Lower Reactive Oxygen Species Research Articles

Differentiation, Metabolism, and Cardioprotective Secretory Functions of Human Cardiac Stromal Cells from Ischemic and Endocarditis Patients.

This study investigates the characteristics of cardiac mesenchymal stem cell-like cells (CMSCLCs) isolated from the right atrial appendage of human donors with ischemia and a young patient with endocarditis (NE-CMSCLCs). Typical CMSCLCs from ischemic heart patients were derived from coronary artery bypass grafting procedures and compared against bone marrow mesenchymal stromal cells (BM-MSCs). NE-CMSCLCs had a normal immunophenotype, but exhibited enhanced osteogenic differentiation potential, rapid proliferation, reduced senescence, reduced glycolysis, and lower reactive oxygen species generation after oxidative stress compared with typical ischemic CMSCLCs. These differences suggest a unique functional status of NE-CMSCLCs, influenced by the donor health condition. Despite large variances in their paracrine secretome, NE-CMSCLCs retained therapeutic potential, as indicated by their ability to protect hypoxia/reoxygenation-injured human cardiomyocytes, albeit less effectively than typical CMSCLCs. This research describes a unique cell phenotype and underscores the importance of donor health status in the therapeutic efficacy of autologous cardiac cell therapy.

Programmable Release of Chemotherapeutics from Ferrocene-Based Injectable Hydrogels Slows Melanoma Growth.

Hydrogel-based injectable drug delivery systems provide temporally and spatially controlled drug release with reduced adverse effects on healthy tissues. Therefore, they represent a promising therapeutic option for unresectable solid tumor entities. In this study, a peptide-starPEG/hyaluronic acid-based physical hydrogel is modified with ferrocene to provide a programmable drug release orchestrated by matrix-drug interaction and local reactive oxygen species (ROS). The injectable ROS-responsive hydrogel (hiROSponse) exhibits adequate biocompatibility and biodegradability, which are important for clinical applications. HiROSponse is loaded with the two cytostatic drugs (hiROSponsedox/ptx) doxorubicin (dox) and paclitaxel (ptx). Dox is a hydrophilic compound and its release is mainly controlled by Fickian diffusion, while the hydrophobic interactions between ptx and ferrocene can control its release and thus be regulated by the oxidation of ferrocene to the more hydrophilic state of ferrocenium. In a syngeneic malignant melanoma-bearing mouse model, hiROSponsedox/ptx slows tumor growth without causing adverse side effects and doubles the relative survival probability. Programmable release is further demonstrated in a tumor model with a low physiological ROS level, where dox release, low dose local irradiation, and the resulting ROS-triggered ptx release lead to tumor growth inhibition and increased survival.

P-025 Mitochondrial activity in sperm is associated to blastocyst development: a double-donation study

