Aging Cell最新文献

Idiopathic pulmonary fibrosis (IPF) is an age-associated disease characterized by the irreversible accumulation of excessive extracellular matrix components by activated myofibroblasts (aMYFs). Following bleomycin administration in young mice, fibrosis formation associated with efficient resolution takes place limiting the clinical relevance of this model for IPF. In this study, we used aged mice in combination with bleomycin administration to trigger enhanced fibrosis formation and delayed resolution as a more relevant model for IPF. Alveolosphere assays were carried out to compare the alveolar resident mesenchymal niche activity for AT2 stem cells in young versus old mice. Lineage tracing of the Acta2+ aMYFs in old mice exposed to bleomycin followed by scRNAseq of the lineage-traced cells isolated during fibrosis formation and resolution was performed to delineate the heterogeneity of aMYFs during fibrosis formation and their fate during resolution. Integration of previously published similar scRNAseq results using young mice was carried out. Our results show that alveolar resident mesenchymal cells from old mice display decreased supporting activity for AT2 stem cells. Our findings suggest that the cellular and molecular mechanisms underlying the aMYFs formation and differentiation towards the Lipofibroblast phenotype are mostly conserved between young and old mice. In addition to persistent fibrotic signaling in aMYF from old mice during resolution, we also identified differences linked to interleukin signaling in old versus young alveolar fibroblast populations before and during bleomycin injury. Importantly, our work confirms the relevance of a subcluster of aMYFs in old mice that is potentially relevant for future management of IPF.

As global life expectancy increases, the focus has shifted from merely extending lifespan to promoting healthy aging. GSTA1, GSTA2, and GSTA3 (GSTA1-3), members of the alpha class of glutathione S-transferases, are involved in diverse biological processes, including metabolism and immune regulation, highlighting their potential influence on human health span and lifespan. In this study, we employed Caenorhabditis elegans as a model organism to investigate the role of gst-35, an ortholog of mammalian GSTA1-3, in healthy aging. Our results demonstrated that gst-35 overexpression has detrimental effects on multiple physiological functions in nematodes. Specifically, gst-35 overexpression significantly reduced lifespan, impaired development and growth, and substantially diminished reproductive capacity, physical fitness, and stress resistance. In contrast, gst-35 knockout partially enhanced physical fitness and stress resistance. Comprehensive RNA-sequencing transcriptome analysis revealed that gst-35 overexpression disrupted metabolic homeostasis and induced lysosomal dysfunction. These effects were mediated through the activation of the pmk-1 signaling pathway and suppression of skr genes, which collectively impaired healthy aging processes. These findings illuminate the complex role of gst-35 in aging and provide valuable insights into the molecular mechanisms underlying healthy aging, offering potential targets for interventions aimed at promoting health span.

Invertebrate models have been instrumental in advancing our understanding of the molecular mechanisms of ageing. The isolation of single gene mutations that both extend lifespan and improve age-related health have identified potential targets for therapeutic intervention to alleviate age-related morbidity. Here, we find that genetic loss of function of the G protein-coupled metabotropic glutamate receptor (DmGluRA) in Drosophila extends the lifespan of female flies. This longevity phenotype was accompanied by lower basal levels of oxidative stress and improved stress tolerance, and differences in early-life behavioural markers. Gene expression changes in DmGluRA mutants identified reduced ribosome biogenesis, a hallmark of longevity, as a key process altered in these animals. We further show that the pro-longevity effects of reduced DmGluRA signalling are dependent on the fly homologue of Fragile X Mental Retardation Protein (FMRP), an important regulator of ribosomal protein translation. Importantly, we can recapitulate lifespan extension using a specific pharmacological inhibitor of mGluR activity. Hence, our study identifies metabotropic glutamate receptors as potential targets for age-related therapeutics.

