A Blood-Triggered Adhesive Hydrogel Loaded with Reactive Oxygen Species-Responsive Liposomes for the Treatment of Acute Kidney Injury.

Increased seminal reactive oxygen species levels in patients with varicoceles correlate with varicocele grade but not with testis size

The effects of short-term (ST; 10days) and long-term (LT; 30days) intermittent hypoxia (IH) on blood pressure (BP), breathing and carotid body (CB) chemosensory reflex were examined in adult rats. ST- and LT-IH treated rats exhibited hypertension, irregular breathing with apnoea and augmented the CB chemosensory reflex, with all these responses becoming normalized during recovery from ST- but not from LT-IH. The persistent cardiorespiratory responses to LT-IH were associated with elevated reactive oxygen species (ROS) levels in the CB and adrenal medulla, which were a result of DNA methylation-dependent suppression of genes encoding anti-oxidant enzymes (AOEs). Treating rats with decitabine either during LT-IH or during recovery from LT-IH prevented DNA methylation of AOE genes, normalized the expression of AOE genes and ROS levels, reversed the heightened CB chemosensory reflex and hypertension, and also stabilized breathing. Rodents exposed to chronic intermittent hypoxia (IH), simulating blood O2 saturation profiles during obstructive sleep apnoea (OSA), have been shown to exhibit a heightened carotid body (CB) chemosensory reflex and hypertension. CB chemosensory reflex activation also results in unstable breathing with apnoeas. However, the effect of chronic IH on breathing is not known. In the present study, we examined the effects of chronic IH on breathing along with blood pressure (BP) and assessed whether the autonomic responses are normalized after recovery from chronic IH. Studies were performed on adult, male, Sprague-Dawley rats exposed to either short-term (ST; 10days) or long-term (LT, 30days) IH. Rats exposed to either ST- or LT-IH exhibited hypertension, irregular breathing with apnoeas, an augmented CB chemosensory reflex as indicated by elevated CB neural activity and plasma catecholamine levels, and elevated reactive oxygen species (ROS) levels in the CB and adrenal medulla (AM). All these effects were normalized after recovery from ST-IH but not from LT-IH. Analysis of the molecular mechanisms underlying the persistent effects of LT-IH revealed increased DNA methylation of genes encoding anti-oxidant enzymes (AOEs). Treatment with decitabine, a DNA methylation inhibitor, either during LT-IH or during recovery from LT-IH, prevented DNA methylation, normalized the expression of AOE genes, ROS levels, CB chemosensory reflex and BP, and also stabilized breathing. These results suggest that persistent cardiorespiratory abnormalities caused by LT-IH are mediated by epigenetic re-programming of the redox state in the CB chemosensory reflex pathway.

The induction of senescence, an irreversible growth arrest, in cancer cells is regarded as a mean to halt tumor progression. The phytoalexin resveratrol (RV) is known to possess a variety of cancer-preventive, -therapeutic, and -chemosensitizing properties. We report here that chronic treatment with RV in a subapoptotic concentration induces senescence-like growth arrest in tumor cells. In contrast to the widely accepted antioxidant property of RV, we demonstrate that one causative stimulus for senescence induction by chronic RV is an increased level of reactive oxygen species (ROS). The ROS formed upon RV exposure include hydrogen peroxide and superoxide and originate largely from mitochondria. Consistently, co-incubation with the antioxidant N-acetyl cysteine interfered with RV-mediated reactivation of the senescence program. Molecular mediators on the way from increased ROS levels to the observed growth arrest include p38 MAPK, p53, and p21. Moreover, we provide evidence that RV-initiated replication stress, apparent by activation of the ataxia telangiectasia-mutated kinase pathway, is associated with increased ROS levels and senescence induction. This is the first report linking cell cycle effects with a pro-oxidant and pro-senescent effect of RV in cancer cells.

