Elevated Levels Of Reactive Oxygen Species Research Articles

Copper-Based Composites Nanoparticles Improve Triple-Negative Breast Cancer Treatment with Induction of Apoptosis-Cuproptosis and Immune Activation.

The synergistic effect of apoptosis and cuproptosis, along with the activation of the immune system, presents a promising approach to enhance the efficacy against triple-negative breast cancer (TNBC). Here, two prodrugs are synthesized: a reactive oxygen species (ROS)-responsive prodrug PEG-TK-DOX and a glutathione (GSH)-responsive prodrug PEG-DTPA-SS-CPT. These prodrugs are self-assembled and chelated Cu2+ to prepare nanoparticle PCD@Cu that simultaneously loaded doxorubicin (DOX), camptothecin (CPT), and Cu2+. The elevated levels of ROS and GSH in TNBC cells disrupted the PCD@Cu structure, leading to the release of Cu+, DOX, and CPT and the depletion of GSH. DOX and CPT triggered apoptosis with immunogenic cell death (ICD) in TNBC cells. Simultaneously, PCD@Cu downregulated the expression of copper transporting ATPase 2 (ATP7B), causing a significant accumulation of copper ions in TNBC cells. This further induced the aggregation of lipoylated dihydrolipoamide S-acetyltransferase (DLAT) and downregulation of iron-sulfur (Fe-S) cluster proteins, ultimately leading to cuproptosis and ICD in TNBC. In vitro and in vivo experiments confirmed that PCD@Cu induced apoptosis and cuproptosis in TNBC and activated the immune system, demonstrating strong anti-tumor capabilities. Moreover, PCD@Cu exhibited an excellent biosafety profile. Overall, this study provides a promising strategy for effective TNBC therapy.

The Impact of Hydrogen Inhalation Therapy on Blood Reactive Oxygen Species Levels: A Randomized Controlled Study

Reactive Oxygen Species (ROS) play a key role in physiological processes. However, the imbalance between ROS and antioxidants in favor of the former causes oxidative stress linked to numerous pathologies. Due to its unique attributes, including distinguished permeability and selective antioxidant capability, molecular hydrogen (H2) has become an essential therapeutic agent. Hydrogen Inhalation Therapy (HIT) has come to light as a promising strategy to counteract oxidative stress. In this randomized controlled study, we aimed to evaluate the effectiveness of HIT in reducing blood ROS levels. 37 participants with elevated ROS levels (d-ROMs value > 350 U.CARR) were enrolled in the study. Participants were divided into test and control groups. The test group participants received HIT, and then their blood ROS levels were measured immediately post-treatment and after 24 hours. Their results were compared to those of the control group participants who did not undergo HIT. The test group demonstrated a significant reduction in blood ROS levels after the treatment. These findings suggested the efficacy of HIT in reducing oxidative stress.

P-041 Impact of cigarette smoking on level of sperm reactive oxygen species in normozoospermic men

Abstract Study question Does cigarette smoking influence the levels of sperm reactive oxygen species (ROS) in men with normal semen routine parameters? Summary answer Cigarettes impact the sperm ROS of normozoospermic smokers, whose sperm ROS level is elevated when they smoke equal to or more than 10 cigarettes daily. What is known already Increasing evidence indicates that oxidative stress (OS) plays an independent role in the etiology of male infertility, with 30% to 80% of infertile men having elevated ROS levels in semen. Cigarette smoking leads to an imbalance between ROS and antioxidants in the semen of smokers, which may negatively affect semen quality and male fertility. However, few studies concern whether cigarette smoking would influence the sperm ROS levels in normozoospermic men. Study design, size, duration Data of semen analysis from January 2021 to December 2023 were involved. Men with normal semen routine parameters, including sperm concentration, total sperm number, sperm progressive motility, total motility and normal forms of sperm morphology, were included in the study. Sperm ROS levels of normozoospermic men were retrospectively analyzed. Men with varicocele and leucocytospermia were excluded. Participants/materials, setting, methods Sperm count and motility were analyzed by the computer-assisted sperm analysis (CASA) system, while sperm morphology was examined after the Diff-Quik rapid staining procedure. Sperm ROS was measured by flow cytometry using the probe DCFH-DA. Sperm ROS levels of smokers and non-smokers were compared by the Mann-Whitney U test. The Kruskal-Wallis H test was used for the comparison of sperm ROS levels among the control group and smoking subgroups. Main results and the role of chance A total of 2946 subjects were involved in the present study. The included subjects were divided into smokers (n = 730) and non-smokers (n = 2216) according to the clinical records. And the included smokers were subsequently divided into three subgroups according to the daily cigarettes taken, which were group A (1∼9 cigarettes/day, n = 184), group B (1∼19 cigarettes/day, n = 315), and group C (>20 cigarettes/day, n = 231). No statistically significant differences in age or BMI were found between smokers and non-smokers with normozoospermia. The sperm ROS level of the smoker was higher than that of the non-smoker [14.53% (14.84%) vs. 13.07% (12.09%), p = 0.001]. Compared to the control group (non-smoker), the sperm ROS levels of group B [13.07% (12.09%) vs. 15.44% (14.28%), p = 0.002] and group C [13.07% (12.09%) vs. 14.80% (14.31%)., p = 0.042] were significantly elevated. ROS levels in the control group and group A were comparable [13.07% (12.09%) vs. 13.46% (15.74%)., p = 0.391]. Limitations, reasons for caution It is a single-center study and the above results were from a retrospective analysis. Wider implications of the findings The above results indicate that cigarette smoking, although it would not deteriorate semen routine parameters, may increase the ROS level in sperm. Elevated ROS in sperm may lead to an imbalance of redox in sperm, which may contribute to male infertility. Trial registration number not applicable

