Hallmark Of Aging Research Articles

Sustainable Skincare Innovation: Cork Powder Extracts as Active Ingredients for Skin Aging

Background: An emerging practice within the concept of circular beauty involves the upcycling of agro-industrial by-products. Cork processing, for instance, yields by-products like cork powder, which presents an opportunity to create value-added cosmetic ingredients. Building upon our previous research, demonstrating the antioxidant potential of hydroalcoholic extracts derived from two distinct cork powders (P0 and P1), in this work, aqueous extracts were prepared and analyzed. The safety and bioactivities of the newly obtained aqueous extracts, as well as the 30% ethanol extracts, previously reported to be the most promising for skin application, were also evaluated. Methods: Aqueous extracts were obtained from cork powders (P0 and P1) and the identification and quantification of some polyphenols was achieved by liquid chromatography (LC). Antioxidant potential was screened by DPPH method and the bioactivity and safety of extracts were further explored using cell-based assays. Results: All extracts exhibited a reduction in age-related markers, including senescence-associated beta-galactosidase (SA-β-gal) activity. Additionally, they demonstrated a pronounced anti-inflammatory effect by suppressing the production of several pro-inflammatory mediators in macrophages upon lipopolysaccharide stimulation. Moreover, the extracts upregulated genes and proteins associated with antioxidant activity, such as heme oxygenase 1. The aqueous extract from P1 powder was especially active in reducing pro-inflammatory mediators, namely the Nos2 gene, inducible nitric oxide protein levels, and nitric oxide production. Moreover, it did not induce skin irritation, as assessed by the EpiSkin test, in compliance with the OECD Test Guidelines. Conclusions: Overall, our findings underscore the potential of aqueous extracts derived from cork waste streams to mitigate various hallmarks of skin aging, including senescence and inflammaging, and their suitability for incorporation into cosmetics formulations. These results warrant further exploration for their application in the pharmaceutical and cosmetic industries and could foster a sustainable and circular bioeconomy.

Dasatinib and Quercetin Limit Gingival Senescence, Inflammation, and Bone Loss.

Cellular senescence has emerged as one of the central hallmarks of aging and drivers of chronic comorbidities, including periodontal diseases. Senescence can also occur in younger tissues and instigate metabolic alterations and dysfunction, culminating in accelerated aging and pathological consequences. Senotherapeutics, such as the combination of dasatinib and quercetin (DQ), are being increasingly used to improve the clinical outcomes of chronic disorders and promote a healthy life span through the reduction of senescent cell burden and senescence-associated secretory phenotype (SASP). Recent evidence suggests that senescent cells and SASP can contribute to the pathogenesis of periodontal diseases as well. In this study, we investigated the effect of DQ interventions on periodontal tissue health using preclinical models of aging. In vitro, DQ ameliorated biological signatures of senescence in human gingival keratinocytes upon persistent exposure to periodontal bacteria, Fusobacterium nucleatum, by modulating the levels of key senescence markers such as p16, SA-β-galactosidase, and lamin-B1 and inflammatory mediators associated with SASP including interleukin-8, matrix metalloproteinase (MMP)-1, and MMP-3. In vivo, the oral administration of DQ mitigated senescent cell burden and SASP in gingival tissues and reduced naturally progressing periodontal bone loss in aged mice. Collectively, our findings provide proof-of-concept evidence for translational studies and reveal that targeting gingival senescence and the senescence-associated secretome can be an effective strategy to improve periodontal health, particularly in vulnerable populations.

Exosomal miR-302b rejuvenates aging mice by reversing the proliferative arrest of senescent cells.

Cellular senescence, a hallmark of aging, involves a stable exit from the cell cycle. Senescent cells (SnCs) are closely associated with aging and aging-related disorders, making them potential targets for anti-aging interventions. In this study, we demonstrated that human embryonic stem cell-derived exosomes (hESC-Exos) reversed senescence by restoring the proliferative capacity of SnCs invitro. In aging mice, hESC-Exos treatment remodeled the proliferative landscape of SnCs, leading to rejuvenation, as evidenced by extended lifespan, improved physical performance, and reduced aging markers. Ago2 Clip-seq analysis identified miR-302b enriched in hESC-Exos that specifically targeted the cell cycle inhibitors Cdkn1a and Ccng2. Furthermore, miR-302b treatment reversed the proliferative arrest of SnCs invivo, resulting in rejuvenation without safety concerns over a 24-month observation period. These findings demonstrate that exosomal miR-302b has the potential to reverse cellular senescence, offering a promising approach to mitigate senescence-related pathologies and aging.

