Radical Oxygen Species Production Research Articles

P-399 Beyond chromosome screening: The impact of progesterone and in vitro oxidative stress on failed euploid blastocyst transfers

Abstract Study question To assess the effect of serum progesterone levels on the production of radical oxygen species (ROS) by endometrial immune cells in patients with non-genetic miscarriages. Summary answer Elevated serum pre-transfer progesterone levels favour the development of an endometrial microenvironment that is not conducive to a healthy pregnancy, by increasing ROS production. What is known already Endometrial immune cells, especially uterine Natural Killer (uNK) cells, play an essential role in the proper development of pregnancy, promoting angiogenesis and adequate placentation. The maturation of these cells is indirectly determined by progesterone levels, which, during the secretory phase, enhance the synthesis of key cytokines for uNKs’ functionality. Previous studies have already indicated that increases in progesterone levels during the follicular phase can alter the endometrial microenvironment, affecting its receptivity. However, the molecular effect that imbalances of this hormone may have on the endometrium on the day of embryo transfer and directly in relation to uNK is still unknown. Study design, size, duration We conducted a prospective exploratory study, between September 2022 and January 2024, including 15 patients with previous miscarriages after euploid single embryo transfer (SET), ruling out the genetic cause for such gestational losses. We obtained endometrial biopsies of all patients, after 5 days of progesterone, in a cycle with hormone replacement therapy. The same day of the biopsy, serum progesterone levels were measured in all the patients included. Participants/materials, setting, methods In vitro cultures enriched in uNK cells (CD56+CD16-) were established from the patients’ endometrial biopsies and cell enrichment was confirmed by flow cytometry. These cells were co-cultured with the JEG-3 cell line (placental cells), simulating the microenvironment of early pregnancy. Cellular ROS production was measured by fluorescence detection 40 hours post-culture using a commercial kit. A linear regression model was used to determine statistically significant correlations (p < 0.05) between ROS and progesterone levels. Main results and the role of chance The mean age of the participating patients was 38.9 years and the BMI was 23.2 kg/m2. The mean progesterone level the day of the biopsy was 15.6 ng/ml. The cell cultures obtained from patients were successfully enriched in the desired cell population, with an average percentage of 89.6% uNK cells (CD56+CD16-) of total leukocytes (CD45+) obtained by flow cytometry. After culturing the same number of cells from each patient with the same number of spheroids of the JEG-3 cell line, an average ROS production of 31341.2 arbitrary units (a.u.) was obtained. Taking into account the co-cultures stablished from the 15 patients, a positive correlation between cellular ROS production and progesterone level was observed (r = 0.6728, p = 0.006). Limitations, reasons for caution Although the results shown may provide clues about the molecular dynamics of the endometrium during early pregnancy, they should be taken with caution, as it is not yet known whether this progesterone elevation is the cause or rather the consequence of an unfavourable endometrial microenvironment with high oxidative stress. Wider implications of the findings This study provides new information on the endometrial microenvironment of patients suffering non-genetic miscarriages and, although much remains to be studied, this association between hormone levels and oxidative stress may point the way to future studies investigating a possible explanation for these undesirable reproductive outcomes. Trial registration number Not Applicable

DMAR drug loaded in enzymatic poly-l-phenylalanine nanotubes reduce inflammation and cytotoxicity in human synoviocytes

