Source Of Reactive Oxygen Species Research Articles

Nrf2 mediates mitochondrial and NADPH oxidase-derived ROS during mild heat stress at 40 °C.

Hyperthermia is an adjuvant to chemotherapy and radiotherapy and sensitizes tumors to these treatments. However, repeated heat treatments result in acquisition of heat resistance (thermotolerance) in tumors. Thermotolerance is an adaptive survival response that appears to be mediated by upregulated cellular defenses. However, the mechanisms of activation remain unclear. When HeLa cells were exposed to mild heat shock at 40 °C for 3 h, levels of superoxide and peroxides increased. Cells were treated with mitochondrial antioxidant MitoQ and NADPH oxidase (NOX) inhibitor apocynin to characterize the contribution of these two sources to the total reactive oxygen species (ROS) pool. We found that both mitochondria and NOX are sources of ROS during mild heat shock at 40 °C. Heat-derived ROS are thought to activate the adaptive survival response at 40 °C. Nrf2, the master regulator of the cellular antioxidant response, is thought to play a pivotal role in establishing the adaptive survival response. Nrf2 was overexpressed or knocked down to assess its role. Moreover, Nrf2 levels correlate with the cellular redox state, and do so via scavenging of mitochondria- and NOX-derived ROS. Knockdown of Nrf2 markedly increased levels of ROS that were scavenged by either apocynin or MitoQ. Finally, critical defense proteins such as DJ-1 and PGAM5 seemed to require a two-key activation system mediated by Nrf2 and mitochondrial ROS. Our study characterized mitochondrial and NOX-derived ROS as being essential in activating cellular defenses alongside Nrf2 and underlines potential therapeutic targets that may contribute to the acquisition of thermotolerance.

Phase partitioning of the neutrophil oxidative burst is coordinated by accessory pathways of glucose metabolism and mitochondrial activity.

Neutrophils are a part of the innate immune system and produce reactive oxygen species (ROS) to extinguish pathogens. The major source of ROS in neutrophils is NADPH oxidase, which is fueled by NADPH generated via the pentose phosphate pathway; however, it is unclear how other accessory glucose metabolism pathways and mitochondrial activity influence the respiratory burst. We examined the temporal dynamics of the respiratory burst and delineated how metabolism changes over time after neutrophil activation. Bone marrow-derived neutrophils were stimulated with phorbol 12-myristate 13-acetate, and the respiratory burst was measured via extracellular flux analysis. Metabolomics experiments utilizing 13C6-glucose highlighted the activation of glycolysis as well as ancillary pathways of glucose metabolism in activated neutrophils. Phorbol 12-myristate 13-acetate stimulation acutely increased 13C enrichment into glycerol 3-phosphate (G3P) and citrate, whereas increases in 13C enrichment in the glycogen intermediate, UDP-hexose, and end products of the hexosamine and serine biosynthetic pathways occurred only during the late phase of the oxidative burst. Targeted inhibition of the G3P shuttle, glycogenolysis, serine biosynthesis, and mitochondrial respiration demonstrated that the G3P shuttle contributes to the general magnitude of ROS production; that glycogen contributes solely to the early respiratory burst; and that the serine biosynthetic pathway activity and complex III-driven mitochondrial activity influence respiratory burst duration. Collectively, these results show that the neutrophil oxidative burst is highly dynamic, with coordinated changes in metabolism that control the initiation, magnitude, and duration of ROS production.

The Focal Induction of Reactive Oxygen Species in Rats as a Trigger of Aortic Valve Degeneration.

Degenerative aortic valve disease (DAVD) is a multifactorial process. We developed an animal model to analyze the isolated, local effect of reactive oxygen species (ROS) on its pathophysiology. We utilized a photodynamic reaction (PDR) as a source of ROS in the aortic valve by aiming a laser at the aortic valve for 60 min after the administration of a photosensitizer 24 h prior. ROS, laser, and sham groups (n = 7 each) for every observation period (t = 0; t = 8 d; t = 84 d; t = 168 d) were established. The amount of ROS generation; morphological changes; inflammatory, immune, and apoptotic reactions; and hemodynamic changes in the aortic valves were assessed using appropriate histological, immunohistological, immunohistochemical, and echocardiographic methods. The ROS group displayed an increased amount of ROS (p < 0.01) and increased inflammatory activation of the endothelium (p < 0.05) at t = 0. In the ROS group, aortic valves were calcified (p < 0.05) and the transvalvular gradient was increased (p < 0.01) at t = 168 d. The small animal model employed here may serve as a platform for analyzing ROS's isolated role in the DAVD context.

