Antioxidants

Staphylococcus aureus encounters massive oxidative stress during infection. To counter this, the bacterium developed robust antioxidative defense mechanism. Glutathione peroxidases (Gpx) are well characterized antioxidative enzymes in eukaryotes; however, their bacterial counterparts remain poorly explored. S. aureus possesses two putative Gpx genes but lacks GSH biosynthetic machinery and glutathione reductase required for canonical Gpx function, suggesting alternate electron donor system(s) may be involved. This study aimed to elucidate structure-based biochemical characterization of one of the S. aureus glutathione peroxidases homologs (SaGpx, Uniprot Id: Q2FYZ0) and identify its plausible electron donor system. Herein, we cloned, purified and determined the high-resolution crystal structure of SaGpx (1.5 [A] resolution) using X-ray diffraction crystallography. In vitro biochemical characterization of the highly conserved active site amino acid point mutants, as well as their structural disposition suggests their precise roles in the enzymes catalysis. The crystal structure of SaGpx revealed that the enzyme adopts a canonical glutathione peroxidase fold with conserved catalytic tetrad composed of C36, Q70, W124 and N125. Also, SaGpx shows similarity with mammalian Gpx4, which was previously shown to exert phospholipid hydroperoxide peroxidase activity. Furthermore, biochemical assays suggest that SaGpx utilizes Staphylococcal thioredoxin1 as its cognate electron donor. The catalytic mechanism follows an atypical 2-cysteine peroxiredoxin-like pathway involving the formation of a sulfenic acid intermediate, followed by an intramolecular disulfide bond subsequently resolved by thioredoxin. This work provides the first structure-based biochemical characterization of a bacterial glutathione peroxidase homolog, establishing the novel structural insights of SaGpx as a noncanonical thioredoxin-dependent glutathione peroxidase.

Light is essential for photosynthetic organisms, but excess light can generate toxic levels of reactive oxygen species (ROS). To neutralize these ROS, plants and algae produce a variety of antioxidants like carotenoids, tocopherols, and glutathione. However, the role of alternative ROS scavengers, such as ovothiols, has not been studied in the context of oxidative stress in photosynthetic organisms. Here, we report that many algal groups have the potential for the biosynthesis of ovothiols, a group of thiohistidines. We discovered that the model green microalga Chlamydomonas reinhardtii produces millimolar concentrations of ovothiol A, whose biosynthesis is mediated by the ovothiol synthase OVOA1. Using CRISPR-generated ovoa1 knockout mutants, we found that ovothiol production is essential for resistance and acclimation to singlet oxygen, a prominent ROS in photosynthetic organisms. Finally, we demonstrated that OVOA1 expression is activated by singlet oxygen and light signaling pathways in which we identified the major regulatory factors. Overall, our results show that ovothiol A is a major, previously overlooked antioxidant in Chlamydomonas. This work broadens our understanding of cellular mechanisms that combat the damaging effects of oxidative stress. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/702910v2_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@cddb9corg.highwire.dtl.DTLVardef@10d0a43org.highwire.dtl.DTLVardef@11cc087org.highwire.dtl.DTLVardef@a40cc5_HPS_FORMAT_FIGEXP M_FIG C_FIG

