Heme oxygenase-1: redox regulation of a stress protein in lung and cell culture models

Oxidative stress in the brain-lung crosstalk: cellular and molecular perspectives

Oxidative stress is caused by an imbalance between the production of reactive oxygen species (ROS) and the body's ability to counteract their harmful effects, playing a key role in the pathogenesis of brain and lung-related diseases. This review comprehensively examines the intricate mechanisms by which oxidative stress influences cellular and molecular pathways, contributing to neurodegenerative, cardiovascular, and respiratory disorders. Emphasizing the detrimental effects on both brain and lung health, we discuss innovative diagnostic biomarkers, such as 8-hydroxy-2'-deoxyguanosine (8-OHdG), and the potential of antioxidant therapies. For these topics, we provide insights into future research directions in the field of oxidative stress treatment, including the development of personalized treatment approaches, the discovery and validation of novel biomarkers, and the development of new drug delivery systems. This review not only provides a new perspective on understanding the role of oxidative stress in brain and lung-related diseases but also offers new insights for future clinical treatments.

Sildenafil delays bone remodeling of fractured femora in aged mice by reducing the number and activity of osteoclasts within the callus tissue

The elderly exhibit a reduced healing capacity after fracture, which is often associated with delayed or failed bone healing. This is due to a plethora of factors, such as an impaired bone vascular system and delayed angiogenesis. The phosphodiesterase-5 (PDE-5) inhibitor sildenafil exerts pro-angiogenic and pro-osteogenic effects. Hence, we herein investigated in aged mice whether sildenafil can improve fracture healing. For this purpose, 40 aged CD-1 mice (16-18 months) were daily treated with 5 mg/kg body weight sildenafil (n = 20) or vehicle (control, n = 20) by oral gavage. The callus tissue of their femora was analyzed at 2 and 5 weeks after fracture by X-ray, biomechanics, micro-computed tomography (µCT), histology, immunohistochemistry as well as Western blotting. These analyses revealed a significantly increased bone volume and higher ratio of callus to femoral bone diameter in sildenafil-treated mice at 5 weeks after fracture when compared to controls. This was associated with a reduced number and activity of osteoclasts at 2 weeks after fracture, most likely caused by an increased expression of osteoprotegerin (OPG). Taken together, these findings indicate that sildenafil does not improve fracture healing in the elderly but delays the process of bone remodeling most likely by reducing the number and activity of osteoclasts within the callus tissue.

On the Question of CO's Ability to Induce HO-1 Expression in Cell Culture: A Comparative Study Using Different CO Sources

With the recognition of the endogenous signaling roles and pharmacological functions of carbon monoxide (CO), there is an increasing need to understand CO's mechanism of actions. Along this line, chemical donors have been introduced as CO surrogates for ease of delivery, dosage control, and sometimes the ability to target. Among all of the donors, two ruthenium-carbonyl complexes, CORM-2 and -3, are arguably the most commonly used tools for about 20 years in studying the mechanism of actions of CO. Largely based on data using these two CORMs, there has been a widely accepted inference that the upregulation of heme oxygenase-1 (HO-1) expression is one of the key mechanisms for CO's actions. However, recent years have seen reports of very pronounced chemical reactivities and CO-independent activities of these CORMs. We are interested in examining this question by conducting comparative studies using CO gas, CORM-2/-3, and organic CO donors in RAW264.7, HeLa, and HepG2 cell cultures. CORM-2 and CORM-3 treatment showed significant dose-dependent induction of HO-1 compared to "controls," while incubation for 6 h with 250-500 ppm CO gas did not increase the HO-1 protein expression and mRNA transcription level. A further increase of the CO concentration to 5% did not lead to HO-1 expression either. Additionally, we demonstrate that CORM-2/-3 releases minimal amounts of CO under the experimental conditions. These results indicate that the HO-1 induction effects of CORM-2/-3 are not attributable to CO. We also assessed two organic CO prodrugs, BW-CO-103 and BW-CO-111. BW-CO-111 but not BW-CO-103 dose-dependently increased HO-1 levels in RAW264.7 and HeLa cells. We subsequently studied the mechanism of induction with an Nrf2-luciferase reporter assay, showing that the HO-1 induction activity is likely due to the activation of Nrf2 by the CO donors. Overall, CO alone is unable to induce HO-1 or activate Nrf2 under various conditions in vitro. As such, there is no evidence to support attributing the HO-1 induction effect of the CO donors such as CORM-2/-3 and BW-CO-111 in cell culture to CO. This comparative study demonstrates the critical need to consider possible CO-independent effects of a chemical CO donor before attributing the observed biological effects to CO. It is also important to note that such in vitro results cannot be directly extrapolated to in vivo studies because of the increased level of complexity and the likelihood of secondary and/or synergistic effects in the latter.

Investigation of the effects of crocin on inflammation, oxidative stress, apoptosis, NF-κB, TLR-4 and Nrf-2/HO-1 pathways in gentamicin-induced nephrotoxicity in rats

The primary limitation of gentamicin (Gm) treatment is its potential to induce nephrotoxicity, which can restrict both its duration and efficacy. This study aims to investigate the protective effects of Crocin (Cr) against Gm-induced nephrotoxicity and its underlying mechanisms, including inflammation, apoptosis, TLR-4, Nrf-2/HO-1 pathways. 36 Sprague Dawley rats were divided into 6 groups for the study. Group I received only saline. Groups II and III were administered 25 and 50 mg/kg of crocin, respectively. Group IV was treated with 80 mg/kg of Gm. Groups V and VI received 25 and 50 mg/kg of crocin, respectively, in addition to Gm administration. Crocin demonstrated protective effects on kidney tissue. It down-regulated the genes NF-κB, COX-2, TLR-4, Bax, and Caspase-3, while up-regulating Bcl-2, Nrf-2, and HO-1. In conclusion, these findings hold promise for the prevention of Gm-induced nephrotoxicity through the modulation of the Nrf-2/HO-1 pathway.

GPR68-ATF4 signaling is a novel prosurvival pathway in glioblastoma activated by acidic extracellular microenvironment

BACKGROUND

Glioblastoma multiforme (GBM) stands as a formidable challenge in oncology because of its aggressive nature and severely limited treatment options. Despite decades of research, the survival rates for GBM remain effectively stagnant. A defining hallmark of GBM is a highly acidic tumor microenvironment, which is thought to activate pro-tumorigenic pathways. This acidification is the result of altered tumor metabolism favoring aerobic glycolysis, a phenomenon known as the Warburg effect. Low extracellular pH confers radioresistant tumors to glial cells. Notably GPR68, an acid sensing GPCR, is upregulated in radioresistant GBM. Usage of Lorazepam, which has off target agonism of GPR68, is linked to worse clinical outcomes for a variety of cancers. However, the role of tumor microenvironment acidification in GPR68 activation has not been assessed in cancer. Here we interrogate the role of GPR68 specifically in GBM cells using a novel highly specific small molecule inhibitor of GPR68 named Ogremorphin (OGM) to induce the iron mediated cell death pathway: ferroptosis.

METHOD

OGM was identified in a non-biased zebrafish embryonic development screen and validated with Morpholino and CRISPR based approaches. Next, A GPI-anchored pH reporter, pHluorin2, was stably expressed in U87 glioblastoma cells to probe extracellular acidification. Cell survival assays, via nuclei counting and cell titer glo, were used to demonstrate sensitivity to GPR68 inhibition in twelve immortalized and PDX GBM lines. To determine GPR68 inhibition's mechanism of cell death we use DAVID pathway analysis of RNAseq. Our major indication, ferroptosis, was then confirmed by western blotting and qRT-PCR of reporter genes including TFRC. This finding was further validated by transmission electron microscopy and liperfluo staining to assess lipid peroxidation. Lastly, we use siRNA and CRISPRi to demonstrate the critical role of ATF4 suppression via GPR68 for GBM survival.

RESULTS

We used a pHLourin2 probe to demonstrate how glioblastoma cells acidify their microenvironment to activate the commonly over expressed acid sensing GPCR, GPR68. Using our small molecule inhibitor OGM and genetic means, we show that blocking GPR68 signaling results in robust cell death in all thirteen glioblastoma cell lines tested, irrespective of genetic and phenotypic heterogeneity, or resistance to the mainstay GBM chemotherapeutic temozolomide. We use U87 and U138 glioblastoma cell lines to show how selective induction of ferroptosis occurs in an ATF4-dependent manner. Importantly, OGM was not-acutely toxic to zebrafish and its inhibitory effects were found to spare non-malignant neural cells.

CONCLUSION

These results indicate GPR68 emerges as a critical sensor for an autocrine pro-tumorigenic signaling cascade triggered by extracellular acidification in glioblastoma cells. In this context, GPR68 suppresses ATF4, inhibition of GPR68 increases expression of ATF4 which leads to ferroptotic cell death. These findings provide a promising therapeutic approach to selectively induce ferroptosis in glioblastoma cells while sparing healthy neural tissue.

Andrographolide induced heme oxygenase-1 expression in MSC-like cells isolated from rat bone marrow exposed to environmental stress

BACKGROUND AND OBJECTIVES

Mesenchymal stem cells (MSC-like cells) are the most important stem cells that are used in transplantation clinically in various applications. The survival rate of MSC-like cells is strongly reduced due to adverse conditions in the microenvironment of transplantation, including environmental stress. Heme oxygenase-1 (HO-1) is a member of the heat shock protein, as well as a stress-induced enzyme, present throughout the body. The present study was conducted to investigate the effect of andrographolide, an active derivative from andrographolide paniculate, on HO-1 expression in mesenchymal stem cells derived from rat bone marrow.

