Lipofuscin Research Articles

Antioxidant and Antiaging Activity of Houttuynia cordata Thunb. Ethyl Acetate Fraction in Caenorhabditis elegans

Background/Objectives: In aerobic organisms, such as humans, oxygen radicals are inevitably produced. To counteract oxidation, the body generates antioxidant substances that suppress free radicals. However, levels of reactive oxygen species (ROS) increase due to aging and lifestyle factors, leading to exposure to various diseases. While synthetic antioxidants offer advantages like high stability, low cost, and availability, their safety remains controversial. This study aimed to investigate the antioxidant and antiaging activities of Houttuynia cordata (HC), which is rich in flavonoids and has excellent antioxidant properties, using Caenorhabditis elegans as a model. Methods: Extraction and fractionation of HC were performed to evaluate antioxidant activities (DPPH, ABTS, superoxide radical scavenging activity) and antiaging effects (lifespan). The ethyl acetate fraction (EAF) with the highest activity was selected for further investigation. Results: The EAF of HC exhibited high levels of polyphenols and flavonoids, presenting the highest DPPH, ABTS, and superoxide radical scavenging activities. This fraction increased the activity of antioxidant enzymes in nematodes in a concentration-dependent manner and provided resistance to oxidative stress, reducing ROS accumulation. Additionally, the fraction enhanced the lifespan of nematodes, improved resistance to heat stress, increased survival rates, and decreased the accumulation of aging pigments (lipofuscin). The expression of daf-2, daf-16, and sir-2.1, proteins directly involved in nematode aging, was confirmed. Liquid chromatography/tandem mass spectrometry identified quercitrin in the HC extract, which may contribute to its antioxidant and antiaging effects. Conclusions: The EAF of HC demonstrates significant potential for influencing antioxidant and antiaging, as evidenced by functional investigations using C. elegans.

Interaction between imidacloprid residues in maize rhizospheric soil and soil nematode community

Although imidacloprid has been shown to present potential risks to non-target invertebrates and vertebrates, researches exploring this risk from the perspective of the underground ecosystem remains incomplete. In this study, we determined that the presence of imidacloprid significantly reduced the abundance and diversity of soil nematodes in maize rhizospheric soil. Furthermore, imidacloprid also exerted negative effects on the body length, reproduction, locomotion, lipid accumulation, lipofuscin accumulation, and acetylcholinesterase activity in the model organism Caenorhabditis elegans. These toxic phenotypes are correlated with the upregulation of fat-2, fat-6, hsp-16.41, and hsp-16.2, along with the downregulation of ace-1, ace-2, and ace-3. In response to these toxic effects of imidacloprid, nematodes also developed corresponding adaptive mechanisms. UPLC-MS/MS analysis revealed that nematodes could convert imidacloprid to imidacloprid-guanidine and imidacloprid-urea to reduce the toxicity of imidacloprid. Moreover, C. elegans and Meloidogyne incognita exhibited repellent behavior towards imidacloprid-treated area, even the concentration of imidacloprid is only 0.4 μg/mL. This study revealed the interaction between imidacloprid and nematodes, providing a basis for understanding the potential risks of non-target soil nematodes after application of imidacloprid in sustainable agriculture and the resistance mechanism of nematodes to nematocidal pesticide.

The age pigment lipofuscin causes oxidative stress, lysosomal dysfunction, and pyroptotic cell death

Accumulation of the age pigment lipofuscin represents a ubiquitous hallmark of the aging process. However, our knowledge about cellular effects of lipofuscin accumulation is potentially flawed, because previous research mainly utilized highly artificial methods of lipofuscin generation. In order to address this tremendous problem, we developed a convenient protocol for isolation of authentic lipofuscin from human and equine cardiac tissue in high purity and quantity. Isolated lipofuscin aggregates contained elevated concentrations of proline and metals such as calcium or iron. The material was readily incorporated by fibroblasts and caused cell death at low concentrations (LC50 = 5.0 μg/mL) via a pyroptosis-like pathway. Lipofuscin boosted mitochondrial ROS production and caused lysosomal dysfunction by lysosomal membrane permeabilization leading to reduced lysosome quantity and impaired cathepsin D activity. In conclusion, this is the first study utilizing authentic lipofuscin to experimentally validate the concept of the lysosomal-mitochondrial axis theory of aging and cell death.

