Cancer represents a significant threat to human health, with the use of traditional chemotherapy drugs being limited by their harsh side effects. Tumor-targeted nanocarriers have emerged as a promising solution to this problem, as they can deliver drugs directly to the tumor site, improving drug effectiveness and reducing adverse effects. However, the efficacy of most nanomedicines is hindered by poor penetration into solid tumors. Nanomotors, capable of converting various forms of energy into mechanical energy for self-propelled movement, offer a potential solution for enhancing drug delivery to deep tumor regions. External force-driven nanomotors, such as those powered by magnetic fields or ultrasound, provide precise control but often necessitate bulky and costly external equipment. Bio-driven nanomotors, propelled by sperm, macrophages, or bacteria, utilize biological molecules for self-propulsion and are well-suited to the physiological environment. However, they are constrained by limited lifespan, inadequate speed, and potential immune responses. To address these issues, nanomotors have been engineered to propel themselves forward by catalyzing intrinsic \"fuel\" in the tumor microenvironment. This mechanism facilitates their penetration through biological barriers, allowing them to reach deep tumor regions for targeted drug delivery. In this regard, this article provides a review of tumor microenvironment-activatable nanomotors (fueled by hydrogen peroxide, urea, arginine), and discusses their prospects and challenges in clinical translation, aiming to offer new insights for safe, efficient, and precise treatment in cancer therapy.

Mistakes in translation are mostly associated with toxic effects in the cell due to the production of functionally aberrant and misfolded proteins. However, under certain circumstances mistranslation can have beneficial effects and enable cells to preadapt to other stress conditions. Mistranslation may be caused by mistakes made by aminoacyl-tRNA synthetases, essential enzymes that link amino acids to cognate tRNAs. There is an Escherichia coli strain expressing isoleucyl-tRNA synthetase mutant variant with inactivated editing domain which produces mistranslated proteomes where valine (Val) and norvaline (Nva) are misincorporated into proteins instead of isoleucine. We compared this strain with the wild-type to determine the effects of such mistranslation on bacterial growth in oxidative stress conditions. When the cells were pre-incubated with 0.75 mmol/L Nva or 1.5 mmol/L Val or Nva and exposed to hydrogen peroxide, no beneficial effect of mistranslation was observed. However, when the editing-deficient strain was cultivated in medium supplemented with 0.75 mmol/L Val up to the early or mid-exponential phase of growth and then exposed to oxidative stress, it slightly outgrew the wild-type grown in the same conditions. Our results therefore show a modest adaptive effect of isoleucine mistranslation on bacterial growth in oxidative stress, but only in specific conditions. This points to a delicate balance between deleterious and beneficial effects of mistranslation.
Pogreške u translaciji uglavnom su povezane s toksičnim učincima u stanici zbog proizvodnje funkcionalno aberantnih i pogrešno smotanih proteina. Međutim, pod određenim okolnostima pogreške u translaciji mogu imati povoljne učinke i omogućiti stanicama da se prilagode drugim stresnim uvjetima. Mistranslacija može biti prouzročena pogreškama koje čine aminoacil-tRNA-sintetaze, esencijalni enzimi koji povezuju aminokiseline s pripadnim molekulama tRNA. Soj bakterije Escherichia coli koji eksprimira mutiranu inačicu izoleucil-tRNA-sintetaze s inaktiviranom domenom za popravak, proizvodi mistranslatirane proteome u kojima su valin (Val) i norvalin (Nva) pogrešno ugrađeni u proteine umjesto izoleucina. Usporedili smo ovaj soj s divljim tipom kako bismo odredili učinke takve mistranslacije na rast bakterija u uvjetima oksidacijskog stresa. Kada su stanice bile prethodno inkubirane s 0,75 mmol/L Nva ili 1,5 mmol/L Val ili Nva i potom izložene vodikovu peroksidu, nije primijećen povoljan učinak mistranslacije. Međutim, kada je soj s nedostatkom popravka pogreške uzgajan u mediju s dodatkom 0,75 mmol/L Val do rane ili srednje eksponencijalne faze rasta te potom izložen oksidacijskom stresu, prerastao je divlji tip uzgojen u istim uvjetima. Stoga naši rezultati pokazuju skroman adaptivni učinak mistranslacije izoleucina na rast bakterija u oksidacijskom stresu, ali samo u određenim uvjetima. To upućuje na osjetljivu ravnotežu između štetnih i povoljnih učinaka mistranslacije.