Abstract Study question Do oxidative parameters in sperm affect oocyte fertilization or blastocyst development in double-donation ICSI cycles? Summary answer While intracellular oxidative stress in sperm does not suppose an impact on fertilization or embryo development, mitochondrial activity is related to increased blastocyst development rates What is known already Reactive oxygen species(ROS) are molecules causing a detrimental effect on sperm quality and function, especially when they are imbalanced with respect to the sperm and seminal plasma antioxidant capacity. Previous research have extensively demonstrated that sperm affected by oxidative stress(OS) show reduced fertilizing capacity, and lead to embryos with impaired development after conventional IVF. The role of OS in sperm in the case of ICSI is, however, controversial because many factors may cause a bias. Not only could this explain the inconsistent results reported thus far, but would also support the need of testing healthy donor gametes to reduce variability. Study design, size, duration This research was devised in the context of a collaboration between a sperm bank and a public university, and was set as a blinded, retrospective study that included samples from 45 sperm donors used in a total of 55 oocyte donation cycles. Intracellular levels of total ROS and of superoxides (O2•-), oxidative stress and mitochondrial activity (MA) were evaluated in frozen-thawed sperm donor samples, and related to the embryo outcomes obtained from the same samples. Participants/materials, setting, methods Samples from selected sperm donors were used to fertilize oocytes through ICSI in oocyte donation programs, and fertilization and blastocyst rates were recorded. Sperm viability and intracellular levels of total ROS and superoxides were determined through a combined assay (2’,7’-Dichlorofluorescin diacetate/Hydroethidine/Sytox Red); oxidative stress and sperm viability were assessed through co-staining with CellRox Far Red and propidium iodide (PI); and MA (mitochondrial membrane potential) and sperm viability were evaluated after staining with DiOC6(3) and PI. Main results and the role of chance The average and standard deviation for fertilization and blastocyst rates were 76.8%±17.3% and 67.5%±22.8%, respectively. Taking the viable sperm population into account, percentages of sperm with high ROS and low O2•- were 17.6%±15.9%, those with high ROS and high O2•- were 0.5%±0.4%, percentages of sperm with low ROS and low O2•- were 25.9%±9.2%, and those with low ROS and high O2•- were 54.5%±21.1%. The evaluation of oxidative stress with CellRox revealed that the percentage of viable sperm with high OS was 63.1%±16.5%. Neither intracellular levels of ROS and superoxides, nor oxidative stress in viable sperm were found to be correlated to fertilization or blastocyst rates (P>0.05). In spite of this, the percentage of viable sperm with high MA, which was 20.7%±10.5%, was observed to be positively correlated to blastocyst rates (Rs=0.276; P=0.04). While sperm mitochondria do not participate in further embryo development, a greater mitochondrial activity in post-thawed donor sperm could indicate a healthier sperm function. Mitochondrial activity could, therefore, be used as a predictive biomarker for embryo development. Limitations, reasons for caution The sample size is the main limitation of this study, despite the efforts made to include a high number of sperm donors. Wider implications of the findings Results obtained in the present study show that ICSI evades the detrimental effects of sperm oxidative stress on fertilization and embryo development. Yet, sperm mitochondrial activity could be used as a biomarker to test the ability of a sperm donor to generate healthy embryos that develop up to blastocyst stage. Trial registration number Not applicable

BcWRKY1 confers Botrytis cinerea susceptibility via inhibiting JA biosynthesis.

WRKYs play important roles in plant stress resistance. However, the role of WRKYs in non-heading Chinese cabbage (Brassica campestris ssp. chinensis) against Botrytis cinerea (B. cinerea) remains poorly understood. Herein, the expression of BcWRKY1 was induced by B. cinerea. Further, the role of BcWRKY1 in B. cinerea infection was identified. Silencing of BcWRKY1 in non-heading Chinese cabbage enhanced plant resistance to B. cinerea. After B. cinerea inoculation, BcWRKY1-silencing plants exhibited lower reactive oxygen species (ROS) content, higher jasmonic acid (JA) content, and the expression level of JA biosynthesis genes, BcOPR3, BcLOX3-1 and BcLOX3-2 were upregulated. Overexpression of BcWRKY1 in Arabidopsis exhibited a complementary phenotype. By directly targeting W-boxes in the promoter of BcLOX3-2, BcWRKY1 inhibited the transcription of this gene. In addition, 13 candidate interacting proteins of BcWRKY1 were identified by yeast two-hybrid (Y2H) screening, and the interaction between BcWRKY1 and BcCaM6 weakened the inhibition of BcLOX3-2. In summary, our findings suggest that BcWRKY1 interacts with BcCaM6 to negatively regulate disease resistance.

Understanding the Role of Low-Dose Polystyrene Microplastic in Copper Toxicity to Rice Seed (Oryza sativa L.).

There is still much to learn with respect to the potential for microplastics (MPs) to interact with environmental toxins and biota. In the present study, we investigated the effect of MPs on the toxicity of copper (Cu) to rice seeds (Oryza sativa L.). The 7-day median effective concentration (EC50) value of MPs on rice seed germination was 864 mg/L (95% confidence interval [CI] 839 to 897 mg/L). We found that MPs slightly reduced Cu toxicity to rice seeds. The 7-day EC50 of Cu on rice seed germination increased from 7.29 mg/L (95% CI 7.10-7.52 mg/L) to 7.93 mg/L (95% CI 7.58-8.08 mg/L) in the presence of 20 mg/L MPs. We examined this toxicity reduction phenomenon by investigating the role of MPs in the process of Cu transport, Cu accumulation, and metabolic responses. Further investigation found that the MPs used in the present study hardly adsorbed Cu, but these MPs accumulated on the coats of rice seeds and significantly reduced Cu accumulation in rice seedlings. When Cu concentration was 10 mg/L, the presence of MPs reduced the accumulation of Cu in rice seedlings by 34%. We also found that, compared with only Cu present, the addition of MPs resulted in lower reactive oxygen species accumulation and higher catalase activity and glutathione levels in rice seedlings, which also contributed to Cu toxicity reduction. Collectively, the present study shows that polystyrene MPs have the potential to form associations with plant structures which can ultimately impact heavy metal bioaccessibility and therefore toxicity. Environ Toxicol Chem 2024;00:1-10. © 2024 SETAC.