We investigated the release of chloroquine (Clq) as a model DMAR drug encapsulated in enzyme-mediated polyphenylalanine nanotubes (Clq-Nt) using primary cultures of synovial cells from OA inpatients undergoing total knee replacement. The Clq-Nts were also embedded in an injectable vehicle containing hyaluronic acid (Clq-Nt-HA). Clq-Nt and Clq-Nt-HA samples reduced 62 and 37.5 % the concentration of IL-1β, respectively. For TNF-α the reduction was 38 and 26 %, and for IL-6 was 17.1 and 10 % for Clq-Nt and Clq-Nt-HA, respectively. Additionally, Clq-Nt and Clq-Nt-HA allowed cell viability and proliferation of the synoviocytes according to MTT and CaAM/EthD-1 assays after fifteen days exposure. Micrographs of crystal violet assay also assess the adequate morphologies for synoviocytes treated with Clq-loaded in the tubes. The production of intracellular radical oxygen species (ROS), and extracellular H2O2 and nitrites was also investigated with the inpatient synoviocyte cells with and without treatments which showed no significant differences. Additionally, the apparent viscosity with the shear rate and viscoelastic properties in the injectable fluid containing the encapsulated drug Clq-Nt-HA showed no significant variation with control viscous fluid with only HA, and it falls within the synovial fluid viscosity range for arthritis patients.

Molecular docking analysis of chlorpyrifos at the human α7-nAChR and its potential relationship with neurocytoxicity in SH-SY5Y cells

The organophosphate insecticide chlorpyrifos (CPF), an acetylcholinesterase inhibitor, has raised serious concerns about human safety. Apart from inducing synaptic acetylcholine accumulation, CPF could also act at nicotinic acetylcholine receptors, like the α7-isoform (α7-nAChR), which could potentially be harmful to developing brains. Our aims were to use molecular docking to assess the binding interactions between CPF and α7-nAChR through, to test the neurocytotoxic and oxidative effects of very low concentrations of CPF on SH-SY5Y cells, and to hypothesize about the potential mediation of α7-nAChR. Docking analysis showed a significant binding affinity of CPH for the E fragment of the α7-nAChR (ΔGibbs: −5.63 to −6.85 Kcal/mol). According to the MTT- and Trypan Blue-based viability assays, commercial CPF showed concentration- and time-dependent neurotoxic effects at a concentration range (2.5–20 µM), ten-folds lower than those reported to have crucial effects for sheer CPF. A rise of the production of radical oxygen species (ROS) was seen at even lower concentrations (1–2.5 µM) of CPF after 24h. Notably, our docking analysis supports the antagonistic actions of CPF on α7-nAChR that were recently published. In conclusion, while α7-nAChR is responsible for neuronal survival and neurodevelopmental processes, its activity may also mediate the neurotoxicity of CPF.

Sunscreen Safety and Efficacy for the Prevention of Cutaneous Neoplasm.

Sunscreen is widely used for ultraviolet radiation protection. Studies validate sun protection factors (SPFs) to prevent ultraviolet (UV)-induced skin changes such as melanoma and squamous cell carcinoma (SCC). Few studies examine sunscreen's impact on endocrine and immune system dysregulation, the production of radical oxygen species, and whether the ingredients deteriorate under prolonged exposure. We present an investigation of sunscreen labels and how ingredients impact sun safety and human health. A review of the literature was conducted using Embase and PubMed to examine sunscreen safety, efficacy, and use to prevent UV-induced skin damage. Increasing sunscreen reapplication, wearing protective clothing, and limiting exposure can reduce the incidence of skin cancer. Inorganic sunscreens form barriers to block UV light, but without titanium dioxide (TiO2), they may not be advantageous due to their low UVA protection. Organic sunscreens absorb into the skin and provide a better feeling after application. Octocrylene and avobenzone are stable and provide UVA and UVB protection with minimal adverse effects. Oxybenzone is harmful to the neuroendocrine system and should be avoided. Titanium dioxide works for broad-spectrum UV protection and offers minimal adverse effects. Octocrylene and avobenzone are organic sunscreen ingredients that also provide a better feeling on the skin after application, which enables higher rates of use. Oxybenzone should be avoided.