Stimuli-Responsive mRNA Vaccines to Induce Robust CD8+ T Cell Response via ROS-Mediated Innate Immunity Boosting.

The messenger RNA (mRNA) vaccines hold great significance in contagion prevention and cancer immunotherapy. However, safely and effectively harnessing innate immunity to stimulate robust and durable adaptive immune protection is crucial, yet challenging. In this study, we synthesized a library of stimuli-responsive bivalent ionizable lipids (srBiv iLPs) with smart molecular blocks responsive to esterase, H2O2, cytochrome P450, alkaline phosphatase, nitroreductase, or glutathione (GSH), aiming to leverage physiological cues to trigger fast lipid degradation, promote mRNA translation, and induce robust antitumor immunity via reactive oxygen species (ROS)-mediated boosting. After subcutaneous immunization, esterase-responsive vaccine (eBiv-mVac) was rapidly internalized and transported into the draining lymph nodes. It then underwent fast decaging and self-immolative degradation in esterase-rich antigen-presenting cells, releasing sufficient mRNA for antigen translation and massive reactive quinone methides to elevate ROS levels. This resulted in broad activation of innate immunity to boost T cell response, prompting a large number of primed antigen-specific CD8+ T cells to circulate and infiltrate into tumors (>1000-fold versus unvaccinated control), thereby orchestrating innate and adaptive immunity to control tumor growth. Moreover, by further combining our vaccination strategy with immune checkpoint blockade, we demonstrated a synergism that significantly amplified the magnitude and function of antigen-specific CD8+ T cells. This, in turn, caused potent systemic antitumor efficacy and prolonged survival with high complete response rate in xenograft and metastasis models. Overall, our generalized stimuli-responsive mRNA delivery platform promises a paradigm shift in the design of potent vaccines for cancer immunotherapy, as well as effective and precise carriers for gene editing, protein replacement, and cell engineering.

Role of oxidative stress in the concurrent development of osteoporosis and tendinopathy: Emerging challenges and prospects for treatment modalities.

Both osteoporosis and tendinopathy are widely prevalent disorders, encountered in diverse medical contexts. Whilst each condition has distinct pathophysiological characteristics, they share several risk factors and underlying causes. Notably, oxidative stress emerges as a crucial intersecting factor, playing a pivotal role in the onset and progression of both diseases. This imbalance arises from a dysregulation in generating and neutralising reactive oxygen species (ROS), leading to an abnormal oxidative environment. Elevated levels of ROS can induce multiple cellular disruptions, such as cytotoxicity, apoptosis activation and reduced cell function, contributing to tissue deterioration and weakening the structural integrity of bones and tendons. Antioxidants are substances that can prevent or slow down the oxidation process, including Vitamin C, melatonin, resveratrol, anthocyanins and so on, demonstrating potential in treating these overlapping disorders. This comprehensive review aims to elucidate the complex role of oxidative stress within the interlinked pathways of these comorbid conditions. By integrating contemporary research and empirical findings, our objective is to outline new conceptual models and innovative treatment strategies for effectively managing these prevalent diseases. This review underscores the importance of further in-depth research to validate the efficacy of antioxidants and traditional Chinese medicine in treatment plans, as well as to explore targeted interventions focused on oxidative stress as promising areas for future medical advancements.

