Age-related Pathologies Research Articles

GLP1 Receptor Agonists-Effects beyond Obesity and Diabetes.

Glucagon-like peptide-1 receptor agonists (GLP1RA) have been transformative for patients and clinicians in treating type-2 diabetes and obesity. Drugs of this class, the bioavailability of which is continuously improving, enable weight loss and control blood glucose with minimal unwanted side effects. Since adopting GLP1RA for treating metabolic diseases, animal and clinical studies have revealed their beneficial effects on several other pathologies, including cardiovascular diseases, neurodegeneration, kidney disease, and cancer. A notable commonality between these diseases is their association with older age. Clinical trials and preclinical data suggest that GLP1RA may improve outcomes in these aging-related diseases. Some of the benefits of GLP1RA may be indirect due to their effects on obesity and glucose metabolism. However, there is building evidence that GLP1RA may also act directly on multiple organs implicated in aging-related pathology. This review aims to compile the studies reporting the effects of GLP1RA on aging-related diseases and discuss potential underlying mechanisms.

Cellular Reprogramming, Transdifferentiation and Alleviation of the Aging Pathology

Cellular reprogramming and transdifferentiation have emerged as transformative technologies in regenerative medicine, holding significant promise for addressing age-related pathologies and rare genetic disorders. Dr. Shinya Yamanaka's pioneering work in cellular reprogramming paved the way for the restoration of pluripotency in terminally differentiated cells. The understanding that exogenous introduction of the key transcription factors (Oct4, Sox2, KLF4 and c-Myc) enables cells for reprogramming, regaining pluripotency has provided tremendous opportunities and better platforms for therapeutic implications. Transdifferentiation, the conversion of one differentiated cell type to another, offers a complementary approach to cellular reprogramming and can be procured by modulating the expression of specific transcription factors, miRNAs, or other small molecules. Therapeutic approaches that utilize transdifferentiated cells are promising in addressing the age-related pathologies of vital organs such as the pancreas, liver, cardiovascular system as well as neurological disorders. Additionally, the emerging field of epigenetic rejuvenation offers extended possibilities for targeted interventions as it focuses on targeting age-associated CpG signatures of the epigenome. Induced pluripotent stem cells (iPSCs) obtained by cellular reprogramming have become invaluable tools for studying rare monogenic syndromes and premature aging diseases that include Hutchinson-Gilford Progeria Syndrome (HGPS) and Werner syndrome. iPSCs enable researchers to model diseases and gain insights into their underlying mechanisms. Translation of these technologies into clinical practice just needs bypassing hurdles related to safe, efficient, specific therapeutic outcomes. Thus, recent advancements in stem cell technologies highlight that cellular reprogramming and transdifferentiation are poised to revolutionize healthcare, providing novel approaches to address age-related pathologies and other genetic disorders.

Mitophagy Decreases in the Peripheral Vestibular System of Aged C57BL/6J Mice.

Mitophagy is a cardinal process for maintaining healthy and functional mitochondria. A decline in mitophagy has been associated with age-related pathologies. We aimed to investigate mitophagy changes in age-related balance problems using an animal model. C57BL/6J mice were divided into young (1 month old) and aged (12 months old) groups. Balance performance, mitochondrial DNA integrity, ATP content, mitophagic process, and mitophagy-related genes and proteins were investigated in both groups. Balance and motor performance were reduced in the aged group. Mitochondrial DNA integrity and ATP content, and mRNA levels of PINK1, Parkin, BNIP3, AMBRA1, MUL1, NIX, Bcl2-L-13, Atg3, Atg5, Atg12, and Atg13 in the vestibule were significantly lower in aged mice compared with those in young mice. The protein levels of PINK1, Parkin, BNIP3, LC3B, and OXPHOS subunits were significantly decreased in the aged vestibule. Mitophagosome and mitophagolysosome counts and the immunohistochemical expression of Parkin and BNIP3 were also decreased in the saccule, utricle, and crista ampullaris in the aged group. A general decrease in mitophagy with aging might be attributed to a decrease in cellular function in the aged vestibule during the development of age-related balance problems.

