Search Results (613)

Reactive oxygen species (ROS) exert dual biological functions in plants. Though they form toxic byproducts of aerobic metabolism, ROS also serve as indispensable secondary messengers that orchestrate stress acclimation programs. For decades, plant physiologists operated under a pervasive assumption that constitutive and non-compartmentalized upregulation of antioxidant capacity would universally enhance abiotic stress tolerance. This long-standing dogma has now been thoroughly overturned. A growing body of evidence shows that sustained, global high antioxidant activity often impairs adaptation rather than helping it. In this review, we replace the simplistic “more antioxidants equal better tolerance” framework with a dynamic model of cellular redox homeostasis. We dissect three interconnected mechanisms though which unrestrained ROS scavenging generates deleterious phenotypic outcomes. First, indiscriminate clearance blunts transient ROS pulses and propagating ROS waves, the core signaling events acquired to trigger systemic acquired acclimation (SAA). Second, continuous antioxidant biosynthesis drains finite carbon skeletons, NADPH, and ATP pools, exacerbating evolutionary growth-defense resource trade-offs. Third, non-specific bulk ROS scavenging erases compartment-specific organellar retrograde signals, which rely on tightly controlled spatial and temporal ROS fluctuations. We concurrently define physiological boundary conditions where robust antioxidant activity remains vital for plant survival under extreme stress. Rather than advocating for the complete suppression of ROS detoxification, our analysis advocates context-dependent fine-tuning of redox signaling networks. We also summarize emerging precision redox monitoring and genetic engineering tools, and outline translational breeding pipelines to develop climate-resilient crops that balance stress survival and yield stability. This work delivers novel conceptual perspectives to advance fundamental plant redox biology. Full article

The clinical translation of nucleic acids is severely hindered by multiple delivery barriers, such as enzymatic degradation, poor cellular uptake, endosomal entrapment, and rapid systemic clearance. Despite the remarkable therapeutic potential of these agents, conventional delivery systems often fail to address these challenges. Lipid nanoparticles (LNPs) have emerged as a versatile platform to overcome these obstacles, offering tunable physicochemical properties, high encapsulation efficiency, and pH-responsive endosomal escape. This review summarizes recent advances in LNP-based respiratory and gastrointestinal mucosal delivery of nucleic acids, with emphasis on formulation strategies for overcoming mucus and epithelial barriers. To overcome mucosal barriers, LNP studies have shown that keeping particle size below the local mucus mesh size (~100 nm), tuning surface charge toward near-neutrality via pH-responsive ionizable lipids, and maintaining a neutral, deformable, moderately PEGylated surface during the mucin transport stage can increase transmucosal diffusivity several-fold over conventional cationic LNPs. We further discuss current limitations and propose future directions, emphasizing the need for the integration of the pathological and physiological characteristics of specific mucosa with artificial intelligence (AI) platforms to develop intelligent and personalized delivery platforms with “spatiotemporal adaptive” capabilities. Full article

The intestinal barrier is a key interface maintaining host–microbial segregation and systemic homeostasis. A broad range of viruses, including enteric, respiratory, and systemic pathogens, can disrupt this barrier through effects on epithelial integrity, vesicular transport, immune responses, and microbial ecology. Whether these diverse insults converge on shared regulatory nodes or act through distinct virus-specific pathways that ultimately result in barrier failure remains unclear. Building on this premise, this review systematically delineates the molecular and cellular mechanisms underlying virus-induced disruption of the intestinal barrier. Viral infection disrupts epithelial integrity through multiple converging processes, including disassembly of tight junction architecture, activation of programmed cell death pathways, degradation of the mucus layer, impaired regeneration driven by intestinal stem cells, and dysregulation of transcellular transport. These processes are interconnected and collectively drive epithelial dysfunction and barrier breakdown. Beyond epithelial damage, we further highlight the pivotal contribution of host immune responses to barrier breakdown. Viral infection induces dysregulated cytokine production and aberrant immune activation, which amplify epithelial damage and further increase barrier permeability. In parallel, increasing evidence supports a bidirectional interaction between viral infection and gut microbiota dysbiosis, in which each process reinforces the other to accelerate barrier disruption and disease progression. We also discuss emerging therapeutic strategies aimed at restoring intestinal homeostasis, including antiviral therapies, host-targeted interventions, and microbiota modulation. Despite recent progress, key questions remain, particularly regarding mechanisms of failed barrier repair after viral clearance and the multilayered regulatory networks linking viruses, immunity, and the microbiota. Together, this review provides a framework for understanding virus-induced intestinal barrier dysfunction and identifies potential therapeutic nodes for intervention. Full article