P007 Neutrophil function in lesional biopsies is a strong determinant of IBD severity and may relate to an altered functional state already present in circulating cells

Abstract Background Neutrophils clear luminal bacteria from the intestinal lamina propria and have a protective role in Inflammatory Bowel Disease (IBD). However, their production of inflammatory cytokines, matrix metalloproteases and radical oxygen species causes irreversible tissue damage. Histological assessment of infiltrating neutrophils and indirect measurement of neutrophil-derived calprotectin in feces are used to assess disease severity in patients. Since IBD is a heterogeneous disease in terms of presentation, severity and course, we hypothesize that different patients have a different composition of their neutrophil compartment that leads to a different balance between protection and damage. We aim to study the variability in neutrophil phenotype and function and relate it to patient heterogeneity. Methods We analyzed endoscopic biopsies and peripheral blood samples from children diagnosed with IBD within the PIBD-SETQ cohort. Paired biopsies obtained at diagnosis were scored by a pathologist and analyzed by IHC and RNAseq. RNAseq was also performed on purified circulatory neutrophil at diagnosis and their phenotype was analyzed by whole-blood flow cytometry. Results At diagnosis, high numbers of infiltrating neutrophils in intestinal tissue differentiated IBD patients with high clinical disease activity, more severe endoscopic and histological disease and high plasma concentrations of IL-17. RNA sequencing of lesional intestinal biopsies revealed differential expression of genes linked to neutrophil degranulation and IL-17 signaling in the colon of IBD patients with high neutrophil infiltration. Moreover, these biopsies had high mRNA expression for Oncostatin M, a neutrophil product known to associate with therapy resistance. To assess whether circulating neutrophils were altered in IBD before entering the intestinal tissue, we performed bulk RNAseq analysis of purified circulating neutrophils from non-IBD and CD patients. Neutrophils from CD patients had increased expression of genes related to granule formation and filling (MMP9, S100A8, S100A9) and pathogen sensing (TLR5, NLRC4) but not cytokine production (IL1B, OSM), relative to non-IBD patients. Expression of CD10 was decreased in circulating neutrophils from UC and CD patients while CD16 expression was lower in UC-derived neutrophils, suggesting these cells have a more immature state. Conclusion We have detected changes in the maturity of neutrophils in the circulation of some IBD patients that could have functional consequences in terms of bacterial clearance and tissue damage in the intestinal mucosa. Uncovering different functional profiles in neutrophils may help dissect patient heterogeneity and provide novel targets for therapy.

Obesity Correlates with Chronic Inflammation of the Innate Immune System in Preeclampsia and HELLP Syndrome during Pregnancy.

HELLP syndrome is characterized by hemolysis, elevated liver enzymes, and a low platelet count and poses an increased risk to the pregnant woman and the unborn child. Individual risk factors such as obesity may alter immunocompetence and influence the course of preeclampsia (PE) or HELLP syndrome. Blood samples were collected from 21 pregnant women (7 healthy, 6 with PE, and 8 with HELLP syndrome) and polymorphonuclear neutrophils (PMNs) were subsequently isolated. Production of radical oxygen species (ROS), cell movement, and NETosis were assessed by live-cell imaging. Surface protein expression and oxidative burst were analyzed by flow cytometry. PE and HELLP patients had significantly higher BMI compared to the healthy control group. Depending on the expression of CD11b, CD62L, and CD66b on PMNs, a surface protein activation sum scale (SPASS) was calculated. PMNs from patients with high SPASS values showed prolonged and more targeted migration with delayed ROS production and NETosis. Obesity is associated with a chronic inflammatory state, which in combination with immunological triggers during pregnancy could modulate PMN functions. Pregnant women with higher BMI tend to have higher SPASS values, indicating activation of the innate immune system that could co-trigger PE or HELLP syndrome.