IDENTIFYING SENOLYTIC TARGETS OF DIETARY FLAVONOIDS IN RENAL CELLS BY THERMAL PROTEOME PROFILING

Abstract Senescent cell accumulation is a known driver of aging and age-related pathologies. Clearance of senescent cells is a promising approach to increase longevity and reduce multiple age-related diseases in humans. Flavonoid compounds are present in fruits and vegetables, of which certain flavonoids (e.g., quercetin and fisetin) have demonstrated senolytic, or ‘senescent-cell-killing’, activity in culture and in mice. However, the cellular mechanism of senolysis and the efficacy of these compounds are not known in renal epithelial cells. Here, we combine flavonoid drug screening, targeted metabolomics, and thermal proteome profiling (TPP) with analysis by mass spectrometry (MS) to explore protein targets of senolytic drugs in senescent human renal cortical epithelial cells and human renal proximal tubular epithelial cells. Senescence was induced by exposure to ionizing radiation and the senescence phenotype was validated through a rigorous panel of senescence and viability markers. Proliferating and senescent renal epithelial cells were screened with a panel of 8 flavonoids to identify senolytic drugs and their concentrations for selectively killing senescent cells. Targeted MS assays were developed to assess intracellular drug uptake, a potential mechanism of senescent-specific killing. To identify protein targets of the senolytic flavonoids in senescent cells, we performed a variation of TPP in combination with liquid chromatography (LC)-MS/MS proteomics analysis, carefully controlling for non-senolytic interactions by excluding proteins bound by a non-senolytic flavonoid. The results of this study pave the way for the development of a more specific generation of senolytic compounds and identify novel candidate senolytic pathways engaged by dietary flavonoids.

INTER-ORGANELLE CROSSTALK IN THE REGULATION OF AGING AND LONGEVITY

Abstract In eukaryotic cells, specific functions are compartmentalized into various organelles that are evolutionarily conserved across species. Many of these organelles play crucial roles in regulating cellular homeostasis and organismal health. Lysosomes, mitochondria, lipid droplets, and endoplasmic reticulum (ER) are highly metabolic active and support the metabolic balance of lipids, amino acids, carbohydrates, and nucleotides. These organelles also regulate signal transduction, transcriptional responses, and epigenetic dynamics, and contribute to the control of lifespan and healthspan in a variety of organisms. Importantly, these organelles do not act in isolation, instead exhibit complex intercommunication at structural, metabolic and signaling levels. The dysfunction of these organelles and their intercommunications have been associated with aging and age-related pathologies. This symposium aims to encourage innovative studies on the role of organelle interactions and communications in regulating aging and longevity. Speakers have been invited to share their new findings in this research topic. We will discuss how lysosomal metabolism couples with lysosomal signaling to regulate organelle crosstalk, tissue communication, and organism lifespan; how ER and mitochondria communicate through calcium signaling and promote longevity; how lipid droplets play a novel role in remodeling carbohydrate metabolism and define the metabolic balance in supporting organism health; and how lysosomal activity, mitochondrial function and cytosolic proteostasis orchestrate to support cellular homeostasis.

Rejuvenation of cerebromicrovascular function in aged mice through heterochronic parabiosis: insights into neurovascular coupling and the impact of young blood factors.

Age-related impairment of neurovascular coupling (NVC; "functional hyperemia") is a critical factor in the development of vascular cognitive impairment (VCI). Recent geroscience research indicates that cell-autonomous mechanisms alone cannot explain all aspects of neurovascular aging. Circulating factors derived from other organs, including pro-geronic factors (increased with age and detrimental to vascular homeostasis) and anti-geronic factors (preventing cellular aging phenotypes and declining with age), are thought to orchestrate cellular aging processes. This study aimed to investigate the influence of age-related changes in circulating factors on neurovascular aging. Heterochronic parabiosis was utilized to assess how exposure to young or old systemic environments could modulate neurovascular aging. Results demonstrated a significant decline in NVC responses in aged mice subjected to isochronic parabiosis (20-month-old C57BL/6 mice [A-(A)]; 6weeks of parabiosis) when compared to young isochronic parabionts (6-month-old, [Y-(Y)]). However, exposure to young blood from parabionts significantly improved NVC in aged heterochronic parabionts [A-(Y)]. Conversely, young mice exposed to old blood from aged parabionts exhibited impaired NVC responses [Y-(A)]. In conclusion, even a brief exposure to a youthful humoral environment can mitigate neurovascular aging phenotypes, rejuvenating NVC responses. Conversely, short-term exposure to an aged humoral milieu in young mice accelerates the acquisition of neurovascular aging traits. These findings highlight the plasticity of neurovascular aging and suggest the presence of circulating anti-geronic factors capable of rejuvenating the aging cerebral microcirculation. Further research is needed to explore whether young blood factors can extend their rejuvenating effects to address other age-related cerebromicrovascular pathologies, such as blood-brain barrier integrity.