To address the limitations of static-obstacle-based route planning in forest fire missions, this study develops a three-dimensional route-planning method for fixed-wing unmanned aerial vehicles (UAVs) that accounts for time-varying fire and smoke threats, complex terrain, and flight-dynamics constraints. A cellular automaton models fire spread with wind, slope, fuel, and moisture effects, while a Gaussian plume model estimates smoke concentration. The resulting burning and high-concentration smoke cells are encoded as dynamic three-dimensional threat envelopes and local grid masks. A hierarchical proximal policy optimization (H-PPO) architecture then combines a high-level stateful long short-term memory (LSTM) policy for route-subgoal generation with a pretrained low-level flight controller that produces continuous throttle and control-surface commands in JSBSim. In 100 independent simulation tests, the complete H-PPO model achieved a 100% task success rate, a mean terrain clearance of 771.92 m, and an average online decision time of 1.290 ms. Compared with A* and RRT*, H-PPO provided higher task reliability, greater mean terrain clearance, and lower online computational cost. The results show that hierarchical temporal decision making improves safety-prioritized planning in evolving fire and smoke environments, although conservative avoidance increases route length and mission duration. Further real-world and flight-test validation is required. Full article

Background/Objectives: The acute kidney injury (AKI) to chronic kidney disease (CKD) transition has been associated with a failed-repair proximal tubule (FR-PT) cell state. Hyperuricemia is an established CKD risk factor, but whether FR-PT cells have a coordinated metabolic signature reproducibly detectable across mouse models and human kidney disease remains unresolved. Methods: We assembled a pre-registered meta-analysis of 16 public mouse-kidney metabolomic cohorts (383 samples; five model classes; three injury phases) through a three-path harmonization pipeline. Convergent validation drew on KPMP single-nucleus RNA-seq (78,480 proximal tubule cells), two-sample Mendelian randomization of serum urate (102 instruments) against AKI/CKD/eGFR GWAS, and cross-cohort human plasma metabolomics across 2058 CKD/DKD patients. Results: Mouse meta-analysis identified uric acid (g = +2.70) and AICAR (g = +1.50) as the only cross-class conserved metabolites, with uric acid peaking during the AKI-to-CKD transition and returning to baseline in mouse CKD due to uricase clearance. Cross-class overlap between model classes was low (mean pairwise Jaccard = 0.109, below the pre-registered 0.20 threshold), invoking the pre-registered M-S1 stop rule: model-specific metabolic responses dominate, and the conserved signal is a small two-metabolite core superimposed on these largely model-specific programs. KPMP failed-repair PT cells exhibited transcriptional patterns consistent with coordinated four-arm purine-pathway dysregulation (de novo synthesis ↑, AMPK ↑, MOCOS ↑, URAT1 ↓), with this transcriptional pattern observed in both AKI and CKD donors (Spearman ρ = +0.900). Mendelian randomization was consistent with a possible causal contribution of serum urate to AKI/CKD/eGFR risk, with colocalization evidence at GCKR (PP.H4 = 1.000). Cross-cohort human plasma profiling across 2058 patients confirmed the systemic detectability of 29 purine-pathway metabolites in uricase-deficient humans (a translational-plausibility check, not validation of cellular source). Conclusions: The integrated data support a model in which FR-PT-associated purine-pathway reprogramming may contribute to the elevated urate signal observed during AKI-to-CKD transition, with uric acid as the candidate metabolic readout. Differences in uricase activity between mice and humans may help explain why chronic-phase urate signals are attenuated in mice but persist in humans. This work nominates a candidate cell-state metabolic readout of the AKI-to-CKD transition as a hypothesis for prospective testing; it does not establish causation, and therapeutic translation would require dedicated interventional studies. Full article

