Browsing by Subject "Reactive Oxygen Species"
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Item Open Access A prochelator activated by beta-secretase inhibits Abeta aggregation and suppresses copper-induced reactive oxygen species formation.(J Am Chem Soc, 2010-04-14) Folk, Drew S; Franz, Katherine JThe intersection of the amyloid cascade hypothesis and the implication of metal ions in Alzheimer's disease progression has sparked an interest in using metal-binding compounds as potential therapeutic agents. In the present work, we describe a prochelator SWH that is enzymatically activated by beta-secretase to produce a high affinity copper chelator CP. Because beta-secretase is responsible for the amyloidogenic processing of the amyloid precursor protein, this prochelator strategy imparts disease specificity toward copper chelation not possible with general metal chelators. Furthermore, once activated, CP efficiently sequesters copper from amyloid-beta, prevents and disassembles copper-induced amyloid-beta aggregation, and diminishes copper-promoted reactive oxygen species formation.Item Open Access Comprehensive pharmacokinetic studies and oral bioavailability of two Mn porphyrin-based SOD mimics, MnTE-2-PyP5+ and MnTnHex-2-PyP5+.(Free radical biology & medicine, 2013-05) Weitner, Tin; Kos, Ivan; Sheng, Huaxin; Tovmasyan, Artak; Reboucas, Julio S; Fan, Ping; Warner, David S; Vujaskovic, Zeljko; Batinic-Haberle, Ines; Spasojevic, IvanThe cationic, ortho Mn(III) N-alkylpyridylporphyrins (alkyl=ethyl, E, and n-hexyl, nHex) MnTE-2-PyP(5+) (AEOL10113, FBC-007) and MnTnHex-2-PyP(5+) have proven efficacious in numerous in vivo animal models of diseases having oxidative stress in common. The remarkable therapeutic efficacy observed is due to their: (1) ability to catalytically remove O2(•-) and ONOO(-) and other reactive species; (2) ability to modulate redox-based signaling pathways; (3) accumulation within critical cellular compartments, i.e., mitochondria; and (4) ability to cross the blood-brain barrier. The similar redox activities of both compounds are related to the similar electronic and electrostatic environments around the metal active sites, whereas their different bioavailabilities are presumably influenced by the differences in lipophilicity, bulkiness, and shape. Both porphyrins are water soluble, but MnTnHex-2-PyP(5+) is approximately 4 orders of magnitude more lipophilic than MnTE-2-PyP(5+), which should positively affect its ability to pass through biological membranes, making it more efficacious in vivo at lower doses. To gain insight into the in vivo tissue distribution of Mn porphyrins and its impact upon their therapeutic efficacy and mechanistic aspects of action, as well as to provide data that would ensure proper dosing regimens, we conducted comprehensive pharmacokinetic (PK) studies for 24h after single-dose drug administration. The porphyrins were administered intravenously (iv), intraperitoneally (ip), and via oral gavage at the following doses: 10mg/kg MnTE-2-PyP(5+) and 0.5 or 2mg/kg MnTnHex-2-PyP(5+). Drug levels in plasma and various organs (liver, kidney, spleen, heart, lung, brain) were determined and PK parameters calculated (Cmax, C24h, tmax, and AUC). Regardless of high water solubility and pentacationic charge of these Mn porphyrins, they are orally available. The oral availability (based on plasma AUCoral/AUCiv) is 23% for MnTE-2-PyP(5+) and 21% for MnTnHex-2-PyP(5+). Despite the fivefold lower dose administered, the AUC values for liver, heart, and spleen are higher for MnTnHex-2-PyP(5+) than for MnTE-2-PyP(5+) (and comparable for other organs), clearly demonstrating the better tissue penetration and tissue retention of the more lipophilic MnTnHex-2-PyP(5+).Item Open Access Copper signaling axis as a target for prostate cancer therapeutics.(Cancer Res, 2014-10-15) Safi, R; Nelson, ER; Chitneni, SK; Franz, KJ; George, DJ; Zalutsky, MR; McDonnell, DPPreviously published reports indicate that serum copper levels are elevated in patients with prostate cancer and that increased copper uptake can be used as a means to image prostate tumors. It is unclear, however, to what extent copper is required for prostate cancer cell function as we observed only modest effects of chelation strategies on the growth of these cells in vitro. With the goal of exploiting prostate cancer cell proclivity for copper uptake, we developed a "conditional lethal" screen to identify compounds whose cytotoxic actions were manifested in a copper-dependent manner. Emerging from this screen was a series of dithiocarbamates, which, when complexed with copper, induced reactive oxygen species-dependent apoptosis of malignant, but not normal, prostate