Biology subjects

Han, Z.

Publications and source records attributed to Han, Z..

At least 19 recordsLinked to original sources

bioRxiv2026

Auditory tracking magnitude, temporal alignment, and anatomical distribution during wakefulness and propofol-based anesthesia in human sEEG

General anesthesia attenuates auditory responses, but response magnitude alone does not describe how residual activity aligns with sound over time or varies across the brain. We jointly characterized these aspects of auditory tracking using stereoelectroencephalography (sEEG) in 13 patients with drug-resistant epilepsy during wakefulness and clinically defined unresponsiveness under propofol-based anesthesia. The same rhythmic humming sequences were presented at approximately 1.61 Hz in both sessions. During anesthesia, stimulus-rate power showed widespread reductions and phase alignment with the stimulus rhythm was less consistent, although responses remained detectable at some recording channels. During wakefulness, response strength decreased with cortical surface distance from posteromedial Heschl's gyrus; this distance-response relationship was weaker during anesthesia. In a contrastive learning analysis (CEBRA), low-dimensional embeddings derived from anesthesia recordings yielded lower acoustic-envelope decoding accuracy on held-out data and lower consistency across model fits. Together, these findings characterize how attenuated auditory tracking is expressed jointly in response magnitude, temporal alignment, and anatomical distribution.

neuroscience↗

bioRxiv2026

Biosurfactant production under cold-saline stress is a strain specific trait independent from phylogeny and biosynthetic gene content

Abstract Microbial genomes code for far more biosynthetic potential than a single cell typically expresses, but the environmental and cellular controls that determine whether the latent capacity is realised remain poorly understood. Biosurfactants, surface-active metabolites proposed to aid survival in cold and saline habitats, exemplify this gap: capacity is often inferred from genomes or detected chemically, but is rarely linked to the specific conditions that stimulate its production in the same organisms. Here we combine whole-genome sequencing, untargeted LC-MS/MS metabolomics, and quantitative surface-tension assays across 25 bacterial isolates isolated from the cold, hypersaline Qaidam Basin (a terrestrial analogue for ancient Mars) and contrasting marine environments. We show that biosurfactant production is not a fixed lineage trait but a regulated, strain-specific response that emerges under combined cold and salt stress. This response is structured into three tiers: genomic capacity defines the accessible chemical space; the genomic complement of pathway-regulator genes tracks responsiveness; strain-level physiological state determines realised output. Regulatory-gene content, rather than biosynthetic-cluster count, predicted surfactant production across strains. Production was amplified by low temperature and high salinity and showed little phylogenetic signal, with near-clonal strains differing in their stress-response. These findings reshape biochemical adaptation in extreme environments as a problem of conditional activation, not only of genomic potential, but of cellular systems that permit its expression, which requires looking beyond biosynthetic-gene content to the cellular factors that determine whether that potential is expressed.

microbiology↗

bioRxiv2026

Functional recovery of vitrified and nanowarmed human-scale pig kidneys

Organ transplantation is critically constrained by the short preservation window for donor organs, limiting allocation and contributing to organ discard and waitlist mortality. Cryogenic organ banking could extend preservation from hours to months or years, but ice formation, thermal stress and cryoprotectant toxicity become increasingly difficult to control as organ size increases. Vitrification and nanowarming have enabled long-term preservation and transplantation of rodent kidneys but have not been demonstrated at the scale of clinically relevant organs. Here we show that vitrification and electromagnetic nanowarming enable long-term cryogenic storage and functional recovery of human-scale porcine kidneys. Kidneys 100-fold larger than previously nanowarmed kidneys were successfully recovered after storage at -150 {degrees}C for up to one year. A new cryoprotectant formulation and multithermic perfusion strategy enabled ice-free vitrification at cooling rates achievable in large kidneys, while controlled cooling with annealing and staged volumetric nanowarming limited thermal stress and enabled rapid rewarming without cracking. Rewarmed kidneys demonstrated vascular, metabolic and excretory function during normothermic perfusion, with limited histological injury, and reperfused homogeneously and produced urine immediately after transplantation. Functional recovery approached static cold storage outcomes across several measures and was similar to that of kidneys exposed to cryoprotectant alone, suggesting minimal additional functional injury from vitrification, cryogenic storage and nanowarming. These findings overcome major scale and storage-duration barriers to organ cryopreservation and establish a path toward organ banking on timescales far beyond those of conventional preservation.

