Biology subjects

Hurley, J. B.

Publications and source records attributed to Hurley, J. B..

18 recordsLinked to original sources

bioRxiv2026

Chronic Hypoxic Signalling Reprograms Metabolism and Alters Redox and Lipid Homeostasis in Rod Photoreceptors

Photoreceptors are among the most metabolically active cells in the retina and are therefore highly sensitive to fluctuations in oxygen availability. Age-related tissue changes in the eye affect oxygen delivery to the outer retina, which may result in hypoxic stress within photoreceptors and can contribute to disease development and retinal degeneration. To investigate how chronic hypoxic signalling affects photoreceptor metabolism, we examined a rod-specific Vhl knockout mouse (Rod{Delta}Vhl), in which constitutive HIF activation mimics the molecular response to hypoxia. Combining a cell-type-enriched multi-omics approach with metabolic flux analysis, we identified an early metabolic response in the retina of Rod{Delta}Vhl mice prior to degeneration. This response was characterized by a shift towards an oxidative redox environment indicated by a decrease in nucleotide precursors and an increased antioxidant response. While steady-state glycolytic flux remained unchanged, the dynamic 13C-glucose tracing revealed accelerated carbon flow through the three-carbon glycolytic intermediates, indicating a carbon rerouting. Outer segment lipidomics revealed selective remodelling of phosphatidylcholine and phosphatidylethanolamine species toward more oxidation-resistant and elongated acyl chains, supported by early gene upregulation of essential enzymes involved in fatty acid elongation, desaturation and oxidation. Together, these findings indicate a coordinated shift in metabolic and lipid pathways in photoreceptors under chronic hypoxic stress, consistent with an adaptive response that may help preserve outer segment integrity and improve stress resilience.

neuroscience↗

bioRxiv2026

Nutrient microenvironments reprogram RPE metabolism

Induced pluripotent stem cell-derived retinal pigment epithelium (iPSC RPE) has become a widely used model for studying the mechanisms of age-related macular degeneration (AMD). However, the nutrient composition of currently used RPE culture media is highly variable, posing a major challenge to reproducibility in RPE metabolism and phenotype. We systematically investigate how six distinct nutrient microenvironments shape RPE phenotype, function and metabolism in both iPSC RPE and fetal RPE (fRPE). These included MEM, DMEM-HG/F12 basal media, physiological human plasma-like medium (HPLM) supplemented with FBS or B27, and X-VIVO 10. Although canonical RPE markers were expressed across all conditions, B27 supplementation and X-VIVO 10 increased RPE cell size, hexagonality, and transepithelial resistance. Culture in HPLM+FBS induced accumulation of lipid droplets and sub-RPE deposits, whereas X-VIVO 10 resulted in the formation of large intracellular vacuoles. B27 supplementation enhanced basal respiration, while X-VIVO 10 increased glycolytic capacity. Amino acid consumption was broadly conserved across media types, including complete depletion of proline in all conditions by 48 hours; however, lipid and nucleotide metabolism varied substantially between conditions. Notably, B27 supplementation in specific media types reversed the net direction of several metabolites, with creatine, serine and taurine shifting from consumption to production, while riboflavin and guanine shifted from production to consumption. These findings establish the nutrient environment as a key determinant of RPE phenotype, function and metabolism. Our work provides a valuable resource for media selection and interpretation of cellular and metabolic phenotypes relevant to RPE disease modeling.

cell biology↗

bioRxiv2024

Reassessing Retinal Pigment Epithelial Ketogenesis: Enzymatic Assays for Ketone Body Levels Provide Inaccurate Results