Unraveling Marfan hearts: ultrastructural evidence for myocardial remodeling and cardiomyopathy

Abstract Background Despite improved life expectancy for patients with Marfan syndrome (MFS), significant morbidity and mortality persist. Although primarily attributed to aortic dissection and rupture, recent studies highlight the emerging role of arrhythmias and heart failure as additional contributors to morbidity and mortality in MFS. While severe valvular heart disease is an established cause of heart failure, there is a growing recognition of primary cardiomyopathy in patients with MFS. The mechanisms underlying cardiomyopathy in MFS remain poorly understood. Purpose This study aimed to reveal insights into the ultrastructural myocardial architecture in patients with MFS, thereby elucidating the role of cardiomyopathy in MFS. Methods This study enrolled 44 patients who underwent cardiac surgery at 2 centers (Marfan syndrome patients n=27 (MFS), ascending thoracic aortic aneurysm repair patients n=5 (non-MFS), patients post-orthotopic heart transplant n=12 (controls)). Myocardial biopsy samples were subjected to histopathological analysis using transmission electron microscopy and conventional histology. Results Conventional histological analysis revealed subtle abnormalities in the cardiomyocyte morphology of MFS patients, compared to non-MFS and controls. Overall, a slight increase in interstitial fibrosis and mild myocyte hypertrophy were observed in MFS patients. Ultrastructural examination of both MFS and non-MFS patients revealed significant structural remodeling and degenerative changes in the myocardium. These changes included: extensive myofibril lysis, compromised cell membrane integrity and nuclear chromatin condensation. Degenerative lesions were often accompanied by cytoplasmic debris, lysosomal residual bodies, autophagic vacuoles, and severe mitochondrial pathology. Dense accumulation of glycogen granules and lipofuscin was evident in areas of focal myofibril lysis. Notably, only MFS patients exhibited recruitment of granulocytes, including mast cells, eosinophils and neutrophils. A subset of MFS patients displayed advanced stages of myocardial degeneration. However, these changes did not correlate with clinical myocardial failure. Conclusions To the best of our knowledge, this study represents the first evidence of ultrastructural changes in the myocardium of patients with MFS. Our data indicate various degenerative changes in the myocardial architecture, including structural and metabolic myocardial remodeling, along with inflammatory cell infiltration. We believe that our findings of ultrastructural lesions reflect the complexity of myocardial disease in MFS and emphasize the importance of careful surveillance for cardiomyopathy in MFS patients. Further studies are warranted to confirm whether the observed granulocyte influx is specific to MFS and to clarify its role in MFS myocardial disease pathophysiology.Graphical abstract

Growth differentiation factor 11 alleviates oxidative stress-induced senescence of endothelial progenitor cells via activating autophagy

