The immune function of heme oxygenase-1 (HO-1) from Nile tilapia (Oreochromis niloticus) in response to bacterial infection.

Heme oxygenase-1 (HO-1), an inducible rate-limiting metabolic enzyme, exerts critical immunomodulatory functions by potential anti-oxidant, anti-inflammatory, and anti-apoptotic activities. Although accumulative studies have focused on the immune functions of HO-1 in mammals, the roles in fish are poorly understood, and the reports on involvement in the defensive and immune response are very limited. In this study, On-HO-1 gene from Oreochromis niloticus was successfully cloned and identified, which contained an open reading frame (ORF) of 816 bp and coded for a protein of 271 amino acids. The On-HO-1 protein phylogenetically shared a high homology with HO-1 in other teleost fish (76.10%-98.89 %) and a lowly homology with HO-1 in mammals (38.98%-41.55 %). The expression levels of On-HO-1 were highest in the liver of healthy tilapias and sharply induced by Streptococcus agalactiae or Aeromonas hydrophila. Besides, On-HO-1 overexpression significantly increased non-specific immunological parameters in serum during bacterial infection, including LZM, SOD, CAT, ACP, and AKP. It also exerted anti-inflammatory and anti-apoptotic effects in response to the immune response of the infection with S. agalactiae or A. hydrophila by upregulating anti-inflammatory factors (IL-10, TGF-ß), autophagy factors (ATG6, ATG8) and immune-related pathway factors (P65, P38), and down-regulating pro-inflammatory factors (IL-1ß, IL-6, TNF-α), apoptotic factors (Caspase3, Caspase9), pyroptosis factor (Caspase1), and inflammasome (NLRP3). These results suggested that On-HO-1 involved in immunomodulatory functions and host defense in Nile tilapia.

Effects of Cycloastragenol on Alzheimer's Disease in Rats by Reducing Oxidative Stress, Inflammation, and Apoptosis.

BACKGROUND: As individuals age, they may develop Alzheimer's disease (AD), which is characterized by difficulties in speech, memory loss, and other issues related to neural function. Cycloastragenol is an active ingredient of Astragalus trojanus and has been used to treat inflammation, aging, heart disease, and cancer. OBJECTIVES: This study aimed to explore the potential therapeutic benefits of cycloastragenol in rats with experimentally induced AD. Moreover, the underlying molecular mechanisms were also evaluated by measuring Nrf2 and HO-1, which are involved in oxidative stress, NFκB and TNF-α, which are involved in inflammation, and BCL2, BAX, and caspase-3, which are involved in apoptosis. METHODS: Sprague-Dawley rats were given 70 mg/kg of aluminum chloride intraperitoneally daily for six weeks to induce AD. Following AD induction, the rats were given 25 mg/kg of cycloastragenol daily by oral gavage for three weeks. Hippocampal sections were stained with hematoxylin/ eosin and with anti-caspase-3 antibodies. The Nrf2, HO-1, NFκB, TNF-α, BCL2, BAX, and caspase-3 gene expressions and protein levels in the samples were analyzed. RESULTS: Cycloastragenol significantly improved rats' behavioral test performance. It also strengthened the organization of the hippocampus. Cycloastragenol significantly improved behavioral performance and improved hippocampal structure in rats. It caused a marked decrease in the expression of NFκB, TNF-α, BAX, and caspase-3, which was associated with an increase in the expression of BCL2, Nrf2, and HO-1. CONCLUSION: Cycloastragenol improved the structure of the hippocampus in rats with AD. It enhanced the outcomes of behavioral tests, decreased the concentration of AChE in the brain, and exerted antioxidant and anti-inflammatory effects. Antiapoptotic effects were also noted, leading to significant improvements in cognitive function, memory, and behavior in treated rats.

Pyrogallol protects against influenza A virus-triggered lethal lung injury by activating the Nrf2-PPAR-γ-HO-1 signaling axis.

Pyrogallol, a natural polyphenol compound (1,2,3-trihydroxybenzene), has shown efficacy in the therapeutic treatment of disorders associated with inflammation. Nevertheless, the mechanisms underlying the protective properties of pyrogallol against influenza A virus infection are not yet established. We established in this study that pyrogallol effectively alleviated H1N1 influenza A virus-induced lung injury and reduced mortality. Treatment with pyrogallol was found to promote the expression and nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) and peroxisome proliferator-activated receptor gamma (PPAR-γ). Notably, the activation of Nrf2 by pyrogallol was involved in elevating the expression of PPAR-γ, both of which act synergistically to enhance heme oxygenase-1 (HO-1) synthesis. Blocking HO-1 by zinc protoporphyrin (ZnPP) reduced the suppressive impact of pyrogallol on H1N1 virus-mediated aberrant retinoic acid-inducible gene-I-nuclear factor kappa B (RIG-I-NF-κB) signaling, which thus abolished the dampening effects of pyrogallol on excessive proinflammatory mediators and cell death (including apoptosis, necrosis, and ferroptosis). Furthermore, the HO-1-independent inactivation of janus kinase 1/signal transducers and activators of transcription (JAK1/STATs) and the HO-1-dependent RIG-I-augmented STAT1/2 activation were both abrogated by pyrogallol, resulting in suppression of the enhanced transcriptional activity of interferon-stimulated gene factor 3 (ISGF3) complexes, thus prominently inhibiting the amplification of the H1N1 virus-induced proinflammatory reaction and apoptosis in interferon-beta (IFN-ß)-sensitized cells. The study provides evidence that pyrogallol alleviates excessive proinflammatory responses and abnormal cell death via HO-1 induction, suggesting it could be a potential agent for treating influenza.