The retinal pigment epithelium (RPE) is omnivorous and can utilize a wide range of substrates for oxidative phosphorylation. Certain tissues with high mitochondrial metabolic load are capable of ketogenesis, a biochemical pathway that consolidates acetyl-CoA into ketone bodies. Earlier work demonstrated that the RPE expresses the rate-limiting enzyme for ketogenesis, 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), and that the RPE indeed produces ketone bodies, including beta-hydroxybutyrate ({beta}-HB). Prior work, based on detecting {beta}-HB via enzymatic assays, suggested that differentiated cultures of primary RPE preferentially export {beta}-HB across the apical membrane. Here, we compare the accuracy of measuring {beta}-HB by enzymatic assay kits to mass spectrometry analysis. We found that commercial kits lack the sensitivity to accurately measure the levels of {beta}-HB in RPE cultures and are prone to artifact. Using mass spectrometry, we found that while RPE cultures secrete {beta}-HB, they do so equally to both apical and basal sides. We also find RPE is capable of consuming {beta}-HB as levels rise. Using isotopically labeled glucose, amino acid, and fatty acid tracers, we found that carbons from both fatty acids and ketogenic amino acids, but not from glucose, produce {beta}-HB. Altogether, we substantiate {beta}-HB secretion in RPE but find that the secretion is equal apically and basally, RPE {beta}-HB can derive from ketogenic amino acids or fatty acids, and accurate {beta}-HB assessment requires mass spectrometric analysis.

cell biology↗

bioRxiv2023

Acetyl-CoA carboxylase inhibition increases RPE cell fatty acid oxidation and limits apolipoprotein efflux

PurposeIn age-related macular degeneration (AMD) and Sorsbys fundus dystrophy (SFD), lipid-rich deposits known as drusen accumulate under the retinal pigment epithelium (RPE). Drusen may contribute to photoreceptor and RPE degeneration in AMD and SFD. We hypothesize that stimulating {beta}-oxidation in RPE will reduce drusen accumulation. Inhibitors of acetyl-CoA carboxylase (ACC) stimulate {beta}-oxidation and diminish lipid accumulation in fatty liver disease. In this report we test the hypothesis that an ACC inhibitor, Firsocostat, limits the accumulation of lipid deposits in cultured RPE cells. MethodsWe probed metabolism and cellular function in mouse RPE-choroid, human fetal- derived RPE cells, and induced pluripotent stem cell-derived RPE cells. We used 13C6-glucose and 13C16-palmitate to determine the effects of Firsocostat on glycolytic, Krebs cycle, and fatty acid metabolism. 13C labeling of metabolites in these pathways were analyzed using gas chromatography-linked mass spectrometry. We quantified ApoE and VEGF release using enzyme-linked immunosorbent assays. Immunostaining of sectioned RPE was used to visualize ApoE deposits. RPE function was assessed by measuring the trans-epithelial electrical resistance (TEER). ResultsACC inhibition with Firsocostat increases fatty acid oxidation and remodels lipid composition, glycolytic metabolism, lipoprotein release, and enhances TEER. When human serum is used to induce sub-RPE lipoprotein accumulation, fewer lipoproteins accumulate with Firsocostat. In a culture model of Sorsbys fundus dystrophy, Firsocostat also stimulates fatty acid oxidation, improves morphology, and increases TEER. ConclusionsFirsocostat remodels intracellular metabolism and improves RPE resilience to serum-induced lipid deposition. This effect of ACC inhibition suggests that it could be an effective strategy for diminishing drusen accumulation in the eyes of patients with AMD.

biochemistry↗

bioRxiv2023

Proline provides a nitrogen source in the retinal pigment epithelium to synthesize and export amino acids for the neural retina

It is known that metabolic defects in the retinal pigment epithelium (RPE) can cause degeneration of its neighboring photoreceptors in the retina, leading to retinal degenerative diseases such as age-related macular degeneration. However, how RPE metabolism supports the health of the neural retina remains unclear. The retina requires exogenous nitrogen sources for protein synthesis, neurotransmission, and energy metabolism. Using 15N tracing coupled with mass spectrometry, we found human RPE can utilize the nitrogen in proline to produce and export 13 amino acids, including glutamate, aspartate, glutamine, alanine and serine. Similarly, we found this proline nitrogen utilization in the mouse RPE/Cho but not in the neural retina of explant cultures. Co-culture of human RPE with the retina showed that the retina can take up the amino acids, especially glutamate, aspartate and glutamine, generated from proline nitrogen in the RPE. Intravenous delivery of 15N proline in vivo demonstrated 15N-derived amino acids appear earlier in the RPE before the retina. We also found proline dehydrogenase (PRODH), the key enzyme in proline catabolism, is highly enriched in the RPE but not the retina. The deletion of PRODH blocks proline nitrogen utilization in RPE and the import of proline nitrogen-derived amino acids in the retina. Our findings highlight the importance of RPE metabolism in supporting nitrogen sources for the retina, providing insight into understanding the mechanisms of the retinal metabolic ecosystem and RPE-initiated retinal degenerative diseases.