Modulation of the Atomic Spacing of Electrocatalytic for Boosting Reactive Oxygen Species Production to Precise Hepatocellular Carcinoma Cell Apoptosis.

Promoting tumor cell apoptosis through the catalytic regulation of reactive oxygen species (ROS) is an ideal therapeutic option for cancer. However, a stable and controllable exogenous source of ROS is still lacking. Efficient and controllable electrocatalysis has shown tremendous potential for cancer treatment, but its key challenge lies in achieving precise, efficient, and controllable electrocatalytic ROS production at the tumor site. This study describes an electrocatalytic treatment technique for hepatocellular carcinoma (HCC) based on traditional Chinese acupuncture. By attaching a biocompatible electrocatalyst NiO-P700 with optimal atomic spacing to the surface of silver acupuncture needles, a high-concentration ROS microenvironment was generated around tumor cells via ORRs when the needles were electrified. This induction led to the accumulation of inflammatory factors (IL-1β, IL-6, and TNF-α) and macrophage infiltration, accelerating tumor cell apoptosis and necrosis. Both in vitro and in vivo experiments demonstrated that the rate of ROS production can be rapidly controlled by adjusting voltage and current. Importantly, the high concentration of ROS can be safely and effectively confined to the lesion site without affecting the entire body. Our study attempted to integrate electrocatalysis and acupuncture in HCC treatment, successfully regulating NiO-P atomic spacing and enhancing ORR performance, thereby presenting a safe and reliable perspective for HCC therapy.

Association of NOX5 Expression with Sperm Activity and Motility in Pathospermic Infertile Men

Background: The newest NOX isoform, NOX5, has been found in mammalian spermatozoa. Many physiological and pathological situations in spermatozoa are mediated by reactive oxygen species (ROS). NOX5 is the main source of ROS in spermatozoa. Our purpose was to investigate the changes in NOX5 expression and the effect of NOX5 expression on sperm motility, chromatin integrity, and oxidative status in oligoasthenozoospermic compared to normozoospermic men. Methods: Semen samples were collected from 30 normozoospermic (NS) and 30 oligoasthenozoospermic (OAS) men. NOX5 protein expression in sperm samples was evaluated by immunohistochemistry and western blot. Oxidative stress status was evaluated by total antioxidant capacity (TAC), total oxidant capacity (TOC), and oxidative stress index (OSI) parameters. Chromatin integrity in spermatozoa was evaluated by toluidine blue staining. Results: NOX5 expression levels were significantly higher in OAS group than in NS group (p&lt;0.001). In addition, chromatin integrity was significantly higher in the OAS group in comparison to NS group (p&lt;0.001). TAC levels were higher in the NS group, but OSI and TOC levels were significantly higher in OAS group (p&lt;0.001). It was found that NOX5 protein expression was positively correlated with oxidative stress and chromatin integrity and negatively correlated with motility (p&lt;0.01). Conclusion: These results suggest that overexpression of NOX5 may be the source of excessive ROS production and oxidative stress injuries in oligoasthenozoospermic men. Considering that NOX5 expression is positively correlated with oxidative stress and chromatin integrity but negatively correlated with motility, it can be considered a biomarker to be used in assisted reproductive procedures.

Charge Separation-Engineered Piezoelectric Ultrathin Nanorods Modulate Tumor Stromal Microenvironment and Enhance Cell Immunogenicity for Synergistically Piezo-Thermal-Immune Therapy.