Taurine Chloramine-Mediated Nrf2 Activation and HO-1 Induction Confer Protective Effects in Astrocytes.

Taurine is ubiquitously distributed in mammalian tissues, with the highest levels in the brain, heart, and leukocytes. Taurine reacts with hypochlorous acid (HOCl) to produce taurine chloramine (Tau-Cl) via the myeloperoxidase (MPO) system. In this study, we elucidated the antioxidative and protective effects of Tau-Cl in astrocytes. Tau-Cl increased the expression and nuclear translocation of nuclear factor E2-related factor (Nrf2) and the expression of Nrf2-regulated antioxidant genes, including heme oxygenase 1 (HO-1). Nrf2 activity is negatively regulated by Kelch-like ECH-associated protein 1 (Keap1). Tau-Cl decreased the level of the reduced thiol groups of Keap1, resulting in the disruption of the Keap1-Nrf2 complex. Consequently, Tau-Cl rescued the H2O2-induced cell death by enhancing HO-1 expression and suppressing reactive oxygen species. In conclusion, Tau-Cl confers protective effects in astrocytes by disrupting the Keap1-Nrf2 complex, thereby promoting Nrf2 translocation to the nucleus, wherein it binds to the antioxidant response element (ARE) and accelerates the transcription of antioxidant genes. Therefore, in astrocytes, the activation of the Keap1-Nrf2-ARE pathway by Tau-Cl may increase antioxidants and anti-inflammatory mediators as well as other cytoprotective proteins, conferring protection against brain infection and injury.

Age-Dependent Changes in Nrf2/Keap1 and Target Antioxidant Protein Expression Correlate to Lipoxidative Adducts, and Are Modulated by Dietary N-3 LCPUFA in the Hippocampus of Mice.

The brain has a high metabolism rate that may generate reactive oxygen and nitrogen species. Consequently, nerve cells require highly efficient antioxidant defenses in order to prevent a condition of deleterious oxidative stress. This is particularly relevant in the hippocampus, a highly complex cerebral area involved in processing superior cognitive functions. Most current evidence points to hippocampal oxidative damage as a causal effect for neurodegenerative disorders, especially Alzheimer's disease. Nuclear factor erythroid-2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) is a master key for the transcriptional regulation of antioxidant and detoxifying systems. It is ubiquitously expressed in brain areas, mainly supporting glial cells. In the present study, we have analyzed the relationships between Nrf2 and Keap1 isoforms in hippocampal tissue in response to aging and dietary long-chain polyunsaturated fatty acids (LCPUFA) supplementation. The possible involvement of lipoxidative and nitrosative by-products in the dynamics of the Nrf2/Keap1 complex was examined though determination of protein adducts, namely malondialdehyde (MDA), 4-hydroxynonenal (HNE), and 3-nitro-tyrosine (NTyr) under basal conditions. The results were correlated to the expression of target proteins heme-oxygenase-1 (HO-1) and glutathione peroxidase 4 (GPx4), whose expressions are known to be regulated by Nrf2/Keap1 signaling activation. All variables in this study were obtained simultaneously from the same preparations, allowing multivariate approaches. The results demonstrate a complex modification of the protein expression patterns together with the formation of adducts in response to aging and diet supplementation. Both parameters exhibited a strong interaction. Noticeably, LCPUFA supplementation to aged animals restored the Nrf2/Keap1/target protein patterns to the status observed in young animals, therefore driving a "rejuvenation" of hippocampal antioxidant defense.

Therapeutic effects of genistein in experimentally induced ulcerative colitis in rats via affecting mitochondrial biogenesis.

Ulcerative colitis (UC) is an inflammatory bowel disease that affects the mucosa of the colon, resulting in severe inflammation and ulcers. Genistein is a polyphenolic isoflavone present in several vegetables, such as soybeans and fava beans. Therefore, we conducted the following study to determine the therapeutic effects of genistein on UC in rats by influencing antioxidant activity and mitochondrial biogenesis and the subsequent effects on the apoptotic pathway. UC was induced in rats by single intracolonic administration of 2 ml of 4% acetic acid. Then, UC rats were treated with 25-mg/kg genistein. Colon samples were obtained to assess the gene and protein expression of nuclear factor erythroid 2-related factor-2 (Nrf2), heme oxygenase-1 (HO-1), peroxisome proliferator-activated receptor-gamma coactivator (PGC-1), mitochondrial transcription factor A (TFAM), B-cell lymphoma 2 (BCL2), BCL2-associated X (BAX), caspase-3, caspase-8, and caspase-9. In addition, colon sections were stained with hematoxylin/eosin to investigate the cell structure. The microimages of UC rats revealed inflammatory cell infiltration, hemorrhage, and the destruction of intestinal glands, and these effects were improved by treatment with genistein. Finally, treatment with genistein significantly increased the expression of PGC-1, TFAM, Nrf2, HO-1, and BCL2 and reduced the expression of BAX, caspase-3, caspase-8, and caspase-9. In conclusion, genistein exerted therapeutic effects against UC in rats. This therapeutic activity involved enhancing antioxidant activity and increasing mitochondrial biogenesis, which reduced cell apoptosis.

