Decreasing mitochondrial fission ameliorates HIF-1α-dependent pathological retinal angiogenesis

Angiogenesis plays a critical role in many pathological processes, including irreversible blindness in eye diseases such as retinopathy of prematurity. Endothelial mitochondria are dynamic organelles that undergo constant fusion and fission and are critical signalling hubs that modulate angiogenesis by coordinating reactive oxygen species (ROS) production and calcium signalling and metabolism. In this study, we investigated the role of mitochondrial dynamics in pathological retinal angiogenesis. We showed that treatment with vascular endothelial growth factor (VEGF; 20 ng/ml) induced mitochondrial fission in HUVECs by promoting the phosphorylation of dynamin-related protein 1 (DRP1). DRP1 knockdown or pretreatment with the DRP1 inhibitor Mdivi-1 (5 μM) blocked VEGF-induced cell migration, proliferation, and tube formation in HUVECs. We demonstrated that VEGF treatment increased mitochondrial ROS production in HUVECs, which was necessary for HIF-1α-dependent glycolysis, as well as proliferation, migration, and tube formation, and the inhibition of mitochondrial fission prevented VEGF-induced mitochondrial ROS production. In an oxygen-induced retinopathy (OIR) mouse model, we found that active DRP1 was highly expressed in endothelial cells in neovascular tufts. The administration of Mdivi-1 (10 mg·kg-1·d-1, i.p.) for three days from postnatal day (P) 13 until P15 significantly alleviated pathological angiogenesis in the retina. Our results suggest that targeting mitochondrial fission may be a therapeutic strategy for proliferative retinopathies and other diseases that are dependent on pathological angiogenesis.

Hepatic Ischemia-reperfusion Injury: Protective Approaches and Treatment

Ischemia and reperfusion damage to the liver is one of the major causes of hepatic dysfunction and liver failure after a liver transplant. The start of hepatic ischemia-reperfusion damage is linked to metabolic acidosis, Kupffer cells, neutrophils, excessive calcium, and changes in the permeability of the mitochondrial membrane. Hypoxia activates Kupffer cells, resulting in the production of reactive oxygen species (ROS). These ROS when accumulated, causes apoptosis and necrosis, as well as activate immune and inflammatory responses that involve many cells and signalling molecules. Numerous antioxidant compounds have been researched to lessen oxidative stress and thus serve as potential compounds to deal the ischemia-reperfusion damage. This article confers a deep understanding of the protective effects of some effective therapies, including hepatoprotective agents, attenuation of an increase in xanthine oxidase activity, and administration of antioxidants like N-acetylcysteine, superoxide dismutase (SOD), and ornithine.

Tris(2,3-dibromopropyl)Isocyanurate has an Effect on Inflammation Markers in Mouse Primary Astrocytes In vitro

Tris(2,3-dibromopropyl)isocyanurate (TBC or TDBP-TAZTO) is a new brominated flame retardant (BFR) used as a replacement of classic BFR, such as tetrabromobisphenol A. TBC is supposed to be safer than classic BFRs, but reports show that it may induce a similar toxic effect. Therefore, the aim of the present study was to determine the impact of TBC on the inflammation and activation of the apoptosis process in mouse cortical astrocytes in vitro. Our results have shown that TBC increases caspase-1 and caspase-3 activity in mouse astrocytes in vitro, which suggests inflammation-induced apoptosis. Further analyses have revealed that TBC indeed increases the level of inflammation markers, e.g. Cat, IL-1β and IL-1βR1 proteins, but decreases the level of proliferation marker protein Ki67. However, our study has demonstrated that TBC does not change the morphology of astrocytes and does not increase the number of apoptotic bodies - a well-established marker of late apoptosis. Moreover, the concentration of 50 µM TBC also increases caspase-3 activity with no formation of apoptotic bodies. However, since 10 and 50 µM TBC have never been detected in living organisms, we can assume that the compound is safe at the low concentrations that are detected.