MATERIALS AND METHODS

The rat bone marrow-derived mesenchymal stem cells (BMSC-like cells) were extracted and proliferated in several passages. The identity of MSC-like cells was confirmed by morphological observations and differential tests. The flow cytometry method was used to verify the MSC-specific markers. Isolated MSC-like cells were treated with different concentrations of andrographolide and then exposed to environmental stress. Cell viability was assessed using the MTT colorimetric assay. A real-time PCR technique was employed to evaluate the expression level of HO-1 in the treated MSC-like cells.

RESULTS

Isolated MSC-like cells demonstrated fibroblast-like morphology. These cells in different culture mediums differentiated into osteocytes and adipocytes and were identified using alizarin red and oil red staining, respectively. As well, MSC-like cells were verified by the detection of CD105 surface antigen and the absence of CD14 and CD45 antigens. The results of the MTT assay showed that the pre-treatment of MSC-like cells with andrographolide concentration independently increased the viability and resistance of these cells to environmental stress caused by hydrogen peroxide and serum deprivation (SD). Real-time PCR findings indicated a significant increase in HO-1 gene expression in the andrographolide-receiving groups (p < 0.01).

CONCLUSION

Our results suggest that andrographolide creates a promising strategy for enhancing the quality of cell therapy by increasing the resistance of MSC-like cells to environmental stress and inducing the expression of HO-1.

Induction of heme oxygenase-1 antagonizes PM2.5-induced pulmonary VEGFA expression through regulating HIF-1α

Particulate matter (PM) 2.5 has long been regarded as a major risk factor of the respiratory system, which constitutes a threat to human health. Although the positive relationship between PM2.5 exposure and the development of respiratory diseases has been well established, limited studies investigate the intrinsic self-protection mechanisms against PM2.5-induced respiratory injuries. Excessive pulmonary inflammation served as a key pathogenic mechanism in PM2.5-induced airway dysfunction, and we have previously shown that PM2.5 induced the production of vascular endothelial growth factor A (VEGFA) in the bronchial epithelial cells, which subsequently led to pulmonary inflammatory responses. In the current study, we found that PM2.5 also concurrently induced the expression of the stress-responsive protein heme oxygenase-1 (HO-1) along with VEGFA in the bronchial epithelial cells both in vivo and in vitro. Importantly, knocking down of HO-1 expression significantly increased the synthesis and secretion of VEGFA; while overexpression of HO-1 showed the opposite effects, indicating that HO-1 induction can antagonize VEGFA production in the bronchial epithelial cells upon PM2.5 exposure. Mechanistically, HO-1 inhibited PM2.5-evoked VEGFA induction through modulating hypoxia-inducible factor 1 alpha (HIF-1α), which was the upstream transcriptional factor of VEGFA. More specifically, HO-1 could not only inhibit HIF-1α expression, but also suppress its transactivity. Taken together, our results suggested that HO-1 was an intrinsic protective factor against PM2.5-induced pulmonary VEGFA production with a mechanism relating to HIF-1α, thus providing a potential treatment strategy against PM2.5 triggered airway injuries.

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 GSK3β (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)-1β, 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-1β, 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.

Critical role of heme oxygenase-1 in chaetoglobosin A by triggering reactive oxygen species mediated mitochondrial apoptosis in colorectal cancer

The incidence rate of colorectal cancer (CRC) has been increasing and poses severe threats to human health worldwide and developing effective treatment strategies remains an urgent task. In this study, Chaetoglobosin A (ChA), an endophytic fungal metabolite from the medicinal herb-derived fungus Chaetomium globosum Km1126, was identified as a potent and selective antitumor agent in human CRC. ChA induced growth inhibition of CRC cells in a concentration-dependent manner but did not impair the viability of normal colon cells. ChA triggered mitochondrial intrinsic and caspase-dependent apoptotic cell death. In addition, apoptosis antibody array analysis revealed that expression of Heme oxygenase-1 (HO-1) was significantly increased by ChA. Inhibition of HO-1 increased the sensitivity of CRC cells to ChA, suggesting HO-1 may play a protective role in ChA-mediated cell death. ChA induced cell apoptosis via the induction of reactive oxygen species (ROS) and ROS scavenger (NAC) prevented ChA-induced cell death, mitochondrial dysfunction, and HO-1 activation. ChA promoted the activation of c-Jun N-terminal kinase (JNK), and co-administration of JNK inhibitor or siRNA markedly reversed ChA-mediated apoptosis. ChA significantly decreased the tumor growth without eliciting any organ toxicity or affecting the body weight of the CRC xenograft mice. This is the first study to demonstrate that ChA exhibits promising anti-cancer properties against human CRC both in vitro and in vivo. ChA is a potential therapeutic agent worthy of further development in clinical trials for cancer treatment.

Phloroglucinol possesses anti-inflammatory activities by regulating AMPK/Nrf2/HO-1 signaling pathway in LPS-stimulated RAW264.7 murine macrophages

BACKGROUND

Inflammation is closely related to the pathogenesis of chronic illnesses. Secondary metabolites of marine seaweeds are recognized as reliable sources of bioactive compounds due to their health benefits besides their nutritional value. The objective of this study was to determine the potential anti-inflammatory effect of phloroglucinol (Phl) in RAW264.7 murine macrophages after lipopolysaccharides (LPS) stimulation.

METHODS

MTT, nitric oxide (NO), and DCFH-DA assays were conducted to determine cell viability, NO production, and reactive oxygen species (ROS) generation respectively. Pro-inflammatory cytokines and prostaglandin E2 (PGE2) levels were measured using ELISA assay kits. Protein expression levels were determined by western blot analysis.

RESULTS

Phl treatment showed a promising anti-inflammatory effect by reducing NO production, secretion of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), PGE2 production, protein expression levels of inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2), and ROS generation in LPS-stimulated RAW264.7 murine macrophages. Phl treatment upregulated heme oxygenase-1 (HO-1) expression by inducing nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and activating AMPK. However, Zinc protoporphyrin (ZnPP), an inhibitor of HO-1, partially reversed these effects, including NO production, pro-inflammatory cytokine secretion, iNOS, COX-2 and HO-1 expression, and ROS generation.

CONCLUSION

Phl has potential anti-inflammatory activities by regulating AMPK/Nrf2/HO-1 pathway in LPS-stimulated RAW264.7 murine macrophages.

Fenofibrate Decreases Ethanol-Induced Neuroinflammation and Oxidative Stress and Reduces Alcohol Relapse in Rats by a PPAR-α-Dependent Mechanism

High ethanol consumption triggers neuroinflammation, implicated in sustaining chronic alcohol use. This inflammation boosts glutamate, prompting dopamine release in reward centers, driving prolonged drinking and relapse. Fibrate drugs, activating peroxisome proliferator-activated receptor alpha (PPAR-α), counteract neuroinflammation in other contexts, prompting investigation into their impact on ethanol-induced inflammation. Here, we studied, in UChB drinker rats, whether the administration of fenofibrate in the withdrawal stage after chronic ethanol consumption reduces voluntary intake when alcohol is offered again to the animals (relapse-type drinking). Furthermore, we determined if fenofibrate was able to decrease ethanol-induced neuroinflammation and oxidative stress in the brain. Animals treated with fenofibrate decreased alcohol consumption by 80% during post-abstinence relapse. Furthermore, fenofibrate decreased the expression of the proinflammatory cytokines tumor necrosis factor-alpha (TNF-α) and interleukins IL-1β and IL-6, and of an oxidative stress-induced gene (heme oxygenase-1), in the hippocampus, nucleus accumbens, and prefrontal cortex. Animals treated with fenofibrate showed an increase M2-type microglia (with anti-inflammatory proprieties) and a decrease in phagocytic microglia in the hippocampus. A PPAR-α antagonist (GW6471) abrogated the effects of fenofibrate, indicating that they are dependent on PPAR-α activation. These findings highlight the potential of fenofibrate, an FDA-approved dyslipidemia medication, as a supplementary approach to alleviating relapse severity in individuals with alcohol use disorder (AUD) during withdrawal.

Heme Oxygenase-1 and Its Metabolites Carbon Monoxide and Biliverdin, but Not Iron, Exert Antiviral Activity against Porcine Circovirus Type 3

Porcine circovirus type 3 (PCV3) is a newly discovered pathogen that causes porcine dermatitis and nephropathy syndrome (PDNS)-like clinical signs, multisystemic inflammation, and reproductive failure. Heme oxygenase-1 (HO-1), a stress-inducible enzyme, exerts protective functions by converting heme into carbon monoxide (CO), biliverdin (BV), and iron. However, the effects of HO-1 and its metabolites on PCV3 replication remain unknown. In this study, experiments involving specific inhibitors, lentivirus transduction, and small interfering RNA (siRNA) transfection revealed that active PCV3 infection reduced HO-1 expression and that the expression of HO-1 negatively regulated virus replication in cultured cells, depending on its enzymatic activity. Subsequently, the effects of the HO-1 metabolites (CO, BV, and iron) on PCV3 infection were investigated. The CO inducers (cobalt protoporphyrin IX [CoPP] or tricarbonyl dichloro ruthenium [II] dimer [CORM-2]) mediate PCV3 inhibition by generating CO, and this inhibition is reversed by hemoglobin (Hb; a CO scavenger). The inhibition of PCV3 replication by BV depended on BV-mediated reactive oxygen species (ROS) reduction, as N-acetyl-l-cysteine affected PCV3 replication while reducing ROS production. The reduction product of BV, bilirubin (BR), specifically promoted nitric oxide (NO) generation and further activated the cyclic GMP/protein kinase G (cGMP/PKG) pathway to attenuate PCV3 infection. Both the iron provided by FeCl3 and the iron chelated by deferoxamine (DFO) with CoPP treatment failed to affect PCV3 replication. Our data demonstrate that the HO-1-CO-cGMP/PKG, HO-1-BV-ROS, and HO-1-BV-BR-NO-cGMP/PKG pathways contribute crucially to the inhibition of PCV3 replication. These results provide important insights regarding preventing and controlling PCV3 infection. IMPORTANCE The regulation of host protein expression by virus infection is the key to facilitating self-replication. As an important emerging pathogen of swine, clarification of the interaction between PCV3 infection and the host enables us to understand the viral life cycle and pathogenesis better. Heme oxygenase-1 (HO-1) and its metabolites carbon monoxide (CO), biliverdin (BV), and iron have been demonstrated to involve a wealth of viral replications. Here, we, for the first time, demonstrated that HO-1 expression decreases in PCV3-infected cells and negatively regulates PCV3 replication and that the HO-1 metabolic products CO and BV inhibit PCV3 replication by the CO- or BV/BR/NO-dependent cGMP/PKG pathway or BV-mediated ROS reduction, but the iron (the third metabolic product) does not. Specifically, PCV3 infection maintains normal proliferation by downregulating HO-1 expression. These findings clarify the mechanism by which HO-1 modulates PCV3 replication in cells and provide important targets for preventing and controlling PCV3 infection.