Durian (Durio zibethinus L.) fruit pulp is a rich source of γ-glutamylcysteine (γ-EC), a direct precursor to the antioxidant glutathione (GSH). This study elucidated the in vitro neuroprotective potential of unripe durian fruit pulp extract (UDE) against H2O2-induced neurotoxicity in SH-SY5Y cells and neuroinflammation in lipopolysaccharide (LPS)-stimulated BV-2 cells. Treatments with γ-EC, GSH standards, or UDE exhibited no cytotoxicity in SH-SY5Y and BV-2 cells, except at high concentrations. A 4-h pretreatment with 100 µM γ-EC or UDE containing 100 µM γ-EC significantly increased SH-SY5Y cell viability post H2O2 induction. Moreover, a similar pretreatment reduced LPS-stimulated production of proinflammatory cytokines in BV-2 cells. The neuroprotective effect of UDE is primarily attributed to γ-EC provision and the promotion of GSH synthesis, which in turn elevates intracellular GSH levels and reduces proinflammatory cytokines. This study identifies γ-EC in UDE as a potential neuroprotective biomarker boosting intracellular GSH levels, providing insights into UDE\'s therapeutic potential.

UNASSIGNED: This study aims to systematically evaluate the protective role of quercetin (QCT), a naturally occurring flavonoid, against oxidative damage in human endometrial stromal cells (HESCs) induced by hydrogen peroxide (H2O2). Oxidative stress, such as that induced by H2O2, is known to contribute significantly to cellular damage and has been implicated in various reproductive health issues. The study is focused on investigating how QCT interacts with specific molecular pathways to mitigate this damage. Special attention was given to the p38 MAPK/NOX4 signaling pathway, which is crucial to the regulation of oxidative stress responses in cellular systems. By elucidating these mechanisms, the study seeks to confirm the potential of QCT not only as a protective agent against oxidative stress but also as a therapeutic agent that could be integrated in treatments of conditions characterized by heightened oxidative stress in endometrial cells.
UNASSIGNED: I n vitro cultures of HESCs were treated with QCT at different concentrations (0, 10, 20, and 40 μmol/L) for 24 h to verify the non-toxic effects of QCT on normal endometrial cells. Subsequently, 250 μmol/L H2O2 was used to incubate the cells for 12 h to establish an H2O2-induced HESCs injury model. HESCs were pretreated with QCT for 24 h, which was followed by stimulation with H2O2. Then, CCK-8 assay was performed to examine the cell viability and to screen for the effective intervention concentration. HESCs were divided into 3 groups, the control group, the H2O2 model group, and the H2O2+QCT group. Intracellular levels of reactive oxygen species (ROS) were precisely quantified using the DCFH-DA fluorescence assay, a method known for its accuracy in detecting and quantifying oxidative changes within the cell. The mitochondrial membrane potential was determined by JC-1 staining. Annexin Ⅴ/PI double staining and flow cytometry were performed to determine the effect of QCT on H2O2-induced apoptosis of HESCs. Furthermore, to delve deeper into the cellular mechanisms underlying the observed effects, Western blot analysis was conducted to measure the expression levels of the critical proteins involved in oxidative stress response, including NADPH oxidase 4 (NOX4), p38 mitogen-activated protein kinase (p38 MAPK), and phosphorylated p38 MAPK (p-p38 MAPK). This analysis helps increase understanding of the specific intracellular signaling pathways affected by QCT treatment, giving special attention to its potential for modulation of the p38 MAPK/NOX4 pathway, which plays a significant role in cellular defense mechanisms against oxidative stress.