AGE-RELATED KYNURENINE PATHWAY METABOLITES DRIVE SENESCENT-LIKE CHANGES IN NEURONS: POTENTIAL NOVEL AD MECHANISM

Abstract Kynurenine pathway (KP) metabolites are emerging as important factors of aging-related pathologies. Kynurenine (KYN) and its metabolites increase with age and are known to affect multiple organ systems including CNS, musculoskeletal, and vascular systems. Our group has previously shown that KYN and sub-KYN metabolites below the enzyme Kynurenine monooxygenase (KMO) can act to inhibit osteogenesis of bone marrow MSCs via senescence induction. However, inhibition of KMO, blocks KYN induced senescence and restores osteogenic potentials of MSCs. We are now expanding this work to see if KYN metabolites act on cells of the aging CNS in a similar fashion potentially helping to drive cognitive decline and Alzheimer’s disease (AD) progression. We report for the first time that treatment of neuroblastoma-like SH-SY5Y cells with KYN, and sub-KMO metabolites 3-hydroxykynurenine (3HK), or quinolinic acid (QA) significantly increased senescence-associate beta-galactosidase activity, and expression of senescence associated secretory phenotype (SASP) markers, p21, PAI-1, TIMP2 as well as Histone 3 K9methylation. Treatment of SH-SY5Y cells with KMO inhibitors prevented elevated expression of SASP proteins and histone methylation. This makes KMO an attractive target to inhibit kynurenine pathway effects. Taken together, these data suggest that KYN and its metabolites may contribute to pathogenesis of AD via inducing senescence-like changes and SASP-mediated neuroinflammation in neuronal cells. Inhibition of KMO may allow rescue of brain microenvironment, limit cognitive decline and AD progression in older persons. Blocking KYN downstream metabolite formation, by inhibiting KMO, presents a novel therapeutic target for a potential novel AD mechanism.

A dicer-related helicase opposes the age-related pathology from SKN-1 activation in ASI neurons.

Coordination of cellular responses to stress is essential for health across the lifespan. The transcription factor SKN-1 is an essential homeostat that mediates survival in stress-inducing environments and cellular dysfunction, but constitutive activation of SKN-1 drives premature aging thus revealing the importance of turning off cytoprotective pathways. Here, we identify how SKN-1 activation in two ciliated ASI neurons in Caenorhabditis elegans results in an increase in organismal transcriptional capacity that drives pleiotropic outcomes in peripheral tissues. An increase in the expression of established SKN-1 stress response and lipid metabolism gene classes of RNA in the ASI neurons, in addition to the increased expression of several classes of noncoding RNA, define a molecular signature of animals with constitutive SKN-1 activation and diminished healthspan. We reveal neddylation as a unique regulator of the SKN-1 homeostat that mediates SKN-1 abundance within intestinal cells. Moreover, RNAi-independent activity of the dicer-related DExD/H-box helicase, drh-1, in the intestine, can oppose the effects of aberrant SKN-1 transcriptional activation and delays age-dependent decline in health. Taken together, our results uncover a cell nonautonomous circuit to maintain organism-level homeostasis in response to excessive SKN-1 transcriptional activity in the sensory nervous system.

Mitochondrial DNA copy number variation across three generations: a possible biomarker for assessing perinatal outcomes

BackgroundMitochondria have their own circular multi-copy genome (mtDNA), and abnormalities in the copy number are implicated in mitochondrial dysfunction, which contributes to a variety of aging-related pathologies. However, not much is known about the genetic correlation of mtDNA copy number across multiple generations and its physiological significance.MethodsWe measured the mtDNA copy number in cord blood or peripheral blood from 149 three-generation families, specifically the newborns, parents, and grandparents, of 149 families, totaling 1041 individuals. All of the biological specimens and information were provided by the Tohoku Medical Megabank Project in Japan. We also analyzed their maternal factors during pregnancy and neonatal outcomes.ResultsWhile the maternal peripheral blood mtDNA copy number was lower than that of other adult family members, it was negatively correlated with cord blood mtDNA copy number in male infants. Also, cord blood mtDNA copy numbers were negatively correlated with perinatal outcomes, such as gestation age, birth weight, and umbilical cord length, for both male and female neonates. Furthermore, the mtDNA copy number in the infants born to mothers who took folic acid supplements during pregnancy would be lower than in the infants born to mothers who did not take them.ConclusionsThis data-driven study offers the most comprehensive view to date on the genetic and physiological significance of mtDNA copy number in cord blood or peripheral blood taken from three generations, totaling more than 1000 individuals. Our findings indicate that mtDNA copy number would be one of the transgenerational biomarkers for assessing perinatal outcomes, as well as that appropriate medical interventions could improve the outcomes via quantitative changes in mtDNA.