Protective effect of curcumin on hepatolenticular degeneration through copper excretion and inhibition of ferroptosis

BACKGROUND

Hepatolenticular degeneration (HLD) is an autosomal recessive disorder concerning copper metabolism. Copper overload is also accompanied by iron overload in HLD patients, which can lead to ferroptosis. Curcumin, the active component in turmeric, has the potential to inhibit ferroptosis.

PURPOSE

The current study proposed a systematic investigation of the protective effects of curcumin against HLD and the underlying mechanisms.

METHODS

The protective effect of curcumin on toxic milk (TX) mice was studied. Liver tissue was observed via hematoxylin-eosin (H&E) staining and the ultrastructure of the liver tissue was observed through transmission electron microscopy. Copper levels in the tissues, serum, and metabolites were measured by atomic absorption spectrometry (AAS). In addition, serum and liver indicators were evaluated. In cellular experiments, the effect of curcumin on the viability of rat normal liver cells (BRL-3A) was determined via the 3-[4,5-dimethylthiazol-2-yl)]-2,5-diphenyltetrazolium bromide (MTT) assay. Cell and mitochondrial morphology were observed in curcumin-mediated HLD model cells. The intracellular copper ion fluorescence intensity was observed via fluorescence microscopy, and intracellular copper iron content was detected using AAS. Further, oxidative stress indicators were evaluated. Cellular reactive oxygen species (ROS) and cellular mitochondrial membrane potential were examined via flow cytometry. Furthermore, the expression levels of nuclear factor erythroid-2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and glutathione peroxidase 4 (GPX4) were determined via western blotting (WB).

RESULTS

The histopathology of the liver confirmed the hepatoprotective effects of curcumin. Curcumin improved copper metabolism in TX mice. Both serum liver enzyme markers and antioxidant enzyme levels indicated the protective effect of curcumin against HLD-related liver injury. The MTT assay results showed that curcumin was protective against excess copper-induced injury. Curcumin improved the morphology of HLD model cells and their mitochondrial morphology. The Cu²⁺ fluorescent probe and the AAS results indicated that curcumin reduced Cu²⁺ content in HLD hepatocytes. In addition, curcumin improved oxidative stress levels and prevented the decline of mitochondrial membrane potential in HLD model cells. The ferroptosis inducer Erastin reversed these effects of curcumin. WB revealed that curcumin promoted Nrf2, HO-1, and GPX4 protein expression in HLD model cells, and the Nrf2 inhibitor ML385 reversed the effects of curcumin.

CONCLUSION

Curcumin demonstrates a protective role by expelling copper and inhibiting ferroptosis, activating the Nrf2/HO-1/GPX4 signaling pathway in HLD.

Genome-wide expression analysis reveals different heat shock responses in indigenous (Bos indicus) and crossbred (Bos indicus X Bos taurus) cattle

Environmental heat stress in dairy cattle leads to poor health, reduced milk production and decreased reproductive efficiency. Multiple genes interact and coordinate the response to overcome the impact of heat stress. The present study identified heat shock regulated genes in the peripheral blood mononuclear cells (PBMC). Genome-wide expression patterns for cellular stress response were compared between two genetically distinct groups of cattle viz., Hariana (B. indicus) and Vrindavani (B. indicus X B. taurus). In addition to major heat shock response genes, oxidative stress and immune response genes were also found to be affected by heat stress. Heat shock proteins such as HSPH1, HSPB8, FKB4, DNAJ4 and SERPINH1 were up-regulated at higher fold change in Vrindavani compared to Hariana cattle. The oxidative stress response genes (HMOX1, BNIP3, RHOB and VEGFA) and immune response genes (FSOB, GADD45B and JUN) were up-regulated in Vrindavani whereas the same were down-regulated in Hariana cattle. The enrichment analysis of dysregulated genes revealed the biological functions and signaling pathways that were affected by heat stress. Overall, these results show distinct cellular responses to heat stress in two different genetic groups of cattle. This also highlight the long-term adaptation of B. indicus (Hariana) to tropical climate as compared to the crossbred (Vrindavani) with mixed genetic makeup (B. indicus X B. taurus).

Analysis of Single- and Double-Stranded DNA Damage in Osteoblastic Cells after Hyperbaric Oxygen Exposure

(1) Background: Hyperbaric oxygen (HBO) exposure induces oxidative stress that may lead to DNA damage, which has been observed in human peripheral blood lymphocytes or non-human cells. Here, we investigated the impact of hyperbaric conditions on two human osteoblastic cell lines: primary human osteoblasts, HOBs, and the osteogenic tumor cell line SAOS-2. (2) Methods: Cells were exposed to HBO in an experimental hyperbaric chamber (4 ATA, 100% oxygen, 37 °C, and 4 h) or sham-exposed (1 ATA, air, 37 °C, and 4 h). DNA damage was examined before, directly after, and 24 h after exposure with an alkaline comet assay and detection of γH2AX+53BP1 colocalizing double-strand break (DSB) foci and apoptosis. The gene expression of TGFß-1, HO-1, and NQO1, involved in antioxidative functions, was measured with qRT-PCR. (3) Results: The alkaline comet assay showed significantly elevated levels of DNA damage in both cell lines after 4 h of HBO, while the DSB foci were similar to sham. γH2AX analysis indicated a slight increase in apoptosis in both cell lines. The increased expression of HO-1 in HOB and SAOS-2 directly after exposure suggested the induction of an antioxidative response in these cells. Additionally, the expression of TGF-ß1 was negatively affected in HOB cells 4 h after exposure. (4) Conclusions: in summary, this study indicates that osteoblastic cells are sensitive to the DNA-damaging effects of hyperbaric hyperoxia, with the HBO-induced DNA damage consisting largely of single-strand DNA breaks that are rapidly repaired.

The prognostic and therapeutic potential of HO-1 in leukemia and MDS

BACKGROUND

Heme oxygenase-1 (HO-1), a heme-degrading enzyme, is proven to have anti-apoptotic effects in several malignancies. In addition, HO-1 is reported to cause chemoresistance and increase cell survival. Growing evidence indicates that HO-1 contributes to the course of hematological malignancies as well. Here, the expression pattern, prognostic value, and the effect of HO-1 targeting in HMs are discussed.

MAIN BODY

According to the recent literature, it was discovered that HO-1 is overexpressed in myelodysplastic syndromes (MDS), chronic myeloid leukemia (CML), acute myeloblastic leukemia (AML), and acute lymphoblastic leukemia (ALL) cells and is associated with high-risk disease. Furthermore, in addition to HO-1 expression by leukemic and MDS cells, CML, AML, and ALL leukemic stem cells express this protein as well, making it a potential target for eliminating minimal residual disease (MRD). Moreover, it was concluded that HO-1 induces tumor progression and prevents apoptosis through various pathways.

CONCLUSION

HO-1 has great potential in determining the prognosis of leukemia and MDS patients. HO-1 induces resistance to several chemotherapeutic agents as well as tyrosine kinase inhibitors and following its inhibition, chemo-sensitivity increases. Moreover, the exact role of HO-1 in Chronic Lymphocytic Leukemia (CLL) is yet unknown. While findings illustrate that MDS and other leukemic patients could benefit from HO-1 targeting. Future studies can help broaden our knowledge regarding the role of HO-1 in MDS and leukemia. Video abstract.

PFKFB4 Drives the Oncogenicity in TP53-Mutated Hepatocellular Carcinoma in a Phosphatase-Dependent Manner

BACKGROUND & AIMS

Metabolic reprogramming is recognized as a cancer hallmark intimately linked to tumor hypoxia, which supports rapid tumor growth and mitigates the consequential oxidative stress. Phosphofructokinase-fructose bisphosphatase (PFKFB) is a family of bidirectional glycolytic enzymes possessing both kinase and phosphatase functions and has emerged as important oncogenes in multiple types of cancer. However, its clinical relevance, functional significance, and underlying mechanistic insights in hepatocellular carcinoma (HCC), the primary malignancy that develops in the most important metabolic organ, has never been addressed.

METHODS

PFKFB4 expression was examined by RNA sequencing in The Cancer Genome Atlas and our in-house HCC cohort. The up-regulation of PFKFB4 expression was confirmed further by quantitative polymerase chain reaction in an expanded hepatitis B virus-associated HCC cohort followed by clinicopathologic correlation analysis. CRISPR/Cas9-mediated PFKFB4 knockout cells were generated for functional characterization in vivo, targeted metabolomic profiling, as well as RNA sequencing analysis to comprehensively examine the impact of PFKFB4 loss in HCC.

