Free Radical Biology and Medicine

Oxidative post-translational modifications on the sulfhydryl group of cysteines can occur spontaneously or enzymatically. The dioxygenation of N-terminal cysteines has emerged as a new oxygen sensing paradigm, catalysed by 2-aminoethanethiol dioxygenase (ADO) in mammals. Conflicting evidence has been reported in recent years on whether this reaction can occur in the absence of ADO. Here we sought to address whether physiological oxidative stress can interfere with ADO-catalysed N-terminal dioxygenation. Using a system to produce titratable intracellular levels of H2O2, we demonstrate that the stability of RGS4 and 5 is not affected by oxidative stress, whether ADO is present or not. However, cytotoxic levels of oxidative stress did induce an increase in RGS4/5 protein levels that occurred independently of the Cys N-degron pathway. This effect of tBHP was reduced by Fe2+ chelation and perturbations of lysosomal function, suggesting the possible involvement of ferroptosis. We conclude that N-terminal cysteine dependent proteolysis of RGS4/5 is not sensitive to physiological oxidative stress, but these proteins can be stabilised during the process of oxidative stress-induced cell death through an N-terminal cysteine independent mechanism.

Glutathione peroxidase 4 (GPX4) is an antioxidant enzyme important for the reduction of toxic lipid peroxide products. Previous studies revealed the importance of mouse Gpx4 in protecting cardiomyocytes from ferroptosis and, subsequently, the development of cardiovascular disease. In this paper, we investigate the transcriptional consequences of cardiac-specific deletion of Gpx4 in mice and compare this response with that observed in human cardiomyopathy. The findings in this study highlight the importance of GPX4 in maintaining both structural and functional stability of the heart and identify key pathway changes resulting from excessive ferroptosis in cardiac tissue. By overlapping common transcriptional programs perturbed in this animal model and human cardiomyopathy, our findings identify putative mechanisms through which ferroptosis contributes to the development and progression of heart disease. These studies may help guide future cardiovascular therapeutics targeting ferroptosis-dependent pathways.

Ferredoxins are central to cellular metabolism by mediating electron flow in energy conversion reactions. The focus of this study was to systematically examine twelve ferredoxin and ferredoxin-like proteins from Synechocystis sp. PCC 6803 to identify their properties, activities, and functions in electron transfer. Using electron paramagnetic resonance spectroscopy, we detected cluster types consistent with major ferredoxin families including plant-type [2Fe-2S], adrenodoxin, thioredoxin, and bacterial-type [4Fe- 4S] ferredoxins. In addition, we found that the ssr3184 ferredoxin-like protein exchanged between a [3Fe-4S] or a [4Fe-4S] cluster, pointing to a possible functional change in response to changes in oxygen or cellular redox poise. Electrochemical measurements demonstrated that these ferredoxins constitute a broad potential window, from -243 mV to -520 mV vs SHE. Investigations on their capacity to support electron-transfer focused on reactions with two major redox hubs: Photosystem I and pyruvate:ferredoxin oxidoreductase and included testing of binding interactions with nitrite reductase. Expression profiling under multiple environmental conditions was also used to predict function and revealed distinct regulatory patterns. Collectively, these findings identified a group of core ferredoxins that directly support photosynthetic electron transfer, and more specialized ones that may serve other functions. In summary, Synechocystis utilizes a suite of ferredoxins to maintain cellular redox homeostasis under dynamic environmental conditions.

Reactive oxygen species (ROS) are central signaling molecules in many biological processes by inducing oxidative modifications of protein cysteine residues, including S-glutathionylation. Increasing evidence supports that ROS contribute to cancer progression via promoting cancer cell migration, invasion, and metastasis. Nevertheless, the protein targets of S-glutathionylation that regulate cancer cell motility remain ill-defined. In this study, we report on the redox regulation of ARHGEF7, a guanine nucleotide exchange factor highly expressed in metastatic cancer cells, that plays a major role in regulating cell migration. Our data demonstrates that ARHGEF7 is selectively glutathionylated at the highly conserved C312 residue in its PH domain, which is implicated in regulating its enzymatic activity. Breast cancer cell lines showed increased cell migration and invasion upon glutathionylation of ARHGEF7 at C312 in response to both oxidative stress and epidermal growth factor (EGF). Mechanistically, upon C312 glutathionylation, ARHGEF7 exhibited significantly enhanced binding to Rac1 and increased Rac1 recruitment to the cell membrane and lamellipodia. ARHGEF7 S-glutathionylation also increased its enzymatic rate of GDP-GTP nucleotide exchange, resulting in Rac1 activation. Consequently, ARHGEF7 C312 S-glutathionylation induced Rac1-PAK1 activation and their downstream pathways, including LIMK1 and MEK1, thereby enhancing migration and invasion. Our data reveal a new redox player in cell migration, with its potential implications for ROS-induced cancer progression.