Simultaneous Protonation and Metalation of a Porphyrin Covalent Organic Framework Enhance Photodynamic Therapy.

Covalent organic frameworks (COFs) have been explored for photodynamic therapy (PDT) of cancer, but their antitumor efficacy is limited by excited state quenching and low reactive oxygen species generation efficiency. Herein, we report a simultaneous protonation and metalation strategy to significantly enhance the PDT efficacy of a nanoscale two-dimensional imine-linked porphyrin-COF. The neutral and unmetalated porphyrin-COF (Ptp) and the protonated and metalated porphyrin-COF (Ptp-Fe) were synthesized via imine condensation between 5,10,15,20-tetrakis(4-aminophenyl)porphyrin and terephthalaldehyde in the absence and presence of ferric chloride, respectively. The presence of ferric chloride generated both doubly protonated and Fe3+-coordinated porphyrin units, which red-shifted and increased the Q-band absorption and disrupted exciton migration to prevent excited state quenching, respectively. Under light irradiation, rapid energy transfer from protonated porphyrins to Fe3+-coordinated porphyrins in Ptp-Fe enabled 1O2 and hydroxyl radical generation via type II and type I PDT processes. Ptp-Fe also catalyzed the conversion of hydrogen peroxide to hydroxy radical through a photoenhanced Fenton-like reaction under slightly acidic conditions and light illumination. As a result, Ptp-Fe-mediated PDT exhibited much higher cytotoxicity than Ptp-mediated PDT on CT26 and 4T1 cancer cells. Ptp-Fe-mediated PDT afforded potent antitumor efficacy in subcutaneous CT26 murine colon cancer and orthotopic 4T1 murine triple-negative breast tumors and prevented metastasis of 4T1 breast cancer to the lungs. This work underscores the role of fine-tuning the molecular structures of COFs in significantly enhancing their PDT efficacy.

Lipoic Acid Can Maintain Stimulation of the Antioxidant System at Lower Reactive Oxygen Species, Ascorbate and Glutathione Levels in Osmotic Stressed Maize

Lipoic Acid Can Maintain Stimulation of the Antioxidant System at Lower Reactive Oxygen Species, Ascorbate and Glutathione Levels in Osmotic Stressed Maize

“Butterfly-effect” nano-platforms for cascade immune amplification and tumor clearance through multi-modal therapy and immune sensitization

Combined dynamic tumor therapy of photodynamic therapy (PDT), sonodynamic therapy (SDT) and microwave dynamic therapy (MDT) can overcome the limitations of single reactive oxygen species (ROS)-based therapy (including limited tissue penetration depth and low ROS production). However, changes in the tumor microenvironment caused by ROS amplification and oxygen depletion induce severe immunosuppression at the tumor site, indicating effective immunosensitization of the tumors are urgently needed. Here, melanin-hematoporphyrin-chloroquine R837-hyaluronic acid (MHRH) nanoplatform that can simultaneously respond to 980 nm laser /1064 nm laser/ultrasonic/microwave was prepared for PDT/SDT/MDT, achieving outbreak of ROS in deep tumor. More importantly, the photothermal ablation and the participation of chloroquine R837 of MHRH NPs reversed the immunosuppression caused by oxygen depletion after ROS outbreak by promoting DCs maturation and secretion of macrophage exosomes. In summary, the natural MHRH nano-platform supplies an obvious anti-tumor “butterfly effect” through ROS outbreak, thermal ablation and significant immunosuppressive reversal, which provides a new and promising combined strategy of ROS-dynamic therapy and immune agonists in deep tumor tissues.

Proteomics of tumor and serum samples from isocitrate dehydrogenase-wildtype glioblastoma patients: is the detoxification of reactive oxygen species associated with shorter survival?