Activation of Nrf2/HO-1/NQO1 Signaling Pathway by Shenqi Tangluo Pill Improves Oxidative Stress Injury of Skeletal Muscle of Type 2 Diabetes Mellitus Mice / 中国实验方剂学杂志

ObjectiveTo investigate the effect and mechanism of Shenqi Tangluo pill （SQTLP） on oxidative stress injury of skeletal muscle of type 2 diabetes mellitus （T2DM） mice based on nuclear factor erythroid 2-related factor 2 （Nrf2）/heme oxygenase-1 （HO-1）/NAD（P）H quinone oxidoreductase 1 （NQO1） pathway. MethodA total of 60 7-week-old male db/db mice ［specific pathogen-free （SPF） grade］ were selected and fed for one week for adaption. They were divided into the model control group， SQTLP low-， medium- and high-dose （19， 38， and 76 g·kg-1） groups and metformin group （0.26 g·kg-1） by gavage. Each group consisted of 12 mice. Twelve male db/m mice of the same age were selected as the blank group. The intervention was implemented continuously for 8 weeks. Fasting blood glucose （FBG） was detected. Fasting serum insulin （FINS） levels were detected by enzyme-linked immunosorbent assay （ELISA）， and the homeostasis model assessment-insulin resistance （HOMA-IR） index and the homeostasis model assessment-insulin sensitivity index （HOMA-ISI） were calculated. Oral glucose tolerance test （OGTT） and insulin tolerance test （ITT） were conducted. The activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） and the contents of malondialdehyde （MDA） and reduced nicotinamide adenine dinucleotide phosphate （NADPH） in skeletal muscle tissues were detected by biochemical kits. Hematoxylin-eosin （HE） staining was used to observe the pathological changes in skeletal muscle tissues. The levels of reactive oxygen species （ROS） and 4-hydroxynonenal （4-HNE） in skeletal muscle tissue were detected by immunofluorescence （IF）. The expression levels of Nrf2， HO-1， NQO1 and glutamate-cysteine ligase catalytic subunit （GCLC） proteins in skeletal muscle tissues were detected by Western blot. ResultCompared with those in the blank group， FBG， FINS and HOMA-IR in the model group were significantly increased （P<0.05）， while HOMA-ISI was decreased （P<0.05）. The results of OGTT and ITT showed that blood glucose was significantly increased at all time points （P<0.05）， and glucose tolerance and insulin tolerance were significantly impaired. SOD and GSH-Px activities in skeletal muscle tissues were significantly decreased （P<0.05）， and MDA and NADPH contents were significantly increased （P<0.05）. In skeletal muscle tissues， the arrangement of muscle fibers was loose， the nucleus was disordered， and inflammatory cells were infiltrated. The expression levels of ROS and 4-HNE in skeletal muscle tissues were significantly increased （P<0.05）. The protein expression levels of Nrf2， HO-1， NQO1 and GCLC in skeletal muscle tissues were significantly decreased （P<0.05）. Compared with those in the model group， FBG， FINS and HOMA-IR in the metformin group were significantly decreased （P<0.05）， while HOMA-ISI was increased （P<0.05）. The results of OGTT and ITT showed that blood glucose in the metformin group was significantly decreased at all time points （P<0.05）. The activities of SOD and GSH-Px in skeletal muscle tissues were significantly increased （P<0.05）， while the contents of MDA and NADPH were significantly decreased （P<0.05）. No obvious abnormality was found in the skeletal muscle tissue of the metformin group. The expressions of ROS and 4-HNE in skeletal muscle tissues were decreased （P<0.05）. The protein expression levels of Nrf2， HO-1， NQO1 and GCLC in skeletal muscle tissues were significantly increased （P<0.05）. Compared with those in the model group， FBG， FINS and HOMA-IR in the SQTLP medium- and high-dose groups were significantly decreased （P<0.05）， while HOMA-ISI was increased （P<0.05）. The results of OGTT and ITT showed that the glucose tolerance and insulin tolerance of mice were improved in each dose group of SQTLP. The GSH-Px activity in the SQTLP low-dose group was significantly increased （P<0.05）， and the NADPH content was decreased （P<0.05）. The activities of SOD and GSH-Px in the SQTLP medium- and high-dose groups were significantly increased （P<0.05）， while the contents of MDA and NADPH were significantly decreased （P<0.05）. The skeletal muscle tissue injury of mice in each dose group of SQTLP was ameliorated to different degrees. In the SQTLP medium- and high-dose groups， the expressions of ROS and 4-HNE were decreased （P<0.05）， and the protein expression levels of Nrf2， HO-1， NQO1 and GCLC were significantly increased （P<0.05）. Compared with those in the SQTLP low-dose group， FBG and HOMA-IR in the SQTLP high-dose group were significantly decreased （P<0.05）， while HOMA-ISI was increased （P<0.05）. The results of OGTT and ITT showed that the SQTLP high-dose group significantly improved the glucose tolerance and insulin tolerance of mice. The activities of SOD and GSH-Px in skeletal muscle tissues were significantly increased （P<0.05）， while the contents of MDA and NADPH were significantly decreased （P<0.05）. No obvious abnormality was found in the skeletal muscle tissue， the expressions of ROS and 4-HNE were decreased （P<0.05）， and the protein expression levels of Nrf2， HO-1， NQO1 and GCLC were significantly increased （P<0.05） in the skeletal muscle tissue of the SQTLP high-dose group. ConclusionSQTLP can significantly improve IR in T2DM mice， and the mechanism is related to SQTLP activating the Nrf2/HO-1/NQO1 signaling pathway， promoting the expression of antioxidant enzymes， and thus improving the oxidative stress injury in the skeletal muscle.