Organic germanium, particularly carboxyethyl germanium sesquioxide (Ge-132), has been investigated for decades in relation to diverse biological effects, with a strong emphasis on its antioxidant properties. However, the available literature remains dispersed, encompassing heterogeneous experimental models and endpoints that limit mechanistic interpretation. While antiglycative activity has been described at the biochemical level, its downstream gene regulatory consequences under glycative stress remain inconsistently characterized. Here, we combined systematic review of the literature of experimental studies with targeted molecular analysis in a standardized cellular model. The literature mapping was used to guide pathway selection rather than to establish quantitative associations. Based on patterns emerging from literature, we focused on pathways associated with glycative stress responses, including carbonyl stress, inflammatory signaling, and autophagy regulation. Gene expression analysis revealed a limited and selective modulation of regulatory pathways under glycative stress conditions, consistent with a context-dependent effect rather than broad transcriptional reprogramming. In parallel, protein analysis showed reduced intracellular accumulation of advanced glycation end products (AGEs) in Ge-132-treated cells under glycative stress conditions. Importantly, these findings support a dissociation between glycative damage reduction and cellular stress-response pathways. This combined approach helps interpretation of previously fragmented observations across the literature and highlights gene regulation under glycative stress as a relevant but still unresolved aspect of organogermanium biology.

A method to measure telomere length in S. cerevisiae was developed based on bioluminescence resonance energy transfer (BRET). The system uses energy transfer between a luciferase-Rif2 fusion protein and fluorescently tagged Rap1. The study demonstrates that the BRET ratio correlates with the Rap1/Rif2 complex at the telomeres and thus the availability of telomeric Rap1 binding sites. This enables the measurement of telomere length in living cells. The system was able to reproduce reported deviations in telomere length in mutants lacking telomere length regulators, cells treated with telomere length modifying compounds and strains expressing inducible telomerase. The BRET ratio linearly correlated with the average number of telomeric nucleotides derived from long-read sequencing data using a novel algorithm for telomere length calculation. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/711003v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1850c4dorg.highwire.dtl.DTLVardef@1ead295org.highwire.dtl.DTLVardef@1a76358org.highwire.dtl.DTLVardef@6b3183_HPS_FORMAT_FIGEXP M_FIG C_FIG

Rhodiola rosea is a traditional medicinal plant often classified as an adaptogen, with reported effects in supporting the bodys response to physical, environmental, and emotional stressors. The present study investigated the antioxidant properties of Rhodiola rosea extract and its major chemical constituents to provide insight into their potential mechanisms of action. Through in vitro biochemical assays, we demonstrated that Rhodiola rosea extract has the capacity to reduce hydrogen peroxide (H2O2) levels. Among its primary chemical components, rosavin significantly decreased H2O2, whereas salidroside had no effect. Neither compound affected superoxide levels. Structural analysis revealed that the intact phenylpropanoid glycoside architecture of rosavin is required for activity, as its individual components, arabinose and rosin, showed no inhibitory effect. Further investigation demonstrated that rosavin attenuates H2O2-mediated oxidation of thiol groups, supporting a role in cellular redox regulation. In cultured human cells, rosavin mitigated reductions in cell viability induced by exposure to H2O2, indicating cytoprotective effects under oxidative stress conditions. Finally, in an in vivo model, administration of SARS-CoV-2 spike protein increased circulating levels of H2O2, which were subsequently reduced following rosavin treatment. Collectively, these findings identify rosavin as a structurally dependent antioxidant component of Rhodiola rosea that modulates H2O2-associated oxidative stress and supports further investigation of phenylpropanoid glycosides as adaptogens.