The tumor microenvironment (TME) is characterized by hypoxia and low immunogenicity, with a dense and rigid extracellular matrix (ECM) that impedes the diffusion of therapeutic agents and immune cells, thereby limiting the efficacy of immunotherapy. To overcome these challenges, an oxygen defect piezoelectric-photothermal sensitizer, bismuth vanadate nanorod-supported platinum nanodots (BVP) is developed. The integration of platinum enhances the photothermal effect and improves charge separation efficiency under ultrasound, leading to increased heat generation and the production of reactive oxygen species (ROS) and oxygen. Platinum also catalyzes the conversion of hydrogen peroxide in the TME to oxygen, which serves as both a ROS source and a means to alleviate tumor hypoxia, thereby reversing the immunosuppressive TME. Moreover, the coordination of bismuth ions with glutathione further amplifies cellular oxidative stress. The generated heat and ROS not only denature the collagen in the ECM, facilitating the deeper penetration of BVP into the tumor but also induce immunogenic cell death in tumor cells. Through the "degeneration and penetration" strategy, photoacoustic therapy effectively activates immune cells, inhibiting both tumor growth and metastasis. This study introduces a pioneering approach in the design of antitumor nanomedicines aimed at reversing the immunosuppressive characteristics of the TME.

Mitochondrial reactive oxygen species-mediated fibroblast activation has a role in tumor microenvironment formation in radiation carcinogenesis.

Cancer risks attributable to low-dose and low-dose-rate radiation are a serious concern for public health. Radiation risk assessment is based on lifespan studies among Hiroshima-Nagasaki A-bomb survivors; however, there are statistical limitations due to a small sample size for low-dose radiation. Therefore, basic biological studies are helpful in understanding the mechanism of radiation carcinogenesis. The detrimental effects of ionising radiation (IR) are caused by reactive oxygen species (ROS)-mediated oxidative DNA damage. IR-induced delayed ROS are produced in the electron transport chain reaction of the mitochondrial complex. Thus, mitochondria are a source of ROS and a primary target for ROS attacks. Consequently, mitochondrial dysfunction is thought to be a key event in the metabolic changes of cancer cells and is important in radiation-induced carcinogenesis. In this paper, we present recent findings on radiation carcinogenesis effect assessment, focusing on mitochondrial function as stress sensors.

Inhibition of VDAC1 oligomerization blocks cysteine deprivation-induced ferroptosis via mitochondrial ROS suppression

Ferroptosis, a regulated form of cell death dependent on reactive oxygen species (ROS), is characterized by iron accumulation and lethal lipid peroxidation. Mitochondria serve as the primary source of ROS and thus play a crucial role in ferroptosis initiation and execution. This study highlights the role of mitochondrial ROS and the significance of voltage-dependent anion channel 1 (VDAC1) oligomerization in ferroptosis induced by cysteine deprivation or ferroptosis-inducer RSL3. Our results demonstrate that the mitochondria-targeted antioxidants MitoQ and MitoT effectively block ferroptosis induction and that dysfunction of complex III of the mitochondrial electron transport chain contributes to ferroptosis induction. Pharmacological inhibitors that target VDAC1 oligomerization have emerged as potent suppressors of ferroptosis that reduce mitochondrial ROS production. These findings underscore the critical involvement of mitochondrial ROS production via complex III of the electron transport chain and the essential role of VDAC1 oligomerization in ferroptosis induced by cysteine deprivation or RSL3. This study deepens our understanding of the intricate molecular networks governing ferroptosis and provides insights into the development of novel therapeutic strategies targeting dysregulated cell death pathways.

Boosting Tumor Apoptosis and Ferroptosis with Multienzyme Mimetic Au Single‐Atom Nanozymes Engaged in Cascade Catalysis

