmethanimine (BCS2) Ameliorated 7,12-dimethylbenz(a)anthracene-induced Mammary Carcinoma through Nrf2-Keap1-HO-1 Pathway.

The aim of this study is the evaluation of an Azomethine derivative, BCS2, for its antioxidant and anti-tumor activities against mammary carcinoma through the Nrf2- Keap1-HO-1 pathway. The global prevalence of breast cancer is rising at an alarming rate. The facilitation of abnormal cell proliferation in mammary carcinoma occurs due to the disruption of signaling pathways that balance pro- and antioxidant status, thereby producing oxidative stress that disrupts genomic stability. Therefore, introducing a potent antioxidant molecule with antitumor activity is of paramount importance for treating breast cancer. Synthesis, characterization, and in-vitro, in-vivo, and in-silico evaluation of an Azomethine derivative, BCS2, for its antioxidant and anti-tumor activities against chemical carcinogen- induced mammary carcinogenesis in Sprague-Dawley rats. An azomethine derivative, 1-(4-nitrophenyl)-N-phenylmethanimine (BCS2), was synthesized and characterized based on its spectral data. The cytotoxic potential was observed on breast cancer cells, MCF-7, MDA-MB-231, and MDA-MB-468. The in vivo chemotherapeutic potential of BCS2 was established on 7,12-dimethylbenz(a)anthracene (DMBA) induced breast cancer in Sprague-Dawley (SD) rats. The effect of BCS2 on kelch-like ECH-associated protein- 1 (Keap1), Nrf2, heme oxygenase-1 (HO-1), mitogen-activated protein kinase (MAPK), and nuclear factor kappa-light-chain-enhancer of activated-B (NF-κB) was evaluated through ELISA and qPCR techniques. Furthermore, the binding potential and stability of BCS2 with Keap-1, HO-1, and MAPK were predicted using in silico molecular docking and dynamics studies. Additionally, drug-likeness properties of BCS2 were evaluated using in silico ADMET tools. BCS2 showed remarkable cytotoxic activity on MCF-7 cells followed by MDA-MB- 231 and MDA-MB-468 cells having an IC50 of 2.368μM, 4.843μM and 6.472μM respectively, without affecting normal breast cells, MCF-10A. In the DMBA-induced animal model, BCS2 showed potent antitumor potential and showed protective action on endogenous-enzymatic and non-enzymatic antioxidants in cancer-bearing animals. Marked improvement in cellular architecture and ultrastructure of breast/tumor tissues excised from experimental animals was noted through histopathological and field emission scanning electron microscopy (FESEM) analyses. Significant upregulation of antioxidant proteins, Keap1 and HO-1, and downregulation of inflammatory proteins, MAPK, and NF-κB was observed after BCS2 treatment. The in silico computational studies predicted the potent binding of BCS2 with the active pockets of Keap1, HO-1, and MAPK proteins that validated the biological findings. The study revealed BCS2's potent antioxidant and antitumor potential against mammary carcinoma through the Nrf2-Keap1-HO-1 signaling pathway.

Mung bean-derived carbon dots suppress ferroptosis of Schwann cells via the Nrf2/HO-1/GPX4 pathway to promote peripheral nerve repair.

Schwann cells (SCs) can potentially transform into the repair-related cell phenotype after injury, which can promote nerve repair. Ferroptosis occurs in the SCs of injured tissues, causing damage to the SCs and exacerbating nerve injury. Targeting ferroptosis in SCs is a promising therapeutic strategy for effective repair; however, research on ferroptosis in the peripheral nervous system remains limited. In this study, we generated and characterized novel distinctive carbon dots, mung bean-derived carbon dots (MB-CDs). Our results demonstrated that MB-CDs have the advantages of low toxicity, good biocompatibility, high stability, the specific effect of ferric ions (Fe3+) on fluorescence, and antioxidant activity. We demonstrated that MB-CDs promoted functional recovery after peripheral nerve injury (PNI), preventing gastrocnemius atrophy. Further research indicated that MB-CDs boosted the repair-related phenotypes of SCs. We used lipopolysaccharide (LPS) to induce an inflammatory model of SCs and co-cultured them with MB-CDs. Then, we examined the effects of MB-CDs by dividing the cells into four groups: the control group (CTRL), MB-CD treatment group (CDs-SCs), LPS treatment group (LPS-SCs), and LPS and MB-CD treatment group (LPS-CDs). RNA sequencing of LPS-CDs and LPS-SCs indicated that LPS-CDs significantly upregulated heme oxygenase-1 (HO-1) expression. Furthermore, western blotting and immunofluorescence techniques demonstrated that MB-CDs suppressed the ferroptosis of SCs via the Nrf2/HO-1/GPX4 signaling pathway after PNI. Overall, this study further uncovered the connection between ferroptosis and the repair-related phenotypes of SCs, filling this gap in the existing knowledge; accordingly, they may be promising agents for treating PNI.