SYNOVIAL FLUID NEUTROPHILS PLAY A ROLE IN THE PATHOPHYSIOLOGY OF KNEE OSTEOARTHRITIS: A PHENOTYPIC AND FUNCTIONAL STUDY

An increased number of neutrophils (NEUs) has long been associated with infections in the knee joints; their contribution to knee osteoarthritis (KOA) pathophysiology remains largely unexplored. This study aimed to compare the phenotypic and functional characteristics of synovial fluid (SF)-derived NEUs in KOA and knee infection (INF).Flow cytometric analysis, protein level measurements (ELISA), NEU oxidative burst assays, detection of NEU phagocytosis (pHrodoTM Green Zymosan BiparticlesTM Conjugate for Phagocytosis), morphological analysis of the SF-derived/synovial tissue NEUs, and cultivation of human umbilical vein endothelial cells (HUVECs) using SF supernatant were used to characterise NEUs functionally/morphologically.Results: Compared with INF NEUs, KOA NEUs were characterised by a lower expression of CD11b, CD54 and CD64, a higher expression of CD62L, TLR2 and TLR4, and lower production of inflammatory mediators and proteases, except CCL2.Functionally, KOA NEUs displayed an increased production of radical oxygen species and phagocytic activity compared with INF NEUs. Morphologically, KOA and INF cells displayed different cell sizes and morphology, histological characteristics of the surrounding synovial tissues and influence on endothelial cells. KOA NEUs were further subdivided into two groups: SF containing <10% and SF with 10%–60% of NEUs. Analyses of two KOA NEU subgroups revealed that NEUs with SF <10% were characterised by 1) higher CD54, CD64, TLR2 and TLR4 expression on their surface; 2) higher concentrations of TNF-α, sTREM-1, VILIP-1, IL-1RA and MMP-9 in SFs.Our findings reveal a key role for NEUs in the pathophysiology of KOA, indicating that these cells are morphologically and functionally different from INF NEUs. Further studies should explore the mechanisms that contribute to the increased number of NEUs and their crosstalk with other immune cells in KOA.This study was supported by the Ministry of Health of the Czech Republic (NU20-06-00269; NU21-06-00370).

Effect of Ferric Carboxymaltose Supplementation in Patients with Heart Failure with Preserved Ejection Fraction: Role of Attenuated Oxidative Stress and Improved Endothelial Function.

Both clinical and experimental evidence shows that iron deficiency (ID) correlates with an increased incidence of heart failure (HF). Moreover, data on iron supplementation demonstrating a beneficial effect in subjects with HF have mostly been collected in patients undergoing HF with reduced ejection fraction (HFrEF). Relatively poor data, however, exist on the potential of iron supplementation in patients with HF with preserved ejection fraction (HFpEF). Here, we report on data emerging from a multicentric, double-blind, randomized, placebo-controlled study investigating the effect of IV supplementation with a placebo or ferric carboxymaltose (FCM) on 64 subjects with HFpEF. ID was detected by the measurement of ferritin levels. These data were correlated with cardiac performance measurements derived from a 6 min walking test (6MWT) and with echocardiographic determinations of diastolic function. Moreover, an EndoPAT analysis was performed to correlate cardiac functionality with endothelial dysfunction. Finally, the determination of serum malondialdehyde (MDA) was performed to study oxidative stress biomarkers. These measurements were carried out before and 8 weeks after starting treatment with a placebo (100 mL of saline given i.v. in 10 min; n = 32) or FCM at a dose of 500 mg IV infusion (n = 32), which was given at time 0 and repeated after 4 weeks. Our data showed that a condition of ID was more frequently associated with impaired diastolic function, worse 6MWT and endothelial dysfunction, an effect that was accompanied by elevated MDA serum levels. Treatment with FCM, compared to the placebo, improved ferritin levels being associated with an improved 6MWT, enhanced cardiac diastolic function and endothelial reactivity associated with a significant reduction in MDA levels. In conclusion, this study confirmed that ID is a frequent comorbidity in patients with HFpEF and is associated with reduced exercise capacity and oxidative stress-related endothelial dysfunction. Supplementation with FCM determines a significant improvement in diastolic function and the exercise capacity of patients with HFpEF and is associated with an enhanced endothelial function and a reduced production of oxygen radical species.