Careful balance of the redox status of the embryo and reduction of oxidative stress is crucial in early development. Here we show that the culture of preimplantation mouse embryos in the conditionally non-essential amino acid L-proline (Pro) increases the intracellular concentration of the potent antioxidant glutathione as shown by staining of 2-cell, 4-cell and 8-cell embryos with tetrafluoroterephthalonitrile (4F-2CN). Further, liquid-chromatography/mass spectrometry showed increased GSH levels in all Pro-treated preimplantation stages of development compared to controls. The GSH:GSSG ratio also showed a Pro-dependent increase. Overall, our results indicate that the beneficial effect of Pro in preimplantation embryo culture is due to the reduction in oxidative stress mediated through an increase in cellular GSH concentration.

PurposeAlanine transaminases (ALT), encoded by the GPT gene, catalyzes the reversible conversion of pyruvate and glutamate to alanine and alpha-ketoglutarate, thereby correlating carbohydrate and amino acid metabolism. However, its role in the human neural retina remains unclear. This study aimed to explore the expression, localization, and metabolic function of ALT in the human neural retina and its potential involvement in retinal diseases. MethodsALT1 and ALT2 expression and localization were examined in the retinas of healthy and diabetic retinopathy (DR) donors via immunoblotting and immunofluorescence. ALT function was assessed in ex vivo human retinal explants using pharmacological inhibition with beta-chloro-L-alanine (BCLA), followed by the analyses of enzyme activity, tissue injury, and transcriptomic responses. Stable-isotope tracing with 13C-and 15N-labelled substrates combined with GC-MS was used to define ALT-dependent carbon and nitrogen fluxes in macular and peripheral retinas. Redox level (NADPH/NADP+) was also evaluated under tert-butyl hydroperoxide-induced oxidative stress. ResultsALT1 and ALT2 were both expressed in the human neural retina, with prominent localization in Muller glia and photoreceptor inner segments. ALT1 displayed a diffuse cytoplasmic distribution, whereas ALT2 demonstrated a punctate pattern consistent with mitochondrial localization. In DR retinas, ALT1 expression was spatially disorganized and heterogeneous, while ALT2 remained comparatively preserved. Inhibition of ALT with BCLA markedly reduced ALT activity without causing overt cytotoxicity or major transcriptional changes. Isotope tracing demonstrated that retinal ALT predominantly channels pyruvate-derived carbon into alanine, whereas alanine was minimally contributed to pyruvate production under basal conditions. ALT inhibition suppressed alanine synthesis and release, redirected nitrogen flux towards glutamate, glutamine, and aspartate, and uncovered distinct metabolic adaptations in macular but not peripheral retinas. Under oxidative stress, ALT inhibition induced the decrease of NADP+/NADPH ratio and LDH release, indicating improved redox balance and reduced tissue injury. ConclusionsALT is previously unrecognized as a regulator of carbon and nitrogen partitioner in the human neural retina, contributing to redox homeostasis under stress. The altered distribution of ALT1 in DR retina and the protective metabolic effects of ALT inhibition suggest ALT as a potential contributor to retinal metabolic vulnerability and a candidate therapeutic target in retinal diseases.

Cardiac transthyretin amyloidosis (ATTR-CA) is caused by myocardial deposition of misfolded transthyretin, leading to progressive heart failure. Disease pathology, however, extends beyond passive amyloid deposition and also involves active processes such as extracellular matrix (ECM) remodeling and immune activation. Mass spectrometry (MS) is the gold standard for amyloid typing in diagnostics. Here, we applied quantitative MS-driven proteomics on formalin-fixed paraffin-embedded whole cardiac tissue sections from six ATTR-CA cases, ten unaffected controls and four AL-CA controls to investigate protein expression changes. In addition to transthyretin, over 500 proteins were upregulated in ATTR-CA biopsies, including complement and coagulation factors as well as extracellular matrix (ECM) remodeling proteins. Among these, members of the A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) family, metalloproteinases (MMPs), and Tissue Inhibitor of Metalloproteinases (TIMP3) showed significant upregulation. These proteins are key regulators of ECM turnover and structural integrity. Immunohistochemistry confirmed ADAMTS4 enrichment in amyloid deposits, while TIMP3 showed strong expression in cardiomyocytes and weaker staining within amyloid deposits. Together, these findings indicate that ECM remodeling, alongside complement and coagulation activation, represents a reproducible feature of cardiac ATTR amyloidosis. Whole-tissue proteomics provides biological insights that extend beyond amyloid typing, with potential implications for biomarker discovery and therapeutic targeting in ATTR-CA.