The Cancer Antioxidant Regulation System in Therapeutic Resistance

Antioxidants play a pivotal role in neutralizing reactive oxygen species (ROS), which are known to induce oxidative stress. In the context of cancer development, cancer cells adeptly maintain elevated levels of both ROS and antioxidants through a process termed “redox reprogramming”. This balance optimizes the proliferative influence of ROS while simultaneously reducing the potential for ROS to cause damage to the cell. In some cases, the adapted antioxidant machinery can hamper the efficacy of treatments for neoplastic diseases, representing a significant facet of the resistance mechanisms observed in cancer therapy. In this review, we outline the contribution of antioxidant systems to therapeutic resistance. We detail the fundamental constituents of these systems, encompassing the central regulatory mechanisms involving transcription factors (of particular importance is the KEAP1/NRF2 signaling axis), the molecular effectors of antioxidants, and the auxiliary systems responsible for NADPH generation. Furthermore, we present recent clinical trials based on targeted antioxidant systems for the treatment of cancer, assessing the potential as well as challenges of this strategy in cancer therapy. Additionally, we summarize the pressing issues in the field, with the aim of illuminating a path toward the emergence of novel anticancer therapeutic approaches by orchestrating redox signaling.

CuCo2O4 Nanoflowers with Multiple Enzyme Activities for Treating Bacterium-Infected Wounds via Cuproptosis-like Death.

Nanozyme-driven catalytic therapy provides a promising treatment strategy for bacterial biofilm-infected wounds. However, the single functionality and limited catalytic efficiency of nanozyme-based materials often restrict the effectiveness of wound infection treatment. In this study, CuCo2O4 nanoflowers with multiple enzymatic activities were prepared for antibacterial/antibiofilm treatment by cuproptosis-like death. CuCo2O4 exhibited peroxidase-like (POD-like) and oxidase-like (OXD-like) dual enzyme activities that generated large amounts of •OH and O2•-. Moreover, the glutathione peroxidase-like (GSH-Px-like) activity of CuCo2O4 was able to reduce the overexpression of GSH in the wound microenvironment, enhancing the therapeutic effects of reactive oxygen species (ROS). The morphology of CuCo2O4 was modified using a hydrothermal method with PEG4000 as the solvent, resulting in the exposure of more active center sites and a significant improvement in enzyme catalytic activity. The in vitro results demonstrated the pronounced disruption effect of CuCo2O4 on biofilms formed by bacteria. In vivo, CuCo2O4 significantly promoted angiogenesis, collagen deposition, and cell proliferation. Transcriptome sequencing revealed that elevated ROS levels in bacteria led to cell membrane damage and metabolic disruption. In addition, Cu2+ overload in bacteria induces lipid peroxidation accumulation and disrupts the respiratory chain and tricarboxylic acid (TCA) cycle, ultimately leading to bacterial cuproptosis-like death. This therapeutic strategy, which combines the synergistic effects of multiple enzyme-like activities with cuproptosis-like death, provides an approach for treating biofilm infections.

Quantitative Factors Introduced in the Feasibility Analysis of Reactive Oxygen Species (ROS)‐Sensitive Triggers

AbstractReactive oxygen species (ROS) are critical for cellular signaling. Various pathophysiological conditions are also associated with elevated levels of ROS. Hence, ROS‐sensitive triggers have been extensively used for selective payload delivery. Such applications are predicated on two key functions: (1) a sufficient magnitude of concentration difference for the interested ROS between normal tissue/cells and intended sites and (2) appropriate reaction kinetics to ensure a sufficient level of selectivity for payload release. Further, ROS refers to a group of species with varying reactivity, which should not be viewed as a uniform group. In this review, we critically analyze data on the concentrations of different ROS species under various pathophysiological conditions and examine how reaction kinetics affect the success of ROS‐sensitive linker chemistry. Further, we discuss different ROS linker chemistry in the context of their applications in drug delivery and imaging. This review brings new insights into research in ROS‐triggered delivery, highlights factors to consider in maximizing the chance for success and discusses pitfalls to avoid.

Quantitative Factors Introduced in the Feasibility Analysis of Reactive Oxygen Species (ROS)-Sensitive Triggers.