Glutathione peroxidases (GPXs) are widely recognized as key antioxidants that mitigate oxidative stress by detoxifying reactive oxygen species (ROS). However, GPXs are largely uncharacterized in citrus. Here, we demonstrated that Citrus sinensis contains four GPX proteins (CsGPX1-4). Unexpectedly, overexpression of CsGPX4, a homolog of AtGPX8 in Arabidopsis, in citrus resulted in typical oxidative stress phenotypes including severe growth inhibition, chlorosis, and elevated intracellular ROS accumulation. Transmission electron microscopy (TEM) analysis further revealed stress responses at cellular level. Whole genome shot gun sequencing analysis showed that T-DNA insertion occurs in the UTR of SWEET2 gene, which is unlikely to be responsible for the oxidative stress phenotypes. Immunoblotting revealed that CsGPX4 accumulates as a truncated protein in citrus, in contrast to the full-length version expressed in Nicotiana benthamiana. MALDI-TOF assays further confirmed the truncation of CsGPX4 in the transgenic line with the predicted cleavage site between L115-K117. This truncation was associated with altered subcellular localization, shifting from cytoplasmic and nuclear distribution in N. benthamiana to membrane association in citrus. Proteomic profiling further indicated extensive reprogramming of pathways involved in detoxification, cytoskeletal stability, hormone signaling, and cell wall modification. Our data suggests that de facto overexpression of truncated CsGPX4 may have dominant-negative effects on proteins interacting with CsGPX4, thus interfering with their normal functions. In conclusion, our study demonstrates CsGPX4 as a critical regulator of redox homeostasis and ROS homeostasis in citrus and reveals selective truncation of CsGPX4 as a unique proteolytic or regulatory strategies in such processes.

Reactive oxygen species (ROS) play a dual role in cellular homeostasis, but excessive levels of ROS lead to oxidative stress, accelerating skin aging. Environmental stressors like UV radiation induce ROS overproduction, overwhelming endogenous antioxidant defenses and causing cellular damage. While the skin possesses an intrinsic antioxidant network that provides moderate protection, excessive oxidative stress can trigger inflammatory responses, thereby necessitating exogenous antioxidant intervention. Microbe-derived antioxidants (MA), produced via probiotic fermentation of sea buckthorn and chestnut rose, have shown promise in mitigating ROS-induced damage. In this study, we evaluated two MA formulations, MA1 and MA2, for their ability to scavenge free radicals and alleviate hydrogen peroxide (H2O2)-induced oxidative stress in human dermal fibroblasts (HDF) and dermal papilla cells (HDP). Both formulations displayed dose-dependent DPPH radical scavenging activity and enhanced cell viability at low concentrations. Under H2O2-induced oxidative stress, MA1 and MA2 effectively restored intracellular ROS to baseline levels, demonstrating significant cytoprotective effects. UHPLC-MS/MS profiling identified 12 compounds shared by both formulations, and Gene Ontology Biological Process enrichment analysis revealed that their associated target genes were significantly enriched in antioxidant-related pathways. Five compounds--adenosine, citric acid, 5-hydroxymethylfurfural, myricetin, and phenylalanine--emerged as key contributors to the observed antioxidative effects. Together, these findings highlight the potential of fermented microbial antioxidants to re-establish redox homeostasis in human skin cells and support their further development as therapeutic or cosmetic interventions targeting oxidative stress and skin aging. Given the heightened oxidative sensitivity of aged fibroblasts, MAs ability to alleviate ROS may offer novel therapeutic strategies against skin aging and related pathologies.

Exposure to cigarette smoke is one of the major risk factors for developing various diseases such as chronic obstructive pulmonary disease (COPD), cardiovascular disorders, and cancer mediated via cellular oxidative stress and organelle dysfunction. To this end, the current study investigated how cigarette smoke extract (CSE) affects vacuole structure and function in Saccharomyces cerevisiae, as vacuole plays a crucial role in handling oxidative stress-induced misfolded proteins. Our results showed that CSE exposure causes transient vacuolar fragmentation up to 1 h to increase its surface area to facilitate microautophagy in clearing CSE-mediated misfolded protein and promoting cell survival. However, excessive fragmentation or vacuolar fusion sensitizes cells towards CSE-mediated cellular toxicity. Towards understanding the underlying mechanism, the current study demonstrated the involvement of PI3P and PI (3,5) P2-mediated signaling and phospholipase-driven remodeling of lipid moieties. Moreover, the current study also showed the importance of mitochondrial activity in CSE-mediated vacuolar fragmentation. Prolonged exposure to CSE impairs mitochondrial function and thus disrupts fragmentation, the adaptive survival strategy against CS. It results in proteostasis collapse, which is a characteristic shared by many inflammatory and degenerative disorders. Taken together, the current study reveals a previously unrecognized cellular protection mechanism induced by cigarette smoke and highlights potential therapeutic targets for mitigating CS-mediated diseases