Higher levels of reactive oxygen species are associated with anergy in chronic lymphocytic leukemia2][3] As in other cells, mitochondria appear to be the main source of ROS and CLL cells have an increased mitochondrial mass compared to that of normal B cells. 2,4Higher levels of ROS confer increased sensitivity to induction of apoptosis by agents which further enhance ROS and it may be possible to exploit this as the basis for new treatments. 1,2,5]5,6 Analyses have mainly been performed on samples from patients with more advanced disease and, in that setting, prior therapy appeared to be a major determinant of ROS levels. 3,5,6This may reflect a direct effect of drugs on ROS production, perhaps linked to accumulation of mitochondrial DNA damage. 6However, a recent study demonstrated variable ROS levels in cells from untreated patients 2 indicating an influence of other factors.The B-cell receptor (BCR) is now recognized as a key determinant of variable behavior of CLL 7 and is a target for therapeutic attack.Antigen engagement appears to be iterative, with the outcome being either proliferation or anergy, a balance likely to influence disease outcome. 7,8Anergy

Dyskerin pseudouridine synthase 1 (DKC1) is a conserved gene encoding the RNA-binding protein dyskerin, which is an essential component of the telomerase holoenzyme. DKC1 up-regulation is frequently observed in many different human cancers including hepatocellular carcinoma (HCC); however, its regulatory mechanisms remain unclear. Thus, we investigated the regulatory mechanism of DKC1 in HCC progression. We found that protein-disulfide isomerase-associated 3 (PDIA3) interacted with the DKC1 regulatory DNA in HCC cells but not in HCC cells with elevated reactive oxygen species (ROS) levels, using liquid chromatographic-tandem mass spectrometric analysis after isolating the DKC1 regulatory region binding proteins. PDIA3 repressed DKC1 expression in HCC cells by recognizing the G-quadruplex DNA at the DKC1 location. However, oxidative modification of PDIA3 induced by ROS redistributed this protein into the cytosolic regions, which stimulated DKC1 expression. We also identified Met338 in PDIA3 as the oxidatively modified residue and validated the effect of oxidative modification using an ectopic expression system, a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 knock-in system, and a xenograft mouse model. We observed that oxidatively modified PDIA3 promoted DKC1-mediated malignancy and survival of HCC cells in vitro and in vivo. HCC tissues showed a positive association with ROS, cytoplasmic PDIA3, and nuclear DKC1 levels. HCC patients with high PDIA3 protein and DKC1 mRNA levels also displayed reduced recurrence-free survival rates. Cumulatively, the results showed that cytoplasmic PDIA3 activity could be essential in raising DKC1 expression in HCC progression and predicting poor prognoses in HCC patients. Conclusion: Our study indicates that the elevated ROS levels in HCC modulate cytoplasmic PDIA3 levels, resulting in HCC cell survival through DKC1 up-regulation.

Acute myeloid leukemia (AML) cells harbor elevated levels of reactive oxygen species (ROS), which promote cell proliferation and cause oxidative stress. Therefore, the inhibition of ROS formation or elevation beyond a toxic level have been considered as therapeutic strategies. ROS elevation has recently been linked to enhanced NADPH oxidase 4 (NOX4) activity. Therefore, the compound Setanaxib (GKT137831), a clinically advanced ROS-modulating substance, which has initially been identified as a NOX1/4 inhibitor, was tested for its inhibitory activity on AML cells. Setanaxib showed antiproliferative activity as single compound, and strongly enhanced the cytotoxic action of anthracyclines such as daunorubicin in vitro. Setanaxib attenuated disease in a mouse model of FLT3-ITD driven myeloproliferation in vivo. Setanaxib did not significantly inhibit FLT3-ITD signaling, including FLT3 autophosphorylation, activation of STAT5, AKT, or extracellular signal regulated kinase 1 and 2 (ERK1/2). Surprisingly, the effects of Setanaxib on cell proliferation appeared to be independent of the presence of NOX4 and were not associated with ROS quenching. Instead, Setanaxib caused elevation of ROS levels in the AML cells and importantly, enhanced anthracycline-induced ROS formation, which may contribute to the combined effects. Further assessment of Setanaxib as potential enhancer of cytotoxic AML therapy appears warranted.