Knockdown of CNOT3, a subunit of the CCR4-NOT deadenylase complex, sensitizes A549 human non-small cell lung cancer cells to senescence-inducing stimuli.

Cellular senescence is an essentially irreversible cell cycle arrest associated with upregulated inflammatory responses that contribute to various pathological and physiological processes, including aging, cancer, and cancer prevention. However, the underlying mechanisms are not fully understood. Here, we show that the downregulation of CNOT3, a subunit of the CCR4-NOT complex that deadenylates mRNA poly(A) tails, promotes cellular senescence in subpopulation of A549 human non-small cell lung cancer cells. Previous work has shown that CNOT3 knockdown upregulates p21 (CDKN1A), a cyclin-dependent kinase inhibitor. Since p21 is one of the key regulators of cellular senescence, we hypothesized that CNOT3 downregulation might lead to cellular senescence. Indeed, CNOT3 knockdown upregulates several key cellular senescence hallmarks, including p53, senescence-associated β-galactosidase activity, and senescence-associated secretory phenotype in subpopulation of A549cell culture. The senescent cell hallmarks were more prominent in the culture after additional treatment with BI 2536, a polo-like kinase 1 inhibitor. These results suggest that CNOT3 downregulation followed by BI 2536 treatment upregulates the hallmarks of cellular senescence in A549cell culture.

Cellular senescence-associated genes in rheumatoid arthritis: Identification and functional analysis.

Rheumatoid arthritis (RA), a long-term autoinflammatory condition causing joint damage and deformities, involves a multifaceted pathogenesis with genetic, epigenetic, and immune factors, including early immune aging. However, its precise cause remains elusive. Cellular senescence, a hallmark of aging marked by a permanent halt in cell division due to damage and stress, is crucial in aging and related diseases. In our study, we analyzed RA microarray data from the Gene Expression Omnibus (GEO) and focused on cellular senescence genes from the CellAge database. We started by selecting five RA datasets from GEO. Next, we pinpointed 29 differentially expressed genes (DEGs) linked to cellular senescence in RA, aligning them with genes from CellAge. We explored the roles of these DEGs in cellular senescence through Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. We then pinpointed three key genes (DHX9, CYR61, and ITGB) using random forest and LASSO Cox regression machine learning techniques. An integrated diagnostic model was created using these genes. We also examined the variance in immune cell infiltration and immune checkpoint gene expression between RA and normal samples. Our methodology's predictive accuracy was confirmed in external validation cohorts. Subsequently, RA samples were classified into three distinct subgroups based on the cellular senescence-associated DEGs, and we compared their immune landscapes. Our findings reveal a significant impact of cellular senescence-related DEGs on immune cell infiltration in RA samples. Hence, a deeper understanding of cellular senescence in RA could offer new perspectives for diagnosis and treatment.

METFORMIN AS A POTENTIAL PHARMACOLOGIC INTERVENTION TO IMPROVE HEALTHSPAN

Abstract Metformin is the most widely used oral antidiabetic drug, generally recommended as first-line treatment for type 2 diabetes as well as for diabetes prevention. Metformin extends lifespan in preclinical models, and several observational studies in humans suggest that metformin reduces cancer, cardiovascular disease, dementia, frailty, and all-cause mortality. Therefore, given that it is well-tolerated, safe, and widely used, there is high interest in testing its role as a potential agent to reduce age-related diseases and geriatric syndromes. The exact mechanisms by which metformin exerts these benefits are still being elucidated, but in addition to activating AMPK emerging evidence demonstrates metformin modulates several hallmarks of aging, such as epigenetic modifications, mitochondrial function, cellular senescence and the gut microbiome. Thus, metformin has pleiotropic effects which may contribute, perhaps collectively, to its aging-modulating properties. To date there are few clinical trials of metformin to directly examine metformin’s effects on human healthspan. We are currently conducting a randomized placebo-controlled clinical trial of metformin to prevent frailty in older adults with glucose intolerance, which will also examine the effects of metformin on several hallmarks of aging. Metformin is also being examined in a separate ongoing randomized placebo-controlled trial as a potential therapy to prevent Alzheimer’s disease in older adults without diabetes (including those who have prediabetes). Given its tolerability and safety profile, metformin could be quickly translated to clinical use if ongoing and future clinical trials demonstrate its efficacy in promoting healthspan.

