Induction Of Reactive Oxygen Species Research Articles

Cyclosporin A toxicity on endothelial cells differentiated from induced pluripotent stem cells: Assembling an adverse outcome pathway.

Cyclosporin A (CSA) is a potent immunosuppressive agent in pharmacologic studies. However, there is evidence for side effects, specifically in regard to vascular dysfunction. Its mode of action inducing endothelial cell toxicity is partially unclear, and a connection with an adverse outcome pathway (AOP) is not established yet. Therefore, we designed this study to get deeper insights into the mechanistic toxicology of CSA on angiogenesis. Stem cells, especially induced pluripotent stem cells (iPSCs) with the ability of differentiation to all organs of the body, are considered a promising in vitro model to reduce animal experimentation. In this study, we differentiated iPSCs to endothelial cells (ECs) as one cell type that in other studies would allow to generate cells or organoids from single donors. Flow cytometry and immunostaining confirmed our scalable differentiation protocol. Then dose and time course experiments assessing CSA cytotoxicity on iPS derived endothelial cells were performed. Transcriptomic data suggested CDA dependent induction of reactive oxygen species (ROS) and mitochondrial dysfunction, which was confirmed by in vitro experiments. Additionally, CSA impaired angiogenesis via ROS induction. Finally, we combined this information into an AOP, was developed based on here observed and literature based evidence for CSA-mediated endothelial cell toxicity. This AOP will help to design in vitro test batteries, model events observed in human toxicity studies, as well for predictive toxicology.

Aspirin enhances radio/chemo-therapy sensitivity in C. elegans by inducing germ cell apoptosis and suppresses RAS overactivated tumorigenesis via mtROS-mediated DNA damage and MAPK pathway

Previous studies have demonstrated that combination therapy involving radiotherapy and aspirin decreases the survival rate of cancer cells. However, the mechanism by which aspirin exerts its radiation sensitization effect at the in vivo level remains largely unclear. In this study, we employed Caenorhabditis elegans (C. elegans) as a model organism to investigate the effect of aspirin combined with radio/chemo-therapy on tumors at the individual level. Here, we illustrate that high-dose aspirin increases the expression of genes involved in core apoptosis pathways (egl-1, ced-9, ced-4 and ced-3) and induces germ cell apoptosis in C. elegans through mitochondrial outer membrane permeabilization (MOMP) and elevation of reactive oxygen species (ROS) levels. Crucially, aspirin-induces ROS upregulates the expression of genes critical for DNA damage response (hus-1, clk-2 and cep-1) and genes involved in MAPK pathways (lin-45, mek-2, mpk-1, sek-1 and pmk-1), thereby mediating the enhanced sensitivity of radio/chemo-therapy by aspirin. Notably, aspirin fails to induce germ cell apoptosis and enhance radio/chemo-therapy in C. elegans lacking the expression of each of those genes. Furthermore, in a C. elegans tumor-like symptom model, aspirin enhances radio/chemo-therapy sensitivity through ROS induction. However, low-dose aspirin can diminish the apoptotic signal of reproductive cells in C. elegans and exert anti-inflammatory effects. Our research results suggest that the tumor-suppressive and radio/chemo-therapy sensitizing effects of aspirin provide robust experimental evidence for improving the clinical efficacy of tumor radio/chemo-therapy and deepening our understanding of aspirin's mechanism of action in cancer.

Advanced glycation end products promote ROS production via PKC/p47 phox axis in skeletal muscle cells.

Advanced glycation end products (AGEs) are risk factors for various diseases, including sarcopenia. One of the deleterious effects of AGEs is the induction of abnormal reactive oxygen species (ROS) production in skeletal muscle. However, the underlying mechanism remains poorly understood. Therefore, the aim of this study was to elucidate how AGEs induce ROS production in skeletal muscle cells. This study demonstrated that AGEs treatment promoted ROS production in myoblasts and myotubes while PKC inhibitor abolished ROS production by AGEs stimulation. Phosphorylation of p47 phox by kinases such as PKCα is required to form the Nox2 complex, which induces ROS production. In this study, AGEs treatment promoted the phosphorylation of PKCα and p47 phox in myoblasts and myotubes. Our findings suggest that AGEs promote ROS production through the phosphorylation of PKCα and p47 phox in skeletal muscle cells.