Incorporating Mitochondrial Gene Expression Changes Within a Testable Mathematical Model for Alzheimer's Disease: Stress Response Modulation Predicts Potential Therapeutic Targets.

Alzheimer's disease is a specific form of dementia characterized by the aggregation of amyloid-β plaques and tau tangles. New research has found that the formation of these aggregates occurs after dysregulation of cellular respiration and the production of radical oxygen species. Proteomic data shows that these changes are also related to unique gene expression patterns. This study is designed to incorporate both proteomic and gene expression data into a testable mathematical model for AD. Manipulation of this new model allows the identification of potential therapeutic targets for AD. We investigate the impact of these findings on new therapeutic targets via metabolic flux analysis of sirtuin stress response pathways while also highlighting the importance of metabolic enzyme activity in maintaining proper respiratory activity. Our results indicate that protective changes in SIRT1 and AMPK expression are potential avenues for therapeutics. Combining our mitochondrial gene expression analyses with available protein data allowed the construction of a new mathematical model for AD that provides a useful approach to test the efficacy of potential AD therapeutic targets.

Decrypting the Influence of Axial Coordination on the Electronic Microenvironment of Co-N 5 Site for Enhanced Electrocatalytic Reaction

Decrypting the Influence of Axial Coordination on the Electronic Microenvironment of Co-N ₅ Site for Enhanced Electrocatalytic Reaction

The Pro-Inflammatory Deletion Allele of the NF-κB1 Polymorphism Is Characterized by a Depletion of Subunit p50 in Sepsis.

The functionally important NF-κB1 promoter polymorphism (−94ins/delATTG) significantly shapes inflammation and impacts the outcome of sepsis. However, exploratory studies elucidating the molecular link of this genotype-dependent pattern are lacking. Accordingly, we analyzed lipopolysaccharide-stimulated peripheral blood mononuclear cells from both healthy volunteers (n = 20) and septic patients (n = 10). All individuals were genotyped for the −94ins/delATTG NF-κB1 promoter polymorphism. We found a diminished nuclear activity of the NF-κB subunit p50 in ID/DD genotypes after 48 h of lipopolysaccharide stimulation compared to II genotypes (p = 0.025). This was associated with higher TNF-α (p = 0.005) and interleukin 6 concentrations (p = 0.014) and an increased production of mitochondrial radical oxygen species in ID/DD genotypes (p = 0.001). Although ID/DD genotypes showed enhanced activation of mitochondrial biogenesis, they still had a significantly diminished cellular ATP content (p = 0.046) and lower mtDNA copy numbers (p = 0.010) compared to II genotypes. Strikingly, these findings were mirrored in peripheral blood mononuclear cells taken from septic patients. Our results emphasize the crucial aspect of considering NF-κB subunits in sepsis. We showed here that the deletion allele of the NF-κB1 (−94ins/delATTG) polymorphism was associated with the lower nuclear activity of subunit p50, which, in turn, was associated with aggravated inflammation and mitochondrial dysfunction.

Photodynamic action of photosensitizers based on polycationic derivatives of synthetic bacteriochlorin against human lung cancer cells A549

In view of their potential in the treatment of oncological diseases, photosensitizers (PS) have been the object of active research for the last years. The applied therapeutic photodynamic method involves the activation of a PS by light at a specific wavelength. PS interacts with oxygen and catalyzes the production of singlet oxygen molecules or radical oxygen species which leads to tumor cell death. This work is devoted to the study of the effectiveness of the photodynamic action of new PSs based on polycationic derivatives of synthetic bacteriochlorin on human lung cancer cells A549. The results obtained show that these PS effectively bind to these cells, have high phototoxicity and low ‘dark’ cytotoxicity for them. Morphological and immunohistochemical studies show that photodynamic effect leads to induction of cell necrosis and apoptosis, as well as a sharp decrease in mitotic activity.