BackgroundStem cell transplantation has been regarded as a promising therapeutic strategy for myocardial regeneration after myocardial infarction (MI). However, the survival and differentiation of the transplanted stem cells in the hostile ischaemic and inflammatory microenvironment are poor. Recent studies have focused on enhancing the survival and differentiation of the stem cells, while strategies to suppress the senescence of the transplanted stem cells is unknown. Therefore, we investigated the effect of growth differentiation factor 11 (GDF11) on attenuating oxidative stress-induced senescence in the engrafted endothelial progenitor cells (EPCs).MethodsRat models of oxidative stress were established by hydrogen peroxide conditioning. Oxidative stress-induced senescence was assessed through senescence-associated β-galactosidase expression and lipofuscin accumulation. The effects of GDF11 treatment on senescence and autophagy of EPCs were evaluated 345, while improvement of myocardial regeneration, neovascularization and cardiac function were examined following transplantation of the self-assembling peptide (SAP) loaded EPCs and GDF11 in the rat MI models.ResultsFollowing hydrogen peroxide conditioning, the level of ROS in EPCs decreased significantly upon treatment with GDF11. This resulted in reduction in the senescent cells and lipofuscin particles, as well as the damaged mitochondria and rough endoplasmic reticula. Concurrently, there was a significant increase in LC3-II expression, LC3-positive puncta and the presence of autophagic ultrastructures were increased significantly. The formulated SAP effectively adhered to EPCs and sustained the release of GDF11. Transplantation of SAP-loaded EPCs and GDF11 into the ischaemic abdominal pouch or myocardium resulted in a decreased number of the senescent EPCs. At four weeks after transplantation into the myocardium, neovascularization and myocardial regeneration were enhanced, reverse myocardial remodeling was attenuated, and cardiac function was improved effectively.ConclusionsThis study provides novel evidence suggesting that oxidative stress could induce senescence of the transplanted EPCs in the ischemic myocardium. GDF11 demonstrates the ability to mitigate oxidative stress-induced senescence in the transplanted EPCs within the myocardium by activating autophagy.

Stress resistance, antiaging, and neuroprotective activities of baicalein 5,6-dimethyl ether and Alnus rugosa extract in Caenorhabditis elegans model.

The leaf extract of Alnus rugosa (AR) together with the isolated compound baicalein 5,6-dimethyl ether (BME) were investigated for their antioxidant, radical scavenging, antiaging, and neuroprotective properties using the Caenorhabditis elegans model. The stress resistance and antiaging potential of AR and BME were assessed in wild-type N2 and transgenic C. elegans strains CF1553, TJ356, and BA17. Transgenic CL4176 expressing the human amyloid-beta peptide (Aβ) was used as a model for Aβ toxicity, whereas transgenic AM141 expressing polyQ aggregates was employed as a model for Huntington's disease. An in silico molecular docking study using Discovery Studio 4.5 was performed to elucidate the putative binding mode of BME to the active sites of Daf-2 protein, involved in longevity and oxidative stress resistance in C. elegans. BME and AR significantly delayed the appearance of oxidative stress markers in wild-type N2 and transgenic strains TJ356 and CF1553, affecting the DAF-16/FOXO transcription factor subcellular distribution and inducing expression of the sod-3 antioxidative gene. Pretreatment with AR significantly reduced the aging marker lipofuscin accumulation in BA17 worms, its effect was greater than that of epigallocatechin gallate, suggesting a potential antiaging effect. Neuroprotective effects of AR and BME were confirmed in AM141 transgenic worms, inducing a significant reduction in the score of polyQ40::GFP aggregates. Moreover, BME (25 µg/mL) resulted in a significant delay in Aβ-induced paralysis in CL4176 worms. In silico molecular modeling revealed that BME exhibited good fitting scores within the active sites of the Daf-2 protein. AR and BME exert beneficial effects in the modulation of age-related markers and attenuation of neurotoxicity in neurodegenerative disorders. Hence, AR and BME could be recognized as promising antioxidant and neuroprotective natural drug candidates that could be included in neuro-nutraceuticals.

Zein nanoparticles extend lifespan in C. elegans and SAMP8 mice

Empty zein nanoparticles (NP) have been shown to lower glycemia in rats by stimulating the secretion of endogenous GLP-1. This study evaluated the effect of these nanoparticles on the lifespan of two animal models: C. elegans fed with a glucose-rich diet and the senescence accelerated mouse-prone 8 (SAMP8 mice). In C. elegans, NP increased the mean lifespan of worms by 7 days (from 17.1 for control to 24.5 days). This observation was in line with the observed significant reductions of glucose and fat contents, lipofuscin accumulation, and ROS expression. Furthermore, NP supplementation led to an upregulation of the expression of daf-16 and skn-1 genes. DAF-16 (orthologue of the FOXO family) and SKN-1 (orthologue of mammalian Nrf/CNC proteins) are implicated in activating detoxification mechanisms against oxidative damage. In SAMP8, oral administration of NP also extended the mean lifespan of mice (by 28 % compared to controls), corroborating the protective effect of these nanoparticles.