Reactive oxygen species (ROS) are critical for cellular signaling. Various pathophysiological conditions are also associated with elevated levels of ROS. Hence, ROS-sensitive triggers have been extensively used for selective payload delivery. Such applications are predicated on two key functions: (1) a sufficient magnitude of concentration difference for the interested ROS between normal tissue/cells and intended sites and (2) appropriate reaction kinetics to ensure a sufficient level of selectivity for payload release. Further, ROS refers to a group of species with varying reactivity, which should not be viewed as a uniform group. In this review, we critically analyze data on the concentrations of different ROS species under various pathophysiological conditions and examine how reaction kinetics affect the success of ROS-sensitive linker chemistry. Further, we discuss different ROS linker chemistry in the context of their applications in drug delivery and imaging. This review brings new insights into research in ROS-triggered delivery, highlights factors to consider in maximizing the chance for success and discusses pitfalls to avoid.

Lipid Variability Induces Endothelial Dysfunction by Increasing Inflammation and Oxidative Stress.

This study investigates the impact of fluctuating lipid levels on endothelial dysfunction. Human aortic and umbilical vein endothelial cells were cultured under varying palmitic acid (PA) concentrations: 0, 50, and 100 μM, and in a variability group alternating between 0 and 100 μM PA every 8 hours for 48 hours. In the lipid variability group, cells were exposed to 100 μM PA during the final 8 hours before analysis. We assessed inflammation using real-time polymerase chain reaction, Western blot, and cytokine enzyme-linked immunosorbent assay (ELISA); reactive oxygen species (ROS) levels with dichlorofluorescin diacetate assay; mitochondrial function through oxygen consumption rates via XF24 flux analyzer; and endothelial cell functionality via wound healing and cell adhesion assays. Cell viability was evaluated using the MTT assay. Variable PA levels significantly upregulated inflammatory genes and adhesion molecules (Il6, Mcp1, Icam, Vcam, E-selectin, iNos) at both transcriptomic and protein levels in human endothelial cells. Oscillating lipid levels reduced basal respiration, adenosine triphosphate synthesis, and maximal respiration, indicating mitochondrial dysfunction. This lipid variability also elevated ROS levels, contributing to a chronic inflammatory state. Functionally, these changes impaired cell migration and increased monocyte adhesion, and induced endothelial apoptosis, evidenced by reduced cell viability, increased BAX, and decreased BCL2 expression. Lipid variability induce endothelial dysfunction by elevating inflammation and oxidative stress, providing mechanistic insights into how lipid variability increases cardiovascular risk.

Interval training suppresses nod-like receptor protein 3 inflammasome activation to improve cardiac function in myocardial infarction rats by hindering the activation of the transforming growth factor-β1 pathway

ObjectiveMyocardial infarction (MI) -induced cardiac dysfunction can be attenuated by aerobic exercises. This study explored the mechanism of interval training (IT) regulating cardiac function in MI rats, providing some theoretical basis for clarifying MI pathogenesis and new ideas for clinically treating MI.MethodsRats were subjected to MI modeling, IT intervention, and treatments of the Transforming growth factor-β1 (TGF-β1) pathway or the nod-like receptor protein 3 (NLRP3) activators. Cardiac function and hemodynamic indicator alterations were observed. Myocardial pathological damage and fibrosis, reactive oxygen species (ROS) level, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities, MDA content, inflammasome-associated protein levels, and inflammatory factor levels were assessed. The binding between TGF-β1 and receptor was detected.ResultsMI rats exhibited decreased left ventricle ejection fraction (LVEF), left ventricle fractional shortening (LVFS), left ventricular systolic pressure (LVSP), positive and negative derivates max/min (dP/dt max/min) and increased left ventricular end-systolic pressure (LVEDP), a large number of scar areas in myocardium, disordered cell arrangement and extensive fibrotic lesions, increased TGF-β1 and receptor binding, elevated ROS level and MDA content and weakened SOD, CAT and GSH-Px activities, and up-regulated NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC) and cleaved-caspase-1 levels, while IT intervention caused ameliorated cardiac function. IT inactivated the TGF-β1 pathway to decrease oxidative stress in myocardial tissues of MI rats and inhibit NLRP3 inflammasome activation. Activating NLRP3 partially reversed IT-mediated improvement on cardiac function in MI rats.ConclusionIT diminished oxidative stress in myocardial tissues and suppressed NLRP3 inflammasome activation via inactivating the TGF-β1 pathway, thus improving the cardiac function of MI rats.