Kv7.4 channels regulate potassium permeability in neuronal mitochondria

Mitochondrial K+ permeability regulates neuronal apoptosis, energy metabolism, autophagy, and protection against ischemia–reperfusion injury. Kv7.4 channels have been recently shown to regulate K+ permeability in cardiac mitochondria and exert cardioprotective effects. Here, the possible expression and functional role of Kv7.4 channels in regulating membrane potential, radical oxygen species (ROS) production, and Ca2+ uptake in neuronal mitochondria was investigated in both clonal (F11 cells) and native brain neurons.In coupled mitochondria isolated from F11 cells, K+-dependent changes of mitochondrial membrane potential (ΔΨ) were unaffected by the selective mitoBKCa channel blocker iberiotoxin and only partially inhibited by the mitoKATP blockers glyburide or ATP. Interestingly, K+-dependent ΔΨ decrease was significantly reduced by the Kv7 blocker XE991 and enhanced by the Kv7 activator retigabine. Among Kv7s, western blot experiments showed the expression of only Kv7.4 subunits in F11 mitochondrial fractions; immunocytochemistry experiments showed a strong overlap between the Kv7.4 fluorescent signal and that of the mitochondrial marker Mitotracker. Silencing of Kv7.4 expression significantly suppressed retigabine-dependent decrease in ΔΨ in intact F11 cells. Expression of Kv7.4 subunits was also detected by western blot in isolated mitochondria from total mouse brain and by immunofluorescence in mouse primary cortical neurons. Pharmacological experiments revealed a relevant functional role for Kv7.4 channels in regulating membrane potential and Ca2+ uptake in isolated neuronal mitochondria, as well as ΔΨ and ROS production in intact cortical neurons. In conclusion, these findings provide the first experimental evidence for the expression of Kv7.4 channels and their contribution in regulating K+ permeability of neuronal mitochondria.

Antioxidant and Anti-Inflammatory Activity of Combined Phycocyanin and Palmitoylethanolamide in Human Lung and Prostate Epithelial Cells

Inflammation involving the innate and adaptive immune systems is a normal response to infection; however, when allowed to continue unchecked, inflammation may result in several pathologies. Natural molecules with antioxidant properties can target the key players of inflammation and exert beneficial health effects. In this study, human normal bronchial (Beas-2B) and prostate (HPrEpiC) epithelial cell lines were exposed to infectious stimulation and treated with phycocyanin (PC) and palmitoylethanolamide (PEA), with the aim of demonstrating the enhanced antioxidant and anti-inflammatory properties of the combination. The cotreatment protected from cytotoxicity and greatly abated both the production of radical oxygen species (ROS) and the transcription of several inflammatory cytokines. Oxidative stress and inflammation were curtailed by affecting three main pathways: (1) inhibition of cyclooxygenase-2 enzyme and consequent decrease of signaling generating ROS; (2) increased synthesis of glutathione and therefore strengthening of the natural antioxidant defenses of the cells; (3) decreased infection-driven mitochondrial respiratory burst which generates oxidative stress. Based on the mounting interest in using nutraceuticals as adjuvants in the clinical practice, the present study unveils new mechanisms of action and enhanced efficacy of PC and PEA, supporting the possible exploitation of this combination in human disorders.

Evolutionary impacts of purine metabolism genes on mammalian oxidative stress adaptation.