Влияние биологически активных веществ на тепловой и окислительный стресс модельных объектов Caenorhabditis elegans

Modern medicine strives to prevent age-related diseases. Oxidative stress is associated with development and progression of various diseases. Reactive oxygen species are part of vital physiological processes. High levels of reactive oxygen lead to stress and pathology whereas low ones are associated with healthy physiology. Plant-derived adaptogens demonstrate good results in stress tolerance and homeostasis. Plant materials are a pharmacologically optimal source of chemical compounds to treat various diseases, including those caused by oxidative stress. The research featured biologically active substances isolated from extracts of callus, suspension, and root cultures of medicinal plants. Baicalin and trans-cinnamic acid were obtained from Scutellaria baicalensis while ursolic acid came from Thymus vulgaris. The biologically active substances were tested for neuroprotective properties, as well as for the impact on the expression of SOD-3 and HSP-16.2. Caenorhabditis elegans served as a model to study the accumulation of carbonylated proteins and lipofuscin. The neuroprotective activity of all tested substances decreased as their concentration fell from 200 to 10 μmol/L. C. elegans proved more resistant to thermal stress if pretreated with the biologically active substances. In response to thermal stress, nematodes expressed SOD-3 more actively than HSP-16.2. At 100 μmol/L, the biologically active substances could reduce the level of carbonylated proteins. Ursolic acid was especially effective against protein carbonylation and lipofuscin accumulation in all concentrations. Baicalin, trans-cinnamic acid, and ursolic acid made it possible to reduce oxidative and thermal stress, thus demonstrating good prospects for further studies as part of adaptogenic prepa rations.

Aberrant Lipid Metabolism and Complement Activation in Age-Related Macular Degeneration.

Age-related macular degeneration (AMD) stands as a leading cause of severe visual impairment and blindness among the elderly globally. As a multifactorial disease, AMD's pathogenesis is influenced by genetic, environmental, and age-related factors, with lipid metabolism abnormalities and complement system dysregulation playing critical roles. This review delves into recent advancements in understanding the intricate interaction between these two crucial pathways, highlighting their contribution to the disease's progression through chronic inflammation, drusen formation, and retinal pigment epithelium dysfunction. Importantly, emerging evidence points to dysregulated lipid profiles, particularly alterations in high-density lipoprotein levels, oxidized lipid deposits, and intracellular lipofuscin accumulation, as exacerbating factors that enhance complement activation and subsequently amplify tissue damage in AMD. Furthermore, genetic studies have revealed significant associations between AMD and specific genes involved in lipid transport and complement regulation, shedding light on disease susceptibility and underlying mechanisms. The review further explores the clinical implications of these findings, advocating for a novel therapeutic approach that integrates lipid metabolism modulators with complement inhibitors. By concurrently targeting these pathways, the dual-targeted approach holds promise in significantly improving outcomes for AMD patients, heralding a new horizon in AMD management and treatment.

Bisphenol S decreased lifespan and healthspan via insulin/IGF-1-like signaling-against mitochondrial stress in Caenorhabditis elegans