Guggulsterone protects against lipopolysaccharide-induced inflammation and lethal endotoxemia via heme oxygenase-1.

Guggulsterone (GS) is a phytosterol used to treat inflammatory diseases. Although many studies have examined the anti-inflammatory activities of GS, the detailed mechanisms of GS in lipopolysaccharide (LPS)-induced inflammation and endotoxemia have not yet been examined. Therefore, we investigated the anti-inflammatory effects of GS on LPS-induced inflammation. In murine peritoneal macrophages, the anti-inflammatory activity of GS was primarily mediated by heme oxygenase-1 (HO-1) induction. HO-1 induction by GS was mediated by GSH depletion and reactive oxygen species (ROS) production. The ROS generated by GS caused the phosphorylation of GSK3ß (ser9/21) and p38, leading to the translocation of nuclear factor erythroid-related factor 2 (Nrf2), which ultimately induced HO-1. In addition, GS pretreatment significantly inhibited inducible nitric oxide synthase (iNOS), iNOS-derived NO, and COX-2 protein and mRNA expression, and production of COX-derived prostaglandin PGE2, interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α). In a mouse model of endotoxemia, GS treatment prolonged survival and inhibited the expression of inflammatory mediators, including IL-1ß, IL-6, and TNF-α. GS treatment also inhibited LPS-induced liver injury. These results suggest that GS-induced HO-1 could exert anti-inflammatory effects via ROS-dependent GSK (ser21/9)-p38 phosphorylation and nuclear translocation of Nrf2.

Verbascoside Elicits Its Beneficial Effects by Enhancing Mitochondrial Spare Respiratory Capacity and the Nrf2/HO-1 Mediated Antioxidant System in a Murine Skeletal Muscle Cell Line.

Muscle weakness and muscle loss characterize many physio-pathological conditions, including sarcopenia and many forms of muscular dystrophy, which are often also associated with mitochondrial dysfunction. Verbascoside, a phenylethanoid glycoside of plant origin, also named acteoside, has shown strong antioxidant and anti-fatigue activity in different animal models, but the molecular mechanisms underlying these effects are not completely understood. This study aimed to investigate the influence of verbascoside on mitochondrial function and its protective role against H2O2-induced oxidative damage in murine C2C12 myoblasts and myotubes pre-treated with verbascoside for 24 h and exposed to H2O2. We examined the effects of verbascoside on cell viability, intracellular reactive oxygen species (ROS) production and mitochondrial function through high-resolution respirometry. Moreover, we verified whether verbascoside was able to stimulate nuclear factor erythroid 2-related factor (Nrf2) activity through Western blotting and confocal fluorescence microscopy, and to modulate the transcription of its target genes, such as heme oxygenase-1 (HO-1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), by Real Time PCR. We found that verbascoside (1) improved mitochondrial function by increasing mitochondrial spare respiratory capacity; (2) mitigated the decrease in cell viability induced by H2O2 and reduced ROS levels; (3) promoted the phosphorylation of Nrf2 and its nuclear translocation; (4) increased the transcription levels of HO-1 and, in myoblasts but not in myotubes, those of PGC-1α. These findings contribute to explaining verbascoside's ability to relieve muscular fatigue and could have positive repercussions for the development of therapies aimed at counteracting muscle weakness and mitochondrial dysfunction.

Serum High-Mobility Group Box 1 and Heme Oxygenase-1 as Biomarkers in COVID-19 Patients at Hospital Admission.