RESULTS

PFKFB4 expression was up-regulated significantly in HCC and correlated positively with TP53 and TSC2 loss-of-function mutations. In silico transcriptome-based analysis further revealed PFKFB4 functions as a critical hypoxia-inducible gene. Clinically, PFKFB4 up-regulation was associated with more aggressive tumor behavior. Functionally, CRISPR/Cas9-mediated PFKFB4 knockout significantly impaired in vivo HCC development. Targeted metabolomic profiling revealed that PFKFB4 functions as a phosphatase in HCC and its ablation caused an accumulation of metabolites in downstream glycolysis and the pentose phosphate pathway. In addition, PFKFB4 loss induced hypoxia-responsive genes in glycolysis and reactive oxygen species detoxification. Conversely, ectopic PFKFB4 expression conferred sorafenib resistance.

CONCLUSIONS

PFKFB4 up-regulation supports HCC development and posed therapeutic implications.

Nanoscale coordination polymers enabling antioxidants inhibition for enhanced chemodynamic therapy

Reactive oxygen species (ROS) generation to induce cell death is an effective strategy for cancer therapy. In particular, chemodynamic therapy (CDT), using Fenton-type reactions to generate highly cytotoxic hydroxyl radical (•OH), is a promising treatment modality. However, the therapeutic efficacy of ROS-based cancer treatment is still limited by some critical challenges, such as overexpression of enzymatic and non-enzymatic antioxidants by tumor cells, as well as the low tumor targeting efficiency of therapeutic agents. To address those problems, biomimetic CuZn protoporphyrin IX nanoscale coordination polymers have been developed, which significantly amplify oxidative stress against tumors by simultaneously inhibiting enzymatic and non-enzymatic antioxidants and initiating the CDT. In this design, cancer cell membrane camouflaged nanoparticle exhibits an excellent homotypic targeting effect. After being endocytosed into tumor cells, the nanoparticles induce depletion of the main non-enzymatic antioxidant glutathione (GSH) by undergoing a redox reaction with GSH. Afterward, the redox reaction generated cuprous ion (Cu⁺) works as a CDT agent for •OH generation. Furthermore, the released Zn protoporphyrin IX strongly inhibits the activity of the typical enzymatic antioxidant heme oxygenase-1. This tetra-modal synergistic strategy endows the biomimetic nanoparticles with great capability for anticancer therapy, which has been demonstrated in both in vitro and in vivo studies.

Fatty Liver/Adipose Tissue Dual-Targeting Nanoparticles with Heme Oxygenase-1 Inducer for Amelioration of Obesity, Obesity-Induced Type 2 Diabetes, and Steatohepatitis

Persistent uptake of high-calorie diets induces the storage of excessive lipid in visceral adipose tissue. Lipids secreted from obese adipose tissue are accumulated in peripheral tissues such as the liver, pancreas, and muscle, and impair insulin sensitivity causing type 2 diabetes mellitus (T2DM). Furthermore, the accumulation of inflammatory cytokines and lipids in the liver induces apoptosis and fibrogenesis, and ultimately causes nonalcoholic steatohepatitis (NASH). To modulate obese tissue environments, it is challenged to selectively deliver inducers of heme oxygenase-1 (HO-1) to adipose tissue with the aid of a prohibitin targeting drug delivery system. Prohibitin binding peptide (PBP), an oligopeptide targeting prohibitin rich in adipose tissue, is conjugated on the surface of Hemin- or CoPP-loaded poly(lactide-co-glycolide) nanoparticles (PBP-NPs). PBP-NPs efficiently differentiate lipid storing white adipocytes into energy-generating brown adipocytes in T2DM and NASH models. In addition, PBP-NPs are found to target prohibitin overexpressed fatty liver in the NASH model and inhibit hepatic uptake of circulating lipids. Furthermore, PBP-NPs switch phenotypes of inflammatory macrophages in damaged organs and lower inflammation. Taken together, dual-targeted induction of HO-1 in fatty adipose and liver tissues is proven to be a promising therapeutic strategy to ameliorate obesity, insulin resistance, and steatohepatitis by lowering lipids and cytokines.

Gambogic Acid Induces HO-1 Expression and Cell Apoptosis through p38 Signaling in Oral Squamous Cell Carcinoma

Gambogic acid (GA), a natural and bioactive compound from the gamboge resin, has been reported to exhibit many oncostatic activities against several types of malignancies. However, its effects on the progression of oral squamous cell carcinoma (OSCC) remain largely unexplored. To fill this gap, we investigated the anticancer role of GA and molecular mechanisms underlying GA's actions in combating oral cancer. We found that GA negatively regulated the viability of OSCC cells, involving induction of the sub-G1 phase and cell apoptosis. In addition, a specific signature of apoptotic proteome, such as upregulation of heme oxygenase-1 (HO-1) and activation of caspase cascades, was identified in GA-treated OSCC. Moreover, such induction of HO-1 expression and caspase cleavage by GA was significantly diminished through the pharmacological inhibition of p38 kinase. In conclusion, these results demonstrate that GA promotes cell apoptosis in OSCC, accompanied with the activation of a p38-dependent apoptotic pathway. Our findings provide potential avenues for the use of GA with high safety and therapeutic implications in restraining oral cancer.

ASC-J9 Blocks Cell Proliferation and Extracellular Matrix Production of Keloid Fibroblasts through Inhibiting STAT3 Signaling

Keloids are a fibrotic skin disorder caused by abnormal wound healing and featuring the activation and expansion of fibroblasts beyond the original wound margin. Signal transducer and activator of transcription 3 (STAT3) has been found to mediate the biological functions of keloid fibroblasts (KFs). Therefore, we aimed to demonstrate whether ASC-J9, an inhibitor of STAT3 phosphorylation, can suppress the activation of KFs. Western blotting results showed that ASC-J9 inhibited the levels of COL1A1 and FN1 proteins, which were upregulated in KFs, by decreasing the expression of pSTAT3 and STAT3. RNA sequencing and in vitro studies further demonstrated that ASC-J9 treatment of KFs reduced cell division, inflammation, and ROS generation, as well as extracellular matrix (ECM) synthesis. ELISA assays verified that ASC-J9 treatment significantly mitigated IL-6 protein secretion in KFs. Transmission electron microscopy images revealed that ASC-J9 induced the formation of multilamellar bodies in KFs, which is associated with autophagy-related signaling. These results suggested that inhibiting a vicious cycle of the ROS/STAT3/IL-6 axis by ASC-J9 may represent a potential therapeutic approach to suppress cell proliferation and ECM production in KFs.

Repurposing Multiple-Molecule Drugs for COVID-19-Associated Acute Respiratory Distress Syndrome and Non-Viral Acute Respiratory Distress Syndrome via a Systems Biology Approach and a DNN-DTI Model Based on Five Drug Design Specifications

The coronavirus disease 2019 (COVID-19) epidemic is currently raging around the world at a rapid speed. Among COVID-19 patients, SARS-CoV-2-associated acute respiratory distress syndrome (ARDS) is the main contribution to the high ratio of morbidity and mortality. However, clinical manifestations between SARS-CoV-2-associated ARDS and non-SARS-CoV-2-associated ARDS are quite common, and their therapeutic treatments are limited because the intricated pathophysiology having been not fully understood. In this study, to investigate the pathogenic mechanism of SARS-CoV-2-associated ARDS and non-SARS-CoV-2-associated ARDS, first, we constructed a candidate host-pathogen interspecies genome-wide genetic and epigenetic network (HPI-GWGEN) via database mining. With the help of host-pathogen RNA sequencing (RNA-Seq) data, real HPI-GWGEN of COVID-19-associated ARDS and non-viral ARDS were obtained by system modeling, system identification, and Akaike information criterion (AIC) model order selection method to delete the false positives in candidate HPI-GWGEN. For the convenience of mitigation, the principal network projection (PNP) approach is utilized to extract core HPI-GWGEN, and then the corresponding core signaling pathways of COVID-19-associated ARDS and non-viral ARDS are annotated via their core HPI-GWGEN by KEGG pathways. In order to design multiple-molecule drugs of COVID-19-associated ARDS and non-viral ARDS, we identified essential biomarkers as drug targets of pathogenesis by comparing the core signal pathways between COVID-19-associated ARDS and non-viral ARDS. The deep neural network of the drug–target interaction (DNN-DTI) model could be trained by drug–target interaction databases in advance to predict candidate drugs for the identified biomarkers. We further narrowed down these predicted drug candidates to repurpose potential multiple-molecule drugs by the filters of drug design specifications, including regulation ability, sensitivity, excretion, toxicity, and drug-likeness. Taken together, we not only enlighten the etiologic mechanisms under COVID-19-associated ARDS and non-viral ARDS but also provide novel therapeutic options for COVID-19-associated ARDS and non-viral ARDS.

Coffee-Derived Phenolic Compounds Activate Nrf2 Antioxidant Pathway in I/R Injury In Vitro Model: A Nutritional Approach Preventing Age Related-Damages

Age-related injuries are often connected to alterations in redox homeostasis. The imbalance between free radical oxygen species and endogenous antioxidants defenses could be associated with a growing risk of transient ischemic attack and stroke. In this context, a daily supply of dietary antioxidants could counteract oxidative stress occurring during ischemia/reperfusion injury (I/R), preventing brain damage. Here we investigated the potential antioxidant properties of coffee-derived circulating metabolites and a coffee pulp phytoextract, testing their efficacy as ROS scavengers in an in vitro model of ischemia. Indeed, the coffee fruit is an important source of phenolic compounds, such as chlorogenic acids, present both in the brewed seed and in the discarded pulp. Therefore, rat brain endothelial cells, subjected to oxygen and glucose deprivation (OGD) and recovery (ogR) to mimic reperfusion, were pretreated or not with coffee by-products. The results indicate that, under OGD/ogR, the ROS accumulation was reduced by coffee by-product. Additionally, the coffee extract activated the Nrf2 antioxidant pathway via Erk and Akt kinases phosphorylation, as shown by increased Nrf2 and HO-1 protein levels. The data indicate that the daily intake of coffee by-products as a dietary food supplement represents a potential nutritional strategy to counteract aging.