AbstractNanozyme‐based catalytic therapy has garnered much attention in cancer treatment for converting endogenous substrates into reactive oxygen species (ROS), which induce oxidative stress damage in tumors. However, the effectiveness of nanozymes is hindered by the limited availability of these endogenous substrates in the tumor microenvironment. To address this, a novel gold‐based single‐atom nanozyme (AuSAN), glucose oxidase (GOx, G), and lactate oxidase (LOx, L) are meticulously engineered into a highly ordered biomimetic composite nanozyme M/GLB@AuSAN, forming an interconnected cascade catalysis that catalyzes the carbon sources of tumor into ROS as a sustained antitumor strategy. The loaded GOx and LOx aerobically catalyze glucose and lactate to produce H2O2, which is then rapidly converted into ·OH, O2•−, and O2 by AuSAN. The generated O2 serves as a positive feedback substrate for further GOx‐ and LOx‐mediated aerobic catalysis, significantly amplifying cascade catalysis, and thereby enhancing ROS accumulation. The abundant intracellular ROS and scarce carbon sources effectively exacerbate protein phosphorylation, lipid peroxidation, and mitochondrial damage, ultimately provoking tumor apoptosis and ferroptosis in vitro and in vivo. Therefore, the integrated design of GOx/LOx/AuSAN provides a promising strategy to combine multiple enzymatic activities, deplete carbon sources, and enhance ROS production, resulting in the suppression of melanoma progression.

Blocking M2-Like Macrophage Polarization Using Decoy Oligodeoxynucleotide-Based Gene Therapy Prevents Immune Evasion for Pancreatic Cancer Treatment.

M2-like macrophages exhibit immunosuppressive activity and promote pancreatic cancer progression. Reactive oxygen species (ROS) affect macrophage polarization; however, the mechanism remains unclear. This study aimed to elucidate the underlying molecular basis and design a gene therapy to inhibit M2-like polarization. Microarray analysis and immunofluorescence staining were performed in M1-like and M2-like macrophages to ascertain the expression of CYBB, a major intracellular ROS source. Coculture assay and syngeneic orthotopic pancreatic cancer mice models were used to study the mechanism of M2-like skewing. Decoy oligodeoxynucleotides (ODNs) were designed to manipulate CYBB transcription to inhibit M2-like polarization and control tumor growth. Lipopolysaccharide treatment polarized U937 cells to M1-like macrophages in which CYBB expression was increased. In contrast, coculture with PANC-1 cells induced M2-like polarization in U937 cells with CYBB downregulation. High CD204 M2-like expression in combination with low CYBB expression was associated with the worst prognosis in patients with pancreatic cancer. STAT6 and HDAC2 in U937 cells were activated by cancer cell-derived IL4 after coculture and then bound to the CYBB promoter to repress CYBB expression, resulting in M2-like polarization. Diphenyleneiodonium, 8λ³-iodatricyclo[7.4.0.02,⁷]trideca-1(13),2,4,6,9,11-hexaen-8-ylium chloride that inhibits ROS production could block this action. Knockdown of STAT6 and HDAC2 also inhibited M2-like polarization and maintained the M1-like phenotype of U937 cells after coculture. Decoy ODNs interrupting the binding of STAT6 to the CYBB promoter counteracted M2-like polarization and tumor growth and triggered antitumor immunity in vivo. Gene therapy using STAT6-CYBB decoy ODNs can inhibit M2-like polarization, representing a potential therapeutic tool for pancreatic cancer.

Inhibition of calpain reduces oxidative stress and attenuates pyroptosis and ferroptosis in Clostridium perfringens Beta-1 toxin-induced macrophages