cells. One of the dithiocarbamates identified, disulfiram (DSF), is an FDA-approved drug that has previously yielded disappointing results in clinical trials in patients with recurrent prostate cancer. Similarly, in our studies, DSF alone had a minimal effect on the growth of prostate cancer tumors when propagated as xenografts. However, when DSF was coadministered with copper, a very dramatic inhibition of tumor growth in models of hormone-sensitive and of castrate-resistant disease was observed. Furthermore, we determined that prostate cancer cells express high levels of CTR1, the primary copper transporter, and additional chaperones that are required to maintain intracellular copper homeostasis. The expression levels of most of these proteins are increased further upon treatment of androgen receptor (AR)-positive prostate cancer cell lines with androgens. Not surprisingly, robust CTR1-dependent uptake of copper into prostate cancer cells was observed, an activity that was accentuated by activation of AR. Given these data linking AR to intracellular copper uptake, we believe that dithiocarbamate/copper complexes are likely to be effective for the treatment of patients with prostate cancer whose disease is resistant to classical androgen ablation therapies.Item Open Access Delivery of an ectonucleotidase inhibitor with ROS-responsive nanoparticles overcomes adenosine-mediated cancer immunosuppression.(Science translational medicine, 2022-06) Mao, Chengqiong; Yeh, Stacy; Fu, Juan; Porosnicu, Mercedes; Thomas, Alexandra; Kucera, Gregory L; Votanopoulos, Konstantinos I; Tian, Shaomin; Ming, XinTumor evasion of immune destruction is associated with the production of immunosuppressive adenosine in the tumor microenvironment (TME). Anticancer therapies can trigger adenosine triphosphate (ATP) release from tumor cells, causing rapid formation of adenosine by the ectonucleotidases CD39 and CD73, thereafter exacerbating immunosuppression in the TME. The goal of this study was to develop an approach to facilitate cancer therapy-induced immunogenic cell death including ATP release and to limit ATP degradation into adenosine, in order to achieve durable antitumor immune response. Our approach was to construct reactive oxygen species (ROS)-producing nanoparticles that carry an ectonucleotidase inhibitor ARL67156 by electronic interaction and phenylboronic ester. Upon near-infrared irradiation, nanoparticle-produced ROS induced ATP release from MOC1 cancer cells in vitro and triggered the cleavage of phenylboronic ester, facilitating the release of ARL67156 from the nanoparticles. ARL67156 prevented conversion of ATP to adenosine and enhanced anticancer immunity in an MOC1-based coculture model. We tested this approach in mouse tumor models. Nanoparticle-based ROS-responsive drug delivery reprogramed the immunogenic landscape in tumors, eliciting tumor-specific T cell responses and tumor regression, conferring long-term survival in mouse models. We demonstrated that TME reprograming sets the stage for response to anti-programmed cell death protein 1 (PD1) immunotherapy, and the combination resulted in tumor regression in a 4T1 breast cancer mouse model that was resistant to PD1 blockade. Furthermore, our approach also induced immunological effects in patient-derived organotypic tumor spheroid model, suggesting potential translation of our nanoparticle approach for treating human cancers.Item Open Access Disrupting the vicious cycle created by NOX activation in sickle erythrocytes exposed to hypoxia/reoxygenation prevents adhesion and vasoocclusion.(Redox biology, 2019-07) MacKinney, Anson; Woska, Emily; Spasojevic, Ivan; Batinic-Haberle, Ines; Zennadi, RahimaIn sickle cell disease (SCD), recurrent painful vasoocclusive crisis are likely caused by repeated episodes of hypoxia and reoxygenation. The sickle erythrocyte (SSRBC) adhesion plays an active role in vasoocclusion. However, the effect of prolonged reoxygenation after hypoxic stress on the molecular mechanisms in SSRBCs involved in onset of episodic vasoocclusion remain unclear. Exposure of human SSRBCs to hypoxia followed by 2 h reoxygenation, increased reactive oxygen species (ROS) production. Using specific pharmacological inhibitors, we show that excess ROS production in both reticulocytes and mature SSRBCs is regulated by NADPH oxidases (NOXs), the mitogen-activated protein kinase (ERK1/2), and G-protein coupled-receptor kinase 2 (GRK2). Consequently, SSRBC ROS create an intracellular positive feedback loop with ERK1/2 and GRK2 to mediate SSRBC adhesion to endothelium in vitro, and vasoocclusion in a mouse model of vasoocclusion in vivo. Importantly, reducing ROS levels in SSRBCs with redox-active manganese (Mn) porphyrins, commonly known as mimics of superoxide dismutase (SOD), disrupted the cycle created by ROS by affecting NOX and GRK2 activities and ERK1/2 phosphorylation, thus abrogating RBC-endothelial interactions. Inhibition adhesion assays show that LW (ICAM-4, CD242) blood group glycoprotein and CD44 are the RBC adhesion molecules mediating endothelial binding. Conversely, hypoxia/reoxygenation of normal RBCs failed to activate this feedback loop, and adhesion. These findings provide novel insights into the pathophysiological significance of the deleterious cycle created by NOX-dependent ROS, GRK2 and ERK1/2 within SSRBCs activated by hypoxia/reoxygenation, and involved in SSRBC adhesion and vasoocclusion. Thus, this loop in SSRBCs, which can be disrupted by Mn porphyrins, likely drives the profound SCD vasculopathy, and may point to new therapeutic targets to prevent chronic vasoocclusive events.Item Open Access Drebrin regulates angiotensin II-induced aortic remodelling.(Cardiovascular research, 2018-11) Zhang, Lisheng; Wu, Jiao-Hui; Huang, Tai-Qin; Nepliouev, Igor; Brian, Leigh; Zhang, Zhushan; Wertman, Virginia; Rudemiller, Nathan P; McMahon, Timothy J; Shenoy, Sudha K; Miller, Francis J; Crowley, Steven D; Freedman, Neil J; Stiber, Jonathan AAims
The actin-binding protein Drebrin is up-regulated in response to arterial injury and reduces smooth muscle cell (SMC) migration and proliferation through its interaction with the actin cytoskeleton. We, therefore, tested the hypothesis that SMC Drebrin inhibits angiotensin II-induced remodelling of the proximal aorta.Methods and results
Angiotensin II was administered via osmotic minipumps at 1000 ng/kg/min continuously for 28 days in SM22-Cre+/Dbnflox/flox (SMC-Dbn-/-) and control mice. Blood pressure responses to angiotensin II were assessed by telemetry. After angiotensin II infusion, we assessed remodelling in the proximal ascending aorta by echocardiography and planimetry of histological cross sections. Although the degree of hypertension was equivalent in SMC-Dbn-/- and control mice, SMC-Dbn-/- mice nonetheless exhibited 60% more proximal aortic medial thickening and two-fold more outward aortic remodelling than control mice in response to angiotensin II. Proximal aortas demonstrated greater cellular proliferation and matrix deposition in SMC-Dbn-/- mice than in control mice, as evidenced by a higher prevalence of proliferating cell nuclear antigen-positive nuclei and higher levels of collagen I. Compared with control mouse aortas, SMC-Dbn-/- aortas demonstrated greater angiotensin II-induced NADPH oxidase activation and inflammation, evidenced by higher levels of Ser-536-phosphorylated NFκB p65 subunits and higher levels of vascular cell adhesion molecule-1, matrix metalloproteinase-9, and adventitial macrophages.Conclusions
We conclude that SMC Drebrin deficiency augments angiotensin II-induced inflammation and adverse aortic remodelling.Item Open Access Fiber type-specific nitric oxide protects oxidative myofibers against cachectic stimuli.(PLoS One, 2008-05-07) Yu, Zengli; Li, Ping; Zhang, Mei; Hannink, Mark; Stamler, Jonathan S; Yan, ZhenOxidative skeletal muscles are more resistant than glycolytic muscles to cachexia caused by chronic heart failure and other chronic diseases. The molecular mechanism for the protection associated with oxidative phenotype remains elusive. We hypothesized that differences in reactive oxygen species (ROS) and nitric oxide (NO) determine the fiber type susceptibility. Here, we show that intraperitoneal injection of endotoxin (lipopolysaccharide, LPS) in mice resulted in higher level of ROS and greater expression of muscle-specific E3 ubiqitin ligases, muscle atrophy F-box (MAFbx)/atrogin-1 and muscle RING finger-1 (MuRF1), in glycolytic white vastus lateralis muscle than in oxidative soleus muscle. By contrast, NO production, inducible NO synthase (iNos) and antioxidant gene expression were greatly enhanced in oxidative, but not in glycolytic muscles, suggesting that NO mediates protection against muscle wasting. NO donors enhanced iNos and antioxidant gene expression and blocked cytokine/endotoxin-induced MAFbx/atrogin-1 expression in cultured myoblasts and in skeletal muscle in vivo. Our studies reveal a novel protective mechanism in oxidative myofibers mediated by enhanced iNos and antioxidant gene expression and suggest a significant value of enhanced NO signaling as a new therapeutic strategy for cachexia.Item Open Access Heterogeneities in fullerene nanoparticle aggregates affecting reactivity, bioactivity, and transport.