HMOX1-LDHB interaction promotes ferroptosis by inducing mitochondrial dysfunction in foamy macrophages during advanced atherosclerosis.

Advanced atherosclerosis is the pathological basis for acute cardiovascular events, with significant residual risk of recurrent clinical events despite contemporary treatment. The death of foamy macrophages is a main contributor to plaque progression, but the underlying mechanisms remain unclear. Bulk and single-cell RNA sequencing demonstrated that massive iron accumulation in advanced atherosclerosis promoted foamy macrophage ferroptosis, particularly in low expression of triggering receptor expressed on myeloid cells 2 (TREM2low) foamy macrophages. This cluster exhibits metabolic characteristics with low oxidative phosphorylation (OXPHOS), increasing ferroptosis sensitivity. Mechanically, upregulated heme oxygenase 1 (HMOX1)-lactate dehydrogenase B (LDHB) interaction enables Lon peptidase 1 (LONP1) to degrade mitochondrial transcription factor A (TFAM), leading to mitochondrial dysfunction and ferroptosis. Administration of the mitochondria-targeted reactive oxygen species (ROS) scavenger MitoTEMPO (mitochondrial-targeted TEMPO) or LONP1 inhibitor bortezomib restored mitochondrial homeostasis in foamy macrophages and alleviated atherosclerosis. Collectively, our study elucidates the cellular and molecular mechanism of foamy macrophage ferroptosis, offering potential therapeutic strategies for advanced atherosclerosis.

The C-X-C Motif Chemokine Ligand 5, Which Exerts an Antioxidant Role by Inducing HO-1 Expression, Is C-X-C Motif Chemokine Receptor 2-Dependent in Human Prostate Stroma and Cancer Cells.

While the C-X-C motif chemokine ligand 5 (CXCL5) is recognized as an inflammatory mediator and a potent attractant for immune cells, its functions within the human prostate remain unclear. This study explored the expression, functions, and regulatory mechanisms of CXCL5 in prostate stroma and cancer cells. CXCL5 secreted from prostate cancer cells enhanced neutrophil migration. CXCL5 induced cell proliferation and invasion of prostate cancer cells in vitro and tumorigenesis in a xenograft animal model. C-X-C motif chemokine receptor 2 (CXCR2) has been identified on the surface of prostate fibroblasts and cancer cells. The supernatant of LNCaP cells or CXCL5 overexpression enhanced the migration and contraction of prostate myofibroblast WPMY-1 cells; however, pretreatment with SB225002, a CXCR2 inhibitor, can reverse these effects. CXCL5 evinces antioxidant properties by upregulating heme oxygenase-1 (HO-1) to counteract H2O2-induced reactive oxygen species (ROS) in a CXCR2-dependent manner in WPMY-1 and prostate cancer cells. Our findings illustrate that CXCL5, through HO-1, plays a role in antioxidation, and determine that the CXCL5/CXCR2/HO-1 pathway facilitates antioxidative communication between fibroblasts and cancer cells in the prostate. Therefore, targeting the CXCL5/CXCR2 signaling pathway could provide a new strategy for managing oxidative stress within the prostate.