Clostridium perfringens Beta-1 toxin (CPB1) is a lethal toxin, which can lead to necrotic enteritis, but the pathological mechanism has not been elucidated. We investigated whether reactive oxygen species (ROS) participated in CPB1-induced pyroptosis and ferroptosis, and investigated the effects of calpain on CPB1-induced oxidative stress and inflammation. Scavenging ROS by N-acetyl cysteine (NAC) led to the reduction of ROS, inhibited the death of macrophages, cytoplasmic swelling and membrane rupture, the expression of pyroptosis-related proteins and proinflammatory factor, while increased the expression of anti-inflammatory factors in cells treated with rCPB1. Adenosine triphosphate (ATP) synthase, H+ transporting, mitochondrial F1 complex, alpha subunit 1 (ATP5A1) was identified specifically interact with rCPB1. Silencing ATP5A1 inhibited accumulation of ATP and ROS, leaded to less cytoplasmic swelling and membrane rupture, attenuated pyroptosis and inflammation in rCPB1-treated cells. We also found that rCPB1 induces ferroptosis in macrophages, and the level of ferroptosis was similar with H2O2. Of note, H2O2 is a major ROS source, indicated that ROS production may play a major role in the regulation of ferroptosis in macrophages treated with rCPB1. This finding was further corroborated in rCPB1- induced human acute monocytic leukemia cells, which were treated with NAC. In addition, the inhibition of ferroptosis using liproxstatin-1 inhibited the shriveled mitochondrial morphology, increased the expression of glutathione peroxidase 4, nicotinamide adenine dinucleotide (phosphate) hydrogen: quinone oxidoreductase 1 and cysteine/glutamic acid reverse transport solute carrier family 7 members 11, decreased the expression of heme oxygenase 1, nuclear receptor coactivator 4 and transferrin receptor proteins, reduced malondialdehyde and lipid peroxidation levels, and increased intracellular L-glutathione levels in cells treated with rCPB1. Furthermore, calpain inhibitor PD151746 was used to investigate how pyroptosis and ferroptosis were involved simultaneously in rCPB1-treated macrophages. We showed that PD151746 inhibited ATP and ROS production, reversed the representative pyroptosis/ferroptosis indicators and subsequently reduced inflammation. The above findings indicate that rCPB1 might lead to macrophage pyroptosis and ferroptosis through the large and sustained increase in intracellular calpain and oxidative stress, further lead to inflammation.

Energy Metabolism Enhance Perylenequinone Biosynthesis in Shiraia sp. Slf14 through Promoting Mitochondrial ROS Accumulation.

Perylenequinones (PQs) are important natural compounds that have been extensively utilized in recent years as agents for antimicrobial, anticancer, and antiviral photodynamic therapies. In this study, we investigated the molecular mechanisms regulating PQ biosynthesis by comparing Shiraia sp. Slf14 with its low PQ titer mutant, Slf14(w). The results indicated that the strain Slf14 exhibited a higher PQ yield, a more vigorous energy metabolism, and a more pronounced oxidation state compared to Slf14(w). Transcriptome analysis consistently revealed that the differences in gene expression between Slf14 and Slf14(w) are primarily associated with genes involved in redox processes and energy metabolism. Additionally, reactive oxygen species (ROS) were shown to play a crucial role in promoting PQ synthesis, as evidenced by the application of ROS-related inhibitors and promoters. Further results demonstrated that mitochondria are significant sources of ROS, which effectively regulate PQ biosynthesis in Shiraia sp. Slf14. In summary, this research revealed a noteworthy finding: the higher energy metabolism of the strain Slf14 is associated with increased intracellular ROS accumulation, which in turn triggers the activation and expression of gene clusters responsible for PQ synthesis.

Ginseng rusty root symptoms result from nitric oxide stress in soil

Ginseng, from the roots of Panax ginseng C. A. Meyer, is a widely used herbal medicine in Asian countries, known for its excellent therapeutic properties. The growth of P. ginseng is depend on specific and strict environments, with a preference for wetness but intolerance for flooding. Under excessive soil moisture, some irregular rust-like substances are deposited on the root epidermis, causing ginseng rusty symptoms (GRS). This condition leads to a significant reduce in yield and quality, resulting in substantial economic loses. However, there is less knowledge on the cause of GRS and there are no effective treatments available for its treatment once it occurs. Unsuitable environments lead to the generation of large amounts of reactive oxygen species (ROS). We investigated the key indicators associated with the stress response during different physiological stages of GRS development. We observed a significant change in ROS level, MDA contents, antioxidant enzymes activities, and non-enzymatic antioxidants contents prior to the GRS. Through the analysis of soil features with an abundance of moisture, we further determined the source of ROS. The levels of nitrate reductase (NR) and nitric oxide synthase (NOS) activities in the inter-root soil of ginseng with GRS were significantly elevated compared to those of healthy ginseng. These enzymes boost nitric oxide (NO) levels, which in turn showed a favorable correlation with the GRS. The activities of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase first rose and then decreased as GRS developed. Excess soil moisture causes a decrease in oxygen levels. This activated NR and NOS in the soil, resulting in a production of excess NO. The NO then diffused into the ginseng root and triggered a burst of ROS through NADPH located on the cell membrane. Additionally, Fe2+ in soil was oxidized to red Fe3+, and finally led to GRS. This conclusion was also verified by the Sodium Nitroprusside (SNP), a precursor compound producing NO. The presence of NO from NR and NOS in water-saturated soil is responsible for the generation of ROS. Among these, NO is the main component that contribute to the occurrence of GRS.

