Redox Signaling Pathways Research Articles

A system-level model reveals that transcriptional stochasticity is required for hematopoietic stem cell differentiation

HSCs differentiation has been difficult to study experimentally due to the high number of components and interactions involved, as well as the impact of diverse physiological conditions. From a 200-node network, that was grounded on experimental data, we derived a 21-node regulatory network by collapsing linear pathways and retaining the functional feedback loops. This regulatory network core integrates key nodes and interactions underlying HSCs differentiation, including transcription factors, metabolic, and redox signaling pathways. We used Boolean, continuous, and stochastic dynamic models to simulate the hypoxic conditions of the HSCs niche, as well as the patterns and temporal sequences of HSCs transitions and differentiation. Our findings indicate that HSCs differentiation is a plastic process in which cell fates can transdifferentiate among themselves. Additionally, we found that cell heterogeneity is fundamental for HSCs differentiation. Lastly, we found that oxygen activates ROS production, inhibiting quiescence and promoting growth and differentiation pathways of HSCs.

Beyond glucose: The crucial role of redox signaling in β-cell metabolic adaptation

ObjectiveRedox signaling mediated by reversible oxidative cysteine thiol modifications is crucial for driving cellular adaptation to dynamic environmental changes, maintaining homeostasis, and ensuring proper function. This is particularly critical in pancreatic β-cells, which are highly metabolically active and play a specialized role in whole organism glucose homeostasis. Glucose stimulation in β-cells triggers signals leading to insulin secretion, including changes in ATP/ADP ratio and intracellular calcium levels. Additionally, lipid metabolism and reactive oxygen species (ROS) signaling are essential for β-cell function and health. MethodsWe employed IodoTMT isobaric labeling combined with tandem mass spectrometry to elucidate redox signaling pathways in pancreatic β-cells. ResultsGlucose stimulation significantly increases ROS levels in β-cells, leading to targeted reversible oxidation of proteins involved in key metabolic pathways such as glycolysis, the tricarboxylic acid (TCA) cycle, pyruvate metabolism, oxidative phosphorylation, protein processing in the endoplasmic reticulum (ER), and insulin secretion. Furthermore, the glucose-induced increase in reversible cysteine oxidation correlates with the presence of other post-translational modifications, including acetylation and phosphorylation. ConclusionsProper functioning of pancreatic β-cell metabolism relies on fine-tuned regulation, achieved through a sophisticated system of diverse post-translational modifications that modulate protein functions. Our findings demonstrate that glucose induces the production of ROS in pancreatic β-cells, leading to targeted reversible oxidative modifications of proteins. Furthermore, protein activity is modulated by acetylation and phosphorylation, highlighting the complexity of the regulatory mechanisms in β-cell function.

Hydrogen peroxide diffusion across the red blood cell membrane occurs mainly by simple diffusion through the lipid fraction

Hydrogen peroxide (H2O2) is an oxidant produced endogenously by several enzymatic pathways. While it can cause molecular damage, H2O2 also plays a role in regulating cell proliferation and survival through redox signaling pathways. In the vascular system, red blood cells (RBCs) are notably efficient at metabolizing H2O2. In addition to a robust antioxidant defense, we recently determined that human RBCs also have a high membrane permeability to H2O2 that is independent of aquaporin 1 or aquaporin 3. In this work, we sought to further investigate the permeation mechanism of H2O2 through the membrane of human RBCs. First, we explored the role of other erythrocytic membrane proteins in H2O2 transport, including urea transporter B and ammonia transporter Rh proteins. However, no differences were found in H2O2 permeability in RBCs lacking these proteins compared to control RBCs. We then focused on the hypothesis that H2O2 diffuses through the lipid bilayer. To test this, we studied H2O2 permeability in RBCs from patients with Gaucher disease (GD), which accumulate sphingolipids in the membrane, affecting RBC morphology and deformability. We found that RBCs from GD patients exhibited lower H₂O₂ membrane permeability. In another approach, we treated normal RBCs with hexanol, which fluidizes the lipid fraction of the RBC membrane, and observed an increase in the permeability to H2O2. In contrast, hexanol had no effect on the rate of water efflux by aquaporin 1. Together, these results support the hypothesis that H2O2 diffusion through the RBC membrane occurs primarily through the lipid fraction.