NOX-2 Inhibitors may be Potential Drug Candidates for the Management of COVID-19 Complications

COVID-19 is an RNA virus that attacks the targeting organs, which express angiotensin-converting enzyme-2 (ACE-2), such as the lungs, heart, renal system, and gastrointestinal tract. The virus that enters the cell by endocytosis triggers ROS production within the confines of endosomes via a NOX-2 containing NADPH-oxidase. Various isoforms of NADPH oxidase are expressed in airways and alveolar epithelial cells, endothelial and vascular smooth muscle cells, and inflammatory cells, such as alveolar macrophages, monocytes, neutrophils, and T-lymphocytes. The key NOX isoform expressed in macrophages and neutrophils is the NOX-2 oxidase, whereas, in airways and alveolar epithelial cells, it appears to be NOX-1 and NOX-2. The respiratory RNA viruses induce NOX-2-mediated ROS production in the endosomes of alveolar macrophages. The mitochondrial and NADPH oxidase (NOX) generated ROS can enhance TGF-β signaling to promote fibrosis of the lungs. The endothelium-derived ROS and platelet-derived ROS, due to activation of the NADPH-oxidase enzyme, play a crucial role in platelet activation. It has been observed that NOX-2 is generally activated in COVID-19 patients. The post-COVID complications like pulmonary fibrosis and platelet aggregation may be due to the activation of NOX-2. NOX-2 inhibitors may be a useful drug candidate to prevent COVID-19 complications like pulmonary fibrosis and platelet aggregation.

Juglone Mediates Inflammatory Bowel Disease Through Inhibition of TLR-4/NF KappaB Pathway in Acetic Acid-induced Colitis in Rats

BACKGROUND

Juglone is a phenolic bioactive compound with antimicrobial, antitumour, antioxidant, and anti-inflammatory characteristics. Given its anti-inflammatory and antioxidant effects, it was selected for evaluation in the inflammatory bowel diseases (IBD) model.

OBJECTIVE

The current study was performed to evaluate the therapeutic impacts of the juglone in acetic acid-induced colitis in male Wistar rats.

METHODS

Juglone was extracted from Pterocarya fraxinifolia via maceration method. Colitis was induced in 36 male Wistar rats (n = 6), except in the sham group, 1 ml of acetic acid 4% was administered intrarectally. Twenty-four hours after induction of colitis, in 3 groups, juglone was administered orally (gavage) at 3 doses of 50, 100, and 150 mg/kg for 2 successive days (once a day). Other groups included the control group (only treated with acetic acid), sham group (normal saline), and standard group (Dexamethasone). To evaluate the inflammation sites, macroscopic and microscopic markers were assessed. The mRNA expression of interleukin (IL)-1β, and tumor necrosis factor-alpha (TNF)-α were assessed by real-time PCR, while myeloperoxidase (MPO) was measured spectrophotometrically. ELISA assay kits were used to determine the colonic levels of SOD, ROS, NF-κB, and TLR-4.

RESULTS

Macroscopic and microscopic assessments revealed that juglone significantly decreased colonic tissue damage and inflammation at 150 mg/kg. Juglone at 100, 150 mg/kg significantly decreased the TNF-α, MPO, and TLR-4 levels, as well as the SOD activity. All juglone-treated groups reduced the NF-κB levels compared to the control group (p < 0.001). The compound decreased the IL-1β, and ROS levels at the concentration of 150 mg/kg. Juglone attenuated colitis symptoms, reduced inflammation cytokines, declined neutrophil infiltration, and suppressed IL- 1β and TNF-α expressions in acetic acid-induced colitis rats. It may be proposed that juglone improved colitis in animal model through suppression of inflammatory parameters and downregulation of the NF-κB-TLR-4 pathway.

CONCLUSION

Juglone exhibited anti-inflammatory and antioxidant effects in the experimental colitis model and could be a therapeutic candidate for IBD. Juglone should be a subject for further animal and clinical trials in IBD models and for safety concerns.

