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Acute myeloid leukemia (AML) is a molecularly heterogenous hematological malignancy, with one of the most common mutations being internal tandem duplication (ITD) of the juxtamembrane domain of the fms-like tyrosine kinase receptor-3 (FLT3). Despite the development of FLT3-directed tyrosine kinase inhibitors (TKI), relapse and resistance are problematic, requiring improved strategies. In both patient samples and cell lines, FLT3-ITD raises levels of reactive oxygen species (ROS) and elicits an antioxidant response which is linked to chemoresistance broadly in AML. NF-E2–related factor 2 (NRF2) is a transcription factor regulating the antioxidant response including heme oxygenase -1 (HO-1), a heat shock protein implicated in AML resistance. Here, we demonstrate that HO-1 is elevated in FLT3-ITD-bearing cells compared to FLT3-wild type (WT). Transient knockdown or inhibitor-based suppression of HO-1 enhances vulnerability to the TKI, quizartinib, in both TKI-resistant and sensitive primary AML and cell line models. NRF2 suppression (genetically or pharmacologically using brusatol) results in decreased HO-1, suggesting that TKI-resistance is dependent on an active NRF2-driven pathway. In AML-patient derived xenograft (PDX) models, brusatol, in combination with daunorubicin, reduces leukemia burden and prolongs survival. Cumulatively, these data encourage further development of brusatol and NRF2 inhibition as components of combination therapy for refractory AML. [ABSTRACT FROM AUTHOR]

Neuromuscular electrical stimulation (NMES) allows activation of muscle fibers in the absence of voluntary force generation. NMES could have the potential to promote muscle homeostasis in the context of muscle disease, but the impacts of NMES on diseased muscle are not well understood. We used the zebrafish Duchenne muscular dystrophy (dmd) mutant and a longitudinal design to elucidate the consequences of NMES on muscle health. We designed four neuromuscular stimulation paradigms loosely based on weightlifting regimens. Each paradigm differentially affected neuromuscular structure, function, and survival. Only endurance neuromuscular stimulation (eNMES) improved all outcome measures. We found that eNMES improves muscle and neuromuscular junction morphology, swimming, and survival. Heme oxygenase and integrin alpha7 are required for eNMES-mediated improvement. Our data indicate that neuromuscular stimulation can be beneficial, suggesting that the right type of activity may benefit patients with muscle disease. [ABSTRACT FROM AUTHOR]

Plant growth under abiotic stress conditions significantly enhances intracellular generation of reactive oxygen species (ROS). Oxidative status of plant cells is directly affected by the modulation of iron homeostasis. Among mammals and plants, heme oxygenase-1 (HO-1) is a well-known antioxidant enzyme. It catalyzes oxygenation of heme, thereby producing Fe2+, CO and biliverdin as byproducts. The antioxidant potential of HO-1 is primarily due to its catalytic reaction byproducts. Biliverdin and bilirubin possess conjugated π-electrons which escalate the ability of these biomolecules to scavenge free radicals. CO also enhances the ROS scavenging ability of plants cells by upregulating catalase and peroxidase activity. Enhanced expression of HO-1 in plants under oxidative stress accompanies sequestration of iron in specialized iron storage proteins localized in plastids and mitochondria, namely ferritin for Fe3+ storage and frataxin for storage of Fe–S clusters, respectively. Nitric oxide (NO) crosstalks with HO-1 at multiple levels, more so in plants under oxidative stress, in order to maintain intracellular iron status. Formation of dinitrosyl-iron complexes (DNICs) significantly prevents Fenton reaction during oxidative stress. DNICs also release NO upon dissociation in target cells over long distance in plants. They also function as antioxidants against superoxide anions and lipidic free radicals. A number of NO-modulated transcription factors also facilitate iron homeostasis in plant cells. Plants facing oxidative stress exhibit modulation of lateral root formation by HO-1 through NO and auxin-dependent pathways. The present review provides an in-depth analysis of the structure-function relationship of HO-1 in plants and mammals, correlating them with their adaptive mechanisms of survival under stress. [Display omitted] • Oxidative stress in plants is downregulated by Fe, CO and biliverdin produced by the action of heme oxygenase-1 (HO-1). • HO-1-NO crosstalk regulates iron homeostasis under abiotic stress conditions. • Storage of iron and Fe–S cluster in ferritin and frataxin, respectively, is modulated by HO-1 and NO. • HO-1 in plants and mammals exhibit functional similarities in the modulation of their activity by NO. • Dinitrosyl-iron complexes (DNICs) play crucial role as antioxidants and NO donor. [ABSTRACT FROM AUTHOR]

The rich source of heme within malarial parasites has been considered to underly the action specificity of artemisinin. We reasoned that increasing intraparasitic free heme levels might further sensitize the parasites to artemisinin. Various means, such as modulating heme synthesis, degradation, polymerization, or hemoglobin digestion, were tried to boost intracellular heme levels, and under several scenarios, free heme levels were significantly augmented. Interestingly, all results arrived at the same conclusion, i.e., elevating heme acted in a strongly negative way, impacting the antimalarial action of artemisinin, but exerted no effect on several other antimalarial drugs. Suppression of the elevated free heme level by introducing heme oxygenase expression effectively restored artemisinin potency. Consistently, zinc protoporphyrin IX/zinc mesoporphyrin, as analogues of heme, drastically increased free heme levels and, concomitantly, the EC50 values of artemisinin. We were unable to effectively mitigate free heme levels, possibly due to an unknown compensating heme uptake pathway, as evidenced by our observation of efficient uptake of a fluorescent heme homologue by the parasite. Our results thus indicate the existence of an effective and mutually compensating heme homeostasis network in the parasites, including an uncharacterized heme uptake pathway, to maintain a certain level of free heme and that augmentation of the free heme level negatively impacts the antimalarial action of artemisinin. Importance: It is commonly believed that heme is critical in activating the antimalarial action of artemisinins. In this work, we show that elevating free heme levels in the malarial parasites surprisingly negatively impacts the action of artemisinin. We tried to boost free heme levels with various means, such as by modulating heme synthesis, heme polymerization, hemoglobin degradation and using heme analogues. Whenever we saw elevation of free heme levels, reduction in artemisinin potency was also observed. The homeostasis of heme appears to be complex, as there exists an unidentified heme uptake pathway in the parasites, nullifying our attempts to effectively reduce intraparasitic free heme levels. Our results thus indicate that too much heme is not good for the antimalarial action of artemisinins. This research can help us better understand the biological properties of this mysterious drug. [ABSTRACT FROM AUTHOR]

Cryptotanshinone (CTS) is a lipophilic constituent of Salvia miltiorrhiza , with a broad-spectrum anticancer activity. We have observed that CTS enhances the efficacy of gefitinib in human lung cancer H1975 cells, yet little is known about its molecular mechanism. To explore how CTS enhances H1975 cell sensitivity to gefitinib, we figured out differential proteins of H1975 cells treated by gefitinib alone or in combination with CTS using label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) bioinformatic analyses of the differential proteins were performed. CTS enhanced H1975 cell sensitivity to gefitinib in vitro and in vivo , with 115 and 128 differential proteins identified, respectively. GO enrichment, KEGG analysis, and PPI network comprehensively demonstrated that CTS mainly impacted the redox process and fatty acid metabolism in H1975 cells. Moreover, three differential proteins, namely, catalase (CAT), heme oxygenase 1 (HMOX1), and stearoyl-CoA desaturase (SCD) were validated by RT-qPCR and Western blot. In conclusion, we used a proteomic method to study the mechanism of CTS enhancing gefitinib sensitivity in H1975 cells. Our finding reveals the potential protein targets of CTS in overcoming gefitinib resistance, which may be therapeutical targets in lung cancer. [ABSTRACT FROM AUTHOR]

Background: Many women enter pregnancy with iron stores that are insufficient to maintain maternal iron balance and support fetal development and consequently, often require iron supplements. However, the side effects associated with many currently available iron supplements can limit compliance.Objective: This study aimed to test the safety and efficacy of a novel nanoparticulate iron supplement, a dietary ferritin analog termed iron hydroxide adipate tartrate (IHAT), in pregnant mice.Methods: Female C57BL/6 mice were maintained on either an iron-deficient or a control diet for 2 wk prior to timed mating to develop iron-deficient or iron-sufficient pregnancy models, respectively. Mice from each model were then gavaged daily with 10 mg iron/kg body weight as either IHAT or ferrous sulfate, or with water only, beginning on embryonic day (E) 4.5. Mice were killed on E18.5 and maternal iron and hematological parameters were measured. The expression of genes encoding iron transporters and oxidative stress markers in the duodenum and placenta were determined, along with hepatic expression of the gene encoding the iron regulatory hormone hepcidin and fetal iron.Results: Oral IHAT and ferrous sulfate were equally effective at increasing maternal hemoglobin (20.2% and 16.9%, respectively) and hepatic iron (30.2% and 29.3%, respectively), as well as total fetal iron (99.7% and 83.8%, respectively), in iron-deficient pregnant mice compared with those gavaged with water only, with no change in oxidative stress markers seen with either treatment. However, there was a significant increase in the placental expression of the oxidative stress marker heme oxygenase 1 in iron-replete pregnant mice treated with ferrous sulfate when compared with iron-replete pregnant mice gavaged with IHAT (96.9%, P <0.05).Conclusions: IHAT has proved a safe and effective alternative to oral ferrous sulfate in mice, and it has potential for treating iron deficiency in human pregnancy. [ABSTRACT FROM AUTHOR]