SKELETAL MUSCLE MITOCHONDRIAL FUNCTION AND LONGITUDINAL CHANGES IN BRAIN STRUCTURE

Abstract Mitochondrial dysfunction, a hallmark of aging, has been associated with future cognitive impairment or dementia, as well as PET and blood biomarkers of Alzheimer’s disease and neurodegeneration. Whether mitochondrial dysfunction is associated with accelerated loss in brain volumes and microstructural integrity is unknown. We tested the longitudinal association between in vivo muscle mitochondrial oxidative capacity assessed via MR spectroscopy (post-exercise recovery rate of phosphocreatine, kPCr) and changes in brain MRI volumes and DTI microstructure over up to 12 years of follow-up in the Baltimore Longitudinal Study of Aging (2008-2020). In linear mixed effects models, adjusted for demographics, PCr deletion, and physical activity, higher kPCr was associated with less ventricular enlargement, less worsening in MRI-derived brain aging and Alzheimer’s disease scores, and less regional atrophy, especially the primary sensorimotor cortex, temporal white and gray matter, thalamus, occipital areas, cingulate cortex, and cerebellum (n=649). Higher kPCr was also associated with less microstructural integrity loss in white matter tracts connecting identified gray matter areas (n=598). Specific white matter tracts, including splenium of the corpus callosum and superior longitudinal fasciculus showed consistent longitudinal associations in radial diffusivity, but not axial diffusivity, which may indicate demyelination. Higher in vivo mitochondrial function is associated with less worsening in MRI-derived brain aging and Alzheimer’s disease scores, less brain atrophy in specific gray matter regions and less microstructural integrity loss in connecting white matter tracts. Future studies are warranted to investigate the role of CNS mitochondrial function in brain aging and neurodegeneration.

INTERDISCIPLINARY PERSPECTIVES ON CURRICULUM CONTENT FOR TRANSLATIONAL GEROSCIENCE EDUCATION

Abstract Translational geroscience is a new field of study that aims to delay, prevent or alleviate several aging-related diseases simultaneously by targeting the so-called “biological hallmarks of aging,” a constellation of biological pathways at the root of natural aging and chronic conditions for which aging is the major risk factor (e.g., diabetes, cardiovascular disease, Alzheimer’s, cancer). Geroscience is a paradigm shift in healthcare because it aims to move away from single disease management to multi-disease prevention or alleviation and decrease the period of morbidity at the end of life. In order to train a workforce in conducting translational geroscience trials, the Geroscience Education and Training Network (NIH/NIA R25AG073119) is developing curricula towards a Certificate in Geroscience Research Program. This program is designed to train investigators in aspects specific to clinical trials of geroscience guided interventions (pharmaceutical or behavioral) in older adults. Evidence suggests that many factors often not considered in trial design play an important role in the outcomes of these trials; for example, social determinants of health contribute to accelerated aging and worse outcomes in minority populations, socially-disadvantaged persons, and other vulnerable populations, where chronic diseases arise at a much younger age. This symposium aims to begin a conversation between biological scientists, behavioral and social scientists and others to address the question “What knowledge from your specific field do translational geroscientists need to know to conduct meaningful and impactful geroscience clinical trials?” This insight is essential to help develop the curricula required to train a well-rounded workforce of translational geroscientists.

DNMT3a Deficiency Contributes to Anesthesia/Surgery-Induced Synaptic Dysfunction and Cognitive Impairment in Aged Mice.