The careful monitoring of patients with mild/moderate COVID-19 is of particular importance because of the rapid progression of complications associated with COVID-19. For prognostic reasons and for the economic management of health care resources, additional biomarkers need to be identified, and their monitoring can conceivably be performed in the early stages of the disease. In this retrospective cross-sectional study, we found that serum concentrations of high-mobility group box 1 (HMGB1) and heme oxygenase-1 (HO-1), at the time of hospital admission, could be useful biomarkers for COVID-19 management. The study included 160 randomly selected recovered patients with mild to moderate COVID-19 on admission. Compared with healthy controls, serum HMGB1 and HO-1 levels increased by 487.6 pg/mL versus 43.1 pg/mL and 1497.7 pg/mL versus 756.1 pg/mL, respectively. Serum HO-1 correlated significantly with serum HMGB1, oxidative stress parameters (malondialdehyde (MDA), the phosphatidylcholine/lysophosphatidylcholine ratio (PC/LPC), the ratio of reduced and oxidative glutathione (GSH/GSSG)), and anti-inflammatory acute phase proteins (ferritin, haptoglobin). Increased heme catabolism/hemolysis were not detected. We hypothesize that the increase in HO-1 in the early phase of COVID-19 disease is likely to have a survival benefit by providing protection against oxidative stress and inflammation, whereas the level of HMGB1 increase reflects the activity of the innate immune system and represents levels within which the disease can be kept under control.

Tetramethylpyrazine ameliorates endotoxin-induced acute lung injury by relieving Golgi stress via the Nrf2/HO-1 signaling pathway.

PURPOSE: Endotoxin-induced acute lung injury (ALI) is a severe disease caused by an imbalanced host response to infection. It is necessary to explore novel mechanisms for the treatment of endotoxin-induced ALI. In endotoxin-induced ALI, tetramethylpyrazine (TMP) provides protection through anti-inflammatory, anti-apoptosis, and anti-pyroptosis effects. However, the mechanism of action of TMP in endotoxin-induced ALI remains unclear. Here, we aimed to determine whether TMP can protect the lungs by inhibiting Golgi stress via the Nrf2/HO-1 pathway. METHODS AND RESULTS: Using lipopolysaccharide (LPS)-stimulated C57BL/6J mice and MLE12 alveolar epithelial cells, we observed that TMP pretreatment attenuated endotoxin-induced ALI. LPS + TMP group showed lesser lung pathological damage and a lower rate of apoptotic lung cells than LPS group. Moreover, LPS + TMP group also showed decreased levels of inflammatory factors and oxidative stress damage than LPS group (P < 0.05). Additionally, LPS + TMP group presented reduced Golgi stress by increasing the Golgi matrix protein 130 (GM130), Golgi apparatus Ca2+/Mn2+ ATPases (ATP2C1), and Golgin97 expression while decreasing the Golgi phosphoprotein 3 (GOLPH3) expression than LPS group (P < 0.05). Furthermore, TMP pretreatment promoted Nrf2 and HO-1 expression (P < 0.05). Nrf2-knockout mice or Nrf2 siRNA-transfected MLE12 cells were pretreated with TMP to explore how the Nrf2/HO-1 pathway affected TMP-mediated Golgi stress in endotoxin-induced ALI models. We observed that Nrf2 gene silencing partially reversed the alleviating effect of Golgi stress and the pulmonary protective effect of TMP. CONCLUSION: Our findings showed that TMP therapy reduced endotoxin-induced ALI by suppressing Golgi stress via the Nrf2/HO-1 signaling pathway in vivo and in vitro.

Antitumor Activity of Ferulic Acid Against Ehrlich Solid Carcinoma in Rats via Affecting Hypoxia, Oxidative Stress and Cell Proliferation.

Background Ferulic acid is a natural compound commonly found in fruits and vegetables like tomatoes, sweet corn, rice bran, and dong quai. It has various beneficial effects on the body, such as anti-inflammatory, anti-apoptotic, hepatoprotective, cardioprotective, and neuroprotective properties. Aims We conducted a study to investigate the antitumor activity of ferulic acid against Ehrlich solid carcinoma (ESC), specifically by affecting hypoxia-inducible factor (HIF)-1α and its subsequent effects on other factors like nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), cellular Myc (cMyc), cyclin D1, mammalian target of rapamycin (mTOR), and signal transducer and activator of transcription 3 (STAT3). Materials and methods The study involved implanting rats with ESC cells and administering 50 mg/kg of ferulic acid orally daily for eight days. Sections of the muscles with ESC were stained with toluidine blue or immunostained with anti-HIF-1α antibodies. The tumor samples were used to evaluate the expression of HIF-1α, Nrf2, HO-1, cMyc, cyclin D1, mTOR, and STAT3. Results Ferulic acid increased mean survival time, reduced tumor volume and weight, and improved the appearance of the tumor tissue. Furthermore, ferulic acid significantly elevated the expression of Nrf2 and HO-1, while reducing the expression of HIF-1α, Nrf2, HO-1, cMyc, cyclin D1, mTOR, and STAT3. Conclusions Ferulic acid can reduce tumor size and weight while improving the structure of muscle cells, suggesting it may have antineoplastic activity against ESC. Further investigation revealed that ferulic acid downregulates HIF-1α, increasing the expression of antioxidant proteins Nrf2 and HO-1. Additionally, ferulic acid decreases the expression of proliferation markers cMyc and cyclin D1 and downregulates cellular regulators mTOR and STAT3.

Cytoprotective Role of Heme Oxygenase-1 in Cancer Chemoresistance: Focus on Antioxidant, Antiapoptotic, and Pro-Autophagy Properties.

