Involvement Of Reactive Oxygen Species Research Articles

Attenuation of Endoplasmic Reticulum Stress Enhances Carvacrol-Induced Apoptosis in Osteosarcoma Cell Lines.

Carvacrol is a monoterpenoid phenol that has excellent antimicrobial, antiviral, and anti-inflammatory activities. It can also improve wound healing. However, few studies have explored its antitumor effect on osteosarcoma. In this report, we tried to determine the potential efficacy of carvacrol against osteosarcoma cell lines. Our data revealed that carvacrol exposure inhibited the proliferation of osteosarcoma HOS and U-2 OS cells. In addition, carvacrol exposure enhanced the levels of cleaved PARP and caspase 3 and increased annexin V-positive cells, indicating that carvacrol exposure triggers apoptosis in osteosarcoma cell lines. Furthermore, the levels of reactive oxygen species (ROS) were enhanced after carvacrol exposure and cotreatment with NAC, the ROS scavenger, decreased the levels of cleaved PARP and caspase 3, suggesting the involvement of ROS in carvacrol-induced apoptosis. Importantly, we found that carvacrol exposure triggered several protein expressions related to endoplasmic reticulum (ER) stress, including GRP78/Bip, IRE1a, PERK, and CHOP, in HOS and U-2 OS cells, indicating that carvacrol exposure could result in ER stress in these cell lines. Cotreatment with the ER stress inhibitor 4-PBA increased the levels of cleaved PARP and caspase 3 and further suppressed cellular proliferation in carvacrol-exposed osteosarcoma cell lines. Overall, the results indicate that induced ER stress can protect cells from apoptosis, but increased ROS contributes to apoptosis in carvacrol-treated cells. In this report, we first demonstrate the role of ER stress in carvacrol-induced apoptosis and suggest that ER stress could be targeted to enhance the antitumor activity of carvacrol in osteosarcoma cell lines.

Role of Oxidative Stress in Pathophysiological Progression of Schizophrenia

Background: Oxidative stress (OS) is a chief contributing factor to the pathological advancement of Schizophrenia (SCZ). In recent years, OS has emerged as an important aspect in SCZ research and provides abundant opportunities and expectations for a better understanding of its pathophysiology, which may lead to novel treatment strategies. Introduction: The increased OS and formation of reactive oxygen species (ROS) leads to damage to cellular macromolecules. The excessive OS is associated with several physiological processes, such as dysfunction of mitochondria and neuroglia, inflammation, underactive Nmethyl- D-aspartate (NMDA) receptors, and the abnormalities of fast-spiking gammaaminobutyric acid (GABA) interneurons. Methods: The methods adopted for the study are mainly based on the secondary search through a systemic literature review. The role of various anti-oxidants, including vitamins, is discussed in the reduction of SCZ. Results: Various preclinical and clinical studies suggest the involvement of OS and ROS in the progression of the disease. Recent human trials have shown the treatment with antioxidants to be effective in ameliorating symptoms and delaying the progression of SCZ pathology. The studies have demonstrated that innate and dietary antioxidants exert beneficial effects by reducing the severity of positive symptoms (PS) and/or negative symptoms (NS) of SCZ. Conclusion: The present review critically evaluates the effect of antioxidants and highlights the role of OS in SCZ.

Ramie leaf Extract Alleviates Bone Loss in Ovariectomized Rats-The Involvement of ROS and Its Associated Signalings.