UNASSIGNED: In this study, we started off by assessing the toxicity of QCT on normal endometrial cells. Our findings revealed that QCT at various concentrations (0, 10, 20, and 40 μmol/L) did not exhibit any cytotoxic effects, which laid the foundation for further investigation into its protective roles. In the H2O2-induced HESCs injury model, a significant reduction in cell viability was observed, which was linked to the generation of ROS and the resultant oxidative damage. However, pretreatment with QCT (10 μmol/L and 20 μmol/L) significantly enhanced cell viability after 24 h (P<0.05), with the 20 μmol/L concentration showing the most substantial effect. This suggests that QCT can effectively reverse the cellular damage caused by H2O2. Furthermore, the apoptosis assays demonstrated a significant increase in the apoptosis rates in the H2O2 model group compared to those in the control group (P<0.01). However, co-treatment with QCT significantly reversed this trend (P<0.05), indicating QCT\'s potential protective role in mitigating cell apoptosis. ROS assays showed that, compared to that in the control group, the average fluorescence intensity of ROS in the H2O2 model group significantly increased (P<0.01). QCT treatment significantly reduced the ROS fluorescence intensity in the H2O2+QCT group compared to the that in the H2O2 model group, suggesting an effective alleviation of oxidative damage (P<0.05). JC-1 staining for mitochondrial membrane potential changes revealed that compared to that in the control, the proportion of cells with decreased mitochondrial membrane potential significantly increased in the H2O2 model group (P<0.01). However, this proportion was significantly reduced in the QCT-treated group compared to that of the H2O2 model group (P<0.05). Finally, Western blot analysis indicated that the expression levels of NOX4 and p-p38 MAPK proteins were elevated in the H2O2 model group compared to those of the control group (P<0.05). Following QCT treatment, these protein levels significantly decreased compared to those of the H2O2 model group (P<0.05). These results suggest that QCT may exert its protective effects against oxidative stress by modulating the p38 MAPK/NOX4 signaling pathway.
UNASSIGNED: QCT has demonstrated significant protective effects against H2O2-induced oxidative damage in HESCs. This protection is primarily achieved through the effective reduction of ROS accumulation and the inhibition of critical signaling pathways involved in the oxidative stress response, notably the p38 MAPK/NOX4 pathway. The results of this study reveal that QCT\'s ability to modulate these pathways plays a key role in alleviating cellular damage associated with oxidative stress conditions. This indicates not only its potential as a protective agent against cellular oxidative stress, but also highlights its potential for therapeutic applications in treating conditions characterized by increased oxidative stress in the endometrium, thereby offering the prospect of enhancing reproductive health. Future studies should explore the long-term effects of QCT and its clinical efficacy in vivo, thereby providing a clear path toward its integration into therapeutic protocols.