Chemoresistance remains the foremost challenge in cancer therapy. Targeting reactive oxygen species (ROS) manipulation is a promising strategy in cancer treatment since tumor cells present high levels of intracellular ROS, which makes them more vulnerable to further ROS elevation than normal cells. Nevertheless, dynamic redox evolution and adaptation of tumor cells are capable of counteracting therapy-induced oxidative stress, which leads to chemoresistance. Hence, exploring the cytoprotective mechanisms of tumor cells is urgently needed to overcome chemoresistance. Heme oxygenase-1 (HO-1), a rate-limiting enzyme of heme degradation, acts as a crucial antioxidant defense and cytoprotective molecule in response to cellular stress. Recently, emerging evidence indicated that ROS detoxification and oxidative stress tolerance owing to the antioxidant function of HO-1 contribute to chemoresistance in various cancers. Enhanced HO-1 expression or enzymatic activity was revealed to promote apoptosis resistance and activate protective autophagy, which also involved in the development of chemoresistance. Moreover, inhibition of HO-1 in multiple cancers was identified to reversing chemoresistance or improving chemosensitivity. Here, we summarize the most recent advances regarding the antioxidant, antiapoptotic, and pro-autophagy properties of HO-1 in mediating chemoresistance, highlighting HO-1 as a novel target for overcoming chemoresistance and improving the prognosis of cancer patients.

Nymphoides peltata Root Extracts Improve Atopic Dermatitis by Regulating Skin Inflammatory and Anti-Oxidative Enzymes in 2,4-Dinitrochlorobenzene (DNCB)-Induced SKH-1 Hairless Mice.

Nymphoides peltata is widely used pharmacologically in Traditional Chinese Medicine and Ayurvedic medicine as a diuretic, antipyretic, or choleretic and to treat ulcers, snakebites, and edema. Previous studies have shown that phytochemicals from N. peltata have physiological activities such as anti-inflammatory, anti-tumor, and anti-wrinkle properties. Nevertheless, research on the anti-atopic dermatitis (AD) effect of N. peltata extract is limited. This study was undertaken to assess the in vitro and in vivo anti-atopic and antioxidant activities of a 95% EtOH extract of N. peltata roots (NPR). PI-induced RBL-2H3 cells and two typical hapten mice (oxazolone-induced BALB/c mice and 2,4-dinitrochlorobenzene (DNCB)-induced SKH-1 hairless mice) were used to investigate the effect of NPR extract on AD. The expressions of AD-related inflammatory cytokines, skin-related genes, and antioxidant enzymes were analyzed by ELISA, immunoblotting, and immunofluorescence, and skin hydration was measured using Aquaflux AF103 and SKIN-O-MAT instruments. The chemical composition of NPR extract was analyzed using an HPLC-PDA system. In this study, NPR extracts were shown to most efficiently inhibit IL-4 in PI-induced RBL-2H3 cells and AD-like skin symptoms in oxazolone-BALB/c mice compared to its whole and aerial extracts. NPR extract markedly reduced DNCB-induced increases in mast cells, epidermal thickness, IL-4 and IgE expressions, and atopic-like symptoms in SKH-1 hairless mice. In addition, NPR extract suppressed DNCB-induced changes in the expressions of skin-related genes and skin hydration and activated the Nrf2/HO-1 pathway. Three phenolic acids (chlorogenic acid, 3,5-dicaffeoylquinic acid, and 3,4-dicaffeoylquinic acid) were identified by HPLC-PDA in NPR extract. The study shows that NPR extract exhibits anti-atopic activities by inhibiting inflammatory and oxidative stress and improving skin barrier functions, and indicates that NPR extract has potential therapeutic use for the prevention and treatment of AD.

Human Heme Oxygenase-1 Promoter Activity Is Mediated by Z-DNA Formation.

In recent years, it has been shown that Z-DNA formation in DNA plays functionally significant roles in nucleic acid metabolism, such as gene expression, chromosome recombination, and epigenetic regulation. The reason for the identification of these effects is mainly due to the advancement of Z-DNA detection methods in target genome regions in living cells.The heme oxygenase-1 (HO-1) gene encodes an enzyme that degrades an essential prosthetic heme, and environmental stimuli, including oxidative stress, lead to robust induction of the HO-1 gene. Many DNA elements and transcription factors are involved in the induction of the HO-1 gene, and Z-DNA formation in the thymine-guanine (TG) repetitive sequence in the human HO-1 gene promoter region is required for maximum gene induction.Here, we describe a detailed protocol for Z-DNA detection in the human HO-1 gene promoter region based on chromatin immunoprecipitation with quantitative PCR. We also provide some control experiments to consider in routine lab procedures.

Sex differences in hearing impairment due to diet-induced obesity in CBA/Ca mice.