Ramie leaf (Boehmeria nivea L.) has been traditionally used to treat gynecological and bone-related disorders. This study aims to evaluate the effect of Ramie leaf extracts (RLE) against osteoporosis in ovariectomized (OVX) rats. Female SD rats aged seven weeks were randomly assigned into five OVX and a sham-operated (sham) group. OVX subgroups include OVX, vehicle-treated OVX group; E2, OVX with 100 μg/kg 17β-estradiol; and RLE 0.25, 0.5, and 1, OVX rats treated with 0.25, 0.5, and 1 g/kg/day RLE, respectively. Two weeks into the bilateral ovariectomy, all the rats were orally administered with or without RLE daily for 12 weeks. OVX rats administered with RLE showed higher bone density, relatively low tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and lower reactive oxygen species (ROS) within bone tissues compared to vehicle-treated OVX rats. Furthermore, supplementation of RLE improved bone mineral density (BMD) and bone microstructure in the total femur. RLE prevented RANKL-induced osteoclast differentiation and expression of osteoclastogenesis-related genes such as Cal-R, MMP-9, cathepsin K, and TRAP in RANKL-induced RAW264.7 cells. Moreover, RLE administration lowered the intracellular ROS levels by reducing NADPH oxidase 1 (NOX-1) and 4-hydroxynonenal (4HNE). These results suggest that RLE alleviates bone mass loss in the OVX rats by inhibiting osteoclastogenesis, where reduced ROS and its associated signalings were involved.

Redox Status of Erythrocytes as an Important Factor in Eryptosis and Erythronecroptosis.

Overall, reactive oxygen species (ROS) signalling significantly contributes to initiation and mo-dulation of multiple regulated cell death (RCD) pathways. Lately, more information has become available about RCD modalities of erythrocytes, including the role of ROS. ROS accumulation has therefore been increasingly recognized as a critical factor involved in eryptosis (apoptosis of erythrocytes) and erythro-necroptosis (necroptosis of erythrocytes). Eryptosis is a Ca2+-dependent apoptosis-like RCD of erythrocytes that occurs in response to oxidative stress, hyperosmolarity, ATP depletion, and a wide range of xenobiotics. Moreover, eryptosis seems to be involved in the pathogenesis of multiple human diseases and pathological processes. Several studies have reported that erythrocytes can also undergo necroptosis, a lytic RIPK1/RIPK3/MLKL-mediated RCD. As an example, erythronecroptosis can occur in response to CD59-specific pore-forming toxins. We have systematically summarized available studies regarding the involvement of ROS and oxidative stress in these two distinct RCDs of erythrocytes. We have focused specifically on cellular signalling pathways involved in ROS-mediated cell death decisions in erythrocytes. Furthermore, we have summarized dysregulation of related erythrocytic antioxidant defence systems. The general concept of the ROS role in eryptotic and necroptotic cell death pathways in erythrocytes seems to be established. However, further studies are required to uncover the complex role of ROS in the crosstalk and interplay between the survival and RCDs of erythrocytes.

Natural Reno-Protective Agents against Cyclosporine A-Induced Nephrotoxicity: An Overview.

CA (cyclosporine A) is a powerful immunosuppressing agent that is commonly utilized for treating various autoimmune illnesses and in transplantation surgery. However, its usage has been significantly restricted because of its unwanted effects, including nephrotoxicity. The pathophysiology of CA-induced kidney injury involves inflammation, apoptosis, tubular injury, oxidative stress, and vascular injury. Despite the fact that exact mechanism accountable for CA's effects is inadequately understood, ROS (reactive oxygen species) involvement has been widely proposed. At present, there are no efficient methods or drugs for treating CA-caused kidney damage. It is noteworthy that diverse natural products have been investigated both in vivo and in-vitro for their possible preventive potential in CA-produced nephrotoxicity. Various extracts and natural metabolites have been found to possess a remarkable potential for restoring CA-produced renal damage and oxidative stress alterations via their anti-apoptosis, anti-inflammatory, and antioxidative potentials. The present article reviews the reported studies that assess the protective capacity of natural products, as well as dietary regimens, in relation to CA-induced nephrotoxicity. Thus, the present study presents novel ideas for designing and developing more efficient prophylactic or remedial strategies versus CA passive influences.

Peroxisome-Mediated Reactive Oxygen Species Signals Modulate Programmed Cell Death in Plants.