MiR-146a Is Mutually Regulated by High Glucose-Induced Oxidative Stress in Human Periodontal Ligament Cells.

The high-glucose conditions caused by diabetes mellitus (DM) exert several effects on cells, including inflammation. miR-146a, a kind of miRNA, is involved in inflammation and may be regulated mutually with reactive oxygen species (ROS), which are produced under high-glucose conditions. In the present study, we used human periodontal ligament cells (hPDLCs) to determine the effects of the high-glucose conditions of miR-146a and their involvement in the regulation of oxidative stress and inflammatory cytokines using Western blotting, PCR, ELISA and other methods. When hPDLCs were subjected to high glucose (24 mM), cell proliferation was not affected; inflammatory cytokine expression, ROS induction, interleukin-1 receptor-associated kinase 1 (IRAK1) and TNF receptor-associated factor 6 (TRAF6) expression increased, but miR-146a expression decreased. Inhibition of ROS induction with the antioxidant N-acetyl-L-cysteine restored miR-146a expression and decreased inflammatory cytokine expression compared to those under high-glucose conditions. In addition, overexpression of miR-146a significantly suppressed the expression of the inflammatory cytokines IRAK1 and TRAF6, regardless of the glucose condition. Our findings suggest that oxidative stress and miR-146a expression are mutually regulated in hPDLCs under high-glucose conditions.

NRF2 protects lung epithelial cells from wood smoke particle toxicity

Wildfire smoke is a potential source of oxidative stress in lung epithelial tissue. The response to oxidative stress is controlled by the transcription factor NRF2, which is the central regulator of antioxidant gene expression. If wood smoke particle (WSP) exposure induces reactive oxygen species (ROS) in epithelial cells, then NRF2 may protect against pathological conditions resulting from increased oxidative stress through changes in gene expression. We used two lung epithelial cell lines to test this hypothesis in vitro: A549, which harbor a mutation resulting in constitutive activation of NRF2, and BEAS-2B, which show limited NRF2 activity under basal conditions, but high inducibility during oxidative stress. In BEAS-2B cells, WSP exposure leads to increased cellular ROS, activation of NRF2, and upregulation of the NRF2 target genes NQO1, GCLM, and SRXN1. WSP exposure also increased ROS in A549 cells, although NRF2 activation and antioxidant gene upregulation were less robust as both were basally high in this cell line. Overall, the degree of ROS induction by WSP across cell lines is dependent upon NRF2 activity, and a similar pattern was observed for WSP cytotoxicity. WSP also sensitized both cell lines to the ferroptosis inducer erastin in a manner that is correlated with NRF2 activity. Knockout of NRF2 in A549 resulted in higher WSP-induced ROS generation, cytotoxicity, and erastin sensitivity. Taken together, these results suggest that NRF2 serves as a protective factor against wood smoke induced ROS and oxidative stress in lung epithelial cells.

RIPK4 promotes oxidative stress and ferroptotic death through the downregulation of ACSM1

One of the most critical axes for cell fate determination is how cells respond to excessive reactive oxygen species (ROS)-oxidative stress. Extensive lipid peroxidation commits cells to death via a distinct cell death paradigm termed ferroptosis. However, the molecular mechanism regulating cellular fates to distinct ROS remains incompletely understood. Through siRNA against human receptor-interacting protein kinase (RIPK) family members, we found that RIPK4 is crucial for oxidative stress and ferroptotic death. Upon ROS induction, RIPK4 is rapidly activated, and the kinase activity of RIPK4 is indispensable to induce cell death. Specific ablation of RIPK4 in kidney proximal tubules protects mice from acute kidney injury induced by cisplatin and renal ischemia/reperfusion. RNA sequencing revealed the dramatically decreased expression of acyl-CoA synthetase medium-chain (ACSM) family members induced by cisplatin treatment which is compromised in RIPK4-deficient mice. Among these ACSM family members, suppression of ACSM1 strongly augments oxidative stress and ferroptotic cell death with induced expression of ACS long-chain family member 4, an important component for ferroptosis execution. Our lipidome analysis revealed that overexpression of ACSM1 leads to the accumulation of monounsaturated fatty acids, attenuation of polyunsaturated fatty acid (PUFAs) production, and thereby cellular resistance to ferroptosis. Hence, knockdown of ACSM1 resensitizes RIPK4 KO cells to oxidative stress and ferroptotic death. In conclusion, RIPK4 is a key player involved in oxidative stress and ferroptotic death, which is potentially important for a broad spectrum of human pathologies. The link between the RIPK4-ASCM1 axis to PUFAs and ferroptosis reveals a unique mechanism to oxidative stress-induced necrosis and ferroptosis.