Intrauterine programming of cardiovascular and renal function occurs in diabetes because of the adverse maternal environment. Heme oxygenase 1 (HO-1) and -2 (HO-2) exert vasodilatory and antioxidant actions, particularly in conditions of elevated HO-1 expression or deficient nitric oxide levels. We evaluated whether the activity of the heme-HO system is differentially regulated by oxidative stress in the female offspring of diabetic mothers, contributing to the improved cardiovascular function in comparison with males. Diabetes was induced in pregnant rats by a single dose of streptozotocin (STZ, 50 mg/kg ip) in late gestation. Three-month-old male offspring from diabetic mothers (MODs) exhibited higher blood pressure (BP), higher renal vascular resistance (RVR), worse endothelium-dependent response to acetylcholine (ACH), and an increased constrictor response to phenylephrine (PHE) compared with those in age-matched female offspring of diabetic mothers (FODs), which were abolished by chronic tempol (1 mM) treatment. In anesthetized animals, stannous mesoporphyrin (SnMP; 40 µmol/kg iv) administration, to inhibit HO activity, increased RVR in FODs and reduced glomerular filtration rate (GFR) in MODs, without altering these parameters in control animals. When compared with MODs, FODs showed lower nitrotirosyne levels and higher HO-1 protein expression in renal homogenates. Indeed, chronic treatment with tempol in MODs prevented elevations in nitrotyrosine levels and the acute renal hemodynamics response to SnMP. Then, maternal diabetes results in sex-specific hypertension and renal alterations associated with oxidative stress mainly in adult male offspring, which are reduced in the female offspring by elevation in HO-1 expression and lower oxidative stress levels. [ABSTRACT FROM AUTHOR]

[Objectives]The aim of this study was to investigate the effects of rutin on growth, intestinal antioxidant capacity, and lipid metabolism in weaned mice. [Methods]Thirty-two 21-day old male weaned mice with similar body weight were randomly divided into 4 groups. They were fed basal diet with an addition 0（control group）,250,500 and 1 000 mg·kg-1 rutin, respectively. The experiment lasted 21 days. [Results]Compared with the control group, dietary 250,500 and 1 000 mg·kg-1 rutin had no significant effect on the body weight and organ index（liver, kidney, spleen and testis）of weaned mice. There was no significant difference in the hepatic histology among these 4 groups. For the intestinal morphology and barrier, compared with the control group, dietary 250 and 1 000 mg·kg-1 rutin significantly increased the villus height（P<0.05）,and dieatry 500 mg·kg-1 rutin significantly increased the villus width（P<0.05）and claudin 3 gene（CLDN3）mRNA expression in jejunum（P<0.05）. For the antioxidation, the activity of total superoxide dismutase（T-SOD）in serum and total antioxidant capacity（T-AOC）level and T-SOD activity in jejunum increased linearly with the increasing of rutin levels（PL<0.05）. Dietary 250 and 500 mg·kg-1 rutin significantly decreased the content of malondialdehyde（MDA）（P<0.05）and increased heme oxygenase 1 gene（HO-1）mRNA expression in jejunum（P<0.05）. Dietary 500 and 1 000 mg·kg-1 rutin significantly increased catalase gene（CAT）mRNA expression in jejunum（P<0.05）. For lipid metabolism, compared with the control group, dietary 1 000 mg·kg-1 rutin significantly increased the concentration of high-density lipoprotein cholesterol（HDL-C）in serum（P<0.05）,and 250 and 500 mg·kg-1 rutin significantly decreased serum triglyceride（TG）concentration（P<0.05）. The mRNA expression of peroxisome proliferator-activated receptor γ gene（PPARγ）was significantly decreased by adding 1 000 mg·kg-1 rutin（P<0.05）and the mRNA expression of fatty acid synthase gene（FASN）was significantly decreased by adding 250,500 and 1 000 mg·kg-1 rutin（P<0.05）. However, there was no significant effect on the mRNA expressions of peroxisome proliferator-activated receptor α gene（PPARα）,acetyl-CoA carboxylase alpha gene（ACACA）and stearoyl-CoA desaturase 1 gene（SCD1）in jejunum. [Conclusions]Dietary rutin could improve intestinal morphology and barrier, enhance the antioxidant capacity, and reduce serum lipid of weaned mice, and its optimum dosage was 500 mg·kg-1. [ABSTRACT FROM AUTHOR]

Excessive activity of osteoclasts contributes to skeletal diseases such as osteoporosis and osteolysis. However, current drugs targeting osteoclast have various deficiencies, placing natural compounds as substitutions of great potential. Roburic acid (RA) is a triterpenoid exacted from Radix Gentianae Macrophyllae, which exhibits inhibitory effects on inflammation and oxidation. By employing an in vitro osteoclastogenesis model, this study investigates the effects and mechanisms of RA on intracellular signaling induced by receptor activator of nuclear factor‐κB ligand (RANKL). As expected, RA at a concentration scope from 1 to 10 μM dampened the osteoclast differentiation of bone marrow macrophages (BMMs) but without cell toxicity. Interestingly, RA showed no effect on osteoblastogenesis in vitro. Furthermore, RA mitigated F‐actin ring formation, hydroxyapatite resorption, and gene expression in osteoclasts. Mechanistically, RA suppressed TNF receptor‐associated factor 6 (TRAF6), the crucial adaptor protein following RANKL‐RANK binding. On the one hand, RA downregulated the nuclear factor‐κB (NF‐κB) activity, extracellular regulated protein kinases (ERK) phosphorylation, and calcium oscillations. On the other hand, RA upregulated the antioxidative response element (ARE) response and the protein expression of heme oxygenase (HO)‐1. These upstream alterations eventually led to the suppression of the nuclear factor of activated T cells 1 (NFATc1) activity and the expression of proteins involved in osteoclastogenesis and bone resorption. Furthermore, by using an ovariectomized (OVX) mice model, RA was found to have therapeutic effects against bone loss. On account of these findings, RA could be used to restrain osteoclasts for treating osteoporosis and other osteolytic diseases. [ABSTRACT FROM AUTHOR]

Doxorubicin (DOX) is an effective anthracycline chemotherapeutic drug. Nevertheless, the cardiotoxicity adverse effect restricts its clinical benefit. Allyl isothiocyanate (AITC) is a natural antioxidant and anti-inflammatory agent. In the present study, we investigated the effect of AITC on cardiotoxicity of DOX. Thirty-two adult male albino rats were divided into four groups; control, AITC, DOX, and AITC + DOX. AITC was administrated orally (25 mg/kg/day) for 7 days, and DOX was given as a single i.p. injection (15 mg/kg) on the third day. Mortality rate was observed during the experiment. Cardiac toxicity markers (lactate dehydrogenase (LDH), creatine kinase (CK-MB), and cardiac Troponin I (cTn-I)) were evaluated in serum samples obtained from all groups after 48 hours of DOX injection. DOX-treated group showed 40% mortality and a significant increase in cardiac enzymes. This increase was accompanied by degenerated cardiomyocytes, and inflammatory cells infiltrates. Interestingly, AITC administration alleviated myocardial oxidative stress induced by DOX as attenuated the increase in malondialdehyde (MDA), and nitric oxide (NO) while resulted in elevations of the antioxidant reduced glutathione (GSH) level as well as superoxide dismutase (SOD) activity. Furthermore, the inflammatory cytokine, TNF-α, was reduced upon administration of AITC with DOX. The cardio-protection of AITC is attributed to increase the expression of cytoprotective nuclear factor erythroid 2-related factor 2 (Nrf2). Subsequently, heme oxygenase 1 (HO-1) level was elevated by AITC to correct the oxidative stress induced by DOX in the heart. Accordingly, AITC ameliorated acute cardiotoxicity associated with DOX treatment via attenuation of oxidative stress and the induced-tissue inflammatory injury. Abbreviations: DOX: doxrubicin; Nrf2: nuclear factor erythroid 2-related factor 2; HO-1: heme oxygenase 1; AITC: ally isothiocyanate; MDA: malondialdehyde; SOD: superoxide dismutase; GSH: reduced glutathione; TNF-α: tumor necrosis factor alpha. [ABSTRACT FROM AUTHOR]

Introduction: Platelet sequestration, inflammation, and inappropriate coagulation cascade activation are prominent in liver xenotransplant models and are associated with poor outcomes. Here, we evaluate a cassette of six additional genetic modifications to reduce anti‐pig antibody binding (α‐1,3‐galactosyl transferase knockout [GalTKO]) and target coagulation dysregulation (human endothelial protein C receptor [hEPRC] and thrombomodulin [hTBM]), complement pathway regulation (human membrane cofactor protein, hCD46), inflammation heme oxygenase 1 [hHO‐1]), and a self‐recognition receptor (integrin‐associated protein [hCD47]), as well as donor pharmacologic treatments designed to blunt these phenomena. Methods: Livers from GaltKO.hCD46 pigs ("2‐gene," n = 3) and GalTKO.hCD46 pigs also transgenic for hEPRC, hTBM, hCD47, and hHO‐1 ("6‐gene," n = 4) were perfused ex vivo with whole human blood. Six‐gene pigs were additionally pretreated with desmopressin (DDAVP) and clodronate liposomes to deplete vWF and kupffer cells, respectively. Results: The average perfusion times increased from 304 (±148) min in the 2‐gene group to 856 (±61) min in the 6‐gene group (p =.010). The average heparin administration was decreased from 8837 U/h in the 2‐gene to 1354 U/h in the 6‐gene group (p =.047). Platelet sequestration tended to be delayed in the 6‐gene group (p =.070), while thromboxane B2 (TXB2, a platelet activation marker) levels were lower over the first hour (p =.044) (401 ± 124 vs. 2048 ± 712 at 60 min). Thrombin production as measured by F1+2 levels tended to be lower in the 6‐gene group (p =.058). Conclusions: The combination of the hEPCR.hTBM.hCD47.hHO‐1 cassette along with donor pig DDAVP and clodronate liposome pretreatment was associated with prolonged function of xenoperfused livers, reduced coagulation pathway perturbations, and decreased TXB2 elaboration, and reflects significant progress to modulate liver xenograft injury in a pig to human model. [ABSTRACT FROM AUTHOR]