biochemistry↗

bioRxiv2023

The Circulation of Metabolites in the Outer Retina

Photoreceptors in the retina of a vertebrates eye are supported by a tissue adjacent to the retina, the retinal pigment epithelium (RPE). The RPE delivers glucose to the outer retina, consumes photoreceptor outer segments discs, and regenerates 11-cis-retinal. Here we address the question of whether photoreceptors also provide metabolic support to the RPE. We use complementary approaches and animal models to show that glucose is the primary fuel for the retina, that photoreceptors are the primary cell type in the retina to consume glucose, and that lactate derived from photoreceptor glucose consumption is transported to and catabolized by the RPE. These data rigorously support and extend the concept of a metabolic ecosystem between photoreceptors and RPE.

biochemistry↗

bioRxiv2023

Medium depth influences O2 availability and metabolism in cultured RPE cells

Structured AbstractO_ST_ABSPurposeC_ST_ABSRPE oxidative metabolism is critical for normal retinal function and is often studied in cell culture systems. Here, we show that conventional culture media volumes dramatically impact O2 availability, limiting oxidative metabolism. We suggest optimal conditions to ensure cultured RPE is in a normoxic environment permissive to oxidative metabolism. MethodsWe altered the availability of O2 to human primary RPE cultures directly via a hypoxia chamber or indirectly via the amount of medium over cells. We measured oxygen consumption rates (OCR), glucose consumption, lactate production, 13C6-glucose flux, hypoxia inducible factor (HIF-1) stability, intracellular lipid droplets after a lipid challenge, trans-epithelial electrical resistance, cell morphology, and pigmentation. ResultsMedium volumes commonly employed during RPE culture limit diffusion of O2 to cells, triggering hypoxia, activating HIF-1, limiting OCR, and dramatically altering cell metabolism, with only minor effects on typical markers of RPE health. Media volume effects on O2 availability decrease acetyl-CoA utilization, increase glycolysis, and alter the size and number of intracellular lipid droplets under lipid-rich conditions. ConclusionsDespite having little impact on visible and typical markers of RPE culture health, media volume dramatically affects RPE physiology "under the hood". As RPE-centric diseases like age-related macular degeneration (AMD) involve oxidative metabolism, RPE cultures need to be optimized to study such diseases. We provide guidelines for optimal RPE culture volumes that balance ample nutrient availability from larger media volumes with adequate O2 availability seen with smaller media volumes.

cell biology↗

bioRxiv2022

Multi-tissue landscape of somatic mtDNA mutations indicates tissue specific accumulation and removal in aging

Accumulation of somatic mutations in the mitochondrial genome (mtDNA) during aging has long been proposed as a possible mechanism of mitochondrial and tissue dysfunction. A thorough characterization of age-associated mtDNA somatic mutations has been hampered by the limited ability to detect low frequency mutations. Here, we used Duplex Sequencing on eight tissues of an aged mouse cohort to detect >89,000 independent somatic mtDNA mutations and show significant tissue-specific increases during aging across all tissues examined which did not correlate with mitochondrial content and tissue function. G[->]A/C[->]T substitutions, indicative of replication errors and/or cytidine deamination, were the predominant mutation type across all tissues and increased with age, whereas G[->]T/C[->]A substitutions, indicative of oxidative damage, were the second most common mutation type, but did not increase with age regardless of tissue. We also show that clonal expansions of mtDNA mutations with age is tissue and mutation type dependent. Unexpectedly, mutations associated with oxidative damage rarely formed clones in any tissue and were significantly reduced in the hearts and kidneys of aged mice treated at late age with Elamipretide or nicotinamide mononucleotide. Thus, the lack of accumulation of oxidative damage-linked mutations with age indicates a life-long dynamic clearance of either the oxidative lesions or mtDNA genomes harboring oxidative damage.