MiR-29b inhibits COC expansion and oocyte in vitro maturation via induction of ROS by targeting CYCS

Cumulus-oocyte complex (COC) expansion and oocyte maturation are crucial processes for embryo development and fertility across species. Although miR-29b has been detected in porcine ovarian granulosa cells, its specific role in regulating oocyte maturation remains largely unknown. In this study, using the pig as a model, we report that over-expression of miR-29b lead to a decrease of COC expansion area and inhibits oocyte maturation (P<0.05). This suppression correlated with a decrease expression of COC-expansion-associated genes, including SHAS2, ADAMTS1, ADAMTS2, ADAMTS17 and PTX 3 in both mural granulosa cells (mGCs) and cumulus granulosa cells (cGCs). Further investigation revealed that miR-29b over-expression induces reactive oxygen species (ROS) accumulation in both mGCs and cGCs, conversely, knock-down of miR-29b reverses all these effects. Treatment with the antioxidant β-mercaptoethanol alleviates ROS accumulation, rescues COC expansion and restores oocyte polar body formation impaired by miR-29b mimics. Computational analysis predicted CYCS, the gene encoding cytochrome C, as a potential target of miR-29b. Subsequent examination demonstrated that miR-29b downregulates CYCS at both mRNA and protein levels. Dual-luciferase reporter assays further confirmed that miR-29b interacts with the 3’-untranslated region (3’UTR) of CYCS. Over-expression of CYCS decreases ROS accumulation and promotes COC expansion (P<0.05). These results indicate that miR-29b regulates COC expansion and oocyte maturation in vitro by inducing ROS, likely through targeting of CYCS. This study sheds light on the role of miR-29b in oocyte maturation and provides insight into the regulatory function of miRNAs in ovarian physiology.

Iron chelation as a new therapeutic approach to prevent senescence and liver fibrosis progression

Iron overload and cellular senescence have been implicated in liver fibrosis, but their possible mechanistic connection has not been explored. To address this, we have delved into the role of iron and senescence in an experimental model of chronic liver injury, analyzing whether an iron chelator would prevent liver fibrosis by decreasing hepatocyte senescence. The model of carbon tetrachloride (CCl4) in mice was used as an experimental model of liver fibrosis. Results demonstrated that during the progression of liver fibrosis, accumulation of iron occurs, concomitant with the appearance of fibrotic areas and cells undergoing senescence. Isolated parenchymal hepatocytes from CCl4-treated mice present a gene transcriptomic signature compatible with iron accumulation and senescence, which correlates with induction of Reactive Oxygen Species (ROS)-related genes, activation of the Transforming Growth Factor-beta (TGF-β) pathway and inhibition of oxidative metabolism. Analysis of the iron-related gene signature in a published single-cell RNA-seq dataset from CCl4-treated livers showed iron accumulation correlating with senescence in other non-parenchymal liver cells. Treatment with deferiprone, an iron chelator, attenuated iron accumulation, fibrosis and senescence, concomitant with relevant changes in the senescent-associated secretome (SASP), which switched toward a more anti-inflammatory profile of cytokines. In vitro experiments in human hepatocyte HH4 cells demonstrated that iron accumulates in response to a senescence-inducing reagent, doxorubicin, being deferiprone able to prevent senescence and SASP, attenuating growth arrest and cell death. However, deferiprone did not significantly affect senescence induced by two different agents (doxorubicin and deoxycholic acid) or activation markers in human hepatic stellate LX-2 cells. Transcriptomic data from patients with different etiologies demonstrated the relevance of iron accumulation in the progression of liver chronic damage and fibrosis, correlating with a SASP-related gene signature and pivotal hallmarks of fibrotic changes. Altogether, our study establishes iron accumulation as a clinically exploitable driver to attenuate pathological senescence in hepatocytes.