Many mammals risk damage from oxidative stress stemming from frequent dives (i.e., cycles of ischemia/reperfusion and hypoxia/reoxygenation), high altitude and subterranean environments, or powered flight. Purine metabolism is an essential response to oxidative stress, and an imbalance between purine salvage and de novo biosynthesis pathways can generate damaging reactive oxygen species (ROS). Here, we examined the evolution of 117 purine metabolism-related genes to explore the accompanying molecular mechanisms of enhanced purine metabolism in mammals under high oxidative stress. We found that positively selected genes, convergent changes, and nonparallel amino acid substitutions are possibly associated with adaptation to oxidative stress in mammals. In particular, the evolution of convergent genes with cAMP and cGMP regulation roles may protect mammals from oxidative damage. Additionally, 32 genes were identified as under positive selection in cetaceans, including key purine salvage enzymes (i.e., HPRT1), suggesting improved re-utilization of non-recyclable purines avoid hypoxanthine accumulation and reduce oxidative stress. Most intriguingly, we found that six unique substitutions in cetacean xanthine dehydrogenase (XDH), an enzyme that regulates the generation of the ROS precursor xanthine oxidase (XO) during ischemic/hypoxic conditions, show enhanced enzyme activity and thermal stability and diminished XO conversion activity. These functional adaptations are likely beneficial for cetaceans by reducing radical oxygen species production during diving. In summary, our findings offer insights into the molecular and functional evolution of purine metabolism genes in mammalian oxidative stress adaptations.

Chlamydomonas Responses to Salinity Stress and Possible Biotechnological Exploitation

Salinity is among the main drivers affecting growth and distribution of photosynthetic organisms as Chlamydomonas spp. These species can live in multiple environments, including polar regions, and have been frequently studied for their adaptation to live at different salinity gradients. Upon salinity stress (hypersalinity is the most studied), Chlamydomonas spp. were found to alter their metabolism, reduce biomass production (growth), chlorophyll content, photosynthetic activity, and simultaneously increasing radical oxygen species production as well as lipid and carotenoid contents. This review summarizes the current literature on salt stress related studies on the green algae from the genus Chlamydomonas considering physiological and molecular aspects. The overall picture emerging from the data suggests the existence of common features of the genus in response to salinity stress, as well as some differences peculiar to single Chlamydomonas species. These differences were probably linked to the different morphological characteristics of the studied algae (e.g., with or without cell wall) or different sampling locations and adaptations. On the other hand, molecular data suggest the presence of common reactions, key genes, and metabolic pathways that can be used as biomarkers of salt stress in Chlamydomonas spp., with implications for future physiological and biotechnological studies on microalgae and plants.

An updated overview on metal nanoparticles toxicity.

Although thousands of different nanoparticles (NPs) have been identified and synthesized to date, well-defined, consistent guidelines to control their exposure and evaluate their potential toxicity have yet to be fully established. As potential applications of nanotechnology in numerous fields multiply, there is an increased awareness of the issue of nanomaterials' toxicity among scientists and producers managing them. An updated inventory of customer products containing NPs estimates that they currently number over 5.000; ten years ago, they were one fifth of this. More often than not, products bear no information regarding the presence of NPs in the indicated list of ingredients or components. Consumers are therefore largely unaware of the extent to which nanomaterials have entered our lives, let alone their potential risks. Moreover, the lack of certainties with regard to the safe use of NPs is curbing their applications in the biomedical field, especially in the diagnosis and treatment of cancer, where they are performing outstandingly but are not yet being exploited as much as they could. The production of radical oxygen species is a predominant mechanism leading to metal NPs-driven carcinogenesis. The release of particularly reactive metal ions capable of crossing cell membranes has also been implicated in NPs toxicity. In this review we discuss the origin, behavior and biological toxicity of different metal NPs with the aim of rationalizing related health hazards and calling attention to toxicological concerns involved in their increasingly widespread use.

Highly Stable Silica-Coated Bismuth Nanoparticles Deliver Tumor Microenvironment-Responsive Prodrugs to Enhance Tumor-Specific Photoradiotherapy.