genomics↗

bioRxiv2021

Monocarboxylate Transporter 1 (MCT1) mediates succinate export in the retina

PurposeSuccinate is exported by the retina and imported by eyecup tissue. The transporter(s) mediating this process have not yet been identified. Recent studies showed that Monocarboxylate Transporter 1 (MCT1) can transport succinate across plasma membranes in cardiac and skeletal muscle. Retina and retinal pigment epithelium (RPE) both express multiple MCT isoforms including MCT1. We tested the hypothesis that MCTs facilitate retinal succinate export and RPE succinate import. MethodsWe assessed retinal succinate export and eyecup succinate import in short term ex vivo culture using gas chromatography-mass spectrometry. We test the dependence of succinate export and import on pH, proton ionophores, conventional MCT substrates, and the MCT inhibitors AZD3965, AR-C155858, and diclofenac. ResultsSuccinate exits retinal tissue through MCT1 but does not enter RPE through MCT1 or any other MCT. Intracellular succinate levels are a contributing factor that determines if an MCT1-expressing tissue will export succinate. ConclusionsMCT1 facilitates export of succinate from retinas. An unidentified, non-MCT transporter facilitates import of succinate into RPE.

biochemistry↗

bioRxiv2021

A mutational gradient drives somatic mutation accumulation in mitochondrial DNA and influences germline polymorphisms and genome composition

BackgroundMutations in the mitochondrial genome (mtDNA) can cause devastating maternally inherited diseases, while the accumulation of somatic mtDNA mutations is linked to common diseases of aging. Although mtDNA mutations impact human health, the process(es) that give rise to these mutations are unclear and are under considerable debate. We analyzed the distribution of naturally occurring somatic mutations across the mouse and human mtDNA obtained by Duplex Sequencing to provide clues to the mechanism by which de novo mutations arise as well as how the genome is replicated. ResultsWe observe two distinct mutational gradients in G[->]A and T[->]C transitions, but not their complements, that are delimited by the light-strand origin and the control region (CR). The gradients increase with age and are lost in the absence of DNA polymerase {gamma} proofreading activity. A nearly identical pattern is present in human mtDNA somatic mutations. The distribution of mtDNA single nucleotide polymorphisms (SNPs) in the human population and genome base composition across >3,000 vertebrate species mirror this gradient pattern, pointing to evolutionary conservation of this phenomenon. Lastly, high-resolution analysis of the mtDNA control region highlights mutational hotspots and cold-spots that strongly align with important regulatory regions. ConclusionsCollectively, these patterns support an asymmetric strand-displacement mechanism with key regulatory structures in the CR and argue against alternative replication models. The mutational gradient is a fundamental consequence of mtDNA replication that drives somatic mutation accumulation and influences inherited polymorphisms and, over evolutionary timescales, genome composition.

genomics↗

bioRxiv2021

Metabolic function in aging retina and retinal pigment epithelium remains robust despite vision loss

PurposeCharacterize how metabolic function in the murine retina and retinal pigment epithelium-choroid-sclera (eyecup) complex is impacted by natural aging. MethodsWe examined scotopic and photopic visual function of young (3-6 months) and aged (23-26 months) C57Bl/6J mice using electroretinograms (ERGs). Metabolic changes in retina and eyecup explants were characterized by measuring uptake and usage of U-13C-glucose or U-13C-glutamine at different timepoints by gas chromatography-mass spectrometry (GC-MS), measuring oxygen consumption rate (OCR) using a perifusion apparatus, and determining ATP levels with a bioluminescence assay. ResultsScotopic and photopic ERG responses declined in aged mice. Glucose metabolism, glutamine metabolism, OCR, and ATP pools in retinal explants were mostly unaffected by the age of the mouse. In eyecups, glutamine usage in the Krebs Cycle decreased while glucose metabolism, OCR, and ATP pools remained stable. ConclusionsThe ex vivo approach in our study to examine aging glucose and glutamine metabolism in retina and RPE showed negligible impact of age on retina and an impairment of glutamine anaplerosis in eyecups. The surprising metabolic stability of these tissues ex vivo suggests age-related metabolic alterations in these tissues may not be intrinsic. Future experiments should focus on determining whether external factors including nutrient supply, oxygen availability, or other structural changes influence ocular metabolism in vivo.

biochemistry↗

bioRxiv2021

Fluidics System for Resolving Concentration-Dependent Effects of Dissolved Gases on Tissue Metabolism