Evaluating the Diverse Anticancer Effects of Laos Kaempferia parviflora (Black Ginger) on Human Melanoma Cell Lines.

Cancer has become a consistent concern globally and increasingly fatal. Malignant melanoma is a rising concern, with its increased mortality. Kaempferia parviflora Wall. ex Baker (K. parviflora (KP)), commonly known as black ginger, is well known for its medicinal contributions. For the first time, in the following study we investigated the antimelanoma potential of Laos KP extracts in human cell lines. KP extracts (KPE) in methanol, DCM, and ethyl acetate showed strong cell inhibition in both melanomas, with KPE-DCM being particularly effective in inhibiting melanoma cell migration, invasion, and proliferation by inducing cell cycle arrest and apoptosis, while KPE-Hexane exhibited a low cell inhibition rate and a more limited effect. KPE affected the increased expression of caspase-3, PARP andBax and the decreased expression of the BcL-2, Mu-2-related death-inducing gene (MUDENG, MuD) protein. Furthermore, KPE enhanced apoptotic cells in the absence and presence of the pancaspase inhibitor Z-VAD-FMK. Interestingly, these apoptotic cells were significantly suppressed by the caspase inhibitor. Moreover, elevated mitochondrial membrane potential (MMP) and intracellular reactive oxygen species (ROS) levels, suggestive of KPE's mitochondrial-mediated apoptosis in melanoma cells, were also confirmed. KPE treatment increased MMP levels, and upregulated the generation of ROS in A375 cells but not in A2058 cells. However, pretreatment with an ROS scavenger (NAC) suppressed KPE-induced cell death and ROS generation. These results clearly pointed out KPE-induced mitochondrial-mediated apoptotic cell death as the mechanism behind the inhibition of the human melanoma cells. Future studies exploring the role of specific ROS sources and their interaction with mitochondrial dynamics could deepen the existing understanding on KPE-induced apoptosis.

Oxidative Stress and Erectile Dysfunction: Pathophysiology, Impacts, and Potential Treatments.

Erectile dysfunction (ED) is a prevalent condition affecting men's sexual health, with oxidative stress (OS) having recently been identified as a significant contributing causative factor. This narrative review aims to elucidate the role of OS in the pathophysiology of ED, focusing on impact, mechanisms, and potential therapeutic interventions. Key findings indicate that OS disrupts endothelial function and nitric oxide (NO) signaling, crucial for erectile function. Various sources of reactive oxygen species (ROS) and their detrimental effects on penile tissue are discussed, including aging, diabetes mellitus, hypertension, hyperlipidemia, smoking, obesity, alcohol consumption, psychological stress, hyperhomocysteinemia, chronic kidney disease, and sickle cell disease. Major sources of ROS, such as NADPH oxidase, xanthine oxidase, uncoupled endothelial NO synthase (eNOS), and mitochondrial electron transport, are identified. NO is scavenged by these ROS, leading to endothelial dysfunction characterized by reduced NO availability, impaired vasodilation, increased vascular tone, and inflammation. This ultimately results in ED due to decreased blood flow to penile tissue and the inability to achieve or maintain an erection. Furthermore, ROS impact the transmission of nitrergic neurotransmitters by causing the death of nitrergic neurons and reducing the signaling of neuronal NO synthase (nNOS), exacerbating ED. Therapeutic approaches targeting OS, including antioxidants and lifestyle modifications, show promise in ameliorating ED symptoms. The review underscores the need for further research to develop effective treatments, emphasizing the interplay between OS and vascular health in ED. Integrating pharmacological and non-pharmacological strategies could enhance clinical outcomes for ED patients, advocating for OS management in ED treatment protocols to improve patient quality of life.