BackgroundChronic inflammation and oxidative stress are central drivers of cardiovascular disease progression and remain incompletely addressed by existing pharmacological strategies. Traditional medicinal plants provide a valuable source of multi-target bioactive compounds that may modulate these interconnected pathways. Rauwolfia serpentina, a classical antihypertensive plant in Ayurveda, has been historically valued for cardiovascular indications. Yet, its antioxidant and anti-inflammatory actions beyond blood pressure regulation remain insufficiently characterised in immune-driven inflammatory models. MethodsRoot extracts of R. serpentina prepared using hot and cold ethanol and water were evaluated for antioxidant capacity using DPPH radical scavenging and phosphomolybdenum assays, along with phenolic, flavonoid, and terpenoid quantification. Protective effects against lipid peroxidation were assessed in rat liver and heart homogenates. Anti-inflammatory activity was examined in THP-1 human monocytic cells exposed to lipopolysaccharide (LPS), arachidonic acid (AA), and oxidative stress. Cytokine secretion and gene expression of TNF-, MCP-1, IL-6, and IL-8 were measured by ELISA and qRT-PCR. Intracellular reactive oxygen species and catalase activity were quantified to assess oxidative regulation. LC-MS-based metabolomic profiling was performed to characterise chemical diversity. The principal alkaloid, reserpine, was evaluated separately, and molecular docking was performed to examine its interaction with IKK. ResultsEthanolic extracts of R. serpentinas root, particularly the cold ethanolic fraction, showed superior antioxidant capacity, higher phenolic and flavonoid content, and potent inhibition of lipid peroxidation. These extracts markedly suppressed LPS-induced cytokine release and gene expression in THP-1 cells, with pronounced effects on MCP-1 and IL-6. Oxidative stress induced by arachidonic acid was attenuated through reduced intracellular ROS and preservation of catalase activity. Reserpine reproduced key features of the extract response, demonstrating strong suppression of IL-6 and MCP-1 at both transcriptional and secretory levels. Docking analysis indicated stable binding of reserpine within the IKK catalytic pocket, supporting a plausible mechanism for modulation of the NF-{kappa}B pathway. ConclusionR. serpentina root extracts exhibit coordinated antioxidant and anti-inflammatory activity in immune cell models relevant to cardiovascular inflammation. These effects are extraction-dependent and are partially mediated by reserpine through modulation of oxidative stress and inflammatory signalling pathways. The findings support the translational relevance of R. serpentina as a traditional medicine with mechanistic activity extending beyond antihypertensive action.

Age-related macular degeneration (AMD) is a leading cause of irreversible vision loss in ageing populations, with oxidative stress recognised as a key pathogenic driver. The dietary antioxidant and cytoprotectant, L-ergothioneine (ET), is avidly accumulated in many tissues, especially the eye. However its relationship to AMD has not been investigated. Here, we examined ETs distribution in ocular tissue and assessed circulating and intraocular ET levels in patients with neovascular AMD. Compared with ocularly-normal age-matched individuals, AMD patients exhibited significantly lower serum ET; elevated levels of ET metabolites, hercynine and ETSO, which may be generated by oxidative stress; and elevated levels of serum allantoin, a product of oxidative damage to urate in humans. Levels of ET in aqueous humour in AMD patients were marginally lower than cataractous patients who are already known to have significantly lower ET levels than healthy eyes. High ET levels were seen in human ocular tissues concentrating in regions vulnerable to oxidative injury, including the lens, retina, retinal pigment epithelium, and choroid, supporting a physiological protective role of ET in the eye. These findings identify the strong association between low ET levels and AMD, warranting further studies to determine whether ET supplementation can modify AMD risk or progression.