bioengineering↗

bioRxiv2026

Charting sex divergence in the human brain across the lifespan

Biological sex fundamentally shapes human brain organization, but sex-specific normative neuroanatomical trajectories across the lifespan remain largely uncharted. Here, we constructed independent, sex-specific lifespan brain charts using structural neuroimaging data from 59,915 healthy individuals (29,760 males and 30,155 females) ranging in age from 266 postconception days to 100 years. By examining 296 structural phenotypes across global, cortical, and subcortical measures, these models revealed widespread sex differences in maturational timing, with males reaching peak milestones later than females. These trajectories demonstrate that sex differences evolve dynamically, with phenotype-specific windows of emergence and maximal separation. Compared with conventional sex-pooled references, sex-specific models achieved superior predictive accuracy and reduced misestimation of individual deviations in healthy populations. Across five neuropsychiatric conditions, sex-specific models improved the detection of extreme deviations and revealed both shared and sex-dependent patterns of disorder-related neuroanatomical abnormalities. These sex-specific charts establish tailored normative references for assessing brain development, ageing, and disease.

neuroscience↗

bioRxiv2026

A climate-resilient microalga, Desmodesmus ecotolerans sp. nov., for biophotovoltaic applications

Microalgae are promising biological platforms for sustainable energy production because they can convert photosynthetic activity into electricity in biophotovoltaic (BPV) systems. Identifying strains that grow well at elevated temperatures and under reduced irradiance is an important step toward BPV applications in seasonally variable environments. Microalgae were isolated from Seondong Lake (Seoul, Republic of Korea) during three sampling periods and screened for growth at different temperatures. Among 45 isolates, KHUC-11 showed the highest weighted growth index based on growth rates at 25, 30, and 35 under dark conditions and was selected for further characterization. Phylogenetic reconstruction of the 45S rRNA gene cluster, internal transcribed spacer 2 (ITS2) secondary-structure comparison, and morphological characterization supported the description of KHUC-11 as Desmodesmus ecotolerans sp. nov. D. ecotolerans produced more biomass than Chlamydomonas reinhardtii CC-125 under both moderate- and low-light conditions. Under low light, its final dry biomass concentrations were 1.81 and 1.58 times those of CC-125 under mixotrophic and photoautotrophic conditions, respectively. Despite its smaller cell size, D. ecotolerans showed higher photosynthetic performance than CC-125, and screen-printed electrode (SPE)-based electrochemical assays demonstrated enhanced anodic current generation and CV-derived estimated power output. Taken together, these findings identify D. ecotolerans as a novel climate-resilient Desmodesmus species with bioelectrochemical properties that support further evaluation for BPV applications.

microbiology↗

bioRxiv2026

Charge-driven remodelling of monomeric Tau determines its phase behaviour

Tau transitions from a functional microtubule-stabilising monomer into pathological aggregates in tauopathies. However, the molecular mechanism by which soluble Tau transitions into insoluble aggregates remains poorly understood. Here, we show that modulation of Tau internal charge-charge interactions by pH and ionic strength is sufficient to remodel its monomeric conformational ensemble and direct its subsequent self-assembly pathway. By subjecting the expanded random coil-like 2N4R Tau to prolonged incubation at low ionic strength and near its isoelectric point, we generated a long-lived compact molten globule-like monomer. Although both expanded and compacted conformations remain disordered, they differ markedly in their local solvent accessibility and dynamics. We show that monomer compaction is stabilised by weak interactions that remodel the solvent accessibility of the microtubule-binding repeat region and its flanking sequences. Consequently, these conformational changes alter Tau phase behaviour, inhibiting liquid-liquid phase separation and amyloid fibril formation. Our findings demonstrate that charge-driven remodelling of the Tau conformational ensemble determines its phase behaviour and provide a mechanistic insight into the molecular events underlying tauopathies.

biophysics↗

bioRxiv2026

Deep reinforcement learning-driven discovery of a MsbA-targeted small-molecule antibiotic for the treatment of Acinetobacter baumannii infection