(ACS Nano, 2010-09-28) Chae, So-Ryong; Badireddy, Appala R; Farner Budarz, Jeffrey; Lin, Shihong; Xiao, Yao; Therezien, Mathieu; Wiesner, Mark RProperties of nanomaterial suspensions are typically summarized by average values for the purposes of characterizing these materials and interpreting experimental results. We show in this work that the heterogeneity in aqueous suspensions of fullerene C(60) aggregates (nC(60)) must be taken into account for the purposes of predicting nanomaterial transport, exposure, and biological activity. The production of reactive oxygen species (ROS), microbial inactivation, and the mobility of the aggregates of the nC(60) in a silicate porous medium all increased as suspensions were fractionated to enrich with smaller aggregates by progressive membrane filtration. These size-dependent differences are attributed to an increasing degree of hydroxylation of nC(60) aggregates with decreasing size. As the quantity and influence of these more reactive fractions may increase with time, experiments evaluating fullerene transport and toxicity end points must take into account the evolution and heterogeneity of fullerene suspensions.Item Open Access Interactions of oxygen radicals with airway epithelium.(Environ Health Perspect, 1994-12) Wright, DT; Cohn, LA; Li, H; Fischer, B; Li, CM; Adler, KBReactive oxygen species (ROS) have been implicated in the pathogenesis of numerous disease processes. Epithelial cells lining the respiratory airways are uniquely vulnerable regarding potential for oxidative damage due to their potential for exposure to both endogenous (e.g., mitochondrial respiration, phagocytic respiratory burst, cellular oxidases) and exogenous (e.g., air pollutants, xenobiotics, catalase negative organisms) oxidants. Airway epithelial cells use several nonenzymatic and enzymatic antioxidant mechanisms to protect against oxidative insult. Nonenzymatic defenses include certain vitamins and low molecular weight compounds such as thiols. The enzymes superoxide dismutase, catalase, and glutatione peroxidase are major sources of antioxidant protection. Other materials associated with airway epithelium such as mucus, epithelial lining fluid, and even the basement membrane/extracellular matrix may have protective actions as well. When the normal balance between oxidants and antioxidants is upset, oxidant stress ensues and subsequent epithelial cell alterations or damage may be a critical component in the pathogenesis of several respiratory diseases. Oxidant stress may profoundly alter lung physiology including pulmonary function (e.g., forced expiratory volumes, flow rates, and maximal inspiratory capacity), mucociliary activity, and airway reactivity. ROS may induce airway inflammation; the inflammatory process may serve as an additional source of ROS in airways and provoke the pathophysiologic responses described. On a more fundamental level, cellular mechanisms in the pathogenesis of ROS may involve activation of intracellular signaling enzymes including phospholipases and protein kinases stimulating the release of inflammatory lipids and cytokines. Respiratory epithelium may be intimately involved in defense against, and pathophysiologic changes invoked by, ROS.Item Open Access Linnemannia elongata (Mortierellaceae) stimulates Arabidopsis thaliana aerial growth and responses to auxin, ethylene, and reactive oxygen species.(PloS one, 2022-01) Vandepol, Natalie; Liber, Julian; Yocca, Alan; Matlock, Jason; Edger, Patrick; Bonito, GregoryHarnessing the plant microbiome has the potential to improve agricultural yields and protect plants against pathogens and/or abiotic stresses, while also relieving economic and environmental costs of crop production. While previous studies have gained valuable insights into the underlying genetics facilitating plant-fungal interactions, these have largely been skewed towards certain fungal clades (e.g. arbuscular mycorrhizal fungi). Several different phyla of fungi have been shown to positively impact plant growth rates, including Mortierellaceae fungi. However, the extent of the plant growth promotion (PGP) phenotype(s), their underlying mechanism(s), and the impact of bacterial endosymbionts on fungal-plant interactions remain poorly understood for Mortierellaceae. In this study, we focused on the symbiosis between soil fungus Linnemannia elongata (Mortierellaceae) and Arabidopsis thaliana (Brassicaceae), as both organisms have high-quality reference genomes and transcriptomes available, and their lifestyles and growth requirements are conducive to research conditions. Further, L. elongata can host bacterial endosymbionts related to Mollicutes and Burkholderia. The role of these endobacteria on facilitating fungal-plant associations, including potentially further promoting plant growth, remains completely unexplored. We measured