Self-catalyzed nitric oxide nanocomplexes induce ferroptosis for cancer immunotherapy

Ferroptosis, triggered by membrane lipid peroxidation (LPO) and diminished antioxidants, can be induced by intracellular iron (II, Fe2+). However, the role of nitric oxide (NO) in causing Fe2+ overload for ferroptosis remains uncertain. This study reveals that NO can stimulate endogenous Fe2+ release by upregulating heme oxygenase 1 (HMOX1) expression. Here, ferritin heavy chain (FHC) siRNA and hyaluronic acid (HA)-modified Arg-stabilized zinc peroxide (AZOSH), a non-ferrous-based nanoagent, is synthesized to trigger ferroptosis by inducing intracellular Fe2+ overload. AZOSH, a self-catalyzed NO nanocomplex, effectively generates NO through a reaction of self-supplied Arginine (Arg) and hydrogen peroxide (H2O2), which promotes glutathione (GSH) consumption to downregulate glutathione peroxidase 4 (GPX4) expression and produces peroxynitrite (ONOO−) to enhance LPO. Meanwhile, NO promotes endo/lysosomal escape of siRNA by damaging membrane structures. Moreover, AZOSH significantly triggers Fe2+ overload through the synergistic effects of NO-activated HMOX1 expression and FHC siRNA-mediated ferritin sequestration. Additionally, the released Zn2+ from AZOSH induces oxidative stress by inhibiting mitochondrial function, further promoting ferroptosis. Consequently, AZOSH-mediated ferroptosis exhibits a strong cellular immunogenic response for T-cell activation and infiltration. Importantly, the integration of AZOSH with an anti-PD-1 antibody results in notable antitumor efficacy in vivo. Therefore, this study provides a novel concept of NO-induced ferroptosis, highlighting its role in enhancing PD-1-based immunotherapeutic efficacy.

Designing Nano-Hemin for Ferroptosis-Mediated Cell Death via Enzymatic Hemin Digestion.

Hemin is a protoporphyrin complex of ferric ion which catalyzes H2O2 degradation and produces reactive oxygen species (ROS). This ROS generation property induces oxidative stress to hemin-exposed cells that can lead to various situations such as intracellular Fenton reaction, ferroptosis, or autophagy. Therapeutic performance of hemin is hindered due to low bioavailability of the active monomeric form with an intact ROS generation property. Here, we demonstrate a colloidal nanoparticle form of hemin (nano-hemin) with a high ROS generation property and high cell uptake property. We have shown that nano-hemin produces ROS inside a cell that upregulate heme oxygenase-1 in order to metabolize hemin. This leads to the ferroptosis-mediated cell death. Furthermore, we show that the ROS generation property of nano-hemin can be modulated to control hemin cytotoxicity for either ferroptosis or autophagy. Our findings suggest that nano-hemin can be designed with modular cytotoxicity for different therapeutic applications.

Demyelination in cuprizone mice is ameliorated by calycosin mediated through astrocyte Nrf2 signaling pathway

Oxidative stress plays a pivotal role in multiple sclerosis (MS), triggering demyelination predominantly through excessive peroxide production and the depletion of antioxidants. The accumulation of oxidative damage can be caused by dysregulation of astrocytes, which are the brain's main regulators of oxidative homeostasis. Calycosin, an essential bioactive component extracted from Astragalus, is recognized for its neuroprotective properties. Although recent research has highlighted calycosin's neuroprotective capabilities, its role in demyelinating conditions like MS remains unclear. In this work, we examined the possible molecular mechanism of calycosin's neuroprotective effect on cuprizone (CPZ)-induced demylination in mice. According to our research, calycosin successfully reduced demyelination and behavioral dysfuction in CPZ mice. Calycosin also decreased the production of oxidative stress and enhanced the expression of antioxidants in CPZ mice and in astrocytes induced by hydrogen peroxide (H2O2). Furthermore, both in vivo and in vitro experiments demonstrated that calycosin promoted the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) along with the upregulation of heme oxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and superoxide dismutase (SOD). Importantly, the application of all-trans retinoic acid (ATRA), a specific inhibitor of Nrf2, effectively reversed the myelin-protective and antioxidant effects conferred by calycosin. This study suggested that calycosin might exert neuroprotection by inhibiting oxidative stress and reducing demyelination via the activation of astrocyte Nrf2 signaling. These findings indicated that calycosin might be a potential candidate for treating MS.