Background: Estrogen deficiency is one of the main causes of cardiovascular diseases (CVDs) after menopause, accompanied with the upregulation of oxidative stress. Two isoforms of heme oxygenase (HO), HO-1 and HO-2, have been implicated in the cytoprotective effects via the antioxidant and anti-inflammatory capacities. Aims: This study aimed to investigate the time-course of HO-1 and HO-2 expression in the cardiac tissue of ovariectomized rats and whether oxidative stress is involved in the regulation of HO alteration. Methods: Adult female rats were ovariectomized bilaterally to induce estrogen deficiency and randomly divided into (1) Sham, (2) ovariectomy (Ovx), (3) Ovx + E2 (17β estradiol, 50 μg/kg/day, intramuscular), and (4) Ovx + tempol (1 mM in drinking water, a superoxide dismutase [SOD] mimetic). Rats were sacrificed 12 weeks after Ovx; blood and myocardium samples were collected. Results: Showed that plasma E2 levels of Ovx and Ovx + tempol groups were significantly reduced as compared to Sham group after 4 weeks of Ovx. Superoxide anion in the cardiac tissue was significantly elevated 2 weeks after Ovx, and the increase was drastically reversed by the treatment with E2 and tempol. In addition, Ovx rats showed significantly higher levels of oxidized glutathione (GSSG) than those of Sham group, which were also significantly reduced by E2 and tempol administration. Western blot analysis indicated that HO-1 expression was significantly induced 1 week after Ovx and sustained at high levels until 12 weeks. E2 replacement did not immediately reverse HO-1 until treatment for 4 weeks as well as tempol administration for 5 weeks. Expression of the constitutive enzymes HO-2 did not show significant differences between Sham and Ovx groups, and E2 or tempol administration had no effect on cardiac HO-2 protein expression. Conclusion: E2 deficiency induced upregulation of superoxide anion in the myocardium, which might be the major contributor to the sustained HO-1 expression as adaptive responses to oxidative stress. This study provides new insight into the pathogenesis of CVDs after menopause.

Relevance. The increase in the number of severe brain injuries due to stroke and traumatic brain injury determines the need to study and develop effective strategies for neuroprotection. The article highlights new mechanisms of the neuroprotective action of the inhalation anesthetic xenon based on the data of our own experimental studies.Aim of study. To assess the effect of anesthesia with xenon at a concentration of 0.5 MAC (minimum alveolar concentration) on the phosphorylation of glycogen synthase kinase 3β (GSK-3β) and the content of antioxidant defense enzymes in the rat brain.Material and methods. The effect of inhalation anesthesia with xenon on the phosphorylation of the GSK-3β enzyme in comparison with lithium chloride, as well as on the content of heme oxygenase, catalase, and Mn-superoxide dismutase in rat brain homogenates was studied by immunoblotting.Results. The use of xenon at a concentration of 0.5 MAA causes an almost twofold increase in the content of the phosphorylated form of the GSK-3β enzyme in comparison with the control (p

Background and purposeExhaled carbon monoxide (CO) is associated with cardiometabolic traits, subclinical atherosclerosis, and cardiovascular disease, but its specific relations with stroke are unexplored. We related exhaled CO to magnetic resonance imaging measures of subclinical cerebrovascular disease cross-sectionally and to incident stroke/transient ischemic attack prospectively in the Framingham Offspring study.MethodsWe measured exhaled CO in 3313 participants (age 59±10 years; 53% women), and brain magnetic resonance imaging was available in 1982 individuals (age 58±10 years; 54% women). Participants were analyzed according to tertiles of exhaled CO concentration.ResultsIn age- and sex-adjusted models, the highest tertile of exhaled CO was associated with lower total cerebral brain volumes, higher white-matter hyperintensity volumes, and greater prevalence of silent cerebral infarcts (P

Infertility is believed to be triggered by endometriosis whose pathophysiology and the etiology is still unknown. Certain genes play pivotal roles in pathogenesis of endometriosis. Natural products and plants are used as important sources for production of new drugs. The current study assesses the effects of gamma-oryzanol (GO) in a rat model with surgically induced endometriosis. The experimental endometriosis was induced in 24 wistar rats, and the animals were subsequently subdivided into endometriosis-sole (endom group), 3000 and 6000 µg/kg GO (GO-3000 and GO-6000) and Vit C groups. The protein levels of estrogen receptor-alpha (ER-α), Steroidogenic factor 1 (SF1), Sirtuin 1 (SIRT1), heme oxygenase 1 (HO1), light chain 3 (LC3B) and Beclin1 (BECN1) were assessed. TUNEL staining was used for detecting the apoptosis rate. The results revealed that protein levels of SF1, HO1, and total LC3B significantly (P < 0.05) decreased in GO-6000-treated groups compared to endom group. Moreover, the protein level of BECN1 and SIRT-1 significantly (P < 0.05) increased in GO-6000-treated groups compared to endom group. GO treatment did not imply any significant difference (P > 0.05) concerning the protein levels of ER-α. The TUNEL staining results showed higher TUNEL-positive cells reactions in the rats treated with GO-6000 and Vit C. Thus, GO is involved in improving condition rats involved with endometriosis through modulation in the protein levels of some molecules and also induction of apoptosis. [ABSTRACT FROM AUTHOR]

All drugs that can penetrate the blood-brain barrier (BBB) may lead to mental state changes, including the widely used anti-infective drug sulfamethoxazole (SMZ). Herein, we investigated whether lycopene (LYC) could ameliorate SMZ-induced brain injury and the postulated mechanisms involved. A total of 120 grass carps were exposed under SMZ (0.3 μg/L, waterborne) or LYC (10 mg/kg fish weight, diet) or their combination for 30 days. Firstly, brain injury induced by SMZ exposure was suggested by the damage of BBB (decreases of Claudins, Occludin and Zonula Occludens), and the decrease of neurotransmitter activity (AChE). Through inducing oxidative stress (elevations of malondialdehyde and 8-hydroxy-2 deoxyguanosine, inhibition of glutathione), SMZ increased the intra-nuclear level of NF-κB and its target genes (TNF-α and interleukins), creating an inflammatory microenvironment. As a positive feed-back mechanism, apoptosis begins with activation of pro-death proteins (Bax/Bcl-2) and activation of caspases (caspase-9 and caspase-3). Meanwhile, a compensatory upregulation of constitutive Nrf2 and its downstream antioxidative gene expression (NAD(P)H Quinone Dehydrogenase 1 and Heme oxygenase 1) and accelerated autophagy (increases of autophagy-related genes and p62 inhibition) were activated as a defense mechanism. Intriguingly, under SMZ stress, LYC co-administration decreased NF-κB/apoptosis cascades and restored Nrf2/autophagy levels. The neuroprotective roles of LYC make this natural compound a valuable agent for prevention SMZ stress in environment. This study suggests that LYC might be developed as a potential candidate for alleviating environmental SMZ stress in aquaculture. • Sulfamethoxazole exposure leads to oxidative stress, inflammation and apoptosis in the brain. • Lycopene supplementation ameliorates brain damage induced by Sulfamethoxazole. • Lycopene exerts neuroprotection by rebalance of NF-κB/Nrf2 pathway. [ABSTRACT FROM AUTHOR]

Background: Red blood cell-induced cerebral inflammation and toxicity has been shown to be attenuated by induction of the heme-catalyzing enzyme, hemoxygenase-1 (HO-1), in animal models of subarachnoid hemorrhage (SAH). Although inflammatory mechanisms leading to secondary neuronal injury in SAH are becoming increasingly well understood, markers of cerebral inflammation have so far not been implemented in clinical prediction models of SAH. Methods: In this biomarker observational study, HO-1 messenger ribonucleic acid (mRNA) expression levels were determined in cerebrospinal fluid (CSF) and blood of 66 patients with aneurysmal SAH on days 1, 7, and 14 after the SAH event. HO-1 mRNA expression was determined via real time polymerase chain reaction (PCR), and relative expression changes were quantified in comparison with expression levels in nonhemorrhagic control CSF. Subarachnoid blood burden, as well as presence of vasospasm and delayed cerebral ischemia (DCI), were recorded. Short and long-term clinical outcomes were assessed using the Modified Rankin Scale at discharge and 1 year after the SAH event. Results: CSF HO-1 expression levels showed a significant increase over the 14-day observation period (p < 0.001, F = 22.53) and correlated with intracranial hematoma burden (ρ = 0.349, p = 0.025). In multivariate analyses, CSF HO-1 expression levels did not reach significance as independent predictors of outcome. Vasospasm on computed tomographic angiography was associated with lower CSF HO-1 expression levels on day 7 after SAH (n = 53, p = 0.010), whereas patients with DCI showed higher CSF HO-1 expression levels on day 14 after SAH (n = 21, p = 0.009). Conclusions: HO-1 expression in CSF in patients with SAH follows a distinct temporal induction pattern and is dependent on intracranial hematoma burden. CSF HO-1 expression was unable to predict functional outcome. Associations of early low HO-1 expression with vasospasm and late elevated HO-1 expression with DCI may point to detrimental effects of late HO-1 induction, warranting the need for further investigation in a larger study population. [ABSTRACT FROM AUTHOR]