Novelkaraya gum micro-particles loaded Ganoderma lucidum polysaccharide regulate sex hormones, oxidative stress and inflammatory cytokine levels in cadmium induced testicular toxicity in experimental animals

Presented research aimed to develop a spray drying process without the use of organic solvents for the preparation of novel Karaya gum polymer microparticles (MPs) of Ganoderma lucidum polysaccharide (GLP). The prepared microparticles were characterized and evaluated. Prepared novel karaya gum micro-particles loaded Ganoderma lucidum polysaccharide (GLP MPs) were observed an effect on cadmium (CAD) induced testicular toxicity. A total of 40 rats (male) was divided into 4 groups viz. 1. Control group, 2. GLP MPs (250 mg/kg, 60 days of b.w per day), 3. CAD (60 days of 30 mg/l/day), 4. GLP MPs + CAD. CAD was responsible for altering the sex hormones, oxidative stress and inflammatory cytokines. Furthermore, elevated levels of indicator of oxidative stress, malondialdehyde, and a reduced action of SOD, GSH, and CAT (antioxidant enzymes), were observed in the tissues of the testicles of CAD- treated group. Such harmful occurrences were followed by an up-regulation in proinflammatory cytokines (TNF-α, IL-1β) levels, protein expression of Nrf2, and HO-1 expression was decreased. GLP MPs pre-treatment significantly abrogated these toxic effects which were confirmed histologically. This study concluded that pre-treatment with GLP MPs exerts a protective effect against CAD-induced male reproductive testicular toxicity.

Organophosphorus pesticides exhibit compound specific effects in rat precision-cut lung slices (PCLS): mechanisms involved in airway response, cytotoxicity, inflammatory activation and antioxidative defense

Organophosphorus compound pesticides (OP) are widely used in pest control and might be misused for terrorist attacks. Although acetylcholinesterase (AChE) inhibition is the predominant toxic mechanism, OP may induce pneumonia and formation of lung edema after poisoning and during clinical treatment as life-threatening complication. To investigate the underlying mechanisms, rat precision-cut lung slices (PCLS) were exposed to the OP parathion, malathion and their biotransformation products paraoxon and malaoxon (100–2000 µmol/L). Airway response, metabolic activity, release of LDH, cytokine expression and oxidative stress response were analyzed. A concentration-dependent inhibition of airway relaxation was observed after exposure with the oxon but not with the thion-OP. In contrast, cytotoxic effects were observed for both forms in higher concentrations. Increased cytokine expression was observed after exposure to parathion and paraoxon (IL-6, GM-CSF, MIP-1α) and IL-6 expression was dependent on NFκB activation. Intracellular GSH levels were significantly reduced by all four tested OP but an increase in GSSG and HO-1 expression was predominantly observed after malaoxon exposure. Pretreatment with the antioxidant N-acetylcysteine reduced malaoxon but not paraoxon-induced cytotoxicity. PCLS as a 3D lung model system revealed OP-induced effects depending on the particular OP. The experimental data of this study contribute to a better understanding of OP toxicity on cellular targets and may be a possible explanation for the variety of clinical outcomes induced by different OP.

Induction of Heme Oxygenase-1 Is Linked to the Severity of Disease in Human Abdominal Aortic Aneurysm

Background

Rupture of abdominal aortic aneurysm (rAAA) is associated with high case fatality rates, and risk of rupture increases with the AAA diameter. Heme oxygenase‐1 (gene HMOX1, protein HO‐1) is a stress‐induced protein and induction has protective effects in the vessel wall. HMOX1^−/− mice are more susceptible to angiotensin II‐induced AAA formation, but the regulation in human nonruptured and ruptured AAA is only poorly understood. Our hypothesis proposed that HO‐1 is reduced in AAA and lowering is inversely associated with the AAA diameter.

Methods and Results

AAA walls from patients undergoing elective open repair (eAAA) or surgery because of rupture (rAAA) were analyzed for aortic HMOX1/HO‐1 expression by quantitative real‐time polymerase chain reaction and Western blot. Aortas from patients with aortic occlusive disease served as controls. HMOX1/HO‐1 expression was 1.1‐ to 7.6‐fold upregulated in eAAA and rAAA. HO‐1 expression was 3‐fold higher in eAAA specimen with a diameter >84.4 mm, whereas HO‐1 was not different in rAAA. Other variables that are known for associations with AAA and HO‐1 induction were tested. In eAAA, HO‐1 expression was negatively correlated with aortic collagen content and oxidative stress parameters H₂O₂ release, oxidized proteins, and thiobarbituric acid reactive substances. Serum HO‐1 concentrations were analyzed in patients with eAAA, and maximum values were found in an aortic diameter of 55 to 70 mm with no further increase >70 mm, compared with <55 mm.

Conclusions

Aortic HO‐1 expression was increased in eAAA and rAAA. HO‐1 increased with the severity of disease but was additionally connected to less oxidative stress and vasoprotective mechanisms.

Tin Mesoporphyrin Selectively Reduces Non-Small-Cell Lung Cancer Cell Line A549 Proliferation by Interfering with Heme Oxygenase and Glutathione Systems

In order to maintain redox homeostasis, non-small-cell lung cancer (NSCLC) increases the activation of many antioxidant systems, including the heme-oxygenase (HO) system. The overexpression of HO-1 has been often associated with chemoresistance and tumor aggressiveness. Our results clearly showed an overexpression of the HO-1 protein in A549 NSCLC cell lines compared to that in non-cancerous cells. Thus, we hypothesized that "off-label" use of tin mesoporphyrin, a well-known HO activity inhibitor clinically used for neonatal hyperbilirubinemia, has potential use as an anti-cancer agent. The pharmacological inhibition of HO activity caused a reduction in cell proliferation and migration of A549. SnMP treatment caused an increase in oxidative stress, as demonstrated by the upregulation of reactive oxygen species (ROS) and the depletion of glutathione (GSH) content. To support these data, Western blot analysis was performed to analyze glucose-6-phosphate dehydrogenase (G6PD), TP53-induced glycolysis and the apoptosis regulator (TIGAR), and the glutamate cysteine ligase catalytic (GCLC) subunit, as they represent the main regulators of the pentose phosphate pathway (PPP) and glutathione synthesis, respectively. NCI-H292, a subtype of the NSCLC cell line, did not respond to SnMP treatment, possibly due to low basal levels of HO-1, suggesting a cellular-dependent antitumorigenic effect. Altogether, our results suggest HO activity inhibition may represent a potential target for selective chemotherapy in lung cancer subtypes.

Antidiabetic Agent DPP-4i Facilitates Murine Breast Cancer Metastasis by Oncogenic ROS-NRF2-HO-1 Axis via a Positive NRF2-HO-1 Feedback Loop

Cancer has been as one of common comorbidities of diabetes. Long-term antidiabetic treatment may potentially exert uncertain impacts on diabetic patients with cancer including breast cancer (BC). Dipeptidyl peptidase-4 inhibitors (DPP-4i) are currently recommended by the AACE as first-line hypoglycemic drugs in type 2 diabetes mellitus (T2DM). Although the safety of DPP-4i has been widely evaluated, the potential side-effects of DPP-4i in cancer metastasis were also reported and remain controversial. Here, we revealed that Saxagliptin (Sax) and Sitagliptin (Sit), two common DPP-4i compounds, potentially promoted murine BC 4T1 metastasis in vitro and in vivo under immune-deficient status. Mechanically, we observed that DPP-4i treatment induced aberrant oxidative stress by triggering ROS overproduction, as well as ROS-dependent NRF2 and HO-1 activations in BC cells, while specific inhibition of ROS, NRF2 or HO-1 activations abrogated DPP-4i-driven BC metastasis and metastasis-associated gene expression in vitro. Furthermore, ALA, a NRF2 activator significantly promoted BC metastasis in vitro and in vivo, which can be abrogated by specific HO-1 inhibition in vitro. Moreover, specific HO-1 inhibition not only reversed DPP-4i-induced NRF2 activation but also abrogated ALA-induced NRF2 activation, resulting in a decrease of metastasis-associated genes, indicating a positive-feedback NRF2-HO-1 loop. Our findings suggest that DPP-4i accelerates murine BC metastasis through an oncogenic ROS-NRF2-HO-1 axis via a positive-feedback NRF2-HO-1 loop. Therefore, this study not only offers novel insights into an oncogenic role of DPP-4i in BC progression but also provides new strategies to alleviate the dark side of DPP-4i by targeting HO-1.

Heme Oxygenase-1 in Patients With Interstitial Lung Disease: A Review of the Clinical Evidence

The clinical course and rate of progression of interstitial lung disease (ILD) are extremely variable among patients. For the purpose of monitoring disease activity, ILD diagnosis, and predicting disease prognosis, there are various biomarkers, including symptoms, physiological, radiological, and pathological findings, and peripheral blood and bronchoalveolar lavage fluid results. Of these, blood biomarkers such as sialylated carbohydrate antigen, surfactant proteins-A and -D, CC-chemokine ligand 18, matrix metalloprotease-1 and -7, CA19-9, and CA125 have been previously proposed. In the future, heme oxygenase-1 (HO-1) may also become a candidate ILD biomarker; it is a 32-kDa heat shock protein converting heme to carbon monoxide, biliverdin/bilirubin, and free iron to play a role in the pulmonary cytoprotective reaction in response to various stimuli. Recent research suggests that HO-1 can increase in lung tissues of patients with ILD, reflecting anti-inflammatory M2 macrophage activation, and the measurement of HO-1 levels in peripheral blood can be useful for evaluating the severity of lung damage in ILD and for predicting subsequent fibrosis formation.