IRE1α regulates ROS and immune responses after UVB irradiation

Objective UV irradiation of the skin induces photo damage and generates cytotoxic intracellular reactive oxygen species (ROS), activating the unfolded protein response (UPR) to adapt or reduce these UVB-mediated damages. This study was designed to understand the role of the UPR mediator IRE1α in the antioxidant response following UVB irradiation of mouse skin and keratinocytes. Methods We used mice with an epidermal deletion of IRE1α and primary mouse keratinocytes to examine effects of UV on different parameters of the antioxidant response in the presence and absence of functional IRE1α. Results In the absence of IRE1α, PERK activity and protein levels are significantly compromised following UVB irradiation. Additionally, the loss of IRE1α suppressed phosphorylation of the PERK target, nuclear factor erythroid-2-related factor 2 (NRF2), and NRF2-dependent antioxidant gene expression after UVB irradiation. Interestingly, IRE1α-deficient keratinocytes exhibit elevated basal ROS levels, while a robust ROS induction upon UVB exposure is abolished. Because UVB-induced ROS plays an essential role in regulating skin inflammation, we analyzed recruited immune cell populations and the expression of pro-inflammatory cytokines, Il-6 and Tnfα, in mice with epidermally targeted deletion of Ire1α. Following UVB irradiation, there was significantly less recruitment of neutrophils and leukocytes and reduced expression of pro-inflammatory cytokine genes in the skin of mice lacking IRE1α. Furthermore, keratinocyte proliferation was also significantly reduced after chronic UVB exposure in the skin of these mice. Conclusion Collectively, our findings indicate that IRE1α is essential for basal and UVB-induced oxidative stress response, UV-induced skin immune responses, and keratinocyte proliferation. Significance statement These findings shed new light on the protective function of IRE1α in the response to UV. IRE1α plays an important role in the regulation of ROS, PERK stability, and antioxidant gene expression in response to UVB in mouse keratinocytes and epidermis.

Gibberellin Positively Regulates Tomato Resistance to Tomato Yellow Leaf Curl Virus (TYLCV).

Tomato yellow leaf curl virus (TYLCV) is a prominent viral pathogen that adversely affects tomato plants. Effective strategies for mitigating the impact of TYLCV include isolating tomato plants from the whitefly, which is the vector of the virus, and utilizing transgenic lines that are resistant to the virus. In our preliminary investigations, we observed that the use of growth retardants increased the rate of TYLCV infection and intensified the damage to the tomato plants, suggesting a potential involvement of gibberellic acid (GA) in the conferring of resistance to TYLCV. In this study, we employed an infectious clone of TYLCV to inoculate tomato plants, which resulted in leaf curling and growth inhibition. Remarkably, this inoculation also led to the accumulation of GA3 and several other phytohormones. Subsequent treatment with GA3 effectively alleviated the TYLCV-induced leaf curling and growth inhibition, reduced TYLCV abundance in the leaves, enhanced the activity of antioxidant enzymes, and lowered the reactive oxygen species (ROS) levels in the leaves. Conversely, the treatment with PP333 exacerbated TYLCV-induced leaf curling and growth suppression, increased TYLCV abundance, decreased antioxidant enzyme activity, and elevated ROS levels in the leaves. The analysis of the gene expression profiles revealed that GA3 up-regulated the genes associated with disease resistance, such as WRKYs, NACs, MYBs, Cyt P450s, and ERFs, while it down-regulated the DELLA protein, a key agent in GA signaling. In contrast, PP333 induced gene expression changes that were the opposite of those caused by the GA3 treatment. These findings suggest that GA plays an essential role in the tomato's defense response against TYLCV and acts as a positive regulator of ROS scavenging and the expression of resistance-related genes.

Cell Membrane-Targeting Type I/II Photodynamic Therapy Combination with FSP1 Inhibition for Ferroptosis-Enhanced Photodynamic Immunotherapy.