Photosynthetic electron transport is mediated by several protein supercomplexes that are spatially arranged in the thylakoid membranes of chloroplasts. The chloroplast NADH dehydrogenase-like (NDH) complex is part of the photosynthetic alternative electron transport (AET) chain, which reduces the plastoquinone (PQ) pool using reduced ferredoxin as a substrate. This NDH complex is associated with photosystem I (PSI) and mediates a portion of AET in stroma lamellae, whereas photosystem II (PSII) is concentrated in grana stacks. This study presents the findings regarding post-illumination chlorophyll fluorescence increase (PIFI), a protein crucial for regulating AET via the NDH pathway. A marked increase in NDH activity and a reduction in the PQ pool in the dark were observed in PIFI-deficient mutant strains (g-pifi) generated by genome editing. Blue native PAGE analysis indicated that PIFI was associated with the NDH-PSI supercomplex in the wild type, and the NDH complex was dissociated from PSI in the g-pifi mutants. Additionally, the g-pifi mutants exhibited a decrease in the maximum quantum yield of PSII (Fv/Fm). Notably, Fv/Fm was restored in a double mutant harboring both g-pifi and NDH-deficient pnsl1 mutations, demonstrating that deregulated NDH activity in g-pifi causes downregulation of PSII efficiency. However, the lower Fv/Fm was not observed in a mutant lacking thioredoxin m4 (trxm4), which showed deregulated NDH activity but maintained the NDH-PSI supercomplex. These data suggest that PIFI stabilizes the NDH-PSI supercomplex and maintains the spatial localization of PQ reduction via AET in thylakoid membranes, which is essential for the proper functioning of PSII.

Zinc is essential for life, and its regulation is tightly controlled by numerous transporters. As we age, our micronutrient levels, intake, and absorption change. Additionally, senescent cells increase with age and can contribute to the progression of age-related diseases. The study of Zn homeostasis in senescent intestinal cells is a relatively unexplored area that we aimed to investigate. Using two models to induce senescence in intestinal epithelial cells--etoposide treatment and {gamma}-irradiation--we observed that Zn levels increased in the cells, likely due to the upregulation of Zn transporters ZIP4 and ZnT7. This upregulated Zn seems to accumulate in the Golgi apparatus, and when Zn accumulation is blocked through chelation, a rescue effect occurs, marked by a decrease in senescence markers. This research emphasizes the role of Zn in senescent cells and its possible involvement in the development of senescence and the disrupted Zn homeostasis seen with aging.

BackgroundDiabetes-associated neurodegeneration is amplified by methylglyoxal (MGO)-driven dicarbonyl stress linking hyperglycemia to neuronal insulin resistance and maladaptive neuroinflammation. We tested the neuroprotective activity of MNP-021, a non-electrophilic TRPA1 modulator, in neurons and glial cells in vitro. MethodsSH-SY5Y neurons were pretreated with MNP-021 and challenged with MGO, then profiled by high-content imaging, RNA-seq, Seahorse OCR/ECAR, glycolytic stress assays and AKT/ERK/CREB immunoblotting {+/-} insulin. In parallel, HMC3 glial cells were treated with MNP-021, exposed to LPS/TNF- or A{beta}(25-35) and tested for viability and inflammatory markers by ELISA and qRT-PCR. ResultsMGO increased nucleus-to-cytoplasm area ratio by 49% and dysregulated glucose handling, increasing 2-NBDG uptake by [~]25%, with GLUT1/GLUT4 membrane redistribution; MNP-021 normalized morphology, uptake, and transporter localization without cytotoxicity up to 10 {micro}M. RNA-seq identified 754 MGO-deregulated genes, including ISR/metabolic nodes (GCK, SESN2, PHGDH/PSAT1, PCK2); MNP-021 buffered stress-induced transcription with limited baseline effects, remodeled mitochondrial redox readouts consistent with controlled ROS signaling, while improving mitochondrial content/architecture and blunting stress-evoked compensatory glycolysis. MNP-021 restored pro-survival signaling (pAKT/pERK and nuclear pCREB), including insulin responsiveness during MGO exposure. MNP-021 reduced IL-6/TNF- release while increasing IL-10 and ARG1 ([~]1.9-fold vs LPS/TNF-) in HMC3 glial cells, shifting them toward a pro-resolving IL-10/ARG1 program with reduced A{beta}(25-35)-evoked cytokine release with GLP-1 remaining very low ([≤]10 pg/mL) and not significantly increased in this system. ConclusionsMNP-021 coordinates transcriptomic restraint, transporter-level glucose handling, mitochondrial resilience, and pro-survival/pro-resolving signaling across neuron-microglia compartments, supporting TRPA1-tuned small-molecule modulation as a candidate strategy against dicarbonyl-linked neuro-metabolic stress.