Roles of mTOR-p70S6K signaling pathway and HO-1 in ethylbenzene-induced hepatoxic effects in L02 cells

Ethylbenzene (EB)-induced hepatotoxic effects has been indicated as oxidative damage and mitochondria-mediated apoptosis in vivo in our previous study, yet the mechanisms remain unclear. This study aimed to explore the role of the mTOR-p70S6K signaling pathway in EB-induced hepatoxic effects in vitro. Normal human hepatocytes (L02 cells) were exposed to different concentrations of ethylbenzene (0–10 mM) for 24 h. In vitro, we found that EB treatment decreased the viability of L02 cells, via inducing oxidative stress, mitochondrial impairments, excessive apoptosis and autophagy. These were accompanied by the inactivation of the mTOR-p70S6K signaling cascade, as manifested by the decreased levels of related molecules Atg family proteins and Heme oxygenase-1 (HO-1). These findings were further confirmed by mTOR inhibitor treatment and immunofluorescence analysis. Jointly, our results indicate that EB induces hepatoxic effects by triggering mitochondrial impairments and excess apoptosis and autophagy in L02 cells via suppressing the mTOR-p70S6K signaling, and oxidative stress affects the passive up-regulation of HO-1.

Eicosapentaenoic acid induces macrophage Mox polarization to prevent diabetic cardiomyopathy

Diabetic cardiomyopathy (DC) leads to heart failure, with few effective approaches for its intervention. Eicosapentaenoic acid (EPA) is an essential nutrient that benefits the cardiovascular system, but its effect on DC remains unknown. Here, we report that EPA protects against DC in streptozotocin and high-fat diet-induced diabetic mice, with an emphasis on the reduction of cardiac M1-polarized macrophages. In vitro, EPA abrogates cardiomyocyte injury induced by M1-polarized macrophages, switching macrophage phenotype from M1 to Mox, but not M2, polarization. Moreover, macrophage Mox polarization combats M1-polarized macrophage-induced cardiomyocyte injury. Further, heme oxygenase 1 (HO-1) was identified to maintain the Mox phenotype, mediating EPA suppression of macrophage M1 polarization and the consequential cardiomyocyte injury. Mechanistic studies reveal that G-protein-coupled receptor 120 mediates the upregulation of HO-1 by EPA. Notably, EPA promotes Mox polarization in monocyte-derived macrophages from diabetic patients. The current study provides EPA and macrophage Mox polarization as novel strategies for DC intervention.

Acupoint Autohemotherapy Alleviates Airway Inflammation in Asthmatic Rats via Upregulating Expression of Hemeoxygenase-1.

Acupoint autohemotherapy (AA), a therapeutic technique involving the subcutaneous injection of autologous blood into acupoints, has been empirically validated as safe and effective for treating asthma by alleviating symptoms and decreasing acute attacks, though its mechanism is not well understood. The role of heme oxygenase-1 (HO-1) in AA-induced suppression of asthmatic airway inflammation is examined. Twenty rats were assigned randomly to four groups, namely the Control, OVA, OVA + AA, and (OVA + Snpp) + AA. Rats in the OVA + AA and (OVA + Snpp) + AA received autologous blood injections into acupoints (BL13 and BL23) following OVA challenge. Rats in the (OVA + Snpp) + AA were concurrently subjected to intraperitoneal injections of Snpp, a inhibitor of HO-1. Airway inflammation was evaluated through HE staining, while the concentrations of cytokines in BALF were quantified using ELISA. The mRNA and protein levels of RORγt (Th17-specific transcription factor), Foxp3 (Treg-specific transcription factor), and HO-1 in lung tissue were assessed through qRT-PCR and WB. HE staining indicated that airway inflammation was alleviated in the OVA + AA. The OVA + AA displayed significantly lower counts of total cells and eosinophils in the BALF compared to both the OVA and (OVA + Snpp) + AA. The ELISA demonstrated a significant decrease in levels of pro-inflamatory cytokines (IL-4, IL-17A), and an increase in levels of anti-inflamatory cytokines (IFN-γ, IL-10), in the OVA + AA when compared to both OVA and (OVA + Snpp) + AA. The qRT-PCR and WB analyses revealed an upregulation of HO-1 and Foxp3 expression, and a downregulation of RORγt expression, in the OVA + AA when compared to OVA and (OVA + Snpp) + AA. The involvement of HO-1 in the underlying mechanism responsible for the anti-inflammatory effects of AA is evident.