Role of sperm apoptosis and oxidative stress in male infertility: A narrative review

Activation of caspase, externalization of phosphatidyl serine, change in the mitochondrial membrane potential, and DNA fragmentation are apoptosis markers found in human ejaculated spermatozoa. Also, reactive oxygen species (ROS) play a vital role in the different types of male infertility. In this review, data sources including Google Scholar, Scopus, PubMed, and Science Direct were searched for publications with no particular time restriction to get a holistic and comprehensive view of the research. Apoptosis regulates the male germ cells, correct function and development from the early embryonic stages of gonadal differentiation to fertilization. In addition to maintaining a reasonable ratio between the Sertoli and germ cells, apoptosis is one of the well-known quality control mechanisms in the testis. Also, high ROS levels cause a heightened and dysregulated apoptotic response. Apoptosis is one of the well-known mechanisms of quality control in the testis. Nevertheless, increased apoptosis may have adverse effects on sperm production. Recent studies have shown that ROS and the consequent oxidative stress play a crucial role in apoptosis. This review aims to assimilate and summarize recent findings on the apoptosis in male reproduction and fertility. Also, this review discusses the update on the role of ROS in normal sperm function to guide future research in this area.

Deletion of Mitochondrial Uncoupling Protein 2 Exacerbates Mitochondrial Damage in Mice Subjected to Cerebral Ischemia and Reperfusion Injury under both Normo- and Hyperglycemic Conditions

Deletion of mitochondrial uncoupling protein 2 (UCP2) has been shown to aggravate ischemic damage in the brain. However, the underlying mechanisms are not fully understood. The objective of this study is to explore the impact of homozygous UCP2 deletion (UCP2^-/-) on mitochondrial fission and fusion dynamic balance in ischemic mice under normo- and hyperglycemic conditions. UCP2^-/- and wildtype mice were subjected to a 60 min middle cerebral artery occlusion (MCAO) and allowed reperfusion for 6h, 24h and 72h. Our results demonstrated that deletion of UCP2 enlarged infarct volumes and increased numbers of cell death in both normo- and hyperglycemic ischemic mice compared with their wildtype counterparts subjected to the same duration of ischemia and reperfusion. The detrimental effects of UCP deletion were associated with increased ROS production, elevated mitochondrial fission markers Drp1 and Fis1 and suppressed fusion markers Opa1 and Mfn2 in UCP2^-/- mice. Electron microscopic study demonstrated a marked mitochondrial swolling after 6h of reperfusion in UCP2^-/- mice, contrasting to a mild mitochondrial swolling in wildtype ischemic animals. It is concluded that the exacerbating effects of UCP2^-/- on ischemic outcome in both normo- and hyperglycemic animals are associated with increased ROS production, disturbed mitochondrial dynamic balance towards fission and early damage to mitochondrial ultrastructure.

Liensinine inhibited gastric cancer cell growth through ROS generation and the PI3K/AKT pathway

Liensinine, an isoquinoline alkaloid extracted from the seed embryo of Nelumbo nucifera Gaertn, has been shown to exhibit various phrenological effects, including anti‑cancer activity. The aim of this study is to investigate the effects and mechanisms of liensinine in human gastric cancer cells. In this study, we found liensinine can significantly inhibit gastric cancer cell proliferation in vitro and in vivo. Liensinine inducedgastric cancer cell apoptosis by increasing cleaved PARP, caspased 3 and caspased 9. Moreover, liensinine induced cycle arrest by downregulatingcyclinD1/cyclin‑dependent kinase4 and phosphorylated protein kinase B. Furthermore, we found liensinine increases ROS levels and inhibits the PI3K/AKT pathway. These data suggested that liensinine might represent a novel and effective agent against gastric cancer.

Oxidative Stress and Cancer: The Role of Nrf2

Oxidative stress due to imbalance between ROS production and detoxification plays a pivotal role in determining cell fate. In response to the excessive ROS, apoptotic signaling pathway is activated to promote normal cell death. However, through deregulation of biomolecules, high amount of ROS promotes carcinogenesis in cells with defective signaling factors. In this line, NRF2 appears to be as a master regulator, which protects cells from oxidative and electrophilic stress. Nrf2 is an intracellular transcription factor that regulates the expression of a number of genes to encode anti-oxidative enzymes, detoxifying factors, anti-apoptotic proteins and drug transporters. Under normal condition, Nrf2 is commonly degraded in cytoplasm by interaction with Keap1 inhibitor as an adaptor for ubiquitination factors. However, high amount of ROS activates tyrosine kinases to dissociate Nrf2: Keap1 complex, nuclear import of Nrf2 and coordinated activation of cytoprotective gene expression. Nevertheless, deregulation of Nrf2 and/or Keap1 due to mutation and activated upstream oncogenes is associated with nuclear accumulation and constitutive activation of Nrf2 to protect cells from apoptosis and induce proliferation, metastasis and chemoresistance. Owning to the interplay of ROS and Nrf2 signaling pathways with carcinogenesis, Nrf2 modulation seems to be important in the personalization of cancer therapy.