Aims: Nonsteroidal anti-inflammatory drugs, including ketoprofen, induce adverse effects within the gastrointestinal (GI)-tract. Hydrogen sulfide (H2S) is an antioxidative gaseous mediator contributing to GI-protection. We aimed to evaluate the GI safety of a novel H2S-releasing derivative of ketoprofen (ATB-352) versus classic ketoprofen and the molecular mechanisms of their activity after chronic treatment in experimental animal models. Results: Ketoprofen (10 mg/kg/day) administered intragastrically for 7 days in contrast with ATB-352 (14 mg/kg/day) reduced mucosal H2S content inducing GI damage with significantly increased injury score, altered intestinal microbiome profile, and modulation of more than 50% of 36 investigated molecular sensors (e.g., mammalian target of rapamycin or suppressor of cytokine signaling 3 [SOCS3]). Polypharmacy with aspirin (10 mg/kg/day) enhanced ketoprofen toxicity not affecting GI safety of ATB-352. Omeprazole (20 mg/kg/day) decreased ketoprofen-induced injury to the level of ATB-352 alone. Both compounds combined or not with aspirin or omeprazole maintained the ability to inhibit cyclooxygenase (COX) activity manifested by decreased prostaglandin production. Innovation and Conclusions: Ketoprofen-induced H2S-production decrease and intestinal microbiome profile alterations lead to GI toxicity observed on macro-/microscopic and molecular levels. Ketoprofen but not ATB-352 requires concomitant treatment with omeprazole to eliminate GI adverse effects. ATB-352 applied alone or in a polypharmacy setting with aspirin effectively inhibited COX and maintained GI safety due to H2S-release. Neither compound affected DNA oxidation in the GI mucosa, but ATB-352 had lower impact on molecular oxidative/inflammatory response pathways and intestinal microbiome. The GI safety of ATB-352 could be due to the involvement of heme oxygenase 1 and SOCS3 pathway activation. Antioxid. Redox Signal. 36, 189–210. [ABSTRACT FROM AUTHOR]

The prenylated xanthones compounds, macluraxanthone B (MCXB) was isolated from the MeOH extracts of Cudrania tricuspidata. In this study, we investigated the effect of MCXB on inflammatory response. Anti-inflammatory effects of MCXB were examined in lipopolysaccharide (LPS)-stimulated RAW264.7 and BV2 cells. We observed their anti-inflammatory effects by ELISA, western blot analysis, and immunofluorescence. MCXB significantly inhibited the LPS-stimulated production of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-α in RAW264.7 and BV2 cells. MCXB also reduced the LPS-induced expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 proteins. Incubating cells with MCXB prevented subsequent activation of the nuclear factor kappa B (NF-κB) signaling pathway by inhibiting the nuclear localization and DNA-binding activity of the p65 subunit induced by LPS. MCXB inhibited the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 mitogen-activated protein kinases (MAPKs) in RAW264.7 and BV2 cells. MCXB induced the expression of heme oxygenase (HO)-1 protein, and the inhibitory effect of MCXB on nitric oxide production was partially reversed by a selective HO-1 inhibitor. Our results suggested that the anti-inflammatory effect of MCXB is partly regulated by HO-1 induction. In conclusion, MCXB could be a useful candidate for the development of therapeutic and preventive agents to treat inflammatory diseases. [ABSTRACT FROM AUTHOR]

Heme is an essential biomolecule and cofactor involved in a myriad of biological processes. In this review, we focus on how heme binding to heme regulatory motifs (HRMs), catalytic sites, and gas signaling molecules as well as how changes in the heme redox state regulate protein structure, function, and degradation. We also relate these heme-dependent changes to the affected metabolic processes. We center our discussion on two HRM-containing proteins: human heme oxygenase-2, a protein that binds and degrades heme (releasing Fe2+ and CO) in its catalytic core and binds Fe3+-heme at HRMs located within an unstructured region of the enzyme, and the transcriptional regulator Rev-erbβ, a protein that binds Fe3+-heme at an HRM and is involved in CO sensing. We will discuss these and other proteins as they relate to cellular heme composition, homeostasis, and trafficking. In addition, we will discuss the HRM-containing family of proteins and how the stability and activity of these proteins are regulated in a dependent manner through the HRMs. Then, after reviewing CO-mediated protein regulation of heme proteins, we turn our attention to the involvement of heme, HRMs, and CO in circadian rhythms. In sum, we stress the importance of understanding the various roles of heme and the distribution of the different heme pools as they relate to the heme redox state, CO, and heme binding affinities. [ABSTRACT FROM AUTHOR]

The heavy metal cadmium (Cd2+) is an environmental pollutant that poses serious health hazards. Due to the increasing contamination of aquatic systems with Cd2+, the increased accumulation of Cd2+ in fish has become a food safety and public health concern. Heme oxygenase (HO) is an important antioxidant enzyme that plays a key role in defending the body against oxidative damage, but little research has been done in common carp. In this study, 6 HO genes were identified in the common carp genome database. Comparative genomics analysis showed considerable expansion of the HO genes and verified the four-round whole genome duplication (WGD) event in common carp. Phylogenetic analysis revealed that all HO genes of common carp were clustered into orthologous groups, indicating high conservation during evolution. In addition, the tissue distribution results showed that most HO genes had extensive tissue distribution and showed tissue-specific expression patterns. Exposure to 0.5 mg/L Cd2+ significantly reduced the expression of TGF-β and IL-10 in common carp, which may indicate that Cd2+ exposure can destroy the physical barrier function of the intestine, inhibit intestinal immune defense and induce intestinal inflammation. To find a suitable concentration of Bacillus coagulans that could activate HO-1 genes and the immunity of the organism, we investigated the changes in HO-1 gene expression levels in the intestinal tract of common carp under Cd2+ stress at 30 days and 60 days by adding different concentrations of B. coagulans to the feed. Compared with the Cd2+ stress group without supplementation, the expression levels of the HO-1 gene in the gut of three different concentrations of B. coagulans were almost increased. And B. coagulans with L2 concentrations had better activation effect on the HO-1 gene. Similarly, compared to the Cd2+ stressed group, adding B. coagulans to the diet can almost cause the early upregulation of IL-10 and TGF-β genes. Therefore, the addition of appropriate concentrations of B. coagulans may be a good way to activate HO-1, IL-10, and TGF-β genes, reduce oxidative damage, and encourage the immune. [ABSTRACT FROM AUTHOR]

Objective To investigate the preventive effect of intraperitoneal injection of hydrogen-rich fluid on acute lung injury in rats induced by myocardial ischemia/reperfusion (I/R) and its mechanism. Methods Adult male SD rates were randomly divided into four groups: I/R + hydrogen-rich fluid+HO-1 inhibitor group (inhibitor group), myocardial I/R+hydrogen-rich fluid group (HS group), I/R group, and sham operation group (S group). The rat model of acute lung injury induced by myocardial I/R was established by ligation of coronary artery. Rats in the inhibitor group were treated with intraperitoneal injection of zinc-protoporphyrin IX (ZnPPIX, 25 mg/kg) at 30 min before operation. Rats in the inhibitor group and HS group were injected intraperitoneally with hydrogen-rich fluid (10 mL/kg) at 5 min before reperfusion, respectively. For rats in the I/R group, we successively separated and ligated the left anterior descending coronary arteries for 30 min and loosened them for 120 min. Rats in the S group underwent thoracotomy without artery ligation. At 2 hafter myocardial reperfusion, the bronchoalveolar lavage fluid was obtained to detect the total protein concentration; serum and lung tissues were collected to detect the levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-10 (IL-10) and heme oxygenase-1 (HO-1) by enzyme-linked immune sorbent assay (ELISA) ；wet/dry (W/D) of lung tissues was tested; the histopathologic changes were observed by htoxylin-eosin (HE) staining, and lung injury score was assessed; the expression of HO-1 of lung tissues was detected by Western blotting. Results Compared with the S group, the total protein concentration in BALF, W/D of lung tissues and the lung injury score, the levels of TNF-α, IL1β, and IL-10 in the serum and lung tissues, and the level and the concentration of HO-1 protein in the lung tissues were higher in the I/R group, HS group, and inhibitor group (all P<0. 05). Compared with the I/R group, the total protein concentration in BALF, W/D of lung tissues and the lung injury score were significantly lower (all P<0. 05) ；the levels of TNF-α and IL-1β in the serum and lung tissues were lower but the level of IL-10 was higher; the level and the con‐ centration of HO-1 protein in the lung tissues were higher in the HS group (all P<0. 05). Compared with the HS group, the total protein concentration in BALF, W/D of lung tissues and the lung injury score were significantly higher (all P<0. 05) ； the levels of TNF-α and IL-1β were higher but the level of IL-10 was lower (all P<0. 05) ；the level and the concentration of HO-1 protein in the lung tissues were lower in the inhibitor group (both P<0. 05). Conclusion Hydrogen-rich fluid can obviously alleviate acute lung injury in rats induced by myocardial I/R through up-regulating HO-1 to suppress the inflammation of lung tissues. [ABSTRACT FROM AUTHOR]