Mevastatin-Induced HO-1 Expression in Cardiac Fibroblasts: A Strategy to Combat Cardiovascular Inflammation and Fibrosis.

Mevastatin (MVS) is known for its anti-inflammatory effects, potentially achieved by upregulating heme oxygenase-1 (HO-1), an enzyme involved in cytoprotection against oxidative injury. Nonetheless, the specific processes by which MVS stimulates HO-1 expression in human cardiac fibroblasts (HCFs) are not yet fully understood. In this study, we found that MVS treatment increased HO-1 mRNA and protein levels in HCFs. This induction was inhibited by pretreatment with specific inhibitors of p38 MAPK, JNK1/2, and FoxO1, and by siRNAs targeting NOX2, p47phox, p38, JNK1, FoxO1, Keap1, and Nrf2. MVS also triggered ROS generation and activated JNK1/2 and p38 MAPK, both attenuated by NADPH oxidase or ROS inhibitors. Additionally, MVS promoted the phosphorylation of FoxO1 and Nrf2, which was suppressed by p38 MAPK or JNK1/2 inhibitor. Furthermore, MVS inhibited TNF-α-induced NF-κB activation and vascular cell adhesion molecule-1 (VCAM-1) expression via the HO-1/CO pathway in HCFs. In summary, the induction of HO-1 expression in HCFs by MVS is mediated through two primary signaling pathways: NADPH oxidase/ROS/p38 MAPK, and JNK1/2/FoxO1 and Nrf2. This research illuminates the underlying processes through which MVS exerts its anti-inflammatory effects by modulating HO-1 in cardiac fibroblasts.

Carbon monoxide as a negative feedback mechanism on HIF-1α in the progression of metabolic-associated fatty liver disease

Metabolic-associated fatty liver disease (MAFLD) encompasses various chronic liver conditions, yet lacks approved drugs. Hypoxia-inducible factor-1α (HIF-1α) is pivotal in MAFLD development. Our prior research highlighted the efficacy of the nano-designed carbon monoxide (CO) donor, targeting HIF-1α in a mouse hepatic steatosis model. Given heme oxygenase-1 (HO-1, a major downstream molecule of HIF-1α) as the primary source of intrinsic CO, we hypothesized that upregulation of HO-1/CO, responsive to HIF-1α, forms a negative feedback loop regulating MAFLD progression. In this study, we explored the potential negative feedback mechanism of CO on HIF-1α and its downstream effects on MAFLD advancement. HIF-1α emerges early in hepatic steatosis induced by a high-fat (HF) diet, triggering increased HO-1 and inflammation. SMA/CORM2 effectively suppresses HIF-1α and steatosis progression when administered within the initial week of HF diet initiation but loses impact later. In adipose tissues, concurrent metabolic dysfunction and inflammation with HIF-1α activation suggest adipose tissue expansion initiates HF-induced steatosis, triggering hypoxia and liver inflammation. Notably, in an in vitro study using mouse hepatocytes treated with fatty acids, downregulating HO-1 intensified HIF-1α induction at moderate fatty acid concentrations. However, this effect diminished at high concentrations. These results suggest the HIF-1α–HO–1-CO axis as a feedback loop under physiological and mild pathological conditions. Excessive HIF-1α upregulation in pathological conditions overwhelms the CO feedback loop. Additional CO application effectively suppresses HIF-1α and disease progression, indicating potential application for MAFLD control.