53BP1 regulates the self-renewal ability of neural stem/progenitor cells through modulating mitochondrial homeostasis

The role of hypoxia-inducible factor (HIF)-1 in pancreatic β-cell response to intermittent hypoxia (IH) was examined. Studies were performed on adult wild-type (WT), HIF-1α heterozygous (HET), β-cell-specific HIF-1-/- mice and mouse insulinoma (MIN6) cells exposed to IH patterned after blood O2 profiles during obstructive sleep apnea. WT mice treated with IH showed insulin resistance, and pancreatic β-cell dysfunction manifested as augmented basal insulin secretion, and impaired glucose-stimulated insulin secretion and these effects were absent in HIF-1α HET mice. IH increased HIF-1α expression and elevated reactive oxygen species (ROS) levels in β-cells of WT mice. The elevated ROS levels were due to transcriptional upregulation of NADPH oxidase (NOX)-4 mRNA, protein and enzymatic activity, and these responses were absent in HIF-1α HET mice as well as in β-HIF-1-/- mice. IH-evoked β-cell responses were absent in adult WT mice treated with digoxin, an inhibitor of HIF-1α. MIN6 cells treated with in vitro IH showed enhanced basal insulin release and elevated HIF-1α protein expression, and these effects were abolished with genetic silencing of HIF-1α. IH increased NOX4 mRNA, protein, and enzyme activity in MIN6 cells and disruption of NOX4 function by siRNA or scavenging H2O2 with polyethylene glycol catalase blocked IH-evoked enhanced basal insulin secretion. These results demonstrate that HIF-1-mediated transcriptional activation of NOX4 and the ensuing increase in H2O2 contribute to IH-induced pancreatic β-cell dysfunction.

Aging of different avian cultured cells: Lack of ROS-induced damage and quality control mechanisms

Successful implantation requires a fine-tuned dialog between the invading embryo and the maternal endometrium. Recently, we discovered that premature senescence of endometrial stromal cells (EnSC) might mediate improper decidual transformation of endometrial tissue and impair endometrial-blastocyst interaction. Here, we show that senescent EnSC are characterized by elevated intracellular reactive oxygen species (ROS) levels that originate from mitochondrial dysfunction and insufficient antioxidant defense. Decidualization of senescent EnSC is defective and is accompanied by the elevated intracellular and mitochondrial ROS levels. Antioxidant defense during decidualization is significantly less efficient in senescent EnSC compared to healthy ones. Senescent EnSC secrete increased amounts of ROS into the extracellular space. Elevated ROS released by senescent EnSC shift the redox balance and induce DNA damage in the neighboring trophoblast-like cells. In an in vitro implantation model, we observed impaired spreading of blastocyst-like spheroids into a monolayer of decidualizing senescent EnSC, which could be compensated by pretreatment of the senescent cells with the antioxidant, Tempol. Hence, we propose a possible mechanism that might be responsible, at least in part, for the defective embryo implantation realized via ROS transmitting from senescent EnSC to trophoblast cells. Such transmission results in the accumulation of ROS and subsequent DNA damage in trophoblastic cells, which might lead to improper migration and invasion of an embryo. In light of these findings, the application of antioxidants prior to implantation might be a promising strategy to improve implantation efficiency.

Background: Thyroid disorders are associated with elevated reactive oxygen species (ROS) levels that trigger apoptosis. Nevertheless, the precise connection between ROS levels and apoptotic markers in thyroid dysfunction remains unclear. Aim: To explore the relationship between ROS levels and intrinsic apoptotic (IA) markers in thyroid homogenates derived from hypothyroidism and hyperthyroidism mouse models. Methods: Eighteen male Wistar rats, each weighing 240 ± 10 g, were allocated to three groups of six rats. Hypothyroidism and hyperthyroidism were induced over 8 weeks using 0.05% Propylthiouracil (PTU) and 0.0012% Levothyroxine (L-Thy), respectively. T3, T4, and thyroid-stimulating hormone (TSH) levels were measured, and thyroid size and body weights were recorded. The levels of ROS markers (MDA, GSH, SOD-1, CAT, and GPX) and IA markers (Bax, Bcl-2, and caspase-3) were assessed in tissue homogenates. Results: A gradual weight loss was observed in the hyperthyroidism group compared with the control group. The hypothyroid model showed elevated MDA levels and cleaved caspase-3, as well as a higher Bax/Bcl-2 ratio, whereas GSH, SOD-1, CAT, GPX, and Bcl-2 levels were lower than those in the control group (P < 0.05). In contrast, no changes were observed in the hyperthyroid models. Thyroid hormone levels are inversely correlated with ROS and positively correlated with antioxidant levels. Conclusion: Hypothyroidism models exhibited increased oxidative stress and pro-apoptotic markers, suggesting the initiation of apoptosis and cellular damage. Conversely, the hyperthyroid models showed no such changes.