BACKGROUND: Obesity is an independent risk factor for hearing loss. Although attention has focused on major obesity comorbidities such as cardiovascular disease, stroke, and type 2 diabetes, the impact of obesity on sensorineural organs, including the auditory system, is unclear. Using a high-fat diet (HFD)-induced obese mouse model, we investigated the impact of diet-induced obesity on sexual dimorphism in metabolic alterations and hearing sensitivity. METHODS: Male and female CBA/Ca mice were randomly assigned to three diet groups and fed, from weaning (at 28 days) to 14 weeks of age, a sucrose-matched control diet (10 kcal% fat content diet), or one of two HFDs (45 or 60 kcal% fat content diets). Auditory sensitivity was evaluated based on the auditory brainstem response (ABR), distortion product otoacoustic emission (DPOAE), and ABR wave 1 amplitude at 14 weeks of age, followed by biochemical analyses. RESULTS: We found significant sexual dimorphism in HFD-induced metabolic alterations and obesity-related hearing loss. Male mice exhibited greater weight gain, hyperglycemia, increased ABR thresholds at low frequencies, elevated DPOAE, and lower ABR wave 1 amplitude compared to female mice. The hair cell (HC) ribbon synapse (CtBP2) puncta showed significant sex differences. The serum concentration of adiponectin, an otoprotective adipokine, was significantly higher in female than in male mice; cochlear adiponectin levels were elevated by HFD in female but not male mice. Adiponectin receptor 1 (AdipoR1) was widely expressed in the inner ear, and cochlear AdipoR1 protein levels were increased by HFD, in female but not male mice. Stress granules (G3BP1) were significantly induced by the HFD in both sexes; conversely, inflammatory (IL-1ß) responses were observed only in the male liver and cochlea, consistent with phenotype HFD-induced obesity. CONCLUSIONS: Female mice are more resistant to the negative effects of an HFD on body weight, metabolism, and hearing. Females showed increased peripheral and intra-cochlear adiponectin and AdipoR1 levels, and HC ribbon synapses. These changes may mediate resistance to HFD-induced hearing loss seen in female mice.

Carnosol attenuates high glucose damage in human retinal endothelial cells through regulation of ERK/Nrf2/HO-1 pathway.

Carnosol is a natural compound with antioxidant properties. Based on this evidence, in the present study we investigated whether this compound can protect retinal vascular endothelium from hyperglycemic insult responsible for diabetic retinopathy development. We performed in vitro study on human retinal endothelial cells (HREC) cultured both in normal and high glucose conditions to assess the effects of carnosol on cell viability, Nrf2 expression, HO-1 activity, and ERK1/2 expression. HREC exposed to high glucose insult were treated with carnosol. Data indicated that carnosol treatment is able to induce HO-1 expression via Nrf2 activation and counteracts the damage elicited by high glucose. Further, carnosol activation of Nrf2/HO-1 signaling axis involves ERK1/2 pathway. These data confirm the therapeutic value of carnosol by suggesting its use to treat diabetic retinopathy.

Correlation between serum nesfatin-1, apelin and HO-1 levels and the severity of diabetic retinopathy / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To analyze the correlation between serum nesfatin-1, apelin and heme oxygenase-1(HO-1)levels and the severity of diabetic retinopathy(DR).METHODS:Totally 100 patients with type 2 diabetes mellitus(T2DM)who were admitted to the hospital from September 2020 to September 2022 were selected. They were divided into non-DR(NDR)group(35 cases), nonproliferative DR(NPDR)group(33 cases)and proliferative DR(PDR)group(32 cases)according to the condition of fundus lesions. Another 30 healthy individuals who received health check-ups in the hospital during the same period were selected as the control group. Serum nesfatin-1, apelin and HO-1 levels in each group were detected, and panretinal ischemia index(ISI)was evaluated.RESULTS:Serum nesfatin-1 and HO-1 levels in the T2DM patients were lower, and apelin level was higher as compared with the control group. The levels of nesfatin-1 and HO-1 in the PDR group were the lowest, while the apelin level was the highest. Panretinal ISI in the PDR group was higher than that in the NPDR group(4.56±0.57 vs. 2.05±0.29, P&#x0026;#x003C;0.05). Correlation analysis found that serum nesfatin-1 and HO-1 levels were negatively correlated with panretinal ISI in patients with DR, while apelin level was positively correlated with panretinal ISI. The receiver operator characteristic(ROC)curve analysis found that the areas under the curves of serum nesfatin-1, apelin and HO-1 for predicting PDR were 0.842, 0.833 and 0.807 respectively.CONCLUSION:Serum nesfatin-1, apelin and HO-1 levels are closely related to the severity of DR. Dynamic monitoring of serum nesfatin-1, apelin and HO-1 levels is important for the early detection of PDR.