Cancer cell membrane-camouflaged curcumin nanoparticles trigger ferroptosis for accurate gastric cancer therapy

Curcumin (CUR) is a hydrophobic polyphenol with considerable antitumor efficiency, but its clinical application is limited because of its poor solubility and low stability in aqueous solution and lack of targeting in vivo. Herein, we fabricated a tumor-targeting drug delivery system by loading CUR and cloaking homologous cancer cell membrane (CM) onto mesoporous silica NPs (MSN-CUR@CM). Characterization analysis showed that MSN-CUR@CM with a size of approximately 70 nm showed high water solubility and biocompatibility. Besides, MSN-CUR@CM exhibited tumor-targeting and excellent anti-gastric cancer efficiency both in vitro and in vivo owing to the cellular self-recognition of CM. In the established xenograft tumor nude mouse model, it was still significantly drug accumulated at the tumor site 72 h post administration. In addition, the mean tumor volume and weight of the MSN-CUR@CM group were was 3.97 and 7.47 times smaller than those of the CUR group. Ferroptosis, a type of non-apoptotic regulated cell death accompanied by iron-dependent lipid peroxidation, was triggered by MSN-CUR@CM. Further analysis demonstrated that MSN-CUR@CUR upregulated heme oxygenase (HO)-1 levels whereas it downregulated the expression of glutathione peroxidase 4 (GPX4) in SGC7901 cells in vitro, indicating that the canonical and noncanonical ferroptosis pathways were regulated by MSN-CUR@CM. In conclusion, our study demonstrated that MSN-CUR@CM with high water solubility, biocompatibility, and tumor-targeting properties inhibited gastric cancer both in vitro and in vivo by triggering ferroptosis and provided an admirable cancer therapy efficacy.

Sulfiredoxin-1 accelerates erastin-induced ferroptosis in HT-22 hippocampal neurons by driving heme Oxygenase-1 activation

Ferroptosis, a recently identified non-apoptotic form of cell death, is strongly associated with neurological diseases and has emerged as a potential therapeutic target. Nevertheless, the fundamental mechanisms are still predominantly unidentified. In the current investigation, sulfiredoxin-1 (SRXN1) has been identified as a crucial regulator that enhances the susceptibility to ferroptosis in HT-22 mouse hippocampal cells treated with erastin. Utilizing TMT-based proteomics, a significant increase in SRXN1 expression was observed in erastin-exposed HT-22 cells. Efficient amelioration of erastin-induced ferroptosis was achieved via the knockdown of SRXN1, which resulted in the reduction of intracellular Fe2+ levels and reactive oxygen species (ROS) in HT-22 cells. Notably, the activation of Heme Oxygenase-1 (HO-1) was found to be crucial for inducing SRXN1 expression in HT-22 cells upon treatment with erastin. SRXN1 increased intracellular ROS and Fe2+ levels by activating HO-1 expression, which promoted erastin-induced ferroptosis in HT-22 cells. Inhibiting SRXN1 or HO-1 alleviated erastin-induced autophagy in HT-22 cells. Additionally, upregulation of SRXN1 or HO-1 increased the susceptibility of HT-22 cells to ferroptosis, a process that was counteracted by the autophagy inhibitor 3-Methyladenine (3-MA). These results indicate that SRXN1 is a key regulator of ferroptosis, activating the HO-1 protein through cellular redox regulation, ferrous iron accumulation, and autophagy in HT-22 cells. These findings elucidate a novel molecular mechanism of erastin-induced ferroptosis sensitivity and suggest that SRXN1-HO-1-autophagy-dependent ferroptosis serves as a promising treatment approach for neurodegenerative diseases.