Mitochondria are essential for metabolic homeostasis and neuronal function, extending beyond ATP production to roles in cell signaling, inflammation, and stress responses. Mitochondrial dysfunction, marked by abnormal morphology, ATP deficiency, and oxidative stress, is a key feature of aging-related diseases and neurodegenerative disorders like Parkinsons. Given the importance of mitochondrial homeostasis to brain function, this study aimed to determine the possible vitamin D (VD3) effects on mitochondrial susceptibility to Ca2+-induced mitochondrial permeability transition pore (mPTP), bioenergetics in brain mitochondria, and redox balance. We demonstrated that VD3 protects isolated brain mitochondria. Male rats were divided into control and VD3-treated groups. Brain mitochondria were isolated for assessments of Ca2+-induced mitochondrial swelling secondary to MPTP opening, oxygen consumption (states 3 - ADP-stimulated and state 4 - in the presence of oligomycin), and the respiratory control ratio (RCR). Oxidative stress parameters (nitrite and lipid peroxidation), superoxide dismutase (SOD) activity, and reduced glutathione (GSH) levels were also evaluated. The results revealed that VD3 treatment blocked Ca2+-induced mitochondrial swelling secondary to MPTP opening. Additionally, VD3 improved mitochondrial RCR compared to controls, in the presence of complex I (malate/glutamate) and complex II (succinate) substrates, reduced mitochondrial succinate-driven H2O2 release, and enhanced SOD activity and GSH levels. These changes occurred in parallel with decreased nitrite and TBARS formation. These results suggest that vitamin D{square} confers mitochondrial neuroprotection, emphasizing its prospective role in maintaining neuronal homeostasis and mitigating neurodegenerative processes.

Synthetic 6-Br-Q0C10 has been shown to exhibit a partial electron transfer activity of native coenzyme Q in the isolated mitochondria. It reduces energy coupling efficiency by approximately 30%, suggesting that it may be useful in modulating cell growth in tissue culture. Whether or not it behaves in the same way in the whole cells, or animal, however, has not yet been fully examined. Recently we have investigated the effect of 6-Br-Q0C10 across multiple cell lines using three detection methods. Treatment with 6-Br-Q0C10 reduces cell proliferation in all cell lines tested, with different effectiveness. Obesity-related cell lines were the most susceptible, and a pronounced inhibitory effect was also observed in cancer cell lines. These results strengthen the idea of using 6-Br-Q0C10 to manage obesity or to retard the growth of rate cancer cells and thus prolonging life.