Mdm2 Is Required for Survival of Hematopoietic Stem Cells/Progenitors via Dampening of ROS-Induced p53 Activity

Background: Pulmonary contusion represents a significant cause of respiratory morbidity following blunt chest trauma, characterized by complex pathophysiological mechanisms involving oxidative stress and inflammatory cascades. The temporal relationship between arterial oxygen partial pressure (PaO2), reactive oxygen species (ROS), interleukin-6 (IL-6), and histopathological changes including alveolar oedema, alveolar haemorrhage, and leukocyte infiltration remains incompletely understood. Objective: To investigate the temporal progression of oxidative stress markers, inflammatory cytokines, and histopathological alterations in an experimental pulmonary contusion model, with emphasis on the relationship between PaO2, ROS, IL-6, and pulmonary structural damage. Methods: Twenty-seven male Sprague-Dawley rats (8-12 weeks, 180-250g) were randomly allocated to three groups: control, 1-hour post-contusion, and 48-hour post-contusion. Pulmonary contusion was induced using a standardized blunt trauma model involving a 500-gram weight dropped from 50 cm height. Arterial oxygen partial pressure (PaO2) was measured using blood gas analysis and expressed in millimeters of mercury (mmHg). Blood samples were analyzed immediately after collection using a calibrated blood gas analyzer (ABL90 FLEX, Radiometer, Denmark) maintained at 37°C. Reactive oxygen species (ROS) levels were quantified using enzyme-linked immunosorbent assay (ELISA) and expressed as relative fluorescence units per milligram of protein (RFU/mg protein). Lung tissue samples were homogenized in phosphate-buffered saline (PBS) containing protease inhibitors, and protein concentration was determined using the Bradford assay. ROS levels were measured using the OxiSelect™ ROS Assay Kit (Cell Biolabs, Inc., San Diego, CA, USA) according to the manufacturer's protocol. Interleukin-6 (IL-6) concentrations were quantified using enzyme-linked immunosorbent assay (ELISA) and expressed in picograms per milliliter (pg/mL). Lung tissue homogenates were prepared as described above, and IL-6 levels were measured using the Rat IL-6 ELISA Kit (R&D Systems, Minneapolis, MN, USA). Histopathological examination was performed using hematoxylin-eosin staining to assess alveolar oedema, alveolar haemorrhage, and leukocyte infiltration. Statistical analysis employed one-way ANOVA with Tukey HSD post-hoc test for normally distributed data (PaO2, ROS, IL-6) and Kruskal-Wallis test with Mann-Whitney U post-hoc analysis for non-normally distributed data (histopathological parameters). Results: Arterial oxygen partial pressure demonstrated progressive deterioration from control levels (85.73 ± SD) to 76.89 ± SD at 1 hour post-contusion (p < 0.1) and 70.61 ± SD at 48 hours post-contusion (overall p < 0.001), indicating compromised gas exchange function. Reactive oxygen species levels showed significant elevation from baseline (874.0 ± SD) to 1314 ± SD at 1 hour and 1464 ± SD at 48 hours post-injury (overall p < 0.1), demonstrating sustained oxidative stress. Interleukin-6 concentrations increased dramatically from control values (7.378 ± SD) to 32.56 ± SD at 1 hour post-contusion (p < 0.1) and remained elevated at 32 ± SD at 48 hours (overall p < 0.1), indicating robust inflammatory activation. Alveolar oedema scores increased progressively from control (0.667 ± SD) to 1.9 ± SD at 1 hour (p < 0.1) and 2.78 ± SD at 48 hours post-contusion (overall p < 0.001). Alveolar haemorrhage demonstrated significant elevation from control levels (0.889 ± SD) to 2.3 ± SD at 1 hour (p < 0.05) and 2.78 ± SD at 48 hours post-contusion (overall p < 0.001). Leukocyte infiltration exhibited gradual increase from control (1.11 ± SD) through 1.8 ± SD at 1 hour to 2.33 ± SD at 48 hours post-contusion (overall p < 0.01). Conclusions: Pulmonary contusion triggers a biphasic pathophysiological response characterized by immediate oxidative stress and inflammatory activation followed by sustained tissue damage. The progressive decline in arterial oxygen partial pressure correlates with elevated ROS and IL-6 levels, accompanied by persistent alveolar oedema, alveolar haemorrhage, and leukocyte infiltration. These findings demonstrate the critical role of oxidative stress and inflammatory mediators in the pathogenesis of pulmonary contusion and provide valuable insights for developing targeted therapeutic interventions.