Bushen Huoxue formula attenuates lipid accumulation evoking excessive autophagy in premature ovarian insufficiency rats and palmitic acid-challenged KGN cells by modulating lipid metabolism.

Premature ovarian insufficiency (POI) has affected about 3.7% of women of reproductive age and is a major factor contributing to infertility. Bushen Huoxue formula (BHF), a traditional Chinese medicine prescription, is clinically used to treat POI in China. This study aims to investigate the potential mechanisms of BHF in combating POI using corticosterone-induced rats and palmitic acid (PA)-challenged human ovarian granulosa cells (GCs). Initially, ultra performance liquid chromatography tandem mass spectrometry was employed to analyze the components of BHF. The pharmacodynamic parameters evaluated included body weight, ovaries index, and serum hormone in rats. Follicle numbers were observed using H&E staining. Additionally, PCNA and TUNEL staining were used to assess GCs proliferation and apoptosis, respectively. Lipid accumulation and ROS levels were examined using Oil Red O and ROS staining. Protein expressions were determined by western blot. To probe mechanisms, cell viability and E2 levels in BHF-treated, PA-stimulated GCs were determined using MTT and ELISA, respectively. Cell apoptosis and ROS levels were assessed using TUNEL and ROS staining. Proteins related to lipid metabolism and autophagy in PA-stimulated GCs were studied using agonists. Our results shown that BHF effectively normalized serum hormone levels, including follicle-stimulating hormone (FSH), anti-Müllerian hormone (AMH), estradiol (E2), and luteinizing hormone (LH). Concurrently, BHF also significantly reduced follicular atresia and promoted cell proliferation while inhibiting apoptosis in POI rats. Furthermore, BHF mitigated ovarian lipid accumulation by modulating lipid metabolism, which included reducing lipid synthesis (expression of peroxisome proliferator-activated receptor γ and CCAAT/enhancer binding protein α), increasing lipid catabolism (expression of adipose triglyceride lipase), and enhancing lipid oxidation (expression of carnitine palmitoyl transferase 1A). Mechanistically, the therapeutic effects of BHF on POI were linked with alleviation of lipid deposition-induced reactive oxygen species (ROS) accumulation and excessive autophagy, corroborating the results in PA-challenged GCs. After treatment with elesclomol (a ROS inducer) and rapamycin (an autophagy inducer) in GCs, the effects of BHF were almost counteracted under model conditions. These findings suggest that BHF alleviates the symptoms of POI by altering lipid metabolism and reducing lipid accumulation-induced ROS and autophagy, offering evidence for BHF's efficacy in treating POI clinically.

Novel platinum therapeutics induce rapid cancer cell death through triggering intracellular ROS storm

Induction of reactive oxygen species (ROS) production in cancer cells plays a critical role for cancer treatment. However, therapeutic efficiency remains challenging due to insufficient ROS production of current ROS inducers. We designed a novel platinum (Pt)-based drug named “carrier-platin” that integrates ultrasmall Pt-based nanoparticles uniformly confined within a poly(amino acids) carrier. Carrier-platin dramatically triggered a burst of ROS in cancer cells, leading to cancer cell death as quick as 30 min. Unlike traditional Pt-based drugs which induce cell apoptosis through DNA intercalation, carrier-platin with superior ROS catalytic activities induces a unique pattern of cancer cell death that is neither apoptosis nor ferroptosis and operates independently of DNA damage. Importantly, carrier-platin demonstrates superior anti-tumor efficacy against a broad spectrum of cancers, particularly those with multidrug resistance, while maintaining minimal systemic toxicity. Our findings reveal a distinct mechanism of action of Pt in cancer cell eradication, positioning carrier-platin as a novel category of anti-cancer chemotherapeutics.