Perioperative neurocognitive disorder (PND) is a severe postoperative complication in older patients. Epigenetic changes are hallmarks of senescence and are closely associated with cognitive impairment. However, the effects of anesthesia and surgery on the aging brain's epigenetic regulatory mechanisms and its impact on cognitive impairment remain unclear. Using a laparotomy PND model, we report significant reduction in DNA methyltransferase 3a (DNMT3a) in hippocampal neurons of aged mice, which causes global DNA methylation decrease. Knockdown of DNMT3a leads to synaptic disorder and memory impairment in aged mice. Mechanistically, bisulfite sequencing revealed that DNMT3a deficiency reduces methylation in the LRG1 promoter region and promotes its transcription. We also show that activation of TGF-β signaling by the increase in LRG1 level, ultimately impacts the synaptic function. In contrast, both overexpressing DNMT3a or knockdown LRG1 in hippocampus can attenuate the synaptic disorders and rescue postoperative cognitive deficits in aged mice. Our results reveal that DNMT3a is a previously undefined mediator in the pathogenesis of PND, which couples epigenetic regulations with anesthesia/surgery-induced synaptic dysfunction and represents a therapeutic target to tackle PND.

Nuclear respiratory factor‐1 (NRF1) induction as a powerful strategy to deter mitochondrial dysfunction and senescence in mesenchymal stem cells

AbstractMesenchymal stem cells (MSCs) are promising candidates for regenerative therapies due to their self‐renewal and differentiation capabilities. Pathological microenvironments expose MSCs to senescence‐inducing factors such as reactive oxygen species (ROS), resulting in MSC functional decline and loss of stemness. Oxidative stress leads to mitochondrial dysfunction, a hallmark of senescence, and is prevalent in aging tissues characterized by elevated ROS levels. We hypothesized that overexpression of nuclear respiratory factor‐1 (NRF1), a driver of mitochondrial biogenesis, could metabolically potentiate MSCs and prevent MSC senescence. Single‐cell RNA sequencing (scRNA‐Seq) revealed that MSCs transfected with NRF1 messenger RNA (mRNA) exhibited upregulated expression of genes associated with oxidative phosphorylation (OXPHOS), decreased glycolytic markers, and suppression of senescence‐related pathways. To test whether NRF1 induction could mitigate stress‐induced premature senescence, we exposed MSCs to hydrogen peroxide (H2O2) and validated our findings in a replicative senescence model. NRF1 mRNA transfection significantly increased mitochondrial mass and improved aberrant mitochondrial processes associated with senescence, including reduced mitochondrial and intracellular total ROS production. Mitochondrial health and dynamics were preserved, and respiratory function was restored, as evidenced by enhanced OXPHOS, reduced glycolysis, and increased ATP production. Notably, NRF1 overexpression led to decreased senescence‐associated β‐galactosidase (SA‐β‐gal) activity and reduced expression of senescence markers p53, p21, and p16. Our findings demonstrate that NRF1 induction attenuates MSC senescence by enhancing mitochondrial function, suggesting potential translational applications for MSC‐based therapies and senescence‐targeted interventions.

Cross comparison of imaging strategies of mitochondria in C. elegans during aging.

Mitochondria are double membrane-bound organelles with pleiotropic roles in the cell, including energy production through aerobic respiration, calcium signaling, metabolism, proliferation, immune signaling, and apoptosis. Dysfunction of mitochondria is associated with numerous physiological consequences and drives various diseases, and is one of twelve biological hallmarks of aging, linked to aging pathology. There are many distinct changes that occur to the mitochondria during aging including changes in mitochondrial morphology, which can be used as a robust and simple readout of mitochondrial quality and function. Although mitochondrial morphology alone cannot be used to conclude the quality of mitochondria, it is highly correlated with mitochondrial function whereby mitochondria exhibit increased fragmentation with age in multiple cell types of the nematode C. elegans. Thus, C. elegans serve as a robust model for rapidly measuring mitochondrial morphology changes during aging. To standardize imaging methods for mitochondrial morphology in C. elegans, we provide a detailed comparative characterization of several transgenic constructs, highlighting benefits and caveats for aging biology studies.