Antibiotics with new mechanisms are highly pursued to address the threat of infections caused by drug-resistant Gram-negative bacteria. Targeting MsbA, a key protein of the lipopolysaccharide biosynthesis pathway, represents a promising strategy to discover new classes of antibiotics. However, currently available MsbA-targeted molecules either lack sufficient potency or have unfavorable properties, necessitating expansion of chemical space. In this study, we chose the most promising cerastecin Cpd 4 as the template, and used two Artificial Intelligence (AI)-based tools, i.e. Link-INVENT and AutoMolDesigner for molecular design, performed chemical derivatization and antibacterial activity evaluation, which led to the discovery of Y-11 (MIC for A. baumannii: 0.5 g/mL). Encouragingly, Y-11 showed equivalent potency to Cpd4 for carbapenem-resistant A. baumannii, and less cytotoxicity and hemolysis as well as lower spontaneous resistance frequency. In vivo efficacy study demonstrated that Y-11 could effectively reduce bacterial loads in the mice infected by A. baumannii. The following mechanism study including molecular dynamics simulation, biochemical assay, and transmission electron microscope (TEM) analysis suggested that Y-11 inhibited the transport of lipooligosaccharide and impaired the formation of outer membrane, probably by competitively binding to the substrate binding site of MsbA and modulating ATPase activity. Taken together, we have discovered a MsbA-targeted small molecule Y-11 via AI-driven drug design, which provides a foundation for future antibiotic development.

biochemistry↗

bioRxiv2026

Geometric characterization of the HSV - 1 glycoprotein B - amyloid β interaction in Alzheimer's disease using Forman-Ricci curvature

Alzheimer's disease is characterized by the accumulation and aggregation of amyloid-{beta}(A{beta}), but the molecular mechanisms linking environmental and infectious factors to A$\beta$ conformational changes remain incompletely understood. Herpes simplex virus type 1 (HSV-1) has been proposed as a potential contributor to AD pathology, and interactions between the viral glycoprotein B (gB) and A$\beta$ may influence the conformational behaviour of the peptide. Molecular dynamics (MD) simulations provide atomic-scale information on such interactions, but conventional structural descriptors may not fully capture changes in the organization of residue interaction networks. Here, we introduce a graph-geometric framework based on Forman-Ricci curvature to characterize the evolution of residue interaction networks during MD simulations. Each simulation frame is represented as a residue interaction graph based on C--C contacts, and residue-wise curvature profiles are analysed across time. We apply the framework to A{beta}1-42 in isolation and in complex with HSV-1 gB. Conventional MD analyses indicate stable association of the simulated complex, favourable interaction energetics, and conformational changes in A{beta}, including a transition from -helical structure toward {beta}-turn-rich conformations over the simulated timescale. Forman-Ricci curvature reveals pronounced and spatially localized remodelling of the A{beta} residue interaction network in the complex, with the strongest changes concentrated in the C-terminal region. These regions also exhibit reduced temporal curvature fluctuations and progressively distinct geometric behaviour throughout the simulation. Hierarchical clustering further identifies cooperative groups of residues with coordinated curvature dynamics, including a prominent C-terminal domain. Together, these results demonstrate that Forman-Ricci curvature provides a complementary description of biomolecular dynamics by capturing changes in the geometric organization of residue interaction networks that are not directly represented by conventional structural descriptors. The framework provides a general computational approach for studying network-level structural remodelling in protein molecular dynamics and offers a quantitative perspective on the conformational consequences of HSV-1 gB--A{beta} association.

bioinformatics↗

bioRxiv2026

Inflammatory proteolysis generates pathogenic APOL1 fragments with distinct intracellular toxicities in podocytes derived from children with HIV associated nephropathy

APOL1 risk variants are the strongest genetic determinants of HIV-associated nephropathy (HIVAN), yet the mechanisms linking inflammation to APOL1-mediated podocyte injury remain poorly understood because authentic patient-derived human disease models are lacking. Using urine-derived podocytes established from children with HIVAN and endogenous APOL1 reporter cell lines derived from these cells, we identified a previously unrecognized pathway of inflammatory, cathepsin-dependent APOL1 proteolysis. Endogenous APOL1 cleavage was detected in patient-derived podocytes, whereas reporter cell lines enabled the identification and functional characterization of N-terminal and C-terminal APOL1 fragments with distinct intracellular localization and pathogenic functions. The nuclear N-terminal fragment activated inflammatory transcriptional programs and promoted podocyte injury, whereas the membrane-associated C-terminal fragment mediated membrane toxicity and remained susceptible to pharmacologic inhibition by inaxaplin. Cathepsin S directly cleaved APOL1 in vitro, linking inflammatory signaling to APOL1 fragmentation. These findings identify inflammatory APOL1 proteolysis as a mechanism that partitions APOL1 toxicity into distinct pathogenic programs and nominate APOL1 processing as a therapeutic target for HIV-associated and other APOL1-mediated kidney diseases.

cell biology↗

bioRxiv2026

Comparative analysis of microglia-targeted AAVs reveals capsid choice drives efficiency in vitro but has limited impact in vivo