Neutrophil Extracellular Traps as a Drug Target to Counteract Chronic and Acute Inflammation

Neutrophil extracellular traps (NET), extruded decondensated chromatin entangled with neutrophil proteases, have been first identified in neutrophils stimulated with bacteria or phorbol myristate acetate (PMA) via activation of NADPH oxidase and the generation of reactive oxygen species. Although the first findings demonstrated the beneficial role of NET formation by trapping the bacteria and limiting their dissemination, numerous studies in the recent decade revealed the multifunctional aspects of NET formation which manifests itself not only in the context of anti-microbial effect but also as a pathological trigger. Uncontrolled and exaggerated NET formation or inability to digest and remove NET have been reported in thrombosis, auto-immune diseases, cancer or even in infertility. Studies are ongoing to disclose the role of NET in different pathological situations and most importantly, NET regulation via compounds that either interfere with NET formation or target NET components such as DNA or neutrophil proteases. Although the final product of NET formation seems to be quite common i.e. DNA entangled with proteases, stimuli that induce NET have a wide range of varieties and the involved pathways are diverse too. Therefore, in every pathological condition, it is necessary to consider carefully the type of stimulus and the signaling pathways in order to target the disease more specifically. Here we briefly summarize some (out of many) NET triggers/pathways and discuss the potential interventions in the pathological situations.

In vitro and in vivo assessment of free radical scavenging and antioxidant activities of Veronica persica Poir

With the appearance of new disorders along with inability of some conventional therapies for the treatment of diseases without any side effects, the discovery of safe and efficient therapeutic agents is of utmost importance in the medical area. In this context, medicinal plants as promising therapeutic candidates can provide a reliable and efficient profile. Since free radicals are at the center of various disorder pathways, reducing their production or complete removal of these chemical species could be advantageous for prevention and treatment of many diseases. In this experiment, free radical scavenging and antioxidant activities of Veronica persica Poir., a known medicinal plant, were evaluated using in vitro and in vivo assays. Chemical characterization results showed a high phenolic content in the V. persica methanol extract. In addition, in vitro assays including DPPH radical-scavenging assay, nitric oxide-scavenging activity assay, hydrogen peroxide scavenging test and bleomycin-dependent DNA damage test revealed significant antioxidant power and radical scavenging capacity of this plant. In accordance, in vivo experiments showed inhibitory effects of the methanol extract on lipid peroxidation, a main cause of cell damage. Our findings revealed the promising potential of this plant in reducing free radicals through different pathways. Moreover, our data suggested a correlation between the high phenolic content of the V. persica extract and its free radical scavenging and antioxidant activities.

Oxidative Signaling Response to Cadmium Exposure

Changes in the intracellular thiol-disulfide balance are considered major determinants in the redox status/signaling of the cell. Cellular signaling is very sensitive to both exogenous and intracellular redox status and respond to many exogenous pro-oxidative or oxidative stresses. Redox status has dual effects on upstream signaling systems and downstream transcription factors. Redox signaling pathways use reactive oxygen species (ROS) to transfer signals from different sources to the nucleus to regulate such functions as growth, differentiation, proliferation, and apoptosis. Mitogen-activated protein kinases are activated by numerous cellular stresses and ligand-receptor bindings. An imbalance in the oxidant/antioxidant system, either resulting from excessive ROS/reactive nitrogen species production and/or antioxidant system impairment, leads to oxidative stress. Glutathione (GSH) is known to play a critical role in the cellular defense against unregulated oxidative stress in mammalian cells and involvement of large molecular antioxidants include classical antioxidant enzymes, such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). Cadmium (Cd), a potent toxic heavy metal, is a widespread environmental contaminant. It is known to cause renal dysfunction, hepatic toxicity, genotoxicity, and apoptotic effects depending on the dose, route, and duration of exposure. This review examines the signaling pathways and mechanisms of activation of transcription factors by Cd-induced oxidative stress thus representing an important basis for understanding the mechanisms of Cd effect on the cells.