This study aims to investigate the synergistic effects of AB-Flu nanodrugs and exercise intervention on enhancing the antitumor effects in melanoma by improving the hypoxic tumor microenvironment (TME). The focus is on evaluating how this combination influences reactive oxygen species (ROS) levels, inhibition of melanoma in vivo. An intact B16F10 melanoma mouse model was established, and mice were divided into four groups: control, AB-Flu treatment, exercise intervention, and combination therapy (AB-Flu + exercise). AB-Flu nanodrug was administered intraperitoneally, while exercise was facilitated by a weighted swimming intervention. Tumor growth, tumor hypoxia, ROS levels, and apoptosis were analyzed through tumor volume measurements, histological staining, and ROS detection assays. The antitumor effects of different treatments were compared. The combination therapy group showed the most significant tumor inhibition efficacy with tumor growth inhibition rates of 56%, compared to 30% for the AB-Flu monotherapy group and 41% for the exercise group. Additionally, tumor tissues from the combination group exhibited significantly lower levels of hypoxia and enhanced tumor cell apoptosis. ROS levels were substantially higher in the combination therapy group compared to other groups, indicating that the combination of AB-Flu and exercise synergistically elevated ROS production, which may contribute to increased tumor cell apoptosis. No significant toxicity was observed in major organs. The combination of AB-Flu nanodrugs and exercise intervention significantly enhances the antitumor effects in melanoma by improving the hypoxic TME, elevating ROS levels, and promoting apoptosis in tumor cells. This strategy may offer a potential approach for melanoma therapy.

Pancreatic ductal adenocarcinoma (PDAC) is the third-leading cause of cancer-related mortalities in the Western world and continues to be a major unresolvable health problem at the start of the 21st century. Resistance to the currently available treatment options has led to development of new approaches, such as personalized medicine and immunotherapy. However, new therapeutic strategies based on the unique molecular biology and physiology of pancreatic cancer hold the greatest promise. Glutathione S-transferase pi 1 (GSTP1) is a key detoxification enzyme which metabolizes xenobiotic compounds and byproducts of cellular metabolism. GSTP1 is overexpressed in many tumors, particularly ovarian, non-small cell lung, breast, colon, and pancreas. Moreover, GSTP1 is overexpressed in drug-resistant cancer cell lines. The reasons for increased expression ratios compared to normal tissues or wild-type cell lines are not well understood. To investigate the role of GSTP1 in PDAC pathogenicity, we generated two knockdown lines of GSTP1 in metabolically diverse PDAC cells. We showed that GSTP1 knockdown impairs the growth and proliferation of PDAC cells. Additionally, GSTP1 knockdown cells exhibit elevated reactive oxygen species (ROS) levels and a prolonged G0/G1 phase of the cell cycle. Intrigued by these results, we next examined whether pharmacological inhibition with a selective GSTP1 inhibitor, Ezatiostat (TLK199), also impaired PDAC pathogenicity. Ezatiostat is a small molecule drug and is novel glutathione analog, which selectively binds and inhibits GSTP1. Ezatiostat treatment in PDAC cells recapitulated the proliferation impairments observed with genetic inactivation of GSTP1 and elevated ROS levels. Orthotopic implantation of GSTP1 knockdown cells in athymic nude mice resulted in reduced tumor weight and volume compared to the control. The growth trajectory of the tumors was monitored via Vevo-3100 ultrasound imaging system. Our preliminary data indicate enhanced sensitivity of glycolytic cancer cells towards an ROS-inducing agent and a GSTP1 inhibitor, piperlongumine (PL). Interestingly, we have found PL is less cytotoxic to cells with reduced GSTP1 levels, indicating that PL primarily works by inhibiting GSTP1 activity. Together, these data suggest that GSTP1 knockdown and inhibition impairs the growth and survival of phenotypically diverse PDAC cells in vitro and in vivo. Moreover, GSTP1 knockdown results in elevated ROS levels and an extended G0/G1 phase of the cell cycle. With these data, we propose that GSTP1 is a novel therapeutic target for PDAC. Citation Format: Rahul Raj Singh, Katie M. Reindl. GSTP1 knockdown and inhibition impairs pancreatic ductal adenocarcinoma (PDAC) growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 764.