Oxygen (O2) and other dissolved gases such as the gasotransmitters H2S, CO and NO affect cell metabolism and function. To evaluate effects of dissolved gases on processes in tissue, we developed a fluidics system that controls dissolved gases while simultaneously measuring parameters of electron transport, metabolism and secretory function. We use pancreatic islets, retina and liver to highlight its ability to assess effects of O2 and H2S. Protocols aimed at emulating hypoxia-reperfusion conditions resolved a previously unrecognized transient spike in O2 consumption rate (OCR) following replenishment of O2, and tissue-specific recovery of OCR following hypoxia. The system revealed both inhibitory and stimulatory effects of H2S on insulin secretion rate from isolated islets. The unique ability of this new system to quantify metabolic state and cell function in response to precise changes in dissolved gases provides a powerful platform for cell physiologists to study a wide range of disease states.

cell biology↗

bioRxiv2021

Succinate is Broadly Tissue-Permeant and Uncouples Mitochondrial Respiration from ATP Synthesis

Succinate is central in energy metabolism. It is thought to be made and consumed within mitochondria, and not to cross the plasma membrane. Contrary to the canonical role of succinate, it is produced in the retina and released into the extracellular milleau. It is unknown how this affects adjacent retinal pigment epithelium, within eyecup tissue. By measuring consumption of 13C4-succinate and O2 we probe metabolism of the eyecup, we find robust succinate consumption by eyecup but not retina tissue. Succinate-dependant stimulation of eyecup respiration is oligomycin resistant; indicating that in eyecup tissue succinate uncouples mitochondrial ATP synthesis from respiration.

biochemistry↗

bioRxiv2021

Extracellular Matrix Dysfunction in Sorsby Patient-Derived Retinal Pigment Epithelium

Sorsby Fundus Dystrophy (SFD) is a rare form of macular degeneration that is clinically similar to age-related macular degeneration (AMD), and a histologic hallmark of SFD is a thick layer of extracellular deposits beneath the retinal pigment epithelium (RPE). Previous studies of SFD patient-induced pluripotent stem cell (iPSC) derived RPE differ as to whether these cultures recapitulate this key clinical feature by forming increased drusenoid deposits. The primary purpose of this study is to examine whether SFD patient-derived iPSC-RPE form basal deposits similar to what is found in affected family member SFD globes and to determine whether SFD iPSC RPE may be more oxidatively stressed. We performed a careful comparison of iPSC RPE from three control individuals, multiple iPSC clones from two SFD patients iPSC RPE, and post-mortem eyes of affected SFD family members. We also examined the effect of CRISPR-Cas9 gene correction of the S204C TIMP3 mutation on RPE phenotype. Finally, targeted metabolomics analysis with liquid chromatography and mass spectrometry analysis and stable isotope-labeled metabolite analysis was performed to determine whether SFD RPE are more oxidatively stressed. We found that SFD iPSC-RPE formed significantly more sub-RPE deposits ([~]6-90 m in height) compared to control RPE at 8 weeks. These deposits were similar in composition to the basal laminar drusen found in SFD family member globes by immunofluorescence staining and TEM imaging. S204C TIMP3 correction by CRISPR-Cas9 gene editing in SFD iPSC RPE cells resulted in significantly reduced basal laminar and sub-RPE calcium deposits. We detected a [~]18-fold increase in TIMP3 accumulation in the extracellular matrix (ECM) of SFD RPE, and targeted metabolomics showed that intracellular 4-hydroxyproline, a major breakdown product of collagen, is significantly elevated in SFD RPE, suggesting increased ECM turnover. Finally, SFD RPE cells have decreased intracellular reduced glutathione and were found to be more vulnerable to oxidative stress. Our findings suggest that elements of SFD pathology can be demonstrated in culture which may lead to insights into disease mechanisms.

cell biology↗

bioRxiv2020

Non-photopic and photopic visual cycles differentially regulate immediate, early and late-phases of cone photoreceptor-mediated vision