Time restricted feeding with or without ketosis influences metabolism-related gene expression in a tissue-specific manner in aged rats.

Many of the 'hallmarks of aging' involve alterations in cellular and organismal metabolism. One pathway with the potential to impact several traditional markers of impaired function with aging is the PI3K/AKT metabolic pathway. Regulation of this pathway includes many aspects of cellular function, including protein synthesis, proliferation and survival, as well as many downstream targets, including mTOR and FOXOs. Importantly, this pathway is pivotal to the function of every organ system in the human body. Thus, we investigated the expression of several genes along this pathway in multiple organs, including the brain, liver and skeletal muscle, in aged subjects that had been on different experimental diets to regulate metabolic function since mid-life. Specifically, rats were fed a control ad lib diet (AL), a time restricted feeding diet (cTRF), or a time restricted feeding diet with ketogenic macronutrients (kTRF) for the majority of their adult lives (from 8-25 months). We previously reported that regardless of macronutrient ratio, TRF-fed rats in both macronutrient groups required significantly less training to acquire a biconditional association task than their ad lib fed counterparts. The current experiments expand on this work by quantifying metabolism-related gene expression across tissues and interrogating for potential relationships with cognitive performance. AKT expression was significantly reduced in kTRF fed rats within liver and muscle tissue. However, AKT expression within the perirhinal cortex (PER) was higher in kTRF rats with the best cognitive performance. Within CA3, higher levels of FOXO1 gene expression correlated with poorer cognitive performance in ad libitum fed rats. Together, these data demonstrate diet- and tissue-specific alterations in metabolism-related gene expression and their correlation with cognitive status.

Impaired renal transporter gene expression and uremic toxin excretion as aging hallmarks in cats with naturally occurring chronic kidney disease.

Aging leads to nephron senescence and chronic kidney disease (CKD). In cats, indoxyl sulfate (IxS) has been previously quantified and associated with CKD, and little is known about tubular transporters. Two cohorts of cats aged 6 to 21 years were enrolled. Cohort 1 included 41 colony cats with 28 control and 13 CKD cats. Cohort 2 had 30 privately-owned cats with 10 control and 20 CKD cats. In cohort 1, serum concentrations of IxS, trimethylamine N-oxide (TMAO), p-cresol sulfate (PCS), and phenyl sulfate were higher in CKD vs. control cats (all P<0.05). This observation was independently validated in cohort 2. Renal cortical and medullar tissues were collected from a third cohort of cats euthanized for humane reasons unrelated to the study. We provided the evidence that renal tubular transporter genes, OAT1, OAT4, OATP4C1, and ABCC2, but not OAT3, were expressed in the kidneys of cats, and their expressions were downregulated in CKD (all FDR<0.1). Cats and humans share 90.9%, 77.8%, and 82.5% identities in OAT1, OATP4C1, and ABCC2 proteins, respectively. In healthy cats, circulating TMAO and IxS are significantly correlated with age. Our study reveals impaired uremic toxin secretion and tubular transporter expression in cats with CKD.

How do proteins shape our lifespan? Exploring aging at the molecular level

Aging is a major risk factor for many diseases, including neurodegenerative, diabetes, cancer and cardiovascular diseases. Protein misfolding and consequent aggregation are key pathogenic features of number of age-related disorders. Therefore, correct protein folding and its maintenance are necessary for all cellular health. Proper functional balance of the cellular proteins referred as protein homeostasis (or proteostasis) is vital for all living cells. Thus, cells maintain protein quality control systems or proteostasis network (PN), which coordinates protein synthesis, folding, and degradation to protect the proteins. However, PN function declines with age, and loss of proteostasis is considered as one of the primary hallmarks of aging. It is not clear whether aging is a cause or consequence of proteostasis decline. Intriguingly, signaling pathways that regulate longevity are also found to modulate the PN. This raises a question whether aging pathways can be targeted to boost proteostasis and extend healthy lifespan. This essay explores the relationship between proteins, aging, and strategies to improve both lifespan and health span.

Dog Aging: A Comprehensive Review of Molecular, Cellular, and Physiological Processes.