Diabetes Mellitus (DM) is a rapidly increasing disease around the world. It is known that DM is associated with numerous complications which affect life quality by its debilitating nature. DM is associated with cognitive impairment and neurodegeneration, partly driven by neuroinflammation and disrupted neuronal signalling. Incretin-based treatments have recently been suggested to exert potential effects on the central nervous system in diabetic patients. However, the triple agonist of GIP/GLP-1/GCG Retatrutides effects on cognition under diabetic conditions remain unexplored. This study aims to reveal whether impaired cognitive performance, such as learning and memory, is ameliorated by Retatrutide treatment in diabetic rats, together with associated metabolic, inflammatory and histological changes. Male Sprague-Dawley rats were allocated to four groups: control (C), streptozotocin-induced diabetic (STZ), streptozotocin-induced diabetic rats treated with Retatrutide (STZR), and sham rats treated with Retatrutide alone (R). DM was induced by streptozotocin injections. Spatial learning and memory were assessed using the Morris Water Maze and Passive Avoidance tests. Metabolic parameters were monitored, while neuroinflammatory markers (IL-1{beta}, TNF-), neurotrophic-related gene expression (BDNF, CREB, AKT), Tau protein levels, and histopathological changes in the cortex and hippocampus were evaluated using molecular, biochemical, and histological analyses. Streptozotocin-induced diabetes resulted in persistent hyperglycaemia, total body weight loss, impaired learning and memory. Retatrutide treatment reduced blood glucose levels without achieving a full euglycaemia or preventing weight loss. Behavioural tests showed that Retatrutide treatment preserved spatial learning and short-term memory compared to untreated animals. These effects were accompanied by attenuation of neuroinflammatory responses, particularly reduced TNF- levels, trends toward preserved neurotrophic-related transcriptional profiles, and partial maintenance of cortical and hippocampal structural integrity. Retatrutide alone did not enhance cognitive performance beyond control levels. These findings support the hypothesis that triple agonists may exert beneficial effects on cognitive performance under diabetic conditions. Retatrutide alleviates DM-associated cognitive impairment in streptozotocin-induced diabetic rats and is associated with reduced neural inflammatory burden and protected neuroanatomical structure. The observed cognitive benefits appear to extend beyond metabolic regulation alone. Further studies in models more closely reflecting type 2 diabetes are warranted to clarify the underlying mechanisms and translational relevance.

C4 photosynthesis is a CO2-concentration mechanism that separates CO2 fixation between two cell types, thereby reducing photorespiration and making C4 plants more efficient than their C3 counterparts. While the C4 cycle has evolved multiple times across different genera, this study evaluates very closely related C3 and C4 species within the genus Flaveria. Apart from their carbon metabolism, C4 plants also possess adaptations in their mineral nutrition. One key nutrient which is also directly involved in photosynthesis is phosphorus. It is absorbed by the plant in the form of inorganic phosphate and is an essential component of DNA, ATP, lipids, and carbohydrates. In the Flaveria C4 species, but not in the C3 species, phosphate limitation was shown to affect the dark reactions of photosynthesis. This study investigates how phosphate deficiency impacts the light reactions in C3 and C4 Flaveria plants. We observed a differential response in the functionality of photosynthetic energy conversion between the two species. When exposed to a limited phosphate supply, the C3 species reduced its linear electron transport rate while dissipating excess energy through high-energy quenching, which was regulated by a higher pH gradient across the thylakoid membrane. In contrast, the C4 species did not regulate its photosynthetic light reaction under phosphate limitation. Instead, it exhibited increased stress levels, evidenced by a stronger biomass reduction and the induction of stress markers in the leaves. Additionally, this study uncovered an acceleration in NPQ relaxation during phosphate limitation, regardless of the photosynthesis type. HighlightPhosphate deficiency reduced linear electron transport rates and induced dissipation of excess energy through non-photochemical quenching in the C3 Flaveria species, while in the C4 species, despite elevated stress levels, the photosynthetic light reactions were unaffected.