Proteomics has been little used for the identification of novel prognostic and/or therapeutic markers in isocitrate dehydrogenase (IDH)-wildtype glioblastoma (GB). In this study, we analyzed 50 tumor and 30 serum samples from short- and long-term survivors of IDH-wildtype GB (STS and LTS, respectively) by data-independent acquisition mass spectrometry (DIA-MS)-based proteomics, with the aim of identifying such markers. DIA-MS identified 5422 and 826 normalized proteins in tumor and serum samples, respectively, with only three tumor proteins and 26 serum proteins displaying significant differential expression between the STS and LTS groups. These dysregulated proteins were principally associated with the detoxification of reactive oxygen species (ROS). In particular, GB patients in the STS group had high serum levels of malate dehydrogenase 1 (MDH1) and ribonuclease inhibitor 1 (RNH1) and low tumor levels of fatty acid-binding protein 7 (FABP7), which may have enabled them to maintain low ROS levels, counteracting the effects of the first-line treatment with radiotherapy plus concomitant and adjuvant temozolomide. A blood score built on the levels of MDH1 and RNH1 expression was found to be an independent prognostic factor for survival based on the serum proteome data for a cohort of 96 IDH-wildtype GB patients. This study highlights the utility of circulating MDH1 and RNH1 biomarkers for determining the prognosis of patients with IDH-wildtype GB. Furthermore, the pathways driven by these biomarkers, and the tumor FABP7 pathway, may constitute promising therapeutic targets for blocking ROS detoxification to overcome resistance to chemoradiotherapy in potential GB STS.

HMGA2 promotes resistance against paclitaxel by targeting the p53 signaling pathway in colorectal cancer cells

Colorectal cancer is one of the most common malignancies and ranks second in terms of cancer-related mortality worldwide due to its metastasis, drug resistance, and reoccurrence. High-mobility gene group A2 (HMGA2) is overexpressed in colorectal cancer, contributing to the aggressiveness of tumor malignance, and promotes drug resistance in many types of cancer. However, the underlying molecular mechanism of HMGA2 is yet to be elucidated. In this study, we showed that HMGA2 is overexpressed in colorectal cancer tissue, and knockdown of HMGA2 significantly inhibited colorectal cancer cell growth and migratory capability. HMGA2 regulates the cancer cell response to a widely used anti-cancer drug, paclitaxel (PTX). HMGA2 knockdown increased cell death, whereas HMGA2 overexpression decreased cell death after PTX treatment. Furthermore, lower reactive oxygen species (ROS) levels and mitochondrial potential were detected in HMGA2 overexpression cells after PTX treatment. However, HMGA2 knockdown produced the opposite effect. RNA sequencing showed a p53 signaling pathway-dependent regulation in HMGA2 knockdown cells. Combined with p53 inhibitors and HMGA2 knockdown, a synergetic effect of more cell death was observed in colorectal cancer cells after PTX treatment. Thus, we showed that HMGA2 can activate p53 signaling to regulate colorectal cancer cell death after PTX treatment. Altogether, our results reveal novel insights into the molecular mechanisms underlying HMGA2-mediated cancer cell resistance against PTX and highlight the potential of targeting HMGA2 and p53 signaling for the therapeutic investigation of colorectal cancer.

Expanded ROS Generation and Hypoxia Reversal: Excipient-free Self-assembled Nanotheranostics for Enhanced Cancer Photodynamic Immunotherapy.

The efficacy of photodynamic therapy (PDT)-related cancer therapies is significantly restricted by two irreconcilable obstacles, i.e., low reactive oxygen species (ROS) generation capability and hypoxia which constrains the immune response. Herein, this work develops a self-assembled clinical photosensitizer indocyanine green (ICG) and the HSP90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) nanoparticles (ISDN) without any excipient. This work discovers that the hydrophobic interaction forces between ICG and 17-DMAG promote the photostability of ICG and its intersystem crossing (ISC) process, thereby improving the ROS quantum yield from 0.112 to 0.46. Augmented ROS generation enhances PDT efficacy and further enhances immunogenic cell death (ICD) effects. 17-DMAG inhibits the HSP90/hypoxia-inducible factor 1α (HIF-1α) axis to dramatically reverse the immunosuppressive tumor microenvironment caused by PDT-aggravated hypoxia. In a mouse model of pancreatic cancer, ISDN markedly improve cytotoxic T lymphocyte infiltration and MHC I and MHC II activation, demonstrating the superior ICD effects in situ tumor and the powerful systematic antitumor immunity generation, eventually achieving vigorous antitumor and recurrence resistance. This study proposes an unsophisticated and versatile strategy to significantly improve PDT efficacy for enhancing systemic antitumor immunity and potentially extending it to multiple cancers.