Microglia play key roles in brain development, homeostasis, and neurodegeneration. Although multiple strategies for viral gene delivery to microglia have been reported, they have not been directly compared. Here, we developed microglia-targeting AAV capsids and benchmarked them against existing approaches. The novel capsids exhibit improved transduction efficiency in cultured mouse and human microglia, as well as neurons and astrocytes. However, when we compared microglial transduction efficiency of the novel capsids with published engineered and naturally occurring capsids after intracranial injection, all capsids achieved efficient and specific transduction when paired with a genome incorporating IBA1 promoter and miR-124 target sites. In contrast, CAG promoter did not support efficient microglial transduction. Moreover, blood-brain barrier- crossing capsids carrying IBA1 promoter and miR-124 target sites efficiently transduced microglia at high doses but exhibited off-target expression. Together, our work provides improved capsids for in vitro manipulation of microglia and establishes viral genome design, not capsid identity, as the principal determinant of efficient in vivo microglial targeting.

neuroscience↗

bioRxiv2026

Spatiotemporal coordination of specialized cerebellar networks supports episodic memory in older adults

Episodic memory decline in ageing is typically attributed to the cortico-hippocampal system, yet the cerebellums specific contribution via cerebellar-cerebral circuits remains underexplored. We analysed task-based fMRI data from 821 older adults, including a longitudinal subset of 78 participants followed for four years. Using sparse dictionary learning on task-responsive activity, we identified three non-motor networks: a bilateral lobule VI/Crus I mnemonic-monitoring network, a right lobule Crus I/II default-mode-aligned network, and a right lobule VIIb/VIIIa evidence-evaluation network. While network recruitment varied with task demands and associated with memory performance, phase-specific static cerebellar-cerebral functional connectivity showed stable organization but limited behavioural specificity. In contrast, dynamic functional connectivity patterns effectively distinguished memory-performance groups. Crucially, greater instability in dynamic functional connectivity during encoding predicted longitudinal retrieval slowing. These findings suggest that preserved episodic memory in older adults is supported by the spatiotemporal coordination of specialized cerebellar networks with distributed cerebral networks.

neuroscience↗

bioRxiv2026

Complex coacervation reshapes the aggregation landscape of tau

Biomolecular condensates are increasingly implicated in protein aggregation, yet their contribution is often reduced to that of concentrating reactants. Whether the phase state of a protein itself changes how it aggregates remains unclear. Using complex coacervates of a tau repeat-domain construct (K12) with heparin, we show that phase separation does not simply accelerate tau aggregation but redirects it along a distinct kinetic regime. Amyloid nucleation and growth are largely associated with the condensed phase, where intact phase-separated mixtures nucleate with a markedly shortened lag phase, whereas the corresponding dilute phase contributes little to overall amyloid formation. Aggregation kinetics in this regime become largely decoupled from total protein concentration. Because phase equilibrium pins the composition of the dense phase, additional tau partitions largely into the coexisting dilute phase without substantially altering the reacting population. This weak concentration dependence provides a kinetic signature of compartmentalized aggregation, and it recurs across chemically distinct coacervates formed with heparin, RNA, and polyglutamate, pointing to a general feature of coacervate-mediated tau assembly rather than a heparin-specific effect. Aggregation within coacervates also yields fibrils with altered morphology and secondary structure, suggesting access to alternative regions of the assembly landscape, and shows reduced sensitivity to bulk pH perturbations. Together, these results show that condensation changes tau aggregation by defining the local reaction environment: phase equilibrium buffers the dense-phase composition, in turn altering aggregation kinetics and the properties of the amyloid formed.

biophysics↗

bioRxiv2026

Dynamic interaction between tentacle-tethered microdomains in Integrator and NELF regulates the promoter-proximal pause checkpoint

Negative Elongation Factor (NELF) and Integrator are general regulators of transcriptional pausing and premature termination at the beginning of protein-coding genes. While NELF is a key pausing factor, Integrator triggers premature termination of dysfunctional RNAPII complexes. Here, we identify a direct interaction between the plant homeodomain (PHD) finger of Integrator subunit 12 (INTS12) and a previously unrecognized C-terminal domain (CTD) in the flexible tentacle of NELF-A. Mutation of either domain disrupts the interaction, and although RNAPII-associated pausing complexes still form, they are dysfunctional. Importantly, while deletion of the INTS12 PHD finger functionally mimics Integrator loss, a single point mutation in NELF-A CTD instead mimics loss of NELF, suggesting the presence of competitive interactions. Together, our findings uncover a novel mode of PHD finger binding and outline how an interaction between Integrator and NELF regulates transcriptional pausing and premature termination.