Cone photoreceptors in the retina enable vision over a wide range of light intensities. However, the processes enabling cone vision in bright light (i.e. photopic vision) are not adequately understood. Chromophore regeneration of cone photopigments may require the retinal pigment epithelium (RPE) and/or retinal Muller glia. In the RPE, isomerization of all-trans-retinyl esters (atRE) to 11-cis-retinol (11cROL) is mediated by the retinoid isomerohydrolase Rpe65. An alternative retinoid isomerase, dihydroceramide desaturase-1 (DES1), is expressed in RPE and Muller cells. The retinol-isomerase activities of Rpe65 and Des1 are inhibited by emixustat and fenretinide, respectively. Here, we tested the effects of these visual cycle inhibitors on immediate, early and late phases of cone photopic vision. In zebrafish larvae raised under cyclic light conditions, fenretinide impaired late cone photopic vision, whereas emixustat-treated zebrafish unexpectedly had normal vision. In contrast, emixustat-treated larvae raised under extensive dark-adaption displayed significantly attenuated immediate photopic vision concomitantly with significantly reduced 11-cis-retinaldehyde (11cRAL). Following 30 minutes of light, early photopic vision recovered, despite 11cRAL levels remaining significantly reduced. Defects in immediate cone photopic vision were rescued in emixustat- or fenretinide-treated larvae following exogenous 9-cis-retinaldehyde (9cRAL) supplementation. Genetic knockout of degs1 or retinaldehyde-binding protein 1b (rlbp1b) revealed that neither are required for photopic vision in zebrafish. Our findings define the molecular and temporal requirements of the non-photopic and photopic visual cycles for mediating vision in bright light.

biochemistry↗

bioRxiv2020

Succinate can shuttle reducing power from the hypoxic retina to the O2-rich pigment epithelium.

When O2 is plentiful, the mitochondrial electron transport chain uses it as a terminal electron acceptor. However, the mammalian retina thrives within a hypoxic niche in the eye. We find that mitochondria in retinas adapt to their hypoxic environment by relying on the "reverse" succinate dehydrogenase reaction, where fumarate accepts electrons instead of O2. Reverse succinate dehydrogenase activity produces succinate and is enhanced by down-regulation of cytochrome oxidase subunits. Retinas can export the succinate to the neighboring retinal pigment epithelium/choroid complex. There, succinate stimulates O2 consumption several fold and enhances synthesis and release of malate. Malate released from the pigment epithelium can be imported into the retina, where it is converted to fumarate and again used to accept electrons in the reverse succinate dehydrogenase reaction. Our findings show how a malate/succinate shuttle can sustain these two tissues by transferring reducing power from an O2-poor tissue (retina) to an O2-rich one (retinal pigment epithelium/choroid).

biochemistry↗

bioRxiv2019

Mitochondrial Ca2+ influences photoresponse recovery, metabolism, and mitochondrial localization in cone photoreceptors

Mitochondrial Ca2+ regulates key cellular processes including cytosolic Ca2+ signals, energy production, and susceptibility to apoptosis. Photoreceptors are specialized neurons that have extraordinarily high energy demands and rely on cytosolic Ca2+ signals for light adaptation and neurotransmission. Here we show that unlike other neurons zebrafish cone photoreceptors express low levels of the mitochondrial Ca2+ uniporter (MCU), the channel that allows mitochondrial Ca2+ entry. To determine why MCU expression is kept low, we overexpressed MCU specifically in cones. This increases mitochondrial [Ca2+], causes faster cytosolic Ca2+ clearance, and accelerates photoresponse recovery. Moreover, flux through the citric acid cycle increases despite dramatic changes in mitochondrial ultrastructure and localization. Remarkably, cones survive this ongoing stress until late adulthood. Our findings demonstrate the importance of tuning mitochondrial Ca2+ influx to modulate physiological and metabolic processes and reveal a novel directed movement of abnormal mitochondria in photoreceptors.

cell biology↗

bioRxiv2017

Biochemical Adaptations Of The Retina And Retinal Pigment Epithelium Support A Metabolic Ecosystem In The Vertebrate Eye

Here we report multiple lines of evidence for a comprehensive model for retinal energy metabolism. Metabolic flux, locations of key enzymes and our finding that glucose enters the neural retina almost entirely through photoreceptors support a conceptually new model for retinal metabolism. In this model, glucose from the choroidal blood supply passes through the retinal pigment epithelium to the retina where photoreceptors convert it to lactate. Photoreceptors then export the lactate as fuel for the retinal pigment epithelium and for neighboring Muller glial cells. A key feature of this model is that aerobic glycolysis in photoreceptors produces lactate to suppress glycolysis in the neighboring retinal pigment epithelium. That enhances the flow of glucose to the retina by minimizing consumption of glucose within the retinal pigment epithelium. This framework for metabolic relationships in retina provides new insights into the underlying causes of retinal disease, age-related vision loss and metabolism-based therapies.

biochemistry↗