Construction of Lycetin Nanocarriers and Its Effect on the Proliferation and Apoptosis of Hepatocellular Carcinoma Cells by Regulating Nuclear Factor E2 Related Factor/Antioxidant Response Element Pathway

This article explores the role of lysin nanocarriers in inducing apoptosis of human hepatocellular carcinoma cells and the possible molecular mechanisms. Cytotoxicity tests were performed in human fibroblast cell line MRC-5. Anti-cancer activity was tested in liver cancer cell lines HepG2 and HCCLM3. The results show that nanocarriers have a targeting effect on cancer cells, have high safety, and are good delivery vehicles for drugs. In this paper, the stability of lycopene and its degradation in aqueous solutions at different temperatures were studied, and the structure and mechanism of degradation products were determined. A new type of mesoporous silica nanocarrier was synthesized as a delivery carrier of lysin and its derivatives, which has a targeting effect on cancer cells and has a slow-release effect. Surface modification can improve circulation time and stability for future resistance in vivo. The cancer experiment laid the foundation. The results showed that the lysin nanocarriers inhibited the proliferation of HepG2 and HCCLM3 human liver cancer cells in a dependent manner. After the lysin nanocarriers acted on HepG2 human hepatocellular carcinoma cells for 48 h, the cell apoptosis rate was significantly increased by flow cytometry analysis. The carrier can significantly increase the levels of reactive oxygen species and malondialdehyde, and reduce the content of reduced glutathione and superoxide dismutase. At the same time, the lysin nanocarrier can down-regulate the expression of Nrf2 and HO-1 proteins, and inhibit the occurrence of Nrf2 Nuclear displacement. The lycopene nanocarrier inhibits the proliferation of HepG2, HCCLM3 human liver cancer cells, induces apoptosis, regulates the oxidative stress response in the cell, and regulates the Nrf2/AREE antioxidant signaling pathway, thereby promoting tumor cell apoptosis.

Mitochondrial GRIM-19 deficiency facilitates gastric cancer metastasis through oncogenic ROS-NRF2-HO-1 axis via a NRF2-HO-1 loop

BACKGROUND

NRF2, a prime target of cellular defense against oxidative stress, has shown a dark side profile in cancer progression. GRIM-19, an essential subunit of the mitochondrial MRC complex I, was recently identified as a suppressive role in tumorigenesis of human gastric cancer (GC). However, little information is available on the role of GRIM-19 and its cross-talk with NRF2 in GC metastasis.

METHODS

Online GC database was used to investigate DNA methylation and survival outcomes of GRIM-19. CRISPR/Cas9 lentivirus-mediated gene editing, metastasis mice models and pharmacological intervention were applied to investigate the role of GRIM-19 deficiency in GC metastasis. Quantitative RT-PCR, FACS, Western blot, IHC, IF and reporter gene assay were performed to explore underlying mechanisms.

RESULTS

Low GRIM-19 is correlated with poor survival outcome of GC patients while DNA hypermethylation is associated with GRIM-19 downregulation. GRIM-19 deficiency facilitates GC metastasis and triggers aberrant oxidative stress as well as ROS-dependent NRF2-HO-1 activation. Experimental interventions of specific ROS, NRF2 or HO-1 inhibitor significantly abrogate GRIM-19 deficiency-driven GC metastasis in vitro and in vivo. Moreover, HO-1 inhibition not only reverses GRIM-19 deficiency-driven NRF2 activation, but also feedback blocks NRF2 activator-induced NRF2 signaling, resulting in decreased metastasis-associated genes.

CONCLUSIONS

Our data suggest that GRIM-19 deficiency accelerates GC metastasis through the oncogenic ROS-NRF2-HO-1 axis via a positive-feedback NRF2-HO-1 loop. Therefore, this study not only offers novel insights into the role of oncogenic NRF2 in tumor progression, but also provides new strategies to alleviate the dark side of NRF2 by targeting HO-1.

Redox Potential of Antioxidants in Cancer Progression and Prevention

The benevolent and detrimental effects of antioxidants are much debated in clinical trials and cancer research. Several antioxidant enzymes and molecules are overexpressed in oxidative stress conditions that can damage cellular proteins, lipids, and DNA. Natural antioxidants remove excess free radical intermediates by reducing hydrogen donors or quenching singlet oxygen and delaying oxidative reactions in actively growing cancer cells. These reducing agents have the potential to hinder cancer progression only when administered at the right proportions along with chemo-/radiotherapies. Antioxidants and enzymes affect signal transduction and energy metabolism pathways for the maintenance of cellular redox status. A decline in antioxidant capacity arising from genetic mutations may increase the mitochondrial flux of free radicals resulting in misfiring of cellular signalling pathways. Often, a metabolic reprogramming arising from these mutations in metabolic enzymes leads to the overproduction of so called ’oncometabolites’ in a state of ‘pseudohypoxia’. This can inactivate several of the intracellular molecules involved in epigenetic and redox regulations, thereby increasing oxidative stress giving rise to growth advantages for cancerous cells. Undeniably, these are cell-type and Reactive Oxygen Species (ROS) specific, which is manifested as changes in the enzyme activation, differences in gene expression, cellular functions as well as cell death mechanisms. Photodynamic therapy (PDT) using light-activated photosensitizing molecules that can regulate cellular redox balance in accordance with the changes in endogenous ROS production is a solution for many of these challenges in cancer therapy.

Chemo-preventive effect of crocin against experimentally-induced hepatocarcinogenesis via regulation of apoptotic and Nrf2 signaling pathways

The results of the current study investigated the chemo-preventive effect of crocin against hepatocarcinogenesis in rats with particular focus on the evaluation of the modulatory impact of crocin on apoptotic and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways. Thioacetamide (TAA) (200 mg/kg, I.P.) was used for experimental induction of hepatocarcinogenesis in rats. Crocin administration significantly attenuated TAA-induced cancerous lesions with concomitant attenuation of impaired liver functions. This was associated with significant enhancement in hepatic Nrf2 and heme oxygenase-1 (HO-1) expression with parallel suppression in Keap-1 expression. Inline, crocin induced a significant improvement in hepatic oxidative status with enhanced antioxidant batteries. Crocin administration significantly suppressed the hepatic content of c-Jun N-terminal kinase (c-JNK) with significant upregulation in TNF-related apoptosis-inducing ligand (TRAIL) and caspase-8 protein expression as well as p53 gene expression; biomarkers of apoptosis. Moreover, hepatic expression of the apoptotic BAX significantly increased and the anti-apoptotic Bcl-2 significantly decreased in the liver specimen; biomarkers of intrinsic apoptosis. In conclusion; crocin attenuates experimentally induced hepato-carcinogenesis via modulation of oxidative/apoptotic signaling. Namely, crocin induced hepatic expression of Nrf2 with downstream modulation of endogenous HO-1 and Keap-1 signaling with modulation of various key players of apoptosis including; c-JNK, p53, TRAIL, caspase-8, BAX, and Bcl-2.

Progressive Lung Injury, Inflammation, and Fibrosis in Rats Following Inhalation of Sulfur Mustard

Sulfur mustard (SM) inhalation causes debilitating pulmonary injury in humans which progresses to fibrosis. Herein, we developed a rat model of SM toxicity which parallels pathological changes in the respiratory tract observed in humans. SM vapor inhalation caused dose (0.2-0.6 mg/kg)-related damage to the respiratory tract within 3 days of exposure. At 0.4-0.6 mg/kg, ulceration of the proximal bronchioles, edema and inflammation were observed, along with a proteinaceous exudate containing inflammatory cells in alveolar regions. Time course studies revealed that the pathologic response was biphasic. Thus, changes observed at 3 days post-SM were reduced at 7-16 days; this was followed by more robust aberrations at 28 days, including epithelial necrosis and hyperplasia in the distal bronchioles, thickened alveolar walls, enlarged vacuolated macrophages, and interstitial fibrosis. Histopathologic changes were correlated with biphasic increases in bronchoalveolar lavage (BAL) cell and protein content and proliferating cell nuclear antigen expression. Proinflammatory proteins receptor for advanced glycation end product (RAGE), high-mobility group box protein (HMGB)-1, and matrix metalloproteinase (MMP)-9 also increased in a biphasic manner following SM inhalation, along with surfactant protein-D (SP-D). Tumor necrosis factor (TNF)-α and inducible nitric oxide synthase (iNOS), inflammatory proteins implicated in mustard lung toxicity, and the proinflammatory/profibrotic protein, galectin (Gal)-3, were upregulated in alveolar macrophages and in bronchiolar regions at 3 and 28 days post-SM. Inflammatory changes in the lung were associated with oxidative stress, as reflected by increased expression of heme oxygenase (HO)-1. These data demonstrate a similar pathologic response to inhaled SM in rats and humans suggesting that this rodent model can be used for mechanistic studies and for the identification of efficacious therapeutics for mitigating toxicity.