A mechanistic integration of hypoxia signaling with energy, redox and hormonal cues.

Oxygen deficiency (hypoxia) occurs naturally in many developing plant tissues but can become a major threat during acute flooding stress. Consequently, plants as aerobic organisms must rapidly acclimate to hypoxia and the associated energy crisis to ensure cellular and ultimately organismal survival. In plants, oxygen sensing is tightly linked with oxygen-controlled protein stability of group VII ETHYLENE-RESPONSE FACTORs (ERFVII) which, when stabilized under hypoxia, act as key transcriptional regulators of hypoxia-responsive genes (HRGs). Multiple signaling pathways feed into hypoxia signaling to fine-tune cellular decision making under stress. First, ATP shortage upon hypoxia directly affects the energy status and adjusts anaerobic metabolism. Secondly, altered redox homeostasis leads to reactive oxygen and nitrogen species (ROS and RNS) accumulation, evoking signaling and oxidative stress acclimation. Finally, the phytohormone ethylene promotes hypoxia signaling to improve acute stress acclimation, while hypoxia signaling in turn can alter ethylene, auxin, abscisic acid, salicylic acid and jasmonate signaling to guide development and stress responses. In this Update, we summarize the current knowledge on how energy, redox and hormone signaling pathways are induced under hypoxia and subsequently integrated at the molecular level to ensure stress-tailored cellular responses. We show that some HRGs are responsive to changes in redox, energy and ethylene independently of the oxygen status, and propose an updated HRG list that is more representative for hypoxia marker gene expression. We discuss the synergistic effects of hypoxia, energy, redox and hormone signaling and their phenotypic consequences in the context of both environmental and developmental hypoxia.

Dark Anaerobic Conditions Induce a Fast Induction of the Xanthophyll Cycle in Chlamydomonas reinhardtii When Exposed to High Light.

Dark anaerobiosis promotes the acidification of the thylakoid lumen and a reduction in the plastoquinone (PQ) pool. The relationship between the reduction in the PQ pool in the dark and the induction of the xanthophyll cycle under high light stress was investigated in Chlamydomonas reinhardtii. To achieve a comprehensive oxidative/reductive (aerobic/anaerobic conditions) state of the PQ pool, cultures were bubbled with air or nitrogen for 4 h. To induce the xanthophyll cycle, the cultures were then irradiated with 1200 µmolphotons m-2 s-1 white light for 1 h. The anaerobic cultures exhibited a stronger induction of the xanthophyll cycle with a 3.4-fold higher de-epoxidation state than the aerobic cultures. Chlorophyll fluorescence measurements showed that this response was influenced by the previous redox state of the PQ pool, and that dark anaerobiosis triggers physiological responses, such as exposure to high light. Thus, the photosynthetic apparatus in anaerobic cultures was already alerted, at the moment of high light exposure, to give an appropriate response to the stress with a stronger induction of the xanthophyll cycle than in aerobic cultures. Our results provide new information on the importance of the redox signaling pathway and highlight the importance of the reductive conditions of the PQ pool in regulating the physiological responses of photosynthetic organisms to stress.

New Emerging Therapeutic Strategies Based on Manipulation of the Redox Regulation Against Therapy Resistance in Cancer.

Background: Resistance to standard therapeutic methods, including chemotherapy, immunotherapy, and targeted therapy, remains a critical challenge in effective cancer treatment. Redox homeostasis modification has emerged as a promising approach to address medication resistance. Objective: This review aims to explore the mechanisms of redox alterations and signaling pathways contributing to treatment resistance in cancer. Methods: In this study, a comprehensive review of the molecular mechanisms underlying drug resistance governed by redox signaling was conducted. Emphasis was placed on understanding how tumor cells manage increased reactive oxygen species (ROS) levels through upregulated antioxidant systems, enabling resistance across multiple therapeutic pathways. Results: Key mechanisms identified include alterations in drug efflux, target modifications, metabolic changes, enhanced DNA damage repair, stemness preservation, and tumor microenvironment remodeling. These pathways collectively facilitate tumor cells' adaptive response and resistance to various cancer treatments. Conclusion: Developing a detailed understanding of the interrelationships between these redox-regulated mechanisms and therapeutic resistance holds potential to improve treatment effectiveness, offering valuable insights for both fundamental and clinical cancer research. Antioxid. Redox Signal. 00, 000-000.