Oligonucleotide therapeutics represent an expanding class of medicines that can regulate gene expression, RNA processing, protein translation, immune signaling, and biomolecular recognition through sequence-specific or structure-dependent mechanisms. Despite clinical progress, their application remains constrained by nuclease degradation, rapid clearance, inefficient tissue and cellular delivery, endosomal sequestration, off-target activity, immune recognition, and mechanism-specific requirements for target engagement. Chemical modification is central to oligonucleotide therapeutic development because it can mitigate some of these limitations while influencing target affinity, protein binding, pharmacokinetics, and intracellular activity. This review examines chemical modification strategies to improve the biological stability and functional performance of therapeutic oligonucleotides and is organized around major classes of chemical modification, including phosphate and backbone-linkage modifications, sugar and conformational modifications, backbone-replacement analogs, and conjugation-based approaches. Rather than presenting these chemistries as uniformly beneficial, this review emphasizes that the same modification can be enabling in one therapeutic mechanism and disruptive in another, so its value cannot be judged apart from the modality and molecular architecture in which it is placed. Clinically successful oligonucleotide designs are likely to rely on combinations of chemical features, including modified backbones, modified sugars, stereochemical control, terminal stabilization, and ligand- or formulation-based delivery strategies. Understanding how these features interact is essential to develop more predictable and mechanism-appropriate oligonucleotide therapeutics. Full article

Ischemic stroke remains a leading cause of death and long-term disability worldwide. Although acute reperfusion therapies have improved outcomes in selected patients, effective strategies that directly promote neurovascular repair during the subacute and chronic phases remain limited. Vascular network remodeling in the peri-infarct region is increasingly recognized as a key process supporting tissue repair, blood–brain barrier restoration, and functional recovery after stroke. Microglia, as resident immune cells of the central nervous system, undergo dynamic morphological, metabolic, and functional changes after ischemic injury and participate in inflammation, phagocytic clearance, blood–brain barrier regulation, and tissue repair. Among repair-associated microglial states, microglia with M2d-like features have attracted increasing attention because of their potential association with immunoregulation and pro-vascular repair. However, whether repair-associated microglia with M2d-like features represent a distinct and stable microglial subtype after stroke remains unresolved. In this review, we summarize current evidence linking repair-associated microglial responses to vascular network remodeling after ischemic stroke, with particular emphasis on the conceptual value of the M2d-like state. We discuss putative mechanisms involving paracrine signaling, perivascular localization, metabolic reprogramming, and extracellular vesicle-mediated communication. We also evaluate therapeutic implications, including traditional Chinese medicine, extracellular vesicle-based strategies, and nanodelivery systems. However, current therapeutic evidence does not establish that these interventions specifically induce M2d-like microglial states. We highlight the need for rigorous validation of cellular identity, spatial localization, and functional vascular outcomes. Overall, the M2d-like framework provides a candidate perspective for understanding immune–vascular coupling after stroke, but further studies integrating single-cell omics, spatial mapping, lineage tracing, and functional vascular assessment are required to define the identity and functional contribution of repair-associated microglia with M2d-like features. Method: This article is a narrative review. The relevant literature was searched in PubMed from database inception to June 2026 using combinations of the terms “ischemic stroke,” “microglia,” “macrophage,” “vascular remodeling,” “angiogenesis,” “M2d,” “extracellular vesicles,” “traditional Chinese medicine,” and “nanomedicine.” Priority was given to original studies directly examining microglial or myeloid responses and vascular repair after ischemic stroke. Relevant review articles were included to provide conceptual background. Because direct evidence for M2d-like microglial responses after stroke remains limited, selected studies involving peripheral macrophages, tumor-associated macrophages, traditional Chinese medicine, extracellular vesicles, and nanomedicine were included as indirect or hypothesis-generating evidence. Evidence was interpreted according to the disease model, cellular source, and vascular outcomes examined, with stroke-specific microglial studies regarded as more directly relevant than evidence extrapolated from non-stroke or non-microglial models. Full article