An imbalance in reactive oxygen species (ROS) levels in tumor cells can result in the accumulation of lipid peroxide (LPO) which can induce ferroptosis. Moreover, elevated ROS levels in tumors present a chance to develop ROS-based cancer therapeutics including photodynamic therapy (PDT) and ferroptosis. However, their anticancer efficacies are compromised by insufficient oxygen levels and inherent cellular ROS regulatory mechanism. Herein, a cell membrane-targeting photosensitizer, TBzT-CNQi, which can generate 1O2, •OH, and O2 •- via type I/II process to induce a high level of LPO for potent ferroptosis and photodynamic therapy is developed. The FSP1 inhibitor (iFSP1) is incorporated with TBzT-CNQi to downregulate FSP1 expression, lower the intracellular CoQ10 content, induce a high level of LPO, and activate initial tumor immunogenic ferroptosis. In vitro and in vivo experiments demonstrate that the cell membrane-targeting type I/II PDT combination with FSP1 inhibition can evoke strong ICD and activate the immune response, which subsequently promotes the invasion of CD8+ T cells infiltration, facilitates the dendritic cell maturation, and decreases the tumor infiltration of tumor-associated macrophages. The study indicates that the combination of cell membrane-targeting type I/II PDT and FSP1 inhibition holds promise as a potential strategy for ferroptosis-enhanced photodynamic immunotherapy of hypoxia tumors.

Activation of PPARδ in bone marrow endothelial progenitor cells improves their hematopoiesis-supporting ability after myelosuppressive injury

Dysfunctional bone marrow (BM) endothelial progenitor cells (EPCs) with high levels of reactive oxygen species (ROS) are responsible for defective hematopoiesis in poor graft function (PGF) patients with acute leukemia or myelodysplastic neoplasms post-allotransplant. However, the underlying mechanism by which BM EPCs regulate their intracellular ROS levels and the capacity to support hematopoiesis have not been well clarified. Herein, we demonstrated decreased levels of peroxisome proliferator-activated receptor delta (PPARδ), a lipid-activated nuclear receptor, in BM EPCs of PGF patients compared with those with good graft function (GGF). In vitro assays further identified that PPARδ knockdown contributed to reduced and dysfunctional BM EPCs, characterized by the impaired ability to support hematopoiesis, which were restored by PPARδ overexpression. Moreover, GW501516, an agonist of PPARδ, repaired the damaged BM EPCs triggered by 5-fluorouracil (5FU) in vitro and in vivo. Clinically, activation of PPARδ by GW501516 benefited the damaged BM EPCs from PGF patients or acute leukemia patients in complete remission (CR) post-chemotherapy. Mechanistically, we found that increased expression of NADPH oxidases (NOXs), the main ROS-generating enzymes, may lead to elevated ROS level in BM EPCs, and insufficient PPARδ may trigger BM EPC damage via ROS/p53 pathway. Collectively, we found that defective PPARδ contributes to BM EPC dysfunction, whereas activation of PPARδ in BM EPCs improves their hematopoiesis-supporting ability after myelosuppressive therapy, which may provide a potential therapeutic target not only for patients with leukemia but also for those with other cancers.

PagMYB180 regulates adventitious rooting via a ROS/PCD-dependent pathway in poplar

The formation of adventitious roots (AR) is an essential step in the vegetative propagation of economically woody species. Reactive oxygen species (ROS) function as signaling molecules in regulating root growth and development. Here, we identified an R2R3-MYB transcription factor PagMYB180 as a regulator of AR formation in hybrid poplar (Populus alba × Populus glandulosa). PagMYB180 was specifically expressed in the vascular tissues of poplar roots, stems and leaves, and its protein was localized in the nucleus and acted as a transcriptional repressor. Both dominant repression and overexpression of PagMYB180 resulted in a significant reduction of AR quantity, a substantial increase of AR length, and an elevation of both the quantity and length of lateral roots (LR) compared to the wild type (WT) plants. Furthermore, PagMYB180 regulates programmed cell death (PCD) in root cortex cells, which is associated with elevated levels of ROS. Transcriptome and reverse transcription-quantitative PCR (RT-qPCR) analyses revealed that a series of differentially expressed genes are related to ROS, PCD and ethylene synthesis. Taken together, these results suggest that PagMYB180 may regulate AR development via a ROS/PCD-dependent pathway in poplar.

Hydrogen Sulfide Regulates Erectile Function through Stimulation of Antioxidant Defense in the Corpus Cavernosum