cell biology↗

bioRxiv2026

Effect of CSFV on Differential Genes of Histone Lactylation at H3K18 in the PI3K-AKT Signaling Pathway

Classical swine fever (CSF) is a highly contagious disease caused by Classical swine fever virus (CSFV), posing a serious threat to the global swine industry. This study aimed to investigate the effect of CSFV on differential genes of histone lactylation at the H3K18 site in the PI3K-AKT signaling pathway. The site with the most significant change in histone lactylation antibody level was screened by Western blot. Omics analysis was performed using CUT&Tag technology to identify differential genes in the PI3K-AKT pathway between the CSFV-infected group and the mock group, followed by validation using RT-qPCR. Functional analysis of significantly differential proteins was conducted, and the protein expression level of THBS4 was detected by Western blot. The results showed that after CSFV infection of 3D4/21 cells, the H3K18la site exhibited the most significant difference in antibody level. A total of 8,859 differential genes at the H3K18la site were identified by CUT&Tag analysis, including 6,349 up-regulated genes and 2,510 down-regulated genes. Further focusing on the PI3K-AKT signaling pathway, 10 differential genes were identified, comprising 6 up-regulated genes and 4 down-regulated genes. Compared with the control group, the mRNA expression levels of CD19, LAMA1, PDGFRA, BDNF, ANGPT4, and THBS4 were up-regulated in the CSFV-infected group, while FOXO3 and NRTN were down-regulated. Western blot results showed that the protein expression level of THBS4 increased after CSFV infection. These findings lay an important foundation for understanding the molecular mechanisms regulating viral replication and immune evasion, and have significant scientific implications and potential application value.

microbiology↗

bioRxiv2026

Iron Regulates CD4 T Cell Quiescence by Controlling TGF-β Production

Transforming growth factor-{beta} (TGF-{beta}) regulates CD4 T cell quiescence, activation, and regulatory T cell differentiation, but its role in T cell iron metabolism is poorly defined. Here, we investigated whether TGF-{beta} regulates iron homeostasis and how iron overload alters TGF-{beta} responsiveness. During T cell activation, TGF-{beta} enhanced survival but markedly reduced proliferation. These effects were accompanied by decreased CD71 expression and cytosolic iron availability, as well as increased mitochondrial iron accumulation. Genetic deletion of TGF{beta}R1 reversed these changes, demonstrating that TGF-{beta} regulates CD4 T cell iron homeostasis through TGF{beta}R1-dependent signaling. Iron-overloaded CD4 T cells lacking the heme exporter FLVCR1 exhibit hypersensitivity to TGF-{beta}, increased TGF-{beta} secretion, and sustained TGF{beta}R1 expression upon activation. Pharmacologic inhibition of TGF{beta}R1restored proliferation, CD71 expression, and iron levels in FLVCR1-deficient cells. Although TGF-{beta} selectively induced total and mitochondrial ROS levels in FLVCR1-deficient cells, antioxidant treatment or Nox2 inhibition did not rescue this phenotype, suggesting that ROS is associated with, but not sufficient to explain, TGF-{beta} hypersensitivity. Acute FeSO4-induced iron overload partially recapitulated the phenotype of FLVCR1-deficient cells, although TGF{beta}R1 expression and TGF-{beta} production differed. Finally, regulatory T cells generated in vitro in the presence of TGF-{beta} displayed reduced iron acquisition, and excess iron impaired FoxP3 induction. Together, this work identifies TGF-{beta} as a context-dependent regulator of CD4 T cell iron homeostasis.

immunology↗

bioRxiv2026

The HOG MAPK - Transcription Factor CsAtf1 - CsErg5B Regulatory Module Mediates Conidial Germination and Fludioxonil Sensitivity in Colletotrichum siamense