ObjectiveN-acetylcysteine (NAC) is a clinically available antioxidant with potential applications in trauma-induced hypermetabolic states, including burn injury and crush syndrome. However, its effects on heat-stressed skeletal muscle cells remain incompletely characterized. This study conducted a secondary analysis of a publicly available dataset to quantify NACs protective effects against heat-stress-induced cellular damage. MethodsWe re-analyzed a publicly available dataset (Lu J, 2024, Mendeley Data, doi:10.17632/wffrtcgbnx.1) containing 21 observations across three conditions: Control (n=3), Heat Stress only (HS, n=3), and HS with NAC at five doses (0.5-8.0 mM, n=3 per dose). The primary outcome was the protective ratio [(HS+NAC - HS) / (Control - HS)], where 1.0 indicates complete protection. Statistical analyses included one-way ANOVA, post-hoc t-tests with Bonferroni correction, Cohens d effect sizes, and bootstrap confidence intervals. ResultsHeat stress significantly reduced cell viability by 56.3% (Control: 100.0 {+/-} 12.2 vs HS: 43.7 {+/-} 5.1; t(4)=7.37, p=0.002, Cohens d=6.02). NAC demonstrated a biphasic dose-response with maximal protection at 2.0 mM (66.7 {+/-} 14.4), yielding a protective ratio of 0.409 (95% CI: 0.146-0.675), representing 40.9% protection against heat stress damage. The comparison between HS and HS+NAC (2.0 mM) showed a large effect size (Cohens d = 2.12) but did not reach statistical significance (p = 0.060) due to the small sample size. One-way ANOVA confirmed overall group differences (F(2,18)=32.39, p<0.001, 2=0.783). ConclusionsNAC provides partial protection against heat stress-induced skeletal muscle cell damage at 2.0 mM, with a large effect size suggesting clinical relevance despite limited statistical power. These preliminary findings support further investigation of NAC as an adjunct therapy in trauma-induced hypermetabolic states. All analysis code is provided for reproducibility.

Mitochondrial morphology and function are critical determinants of neuronal function and survival, with disruptions in mitochondrial dynamics often preceding the overt neuronal dysfunction seen in neurodegenerative diseases such as Alzheimers disease, Huntingtons disease and Parkinsons disease. The kynurenine pathway accounts for 95% of dietary tryptophan catabolism and many of the metabolites are neuroactive, including redox-active 3-hydroxykynurenine (3-HK). 3-HK is present under normal physiological conditions in the central nervous system (CNS) and is elevated during inflammation. While supraphysiological levels of 3-HK have been associated with neurotoxicity, the effects of physiological concentrations on neuronal cells, and specifically their mitochondria, remain poorly understood. Here we assessed viability, ATP levels and redox status to determine cellular health and function in neuronal cells exposed to physiological levels of 3-HK, alongside confocal imaging and transcriptomic profiling, finding significant alterations in mitochondrial function and morphology. Interestingly, a biphasic influence of 3-HK on mitochondrial morphology was observed, with an elongated network as well as decreased surface area and volume being observed only at the lowest concentration of 3-HK, reflecting normal physiological levels. At the highest 3-HK concentration tested, reflecting an inflammatory situation, an increased number of mitochondria were present, accompanied by increased activation of caspase-3/7 and enhanced production of mitochondrial superoxide. These results highlight a previously unknown role for 3-HK in regulating mitochondrial function and structure, possibly through altered fission and fusion events, suggesting that subtle changes in kynurenine pathway metabolism may contribute to early mitochondrial dysfunction in neurological disease.