Peroxisomes are a class of simple organelles that play an important role in plant reactive oxygen species (ROS) metabolism. Experimental evidence reveals the involvement of ROS in programmed cell death (PCD) in plants. Plant PCD is crucial for the regulation of plant growth, development and environmental stress resistance. However, it is unclear whether the ROS originated from peroxisomes participated in cellular PCD. Enzymes involved in the peroxisomal ROS metabolic pathways are key mediators to figure out the relationship between peroxisome-derived ROS and PCD. Here, we summarize the peroxisomal ROS generation and scavenging pathways and explain how peroxisome-derived ROS participate in PCD based on recent progress in the functional study of enzymes related to peroxisomal ROS generation or scavenging. We aimed to elucidate the role of the peroxisomal ROS regulatory system in cellular PCD to show its potential in terms of accurate PCD regulation, which contribute to environmental stress resistance.

ROS function as an inducer of autophagy to promote granulocyte proliferation in Pacific oyster Crassostrea gigas

Hematopoiesis is the biological process to generate new blood cells in the living body and reactive oxygen species (ROS) contribute significantly to the regulation of haematopoietic cell homeostasis. In the present study, the involvement of ROS in the proliferation of haemocytes was examined in Pacific oyster Crassostrea gigas. The ROS content in haemocytes increased significantly after lipopolysaccharide (LPS) treatment, but decreased after the treatment with antioxidant N-Acetyl-L-cysteine (NAC, a scavenger of ROS). The percentage of 5-ethynyl-2′-deoxyuridine labeled (EdU+) granulocytes in total haemocytes significantly increased at 12 h (4.12-fold, p < 0.001) and 24 h (2.36-fold, p < 0.001) after LPS treatment, while decreased at 12 h (0.26-fold, p < 0.001) and 24 h (0.61-fold, p < 0.05) after NAC treatment, respectively. Meanwhile, the percentage of haemocytes with autophagosome positive signals significantly increased at 12 h (1.17-fold, p < 0.01) and 24 h (1.19-fold, p < 0.05) after LPS treatment, but significantly reduced at 12 h (0.41-fold, p < 0.001) and 24 h (0.28-fold, p < 0.001) after the NAC treatment, respectively. After ammonium chloride (NH4Cl) treatment, the percentage of haemocytes with autophagosome and EdU+ granulocytes significantly increased at 12 h, which was 1.27-fold (p < 0.01) and 1.70-fold (p < 0.01) of control group, respectively. These results collectively suggested that ROS produced after LPS treatment could act as an inducer for autophagy and involved in regulating the proliferation of some granulocytes in C. gigas.

Flow Cytometric Analysis of Oxidative Stress in Escherichia coli B Strains Deficient in Genes of the Antioxidant Defence.

The detection of reactive oxygen species (ROS) and the analysis of oxidative stress are frequent applications of functional flow cytometry. Identifying and quantifying the ROS species generated during oxidative stress are crucial steps for the investigation of molecular mechanisms underlying stress responses. Currently, there is a wide availability of fluorogenic substrates for such purposes, but limitations in their specificity and sensitivity may affect the accuracy of the analysis. The aim of our work was to validate a new experimental model based in different strains of Escherichia coli B deficient in key genes for antioxidant defense, namely oxyR, sodA and sodB. We applied this model to systematically assess issues of specificity in fluorescent probes and the involvement of different ROS in a bacterial model of oxidative stress, as the probes can react with a variety of oxidants and free radical species. Our results confirm the higher sensitivity and specificity of the fluorescent probe mitochondrial peroxy yellow 1 (MitoPY1) for the detection of H2O2, and its very low capacity for organic hydroperoxides, thus extending MitoPY1′s specificity for H2O2 in mammalian cells to a bacterial model. On the contrary, the fluorescent probe 2′,7′-dichlorodihydrofluorescein diacetate (H2DCF-DA) is more sensitive to organic peroxides than to H2O2, confirming the lack of selectivity of H2DCF-DA to H2O2. Treatment with organic peroxides and H2O2 suggests a superoxide-independent oxidation of the fluorescent probe Hydroethidine (HE). We found a positive correlation between the lipophilicity of the peroxides and their toxicity to E. coli, suggesting greater quantitative importance of the peroxidative effects on the bacterial membrane and/or greater efficiency of the protection systems against the intracellular effects of H2O2 than against the membrane oxidative stress induced by organic peroxides. Altogether, our results may aid in preventing or minimizing experimental errors and providing recommendations for the proper design of cytometric studies of oxidative stress, in accordance with current recommendations and guidelines.