Arabidopsis aerial growth at early and late life stages, seed production, and used mRNA sequencing to characterize differentially expressed plant genes in response to fungal inoculation with and without bacterial endosymbionts. We found that L. elongata improved aerial plant growth, seed mass and altered the plant transcriptome, including the upregulation of genes involved in plant hormones and "response to oxidative stress", "defense response to bacterium", and "defense response to fungus". Furthermore, the expression of genes in certain phytohormone biosynthetic pathways were found to be modified in plants treated with L. elongata. Notably, the presence of Mollicutes- or Burkholderia-related endosymbionts in Linnemannia did not impact the expression of genes in Arabidopsis or overall growth rates. Together, these results indicate that beneficial plant growth promotion and seed mass impacts of L. elongata on Arabidopsis are likely driven by plant hormone and defense transcription responses after plant-fungal contact, and that plant phenotypic and transcriptional responses are independent of whether the fungal symbiont is colonized by Mollicutes or Burkholderia-related endohyphal bacteria.Item Open Access Mitochondrial ROS cause motor deficits induced by synaptic inactivity: Implications for synapse pruning.(Redox biology, 2018-06) Sidlauskaite, Eva; Gibson, Jack W; Megson, Ian L; Whitfield, Philip D; Tovmasyan, Artak; Batinic-Haberle, Ines; Murphy, Michael P; Moult, Peter R; Cobley, James NDevelopmental synapse pruning refines burgeoning connectomes. The basic mechanisms of mitochondrial reactive oxygen species (ROS) production suggest they select inactive synapses for pruning: whether they do so is unknown. To begin to unravel whether mitochondrial ROS regulate pruning, we made the local consequences of neuromuscular junction (NMJ) pruning detectable as motor deficits by using disparate exogenous and endogenous models to induce synaptic inactivity en masse in developing Xenopus laevis tadpoles. We resolved whether: (1) synaptic inactivity increases mitochondrial ROS; and (2) chemically heterogeneous antioxidants rescue synaptic inactivity induced motor deficits. Regardless of whether it was achieved with muscle (α-bungarotoxin), nerve (α-latrotoxin) targeted neurotoxins or an endogenous pruning cue (SPARC), synaptic inactivity increased mitochondrial ROS in vivo. The manganese porphyrins MnTE-2-PyP5+ and/or MnTnBuOE-2-PyP5+ blocked mitochondrial ROS to significantly reduce neurotoxin and endogenous pruning cue induced motor deficits. Selectively inducing mitochondrial ROS-using mitochondria-targeted Paraquat (MitoPQ)-recapitulated synaptic inactivity induced motor deficits; which were significantly reduced by blocking mitochondrial ROS with MnTnBuOE-2-PyP5+. We unveil mitochondrial ROS as synaptic activity sentinels that regulate the phenotypical consequences of forced synaptic inactivity at the NMJ. Our novel results are relevant to pruning because synaptic inactivity is one of its defining features.Item Open Access Nrf2 inactivation enhances placental angiogenesis in a preeclampsia mouse model and improves maternal and fetal outcomes.(Science signaling, 2017-05-16) Nezu, Masahiro; Souma, Tomokazu; Yu, Lei; Sekine, Hiroki; Takahashi, Nobuyuki; Wei, Andrew Zu-Sern; Ito, Sadayoshi; Fukamizu, Akiyoshi; Zsengeller, Zsuzsanna K; Nakamura, Tomohiro; Hozawa, Atsushi; Karumanchi, S Ananth; Suzuki, Norio; Yamamoto, MasayukiPlacental activation of the renin-angiotensin system (RAS) plays a key role in the pathogenesis of preeclampsia. Reactive oxygen species (ROS) are thought to affect placental angiogenesis, which is critical for preventing preeclampsia pathology. We examined the role of ROS in preeclampsia by genetically modifying the Keap1-Nrf2 pathway, a cellular antioxidant defense system, in a mouse model of RAS-induced preeclampsia. Nrf2 deficiency would be expected to impair cellular antioxidant responses; however, Nrf2 deficiency in preeclamptic mice improved maternal and fetal survival, ameliorated intra-uterine growth retardation, and augmented oxidative DNA damage. Furthermore, the placentas of Nrf2-deficient mice had increased endothelial cell proliferation with dense vascular networks. In contrast, the placentas of preeclamptic mice with overactive Nrf2 showed repressed angiogenesis, which was associated with decreased expression of genes encoding angiogenic chemokines and cytokines. Our findings support the notion that ROS-mediated signaling is essential for maintaining placental angiogenesis in preeclampsia and may provide mechanistic insight into the negative results of clinical trials for antioxidants in preeclampsia.Item Open Access Oxidative Stress and Thrombosis during Aging: The Roles of Oxidative Stress in RBCs in Venous Thrombosis.