Ferula gummosa gum induces apoptosis via ROS mechanism in human leukemic cells

Ferula species known for its oleo-resins that are recognized valuable industrial crops and food products. In this study, we examined the level of cellular oxidants, cytotoxicity, apoptosis and differentiation induced by oleo resin gum from Ferula gummosa (30-250 µg/mL), as well as Arsenic trioxide (50 µM, as positive control), in leukemic (NB4 and HL-60 cells) and normal polymorph nuclear cells during 72 h. Resazurin assay was used to determine cell viability following treatment with F. gummosa (30-250 µg/mL). Intracellular reactive oxygen species was measured by fluorimetry using carboxy 2', 7'-dichlorofluorescein diacetate. Apoptotic cells were evaluated using PI staining of DNA fragmentation by flow cytometry (sub-G1 peak). Differentiation of cells evaluated by Giemsa staining and Nitro Blue Tetrazolium reduction. F. gummosa showed a concentration-dependent suppression in cell survival with IC50 values of 41.8 µg/mL for HL60 and 59.2 µg/mL for NB4 cells after 72 h treatment. ROS formation and apoptotic cells were concentration-dependently increased following treatment with F. gummosa, similar to As2O3. F. gummosa did not induce differentiation of leukemic cells towards granulocytic pattern. The resin did not have toxic effect on PMN cells (&lt;800 µg/mL). In conclusion, the present study demonstrated that F. gummosa induced apoptosis through ROS mechanism on leukemic cells as a concentration and time dependent manner. The precise signaling pathway by which F. gummosa induce apoptosis needs further research.

The J-protein AtDjB1 is required for mitochondrial complex I activity and regulates growth and development through ROS-mediated auxin signalling

AtDjB1 is a mitochondria-located J-protein in Arabidopsis thaliana It is involved in the regulation of plant growth and development; however, the exact mechanisms remain to be determined. We performed comparison analyses of phenotypes, auxin signalling, redox status, mitochondrial structure and function using wild-type plants, AtDjB1 mutants, rescued AtDjB1 mutants by AtDjB1 or YUCCA2 (an auxin synthesis gene), and AtDjB1 overexpression plants. AtDjB1 mutants (atj1-1 or atj1-4) exhibited inhibition of growth and development and reductions in the level of IAA and the expression of YUCCA genes compared to wild-type plants. The introduction of AtDjB1 or YUCCA2 into atj1-1 largely rescued phenotypic defects and the IAA level, indicating that AtDjB1 probably regulates growth and development via auxin. Furthermore, atj1-1 plants displayed a significant reduction in amount/activity of mitochondrial complex I compared to wild-type plants; this resulted in the accumulation of reactive oxygen species (ROS). Moreover, exogenous H2O2 markedly inhibited the expression of YUCCA genes in wild-type plants. In contrast, the reducing agent ascorbate increased the expression of YUCCA genes and IAA level in atj1-1 plants, indicating that the low auxin level observed in atj1-1 was probably due to the high oxidation status. Overall, the data presented here suggest that AtDjB1 is required for mitochondrial complex I activity and regulates growth and development through ROS-mediated auxin signalling in Arabidopsis.

SCF E3 ligase PP2-B11 plays a positive role in response to salt stress in Arabidopsis

Skp1-Cullin-F-box (SCF) E3 ligases are essential to the post-translational regulation of many important factors involved in cellular signal transduction. In this study, we identified an F-box protein from Arabidopsis thaliana, AtPP2-B11, which was remarkably induced with increased duration of salt treatment in terms of both transcript and protein levels. Transgenic Arabidopsis plants overexpressing AtPP2-B11 exhibited obvious tolerance to high salinity, whereas the RNA interference line was more sensitive to salt stress than wild-type plants. Isobaric tag for relative and absolute quantification analysis revealed that 4311 differentially expressed proteins were regulated by AtPP2-B11 under salt stress. AtPP2-B11 could upregulate the expression of annexin1 (AnnAt1) and function as a molecular link between salt stress and reactive oxygen species accumulation in Arabidopsis. Moreover, AtPP2-B11 influenced the expression of Na(+) homeostasis genes under salt stress, and the AtPP2-B11 overexpressing lines exhibited lower Na(+) accumulation. These results suggest that AtPP2-B11 functions as a positive regulator in response to salt stress in Arabidopsis.