Hydrogen sulfide (H2S) is a gaseous cell signaling molecule with vasodilatory properties. Diminished H2S production has been implicated in the pathology of several cardiovascular diseases. H2S may protect against oxidative stress through scavenging of reactive oxygen species (ROS) or through stimulation of the Nrf2-mediated cellular antioxidant defense systems. We have previously demonstrated that mice fed a western diet for 12 weeks develop elevated penile ROS levels and impaired erectile function, which coincides with diminished corpus cavernosal expression of cystathionine γ-lyase (CSE), a major H2S producing enzyme. The objective of this study was to investigate the role of H2S in the regulation of erectile function and penile redox balance. We hypothesized that H2S levels will be positively associated with cellular antioxidant defense and erectile function. Young male C57Bl/6J mice (n = 120) were fed a control diet (CD) or western diet (WD) ad libitum for 18 weeks. For the final six weeks of the dietary intervention, half of the mice were switched to an equivalent diet containing the H2S pro-drug SG1002 at approximately 20 mg/kg/day. Separately, male CSE knockout mice (n = 26) and wild type (WT) littermate controls (n = 26) were fed a standard diet and studied at 6 months. Following the interventions, erectile function was assessed by measuring intracavernosal pressure (ICP) and mean arterial pressure (MAP) during cavernous nerve stimulation (1, 2, 4 V). In separate mice, penile in vivo ROS production was measured via microdialysis. Relative expression of 18 genes related to cellular antioxidant defense were assessed from naïve corpus cavernosum tissue by qRT-PCR. Group differences were determined by two-way ANOVA, with an α-level of 0.05. Erectile function was impaired in CSE KO mice (2V ICP/MAP - WT: 0.70±0.039 vs. KO: 0.55±0.043; p<0.05). Erectile function was similarly impaired in the untreated WD-fed mice (CD: 0.68±0.035 vs. WD: 0.49±0.012; p<0.05), while SG1002 induced a 54% functional restoration in WD mice (WD+SG1002: 0.59±0.019; p<0.05). Penile production of the ROS hydrogen peroxide and superoxide were elevated in CSE KO mice (WT: 0.73±0.04 vs. KO: 1.19±0.13; p<0.01). Penile ROS were also elevated in the WD mice (CD: 0.71±0.07 vs. WD: 1.09±0.15; p<0.01), which were normalized by SG1002 treatment (WD+SG1002: 0.83±0.07; p<0.01 vs. WD). Five antioxidant genes (Gclc, Gpx1, Gpx4, Prdx3, and Hmox1) that were stimulated by SG1002 treatment were also downregulated in CSE KO cavernosal tissues. Conversely, Txnip, a negative regulator of the thioredoxin antioxidant system was suppressed by SG1002 treatment and increased in CSE KO tissues. These results indicate that H2S is a key regulator of the cellular antioxidant systems and ROS balance in the penis, which may also regulate erectile function. Grant number K01DK115540 from the National Institutes of Health. 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.

ISOCITRATE DEHYDROGENASE 2 INHIBITION INDUCES ENDOTHELIAL SENESCENCE BY SUPPRESSION OF MITOPHAGY AND INCREASED ROS PRODUCTION

Objective: Endothelial senescence impairs vascular function and thus is a primary event of age-related vasculature diseases. Isocitrate dehydrogenase 2 (IDH2) plays an important role in inducing alpha-ketoglutarate (alpha-KG) production and preserving mitochondrial function. However, the mechanism and regulation of IDH2 in endothelial senescence have not been elucidated. Design and method: We confirmed vascular endothelial senescence using human umbilical vein endothelial cells(HUVECs) and IDH2 Knockout mouse. Results: We demonstrated that downregulation of IDH2 induced accumulation of miR-34b/c, which impaired mitophagy and elevated mitochondrial reactive oxygen species (ROS) levels by inhibiting mitophagy-related markers (PTEN-induced putative kinase 1 (PINK1), Parkin, LC-II/LC3-I, and p62) and attenuating Sirtuin deacetylation 3 (Sirt3) expression. The mitochondrial dysfunction induced by IDH2 deficiency disrupted cell homeostasis and the cell cycle and led to endothelial senescence. However, miR-34b/c inhibition or alpha-KG supplementation restored Sirt3, PINK1, Parkin, LC-II/LC3-I, p62, and mitochondrial ROS levels, subsequently alleviating endothelial senescence. Conclusions: This study demonstrates that IDH2 deficiency is critical for the suppression of alpha-KG levels, which induced endothelial senescence via miR-34b/c inhibition of mitophagy and mitochondrial ROS elevation in endothelial cells (Figure 7). Therefore, the IDH2/alpha-KG/miR-34b/c axis may provide a potential therapeutic target for age-related vascular diseases.

Development of an alcoholic liver disease model for drug evaluation from human induced pluripotent stem cell-derived liver organoids.