Bisphenol S (BPS) is widely presented and affects aging with unclear mechanisms. Here, we applied C. elegans to evaluate the effects of BPS on lifespan and healthspan and to investigate the underlying mechanisms. Both early-life and whole-life exposure to BPS at environmentally relevant doses (0.6, 6, 60 μg/L) significantly decreased lifespan, and healthspan (body bend, pharyngeal pumping, and lipofuscin accumulation). BPS exposure impaired mitochondrial structure and function, which promoted ROS production to induce oxidative stress. Furthermore, BPS increased expressions of the insulin/IGF-like signaling (IIS). Also, BPS inhibited expression of the IIS transcription factor daf-16 and its downstream anti-oxidative genes. Quercetin effectively improved BPS-induced oxidative stress byreversing BPS-regulated IIS/daf-16 pathway and anti-oxidative gene expressions. In daf-2 and daf-16 mutants, the effects of BPS and quercetin on lifespan, healthspan, oxidative stress, and anti-oxidative genes expressions were reversed, demonstrating the requirement of IIS/daf-16 for aging regulation. Molecular docking and molecular dynamics simulations confirmed the stable interaction between DAF-2 and BPS mainly via three residues (VAL1260, GLU1329, and MET1395), which was attenuated by quercetin. Our results highlighted that adverse effects of BPS on impairing lifespan and healthspan by affecting IIS/daf-16 function against mitochondrial stress, which could be inhibited by quercetin treatment. Thus, we first revealed the underlying mechanisms of BPS-induced aging and the potential treatment.

Multi-Omics Reveals the Anti-Aging Effects and Mechanisms of Bound Polyphenols from Tea Residue Dietary Fiber in 3-MCPD-Induced Caenorhabditis elegans

Previous studies have shown that bound polyphenols from tea residue dietary fiber (TBP) were novel natural food ingredient with hypoglycemic activity, but the protective effects against aging have not been fully explored. This study investigated the potential of TBP to alleviate aging in Caenorhabditis elegans induced by 3-monochloropropane-1,2-diol and elucidated the underlying mechanisms through transcriptomic and metabolomic analyses. The results demonstrated that TBP markedly prolonged the lifespan of the nematodes, improved body morphology and locomotion, and effectively reduced reactive oxygen species and lipofuscin accumulation, while enhancing antioxidant defenses. Transcriptomic and metabolomic analyses further highlighted the critical role of the Insulin/Insulin-like Growth Factor 1 (insulin/IGF-1) signaling pathway in lifespan extension, with validation provided through gene expression and fluorescent mutants. These findings underscored the significant potential of TBP to counteract the adverse effects of 3-Monochloropropane-1,2-diol (3-MCPD) and extend lifespan, thereby providing a solid theoretical foundation for developing health products and exploring novel applications.

Pentagalloyl glucose enhanced the stress resistance to delay aging process in Caenorhabditis elegans

Aging is a complex biological process characterized by gradual and irreversible functional deterioration, strongly associated with oxidative stress. Pentagalloyl glucose (PGG) has attracted increasing attention due to its potent antioxidant and anti-stress properties. This study investigated the potential of PGG to mitigate the aging process under stress in RAW 264.7 cells and Caenorhabditis elegans models. The expression of vital genes associated with stress was also measured to explain the action mechanism of PGG in C. elegans. The findings showed that PGG supplementation not only significantly enhanced the stress tolerance of RAW 264.7 cells, but also prolonged lifespan and reduced the ROS and lipofuscin accumulation in C. elegans induced by stress. Meanwhile, the improvement effect of PGG on delaying aging development was also manifested in the protection of mitochondrial function and neuronal integrity. Moreover, daf-16 nuclear translocation and sod-3 expression were significantly enhanced by PGG to delay the aging process. Mechanistically, PGG might alleviate aging by improving daf-16, sod-3, ctl-1, and gst-4 levels in the DAF-16/FOXO pathway and upregulating skn-1 and gst-4 expression in the SKN-1/Nrf2 pathway. Our study provided novel insights into the role of PGG in combating stress-induced aging.

The Interstitial Gland as a Source of Pro- or Anti-Senescent Cells during Chinchilla Rabbit Ovarian Aging.