The aging process is a multifactorial biological phenomenon starting at birth and persisting throughout life, characterized by a decline in physiological functions and adaptability. This decline results in the diminished capacity of aging organisms to respond to environmental changes and stressors, leading to reduced efficiency in metabolic, immune, and hormonal functions. As behavioral flexibility wanes, older individuals face longer recovery times and increased vulnerability to diseases. While early research proposed nine core hallmarks of mammalian aging, recent studies have expanded this framework to twelve key characteristics: epigenetic changes, genomic instability, telomere shortening, loss of proteostasis, altered metabolism, mitochondrial dysfunction, cellular senescence, disrupted intercellular communication, stem cell depletion, immune system dysfunction, accumulation of toxic metabolites, and dysbiosis. Given the growing interest in the aging area, we propose to add a new hallmark: impaired water homeostasis. This potential hallmark could play a critical role in aging processes and might open new directions for future research in the field. This review enhances our understanding of the physiological aspects of aging in dogs, suggesting new clinical intervention strategies to prevent and control issues that may arise from the pathological degeneration of these hallmarks.

Canagliflozin treatment prevents follicular exhaustion and attenuates hallmarks of ovarian aging in genetically heterogenous mice.

Ovarian aging is characterized by declines in follicular reserve and the emergence of mitochondrial dysfunction, reactive oxygen species production, inflammation, and fibrosis, which eventually results in menopause. Menopause is associated with increased systemic aging and the development of numerous comorbidities; therefore, the attenuation of ovarian aging could also delay systemic aging processes in women. Recent work has established that the anti-diabetic drug Canagliflozin (Cana), a sodium-glucose transporter 2 inhibitor, elicits benefits on aging-related outcomes, likely through the modulation of nutrient-sensing pathways and metabolic homeostasis. Given that nutrient-sensing pathways play a critical role in controlling primordial follicle activation, we sought to determine if chronic Cana administration would delay ovarian aging and curtail the emergence of pathological hallmarks associated with reproductive senescence. We found that mice receiving Cana maintained their ovarian reserve through 12months of age, which was associated with declines in primordial follicles FoxO3a phosphorylation, a marker of activation, when compared to the age-matched controls. Furthermore, Cana treatment led to decreased collagen, lipofuscin, and T cell accumulation at 12months of age. Whole ovary transcriptomic and proteomic analyses revealed subtle improvements, predominantly in mitochondrial function and the regulation of cellular proliferation. Pathway analyses of the transcriptomic data revealed a downregulation in cell proliferation and mitochondrial dysfunction signatures, with an upregulation of oxidative phosphorylation. Pathway analyses of the proteomic data revealed declines in signatures associated with PI3K/AKT activity and lymphocyte accumulation. Collectively, we demonstrate that Cana treatment can delay ovarian aging in mice and could potentially have efficacy for delaying ovarian aging in women.

Human Liver MSCs Retain Their Basic Cellular Properties in Chronically Inflamed Liver Tissue.

Every 25th death worldwide is associated with liver pathology. The development of novel approaches to liver diseases therapy and protocols for maintaining the vital functions of patients on the liver transplant waiting list are urgently needed. Resident mesenchymal stem cells (MSCs) play a significant role in supporting liver tissue integrity and improve the liver condition after infusion. However, it remains unclear whether MSCs isolated from chronically inflamed livers are similar in their basic cellular properties to MSCs obtained from healthy livers. We applied a large array of tests to compare resident MSCs isolated from apparently normal liver tissue and from chronically inflamed livers of patients with fibrosis, cirrhosis, and viral hepatitis. Chronic inflammatory environment did not alter the major cellular characteristics of MSCs, including the expression of MSC markers, stem cell markers, adhesion molecules, and the hallmarks of senescence, as well as cell proliferation, migration, and secretome. Only the expression of some immune checkpoints and toll-like receptors was different. Evidently, MSCs with unchanged cellular properties are present in human liver even at late stages of inflammatory diseases. These cells can be isolated and used as starting material in the development of cell therapies of liver diseases.

Nuclear lipid droplets: a novel regulator of nuclear homeostasis and ageing.