Exploring the Role of Cuprotosis-Associated Genes in Cancer Progression and Therapy Resistance: A Comprehensive Analysis across Multiple Cancer Types

This review presents a comprehensive overview of the role of cuprotosis-associated genes in various cancer types, highlighting their significance in tumor progression and therapy resistance. In breast cancer and colorectal cancer (CRC), dysregulation of genes involved in mitochondrial function and copper metabolism, such as FDX1, LIAS, LIPT1, DLD, DLAT, and PDHA1/PDHB, promotes metabolic reprogramming and enhances cancer cell survival. Ovarian cancer exhibits unique dysregulations in genes like ATP7B, CCS, and COMMD1, influencing copper metabolism and redox signaling pathways, thereby contributing to chemoresistance and tumor growth. Head and neck cancer involves upregulation of MT1X, ATP7A, and CCS, potentially aiding cancer cell survival under oxidative stress conditions. Lung cancer is characterized by distinct dysregulation of genes like SLC31A1, ATOX1, and COMMD1, modulating copper homeostasis and redox signaling to support tumor proliferation. Liver cancer and kidney cancer each present unique sets of dysregulated cuprotosis-associated genes, such as SLC39A4, SCO2, and ATP7A, suggesting novel therapeutic targets specific to these cancer types. Pathway analysis reveals enrichment in mineral absorption pathways, emphasizing the importance of these genes in maintaining cellular mineral homeostasis. Understanding the intricate interplay between cuprotosis-associated genes and cancer biology offers insights into potential therapeutic strategies targeting copper metabolism for improved treatment outcomes across various cancer types.

Regulatory roles of NAMPT and NAD+ metabolism in uterine leiomyoma progression: Implications for ECM accumulation, stemness, and microenvironment

Uterine leiomyoma (UL), commonly referred to as benign tumors, is characterized by excessive cell proliferation, extracellular matrix (ECM) accumulation, and the presence of stem cell-like properties. Nicotinamide adenine dinucleotide (NAD+) metabolism, regulated in part by nicotinamide phosphoribosyltransferase (NAMPT), plays a crucial role in these pathological processes and has emerged as a potential therapeutic target. Additionally, redox signaling pathways are integral to the pathogenesis of UL, influencing the dynamics of NAD+ metabolism. This study sought to elucidate the regulatory functions of NAMPT and NAD+ metabolism, in conjunction with redox signaling, in the progression of UL, and to explore potential therapeutic strategies targeting these pathways. Evaluation of NAMPT expression in human UL tissues revealed a positive correlation between elevated NAMPT levels and increased ECM deposition, as well as the expression of stemness markers. The use of FK866 and nicotinamide (NAM), to inhibit NAMPT significantly suppressed UL cell viability and attenuated stem cell-like characteristics. Redox signaling pathways, including those associated with DNA damage, lysosomal function homeostasis, and redox-sensitive phagophore formation, were implicated in the regulation of ECM dynamics, particularly through ECM-targeted inhibition. This study highlights the pivotal roles of NAMPT, NAD+ metabolism, and redox signaling in the pathophysiology of UL. Targeting NAMPT, particularly through the use of inhibitors FK866 and NAM, represents a promising therapeutic approach for mitigating UL progression by modulating redox and ECM dynamics. These findings offer novel insights into UL pathogenesis and establish NAMPT as a compelling target for future clinical investigation.

Mitochondrial Dynamics Drive Muscle Stem Cell Progression from Quiescence to Myogenic Differentiation.