Alcoholic liver disease (ALD) poses a significant health challenge, so comprehensive research efforts to improve our understanding and treatment strategies are needed. However, the development of effective treatments is hindered by the limitation of existing liver disease models. Liver organoids, characterized by their cellular complexity and three-dimensional (3D) tissue structure closely resembling the human liver, hold promise as ideal models for liver disease research. In this study, we use a meticulously designed protocol involving the differentiation of human induced pluripotent stem cells (hiPSCs) into liver organoids. This process incorporates a precise combination of cytokines and small molecule compounds within a 3D culture system to guide the differentiation process. Subsequently, these differentiated liver organoids are subject to ethanol treatment to induce ALD, thus establishing a disease model. A rigorous assessment through a series of experiments reveals that this model partially recapitulates key pathological features observed in clinical ALD, including cellular mitochondrial damage, elevated cellular reactive oxygen species (ROS) levels, fatty liver, and hepatocyte necrosis. In addition, this model offers potential use in screening drugs for ALD treatment. Overall, the liver organoid model of ALD, which is derived from hiPSC differentiation, has emerged as an invaluable platform for advancing our understanding and management of ALD in clinical settings.

Telomerase Reverse Transcriptase Prevents Doxorubicin-induced Microvascular Endothelial Dysfunction

Introduction & Objective: Doxorubicin (Dox) is a frequently used chemotherapeutic known to induce cardiovascular (CV) complications by impairing microvascular- and cardiac function. We previously submitted an abstract showing that Dox-induced microvascular dysfunction preceded Dox-induced cardiac dysfunction and thus microvascular dysfunction might contribute to the damage of the heart itself.>Microvascular function specifically relies upon the adequate release of the vasodilator nitric oxide (NO). Our previous work showed that Telomerase Reverse Transcriptase (TERT), the catalytic subunit of telomerase, is necessary for physiological release of NO to mediate vasodilation. NO suppresses reactive oxygen species (ROS) levels. While Dox correlates with increased ROS production and suppressed TERT activity, attenuated TERT activity may explain the elevated levels of ROS after Dox exposure. The objective of this study was to determine whether TERT transcriptional activation is suffcient to protect against Dox-induced microvascular endothelial- and cardiac dysfunction. We utilized cycloastragenol (CAG) as transcriptional activator. Hypothesis: We hypothesized that TERT transcriptional activation is suffcient to prevent or attenuate Dox-induced endothelial dysfunction. Methods: WT or TERT loss-of-function rats on a Sprague Dawley background were assigned to untreated control-, CAG-, Dox and CAG+Dox groups. Animals were ~14 weeks of age to start the six-week protocol. Dox and CAG+Dox animals received one weekly IP Dox-injection (3x 4mg/kg*BW). CAG administer via diet with 50-60mg of CAG/day*BW. Microvascular function was assessed six-weeks after the first dose of Dox via videomicroscopy. Vasodilator responses to flow (flow-mediated dilation; FMD) and mediators of dilation (NO, H2O2) via fluorescent probes were evaluated. Cardiac function was evaluated using echocardiography. Human microvessels were treated either with 100nM Dox or 1μM CAG or a combination of both. Results: Dox treatment resulted in reduction in FMD in both WT and TERT mutant animals. Smooth-muscle dependent vasodilation was not impaired indicating endothelial impairment. CAG prevented Dox-induced endothelial dysfunction in WT but not TERT mutant rats. AGS499 another activator of TERT showed similar results suggestion a TERT mediated phenotype. Dox-treated WT animals exhibited an increase in H2O2 but not NO production. This phenotype was opposite in CAG+Dox WT animals. TERT mutant animals showed an increase in H2O2 but not NO production even without Dox. To assess which vasodilator mediates dilation to flow, we used L-NAME and PEG-Catalase to block NO- and H2O2, respectively. In CAG+Dox WT animals, L-NAME blocked the vasodilatory response to flow, while PEG-Cat blocked the vasodilatory response non-significantly. Similarly, we observed this protective effect of TERT in the human microcirculation. Human adipose microvessels treated over-night with Dox showed no vasodilatory response to flow while CAG+Dox treated vessels dilated normally similar to untreated control vessels. Smooth muscle function was not affected in neither group. Conclusion: We show evidence that TERT prevents Dox-induced endothelial dysfunction in an in vivo model and using human tissue. We highlight the specificity to TERT by a) using a genetic model lacking normal TERT activity and b) showing similar results using two different compounds which have been shown to activate TERT/promote TERT transcriptional activation. Ultimately, the present data shows that CAG is a potential therapeutic to counteract the detrimental effects of Dox treatment in the CV system via TERT signaling. RO1 HL133029-01. 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.