The aging ovary in mammals leads to the reduced production of sex hormones and a deterioration in follicle quality. The interstitial gland originates from the hypertrophy of the theca cells of atretic follicles and represents an accumulative structure of the ovary that may contribute to its aging. Here, reproductive and mature rabbit ovaries are used to determine whether the interstitial gland plays a crucial role in ovarian aging. We demonstrate that, in the mature ovary, interstitial gland cells accumulate lipid droplets and show ultrastructural characteristics of lipophagy. Furthermore, they undergo modifications and present a foamy appearance, do not express the pan-leukocyte CD-45 marker, and express CYP11A1. These cells are the first to present an increase in lipofuscin accumulation. In foamy cells, the expression of p21 remains low, PCNA expression is maintained at mature ages, and their nuclei do not show positivity for H2AX. The interstitial gland shows a significant increase in lipofuscin accumulation compared with the ovaries of younger rabbits, but lipofuscin accumulation remains constant at mature ages. Surprisingly, no accumulation of cells with DNA damage is evident, and an increase in proliferative cells is observed at the age of 36 months. We suggest that the interstitial gland initially uses lipophagy to maintain steroidogenic homeostasis and prevent cellular senescence.

Toward Systemic Lipofuscin Removal.

Lipofuscin is indigestible garbage that accumulates in the autophagic vesicles and cytosol of postmitotic cells with age. Drs. Brunk and Terman postulated that lipofuscin accumulation is the main or at least a major driving factor in aging. They even posited that the evolution of memory is the reason why we get lipofuscin at all, as stable synaptic connections must be maintained over time, meaning that the somas of neurons must also remain in the same locale. In other words, they cannot dilute out their garbage over time through cell division. Mechanistically, their position certainly makes sense given that rendering a large percentage of a postmitotic cell's lysosomes useless must almost certainly negatively affect that cell and the surrounding microenvironment. It may be the case that lipofuscin accumulation is the main issue with regard to current age-related disease. Degradation in situ may be an insurmountable task currently. However, a method of systemic lipofuscin removal is discussed herein.

Erythrocyte Oxidative Status in People with Obesity: Relation to Tissue Losses, Glucose Levels, and Weight Reduction.

This study aimed to investigate the impact of reductions in various body mass components on the erythrocyte oxidative status and glycemic state of people with obesity (PWO). A total of 53 PWO followed a six-month individualized low-calorie diet with exercise, during which anthropometric, biochemical, and oxidative parameters were measured. The participants were divided into groups based on weight (W), visceral fat area (VFA), total body water (TBW), and skeletal muscle mass (SMM) losses, as well as normoglycemia (NG) and hyperglycemia (HG). Weight reduction normalized glycemia and influenced erythrocyte enzyme activity. Regardless of the tissue type lost (VFA, TBW, or SMM), glutathione peroxidase activity decreased in all groups, accompanied by an increase in glutathione reductase activity. Lipofuscin (LPS) and malondialdehyde (MDA) concentrations decreased regardless of the type of tissue lost. The α-/γ-tocopherol ratio increased in those losing >10% body weight, >15% VFA, and >5% TBW. In the NG group, compared to the HG group, there was a decrease in glutathione peroxidase and an increase in glutathione reductase, with these changes being stronger in the HG group. The LPS and MDA concentrations decreased in both groups. Significant correlations were observed between glucose reduction and changes in catalase, retinol, and α-tocopherol, as well as between VFA reduction and changes in vitamin E, L-LPS, and the activities of L-GR and L-GST. This analysis highlights the complex interactions between glucose metabolism, oxidative state, and erythrocyte membrane integrity, crucial for understanding diabetes and its management. This study shows the significant metabolic adaptability of erythrocytes in response to systemic changes induced by obesity and hyperglycemia, suggesting potential therapeutic targets to improve metabolic health in obese individuals.

Ceruloplasmin and Lipofuscin Serum Concentrations Are Associated with Presence of Hypertrophic Cardiomyopathy.