Inhaled chemical/material exposures are a ubiquitous part of daily life around the world. There is a need to evaluate potential adverse effects of both single and repeat exposures for thousands of chemicals and an exponentially larger number of exposure scenarios (eg, repeated exposures). Meeting this challenge will require the development and use of in vitro new approach methodologies (NAMs); however, 2 major challenges face the deployment of NAMs in risk assessment are (1) characterizing what apical outcome(s) acute assays inform regarding the trajectory to long-term events, especially under repeated exposure conditions, and (2) capturing interindividual variability as it informs considerations of potentially susceptible and/or vulnerable populations. To address these questions, we used a primary human bronchial epithelial cell air-liquid interface model exposed to ozone (O3), a model oxidant and ubiquitous environmental chemical. Here we report that O3-induced proinflammatory gene induction is attenuated in repeated exposures thus demonstrating that single acute exposure outcomes do not reliably represent the trajectory of responses after repeated or chronic exposures. Further, we observed 10.1-, 10.3-, 14.2-, and 7-fold ranges of induction of interleukin (IL)-8, IL-6, heme oxygenase 1, and cyclooxygenase 2 transcripts, respectively, within in our population of 25 unique donors. Calculation of sample size estimates that indicated that 27, 24, 299, and 13 donors would be required to significantly power similar in vitro studies to identify a 2-fold change in IL-8, IL-6, HMOX1, and cyclooxygenase 2 transcript induction, respectively, to inform considerations of the uncertainty factors to reflect variability within the human population for in vitro studies. [ABSTRACT FROM AUTHOR]

MhuD is a noncanonical heme oxygenase (HO) from Mycobacterium tuberculosis (Mtb) that catalyzes unique heme degradation chemistry distinct from canonical HOs, generating mycobilin products without releasing carbon monoxide. Its crucial role in the Mtb heme uptake pathway has identified MhuD as an auspicious drug target. MhuD is capable of binding either one or two hemes within a single active site, but only the monoheme form was previously reported to be enzymatically active. Here we employed resonance Raman (rR) spectroscopy to examine several factors proposed to impact the reactivity of mono- and diheme MhuD, including heme ruffling, heme pocket hydrophobicity, and amino acid-heme interactions. We determined that the distal heme in the diheme MhuD active site has negligible effects on both the planarity of the His-coordinated heme macrocycle and the strength of the Fe-NHis linkage relative to the monoheme form. Our rR studies using isotopically labeled hemes unveiled unexpected biomolecular dynamics for the process of heme binding that converts MhuD from mono- to diheme form, where the second incoming heme replaces the first as the His75-coordinated heme. Ferrous CO-ligated diheme MhuD was found to exhibit multiple Fe-C-O conformers, one of which contains catalytically predisposed H-bonding interactions with the distal Asn7 residue identical to those in the monoheme form, implying that it is also enzymatically active. This was substantiated by activity assays and MS product analysis that confirmed the diheme form also degrades heme to mycobilins, redefining MhuD's functional paradigm and further expanding our understanding of its role in Mtb physiology. [ABSTRACT FROM AUTHOR]

To explore the molecular mechanism of antioxidant damage of Achyranthes bidentata and Radix Paeoniae Alba is the main objective of study. Rats were treated with Achyranthes bidentata and Radix Paeoniae Alba. The total protein, nuclear protein and total ribonucleic acid were extracted. The protein levels and messenger ribonucleic acid levels were detected by western blot and quantitative polymerase chain reaction, respectively. The apoptosis of cells was detected and the cell viability and clone formation experiments were carried out. The serum malondialdehyde content of the Achyranthes bidentata and white peony group was lower than that of the control group, while the superoxide dismutase activity was higher than that of the control group, which was statistically significant (p<0.05). The level of nuclear factor erythroid 2-related factor 2 protein in the nucleus increased after treatment with medicated serum. The protein levels and the messenger ribonucleic acid levels of heme oxygenase 1 and superoxide dismutase increased significantly (p<0.05). The percentage of apoptosis, increased cell viability and number of clones treated with medicated serum were significantly higher than those treated with serum, indicating that the compatibility of Achyranthes bidentata and white peony can promote the survival of cells under oxidative stress. Under the joint action of protein kinase C delta and protein kinase, Achyranthes bidentata and Radix Paeoniae Alba up-regulate the expression of antioxidant enzymes. [ABSTRACT FROM AUTHOR]

Heme oxygenase (HO) is an enzyme that breaks down heme and as a result iron is recycled in most organisms, including the human body. This enzyme produces bilirubin, divalent iron, and carbon monoxide. Heme Oxygenase was first described in the late 1960s [1-3]. Study of the reaction of the peripheral substituents on the heme ring with verdohemes offers models that are not very well known. In this project, a computational study of destruction reaction of verdoheme iron (ii) was carried out and the role of lateral substitutionson its hydrolysis process was investigated. Theoretical calculations show that the rate of hydrolysis reaction is slower for complexes containing peripheral substitutions. On the other hand, hydrolysis of verdohemes non-environmental is a convenient parameter for energy. To better understand this process, theoretical calculations were performed using the DFT method. Calculations of the stability energy of the compounds showed that the higher the intermolecular interactions of hydrogen, the greater the stability of the compound. Also, the highest stability energy is related to compound D, which has more intermolecular interactions from type of the hydrogen bonds. [ABSTRACT FROM AUTHOR]

Bisphenol A (BPA) is an estrogen‐like compound, and an environmental hormone, that is commonly used in daily life. Therefore, it may enter the human body through food or direct contact, causing BPA residues in blood and urine. Because most studies focused on the analysis of BPA in reproductive cells or tissues, regarding evidence the effect of BPA on human retinal pigment epithelium (ARPE‐19) cells unavailable. Accordingly, the present study explored the cytotoxicity of BPA on ARPE‐19 cells. After BPA treatment, the expression of Bcl‐XL an antiapoptotic protein, in the mitochondria decreased, and the expression of Bax, a proapoptotic protein increased. Then the mitochondrial membrane potential was affected. BPA changed in mitochondrial membrane potential led to the release of cytochrome C, which activated caspase‐9 to promote downstream caspase‐3 leading to cytotoxicity. The nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2) and heme oxygenase 1 (HO‐1) pathway play a major role in age‐related macular degeneration. Our results showed that expression of HO‐1 and Nrf2 suppressed by BPA. Superoxide dismutase and catalase, which Nrf2 downstream antioxidants, were degraded by BPA. AMP‐activated kinase (AMPK), which can regulate the phosphorylation of Nrf2, and the phosphorylation of AMPK expression was reduced by BPA. Finally, BPA‐induced ROS generation and cytotoxicity were reduced by N‐acetyl‐l‐cysteine. Taken together, these results suggest that BPA induced ARPE‐19 cells via oxidative stress, which was associated with down regulated Nrf2/HO‐1 pathway, and the mitochondria dependent apoptotic signaling pathway. [ABSTRACT FROM AUTHOR]

Heme oxygenase 1 (HO-1, encoded by the HMOX1 gene) is the rate-limiting enzyme that catalyzes heme degradation, and it has been reported to exert antioxidative effects. Recently, decidualization has been reported to confer resistance to environmental stress signals, protecting against oxidative stress. However, the effects and regulatory mechanism of HO-1 in decidual stromal cells (DSCs) during early pregnancy remain unknown. Here, we verified that the levels of HO-1 and heme in DSCs are increased compared with those in endometrial stromal cells. Additionally, the upregulation of HIF1A expression led to increased HMOX1 expression in DSCs possibly via nuclear factor erythroid 2-related factor (encoded by the NFE2L2 gene). However, addition of the competitive HO-1 inhibitor zinc protoporphyrin IX resulted in an increase in HIF1A expression. Hydrogen peroxide (H2O2) induced the production of reactive oxygen species (ROS), decreased the cell viability of DSCs in vitro, and upregulated the level of heme. As an HO-1 inducer, cobalt protoporphyrin IX decreased ROS production and significantly reversed the inhibitory effect of H2O2 on cell viability. More importantly, patients with unexplained spontaneous abortion had low levels of HO-1 that were insufficient to protect against oxidative stress. This study suggests that the upregulation of HO-1 expression via HIF1A protects DSCs against excessive hememediated oxidative stress. Furthermore, the excessive oxidative stress injury and impaired viability of DSCs associated with decreased HO-1 expression should be associated with the occurrence and/or development of spontaneous abortion. [ABSTRACT FROM AUTHOR]

Objectives: We conducted inhalation and intratracheal instillation studies in order to examine the effects of tungsten trioxide (WO3) nanoparticles on the lung, and evaluated whether or not the nanoparticles would cause persistent lung inflammation. Methods: In the inhalation study, male 10‐week‐old Fischer 334 rats were classified into 3 groups. The control, low‐dose, and high‐dose groups inhaled clean air, 2, and 10 mg/m3 WO3 nanoparticles, respectively, for 6 h each day for 4 weeks. The rats were dissected at 3 days, 1 month, and 3 months after the inhalation, and the bronchoalveolar lavage fluid (BALF) and lung tissue were examined. In the intratracheal instillation study, male 12‐week‐old Fischer 334 rats were divided into 3 subgroups. The control, low‐dose, and high‐dose groups were intratracheally instilled 0.4 ml distilled water, 0.2, and 1.0 mg WO3 nanoparticles, respectively, dissolved in 0.4 ml distilled water. The rats were sacrificed at 3 days, 1 week, and 1 month after the intratracheal instillation, and the BALF and lung tissue were analyzed as in the inhalation study. Results: The inhalation and instillation of WO3 nanoparticles caused transient increases in the number and rate of neutrophils, cytokine‐induced neutrophil chemoattractant (CINC)‐1, and CINC‐2 in BALF, but no histopathological changes or upregulation of heme oxygenase (HO)‐1 in the lung tissue. Conclusion: Our results suggest that WO3 nanoparticles have low toxicity to the lung. According to the results of the inhalation study, we also propose that the no observed adverse effect level (NOAEL) of WO3 nanoparticles is 2 mg/m3. [ABSTRACT FROM AUTHOR]