MVP enhances FGF21-induced ferroptosis in hepatocellular carcinoma by increasing lipid peroxidation through regulation of NOX4.

Ferroptosis is a novel, iron-dependent regulatory cell death mainly caused by an imbalance between the production and degradation of intracellular reactive oxygen species (ROS). Recently, ferroptosis induction has been considered a potential therapeutic approach for hepatocellular carcinoma (HCC). Fibroblast growth factor 21 (FGF21) is a new modulator of ferroptosis; however, the regulatory role of FGF21 in HCC ferroptosis has not been investigated. In this study, we explored the role of FGF21 and its underlying molecular mechanism in the ferroptotic death of HCC cells. We identified Major vault protein (MVP) as a target of FGF21 and revealed that knockdown of MVP inhibited the lipid peroxidation levels of HCC cells by decreasing NADPH oxidase 4 (NOX4, a major source of ROS) transcription, thereby attenuating the effect of FGF21-mediated ferroptosis. On the other hand, MVP overexpression showed the opposite results. Mechanistically, MVP binds to IRF1 and thus interferes with the interaction between IRF1 and the YAP1 promoter, leading to an increase in NOX4 transcription. Importantly, forced expression of IRF1 or downregulation of YAP1 partially reversed the effect of MVP overexpression on HCC ferroptosis. Furthermore, the results in xenograft tumor models suggested that overexpression of MVP can efficiently increase the level of lipid peroxidation invivo. Taken together, these results provide new insights into the regulatory mechanism of ferroptosis in HCC.

Furanodienone induces apoptosis via regulating the PRDX1/MAPKs/p53/caspases signaling axis through NOX4-derived mitochondrial ROS in colorectal cancer cells

Furanodienone, a biologically active constituent of sesquiterpenes isolated from Rhizome Curcumae, has been reported to induce apoptosis in human colorectal cancer (CRC) cells by promoting the generation of reactive oxygen species (ROS). However, the source of ROS and how it manipulates apoptosis in CRC cells remains to be elucidated. Herein, we assessed the potential role of the well-known sources of intracellular ROS—mitochondrial electron transport chain and the nicotinamide adenine dinucleotide phosphate oxidases (NOXs), on furanodienone-induced cell death. The results indicated that furanodienone substantially increased the levels of mitochondrial ROS, which were subsequently eliminated by the general NOX inhibitor. Specifically, the nuclear factor kappa-B (NF-κB) translocation triggered a significant rise in the expression of NOX4, an isoform of the NOXs family, upon furanodienone treatment. Nevertheless, the specific NOX4 inhibitor GLX351322 attenuated cell apoptosis and mitochondrial ROS production. As a result, ROS burst induced by furanodienone suppressed the expression of peroxiredoxin1 (PRDX1), a redox signaling protein overexpressed in CRC cells, through a nuclear factor-erythroid-2-related factor 2 (Nrf2)-dependent pathway, thus amplifying the mitogen-activated protein kinases (MAPKs)/p53-mediated apoptotic signaling by increasing the p-p38, p-JNK levels, as well as the cleaved caspases −3, −8 and −9. In vivo experiments further confirmed the anti-proliferative impact of PRDX1 following furanodienone treatment. In summary, the study demonstrated that furanodienone-induced apoptosis in CRC cells is initiated by mitochondrial ROS derived from NOX4, which targeted the PRDX1 and activated the downstream MAPKs/p53-mediated caspase-dependent signaling pathway. Our findings may provide novel insights into the development of adjuvant drugs for CRC treatment and therapeutic applications.

Reactive oxygen species in hypertension.