Conventional antibiotics exhibit limited ability to penetrate host cell membranes, making intracellular bacterial infections difficult to eradicate completely. As naturally derived nanoscale membrane structures, bacterial extracellular vesicles (EVs) possess excellent biocompatibility and intrinsic transmembrane transport capability, thereby demonstrating unique advantages for in vivo drug delivery. The present study investigated the feasibility of using EVs derived from the avirulent Streptococcus suis T15 as novel carriers for ciprofloxacin delivery. We also comprehensively evaluated the biosafety and anti-infective efficacy of this nanodrug delivery system in vitro and in vivo. Cytotoxicity assays, live/dead cell staining, and hemolysis analyses demonstrated that T15-derived EVs at concentrations below 50 μg/mL did not cause significant cellular damage or hemolysis. Serum biochemical analyses in mice further confirmed the absence of obvious organ toxicity, indicating favorable biosafety within the tested concentration range. Ciprofloxacin was successfully loaded into EVs using a combination of ultrasonication and electroporation, achieving a drug concentration of 438.6 μg/mL and a loading efficiency of 10.96%. The ciprofloxacin-loaded EVs (EV-CIP) exhibited significantly greater antibacterial activity than free ciprofloxacin against both intracellular bacteria and fluoroquinolone-resistant strains exhibiting efflux pump activity. Evaluation in animal infection models showed that EV-CIP markedly reduced mortality in infected Galleria mellonella larvae. It also decreased bacterial burdens in multiple mouse organs and significantly alleviated histopathological damage. These results collectively suggest that EVs derived from the avirulent S. suis T15 were safe and effective within the tested concentration range and experimental conditions. The EV-based ciprofloxacin delivery system substantially enhanced the clearance of intracellular pathogens and fluoroquinolone efflux pump-positive bacteria, suggesting its potential application in the treatment of difficult-to-treat bacterial infections. This study provides a theoretical and experimental basis for the further development of novel EV-based anti-infective drug delivery strategies for livestock and poultry. Full article

Reversible genetic medicines are emerging as controllable alternatives to permanent genome editing by enabling programmable modulation of RNA sequence, transcript abundance, chromatin state, and gene expression without irreversible genomic alteration. However, reversibility is not a single binary property: transient editor exposure, decay of the molecular effect, recovery of cellular function, and clinical capacity to stop, redose, or counteract treatment may diverge. This review therefore distinguishes mechanistic, functional, and clinical reversibility while examining targeted delivery systems for RNA-editing and epigenome-editing therapeutics. Key payloads include ADAR-recruiting oligonucleotides, CRISPR-Cas13 RNA editors, guide RNAs, chemically modified RNAs, editor-encoding mRNAs, dCas9 transcriptional regulators, DNA methylation editors, histone-modifying systems, and CRISPRoff-like platforms. We evaluate extracellular and intracellular delivery barriers, including nuclease degradation, immune recognition, renal clearance, liver uptake, cellular entry, endosomal escape, cytoplasmic release, nuclear localization, chromatin access, editing-window duration, off-target activity, immunogenicity, repeat-dosing feasibility, manufacturing, quality control, potency assays, and regulatory translation. Overall, delivery systems for reversible genetic medicines should be judged by tissue selectivity, functional editing, duration of action, reversibility after treatment withdrawal, safety, manufacturability, and clinical controllability. Full article

Extracellular vesicles have emerged as promising cell-free therapeutic agents for wound healing due to their remarkable ability to modulate inflammatory responses, promote angiogenesis, and enhance tissue regeneration. These biological nanocarriers deliver bioactive cargo, including regulatory miRNAs, proteins, and lipids, to recipient cells, thereby modulating key signaling pathways governing tissue repair. However, the clinical translation of extracellular vesicle (EV)-based therapies is substantially limited by challenges in delivery efficiency. Local drug delivery systems (LDDSs) offer several key advantages, including reduced clearance by the reticuloendothelial system, enhanced biodistribution to wound sites, prolonged local residence time, and precise spatial targeting of therapeutic effects. This review systematically summarizes recent advances in EV-based therapies for wound repair, with a particular focus on in situ forming and implantable LDDSs, such as stimuli-responsive hydrogels. We comprehensively discuss the molecular and cellular mechanisms through which EVs facilitate healing across all phases of wound repair. Furthermore, we critically evaluate the evolution of these delivery platforms, transitioning from conventional passive-release systems to advanced stimuli-responsive hydrogels and microneedle systems, assessing their design rationale and integration with EV biology. We also address key translational challenges and opportunities: scalable manufacturing, standardized quality control, and regulatory pathways, offering a forward-looking view on clinical implementation of EV-LDDS hybrids in precision regenerative therapy. Full article