Enhanced Anti-Inflammatory Activity of Tilianin Based on the Novel Amorphous Nanocrystals

Tilianin (Til), a flavonoid glycoside, is well-known for its therapeutic promise in treating inflammatory disorders. Its poor water solubility and permeability limit its clinical applicability. In order to overcome these restrictions, an antisolvent precipitation and ultrasonication technique was used to prepare amorphous tilianin nanocrystals (Til NCs). We have adjusted the organic solvents, oil-to-water ratio, stabilizer composition, and ultrasonic power and time by combining single-factor and central composite design (CCD) methodologies. The features of Til NCs were characterized using powder X-ray diffraction (PXRD), scanning calorimetry (DSC), and transmission electron microscopy (TEM). Specifically, the optimized Til NCs were needle-like with a particle size ranging from 90 to 130 nm. PVA (0.3%, w/v) and TPGS (0.08%, w/v) stabilized them well. For at least two months, these Til NCs stayed amorphous and showed an impressive stability at 4 °C and 25 °C. Remarkably, Til NCs dissolved almost 20 times faster in simulated intestinal fluid (SIF) than they did in crude Til. In RAW264.7 cells, Til NCs also showed a better cellular absorption as well as safety and protective qualities. Til NCs were shown to drastically lower reactive oxygen species (ROS), TNF-α, IL-1β, and IL-6 in anti-inflammatory experiments, while increasing IL-10 levels and encouraging M1 macrophages to adopt the anti-inflammatory M2 phenotype. Our results highlight the potential of amorphous Til NCs as a viable approach to improve Til’s anti-inflammatory effectiveness, solubility, and dissolving rate.

Cascade loop of ferroptosis induction and immunotherapy based on metal‐phenolic networks for combined therapy of colorectal cancer

AbstractCancer immunotherapy is the most promising method for tumor therapy, while ferroptosis could activate the immunogenicity of cancer and strengthen the cellular immune response. However, limited by the complex tumor microenvironment, the abundant glutathione (GSH) and low reactive oxygen species (ROS) seriously weaken ferroptosis and the immune response. Herein, the authors report photothermal metal‐phenolic networks (MPNs) supplied with buthionine sulfoximine (BSO) by reducing levels of GSH and then trapping the tumor cells in the ferroptosis and immunotherapy cascade loop to eliminate colorectal cancer (CRC). The MPNs coated with the model antigen ovalbumin can accumulate at the tumor site, mediate immunogenic cell death (ICD) under NIR irradiation, and initiate tumoricidal immunity. Then the activated CD8+ T cells would release IFN‐γ to inhibit GPX4 and promote the immunogenic ferroptosis induced by Fe3+ and BSO. Finally, the tumor cells at intertumoral and intratumoral levels would be involved in the ferroptosis‐dominated cancer‐immunity circle for CRC eradication, resulting in outstanding therapeutic outcomes in both primary and distant tumor models. Overall, this strategy employs a photothermal nanoplatform to rapidly stimulate ICD and restrain the oxidation defense system, which provides a promising approach to significantly amplify the “cascade loop” of ferroptosis induction and immunotherapy for treatment of CRC.

Effects of dietary supplementation with macroalgae on sperm quality and antioxidant system in Senegalese sole