From quiescence to activation and myogenic differentiation, muscle stem cells (MuSCs) experience drastic alterations in their signaling activity and metabolism. Through balanced cycles of fission and fusion, mitochondria alter their morphology and metabolism, allowing them to affect their decisive role in modulating MuSC activity and fate decisions. This tightly regulated process contributes to MuSC regulation by mediating changes in redox signaling pathways, cell cycle progression, and cell fate decisions. In this review, we discuss the role of mitochondrial dynamics as an integral modulator of MuSC activity, fate, and maintenance. Understanding the influence of mitochondrial dynamics in MuSCs in health and disease will further the development of therapeutics that support MuSC integrity and thus may aid in restoring the regenerative capacity of skeletal muscle.

Targeting the Main Sources of Reactive Oxygen Species Production: Possible Therapeutic Implications in Chronic Pain.

Humans have long been combating chronic pain. In clinical practice, opioids are firstchoice analgesics, but long-term use of these drugs can lead to serious adverse reactions. Finding new, safe and effective pain relievers that are useful treatments for chronic pain is an urgent medical need. Based on accumulating evidence from numerous studies, excess reactive oxygen species (ROS) contribute to the development and maintenance of chronic pain. Some antioxidants are potentially beneficial analgesics in the clinic, but ROS-dependent pathways are completely inhibited only by scavenging ROS directly targeting cellular or subcellular sites. Unfortunately, current antioxidant treatments do not achieve this effect. Furthermore, some antioxidants interfere with physiological redox signaling pathways and fail to reverse oxidative damage. Therefore, the key upstream processes and mechanisms of ROS production that lead to chronic pain in vivo must be identified to discover potential therapeutic targets related to the pathways that control ROS production in vivo. In this review, we summarize the sites and pathways involved in analgesia based on the three main mechanisms by which ROS are generated in vivo, discuss the preclinical evidence for the therapeutic potential of targeting these pathways in chronic pain, note the shortcomings of current research and highlight possible future research directions to provide new targets and evidence for the development of clinical analgesics.

Unveiling the role of epigenetic mechanisms and redox signaling in alleviating multiple abiotic stress in plants.

Anthropogenic activities and subsequent global climate change instigate drastic crop productivity and yield changes. These changes comprise a rise in the number and severity of plant stress factors, which can arise simultaneously or sequentially. When abiotic stress factors are combined, their impact on plants is more substantial than that of a singleton stress factor. One such impact is the alteration of redox cellular homeostasis, which, in turn, can regulate downstream stress-responsive gene expression and resistance response. The epigenetic regulation of gene expression in response to varied stress factors is an interesting phenomenon, which, conversely, can be stable and heritable. The epigenetic control in plants in response to abiotic stress combinations and their interactions with cellular redox alteration is an emerging field to commemorate crop yield management under climate change. The article highlights the integration of the redox signaling pathways and epigenetic regulations as pivotal components in the complex network of plant responses against multi-combinatorial stresses across time and space. This review aims to lay the foundation for developing novel approaches to mitigate the impact of environmental stresses on crop productivity, bridging the gap between theoretical understanding and practical solutions in the face of a changing climate and anthropogenic disturbances.

The Role of Redox Environment in Tumors.

Reactive Oxygen Species (ROS) and the redoxin system regulate the redox environment. Thus, they mediate various physiological and pathological processes involved in tumor occurrence and development by activating redox-sensitive genes and regulating redox signaling pathways, including tumor cell proliferation, migration, invasion, and various cell death types. Therefore, the mechanism underlying redox environment regulation must be clarified to accurately target this mechanism and improve the effect of tumor treatment. This review introduces redox-sensitive transcription factors and their activated downstream signaling pathways, and the application of inhibitors targeting related transcription factors in tumor therapy.