Dementia, characterized by loss of cognitive abilities in the elderly, poses a significant global health challenge. This study explores the role of astrocytes, one of most representative glial cells in the brain, in mitigating cognitive decline. Specifically, we investigated the impact of Hevin (also known as SPARC-like1/SPARCL-1), a secreted glycoprotein, on cognitive decline in both normal and pathological brain aging. By using adeno-associated viruses, we overexpressed Hevin in hippocampal astrocytes of middle-aged APP/PSEN mice, an established Alzheimer's disease (AD) model. Results demonstrated that Hevin overexpression attenuates cognitive decline, as evidenced by cognitive tests, increased pre- and postsynaptic markers colocalization, and altered expression of synaptic mediators, as revealed by proteomic profiling. Importantly, Hevin overexpression did not influence the deposition of Aβ plaques in the hippocampus, a hallmark of AD pathology. Furthermore, the study extended its findings to middle-aged wild-type animals, revealing improved cognitive performance following astrocytic Hevin overexpression. In conclusion, our results propose astrocytic Hevin as a potential therapeutic target for age-associated cognitive decline.

DNA topoisomerases are essential molecular machines that manage DNA topology in the cell and play important roles in DNA replication and transcription. We found that knocking down the enzyme topoisomerase Top2 or its mammalian homolog TOP2B increases the lifespan of S. cerevisiae, C. elegans, and mice. TOP2B reduction also extends the health span of mice and alleviates the pathologies of aging in multiple tissues. At the cellular/molecular level, TOP2B reduction alleviates the major hallmarks of aging, including senescence, DNA damage, and deregulated nutrient sensing. We observed that TOP2B reduction changes the epigenetic landscape of various tissues in old mice toward that of the young animals, and differentially downregulates genes with active promoter and high expression. Our observations suggest that Top2 reduction confers pro-longevity effect across species possibly through a conserved mechanism and may be a promising strategy for longevity intervention.

Despite the high prevalence of age-dependent intervertebral disc calcification, there is a glaring lack of treatment options for this debilitating pathology. We investigated the efficacy of long-term oral K₃Citrate supplementation in ameliorating disc calcification in LG/J mice, a model of spontaneous age-associated disc calcification. K₃Citrate reduced the incidence of disc calcification without affecting the vertebral bone structure, knee calcification, plasma chemistry, or locomotion in LG/J mice. Notably, a positive effect on grip strength was evident in treated mice. FTIR spectroscopy of the persisting calcified nodules indicated K₃Citrate did not alter the mineral composition. Mechanistically, activation of an endochondral differentiation in the cartilaginous endplates and nucleus pulposus (NP) compartment contributed to LG/J disc calcification. Importantly, K₃Citrate reduced calcification incidence by Ca²⁺ chelation throughout the disc while exhibiting a differential effect on NP and endplate cell differentiation. In the NP compartment, K₃Citrate reduced the NP cell acquisition of a hypertrophic chondrocytic fate, but the pathologic endochondral program was unimpacted in the endplates. Overall, this study for the first time shows the therapeutic potential of oral K₃Citrate as a systemic intervention strategy to ameliorate disc calcification.

Longevity individuals have lower susceptibility to chronic hypoxia, inflammation, oxidative stress, and aging-related diseases. It has long been speculated that "rejuvenation molecules" exist in their blood to promote extended lifespan. We unexpectedly discovered that longevity individuals exhibit erythrocyte oxygen release function similar to young individuals, whereas most elderly show reduced oxygen release capacity. Untargeted erythrocyte metabolomics profiling revealed that longevity individuals are characterized by youth-like metabolic reprogramming and these metabolites effectively differentiate the longevity from the elderly. Quantification analyses led us to identify multiple novel longevity-related metabolites within erythrocytes including adenosine, sphingosine-1-phosphate (S1P), and glutathione (GSH) related amino acids. Mechanistically, we revealed that increased bisphosphoglycerate mutase (BPGM) and reduced MFSD2B protein levels in the erythrocytes of longevity individuals collaboratively work together to induce elevation of intracellular S1P, promote the release of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from membrane to the cytosol, and thereby orchestrate glucose metabolic reprogramming toward Rapoport-Luebering Shunt to induce the 2,3-BPG production and trigger oxygen delivery. Furthermore, increased glutamine and glutamate transporter expression coupled with the enhanced intracellular metabolism underlie the elevated GSH production and the higher anti-oxidative stress capacity in the erythrocytes of longevity individuals. As such, longevity individuals displayed less systemic hypoxia-related metabolites and more antioxidative and anti-inflammatory metabolites in the plasma, thereby healthier clinical outcomes including lower inflammation parameters as well as better glucose-lipid metabolism, and liver and kidney function. Overall, we identified that youthful erythrocyte function and metabolism enable longevity individuals to better counteract peripheral tissue hypoxia, inflammation, and oxidative stress, thus maintaining healthspan.