UNASSIGNED: To investigate the effect of Sanshentongmai (SSTM) mixture on the regulation of oxidative damage to rat cardiomyocytes (H9C2) through microRNA-146a and its mechanism.
UNASSIGNED: H9C2 were cultured in vitro, H2O2 was used as an oxidant to create an oxidative damage model in H9C2 cells. SSTM intervention was administered to the H9C2 cells. Then, the changes in H2O2-induced oxidative damage in H9C2 cells and the expression of microRNA-146a were observed to explore the protective effect of SSTM on H9C2 and its mechanism. H9C2 cells cultured i n vitro were divided into 3 groups, including a control group, a model group of H2O2-induced oxidative damage (referred to hereafter as the model group), and a group given H2O2 modeling plus SSTM intervention at 500 μg/L for 72 h (referred to hereafter as the treatment group). The cell viability was measured by CCK8 assay. In addition, the levels of N-terminal pro-brain natriuretic peptide (Nt-proBNP), nitric oxide (NO), high-sensitivity C-reactive protein (Hs-CRP), and angiotensin were determined by enzyme-linked immunosorbent assay (ELISA). The expression level of microRNA-146a was determined by real-time PCR (RT-PCR).
UNASSIGNED: H9C2 cells were pretreated with SSTM at mass concentrations ranging from 200 to 1500 μg/L. Then, CCK8 assay was performed to measure cell viability and the findings showed that the improvement in cell proliferation reached its peak when the mass concentration of SSTM was 500 μg/L, which was subsequently used as the intervention concentration. ELISA was performed to measure the indicators related to heart failure, including Nt-proBNP, NO, Hs-CRP, and angiotensin Ⅱ. Compared with those of the control group, the expressions of Nt-proBNP and angiotensin Ⅱ in the treatment group were up-regulated (P<0.05), while the expression of NO was down-regulated (P<0.05). There was no significant difference in the expression of Hs-CRP between the treatment group and the control group. These findings indicate that SSTM could effectively ameliorate oxidative damage in H9C2 rat cardiomyocytes. Finally, according to the RT-PCR findings for the expression of microRNA-146a in each group, H2O2 treatment at 15 μmol/L could significantly reduce the expression of microRNA-146a, and the expression of microRNA-146a in the treatment group was nearly doubled compared with that in the model group. There was no significant difference between the treatment group and the control group.
UNASSIGNED: SSTM can significantly resist the H2O2-induced oxidative damage of H9C2 cells and may play a myocardial protective role by upregulating microRNA-146a.

Oral medication for ulcerative colitis (UC) is often hindered by challenges such as inadequate accumulation, limited penetration of mucus barriers, and the intricate task of mitigating excessive ROS and inflammatory cytokines. Here, we present a strategy involving sodium alginate microspheres (SAMs) incorporating M2 macrophage membrane (M2M)-coated Janus nanomotors (denominated as Motor@M2M) for targeted treatment of UC. SAM provides a protective barrier, ensuring that Motor@M2M withstands the harsh gastric milieu and exhibits controlled release. M2M enhances the targeting precision of nanomotors to inflammatory tissues and acts as a decoy for the neutralization of inflammatory cytokines. Catalytic decomposition of H2O2 by MnO2 in the oxidative microenvironment generates O2 bubbles, propelling Motor@M2M across the mucus barrier into inflamed colon tissues. Upon oral administration, Motor@M2M@SAM notably ameliorated UC severity, including inflammation mitigation, ROS scavenging, macrophage reprogramming, and restoration of the intestinal barrier and microbiota. Consequently, our investigation introduces a promising oral microsphere formulation of macrophage-biomimetic nanorobots, providing a promising approach for UC treatment.

UNASSIGNED: Reactive oxygen species (ROS) produced under oxidative stress is important for osteoclastogenesis. As a major member of the metallothionein (MT) family, metallothionein2 (MT2) can scavenge ROS in osteoblasts. However, the role of MT2 in osteoclastogenesis and ROS production in osteoclast precursors (OCPs) is unknown.
UNASSIGNED: In this study, we first investigated MT2 expression level in osteoporotic model mice. Next, we explored the roles of MT2 in osteoclastic differentiation and ROS production in OCPs. Ultimately, via rescue assays based on hydrogen peroxide (H2O2), the significance of ROS in MT-2-regulated osteoclastic differentiation was further elucidated.
UNASSIGNED: Compared with sham operated (Sham) mice, ovariectomized (OVX) mice displayed bone marrow primary OCPs (Ly6C+CD11b-) having higher ROS levels and lower MT2 expression. MT2 overexpression inhibited the formation of mature osteoclasts, while MT2 knockdown was contrary. Moreover, MT2 overexpression inhibited ROS production in OCPs, while MT2 knockdown exhibited the opposite effects. Notably, the inhibitory effect of MT2 overexpression on osteoclastogenesis and ROS production was blocked by the addition of H2O2.
UNASSIGNED: MT2 inhibits osteoclastogenesis through repressing ROS production in OCPs, which indicates that the strategy of upregulating MT2 in OCPs may be applied to the clinical treatment of osteoclastic bone loss.