Clinicopathologic features of a novel star-shaped transactive response DNA-binding protein 43 (TDP-43) pathology in the oldest old.

Transactive response DNA-binding protein 43 (TDP-43) pathology is categorized as type A-E in frontotemporal lobar degeneration and as type α-β in Alzheimer disease (AD) based on inclusion type. We screened amygdala slides of 131 cases with varying ages at death, clinical/neuroimaging findings, and AD neuropathologic changes for TDP-43 pathology using anti-phospho-TDP-43 antibodies. Seven cases (5%) only showed atypical TDP-43 inclusions that could not be typed. Immunohistochemistry and immunofluorescence assessed the atypical star-shaped TDP-43 pathology including its distribution, species, cellular localization, and colocalization with tau. All 7 had died at an extremely old age (median: 100 years [IQR: 94-101]) from nonneurological causes and none had dementia (4 cognitively unimpaired, 3 with amnestic mild cognitive impairment). Neuroimaging showed mild medial temporal involvement. Pathologically, the star-shaped TDP-43-positive inclusions were found in medial (subpial) amygdala and, occasionally, in basolateral regions. Hippocampus only showed TDP-43-positive neurites in the fimbria and subiculum while the frontal lobe was free of TDP-43 inclusions. The star-shaped inclusions were better detected with antibodies against N-terminal than C-terminal TDP-43. Double-labeling studies confirmed deposition of TDP-43 within astrocytes and colocalization with tau. We have identified a novel TDP-43 pathology with star-shaped morphology associated with superaging, with a homogeneous clinicopathologic picture, possibly representing a novel, true aging-related TDP-43 pathology.

Aging and Inflammation.

Aging can be conceptualized as the progressive disequilibrium between stochastic damage accumulation and resilience mechanisms that continuously repair that damage, which eventually cause the development of chronic disease, frailty, and death. The immune system is at the forefront of these resilience mechanisms. Indeed, aging is associated with persistent activation of the immune system, witnessed by a high circulating level of inflammatory markers and activation of immune cells in the circulation and in tissue, a condition called "inflammaging." Like aging, inflammaging is associated with increased risk of many age-related pathologies and disabilities, as well as frailty and death. Herein we discuss recent advances in the understanding of the mechanisms leading to inflammaging and the intrinsic dysregulation of the immune function that occurs with aging. We focus on the underlying mechanisms of chronic inflammation, in particular the role of NF-κB and recent studies targeting proinflammatory mediators. We further explore the dysregulation of the immune response with age and immunosenescence as an important mechanistic immune response to acute stressors. We examine the role of the gastrointestinal microbiome, age-related dysbiosis, and the integrated stress response in modulating the inflammatory "response" to damage accumulation and stress. We conclude by focusing on the seminal question of whether reducing inflammation is useful and the results of related clinical trials. In summary, we propose that inflammation may be viewed both as a clinical biomarker of the failure of resilience mechanisms and as a causal factor in the rising burden of disease and disabilities with aging. The fact that inflammation can be reduced through nonpharmacological interventions such as diet and exercise suggests that a life course approach based on education may be a successful strategy to increase the health span with few adverse consequences.

Age-Associated Changes of Sirtuin 2 Expression in CNS and the Periphery.

Sirtuin 2 (SIRT2), one of the seven members of the sirtuin family, has emerged as a potential regulator of aging and age-related pathologies since several studies have demonstrated that it shows age-related changes in humans and different animal models. A detailed analysis of the relevant works published to date addressing this topic shows that the changes that occur in SIRT2 with aging seem to be opposite in the brain and in the periphery. On the one hand, aging induces an increase in SIRT2 levels in the brain, which supports the notion that its pharmacological inhibition is beneficial in different neurodegenerative diseases. However, on the other hand, in the periphery, SIRT2 levels are reduced with aging while keeping its expression is protective against age-related peripheral inflammation, insulin resistance, and cardiovascular diseases. Thus, systemic administration of any known modulator of this enzyme would have conflicting outcomes. This review summarizes the currently available information on changes in SIRT2 expression in aging and the underlying mechanisms affected, with the aim of providing evidence to determine whether its pharmacological modulation could be an effective and safe pharmacological strategy for the treatment of age-related diseases.