Background & AimsMetabolic disorders such as dyslipidemia, metabolic dysfunction-associated steatotic liver disease (MASLD), and diabetes are promoted by chronic pro-inflammatory and pro-oxidative states. Paraoxonase 1 (PON1), a liver-derived HDL-associated enzyme, plays an important antioxidant role by hydrolyzing oxidized lipids and protecting against oxidative stress- induced damage. Genetic variation in PON1, particularly in promoter and coding regions, modulates enzyme expression and activity, thereby influencing susceptibility to metabolic and cardiovascular diseases. This study investigated the genetic determinants of serum paraoxonase (PONase) activity and their relationship with dysmetabolic phenotypes. MethodsA genome-wide association study was conducted in 922 Portuguese individuals from the PREVADIAB2 cohort. Genetic variants and haplotypes related to PONase activity were analyzed, and associations with dysglycemia and liver fibrosis were evaluated in individuals aged over 55 years. ResultsWe identified two key PON1 variants as determinants of PONase activity: rs2057681 (in strong linkage disequilibrium with the non-synonymous Q192R variant) and rs854572 (located in the promoter region). Analysis of rs854572-rs2057681 haplotypes revealed that specific combinations differentially modulate PONase activity and confer risk or protection for dysglycemia and liver fibrosis, depending on the rs2057681 genotype context. Notably, although PONase activity was strongly associated with PON1 variants, it did not directly correlate with dysmetabolic phenotypes, suggesting that genetic context and haplotype structure, rather than enzyme activity alone, shape disease susceptibility. ConclusionsThese findings highlight the complex genetic architecture of PON1 and its role in metabolic disease risk, supporting the use of PON1 genetic information to uncover predisposition to dysmetabolic conditions. Our results provide insights into the interplay between PON1 genetics, enzyme function, and dysmetabolism, with implications for risk stratification in metabolic liver disease. Lay SummaryPON1 is a liver-derived gene that encodes an enzyme involved in protection against oxidative stress, a key contributor to metabolic liver disease and diabetes. In this study, we found that specific combinations of PON1 genetic variants are associated with abnormalities in blood glucose regulation and with markers of liver fibrosis. These associations were dependent on genetic configuration rather than enzyme activity alone, suggesting that PON1 genetic information may help identify individuals at higher risk of metabolic liver disease.

CaMKII{delta} is the dominant isozyme of Ca2+/calmodulin-dependent protein kinase II in the heart. Under certain pathological conditions, it can be oxidized, causing a constitutive activation that can lead to cardiac failure. We recently showed that, in purified CaMKII{delta} exposed to oxidative conditions, a disulfide link formed between Cys273 and Cys290 causes this autonomous activation. Cys273 has a low pKa that facilitates the oxidation of its thiol to a sulfenic acid at physiological pH. Does this matter in vivo? To answer that question, we created a transgenic mouse with Cys273 mutated to serine (CaMKII{delta}C273S) to prevent disulfide formation. We conducted a detailed assessment of cardiac function at rest and in a dobutamine stress test. We found that the CaMKII{delta} Cys273Ser mutation does not have deleterious effects on cardiac physiology. Then, we assessed whether the mutation would protect the heart from ischemia-reperfusion in the Langendorff model. The CaMKII{delta}C273S mouse had improved cardiac function and decreased infarct size compared to the wild-type mouse. We conclude that blocking disulfide formation at Cys273 protects the heart against ischemia-reperfusion injury. Drugs that specifically target Cys 273 may be therapeutic in human cardiac disease.

Pro-death Bax isoform Bax{Delta}2 forms protein aggregates in Alzheimers neurons, triggering stress granule formation and neuronal cell death. In seeking chemical ligands to prevent Bax{Delta}2 monomer aggregation, we performed in silico screening of FDA-approved drugs using computational docking. This screening identified a group of compounds that bind to the hydrophobic pocket of Bax{Delta}2. Subsequent wet-lab testing revealed that digoxin could block neuronal cell death at nanomolar concentrations (50 to 100 nM). Importantly, digoxins protective role is specific to Bax{Delta}2-induced cell death and is independent of its primary cardio-action on Na/K-ATPase. Further investigation suggests that digoxin does not significantly affect the formation of Bax{Delta}2 aggregates but may instead modulate Bax{Delta}2 protein levels. Although the therapeutic use of digoxin for Alzheimers disease is not feasible due to its narrow therapeutic window and toxicity, these findings open the door for chemical modification of digoxin, or development of similar compounds, to prevent Bax{Delta}2-mediated neuronal cell death in Alzheimers disease.