Combined Treatment with Low Cytotoxic Ethyl Acetate Nepenthes Extract and Ultraviolet-C Improves Antiproliferation to Oral Cancer Cells via Oxidative Stress

Ultraviolet-C (UVC) irradiation provides an alternative radiotherapy to X-ray. UVC sensitizer from natural products may improve radiotherapy at low cytotoxic side effects. The aim of this study is to assess the regulation for oral cancer cell proliferation by a combined treatment of UVC and our previously reported anti-oral cancer natural product (ethyl acetate extract of Nepenthes adrianii × clipeata; EANA). The detailed possible UVC sensitizing mechanisms of EANA such as effects on cell proliferation, cell cycle, apoptosis, and DNA damage are investigated individually and in combination using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTS) assay, flow cytometry, and western blotting at low dose conditions. In a 24 h MTS assay, the low dose EANA (5 μg/mL) and low dose UVC (12 J/m²) individually show 80% and combinedly 57% cell proliferation in oral cancer Ca9-22 cells; but no cytotoxicity to normal oral HGF-1 cells. Mechanistically, low dose EANA and low dose UVC individually induce apoptosis (subG1 accumulation, pancaspase activation, and caspases 3, 8, 9), oxidative stress (reactive oxygen species, mitochondrial superoxide, and mitochondrial membrane potential depletion), and DNA damage (γH2AX and 8-hydroxy-2′-deoxyguanosine). Moreover, the combined treatment (UVC/EANA) synergistically induces these changes. Combined low dose treatment-induced antiproliferation, apoptosis, oxidative stress, and DNA damage were suppressed by the ROS scavenger N-acetylcysteine. In conclusion, UVC/EANA shows synergistic antiproliferation, oxidative stress, apoptosis, and DNA damage to oral cancer cells in an oxidative stress-dependent manner. With the selective killing properties of low dose EANA and low dose UVC, EANA provides a novel UVC sensitizing agent to improve the anti-oral cancer therapy.

N-acetylcysteine Provides Cytoprotection in Murine Oligodendrocytes through Heme Oxygenase-1 Activity

Oligodendrocytic injury by oxidative stress can lead to demyelination, contributing to neurodegeneration. We investigated the mechanisms by which an antioxidant, N-acetylcysteine (NAC), reduces oxidative stress in murine oligodendrocytes. We used normal 158N and mutant 158JP cells with endogenously high reactive oxygen species (ROS) levels. Oxidative stress was induced in 158N cells using hydrogen peroxide (H₂O₂, 500 μM), and both cells were treated with NAC (50 µM to 500 µM). ROS production, total glutathione (GSH) and cell survival were measured 24 h after treatment. In normal cells, H₂O₂ treatment resulted in a ~5.5-fold increase in ROS and ~50% cell death. These deleterious effects of oxidative stress were attenuated by NAC, resulting in improved cell survival. Similarly, NAC treatment resulted in decreased ROS levels in 158JP cells. Characterization of mechanisms underlying cytoprotection in both cell lines revealed an increase in GSH levels by NAC, which was partially blocked by an inhibitor of GSH synthesis. Interestingly, we observed heme oxygenase-1 (HO-1), a cytoprotective enzyme, play a critical role in cytoprotection. Inhibition of HO-1 activity abolished the cytoprotective effect of NAC with a corresponding decrease in total antioxidant capacity. Our results indicate that NAC promotes oligodendrocyte survival in oxidative stress-related conditions through multiple pathways.

Impact of Endocytosis and Lysosomal Acidification on the Toxicity of Copper Oxide Nano- and Microsized Particles: Uptake and Gene Expression Related to Oxidative Stress and the DNA Damage Response

The toxicity of the copper oxide nanoparticles (CuO NP) has been attributed to the so-called "Trojan horse"-type mechanism, relying on the particle uptake and extensive intracellular release of copper ions, due to acidic pH in the lysosomes. Nevertheless, a clear distinction between extra- and intracellular-mediated effects is still missing. Therefore, the impact of the endocytosis inhibitor hydroxy-dynasore (OH-dyn), as well as bafilomycin A1 (bafA1), inhibiting the vacuolar type H⁺-ATPase (V-ATPase), on the cellular toxicity of nano- and microsized CuO particles, was investigated in BEAS 2 B cells. Selected endpoints were cytotoxicity, copper uptake, glutathione (GSH) levels, and the transcriptional DNA damage and (oxidative) stress response using the high-throughput reverse transcription quantitative polymerase chain reaction (RT-qPCR). OH-dyn markedly reduced intracellular copper accumulation in the cases of CuO NP and CuO MP; the modulation of gene expression, induced by both particle types affecting especially HMOX1, HSPA1A, MT1X, SCL30A1, IL8 and GADD45A, were completely abolished. BafA1 lowered the intracellular copper concentration in case of CuO NP and strongly reduced transcriptional changes, while any CuO MP-mediated effects were not affected by bafA1. In conclusion, the toxicity of CuO NP depended almost exclusively upon dynamin-dependent endocytosis and the intracellular release of redox-active copper ions due to lysosomal acidification, while particle interactions with cellular membranes appeared to be not relevant.

Toxic consequences and oxidative protein carbonylation from chloropicrin exposure in human corneal epithelial cells

Chloropicrin (CP), a warfare agent now majorly used as a soil pesticide, is a strong irritating and lacrimating compound with devastating toxic effects. To elucidate the mechanism of its ocular toxicity, toxic effects of CP (0-100 μM) were studied in primary human corneal epithelial (HCE) cells. CP exposure resulted in reduced HCE cell viability and increased apoptotic cell death with an up-regulation of cleaved caspase-3 and poly ADP ribose polymerase indicating their contribution in CP-induced apoptotic cell death. Following CP exposure, cells exhibited increased expression of heme oxygenase-1, and phosphorylation of H2A.X and p53 as well as 4-hydroxynonenal adduct formation, suggesting oxidative stress, DNA damage and lipid peroxidation. CP also caused increases in mitogen activated protein kinase-c-Jun N-terminal kinase and inflammatory mediator cyclooxygenase-2. Proteomic analysis revealed an increase in the carbonylation of 179 proteins and enrichment of pathways (including proteasome pathway and catabolic process) in HCE cells following CP exposure. CP-induced oxidative stress and lipid peroxidation can enhance protein carbonylation, prompting alterations in corneal epithelial proteins as well as perturbing signaling pathways resulting in toxic effects. Pathways and major processes identified following CP exposure could be lead-hit targets for further biochemical and molecular characterization as well as therapeutic intervention.

Grass carp (Ctenopharyngodon idella) NRF2 alleviates the oxidative stress and enhances cell viability through upregulating the expression of HO-1

As a member of the Cap 'n' Collar (CNC) family, NRF2 contains a basic leucine zipper (bZip) and can regulate the downstream target gene heme oxygenase 1 (HO-1) in response to oxidative stress. In the present study, a grass carp (Ctenopharyngodon idella) NRF2 ORF was cloned and identified. The largest ORF (1782 bp) encodes a polypeptide of 593 amino acids. The deduced amino acid sequence of grass carp NRF2 (CiNRF2) contains a well-conserved DNA-binding domain (BRLZ domain). Phylogenetic tree analysis revealed that CiNRF2 has a closer evolutionary relationship with other fish counterparts. After CIK (C. idellus kidney) cells were persistently stimulated with tunicamycin (TM), CiNRF2 was significantly upregulated from 12 to 36 h. Then, the expression was dropped at 48 h post-infection. Additionally, when TM or TG (thapsigargin) stimulated CIK cells, overexpression of CiNRF2 in cells downregulated the expression of Bip mRNA, a marker protein of oxidative stress, suggesting that fish NRF2 can alleviate the oxidative stress level induced by TM or TG. To study the protective mechanism of fish NRF2, the DNA sequences of CiNRF2 and CiATF4 (grass carp ATF4) were separately sub-cloned into the expression vectors pEGFP and pCMV-Flag for co-immunoprecipitation and GST pull-down assays. These assays showed that CiNRF2 can combine with CiATF4 through its Neh1 domain. Meanwhile, we cloned grass carp HO-1 promoter sequence and constructed the recombinant plasmid of pGL3-HO-1. Soon afterwards, pGL3-HO-1 was co-transfected into grass carp ovary (CO) cells with pcDNA3.1-CiNRF2 or pcDNA3.1-CiATF4, respectively. The results showed that the luciferase activity of pGL3-HO-1 in the overexpressed CiNRF2 plus CiATF4 cells was significantly increased, along with the increase of cell viability (~ 133%). However, when HO-1 was knocked down in cells, CiNRF2 was unable to perform its function. These results demonstrated that CiNRF2 was effective in protecting grass carp against the oxidative stress induced by TM and increasing cell viability by upregulating HO-1 expression.

Fabrication of capsaicin emulsions: improving the stability of the system and relieving the irritation to the gastrointestinal tract of rats

BACKGROUND

Capsaicin, as a major pungent ingredient of peppers, has many health benefits. However, the strong irritation effect of capsaicin inhibits its application in the food industry. Emulsions can be an effective approach to alleviate the irritation.

RESULTS

In this study, we used tocopheryl polyethylene glycol 1000 succinate (TPGS) as an emulsifier to prepare capsaicin emulsions through high-pressure homogenization. Capsaicin emulsions with a particle size of about 100 nm, -36.4 mV zeta potential, and 91.9% encapsulation efficiency were prepared successfully and showed better environmental stability and higher antioxidant activity. Emulsions reduced the cumulative release of capsaicin and had no toxic effect on buffalo rat liver (BRL-3A) cells. Moreover, the gastrointestinal injury model of rats showed that emulsions reduced the strong irritation of capsaicin.

CONCLUSION

This work provides a theoretical basis for the application of irritant ingredients in food industry. © 2019 Society of Chemical Industry.