Role of the succinate pathway in the electrophysiological properties of right atria in a persistent atrial fibrillation sheep model

Atrial fibrillation (AF) is the most sustained arrhythmia and increases morbidity and mortality. However, development and maintenance of AF is a still poorly understood process. Metabolic remodelling could induce transition from paroxysmal to persistent AF. Succinate levels are increased in AF patients indicating a potential role for metabolic remodelling. To assess the impact of the succinate pathway on the electrophysiological properties of right atria (RA) in persistent AF sheep model. Optical experiments were performed in ex vivo RA from a burst pacing AF sheep model. RA were perfused by Tyrode solution with glucose (5.6 mM), subsequently replaced by succinate (10 mM) to increase mitochondrial reactive oxygen species (ROS) production which are known to modulate excitation-contraction coupling (ECC) and study metabolic remodelling. An activator of the succinate β-adrenergic receptor (GPR91), cis-epoxysuccinic acid (300 μM), was used to study the GPR91 involvement in atrial electrophysiology and AF. Action potential duration at 80% of repolarization (APD80) were assessed from 2 to 5 Hz pacing frequency and during sinus rhythm (SR). We used an S1S2 pacing protocol to determine effective refractory period (ERP) and a burst pacing protocol (30 Hz) to assess ex vivo AF vulnerability. Finally, an organ donation program allowed us to investigate these properties in a human RA from an AF patient. During succinate perfusion SR is decreased in Sham (1,5 vs 1,2 Hz; P = 0,03), AF (1,5 vs 1 Hz; P = 0,003) and resistant (1,3 vs 1 Hz; P = 0,01) sheep, ERP is increased in AF sheep (184 vs 344 ms; P = 0,0007) and APD80 is increased in Sham (217 vs 264 ms; P = 0,0004) and AF sheep (195 vs 275 ms; P = 0,003). We also observed an increase in amplitude alternans which can induce re-entries and therefore be pro-arrhythmic. These results seems to be confirmed on human AF RA by increasing APD80 (257 vs 309 ms), ERP (260 vs 330 ms) and spontaneous arrhythmias. GPR91 activation led to a slowing of SR (1,7 vs 1,3 Hz; P = 0,03), a shortening of APD80 (200 vs 170 ms; P = 0,007) and an increase in spontaneous arrhythmias. A dysregulation of ECC could explain our results consistently with the ROS involvement and metabolic remodelling in AF. For the first time, we also demonstrated that GPR91 pathway is involved in atrial electrophysiology and could be involved in AF mechanisms.

Reactive oxygen species in photosystem II: relevance for oxidative signaling.

Reactive oxygen species (ROS) are formed in photosystem II (PSII) under various types of abiotic and biotic stresses. It is considered that ROS play a role in chloroplast-to-nucleus retrograde signaling, which changes the nuclear gene expression. However, as ROS lifetime and diffusion are restricted due to the high reactivity towards biomolecules (lipids, pigments, and proteins) and the spatial specificity of signal transduction is low, it is not entirely clear how ROS might transduce signal from the chloroplasts to the nucleus. Biomolecule oxidation was formerly connected solely with damage; nevertheless, the evidence appears that oxidatively modified lipids and pigments are be involved in chloroplast-to-nucleus retrograde signaling due to their long diffusion distance. Moreover, oxidatively modified proteins show high spatial specificity; however, their role in signal transduction from chloroplasts to the nucleus has not been proven yet. The review attempts to summarize and evaluate the evidence for the involvement of ROS in oxidative signaling in PSII.