Multiple acyl-CoA dehydrogenase deficiency (MADD) is a mitochondrial lipid storage myopathy characterized by impaired fatty acid {beta}-oxidation, mitochondrial dysfunction, and progressive neuromuscular and cardiac disease. MADD is most commonly caused by pathogenic variants in electron transfer flavoprotein dehydrogenase (ETFDH), which encodes electron transfer flavoprotein-ubiquinone oxidoreductase (Etf-QO), a critical redox enzyme that transfers electrons from acyl-CoA dehydrogenases to the mitochondrial electron transport chain. Defective Etf-QO activity disrupts electron flow, promotes reactive oxygen species (ROS) production, and impairs cellular energy metabolism, linking abnormal lipid oxidation to oxidative stress-mediated tissue damage. To investigate the role of redox imbalance in MADD pathogenesis, we generated CRISPR/Cas9 knock-in Drosophila melanogaster models carrying patient-relevant Etf-QO missense mutations (L127R, S296C, and L399F; corresponding to human L138R, S307C, and L409F) within conserved FAD- and ubiquinone-binding domains. Mutant flies developed progressive locomotor impairment, reduced muscle performance, and marked lipid droplet accumulation in skeletal muscle, cardiac tissue, and fat bodies, indicating systemic defects in mitochondrial lipid utilization. Cardiac analyses demonstrated reduced fractional shortening, prolonged heart period, and increased arrhythmia index, consistent with metabolic cardiomyopathy associated with mitochondrial oxidative stress. In vivo respirometry revealed significantly decreased oxygen consumption, reflecting impaired oxidative phosphorylation. At the molecular level, mutant flies exhibited elevated ROS levels and ATP depletion, accompanied by increased expression of AMPK, PGC-1, and Tfam, suggesting activation of energy stress signaling and compensatory mitochondrial biogenesis. Importantly, endurance exercise significantly improved locomotor and cardiac function while reducing lipid accumulation and oxidative stress. Together, these findings establish a redox-centered in vivo model of MADD and identify oxidative stress as a major driver of disease pathology and a potential therapeutic target.

Objective Fatty Acid esters of Hydroxy-Fatty Acids (FAHFAs) are anti-diabetic and anti-inflammatory lipokines produced mainly by adipose tissue (AT). As exercise training enhances FAHFA levels, we investigated the impact of acute exercise (AE) and exercise-mimicking conditions on circulating and adipocyte FAHFA levels. Methods Clinical trial (NCT05572905) in 60 women, grouped by BMI (lean vs. obese) and age (young vs. older), was combined with in vitro experiments on human adipocytes. Following baseline characterization (body composition, VO2max, insulin sensitivity, AT/plasma FAHFAs), women underwent a cross-over AE and control interventions with repeated blood sampling for FAHFA analysis. Results In AT, lean and older women exhibited higher FAHFA levels than obese and young women, respectively; older women also showed a shift toward higher levels of 13/12-carbon-branched FAHFAs. Circulating FAHFA levels were similar across all groups and were not positively associated with insulin sensitivity, VO2max or FAHFA levels in AT. Although AE increased circulating free fatty acids (FFA), plasma FAHFAs dropped in response to both AE and control interventions. In adipocytes, FAHFAs were unaffected by glucocorticoids but increased in response to lipolysis together with gene expression related to FFA oxidation (FAO). Nevertheless, blocking mitochondrial FAO partially mimicked the lipolytic effect, while peroxisomal inhibition synergistically boosted FAHFA lipolysis-driven production despite having no effect alone. Conclusions While adiposity and aging modulate FAHFA levels in AT, circulating levels remain stable and unaffected by AE, challenging subcutaneous AT as their primary systemic source. In vitro, FAHFA synthesis is driven by high FFA availability but limited by competing peroxisomal FAO.