Hypertension is a leading risk factor for stroke, heart disease and chronic kidney disease. Multiple interacting factors and organ systems increase blood pressure and cause target-organ damage. Among the many molecular elements involved in the development of hypertension are reactive oxygen species (ROS), which influence cellular processes in systems that contribute to blood pressure elevation (such as the cardiovascular, renal, immune and central nervous systems, or the renin-angiotensin-aldosterone system). Dysregulated ROS production (oxidative stress) is a hallmark of hypertension in humans and experimental models. Of the many ROS-generating enzymes, NADPH oxidases are the most important in the development of hypertension. At the cellular level, ROS influence signalling pathways that define cell fate and function. Oxidative stress promotes aberrant redox signalling and cell injury, causing endothelial dysfunction, vascular damage, cardiovascular remodelling, inflammation and renal injury, which are all important in both the causes and consequences of hypertension. ROS scavengers reduce blood pressure in almost all experimental models of hypertension; however, clinical trials of antioxidants have yielded mixed results. In this Review, we highlight the latest advances in the understanding of the role and the clinical implications of ROS in hypertension. We focus on cellular sources of ROS, molecular mechanisms of oxidative stress and alterations in redox signalling in organ systems, and their contributions to hypertension.

NADPH oxidase 5: Where are we now and which way to proceed?

Since the incorporation of mitochondria in early eukaryotes cells struggle to keep the deleterious effects of reactive oxygen species (ROS), mainly originating from the respiratory chain, at bay. Evolutionary adaptation to ROS burden went so far that by acting as messenger and effector molecules, ROS became important in maintaining homeostasis. The evolutionary success of this phenomenon is underscored by the arising of professional ROS-generating enzymes, namely the family of NADPH oxidases (NOXes). NOXes, by shaping ROS levels at different subcellular locations and in extracellular space, are involved in such fundamental functions as proliferation, differentiation, apoptosis, host defense, fertilization, and hormone biosynthesis. NOX5, being a calcium-regulated professional ROS source exerts its function at the crossroad of these two fundamental but potentially deleterious intracellular signaling pathways (i.e. Ca2+ and ROS). The expression of NOX5 in the adult human body under unchallenged conditions is restricted to very few sites, among which the two major tissue groups are genital organs (mainly testis) and immune tissues (mainly spleen). In cases of increased cellular proliferation and protein synthesis (e.g., diverse tumors, cultured primary cells, or sites of tissue damage) the expression and activity of NOX5 is often upregulated in various tissues. This and the evolutionary conserved nature of NOX5 would imply a very fundamental role for this enzyme, but intriguingly the genomes of rodents essentially lack the NOX5 gene. The latter fact had been a major obstacle in determining the physiological roles of NOX5 in normal tissues until the very recent generation of a NOX5-deficient rabbit model.

The Role of Twist1 in Chronic Pancreatitis–Associated Pancreatic Stellate Cells

In a healthy pancreas, pancreatic stellate cells (PaSCs) synthesize the basement membrane, which is mainly composed of collagen IV and laminin. In chronic pancreatitis (CP), PaSCs are responsible for the production of a rigid extracellular matrix (ECM), which is mainly composed of fibronectin and collagen I/III. Reactive oxygen species (ROS) evoke the formation of the rigid ECM by PaSCs. One of the sources of ROS is NADPH oxidase (Nox) enzymes. Nox1 up-regulates the expression of Twist1 and matrix metalloproteinase (MMP) 9 in PaSCs from mice with CP. Here 1) the functional relationship between Twist1 and MMP-9, and other PaSC-produced proteins, and 2) the extent to which Twist1 regulates the digestion of ECM proteins in CP were determined. Twist1 induced the expression of MMP-9 in mPaSCs. The action of Twist1 was not selective to MMP-9 because Twist1 induced the expression of collagen I, collagen IV, fibronectin, TGF-β, and αSMA. Using luciferase assay, Twist1 in hPaSCs increased the expression of MMP-9 at the transcriptional level in a NF-ĸB dependent manner. The digestion of collagen I/III by MMP-9 secreted by PaSCs from mice with CP was dependent on Twist1. Thus, Twist1 in PaSCs from mice with CP induces the production of a rigid ECM and the transcription of MMP-9 in a NF-ĸB dependent mechanism that selectively displays a proteolytic activity toward collagen I/III.