Local and systemic responses conferring acclimation of Brassica napus roots to low phosphorus conditions.

Due to the non-uniform distribution of inorganic phosphate (Pi) in the soil, plants modify their root architecture to improve acquisition of this nutrient. In this study, a split-root system was employed to assess the nature of local and systemic signals that modulate root architecture of Brassica napus grown with non-uniform Pi availability. Lateral root (LR) growth was regulated systemically by non-uniform Pi distribution, by increasing the second-order LR (2°LR) density in compartments with high Pi supply but decreasing it in compartments with low Pi availability. Transcriptomic profiling identified groups of genes regulated, both locally and systemically, by Pi starvation. The number of systemically induced genes was greater than the number of genes locally induced, and included genes related to abscisic acid (ABA) and jasmonic acid (JA) signalling pathways, reactive oxygen species (ROS) metabolism, sucrose, and starch metabolism. Physiological studies confirmed the involvement of ABA, JA, sugars, and ROS in the systemic Pi starvation response. Our results reveal the mechanistic basis of local and systemic responses of B. napus to Pi starvation and provide new insights into the molecular and physiological basis of root plasticity.

Cadmium enhances root hair elongation through reactive oxygen species in Arabidopsis

We previously reported that Arabidopsis shows enhanced root hair density and length in response to cadmium (Cd). To understand how Cd stimulates root hair elongation, we examined the role of reactive oxygen species (ROS) and root hair elongation-related genes in root hair elongation/tip growth. In response to Cd, Arabidopsis displayed enhanced length and ROS levels in the root hairs, indicating ROS involvement. Furthermore, in response to Cd, ROS generation mutants, including root hair defective 2 ( rhd2/rbohc ), rbohh , rbohj , per1 , per44 and per73, which have shorter root hairs because of impaired ROS generation, also showed increased root hair length and ROS levels, suggesting the involvement of these genes in ROS production in Cd-induced root hair elongation. Supporting the participation of ROS, N-acetyl- L -cysteine (ROS scavenger) treatment reduced root hair elongation and ROS levels. Additionally, the expression of proline-rich extension-like receptor kinase (PERK)5 , PERK8, and root hair-specific 10 ( RHS10 ) , which are negative regulators of root hair elongation, was reduced by Cd and ROS (H 2 O 2 ). Furthermore, the expression of expansin A7 ( EXPA7 ) and expansin A18 ( EXPA18 ), which are involved in root hair elongation, was remarkably induced by Cd and H 2 O 2 in elongating root hairs and tips. Additionally, COBL9 , which is involved in cell wall formation, was highly expressed in root hairs and tips in response to Cd and H 2 O 2 . Furthermore, changes in auxin and ethylene levels showed a similar pattern to that of root hair elongation and ROS at various concentrations of Cd, suggesting the involvement of auxin and ethylene in Cd/ROS-induced root hair elongation. Combined, it appears that Cd enhances root hair elongation/tip growth by elevating the expression of EXPA7 , EXPA18 and COBL9 and by inhibiting the expression of PERK5 , PERK8, and RHS10 , which are ROS-mediated in Arabidopsis. Change of root hair elongation, ROS, auxin and ethylene at various concentrations of Cd in Col-0 Arabidopsis • Cd promotes root hair elongation by enhancing ROS level in Arabidopsis. • RBOHC, RBOHH, RBOHJ, PER1, PER44, and PER73 participate in Cd-induced ROS generation. • Auxin and ethylene may be involved in Cd-enhanced ROS and root hair elongation. • Cd-induced ROS elevates expressions of EXPA7 , EXPA18 and COBL9 . • Cd-enhanced ROS inhibits expressions of PERK5 , PERK8, and RHS10 .