MiR-217 Regulates SIRT1 Expression and Promotes Inflammatory and Apoptotic Responses in Osteoarthritis.

Previous studies have reported miR-217 uregulation in age-related pathologies. We investigated the impact of miR-217-5p on sirtuin 1 (SIRT1) regulation in human osteoarthritic (OA) chondrocytes. MiR-217 target enrichment analyses were performed using three public databases, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. MiR-217-5p expression levels were quantified in normal and OA chondrocytes. SIRT1 expression levels, nuclear factor kappa-B p65 subunit (NF-κBp65) and p53 acetylation levels, and expression levels of OA-related pro-inflammatory markers [tumor necrosis factor α (TNFα), interleukin 1β (IL-1β), IL-6], pro-apoptotic markers [Bax, pro-caspase 3, cleaved caspase 3] and matrix regulators [matrix metalloproteinase (MMP)-1, MMP-13, MMP-9, Collagen 2 (COL2A1), Aggrecan (ACAN)] were evaluated in miR-217 mimic-treated and/or miR-217 inhibitor-treated OA chondrocytes, with/without subsequent treatment with siRNA against SIRT1 (siSIRT1). MiR-217-5p was upregulated in OA chondrocytes, while target prediction/enrichment analyses revealed SIRT1 as miR-217 target-gene. Deacetylation of NF-κBp65 and p53 in miR-217 inhibitor-treated OA chondrocytes was reversed by siSIRT1 treatment. MiR-217 inhibitor-treated OA chondrocytes showed increased COL2A1, ACAN and decreased IL-1β, IL-6, TNFα, Bax, cleaved caspase 3 and MMPs expression levels, which were reversed following miR-217 inhibitor/siSIRT1 treatment. Our findings highlight the impact of miR-217-5p on SIRT1 downregulation contributing to OA pathogenesis.

The role of cellular senescence in skin aging and age-related skin pathologies

Aging is the result of a gradual functional decline at the cellular, and ultimately, organismal level, resulting in an increased risk of developing a variety of chronic illnesses, such as cardiovascular disease, stroke, cancer and diabetes. The skin is the largest organ of the human body, and the site where signs of aging are most visible. These signs include thin and dry skin, sagging, loss of elasticity, wrinkles, as well as aberrant pigmentation. The appearance of these features is accelerated by exposure to extrinsic factors such as ultraviolet (UV) radiation or pollution, as well as intrinsic factors including time, genetics, and hormonal changes. At the cellular level, aging is associated with impaired proteostasis and an accumulation of macromolecular damage, genomic instability, chromatin reorganization, telomere shortening, remodelling of the nuclear lamina, proliferation defects and premature senescence. Cellular senescence is a state of permanent growth arrest and a key hallmark of aging in many tissues. Due to their inability to proliferate, senescent cells no longer contribute to tissue repair or regeneration. Moreover, senescent cells impair tissue homeostasis, promote inflammation and extracellular matrix (ECM) degradation by secreting molecules collectively known as the “senescence-associated secretory phenotype” (SASP). Senescence can be triggered by a number of different stimuli such as telomere shortening, oncogene expression, or persistent activation of DNA damage checkpoints. As a result, these cells accumulate in aging tissues, including human skin. In this review, we focus on the role of cellular senescence during skin aging and the development of age-related skin pathologies, and discuss potential strategies to rejuvenate aged skin.

Role of the kisspeptin-KISS1R axis in the pathogenesis of chronic kidney disease and uremic cardiomyopathy