Increased life expectancy is associated with a higher risk of age-related diseases, which represent a major public health challenge. Animal models play a crucial role in aging research, enabling the study of diseases at the organism level and facilitating drug development and repurposing. Among these models, zebrafish stands out as an excellent in vivo system due to its unique characteristics. However, the longevity of zebrafish is a limitation for research, as it often takes too long to obtain results within a reasonable timeframe. To address this, we have developed a short telomere zebrafish line (ST2) with a premature aging phenotype during the larval stage. Although less extreme than the tert-deficient G2 larvae, ST2 larvae exhibit reduced telomerase expression and activity, along with shortened telomeres. they also exhibit increased cellular senescence, apoptosis, and premature death. As a proof of concept, we evaluated the antiaging effects of two compounds: resveratrol (a polyphenol) and navitoclax (a senolytic). Our results confirm the antiaging properties of resveratrol, which improves telomere maintenance. However, navitoclax does not attenuate the ST2 phenotype. Taking advantage of the zebrafish larval model, this premature aging system provides a valuable platform for in vivo testing of rejuvenating molecules through drug screening, using telomere length or survival as a readout.

The trade-off between reproduction and lifespan has been documented across a wide array of organisms, ranging from invertebrates to mammals. In malnourishing dietary conditions, inhibition of the reproductive processes generally extends the lifespan of females. However, the underlying mechanisms through which nutritional competition driven by reproduction accelerates aging remain poorly understood. Here, using female Drosophila melanogaster as a model, we show that among various dietary conditions lacking specific nutrients, only sterol deficiency significantly exacerbated both the incidence and severity of intestinal barrier deterioration during aging. Sterile mutation specifically ameliorated such damage in sterol-deprived diets, but failed to alleviate age-related intestinal barrier deterioration under other nutritional conditions. Additionally, we demonstrate that the lifespan extension and intestinal barrier amelioration, accompanied by a reproductive suppression effect, through the pharmacological inhibition of mTOR or Ras-Erk signaling using rapamycin or trametinib, were significantly modulated by cholesterol levels. Our study also identifies the morphological changes in excreta as a sensitive biomarker for early intestinal dysfunction. Collectively, these results suggest that the impairment of the intestinal barrier caused by reproductive-induced sterol competition constitutes a significant factor limiting female lifespan in nutritionally unbalanced diets. This work elucidates a salient aspect of the complex interplay between reproductive resource allocation and somatic maintenance, thereby enhancing our understanding of how diet impacts the aging process.

Aging increases the susceptibility to metabolic dysfunction-associated steatotic liver disease (MASLD). Liver sinusoidal endothelial cells (LSECs) help in maintaining hepatic homeostasis, but the contribution of age-associated LSECs dysfunction to MASLD is not clear. The aim of this study was to investigate the effect of aging-associated LSECs dysfunction on MASLD. Free fatty acid-treated AML12 cells were co-cultured with young and etoposide-induced senescent TSEC cells to evaluate the senescence-associated endothelial effects on the lipid accumulation in hepatocytes. In addition, young and aged rats were subjected to methionine-choline-deficient diet-induced metabolic dysfunction-associated steatohepatitis (MASH). Hepatic hemodynamics and endothelial dysfunction were evaluated by in situ liver perfusion. Liver tissue samples from young and aged healthy controls and MASH patients were also analyzed. Steatotic AML12 cells co-cultured with young TSEC cells showed less lipid accumulation, and such effect was abolished by eNOS inhibitor or with senescent TSEC cells. However, co-culture with resveratrol-treated senescent TSEC cells could partially resume the NO-mediated protective effects of endothelial cells. Furthermore, aged MASH rats showed more severe liver injury, steatosis, fibrosis, and endothelial and microcirculatory dysfunction. In addition, aged MASH patients showed more pronounced liver injury and fibrosis with lower hepatic eNOS, p-eNOS, and SIRT1 protein levels than in young patients. Senescence compromises the protective effects of LSECs against hepatocyte steatosis. In addition, aging aggravates not only liver steatosis and fibrosis but also intensifies LSECs dysfunction in MASH rats. Accordingly aged MASH patients also showed endothelial dysfunction with more severe liver injury and fibrosis.