Within the efforts in the search for novel feed ingredients in aquaculture, macroalgae are being widely explored due to their diversity of bioactive compounds with considerable prophylactic and therapeutic potential. Plocamium cartilagineum and Sargassum vulgare, have the potential to positively impact fish health, mainly due to their antioxidant properties. The production of Senegalese sole (Solea senegalensis) still faces some constraints due to the low sperm quantity and quality of males from captivity, which is highly affected by oxidative stress. We hypothesized that the scavenger ability of P. cartilagineum and S. vulgare could ameliorate the reproductive performance of Senegalese sole males, once incorporated in the broodstock feeds. In this experiment, broodstock groups were fed with three different formulated experimental diets for 60 days: Control (Ctrl), a diet supplemented with 5% P. cartilagineum (Pc), and a diet supplemented with 5% S. vulgare (Sv). Fish were sampled twice to evaluate sperm quality using different techniques: sperm motility by Computer Assisted Sperm Analysis (CASA) software, and cell viability and Reactive Oxygen Species (ROS) by flow cytometer. At the final sampling, 6 fish per treatment were sacrificed and gonads were extracted to determine the relative expression of anti- and pro-apoptotic genes (bcl2b, bcl-x, mcl1b, badb, bax, boka), and genes involved in fish antioxidant system (sod3, cat, gpx, hsp70). Sex steroids were measured on blood plasma by ELISA. Specific growth rate (SGR) and feed efficiency were also evaluated at the end of the experiment. Senegalese sole breeders fed with Pc diet for 60 days showed enhanced sperm total motility and cell viability at the end of the experiment, when compared with the Ctrl diet. On the other hand, fish fed with Sv diet had lower spermatozoa intracellular ROS and upregulated gpx in the gonads. No differences were obtained in levels of sex steroids and gonadal apoptotic system after 60 days of feeding, however, the macroalgae species and the percentages of incorporation used proved to positively modulate different spermatozoa traits.

Panax quinquefolius saponins and panax notoginseng saponins attenuate myocardial hypoxia-reoxygenation injury by reducing excessive mitophagy.

Panax quinquefolius saponins (PQS) and Panax notoginseng saponins (PNS) are key bioactive compounds in Panax quinquefolius L. and Panax notoginseng, commonly used in the treatment of clinical ischemic heart disease. However, their potential in mitigating myocardial ischemia-reperfusion injury remains uncertain. This study aims to evaluate the protective effects of combined PQS and PNS administration in myocardial hypoxia/reoxygenation (H/R) injury and explore the underlying mechanisms. To investigate the involvement of HIF-1α/BNIP3 mitophagy pathway in the myocardial protection conferred by PNS and PQS, we employed small interfering BNIP3 (siBNIP3) to silence key proteins of the pathway. H9C2 cells were categorized into four groups: control, H/R, H/R + PQS + PNS, and H/R + PQS + PNS+siBNIP3. Cell viability was assessed by Cell Counting Kit-8, apoptosis rates determined via flow cytometry, mitochondrial membrane potential assessed with the JC-1 fluorescent probes, intracellular reactive oxygen species detected with 2',7'-dichlorodihydrofluorescein diacetate, mitochondrial superoxide production quantified with MitoSOX Red, and autophagic flux monitored with mRFP-GFP-LC3 adenoviral vectors. Autophagosomes and their ultrastructure were visualized through transmission electron microscopy. Moreover, mRNA and protein levels were analyzed via real-time PCR and Western blotting. PQS + PNS administration significantly increased cell viability, reduced apoptosis, lowered reactive oxygen species levels and mitochondrial superoxide production, mitigated mitochondrial dysfunction, and induced autophagic flux. Notably, siBNIP3 intervention did not counteract the cardioprotective effect of PQS + PNS. The PQS + PNS group showed downregulated mRNA expression of HIF-1α and BNIP3, along with reduced HIF-1α protein expression compared to the H/R group. PQS + PNS protects against myocardial H/R injury, potentially by downregulating mitophagy through the HIF-1α/BNIP3 pathway.

Nitrate-rich beetroot juice supplementation in midlife and older adults with renal dysfunction increases vascular endothelial function and changes the circulating milieu to improve endothelial cell nitric oxide production and oxidative stress