The prevalence of chronic kidney disease (CKD) is increasing globally, especially in elderly patients. Uremic cardiomyopathy is a common cardiovascular complication of CKD, characterized by left ventricular hypertrophy (LVH), diastolic dysfunction, and fibrosis. Kisspeptins and their receptor, KISS1R, exert a pivotal influence on kidney pathophysiology and modulate age-related pathologies across various organ systems. KISS1R agonists, including kisspeptin-13 (KP-13), hold promise as novel therapeutic agents within age-related biological processes and kidney-related disorders. Our investigation aimed to elucidate the impact of KP-13 on the trajectory of CKD and uremic cardiomyopathy. Male Wistar rats (300–350 g) were randomized into four groups: (I) sham-operated, (II) 5/6 nephrectomy-induced CKD, (III) CKD subjected to a low dose of KP-13 (intraperitoneal 13 µg/day), and (IV) CKD treated with a higher KP-13 dose (intraperitoneal 26 µg/day). Treatments were administered daily from week 3 for 10 days. After 13 weeks, KP-13 increased systemic blood pressure, accentuating diastolic dysfunction’s echocardiographic indicators and intensifying CKD-associated markers such as serum urea levels, glomerular hypertrophy, and tubular dilation. Notably, KP-13 did not exacerbate circulatory uremic toxin levels, renal inflammation, or fibrosis markers. In contrast, the higher KP-13 dose correlated with reduced posterior and anterior wall thickness, coupled with diminished cardiomyocyte cross-sectional areas and concurrent elevation of inflammatory (Il6, Tnf), fibrosis (Col1), and apoptosis markers (Bax/Bcl2) relative to the CKD group. In summary, KP-13’s influence on CKD and uremic cardiomyopathy encompassed heightened blood pressure and potentially activated inflammatory and apoptotic pathways in the left ventricle.

Incremental residual polarization caused by aging in human skin.

The study of the effect of aging on the optical properties of biological tissues, in particular polarization, is important in the development of new diagnostic approaches. This work aims to provide a comprehensive analysis of the factors and mechanisms that contribute to the alteration of skin polarization properties caused by aging, using polarization-sensitive hyperspectral imaging measurements and Monte Carlo simulation. Our investigation involved both experimental studies of in vivo human skin of volunteers of different ages and computational modeling that accounted for changes in the absorption and scattering properties of the skin model. Specifically, we analyzed alterations in the degree of linear polarization (DOLP) to better understand the impact of aging on skin polarization properties. A statistically significant increase in the DOLP was found for the elderly group. At the same time, there was no correlation between changes in polarization and the calculated blood volume fraction parameter for different ages. According to the simulation results, it was also found that a change in the scattering properties of biological tissues has a more significant effect on the change in polarizing light compared to the change in absorption. The results of the work prove that the sensitivity of polarization imaging to age- or pathological-related skin changes may be primarily due to changes in scattering, which in turn is associated with changes in the collagen fibers of the dermis. The proposed technique shows promise for in vivo non-invasive real-time assessment of age-associated skin changes and can also be extended to monitor changes associated with the development of age-related pathologies.

LEF1 isoforms regulate cellular senescence and aging.

The study of aging and its mechanisms, such as cellular senescence, has provided valuable insights into age-related pathologies, thus contributing to their prevention and treatment. The current abundance of high-throughput data combined with the surge of robust analysis algorithms has facilitated novel ways of identifying underlying pathways that may drive these pathologies. For the purpose of identifying key regulators of lung aging, we performed comparative analyses of transcriptional profiles of aged versus young human subjects and mice, focusing on the common age-related changes in the transcriptional regulation in lung macrophages, T cells, and B immune cells. Importantly, we validated our findings in cell culture assays and human lung samples. Our analysis identified lymphoid enhancer binding factor 1 (LEF1) as an important age-associated regulator of gene expression in all three cell types across different tissues and species. Follow-up experiments showed that the differential expression of long and short LEF1 isoforms is a key regulatory mechanism of cellular senescence. Further examination of lung tissue from patients with idiopathic pulmonary fibrosis, an age-related disease with strong ties to cellular senescence, revealed a stark dysregulation of LEF1. Collectively, our results suggest that LEF1 is a key factor of aging, and its differential regulation is associated with human and murine cellular senescence.

Blockade of interleukin-6 trans-signaling prevents mitochondrial dysfunction and cellular senescence in retinal endothelial cells