Physiological and transcriptomic changes of zebrafish (Danio rerio) in response to Isopropylate Triphenyl Phosphate (IPPP) exposure

Isopropylate Triphenyl Phosphate (IPPP), a novel organophosphorus flame retardant, has become a widespread environmental pollutant. However, the toxic effects and mechanisms of IPPP remain unclear. In this study, we evaluated the neurodevelopmental toxicity effects of IPPP on zebrafish embryonic development, neurobehavior, and physiological and transcriptomic changes. The results showed that IPPP induced adverse developments such as low survival rates and hatching rates, decreased body length and eye distance, and also led to increased heart rates and embryonic malformation rates. The developmental defects mainly included typical pericardial edema, eye deformities, and a reduction in the number of newborn neurons. Mitochondrial energy metabolism disorders and apoptosis of cardiomyocytes may be responsible for heart malformation. Behavioral results showed that IPPP caused abnormal changes in swimming speed, total swimming distance and trajectory, and showed a low-dose effect. In addition, the decreased activity of neurotransmitters such as acetylcholinesterase (AchE) and dopamine (DA), and the changes in genes related to the central nervous system (CNS) and metabolism pathway may be the causes of neurodevelopmental toxicity of IPPP. Meanwhile, IPPP induced oxidative stress and apoptosis, and changed the ATPase activity of zebrafish larvae by altering nuclear factor erythroid2-related factor 2 (Nrf2) and mitochondrial signaling pathways, respectively. Transcriptome sequencing results indicated that Cytochrome P450 and drug metabolism, Energy metabolism-related pathways, Glutathione metabolism, Retinoid acid (RA) and REDOX signaling pathways were significantly enriched, and most of the genes in these pathways were up-regulated after IPPP treatment, which may be new targets for IPPP-induced neurodevelopment. In summary, the results of this study provide an important reference for a comprehensive assessment of the toxic effects and health risks of the new pollutant IPPP.

The Emerging Role of Herbal Medicines in Cancer by Interfering with Posttranslational Modifications.

Significance: Herbal medicines have a long history of comprehensive cancer treatment through various posttranslational modifications (PTMs). Recently, emerging evidence revealed that dysregulation of reactive oxygen species (ROS) and ROS-regulated signaling pathways influence cancer initiation, growth, and progression in a paradoxical role with either low levels or increasing levels of basal ROS. However, ROS-triggered modifications of target proteins in the face of ROS-mediated signal transduction are not fully understood in the anticancer therapies of herbal medicines. In this review, we briefly introduce the PTM-dependent regulations of herbal medicines, and then focus on the current ideals that targeting ROS-dependent PTMs via antioxidant and redox signaling pathways can provide a promising strategy in herbal-based anticancer effects. Recent Advances: Advanced development in highly sensitive mass spectrometry-based techniques has helped utilize ROS-triggered protein modifications in numerous cancers. Accumulating evidence has been achieved in laboratory to extensively ascertain the biological mechanism of herbal medicines targeting ROS in cancer therapy. Two general mechanisms underlining ROS-induced cell signaling include redox state and oxidative modification of target protein, indicating a new perspective to comprehend the intricate dialogues between herbal medicines and cancer cellular contexts. Critical Issues: Complex components of herbal medicines limit the benefits of herbal-based cancer therapies. In this review, we address that ROS-dependent PTMs add a layer of proteomic complexity to the cancer through altering the protein structure, expression, function, and localization. Elaborating ROS-triggered PTMs implicated in cell signaling, apoptosis, and transcriptional regulation function, and the possible cellular signaling, has provided important information about the contribution of many ROS targeting herbal therapies in anticancer effects. Continued optimization of proteomic strategies for PTM analysis in herbal medicines is also briefly discussed. Future Directions: Rigorous evaluations of herbal medicines and proteomic strategies are necessary to explore the aberrant regulation of ROS-triggered antioxidant and redox signaling contributing to the novel protein targets and herbal-associated pharmacological issues. These efforts will eventually help develop more herbal drugs as modern therapeutic agents.

Rasagiline Exerts Neuroprotection towards Oxygen-Glucose-Deprivation/Reoxygenation-Induced GAPDH-Mediated Cell Death by Activating Akt/Nrf2 Signaling.