Cadmium is a very toxic heavy metal. We studied Cd-treated barley plants with especial focus on rare atypical plants with signs of chlorosis. Cd treatment decreased the maximal photochemical activities of both photosystems while the activity of photosystem I decreased more than activity of photosystem II. In photosystem II, Cd treatment inhibited non-photochemical quenching that increased portion of unquenched "closed" complexes of photosystem II. The latter effect increased balance of limitations between the acceptor side of photosystem II (qC) and the donor side of photosystem I (Y(ND)) and raised the ratio qC/Y(ND). All these effects were enhanced in the atypical more damaged plants. Cd treatment reduced K content in the first leaves; in atypical plants, K content decreased even more. Cd treatment changed a pattern of stomatal conductance possibly by means of reducing K content in leaves. The untreated barley plants kept different stomatal conductance at adaxial and abaxial sides of leaves and fulfilled a complicated diurnal dynamics with large ups and downs of stomatal conductance. The typical Cd-treated plants were less flexible and demonstrated medium values. Stomatal conductance in the untreated plants were higher or lower than in the typical Cd-treated plants depending on a particular time; average daytime stomatal conductance was equal in both variants. At 10.00, stomatal conductance in the atypical Cd-treated plants was smaller than in the typical ones. Levels of 13 chloroplast mRNAs remained unchanged, while psbD decreased in both types of Cd-treated plants. HighlightsO_LISeveral Cd effects were enhanced in more damaged (atypical) chlorotic plants C_LIO_LICd treatment decreased activity of photosystem I and non-photochemical quenching C_LIO_LIRatio of limitations between photosystems II and I [qC/Y(ND)] was rather constant C_LIO_LICd treatment reduced K content in the first leaves C_LIO_LICd treatment changed pattern of stomatal conductance C_LI

BackgroundCarnitine plays an obligatory role in energetics owing to its role in the translocation of long-chain fatty acids into the mitochondrion for oxidation. Here, we determined the metabolic and behavioral consequences of systemic carnitine deficiency (SCD) in mice. MethodsFemale C57BL/6J mice were randomized to receive normal drinking water (control, n = 8) or drinking water supplemented with mildronate 4g.L-1 (mildronate, n = 8) for 21 days. Body composition was assessed at baseline and post treatment. Metabolic and behavioral phenotyping was performed continuously over 72 hours following 14 days of control or mildronate treatment. Stable isotope were used to assess whole-body substrate oxidation. Carnitine subfractions were quantified in skeletal muscle and liver, as was mitochondrial respiratory function. Liver and muscle samples also underwent proteomic analysis. ResultsMildronate treatment depleted total carnitine in muscle and liver by [~]97% (P < 0.001) and [~]90% (P < 0.001), respectively. Carnitine depletion was accompanied by lower total energy expenditure (P = 0.01), attributable to lower voluntary wheel running (P = 0.01). Oxidation rates of palmitate (P < 0.01) but not octanoate were lower whereas rates of glucose oxidation were greater in carnitine depleted mice (P < 0.01). Mitochondrial respiratory capacity was unaltered by carnitine deficiency. Carnitine deficiency remodeled muscle and liver proteomes to support lipid oxidation and energy production. SummaryIn mice, carnitine deficiency is characterized by decreased long-chain fatty acid oxidation despite preserved mitochondrial respiratory capacity. Carnitine deficiency resulted in lower voluntary exercise and a concomitant reduction in energy expenditure.

Parkinsons disease (PD) is the second most progressive degenerative disorder of the brain due to dopaminergic (DA) neuron degenerations and alpha-synuclein (-Syn) accumulations. At present, the disease has no effective treatment. Therefore, the current study objective is to identify a novel anti-PD formula (Zhi-Shi-Huang-Wu Formula, F-2) computed at 8:4:2:1 ratio from HSP 70 promoter activators Valeriana jatamansi (V), Acori talarinowii (A), Scutellaria baicalensis (S), Fructus Schisandrae (F). Traditionally, V is used to cure memory impairments, A treats mental disorders, and chronic mild stress, S for neuroprotection, and F showed multiple therapeutic actions to treat insomnia. This study investigated the neuroprotective potential of the V, A, S, F, formula F-2 and its underlying molecular mechanisms in transgenic Caenorhabditis elegans models. A, S, F, and F-2 successfully restored 6-hydroxydopamine intoxicated DA neuron degenerations, reduced food-sensing behavior disabilities, and attenuated -Syn aggregations. Moreover, activates the lipid deposition and proteasome expressions to confirm -Syn degradations at the cellular level. Reactive oxygen species (ROS) cause oxidative stress, and A, S, F, and F-2 repressed ROS and raised SOD-3 expressions. Overall, these data indicate that V, A, S, F combined into F-2 (22.3%) are more effective against PD progression-like symptom than individual drugs V (0.7%), A (11.4%), S (9.6%), and F (12.6%). These improved neuroprotective actions of F-2 possibly due to following the antioxidative pathway. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=144 SRC="FIGDIR/small/709540v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@1a6f1f7org.highwire.dtl.DTLVardef@157a270org.highwire.dtl.DTLVardef@69a238org.highwire.dtl.DTLVardef@1194b5e_HPS_FORMAT_FIGEXP M_FIG C_FIG