Chronic kidney disease is increasingly recognised as a systemic disorder with important neurological consequences, including cognitive impairment. However, the field remains challenging because CKD-related cognitive decline involves diverse uremic toxins, overlapping vascular, inflammatory, metabolic, endothelial, and neurodegenerative pathways, inconsistent cognitive screening practices, and no unified treatment strategy. Within this context, the kidney–brain axis provides a useful framework for integrating renal dysfunction, toxin retention, systemic inflammation, blood–brain barrier disruption, and cognitive vulnerability. Of these mechanisms, uremic neurotoxicity offers a biologically credible connection between compromised renal clearance and cerebral dysfunction. Retained solutes such as indoxyl sulfate, p-cresyl sulfate, indole-3-acetic acid, trimethylamine-N-oxide, urea, guanidino compounds, lanthionine, quinolinic acid, and homocysteine may induce endothelial injury, oxidative stress, neuroinflammation, mitochondrial dysfunction, excitotoxicity, and glial activation. Although these pathways are supported by experimental and translational studies, direct causal evidence in humans remains limited, and most clinical data should currently be interpreted as associative rather than definitive proof of causality. These processes converge on neuronal and synaptic vulnerability and may elucidate the distinctive cognitive profile associated with chronic kidney disease, particularly deficits in attention, processing speed, and executive function. This review summarizes the most recent evidence on the epidemiology and clinical phenotype of cognitive impairment in chronic kidney disease. It also discusses the molecular and cellular mechanisms of uremic neurotoxicity and examines new biomarkers of the kidney–brain axis, including neurofilament light chain, glial fibrillary acidic protein, brain-derived neurotrophic factor, tight junction proteins, and uremic toxins. However, these biomarkers remain insufficiently validated for routine clinical use, as their interpretation is complicated by reduced renal clearance, systemic inflammation, comorbid vascular disease, methodological heterogeneity, and the lack of longitudinal studies linking biomarker changes to cognitive outcomes. Therapeutic strategies targeting uremic toxins remain compelling from a mechanistic standpoint, but they are not yet fully developed in clinical practice. Subsequent research ought to amalgamate toxin profiling, cognitive phenotyping, neuroimaging, endothelial and inflammatory biomarkers, alongside patient-centered outcomes. Integrating cognitive assessment into nephrology care may enhance risk stratification, collaborative decision-making, and personalised management for patients with chronic kidney disease. Full article

Xanthohumol (XN), a prenylated chalcone isolated from Humulus lupulus L., exhibits a wide range of biological activities, including antioxidant, anti-inflammatory, and chemopreventive effects. However, its therapeutic application is limited by poor aqueous solubility, low chemical stability, and rapid clearance from the systemic circulation. The present study aimed to develop and characterize a novel nano-sized drug-delivery system for XN that combines favourable colloidal stability, efficient encapsulation, sustained release, and reduced recognition by macrophages (“stealth-like” properties). To achieve this, XN-loaded cationic liposomes were coated with two marine polysaccharides, iota-carrageenan (CAR) and fucoidan (FUC), followed by Ca²⁺-mediated cross-linking. Liposomes were prepared by the ethanol injection method, and formulation parameters were optimized using a 2³ + 1 full factorial design. Surface modification and cross-linking conditions were further optimized through polyelectrolyte titration and a Taguchi L9 orthogonal array. The resulting nanocarriers were evaluated for particle size, polydispersity, ζ-potential, encapsulation efficiency, release behavior, and cellular uptake. Both coatings significantly prolonged XN release compared with uncoated liposomes, with CAR-coated vesicles providing the most sustained release (≈55% over 48 h). In RAW264.7 macrophages, 50 µg/mL CAR-coated liposomes reduced cellular uptake by approximately 74% following 1-h incubation relative to uncoated controls and maintained this reduction over 2 h whereas FUC-coated vesicles afforded only transient early evasion. The cross-linked iota-carrageenan coating thus represents a promising strategy for conferring stable “stealth-like” characteristics to XN-loaded liposomes intended for prolonged drug delivery. Full article