Aging is a fundamental driver of numerous life-threatening diseases, significantly compromising cellular structures and functions, including the integrity of the nucleus. A consistent feature of aging across diverse species is the progressive accumulation of lipid droplets (nLDs) within the nuclear compartment, which disrupts nuclear architecture and functionality. Notably, aging is accompanied by a marked increase in nLD accumulation at the nuclear envelope. Interventions known to extend lifespan, such as caloric restriction and reduced insulin signaling, significantly reduce both the rate of accumulation and the size of nLDs. The triglyceride lipase ATGL-1, which localizes to the nuclear envelope, plays a critical role in limiting nLD buildup and maintaining nuclear lipid balance, especially in long-lived mutant worms. These findings establish excessive nuclear lipid deposition as a key hallmark of aging, with profound implications for nuclear processes such as chromatin organization, DNA repair, and gene regulation. In addition, ATGL-1 emerges as a promising therapeutic target for preserving nuclear health, extending organismal healthspan, and combating age-related disorders driven by lipid dysregulation.

1,2-Dihydroxy-9H-Xanthen-9-One, a Multifunctional Nature-Inspired Active Ingredient

Incorporating antioxidants into cosmetics is the mainstay for developing new products to mitigate skin aging. However, identifying novel multifunctional antioxidant ingredients with additional relevant properties that block the skin hallmarks of aging is a very striking strategy. Many natural compounds, including xanthones, have demonstrated biologically notable properties. In particular, 1,2-dihydroxy-9H-xanthen-9-one (1,2-DHX) has inhibitory activity against skin enzymes, and metal-chelating and radical-scavenging activities. Therefore, 1,2-DHX is an attractive molecule for cosmetic purposes. With this goal in mind, the anti-inflammatory, antioxidant, and anti-allergic potentials of 1,2-DHX were investigated. 1,2-DHX demonstrated anti-inflammatory properties by inhibiting the synthesis of specific pro-inflammatory mediators, including interleukin-6 (IL-6) and prostaglandin E2 (PGE2), in human macrophages. This xanthone did not elicit sensitization reactions and did inhibit allergic reactions triggered by a strong skin allergen, suggesting its potential as an anti-allergic compound. 1,2-DHX also revealed mitochondrial antioxidant activity by mitigating rotenone-induced oxidative stress in macrophages by up to 40%. Overall, 1,2-DHX displayed a safety profile and noteworthy biological activities, highlighting its multifunctional profile as an active cosmetic ingredient with anti-inflammatory, antioxidant, and anti-allergic properties.

Multinucleated giant cells are hallmarks of ovarian aging with unique immune and degradation-associated molecular signatures.

The ovary is one of the first organs to exhibit signs of aging, characterized by reduced tissue function, chronic inflammation, and fibrosis. Multinucleated giant cells (MNGCs), formed by macrophage fusion, typically occur in chronic immune pathologies, including infectious and non-infectious granulomas and the foreign body response 1 , but are also observed in the aging ovary 2-4 . The function and consequence of ovarian MNGCs remain unknown as their biological activity is highly context-dependent, and their large size has limited their isolation and analysis through technologies such as single-cell RNA sequencing. In this study, we define ovarian MNGCs through a deep analysis of their presence across age and species using advanced imaging technologies as well as their unique transcriptome using laser capture microdissection. MNGCs form complex interconnected networks that increase with age in both mouse and nonhuman primate ovaries. MNGCs are characterized by high Gpnmb expression, a putative marker of ovarian and non-ovarian MNGCs 5,6 . Pathway analysis highlighted functions in apoptotic cell clearance, lipid metabolism, proteolysis, immune processes, and increased oxidative phosphorylation and antioxidant activity. Thus, MNGCs have signatures related to degradative processes, immune function, and high metabolic activity. These processes were enriched in MNGCs compared to primary ovarian macrophages, suggesting discrete functionality. MNGCs express CD4 and colocalize with T-cells, which were enriched in regions of MNGCs, indicative of a close interaction between these immune cell types. These findings implicate MNGCs in modulation of the ovarian immune landscape during aging given their high penetrance and unique molecular signature that supports degradative and immune functions.