Intracellular reactive oxygen species trafficking participates in seed dormancy alleviation in Arabidopsis seeds.

Reactive oxygen species (ROS) release seed dormancy through an unknown mechanism. We used different seed dormancy-breaking treatments to decipher the dynamics and localization of ROS production during seed germination. We studied the involvement of ROS in the breaking of Arabidopsis seed dormancy by cold stratification, gibberellic acid (GA3 ) and light. We characterized the effects of these treatments on abscisic acid and gibberellins biosynthesis and signalling pathways. ROS, mitochondrial redox status and peroxisomes were visualized and/or quantified during seed imbibition. Finally, we performed a cytogenetic characterization of the nuclei from the embryonic axes during seed germination. We show that mitochondria participate in the early ROS production during seed imbibition and that a possible involvement of peroxisomes in later stages should still be analysed. At the time of radicle protrusion, ROS accumulated within the nucleus, which correlated with nuclear expansion and chromatin decompaction. Taken together, our results provide evidence of the role of ROS trafficking between organelles and of the nuclear redox status in the regulation of seed germination by dormancy.

N-Acetyl-L-cysteine effects on oxidative stress-induced high glucose-cultured human dermal fibroblasts

BackgroundWound healing in diabetic patients is delayed, but the mechanism of this impairment is unclear. We sought to investigate molecular changes in human dermal fibroblasts (HDFs) in a high-glucose state and improving effect of N-acetyl-L-cysteine (NAC). MethodsHDFs were cultured in 5.5, 25, 50, and 75 mM glucose concentrations for 72 h. Cell proliferation and migration were examined via in vitro scratch and 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assays. Cytotoxicity was determined through the measurement of lactate dehydrogenase (LDH). The level of intracellular reactive oxygen species (ROS) was also measured in the HDFs. Oxidative stress markers of nuclear factor erythroid 2 (NFE2)- related factor 2 (NRF2), Catalase (CAT) and Glutathione (GSH) were quantified with Real time polymerase chain reaction (PCR). The antioxidant effect of NAC, 1 mM was examined to evaluate the involvement of ROS and LDH and oxidative markers in the glucose effects on the HDFs. ResultsThe in vitro scratch assay showed that high glucose concentrations significantly reduced fibroblast migration and proliferation at 12, 24, and 48 h. The MTT assay revealed a decline in cell viability in 50 and 75 mM glucose concentrations. A significant increase in LDH and ROS levels was observed in the HDFs incubated in 50 and 75 mM glucose concentrations after 72 h. mRNA level of Nrf2, CAT and GSH were downregulated. The antioxidant addition of NAC reduced the inhibitory effect of the high-glucose state on the migration and proliferation of the HDFs. ConclusionsA high-glucose state impairs the in vitro proliferation and migration of HDFs and may, therefore, induce increased oxidative stress and cellular dysfunction. The antioxidant effect of NAC ameliorates the damaging impact of a high-glucose state.

TGF-β/Smad signaling pathway plays a crucial role in patulin-induced pro-fibrotic changes in rat kidney via modulation of slug and snail expression