Chronic rhinosinusitis (CRS) is an inflammatory disease of the sinonasal mucosa whose pathogenesis is characterized by complex interactions of immunological and environmental factors. The maintenance of normal sinonasal function requires a balance of sinus ostial patency, mucociliary clearance, and mucus secretion, and disruption of this balance can lead to CRS. Although many studies have examined the pathophysiology of CRS, the role of reactive oxygen species (ROS) remains incompletely understood. In this review, we analyzed 22 studies of CRS that examined the effects of ROS on epithelial barrier function, local immune responses, and tissue remodeling. The results from in vitro studies, animal models, and human tissue analyses suggest that ROS are not merely by-products of inflammation, but appear to function as key mediators in the pathophysiology of CRS, particularly in the formation and persistence of the CRS phenotype with nasal polyps (CRSwNP). In particular, CRSwNP is characterized by increased activity of enzymes in the dual oxidase (DUOX) and NADPH oxidase (NOX) families, mitochondrial dysfunction, and decreased activity of superoxide dismutase (SOD) and peroxiredoxin 2 (PRDX2). At the molecular level, these alterations increase the generation of ROS and impair antioxidant defense. At the cellular level, these alterations disrupt the epithelial barrier, activate inflammasomes, increase pyroptosis, and induce the formation of neutrophilic and eosinophilic extracellular traps. These changes culminate in the epithelial–mesenchymal transition (EMT), with the formation of nasal polyps and tissue remodeling. Increased oxidative stress can also occur in CRS without nasal polyps (CRSsNP), but this phenotype appears to have relatively preserved antioxidant defense systems, which may partly explain the more limited structural remodeling. External stimuli, such as fungal proteases, bacterial toxins, and certain antibiotics, can also increase the production of ROS and may contribute to disease chronicity. Taken together, the level and pathophysiological roles of ROS differ in the two primary phenotypes of CRS. Further mechanistic studies are needed to clarify the specific alterations of redox pathways in these two phenotypes and to develop novel therapeutic strategies that target ROS. Full article

Respiratory mucosal vaccination can induce robust humoral and cellular immune responses, as well as effective mucosal immunity at the primary site of pathogen entry, and has been shown to provide superior protection against respiratory viral infections compared with traditional approaches. Among current vaccine technologies, mRNA vaccines offer unique advantages, including rapid development, flexible antigen design, and potent immunogenicity. However, efficient mucosal delivery of mRNA remains challenging due to biological barriers within the respiratory tract, including mucus clearance, limited cellular uptake, and instability during aerosolization. Furthermore, mRNA formulations intended for respiratory mucosal delivery require more stringent safety and tolerability profiles. Recent advances in nanoparticle engineering have accelerated the development of mRNA delivery systems optimized for respiratory mucosal immunization. This review aims to evaluate how nanoparticle engineering strategies can overcome respiratory mucosal barriers and improve the safety, stability, delivery efficiency, extrahepatic expression, and immunogenicity of mRNA vaccines and therapeutics. We summarize recent progress in engineered mRNA nanoparticle platforms for respiratory mucosal immunity, encompassing modified lipid nanoparticles (LNPs), polymer-based mRNA nanoparticles, and hybrid nanoparticle systems, including lipid-inorganic, polymeric hybrid, and lipid-extracellular vesicle (EV) nanoparticles. We further discuss optimization strategies for mucosal mRNA delivery, including the incorporation of appropriate adjuvants, the development of polyethylene glycol (PEG) alternatives, and advanced delivery approaches. Finally, we highlight current challenges and future directions for the rational design of next-generation mRNA nanoparticle platforms that can induce durable and broadly protective mucosal immunity against respiratory viral infections. Full article

Chronic ultraviolet B (UVB) radiation drives cutaneous photoaging—clinically manifesting as erythema, edema, scaling, deep wrinkling, loss of elasticity, and barrier disruption—through mitochondrial reactive oxygen species (mtROS) overproduction and quality-control failure. Here we identify α-ketoglutarate (AKG; also known as 2-oxoglutarate), a TCA-cycle intermediate and essential co-substrate for α-ketoglutarate-dependent dioxygenases (α-KGDDs), as a metabolic corrector of mitochondrial redox homeostasis in UVB-induced photoaging. In a 10-week chronic UVB SKH1 hairless mouse model, microneedle-assisted transdermal delivery of AKG dose-dependently attenuated macroscopic erythema, scaling, and erosive lesions, restored skin barrier function and dermal elasticity, preserved epidermal–dermal architecture, and protected collagen and elastic fiber integrity, with efficacy comparable to all-trans retinoic acid. Mechanistically, AKG reactivated α-KGDD/prolyl hydroxylase (PHD) catalytic function and promoted proteasomal clearance of aberrantly stabilized HIF-1α under normoxia; this was accompanied by restored AMPK Thr172 phosphorylation downstream of constitutive LKB1 and recovery of PGC-1α-driven mitochondrial biogenesis. AKG preferentially attenuated mitochondrial superoxide over total cellular ROS through a co-substrate-mediated mechanism distinct from direct radical scavenging, and its protective effects were largely abrogated by DMOG (an α-KGDD inhibitor) or compound C (an AMPK inhibitor). These findings position AKG, delivered via microneedle-assisted topical application, as a candidate metabolite-based intervention targeting the α-KGDD/HIF-1α/AMPK axis for photoaging. Full article