(International journal of molecular sciences, 2020-06-15) Wang, Qinhong; Zennadi, RahimaMid-life stage adults are at higher risk of developing venous thrombosis (VT)/thromboembolism (VT/E). Aging is characterized by an overproduction of reactive oxygen species (ROS), which could evoke a series of physiological changes involved in thrombosis. Here, we focus on the critical role of ROS within the red blood cell (RBC) in initiating venous thrombosis during aging. Growing evidence has shifted our interest in the role of unjustifiably unvalued RBCs in blood coagulation. RBCs can be a major source of oxidative stress during aging, since RBC redox homeostasis is generally compromised due to the discrepancy between prooxidants and antioxidants. As a result, ROS accumulate within the RBC due to the constant endogenous hemoglobin (Hb) autoxidation and NADPH oxidase activation, and the uptake of extracellular ROS released by other cells in the circulation. The elevated RBC ROS level affects the RBC membrane structure and function, causing loss of membrane integrity, and decreased deformability. These changes impair RBC function in hemostasis and thrombosis, favoring a hypercoagulable state through enhanced RBC aggregation, RBC binding to endothelial cells affecting nitric oxide availability, RBC-induced platelet activation consequently modulating their activity, RBC interaction with and activation of coagulation factors, increased RBC phosphatidylserine exposure and release of microvesicles, accelerated aging and hemolysis. Thus, RBC oxidative stress during aging typifies an ultimate mechanism in system failure, which can affect major processes involved in the development of venous thrombosis in a variety of ways. The reevaluated concept of the critical role of RBC ROS in the activation of thrombotic events during aging will help identify potential targets for novel strategies to prevent/reduce the risk for VT/E or VT/E recurrences in mid-life stage adults.Item Open Access Oxidative stress during acetaminophen hepatotoxicity: Sources, pathophysiological role and therapeutic potential.(Redox biology, 2016-12) Du, Kuo; Ramachandran, Anup; Jaeschke, HartmutAcetaminophen (APAP) hepatotoxicity is characterized by an extensive oxidative stress. However, its source, pathophysiological role and possible therapeutic potential if targeted, have been controversially described. Earlier studies argued for cytochrome P450-generated reactive oxygen species (ROS) during APAP metabolism, which resulted in massive lipid peroxidation and subsequent liver injury. However, subsequent studies convincingly challenged this assumption and the current paradigm suggests that mitochondria are the main source of ROS, which impair mitochondrial function and are responsible for cell signaling resulting in cell death. Although immune cells can be a source of ROS in other models, no reliable evidence exists to support a role for immune cell-derived ROS in APAP hepatotoxicity. Recent studies suggest that mitochondrial targeted antioxidants can be viable therapeutic agents against hepatotoxicity induced by APAP overdose, and re-purposing existing drugs to target oxidative stress and other concurrent signaling events can be a promising strategy to increase its potential application in patients with APAP overdose.Item Open Access Pathogenic triad in COPD: oxidative stress, protease-antiprotease imbalance, and inflammation.(Int J Chron Obstruct Pulmon Dis, 2011) Fischer, Bernard M; Pavlisko, Elizabeth; Voynow, Judith APatients with chronic obstructive pulmonary disease (COPD) exhibit dominant features of chronic bronchitis, emphysema, and/or asthma, with a common phenotype of airflow obstruction. COPD pulmonary physiology reflects the sum of pathological changes in COPD, which can occur in large central airways, small peripheral airways, and the lung parenchyma. Quantitative or high-resolution computed tomography is used as a surrogate measure for assessment of disease progression. Different biological or molecular markers have been reported that reflect the mechanistic or pathogenic triad of inflammation, proteases, and oxidants and correspond to the different aspects of COPD histopathology. Similar to the pathogenic triad markers, genetic variations or polymorphisms have also been linked to COPD-associated inflammation, protease-antiprotease imbalance, and oxidative stress. Furthermore, in recent years, there have been reports identifying aging-associated mechanistic markers as downstream consequences of the pathogenic triad in the lungs from COPD patients. For this review, the authors have limited their discussion to a review of mechanistic markers and genetic variations and their association with COPD histopathology and disease status.Item Open Access Porcine endothelial cells cocultured with smooth muscle cells became procoagulant in vitro.