SerpinB3 Differently Up-Regulates Hypoxia Inducible Factors -1α and -2α in Hepatocellular Carcinoma: Mechanisms Revealing Novel Potential Therapeutic Targets

Background: SerpinB3 (SB3) is a hypoxia and hypoxia-inducible factor (HIF)-2α-dependent cysteine-protease inhibitor up-regulated in hepatocellular carcinoma (HCC), released by cancer cells and able to stimulate proliferation and epithelial-to-mesenchymal-transition. Methods: In the study we employed transgenic and knock out SerpinB3 mice, liver cancer cell line, human HCC specimens, and mice receiving diethyl-nitrosamine (DEN) administration plus choline-deficient L-amino acid refined (CDAA) diet (DEN/CDAA protocol). Results: We provide detailed and mechanistic evidence that SB3 can act as a paracrine mediator able to affect the behavior of surrounding cells by differentially up-regulating, in normoxic conditions, HIF-1α and HIF-2α. SB3 acts by (i) up-regulating HIF-1α transcription, facilitating cell survival in a harsh microenvironment and promoting angiogenesis, (ii) increasing HIF-2α stabilization via direct/selective NEDDylation, promoting proliferation of liver cancer cells, and favoring HCC progression. Moreover (iii) the highest levels of NEDD8-E1 activating enzyme (NAE1) mRNA were detected in a subclass of HCC patients expressing the highest levels of HIF-2α transcripts; (iv) mice undergoing DEN/CDAA carcinogenic protocol showed a positive correlation between SB3 and HIF-2α transcripts with the highest levels of NAE1 mRNA detected in nodules expressing the highest levels of HIF-2α transcripts. Conclusions: These data outline either HIF-2α and NEDDylation as two novel putative therapeutic targets to interfere with the procarcinogenic role of SerpinB3 in the development of HCC.

MhuD from Mycobacterium tuberculosis: Probing a Dual Role in Heme Storage and Degradation

The Mycobacterium tuberculosis (Mtb) heme oxygenase MhuD liberates free iron by degrading heme to the linear tetrapyrrole mycobilin. The MhuD dimer binds up to two hemes within the active site of each monomer. Binding the first solvent-exposed heme allows heme degradation and releases free iron. Binding a second heme renders MhuD inactive, allowing heme storage. Native-mass spectrometry revealed little difference in binding affinity between solvent-exposed and solvent-protected hemes. Hence, diheme-MhuD is formed even when a large proportion of the MhuD population is in the apo form. Apomyoglobin heme transfer assays showed MhuD-diheme dissociation is far slower than monoheme dissociation at ∼0.12 min^-1 and ∼0.25 s^-1, respectively, indicating that MhuD has a strong affinity for diheme. MhuD has not evolved to preferentially occupy the monoheme form and, through formation of a diheme complex, it functions as part of a larger network to tightly regulate both heme and iron levels in Mtb.

Parthenolide inhibits lipid accumulation via activation of Nrf2/Keap1 signaling during adipocyte differentiation

The effects of parthenolide (PL), a sesquiterpene lactone obtained from feverfew plant, on lipid accumulation and signaling pathway in adipocytes were investigated. PL significantly inhibited lipid accumulation and adipogenic factors during adipogenesis. In particular, PL exerted its inhibitory effects in early adipogenic stage by regulating the early adipogenic factors. In addition, PL regulated the expression of adipokines; leptin, retinol binding protein, and resistin mRNAs were downregulated, whereas adiponectin gene expression was increased. Furthermore, PL significantly reduced intracellular reactive oxygen species (ROS) production during adipogenesis. This PL-mediated regulation of ROS production was associated with the regulation of nuclear factor erythroid 2-related factor (Nrf2)-kelch-like ECH-associated protein 1 (Keap1) pathway. PL effectively increased the abundance of Nrf2 and its target proteins, heme oxygenase-1 (HO-1) and NADPH dehydrogenase 1 (NQO1), by promoting the nuclear translocation of Nrf2, indicating that PL-mediated anti-adipogenic effects are associated with the Nrf2/Keap1 pathway.

Heme Oxygenase 1 Induces Tau Oligomer Formation and Synapse Aberrations in Hippocampal Neurons

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by behavioral changes and cognitive decline. Recent evidence suggests that it is the soluble forms of tau oligomers (Tau-O) and Aβ oligomers (oAβ) rather than the well-studied insoluble protein aggregates that possess the neurotoxicity, infectivity, and amplification underlying disease progression. Heme oxygenase 1 (HO-1), an inducible enzyme upregulated in the cortex and hippocampus of AD brains, was reported to damage neural structures and disrupt brain function, suggesting possible contributions to Tau-O-mediated neurodegeneration. In this study, we focused on the effects of HO-1 on Tau-O formation. In hippocampus of HO-1-overexpressing transgenic mice and neural 2a (N2a) cells, Tau-O was co-localized with HO-1 as visualized by immunofluorescence staining. Furthermore, primary cultured hippocampal neurons from HO-1 transgenic mice showed elevated Tau-O and concomitant reductions in spine density and length as well as dendritic length, diameter, and arborization. Blocking Tau-O formation by isoprenaline reversed these HO-1-induced morphological changes. These results indicated that HO-1 contributes to Tau-O formation and ensuing synaptic damage. Thus, HO-1 is a promising target for AD drug development.

Nrf2 as a Potential Mediator of Cardiovascular Risk in Metabolic Diseases

Free radicals act as secondary messengers, modulating a number of important biological processes, including gene expression, ion mobilization in transport systems, protein interactions and enzymatic functions, cell growth, cell cycle, redox homeostasis, among others. In the cardiovascular system, the physiological generation of free radicals ensures the integrity and function of cardiomyocytes, endothelial cells, and adjacent smooth muscle cells. In physiological conditions, there is a balance between free radicals generation and the activity of enzymatic and non-enzymatic antioxidant systems. Redox imbalance, caused by increased free radical's production and/or reduced antioxidant defense, plays an important role in the development of cardiovascular diseases, contributing to cardiac hypertrophy and heart failure, endothelial dysfunction, hypertrophy and hypercontractility of vascular smooth muscle. Excessive production of oxidizing agents in detriment of antioxidant defenses in the cardiovascular system has been described in obesity, diabetes mellitus, hypertension, and atherosclerosis. The transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2), a major regulator of antioxidant and cellular protective genes, is primarily activated in response to oxidative stress. Under physiological conditions, Nrf2 is constitutively expressed in the cytoplasm of cells and is usually associated with Keap-1, a repressor protein. This association maintains low levels of free Nrf2. Stressors, such as free radicals, favor the translocation of Nrf2 to the cell nucleus. The accumulation of nuclear Nrf2 allows the binding of this protein to the antioxidant response element of genes that code antioxidant proteins. Although little information on the role of Nrf2 in the cardiovascular system is available, growing evidence indicates that decreased Nrf2 activity contributes to oxidative stress, favoring the pathophysiology of cardiovascular disorders found in obesity, diabetes mellitus, and atherosclerosis. The present mini-review will provide a comprehensive overview of the role of Nrf2 as a contributing factor to cardiovascular risk in metabolic diseases.

Specificity of the Metallothionein-1 Response by Cadmium-Exposed Normal Human Urothelial Cells

Occupational and environmental exposure to cadmium is associated with the development of urothelial cancer. The metallothionein (MT) family of genes encodes proteins that sequester metal ions and modulate physiological processes, including zinc homeostasis. Little is known about the selectivity of expression of the different MT isoforms. Here, we examined the effect of cadmium exposure on MT gene and isoform expression by normal human urothelial (NHU) cell cultures. Baseline and cadmium-induced MT gene expression was characterized by next-generation sequencing and RT-PCR; protein expression was assessed by Western blotting using isoform-specific antibodies. Expression of the zinc transporter-1 (SLC30A1) gene was also assessed. NHU cells displayed transcription of MT-2A, but neither MT-3 nor MT-4 genes. Most striking was a highly inducer-specific expression of MT-1 genes, with cadmium inducing transcription of MT-1A, MT-1G, MT-1H, and MT-1M. Whereas MT-1G was also induced by zinc and nickel ions and MT-1H by iron, both MT-1A and MT-1M were highly cadmium-specific, which was confirmed for protein using isoform-specific antibodies. Protein but not transcript endured post-exposure, probably reflecting sequestration. SLC30A1 transcription was also affected by cadmium ion exposure, potentially reflecting perturbation of intracellular zinc homeostasis. We conclude that human urothelium displays a highly inductive profile of MT-1 gene expression, with two isoforms identified as highly specific to cadmium, providing candidate transcript and long-lived protein biomarkers of cadmium exposure.

Genistein Prevents Development of Spontaneous Ovarian Cancer and Inhibits Tumor Growth in Hen Model

Genistein, the major isoflavone in soybean, has been reported to exert anticancer effects on various types of cancer including ovarian cancer; however, its chemopreventive effects and mechanisms of action in ovarian cancer have not been fully elucidated in spontaneously developing ovarian cancer models. In this study, we demonstrated the preventive effects and mechanisms of genistein in the laying hen model that develops spontaneous ovarian cancer at high incidence rates. Laying hens were randomized to three groups: control (3.01 mg/hen, n = 100), low (52.48 mg/hen n = 100), and high genistein supplementation (106.26 mg/hen/day; per group). At the end of 78 weeks, hens were euthanized and ovarian tumors were collected and analyzed. We observed that genistein supplementation significantly reduced the ovarian tumor incidence (P = 0.002), as well as the number and size of the tumors (P = 0.0001). Molecular analysis of the ovarian tumors revealed that genistein downregulated serum malondialdehyde, a marker for oxidative stress and the expression of NFκB and Bcl-2, whereas it upregulated Nrf2, HO-1, and Bax expression at protein level in ovarian tissues. Moreover, genistein intake decreased the activity of mTOR pathway as evidenced by reduced phosphorylation of mTOR, p70S6K1, and 4E-BP1. Taken together, our findings strongly support the potential of genistein in the chemoprevention of ovarian cancer and highlight the effects of the genistein on the molecular pathways involved in ovarian tumorigenesis.