Radiosensitizers are agents capable of amplifying injury to tumor tissues by enhancing DNA damage and fortifying production of radical oxygen species (ROS). The use of such radiosensitizers in the clinic, however, remains limited by an insufficient ability to differentiate between cancer and normal cells and by the presence of a reversible glutathione system that can diminish the amount of ROS generated. Here, to address these limitations, we design an H2O2-responsive prodrug which can be premixed with lauric acid (melting point ∼43 °C) and loaded around the surface of silica-coated bismuth nanoparticles (BSNPs) for cancer-specific photoradiotherapy. Particularly, silica coating confers BSNPs with improved chemical stability against both near-infrared light and X-rays. Upon photothermal heating, lauric acid is melted to trigger prodrug release, followed by its transformation into p-quinone methide via H2O2 stimulation to irreversibly alkylate glutathione. Concurrently, this heat boosts tumor oxygenation and helps relieve the hypoxic microenvironment. Following sequential irradiation by X-rays, BSNPs generate plentiful ROS, which act in combination with these events to synergistically induce cell death via DNA breakage and mitochondria-mediated apoptosis pathways, ultimately enabling effective inhibition of tumor growth in vivo with high tumor specificity and reduced side effects. Collectively, this work presents a promising approach for the improvement of other ROS-responsive proalkylating agents, while simultaneously highlighting a robust nanosystem for combining these prodrugs with photoradiosensitizers to realize precision photoradiotherapy.

The protein-bound uremic toxin p-cresyl-sulfate promotes intracellular ROS production and lipid peroxidation in 3T3-L1 adipose cells

Patients with chronic kidney disease (CKD) often exhibit increased level of oxidative stress that contribute to the deterioration of renal function and uremic complications. White adipose tissue (WAT) has been recognized as a major site of production of radical oxygen species (ROS) in the context of metabolic diseases. This study was designed to decipher whether the protein bound uremic toxin p-cresyl-sulfate (p-CS) could contribute to ROS production in WAT and promote oxidative stress. Mouse 3T3-L1 adipocytes were incubated for 2 h in culture medium containing 212 μM p-CS, a concentration chosen to mimic levels encountered in end stage renal disease patients or KCl as a control and intracellular ROS production was measured using the fluorescent probe 5-6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate. Oxidative insult was estimated by the measurement of malondialdehyde (MDA) content and glutathione content. The effects of probenecid (1 mM) a potent inhibitor of organic anion transporter, apocynin (1 mM) an inhibitor of NADPH oxidase or common antioxidants such as α-tocopherol (2.5 μM), ascorbate (200 μM), and N-acetylcysteine (500 μM) were further evaluated. p-CS triggered a striking increase in ROS production (+228%, p < 0.01), in MDA content (+214%, p < 0.005) and a decrease in glutathione (−47%, P < 0.01). Pre-treatment of cells with probenecid, apocynin or antioxidants prevented the p-CS induced ROS production and oxidative insults. These results suggest that in uremic state, the intracellular accumulation of p-CS in adipose cells could contribute, through an activation of NADPH oxidase, to the redox imbalance often reported in CKD patients.

Proteostasis failure and mitochondrial dysfunction leads to aneuploidy-induced senescence.

Aneuploidy, an unbalanced number of chromosomes, is highly deleterious at the cellular level and leads to senescence, a stress-induced response characterized by permanent cell-cycle arrest and a well-defined associated secretory phenotype. Here, we use a Drosophila epithelial model to delineate the pathway that leads to the induction of senescence as a consequence of the acquisition of an aneuploid karyotype. Whereas aneuploidy induces, as a result of gene dosage imbalance, proteotoxic stress and activation of the major protein quality control mechanisms, near-saturation functioning of autophagy leads to compromised mitophagy, accumulation of dysfunctional mitochondria, and the production of radical oxygen species (ROS). We uncovered a role of c-Jun N-terminal kinase (JNK) in driving senescence as a consequence of dysfunctional mitochondria and ROS. We show that activation of the major protein quality control mechanisms and mitophagy dampens the deleterious effects of aneuploidy, and we identify a role of senescence in proteostasis and compensatory proliferation for tissue repair.