Interleukin-6 (IL-6) is a multifaceted cytokine implicated in the pathogenesis of diabetic retinopathy (DR). Its activity extends through cis- and trans-signaling (TS) pathways, with cis-signaling limited to specific cell types possessing the membrane-bound IL-6 receptor, while trans-signaling broadly activates various cells without the membrane bound IL-6 receptor, including retinal endothelial cells. In this study, we determined the effects of interleukin-6 trans-signaling on mitochondrial dysfunction and cellular senescence in human retinal endothelial cells (HRECs). HRECs were cultured and treated with IL-6 + soluble IL-6R or Hyper IL-6 to activate trans-signaling, along with sgp130Fc for inhibition. RT-PCR was used to analyze gene expression changes associated with inflammation and senescence. Cellular senescence was assessed using SA β-gal staining. Mitochondrial function was evaluated using Seahorse XFe24 Bioanalyzer. IL-6 trans-signaling induced inflammatory gene expression as indicated by the upregulation of ICAM1, MCP1, and SERPINA3 levels. Additionally, it reduced mitochondrial respiration and oxidative phosphorylation, and these effects were counteracted by sgp130Fc. Moreover, IL-6 trans-signaling led to altered expression of apoptosis-associated genes, including downregulation of FIS1, BCL2, and MCL1, while promoting cellular senescence, a phenomenon mitigated by sgp130Fc. These results not only deepen our understanding of IL-6 in DR but also carry broader implications for age-related diseases and the aging process itself. This study underscores the potential therapeutic value of targeting IL-6 trans-signaling with sgp130Fc as a promising anti-inflammatory approach for DR and potentially other inflammatory conditions. Further in-vivo investigations are warranted to elucidate the function of IL-6 trans-signaling in aging-related pathologies and overall organismal health.

Abstract 13753: Cumulative Circulating Monocyte Load is Associated With All-Cause Mortality: A Longitudinal Cohort Study

Introduction: Monocytic inflammation has been increasingly linked to diverse cardiometabolic risk factors and many age-related pathologies. Hypothesis: Cumulative monocyte counts (CumMON) are associated with and predictive of all-cause mortality. Methods: Retrospective analyses of data among 43,681 Han Chinese participants from a real-world, prospective cohort (Kailuan Study). Multivariable-adjusted Cox regression analyses were conducted to examine CumMON-associated risks for all-cause mortality. Results: Over a median 7.76 (IQR: 7.47-8.03) years of follow-up, 2,810 all-cause deaths were documented. Elevated monocyte load was significantly associated with higher mortality rates ( Figure 1 ). Each 1-SD increase in CumMON was associated with a 15% increase in all-cause death (1.15, 95% CI: 1.11-1.20) after adjusting for other risk factors. Higher death incidences and CumMON-associated mortality risks (per-SD increment) were observed in elderly individuals, participants with diabetes (1.18, 95% CI: 1.10-1.27), hypertension (1.16, 95% CI: 1.11-1.21), impaired renal function (1.18, 95% CI: 1.13-1.24), increased LDL-C (1.21, 95% CI: 1.15-1.28 for LDL≥2.6 mmol/L) or decreased HDL-C levels (1.21, 95% CI: 1.12-1.31), but not with CVD or cancer. There were significant supra-additive interactions between elevated CumMON and diabetes (RERI: 0.26, 95% CI: 0.04–0.48), hypertension (RERI: 0.35, 95% CI: 0.12–0.57), and old age (≥60 years) (RERI: 0.46, 95% CI: 0.07–0.85). The addition of cumulative monocyte load into the multivariable model significantly improved the prediction performance of all-cause death (net reclassification improvement: 12.05%; P <0.0001). Conclusions: Elevated cumulative monocyte load is significantly associated with all-cause death and improves risk prediction. Chronically elevated monocytes supra-additively enhance the mortality risk among those with old age, diabetes, or hypertension.

CD133+ endothelial-like stem cells restore neovascularization and promote longevity in progeroid and naturally aged mice

The stem cell theory of aging dictates that a decline in the number and/or function of stem cells causes tissue degeneration and aging; however, it still lacks unequivocal experimental support. Here, using lineage tracing and single-cell transcriptomics, we identify a population of CD133+ bone marrow-derived endothelial-like cells (ELCs) as potential endothelial progenitor cells, which contribute to tubular structures in vitro and neovascularization in vivo. We demonstrate that supplementation with wild-type and young ELCs respectively restores neovascularization and extends lifespan in progeric and naturally aged mice. Mechanistically, we identify an upregulation of farnesyl diphosphate synthase (FDPS) in aged CD133+ ELCs—a key enzyme in isoprenoid biosynthesis. Overexpression of FDPS compromises the neovascularization capacity of CD133+ ELCs, whereas FDPS inhibition by pamidronate enhances neovascularization, improves health measures and extends lifespan in aged mice. These findings highlight stem cell-based strategies for the treatment of progeria and age-related pathologies.