In situ self-assembly of artesunate-β-cyclodextrin supramolecular nanomedicine as potential anti-cancer prodrug

Supramolecular nanomedicines have drawn great interest in cancer therapy, but their potential immunotoxicities restrict application in clinical translation. Herein, we constructed a supramolecular nanomedicine CD-Artesunate (CD-ATS) in situ by supramolecular polymerization and orthogonal self-assembly. The nanostructure was meticulously characterized using 1D and 2D Nuclear Magnetic Resonance (NMR) spectroscopy, Mass spectrometry, Transmission Electron Microscopy (TEM), and particle size distribution analysis. β-cyclodextrin (β-CD) hosts are conjugated with artesunate (ATS) by click chemistry to improve the solubility and antitumor activity of ATS. Supramolecular nanomedicine was prepared through orthogonal self-assembly driven by host−guest complexation and hydrogen bonds. The results showed that the aqueous solubility of CD-ATS was 30 times better than that of free ATS. Furthermore, CD-ATS displayed a superior antitumor effect against HCT116 tumor cells compared to the first-line drug Taxol. This enhanced effect was attributed to the induction of excessive reactive oxygen species (ROS) generation, which subsequently triggered apoptosis.

Disruption of Poly(ADP-ribosyl)ation Improves Plant Tolerance to Methyl Viologen-Mediated Oxidative Stress via Induction of ROS Scavenging Enzymes.

ADP-ribosylation (ADPRylation) is a mechanism which post-translationally modifies proteins in eukaryotes in order to regulate a broad range of biological processes including programmed cell death, cell signaling, DNA repair, and responses to biotic and abiotic stresses. Poly(ADP-ribosyl) polymerases (PARPs) play a key role in the process of ADPRylation, which modifies target proteins by attaching ADP-ribose molecules. Here, we investigated whether and how PARP1 and PARylation modulate responses of Nicotiana benthamiana plants to methyl viologen (MV)-induced oxidative stress. It was found that the burst of reactive oxygen species (ROS), cell death, and loss of tissue viability invoked by MV in N. benthamiana leaves was significantly delayed by both the RNA silencing of the PARP1 gene and by applying the pharmacological inhibitor 3-aminobenzamide (3AB) to inhibit PARylation activity. This in turn reduced the accumulation of PARylated proteins and significantly increased the gene expression of major ROS scavenging enzymes including SOD (NbMnSOD; mitochondrial manganese SOD), CAT (NbCAT2), GR (NbGR), and APX (NbAPX5), and inhibited cell death. This mechanism may be part of a broader network that regulates plant sensitivity to oxidative stress through various genetically programmed pathways.

Bis(thiosemicarbazide)gallium(III) Complexes as Potent Anticancer Agents by ROS Induction and Mitochondrial Pathway Activation

ABSTRACTA series of bis(thiosemicarbazide)gallium (III) complexes were synthesized and characterized by infrared spectroscopy, mass spectrometry, nuclear magnetic resonance, single‐crystal x‐ray crystallography, and density functional theory (DFT) calculation. The cytotoxicity of these gallium(III) complexes (CP 1–4) was subsequently evaluated against HCT‐116, HeLa, MDA‐MB‐231, and A549 cancer cell lines, as well as the normal cell line LO2, by MTT assays. The results indicated that CP‐1 displayed potent inhibitory effects against human colorectal cancer cells (HCT‐116) (IC50 = 0.03 ± 0.01) and human breast cancer cells (MDA‐MB‐231) (IC50 = 0.02 ± 0.01), significantly outperforming cisplatin. Moreover, CP‐2 exhibited notable selectivity towards MDA‐MB‐231 cells (IC50 = 5.01 ± 0.40) with minimal toxicity towards normal cells. Mechanistic studies revealed that treatment with CP 1–2 led to elevated intracellular reactive oxygen species (ROS) levels, resulting in cell cycle arrest at different phases. Specifically, CP‐1 induced G2/M phase arrest, inhibiting cancer cell proliferation, whereas CP‐2 hindered DNA synthesis (S phase) to impede cell proliferation. Furthermore, both CP‐1 and CP‐2 caused a reduction in mitochondrial membrane potential, activating the mitochondrial apoptotic pathway and inducing apoptosis in cancer cells. Molecular docking experiments demonstrated strong interactions between CP 1–2 and protein disulfide isomerase (PDI) at the molecular level. These findings suggest that CP‐1 and CP‐2 serve as potential anticancer agents, particularly showing promising potential in the treatment of breast cancer.