Rasagiline (Azilect®) is a selective monoamine oxidase B (MAO-B) inhibitor that provides symptomatic benefits in Parkinson's disease (PD) treatment and has been found to exert preclinical neuroprotective effects. Here, we investigated the neuroprotective signaling pathways of acute rasagiline treatment for 22 h in PC12 neuronal cultures exposed to oxygen-glucose deprivation (OGD) for 4 h, followed by 18 h of reoxygenation (R), causing 40% aponecrotic cell death. In this study, 3-10 µM rasagiline induced dose-dependent neuroprotection of 20-80%, reduced the production of the neurotoxic reactive oxygen species by 15%, and reduced the nuclear translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by 75-90%. In addition, 10 µM rasagiline increased protein kinase B (Akt) phosphorylation by 50% and decreased the protein expression of the ischemia-induced α-synuclein protein by 50% in correlation with the neuroprotective effect. Treatment with 1-5 µM rasagiline induced nuclear shuttling of transcription factor Nrf2 by 40-90% and increased the mRNA levels of the antioxidant enzymes heme oxygenase-1, (NAD (P) H- quinone dehydrogenase, and catalase by 1.8-2.0-fold compared to OGD/R insult. These results indicate that rasagiline provides neuroprotection to the ischemic neuronal cultures through the inhibition of α-synuclein and GAPDH-mediated aponecrotic cell death, as well as via mitochondrial protection, by increasing mitochondria-specific antioxidant enzymes through a mechanism involving the Akt/Nrf2 redox-signaling pathway. These findings may be exploited for neuroprotective drug development in PD and stroke therapy.

Targeting ROS in cancer: rationale and strategies.

Reactive oxygen species (ROS) in biological systems are transient but essential molecules that are generated and eliminated by a complex set of delicately balanced molecular machineries. Disruption of redox homeostasis has been associated with various human diseases, especially cancer, in which increased ROS levels are thought to have a major role in tumour development and progression. As such, modulation of cellular redox status by targeting ROS and their regulatory machineries is considered a promising therapeutic strategy for cancer treatment. Recently, there has been major progress in this field, including the discovery of novel redox signalling pathways that affect the metabolism of tumour cells as well as immune cells in the tumour microenvironment, and the intriguing ROS regulation of biomolecular phase separation. Progress has also been made in exploring redox regulation in cancer stem cells, the role of ROS in determining cell fate and new anticancer agents that target ROS. This Review discusses these research developments and their implications for cancer therapy and drug discovery, as well as emerging concepts, paradoxes and future perspectives.

A novel AIE fluorescent probe for the detection and imaging of hydrogen peroxide in living tumor cells and in vivo

Hydrogen peroxide (H2O2), a key reactive oxygen species (ROS), plays crucial roles in redox signaling pathways and immune responses associated with cell proliferation, differentiation, migration, and disease progression. The selective monitoring of overproduced H2O2 is important for understanding the diagnosis and pathogenesis of diseases such as cardiovascular disease, cancers, diabetes, Parkinson’s disease, Alzheimer’s disease, and inflammation. In this paper, an AIE fluorescent probe BQM-H2O2 was developed by connecting phenyl borate with the fluorophore BQM-PNH for selective detection of H2O2. In the presence of H2O2 at fw = 99% (pH = 7.4, 1% DMSO), the probe BQM-H2O2 could generate strong fluorescent signals due to the oxidation of the borate ester. The probe exhibited high selectivity and a low detection limit toward H2O2 with the calculated LOD of 112.6 nM. Importantly, it was employed in the detection of exogenous and endogenous hydrogen peroxide in 4T1 cells with low cytotoxicity. This probe has also been successfully applied to imaging of H2O2 in Blab/c mice bearing 4T1 graft tumors.

Aging-associated Aberrant Mitochondrial Redox Signaling, Physical Activity, and Sarcopenia.