The ability to obtain purified biliverdin IX (BVIX) isomers other than the commercially available BVIXα is limited due to the low yields obtained by the chemical coupled oxidation of heme. Chemical oxidation requires toxic chemicals, has very poor BVIX yields (<0.05%), and is not conducive to scalable production. Alternative approaches utilizing recombinant E. coli BL21 expressing a cyanobacterial heme oxygenase have been employed for the production BVIXα, but yields are limited by the rate of endogenous heme biosynthesis. Furthermore, the emerging roles of BVIXβ and BVIXδ in biology and their lack of commercial availability has led to a need for an efficient and scalable method with the flexibility to produce all three physiologically relevant BVIX isomers. Herein, we have taken advantage of an optimized non-pathogenic E. coli Nissle (EcN(T7)) strain that encodes an endogenous heme transporter and an integrated T7 polymerase gene. Protein production of the Pseudomonas aeruginosa BVIXβ and BVIXδ selective heme oxygenase (HemO) or its BVIXα producing mutant (HemOα) in the EcN(T7) strain provides a scalable method to obtain all three isomers, that is not limited by the rate of endogenous heme biosynthesis, due to the natural ability of EcN(T7) to transport extracellular heme. Additionally, we have optimized our previous LC-MS/MS protocol for semi-preparative separation and validation of the BVIX isomers. Utilizing this new methodology for scalable production and separation we have increased the yields of the BVIXβ and -δ isomers >300-fold when compared to the chemical oxidation of heme. [ABSTRACT FROM AUTHOR]

Lactate, historically considered a waste product of anerobic metabolism, is a metabolite in whole-body metabolism needed for normal central nervous system (CNS) functions and a potent signaling molecule and hormone in the CNS. Neuronal activity signals normally induce its formation primarily in astrocytes and production is dependent on anerobic and aerobic metabolisms. Functions are dependent on normal dynamic, expansive, and evolving CNS functions. Levels can change under normal physiologic conditions and with CNS pathology. A readily combusted fuel that is sshuttled throughout the body, lactate is used as an energy source and is needed for CNS hemostasis, plasticity, memory, and excitability. Diffusion beyond the neuron active zone impacts activity of neurons and astrocytes in other areas of the brain. Barriergenesis, function of the blood-brain barrier, and buffering between oxidative metabolism and glycolysis and brain metabolism are affected by lactate. Important to neuroprotection, presence or absence is associated with L-lactate and heme oxygenase/carbon monoxide (a gasotransmitter) neuroprotective systems. Effects of carbon monoxide on L-lactate affect neuroprotection – interactions of the gasotransmitter with L-lactate are important to CNS stability, which will be reviewed in this article. [ABSTRACT FROM AUTHOR]

Grub polypeptide extracts (GPEs) have antioxidant effects; however, their underlying molecular mechanisms are unknown. This study explored the antioxidant molecular mechanism of GPE via the nuclear factor-erythroid 2-related factor 2 (NRF2)-antioxidant response element (ARE) signaling pathway in C2C12 muscle satellite cells exposed to oxidative stress. The effects of GPE/or H2O2 on C2C12 were investigated by the MTT (3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) viability assay and immunofluorescence and small interfering RNA (siRNA) analyses. The cell viability, cell damage, intracellular reactive oxygen species (ROS) levels, and NRF2 signaling pathways related to proteins were measured. GPE significantly increased the antioxidant capacity of cells, evident by increased cell viability and decreased lactate dehydrogenase leakage, DNA damage, malondialdehyde content, and ROS level. GPE also markedly increased mRNA expression levels and activities of antioxidant enzymes including superoxidase 1 and 2, catalase, and glutathione peroxidase. In addition, GPE increased the gene and protein expression of NRF2 and heme oxygenase 1 by promoting NRF2 translocation from the cytoplasm to the nucleus and activating NRF2-ARE signaling pathways. The antioxidant effects of GPE through these signaling pathways were further confirmed by NRF2-specific siRNA silencing. Thus, GPE enhances antioxidant capacity and alleviates oxidative damage of C2C12 cells via the NRF2-ARE signaling pathway. [ABSTRACT FROM AUTHOR]

Polymyxin B (PMB) is increasingly used as a last-line antibiotic; however, the emergence of PMB resistance is a serious threat to global health. Here, a total of 40 Acinetobacter baumannii clinical isolates were collected to screen for PMB-resistant strains. Several clinical isolates including NCCP 16007 were far more resistant to PMB (MIC: 128–256 μg/ml) than the ATCC 17978 strain (MIC: 2 μg/ml) and appeared to possess resistance to broad-spectrum antibiotics including meropenem and 12 others. Four highly PMB-resistant strains possessed point mutations in the histidine kinase PmrB, leading to an increased expression of pmrC encoding a phosphoethanolamine transferase. Whole-genome analyses revealed that the NCCP 16007 stain had acquired two additional copies of the pmrC gene with phage integrase and 13 antibiotic resistance genes (ARGs) from other pathogens, including Klebsiella pneumoniae and Pseudomonas aeruginosa. The GC ratios of the ARGs (50–60%) were higher than that of the chromosomal backbone (39.06%), further supporting the horizontal gene transfer of ARGs. Comparative genomics with other multidrug-resistant A. baumannii strains revealed that the NCCP 16007 strain has many additional ARGs and has lost several virulence factors including Csu pili and heme oxygenase but exhibited high pathogenicity in Galleria mellonella-infection models. The observation of condensed biofilm through confocal and scanning electron microscopy suggested that the NCCP 16007 strain may possess high adhesion capacity during urinary tract infection. Therefore, our genomic and phenotypic analyses suggested that the multidrug-resistant A. baumannii NCCP 16007 strain possesses high genome plasticity, natural transformation ability, and pathogenicity. [ABSTRACT FROM AUTHOR]

Chitosan oligosaccharide (COS), hydrolyzed and deacetylated from chitosan, has been reported to possess varieties of biological activities. Alzheimer's disease (AD) is a multifactorial progressive neurodegenerative disorder characterized by cognitive decline and memory loss, where oxidative stress was reported to be an overwhelming cause of the occurrence of AD. We have previously reported that COS could significantly decrease cell death, ROS generation, and lipid peroxidation, though the potential mechanism was yet to be determined. This study was designed to investigate the neuroprotective effect of COS against hydrogen peroxide (H2O2)-induced oxidative stress and apoptosis in neuronal SH-SY5Y cells. Our results indicated that COS could dose-dependently scavenge H2O2 in the cell-free systems. Accordingly, COS markedly decreased H2O2-induced cell apoptosis and intracellular ROS generation, while increased antioxidant capacity in SH-SY5Y cells. Further, COS significantly reduced the expression of Bax and upregulated Bcl-2. The mRNA and protein expression levels of nuclear Nrf2, heme oxygenase 1 (HO-1), and NAD(P)H: quinone oxidoreductase 1 (NQO1) were significantly increased upon COS treatment. Moreover, Nrf2-siRNA evidently reversed the promotive effect of COS on expression levels of HO-1 and NQO1, and ARE-driven transcriptional activity as determined by double-luciferase reporter gene assay. Besides, COS reversed H2O2-mediated increased phosphorylation of ERK1/2 and p38 MAPK. In conclusion, our findings indicate that COS could protect SH-SY5Y cells from oxidative damage and apoptosis via regulating Nrf2/ARE signaling pathway, which may provide new applications for the prevention and treatment of AD. [ABSTRACT FROM AUTHOR]

Non-small cell lung cancer (NSCLC) is often characterized by an underlying mutation in the epidermal growth factor receptor (EGFR), contributing to aggressive metastatic disease. Methyl 2-cyano-3,11-dioxo-18beta-olean-1,12-dien-30-oate (CDODA-Me), a glycyrrhetinic acid derivative, reportedly improves the therapeutic response to erlotinib (ERL), an EGFR tyrosine kinase inhibitor. In the present study, we performed a series of studies to demonstrate the efficacy of CDODA-Me (2 μM) in sensitizing HCC827R (ERL-resistant) cells to ERL. Herein, we first established the selectivity of ERL-induced drug resistance in the HCC827R cells, which was sensitized when ERL was combined with CDODA-Me (2 μM), shifting the IC 50 from 23.48 μM to 5.46 μM. Subsequently, whole transcriptomic microarray expression data demonstrated that the combination of ERL + CDODA-Me elicited 210 downregulated genes (0.44% of the whole transcriptome (WT)) and 174 upregulated genes (0.36% of the WT), of which approximately 80% were unique to the ERL + CDODA-Me group. Synergistic effects centered on losses to cell cycle progression transcripts, a reduction of minichromosome maintenance complex components (MCM2-7), all key components of the Cdc45·MCM2-7GINS (CMG) complex, and replicative helicases; these effects were tantamount to the upregulation of processes associated with the nuclear factor erythroid 2 like 2 translational response to oxidative stress, including sulfiredoxin 1, heme oxygenase 1, and stress-induced growth inhibitor 1. Collectively, these findings indicate that the synergistic therapeutic effects of ERL + CDODA-Me on resistant NSCLC cells are mediated via the inhibition of mitosis and induction of oxidative stress. [Display omitted] • Erlotinib (ERL) treatment can decrease tumor growth in non-small lung cancer (NSCLC), but benefits are limited as patients develop resistance. • For ERL resistance, combination therapy could augment efficacy and establish favorable clinical outcomes. • CDODA-Me sensitized ERL-resistant NSCLC to ERL. [ABSTRACT FROM AUTHOR]