Effect of Glycyrrhizae Radix et Rhizoma-containing Serum on LPS-induced Inflammation in Caco2 Cells Based on Inhibition of Ferroptosis by Nrf2/HO-1 Pathway / 中国实验方剂学杂志

ObjectiveTo investigate the effect of Glycyrrhizae Radix et Rhizoma （GR）-containing serum on lipopolysaccharide （LPS）-induced inflammation in human colon epithelial adenocarcinoma cells （Caco2） based on inhibition of ferroptosis by the nuclear factor erythroid 2-related factor 2 （Nrf2）/heme oxygenase-1 （HO-1） pathway. MethodCaco2 cells were divided into a normal group， a model group （LPS， 200 μg·L-1）， low-， medium-， and high-dose GR-containing serum groups （5%， 10%， 20%）， and a ferroptosis inhibitor group （3-amino-4-cyclohexylamino-benzoic acid ethyl ester， Fer-1， 10 μmol·L-1）. The cells in the normal group were cultured normally， while those in other groups underwent the induction of an inflammation model. The cells in the low-， medium-， and high-dose GR-containing serum groups were treated with 5%， 10%， and 20% GR-containing serum for 24 hours， respectively， and the cells in the ferroptosis inhibitor group were treated with Fer-1 for 24 hours. Transmission electron microscopy was used to observe mitochondrial morphology in each group. Flow cytometry was used to detect intracellular Fe2+ levels. Microplate assays were performed to measure superoxide dismutase （SOD） activity， malondialdehyde （MDA） and glutathione peroxidase （GSH-Px） levels. Enzyme-linked immunosorbent assay （ELISA） was used to measure interleukin-1β （IL-1β）， IL-6， IL-10， and tumor necrosis factor-α （TNF-α） levels. Western blot was used to measure the expression levels of Nrf2， HO-1， ferritin heavy chain 1 （FTH1）， and glutathione peroxidase 4 （GSH-Px4） proteins. Small interfering RNA （siRNA） was used to investigate the role of Nrf2 in ferroptosis regulation. The cells after interference were divided into a negative control （NC） group， a Si-Nrf2 group， a GR-containing serum （20%） + Si-Nrf2 group， and a GR-containing serum （20%） + NC group. Microplate assays were performed to measure MDA， SOD， and GSH-Px levels， and Western blot was used to measure the expression levels of Nrf2， HO-1， FTH1， and GSH-Px4 proteins. ResultCompared with the normal group， the model group showed mitochondrial contraction， increased mitochondrial membrane thickness， and smaller mitochondrial morphology， increased Fe2+ content （P<0.01）， blunted SOD activity （P<0.01）， decreased GSH-Px expression （P<0.01）， increased MDA content （P<0.01）， reduced expression levels of Nrf2 and HO-1 （P<0.05）， reduced FTH1 expression （P<0.01）， and down-regulated GSH-Px4 expression （P<0.01）. In the GR-containing serum groups， the medium- and high-dose groups showed a significant decrease in Fe2+ content （P<0.01）， potentiated SOD and GSH-Px activities （P<0.01）， and decreased MDA levels （P<0.01）. The high-dose group showed a significant increase in Nrf2 expression （P<0.05）， and the medium-dose group showed increased expression of HO-1 and GSH-Px4 proteins （P<0.05）. The expression levels of FTH1 significantly increased in the low-， medium-， and high-dose groups （P<0.01）. The study on mechanism revealed that compared with the NC group， the cells transfected with Nrf2 siRNA showed increased MDA content （P<0.01）， blunted SOD activity （P<0.01）， decreased GSH-Px activity （P<0.01）， decreased expression of Nrf2 and HO-1 （P<0.01）， and reduced levels of FTH1 and GSH-Px4 proteins （P<0.01）. Compared with the Si-Nrf2 group， the cells treated with GR-containing serum showed a decrease in MDA content （P<0.01）， an increase in SOD activity （P<0.01）， an increase in GSH-Px activity （P<0.01）， increased expression of Nrf2 and FTH1 proteins （P<0.05）， and higher expression levels of HO-1 and GSH-Px4 proteins （P<0.01）. ConclusionGR-containing serum can reduce the inflammatory cytokines and oxidative stress levels in LPS-induced Caco2 cells. Its mechanism is related to the promotion of Nrf2/HO-1 signaling pathway expression， alleviating intracellular lipid peroxidation and inhibiting ferroptosis.

Role of Nrf2/HO-1 Signaling Pathway in Myocardial Infarction and Traditional Chinese Medicine Intervention： A Review / 中国实验方剂学杂志

Myocardial infarction （MI） is a common cardiovascular disease in clinical practice and one of the main causes of cardiovascular mortality. Its pathogenesis is complex and associated with oxidative stress reactions. Nuclear factor E2-related factor 2 （Nrf2） is a key factor in regulating oxidative stress reactions. It can regulate the expression of heme oxygenase-1 （HO-1）， playing a role in maintaining the oxidative-reductive homeostasis in the body. During the course of MI， the biological activity and levels of Nrf2 and HO-1 decrease， leading to weakened tissue antioxidant and anti-inflammatory capabilities， endothelial damage in myocardial blood vessels， release of vascular cell adhesion factors， and impaired endothelial function. In recent years， many basic research studies have explored the role and mechanisms of traditional Chinese medicine （TCM） in treating MI by modulating the Nrf2/HO-1 signaling pathway. The results have indicated that the Nrf2/HO-1 signaling pathway is an important potential target for TCM in the treatment of MI. This article reviewed the mechanism of the Nrf2/HO-1 signaling pathway in MI and the research progress of TCM in targeting and regulating this pathway， aiming to provide a theoretical basis for the prevention and treatment of MI and further drug development.