(Tissue Eng Part A, 2010-06) Pang, Zhengyu; Niklason, Laura E; Truskey, George AEndothelial cell (EC) seeding represents a promising approach to provide a nonthrombogenic surface on vascular grafts. In this study, we used a porcine EC/smooth muscle cell (SMC) coculture model that was previously developed to examine the efficacy of EC seeding. Expression of tissue factor (TF), a primary initiator in the coagulation cascade, and TF activity were used as indicators of thrombogenicity. Using immunostaining, primary cultures of porcine EC showed a low level of TF expression, but a highly heterogeneous distribution pattern with 14% of ECs expressing TF. Quiescent primary cultures of porcine SMCs displayed a high level of TF expression and a uniform pattern of staining. When we used a two-stage amidolytic assay, TF activity of ECs cultured alone was very low, whereas that of SMCs was high. ECs cocultured with SMCs initially showed low TF activity, but TF activity of cocultures increased significantly 7-8 days after EC seeding. The increased TF activity was not due to the activation of nuclear factor kappa-B on ECs and SMCs, as immunostaining for p65 indicated that nuclear factor kappa-B was localized in the cytoplasm in an inactive form in both ECs and SMCs. Rather, increased TF activity appeared to be due to the elevated reactive oxygen species levels and contraction of the coculture, thereby compromising the integrity of EC monolayer and exposing TF on SMCs. The incubation of cocultures with N-acetyl-cysteine (2 mM), an antioxidant, inhibited contraction, suggesting involvement of reactive oxygen species in regulating the contraction. The results obtained from this study provide useful information for understanding thrombosis in tissue-engineered vascular grafts.Item Open Access Pyruvate dehydrogenase kinase supports macrophage NLRP3 inflammasome activation during acute inflammation.(Cell reports, 2023-01) Meyers, Allison K; Wang, Zhan; Han, Wenzheng; Zhao, Qingxia; Zabalawi, Manal; Duan, Likun; Liu, Juan; Zhang, Qianyi; Manne, Rajesh K; Lorenzo, Felipe; Quinn, Matthew A; Song, Qianqian; Fan, Daping; Lin, Hui-Kuan; Furdui, Cristina M; Locasale, Jason W; McCall, Charles E; Zhu, XueweiActivating the macrophage NLRP3 inflammasome can promote excessive inflammation with severe cell and tissue damage and organ dysfunction. Here, we show that pharmacological or genetic inhibition of pyruvate dehydrogenase kinase (PDHK) significantly attenuates NLRP3 inflammasome activation in murine and human macrophages and septic mice by lowering caspase-1 cleavage and interleukin-1β (IL-1β) secretion. Inhibiting PDHK reverses NLRP3 inflammasome-induced metabolic reprogramming, enhances autophagy, promotes mitochondrial fusion over fission, preserves crista ultrastructure, and attenuates mitochondrial reactive oxygen species (ROS) production. The suppressive effect of PDHK inhibition on the NLRP3 inflammasome is independent of its canonical role as a pyruvate dehydrogenase regulator. Our study suggests a non-canonical role of mitochondrial PDHK in promoting mitochondrial stress and supporting NLRP3 inflammasome activation during acute inflammation.Item Open Access Seasonal variations in air pollution particle-induced inflammatory mediator release and oxidative stress.(Environmental health perspectives, 2005-08) Becker, Susanne; Dailey, Lisa A; Soukup, Joleen M; Grambow, Steven C; Devlin, Robert B; Huang, Yuh-Chin THealth effects associated with particulate matter (PM) show seasonal variations. We hypothesized that these heterogeneous effects may be attributed partly to the differences in the elemental composition of PM. Normal human bronchial epithelial (NHBE) cells and alveolar macrophages (AMs) were exposed to equal mass of coarse [PM with aerodynamic diameter of 2.5-10 microm (PM(2.5-10)], fine (PM(2.5)), and ultrafine (PM(<0.1)) ambient PM from Chapel Hill, North Carolina, during October 2001 (fall) and January (winter), April (spring), and July (summer) 2002. Production of interleukin (IL)-8, IL-6, and reactive oxygen species (ROS) was measured. Coarse PM was more potent in inducing cytokines, but not ROSs, than was fine or ultrafine PM. In AMs, the October coarse PM was the most potent stimulator for IL-6 release, whereas the July PM consistently stimulated the highest ROS production measured by dichlorofluorescein acetate and dihydrorhodamine 123 (DHR). In NHBE cells, the January and the October PM were consistently the strongest stimulators