The biological activity of bacterial rhamnolipids on Arabidopsis thaliana and the cyst nematode Heterodera schachtii is linked to their molecular structure

Rhamnolipids (RLs) are amphiphilic compounds of bacterial origin that offer a broad range of potential applications as biosurfactants in industry and agriculture. They are reported to be active against different plant pests and pathogens and thus are considered promising candidates for nature-derived plant protection agents. However, as these glycolipids are structurally diverse, little is known about their exact mode of action and, in particular, the relation between molecular structure and biological activity against plant pests and pathogens.Engineering the synthesis pathway in recombinant Pseudomonas putida strains in combination with advanced HPLC techniques allowed us to separately analyze the activities of mixtures of pure mono-RLs (mRLs) and of pure di-RL (dRLs), as well as the activity of single congeners. In a model system with the plant Arabidopsis thaliana and the plant-parasitic nematode (PPN) Heterodera schachtii we demonstrate that RLs can significantly reduce infection, whereas their impact on the host plant varied depending on their molecular structure. While mRLs reduced plant growth even at a low concentration, dRLs showed a neutral to beneficial impact on plant development. Treating plants with dRLs triggered an increased reactive oxygen species (ROS) production, indicating the activation of stress-response signaling and possibly plant defense. Pretreatment of plants with mRLs or dRLs prior to application of flagellin (flg22), a known ROS inducer, further increased the ROS response to flg22. While dRLs stimulated an elevated flg22-induced ROS peak, a pretreatment with mRLs resulted in a prolonged synthesis of ROS indicating a generally elevated stress level. Neither mRLs nor dRLs induced the expression of plant defense marker genes of salicylic acid, jasmonic acid, and ethylene pathways.Detailed studies on dRLs revealed that even high concentrations up to 755 ppm of these molecules have no lethal impact on H. schachtii infective juveniles. Infection assays with individual dRL congeners showed that the C10-C8 acyl chained dRL was the only congener without effect, while dRLs with C10-C12 and C10-C12:1 acyl chains were most efficient in reducing nematode infection even at concentrations below 2 ppm. As determined by phenotyping and ROS measurements, A. thaliana reacted more sensitive to long-chained dRLs in a concentration-dependent manner.Our experiments show a clear structure-activity relation for the effect of RLs on plants. In conclusion, functional assessment and analysis of the mode of action of RLs in plants and other organisms require careful consideration of their molecular structure and composition.

The anti-cancer mechanism of Celastrol by targeting JAK2/STAT3 signaling pathway in gastric and ovarian cancer

BackgroundCelastrol is a natural triterpene exhibiting significant and extensive antitumor activity in a wide range of cancer. Due to unfavorable toxicity profile and undefined mechanism, Celastrol's application in clinical cancer therapy remains limited. Herein, we elucidate the pharmacological mechanism of Celastrol's anticancer effects, with a focus on STAT3 signaling pathway in cancers with high incidence of metastasis. MethodsThe safety profile of Celastrol were assessed in mice. In vitro analysis was performed in gastric cancer and ovarian cancer to assess the cytotoxicity, induction of reactive oxygen species (ROS) of Celastrol using STAT3 knockout cancer cells. Effects of Celastrol on STAT3 activation and transcription activity, JAK2/STAT3 signaling protein expression were assessed. Additionally, proteomic contrastive analysis was performed to explore the molecular association of Celastrol with STAT3 deletion in cancer cells. ResultsCelastrol has no obvious toxic effect at 1.5 mg/kg/day in a 15 days' administration. Celastrol inhibits tumor growth and increases ROS in a STAT3 dependent manner in gastric and ovarian cancer celllines. On molecular level, it downregulates IL-6 level and inhibits the JAK2/STAT3 signaling pathway by suppressing STAT3’ activation and transcription activity. Proteomic contrastive analysis suggests a similar cellular mechanism of action between Celastrol and STAT3 deletion on regulating cancer progression pathways related to migration and invasion. ConclusionOur research elucidates the anti-cancer mechanism of Celastrol through targeting the JAK2/STAT3 signaling pathway in cancer with high incidence of metastasis. This study provides a solid theoretical basis for the application of Celastrol in cancer therapy.