Oxidative stress reflects an imbalance between the systemic manifestation of reactive oxygen species and cells' ability to neutralize them by antioxidant systems. The role of oxidative stress in hypertrophic cardiomyopathy (HCM) is not fully understood. The aim of the study was to examine selected parameters of oxidative stress in patients with HCM compared to the control group. We enrolled 85 consecutive HCM patients and 97 controls without HCM. The groups were matched for sex, the body mass index, and age. Oxidative stress markers included superoxide dismutase (SOD), ceruloplasmin (CER), and lipofuscin (LPS). The median age of the HCM patients was 53 (40-63) years, and 41.2% of them were male. HCM patients, compared to the control ones, had significantly increased levels of CER and LPS. The areas under the receiver operating characteristics curves (AUC) indicated a good discriminatory power of CER (AUC 0.924, sensitivity 84%, and specificity 88%), an acceptable discriminatory power of LPS (AUC 0.740, sensitivity 66%, and specificity 72%), and poor discriminatory power of SOD (AUC 0.556, sensitivity 34%, and specificity 94%) for HCM detection. CER with good predictive strength, as well as LPS with acceptable predictive power, allows for HCM detection. The utility of SOD for HCM detection is limited.

Aberrant lipid accumulation and retinal pigment epithelium dysfunction in PRCD-deficient mice

Progressive Rod-Cone Degeneration (PRCD) is an integral membrane protein found in photoreceptor outer segment (OS) disc membranes and its function remains unknown. Mutations in Prcd are implicated in Retinitis pigmentosa (RP) in humans and multiple dog breeds. PRCD-deficient models exhibit decreased levels of cholesterol in the plasma. However, potential changes in the retinal cholesterol remain unexplored. In addition, impaired phagocytosis observed in these animal models points to potential deficits in the retinal pigment epithelium (RPE). Here, using a Prcd−/− murine model we investigated the alterations in the retinal cholesterol levels and impairments in the structural and functional integrity of the RPE. Lipidomic and immunohistochemical analyses show a 5-fold increase in the levels of cholesteryl esters (C.Es) and lipid deposits in the PRCD-deficient retina, respectively, indicating alterations in total retinal cholesterol. Furthermore, the RPE of Prcd−/− mice exhibit a 1.7-fold increase in the expression of lipid transporter gene ATP-binding cassette transporter A1 (Abca1). Longitudinal fundus and spectral domain optical coherence tomography (SD-OCT) examinations showed focal lesions and RPE hyperreflectivity. Strikingly, the RPE of Prcd−/− mice exhibited age-related pathological features such as lipofuscin accumulation, Bruch's membrane (BrM) deposits and drusenoid focal deposits, mirroring an Age-related Macular Degeneration (AMD)-like phenotype. We propose that the extensive lipofuscin accumulation likely impairs lysosomal function, leading to the defective phagocytosis observed in Prcd−/− mice. Our findings support the dysregulation of retinal cholesterol homeostasis in the absence of PRCD. Further, we demonstrate that progressive photoreceptor degeneration in Prcd−/− mice is accompanied by progressive structural and functional deficits in the RPE, which likely exacerbates vision loss over time.

Anoectochilus roxburghii Extract Extends the Lifespan of Caenorhabditis elegans through Activating the daf-16/FoxO Pathway.