Background and Objectives: Oxidative stress from exercise, either injured muscles and reduces performance in athletes, or stimulates the production of cytokines from many cells. body respond to oxidative stress by activating antioxidant defenses and other protective devices to counteract these body pressures. Therefore, the purpose of this study is to investigate the effect of 8 weeks of strenuous endurance training on HO-1 and TNF-α in gastrocnemius and soleus muscle tissue of male wistar rats. Material and Methods: 16 adult male Wistar rats, were randomly divided in 2 groups (control and endurance training). The strenuous endurance training protocol included running on the treadmill for 8 weeks (5 sessions per week). Standard meal and water were freely provided for the subjects. 24 hours after the last session of training and 4 hours of overnight fasting, tissue samples were collected and HO-1 and TNF-α levels were measured by ELISA method. Independent t-test was used for data analysis. Results: The results showed that 8 weeks of strenuous endurance training did not have a significant effect on the amount of HO-1 enzyme in gastrocnemius and soleus muscle (P˃0/05). Also, 8 weeks of strenuous endurance training had no significant effect on TNF-α in soleus and gastrocnemius muscle (P˃0/05). Discussion and conclusion: Due to the lack of effect of exercise on the levels of HO-1 and TNF-α, it can be said with caution that regular exercise has created a useful adaptation.

Introduction: We performed an immunohistochemical investigation of the localization of Heme oxygenase(HO-1) and bilirubin(BR)/biopyrrin(BPn) to elucidate whether a response to oxidative stress is generated in the human placenta. Methods: Placentas from nine patients with preeclampsia(PE) and seven controls were investigated. Results: For HO-1 and BR/BPn expressions, a higher number of positive cells were observed in the PE group than in the control group. Conclusions: The degree of these expressions tended to relate to the onset of PE. This suggests that the heme catabolic pathway induced by oxidative stress plays an important role in the pathophysiology of PE.

The phenomenon of heat stress leading to ferroptosis-like cell death has recently been observed in bacteria as well as plant cells. Despite recent findings, the evidence of ferroptosis, an iron-dependent cell death remains unknown in microalgae. The present study aimed to investigate if heat shock could induce reactive oxygen species (ROS) and iron-dependent ferroptotic cell death in Chlamydomonas reinhardtii in comparison with RSL3-induced ferroptosis. After RSL3 and heat shock (50 °C) treatments with or without inhibitors, Chlamydomonas cells were evaluated for cell viability and the induction of ferroptotic biomarkers. Both the heat shock and RSL3 treatment were found to trigger ferroptotic cell death, with hallmarks of glutathione–ascorbic acid depletion, GPX5 downregulation, mitochondrial dysfunction, an increase in cytosolic calcium, ROS production, lipid peroxidation, and intracellular iron accumulation via heme oxygenase-1 activation (HO-1). Interestingly, the cells preincubated with ferroptosis inhibitors (ferrostatin-1 and ciclopirox) significantly reduced RSL3- and heat-induced cell death by preventing the accumulation of Fe2+ and lipid ROS. These findings reveal that ferroptotic cell death affects the iron homeostasis and lipid peroxidation metabolism of Chlamydomonas, indicating that cell death pathways are evolutionarily conserved among eukaryotes.

Besides the clinically proven superior antimalarial activity, artemisinins (ARTs) are also associated with anticancer properties, albeit at much lower potency. Iron and heme have been proposed as possible activators of ARTs against cancer cells. Here we show that zinc protoporphyrin-9 (ZnPPIX), a heme homolog and a natural metabolite for heme synthesis during iron insufficiency, greatly enhanced the anticancer activity of dihydroartemisinin (DHA) in multiple cell lines. Using melanoma B16 and breast cancer 4T1 cells, we demonstrated ZnPPIX dramatically elevated intracellular free heme levels, accompanied by heightened reactive oxidative species (ROS) production. The tumor-suppression activity of ZnPPIX and DHA is mitigated by antioxidant vitamin E or membrane oxidation protectant ferrostatin. In vivo xenograft animal models confirmed that ZnPPIX significantly potentiated the tumor-inhibition capability of DHA while posing no apparent toxicity to the mice. The proliferating index and growth of tumors after the combinatory treatment of DHA and ZnPPIX were evidently reduced. Considering the clinical safety profiles of both DHA and ZnPPIX, their action synergy offers a promising strategy to improve the application of ARTs in our fight against cancer.

Men with sickle cell disease (SCD) frequently experience priapism, defined as prolonged, painful erections occurring without sexual arousal or desire. This urological emergency can lead to penile fibrosis and permanent erectile dysfunction if not treated adequately. Due to its complex pathophysiology, there is currently no effective preventative treatment for this condition. Recent studies have highlighted the dysfunction of the nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) pathway in erectile tissues as a critical mechanism in developing priapism in SCD. Additionally, further research indicates that intravascular hemolysis promotes increased smooth muscle relaxation in the corpus cavernosum and that excess heme may significantly contribute to priapism in SCD. Pharmacological treatments should ideally target the pathophysiological basis of the disease. Agents that reduce excess free heme in the plasma have emerged as potential therapeutic candidates. This review explores the molecular mechanisms underlying the excess of heme in SCD and its contribution to developing priapism. We discuss pharmacological approaches targeting the excess free heme in the plasma, highlighting it as a potential therapeutic target for future interventions in managing priapism., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Silveira, Calmasini, de Oliveira, Costa and Silva.)

The protein heme oxygenase (HO)-1 has been implicated in the regulations of multiple immunological processes. It is well known that kidney injury is affected by immune mechanisms and that various kidney-disease forms may be a result of autoimmune disease. The current study describes in detail the role of HO-1 in kidney disease and provides the most recent observations of the effect of HO-1 on immune pathways and responses both in animal models of immune-mediated disease forms and in patient studies.

Purpose: Heme oxygenase-1 (HO-1) is a crucial enzyme in heme metabolism, facilitating the breakdown of heme into biliverdin, carbon monoxide, and free iron. Renowned for its potent cytoprotective properties, HO-1 showcases notable antioxidant, anti-inflammatory, and anti-apoptotic effects. In this review, the authors aim to explore the profound impact of HO-1 on cardiac senescence and its potential implications in myocardial infarction (MI)., Results: Recent research has unveiled the intricate role of HO-1 in cellular senescence, characterized by irreversible growth arrest and functional decline. Notably, cardiac senescence has emerged as a pivotal factor in the development of various cardiovascular conditions, including MI. Notably, cardiac senescence has emerged as an important factor in the development of various cardiovascular conditions, including myocardial infarction (MI). The accumulation of senescent cells, spanning vascular endothelial cells, vascular smooth muscle cells, cardiomyocytes, and progenitor cells, poses a significant risk for cardiovascular diseases such as vascular aging, atherosclerosis, myocardial infarction, and ventricular remodeling. Inhibition of cardiomyocyte senescence not only reduces senescence-associated inflammation but also impacts other myocardial lineages, hinting at a broader mechanism of propagation in pathological remodeling. HO-1 has been shown to improve heart function and mitigate cardiomyocyte senescence induced by ischemic injury and aging. Furthermore, HO-1 induction has been found to alleviate H 2 O 2 -induced cardiomyocyte senescence. As we grow in our understanding of antiproliferative, antiangiogenic, anti-aging, and vascular effects of HO-1, we see the potential to exploit potential links between individual susceptibility to cardiac senescence and myocardial infarction., Conclusions: This review investigates strategies for upregulating HO-1, including gene targeting and pharmacological agents, as potential therapeutic approaches. By synthesizing compelling evidence from diverse experimental models and clinical investigations, this study elucidates the therapeutic potential of targeting HO-1 as an innovative strategy to mitigate cardiac senescence and improve outcomes in myocardial infarction, emphasizing the need for further research in this field., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The development of new or improved single fluorescent protein (FP)-based biosensors (SFPBs), particularly those with excitation and emission at near-infrared wavelengths, is important for the continued advancement of biological imaging applications. In an effort to accelerate the development of new SFPBs, we report modified transposons for the transposase-based creation of libraries of FPs randomly inserted into analyte binding domains, or vice versa. These modified transposons feature ends that are optimized to minimize the length of the linkers that connect the FP to the analyte binding domain. We rationalized that shorter linkers between the domains should result in more effective allosteric coupling between the analyte binding-dependent conformational change in the binding domain and the fluorescence modulation of the chromophore of the FP domain. As a proof of concept, we employed end-modified Mu transposons for the discovery of SFPB prototypes based on the insertion of two circularly permuted red FPs (mApple and FusionRed) into binding proteins for l-lactate and spermidine. Using an analogous approach, we discovered calcium ion (Ca 2+ )-specific SFPBs by random insertion of calmodulin (CaM)-RS20 into miRFP680, a particularly bright near-infrared (NIR) FP based on a biliverdin (BV)-binding fluorescent protein. Starting from an miRFP680-based Ca 2+ biosensor prototype, we performed extensive directed evolution, including under BV-deficient conditions, to create highly optimized biosensors designated the NIR-GECO3 series. We have extensively characterized the NIR-GECO3 series and explored their utility for biological Ca 2+ imaging. The methods described in this work will serve to accelerate SFPB development and open avenues for further exploration and optimization of SFPBs across a spectrum of biological applications.