An Arabidopsis soluble chloroplast proteomic analysis reveals the participation of the Executer pathway in response to increased light conditions

The Executer1 and Executer2 proteins have a fundamental role in the signalling pathway mediated by singlet oxygen in chloroplast; nonetheless, not much is known yet about their specific activity and features. Herein, we have followed a differential-expression proteomics approach to analyse the impact of Executer on the soluble chloroplast protein abundance in Arabidopsis. Because singlet oxygen plays a significant role in signalling the oxidative response of plants to light, our analysis also included the soluble chloroplast proteome of plants exposed to a moderate light intensity in the time frame of hours. A number of light- and genotype-responsive proteins were detected, and mass-spectrometry identification showed changes in abundance of several photosynthesis- and carbon metabolism-related proteins as well as proteins involved in plastid mRNA processing. Our results support the participation of the Executer proteins in signalling and control of chloroplast metabolism, and in the regulation of plant response to environmental changes.

Life and death under salt stress: same players, different timing?

Salinity does not only stress plants but also challenges human life and the economy by posing severe constraints upon agriculture. To understand salt adaptation strategies of plants, it is central to extend agricultural production to salt-affected soils. Despite high impact and intensive research, it has been difficult to dissect the plant responses to salt stress and to define the decisive key factors for the outcome of salinity signalling. To connect the rapidly accumulating data from different systems, treatments, and organization levels (whole-plant, cellular, and molecular), and to identify the appropriate correlations among them, a clear conceptual framework is required. Similar to other stress responses, the molecular nature of the signals evoked after the onset of salt stress seems to be general, as with that observed in response to many other stimuli, and should not be considered to confer specificity per se. The focus of the current review is therefore on the temporal patterns of signals conveyed by molecules such as Ca(2+), H(+), reactive oxygen species, abscisic acid, and jasmonate. We propose that the outcome of the salinity response (adaptation versus cell death) depends on the timing with which these signals appear and disappear. In this context, the often-neglected non-selective cation channels are relevant. We also propose that constraining a given signal is as important as its induction, as it is the temporal competence of signalling (signal on demand) that confers specificity.

Life-history Constraints on the Mechanisms that Control the Rate of ROS Production

The quest to understand why and how we age has led to numerous lines of investigation that have gradually converged to consider mitochondrial metabolism as a major player. During mitochondrial respiration a small and variable amount of the consumed oxygen is converted to reactive species of oxygen (ROS). For many years, these ROS have been perceived as harmful by-products of respiration. However, evidence from recent years indicates that ROS fulfill important roles as cellular messengers. Results obtained using model organisms suggest that ROS-dependent signalling may even activate beneficial cellular stress responses, which eventually may lead to increased lifespan. Nevertheless, when an overload of ROS cannot be properly disposed of, its accumulation generates oxidative stress, which plays a major part in the ageing process. Comparative studies about the rates of ROS production and oxidative damage accumulation, have led to the idea that the lower rate of mitochondrial oxygen radical generation of long-lived animals with respect to that of their short-lived counterpart, could be a primary cause of their slow ageing rate. A hitherto largely under-appreciated alternative view is that such lower rate of ROS production, rather than a cause may be a consequence of the metabolic constraints imposed for the large body sizes that accompany high lifespans. To help understanding the logical underpinning of this rather heterodox view, herein I review the current literature regarding the mechanisms of ROS formation, with particular emphasis on evolutionary aspects.