BACKGROUND: Midlife and older (ML/O) adults with mild-to-moderate renal dysfunction (MRD) are at increased risk for cardiovascular disease (CVD). A key antecedent to CVD in ML/O adults with MRD is vascular endothelial dysfunction, mediated by declines in nitric oxide (NO) bioavailability due to excess reactive oxygen species (ROS)-related oxidative stress. We have shown that targeting the nitrate-nitrite-NO pathway with sodium nitrite in heathy ML/O adults improves endothelial function and changes the circulating milieu to lower endothelial cell (EC) ROS bioactivity. However, if nitrate-rich beetroot juice (N-BRJ) is effective for improving endothelial function in ML/O men and women with MRD is unknown. HYPOTHESES: We tested the hypotheses that chronic N-BRJ in ML/O men and women with MRD would: 1) improve endothelial function and 2) induce changes to the circulating milieu to increase EC NO production and lower EC ROS bioactivity. We also assessed possible sex differences in the effcacy of N-BRJ for improving endothelial function. METHODS: Twenty-six ML/O men and women with MRD (estimated glomerular filtration rate [eGFR; CKD-EPI]: 40-89 mL/min/1.73m2) underwent three months of supplementation with N-BRJ (70 mL with 6.45 mmol nitrate/day) (n=13, 7 women; age: 65±2 years; eGFR: 69.2±3.3 mL/min/1.73m2) or nitrate-depleted BRJ (placebo, PBO) (n=13, 7 women; age: 68±2 years; eGFR: 79.8±3.1 mL/min/1.73m2) in a randomized, placebo-controlled, parallel-group design clinical trial. Endothelial function was assessed by brachial artery flow-mediated dilation (FMDBA). Smooth muscle sensitivity to NO was assessed by brachial artery dilation to sublingual nitroglycerin. Human aortic ECs (HAECs) in culture were exposed to 10% subject serum (n=10[6-7 women]/group) collected before and after N-BRJ and PBO supplementation. Acetylcholine-stimulated NO production (DAR-4M-AM) and whole-cell ROS bioactivity (CellROX) were assessed in HAECs using immunofluorescence. Results: N-BRJ supplementation increased FMDBA by 28% (pre: 4.6±0.7%, post: 5.9±0.8%; p=0.03). FMDBA did not change with PBO (pre: 4.6±0.9%, post: 4.7±0.8%; p>0.05). Traditional CVD risk factors (i.e., blood pressure, cholesterol) and smooth muscle sensitivity to NO were unchanged in both groups (p>0.05). Preliminary assessments suggest greater improvements in endothelial function with N-BRJ in women (Δ=post-pre intervention; ΔFMDBA=1.6±0.4) compared to men (ΔFMDBA=0.9±1.0). Compared to pre-intervention, NO production was (trending) 7% higher (p=0.05) and ROS bioactivity was 25% lower (p=0.02) in HAECs exposed to serum collected post N-BRJ. Serum from PBO had no effects (p>0.05). CONCLUSION: N-BRJ supplementation in ML/O adults with MRD holds promise for improving endothelial function, in part by inducing changes to the circulating milieu that increase NO production and decrease oxidative stress in ECs. The effects on endothelial function may be greater in women compared to men. Targeting the nitrate-nitrite-NO pathway with N-BRJ may be an effective strategy for improving endothelial function in ML/O adults with renal dysfunction to possibly reduce CVD risk. K01DK115524 (MJR); R01AG013038 (DRS); F32HL167552 (KOM); NIH/NCATS CTSA UL1TR002535. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

GPX4 transcriptionally promotes liver cancer metastasis via GRHL3/PTEN/PI3K/AKT axis

Hepatocellular carcinoma (HCC) is among the most fatal types of malignancy, with a high prevalence of relapse and limited treatment options. As a critical regulator of ferroptosis and redox homeostasis, glutathione peroxidase 4 (GPX4) is commonly upregulated in HCC and is hypothesized to facilitate cancer metastasis, but this has not been fully explored in HCC. Here, we report that up-regulated GPX4 expression in HCC is strongly associated with tumor metastasis. FACS-based in vivo and in vitro analysis revealed that a cell subpopulation featuring lower cellular reactive oxygen species levels and ferroptosis resistance were involved in GPX4-mediated HCC metastasis. Mechanistically, GPX4 overexpressed in HCC tumor cells was enriched in the nucleus and transcriptionally silenced GRHL3 expression, thereby activating PTEN/PI3K/AKT signaling and promoting HCC metastasis. Functional studies demonstrated that GPX4 amino acids 110–145 are a binding site that interacts with the GRHL3 promoter. As AKT is a downstream target of GPX4, we combined the AKT inhibitor, AKT-IN3, with lenvatinib to effectively inhibit HCC tumor cell metastasis. Overall, these results indicate that the GPX4/GRHL3/PTEN/PI3K/AKT axis controls HCC cell metastasis and lenvatinib combined with AKT-IN3 represents a potential therapeutic strategy for patients with metastatic HCC.