This report describes major pathomechanisms of disease in which the dysregulation of host inflammatory processes is a major factor, with cardiovascular disease (CVD) as a primary model, and reviews strategies for countermeasures based on synergistic interaction between various agents, including drugs and generally regarded as safe (GRAS) natural medical material (NMM), such as Ginkgo biloba , spice phytochemicals, and fruit seed flavonoids. The 15 well-defined CVD classes are explored with particular emphasis on the extent to which oxidative stressors and associated ischemia-reperfusion tissue injury contribute to major symptoms. The four major categories of pharmaceutical agents used for the prevention of and therapy for CVD: statins, beta blockers (β-blockers), blood thinners (anticoagulants), and aspirin, are presented along with their adverse effects. Analyses of major cellular and molecular features of drug- and NMM-mediated cardioprotective processes are provided in the context of their development for human clinical application. Future directions of the evolving research described here will be particularly focused on the characterization and manipulation of calcium- and calcineurin-mediated cascades of signaling from cell surface receptors on cardiovascular and immune cells to the nucleus, with the emergence of both protective and pathological epigenetic features that may be modulated by synergistically-acting combinations of drugs and phytochemicals in which phytochemicals interact with cells to promote signaling that reduces the effective dosage and thus (often) toxicity of drugs.

Ferroptosis is a newly defined programmed cell death pathway characterized by iron overload and lipid peroxidation. Increasing studies show that autophagy regulates testosterone synthesis and promotes ferroptosis. Testosterone is essential for sexual development and the maintenance of male characteristics. The deficiency of testosterone induced by cadmium (Cd) can severely affect male fertility. However, the underlying mechanism of testosterone reduction after Cd exposure remains blurry. In this study, we found that Cd affected iron homeostasis and elicited ferroptosis, ultimately reducing testosterone production. Mechanically, our findings revealed that Cd-induced ferroptosis depended upon the excessive activation of Heme oxygenase 1 (HMOX1) and the release of free iron from heme. Additionally, Cd exposure promoted autophagosome formation but blocked autophagosome-lysosome fusion, which attenuated the absorption of total cholesterol and triglycerides, further aggravating testosterone synthesis disorder. Collectively, Cd induced ferroptosis by iron homeostasis dysregulation, mediated by excessive activation of HMOX-1. The disruption of autophagy flow contributed to Cd-induced testicular dysfunction and attenuated testosterone synthesis. [Display omitted] • Cadmium attenuates testosterone synthesis. • Cadmium induces ferroptosis, characterized by iron overload and lipid peroxidation. • The overexpression of heme oxygenase 1, which releases Fe2+ from heme, participates in ferroptosis. • Cadmium leads to autophagic vesicles accumulation with the blockage of autophagosome-lysosome fusion. • The autophagy disruption affects the intake of cholesterol and testosterone biosynthesis. [ABSTRACT FROM AUTHOR]

Phycobiliproteins are colored, active molecules with potential use in different industries. They are the union of proteins and bilins (Chromophores). The primary source of phycobiliproteins is algae; however, the traditional algae culture has production restrictions. The production in bacterial models can be a more efficient alternative to produce these molecules. However, the lack of knowledge in some steps of the phycobiliprotein metabolic pathway limits this alternative. Porphyridium cruentum is a single cell red alga with a high phycobiliprotein content. Its protein sequences were the basis for phycobilin production in this study. In this study, we cloned and characterized enzymes presumably involved in the chromophore production of P. cruentum. Using sequences obtained from its transcriptome, we characterized two cDNA sequences predicted to code respectively for a ferredoxin-dependent bilin reductase and a bilin lyase-isomerase. We expressed these enzymes in Escherichia coli to obtain in vivo evidence of their enzymatic activity on the substrate biliverdin IXα. Lastly, we analyzed them using thin-layer chromatography, spectrophotometry, and fluorescence spectroscopy. These experiments provided evidence of bilin modification. The expressed bilin lyase-isomerase did not show significant activity over the biliverdin molecule. On the contrary, the expressed ferredoxin-dependent bilin reductase showed activity over the biliverdin. • We used data mining in the Porphyridium genus to search sequences involved in phycobilin synthesis. • Putative sequences for a ferredoxin-bilin reductase and a bilin lyase-isomerase were identified. • The sequences were successfully heterologously expressed in E. coli with a heme oxygenase. • Spectral properties of the cultures were analyzed. • The ferredoxin-bilin reductase showed in vivo activity toward biliverdin IXα. [ABSTRACT FROM AUTHOR]

Carbon monoxide (CO), a byproduct of heme catalyzed by heme oxygenase (HO), has been reported to exert antioxidant and anti-inflammatory actions, and to produce significant neuroprotective effects. The potential effects of CO and even HO on depressive-like behaviors are still poorly understood. Utilizing several approaches including adeno-associated virus (AAV)-mediated overexpression of HO-1, systemic CO-releasing molecules (CO-RMs), CO-rich saline or CO gas treatment procedures in combination with hydrogen peroxide (H2O2)-induced PC12 cell injury model, and lipopolysaccharide (LPS)-induced depression mouse model, the present study aimed to investigate the potential antidepressant- and anxiolytic-like effects of endogenous and exogenous CO administration in vivo and in vitro. The results of in vitro experiments showed that both CO-RM-3 and CO-RM-A1 pretreatment blocked H2O2-induced cellular injuries by increasing cell survival and decreasing cell apoptosis and necrosis. Similar to the effects of CO-RM-3 and CO-RM-A1 pretreatment, AAV-mediated HO-1 overexpression in the dorsal hippocampus produced significant antidepressant-like activities in mice under normal conditions. Further investigation showed that the CO gas treatment significantly blocked LPS-induced depressive- and anxiety-like behaviors in mice. Taken together, our results suggest that the activation of HO-1 and/or exogenous CO administration produces protective effects and exerts antidepressant- and anxiolytic-like effects. These data uncover a novel function of the HO-1/CO system that appears to be a promising therapeutic target for the treatment of depression and anxiety. [ABSTRACT FROM AUTHOR]

Heme oxygenase 1 (HO-1) is the key enzyme for heme catabolism and cytoprotection. Whereas HO-1 gene expression in response to various stresses has been investigated extensively, the precise mechanisms by which HO-1 gene expression is regulated by the HO-1 substrate heme remain elusive. To systematically examine whether stress-mediated induction and substrate-mediated induction of HO-1 utilize similar or distinct regulatory pathways, we developed an HO-1--DsRedknock- in reporter mouse in which the HO-1 gene is floxed by loxP sites and the DsRed gene has been inserted. Myeloid lineage-specific recombination of the floxed locus led to fluorescence derived from expression of the HO-1--DsRed fusion protein in peritoneal macrophages. We also challenged general recombination of the locus and generated mice harboring heterozygous recombinant alleles, which enabled us to monitor HO-1--DsRed expression in the whole body in vivo and ex vivo. HO-1 inducers upregulated HO-1--DsRed expression in myeloid lineage cells isolated from the mice. Notably, analyses of peritoneal macrophages from HO-1-- DsRed mice lacking NRF2, a major regulator of the oxidative/electrophilic stress response, led us to identify NRF2-dependent stress response-mediated HO-1 induction and NRF2-independent substrate-mediated HO-1 induction. Thus, the HO-1 gene is subjected to at least two distinct levels of regulation, and the available lines of evidence suggest that substrate induction in peritoneal macrophages is independent of CNC family-based regulation. [ABSTRACT FROM AUTHOR]

Marine mammals such as northern elephant seals (NES) routinely experience hypoxemia and ischemia-reperfusion events to many tissues during deep dives with no apparent adverse effects. Adaptations to diving include increased antioxidants and elevated oxygen storage capacity associated with high hemoprotein content in blood and muscle. The natural turnover of heme by heme oxygenase enzymes (encoded by HMOX1 and HMOX2) produces endogenous carbon monoxide (CO), which is present at high levels in NES blood and has been shown to have cytoprotective effects in laboratory systems exposed to hypoxia. To understand how pathways associated with endogenous CO production and signaling change across ontogeny in diving mammals, we measured muscle CO and baseline expression of 17 CO-related genes in skeletal muscle and whole blood of three age classes of NES. Muscle CO levels approached those of animals exposed to high exogenous CO, increased with age, and were significantly correlated with gene expression levels. Muscle expression of genes associated with CO production and antioxidant defenses (HMOX1 , BVR , GPX3 , PRDX1) increased with age and was highest in adult females, while that of genes associated with protection from lipid peroxidation (GPX4 , PRDX6 , PRDX1 , SIRT1) was highest in adult males. In contrast, muscle expression of mitochondrial biogenesis regulators (PGC1A , ESRRA , ESRRG) was highest in pups, while genes associated with inflammation (HMOX2 , NRF2 , IL1B) did not vary with age or sex. Blood expression of genes involved in regulation of inflammation (IL1B , NRF2 , BVR , IL10) was highest in pups, while HMOX1 , HMOX2 and pro-inflammatory markers (TLR4 , CCL4 , PRDX1 , TNFA) did not vary with age. We propose that ontogenetic upregulation of baseline HMOX1 expression in skeletal muscle of NES may, in part, underlie increases in CO levels and expression of genes encoding antioxidant enzymes. HMOX2 , in turn, may play a role in regulating inflammation related to ischemia and reperfusion in muscle and circulating immune cells. Our data suggest putative ontogenetic mechanisms that may enable phocid pups to transition to a deep-diving lifestyle, including high baseline expression of genes associated with mitochondrial biogenesis and immune system activation during postnatal development and increased expression of genes associated with protection from lipid peroxidation in adulthood. [ABSTRACT FROM AUTHOR]