Is Cadmium Genotoxicity Due to the Induction of Redox Stress and Inflammation? A Systematic Review.

The transition metal cadmium (Cd) is toxic to humans and can induce cellular redox stress and inflammation. Cd is a recognized carcinogen, but the molecular mechanisms associated with its genotoxicity and carcinogenicity are not defined. Therefore, a systematic review was undertaken to examine the scientific literature that has covered the molecular mechanism of Cd genotoxicity and its relationship to cellular redox stress and inflammation. An electronic database search of PubMed, Scopus, and the Web of Science Core Collection was conducted to retrieve the studies that had investigated if Cd genotoxicity was directly linked to the induction of redox stress and inflammation. Studies included exposure to Cd via in vitro and in vivo routes of administration. Of 214 publications retrieved, 10 met the inclusion criteria for this review. Preclinical studies indicate that Cd exposure causes the induction of reactive oxygen species (ROS) and, via concomitant activity of the transcription factor NF-κβ, induces the production of pro-inflammatory cytokines and a cytokine profile consistent with the induction of an allergic response. There is limited information regarding the impact of Cd on cellular signal transduction pathways, and the relationship of this to genotoxicity is still inconclusive. Nevertheless, pre-incubation with the antioxidants, N-acetylcysteine or sulforaphane, or the necroptosis inhibitor, necrostatin-1, reduces Cd toxicity; indicative that these agents may be a beneficial treatment adjunct in cases of Cd poisoning. Collectively, this review highlights that Cd-induced toxicity and associated tissue pathology, and ultimately the carcinogenic potential of Cd, may be driven by redox stress and inflammatory mechanisms.

Nrf2-Mediated Antioxidant Response and Drug Efflux Transporters Upregulation as Possible Mechanisms of Resistance in Photodynamic Therapy of Cancers.

Photodynamic therapy (PDT) is a groundbreaking approach involving the induction of cytotoxic reactive oxygen species (ROS) within tumors through visible light activation of photosensitizers (PS) in the presence of molecular oxygen. This innovative therapy has demonstrated success in treating various cancers. While PDT proves highly effective in most solid tumors, there are indications that certain cancers exhibit resistance, and some initially responsive cancers may develop intrinsic or acquired resistance to PDT. The molecular mechanisms underlying this resistance are not fully understood. Recent evidence suggests that, akin to other traditional cancer treatments, the activation of survival pathways, such as the KEAP1/Nrf2 signaling pathway, is emerging as an important mechanism of post-PDT resistance in many cancers. This article explores the dual role of Nrf2, highlighting evidence linking aberrant Nrf2 expression to treatment resistance across a range of cancers. Additionally, it delves into the specific role of Nrf2 in the context of photodynamic therapy for cancers, emphasizing evidence that suggests Nrf2-mediated upregulation of antioxidant responses and induction of drug efflux transporters are potential mechanisms of resistance to PDT in diverse cancer types. Therefore, understanding the specific role(s) of Nrf2 in PDT resistance may pave the way for the development of more effective cancer treatments using PDT.

The role of N6-methyladenosine RNA methylation in the crosstalk of circadian clock and neuroinflammation in rodent suprachiasmatic nuclei.