Patulin (PAT) is a mycotoxin that contaminates a variety of food and foodstuffs. Earlier in vitro and in vivo findings have indicated that kidney is one of the target organs for PAT-induced toxicity. However, no study has evaluated the chronic effects of PAT exposure at environmentally relevant doses or elucidated the detailed mechanism(s) involved. Here, using in vitro and in vivo experimental approaches, we delineated the mechanism/s involved in pro-fibrotic changes in the kidney after low-dose chronic exposure to PAT. We found that non-toxic concentrations (50 nM and 100 nM) of PAT to normal rat kidney cells (NRK52E) caused a higher generation of reactive oxygen species (ROS) (mainly hydroxyl (•OH), peroxynitrite (ONOO−), and hypochlorite radical (ClO−). PAT exposure caused the activation of mitogen-activated protein kinases (MAPKs) and its downstream c-Jun/Fos signaling pathways. Moreover, our chromatin immunoprecipitation (ChIP) analysis suggested that c-Jun/Fos binds to the promoter region of Transforming growth factor beta (TGF-β1) and possibly induces its expression. Results showed that PAT-induced TGF-β1 further activates the TGF-β1/smad signaling pathways. Higher activation of slug and snail transcription factors further modulates the regulation of pro-fibrotic molecules. Similarly, in vivo results showed that PAT exposure to rats through gavage at 25 and 100 μg/kg b. wt had higher levels of kidney injury/toxicity markers namely vascular endothelial growth factor (VEGF), kidney Injury Molecule-1 (Kim-1), tissue inhibitor of metalloproteinase-1 (Timp-1), and clusterin (CLU). Additionally, histopathological analysis indicated significant alterations in renal tubules and glomeruli along with collagen deposition in PAT-treated rat kidneys. Overall, our data provide evidence of the involvement of ROS mediated MAPKs and TGF-β1/smad pathways in PAT-induced pro-fibrotic changes in the kidney via modulation of slug and snail expression.

Redox Dysregulation in Aging and COPD: Role of NOX Enzymes and Implications for Antioxidant Strategies.

With a rapidly growing elderly human population, the incidence of age-related lung diseases such as chronic obstructive pulmonary disease (COPD) continues to rise. It is widely believed that reactive oxygen species (ROS) play an important role in ageing and in age-related disease, and approaches of antioxidant supplementation have been touted as useful strategies to mitigate age-related disease progression, although success of such strategies has been very limited to date. Involvement of ROS in ageing is largely attributed to mitochondrial dysfunction and impaired adaptive antioxidant responses. NADPH oxidase (NOX) enzymes represent an important enzyme family that generates ROS in a regulated fashion for purposes of oxidative host defense and redox-based signalling, however, the associations of NOX enzymes with lung ageing or age-related lung disease have to date only been minimally addressed. The present review will focus on our current understanding of the impact of ageing on NOX biology and its consequences for age-related lung disease, particularly COPD, and will also discuss the implications of altered NOX biology for current and future antioxidant-based strategies aimed at treating these diseases.

Reactive oxygen species may influence on the crossroads of stemness, senescence, and carcinogenesis in a cell via the roles of APRO family proteins

Excessive reactive oxygen species (ROS) may cause oxidative stress which is involved in aging and in the pathogenesis of various human diseases. Whereas unregulated levels of the ROS may be harmful, regulated basal level of ROS are even necessary to support cellular functions as a second messenger for homeostasis under physiological conditions. Therefore, redox medicine could develop as a new therapeutic concept for human health-benefits. Here, we introduce the involvement of ROS on the crossroads of stemness, senescence, and carcinogenesis in a stem cell and cancer cell biology. Amazingly, the anti-proliferative (APRO) family anti-proliferative proteins characterized by immediate early growth responsive genes may also be involved in the crossroads machinery. The biological functions of APRO proteins (APROs) seem to be quite intricate, however, which might be a key modulator of microRNAs (miRNAs). Given the crucial roles of ROS and APROs for pathophysiological functions, upcoming novel therapeutics should include vigilant modulation of the redox state. Next generation of medicine including regenerative medicine and/or cancer therapy will likely comprise strategies for altering the redox environment with the APROs via the modulation of miRNAs as well as with the regulation of ROS of cells in a sustainable manner.