Chronic exposure to ultraviolet (UV) radiation, known as photoaging, accelerates skin aging by inducing molecular, histological, and functional changes. This study established a mouse model using SKH-1 hairless mice to investigate chronic UV-induced photoaging over eight weeks. SKH-1 hairless mice were exposed to a combination of UVA and UVB, and the progression of skin damage was monitored through physical, histological, and molecular parameters, with a focus on erythema, transepidermal water loss, and collagen and hyaluronan (HA) metabolism. Significant reductions in HA content and alterations in DNA repair markers, such as {gamma}H2AX, were observed, highlighting the impact of chronic UV exposure on skin structure and function. Reactive adipogenesis and increased epidermal thickness were noted, reflecting adaptive responses to UV-induced damage. By investigating these parameters over the evaluation period, we provide a comprehensive time-course analysis of the progressive impact of UV-induced photoaging, offering insights into the underlying mechanisms and potential therapeutic targets to prevent or delay photoaging.

BackgroundFerroptosis has emerged as a promising therapeutic target in IRI. However, it remains largely unclear how and when this iron-dependent regulated cell death manifests during IRI. Therefore, we explored malondialdehyde (MDA), a byproduct of lipid peroxidation, and glutathione peroxidase 4 (GPX4), as a marker of redox capacity, in multiple IRI models. With this explorative study, we aimed to uncover MDA dynamics in renal and hepatic IRI, which could provide valuable insights for future internal studies. MethodsHistorical plasma and tissue samples from rat and porcine models of renal and hepatic IRI were selected based on varying conditions of ischemic injury, reperfusion and perfusion. MDA was measured using a colorimetric assay with N-methyl-2-phenylindole, methanol, acetonitrile and hydrochloric acid and quantified at 595 nm. GPX4 protein concentrations were investigated using standard western blotting. ResultsIn rat clamping models, plasma MDA concentrations revealed no difference between control and IRI settings. However, an increasing trend could be observed in tissue samples after IRI. Similarly, a decrease in tissue GPX4 concentrations was observed after IRI. In porcine studies, MDA concentrations were increased during reperfusion of kidneys exposed to prolonged warm ischemia and livers exposed to short periods of cold ischemia. Dynamic preservation could attenuate MDA concentrations. ConclusionWe found that MDA and GPX4 are affected within the first hours after reperfusion, stressing the need for early sampling in studies focusing on characterizing ferroptosis. Moreover, MDA dynamics during organ perfusion revealed an increased vulnerability of ischemic organs to lipid peroxidation and a potential protective effect of dynamic preservation. These preliminary results should be confirmed in studies focusing on ferroptosis characterization, as notable observations regarding sample age and storage conditions and experimental design limit the validity of this study.

Catechinopyranocyanidins (Cpcs) which consist of diastereomers A and B are pigments derived from adzuki beans and are compounds in which the catechin and cyanidin skeletons are condensed to a pyrano ring. While catechins and anthocyanidins possess high antioxidant capacity, the physiological functions of Cpcs remains unclear. In this study, the antioxidant capacity of Cpcs was evaluated by in vitro antioxidant assays and by assessing their cytoprotective activity against oxidative stress in normal human dermal fibroblasts (NHDFs). Antioxidant capacity based on the hydrogen atom transfer (HAT) mechanism, as assessed by the ORAC assay revealed that Cpcs exhibit 14.1 mol TE/mol (Trolox equivalent antioxidant capacity: TEAC). Meanwhile, capacity based on the single electron transfer (SET) mechanism, as assessed by the DPPH, ABTS and CUPRAC assays revealed, they exhibit 2.1-3.6 mol TE/mol. Since TEAC value of Cpcs demonstrated by the HAT based mechanism higher than its SET based oxidative capacity suggesting that the antioxidant capacity of Cpcs is driven by the HAT mechanism. In cell culture experiments, Cpcs ameliorate cell toxicity in rotenone-induced injury model, suggesting to cytoprotective activity against mitochondrial dysfunction-dependent apoptosis. These results reveal novel physiological functions of Cpcs which may serve as a design guideline for elucidating in vivo dynamics based on antioxidant mechanisms.