for IL-8 and ROS, respectively. The July PM increased only ROS measured by DHR. PM had minimal effects on chemiluminescence. Principal-component analysis on elemental constituents of PM of all size fractions identified two factors, Cr/Al/Si/Ti/Fe/Cu and Zn/As/V/Ni/Pb/Se, with only the first factor correlating with IL-6/IL-8 release. Among the elements in the first factor, Fe and Si correlated with IL-6 release, whereas Cr correlated with IL-8 release. These positive correlations were confirmed in additional experiments with PM from all 12 months. These results indicate that elemental constituents of PM may in part account for the seasonal variations in PM-induced adverse health effects related to lung inflammation.Item Open Access Sickle erythrocytes target cytotoxics to hypoxic tumor microvessels and potentiate a tumoricidal response.(PLoS One, 2013) Terman, David S; Viglianti, Benjamin L; Zennadi, Rahima; Fels, Diane; Boruta, Richard J; Yuan, Hong; Dreher, Mathew R; Grant, Gerald; Rabbani, Zahid N; Moon, Ejung; Lan, Lan; Eble, Joseph; Cao, Yiting; Sorg, Brian; Ashcraft, Kathleen; Palmer, Greg; Telen, Marilyn J; Dewhirst, Mark WResistance of hypoxic solid tumor niches to chemotherapy and radiotherapy remains a major scientific challenge that calls for conceptually new approaches. Here we exploit a hitherto unrecognized ability of sickled erythrocytes (SSRBCs) but not normal RBCs (NLRBCs) to selectively target hypoxic tumor vascular microenviroment and induce diffuse vaso-occlusion. Within minutes after injection SSRBCs, but not NLRBCs, home and adhere to hypoxic 4T1 tumor vasculature with hemoglobin saturation levels at or below 10% that are distributed over 70% of the tumor space. The bound SSRBCs thereupon form microaggregates that obstruct/occlude up to 88% of tumor microvessels. Importantly, SSRBCs, but not normal RBCs, combined with exogenous prooxidant zinc protoporphyrin (ZnPP) induce a potent tumoricidal response via a mutual potentiating mechanism. In a clonogenic tumor cell survival assay, SSRBC surrogate hemin, along with H(2)O(2) and ZnPP demonstrate a similar mutual potentiation and tumoricidal effect. In contrast to existing treatments directed only to the hypoxic tumor cell, the present approach targets the hypoxic tumor vascular environment and induces injury to both tumor microvessels and tumor cells using intrinsic SSRBC-derived oxidants and locally generated ROS. Thus, the SSRBC appears to be a potent new tool for treatment of hypoxic solid tumors, which are notable for their resistance to existing cancer treatments.Item Open Access Skeletal muscle mitochondrial fragmentation and impaired bioenergetics from nutrient overload are prevented by carbon monoxide.(American journal of physiology. Cell physiology, 2020-10) Gasier, Heath G; Dohl, Jacob; Suliman, Hagir B; Piantadosi, Claude A; Yu, TianzhengNutrient excess increases skeletal muscle oxidant production and mitochondrial fragmentation that may result in impaired mitochondrial function, a hallmark of skeletal muscle insulin resistance. This led us to explore whether an endogenous gas molecule, carbon monoxide (CO), which is thought to prevent weight gain and metabolic dysfunction in mice consuming high-fat diets, alters mitochondrial morphology and respiration in C2C12 myoblasts exposed to high glucose (15.6 mM) and high fat (250 µM BSA-palmitate) (HGHF). Also, skeletal muscle mitochondrial morphology, distribution, respiration, and energy expenditure were examined in obese resistant (OR) and obese prone (OP) rats that consumed a high-fat and high-sucrose diet for 10 wk with or without intermittent low-dose inhaled CO and/or exercise training. In cells exposed to HGHF, superoxide production, mitochondrial membrane potential (ΔΨm), mitochondrial fission regulatory protein dynamin-related protein 1 (Drp1) and mitochondrial fragmentation increased, while mitochondrial respiratory capacity was reduced. CO decreased HGHF-induced superoxide production, Drp1 protein levels and mitochondrial fragmentation, maintained ΔΨm, and increased mitochondrial respiratory capacity. In comparison with lean OR rats, OP rats had smaller skeletal muscle mitochondria that contained disorganized cristae, a normal mitochondrial distribution, but reduced citrate synthase protein expression, normal respiratory responses, and a lower energy expenditure. The combination of inhaled CO and exercise produced the greatest effect on mitochondrial morphology, increasing ADP-stimulated respiration in the presence of pyruvate, and preventing a decline in resting energy expenditure. These data support a therapeutic role for CO and exercise in preserving mitochondrial morphology and respiration during metabolic overload.