Autophagy is induced and modulated by cholesterol depletion through transcription of autophagy-related genes and attenuation of flux

Perturbations to cellular homeostasis, including reduction of the cholesterol level, induce autophagy, a self-digestion process of cellular constituents through an autophagosomal–lysosomal pathway. In accord with its function as a membrane organizer and metabolic sentinel, the cellular response to cholesterol depletion comprises multiple phenomena, including the activation of transcriptional responses, accumulation of reactive oxygen species (ROS), and activation of stress-related signaling pathways. However, the molecular mechanisms by which cholesterol depletion regulates autophagy and the putative involvement of transcriptional responses, ROS and/or stress-related signaling in autophagy regulation in this biological context are not fully understood. Here, we find that cholesterol depletion regulates autophagy at three different levels. First, employing RNA-seq, we show that cholesterol depletion increases the expression of autophagy-related genes independent of ROS or JNK activity. Second, analysis of LC3 lipidation and intracellular localization, and of p62 levels and degradation kinetics, reveals that cholesterol depletion mediates autophagy induction while interfering with autophagic flux. Of note, only the latter depends on ROS accumulation and JNK activity. In view of the common use of cholesterol-reducing drugs as therapeutic agents, our findings have important implications for multiple cellular settings in which autophagy plays a prominent role.

Phytochemicals from Indian Ethnomedicines: Promising Prospects for the Management of Oxidative Stress and Cancer.

Oxygen is indispensable for most organisms on the earth because of its role in respiration. However, it is also associated with several unwanted effects which may sometimes prove fatal in the long run. Such effects are more evident in cells exposed to strong oxidants containing reactive oxygen species (ROS). The adverse outcomes of oxidative metabolism are referred to as oxidative stress, which is a staple theme in contemporary medical research. Oxidative stress leads to plasma membrane disruption through lipid peroxidation and has several other deleterious effects. A large body of literature suggests the involvement of ROS in cancer, ageing, and several other health hazards of the modern world. Plant-based cures for these conditions are desperately sought after as supposedly safer alternatives to mainstream medicines. Phytochemicals, which constitute a diverse group of plant-based substances with varying roles in oxidative reactions of the body, are implicated in the treatment of cancer, aging, and all other ROS-induced anomalies. This review presents a summary of important phytochemicals extracted from medicinal plants which are a part of Indian ethnomedicine and Ayurveda and describes their possible therapeutic significance.

Reactive Oxygen Species Mediate 6c-Induced Mitochondrial and Lysosomal Dysfunction, Autophagic Cell Death, and DNA Damage in Hepatocellular Carcinoma

Increasing the level of reactive oxygen species (ROS) in cancer cells has been suggested as a viable approach to cancer therapy. Our previous study has demonstrated that mitochondria-targeted flavone-naphthalimide-polyamine conjugate 6c elevates the level of ROS in cancer cells. However, the detailed role of ROS in 6c-treated cancer cells is not clearly stated. The biological effects and in-depth mechanisms of 6c in cancer cells need to be further investigated. In this study, we confirmed that mitochondria are the main source of 6c-induced ROS, as demonstrated by an increase in 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) and MitoSox fluorescence. Compound 6c-induced mitochondrial ROS caused mitochondrial dysfunction and lysosomal destabilization confirmed by absolute quantitation (iTRAQ)-based comparative proteomics. Compound 6c-induced metabolic pathway dysfunction and lysosomal destabilization was attenuated by N-acetyl-L-cysteine (NAC). iTRAQ-based comparative proteomics showed that ROS regulated the expression of 6c-mediated proteins, and treatment with 6c promoted the formation of autophagosomes depending on ROS. Compound 6c-induced DNA damage was characterized by comet assay, p53 phosphorylation, and γH2A.X, which was diminished by pretreatment with NAC. Compound 6c-induced cell death was partially reversed by 3-methyladenine (3-MA), bafilomycin (BAF) A1, and NAC, respectively. Taken together, the data obtained in our study highlighted the involvement of mitochondrial ROS in 6c-induced autophagic cell death, mitochondrial and lysosomal dysfunction, and DNA damage.