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.

Staphylococcus aureus (S. aureus) is a clinically relevant pathogen capable of adapting its membrane composition in response to environmental stress. In this adaptive process, bacterial carotenoids play a crucial role. Although staphyloxanthin (STX) is the main carotenoid produced by the bacterium, S. aureus also synthesizes other pigmented intermediates that play an unknown role in regulating membrane biophysical properties. In this study, we purified 4,4-diaponeurosporenoic acid (4,4'-DNPA) from S. aureus carotenoid extracts and evaluated its effect on the thermotropic and biophysical properties of representative membrane models. The highly rigid triterpenoid 4,4'-DNPA is one of the last precursors in the biosynthesis of STX and is found in high concentrations in the stationary phase of S. aureus. Phase transition temperatures were determined using infrared spectroscopy, while interfacial hydration and hydrophobic core dynamics were investigated using fluorescence spectroscopy through Laurdan generalized polarization and DPH anisotropy. The results show that 4,4'-DNPA increases the main phase transition temperature of lipid bilayers in a concentration-dependent manner. This is in contrast to STX that decreases the transition temperature. This difference is consistent with the additional fatty acid present in STX that changes its effect on the phase behavior. Furthermore, 4,4'-DNPA reduced the interfacial hydration levels and restricted hydrophobic-core dynamics at higher concentrations, consistent with increased molecular order and stability. 4,4'-DNPA therefore complements STX in increasing membrane order and lipid packing. These findings support the notion that the production of bacterial carotenoids functions as a biophysical regulatory mechanism of lipid packing in S. aureus membranes.

This study investigates the therapeutic potential of secretomes derived from Adipose-derived Mesenchymal Stem Cells (ADMSC-CM) and Limbal-derived Mesenchymal Stem Cells (LMSC-CM) against oxidative stress-induced damage in Retinal Pigment Epithelium (RPE-1) cells. RPE dysfunction, often triggered by oxidative stress, is a hallmark of various retinal degenerations. Here, we induced RPE-1 injury using H2O2 and evaluated the restorative effects of both MSC-conditioned media (CM). Our results demonstrated that both ADMSC-CM and LMSC-CM significantly enhanced cell viability and successfully reversed H2O2-induced G2/M phase cell cycle arrest. While oxidative stress triggered a pro-inflammatory response characterized by elevated IL-1{beta}, IL-6, and IL-10 expression, MSC-CM treatment, particularly ADMSC-CM, effectively modulated these levels and suppressed the p38 MAPK signaling pathway. Furthermore, MSC-CM reduced the Bax/Bcl-2 ratio, indicating an anti-apoptotic effect, and appeared to stabilize autophagic flux. To investigate the impact of oxidative-stress induced alterations in retinal pigment epithelial cells on angiogenesis, the effects of RPE-derived secreted factors on endothelial cell function were evaluated. Crucially, in terms of safety and secondary complications, neither secretome exhibited pro-angiogenic tendencies; instead, they significantly inhibited HUVEC migration and invasion compared to the H2O2 damaged group. These findings suggest that both ADMSC and LMSC secretomes provide a potent multi-targeted therapeutic effect, making them promising candidates for cell-free therapies in retinal diseases.