The Effects of Aging on Indices of Oxidative Stress and Apoptosis in the Female Fischer 344/Nnia X Brown Norway/BiNia Rat Heart

Oxidative-nitrosative stress may play a role in age-associated cardiovascular disease as implied by recent studies.However, limited research has been conducted using aged female rodent models. In this study, we examined hearts obtained from 6-, 26-, and 30-month old female Fischer 344/Nnia x Brown Norway/BiNia (F344xBN) rats in order to examine how aging affects levels of cardiac oxidative-nitrosative stress and apoptosis. Oxidative (superoxide anion and 4-HNE) and nitrosative (protein nitrosylation) stress markers were increased 180 ± 17 %, 110 ± 3 %, and 14 ± 2 %, respectively in 30-month hearts compared to the hearts of 6-month female rats. Coincident with these changes in oxidative-nitrosative stress, aging was also found to be associated with increases in the number of Tdt-mediated dUTP nick labeling (TUNEL)-positive cardiomyocytes, alterations in the Bax/Bcl-2 ratio, and elevated cleavage of caspase-3. Regression analysis demonstrates significant correlation in the age-associated changes markers of oxidative–nitrosative stress with changes in apoptotic signaling. The findings from this descriptive study imply that age-associated increases in mitochondrial-mediated apoptosis may be associated with the increase in oxidative-nitrosative stress in the aging F344xBN female heart.

Hepatocyte growth factor protects against isoniazid/rifampicin-induced oxidative liver damage

The worldwide increment of multidrug- and extensively drug-resistant tuberculosis has emphasized the importance of looking for new options in therapeutics. Long-time usage or higher doses of isoniazid and rifampicin have been considered for the treatment of multidrug-resistant tuberculosis; however, the risk of liver failure is proportionally increased. Hepatocyte growth factor (HGF) is a multitask growth factor that stimulates both antiapoptotic and antioxidant responses that counteract the toxic effects of drug metabolism in the liver. The present work was focused to address the antioxidant and antiapoptotic effects of HGF on isoniazid- and rifampicin-induced hepatotoxicity. BALB/c mice were subjected to rifampicin (150mg/kg, intragavage [ig]) plus isoniazid (75mg/kg, ig) for 7 days. Increments in alanine aminotransferase activity, steatosis, apoptosis, and oxidative stress markers were found in animals. Recombinant HGF (iv) prevented all the harmful effects by increasing the activation of Erk1/2 and PKCδ signaling pathways and glutathione (GSH) synthesis. Furthermore, inhibition of endogenous HGF with anti-HGF antibody (iv) enhanced the isoniazid- and rifampicin-induced oxidative stress damage and decreased the GSH content, aggravating liver damage. In conclusion, HGF demonstrated to be a good protective factor against antituberculosis drug-induced hepatotoxicity and could be considered a good adjuvant factor for the use of high doses of or the reintroduction of these antituberculosis drugs.

Dimerumic acid inhibits SW620 cell invasion by attenuating H₂O₂-mediated MMP-7 expression via JNK/C-Jun and ERK/C-Fos activation in an AP-1-dependent manner

Reactive oxygen species (ROS) such as hydrogen peroxide (H₂O₂) in the tumor microenvironment play important roles in tumor invasion and metastasis. Recently, ROS have been reported to cause a significant increase in the production and expression of matrix metalloproteinase (MMP)-7, which is closely correlated with metastatic colorectal cancer. The present study was undertaken to evaluate the scavenging activity of dimerumic acid (DMA) for H₂O₂ isolated from Monascus-fermented rice to investigate the inhibitory effects of DMA on the invasive potential of SW620 human colon cancer cells, and to explore the mechanisms underlying both these phenomena. Our results showed that increased MMP-7 expression due to H₂O₂ exposure was mediated by activation of mitogen-activated protein kinases (MAPKs) such as Jun N-terminal kinase (JNK), extracellular-regulated kinase (ERK), and p38 kinase. DMA pretreatment suppressed activation of H₂O₂-mediated MAPK pathways and cell invasion. Moreover, H₂O₂-triggered MMP-7 production was demonstrated via JNK/c-Jun and ERK/c-Fos activation in an activating protein 1 (AP-1)-dependent manner. Taken together, these results suggest that DMA suppresses H₂O₂-induced cell invasion by inhibiting AP-1-mediated MMP-7 gene transcription via the JNK/c-Jun and ERK/c-Fos signaling pathways in SW620 human colon cancer cells. Our data suggest that DMA may be useful in minimizing the development of colorectal metastasis. In the future, DMA supplementation may be a beneficial antioxidant to enhance surgical outcomes.