Aging-related alteration of mitochondrial morphology, impairment in metabolic capacity, bioenergetics, and biogenesis are closely associated with loss of muscle mass and function. Mitochondrial Reactive Oxygen Species (ROS) stimulate muscular redox signaling mechanisms. Bioenergetic integrity of mitochondria and redox signaling dynamics deteriorates in aged skeletal muscle. Mitochondrial bioenergetic impairment leads to excessive ROS levels and induces the generation of defective mitochondria. Higher ROS levels may induce senescence or apoptosis. It is not a resolved issue that mitochondrial dysfunction is either the sole reason or a consequence of muscle loss (or both). However, Increasing evidence emphasizes that dysregulated mitochondrial redox signaling has a central role in age-related muscle loss. Nuclear factor erythroid 2-related factor 2 (Nrf2) regulates redox signaling pathways with the expression of antioxidant genes. As the aberrant redox signaling mechanisms in aging skeletal muscle become clearer, new natural and synthetic Nrf2-modulating substances and integrated daily physical activity alternatives are coming into view for preventing muscle loss in the elderly. A comprehensive understanding of the relationship between redox signaling pathways and age-related sarcopenia can help us to prevent sarcopenia and its frailty effects with an optimized exercise program as an innovative non-pharmacological therapeutic approach. A further aspect is necessary to consider both individualized physical training options and alternative Nrf2 signaling modulators. Ameliorating the redox signaling with physical activity and pharmacological interventions may help to prevent sarcopenia and its frailty effects.

Tweaking the NRF2 signaling cascade in human myelogenous leukemia cells by artificial nano-organelles

NRF2 (nuclear factor erythroid-2-related factor 2) is a key regulator of genes involved in the cell's protective response to oxidative stress. Upon activation by disturbed redox homeostasis, NRF2 promotes the expression of metabolic enzymes to eliminate reactive oxygen species (ROS). Cell internalization of peroxisome-like artificial organelles that harbor redox-regulating enzymes was previously shown to reduce ROS-induced stress and thus cell death. However, if and to which extent ROS degradation by such nanocompartments interferes with redox signaling pathways is largely unknown. Here, we advance the design of H2O2-degrading artificial nano-organelles (AnOs) that exposed surface-attached cell penetrating peptides (CPP) for enhanced uptake and were equipped with a fluorescent moiety for rapid visualization within cells. To investigate how such AnOs integrate in cellular redox signaling, we engineered leukemic K562 cells that report on NRF2 activation by increased mCherry expression. Once internalized, ROS-metabolizing AnOs dampen intracellular NRF2 signaling upon oxidative injury by degrading H2O2. Moreover, intracellular AnOs conferred protection against ROSinduced cell death in conditions when endogenous ROS-protection mechanisms have been compromised by depletion of glutathione or knockdown of NRF2. We demonstrate CPP-facilitated AnO uptake and AnO-mediated protection against ROS insults also in the T lymphocyte population of primary peripheral blood mononuclear cells from healthy donors. Overall, our data suggest that intracellular AnOs alleviated cellular stress by the on-site reduction of ROS.

Diabetic Retinopathy: New Treatment Approaches Targeting Redox and Immune Mechanisms.

Diabetic retinopathy (DR) represents a severe complication of diabetes mellitus, characterized by irreversible visual impairment resulting from microvascular abnormalities. Since the global prevalence of diabetes continues to escalate, DR has emerged as a prominent area of research interest. The development and progression of DR encompass a complex interplay of pathological and physiological mechanisms, such as high glucose-induced oxidative stress, immune responses, vascular endothelial dysfunction, as well as damage to retinal neurons. Recent years have unveiled the involvement of genomic and epigenetic factors in the formation of DR mechanisms. At present, extensive research explores the potential of biomarkers such as cytokines, molecular and cell therapies, antioxidant interventions, and gene therapy for DR treatment. Notably, certain drugs, such as anti-VEGF agents, antioxidants, inhibitors of inflammatory responses, and protein kinase C (PKC)-β inhibitors, have demonstrated promising outcomes in clinical trials. Within this context, this review article aims to introduce the recent molecular research on DR and highlight the current progress in the field, with a particular focus on the emerging and experimental treatment strategies targeting the immune and redox signaling pathways.