The Metabolite of γ-Tocopherol, 2,7,8-Trimethyl-2-(2′-Carboxyethyl)-6-Hydroxychroman, Exerts Intracellular Antioxidant Activity via Up-Regulation of Heme Oxygenase-1 in Hepatocytes

γ-Tocopherol (γT) is the major form of vitamin E contained in plants and seed oils. Although it is readily metabolized in the liver, the function of the metabolites is not fully understood. This study investigated the antioxidant activities of the γT metabolite 2,7,8-trimethyl-2-(2′-carboxyethyl)-6-hydroxychroman (γCEHC) in comparison to its parent compound. The pretreatment of mouse hepatoma Hepa1c1c7 cells with γCEHC showed a cytoprotective effect on the hydrogen peroxide-induced cytotoxicity to a lesser extent than that of γT. A mechanistic investigation revealed that both γ-CEHC and γT significantly up-regulated the gene and protein expressions of heme oxygenase-1 (HO-1) via the promotion of the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). Furthermore, the combination of γCEHC and γT significantly increased the gene and protein levels of HO-1 and the nuclear translocation of Nrf2, suggesting that it was an additive effect. Tin protoporphyrin IX (SnPP), a representative HO-1 inhibitor, significantly impaired the cytoprotection of γCEHC and γT against the hydrogen peroxide-induced cytotoxicity. These results suggested that not only γT but also its metabolite, γCEHC, are a promising cytoprotective factor against oxidative stress-induced cytotoxicity and that the cytoprotective effect is attributable to the cooperation of both compounds.

Abstract Tu132: Estrogen modulation of ethanol-evoked cardiac oxidative stress and dysfunction: Role of circadian clock period-2 and ferroptosis in estrogen deficient rats

Background: Alcohol triggers exacerbated cardiovascular effects in females, compared to males, in estrogen (E2) dependent manner. E2 provides cardiac protection in premenopausal women and models of menopause, yet the interplay between the circadian clock proteins and E2 in the female heart, particularly in the presence of ethanol (EtOH) remains unclear. Aim: This study aims to determine if the suppression of the circadian clock protein Period 2 (Per2) and associated redox enzymes contribute to E2-mediated exacerbation of the EtOH-induced cardiac ferroptosis, and dysfunction. Methods: Two groups of female Sprague-Dawley rats (n=6-8) were subjected to bilateral ovariectomy (OVX) and fed with EtOH (5% in liquid diet) in the presence of E2 or its vehicle for 8 weeks. Measurements of cardiac function using radiotelemetry and echocardiography along with ex vivo biochemical/molecular studies. Results: Compared to vehicle treated OVX+EtOH group, the E2-treated OVX+EtOH group exhibited: (1) reduced (p<0.05) body weight gain and fat mass; (2) higher (p<0.05) telemetry-measured blood pressure and heart rate; (3) reductions (p<0.05) in echocardiography derived contractility indices, ejection fraction and fractional shortening. In the same group, ex vivo molecular analysis demonstrated: (1) lower cardiac Per2 and suppressed (p<0.05) redox enzymes; (2) increased (p<0.05) ROS level and glutathione depletion (p<0.05), leading to the degradation of glutathione peroxidase 4 (GPX4); (3) heme oxygenase-1 upregulation leading to iron overload (p<0.05). These ferroptosis-related effects resulted in increased lipid peroxidation (p<0.05) compared to findings in OVX+EtOH rats in the absence of E2. Conclusion: This study is the first to suggest that abrogation of the E2-mediated Per2 upregulation unraveled cardiac ferroptosis and contributes to the detrimental cardiac effects of ethanol in E2-replete rats. These novel findings underscore the potential risk for myocardial ferroptosis and dysfunction in menopausal women who are consuming ethanol while on E2 replacement therapy.

Gut-derived wild blueberry phenolic acid metabolites modulate extrinsic cutaneous damage.