Electrochemiluminescence (ECL) of luminol is a luminescence process that proceeds in the presence of reactive oxygen species (e.g. hydrogen peroxide (H2O2)) at a suitable electrode potential, the reaction mechanism of which is complicated and remains ambiguous. In this work, we report a visualization approach for measuring the thickness of the ECL layer (TEL) of the luminol/H2O2 system to decipher the reaction process by combined use of the microtube electrode, ECL microscopy, and finite element simulations. With the increase of solution pH, the ECL image captured with the microtube electrode tends to vary from spot to ring, corresponding to the decrease of TEL from >9.1 μm to ca. 4.3 μm. We propose that different intermediates are involved in the course of ECL reaction. At a low pH (e.g. pH < 9), a relatively large TEL is most likely determined by the diffusion of oxidized and deprotonated luminol intermediate that is neutral and has a long lifetime. While at a high pH (e.g. pH in the range of 10 to 12), the ECL reaction is controlled by short-lived radical intermediates of both luminol and superoxide anion. The proposed mechanism is proved theoretically by finite element simulations and experimentally by the apparent effect of concentration ratio of luminol/H2O2.

Water is a major requirement for our bodies, and alkaline water has induced an antioxidant response in a model of natural aging. A series of recent reports have shown that aging is related to reduced water intake. Hydrogen-rich water has been suggested to exert a general antioxidant effect in relation to both improving lifestyle and preventing a series of diseases. Here, we wanted to investigate the effect of the daily intake of hydrogen-rich alkaline water (HAW) in counteracting the redox imbalance induced in a model of H2O2-treated mice. Mice were treated with H2O2 for two weeks and either left untreated or supplied with HAW. The results show that HAW induced a reduction in the ROS plasmatic levels that was consistent with the increase in the circulating glutathione. At the same time, the reduction in plasmatic 8-hydroxy-2\'-deoxyguanosine was associated with reduced DNA damage in the whole body. Further analysis of the spleen and bone marrow cells showed a reduced ROS content consistent with a significantly reduced mitochondrial membrane potential and superoxide accumulation and an increase in spontaneous proliferation. This study provides evidence for a clear preventive and curative effect of HAW in a condition of systemic toxic condition and redox imbalance.

The photodegradation of azithromycin present was carried out in water using H2O2 under UV irradiation. The reaction variables considered in this study were the amount of H2O2 solution and the initial concentration of azithromycin to evaluate the performance of the photodegradation process. The azithromycin degradation was not observed in the dark during stirring for 20 min. The study showed an efficient photodegradation of azithromycin using H2O2 as an oxidant in the presence of UV irradiation. The azithromycin degradation was altered significantly by the pH of the irradiated solution. The degradation was low at an acidic pH and showed an increasing trend as the pH changed to basic. The azithromycin degradation increased with a higher amount (higher concentration) of H2O2. The degradation of azithromycin decreased with a higher concentration of azithromycin in the reacting solution. The highest degradation of AZT was achieved in 1 h using a 1.0 ppm AZT solution containing 3 mL of H2O2. The experimental data obtained were well-fitted to zero-order reaction kinetics. The results of this study were found quite excellent. They showed 100% degradation in 1 h when compared with those reported in the literature, both with photocatalysis using nanomaterials and photolysis using light irradiation and/or H2O2. The UV/H2O2 system was found to be quite efficient for the photodegradation of azithromycin, and this system can be applied to degrade other organic pollutants present in industrial wastewater.