As a significant global issue, aging is prompting people's interest in the potential anti-aging properties of Anoectochilus roxburghii (A. roxburghii), a plant traditionally utilized in various Asian countries for its purported benefits in treating diabetes and combating aging. However, the specific anti-aging components and mechanisms of A. roxburghii remain unclear. This study aims to investigate the anti-aging effects and mechanisms of A. roxburghii extract E (ARE). Caenorhabditis elegans (C. elegans) were exposed to media containing different concentrations of ARE whose superior in vitro radical scavenging capacity was thus identified. Lifespan assays, stress resistance tests, and RT-qPCR analyses were conducted to evaluate anti-aging efficacy, reactive oxygen species (ROS) levels, antioxidant enzyme activity, and daf-16, sod-3, and gst-4 levels. Additionally, transcriptomic and metabolomic analyses were performed to elucidate the potential anti-aging mechanisms of ARE. Fluorescence protein assays and gene knockout experiments were employed to validate the impacts of ARE on anti-aging mechanisms. Our results revealed that ARE not only prolonged the lifespan of C. elegans but also mitigated ROS and lipofuscin accumulation, and boosted resistance to UV and heat stress. Furthermore, ARE modulated the expression of pivotal anti-aging genes including daf-16, sod-3, and gst-4, facilitating the nuclear translocation of DAF-16. Significantly, ARE failed to extend the lifespan of daf-16-deficient C. elegans (CF1038), indicating its dependency on the daf-16/FoxO signaling pathway. These results underscored the effectiveness of ARE as a natural agent for enhancing longevity and stress resilience to C. elegans, potentially to human.

Autophagy in drusen biogenesis secondary to age-related macular degeneration.

Age-related macular degeneration (AMD) is an emerging cause of blindness in aged people worldwide. One of the key signs of AMD is the degeneration of the retinal pigment epithelium (RPE), which is indispensable for the maintenance of the adjacent photoreceptors. Because of impaired energy metabolism resulting from constant light exposure, hypoxia, and oxidative stress, accumulation of drusen in AMD-affected eyes is observed. Drusen contain damaged cellular proteins, lipoprotein particles, lipids and carbohydrates and they are related to impaired protein clearance, inflammation, and extracellular matrix modification. When autophagy, a major cellular proteostasis pathway, is impaired, the accumulations of intracellular lipofuscin and extracellular drusen are detected. As these aggregates grow over time, they finally cause the disorganisation and destruction of the RPE and photoreceptors leading to visual loss. In this review, the role of autophagy in drusen biogenesis is discussed since impairment in removing cellular waste in RPE cells plays a key role in AMD progression. In the future, means which improve intracellular clearance might be of use in AMD therapy to slow the progression of drusen formation.

Superoxide signal orchestrates tetrathiomolybdate-induced longevity via ARGK-1 in Caenorhabditis elegans

PurposeWhile reactive oxygen species (ROS) have been identified as key redox signaling agents contributing to aging process, which and how specific oxidants trigger healthy longevity remain unclear. This paper aimed to explore the precise role and signaling mechanism of superoxide (O2•−) in health and longevity. MethodsA tool for precise regulation of O2•− levels in vivo was developed based on the inhibition of superoxide dismutase 1 (SOD1) by tetrathiomolybdate (TM) in Caenorhabditis elegans (C. elegans). Then, we examined the effects of TM on lifespan, reproduction, lipofuscin accumulation, mobility, and stress resistance. Finally, the signaling mechanism for longevity induced by TM-O2•− was screened by transcriptome analysis and tested in sod-1 and argk-1 RNAi strains, sod-2, sod-3, and daf-16 mutants. ResultsTM promoted longevity in C. elegans with a concomitant extension of healthy lifespan as indicated by increasing fertility and mobility and reducing lipofuscin accumulation, as well as enhanced resistance to different abiotic stresses. Mechanically, TM could precisely regulate O2•− levels in nematodes via modulating SOD1 activity. An O2•− scavenger Mn(III)TBAP abolished TM-induced lifespan extension, while an O2•− generator paraquat at low concentration mimicked the life prolongation effects. The longevity in TM-treated worms was abolished by sod-1 RNAi but was not affected in sod-2 or sod-3 mutants. Further transcriptome analysis revealed arginine kinase ARGK-1 and its downstream insulin/insulin-like growth factor 1 signaling (IIS) as potential effectors for TM-O2•‾-induced longevity, and argk-1 RNAi or daf-16 mutant nullified the longevity. ConclusionsThese findings indicate that it is feasible to precisely control specific oxidant in vivo and O2•− orchestrates TM-induced health and longevity in C. elegans via ARGK-1-IIS axis.