N6-methyladenosine (m6A) is the most abundant epitranscriptomic mark that regulates the fate of RNA molecules. Recent studies have revealed a bidirectional interaction between m6A modification and the circadian clock. However, the precise temporal dynamics of m6A global enrichment in the central circadian pacemaker have not been fully elucidated. Our study investigates the relationship between FTO demethylase and molecular clocks in primary cells of the suprachiasmatic nucleus (SCN). In addition, we examined the effects of lipopolysaccharide (LPS) on Fto expression and the role of FTO in LPS-induced reactive oxygen species (ROS) production in primary SCN cell culture. We observed circadian rhythmicity in the global m6A levels, which mirrored the rhythmic expression of the Fto demethylase. Silencing FTO using siRNA reduced the mesor of Per2 rhythmicity in SCN primary cells and extended the period of the PER2 rhythm in SCN primary cell cultures from PER2::LUC mice. When examining the immune response, we discovered that exposure to LPS upregulated global m6A levels while downregulating Fto expression in SCN primary cell cultures. Interestingly, we found a loss of circadian rhythmicity in Fto expression following LPS treatment, indicating that the decrease of FTO levels may contribute to m6A upregulation without directly regulating its circadian rhythm. To explore potential protective mechanisms against neurotoxic inflammation, we examined ROS production following LPS treatment in SCN primary cell cultures pretreated with FTO siRNA. We observed a time-dependent pattern of ROS induction, with significant peak at 32 h but not at 20 h after synchronization. Silencing the FTO demethylase abolished ROS induction following LPS exposure, supporting the hypothesis that FTO downregulation serves as a protective mechanism during LPS-induced neuroinflammation in SCN primary cell cultures.

Kinetics and toxicity of nanoplastics in ex vivo exposed human whole blood as a model to understand their impact on human health

The ubiquitous presence of nanoplastics (NPLs) in the environment is considered of great health concern. Due to their size, NPLs can cross both the intestinal and pulmonary barriers and, consequently, their presence in the blood compartment is expected. Understanding the interactions between NPLs and human blood components is required. In this study, to simulate more adequate real exposure conditions, the whole blood of healthy donors was exposed to five different NPLs: three polystyrene NPLs of approximately 50 nm (aminated PS-NH2, carboxylated PS-COOH, and pristine PS- forms), together with two true-to-life NPLs from polyethylene terephthalate (PET) and polylactic acid (PLA) of about 150 nm. Internalization was determined in white blood cells (WBCs) by confocal microscopy, once the different main cell subtypes (monocytes, polymorphonucleated cells, and lymphocytes) were sorted by flow cytometry. Intracellular reactive oxygen species (iROS) induction was determined in WBCs and cytokine release in plasma. In addition, hemolysis, coagulation, and platelet activation were also determined. Results showed a differential uptake between WBC subtypes, with monocytes showing a higher internalization. Regarding iROS, lymphocytes were those with higher levels, which was observed for different NPLs. Changes in cytokine release were also detected, with higher effects observed after PLA- and PS-NH2-NPL exposure. Hemolysis induction was observed after PS- and PS-COOH-NPL exposure, but no effects on platelet functionality were observed after any of the treatments. To our knowledge, this is the first study comprehensively evaluating the bloodstream kinetics and toxicity of NPL from different polymeric types on human whole blood, considering the role played by the cell subtype and the NPLs physicochemical characteristics in the effects observed after the exposures.

The role of reactive oxygen species in gastric cancer.

Gastric cancer (GC) ranks fifth in cancer incidence and fourth in cancer-related mortality worldwide. Reactive oxygen species (ROS) are highly oxidative oxygen-derived products that have crucial roles in cell signaling regulation and maintaining internal balance. ROS are closely associated with the occurrence, development, and treatment of GC. This review summarizes recent findings on the sources of ROS and the bidirectional regulatory effects on GC and discusses various treatment modalities for GC that are related to ROS induction. In addition, the regulation of ROS by natural small molecule compounds with the highest potential for development and applications in anti-GC research is summarized. The aim of the review is to accelerate the clinical application of modulating ROS levels as a therapeutic strategy for GC.