Colletotrichum siamense is a predominant causal agent of anthracnose in rubber tree and numerous economically important crops, causing severe yield losses worldwide. Conidial germination represents a critical early step for successful infection, while the high-osmolarity glycerol (HOG) MAPK pathway and ergosterol biosynthesis individually govern fungal development, stress adaptation and fungicide responses. However, the molecular crosstalk between these two modules remains largely elusive in phytopathogenic fungi. Here, we identified CsErg5B, a sterol C-22 desaturase homolog, as a direct target of the HOG- regulated transcription factor CsAtf1 in C. siamense. CsErg5B was indispensable for ergosterol biosynthesis, conidial germination, appressorium formation, and full virulence. The {Delta}CsErg5B mutant showed increased conidiation but severely impaired germination, and exhibited elevated resistance to fludioxonil while hypersensitivity to azole fungicides. Epistasis analysis using the {Delta}CsErg5B/{Delta}CsCyp51G1 double mutant - where CsCyp51G1 serves as another downstream target of CsAtf1 - revealed that CsErg5B functions as the predominant downstream effector of CsAtf1 in modulating conidial development and fludioxonil sensitivity. Furthermore, overexpression of CsErg5B significantly rescued the defects in conidial germination and fludioxonil sensitivity in both {Delta}CsAtf1 and {Delta}CsPbs2 mutants. Taken together, our findings uncover a HOG MAPK - CsAtf1 - CsErg5B regulatory axis that connects HOG MAPK signaling to ergosterol homeostasis, thereby governing conidial germination and fungicide sensitivity in C. siamense. This study provides novel insights into the regulatory network underlying fungal development and fungicide response, and offers promising molecular targets for the integrated management of plant anthracnose.

microbiology↗

bioRxiv2026

Structural Basis of Ligand-Specific Orthosteric-Allosteric Coupling and Sensory Tuning in the Human Bitter Taste Receptor TAS2R14

The bitter taste receptor TAS2R14 recognizes hundreds of structurally diverse ligands, yet the mechanisms governing its broad promiscuity, graded agonist efficacy, and multi-site regulation remain unclear. Here, we report cryo-EM structures of TAS2R14-Gi1 complexes bound to 3,5-diiodosalicylic acid (DA), flufenamic acid (FA) and aristolochic acid (AA) at resolutions of 2.44 [A], 2.39 [A], and 2.69 [A], with a clear efficacy hierarchy of AA > FA > DA. Transmembrane helix 6 (TM6) acts as a core regulatory hub, with agonist binding triggering 12 [A] lever-like TM6 rearrangements to reshape receptor interfaces and modulate G-protein coupling strength. We also identify cholesterol hemisuccinate (CHS) as a new TAS2R14 orthosteric agonist, selectively potentiating DA-mediated signaling potency by [~]5-fold via allosteric-orthosteric coupling without affecting FA or AA. Our findings show TM6 dynamics unify TAS2R14s key functional features, advancing insights into bitter receptor activation and sterol regulation.

molecular biology↗

bioRxiv2026

Melanin regulates mitochondrial dynamics, metabolism and inflammatory signaling to protect the retina

Albino individuals are clinically recognized to exhibit heightened susceptibility to light-induced retinal injury, yet the cellular and metabolic mechanisms underlying this vulnerability remain poorly defined. Here, we investigated whether retinal pigment epithelium (RPE) pigmentation governs mitochondrial structure, metabolism, and inflammatory responses that ultimately determine retinal resilience to blue light stress. Using pigmented (C57BL/6J) and albino (Balb/c) mice, we demonstrate that albino animals exhibit markedly increased retinal phototoxicity following blue light exposure, manifested by fundus lesions, outer nuclear layer (ONL) disruption, and structural degeneration evident by OCT. Primary RPE cultures derived from albino mice exhibited profound difference in mitochondrial morphology, characterized by increased mitochondrial number, reduced size, and enhanced fragmentation, accompanied by elevated mitochondrial DNA copy number. These structural changes correlated with transcriptional skewing toward mitochondrial fission (increased Drp1) and suppression of mitochondrial fusion (Mfn1, Mfn2, OPA1). Functionally, albino and depigmented RPE displayed impaired oxidative phosphorylation, reduced ATP production, and diminished reliance on mitochondrial pyruvate carrier (MPC)-dependent metabolism. In parallel, albino RPE demonstrated cell-cycle accumulation at G2/M and heightened basal and blue light-induced secretion of pro-inflammatory cytokines, particularly IFN-{beta}1, IL-6, and TNF-. Importantly, exogenous melanin supplementation partially restored mitochondrial fusion gene expression, pyruvate-dependent respiration, and inflammatory restraint. Together, these findings identify melanin as a critical regulator of RPE mitochondrial architecture, metabolic substrate utilization, and inflammatory signaling, providing a mechanistic framework to explain enhanced photo-vulnerability in the albino retina. These insights establish pigmentation-dependent mitochondrial metabolism as a determinant of retinal resilience and suggest mitochondrial bioenergetics as a therapeutic target.

cell biology↗