Melatonin seed priming improves early establishment and water stress tolerance of peanut

Water stress is a major cause of yield loss in peanut cultivation. Melatonin seed priming has been used to enhance stress tolerance in several crops, but not in peanut. We investigated the impact of seed priming with melatonin on the growth, development, and drought tolerance of two peanut cultivars, TUFRunner™ ‘511’, a drought tolerant cultivar, and New Mexico Valencia A, a drought sensitive cultivar. Peanut seed priming tests using variable rates of melatonin (0–200 μM), indicated that 50 μM of melatonin resulted in more uniform seed germination and improved seedling growth in both cultivars under non stress conditions. Seed priming with melatonin also promoted vegetative growth, as evidenced by higher whole-plant transpiration, net CO2 assimilation, and root water uptake under both well-watered and water stress conditions in both cultivars. Higher antioxidant activity and protective osmolyte accumulation, lower reactive oxygen species accumulation and membrane damage were observed in primed compared with non-primed plants. Seed priming with melatonin induced a growth promoting effect that was more evident under well-watered conditions for TUFRunnner™ ‘511’, whereas for New Mexico Valencia A, major differences in physiological responses were observed under water stress conditions. New Mexico Valencia A primed plants exhibited a more sensitized stress response, with faster down-regulation of photosynthesis and transpiration compared with non-primed plants. The results demonstrate that melatonin seed priming has significant potential to improve early establishment and promote growth of peanut under optimal conditions, while also improve stress tolerance during water stress.

Identification of a set of genes potentially responsible for resistance to ferroptosis in lung adenocarcinoma cancer stem cells

Scientific literature supports the evidence that cancer stem cells (CSCs) retain inside low reactive oxygen species (ROS) levels and are, therefore, less susceptible to cell death, including ferroptosis, a type of cell death dependent on iron-driven lipid peroxidation. A collection of lung adenocarcinoma (LUAD) primary cell lines derived from malignant pleural effusions (MPEs) of patients was used to obtain 3D spheroids enriched for stem‐like properties. We observed that the ferroptosis inducer RSL3 triggered lipid peroxidation and cell death in LUAD cells when grown in 2D conditions; however, when grown in 3D conditions, all cell lines underwent a phenotypic switch, exhibiting substantial resistance to RSL3 and, therefore, protection against ferroptotic cell death. Interestingly, this phenomenon was reversed by disrupting 3D cells and growing them back in adherence, supporting the idea of CSCs plasticity, which holds that cancer cells have the dynamic ability to transition between a CSC state and a non-CSC state. Molecular analyses showed that ferroptosis resistance in 3D spheroids correlated with an increased expression of antioxidant genes and high levels of proteins involved in iron storage and export, indicating protection against oxidative stress and low availability of iron for the initiation of ferroptosis. Moreover, transcriptomic analyses highlighted a novel subset of genes commonly modulated in 3D spheroids and potentially capable of driving ferroptosis protection in LUAD-CSCs, thus allowing to better understand the mechanisms of CSC-mediated drug resistance in tumors.

Synthetic modulation of ROS scavenging during host—Sclerotinia sclerotiorum interaction: a new strategy for the development of highly resistant plants

Sclerotinia sclerotiorum is a widespread fungal pathogen responsible for significant crop losses across the globe. The challenge of breeding resistant varieties is exacerbated by the fungus's sophisticated pathogenic mechanisms. A pivotal factor in the host-pathogen interaction is the regulation of reactive oxygen species (ROS) within both the fungi and the host plants. However, there is currently no efficient strategy to leverage this interaction mechanism for developing disease-resistant crop varieties. Here, we introduce an engineered ROS scavenging system designated as syn-ROS for impairing ROS neutralization in S. sclerotiorum while concurrently fortifying it in the host. The syn-ROS system comprises gene silencing constructs targeting the S. sclerotiorum Cu/Zn superoxide dismutase (SsSOD) and its copper chaperone (SsCCS), alongside overexpression constructs for the Arabidopsis thaliana AtSOD1 and AtCCS. Transgenic plants carrying the syn-ROS system demonstrated a marked enhancement in resistance to S. sclerotiorum. Upon infection, the expression of SsSOD and SsCCS was reduced, while the expression of AtSOD1 and AtCCS was enhanced in syn-ROS transgenic plants. Moreover, the infected syn-ROS plants showed decreased Cu/Zn SOD enzyme activity and elevated ROS concentrations within the fungal cells. In contrast, the cells of A. thaliana manifested increased Cu/Zn SOD enzyme activity and lowered ROS levels. Collectively, these findings suggest a novel and promising approach for contriving plants with robust resistance by synthetically manipulating ROS scavenging activities in the interaction between the host and S. sclerotiorum.