As the first line of defense, the skin is equipped with various physiological mechanisms positioned to prevent incoming oxidative damage from numerous environmental insults. With persistent exposure to the environment, understanding ways to augment the skin defenses is paramount in protecting from premature aging. In this study, we investigated the ability of five dietary phenolic metabolites, typically found in the bloodstream after wild blueberry consumption, to successfully defend the skin from UV light exposure in a novel ex vivo co-culture model of human skin explants and primary endothelial cells. Skin explants, placed in transwell inserts, were exposed to UV, and subsequently co-cultured with endothelial cells. When the endothelial cells had been pretreated with the bioactive metabolites at physiological concentrations (hippuric acid 3000 nM, isoferulic acid 1000 nM, salicylic acid 130 nM, benzoic acid 900 nM, α-hydroxyhippuric acid 400 nM) cutaneous damage was prevented on the co-cultured with UV-challenged skin explants. Co-culture with non-pretreated endothelial cells did not protect skin explants. Specifically, the pretreatment was able to reduce skin lipid peroxidation (measured as 4-hydroxynonenal protein adducts), and pro-inflammatory enzymes such as cyclooxygenase 2 (COX-2) and NADPH oxidase 4 (NOX-4). Furthermore, pretreatment with the metabolites prevented UV-induced release of inflammatory cytokines such as IL-1β and IL-8 as well as nitric oxides (NO) levels. In addition, the metabolites showed an impressive ability to prevent the loss of cutaneous structural proteins including involucrin and collagen type 1. Of note, endothelial cells cultured with UV exposed skin explants exhibited increased oxidative stress demonstrated by heme oxygenase-1 (HO-1) up-regulation which was significantly prevented in the metabolite treated models. These findings highlight the ability of dietary polyphenolic metabolites to improve cutaneous defenses against extrinsic stressors.

Emodin alleviates intestinal ischemia–reperfusion injury through antioxidant stress, anti-inflammatory responses and anti-apoptosis effects via Akt-mediated HO-1 upregulation

BackgroundIntestinal ischemia–reperfusion (I/R) injury is a severe vascular emergency. Previous research indicated the protective effects of Emodin on I/R injury. Our study aims to explore the effect of Emodin on intestinal I/R (II/R) injury and elucidate the underlying mechanisms.MethodsC57BL/6 mice and Caco-2 cells were used for in vivo and in vitro studies. We established an animal model of II/R injury by temporarily occluding superior mesenteric artery. We constructed an oxygen–glucose deprivation/reoxygenation (OGD/R) cell model using a hypoxia-reoxygenation incubator. Different doses of Emodin were explored to determine the optimal therapeutic dose. Additionally, inhibitors targeting the protein kinase B (Akt) or Heme oxygenase-1 (HO-1) were administered to investigate their potential protective mechanisms.ResultsOur results demonstrated that in animal experiments, Emodin mitigated barrier disruption, minimized inflammation, reduced oxidative stress, and inhibited apoptosis. When Akt or HO-1 was inhibited, the protective effect of Emodin was eliminated. Inhibiting Akt also reduced the level of HO-1. In cell experiments, Emodin reduced inflammation and apoptosis in the OGD/R cell model. Additionally, when Akt or HO-1 was inhibited, the protective effect of Emodin was weakened.ConclusionsOur findings suggest that Emodin may protect the intestine against II/R injury through the Akt/HO-1 signaling pathway.

Mild hypothermia protects against radiation-induced intestinal injury in mice via upregulation of heme oxygenase-1

Radiation can cause life-threatening intestinal damage, whether intentional or unintentional. The present study investigated the effects of mild hypothermia on radiation-induced intestinal injury and survival. For 1 h before and after a lethal dose of whole-body irradiation (13 Gy), mice were either maintained at normothermia (37 °C) or exposed to mild hypothermia (32 °C). The survival of the mice was monitored for 30 days, and the morphological changes in the intestine and the cytokine levels in the serum of the irradiated mice at normothermia or hypothermia were assessed by histological examination at 12 h, 3.5 days, and 5 days after irradiation. Hypothermia delayed the death of the mice and attenuated the damage to the intestine. Hypothermia reduced apoptosis in the jejunum 12 h after irradiation exposure and restored crypt number, villi length, and epithelial length of the jejunum after 3.5 days. Mild hypothermia also reduced serum levels of proinflammatory cytokines after radiation exposure. Furthermore, heme oxygenase-1 (HO-1) was specifically upregulated in the mouse intestine by hypothermia. The HO-1 inhibitor Sn(IV) protoporphyrin IX dichloride partially reversed the effect mild hypothermia had on HO-1. These results suggest that hypothermia is a protective factor against radiation-induced intestinal damage and can, therefore, be effectively used as a radioprotective condition. In summary, mild hypothermia reduced cell death and inflammation in radiation-induced intestinal injury, partly through the regulation of HO-1.